bluuebunny/crossref_metadata_2025 huggingface dataset:
A Compact Multifrequency Measurement System Based on an Integrated Frequency-Scanning Generator
Authors: Shi Nuannuan , Hao Tengfei , Li Wei , Li Ming
Published: November 2020

A compact multifrequency measurement system based on frequency-to-time mapping technology is proposed and experimentally demonstrated using an integrated frequency scanning signal generator. The relationship between the input microwave frequency and the time difference of a pair of pulses is established to realize the frequency information mapping to the time information. As a main part in the proposed frequency measurement system, the frequency-scanning signal is generated by heterodyning of two lasers with the monolithic integrated laser array, of which one is modulated on a saw-tooth signal. In the proposed frequency measurement system, it can measure single/multiple frequency microwave signals with a large bandwidth for high resolution and flexible tunable measurement range for multifrequency band. In the experimental demonstration, the single frequency measurement errors are less than 90 MHz within the measurement range from 4 to 12 GHz. For two-tone signal, the measurement resolution reaches about 150 MHz.
“Pull-through” Resection for Total and Subtotal Glossectomy Involving the Posterior Third of Tongue
Authors: Della Monaca Marco , Terenzi Valentina , Raponi Ingrid , Priore Paolo , Battisti Andrea , Cassoni Andrea , Nocini Riccardo , Tenore Gianluca , Brauner Edoardo , Romeo Umberto , Polimeni Antonella , Valentini Valentino
Published: November 2020

The lower lip-splitting incision associated with different types of mandibulotomy, in order to obtain wide access to total or subtotal glossectomy, is described. In those cases, high rates of functional and aesthetic deficit and postoperative morbidity (more in cases of patients in which adjuvant radiotherapy has been performed) are described. We present our experience in the treatment of patients undergoing total or subtotal glossectomy and contemporary reconstruction with flaps, and without lip-splitting incision and mandibulotomy. Materials and Methods: Data about patients affected by malignant tumors requiring total or subtotal (posterior third of the tongue) resection that were treated at our department from January 2004 to December 2014 were retrospectively reviewed. Data evaluated included: T and N stage, resection margins, operation time, and post-operative complications, such as fistula and flap necrosis. Results: 41 patients were identified. In two cases microscopic infiltration of one margin was found (R1); in one case a close margin was identified. In 26 cases reconstruction was performed using free flaps, and in the remaining cases a pectoralis major flap was used. In three cases postoperative complications were observed. Discussion and conclusions: In theory, lip-splitting and mandible discontinuity could allow for increased access and tumor visualization, and could facilitate flap positioning. Nevertheless, in our experience, it is not necessary in the case of total or subtotal glossectomy.
Simplified Design of Magnetic Gear by Considering the Maximum Transmission Torque Line
Authors: Misron Norhisam , Mohd Saini Luqman , Aris Ishak , Vaithilingam Chockalingam Aravind , Tsuyoshi Hanamoto
Published: November 2020

Magnetic gears (MGs) technology is studied widely among research institutions, with several improvements being documented. This development attracts a high amount of attention due to the demand in the development of magnetic gears towards higher performance than the conventional mechanical counterpart. In general, the design is complicated and there is a lack in detailed references for designing an MG for specific transmission torque as required by its application. Trial-and-error approaches have been the norm in achieving the desired torque by referring the existing MGs for the desired value of torque. This paper presents a new simplified approach towards designing an MG for the required torque and size by referring through a Maximum Transmission Torque Line (MTTL) reference. Finite element method (FEM) is used in analyzing randomly designed magnetic gears with various parameters towards the desired values of the MTTL. The proposed approach of MTTL is a new approach to estimate the total volume of permanent magnets (PMs) required for the MG to achieve the desired transmission torque. The reference line is used to generate equation relating the specific parameters of MG to develop the simplified design of MG based on the estimated total volume of PMs. This simplified way details to 8.5% of error in targeting the desired transmission torque, a means and way for the first stage of the MG design approach to reduce the conventional approaches.
Development of a Surface-Functionalized Titanium Implant for Promoting Osseointegration: Surface Characteristics, Hemocompatibility, and In Vivo Evaluation
Authors: Hou Ping-Jen , Syam Syamsiah , Lan Wen-Chien , Ou Keng-Liang , Huang Bai-Hung , Chan Ka-Chun , Tsai Chi-Hsun , Saito Takashi , Liu Chung-Ming , Chou Hsin-Hua , Huang Yueh-Tzu , Fan Fang-Yu
Published: November 2020

This study aimed to evaluate the impact of surface-modified biomedical titanium (Ti) dental implant on osseointegration. The surfaces were modified using an innovative dip-coating technique (IDCT; sandblasted, large-grit, and acid-etched, then followed by coating with the modified pluronic F127 biodegradable polymer). The surface morphology and hemocompatibility evaluations were investigated by field-emission scanning electron microscopy, while the contact analysis was observed by goniometer. The IDCT-modified Ti implant was also implanted in patients with missing teeth by single-stage surgical procedure then observed immediately and again four months after placement by cone-beam computerized tomography (CBCT) imaging. It was found that the IDCT-modified Ti implant was rougher than the dental implant without surface modification. Contact angle analysis showed the IDCT-modified Ti implant was lower than the dental implant without surface modification. The hemocompatibility evaluations showed greater red blood cell aggregation and fibrin filament formation on the IDCT-modified Ti implant. The radiographic and CBCT image displayed new bone formation at four months after the IDCT-modified Ti implant placement. Therefore, this study suggests that the IDCT-modified Ti dental implant has great potential to accelerate osseointegration.
Visual-Based Localization Using Pictorial Planar Objects in Indoor Environment
Authors: Meng Yu , Lin Kwei-Jay , Tsai Bo-Lung , Chuang Ching-Chi , Cao Yuheng , Zhang Bin
Published: November 2020

