bluuebunny/crossref_metadata_2025 huggingface dataset:
The Reaction Products of the Al–Nb–B2O3–CuO System in an Al 6063 Alloy Melt and Their Influence on the Alloy’s Structure and Characteristics
Authors: Zhang Chenggong , Ao Min , Zhai Jingyu , Shi Zhiming , Liu Huimin
Published: December 2022

To meet aero-engine aluminum skirt requirements, an experiment was carried out using Al–Nb–B2O3–CuO as the reaction system and a 6063 aluminum alloy melt as the reaction medium for a contact reaction, and 6063 aluminum matrix composites containing in situ particles were prepared with the near-liquid-phase line-casting method after the reaction was completed. The effects of the reactant molar ratio and the preheating temperature on the in situ reaction process and products were explored in order to determine the influence of in situ-reaction-product features on the organization and the qualities of the composites. Thermodynamic calculations, DSC analysis, and experiments revealed that the reaction could continue when the molar ratio of the reactants of Al–Nb–B2O3–CuO was 6:1:1:1.5. A kinetic study revealed that the Al thermal reaction in the system produced Al2O3 and [B], and the [B] atoms interacted with Nb to generate NbB2. With increasing temperature, the interaction between the Nb and the AlB2 produced hexagonal NbB2 particles with an average longitudinal size of 1 μm and subspherical Al2O3 particles with an average longitudinal size of 0.2 μm. The microstructure of the composites was reasonably fine, with an estimated equiaxed crystal size of around 22 μm, a tensile strength of 170 MPa, a yield strength of 135 MPa, an elongation of 13.4%, and a fracture energy of 17.05 × 105 KJ/m3, with a content of 2.3 wt% complex-phase particles. When compared to the matrix alloy without addition, the NbB2 and Al2O3 particles produced by the in situ reaction had a significant refinement effect on the microstructure of the alloy, and the plasticity of the composite in the as-cast state was improved while maintaining higher strength and better overall mechanical properties, allowing for industrial mass production.
Biomechanical Behavior of Narrow Dental Implants Made with Aluminum- and Vanadium-Free Alloys: A Finite Element Analysis
Authors: Zapata José Manuel , Leal Eduardo , Hunter Renato , de Souza Raphael Freitas , Borie Eduardo
Published: December 2022

Titanium (Ti) alloys used for narrow dental implants usually contain aluminum (Al) and vanadium (V) for improved resistance. However, those elements are linked to possible cytotoxic effects. Thus, this study evaluated the biomechanical behavior of narrow dental implants made with Al- and V-free Ti alloys by the finite element method. A virtual model of a partially edentulous maxilla received single implants (diameter: 2.7 and 2.9 mm; length: 10 mm) at the upper lateral incisor area, with respective abutments and porcelain-fused-to-metal crowns. Simulations were performed for each implant diameter and the following eight alloys (and elastic moduli): (1) Ti–6Al–4V (control; 110 GPa), (2) Ti–35Nb–5Sn–6Mo–3Zr (85 GPa), (3) Ti–13Nb–13Zr (77 GPa), (4) Ti–15Zr (113 GPa), (5) Ti–8Fe–5Ta (120 GPa), (6) Ti–26.88Fe–4Ta (175 GPa), (7) TNTZ–2Fe–0.4O (107 GPa), and (8) TNTZ–2Fe–0.7O (109 GPa). The implants received a labially directed total static load of 100 N at a 45° angle relative to their long axis. Parameters for analysis included the maximum and minimum principal stresses for bone, and von Mises equivalent stress for implants and abutments. Ti–26.88Fe–4Ta reaches the lowest maximum (57 MPa) and minimum (125 MPa) principal stress values, whereas Ti–35Nb–5Sn–6Mo–3Zr (183 MPa) and Ti–13Nb–13Zr (191 MPa) models result in the highest principal stresses (the 2.7 mm model surpasses the threshold for bone overload). Implant diameters affect von Mises stresses more than the constituent alloys. It can be concluded that the narrow implants made of the Ti–26.88Fe–4Ta alloy have the most favorable biomechanical behavior, mostly by mitigating stress on peri-implant bone.
Effects of Heat Treatment and Severe Surface Plastic Deformation on Mechanical Characteristics, Fatigue, and Wear of Cu-10Al-5Fe Bronze
Authors: Maximov Jordan , Duncheva Galya , Anchev Angel , Dunchev Vladimir , Argirov Yaroslav , Todorov Vladimir , Mechkarova Tatyana
Published: December 2022

Aluminium bronzes are widely used in various industries because of their unique properties, a combination of high strength, wear resistance, and corrosion resistance in aggressive environments, including seawater. In this study, the subject of comprehensive experimental research was Cu-10Al-5Fe iron-aluminium bronze (IAB) with β-transformation, received in the form of hot-rolled bars. The effects of different heat treatments (HT) and severe surface plastic deformation (SPD), conducted by diamond burnishing (DB) on the microstructure, surface integrity (SI), mechanical properties, low- and mega-cycle fatigue strength, and dry sliding wear resistance, were determined. Based on quantitative indicators, the applied heat treatments in combination with severe SPD were compared. Thus, the integral efficiency of the heat treatments was evaluated, and the heat treatments were correlated with the resulting properties and operational behaviour of Cu-10Al-5Fe IAB. For example, if the component is designed for rotational bending conditions, the combination of quenching at 920 °C in water, subsequent tempering at 300 °C for three hours, and DB provides maximum fatigue strength in both low-cycle and mega-cycle fatigue applications.
The Physical Properties and Crystallization Kinetics of Biocomposite Films Based on PLLA and Spent Coffee Grounds
Authors: Novák Jan , Běhálek Luboš , Borůvka Martin , Lenfeld Petr
Published: December 2022

