Search Results (42,268)

Background: Vulvovaginal candidiasis (VVC) is a significant public health concern characterized by increasing incidence and challenges in treatment. However, most studies investigating Candida spp. virulence factors and antifungal susceptibility predominantly rely on in vitro assays. While these assays are highly reproducible, they do not accurately replicate the complex vaginal microenvironment. To address this limitation, we developed an ex vivo model using porcine vaginal mucosa and a physiologically relevant volume of simulated vaginal fluid (SFV) to better mimic human vaginal conditions. Methods: Biofilm formation and fluconazole activity were assessed using the reference strain Candida albicans ATCC 90028 and two clinical isolates associated with VVC. Results were expressed as colony-forming units (CFU) and directly compared with in vitro assays conducted in Sabouraud dextrose broth (SDB) and SVF. Results: CFU analysis revealed that the ex vivo vaginal mucosa model supported more robust biofilm development, with counts ranging from 6.67 × 10⁷ to 7.20 × 10⁷ CFU/mL, compared to the in vitro SDB assay (3.58 × 10⁷ to 4.5 × 10⁷ CFU/mL). This suggests enhanced fungal growth under tissue-based conditions. Moreover, fluconazole achieved greater biofilm eradication in the ex vivo model (>70%) compared to the in vitro SDB assay (≤34.50%), which may indicate increased antifungal activity within a physiologically relevant environment. Conclusions: The ex vivo vaginal mucosa model offers a physiologically relevant platform for supporting C. albicans biofilm development and serves as a valuable alternative for preclinical screening of antifungal agents. Full article

This paper deals with a boundary control problem for the Darcy–Brinkman–Jeffreys system describing 3D (or 2D) steady-state flows of an incompressible viscoelastic fluid through a porous medium. Applying the elliptic regularization method and arguments from the topological degree theory, we prove a theorem about the weak solvability of the corresponding boundary value problem under an inhomogeneous Dirichlet boundary condition. Using this theorem, we obtain sufficient conditions for the existence of optimal weak solutions minimizing a given cost function. Moreover, it is shown that the set of all optimal weak solutions is bounded and sequentially weakly closed in an appropriate function space. Full article

We investigate cosmological scenarios in a spatially flat Friedmann–Lemaître–Robertson–Walker (FLRW) universe containing Ricci-type holographic dark energy within the framework of general relativity. The cosmic fluid is composed of baryonic matter, radiation, cold dark matter, and dark energy. We consider three phenomenological interaction schemes in the dark sector and derive analytic expressions for the standard cosmological quantities in each case. Using observational data from cosmic chronometers and Type Ia supernovae (Pantheon sample), we constrain the parameters of the interacting models and determine their best-fit values. Finally, we compare the interacting holographic scenarios with the concordance ɅCDM (Ʌ cold dark matter) model at the background level, displaying contour plots for the cosmological and interaction parameters and discussing the performance of the models in light of earlier results in the literature. Full article

