Search Results (6,713)

Ulcerative colitis (UC) is a chronic inflammatory disease characterized by persistent colonic inflammation, excessive oxidative stress, and impaired barrier function. Transition metal-based nanoparticles offer promising antioxidant platforms to address oxidative stress-related pathologies. To overcome the poor gastrointestinal stability of the potent dietary antioxidant epigallocatechin gallate (EGCG), we utilized zinc-coordinated EGCG (EGCG-Zn) nanoparticles (NPs), which function as a transition metal–phenolic network, to achieve sustained colonic release and overcome the poor gastrointestinal stability of free EGCG. The therapeutic efficacy and underlying mechanisms were evaluated in dextran sulfate sodium (DSS)-induced colitis in mice. Oral administration of EGCG-Zn NPs effectively reduced oxidative stress, suppressed pro-inflammatory cytokine production, alleviated colitis symptoms, and repaired the intestinal mucus and mechanical barriers. Mechanistically, transcriptomic analysis revealed that EGCG-Zn NPs pretreatment markedly reversed DSS-induced transcriptional alterations. Integrated K-means clustering and KEGG enrichment analyses further demonstrated that these protective effects were mediated by down-regulating inflammation-associated genes and up-regulating tight junction proteins, primarily involving the modulation of calcium signaling, T-cell differentiation, and the PI3K-Akt, Wnt, NF-κB, and TNF pathways. Collectively, these findings suggest that EGCG-Zn NPs alleviate DSS-induced colitis by mitigating inflammation, suppressing oxidative stress, and promoting epithelial barrier repair, supporting their potential as a functional nutraceutical for UC management. Full article

This paper describes the synthesis, characterization and application in hydrogenation catalysis of triphenylphosphine-stabilized palladium and rhodium species on SBA-15. The materials were achieved by synthesizing a triethoxysilyl-functionalized triphenylphosphine ligand through the reaction of (2-chloromethylphenyl)diphenylphosphine and (3-mercaptopropyl)triethoxysilane. Treatment of this ligand with the appropriate palladium(II) and rhodium(I) complexes produced the corresponding transition metal complexes, which were then immobilized on the support material. The final catalysts were obtained by treating these precursor materials with dihydrogen at elevated temperatures. These catalysts are highly active in the hydrogenation of a wide range of olefins under mild conditions. XPS studies on one of the palladium catalysts reveal that only a part of the metal is reduced, with almost no further reduction of the remaining palladium(II) species observed after tenfold recycling and reuse of the material. Full article

This review aims to analyze defect-driven thermoelectric decoupling in pulsed laser deposition (PLD)-grown oxygen-deficient ${WO}_x$ and tungsten Magnéli thin films. While transition metal oxides offer a non-toxic, abundant alternative to conventional thermoelectrics, tungsten oxide stands out due to the profound impact of sub-stoichiometry on its transport properties. We systematically evaluate how ordered oxygen vacancies and crystallographic shear planes transform insulating ${WO}_3$ into sub-stoichiometric phases exhibiting metallic-like conductivity. Specifically, we analyze how the delocalization of W$5d$ electrons around defect-rich regions induces electronic states near the Fermi level, decoupling the Seebeck coefficient from electrical conductivity. Simultaneously, we discuss how these engineered defect networks and shear planes selectively enhance phonon scattering, drastically suppressing lattice thermal conductivity without hindering electronic transport. By establishing PLD as an effective approach for precise oxygen stoichiometry and defect architecture control, this review highlights the high-temperature potential of tungsten Magnéli phases and outlines future pathways to maximize their thermoelectric figure of merit ($ZT$). Full article

