Search Results (21,053)

Aeolian sand is the primary geological material for construction in desert regions, and its stabilization with industrial solid wastes-based geopolymer (ISWG) provides an eco-friendly treatment replacing cement. This study comparatively investigated the enhancement effects of chemical activators and expansive agents on compressive strength of aeolian sand stabilized by ISWG (ASIG). Three chemical activators—NaOH, Ca(OH)₂, and CaCl₂—along with two expansive agents—desulfurized gypsum and bentonite—were considered. Through X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, mercury intrusion porosimetry and pH values tests, the enhancement mechanisms of the additives on ASIG were elucidated. Results demonstrate that the expansive agent exhibits significantly superior strengthening effects on ASIG compared to the widely applied chemical activators. Chemical activators promoted ISWs dissolution and hydration product synthesis, thereby densifying the hydration product matrix but concurrently enlarged interparticle pores. Desulfurized gypsum incorporation induced morphological changes in ettringite, and excessive desulfurized gypsum generated substantial ettringite that disrupted gel matrix. In contrast, bentonite demonstrated superior pore-filling efficacy while densifying gel matrix through a compaction effect. These findings highlight bentonite superior compatibility with the unique microstructure of aeolian sand compared to conventional alkaline activators or expansive agents, and better effectiveness in enhancing the strength of ASIG. Full article

Driven by the new wave of technological revolution and industrial transformation, firms are accelerating strategic change to gain new competitive advantages. Situated within a complex adaptive system, firms must adapt to highly dynamic and uncertain external environments by adjusting executive cognitive structures, reconfiguring resources and capabilities, and strengthening collaboration with industrial ecosystem elements; hence, digital strategic change is characterized by continuous evolution. Using a sample of Chinese A-share listed firms from 2015 to 2023, this study develops a “cognition–capability–strategy” pathway model grounded in upper echelons theory and dynamic capabilities theory to examine how executive cognitive styles, i.e., cognitive flexibility and cognitive complexity, drive digital strategic change via absorptive capacity and how environmental dynamism moderates these relationships. The findings show that executive cognition, as a decision node in strategic change, can dynamically adjust firms’ strategic paths by activating absorptive capacity in rapidly changing external information environments; environmental dynamism differentially affects the two cognitive styles. Heterogeneity tests further indicate that the role of executive cognition varies significantly with regional digital economy development levels, firm life cycle, and industry factor intensities. The study reveals how firms can respond to high environmental uncertainty through cognition–strategy alignment and resource capability reconfiguration in a complex adaptive system, providing theoretical references and practical insights for emerging economies to advance digital transformation and enhance competitiveness. Full article

The increasing complexity of managing maintenance activities across geographically dispersed hospitality facilities necessitates advanced digital solutions capable of effectively balancing operational costs and service quality. This study addresses this challenge by designing and validating an intelligent Prescriptive Maintenance module, leveraging advanced Reinforcement Learning (RL) techniques within a Digital Twin (DT) infrastructure, specifically tailored for luxury hospitality networks characterized by high standards and demanding operational constraints. The proposed framework is based on an RL agent trained through Proximal Policy Optimization (PPO), which allows the system to dynamically prescribe preventive and corrective maintenance interventions. By adopting such an AI-driven approach, platforms are the enablers to minimize service disruptions, optimize operational efficiency, and proactively manage resources in dynamic and extended operational contexts. Experimental validation highlights the potential of the developed solution to significantly enhance resource allocation strategies and operational planning compared to traditional preventive approaches, particularly under varying resource availability conditions. By providing a comprehensive and generalizable representation model of maintenance management, this study delivers valuable insights for both researchers and industry practitioners aiming to leverage digital transformation and AI for sustainable and resilient hospitality operations. Full article

