Search Results (172)

Droplet freezing on cold surfaces plays a critical role in icing phenomena and thermal management systems. In this study, a numerical model is developed to investigate the freezing of a single water droplet, with emphasis on the influence of natural convection on internal flow dynamics. A two-phase (water–ice) solver is implemented in OpenFOAM by incorporating an enthalpy–porosity solidification model and a buoyancy model into an existing framework. The solver is verified against the analytical solution of the one-dimensional Stefan problem and validated using benchmark cases of natural convection and solidification in a cavity. Using the validated model, we examine the effects of natural convection and water density inversion on the internal flow behavior during droplet freezing. Simulations are performed for a rigid axisymmetric droplet configuration. By accounting for density inversion in the buoyancy source term, the model successfully captures the experimentally observed reversal of internal flow during freezing. The results indicate that the flow reversal occurs when the maximum droplet temperature approaches the density inversion temperature of water. While early-stage freezing follows the classical Stefan solution, comparisons with experimental data indicate that incorporating droplet impact and heat transfer to the surroundings would further enhance the model’s predictive capability. Full article

Background: Metabolic-dysfunction-associated steatotic liver disease (MASLD) is a growing global health burden, yet no approved pharmacological therapy currently exists. Purpose: The purpose of this study is to investigate the prophylactic and therapeutic potential of Rebamipide, a mucosal-protective and anti-inflammatory drug, in a high-fat diet (MHFD)-induced MASLD rat model, integrating quantitative liver proteomics, network analysis, and histopathology. Methods: Male Wistar rats were fed MHFD for 16 weeks and treated with Rebamipide either prophylactically (Reb T1, co-administered with diet) or therapeutically (Reb T2, administered post-NASH onset). Label-free LC-MS/MS proteomics combined with principal component analysis (PCA), partial squares discriminant analysis (PLS-DA), and enrichment analyses (including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Reactome via g: Profiler, network mapping, and Rat Genome Database (RGD) mining) revealed that MHFD had the following impacts: it induced the profound suppression of mitochondrial chaperones (Hspa9), microsomal triglyceride transfer protein (Mttp), and cytochrome P450 isoforms (Cyp2c6); it disrupted lipid trafficking, oxidative stress defense, and xenobiotic metabolism. Results: Rebamipide prophylaxis preserved lipid-handling proteins, prevented glycogen loss, and maintained antioxidant defenses. In contrast, therapeutic administration reversed established steatosis and remodeled metabolic pathways, enhancing fatty acid β-oxidation, detoxification, and mitochondrial protein import. Nine shared proteins across all comparisons, including MTTP and multiple Stress-70 mitochondrial isoforms, mapped to three core genes (Mttp, Cyp2c6, Hspa9) central to lipid transport, protein import, and metabolic stress adaptation. KEGG and Reactome analyses highlighted Rebamipide’s modulation of bile acid synthesis, ceramide and phosphatidylcholine metabolism, lipoprotein remodeling, and MAPK signaling. Histopathological evaluation confirmed Rebamipide’s efficacy, showing reduced steatosis and the normalization of the hepatocyte structure, with near-complete restoration in the therapeutic (Reb T2) group compared to partial protection in the Reb T1 group. Conclusions: These findings demonstrate Rebamipide’s dual-phase, multi-targeted mechanism: early protection against diet-induced metabolic injury and robust reversal of established MASLD pathology. The identified protein triad (Mttp, Cyp2c6, Hspa9) and associated pathways provide novel biomarker candidates and mechanistic insight supporting Rebamipide’s repurposing as a therapeutic for metabolic liver disease. Full article

Channel pruning enables model acceleration by removing channels from convolutional neural networks (CNNs). However, many existing methods adopt a “hard removal” strategy that directly removing low-importance channels, leading to severe feature loss and accuracy degradation. To address this issue, we propose Reconstruction and Consolidation Pruning (RCP), a pruning framework that decouples the pruning process into a pruning-training phase and an inference phase. During pruning training, RCP generates a pruning strategy based on channel importance under a global pruning rate constraint, and constructs a feature reloading mechanism. This mechanism utilizes a learnable $1\times 1$ compensation convolution to adaptively transfer and fuse discriminative features hidden in the pruned channels into the retained channels. In the inference phase, RCP adopts a linear reparameterization strategy to seamlessly consolidate the compensation branches into the main network branch without loss of performance, ensuring zero additional operator overhead during inference. This reversible structural transformation ensures that the training-time augmented architecture and the inference-time compact architecture are functionally identical under linear consolidation. Experimental results show that at 50% FLOPs reduction, RCP incurs only a 0.84% accuracy drop on ResNet-50 (ImageNet-1K), while at 53% FLOPs reduction it achieves a 0.07% accuracy improvement for ResNet-56 (CIFAR-10), validating the proposed method’s effectiveness and superiority under high compression rates. Full article

