Search Results (31,679)

In line with circular economy principles, raw spent yerba mate (Ilex paraguariensis) waste (YMs) was transformed into a high-value aminated adsorbent (AYMs) for the removal of anionic dyes, namely Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84). The modification involved a two-step process using epichlorohydrin and aqueous ammonia, and the adsorbents were characterized via FTIR, BET, C/N elemental analysis, and pH_PZC. Batch experiments evaluated pH effects, kinetics (PFO, PSO, and intraparticle diffusion), and equilibrium isotherm analysis (single- and dual-site Langmuir models and Freundlich models). The results confirmed successful functionalization of the biomass with amino groups, shifting the point of zero charge (pH_PZC) from 4.74 (YMs) to 8.73 (AYMs). The optimal adsorption pH was 2.0 for YMs and 3.0 for AYMs. Kinetic data were best described by the pseudo-second-order model, while equilibrium data followed the dual-site Langmuir model, indicating energetic heterogeneity of the AYMs surface. The maximum adsorption capacity of AYMs reached 62.81 mg·g⁻¹ for RB5 and 61.78 mg·g⁻¹ for RY84, representing a fivefold and threefold increase over the YMs, respectively. These findings demonstrate that AYMs is a high-performance, sustainable alternative to commercial activated carbons, providing a scalable waste-to-value solution for industrial effluent treatment. Full article

Pancreatic lipase (PL) inhibition is a promising dietary strategy for obesity management. In this study, the inhibitory mechanisms and structural basis of polyphenols extracted from different sugarcane fractions were investigated using in vitro enzyme assays, spectroscopy, and molecular docking analyses. PL inhibitory activity was evaluated using p-nitrophenyl laurate (pNPL) as the substrate, with all assays performed in triplicate and results statistically analyzed. Among the extracts, sugarcane peel polyphenols (SP) exhibited the strongest inhibition, with a half-maximal inhibitory concentration (IC₅₀) of 31.56 mg/mL, significantly lower than that of sugarcane juice polyphenols (SJ, 55.86 mg/mL) and sugarcane bagasse polyphenols (SB, 65.31 mg/mL). Enzyme kinetic analyses revealed a reversible mixed-type inhibition mechanism. In contrast to crude extracts, individual phenolic monomers showed substantially lower IC₅₀ values (0.13–1.33 mg/mL), highlighting the intrinsic dilution. Compositional analysis identified ferulic acid, gallic acid, chlorogenic acid, and schaftoside as key contributors to PL inhibition. Fourier transform infrared (FTIR) and fluorescence spectroscopy demonstrated that polyphenols altered PL secondary structure by modulating α-helix and β-sheet contents and perturbed the microenvironment of tryptophan (Trp) and tyrosine (Tyr) residues. Molecular docking further indicated that these compounds bind within or near the substrate-binding channel via hydrogen bonding and hydrophobic interactions, engaging critical residues including Ser152, His263, and Phe77, and potentially influencing conformational elements involved in active-site accessibility. Collectively, these results suggest that sugarcane, particularly its peel, represents a valuable natural source of PL inhibitors. Despite the relatively high IC₅₀ values of crude extracts, their inhibitory activity arises from multicomponent contributions and supports their potential application as dietary modulators of fat digestion rather than as pharmaceutical lipase inhibitors. Full article

