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We chose to question the narrative of history by simply quoting words which Churchill used himself.
At a glance, Blighty Café appears to be another one of those trendy and sophisticated coffee shops that offer the terribly appealing combination of tasteful beverages, off-beat music and the inviting aroma of freshly-baked sourdough bread. As a university student living in the area, of course, I couldn’t resist. Sounds perfect, right? Except, sitting in the mock air-raid shelter, drinking my flat white, I couldn’t help but feel ever more uncomfortable.
Blighty Café is located in North London and is not your average hipster café; Churchill memorabilia abounds, the outside area is modelled as a Second World War air-raid shelter, and there is even a life size model of Churchill so you can sip your coffee in the company of the revered wartime leader. Harmless? Chic? Unfortunately, the more I thought about it, the more I felt that it was deeply disrespectful to glorify Winston Churchill, without mentioning those who truly suffered at the hands of colonial rule.
Being of mixed Pakistani and English descent, colonial history has always been very close to home, and uncovering the horrors of British imperialism was a deeply upsetting experience. Churchill cannot be disentangled from this bloody colonial history. His instrumental involvement in the Bengal famine, his blasé attitude towards South African concentration camps and declarations such as “the Aryan stock is bound to triumph” have understandably lead me to question his heroism. With all this in mind, when my flatmate invited me to attend a surprise performance protesting against the café’s decor, I felt my presence would be justified.
“CHURCHILL WAS A RACIST!” Fifteen of us visited the packed-out Blighty Café on a windy Saturday morning. A silence fell amongst the customers as we recited Churchill’s racist outbursts; people were listening quite intently. Our performance lasted no more than five minutes. There was surprisingly (or perhaps unsurprisingly) little friction; except for one member of the cafe’s staff shouting at us as we left: “Churchill fought for all of our freedom!” I felt such a response rather confusing after we had just quoted Churchill as saying: “I hate Indians. They are a beastly people with a beastly religion.” I pondered on the man’s retort on the way home; yes, Churchill did fight for all of our freedom, but he also hated South Asians and said that they followed a beastly religion. Should I then be content with businesses in my local area celebrating his legacy?
The coverage of the protest by The Sun and The Daily Mail in the days following our performance have triggered a racist backlash, with one member of the group singled out for character assassination. We might have intended to make people feel a bit uncomfortable, but at the end of the day it was a peaceful protest. Rather than personal attacks, the newspapers could engage in a debate about our historical narratives. The coverage also noted that, like many young people, some of our group supported Labour leader Jeremy Corbyn. Yet we did not choose to involve Corbyn in our performance, and of course he is entitled to his own opinion on these matters.
On the café’s website, it is stated: “Blighty’s mission is to make the world a closer place by celebrating and improving the relationships between the people and nations of the 52 members of the commonwealth.” That sounds wonderful. I just don’t believe that glorifying figures of history with racist views is the right way to do so. The owner of the café told The Sun that Churchill did “some racist and ignorant things” but his flaws “showed he was human”. If I could ask the café owner to do one thing, it would be to read more into the darker side of Churchill’s legacy, and its effects on colonised people.
We chose to question the narrative of history by simply quoting words which Churchill used himself. It seems ludicrous that the press are so keen to shut us down. One has to ask whether they are silencing a group of students or the words of Churchill which they would rather forget.
The Blighty Café did not respond to a request for comment, but the owner has written an article about his establishment here. |
Aroma classification and characterization of Lactobacillus delbrueckii subsp. bulgaricus fermented milk Highlights The aroma types of fermented milk produced by L. bulgaricus were divided into milky-type, cheesy-type, fermented-type and miscellaneous-type. The flavor fingerprints of different aroma types were established by GC-IMS. Acetaldehyde, 2,3-butanedione, acetic acid, butanoic acid, hexanoic acid and -decalactone of different aroma types were determined by Flavoromics. Introduction Yogurt is a popular dairy product and is usually produced using the combination of L. bulgaricus and Streptococcus thermophilus (). Because of its unique flavors and health-improving functions, such as providing vitamins D and calcium (), regulating gut microbiota, and enhancing immunity (), yogurt is favored by the consumers worldwide. Flavor is an essential factor in yogurt quality, affecting consumers' acceptance. There are many kinds of yogurts in the market, for example, plain yogurt, fruity yogurt, cheesy yogurt, etc. The flavor diversity was achieved by adding spices or juice in yogurt processing (Routray & Mishra, et al., 2016) and 2,3-butanedione were regarded as important indexes for screening aroma-producing strains. However, there was no consistent conclusion about the effects of these compounds on the aroma of yogurt. Chinese liquor (Baijiu), which enjoyed a long history, could be divided into several aroma types such as Luzhou-flavor, Maotai-flavor, etc. (). The typing methods of baijiu aroma may be used as a reference to classify the aroma types of yogurts according to the sensory analysis. The volatile compounds in yogurts of different aroma types could be analyzed by gas chromatography-mass spectrometry (GC-MS) to determine the key flavor compounds. Then, the key flavor compounds could be selected as the indicators for screening strains with specific aroma and flavor, which might be an effective way to solve the homogenization problem in yogurt flavor. In recent decades, some new technologies such as gas chromatography-ion mobility spectrometry (GC-IMS) have emerged in food flavor research. GC-IMS has the advantages of high sensitivity, simple sample preparation, and short analysis time. However, GC-IMS could not provide a reliable qualitative determination as GC-MS. Therefore, the combination of GC-MS and GC-IMS could be an excellent choice to provide a comprehensive analysis of volatile components in yogurts. So far, >90 volatile compounds have been identified in yogurts. However, not all of these compounds could be detected by human olfactory receptors and contribute to the aroma of yogurt. The aroma-active compounds could produce the odor perception in the human brain (). Recently, sensomics or flavoromics has been applied to identify the key aroma-active compounds in dairy products. The flavor of milk fan (), kurut and cheeses () was investigated by flavoromics. In this study, to type the aroma of fermented milk produced by L. bulgaricus, the sensory properties of fermented milk produced by 28 L. bulgaricus strains were analyzed and the types of aromas were classified based on sensory analysis; The fingerprints and the key aromaactive compounds of specific aroma types were investigated by GC-IMS and flavoromics approach. Strains Starter cultures for dairy products were collected from a local market in Tsingtao, Shandong Province, China. The starter cultures were homogenized in 0.9% NaCl solution. Dilutions up to 10 -4 ~ 10 -6 were prepared, and 100 L aliquots from the 10 -4 to 10 -6 dillutions were spread onto MRS agar plates (Qingdao Hopo Bio-Technology Co., Ltd, China) and incubated at 37 ℃ under anaerobic conditions. Colonies were subjected to the catalase test and gram staining. Catalase-negative, gram-positive and rod-shaped colonies were purified two or three times in MRS agar plates (Hajimohammadi ). Pure colonies were identified by 16S rRNA gene sequencing in Sangon Biotech (Shanghai, China) Co., Ltd. A total of 28 L. delbrueckii subsp. bulgaricus strains were finally isolated and kept at − 80 ℃. The information on these L. bulgaricus strains is shown in Table S1. The strains were subcultured three times using a milk medium (Qingdao Hopo Bio-Technology Co., Ltd, China) for 18 h at 37 ℃ before use. Preparation of fermented milk Sterilized whole milk containing 3.0% protein (wt/vol) and 3.7% fat (wt/vol) was provided by a dairy company (Beijing Sanyuan Foods Co., Ltd), and 6% sucrose (wt/vol) was added. Then, the raw milk was pasteurized at 95 ℃ for 5 min and cooled quickly to 42 ℃. L. bulgaricus was inoculated into the raw milk with an inoculum size of 0.5% (vol/ vol) and fermented at 42 ℃. When the titratable acidity (TA) reached above 60 T, the fermentation process was ended immediately by an ice bath. The measurement of TA was conducted following ISO/TS 11869:2012(ISO/IDF, 2012. Then, quantitative descriptive and instrumental analysis were performed after refrigerating the fermented milk at 4 ℃ for 24 h. Each sample was fermented by L. bulgaricus strain according to the above manufacturing method twice. Quantitative descriptive analysis (QDA) According to the method given by ISO 8586: 2012(ISO, 2012, thirty students and staffs of the College of Food Science and Engineering of the Ocean University of China were invited as panel candidates, and they have been trained in relevant courses and have experience in sensory analysis. Thirty candidate panelists were trained for one month (1 h/ day) to familiarize, identify and describe the odorants commonly found in dairy products. Ten panelists (two males and eight females; average age of 25 years old) were selected based on availability and sensory perception abilities. Meanwhile, these ten panelists were retrained and asked to sniff the standard reference and grade the intensities of different aroma attributes. Besides, the training and selection of panelists and the formal descriptive sensory analysis were performed in a sensory laboratory of the College of Food Science and Engineering of Ocean University of China where the room temperature was controlled at 20 ℃. Referring to the ISO 5492: 2008, five sensory descriptors including milky, creamy, cheesy, buttery and fermented were selected, and the definition and references of these five descriptors is shown in Table S2. A continuous 9-point scale, ranging from 0 (absence of the attribute) to 9 (very high intensity of the attribute), was used to measure aroma intensity. The scale of intensity for each reference was set as 7 points. Ten grams of fermented milk samples were weighed in disposable taste glass and coded with random three-digit codes at approximately 10 ℃. Each fermented milk sample was measured in triplicate. The panel evaluated 10 ~ 12 samples during each 120-min session, and 16 total sessions were held to evaluate the 28 samples in three replicates. The panelists could have a rest after they evaluated 4 ~ 5 samples. The data of sensory analysis were collected manually. To ensure the accuracy and reliability of the sensory evaluation, the professionals engaged in the R&D of dairy starters from the company Beijing Doit Biotechnology Co., Ltd were commissioned to guide and supervise our work of sensory analysis. HS-GC-IMS analysis One gram of fermented milk was placed into a 25-mL headspace glass sampling vial, which was incubated at 55 ℃ for 20 min at 500 rpm/min. After the incubation, 500 L of headspace was automatically sucked and transferred into the GC-IMS instrument (FlavorSpec, GAS, Germany). A WAT-Wax capillary column (15 m 0.53 mm) was chosen for volatile separation at isothermal 60 ℃. Nitrogen (purity ≥ 99.999%) was used as the carrier gas, the flow rate of which was set as follows: 2 mL/min (0 to 2 min), 2 ~ 10 mL/min (2 to 10 min), 10 ~ 100 mL/min (10 to 15 min), 100 ~ 150 mL/min (15 to 20 min), 150 mL/min (20 to 30 min). The draft tube was under 45 ℃, where nitrogen was used as a drift gas at 150 mL/min flow. The data was processed by LAV (Laboratory Analytical Viewer) and GC IMS Library Search. The retention index (RI) of volatile compounds was calculated using n-ketones C 4 ~ C 9 as external references for the identification of compounds. Each fermented milk sample was analyzed in triplicate. GC-MS analysis HS-GC-MS was used to analyze the volatile compositions of the fermented milk samples. Ten grams of samples were put into a 40-mL glass vial with a silicon septum and 2 L solution of 2-octanol (GmbH, Augsburg, Germany) with 0.328 mg/L were added as an internal standard. Then, the glass vial was equilibrated at 55 ℃ for 20 min and the SPME fiber coated with 50/30 m divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) was headed to the headspace of the vial for volatile extraction at 55 ℃ for 40 min. After extraction, the fiber was inserted into the injector port of GC-MS and desorbed for 6 min at 250 ℃ in splitless mode. The GC-MS analysis was operated using an Agilent 8890 GC/7000D MSD according to and Dan et al. with minor modifications. The volatile compounds were determined on a capillary column Agilent HP-INNOWax column (60 m 0.25 mm, 0.25 m, Agilent Technologies) and a capillary column Agilent HP-5MS column (30 m 0.25 mm, 0.25 m, Agilent Technologies). For the HP-INNOWax column, the oven temperature was held at 35 ℃ for 3 min firstly, then increased to 120 ℃ at a rate of 4 ℃/min and then increased to 190 ℃ at 5 ℃/min, and finally increased to 230 ℃ at 10 ℃/min and held for 6 min. For the HP-5MS column, the oven temperature was maintained at 35 ℃ for 3 min firstly, and increased to 100 ℃ at a rate of 4 ℃/min and held for 2 min, then increased to 150 ℃ at 5 ℃/min, and finally increased to 250 ℃ at 10 ℃/min and held for 10 min. The volatile compounds were identified by MS and retention index (RI). The RI was calculated with a series of n-alkanes (C 7 ~ C 30 ). GC-O-MS analysis The aroma-active compounds were located using Agilent 7890B-5977B GC/MSD equipped with an olfactory detection part (Gerstel ODP-2, Mlheim an der Ruhr, Germany). The GC effluent was set to be separated equally between the mass detector and the sniffer in a 1:1 ratio. A capillary column Agilent HP-INNOWax column (60 m 0.25 mm, 0.25 m) was chosen to separate the volatile compounds and the operating conditions were the same as the description in GC-MS analysis. The odor-specific magnitude estimation (OSME) analysis was conducted to evaluate the odor intensities of volatile compounds by ten well-trained panelists. The procedure of selection and training of panelists was the same as the description in session 2.4 Quantitative descriptive analysis (QDA). The time of the onset and end of the aromaactive compounds, the perceived odor characteristic, and aroma intensity (AI) were recorded. AI was marked using the 6-point scale from 0 (none detected) to 5 (extremely strong). The GC-O-MS analysis was performed in triplicate by each panelist. The mean values of the AI marked by ten panelists were considered the final value of AI. To avoid potential loss of aroma-active compounds, the compound would be recognized as aroma-active compound when the AI value of one volatile compound was higher than zero. In addition to MS and RI, the odor descriptions of compounds and corresponding standard compounds were used for further identification of aroma-active compounds. Quantitative and OAV analysis The aroma-active compounds were quantified by establishing standard curves with GC-MS in SIM mode. To obtain a matrix similar to fermented milk, an aroma-blank matrix was prepared according to with minor modification. Firstly, 3% (wt/vol) milk protein concentrate powder (MPC 80, Ningxia Cezanne dairy industry Co., Ltd., Yinchuan, China), 3.6% (wt/vol) sunflower seed oil (COFCO Corporation, Beijing, China), water, 1% (wt/ vol) modified starch and 0.1% (wt/vol) pectin were mixed with a blender (2000 rpm/min, 55 ℃ for 30 min). The mixture was homogenized under 20 MPa and pasteurized at 95 ℃ for 5 min. Finally, the pH of the mixture was adjusted to 4.5 with lactate buffer solution. Ten grams of the mixture were added into a 40 mL glass vial with a silicon septum and 2-octanol was added as described above. The concentration gradient of each compound was set according to the semiquantitative results, and the standard curve of no<6 points was established. All calibration curves were replicated in triplicate. The calibration equations were listed in Table S6, where y represented the peak area ratio (peak area of standard compound / peak area of internal standard), and x represented the concentration ratio (concentration of standard compound /concentration of internal standard). The odor activity value (OAV) was calculated as the ratio of the concentration of compounds to its odor threshold. The odor thresholds of these compounds were collected from the information available in the literature (van Gemert, 2011). Each fermented milk sample was analyzed in triplicate. Aroma recombination To evaluate and compare the actual contribution of each aromaactive compound to the aroma profile of fermented milk samples, all of the aroma-active compounds were prepared at concentrations the same as their occurrence in the original samples in the aroma-blank mixture. After equilibrating at room temperature for 2 h, the aroma recombinant (AR) was finally obtained. Quantitative descriptive analysis (QDA) with ten well-trained panelists, as described in session 2.4, was used to evaluate the sensory scores of the recombination models and their corresponding samples. Omission tests To determine the compounds that influence the overall aroma profile of fermented milk samples, omission models based on the recombinant model were prepared by removing a single compound or a group of compounds from the recombination models. A total of 15 omission models and one recombination model were analyzed by a triangle test. Triangle tests were performed by randomly arranging one omission model and two recombination models for ten well-trained panelists to test whether or not there were some differences between the recombination models and the omission models and select the different one. If at least eight panelists recognized the omission models, it meant that this compound or this group of compounds omitted from the recombination model was or were significantly important to the overall aroma of samples (p < 0.05). Similarly, if there were nine panelists, it meant that this compound or this group of compounds was or were highly significantly important (p < 0.01), and 10 panelists meant very highly significantly important (p < 0.001) (). Each test was conducted in triplicate. Aroma addition experiments Aroma addition experiments were operated to further verify and explore the effects of the key aroma compounds on the intensities of aroma attributes. All aroma-active compounds were mixed in the aromablank mixture at the same concentrations as their occurrence in the original sample of L6-11 to obtain aroma recombinant (AR). Then, the key aroma compounds including acetaldehyde, 2,3-butanedione, acetic acid, butanoic acid, hexanoic acid, and -decalactone revealed by omission test, were added to the aroma recombinant L6-11 at concentrations similar to those in the sample of L6-11. The intensity changes in aroma attributes were quantified by ten well-trained panelists as described in session 2.4 Quantitative descriptive analysis (). The aroma addition experiments were performed in triplicate for every key aroma compound. Statistical analysis Data from the sensory analysis, quantitative analysis, and aroma recombination and addition analysis were evaluated by using an analysis of variance (ANOVA) with Duncan's multiple comparison tests performed by IBM SPSS Statistics version 25. Here, p-values of < 0.05, <0.01 and < 0.001 were considered statistically significant and marked as *, ** and ***, respectively. Radar maps and PCA analysis for the results of sensory analysis and aroma classification were carried out using Origin 2019b (OriginLab, Northampton, United States). Heatmap analysis for concentrations of the six key aroma compounds was performed in MetaboAnalyst 5.0 (https://www.metaboanalyst.ca). Sensory analysis and aroma typing The results of sensory analysis of the fermented milk produced by 28 L. bulgaricus are shown in Table 1. For the milky attribute, the samples of L6-12, L8-5, L9-2, L9-5, and L9-8 were the most scored with intensities of 3. The creamy attribute was only presented in the samples of L4-1-2, L6-11, L6-14, L8-4, L8-7, and L8-8, but it was weaker compared with cheesy, milky, and fermented attributes. For the cheesy attribute, L4-1-2 was the most scored with an intensity of 5, followed by L4-1-1, L4-2-3, L6-15, L8-6, L8-7, and L9-6 samples. For the fermented attribute, only the L6-11 sample was scored with an intensity higher than 5, followed by L9-5. Besides, the samples L6-12, L8-1 and L9-1 showed weak a buttery attribute. For quantitative descriptive analysis of the aroma of fermented milk, it is crucial to develop a sensory lexicon with definitions and scales. Some reports have shown some lexicons and references for aroma sensory evaluation of yogurt, such as grain-like, moldy, yeast, milk, sweaty, etc. (Brown & Chambers, 2015;). Considering the differences in dietary habits and cultures of different countries, we did not copy these lexicons completely. Instead, the lexicon including milky, creamy, cheesy, buttery, and fermented was finally determined according to the ISO 5492: 2008. Twenty-eight samples had obvious differences in all five aroma attributes. The L4-1-2 showed a prominent cheesy aroma, and the sample of L6-11 showed the most outstanding fermented aroma. Interestingly, all of the 28 fermented milk samples showed lower scores in the milky, creamy, and buttery aroma. These phenomena indicated that different L. bulgaricus strains had varying metabolizing abilities to produce flavor compounds during milk fermentation, which provided a theoretical basis to establish screening methods of strains with specific sensory notes. Referring to the classification methods of Chinese liquors, the rule of aroma typing in this study was set as follows: it would be assigned to the aroma type if a fermented milk sample had the highest score of a specific aroma attribute. Accordingly, the 28 fermented milk samples were divided into four aroma types: milky-type, cheesy-type, fermented-type, and miscellaneous-type, and the results are shown in Table 1. Miscellaneous type means that the scores of more than one attribute are the same and the highest. Four samples were grouped into milky-type, and 13, 7, and 4 fermented milk samples were classified into cheesy-type, fermented-type and miscellaneous-type, respectively. Radar maps of 4 different aroma types were structured according to the results of sensory analysis and are shown in Fig. 1. Among four fermented milk samples of the milky-type (Fig. 1a), L8-5 and L9-8 samples were the most scored with a milky intensity of 3. In cheesy-type (Fig. 1b), L4-1-2 showed the most robust cheesy aroma with an intensity of 5. Among seven fermented milk samples of fermented-type (Fig. 1c), L6-11 was the most scored with a fermented intensity of 6 followed by L9-5 with 5 points. As for the miscellaneous-type (Fig. 1d), L9-2 showed the same score for the milky and cheesy attribute, and L9-7 had the same score for the milky and fermented attribute. L9-4 and L9-13 were scored with the same intensity of cheesy and fermented attributes. The PCA plot derived from the aroma characterization is shown in Fig. 1e, which indicates a pictorial relationship among fermented milk samples of four aroma types based on the intensity of the five aroma attributes. PCA could reduce the dimensionality of aroma data and intuitively characterize the prominent aroma features of fermented milk samples (). After PCA analysis, the fermented milk Note: 1 The mean scores round to nearest integer. Attribute intensities were scored on a 0-to 9-point universal intensity scale where 0 indicates that the attribute is not perceived at all; 1 indicates doubt about the presence of the attribute; 2 indicates that the attribute is perceived but very slightly; 3 indicates that the attribute is clearly perceived, although it is slight; 4 indicates that the attribute is clearly perceived, but the intensity is much lower than reference; 5 indicates that the attribute is clearly perceived, but the intensity is lower than the reference; 6 indicates that the attribute is clearly perceived, but the intensity is slightly lower than the reference; 7 indicates that the intensity of the attribute is similar to the reference.; 8 indicates that the intensity of the attribute is higher than the reference; and 9 indicates that the intensity of attribute is much higher than the reference. 