In the context of today’s needs for environmental sustainability, it is important to develop new materials that are based on renewable resources and biodegrade at the end of their life. Bioplastics reinforced by agricultural waste have the potential to cause a revolution in many industrial applications. This paper reports the physical properties and crystallization kinetics of biocomposite films based on poly(L-lactic acid) (PLLA) and 10 wt.% of spent coffee grounds (SCG). To enhance adhesion between the PLLA matrix and SCG particles, a compatibilizing agent based on itaconic anhydride (IA)-grafted PLLA (PLLA-g-IA) was prepared by reactive extrusion using dicumyl peroxide (DCP). Furthermore, due to the intended application of the film in the packaging industry, the organic plasticizer acetyl tributyl citrate (ATBC) is used to improve processing and increase ductility. The crystallization behavior and thermal properties were observed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Crystallinity degree increased from 3,5 (neat PLLA) up to 48% (PLLA/PLLA-g-IA/ATBC/SCG) at the highest cooling rate. The physical properties were evaluated by tensile testing and dynamic mechanical analysis (DMA). The combination of the compatibilizer, SCG, and ATBC led to a synergistic effect that positively influenced the supramolecular structure, internal damping, and overall ductility of the composite films.
Stability Analysis of Thin-Walled Perforated Composite Columns Using Finite Element Method
Authors: Falkowicz Katarzyna
Published: December 2022

Open holes or cut-outs have been commonly used in composite structures for various engineering purposes. Those elements often demand perforation especially for weight reduction and to ease maintenance and servicing operations, for example, in aircraft wing ribs. This work presents a numerical study of the stability behavior of composite perforated columns subjected to a compressive load. Profiles were made of CFRP laminate and weakened by three types of cut-out. Four parameters, spacing ratio S/D0, opening ratio D/D0, hole shape and arrangement of layers, were selected to check their effect on the buckling load and postbuckling behavior of the tested channel profiles. To carry out the numerical analysis, the Abaqus software was used. The results obtained during the analysis helped to identify the best combination of tested parameters to obtain the highest critical load. The performed analysis show that the columns’ behavior is sensitive to configuration of composite, opening ratio and hole shape.
Effect of Hot Deformation Parameters on Heat-Treated Microstructures and Mechanical Properties of 300M Steel
Authors: Du Fei , Zhou Peng , Guo Peng , Li Cheng , Deng Lei , Wang Xinyun , Jin Junsong
Published: December 2022

The high strength of 300M steel originates from the heat treatment process after forging, but how hot deformation affects the heat-treated microstructure and mechanical properties is unclear. In this study, compression tests under different hot deformation parameters and post-deformation heat treatment experiments were carried out, and the martensite transformation process was investigated using in situ observation. The results show that the grain size of the specimen deformed at low temperature and high strain rate is smaller, and annealing twins will be formed. Both austenite grain boundaries and twin boundaries hinder the growth of martensite blocks, reducing the size of martensite units after heat treatment and thus resulting in higher yield strength. Besides, the mathematical models were established to describe the relationship between hot deformation parameters and grain size after deformation, martensite packet size and martensite block width, respectively, after heat treatment. The relationship between yield strength and hot deformation parameters was also analyzed. According to the results and models, the hot deformation parameters would be optimized more reasonably to improve the final mechanical properties of 300M steel forgings.
A Doubly Fmoc-Protected Aspartic Acid Self-Assembles into Hydrogels Suitable for Bone Tissue Engineering
Authors: Petropoulou Katerina , Platania Varvara , Chatzinikolaidou Maria , Mitraki Anna
Published: December 2022

Hydrogels have been used as scaffolds for biomineralization in tissue engineering and regenerative medicine for the repair and treatment of many tissue types. In the present work, we studied an amino acid-based material that is attached to protecting groups and self-assembles into biocompatible and stable nanostructures that are suitable for tissue engineering applications. Specifically, the doubly protected aspartic residue (Asp) with fluorenyl methoxycarbonyl (Fmoc) protecting groups have been shown to lead to the formation of well-ordered fibrous structures. Many amino acids and small peptides which are modified with protecting groups display relatively fast self-assembly and exhibit remarkable physicochemical properties leading to three-dimensional (3D) networks, the trapping of solvent molecules, and forming hydrogels. In this study, the self-assembling fibrous structures are targeted toward calcium binding and act as nucleation points for the binding of the available phosphate groups. The cell viability, proliferation, and osteogenic differentiation of pre-osteoblastic cells cultured on the formed hydrogel under various conditions demonstrate that hydrogel formation in CaCl2 and CaCl2-Na2HPO4 solutions lead to calcium ion binding onto the hydrogels and enrichment with phosphate groups, respectively, rendering these mechanically stable hydrogels osteoinductive scaffolds for bone tissue engineering.
Energy Management and Control in Multiple Storage Energy Units (Battery–Supercapacitor) of Fuel Cell Electric Vehicles
Authors: Sayed Khairy , Abdel-Khalek Sayed , Zakaly Hesham M. H. , Aref Mahmoud
Published: December 2022

