Search Results (16,800)

Return-type cable suspension bridges transfer the main-cable force to the anchorage predominantly in the horizontal direction, which may induce coupled sliding–overturning instability of the anchorage–foundation system. This study examines the stability of return-type cable gravity anchorage using the composite anchorage of the Jixin Expressway Yellow River Three Gorges Bridge as the prototype. A 1:100 laboratory specimen was designed based on similarity theory and tested under incremental loading until failure. Four configurations were considered by combining two embedment ratios (1/4 and 1/2) with two base types (flat-base and shear-keyed). Horizontal displacement, overturning angle, interface contact stress, and foundation strain were monitored throughout loading. Because the return-type cable transmits a predominantly horizontal force, the anchorage–foundation contact stress exhibits pronounced asymmetry between the toe and heel regions, and this stress asymmetry governs the coupled sliding–overturning instability mode. The shallow flat-base case exhibited a distinct displacement and contact stress jump at high load levels, followed by rapid rotation, indicating slip–tilt coupled instability. Increasing embedment improved confinement and delayed the onset of nonlinear deformation, but the flat-base configuration still showed pronounced toe stress concentration. By contrast, the shear-keyed base mobilized cooperative bearing of the surrounding foundation, producing smoother stress–strain evolution and higher ultimate capacity. Moreover, the shear-keyed base mitigates the stress asymmetry at the anchorage–foundation interface, leading to a more symmetric distribution of contact pressure and improved overall stability. Three-dimensional finite-element simulations reproduced the measured trends in displacement, stress concentration near the toe, and strain development, providing independent verification. The results clarify the dominant instability mechanism of return-type cable gravity anchors and offer design implications for embedment depth and shear-keyed base detailing. Full article

Gravel particles are widely developed and randomly distributed in deep reservoirs of the Tarim Oilfield, western China. The mechanical behavior of conglomerate, the main component of the gravel layer, under varying confining pressure and different gravel content, remains poorly understood, especially in terms of the microscopic aspect, which limits the analysis of the variation patterns of underground engineering parameters. This study conducts triaxial compression tests on outcrop specimens from various stress levels to analyze the effects of stress state and stress differences on the mechanical parameters and failure modes. After that, a kind of numerical modeling method based on the discrete element method (DEM) is proposed, which considers the random distribution of gravel particles, to study the microscopic observation of mechanical characteristics and crack propagation of conglomerate under different stress state conditions. The experimental and numerical simulation results indicate that the horizontal strain before failure remains nearly constant in the axial direction while increasing linearly for the horizontal stress. And, it was observed that the volumetric failure was accompanied by gravel fragmentation, sliding, and falling. Numerical simulations reveal that cementation strength and gravel content significantly influence mechanical properties and failure modes, which are the main factors. This study provides some useful references for further understanding of the mechanical behavior and failure mechanisms of rocks in the gravel layer, in particular, the numerical modeling method for heterogeneous materials. Full article

Gingival recession is commonly linked to alveolar bone dehiscence, inflammatory burden, traumatic brushing, or excessive orthodontic forces. However, recession is also observed in some patients despite apparently mild or “biologically acceptable” loading, particularly in thin periodontal phenotypes. Here, we propose the Gingival Creep Failure Theory, a hypothesis-driven conceptual framework in which gingival soft tissues undergo time-dependent viscoelastic deformation (creep) under sustained or repetitive tensile microstrain. Over time, accumulated deformation and microstructural fatigue may reduce recoil capacity and shift the gingival margin apically once tissue-level tolerance is exceeded. Gingival connective tissue is modeled as a fiber-reinforced, fluid-rich viscoelastic composite whose response depends on collagen architecture, cross-linking, proteoglycan-mediated hydration, and vascular support. In thin phenotypes characterized by reduced connective tissue volume and altered extracellular matrix (ECM) organization, creep progression is hypothesized to accelerate, lowering the threshold at which fatigue-related microdamage translates into clinically detectable marginal migration. Evidence from collagenous connective tissue biomechanics supports the plausibility that sub-failure sustained or cyclic loading can produce cumulative deformation and incomplete recovery; however, direct creep–fatigue data for human gingiva remain limited, underscoring the need for targeted validation studies. This hypothesis integrates soft tissue mechanics with periodontal phenotype biology and orthodontic loading patterns and proposes creep and microstructural fatigue as plausible time-dependent contributors to gingival recession in susceptible phenotypes. Because direct in vivo gingival strain and creep–fatigue measurements remain limited, the model should be interpreted as hypothesis-generating and in need of targeted clinical and experimental validation. Full article

