Search Results (10,189)

Monitoring the time-dependent rheological properties of 3D printed MgO-SiO₂-K₂HPO₄ is critical for optimizing the dynamic structural reconstruction ability. The collaborative analysis for the contribution of colloidal force based on EDLVO theory and the volume fraction of K-struvite (MgKPO₄·6H₂O) was conducted. Results showed that 20% silica fume (SF) was identified as the optimal content to achieve balanced rheo-mechanical performance (28 d compressive strength = 113.63 MPa, dynamic yield stress = 359.98 Pa, thixotropic area = 2.14 × 10⁴ Pa/s). The static yield stress development within 50 min exhibited two distinct stages: the initial rapid linear growth stage (Stage I, 5–30 min) dominated by colloidal forces (R² = 0.81 at 20% SF), followed by the slow increased plateau (Stage II, 30–50 min) correlated with K-struvite volume fraction. Also, dual crystallization pathways of K-struvite included direct precipitation from supersaturated Mg²⁺, K⁺, PO₄^3- ionic species and transformation from potassium-deficient phosphate phase. Quantitative results establish a predictive framework for microstructural construction, enabling precise control of structural build-up and 3D printability in MgO-SiO₂-K₂HPO₄ cementitious composites. Full article

Circulatory disturbances in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) present significant challenges in interventional cardiology. This review examines the pathophysiological mechanisms, management strategies, and outcomes associated with these hemodynamic complications, ranging from transient hypotension to severe cardiogenic shock (CS). The complex interplay between myocardial ischemia, reperfusion injury, and procedural stress creates a dynamic circulatory environment that requires careful monitoring and intervention. The review analyzes various causes of circulatory disturbances, including vasovagal reflexes, allergic reactions, cardiac arrhythmias, acute ischemia, and procedural complications. It emphasizes the importance of early recognition and appropriate management of these conditions to improve patient outcomes. The progression from hypotension to CS is examined, with a focus on assessment tools, prognostication, and revascularization strategies. The role of mechanical circulatory support devices in managing severe circulatory compromise is discussed, including intra-aortic balloon pumps, Impella devices, and veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Recent randomized controlled trials have yielded mixed results regarding the efficacy of these devices, highlighting the need for a nuanced, patient-centered approach to their use. This comprehensive analysis provides clinicians with a framework for anticipating, identifying, and managing circulatory disturbances in ACS patients undergoing PCI. It underscores the importance of risk stratification, multidisciplinary approaches, and ongoing research to optimize patient care and improve outcomes in this high-risk population. Full article

Amaranthus palmeri is an aggressive, highly invasive weed that thrives across a wide range of adverse environments worldwide; nevertheless, the mechanisms underlying its rapid expansion remain largely unstudied. Glutathione peroxidase (GPX) is a crucial enzyme within the antioxidant defense system, belonging to the phylogenetic conserved family of oxidoreductases present in all living organisms. Despite its significance, the role of GPX in A. palmeri has not been reported. This study identified eight GPX genes (ApGPXs) in A. palmeri through comprehensive bioinformatics and gene expression analyses. The research examined the characteristics, evolutionary relationships, chromosomal mapping, gene structure, subcellular localization, conserved motifs, and cis-acting elements of these genes, as well as their evolutionary conserved functions in relation to Arabidopsis thaliana GPXs and RT-qPCR analysis under various stress conditions. The ApGPXs were distributed across scaffolds (2, 4, and 12) of the A. palmeri genome. Phylogenetic analysis grouped GPX genes into four subgroups, and conserved motifs were found within certain phylogenetic subgroups. We identified Actin8 as the most stable internal reference gene for A. palmeri under diverse stress conditions. Gene expression analysis revealed that ApGPXs participate in both early and late regulatory responses to oxidative stress induced by NaCl, high temperature, osmotic pressure, and glufosinate ammonium. The Arabidopsis GPX mutant (AT4G31870) exhibited a stronger flg22-induced oxidative burst than the wild type, and qPCR confirmed that AtGPXs contribute significantly to glufosinate ammonium stress responses. Evolutionary analysis found high sequence similarity between ApGPX4 and AT1G63460, as well as ApGPX3 and AT4G11600. Also, ApGPX3 and AT4G11600 shared similar expression patterns under glufosinate ammonium stress. This research presents the first gene family study in A. palmeri and provides foundational insights for future studies in this economically critical species. Our findings establish a framework for mitigating A. palmeri’s impact on crop production and exploring ApGPXs in developing herbicide- and stress-tolerant cultivars. Full article