Molten salts are essential heat transfer and storage media in high-temperature applications such as Concentrated Solar Power (CSP), owing to their high boiling points, low vapor pressures, and excellent thermal stability. The overall performance of such systems is largely governed by the convective heat transfer characteristics of molten salt fluids. This review systematically synthesizes recent advances over the past five years in enhancing the thermophysical properties and convective heat transfer of molten salts, focusing on two primary strategies: improving the intrinsic properties of molten salts through nanoparticle doping, and optimizing the structural design of heat exchangers. The enhancement of thermophysical properties is mainly achieved by preparing molten salt-based nanofluids. Dispersing low concentrations (typically 0.1–1.0 wt.%) of nanoparticles such as SiO₂, Al₂O₃, and carbon nanotubes (CNTs) can yield significant improvements—thermal conductivity increases of up to ~100% (e.g., 0.5 wt% SiO₂ in NaNO₃-KNO₃) and specific heat capacity enhancements of 20–30% (e.g., 1.0 wt% Al₂O₃ in carbonates). Multiscale simulations, particularly molecular dynamics (MD), have revealed key enhancement mechanisms, including the formation of ordered ionic layers on nanoparticle surfaces that create efficient nanoscale heat conduction pathways, and the modulation of ion–ion interactions. Concurrently, significant heat transfer enhancement can be achieved through structural optimization. Single-method technologies, such as enhanced heat transfer tubes, improve performance by disrupting the thermal boundary layer. For instance, spirally grooved tubes can increase the Nusselt number (Nu) by 19% for Re > 25,000, while twisted tape inserts can enhance laminar flow heat transfer by up to 8.6 times. Composite strategies that couple nanofluids with enhanced geometries demonstrate superior overall performance, with Performance Evaluation Criterion (PEC) values reaching up to 1.48 for converging–diverging tubes with SiO₂ nanofluids and 1.21 for trefoil-shaped U-tubes with Cu-based nanofluids. Compact heat exchangers (CHEs) offer high efficiency, achieving PEC values of 1.07–1.4 in optimized designs, but face challenges such as clogging risks in large-scale applications. Future research directions include the development of advanced composite molten salts, the application of artificial intelligence and multiscale simulations for mechanistic analysis and design optimization, the fabrication of novel heat exchanger structures via additive manufacturing, and cross-disciplinary integration for full-chain system optimization. These concerted efforts are essential for realizing efficient, cost-effective, and reliable molten salt-based energy systems. Full article

Background/Objectives: Acute ischemic stroke (AIS) is one of the leading causes of mortality worldwide and the primary cause of acquired neurological disability in adults. As part of a stroke magnetic resonance (MR) protocol, fluid-attenuated inversion recovery (FLAIR) plays an important role in the detection and assessment of the degree of leukoaraiosis (LA), while susceptibility-weighted angiography (SWAN) detects cerebral microbleeds (CMBs). The present study sought to examine the association of the degree of LA and CMBs with absolute cerebral blood flow (aCBF) values and functional outcome prediction in patients with AIS. Methods: We conducted a cross-sectional study including a total of 205 male and female patients. All of the patients underwent brain magnetic resonance imaging (MRI) examinations in the first 24 h following suspected AIS, using the stroke protocol. A modified Rankin scale (mRS) was used to evaluate the degree of functional dependence and disability three months after AIS. Results: The incidence of an unfavorable functional outcome evidently increased with more pronounced LA modalities (p < 0.05; χ² test). The Kruskal–Wallis test found a statistically significant difference in aCBF values in relation to a degree of LA (p < 0.05). As there were a small number of multiple CMBs, no statistically significant difference was found based on the detection and degree of CMBs with aCBF and functional outcome; hence, the hypothesis was not entirely confirmed. Conclusions: This study indicates the reliability of MRI application in the initial diagnostic evaluation in order to gain an additional insight into the prediction of AIS outcomes. We demonstrated that LA correlates significantly with an unfavorable functional outcome after AIS, with decreased perfusion values. On the other hand, a higher proportion of unfavorable functional outcomes was observed in patients with CMBs. However, this result was not statistically significant and should be interpreted with caution. Full article

As a critical component of the hydrogen supply system for fuel cells in hydrogen-powered unmanned aerial vehicles (UAVs), the dynamic performance of the two-stage hydrogen pressure-reducing valve (PRV) directly influences the stability and safety of the fuel cell system. To address the insufficient output pressure control accuracy of existing hydrogen PRVs under a 70 MPa inlet pressure, this study designs a compact, fast-response, and high-precision two-stage hydrogen PRV. The flow coefficients of the valve orifices at each stage are obtained through Computational Fluid Dynamics (CFD) simulations, based on which a multi-physics coupled system dynamics model of the two-stage hydrogen PRV is derived. Using this multi-physics coupled dynamics model, a dynamic characteristic simulation model is established in MATLAB/Simulink. Numerical simulations performed with this model reveal the influence of different structural parameters on the dynamic characteristics of the first-stage and second-stage PRVs. The results provide theoretical and methodological references for the structural design and efficient optimization of two-stage hydrogen PRVs under high-pressure differential conditions, offering important guidance for improving the safety and stability of fuel cell hydrogen supply systems. Full article

