Search Results (750)

Acute kidney injury (AKI) is defined as a quick and often reversible decline in renal performance, as shown by elevated creatinine or reduced urine volume. AKI is a common illness, particularly among hospitalized cases, and can be observed in up to 7% of hospital admissions and 30% of ICU admissions. This study was designed to explore the nephroprotective potential of eco-synthesized quercetin–selenium nanoparticles (QUR-SeNPs) against experimentally glycerol-induced rhabdomyolysis leading to AKI. Forty healthy adult male albino rats were employed in the experiment. Animals were randomly distributed equally into five groups: Control: orally administered with normal saline solution. GLY: orally administered with normal saline (0.9% NaCl) for 15 consecutive days, at day 14, animals of this group received a single dose of intramuscular (im.) injection of 50% glycerol (GLY) (10 mg/kg/day). GLY and quercetin (GLY&QUR): orally administered with quercetin daily for 15 days (50 mg/kg/day), at day 14, animals of this group received a single dose of im. injection of 50% glycerol (10 mg/kg/day). GLY&Na₂SeO₃: orally administered with sodium selenite daily for 15 days (0.5 mg/kg/day), at day 14, animals of this group received a single dose of im. injection of 50% glycerol (10 mg/kg/day). GLY&QUR-SeNPs: orally administered with selenium nanoparticles synthesized using quercetin daily for 15 days (0.5 mg/kg/day), at day 14, animals of this group received a single dose of im. injection of 50% glycerol (10 mg/kg/day). Oxidative stress, inflammatory, and apoptotic markers, in addition to histopathological, gene expression, and immunohistochemical analysis, were assessed for all groups. The results demonstrated that QUR-SeNPs effectively ameliorated renal functional, biochemical, and molecular disturbances through their synergistic antioxidant, anti-inflammatory, and anti-apoptotic potential, surpassing the effects of either quercetin or selenium alone. Biosynthesized selenium nanoparticles using QUR-SeNPs demonstrated remarkable nephroprotective activity by normalizing renal biomarkers, restoring antioxidant capacity, inhibiting inflammatory cytokines, and preventing apoptotic damage. The nanoparticle formulation exhibited superior efficacy to either QUR or Se alone, highlighting the synergistic interplay between selenium and quercetin through enhanced bioavailability, redox stability, and molecular targeting. Full article

Installation in sand is sensitive to its evolving pore structure, yet design models rarely update permeability for real-time fabric changes. This study tracks the stress-dependent pore size distribution of coarse sand under laterally constrained compression using high-resolution X-ray nano-CT. Scans taken at six axial stress levels show that the distribution shifts toward smaller radii while keeping its log-normal shape. A single shifting factor, defined as the current median radius normalized by the initial value, captures this translation. The factor decays with axial stress according to a power law, and the exponent as well as the reference pressure are calibrated from void ratio data. The resulting closed-form expression links mean effective stress to pore radius statistics without extra fitting once the compressibility constants are known. This quantitative relation between effective stress and pore size distribution has great potential to be embedded into coupled hydro-mechanical solvers, enabling engineers to refresh hydraulic permeability at every computation step, improving predictions of excess pore pressure and soil resistance during suction anchor penetration for floating wind foundations. Full article

The rise in thermal runaway events within electric vehicle (EV) battery systems requires anticipatory models to predict critical safety failures during operation. This investigation develops a multi-physics digital twin framework that links electrochemical, thermal, and structural domains to replicate the internal dynamics of lithium-ion packs in both normal and faulted modes. Coupled simulations distributed among MATLAB 2024a, Python 3.12-powered three-dimensional visualizers, and COMSOL 6.3-style multi-domain solvers supply refined spatial resolution of temperature, stress, and ion concentration profiles. While the digital twin architecture is designed to accommodate different battery chemistries and pack configurations, the numerical results reported in this study correspond specifically to a lithium NMC-based 4S3P cylindrical cell module. Quantitative benchmarks show that the digital twin identifies incipient thermal deviation with 97.4% classification accuracy (area under the curve, AUC = 0.98), anticipates failure onset within a temporal margin of ±6 s, and depicts spatial heat propagation through three-dimensional isothermal surface sweeps surpassing 120 °C. Mechanical models predict casing strain concentrations of 142 MPa, approaching polymer yield strength under stress load perturbations. A unified operator dashboard delivers diagnostic and prognostic feedback with feedback intervals under 1 s, state-of-health (SoH) variance quantified by a root-mean-square error of 0.027, and mission-critical alerts transmitting with a mean latency of 276.4 ms. Together, these results position digital twins as both diagnostic archives and predictive safety envelopes in the evolution of next-generation EV architectures. Full article

