Search Results (2,669)

Phosphorites are a vital source of phosphorus for agricultural and industrial applications and are increasingly recognized for their potential as secondary repositories of critical raw materials (CRMs) such as rare earth elements plus yttrium (REYs). This study investigates deep-sea phosphorites from the Galicia Bank, Madeira, and Canary Seamounts, in the NE Atlantic Ocean, which are spatially associated with ferromanganese (Fe-Mn) mineralization. Through integrated petrographic, geochemical, and in situ isotopic analyses (O and Sr), we assess the timing, processes, and paleoenvironmental conditions of phosphogenesis and its implications for CRM enrichment. Rare earth element patterns in apatite reflect a predominant seawater-derived signature with variable Ce anomalies. Nevertheless, variable Y/Ho ratios point to evolving fluid sources including a hydrogenous component (directly derived from seawater), modified porewaters and, locally, volcanic or possibly hydrothermal inputs. Oxygen and strontium isotope compositions constrain phosphogenesis to several episodes ranging from the Upper Cretaceous to the Middle Miocene, with distinct isotopic shifts identifying both primary formation and later overprinting processes mostly linked to Fe-Mn oxyhydroxide growth or volcanic–hydrothermal activity. These findings highlight the dynamic and multiphase nature of phosphorite formation in deep-marine settings. The integration of high-resolution geochemical and isotopic tools proves essential for reconstructing genetic histories, defining metallogenic context and evaluating CRM prospectivity in complex submarine systems. Full article

Dryland soils of the Caspian region of western Kazakhstan are exposed to environmental stress, including drought, alkalinity, low soil organic matter content, and anthropogenic pressure. In this preliminary study, bacterial communities were investigated in 18 soil samples collected from six sampling groups across Makat (M1, M2), Isatay (I1, I2), and Beyneu (B1, B2) districts. Soil physicochemical properties were measured, and bacterial diversity was analyzed using 16S rRNA gene sequencing of the V3–V4 region. Community composition analysis indicated spatial heterogeneity among the sampled groups. M1 and I1 showed the highest taxon richness, whereas B2 contained the highest number of unique taxa. Genus-level profiles showed that B1 and M2 were mainly associated with Rubrobacter and related actinobacterial taxa; B2 contained higher proportions of Marinobacter, Tychonema, Qipengyuania, and Halomonas; and I2 was enriched with Antarcticibacterium, Salinimicrobium, Rhodococcus, Gillisia, Marinobacter, Dietzia, and Pontibacter. Correlation analysis showed that several bacterial taxa were associated with soil organic matter content, total nitrogen, total phosphorus, exchangeable cations, and pH, although the overall Mantel relationship between soil properties and community structure was not significant. FAPROTAX-based prediction indicated differences in putative heterotrophic, nitrogen-related, sulfur-related, and hydrocarbon-associated functional categories among sites. Because FAPROTAX predictions are based on taxonomic composition, these results should be interpreted only as putative functional potential and not as evidence of actual microbial metabolic activity. These findings suggest that the sampled Caspian dryland soils contain distinct bacterial assemblages and taxa with potential ecological relevance; however, their role in dryland soil resilience or bioremediation should be verified through future culture-based, metagenomic, and functional validation studies. Full article