Localization is an important technology for smart services like autonomous surveillance, disinfection or delivery robots in future distributed indoor IoT applications. Visual-based localization (VBL) is a promising self-localization approach that identifies a robot’s location in an indoor or underground 3D space by using its camera to scan and match the robot’s surrounding objects and scenes. In this study, we present a pictorial planar surface based 3D object localization framework. We have designed two object detection methods for localization, ArPico and PicPose. ArPico detects and recognizes framed pictures by converting them into binary marker codes for matching with known codes in the library. It then uses the corner points on a picture’s border to identify the camera’s pose in the 3D space. PicPose detects the pictorial planar surface of an object in a camera view and produces the pose output by matching the feature points in the view with that in the original picture and producing the homography to map the object’s actual location in the 3D real world map. We have built an autonomous moving robot that can self-localize itself using its on-board camera and the PicPose technology. The experiment study shows that our localization methods are practical, have very good accuracy, and can be used for real time robot navigation.
Functions of Landscape in Games—A Theoretical Approach with Case Examples
Authors: Kühne Olaf , Jenal Corinna , Edler Dennis
Published: November 2020

The significance of play in the construction of landscape involving the feedback relationships between social conventions and the individual and between the individual and physical space, contrastingly, has so far received only little scientific attention. Games, however, take on great significance in the process of socialization in order to introduce the socializing person into the interpretations, valuations, and practices of the social world, which applies correspondingly to landscape. Play is an essential element of comprehending the concept “landscape”. Accordingly, this present essay deals with conceptual considerations of the function of games in relation to the social and individual construction of landscape. The theoretical framing of landscape will be carried out within the theory of the three landscapes, following Karl Popper’s three worlds. This theoretical framing also involves fundamental considerations on the connection between games and landscapes, which will be illustrated in more detail by means of two case examples, i.e., model railroads and pinball landscapes. It is shown that the playful engagement with landscape takes place in two dimensions: On the one hand, role expectations, norms, and values associated with landscape are conveyed, thus providing guidance for individual construction and individual experience of landscape. On the other hand, landscape contingencies can be tested. They address norms of interpretation and evaluation of landscape that are considered as bound together. Moreover, innovations can be tested, which may have been established in the social understanding of landscape.
Effect of High-Temperature Events When Heading into the Maturity Period on Summer Maize (Zea mays L.) Yield in the Huang-Huai-Hai Region, China
Authors: Wei Shengbao , Liu Jing , Li Tiantian , Wang Xiaoying , Peng Anchun , Chen Changqing
Published: November 2020

The predicted increase in the frequency of extreme climatic events in the future may have a negative effect on cereal production, but our understanding of the historical trends of high-temperature events associated with climate change and their long-term impact on summer maize yield is limited. Based on an analysis of historical climate and summer maize yield data from 1980 to 2016 in the Huang-Huai-Hai (3H) region of China, we calculated two high-temperature event indices, namely, high-temperature hours (HTH) and high-temperature degrees (HTD, the sum of the differences between 35 °C and above), and then investigated the temporal trend of high-temperature events from maize heading to maturity and their impact on the yield of summer maize. Our results indicated that the air temperature showed a significant upward trend when heading into the maturity period of summer maize in the 3H region from 1980–2016 and that the increase was greater in the northern Huang-Huai-Hai (N3H) region than in the southern Huang-Huai-Hai (S3H) region. The intensity of high-temperature events when heading into the maturity period increased considerably from 1980 to 2016 in the 3H region, especially in the S3H region. The HTH and HTD increased by 1.30 h and 0.80 °C per decade in the S3H region, respectively. Moreover, a sensitivity analysis of panel data showed that the increases in HTH and HTD when heading into the maturity period had a consistent negative effect on yield in S3H and N3H regions; this effect was more obvious in the S3H region. In the S3H region, a 1 h increase in HTH was found to be associated with a 0.45–1.13% decrease in yield and a 1 °C increase in HTD could result in a yield loss of 1.34–4.29%. High-temperature events were detrimental to summer maize production, and the severity of this effect was projected to increase in the 3H region. In this study, we used two indices (HTH and HTD) to quantify the impact of high-temperature events on summer maize yield during the critical growth phase (heading to maturity) at a small timescale (hours and days). The results of this study can provide a reference for policymakers to use in the formulation of corresponding climate change adaptation strategies.
Construction of a Nanosensor for Non-Invasive Imaging of Hydrogen Peroxide Levels in Living Cells
Authors: Amreen  , Ali Hayssam M. , Ahmad Mohammad , Salem Mohamed Z. M. , Ahmad Altaf
Published: November 2020