The paper is concerned with experimental investigations and numerical simulations of airflow in a rigid model of human tracheal bifurcation during a respiratory cycle in the presence of cough. The main goal of the study is to calculate the velocity and tracheal wall shear stress (WSS) distributions under the time variation in the pressure difference. A sequence of inspiration-expiration of measured flow rates and pressure is used to calibrate the 3D unsteady numerical solutions for different imposed boundary conditions at the edges of the bifurcation. The experimental data are obtained using commercial medical devices: (i) a spirometer and (ii) a mechanical ventilator, respectively. CT images of the lung airways were used to reconstruct the tracheal test geometry by 3D printing techniques. Flow spectrum, vortical structures, and the wall stresses are analyzed for the computed cases. Four turbulence models (k − ɛ, k − ω SST, k − ɛ R, and LES) are compared, and all indicate an increase in peak WSS and vortex intensity during coughing versus normal expiration. The present work confirms the importance of CFD simulations to model and quantify airflow throughout the respiratory cycle. The paper proposes a method to calculate wall shear stress, one of the most relevant parameters for characterizing airway function and the mechanical response of tracheal endothelial cells. Full article

To obtain fatigue crack propagation properties of ordinary concrete commonly employed in bridge construction, 48 replicate single-edge notched beam specimens were fabricated using C50 plain concrete. Twelve of these were subjected to monotonic loading to determine their static capacity; the remaining 36 were fatigue-loaded with various combinations of maximum stress level and stress ratio under three-point bending. Visual observation, strain gauges, and the compliance method were used to determine the evolution of crack length during fatigue loading. The fatigue crack growth rates were then evaluated for each specimen using linear regression. This study shows that the fracture surface under fatigue loading exhibits greater zigzagging than under monotonic loading, with multiple microcracks coalescing. The elastic compliance method captures the three-stage development of fatigue crack well, and the derived equivalent crack size is consistently smaller than surface measurements. Significant scatter exists in the test data; however, the crack growth rate and stress intensity factor range follow a straight line on logarithmic scales, indicating that the Paris Law applies to plain concrete. The slope and intercept of C50 concrete, based on 27 fatigue-failed specimens, follow a Normal distribution, with means of 16.46 and −24.81 (in N-mm units), and coefficients of variation of 0.38 and −0.38, respectively. The corresponding mean and coefficient of variation for slope and intercept by the Forman Equation are 14.80 and 0.42 and −21.18 and −0.44, respectively. The fatigue crack in C50 concrete of this study shows a faster growth rate (46.7% larger slope) than that in lower-strength concrete in the literature. With further research needs identified, this study contributes to a better understanding of the fatigue crack growth properties of ordinary structural concrete, providing valuable information for fatigue assessment and service-life extension of existing concrete bridges. Full article

To study the mechanical properties and displacement evolution of rock masses near coal-seam normal faults under mining disturbances; this paper utilizes fiber optic monitoring and distributed strain measurement techniques to achieve the fine monitoring of the entire process of stress–displacement–strain during mining. The experimental design adopts a stepwise mining approach to systematically reproduce the evolution of fault formation; slip; and instability. The results show that the formation of normal faults can be divided into five stages: compressive deformation; initiation; propagation; slip; and stabilization. The strength of the fault plane is significantly influenced by the dip angle. As the dip angle increases from 30° to 70°, the peak strength decreases by 23%, and the failure mode transitions from tensile failure to shear failure. Under mining disturbances, the stress field in the overlying rock shifts from concentration to dispersion, with a stress mutation zone appearing in the fault-adjacent area. During unloading, vertical stress decreases by 45%, followed by a rebound of 10% as mining progresses. The rock layers above the goaf show significant subsidence, with the maximum vertical displacement reaching 150 mm. The displacement between the hanging wall and footwall differs, with the maximum horizontal displacement reaching 78 mm. The force chain distribution evolves from being dominated by compressive stress to a compressive–tensile stress coupling state. The fault zone eventually enters a stress polarization state and tends toward instability. A large non-uniform high-speed zone forms at the fault cutting point in the velocity field, revealing the mechanisms of fault instability and the initiation of dynamic disasters. These experimental results provide a quantitative understanding of the multi-physics coupling evolution characteristics of coal-seam normal faults under mining disturbances. The findings offer theoretical insights into the instability of coal-seam normal faults and the mechanisms behind the initiation of dynamic disasters. Full article