Quorum Quenching (QQ) is a mechanism that disrupts Quorum Sensing (QS) signaling systems, which regulate gene expression based on bacterial population density. Many fish pathogens, such as Aeromonas, utilize QS systems to regulate the expression of their virulence factors. Disrupting these systems using QQ is a promising approach for infection control in aquaculture and may provide a safe alternative to antibiotics. Therefore, identifying microorganisms with QQ activity is a relevant task in agricultural microbiology and veterinary medicine. This study examines the identification of isolates with QQ activity in the microbial community of perch and assesses their probiotic potential for the prevention of aeromonosis. In this study, we isolated 32 strains of microorganisms capable of degrading N-acylhomoserine lactone (AHL), six of which exhibited stable QQ activity. Five strains were found to belong to the genus Rhodococcus, and one strain to the genus Exiguobacterium. The selected strains were tested for the enzymatic/non-enzymatic and intra-/extracellular QQ activity, pathogen growth inhibition, biofilm formation, and hemolytic activity, as well as growth ability under various environmental conditions (salinity, pH, bile acids, and temperature). Based on the results of these tests, the R. erythropolis PFS1.20 strain was selected as the most promising probiotic. The genomic analysis revealed that the studied strain contains genes encoding QQ enzymes, siderophore biosynthesis clusters, osmoprotectors, and compounds with antimicrobial properties. These results indicate the high probiotic potential of the R. erythropolis PFS1.20. Full article

Coal gangue is one of the most abundant solid wastes generated during coal mining. The use of coal gangue for underground backfilling is widely recognized as an effective approach to reducing waste accumulation and promoting sustainable utilization. To further investigate the bearing and deformation behavior of underground gangue filling materials, combined with the underground occurrence conditions of crushed gangue in goaf, a self-designed loading apparatus for crushed gangue was employed to perform lateral compression experiments on crushed gangue. The compaction deformation, fractal dimension, and acoustic emission evolution characteristics of crushed gangue under the influence of lithology, water content state, particle size distribution, and axial pressure were analyzed. The results indicate that higher rock strength, lower moisture content, smaller particle size range, and lower axial pressure significantly enhance the bearing capacity and reduce axial strain. The fractal dimension increases with decreasing rock strength, increasing moisture content, and increasing axial pressure, reflecting intensified particle fragmentation. The acoustic emission response exhibits three different stages, corresponding to void compaction, void filling, and structural adjustment. Axial pressure has been identified as the main factor controlling acoustic emission energy release, while water content significantly suppresses acoustic emission energy and event frequency. The key roles of particle sliding, rotation, and torque-driven rearrangement in controlling overall deformation were elucidated. These findings provide theoretical support for the mechanical behavior of gangue filling in the goaf and the sustainable disposal and resource utilization of mining waste. Full article

In-well hydraulic fracture monitoring based on joint low-frequency distributed acoustic sensing (LF-DAS)/distributed temperature sensing (DTS) enables the acquisition of optical fiber mechanical strain data, which reflect fracture propagation and rock deformation during hydraulic fracturing. This paper presents an analytical method to interpret the mechanical strain profile measured by in-well LF-DAS/DTS during the fracturing process based on strain transfer theory and the Sneddon solution for fracture propagation. The analytical method is validated by a numerical model that simulates the strain field induced by fracture propagation. The sensitivity of the fiber strain to key factors, such as fracture geometry parameters and gauge length, is analyzed. The results indicate that compressive strain in the formation adjacent to the propagating fracture remains observable from the mechanical strain profile under the low fiber lag parameter condition. The presented method is applied to analyze the mechanical strain profile measured from a fractured horizontal well. Considering the reactivation of the pre-existing fracture, the location of the fractures is identified, and the fractures’ geometric parameters are inverted. This study provides a quantitative evaluation method for fracture geometry characterization based on joint LF-DAS/DTS fracturing monitoring. Full article

This study aims to examine the impact of the COVID-19 pandemic on the hospitality sector in Greece during the COVID-19 period. To this end, questionnaires were distributed in 320 enterprises operating throughout Greece exclusively in the hospitality industry. Structural equation modeling (SEM) was employed for analyzing data. The results reveal a structured transmission pathway: Business Survival Anxiety and Psychological Distress intensify Financial Strain; financial pressure constrains Strategic Capability; and diminished strategic flexibility shapes firms’ evaluation of the crisis’s overall impact. Financial Strain emerges as the central mediating mechanism, bridging managerial perceptions and organisational outcomes. These findings confirm that crisis impact is embedded in firm-level dynamics, where psychological pressures, resource constraints, and strategic contraction interact systematically. Ultimately, the study shows that the severity of the pandemic was not assessed solely in terms of immediate revenue loss, but in relation to the erosion of strategic capacity—innovation, investment potential, and long-term competitiveness. Resilience in tourism therefore depends on the alignment between psychological stability, financial robustness, and strategic adaptability. Full article