Air-cooled heat sinks remain a practical and cost-effective solution for thermal management in high power-density electronic systems. This study investigates the thermal–hydraulic performance of a plate pin-fin heat sink operating under forced convection, with emphasis on the coupled interaction between heat-transfer enhancement and pressure-drop penalty. The proposed hybrid configuration combines the low flow resistance of plate fins with the wake-induced mixing characteristics of pin-fin elements, thereby modifying boundary-layer development and flow structures within the fin channels. This review comprehensively analyzes existing experimental measurements across a range of Reynolds numbers to evaluate the average Nusselt number, thermal resistance, and friction factor. The results demonstrate that the inclusion of pin elements significantly enhances convective heat transfer through increased flow disruption and vortex formation, while incurring a moderate increase in pressure loss relative to conventional plate-fin designs. In addition, flow visualization and temperature mapping reveal improved heat transfer uniformity along the streamwise direction, particularly at intermediate Reynolds numbers where transition effects become pronounced. Empirical correlations were developed to relate the Nusselt number and friction factor to Reynolds number and key geometric ratios, providing predictive capability for thermo-hydraulic performance assessment. The findings indicate that fin-scale geometric optimization plays a dominant role in achieving improved overall performance and that the plate pin-fin configuration offers a favorable trade-off between heat-transfer augmentation and hydraulic efficiency for forced-convection electronic cooling applications. Full article

Hyphae fungi of the Trichoderma genus are widely recognized as effective biological control factors (BCAs) due to their ability to inhibit the growth of plant pathogens through a variety of mechanisms such as mycoparasitism, antibiotics or competition for resources. Specialized secondary metabolites (SMs), including volatile organic compounds (VOCs), lytic enzymes and surfactants, play an important role in these interactions. The aim of this study was to evaluate the antagonistic activity and characterization of secondary metabolites from the aqueous phase or suspended in an organic solvent produced by three strains of Trichoderma citrinoviride. The study focused on their enzymatic properties, surfactant potential and effect on the growth kinetics of sixteen fungal species. Antagonistic activity against phytopathogens was tested using the turbidimetric method, analyzing various forms of preparations. Lytic enzyme activity and surface tension of fluids were also evaluated. The C1 strain showed the broadest spectrum of antagonistic activity. Analysis of growth kinetics revealed that the way metabolites are prepared is crucial for their efficacy. Studies have shown that the effectiveness of biocontrol depends not only on the Trichoderma strain, but also on the extraction method and form of the preparation (e.g., rehydration of lyophilizate vs. organic phase extraction). The presence of diverse metabolites, including lytic enzymes, biosurfactants and volatile organic compounds, indicates a complex mechanism of action of T. citrinoviride, making this species an ideal candidate for the production of plant protection biopreparations. Full article

To achieve high-speed quantitative hole sowing of rice using an unmanned aerial vehicle (UAV), this study proposes an agricultural UAV pneumatic hole sowing system suitable for high-speed quantitative hole sowing. This system is based on pelletizing rice seeds. A pneumatic seed distribution system based on the Venturi effect was designed, with a seed feeding device that employs a computational fluid dynamics–discrete element method (CFD-DEM) coupled simulation method to construct a gas–solid two-phase flow simulation model that simulates actual field sowing conditions and analyzes seed transport characteristics. Using the seed feeding device blending chamber height, expansion section cone angle, and inlet airflow velocity as experimental factors, and evaluating seed distribution statistics based on the hole formation ratio(HFR) and hole spacing coefficient of variation (HSCV), the study achieved a comprehensive statistical analysis of seed distribution patterns. The Box–Behnken orthogonal experiment optimized the structural parameters of the seed feeding device, determining the optimal airflow velocity during seeding. The optimized parameter combination yielded a blending chamber height of 15.59 mm, an expansion section cone angle of 22.20°, and an inlet airflow velocity of 19.67 m/s, corresponding to an HFR of 84.66% and an HSCV of 6.95%. Field trials validated an HFR of 86.25% and an HSCV of 6.83%. This study provides theoretical and technical support for the design of high-speed hole -sowing equipment for rice using a UAV. Full article

