Search Results (16,810)

Candida albicans is a yeast found in the oral cavity, gastrointestinal tract, and vaginal mucosa. This species is the most prevalent and virulent in conditions such as oral candidiasis. Myrtenol is a bicyclic monoterpene alcohol recognized for its antioxidant and anti-inflammatory attributes. Its primary source is the essential oil extracted from plants of the Myrtaceae family. This study evaluated the effect of (−)-myrtenol on the virulence factors of Candida albicans. Ten clinical isolates of Candida albicans and one reference strain (ATCC 90028) were used in this study. The virulence factors examined included adhesion, morphogenesis, and lipase production. Assays were conducted in the presence and absence of (−)-myrtenol, using a concentration corresponding to the minimum inhibitory concentration (MIC; 256 µg/mL). Results: The compound reduced the adherence of C. albicans to human oral epithelial cells (92.24 vs. 28.69), and reduced filamentation in liquid (3.17 vs. 2.57) and solid media. Furthermore, (−)-myrtenol inhibited lipase activity (0.68 vs. 1.00). Virulence factors expressed by C. albicans contribute to increased infection rates and, consequently, increased morbidity and mortality. The present findings demonstrate that (−)-myrtenol affects virulence-associated phenotypes of C. albicans in vitro. This compound represents a promising candidate for further investigation, particularly in studies addressing its mechanisms of action, safety, and potential applicability. Full article

This study investigates the stress–strain state of rocks subjected to the impact of penetrators with diverse configurations, employing numerical simulations in the ANSYS Workbench Static Structural module. The research focuses on the interaction between roller cone drill bit teeth and rock formations during blast hole drilling. Through finite element modeling using a linear elastic constitutive model, the influence of penetrator geometry, position relative to borehole walls, angle of attack, and distance to open surfaces on rock fracture parameters is analyzed. Key quantitative findings include: the relative breaking force near the borehole wall reaches 2.8 for soft rocks (siltstones) with a 10 mm tooth diameter, and decreases to approximately 1.0 at a distance of 1.5d from the wall; the optimal angle of attack ranges from 60° to 90° depending on rock hardness; and the proximity to a free surface reduces fracture resistance to as low as 0.23 of the baseline value. Six sets of parabolic regression equations (R² > 0.95) are derived for relative breaking forces across three rock hardness groups and two tooth diameters. Optimal parameters for tooth placement, borehole bottom shapes, and operational conditions are proposed. Implementation of the recommended parameters is estimated to increase drilling efficiency by 10–20% and extend tool service life by 15–30%. The findings provide a scientific foundation for designing advanced roller cone drill bits suitable for rocks with Protodyakonov hardness indices ranging from f = 5 to f = 18. Full article

The present study aims to investigate the interaction between different martensite variants (MVs) activated in an AISI 304 austenite steel subjected to tension. Particular attention is paid to the abnormal morphologies of martensite–martensite interaction (MMI) and their possible formation mechanisms during deformation-induced martensitic transformation. The abnormal morphologies of martensite–martensite interaction (MMI) were characterized. It was revealed that MMI was accompanied by the formation of extremely incoherent interfaces. MVs can continue to grow upon impinging on each other, resulting in the morphology where one MV is crossed or totally surrounded by another. The present findings provide new insight into martensite growth behavior and variant interaction and may contribute to a better understanding of the microstructural origin of the excellent strain-hardening capability and mechanical performance of metastable austenitic steels. Full article

Food-grade microorganisms utilize core cofactors, such as nicotinamide adenine dinucleotide (NAD) and its phosphate form (NADP), to mediate redox reactions and regulate energy metabolism homeostasis as well as biosynthesis of functional components. In metabolic engineering, perturbation of the NAD(P)⁺/NAD(P)H network may significantly disrupt intracellular redox homeostasis, leading to impaired strain growth and limited synthesis of targeted functional products. This review systematically examines the latest research progress in the field of food-grade microbial cofactor engineering, focusing on the key mechanisms and synergistic pathways of core strategies, such as metabolic flux optimization and cofactor regeneration systems, in maintaining cellular redox homeostasis and enhancing the biosynthesis of functional ingredients. Future research should focus on exploring the potential for integrating multi-omics approaches and intelligent control technologies, proposing innovative approaches to address the challenges of industrialized production, and providing theoretical support for food biomanufacturing. Full article

