Search Results (3,660)

This work systematically investigates the optical behaviors of cesium lead bromide perovskite quantum dots (CsPbBr₃ PeQDs) functionalized with reduced graphene oxide (RGO) at varying reduction levels, and further explores their feasibility as emissive layers (EMLs) in quantum dot light-emitting diodes (QLEDs). Four batches of RGO with tunable reduction degrees were synthesized by adjusting the amounts of ammonia solution and hydrazine hydrate added, followed by the fabrication of RGO@CsPbBr₃ hybrids via an in situ hot-injection method. Experimental characterizations reveal that the photoluminescence quantum yield (PLQY) of the as-prepared RGO@CsPbBr₃ composites can be precisely modulated from 45% to 65% by tuning the reduction degree of RGO. Using the optimized RGO@CsPbBr₃ sample, multilayer QLEDs with the architecture of indium tin oxide (ITO)/PEDOT:PSS/Poly-TPD/TAPC/RGO@CsPbBr₃/TPBi/Al were fabricated. Electroluminescence (EL) measurements show that the optimized device exhibits a turn-on voltage of approximately 3 V and a characteristic emission peak at 513 nm. Compared with devices based solely on bare CsPbBr₃ PeQDs, the composite-based QLED displays a slight blue shift in emission wavelength and enhanced electroluminescence intensity, which is attributed to the localized surface plasmon resonance effect induced by the RGO nanosheets. This work presents a reliable strategy to optimize perovskite hybrid optics for light-emitting applications. Full article

Cadmium (Cd) and lead (Pb) contamination may alter common buckwheat (Fagopyrum esculentum Moench cv. ‘Korona’) physiology and composition. The objective was to determine whether common buckwheat maintains physiological performance under controlled Cd and Pb exposure while assessing metal transfer to harvested achenes. A 12-day in vitro phytotoxicity assay based on seed germination and root elongation and a six-week pot experiment were conducted. Cd had a stronger impact on in vitro seed germination and root growth than Pb. Under the highest metal treatments, soil concentrations reached 14,733.98 µg g⁻¹ DW for Cd and 5621.60 µg g⁻¹ DW for Pb; concentrations in leaves and achenes were substantially lower, although Cd transfer to the achenes remained relevant to food safety. Adult plants showed no consistent treatment-related changes in leaf water content, photosynthetic pigments, or F_v/F_m. Biochemical analyses detected treatment effects in proline, H₂O₂, SOD, CAT, and total phenolics. The treatment with 1000 mg L⁻¹ of Cd showed the highest leaf SOD activity and mature-achene total phenolic content. The largest observed compositional difference was the high lysine content under 5000 mg L⁻¹ of Cd in leaves and mature achenes, but this coincided with substantial Cd contamination and therefore cannot be interpreted as biofortification or a nutritional benefit. Overall, responses were non-monotonic and organ-specific, indicating substantial physiological adjustment during short-term exposure while confirming Cd transfer to mature achenes as a food-safety concern. Full article

The Mar Menor, Europe’s largest coastal lagoon, faces severe ecological deterioration driven by nutrient loading, limited water renewal, and persistent contamination linked to mining residues from the Cartagena–La Unión district. Lead (Pb) levels remain an indicator of potential contamination caused by runoff from nearby abandoned mining operations and subsequent accumulation in marine organisms. This one-year study monitored total dissolved lead across eight representative locations using a rapid, simple analytical procedure combining ionic liquid dispersive liquid–liquid microextraction (IL-DLLME) and electrothermal atomic absorption spectrometry (ETAAS). The IL-DLLME system, based on in situ formation of the ionic liquid and APDC complexation, enabled highly efficient preconcentration, allowing the determination of ultra-trace Pb levels using low-cost instrumentation, achieving detection limits unattainable with previous monitoring techniques. Measured Pb concentrations ranged from 0.325 to 0.765 µg L⁻¹, showing low temporal variability but marked spatial heterogeneity, with elevated values in confined or anthropogenically influenced areas. The one-way ANOVA test confirmed significant spatial differences (p < 0.001), indicating persistent localized inputs and limited dispersion. These results highlight the chronic influence of historical mining and demonstrate IL-DLLME-ETAAS as a sensitive, sustainable analytical alternative for ultra-trace metal monitoring. Continued surveillance is essential to evaluate ecological risks and guide restoration efforts. Full article