Impaired wound healing arises from interacting biological and material challenges, including persistent infection, biofilm formation, oxidative stress, unresolved inflammation, impaired angiogenesis, defective epithelialization, hemorrhage, and insufficient real-time assessment of wound status. Quantum dot (QD) and nanodot nanosystems have emerged as a versatile class of bioactive wound interfaces capable of addressing these barriers through functions that extend beyond passive coverage. This review synthesizes the design rationale, material composition, validation strategies, functional outcomes, mechanistic interpretation, and translational relevance of QD-enabled platforms for precision wound repair. Across the reviewed literature, carbon dots, graphene QDs, black phosphorus QDs, metal and metal oxide QDs, transition-metal nanodots, and hybrid nanocomposites were incorporated into hydrogels, films, sponges, nanofibers, microneedles, scaffolds, membranes, sprays, and injectable matrices. Their major precision-enabling attributes include localized antimicrobial and antibiofilm activity, redox-adaptive behavior, photothermal and photodynamic activation, inflammatory and macrophage modulation, hemostasis, controlled therapeutic delivery, angiogenic and epithelial support, and fluorescence-based monitoring. The strongest conceptual advance is the transition from static wound dressings toward adaptive biointerfaces that can sense, respond to, or compensate for local wound state abnormalities. Nevertheless, the field remains largely preclinical, with important gaps in long-term safety, standardized characterization, clinically predictive models, manufacturing reproducibility, regulatory alignment, and human validation. Future progress will depend on rationally simplified multifunctional platforms, rigorous comparative testing, wound state-specific evaluation frameworks, and translation-oriented safety and usability studies. QD nanosystems therefore represent a promising foundation for precision wound repair, provided that their multifunctionality is matched by equally rigorous evidence of safety, reproducibility, and clinical relevance. Full article

Surfactant-enhanced soil washing is a promising strategy for the remediation of organochlorine pesticide (OCPs) contaminated sites. In this study, we constructed a comprehensive evaluation framework integrating efficient parameter optimization, effluent recovery and ecological restoration assessment. Among the 14 evaluated washing agents, the non-ionic surfactant Triton X-100 exhibited superior solubilization capacity for highly hydrophobic OCPs. Under an optimal dosage of 2.0%, Triton X-100 achieved near-complete extraction of γ-chlordane and over 75% removal of mirex in both moderately and severely contaminated soils. Powdered activated carbon (PAC) demonstrated exceptional selective adsorption performance, significantly outperforming activated carbon fiber (ACF). The optimal PAC dosages (20 g/L) could extract over 90% of OCPs from the soil washing effluents, facilitating potential washing agent recycling. Furthermore, community-level physiological profiling (BIOLOG-AWCD) revealed distinct ecological trajectories post-washing. While nitrogen and phosphorus (N/P) bio-stimulation successfully restored and even surpassed the microbial diversity in moderately contaminated soils, it only partially alleviated the ecological vulnerability in severely contaminated soils (Simpson index < 0.45). These findings underscore that while surfactant-enhanced soil washing combined with selective adsorption constitutes a powerful physicochemical remediation cycle, restoring heavily degraded microhabitats necessitates an integrated approach coupling bio-stimulation with phytoremediation. Full article

Activated carbon is a commonly used catalyst and catalyst support. Its abundant surface groups play a key role in catalytic activity and selectivity, and therefore an in-depth investigation of the surface groups of activated carbon is of great significance. The surface groups of activated carbon are diverse and structurally complex, and the corresponding characterization methods are also varied, with each technique having its own advantages and limitations. This review systematically summarizes the sources, characteristics, and effects on catalytic processes of oxygen-containing, nitrogen-containing, phosphorus-containing, and other heteroatom-containing groups on activated carbon surfaces. Emphasis is placed on the application of Boehm titration, PZC/IEP, FT-IR, XPS, TPD-MS, Raman, XRD, solid-state NMR, SEM/EDS, and EPR/ESR in the study of surface groups on activated carbon. Because the formation and alteration of surface groups on activated carbon not only change the surface chemical properties of activated carbon but also affect its structure, charge, and related properties, a single characterization method cannot accurately and comprehensively reveal its characteristics. Therefore, in practical studies, multiple characterization methods should be combined for cross-validation from the perspectives of functional group type, chemical state, thermal stability, structural changes, and catalytic behavior, so as to establish reliable correlations among “group type–structural environment–catalytic performance” and provide a basis for the rational design and optimization of activated carbon catalysts. Full article

