bluuebunny/crossref_metadata_2025 huggingface dataset:
Microglial Depletion Has No Impact on Disease Progression in a Mouse Model of Machado–Joseph Disease
Authors: Campos Ana Bela , Duarte-Silva Sara , Fernandes Bruno , Coimbra Bárbara , Campos Jonas , Monteiro-Fernandes Daniela , Teixeira-Castro Andreia , Ambrósio António Francisco , Maciel Patrícia
Published: June 2022

Machado–Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3), is an autosomal dominant neurodegenerative disorder (ND). While most research in NDs has been following a neuron-centric point of view, microglia are now recognized as crucial in the brain. Previous work revealed alterations that point to an increased activation state of microglia in the brain of CMVMJD135 mice, a MJD mouse model that replicates the motor symptoms and neuropathology of the human condition. Here, we investigated the extent to which microglia are actively contributing to MJD pathogenesis and symptom progression. For this, we used PLX3397 to reduce the number of microglia in the brain of CMVMJD135 mice. In addition, a set of statistical and machine learning models were further implemented to analyze the impact of PLX3397 on the morphology of the surviving microglia. Then, a battery of behavioral tests was used to evaluate the impact of microglial depletion on the motor phenotype of CMVMJD135 mice. Although PLX3397 treatment substantially reduced microglia density in the affected brain regions, it did not affect the motor deficits seen in CMVMJD135 mice. In addition to reducing the number of microglia, the treatment with PLX3397 induced morphological changes suggestive of activation in the surviving microglia, the microglia of wild-type animals becoming similar to those of CMVMJD135 animals. These results suggest that microglial cells are not key contributors for MJD progression. Furthermore, the impact of PLX3397 on microglial activation should be taken into account in the interpretation of findings of ND modification seen upon treatment with this CSF1R inhibitor.
GLP-1 Receptor Agonists in Neurodegeneration: Neurovascular Unit in the Spotlight
Authors: Monti Giulia , Gomes Moreira Diana , Richner Mette , Mutsaers Henricus Antonius Maria , Ferreira Nelson , Jan Asad
Published: June 2022

Defects in brain energy metabolism and proteopathic stress are implicated in age-related degenerative neuronopathies, exemplified by Alzheimer’s disease (AD) and Parkinson’s disease (PD). As the currently available drug regimens largely aim to mitigate cognitive decline and/or motor symptoms, there is a dire need for mechanism-based therapies that can be used to improve neuronal function and potentially slow down the underlying disease processes. In this context, a new class of pharmacological agents that achieve improved glycaemic control via the glucagon-like peptide 1 (GLP-1) receptor has attracted significant attention as putative neuroprotective agents. The experimental evidence supporting their potential therapeutic value, mainly derived from cellular and animal models of AD and PD, has been discussed in several research reports and review opinions recently. In this review article, we discuss the pathological relevance of derangements in the neurovascular unit and the significance of neuron–glia metabolic coupling in AD and PD. With this context, we also discuss some unresolved questions with regard to the potential benefits of GLP-1 agonists on the neurovascular unit (NVU), and provide examples of novel experimental paradigms that could be useful in improving our understanding regarding the neuroprotective mode of action associated with these agents.
Maternal Vitamin D Deficiency in Mice Increases White Adipose Tissue Inflammation in Offspring
Authors: Haroun Nicole , Bennour Imene , Seipelt Eva , Astier Julien , Couturier Charlene , Mounien Lourdes , Landrier Jean-François
Published: June 2022

Vitamin D is acknowledged to play an important biological and metabolic role in adipose tissue, which is also the main storage site for this vitamin. Its anti-inflammatory effect in adipocytes and adipose tissue has notably been highlighted in adult mice. This vitamin is also crucial during fetal development since maternal vitamin D deficiency is suspected to program future metabolic disorders. Based on these observations, the aim of this study was to evaluate the consequences of maternal vitamin D deficiency (VDD) on white adipose tissue inflammation in adult offspring fed with normal or obesogenic diet (high-fat diet). White adipose tissue morphology, RNA and miRNA expression profiles, and signaling pathways were studied in adult males and females. In males, a HF diet coupled with maternal VDD increased expression of RNA and miRNA linked to inflammation leading to over-representation of inflammatory pathways. Interestingly, genomic and epigenetic profiles were associated with activation of the NF-kB signaling pathway and adiposity index. In females, no major modulation of inflammatory pathways was observed under VDD, contrarily to males. We concluded that maternal VDD coupled with HF diet activated inflammatory pathway in adipose tissue of the offspring, in a sex-dependent manner. Such activation is strongly related to activation of NF-kB signaling and increased adiposity only in males.
Integrin Regulators in Neutrophils
Authors: Pulikkot Sunitha , Hu Liang , Chen Yunfeng , Sun Hao , Fan Zhichao
Published: June 2022

Neutrophils are the most abundant leukocytes in humans and are critical for innate immunity and inflammation. Integrins are critical for neutrophil functions, especially for their recruitment to sites of inflammation or infections. Integrin conformational changes during activation have been heavily investigated but are still not fully understood. Many regulators, such as talin, Rap1-interacting adaptor molecule (RIAM), Rap1, and kindlin, are critical for integrin activation and might be potential targets for integrin-regulating drugs in treating inflammatory diseases. In this review, we outline integrin activation regulators in neutrophils with a focus on the above critical regulators, as well as newly discovered modulators that are involved in integrin activation.
Mechanotransduction in Skin Inflammation
Authors: Shutova Maria S. , Boehncke Wolf-Henning
Published: June 2022

