Search Results (25,884)

This study introduces a theoretical and computational framework for modeling acoustic wave propagation in defective concrete, with applications to non-destructive testing and structural health monitoring. The formulation is based on a coupled system of evolutionary hyperbolic equations, where internal defects are explicitly represented as localized energetic sources or sinks. A key contribution is the definition of acoercivity coefficient, which quantifies the energetic effect of defects and enables their classification as stabilizing, neutral, or dissipative. The model establishes a rigorous relationship between defect morphology, spatial distribution, and the global energetic stability of the material. Numerical simulations performed with an explicit finite-difference time-domain scheme confirm the theoretical predictions: the normalized total energy remains above $95\%$ for stabilizing defects (${\mu }_i>0$), decreases by about $10\%$ for quasi-neutral cases (${\mu }_i\approx 0$), and drops below $50\%$ within $200\mathsf{\mu }\mathrm{s}$ for dissipative defects (${\mu }_i<0$). The proposed approach reproduces the attenuation and phase behavior of classical Biot-type and Kelvin–Voigt models with deviations below $5\%$ while providing a richer energetic interpretation of local defect dynamics. Although primarily theoretical, this study establishes a physically consistent and quantitatively validated framework that supports the development of predictive ultrasonic indicators for the energetic classification of defects in concrete structures. Full article

The fracture behavior of the Al₄Cu₉ intermetallic compound at the interface of impact-welded Cu/Al joints remains insufficiently explored through integrated multiscale modeling and experimental validation. In this study, molecular dynamic (MD) simulations, finite element (FE) analysis implemented in ABAQUS (version 2020) and a cohesive zone model (CZM) were combined with optical microscopy (OM) and scanning electron microscopy (SEM) observations of the interface and crack initiation zones in impact-welded Cu/Al specimens to investigate crack propagation mechanisms under different defect configurations. The experimental specimens consisted of 1060 aluminum (Al) and oxygen-free high-conductivity (OFHC) copper, fabricated via impact welding and subsequently annealed at 250 °C for 100 h. The interfacial morphology and crack initiation features obtained from OM and SEM provided direct validation for the traction–separation (T-S) parameters extracted from MD and mapped into the FE model. The results indicate that composite defects (blunt crack + void) cause a significantly greater reduction in fracture energy and stress intensity factor than single defects and that defect effects outweigh temperature effects within the range of 200–500 K. The experimentally observed crack initiation locations were in strong agreement with simulation predictions. This integrated simulation–experiment approach not only elucidates the multiscale fracture mechanisms of the Al₄Cu₉ interface but also provides a physically validated basis for the reliability assessment and optimization of aerospace Cu/Al welded structures. Full article

The rapid increase in global human activities and urban surface modifications has exacerbated the urban heat island effect, prompting growing scholarly efforts to adopt various measures for mitigating heat islands worldwide. This paper reviews existing literature on rooftop mitigation of UHI, summarizes specific existing rooftop mitigation measures, and examines the comparative effectiveness of various rooftop mitigation strategies in reducing urban heat islands. Findings indicate that cool roofs are the most effective rooftop measure for mitigating UHI, followed by green roofs and photovoltaic roofs. Simultaneously, the cooling effectiveness of rooftop mitigation strategies is influenced by their inherent characteristics (reflectivity, coverage, orientation, etc.), geographical and climatic features (latitude, humidity levels, temperature extremes, diurnal temperature variation, etc.), and urban morphology (building density, height, shape index, etc.). The research status summarized herein provides valuable insights for policy formulation and guides future studies, thereby promoting more innovative designs for sustainable urban roofs to mitigate UHI. Full article