We propose an absorber composed of graphene and vanadium dioxide (VO₂). The phase transition of VO₂ enables dynamic switching of the absorption response between a single broadband state and three narrowband states. The results indicate that when VO₂ changes to the metallic state, the absorber exhibits triple narrow band absorption. When VO₂ is in the dielectric phase, the absorber demonstrates single broadband absorption. The absorption can be regulated through the Fermi energy level (E_F) of graphene. Furthermore, the proposed absorber exhibits polarization-independent characteristics and maintains stable absorption performance under wide-angle oblique incidence. The absorber also has high refractive index sensitivity. Impedance matching theory is employed to investigate the physical mechanism governing the absorber. The tuning principle of the device was analyzed and verified successfully by using an equivalent circuit model (ECM). Full article

Ultrashort pulse mode-locked fiber lasers demonstrate significant application potential in optical communication, precision measurement, and ultrafast photonics. As the critical component for pulse generation, the performance of saturable absorbers directly dictates the output characteristics of these lasers. To address the limitations of traditional saturable absorbers regarding operating bandwidth, fabrication cost, and environmental stability, two-dimensional transition metal dichalcogenides represented by molybdenum disulfide have emerged as research hotspots in the field of novel saturable absorbers due to their broadband tunability, superior nonlinear optical response, and flexible fabrication processes. This review focuses on molybdenum disulfide saturable absorbers and systematically summarizes their nonlinear optical properties, mainstream fabrication strategies, and recent application progress in mode-locked fiber lasers. Furthermore, the advantages and challenges concerning key performance metrics such as pulse stability, output power, and pulse duration are comprehensively evaluated. Finally, future perspectives on critical issues including fabrication process optimization, long-term stability enhancement, and composite structure design are discussed. This work aims to provide theoretical references and technical support for the practical application of high-performance ultrashort pulse fiber lasers. Full article

The adsorption behavior of selected volatile sulfur compounds on graphene was examined using density functional theory. The analytes of interest are hydrogen sulfide, methyl mercaptan and dimethyl sulfide, which are found in the exhaled breath of halitosis patients. The human breath contains several volatile compounds that act as chemical fingerprints of what is happening inside the body. This study employs first-principles calculations to investigate the structural, electronic, and adsorption properties of pristine and transition-metal-doped graphene (Fe, Ru, and Os) for the detection of key volatile sulfur compounds relevant to breath analysis and halitosis screening. According to our findings, when a single carbon atom is substituted with an iron, ruthenium or osmium atom in the optimized graphene sheet, which is equivalent to a dopant concentration of 2 mol% in experiments, the adsorption behavior of the system is altered significantly. Based on the resultant adsorption behavior and electronic structure alterations, important sensor properties were examined. This work presents a non-invasive approach for halitosis detection, therapeutic monitoring, and metabolic status observation by analyzing the volatile sulfur compounds present in exhaled breath. Additionally, this study demonstrates how computational modeling can be used as a decision support tool. Full article

Hydrogen-rich compounds under high pressure are promising for high-temperature superconductivity, but many high-$T_{\mathrm{c}}$ hydrides rely on rare-earth or alkaline-earth elements and remain difficult to tune chemically. Transition-metal hydrides offer an alternative platform because partially filled d states can modify the electronic density of states, metal–hydrogen hybridization, and electron–phonon coupling. Here, ${\mathrm{VH}}_3$ is used as a parent high-pressure transition-metal hydride framework, and Ti substitution is introduced as a chemically compatible way to tune the d-derived states near the Fermi level. Two ternary hydrides, ${\mathrm{Ti}}_3{\mathrm{VH}}_{12}$ and ${\mathrm{TiV}}_3{\mathrm{H}}_{12}$, are therefore constructed from the ${\mathrm{VH}}_3$ lattice and investigated by first-principles calculations at 200 GPa. Both compounds are thermodynamically and dynamically stable under this pressure condition, as indicated by formation energies, the Ti–V–H convex hull, and phonon spectra. Within the same ultrasoft-pseudopotential computational framework, ${\mathrm{Ti}}_3{\mathrm{VH}}_{12}$ and ${\mathrm{TiV}}_3{\mathrm{H}}_{12}$ yield Allen–Dynes $T_{\mathrm{c}}$ values of 42.1 K and 36.8 K, respectively, higher than the corresponding ${\mathrm{VH}}_3$ value. A norm-conserving cross-check for ${\mathrm{VH}}_3$ gives a different absolute value, indicating that the $T_{\mathrm{c}}$ estimates are method-dependent. Electronic structure analysis indicates that Ti incorporation shifts pronounced van Hove singularities close to the Fermi level, enhances the density of states, and changes the Fermi surface topology. These results suggest that Ti–V–H hydrides are a useful model system for examining how transition-metal substitution can couple structural stability with electronic tuning in compressed hydride superconductors. Full article