In the process of mechanotransduction, the cells in the body perceive and interpret mechanical stimuli to maintain tissue homeostasis and respond to the environmental changes. Increasing evidence points towards dysregulated mechanotransduction as a pathologically relevant factor in human diseases, including inflammatory conditions. Skin is the organ that constantly undergoes considerable mechanical stresses, and the ability of mechanical factors to provoke inflammatory processes in the skin has long been known, with the Koebner phenomenon being an example. However, the molecular mechanisms and key factors linking mechanotransduction and cutaneous inflammation remain understudied. In this review, we outline the key players in the tissue’s mechanical homeostasis, the available data, and the gaps in our current understanding of their aberrant regulation in chronic cutaneous inflammation. We mainly focus on psoriasis as one of the most studied skin inflammatory diseases; we also discuss mechanotransduction in the context of skin fibrosis as a result of chronic inflammation. Even though the role of mechanotransduction in inflammation of the simple epithelia of internal organs is being actively studied, we conclude that the mechanoregulation in the stratified epidermis of the skin requires more attention in future translational research.
The Role of the Immune System in the Development of Endometriosis
Authors: Abramiuk Monika , Grywalska Ewelina , Małkowska Paulina , Sierawska Olga , Hrynkiewicz Rafał , Niedźwiedzka-Rystwej Paulina
Published: June 2022

Endometriosis is a chronic disease that affects about 10% of women of reproductive age. It can contribute to pelvic pain, infertility or other conditions such as asthma, cardiovascular disease, breast or ovarian cancer. Research has shown that one of the conditions for the development of endometrial lesions is the dysfunction of the immune system. It appears that immune cells, such as neutrophils, macrophages, NK cells and dendritic cells, may play a specific role in the angiogenesis, growth and invasion of endometriosis cells. Immune cells secrete cytokines and defensins that also affect the endometriosis environment. This review discusses the various components of the immune system that are involved in the formation of endometrial lesions in women.
Computations of a Bluff-Body Stabilised Premixed Flames Using ERN Method
Authors: Amzin Shokri
Published: June 2022

Combustible carbon-based energy is still prevailing as the world’s leading energy due to its high energy density. However, the oxidation of these hydrocarbons disturbs the natural carbon cycle greatly by increasing greenhouse gases. As emission legislation becomes more rigorous, lean premixed combustion becomes promising because it can reduce nitrogen oxides (NOx) and Carbon Monoxide (CO) emissions without compromising efficiency. However, utilising lean premixed flames in industrial combustors is not easy because of its thermo-acoustic instabilities associated with pressure fluctuations and the non-linearity in the mean reaction rate. Therefore, reliable predictive combustion models are required to predict emissions with sensible computational costs to use the mode efficiently in designing environmentally friendly combustion systems. Along with the promising methodologies capable of modelling turbulent premixed flames with low computational costs is the ERN-RANS framework. Thus, this study aims to compute a bluff-body stabilised premixed flames close to blow-Off using the ERN-RANS framework. As a result, a satisfactory agreement is reached between the predicted and measured values.
Machine Learning-Based Radon Monitoring System
Authors: Valcarce Diego , Alvarellos Alberto , Rabuñal Juan Ramón , Dorado Julián , Gestal Marcos
Published: June 2022

Radon (Rn) is a biological threat to cells due to its radioactivity. It is capable of penetrating the human body and damaging cellular DNA, causing mutations and interfering with cellular dynamics. Human exposure to high concentrations of Rn should, therefore, be minimized. The concentration of radon in a room depends on numerous factors, such as room temperature, humidity level, existence of air currents, natural grounds of the buildings, building structure, etc. It is not always possible to change these factors. In this paper we propose a corrective measure for reducing indoor radon concentrations by introducing clean air into the room through forced ventilation. This cannot be maintained continuously because it generates excessive noise (and costs). Therefore, a system for predicting radon concentrations based on Machine Learning has been developed. Its output activates the fan control system when certain thresholds are reached.
Broadband Dielectric Spectroscopic Detection of Ethanol: A Side-by-Side Comparison of ZnO and HKUST-1 MOFs as Sensing Media
Authors: Amoah Papa K. , Hassan Zeinab Mohammed , Lin Pengtao , Redel Engelbert , Baumgart Helmut , Obeng Yaw S.
Published: June 2022

The most common gas sensors are based on chemically induced changes in electrical resistivity and necessarily involve making imperfect electrical contacts to the sensing materials, which introduce errors into the measurements. We leverage thermal- and chemical-induced changes in microwave propagation characteristics (i.e., S-parameters) to compare ZnO and surface-anchored metal–organic-framework (HKUST-1 MOF) thin films as sensing materials for detecting ethanol vapor, a typical volatile organic compound (VOC), at low temperatures. We show that the microwave propagation technique can detect ethanol at relatively low temperatures (<100 °C), and afford new mechanistic insights that are inaccessible with the traditional dc-resistance-based measurements. In addition, the metrological technique avoids the inimical measurand distortions due to parasitic electrical effects inherent in the conductometric volatile organic compound detection.
Recent Trends in the Development of Carbon-Based Electrodes Modified with Molecularly Imprinted Polymers for Antibiotic Electroanalysis
Authors: Preda Daniel , David Iulia Gabriela , Popa Dana-Elena , Buleandra Mihaela , Radu Gabriel Lucian
Published: June 2022