This paper presents a new approach of energy management for a fuel cell electric vehicle traction system. This system includes a supercapacitor, a traction battery of valve-regulated sealed lead–acid type, a high-performance permanent magnet traction system, and a power electronics converter. Special attention was placed on the coordination for managing the flow of energy from several sources to treat the concerns of prolonged electric vehicle mileage and battery lifetime for drivetrains of electric vehicles. Connection to a supercapacitor in parallel with the electric vehicle’s battery affects electric vehicle battery lifetime and its range. The paper used a study case of an all-electric train, but the used methods can be applied on hybrid or electric train cases. Fuzzy logic control and proportional integral control methods were used to control the electric vehicle system. The results of these two control methods were examined and compared. The simulation results were compared between the proposed electric vehicle system and the traditional system to show the effectiveness of the proposed method. Comparison of waveforms was made with and without the supercapacitor. The proposed optimized energy management strategy could improve the overall performance of the hybrid system and reduce the power consumption.
Recycled Aggregates from Ceramic and Concrete in Mortar Mixes: A Study of Their Mechanical Properties
Authors: Rosado Santiago , Costafreda Jorge , Martín Domingo , Presa Leticia , Gullón Lidia
Published: December 2022

In recent decades, large amounts of construction and demolition waste (CDW) have been generated and accumulated throughout Europe, which is a challenge to manage and control nowadays. This work shows the results of a study carried out with samples of ceramic recycled aggregates (CRAs) and recycled concrete aggregates (RCAs) mixed with cement (C) in mortars. The main objective of this research is to demonstrate how, by adding CRAs and RCAs to a mixture of cement and natural aggregate (NA), it is possible to develop a high-strength mortar and achieve the best mixing ratio. To achieve these objectives, the characterization of the samples was initially carried out such as XRF, XRD and SEM. Next, tests were carried out on the products obtained, such as the consistency of the fresh mortar and the density of the specimens. Finally, a study of mechanical compressive strength was performed at 7, 28 and 200 days. The results show that although both CRAs and RCAs negatively affect the curing process of the specimens, it is possible to develop mortars with compressive strengths greater than 20 MPa. An obvious increase in mechanical compressive strengths was seen between 7 and 200 days of analysis. The results achieved in this research could be an important guide for the management of CDWs by local industries, thus favouring the development of the circular economy.
Tribological Properties of Ti-TiC Composite Coatings on Titanium Alloys
Authors: Zhevtun Ivan G. , Gordienko Pavel S. , Mashtalyar Dmitriy V. , Kulchin Yuriy N. , Yarusova Sofia B. , Nepomnyushchaya Valeria A. , Kornakova Zlata E. , Gribanova Sofia S. , Gritsuk Danil V. , Nikitin Alexander I.
Published: December 2022

The application of titanium and its alloys under friction conditions is severely restricted, owing to their poor wear resistance. The paper presents the results of studies of the composition, microstructure, and tribological properties of Ti-TiC-based composite coatings formed on titanium alloys by the electroarc treatment in an aqueous electrolyte using a graphite anode. It has been found that TiC grains have a different stoichiometry and do not contain oxygen. The grain size varies from hundreds of nanometers to tens of micrometers, and the micro-hardness of the treated surface reached the value of 29.5 GPa. The wear resistance of the treated surface increased approximately 40-fold, and the friction coefficient with steel decreased to 0.08–0.3 depending on the friction conditions. The formation of a composite material based on Ti-TiC will contribute to the effective protection of titanium alloys from frictional loads in engineering.
Effect of Optimization Software on Part Shape Accuracy and Production Times during Rough Milling of Aluminum Alloy
Authors: Ižol Peter , Brindza Jozef , Vrabeľ Marek , Demko Michal , Basilio Shander
Published: December 2022

Reducing production costs during machining processes can be implemented in several ways, including various methods of cutting parameters optimization. The aim of the described research was to evaluate the effectiveness of software that optimizes the NC (Numerical Control) code generated from a CAM (Computer Aided Manufacturing) system. The experiments were carried out in rough milling. For the experiment, a sample with five pockets was designed and fabricated using the original NC programs from the CAM system and optimized NC programs. Evaluated criteria were the impact on the accuracy of the produced surfaces and degree of production time savings. When using the optimization software, despite more intensive cutting conditions, deviations on the side surfaces of the pockets were reduced from 3 to 23%. On the horizontal surfaces, for two pockets, there was an increase in deviations of a maximum of 7.8%, and for the remaining three pockets, there was a decrease in deviations ranging from 8.3 to 36%. The optimized NC programs achieved time savings ranging from 12.8 to 15.9%. This knowledge is important for manufacturers, as it allows shortening production times and thereby reducing related costs.
Dynamic Community Detection Method of a Social Network Based on Node Embedding Representation
Authors: Zhang Bo , Mi Yifei , Zhang Lele , Zhang Yuping , Li Maozhen , Zhai Qianqian , Li Meizi
Published: December 2022