Mancozeb is a broad-spectrum fungicide used extensively in agriculture to protect crops against a wide range of plant diseases. Although its capacity to induce oxidative stress is well documented, the cytotoxic effects of mancozeb on red blood cells (RBCs) remain poorly characterized. The present study aimed to investigate the cytotoxic effects of mancozeb on isolated RBCs, with particular focus on oxidative stress-induced cellular and molecular alterations. Human RBCs were exposed to mancozeb (0.5–100 µM) for 24 h. No hemolytic activity was observed across the tested concentrations. However, 10 and 100 µM mancozeb induced a significant increase in intracellular reactive oxygen species (ROS), leading to lipid and protein oxidation and impaired Na⁺/K⁺-ATPase and anion exchanger 1 (AE1) function. These changes resulted in altered RBC morphology, reduced deformability, and increased methemoglobin levels. Alterations in glycophorin A distribution, anion exchanger 1 (AE1) clustering and phosphorylation, and α/β-spectrin and band 4.1 re-arrangement indicated disrupted membrane–cytoskeleton interactions. A release of extracellular vesicles (EVs) positive for glycophorin A and annexin-V was also observed, consistent with plasma membrane remodeling. Despite increased intracellular calcium, eryptosis remained minimal, possibly due to activation of protective estrogen receptor (ER)-mediated pathways involving ERK1/2 and AKT signaling. Activation of the cellular antioxidant system and the glutathione redox system (GSH/GSSG) occurred, with catalase (CAT) playing a predominant role, while superoxide dismutase (SOD) activity remained largely unchanged. These findings offer mechanistic insights regarding the potential health impact of oxidative stress induced by pesticide exposure. Full article

Lutein is one of carotenoids in the human brain that is consistently associated with all cognitive performance indicators, and its levels are closely linked to age-related cognitive decline. However, lutein application is limited by its poor stability and low bioaccessibility. In this study, a lutein-loaded delivery system was developed to enhance stability and achieve brain-targeting effects. Using high-speed shear and ethanol hydration methods, PEGylated lutein liposomes with lactoferrin (Lf-LLips) were constructed and characterized. The morphology was observed using TEM and AFM. Particle sizes and lutein retention rates were evaluated under different temperatures (4 °C, 25 ± 2 °C, 50 °C), light (diffusion light, DL; light shielding, LS), and storage durations at 28 d. Compared with free lutein, the in vitro release behavior and permeability across the blood–brain barrier of the systems were investigated. Lf-LLips exhibited a particle size of 186.63 ± 2.04 nm and a potential of −30.53 ± 1.65 mV, and the lutein encapsulation efficiency was 83.11 ± 1.67%. When stored under LS, the particle size of Lf-LLips remained under 190 nm at 4 °C for 28 days, and the retention rate of lutein exceeded 80%. The release curve of Lf-LLips in vitro over 72 h followed the Weibull model. Furthermore, the permeability across the blood–brain barrier model within 12 h was 22.73 ± 1.42%. These results demonstrate that Lf-LLips significantly improve the stability of lutein and exhibit sustained-release properties along with brain-targeting efficiency. The findings demonstrate the promising future of lutein for applications in brain health enhancement. Full article

Elevated exposure to manganese (Mn) has been linked to a broad spectrum of neurological disorders, including motor dysfunction. Neuroinflammation with excessively activated astrocytes plays a critical role in the pathogenesis and progression of neurodegenerative diseases. Astrocyte-mediated neuroinflammation plays a dual role due to distinct astrocyte phenotypes, including deleterious A1 and neuroprotective A2. Our previous studies have confirmed that Mn induces activation of astrocytes in the central nervous system, and endoplasmic reticulum (ER) stress has been verified to regulate A1 activation; however, the molecular mechanisms underlying Mn-induced neurotoxicity remain incompletely understood. We establish in vivo and in vitro Mn exposure models and observed that Mn induced A1 activation of astrocytes in both models, with upregulation of A1-specific markers. Sub-cellular morphological analysis showed Mn-induced ER stress in A1-type astrocytes. We found that EIF2α-PERK signaling pathways are activated in astrocytes and drive ER stress and mitochondrial impairment. Suppression of astrocytic PERK, using either ISRIB or GSK2606414, alleviates Mn-induced ER stress and A1 activation, which in turn mitigates the motor deficits induced by Mn exposure. These findings reveal that inhibition of PERK can ameliorate Mn-induced neurotoxicity by suppressing astrocyte activation and preserving organelle homeostasis, offering a potential therapeutic strategy to mitigate the harmful effects of Mn toxicity. Full article

