bluuebunny/crossref_metadata_2025 huggingface dataset:
Process Optimization, Microstructure and Mechanical Properties of Wire Arc Additive Manufacturing of Aluminum Alloy by Using DP-GMAW Based on Response Surface Method
Authors: Du Wenbo , Sun Guorui , Li Yue , Chen Chao
Published: August 2023

Double-pulsed gas metal arc welding (DP-GMAW) is a high-performance welding method with low porosity and high frequency. Periodic shrinkage and expansion of the melt pool during DP-GMAW leads to unusual remelting, and the re-solidification behavior of the weld metal can significantly refine the weld structure. The advantages of DP-GMAW have been proven. In order to better apply DP-GMAW to aluminum alloy arc additive manufacturing, in this paper, the single-pass deposition layer parameters (double-pulse amplitude, double-pulse frequency and travel speed) of DP-GMAW will be optimized using the response surface method (RSM) with the width, height, and penetration of the deposition layer as the response values to find the superior process parameters applicable to the additive manufacturing of aluminum alloy DP-GMAW. The results show that the aluminum alloy components made by DP-GMAW additive are well formed. Due to the stirring of double-pulse arc and the abnormal remelting and solidification of metal, the microstructures in the middle and top areas show disordered growth. The average ultimate tensile strength of the transverse tensile specimen of the member can reach 175.2 MPa, and the elongation is 10.355%.
Optimizing Layer Thickness and Width for Fused Filament Fabrication of Polyvinyl Alcohol in Three-Dimensional Printing and Support Structures
Authors: Moradi Mahmoud , Karamimoghadam Mojtaba , Meiabadi Saleh , Rasool Shafqat , Casalino Giuseppe , Shamsborhan Mahmoud , Sebastian Pranav Kattungal , Poulose Arun , Shaiju Abijith , Rezayat Mohammad
Published: August 2023

Polyvinyl Alcohol (PVA) is frequently applied as a support material in 3D printing, especially in the crafting of intricate designs and projecting elements. It functions as a water-soluble filament, often paired with materials like ABS or PLA. PVA serves as a momentary scaffold, supporting the jutting segments of a 3D model throughout the printing process. Subsequent to printing, the primary component can be effortlessly isolated by dissolving the PVA support using water. PVA, being a pliable and eco-friendly polymer, is susceptible to moisture. Its aqueous solubility renders it a prime selection for bolstering 3D print structures. In this investigation, equivalent-sized samples were 3D printed utilizing an Ultimaker 3D printer to assess the potency of PVA-generated specimens. Tensile examinations were executed on each sample employing a testing apparatus. The durability of the specimens was notably impacted by the input parameters, specifically the stratum width and stratum thickness. Strength dwindled as stratum width increased, whereas it rose with augmented stratum thickness. A few specimens with heightened stratum width and compromised quality displayed subpar performance during the tensile assessment. The findings unveiled a peak tensile strength of 17.515 MPa and a maximum load of 1600 N. Attaining an optimal degree of material utilization led to a decrease in filament consumption by 8.87 g, all the while upholding a MTS (maximum tensile strength) of 10.078 MPa.
The Log-Bimodal Asymmetric Generalized Gaussian Model with Application to Positive Data
Authors: Martínez-Flórez Guillermo , Tovar-Falón Roger , Bolfarine Heleno
Published: August 2023

One of the most widely known probability distributions used to explain the probabilistic behavior of positive data is the log-normal (LN). Although the LN distribution is capable of adjusting data types, it is not always fully true that the model manages to adequately model the behavior of the response of interest since in some cases, the degree of skewness and/or kurtosis of the data are greater or less than those that the LN distribution can capture. Another peculiarity of the LN distribution is that it only fits unimodal positive data, which constitutes a limitation when dealing with data that present more than one mode (bimodality). On the other hand, the log-normal model only fits unimodal positive data and in reality there are multiple applications where the behavior of materials is bimodal. To fill this gap, this paper introduces a new probability distribution that is capable of fitting unimodal or bimodal positive data with a high or low degree of skewness and/or kurtosis. The new distribution is a generalization of the LN distribution. For the new proposal, its main properties are studied and the process of estimation of the parameters involved in the model is carried out from a classical perspective using the maximum likelihood method. An important feature of this distribution is the non-singularity of the Fisher information matrix, which guarantees the use of asymptotic theory to study the properties of the parameter estimators. A Monte Carlo type simulation study is carried out to evaluate the properties of the estimators and finally, an illustration is presented with a set of data related to the concentration of nickel in soil samples, allowing to show that the proposed distribution fits extremely well in certain situations.
Asymptotic Domain Decomposition Method for Approximation the Spectrum of the Diffusion Operator in a Domain Containing Thin Tubes
Authors: Amosov Andrey , Gómez Delfina , Panasenko Grigory , Pérez-Martinez Maria-Eugenia
Published: August 2023