Background: Although Ti-Fu-Kang (TFK) decoction has been clinically used for fatigue management, the systematic understanding of its mechanisms, particularly against central fatigue, remains largely unknown. This study is the first to employ an integrative approach of network pharmacology and metabolomics to explore the mechanisms of TFK against central fatigue. Methods: The central fatigue rat model was established using the modified multiple platform method in conjunction with alternate-day fasting. Behavioral alterations were evaluated through six behavioral tests, while brain injury was assessed through HE and Nissl staining. Serum metabolic indicators were analyzed to identify fatigue-related metabolic disturbances. Western blot analysis was used to assess the protein phosphorylation level of PI3K and AKT1. Oxidative stress was assessed by measuring superoxide dismutase, malondialdehyde, and glutathione peroxidase activities. Network pharmacology and serum metabolomics investigated the molecular mechanisms and metabolic pathways. Results: TFK significantly ameliorated behavioral abnormalities and brain pathological damage in central fatigue model rats. Network pharmacology analysis and in vivo experiment revealed that TFK may mediate biological processes such as oxidative stress and neuron death via the PI3K-AKT signaling pathway. Moreover, analysis of serum fatigue-related metabolic indicators indicated that TFK significantly modulated metabolic disruptions by elevating the levels of glucose, liver glycogen, and muscle glycogen and reducing the levels of alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, creatine kinase, lactate, and lactate dehydrogenase in central fatigue rats. Serum metabolomics analysis revealed that TFK ameliorates central fatigue by modulating amino acid metabolism, specifically by altering the levels of leucine and L-tryptophan, which subsequently contributes to the restoration of 5-hydroxytryptamine and dopamine homeostasis. Conclusions: This study elucidates the potential therapeutic mechanism of TKF in alleviating central fatigue, providing a scientific and theoretical basis for broader application and development of TFK. Full article

Cryptotanshinone (CPT), the main active compound of Salvia miltiorrhiza, is known for its anti-inflammatory, antioxidative, and antifibrotic effects. In this study, the hepatoprotective effect and mechanisms of CPT were explored using transcriptome and network pharmacology. A carbon tetrachloride-induced acute liver injury (ALI) mouse model was established. The anti-ALI effects of different doses of CPT were evaluated by analysis of biochemical indicators, histopathological staining, and immunohistochemical analysis. Combining network pharmacology with transcriptomic analysis revealed therapeutic targets, which were subsequently validated through polymerase chain reaction and Western blotting. CPT (40 mg/kg) treatment significantly reduced the levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, tumor necrosis factor-α, interleukin-6, and interleukin-1β in model mice and regulated oxidative stress indicators, including malonaldehyde, superoxide dismutase, glutathione, and catalase. MCP-1 protein expression in the liver was inhibited by treatment with CPT. Network pharmacology revealed 72 core targets involved in the treatment of ALI by CPT. By combining transcriptomic data from liver tissue, three key targets—TNF-α, TLR9, and ADORA2B—were identified, along with the TLR, IL-17, and TNF signaling pathways. Furthermore, PCR and Western blot assays revealed that CPT significantly decreased TNF-α, TLR9, and ADORA2B expression levels in the livers of ALI mice. In conclusion, the hepatoprotective effects of CPT may be related to the suppression of TNF-α-, TLR9-, and ADORA2B-mediated inflammation, oxidative stress, and apoptosis. These results provide a foundation for the development of CPT as a potential therapeutic agent for ALI. Full article

