Search Results (20,406)

Soil organic carbon (SOC) in mountain forest ecosystems exerts critical controls over regional carbon balance and climate feedback loops. This study collected 209 stratified topsoil (0–30 cm) samples across temperate mountain forests of Northeast China, conducted a boosted regression tree (BRT) modeling framework integrated with space-for-time substitution, and established 15 combined thermopluviometric sensitivity scenarios to simulate SOC shifts under diversified climate disturbances. Tenfold cross-validation yielded a model mean R² of 0.62, revealing mean annual temperature (MAT, RI = 35.31%) as the most influential predictor of SOC spatial variation, followed by elevation (ELE, RI = 19.11%), while single-season NDVI and soil particle fractions showed weak predictive capacity. Multi-scenario spatial simulation outputs demonstrated that simultaneous warming and aridification drastically reduce the coverage of high SOC zones, whereas increased precipitation can partially offset temperature-induced carbon mineralization losses. Terrain-mediated SOC spatial stratification remained stable across all climate backgrounds. This study quantifies the layered environmental association hierarchy of mountain SOC and generates spatially explicit modeled carbon sink projections under climate change. The terrain-dependent SOC response patterns provide operable differentiated carbon regulation guidance: humid low-lying convergence zones require long-term soil moisture conservation, while arid steep ridges need native mixed forest restoration to lift baseline carbon storage capacity, supporting precise watershed climate adaptation and targeted forest carbon sink management for temperate mountain regions. Full article

This work reports the synthesis of the organic–inorganic copper chloride perovskite (C₆H₅CH₂NH₃)₂[CuCl₄] and its application as an electrode material for lithium-ion batteries. Hybrid copper halide perovskites have emerged as environmentally friendly alternatives to lead-based systems due to their structural versatility and chemical stability; however, their electrochemical energy storage properties remain largely unexplored. To the best of our knowledge, this is the first report investigating (C₆H₅CH₂NH₃)₂[CuCl₄] as an electrode material for lithium-ion batteries. The structural and morphological characteristics of the material were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and infrared spectroscopy (IR), confirming the formation of a layered perovskite structure. Electrochemical performance was evaluated by cyclic voltammetry and galvanostatic charge–discharge measurements. The material delivered an initial specific capacity of 114 mAh g⁻¹ at a current density of 20 mA g⁻¹ and maintained a coulombic efficiency around 99% after 100 cycles, indicating good cycling stability. The electrochemical behavior suggests that the reversible redox activity of Cu species contributes significantly to the charge storage mechanism. Postmortem XRD analysis revealed that the original perovskite framework was only partially retained after cycling, as several characteristic diffraction peaks remained while others disappeared, indicating partial structural decomposition. These results highlight the potential of chlorocuprate-based hybrid perovskites as alternative electrode materials for lithium-ion batteries. Full article

The operating frequency of a resonant oscillator is determined by the coupled behavior of the resonator, sustaining electronics, package, power supply, mounting conditions, and operating environment. Frequency stability is critical in sensor systems, where oscillators provide references for sampling, synchronization, phase-sensitive measurements, sensor fusion, and distributed sensing. This review examines how these factors affect the short- and long-term stability of quartz oscillators (XOs, TCXOs, and OCXOs) and microelectromechanical systems (MEMS) oscillators. Organized by physical cause rather than device type, the review covers temperature, including gradients and hysteresis, aging, acceleration, vibration, shock, pressure, humidity, power-supply and load variations, electric and magnetic fields, electromagnetic interference, and ionizing radiation. For each factor, the dominant degradation mechanisms and compensation methods are compared across both technologies. The comparison indicates that OCXOs retain an advantage in low-noise timekeeping over long averaging times, whereas advanced MEMS oscillators can approach quartz performance in selected operating regimes while offering smaller size, monolithic integration, and, in ruggedized products, 0.01 ppb/g acceleration sensitivity and 20,000 g shock ratings. In the literature reviewed, appropriate measurement methods exist but are applied inconsistently across technologies. Oscillator selection should therefore be based on a comprehensive error budget covering all relevant environmental and system-level factors. Full article

