Search Results (7,823)

This review provides a comprehensive and critical analysis of geopolymers, focusing on structure–property relationships and functionalization strategies for sustainable applications. A structured narrative review methodology was adopted, following PRISMA principles, based on literature retrieved from Web of Science, Scopus, ScienceDirect, and MDPI databases, primarily covering the period 2015–2025. The influence of precursor type, alkaline activators, and Si–Al ratio on reaction kinetics, microstructure, porosity, and mechanical performance is systematically discussed. Functionalization approaches using additives are critically reviewed with respect to durability, fire resistance, photocatalytic activity, and antibacterial performance. The analysis highlights that the geopolymer matrix primarily acts as stable and versatile support, while functional performance is governed by the controlled integration of active particles. Key limitations related to the variability of raw materials, lack of standardization, and long-term durability are identified. Future research directions are outlined, emphasizing the need for standardized processing protocols and the application-oriented design of multifunctional geopolymer systems. Full article

Eco-anxiety has emerged as a significant psychological response to the climate crisis. Yet its relationship with pro-environmental behavior remains far from settled, with findings ranging from behavioral paralysis to active engagement and seemingly contradictory evidence accumulating across studies. To clarify both the magnitude of this association and the conditions under which it holds, we conducted a systematic review and three-level random-effects meta-analysis. We systematically searched five databases (ProQuest, APA PsycArticles, PubMed, among others) through April 2025, identifying 20 independent studies that contributed 60 effect sizes (N = 34,206). The pooled results revealed a significant, small-to-moderate positive association between eco-anxiety and pro-environmental behavior (r = 0.24, 95% CI [0.15, 0.32], p < 0.001). So far, fairly straightforward. The complication emerged when examining heterogeneity: we observed substantial variation across studies (I² = 95.4%), with a 95% prediction interval ranging from −0.22 to 0.61. What this tells us is that eco-anxiety does not uniformly predict action across contexts; the variability is considerable and meaningful. Moderator analyses offered important clarification. The association proved significantly stronger for public and collective behaviors, such as activism and advocacy (r = 0.36), compared to private sphere actions (r = 0.22). Beyond this, effects were more robust in adult samples (r = 0.30) than among adolescents (r = 0.18). These findings suggest something worth emphasizing: eco-anxiety appears to function not merely as a pathological burden but as an adaptive, context-sensitive correlate of collective engagement. Put differently, the distress people experience in response to climate change may channel productively into systemic action, particularly when social and collective pathways are available. What this means for practice is significant. Future interventions, in this perspective, should focus on channeling climate distress toward collective, structural engagement rather than defaulting to individual behavioral prescriptions alone. Full article

The efficient conversion of CO₂ into valuable chemicals using highly efficient, environmentally friendly, and renewable heterogeneous catalysts is paramount for the progression of a carbon circular economy. In pursuit of this goal, this study introduces a metal-free, scalable melamine-based organic polymer catalyst designed to integrate CO₂ adsorption with customizable functional properties. Employing both solid-state thermal synthesis (SST) and hydrothermal methods, we synthesized three amine-based hydrogen bond donor catalysts, thereby balancing environmentally conscious practices with scalable synthesis: MCA, a high-nitrogen-content polymer derived from trichlorocyanuric acid; MCA-SST; and MTAB, a triazine-trichlorocyanuric acid polymer. Under mild conditions (100 °C, 0.1 MPa, 24 h), MCA demonstrated superior catalytic performance in the CO₂ cycloaddition of epichlorohydrin, achieving a 99% conversion rate, significantly surpassing MCA-SST (60%) and MTAB (78%). MCA’s high specific surface area and structural integrity facilitate efficient catalysis under mild conditions, and it retains 79% of its initial activity after five cycles, indicating exceptional stability. These results suggest that while the incorporation of secondary amines and increased nitrogen content generally promote the reaction, densely packed adjacent secondary amine linkages can induce repulsion between nitrogen atoms, thereby weakening active sites and reducing catalytic activity. Consequently, this study not only presents MCA as a novel metal-free catalyst exhibiting remarkable performance in catalyzing CO₂ cycloaddition under ambient pressure and mild conditions, but also elucidates the structure–activity relationship between secondary amine density and catalytic activity. This work provides a deeper mechanistic understanding and offers a theoretical foundation for future rational catalyst design. Full article