Exhaust gas temperature is a critical indicator of combustion efficiency and waste heat recovery in regenerative aluminum smelting furnaces, directly governing the energy intensity and carbon footprint of secondary aluminum production—a cornerstone of the circular economy. However, accurate prediction is challenged by pronounced long-range thermal lag and dynamically evolving spatial dependencies among process variables during operational transitions, which hinder real-time process optimization for energy savings. To address these challenges and advance sustainable manufacturing, a novel prediction model termed ChronoClassGAT (Chronological Class-aware Graph Attention Network) is proposed in this paper. The model integrates three key components: (1) a Temporal Convolutional Autoencoder (TCN-AE) with a Gaussian Mixture Model (GMM) for unsupervised identification of distinct operating regimes, providing categorical priors for dynamic graph construction; (2) a multi-graph fusion mechanism that builds operating-condition-specific spatial structures, enabling a Graph Attention Network (GAT) to adaptively model evolving inter-variable dependencies; and (3) a ChronoSwish activation function that modulates LSTM-based temporal encoding with time-aware periodic and switching signals, enhancing responsiveness to transient dynamics. Validated on real-world industrial datasets, ChronoClassGAT achieves superior prediction accuracy (RMSE of 2.2712, MAE of 1.8023, and $R^2$ of 0.9985) over state-of-the-art baselines. By enabling precise and robust exhaust gas temperature forecasting, our framework provides the decision-support intelligence needed for optimizing regenerator switching, minimizing thermal losses, and reducing fuel consumption, thereby contributing significantly to the operational energy efficiency and environmental sustainability of the energy-intensive non-ferrous metal industry. Full article

Accurate characterization of the Bauschinger effect is essential for improving springback prediction in simulations of complex sheet-metal components. However, in-plane tension–compression tests are prone to compressive instability and wrinkling during reverse loading, and the selection of clamping force still lacks a theoretical basis. In this study, a critical clamping force prediction model was developed based on energy conservation and the Cao–Boyce instability criterion. The model establishes the relationship between the critical clamping force, material strength coefficient, strain-hardening exponent, specimen geometry, and effective support area. Finite element simulations and experiments were conducted to investigate the contact state, local support effect, and instability-mode transition of Q890 high-strength steel, 2A14 aluminum alloy, and 304 stainless steel under different clamping forces. For Q890 steel, the critical clamping force interval was 900–1000 N, within which the compressive instability strain increased from nearly 0 to 0.085 and the instability mode changed from single-wave to double-wave buckling. After calibrating the boundary correction coefficient using Q890 steel, the predicted critical clamping forces for 2A14 aluminum alloy and 304 stainless steel were 594 N and 278 N, respectively. The optimized clamping forces enabled smooth cyclic tension–compression curves. Full article