The present study assessed potentially toxic elements (PTEs) and microbial contamination in soil and groundwater around a municipal solid waste dumpsite in Zomba, Malawi. The potential ecological and health risks to communities were also examined. The results revealed that wet season groundwater had elevated total coliforms (20,900 CFU/100 mL), Escherichia coli (3300 CFU/100 mL), Staphylococcus aureus (2500 CFU/100 mL), and Vibrio cholerae (5900 CFU/100 mL), which were significantly higher than the permissible limits of the Malawi Standards. In water samples, PTEs, particularly cadmium (Cd; 0.011–0.08 mg/L) and chromium (Cr; 0.02–0.41 mg/L), were detected at concentrations of concern. In the soil samples, lead (Pb) concentrations ranged from 0.16 to 224.05 mg/kg, copper (Cu) concentrations ranged from 3.03 to 94.86 mg/kg, Cd concentrations varied between the BDL and 0.89 mg/kg, arsenic (As) ranged from BDL to 1.88 mg/kg, and the Cr varied between 0.07 and 0.91 mg/kg. Furthermore, the cancer risk (CR) assessment indicated that all sampling points had CR levels greater than 1 × 10⁻³ for adults, with 40% of the sampling points showing elevated CR levels for infants and children, highlighting the cancer risk from Cd exposure, especially among vulnerable populations. Full article

Heavy liquid metals such as liquid lead (Pb) are attractive heat transfer media for advanced energy applications, despite their corrosive nature. In the search for heat-resistant austenitic materials that are corrosion resistant to liquid Pb at high temperature, three new Fe24Ni15Cr3Al-based alumina-forming austenitic (AFA) steels with slightly varying compositions have been developed. The present study investigates the corrosion behavior of these AFA materials using static exposure tests to molten Pb containing 1 × 10⁻⁷ wt.% dissolved oxygen. The corrosion tests are performed at 500 °C, 600 °C, and 700 °C for 1000 h, 2000 h, and 5000 h each. In addition to the variation in material, temperature, and exposure time, two different surface finishes are also used for the tests. Examination of the specimens after exposure shows the formation of oxide scales for temperatures up to 600 °C on all three AFA materials, with minor material-specific variations. Furthermore, the scale characteristics depend on the surface finish. Coarse ground surfaces exhibit thin Al-rich protective oxide scales, while fine ground surfaces show the formation of thick multilayer oxide scales susceptible to Ni dissolution and Pb penetration. Pb exposure at 700 °C leads to a severe corrosion attack of all three Fe24Ni15Cr3Al-based AFA steels. Full article

Trace element contamination in Amazonian freshwater ecosystems threatens riverine food security. This study evaluated two post-harvest treatments—ethylenediaminetetraacetic acid (EDTA) and Lactobacillus fermentum—to assess cadmium (Cd) and lead (Pb) variations in edible muscle of four Amazonian fish species (Cichla monoculus, Pimelodus jivaro, Platynematichthys notatus, and Serrasalmus rhombeus). Concentrations were determined using ICP-OES. Platynematichthys notatus exhibited the highest baseline bioaccumulation, whereas C. monoculus showed the lowest. Although main treatment effects should be considered exploratory, distinct species-dependent trends emerged. EDTA achieved the highest Cd reduction in P. notatus (49.78%), while L. fermentum demonstrated notable Cd and Pb reductions in C. monoculus, P. notatus, and S. rhombeus. Conversely, relative concentration increases occurred in P. jivaro under both treatments, reflecting matrix-related effects. These findings suggest that post-harvest efficiency depends on fish species and metal type. Probiotic post-harvest processing represents a promising strategy for reducing dietary exposure to Cd and Pb in Amazonian fisheries, though optimizing operational parameters for community-level applications remains necessary. Full article