2 Different superscript letters in the same row indicated significant differences (p < 0.05). samples of four aroma types were differentiated on the plot. Samples of the milky-type were positively correlated with the milky attribute. Samples of the fermented-type were positively related to the fermented attribute and negatively correlated with the cheesy attribute. All of the 13 samples of the cheesy-type were positively correlated with the cheesy characteristic. Currently, no other study showed the viewpoints of aroma types of fermented milk, and the results of aroma typing in this study might offer suggestions to establish the aroma classification of fermented milk in the future to screen out novel strains with specific aroma features. Identification of volatile compounds by GC-IMS and GC-MS To elucidate the crucial compounds influencing the aroma typing, the volatile compounds of the two fermented milk samples were analyzed by GC-IMS, and the results are shown in Fig. 2. These two Fig. 2. 2D topographic plots of volatile compounds and the flavor fingerprints of two fermented milk samples selected. a. 2D-topographic plots of volatile compounds in two fermented milk samples selected. b. the differential plots of 2D-topographic plots of GC-IMS spectra of volatile compounds in two fermented milk samples selected (with the L4-1-2 as the background). c. The flavor fingerprints of two fermented milk samples selected. The areas of A and B were characteristic fingerprints of L4-1-2 and L6-11, respectively. d. The flavor fingerprints of unidentified plots in two fermented milk samples selected. The areas of C and D were characteristic fingerprints of L4-1-2 and L6-11, respectively. samples, including L4-1-2 (cheesy-type group) and L6-11 (fermentedtype group), showed the highest scores in their corresponding sensory attributes. It was observed that all of the samples of the milky-type and miscellaneous-type groups showed lower scores in five aroma attributes (<3 points), so the samples of these two types were not selected for subsequent GC-IMS and flavoromics analysis. 2D topographic plots of volatile compounds in fermented milk samples showed no obvious difference in the composition of volatile components of the two samples (Fig. 2a). The sample of L4-1-2 was set as the background, and the differential plots were obtained by topographic plot deduction and are shown in Fig. 2b. There were lots of plots that showed differences in colors, which suggested that lots of compounds in the two samples differed in concentrations. To describe the differences of volatile compounds between the L4-1-2 of cheesy-type and the L6-11 of fermented-type, integral and qualitative analyses were operated on the GC-IMS spectra. A total of 48 volatile compounds, including 10 aldehydes, 5 esters, 13 ketones, 2 acids, 11 alcohols, 4 sulfides and 3 others, were identified (Table S3). To demonstrate the differences of different aroma types, the flavor fingerprints of fermented milk samples were structured and are shown in Fig. 2c. A total of 26 volatile compounds were identified as key compounds, including 9 ketones, 3 aldehydes, 6 alcohols, 2 acids, 3 esters, 1 sulfide and 3 other compounds. These 26 compounds were divided into area A and area B. Area A consisted of 15 volatile compounds including 5 alcohols, 1 sulfide, 3 aldehydes, 1 easter, 4 ketones, and 1 other compound. Dimethyl disulfide could provide an onion and cabbage flavor for yogurt, and its concentration in L4-1-2 was higher than that in L6-11, which might cause L4-1-2 had a higher score in cheesy attribute than L6-11. Besides, there were also 3 aldehydes in area A, which came from an amino acid by transamination. (E)-2-pentanal and nonanal could give fruit and green smell to yogurt (;). Area B was mainly composed of acids, esters, and ketones. Acetic acid could improve the sour smell of yogurt. The concentration of acetic acid in L6-11 was higher than that in L4-1-2, which might be why the fermented score of L6-11 was higher than that of L4-1-2. 2-Nonanone, 3-hydroxy-2-butanone, and 2,3-butanedione, which offered a creamy aroma to yogurt, and the concentrations of these compounds in L6-11 were higher than those in L4-1-2, which might account for the higher creamy score of L6-11 than that of L4-1-2. Besides, the intensities of 33 unidentified plots were significantly different (Fig. 2d). Area C consisted of 9 unidentified plots where these 9 plots in L4-1-2 showed higher intensities than those in L6-11. Moreover, area D included 24 unidentified plots and their intensities in L6-11 were higher than those in L4-1-2. The volatile compounds in the two fermented milk samples, L4-1-2 and L6-11, were then investigated by GC-MS. The qualitative results of GC-MS are shown in Table S4. A total of 67 volatile compounds, including 9 aldehydes, 17 ketones, 13 organic acids, 12 alcohols, 3 lactones, 6 sulfides, 2 terpenes, and 5 other compounds, were identified. Comparing and integrating the qualitative results of GC-IMS and GC-MS, 48 volatile compounds were identified by GC-IMS, and 67 volatile compounds were identified by GC-MS. A total of 95 volatile compounds were identified via GC-IMS and GC-MS, and 21 volatile compounds were identified by both GC-MS and GC-IMS. It is worth noting that although GC-MS identified more compounds than GC-IMS, some compounds, including ethyl acetate, butyl acetate, small acid, ketones and alcohols were only identified by GC-IMS, due to its high sensitivity. Besides, there were 33 unidentified plots in GC-IMS spectra, which suggested that GC-IMS could not provide precise qualitative abilities as GC-MS. Therefore, the combination of GC-IMS and GC-MS could comprehensively analyze the volatile compounds in fermented milk. Identification of aroma-active compounds in fermented milk by GC-O-MS Although 95 volatile compounds were identified by GC-IMS and GC-MS, it could not confirm which compounds had aroma activities. Therefore, the aroma-active compounds were investigated by GC-O-MS analysis. Meanwhile, OMSE (odor-specific magnitude estimation) was performed to quantify the aroma-active compounds responsible for the aroma perception based on the aroma intensity (AI). Generally, higher AI values mean a more intense aroma and are important to the aroma of foods. A total of 12 aroma-active compounds, including 5 ketones, 4 acids, 2 aldehydes and 1 lactone, were perceived and identified in samples L4-1-2 and L6-11 by comparing their MS, RI, and odor descriptions with authentic standards ( Table 2). The RI, identification methods, and odor descriptions of the 12 aroma-active compounds are also shown in Table S5. In L4-1-2 and L6-11 were revealed 10 and 9 aroma-active compounds, respectively. From Table 2, 7 aroma-active were perceived in every fermented milk sample, among which 2,3-butanedione (1.38-1.85), butanoic acid (2.25-3.25), hexanoic acid (1.75-1.88), and -decalactone (2.75-3.25) presented relatively high AI values, and were therefore considered to be primary contributors to aroma of fermented milk. Ketones are usually produced by -oxidation in the fermentation process. A total of 5 ketones were perceived in two fermented milk samples selected and 2,3-butanedione had the highest aroma intensities, followed by 2-nonanone. 2-Pentanone and 3-hydroxy-2-butanone had lower aroma intensities (AI < 1) and fewer contributions to the aroma of fermented milk. Some reports showed that 2,3butanedione could provide a creamy aroma to fermented milk (), and it was perceived at similar intensities between the two samples selected. Two aldehydes, including acetaldehyde and benzaldehyde, showed lower aroma intensities compared to other aromaactive compounds, which suggested that aldehydes had little influence on the flavor of fermented milk. In addition, four organic acids, including acetic acid, butanoic acid, hexanoic acid, and octanoic acid, were regarded as the aroma-active compounds. Acetic acid, butanoic acid, and hexanoic acid could give strong sour, cheesy and rancid smells. Acetic acid, butanoic acid, and hexanoic acid were all screened out as aroma-active compounds in L4-1-2 and L6-11. Octanoic acid was only perceived in L6-11. Butanoic acid, hexanoic acid, and octanoic acid had higher aroma intensities (AI > 1), which indicated that these three acids played important contributions to the overall aroma of fermented milk. Meanwhile, acetic acid, hexanoic acid, and octanoic acid showed higher AIs in L6-11 than that in L4-1-2, and butanoic acid showed higher AIs in L4-1-2 than that of L6-11, which could explain the stronger fermented aroma of L6-11 and stronger cheesy aroma of L4-1-2. Besides, -decalactone which is produced mainly by hydrolysis and further esterification of hydroxy fatty acid triglycerides, showed creamy or coconut flavor (;) and was perceived at similar intensities between the two samples selected with the highest aroma intensity (AI > 2), which suggested that this compound played an indispensable role in the aroma of fermented milk samples. Ott et al. () analyzed aromaactive compounds in yogurt by GC-O, and 20 aroma compositions were perceived. However, only 11 aroma-active compounds were identified in their study, which differed from our study's results. This difference might be because that they adopted combined static and dynamic headspace and preparative simultaneous distillation-extraction under vacuum to extract the extraction aroma compositions which might be different from headspace solid microextraction in terms of extraction efficiency. Quantitation of aroma-active compounds in fermented milk The differences in AI values of aroma-active compounds were mainly due to the concentration differences. Therefore, quantitative analysis was performed to further evaluate the contributions of these aromaactive compounds. The quantitative results of these 12 aroma-active compounds are shown in Table 2. It was found that acetaldehyde, 3-hydroxy-2-butanone, acetic acid, butanoic acid, and hexanoic acid were present in relatively high concentrations (>1mg/kg). Conversely, 2-pentanone, 2,3-butanedione, heptanone, 2-nonanone, benzaldehyde, octanoic acid, and -decalactone presented lower concentrations (<1mg/ kg). The contributions of aroma-active compounds are not only determined by their concentrations but also by their odor threshold values. Therefore, the OAV values of aroma-active compounds were calculated to further analyze the contributions of aroma-active compounds. The results are shown in Table 2. The OAV values of 7 aroma-active compounds were higher than 1, including acetaldehyde (OAV 43.16-50.91), 2,3-butanedione (OAV 2.30-4.52), 2-heptanone (OAV 3.98-6.24), acetic acid (OAV 1.19-1.88), butanoic acid (OAV 1.06-1.66), hexanoic acid ) and -decalactone (OAV 9.70-13.06). They were regarded as contributors to the sample aroma based on the principle of OAVs. Among these seven compounds, 2,3-butanedione, butanoic acid, hexanoic acid, and -decalactone showed relatively high AI values, which were in accordance with the results of GC-O-MS analysis. Though -decalactone with a typical creamy aroma was present in very low concentration (24.24-32.66 ug/kg), it was regarded as an influential aroma contributor to fermented milk samples due to its extremely odor thresholds (0.0025 mg/kg). The results of GC-O-MS showed that the AI values of acetaldehyde were low in both two selected fermented milk samples, while its OAV value was the highest, which might be due to different mediums of GC-O-MS analysis and quantitative analysis. In GC-O-MS analysis, AI values were determined by panelists based on the threshold of acetaldehyde in the air (threshold value = 1 mg/m 3 ), which was different from its threshold in the milk (threshold value = 0.062 mg/kg) (van Gemert, 2011;). The OAV values of 2pentanone, 3-hydroxy-2-butanone, 2-nonanone, benzaldehyde, and octanoic acid were<1, which meant that these five aroma-active compounds would play an auxiliary role in the overall aroma of fermented milk. At the same time, these five aroma-active compounds were perceived by GO-O with low AI values, indicating a high consistency between GC-O-MS and quantitative analysis. Thus, seven aroma-active compounds were provisionally regarded as key aroma compounds of the fermented milk sample selected. Aroma recombination Though GC-O-MS and quantitative analysis were used to isolate and identify the aroma components from the food matrix, they could not reflect the real interactions among these aroma-active compounds. Therefore, aroma recombination was performed to verify qualitative and quantitative results of aroma-active compounds and to confirm the contribution of such compounds to the overall aroma. The results of aroma recombination analysis are shown in Fig. 3(a-b). All of the aromaactive compounds were prepared according to the concentrations in the original samples. The aroma of recombination models of L4-1-2 and L6-11 were shown good similarity with the original samples L4-1-2 and L6-11, respectively. However, there were still slight differences found in some aroma intensities, such as fermented, creamy, and cheesy. In aroma recombinant of L4-1-2 (Fig. 3a), the scores of fermented and cheesy attributes of aroma recombinant were significantly lower than those of L4-1-2 (p < 0.05). Meanwhile, the scores of fermented, creamy, and cheesy attributes in aroma recombinant of L6-11 (Fig. 3b) were significantly lower than those of L6-11 (p < 0.05). These differences were possibly caused by variable aroma release from different matrices. There were some gaps between the aroma-blank and the matrix of real fermented milk, which could influence the release of aroma compounds. Besides, it was reported that headspace solid microextraction showed poor extractability for the polar and semi-volatile compounds (), which could cause these differences. Aroma omission test To further verify the contributions of these 12 aroma-active compounds to the aroma profiles of fermented milk, omission tests were conducted using 15 models in which single compounds or a group of compounds were omitted. The recombined model of L6-11 was used as a guide, and omission models were evaluated by a triangle test. The statistical results are shown in Table 3. It could be seen that the omission of all ketones (model 1) showed a very highly significantly different aroma than that of the recombined model (p < 0.001), which indicated that ketones played essential roles in the overall aroma of fermented milk. The models omitting only 2,3-butanedione presented a highly significant difference (model 1-2, p < 0.01). The models omitting only 2-heptanone (model 1-3), 3-hydroxy-2-butanone (model 1-4), and 2nonanone (model 1-5) showed no significant difference compared with the recombined model of L6-11, which suggested that only 2,3butanedione responsible for creamy aroma played indispensable roles in the overall aroma of fermented milk among five ketone compounds. Besides, nine out of ten panelists recognized model 4 omitting -decalactone, which suggested -decalactone was another main contributor to the overall flavor of fermented milk. Meanwhile, -decalactone could confer coconut or creamy flavor. Nine panelists recognized model 2 lacking all aldehydes and model 2-1 omitting acetaldehyde. No panelist recognized the model omitting the benzaldehyde, which indicated that only acetaldehyde could play an indispensable role in the overall aroma of fermented milk. Acetaldehyde could give a rich milky aroma, which suggested that acetaldehyde might be the main Table 2 The aroma intensities of aroma-active compounds in two fermented milk samples obtained by GC-O-MS analysis and their concentrations and OAV values. Note: a The aroma intensity was obtained by GC-O-MS, and the aroma intensities of compounds were reported as the mean ± standard deviation (SD). b The concentrations of compounds were reported as the mean ± standard deviation (SD), and the values with different letters (a tod) in a row are significantly different using Duncan's multiple comparison tests (P < 0.05). contributor to the milky attribute of fermented milk samples. Furthermore, models 3 and 3-3, which lacked all acids showed very a highly significant difference (p < 0.001), and 8 and 9 panelists recognized models 3-1 lacking acetic acid and 3-2 lacking butanoic acid, respectively. Moreover, there was no significant difference between model 3-4 lacking octanoic acid and the recombined model of L6-11. Therefore, acetic acid, butanoic acid, and hexanoic acid were important aromaactive compounds. It is worth mentioning that acetic acid and butanoic acid were not found to have high OAV (OAV < 2), which could be explained why the current estimate of odor thresholds of these two compounds was not fully estimated (). Considering the results of the aroma recombination and aroma omission test, the conclusion could be drawn that acetaldehyde, 2,3-butanedione, acetic acid, butanoic acid, hexanoic acid, and -decalactone were the key aroma compounds of the fermented milk by L. bulgaricus. To reflect the composition differences of key aroma-active compounds in the fermented milk samples, the concentrations of the abovementioned key aroma compounds were presented in the form of a heatmap, as shown in Fig. 3c. Six compounds were divided into two clusters based on the dendrogram. Cluster 1 consisted of four aromaactive compounds, including 2,3-butanedione, hexanoic acid, acetic acid, and -decalactone. 2,3-Butanedione could provide creamy flavor, and its concentration in L6-11 was significantly higher than that in L4-1-2. The score of a creamy attribute of L6-11 was higher than that of L4-11, which suggested this compound might be the key aroma-active compound for the creamy attribute of fermented milk. It was worth noting that the threshold of 3-hydroxy-2-butanedione (threshold = 8 mg/kg) was much bigger than that of 2,3-butanedione (threshold = 0.05 mg/kg), and 2,3-butanedione could be irreversibly reduced to 3-hydroxy-2-butanedione by diacetyl reductase (Smid & Kleerebezem, 2014), thereby reducing the contribution of 2,3-butanedione to the creamy aroma of fermented milk. Therefore, the activity of diacetyl reductase should be considered when screening the strains with prominent creamy flavor. -Decalactone was proved to significantly contribute to a creamy odor ). Similar to 2,3-butanedione, the concentration of -decalactone in L6-11 was significantly higher than that in L4-1-2, suggesting that -decalactone might also be one of the main contributors to the creamy attribute of fermented milk samples. Besides, hexanoic acid and acetic acid could show a rich sour smell. It could be concluded that acetic acid and hexanoic acid might be the main contributors to fermented attributes. Cluster 2 contained two compounds, including acetaldehyde and butanoic acid. Butanoic acid could offer cheese flavor, and the concentration in L4-1-2 was significantly higher than that of L6-11, which suggested that butanoic acid might be the main contributor to the cheesy attribute. Effects of the addition of key aroma compounds on aroma attributes To further explore and verify the effects of the above six aromaactive compounds on aroma attributes of fermented milk, additional experiments were performed, and the results are shown in Fig. 3. The addition of acetaldehyde could improve the aroma intensities of the milky attribute significantly (p < 0.05), which indicated that acetaldehyde was an important contributor to milky attributes. When adding the 2,3-butanedione (Fig. 3e) and -decalactone (Fig. 3i) into the AR, the creamy intensities showed significant improvements (p < 0.05), which could be concluded that these two compounds contributed to the creamy attribute. Meanwhile, the additions of -decalactone could significantly improve the intensities of the milky attribute, suggesting that acetaldehyde and -decalactone might have some important synergistic olfactory effects. When acetic acid was added to AR, the intensity of fermented attribute increased from 4.9 to 5.33. Still, there was no significant difference (p > 0.05), which indicated that acetic acid was not the main contributor to the fermented aroma. The addition of hexanoic acid not only improved the aroma intensity of the fermented aroma significantly but also enhanced the cheesy aroma, which could be concluded that hexanoic acid was the main contributor to the fermented attribute, and some synergistic olfactory effects also existed in hexanoic acid and butanoic acid. Besides, the addition of 2,3butanedione (Fig. 3d) and hexanoic acid (Fig. 3h) could reduce the average aroma intensity of fermented attribute (from 4.9 to 4.5), milky attribute (from 0.92 to 0.5), and creamy attribute (from 1.83 to 1.19) to some extent, which suggested that there were some masking or inhibitory effects in aroma compounds (). In this study, the aroma types of fermented milk samples were based on a prominent aroma attribute of fermented milk samples. The score of cheesy attributes of L4-1-2 assigned to cheesy-type was higher than the other four aroma attributes, and butanoic acid was the main attributor of a cheesy attribute. Therefore, it could be concluded that the butanoic acid was the decisive aroma compound in cheesy-type. Similarly, hexanoic acid and acetic acid were the decisive aroma compounds in the fermented-type. Conclusions The aroma attributes of fermented milk samples by 28 L. bulgaricus were evaluated, and four aroma types, including milky-type, cheesytype, fermented-type and miscellaneous-type, were obtained. A total of 95 volatile compounds in cheese-type and fermented-type were identified by GC-IMS and GC-MS, and 12 aroma-active compounds were selected by GC-O-MS. Finally, six aroma-active compounds were determined as the key ones including 2,3-butanedione, -decalactone, acetaldehyde, butanoic acid, acetic acid, and hexanoic acid. Butanoic acid was the decisive aroma compound for the cheesy-type, and hexanoic acid was the decisive aroma compound of fermented-type. In the future, these compounds could be used as indicators to screen the strains with the characteristics of cheesy-types or fermented-types. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Table 3 Omission experiments from the recombination model. Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi. org/10.1016/j.fochx.2022.100385. |
The lipoidal derivatives of steroids as biosynthetic intermediates. The lipoidal derivatives of pregnenolone, prepared biosynthetically, were converted, by incubation with a mitochondrial-microsomal fraction from adrenal cortical tissue, into lipoidal derivatives of 17-hydroxy-pregnenolone and of dehydroisoandrosterone, thus proving that these pregnenolone derivatives can serve as substrates for 17-hydroxylase and for the lyase enzyme that converts a C21-17-hydroxy-20-ketol into a C19-17-ketosteroid. Three synthetically prepared esters of pregnenolone, the oleate, the linoleate, and the arachidonate, were also hydroxylated at C-17 by a similar adrenal preparation. With the synthetic substrates, however, the corresponding esters of dehydroisoandrosterone were not formed. |
NEW YORK (CNNMoney) -- New fees and poor customer service have sparked an exodus among big bank customers, many of whom switched to smaller institutions last year.
