Search Results (917)

Proton Exchange Membrane Fuel Cells (PEMFCs) are highly valued for their zero emissions, low noise, and environmentally friendly characteristics. However, they face substantial difficulties when starting up in low-temperature conditions. Coolant-assisted heating is usually more effective than other methods because of its fast speed, high heat transfer efficiency, and simple structure. This study developed a three-dimensional multiphase non-isothermal PEMFC cold start model with coolant-assisted heating. Key parameters, including heat consumption rate, coolant flow rate, load current slope, initial membrane water content, catalyst layer porosity, and gas diffusion layer porosity, were selected as optimization variables. A Convolutional Neural Network–Attention Mechanism–Bidirectional Long Short-Term Memory Neural Network (CAB-Net) was employed as a surrogate model to predict the ice volume fraction during the cold start process. The CAB-Net model was further integrated with the Lexicographic Ordered Whale Optimization Algorithm (LO-WOA) to identify the optimal combination of parameters. The optimization aimed to minimize the maximum ice volume fraction (MIVF) in the Cathode Catalyst Layer (CCL) and reduce the energy consumption required to reach this fraction. The optimization results revealed that, compared to the baseline model (MIVF = 0.4519, energy consumption = 0.77264 J), the MIVF was reduced to 0.1471, representing a 67.45% decrease, while energy consumption was reduced to 0.70299 J, achieving a 9.01% decrease. The results underscore the efficacy of the proposed strategy in enhancing cold start performance under low-temperature conditions. Full article

The persistence of latent HIV-1 reservoirs in individuals on antiretroviral therapy (ART) remains a major barrier to cure, necessitating strategies such as “shock and kill” using latency-reversing agents (LRAs). However, current LRAs show limited clinical efficacy, highlighting the need for novel interventions. This study evaluated the in vitro latency-reversing potential of Product Nkabinde (PN) and Gnidia sericocephala using J-Lat A2 (subtype B) and J-Lat C clones T66 and T17 (subtype C) cells. Cell viability was assessed using flow cytometry with Live/Dead dye. Reactivation potential was further tested in combination with established LRAs: panobinostat, SAHA, and TNF-α. G. sericocephala induced dose-dependent latency reversal, with 26.1% of J-Lat A2 and 15.8% of J-Lat T66 cells GFP-positive at 106 µg/mL (p = 0.0001). Co-treatment with LRAs enhanced reactivation—34.6% with SAHA and 87.2% with TNF-α in J-Lat A2 cells, and 56.9% with SAHA and 65.4% with TNF-α in J-Lat T66 cells (p = 0.0001)—while maintaining cell viability above 90%. PN showed minimal activity (≤1.3% GFP-positive) and no effect in combination assays. Fractional inhibitory concentration index analysis revealed no synergistic interactions. Ex vivo, PN and G. sericocephala induced limited increases in HIV-1 gag RNA without substantial cytotoxicity. These findings demonstrate that G. sericocephala effectively reverses HIV-1 latency and potentiates TNF-α-induced reactivation, supporting its potential as a plant-derived LRA for future “shock and kill” HIV-1 cure strategies. Full article

Background/Objectives: The Bedouins (nomads) and the Fellahin (farmers) of Jordan represent two distinct subpopulations, characterized by unique lifestyles, settlement patterns, and linguistic features. This study aims to estimate the frequency of 27 Y-STRs in these two Jordanian subpopulations, along with various forensic parameters and paternal lineage comparisons with neighboring populations. Methods: Twenty-seven Y-STRs were typed in two major Jordanian subpopulations: Bedouin nomads (n = 101) and Fellahin farmers (n = 98). The forensic and paternal genetic lineage parameters and Y-haplogroup predictions were estimated. In addition, we conducted multidimensional scaling (MDS) and centroid analyses based on the Fst distance matrix to compare the sampled communities with neighboring populations from the MENA region, East Africa, Southeast Europe, and South Asia. Results: The Y-haplogroup predictions revealed differences in the predicted lineage composition based on the Y-STR profiles. The predicted J1a2a1a2 haplogroup predominated among the Bedouins (74.3%), whereas the Fellahin displayed a more heterogeneous profile, with notable frequencies of J1 (40%) and J2 (17.3%). Furthermore, the Fellahin exhibited remarkable genetic diversity and significant gene flow, providing plausible evidence of kinship with neighboring Levantine and Arabian groups. In contrast, the Bedouins showed consistently lower diversity across multiple loci, indicating long-term tribal isolation and, therefore, the potential effects of genetic drift. The MDS and centroid analyses positioned the Fellahin among the genetically interconnected Middle Eastern populations, while the Bedouins were clustered with the Arabian Peninsula populations. Conclusions: Overall, the contrasting genetic signatures of the two Jordanian subpopulations reflect their settlement patterns and sociocultural practices. In addition, the Y-STR dataset generated in this study enhances the Jordanian forensic database and to extends our understanding of paternal lineage structures in the West Asian/Levantine region. Full article

