Search Results (13,798)

The exhaust purge on the anode side is a critical step in the operation of fuel cell systems, and optimizing the exhaust interval time is essential for enhancing stack efficiency and hydrogen utilization. This paper proposed a method to determine the purge strategy of hydrogen supply system based on theoretical and simulation analysis. To investigate the impact of anode purge strategy on the performance of automotive fuel cells, a model of a 100 kW fuel cell stack and a dual-ejector hydrogen supply system was developed in MATLAB/Simulink(R2022b) using principles of fluid dynamics, simulation, and experimental data. This model effectively captures the accumulation and exhaust of hydrogen, nitrogen, and vapor within the anode. Simulations were conducted under seven different exhaust interval times at varying current densities to study the effect of exhaust interval on the performance of the fuel cell. The results indicate that for a 100 kW fuel cell, the exhaust interval time should be controlled within 25 s and should decrease as the current density increases. At low current density, increasing the exhaust interval has a more significant effect on improving hydrogen utilization. At high current density, reducing the exhaust interval helps maintain a stable hydrogen excess ratio and shortens the time required for the output voltage to reach a stable state. Full article

Background and Objectives: Vertebral metastases often lead to pathological fractures and spinal cord compression, thus impacting patient quality of life. This study aimed to quantify the poroelastic mechanical properties of vertebral metastatic tissue explanted during spine surgery and correlate it with clinical data. Methods: Nine patients (61.7 ± 13.1 years) were prospectively recruited from April 2021 to February 2022, where 78% had a vertebral fracture. Demographic and metastases data, including primary origin, spinal level, lesion volume, and SINS score, were collected, and tissue specimens were explanted during surgery. Using a newly developed portable experimental setup, confined compression creep tests were conducted to measure the aggregate modulus and permeability of each sample. Dealing with limited samples, the results were expressed as the median (min; max). Results: Specimens from the unfractured vertebrae had higher aggregate modulus (200.35 (149.80; 250.90) kPa vs. 14.47 (8.27; 35.89) kPa) and higher permeability (0.02 (0.01; 0.03) mm⁴/N·s vs. 0.41 (0.10; 4.68) mm⁴/N·s) compared with the specimens from the fractured vertebrae. Histology revealed prominent levels of neoplastic cell infiltration and disruption of typical bone matrix architecture. Specimens with low neoplastic cellularity had comparable or slightly higher poroelastic properties compared to high cellularity. No clear trend was observed between the mechanical properties and SINS score, nor between the mechanical properties, percentage lesion volume, and fractures. Conclusions: Despite the limited sample size, the poroelastic characterization revealed relevant insights to investigate in future research. A transdisciplinary assessment of vertebral metastases, incorporating poroelastic testing, deserves further attention and could enhance the treatment options. Full article

This study investigates the potential of utilising the proteolytic activity of two different strains, Levilactobacillus brevis FST140 and Pediococcus pentosaceus FST22, to assess their impact on wheat gluten proteins. A high-power ultrasound (US) treatment (850 kHz; 500 W/cm²; 35 °C) was used to activate the proteolytic system of LAB to promote gliadin-like protein degradation in wheat wholemeal-based sourdough. The proteolytic activity of L. brevis and P. pentosaceus increased two-fold with 10 and 20 min US stimulation, respectively, compared to fermentation without ultrasonication. Regarding the impact of proteolysis and sonication on gliadin proteins, fermentation with both strains reduced gliadin content in commercial gluten by an average of 77.4% compared to the untreated sample, and additional US treatment further enhanced gliadin degradation efficiency to an average of 83.5%. The combined application of US and lactic acid fermentation initiated a seven-fold decrease in wheat wholemeal flour (WF) gliadin levels compared to the untreated sample (47.2 mg/g). Furthermore, the synergistic application of US, LAB, and yeast fermentation allowed us to reduce gliadin content up to 1.6 mg/g, as well as to reduce gluten content in the sourdough up to 3 mg/g. Despite complete hydrolysis of the gliadin fraction under the combined effects of US and fermentation, glutenins were less affected by the applied treatments in all cases. The technology presented in this study offers a promising approach for producing gluten-free or low-gluten fermented products in the bread-making industry. Full article