Antibiotics are antibacterial agents applied in human and veterinary medicine. They are also employed to stimulate the growth of food-producing animals. Despite their benefits, the uncontrolled use of antibiotics results in serious problems, and therefore their concentration levels in different foods as well as in environmental samples were regulated. As a consequence, there is an increasing demand for the development of sensitive and selective analytical tools for antibiotic reliable and rapid detection. These requirements are accomplished by the combination of simple, cost-effective and affordable electroanalytical methods with molecularly imprinted polymers (MIPs) with high recognition specificity, based on their “lock and key” working principle, used to modify the electrode surface, which is the “heart” of any electrochemical device. This review presents a comprehensive overview of MIP-modified carbon-based electrodes developed in recent years for antibiotic detection. The MIP preparation and electrode modification procedures, along with the performance characteristics of sensors and analytical methods, as well as the applications for the antibiotics’ quantification from different matrices (pharmaceutical, biological, food and environmental samples), are discussed. The information provided by this review can inspire researchers to go deeper into the field of MIP-modified sensors and to develop efficient means for reliable antibiotic determination.
Loaded Functional Strength Training versus Traditional Physical Therapy on Hip and Knee Extensors Strength and Function Walking Capacity in Children with Hemiplegic Cerebral Palsy: Randomized Comparative Study
Authors: Abd-Elfattah Hanaa Mohsen , Ameen Fairouz Hatem , Elkalla Reham Alaa , Aly Sobhy M. , Abd-Elrahman Noha Ahmed Fouad
Published: June 2022

Objective: This study’s objective was to see how loaded functional strengthening exercises using a plantigrade foot position and a shoe supporter affected muscle strength and walking ability in spastic hemiplegic children. Methods: Seventy-two children with spastic hemiplegic cerebral palsy, both sexes, aged ten to twelve years, were randomly assigned into two groups equal in number (control and intervention groups). The control group received a specially designed physical therapy program, whereas the intervention group received a loaded functional strengthening exercises program using a shoe supporter to maintain a plantigrade foot position. The training program was carried out for 60 min, three times per week for three consecutive months. All participants were evaluated both before and after the therapy program by using a Medical Commander Echo Manual Muscle Tester dynamometer to assess isometric muscle power of hip and knee extensors on the affected side. To assess functional walking capacity, a 6 min walking (6MWT) test was used. Results: Study groups were comparable with respect to all outcome measures at entry (p > 0.05). Within-group comparison showed significant improvements in all measured variables. Furthermore, between-group comparison revealed significantly greater improvements (p < 0.05) in hip and knee extensors strength as well as the functional walking capacity in favor of the intervention group. Conclusions: In all the analyzed variables, loaded functional strength exercises from the plantigrade foot position were found to be considerably more effective in the intervention group than in the control group.
Diagnosis and Treatment of Children with a Radiological Fat Pad Sign without Visible Elbow Fracture Vary Widely: An International Online Survey and Development of an Objective Definition
Authors: Poppelaars Maximiliaan A. , Eygendaal Denise , The Bertram , van Oost Iris , van Bergen Christiaan J. A.
Published: June 2022

Children often present at the emergency department with a suspected elbow fracture. Sometimes, the only radiological finding is a ‘fat pad sign’ (FPS) as a result of hydrops or haemarthros. This sign could either be the result of a fracture, or be due to an intra-articular haematoma without a concomitant fracture. There are no uniform treatment guidelines for this common population. The aims of this study were (1) to obtain insight into FPS definition, diagnosis, and treatment amongst international colleagues, and (2) to identify a uniform definition based on radiographic measurements with optimal cut-off points via a receiver operating characteristic (ROC) curve. An online international survey was set up to assess the diagnostic and treatment strategies, criteria, and definitions of the FPS, the probability of an occult fracture, and the presence of an anterior and/or posterior FPS on 20 radiographs. Additionally, the research team performed radiographic measurements to identify cut-off values for a positive FPS, as well as test–retest reliability and inter-rater reliability via intraclass correlation coefficients (ICC). A total of 133 (paediatric) orthopaedic surgeons completed the survey. Definitions, further diagnostics, and treatments varied considerably amongst respondents. Angle measurements of the fat pad as related to the humeral axis line showed the highest reliability (test–retest ICC, 0.95 (95% CI 0.88–0.98); inter-rater ICC, 0.95 (95% CI 0.91–0.98)). A cut-off angle of 16° was defined a positive anterior FPS (sensitivity, 1.00; specificity, 0.87; accuracy, 99%), based on the respondents’ assessment of the radiographs in combination with the research team’s measurements. Any visible posterior fat pad was defined as a positive posterior FPS. This study provides insight into the current diagnosis and treatment of children with a radiological fat pad sign of the elbow. A clear, objective definition of a positive anterior FPS was identified as a ≥16° angle with respect to the anterior humeral line.
Utilizing Polypropylene Fiber in Sustainable Structural Concrete Mixtures
Authors: Hedjazi Saman , Castillo Daniel
Published: June 2022

