Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 64
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Environ Res ; 252(Pt 4): 119107, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38723989

RESUMEN

Bioretention facilities have proven highly effective in removing pollutants from runoff. However, there is a concerning paucity of research on the contamination characteristics and associated risks posed by refractory pollutants in these facilities following long-term operation. This research focuses on the distribution, sources, microbial community impact, and human health risks of pollutants in eight bioretention facilities that have been operational for 5-11 years. The results showed that the distribution of Cu, Zn, and Cd was closely related to anti-seepage measures. PAHs, PCBs, and OCPs primarily accumulated in the surface, with concentrations ranging from 7.42 to 20.34 mg/kg, 31.8-77.3 µg/kg, and 60.5-163.6 µg/kg, respectively. Their concentrations inversely correlate with the depth of the media. Although the majority of contaminants remained below their respective risk thresholds, their concentrations typically exceeded those of background soil values, indicating an enrichment phenomenon. Source analysis revealed that PAHs primarily originate from oil combustion, PCBs were linked to their related industrial products, DDTs had their main sources in technical DDx and residues from the use of dicofol, while HCHs were traced back to historical residues from agricultural activities. Microbial α-diversity (Chao 1 and Shannon) decreased by 8.3-23.4% and 0.8-4.4%, respectively, in different facilities after long-term operation. The most dominant microbial phylum in the facilities was Proteobacteria (all relative abundances >48%). The total relative abundance of dominant genera was 6.7-34.3% higher than the control site, and Pseudomonas, a typical POPs-heavy metal degrading bacterium, had the highest relative abundance (>1.2%). Cu, Zn, and Cd present no non-carcinogenic risks and have low potential ecological risks. However, the lifetime cancer risk for PAHs is 10-6 ∼10-4 in most facilities and is of concern. The cancer risk for PCBs is acceptable, while OCPs pose a low cancer risk only for children.


Asunto(s)
Metales Pesados , Contaminantes Orgánicos Persistentes , Medición de Riesgo , Metales Pesados/análisis , Humanos , Monitoreo del Ambiente , Contaminantes del Suelo/análisis , Microbiota
2.
J Environ Manage ; 357: 120850, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38583384

RESUMEN

Climate change and urbanization contribute to the increased frequency of short-duration intense rainstorms. Traditional solutions often involve multiple scenarios for cost-effectiveness comparison, neglecting the rationality of placement conditions. The effective coupling and coordination of the location, number, size, and cost of storage tanks are crucial to addressing this issue. A three-phase approach is proposed to enhance the dynamic link between drainage pipeline and storage tanks in urban high-density built-up areas, integrating Python language, SWMM, the Elitist Non-Dominated Sorting Genetic Algorithm (NSGA-III), and the Analytic Hierarchy Process (AHP) methods. In the first stage, each node within the pipeline network is considered as a potential storage tank location. In the second stage, factors such as the length and diameter of the upstream connecting pipeline, as well as the suitability of the storage tank location, are assessed. In the third stage, the length and diameter of the downstream connecting pipeline node are evaluated. The results show that the 90 overflow nodes (overflow time >0.5h) have been cleared using the three-phase approach with a 50a (duration = 3h) return period as the rainfall scenario, which meets the flooding limitations. After the completion of the three-phase method configuration, the total overflow and SS loads were reduced by 96.45% and 49.30%, respectively, compared to the status quo conditions. These two indicators have decreased by 48.16 and 9.05%, respectively, compared to the first phase (the traditional method of only replacing all overflow nodes with storage tanks). The proposed framework enables decision-makers to evaluate the acceptability and reliability of the optimal management plan, taking into account their preferences and uncertainties.


Asunto(s)
Inundaciones , Lluvia , Reproducibilidad de los Resultados , Simulación por Computador , Urbanización
3.
Molecules ; 29(5)2024 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-38474488

RESUMEN

Supercapacitors (SCs) are a novel type of energy storage device that exhibit features such as a short charging time, a long service life, excellent temperature characteristics, energy saving, and environmental protection. The capacitance of SCs depends on the electrode materials. Currently, carbon-based materials, transition metal oxides/hydroxides, and conductive polymers are widely used as electrode materials. However, the low specific capacitance of carbon-based materials, high cost of transition metal oxides/hydroxides, and poor cycling performance of conductive polymers as electrodes limit their applications. Copper-sulfur compounds used as electrode materials exhibit excellent electrical conductivity, a wide voltage range, high specific capacitance, diverse structures, and abundant copper reserves, and have been widely studied in catalysis, sensors, supercapacitors, solar cells, and other fields. This review summarizes the application of copper-sulfur compounds in SCs, details the research directions and development strategies of copper-sulfur compounds in SCs, and analyses and summarizes the research hotspots and outlook, so as to provide a reference and guidance for the use of copper-sulfur compounds.