Longya Lily (Lilium brownii var. viridulum) bulb rot, a devastating soil-borne disease caused by Fusarium oxysporum f. sp. lilii (Fol L1-1), severely compromises yield and quality of this economically significant crop. In this study, strain R12 was isolated from the rhizosphere soil of asymptomatic Longya lily plants and identified as Bacillus velezensis. The strain significantly disrupted the spore germination and hyphal morphology of Fol L1-1. In pot experiments, R12 not only effectively suppressed disease development but also promoted plant growth, a trait potentially linked to its indole-3-acetic acid (IAA) production capacity. Genomic analysis revealed a 4,015,523 bp circular chromosome (46.42% GC content) harboring gene clusters for the synthesis of diverse secondary metabolites, including surfactin, fengycin, difficidin, and bacillibactin. These findings highlight the potential of B. velezensis R12 as a biocontrol agent and provide insights into its mechanisms for suppressing phytopathogens and promoting plant growth. Full article

This study aimed to investigate the effects of dietary supplementation with TBZC on the growth performance, diarrhea incidence, antioxidant ability, immune function, and intestinal health of weaned piglets. A total of 120 weaned piglets were randomly allocated to one of three dietary treatments with six replicate pens and eight piglets per pen: CON—a basal diet; ZnO—a basal diet with 1500 mg Zn/kg from ZnO; and TBZC—a basal diet with 680 mg Zn/kg from TBZC. Following a 42-day period of consuming the zinc-enriched diet, the piglets were switched to a basal diet for the remaining 28 days of the trial. The dietary TBZC increased the average daily feed intake of weaned piglets (ADFI) from days 1 to 14 and the average daily growth (ADG) from days 43 to 70 compared with the ZnO group (p < 0.05). The supplementation with TBZC decreased the acid-binding capacity compared with the ZnO group (p < 0.05). Moreover, dietary TBZC decreased the MDA concentration and increased the GSH-Px concentration on day 14 and increased the SOD activity on day 28 and the GSH-Px concentration on day 70 compared with the ZnO group (p < 0.05). Compared with the ZnO group, the dietary TBAC supplementation increased (p < 0.05) the relative abundance of cecal Lactobacillus spp. and Blautia spp., while decreasing Blautia spp. in the colonic contents; increased (p < 0.05) the relative abundance of Prevotella spp. and Clostridium_sensu_stricto_1; and reduced (p < 0.05) Streptococcus spp. Therefore, replacing 1500 mg/kg of ZnO with 680 mg/kg of TBZC improves growth performance and antioxidant capacity and regulates gut microbes in weaned piglets. Full article

Apple scab poses a significant threat to wild apple orchards in the Ili region of Xinjiang, yet the pathogen responsible and its disease dynamics remain poorly understood. This study aimed to identify the causal agent of apple scab in wild apples and elucidate its disease development pattern to support effective monitoring and control strategies. Field surveys were conducted regularly from 2023 to 2025 in fixed plots and sample trees of Malus sieversii. A total of 29 isolates were obtained from diseased fruits collected in Xinyuan and Huocheng counties using tissue isolation and single-spore purification. Pathogenicity was confirmed via Koch’s postulates, and the pathogen was identified based on morphological and molecular characteristics. Scab symptoms first appeared on leaves in late April (during leaf expansion, disease index 0.34) and on fruits in early June (during fruit enlargement, disease index 0.57). The disease index peaked in late August (47.24 on leaves; 22.51 on fruits), followed by fruit drop at month-end and leaf abscission in late September. The pathogen overwintered mainly in remaining or fallen diseased leaves (isolation rate 17.71%), serving as the primary source of initial infection in the following growing season. The pathogen causing apple scab in Xinjiang wild apple orchards was identified as Venturia inaequalis. Overwintered infected leaves were confirmed as the key primary inoculum source. These findings clarify the taxonomic identity of the pathogen and its epidemic pattern, providing a theoretical basis for disease management. Full article