In the context of intensifying global climate change, high-altitude mountain ecosystems play a critical role in climate regulation, biodiversity conservation, and the advancement of sustainable human development. Plateau regions, such as the Qinghai–Tibet Plateau, are particularly sensitive and responsive to global climatic fluctuations and function as essential ecological barriers supporting development across Asia. These areas occupy a strategic position within Asia’s ecological security framework and the broader international community, influencing not only regional ecological stability and social cohesion but also sustainable development pathways. However, owing to their fragile ecosystem structures, limited regenerative capacity, and the ongoing expansion of urbanisation and human activities, these regions frequently suffer from habitat fragmentation and degradation of ecological functions. This issue is especially acute in natural protected areas adjacent to plateau cities. Consequently, there is an urgent need for quantitative assessments of ecological restoration effectiveness within natural protected areas, alongside investigations into development approaches that underpin long-term regional stability and sustainability. Focusing on Chokpori Mountain—the “urban green heart” of Lhasa, a principal city on the Qinghai–Tibet Plateau—this study develops a three-dimensional assessment framework encompassing ecological, economic, and social dimensions. By integrating the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model, remote sensing inversion techniques, field monitoring, and questionnaire surveys, the research systematically evaluates the effectiveness of ecological restoration and proposes insights for sustainable governance. The findings indicate that ecological restoration elicited positive ecological responses, evidenced by a 69.2% increase in soil retention post-renovation, an increase in vegetation coverage, and modeled total nitrogen (TN) and total phosphorus (TP) export loads demonstrating enhanced nutrient retention potential and improved water purification potential; (2) economic stimulation was evident, as demonstrated by an increase in average weekend daily visitor numbers from 876 to 1567 and a 24.2% rise in average monthly revenue of shops within a 1 km radius; and (3) social well-being improved, with ecological satisfaction reaching 89.2% and recognition of cultural communication attaining 67.3%. An integrated analysis indicates a synergistic enhancement of ecological environmental quality, regional vitality, and public perception. Accordingly, the outcomes of this study provide both theoretical insights and practical guidance for the ecological restoration and sustainable management of urban protected areas in high-altitude plateau regions worldwide. Full article

This study evaluated the association between vitamin D3 levels, transplanted kidney function, and body composition in 315 stable renal transplant recipients (median 7.7 years post-transplant). The biochemical profile included eGFR, PTH, calcium, phosphorus, and 25(OH)D₃ levels. Vitamin D status was defined as deficiency (<20 ng/mL), insufficiency (20–30 ng/mL), or optimal (>30 ng/mL). Body composition was assessed via bioelectrical impedance analysis, capturing parameters such as BMI, visceral fat area, and phase angle. Multivariable quantile regression models were used to assess the associations between clinical/metabolic parameters and graft function. Vitamin D3 supplementation was prescribed in 61.5% of patients, with 49.7% receiving active analogues and 50.3% cholecalciferol. Results showed that 25(OH)D₃ levels did not correlate with graft function in the total population, and no significant differences in eGFR were observed regarding vitamin D status. In multivariable models, 25(OH)D₃ levels correlated significantly only with calcium levels. No significant correlations were observed between vitamin D and transplant vintage, age, eGFR, or any anthropometric and body composition parameters. Full article

Soil biological activity integrates microbial processes involved in organic matter decomposition and nutrient cycling, yet its long-term response under agricultural systems in Paraguay remains poorly documented. This study evaluated soil biological activity in a 32-year field experiment in the Eastern Region of Paraguay, comparing cropping systems differing in tillage intensity and crop rotation diversification. Soil samples from the 0–20 cm layer were analyzed for microbial biomass carbon (MBC), β-glucosidase (BG), urease (URE), acid phosphatase (AP), arylsulfatase (ARS), soil organic carbon (SOC), total nitrogen (TN), available phosphorus (P), sulfur (S), and pH. Our results revealed that BG, URE, and AP increased under no-tillage, particularly in the most diversified no-tillage rotation, with 71%, 90%, and 51% higher activities, respectively, than conventional tillage. MBC and ARS were not significantly affected by cropping systems. Principal component analysis, Spearman correlations, and Mantel analysis indicated that enzymatic responses were associated with SOC, TN, P, S, and pH, linking soil biological activity with chemical attributes related to nutrient cycling. These findings show that diversified no-tillage strengthens soil biological functioning under representative Paraguayan grain-production conditions, providing long-term local evidence to guide soil-health management, crop diversification strategies, and more sustainable agricultural systems in the region. Full article

