Search Results (42,433)

To investigate the aging behavior of high-temperature-vulcanized silicone rubber (HTV-SiR) used in composite insulator sheds under coupled electrical, thermal, humidity, and mechanical stresses, accelerated aging tests were conducted to emulate the service conditions of ±800 kV ultra-high-voltage direct current (UHVDC) systems in Guangzhou, China. The physicochemical, mechanical, and electrical properties of the specimens were systematically characterized. The results show simultaneous degradation of both electrical and mechanical performance. In particular, the tensile strength exhibits a significant monotonic decrease and drops to 49.52% of its initial value under the most severe condition (0.5 kV·mm⁻¹ and 5% tensile strain) after 75 days. In contrast, the DC breakdown strength shows a non-monotonic “rise-then-fall” trend and decreases more markedly with increasing tensile strain. To address the one-shot and destructive nature of tensile testing and the associated statistical uncertainties, a lifetime prediction framework was developed by integrating a generalized Eyring acceleration relation with a stochastic degradation process. Under representative service conditions of 0.09 kV·mm⁻¹ and 0.2% tensile strain, the predicted lifetimes corresponding to failure probabilities of 10%, 75%, and 90% are 1.77, 9.08, and 17.90 years, respectively. The applicability of the model is supported by field-aged specimens. These findings provide a mechanistically grounded and reliability-oriented basis for condition assessment, lifetime-margin evaluation, material screening, and maintenance planning of UHVDC composite insulators operating in hot–humid environments. Full article

This study investigated the adaptive mechanisms of silver pomfret in response to chronic low-temperature stress, focusing on the tissue-specific expression patterns of the key lipid metabolism gene scd1 and its central role in regulating hepatic apoptosis. A gradual cooling experiment (from 18 °C to 6 °C) was conducted to analyze the spatiotemporal expression profiles of ten lipid metabolism-related genes across six tissues. The results revealed that the most pronounced changes were observed in the heart, liver, and gills. The liver and heart rapidly activated genes involved in lipid breakdown and utilization from 16 to 12 °C for immediate energy supply, while gill tissue upregulated the pi3k/p450/srebp/scd1 pathway at 10 °C to remodel membrane lipids against sustained stress. Further in vitro hepatocyte experiments demonstrated that scd1 expression directly regulated cell survival and apoptosis under low temperatures. Knockdown of scd1 significantly promoted apoptosis, whereas its overexpression effectively suppressed it. Moreover, scd1 expression was intricately modulated by its upstream regulators srebp (positive regulation) and pparγ (showing potential negative feedback at specific temperatures). This study systematically elucidates the pivotal role of scd1-mediated lipid metabolic reprogramming in the cold adaptation of silver pomfret, providing a crucial theoretical foundation for deciphering the molecular mechanisms of cold tolerance and for breeding cold-resistant strains. Full article

Environmental, genetic, immunological and metabolic factors are involved in renal cell carcinoma development. Clear cell renal carcinoma (ccRCC) is the most frequent renal cancer, with a complex metabolic physiopathology. The present study focuses on the characterization of chemical changes in glutathione redox homeostasis induced by oxidative damage and their relevance to ccRCC. We developed a prospective, case–control study that included 92 subjects diagnosed with ccRCC by histopathological exam and 40 healthy subjects. In each subject, we evaluated the chemical changes in glutathione redox homeostasis, antioxidative capacity, nitrosative stress, carbonyl stress, inflammation (IL-12 family members, albumin), angiogenesis factors and apoptosis. Compared to the control, in ccRCC subjects, we detected high levels of oxidative/electrophile stress, of hypoxia, and of inflammatory- and angiogenesis-related factors and low levels of anti-inflammatory-, anti-oxidative- and apoptosis-related factors. In ccRCC, positive correlations between glutathione redox homeostasis members expression and electrophile metabolites levels, respectively, angiogenesis markers and inflammatory parameters detected. Negative relations with anti-inflammatory and antioxidant markers were assessed. Glutathione redox homeostasis was altered in ccRCC, functioning as an active redox mechanism, with an essential role in the development and progression of ccRCC. Full article