Hydrogen peroxide (H2O2) serves fundamental regulatory functions in metabolism beyond the role as damage signal. During stress conditions, the level of H2O2 increases in the cells and causes oxidative stress, which interferes with normal cell growth in plants and animals. The H2O2 also acts as a central signaling molecule and regulates numerous pathways in living cells. To better understand the generation of H2O2 in environmental responses and its role in cellular signaling, there is a need to study the flux of H2O2 at high spatio–temporal resolution in a real-time fashion. Herein, we developed a genetically encoded Fluorescence Resonance Energy Transfer (FRET)-based nanosensor (FLIP-H2O2) by sandwiching the regulatory domain (RD) of OxyR between two fluorescent moieties, namely ECFP and mVenus. This nanosensor was pH stable, highly selective to H2O2, and showed insensitivity to other oxidants like superoxide anions, nitric oxide, and peroxynitrite. The FLIP-H2O2 demonstrated a broad dynamic range and having a binding affinity (Kd) of 247 µM. Expression of sensor protein in living bacterial, yeast, and mammalian cells showed the localization of the sensor in the cytosol. The flux of H2O2 was measured in these live cells using the FLIP-H2O2 under stress conditions or by externally providing the ligand. Time-dependent FRET-ratio changes were recorded, which correspond to the presence of H2O2. Using this sensor, real-time information of the H2O2 level can be obtained non-invasively. Thus, this nanosensor would help to understand the adverse effect of H2O2 on cell physiology and its role in redox signaling.
Digital PCR: What Relevance to Plant Studies?
Authors: Morcia Caterina , Ghizzoni Roberta , Delogu Chiara , Andreani Lorella , Carnevali Paola , Terzi Valeria
Published: November 2020

Digital PCR (dPCR) is a breakthrough technology that able to provide sensitive and absolute nucleic acid quantification. It is a third-generation technology in the field of nucleic acid amplification. A unique feature of the technique is that of dividing the sample into numerous separate compartments, in each of which an independent amplification reaction takes place. Several instrumental platforms have been developed for this purpose, and different statistical approaches are available for reading the digital output data. The dPCR assays developed so far in the plant science sector were identified in the literature, and the major applications, advantages, disadvantages, and applicative perspectives of the technique are presented and discussed in this review.
Structural Insights into the Heme Pocket and Oligomeric State of Non-Symbiotic Hemoglobins from Arabidopsis thaliana
Authors: Astegno Alessandra , Conter Carolina , Bertoldi Mariarita , Dominici Paola
Published: November 2020

Non-symbiotic hemoglobins AHb1 and AHb2 from Arabidopsis thaliana are hexacoordinate heme-proteins that likely have different biological roles, in view of diverse tissue localization, expression pattern, and ligand binding properties. Herein, we expand upon previous biophysical studies on these isoforms, focusing on their oligomeric states and circular dichroism (CD) characteristics. We found that AHb1 exists in solution in a concentration-dependent monomer-dimer equilibrium, while AHb2 is present only as a monomer. The quaternary structure of AHb1 affects its degree of hexacoordination with the formation of the dimer that enhances pentacoordination. Accordingly, the mutant of a conserved residue within the dimeric interface, AHb1-T45A, which is mostly monomeric in solution, has an equilibrium that is shifted toward a hexacoordinate form compared to the wild-type protein. CD studies further support differences in the globin’s structure and heme moiety. The Soret CD spectra for AHb2 are opposite in sense to those for AHb1, reflecting different patterns of heme-protein side chain contacts in the two proteins. Moreover, the smaller contribution of the heme to the near-UV CD in AHb2 compared to AHb1 suggests a weaker heme-protein association in AHb2. Our data corroborate the structural diversity of AHb1 and AHb2 and confirm the leghemoglobin-like structural properties of AHb2.
High-Density Lipoprotein Modifications: A Pathological Consequence or Cause of Disease Progression?
Authors: Márquez Andrea Bonnin , Nazir Sumra , van der Vorst Emiel P.C.
Published: November 2020

High-density lipoprotein (HDL) is well-known for its cardioprotective effects, as it possesses anti-inflammatory, anti-oxidative, anti-thrombotic, and cytoprotective properties. Traditionally, studies and therapeutic approaches have focused on raising HDL cholesterol levels. Recently, it became evident that, not HDL cholesterol, but HDL composition and functionality, is probably a more fruitful target. In disorders, such as chronic kidney disease or cardiovascular diseases, it has been observed that HDL is modified and becomes dysfunctional. There are different modification that can occur, such as serum amyloid, an enrichment and oxidation, carbamylation, and glycation of key proteins. Additionally, the composition of HDL can be affected by changes to enzymes such as cholesterol ester transfer protein (CETP), lecithin-cholesterol acyltransferase (LCAT), and phospholipid transfer protein (PLTP) or by modification to other important components. This review will highlight some main modifications to HDL and discuss whether these modifications are purely a consequential result of pathology or are actually involved in the pathology itself and have a causal role. Therefore, HDL composition may present a molecular target for the amelioration of certain diseases, but more information is needed to determine to what extent HDL modifications play a causal role in disease development.
Molecular and Cellular Mechanisms of Electronegative Lipoproteins in Cardiovascular Diseases
Authors: Ke Liang-Yin , Law Shi Hui , Mishra Vineet Kumar , Parveen Farzana , Chan Hua-Chen , Lu Ye-Hsu , Chu Chih-Sheng
Published: November 2020