The node embedding method enables network structure feature learning and representation for social network community detection. However, the traditional node embedding method only focuses on a node’s individual feature representation and ignores the global topological feature representation of the network. Traditional community detection methods cannot use the static node vector from the traditional node embedding method to calculate the dynamic features of the topological structure. In this study, an incremental dynamic community detection model based on a graph neural network node embedding representation is proposed, comprising the following aspects. A node embedding model based on influence random walk improves the information enrichment of the node feature vector representation, which improves the performance of the initial static community detection, whose results are used as the original structure of dynamic community detection. By combining a cohesion coefficient and ordinary modularity, a new modularity calculation method is proposed that uses an incremental training method to obtain node vector representation to detect a dynamic community from the perspectives of coarse- and fine-grained adjustments. A performance analysis based on two dynamic network datasets shows that the proposed method performs better than benchmark algorithms based on time complexity, community detection accuracy, and other indicators.
Radiative MHD Nanofluid Flow Due to a Linearly Stretching Sheet with Convective Heating and Viscous Dissipation
Authors: Alrihieli Haifaa , Alrehili Mohammed , Megahed Ahmed M.
Published: December 2022

This article describes a two-dimensional steady laminar boundary layer flow and heat mass transfer caused by a non-Newtonian nanofluid due to a horizontally stretching sheet. The non-dimensional parameters take into consideration and regulate the effects of convective boundary condition, slip velocity, Brownian motion, thermophoresis and viscous dissipation. The thermal radiation, which affects the flow’s thermal conductivity and the nanofluid’s variable viscosity are also taken into consideration. We propose that a hot fluid could exist beneath the stretching sheet’s bottom surface, which could aid in warming the surface via convection. The physical boundary conditions are non-dimensionalized, as are the governing transport set of nonlinear partial differential equations. By using the shooting approach, numerical values for dimensionless velocity, temperature and nanoparticle concentration are achieved. Distributions of velocity, temperature and concentration are plotted against a number of newly important governing factors, and the outcomes are then provided in accordance with those graphs. Additionally, the local skin-friction coefficient, the local Sherwood number and the local Nusselt number are discussed in order to further clarify and thoroughly explain the current problem. In order to validate the numerical results, comparisons are made with previously published data in the literature. There is a really good accord. Additionally, the current work has implications in the nanofluid applications.
A Molecular Modeling Investigation of the Therapeutic Potential of Marine Compounds as DPP-4 Inhibitors
Authors: Antony Priya , Baby Bincy , Aleissaee Hamda Mohammed , Vijayan Ranjit
Published: December 2022

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by elevated levels of blood glucose due to insulin resistance or insulin-secretion defects. The development of diabetes is mainly attributed to the interaction of several complex pathogenic, genetic, environmental and metabolic processes. Dipeptidyl peptidase-4 (DPP-4) is a serine protease that cleaves X-proline dipeptides from the N-terminus of several polypeptides, including natural hypoglycemic incretin hormones. Inhibition of this enzyme restores and maintains glucose homeostasis, making it an attractive drug target for the management of T2DM. Natural products are important sources of bioactive agents for anti-T2DM drug discovery. Marine ecosystems are a rich source of bioactive products and have inspired the development of drugs for various human disorders, including diabetes. Here, structure-based virtual screening and molecular docking were performed to identify antidiabetic compounds from the Comprehensive Marine Natural Products Database (CMNPD). The binding characteristics of two shortlisted compounds, CMNPD13046 and CMNPD17868, were assessed using molecular dynamics simulations. Thus, this study provides insights into the potential antidiabetic activity and the underlying molecular mechanism of two compounds of marine origin. These compounds could be investigated further for the development of potent DPP-4 inhibitors.
Antioxidant Defense and Pseudoexfoliation Syndrome: An Updated Review
Authors: Mastronikolis Stylianos , Kagkelaris Konstantinos , Pagkalou Marina , Tsiambas Evangelos , Plotas Panagiotis , Georgakopoulos Constantinos D.
Published: December 2022

Oxidative stress (OS) affects the anterior ocular tissues, rendering them susceptible to several eye diseases. On the other hand, protection of the eye from harmful factors is achieved by unique defense mechanisms, including enzymatic and non-enzymatic antioxidants. The imbalance between oxidants and antioxidants could be the cause of pseudoexfoliation syndrome (PEXS), a condition of defective extracellular matrix (ECM) remodeling. A systematic English-language literature review was conducted from May 2022 to June 2022. The main antioxidant enzymes protecting the eye from reactive oxygen species (ROS) are superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), which catalyze the reduction of specific types of ROS. Similarly, non-enzymatic antioxidants such as vitamins A, E and C, carotenoids and glutathione (GSH) are involved in removing ROS from the cells. PEXS is a genetic disease, however, environmental and dietary factors also influence its development. Additionally, many OS products disrupting the ECM remodeling process and modifying the antioxidative defense status could lead to PEXS. This review discusses the antioxidative defense of the eye in association with PEXS, and the intricate link between OS and PEXS. Understanding the pathways of PEXS evolution, and developing new methods to reduce OS, are crucial to control and treat this disease. However, further studies are required to elucidate the molecular pathogenesis of PEXS.
A New Prediction Method for the Preload Drag Force of Linear Motion Rolling Bearing
Authors: Liu Lu , Chen Hu , Li Zhuang , Li Wan-Ping , Liang Yi , Feng Hu-Tian , Zhou Chang-Guang
Published: December 2022

