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Under the "Double Carbon" target, the development of low-carbon agriculture requires a holistic comprehension of spatially and temporally explicit greenhouse gas (GHG) emissions associated with agricultural products. However, the lack of systematic evaluation at a fine scale presents considerable challenges in guiding localized strategies for mitigating GHG emissions from crop production. Here, we analyzed the county-level carbon footprint (CF) of China's rice production from 2007 to 2018 by coupling life cycle assessment and the DNDC model. Results revealed a significant annual increase of 74.3 kg CO2-eq ha-1 in the average farm-based CF (FCF), while it remained stable for the product-based CF (PCF). The CF exhibited considerable variations among counties, ranging from 2324 to 20,768 kg CO2-eq ha-1 for FCF and from 0.36 to 3.81 kg CO2-eq kg-1 for PCF in 2018. The spatiotemporal heterogeneities of FCF were predominantly influenced by field CH4 emissions, followed by diesel consumption and soil organic carbon sequestration. Scenario analysis elucidates that the national total GHG emissions from rice production could be significantly reduced through optimized irrigation (48.5%) and straw-based biogas production (18.0%). Moreover, integrating additional strategies (e.g., advanced crop management, optimized fertilization, and biodiesel application) could amplify the overall emission reduction to 76.7% while concurrently boosting the rice yield by 11.8%. Our county-level research provides valuable insights for the formulation of targeted GHG mitigation policies in rice production, thereby advancing the pursuit of carbon-neutral agricultural practices.
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Gases de Efeito Estufa , Oryza , Solo , Carbono , Dióxido de Carbono/análise , Agricultura/métodos , Gases de Efeito Estufa/análise , Pegada de Carbono , China , Óxido Nitroso/análiseRESUMO
The aggregation behavior of ubiquitous dissolved black carbon (DBC) largely affects the fate and transport of its own contaminants and the attached contaminants. However, the photoaging processes and resulting effects on its colloidal stability remain yet unknown. Herein, dissolved biochars (DBioCs) were extracted from common wheat straw biochar as a proxy for an anthropogenic DBC. The influences of UV radiation on their aggregation kinetics were systematically investigated under various water chemistries (pH, electrolytes, and protein). The environmental stability of the DBioCs before and after radiation was further verified in two natural water samples. Hamaker constants of pristine and photoaged DBioCs were derived according to Derjaguin-Landau-Verwey-Overbeek (DLVO) prediction, and its attenuation (3.19 ± 0.15 × 10-21 J to 1.55 ± 0.07 × 10-21 J after 7 days of radiation) was described with decay kinetic models. Pearson correlation analysis revealed that the surface properties and aggregation behaviors of DBioCs were significantly correlated with radiation time (p < 0.05), indicating its profound effects. Based on characterization and experimental results, we proposed a three-stage mechanism (contended by photodecarboxylation, photo-oxidation, and mineral exposure) that DBioCs might experience under UV radiation. These findings would provide an important reference for potential phototransformation processes and relevant behavioral changes that DBC may encounter.
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Raios Ultravioleta , Água/química , Carvão Vegetal/química , Cinética , Poluentes Químicos da Água/químicaRESUMO
The potential for species to shift their ranges to avoid extinction is contingent on the future availability and accessibility of habitats with analogous climates. To develop conservation strategies, many previous researchers used a single method that considered individual factors; a few combined 2 factors. Primarily, these studies focused on identifying climate refugia or climatically connected and spatially fixed areas, ignoring the range shifting process of animals. We quantified future habitat availability (based on species occurrence, climate data, land cover, and elevation) and accessibility (based on climate velocity) under climate change (4 scenarios) of migratory birds across the Yangtze River basin (YRB). Then, we assessed species' range-shift potential and identified conservation priority areas for migratory birds in the 2050s with a network analysis. Our results suggested that medium (i.e., 5-10 km/year) and high (i.e., ≥ 10 km/year) climate velocity would threaten 18.65% and 8.37% of stable habitat, respectively. Even with low (i.e., 0-5 km/year) climate velocity, 50.15% of climate-velocity-identified destinations were less available than their source habitats. Based on our integration of habitat availability and accessibility, we identified a few areas of critical importance for conservation, mainly in Sichuan and the middle to lower reaches of the YRB. Overall, we identified the differences between habitat availability and accessibility in capturing biological responses to climate change. More importantly, we accounted for the dynamic process of species' range shifts, which must be considered to identify conservation priority areas. Our method informs forecasting of climate-driven distribution shifts and conservation priorities.