Dysregulation of glucose and lipid metabolism increases plasma levels of lipoproteins and triglycerides, resulting in vascular endothelial damage. Remarkably, the oxidation of lipid and lipoprotein particles generates electronegative lipoproteins that mediate cellular deterioration of atherosclerosis. In this review, we examined the core of atherosclerotic plaque, which is enriched by byproducts of lipid metabolism and lipoproteins, such as oxidized low-density lipoproteins (oxLDL) and electronegative subfraction of LDL (LDL(−)). We also summarized the chemical properties, receptors, and molecular mechanisms of LDL(−). In combination with other well-known markers of inflammation, namely metabolic diseases, we concluded that LDL(−) can be used as a novel prognostic tool for these lipid disorders. In addition, through understanding the underlying pathophysiological molecular routes for endothelial dysfunction and inflammation, we may reassess current therapeutics and might gain a new direction to treat atherosclerotic cardiovascular diseases, mainly targeting LDL(−) clearance.
Reproductive Outcomes and Fertility Preservation Strategies in Women with Malignant Ovarian Germ Cell Tumors after Fertility Sparing Surgery
Authors: Vasta Francesca Maria , Dellino Miriam , Bergamini Alice , Gargano Giulio , Paradiso Angelo , Loizzi Vera , Bocciolone Luca , Silvestris Erica , Petrone Micaela , Cormio Gennaro , Mangili Giorgia
Published: November 2020

Malignant ovarian germ cell tumors are rare tumors that mainly affect patients of reproductive age. The aim of this study was to investigate the reproductive outcomes and fertility preservation strategies in malignant ovarian germ cell tumors after fertility-sparing surgery. Data in literature support that fertility-sparing surgery is associated with an excellent oncological outcome not only in early stages malignant ovarian germ cell tumors but also in advanced stages. Moreover, the possibility of performing conservative treatment should be considered even in case of relapse or advanced disease, given the high chemosensitivity. Indeed, available data have shown that menstrual function is maintained after platinum-based regimens in over 85–95% of patients with malignant ovarian germ cell tumors and rate of premature menopause reported in literature ranges between 3% and 7.4%, while premature ovarian failure rates are between 3.4% and 5%. Moreover, reproductive outcomes are about 80% with no increase in the risk of teratogenicity compared to general population. Therefore, conservative surgery for malignant ovarian germ cell tumors currently may represent a therapeutic option in patients who wish to preserve fertility but must be available for extended follow-up and after subscribing to informed consent.
Levels and Factors Associated with Resilience in Italian Healthcare Professionals during the COVID-19 Pandemic: A Web-Based Survey
Authors: Lisi Lucia , Ciaffi Jacopo , Bruni Antonella , Mancarella Luana , Brusi Veronica , Gramegna Pasquale , Ripamonti Claudio , Quaranta Elisabetta , Borlandelli Elena , Gallo Gaetano , Garofalo Eugenio , Chiaravalloti Agostino , Viola Pasquale , Ruscitti Piero , Caio Giacomo , D’Onghia Martina , D’Amuri Andrea , Cimellaro Antonio , Facchini Giancarlo , La Regina Micaela , Spinardi Luca , De Giorgio Roberto , Giacomelli Roberto , Landini Maria Paola , Berardi Domenico , Meliconi Riccardo , Ursini Francesco
Published: November 2020

Background: Resilience is defined as the capacity to cope successfully with change or adversity. The aims of our study were to investigate levels of resilience in Italian healthcare professionals (HCPs) during the Coronavirus disease 2019 (COVID-19) pandemic and to identify potential predictors of resilience. Methods: We performed a web-based survey of HCPs (n = 1009) working in Italian hospitals during the COVID-19 pandemic. The survey contained a 14-item resilience scale (RS14) and questionnaires to evaluate depression and anxiety symptoms. Non-HCP individuals (n = 375) from the general population were used for comparison. Results: HCPs showed significantly lower resilience compared to the control group (p = 0.001). No significant differences were observed after stratification for geographical area, work setting, role, or suspected/confirmed diagnosis of COVID-19. In a linear regression analysis, RS14 was inversely correlated with depression (R2 = 0.227, p < 0.001) and anxiety (R2 = 0.117, p < 0.001) and directly correlated with age (R2 = 0.012, p < 0.001) but not with body mass index (BMI, R2 = 0.002, p = 0.213). In male HCPs, higher depression score (odds ratio (OR) 1.147, p < 0.001) or BMI (OR 1.136, p = 0.011) significantly predicted having low resilience. In female HCPs, higher depression score (OR 1.111, p < 0.0001) and working in a COVID-19 free setting (OR 2.308, p = 0.002) significantly predicted having low resilience. HCPs satisfied with personal protective equipment had higher levels of resilience (p < 0.010). Conclusions: Our findings suggest that resilience was lower in Italian HCPs than in the general population after the first COVID-19 wave. Specific factors can be identified, and targeted interventions may have an important role to foster resilience of HCPs.
Lean Thinking and Industrial 4.0 Approach to Achieving Construction 4.0 for Industrialization and Technological Development
Authors: Lekan Amusan , Clinton Aigbavboa , Fayomi Ojo Sunday Isaac , James Owolabi
Published: November 2020