Background/Objectives: The increasing prevalence of antimicrobial-resistant bacteria highlights the need for improved methodologies to evaluate antimicrobial activity beyond conventional minimum inhibitory concentration testing. While resazurin-based assays are widely used for minimum inhibitory concentration determination due to their simplicity and sensitivity, minimum bactericidal concentration assessment still relies on labor-intensive colony-forming unit counting. The objective of this study was to develop and validate a resazurin-based microwell assay capable of determining both the minimum inhibitory concentration and the minimum bactericidal concentration without routine plate counting, thereby simplifying bactericidal evaluation. Methods: A two-step resazurin-based fluorescence assay was designed and performed in microplates. After determining the minimum inhibitory concentration using resazurin as a metabolic indicator, well-showing inhibited bacterial growths were subjected to a regrowth phase by transferring aliquots into fresh antimicrobial-free medium containing resazurin. This additional step allowed discrimination between reversible metabolic inhibition and irreversible bacterial death. The method was evaluated using ciprofloxacin and chloramphenicol against four bacterial species: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa. Minimum bactericidal concentration values obtained using this assay were compared with those obtained through conventional colony counting on agar plates. Results: Minimum bactericidal concentration values obtained using the two-step fluorescence assay were fully concordant with the conventional colony-forming unit counting method for all tested antibiotics and bacterial species. Conclusions: The proposed two-step resazurin-based microwell assay represents a rapid, reliable, and less labor-intensive alternative for the determination of both the minimum inhibitory concentration and the minimum bactericidal concentration, with potential applications in clinical and industrial microbiology laboratories. Full article

In this study, a highly crystalline 2H (hexagonal)-phase MoS₂ sensing layer with a precisely controlled crystal structure was realized through a combination of DC sputtering and sulfurization annealing processes, and subsequently integrated with a D-shaped optical fiber to develop a highly sensitive carbon dioxide (CO₂) sensor. Conventionally sputtered MoS₂ thin films often suffer from the presence of unstable metallic 1T (tetragonal) phases and a high density of sulfur vacancies, which significantly degrade sensor reversibility and long-term stability. Here, high-temperature annealing under a sulfur-rich atmosphere was employed to induce a complete phase transition from the metastable 1T phase to the stable semiconducting 2H phase, while simultaneously healing sulfur vacancies. Enhanced crystallinity was confirmed by Raman spectroscopy. The fabricated sensor exhibited excellent linearity (R² > 0.99) and markedly improved repeatability over a CO₂ concentration range of 1000–10,000 ppm. This significant performance enhancement is attributed to reversible charge transfer induced by sulfur vacancy passivation, which modulates the complex refractive index of the MoS₂ layer and optimizes optical interaction with the evanescent field of the D-shaped fiber. The phase engineering and defect-healing strategy presented in this work effectively addresses the drift issues commonly observed in conventional electrical gas sensors and provides a crucial pathway toward the realization of high-performance optical gas sensors. Full article

Lutein and zeaxanthin are macular carotenoids known for their protective role against major eye diseases. The bio-accessibility of these macular carotenoids is extremely low, with a limited amount synthesised in plants. Quantifying these compounds in plants/biological samples is challenging because of their structural similarity. Although numerous methods have been reported for quantifying macular carotenoids, there is currently no unified chromatographic technique that can be applied for the separation and quantification of these carotenoids across diverse matrices over a broad dynamic range while also incorporating an effective extraction step. Biochemical processes during digestion and absorption further lower carotenoid levels in the body (bioavailability), making precise measurement of their esterified forms necessary. Here, we incorporate an alkaline hydrolysis extraction and present a single liquid chromatographic method applicable to both PDA and MS detection for the separation and quantification of lutein and zeaxanthin across various matrices (food, digesta, and Caco-2 cells) and concentration ranges. It utilises common solvents for the mobile phase system and a C30 column. The reverse-phase method achieved excellent recoveries in spiked samples, acceptable relative standard deviations (RSDs) for validation parameters, and offers potential for high-throughput analysis while being transferable between matrices (from plant to Caco-2 cells). Full article

