Search Results (5,772)

Cistanche deserticola polysaccharide (CDP) exhibits pleiotropic bioactivities, yet its splenic-protective profile remains incompletely defined. Here, male ICR mice were challenged with cyclophosphamide (CTX) to establish an immunosuppressed model and concurrently treated with CDP. By integrating functional assays, splenic histopathology, and transcriptomic and proteomic analyses, we show that CDP dose-dependently restores splenic mass, rescues white-pulp atrophy, and suppresses megakaryocytic hyperplasia. Functionally, CDP rebalances pro-/anti-inflammatory cytokines, scavenges splenic ROS/MDA, and potentiates GSH-Px/SOD antioxidant capacity versus CTX alone. Multi-omics convergence (3103 DEGs; 1387 DEPs) delineated a CDP-distinctive signature related to innate immune recognition, oxidative stress buffering, and protease/ion-transport modules. Notably, transcriptional enrichment of neutrophil extracellular trap (NET)-associated proxies—synergized with NOD-like receptor/IL-17 signaling—suggests a putative innate-priming mechanism warranting functional validation, rather than confirmed pathway activation. Collectively, CDP mitigates CTX-induced splenic injury primarily through coupled redox restoration and transcriptional-level immune modulation. Full article

Underground coal mining can induce deformation and failure of overlying strata and ground surface, which seriously endangers the safety of human life and property. During mining, the immediate roof rock successively experiences initial caving (fixed support on four sides) and periodic caving (fixed support on three sides and free on one side). Different boundary conditions alter the unloading and deformation processes such as cracking and fracturing of immediate roof rock, thereby affecting its subsequent mechanical behavior of compaction and deformation, and resulting in differences in the movement law of overlying strata. In this paper, the numerical simulation method is adopted to investigate the variation laws of unloading and fracturing characteristics of immediate roof rock under initial caving and periodic caving with thickness-width ratio (t/w), length-width ratio (l/w), unloading stress (σ_u) and specimen strength (σ_c), and the corresponding action mechanism is revealed. The fractal evolution law of fractured immediate roof rock obtained from this study can quantitatively evaluate the compaction characteristics of caved rock, provide refined parameter support for surface subsidence prediction and possess guiding significance for stope surrounding rock control engineering. The results show that the fragments formed after the failure of immediate roof rock are mainly block-strip shaped under both first caving and periodic caving conditions. With the increase in the thickness-width ratio, the flexural rigidity of immediate roof rock increases and crack propagation is restrained, so that the particle-size–mass fractal dimension of fragments increases first and then decreases for the two caving modes. The increase in length-width ratio weakens the propagation of secondary fractures and raises the particle size of fragments, while the overall variation in particle-size–mass fractal dimension is small under the two working conditions. As the unloading stress continuously rises, the coupled tension-shear effect inside the rock gradually intensifies, and the failure mode changes from tension-shear failure to global shear failure. Accordingly, both the particle-size–mass fractal dimension and fractal dimension of crack distribution increase first and then decrease under first caving and periodic caving conditions. The increase in the strength of immediate roof rock raises the energy consumption during rock failure, and large-size fragments are more likely to be generated, which reduces the particle-size–mass fractal dimension and increases the particle size of fragments under both caving modes. Meanwhile, internal micro-fractures continuously initiate and propagate with the growth of rock strength. For specimens with relatively high strength, crack propagation is inhibited and the development of secondary fractures is weakened, leading to an evolution trend that the fractal dimension of crack distribution increases first and then decreases. Under identical parameter conditions, the particle-size distribution and crack complexity for first caving are mainly affected by geometric parameters; the particle size of fragments is primarily controlled by specimen strength; and the unloading stress threshold governs the transition of failure mode. For periodic caving, the crack-initiation location is first determined by asymmetric boundary constraints. The thickness-width ratio dominates the particle-size distribution of fragments, and unloading stress as well as specimen strength further regulate the complexity of cracks. Full article