Polypropylene fiber reinforced concrete (PFRC) is becoming more popular for structural purposes due to its durability, electrical resistivity, and mechanical properties. In this study, the influence of polypropylene fiber on the mechanical properties and ultrasonic pulse velocity (UPV) of fiber reinforced concrete (FRC) were determined. Six different fiber volume fractions of polypropylene were considered in the experimental investigation with varying water–cement ratios and curing conditions. Non-destructive testing methods were utilized to determine the UPV of the PFRC. Available equations in literature for predicting the RFC’s compressive strength based on UPV values were selected. However, the computed values did not show good agreement with the compressive strengths obtained from the compression testing machine. It was confirmed that polypropylene fibers alter the propagation of UPV, and as a result, the existing equations do not accurately predict the compressive strength for PFRC. Therefore, a practical equation is proposed to accurately evaluate the compressive strength of PFRC with regard to UPV.
Green-High-Performance PMMA–Silica–Li Barrier Coatings
Authors: Trentin Andressa , Chagas Victória Hellen , Uvida Mayara Carla , Pulcinelli Sandra Helena , Santilli Celso Valentim , Hammer Peter
Published: June 2022

Organic-inorganic coatings based on polymethyl methacrylate (PMMA)–silica–lithium are an efficient alternative to protect metals against corrosion. Although the preparation methodology is established and the thin coatings (~10 µm) are highly protective, the use of an environmentally friendly solvent has not yet been addressed. In this work, PMMA–silica coatings were synthesized using 2-propanol as a solvent and deposited on aluminum alloy AA7075, widely used in the aeronautical industry. Different concentrations of lithium carbonate (0–4000 ppm) were incorporated into the hybrid matrix to study the structural and inhibitive effects of Li+ in terms of barrier efficiency of the coatings in contact with saline solution (3.5% NaCl). Structural and morphological characterization by low-angle X-ray scattering, X-ray photoelectron spectroscopy, atomic force microscopy, thermogravimetric analysis, thickness, and adhesion measurements, showed for intermediate lithium content (500–2000 ppm) the formation of a highly polymerized PMMA phase covalently cross-linked by silica nodes, which provide strong adhesion to the aluminum substrate (15 MPa). Electrochemical impedance spectroscopy (EIS) results revealed an excellent barrier property in the GΩ cm2 range and durability of more than two years in a 3.5% NaCl solution. This performance can be attributed to the formation of a highly reticulated phase in the presence of Li, which hinders the permeation of water and ions. Additionally, the self-healing ability of scratched samples was evidenced by EIS assays showing a fast Li-induced formation of insoluble products in damaged areas; thus, constituting an excellent eco-friendly solution for corrosion protection of aerospace components.
Point-of-Care Testing Blood Coagulation Detectors Using a Bio-Microfluidic Device Accompanied by Raman Spectroscopy
Authors: Huang Song-Jeng , Chiang Chao-Ching , Immanuel Philip Nathaniel , Subramania Murugan
Published: June 2022

An efficient technique was developed for the detection of human blood coagulation using a bio-microfluidic device based on Raman spectra [...]
On the Impact of Surface Morphology and Transfer Film on Brake System Performance of High-Capacity Metro Train
Authors: Yang Chi , Yan Haicheng , Chen Qilin , Liu Yongke , Zhang Neng
Published: June 2022

The brake system of Melbourne’s High-Capacity Metro Train (HCMT) suffers from consistently extended braking distances after repeating a set of high-speed tests and the commission process. The degradation of brake system performance affects the safety of rolling stock and its conformance to the design standard. In this paper, the root cause leading to the degraded brake performance was analyzed. The brake discs and brake pads of the affected train and another train with normal working conditions were removed and a series of examinations was to determine the reason for the change of friction coefficient between friction surfaces. The results revealed that brake disc samples from the affected TS02 trainset suffered from changed transfer film and surface morphology after multiple consecutive high-speed braking applications. The factors that may affect the brake system performance were analyzed in the laboratory. It was found the brake disc surface had a lower hardness level, coefficient of friction, and smaller contacting area with the brake pad when compared to the brake disc and pad samples from another trainset. These factors harmed the performance of the braking system, and the decrease in the braking effort led to a longer braking distance than expected and failed braking tests.
Improving the Processability of a One-Step Hydrophobic Coating for Hot-Dipped Galvanised Steel for Industrial Applications
Authors: Williams Jamie , Griffiths Christian , Dunlop Tom , Jewell Eifion
Published: June 2022

Hydrophobicity on steel-based metallic surfaces provides an advantage in limiting corrosion and debris buildup on the surface, thereby, improving the substrate performance. An experimental investigation was conducted on the development of zinc stearate and silicon dioxide coatings on the surface of hot-dipped galvanised zinc-coated steel substrates, which could be used to induce superhydrophobicity. Under optimal formulation and processing conditions, a contact angle of 146° could be produced within a 120-min processing window. This represents a reduction in processing time of 67% over previous literature using similar chemistry. In addition, we proved that costly nano silicon dioxide can be replaced by lower cost micro silicon dioxide without decreasing the performance of the coating contact angle. Under standard accelerated exposure tests, the coating was shown to reduce oxide build up by a factor of 3 compared to uncoated galvanized steel.
Spray Freezing Coating on the Carrier Particles for Powder Preparation
Authors: Xu Qing , Wang Ruixin , Zhang Fan , Wang Ruifang , Wu Long , Lin Bo
Published: June 2022