Alongside the gradual progress of industrialization and the continuous development of human society, the problems of environmental pollution and energy crisis have become increasingly prominent. Semiconductor photocatalysis is a promising solution to these challenges. The photocatalytic reduction of CO₂ by TiO₂ to produce carbon monoxide and methane is a process which has been identified as a means of developing clean energy. In this paper, two-dimensional TiO₂ (2D-TiO₂) was synthesized via a one-step solvothermal method, and one-dimensional TiO₂ (1D-TiO₂) was obtained through a hydrothermal process. Their photocatalytic CO₂ reduction performances were systematically investigated. The results show that 2D-TiO₂ exhibits superior catalytic activity compared to 1D-TiO₂, which can be attributed to its lamellar structure, larger specific surface area, and improved hydrophilicity, providing more active sites and faster reaction kinetics. To further reveal the reaction mechanism, density functional theory (DFT) calculations were carried out using VASP with the GGA–PBE functional, PAW potentials, and a plane-wave cutoff energy of 520 eV. A 3 × 3 × 1 Monkhorst–Pack grid was used for Brillouin zone integration, and all possible adsorption configurations of CO₂*, COOH*, and CO* intermediates on the 2D-TiO₂ surface were evaluated. The results confirm that 2D-TiO₂ stabilizes key intermediates more effectively, thereby lowering the energy barrier and facilitating CO₂ reduction. These findings demonstrate that structural modulation of TiO₂ significantly influences its photocatalytic performance and highlight the great potential of 2D-TiO₂ for efficient CO₂ conversion and clean energy applications. Full article

The development of advanced wound dressing materials with enhanced antibacterial properties is critical for improving patient outcomes and reducing infection risks. This study introduces a novel bio-based aerogel composed of copper-crosslinked alginate and hyaluronic acid, synthesized using supercritical gel drying techniques. Alginate and hyaluronic acid polymers are widely used in the pharmaceutical and medical industries because of their nontoxicity, biodegradability, and biocompatibility. This study aimed to create an aerogel that could be used as a potential wound dressing material by crosslinking hyaluronic acid and alginate with copper. The bio-based aerogel was prepared by ionic gelation and supercritical gel drying. The prepared materials were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), BET surface area analysis, and energy-dispersive X-ray fluorescence (XRF). Moreover, the aerogel wound dressing properties were evaluated in terms of fluid uptake and antibacterial activity against S. aureus and E. coli. The physicochemical characterization of the prepared aerogels revealed their unique structural and morphological features, which are influenced by copper ion concentration and crosslinking time. Regarding their wound dressing evaluation, both aerogel and hydrogel were found to have antibacterial properties when tested on S. aureus with inhibition zones of (36 mm, 23 mm) and E. coli (31.6 mm, 21 mm) for hydrogel and aerogel, respectively. Also, excellent fluid uptake was found to reach up to 743%. These findings underscore the potential of copper-crosslinked alginate–hyaluronic acid aerogels as innovative wound dressing materials that combine superior antibacterial efficacy with excellent fluid management, paving the way for improved wound healing solutions. Full article

The H9N2 virus has severely harmed the livestock and bird farming industry. Currently, it is mainly prevented through vaccination immunization. However, conventional vaccines often fail to induce durable immune responses and long-lasting immunoprotection. In this research, we used Simvastatin (Sim) and CpG as adjuvants for the H9N2 inactivated vaccine to evaluate the vaccine’s immunogenicity in chickens. We evaluate vaccine immunogenicity through antibody testing, T lymphocyte phenotyping, and RNA-sequencing analysis. The results indicated that the Sim + CpG/H9N2 formulation significantly enhanced specific IgY and hemagglutination inhibition (HI) antibody titers. It also increased the proportions of CD4⁺ T cells and CD8⁺ T cells, promoted immune organ development, and stimulated the formation of germinal centers. RNA-sequencing analysis revealed that Sim + CpG/H9N2 vaccination significantly upregulated immune-related genes, which were enriched in pathways associated with stress response activation, immune cell recruitment, and inflammatory signaling. Overall, these findings demonstrate that Sim + CpG/H9N2 markedly enhances the immunogenicity of the inactivated H9N2 vaccine and provides new insights into the application of vaccine adjuvants for improved immune protection. Full article