The defection rate for large, regional and midsize banks averaged between 10% and 11.3% of customers last year, according to a J.D. Power and Associates' survey of more than 5,000 customers who shopped for a new bank or account over the past 12 months. In 2010, the average defection rates ranged from 7.4% to 9.8%.
Meanwhile, small banks and credit unions lost only 0.9% of their customers on average last year -- a significant decline from the 8.8% defection rate they saw in 2010.
These smaller institutions were also able to attract many of the customers who left the big banks. Over the course of last year, 10.3% of customers who shopped for a new bank landed at these smaller institutions -- up from 8.1% in the prior year.
New and higher bank fees at the nation's biggest banks led many customers to switch to smaller institutions over the past year, with about a third of customers at big banks reporting fees as the reason for looking elsewhere.
"When banks announce the implementation of new fees, public reaction can be quite volatile and result in customers voting with their feet," said Michael Beird, director of the banking services practice at J.D. Power and Associates.
Checking account fees have been on the rise at the nation's biggest banks over the past year, and customer revolt against big banks really began to mount after Bank of America (BAC, Fortune 500) proposed a monthly fee for debit card use last fall.
Even though the bank later backtracked on its decision, the announcement led to a nationwide, social media-fueled "Bank Transfer Day", during which customers encouraged each other to dump their big banks for community banks and credit unions.
The report also found that many customers were already unhappy with the customer service at big banks, so when fees were announced or raised, there was even more of an incentive to switch institutions.
"Service experiences that fall below customer expectations are a powerful influencer that primes customers for switching once a subsequent event gives them a final reason to defect," said Beird.
More than half of all customers who said fees were the main reason for switching banks also said they had received poor customer service at their prior bank, he said. |
After Kavanaugh's nomination, what do we do now?
Last Saturday, the United States Senate voted to confirm Judge Brett Kavanaugh Brett Michael KavanaughGrassroots America shows the people support Donald Trump The Hill's Morning Report — Category 5 Mueller storm to hit today On The Money: Cain 'very committed' to Fed bid despite opposition | Pelosi warns no US-UK trade deal if Brexit harms Irish peace | Ivanka Trump says she turned down World Bank job MORE to the U. S. Supreme Court 50 to 48. As the lengthy, often frustrating confirmation process demonstrated, a majority of the Senate learned no lessons from Anita Hill’s testimony in 1992.
Along primarily partisan lines, the Senate voted to confirm a man accused of sexual assault by at least three women. The Senate choose to turn their backs on us, women and survivors of sexual assault and abuse. The shameful scam of a confirmation process showed Judge Kavanaugh’s political agenda and a temperament not suitable for the highest court in our land. Many different groups stood in opposition to his appointment.
It is unconscionable that the Senate confirmed his nomination with so many examples of his unsuitability as a justice and lack of integrity.
It is clear that for conservative and anti-choice members of the Senate, Kavanaugh’s long history of opposition to reproductive rights and access to abortion trumped all other possible considerations. Make no mistake, this was an entirely deliberate action. There are many conservative judges who have clear anti-choice judicial philosophies that would have been equally unpalatable to reproductive rights advocates, but who have not been accused of sexual assault. Kavanaugh’s confirmation was a punitive move to reinforce existing cultural norms that suppress the reporting of sexual assault and punish women who question such norms.
With all of this recent history, Kavanaugh will take his seat on the U. S. Supreme Court. Barring anything leading to the long and difficult process of removing a Supreme Court Justice or his decision to step down, Kavanaugh will be a member of the court for the immediate future. He could potentially sit on the court for decades. So, what do we do now?
I call on Justice Kavanaugh as well as the other sitting justices to respect not only the rule of law that is the foundation of our government but also existing federal law regarding abortion. When the right to privacy was recognized in the Roe v. Wade decision, it changed the lives of all women in the United States by making it unconstitutional for states to ban abortion.
Since 1973, people who can get pregnant have not been held hostage by their reproductive capacity. While states have been working to restrict access to abortion since 1973 — particularly after the 1993 decision in Planned Parenthood v. Casey that said that states had a legitimate legal interest in regulating abortion — states have been prohibited from out-right criminalizing abortion.
But restrictions are creating less access across the country and that is hurting all of us. There are currently several cases working their way through the appellate court system that the Supreme Court could decide to hear, and any of these cases could imperil access to abortion in much of the United States.
Four states have laws on the books that would immediately ban abortion in their state if Roe was overturned by the court. Nine states have laws that banned abortion before Roe that could be enforced if it is overturned. Seven states have laws that would put access to abortion in jeopardy without Roe. The anti-choice movement has been pushing for the passage of increasingly extreme legislation since Casey in an attempt not only to make abortion as difficult to obtain as possible, but also to make sure that there would be cases that could be appealed to an anti-choice stacked Supreme Court. Nine states have laws that protect access to reproductive health care. In these states, abortion will remain accessible to women even if Roe is overturned.
Women who live in states without access to abortion will be able to receive care there, if they can afford to travel that is. Women of color are already more harshly affected by restrictions on abortion because they earn less than white women. For low-income women, abortion can already be unobtainable from certain locations. Don’t be fooled, we are much further down the path to criminalizing abortion and that path was built over the backs and bodies of women of color and low income women. Lack of abortion access has caused so much destruction already, we cannot go back.
Our Supreme Court justices must recognize what is at stake if they do not act to protect our existing laws regarding abortion. Before 1973, women died without access to safe abortion services. Current abortion restrictions have put women in dangerous situations because, while abortion was still legal, it was inaccessible to them. Rosie Jimenez died in Texas after the passage of the Hyde Amendment that prohibited her from using her Medicaid to access a safe abortion is a stark reminder.
The stories of doctors who worked in “septic wards,” wards for women who were suffering from septicemia or blood infections from unsafe abortions, are another. In less dramatic circumstances are women who can’t provide for their existing families or who do not want to be pregnant. If abortion is illegal in much of the country, it will be effectively banned for all women without the resources to access it. Legal rights are meaningless without access, but lack of access can also nullify legal rights.
Julie A. Burkhart is the founder and CEO of Trust Women. Trust Women opens clinics that provide abortion care in underserved communities so that all women can make their own decisions about their healthcare. Follow her on Twitter @julieburkhart. |
Increasing Access to Surgical Services for the Poor in Rural Haiti: Surgery as a Public Good for Public Health Although surgical care has not been seen as a priority in the international public health community, surgical disease constitutes a significant portion of the global burden of disease and must urgently be addressed. The experience of the nongovernmental organizations Partners In Health (PIH) and Zanmi Lasante (ZL) in Haiti demonstrates the potential for success of a surgical program in a rural, resource-poor area when services are provided through the public sector, integrated with primary health care services, and provided free of charge to patients who cannot pay. Providing surgical care in resource-constrained settings is an issue of global health equity and must be featured in national and international discussions on the improvement of global health. There are numerous training, funding, and programmatic considerations, several of which are raised by considering the data from Haiti presented here. must be featured in national and international discussions on the improvement of global health. There are numerous training, funding, and programmatic considerations, several of which are raised by considering the data from Haiti presented here. Introduction: a coordinated and robust response to the global burden of surgical disease The burden of surgical disease in the developing world, reflecting a multitude of infectious, noninfectious, and injury-related pathologies, has received inadequate attention to date. Among the world's poorest, a single procedure-amputation-is frequently the definitive therapy for a variety of unrelated processes such as trauma, infection, or gangrene ; many die without any care at all. It is increasingly evident that access to surgical services must be rapidly scaled up-in tandem with the development of primary health care infrastructure and programs for maternal and child health and for infectious diseases-to reduce the global burden of disease. Surgical services in Haiti Haiti is the poorest country in the Western Hemisphere and is faced, not coincidentally, with the worst health and human development statistics in the region. Inadequate infrastructure and ongoing political instability contribute to high maternal and infant mortality and an average life expectancy of just 53 years. There are three settings in which surgical care is delivered in Haiti. Private hospitals serve major metropolitan areas but have fees that are beyond the reach of the majority of the population. Public hospitals provide surgical care for a smaller fee, but supplies (sutures, medications, intravenous fluids, blood, and even gloves) must be purchased-frequently off-site, at private pharmacies-by the patient before any procedures take place. Charitable organizations are the third category of surgical care providers, but most of these institutions also charge fees for their services. The parallel existence of these three sources of surgical care is typical of most poor countries and, because of attendant fees, does not allow for adequate access to surgical care for the destitute sick-often the very people most in need of services. Among the multitude of nongovernmental organizations operating in rural Haiti, to our knowledge only one, Zanmi Lasante (ZL), provides a permanent setting in which a wide variety of surgical diseases can be addressed free of charge to the patient. This article describes Zanmi Lasante's experience scaling up surgical services over a 20-year period in a rural, isolated, and resource-poor setting. Zanmi Lasante: the birth of a ''pro-poor'' hospital and expansion in the public sector The Boston-based nonprofit organization Partners In Health (PIH) was founded in 1987 to support community health care efforts launched by ZL in a squatter settlement in central Haiti in 1983. The hillside site of Cange, originally in the midst of a community displaced by the flooding of a fertile valley for the construction of a hydroelectric dam, is about three hours from the capital city, Port-au-Prince, on a largely unpaved and sometimes impassible road. Since its inception, the medical facility at Cange has grown from a small community clinic to a large sociomedical complex registering more than 250,000 visits annually. Today, l'Hpital Bon Sauveur in Cange is a 104-bed, full-service hospital with two operating rooms; adult, pediatric, and surgical inpatient wards; an outpatient clinic; an infectious disease unit, which includes the national referral center for the treatment of multidrug-resistant tuberculosis (MDR TB); subspecialty services, including women's health, dental, and ophthalmology clinics; laboratories; pharmacies; a blood bank; radiology services; and a broad range of socioeconomic initiatives. The hospital is linked to a network of hospitals and health centers serving the population of Haiti's Central and Artibonite Departments, with a combined population of about 1.2 million people. A critical component of ZL's growth in this challenging setting is the recruitment and training of community health workers, called accompagnateurs. Today, 2,000 paid accompagnateurs serve as the vital link between ZL's health facilities and patients dispersed across the rural countryside. Their role in the PIH/ZL model of care, particularly for patients living with HIV or tuberculosis, has been discussed in detail in previous publications. A second element of ZL's growth in Haiti is its engagement with the public health sector to expand access to services. Since 2001, ZL has collaborated with the Haitian Ministry of Health to revitalize and reinforce eight public hospitals and clinics in central Haiti, from rebuilding hospitals to installing generators for electricity, to hiring and training staff, to establishing pharmaceutical supply chains. The explicit goal of this public-private partnership was to leverage funds for AIDS and tuberculosis programs, which became available in 2002, to reinforce comprehensive primary health care and to strengthen health systems in general. Users' fees, even within the public sector, remained a barrier for the poorest patients until it was agreed that HIV prevention and care, women's health, TB diagnosis and care, and diagnosis and treatment of all sexually transmitted infections would be considered ''public goods for public health''-provided free of charge to the patient. A major consideration for this partnership was the nearly complete absence of surgical services in central Haiti. Could surgical services be considered public goods for public health? Surgical services at l'Hpital Bon Sauveur Although minor procedures, from draining abscesses to tubal ligations, were done intermittently ever since clinical services were first offered in Cange, it was not until 1993 that an operating room was built. With the arrival of a fulltime obstetrician-gynecologist, over the next several years the OR was used regularly to address obstetrical emergencies. Short-term medical missions from the United States became increasingly surgical over time, but there were neither general surgeons nor anesthesiologists on staff. As the number of patients seeking care for the major morbidities of TB, HIV, diarrheal disease, and chronic noncommunicable diseases grew, more and more patients with surgical disease also came to l'Hpital Bon Sauveur seeking care. By the late 1990s, there was increased recognition of the need to treat a variety of routine, urgent, and emergent surgical diseases. To meet these needs, ZL built a second OR and a 15-bed surgical ward, and between 2000 and 2002 hired a general surgeon as well as two additional obstetrician-gynecologists. Through an agreement with the Cuban Ministry of Health, another general surgeon came to the hospital in 2002. An ophthalmologist was hired in 2003 and, with the help of the Haitian Red Cross, a proper blood bank was installed. By 2005, ZL's public-private partnerships at small regional hospitals and clinics, along with hundreds of attendant community health workers, served as a network referring patients from across the entire Central Plateau to l'Hpital Bon Sauveur for evaluation and surgery. Staff at all of the expansion sites are trained in basic surgical resuscitation and stabilization, and referrals are facilitated by Zanmi Lasante/Ministry of Health-owned ambulances in emergency cases or through the provision of transportation stipends to patients with nonurgent problems. Operating rooms at two of the largest expansion sites, Hinche and Belladres, have recently been refurbished and staffed with a full-time obstetrician and nurse anesthetist (NA) for emergency obstetrical care. A Mdecins Sans Frontires (MSF)-led NA training program began at l'Hpital Bon Sauveur in 2006; six nurses from ZL and other parts of Haiti are currently enrolled. To better understand the volume and variety of surgical procedures at l'Hpital Bon Sauveur, we undertook a retrospective review of the surgical cases performed between January 2002 and September 2005. We reviewed the operating room logs maintained by the surgical and anesthesia staff for patient age, place of residence, date of procedure, type of procedure, and the specialty involved. Distance traveled to the hospital was estimated as the crow flies based on patients' place of residence. Table 1 displays the characteristics of surgical patients served at l'Hpital Bon Sauveur between January 2002 and September 2005. A total of 2,601 patients underwent 2,900 procedures, ranging from simple incision and drainage to complicated cardiothoracic surgeries. Two notable findings confirmed our experiential understanding of the l'Hpital Bon Sauveur surgical program. First, the total number of patients seeking services has increased significantly, from 241 patients in 2002 to 762 during the first nine months of 2005. Second, the geographic distribution of patients has expanded: in 2002, more than 80% of patients lived within 50 km of the hospital. By 2005, however, more than half the patients traveled over 50 km to Cange for care-a significant journey to a rural, remote area of the country. This expanding catchment area points to the significance of PIH/ZL's accompagnateur model, which allows patients who might otherwise not seek care to be identified and referred from their communities and later followed up in their homes as necessary, but also the importance of providing free care to those who need it. By 2005 a third of all patients undergoing surgery at l'Hpital Bon Sauveur reported their place of residence to be the capital city of Port-au-Prince-the site of the largest public hospital in the country as well as numerous private surgical practices, all of which require fees for services. The widening geographic distribution of the ZL patient base over time presents convincing evidence of the surgical service's importance not just to the Central Plateau region, where the hospital is located, but to the country as a whole, as cost and/ or quality of care are prohibitive factors even when other facilities are available. A wide variety of surgical pathology was addressed at l'Hpital Bon Sauveur, with common procedures dominating the census (Table 2). General surgery accounted for almost half (47.6%) of all cases, obstetrical and gynecological cases a third (32.6%) of all cases, and urologic, Over the years, PIH and ZL have drawn on both the public health and human rights paradigms to help build and keep afloat a surgical program in a setting in which fee-forservice models are doomed to fail. Outside assessments and some members of the ZL staff suggested that certain surgical services could be provided on a sliding payment scale, but even a cursory study of this approach led us to conclude that triaging patients' ability to pay would have required significant resources and yielded little. It would have cost more to perform such means tests than could be recovered through patient fees. For the destitute sick, the great majority of our patients, the only hope for access to such services came from operationalizing the notion of health care as a human right and maintaining free access to surgical services as we do for medical services. Efforts to keep afloat ZL's rights-based surgical program proved taxing; by 2003, ZL was seeing patients from around the country, the costs of the program continued to rise, and no foundations or international funding mechanisms existed to support the provision of surgical services-even emergency obstetrics-to the very poorest. The connection between women's health and surgical care may well help us to move forward the general surgical agenda in resourced-constrained settings, as we argue in an accompanying editorial. Because there is a strong focus on women's health in both primary care and HIV services at Zanmi Lasante, it is no surprise that women also constitute the majority (55%) of surgical patients in this review. Although there is to date little enthusiasm for the notion of a right to surgical care, there is a growing movement to promote safe childbirth as a right-a possible entry point for promoting a broader agenda for surgical care in resource-poor settings. Many challenges remain for ZL to be able to fully address the burden of surgical disease in the Central Plateau and beyond. These challenges are shared in other similarly poor and rural areas worldwide: inadequate basic infrastructure, lack of trained health-care workers, and lack of large-scale, sustained funding for surgical services. This last issue-the question of consistent funding sources-is one of utmost importance. The logistics and capital costs of setting up a surgical theater are not trivial. Appropriate space, blood-banking, well-trained surgical and postoperative staff, proper tools and supplies, stable electricity, and accessible telecommunications are all essential for high-quality care. The World Bank, among others, has suggested that surgical services incorporated into hospital-level care may be as costeffective as otherlarge-scale public health initiatives. However, large public health initiatives and funders often lack the flexibility and long-term mandate to support the construction of surgical theaters or the regular procurement of consumables, let alone the provision of free care to patients who are unable to afford user fees. Staffing is a second major challenge. The World Health Organization (WHO) estimates that more than four million workers are needed worldwide to meet health-care needs, with sub-Saharan Africa and parts of Asia the most understaffed. The dearth of health personnel is even more striking in specialty fields. Shortages in surgical staffing include anesthesiologists, specialist and general surgeons, and nurses trained in postoperative or intensive care. The ''brain drain'' of workers from low-income to higher-income settings contributes to staffing gaps. The AIDS epidemic and its attendant psychological burdens have demoralized health professionals and even further reduced their numbers. Alongside an absolute shortage of health-care workers, the distribution of existing personnel between capital cities and rural areas is severely imbalanced, and encouraging health personnel to live and work in rural areas can be difficult. In addition to providing sufficient remuneration, ongoing training, and career-development opportunities, ZL has succeeded in retaining surgical staff in part because of the powerful motivator of providing health-care workers with the tools they need to perform their trade-namely, medicines, supplies, and adequate facilities. Targeted, local training efforts can also help overcome staffing shortages. At l'Hpital Bon Sauveur, the chief of anesthesia is a nurse anesthetist from the area who was one of 19 NAs trained by Mdecins Sans Frontires in Haiti between 1998 and 2002. Unfortunately, very few of these graduates are working in the public sector in Haiti; many are not working as NAs at all. In some cases, visiting staff can effectively supplement in-house capacity. Well-organized, short-term surgical missions can address complicated surgical issues if highquality follow-up care and services are available after the visiting surgeons leave. Developing residency training programs for U.S. surgeons based in resource-poor settings is one way to accomplish this. We have done this for medical residency ; now we need to do it for surgery. In extreme cases, some surgical patients with conditions that cannot be addressed in situ in Haiti have required intervention in the United States. PIH's Right to Health Care program serves patients with life-threatening medical and surgical needs that cannot be met at l'Hpital Bon Sauveur or other hospitals in Haiti. Recent interventions have included surgery for repair of tetralogy of Fallot and rheumatic mitral valve disease, total hip replacement, neurosurgery for excision of meningioma, nephrectomy, and plastic surgery management of severe burns. Conclusion Surgical disease has been neglected as a serious public health problem despite its major contribution to death and disability worldwide. Half a million women die of pregnancy-related causes every year; leading causes such as hemorrhage and obstructed labor have effective surgical interventions that are simply not available to those who need them most. Annually, more than one million people lose their lives to road traffic accidents, and 875,000 children and adolescents die as a result of injuries such as burns and falls ; these pathologies all have surgical therapies that can save lives or prevent disability. Recently there has been increasing acknowledgment of the importance of surgical care in public health. In 2005, the WHO established the Global Initiative for Emergency and Essential Surgical Care (GIEESC) with the aim of improving collaborations among organizations and agencies involved in reducing morbidity and mortality from surgical conditions. Further discussions have appeared recently in both medical and surgical journals, and the second edition of the World Bank's influential Disease Control Priorities in Developing Countries included a chapter on surgery. The Bellagio Conference in June 2007 brought together leaders in surgery, anesthesia, obstetrics, health policy, and health economics from Africa, Europe, and the United States, who collectively concluded that a significant proportion of the global burden of disease is surgical, that with investments in infrastructure and training a majority of surgical disease can be treated or prevented at first-level referral centers, and that the integration of surgical services with primary health care services will be essential for prevention and referral efforts. Zanmi Lasante's experience providing surgical services in impoverished rural Haiti suggests that these recommendations are urgent and actionable. Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. |
The Centre on Wednesday extended the Armed Forces (Special Powers) Act to three districts in Arunachal Pradesh, declaring them as 'disturbed area'.
The Centre on Wednesday extended the Armed Forces (Special Powers) Act to three districts in Arunachal Pradesh, declaring them as ‘disturbed area’. The Ministry of Home Affairs (MHA) notified that the central government in exercise of the powers conferred by Section 3 of the Armed Forces (Special Powers) Act, 1958 (28 of 1958) had declared the Tirap, Changlang and Longding districts of Arunachal Pradesh and the area falling within the jurisdiction of eight police stations in the districts of Arunachal Pradesh bordering Assam as “disturbed”areas.