Two-dimensional transition metal dichalcogenides are being studied as channel materials for beyond-silicon electronics because their atomic-scale thickness enables strong electrostatic control. Among these materials, tungsten diselenide (WSe₂) is particularly attractive because it exhibits ambipolar transport. Despite this advantage, practical WSe₂ transistors remain constrained by Fermi-level pinning at metal contacts, contact-dominated carrier injection, and defect-induced variability, making controlled doping a central issue. This review examines doping strategies developed for WSe₂, focusing on methods compatible with atomically thin van der Waals semiconductors. The discussion covers surface charge-transfer doping by molecular adsorbates, Lewis acids, and alkali metals, as well as defect-mediated chemisorption, self-limiting oxide interfacial layers, and in situ vacancy engineering during growth. Particular attention is given to the thermodynamic mechanisms of charge transfer, the distinction between contact-selective and channel-selective doping, and the trade-offs between degenerate and non-degenerate doping. The effects of doping are also discussed, including contact-resistance reduction through Schottky-barrier narrowing, threshold-voltage control, apparent mobility enhancement through impurity screening and defect passivation, and thermal and temporal stability. The review further summarizes how controlled doping has enabled complementary metal-oxide-semiconductor logic circuits and identifies the remaining challenges in air stability, selective-area patterning, scalable synthesis, and low-temperature integration for monolithic three-dimensional electronic devices. Full article

Oxidative stress is a central mechanism underlying the toxicity of fine particulate matter (PM_2.5); however, the source-specific chemical drivers of particle-associated oxidative potential remain incompletely understood. In this study, the oxidative potential (OP) of ambient PM_2.5 in Xi’an was investigated during winter and summer using the dithiothreitol (DTT) assay, with particular emphasis on the toxicological roles of water-soluble metals and emission sources. PM_2.5 exhibited significantly higher volume-normalized OP (DTT_v) in winter, indicating an enhanced particle-associated oxidative stress burden during the heating period. Notably, although water-soluble metals accounted for only a minor fraction of PM_2.5 mass, interpretable machine learning analysis (XGBoost–SHAP) identified potassium and manganese as dominant contributors to OP, highlighting the importance of biomass burning tracers and redox-active transition metals in particle-mediated reactive oxygen species generation. Source apportionment further revealed pronounced seasonal contrasts: dust sources contributed substantially to wintertime OP primarily due to their large mass loading, whereas traffic-related emissions dominated OP in summer owing to their high intrinsic oxidative toxicity. Overall, these findings suggest that variations in PM_2.5 oxidative potential are more closely associated with chemical composition and source-specific oxidative activity than with particle mass alone, providing additional insight into the factors influencing PM-related health risks. Full article

Rice glutelin hydrolysates (RGHs) with different degrees of hydrolysis (DH) were prepared using papain, and the structural characterization, physicochemical stability, and antioxidant activity of RGH were analyzed. Results showed that RGH primarily consisted of low molecular weight (MW) peptides (<3 kDa), with hydrophobic/aromatic amino acid content increasing with DH. Higher DH level led to reduced average particle size and zeta potential of RGH. Structurally, as DH increased, a decrease in α-helix content alongside increased β-sheet/random coil ratios was observed in RGH, indicating a transition towards a more disordered structure in RGH. Furthermore, the antioxidant activity of RGH was significantly enhanced with the increase in DH, with RGH-18 showing the highest bioactivity. RGH maintained stability and antioxidant capacity under gastrointestinal digestion as well as various environmental stresses, including varying pH and temperatures, and the presence of metal ions. Cellular experiments demonstrated that RGH-18 alleviated H₂O₂-induced oxidative damage in HepG2 cells, likely by inhibiting Keap1 and activating Nrf2 via the Keap1/Nrf2 pathway. This study supports the potential of RGH as a functional ingredient and provides insights for targeted rice peptide production. Full article

When metal oxides are employed as anodes in lithium-ion batteries, their practical application is often constrained by sluggish reaction kinetics. Structure optimization and heterointerface regulation are effective strategies for improving the aforementioned issue. Herein, a series of Co₃O₄/ZnCo₂O₄ heterostructured materials with hollow structures is prepared. The effects of the two-phase ratio on the interfacial activity and electrochemical performance are systematically investigated. Among them, the optimized Co₃O₄/ZnCo₂O₄-2 material exhibits enhanced interfacial interactions and abundant oxygen vacancies, which optimize the local electronic environment and facilitate charge transfer. Electrochemical test results indicate that the Co₃O₄/ZnCo₂O₄-2 anode maintains a reversible capacity of 582.4 mAh g⁻¹ after 1000 cycles at 1 A g⁻¹, demonstrating good cycling stability. Furthermore, the full cell assembled with a LiFePO₄ cathode maintains a discharge capacity of 115.9 mAh g⁻¹ after 100 cycles at 0.2 C, validating the practical application potential of the material. This work reveals the key role of interface regulation in boosting Li⁺ diffusion kinetics of transition metal oxides, providing new insights for the rational design of heterostructured anodes. Full article