Carrier particle spray freeze-drying is a new technology with high added value for thermosensitive powder spray freeze-drying. The technology includes the following steps: atomization, coating, freezing, and drying. Due to the action of carrier particles, the condensation of frozen droplets in the conventional spray freeze-drying process is overcome. However, there are many influencing factors involved in the process of freezing coating. The mechanism of the complex droplet collision freezing process still needs to be studied. In this paper, from the perspective of spray freezing coating after atomized droplets collide with low-temperature carrier particles, the coating process and freezing process of single droplets impacting the sphere are analyzed microscopically. The freezing coating processes of static and dynamic carrier particles are reviewed. Moreover, the surface evaluation of powder and equipment development for creating powder products is discussed.
UV Blocking and Oxygen Barrier Coatings Based on Polyvinyl Alcohol and Zinc Oxide Nanoparticles for Packaging Applications
Authors: Channa Iftikhar Ahmed , Ashfaq Jaweria , Gilani Sadaf Jamal , Shah Aqeel Ahmed , Chandio Ali Dad , Jumah May Nasser bin
Published: June 2022

Photodegradation and oxidation are major causes of the deterioration of food, resulting in darkening, off-flavors, and nutrient deficiency. To reduce this problem, novel functional polymeric materials are being developed to retain food’s light sensitivity. Nanofillers are also used in a polymeric film to produce effective UV blockings and oxygen barrier coatings so that the degradation of the food can be delayed, thereby increasing the shelf life. For this purpose, polyvinyl alcohol coatings were prepared by the incorporation of ZnO nanoparticles. Polyvinyl alcohol is a naturally excellent barrier against oxygen, and the addition of ZnO particles at the nanoscale size has demonstrated effective UV blocking capabilities. In this work, the hydrothermal technique is used to produce ZnO nanoparticles, and these produced particles are then incorporated into the polyvinyl alcohol to produce thin films. These films are characterized in terms of the compositional, macroscopic, microscopic, and optical properties via X-ray diffraction (XRD), FTIR, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), as well as UV–VIS spectroscopy. ZnO nanoparticles at different concentrations were incorporated into the PVA solution, and the films were processed via the blade coating method. With the addition of ZnO, the oxygen transmission rate (OTR) of pure PVA was not altered and remained stable, and the lowest OTR was recorded as 0.65 cm3/m2·day·bar. Furthermore, the addition of ZnO increased the water contact angle (WCA) of PVA, and the highest WCA was recorded to be around more than 70°. Due to this, water permeability decreased. Additionally, PVA/ZnO films were highly flexible and bendable and maintained the OTR even after going through bending cycles of 20K. Furthermore, the addition of ZnO showed a significant UV blocking effect and blocked the rays below a wavelength of 380 nm. Finally, the optimized films were used for packaging applications, and it was observed that the packaged apple remained fresh and unoxidized for a longer period as compared with the piece of apple without packaging. Thus, based on these results, the PVA/ZnO films are ideally suited for packaging purposes and can effectively enhance the shelf life of food.
A Study on the Influence of End-Sheath Aging and Moisture Absorption on Abnormal Heating of Composite Insulators
Authors: Li Xinran , Zhang Simin , Chen Lincong , Fu Xiaotao , Geng Jianghai , Liu Yunpeng , Huang Qilin , Zhong Zheng
Published: June 2022

Abnormal heating of composite insulators of high-voltage transmission lines concentrate at its end, especially in a high-humidity environment. In order to study the influence of end-sheath aging and moisture absorption on abnormal heating of composite insulators, in this paper, we first discuss the appearance test, temperature rise test, and dielectric characteristic test conducted on 110 kV decommissioned composite insulators. Test results indicated the temperature rise in composite insulators increased with ambient humidity, but temperature rise was not severely affected by surface contamination of its shed and sheath; in dry environments, the dielectric constant and dielectric loss factor of high-voltage end sheaths are higher than of those of medium- and low-voltage end sheaths, and the loss effect becomes more severe after moisture absorption in a high-humidity environment. After the tests, the authors established a COMSOL simulation model of composite insulators, to analyze changes in the electric field and thermal field of the end sheath of composite insulators due to the coupling of electric and thermal fields. It was concluded that the dielectric constant of a high-voltage end sheath of the composite insulator increased after moisture absorption, distorting the partial electric field on the surface; meanwhile, the dielectric loss factor increased significantly after water molecules intruded into the aging layer of the sheath as polar molecules. Therefore, the dielectric loss (leakage conductance loss and lossy polarization loss) caused by aging and moisture absorption of the sheath surface under partially high field strength in the high-humidity environment was the leading cause of abnormal heating at the high-voltage end of composite insulators. The conclusion of this paper serves as an important reference for revealing the causes of abnormal heating of composite insulators in high-humidity environments and the influence mechanism of external factors on abnormal heating.
Improving the Surface Friction and Corrosion Resistance of Magnesium Alloy AZ31 by Ion Implantation and Ultrasonic Rolling
Authors: Dou Zhongyu , Jiang Haili , Ao Rongfei , Luo Tianye , Zhang Dianxi
Published: June 2022