“Now, therefore, Tirap, Changlang and Longding districts in Arunachal Pradesh and the areas falling within the jurisdiction of the following eight police stations in the districts of Arunachal Pradesh, bordering the State of Assam, are declared as ‘disturbed area’ under Section 3 of the Armed Forces (Special Powers) Act, 1958 up March 31, 2019 w.e.f. October 1, 2018, unless withdrawn earlier,” the notification further said.
The police stations are Balemu and Bhalukpong stations in West Kameng district, Seijosa police station in East Kameng district, Balijan police station in Papumpare district, Namsai and Mahadevpur police stations in Namsai district, Roing police station in Lower Dibang Valley district and Sunpura police station in Lohit district.
On August 30, Assam Governor Jagdish Mukhi extended the AFSPA in the state for the next six months. The AFSPA grants special powers to the Indian Armed Forces in ‘disturbed areas’. According to The Disturbed Areas (Special Courts) Act, 1976, once declared ‘disturbed’, the area has to maintain the status quo for a minimum of three months. |
Multi Objective Optimization of Parameters of Torsional Vibration Dampers Considering Damping Effect and Light Weight Design To reduce the torsional vibration of vehicle power transmission system (VPTS), a torsional vibration model with multiple degrees of freedom (MDOF) of VPTS was established. The scheme of equipping torsional vibration dampers (TVDs) on the drive shaft was employed by the calculation of the forced vibration and the free vibration of the VPTS. The energy method was used to optimize the parameters of single-stage, two-stage parallel, and two-stage series TVDs based on the principle that balances the damping effect and lightweight design. On the basis of this, the parameters of the models incorporating TVD and elastic couplings (ECs) were optimized. Results showed that the proposed method can ensure the damping effects of TVD and realize the lightweight. |
Spenser's "Amyntas": Three Poems by Ferdinando Stanley, Lord Strange, Fifth Earl of Derby Spenser devoted twelve lines of Colin Clouts Come Home Againe to a lament for "Amyntas": "... the noblest swaine / That ever piped in an oaten quill: / Both did he other which could pipe maintaine, / And eke could pipe himselfe with passing skill" (lines 440-43). Modern scholars have consistently identified Amyntas with Ferdinando Stanley, Lord Strange from 1572 to September 25, 1593 and Earl of Derby from the latter date until his death, April 16, 1594.1 Stanley's artistic patronage is best seen in his maintenance, from at least 1576 until his death, of a company of actors with which Shakespeare may have been associated.2 His contemporary reputation as a poet is supported beyond Spenser's claim by the appearance of his name in the list of "noble personages" whose works are supposedly represented in Belvedere, or, The Garden of the Muses (1600, sig. A5); here Stanley is listed with such better-known Elizabethan court poets as Oxford, Ralegh, and Dyer. To date, however, our only tangible proof that Stanley ever "piped in an oaten quill" has been the poem ascribed to him in a manuscript owned by Sir John Hawkins, who submitted the text to The Antiquarian Repertory (3 : 133-38).3 On the merits of this verse, Alexander C. Judson concluded that Stanley indeed "was a poet (though no poem of consequence by him is known today)."4 In what follows, I hope to bulwark Spenser's praise of Stanley by showing, first, that the Hawkins text is more consequential than Judson believed and, second, that it does not fully represent Stanley's muse, to judge from two heretofore unpublished poems, attributed to him in Cambridge MS Dd.5.75, fol. 32v and Bodleian MS Rawlinson Poetry 85, fols. 76v-77r. The title of the Hawkins text, "A SONNETT by FERDINANDO EARLE of DERBY," indicates a date of transcription after September 25, 1593, when Stanley succeeded to his father's title." The poem's aimless narrative and absurd style point, I believe, not to the author's incompetence, but to his conscious burlesque of the unlearned and homely pastoral stance. This burlesque was not aimed at the inverted syntax and archaic diction of Spenser's pastorals but, more probably, at the redundant style of such works as Abraham Fraunce's The Lamentations of Amyntas for the Death of Phillis, or the celebration of rustic amours in Breton's "Sweet Phillis if a sillie Swaine," or "A Sillie Shepheard lately sate," from Brittons Bowre of Delights (1591, sig. F4-4v, G1v-2). Breton's own lyric, beginning "Fair in a morn (o fairest morn / was never morn so fair),''6 parodies these same forms in a manner quite similar to Stanley's in the Hawkins text. Both poems are written primarily in ballad stanza and concern a shepherd's futile love for a shepherdess named Phyllis. Both achieve their effect through the exaggerated use of the same rhetorical devices: 1 See Ronald B. McKerrow, The Works of Thomas Nashe, 4:150-51; Alexander C. Judson, The Life of Edmund Spenser, p. 6; Kelsie Harder, "Nashe's Rebuke of Spenser," Notes and Queries 198 : 145. 2 John Tucker Murray, English Dramatic Companies (1910; repr. New York, 1963), 1:75; E. K. Chambers, Elizabethan Stage, 2:118-26. 3 Ed. Francis Grose and Thomas Astle, 4 vols. (London, 1775-84), reprinted 1807-9. The Stanley verse was reprinted from the first edition in Thomas Park's enlarged revision of Walpole's A Catalogue of the Royal and Noble Authors of England, Scotland, and Ireland, 5 vols., 2:46-51. 4 Judson, p. 5. 5 I have been unable to trace Hawkins's manuscript, which was probably destroyed in the fire which gutted his house in Westminster, along with his "valuable collection of books and prints," in 1785 (Percy A. Scholes, The Life and Activities of Sir John Hawkins , p. 157). 6 Printed in Englands Helicon, sig. G4-5; manuscript versions in Bodleian MS Rawlinson Poetry 85, fols. lv-2r, and British Museum Additional MS 34,064, fols. 17v-18r. |
Effect of dual-stage actuator on positioning accuracy in 10 k rpm magnetic disk drives We have developed a piezoelectric micro-actuator for dual-stage actuator systems in magnetic disk drives. This microactuator, which drives the head suspension assembly, is based on the shear deformation of piezoelectric elements. We installed the microactuator in one of Fujitsu's 3.5-inch commercial drives for evaluation of the servo system of dual-stage actuator. This paper describes the effect of the dual-stage servo system on positioning accuracy compared with the single actuator. |
1. Field of the Invention
The present invention relates to a magnetic sensor system including a magnetic field generation unit for generating a magnetic field to be detected and a magnetic sensor for detecting the magnetic field.
2. Description of the Related Art
In recent years, magnetic sensors have been widely used to detect the rotational position of an object in a variety of applications such as detection of the degree of opening of a throttle valve in automobiles, detection of the rotational position of steering in automobiles, and detection of the rotational position of the wiper of automobiles. Magnetic sensors are used not only to detect the rotational position of an object but also to detect a linear displacement of an object. Systems using magnetic sensors are typically provided with means (for example, a magnet) for generating a magnetic field to be detected whose direction rotates in conjunction with the rotation or linear movement of an object. Hereinafter, the magnetic field to be detected will be referred to as the target magnetic field. The magnetic sensors use magnetic detection elements to detect the angle that the direction of the target magnetic field in a reference position forms with respect to a reference direction. The rotational position or linear displacement of an object is thus detected.
Among known magnetic sensors is one that employs a spin-valve magnetoresistive (MR) element as the magnetic detection element, as disclosed in WO 00/17666, U.S. Pat. No. 7,483,295 B2, U.S. Pat. No. 7,394,248 B1, and U.S. Pat. No. 8,054,067 B2. The spin-valve MR element has a magnetization pinned layer whose magnetization direction is pinned, a free layer whose magnetization direction varies according to the direction of the target magnetic field, and a nonmagnetic layer disposed between the magnetization pinned layer and the free layer.
A magnetic sensor that employs a spin-valve MR element as the magnetic detection element may have an error in a detected angle due to variations in the magnetic properties of the MR element, as described in U.S. Pat. No. 8,054,067 B2. U.S. Pat. No. 8,054,067 B2 discloses a technology for reducing an error in the detected angle caused by manufacturing variations in MR elements. This technology is, so to speak, a technology for reducing an error in the detected angle that will be found at the time of completion of the magnetic sensor as a product.
Errors in the detected angle that could occur in the magnetic sensor include an error that emerges after the installation of the magnetic sensor in addition to an error found at the time of completion of the product as mentioned above. One of the causes by which an error in the detected angle emerges after the installation of the magnetic sensor is an induced magnetic anisotropy that occurs on an a posteriori basis in the free layer of the MR element. Such an induced magnetic anisotropy may occur in the free layer when, for example, the temperature of the MR element is lowered from a high temperature while an external magnetic field is being applied to the MR element in a particular direction. Such a situation may occur when, for example, the magnetic sensor is installed in an automobile and a specific positional relationship is established between the magnetic sensor and means for generating a target magnetic field during non-operation of the automobile. More specifically, the aforementioned situation may occur when the magnetic sensor is used to detect the position of an object that comes to a standstill in a predetermined position during non-operation of the automobile, such as the wiper of an automobile.
The magnetic sensor is required to have a reduced error in the detected angle that may emerge due to an induced magnetic anisotropy occurring on an a posteriori basis after the installation. Note that the foregoing descriptions have dealt with the problem that is encountered when an induced magnetic anisotropy occurs on an a posteriori basis in the free layer of a spin-valve MR element after the installation of a magnetic sensor that employs the spin-valve MR element as the magnetic detection element. However, this problem applies to any cases where the magnetic sensor has a magnetic detection element that includes a magnetic layer whose magnetization direction varies according to the direction of the target magnetic field and an induced magnetic anisotropy occurs on an a posteriori basis in the magnetic layer of the magnetic detection element after the installation of the magnetic sensor. |
Preparation and Characterization of FeCo2O4 Nanoparticles: A Robust and Reusable Nanocatalyst for the Synthesis of 3,4-Dihydropyrimidin- 2(1H)-thiones and Thiazolopyrimidines The present research describes a mild and efficient method for the synthesis of 3,4-dihydropyrimidine-2(1H)-thiones and thiazolopyrimidine via multi-component reactions using FeCo2O4 nanoparticles. It was found that FeCo2O4 nanoparticles act as a powerful and effective catalyst. The prepared catalyst was characterized by the various spectroscopic techniques.The three-component reaction of thiourea, aromatic aldehydes and ethyl acetoacetate was catalyzed by FeCo2O4 nanoparticles. Next, the prepared 3,4-dihydropyrimidin-2(1H)-thiones were applied for the preparation of thiazolopyrimidines via the reactions of 3,4-dihydropyrimidine-2(1H)- thiones, chloroacetic acid, and aromatic aldehydes in the presence of FeCo2O4 nanoparticles.The FeCo2O4 nanoparticles were synthesized by a facile one-step method and the structure determination of the catalyst has been done using spectral techniques.Then, the prepared nanocatalyst was used in the synthesis of 3,4-dihydropyrimidin-2(1H)-thiones and thiazolopyrimidines under solvent-free conditions at 80°C.FeCo2O4 nanoparticles as a magnetic nanocatalyst were applied as a catalyst in the synthesis of some heterocyclic compounds in excellent yields and short reaction times. The average particle size of the catalyst is found to be 30-40 nm. The study on the reusability of the FeCo2O4 nanoparticles showed the recovered catalyst could be reused fifth consecutive times. We propose that FeCo2O4 nanoparticles act as a Lewis acid cause to increase electrophilicity of carbonyl groups of substrates and intermediates to promote the reactions.The present research introduced various advantageous including excellent yields, short reaction times, simple workup procedure and recyclability of the FeCo2O4 NPs in order to the synthesis of 3,4-dihydropyrimidin-2(1H)-thiones and thiazolopyrimidines. |
YORK, Pa. — Saniya Chong is a much watch.
When the 5-foot-9 Ossining point guard is on the court, the fans lucky enough to be in attendance get to see one of the nation’s best players – a dynamo in every sense of the word. Off of it, college coaches and fans wait patiently to see where the rising senior will take her talents next season.
Over the weekend she played with Ossining coach Dan Ricci with the Hudson River Breeze at the Blue Chip USA Invitational at the Toyota Arena in York, Pa. Chong quickly became the talk of the tournament. She averaged 46.6 points per contest over five games as her team went 4-1 in the Platinum bracket. That includes a 53-point performance against the Pittsburgh Rockers in front of UConn head coach Geno Auriema, a memorable effort in which she also has 10 rebounds and five steals.
“When I tell her one of the coaches is here, she seems to perk up,” Ricci said.
The Bronx native has trimmed her list of suitors down to just four – UConn, Maryland, Ohio State and Louisville – after eliminating North Carolina and Miami. Because of its close proximity, Chong has already taken an unofficial visit to UConn, which she called a “wonderful place.” She plans to begin scheduling official stops in September.
A lot has changed for the reserved Chong in just a year’s time, when her only offers were Virginia Tech and Ohio State, and she was unranked by most scouting services.
There are detractors, of course. There are those who believe Chong is overrated because her Ossining team doesn’t play high profile enough teams. She plays her travel ball with the Westchester Hoopers and the Breeze, not more well-known squads like Exodus, the Gauchos or the Philly Belles. Her gaudy stats, the doubters contend, are coming against teams who can’t physically match up with the long, quick and athletic lead guard.
Chong averaged 33.3 points, 9.7 assists, 5.2 rebounds and 5.0 steals as Ossining went 23-1 and reached the NYPHSAA Class AA state semifinals last season. It’s lone loss came to eventual state Federation champion Cicero-North Syracuse and Breanna Stewart as Chong scored 21 points. The more than 2,000-point scorer was invited to tryout for the USA U17 national team and also dropped in 54 points, including eight 3-pointers, in a win over Archbishop Molloy at the Francis Lewis Winter Ball.
That’s the reason why Chong has some of the nation’s best college programs to choose from and will end her career as one of New York State’s top all-time leading scores. Ricci doesn’t believe she can make a wrong choice. He just wants her to make the best one. |
Turkish president holds the Netherlands responsible for massacre of 8,000 Bosnian Muslims as row over rallies deepens
The Turkish president, Recep Tayyip Erdoğan, has held the Netherlands responsible for the worst genocide in Europe since the second world war as the row over Turkish ministers addressing pro-Erdoğan rallies in the country deepened.
In a speech televised live on Tuesday, Erdoğan said: “We know the Netherlands and the Dutch from the Srebrenica massacre. We know how rotten their character is from their massacre of 8,000 Bosnians there.”
Erdoğan stakes all on winning referendum as diplomatic row simmers Read more
The comments followed Turkey’s suspension of diplomatic relations with the Netherlands on Monday and Erdoğan twice describing the Dutch government as Nazis on Saturday after his foreign minister and family affairs minister were prevented from attending rallies.
The Dutch prime minister, Mark Rutte, faces a general election on Wednesday in which the far-right leader, Geert Wilders, could win the largest number of seats. Rutte earlier on Tuesday played down the impact of Turkey’s diplomatic sanctions, which he said were “not too bad” but were inappropriate as the Netherlands had more to be angry about.
However, after Erdoğan’s speech Rutte told the Dutch TV channel RTL Nieuws that Erdoğan “continues to escalate the situation”, adding the Srebrenica claim was “a repugnant historical falsehood”.
“Erdoğan’s tone is getting more and more hysterical, not only against The Netherlands, but also against Germany,” he said. “We won’t sink to that level and now we’re being confronted with an idiotic fact ... It’s totally unacceptable.”
Facebook Twitter Pinterest The Dutch prime minister, Mark Rutte: ‘Erdoğan’s tone is getting more and more hysterical.’ Photograph: Dylan Martinez/Reuters
Turkey is holding a referendum on 16 April on extending Erdoğan’s presidential powers where the votes of Turkish citizens in EU countries will be crucial.
Erdoğan’s decision to use the Srebrenica genocide, for which a previous Dutch government resigned over its failure to prevent, as a further attack on the Netherlands showed that Ankara does not intend to back down from the dispute.
A lightly armed force of 110 Dutch UN peacekeepers failed to prevent a Bosnian Serb force commanded by Gen Ratko Mladić entering what had been designated a safe haven on 11 July 1995. Muslim men and boys were rounded up, executed and pushed into mass graves.
The former Bosnian Serb leader Radovan Karadžić was found guilty of genocide over the massacre by the UN tribunal in March 2016 and sentenced to 40 years in jail.
Erdoğan said in his speech he would not accept an apology from the Netherlands over the treatment of the ministers and suggested that further action could be taken.
He accused the German chancellor, Angela Merkel, of attacking Turkey the same way that Dutch police used dogs and water cannon to disperse protesters outside the Turkish consulate in Rotterdam. Erdoğan said Merkel was “no different from the Netherlands”, and urged emigre Turks not to vote for “the government and the racists” in upcoming European elections.
What happened in the Turkish referendum and why does it matter? On 16 April 2017 Turkish voters narrowly approved a package of constitutional amendments granting Recep Tayyip Erdoğan sweeping new powers. The amendments will transform the country from a parliamentary democracy into a presidential system – arguably the most significant political development since the Turkish republic was declared in 1923. Under the new system – which is not due to take affect until after elections in June – Erdoğan will be able to stand in two more election cycles, meaning he could govern until 2029. The new laws will notionally allow Erdoğan to hire and fire judges and prosecutors, appoint a cabinet, abolish the post of prime minister, limit parliament’s role to amend legislation and much more. The president's supporters say the new system will make Turkey safer and stronger. Opponents fear it will usher in an era of authoritarian rule.
Erdoğan had on Monday defied pleas from Brussels to tone down his rhetoric, repeating accusations of European “nazism” and saying his ministers would take their treatment by the Dutch to the European court of human rights.
The Turkish foreign ministry said in a statement on Tuesday that the EU’s stance on Turkey was short-sighted and “carried no value” for Turkey. It said the EU had “ignored the violation of diplomatic conventions and the law”.
The Netherlands, Austria, Germany, Denmark and Switzerland, all of which have large Turkish immigrant communities, have cited security and other concerns as reasons not to allow Turkish officials to campaign in their countries in favour of a referendum vote. But with as many as 1.4 million Turkish voters in Germany alone, Erdoğan cannot afford to ignore the foreign electorate.
Austria’s chancellor, Christian Kern, called on Monday for an EU-wide ban on Turkish rallies, saying it would take pressure off individual countries. But Merkel’s chief of staff, Peter Altmaier, said he had doubts as to whether the bloc should collectively decide on a rally ban.
Analysts said the Turkish president was using the crisis to show voters that his strong leadership was needed against a Europe he routinely presents as hostile.
Erdoğan was “looking for ‘imagined’ foreign enemies to boost his nationalist base in the run-up to the referendum”, said Soner Çağaptay, the director of the Turkish research programme at the Washington Institute.
Marc Pierini, a former EU envoy to Turkey, said he saw no immediate solution to the crisis. “The referendum outcome in Turkey is very tight and the leadership will do everything to ramp up the nationalist narrative to garner more votes,” he said.
The standoff has further strained relations already frayed over human rights, while repeated indications from Erdoğan that he could personally try to address rallies in EU countries risk further inflaming the situation.