Background: Chronic exposure to cadmium (Cd), lead (Pb), and mercury (Hg) has been associated with hepatic inflammation and metabolic liver dysfunction in experimental and epidemiological studies. Experimental evidence indicates that these metals can disrupt redox homeostasis, impair mitochondrial function, suppress nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent antioxidant responses, and activate inflammatory signaling pathways, with potential relevance to metabolic dysfunction-associated steatotic liver disease (MASLD) and hepatocellular carcinoma (HCC). Methods: PubMed/MEDLINE, Scopus, Web of Science, and the Cochrane Library were searched for peer-reviewed English-language literature published from January 2000 to March 2026. Epidemiological, experimental, and interventional studies linking Cd, Pb, or Hg exposure to hepatic outcomes, as well as potentially relevant plant-derived bioactive compounds, were considered. Results: Human studies report associations between metal exposure and hepatic outcomes, although the evidence is largely observational and affected by important confounders. Polyphenols, flavonoids, alkaloids, and terpenoids show antioxidant, anti-inflammatory, and metal-chelating effects predominantly in vitro and in animal models, with limited clinical validation. Conclusions: Current evidence supports the liver as a potentially important target of chronic metal exposure; however, the available human evidence remains largely observational and does not establish causality. The hepatoprotective effects of plant-derived compounds remain predominantly preclinical and require validation in human populations. Future longitudinal and interventional studies should incorporate exposure assessment and appropriate control of confounding before clinical or dietary recommendations can be established. Full article

The spatial distributions of the potential ecological risk index (RI) and the geoaccumulation index (Igeo) in soils of the Zhetysu region (Kazakhstan) were examined. The enrichment factor ranged from 39.4 for cadmium to 21,481 for nickel. There are few non-ferrous metal enterprises and mineral deposits located in the region. Soil sampling was conducted at 54 locations across the region. The contamination indices were calculated based on the concentrations of four heavy metals in the soil in 2025: copper (Cu), lead (Pb), cadmium (Cd), and nickel (Ni). The RI index varied across the study area within range of 53–353, with an average value of 129. The main points of high environmental risk are the Balkhash Lake’s eastern coast (RI = 318) and industrial city Tekeli (RI = 353). The Igeo values were as follows: Cu −0.61–3.82 (mean: 2.07); Pb −0.58–3.35 (mean: 0.49); Cd −2.91–2.15 (mean: −0.11); and Ni −4.23–4.17 (mean: 0.43). The transport of contaminants occurs under the influence of the wind regime and water erosion processes. Lead, cadmium, and nickel have a variation coefficient greater than 50, indicating metal particle transport from adjacent areas. Wind patterns in certain areas of the region determine the distribution of foci of high heavy-metal concentrations in the soil. Full article

Water-based perovskite solar cells (W-PSCs) provide a promising route toward reducing the use of hazardous organic solvents during perovskite fabrication. However, their development remains limited by sluggish precursor conversion, incomplete phase transformation, and poor control over film morphology. This review summarizes recent progress in W-PSCs, with particular emphasis on aqueous lead precursors and the subsequent conversion from precursor films to perovskite absorbers. The selection criteria for aqueous lead sources are first discussed in terms of water solubility, anion-Pb²⁺ interactions, precursor-solution stability, and ion-exchange behavior. Thermodynamic and kinetic considerations, including nucleation, crystal growth, reaction–diffusion coupling, and ion transport, are then discussed to provide a framework for understanding the conversion of aqueous precursor films into perovskites. Strategies for improving film formation are further classified into precursor-film and substrate engineering, conversion-process regulation, and ionic/compositional engineering. Particular attention is given to the role of precursor-film microstructure in regulating organic ammonium salt transport and conversion completeness. The photovoltaic performance of regular and inverted W-PSCs is subsequently compared, and the possible origins of their performance differences are discussed from the perspectives of precursor-film formation, perovskite conversion, film morphology, and interfacial properties. Finally, future opportunities in substrate-interface regulation, scalable aqueous processing, precursor and additive design, and life-cycle assessment are outlined. This review provides a reaction-diffusion-based perspective for understanding and improving water-based perovskite photovoltaics. Full article