Building upon recent advances in tactile sensing platforms such as OptoSkin, this research introduces an enhanced multi-touch sensor design that integrates Frustrated Total Internal Reflection (FTIR) technology with embedded Time-of-Flight (ToF) sensors for superior performance. Utilizing a 2 mm thick poly(methyl methacrylate) (PMMA) acrylic light guide with an area of 200 × 300 mm², the system employs the AMS TMF8828 ToF sensor both as the illumination source and the receiver. The selected PMMA, with a refractive index of 1.49, achieves an optical field of view (FoV) of approximately 32 degrees for the ToF receiver and enables signal propagation with minimal optical loss. Remarkably, a single ToF sensor can cover an active area of 195 cm² with a linear resolution of approximately 1 cm and an angular resolution of up to 3.5 degrees. This configuration demonstrates not only the feasibility of direct FTIR–ToF integration without the need for external cameras or electrode arrays but also highlights the potential for precise, scalable, and cost-effective multi-touch sensing over large surfaces. The proposed system offers robust performance even under direct sunlight conditions, setting a new benchmark for advanced tactile interface development across consumer electronics, industrial control, and robotic skin applications. Full article

Freshwater ecosystems are a significant entity that govern the livelihood of people and are an important source of food, employment, and recreation. However, climate change is impacting freshwater ecosystems by altering their natural habitats. The purpose of this review is to highlight the vulnerability of freshwater fish to climate change. Climate change is invariably affecting natural ecosystems everywhere and in every part of the world, but these threats are more severe in Pakistan. Freshwater fish are important biotic drivers of freshwater ecosystems. Unfortunately, uncertain climate changes and anthropogenic activities have led to a decline in the diversity of these fishes. Rising temperatures, melting glaciers, changes in seasonal patterns, disturbances in the natural flow of rivers, pollution, and invasive species are major threats to native freshwater fish fauna, leading to a decline in fish diversity and population. Tor putitora, Glyptothorax kashmirensis, and Triplophysa kashmirensis are some of the species that are critically endangered in Pakistan due to these factors. In recent decades, insufficient attention has been paid to the freshwater ecosystem. This review of threats to the endemic fish species in this region is presented so that the government and policymakers can use this information as part of their management and conservation policy, thus safeguarding Pakistan’s fish industry. Environmental DNA (eDNA) biomonitoring is a new technique for assessing biodiversity and species distribution and can be useful for conserving biodiversity in this region. Another purpose of this review is to introduce this new conservation strategy to Pa Full article

In the race for industrialization and urbanization, the concentration of greenhouse gases like CO₂ and CH₄ is growing rapidly and ultimately resulting in global warming. An Ni-based catalyst over MgO support (Ni/MgO) offers a catalytic method for the conversion of these gases into hydrogen and carbon monoxide through the dry reforming of methane (DRM) reaction. In the current research work, 1–4 wt% strontium is investigated as a cheap promoter over a 5Ni/MgO catalyst to modify the reducibility and basicity for the goal of excelling the H₂ yield and H₂/CO ratio through the DRM reaction. The fine catalytic activities’ correlations with characterization results (like X-ray diffraction, surface area porosity, photoelectron–Raman–infrared spectroscopy, and temperature-programmed reduction/desorption (TPR/TPD)) are established. The 5Ni/MgO catalyst with a 3 wt.% Sr loading attained the highest concentration of stable active sites and the maximum population of very strong basic sites. 5Ni3Sr/MgO surpassed 53% H₂ yield (H₂/CO ~0.8) at 700 °C and 85% H₂ yield (H₂/CO ratio ~0.9) at 800 °C. These outcomes demonstrate the catalyst’s effectiveness and affordability. Higher Sr loading (>3 wt%) resulted in a weaker metal–support contact, the production of free NiO, and a lower level of catalytic activity for the DRM reaction. The practical and cheap 5Ni3Sr/MgO catalyst is scalable in industries to achieve hydrogen energy goals while mitigating greenhouse gas concentrations. Full article