The row looks likely to dim further Turkey’s prospects of joining the EU, a process that has been under way for more than 50 years. “The formal end of accession negotiations with Turkey now looks inevitable,” the German commentator Daniel Brössler wrote in Süddeutsche Zeitung. |
Stability of Mn2RuxGa-based Multilayer Stacks Perpendicular heterostructures based on a ferrimagnetic Mn2RuxGa (MRG) layer and a ferromagnetic Co/Pt multilayer were examined to understand the effects of different spacer layers (V, Mo, Hf, HfOx and TiN) on the interfaces with the magnetic electrodes, after annealing at 350 C. Loss of perpendicular anisotropy in MRG is strongly correlated with a reduction in the substrate-induced tetragonality due to relaxation of the crystal structure. In the absence of diffusion, strain and chemical ordering within MRG are correlated. The limited solubility of both Hf and Mo in MRG is a source of additional valence electrons, which results in an increase in compensation temperature Tcomp. This also stabilises perpendicular anisotropy, compensating for changes in strain and defect density. The reduction in squareness of the MRG hysteresis loop measured by anomalous Hall effect is<10 %, making it useful in active devices. Furthermore, a CoPt3 phase with (2 2 0) texture in the perpendicular Co/Pt free layer promoted by a Mo spacer layer is the only one that retains its perpendicular anisotropy on annealing. Introduction Modern spintronic materials are being developed for high-speed, non-volatile data storage products such as magnetic random-access memory. An ideal material would be one which has high spin-polarisation, yet little or no magnetic moment. Mn 2 Ru x Ga (MRG) is a ferrimagnetic inverse Heusler alloy, having an XA structure with two inequivalent antiferromagnetically aligned Mn sublattices and almost complete filling of the four lattice sites, as shown in Figure 1. It is considered to be a zero-moment half-metal (ZHM) when its net moment vanishes at the compensation temperature, T comp, and it is a potential candidate for spintronic applications owing to its immunity to magnetic fields, reasonably high Curie temperature and large perpendicular anisotropy field close to compensation. The possibility of tunable anti-ferromagnetic oscillation modes in the THz region is key for future applications in high-frequency computing and communications, and has already been observed in the similar Mn 3−x Ga materials. Perpendicular magnetic anisotropy (PMA) due to biaxial strain is observed in films grown on MgO. The ruthenium 4d site occupancy allows the magnetic properties to be tuned according to the application; in particular, T comp increases with increasing Ru concentration and valence electron count, n v, in the unit cell. Annealing of magnetoresistive devices can have varying outcomes -the crystallisation of the MgO/CoFeB bilayer results in a dramatic increase of tunnelling magne- Figure 1: Crystal structure of Mn 2 RuxGa is a distorted XA Heusler structure with two inequivalent, antiferromagnetically coupled sublattices, Mn 4a and Mn 4c, leading to zero moment at compensation toresistance (TMR) ratio due to coherent tunnelling and perpendicular anisotropy in the free layer, while the diffusion of Ta and other species into the active portion of the device can have a negative impact on functionality. This MgO/CoFeB electrode structure is currently the industry choice for TMR applications, and annealing temperatures for crystallisation of amorphous CoFeB into a body centered cubic structure typically occurs above 320°C, depending on boron content. The use of thin interlayers to enhance performance of MnGa-based magnetic tunnel junctions has proved effective. A major concern with Mn-based materials, however, is diffusion which can affect the both crystal structure as well as the quality of the spin-polariser/barrier interfaces. We have previously demonstrated that an ultrathin dusting layer of Ta or Al can be used to mitigate the effects of diffusion between MRG and an MgO tunnel barrier. Using this technique, a TMR of 40 % has been achieved at 10 K and at low bias in a MRG based magnetic tunnel junction using a CoFeB free layer. Similarly, we have shown that Hf can magnetically couple MRG and CoFeB thin films, after annealing at high temperatures. Hf and Al are not known for preventing diffusion, so the mechanism by which they act to maintain performance is not clear, compared to other similar diffusively mobile materials. A previous study of MRG, annealed at various temperatures up to 400°C and capped with AlO x, shows that the magnetic and crystalline properties are stable up to 350°C, beyond which the crystal structure relaxes. There are several types of defects that occur in the MRG lattice -Mn-Ga (4a/4c ↔ 4b), Mn-Ru (4a/4c ↔ 4d), and Ru-Ga (4d ↔ 4b) antisites -as well as excess Mn and Ga on 4d sites when x < 1. We can quickly identify Ru-based defects in X-ray crystallography due to the much stronger atomic scattering factor of Ru compared to Mn and Ga. Mn-Ga antisite defects have previously been identified as the source of additional electronic pressure that modifies the position of the Fermi level, increasing the moment and spin polarisation. Here we correlate magnetic and transport properties with the presence of crystalline defects. To investigate, we use a spin-valve structure of the form MgO//Mn 2 Ru 0. 7 Ga/X(t)/ 8 /Co(0.4)-/Pt where the spacer layer, X, has a thickness, t, of 1.4 nm and 2 nm (parenthetical values in nm). It will act as a barrier preventing diffusion, or as a source of mobile atoms. The stack uses a Co/Pt superlattice as the free layer due to its perpendicular anisotropy as deposited, independent of seed layer or annealing requirements as with a MgO/CoFeB free layer. The five materials selected as X in this study are listed in Table 1. TiN thin films are widely used as diffusion barriers and serve as a baseline comparison where we expect no diffusion. Hf has also been chosen to serve as a comparison due to our previous experience with it. Diffusion-driven defects are expected to result in a reduction of crystalline order in MRG. Any change in c/a ratio will change the magneto-crystalline anisotropy in MRG, while the perpendicular anisotropy in Co/Pt multilayers is primarily caused by interfacial anisotropy driven by spinorbit hybridisation of Co and Pt. This means that a change in the interfacial roughness or strain will have an impact on the Co/Pt magnetic properties. We measured crystallographic and magnetotransport characteristics before and after annealing at 350°C, a standard industrial practice for MgO/CoFeB-based devices. In this way we aimed to identify the influence of annealing the structure based on the interlayer material used, and its effect on the properties of both electrodes. Methods All films except TiN were deposited by direct current sputtering onto 10 mm 10 mm single crystal MgO (0 0 1) substrates in a SFI Shamrock sputter tool (base pressure <2.5 10 −6 Pa); TiN was deposited by radio frequency sputtering. MRG is deposited at 320°C by co-sputtering from a Mn 2 Ga target and a Ru target, both 76.2 mm diameter, at a target-substrate distance of 100 mm. Argon gas flow was 38 cm 3 min −1. All other materials were deposited at room temperature, except for two spacer layers of TiN grown at 320°C. HfO x was formed by natural oxidation of metallic Hf films in O 2 atmosphere at 2 Pa for 60 s. Annealing is carried out under vacuum at 350°C for 60 minutes in a perpendicular field of 800 mT. X-ray diffraction (XRD) and X-ray reflection (XRR) were measured with a Panalytical X'Pert tool using Cu K radiation, and magnetotransport data was collected by the Van der Pauw method in a 1 T GMW electromagnet. Crystallographic data were analysed following the method of by fitting a Voigt function to the peaks, taking into consideration K 2 and instrumental broadening, characterised using an Al 2 O 3 standard, NIST 1976b. Results As-deposited MRG is textured, with the crystallographic c-axis perpendicular to the substrate surface. Two diffraction peaks are observed in a symmetric -2 scan, namely the (0 0 2) and (0 0 4) ( Figure 2). In addition to the substrate and MRG peaks, we also note the Co/Pt superlattice (0 0 2) peak. As mentioned in section 1, the magnetic properties are strongly dependent on the crystal characteristics. We determine the out-of-plane lattice parameter c, crystal coherence length L c perpendicular to the film (using the Scherrer formula), the perpendicular strain, and the ratio of intensities of the two peaks S Pre-anneal Post-anneal Co/Pt Rem. Sat. Hall Voltage (mV) Pre-anneal Post-anneal signifying the Ru/Mn order as Ru occupying the 4a or 4b sites will increase the intensity of the (0 0 2) peak. Higher S (0 0 2)/(0 0 4) ratios indicates disorder. By comparison L c and give us a metric for the long-range disorder in the film, due to grain boundaries and stacking faults, where larger grain size or less strain indicates a more homogenous film. MRG has a coercivity in a perpendicular magnetic field that diverges as the temperature approaches T comp, where the anomalous Hall effect (AHE) signal changes sign. The composition of MRG used here, x = 0.7, was chosen to give T comp = 165 K, with an as-deposited coercivity of H c ≈ 380 mT at room temperature. Squareness of the Hall signal, i.e. the ratio of Hall voltage at saturation to that at remanence, is used an indicator of perpendicular anisotropy. The main parameters from the AHE hysteresis are labeled in Figure 3. The as-deposited MRG exhibits perpendicular magnetic anisotropy (PMA) in all cases, irrespective of spacer material or thickness; magnetic properties upon annealing are spacer material dependent. It is typically reported that perpendicular anisotropy in Co/Pt is accompanied by a (1 1 1) texture, however we note here that all asdeposited Co/Pt films exhibited perpendicular anisotropy regardless of initial texture or phases present. After annealing with a 1.4 nm Hf spacer, the Co/Pt layer loses much of its perpendicular anisotropy, indicated by the loss of squareness as demonstrated in to 0.99 nm in Pt. This reduces the interfacial anisotropy, bringing the moment in-plane, and is caused by intermixing as evidenced by the weak crystallisation of CoPt 3 with (1 1 1) texture after annealing, as seen in Figure 2. The Co and Pt interfaces of the free layer are well defined before annealing, as can be seen from XRR data for a hetereostructure with a 1.4 nm V spacer layer in Figure 4(a). A clear and intense Co/Pt (0 0 1) superlattice peak is visible which disappears upon annealing, shown in Figure 4(b), a result of intermixing and alloying between the layers forming a CoPt 3 phase as shown in Figure 2. XRD and roughness data for the Co/Pt multilayers is given in Table 3. Of interest is that in each case, the average Co roughness is approximately equivalent to the desired layer thickness (0.4 nm), indicating incomplete coverage. The anisotropy of MRG appears to be maintained, with minimal change in coercivity or squareness. Changes in Co/Pt properties are considered independent of changes in MRG. As discussed in Section 1, the magneto-crystalline anisotropy of MRG is largely dependent on the c/a ratio, or more specifically the tetragonal distortion of the cubic cell - c = (c − a)/a. The properties of MRG are highly dependent on the spacer layer used, and the relative change of each parameter in MRG after annealing has been collated in Figure 5. Below, we summarise the results for each spacer material. For reference, Table 2 gives a summary of the mean and standard deviation for the various properties measured in MRG before annealing. As a basic metric, we aim to main- Giant magnetoresistance was not measured in these devices as a current-perpendicular-to-plane geometry would be required to prevent shunting effects of currents through highly resistive layers, necessitating nanoscale lithographic patterning of the metallic films. Vanadium Annealing of a vanadium spacer stack results in large reductions of the MRG coercivity (∼ −90 %) and squareness (∼ −75 %), along with a significant (∼ −80 %) reduction in c. This indicates the anisotropy has a primarily in-plane contribution, though a small fraction of grains are still perpendicular. This is accom-panied by an extremely large (>500 %) increase of S, as well as a moderate decrease of L c and increase in indicating complete reordering of the crystal structure. Additional peaks near the MRG (0 0 2) and (0 0 4) peaks with d-spacing of ∼ 0.3058 nm and 0.1511 nm are present after annealing. These d-spacings correspond well to either RuV(1 0 0)(0.298 nm), RuV(2 0 0)(0.148 nm) or Ga 5 V 2 (2 2 0)(0.317 nm), Ga 5 V 2 (5 3 0)(0.1537 nm). Given the phase diagrams for Ga-V and Ru-V, we attribute this phase to a Ga-V binary such as Ga 5 V 2 or Ga 41 V 8, both of which are peritectics with relatively low decomposition temperatures. Based on the substantial increase in S, reordering of Ru from the Heusler 4d site occurs forming a highly disordered cubic alloy, with an A2 structure. There is a moderate CoPt 3 (1 1 1) and (2 0 0) texture before annealing. After annealing, only a strong CoPt 3 (2 0 0) peak is present, and magnetic anisotropy is also in-plane. In addition, the average roughness for Co increases moderately, while the roughness of the Pt layers approximately doubles in both cases. Titanium Nitride When using a TiN spacer, we observe a collapse in the tetragonality of MRG while L c increases and decreases, indicating that defects are being removed. This is accompanied by a loss of coercivity and squareness in the magnetic hysteresis. TiN is a well known diffusion barrier, and defects introduced by diffusion are not considered as the cause. We also see that there is no direct correlation with Ru-Mn disorder, as there are three cases with small increase in S contrasted by the 1.4 nm TiN grown at high temperature which has a lower S ratio. However, there is a correlation between strain and chemical ordering S. This means that defects such as stacking faults and grain boundaries induce strain on the crystal structure, which contributes strongly to the magneto-crystalline anisotropy of the film and has a more prominent effect than Ru-Mn anti-sites. The effect is independent of growth temperature. From the Co/Pt superlattice, we observe a very weak Pt(1 1 1) peak, which is distinct from the CoPt 3 (1 1 1), along with a strong CoPt 3 (2 0 0). The high intensity, as well as the Laue fringes observed around the peak indicates that the Pt(1 1 1) is due to the thick Pt capping layer, caused by relaxation at a critical thickness. The close lattice matching of TiN(1 0 0) to MRG(1 1 0) means the TiN(0 0 1) out-of-plane texture is expected, which helps to induce a CoPt 3 (2 0 0) phase in the Co/Pt. However, PMA is lost after annealing. Average roughness of Co and Pt increase moderately in all cases. Pt layers begin with a higher roughness in the case of high temperature grown TiN spacer layers. By comparison, the roughness after annealing is equal or greater when using room temperature grown TiN. This indicates that a high temperature grown TiN seed layer is less suitable, but is also more stable. Hafnium Oxide As HfO x is formed by natural oxidation of a Hf metal layer, there is a gradient of oxygen content that depends on the film thickness. MRG performs poorly with a 1.4 nm thick HfO x spacer resulting in near total loss of perpendicular anisotropy upon annealing, whereas with a 2 nm spacer it maintains both coercivity and squareness with reductions of 11 % and 14 % respectively, despite a significant increase in strain (∼ 25 %). This is correlated with a lesser reduction in c-spacing for the 2 nm spacer stack. Similarly to the case of TiN, the reduction in c comes despite an improvement in the coherence length. If the 1.4 nm HfO x is fully oxidised (x ∼ 2), then diffusion into MRG, either across the barrier or from the barrier itself, will be reduced. This will result in oxidation of MRG at the interface, however. The effect is then similar to that using TiN. As the HfO x films were treated for equal time, the thicker HfO x is not fully oxidised due to passivation, which leads to some interdiffusion. There is no observable texture in the Co/Pt superlattice before annealing. Weak CoPt 3 (1 1 1) and (2 0 0) texture is observed after annealing, but PMA is lost. As with the TiN layers, we see a moderate increase in Co and Pt roughness, with a higher as-deposited roughness. Hafnium Hf spacers work well, with the 1.4 nm spacer showing only a small change in all properties. In contrast to other materials, the 2 nm Hf spacer increases the c of the MRG unit cell. Furthermore, it raises T comp to a value slightly above RT, which causes H c to increase significantly due to its divergent nature close to T comp. The increase in c is accompanied by a decrease in L c and an increase in, indicating an increase of line and planar defects. According to the binary phase diagrams, Hf absorption into both Mn and Ga is limited to ∼ 1 at. % while maintaining crystal structure. This limited solubility accounts for the reduced effects seen in the HfO x 2 nm and Hf 1.4 nm based heterostructures, where the counter-diffusion into the Hf layer limits the available soluble material. We see different effects on the Co/Pt layer depending on the thickness of the Hf spacer, with the 1.4 nm thick spacer inducing no discernable texture in the superlattice. After annealing there is a weak CoPt 3 (1 1 1) texture. The 2 nm thick spacer promotes a CoPt 3 (1 1 1) orientation which is maintained after annealing, as well. In neither case is there any PMA after annealing, although there is a clear preferred orientation. The roughness of Co layers increases moderately. Annealing causes a substantial increase in roughness of Pt layers, to ∼ 1 nm, with the 2 nm Hf spacer giving a higher initial roughness. Molybdenum Mo spacers have similar properties to Hf spacers, and the phase diagrams show a greater affinity of Mn for Mo (4 at. %) and Ga (16 at. %) Counter-diffusion is limited to Table 3: Data for Co/Pt layers before and after annealing -XRD peaks visible are given by CoPt 3 (1 1 1) △, CoPt 3 (2 0 0), CoPt 3 (2 2 0), Pt(1 1 1) ▽. Filled shapes indicate a strong peak, underlined shapes indicate a weak peak. Average interfacial roughness of Co and Pt layers with the superlattice are given based on fitting of XRR data. A indicates that PMA was still present after annealing Mn, as the Mo does not absorb much Ga at 350°C. The increase in S for the 1.4 nm Mo heterostructure, indicates reordering of the Ru within MRG which should result in a decrease in magnetic properties. However, the squareness is still within acceptable limits and the coercivity increases, indicating that T comp has increased despite a lower c parameter. This is corroborated by the change in sign of the MRG switching direction in EHE, showing that T comp is now above RT. This effect is less prominent with the 2 nm Mo heterostructure, but still indicates an increase in T comp. In this case L c and have both increased without any change in S. With more material to diffuse, the additional Mo inclusions maintain chemical ordering of the Ru 4d site. With the thin 1.4 nm spacer, a weak CoPt 3 (2 0 0) peak is present, which becomes stronger after annealing. By contrast, there is a clear CoPt 3 (2 2 0) peak present when using a 2 nm spacer layer, which remains after annealing. This is the only case we witnessed where magnetic anisotropy of the Co/Pt was still perpendicular to the film surface after annealing. There is no clear Mo texture visible in XRD. Co and Pt layers both have moderate increases of roughness, however the heterostructure with a 2 nm spacer layer has higher initial and final roughness. Discussion Strain plays a significant role in the properties of MRG thin films, and crystalline point defects have previously been discussed as a source of electronic doping that maintains strain within the lattice. As demonstrated by use of a TiN spacer, annealing of MRG removes line and planar-type crystalline defects, which relaxes the lattice. These types of defects have previously been identified in MRG from HRTEM. This results in a 60 % to 70 % loss of tetragonal distortion of the unit cell (where a 100 % reduction would indicate a fully cubic cell). It is clear here that this is responsible for the reduction of coercivity and squareness in magnetic hysteresis due to the reorientation of the magneto-crystalline anisotropy into the plane. This effect is much stronger than could be attributable to Rubased anti-sites, so it is not possible here to determine their contribution. Where diffusion is discounted, there is a correlation between strain and chemical ordering within MRG, consistent with. The diffusion of different materials has varying effect on MRG, for example with V causing significant disorder of the crystal structure, ultimately resulting in the formation of additional intermetallic phases. The choice of a suitable spacer material is based on a requirement to maintain magnetic properties of MRG after processing. Hf and Mo are strong candidates for future applications, as in both cases, the magnetic hysteresis is reliable with a change in squareness <10 % from the as-deposited state. This is especially important in magnetoresistive devices which rely upon the relative orientation of magnetic moments between the free and reference layers. T comp is sensitive to the number of valence electrons within MRG, and increases linearly with n v. Both Hf and Mo appear to donate valence electrons to the film, as indicated by the increase in T comp. Based on Slater-Pauling rules, both Hf and Mo would donate ∼ 0.2 electrons per unit cell of MRG for the considered solubility. This contextualises the same effect seen in our previous work using thin interlayers. The results for these materials indicate a complex interplay between strain and film defects when we consider incorporation of additional valence electrons into the unit cell, that results in retention of perpendicular anisotropy. The strongly bonded compounds TiN and HfO x do not diffuse. However, the heterostructure using the thicker, partially oxidised HfO x spacer layer more resembles the structures using a Hf spacer layer in behaviour due to diffusion of metallic species closer to the MRG interface where the layer is not fully oxidised. Typically we see either CoPt 3 (2 0 0) or CoPt 3 (1 1 1) texture in the free layer, however in the case of the 2 nm Mo heterostructure there appears a CoPt 3 (2 2 0) peak. It is of interest that of all the structures, this is the only one that maintained perpendicular anisotropy in the Co/Pt after annealing. We can surmise that a mixture of weak (1 1 1) and (2 0 0) indicates an amorphous interface between spacer and the first Co layer, which is then crystallised and induces a preferential texture on the superlattice during annealing. Annealing results in an increase in interfacial roughness within the superlattice. PMA after annealing is independent on the degree of roughness measured, and is instead correlated with the appearance of CoPt 3 phases which are the result of intermixing. The superlattice which forms a CoPt 3 (2 2 0) phase does not loose perpendicular anisotropy, which we attribute here to the additional strain on the remaining Co/Pt interfaces induced by the crystal texture. As Mo is an element of comparable atomic weight to Pt, the additional orbital contribution at the interface between spacer and superlattice likely contributes to the anisotropy rather than any strain induced by epitaxial growth, considering that the Mo has no visible texture itself. PMA after annealing when using a 2 nm Mo spacer, when there is none present using a 1.4 nm Mo spacer, indicates that counter diffusion of MRG has an effect on the interfacial relationship between the spacer and the initial Co layer of the superlattice. Conclusions This study has enabled us to characterise the effects of various spacer layers on the structural and magnetic properties of both the MRG and the Co/Pt superlattice, which will be useful for developing perpendicular GMR and TMR structures that can withstand annealing at 350°C. The PMA of MRG is more robust, since it depends on strain imposed by the MgO substrate. That of the Co/Pt multilayer is only maintained when a CoPt 3 (2 2 0) phase is developed by intermixing, with the help of Mo. Based on the effect of annealing MRG films capped with a TiN spacer, line and planar defects help to maintain the substrate-induced strain and the tetragonal distortion of the MRG crystal structure, which the perpendicular magnetic anisotropy is dependent on. Annealing causes these defects to be removed, which results in the partial collapse of tetragonal distortion and therefore magnetic properties dependent on the perpendicular anisotropy. There was no identifiable link between these properties and the presence of Ru-based anti-site disorder. The effect of strain on anisotropy is counteracted by the addition of valence electrons in the MRG unit cell In Co/Pt multilayers, interface roughness is the main antagonist of PMA due to the reduction of interfacial anisotropy. Intermixing results in the formation of a CoPt 3 phase, even before annealing. However, the development of CoPt 3 with (2 2 0) texture retains perpendicular anisotropy after a 350°C anneal. A Mo underlayer is proposed here as a viable solution. Hf and Mo will be useful as thin protective layers in future active devices based on MRG, as they are able to offset changes in strain and defect density to maintain the PMA of the MRG layer. The solubility of both materials within MRG provides additional valence electrons, modifying the Fermi level position, and therefore T comp as well as the overall magnetic properties. This is in contrast to V, which prefers to form intermetallic phases instead. Considering the enhanced high-temperature stability of the crystal, doping of MRG with these or similar materials, such as Zr, should be investigated. By tuning the Ru/dopant composition, desired magnetic properties should be easily achievable. |
TricyclohexylphosphateA Unique Member in the Neutral Organophosphate Family Abstract Tricyclohexylphosphate (TcyHP) was synthesised and characterized. The extraction of U(VI) and Th(IV) by TcyHP in ndodecane was studied and compared with tributylphosphate (TBP). The feasibility of the separation of Th and U with TcyHP has been explored and reported. The solubility of TcyHP in water at room temperature has been measured. The stoichiometry of the TcyHP solvates with Th(NO3)4 and UO2(NO3)2 was evaluated. The enthalpy of extraction of U(VI) by TcyHP was measured. The results of column runs with TcyHP impregnated Amberlite XAD7 resin for studying the loading and elution behavior of uranium from nitric acid medium are also reported in this paper. Hexavalent actinides form third phase with neutral organophosphate extractants only at very high nitric acid concentrations and high metal loading. However the presence of the three closed ring alkyl moieties in TcyHP is seen to lead to certain unique features with regard to the third phase formation behavior. It has been observed, for instance, that U(VI) forms third phase with this extractant even with highly polar diluents like 1chlorooctane. Further, the tendency for third phase formation with U(VI) is even higher than in the case of Th(IV), in contrast to the trend observed so far with other extractants. |
Functional alterations of type I insulin-like growth factor receptor in placenta of diabetic rats. The presence of type I insulin-like growth factor (IGF-I) receptors on placental membranes led to the hypothesis that these receptors might play a critical role in the rapid growth of this organ. Diabetes induces feto-placental overgrowth, but it is not known whether it modifies IGF-I receptor activity in fetal and/or placental tissues. To answer this question, we have partially purified and characterized placental receptors from normal and streptozotocin-induced diabetic rats. In normal rats, binding of 125I-IGF-I to a 140 kDa protein corresponding to the alpha subunit of the receptor was observed in cross-linking experiments performed under reducing conditions. Stimulation by IGF-I induces the autophosphorylation of a 105 kDa phosphoprotein representing the beta subunit of the receptor. In rats made hyperglycaemic and insulinopenic by streptozotocin injection on day 1 of pregnancy, placental IGF-I receptor-binding parameters were not different from controls on day 20 of pregnancy. In contrast, the autophosphorylation and kinase activity of IGF-I receptors of diabetic rats were increased 2-3-fold in the basal state and after IGF-I stimulation. The present study indicates that the rat placental IGF-I receptor possesses structural characteristics similar to that reported for fetal-rat muscle, and suggests that the high-molecular-mass beta subunit could represent a type of receptor specifically expressed during prenatal development. In addition, it clearly demonstrates that diabetes induces functional alterations in IGF-I receptor kinase activity that may play a major role in the placental overgrowth in diabetic pregnancy. |