Microplastic pollution severely threatens aquatic ecosystems, yet the trophic microecological risks of petroleum-based polyvinyl chloride (PVC) and biodegradable polyhydroxyalkanoate (PHA) microplastics remain insufficiently compared. This study established a two-trophic food chain model with Daphnia magna and zebrafish to explore the toxic effects and microbial disturbances of environmentally relevant 0.1 mg/L PVC and PHA. A 21-day chronic exposure induced no physiological damage to the survival, growth, reproduction, and locomotion of both organisms, suggesting conventional phenotypic indicators fail to identify early microplastic stress. However, trophic microplastic exposure triggered prominent zebrafish gut dysbiosis with distinct pathogen enrichment patterns. PHA trophic exposure enriched plant pathogenic genera (Acidovorax, Clavibacter, Rhizobium), whereas PVC trophic exposure accumulated zoonotic and clinical pathogens (Acinetobacter, Neisseria, Mycobacterium, Aeromonas). This work verifies that PHA is not entirely eco-safe, and PVC poses greater ecotoxicological risks via trophic pathogen transmission, providing genus-level evidence for differentiated microplastics risk assessment. Full article

The increasing adoption of additive manufacturing in the construction sector has intensified the demand for lightweight, recyclable cement-based composites with low environmental impact, suitable for automated 3D printing. Foamed concrete reinforced with dispersed fibers and incorporating recycled constituents represents a promising class of multifunctional materials. However, its environmental performance remains insufficiently characterized. This study provides a comprehensive evaluation of thermal stability, leaching behavior, and microbial resistance of 3D-printable fiber-reinforced foamed cement composites produced with recycled components. Thermogravimetric–Fourier transform infrared (TG–FTIR) analysis confirmed a characteristic three-stage thermal decomposition pathway typical of hydrated cementitious systems. All composites exhibited high thermal stability, with residual masses of 88.56–90.17% at 900 °C. The binder type exerted a stronger influence on decomposition behavior than atmospheric exposure or freeze–thaw conditioning. Leaching tests revealed strongly alkaline eluates (pH 11.0–11.4), low total organic carbon (<0.6 wt.%), and only trace concentrations of BTEX (35–41 μg/kg), PAHs, and PCBs. Alkali activation increased the release of chromium (3.6–4.0 mg/kg), arsenic (1.2 mg/kg), copper (4.5 mg/kg), antimony (0.26 mg/kg), and sulfates (2700–4700 mg/kg), accompanied by elevated total dissolved solids (~18,000 mg/kg). Nevertheless, all environmentally relevant constituents remained well below the waste acceptance criteria (WAC), confirming effective immobilization of hazardous species within the hardened matrix. The results provide new insights into the relationships among material composition, porous microstructure, and environmental safety, demonstrating that the developed 3D-printable foamed composites exhibit robust performance, suitability for safe and durable applications, and favorable environmental performance. Full article