The residual sub-millimeter metal particles in gas-insulated metal enclosed switchgear (GIS) and gas-insulated transmission lines (GILs) are significant factors that trigger insulation failures. During actual operation, these particles not only endure the action of alternating electric fields but also are continuously stimulated by mechanical vibrations. Current research mostly focuses on the behavior of millimeter-sized particles under a single physical field, lacking in-depth understanding of the jumping characteristics of sub-millimeter-scale particles under the combined action of alternating electric fields and mechanical vibrations. This paper has built a collaborative action test platform and constructed a spherical-bowl-shaped electrode defect model. It systematically studied the jumping behavior, motion evolution, and local discharge characteristics of 20-mesh and 40-mesh irregular aluminum particles under the combined action of different voltages (0–7 kV) and mechanical vibrations (amplitude 0.01–0.1 mm, frequency 10–100 Hz). The results show that mechanical vibrations provide initial kinetic energy for the particles, significantly reducing the threshold for jumping, and are the key initiating factor in the collaborative action; in the low-voltage stage, vibration dominates the jumping behavior, while in the high-voltage stage, the electric field dominates the motion evolution; and under dual stimulation, the jumping area of the particles is wider and the motion forms are more diverse (such as flying-flying motion, vertical state, pile-up excitation, etc.), and the starting voltage of discharge is significantly reduced, the discharge repetition rate increases with the increase in vibration intensity and voltage, and is closely related to the particle size. This paper reveals the uniqueness of particle motion and discharge under the collaborative action, providing a theoretical basis for the assessment of multi-physical field states and fault prediction of GIS/GIL. Full article

With natural gas demand growing rapidly in this century, solidified natural gas technology holds great potential for strengthening energy resilience and delivering secure global gas supply. However, this technology is still impeded by insufficient gas uptake capacity and sluggish hydrate formation rate. Environmentally benign peptides have recently emerged as a novel class of green hydrate promoters. Different from single amino acids, peptides exhibit significant structural diversity owing to their varying sequences and combinations of their constituent amino acid monomers, showing great potential in hydrate-based applications. In this work, a unique tripeptide promoter, L-glutathione reduced (GSH), was employed, and the thermodynamic influence factors in methane hydrate formation were systematically investigated. Furthermore, as a highly hydrophilic amino acid, L-arginine was chosen for a comparative kinetic investigation with extremely hydrophilic GSH. The results revealed that experimental pressure showed a strong effect on the methane uptake rate, while it presented little influence on final methane storage capacity. The initial temperature greatly affected the average induction time, the rate of hydrate growth, and the yields of hydrates promoted by GSH. Increasing temperature resulted in a significant reduction in both the hydrate formation rate and methane uptake at 3 h. Therefore, in the GSH-promoted hydrate formation process, suitable pressure and temperature should be carefully chosen for desirable hydrate performance. Furthermore, the initial 15 min hydrate formation rate of 0.3 wt% L-arginine is 52.4% lower than that of 0.3 wt% GSH. The final methane uptake of 0.3 wt% arginine is substantially smaller than that of 0.3 wt% GSH. Although both GSH and arginine exhibit strong hydrophilic properties, the tripeptide GSH is more effective than the amino acid arginine in enhancing methane hydrate formation. The insights gained from this work offer a theoretical foundation for the application of peptide-based promoters in solidified natural gas technology. Full article

We propose a dimensionally consistent fractional spatio-temporal PDE framework for modelling immune-mediated demyelination in multiple sclerosis (MS). The system couples effector and regulatory T cells, M1/M2 macrophage polarisation, pro- and anti-inflammatory cytokines, oligodendrocyte dynamics, and time-dependent therapeutic controls within a unified distributed-parameter structure. In contrast to ad hoc replacements of integerorder derivatives by Caputo fractional derivatives, the fractional extension proposed here is derived from an underlying continuous-time random walk (CTRW) process with Mittag–Leffler-distributed residence times. This stochastic derivation yields a governing system in which a single commensurate fractional order α ∈ (0, 1], together with a characteristic memory timescale τ0, ensures dimensional consistency and mass balance across all coupled components. The model is formulated as a system of nonlinear reaction–diffusion equations with cross-regulatory and multiplicative interaction terms governing immune amplification, cytokine feedback, and the demyelination–remyelination balance. Analytical interpretation shows how non-Markovian residence times induce Mittag–Leffler-type relaxation and thereby modify effective growth, decay, and stability properties. Numerical simulations compare classical and fractional dynamics, revealing that memory-driven kinetics prolong effector T-cell and M1-macrophage activity, attenuate reparative M2 and oligodendrocyte responses, and extend the effective action of bang–bang therapy inputs representing IFN-β and glatiramer acetate beyond their dosing windows. The results indicate that integer-order models may underestimate chronic inflammatory persistence and demyelination severity, while providing a mathematically and physically well-posed platform for memory-aware immune modelling and therapy evaluation in MS. Full article