Identification of a Prognostic Signature Associated With the Homeobox Gene Family for Bladder Cancer Background: Bladder cancer (BLCA) is a common malignant tumor of the genitourinary system, and there is a lack of specific, reliable, and non-invasive tumor biomarker tests for diagnosis and prognosis evaluation. Homeobox genes play a vital role in BLCA tumorigenesis and development, but few studies have focused on the prognostic value of homeobox genes in BLCA. In this study, we aim to develop a prognostic signature associated with the homeobox gene family for BLCA. Methods: The RNA sequencing data, clinical data, and probe annotation files of BLCA patients were downloaded from the Gene Expression Omnibus database and the University of California, Santa Cruz (UCSC), Xena Browser. First, differentially expressed homeobox gene screening between tumor and normal samples was performed using the limma and robust rank aggregation (RRA) methods. The mutation data were obtained with the TCGAmutation package and visualized with the maftools package. KaplanMeier curves were plotted with the survminer package. Then, a signature was constructed by logistic regression analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using clusterProfiler. Furthermore, the infiltration level of each immune cell type was estimated using the single-sample gene set enrichment analysis (ssGSEA) algorithm. Finally, the performance of the signature was evaluated by receiver-operating characteristic (ROC) curve and calibration curve analyses. Results: Six genes were selected to construct this prognostic model: TSHZ3, ZFHX4, ZEB2, MEIS1, ISL1, and HOXC4. We divided the BLCA cohort into high- and low-risk groups based on the median risk score calculated with the novel signature. The overall survival (OS) rate of the high-risk group was significantly lower than that of the low-risk group. The infiltration levels of almost all immune cells were significantly higher in the high-risk group than in the low-risk group. The average risk score for the group that responded to immunotherapy was significantly lower than that of the group that did not. Conclusion: We constructed a risk prediction signature with six homeobox genes, which showed good accuracy and consistency in predicting the patients prognosis and response to immunotherapy. Therefore, this signature can be a potential biomarker and treatment target for BLCA patients. INTRODUCTION Bladder cancer (BLCA) is a common urological tumor, and its morbidity and mortality rates are increasing year by year (). High recurrence and early metastasis lead to the poor prognosis of BLCA. The detection of exfoliated tumor cells in urine or bladder lavage samples has a high sensitivity (84%) for the diagnosis of high-grade BLCA but is less sensitive for lowgrade BLCA (). Cystoscopy, the main method for the diagnosis of BLCA, is invasive, time-consuming, and tedious. Currently, specific, reliable, and non-invasive tumor biomarker tests for the diagnosis and prognosis evaluation of BLCA are desperately needed. The homeobox gene family is a group with a homologous segment of approximately 180 bp in length that encodes a homologous domain of 60 amino acids and is an important transcriptional regulator that plays a vital role in tumor formation and development, regulating cell proliferation, migration, and apoptosis (Laughon and Scott, 1984;;). Current studies have shown that the homeobox gene family is aberrantly expressed in different tumors, such as bladder, bile duct, endometrial, and breast cancers (). In BLCA, ISL1 and LHX5 play important roles in multiple stages of bladder tumorigenesis (); ZHX3 promotes migration and invasion in vitro and in vivo (). Therefore, the homeobox gene family plays an important role in the development and progression of BLCA. Although progress has been made in the study of individual family members, the role and prognostic value of the homeobox gene family in BLCA remain unclear. In this study, we analyzed the mRNA expression of a large number of BLCA samples in public databases . We constructed a prognostic signature for BLCA based on six homeobox genes with significant differential expression between BLCA tissues and normal tissues. This signature can predict a patient's prognosis and response to immunotherapy and thus has good clinical application value. The design flow chart for the entire analysis process of this study is shown in Figure 1. Data Collection The RNA sequencing (RNA-Seq) data, clinical data, and probe annotation files of BLCA patients (providing 18 normal tissues and 406 tumor tissues) in TCGA were downloaded from the University of California, Santa Cruz (UCSC), Xena Browser (https://xenabrowser.net/). BLCA datasets GSE7476 (3 normal tissues and 9 tumor tissues), GSE13507 (69 normal tissues and 188 tumor tissues), GSE37815 (6 normal tissues and 18 tumor tissues), GSE65635 (4 normal tissues and 8 normal tissues), and GSE19423 (48 tumor tissues) were downloaded from the Gene Expression Omnibus (GEO) database (https://www.ncbi.nlm.nih. gov/geo/) using the R package "GEOquery" (Davis and Meltzer, 2007). All 344 homeobox gene family members were extracted from the Hugo Gene Nomenclature Committee (HGNC). The probe IDs in each BLCA dataset were transformed into gene symbols according to the annotation files. Identification and Integration of Differentially Expressed Genes The R package "limma" was used to identify DEGs between normal and tumor tissues in each BLCA cohort with cutoff criteria of adjusted p value <0.05 and |log fold change (FC)| > 0.5 (). DEGs acquired from the five BLCA cohorts were sorted by the log fold change (logFC) value, and then the five gene lists were integrated using the RobustRankAggreg (RRA) R package (). The RRA method is based on the assumption that if the gene rank is high in all datasets, the probability that the gene is differentially expressed is higher and the related p value is lower. Mutation Landscape Analysis TCGA BLCA mutation data containing 411 tumor samples were acquired from the R package "TCGAmutations." The mutation landscape for the six signature genes in BLCA was visualized using the R package "Maftools" (). Construction and Evaluation of the Prognosis Model We randomly divided the TCGA BLCA cohort (n 406) in a 7:3 ratio into a training dataset (n 285) and a testing dataset (n 121). Logistic regression analysis was used to integrate the prognostic value of the six homeobox family genes into a sixgene signature model for BLCA. The formula for calculating the risk score for each sample is as follows: We calculated the risk score using the expression profiles of each sample based on the formula of the signature model. Then, we divided the BLCA cohort into high-and low-risk groups based on the median risk score. The R package "survival ROC" was used to establish the receiveroperating characteristic (ROC) curves for predicting one-, three-, and five-year overall survival (OS) for the two risk groups. Furthermore, we used the R package "rms" to construct calibration curves and evaluate the precision of the one-, three-, and five-year OS predictions for the BLCA cohort. Estimation of Immune Cell Infiltration We identified a group of 782 genes that represent 28 immune cell types involved in innate and adaptive immunity to estimate the infiltration level of different immune cell types in the tumor microenvironment (). Subsequently, the single-sample gene set enrichment analysis (ssGSEA) algorithm with the R package "GSVA" was used to evaluate the infiltration level of each immune cell type based on the expression profiles of each sample in BLCA and the immune cell gene marker (). Functional Enrichment Analysis The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases include collections of gene sets associated with the function of cells and organisms. Functional enrichment analysis of a set of genes that are dysregulated under certain conditions revealed which GO terms or KEGG pathways are overrepresented for that gene set. The TCGA BLCA cohort was divided into high-risk and low-risk groups according to the median risk score. Then, the R package "limma" was used to identify DEGs between the two risk groups. GO and KEGG analyses of the DEGs between the two risk groups were performed using the R package "clusterProfiler" (). A cutoff value of adjusted p value < 0.05 was used to determine the significant pathways. Prediction of the Immunotherapy Response The response of each sample to PD-1/PD-L1 and CTLA4 inhibitors was evaluated according to the gene expression profiles of the BLCA cohort with the Tumor Immune Dysfunction and Exclusion (TIDE) algorithm (http://tide.dfci. harvard.edu) (). Survival Analysis The samples were divided into high-and low-risk groups based on the median risk score, and the differences in OS and progression-free survival between the high-risk and low-risk groups were estimated using the Kaplan-Meier method. Survival curves were compared using the log-rank test. The significance threshold was defined as p < 0.05. Statistical Analysis Statistical analyses were performed using the log-rank test for univariate analysis. Pearson's correlation test was used to assess the relationship between the risk score and immune markers, characteristic gene expression, and the immune cell infiltration score. The relationship between the characteristic gene expression and the immune cell infiltration score was also evaluated. Student's t-tests were used to determine statistical significance of differences between variables. Statistical significance was defined as p < 0.05. All statistical analyses were performed in R version 4.0.2. Identification of the Differentially Expressed Homeobox Gene Family Members in Bladder Cancer To screen differentially expressed homeobox genes (DEHGs) in BLCA, four GEO datasets, GSE7476, GSE13507, GSE37815, and GSE65635, as well as TCGA gene expression dataset containing 406 BLCA samples and 18 normal samples from the UCSC Xena Browser were obtained. The R package "limma" was used to Frontiers in Molecular Biosciences | www.frontiersin.org July 2021 | Volume 8 | Article 688298 determine the DEHGs of each dataset using |logFC| > 0.5 and adjusted p < 0.05 criteria, and the volcanoes were plotted ( Figures 2A-E). Furthermore, the RRA method based on the expression of each gene in all datasets was used to screen out the candidate genes (score < 0.05) (Supplementary Table 1). As a result, six homeobox genes, TSHZ3, ZFHX4, ZEB2, MEIS1, ISL1, and HOXC4, were screened out, and then the logFC values of each gene in different datasets were calculated and are shown in Figure 2F. Moreover, correlation analysis of the six homeobox genes was performed, and the results showed that there were significant positive correlations between most genes ( Figure 2G). Correlation of the Six Homeobox Genes With Clinical Status and Mutation Landscape To explore the clinical significance of these six genes, pancancer analysis in BLCA ( Figure 3A) and 23 other tumors Figure 1) was performed, and the results revealed that the expression of TSHZ3, ZFHX4, ZEB2, MEIS1, and ISL1 was significantly lower than that in normal tissues, while the expression of HOXC4 was higher than that in normal tissues, especially in BLCA, breast invasive carcinoma (BRCA), prostate adenocarcinoma (PRAD), and head and neck squamous cell carcinoma (HNSC). Furthermore, we analyzed the correlation between these six homeobox genes and tumor size, regional lymph node involvement, and distant metastases (TNM) as well as the BLCA stage and found that TSHZ3, ZFHX4, and ZEB2 were positively correlated with T stage, N stage, and BLCA stage, but there was no significant correlation with metastasis ( Figures 3B-E). In addition, we analyzed the mutation landscape of these six DEHGs in BLCA. Among the 411 samples, 19.46% had at least one gene mutation; ZFHX4 mutation was the most common change, accounting for 12% of mutations; ZEB2, TSHZ3, MEIS1, and ISL1 mutations accounted for 5, 3, 1, and 1% of all mutations, respectively. The waterfall diagram formed according to the mutation landscape of these six DEHGs showed that most mutations were missense mutations ( Figure 2H). The driver genes ERBB2, HDAC1, PARP1, ERBB3, FGFR3, mTOR, AXL, EZH2, FGFR1, FGFR2, CSF1R, KIT, FGFR4, RET, and ERBB4 are key targets in the treatment of BLCA. Furthermore, we assessed the correlations between these six genes and BLCA driver genes in the BLCA dataset, and it was found that these six genes have a strong correlation with these driver genes (Supplementary Figure 2). A High Risk Score Was Associated With a Poor Clinical Outcome The prognostic value of the six-homeobox-gene signature was evaluated in the training dataset and testing dataset. We calculated the risk score for each BLCA sample in the training set, ranked them according to this score, and divided them into high-risk and low-risk groups based on the median risk score. We used scatter plots to show the survival status of BLCA patients based on risk scores, and we then performed a chi-square test on the data ( Figures 4A,C). The results demonstrated that patients in the high-risk group had a higher mortality rate than those in the low-risk group (p 0.033). The heat map with the gene expression profile of these six homeobox genes showed that ISL1, ZFHX4, TSHZ3, and ZEB2 were more highly expressed in high-risk BLCA samples, while HOXC4 and MEIS1 were highly expressed in the low-risk group ( Figure 4E). The results for the testing dataset were consistent with those for the training dataset ( Figures 4B,D,F). Kaplan-Meier analysis was performed on the training dataset, the testing dataset, and all datasets ( Figures 4G-I), and the results revealed that the survival time of the low-risk group was significantly longer than that of the high-risk group. GO Function Annotation and KEGG Pathway Analysis Between the High-Risk and Low-Risk Groups The DEHGs between the two risk groups were analyzed using GO functional annotation and KEGG pathway analysis with the R software package "clusterProfiler." The GO analysis of biological process (BP), molecular function (MF), and cell component (CC) terms showed that most of the enriched terms were related to immunity, including B cell-mediated immunity, immunoglobulin-mediated immune response, immunoglobulin complex, and antigen binding ( Figure 5A). The KEGG pathway analysis showed that the DEHGs were mainly enriched in cytokine-cytokine receptor interactions, Staphylococcus aureus infection, cell adhesion molecules, etc., most of which are related to immunity ( Figure 5B). The Signature Composed of Six Homeobox Genes Was Closely Related to Immunity Since the results of the GO functional annotation and KEGG pathway analysis showed that the signature was related to immunity, analysis of the risk score and immune cell infiltration was then performed to further confirm the conclusion. The results showed that there were differences in the infiltration of most immune cells, except for CD56dim natural killer cells, eosinophils, and monocytes, between the high-and low-risk groups, which demonstrated that the signature was significantly correlated with immune infiltration ( Figure 6A). In addition, we analyzed the correlation of each gene with the infiltration of immune cells, and the results indicated that TSHZ3, ZFHX4, and ZEB2 were related to almost all immune cell types and that MEIS1, ISL1, and HOXC4 were related to some immune cell types ( Figure 6B). Furthermore, we also analyzed the correlation analysis between these six genes and cytokines related to T cell function. The results showed that five out of the six genes, TSHZ3, ZFHX4, ZEB2, MEIS1, and ISL1, had a strong correlation with most cytokines, while HOXC4 had a strong correlation with IL-17A (Supplementary Figure 3). Similarly, the analysis of the correlations between the expression of these six homeobox genes and immune checkpoints showed that TSHZ3, ZFHX4, and ZEB2 were significantly correlated with the expression of CTLA-4, PD-L1, PD-L2, and PD-1. MEIS1 was strongly correlated with the expression of PD-1. In addition, ISL1 was significantly correlated with CTLA-4, PD-L2, and PD-1 expressions ( Figure 6C). Then, we analyzed the relationship between the risk score and the response to immunotherapy. The samples were divided into response and no-response groups, and the difference in risk scores between the two groups was assessed. The results showed that the risk scores were higher in the no-response group than in the response group ( Figure 6D). Evaluation and External Validation of the Signature Model Performance The ROC curves of the training set, testing set, and entire dataset (combination of training and testing sets) were plotted, and the area under the ROC curve (AUC) was calculated to verify the accuracy of this signature. The AUCs for one-, three-, and fiveyear OS were 0.631, 0.606, and 0.609 in the training set; 0.679, 0.652, and 0.671 in the testing set; and 0.647, 0.629, and 0.633, respectively, in the entire dataset ( Figures 7A-C). To compare the consistency of the model predictions with actual clinical outcomes, calibration curves for one-, three-, and five-year OS were constructed for the training set (Supplementary Figures 4A-C), testing set (Supplementary Figures 4D-F), and entire dataset ( Supplementary Figures 4G-I). The calibration curves showed satisfactory agreement between the predicted and observed values for one-, three-, and five-year OS. We further validated the prediction ability of this prognostic signature using the GEO datasets GSE13507, GSE19423, and GSE37815 for external validation. The risk score of each sample was calculated, and the samples were divided into high-risk and low-risk groups based on the optimal splitting point. Kaplan-Meier analysis of GSE13507 (p 0.17), GSE19423 (p 0.027), and GSE37815 (p 0.012) showed that the highrisk group tended to have a shorter survival time than the low-risk group (Figures 7D-F). DISCUSSION There are many studies on biomarkers of BLCA, such as urine cytology and urine biomarkers; the detection of exfoliated tumor cells in urine or bladder lavage has a high sensitivity for the diagnosis of high-grade BLCA but is less sensitive for low-grade BLCA. There are many biomarkers with unique functions, such as radiotherapy markers, chemotherapy markers, and immunotherapy markers, but these markers have a single function (Giordano and Soria, 2020), and most of them involved single targets, which easily cause false-positive or false-negative results. The application of RNA-Seq and bioinformatic analysis of databases has provided a theoretical basis for mechanistic studies of tumorigenesis and development. Zhu et al. identified some immune-related genes as prognostic factors in BLCA (). Lian et al. established a signature including eight long non-coding RNAs as a candidate prognostic biomarker for BLCA (). At present, there are few biomarkers that can predict both clinical outcomes and immunotherapy response. In this study, a clinical prediction model containing six homeobox genes was constructed through next-generation sequencing (NGS), which can not only predict the prognosis of patients but also predict the patient's immune response. With the popularity of sequencing technology, its price and convenience continue to improve, and this study has good clinical applicability. Although the homeobox gene family is closely related to BLCA (), few studies have focused on its prognostic value in BLCA. Therefore, we analyzed the RNA-Seq data of a large number of samples from TCGA and GEO public databases and screened out six significant DEHGs, namely, TSHZ3, ZFHX4, ZEB2, MEIS1, ISL1, and HOXC4, by the RRA method. Some of these six homeobox genes have been reported to regulate tumor progression and were identified as potential prognostic markers in previous studies. For example, aberrant HOXC4 expression is prevalent and plays an important role in the development of prostate cancer (Luo and Farnham, 2020). Moreover, HOXC4 can promote hepatocellular carcinoma progression by transactivating Snail (). The expression of TSHZ3 is significantly downregulated in human glioma tissues and cell lines, and overexpression of TSHZ3 decreases the invasiveness of U87 and U251 glioblastoma cells (). In addition, the downregulation or deletion of TSHZ3 function is involved in the pathogenesis of ovarian cancer (), which suggests that TSHZ3 plays an oncogenic role. ZFHX4 is required for the regulation of glioblastoma tumor-initiating cells, and its inhibition leads to reduced tumorigenesis and increased glioma-free survival time. Mutations in ZFHX4 are strongly associated with a poor prognosis, and downregulation of ZFHX4 inhibits the progression of esophageal squamous carcinoma (). ZEB2 can promote the migration and invasion of gastric cancer cells by regulating epithelial-mesenchymal transition (EMT) and is a potential target for gene therapy of invasive gastric cancer (). Deregulation of negative feedback between GATA3 and ZEB2 can promote breast cancer metastasis (). The expression level of MEIS1 in acute myeloid leukemia (AML) is negatively correlated with prognosis (). ISL1 plays an important role in a variety of cellular processes, including cytoskeleton genesis, organogenesis, and tumorigenesis (Zheng and Zhao, 2007), and has been found to be a highly specific marker for pancreatic endocrine tumors and metastases (). In addition, it was also significantly associated with aggressive tumor characteristics, tumor recurrence, tumor progression, and disease-specific mortality (DSM) in BLCA and plays an important role in multiple stages of bladder tumorigenesis (). We constructed a predictive signature based on these six prognostic homeobox genes. The expression profiles of the signature genes showed that tumors with higher risk scores tended to exhibit elevated ISL1, ZFHX4, TSHZ3, and ZEB2 levels, while those with lower risk scores tended to exhibit elevated HOXC4 and MEIS1 levels. Patients with high risk scores according to the signature had a poor prognosis. Then, we performed survival analysis on the training dataset, the testing dataset, and all datasets. The results showed that the high-risk group had a shorter survival time than the low-risk group. Finally, we validated the performance of the signature using GEO datasets. Overall, the signature can predict the prognosis of patients accurately and has good prognostic value. Errors in the process of DNA replication are random and universal and subject to correction and repair by the DNA Frontiers in Molecular Biosciences | www.frontiersin.org July 2021 | Volume 8 | Article 688298 mismatch repair system. Once the dynamic balance between the two is disrupted, it will easily lead to the occurrence of gene mutations, which will affect the expression of the corresponding genes and facilitate tumorigenesis and development (). We analyzed the mutation landscape of these six genes in BLCA. Among the 411 samples, 19.46% had at least one gene mutation. Driver genes are important genes associated with tumor development and play a driving role in the process of cancer development and progression (). Currently, the driver genes of BLCA include ERBB2, HDAC1, PARP1, and mTOR. These genes are important targets in BLCA treatment (). We performed correlation analysis between these six genes and BLCA driver genes in the BLCA dataset and found that these six genes have a strong correlation with the driver genes. The results indicated that the six homeobox genes play an important role in the development of BLCA and that the signature could be used in the prediction of BLCA prognosis. As a major component of the tumor microenvironment (TME), immune infiltration has been shown to contribute to tumor progression and the immunotherapeutic response (), and tumor-infiltrating immune cells, particularly T cells, are the cellular basis of immunotherapy. A better understanding of immune cells in the TME is critical to deciphering the mechanisms of immunotherapy, defining predictive biomarkers, and identifying new therapeutic targets (Zhang and Zhang, 2020;). In our GO analysis, most of the enriched functional terms were immune-related, and the same results were obtained by KEGG analysis. Then, the analysis of the risk score and immune cell infiltration showed that there were differences in the infiltration of most immune cells between the high-and low-risk groups, which demonstrated that this signature was significantly correlated with immune infiltration. Immune cells in tumors work together to control tumor growth, and the effectiveness of immunotherapy depends on the synergistic response of innate and adaptive immune cells, particularly T cells (). The function of T cells is usually classified based on whether they secrete specific effector molecules or cytokines, and effector CD4 + T cells include different functional subtypes (Th1 cells secrete IL-2 and IFN-; Th2 secretes IL-4, -13; Th17 secretes IL-17A, etc.), while effector CD8 + T cells secrete cytotoxic mediators (perforin and granzymes) or proinflammatory cytokines (TNF-, IFN-) (). Therefore, in order to analyze the correlation between these six genes and T cell function, we further analyzed the correlation of these six genes with those cytokines, and the results showed that five out of the six genes, TSHZ3, ZFHX4, ZEB2, MEIS1, and ISL1, had a strong correlation with most cytokines, while HOXC4 had a strong correlation with IL-17A. The expression of the six homeobox genes in the signature was correlated with most immune checkpoints (CTLA-4, PD-L1, PD-L2, and PD-1). At present, the most commonly used immunotherapy drugs in clinical practice are immune checkpoint inhibitors. Therefore, we analyzed the relationship between the risk score and the response to immunotherapy. The results showed that the risk scores were higher in the no-response group than in the response group. Above all, this signature was highly correlated with immunity and will be a good predictor of the patient's response to immunotherapy. However, this study has some limitations. This study is based on TCGA and GEO databases, the reliability of its data is unknown, and this study lacks experimental evidence and is mostly based on bioinformatics prediction, which limits its immediate applicability in clinical practice. In addition, the number of non-tumor tissues assessed in this study is rather small (n 18), which constitutes a potentially important bias influencing the results. The GEO datasets used for validation were relatively small. Further validation of model prediction accuracy with clinical data is needed. CONCLUSION We constructed a risk prediction signature with six homeobox genes, which showed good accuracy and consistency in predicting the patient's prognosis and the response to immunotherapy. Therefore, this signature could be a potential biomarker and treatment target for BLCA patients. DATA AVAILABILITY STATEMENT The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found in the article/ Supplementary Material. ETHICS STATEMENT Written informed consent was obtained from the individual(s) for the publication of any potentially identifiable images or data included in this article. AUTHOR CONTRIBUTIONS TY made substantial contributions to the conception, design, interpretation, and preparation of the final manuscript. BD, JL, WS, JS, MZ, SZ, and YM participated in the coordination of data acquisition and data analysis and reviewed the manuscript. DL reviewed and revised the manuscript. Supplementary |
Ram is working on two high performance pickups, including the most powerful one ever made.