Diabetes mellitus affects an estimated 589 million adults globally, and cutaneous manifestations occur in up to 70% of affected individuals during the course of the disease. The objective of this narrative review is to examine the intersection of diabetes mellitus, skin aging, cosmetic dermatologic procedures, and regenerative therapies, with an emphasis on evidence-based best practices and clinical considerations. While the impaired wound healing associated with diabetes has been extensively studied, the aesthetic implications of diabetic skin disease remain comparatively underexplored. Individuals with diabetes frequently exhibit features of accelerated cutaneous aging, including premature wrinkling, dyschromia, xerosis, alopecia, and other cosmetically significant dermatoses that may negatively impact quality of life. In parallel, the demand for aesthetic dermatologic procedures among patients with diabetes has increased substantially; however, evidence-based recommendations guiding the safe and effective use of cosmetic interventions in this population remain limited. Diabetic skin demonstrates accelerated biological aging driven by complex pathophysiological mechanisms, including the accumulation of advanced glycation end products, chronic low-grade inflammation, oxidative stress, microvascular dysfunction, and neuropathy. These processes partially overlap with chronological aging and photoaging but are mechanistically distinct and may influence tissue repair, inflammatory responses, and the safety profile of commonly performed aesthetic procedures such as chemical peels, laser resurfacing, dermal fillers, neuromodulators, and microneedling. Emerging regenerative approaches, including platelet-rich plasma, platelet lysate, and mesenchymal stromal cell-derived products such as exosomes and secretomes, have attracted increasing attention as biologically targeted strategies for cutaneous rejuvenation. Nevertheless, clinical evidence specifically addressing aesthetic interventions in diabetic populations remains limited. A diabetes-informed approach to aesthetic dermatology that considers metabolic status, procedure selection, and post-procedural monitoring is therefore essential to optimize safety and therapeutic outcomes. Full article

Periodic lattice materials exhibit tunable mechanical properties, yet the impact of non-cylindrical, non-circular strut cross-sections on crashworthiness remains largely unexplored. This study extends the concept of shape transformers—dimensionless ratios representing the area and second moment of area of a strut cross-section relative to its enclosing envelope—to two canonical lattice topologies: the octet and rhombic dodecahedron topologies (stretching-dominated and bending-dominated, respectively). Eleven distinct cross-sectional shapes (solid and hollow circular, diamond, and square) were systematically varied under constant area and constant envelope conditions to isolate microscale geometric effects on macroscopic impact response. Results demonstrate that adjusting Ψ_i alone can enhance specific energy absorption by up to 62% in bending-dominated lattices (compared to 18% in stretching-dominated lattices). Furthermore, the influence of geometric efficiency (λ = Ψ_i/Ψ_a) on plateau stress and energy absorption trends across topologies has been quantified. These findings establish shape transformers as significant design parameters for crashworthy lattice materials, and design charts are presented to facilitate the development of additive-manufactured cellular structures aimed at optimized energy absorption performance. Full article

Introduction: Asthma is one of the most common chronic diseases in childhood and represents a major global public health concern due to its high prevalence, healthcare burden, and impact on quality of life. Pediatric asthma is characterized by clinical and biological heterogeneity, reflected in variable airflow limitations and distinct inflammatory endotypes. Conventional diagnostic tools do not fully capture the metabolic mechanisms underlying lung function impairment and disease variability. Aim: This narrative review aims to synthesize evidence published linking metabolomic and breathomic signatures to lung function parameters in children with asthma. Methods: We searched PubMed, Scopus, and Google Scholar using predefined keywords including pediatric asthma, metabolomics, breathomics, volatile organic compounds, exhaled breath condensate, and lung function. The search covered publications from January 2015 to January 2026. Earlier studies were included when necessary for the conceptual or methodological context. We included human studies evaluating metabolomic or breathomic profiles in children (≤18 years) and reporting associations with lung function, severity, endotypes, or exacerbations. Duplicate records, adult-only studies, animal models, non-English publications, and conference abstracts without full data were excluded. Results: Alterations in lipid and sphingolipid metabolism, oxidative stress pathways, and purine metabolism were associated with airflow limitation and reduced FEV1. Breathomic analyses revealed associations between volatile profiles, small airway dysfunction, and inflammatory patterns. However, findings remain heterogeneous across biological matrices and analytical platforms. Conclusions: Metabolomic and breathomic profiling may complement conventional lung function assessment by providing additional mechanistic insight into pediatric asthma heterogeneity. Standardized methodologies, longitudinal validation, and integration within multi-omics approaches are required before routine clinical implementation. Full article