In the continuous casting of special steel blooms, low casting speeds result in slow renewal of the molten steel surface in the mold, adversely affecting mold flux melting and liquid slag layer supply, which may lead to surface cracks, slag entrapment, and breakout incidents. To optimize the flow and heat transfer behavior in the mold, a three-dimensional numerical model was developed based on the VOF multiphase flow model, $k-ϵ$ RNG turbulence model, and DPM discrete phase model, employing the finite volume method with SIMPLEC algorithm for solution. The effects of casting speed, argon injection rate, and mold flux properties were systematically investigated. Simulation results demonstrate that when casting speed increases from 0.35 m·min⁻¹ to 0.75 m·min⁻¹, the jet penetration depth increases by 200 mm and meniscus velocity rises by 0.014 m·s⁻¹. Increasing argon flow rate from 0.50 L·min⁻¹ to 1.00 L·min⁻¹ leads to 350 mm deeper bubble penetration, 10 mm reduction in jet penetration depth, 0.002 m·s⁻¹ increase in meniscus velocity, and decreased meniscus temperature due to bubble cooling. When mold flux viscosity increases from 0.2 Pa·s to 0.6 Pa·s, the average liquid slag velocity decreases by 0.006 m·s⁻¹ with a maximum temperature drop of 10 K. Increasing density from 2484 kg·m⁻³ to 2884 kg·m⁻³ results in 0.005 m·s⁻¹ higher slag velocity and average 8 K temperature reduction. Comprehensive analysis indicates that optimal operational parameters are casting speed 0.35–0.45 m·min⁻¹, argon flow ≤ 0.50 L·min⁻¹, mold flux viscosity 0.2–0.4 Pa·s, and density 2484–2684 kg·m⁻³. These conditions ensure more stable flow and heat transfer characteristics, effectively reducing slab defects and improving casting process stability. Full article

Fiber optic sensors are increasingly used to measure dynamic strain fields caused by the propagation of mechanical waves. Their low intrusiveness when embedded within a structure makes them suitable for a wide range of applications. In this paper, the feasibility of integrating fiber Bragg gratings (FBGs) into castable materials for ultrasonic applications is investigated. We employed castable polyurethane resins, which are widely used in industry due to their reproducible and durable mechanical properties. Our study began with an analysis of fiber integration by examining the 1D strain profiles of two polyurethane resins during their polymerization and also the impact of their hardening on the central wavelength value of several FBGs spectra. Subsequently, we assessed the sensitivity of FBGs to ultrasonic waves generated at 100 kHz after resin polymerization. Specifically, we explored how the fiber coating influences the rate of energy transfer from the host material to the fiber core. Our findings demonstrate that the central wavelength shift in the FBG reflectivity spectra, caused by shrinkage during resin polymerization, can reach up to 10 nm. This shift must be considered when selecting FBG wavelengths to prevent the reflectivity spectra from falling outside the permissible range of the interrogation system. We measured exploitable ultrasonic waves propagating in the resin samples. Preliminary observations suggest the presence of early arrivals, which could potentially correspond to crosstalk effects between the FBGs even though they are centered at different wavelengths. Furthermore, we show that in dynamic strain fields caused by ultrasonic wave propagation, both acrylate and polyimide coatings transmit similar amounts of energy to the fiber core. These preliminary results highlight the potential of using FBGs as ultrasonic wave sensors embedded in castable materials such as polyurethane resins. Full article

Natural products have extensive attractiveness as therapeutic agents due to their low toxicity and high efficiency. Our previous study has identified a depside-type Aspergillusidone G (Asp G) derived from Aspergillus unguis DLEP2008001, which shows excellent neuroprotective activity for 1-methyl-4-phenylpyridinium (MPP⁺)-induced primary cortical neurons and anti-neuroinflammatory property, promising to be a potential therapeutic agent for Parkinson’s disease (PD). To further explore the anti-PD potential and mechanisms of Asp G, we employed network pharmacology, cellular experiments, and various biological techniques for analysis and validation. The analysis of network pharmacology suggested that Asp G’s anti-PD potential might be attributed to its modulation of inflammation. The data from nitric oxide (NO) detection, qRT-PCR, and Western blot confirmed that Asp G dose-dependently inhibited lipopolysaccharide (LPS)-stimulated NO production, with 40 μM Asp G suppressing 90.54% of the NO burst compared to the LPS group, and suppressed the overproduction of inflammatory-related factors in LPS-induced BV2 cells. Further protein–protein interaction analysis indicated that matrix metalloproteinase 9 (MMP9), a promising target for PD intervention, was the most likely anti-PD target of Asp G, and the results of gelatin zymography, qRT-PCR, and Western blot validated that Asp G could inhibit the active and inactive forms of MMP9 directly and indirectly, respectively. Notably, the inhibition of 67 kDa-MMP9 by Asp G is expected to compensate for the inability of TIMP-1 to inhibit this form. Furthermore, a selective inhibitor of MMP9 (20 μM SB-3CT) further potentiated the anti-inflammatory effects of Asp G (20 μM), with inhibition rate on NO increasing from 27.57% to 63.50% compared to LPS group. In summary, our study revealed that Asp G exerts anti-neuroinflammatory effects by inhibiting MMP9, which provides a valuable lead compound for the development of anti-neuroinflammatory drugs and offers insights into the intervention of PD-associated neuroinflammation. Future studies will further investigate the upstream regulatory mechanisms of Asp G-mediated MMP9 inhibition and its effects in in vivo PD models. Full article

