Search Results (3,937)

Primary succession following glacier retreat provides a natural system for testing whether soil development simply shifts fine roots along a single acquisitive–conservative axis orinstead changes the nutrient-acquisition pathway that dominates at the community level. We hypothesized a stage-dependent sequence, from substrate-limited exploration, to transient morphological capture, and finally to rhizosphere-mediated biochemical mobilization. To test this idea, we quantified fine-root morphology, absorptive-transport partitioning, anatomy, phosphatase activity, exudation, community-scale belowground structure, and soil and rhizosphere properties across woody communities representing approximately 20, 40, and 90 years since deglaciation in the Hailuogou Glacier foreland. Across succession stages, bulk density and pH declined, whereas field capacity, soil carbon, and soil nitrogen increased, indicating rapid development of the belowground resource environment. Fine-root strategies did not fall along a single acquisitive–conservative continuum. Instead, morphological nutrient capture peaked at intermediate succession: the 40-year stage had the highest specific root length, specific root area, absorptive-to-transport root length ratio, and root nitrogen concentration. In contrast, the 90-year stage showed lower specific root length but higher dry matter content, thicker cortex, greater standing fine-root biomass, larger rhizosphere volume, higher phosphatase activity, and greater area-based carbon exudation. This late-successional syndrome coincided with stronger extracellular enzyme activity, larger dissolved organic carbon and nitrogen pools, and higher microbial biomass, despite negative net nitrogen mineralization. Species-level analyses showed that biochemical-input traits were jointly shaped by successional stage, species identity, and their interaction. Together, these results show that primary succession did not simply increase or decrease root acquisitiveness. Instead, as soils developed, it changed the nutrient-acquisition pathway that dominated, with direct implications for nutrient cycling and vegetation dynamics in rapidly developing glacier-foreland ecosystems. Full article

Background: The coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, remains a significant threat to global health. This continued threat is due to the emergence of new variants, the immune system’s limited ability to respond, and the limited effectiveness of available treatments for all individuals. Therefore, leveraging drug repurposing, a fast and inexpensive way to find other drugs that have already been shown to be safe and efficacious, becomes useful. This study leverages ADMET profiling, network pharmacology, and molecular docking to evaluate the repurposing of Product Nkabinde for COVID-19 treatment. Methods: ADMET analysis involving the bioactive phytochemicals of PN was evaluated for pharmacokinetic appropriateness and drug-likeness. Using topological analysis, a network of protein–protein interactions was built to identify hub genes, and predicted compound targets were intersected with COVID-19-associated genes to find shared targets. Their biological importance was characterized using functional enrichment analysis. The binding affinities of PN phytochemicals against hub proteins and SARS-CoV-2 viral proteases (Mpro and PLpro) were assessed by molecular docking using AutoDock Vina. To confirm docking accuracy, co-crystallized ligands were redocked using Schrodinger 2022-1. The multi-target therapeutic potential of PN in COVID-19 was assessed using this integrative network pharmacology and molecular docking technique. Results: Molecular docking demonstrated that PN phytochemicals displayed robust and persistent binding affinities for both viral and host targets. Oleanolic acid showed the best affinity toward Mpro (−12.9 kcal/mol vs. −8.3 kcal/mol), while quercetin-3-O-β-D-(6′-galloyl)-glucopyranoside showed better binding to PLpro (−8.4 kcal/mol vs. −6.4 kcal/mol). Procyanidin B2 toward HCK (−10.5 vs. −7.9 kcal/mol), diosgenin toward EGFR (−9.4 vs. −8.4 kcal/mol), rutin toward SRC (−10.5 vs. −7.8 kcal/mol), and pimelea factor P2 toward PIK3R1 (−11.0 vs. −8.2 kcal/mol) all showed significantly higher affinities than their corresponding co-crystallized ligands. Furthermore, procyanidin B2 demonstrated consistent binding to STAT1 and STAT3, confirming its role in modulating immune signals. Most of the PN phytochemicals show advantageous pharmacokinetic properties, including elevated anticipated gastrointestinal absorption and adherence to Lipinski’s rule of five, signifying favorable oral bioavailability and drug-like properties. Moreover, PN exhibits a remarkable multi-target binding capacity against both SARS-CoV-2 proteases and key host signaling proteins involved in immune regulation and inflammatory responses, as determined by this integrative network pharmacology and molecular docking investigation. Conclusions: PN’s prospects as a host-directed, antiviral treatment for COVID-19 are demonstrated by its coordinated modulation of the PI3K/AKT, JAK–STAT, SRC-family kinase, EGFR, and SYK pathways. These results necessitate further experimental and clinical validation, providing a solid computational basis for repurposing PN in the treatment of COVID-19. Full article