4.
J Cell Physiol ; 238(11): 2586-2599, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37795636

RESUMEN

Adolescent idiopathic scoliosis (AIS) is a complex disease characterized by three-dimensional structural deformities of the spine. Its pathogenesis is associated with osteopenia. Bone-marrow-derived mesenchymal stem cells (BMSCs) play an important role in bone metabolism. We detected 1919 differentially expressed mRNAs and 744 differentially expressed lncRNAs in BMSCs from seven patients with AIS and five patients without AIS via high-throughput sequencing. Multiple analyses identified bone morphogenetic protein-6 (BMP6) as a hub gene that regulates the abnormal osteogenic differentiation of BMSCs in AIS. BMP6 expression was found to be decreased in AIS and its knockdown in human BMSCs significantly altered the degree of osteogenic differentiation. Additionally, CAP1-217 has been shown to be a potential upstream regulatory molecule of BMP6. We showed that CAP1-217 knockdown downregulated the expression of BMP6 and the osteogenic differentiation of BMSCs. Simultaneously, knockout of BMP6 in zebrafish embryos significantly increased the deformity rate. The findings of this study suggest that BMP6 is a key gene that regulates the abnormal osteogenic differentiation of BMSCs in AIS via the CAP1-217/BMP6/RUNX2 axis.


Asunto(s)
Enfermedades Óseas Metabólicas , Escoliosis , Humanos , Adolescente , Animales , Escoliosis/genética , Escoliosis/patología , Osteogénesis/genética , Pez Cebra/genética , Columna Vertebral/metabolismo , Diferenciación Celular/genética , Enfermedades Óseas Metabólicas/genética , Enfermedades Óseas Metabólicas/metabolismo , Células Cultivadas , Células de la Médula Ósea/metabolismo , Proteína Morfogenética Ósea 6/genética
5.
Appl Environ Microbiol ; 89(7): e0025123, 2023 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-37306587

RESUMEN

Dimethylsulfoniopropionate (DMSP) and related organic sulfur compounds play key roles in global sulfur cycling. Bacteria have been found to be important DMSP producers in seawater and surface sediments of the aphotic Mariana Trench (MT). However, detailed bacterial DMSP cycling in the Mariana Trench subseafloor remains largely unknown. Here, the bacterial DMSP-cycling potential in a Mariana Trench sediment core (7.5 m in length) obtained at a 10,816-m water depth was investigated using culture-dependent and -independent methods. The DMSP content fluctuated along the sediment depth and reached the highest concentration at 15 to 18 cm below the seafloor (cmbsf). dsyB was the dominant known DMSP synthetic gene, existing in 0.36 to 1.19% of the bacteria, and was identified in the metagenome-assembled genomes (MAGs) of previously unknown bacterial DMSP synthetic groups such as Acidimicrobiia, Phycisphaerae, and Hydrogenedentia. dddP, dmdA, and dddX were the major DMSP catabolic genes. The DMSP catabolic activities of DddP and DddX retrieved from Anaerolineales MAGs were confirmed by heterologous expression, indicating that such anaerobic bacteria might participate in DMSP catabolism. Moreover, genes involved in methanethiol (MeSH) production from methylmercaptopropionate (MMPA) and dimethyl sulfide (DMS), MeSH oxidation, and DMS production were highly abundant, suggesting active conversions between different organic sulfur compounds. Finally, most culturable DMSP synthetic and catabolic isolates possessed no known DMSP synthetic and catabolic genes, and actinomycetes could be important groups involved in both DMSP synthesis and catabolism in Mariana Trench sediment. This study extends the current understanding of DMSP cycling in Mariana Trench sediment and highlights the need to uncover novel DMSP metabolic genes/pathways in extreme environments. IMPORTANCE Dimethylsulfoniopropionate (DMSP) is an abundant organosulfur molecule in the ocean and is the precursor for the climate-active volatile gas dimethyl sulfide. Previous studies focused mainly on bacterial DMSP cycling in seawater, coastal sediment, and surface trench sediment samples, but DMSP metabolism in the Mariana Trench (MT) subseafloor sediments remains unknown. Here, we describe the DMSP content and metabolic bacterial groups in the subseafloor of the MT sediment. We found that the tendency for vertical variation of the DMSP content in the MT was distinct from that of the continent shelf sediment. Although dsyB and dddP were the dominant DMSP synthetic and catabolic genes in the MT sediment, respectively, both metagenomic and culture methods revealed multiple previously unknown DMSP metabolic bacterial groups, especially anaerobic bacteria and actinomycetes. The active conversion of DMSP, DMS, and methanethiol may also occur in the MT sediments. These results provide novel insights for understanding DMSP cycling in the MT.