The spectral problem for the diffusion operator is considered in a domain containing thin tubes. A new version of the method of partial asymptotic decomposition of the domain is introduced to reduce the dimension inside the tubes. It truncates the tubes at some small distance from the ends of the tubes and replaces the tubes with segments. At the interface of the three-dimensional and one-dimensional subdomains, special junction conditions are set: the pointwise continuity of the flux and the continuity of the average over a cross-section of the eigenfunctions. The existence of the discrete spectrum is proved for this partially reduced problem of the hybrid dimension. The conditions of the closeness of two spectra, i.e., of the diffusion operator in the full-dimensional domain and the partially reduced one, are obtained.
Stochastic Growth Models for the Spreading of Fake News
Authors: Di Crescenzo Antonio , Paraggio Paola , Spina Serena
Published: August 2023

The propagation of fake news in online social networks nowadays is becoming a critical issue. Consequently, many mathematical models have been proposed to mimic the related time evolution. In this work, we first consider a deterministic model that describes rumor propagation and can be viewed as an extended logistic model. In particular, we analyze the main features of the growth curve, such as the limit behavior, the inflection point, and the threshold-crossing-time, through fixed boundaries. Then, in order to study the stochastic counterparts of the model, we consider two different stochastic processes: a time non-homogeneous linear pure birth process and a lognormal diffusion process. The conditions under which the means of the processes are identical to the deterministic curve are discussed. The first-passage-time problem is also investigated both for the birth process and the lognormal diffusion process. Finally, in order to study the variability of the stochastic processes introduced so far, we perform a comparison between their variances.
Risk Assessment of Mining Heritage Reuse in Public–Private-Partnership Mode Based on Improved Matter–Element Extension Model
Authors: Yang Shan , Zhuo Shengyuan , Xu Zitong , Chen Jianhong
Published: August 2023

With the development and utilization of resources, mineral-resource cities face the dilemma of resource depletion, the environmental restoration of mines, and industrial transformation. Reusing their mining heritage is a good way for these cities to change their mono-industrial structure and vigorously develop successor industries. Due to the complexity of reusing mining heritage, introducing the “Public–Private-Partnership” (PPP) mode can be a good solution to the problems of the government’s mining heritage reuse, such as large capital investment and a long construction-cycle time. To accurately classify the risk of reuse of mining heritage in the PPP mode, 26 indicators are selected to construct the evaluation index system of mining heritage reuse in the PPP mode based on five aspects: social capital-side, contractor-side, government-side, civilian-side, and the natural environment. The path coefficients of the structural equation model are used to calculate the weights of the indicators. The improved matter–element extension model is constructed to evaluate the reuse of mining heritage in the PPP mode. The Jiaozuo-Centennial Mining Heritage Park project is the object of research for applying the model. The results show that the risk evaluation index system combines the risk factors from the stakeholders’ perspective. The risk-evaluation model of the mining heritage reuse PPP project is constructed based on the combination of the improved matter–element extension model, the calculation of the asymmetric closeness, and the structural equation modeling method, which solves the drawbacks of the traditional model, such as the difficulty of determining the weights of the indicators, the incomplete scope of the material element domains, and the poor calculation of the comprehensive correlation degree. The case analysis shows that the risk level of the Jiaozuo-Centennial Mining Heritage Park project is Level II. This aligns with the actual situation and verifies the feasibility of the risk-evaluation model applied to the actual project. The research in this paper fills the gap in the risk model of mining heritage reuse in the PPP mode, enriches the theoretical system of risk evaluation of mining heritage reuse projects, and provides reference significance for similar mining heritage development projects in the future.
Development of the Method of Averaging in Clifford Geometric Algebras
Authors: Shirokov Dmitry
Published: August 2023

We develop the method of averaging in Clifford (geometric) algebras suggested by the author in previous papers. We consider operators constructed using two different sets of anticommuting elements of real or complexified Clifford algebras. These operators generalize Reynolds operators from the representation theory of finite groups. We prove a number of new properties of these operators. Using the generalized Reynolds operators, we give a complete proof of the generalization of Pauli’s theorem to the case of Clifford algebras of arbitrary dimension. The results can be used in geometry, physics, engineering, computer science, and other applications.
Preface to the Special Issue on “Mathematical Methods for Computer Science”
Authors: Hua Zhongyun , Zhang Yushu
Published: August 2023

In the last few decades, the relationship between mathematics and algorithms has become increasingly important and influential in computer science [...]
Innovating and Pricing Carbon-Offset Options of Asian Styles on the Basis of Jump Diffusions and Fractal Brownian Motions
Authors: Qi Yue , Wang Yue
Published: August 2023

Due to CO2 emissions, humans are encountering grave environmental crises (e.g., rising sea levels and the grim future of submerged cities). Governments have begun to offset emissions by constructing emission-trading schemes (carbon-offset markets). Investors naturally crave carbon-offset options to effectively control risk. However, the research and practice for these options are relatively limited. This paper contributes to the literature in this area. Specifically, according to carbon-emission allowances’ empirical distributions, we implement fractal Brownian motions and jump diffusions instead of traditional geometric Brownian motions. We contribute to extending the theoretical model based on carbon-offset option-pricing methods. We innovate the carbon-offset options of Asian styles. We authenticate the options’ stochastic differential equations and analytically price the options in the form of theorems. We verify the parameter sensitivity of pricing formulas by illustrations. We also elucidate the practical implications of an emission-trading scheme.
Lobosteroids A–F: Six New Highly Oxidized Steroids from the Chinese Soft Coral Lobophytum sp.
Authors: Xia Zi-Yi , Sun Man-Man , Jin Yang , Yao Li-Gong , Su Ming-Zhi , Liang Lin-Fu , Wang Hong , Guo Yue-Wei
Published: August 2023