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine–metabolic disorder characterized by endocrine disruption, insulin resistance, hyperandrogenism, and chronic low-grade inflammation, in which oxidative stress has been proposed as a mechanistic link between metabolic and reproductive dysfunction. This narrative review summarizes current evidence on redox-related mechanisms and evaluates dietary and supplemental antioxidants in PCOS. Clinical trials, systematic reviews, and mechanistic studies were examined to assess antioxidant classification, signaling pathways, and outcomes related to metabolic, endocrine, reproductive, and oxidative stress parameters. Antioxidant interventions frequently modify circulating redox biomarkers and may improve selected metabolic indices; however, consistent effects on hormonal regulation, ovulation, and long-term clinical outcomes remain limited and heterogeneous. Differences in study design, antioxidant formulation and dosage, baseline metabolic status, and outcome selection complicate interpretation, while emerging evidence suggests modulation by lifestyle factors and gut microbiota-related mechanisms. Overall, antioxidants appear to act primarily through modulation of endogenous redox regulation rather than direct reactive oxygen species scavenging and are best considered adjuncts to lifestyle-based management. Further phenotype-informed and longitudinal studies using clinically relevant endpoints are required to clarify therapeutic relevance in PCOS. Full article

To overcome the low strength of conventional polytetrafluoroethylene/aluminum (PTFE/Al) reactive materials and the insufficient reaction efficiency of aluminum, this study introduces highly reactive aluminum–cerium alloys (Al-Ce-1#, -2#, and -3#, with Ce contents of 30, 50, and 70%, respectively; the primary phase in Al-Ce-3# is Al₂Ce) with a multiscale structural design (comprising both micron-sized and nano-sized particles) into an ammonium perchlorate (AP) matrix. Al/AP reactive materials and Al-Ce/AP reactive materials with varying Ce contents were prepared. The thermal decomposition characteristics, dynamic mechanical properties, and impact ignition behavior were systematically investigated using differential scanning calorimetry (DSC) and split Hopkinson pressure bar (SHPB) experiments. The results demonstrate that the addition of Al₂Ce significantly alters the thermal decomposition process of AP, substantially lowering its decomposition temperature (by approximately 69 °C) and promoting concentrated exothermic decomposition. SHPB tests reveal that Al₂Ce/AP composites exhibit higher dynamic yield strength and flow stress than the Al/AP, accumulating faster strain energy density under impact loading, which indicates a more violent fragmentation failure mode. This enhanced mechanical failure behavior, which provides highly reactive interfaces and promotes hotspot formation, synergizes with the catalytic effect of Al₂Ce on AP decomposition. Together, these mechanisms jointly improve the impact ignition sensitivity of the material, significantly lowering its ignition threshold and shortening its combustion duration. This study confirms that Al₂Ce/AP is a novel reactive material combining excellent dynamic mechanical properties with outstanding impact reactivity, providing theoretical and technical support for the application of highly reactive rare-earth aluminum alloys in aluminum-based reactive materials. Full article

Ceramides, sphingolipids produced from fatty acids linked to sphingosine and an amide, are structural elements of cellular membranes and lipoproteins. These molecules also retain biological effects in key cellular pathways such as oxidative stress and inflammation, apoptosis, and fibrosis, with a role in the onset and development of many pathophysiological conditions, including obesity, diabetes, and insulin resistance. Increasing evidence suggests that different nutrients and dietary patterns may affect ceramide levels, both negatively (e.g., fructose and the Western diet), whereas others improve the ceramide profile (e.g., ω-3 PUFAs, resveratrol, vitamin D, and the Mediterranean and the Nordic diets). Thus, ceramide nutritional modulation could represent a simple, additive, and reliable tool to improve metabolic health. This review focused on the role of ceramides in the pathophysiology of diabetes and obesity, as well as their pathogenetic mechanisms of action. Ceramides are increasingly recognized as “dynamic metabolic interfaces” linking nutrition and disease. This review aims to address a critical gap by synthesizing recent evidence on how dietary interventions, in addition to pharmacological approaches, can specifically target the enzymatic pathways involved in ceramide synthesis to enhance metabolic health. Thus, this review offers a concentrated analysis of the response of specific ceramide species, such as Cer16:0 and Cer18:0, to distinct dietary factors. Additionally, it incorporates emerging evidence on the role of gut microbiota in the biotransformation of sphingolipids, thereby adding a contemporary dimension to the established nutritional perspective. Full article