Asunto(s)
Agua de Mar , Compuestos de Sulfonio , Agua de Mar/microbiología , Bacterias , Sulfuros/metabolismo , Compuestos de Sulfonio/metabolismo
6.
J Environ Manage ; 347: 119135, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37797511

RESUMEN

Climate change is altering urban rainfall characteristics, leading to extreme urban stormwater and, particularly, more frequent flooding. Due to the uncertainty of climate change, the responses of urban drainage systems to climate change are becoming more complicated. This complexity makes it difficult for decision makers to assess whether urban infrastructure is sufficiently resilient to cope with flood risks. In this study, the Xiao Zhai area, a high-density urban area of China, was used as an example. A quantitative method for assessing these risks and the resilience of urban drainage systems to future urban stormwater was developed. First, based on the Coupled Model Intercomparison Project Phase 6 (CMIP6), the variation and uncertainty of future rainfall in the study area were analysed. A high-fidelity hydro-hydraulic model was developed to analyse the influence of climate change on future urban stormwater. Finally, the relationship between urban flood risk and the resilience of urban drainage systems was evaluated. The results show that the temporal distribution of future rainfall from 2023 to 2100 is relatively uniform. However, the number of heavy rainfall events increases significantly during this period. The flood risk caused by future rainfall was one level higher than the historical flood risk. For example, the flood risk caused by future 5a rainfall is equal to the flood risk from historical 10a rainfall. The correlations between the spatial distributions of flood risk and resilience are 0.49-0.63. Urban drainage systems urgently need to be improved and refined in areas with flood risk and low resilience to become more resilient to climate change. Rational planning of grey-green rainwater facilities in flood risk and low resilience areas can improve the rainwater system's resilience to 0.67-0.95 for climate change.


Asunto(s)
Cambio Climático , Inundaciones , Incertidumbre , Predicción , China , Ciudades
7.
J Environ Manage ; 330: 117148, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36584458

RESUMEN

Bioremediation techniques utilizing sulfate-reducing bacteria (SRB) for acid mine drainage (AMD) treatment have attracted growing attention in recent years, yet substrate bioavailability for SRB is a key factor influencing treatment effectiveness and long-term stability. This study investigated the effects of external organic substrates, including four complex organic wastes (i.e., sugarcane bagasse, straw compost, shrimp shell (SS), and crab shell (CS)) and a small-molecule organic acid (i.e., propionate), on AMD removal performance and associated microbial communities during the 30-day operation of sulfate-reducing microcosms. The results showed that the pH values increased in all five microcosms, while CS exhibited the highest neutralization ability and a maximum alkalinity generation of 1507 mg/L (as CaCO3). Sulfate reduction was more effective in SS and CS microcosms, with sulfate removal efficiencies of 95.6% and 86.0%, respectively. All sulfate-reducing microcosms could remove heavy metals to different degrees, with the highest removal rate of >99.0% observed for aluminum. The removal efficiency of manganese, the most recalcitrant metal, was the highest (96%) in the CS microcosm. Correspondingly, SRB was more abundant in the CS and SS microcosms as revealed by sequencing analysis, while Desulfotomaculum was the dominant SRB in the CS microcosm, accounting for 10.8% of total effective bacterial sequences. Higher abundances of functional genes involved in fermentation and sulfur cycle were identified in CS and SS microcosms. This study suggests that complex organic wastes such as CS and SS could create and maintain preferable micro-environments for active growth and metabolism of functional microorganisms, thus offering a cost-efficient, stable, and environmental-friendly solution for AMD treatment and management.