Atmospheric particulate matter (PM) is a heterogeneous carrier of toxic metals whose environmental fate and biological effects depend on particle size, source-related composition, chemical form, solubility, and bioaccessibility. Lead (Pb), cadmium (Cd), and nickel (Ni) are of particular concern because atmospheric transport and deposition connect air pollution with persistent contamination of soils, vegetation, waters, sediments, food, and feed, followed by human and animal exposure. This review integrates evidence across a source-to-effect continuum encompassing emission, atmospheric transport, deposition, post-depositional redistribution, food-chain transfer, bioaccessibility, toxicokinetics, molecular toxicity, biomonitoring, remediation, and predictive assessment. Total PM mass and total metal concentration do not adequately represent biologically effective exposure, which is additionally determined by respiratory deposition, gastrointestinal release, dissolution kinetics, absorption, tissue distribution, intracellular retention, and interactions with co-associated constituents. Pb, Cd, and Ni share downstream effects including oxidative imbalance, inflammation, mitochondrial dysfunction, DNA damage, impaired genome maintenance, epigenetic remodeling, and cytogenetic abnormalities, but differ in environmental mobility, persistence, target-organ distribution, and molecular mechanisms. Effective risk assessment therefore requires coordinated multi-matrix monitoring, distinction between total and biologically accessible fractions, pathway-specific remediation, and appropriately validated predictive models. An integrated One Health framework can improve identification of priority matrices, exposure pathways, and risk-reduction measures. Full article

The design of a long-life reactor must not only achieve high burnup and closed fuel cycle utilization but also account for system heat transfer efficiency and inherent safety characteristics, thereby enhancing the long-term operational reliability of the reactor. To address these requirements, this paper proposes a long-life core design scheme based on spent-fuel plutonium-thorium nitride fuel and lead-bismuth eutectic coolant. This scheme exploits the excellent breeding and burnup performance of thorium-based fuel under a fast neutron spectrum and employs the neutronics calculation code DRAGON and the subchannel code COBRA-PB to carry out corresponding core physics analysis and safety characteristic assessment. The results show that the core can achieve a 25-year long refueling cycle, with mild reactivity swing over the entire lifetime and low control difficulty; the core radial power gradually shifts inward with increasing burnup, achieving power flattening and thereby mitigating safety risks caused by localized deep burnup; both the control assembly and shutdown assembly possess sufficient reactivity margins, with a single set of control mechanisms capable of achieving effective shutdown upon independent insertion; all key reactivity coefficients of the core are negative, demonstrating negative-feedback regulation capability and inherent safety characteristics. Calculations indicate that the cladding temperatures of both the average channel and the hottest channel remain within limits, leaving ample safety margins, ensuring long-term cladding mechanical integrity, and effectively preventing high-temperature nitride fuel from melting through the cladding, resulting in outstanding overall core safety performance. This core design scheme can provide a theoretical basis and design reference for the engineering application of long-life reactors. It should be noted that this study is an exploratory investigation at the conceptual design stage of the core. The analysis is conducted on the basis that the fuel supply remains stable, that steady-state calculation models are adopted, and that the performance data of key materials are taken from published literature. Accordingly, the conclusions drawn still require further support from experimental verification and detailed design. Nevertheless, the proposed core design can provide a theoretical basis and design reference for the engineering application of long-life reactors. Full article

Biodegradation of fused filament fabrication (FFF)-printed poly(lactic acid)/polyhydroxybutyrate (PLA/PHB) structures is governed by complex interactions between material composition, structural design, and degradation environment. Although these factors have been extensively investigated, they are typically evaluated independently, limiting a comprehensive understanding of their combined influence on degradation behaviour. This study synthesizes experimental evidence from a series of complementary studies on FFF-printed PLA/PHB systems to develop a transport-driven conceptual framework for interpreting biodegradation mechanisms. The integrated findings show that structural porosity increases fluid uptake (approximately 10% in dense structures versus 20% in porous structures) and promotes greater mass loss (25–40% after 45 days), while material modifications, including plasticizers and ceramic additives, influence local pH evolution and mechanical stability during degradation. The degradation response was also strongly dependent on the surrounding medium, with PBS maintaining relatively stable pH, saline and Hank’s solutions promoting acidification, and urea-based media leading to alkalization. Collectively, these observations indicate that fluid absorption and diffusion consistently mediate the interactions between material composition, scaffold architecture, and degradation environment, thereby governing the progression of biodegradation. Based on these experimentally supported relationships, a transport-driven conceptual framework is proposed to provide a unified qualitative interpretation of biodegradation in FFF-printed PLA/PHB structures. Rather than presenting new experimental data, this work offers an integrative perspective that may facilitate the interpretation of degradation behaviour, support the rational design of biodegradable scaffolds, and provide a foundation for future quantitative and predictive models. Full article