As an eco-friendly flame-retardant additive, magnesium hydroxide (MH) is widely employed in low-smoking, halogen-free polymer materials due to its environmentally benign nature. In order to enhance flame retardancy performance, the modified MH was modified with tetrakis(hydroxymethyl)phosphonium sulfate (THPS) by a one-pot hydrothermal method. The resulting morphology was characterized using scanning electron microscopy (SEM), and it shows the dispersion of nanometer particles and almost no aggregation. The X-ray photoelectron spectroscopy (XPS) along with Raman spectroscopy show that the THPS is connected with the Mg(OH)₂ by chemical bond. The sample was incorporated into ethylene–vinyl acetate (EVA) to evaluate the flame retardancy was assessed via limiting oxygen index (LOI) and vertical burning tests (UL-94). The results show that THPS modified MH effectively enhanced the flame retardancy, achieving a V-0 rating and an LOI value of 31.3%. In addition, the composites retain good mechanical integrity. The thermal analysis with TGA and DTG shows the formation of the MgO decomposition product, along with water vapor and phosphorus-containing radicals released by modified MH in the combustion process, forming a strong flame-retardant protective layer. In addition, the maximum smoke density of EVA/MHP-3 composite was 155.4, lower than 411.3 for EVA/MH, with a 62.2% reduction in total smoke production. The result shows that THPS is effective for improving the flame-retardant efficiency of inorganic metal hydroxide in polymer composites. Full article

Cracks in laser-cladded coatings represent a critical challenge that severely limits their industrial deployment. In this study, high-frequency pulsed direct current-assisted electrically assisted heat treatment (EAHT) was applied to repair cracks in laser-cladded Ni60/WC coatings deposited on 45# medium carbon steel. The influence of current density and treatment duration on crack arrest and healing behavior was systematically investigated. Dye penetrant testing and scanning electron microscopy (SEM) were employed to characterize the morphology and evolution of cracks before and after EAHT, while hardness, fracture toughness, and wear resistance tests were conducted to evaluate the mechanical properties. The results revealed that the crack repair process proceeds through three distinct stages: internal filling, nucleation and growth of healing points, and complete crack closure. The combined effects of Joule heating and current crowding induced by EAHT significantly facilitated progressive crack healing from the bottom upward. Optimal crack arrest and healing were achieved at a current density of 6.25 A/mm², resulting in a maximum fracture toughness of 10.74 MPa·m^1/2 and a transition of the wear mechanism from spalling to abrasive wear. This study demonstrates that EAHT promotes selective crack-tip heating and microstructural regulation through thermo-electro-mechanical coupling, thereby markedly enhancing the comprehensive performance of Ni-based WC coatings. Full article

Corylus avellana L. is a rare and endangered species in Kazakhstan, included in the national Red Book. The results of morphological and genetic characterization of the sole known natural population of C. avellana in the Western Kazakhstan region are presented in this study. Sixty wild accessions were evaluated based on tree and leaf morphological traits using standard descriptors in accordance with Bioversity International guidelines. Genetic diversity was assessed using ten nuclear simple sequence repeat (SSR) markers. A total of 120 alleles were detected across the nuclear loci, with the number of alleles per locus ranging from 9 to 16 and an average of 12. The mean effective number of alleles (Ne) per locus was 3.862. A high level of intraspecific polymorphism was observed, with an average observed heterozygosity (Ho) of 0.70. The population showed considerable genetic diversity, as highlighted by a mean Shannon’s diversity index of 1.526. STRUCTURE, PCoA, and phylogenetic analyses confirmed strong differentiation between the wild Kazakh population and the cultivated hazelnut germplasm. Due to the lack of viable seeds, in vitro conservation was initiated using vegetative shoots. A two-step disinfection protocol, involving Plant Preservative Mixture and mercuric chloride, significantly improved explant survival, enabling successful establishment of an aseptic in vitro collection. These findings highlight the urgent need for targeted conservation strategies and show the potential of biotechnological approaches for safeguarding Kazakhstan’s only natural C. avellana population. Full article