Priorizar los esfuerzos de conservación en función de la disponibilidad y accesibilidad futura de hábitats ante el cambio climático Resumen El potencial de las especies para desplazar sus rangos y evitar la extinción depende de la disponibilidad y accesibilidad futura de hábitats con climas análogos. Para desarrollar estrategias de conservación, muchos investigadores anteriores utilizaron un solo método que consideraba factores individuales; algunos combinaron 2 factores. Principalmente, estos estudios se centraron en identificar refugios climáticos o áreas climáticamente conectadas y espacialmente fijas, ignorando el proceso de desplazamiento de rangos de los animales. Cuantificamos la disponibilidad futura de hábitats (basada en la presencia de especies, datos climáticos, cobertura terrestre y elevación) y la accesibilidad (basada en la velocidad climática) bajo el cambio climático (4 escenarios) de aves migratorias en la cuenca del río Yangtsé (YRB). Luego, evaluamos el potencial de desplazamiento de rangos de las especies e identificamos áreas prioritarias de conservación para las aves migratorias en la década de 2050 mediante un análisis de redes. Nuestros resultados sugieren que una velocidad climática media (es decir, 5−10 km/año) y alta (es decir, ≥ 10 km/año) amenazarían el 18.65% y el 8.37% del hábitat estable, respectivamente. Incluso con una velocidad climática baja (es decir, 0−5 km/año), el 50.15% de los destinos identificados por la velocidad climática eran menos disponibles que sus hábitats de origen. Basándonos en nuestra integración de la disponibilidad y accesibilidad de hábitats, identificamos algunas áreas de importancia crítica para la conservación, principalmente en Sichuan y en las partes media e inferior del YRB. En general, identificamos las diferencias entre la disponibilidad y accesibilidad de hábitats en la captura de respuestas biológicas al cambio climático. Más importante aún, tuvimos en cuenta el proceso dinámico de los desplazamientos de rangos de especies, lo cual debe considerarse para identificar áreas prioritarias de conservación. Nuestro método contribuye a la predicción de cambios en la distribución impulsados por el clima y las prioridades de conservación.
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The characterization of variations in riverine microbiota that stem from contaminant sources and transport modes is important for understanding biogeochemical processes. However, the association between complex anthropogenic nitrogen pollution and bacteria has not been extensively investigated owing to the difficulties faced while determining the distribution of nitrogen contaminants in watersheds. Here, we employed the Soil and Water Assessment Tool alongside microbiological analysis to explore microbial characteristics and their responses to complex nitrogen pollution patterns. Significant variations in microbial communities were observed in sub-basins with distinct land-water pollution transport modes. Point source-dominated areas (PSDAs) exhibited reduced microbial diversity, high number of denitrification groups, and increased nitrogen cycling compared with others. The negative relative deviations (-3.38) between the measured and simulated nitrate concentrations in PSDAs indicated that nitrate removal was more effective in PSDAs. Pollution sources were also closely associated with microbiota. Effluents from concentrated animal feeding operations were the primary factors relating to the microbiota compositions in PSDAs and balanced areas. In nonpoint source-dominated areas, contaminants from septic tanks become the most relevant sources to microbial community structures. Overall, this study expands our knowledge regarding microbial biogeochemistry in catchments and beyond by linking specific nitrogen pollution scenarios to microorganisms.