Iso-cetane serves as an ideal component representing branched-chain alkanes in surrogate fuels for diesel. However, the predictive accuracy of existing detailed chemical kinetic models for iso-cetane requires improvement. In this study, focusing on the reaction processes of iso-cetane and its key intermediates, we first updated the thermodynamic data of iso-cetane and some of its intermediates, systematically analyzed the effects of various reactions on ignition delay time (IDT), and made targeted modifications to the relevant reaction rate constants. The reaction types involved include fuel cracking reactions of iso-cetane, hydrogen abstraction reactions, cracking reactions of fuel radicals, as well as the oxidation of fuel radicals, isomerization of alkylperoxy radicals (RO₂ )  concerted elimination reactions, formation of cyclic ethers, and the formation and decomposition of ketohydroperoxides (KHP). Additionally, reactions related to the formation and consumption of p-alkyl-dihydroperoxides (P(OOOH)₂) were supplemented. Based on the above work, we developed a detailed chemical kinetic model for iso-cetane, comprising 4541 species and 18,359 elementary reactions. Through systematic validation against experimental data on ignition delay time and concentration variations of key species during oxidation, the improved predictive performance of the proposed model was demonstrated. Furthermore, using sensitivity analysis and reaction pathway analysis for the ignition process, we revealed that the formation of the low-temperature negative temperature coefficient (NTC) region for iso-cetane is intrinsically associated with the competition between chain-branching and chain-propagating pathways. Full article

Background/Objectives: Synthetic stimulants represent the most prevalent subclass on the new psychoactive substances (NPSs) market. However, the toxicokinetic properties of M-ALPHA, a regioisomer of MDMA and N-methyl-cyclazodone a pemoline derivative, are not yet characterized. Methods: Therefore, this study investigated the metabolism of both NPSs in pooled liver S9 fraction and rat urine, characterized cytochrome P450 (CYP) kinetics and plasma protein binding (PPB), and assessed the CYP inhibition potential of M-ALPHA, using high-performance liquid chromatography coupled to high resolution tandem mass spectrometry (HPLC-HRMS/MS). Results: Four metabolites of M-ALPHA were detected including one phase I and three phase II metabolites, resulting from demethylenation followed by subsequent methylation or glucuronidation. For N-methyl-cyclazodone, one phase I metabolite formed via N-demethylation was identified. The primary enzymes involved in M-ALPHA metabolism were CYP2B6 and CYP2D6. Notably, M-ALPHA inhibited these enzymes to a strong or moderate extent, respectively. In contrast, the metabolism of N-methyl-cyclazodone was primarily mediated by CYP2A6. PPB studies indicated low-to-moderate binding for both compounds, suggesting that significant protein-binding interactions are unlikely. Conclusions: As M-ALPHA only formed metabolites that overlapped with those of MDMA, differing only by minor retention time shifts, reliable HPLC-HRMS/MS-based identification may be challenging in clinical and forensic toxicology settings as well as doping analysis. Furthermore, drug–drug interactions following polydrug use cannot be excluded for either NPS, particularly when co-ingested with other CYP substrates metabolized by the same isoforms. Full article