The withdrawal of antibiotic growth promoters has fundamentally changed the priorities of poultry nutrition, shifting attention from growth promotion towards maintenance of intestinal homeostasis and physiological resilience, defined here as the capacity of the organism to maintain or restore functional homeostasis when exposed to biological, nutritional, or environmental challenges. Although plant-derived feed additives have attracted considerable interest as natural alternatives, their biological activity is still commonly interpreted as a collection of independent antimicrobial, antioxidant, or immunomodulatory effects. This fragmented perspective may not fully capture the interconnected and context-dependent nature of their effects across experimental models. This review develops an integrated conceptual framework in which phytogenic feed additives are considered as potential systems-level modulators of the microbiota–gut–immune axis rather than as isolated sources of bioactive compounds. We synthesise experimental evidence from 155 broiler chickens identified through searches of PubMed, Web of Science, Scopus, and Google Scholar from database inception to June 2026, covering microbial ecology, intestinal morphology and barrier function, microbial metabolites, redox balance, inflammatory signalling, and innate and adaptive immunity across infectious, nutritional, and environmental challenge models. Particular attention is given to the different levels of evidence provided by culture-based and targeted analyses, microbiome profiling, integrated host–microbiome studies, and multi-omics approaches. The available evidence suggests that structurally diverse phytochemicals can influence overlapping regulatory networks linking microbial ecology, epithelial barrier integrity, redox balance, inflammatory signalling, and immune function. However, the magnitude and direction of these responses vary substantially according to botanical source, phytochemical composition, dose, formulation, duration of supplementation, animal genotype, basal diet, and experimental challenge. Collectively, the available evidence supports a paradigm shift from compound-centred interpretation towards network-based regulation of host homeostasis. Within this context, physiological resilience refers to the capacity to maintain or restore functional homeostasis in response to biological, nutritional, or environmental challenges. It may emerge from coordinated interactions among the intestinal microbiota, the epithelial barrier, and the immune system. Phytogenic supplementation may contribute to resilience by simultaneously modulating several components of this network, although causal relationships remain incompletely established for many proposed mechanisms. This systems-level perspective provides a framework for integrating heterogeneous evidence and for identifying priorities for future research, including dose–response relationships, phytochemical combinations, longitudinal multi-omics approaches, and validation under commercially relevant production conditions, with implications for precision poultry nutrition. Full article

Chemical pollution from industrial, agricultural, and urban activities represents a major threat to freshwater ecosystems and aquatic organisms. This study evaluated hepatic biomarker responses in Oreochromis niloticus (Nile tilapia) maintained under chronic environmental exposure to water from the Iguaçu River, one of the most polluted urban rivers in Brazil. Juvenile fish were kept in cages at three sites along the river, and hepatic biomarkers were assessed after 15 and 22 months of environmental exposure. Fish showed severe histopathological liver lesions, activation of antioxidant defenses, and oxidative stress responses accompanied by increased DNA damage. Immunological responses, particularly melanomacrophage proliferation and granuloma formation, were also observed across the monitored exposure scenarios. Alterations in plasma biochemical parameters, including AST, ALT, LDH, albumin, and globulin, were consistent with changes in hepatic function. Overall, the integrated biomarker responses revealed distinct patterns of biological alteration among the monitored exposure scenarios and were consistent with chronic exposure to complex environmental contaminant mixtures. These findings are consistent with alterations in liver integrity in fish maintained under long-term environmental exposure in the Iguaçu River. The study highlights the sensitivity of Nile tilapia as a bioindicator species for aquatic biomonitoring and provides valuable information to support environmental monitoring, risk assessment, and conservation strategies for the Iguaçu River Basin. Full article

Large yellow croaker (Larimichthys crocea) is an economically important marine fish species in China, yet regional variation in its gut microbial community structure and functional characteristics remains insufficiently understood. This study aimed to characterize and compare the gut microbiota of farmed large yellow croaker across five representative aquaculture regions. Intestinal microbial communities were characterized using 16S rRNA gene sequencing, followed by analyses of microbial diversity, taxonomic composition, predicted bacterial phenotypes, co-occurrence networks, and environmental associations. The five cultured populations shared a broadly similar microbial community structure dominated by Proteobacteria, Bacteroidota, and Firmicutes, whereas the relative abundance of several dominant taxa varied among regions. Alpha-diversity differences were mainly associated with community evenness and dominance rather than estimated richness. Although regional samples partially overlapped in ordination analyses, the aquaculture region explained 41.4% of the variation in gut microbial composition, indicating significant region-associated differentiation. Predicted microbial characteristics were comparatively similar among cultured populations, despite variation in taxonomic composition, while microbial network organization also differed across regions. Environmental variables showed clearer associations with water microbiota than with gut microbiota, and local aquaculture water represented a detectable but limited potential source of intestinal microorganisms. Overall, farmed large yellow croaker maintained a shared gut microbial community structure but exhibited region-associated variation in community composition and predicted bacterial phenotypes. These findings provide a regional baseline for understanding gut microbial variation in farmed large yellow croaker under different aquaculture conditions. Full article