Existing studies focusing on the prediction of the preload drag force of linear motion rolling bearing (LMRB) are mainly based on mathematical modeling and vibration signal analysis. Very few studies have attempted to predict the preload drag force of LMRB on the basis of the raceway morphology. A 50 km running test was performed on a LMRB to study the correlation between the preload drag force of the LMRB and the change in raceway morphology. The preload drag force variation was measured in six regions using a surface profiler on a preload drag force test bench. The variational law for raceway morphology was characterized using the surface roughness Ra, maximum peak-to-valley height Rt, fractal dimension D, and recurrence rate Rr. The correlations between these four parameters (Ra, Rt, D, and Rr) and the preload drag force were 0.645, 0.657, 0.718, and 0.722, respectively, based on the gray correlation method. Hence, Rr is recognized as the optimal characterization parameter. Through the Gaussian process regression model, a preload drag force prediction model was established. Using the recurrence rate Rr as the input parameter to develop the prediction model, the accuracies of the prediction results of the three sets are 93.75%, 98.5% and 98.8%, respectively. These results provide a new method for the monitoring and prediction of the degradation of the preload drag force of a LMRB based on rolling track topography.
Interactions between Natural Products—A Review
Authors: Rajčević Nemanja , Bukvički Danka , Dodoš Tanja , Marin Petar D.
Published: December 2022

Plant-based natural products have been used as a source for therapeutics since the dawn of civilization. According to the World Health Organization (WHO), more than 80% of the world’s population relies on traditional medicine for their primary healthcare. Numerous natural extracts, widely known in Traditional Chinese Medicine, Indian Ayurveda medicine and other practices, have led to the modern discovery and development of new drugs. Plants continuously interact with their environment, producing new compounds and ever-changing combinations of existing ones. Interestingly, some of the compounds have shown lower therapeutic activity in comparison to the extract they were isolated from. These findings suggest that the higher therapeutic activity of the source extract was due to the synergistic effect of several compounds. In other words, the total therapeutic potential of the extract cannot be explained only by the sum of its parts alone. In traditional medicine, most herbal remedies are based on a mixture of plants, and it is the interaction between different constituents that amplifies their therapeutic potential. Considering the significant influence traditional medicine has on human healthcare, knowing and studying the synergistic effect of compounds is paramount in designing smart therapeutic agents.
Dental Diseases Increase Risk of Aortic Arch Calcification Independent of Renal Dysfunction in Older Adults: Shenzhen Community Cohort Study
Authors: Yin Li , Zhang Zhengzhipeng , Xie Changming , Luo Dongling , He Wanbing , Huang Suli , Huang Hui
Published: December 2022

Many studies have documented that dental diseases were associated with an increased risk of cardiovascular diseases. Aortic arch calcification (AoAC) is a powerful predictor of cardiovascular diseases. However, whether the status of dental health is associated with AoAC is still unknown. 9463 participants over the age of 60 from Shenzhen community centers were included in the cross-sectional analysis. Physical examination data, blood biochemical tests, and AoAC scores calculated by chest radiography were collected and analyzed. Among them, 2630 participants were followed up for AoAC progression up to 36 months. Participants with AoAC suffered more tooth loss than those without AoAC (77.62% vs. 72.91%; p < 0.001). Association rule analysis suggested a strong association between dental diseases and AoAC. Tooth loss or decay increased the risk of AoAC progression (HR 1.459; 95%CI 1.284–1.658) after adjusting other risk factors including renal dysfunction. Dental diseases are potential predictors for AoAC in elderly people, which are independent of renal dysfunction.
Relationship between Occupational Metal Exposure and Hypertension Risk Based on Conditional Logistic Regression Analysis
Authors: Qian Huiling , Li Guangming , Luo Yongbin , Fu Xiaolei , Wan Siyu , Mao Xiaoli , Yin Wenjun , Min Zhiteng , Jiang Jinfeng , Yi Guilin , Tan Xiaodong
Published: December 2022

Occupational exposure is a significant source of metal contact; previous studies have been limited regarding the effect of occupational metal exposure on the development of hypertension. This study was conducted to assess the levels of exposure of certain metals (chromium (Cr), iron (Fe), manganese (Mn), and nickel (Ni)) in hypertensive and non-hypertensive workers and to assess the relationship between the risk of hypertension and metal exposure level. Our study included 138 hypertensive patients as case groups and 138 non-hypertensive participants as controls. The exposure risk level was divided according to the limit value after collecting and testing the metal dust in the workshop. Considering the influence of single- and poly-metal, single factor analysis and conditional logistic regression analysis of poly-metal were carried out. The results of the model indicated that the incidence of hypertension increased with an increase in Cr exposure level, and the risk of hypertension was 1.85 times higher in the highest exposure than in the lowest exposure (95% CI: 1.20–2.86, p < 0.05). Mn has the same effect as Cr. There was no significant correlation between Fe or Ni and hypertension. Our findings suggested that Cr and Mn exposure in the work environment might increase the risk of hypertension, while no effect of Fe and Ni on blood pressure was found. Prospective study designs in larger populations are needed to confirm our findings.
Simulation Study on the Structure Design of p-GaN/AlGaN/GaN HEMT-Based Ultraviolet Phototransistors
Authors: Wang Haiping , You Haifan , Yang Jiangui , Yang Minqiang , Wang Lu , Zhao Hong , Xie Zili , Chen Dunjun
Published: December 2022