The CO₂ storage–regeneration (CO₂-SR) process represents a promising strategy for integrating CO₂ capture and catalytic conversion within a single cyclic operation using multifunctional catalysts. In this concept, CO₂ is first stored on basic sites and subsequently converted through methane activation, enabling the coupling of CO₂ capture and reforming reactions in a single reactor. In this work, a series of unsupported Ni–Ba catalysts were investigated as model multifunctional materials for the CO₂-SR process. Catalysts with different Ni/Ba ratios were prepared to analyze how the distribution of storage and catalytic sites influences the cyclic CO₂ capture–conversion behavior. In addition, Rh was introduced as a promoter either during synthesis by co-precipitation or ex situ by impregnation, allowing to evaluate the influence of Rh location and surface enrichment on the catalytic properties. Rh incorporation in the NiBa catalyst (Ni/Ba = 10/1 and Ni/Rh = 100/1) increased the specific surface area (BET area 64 m²·g⁻¹ vs. 55 m²·g⁻¹ for NiBa) and reduced the NiO crystallite size from 250.4 Å to 231.5 Å, indicating improved dispersion of the metallic phase. XPS analysis revealed the coexistence of Rh⁰ and Rh³⁺ species, suggesting that Rh acts as a redox mediator that facilitates hydrogen activation and promotes hydrogen spillover to neighboring Ni sites. Raman and CO₂-TPD results show that Ba-derived domains stabilize carbonate species responsible for CO₂ storage, while Rh enhances catalyst reducibility and modifies the kinetics of carbonate decomposition during the regeneration stage. Transient CO₂–CH₄ pulse experiments demonstrate that the CO₂-SR process proceeds through a dynamic surface cycle involving reversible carbonate formation on Ba-derived basic sites coupled with methane activation on Ni-containing interfacial sites. The results indicate that catalyst performance is governed by a hierarchical surface architecture composed of Ni–O–Ba interfacial domains, reversible Ba–O–Ba carbonate storage sites, and more stable Ba-rich domains. The distribution of these domains, controlled by the Ni/Ba ratio and the dispersion of the metallic phase, determines the reversibility of carbonate formation and the efficiency of the cyclic CO₂ storage–regeneration process. Full article

Background: Recurrence poses a major challenge in epithelial ovarian cancer (EOC), often occurring despite optimal first-line therapy. Dormant cancer cells are believed to play a key role, yet the mechanisms driving their reactivation remain unclear. This study examined whether exosomes released by normal peritoneal mesothelial cells (PMCs) and fibroblasts (PFBs) undergoing iatrogenic senescence after carboplatin and paclitaxel exposure contribute to EOC recurrence. Methods and Results: Senescent PMCs and PFBs secreted markedly more exosomes, identified by CD9, CD63, and CD81, compared with young cells. Exosomes from both cell types more effectively reactivated dormant EOC cells (pEOCs, A2780, OVCAR-3, SKOV-3) than non-exosomal medium constituents. Importantly, senescent PMC-derived exosomes most strongly reactivated pEOCs and SKOV-3, whereas those from senescent PFBs exerted greater effects on pEOCs, OVCAR-3, and SKOV-3. Kinetic studies of exosome internalization revealed that this process was generally more efficient in the presence of exosomes derived from senescent cells compared with those from young donor cells. Compositional analysis revealed distinct profiles between young and senescent exosomes compared in two variants: young PMCs/senescent PMCs and young PFBs/senescent PFBS. Senescent PMC exosomes displayed reduced miR-210-3p, miR-409-3p, and miR-421, alongside elevated MMP1, MMP3, and VEGF, while senescent PFB exosomes showed increased amphiregulin and osteopontin but lower MMP1, MMP3, TIMP1, bFGF, VEGF, and HGF. Functionally, senescent PMC exosomes enhanced pEOC migration, invasion, and spheroid formation, and induced the expression of CCL11 and ABCB1. Senescent PFB exosomes promoted migration and upregulated CCL11, TGF-β1, BIRC5, and CHEK1. Conclusions: These findings suggest that therapy-induced senescence in peritoneal cells may contribute to EOC recurrence by reactivating dormant tumor cells through exosomal signaling. Full article