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Microbiota , Poluentes Químicos da Água , Animais , Nitrogênio/análise , Nitratos/análise , Monitoramento Ambiental , Poluentes Químicos da Água/análise , Água , Rios/químicaRESUMO
Comprehending the response of microbial communities in rivers along urbanization gradients to hydrologic characteristics and pollution sources is critical for effective watershed management. However, the effects of complex factors on riverine microbial communities remain poorly understood. Thus, we established a bacteria-based index of biotic integrity (Ba-IBI) to evaluate the microbial community heterogeneity of rivers along an urbanization gradient. To examine the response of Ba-IBI to multiple stressors, we employed a Bayesian network based on structural equation modeling (SEM-BN) and revealed the key control factors influencing Ba-IBI at different levels of urbanization. Our findings highlight that waterborne nutrients have the most significant direct impact on Ba-IBI (r = -0.563), with a particular emphasis on ammonia nitrogen, which emerged as the primary driver of microbial community heterogeneity in the Liuyang River basin. In addition, our study confirmed the substantial adverse effects of urbanization on river ecology, as urban land use had the greatest indirect effect on Ba-IBI (r = -0.460). Specifically, the discharge load from wastewater treatment plants (WWTP) was found to significantly negatively affect the Ba-IBI of the entire watershed. In the low urbanized watersheds, rice cultivation (RC) and concentrated animal feeding operations (CAFO) are key control factors, and an increase in their emissions can lead to a sharp decrease in Ba-IBI. In moderately urbanized watersheds, the Ba-IBI tended to decrease as the level of RC emissions increased, while in those with moderate RC emissions, an increase in point source emissions mitigated the negative impact of RC on Ba-IBI. In highly urbanized watersheds, Ba-IBI was not sensitive to changes in stressors. Overall, our study presents a novel approach by integrating Ba-IBI with multi-scenario analysis tools to assess the effects of multiple stressors on microbial communities in river sediments, providing valuable insights for more refined environmental decision-making.
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Microbiota , Urbanização , Teorema de Bayes , Bactérias , Monitoramento Ambiental , RiosRESUMO
BACKGROUND: Fungal keratitis is one of the major causes of visual impairment worldwide. However, the effectiveness of corneal collagen cross-linking (CXL) for fungal keratitis remains controversial. In this study, we developed an in vitro and an in vivo models to assess the efficacy of CXL for Fusarium keratitis. METHODS: The effect of in vitro CXL fungicidal was evaluated on the cultures of Fusarium solani which were exposed to irradiation for different durations. Viability of fungal was appraised under four conditions: no treatment (control); CXL: UVA (365 nm)/riboflavin; riboflavin and UVA (365 nm). Each batch of sterile plate culture was irradiated for different CXL durations. The in vivo Therapeutic effect was studied on a mouse keratitis model. The animals were divided randomly into three groups: group A with no treatment (control); Group B with CXL treatment for two minutes and group C with CXL treatment for three minutes. The CXL procedure was performed 24 h post inoculation in each group. All mice with corneal involvement were scored daily for 7 days and 10 days after infection. Corneals were extracted at various time points for quantitative fungal recovery. Histological evaluations were conducted to calculate the number of polymorphonuclear cells. RESULTS: Viability of fungal decreased significantly in CXL group with 30-min irradiation compared with that in control, riboflavin and UVA groups (P < 0.01). The colony-forming units (CFUs) of fungal solutions in culture significantly decreased with CXL treatment (P < 0.05). Clinical scores, corneal lesion, corneal opacity, neovascularization and the depth of ulceration scores in group B and group C were remarkably lower than that in group A (P < 0.05, P = 0.001, P = 0.001, P = 0.034 and P = 0.025 respectively). Scores of group C were much lower than that in group B. Histological revealed that destruction of corneal collagen fibers and infiltration of inflammatory cells into corneal tissue in group B and group C were much lower than that in group A. CONCLUSIONS: We believe that CXL treatment may be applied to fungal keratitis, therapeutic efficacy will improve with longer treatment duration.