River sediments act not only as important sinks for heavy metal pollution in watersheds, but also as potential secondary sources under changing environmental conditions. Heavy metals can enter river systems through industrial wastewater discharge, agricultural non-point runoff, urban stormwater and sewage inputs, mining and smelting activities, and atmospheric deposition. During adsorption onto suspended particles, sedimentation, and resuspension, metals such as Cd, Pb, Cr, Cu, Zn, Ni, As, and Hg progressively accumulate in sediments. Because heavy metals are persistent, non-degradable, and bioaccumulative, contaminated sediments can record historical watershed pollution while also releasing metals back into overlying water under hydrodynamic disturbance, pH and redox fluctuations, organic matter mineralization, benthic bioturbation, and dredging activities, thereby threatening aquatic ecosystem stability and human health. Using a global methodological framework with particular emphasis on Chinese river basins, this review systematically summarizes key issues in the study of heavy metal pollution in river sediments, including spatial–temporal distribution and operationally defined fractionation, pollution levels and ecological risk assessment, source apportionment, and remediation and management technologies. Current evidence indicates that heavy metal contamination in river sediments exhibits pronounced spatial heterogeneity and watershed-specific characteristics. Its distribution is jointly controlled by geological background, land use patterns, source input intensity, hydrodynamic conditions, sediment particle size composition, and organic matter content. Methodologically, the field has evolved from single total concentration monitoring and exceedance-based evaluation toward integrated assessment systems that combine total concentrations, operationally defined fractionation, bioavailability, ecological risk, health risk, and source contribution. The joint use of BCR sequential extraction, the geoaccumulation index (Igeo), the pollution load index (PLI), the potential ecological risk index (RI), the risk assessment code (RAC), sediment quality guidelines (SQGs), receptor models, isotope tracing, and machine learning has substantially improved pollution identification, risk zoning, and source apportionment. Overall, research on heavy metal pollution in river sediments has shifted from descriptive judgments of whether contamination exists toward mechanistic and management-oriented questions concerning pollution sources, risk evolution, and remediation strategies. However, important gaps remain in compound pollution transformation mechanisms, regional background values and evaluation benchmarks, uncertainty in model parameters, long-term dynamic monitoring, and engineering-scale verification of remediation technologies. Future studies should strengthen multi-media, multi-scale, and long-term monitoring and further integrate fractionation analysis, toxicological effects, source apportionment models, and remediation technologies to provide a scientific basis for watershed ecological security and precision management of contaminated sediments. Full article

Asphalt pavements suffer from progressive deterioration during service life due to aging, while conventional polymer modifiers raise environmental concerns regarding recyclability and volatile organic compound emissions. Functionalized-biochar derived from renewable biomass offers a sustainable alternative through its tunable surface chemistry and porous structure. This study develops and evaluates a nitrogen-rich, surface-functionalized biochar as a multifunctional asphalt binder modifier and elucidates the synergistic roles of inherent nitrogen and post-synthetic functionalization in governing binder performance. To this end, soybean powder was pyrolyzed to prepare the biochar precursor, which was subsequently characterized to determine its suitable pyrolysis temperature and surface properties. These analyses identified 300 °C as the preferable pyrolysis temperature within the tested range of 200–500 °C, maximizing biochar yield and achieving favorable surface physicochemical properties including the iodine adsorption value, oil absorption value, surface functional groups and pore morphology. To improve surface functionality, the biochar underwent a two-step modification: nitric acid oxidation followed by hydroxymethylation, hereinafter referred to as functionalized-biochar. The influence of functionalized-biochar content on asphalt binder performance was evaluated across dosages of 10–20 wt%, and 15 wt% was identified as the recommended content. Asphalt binder modified with 15 wt% functionalized-biochar exhibited improved high-temperature performance, as evidenced by enhanced rutting resistance factor G*/sin δ values obtained from dynamic shear rheometer testing. Aging resistance also improved, reflected in a lower complex modulus aging index and a higher phase angle aging index. At 15 wt% dosage, the softening point increased by 6 °C, and ductility rose by 10.6 cm relative to the base asphalt (1.9 cm), corresponding to a 557.9% improvement. Penetration declined by 17%, while the complex modulus aging index decreased from 3.44 to 1.68. Notably, the experimental program in this study was limited to binder-scale characterization. Full article