This work investigates the impacts of structural parameters on the performances of p-GaN/AlGaN/GaN HEMT-based ultraviolet (UV) phototransistors (PTs) using Silvaco Atlas. The simulation results show that a larger Al content or greater thickness for the AlGaN barrier layer can induce a higher two-dimensional electron gas (2DEG) density and produce a larger photocurrent. However, they may also lead to a larger dark current due to the incomplete depletion of the GaN channel layer. The depletion conditions with various Al contents and thicknesses of the AlGaN layer are investigated in detail, and a borderline between full depletion and incomplete depletion was drawn. An optimized structure with an Al content of 0.23 and a thickness of 14 nm is achieved for UV-PT, which exhibits a high photocurrent density of 92.11 mA/mm, a low dark current density of 7.68 × 10−10 mA/mm, and a large photo-to-dark-current ratio of over 1011 at a drain voltage of 5 V. In addition, the effects of other structural parameters, such as the thickness and hole concentration of the p-GaN layer as well as the thickness of the GaN channel layer, on the performances of the UV-PTs are also studied in this work.
Design of a Differential Low-Noise Amplifier Using the JFET IF3602 to Improve TEM Receiver
Authors: Wang Shengjie , Zhao Yuqi , Sun Yishu , Wang Weicheng , Chen Jian , Zhang Yang
Published: December 2022

The observed data of transient electromagnetic (TEM) systems is often contaminated by various noises. Even after stacking averages or applying various denoising algorithms, the interference of the system noise floor cannot be eliminated fundamentally, which limits the survey capability and detection efficiency of TEM. To improve the noise performance of the TEM receiver, we have designed a low-noise amplifier using the current source long-tail differential structure and JFET IF3602 through analyzing the power spectrum characteristics of the TEM forward response. By the designed circuit structure, the JFET operating point is easy to set up. The adverse effect on the JFET differential structure by JFET performance differences is also weakened. After establishing the noise model and optimizing the parameters, the designed low-noise differential amplifier has a noise level of 0.60nV/Hz, which increases the number of effective data 2.6 times compared with the LT1028 amplifier.
Attachable Inertial Device with Machine Learning toward Head Posture Monitoring in Attention Assessment
Authors: Peng Ying , He Chao , Xu Hongcheng
Published: December 2022

The monitoring of head posture is crucial for interactive learning, in order to build feedback with learners’ attention, especially in the explosion of digital teaching that occurred during the current COVID-19 pandemic. However, conventional monitoring based on computer vision remains a great challenge in the multi-freedom estimation of head posture, owing to low-angle annotation and limited training accuracy. Here, we report a fully integrated attachable inertial device (AID) that comfortably monitors in situ head posture at the neck, and provides a machine learning-based assessment of attention. The device consists of a stretchable inertial sensing unit and a fully integrated circuit-based system, as well as mechanically compliant encapsulation. Due to the mechanical flexibility, the device can be seamlessly attach to a human neck’s epidermis without frequent user interactions, and wirelessly supports six-axial inertial measurements, thereby obtaining multidimensional tracking of individual posture. These head postures (40 types) are then divided into 10 rotation actions which correspond to diverse situations that usually occur in daily activities of teaching. Benefiting from a 2D convolutional neural network (CNN)-based machine learning model, their classification and prediction of head postures can be used to analyze and infer attention behavior. The results show that the proposed 2D CNN-based machine learning method can effectively distinguish the head motion posture, with a high accuracy of 98.00%, and three actual postures were successfully verified and evaluated in a predefined attention model. The inertial monitoring and attention evaluation based on attachable devices and machine learning will have potential in terms of learning feedback and planning for learners.
Trophoblast Migration with Different Oxygen Levels in a Gel-Patterned Microfluidic System
Authors: Ko Gun , Jeon Tae-Joon , Kim Sun Min
Published: December 2022

In the placenta, substances such as nutrients, oxygen, and by-products are exchanged between the mother and the fetus, and the proper formation of the placenta determines the success of pregnancy, including the growth of the fetus. Preeclampsia is an obstetric disease in which the incomplete formation of the placenta occurs, which is known to occur when there is an abnormality in the invasion of trophoblast cells. The invasion of trophoblast cells is controlled by oxygen concentration, and HIF-1α changes according to oxygen concentration, showing a difference in cell mobility. MMP-2 and MMP-9 are observed to be high in the endometrium involved in trophoblast invasion, and the expression is regulated according to the oxygen concentration. In this experiment, cell culture was conducted using a gel-patterned system with a hypoxic chamber. Before the chip experiment, the difference in the expression of MMP-2 and MMP-9 according to the oxygen concentration was confirmed using a hypoxia chamber. After that, trophoblast cells (HTR8/SVneo) and endothelial cells (HUVECs) were separated and cultured through a physical barrier through a hydrogel on a microfluidic chip. Cells were cultured in a hypoxic chamber under controlled oxygen levels. It was confirmed that the mobility of trophoblast cells in culture on the chip was upregulated in a hypoxic environment through oxygen control. This suggests that the formation of a hypoxic environment in the endometrium where the invasion of trophoblast cells occurs plays a role in increasing cell mobility.
Emiliania huxleyi—Bacteria Interactions under Increasing CO2 Concentrations
Authors: Barcelos e Ramos Joana , Ribeiro Susana Chaves , Schulz Kai George , Coelho Francisco José Riso Da Costa , Oliveira Vanessa , Cunha Angela , Gomes Newton Carlos Marcial , Brownlee Colin , Passow Uta , de Azevedo Eduardo Brito
Published: December 2022