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Anti-Infecciosos/uso terapêutico , Substância Própria/metabolismo , Úlcera da Córnea/tratamento farmacológico , Reagentes de Ligações Cruzadas , Infecções Oculares Fúngicas/tratamento farmacológico , Fusariose/tratamento farmacológico , Fusarium/efeitos dos fármacos , Animais , Colágeno/metabolismo , Contagem de Colônia Microbiana , Úlcera da Córnea/metabolismo , Úlcera da Córnea/microbiologia , Modelos Animais de Doenças , Infecções Oculares Fúngicas/metabolismo , Infecções Oculares Fúngicas/microbiologia , Fusariose/metabolismo , Fusariose/microbiologia , Fusarium/isolamento & purificação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fármacos Fotossensibilizantes/uso terapêutico , Riboflavina/uso terapêutico , Raios UltravioletaRESUMO
Tracking nitrogen pollution sources is crucial for the effective management of water quality; however, it is a challenging task due to the complex contaminative scenarios in the freshwater systems. The contaminative pattern variations can induce quick responses of aquatic microorganisms, making them sensitive indicators of pollution origins. In this study, the soil and water assessment tool, accompanied by a detailed pollution source database, was used to detect the main nitrogen pollution sources in each sub-basin of the Liuyang River watershed. Thus, each sub-basin was assigned to a known class according to SWAT outputs, including point source pollution-dominated area, crop cultivation pollution-dominated area, and the septic tank pollution-dominated area. Based on these outputs, the random forest (RF) model was developed to predict the main pollution sources from different river ecosystems using a series of input variable groups (e.g., natural macroscopic characteristics, river physicochemical properties, 16S rRNA microbial taxonomic composition, microbial metagenomic data containing taxonomic and functional information, and their combination). The accuracy and the Kappa coefficient were used as the performance metrics for the RF model. Compared with the prediction performance among all the input variable groups, the prediction performance of the RF model was significantly improved using metagenomic indices as inputs. Among the metagenomic data-based models, the combination of the taxonomic information with functional information of all the species achieved the highest accuracy (0.84) and increased median Kappa coefficient (0.70). Feature importance analysis was used to identify key features that could serve as indicators for sudden pollution accidents and contribute to the overall function of the river system. The bacteria Rhabdochromatium marinum, Frankia, Actinomycetia, and Competibacteraceae were the most important species, whose mean decrease Gini indices were 0.0023, 0.0021, 0.0019, and 0.0018, respectively, although their relative abundances ranged only from 0.0004 to 0.1 %. Among the top 30 important variables, functional variables constituted more than half, demonstrating the remarkable variation in the microbial functions among sites with distinct pollution sources and the key role of functionality in predicting pollution sources. Many functional indicators related to the metabolism of Mycobacterium tuberculosis, such as K24693, K25621, K16048, and K14952, emerged as significant important factors in distinguishing nitrogen pollution origins. With the shortage of pollution source data in developing regions, this suggested approach offers an economical, quick, and accurate solution to locate the origins of water nitrogen pollution using the metagenomic data of microbial communities.
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Microbiota , Poluentes Químicos da Água , Nitrogênio/análise , Rios/química , RNA Ribossômico 16S , Poluição da Água/análise , Monitoramento Ambiental , China , Poluentes Químicos da Água/análiseRESUMO
In order to reverse the trend of ecological deterioration and resolve the conflict between ecological conservation and economic development, it is necessary to evaluate the trends of ecosystem services (ESs) and unravel the relationship between ESs and environmental drivers and identify the priority areas for ESs. In this research, we used the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model to quantify the variation of four important ESs (water purification, water yield, soil conservation, and habitat quality) in the Dongting Lake Basin from 2000 to 2015. During the past 15 years, water yield was declined by 3.38% and soil conservation was increased by 1.45%. Water quality purification was deteriorated with the rise in phosphorus export (5.32%) and nitrogen export (4.09%). Meanwhile, habitat quality was decreased by 3.27%. Trade-offs occurred primarily among water yield and other ESs. Social-ecological drivers importance analysis found that water yield was primarily influenced by precipitation and temperature. By contrast, water purification and habitat quality were more affected by the distribution of land use and land cover (LULC). Soil conservation was closely related to precipitation and geographical factor. Based on the distribution of ESs and the intensity of human activities, we delineated priority areas for each ESs using the systematic conservation planning tool (Marxan). LULC shifted most dramatically in water yield reserves (6.49%) with a large amount of lands conversed to cropland (4.4%) and build-up land (0.27%), which further increased the risk of water scarcity, while LULC changed less in other ESs priority areas due to human activities. Our study helps develop conservation strategies within specific area cost-effectively and provides scientific support for future conservation program of ESs formulation and adjustment.
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Conservação dos Recursos Naturais , Ecossistema , Humanos , Qualidade da Água , Lagos , Solo , ChinaRESUMO
Natural inorganic colloids (NICs) are the most common and dominant existence in the ecosystem, with high concentration and wide variety. In spite of the low toxicity, they can alter activity and mobility of hazardous engineered nanoparticles (ENPs) through different interactions, which warrants the necessity to understand and predict the fate and transport of NICs in aquatic ecosystems. Here, this review summarized NICs properties and behaviors, interaction mechanisms and environmental factors at the first time. Various representative NICs and their physicochemical properties were introduced across the board. Then, the aggregation and sedimentation behaviors were discussed systematically, mainly concerning the heteroaggregation between NICs and ENPs. To speculate their fate and elucidate the corresponding mechanisms, the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) and extended DLVO (X-DLVO) theories were focused. Furthermore, a range of intrinsic and extrinsic factors was presented in different perspective. Last but not the least, this paper pointed out theoretical and analytical gaps in current researches, and put forward suggestions for further research, aiming to provide a more comprehensive and original perspective in the fields of natural occurring colloids.