The use of the magnesium alloy AZ31 is common in aviation and biomedicine; however, this alloy has poor friction and corrosion resistance. Here, mechanical grinding, ultrasonic rolling, and ultrasonic rolling + ion implantation were performed on the magnesium alloy surface to study the effect of the treatment process on the friction and corrosion resistance of the magnesium alloy surface. The results show that the surface roughness of the magnesium alloy treated by ultrasonic rolling + ion injection is reduced more than mechanical grinding and ultrasonic rolling. The friction coefficient is the lowest, the wear resistance is the best, and new phase nitrogen compounds appear on the surface. The results of SBF (simulated body fluid) solution immersion showed that the sample treated via this composite process had the lowest corrosion rate, which was 62.45% and 58.47% lower than that of the mechanically ground samples. The surface was relatively intact after the corrosion test, and the corrosion resistance was the best. These results can provide a new strategy for magnesium alloy surface protection.
Effect of Cold Rolling on the Microstructural Evolution and Mechanical Properties of Fe-25Mn-3Si-3Al-0.3Nb TWIP Steel
Authors: Li Dejun , Guo Jianhua , He Fei , Feng Yaorong , Guo Dashan , Ren Fengzhang , Cao Feng , Yang Qi , Shi Wei
Published: June 2022

The microstructural evolution, deformation mechanism and mechanical properties of Fe-25Mn-3Si-3Al-0.3Nb steel in the process of cold rolling were studied by optical microscopy, scanning microscopy, transmission electron microscopy, X-ray diffractometry, tensile testing and microhardness tests. A high-density dislocation structure and a small number of strain-induced twins appeared in the microstructure of the steel at 30% strain. At 50% strain, the strain-induced twins in austenite increased conspicuously, and the lamella thickness of the twins decreased. At 70% strain, the original grains were clearly refined by the micro-shear bands and twinning intersections to form a large number of sub-grains, and some sub-grains were at the nanoscale. The steel still remained a single-phase austenite during cold rolling even if the strain was as high as 70%. The plastic deformation mechanism of the steel was not changed through the addition of 0.3 wt.% Nb, and both dislocation slipping and twinning were still the fundamental plastic deformation mechanisms for the steel. Furthermore, cold rolling led to a drastic rise in the strength and hardness of the steel, but a remarkable decrease in the elongation. The characteristics of micropore aggregation fractures could always be observed on the fracture surface of static tensile specimens with various strains.
Digital Transformation of Signatures: Suggesting Functional Symmetry Approach for Loan Agreements
Authors: Titov Viktor , Shust Pavel , Dostov Victor , Leonova Anna , Krivoruchko Svetlana , Lvova Nadezhda , Guzov Iurii , Vashchuk Angelina , Pokrovskaia Natalia , Braginets Anton , Zaboev Mikhail
Published: June 2022

This article aims to formulate proposals for regulatory bodies whose implementation would ensure the effective introduction of civil circulation into electronic signatures, with minimal costs for economic entities. While electronic signatures have been widely discussed in academic literature, there are still gaps in the understanding of similarities and differences between electronic and handwritten signatures, the functional specifics of the relationship between them, and the role of electronic signatures for electronic contract. Our research has allowed us to overcome this gap adopting a functional symmetry approach based on measuring the distance between fuzzy sets and the Mamdani fuzzy inference algorithm. This made it possible to form an estimate of the degree of functional symmetry between different types of signatures in a fuzzy and exact form. Correspondingly, we argue that the signature can be viewed as a set of procedures rather than as a single act in order to achieve functional symmetry with a handwritten signature. The case of online lending was used to test and prove this hypothesis. Therefore, regulating electronic signatures needs to focus on the efficiency of this processes for ex ante identification, capturing the intent, ensuring the inalterability and providing reliable evidence, irrespective of the type of electronic signature that is used. It was also revealed that the proposed functional symmetry approach can be combined with a fuzziness index analysis to provide new prospects for further research.
Comparison of On-Policy Deep Reinforcement Learning A2C with Off-Policy DQN in Irrigation Optimization: A Case Study at a Site in Portugal
Authors: Alibabaei Khadijeh , Gaspar Pedro D. , Assunção Eduardo , Alirezazadeh Saeid , Lima Tânia M. , Soares Vasco N. G. J. , Caldeira João M. L. P.
Published: June 2022

Precision irrigation and optimization of water use have become essential factors in agriculture because water is critical for crop growth. The proper management of an irrigation system should enable the farmer to use water efficiently to increase productivity, reduce production costs, and maximize the return on investment. Efficient water application techniques are essential prerequisites for sustainable agricultural development based on the conservation of water resources and preservation of the environment. In a previous work, an off-policy deep reinforcement learning model, Deep Q-Network, was implemented to optimize irrigation. The performance of the model was tested for tomato crop at a site in Portugal. In this paper, an on-policy model, Advantage Actor–Critic, is implemented to compare irrigation scheduling with Deep Q-Network for the same tomato crop. The results show that the on-policy model Advantage Actor–Critic reduced water consumption by 20% compared to Deep Q-Network with a slight change in the net reward. These models can be developed to be applied to other cultures with high production in Portugal, such as fruit, cereals, and wine, which also have large water requirements.
The Impact of Maternal SARS-CoV-2 Infection Next to Pre-Immunization with Gam-COVID-Vac (Sputnik V) Vaccine on the 1-Day-Neonate’s Blood Plasma Small Non-Coding RNA Profile: A Pilot Study
Authors: Timofeeva Angelika V. , Fedorov Ivan S. , Chagovets Vitaliy V. , Zubkov Victor V. , Makieva Mziya I. , Sugak Anna B. , Frankevich Vladimir E. , Sukhikh Gennadiy T.
Published: June 2022

