Search Results (4,135)

Uhthoff’s phenomenon (UP) is a transient, fully reversible exacerbation of pre-existing neurological deficits in multiple sclerosis (MS) patients, triggered by minor elevations in core body temperature. In clinical practice, UP is a frequent source of distress, often misidentified as an acute inflammatory disease relapse. This narrative review provides a critical analysis of UP, addressing methodological heterogeneity in its epidemiological estimates, its clinical presentation, and its differential diagnosis from true relapses. Mechanistically, we synthesize traditional concepts of temperature-dependent conduction block with modern insights into neuroenergetic failure, mitochondrial dysfunction, inflammatory mediators, and autonomic dysregulation. Furthermore, this work delineates current management strategies, establishing a clear distinction between robust evidence-based interventions and expert-informed practical guidance for patient education, physical rehabilitation planning, targeted active/passive cooling, and pharmacological approaches. Characterized as a pseudo-relapse, UP occurs independently of novel focal neuroinflammation. In conclusion, an isolated episode of Uhthoff’s phenomenon (UP) represents a transient, functional conduction block and does not inflict acute, permanent structural damage to the axon. However, emerging frameworks suggest that frequent, repeated episodes subject the already demyelinated axon to recurrent metabolic strain. Over time, these successive neuroenergetic crises do not directly destroy the fiber, but they may gradually exhaust the cell’s metabolic reserve. This cumulative stress potentially increases long-term secondary axonal vulnerability, making the axon more susceptible to the progressive neurodegenerative processes inherent to multiple sclerosis. Full article

Metabolic dysfunction-associated steatohepatitis (MASH) represents a systems-level disorder driven by the interplay of metabolic stress, bile acid dysregulation, gut microbiota remodeling, and immune activation. Because no single experimental platform recapitulates the full spectrum of human disease—from steatosis and fibrosis to spontaneous hepatocellular carcinoma (HCC)—model selection must be guided by the dominant biological mechanism under investigation rather than by phenotypic similarity alone. This review proposes a mechanism-oriented framework for model selection, illustrated by representative experimental systems, including the intensified high-fat/high-cholesterol diet supplemented with cholate (iHFC diet) and Tsumura–Suzuki obese diabetic (TSOD) and non-obese (TSNO) mouse models. The iHFC diet provides a reproducible platform for interrogating the bile acid–microbiota–macrophage axis in fibro-inflammatory progression, whereas TSOD mice represent a valuable system in which spontaneous MASH–HCC development can emerge under chronic metabolic imbalance without engineered oncogenic triggers. TSNO mice serve as a controlled background for dissecting bile acid-dependent susceptibility. We further integrate hepatocyte mitochondrial dysfunction, immune remodeling, and stellate cell activation into this triadic framework and position additional diet-induced, genetic, and in vitro models within a complementary translational landscape. Together, this mechanism-centered framework provides a practical roadmap for rational model selection and enhanced translational precision in MASH and metabolic hepatocarcinogenesis research. Full article

Ultra-deep circular shafts are increasingly deployed in congested urban environments, yet their structural performance in highly sensitive soft clay remains susceptible to diaphragm wall panel joints, structural imperfections, and complex interactions with adjacent structures. This study presents a high-fidelity three-dimensional (3D) numerical investigation into the excavation behavior of an ultra-deep circular shaft with a diameter of 30 m and an excavation depth of 56.3 m in Shanghai soft clay by synthesizing high-resolution field monitoring with advanced finite element modeling. The numerical framework was established in PLAXIS 3D utilizing the Hardening Soil model with small-strain stiffness (HSS), explicitly incorporating an equivalent structural stiffness reduction scheme (0.8 vertically and 0.5 circumferentially) to capture panel segmentation, joint compliance, and concrete cracking. The reduced-stiffness model successfully reproduces the measured deep-seated bulging profiles and internal force distributions with high fidelity. The findings reveal exceptional deformation control capabilities of the circular geometry, yielding a maximum lateral wall deflection of merely 9.1 mm (0.016%H_e), which is significantly smaller than the normalized deformation ratio of 0.3%H_e observed in five analogous rectangular excavations in Shanghai. The numerical results indicate that circumferential compression governs the overall load transfer behavior, while vertical bending response remains relatively limited. Furthermore, a pronounced circumferential anisotropy in wall deformation is governed by asymmetric boundary conditions, where localized Metro Jet System (MJS) ground improvement significantly restrain movements, whereas the non-grouted area experience peak deflections. Crucially, interaction with the adjacent external diaphragm walls of ancillary structures induces a complex 3D stress redistribution rather than a beneficial shielding effect, amplifying the peak shaft wall displacement by nearly 62.8% (from 4.73 mm to 7.70 mm). These insights underscore the criticality of integrating small-strain soil mechanics, equivalent structural degradation, and adjacent structural boundaries into predictive design protocols for ultra-deep circular retaining systems. Full article

