Search Results (525)

Iron-exchanged bentonites derived from a natural montmorillonite-rich clay (Taganskoe deposit, Kazakhstan) were prepared through a simple aqueous ion-exchange route using Fe(II) or Fe(III) inorganic salt precursors, yielding final Fe contents of ca. 5–7 wt.%, while preserving the smectite layered framework. A mild thermal treatment under air was applied to tune iron coordination without triggering major structural collapse. The resulting materials were characterized by ED-XRF, PXRD, FE-SEM/EDX, DLS/ζ-potential and DR UV–Vis–NIR spectroscopy, revealing predominantly exchanged Fe species with a limited fraction of surface iron-oxide clusters, whose contribution increases after activation. Structure–reactivity relationships were probed under mild conditions in liquid-phase ethyl acetate using dimethyl methylphosphonate (DMMP) and 2-chloroethyl ethyl sulfide (2-CEES) as organophosphorus and organosulfur hazardous chemicals and chemical warfare agent simulants, respectively. Fe(III)-bentonite enabled very fast DMMP removal (ca. 93% within 0.5 h) with a remarkable improved performance with respect to Fe(II)-bentonite and the pristine mineral clay. For 2-CEES, the presence of H₂O₂ markedly enhanced oxidation on Fe-containing clays, reaching quantitative abatement within 24 h (up to >90%), with strong retention of oxidized sulfur products by the clay matrix. These results highlight Fe-exchanged natural bentonites as robust, cheap and multifunctional adsorption/catalytic solids for decontamination and water-treatment applications. Full article

Triple-negative breast cancer (TNBC) is a clinically aggressive malignancy with extremely limited effective targeted therapies. Natural products are promising alternatives for anticancer drug discovery, whereas integrated computational approaches serve as efficient tools for novel lead identification. Herein, four novel spiro-polycyclic sesquiterpene [4+2] trimers (Inubritantrimers A–D) and eight synthetic derivatives from Inula britannica L. were investigated via DFT calculations at the ωB97xD/6-311++G(2d,p) level (for geometric, electronic, spectral, and reactivity parameters), network pharmacology, molecular docking against seven core breast cancer-related targets, 500 ns all-atom molecular dynamics (MD) simulation, and MM/PBSA analysis. The results showed that the endo-type cycloaddition products had superior structural stability, with all reactions thermodynamically spontaneous (ΔG < 0). Compound 11 exhibited the most potent and balanced binding activity, with a docking free energy of −13.45 kcal/mol to MTOR; MD and MM/PBSA confirmed stable complex formation (total binding free energy −21.13 kcal/mol), driven predominantly by hydrophobic interactions. This study first established a comprehensive stereochemistry–electronic structure–property–activity relationship for this rare sesquiterpene trimer class and identified compound 11 as a promising MTOR-targeted TNBC lead. It provided a theoretical basis for developing high-efficiency, low-toxicity natural anticancer agents. Full article

The corrosion of carbon steel in marine–industrial atmospheric environments remains a significant challenge due to the combined effect of aggressive ions such as chlorides and sulfates. In this context, this study aims to explore the inhibitory action of expired omeprazole applied to mild steel AISI 1018 evaluated on a solution simulating atmospheric corrosion (0.1 M Na₂SO₄ + 3% wt NaCl) over 72 h. The material was characterized using EDS to determine its composition of AISI 1018 steel, while Raman spectroscopy was employed to identify the functional groups and heteroatoms present on the molecular structure of omeprazole. Electrochemical noise (EN) measurements were used to evaluate the corrosion rate, type of corrosion and mechanism. Also, quantum chemical calculations of density function theory (DFT) were performed to predict the relationship between molecular structure and inhibition efficiency. The results indicate that 50 ppm provides the most stable and effective corrosion inhibition over time, as evidenced by increases in noise resistance and inhibition efficiency. In contrast, 75 ppm exhibits improved surface morphology at the end of the exposure period, which indicates enhanced surface coverage. The DFT results reveal that omeprazole possesses suitable electronic properties for corrosion inhibition, including moderate reactivity, electron-donating ability, and favorable charge distribution that promotes adsorption onto the metal surface. SEM analysis corroborates that surface damage is significantly reduced in the presence of the inhibitor, particularly at 75 ppm. This study provides new insights into the use of expired pharmaceutical compounds as corrosion inhibitors and demonstrates the capability of combining electrochemical noise analysis with DFT to evaluate both inhibition efficiency and film stability. Full article