The 60 kg/m U75V rail serves as the predominant rail type within China’s high-speed rail network. This study comprehensively evaluates the fatigue behavior of U75V rails through experimental investigations encompassing monotonic tensile testing, high-cycle fatigue characterization, and fatigue crack propagation analysis. All specimens were extracted from standardized 60 kg/m high-speed rail sections to ensure material consistency. Firstly, monotonic tensile tests were conducted to determine the fundamental mechanical properties of the U75V rail. Secondly, uniaxial tension–compression fatigue tests were conducted to establish the S-N and P-S-N relationships of the U75V rail. Lastly, fatigue crack propagation analysis was carried out on three compact tension specimens under three incremental loading forces. Monotonic tensile test results demonstrated full compliance of the material’s basic mechanical properties with Chinese national standards. Fatigue crack propagation results indicated that the crack growth rate of the U75V rail was not only related to the stress-intensity range ∆K but was also correlated with the loading force range ∆F due to a typical crack tip shielding effect, i.e., plasticity-induced crack closure effect. The derived fatigue performance parameters and crack growth mechanism provide essential inputs for predictive fatigue life modeling of high-speed rail infrastructure and development of refined finite element models for fatigue analysis. Full article

Natural rock materials, containing micro-cracks and pore defects, significantly alter their mechanical behavior. This study investigated fracture interactions of red sandstone containing double close-round holes (diameter: 10 mm; bridge angle: 30°, 45°, 60°, 90°) using acoustic emission (AE) monitoring and the discrete element simulations method (DEM), which was a novel methodology for revealing dynamic failure mechanisms. The uniaxial compression tests showed that hole geometry critically controlled failure modes: specimens with 0° bridge exhibited elastic–brittle failure with intense AE energy releases and large fractures, while 45° arrangements displayed elastic–plastic behaviors with stable AE signal responses until collapse. The quantitative AE analysis revealed that the fracture-type coefficient k had a distinct temporal clustering characteristic, demonstrating the spatiotemporal synchronization of tensile and shear crack initiation and propagation. Furthermore, numerical simulations identified a critical stress redistribution phenomenon, that axial compressive force chains concentrated along the loading axis, forming continuous longitudinal compression zones, while radial tensile dispersion dominated hole peripheries. Crucially, specimens with 45° and 90° bridges induced prominently symmetric tensile fractures (85° to horizontal direction) and shear-dominated failure near junctions. These findings can advance damage prediction in discontinuous geological media and offer direct insights for optimizing excavation sequences and support design in cavern engineering. Full article

Reservoir landslides undergo saturated–unsaturated transitions under hydrological variations. Matric suction significantly influences slip-zone soil strength. Existing studies lack analysis of suction–rate–strength coupling, while Amontons’ model fails for cohesive soils. This study investigated Huangtupo landslide slip-zone soil in the upper reaches of the Yangtze River using pressure plate and saturated salt solution methods to determine the soil–water characteristic curve. Suction-controlled ring shear tests were conducted under three matric suction levels ($\Psi$ = 0, 200, and 700 kPa) across net normal stresses (${\sigma }_{net}$ = 100–800 kPa) and shear rates ($\dot{\gamma }$ = 0.05–200 mm/min). Key findings revealed the following: (1) significant suction–rate coupling effects were shown, with 700 kPa suction yielding 30% higher residual strength than saturated conditions, validating matric suction’s role in enhancing effective stress and particle contact strength; (2) residual cohesion showed strong logarithmic correlation with shear rate, with the fastest growth below 10 mm/min, while the residual friction angle varied minimally (0.68°), contributing little to overall strength; (3) a bivariate model relating residual cohesion to $\dot{\gamma }$ and $\Psi$ was established, overcoming traditional single-factor limitations. The study demonstrates that dual-parameter Coulomb modeling effectively captures multi-field coupling mechanisms in unsaturated slip-zone soils, providing theoretical foundations for landslide deformation prediction and engineering design under dynamic hydrological conditions. Full article