To explore the steroidal constituents of the soft coral Lobophytum sp. at the coast of Xuwen County, Guangdong Province, China, a chemical investigation of the above-mentioned soft coral was carried out. After repeated column chromatography over silica gel, Sephadex LH-20, and reversed-phase HPLC, six new steroids, namely lobosteroids A–F (1–6), along with four known compounds 7–10, were obtained. Their structures were determined by extensive spectroscopic analysis and comparison with the spectral data reported in the literature. Among them, the absolute configuration of 1 was determined by X-ray diffraction analysis using Cu Kα radiation. These steroids were characterized by either the presence of an α,β-α′,β′-unsaturated carbonyl, or an α,β-unsaturated carbonyl moiety in ring A, or the existence of a 5α,8α-epidioxy system in ring B, as well as diverse oxidation of side chains. The antibacterial bioassays showed that all isolated steroids exhibited significant inhibitory activities against the fish pathogenic bacteria Streptococcus parauberis FP KSP28, Phoyobacterium damselae FP2244, and Streptococcus parauberis SPOF3K, with IC90 values ranging from 0.1 to 11.0 µM. Meanwhile, compounds 2 and 6–10 displayed potent inhibitory effects against the vancomycin-resistant Enterococcus faecium bacterium G7 with IC90 values ranging from 4.4 to 18.3 µM. Therefore, ten highly oxidized steroids with strong antibacterial activities were isolated from the Chinese soft coral Lobophytum sp., which could be developed as new chemotypes of antibacterial drug leads.
Development and Validation of a Novel Risk Score for All-Cause Mortality Risk Stratification Prior to Permanent Pacemaker Implantation in Octogenarians or Older
Authors: Lin Hsuan-Ching , Hung Ming-Jui , Wang Chao-Hung , Chen Tien-Hsing , Chen Wei-Siang , Cheng Chi-Wen
Published: August 2023

Background and Objectives: The demand for permanent pacemaker (PPM) implantation for extremely old patients is increasing. Prior to implanting PPMs, life expectancy evaluation is essential but difficult. We aimed to develop and validate a scoring system for all-cause mortality risk stratification prior to PPM implantation in patients aged ≥80. Materials and Methods: A total of 210 patients aged ≥80 who received PPM implantation were included. Multivariable analysis was performed to assess the effects of different variables on all-cause mortality in a derivation cohort (n = 100). We developed the MELODY score for stratifying all-cause mortality prior to PPM implantation and tested the scoring system in a validation cohort (n = 102). Results: After 4.0 ± 2.7 years of follow-up, 54 patients (54%) had died. The 0.5-, 1- and 2-year all-cause mortality rates were 7%, 10% and 24%, respectively. The MELODY score based on body mass index <21 kg/m2 (HR: 2.21, 95% CI: 1.06–4.61), estimated glomerular filtration rate <30 mL/min/1.73 m2 (3.35, 1.77–6.35), length of hospitalization before PPM implantation >7 days (1.87, 1.02–3.43) and dyspnea as the major presenting symptom (1.90, 1.03–3.50) successfully distinguished patients at high risk of mortality. Patients with MELODY scores ≥3 had a higher risk of mortality compared to those with MELODY scores <3 (8.49, 4.24–17.00). The areas under the receiver operating characteristic curves in predicting 0.5, 1 and 2 years mortality rates were 0.86, 0.81 and 0.74, respectively. The predictive value of the model was confirmed in a validation cohort. Conclusions: The novel scoring system is a simple and effective tool for all-cause mortality risk stratification prior to PPM implantation in patients aged ≥80.
Role of Membrane–Solute Affinity Interactions in Carbamazepine Rejection and Resistance to Organic Fouling by Nano-Engineered UF/PES Membranes
Authors: Mahlangu Oranso Themba , Motsa Mxolisi Machawe , Hai Faisal Ibney , Mamba Bhekie Brilliance
Published: August 2023

In this study, polyethersulfone (PES) ultrafiltration (UF) membranes were modified with GO, Ag, ZnO, Ag-GO and ZnO-GO nanoparticles to improve carbamazepine removal and fouling prevention by making membrane surfaces more hydrophilic. The fabricated membranes were characterized for surface and cross-sectional morphology, surface roughness and zeta potential, as well as hydrophilicity, functional groups, surface tension parameters and water permeability Thereafter, the membranes were evaluated for their efficiency in removing MgSO4 and carbamazepine as well as antifouling properties. To understand the role of affinity interactions in rejection and fouling, membrane–solute adhesion energies (∆Gslm) were quantified based on the Lifshitz–van der Waals/acid–base method. Unlike previous studies, which have generalized fouling prevention to be due to improvements in hydrophilicity upon adding nanoparticles, this work further explored the role of surface tension components on rejection and fouling prevention. The addition of nanoparticles improved membrane hydrophilicity (77–62°), water permeability (11.9–17.7 Lm−2 h−1 bar−1), mechanical strength (3.46–4.11 N/mm2), carbamazepine rejection (30–85%) and fouling prevention (60–23% flux decline). Rejection and antifouling properties increased as ∆Gslm became more repulsive (i.e., less negative). Membrane modification reduced irreversible fouling, and the fouled membranes were cleaned by flushing with water. Fouling related more to membrane electron donor components (γ−), while the roles of electron acceptor (γ+) and Lifshitz–van der Waals components (γLW) were less important. This work provides more insights into the role of affinity interactions in rejection and fouling and how rejection and fouling mechanisms change with nanoparticle addition.
Low-Cycle Fatigue Behaviour of Titanium-Aluminium-Based Intermetallic Alloys: A Short Review
Authors: Ellard John J. M. , Mathabathe Maria N. , Siyasiya Charles W. , Bolokang Amogelang S.
Published: August 2023