As a key technology for achieving building heating electrification and decarbonization, the air-source heat pump (ASHP) has long been constrained by outdoor heat exchanger frosting in cold and humid regions. Frosting leads to increased thermal resistance, a sharp rise in air-side pressure drop, and the attenuation of heating capacity, while traditional active defrosting methods, such as reverse-cycle defrosting, suffer from high energy consumption and heating interruption. This review aims to systematically present the recent research progress of superhydrophobic surfaces (SHSs) as a highly efficient passive anti-frosting strategy. First, the complex phase-change dynamics of frosting and key influencing factors such as environment and surface characteristics are deeply analyzed. Second, it elucidates how superhydrophobic surfaces achieve delayed frosting and sloughing off defrosting by delaying nucleation, promoting droplet self-removal, and reducing ice adhesion. Furthermore, fabrication processes suitable for complex fin structures are systematically reviewed from the perspectives of subtractive manufacturing, in situ growth, and additive coatings, and their industrialization prospects are compared. Finally, the practical effects of this technology in improving heat transfer coefficients, reducing fan energy consumption, and improving defrosting efficiency are evaluated. Although superhydrophobic technology has significant energy-saving potential, it still faces challenges such as poor long-term durability, wettability failure under extreme conditions, and residual micro-droplets. Future research should focus on the development of highly durable materials, the matching design of micro–nano structures with macro flow channels, and active–passive synergistic anti-frosting strategies. Full article

The synthesis of enantiomerically pure chiral β-nitroalcohols is a crucial objective in asymmetric catalysis. In order to efficiently obtain such chiral products, we developed a series of thermoresponsive, oxazoline–copper catalysts (Cu^II-PN_xFe_yO_z) via sequential reversible addition–fragmentation chain transfer (RAFT) polymerization. These catalysts can self-assemble in water into single-chain nanoparticles (SCNPs) with biomimetic behavior, in which intramolecular hydrophobic and metal-coordination interactions generate a confined hydrophobic cavity. Comprehensive characterization by FT-IR, TEM, DLS, CD, CA, and ICP analysis confirmed the nanostructure and composition. When applied to the aqueous-phase asymmetric Henry reaction between nitromethane and 4-nitrobenzaldehyde, the optimal catalyst (2.0 mol%) achieved a quantitative yield (96%) with excellent enantioselectivity (up to 99%) within 12 h. Furthermore, the thermosensitive poly(N-isopropylacrylamide, NIPAAm) block enabled facile catalyst recovery through temperature-induced precipitation above its lower critical solution temperature (LCST). This work presents an efficient and recyclable biomimetic catalytic system, offering a novel strategy for designing sustainable chiral catalysts for green organic synthesis. Full article

Background/Objectives: Dual stimulation starting in the follicular phase allows retrieval of more oocytes than single follicular-phase controlled ovarian stimulation (COS). However, dual stimulation excludes fresh embryo transfer (ET), forcing us to postpone the first ET. If dual stimulation is performed in a reverse way (“reverse”-dual stimulation, R-DS), fresh ET can be performed, potentially reducing the time to pregnancy. The aim of the present study is to investigate reproductive outcomes of R-DS compared to two consecutive COS starting in the follicular phase (2FP-COS). Methods: A retrospective study was performed on 146 poor responders matching Bologna criteria, among which 45 underwent R-DS and 101 received 2FP-COS. In the R-DS group, the first COS began 5 days after ovulation and the second 5 days after oocyte retrieval. The primary outcome was the time to pregnancy. Results: In R-DS, stimulation length, retrieved oocytes, and blastocyst formation rate were comparable in the luteal and follicular COS rounds. Circulating progesterone was always <1.0 ng/mL at ovulation trigger, and fresh ET was performed with a mean endometrial thickness of 9.27 ± 2.28 mm. Comparing R-DS and 2FP-COS, no differences were found in terms of retrieved oocytes and cumulative live birth rate; however, the R-DS group showed significantly shorter time to pregnancy (52.9 ± 11.6 vs. 103.2 ± 23.2 days, p < 0.05). Conclusions: This study suggests that R-DS is not inferior to two consecutive COS starting in the follicular phase in terms of oocytes retrieved and cumulative live birth rate. R-DS allows immediate fresh ET and can significantly shorten the time to pregnancy, a relevant issue for poor responders’ patients. Full article