Island reef road construction faces a complex marine service environment characterized by high salinity and high humidity. Meanwhile, rapid construction and prompt subgrade repair are urgently required, creating a strong demand for novel calcareous-sand-based stabilization materials that combine excellent mechanical performance with resistance to seawater erosion. To this end, this study developed an early-strength cemented calcareous-sand reinforcement material for road base construction. Sulfoaluminate cement (SAC) and ferrite-aluminate cement (FAC), both featuring rapid setting/early strength development and superior corrosion resistance, were used to cement calcareous sand (CS) and to investigate its mechanical and microstructural characteristics under different water environments. Unconfined compressive strength tests (UCS) showed that SC-CS and FC-CS could meet subgrade requirements at 1 d and 7 d, with SC-CS and FC-CS reaching 3.12 MPa and 3.44 MPa at 1 d, and 3.26 MPa and 3.67 MPa at 7 d, respectively, under seawater SS conditions. Seawater mixing and immersion were found to promote the early strength and stiffness development of both SC-CS and FC-CS, with a more pronounced effect observed for FC-CS. Based on experimental results, a damage model for the stabilized specimens was established with a fitting accuracy of R² > 0.97. This constitutive model accurately describes the stress–strain relationship of the material and quantitatively characterizes its damage evolution. Microscopic XRD and SEM analyses indicated that the main hydration product in freshwater-cured specimens was ettringite, and the interparticle connection of CS was dominated by bridging through rod-like ettringite. In contrast, under seawater conditions, the ettringite content decreased, while hydrotalcite and calcium aluminate hydrate increased, forming massive and lamellar bridging products. Compared with SC-CS, the bridging structure in FC-CS was denser. Moreover, the compactness of the bridging structure not only affected its mechanical properties but also governed the movement mode of CS particles, thereby influencing the damage evolution and failure mode of the specimens. The findings provide theoretical support for the construction needs of island road. Full article

Toxoplasma gondii, an obligate intracellular protozoan infecting approximately one-third of the global population, poses a significant yet underappreciated threat to reproductive health in both sexes. Although this parasite has long been linked to birth defects caused by infection during pregnancy, new research shows that it also reduces fertility in both sexes through different but related mechanisms. This review synthesizes knowledge on T. gondii-induced reproductive pathology across females and males, examining shared mechanistic themes while respecting tissue-specific differences, and evaluates emerging therapeutic strategies. In females, the parasite establishes persistent uterine reservoirs, triggers decidual immune dysregulation characterized by NK cell cytotoxicity, M1 macrophage polarization, Treg apoptosis, and inflammasome-mediated pyroptosis, while disrupting estrogen and progesterone signaling through both host receptor modulation and intrinsic parasite steroidogenic enzymes (TgCYP450mt, TgMAPR, Tg-HSD). In males, T. gondii breaches the blood–testis barrier, induces germ cell and Leydig cell apoptosis via ER stress and caspase pathways, impairs sperm quality parameters across acute and chronic infection, and disrupts the hypothalamic–pituitary–gonadal axis. Conserved molecular mechanisms—including NLRP3 inflammasome activation, PERK/eIF2α/ATF4/CHOP-mediated ER stress, and oxidative stress—operate in both reproductive tissues. The parasite’s intrinsic steroidogenic capability and bidirectional hormonal manipulation represent a paradigm shift in understanding host–parasite interactions. Conventional antiparasitics face limitations due to poor reproductive sanctuary penetration. Immunomodulatory approaches targeting Trem2, Tim-3, and the NLRP3 inflammasome show promise, along with natural products including Inonotus obliquus polysaccharide and ginseng polysaccharide. Nanomedicine platforms and mRNA vaccine candidates offer new directions for overcoming tissue barrier limitations. Toxoplasma gondii represents a fundamental threat to fertility and pregnancy outcomes rather than merely a risk for congenital infection. Integrated therapeutic strategies addressing direct parasitism, immunopathology, and endocrine disruption are needed. Longitudinal cohort studies, strain-specific mechanistic comparisons, and clinical trials of immunomodulatory adjuncts are urgently required. Full article

Airfoil fin Printed Circuit Heat Exchangers (PCHEs) offer significant advantages in reducing flow resistance, promoting turbulence, and enhancing heat transfer performance due to their discrete fin configuration. However, compared with conventional continuous-channel structures, the geometric discontinuities and sharp trailing edges introduced by discrete fins tend to induce severe stress concentration at the fin roots, resulting in a more complex structural response. In this study, a PCHE core with NACA0020 airfoil fins is investigated. Finite element analysis combined with a sequential one-way thermo-structural coupling approach is conducted to characterize the fins’ stress and deformation behavior under high temperature and pressure. The plate region is evaluated based on the linear elastic stress criteria specified in ASME Boiler and Pressure Vessel Code Section III, while localized yielding regions such as the fin roots are assessed using an equivalent plastic strain indicator. Results indicate that the structural response of the PCHE core is dominated by pressure loading under the investigated operating conditions with ΔT = 18 °C and ΔP = 12.05 MPa, whereas thermal stress caused by constrained thermal expansion mainly modifies local stress distributions and has a limited effect on global deformation. Owing to the discontinuous support provided by discrete airfoil fins, the fin roots act as the primary load-transfer path and sustain higher stress levels. The maximum von Mises stress is observed at the trailing edge of the fin root on the high-pressure side, while the largest deformation occurs in the unsupported plate region and is governed by bending. Parametric analysis indicates that, within the investigated parameter range, a fully staggered fin arrangement promotes more uniform load distribution and exhibits the most favorable structural response. In contrast, increasing the fin chord length and relative thickness reduces the overall load-carrying capacity of the core. Finally, a power-law predictive correlation for the maximum total plate deformation was developed, showing that the parameter influence on plate structural response follows the order horizontal pitch (L_h) > vertical pitch (L_v) > channel etching depth (L_e) > staggered pitch (L_s). In contrast, normalized sensitivity analysis of the maximum fin-root von Mises stress shows the order staggered pitch (L_s) > horizontal pitch (L_h) > vertical pitch (L_v) > channel etching depth (L_e), indicating that global plate deformation and local fin-root response are governed by different structural mechanisms. Full article