Over the past decade, relentless efforts have brought lightweight high-temperature γ-TiAl-based intermetallic alloys into real commercialisation. The materials have found their place in General Electric’s (GE) high bypass turbofan aircraft engines for the Boeing 787 as well as in the PW1100GTF engines for low-pressure turbine (LPT) blades. In service, the alloys are required to withstand hostile environments dominated by cyclic stresses or strains. Therefore, to enhance the fatigue resistance of the alloys, a clear understanding of the alloys’ response to fatigue loading is pivotal. In the present review, a detailed discussion about the low-cycle fatigue (LCF) behaviour of γ-TiAl-based alloys in terms of crack initiation, propagation and fracture mechanisms, and the influence of temperature and environment on cyclic deformation mechanisms and the resulting fatigue life has been presented. Furthermore, a comprehensive discussion about modelling and prediction of the fatigue property of these alloys with regard to the initiation and propagation lives as well as the total fatigue life has been provided. Moreover, effective methods of optimising the microstructures of γ-TiAl-based alloys to ensure improved LCF behaviour have been elucidated.
Comparative Study on Combustion Behavior of Aluminum-Based Alloy Fuels and Aluminum Powder in Solid Propellants
Authors: Xin Haoyue , Wang Kun , Ren Hui , Jiao Qingjie
Published: August 2023

In order to reduce the ignition temperature and improve the combustion efficiency of aluminum powder, three aluminum-based alloy fuels, Al–Mg, Al–Zn, and Al–Si–Mg, were prepared by the atomization method. The oxidation, ignition, and combustion performance of alloy fuels were investigated, and the results showed that, using pure aluminum powder as a reference, the weight gain of alloy fuels increased from 10% to 84%, the reaction activation energy decreased from 582 kJ·mol−1 to 208 kJ·mol−1, the alloy fuels containing Mg had good ignition response, and aluminum-based alloy fuels showed high calorific value and efficient combustion as a whole. In order to investigate the combustion behavior of alloy fuels in the solid propellant, tests were conducted on the mechanics, safety, process, and combustion properties of propellant according to the national standard, and the test results showed that, compared with the propellant made of aluminum powder with same quality, the propellant made of alloy has better mechanical properties, higher frictional sensitivity, lower electrostatic sensitivity, comparable process performance, and increased combustion calorific value and combustion speed. Engine test results confirmed that Al–Zn and Al–Si–Mg alloy fuels could effectively improve the specific impulse efficiency of the solid propellant and reduced the residual rate of the engine.
Microstructure and Properties of Nonlinear Lap Joint of 6061 Aluminum Alloy by Friction Stir Welding
Authors: Qu Laipeng , Ma Ning , Xiao Xiao , Zhang Keke , Li Huijun
Published: August 2023

The microstructure and properties of non-linear friction stir welded lap joints of the AA6061-T6 aluminum alloy were investigated, with a particular focus on the influence of corner curvature on the formability and mechanical properties of the joints. The research results indicate that for the 6061-T6 aluminum alloy lap joint friction stir welding with a smaller radius (R < 7 mm), there is a more severe accumulation of welding material. When the radius exceeds 7 mm, good macroscopic joint formation can be achieved. Various regions at the joint corners are composed of α-Al and intermetallic precipitations β phases. The microstructure of the heat-affected zone (HAZ) appeared relatively coarse, the weld nugget zone (WNZ) had the finest grain, and partial dissolution of the β phase occurred. The grain size in the middle WNZ at the corner was larger than at the ends, and the grain size on the inner side of the corner was larger than on the outer side. The hardness distribution of the joint exhibited a “W” shape, with the lowest hardness in the inner HAZ. When R ≤ 7, with an increase in R, the shear strength of the friction stir welded joints increased, and then the change became relatively small. The maximum shear strength of the joint was 101.32 ± 6.89 MPa at R = 7, and the fracture mode was primarily a ductile mixed fracture.
Effect of Tempering Time on Carbide Evolution and Mechanical Properties of a Nb-V-Ti Micro-Alloyed Steel
Authors: Zhao Qian , Qiao Zhixia , Dong Ji
Published: August 2023