The evolution of Smart Grids enabled the deployment of intelligent and decentralized energy management solutions at the residential level. This work presents a comprehensive Smart Home architecture that integrates real-time energy monitoring, appliance-level consumption analysis, and environmental data acquisition using smart metering technologies and distributed IoT sensors. All collected data are structured into a scalable infrastructure that supports advanced Artificial Intelligence (AI) methods, including Large Language Models (LLMs) and machine learning, enabling predictive analysis, personalized energy recommendations, and natural language interaction. Proposed architecture is experimentally validated through a case study on a domestic refrigerator. Two series of tests were conducted. In the first phase, extreme usage scenarios were evaluated: one with intensive usage and another with highly restricted usage. In the second phase, normal usage scenarios were tested without AI feedback and with AI recommendations following them whenever possible. Under the extreme scenarios, AI-assisted interaction resulted in a reduction in daily energy consumption of about 81.4%. In the normal usage scenarios, AI assistance resulted in a reduction of around 13.6%. These results confirm that integrating AI-driven behavioral optimization within Smart Home environments significantly improves energy efficiency, reduces electrical stress, and promotes more sustainable energy usage. Full article

Background: Realistic simulation of ECG signals is essential for validating signal-processing algorithms and training artificial intelligence models in cardiology. Many existing approaches model either waveform morphology or heart rate variability (HRV), but few achieve both with high accuracy. This study proposes a hybrid method that combines morphological accuracy with physiological variability. Methods: We developed a mathematical model that integrates Gaussian mesa functions (GMF) for waveform generation and a chaotic Rössler attractor to simulate RR-interval variability. The GMF approach allows fine control over the amplitude, width, and slope of each ECG component (P, Q, R, S, T), while the Rössler system introduces dynamic modulation through the use of seven parameters. Spectral and statistical analyses were applied, including power spectral density (PSD) computed via the Lomb–Scargle, STFT, CWT, and histogram analyses. Results: The synthesized signals demonstrated physiological realism in both the time and frequency domains. The LF/HF ratio was 1.5–2.0 when simulating a normal rhythm and outside these limits in a simulated stress rhythm, consistent with typical HRV patterns. PSD analysis captured clear VLF (0.003–0.04 Hz), LF (0.04–0.15 Hz), and HF (0.15–0.4 Hz) bands. Histogram distributions showed amplitude ranges consistent with real ECGs. Conclusions: The hybrid GMF–Rössler approach enables large-scale ECG synthesis with controllable morphology and realistic HRV. It is computationally efficient and suitable for artificial intelligence training, diagnostic testing, and digital twin modeling in cardiovascular applications. Full article