Agroforestry integrates environmental, climatic, productive, and socioeconomic dimensions. The position of rural livelihoods within its scientific structure remains still characterized. This study evaluated the temporal evolution, conceptual organization, domain representation, and geographical and economic distribution of global agroforestry research using 5711 Scopus-indexed journal articles published between 1979 and 2025. Scientific production increased markedly, with 4133 articles published during 2013 to 2025, accounting for 72.37% of the corpus. Thematic evolution showed a shift from early agronomic topics toward biodiversity, ecosystem services, carbon sequestration, and climate change. Multiple Correspondence Analysis of harmonized Author Keywords identified five clusters, with the first two dimensions explaining 39.76% of total inertia. Livelihood-related terms were embedded within the central agroforestry and sustainability cluster under the analytical configuration applied, and this pattern was maintained after excluding corpus-defining search-anchor terms. Production, silvopastoral, and agronomic management had the highest proportional contribution (57.92%), whereas environmental and biodiversity (43.88%), livelihoods and socioeconomic (43.81%), and climate, carbon and soil dimensions (42.50%) occurred at comparable proportions. Fractional affiliation analysis indicated that all domains occurred across regions and income groups, with livelihoods and socioeconomic research showing larger fractional contributions from Africa and lower-middle-income countries. Full article

Crustose coralline algae (CCA) are key reef-building organisms, yet their bleaching dynamics and associated environmental factors in natural ecosystems remain poorly understood. This is particularly relevant to Jeju Island, Korea, where declines in canopy-forming macroalgae and the expansion of CCA-dominated barren grounds are reshaping benthic communities, highlighting the need to monitor how CCA respond to environmental stress. In this study, bleaching dynamics were monitored monthly using Autonomous Reef Monitoring Structures (ARMS) deployed at Bomok, southern Jeju Island, Korea, during a 13-month period (August 2022–August 2023). Total CCA cover, bleached CCA cover, and bleached CCA ratio were quantified and compared with seawater temperature and daytime light intensity. Despite persistently high total CCA cover, the bleached CCA ratio varied markedly over time, with multiple peaks and subsequent declines, reaching a maximum of 65.8%. The bleached CCA ratio was positively correlated with daytime light intensity (ρ = 0.709, p = 0.015), whereas no significant association was detected with seawater temperature. Nine bleached specimens were assigned to the genus Porolithon based on psbA phylogenetic analysis, representing the first molecular identification of bleached CCA from Korea. These findings provide a temporal baseline for understanding CCA bleaching within the rapidly changing benthic communities of Jeju Island and indicate that light intensity may be an important environmental correlate of bleaching. Full article

Municipal sludge generation has increased rapidly with urbanization, creating significant challenges for sustainable waste management. This review proposes a system-oriented framework for sludge resource utilization by linking sludge characteristics, conversion technologies, environmental risks, and product applications. Major treatment pathways, including anaerobic digestion, pyrolysis, ozonation, and hydrothermal carbonization, are critically compared, with emphasis on their inherent trade-offs between resource recovery, energy consumption, and contaminant control. Particular attention is given to emerging contaminants, such as microplastics, per- and polyfluoroalkyl substances (PFAS), and antibiotic resistance genes, where the distinction between pollutant removal and actual risk reduction remains insufficiently addressed. The review highlights that no single technology can achieve optimal performance under all conditions, and integrated treatment trains are generally required for sustainable sludge management. Among these pathways, pyrolysis shows considerable potential for applications requiring enhanced contaminant control and value-added biochar production due to its ability to promote organic contaminant degradation, heavy metal immobilization, and carbon storage. However, the feasibility of pyrolysis and other technologies depends strongly on site-specific factors, including sludge properties, energy availability, economic conditions, and regulatory requirements. Future research should focus on integrated process optimization, comprehensive pollutant fate assessment, and standardized evaluation frameworks to advance sludge management toward a circular economy. Full article