The evolution of the microstructure, the precipitation behavior, and the mechanical performances of Nb-V-Ti micro-alloyed steel prepared under different tempering time were studied using transmission electron microscopy (TEM), X-ray diffraction (XRD), and mechanical tests. It was found that the width of the martensite laths increases with the increasing tempering time. Several kinds of carbides, including M3C, M2C, M23C6, M7C3, and MC particles, were identified after tempering. The MC carbides remain stable during tempering, but the transformation behavior of other carbides was identified. The transformation sequence can be summarized as: M3C → M2C → M7C3 → M23C6. The strength decreases and the Charpy impact toughness increases gradually with the increase in the tempering time. The ultimate strength (UTS) decreases from 1231 to 896 MPa, and the yield strength (YS) decreases from 1138 to 835 MPa. The −40 °C Charpy impact toughness increases from 20 to 61 J as the tempering time increases from 10 min to 100 h. The evolution of carbides plays an important role in their mechanical performances.
Extending Density Phase-Field Simulations to Dynamic Regimes
Authors: Jacobson David , Kamachali Reza Darvishi , Thompson Gregory Bruce
Published: August 2023

Density-based phase-field (DPF) methods have emerged as a technique for simulating grain boundary thermodynamics and kinetics. Compared to the classical phase-field, DPF gives a more physical description of the grain boundary structure and chemistry, bridging CALPHAD databases and atomistic simulations, with broad applications to grain boundary and segregation engineering. Notwithstanding their notable progress, further advancements are still warranted in DPF methods. Chief among these are the requirements to resolve its performance constraints associated with solving fourth-order partial differential equations (PDEs) and to enable the DPF methods for simulating moving grain boundaries. Presented in this work is a means by which the aforementioned problems are addressed by expressing the density field of a DPF simulation in terms of a traditional order parameter field. A generic DPF free energy functional is derived and used to carry out a series of equilibrium and dynamic simulations of grain boundaries in order to generate trends such as grain boundary width vs. gradient energy coefficient, grain boundary velocity vs. applied driving force, and spherical grain radius vs. time. These trends are compared with analytical solutions and the behavior of physical grain boundaries in order to ascertain the validity of the coupled DPF model. All tested quantities were found to agree with established theories of grain boundary behavior. In addition, the resulting simulations allow for DPF simulations to be carried out by existing phase-field solvers.
A Mechanical Evaluation of a Robot-Assisted Cutting Cornea Based on Force Response
Authors: Zhang Qinran , Zhao Jingyu , Wang Sikai , Deng Shijing , Su Peng
Published: August 2023

The aim of this paper is to propose laws of trephine operation based on a robot-assisted cutting cornea in order to obtain better microsurgical effects for keratoplasty. Using a trephine robot integrated with a microforce sensor and a handheld trephine manipulator, robotic and manual experiments were performed, with porcine corneas as the test subjects. The effect of trephine operational parameters on the results reflected by the biomechanical response is discussed, and the parameters include linear velocity, rotating angle, and angular velocity. Using probability density functions, the distributions of the manual operational parameters show some randomness, and there is a large fluctuation in the trephine force during the experiments. The biomechanical response shows regular trends in the robotic experiments even under different parameters, and compared to manual trephination, the robot may perform the operation of trephine cornea cutting more stably. Under different operational parameters, the cutting force shows different trends, and the optimal initial parameters that result in better trephine effects can be obtained based on the trends. Based on this derived law, the operational parameters can be set in robotic trephination, and surgeons can also be specially trained to achieve a better microsurgical result.
Multilayered Functional Triboelectric Polymers for Self-Powered Wearable Applications: A Review
Authors: Kim Minsoo P.
Published: August 2023

Multifunctional wearable devices detect electric signals responsive to various biological stimuli and monitor present body motions or conditions, necessitating flexible materials with high sensitivity and sustainable operation. Although various dielectric polymers have been utilized in self-powered wearable applications in response to multiple external stimuli, their intrinsic limitations hinder further device performance enhancement. Because triboelectric devices comprising dielectric polymers are based on triboelectrification and electrostatic induction, multilayer-stacking structures of dielectric polymers enable significant improvements in device performance owing to enhanced interfacial polarization through dissimilar permittivity and conductivity between each layer, resulting in self-powered high-performance wearable devices. Moreover, novel triboelectric polymers with unique chemical structures or nano-additives can control interfacial polarization, allowing wearable devices to respond to multiple external stimuli. This review summarizes the recent insights into multilayered functional triboelectric polymers, including their fundamental dielectric principles and diverse applications.
Towards High Capacitive Performance of Chemically Deposited β-Ni(OH)2 Nanolamellae Electrode Films
Authors: Moonooswamy Kevin Radakishna , Es-Souni Mohammed
Published: August 2023

Nickel hydroxide β-Ni(OH)2 nanolamellae with high aspect ratios were grown via chemical bath deposition (CBD) on both smooth and textured nickel foil. Depending on bath composition and/or the presence of an additive, thin foam-like nanolamellae to stacked lamellae were obtained. The used CBD method is highly cost-effective, as it is faster and requires less chemicals than typical hydrothermal methods, and it is readily implementable for large-scale production. The influence of surface texture on the final morphology and its effect on capacitive performance was investigated. Herein, we show how subtle changes in the concentration can drastically influence the morphology, which, in turn, drastically impacts the supercapacitive performance of the electrode. Also, the use of a textured surface significantly impacts the morphology, with vastly better cycling performance than samples made on a relatively smooth substrate. The measured specific capacitance values of the best sample were 1961 Fg−1 at 5 mVs−1 and 1998 Fg−1 at 1 Ag−1 under potentiostatic and galvanostatic conditions, respectively. This sample also retained 100% of its initial specific capacitance when discharged at a very high current density of 40 Ag−1. These values are substantially enhanced compared to previously reported data using a nearly analogous method (CBD with higher reagent conc.), with our method, cost-wise, offering economic advantages relative to results obtained with similar materials and other methods (e.g., hydrothermal).
Customised Implant for Temporomandibular Joint: New Technique to Design and Stress Analysis to Balance the Loading at Both Ends
Authors: Tiwari Anubhav , Ahmed Ishfaq A. , Gupta Vijay Kumar , Haldkar Rakesh Kumar , Parinov Ivan A.
Published: August 2023