Trees in arid mountainous forests adapt to seasonal water variability through dynamic eco-physiological adjustments. This study investigated the spatiotemporal dynamics and environmental drivers of such adaptations in Picea schrenkiana Fisch. et Mey, a keystone conifer in China’s Tianshan Mountains. We monitored key indicators—including osmoregulatory substances, antioxidant enzyme activities, and stoichiometric traits—across three regions (eastern, central, western) and three seasons (spring, summer, autumn) during the 2023 growing season. The results revealed significant seasonal shifts in all the measured traits (p < 0.05). Spring was characterized by high carbon allocation toward soluble sugars and starch, supporting growth; summer triggered elevated antioxidant enzyme activities to mitigate oxidative stress; and autumn favored nitrogen accumulation and proline synthesis, indicating preparatory storage for winter. Soil factors were primarily positively associated with antioxidant enzyme activity (path coefficient = 0.51; p < 0.001), whereas microenvironmental factors were more complex and often negatively correlated. The partial least squares path model confirmed that osmoregulatory substances centrally link stoichiometric adjustments with antioxidant defense, revealing an integrated physiological strategy. These findings elucidate the mechanism underlying the resilience of P. schrenkiana in arid highlands and provide a framework for its conservation under environmental change. Full article

Cervical cancer (CC) is a complex, multistep process involving various viral, molecular, cellular, endogenous, and environmental events that transform normal cervical epithelium into a malignant tumor through a cascade of events. The contribution of high-risk human papillomavirus (HPV) to cancer is significant but involves many additional mechanisms such as oxidative stress (OS), arrested apoptosis of non-functional intraepithelial neoplastic cells, senescence-associated secretory phenotype (SASP), and the final epithelial–mesenchymal transition (EMT) of cervical epithelial neoplasia (CIN) cells. While high-risk HPV oncoproteins E6 and E7 are widely recognized as the primary triggers of CC, the critical role of E6 in degrading the p53 regulatory protein, thereby inhibiting the apoptosis of reactive oxygen species (ROS)-damaged neoplastic cells, is frequently underappreciated in the gynecological literature. Arrested apoptosis of non-functional neoplastic intraepithelial cells is a key event in cervical carcinogenesis and the biological basis of CIN progression via SASP senescence and ultimately EMT. While recent reviews touched upon each of the reviewed aspects, this review aims to provide a general understanding of all links in this complex molecular-biological chain, from HPV infection, oxidative stress, arrested apoptosis, SASP, and EMT. Beyond providing an encompassing primer for clinical researchers, we additionally review potential oxidative stress-related markers for shifting the classic diagnostic and therapeutic paradigms of CIN and cervical cancer. Full article

This study developed poly(lactic acid) (PLA) biocomposites reinforced with pine wood flour (10, 20, and 30 wt%) to achieve the interphase through chemical modification. Specifically, the wood flour was treated with poly(propylene glycol) toluene 2,4-diisocyanate terminated (PEGTDI), while 1 wt% poly(lactic acid)-g-maleic anhydride (PLA-g-MA) was integrated as a reactive compatibilizer during extrusion and thermocompression. Fourier-transform infrared spectroscopy (FTIR) analysis corroborated the occurrence of urethane formation and ester/anhydride linkages, as substantiated by the presence of characteristic bands indicative of surface carbamation at 1645 and 1726 cm⁻¹. Thermal analysis revealed that both the pine wood flour and coupling agents promoted PLA crystallization; however, thermogravimetric analysis (TGA) indicated a decrease in thermal stability for functionalized composites, suggesting a trade-off between enhanced interfacial interaction and heat resistance. Mechanical testing demonstrated a significant reinforcement effect, with the Young’s modulus increasing by up to 22% in untreated composites. The coupling agents effectively optimized stress transfer at low fiber loadings (10 wt%), while flexural modulus improvements were predominant at higher loadings (20–30 wt%) regardless of treatment. These findings underscore the criticality of surface modification and compatibilizer selection for tailoring the structural and thermo-mechanical properties of PLA-based biocomposites, thereby providing a pathway for optimized performance in structural applications. Full article