Continuous laser cladding of Ni-based composite coatings commonly suffers from coarse microstructures, high residual stress, severe cracking susceptibility, and limited wear performance. Although substrate preheating is an effective strategy for crack suppression, it inevitably induces microstructural coarsening and deteriorates mechanical and tribological properties, while the independent and coupled effects of pulsed laser modulation and preheating on (Ti, V)C/Ni coating performance remain insufficiently quantified and clarified. To address these technical gaps, this work fabricates (Ti, V)C/Ni composite coatings on Cr12MoV die steel via pulsed laser cladding. An L₁₆ orthogonal experiment is employed to systematically investigate the influences of average power, duty cycle, and pulse frequency on coating hardness, and the optimal pulsed laser parameters are determined as 1750 W average power, 65% duty cycle, and 10 Hz pulse frequency. Under optimized parameters, the pulsed-laser-clad coating achieves a maximum hardness of 898.6 HV_0.2, exhibiting 10.2% higher hardness and 41.4% better wear resistance than its continuous laser-clad counterpart, owing to the refined microstructure and enhanced grain-strengthening effect induced by rapid pulsed thermal cycling. Further comparative experiments demonstrate that substrate preheating combined with pulsed laser cladding effectively eliminates coating cracks and reduces residual stress by alleviating concentrated thermal strain. Nevertheless, preheating-induced microstructure coarsening slightly reduces the hardness and wear resistance of the composite coating compared with the purely pulsed laser-processed coating. In summary, pure pulsed laser processing dominates the improvement in wear resistance, whereas preheating mainly contributes to defect suppression and stress relief, enabling reliable engineering application of laser-clad coatings. Full article

Endocrine system hormones regulate growth, metabolism, and reproduction. These hormones often function at low concentrations, making them especially susceptible to disruption via endocrine-disrupting chemicals (EDCs) that can mimic, block, or disturb normal hormone signaling. Among these EDCs, polychlorinated biphenyls (PCBs) and per- and polyfluoroalkyl substances (PFAS) are of special concern for human health because they are persistent and bioaccumulate. In this review, we focus on effects of PCBs and PFAS on female reproduction, with emphasis on steroidogenesis, ovarian function, fertility, and assisted reproductive technology (ART) outcomes. We describe the chemical properties and exposure routes of PCBs and PFAS, and how these features explain their long half-lives and ability to transfer to the female reproductive system and fetus. Evidence suggests that both PCBs and PFAS can reduce follicle numbers, disturb oocyte quality, and increase oxidative stress and apoptosis. Human and animal data also link PCB and PFAS exposure with altered ART outcomes. Together, the literature indicates that persistent exposure to PCBs and PFAS poses a significant and long-lasting risk to female reproductive health. Full article

Background: Drought is one of the major abiotic stresses that affect and limit cotton growth and production. However, transcriptome differences between drought-tolerant and drought-susceptible cotton lines remain largely unknown. Methods and Results: In this study, two upland cotton cultivars, the drought-tolerant XLZ80 and drought-sensitive XLZ61, were subjected to comparative phenotypic and transcriptomic analyses under drought stress. Phenotypic evaluation showed that XLZ80 exhibited only mild leaf wilting, whereas XLZ61 displayed severe wilting symptoms after drought stress. RNA-seq analysis revealed that differentially expressed genes in XLZ80 were specifically enriched in pathways related to phosphatidylinositol signaling, phenylalanine metabolism, MAPK signaling, and betaine biosynthesis, while DEGs in XLZ61 were primarily involved in basal metabolic processes. A total of 9302 core DEGs were identified across and between the cultivars and were grouped into eight dynamic expression clusters containing 841 transcription factors. Weighted gene co-expression network analysis further identified three key modules associated with drought tolerance. Twelve hub genes, including GH_D02G2153 (MADS-box) and GH_A05G1087 (bZIP), were identified as central regulators. qRT-PCR validation confirmed that these genes exhibited faster and stronger induction in the tolerant cultivar. In summary, this study deepens the transcriptional-level understanding of drought stress responses in cotton and provides valuable gene resources for breeding drought-resistant cultivars. Full article