The temporomandibular joint (TMJ) is a critical joint for the opening and closing of the mouth. The generation of customised TMJs according to individuals’ dental anatomy is needed. Currently, the implants available on the market lack consideration of the patient’s dental anatomy. This leads to the creation of an imbalance in the reaction forces on both ends of the TMJ. This requires a slight structural change in the design parameters to give a solution. The purpose of this study is to propose a new design that includes the geometry and materials for a TMJ implant. Stress analysis was carried out on the TMJ to balance the reaction forces at both TMJ ends. A static analysis was performed using ANSYS Workbench, to compare the results of two customised designs of TMJ implants, in order to better balance the reaction forces at both ends. The model in the study showed that the reaction forces for both the patient-specific TMJ implants were nearly balanced. The reaction forces were better balanced, and almost equivalent to the intact conditions. The stresses in the mandible were more uniformly distributed in the customised design of the TMJ implant. The two types of design showed that the custom design took up less space in the patient’s region of surgery, making it a better option compared to a stock TMJ implant. The custom implant would allow faster patient rehabilitation, as the reaction forces would be close to those in intact conditions.
Application of 3D Bioprinting in Liver Diseases
Authors: Li Wenhui , Liu Zhaoyue , Tang Fengwei , Jiang Hao , Zhou Zhengyuan , Hao Xiuqing , Zhang Jia Ming
Published: August 2023

Liver diseases are the primary reason for morbidity and mortality in the world. Owing to a shortage of organ donors and postoperative immune rejection, patients routinely suffer from liver failure. Unlike 2D cell models, animal models, and organoids, 3D bioprinting can be successfully employed to print living tissues and organs that contain blood vessels, bone, and kidney, heart, and liver tissues and so on. 3D bioprinting is mainly classified into four types: inkjet 3D bioprinting, extrusion-based 3D bioprinting, laser-assisted bioprinting (LAB), and vat photopolymerization. Bioinks for 3D bioprinting are composed of hydrogels and cells. For liver 3D bioprinting, hepatic parenchymal cells (hepatocytes) and liver nonparenchymal cells (hepatic stellate cells, hepatic sinusoidal endothelial cells, and Kupffer cells) are commonly used. Compared to conventional scaffold-based approaches, marked by limited functionality and complexity, 3D bioprinting can achieve accurate cell settlement, a high resolution, and more efficient usage of biomaterials, better mimicking the complex microstructures of native tissues. This method will make contributions to disease modeling, drug discovery, and even regenerative medicine. However, the limitations and challenges of this method cannot be ignored. Limitation include the requirement of diverse fabrication technologies, observation of drug dynamic response under perfusion culture, the resolution to reproduce complex hepatic microenvironment, and so on. Despite this, 3D bioprinting is still a promising and innovative biofabrication strategy for the creation of artificial multi-cellular tissues/organs.
Seroprevalence of Infections with TORCH Agents in Romania: A Systematic Review
Authors: Radoi Cristiana Luiza , Zlatian Ovidiu , Balasoiu Maria , Giubelan Lucian , Stoian Andreea Cristina , Dragonu Livia , Neacsu Alexandru , Iliescu Dominic Gabriel
Published: August 2023

Maternal–fetal infectious pathology—notably the TORCH panel (Toxoplasma gondii, rubella, Cytomegalovirus, and herpes simplex viruses)—critically impacts maternal and neonatal health. This review collates data on the seroprevalence of IgG and IgM antibodies against TORCH agents in Romanian women, aiming to discern regional and population differences and identify risk factors. Twenty studies were included in the review, revealing variable seroprevalence rates across the country. Regions such as Moldavia and Banat showed higher anti-T. gondii IgG seroprevalence rates than Bihor, with notable declines in Banat. Rural, older, and multiparous women showed elevated T. gondii IgG rates. Anti-rubella vaccine introduction significantly reduced the prevalence of anti-rubella IgG antibodies, but recent vaccination coverage decreases raise concerns. CMV and HSV seroprevalence varied geographically, with rural areas generally showing higher CMV rates and HSV influenced by factors like education level and number of sexual partners. Concurrent seroprevalence of multiple TORCH components in some cases underscores potential common risk factors. This study highlights the importance of continuous monitoring and preventive measures such as vaccinations and awareness campaigns to mitigate the health impact on the pregnant population.
Phylogeographic Analysis of Soft-Rot-Causing Pectobacterium spp. Strains Obtained from Cabbage in Serbia
Authors: Jelušić Aleksandra , Scortichini Marco , Marković Sanja , Mitrović Petar , Iličić Renata , Stanković Slaviša , Popović Milovanović Tatjana
Published: August 2023