Herein, we report the synthesis via controlled reversible addition-fragmentation chain transfer (RAFT) polymerization of amphiphilic 2-vinylpyridine-b-styrene (2VPy-b-Sty) diblock copolymers of high molar masses (range: 52,100–304,000 g mol⁻¹) and various compositions (range: 2VP content 11.6–59.2 mol%) and their use for the fabrication of nanoporous membranes. The successful synthesis of the amphiphilic diblock copolymers was confirmed through the characterization of their molar masses, molar mass distribution, and composition using GPC and ¹H-NMR spectroscopy, respectively. Subsequently, membranes of the diblock copolymers were fabricated following the “phase inversion” technique. The resulting membranes were characterized via scanning electron microscopy which revealed the presence of sphere percolation networks morphology for all diblock copolymers with M_n ranging from 120 to 300 kDa and 2VPy content between 10 and 15 mol% at the optimal conditions. Afterward, the developed membranes were evaluated in terms of their permeability towards water and in terms of their ability to retain two different microorganisms, namely, Enterococcus faecalis and Escherichia coli, that are known to be harmful to human health. The experimental water flux for a membrane with pore size around 60 nm was equal to 31,400 L h⁻¹ m² and expectedly decreased with the decrease in membrane pore diameter. The retention ability of membranes for Enterococcus faecalis and Escherichia coli was higher than 90%. In particular, the retention ability for Enterococcus faecalis was equal to 98.9% and for Escherichia coli was 91.4%. The toxicity of the produced membrane was also determined, and the measured value was relatively low, at 17%. Full article

This work presents results on laser-induced fabrication of metal and oxide structures on glass substrates. The Laser-Induced Reverse Transfer (LIRT) technique is applied using Zn and Sn, sintered ZnO and SnO₂, and oxide composite targets. The processing is performed by nanosecond pulses of a Nd:YAG laser system operated at wavelength of 1064 nm. Detailed analyses of the deposited material morphology, composition and structure are presented, as the role of the processing conditions is revealed. It is found that at the applied conditions of using up to five laser pulses, the deposited material is composed of a nanostructured film covered in microsized nanoparticle clusters or droplets. The use of metal targets leads to formation of structures composed of metal and oxide phases. The adhesion test shows that part of the deposited material is stably adhered to the substrate surface. It is demonstrated that the deposited materials can be used as resistive gas sensors with sensitivity to NH₃, CO, ethanol, acetone and N₂O, at concentrations of 30 ppm. The ability of the method to deposit composite structures that consist of a mixture of both investigated oxides is also demonstrated. Full article

Yttrium–magnesium alloys are commonly employed as processing additives in magnesium alloy materials. Incorporating yttrium into magnesium alloys via Y-Mg intermediate alloys not only minimizes oxidation and burn-off loss but also simplifies operational procedures. Utilizing yttrium–magnesium alloys ensures a stable composition and reliable quality of magnesium alloy products, while contributing to reduced production costs and minimized environmental pollution. In this study, a molten salt co-reduction method was developed for the preparation Y-Mg intermediate alloys. The electrochemical co-reduction behaviors of Y(III) and Mg(II), as well as the transient states of Y-Mg intermediate alloys, were systematically investigated by transient electrochemical techniques. Results indicated that the reduction of Y(III) at the molybdenum (Mo) cathode is a reversible electrochemical process, whereas the reduction of Mg(II) is irreversible and diffusion-controlled. The diffusion coefficient of Y(III) and Mg(II) in the fluoride salt at 1000 °C were determined to be 3.98 × 10⁻⁵ cm²/s and 1.16 × 10⁻³ cm²/s, respectively. Electrochemical calculations revealed that the reduction of Y(III) involves a single-step transfer of three electrons, while Mg(II) involves a single-step transfer of two electrons. The corresponding electrode reactions are Y(III) + 3e⁻→Y and Mg(II) + 2e⁻→Mg, respectively. A Y-Mg alloy sample prepared by constant-current molten salt electrolysis primarily consists of the MgY phase with a composition of 88.38 wt% yttrium and 11.62 wt% magnesium. Full article