Filter cake (or cachaza), a residue generated in the artisanal production of panela, represents an under-explored source of renewable energy in the Ecuadorian Amazon. Valorizing filter cake could reduce the use of solid biomass and emissions associated with traditional combustion. Our objective was to determine the energy potential of the biogas obtained and its contribution to the sustainability of the panela (unrefined cane sugar) production system. A sequential procedure was applied that included the physicochemical characterization of filter cake, feed flow modeling, and stoichiometric simulation under mesophilic conditions. The anaerobic digestion of filter cake with the optimal Composition 6 generated up to 1736.40 m³·day⁻¹ of biogas with 40.7% methane and a calorific value of 14,350 kJ·m⁻³. This was enough to replace 1.24 t·day⁻¹ of wood or 2.38 t·day⁻¹ of bagasse in the production system. This represents an annual saving of 631.08 t of solid biomass, equivalent to conserving 3.63 ha·year⁻¹ of the Amazon rainforest. The Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI) analysis showed impacts on climate change (17.40 kg CO₂ eq/m³) and acidification (0.00516 kg SO₂ eq/m³), attributable to unburned methane and residual H₂S. Meanwhile, the social assessment using the Occupational Health and Safety Potential (OHSP) indicator showed high risks in terms of handling filter cake and cleaning the digestate. Full article

Background/Objectives. Ultraviolet B (UVB) radiation is a key etiological factor for skin cancer, inducing oxidative stress, DNA damage and apoptosis. Nicotinamide (NAM), a NAD⁺ precursor, has shown photoprotective properties, although the mechanisms underlying this effect have not been fully elucidated. This study sought to elucidate the role of NAM in counteracting UVB-induced oxidative damage in HaCaT cells and to assess the contribution of NAD⁺ metabolism to these effects. Methods. HaCaT were exposed to low-dose UVB irradiation (40 mJ/cm²) and treated with NAM (25 μM), alone or in combination with the NAMPT inhibitor FK866 (1 nM) for 4 and 24 h. Oxidative stress, lipid peroxidation and DNA damage were evaluated by DCFDA assay, TBARS assay and comet assay, respectively. Cell proliferation, cell cycle progression and apoptosis were assessed using Ki67 immunofluorescence, flow cytometry analysis and Annexin V/PI staining. Transcriptional activity for oxidative stress- and apoptosis-related markers was analyzed by RT-qPCR. Results. NAM significantly reduced UVB-induced ROS production at both 4 and 24 h post-irradiation in an NAD⁺-dependent manner, as demonstrated by the reversal of its effects following NAMPT inhibition. NAM also decreased oxidative DNA damage accompanied by reduced OGG1 expression, a marker of oxidative stress. Moreover, NAM restored HaCaT proliferation and reduced early apoptosis, particularly at 24 h post-UVB exposure. These protective effects were mediated by NAD⁺. Conclusions. Our results show that NAM confers robust protection to HaCaT cells from UVB-induced oxidative stress and cellular damage, largely mediated by NAD⁺-dependent pathways, supporting its potential role as a systemic photoprotective agent in skin cancer prevention. Full article

Inorganic soil stabilizer represents a promising option to tackle the issues that arise from the land-filling of engineering waste spoil (EWS) due to its economic and environmental benefits. This paper investigates the mechanical and microscopic properties of magnesium oxysulfate soil stabilizer (MOSS) pastes. In addition, the mechanical properties of a novel type of engineering waste spoil-based specimens (EWSS), fabricated using MOSS to solidify high-content EWS, were systematically investigated. The results show that a larger mean particle size and BJH adsorption average pore diameter of LBM were found to accelerate the heat flow rate of the hydration reaction. Specifically, the peak heat flow and total hydration heat attained 30.25 mW/g and 283.9 J/g, respectively, under the condition of an MgO-to-MgSO₄ molar ratio of 9: 1 with LBM2 as the raw material. Furthermore, when the weight ratio of EWS rose from 5% to 80%, the compressive and flexural strengths of EWSS pastes at the 28-day curing age were reduced by 47.0% and 53.3% relative to the reference MOSS pastes. Full article