This study collected 155 sets of test data for granite residual soils from the Fujian–Guangdong region and applied the chi-square test to analyze the distributions of eight common physical and mechanical parameters. Drained triaxial tests were then simulated using the Unified Hardening (UH) model, and a Sobol global sensitivity analysis of model parameters was conducted based on the distributions of soil properties. The results show that natural density and cohesion approximately follow Weibull distributions; void ratio, liquid limit and plastic limit follow lognormal distributions; water content and internal friction angle follow normal distributions; and plasticity index follows a Gumbel distribution. The Sobol analysis indicates that the critical state deviatoric stress mainly depends on the critical state stress ratio (M), the critical state volumetric strain is jointly controlled by M and the slope of the normal compression line (λ). The overall evolution of deviatoric stress mainly depends on M, and the overall evolution of volumetric strain mainly depends on λ, whereas Poisson’s ratio (ν) has little influence on the soil stress–strain response. These findings provide references for parameter selection and numerical simulation of granite residual soils in the Fujian–Guangdong region. Full article

In this study, compression, rebound, and triaxial tests were conducted to investigate the strength and deformation behavior of lignin-fiber-reinforced sandy soil under various conditions, with a focus on the influence of fiber content (FC) on its mechanical properties. Based on the experimental results, a modified Duncan–Chang model suitable for lignin-fiber-reinforced sandy soil was established. The results indicate that the addition of lignin fibers increases the compressive deformation of sandy soil. Under saturated conditions, the fibers suppress compressive deformation while enhancing rebound deformation, with the minimum compressive deformation observed at an FC of 0.5%. Quantitative analysis shows that as FC increases, the effect of dry and saturated states on compression and rebound indicators gradually diminishes. When the FC reaches 5%, these indicators are no longer significantly affected by moisture conditions. The inclusion of fibers also improves the shear strength of sandy soil. With increasing FC and confining pressure, the stress–strain curves gradually transition to a strain-hardening type. At an FC of 5% and under confining pressures of 100 kPa and 200 kPa, the stress–strain curves exhibit a more pronounced hardening trend compared to those at other fiber contents; under a confining pressure of 300 kPa, the curve exhibits a strain-hardening type. As FC increases, the specimens initially show dilatancy followed by contraction. The curves calculated using the modified Duncan–Chang model are in good agreement with the experimental data, validating the model’s feasibility in capturing softening-type stress–strain behavior. Full article

The stability of retained roadways in closely spaced coal seams beneath a goaf is strongly affected by complex stress redistribution and the deterioration of roof structures under downward mining conditions. To address this issue, a combined approach involving theoretical analysis, numerical simulation, and field monitoring was adopted to investigate the deformation characteristics and stability control of gob-side retained roadways in short-distance coal seam groups. The movement characteristics of the roof and the deformation law of surrounding rock of the retained roadway under downward mining were revealed. An embedded short-arm beam structural model for a roof cutting retained roadway was established, and a calculation method for determining the required support resistance of the retained roadway was proposed. Based on this model, design criteria for the passive support system of the retained roadway were developed. A surrounding rock control technology with hollow grouting anchor cable support and low-disturbance directional roof cutting as the core was proposed, and the support resistance of a one-beam–four-column support system was determined to effectively limit roof subsidence. Field application results show that the surrounding rock displacement was controlled within 350 mm, and the roadway section shrinkage rate was maintained at 16.4%, indicating good stability of the retained roadway and satisfying the requirements of ventilation and transportation. This study provides a mechanical basis and practical guidance for stability control and support design of roof cutting retained roadways in closely spaced coal seams beneath goaf. Full article