It remains unclear whether and how digital marketing affects corporate green innovation. Focusing on Chinese listed companies, this study investigates the relationships between digital marketing, absorptive capacity, and green innovation. Using panel data from 2012 to 2023 and a fixed-effects model, we found that digital marketing significantly boosts green innovation and that absorptive capacity mediates this relationship. Moreover, managerial performance pressure strengthens the positive effect of digital marketing on absorptive capacity, whereas environmental uncertainty weakens it. A heterogeneity analysis reveals that this positive effect is more pronounced in large enterprises, non-heavily polluting industries, and regions with a higher level of digital economic development. This study fills a gap in the literature regarding how digital marketing drives green innovation, extends the Knowledge-Based View, and provides empirical evidence and practical guidance for corporate green transformation and policy-making. Full article

Hydrogels have emerged as a crucial category of polymeric materials in materials science due to their three-dimensional network structure and remarkable capacity for water absorption and retention. However, conventional single-function hydrogels do not satisfy the increasing demands of advanced applications in biomedicine and environmental engineering. This paper focuses on the design, preparation, and performance characterization of nanofiber-reinforced polyacrylamide hydrogels to overcome this limitation. A bilayer structure, consisting of tensile layers and actuator layers based on a polyacrylamide/sodium alginate (PAM/SA) matrix integrated with functional materials, was developed. Nanocellulose (CNF) was incorporated to regulate mechanical properties by adjusting its content ratio with PAM, while poly-N-isopropylacrylamide (PNIPAM) and multi-walled carbon nanotubes (MWCNTs) were added to confer photothermal responsiveness. The deformation of the hydrogel was induced by temperature changes resulting from infrared illumination. The results indicate that the CNF-reinforced hydrogels exhibit enhanced mechanical strength—with the tensile strength reaching 17 kPa (89% higher than pure PAM) and fracture strain approaching 900% when the CNF content is 0.44 wt.% and PAM/SA mass ratio is 4:1—and they display reversible thermosensitive responses (reaching 60 °C within 100 s under near-infrared irradiation) following the incorporation of carbon nanotubes. This paper presents a novel strategy for the development of multifunctional hydrogel-based actuated systems, expanding the application potential of hydrogels in human motion tracking and drug delivery. Full article

The global energy transition has fundamentally reshaped the conditions under which green trade generates sustainable productivity gains. This study investigates whether renewable energy adoption mediates the relationship between green trade export (GTE) and green total factor productivity (GTFP) across 37 OECD economies over 2003–2023. Employing two-way fixed-effects panel regression, dynamic System-GMM estimation, and Hansen’s panel threshold regression with 500 bootstrap iterations, we identify a nonlinear, inverted-N-shaped relationship between GTE and GTFP. Sequential threshold testing reveals a statistically significant double threshold structure: a first clean energy threshold at approximately 8.72% of total final energy consumption and a second threshold at approximately 24.63%, yielding three distinct productivity regimes. Below the first threshold, green trade suppresses GTFP through pollution displacement and insufficient absorptive capacity; between thresholds, green trade exerts a significant positive productivity effect driven by clean technology diffusion and innovation spillovers; above the second threshold, the positive effect moderates, consistent with diminishing returns to green technology absorption. Heterogeneity analysis reveals that early-stage energy transitioners bear disproportionately larger productivity penalties, while advanced transitioners capture stronger above-threshold gains. These findings underscore that trade liberalization alone is insufficient—sustainable productivity growth requires concurrent and targeted investment in renewable energy infrastructure under the post-Paris Agreement framework. Policy implications are presented as evidence-consistent hypotheses, acknowledging that the observational panel framework precludes definitive causal claims pending corroboration from quasi-experimental designs. Full article

In order to maximize the use of low-temperature heat sources for refrigeration, a Li-Br absorption chiller combined with single-effect absorption refrigeration cycle and two-stage absorption refrigeration cycle (STAC) was developed. Experimental research on STAC was conducted on a prototype with a refrigeration capacity of 500 KW. A numerical model validated by experimental data was used to study the refrigeration performance of STAC under variable operating conditions. Compared to single-effect units and two-stage units, STAC demonstrates remarkable heat source conservation capability and adaptability to a broad spectrum of heat source temperatures. This advantage renders the STAC unit more adaptable to new energy or waste heat scenarios characterized by unstable heat sources. As the inlet temperature of the hot water increases, the temperature difference between the inlet and outlet of the hot water also increases. When the inlet temperature of the hot water is 70 °C, 90 °C and 120°C, the temperature difference between the inlet and outlet of the hot water is 10 °C, 30°C and 70 °C, respectively. Both increasing the inlet temperature of hot water and decreasing the temperature of cooling water will enhance the cooling capacity and coefficient of performance (COP) of STAC. As the flow rate of chilled water increases, the refrigeration capacity of STAC will also increase, but the COP will first increase and then decreases Full article