Asunto(s)
Desulfovibrio , Metales Pesados , Microbiota , Saccharum , Celulosa , Sulfatos/química , Metales Pesados/química , Ácidos , Desulfovibrio/metabolismo , Reactores Biológicos/microbiología
8.
J Clin Gastroenterol ; 56(7): 635-640, 2022 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-34653067

RESUMEN

GOAL: Our study aimed to explore the incidence of bleeding from ulcers due to premature band slippage and to identify possible associated factors. BACKGROUND: Band ligation (BL) plays a vital role in treating esophageal varices; however, the procedure carries a considerable risk of band slippage, variceal site ulcer formation, and posttreatment bleeding. MATERIALS AND METHODS: We retrospectively reviewed the records of patients with esophageal varices who underwent endoscopic hemostasis by BL at our institution between 2015 and 2020. We statistically compared the patients with post-BL ulcer bleeding and those without (controls). The outcome variable was the development of BL-induced ulcer bleeding. The patients' demographics, clinical, and laboratory parameters, and BL procedure parameters were independent variables. Univariate followed by a multivariate logistic regression were performed to identify possible associated factors from the odds ratio (OR). RESULTS: Of the 4579 eligible patients, 388 (8.5%) presented with post-BL ulcer bleeding. The presence of high-risk stigmata indicated a 1.271 times higher risk of bleeding [95% confidence interval (CI):1.018-1.587], and a greater number of varices was associated with an increased risk of post-BL ulcer bleeding [OR=1.184 (95% CI: 1.073-1.307)]. Conversely, the use of fewer bands per variceal site was associated with fewer bleeding incidents [OR=1.308 (95% CI: 1.090-1.569)]. Univariate analysis identified proton pump inhibitor as protective [OR=0.770 (95% CI: 0.603-0.983)]; however, the difference was not significant after multivariate analysis [OR=1.283 (95% CI: 1.003-1.640)]. CONCLUSIONS: The overall incidence of post-BL ulcer bleeding was 8.5%. The presence of high-risk stigmata, higher number of varices, and bands per variceal site were associated with an increased risk of post-BL bleeding. The effect of adjuvant proton pump inhibitors was not statistically significant.


Asunto(s)
Várices Esofágicas y Gástricas , Várices , Estudios de Casos y Controles , Várices Esofágicas y Gástricas/complicaciones , Várices Esofágicas y Gástricas/etiología , Hemorragia Gastrointestinal/tratamiento farmacológico , Hemorragia Gastrointestinal/epidemiología , Hemorragia Gastrointestinal/etiología , Humanos , Ligadura/efectos adversos , Ligadura/métodos , Cirrosis Hepática/complicaciones , Inhibidores de la Bomba de Protones/uso terapéutico , Estudios Retrospectivos , Úlcera/epidemiología , Úlcera/etiología
9.
Environ Res ; 212(Pt B): 113299, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35430279

RESUMEN

Almost all of the aerobic granular sludge (AGS) reactors were fed on certain amounts of Ca2+ ion, but whether and why it was necessary for reactor start-up remain unknown. Herein, this study conducted a set of comparative experiments in three AGS reactors, which were operated in parallel with Ca2+ addition in R3, hydroxyapatite (HAP) addition in R1, and without any forms of Ca addition in R2. Results showed that R3 not only achieved the complete granulation of sludge, but exhibited superior performance of COD and nutrient removal. In contrast, R1 had a slightly quicker granulation rate than R3 (R1: 0.07 day-1; R3: 0.06 day-1), but the formed granules could not efficiently degrade pollutants. In R2, both sludge granulation and pollutants removal did not proceed normally. Further investigations found that the Ca2+ ion acted in three ways: (1) it increased inorganic composition of sludge to promote granulation; (2) the transformed HAP strengthened stability of granular structure; (3) it ensured bioactivity of granules by driving enrichment of functional microbes and synthesis of metabolism enzymes. Overall, this study systemically proved significance of Ca2+ ion for the start-up of AGS reactors and its influencing mechanisms on different properties of granules.