This study investigates the environmental potential and viability of replacing natural river aggregates (RAs) with copper slag aggregates (CSAs) in concrete production. The primary objective was to assess the structural performance of these eco-concrete mixtures and determine the optimum copper slag content for structural applications. The experimental program evaluated concrete mixtures with natural river aggregate replacement levels of 20% + 20% and 50% + 100% for the 8/16 mm and 16/32 mm fractions, respectively, using coarse copper slag aggregate (CCA). The results indicate that incorporating CCA increases concrete compressive strength, successfully meeting the requirements for strength class C25/30. The petrographic assessment indicated a shift towards an aggregate mixture, in which the dominant quartzite and a constant quartz-mineral fraction of 16.5% provide a stable structure alongside the CSA grains. However, a significant increase in water penetration depth (up to 22%) was observed, highlighting the enhanced water penetration depth of these concretes. SEM microstructural analysis attributed the improved bond between the cement matrix and CCA grains to a compact interfacial transition zone. Additionally, leaching tests confirmed that heavy metals are effectively immobilized in the cement paste for mixtures with lower replacement levels (up to 20%), thereby meeting environmental standards. The study concludes that copper slag at these controlled replacement levels represents a sustainable, high-quality alternative for construction materials in drainage infrastructure. Incremental analysis in accordance with NEN 7375 showed that the tested material behaves as an insoluble matrix, with no evidence of diffusion-controlled leaching. The cumulative leaching values obtained after 64 days of testing in accordance with NEN 7375 were significantly below the regulatory limits for all components analyzed. These findings indicate a low potential for contaminant release and favorable environmental stability of the 20% replacement mixture, though further leaching evaluation is required for maximum slag contents. Full article

Diffusion solidification is an effective method to produce non-dendritic microstructures and reduce casting defects in magnesium alloys. However, the influence of precursor alloy superheat on the solidification behavior and the resulting microstructure remains insufficiently understood. In this study, pure magnesium was used as the high thermal mass (HTM) alloy and three Mg-Al-Zn alloys with different aluminum and zinc contents were used as the low thermal mass (LTM) alloys. The effects of superheat on grain morphology, solute diffusion, and constitutional supercooling were investigated through a combination of experimental casting and numerical simulation using Ansys Fluent and Matlab. The results show that the solidified interface consists of five distinct regions, including two base metals, two transition zones, and a central controlled diffusion solidification zone. A higher superheat of the HTM alloy relative to the LTM alloy promotes a wider transition zone and finer globular grains, whereas equal or lower superheat leads to columnar or rosette structures. The Mg-30 wt.%Al-3.5 wt.%Zn alloy with moderate aluminum content produces fine globular grains due to a thinner constitutional supercooling layer and a higher degree of supercooling, which suppresses grain growth and increases nucleation rate. In contrast, the Mg-55 wt.%Al-6.5 wt.%Zn alloy with high aluminum content forms coarse rosette and columnar grains. Among the conditions investigated, the combination of 10 °C HTM and 5 °C LTM superheats tends to promote the formation of fine equiaxed grains. Increasing superheat above this range reduces supercooling and coarsens grains, while decreasing superheat inhibits interface diffusion and promotes solute segregation. The findings provide a theoretical basis for designing precursor alloy compositions and superheat parameters in controlled diffusion solidification of magnesium alloys. Full article