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311.
氯化汞对小鼠睾丸生殖细胞的DNA损伤作用 总被引:4,自引:0,他引:4
探索氯化汞对雄性小鼠生殖细胞毒性的分子遗传机制。分别以 0 .0 1、0 .10、1.0 0 mmol/L的氯化汞体外处理小鼠睾丸细胞和以 0 .5、1.0、5 .0 μmol/kg的氯化汞体内暴露小鼠 ,应用单细胞凝胶电泳技术检测生殖细胞 DNA的损伤。体外处理 3种剂量组小鼠睾丸生殖细胞 DNA损伤率显著高于阴性对照组 ( 0 mmol/L组 ,P<0 .0 0 1) ;0 .1、1.0 mmol/L剂量组慧星细胞迁移率显著高于阴性对照组 ( P<0 .0 0 1,P<0 .0 5 )。体内暴露 3种浓度氯化汞组小鼠睾丸生殖细胞 DNA损伤率显著高于阴性对照组 ( 0μmol/kg,P<0 .0 0 1) ,5 .0 μmol/kg组慧星迁移率显著高于阴性对照组 ( P<0 .0 5 )。一定剂量的氯化汞处理引起生殖细胞 DNA损伤作用可能是氯化汞细胞毒性的机制之一。 相似文献
312.
印染废水生物强化处理技术研究进展 总被引:4,自引:0,他引:4
印染废水是国内外公认的难处理的工业废水之一 ,活性污泥法是目前最常用的处理方法 ,但还存在诸多问题。在分析中 ,主要从生物强化技术、固定化微生物技术和微生物活性增加技术等方面 ,总结了废水生物处理技术强化研究进展 ,并讨论了今后的研究方向。 相似文献
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Copper adsorption kinetic properties in batch and fixed-bed reactors were studied in this paper. The isothermal adsorption experiments showed that the copper adsorption capacity of a granular activated carbon (Filtrasorb 200) increased when ionic strength was higher. The presence of EDTA diminished the adsorption. An intraparticle diffusion model and a fixed-bed model were successfully used to describe the batch kinetic and fixed-bed operation behaviors. The kinetics became faster when the solution pH was not controlled, implying that the surface precipitation caused some metal uptake. The external mass transfer coefficient, the diffusivity and the dispersion coefficient were obtained from the modeling. It was found that both external mass transfer and dispersion coefficients increased when the flow rate was higher. Finally effects of kinetic parameters on simulation of fixed-bed operation were conducted. 相似文献
316.
Cadmium accumulation and elimination in tissues of juvenile olive flounder, Paralichthys olivaceus after sub-chronic cadmium exposure 总被引:1,自引:0,他引:1
Experiments were carried out to investigate the accumulation and elimination of cadmium (Cd) in tissues (gill, intestine, kidney, liver and muscle) of juvenile olive flounder, Paralichthys olivaceus, exposed to sub-chronic concentrations (0, 10, 50, 100 microg l(-1)) of Cd. Cd exposure resulted in an increased Cd accumulation in tissues of flounder with exposure periods and concentration, and Cd accumulation in gill and liver increased linearly with the exposure time. At 20 days of Cd exposure, the order of Cd accumulation in organs was gill > intestine > liver > kidney > muscle and after 30 days of exposure, those were intestine > gill > liver > kidney > muscle. An inverse relationship was observed between the accumulation factor (AF) and the exposure level, but AF showed an increase with exposure time. During the depuration periods, Cd concentration in the gill, intestine and liver decreased immediately following the end of the exposure periods. No significant difference was found Cd in concentration in the kidney and muscle during depuration periods. The order of Cd elimination rate in organs were decreased intestine > liver > gill during depuration periods. 相似文献
317.
Sorption of nonpolar (phenanthrene and butylate) and polar (atrazine and diuron) organic chemicals to oil-contaminated soil was examined to investigate oil effects on sorption of organic chemicals and to derive oil–water distribution coefficients (Koil). The resulting oil-contaminated soil–water distribution coefficients (Kd) for phenanthrene demonstrated sorption-enhancing effects at both lower and higher oil concentrations (Coil) but sorption-reducing (competitive) effects at intermediate Coil (approximately 1 g kg−1). Rationalization of the different dominant effects was attempted in terms of the relative aliphatic carbon content which determines the accessibility of the aromatic cores to phenanthrene. Little or no competitive effect occurred for butylate because its sorption was dominated by partitioning. For atrazine and diuron, the changes in Kd at Coil above approximately 1 g kg−1 were negligible, indicating that the presently investigated oil has little or no effect on the two tested compounds even though the polarity of the oil is much less than soil organic matter (SOM). Therefore, specific interactions with the active groups (aromatic and polar domains) are dominantly responsible for the sorption of polar sorbates, and thus their sorption is controlled by available sorption sites. This study showed that the oil has the potential to be a dominant sorptive phase for nonpolar pollutants when compared to SOM, but hardly so for polar compounds. The results may aid in a better understanding of the role of the aliphatic and aromatic domains in sorption of nonpolar and polar organic pollutants. 相似文献
318.
Dahe Jiang Yang Zhang Xiang Hu Yun Zeng Jianguo Tan Demin Shao 《Atmospheric environment (Oxford, England : 1994)》2004,38(40):7055
An air pollution index (API) reporting system is introduced to selected cities of China for public communication on air quality data. Shanghai is the first city in China providing daily average API reports and forecasts. This paper describes the development of an artificial neural network (ANN) model for the API forecasting in Shanghai. It is a multiple layer perceptron (MLP) network, with meteorological forecasting data as the main input, to output the next day average API values. However, the initial version of the MLP model did not work well. To improve the model, a series of tests were conducted with respect to the training method and structure optimization. Based on the test results, the training algorithm was modified and a new model was built. The new model is now being used in Shanghai for API forecasting. Its performance is shown reasonably well in comparison with observation. The application of the old model was only weakly correlated with observation. In 1-year application, the correlation coefficients were 0.2314, 0.1022 and 0.1710 for TSP, SO2 and NOx, respectively. But for the new model, for over 8 months application, the correlation coefficients are raised to 0.6056, 0.6993 and 0.6300 for PM10, SO2, and NO2. Further, the new algorithm does not rely on manpower intervention so that it is now being applied in several other Chinese cities with quite different meteorological conditions. The structure of the model and the application results are presented in this paper and also the problems to be further studied. 相似文献
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二氧化铈(CeO2)是一种性能优异的催化材料,已广泛应用于大气污染物的控制,这与其优异的储放氧性能即氧空穴的形成、消除相关;研究氧空穴在上氧物种的形成及活性对设计高效的铈基催化剂具有重要意义。X射线光电子能谱(XPS)、正电子湮没寿命谱(PAS)、氢气-程序升温还原(H2-TPR)研究结果表明,不同形貌的CeO2纳米材料上氧空穴团簇大小、相对强度、单位面积上Ce3+浓度的乘积与高活性氧物种的量之间呈线性相关,这一定量关系揭示氧空穴团簇是CeO2纳米材料上活性氧物种的捕集位点,对认识CeO2催化作用机制具有理论指导意义。 相似文献