Sources tell 5thGenRams.com that the automaker will soon be launching a Ram 1500 inspired by the Rebel TRX concept truck that was shown two years ago.
The report says that it will be offered with both a new 520 hp 7.0-liter V8, called the Banshee, and the 707 hp supercharged V8, currently available in the Dodge Charger and Challenger Hellcats and Jeep Grand Cherokee Trackhawk.
Unlike those street machines, the TRX Concept was conceived to take on the Ford F-150 Raptor as a high speed, off-road truck designed for flying across the desert at triple-digit speeds, with a wide stance and long-travel suspension.
Prototypes of the production version based on the recently introduced 2019 Ram 1500 have been already been spotted being tested, and the trucks are expected to arrive for the 2021 model year. |
Giuseppe Biava
AlbinoLeffe
A centre back, Biava started his career with the Leffe youth team, before moving to newly promoted Serie D team Albinese in 1995. During his time with Albinese before the 1998 merger with the Leffe to found AlbinoLeffe, Biava achieved a promotion to Serie C2 in 1997. In 1998–99, Biava helped AlbinoLeffe to ensure promotion to Serie C1. After a one-year loan at Serie C2 side Biellese, Biava returned to AlbinoLeffe in 2001, and was part of the team that won the promotion playoffs in 2003, thus ensuring them a Serie B place.
In 2003–04, Biava marked his Serie B debut, and scored the goal which ensured the first AlbinoLeffe victory in the league, a 1–0 win against Fiorentina.
Palermo
His performances in the league provoked interest from Serie B club Palermo, which signed him during the January 2004 transfer window. Biava immediately gained a place in the regular lineup, forming a defensive line together with Pietro Accardi and leading the rosanero back to Serie A after over 30 years.
Biava was confirmed by head coach Francesco Guidolin as a key player during the 2004–05 season, coincidentally his first season in the top flight, which ended with a historical first qualification for Palermo in the UEFA Cup. However, he did not confirm his performances in the following season, where he was mostly featured as backup player. With Guidolin back at the helm of Palermo in 2006–07, Biava regained a more important role in the Palermo squad, returning to play at his usual levels.
During the summer 2007, Biava refused an offer from his childhood team Atalanta, preferring instead to stay at Palermo even though the club management could not ensure him a place as a regular. He successively agreed a contract extension with the rosanero until June 2009.
Genoa
In June 2008 Biava was sold to Genoa for €500,000, with Cesare Bovo moving the opposite way. At Genoa, he quickly established himself as a regular for the rossoblu. In their 2008–09 Serie A campaign ending in fifth place he partnered with Salvatore Bocchetti and/or Matteo Ferrari. In the first half of 2009–10 season he often partnered with Bocchetti but in January faced competition in new signing Dario Dainelli while the team's coach preferred a 3–5–2 formation with 3 central defenders and 2 wing-backs.
Lazio
On 1 February 2010, Biava joined Lazio for a transfer fee of €800,000 (including other costs Lazio paid a total of €1.04 million). Along with new signing André Dias, he became the backbone of the Lazio team starting in 11 matches in the second half of the 2009–10 season and helped the club survive the relegation battle.
In the 2010–11 season Biava made 36 appearances, guiding Lazio to a strong 5th-place finish.
In the 2011–12 season, Biava was limited to 31 appearances due to muscle issues.
He made a career high 43 appearances in all competitions in the 2012–13 season, leading Lazio to the quarter finals of 2012–13 UEFA Europa League where they were knocked out by Fenerbahçe, and helped Lazio defeat traditional rivals A.S. Roma to win the 2012–13 Coppa Italia.
Biava missed large portions of the first half of the 2013–14 season, but finished the season strongly, making 24 appearances in all competitions.
Atalanta
On 17 July 2014, Biava signed for home province club Atalanta B.C. as a free agent. |
LAS CRUCES - Alex Moon has a new idea, and the biology doctorate student at New Mexico State University is trying to patent it. Through the process, the Patent and Trademark Resource Center at NMSU’s Zuhl Library has been a valuable resource.
Established at NMSU in October 2016, the PTRC is the only office in New Mexico and the surrounding region and is officially affiliated with the United States Patent and Trademark Office in Alexandria, Virginia.
“This program is set up through the USPTO to help inventors who don’t have the support or money up front to get going on the patent process,” said David Irvin, NMSU business and government documents librarian and PTRC representative.
The PTRC can help individuals conduct prior-art searches for patents and trademarks so they can determine if a patent or trademark already exist before proceeding with the process. The PTRC is a free service and open to the public.
Moon, who is trying to patent his method for building 3D printed casts, filled LLC paperwork in January 2018 for his business and then visited the PTRC and talked with Irvin to research the viability of his idea.
The PTRC provides access to not only the research software and USPTO training materials but also referrals to the ProBoPat program, which connects individuals to pro bono intellectual property attorneys.
“It saves inventors money to be able to have access to an office like this,” Irvin said. “It also is part of the extension and outreach mission of the university ... to reach out and provide resources for inventors, innovators and entrepreneurs who are applying for patents or trademarks.
Moon encourages local inventors to visit the PTRC.
“Don’t be afraid to use it. It’s a very awesome resource that is there and not many people utilize, which is really sad,” he said.
Since the PTRC office opened, Irvin estimates 130 people have been helped. Starting this summer, the PTRC will be open all year, previously the office closed in the summer.
Additionally, Irvin mentioned the NMSU Library collects and binds plant patents from the USPTO. Since 1994, NMSU has received plant patent volumes that are housed in the Branson Library.
For more information visit http://nmsu.libguides.com/PTRC. |
An Application of Tabu Search Algorithms and Genetic Algorithms in Collaborative Logistics Optimization This paper discusses a new way to solve the Vehicles Routing Problem (VRP) of logistics with the use of Taboo Search Algorithms (TSA) and optimize the new way and the distribution center based on Genetic Algorithms (GA). This study focuses on the incorporating of sugar industry and Milled Rice Distribution Center Management in Thailand for the export channel. This provides a systematic and framework to solve the cost minimization problem of sugar transports and Milled Rice transports from the mills to a seaports. The results demonstrate, there is not a useful tool for minimizing the cost and new way, but the tool can manage distribution center, and seaport exporting. While the focus of the paper is on sugar supply chain and rice supply chain, much of the information is relevant to Distribution Center Management of other agricultural commodities as well. |
The Bulgarian cabinet approved on Wednesday the country's participation in negotiations for the purchase of new fighter jets.
This was announced by Defence Minister Nikolay Nenchev after the government granted him mandate to head negotiations with Belgium, the Netherlands and Greece.
It was still not clear whether the negotiations will concern the purchase of new jets or second-hand ones, daily Dnevnik reports.
Nenchev clarified that the above countries offered second-hand F-16s, but it was not excluded for negotiations to be led with producers on the purchase of new jets.
In order for ensuring the proper functioning of the Bulgarian air force, a squadron of least nine jets should be purchased.
The Defence Minister added that the Bulgarian state is not pushed by deadlines for the purchase of new fighter jets as the issue with the repair of the MiG-29s has been resolved.
An agreement on the repair of two or four of the engines is expected to be signed with Poland by the end of next month at the latest.
The second stage foresees for the repair of another 10-12 engines.
Nenchev pointed that Poland offered much more favourable terms and lower prices than Russia on the repair of the MiG-29s.
As regards the safeguard of the country's air space, which was regulated within the framework of NATO's Air Policing missions, only Poland has expressed interest. |
Challenging the validity of imposing contraindications to thrombolysis for acute ischemic stroke A colleague once challenged grand rounds attendants to identify any pharmacologic treatment for stroke, other than recombinant tissue plasminogen activator (rtPA), which, 15 years after Food and Drug Administration approval, still evoked a mental checklist of eligibility criteria, with numerous contraindications, yet the audience was mute. Are all IV thrombolysis exclusion criteria really necessary? The Simplified Management of Acute Stroke Using Revised Treatment (SMART) protocol considers all ischemic stroke patients for thrombolysis regardless of common rtPA exclusion criteria, contending that such criteria are consensus-based, not evidence-based; nearly 20% of all ischemic stroke patients received IV rtPA without an increase in adverse events.1 SMART proposed that exclusion criteria be critically reevaluated,1 with many investigators adopting an empirical approach to this challenge.2,3 Concerns over poorer post-thrombolysis outcomes in patients with a history of prior stroke and diabetes prompted trialists to exclude these patients for the European Cooperative Acute Stroke Study (ECASS)3.4 Prior stroke reduces the benefits from thrombolysis.5 Furthermore, there is a clear association of hyperglycemia with worse outcomes in ischemic stroke, through multiple possible mechanisms6: increased plasminogen activator inhibitor-1 activity, resistance to antithrombotic agents, and |
Last year, in the inaugural weeklong Fedstival, Government Executive and Nextgov convened leading federal officials and thinkers to share ideas about tackling government’s biggest challenges.
Now we’re deep into planning for Fedstival 2017, which will take place from Sept. 18-22 in Washington. The series of events culminates in Bold Friday, during which federal innovators from all corners of government tell about the important work they’re doing in a series of rapid-fire presentations.
At last year’s Bold Friday, experts from the National Defense University, the Office of Management and Budget, the U.S. Agency for International Development, the National Park Service and many other federal organizations shared stories of their cutting-edge work. This year, a new group of federal leaders, selected by a panel of Government Executive and Nextgov editors, will take the stage to tell their peers and colleagues how they’re making a difference in technology, management strategy and workforce development across government agencies.
If you or someone you know fits that bill, we want to hear about it. Nominations are now open for this year’s Bold Friday presentations. This is your chance to highlight the important work you’re doing, share your ideas with peers from other agencies and learn from their experiences.
Overall, this year’s Fedstival will take an in-depth look at the new administration’s efforts in management, workforce and IT innovation. We’ll convene a wide range of practitioners and observers for conversations, debates, workshops, live events, networking and much more. |
The Middle East The undeniable threat that Iran poses to the other countries of the Middle East has its roots in the fundamentalist Islamist ideology that the ruling clerics there espouse. The clerics aspire to evict the long-engrained military forces, aid, and other influences of the United States from the region and to thus become the dominant power. In pursuit of these ambitious goals, Iran has trained and sponsored various proxy forces and terrorists in other nearby countries and has sought to acquire nuclear weapons for the state. Ultimately, these efforts have served to undermine the prospects of building peace in the region. |
Ever since MacDiarmid, Hideki Shirakawa, and Heeger invented conducting polymers and made it possible to dope these polymers over the full range from insulator to metal, a new field of research bordering chemistry and condensed-matter physics emerged, which created a number of opportunities in the application in photoelectronic, electronic and electrochemistry. Conducting polymers have the advantages of stable physical and chemical properties and high conductivity. More significantly, conducting polymers provide an excellent interface between the electronic-transporting phase (electrode) and the ionic-transporting phase (electrolyte). In addition, the conductivity of conducting polymers is dependent on variables such as redox state and pH, which makes conducting polymers ideal for smart materials such as sensors.
In recent decades, conducting polymer hydrogels have received increasing attention for its promising applications in biosensors, chemical sensors, bioelectrodes, biobattery, microbial fuel cell, microbial electrolysis cell, medical electrodes, artificial muscle, artificial organ, drug release, and biofuel cells, etc. due to the following reasons:
1) Conducting polymer hydrogels have nanostructured framework and sufficiently large interfacial area, which enhanced the diffusion of ions and molecules, as well as the transport of electrons;
2) Conducting polymer hydrogels have a softer mechanical interface comparing to conventional metal electrodes;
3) Conducting polymer hydrogel have a biocompatible environment closely matching those of biological tissues.
To date, only a few limited methods were developed to synthesize conducting polymer hydrogels due to the difficulty in achieving the two prerequisite conditions for conducting polymers to form hydrogels: 1) hydrophilicity of polymer; 2) chemical or physical crosslinking between polymer chains. Synthesis of conducting polymer hydrogels has been carried out by following methods:
1) Synthesizing conducting polymer in the matrix of non-conducting polymer hydrogels (i.e. forming a composite material consisting of non-conductive hydrogel and conducting polymer);
2) Using multivalent metal ions such as Fe3+ or Mg2+ to crosslink water soluble conducting polymer such as poly(3,4-ethylenedioxythiophene) (PEDOT) by ions interacting with the negatively-charged electrolytic dopant;
3) Crosslinking polyaniline (PAni) by chemical reaction between epoxy group of the non-conducting crosslink agent and the amino group on PAni.