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Ecossistema , Nanopartículas , Cinética , Nanopartículas/química , Coloides/químicaRESUMO
Although microplastics are emerging marine pollutants that have recently attracted increasing attention, it is still difficult to identify their sources. This study reviewed 6487 articles to determine current research trends and found 237 effective concentration points after sorting, which were distributed in four regions and related to freshwater ecosystems. Results found that 15 environmental variables represented natural and anthropogenic environmental characteristics, of which seven environmental variables were selected for experimental modelling. Random forest models fitted sample data, thus facilitating the identification of regional microplastics distribution. The global random forest model had random forest importance scores (RFISs) for gross domestic product, population, and the proportion of agricultural land use were 15.76 %, 15.64 %, and 14.74 %, respectively; these indicate that human activities significantly affected the global distribution of microplastics. In Asia, agriculture and urban activities are the main sources of microplastics, with an RFIS of 11.58 % and 12.24 % for the proportion of agricultural and urban land use, respectively. Activities in urban areas were determined to be the main influencing factors in North America, with an RFIS of 13.92 % for the proportion of urban land use. Agricultural activities were the main influencing factors in Europe, with RFISs for the proportion of agricultural land use of 16.90 %. Our results indicate that region-specific policies are required to control microplastics in different regions, with soil composition being a latency factor that affects microplastics' distribution.
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Microplásticos , Poluentes Químicos da Água , Humanos , Plásticos , Ecossistema , Efeitos Antropogênicos , Monitoramento Ambiental , Poluentes Químicos da Água/análise , Água DoceRESUMO
Antibiotics and microplastics (MPs) inevitably coexist in natural waters, but their combined effect on aquatic organisms is still ambiguous. This study investigated the individual and combined toxicity of chloramphenicol (CAP) and micro-polystyrene (mPS) particles to Microcystis aeruginosa by physiological biomarkers, related gene expression, and molecular dynamics simulation. The results indicated that both individual and joint treatments threatened algal growth, while combined toxicity was higher than the former. Photosynthetic pigments and gene expression were inhibited by single CAP and mPS exposure, but CAP dominated and aggravated photosynthetic toxicity in combined exposure. Additionally, mPS damaged cell membranes and induced oxidative stress, which might further facilitate the entry of CAP into cells during co-exposure. The synergistic effect of CAP and mPS might be explained by the common photosynthetic toxicity target of CAP and mPS as well as oxidative stress. Furthermore, the molecular dynamics simulation revealed that CAP altered conformations of photosynthetic assembly protein YCF48 and SOD enzyme, and competed for functional sites of SOD, thus disturbing photosynthesis and antioxidant systems. These findings provide useful insights into the combined toxicity mechanism of antibiotics and MPs as well as highlight the importance of co-pollutant toxicity in the aquatic environment.
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Cloranfenicol , Microcystis , Poliestirenos , Poluentes Químicos da Água , Antibacterianos/toxicidade , Cloranfenicol/toxicidade , Microcystis/efeitos dos fármacos , Microcystis/metabolismo , Microplásticos/toxicidade , Simulação de Dinâmica Molecular , Plásticos , Poliestirenos/toxicidade , Superóxido Dismutase/metabolismo , Poluentes Químicos da Água/toxicidadeRESUMO
The energy-absorption mechanism of nanofluidic systems is being investigated under dynamic cases, represented by the split Hopkinson pressure bar experiment. However, the cost of this cannot be ignored. Therefore, numerical simulation is playing an increasingly important role in optimizing the split Hopkinson pressure bar experimental technology and analyzing its accuracy. In this paper, a three-dimensional finite element simulation model of the split Hopkinson pressure bar experimental devices was proposed to analyze the energy-absorption capabilities of nanofluidic-system-filled tubes. The reliability of this methodology was discussed in terms of model construction, model validation and potential application, indicating the simulation methodology is applicable to further investigation and can provide a reference for engineering practice. The simulation results showed that the infiltration pressure and the mass ratio of solid to liquid determine the post-buckling compression stress and the effective compression stroke, respectively.