Under the background that urban–rural integrated development continuously deepens and the common prosperity goal continuously advances, systematically identifying the actual results of urban–rural integrated development and its influence mechanism on common prosperity holds important significance for understanding regional development differences and optimizing policy implementation paths. Based on land use data, NTL data, and POI facility data from 2013 to 2025, this study comprehensively employs spatial analysis and deep learning methods to conduct an empirical analysis on the spatiotemporal evolution characteristics and coupling relationship of urban–rural integrated development and common prosperity levels from dimensions including urban–rural spatial form evolution, economic activity intensity, and public service facility diversity. The research results indicate that urban–rural integration significantly promotes urban spatial expansion and the improvement in overall economic activity levels during the study period, but the difference in development magnitude among different regions remains obvious. The common prosperity level generally presents a rising trend, but it highly concentrates in the Pearl River Delta and city–county center areas in space, and the promotion effect of urban–rural integration on common prosperity exhibits obvious characteristics of regional heterogeneity, stages, time lags, and diminishing marginal effects. This study considers that urban–rural integration does not inevitably and synchronously transform into an elevation in common prosperity levels. Combining regional development basis and structural conditions to optimize urban–rural integration development paths by region and by stage and to improve the realization quality of common prosperity possesses important practical reference value. Full article

The conversion of alkanes/alkenes into useful intermediates is highly important in the chemical industry. In this study, the physicochemical properties and catalytically active forms of bismuth molybdates (BiMo) were investigated using the selective oxidation of propene to acrolein as a model reaction. The catalysts were prepared by two methods, coprecipitation and spray-drying, with emphasis on spray-drying. The catalysts were characterized using X-ray diffraction, N₂ adsorption/desorption isotherms, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The catalytic properties of the BiMo samples were studied in a conventional fixed-bed reactor operated under different reaction conditions. The one-dimensional (1D) pseudohomogeneous model was applied to describe the obtained experimental results. The experimental kinetic data were correlated with two complex kinetic models based on multiple reactions (parallel and serial reaction systems). The proposed models were verified by comparing computer simulation data with experimental laboratory results. This study aimed to extend the understanding of the relationship between catalyst composition/structure and catalyst activity/selectivity for different BiMo structures, and to propose kinetic models using two approaches based on parallel and series reactions, in line with efforts to improve the valorization of light olefins. Full article

Collagen-derived peptides are widely studied for their potential roles in skin health and anti-aging. This study applied response surface methodology to optimize the enzymatic hydrolysis of porcine skin-derived collagen oligopeptides (PCOPs) and investigate the associations between peptide characteristics and their cellular effects. The optimized hydrolysis conditions were a solid-to-liquid ratio of 1:2, 52.3 °C, 0.9% enzyme dosage, and pH 7.0. The resulting PCOPs contained 85.77% peptides with molecular weight < 1000 daltons (Da) and 9.68% hydroxyproline. In vitro, 5 mg/mL PCOPs reduced hydrogen peroxide (H₂O₂)-induced fibroblast senescence by 39.66% and significantly (p < 0.05) reduced tyrosinase activity and melanin synthesis in melanoma cells (B16). Peptidomic profiling identified 52 peptides mainly derived from type I collagen, enriched in Pro-Gly motifs. Circular dichroism analysis indicated that PCOPs primarily consisted of β-sheets (35.3%) and random coils (38.9%). These results suggest that low molecular weight, high hydroxyproline content, Pro-Gly-enriched peptides, and the predominance of β-sheet/random coil structures are associated with the observed cellular effects on fibroblast function and melanogenesis. Full article