The antenatal and postnatal effects of maternal SARS-CoV-2 on the fetus outcomes, especially in the case of maternal pre-vaccination against this infection, are still under investigation. Such effects may be due to placental insufficiency caused by maternal hypoxia and inflammatory response associated with SARS-CoV-2, and/or be a direct cytopathic effect of the virus. In this work, we studied the profile of small non-coding RNAs (sncRNAs) in the blood plasma of a newborn from a mother who had SARS-CoV-2 at the 22nd week of gestation after immunization with Gam-COVID-Vac (Sputnik V). The fetus had ultrasound signs of hypertrophy of the right heart and hydropericardium 4 weeks after infection of the mother with SARS-CoV-2, as well as cysts of the cerebral vascular plexuses by the time of birth. Taking this into account, we compared the sncRNA profile of this newborn on the first postpartum day with that of neonates born to COVID-19-negative women with different perinatal outcomes: severe cardiovascular and/or neurological disorders, or absence of any perinatal complications. According to next-generation sequencing data, we found that the fetus born to a COVID-19-affected mother pre-immunized with Gam-COVID-Vac (Sputnik V) vaccine differs from newborns with severe cardiovascular and/or nervous system abnormalities either in multidirectional changes in circulating sncRNAs or in less pronounced unidirectional changes in the level of sncRNAs relative to control samples. Considering this, it can be concluded that maternal vaccination against SARS-CoV-2 before pregnancy has a protective effect in preventing antenatal development of pathological processes in the cardiovascular and nervous systems of the neonate associated with COVID-19.
Comparable Detection of SARS-CoV-2 in Sputum and Oropharyngeal Swab Samples of Suspected COVID-19 Patients
Authors: Akowuah Emmanuel , Acheampong Godfred , Ayisi-Boateng Nana Kwame , Amaniampong Andrews , Agyapong Francis Opoku , Senyo Kamasah Japhet , Agyei George , Owusu Dorcas Ohui , Nkrumah Bernard , Mutocheluh Mohamed , Sylverken Augustina Angelina , Owusu Michael
Published: June 2022

The accurate detection of SARS-CoV-2 through respiratory sampling is critical for the prevention of further transmission and timely initiation of treatment. There is a diverse range of SARS-CoV-2 detection rates in reported studies, with uncertainty regarding the optimal sampling method for COVID-19 diagnosis and monitoring. Oropharyngeal sampling (OPS) is one of the most commonly used methods of respiratory sampling in Ghana and other parts of the world for the detection of SARS-CoV-2 viral RNA. However, this sampling technique has a number of drawbacks, which include difficulty in obtaining high-quality swab samples, increased risk of infection to healthcare workers, and increased cost from a regular supply of swabs, transport media, and personal protective equipment (PPE). This study, therefore, sought to evaluate the diagnostic performance of sputum specimens in the diagnosis of COVID-19. This was a cross-sectional analytical study conducted in two health facilities in Kumasi, Ghana, between April and September 2021. Paired samples (an oropharyngeal swab and sputum) were taken from each recruited patient and run concurrently for the detection of SARS-CoV-2 genes (the N and ORF1ab genes) using RT-qPCR. Of the 317 patients recruited, 50.8% were males, and 60.4% were young adults aged 20–39 years. A significant proportion (65.9%) of the patients did not have any co-morbidity, and the majority were with symptoms; predominantly cough (36.3%), headache (31.5%), general weakness (24.0%), fever (20.2%), and sore throat (16.1%). Being symptomatic (p = 0.003), having comorbidity (p = 0.001), and the reporting facility (p = 0.010) were significantly associated with the COVID-19 status. The sputum samples yielded more COVID-positive, 120/317 (37.9%), as compared to OPS, 83/317 (26.2%). The sputum samples were 85.5% (95% CI, 76.4–91.5) sensitive, 79.1% (95% CI, 73.4–83.7) specific, and with positive and negative predictive values of 59.2% and 93.9%, respectively, when compared with OPS. The overall median of the SARS-CoV-2 viral loads for sputum (3.70 × 103 copies/mL) were significantly higher than in OPS (1.18 × 102 copies/mL) (p = 0.003). Findings from the study suggest self-collected sputum as a useful alternative to OPS for the diagnosis of COVID-19, providing a comparable diagnostic performance and, thereby, easing the uncomfortable process and mitigating risk of aerosol transmission to healthcare workers.
Annealing Engineering in the Growth of Perovskite Grains
Authors: Wang Lan , Liu Guilin , Xi Xi , Yang Guofeng , Hu Lifa , Zhu Bingjie , He Yifeng , Liu Yushen , Qian Hongqiang , Zhang Shude , Zai Huachao
Published: June 2022