Stress corrosion cracking (SCC) of prestressing steel threatens prestressed concrete structures with sudden, brittle failure and minimal visible warning. While mechanical stress, localized corrosion, and hydrogen uptake are recognized drivers, the mechanisms connecting sulfide exposure in cementitious materials to hydrogen uptake and crack initiation at the steel–concrete interface remain poorly understood. This review synthesizes the coupled electrochemical, mechanical, metallurgical, and environmental processes governing SCC, with particular emphasis on the interactions of sulfide species with chloride ingress, carbonation, pitting, and hydrogen-assisted cracking under sustained tensile stress. Evidence indicates that sulfides weaken passive-film protectiveness and facilitate hydrogen entry, while localized corrosion and acidification create favorable conditions for crack initiation and propagation. Because SCC susceptibility emerges from the combined effects of environmental exposure, steel microstructure, and mechanical loading, isolated environmental parameters cannot adequately predict risk. Accelerated laboratory tests offer comparative insight but have limited representativeness of the complex conditions of prestressed concrete. A critical gap persists: no quantitative relationship has yet been established between cement sulfide content, sulfide availability at the steel surface, hydrogen uptake, and actual SCC susceptibility. Bridging this gap requires service-representative experiments on stressed prestressing steel embedded in mortar or concrete to develop reliable durability criteria and move beyond precautionary regulatory limits. Full article

Roadways serving island longwall panels are highly susceptible to severe asymmetric deformation under extreme eccentric loading from multiple adjacent goafs. To address the difficulties in characterizing the surrounding rock load imbalance and the high false-negative rates of conventional algorithms under extremely imbalanced monitoring data, an intelligent assessment method integrating spatially asymmetric physical features with cost-sensitive learning was developed. Implicit equation analysis and numerical simulation clarified the mechanical mechanism by which principal stress axis deflection induces butterfly-shaped asymmetric rotational failure, enabling the construction of dimensionless integrated asymmetry and structural transfer asymmetry coefficients. Reconstruction of the cost-sensitive objective function increased the recall rate for hazardous samples from 37.5% (baseline model) to 92.2%, while maintaining a precision of 96.7%. Following the field implementation of a three-tier differentiated roadway control scheme, the integrated asymmetry coefficients at critically eccentrically loaded stations (i.e., Station 12 and Station 07) remained below 0.2 during the monitoring period, enabling real-time intelligent perception and proactive stability control of roadways subjected to complex eccentric loading. Ultimately, this study confirms the viability of integrating physics-informed features with machine learning, demonstrating significant potential for advancing the transition toward intelligent and proactive safety management in complex underground construction. Full article

As environmental pressures intensify, sustaining ecologically and economically important marine species such as the American lobster has become an increasing challenge. Climate-driven stressors are expected to disproportionately affect early life stages of the American lobster (Homarus americanus), as sea surface temperatures are warming more rapidly than benthic habitats. In addition, environmental pollutants, including micro- and nanoplastics, trace metals, persistent organic pollutants, and per- and polyfluoroalkyl substances, can interact with climate change to exacerbate physiological stress. Previous studies have demonstrated that changes in temperature, salinity, and pH significantly influence development, moulting, cardiac function, survival, and disease susceptibility in H. americanus. In this context, aquaculture-based approaches are being explored as complementary tools to support stock resilience and reduce reliance on wild populations. Recirculating aquaculture systems (RAS) offer a controlled framework to investigate the combined effects of environmental stressors on H. americanus physiology while assessing the feasibility of closed-system rearing. Overall, this review synthesizes current knowledge on the physiological responses of H. americanus to multiple environmental stressors, with particular emphasis on identifying optimal rearing conditions in RAS. By integrating these findings, the review aims to inform strategies for improving the sustainability and long-term viability of American lobster production under changing environmental conditions. Full article