The Permian Qixia dolostone in the Central Sichuan Basin is a significant hydrocarbon reservoir of hydrothermal origin, linked to the Emeishan Large Igneous Province and structurally controlled by E–W strike–slip faults. However, how this process controls reservoir quality remains poorly understood. To address this, we integrate core observation, thin-section petrography, XRD analysis, thickness mapping, MICP, and μ-CT to characterize the lithofacies and pore structures of the Qixia Formation in the study area. Six lithofacies are recognized, including mudstone (F1), wackestone (F2), packstone (F3), grainstone (F4), rudstone (F5), and dolostone (F6), and F6 is further divided into three subtypes (F6-1, F6-2, F6-3). Dolostones exhibit superior reservoir quality relative to limestones, and among the dolostone, reservoir quality improves progressively from F6-1 to F6-3 with increasing crystal size and dolomite content. Dolostone distribution is spatially tied to E–W strike–slip faults, and its formation age coincides with documented fault activity, implicating these faults as the primary fluid conduits. Quantitative pore structure analyses further indicates that dolomitization enhanced permeability by enlarging pore–throat radii and improving macropore connectivity, with associated dissolution contributing additional secondary porosity. Full article

The physicochemical controls on gold precipitation in orogenic gold deposits remain poorly constrained, with traditional fluid inclusion and isotopic studies often yielding ambiguous results due to overprinting or incomplete records. This study addresses this challenge using chlorite—a sensitive mineral proxy for fluid conditions—as a quantitative sensor in the Jinshan orogenic gold deposit (>200 t Au) of the Jiangnan orogenic belt, South China. Hosted in Neoproterozoic phyllite within NE–NNE-trending ductile–brittle shear zones, Jinshan features auriferous quartz–polymetallic sulfide veins with prominent chlorite alteration. Integrating high-resolution SEM-EPMA analyses of multi-generational chlorite with thermodynamic modeling, we reconstruct the temporal evolution of temperature, oxygen fugacity (fO₂), pH and sulfur fugacity (fS₂) during ore formation. Four paragenetic stages are identified: Stage 1 (ankerite–quartz), Stage 2 (pyrite–arsenopyrite–quartz), Stage 3 (quartz–gold–polymetallic sulfide), and Stage 4 (chlorite–carbonate–quartz). Electron microprobe analysis reveals that the chlorite composition changes from Fe-rich chamosite (Stage 2) to Mg-rich clinochlore (Stage 3) and then to Fe-rich chamosite (Stage 4). Chlorite from Stage 2 (Chl-1) formed metasomatically at low fluid/rock ratios, while Stage 3 and 4 chlorites (Chl-2 and Chl-3) precipitated directly from higher fluid/rock ratio fluids. Chlorite compositions record a critical Stage 2–3 transition involving cooling from ~ 320 °C to ~ 260 °C, reduction (log fO₂ from –33.6 to –39.7), and alkalinization, and sulfur fugacity remained stable within a narrow range (log fS₂ = –13.6 to –8.0), followed in Stage 4 by minor reheating to ~280 °C, re-acidification, and a slight rebound in oxygen fugacity. Thermodynamic simulations reveal that the destabilization of Au(HS)₂^- complexes, primarily driven by the synergistic effects of cooling, pH increase, and decreasing oxygen fugacity, triggered gold precipitation during the main ore stage. Results demonstrate that abrupt cooling coupled with fluid alkalinization and reduction exerted the dominant control on gold precipitation in Jinshan, resolving long-standing debates on ore-forming mechanisms and highlighting chlorite as a robust quantitative sensor for fluid evolution. Full article