Background/Objectives: Relapsing-remitting multiple sclerosis (RRMS) is a chronic neurological disease that significantly impacts health-related quality of life (HRQoL). This study aimed to analyze the evolution of HRQoL in individuals with RRMS, identify associated factors, and determine predictive variables. Methods: A prospective observational study was conducted with 35 participants diagnosed with RRMS at the Lucus Augusti University Hospital between January 2023 and March 2025. HRQoL was assessed using the MSQOL-54 questionnaire at baseline, 3 months, and 6 months. Data were analyzed using non-parametric tests to account for the small sample size and non-normal distribution of the variables. Results: Results showed overall stability in HRQoL (mean score: 62.4 ± 14.1 at baseline, 62.8 ± 12.7 at 3 months, and 62.4 ± 11.8 at 6 months), although significant declines were observed in emotional limitations (64.4 ± 23.0 at baseline to 58.9 ± 20.5 at 6 months) and social functioning (70.5 ± 16.7 at baseline to 65.5 ± 12.8 at 6 months). Improvements were noted in pain perception (78.9 ± 23.6 at baseline to 81.8 ± 20.5 at 6 months) and stress (44.3 ± 22.5 at baseline to 48.9 ± 17.8 at 6 months). Factors such as family history (associated with mental health at diagnosis, p = 0.028), autoimmune diseases (associated with physical function at diagnosis, p = 0.035), and lifestyle habits (e.g., tobacco use associated with physical limitations at 3 months, p = 0.045) were significantly associated with HRQoL. Baseline HRQoL emerged as a strong predictor of future scores (Spearman’s correlations, p < 0.01), indicating that early assessments may guide interventions. Conclusions: Although overall HRQoL remains stable in RRMS, specific domains such as emotional and social functioning exhibit progressive decline, highlighting the need for tailored interventions. The findings underscore the importance of integrating early psychosocial support and lifestyle interventions into routine care to mitigate vulnerabilities in emotional and social domains of HRQoL. Full article

Drop hammer impact tests were conducted to study crack features and the ductile–brittle transition in sea ice under low-speed impact. Crack images were analyzed using Hessian filtering and Hough transform methods, and a finite element model was created. Material parameters were validated using the crack tip strength factor. Energy dissipation, focusing on kinetic energy, was analyzed to understand energy conversion and crack propagation in sea ice during low-speed impact. The results indicate that the angular distribution of the crack mode exhibits central symmetry, with the peak frequency at each angle approximately 5°. As the initial impact kinetic energy increases, the dynamic response of the sea ice plate transitions from toughness to brittleness; the kinetic energy dissipation increases linearly, while its utilization efficiency declines. The variation in the kinetic energy conversion rate (η) is associated with the mode of ice plate failure. The crack propagation rate follows a normal distribution in relation to changes in time and kinetic energy. The stress wave effect predominates in the fracture formation mode, further elucidating the ductile–brittle transition behavior of sea ice. This research holds significant implications for ice-breaking operations. Full article

Based on the Hilbert–Riemann theory, this paper develops a simplified model to address interfacial fracture in bi-layer laminated solar cells with significantly dissimilar thermal properties. The model is used to analyze interfacial normal stress distributions and identify critical stress points, taking into account the substantial mismatch in the coefficients of thermal expansion between the semiconductor and encapsulation layers. The predicted temperature and stress fields are validated through finite element simulations. Furthermore, by investigating commonly used encapsulation films and solar cell modules, the coupled effects of the thermal expansion coefficient and elastic modulus are elucidated. The results demonstrate that, under a constant layer thickness, the position of the stress critical point is governed by two dimensionless parameters: the ratio of thermal expansion coefficients and the ratio of elastic moduli. This work offers an efficient and practical approach for predicting thermal stress concentration trends in laminated solar cell structures, thereby providing useful insights for the design and fabrication of solar modules. Full article

Defects in pipes adversely affect both the jacking construction process and long-term operational safety, yet their specific impacts on mechanical properties remain unclear. This study investigates pipe jacking segments under deflection, using the Changsha Meixi Lake project as a case study. Similar model tests combined with digital image correlation were employed to examine the evolution of stress and deformation under various deflection angles and defect conditions. The reliability of the laboratory tests was verified through theoretical stress calculations under the non-deflection condition. The credibility of the laboratory test results was further enhanced by employing a numerical model and normalized parameters. Key findings reveal that stress distribution characteristics are jointly determined by the deflection mode and load. Co-directional deflection exhibits a more significant stress concentration effect; under identical load and angle conditions, it results in higher stress levels due to a superposition effect, whereas diagonal deflection shows a weakening effect. Joint deformation progresses through three distinct stages. The linear growth stage exhibits an initial linear strain–load relationship under stable deflection (load < 2 kN). The accelerated deformation stage is characterized by nonlinear strain growth with a slowing deformation rate (2–4 kN). The deformation deceleration stage finally shows a slow linear strain increment (load > 4 kN). Increasing load and deflection angle significantly amplify axial deformation, particularly revealing a “thick-in-the-middle, thin-at-the-sides” compression characteristic in the 45° vault zones. Furthermore, segment defects markedly exacerbate stress non-uniformity. Defect angles ≥ 60° substantially increase the frequency and amplitude of compressive stress in the vault, accelerate the decay of tensile stress at the bottom, and critically reduce structural stability. These new findings provide significant insights for deflection control and structural safety assessment in pipe jacking engineering. The experimental framework provides fundamental insights into construction operations in upper-soft and lower-hard strata tunneling. Full article