Perovskite solar cells (PSCs) are a promising and fast-growing type of photovoltaic cell due to their low cost and high conversion efficiency. The high efficiency of PSCs is closely related to the quality of the photosensitive layer, and the high-quality light absorbing layer depends on the growth condition of the crystals. In the formation of high-quality crystals, annealing is an indispensable and crucial part, which serves to evaporate the solvent and drive the crystallization of the film. Various annealing methods have different effects on the promotion of the film growth process owing to the way they work. Here, this review will present a discussion of the growth puzzles and quality of perovskite crystals under different driving forces, and then explain the relationship between the annealing driving force and crystal growth. We divided the main current annealing methods into physical and chemical annealing, which has never been summarized before. The main annealing methods currently reported for crystal growth are summarized to visualize the impact of annealing design strategies on photovoltaic performance, while the growth mechanisms of thin films under multiple annealing methods are also discussed. Finally, we suggest future perspectives and trends in the industrial fabrication of PSCs in the future. The review promises industrial manufacturing of annealed PSCs. The review is expected to facilitate the industrial fabrication of PSCs.
Nucleation and Growth of an Ensemble of Crystals during the Intermediate Stage of a Phase Transition in Metastable Liquids
Authors: Toropova Liubov V. , Makoveeva Eugenya V. , Osipov Sergei I. , Malygin Alexey P. , Yang Yang , Alexandrov Dmitri V.
Published: June 2022

In this paper, an analytical method of solving the integro-differential system of kinetic and balance equations describing the evolution of an ensemble of crystals during the intermediate phase of the bulk crystallization process is described. The theory is developed for kinetic equations of the first- and second order corresponding to the absence and presence of fluctuations in particle growth rates. The crystal-size distribution function as well as the dynamics of metastability reduction in a supercooled melt (supersaturated solution) are analytically found using the saddle-point and the Laplace transform methods. The theory enables us to obtain the crystal-size distribution function that establishes in a supercooled (supersaturated) liquid at the beginning of the final stage of a phase transformation process when Ostwald ripening, coagulation and fragmentation of crystals are able to occur.
Enhancement Mode Ga2O3 Field Effect Transistor with Local Thinning Channel Layer
Authors: Ge Lei , Chen Qiu , Wang Shuai , Mu Wenxiang , Xin Qian , Jia Zhitai , Xu Mingsheng , Tao Xutang , Song Aimin
Published: June 2022

β−Ga2O3 field−effect transistors (FETs) were fabricated with and without local thinning to change the threshold voltage. A 220 nm Ga2O3 layer was mechanically exfoliated from a Cr−doped gallium oxide single crystal. Approximately 45 nm Ga2O3 was etched by inductively coupled plasma to form the local thinning. The threshold voltage of the device with etched local thinning increased from −3 V to +7 V compared to the unetched device. The effect of the local thinning was analyzed by device simulation, confirming that the local thinning structure is an effective method to enable enhancement−mode Ga2O3 FETs.
Phase Transitions in Amorphous Germanium under Non-Hydrostatic Compression
Authors: Xu Jianing , Zhang Lingkong , Wang Hailun , Gao Yan , Wei Tingcha , Susilo Resta , Zha Congwen , Chen Bin , Dong Hongliang , Chen Zhiqiang
Published: June 2022

As the pioneer semiconductor in transistor, germanium (Ge) has been widely applied in information technology for over half a century. Although many phase transitions in Ge have been reported, the complicated phenomena of the phase structures in amorphous Ge under extreme conditions are still not fully investigated. Here, we report the different routes of phase transition in amorphous Ge under different compression conditions utilizing diamond anvil cell (DAC) combined with synchrotron-based X-ray diffraction (XRD) and Raman spectroscopy techniques. Upon non-hydrostatic compression of amorphous Ge, we observed that shear stress facilitates a reversible pressure-induced phase transformation, in contrast to the pressure-quenchable structure under a hydrostatic compression. These findings afford better understanding of the structural behaviors of Ge under extreme conditions, which contributes to more potential applications in the semiconductor field.
Crystallization Kinetics of Basalt Glass-Ceramics Produced from Olivine Basalt Rock
Authors: Huo Yonglin , Qin Guilu , Huo Jichuan , Zhang Xingquan , Zhu Yongchang
Published: June 2022

Glass-ceramics acquired from the melting of rocks have a vast application marketplace. In this study, an olivine basalt rock from Zhangjiakou in China was selected as a raw material to prepare basalt glass-ceramics, and the crystallization kinetics of olivine basalt glass was investigated using differential thermal analysis. Polarizing microscope and X-ray diffraction (XRD) analysis results revealed that the main mineral compositions of olivine basalt are plagioclase, pyroxene, olivine, and iron oxide(s). Three crystallization peaks were observed in the DSC curve of the olivine basalt glass. The Avrami exponent (n), apparent activation energies for the crystallization, and glass transition of basalt glass were determined using the Owaza method based on data obtained from isothermal measurements. The crystallization activation energies (E) of the three crystallization peaks of olivine basalt glass were 314.20 kJ/mol, 1232.49 kJ/mol, and 696.89 kJ/mol, respectively. In addition to this, the crystal growth index indicated that the crystallization mode in the olivine basalt glass was surface crystallization. The crystallization phases and microstructure of the olivine basalt glass heated at 860 °C, 1100 °C, and 1180 °C were also studied. The conclusions obtained offer some useful information for the preparation of basalt glass-ceramics from olivine basalt rocks.