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Micro- and nano-plastics are common emerging pollutants of great interest. However, the impacts of them on terrestrial plants were still poorly understood. In this study, comparative effects of exposure of polystyrene nanoplastics (PS) and amino-modified polystyrene nanoplastics (PS-NH2) on Chinese cabbage (Brassica rapa L.) plants at different growth stages were investigated. Hydroponically cultured seedlings were exposed to PS and PS-NH2 at 0, 1, 10, and 100 mg/L at skotomorphogenesis stage for 48 h, photomorphogenesis stage for 18 h, and the whole stage, respectively. Results showed that both PS and PS-NH2 had no discernible effect on radicle elongation at the skotomorphogenesis stage whereas significantly (P < 0.05) reduced photosynthetic pigment contents in varying degrees (18.06%-28.52%, 22.46%-36.86%) at the photomorphogenesis stage and the whole stage. Moreover, there was no significant difference between PS treatments and control except the 26.52% decline of chlorophyll a content at 1 mg/L at photomorphogenesis, while PS-NH2 significantly (P < 0.05) decreased photosynthetic pigment contents except the chlorophyll b content at 10 mg/L at photomorphogenesis. The content of chlorophyll a decreased by 26.68% for the PS-NH2-treated group and 22.46% for the PS-treated group at 1 mg/L during the whole stage. Results manifested that less negatively charged PS-NH2 seemed to show more severe phytotoxicity both at the photomorphogenesis stage and the whole stage. Notably, the surface charge of nano-plastics and the integrity of seedling establishment could be the main factors impacting the above difference. These findings are expected to improve our understanding of the effects of PSNPs on crop plants.
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Brassica rapa , Poliestirenos , China , Clorofila A , Microplásticos , PlântulaRESUMO
Water scarcity and quality deterioration often occur in economically developing regions, particularly during crises related to climate change or increasing human activities. The assignment of priority areas is considered a suitable strategy for stakeholders to mitigate water crises and cope with water stress. However, most studies focused on protecting water bodies in priority areas and did not consider the hydrological/hydrochemical/hydroecological interaction between aquatic and terrestrial ecosystems. We divided a watershed into manageable areas to select priority areas for multiple water-related ecosystem services (WES-priority areas), considering the aquatic-terrestrial interactions to predict the effects of climate change and human activities. The proposed novelty framework couples the soil and water assessment tool and maximum entropy models with a systematic conservation planning tool. It uses the gross domestic product as the economic cost to assess dynamic changes and social-environmental driving forces. A case study is conducted in the Xiangjiang River basin, a modified watershed of the main tributary of the Yangtze River, China. Results revealed that most of the WES-priority areas were located in the southern and southeastern regions of the upper reaches in all climatic scenarios. The conservation efficiency of the WES-priority areas decreased from 1.264 to 0.867 in 50 years, indicating that the level of protection declined as climate change accelerated. The precipitation was positively correlated with the WES-priority area selection in all climate scenarios. The temperature was only negatively correlated with the WES-priority areas when it exceeded 20 °C, and this effect became more pronounced as the temperature increased. The topographic factors had the most crucial impacts on the upstream priority areas selection. The water flow regulation service played a leading role in identifying WES-priority areas in the middle reaches because the priority areas' distribution here was closely related to the water yield, and its proportion decreased with the acceleration of global warming. The number of WES-priority areas was relatively low in the lower reaches. It was positively associated with the gross domestic product and the amount of built-up land. The proposed framework for WES-priority areas identification enables a sound trade-off between environmental protection and economic development.