The construction industry is responsible for the infrastructural and physical development of nations and plays a pivotal role in determining economic equilibrium of nations of the world; hence, there is a need for constant evolving of advanced ways of carrying out construction operations. The concept has led to the evolution of Construction 4.0, which entails harmonizing disruption in technological applications to enhance construction productivity. The study, therefore, provides an attempt at evolving an enhanced approach to improve construction processes and resource management through application of lean construction and Industry 4.0. The purposive sampling method was used in this study to collect data. The data collection instrument consists of a structured questionnaire designed in a Likert scale of 1 to 5 distributed to 100 construction professionals through an online method that is actively involved in construction operations. The following parameters were censored and profiled, while the results are in tables and charts. The parameters include areas of lean thinking that could enhance Construction 4.0, areas of disruption in Industry 4.0 that influence Construction 4.0 advancement and parameters for practical integrating of lean thinking approach and Industry 4.0. Additionally, the influence of Industry 4.0 in technological development for the construction industry, disruptive innovation of Industry 4.0 and gains towards Construction 4.0. Furthermore, the relevance of Construction 4.0 in construction productivity, the importance of Construction 4.0, industrial application drivers in achieving Construction 4.0, future of Construction 4.0, achieving automation goal in construction and performance expectation of lean thinking and Industry 4.0 in the construction industry are found necessary. Simple percentage, Spearman rankings, Chi-square test, Student-T test, Mann–Whitney-U test and Relative Agreement and Importance index are the tools used to process the data. The study discovered, among others, the veracity of contingency approach in harnessing attributes of the lean thinking concept and disruptive applications in achieving Construction 4.0. The study recommends the application of the hybrid model suggested in the study as a guide to deployment of an application that could help in industrial productivity.
Modifying Adaptive Therapy to Enhance Competitive Suppression
Authors: Hansen Elsa , Read Andrew F.
Published: November 2020

Adaptive therapy is a promising new approach to cancer treatment. It is designed to leverage competition between drug-sensitive and drug-resistant cells in order to suppress resistance and maintain tumor control for longer. Prompted by encouraging results from a recent pilot clinical trial, we evaluate the design of this initial test of adaptive therapy and identify three simple modifications that should improve performance. These modifications are designed to increase competition and are easy to implement. Using the mathematical model that supported the recent adaptive therapy trial, we show that the suggested modifications further delay time to tumor progression and also increase the range of patients who can benefit from adaptive therapy.
Pathogenic Germline Mutations of DNA Repair Pathway Components in Early-Onset Sporadic Colorectal Polyp and Cancer Patients
Authors: Chang Pi-Yueh , Chang Shih-Cheng , Wang Mei-Chia , Chen Jinn-Shiun , Tsai Wen-Sy , You Jeng-Fu , Chen Chia-Chun , Liu Hsiu-Ling , Chiang Jy-Ming
Published: November 2020

Given recent increases in the proportion of early-onset colorectal cancer (CRC), researchers are urgently working to establish a multi-gene screening test for both inherited and sporadic cancer-susceptible individuals. However, the incidence and spectrum of germline mutations in young sporadic CRC patients in East Asian countries and, especially, in sporadic polyp carriers and normal individuals are unknown. Peripheral blood samples were collected from 43 colonoscopy-proved normal controls and from 50 polyp patients and 49 CRC patients with no self-reported family history of cancer. All participants were under 50 years old. Next-generation sequencing with a panel of 30 CRC-associated susceptibility genes was employed to detect pathogenic germline mutations. The germline mutation carrier rates were 2.3%, 4.0%, and 12.2% in the normal, polyp, and cancer groups, respectively. A total of seven different mutations in six DNA repair pathway-related genes (MLH1, BRCA1, BRCA2, CHEK2, BLM, and NTHL1) were detected in nine participants. One frameshift mutation in BRCA2 and one frameshift mutation in the CHEK2 gene were found in a normal control and two colorectal polyp patients, respectively. One young sporadic CRC patient carried two heterozygous mutations, one in MLH1 and one in BRCA1. Three mutations (MLH1 p.Arg265Cys, MLH1 p.Tyr343Ter and CHEK2 p.Ile158TyrfsTer10) were each found in two independent patients and were considered “founder” mutations. This is the first report to demonstrate high percentage of germline mutations in young sporadic colorectal polyp, CRC, and general populations. A multi-gene screening test is warranted for the proactive identification of cancer-predisposed individuals.
Emerging Role of Extracellular Vesicles in Immune Regulation and Cancer Progression
Authors: Mittal Sonam , Gupta Prachi , Chaluvally-Raghavan Pradeep , Pradeep Sunila
Published: November 2020

The development of effective therapies for cancer treatment requires a better understanding of the tumor extracellular environment and a dynamic interaction between tumor cells, the cells of the immune system, and the tumor stroma. Increasing evidence suggests that extracellular vesicles play an important role in this interaction. Extracellular vesicles are nanometer-sized membrane-bound vesicles secreted by various types of cells that facilitate intracellular communication by transferring proteins, various lipids, and nucleic acids, especially miRNAs, between cells. Extracellular vesicles play discrete roles in the immune regulatory functions, such as antigen presentation, and activation or suppression of immune cells. Achieving therapeutic intervention through targeting of extracellular vesicles is a crucial area of research now. Thus, a deeper knowledge of exosome biology and the molecular mechanism of immune regulation is likely to provide significant insight into therapeutic intervention utilizing extracellular vesicles to combat this dreadful disease. This review describes the recent updates on immune regulation by extracellular vesicles in cancer progression and possible use in cancer therapy.
High Surface Area VOx/TiO2/SBA-15 Model Catalysts for Ammonia SCR Prepared by Atomic Layer Deposition
Authors: Shen Jun , Hess Christian
Published: November 2020