This paper highlights recent activities associated with the design of an uninstalled open fan propulsor for next-generation civil aircraft in the high-subsonic flight regime. The concept comprises a transonic propeller–rotor and a subsequent guide vane, which are both subject to pitch-variability in order to account for the strong variations in flight conditions over the entire mission profile. The engine-scale design aimed for high technological maturity and to comply with a high number of industrially relevant requirements to ensure a competitive design, meeting performance requirements in terms of high efficiency levels at cruise and maximum climb conditions, operability in terms of stability margins, good acoustic characteristics, and structural integrity. During the design iterations, rapid 3D-RANS-based optimisations were only used as a conceptual design tool to derive sensitivities, which were used to support and justify major design choices in addition to established relations from propeller theory and common design practice. These design-driven optimisation efforts were complemented with more sophisticated CFD analysis focusing on rotor tip vortex trajectories and resulting in unsteady blade row interaction to optimise the guide vane clipping, as well as investigations of the entire propulsor under angle-of-attack conditions. The resulting open fan design will be the very basis for wind tunnel experiments of a downscaled version at low and high speed. Full article

The use of cyanobacteria has gained considerable interest in many industries, including the cosmetic industry, due to its rich array of bioactive metabolites. This study evaluates the in vitro photoprotective properties and the effect of Cylindrospermum alatosporum (NR125682) and Loriellopsis cavernicola (NR117881) extracts on slowing down the enzymes associated with skin aging. Various crude extracts were prepared using hexane, dichloromethane, and ethanol solvents. The resulting crude extract solvents were completely distilled to obtain their bioactive compounds, based on selected polarities. The sulfhydryl content of the crude extracts was determined and the aging-associated enzymes’ activity (collagenase, elastase, hyaluronidase, and tyrosinase) in the crude extracts was investigated. Furthermore, the in vitro photoprotective activity of the extracts was assessed by measuring UVA and UVB photoprotection. Most of the extracts contained varying amounts of sulfhydryl compounds (10.88–78.15 mg/g). All of the extracts demonstrated in vitro inhibitory activity against tyrosinase, hyaluronidase (IC₅₀ 6 µg/mL), and collagenase (IC₅₀ 50–70 µg/mL); weak elastase inhibitory activities were also observed. The crude extracts also showed appreciable UVA and UVB photoprotective activity. Meanwhile, L. cavernicola extracts demonstrated the highest UVB photoprotective activity (SPF 14.67–78.96). It is noteworthy that the crude extracts possessed anti-skin-aging potency with notable photoprotective capability. Full article

Alkaline pectate lyases hold significant promise for various industrial applications, including the degumming processes in papermaking and textiles. In this study, a novel pectinase, PelA, derived from a strain of Paenibacillus borealis, was characterized both at the molecular level and through enzymatic analysis. This enzyme represents a distinct cluster diverging from the well-characterized Bacillus pectinases and exhibits molecular activity under alkaline conditions, with an optimal pH of 9.5. It can be classified as an endo-(1,4)-pectate lyase, capable of cleaving the α-1,4 glycosidic bonds of polygalacturonic acid via a trans-elimination mechanism. Notably, the addition of the metal ion Ca²⁺ did not enhance enzyme activity. To achieve high-level secretory expression and improve its economic viability for bioapplications, the gene copy number of pelA in the host genome was increased by constructing tandem pelA gene expression cassettes. Following optimization of cultivation conditions and monitoring of cell growth, the recombinant strain harboring the multi-copy pelA gene attained an expression level of 7520 U/mL in a bioreactor. This study successfully achieved high-level secretory expression of an alkaline pectinase, thereby enhancing its potential for industrial bioapplications and providing a reference for future research on the heterologous expression of target genes. Full article