Background/Objectives: The purpose of this study was the chemical design, synthesis, and evaluation of the antimicrobial and antibiofilm potentials of 20 novel thiazolyl-methylthio-thiadiazole hybrid compounds (6a–j and 8a–j). Methods: The compounds were designed as structural analogues of halicin with two points of variation and were synthesized through a process with multiple condensation steps. The compounds were evaluated in vitro through MIC determinations for the antimicrobial activity and percentage of biofilm inhibition, and in silico, respectively, through molecular docking, druggability, and ADMETox prediction. A 2D-QSAR study was conducted for antimicrobial activity using the Free-Wilson model. Results: In terms of antibacterial activity, all compounds displayed important activity on the tested strains (MICs = 15.62–250 μg/mL), except against Staphylococcus aureus. Regarding the antifungal activity, the effect against Candida albicans was similar to fluconazole in most cases (MIC = 15.62 μg/mL). With respect to the antibiofilm activity, the most effective activity was registered against the Pseudomonas aeruginosa biofilm. The in vitro results for the antibacterial activity against Escherichia coli were correlated with the observations drawn in the molecular docking study on the ATPase domain of the GyrB subunit of E. coli. The in silico predictions of the molecular properties concluded that all compounds have good druggability properties, while the ADMETox predictions concluded that the compounds could have low gastrointestinal absorption and blood–brain barrier permeation capacity, but raised safety flags (e.g., hepatotoxicity and high acute oral toxicity). The 2D-QSAR study concluded that the thiazolyl-methylthio-thiadiazole scaffold had the highest contribution to antimicrobial activity in almost all cases. Conclusions: The two series of compounds highlight the impact of structural modulations of the scaffold and its substituents on the investigated biological activities. Full article

Metabolic dysfunction, a hallmark of diet-induced obesity (DIO), is increasingly attributed to alterations in intestinal nutrient and electrolyte transport. Yet the mechanisms that drive obesity-associated functional alterations of intestinal transporters remain incompletely understood. In this context, the effects of a high-fat diet (HFD) induced obesity on sodium-dependent glucose co-transporter 1 (SGLT1), Na⁺/H⁺ exchanger 3 (NHE3), and Cl⁻/HCO₃⁻ exchangers (DRA/PAT1), the primary glucose, sodium, and chloride absorptive pathways in mice small intestinal villus cells, were investigated. SGLT1 activity significantly increased in intact villus cells and brush border membrane vesicles (BBMV) from HFD-fed mice. Kinetic analysis demonstrated reduced Km without a change in Vmax, indicating enhanced transporter affinity. Notably, SGLT1 mRNA and protein expression, including BBM localization, were unchanged. Basolateral Na⁺/K⁺-ATPase activity was decreased, excluding enhanced Na⁺ gradient generation as the mechanism for SGLT1 stimulation. In contrast, DRA/PAT1 activity was significantly increased in HFD-fed mice, and kinetic studies revealed elevated Vmax without a change in Km, indicating increased transport capacity. DRA/PAT1 mRNA, total protein, and BBM expression were all significantly elevated. NHE3 activity and expression remained unchanged. These findings demonstrate that DIO enhances intestinal glucose absorption by increasing SGLT1 affinity and chloride absorption by upregulating DRA/PAT1 transcription. These transporter-specific alterations may amplify nutrient absorption and contribute to metabolic dysregulation in obesity. Full article