The dissimilar metal welded joints at the safe ends of nuclear primary circuits are highly susceptible to stress corrosion cracking (SCC) initiation in high-temperature, high-pressure water environments. Existing predictive models are predominantly based on homogeneous material assumptions, making it challenging to accurately evaluate the actual failure behavior of welds caused by mechanical property heterogeneity. Consequently, based on the mechanical gradient obtained from hardness tests, this study constructs a finite element model with continuously varying mechanical properties to quantitatively investigate SCC behavior under different crack characteristics. The analysis demonstrates that mechanical heterogeneity significantly influences the crack tip mechanical fields: When the crack is located proximal to the sub-interface (d = 1 mm), the severe mechanical mismatch induces a sharp increase in creep strain, resulting in a peak SCC propagation rate approximately 14.6% higher than those at d = 3 mm. Furthermore, extending the crack length at the weld center (a/W from 0.45 to 0.60) expands the plastic strain zone along the propagation direction, driving an approximately 43.6% increase in the crack growth rate. The heterogeneous model, accounting for the local mechanical gradient, can more accurately reveal the influence laws of crack position and length on SCC propagation behavior, providing theoretical support for improving life prediction accuracy and in-service inspections. Full article

Acinetobacter baumannii is a major nosocomial pathogen characterized by multidrug resistance and persistence in hospital environments. This study evaluated antimicrobial susceptibility and biofilm-forming capacity in ten clinical A. baumannii isolates obtained from a tertiary care hospital in Northwestern Mexico to explore phenotypic traits associated with persistence. Minimum inhibitory and bactericidal concentrations were determined using broth microdilution according to Clinical and Laboratory Standards Institute guidelines. All isolates were resistant to ciprofloxacin, whereas variable resistance was observed for tobramycin (60%) and ceftazidime (20%); all strains remained susceptible to colistin. Bactericidal assays revealed heterogeneous responses across antibiotics. Biofilm formation, assessed by crystal violet staining, showed that most isolates produced weak to moderate biofilms, while three strains were non-producers. Significant variability in biofilm biomass was observed (p < 0.001). Notably, no direct association was found between antimicrobial resistance profiles and biofilm-forming capacity, indicating phenotypic heterogeneity among isolates. These findings suggest that persistence-related traits in A. baumannii may not be solely predicted by resistance patterns, highlighting the complexity of adaptive responses under antimicrobial stress. Full article

CrN coatings prepared by physical vapor deposition may fail prematurely in localized regions during machining due to stress and high temperature. To address this problem, three groups of CrN coatings with different bias voltages were deposited on cemented carbide tools using cathodic arc ion plating. The influence of coating microstructure on cutting performance was investigated. The surface and cross-sectional morphologies of the coatings were observed using scanning electron microscopy. The crystal structures of the coatings were characterized using X-ray diffraction. The nanohardness values and elastic moduli of the coatings were measured using nanoindentation, and the coating–substrate adhesion was evaluated using a scratch tester. The residual stresses of the coatings were determined using the substrate bending method. The cutting performance of the coated tool was tested using a Computer Numerical Control (CNC) machine tool. The cutting process using coated tools was simulated using ABAQUS 6.14 software. The results indicated that, as the bias voltage increased, the droplets on the surface of the CrN coating became smaller and the structure became denser, but the thickness gradually decreased. The hardness increased from 18.59 GPa at 100 V to 24.57 GPa at 200 V, the bonding force increased from 72.6 N to 78.5 N, and the residual stress also increased to −2.22 GPa. Cutting tests showed that the cutting performance of the 200V-CrN coating was nearly twice that of the 100V-CrN coating. According to the microstructure and finite element simulation results after cutting, the 200V-CrN coating with a dense structure and higher residual compressive stress exhibited better stress-absorption capacity and was less susceptible to wear or fracture during the cutting process, thereby extending tool life. Full article