In resource-poor sandy habitats, alien plant co-invasion often triggers intense belowground competition mediated by rhizosphere microorganisms. However, the mechanisms by which these plants overcome nutrient limitations remain unclear. Here, we conducted an eight-month in situ monitoring of single- and co-invasion plots of Solanum rostratum and Cenchrus pauciflorus Benth. in the Horqin Sandy Land. By integrating soil enzyme assays with 16S rRNA and internal transcribed spacer (ITS) amplicon sequencing, we characterized their rhizosphere microbial community assembly. Co-invasion exposed both species to convergent biotic stress, characterized by the significant enrichment of the pathogenic fungi Didymella and Pseudogymnoascus (linear discriminant analysis (LDA) > 4.0). To mitigate these pressures, the dominant competitor, S. rostratum, specifically recruited a cross-kingdom phosphate-solubilizing consortium comprising Bacillus and Penicillium (LDA > 4.0). This targeted recruitment significantly enhanced rhizosphere activities, increasing phosphatase and sucrase to 86.10 U/g and 2.17 U/g, respectively, thereby maintaining available phosphorus at a high level (35.55 mg/kg). Conversely, the subordinate competitor, C. pauciflorus, lost key native stress-resistant bacteria such as Rubrobacter (relative abundance dropping from 5.39% to 3.27%) and failed to recruit effective microbes, leading to the rapid depletion of available phosphorus (dropping to 21.38 mg/kg). Ultimately, under dual nutrient and pathogenic stress, the precise recruitment and functional integration of cross-kingdom phosphate-solubilizing microbes are strongly linked to the divergent belowground competitive outcomes between these co-invading plants. Full article

This research reports on the properties of oxide-ceramic coatings produced by plasma electrolytic oxidation in novel electrolyte solutions for implantology applications. A series of bioactive calcium-phosphate coatings was synthesized on medical-grade Ti-13Zr-13Nb alloy using the plasma electrolytic oxidation (PEO) method. Novel electrolytes enriched with calcium and phosphorus were developed, enabling the formation of coatings with tailored physicochemical and structural characteristics. A correlation was established between the electrolyte composition and the phase composition, thickness, morphology, porosity, and microhardness of the resulting coatings. The optimum coatings exhibited a Ca/P ratio close to that of natural human bone tissue, homogeneity, a well-developed porous surface topography, and controlled resorption behavior. For the first time, a mechanism of calcium-phosphate coating resorption in a biologically active environment has been proposed. It involves partial dissolution, the formation of apatite-like surface structures, and the subsequent controlled release of Ca and P ions. In vitro testing in simulated body fluid indicated the potential bioactivity of the synthesized coatings. The proposed calcium-phosphate coatings may be considered promising candidates for future implant surface modification. The results obtained are significant for the development of advanced orthopedic and dental implants, including those fabricated using additive manufacturing technologies. Full article