Pure SnO₂ nanofibers were synthesized via an electrospinning method and subsequently calcined at 550 °C to investigate the structure–property relationship governing H₂S gas sensing performance. X-Ray diffraction confirmed the formation of the crystalline rutile-type SnO₂. FE-SEM and TEM methods revealed a hierarchically porous morphology with fiber diameters ranging from 70 to 160 nm. BET measurements indicated a high specific surface area of 75 m²/g, consistent with the observed porous architecture. Gas sensing measurements toward H₂S revealed a pronounced response value of 25 at 200 °C with the response time of 23 s, both superior to those recorded for acetone, ethanol, and hydrogen. The enhanced sensitivity and dynamic response are attributed to the large surface area and interconnected porous network of the nanofibers, which provide the abundant active sites and facilitate efficient gas diffusion. Full article

Background: The development of Multi-Target-Directed Ligands (MTDLs) has emerged as a significant strategy for addressing complex, overlapping pathologies such as cancer and Alzheimer’s disease (AD). This study aims to provide a robust computational framework for the design of dual-target inhibitors. Methods: This study presents an integrated and rigorous computational pipeline combining Quantitative Structure–Activity Relationship (QSAR) modeling, Molecular Docking, and Molecular Dynamics (MD) simulations with Dynamic Cross-Correlation Matrix (DCCM) analysis. Using a dataset of 57 known tubulin inhibitors, two high-performing QSAR models were developed to guide the rational design of 16 novel trimethoxyphenyl-based analogues. Results: Following ADMET and drug-likeness filtering, Lead Candidates 15 and 16 were identified. Quantitative activity predictions confirmed their enhanced potency thresholds, which were subsequently validated through static docking against β-tubulin (PDB: 4O2B) and Acetylcholinesterase (PDB: 1EVE). In total, 100 ns MD simulations and MM-GBSA calculations demonstrated superior binding stability and energetically favorable profiles for both targets, while DCCM analysis confirmed the functional synchrony of the protein–ligand complexes. Conclusions: The results provide a validated structural hypothesis for dual-target inhibition. The identified leads, 15 and 16, demonstrate strong predictive potential and are prioritized for chemical synthesis and in vitro biological evaluation. Full article

Poly(hexamethylene biguanide) (PHMB) is a polycationic antimicrobial polymer exhibiting broad-spectrum activity against bacteria, fungi, and viruses, and is widely used in medical settings for infection prevention and control. However, the relationship between chemical structure and antimicrobial activity remains unclear. In this study, we synthesised and characterised a series of polymeric biguanides with systematically varied alkyl chain lengths to examine the effects of structural variation on physicochemical properties and antimicrobial activity. H NMR spectroscopy and FTIR confirmed successful polymerisation. Solubility measurements revealed a progressive decrease in aqueous solubility with increasing alkyl chain length, consistent with increased hydrophobicity. Dynamic light scattering indicated reversible folding and unfolding of polymer chains in aqueous solution, with stabilisation at higher concentrations. Diffusion-ordered spectroscopy was used to calculate hydrodynamic diameters and polydispersity indices. Antimicrobial assays against Staphylococcus aureus and Pseudomonas aeruginosa showed that polymers containing heptamethylene and octamethylene chains exhibited the highest antibacterial activity, whereas tetramethylene- and pentamethylene-containing polymers showed greater fungicidal activity against Candida albicans. Highly hydrophobic polymers showed increased aggregation, resulting in reduced antimicrobial efficacy. Overall, these results indicate that both charge density and alkyl chain length are key determinants of antimicrobial activity. This polymeric biguanide series provides a platform for further investigation of structure–activity relationships and mechanisms of action against pathogenic microorganisms and their biofilms. Full article