Under intensive urbanization, botanical gardens soils can serve as reference plots for urban areas, reflecting both natural (pedogenic) and anthropogenic factors of soil formation. In this context, historical and archeological information on the Botanical garden of Saint Petersburg State University (BG SPbU) is presented. For the first time, morphological, physicochemical, and ecotoxicological characteristics of the BG SPbU soils are assessed using full-profile soil pits. The ecological features of the BG SPbU are noted, and the specific structure of the upper soil layer (up to 2 m) is examined. The physicochemical properties of the BG SPbU soils are consistent with the optimal levels for green spaces of the highest (I) category. In the 0–90 cm layer of the studied soil pits, elevated concentrations (relative to Russian regulatory standards) of toxic trace elements (lead, zinc, arsenic) are found. No signs of vegetation stress were detected during the survey. At the same time, the measured concentrations of Pb, Zn, and As exceed the Russian MPC (maximum permissible concentrations) and APC (approximate permissible concentrations) for heavy metals. These exceedances provide important information for further monitoring and decision-making regarding urban pollution regulation, and contribute to the discussion on revising the MPC and APC values in line with international standards. The results can be used to optimize management practices for green spaces of the BG SPbU and can also be incorporated into the long-term urban environmental monitoring program initiated in Saint Petersburg in 1991. Full article

The Yinchuan Basin is situated at the leading edge of the latest northeastward expansion of the northeastern Tibetan Plateau. Sedimentary sequences at basin margins are crucial for understanding basin–mountain coupling relationships, yet systematic studies remain scarce. Here, we present a comprehensive sedimentological, paleomagnetic, whole-rock major and trace element, carbon–oxygen isotope, and detrital zircon U–Pb geochronological analysis of ZK01 Borehole (203 m) from the Kushui River area in the southern basin. Multi-proxy reconstruction reveals that Quaternary climate evolution can be divided into five stages: (1) Early Pleistocene (~2.58–1.77 Ma) alluvial fan-lacustrine alternations with high-amplitude climatic fluctuations, responding to orbitally-driven monsoon precipitation changes; (2) late Early Pleistocene (~1.77–0.78 Ma) stable lacustrine environment with sustained warm–humid conditions and subdued wet–dry oscillations; (3) Middle Pleistocene Climate Transition (MPT, ~0.9–0.6 Ma), marked by positive δ¹³C shifts, heavier δ¹⁸O values, and peak CIA values, indicating intensified chemical weathering in the catchment despite regional warming–drying; (4) Late Pleistocene (~0.16–0.12 Ma) extreme arid alluvial fan phase, with decreased CIA, recording a major dry event; and (5) post-last interglacial (~0.12 Ma–present) shallow lake recovery, with gradual enrichment of all proxies. Detrital zircon U–Pb age spectra show multi-peak characteristics (200–300 Ma, 400–500 Ma, etc.), consistent with upper Yellow River sediments. From the Late Pliocene to the Quaternary, the 200–300 Ma component increased while Precambrian components decreased. Provenance evolution indicates the Yellow River has been the primary sediment carrier, with increasing young components linked to the far-field effects of the Kunlun-Huanghe Movement, revealing tectonic uplift-driven headward erosion and provenance changes. We conclude that Quaternary environmental evolution of the Yinchuan Basin was jointly controlled by orbital-scale monsoon climate and episodic tectonic uplift of the northeastern Tibetan Plateau margin, with Yellow River integration further reshaping the basin’s drainage pattern. Full article

A^IVB^VI semiconductors, particularly lead chalcogenides, remain key materials for mid-wave infrared (MWIR) photodetection due to their narrow bandgap and exceptional carrier transport properties. However, the realization of high-quality p-type PbTe thin films, suitable for p–n junction devices, remains a technological challenge. In this work, we report the fabrication of high-mobility p-type PbTe thin films grown on muscovite mica by electron beam-assisted physical vapor deposition. The films were derived from a Te-rich Pb_0.999Te_1.001 ingot, enabling controlled acceptor formation via excess tellurium. Structural characterization reveals growth with strong (111) texture, large grain size, and low surface roughness. Comprehensive electrical measurements in the range of 80–300 K show a record room-temperature hole mobility of 876 cm²/V·s, achieved under optimized fabrication conditions. This figure approaches values typical for epitaxial n-type PbTe, indicating low scattering and high crystallinity. These results establish an effective route for producing strongly (111)-textured p-type PbTe films with high room-temperature hole mobility through optimized deposition and post-deposition annealing. Full article