Developing sustainable and fire-resistant infrastructure is a critical technological, economic, and environmental challenge for modern construction stakeholders. Traditional cementitious composites experience severe microstructural degradation under extreme temperatures and their high carbon footprint exacerbates global environmental concerns. While the individual high-temperature behaviors of supplementary cementitious materials and fibers have been widely studied, the long-term synergistic mechanisms of high-volume fly ash combined with steel fibers under extreme thermal shock remain critically underinvestigated. To address this urgent need and bridge this scientific gap, hybrid mortars incorporating high-volume fly ash (FA) and steel fibers (SF) were tested under prolonged curing (150 days) and extreme heat (up to 600 °C). In terms of engineering and construction effects, the optimal CFA50-F hybrid composite delivered the highest residual compressive and flexural capacities (retaining nearly 60% of its late-age compressive strength at 32.00 MPa), preserved acoustic continuity (restricting UPV loss to 41.4%), and severely restricted high-temperature capillary permeability (limiting the water absorption increase to 49.7%) compared to traditional plain matrices. Scientifically, this superior resistance is governed by a two-step protective mechanism. High-volume FA chemically stabilizes the matrix by consuming vulnerable portlandite and preventing the formation of expansive calcium oxide. Simultaneously, ultra-fine FA particles physically densify the interfacial transition zones, securely anchoring the steel fibers and preventing premature high-temperature pull-out, while enabling the fibers to bridge thermally induced macro-cracks successfully. Environmentally and economically, an annualized service-life Life Cycle Assessment (LCA) revealed that substituting 50% of the cement with FA completely subsidizes the production-stage carbon penalty of the metallic reinforcement. By extending the operational lifespan to 40 years, the CFA50-F composite achieves a net 27% reduction in annualized global warming potential, providing a highly sustainable and cost-effective material solution. Full article

Dry rooms used in battery and semiconductor research facilities require ultra-low dew-point environments, which demand significant thermal energy for desiccant rotor regeneration. In steam-regenerated systems, condensate discharged through steam traps partially evaporates due to pressure reduction, generating flash steam that is typically released into the atmosphere, resulting in substantial energy losses. This study investigates the generation and recovery potential of flash steam in dry room HVAC systems. Field measurements were conducted for 18 steam-regenerated desiccant air handling units installed in a medium-scale research facility (total floor area: 43,000 m²) in southern Gyeonggi Province, Korea. Boiler operation data—including feedwater flow rate, pressure, and operating time—were analyzed over a six-month period from March to August 2025. The results showed that the average flash steam generation rate was approximately 1.16 ton/h, corresponding to 8.56% of the average feedwater flow rate. Two recovery methods were evaluated: a steam jet thermocompressor (SJT) and an exhaust vapor condenser (EVC). The analysis revealed that the EVC system provides a more practical solution for medium-scale dry rooms because it does not require high-pressure primary steam. By recovering flash steam using three EVC units, an average heat recovery of 724 kW was achieved. The recovered heat can produce 86 °C hot water, which can be utilized as a driving heat source for an absorption chiller, generating approximately 507 kW of cooling capacity. This configuration partially offsets the cooling load of existing centrifugal chillers, thereby reducing electrical energy consumption. In addition, the proposed system eliminates atmospheric discharge of flash steam, mitigating the visible white plume phenomenon commonly observed in industrial facilities. The results demonstrate the technical feasibility of integrating flash steam recovery with absorption cooling to enhance energy efficiency in medium-scale dry room HVAC systems. Full article

6063 aluminum alloy has broad application prospects in aerospace and microelectronic thermal management systems due to its good thermal conductivity and moderate strength. However, its extremely high hot cracking susceptibility during the laser powder bed fusion (LPBF) process limits the direct manufacturing of complex components. This study proposes a strategy combining material composition modification with advanced structural design. By introducing TiH₂ nanoparticles (1.0~4.5 wt.%) to modify the 6063 aluminum alloy powder, Diamond-type porous structures based on triply periodic minimal surfaces (TPMS) were successfully fabricated using LPBF technology. The results show that the introduction of TiH₂ significantly suppresses the solidification cracking of the aluminum alloy. The underlying mechanism is that the L1₂-structured Al₃Ti particles, generated by the in situ decomposition of TiH₂ in the melt pool, provide high-density heterogeneous nucleation sites. This leads to a drastic decrease in the average grain size from 30.46 μm to 0.75 μm (a reduction of 97.5%), achieving a remarkable columnar-to-equiaxed transition (CET). In terms of mechanical properties, the 3.0 wt.% TiH₂ addition group exhibits excellent plateau stress (28.5 MPa) and energy absorption capacity, which is mainly attributed to the synergistic effect of fine-grain strengthening and Orowan dispersion strengthening. Thermal tests reveal that the thermal conductivity of the 3.0 wt.% group reaches 123 W/(m·K) at 100 °C. The healing of cracks reconstructs the macroscopic heat conduction paths, resulting in a significant improvement in thermal conductivity compared with the unmodified group. This work provides a theoretical reference for the development of high-performance, crack-free, and multi-functional integrated aluminum alloy components via additive manufacturing. Full article