Forest stand composition can regulate soil nutrient cycling by altering aggregate formation, nutrient partitioning and microbial extracellular enzyme activity. Here, we examined pure Pinus tabuliformis forest (YS), pure Quercus acutissima forest (ML) and mixed coniferous–broadleaved forest (HJ) in the Ziwuling forest region of the Chinese Loess Plateau. Soil aggregate composition, soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP) and extracellular enzyme activities were quantified across different aggregate-size fractions in the 0–100 cm soil profile. Except for the >5 mm aggregate fraction, the proportions of all other aggregate-size classes followed the order ML > HJ > YS, with ML and HJ showing increases of 19.94%–66.98% and 8.76%–35.01%, respectively, relative to YS. Mixed forest significantly promoted SOC content, with SOC contents 46.9% and 76.1% higher than those in YS and ML, respectively. In contrast, TN content was highest in YS and was 20.3% higher than that in HJ, whereas TP showed only small differences among forest types. SOC and TN were mainly enriched in smaller aggregate fractions, accounting for 49.7%–79.1% and 44.7%–81.3% of their total stocks, respectively, while TP was preferentially associated with larger aggregates, accounting for 54.9%–82.1%. Compared with YS, HJ increased EG, LAP, NAG and ACP activities by 42.2%, 14.9%, 18.0% and 42.5%, respectively. Compared with ML, HJ also showed generally higher extracellular enzyme activities, indicating that mixed forest favored the enhancement of most enzyme-mediated nutrient acquisition processes. Overall, forest stand type regulated extracellular enzyme activity by reshaping soil aggregate composition and aggregate-associated nutrient distribution. These findings help improve our understanding of aggregate-associated nutrient cycling processes in restored forest soils on the Loess Plateau and may provide a reference for future comparative studies on restoration effects among different forest types. Full article

Passivation is a feasible approach for remediating heavy metal-contaminated soil. However, how passivation stability depends on material type, dosage, and plant cultivar remains unclear. Phosphate rock powder (PR) and bentonite (BN) were applied for passivation at three dosages, and the passivation activity was evaluated on high- and low-Cd-accumulating wheat cultivars. Phosphate rock powder (PR) and BN decreased the available Cd content in the soil by 11.52–26.65% and 11.08–35.00%, and in the wheat grains by 7.28–49.94% and 14.14–57.61%, respectively. PR₃ and BN₃ enhanced wheat yield by 12.77–21.31% and 12.23–18.67%, respectively. The passivation activity of both materials increased with increasing dosage. The optimal ranges for effective, stable Cd passivation were 0.29–0.61 and 3.85–8.46 t ha⁻¹ for PR and BN, respectively. Path analysis revealed that PR acts mainly through increases in soil available phosphorus and associated changes in Cd fractions, whereas BN acts primarily through the soil cation exchange capacity; grain Cd was chiefly associated with reactive Cd fractions. The different Cd accumulation capacities of wheat cultivars affected the passivation effects of PR and BN. The soil of Jimai22 showed significantly lower EXC-Cd and Carb-Cd and significantly higher FeMnOz-Cd than Zhoumai18. Moreover, soil pH was higher for Jimai22 than for Zhoumai18. These results suggest that combining the selection of suitable passivation materials, optimising the dosage and planting low-Cd-accumulating cultivars is an effective strategy for maintaining Cd passivation in weakly alkaline soils. Full article

Biological soil crusts (BSCs) play key roles in arid, semi-arid regions and ecological marginal habitats. This study focused on four types of sand-fixing plantations established in 1990 in alpine sandy land (Salix psammophila, SL; Caragana korshinskii, NT; Salix cheilophila, WL; Populus simonii, XYY). Soil samples were collected from bare sand, algae crusts, and moss crusts. Soil particle size distribution, physicochemical properties, and enzyme activity were determined. Then bacterial communities were analyzed using high-throughput (Illumina) sequencing and the correlations among these three factors were examined. The results showed that: (1) From bare sand to algae and moss crusts, the content of fine particles (clay + silt) gradually increased. (2) Soil water content (SWC), nutrients and enzyme activities increased progressively. (3) In the study area, the dominant bacterial phyla of BSCs included Pseudomonadota, Cyanobacteria, Actinobacteriota and Vibrionota. Principal Coordinates Analysis (PCoA) and Analysis of Similarities (ANOSIM) results showed that BSCs drive the differentiation of bacterial communities during succession, while forest stands influence their spatial distribution. (4) Spearman’s correlation and redundancy analysis (RDA) showed that available phosphorus (AP), alkaline hydrolyzable nitrogen (AN), soil organic matter (SOM), catalase (CAT), pH, soil water content (SWC), and alkaline phosphatase (ALP) are key physicochemical factors shaping the bacterial community structure of BSCs. Mantel’s test confirmed that these variables mediated BSCs’ bacterial community structure. This study elucidates the mechanisms underlying ecological restoration via BSCs and provides a theoretical basis for future restoration efforts in alpine sandy land. Full article

