Cornmeal-induced resistance to ciprofloxacin and erythromycin in enterococci

Triclosan is used as an antibacterial agent in household items and personal care products. Since this compound is found in maternal milk of humans and bodies of wild animals, there is growing concern among some consumer groups and scientific community that triclosan is adverse for humans and wild animals. In order to estimate adverse actions of triclosan, the effects of triclosan on intracellular Zn²⁺ concentration and cellular thiol content were studied in rat thymocytes by the use of flow cytometer with appropriate fluorescent probes. Triclosan at 1-3 μM (sublethal concentrations) increased the intensity of FluoZin-3 fluorescence (intracellular Zn²⁺ concentration) and decreased the intensity of 5-chloromethylfluorescein (5-CMF) fluorescence (cellular thiol content). Negative correlation (r = −0.985) between triclosan-induced changes in FluoZin-3 and 5-CMF fluorescences was found. Removal of external Zn²⁺ did not significantly affect the triclosan-induced augmentation of FluoZin-3 fluorescence, suggesting an intracellular Zn²⁺ release by triclosan. These actions of triclosan were similar to those of H₂O₂ and triclosan significantly potentiated the cytotoxicity of H₂O₂. Therefore, the results may suggest that triclosan at sublethal concentrations induces oxidative stress that decreases cellular thiol content, resulting in an increase in intracellular Zn²⁺ concentration by Zn²⁺ release from intracellular store(s). Since recent studies show many physiological roles of intracellular Zn²⁺ in cellular functions, the triclosan-induced disturbance of cellular Zn²⁺ homeostasis may induce adverse actions on the cells.     

污水厂Carrousel氧化沟溶解氧和速度分布的研究

对长沙某污水处理厂的Carrousel氧化沟进行现场测试，获得不同截面的溶解氧和速度的数据，探讨了表曝机台数、沟深、沟的长宽比、进出水位置对溶解氧和速度的影响。初步掌握了该Carrousel氧化沟内溶解氧和速度的变化规律，认为通过调节倒伞形表面曝气机，可以在沟内不同区段创造好氧与缺氧的环境，为最终实现同步硝化反硝化的高效运行做准备。     

城市污水生物处理系统中微生物酶的活性及其分布

通过水解模式底物进行分光光度测定的方法,研究了城市污水生物处理系统中微生物酶的活性.选取亮氨酸氨基肽酶、β-葡萄糖苷酶、碱性磷酸酶和脂酶等胞外酶进行分析,结果发现4种胞外酶的平均活性在31.O～88.5 μmol/(L·h),其中76.9%～94.8%的酶活性分布在活性污泥中,说明绝大部分胞外酶是与细胞相连或固定在细胞外多聚絮体基质里.混合水样和出水水样中的DOC几乎相等,而各胞外酶与DOC不存在任何显著的相关关系.增加NO3-浓度可提高亮氨酸氨基肽酶和β-葡萄糖苷酶的活性,但对碱性磷酸酶和脂酶却有明显的抑制作用.     

Historical change of mercury pollution in remote Yongle archipelago, South China Sea

We collected three ornithogenic coral sand sedimentary profiles from Jinyin Island, Jinqing Island and Guangjin Island of Yongle archipelago, South China Sea and reconstructed the deposition flux of anthropogenic Hg over the past 700 years in the study area. On the whole, the anthropogenic Hg flux is relatively low; it remained at a low level before the Industrial Revolution with a small peak at about 1450-1550 AD, which may record the enhanced metallurgy activity in Ming Dynasty of China. During the 20th century, the deposition flux of anthropogenic Hg increased rapidly, but two troughs occurred during the periods around 1940s and 1970s, corresponding to the economic depression caused by World War II, Civil War in China (1945-1949), and the Culture Revolution (1966-1976) in China. Since the 1970s the deposition flux of anthropogenic Hg has been persistently increasing, apparently the result of fast economic development in East and Southeast Asia countries around South China Sea.     