This study investigates the temperature distribution characteristics, temperature rise behavior, and the thermal effects on the output torque in a Permanent Magnet/Magnetorheological Fluid (PM/MRF) variable-stiffness drive joint through a combined approach of simulation and experimentation. First, a thermal simulation model of the joint was established using COMSOL Multiphysics, and steady-state and transient temperature field analyses were conducted under slip powers ranging from 25 W to 100 W. The steady-state results show that, when the joint reaches thermal equilibrium under 100 W, its internal maximum temperature is 113 °C, which falls within the allowable operating temperature range of the MRF. Transient simulations indicate that, within 180 s, the temperature in the working area of the joint continuously rises, but the rate of temperature increase gradually slows down, with a maximum temperature rise of 18.35 °C observed in the transmission mode. Furthermore, an experimental test system was constructed to conduct temperature rise characteristic tests and torque temperature characteristic tests on the joint. The experimental results show that the maximum actual temperature rise measured within 180 s in transmission mode was 17.36 °C, slightly lower than the simulated prediction. Within the temperature variation range of 10 °C to 50 °C, the maximum reductions in driving torque and braking torque were 14.1% and 14.9%, respectively. The study demonstrates that, under short-term operating conditions, the effect of the internal temperature rise on the output torque is predictable and can be mitigated through closed-loop current compensation. These findings provide theoretical and experimental foundations for the thermal safety design and high-precision control of PM/MRF variable-stiffness joints. Full article

In recent years, oil and gas exploration in the Lower Cambrian of the central–northern Sichuan Basin, China, has demonstrated enormous resource potential. As a potential interval of high-quality hydrocarbon source rocks, the Canglangpu Formation of the Lower Cambrian remains underdeveloped in exploration and lacks in-depth research. Affected by tectonics, sedimentary environment, and diagenesis, the genetic mechanisms and genetic models of carbonate reservoirs in the Canglangpu Formation within the study area need further clarification. This study utilizes petrological characteristics of dolomite and geochemical data to clarify diagenetic fluids of different reservoir rocks and identifies the main controlling factors and development models of the reservoirs. The results show that the dolomites in Member 1 of the Canglangpu Formation (Cang-1 Member) in central–northern Sichuan are mainly classified into three types: silty–fine crystalline dolomite (D1), granular dolomite (D2), and residual-texture dolomite (D3). The reservoir spaces are dominated by intercrystalline pores, intergranular pores, and structural fractures. The porosity of the Cang-1 Member in the area is relatively low, with an average porosity of 5% or lower. The reservoir porosity average is 3.63%, belonging to low-porosity reservoirs. The permeability average is 2.94 × 10⁻³ mD. Analysis of different geochemical indicators indicates that the diagenetic fluids of the three dolomite types are mainly syndepositional seawater. D1 is formed by penecontemporaneous dolomitization, while both D2 and D3 are formed during the shallow-to-middle burial stage. The main controlling factors of dolomite reservoirs include sedimentary facies, diagenesis, and tectonic movement. This study clarifies the genesis and development model of dolomite reservoirs in the Cang-1 Member, aiming to provide reliable and valuable references for the exploration of dolomite reservoirs in the Canglangpu Formation of the Sichuan Basin. Full article

Background and Objectives: Severe burn injuries are still associated with high mortality. The length of intensive care stay is strongly influenced by the severity of organ failure, with multi-organ failure being the main cause of death in up to 40% of cases. Liver dysfunction is the second most common organ failure. Conventional diagnosis relies on static laboratory parameters that reflect damage already caused. Measuring the hepatic clearance of indocyanine green (LiMON^®) offers a dynamic, bedside method for detecting liver dysfunction early, enabling timely therapy adjustments. Materials and Methods: In this prospective single-centre observational study, all patients admitted to the Unfallkrankenhaus Berlin Burns Centre from October 2022 to September 2024 with ≥30% TBSA burns were included. Liver function was assessed via LiMON^® within 24 h post-injury and every 48 h until day 14 or ICU discharge. Static liver parameters were measured in parallel. Results: We included a total of 23 patients. An initial measurement was only successful in 18 cases. On admission, six patients (33%) had normal liver function with a plasma duration rate (PDR) > 18% (PDR 30.9 ± 7.3%), while 12 (67%) showed reduced clearance (PDR 14.5 ± 2.6%). In 75% of cases (n = 9), function recovered within 48 h. Based on PDR progression, four liver function patterns were defined: “stable”, “recovery”, “late insufficiency”, and “failure”; a fifth pattern included all patients who were deceased during this study (“death”). These groups differed in fluid therapy, plasma transfusion, and catecholamines administered. PDR correlated well with aminotransferase levels. Conclusions: Dynamic liver function monitoring enables earlier detection of impairment than static markers. Early identification of at-risk patients could guide fluid management and improve outcomes. LiMON^® is a valuable tool in burn care, though alternative methods may be needed in patients with severe systemic hypoperfusion. Full article