However, all of the above methods introduce impurities or nonfunctional materials, such as metal ions or nonfunctional polymers, thereby deteriorate the conductivity, electroactivity or biocompatibility of conducting polymers. In method 1), biocompatible composite material can be formulated using conducting polymer held in the matrix of hydrogels such as poly (vinyl alcohol), poly (ethylene glycol), and polyacrylamide chitosan, poly(2-hydroxyethyl methacrylate), poly (acrylic acid), poly (acrylamide), alginate hydrogel, etc. In this case, however, the non-functional polymer hydrogel impurity undoubtedly results in the lowering of conductivity and electroactivity of the material, which reduces the performance of electrodes and sensors. In method 2), crosslinked conducting polymer hydrogel is induced by ionic interaction of metal ions with negative polyelectrolyte dopant, which reduces the biocompatibility and enzyme activity of the hydrogels as high quantities of metal ions are required to form gels. In method 3), crosslinked PAni is made by the reaction between the epoxy crosslinking group and amino group on PAni main chain, which greatly reduces the conductivity of conducting polymers. In summary, the existing synthetic methods cannot meet the requirements of vast applications of conducting polymers, such as biomedical devices, biobattery, and microbial fuel cell. |
Men Versus Women. Although women represent a large segment of our cardiovascular patients, adequate, high-quality clinical trial data on women remains scarce and disproportionally lower than what is needed to guide practice decisions. A recent analysis from the Food and Drug Administration highlighted that there is significant underrepresentation of women in clinical trials involving coronary disease, acute coronary syndrome, and myocardial infarction.1 Because women present at older ages, often have different disease manifestations, and may differ in response to treatments, the Food and Drug Administration and others have provided formal guidance on the inclusion of women in clinical trials, but this issue remains far from resolved. Women with coronary disease and acute coronary syndrome present an additional challenge to researchers and clinicians. There are multiple examples in the literature suggesting that women may have differential responses to cardiovascular therapies, but this has often been later disproven on further study and improved patient risk stratification. For example, GP IIb/IIIa (glycoprotein IIb/IIIa) inhibitors were initially thought to increase the risk of bleeding for women presenting with nonST-segmentelevation myocardial infarction and were thus widely underused, despite evidence about the potential ischemic benefits. Much of this sex difference in bleeding may have been attributable to more frequent overdosing of GP IIb/IIIa inhibitors in women compared with men.2 Importantly, despite some early observations that women might benefit less than men treated with potent platelet inhibition, when analyses were done among troponin positive patients, GP IIb/IIIa inhibitors were found to be equally efficacious in men and women.3 This is an example of the importance of better defining the patient populationfor both men and womenthat is most likely to benefit from aggressive pharmacological interventions. The 2014 American College of Cardiology/American Heart Association nonST-elevation acute coronary syndromes guidelines explicitly recommend that women presenting with acute coronary syndrome should be treated with the same pharmacological interventions as men (Class I recommendation).4 In this issue of Circulation: Cardiovascular Interventions, Berry et al5 once again demonstrate the importance of establishing clear inclusion criteria (ie, which patients will benefit) when studying antithrombotic therapies for patients with coronary disease. Using data from the DAPT study (Dual Antiplatelet Therapy), the authors examined whether the risks/benefits of prolonged dual antiplatelet therapy differed by sex. The DAPT study assessed the effectiveness of dual antiplatelet therapy (clopidogrel or prasugrel in combination with aspirin) beyond 12 months after coronary stenting. Of 7175 enrolled women, 2925 (40.7%) met the inclusion criteria for randomization, which included good adherence to 12 months of DAPT Fatima Rodriguez, MD, MPH Robert A. Harrington, MD EDITORIAL |
Molecular Characterization of Cereal Yellow Dwarf Virus-RPV in Grasses in European Part of Turkey Abstract Yellow dwarf viruses (YDVs) are economically destructive viral diseases of cereal crops, which cause the reduction of yield and quality of grains. Cereal yellow dwarf virus-RPV (CYDV-RPV) is one of the most serious virus species of YDVs. These virus diseases cause epidemics in cereal fields in some periods of the year in Turkey depending on potential reservoir natural hosts that play a significant role in epidemiology. This study was conducted to investigate the presence and prevalence of CYDV-RPV in grasses and volunteer cereal host plants including 33 species from Poaceae, Asteraceae, Juncaceae, Geraniaceae, Cyperaceae, and Rubiaceae families in the Trakya region of Turkey. A total of 584 symptomatic grass and volunteer cereal leaf samples exhibiting yellowing, reddening, irregular necrotic patches and dwarfing symptoms were collected from Trakya and tested by ELISA and RT-PCR methods. The screening tests showed that 55 out of 584 grass samples were infected with CYDV-RPV in grasses from the Poaceae family, while none of the other families had no infection. The incidence of CYDV-RPV was detected at a rate of 9.42%. Transmission experiments using the aphid species Rhopalosiphum padi L. showed that CYDV-RPV was transmitted persistently from symptomatic intact grasses such as Avena sterilis, Lolium perenne and Phleum exratum to barley cv. Barbaros seedlings. PCR products of five Turkish RPV grass isolates were sequenced and compared with eleven known CYDV-RPV isolates in the GenBank EMBL databases. Compared nucleotide and amino acid sequences of CYDV-RPV isolates showed that the identities ranged from 40.38 − 95.86 % to 14.04 − 93.38%, respectively. In this study, 19 grass species from the Poaceae family and two volunteer cereal host plants were determined as natural reservoir hosts of CYDV-RPV in the cereal growing areas of Turkey. |
Comparison of 99mTc- and 18F-Ubiquicidin Autoradiography to AntiStaphylococcus aureus Immunofluorescence in Rat Muscle Abscesses 99mTc-ubiquicidin (UBI) 29-41 is under clinical evaluation for discrimination between bacterial infection and unspecific inflammation. We compared the distribution of 99mTc-UBI 29-41, the potential PET tracers 18F-UBI 29-41 and 18F-UBI 28-41, and 3H-deoxyglucose (DG) in rat muscle abscesses to that of antiStaphylococcus aureus immunofluorescent imaging. Methods: Calf abscesses were induced in 15 CDF-Fischer rats after inoculation of Staphylococcus aureus. One to 6 d later, either 18F-UBI 29-41 and 3H-DG (n = 5) or 18F-UBI 28-41 and 3H-DG (n = 6) or 99mTc-UBI 29-41 and 3H-DG (n = 4) were injected simultaneously. Dual-tracer autoradiography of the abscess area was compared with the distribution of bacteria and macrophages. Results: The UBI derivates exhibited increased uptake in the abscess area that partly matched 3H-DG uptake and macrophage infiltration but showed no congruity with areas that were highly positive for bacteria. Conclusion: A specific binding of UBI derivatives to Staphylococcus aureus in vivo could not be confirmed in this study. |
The roles of microRNAs in regulation of mammalian spermatogenesis Mammalian spermatogenesis contains three continuous and organized processes, by which spermatogonia undergo mitosis and differentiate to spermatocytes, follow on meiosis to form haploid spermatids and ultimately transform into spermatozoa. These processes require an accurately, spatially and temporally regulated gene expression patterns. The microRNAs are a novel class of post-transcriptional regulators. Cumulating evidences have demonstrated that microRNAs are expressed in a cell-specific or stage-specific manner during spermatogenesis. In this review, we focus on the roles of microRNAs in spermatogenesis. We highlight that N6-methyladenosine (m6A) is involved in the biogenesis of microRNAs and miRNA regulates the m6A modification on mRNA, and that specific miRNAs have been exploited as potential biomarkers for the male factor infertility, which will provide insightful understanding of microRNA roles in spermatogenesis. Background Male fertility is dependent upon the successful perpetuation of spermatogenesis that is a highly organized process of germ cell differentiation occurring within the seminiferous tubules in the testes. Spermatogonial stem cells (SSCs) are a subset of undifferentiated spermatogonia that are capable of self-renewal to maintain the pool of SSCs or differentiation to give rise to spermatogenic lineage, thus supporting the continuous production of spermatozoa. Spermatogenesis initiates once SSCs enter differentiation process. The spermatogonia go into the meiotic phase and become spermatocytes. After a long-lasting meiosis I, preleptotene spermatocytes transform into second spermatocytes and enter meiosis II to produce haploid round spermatids, which undergo spermiogenesis including acrosomal biogenesis, flagellum development, chromatin condensation, cytoplasmic reorganization and exclusion. Ultimately, the round spermatids transform into spermatozoa, which are released into the lumen of seminiferous tubules. This highly organized spermatogenesis requires accurate, spatial and temporal regulation of gene expression governed by transcriptional, post-transcriptional and epigenetic processes. More than a thousand of protein coding genes that are involved in the spermatogenesis have been identified. However, the mechanisms that mediate the expression of these spermatogenesis-related genes have not been fully uncovered. The microRNAs (miRNAs, miR), small (~22 nucleotides) single-strand noncoding RNAs, are linked to cell proliferation, differentiation and apoptosis. Transcriptome data indicate that miRNAs are extensively transcribed during spermatogenesis. The miRNAs are differentially expressed in a cellspecific and step-specific manner (, Chen et al. unpublished data). Some miRNAs are specifically expressed in certain type of male germ cells, while the others are universally expressed among different types of cells in the testes. Growing evidences have showed that the miRNAs are essential for male germ cell development and differentiation. A few recent reviews have reported the roles of miRNAs in spermatogenesis and fertility. In this article, we briefly summarize the most recent progress of miRNAs in the regulation of spermatogenesis. miRNA biogenesis At present, there are 1881 miRNA loci having been annotated in the human genome in the miRNA database (http://www.mirbase.org). Analysis has revealed that 1% of the human genome is miRNA genes, of which about half of miRNA genes located in the introns (intronic miRNAs) of host genes. However, some intronic miRNAs exhibit low correlated expression level with their host genes. It is likely these miRNAs are transcribed from unique transcription units independent of host genes. The biogenesis of miRNAs is modulated at a few levels, including miRNA transcription, processing by Drosha and Dicer, RNA methylation, uridylation and adenylation ( Fig. 1). The initial transcripts are termed the primary miRNAs (pri-miRNAs) that are variable in length from several hundreds to thousands of nucleotides. The pri-miRNAs are methylated by the methyltransferase like 3 (METTL3), marking them for recognition and processing by the DiGeorge syndrome critical region 8 (DGCR8). The pri-miRNAs are thus processed by drosha ribonuclease III (Drosha) and its cofactor DGCR8 into~70 nucleotides (nt) long miRNA precursor (pre-miRNAs). The pre-miRNAs are then transported into the cytoplasm by exportin 5 (EXP5) in accompanied with Ran-GTP and cleaved by Dicer into~22 base pair (bp) double-strands RNAs (dsRNAs). These dsRNAs are loaded onto an Argonaute protein (AGO) so as to form miRNA-induced silencing complex (miRISC), in which one strand of the~22-nt RNA duplex remains in AGO as a mature miRNA, whereas the other strand is degraded. Interestingly, Alarcon et al. recently reported that RNA-binding protein heterogeneous nuclear ribonucleoprotein A2/B1 (HNRNPA2B1) binds m6A-bearing pri-miRNAs, interacts with DGCR8 and thus facilitates the processing of pri-miRNAs. In consistent with this, loss of HNRNPA2B1 or depletion of METTL3 led to concomitant accumulation of unprocessed pri-miRNAs and decrease of the global mature miRNAs. Therefore, the methylation mark acts as a key posttranscriptional modification that enhances the initiation of miRNA biogenesis. Mechanisms of miRNA action Usually, a specific base-pairing between miRNAs and mRNAs induces mRNA degradation or translational repression. In mammals, the overall complementarity between a miRNA and its target is usually imperfect, which allows each miRNA to potentially regulate multiple RNAs. It is estimated that one miRNA may target as many as 400 genes on average. Conversely, the expression of a single gene can also be modulated by multiple miRNAs. Interestingly, it has been reported recently that miR-NAs regulate the m6A modification in mRNAs via a sequence pairing mechanism. As a result, manipulation of miRNA expression leads to change of m6A modification through modulating the binding of METTL3 to mRNAs ( Fig. 1). The m6A modification, in turn, modulates mRNA metabolism and thus is another key posttranscriptional control of gene expression. Evidences have indicated that m6A methylation determines stem cell fate by regulating pluripotent transition toward differentiation. Intriguingly, deficiency of ALKBH5, a m6A demethylase, leads to aberrant spermatogenesis and apoptosis in mouse testis through the demethylation of m6A on mRNAs. Functions of miRNAs in spermatogenesis Conditional Dicer knockout mouse models The overall importance of miRNA signaling for regulation of spermatogenesis has been demonstrated using conditional knockout of Dicer in germ cells. Dicer1 ablation in prospermatogonia just before birth using Ddx4 promoter-driven Cre expression led to an alteration in meiotic progression, significant increase of apoptosis in pachytene spermatocytes, a reduced number of round spermatids and morphological defects in spermatozoa. Moreover, Ngn3 is expressed endogenously in type A spermatogonia starting from postnatal d 5. In the mouse model of selective deletion of Dicer1 in type A spermatogonia by Ngn3 promoter-driven Cre, the first clear defects were displayed in haploid round spermatids. The spermiogenesis was severely compromised. Similarly, conditional depletion of Dicer1 using the Stra8Cre transgene in early spermatogonia resulted in the comparable phenotype to the Ngn3Cre-driven Dicer1 deletion. In addition, deletion of Dicer1 in haploid spermatids using the protamine 1 (Prm1)-Cre transgene led to abnormal morphology in the elongated spermatids and spermatozoa. But, the Prm1Cre-Dicer1 knockout caused a less severe phenotype compared to those in which Dicer1 was deleted from prospermatogonia and spermatogonia. Collectively, the earlier the ablation of Dicer occurs, the more severe side effects on spermatogenesis are found. Therefore, miRNA-mediated post-transcriptional control is an important regulator for spermatogenesis. The roles of miRNAs in SSC self-renewal and differentiation SSCs are the foundation of spermatogenesis that involves a delicate balance between self-renewal and differentiation of SSCs to ensure the lifelong production of spermatozoa. In the testes, the SSCs reside in a unique microenvironment or 'niche'. The niche factor glial cell line-derived neurotropic factor (GDNF) is the first welldefined paracrine factor that promotes SSC self-renewal. GDNF signaling acts via the RET tyrosine kinase and requires a ligand-specific co-receptor GFR1 in mouse SSCs. Evidences have shown that through the PI3K/AKT-dependent pathway or the SRC family kinase (SFK) pathway, GDNF regulates the expression of the transcription factors B cell CLL/ lymphoma 6 member B (BCL6B), ETS variant 5 (ETV5), DNA-binding protein 4 (ID4), LIM homeobox 1 (LHX1) and POU class 3 homeobox 1 (POU3F1) to drive SSC self-renewal. miRNAs conduce maintenance of the pool of SSCs. It has been shown that miR-20 along with miR-21, −34c, −135a, −146a, −182, −183, −204, −465a-3p, −465b-3p, −465c-3p, −465c-5p and −544 were preferentially expressed in the SSC-enriched population (Fig. 2). Importantly, miR-20, miR-21 and miR-106a contribute to maintenance of mouse SSC homeostasis. Fig. 2 The expression of associate miRNAs in testicular cells miR-135a mediates the maintenance of rat SSCs by regulating FOXO1 that promotes high levels of Ret protein on the cell surface of SSCs. Moreover, miR-544 regulates self-renewal of goat SSCs by targeting the promyelocytic leukemia zinc finger gene (PLZF), which is the first transcription factor to be identified as being involved in SSC self-renewal. Similarly, miR-224 regulates mouse SSC self-renewal via modulating PLZF and GFR1. Interestingly, miR-34c is expressed in goat SSCs and promotes SSC apoptosis in a p53-depemdent manner. Recently, it was found that miR-204 was involved in the regulation of dairy goat SSC proliferation via targeting Sirt1. Collectively, miRNAs are involved in regulating SSCs fate. The roles of miRNAs in meiosis and spermiogenesis Growing evidences have also demonstrated that specific miRNAs regulate meiosis (Fig. 2). The expression of miR-449 cluster is abundant and is upregulated upon meiotic initiation during testis development and in adult testes. The expression pattern of the miR-449 cluster is similar to that of miR-34b/c. Moreover, miR-34b/c and miR-449 cluster share the same seed region and thus target same sets of mRNAs. Depletion of either miR-34 cluster or miR-449 cluster displays no apparent defect in male germ cell development. However, simultaneous knockout of these two clusters led to sexually dimorphic and infertility, suggesting that miR-34b/c and the miR-449 cluster function redundantly in the regulation of spermatogenesis. Furthermore, miR-18, one of the miR-17-92 cluster, is abundantly expressed in spermatocytes. miR-18 targets heat shock factor2 (Hsf2), which is a critical transcription factor for spermatogenesis. Finally, miR-34b-5p regulates meiotic progression by targeting Cdk6. A unique chromatin remodelling occurs during spermatogenesis when histones are replaced by DNA packing proteins, such as transition proteins (TPs) and protamines (PRMs), which are exclusive to male germ cells. In the post-mitotic germ cells, the timely expression of TPs and PRMs is prerequisite for compaction and condensation of chromatin during spermiogenesis. To secure this timed expression pattern, Tp and Prm are subjected to an efficiently post-transcriptional control. It has been demonstrated that miR-469 suppresses the translation of TP2 and PRM2 by targeting mRNA of Tp2 and Prm2 in pachytene spermatocytes and round spermatids. On the contrary, miR-122a that is abundantly expressed in late-stage male germ cells reduces the Tp2 mRNA expression by RNA cleavage. Although the majority of miRNAs disappear during spermiogenesis, the sperm born miRNAs have also been demonstrated to play important roles. miR-34 is present in mouse spermatozoa and zygotes but not in the oocytes or in embryos beyond the one-cell stage. Upon fertilization, miR-34c is transferred from spermatozoa to zygote where it reduces the expression of Bcl-2 and p27, leading to S-phase entry and the first cleavage. Moreover, injection of miR-34c inhibitor into the zygotes inhibits DNA synthesis and suppresses the first cleavage division, suggesting that the sperm-borne miR-34c is required for zygote cleavage. In addition, dysregulation of miR-424/322 induces DNA double-strand breaks in spermatozoa. Importantly, a set of sperm miRNAs are differentially expressed in asthenozoospermic and oligoastheno-zoospermic males compared with normozoospermic males. Furthermore, miR-151a-5p is abundant in severe asthenozoospermia cases compared with healthy controls and participates in mitochondrial biological functions. Therefore, specific miRNAs have been exploited as potential biomarkers for male factor infertility.. The extrinsic factors derived from these somatic cells trigger specific events in germ cells that dictate or influence spermatogenesis. It has been shown that miRNAs are highly abundant in Sertoli cells (Fig. 2). MiR-133b and miR-202 are involved in pathogenesis of azoospermia or Sertolicell-only syndrome. Importantly,conditional depletion of Dicer1 from Sertoli cells, using the Anti-Mllerian hormone (Amh) promoter-driven Cre in mice, results in disrupted spermatogenesis and progressive testis degeneration, indicating that miRNAs in Sertoli cells play critical roles in spermatogenesis. Specifically, miR-133b promotes the proliferation of human Sertoli cells by targeting GLI3 and mediating expression of Cyclin B1 and Cyclin D1. Moreover, miR-762 promotes porcine immature Sertoli cell growth via the ring finger protein 4 (RNF4). Spermatogenesis is supported by the testicular Sertoli cells, peritubular myoid (PTM) cells and Leydig cells FSH and androgens are fundamentally important for spermatogenesis. To elucidate the molecular mechanisms by which FSH and androgen act in the Sertoli cells, Nicholls et al. investigated the expression and regulation of micro-RNAs (miRNAs). The authors have found that a subset of miRNAs were upregulated after hormone suppression in rat model and in vitro culture of primary rat Sertoli cells. Interestingly, Pten, an intracellular phosphatase, and Eps15, a mediator of endocytosis, were down-regulated by the withdrawal of hormones. In consistent with it, overexpression of miR-23b in vitro resulted in decreased translation of PTEN and EPS15 protein. Similarly, by using androgen suppression and androgen replacement, Chang et al. identified that androgen regulated the expression of several microRNAs in mouse Sertoli cells. One of the miRNAs targets found in this study is desmocollin-1 (Dsc1), which plays an essential role in cell-cell adhesion in epithelial cells. On the other hand, elevated estradiol level is associated with male infertility. Evidences indicate that estradiol regulates proliferation of Sertoli cells in a dose-dependent manner, in which miR-17 family and miR-1285 are involved in the regulation. Collectively, miRNA transcription is a new paradigm in the hormone dependence of spermatogenesis. Leydig cells are responsible for androgen production that is essential for sperm production. Basic fibroblast growth factor (bFGF) promotes the development of stem Leydig cells and inhibits LH-stimulated androgen production by regulating miRNAs. Interestingly, miR-140-5p/140-3p control mouse Leydig cell numbers in the developing testis. Deletion of miR-140-5p/miR-140-3p results in an increase of number of Leydig cells, indicating that the miRNAs are likely to regulate the expression of factors produced by Sertoli cells that regulate differentiation of Leydig cells. Collectively, these findings indicate that miRNAs regulate the development and functions of Sertoli cells and Leydig cells, which create the niche for SSCs and thus provide structural and nutritional support for germ cells. Therefore, miRNAs in somatic cells play important roles in spermatogenesis. Conclusion and perspectives Extensive and accurate regulation of gene expression is prerequisite for spermatogenesis. miRNAs are expressed in a cell-specific or stage-specific manner during spermatogenesis. However, the roles and underlying mechanisms of many of those miRNAs in spermatogenesis remain largely unknown. Future studies should primarily focus on uncovering the roles of germ-cell specific miR-NAs in spermatogenesis. The powerful single-cell small RNA sequencing would help to more accurately profile the miRNAs for certain type of germ cells. Meanwhile, the establishment of long-term culture of SSCs and in vitro induction of differentiation of male germ cells make it possible to elucidate the role of a certain miRNA or miRNA cluster in vitro. The application of CRISPR/ Cas9 system and conditional knockout strategies would speed up the understanding of miRNA functions. Secondly, growing evidences have been demonstrated that some specific miRNAs are preferentially expressed in testicular somatic cells. But it is not clear whether these miRNAs act as secreted paracrine factors in the SSC niche, or whether they indirectly mediate the secretion of growth factors, GDNF for instance, which then affect germ cells. More somatic cell expressed miRNAs are needed to be functionally characterized. Thirdly, it has been demonstrated that some transcription factors promote SSC self-renewal (for example, BCL6B, BRACHY-URY, ETV5, ID4, LHX1, and POU3F1), while several transcription factors stimulate spermatogonia differentiation (DMRT1, NGN3, SOHLH1, SOHLH2, SOX3, and STAT3). However, it is unclear which and how miRNA/miRNA cluster regulates the expression of these transcription factors. Fourthly, it has been discovered recently that RNA methylation is involved in pri-miRNA processing, opening the door for exploring RNA methylation in the biogenesis and function of the miR-NAs. Future research will pay increasing attention on the understanding of biological functions of epigenetic changes (or marks) during germ cell development. Finally, specific miRNAs in spermatozoa or seminal plasma will be exploited as potential biomarkers for male factor infertility. The annotation of the miRNAs and the elucidation of their regulating mechanisms in pathogenesis will provide insight into the etiology of male sterility and infertility. Together, uncovering these questions will shed new light on the pivotal roles of miRNA in spermatogenesis and fertility. |
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A small, aggressively cleaned and de-duped pre-training corpus for academic settings. It aims to recreate something akin to The Pile but prioritizes quality for the constrained token budget academic researchers live with.
It has seven config subsets and an eighth all subset that combines them for a total of ~91B tokens (GPT2 Tokenizer estimate). These splits are as follows:
c4_realnews: The RealNews domain subset of the C4 dataset containing news articles.openwebtext: The OpenWebText dataset containing the contents of the links mentioned in Reddit posts with at least 3 upvotes.peS2o: The PeS2o dataset containing academic articles from Semantic Scholar.redpajama_books: The books subset of RedPajama V1.stackexchange: The EN StackExchange non-code subset of the BigScience ROOTs dataset.uspto: The EN USPTO patent applications contents' subset of the BigScience ROOTs dataset.wiki: The EN Wiki subset of the BigScience ROOTs dataset.
The following processing and filtering steps have been applied:
- Removed citation text and bibliography information for academic texts.
- Ran a perplexity filter using a KenLM model trained on the EN OSCAR corpus and removed documents with a perplexity of more than 325 and less than 7.
- Removed samples which have a repeating <=4-gram proportion of 15%.
- Removed samples which have lower than 99% confidence of being EN using the lingua language detector.
- Performed an aggressive MinHash de-dupe using a shingle size of 8 and a low threshold of 0.5.
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