In this study, six serpentine resistive strain sensors are manufactured on two cantilevers made of FR-4 (Flame Retardant 4) with dimensions of 25 mm × 140 mm. Three strain sensors are printed on each substrate using particle-free EI 615 silver ink. The method of fabrication is hybrid in nature and consists of aerosol jet (AJ) printing a layer of conductive material and selectively sintering certain regions before removing the non-sintered material with 1-dodecene solvent. The gauges on one cantilever are coated with a 10 µm dielectric layer using Norland Electronic Adhesives (NEA) 121, which serves as the passivation layer, while the three gauges on the other cantilever are left exposed. The samples are subjected to two standard thermal–mechanical loading conditions: namely, a vibration test according to the MIL-STD-883 method 2007 Cond A and a high-temperature soak test according to the Mil-Std-883 method 1008 Cond B. The reliability of the devices is quantified by assessing the percent change in their resistances and gauge factors (GF) between tests. The percent change is then used to ascribe a reliability metric to the gauges. Full article

Public health suffers from noxious gas emitted by massive beached Sargassum algae. Net-barrages deployed in near-shore seas can contain Sargassum, provided they efficiently resist the additional hydrodynamic pressure induced by the catch. Nowadays, the design and installation of net-barrages are empiric. Structural breaks and anchor and mooring chain drifts can arise. We provide a mechanical model to evaluate stresses and loads on a structure made of fishing nets and buoy moorings. Hydrodynamic uncertainties occur through catches, fouling and sea current amplitudes appearing in lagoons or sheltered bays. This study presents a non-linear four-node finite-element model for continuous elastic membranes undergoing large displacements and small strains. The model relies on the Lagrangian linearly elastic membrane theory, employing the non-linear Green strain tensor and a non-updated hydrodynamic loading. We study forcings fixed a priori on a netting section of barrage that is 50 m long and 1 m high with double layer, e.g., two net-faces. We consider low and moderate current velocities, 0.05 and 0.35 m∙s⁻¹, while assuming specific vertical and horizontal catch pressures. A barrage installed in the reef lagoon at Le François on Martinique Island that is observable by satellite imagery could benefit of the computed net and mooring tensions. Full article

Hospital wastewater represents a critical hotspot for the dissemination of antibiotic resistance genes (ARGs), serving both as an environmental reservoir and a transmission pathway for multidrug-resistant bacteria into receiving ecosystems. The intense antibiotic selective pressure within healthcare facilities promotes the emergence, persistence and amplification of resistant strains, posing substantial risks to public health and environmental integrity. This study aimed to characterize Escherichia coli (E. coli) isolates recovered from hospital wastewater effluents in multiple cities across Gabon, with emphasis on bacterial loads, antimicrobial resistance patterns and associated genetic determinants. Wastewater samples were aseptically collected from sewer outlets of eleven healthcare facilities distributed across five provinces over a 12-week period, structured into two six-week sampling campaigns to capture temporal variability. A total of 158 bacterial isolates were obtained, among which 49 were confirmed as E. coli. Mean concentrations of presumptive E. coli ranged from 7.1 × 10³ to 1.49 × 10⁹ CFU/mL, indicating substantial microbial contamination of hospital effluents. Antimicrobial susceptibility testing using the Kirby–Bauer disk diffusion method against 19 antibiotics revealed that all isolates exhibited multidrug-resistant phenotypes. Resistance rates were particularly high to β-lactams and third-generation cephalosporins, reaching 90–100% in most facilities, reflecting strong selective pressure and widespread circulation of resistance mechanisms in urban aquatic environments. In contrast, carbapenems and amikacin remained comparatively effective, with resistance levels below 40%, suggesting partial preservation of last-resort therapeutic options. The values of the Multiple Antibiotic Resistance Index (MARI) ranged from 0.21 to 0.84, indicating selection pressure on different classes of antibiotics. Phylogenetic analysis showed a predominance of phylogroup A, traditionally considered commensal but increasingly associated with the spread of resistance. Groups B2, D/E and F proved to be the most resistant. These groups showed marked resistance to first-line antibiotics. The blaCTX-M-1 was the most prevalent resistance determinant (66.6%), occurring twice as frequently as blaSHV (33.3%), a finding that confirms the significant circulation of extended-spectrum β-lactamase-producing E. coli. Overall, these findings highlight hospital wastewater as a major reservoir and dissemination source of multidrug-resistant E. coli, underscoring the urgent need for improved wastewater treatment, strengthened antimicrobial stewardship and integrated One Health-based surveillance strategies. Full article

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