The peptidoglycan (PG) sacculus of Gram-negative bacteria is continuously reorganized by a diverse enzymatic repertoire, including lytic transglycosylases, endopeptidases, carboxypeptidases, amidases and LD-transpeptidases, that operate alongside PG synthases to maintain envelope integrity throughout the cell cycle. This remodeling machinery has been extensively characterized in the context of growth and division and it is now emerging also as a key determinant of bacterial survival under non-growing and stress conditions. This review summarizes current knowledge on PG remodeling in Gram-negative bacteria, with emphasis on its regulation during stationary phase, environmental stress, and outer membrane perturbation. How these remodeling pathways, characterized by increased 3–3 cross-linking and enhanced PG–outer membrane coupling, contribute to survival under β-lactam exposure and how related enzymatic configurations can give rise to antibiotic tolerance and resistance is also discussed. Finally, recent progress in targeting PG remodeling enzymes, particularly lytic transglycosylases and peptidases, as adjuvant strategies to potentiate existing antibiotics are reviewed. In summary, PG remodeling represents a mechanistically validated but still underexploited target for addressing antibiotic tolerance and resistance in Gram-negative pathogens. Full article

The rapid penetration of converter-interfaced renewable generation has reduced effective inertia in islanded microgrids, making frequency regulation increasingly sensitive to renewable intermittency, generation outages, and storage stress. This paper proposes CMSA-OVSG–EMCS, a coordinated dual-layer control architecture for islanded PV–diesel microgrids with battery–supercapacitor hybrid energy storage. Its main novelty lies in coupling an adaptive grid-forming CMSA-OVSG layer, which updates virtual inertia and damping online according to disturbance severity, with a supervisory EMCS that coordinates multi-time-scale HESS power sharing through the common DC link. In contrast to OVSG approaches that rely on offline tuning of fixed controller parameters, the proposed framework uses physics-constrained multi-scenario optimization to jointly account for frequency response, DC-link regulation, converter operating limits, and battery stress. Nonlinear simulations under load variations, renewable intermittency, PV disconnection, and diesel-generator outage show that the proposed method consistently delivers the strongest transient performance among the tested controllers. In the worst-case diesel-generator outage scenario, it reduces the maximum ROCOF by 51.5% and the battery-stress index by 27.5% relative to the strongest benchmark controller. Full article

A research framework integrating material testing, constitutive fitting, thermo-mechanical coupled simulation, and local refined analysis was developed for 06Cr15Ni25Ti2MoAlVB superalloy bolts. High-temperature tensile and creep tests were performed to establish the Ramberg–Osgood elastic-plastic model and Norton–Bailey creep model. Based on CFD-derived thermal boundary conditions, a thermo-mechanical-creep coupled finite element model was constructed to investigate bolt temperature, global stress response, local thread stress concentration, and fastening-force evolution under rated operating conditions. The results show that the maximum temperature of the exhaust manifold is about 885 °C, while the maximum bolt temperature reaches about 250 °C. The global model predicts a maximum bolt equivalent stress of approximately 513 MPa near the initial threaded contact region. The refined thread model reveals severe stress concentration at the root of the first engaged thread, with a peak stress of about 905 MPa. After 1000 h of high-temperature holding and cooling, bolt fastening force decreases irreversibly by an average of 17.6%, with a maximum reduction of 28.27%. The results provide a reference for fastening design, fastening-force retention evaluation, and life assessment of bolted connections in high-temperature exhaust systems. Full article

The aluminum/steel hybrid body structure represents one of the key breakthrough directions for automotive lightweighting. However, aluminum and steel differ significantly in their thermophysical properties, making it difficult to achieve high-quality joining between them using conventional fusion welding methods. To address this challenge, the present study employs ultrasonic welding technology to achieve spot welding in a steel/aluminum/steel three-layer plate configuration. The experimental welding of the three-layer sheets and interfacial phase identification were first carried out, followed by the development of an ultrasonic vibration–thermal–mechanical coupled numerical simulation model, the accuracy of which was verified through experiments. On this basis, the dynamic evolution of the temperature and stress fields during the ultrasonic welding process was systematically revealed. Furthermore, this novel engineering simulation case was introduced into the teaching of the course Engineering Finite Element and Numerical Computation yielding favorable educational outcomes. Full article