Plant pathogens pose a severe threat to global agricultural production, and their pathogenicity is closely linked to the biosynthesis of secondary metabolites. Basidiomycete within the family Ustilaginaceae represent significant plant pathogens, among which Ustilago maydis, as a model species, has been extensively studied for its secondary metabolites. However, the biosynthetic potential of other species within this family remains poorly understood. In this study, we conducted whole-genome bioinformatic analyses of 16 Ustilaginaceae species, including U. maydis, to systematically identify the distribution of biosynthetic gene clusters (BGCs), core gene domain compositions, and interspecies similarities. A total of 181 predicted BGCs were identified, averaging approximately 11 per species. BGCs for mannosylerythritol lipids (MELs), siderophores, and itaconic acid, as well as the melanin-associated genes pks1 and pks2, were widely distributed across most species. Conversely, an additional melanin biosynthetic gene cluster was found exclusively in U. maydis strain 521, indicating species-specific occurrence. Furthermore, this study identified a novel class of polyketide synthase (PKS) gene clusters with uncharacterized functions across 15 species, exhibiting high sequence and structural conservation between species. These findings reveal the rich metabolic diversity and species-specific biosynthetic potential of Ustilaginaceae, and by using U. maydis as a reference model, we highlight several BGCs (e.g., for MELs, siderophores, itaconic acid, and melanin) that are known to contribute to virulence or pathogenicity in plant hosts. This provides new insights into their pathogenic mechanisms. Full article

Arsenic-contaminated groundwater is a major environmental concern, particularly in northern Argentina. Here, Microbacterium oxydans AE038-20, isolated from arsenic-rich groundwater, was investigated to elucidate its tolerance and transformation capacity. Growth assays showed that the strain tolerates inorganic arsenic [As(III), As(V)] and methylarsenite [MAs(III)] without significant inhibition. Speciation analyses revealed progressive oxidation of As(III) to As(V), reaching near-complete conversion after 10 days. Similarly, MAs(III) was fully oxidized to MAs(V). Genome sequencing identified ars-related determinants, including arsR, arsC, putative arsenite efflux systems, and arsP, supporting detoxification via arsenate reduction and arsenite efflux. Proteomic analyses confirmed the expression of proteins related to arsenic resistance, oxidative stress response, and metal transport. However, no canonical arsenite oxidases were detected at either the genomic or proteomic level. Despite this, M. oxydans AE038-20 exhibited clear arsenic oxidation activity. The detection of pigment-associated proteins and in vitro oxidation assays suggest an alternative mechanism potentially mediated by redox-active pigments. These findings highlight an alternative pathway for arsenic transformation in environmental bacteria. Full article

Fermented dairy products with probiotic and functional properties are a promising matrix for modulation of the human microbiome. The functionality of such products will depend not only on the technological properties of the lactic acid bacteria included in the starter culture but also on the combined effects of metabolites, enzymatic activity, stress tolerance, and strain-specific adaptation mechanisms. The aim of this work was to conduct a comprehensive analysis of Lactobacillus strains to facilitate the design of microbial consortia for the development of fermented products with diverse functional properties. Twenty Lactobacillus strains from different species were investigated using microbiological, physicochemical, and biochemical methods to evaluate antagonistic activity against opportunistic microorganisms and to assess changes in amino acid and organic acid profiles, vitamin content, fatty acid composition, and enzymatic activity. Additionally, proteomic analysis was performed to create a matrix of functional complementarity of the studied strains, representing proteins associated with antimicrobial activity, bacteriocin transport, resistance to oxidative stress, surface structure formation, and adhesion. It was shown that the studied strains exhibit pronounced functional heterogeneity, demonstrating the feasibility of scientifically based selection of strains to create next-generation fermented dairy products with predictable properties. Full article