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Mudança Climática , Ecossistema , China , Conservação dos Recursos Naturais/métodos , Hidrologia , RiosRESUMO
Nanoplastics and carbon nanotubes (CNTs) is one of the emerging environmental contaminants and a widely used engineering nanomaterial, and their biological toxicity has been frequently studied. However, there has been no research on the combined exposure of these two totally different shape nanoparticles. To explore their potential threat to freshwater ecosystems, Microcystis aeruginosa (M. aeruginosa) was exposed to concentration gradients of polystyrene nanoplastics (Nano-PS) and multi-walled carbon nanotubes (MWCNTs). The physiological analysis and whole-transcriptome sequencing were integrated to certify the cytotoxicity. As the physiological results showed, the low concentration (5 mg/L) of these two nanoparticles showed a stimulation on the growth (6.49%-12.2%) and photosynthesis (0-7.6%), and the coexposure was slightly higher than individuals. However, other concentrations showed inhibitory effect, especially at high concentration (50 mg/L), and all physical signs and electron microscope images showed obvious cytotoxicity. Compared with the individuals, the coexposure showed an antagonistic effect induced by the heterogeneous agglomeration which decreased the surface toxicity and the contact with algae of nanomaterials. Transcriptome results showed that coexposure treatment had the fewest differential genes, and the primary effects embodied in the disturbances of cellular and metabolic processes which were superior to the individuals. In the 50 mg/L Nano-PS, the translation process was significantly disordered, and MWCNTs could disrupted the photosynthesis, multiple metabolism processes, membrane transport, and translation. These findings demonstrated the aquatic toxic mechanism from cellular and metabolic processes of Nano-PS and MWCNTs for M. aeruginosa and provided valuable data for environmental risk assessment of them.
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Microcystis , Nanotubos de Carbono , Ecossistema , Humanos , Microplásticos , Nanotubos de Carbono/toxicidadeRESUMO
Background: Immunologic graft rejection is the main complication of corneal transplants. This study aimed to investigate the effect of melatonin (MT) on the rejection of corneal transplantation. Methods: Corneal allografts were performed by grafting corneas from BALB/C mice to C57BL/6 hosts. MT (50 mg/kg) was intraperitoneally injected into the hosts every day from the day of transplantation. The survival of grafts was observed by slit lamp biomicroscopy, and inflammatory cell infiltration was detected by hematoxylin and eosin staining and immunohistochemistry. The balance of Teff and Treg immune cells in draining lymph nodes (DLNs) was detected by flow cytometry. The levels of cytokines related to the grafts and DLNs were detected using real-time fluorescence quantitative PCR. Additionally, we used the mouse macrophage line RAW264.7 to study the effect of MT on the activation of NLRP3 inflammatory body. Results: MT treatment improved the graft survival rate, reduced inflammatory cell infiltration in the graft, decreased the percentage of Th1/Th17 cells in the DLNs, and increased the percentage of Treg cells. Melatonin inhibited the activation of the NLRP3 inflammasome, thereby reducing the expression of IL-1ß and other related proinflammatory cytokines such as MCP-1, MIP-1, NLRP3, ASC, TNF-a and VEGF-A (all p < 0.05). Conclusion: Our study demonstrates that MT promotes the survival of mouse corneal grafts by inhibiting NLRP3-mediated immune regulation, reducing immune cell activation and cell migration, and inhibiting the production of inflammatory-related cytokines. Treatment with MT might provide a potential clinical therapeutic target for corneal transplantation.
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The primitive biochar (BC) and NiFe2O4/biochar composites (NFBC), biological adsorbents prepared from vinasse wastes, possess the environmental application in levofloxacin (LEV) removal. In this study, the efficient adsorption of LEV onto biochar synthesized by pyrolysis of vinasse wastes from aqueous environment was investigated. The influencing factors (i.e., pH, reaction time, and temperature) of adsorption process were also well studied. The results indicated that the maximum adsorption capacities of both BC and NFBC were occurred in mildly acidic condition (pH 6). In addition, the biochar adsorption capacities were obviously increased in higher temperature (25-45 °C). The chemistry adsorption and monolayer homogeneous dominated adsorption process of LEV onto BC and NFBC. The adsorption process was spontaneous and endothermic by thermodynamic analysis. The SEDA (site energy distribution analysis) explained that the adsorption effectivity increased by increasing site energy of biochar surface. The SEDA revealed the more energy heterogeneity in NFBC, fitting the characterization result of Fourier-transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The electron-donor-acceptor (EDA) interactions and hydrogen bonds is suggested as the major adsorption mechanism. And as for the adsorption of the various biowaste recycled synthetic, this study can be referred in discussion of performance analysis and optimal condition.