Environmental economics and policy research has paid limited attention to interfirm spillover effects on firm-level performance. This study addresses this gap by distinguishing between the direct and spillover effects of environmental regulation and firm-specific resources on firm performance. Using panel data for Korean manufacturing firms, we estimate a dynamic spatial Durbin model (SDM) that accounts for both temporal persistence and spatial dependence. The empirical results provide clear evidence. First, environmental regulation and firm-specific factors—including intellectual capital, physical capital, and organizational slack—exert statistically significant positive direct effects on firms’ sustainable growth rate (SGR). Second, interaction effects are crucial: environmental regulation significantly enhances SGR when combined with organizational slack, highlighting the importance of internal resource conditions. Third, spatial spillover effects are identified only under specific configurations. Environmental regulation generates positive spillover effects when interacting jointly with intellectual capital, physical capital, and organizational slack, rather than as an independent driver. Similarly, physical capital produces spillover effects through its interactions with other firm resources. Importantly, these effects vary across firms. Spillover effects are more pronounced in firms with high absorptive capacity, whereas they are weaker or insignificant in firms with low absorptive capacity. Overall, the findings indicate that environmental regulation affects firm performance primarily through resource complementarities and conditional spatial interactions, offering policy implications for more targeted regulatory design Full article

Against the backdrop of global energy landscape restructuring, the advancement of the “dual-carbon” goals, and escalating external uncertainties, coal, as the “ballast stone” of China’s new energy system, faces new challenges in terms of supply chain stability and security. Therefore, scientifically assessing China’s coal supply chain resilience (CSCR) is of significant theoretical and practical importance for systematically identifying its supply vulnerabilities and ensuring energy supply security under extreme conditions. In the paper, we construct a composite evaluation indicator system using national statistical data from 2010 to 2024. We operationalize resilience across the following four capacities: resistance, absorption, recovery, and adaptive capacity. Annual resilience levels are measured using an integrated framework. This framework combines an improved entropy weight method, TOPSIS, and gray relational analysis (GRA). We then use the indicator contribution degree and obstacle degree models to identify the most influential factors. The results indicate that China’s CSCR followed a fluctuating upward, W-shaped trajectory during 2010–2024, with a marked acceleration after 2020. Resistance and absorption capacities display pronounced volatility. Recovery and adaptation capacities improve steadily. The dominant obstacle factors include the share of intelligent coal production capacity, labor productivity per employee, the scale of workforce security, and the working-capital turnover ratio. These findings provide empirical evidence and policy-relevant insights for strengthening China’s CSCR and reinforcing national energy security. Full article

Artificial composite stones have recently attracted attention as multifunctional materials for construction and defense-related applications. In this study, a novel composite stone was developed using waste limestone as the primary mineral filler, combined with an unsaturated polyester resin matrix and reinforced with glass powder and chopped glass fibers. The influence of binder content and reinforcement type on physico-mechanical and microstructural behavior was investigated. Experimental characterization included water absorption, compressive strength, abrasion resistance, acid resistance, and optical microscopy. The results demonstrated that fine fillers improved matrix densification and reduced porosity, while short glass fiber reinforcement enhanced load-bearing capacity. Abrasion resistance and durability were found to depend on binder content and particle packing characteristics. Overall, the developed composite material exhibits promising mechanical performance, low water absorption, and improved durability, suggesting its potential as a candidate material for applications requiring environmental resistance, including potential use in defense-related camouflage applications. Full article

The need for reliable preventive medicine tools is growing, especially for diseases with long diagnostic delays, such as endometriosis, which can take several years to diagnose. In this context, cellulose acetate nanofibrous membranes were prepared via electrospinning, to create the absorbent core of a smart wearable in the form of a sanitary pad, intended to support electronic diagnostic devices. A multi-layered structure was opted for, with each layer acting in a specific way according to its position within the pad, regarding mainly absorbency and porosity. The membranes were ultralight and highly absorbent, with single membranes showing an absorbency of 20–70 times their initial weight, and multi-layered membranes 15–30 times. Morphological evaluation of the pad was used as the basis for the optimization of the fabrication parameters, while liquid absorption capacity confirmed the pad’s high absorbency. Additionally, chemical and toxicological assessments indicated in vitro biocompatibility of the pad. The potential of the electrospinning process in the fabrication of menstrual hygiene pads is shown by these results. Future studies should focus on the integration of smart devices within the pad, as well as their functionality and effectiveness. Full article