Phelipanche aegyptiaca is a root parasitic weed that causes severe yield losses in tomato production. Current control methods are constrained by limited efficacy and environmental concerns. Although biocontrol microbes and amino acids have each been reported to suppress broomrape parasitism individually, their synergistic effects and underlying molecular mechanisms remain largely unexplored. This study evaluated the biocontrol performance of Bacillus velezensis strain N35, applied alone or in combination with five amino acids (methionine, isoleucine, valine, histidine, and proline), against P. aegyptiaca parasitism in tomato using pot experiments coupled with transcriptomic profiling of host roots. Both individual and combined treatments significantly reduced the number and fresh weight of P. aegyptiaca parasitic tubercles. Notably, the combinations of methionine + N35 and isoleucine + N35 achieved near-complete suppression of parasitism. Transcriptomic analysis revealed extensive reprogramming of gene expression in tomato roots, with significant enrichment in pathways associated with plant hormone signal transduction, MAPK signaling, phenylpropanoid biosynthesis, and carotenoid biosynthesis. The synergistic treatments coordinately activated ethylene, jasmonic acid, and salicylic acid-mediated signaling, while suppressing auxin and abscisic acid signaling. Moreover, key strigolactone biosynthesis genes (CCD7 and CCD8) were strongly downregulated, and specific genes involved in the biosynthesis of defense-related secondary metabolites were selectively upregulated. Collectively, these findings demonstrate a pronounced synergy between B. velezensis N35 and specific amino acids in suppressing P. aegyptiaca parasitism. This enhanced host resistance is achieved through the coordinated reprogramming of hormonal and metabolic networks, particularly via interference with strigolactone-mediated germination signal secretion. This study provides a theoretical basis for the development of microbe–metabolite synergistic strategies as sustainable and environmentally benign alternatives for broomrape management. Full article

Congenital Long QT Syndrome (LQTS) is a hereditary cardiac channelopathy defined by delayed ventricular repolarization and an elevated risk of life-threatening ventricular arrhythmias. Recent echocardiographic studies using speckle-tracking and strain imaging have identified subtle abnormalities in ventricular and atrial mechanics among LQTS patients, including reduced global longitudinal strain, impaired diastolic function, enlarged left atrial volumes and a consistently negative electromechanical window. These findings challenge the traditional concept of LQTS as solely an electrical disease and support evolving evidence of a subclinical cardiomyopathic phenotype. Left atrial remodeling, although less studied, may represent an underrecognized component of LQTS with potential implications for arrhythmia vulnerability and diastolic dysfunction. This review summarizes current evidence on electromechanical and structural cardiac involvement in congenital LQTS, highlights its diagnostic and clinical implications, and outlines future directions for research in this evolving field. Full article

Diamonds have attracted much attention due to their superior tribological performance. However, there is no unified understanding of the friction and wear mechanism of diamonds under thermal conditions. To address this issue, it is extremely important to explain the wear mechanism of diamonds under thermal conditions. The tribological and thermodynamic properties of diamonds at various temperatures were simulated by molecular dynamics (MD); the tribological mechanism of diamonds at different temperatures was discussed on the atomic scale, and the friction force and coefficients, strain, and stress were analyzed. The radial distribution function (RDF) and mean square displacement (MSD), temperature contour and displacement contour, and the wear mechanism of a diamond under thermal conditions are also discussed. The research results illustrate that with the increase in system temperature, the average friction force and coefficients of diamond gradually increase, and the distribution position of atoms is different at different temperatures. Full article

Stimuli-responsive hydrogels have gained significant attention as one of the most attractive materials for soft robots. Herein, a facile, printable thermo-responsive hydrogel (NL hydrogel) with rapid volume change capability and excellent mechanical properties was developed through the self-assembly of poly(N-isopropylacrylamide) (PNIPAM) and hydrophobic lignin. The lignin and PNIPAM self-assembled into a hierarchical phase-separated structure consisting of lignin-rich dense regions with a bicontinuous morphology and PNIPAM-rich, chain-sparse regions. This unique architecture results in multiscale water channels, enabling an ultrafast dehydration response (expelling 90% of its water within 10 s) and an ultrahigh volume shrinkage of up to 96.4% above its lower critical solution temperature (LCST). The phase separation structure also endows the NL hydrogels with outstanding mechanical properties, achieving tensile stress and strain values exceeding 1 MPa and 500% below the LCST, and approximately 5 MPa and 1500% above the LCST. The responsive speed and mechanical properties of the NL hydrogels surpass those of most reported thermo-responsive hydrogels. The NL hydrogels can be readily printed via direct ink writing into various geometries. The printed NL hydrogels demonstrate thermo-triggered shape morphing, functioning as temperature-controlled actuators with adjustable curvature and as manipulators for capture, wrapping, encapsulation, and switching. Furthermore, the photothermal effect of lignin enables light-controlled actuation of the NL hydrogel. Full article

Type-IV composite overwrapped pressure vessels (COPVs) enable efficient hydrogen storage but experience severe thermal and mechanical loads that threaten structural integrity, necessitating reliable condition monitoring. This work investigates pseudo-elastic shape-memory alloy (SMA) strain gauges as a cost-effective alternative to fiber-optic systems for monitoring COPVs. Their performance was characterized on composite specimens using four-point bending tests. Additionally, a finite element model analyzed surface-strain behavior as a function of COPV geometry parameters and ambient temperature, enabling identification of optimal quarter-bridge measurement configurations. Full article