Cutaneous melanoma is the most lethal skin cancer, and risk is strongly shaped by pigmentary phenotype. The red-hair color phenotype, marked by red hair, fair skin, freckling, and poor tanning, carries elevated melanoma risk driven largely by loss-of-function variants in the melanocortin 1 receptor gene (MC1R). This risk is not explained by reduced ultraviolet protection alone. Impaired MC1R signaling shifts melanogenesis from photoprotective eumelanin toward pheomelanin, a pigment associated with oxidative stress and partly ultraviolet-independent melanomagenesis. MC1R may also influence melanoma susceptibility through pigment-independent effects on DNA damage responses, repair signaling, and genomic stability. These mechanisms support investigation of MC1R genotype, visible phenotype, nevus burden, pigment chemistry, and imaging-derived lesion metrics as complementary tools for risk stratification. Diagnosis is also distinctive in this population. Amelanotic and hypomelanotic melanomas are associated with the red-hair color phenotype, and their low pigmentary contrast may delay recognition and contribute to diagnosis at a more advanced stage. This review integrates genetic, molecular, biomarker, diagnostic, and therapeutic literature specific to red-haired populations. We argue that elevated biological susceptibility and diagnostic difficulty compound one another, and we outline priorities for MC1R-informed surveillance, imaging adapted to pigment-poor disease, pharmacologic modulation of MC1R-related pathways, and prospective risk models integrating genotype, phenotype, nevus burden, pigment biology, and imaging. Full article

This study evaluated the effects of four LED lighting sources—full spectrum (FS), white (White), battery-powered lantern (Lantern), and monochromatic green (Green)—on Pekin duck growth performance, eye development, fear responses, stress susceptibility, gut health, and skeletal parameters. A total of 432 day-of-hatch Pekin ducklings were assigned to one of four light treatments (n = 9 replicate pens per treatment) and reared from d 0 to 35. Body weight, feed intake, and mortality-corrected feed conversion ratio were recorded, and on d 35, tonic immobility, inversion, physical asymmetry, heterophil-to-lymphocyte ratio, plasma corticosterone, ileal histomorphology, and tibia bone parameters were assessed. Green and White treatments produced greater body weight (3.28 and 3.27 kg; p = 0.002) and feed intake (145.2 and 143.3 g/d; p = 0.002) than FS and Lantern treatments, while feed conversion ratio did not differ (p = 0.73). Green and White ducks exhibited shorter tonic immobility latency to right (p = 0.02), lower composite asymmetry scores (p < 0.001), lower plasma corticosterone (p = 0.002), greater ileal villus-height-to-crypt-depth ratio (p = 0.002), and greater tibia-breaking strength (p = 0.001) compared with FS and Lantern ducks. These results demonstrate that monochromatic green and standard white LED lighting improve growth performance and multiple welfare indicators over full-spectrum and lantern-style LED sources in commercial Pekin duck production. Full article

Autism spectrum disorder (ASD) risk reflects genetic susceptibility and modifiable environmental exposures acting during fetal and early postnatal critical periods. Building on our prior two-path model, in which folate receptor autoantibody-driven cerebral folate deficiency and oxidative stress/neuroinflammation converge on disrupted neurodevelopment, this review provides the first full mechanistic treatment of environmental pollutants within that framework. We synthesize evidence across seven exposure categories: micro/nanoplastics, plastic-associated endocrine-disrupting chemicals, ambient/indoor air pollution, tire wear particles and 6PPD-quinone, heavy metals and pesticides, industrial chemicals and persistent organic pollutants, and ultra-processed food intake as a parallel, non-pollutant contributor to the same inflammatory pathway. Human biomonitoring of micro/nanoplastics has progressed beyond detection in the placenta, brain and breast milk to direct evidence of placental genotoxicity and fetal endocrine disruption, complementing rodent data linking early-life exposure to impaired corticogenesis, disrupted microglial synaptic pruning, and ASD-relevant behavioral deficits. Across categories, oxidative stress, barrier disruption, neuroinflammation, endocrine disruption, and epigenetic modification recur as convergent mechanisms acting on trimester- and age-specific windows of vulnerability. Genetic variation in folate pathway and mitochondrial genes, as well as folate/vitamin B sufficiency, are proposed as candidate effect modifiers rather than established protective factors to modify susceptibility to this pollutant burden. Most evidence is associational or mechanistic rather than trial-based; we grade evidence strength and translate findings into biomarker-guided clinical and population-level policy guidance. Full article