Prenatal diagnosis of a fetus with terminal deletion of chromosome 1 (q41)

Many authors have suggested that individuals affected by a terminal 1q deletion display a phenotypically definable and recognizable syndrome. In all of the 27 cases reported to date, the breakpoints were at band q42 or distally to it. To our knowledge, we report the first case of a terminal 1q41 deletion. Diagnosis was made prenatally by amniocentesis, following ultrasonographic diagnosis of omphalocele, cerebral ventriculomegaly, and increased nuchal fold thickness in a 19-week female fetus. Multiple facial and extremity features were consistent with the proposed distal 1q deletion syndrome; omphalocele, however, has not been reported previously. The absence of liver herniation into the omphalocele sac in this case supports the previously reported association of this finding with chromosomal anomalies.     

地震安全性评价工作在城市建设中的重要作用

地震安全性评价工作在城市建设中起着非常重要的作用,为工程抗震提供精确的设计依据,提供科学合理的地震动参数,提出科学合理的设防要求,能够在一定程度上避免破坏性地震造成的损失,从而达到有效减灾的目的。     

大型河流大面积死鱼应急监测案例分析研究

以湖南湘江干流大面积死鱼突发环境事件为例,详细阐述了该事件开展应急监测的全过程,并就河流大面积死鱼突发环境事件应急监测方案、监测指标确定、原因分析等内容进行探讨。溶解氧低是死鱼的主要原因,而大体量低溶解氧污染团的形成与持续高温干旱天气、暴雨以及特殊的开闸放水方式有关。所分析的案例为死鱼事件应急监测工作提供借鉴和参考。     

株洲市工业区大气中SO2转化速率的研究

在湖南省株洲市工业区的下风向布点,同时测定大气中ＳＯ２的浓度、ＴＳＰ和＜０．２５μｍ细粒子中ＳＯ２－４的浓度．结果表明,大气中ＳＯ２浓度随着离污染源距离的增加迅速下降,和ＳＯ２相比,颗粒物中ＳＯ２－４浓度随距离的增加而降低的程度要慢得多．同步测定的ＳＯ２浓度和细粒子ＳＯ２－４浓度有显著的相关关系．根据风向、风速和新产生的细粒子中的ＳＯ２－４浓度及大气中ＳＯ２的浓度计算了株洲教育学院处ＳＯ２的转化速率,春季湿度大,ＳＯ２转化速率也大,为４．８％／ｈ,秋季湿度小,ＳＯ２的转化速率变低,为１．５％／ｈ．春季中路铺ＳＯ２转化速率为３．１％／ｈ．     

New process for anaerobic treatment of Vitamin C wastewater in a full scale plant

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Atmospheric depositional fluxes and sources apportionment of organochlorine pesticides in the Pearl River Delta region, South China

Organochlorine pesticides (OCPs) have variously been phased out in agricultural activities, but they are still widely detected in air, water, and soil systems due to their recalcitrant nature in the environment. The purposes of this study were to assess potential OCP pollution via dry and wet deposition over the fast developing Pearl River Delta area with 41,700 km², where the main effort has been focused on emerging pollutants such as petroleum hydrocarbons and PM2.5. We quantified both the dry and wet deposition fluxes of 19 OCPs including dichlorodiphenyltrichloroethanes (DDTs), endosulfans (Endos), and hexachlorocyclohexanes (HCHs). The results showed that each year about 67.4, 42.0, 15.0, and 8.07 kg of total OCPs, DDTs, Endos, and HCHs were returned to the ground, among which 11.7, 10.4, 0.84, and 0.16 kg were in the dry deposition forms. The large spatial variations in OCP deposition fluxes indicated that OCP pollution in the air is mainly influenced on local scales because evaporation from local soil is likely the major source of the phased out OCPs. Source analysis indicated that DDTs may be still in use as antifouling agent and/or dicofol, but Endos and HCHs were mainly derived from the residual of historical usage. The study suggests that the historical OCP pollutants are persistent at high levels in this area and should not be overlooked, while we tackle emerging pollutants.