The knee is a mechanically demanding synovial organ in which joint loading, tissue deformation, cellular mechanotransduction and matrix turnover are coupled. This narrative review critically links those scales and asks where the evidence is sufficiently mature for mechanistic or clinical inference. PubMed/MEDLINE and Europe PMC were searched from database inception to 20 July 2026 using structured terms for knee biomechanics, cartilage and osteochondral mechanobiology, finite element modelling, mechanosensitive channels, osteoarthritis, machine learning and digital twins. Landmark studies were selected for foundational models, while recent studies were prioritised for causal experiments, validation and translation. Instrumented implants show that common activities generate tibiofemoral forces of several times body weight, but tissue-level exposure also depends on muscle co-contraction, geometry and material properties. Biphasic and fibril-reinforced models explain how those loads become stress, strain, fluid pressure and osmotic signals. At the cell scale, TRPV4 and PIEZO1/2 participate in overlapping, context-dependent calcium signalling rather than a universal protective–pathological binary; most causal evidence remains preclinical. Osteoarthritis is therefore framed as a mechanically amplified feedback process involving cartilage, bone, synovium and systemic modifiers. Computational degeneration models and machine-learning surrogates are increasingly informative, although prospective validation, parameter identifiability and uncertainty propagation remain limiting. The review’s added value is an explicit transmission-and-validation framework that connects whole-joint observables to molecular responses while labelling the evidence source and translational readiness at every step. Full article

Background: Global antibiotic consumption continues to rise across pediatric and adult populations, while the genotoxic consequences of host eukaryotic exposure remain less systematically characterized than the parallel problem of antimicrobial resistance. Several lines of evidence, from molecular cytogenetics, redox biology, and systems toxicology, now permit a more mechanistically resolved synthesis of antibiotic-induced genome stress than was previously possible, although a substantial fraction of this evidence is preclinical and warrants cautious clinical extrapolation. Scope: This narrative review evaluates the molecular mechanisms, cytogenetic biomarkers, and translational implications of antibiotic-induced genotoxicity, with a primary focus on six clinically prominent classes (fluoroquinolones, nitroimidazoles, aminoglycosides, macrolides, β-lactams, and tetracyclines) and a brief extension to glycopeptides and glycylcyclines. We organize the evidence around three convergent mechanistic axes rather than around individual drugs. Key findings: Accumulating evidence supports three intersecting off-target axes: (i) eukaryotic topoisomerase II interference, principally documented for fluoroquinolones; (ii) mitochondrial dysfunction, reflecting the evolutionary kinship between the mitoribosome and bacterial ribosomes; and (iii) inflammation-coupled redox stress, often amplified by microbiome perturbation. These pathways converge on a common spectrum of DNA lesions—including double-strand breaks, oxidatively modified bases, replication-fork stalling, and chromosomal mis-segregation) detected by complementary assays (CBMN-Cyt, comet, γH2AX, and oxidative and mitochondrial biomarkers). Pediatric, pregnant, geriatric, and oncology populations may represent biologically distinct susceptibility strata, although direct human evidence for several of these inferences remains limited. Limitations: Causal inference is constrained by infection as a confounder, frequent use of supratherapeutic in vitro concentrations, reliance on immortalized cell lines that may not recapitulate primary-cell repair capacity, inter-laboratory variability across cytogenetic assays, and a marked scarcity of pediatric and pregnancy biomonitoring data. Most existing positive signals derive from preclinical models; clinically validated long-term outcomes, particularly carcinogenic endpoints, remain inconsistently demonstrated for most antibiotic classes outside metronidazole. Conclusions: Antibiotic-induced genotoxicity appears to be a measurable and mechanistically tractable dimension of drug safety, though its clinical magnitude in real-world exposure scenarios requires further investigation. Integrating multi-omics, microphysiological systems, single-cell genotoxicology, and AI-assisted prediction may improve risk resolution, particularly in vulnerable populations. We argue that antimicrobial stewardship discussions should consider host genome integrity alongside resistance, while remaining mindful that the mechanistic case currently outpaces clinical-endpoint validation. Full article