The aim of this study was to establish a link between genetic diversity and the geographic origin of Pectobacterium strains belonging to three species—P. carotovorum, P. versatile, and P. odoriferum—isolated from cabbage in Serbia by comparing their sequences with those of strains sourced from different hosts and countries in Europe, Asia, and North America. Phylogeographic relatedness was reconstructed using the Templeton, Crandall, and Sing’s (TCS) haplotype network based on concatenated sequences of the housekeeping genes dnaX, icdA, mdh, and proA, while pairwise genetic distances were computed by applying the p-distance model. The obtained TCS haplotype networks indicated the existence of high intra-species genetic diversity among strains of all three species, as reflected in the 0.2–2.3%, 0.2–2.5%, and 0.1–1.7% genetic distance ranges obtained for P. carotovorum, P. versatile, and P. odoriferum, respectively. Five new haplotypes (denoted as HPc1–HPc5) were detected among cabbage strains of P. carotovorum, while one new haplotype was identified for both P. versatile (HPv1) and P. odoriferum (HPo1). None of the TCS haplotype networks provided evidence of significant correlation between geographic origin and the determined haplotypes, i.e., the infection origin. However, as haplotype network results are affected by the availability of sequencing data in public databases for the used genes and the number of analyzed strains, these findings may also be influenced by small sample size.
Baicalin Weakens the Porcine ExPEC-Induced Inflammatory Response in 3D4/21 Cells by Inhibiting the Expression of NF-κB/MAPK Signaling Pathways and Reducing NLRP3 Inflammasome Activation
Authors: Zong Bingbing , Xiao Yong , Ren Mingxing , Wang Peiyi , Fu Shulin , Qiu Yinsheng
Published: August 2023

Porcine extraintestinal pathogenic Escherichia coli (ExPEC) is a leading cause of death in pigs and has led to considerable economic losses for the pig industry. Porcine ExPEC infections often cause systemic inflammatory responses in pigs, characterized by meningitis, arthritis, pneumonia, and septicemia. Baicalin has been reported to possess potent anti-inflammatory activity, but its function in porcine ExPEC remains unknown. The aim of this study was to explore the protective effect and mechanism of baicalin against the porcine ExPEC-induced inflammatory responses in 3D4/21 cells. After treatment with baicalin, the effects on cell damage, the level of pro-inflammatory cytokines, the expression of nuclear factor-κB (NF-κB)/mitogen-activated protein kinase (MAPK) signaling pathways, and the activation of NOD-like receptor protein 3 (NLRP3) inflammasomes were examined. Our results show that baicalin significantly reduced the damage to 3D4/21 cells infected with porcine ExPEC PCN033. Further study showed that baicalin significantly reduced the transcription and expression of pro-inflammatory cytokines such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-8 (IL-8). Furthermore, baicalin inhibited the phosphorylation of proteins such as P65, nuclear factor κB inhibitor α (IκBα), extracellular regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and P38 and reduced the expression levels of proteins such as NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), and caspase-1. These results reveal that baicalin reduced the damage to 3D4/21 cells by inhibiting the expression of NF-κB/MAPK signaling pathways and blocking NLRP3 inflammasome activation in 3D4/21 cells infected with porcine ExPEC. Taken together, these results suggest that baicalin may have potential as a medicine for the treatment of porcine ExPEC-infected pigs by regulating inflammatory responses. This study provides a novel potential pharmaco-therapeutic approach to preventing porcine ExPEC infection.
Study on Mechanical and Flow Properties of Cemented Sulfur Tailings Backfill Considering the Influence of Fiber Type, Fiber Content and Addition Method
Authors: Liu Wei , Yin Shenghua , Hou Yongqiang , Zhang Minzhe
Published: August 2023

Previous studies have confirmed that for cemented tailings backfill, mechanical properties are improved through the addition of fiber. However, for fiber-reinforced cemented sulfur tailings backfill (FRCSTB), physical and flow properties are still unknown. In this paper, the changes in fluidity, splitting tensile strength (STS) and uniaxial compressive strength (UCS) of cemented sulfur tailings backfill (CSTB) are analyzed in detail. Secondly, regarding the addition of glass fiber and polypropylene fiber, the changes in the fluidity, STS and UCS of the CSTB, resulting from the fiber length, fiber content and method of fiber addition used, were analyzed. Moreover, the relationship between the UCS and fiber content is established. Finally, the mechanism behind the influence of fiber and sulfur content on the mechanical properties of CSTB is revealed. The results indicate that with the increase in sulfur content, the fluidity of the tailings slurry exhibits exponential growth. During the process of increasing sulfur content, the UCS and STS of CSTB initially increase and then decrease, reaching maximum values at 12% sulfur content. Similarly, at a fiber content of 0.6%, the UCS and 28d STS of CSTB reach their maximum values. In terms of enhancing the mechanical properties of CSTB, the effectiveness of glass fibers surpasses that of polypropylene fibers. In addition, regarding the improvement of the UCS of CSTB, the mixed addition of fibers is obviously worse than that of fiber alone. However, in terms of enhancing the STS of CSTB, the mixed addition of fibers outperforms the single addition of polypropylene fiber. From a microscopic perspective, polypropylene and glass fiber are able to form strong cohesion with the cement–tailings matrix and effectively prevent the formation and expansion of pores and cracks.
Exploring a Novel Mexican Sign Language Lexicon Video Dataset
Authors: Martínez-Sánchez Víctor , Villalón-Turrubiates Iván , Cervantes-Álvarez Francisco , Hernández-Mejía Carlos
Published: August 2023