Perennial ryegrass represents the most important forage grass, yet its generally low drought tolerance leads to reduced yields under water scarcity. Nevertheless, large intra- and inter-population variability could be a pool for selecting new drought-tolerant varieties. In this study we evaluated three populations (K-11, Exp population and Shandon) under semi-controlled conditions across four watering levels (100%, 70%, 50% and 30% of field water capacity), focusing on yield and key morphological and biochemical traits. Dry matter yield and root dry mass decreased in all populations under limited watering conditions. The highest biomass production in such conditions was observed in the Exp population, likely due to better root performance in the deeper soil layer. On the other hand, oxidative stress markers (MDA and H₂O₂) and water-soluble sugars, which indicated the best physiological status in cultivar K-11 under severe drought, did not lead to the highest DMY. These results show the importance of including multiple physiological and biochemical traits in breeding processes, with the aim of developing perennial ryegrass cultivars capable of withstanding prolonged and intense summer drought as a consequence of climate change. Full article

This paper investigates the frost heave and thaw settlement characteristics of the pipe–soil system during the freeze–thaw cycle, along with the underlying mechanisms. A numerical simulation platform for the complex pipe–soil system was developed using the heat conduction equation, moisture migration equation, and stress–strain equation, all of which account for the ice–water phase change process. The simulations were performed with the coefficient-type partial differential equation (PDE) module in COMSOL Multiphysics. By employing coupled thermal–hydraulic–mechanical (THM) simulation methods, the study analyzed the changes in volumetric water content, volumetric ice content, moisture migration patterns, and temperature field distribution of a water pipeline after three years of service under real engineering conditions in the cold region of northern Xinjiang, China. The study also examined the effects of parameters such as pipeline burial depth, specific heat capacity, thermal conductivity, permeability of saturated soil, and initial saturation on the displacement field. The results show that selecting soil layers with high specific heat capacity (e.g., 1.68 kJ/kg·°C) and materials with high thermal conductivity (e.g., 2.25 W/m·°C) can reduce surface frost heave displacement by up to 40.8% compared to low-conductivity conditions. The maximum freezing depth near the pipeline is limited to 0.87 m due to the thermal buffering effect of water flow. This research provides a scientific reference and theoretical foundation for the design of frost heave resistance in water pipelines in seasonally frozen regions. Full article

Laser alloying was used to form metal matrix composite layers strengthened by WC particles. The process parameters were selected in such a way that there was no complete melting of the WC particles. Four different laser beam powers (from 0.65 kW to 1.3 kW) were used, generating different temperature distributions during processing. The temperature across the laser track axis was determined according to the mathematical model proposed by Ashby and Esterling. All layers produced contained unmelted WC particles in an aluminum-based matrix. The depth of the WC-Al composite layers strongly depended on the applied laser beam power. The lowest thickness of 198 ± 36 µm was measured for the layer produced at a laser beam power of 0.65 kW. A twofold increase in power P was the reason for obtaining a thickness th_AZ = 387 ± 21 µm. The power of the laser beam also affected the percentage of the substrate material (7075 alloy) in the molten pool during the laser processing. As a result, the highest amount of substrate material was obtained for the WC-Al composite layer produced using the highest laser beam power P = 1.3 kW. Simultaneously, this layer was characterized by the lowest percentage of tungsten carbide particles in this layer. The temperature profile along the axis of the laser track and also the maximum temperature reached confirmed the difference in the bonding between the reinforcing WC particles and the metal matrix. For P = 0.65 kW, too low a temperature was reached for the tungsten carbide particles to overmelt, resulting in poor bonding to the metallic matrix in the layer. Moreover, the layer showed serious defects such as discontinuity, porosity, and cracks. As a result, the WC-Al composite layer produced at the lowest laser beam power was characterized by a wear resistance lower (I_mw = 6.094 mg/cm²/h) than the 7075 alloy without surface layer (I_mw = 5.288 mg/cm²). The highest wear resistance was characteristic of the 7075 alloy laser alloyed with a laser beam power equal to 1.17 kW (I_mw = 2.475 mg/cm²/h). This layer showed satisfactory quality and adhesion to the substrate material. Full article

Low-flow events significantly impact water users and ecosystems due to reduced flow rates and deteriorating water quality. Elevated water temperatures during these periods have led to economic and ecological consequences. Therefore, water temperature is a key aspect in the context of low-flow risk analysis, and it is essential to model it accurately. This study introduces a one-dimensional water temperature model optimized for integration into low-flow risk analysis frameworks. Results demonstrate good performance in simulating water temperatures for both rivers, with Nash–Sutcliffe efficiency values of 0.85–0.98 and root mean square errors of 0.96–1.96 K. The model was evaluated on two contrasting river systems: the small Selke River and the large Elbe River. The model effectively captures anthropogenic influences and altered environmental conditions. Key factors influencing water temperature varied by river size, with tributaries and shading having more impact on smaller rivers, while air temperature was the primary driver for larger rivers. The model’s computational efficiency enables the practical implementation of long-term risk assessments. This temperature model fulfills the requirements for integration into low-flow risk management frameworks, providing a valuable tool for assessing temperature-related impacts and evaluating mitigation strategies across diverse river systems. Full article

Bupleurum scorzonerifolium Willd. is a commonly used bulk Chinese herbal remedy. Due to the large-scale mining of wild Bupleurum scorzonerifolium Willd., its natural resources are gradually exhausted. In addition, there are some problems in Bupleurum scorzonerifolium Willd. cultivation, such as lack of guidance, excessive application of fertilizers and so on, which lead to the yield and quality of Bupleurum to be below the standard value. Therefore, it is significant to clarify the regulation of quality and yield under different levels of fertilizers. In this study, three different levels of potassium fertilizer were applied; then, the metabolites in different parts of Bupleurum were analyzed by gas chromatography–mass spectrometry (GC–MS) to detect the alterations in the metabolic spectrum and recognize both the accumulation and distribution of key metabolites in response to each level of potassium fertilizer. The contents of various mineral elements, such as sodium, calcium, potassium, magnesium, manganese, zinc, iron, and copper, in different parts of Bupleurum under different potassium levels were determined. Potassium fertilizer had a significant impact on the absorption and distribution of these mineral elements. There were synergistic and antagonistic effects between each element and K⁺. The results showed that low and high potassium levels could promote the progression of main shoots and roots, but inhibited the accumulation of dry matter in lateral shoots and flowers. Low potassium levels stimulated the content of saikosaponin a in all plant parts, while high potassium levels inhibited the accumulation of most saikosaponin a,c and d. A total of 77 metabolites were identified by GC–MS, of which glycerol, d-glucose, silane and copper phthalocyanine were highlighted as the key metabolites in response to potassium fertilizer. The abovementioned metabolites are mapped into insulin signaling pathways, streptomycin biosynthesis, galactose metabolism and other metabolic pathways, sustaining the metabolic regulation of Bupleurum scorzonerifolium Willd. Full article

The global rise in antimicrobial resistance, particularly among ESKAPE pathogens, has intensified the demand for alternative therapeutic strategies. Silver nanoparticles (AgNPs) have exhibited broad-spectrum antimicrobial activity and represent a promising approach to combat multidrug-resistant infections. This study aimed to synthesize and functionalize AgNPs using various polymeric agents—ethylene glycol (EG), polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and their combinations—and to evaluate their antimicrobial and antibiofilm efficacy against clinically relevant bacterial strains. AgNPs were synthesized via chemical reduction and functionalized as Ag@EG, Ag@PEG, Ag@EG/PVP, and Ag@PEG/PVP. A total of 68 clinical isolates—including Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus lugdunensis, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa—were tested. Antimicrobial susceptibility was assessed using disc diffusion and broth microdilution assays, while antibiofilm activity was evaluated via the crystal violet method. Among all tested formulations, Ag@EG/PVP exhibited the highest antimicrobial and antibiofilm activity, with notably low minimum inhibitory concentrations (MIC₅₀) and minimum biofilm eradication concentrations (MBEC₅₀) for Ps. aeruginosa and K. pneumoniae. In contrast, AgNPs functionalized with PEG or EG alone showed limited efficacy. Biofilm-forming isolates, particularly Staphylococcus spp., required higher concentrations for inhibition. These results highlight the critical role of functionalization in modulating the antimicrobial properties of AgNPs, with Ag@EG/PVP demonstrating potent activity against both planktonic and biofilm-associated multidrug-resistant bacteria. Overall, this study supports further developing AgNPs-based formulations as adjuncts or alternatives to conventional antibiotics, particularly for managing biofilm-related infections. Future research should focus on formulation optimization, safety assessment, and translational potential. Full article