The interactions established between marine microbes, namely phytoplankton–bacteria, are key to the balance of organic matter export to depth and recycling in the surface ocean. Still, their role in the response of phytoplankton to rising CO2 concentrations is poorly understood. Here, we show that the response of the cosmopolitan Emiliania huxleyi (E. huxleyi) to increasing CO2 is affected by the coexistence with bacteria. Specifically, decreased growth rate of E. huxleyi at enhanced CO2 concentrations was amplified in the bloom phase (potentially also related to nutrient concentrations) and with the coexistence with Idiomarina abyssalis (I. abyssalis) and Brachybacterium sp. In addition, enhanced CO2 concentrations also affected E. huxleyi’s cellular content estimates, increasing organic and decreasing inorganic carbon, in the presence of I. abyssalis, but not Brachybacterium sp. At the same time, the bacterial isolates only survived in coexistence with E. huxleyi, but exclusively I. abyssalis at present CO2 concentrations. Bacterial species or group-specific responses to the projected CO2 rise, together with the concomitant effect on E. huxleyi, might impact the balance between the microbial loop and the export of organic matter, with consequences for atmospheric carbon dioxide.
Effects of Isolated LAB on Chemical Composition, Fermentation Quality and Bacterial Community of Stipa grandis Silage
Authors: Liu Mingjian , Wang Yu , Wang Zhijun , Bao Jian , Zhao Muqier , Ge Gentu , Jia Yushan , Du Shuai
Published: December 2022

This study aimed to screen and identify lactic acid bacteria (LAB) strains from the Stipa grandis and naturally fermented silage, and assess their effects on the silage quality and bacterial community of Stipa grandis after 60 days of the fermentation process. A total of 38 LAB were isolated, and strains ZX301 and YX34 were identified as Lactiplantibacillus plantarum and Pediococcus pentosaceus using 16S rRNA sequences; they can normally grow at 10−30 °C, with a tolerance of pH and NaCl from 3.5 to 8.0 and 3 to 6.5%, respectively. Subsequently, the two isolated LAB and one commercial additive (Lactiplantibacillus plantarum) were added to Stipa grandis for ensiling for 60 days and recorded as the ZX301, YX34, and P treatments. The addition of LAB was added at 1 × 105 colony-forming unit/g of fresh weight, and the same amount of distilled water was sprayed to serve as a control treatment (CK). Compared to the CK treatment, the ZX301 and YX34 treatments exhibited a positive effect on pH reduction. The water-soluble carbohydrate content was significantly (p < 0.05) increased in ZX301, YX34, and P treatments than in CK treatment. At the genus level, the bacterial community in Stipa grandis silage involves a shift from Pantoea to Lactiplantibacillus. Compared to the CK treatment, the ZX301, YX34, and P treatments significantly (p < 0.05) increase the abundance of Pediococcus and Lactiplantibacillus, respectively. Consequently, the results indicated that the addition of LAB reconstructed microbiota and influenced silage quality. The strain ZX301 could improve the ensiling performance in Stipa grandis silage.
Siniperca chuatsi Rhabdovirus (SCRV)-Induced Key Pathways and Major Antiviral Genes in Fish Cells
Authors: Ke Fei , Meng Xian-Yu , Zhang Qi-Ya
Published: December 2022

Fish rhabdoviruses, including Siniperca chuatsi rhabdovirus (SCRV), are epidemic pathogens that harm fish aquaculture. To clarify the interactions between SCRV and its host and explore antiviral targets, the present study performed transcriptome analysis in a cultured S. chuatsi skin cell line (SCSC) after SCRV infection at 3, 12, 24, and 36 h post-infection (hpi). Comparison with control obtained 38, 353, 896, and 1452 differentially expressed genes (DEGs) in the detected time points, respectively. Further analysis of the Go terms and KEGG pathways revealed the key pathways “Cytokine-cytokine receptor interaction” and “interferon related pathways” in SCSC cells responding to SCRV infection. The significantly up-regulated genes in the pathways were also verified by qPCR. Furthermore, gene cloning and overexpression revealed that five interferon-stimulated genes (ISGs) IFI4407, IFI35, Viperin, IFIT1, and IFIT5 had the ability to inhibit SCRV replication in FHM (Fathead minnow) cells, especially an inhibition efficiency more than 50% was observed in IFI35 overexpressed cells. In summary, current study revealed the main innate immune pathways in S. chuatsi cells induced by SCRV infection and the major ISGs of S. chuatsi in controlling SCRV replication.
Comparative Life Cycle Assessment of Conventional and Dry Stack Tailings Disposal Schemes: A Case Study in Northern China
Authors: Wang Kun , Zhang Zheng , Zhu Liyi , Yang Xiuzhi , Chen Miao , Yang Chao
Published: December 2022

Alternative tailings disposal technologies can be effective solutions to mining waste safety and environmental problems. The current decision-making processes for tailings disposal schemes lack consideration of environmental impacts. Based on a case study of an open-pit iron mine in northern China, this study adopted the life cycle assessment (LCA) method to compare the environmental impacts of three tailings disposal schemes of conventional slurry disposal technology (CSDT), dry stack disposal technology (DSDT) by belt conveyance and DSDT by truck transport. The results indicated that (1) the environmental impacts of the CSDT scheme were lowest under the premise that water consumption was ignored; (2) the environmental impacts of the DSDT scheme by belt conveyance mainly originated from its transport process, indicating that the tailings storage facilities (TSFs) site planning could be crucial in design decision making; (3) the environmental impacts of the DSDT scheme by truck transport mainly originated from the energy consumption of dry stacking equipment; and (4) the DSDT scheme by truck transport was eventually found to be preferable and implemented in the case study, after comprehensively considering the LCA results, TSF safety and remaining capacity, and social and policy uncertainties. It is therefore recommended to conduct LCA of environmental impacts in the decision-making process for the sustainable design of TSFs.
Mud Crab’s Mottled, Deep-Blue Exoskeleton: Surface Morphology and Internal Microstructure
Authors: Inoue Tadanobu , Kitahara Erina , Hara Yuka , Nakazato Koji
Published: December 2022