Peatlands, critical global carbon sinks, are facing increasing threats from climate change-driven heatwaves and droughts. These threats can cause a midday depression in carbon uptake through photosynthetic inhibition. Using high-temporal-resolution solar-induced chlorophyll fluorescence (SIF; ~30 s) and chamber-based CO₂ flux measurements, we investigated the coupling between SIF and gross primary production (GPP) during extreme events (air temperature > 25 °C and vapour pressure deficit > 15 hPa) in a northern peatland. Our results show that SIF tracks GPP closely under non-stress conditions (daily R² = 0.86–0.96). However, during combined heat and drought stress, midday correlations collapsed (Case A: R² = 0.04 on 27 June; Case B: R² = 0.15 and 0.01 on 29 and 30 June, respectively), indicating severe decoupling. Importantly, we discovered legacy effects from multi-day heat exposure: on 26 June, vegetation with prior cumulative stress (Case A) showed weak morning coupling (R² = 0.07), while vegetation without prior stress history (Case B) maintained strong coupling (R² = 0.93). This suggests that cumulative stress alters baseline physiology and can exacerbate midday mismatches; therefore, not just current condition controls photosynthetic regulation. These findings highlight limitations of SIF-based GPP estimation at sub-daily timescales during stress, particularly in heterogeneous peatland systems where canopy composition and physiological responses could vary among plant functional types. Full article

Background/Objectives: Recurrent pregnancy loss (RPL) has traditionally been investigated predominantly through maternal factors, while the clinical role of paternal assessment remains inconsistently defined. Current guidelines differ substantially regarding semen analysis, sperm DNA fragmentation (SDF), genetic testing, and referral for andrological evaluation. This review aimed to compare contemporary guideline recommendations, critically appraise the directness, prognostic value, and clinical utility of the supporting evidence, and classify paternal assessment strategies as routine, selective, or investigational. Methods: A structured narrative review was conducted using PubMed and Scopus searches through June 2026. International RPL, obstetric, reproductive medicine, and andrology guidelines were compared. Evidence from systematic reviews, meta-analyses, clinical studies, and clinically relevant molecular investigations was evaluated according to its directness to RPL populations, diagnostic and prognostic value, and evidence that test-guided interventions improve miscarriage or live-birth outcomes. Results: Routine paternal assessment should include age, reproductive and medical history, body weight, lifestyle, medication exposure, and relevant environmental or occupational risks. Conventional semen analysis is appropriate primarily when RPL coexists with infertility or suspected male reproductive disease. SDF is the most extensively studied advanced paternal biomarker and is frequently elevated in RPL cohorts, but findings vary by assay and comparator population, while prospective prediction of subsequent live birth and benefit from SDF-directed treatment remain unproven. Parental karyotyping has established counselling value but should be risk-stratified. Sperm aneuploidy testing, oxidative stress assays, seminal microbiome profiling, epigenetic biomarkers, and biomarker-directed interventions remain investigational. Conclusions: Paternal assessment in RPL should be couple-based, clinically targeted, and evidence-informed. Current evidence supports routine clinical evaluation, selective use of semen analysis, SDF testing, genetic assessment, and reproductive urology referral, and restriction of unvalidated biomarkers and treatments to research settings. Full article