The Zircaloy-4 alloy is a key structural material for nuclear reactor cores. However, its behavior under warm deformation conditions and during phase transformations requires in-depth investigation to improve technologies for producing ultrafine-grained (UFG) structures using severe plastic deformation methods. This work presents a comprehensive study of the rheological properties, phase stability, and microstructural evolution of the alloy in the temperature range from 20 to 950 °C at strain rates of 0.5 and 15 s⁻¹. The experimental part included plastometric testing, dilatometric analysis, and microstructural characterization. It was established that the optimal window for plastic deformation corresponds to warm deformation at 650 °C. Dilatometric analysis confirmed that heating to 650 °C ensures the preservation of a stable initial α-phase structure, since the formation of secondary phases and the α→β transformation are initiated at higher temperatures, namely 694 °C (onset) and 847 °C (completion). At 650 °C, the deformation resistance decreases by approximately 70% compared to cold processing, while the strain-rate sensitivity of the flow stress is minimized. EBSD analysis showed that deformation under these conditions leads to intensive grain fragmentation via mechanisms of dynamic recovery and the initial stages of continuous dynamic recrystallization. The decisive role of the kinetic factor was demonstrated: reducing the strain rate to 0.5 s⁻¹ promotes the formation of a finer and more homogeneous grain structure. In contrast, high strain-rate deformation (15 s⁻¹) results in coarser grains and increased non-relaxed intragranular residual stresses. The obtained results provide a physical basis for optimizing thermomechanical processing regimes and can be used to produce UFG structures in zirconium alloys without the risk of phase degradation. Full article

The Activators Regenerated by Electron Transfer Atom Transfer Radical Polymerization (ARGET-ATRP) of vanillin methacrylate (VMA), a bio-based methacrylic monomer derived from vanillin, was systematically studied for the first time. The reaction conditions were optimized aiming at achieving good monomer conversions while preserving the antimicrobial aldehyde functionality. Bipyridine-based catalysts showed limited effectiveness, whereas polydentate aliphatic amines displayed higher activity. Kinetic studies showed linear profiles during the early stages of the polymerization before reaching a conversion plateau accountable to the depletion of the reducing agent, as confirmed by reactivation experiments. The resulting polymer (PVMA) exhibited a glass transition temperature comparable to that of poly(styrene), emerging as a potential bio-derived alternative to fossil-based thermoplastic materials. Furthermore, preliminary in vitro tests demonstrated that PVMA has potential antimicrobial activity against both Escherichia coli (Gram-negative) and Bacillus subtilis (Gram-positive). Full article

Translating preclinical findings into effective clinical cancer immunotherapies remains a major challenge, mainly because conventional in vitro and animal models often fail to capture the complexity, dynamics, and species-specific features of human immune responses. Organ-on-a-chip (OoC) technologies that combine engineered tissue architectures with precisely controlled microfluidic transport provide human-relevant microphysiological platforms for mechanistic studies of immune–tumor interactions and evaluation of therapeutic efficacy and immunotoxicity under defined microenvironmental conditions. However, immune responses involve time-dependent and interconnected processes, including immune cell trafficking, cytokine programs, metabolic shifts, and cytolysis, that are not adequately resolved by static or endpoint assays. Engineering immune-competent OoC systems therefore requires coordinated design of platform architectures, immune cell incorporation strategies, and integrated measurement workflows capable of capturing dynamic and state-dependent responses. In this review, we summarize engineering strategies for building immune-competent OoC platforms for cancer immunotherapy, focusing on platform architectures, immune cell incorporation methods, and fit-for-purpose assay workflows. Emphasis is placed on embedded sensing modalities (e.g., cytokine, oxygen, and impedance readouts) that provide valuable kinetic and state-variable data. Finally, we discuss key translational challenges, including reproducibility, standardization, and benchmarking, and outline near-term priorities to accelerate the adoption of immune-competent OoC systems in immunotherapy research and development. Full article