The North China Craton (NCC) hosts numerous world-class Au deposits and these Au deposits can be classified into the Au-only and Ag-Au polymetallics, respectively. The former is mostly located in the eastern NCC, such as in the giant Jiaodong Province, and the latter is mostly distributed along the northern and southern margins of the NCC. Compared with Au-only deposits, the ore genesis of the Ag-Au deposits remains controversial. This paper focuses on the Niujuan Ag-Au deposit in the Fengning ore cluster of the northern margin of the NCC. Detailed deposit geology investigation, texture analysis, and analyses of the in situ trace element and sulfur isotope compositions of pyrite, coupled with H-O isotope compositions of quartz from different stages, were conducted to elucidate the ore-forming processes and metal sources. The results showed that the formation of the Niujuan deposit can be divided into four stages, including a pre-ore siliceous breccia stage (stage 1), syn-ore quartz-pyrite stage (stage 2), syn-ore polymetallic sulfide stage (stage 3), and post-ore fluorite-calcite stage (stage 4). Among these, stage 3 represents the major Ag-Au mineralization stage. Pyrite is well developed within stage 2 and stage 3, representing the intensive sulfidation of the wall rock. Microscopic analytical techniques including gamma-enhanced reflected light and scanning electron microscopy backscattered electron (BSE) reveal that pyrite samples from stage 2 and stage 3 have distinct textures. Pyrite (Py1) from stage 2 is homogeneous but with numerous pores. In contrast, pyrite (Py2) from stage 3 has overgrowth textures, and be divided into three sub-stages from core to rim (Py2a, Py2b, and Py2c) with different BSE brightness levels. LA-ICP-MS trace elements analyses results show that these different stages of pyrite show different composition such as Au, As, Ag, Co, and Ni. Py1 has low Au and Ag concentrations ranging from < 0.1 ppm to 0.02 ppm and < 0.1 ppm to 21.8 ppm, respectively. Py2a has low Au and Ag concentrations ranging from < 0.1 ppm to 0.4 ppm and 0.4 ppm to 118.4 ppm, respectively. Py2b is characterized by high As and low Au contents, with average values of 6670.8 ppm for As and 1.4 ppm for Au. Py2c shows relatively low Co and Ni concentrations ranging from 0.02 ppm to 255.2 ppm and < 0.1 ppm to 9.9 ppm, respectively. The sulfur isotope composition of Py1 and Py2 is relatively consistent, ranging from 3.8‰ to 6.7‰. The H and O isotope compositions of quartz from stage 1, stage 2, and stage 3 have insignificant variations, ranging from −119.5‰ to −101.3‰ for δD and −6.8‰ to −3.7‰ for δ¹⁸O_fluid, respectively. The results show that sulfur and, possibly, Au and Ag were mainly derived from magmatic hydrothermal fluids, and a significant amount of meteoric water was involved. Combined with the published mineralizing ages (~140 Ma), this paper suggests that the Niujuan Ag-Au deposit formed during the Early Cretaceous under an extensional setting in response to the eastward retreating subduction of the Paleo-Pacific oceanic plate. Evidence from deposit geology and geochemistry reveals that the mixture of magmatic and meteoric water, together with intensive sulfidation, is the key factor controlling Au and Ag deposition. Full article