Asunto(s)
Contaminantes Ambientales , Aguas del Alcantarillado , Aerobiosis , Reactores Biológicos , Aguas del Alcantarillado/química , Eliminación de Residuos Líquidos/métodos
10.
J Clin Pharm Ther ; 47(12): 1952-1965, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36452989

RESUMEN

WHAT IS KNOWN AND OBJECTIVE: The management of biological agents during pregnancy poses challenges as maternal and infant safety must be addressed. This study aims to compare the recommendations of existing guidelines on managing the use of biologics during pregnancy, lactation for patients with inflammatory bowel disease, and the influence on neonatal vaccination. METHODS: The PubMed, EMBASE, China National Knowledge Infrastructure, Wanfang database, China Science and Technology Journal Database and China Biomedical Database were systematically searched from the inception date to 11 May 2022, to screen all relevant guidelines. Quality assessment was performed using the guideline methodology reporting tool AGREE II. RESULTS AND DISCUSSION: Fourteen guidelines and consensus statements with detailed recommendations were included. All guidance documents cover management comments during pregnancy, and most consider that biologics can be given safely during pregnancy but require suspension at the right time to protect the foetus. However, the roles of vedolizumab and ustekinumab are disputed. Five documents guide lactation and the use of most biologics during lactation is safe, but no guidelines recommend vedolizumab. Six papers provide recommendations for newborns' vaccination, suggesting a delay in infants' live vaccination schedule if their mothers are treated with biologics. WHAT IS NEW AND CONCLUSION: Our study concluded that future guidelines could consider incorporating newer, more robust evidence to update recommendations. The development of future guidelines needs to consider the involvement of multidisciplinary experts, adequately report on the evidence retrieval process, and provide strategies for implementation. Besides, more research is needed to explore the use of biologics during pregnancy and lactation in patients with inflammatory bowel disease.


Asunto(s)
Productos Biológicos , Enfermedades Inflamatorias del Intestino , Embarazo , Femenino , Humanos , Recién Nacido , Productos Biológicos/uso terapéutico , Lactancia , Factores Biológicos , China , Enfermedades Inflamatorias del Intestino/tratamiento farmacológico
11.
Ecotoxicol Environ Saf ; 228: 112957, 2021 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-34775342

RESUMEN

Bioretention system is one of the most used green stormwater infrastructures (GSI), and its media is a key factor in reducing runoff water volume and purifying water quality. Many studies have investigated media improvement to enhance the pollutant removal capacity. However, the long-term cumulative effect and microbial effect of pollutants in the modified-media bioretention system is less known. This study investigated the cumulative effect of pollutants and their influence on microbial characteristics in conventional and modified media bioretention system. The addition of modifiers increased the background content of pollutants in the media, and the accumulation of pollutants in planting soil (PS) and bioretention soil mixing + water treatment residuals (BSM+WTR) was relatively higher after the simulated rainfall experiment. The accumulation of pollutants led to a decrease in dehydrogenase activity, and an increase in urease and invertase activities. Ten dominant bacterial species at the phylum level were found in all bioretention systems. The relative abundances of the bacteria with good viability under low nutritional conditions decreased, while the species which could live in the pollutant-rich environment increased. The accumulation of pollutants in the bioretention system led to the extinction of some functional microorganisms. The better the effects of modified media on pollutant removal showed, the more obvious effect on the media micro-ecosystem was. To ensure the long-term efficient and stable operation of the modified-media bioretention system, we recommend balancing the pollutant removal efficiency and cumulative effect in modified-media bioretention systems.

12.
J Surg Res ; 245: 475-482, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31446189

RESUMEN

BACKGROUND: The clinical characteristics of stage III colon cancer and the prognostic significance of tumor deposits were investigated, to construct a prognostic nomogram. METHODS: The data of patients were retrieved from the Surveillance, Epidemiology, and End Results database. Patients were randomized to a training or validation cohort. The Kaplan-Meier method was used to analyze survival rates. In the training cohort, a prognostic nomogram was established via Cox regression and then tested in the validation cohort. The accuracy and discrimination of the nomogram were assessed using concordance indices (C-indices) and calibration curves. RESULTS: Of the 9246 patients meeting the inclusion criteria, 1788 (19.3%) had tumor deposits. Patients with tumor deposits only showed similar survival rates to those with lymph node metastases only (P = 0.83). Compared with these, patients with both tumor deposits and lymph node metastases exhibited significantly worse survival (P < 0.01). In the multivariate Cox regression analyses, the following were identified as independent prognostic indicators and adopted to formulate the nomogram: tumor deposits, age, ethnicity, T stage, the number of positive regional lymph nodes, grade, and carcinoembryonic antigen. In the training cohort, the calibration curve showed good consistency, and the concordance index of the nomogram for predicting overall survival reaches 0.727 (95% CI: 0.71524-0.73876), superior to the concordance index of the American Joint Committee on Cancer staging system (0.594, 95% CI: 0.58224-0.60576). These results are supported in the validation cohort. CONCLUSIONS: Tumor deposits may be an independent prognostic factor for patients with stage III colon cancer after colectomy. The nomogram constructed herein accurately predicted overall survival.