Permeability models are essential for quantitatively describing coal permeability evolution and predicting gas migration during deep mining. Deep coal subjected to mining disturbance commonly exhibits pronounced nonlinear changes in permeability, limiting the applicability of conventional models. In this study, coal is idealized as a dual-component medium comprising the matrix and fractures, and deformation of both components induced by mining-related stress changes and gas adsorption is incorporated into the model. The conventional Weibull statistical damage variable is generalized to a fractional-order form using the Caputo derivative, yielding a Mittag–Leffler-type damage evolution law. By coupling this formulation with matrix–fracture deformation and an exponential damage–permeability term, a fractional-order damage-based permeability model is established to describe the complete evolution from elastic deformation through pre-peak damage to post-peak failure. The model parameters are calibrated separately using published datasets for protective-seam mining, top-coal caving, no-pillar mining, and a full-process loading case. The calibrated model yields coefficient of determination (R²) values of 0.9374, 0.9625, 0.9875, and 0.9980, respectively. The identified fractional order is λ = 1 for the three mining-disturbance datasets, whereas the full-process dataset yields λ = 0.7734. For the full-process dataset, the fractional-order model reduces root mean square error (RMSE) and mean absolute error (MAE) by approximately 31.4% and 34.7%, respectively, compared with its integer-order counterpart. Sensitivity analysis shows that λ, p, ε_d, and γ play distinct roles in permeability evolution. At an axial strain of 0.8%, increasing ε_d from 0.721% to 1.121% decreases k/k₀ from 2.6919 to 1.3433, whereas increasing γ from 0 to 2.543 increases k/k₀ from 1.0003 to 3.0334, indicating that ε_d and γ strongly affect the strain level and magnitude of permeability enhancement, respectively. The proposed model provides an effective tool for characterizing the nonlinear permeability evolution of deep coal under mining disturbance. Full article

Photovoltaic technology selection in Gulf Cooperation Council (GCC) desert environments is affected by coupled dust, thermal, ultraviolet (UV), humidity, and salinity stresses, which are not fully represented by static weighting and additive multi-criteria decision-making models. This study develops a GCC evidence-calibrated nonlinear decision-support framework that integrates published literature-derived GCC/desert-stress calibration, adaptive hybrid entropy–desert weighting, and bipolar fuzzy Einstein aggregation. The framework is applied to compare passivated emitter and rear cell (PERC), tunnel oxide passivated contact (TOPCon), and heterojunction technology (HJT) photovoltaic technologies using calibrated evidence from Qatar, the United Arab Emirates, Saudi Arabia, and Oman. The results show that dust tolerance receives the highest final hybrid weight (0.258), followed by thermal resistance (0.228), UV resistance (0.207), efficiency (0.173), and cost effectiveness (0.134). The nonlinear Einstein aggregation ranks HJT first (0.889), followed by TOPCon (0.861) and PERC (0.742). Benchmark comparison with TOPSIS, VIKOR, and PROMETHEE II shows high rank agreement, while Monte Carlo perturbation analysis indicates that HJT preserves the first rank in 93% of perturbation runs. The proposed framework links PV technology selection with published GCC desert-stress evidence and provides a reproducible basis for technology prioritization in harsh solar energy deployment environments. A stress-to-decision translation table is also provided to clarify how desert degradation mechanisms are converted into decision criteria and reusable selection guidance. Full article

Background/Objectives: Brain-derived neurotrophic factor (BDNF) and antioxidant networks mediated by Selenoprotein P (SEPP1) are core drivers of structural neuroplasticity and blood–brain barrier integrity, yet their co-regulatory behavior during subacute stroke neurorehabilitation remains poorly understood. This pilot study quantified concurrent changes in serum BDNF and SEPP1 during rehabilitation. Methods: Sixteen subacute post-stroke patients with mild stroke severity were assigned to an intensive multi-modal neurorehabilitation protocol incorporating high-intensity interval training (Treated, n = 7) or standard care (Control, n = 9); the biomarker sampling window averaged 73.4 days. Fasting venous blood was collected at baseline and post-intervention and analyzed by ELISA. Results: BDNF changes (ΔBDNF) differed significantly between arms (U = 57.0, p = 0.0081): the Treated cohort showed a uniform decrease (mean Δ: −0.240 ± 0.103 ng/mL), while Controls showed stabilization or a slight increase (mean Δ: +0.118 ± 0.339 ng/mL). ΔBDNF and ΔSEPP1 were significantly, positively correlated across the cohort (ρ = 0.596, p = 0.015). Conclusions: The BDNF decline in the Treated group is consistent with the “central sink” hypothesis, but may more plausibly reflect stress/cortisol-mediated suppression induced by the high training intensity, contrasting with increases typically reported after moderate-intensity subacute-phase exercise. The collinear coupling with SEPP1 suggests a link between neurotrophic synthesis and antioxidant buffering during post-stroke tissue remodeling, though this correlational finding does not by itself establish a single, coordinated mechanism. Full article