Background/Objectives: Certain strains of Lactobacillus acidophilus are widely used as probiotics. However, their functional potential for female reproductive tract health remains insufficiently characterized. While most studies have focused on individual strains, the distribution of putative probiotic-associated genes across the species remains unclear. This study aimed to evaluate the vaginal probiotic potential of Lb. acidophilus using population genomic analysis and comparative phenotypic characterization. Methods: Pan-genomic analysis was performed on 109 Lb. acidophilus genomes (107 public genomes and 2 vaginal isolates). Putative probiotic-associated gene clusters were identified by functional annotation, categorized into functional modules, and compared among ecological-origin groups. Two vaginal isolates (strains A2 and A3) were characterized in vitro for growth under different pH conditions, cell surface hydrophobicity, lactic acid and hydrogen peroxide production, antimicrobial activity, hemolysis, and antimicrobial susceptibility. Results: The Lb. acidophilus pan-genome was closed, with 1782 of 1902 gene clusters (93.69%) classified as core. Thirty-six putative probiotic-associated gene clusters were identified and grouped into four modules: environmental tolerance, adhesion/colonization, exopolysaccharide/biofilm synthesis, and nutrient metabolism/microbial competition. Thirty-four of the 36 gene clusters were present in all 109 genomes, and no general ecological origin-specific distribution pattern was observed. Three bacteriocin-related gene clusters were conserved across all genomes. A2 and A3 exhibited similar lactic acid production and growth patterns at pH 4–6. Both produced relatively low amounts of hydrogen peroxide compared with the reference strains. A3 showed higher cell surface hydrophobicity and moderate inhibition against Gardnerella vaginalis, while A2 showed no inhibition of this organism. Both isolates were non-hemolytic, and were susceptible to vancomycin and linezolid, resistant to clindamycin, and non-susceptible to daptomycin. No acquired antibiotic resistance genes were detected. Conclusions: Most putative probiotic-associated gene clusters were conserved across the Lb. acidophilus population, whereas A2 and A3 showed strain-dependent phenotypic differences. These findings support combining population genomic analysis with strain-level phenotypic testing when selecting Lb. acidophilus candidates for bacterial vaginal infections. Full article

Reliable cropland, forestland, and grassland maps support resource assessment and ecological management in arid and semi-arid Central Asia. Existing land-cover products often delineate these classes differently, vary in reliability across classes and locations, and may share the same errors even when they agree. This study formulates multi-product fusion as a pixel- and class-specific reliability decision problem. To address this problem, we propose a reliability-adaptive fusion framework, the Discrepancy-Aware Reliability-Adaptive Fusion Network (DRAFNet), using 2020 maps from three global 30 m land-cover products—FROM-GLC Plus, GLC-FCS30D, and GlobeLand30—and variables representing aridity, temperature, precipitation, elevation, and slope. Unlike fixed-weight fusion methods and segmentation models that use the source products only as input channels, DRAFNet retains the categorical source decisions and adjusts each contribution according to its estimated reliability for the assigned class and location. Weight removed from an unreliable source is transferred to a residual expert, which provides an alternative prediction when the source products are unreliable or share the same error. Voting entropy and geo-environmental variables provide contextual information for this decision. On independent test samples from the five Central Asian countries, DRAFNet achieved an overall accuracy (OA) of 0.8275, a Kappa coefficient of 0.7698, a mean intersection over union (mIoU) of 0.7046, and a macro-averaged F1 score (Macro F1) of 0.8241. These values were 0.95–1.38 percentage points higher than those of U-Net++, the strongest benchmark. Local comparisons indicated more coherent spatial patterns and clearer boundaries in areas of pronounced disagreement. The mean and median absolute log-ratio deviations from area statistics reported by the Food and Agriculture Organization of the United Nations (FAO) were 0.618 and 0.450, respectively, both lower than those of the source products. These results support land-resource assessment and ecological management in Central Asia. Full article