Enzyme entrapment in alginate hydrogel microbeads is an effective method of immobilization for industrial applications, but many fabrication methods for alginate microbeads involve oil, organic solvents, or high temperatures that reduce enzymatic activity. In this study, we employed an oil- and solvent-free gas-shearing technique to prepare alginate microbeads for the entrapment of Candida rugosa lipase (CRL), thereby minimizing thermal- and solvent-induced inactivation. To enhance immobilization efficiency and reusability, the effects of gas flow rate, alginate concentration, and cross-linking metal ions were systematically investigated. CRL entrapped in Ba- and Fe-alginate microbeads showed superior immobilization yield, activity retention, and activity recovery compared with CRL entrapped in conventional Ca-alginate microbeads. Notably, both Ba- and Fe-alginate microbeads exhibited significantly enhanced stability, with half-lives up to 127-fold greater than that of free CRL at 60 °C, and maintained substantially higher pH stability across the tested range. Ba-alginate microbeads provided greater pH stability and substrate affinity, whereas Fe-alginate microbeads demonstrated enhanced thermal stability and catalytic turnover. These findings highlight gas-shearing as a scalable and gentle fabrication method for producing high-performance alginate microbeads with tunable properties, making them suitable for enzyme entrapment in diverse biocatalytic applications. Full article

Although caries is declining in industrialized countries, early childhood caries and molar–incisor hypomineralization (MIH) remain clinically relevant. To meet the demand for effective and well-tolerated preventive strategies, hydroxyapatite (HAp) has gained attention as a biocompatible, fluoride-free agent. A structured narrative review was conducted to evaluate recent clinical evidence on the use of HAp. A PubMed search identified clinical trials from the past five years that investigated HAp-based products. Studies were included if they reported clinical outcomes related to remineralization, caries prevention, or desensitization. Fifteen clinical studies met the inclusion criteria. HAp seems to be a safe and effective alternative to flouride, especially for children or individuals at risk of overexposure. While both agents show similar efficacy in caries prevention, HAp may offer additional advantages in managing hypersensitivity and MIH. Compared to other remineralizing agents, such as calcium sodium phosphosilicate, HAp demonstrated comparable efficacy. Combination therapies show the most promising results. Future research should explore synergies of active ingredients and include standardized long-term studies to substantiate the clinical relevance of HAp. Full article

The global gold extraction industry has been reported to use cyanide-based recovery processes, which pose environmental effects on water resources. The study examined Coptodon zillii liver rhodanese from a gold mining-impacted reservoir with a specific focus on the enzyme’s critical function in cyanide detoxification. Rhodanese was purified using successive chromatographic techniques with 5.4 U/mg specific activity and 3.1-fold purification. The molecular weight of the native enzyme was 36 kDa, and the subunits were 17 kDa, indicative of a dimeric structure. Optimal enzymatic activity was recorded at pH 8.0 and 50 °C. The effect of metal ions was significantly varied: the activity was inhibited by BaCl₂, CaCl₂, NaCl, and MgCl₂, and KCl enhanced performance. The kinetic determinations showed Michaelis-Menten kinetics with a Km of 20.0 mM for sodium thiosulfate and 25.0 mM for potassium cyanide. The enzyme’s minimal activity was identified toward 2-mercaptoethanol, ammonium persulfate, and ammonium sulfate, but with evidence of preference for thiosulfate utilization under the substrate specificity tests. The major interactions between the enzyme and the substrate were revealed by the molecular docking experiments. These showed Glu159, Gln161, and Arg173 formed important hydrogen bonds with thiosulfate, while Arg156 and Val172 were also involved. Other substrates are bound to Gln121 and Trp139 residues with much lower binding energy than thiosulfate. The findings increase our understanding of biochemical adaptation process knowledge in anthropogenically stressed environments, showing strategies of ecological resilience. The characterized enzymatic features showed potent cyanide detoxification potential, and the possible applications are in bioremediation strategies for mining-impacted aquatic ecosystems. Full article