This research explores a novel Mexican Sign Language (MSL) lexicon video dataset containing the dynamic gestures most frequently used in MSL. Each gesture consists of a set of different versions of videos under uncontrolled conditions. The MX-ITESO-100 dataset is composed of a lexicon of 100 gestures and 5000 videos from three participants with different grammatical elements. Additionally, the dataset is evaluated in a two-step neural network model as having an accuracy greater than 99% and thus serves as a benchmark for future training of machine learning models in computer vision systems. Finally, this research provides an inclusive environment within society and organizations, in particular for people with hearing impairments.
Evaluation of the Road to Birth Software to Support Obstetric Problem-Based Learning Education with a Cohort of Pre-Clinical Medical Students
Authors: Hutchcraft Megan L. , Wallon Robert C. , Fealy Shanna M. , Jones Donovan , Galvez Roberto
Published: August 2023

Integration of technology within problem-based learning curricula is expanding; however, information regarding student experiences and attitudes about the integration of such technologies is limited. This study aimed to evaluate pre-clinical medical student perceptions and use patterns of the “Road to Birth” (RtB) software, a novel program designed to support human maternal anatomy and physiology education. Second-year medical students at a large midwestern American university participated in a prospective, mixed-methods study. The RtB software is available as a mobile smartphone/tablet application and in immersive virtual reality. The program was integrated into problem-based learning activities across a three-week obstetrics teaching period. Student visuospatial ability, weekly program usage, weekly user satisfaction, and end-of-course focus group interview data were obtained. Survey data were analyzed and summarized using descriptive statistics. Focus group interview data were analyzed using inductive thematic analysis. Of the eligible students, 66% (19/29) consented to participate in the study with 4 students contributing to the focus group interview. Students reported incremental knowledge increases on weekly surveys (69.2% week one, 71.4% week two, and 78.6% week three). Qualitative results indicated the RtB software was perceived as a useful educational resource; however, its interactive nature could have been further optimized. Students reported increased use of portable devices over time and preferred convenient options when using technology incorporated into the curriculum. This study identifies opportunities to better integrate technology into problem-based learning practices in medical education. Further empirical research is warranted with larger and more diverse student samples.
Stretchable Sensors: Novel Human Motion Monitoring Wearables
Authors: Cho Chia-Jung , Chung Ping-Yu , Tsai Ying-Wen , Yang Yu-Tong , Lin Shih-Yu , Huang Pin-Shu
Published: August 2023

A human body monitoring system remains a significant focus, and to address the challenges in wearable sensors, a nanotechnology-enhanced strategy is proposed for designing stretchable metal-organic polymer nanocomposites. The nanocomposite comprises reduced graphene oxide (rGO) and in-situ generated silver nanoparticles (AgNPs) within elastic electrospun polystyrene-butadiene-polystyrene (SBS) fibers. The resulting Sandwich Structure Piezoresistive Woven Nanofabric (SSPWN) is a tactile-sensitive wearable sensor with remarkable performance. It exhibits a rapid response time (less than three milliseconds) and high reproducible stability over 5500 cycles. The nanocomposite also demonstrates exceptional thermal stability due to effective connections between rGO and AgNPs, making it suitable for wearable electronic applications. Furthermore, the SSPWN is successfully applied to human motion monitoring, including various areas of the hand and RGB sensing shoes for foot motion monitoring. This nanotechnology-enhanced strategy shows promising potential for intelligent healthcare, health monitoring, gait detection, and analysis, offering exciting prospects for future wearable electronic products.
Hybrid Chitosan–TiO2 Nanocomposite Impregnated in Type A-2186 Maxillofacial Silicone Subjected to Different Accelerated Aging Conditions: An Evaluation of Color Stability
Authors: Al-Kadi Faten K. , Abdulkareem Jwan F. , Azhdar Bruska A.
Published: August 2023

This study explores the impact of the incorporation of a chitosan–TiO2 nanocomposite on the color stability of pigmented room-temperature vulcanization maxillofacial silicone under various accelerated aging conditions. Five hundred disk-shaped specimens were formed with type A-2186 silicone elastomer, and they were distributed into groups based on pigment types and nanoparticle treatments. The color difference (ΔE) was assessed using a colorimeter in the CIELAB color system before and after exposure to aging conditions, including UV-accelerated aging and outdoor weathering. ANOVA, Dennett’s T3, and Tukey HSD tests revealed significant color alterations across all silicone types, with the most pronounced being in the red-colored 3% chitosan specimens and the least pronounced being in the 2% TiO2 specimens that underwent UV-accelerated aging. Outdoor weathering consistently increased the ΔE values across all categories. This study suggests that while nanoparticles may offer some resistance against accelerated aging, they fall short in adequately defending against UV radiation during outdoor weathering.