Asunto(s)
Colectomía , Neoplasias del Colon/mortalidad , Extensión Extranodal/patología , Nomogramas , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Neoplasias del Colon/patología , Neoplasias del Colon/cirugía , Femenino , Humanos , Estimación de Kaplan-Meier , Ganglios Linfáticos/patología , Metástasis Linfática/patología , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Pronóstico , Estudios Retrospectivos , Factores de Riesgo , Programa de VERF/estadística & datos numéricos , Tasa de Supervivencia , Resultado del Tratamiento , Adulto Joven
13.
Water Sci Technol ; 81(5): 1039-1051, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32541120

RESUMEN

Many studies have been conducted on water volume reduction and pollutants purification of rain gardens. However, the pollutant variations in rain gardens are rarely explored. Seven soil sampling events were conducted from April 2017 to February 2019 to investigate the influences of stormwater concentration infiltration on soil heavy metals in two rain gardens. The results show that: (1) Cu, Zn, and Cd contents in rain garden soil are greater than those of the control soil. They vary with seasons and are trapped in the top layer of 0-30 cm; (2) Cu, Zn, and Pb exist as iron-manganese oxide combined form (S3), organic bound (S4) and residual forms (S5). However, Cd exists in exchangeable (S1) and carbonate bound (S2) forms, whereas Cr is in the S2, S3, and S4 forms. (3) According to the Soil Environmental Quality Standard in China, rain gardens, running for 8-9 years, are relatively clean and, within level II. However, compared with the background content of Shaanxi Province and the world, they are moderately or even heavily polluted by Cd and Zn and slightly polluted by Cu. It indicates that rain gardens have the risk of heavy metal pollution from stormwater concentration infiltration.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , China , Monitoreo del Ambiente , Jardines , Lluvia , Suelo
14.
J Environ Manage ; 217: 38-46, 2018 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-29587199

RESUMEN

The operation effects of bioretention on different tanks were investigated through tests and simulations. Three layered bioretention tanks, namely, #1, #2, and #3, were selected for intermittent operation tests. The artificial filler layers of the tanks consisted of mixed fillers of fly ash and sand, blast furnace slag, and planting soil. Models were established by using HYDRUS-1D software based on test results. The sensitivity of model parameters was analyzed through Morris screening method. Results showed that return period, thickness of media layer, and solute concentration in the liquid phase were the parameters that significantly influenced the operation effects. The Nash-Sutcliffe efficiency coefficients of the models were greater than 0.85. The simulation results showed that the reduction effects at different inflow loads were better under low loads than under high loads. The comprehensive reduction rate of pollutant load was 5.22% less under high concentrations than under low concentrations. The comprehensive reduction rates of water and pollutant loads were 35.97% and 20.68% greater, correspondingly, in the 1 year return period than in the 10 year return period. The artificial fillers comprising a mixture of fly ash and sand also showed the optimal reduction effects, with comprehensive reduction rates of 69.33% and 83.08% for water and pollutant load, respectively. The reduction effects of water and pollutants for the #1 tank presented an upward trend, whereas those for the #2 tank showed a downward trend given an increase in planting soil thickness. An increase in media thickness enhanced the reduction effects. The media with 60 cm thickness demonstrated the optimal effect.