This study aimed to characterize the spatial patterns of soil nutrients and labile carbon in the 0–20 cm surface layer of a red-soil bench-terrace hillslope during the first year following cut-and-fill engineering. Soil nutrient redistribution is classically conceptualized as upslope depletion and downslope enrichment, yet whether this paradigm holds after bench terracing remains poorly documente d. On a granite-derived red-soil hillslope in Yudu County, Jiangxi Province, China, we established three replicated transects across four slope positions in May 2025, one year after cut-and-fill bench terracing combined with Camellia oleifera–Pinus massoniana mixed young-forest restoration. The 0–20 cm surface layer was sampled for pH, organic matter, total nitrogen, total phosphorus, water-soluble organic carbon, particulate organic carbon (POC), and mechanical composition. The results showed that organic matter, total nitrogen, and POC all peaked on the upper slope, with enrichment factors of 8.8×, 3.8×, and 5.1× relative to the hilltop, respectively; the slope base did not function as a nutrient sink. Texture displayed a monotonic downslope differentiation but decoupled from the nutrient gradient, and pH was significantly negatively correlated with organic matter and POC. The observed short-term post-restoration non-classical pattern is best interpreted as the spatially heterogeneous footprint of subsurface exposure and localized topsoil redistribution during cut-and-fill engineering, overlain by one year of incipient biological input, rather than the product of modified erosion–deposition dynamics. POC appears to be a particularly sensitive tracer of early biological activity under these short-term post-restoration conditions when superimposed on a depleted inverted-surface baseline, and the pronounced spatial heterogeneity implies that precision management based on high-resolution spatial diagnosis is warranted to address the substrate patchiness inherited from cut-and-fill operations. However, the temporal scope of this one-year baseline survey limits the inference of long-term indicator performance, and follow-up monitoring is needed to confirm whether POC retains this sensitivity as the surface layer matures. Full article

Chromium is an environmental pollutant with high toxicity and carcinogenicity. It can induce severe oxidative stress and DNA damage after entering the human body through the food chain. As a plant growth-promoting rhizobacterium (PGPR) with both heavy metal tolerance and plant growth-promoting properties, Klebsiella variicola has considerable potential for the remediation of chromium contamination. In this study, chicory served as the experimental plant to explore the mitigating impacts of K. variicola on stress induced by hexavalent chromium (Cr(VI)) at a concentration of 400 mg/kg. The results showed that chromium severely inhibited the growth of chicory. In contrast, K. variicola significantly reduced the soil chromium content. As the chromium content decreased, the activities of soil urease, sucrase, catalase, and alkaline phosphatase were restored, increasing by 32.60–53.69%. Accordingly, the contents of total phosphorus, available phosphorus, total nitrogen, available nitrogen, soil organic carbon, and available potassium also increased by 34.71–51.81%. In addition, K. variicola reversed the decline in microbial diversity induced by chromium stress, promoted the growth of beneficial bacteria such as Acidobacteriota and Chloroflexota, and enhanced the stability of soil ecosystem functions. Ultimately, the growth inhibition of chicory caused by chromium stress was alleviated, with fresh weight, root length, maximum leaf width, maximum leaf length, plant height, and stem diameter significantly increasing by 21.89–61.60%. This study enhances our comprehension of the various functions of PGPR when exposed to heavy metal stress, and provides support for the development of microbe–plant combined strategies in the remediation of chromium-contaminated soils. Full article