High-speed permanent magnet motors, due to their high speed, compact size, and light weight, are increasingly widely used in renewable energy systems, electric pump drives, fuel cell air compressors, and other fields. As a core component of high-speed permanent magnet motors, the reasonable design of the rotor system structure directly affects motor stability. To ensure the safe and reliable operation of high-speed permanent magnet motors, this paper designs the structure of a certain type of high-speed electric pump rotor. First, the actual interference amount between the rotor permanent magnet and the high-temperature alloy sleeve under high-speed and high-temperature conditions is considered, and radial and tangential stress analyses are performed on both the rotor and high-temperature alloy sleeve to determine the optimal interference amount. Second, based on rotor dynamics and fluid–structure coupling theory, the natural frequency and critical speed of rotors under wet and dry modals are studied; on this basis, harmonic response analysis and fatigue assessment were conducted; furthermore, an elastoplastic mechanical model of the rotor sleeve is introduced to analyze the effects of interference amount and rotational speed on the sleeve’s yield failure; finally, the dynamic safety of the high-speed rotor structure is verified through modal tests and overspeed operation tests. The results show that the optimal interference amount for the rotor is 0.02 mm; the first-order critical speeds in both dry and wet modals are well above the rated speed of 40,000 rpm, with no risk of resonance; the minimum cycle for fatigue life is 6.9 × 10⁵, meeting usage requirements; the equivalent force on the rotor sleeve increases with speed and interference amount; when the speed exceeds 44,000 rpm, the sleeve undergoes plastic deformation and failure; modal test error is less than 5%. This paper provides theoretical basis and experimental support for the rotor structure design and strength evaluation of high-speed permanent magnet motor drive equipment. Full article

This study evaluated the synergistic effects of sodium chloride (NaCl) and cytidine monophosphate (CMP) on enhancing the co-production of astaxanthin and fatty acids while suppressing secondary cell wall (SCW) formation in Haematococcus lacustris (synonym: H. pluvialis) under high-light stress. An orthogonal design identified the optimal combination (0.5 g/L NaCl and 0.5 mM CMP), which significantly increased astaxanthin yield by over 35.6% and total fatty acid yield by 28%, while maintaining 96.8% of cells in motile state (SCW-deficient). Physiological analyses revealed elevated reactive oxygen species levels, concomitant with higher actual photochemical efficiency (Fv′/Fm′) and relative electron transport rates II (rETR(II)) along with enhanced non-photochemical quenching (NPQ) capacity, and metabolic reprogramming characterized by the accumulation of lipids, sugars, and starch alongside decreased protein yield. Metabolomics indicated reduced carbon supply for SCW polysaccharide biosynthesis, coupled with decreased protein yield and altered amino acid profiles characteristic of nitrogen-limited metabolism, which collectively favored the reallocation of carbon resources toward nitrogen-free high-value products. Transcriptomics confirmed the downregulation of SCW component biosynthetic genes and the upregulation of the methylerythritol phosphate (MEP) pathway and astaxanthin biosynthetic pathway. Scale-up experiments validated this strategy for producing astaxanthin-rich motile cells, offering a promising approach for microalgal biorefinery. Full article