Asunto(s)
Ceniza del Carbón , Dióxido de Silicio , Modelos Teóricos , Suelo
15.
Water Sci Technol ; 78(9): 1937-1945, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30566097

RESUMEN

In order to develop bioretention fillers with better phosphorus removal capacity, we built 12 bioretention columns with six kinds of modified fillers, and analyzed the operation effects of the columns under different conditions through field tests. Results show that adding water treatment residual has optimal removal rates for total phosphorus (TP) (median = 96.80%) and soluble reactive phosphorus (SRP) (median = 97.13%). The water reduction rates of the columns with improved fillers are 1.23-2.04 times that of the bioretention soil media column. The coconut chaff column has the best water storage capacity (median = 40.54%). Among the external factors affecting column operation, influent concentration of pollutants in urban surface runoff is the biggest influence factor on the removal efficiency of TP. However, there are no significant correlations between the removal efficiency of SRP and rainfall, influent concentration, and discharge ratio. The columns modified with medical stone, vermiculite, peat soil, medical stone + peat soil, green zeolite + peat soil all have good removal for phosphorus pollutant. After entering the columns, the contents of TP and SRP in most columns increased. The recommended fillers and the accumulation performance of phosphorus can help to improve purification effects in bioretention systems.


Asunto(s)
Fósforo/análisis , Lluvia , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos , Adsorción , Movimientos del Agua
16.
Sensors (Basel) ; 16(8)2016 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-27483272

RESUMEN

The use of a generalized sidelobe canceler (GSC) can significantly improve the lateral resolution of medical ultrasound systems, but the contrast improvement isn't satisfactory. Thus a new Eigenspace-based generalized sidelobe canceler (EBGSC) approach is proposed for medical ultrasound imaging, which can improve both the lateral resolution and contrast of the system. The weight vector of the EBGSC is obtained by projecting the GSC weight vector onto a vector subspace constructed from the eigenstructure of the covariance matrix, and using the new weight vector instead of the GSC ones leads to reduced sidelobe level and improved contrast. Simulated and experimental data are used to evaluate the performance of the proposed method. The Field II software is applied to obtain the simulated echo data of scattering points and circular cysts. Imaging of scattering points show that EBGSC has the same full width at half maximum (FWHM) as GSC, while the lateral resolution improves by 35.3% and 52.7% compared with synthetic aperture (SA) and delay-and-sum (DS), respectively. Compared with GSC, SA and DS, EBGSC improves the peak sidelobe level (PSL) by 23.55, 33.11 and 50.38 dB, respectively. Also the cyst contrast increase by EBGSC was calculated as 16.77, 12.43 and 26.73 dB, when compared with GSC, SA and DS, respectively. Finally, an experiment is conducted on the basis of the complete echo data collected by a medical ultrasonic imaging system. Results show that the proposed method can produce better lateral resolution and contrast than non-adaptive beamformers.


Asunto(s)
Aumento de la Imagen/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Ultrasonido/métodos , Ultrasonografía/métodos , Algoritmos , Humanos , Fantasmas de Imagen , Procesamiento de Señales Asistido por Computador , Programas Informáticos
17.
Sci Total Environ ; 946: 174278, 2024 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-38925397

RESUMEN

Bioretention systems prove effective in purifying common persistent organic pollutants (POPs) found in urban rainfall runoff. However, the response process of the microecosystem in the media becomes unclear when POPs accumulate in bioretention systems. In this study, we constructed bioretention systems and conducted simulated rainfall tests to elucidate the evolution of micro-ecosystems within the media under typical POPs pollution. The results showed all POPs in runoff were effectively removed by surface adsorption in different media, with load reduction rates of >85 % for PCBs and OCPs and > 80 % for PAHs. Bioretention soil media (BSM) + water treatment residuals (WTR) media exhibited greater stability in response to POPs contamination compared to BSM and pure soil (PS) media. POPs contamination significantly impacted the microecology of the media, reducing the number of microbial species by >52.6 % and reducing diversity by >27.6 % at the peak of their accumulation. Enzyme activities were significantly inhibited, with reductions ranging from 44.42 % to 60.33 %. Meanwhile, in terms of ecological functions, the metabolism of exogenous carbon sources significantly increased (p < 0.05), while nitrogen and sulfur cycling processes were suppressed. Microbial diversity and enzyme activities showed some recovery during the dissipation of POPs but did not reach the level observed before the experiment. Dominant bacterial species and abundance changed significantly during the experiment. Proteobacteria were suppressed, but remained the dominant phylum (all relative abundances >41 %). Bacteroidota, Firmicutes, and Actinobacteria adapted well to the contamination. Pseudomonas, a typical POPs-degrading bacterium, displayed a positive correlation between its relative abundance and POPs levels (mean > 10 %). Additionally, POPs and media properties, including TN and pH, are crucial factors that collectively shape the microbial community. This study provides new insights into the impacts of POPs contamination on the microbial community of the media, which can improve media design and operation efficiency.