To address the technical challenge where traditional high-pressure, large-flow emulsion pump stations cannot adapt to the drastic flow rate changes in hydraulic supports due to the fixed displacement of their quantitative pumps—leading to frequent system unloading, severe impacts, and damage—this study proposes an intelligent flow control method based on the digital flow distribution principle for actively perceiving and matching support demands. Building on this method, a compact, electro-hydraulically separated prototype with stepless flow regulation was developed. The system integrates high-speed switching solenoid valves, a piston push rod, a plunger pump, sensors, and a controller. By monitoring piston position in real time, the controller employs an optimized combined regulation strategy that integrates adjustable duty cycles across single, dual, and multiple cycles. This dynamically adjusts the switching timing of the pilot solenoid valve, thereby precisely controlling the closure of the inlet valve. As a result, part of the fluid can return to the suction line during the compression phase, fundamentally achieving accurate and smooth matching between the pump output flow and support demand, while significantly reducing system fluctuations and impacts. This research adopts a combined approach of co-simulation and experimental validation to deeply investigate the dynamic coupling relationship between the piston’s extreme position and delayed valve closure. It further establishes a comprehensive dynamic coupling model covering the response of the pilot valve, actuator motion, and backflow control characteristics. By analyzing key parameters such as reset spring stiffness, piston cylinder diameter, and actuator load, the system reliability is optimized. Evaluation of the backflow strategy and delay phase verifies the effectiveness of the multi-mode composite regulation strategy based on digital displacement pump technology, which extends the effective flow range of the pump to 20–100% of its rated flow. Experimental results show that the system achieves a flow regulation range of 83% under load and 57% without load, with energy efficiency improved by 15–20% due to a significant reduction in overflow losses. Compared with traditional unloading methods, this approach demonstrates markedly higher control precision and stability, with substantial reductions in both flow root mean square error (53.4 L/min vs. 357.2 L/min) and fluctuation amplitude (±3.5 L/min vs. ±12.8 L/min). The system can intelligently respond to support conditions, providing high pressure with small flow during the lowering stage and low pressure with large flow during the lifting stage, effectively achieving on-demand and precise supply of dynamic flow and pressure. The proposed “demand feedforward–flow coordination” control architecture, the innovative electro-hydraulically separated structure, and the multi-cycle optimized regulation strategy collectively provide a practical and feasible solution for upgrading the fluid supply system in fully mechanized mining faces toward fast response, high energy efficiency, and intelligent operation. Full article

Copper(II) coordination complexes with coumarin-derived heterocyclic ligands are promising in inorganic therapeutics for anticancer and antimicrobial applications. To establish quantitative structure–activity relationships for lead design, we studied six copper(II) complexes (Cu1–Cu6)with four- and five-coordinate geometries using Density Functional Theory, Conceptual Density Functional Theory, and visualization analyses. Geometry optimization at M06/6-31G(d)+DZVP revealed distorted coordination environments from $d^9$ Jahn–Teller effects. Tridentate $N_{2}O$-chelatedcomplexes (Cu4–Cu6) showed greater aqueous stability ($\Delta G_{solv}=-43$ to $-50$ kcal·mol⁻¹) than four-coordinate analogs ($-29$ to $-31$ kcal·mol⁻¹). CDFT global descriptors contrasted reactivity: four-coordinate Cu1–Cu2 had higher electron affinity (>4.2 eV) and electrophilicity (>5.7 eV), suggesting propensity for redox cycling and for undergoing nucleophilic attack by DNA bases, whereas Cu4–Cu6 displayed increased chemical hardness (3.43–3.54 eV) and lower electrophilicity (≈3.8 eV), implying enhanced kinetic stability and bioavailability. Frontier orbital analysis indicated ligand-to-metal charge transfer via a LUMO delocalized over the $\pi$-conjugated coumarin, facilitating intercalation by $\pi$-$\pi$ stacking. The visualization showed strong covalent bonds (blue isosurfaces) stabilizing the metal and dispersive $\pi$ interactions (green surfaces) on the ligand, enabling solvent interactions and biomolecular recognition. Tridentate $N_{2}O$ coordination thus balances electronic stability and biological reactivity, making Cu4–Cu6 promising for further study. Full article