High-speed jet-in-crossflow (JICF) configurations are central to several aerospace applications, including turbine-blade film cooling, thrust vectoring, and fuel or hydrogen injection in combusting or reacting flows. This study employs high-fidelity direct numerical simulations (DNS) to investigate the dynamics of a supersonic jet (Mach 3.73) interacting with a subsonic crossflow (Mach 0.8) at low Reynolds numbers. Three momentum-flux ratios (J = 2.8, 5.6, and 10.2) are considered, capturing a broad range of jet–crossflow interaction regimes. Turbulent inflow conditions are generated using the Dynamic Multiscale Approach (DMA), ensuring physically consistent boundary-layer turbulence and accurate representation of jet–crossflow interactions. Modal decomposition via proper orthogonal decomposition (POD) and spectral POD (SPOD) is used to identify the dominant spatial and spectral features of the flow. Across the three configurations, near-wall mean shear enhances small-scale turbulence, while increasing J intensifies jet penetration and vortex dynamics, producing broadband spectral gains. Downstream of the jet injection, the spectra broadly preserve the expected standard pressure and velocity scaling across the frequency range, except at high frequencies. POD reveals coherent vortical structures associated with shear-layer roll-up, jet flapping, and counter-rotating vortex pair (CVP) formation, with increasing spatial organization at higher momentum ratios. Further, POD reveals a shift in dominant structures: shear-layer roll-up governs the leading mode at high J, whereas CVP and jet–wall interactions dominate at lower J. Spectral POD identifies global plume oscillations whose Strouhal number rises with J, reflecting a transition from slow, wall-controlled flapping to faster, jet-dominated dynamics. Overall, the results demonstrate that the momentum-flux ratio (J) regulates not only jet penetration and mixing but also the hierarchy and characteristic frequencies of coherent vortical, thermal, and pressure and acoustic structures. The predominance of shear-layer roll-up over counter-rotating vortex pair (CVP) dynamics at high J, the systematic upward shift of plume-oscillation frequencies, and the strong analogy with low-frequency shock–boundary-layer interaction (SBLI) dynamics collectively provide new mechanistic insight into the unsteady behavior of supersonic jet-in-crossflow flows. Full article

Achieving sustainable agricultural intensification in inland valleys while limiting the adverse environmental impacts and uncertainties related to water availability requires an analysis of the long-term hydrological behavior of the catchment. Such a task is particularly challenging in West Africa and Benin due to the limited availability of climate and hydrological data. This study evaluates the applicability of the lumped GR4J model for simulating streamflow in three inland valleys of the Sudanian zone of Benin (Lower-Sowé, Bahounkpo and Nalohou). Additionally, we test the reliability of satellite-based rainfall data (GPM-IMERG, CHIRPS or GSMAP) in modeling hydrological dynamics in these small catchments. The results demonstrate that the GR4J model is effective in simulating daily discharge in the three inland valleys (KGE > 0.5 during both calibration and validation periods), with particularly interesting performance in mean-flow conditions. The modeling using GPM-IMERG and GSMAP rainfall data shows mitigated results with acceptable performance at Nalohou and less accurate results at Bahounkpo and Lower-Sowé. CHIRPS emerged as the most consistent among the evaluated products, providing a sound basis for reconstructing general trends and seasonal variations in historical streamflow time series. The approach of combining historical CHIRPS data and the GR4J model provides insights and can support decision-making related to water resource management in terms of resource capacity and volume in the study area. Except for Nalohou (KGE = 0.19 with GPM-IMERG data), we observe limitations in predicting high flows with satellite-based climatic data at Bahounkpo (KGE = 0.02 with GPM-IR) and Lower-Sowé (KGE = −0.01 with CHIRPS), where the near-zero KGE scores indicate marginal improvement over a mean-flow benchmark. Future work should explore how hybrid or flexible modeling approaches can improve the accuracy of runoff simulations in inland valleys, particularly for extreme (low- and high-) flow conditions. Additionally, the analysis of the trends of indicators of hydrological alteration (IHA) must be deepened in these important ecosystems, especially under climate and land-use change scenarios. Full article