Ischemic stroke is a leading cause of disability worldwide, often triggered by atherothrombotic or embolic events. A growing body of evidence highlights the role of neuroinflammation as a central mechanism in post-stroke damage, influenced by modifiable systemic risk factors. Emerging evidence suggests that oxidative stress mediates the impact of several modifiable risk factors by activating redox-sensitive pathways (such as NF-κB), impairing nitric oxide bioavailability, and promoting matrix metalloproteinase activity that disrupts vascular integrity and contributes to ischemic injury. In this context, our meta-analysis examined major modifiable risk factors for ischemic stroke, with a particular focus on their shared ability to promote oxidative stress and neuroinflammatory cascades. By emphasizing these redox-dependent mechanisms, our work supports the biological plausibility of exploring antioxidant strategies as complementary approaches to mitigate stroke risk. Hypertension, diabetes, dyslipidemia, smoking, atrial fibrillation, and transient ischemic attacks all contribute to oxidative damage through mechanisms such as endothelial dysfunction, vascular inflammation, and excessive free radical exposure. We searched PubMed, PubMed Central, Web of Science, and Scopus for observational studies published within the last five years, identifying 23 studies (691,524 participants) meeting eligibility criteria. Using a random-effects model, we found significant associations between stroke risk and hypertension (OR = 1.58, 95% CI: 1.28–1.94), smoking (OR = 1.61, 95% CI: 1.13–2.28), type 2 diabetes (OR = 1.53, 95% CI: 1.29–1.81), atrial fibrillation (OR = 1.88, 95% CI: 1.28–2.75), and prior transient ischemic attack (OR = 1.62, 95% CI: 1.24–2.11). These risk factors are known to contribute to systemic inflammation, potentially exacerbating neuroinflammatory cascades post-stroke. Despite limitations such as heterogeneity and low certainty of evidence, our findings reinforce the relevance of targeting inflammation-driven risk factors in stroke prevention strategies and future research. Full article

This research explored the connections between Work Support, Satisfaction with Life, and experienced stress among workers from the automotive sector, with a focus on the indirect influence of job support in the relationship between satisfaction with life and perceived stress using a cross-sectional design. The sample comprised 672 employees (52.98% females). Most participants were aged between 30 and 39 years old (33.48%) or between 40 and 49 years old (29.46%). The primary analysis indicated that Work Support had a partial effect on the connection between Satisfaction with Life and Perceived Stress. Satisfaction with Life was found to directly predict Perceived Stress (B = −0.210, p < 0.001), and there was also a significant indirect effect of Work Support (B = −0.036, 95% CI: −0.051, −0.020). Taken in combination, these results provide several contributions to our comprehension of the mechanisms connecting these constructs, particularly in the car industry. Although Satisfaction with Life showed direct links on Perceived Stress, a significant indirect association via Work Support indicates that a portion of these links are influenced by this route, with potential implications for occupational health. Full article

Background and Objectives: Chronic Obstructive Pulmonary Disease (COPD) is characterized by chronic inflammation and an imbalance between oxidative and antioxidative mechanisms. The aim of this study was to investigate oxidative balance and dynamic thiol/disulfide homeostasis in patients with COPD. Materials and Methods: A total of 68 participants, including 34 COPD patients and 34 healthy controls, were enrolled. Demographic characteristics, smoking status, comorbidities, inflammatory and biochemical parameters, and oxidative stress (OS) markers were recorded. Pulmonary function tests were performed, and COPD patients were classified according to GOLD stages. Correlation, ROC, and multivariate logistic regression analyses were conducted to evaluate the relationships between OS, disease severity, and potential confounders. Results: Among all participants, smoking and comorbidities were significantly more frequent in COPD patients compared to controls. COPD was associated with increased inflammatory and OS markers, characterized by reduced total and native thiol and total antioxidant status (TAS) levels, alongside elevated disulfide, total oxidant status (TOS), and oxidative stress index (OSI). ROC analysis showed strong diagnostic accuracy for thiol parameters, particularly total and native thiol. Thiol depletion and elevated OS were more pronounced with advancing GOLD stage. In multivariate analysis, smoking status was independently associated with COPD. Conclusions: Thiol/disulfide imbalance and OS are evident in COPD, suggesting potential clinical relevance for disease evaluation. However, larger studies are needed to confirm their role as reliable biomarkers or therapeutic targets. Full article