Reinjection represents a fundamental strategy for sustainable geothermal reservoir development. During reinjection, reservoirs are subjected to pronounced physicochemical disequilibrium, under which complex water–rock interactions render long–term behavior difficult to predict. This review synthesizes mineral reactions and reservoir dynamic responses from a geochemical perspective. The interplay between reaction kinetics and fluid transport is examined using the Damköhler number, elucidating the spatiotemporal evolution of reactive transport. The dissolution–precipitation behaviors of silicate, carbonate, and sulfate minerals are evaluated, highlighting their distinct roles in governing long–term structural reorganization, short–term permeability variability, and rapid clogging. The influence of mineral reactions on pore structure evolution and the development of nonlinear porosity–permeability relationships is examined, alongside commonly used constitutive models and their inherent limitations. Multiscale characterization approaches for porosity–permeability evolution and the distinct responses of different reservoir types are reviewed. The chemo–mechanical coupling induced by water–rock interactions and its implications for reservoir stability are addressed. This work establishes a unified conceptual framework linking mineral reactions, fluid transport, and reservoir evolution, providing a basis for optimizing reinjection strategies and improving long–term geothermal system performance. Full article

Chinese Traditional Concrete (CTC), known as “San-he-tu,” has ensured the long-term durability of ancient coastal structures, yet its underlying material design logic remains insufficiently understood. This study investigates the Chongwu Ancient City Wall (Quanzhou, China), a Ming Dynasty granite fortification exposed to over 600 years of marine weathering, to elucidate the structure–property–function relationships of CTC across three functional layers: the horse-track surface, wall core backfill, and masonry bonding layer. A multi-technique analytical framework (XRF, XRD, TG, and SEM) was employed to characterize chemical composition, mineral phases, thermal behavior, and microstructure. Results reveal a deliberate “functional adaptability” material design. The surface layer adopts a rigid protective formulation with high quartz (76.9%) and CaO (17.06%), forming a dense, low-porosity matrix resistant to abrasion and weathering. The wall core exhibits a flexible filling strategy with high porosity (35.44%), enabling moisture dissipation and deformation accommodation. The bonding layer, enriched in kaolinite (~29.8%) and reactive Al–Fe components, promotes pozzolanic reactions that generate hydraulic gels, ensuring durable interfacial adhesion under humid coastal conditions. These findings demonstrate that ancient builders engineered zone-specific material compositions to meet distinct structural and environmental demands, forming a functionally graded system analogous to modern material design concepts. This study provides a scientific basis for adopting partitioned, differentiated restoration strategies in coastal heritage conservation. Full article

Hydrogel scaffolds have emerged as a central platform in tissue engineering due to their ability to mimic the extracellular matrix and support cellular functions. Among natural polymers, chitin and its derivative chitosan have emerged as valuable candidates for hydrogel scaffold development because of their biodegradability, compatibility with living tissues, and inherent biological functionality; however, their distinct and complementary roles in hydrogel scaffold design are often insufficiently differentiated in the literature. This review provides a comprehensive and mechanism-driven analysis of chitin- and chitosan-based hydrogel scaffolds, emphasising how their molecular structure governs network formation, mechanical performance, and biological functionality. Chitin is highlighted primarily as a structurally robust and crystalline component suitable for reinforcement. In contrast, chitosan serves as a versatile, soluble, and chemically reactive matrix enabling various crosslinking and functionalization strategies. Recent advances in physical, ionic, and covalent crosslinking as well as composite scaffold engineering, biofunctionalization, and emerging fabrication approaches such as injectable systems and three-dimensional bioprinting are systematically examined. The relationships between scaffold architecture, degradation behaviour, and cellular responses are discussed in key tissue engineering applications, including bone, cartilage, skin, and nerve regeneration. Importantly, this review introduces a unified structure–property–function framework that distinguishes the roles of chitin and chitosan within hydrogel systems and links crosslinking mechanisms to application-specific performance requirements, an aspect not comprehensively addressed in previous studies. Current challenges related to mechanical limitations, material variability, and clinical translation are critically evaluated, and future perspectives for the rational design of next-generation biomimetic hydrogel scaffolds are proposed. Full article

Oxygen vacancies play a crucial role in modulating the chemical and catalytic properties of metal oxide catalysts. Herein, quercetin was used as a green reducing agent to prepare Cu-doped MnO₂ (Cu-MnO₂) composite catalysts with varying Cu doping levels via an ultrasonically assisted strategy. The structure-activity relationships were systematically investigated using XRD, Raman, XPS, H₂-TPR, and O₂-TPD. Benefiting from optimized surface lattice defects induced by an appropriate Cu doping level, the Cu-MnO₂-2 sample, which exhibited the highest oxygen vacancy concentration, achieved a HCHO removal efficiency of 99.2% for 1 ppm HCHO at room temperature (25 °C) and 50% relative humidity within 30 min. The enrichment of Mn³⁺, Cu⁺, and surface-adsorbed oxygen species (O_ads) further corroborated the increased oxygen vacancy density, indicating that moderate Cu doping effectively promotes electron transfer and oxygen activation. After five consecutive cycles, the HCHO conversion remained above 96%. Post-cycling characterizations (XRD, FTIR, EDS, and XPS) confirmed the excellent structural and chemical stability of the catalyst, with the Mn³⁺ proportion and Cu⁺/Cu²⁺ ratio well preserved. In situ DRIFTS analysis revealed that surface-adsorbed oxygen and oxygen-vacancy-activated reactive oxygen species (ROS) are key factors in the efficient HCHO oxidation over the green Cu-MnO₂-2 catalyst, promoting rapid conversion of intermediates and ultimately generating CO₂ and H₂O. This study provides a facile, low-cost, and green synthesis strategy for Cu-MnO₂ composite catalysts for indoor, room-temperature HCHO abatement, offering new insights into the design of other composite catalyst materials. Full article

The increasing digitalization of manufacturing systems and emphasis on sustainable development are transforming maintenance from a purely operational function into a strategic driver of customer value in the digital economy. However, the relationship between maintenance maturity and consumer-perceived sustainability remains largely unexplored. This study addresses the following research questions: (RQ1) How does maintenance maturity influence consumer-perceived sustainability and trust? (RQ2) How can operational resilience be linked to customer perception through a structured modeling approach? (RQ3) Which maintenance strategy provides the highest combined operational and sustainability value? To address these questions, the Integrated Maintenance Maturity Model with a Customer-Centric Sustainability Layer (IMMM–CCSL) is proposed. The framework links maintenance maturity with consumer sustainability perception using a structured fuzzy-based aggregation approach. Five consumer-oriented dimensions are considered: product lifecycle extension, service continuity and trust, consumer maintenance experience, perceived ecological performance, and post-sale engagement. A composite Customer Sustainability Index (CCSI) is introduced to quantify the relationship between maintenance maturity and consumer perception. The model is applied in an illustrative case study comparing reactive, preventive, predictive, and AI-enhanced maintenance strategies. The results indicate that CCSL values range from 0.709 to 0.749, while the overall CCSI equals 0.729, suggesting a consistently high level of consumer-perceived sustainability associated with higher maintenance maturity. Predictive maintenance demonstrates the highest contribution to both operational reliability and perceived sustainability outcomes within the analyzed case. Overall, the IMMM–CCSL framework offers a structured, interpretable tool for aligning maintenance strategy with sustainable production and consumption objectives, supporting managers and policymakers in translating technical capabilities into measurable consumer sustainability outcomes. The findings should be interpreted as exploratory and case-specific, given the illustrative nature of the study. Full article

Chromium-containing ferroalloy wastes represent an important secondary resource; however, chromium is mainly bound in thermodynamically stable spinel phases, which complicates its reduction. Unlike previous studies focusing on pure oxide systems, this work demonstrates the enhanced destabilization and subsequent reduction of MgCr₂O₄ spinel in real ferroalloy wastes under SHS conditions, revealing a non-monotonic relationship between activation time and reduction efficiency. A critical activation threshold (~30 min) was identified, beyond which particle agglomeration suppresses reaction kinetics. Powder mixtures based on HShP and KEK wastes with Al–C–Si reducing agents were mechanically activated for 10–120 min and subsequently subjected to SHS at 950 °C. The combustion parameters, phase composition (XRD), microstructure (SEM), and elemental composition (EDS) were analyzed. The results show a pronounced non-monotonic dependence of combustion temperature and front velocity on activation time, with maximum values at ~30 min (1920 °C and 1.10 mm/s for HShP; 1765 °C and 0.98 mm/s for KEK). XRD analysis indicates that MgCr₂O₄ was not detected within the XRD detection limits and that the highest relative amount of metallic chromium phase (~8% for HShP and ~6.8% for KEK) was observed at the same activation time. SEM observations reveal the formation of a more dispersed and porous structure, while EDS indicates an increase in chromium content up to ~15 wt.% in local regions. At longer activation times, overgrinding and agglomeration reduce process efficiency. Mechanical activation enhances chromium reduction through improved mass transfer, with an optimal activation time of ~30 min. The chromium reduction efficiency was evaluated using a semi-quantitative approach based on XRD phase analysis and supported by EDS data, allowing comparative assessment of reduction efficiency rather than absolute extraction values. These results highlight the existence of a critical mechanochemical activation threshold governing the balance between enhanced reactivity and agglomeration effects. Full article

Background: Posttraumatic stress disorder (PTSD) in ages 3–18 is associated with disturbances in attention, working memory, processing speed, and executive control, as well as persistent difficulties in affect regulation. These neuropsychological vulnerabilities might interfere with learning, peer relationships, and the consolidation of age-appropriate developmental skills. Methods: We conducted a narrative review informed by a structured literature search in PubMed, Scopus, PsycINFO, Embase, EBSCOhost, Web of Science, and Google Scholar. English-language publications from 1990 to 2025 were considered if they examined (1) neuropsychological outcomes of trauma exposure or PTSD in youth and/or (2) interventions with potential to modify neurocognitive or affective functioning, including trauma-focused cognitive behavioral therapy (TF-CBT), mindfulness-based interventions, cognitive rehabilitation strategies, and biofeedback/neurofeedback. Results: Across study designs, trauma exposure and PTSD in youth are consistently linked to impairments in attentional control and executive functioning, with downstream effects on everyday memory and academic performance. Neurobiological studies commonly implicate altered reactivity within amygdala-centered threat circuits and reduced top-down modulation by prefrontal networks, although findings vary with trauma type, developmental stage, and comorbidity. TF-CBT remains the best-supported intervention for pediatric PTSD symptoms; however, neurocognitive outcomes are measured less frequently. Mindfulness-based programs show promise for strengthening attention and emotion regulation when carefully adapted for trauma-exposed youth. Neurofeedback and targeted cognitive rehabilitation represent emerging approaches with preliminary evidence, but the literature remains heterogeneous. Conclusions: An intervention strategy that combines symptom-focused trauma therapy with explicit targeting of executive control, memory processes, and affect regulation may represent a developmentally informed clinical framework for trauma-exposed youth. Future trials need to incorporate standardized neuropsychological endpoints and examine moderators that inform treatment matching. Full article

High-entropy alloys (HEAs) have emerged as an important class of materials for solid-state hydrogen storage because their compositional complexity provides access to diverse phase constitutions, local lattice environments, and hydrogen-related responses. However, hydrogen-storage behavior in these alloys cannot be understood from composition alone. What ultimately governs performance is the microstructural state generated during preparation. This perspective examines HEAs from that standpoint, focusing on how different preparation routes produce distinct structural states and how those states determine hydrogen accommodation, diffusion, phase transformation, and reversibility. Arc melting and subsequent homogenization typically generate bulk refractory alloys with comparatively simple average phase constitution, whereas mechanical alloying and reactive ball milling produce defect-rich, fine-scale, and metastable non-equilibrium structures. Representative systems are discussed to show that even alloys with similar nominal compositions may follow different hydriding pathways once their structurally realized state changes. The article further evaluates the structural descriptors most often invoked in the field, including phase constitution, local lattice environment, grain size, defect density, interface density, chemical homogeneity, and processing history. It is argued that future progress will depend less on continued composition screening alone than on establishing more transferable microstructure–hydrogen-storage relationships across route-defined structural states. Full article

Epoxy resins are widely used thermosetting polymers, but their limited toughness and flexural resilience restrict broader applications. In this study, diglycidyl ether of bisphenol A (DGEBA) epoxy was reinforced with 5 wt.% ceramic fillers of different origins: sol–gel alumina calcined at 550 °C (γ-Al₂O₃) and 1000 °C (α-Al₂O₃), silica derived from rice husk, silica from diatomaceous earth, and a hybrid alumina–silica mixture prepared by sol–gel and calcined at 1000 °C. Fillers were structurally characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field-emission scanning electron microscopy (FESEM). Mechanical properties were evaluated through tensile (ASTM D638) and flexural (ASTM D790) testing. All reinforcements enhanced the performance of neat epoxy. γ-Al₂O₃ provided superior tensile reinforcement compared to α-Al₂O₃, underscoring the importance of particle morphology and surface reactivity. The hybrid alumina–silica filler achieved the highest flexural strength of 50.6 MPa, compared to 9.91 MPa for the neat epoxy. Bio-derived silica showed improved flexural properties, although its tensile reinforcement was less pronounced compared to the sol–gel derived fillers. These results establish clear structure–property relationships and confirm that filler phase, morphology, and calcination temperature critically govern the mechanical performance of epoxy composites. Full article

The cathodic oxygen reduction reaction (ORR) remains a major kinetic barrier to high-efficiency proton exchange membrane fuel cells (PEMFCs), motivating the search for electrocatalysts that combine high activity, low metal usage, and long-term durability. This review examines single-atom catalysts (SACs) as an emerging platform for fuel-cell cathodes with particular emphasis on how atomic-level design, ORR mechanism, and practical deployment barriers are interrelated. The review discusses the key ORR pathways, intermediate binding principles, and scaling constraints that govern cathodic performance, and examines how metal-center selection, coordination-environment engineering, support regulation, synergistic multi-site construction, and morphology-controlled synthesis can be used to tune intrinsic activity and stabilize isolated active sites. It further highlights mechanistic insights from theoretical and operando studies, with emphasis on structure–activity relationships, dynamic active-site evolution, and approaches to mitigate scaling limitations. Major barriers to practical deployment, including carbon corrosion, demetalization, agglomeration, peroxide/reactive oxygen species attack, and the persistent gap between half-cell metrics and membrane electrode assembly performance, are also critically assessed. Rather than treating these topics separately, this review discusses them as connected factors that together determine the viability of SAC-based fuel-cell cathodes. Full article

Background: Psoriasis is a chronic immune-mediated inflammatory disorder strongly associated with cardiometabolic comorbidities. Although methotrexate (MTX) is widely used for moderate-to-severe disease, its influence on the relationships between inflammatory and metabolic biomarkers remains insufficiently characterized. Methods: This retrospective observational study included 132 hospitalized adult patients with psoriasis, stratified into untreated (n = 101) and MTX-treated (n = 31) groups. Inflammatory markers, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), neutrophil-to-lymphocyte ratio (NLR), and systemic immune-inflammation index (SII), and metabolic indices, triglyceride–glucose index (TyG), metabolic score for insulin resistance (METS-IR), and atherogenic index of plasma (AIP), were analyzed. Group comparisons were performed using Mann–Whitney U and χ² tests. Spearman correlation matrices and regularized partial correlation networks (EBICglasso, γ = 0.5) were constructed separately for each group to explore inflammatory–metabolic connectivity. Results: MTX-treated patients exhibited lower NLR (p = 0.035) and fasting glucose levels (p = 0.004), while CRP, ESR, and composite metabolic indices did not differ significantly. In untreated patients, correlation analysis showed multiple significant cross-domain associations between inflammatory and metabolic markers. In contrast, fewer such associations reached statistical significance in the MTX-treated group. Network analysis indicated a less densely connected structure in the MTX group (9 vs. 12 non-zero edges); however, formal network comparison did not identify statistically significant differences between groups. Conclusions: Although fewer statistically significant cross-domain correlations were observed in MTX-treated patients, no statistically significant differences in network structure were detected between groups. These findings are exploratory and hypothesis-generating, not indicative of methotrexate-related modification of network structure, and are limited by the small size of the MTX-treated subgroup. Full article

Urushiol, the key component of natural lacquer, is emerging as a versatile bio-based phenolic platform for advanced polymer systems. Its unique catechol structure, combined with an unsaturated aliphatic side chain, provides multiple reactive sites, enabling diverse chemical pathways and tunable network architectures. This review presents a systematic analysis of urushiol-based materials within a “structure–reaction–property–application” framework. The intrinsic reactivity of urushiol, including oxidative polymerization, dynamic covalent bonding, and metal–phenolic coordination, is correlated with the formation of crosslinked networks exhibiting controllable mechanical properties, strong interfacial adhesion, and stimuli responsiveness. Recent advances in functional coatings, self-healing and reversible polymers, bioactive materials, and cultural heritage conservation are highlighted. Special emphasis is placed on dynamic network design and low-sensitization strategies to overcome limitations of traditional lacquer systems. Finally, key challenges and future directions toward controllable curing, structure–property relationships, and sustainable material design are discussed, positioning urushiol as a bridge between traditional materials and next-generation functional polymers. Full article