The development of stable and efficient nanolubricants remains one of the main challenges in tribology due to particle agglomeration, poor long-term stability, and inconsistent frictional behavior under boundary lubrication. This study investigates the tribological performance of SAE 10W-40 engine oil enhanced with titanium dioxide (TiO₂) nanoparticles subjected to thermal treatments. TiO₂ powders (Degussa P25, ~30 nm) were calcined at 450 °C, 550 °C, 650 °C, and 750 °C, and incorporated into the base oil at a constant concentration of 0.05 wt%. Tribological tests were conducted using a four-ball tribometer under ASTM D4172 conditions (396 N, 1200 rpm, 30 min) at both ambient (23 °C) and elevated (75 °C) temperatures. The coefficient of friction (COF) and wear scar area (WSA) were measured, while the surface morphology was analyzed via 3D optical profilometry, SEM, and EDS. The results indicate that TiO₂ nanoparticles thermally treated at 550 °C offered the best tribological behavior, exhibiting the lowest COF and smallest WSA at both test temperatures. The improved performance is attributed to optimized crystalline structure and enhanced dispersion stability after calcination. Although no Ti-based tribofilm was detected, smoother wear scars suggest physical surface protection mechanisms, such as rolling and asperity smoothing. These findings highlight the critical influence of thermal treatment on nanoparticle effectiveness and demonstrate the potential of optimized nanoadditized lubricants for advanced friction and wear reduction under boundary lubrication conditions, providing practical guidance for developing next generation nanolubricants with improved durability and efficiency under boundary lubrication conditions. Full article

To address challenges such as temperature rise, operational instability, and premature failure in rolling bearings caused by retainer friction, this study designed and developed a high-performance polyimide (PI)-based composite self-lubricating retainer to enable “ultra-stable” bearing operation. Both solid and oil-porous self-lubricating retainers were fabricated through material composition and structural design. Systematic tests under controlled load and speed conditions were conducted to compare their temperature rise behavior and wear morphology. The results demonstrated that the temperature rise in the YSU-PI1 bearing with a solid retainer decreased by approximately 57% compared to a conventional bearing. The YSU-PA2 bearing with an oil-porous retainer exhibited a further improvement in thermal performance. Notably, under high-speed conditions, the equilibrium temperature of the YSU-PA2 bearing was lower than that under low-speed conditions, confirming a centrifugal-force-driven self-regulating oil-supply mechanism. Wear surface analysis revealed that the porous structure promoted the formation of a continuous and uniform transfer film, effectively mitigating wear and pitting. This study successfully integrates “material–structure–function” innovation. The oil-porous PI-based composite retainer transforms centrifugal force—typically considered detrimental—into a beneficial lubrication mechanism, effectively suppressing temperature rise and enabling “ultra-stable operation”. These findings provide crucial theoretical and technical support for developing bearings for high-end equipment. Full article

One-dimensional (1D) nanowires represent a critical class of nanomaterials with extensive applications in biosensing, biomedicine, bioelectronics, and energy harvesting. In materials science, accurately extracting their morphological and structural features is essential for effective image segmentation. However, 1D nanowires frequently appear in dispersed or entangled configurations, often with blurred backgrounds and indistinct boundaries, which significantly complicates the segmentation process. Traditional threshold-based methods struggle to segment these structurally complex nanowires with high precision. To address this challenge, we propose a wavelet-based Bilateral Segmentation Network named WaveBiSeNet, to which a Dual Wavelet Convolution Module (DWCM) and a Flexible Upsampling Module (FUM) are introduced to enhance feature representation and improve segmentation accuracy. In this study, we benchmarked WaveBiSeNet against ten segmentation models on a peptide nanowire image dataset. Experimental results demonstrate that WaveBiSeNet achieves, mIoU of 77.59%, an accuracy of 89.95%, an F1 score of 87.22%, and a Kappa coefficient of 74.13%, respectively. Compared to other advanced models, our proposed model achieves better segmentation performance. These findings demonstrate that WaveBiSeNet is an end-to-end deep segmentation network capable of accurately analyzing complex 1D nanowire structures. Full article