Poly(lactic acid) (PLA) is the most widely used feedstock in material extrusion (MEX) 3D printing. In this study, PLA was combined with 0–40 wt.% of poly(butylene adipate-co-terephtalate) (PBAT) to improve its ductility. The resulting blends were processed into filaments suitable for MEX 3D printing and used to fabricate specimens for mechanical characterization using three distinct raster angles (RAs; 0°, ±45°, and 90°) to statistically evaluate the individual and joint effects of blend composition and raster orientation. Melt flow index (MFI) measurements showed that increasing PBAT content reduced the MFI from 40.4 g/10 min to 34.4 g/10 min, which led to weaker bonding between printed beads, as shown in scanning electron microscopic images. Tensile strength, modulus, and impact strength were evaluated using tensile and Charpy tests. Statistical analysis showed that RA, PBAT concentration, and their interaction all significantly influenced (p < 0.05) mechanical performance. Both strength and modulus decreased as PBAT content and RA increased, with the highest values of 50 MPa and 2.78 GPa observed for neat PLA 3D-printed at 0° RA, and the lowest values of 15 MPa and 1.05 GPa for 40 wt.% PBAT at 90° RA. In contrast, incorporating PBAT improved impact strength, showing its toughening effect. Meanwhile, no clear trend between impact resistance and RA was observed. The highest impact strength (52.7 kJ/m²) was found at 40 wt.% PBAT content and ±45° RA. Full article

Photobiomodulation causes an immediate increase in local blood flow. This study aimed to investigate the effect of 890 nm NIR exposure on local skin blood flow in young and middle-aged healthy subjects. In this placebo-controlled clinical trial, 12 young and 12 middle-aged subjects received either continuous or intermittent NIR exposure (890 nm, 5.1 mW/cm², 4.6 J/cm², and 35.9 J total energy) on the skin of the upper lateral arm. The continuous exposure experiment, performed in young subjects only, applied 30 min of continuous NIR light. The intermittent exposure experiment, conducted in both age groups, applied NIR light through 10 cycles of 3 min NIR exposure and 2 min OFF (for recording blood flow), resulting in a total duration of 50 min. Laser Doppler flowmetry and thermal images were used to monitor local blood flow and skin temperature. In young subjects, continuous NIR exposure significantly increased blood flow for the first 20 min post-exposure compared to placebo. Further, in young and middle-aged subjects, intermittent exposure increased blood flow during the whole exposure period and 15 min post-exposure. In young subjects, blood flow after continuous NIR exposure was significantly higher than intermittent NIR exposure only for the first 10 min. Comparing intermittent exposure between the two age groups, the blood flow was significantly higher in middle-aged subjects. We conclude that NIR PBM increases local skin blood flow in young and middle-aged subjects. The mode of NIR irradiation and the subjects’ age influenced the local skin blood flow response. Full article

This study aims to evaluate the robustness of the well proved Aungier meanline model, originally developed for air and steam turbines, on Organic Rankine Cycles (ORC) turbines. More specifically, the study focuses on two pure-impulse axial turbines with partial admission and using various working fluids, including zeotropic mixtures. To this end, a three-part numerical model was developed to adapt this type of meanline model to a prediction-oriented methodology rather than a design-oriented one. Using inlet and outlet pressures, inlet temperature, and rotational speed as inputs, the model provides the resulting mass flow rate through the turbine as well as its performance characteristics. The model predictions are compared against an extensive experimental dataset comprising more than 300 operating points obtained with three pure fluids—R1233zd(E), NOVEC™ 649, and HFE7000—and three zeotropic mixtures. The model demonstrates good predictive accuracy over a wide range of operating conditions, including very low velocity ratios corresponding to severe off-design operation. Specifically, the mass flow rate is predicted with a Mean Absolute Percentage Error (MAPE) ranging from 1.23% to 3.31%, depending on the working fluid. Furthermore, over an experimental specific work range of 5 to 15 kJ/kg, the predicted numerical work exhibits a MAPE of 7.04% for 102 experimental points corresponding to the main dataset (R1233zd(E)). Finally, the total-to-total efficiency is predicted within ±4 efficiency points, showing a very good trend over a velocity ratio range from 0.06 to 0.36. Full article

Driven by societal and technological progress, the polymer tubing industry is increasingly focused on sustainable and biodegradable products, with polylactic acid (PLA)-based microtubes gaining attention for applications such as medical stents and disposable straws. However, their inherent mechanical limitations, especially under hoop loading and the brittleness of PLA, restrict broader use. Although two-dimensional nanofillers can enhance polymer properties, conventional extrusion only creates uniaxial alignment, leaving fillers randomly oriented in the radial plane and failing to improve hoop performance. To address this, we developed a rotational extrusion strategy that superimposes a rotational force onto the conventional axial flow, generating a biaxial stress field. By adjusting rotational speed to regulate hoop stress, a concentric, interlocked graphene oxide network in a PLA/polybutylene adipate terephthalate microtube is induced along the circumferential direction without disturbing its axial alignment. This architecturally tailored structure significantly enhances hoop mechanical properties, including high compressive strength of 0.54 MPa, excellent low-temperature impact toughness of 0.33 J, and improved bending resistance of 30 N, while maintaining axial mechanical strength exceeding 50 MPa. This work demonstrates a scalable and efficient processing route to fabricate high-performance composite microtubes with tunable and balanced directional properties, offering a viable strategy for industrial applications in medical, packaging, and structural fields. Full article