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Levofloxacino , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Compostos Férricos , Cinética , Compostos de Manganês , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
There is a growing recognition of the broader environmental significance of exploring the relative importance of climate change and anthropogenic impacts on hydrologic fluctuations in river-lake systems. In the case of Dongting Lake, the typical river-lake system, we collected the water level from 1990 to 2019, spanning before and after the operation of the Three Gorges Dam (TGD) in 2003. This study was conducted to detect water level fluctuations in Dongting Lake and to quantify the relative influence of climate, land cover and dam construction on water levels. We defined the impact of the dam construction as the three inlets inflow of Yangtze River (In-YR), and four waters inflow of Hunan (In-HN). The Mann-Kendall (M-K) test revealed the trends and change points of water level fluctuations. Structural Equation Model (SEM) was used to detect the direct and indirect effects of these factors on water level and quantify their relative importance. The MIKE21 hydrodynamic model reflected the spatial-temporal variability of water levels under the action of key driver. The results showed that the water level appeared a downward trend during 1990-2019 and the change point appeared in 2003; During 1990-2002, the significant factors were: precipitation (V = 0.469, P = 0.013), evaporation (V = -0.424, P = 0.029), non-agricultural cover (V = -0.334, P = 0.025), and agricultural cover (V = 0.235, P = 0.033); During 2003-2019, the significant factors were: In-YR (V = 0.436, P = 0.007), In-HN (V = 0.431, P = 0.012), and precipitation (V = 0.349, P = 0.045); The In-YR was the key factor affecting the changes of the water level during 1990-2019; Under the influence of In-YR, the most obvious fluctuation of water level was in the flood adjustment period (Jun-Aug) and the impoundment period (Sep-Nov) when the average declined by about 0.50 and 0.67 m, respectively. Our findings provide a new insight into how to better maintain the stability of river-water system water resources under the influence of multiple factors.
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Hydrology-climate changes and food availability are expected to be the primary drivers that result in a loss of waterbirds diversity. Non-biological factors are vital to food availability in interconnected river-lake systems, so in addition to identifying the ecological response to drivers, it is also important to analyze and quantify relationships between drivers. In order to explore the impacts of these drivers on the wintering waterbirds, we selected Dongting Lake (DTL) as a study area, which is a typical interconnected river-lake system in the middle and lower reaches of the Yangtze River Floodplain. The Anatidae species, most of which are herbivorous, were chosen as the representative waterfowl. The Pearson correlation coefficient was applied to select variables related to the timing of water recession and food availability, which have significant influences on the Anatidae. Then, the structural equation model (SEM) was carried out to quantify the relationships among the food availability, hydrological variables, and climatic variables. The results showed that unseasonably early or late water recession had a negative impact on the diversity of the Anatidae, and in particular affected population dynamics of the Lesser White-fronted goose Anser erythropus. Significant changes in Anatidae populations in DTL occurred in response to maximum NDVI (r = 0.53, p<0.01) and the interval time of water recession (r = -0.43, p<0.1). Water level, flow, and interval time of water recession explained 71% of maximum NDVI in DTL. In addition, hydraulic interactions between the mainstream and each lake jointly affected the inundation pattern and the vegetation growth stage of the lake after the flood season, thus affecting foraging suitability. Our findings suggest that water compensation should be carried out within an appropriate range of hydraulic gradient to optimize the time of water recession and improve the suitability of the habitat effectively.
RESUMO
PURPOSE: To compare the quality of life of senior first-year students with normal vision and myopia, and to explore the risk factors related to quality of life in students with myopia. METHODS: In this study, 1103 senior first-year students were enrolled in ten high schools. These students were divided according to the diopter degree, with 916 myopia students and 187 normal vision students. Visual function indexes, such as naked eye vision, were measured and recorded, and social demographic indexes and the National Eye Institute 25-Item Visual Function Questionnaire (NEI VFQ-25) was used. The differences in quality of life between the two groups were compared. Multiple linear regression analysis was used to explore the possible risk factors for quality of life in myopia students. RESULTS: In the NEI VFQ-25, the total quality of life scores of myopia students (77.06 ± 15.66) were lower than those of normal vision students (85.49 ± 12.37). The difference was statistically significant (p = 0.007). In the correlation analysis, the total scores of quality of life in myopia students were positively correlated with wearing glasses (p = 0.049), and were negatively correlated with study time (p = 0.029). Multiple linear regression analysis showed that study time, wearing glasses and age were risk factors affecting quality of life in myopia students. CONCLUSION: Our results show that senior first-year myopia students have lower quality of life scores than students with normal vision. Study time, wearing glasses and age are risk factors for quality of life in senior first-year myopia students.