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The ecotoxicological effects of Cd²⁺ on germination and early seedling growth of six pulses were investigated. Seeds of these plants were exposed to seven different concentrations of Cd (0, 0.1, 0.2, 0.4, 0.8, 1.6, and 3.2 mM). The results indicated that root and coleoptile growth of six pulse plants were more sensitive than seed germination for measurement of toxic Cd²⁺ pollution. Different species show different levels of tolerance to Cd²⁺ pollution. V. angularis and Dumasia villosa are the most sensitive to Cd²⁺, and their germination percentage, and root and coleoptile growth were significantly lower than other tested species. By contrast, Vigna radiata and Lablab purpureus are the most resistant species, their germination and seedling growth almost were not influenced by Cd²⁺ pollution significantly compared to control. There were significantly negative correlations between seedling growth and increasing concentrations of Cd²⁺ for V. angularis. V. angularis and Dumasia villosa are the most sensitive to Cd²⁺. By contrast, Vigna radiata and Lablab purpureus are the most resistant species.
In this study, five mixed substrates – SSFGF, FSSGF, FSSFF, FSSFG, and FSFGF – consisting of fly ash, sludge, soil, fine cinder, gravels, and fine sand, were made in order to test the removal effect of lead. Multiple comparisons and analysis of variance were used to analyze physicochemical properties and the removal efficiency of lead. The test results showed that for five substrates, the effluent concentrations were not significantly different among 10 mg/L and 40 mg/L initial concentrations. For the other three initial concentrations (20 mg/L, 80 mg/L and 160 mg/L) from five substrates, it was significantly different. Moreover, when decomposition time was 0.25 h~48 h, the removal efficiency of Pb from the solution was better for substrate SSFGF-based wetland than those of the other substrate-based wetlands at low and medium initial concentrations (10 mg/L, 20 mg/L, 40 mg/L, and 80 mg/L), and then it was slightly better for substrate FSSFF-based wetland. At relatively high initial concentrations (160 mg/L), the removal efficiency was better for substrate FSSFF-based wetland than those of the other substrate-based wetlands, and then it was slightly better for substrate SSGFF-based wetland. Our study further suggested that SSFGF and FSSFF were the two relatively ideal substrate materials suitable for removal of Pb from a constructed wetland system.
To obtain sustainable aquaculture, developing appropriate treatment processes for wastewater is essential. In this study, two three-stage hybrid wetland systems were configured to treat aquaculture effluent. The two systems added with or without artificial aeration were operated under a high HLR (8.0 m/day) with a short retention time (0.96 h). By the results, COD could be effectively removed by both the systems, and it had been significantly enhanced by continuous aeration (air:water ratio being 7.5:1). For nitrogen (N) compounds, NH4+-N concentration of outflow compared to the inflow was elevated in most cases under the nonaerated condition, but an opposite trend was observed for the aerated state, which indicated that dissolved oxygen (DO) required for nitrification in the natural bed was more insufficient at the high organic loading rate. TN mass removal was efficient without aeration, but it significantly declined after enhancement, possibly due to the resuspension of trapped organic N promoted by the strong airflow. The artificial aeration also significantly improved the treatment performance on phosphorus. By canonical correspondence analysis (CCA), the first-order removal rate constants of various pollutants were significantly correlated to the measured environment of the inflow. Under the high constant HLR accompanied by low DO, pollutant loading rate became the first dependent factor on removal rate for such a rapid filtration system.
The effect of sludge biochars obtained at different temperatures on the adsorption of Cd(II) by loess in northwestern China was investigated using the batch equilibrium method. The results showed that the pseudo second-order kinetic model can describe the kinetics of Cd(II) adsorption on the sludge biocharamended loess very well. The adsorption of Cd(II) by loess reached equilibrium in 6h. However, with the addition of biochar, the adsorption time of the Cd(II) by loess decreased. In addition, the adsorption equilibrium time decreased significantly with increasing pyrolysis temperatures. When the pH increased from 2 to 7, the adsorption capacity of biochar-amended loess increased, while the adsorption capacity was in equilibrium or even slightly decreased in the pH range from 7 to 8. The Langmuir model can describe the adsorption isothermal behaviours of Cd(II) by biochar-amended loess. The adsorption capacity of biochar-amended loess samples for Cd(II) at 25°C follows the order of LSB700 (28.74 mg/g)>LSB500 (22.42 mg/g)>LSB300 (17.67 mg/g). The addition of sludge biochars can significantly improve the saturation adsorption capacity of loess for Cd(II). Therefore, the addition of sludge biochars can effectively improve the adsorption-immobilization capability of loess for Cd(II).
This study investigated the neuronal protective effect of monosialotetrahexosylganglioside (GM1) on the hypoxia-ischemia white matter damage (WMD) in neonatal rats. Brain hypoxia-ischemia was induced by bilateral carotid artery occlusion in 4-day-old neonatal rats. Bilateral carotid artery occlusion (BCAO) was performed in rats in WMD and GM1 groups, while in sham group; the rat bilateral carotid arteries were merely exposed without occlusion. Immunohistochemical staining was used to determine the expression of myelin basic protein (MBP), glial fibrillary acidic protein (GFAP), and P-amyloid precursor protein (P-APP). In addition, suspension test, slope test, and open-field test were carried out on day 26 after BCAO to determine the neurobehavioral function. The percentage of MBP-positive cells was decreased while P-APP-and GFAP- positive cells were increased in WMD group. After treated with GM1, the percentage of MBP-positive cells increased significantly than WMD rats at post-operation 72 h and day 7. GFAP-positive cells and P-APP-positive cells decreased significantly in WMD group at post-operation 72 h, day 7 and 26. The suspension test, slope test, and open-field test showed that neurobehavioral function was improved in ganglioside GM1 group compared with WMD group. Taken together, our findings suggested that ganglioside GM1 treatment reduces hypoxia-ischemia induced impairment of the neurobehavioral function in WMD in neonatal rats.
Heavy metal contaminations were assessed through a detailed soil survey in roadside soils along the Shenyang-Dalian Highway of Liaoning Province, China. Pb, Cu, Cd, Ni, and Zn were analyzed using atomic absorption spectrophotometry. The average concentrations of Pb, Cu, Cd, Ni, and Zn in roadside soils were 43.8, 26.5, 0.119, 32.1, and 71.3 mg/kg, respectively, and all concentrations exceeded the background values. Different heavy metal distribution patterns were found under different land use types. In farmland, a peak metal concentration occurred 25 m from the roadside soil, while in the forest and orchard soil all heavy metals decreased with distance from the roadside, which conformed to the exponential model. Heavy metal concentrations were markedly higher than those measured in 1999 and 2007, except for Cd. Concentrations in soils along the Shenyang-Dalian Highway were medium or low in comparison with roadside soils in other cities around the world. Overall, this assessment illustrates that heavy metal pollution in these soils is generally low, and we recommend that more attention should be given to Pb contamination in roadside soils along the Shenyang-Dalian Highway.
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