Background: Short tandem repeats (STRs) are highly variable sequences present along the human genome, including the Y-chromosome. Y-STRs are exclusive to males, and the haplotypes they define are informative. Objectives: Twenty-six Y-STR loci were genotyped in 252 males from Northern Portugal to characterise Y-chromosome genetic variation using the Investigator Argus Y28 QS Kit. Methods: The kit mentioned was used to amplify male DNA samples, and capillary electrophoresis was used to analyze the fragments. Forensic parameters and haplotype diversity were computed, and samples’ haplogroups were predicted. A multidimensional scaling (MDS) plot was used to graphically represent the R_ST genetic distances, including reference populations. Results: A total of 250 different haplotypes were observed, including 248 unique ones, yielding a very high haplotype diversity (HD = 0.999) and discriminatory power (DP = 0.992). Haplogroup analysis indicated a predominance of R1b (58.7%), followed by E1b1b, I and J, pointing to a population history shaped by Mediterranean and North African gene flow. Comparative analysis between Portugal and 5 other populations showed greater genetic affinity with Spain and Italy, while revealing marked differentiation from Greece, Morocco, and former Portuguese colonies. Conclusions: The results confirm that the Northern Portuguese Population exhibits high Y-STR variability and robust forensic resolution. The dataset was submitted to the YHRD database, enhancing the representation of the Portuguese population and underscoring the value of the 26 locus panel for applications in forensic science, genealogy, and population genetics. Full article

Maternal immune tolerance and controlled inflammatory responses are essential for fetal development and successful pregnancy. Regulatory T cells (Tregs) and B cells with regulatory properties (Bregs) maintain this balance by limiting excessive immune activation through the secretion of anti-inflammatory and tolerogenic cytokines, such as IL-10, TGF-β, and IL-35. Moreover, alterations in the costimulatory potential of antigen-presenting cells (APCs), including B cells, modulate the activation and differentiation of T cells. Toll-like receptors (TLRs), particularly TLR9, influence B-cell antigen presentation and cytokine production, thereby affecting the balance between pro-inflammatory and tolerogenic responses at the maternal–fetal interface. TLR9 overexpression has been observed in several pregnancy-related disorders in both humans and murine models. In this study, we examine whether blocking TLR9 shortly after mating could improve pregnancy outcomes and modulate the regulatory and antigen-presenting functions of B cells, as well as their interactions with T cells. Using an abortion-prone murine model (CBA/J × DBA/2J), we show that intraperitoneal administration of a TLR9 antagonist (ODN 2088) shortly after mating increases embryo resorption in CBA/J females compared to controls without affecting implantation. Flow cytometry analysis further reveals that mice receiving the TLR9 antagonist are characterized by downregulation of CD80 and upregulation of CD86 on B cells, accompanied by reduced expression of CD40L and CD28 on T cells, as well as a lower percentage of Tregs and activated T cells. In conclusion, blocking TLR9 signaling shortly after mating does not improve pregnancy outcomes; conversely, it exacerbates pregnancy loss in the CBA/J × DBA/2J abortion-prone model, while altering the costimulatory phenotype of B and T cells and impairing Treg development during pregnancy. Full article

With the expansion of renewable energy deployment, characterized by its variability, stabilizing power and heat supply has become a critical issue. To address this challenge, large-scale and low-cost energy storage technologies are essential, and thermal energy storage (TES) is considered one of the promising solutions. Among large-scale TES systems, Circulating Fluidized Bed TES (CFB TES) is a technology that stores energy as sensible heat in high-temperature sand and utilizes it for power generation using high-temperature steam or steam turbines when needed, offering high compatibility with existing infrastructure. While the underlying circulating fluidized bed system is a well-established technology, precise control of circulating particle flow rates remains a technical challenge due to differences from conventional circulating fluidized beds. In this study, we propose a mechanically simple and thermally durable flow control system that combines an orifice for stepwise flow adjustment and a J-valve (loop seal) for on/off particle transport. In this study, the flow characteristics of the orifice, the minimum fluidization velocity ($u_{mf}$≈ 0.076 m/s), the transient stabilization behavior, and the effects of downstream pressure (back pressure) were evaluated in lab-scale experiments. The results showed that particle flow rate follows a power-law relationship with the orifice diameter, stabilizes when fluidization velocity exceeds $u_{mf}$, and decreases linearly with increasing back pressure. Based on these findings, we established design guidelines incorporating orifice sizing, fluidization control, and back pressure compensation. Full article