Background: Nanoporous anodic alumina (NAA) has emerged as a promising platform for localized drug delivery in biomedical implants owing to its tunable nanoscale pore structure and biocompatibility. However, achieving the desired pore characteristics currently relies on time-consuming trial-and-error adjustments of anodization parameters. Methods: We developed a comprehensive data-driven machine learning framework using a feed-forward artificial neural network (ANN) with three hidden layers (64-32-16 neurons) trained on 77 samples from a compiled dataset of 99 anodization experiments spanning 1995–2025. The model predicts the NAA pore diameter based on anodization conditions (electrolyte type, concentration, voltage, temperature, and time). Results: The ANN achieved R² = 0.803, root mean square error (RMSE) = 25.83 nm, and mean absolute error (MAE) = 17.05 nm on training data; however, 5-fold cross-validation revealed moderate generalization (CV R² = 0.471 ± 0.078). Multiple linear regression showed comparable training performance (R² = 0.804) but superior cross-validation (CV R² = 0.729 ± 0.083). Feature importance analysis identified anodization voltage (29.15% ANN importance) and electrolyte type (30.23%) as the most influential factors. Coupling ANN-predicted pore dimensions with Higuchi diffusion modeling demonstrated that the pore diameter increased from 50 to 100 nm, nearly doubling the initial release rates (8 to 11 h⁻¹) and reducing the time to 50% release from 39.1 to 20.7 h. Conclusions: This data-driven approach offers a powerful tool to reduce experimental iteration and accelerate the development of advanced drug-delivery implants by enabling the rational design of NAA pore structures for optimized drug loading and release kinetics. Full article

Hydrogen is a key energy carrier for the transition to renewable energy, but its storage remains a major challenge, mainly due to the energy requirements for its production and to its low volumetric energy density under ambient conditions. Clathrate hydrates have recently emerged as a promising medium for gas storage, yet their potential for hydrogen storage is still underexplored. This study presents a comprehensive bibliometric analysis of hydrogen storage research, focusing on clathrate hydrates. The analysis, based on publications indexed in Scopus over the past decades, reveals that research on gas hydrates is mature and interdisciplinary, encompassing hydrate formation, thermodynamics, and production from natural reservoirs. In contrast, hydrogen hydrates remain a marginal and emerging research area, characterized by limited scientific output and weak connections to dominant storage strategies such as metal hydrides, metal–organic frameworks, and adsorptive materials. The results highlight key research gaps, including a limited understanding of formation kinetics, thermodynamic stability under practical conditions, and challenges related to scalability and system integration. These findings suggest that targeted research efforts addressing these bottlenecks could support the development of hydrate-based systems as complementary solutions within the broader hydrogen storage landscape. Full article

Trans-anethole oxygenase (TAO) exhibits broad arylpropene substrate specificity but has low activity in converting isoeugenol to high-value vanillin. Herein, we employed computer-aided rational design to engineer TAO from Pseudomonas putida (PpTAO) for enhanced catalytic efficiency toward isoeugenol. Structural modeling and AlphaFold 3 docking identified two key catalytic residues, Arg86 and His118. Through substrate channel engineering and computation-guided mutagenesis, a series of targeted variants were constructed. Three variants, H93A, Q207R/G249C, and I59T/F62T, showed significant improvements in whole-cell performance, with activity increases of 1.8-, 2.13-, and 4.83-fold over the wild type (WT), respectively. Purified enzyme kinetics corroborated these findings, as reflected in k_cat/K_m values that reached 1.6, 2.1, and 4.7 times that of the WT. Mechanistic molecular dynamics simulations revealed that H93A enhances activity by widening the access tunnel, whereas Q207R/G249C exerts beneficial distal effects. Notably, the I59T/F62T variant significantly increases substrate affinity by optimizing hydrophobic interactions within the binding pocket. These results validate the efficacy of computational modeling in enzyme redesign and provide a robust biocatalyst for the sustainable biosynthesis of vanillin. Full article