The pressure arch effect limits the influence range of excavation on the surrounding rock, reduces the geological pressure on underground structures, and serves as an important indicator for evaluating the stability of underground engineering. By accounting for the energy transfer process in surrounding rock during the tunnel-induced pressure arch formation, this paper proposes a novel approach for determining the range of the pressure arch around tunnels—the energy density difference (EDD) method. Numerical analysis is conducted to evaluate the effects of tunnel span, internal friction angle, and lateral pressure coefficient on post-excavation energy density fields and pressure arch zones in tunnels. Comparative studies with three existing approaches confirm the EDD method’s efficacy in identifying the arch zones of tunnel-surrounding rock. Critically, the proposed approach addresses the controversy regarding the determination of the deviation degree of principal stress vectors and provides a physically meaningful interpretation of the formation and evolution mechanisms of pressure arches. Full article

Proximal humerus fractures are frequent injuries that often require internal fixation. Conventional metallic plates, however, present significant drawbacks such as corrosion, secondary removal surgeries, and adverse reactions in patients with metal hypersensitivity. This study evaluates biocomposite plates fabricated from polylactic acid (PLA) and polyvinyl alcohol (PVA), reinforced with hydroxyapatite (HA) derived from sugar industry by-products (BCF) at 10% and 20% concentrations. These composites are compatible with both injection molding and 3D printing, enabling the design of patient-specific implants. Characterization by SEM, FTIR, XRD, and DSC confirmed that BCF incorporation enhances strength, stiffness, osteoconductivity, and biocompatibility. Mechanical testing showed that PVA/BCF exhibited greater tensile strength and stiffness, suggesting suitability for load-bearing applications, though their water solubility restricts use in humid environments and prevents filament-based 3D printing. PLA/BCF composites demonstrated better processability, favorable mechanical performance, and compatibility with both manufacturing routes. Finite element analysis highlighted the importance of plate–humerus contact in stress distribution and fixation stability. Compared with non-biodegradable thermoplastics such as PEI and PEEK, PLA/BCF and PVA/BCF offer the additional advantage of controlled biodegradation, reducing the need for secondary surgeries. Cell viability assays confirmed cytocompatibility, with optimal outcomes at 10% BCF in PVA and 20% in PLA. These results position PLA/BCF and PVA/BCF as sustainable, patient-tailored alternatives to metallic implants, combining adequate mechanical support with bone regeneration potential. Full article

Electrical cable insulation, mainly composed of polymeric materials, progressively deteriorates under thermal, electrical, mechanical, and environmental stress factors. This degradation reduces dielectric strength, thermal stability, and mechanical integrity, thereby increasing susceptibility to failure modes such as partial discharges, arcing, and surface tracking—recognized precursors of fire ignition. This review consolidates current knowledge on the degradation pathways of cable insulation and their direct link to fire hazards. Emphasis is placed on mechanisms including thermal-oxidative aging, electrical treeing, surface tracking, and thermal conductivity decline, as well as the complex interactions introduced by flame-retardant additives. A bibliometric analysis of 217 publications reveals strong clustering around material degradation phenomena, while underlining underexplored areas such as ignition mechanisms, diagnostic monitoring, and system-level fire modeling. Comparative experimental findings further demonstrate how insulation aging modifies ignition thresholds, heat release rates, and smoke toxicity. By integrating perspectives from materials science, electrical engineering, and fire dynamics, this review establishes the nexus between aging mechanisms and fire hazards. Full article

To evaluate the creep and fatigue fracture lives of structural acrylic spliced components fabricated via bulk polymerization, and to elucidate the associated fracture mechanisms, this study conducted creep and fatigue tests on spliced coupons annealed at 85 °C and 65 °C, as well as base material coupons. The experimental life data were fitted using log-log linear regression models. Based on statistical analysis, a simple yet robust statistical framework was established for life prediction, featuring three design curves: 97.7% survival curves, improved 95% confidence interval lower bounds, and one-sided tolerance curves. Fractographic examination using scanning electron microscopy (SEM) was performed to characterize macroscopic failure modes. The results indicate distinct threshold behavior between stress levels and both creep and fatigue life. The creep threshold stresses are 25 MPa for the base material, 29 MPa for the spliced coupons annealed at 85 °C, and 17 MPa for the spliced coupons annealed at 65 °C. Corresponding fatigue threshold stress amplitudes are 21 MPa, 22 MPa, and 31 MPa, respectively. Failure in the base material is primarily initiated by randomly distributed internal defects, whereas failure in the spliced coupons is mainly caused by defects within the seam or interfacial tearing. Full article