The construction sector plays a key role in climate change due to its high energy consumption and greenhouse gas emissions. Developing environmentally friendly building materials with low environmental impact is essential to improving energy efficiency. Insulation derived from agricultural waste is particularly promising due to its low ecological footprint, responsible resources use, and potential for integration into various construction systems. This study evaluates the potential of rice husk fiber as a thermal insulating material applied through the blowing technique in the Skylark 250 modular system. Rice husk fiber was morphologically and thermally characterized using scanning electron microscopy (SEM), while its thermal behavior was analyzed by thermogravimetric analysis (TGA) alongside a fire behavior assessment. Additionally, energy simulations were conducted to compare the thermal performance of rice husk fiber with other insulating materials when integrated into a building’s thermal envelope. The results showed an average thermal conductivity of 0.040 W/mK, a U-value of 0.17 W/m²K, and a heating demand of 9.56 kWh/m²-year when applied to the modular system. The material also exhibited good fire resistance, with a smoldering velocity of 3.40 mm/min. These findings highlight rice husk fiber’s potential as a sustainable insulation material for modular construction, contributing to energy efficiency and climate change mitigation. Full article

Background: Ethylenediaminetetraacetic acid-dependent pseudo thrombocytopenia (EDTA-PCTP) is defined as a false in vitro decrease in the platelet count performed in the EDTA tube due to the spontaneous formation of platelet aggregates that prevent a correct count in hematological auto analyzers. The frequency of EDTA-PCTP varies depending on the population studied, ranging from 0.01% to 30.0%. In Chile, although the diagnosis of this condition is performed in clinical laboratories, only a few isolated reports have been described. Objectives: To determine the prevalence of EDTA-PCTP in a cohort of patients who attended an outpatient clinical laboratory in southern Chile over a period of almost 4 years. Methods: A retrospective analysis was conducted using the Laboratory Information System from January 2021 to November 2024 to identify patients with suspected and confirmed cases of EDTA-PCTP. Results: The prevalence rate observed was 0.044% (12 out of 27,480). Additionally, we established that platelet count measurement from the citrate tube at 2–5 h post-sampling was comparable to the platelet count from the EDTA/K2 tube at time 0 (p > 0.05) in these patients. Conclusions: We conclude that a relatively low prevalence of EDTA-PTCP was identified in a population of patients attending an outpatient laboratory in Chile, marking the first report of its kind in our country. Future studies may validate our findings to enhance understanding of EDTA-PTCP, thereby preventing incorrect diagnoses and treatments. Full article

Phase wraparound due to large inter-sensor spacings in multi-channel demixing renders the DUET and AdRess source separation algorithms—known for their low computational complexity and effective speech demixing performance—unsuitable for hearing-assisted living applications, where such configurations are needed. DUET is limited to relative delays of up to 7 samples, given a sampling rate of $F_s=16$ kHz in anechoic scenarios, while the AdRess algorithm is constrained to instantaneous mixing problems. The task of this paper is to improve the performance of DUET-type time–frequency (TF) masks when microphones are placed far apart. A significant challenge in assistive hearing scenarios is phase wraparound caused by large relative delays. We evaluate the performance of a large relative delay estimation method, called the Elevatogram, in the presence of significant phase wraparound. We present extensions of DUET and AdRess, termed Elevato-DUET and Elevato-AdRess, which are effective in scenarios with relative delays of up to 200 samples. The findings demonstrate that Elevato-AdRess not only outperforms Elevato-DUET in terms of objective separation quality metrics—BSS_Eval and PEASS—but also achieves higher intelligibility scores, as measured by the Perceptual Evaluation of Speech Quality (PESQ) Mean Opinion Score (MOS) scores. These findings suggest that the phase wraparound limitations of DUET and AdRess algorithms in assistive hearing scenarios involving large inter-microphone spacing can be addressed by introducing the Elevatogram-based Elevato-DUET and Elevato-AdRess algorithms. These algorithms improve separation quality and intelligibility, with Elevato-AdRess demonstrating the best overall performance. Full article