18.
Sci Rep ; 14(1): 2, 2024 01 16.
Artículo en Inglés | MEDLINE | ID: mdl-38228664

RESUMEN

Rain gardens play a key role in urban non-point source pollution control. The drainage type affects the infiltration processes of runoff pollutants. The soil properties and microbial community structures were studied to reveal the stability of the ecosystem in rain gardens with different drainage types under long-term operation. The results showed that the soil water content and total organic carbon in the drained rain gardens were always higher than that of the infiltrated ones. With the increase in running time, the contents of heavy metals in rain gardens showed significant accumulation phenomena, especially the contents of Zn and Pb in drained rain gardens were higher than that in infiltrated ones. The accumulation of pollutants resulted in lower microbial diversity in drained rain gardens than in infiltrated rain gardens, but the microbial community structures were the same in all rain gardens. The effects of drainage type on microbial community evolution were not significant, only the accumulation of heavy metals led to changes in the abundance of dominant microorganisms. There were differences in the soil environment of rain gardens with different drainage types. The long-term operation of rain gardens led to fluctuations in the soil ecosystem, while the internal micro-ecosystems of the drained rain gardens were in unstable states.


Asunto(s)
Contaminantes Ambientales , Metales Pesados , Microbiota , Monitoreo del Ambiente , Jardines , Lluvia , Suelo/química
19.
Environ Sci Pollut Res Int ; 31(8): 12387-12405, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38233707

RESUMEN

The rapid development of the city leads to the continuous updating of the land use allocation ratio, particularly during the flood season, which will exacerbate the significant changes in the spatial and temporal patterns of urban flooding, increasing the difficulty of urban flood forecasting and early warning. In this study, the spatial and temporal evolution of flooding in a high-density urban area was analyzed based on the Mike Flood model, and the influence mechanisms of different rainfall peak locations and infiltration rate scenarios on the spatial and temporal characteristics of urban waterlogging were explored. The results revealed that under the same return period, the larger the rainfall peak coefficient, the larger the peak value of inundation volume and inundation area. When the rainfall peak coefficient is small, the higher the return period is, and the larger the peak lag time of the inundation volume is, in which P = 50a, r = 0.2, the peak lag time of the inundation volume reached 32 min and 45 min for the inundation depths H > 0.03 m and H > 0.15 m, respectively. There are also significant differences in the peak lag time of waterlogging inundation volume for different inundation depths. The greater the inundation depth, the longer the peak lag time of the inundation volume, and the higher the return period, the more significant the effect of lag time prolongation. It is worth noting that the increase in infiltration rate may lead to an advance in the peak time of inundation volume and inundation area, and the peak time of the inundation area is overall more obvious than that of inundation volume. The effect of infiltration rate on the peak time of inundation volume for larger inundation depths was relatively large; the peak times of inundation volume and inundation area were advanced by 4-6 min and 4-8 min for H > 0.03 m and H > 0.15 m, respectively, after the increase in infiltration rate, and the higher the rainfall return period, the longer the advance time. The spatial and temporal characteristics of waterlogging under different peak rainfall locations and infiltration capacities obtained in this study can help provide a new perspective for temporal forecasting and warning of urban waterlogging.


Asunto(s)
Inundaciones , Ciudades
20.
Sci Rep ; 14(1): 3910, 2024 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-38365944

RESUMEN

Facing to a planar tracking problem, a multiple-interpretable improved Proximal Policy Optimization (PPO) algorithm with few-shot technique is proposed, namely F-GBQ-PPO. Compared with the normal PPO, the main improvements of F-GBQ-PPO are to increase the interpretability, and reduce the consumption for real interaction samples. Considering to increase incomprehensibility of a tracking policy, three levels of interpretabilities has been studied, including the perceptual, logical and mathematical interpretabilities. Detailly speaking, it is realized through introducing a guided policy based on Apollonius circle, a hybrid exploration policy based on biological motions, and the update of external parameters based on quantum genetic algorithm. Besides, to deal with the potential lack of real interaction samples in real applications, a few-shot technique is contained in the algorithm, which mainly generate fake samples through a multi-dimension Gaussian process. By mixing fake samples with real ones in a certain proportion, the demand for real samples can be reduced.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA