bluuebunny/crossref_metadata_2025 huggingface dataset:
Phylogenetic study of extirpated Korean leopard using mitochondrial DNA from an old skin specimen in South Korea
Authors: Hyun Jee Yun , Cho Jang Hyuk , Pandey Puneet , Min Mi-Sook , Kim Kyung Seok , Lee Hang
Published: May 2020

The leopard, Panthera pardus, is a threatened species in its range throughout the world. Although, historically, the Korean Peninsula had a high population density of leopards, they were extirpated from South Korea by 1970, leaving almost no genetic specimens. Traditionally, Korean leopards are classified as Panthera pardus orientalis; however, their classification is based only on locality and morphology. Therefore, there is a need for genetic studies to identify the phylogenetic status of Korean leopards at the subspecies level. Presently, no extant wild specimen is available from South Korea; therefore, we extracted genetic material from the old skin of a leopard captured in Jirisan, South Korea in the 1930s and conducted the first phylogenetic study of the South Korean leopard. A total of 726 bp of mitochondrial DNA, including segments of the NADH5 and control region, were amplified by PCR. A phylogenetic analysis of the fragment, along with sequences of nine leopard subspecies from GenBank revealed that the extinct South Korean leopard belonged to the Asian leopard group and in the same clade as the Amur leopard (Panthera pardus orientalis). Thus, the leopard that inhabited South Korea in the past was of the same subspecies as the Amur leopard population currently inhabiting the transboundary region of Russia, China, and North Korea. These results emphasize the importance of conserving the endangered wild Amur leopard population (estimated to be about 60–80 individuals) in Russia and China, for future restoration of leopards in the Korean Peninsula.
Extent, patterns and demographic correlates for physical fighting among school-attending adolescents in Namibia: examination of the 2013 Global School-based Health Survey
Authors: Davis Laura E. , Abio Anne , Wilson Michael Lowery , Shaikh Masood Ali
Published: May 2020

Background

Physical fighting is particularly detrimental for young people, often affecting other areas of their developing lives, such as relationships with friends and family and participating in risky behaviors. We aim to quantify the amount of problematic physical fighting in Namibian adolescents and identify modifiable risk factors for intervention.

Methods

We used the Namibia 2013 Global School-based Student Health Survey (GSHS). This survey collects health-related information on school-attending adolescents in grades 7 to 12. We defined physical fighting as having participated in at least two physical fights in the 12 months prior to responding to the survey. Factors that may be associated with physical fighting were identified a prior based on the literature and included age, sex, anxiety, suicide planning, truancy, physical activity, bullying victimization, presence of supportive parental figures, presence of helpful peers, extent of social network, and food insecurity. Multivariable logistic regression models were created to identify factors associated with physical fighting.

Results

A total of 4,510 adolescents were included in the study. A total of 52.7% female. 16.9% of adolescents reported engaging in at least two physical fights in the previous year. Factors associated with an increased odds of physical fighting included having a suicide plan, anxiety, truancy, food deprivation and being bullied. Increased age and loneliness were associated with a decreased odds of physical fighting.

Conclusion

This study identifies problematic physical fighting among adolescents in Namibia. We recommend public health and school-based programming that simultaneously targets risk behaviours and conflict resolution to reduce rates of physical fighting.
Analyzing bacterial community in pit mud of Yibin Baijiu in China using high throughput sequencing
Authors: Chen Li , Li Yuzhu , Jin Lei , He Li , Ao Xiaolin , Liu Shuliang , Yang Yong , Liu Aiping , Chen Shujuan , Zou Likou
Published: May 2020

“Yibin Baijiu” (YB) is a special Chinese strong-aroma Baijiu (CSAB) that originated in Yibin, a city in western China. YB is fermented in cellars lined with pit mud (PM), the microbiota in which may affect YB quality. In this study, high throughput sequencing of the 16S rRNA gene was used to demonstrate the bacterial community structure and diversity in PM of YB. In addition, the physicochemical characteristics of PM were also analyzed, including moisture content, pH, and available phosphorous, ammonia nitrogen, and humic acid levels. Results showed that Firmicutes was the dominant phylum in all PM samples with abundance > 70.0%, followed by Euryarchaeota (11.3%), Bacteroidetes (6.5%), Synergistetes (3.0%), Actinobacteria (1.4%), and Proteobacteria (1.2%). Furthermore, 14 different genera with average relative abundance of > 1% were detected. The Chao1 and Shannon indexes did not vary significantly between the sub-layer and middle-layer PM (P > 0.05). However, Linear discriminant analysis Effect Size (LEfSe) analysis showed that the relative abundance of Lactobacillus in the sub-layer PM was significantly higher than in middle-layer PM. pH differed significantly (P < 0.05) between the two groups. Canonical correspondence analysis revealed that bacterial community in PM correlated significantly with available phosphorous content and pH. Our study provides basic data for further elucidating the diversity of microbiota in the PM of YB and the potential mechanism of Baijiu production.
High type I collagen density fails to increase breast cancer stem cell phenotype
Authors: Valadão Iuri C. , Ralph Ana Carolina L. , Bordeleau François , Dzik Luciana M. , Borbely Karen S.C. , Geraldo Murilo V. , Reinhart-King Cynthia A. , Freitas Vanessa M.
Published: May 2020

Breast cancer is a highly frequent and lethal malignancy which metastasis and relapse frequently associates with the existence of breast cancer stem cells (CSCs). CSCs are undifferentiated, aggressive and highly resistant to therapy, with traits modulated by microenvironmental cells and the extracellular matrix (ECM), a biologically complex and dynamic structure composed mainly by type I collagen (Col-I). Col-I enrichment in the tumor-associated ECM leads to microenvironment stiffness and higher tumor aggressiveness and metastatic potential. While Col-I is also known to induce tumor stemness, it is unknown if such effect is dependent of Col-I density. To answer this question, we evaluated the stemness phenotype of MDA-MB-231 and MCF-7 human breast cancer cells cultured within gels of varying Col-I densities. High Col-I density increased CD44+CD24− breast cancer stem cell (BCSC) immunophenotype but failed to potentiate Col-I fiber alignment, cell self-renewal and clonogenicity in MDA-MB-231 cells. In MCF-7 cells, high Col-I density decreased total levels of variant CD44 (CD44v). Common to both cell types, high Col-I density induced neither markers related to CSC nor those related with mechanically-induced cell response. We conclude that high Col-I density per se is not sufficient to fully develop the BCSC phenotype.
Multivariate Study of the Use of Assessment Strategies and Cross Cutting Issues by Basic School Teachers: The Case of Ghana’s New Curriculum
Authors: Senyefia Bosson-Amedenu , Eunice Osei-Asibey , Joseph Acquah
Published: May 2020

Ghana’s new basic school curriculum requires teachers to use new teaching strategies that also address cross cutting issues in their teaching to enhance learning. This study sought to assess the use of assessment strategies by basic school teachers in Ghana. A sample size of 100 was computed at 95% confidence interval and randomly selected from the population. The features, strategies and principles underpinning the assessment strategies and cross cutting issues in Ghana’s new curriculum for the basic school formed the basis of the construction of the 47 items used in the questionnaire. The internal consistency of the items used in the four point likert scale was high with Cronbach’s Alpha coefficient of 0.995. Principal component analysis and multiple linear regressions were the main methods used for the analysis.KMO statistic of 0.921 and Bartlett’s Test’s Chi Square value was13684.049 with difference of freedom of 1081 and significance at 0.00000. Multiple extraction approaches were used to retain two components which explained about 91% of the variance. The first component named Criterion motivation explained about 61.7% of the variance and composed generally of assessment as-of- and - for learning strategies. The second component which was named inclusion motivation, generally loaded highly with the cross cutting issues and explaining about 28.6% of the total variance. Criterion and inclusion motivation were found to predict feedback with a high power of 94%.Criterion motivation was found to have a positive impact on feedback received from students and was statistically significant (B = 0.746, P<0.001). Again, there was a positive relationship between the inclusion motivation and feedback with a significant difference (B = 0.232, P<0.001).There were some disparities in the use of assessment strategies outlined in the new basic school curriculum for Ghana. Teachers were found to exhibit preference to some components of the assessment strategies recommended for use in the new curriculum at the detriment of others. It is recommended that the developed criterion motivation and inclusive motivation approaches are adopted in teaching in order to enhance maximum feedback from learners.
Biological and Physico-chemical Properties of Causal Agent of Virus Disease of Coccinia barteri (Hook. f.) Keay in Calabar, Cross River State
Authors: Uyoh V. E. , Umoh O. T. , Toby A. T. , Umoden O. M.
Published: May 2020

The physico-chemical properties of the causal agent of virus disease of Coccinia barteri (Hook. f.) Keay were studied. The virus causing the disease was characterized using diagnostic tools such as host range, longevity in vitro, thermal inactivation point, dilution endpoint and aphid transmission. The virus was mechanically transmitted from the natural host (C. barteri) to the healthy test plants in the green house. In the biological properties, the virus was successfully transmitted by Aphis spiraecola (obtained from Chromolaena odorata (L.) R. M. King & H. Rob.) from infected Cucumeropsis mannii Naudin to a healthy C. mannii in a non-persistent manner and had a narrow host range limited to the family Cucurbitaceae. In the physico-chemical properties based on crude sap with an unknown virus concentration, beyond which infectivity was lost. It was readily inactivated by heating to 35 – 65°C for 10 minutes in determination of thermal inactivation point. The virus had a longevity in vitro of between 4 – 5 days beyond which it was non-infectious. Symptoms induced by the virus were leaf cupping, mottle chlorosis, blisters, stunted growth, rugosity, leaf malformation and mosaic patterns.
CD24 blunts the sensitivity of retinoblastoma to vincristine by modulating autophagy
Authors: Sun Jie , Feng Dongju , Xi Huiyu , Luo Jiajing , Zhou Zewei , Liu Qinghuai , Chen Yun , Shao Qing
Published: May 2020

Retinoblastoma (RB) is the most common childhood malignant intraocular tumor. The clinical efficacy of vincristine (VCR) in the treatment of RB is severely limited by drug resistance. Here, we found that CD24, a GPI‐anchored protein, was overexpressed in human RB tissues and RB cell lines, and was associated with the sensitivity of RB cells in response to VCR therapy. We demonstrated that CD24 plays a critical role in impairing RB sensitivity to VCR via regulating autophagy. Mechanistically, CD24 recruits PTEN to the lipid raft domain and regulates the PTEN/AKT/mTORC1 pathway to activate autophagy. Lipid raft localization was essential for CD24 recruitment function. Collectively, our findings revealed a novel role of CD24 in regulating RB sensitivity to VCR and showed that CD24 is a potential target for improving chemotherapeutic sensitivity and RB patient outcomes.
Modeling EV Kinetics for Use in Early Cancer Detection
Authors: Ferguson Scott , Weissleder Ralph
Published: May 2020

Tumor‐derived extracellular vesicles (EVs) represent promising biomarkers for monitoring cancers. Technological advances have improved the ability to measure EV reliably in blood using protein, RNA, or lipid detection methods. However, it is less clear how efficacious current EV assays are for the early detection of small and thus curable tumors. Here, a mathematical model is developed to estimate key parameter values and future requirements for EV testing. Tumor volumes in mice correlate well with increases in total number of circulating EV allowing the researchers to calculate EV shed rates for four different published cancer models. Model extrapolations to human physiology show good agreement with published clinical data. Specifically, it is shown that current bulk EV detection systems are ≈104‐fold too insensitive to detect human cancers of ≈1 cm3. Conversely, it is predicted that emerging single EV methods will allow blood‐based detection of cancers of <1 mm3 in humans.
Palladium(II)‐Catalyzed Direct Access to Indeno[1,2‐c]isochromen‐5(11H)‐Ones via Intramolecular Oxypalladation‐Initiated Cascade Process
Authors: Karuppasamy Muthu , Vachan B. S. , Jandial Tanvi , Babiola Annes Sesuraj , Bhuvanesh Nattamai , Uma Maheswari C. , Sridharan Vellaisamy
Published: May 2020

A palladium(II)‐catalyzed cascade approach was established for the synthesis of indeno[1,2‐c]isochromen‐5(11H)‐ones starting from 2‐alkynyl tert‐butyl benzoates bearing a pendant α,β‐unsaturated carbonyl moiety in high yields (up to 99%) under mild conditions. This strategy offered high atom and step economy by delivering isobutene as the only side product, and by generating two new bonds and two rings in a single synthetic operation. The mechanism of the cascade process was visualized comprising sequential intramolecular oxypalladation (6‐endo‐dig), intramolecular olefin insertion, and protonation steps.

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Metformin Restores Tetracyclines Susceptibility against Multidrug Resistant Bacteria
Authors: Liu Yuan , Jia Yuqian , Yang Kangni , Li Ruichao , Xiao Xia , Zhu Kui , Wang Zhiqiang
Published: May 2020

Highly persistent incidence of multidrug resistant (MDR) bacterial pathogens constitutes a global burden for public health. An alternative strategy to alleviate such a crisis is to identify promising compounds to restore antibiotics activity against MDR bacteria. It is reported that the antidiabetic drug metformin exhibits the potentiation effect on tetracycline antibiotics, particularly doxycycline and minocycline, against MDR S. aureus, E. faecalis, E. coli, and S. enteritidis. Mechanistic studies demonstrate that metformin promotes intracellular accumulation of doxycycline in tetracycline‐resistant E. coli. In addition, metformin boosts the immune response and alleviates the inflammatory responses in vitro. Last, metformin fully restores the activity of doxycycline in three animal infection models. Collectively, these results reveal the potential of metformin as a novel tetracyclines adjuvant to circumvent MDR bacterial pathogens and to improve the treatment outcome of recalcitrant infections.
Energetics and Energy Loss in 2D Ruddlesden–Popper Perovskite Solar Cells
Authors: Yang Jianming , Xiong Shaobing , Song Jingnan , Wu Hongbo , Zeng Yihan , Lu Linyang , Shen Kongchao , Hao Tianyu , Ma Zaifei , Liu Feng , Duan Chungang , Fahlman Mats , Bao Qinye
Published: May 2020

2D Ruddlesden–Popper perovskites (RPPs) are emerging as potential challengers to their 3D counterpart due to superior stability and competitive efficiency. However, the fundamental questions on energetics of the 2D RPPs are not well understood. Here, the energetics at (PEA)2(MA)n−1PbnI3n+1/[6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) interfaces with varying n values of 1, 3, 5, 40, and ∞ are systematically investigated. It is found that n–n junctions form at the 2D RPP interfaces (n = 3, 5, and 40), instead of p–n junctions in the pure 2D and 3D scenarios (n = 1 and ∞). The potential gradient across phenethylammonium iodide ligands that significantly decreases surface work function, promotes separation of the photogenerated charge carriers with electron transferring from perovskite crystal to ligand at the interface, reducing charge recombination, which contributes to the smallest energy loss and the highest open‐circuit voltage (Voc) in the perovskite solar cells (PSCs) based on the 2D RPP (n = 5)/PCBM. The mechanism is further verified by inserting a thin 2D RPP capping layer between pure 3D perovskite and PCBM in PSCs, causing the Voc to evidently increase by 94 mV. Capacitance–voltage measurements with Mott–Schottky analysis demonstrate that such Voc improvement is attributed to the enhanced potential at the interface.
Sustainable Engaged Accountable Learners
Authors: Gisondi Michael A. , Branzetti Jeremy , Hopson Laura R. , Regan Linda
Published: May 2020

The development of lifelong learners is among the most challenging goals for medical educators. The authors identify two important scholarly works that profoundly altered their understanding and approach to lifelong learning and curriculum design: L. Dee Fink’sTaxonomy of Significant Learningand Cutrer et al.’sMaster Adaptive Learnermodel. By applying these guides to their teaching and related research, three important characteristics of lifelong learning became evident: sustainability, engagement, and accountability. These are abbreviated “SEALs,” for sustainable engaged accountable learners. This paper defines these qualities as they relate to emergency medicine training, significant learning, and the development of adaptive expertise. Connections to Fink’s and Cutrer’s works are offered for each learner characteristic. Educational and psychological theories that support the SEALs model are paired with practical suggestions for educators to promote these desired qualities in their trainees. Relevant features of adult learning are highlighted, including self‐regulation, motivation, agency, and autonomy.
Determination and correlation of temperature and pH value dependent solubility of dl‐methionine
Authors: Chen Zhirong , Zhou Rongfan , Yin Hong , Yuan Shenfeng
Published: May 2020

In order to provide basic data for the crystallization of dl‐methionine and understand the thermodynamic properties of dissolution, the solubility of dl‐methionine in water was measured by gravimetric method from 294.05 to 347.05 K and the solubility at different pH values under temperature 302.95 to 342.05 K was determined by elemental analysis in this work. The experimental data show that the solubility of dl‐methionine increases with increasing temperature as well as more acidic or basic pH values. The van't Hoff equation, modified Apelblat equation, λh equation, Wilson model, NRTL model, and UNIQUAC model were used to correlate the solubility data versus temperature. The melting temperature, enthalpy of fusion, enthalpy and entropy of dissolution were estimated from solubility data and it shows that the expression of solubility by enthalpy and entropy of dissolution gives more reasonable estimation and Wilson model gives a better correlation for these thermodynamic properties.
Precision Molecular Threading/Dethreading
Authors: Groppi Jessica , Casimiro Lorenzo , Canton Martina , Corra Stefano , Jafari‐Nasab Mina , Tabacchi Gloria , Cavallo Luigi , Baroncini Massimo , Silvi Serena , Fois Ettore , Credi Alberto
Published: May 2020

The general principles guiding the design of molecular machines based on interlocked structures are well known. Nonetheless, the identification of suitable molecular components for a precise tuning of the energetic parameters that determine the mechanical link is still challenging. Indeed, what are the reasons of the “all‐or‐nothing” effect, which turns a molecular “speed‐bump” into a stopper in pseudorotaxane‐based architectures? Here we investigate the threading and dethreading processes for a representative class of molecular components, based on symmetric dibenzylammonium axles and dibenzo[24]crown‐8 ether, with a joint experimental–computational strategy. From the analysis of quantitative data and an atomistic insight, we derive simple rules correlating the kinetic behaviour with the substitution pattern, and provide rational guidelines for the design of modules to be integrated in molecular switches and motors with sophisticated dynamic features.
Direct Umpolung Morita–Baylis–Hillman like α‐Functionalization of Enones via Enolonium Species
Authors: Arava Shlomy , Santra Sourav K. , Pathe Gulab K. , Kapanaiah Raja , Szpilman Alex M.
Published: May 2020

Herein we report on the umpolung of Morita–Baylis–Hillman type intermediates and application to the α‐functionalization of enone C−H bonds. This reaction gives direct access to α‐chloro‐enones, 1,2‐diketones and α‐tosyloxy‐enones. The latter are important intermediates for cross‐coupling reaction and, to the best of our knowledge, cannot be made in a single step from enones in any other way. The proposed mechanism is supported by spectroscopic studies. The key initial step involves conjugate attack of an amine (DABCO or pyridine), likely assisted by hypervalent iodine acting as a Lewis acid leading to formation of an electrophilic β‐ammonium‐enolonium species. Nucleophilic attack by acetate, tosylate, or chloride anion is followed by base induced elimination of the ammonium species to give the noted products. Hydrolysis of α‐acetoxy‐enones lead to formation of 1,2‐diketones. The α‐tosyl‐enones participate in Negishi coupling reactions under standard conditions.
DNA Nanolithography Enables a Highly Ordered Recognition Interface in a Microfluidic Chip for the Efficient Capture and Release of Circulating Tumor Cells
Authors: Zhang Jialu , Lin Bingqian , Wu Lingling , Huang Mengjiao , Li Xingrui , Zhang Huimin , Song Jia , Wang Wei , Zhao Gang , Song Yanling , Yang Chaoyong
Published: May 2020

Microfluidic chips with nano‐scale structures have shown great potential, but the fabrication and cost issues restrict their application. Herein, we propose a conceptually new “DNA nanolithography in a microfluidic chip” by using sub‐10 nm three‐dimensional DNA structures (TDNs) as frameworks with a pendant aptamer at the top vertex (ApTDN‐Chip). The nano‐scale framework ensures that the aptamer is in a highly ordered upright orientation, avoiding the undesired orientation or crowding effects caused by conventional microfluidic interface fabrication processes. Compared with a monovalent aptamer modified chip, the capture efficiency of ApTDN‐Chip was enhanced nearly 60 % due to the highly precise dimension and rigid framework of TDNs. In addition, the scaffolds make DNase I more accessible to the aptamer with up to 83 % release efficiency and 91 % cell viability, which is fully compatible with downstream molecular analysis. Overall, this strategy provides a novel perspective on engineering nano‐scaffolds to achieve a more ordered nano‐topography of microfluidic chips.
Complementing Pyridine‐2,6‐bis(oxazoline) with Cyclometalated N‐Heterocyclic Carbene for Asymmetric Ruthenium Catalysis
Authors: Li Long , Han Feng , Nie Xin , Hong Yubiao , Ivlev Sergei , Meggers Eric
Published: May 2020

A strategy for expanding the utility of chiral pyridine‐2,6‐bis(oxazoline) (pybox) ligands for asymmetric transition metal catalysis is introduced by adding a bidentate ligand to modulate the electronic properties and asymmetric induction. Specifically, a ruthenium(II) pybox fragment is combined with a cyclometalated N‐heterocyclic carbene (NHC) ligand to generate catalysts for enantioselective transition metal nitrenoid chemistry, including ring contraction to chiral 2H‐azirines (up to 97 % ee with 2000 TON) and enantioselective C(sp3)−H aminations (up to 97 % ee with 50 TON).
Synthesis, characterization, DNA binding, cytotoxicity and molecular docking properties of three novel butterfly‐like complexes with nitrogen‐containing heterocyclic ligands
Authors: Gao Enjun , Li Zhipeng , Zhu Xiaopeng , Ma Zhiyan , Zhu Mingchang
Published: May 2020

Three novel complexes, namely [Nd·L1·HCOO·(H2O)4] (1), [Pr·L1·HCOO·(H2O)4] (2) and [In·L2·Cl·(H2O)2] (3) (L1 = 1,1‐bis(5‐(pyrazin‐2‐yl)‐1,2,4‐triazol‐3‐yl)methane, L2 = 1,1‐bis(5‐(pyrazin‐2‐yl)‐1,2,4‐triazol‐3‐yl)ketone), were synthesized and characterized. The molecular structures of 1–3 were confirmed using single‐crystal X‐ray diffraction. All three obtained complexes are zero‐dimensional and connected to each other by hydrogen bonds. In 1 and 2 the metal is surrounded by nine donors and 3 has seven coordination sites. The interaction of 1–3 with calf thymus DNA (CT‐DNA) was explored using UV absorption spectra and fluorescence spectra. The intrinsic binding constants of 1–3 with CT‐DNA are about 1.9 × 104, 1.4 × 104 and 1.1 × 104, respectively. Stern–Volmer quenching plots of 1–3 have slopes of 0.1508, 0.134 and 0.1205, respectively. The ability of these complexes to cleave pBR322 plasmid DNA was demonstrated using gel electrophoresis assay. Apoptosis studies of the three novel complexes showed a significant inhibitory effect on HeLa cells. Furthermore, MTT assays were used to evaluate the anticancer activity of the three complexes. The cytotoxicity study indicated that complex 1 possesses a higher inhibitory rate of HeLa cells than the other complexes. Especially, the efficacy of 1 was shown to be the highest for cisplatin at 24 h. A further molecular docking technique was introduced to understand the binding of the complexes toward the target DNA.
Synthesis and structural characterization of oxovanadium(IV) complexes of dimedone derivatives
Authors: Al‐Hazmi Gamil A.A. , Abou‐Melha Khlood S. , Althagafi Ismail , El‐Metwaly NashwaM. , Shaaban Fathy , Abdul Galil Mansour S. , El‐Bindary Ashraf A.
Published: May 2020

We have successfully synthesized new oxovanadium (IV) complexes with dimedone derivatives and their structure were confirmed by elemental analyses, spectroscopic techniques (FT‐IR, UV–visible, EPR) and thermal analysis. The reaction of [VO (acac)2] with the azo dimedone ligands (HLn) produced mononuclear oxovanadium (IV) complexes with formula [VO (Ln)2]H2O. Results of the molar conductance proved that VO2+ complexes are non‐electrolytes and fall in the range 14–16 Ω‐1cm2mol−1. The coordination geometry of VO (IV) complexes is square‐pyramidal, where vanadium (IV) ion is coordinated by oxygen atom of the carbonyl (C=O) group, and nitrogen atom of the deprotonating hydrazone moiety (–NH–), while the fifth position is occupied by an oxo group. Moreover, the optimized structure, bond angles, bond lengths, as well as the calculated quantum chemical parameters of the complexes have been estimated. DNA binding activities of the complexes were investigated using electronic absorption titration and viscosity measurements. The obtained results showed groove binding of the complexes to CT‐DNA accompanied with a partial insertion of the ligand between the base stacks of the DNA with a binding constant of 2.07–5.51 x 105 M−1 range. Evaluation results of the synthesized complexes against the human cancer cell lines HepG‐2 and MCF‐7, as compared to the positive controls in the viability assay of vinblastine and colchicine have been reported. The in vitro anti‐oxidant activity of all the complexes is determined by DPPH free radical‐scavenging assay. Finally, the anti‐microbial activities of the complexes have been investigated against fungal (Candida albicans), gram negative bacteria (Escherichia coli), and gram positive bacteria (Staphylococcus aureus) using the disc‐diffusion method.
Epoxy‐based composite adhesives with improved lap shear strengths at high temperatures for steel‐steel bonded joints
Authors: Chailee Orawan , Parnklang Tewarak , Mora Phattarin , Pothisiri Thanyawat , Jubsilp Chanchira , Rimdusit Sarawut
Published: May 2020

High‐performance room temperature‐cure epoxy structural adhesives utilizing simplified formulation are developed. The developed structural adhesive consists of diglycidyl ether of bisphenol A (DGEBA) and novolac epoxy blend as a base resin, micrometer‐sized silica particles as a reinforcing filler, and triethylenetetramine as a curing agent. The developed ambient temperature‐cure epoxy structural adhesive with optimized formulation exhibits outstanding properties including high glass transition temperature of 95°C, high thermal stability with degradation temperature at 5% weight loss of 364°C, exceptionally high rubbery plateau modulus of 320 MPa, good flame‐retardant characteristics with limiting oxygen index of 40, and high single lap shear strength for single lap steel‐steel bonded joint of 548 MPa at the temperature of 80°C. The silica‐filled DGEBA/novolac epoxy composite adhesive is a potential candidate for applying as a structural adhesive for construction with long‐term durability.
A new approach to estimate the curing mode of thermosetting polymer films with regard to physical aging and slow chemical processes
Authors: Zhavoronok Elena S. , Senchikhin Ivan N.
Published: May 2020

We propose an original method to determine the temperature and time required for additional curing of physically aged partially cured glass‐shaped systems, based on the example of epoxy amine systems. The approach consists of the plotting of temperature–time–transformation (TTT) diagrams, supplemented with lines, which illustrate the shift in glass transition temperature (Tg) as a result of the processes of physical aging (enthalpy relaxation) and with isoconversion curves. Then we should determine Tg of partially cured and aged sample at a certain temperature. Having known this Tg value, the position of the isoconversion curve at a given point and Tg,∞ as well, we can determine the postcuring time at T = Tg,∞ + 5 K. Thus, the method provides information about the temperatures and the duration of these two consecutive steps. The TTT diagrams are based on experimental results obtained by differential scanning calorimetry in dynamic mode with preliminary heated samples in an external thermostat. The proposed approach based on epoxy amine systems allows the prediction of the optimal curing mode for thermosetting systems to provide the highest degree of cure. Our method is applicable to a wide range of thermosetting polymer systems that complete transition to a glassy state before full conversion is achieved.
Variation within laminae: Semi‐automated methods for quantifying leaf venation using phenoVein
Authors: Newsome Eastyn L. , Brock Grace L. , Lutz Jared , Baker Robert L.
Published: May 2020

Premise

Physiological processes may vary within leaf laminae; however, the accompanying heterogeneity in leaf venation is rarely investigated because its quantification can be time consuming. Here we introduce accelerated protocols using existing software to increase sample throughput and ask whether laminae venation varies among three crop types and four subspecies of Brassica rapa.

Methods

FAA (formaldehyde, glacial acetic acid, and ethanol)‐fixed samples were stored in ethanol. Without performing any additional clearing or staining, we tested two methods of image acquisition at three locations along the proximal‐distal axis of the laminae and estimated the patterns of venation using the program phenoVein. We developed and made available an R script to handle the phenoVein output and then analyzed our data using linear mixed‐effects models.

Results

Beyond fixation and storage, staining and clearing are not necessary to estimate leaf venation using phenoVein if the images are acquired using a stereomicroscope. All estimates of venation required some manual adjustment. We found a significant effect of location within the laminae for all aspects of venation.

Discussion

By removing the clearing and staining steps and utilizing the semi‐automated program phenoVein, we quickly and cheaply acquired leaf venation data. Venation may be an important target for crop breeding efforts, particularly if intralaminar variation correlates with variation in physiological processes, which remains an open question.
RETRACTED:Alpinumisoflavone triggers GSDME‐dependent pyroptosis in esophageal squamous cell carcinomas
Authors: Zhang Bin , Zhu Wen‐Yong , Tian Hui , Zhang Huan‐Rong
Published: May 2020

Esophageal squamous cell carcinoma (ESCC) presents a common human malignancy in the digestive system. We aimed to explore the critical effects of alpinumisoflavone (AIF) on ESCC in vitro and in vivo. The cell counting kit‐8 assay was used to determine cell viability. Colony formation assay was employed to examine the effect of AIF on the long‐term growth of ESCC cells. Cell apoptosis was determined by flow cytometry and terminal deoxynucleotidyl transferase‐mediated dUTP nick‐end labeling assay. Cell morphologies were observed by light microscopy. The enzyme‐linked immunosorbent assay was performed to examine the lactate dehydrogenase release from AIF‐treated cells. Immunofluorescent labeling was utilized to examine AIF‐induced GSDME expression. Western blot was employed to determine the expression levels of the associated proteins. Immunohistochemistry was performed to determine the localization and expression of the associated proteins in mice tumor tissues. AIF inhibited ESCC cell viability and suppressed cell growth in a dose‐ and time‐dependent fashion. Results showed that AIF promoted apoptosis in ESCC cells. Meanwhile, our results also showed that AIF triggered pyroptotic cell death in ESCC, which was mediated by gasdermin E (GSDME) cleavage. In addition, our experiments provided experimental evidence that AIF‐induced GSDME cleavage was dependent on caspase‐3 activation. Moreover, the inhibition of GSDSE by knockdown was able to switch the form of cell death from pyroptosis to apoptosis. Furthermore, the results from the xenograft animal model also supported our findings in vitro that AIF was able to promote GSDME‐mediated pyroptotic cell death in ESCC. AIF inhibited ESCC growth in vitro and in vivo by triggering GSDME‐mediated pyroptotic cell death, which is dependent on caspase‐3 activation.
Histological, histochemical, and immunohistochemical studies of hippocampus in male New Zealand rabbits
Authors: Mazher Khaled M. , Hassan Randa M.
Published: May 2020

The present study aims to give detailed histomorphological features of the hippocampus of adult male New Zealand rabbits. Both histological and histochemical specimens were prepared to be examined microscopically by using a light microscope. The hippocampus appeared as C‐shaped hippocampal proper, dentate gyrus, and subiculum. The hippocampal proper subdivided along its length according to the density and size of its major constituent pyramidal cells into four distinct regions named Cornu Ammonis (CA1, CA2, CA3, and CA4). With the histochemical preparations, each of these regions consisted of five layers, stratum alveolus, stratum oriens, stratum pyramidale, stratum radiatum, and stratum lacunosum‐moleculare. The stratum pyramidale constituted the middle dark zone and contained the principal excitatory neurons and a few interneurons. Histochemically, the pyramidal neurons along all regions of the CA reacted positively to Grimelius silver impregnation, lead hematoxylin, Gomori's aldehyde fuchsin, aldehyde thionine, Gomori's chrome alum hematoxylin, and performic acid alcian blue stains. Immunohistochemically, the pyramidal neurons reacted positively to anti‐NSE antibodies. The dentate gyrus was formed of three distinct layers. The subiculum was formed of proper subiculum, presubiculum, and parasubiculum.
Immunohistochemical characterization of postnatal changes in cerebellar cortical cytoarchitectures in ferrets
Authors: Kamiya Shiori , Sawada Kazuhiko
Published: May 2020

We immunohistochemically characterized postnatal changes in cerebellar cortical cytoarchitectures in ferrets using markers for cerebellar cortical neurons and glial cells. Although 10 lobules of the vermis were already observed on postnatal day (PD) 4, Purkinje cells were still arrayed into two to three layers. Purkinje cells were aligned in a monolayer by PD 10 and formed mature shapes on PD 42 by developing their dendritic arbors. Parvalbumin immunostaining revealed relatively slower maturation of Purkinje cells in the Lobule X cortex than in other lobules. Basket and stellate cells emerged in the molecular layer on PDs 21 and 42, respectively. Rosette‐like arranged glutamate decarboxylase 65 and 67‐positive puncta were observed in the inner granular layer (IGL) on PD 21. Proliferating cell nuclear antigen immunostaining appeared in the outer zone of the external granular layer (EGL) containing progenitors of granular neurons on PDs 4–21. Bergmann glial processes extending vertically through the molecular layer and EGL were visible with GFAP immunostaining on PD 10 and thereafter. Their somata, aligned in the Purkinje cell layer, showed immunopositivity to Sox2 already on PD 4 and subsequently to S100 protein on PD 10. Sox2‐positive cells were found sparsely in the IGL. Few of them were NeuN positive on PD 90, predicting the possibility of adult neurogenesis. These immunohistochemical results revealed that ferrets underwent cerebellar cortical histogenesis during their postnatal life in sequences. Relatively slow development or maturation of the ferret cerebellum was revealed by the timing of the monolayer alignment and morphological maturation of Purkinje cells.
Piece‐wise control of constant electromagnetic moments for spacecraft self‐ and soft‐docking exploiting dynamics conservation
Authors: Zhang Yuan‐wen
Published: May 2020

Inter‐spacecraft electromagnetic proximity operation has many potential advantages, such as no propellant consumption and plume contamination, while providing high‐precision, continuous, reversible, synchronous, and non‐contacting control capability. In addition, with constant magnetic moment actuation, the inter‐spacecraft electromagnetic force is, in essence, a kind of conservative force and has dynamics conservation. This yields specific and targeted evolvement laws of relative motion among these actuated magnetic dipoles. Exploiting these properties, spacecraft self‐ and soft‐docking could be achieved with proper piece‐wise constant magnetic moments design, which not only improves control precision, but also reduces the demand of relative motion measurement and simplifies docking controller design. Aiming at electromagnetic spacecraft self‐ and soft‐docking controller design, this paper uses dynamic modeling and dynamics conservation analysis to derive the specific evolvement laws of relative motion between the actuated magnetic dipoles first, and then utilize these laws and corresponding dynamics conservation to design the piece‐wise constant electromagnetic moments.
Illusory trust: Kanizsa shapes incidentally increase trust and willingness to invest
Authors: Erle Thorsten M. , Zürn Michael K.
Published: May 2020

Previous research has shown that the completion of basic perceptual processes is intrinsically pleasant. In the absence of diagnostic and objective cues to trustworthiness, nondiagnostic factors such as positive affect can incidentally lead to reported and behavioral trust. On the basis of these two premises, it was tested whether positive affect from the completion of perceptual processes has implications for the formation of trust in first‐time business‐consumer interactions. We tested this hypothesis in four experiments, using the famous Kanizsa illusion as an exemplary perceptual process that has been shown to trigger positive affect. We found that participants trusted companies who featured a Kanizsa shape as their logo more than companies with closely matched logos that did not allow for the completion of a basic perceptual process. This was evident on self‐reported (Experiment 1) as well as behavioral (Experiments 2–4) measures of trust. This effect even persisted under incentivized conditions (Experiment 4) and was partially mediated by the intrinsic pleasantness of perception (Experiment 3). These findings for the first time demonstrate that positive affect is not the only consequence of perception, but rather has further trickle‐down consequences for social judgments and economic decision making. Perceptual illusions seem to elicit illusory trust. Therefore, these novel findings bear important implications not only for both logo design and marketing but also for consumer decision making.
Label‐free, chronological and selective detection of aggregation and fibrillization of amyloid β protein in serum by microcantilever sensor immobilizing cholesterol‐incorporated liposome
Authors: Taniguchi Tomoya , Shimanouchi Toshinori , Sohgawa Masayuki , Noda Minoru
Published: May 2020

To facilitate the early diagnosis of Alzheimer's disease and mild cognitive impairment patients, we developed a cantilever‐based microsensor that immobilized liposomes of various phospholipids to detect a trace amount of amyloid β (Aβ) protein, and investigated its aggregation and fibrillization on model cell membranes in human serum. Three species of liposomes composed of different phospholipids of 1,2‐dipalmtoyl‐sn‐glycero‐3‐phosphocholine (DPPC), DPPC/phosphatidyl ethanolamine and 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphorylglycerol having varied hydrophilic groups were applied, which showed different chronological interactions with Aβ(1–40) protein and varied sensitivities of the cantilever sensor, depending on their specific electrostatic charged conditions, hydrophilicity, and membrane fluidity. 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphocholine (DMPC) having short hydrophobic carbon chains confirmed to show a large interaction with Aβ(1–40) and a high sensitivity. Furthermore, the incorporation of cholesterol into DMPC was effective to selectively detect Aβ(1–40) in human serum, which effect was also checked by quartz crystal microbalance. Finally, Aβ detection of 100‐pM order was expected selectively in the serum by using the developed biosensor.
Surgery during the COVID-19 pandemic: operating room suggestions from an international Delphi process
Authors:   Welsh Surgical Research Initiative (WSRI) Collaborative, Williams Alexander , Beamish Andrew J , Brown Christopher , Robinson David , Harper Elizabeth Ryan , Mellor Katie , Hopkins Luke , Luton Oliver , James Osian , Harries Rhiannon L , Thomas Rhys , Egan Richard J , Lewis Sophie , Abdelrahman Tarig , Evans Thomas , Lewis Wyn G
Published: May 2020

Background

Operating room (OR) practice during the COVID-19 pandemic is driven by basic principles, shared experience and nascent literature. This study aimed to identify the knowledge needs of the global OR workforce, and characterize supportive evidence to establish consensus.

Methods

A rapid, modified Delphi exercise was performed, open to all stakeholders, informed via an online international collaborative evaluation.

Results

The consensus exercise was completed by 339 individuals from 41 countries (64·3 per cent UK). Consensus was reached on 71 of 100 statements, predominantly standardization of OR pathways, OR staffing and preoperative screening or diagnosis. The highest levels of consensus were observed in statements relating to appropriate personal protective equipment (PPE) and risk distribution (96–99 per cent), clear consent processes (96 per cent), multidisciplinary decision-making and working (97 per cent). Statements yielding equivocal responses predominantly related to technical and procedure choices, including: decontamination (40–68 per cent), laminar flow systems (13–61 per cent), PPE reuse (58 per cent), risk stratification of patients (21–48 per cent), open versus laparoscopic surgery (63 per cent), preferential cholecystostomy in biliary disease (48 per cent), and definition of aerosol-generating procedures (19 per cent).

Conclusion

High levels of consensus existed for many statements within each domain, supporting much of the initial guidance issued by professional bodies. However, there were several contentious areas, which represent urgent targets for investigation to delineate safe COVID-19-related OR practice.
A new HPLC–DAD method for contemporary quantification of 10 antibiotics for therapeutic drug monitoring of critically ill pediatric patients
Authors: Cairoli Sara , Simeoli Raffaele , Tarchi Marco , Dionisi Marco , Vitale Alessia , Perioli Luana , Dionisi‐Vici Carlo , Goffredo Bianca Maria
Published: May 2020

The common practice of therapeutic drug monitoring (TDM) involves the quantification of drug plasma concentrations at a specific time in a dosing window. Although TDM for antibiotics is not considered mandatory, it may represent a valid tool for clinicians in order to limit antibiotic resistance and avoid therapeutic failures. The aim of our study was to develop and validate a high‐performance liquid chromatography–diode array detection method for simultaneous quantification of 10 antibiotics in plasma. This method has a fast analytical procedure that uses the same chromatographic conditions to quantify ceftazidime, ceftriaxone, meropenem, ertapenem, ciprofloxacin, tigecycline, ampicillin, levofloxacin and piperacillin, plus the β‐lactamase inhibitor tazobactam. Method validation was ensured by testing selectivity, accuracy, precision, limits of detection and quantification, recovery and stability. The calibration ranges, established accordingly to the expected plasma concentration in patients, showed a coefficient of determination >0.996 for all compounds. Within‐ and between‐days precisions reported a coefficient of variation >15%. Similarly, the accuracy evaluation reported a relative standard deviation of <10% for each antibiotic. The recovery ranged between 97 and 103% for all compounds. This method could represent a useful tool for TDM of antibiotics.
Rapid identification of chemical composition and metabolites of Pingxiao Capsulein vivousing molecular networking and untargeted data‐dependent tandem mass spectrometry
Authors: Wang Dong , Fu Zhifei , Xing Yanchao , Tan Yao , Han Lifeng , Yu Haiyang , Wang Tao
Published: May 2020

Pingxiao capsule (PXC) is a herbal medicine used for adjuvant therapy in breast cancer. However, the constituents and absorbed components of the formula and their related metabolites have not been elucidated to date. PXC is a typical traditional Chinese medicine formula consisting ofStrychnos nux‐vomicaL.,Curcuma wenyujinY. H.,Agrimonia pilosaLedeb.,Toxicodendron vernicifluum,Trogopterusdung, alumen, potassium nitrate (saltpeter) andCitrus aurantiumL. In this study, a ultra‐high performance liquid chromatography system equipped with high resolution Q‐Orbitrap mass spectrometry (MS) and comparative Global Natural Product Social molecular networking together with the Compound Discoverer software were used to identify metabolites of PXCin vitroandin vivo.Based on untargeted data‐dependent MS2and data‐mining techniques, 89 peaks of alkaloids, flavonoids, organic acid and phenolic compounds were identified in a PXC 70% methanol extract. Furthermore, 15 absorbed prototype compounds and their metabolites were rapidly confirmed in rat blood. Glucuronidation, oxidation, methylation and hydroxylation were the main metabolic pathways. We fully clarified the chemical constituents of PXC and provided a scientific and efficient strategy for rapid discovery and identification of prototypes and their metabolites in rat plasma using high‐resolution MS aided by Global Natural Product Social and Compound Discoverer software.