The claws of the mud crab, Scylla serrata, are huge in comparison with its body size. Many bulges ranging from 5 to 23 μm in height and 90 to 146 µm in diameter were observed on the mottled, deep-blue exoskeleton surface of the mud crab’s claw. These cuticle bulges were closely related to irregularly present exocuticles on the surface layer of the exoskeleton’s cross section. The bulges exist between the exocuticles, and at the apex of these bulges was a tube that bundled many pore canals that penetrated the exoskeleton. This tube was thick (62–66 µm) near the inner side and narrowed (12–22 µm) toward the outer surface. On the other hand, the exocuticles had a heterogeneous tissue structure in a coarse region extending normally to the surface, with a diameter of 3 to 7 µm, and a dense region between them. Calcium concentrations were high in the dense region, and phosphorus and magnesium concentrations were high in the coarse region. As a result, the mechanical properties (hardness: H and modulus: Er) were distributed inside the exocuticle, and the mapping of H and Er using a nanoindentation test clarified the heterogeneity.
In Vitro Cytotoxic Effects and Mechanisms of Action of Eleutherine Isolated from Eleutherine plicata Bulb in Rat Glioma C6 Cells
Authors: Shinkai Victoria Mae Tsuruzaki , Sampaio Izana Marize Oliveira , dos Santos Eline Gomes , Galué-Parra Adan Jesús , Ferreira Dionisia Pelaes , Baliza Drielly Dayanne Monteiro Santos , Ramos Neidiane Farias , Pimenta Raphael Sanzio , Burbano Rommel Mario Rodriguez , Sena Chubert Bernardo Castro , Macchi Barbarella Matos , Ferreira Irlon Maciel , Silva Edilene Oliveira , do Nascimento José Luiz Martins
Published: December 2022

Gliomas are the most common primary malignant brain tumors in adults, and have a poor prognosis, despite the different types of treatment available. There is growing demand for new therapies to treat this life-threatening tumor. Quinone derivatives from plants have received increased interest as potential anti-glioma drugs, due to their diverse pharmacologic activities, such as inhibiting cell growth, inflammation, tumor invasion, and promoting tumor regression. Previous studies have demonstrated the anti-glioma activity of Eleutherine plicata, which is related to three main naphthoquinone compounds—eleutherine, isoeleutherine, and eleutherol—but their mechanism of action remains elusive. Thus, the aim of this study was to investigate the mechanism of action of eleutherine on rat C6 glioma. In vitro cytotoxicity was evaluated by MTT assay; morphological changes were evaluated by phase-contrast microscopy. Apoptosis was determined by annexin V–FITC–propidium iodide staining, and antiproliferative effects were assessed by wound migration and colony formation assays. Protein kinase B (AKT/pAKT) expression was measured by western blot, and telomerase reverse transcriptase mRNA was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Eleutherine reduced C6 cell proliferation in a dose-dependent manner, suppressed migration and invasion, induced apoptosis, and reduced AKT phosphorylation and telomerase expression. In summary, our results suggest that eleutherine has potential clinical use in treating glioma.
Effect of Copper Chelators via the TGF-β Signaling Pathway on Glioblastoma Cell Invasion
Authors: Kim Heabin , Jo Seonmi , Kim In-Gyu , Kim Rae-Kwon , Kahm Yeon-Jee , Jung Seung-Hyun , Lee Jei Ha
Published: December 2022

Glioblastoma multiforme (GBM) is a fast-growing and aggressive type of brain cancer. Unlike normal brain cells, GBM cells exhibit epithelial–mesenchymal transition (EMT), which is a crucial biological process in embryonic development and cell metastasis, and are highly invasive. Copper reportedly plays a critical role in the progression of a variety of cancers, including brain, breast, and lung cancers. However, excessive copper is toxic to cells. D-penicillamine (DPA) and triethylenetetramine (TETA) are well-known copper chelators and are the mainstay of treatment for copper-associated diseases. Following treatment with copper sulfate and DPA, GBM cells showed inhibition of proliferation and suppression of EMT properties, including reduced expression levels of N-cadherin, E-cadherin, and Zeb, which are cell markers associated with EMT. In contrast, treatment with copper sulfate and TETA yielded the opposite effects in GBM. Genes, including TGF-β, are associated with an increase in copper levels, implying their role in EMT. To analyze the invasion and spread of GBM, we used zebrafish embryos xenografted with the GBM cell line U87. The invasion of GBM cells into zebrafish embryos was markedly inhibited by copper treatment with DPA. Our findings suggest that treatment with copper and DPA inhibits proliferation and EMT through a mechanism involving TGF-β/Smad signaling in GBM. Therefore, DPA, but not TETA, could be used as adjuvant therapy for GBM with high copper concentrations.