This article analyzes the Solimene façade (Vietri sul Mare, Campania, Italy, 1952–1955). The survey, already acquired with active and passive sensors, was integrated with close-range photogrammetry of some sections of the main wall. The purpose of the new acquisitions was to generate data to inform a plug-in that, in the latest versions of the Revit software, correlates parametric and procedural environments. The focus of the study was the rationalization of the formal structure of the amphora, the heart of the main façade. Logic and geometric language guide the identification of a possible mathematical relationship aimed at parametrically modifying the model. The logical diagrams, converted into a Grasshopper preview, can be managed through graphical nodes. In the form of flowcharts (visual scripts), the finite sequence of procedural steps has the advantage of managing and modifying, in real time and in a user-friendly manner, the morphometric characteristics of the small “mummarella.” The results identify the morphometric characteristics common to a typological family composed of Vietri amphorae that, in the field of architectural design, uses the typical functions of system families. The goal is to approach sustainable and participatory design solutions by providing functions that can be graphically manipulated from within the software environment. Full article

The electronic stability and global reactivity of Cu_xSc_γ (x + y = 4) bimetallic nanoclusters were investigated within the framework of rational design of functional materials and active catalytic phases. M06-2X/def2-TZVP DFT was used for geometric optimization and electronic characterization, and global descriptors were calculated, including ΔE_gap, chemical toughness, chemical potential, and electrophilicity. The orbital contribution was analyzed using DOS/PDOS with Multiwfn; PCA and ANOVA were applied to quantify descriptor–structure relationships. The results show that adding Sc changes the cluster’s electron density and stiffness in a consistent manner, enabling distinction between more stable and more reactive configurations. In particular, Cu₃Sc is the most electronically stable, exhibiting the highest ΔE_gap, while Cu₂Sc₂ shows a more tunable electronic response, consistent with scenarios requiring greater reactivity. Multivariate analysis shows that ΔE_gap accounts for most of the electronic variability in the dataset, making it the primary descriptor for selection and design. Taken together, these results open a descriptor-guided path to designing active Cu–Sc phases for supported catalysis and to their assembly into tunable metal nanocomposites. Full article

With the rapid development of the sharing economy and the progress of social ecological civilization, social media influencers (SMIs) have garnered significant from academia and practitioners for their pivotal role in fostering pro-environmental behavioral intentions within the tourism consumption context. Drawing on the two-step flow theory, social influence theory, and social learning theory, this study establishes an integrated analytical framework to elucidate how SMIs facilitate the balance between tourism development and ecosystem preservation by activating pro-environmental behavioral behavior. This study conceptualizes the SMIs’ multi-traits as a higher-order construct (a third-order reflective structure), which integrates content-determined and personality-determined attributes, viewing SMIs’ effectiveness as a coherent system of influence rather than a series of fragmented traits. Based on survey data collected from 598 Chinese social media users, the study utilized Covariance-Based Structural Equation Modeling (CB-SEM) to test the proposed model. The results demonstrate that SMIs’ multi-traits exert significant positive effects on parasocial relationships and wishful identification, which in turn enhance individuals’ willingness to mimic. This willingness to mimic serves as a core behavioral conversion mechanism, bridging digital influence on three pro-environmental behavioral intentions: general, specific and online advocacy intentions. Furthermore, robustness analyses reveal marked heterogeneity across education- and income-based groups, indicating that the efficacy of SMI traits and the psychological-to-behavioral conversion efficiency are contingent upon the recipients’ socioeconomic resources and cognitive capital. Overall, this study characterizes social media influencer marketing as a scalable, socially driven phenomenon that can effectively activate and promote pro-environmental behavioral intentions, providing valuable insights for environmental education and sustainable tourism development in the digital age. Full article

The dry reforming of methane (DRM) is a kind of technology used for achieving resource utilization. In this paper, different Ni/SBA-15 catalysts were prepared by adjusting the pH of the impregnation solution and applying it during the DRM reaction. The relationship between the structure and catalytic performance of the catalyst was analyzed by characterization methods such as BET, XRD, H₂-TPR, H₂-TPD, XPS, TG, and Raman. The research results indicated that the dispersion of the catalyst’s active components could be regulated by changing the pH value of the impregnation solution. Among them, the Ni/SBA-15-2 catalyst exhibits good metal dispersion, and significantly enhances the activity of the catalyst. In addition, it also has strong CO₂ adsorption capacity, which improves the stability of the catalyst. At 700 °C, the conversions of CH₄ and CO₂ of the catalyst are 51% and 60%, respectively. Full article