Layered transition-metal oxides are among the most promising sodium-ion battery cathodes owing to their high specific capacities and structurally tunable frameworks. However, the prototypical P2-Na_0.67Ni_0.33Mn_0.67O₂ (NM) undergoes an irreversible P2 → O2 phase transition at high voltages, accompanied by severe lattice strain and capacity fade, which hinders practical deployment. Here, we propose a cooperative regulation strategy that couples Zn/Al co-doping with Na enrichment, and successfully synthesize P2-Na_0.80Ni_0.14Zn_0.14Mn_0.58Al_0.14O₂ (NMZA-N14). The optimized NMZA-N14 delivers an initial discharge capacity of 125 mAh g⁻¹ at 0.1C and demonstrates exceptional cycling and rate performance, retaining 98.6% of its capacity after 100 cycles at 0.2C and 93.6% after 200 cycles at 1C. Kinetic analyses indicate a higher Na⁺ diffusion coefficient and a lower charge-transfer resistance in NMZA-N14, evidencing substantially accelerated ion transport. In situ X-ray diffraction further reveals a reversible P2 → OP4 phase transition in the high-voltage regime with a unit-cell volume change of only ~2.27%, thereby avoiding the irreversible structural degradation observed in NM. This synergistic modulation markedly enhances structural stability and electrochemical kinetics, providing a viable pathway for the rational design of high-performance sodium-ion battery cathodes. Full article

Catalytic upgrading of bioethanol via a C–C coupling reaction is a sustainable method of producing 1-butanol, a high-performance biofuel. This reaction was studied using a flow-through microreactor system with Pd/MgO-Al₂O₃ and bimetallic Pd-Cu/MgO-Al₂O₃ mixed oxide-based catalysts in a H₂ carrier gas at a pressure of 21 bar and temperatures ranging from 200 to 350 °C. The effect of the metal promoter(s) on the hydrogen transfer reaction steps in the overall reaction was investigated. The palladium promoter significantly improved the activity and butanol selectivity across the entire temperature range. However, the yield of liquid products decreased significantly at temperatures higher than 250 °C, primarily because the decarbonylation side reaction of the acetaldehyde intermediate accelerated. The promoting effect of Pd was most beneficial below 250 °C because the decarbonylation reaction was inhibited by the reversible poisoning effect of CO on multiple Pd sites responsible for decarbonylation. Diluting the Pd phase with Cu increased liquid yields due to gradually decreasing decarbonylation activity. However, the dehydrogenation–hydrogenation activity decreased as well, as did the promoting effect on the corresponding reaction steps in the coupling reaction. Additionally, the product distribution changed dramatically, decreasing 1-butanol selectivity, because metallic Cu can catalyze the formation of ethyl acetate and ketone products. Full article

Distributed coherent synthesis on dynamic platforms suffers from phase misalignment and significantly reduced synthesis efficiency due to navigation errors and communication delays. To address this challenge and dramatically enhance the synthesis efficiency, this paper proposes an “error-performance” quantification framework and corresponding compensation methods: (1) Phase compensation strategy: Adaptive Kalman Filter (AKF) with a multi-index fusion-based adaptive factor derived from novelty sequences, enabling intelligent switching between predictive and robust modes for improved phase compensation; (2) Positioning error modeling method: Employing an adaptive reverse-adaptive robust Kalman filter (ARKF) to synthesize error trajectories, with standard deviation σ as the primary control parameter. Monte Carlo simulations establish a quantitative relationship between positioning error standard deviation (σ) and coherent synthesis success rate: Under a 3-transmitter configuration, success rate ≥ 95% when σ ≤ 100 mm; The 100–237.3 mm range constitutes a transition zone where success rate decreases from 95% to 80%; when σ ≥ 460 mm, the success rate stabilizes at 56–58%. The core conclusion indicates that when σ ≤ 237.3 mm, the system achieves high coherent synthesis efficiency with 80% probability. This paper aims to establish a cross-platform transferable error-performance quantification framework, providing a direct reference for navigational accuracy selection in distributed coherent systems. Full article