The mode of operation of titania-supported vanadia (VOx) catalysts for NOx abatement using ammonia selective catalytic reduction (NH3-SCR) is still vigorously debated. We introduce a new high surface area VOx/TiO2/SBA-15 model catalyst system based on mesoporous silica SBA-15 making use of atomic layer deposition (ALD) for controlled synthesis of titania and vanadia multilayers. The bulk and surface structure is characterized by X-ray diffraction (XRD), UV-vis and Raman spectroscopy, as well as X-ray photoelectron spectroscopy (XPS), revealing the presence of dispersed surface VOx species on amorphous TiO2 domains on SBA-15, forming hybrid Si–O–V and Ti–O–V linkages. Temperature-dependent analysis of the ammonia SCR catalytic activity reveals NOx conversion levels of up to ~60%. In situ and operando diffuse reflection IR Fourier transform (DRIFT) spectroscopy shows N–Hstretching modes, representing adsorbed ammonia and -NH2 and -NH intermediate structures on Bronsted and Lewis acid sites. Partial Lewis acid sites with adjacent redox sites are proposed as the active sites and desorption of product molecules as the rate-determining step at low temperature. The high NOx conversion is attributed to the presence of highly dispersed VOx species and the moderate acidity of VOx supported on TiO2/SBA-15.
Benchmarking Perovskite Electrocatalysts’ OER Activity as Candidate Materials for Industrial Alkaline Water Electrolysis
Authors: Matienzo DJ Donn , Kutlusoy Tuğçe , Divanis Spyridon , Bari Chiara , Instuli Emanuele
Published: November 2020

The selection and evaluation of electrocatalysts as candidate materials for industrial alkaline water electrolysis is fundamental in the development of promising energy storage and sustainable fuels for future energy infrastructure. However, the oxygen evolution reaction (OER) activities of various electrocatalysts already reported in previous studies are not standardized. This work reports on the use of perovskite materials (LaFeO3, LaCoO3, LaNiO3, PrCoO3, Pr0.8Sr0.2CoO3, and Pr0.8Ba0.2CoO3) as OER electrocatalysts for alkaline water electrolysis. A facile co-precipitation technique with subsequent thermal annealing (at 700 °C in air) was performed. Industrial requirements and criteria (cost and ease of scaling up) were well-considered for the selection of the materials. The highest OER activity was observed in LaNiO3 among the La-based perovskites, and in Pr0.8Sr0.2CoO3 among the Pr-based perovskites. Moreover, the formation of double perovskites (Pr0.8Sr0.2CoO3 and Pr0.8Ba0.2CoO3) improved the OER activity of PrCoO3. This work highlights that the simple characterization and electrochemical tests performed are considered the initial step in evaluating candidate catalyst materials to be used for industrial alkaline water electrolysis.
Dehydration of Biomass-Derived Butanediols over Rare Earth Zirconate Catalysts
Authors: Matsuda Asami , Matsumura Yoshitaka , Nakazono Kazuki , Sato Fumiya , Takahashi Ryoji , Yamada Yasuhiro , Sato Satoshi
Published: November 2020

The aim of this work is to develop an effective catalyst for the conversion of butanediols, which is derivable from biomass, to valuable chemicals such as unsaturated alcohols. The dehydration of 1,4-, 1,3-, and 2,3-butanediol to form unsaturated alcohols such as 3-buten-1-ol, 2-buten-1-ol, and 3-buten-2-ol was studied in a vapor-phase flow reactor over sixteen rare earth zirconate catalysts at 325 °C. Rare earth zirconates with high crystallinity and high specific surface area were prepared in a hydrothermal treatment of co-precipitated hydroxide. Zirconates with heavy rare earth metals, especially Y2Zr2O7 with an oxygen-defected fluorite structure, showed high catalytic performance of selective dehydration of 1,4-butanediol to 3-buten-1-ol and also of 1,3-butanediol to form 3-buten-2-ol and 2-buten-1-ol, while the zirconate catalysts were less active in the dehydration of 2,3-butanediol. The calcination of Y2Zr2O7 significantly affected the catalytic activity of the dehydration of 1,4-butanediol: a calcination temperature of Y2Zr2O7 at 900 °C or higher was efficient for selective formation of unsaturated alcohols. Y2Zr2O7 with high crystallinity exhibits the highest productivity of 3-buten-1-ol from 1,4-butanediol at 325 °C.
Flow-Through Macroporous Polymer Monoliths Containing Artificial Catalytic Centers Mimicking Chymotrypsin Active Site
Authors: Stepanova Mariia , Solomakha Olga , Ten Daria , Tennikova Tatiana , Korzhikova-Vlakh Evgenia
Published: November 2020

Synthetic catalysts that could compete with enzymes in term of the catalytic efficiency but surpass them in stability have a great potential for the practical application. In this work, we have developed a novel kind of organic catalysts based on flow-through macroporous polymer monoliths containing catalytic centers that mimic the catalytic site of natural enzyme chymotrypsin. It is known that chymotrypsin catalytic center consists of L-serine, L-histidine, and L-aspartic acid and has specificity to C-terminal residues of hydrophobic amino acids (L-phenylalanine, L-tyrosine, and L-tryptophan). In this paper, we have prepared the macroporous polymer monoliths bearing grafted polymer layer on their surface. The last one was synthesized via copolymerization of N-methacryloyl-L-serine, N-methacryloyl-L-histidine, and N-methacryloyl-L-aspartic acid. The spatial orientation of amino acids in the polymer layer, generated on the surface of monolithic framework, was achieved by coordinating amino acid-polymerizable derivatives with cobalt (II) ions without substrate-mimicking template and with its use. The conditions for the preparation of mimic materials were optimized to achieve a mechanically stable system. Catalytic properties of the developed systems were evaluated towards the hydrolysis of ester bond in a low molecular substrate and compared to the results of using chymotrypsin immobilized on the surface of a similar monolithic framework. The effect of flow rate increase and temperature elevation on the hydrolysis efficiency were evaluated for both mimic monolith and column with immobilized enzyme.
Biodiesel: Modified Mixed Oxides as Catalyst for Transesterification of Rapeseed Oil
Authors: Aleš Vávra , Zdeněk Tišler , Jaroslav Kocík , Jakub Smutek
Published: November 2020

Biodiesel, as one of the alternative biofuels replacing the common fossil fuels, is prepared by transesterification of oils and fats. Commonly, the reaction is catalysed by either acidic or basic catalysts. The availability of the active sites to large triglyceride molecules is the key factor of the heterogeneous catalysts. The use of carbon fibres during the synthesis of Mg/Fe layered double hydroxides results in the formation of macropores during the calcination. The amount of carbon fibres showed an important effect on the textural properties of the resulting mixed oxides. The texture was determined by N2-adsorption and Hg-porosity. The catalyst activity in the studied reaction was examined by determination of ester amount by gas chromatography and the activity was compared with unmodified mixed oxides. The highest ester yield (40 wt.%) was achieved by adding 1 wt.% of carbon fibres to the catalyst with the largest size of macropores.
Assessment of the Nutritional Status, Diet and Intestinal Parasites in Hosted Saharawi Children
Authors: Gozalbo Mónica , Guillen Marisa , Taroncher-Ferrer Silvia , Cifre Susana , Carmena David , Soriano José M , Trelis María
Published: November 2020

Since the early 1990s, Spanish humanitarian associations have welcomed Saharawi children from the refugee camps in Tindouf (Argelia). These children are the most affected by the lack of food, water, hygienic measures and health care. The main objective of this study was to analyze the anthropometric, nutritional and parasitological data of 38 Saharawi boys and girls (from 10 to 13 years old) under a holiday host program in the city of Valencia. Our results confirm that malnutrition and multiparasitism are highly frequent, so it is understood that living conditions in refugee camps continue to be precarious with a lack of proper hygiene and nutrition. Furthermore, biochemical alterations, lactose malabsorption and the risk of celiac disease, also detected in our study as a secondary objective, will complicate nutritional management and restoration of health. For this reason, sustainable feeding alternatives and interventions from a hygienic and nutritional point of view are proposed, emphasizing in an improvement in the education of parents and children.
Syntheses and Step-by-Step Morphological Analysis of Nano-Copper-Decorated Carbon Long Fibers for Aerospace Structural Applications
Authors: Daoush Walid M. , Albogmy Turki S. , Khamis Moath A. , Inam Fawad
Published: November 2020

Carbon long fiber/copper composites were prepared using electroless and electroplating methods with copper metal for potential aerospace applications. Carbon fibers were heat-treated at 450 °C followed by acid treatment before the metallization processes. Three different methods of metallization processes were applied: electroless silver deposition, electroless copper deposition and electroplating copper deposition. The metallized carbon fibers were subjected to copper deposition via two different routes. The first method was the electroless deposition technique in an alkaline tartrate bath using formaldehyde as a reducing agent of the copper ions from the copper sulphate solution. The second method was conducted by copper electroplating on the chemically treated carbon fibers. The produced carbon fiber/copper composites were extensively investigated by Field-Emission Scanning Electron Microscopy (FE-SEM) supported with an Energy Dispersive X-Ray Analysis (EDAX) unit to analyze the size, surface morphology, and chemical composition of the produced carbon long fiber/copper composites. The results show that the carbon fiber/copper composites prepared using the electroplating method had a coated type surface morphology with good adhesion between the copper coated layer and the surface of the carbon fibers. However, the carbon fiber/copper composites prepared using the electroless deposition had a decorated type morphology. Moreover, it was observed that the metallized carbon fibers using the silver method enhanced the electroless copper coating process with respect to the electroless copper coating process without silver metallization. The electrical conductivity of the carbon fiber/copper composites was improved by metallization of the carbon fibers using silver, as well as by the electrodeposition method.
Experimental and Modeling Study on the High-Performance p++-GaAs/n++-GaAs Tunnel Junctions with Silicon and Tellurium Co-Doped InGaAs Quantum Well Inserted
Authors: Gou Yudan , Wang Jun , Cheng Yang , Guo Yintao , Xiao Xiao , Liu Heng , Tan Shaoyang , Zhou Li , Yang Huomu , Deng Guoliang , Zhou Shouhuan
Published: November 2020

The development of high-performance tunnel junctions is critical for achieving high efficiency in multi-junction solar cells (MJSC) that can operate at high concentrations. We investigate silicon and tellurium co-doping of InGaAs quantum well inserts in p++-GaAs/n++-GaAs tunnel junctions and report a peak current density as high as 5839 A cm−2 with a series resistance of 5.86 × 10−5 Ω cm2. In addition, we discuss how device performance is affected by the growth temperature, thickness, and V/III ratio in the InGaAs layer. A simulation model indicates that the contribution of trap-assisted tunneling enhances carrier tunneling.
Molecular Packing Interaction in DNA Crystals
Authors: Shamim Amen , Parveen Nazia , Subramani Vinod Kumar , Kim Kyeong Kyu
Published: November 2020

DNA crystallography provides essential structural information to understand the biochemical and biological functions of oligonucleotides. Therefore, it is necessary to understand the factors affecting crystallization of DNA to develop a strategy for production of diffraction-quality DNA crystals. We analyzed key factors affecting intermolecular interactions in 509 DNA crystals from the Nucleic Acid Database and Protein Databank. Packing interactions in DNA crystals were classified into four categories based on the intermolecular hydrogen bonds in base or backbone, and their correlations with other factors were analyzed. From this analysis, we confirmed that hydrogen bonding between terminal end and mid-region is most common in crystal packing and in high-resolution crystal structures. Interestingly, P212121 is highly preferred in DNA crystals in general, but the P61 space group is relatively abundant in A-DNA crystals. Accordingly, P212121 contains more terminal end-mid-region interactions than other space groups, confirming the significance of this interaction. While metals play a role in the production of a good crystal in B-DNA conformation, their effect is not significant in other conformations. From these analyses, we found that packing interaction and other factors have a strong influence on the quality of DNA crystals and provide key information to predict crystal growth of candidate oligonucleotides.
UVB LEDs Grown by Molecular Beam Epitaxy Using AlGaN Quantum Dots
Authors: Brault Julien , Khalfioui Mohamed Al , Matta Samuel , Ngo Thi Huong , Chenot Sébastien , Leroux Mathieu , Valvin Pierre , Gil Bernard
Published: November 2020

AlGaN based light emitting diodes (LEDs) will play a key role for the development of applications in the ultra-violet (UV). In the UVB region (280–320 nm), phototherapy and plant lighting are among the targeted uses. However, UVB LED performances still need to be improved to reach commercial markets. In particular, the design and the fabrication process of the active region are central elements that affect the LED internal quantum efficiency (IQE). We propose the use of nanometer-sized epitaxial islands (i.e., so called quantum dots (QDs)) to enhance the carrier localization and improve the IQE of molecular beam epitaxy (MBE) grown UVB LEDs using sapphire substrates with thin sub-µm AlN templates. Taking advantage of the epitaxial stress, AlGaN QDs with nanometer-sized (≤10 nm) lateral and vertical dimensions have been grown by MBE. The IQE of the QDs has been deduced from temperature dependent and time resolved photoluminescence measurements. Room temperature IQE values around 5 to 10% have been found in the 290–320 nm range. QD-based UVB LEDs were then fabricated and characterized by electrical and electroluminescence measurements. On-wafer measurements showed optical powers up to 0.25 mW with external quantum efficiency (EQE) values around 0.1% in the 305–320 nm range.
The Use of the Central Vein Sign in the Diagnosis of Multiple Sclerosis: A Systematic Review and Meta-analysis
Authors: Castellaro Marco , Tamanti Agnese , Pisani Anna Isabella , Pizzini Francesca Benedetta , Crescenzo Francesco , Calabrese Massimiliano
Published: November 2020

Background: The central vein sign (CVS) is a radiological feature proposed as a multiple sclerosis (MS) imaging biomarker able to accurately differentiate MS from other white matter diseases of the central nervous system. In this work, we evaluated the pooled proportion of the CVS in brain MS lesions and to estimate the diagnostic performance of CVS to perform a diagnosis of MS and propose an optimal cut-off value. Methods: A systematic search was performed on publicly available databases (PUBMED/MEDLINE and Web of Science) up to 24 August 2020. Analysis of the proportion of white matter MS lesions with a central vein was performed using bivariate random-effect models. A meta-regression analysis was performed and the impact of using particular sequences (such as 3D echo-planar imaging) and post-processing techniques (such as FLAIR*) was investigated. Pooled sensibility and specificity were estimated using bivariate models and meta-regression was performed to address heterogeneity. Inclusion and publication bias were assessed using asymmetry tests and a funnel plot. A hierarchical summary receiver operating curve (HSROC) was used to estimate the summary accuracy in diagnostic performance. The Youden index was employed to estimate the optimal cut-off value using individual patient data. Results: The pooled proportion of lesions showing a CVS in the MS population was 73%. The use of the CVS showed a remarkable diagnostic performance in MS cases, providing a pooled specificity of 92% and a sensitivity of 95%. The optimal cut-off value obtained from the individual patient data pooled together was 40% with excellent accuracy calculated by the area under the ROC (0.946). The 3D-EPI sequences showed both a higher pooled proportion compared to other sequences and explained heterogeneity in the meta-regression analysis of diagnostic performances. The 1.5 Tesla (T) scanners showed a lower (58%) proportion of MS lesions with a CVS compared to both 3T (74%) and 7T (82%). Conclusions: The meta-analysis we have performed shows that the use of the CVS in differentiating MS from other mimicking diseases is encouraged; moreover, the use of dedicated sequences such as 3D-EPI and the high MRI field is beneficial.