Modern automotive design has increasingly embraced plastics for bumper construction; however, it can lead to material degradation. To overcome these limitations, the automotive industry is turning to fiber–resin material, namely carbon–epoxy composites. Our research focuses on determining the effects of fiber orientation and angle alignment on the structural stress of the car bumper, examining the hybrid material (carbon–epoxy reinforced by CFRP) in static structural tests, and performing dynamic impact tests at various speeds, applying the Tsai–Wu criterion as a basic failure model. However, Tsai–Wu’s failure in numerical analysis highlights the limitation of not being able to experimentally distinguish between failure modes and their interaction coefficients. To address this issue, we employ ANSYS^® 2024 R1 with a Fortran program, which enables more accurate estimation of failure behavior, resulting in an average error of 13.19%. To identify research gaps, machine learning (ML) plays a vital role in predicting parameter values and assessing data normality using various algorithms. By combining ML and FEA simulations, the result shows strong data performance. Bridging from 2 mm mesh sizing of 50% carbon–epoxy woven/50% CFRP laminate in 6 mm thickness at 0° orientation shows the most distributed shear stresses and deformation, which converged toward stable values. For comprehensive research, total deformation was included in ML analysis as a second target to build a multivariate analysis. Overall, Random Forest (RF) is the best-performing model, indicating superior robustness for modeling shear stress and total deformation. Full article

A novel methodology is proposed for accelerating the calculation efficiency of the boundary element modeling of rolling contact. This methodology involves the implementation of an initial solution estimate. The method is to provide the initial estimate value by means of simplifying the method, which is used for the iterative calculation of the boundary element method to solve the normal and tangential contact problems. In the normal contact problem, the normal pressure and contact patch are provided as the initial values for the iterative calculation of the boundary element method. In the tangential contact problem, the initial values for tangential stress and adhesion-slip distribution are provided. A first novel aspect is breaking the initial iteration setting of the traditional BEM, which can significantly reduce the iterations. A second novelty is that a method for determining the potential contact area is proposed to ensure the correctness of boundary element modeling without increasing the computational cost. In the following section, an analysis is conducted to ascertain the impact of the initial solution estimate method on the efficacy of boundary element modeling. The result is that efficiency increased by 69.1% of normal contact calculations, with the initial contact patch exerting the most significant influence. The efficiency of the process under investigation increased by 56.9%, and the most pronounced effect is the distribution of adhesion-slip. Full article

In the field of tunnel engineering, it is often difficult to avoid crossing active faults. During an earthquake, tunnels across faults are highly vulnerable to damage. Therefore, conducting research on their mechanical responses and failure mechanisms is of great significance. This paper takes Xianglushan Tunnel as a research example and uses finite element software to carry out numerical simulation of the tunnel under the action of the left-lateral normal fault activity. Moreover, the effectiveness of this model is verified using the actual measurement data of the damaged tunnels during the Kumamoto earthquake. By comparing the damage conditions and stress states of the tunnel under the action of left-lateral normal faults and strike-slip faults, and conducting a systematic and refined study on relevant fault parameters, the following research results are obtained: First, compared with oblique-slip faults, strike-slip faults cause more severe damage to the tunnel; second, tunnel damage is mainly concentrated in the area where the fault slip surface is located; third, an increase in fault displacement can significantly exacerbate structural damage and is the main factor leading to tunnel failure; fourth, the dip angle of the fault affects the stress distribution of the tunnel. As the dip angle increases, the damaged area gradually shrinks; fifth, the change in the width of the fault fracture zone will alter the failure mode of the tunnel. Reasonably choosing to cross a wider fault can reduce the structural damage. This research provides theoretical support and practical reference for the seismic design of tunnels across faults. Full article