温度盐度和光照条件对赤潮异弯藻细胞稳定性的影响

研究了温度、盐度和光照的不同组合条件对赤潮异弯藻(Heterosigma akashiwo Hada)种群生长过程中细胞相对稳定性的影响.结果表明,在温度(10、20和27℃)、盐度(10～50)和光照(高:4500～5000lx;低:1500～2000 lx)的组合条件下,细胞稳定性表现出明显差异:10℃环境温度对细胞维持相对稳定性显著有利.该温度下的各盐度和光照组合中,细胞相对稳定性比值r(固定后破裂细胞/细胞总数)始终为0,并且在整个实验周期中维持好的稳定状态;在20和27℃条件下,种群生长初期,细胞能维持较好的稳定性,r 值低,种群迅速生长时,细胞的稳定性显著减弱.     

Developing a passive air-breathing tubular direct methanol fuel cell fed with concentrated methanol

This study develops and investigates a fully passive air-breathing tubular direct methanol fuel cell (t-DMFC) with a steel-tube anode and a steel-mesh cathode. The effects of methanol concentration, cathode catalyst loading, mesh structure, and forced air convection are experimentally explored. Results indicate that the t-DMFC performs better at a relatively higher methanol concentration of 8 M. It is recommended to use a catalyst loading of 4 mg cm^?2. Both the electrochemical impedance spectroscopy (EIS) and performance tests confirm that the 40-mesh setup is preferred at the cathode. The fuel cell yields a poor performance when the cathode works with forced air convection because the air-blowing operation reduces the cell temperature and this effect dominates the cell performance. The dynamic and constant-load behaviors are also inspected.     

微电池滤床法处理含油废水

介绍了含油废水中油珠电荷的来源和ζ－电位,阐述了液膜池微观电泳测试的理论和方法。根据油珠具有ζ－电位及在外电场作用下可以迁移的性质,采用炭－铁粒料组成微电池滤床处理含油废水,油去除率可达７０％－８０％。     

Chromosomal aberrations and DNA damage in human populations exposed to the processing of electronics waste

Background, aim, and scope  It has been known that the pollutants of electronic wastes (E-wastes) can lead to severe pollution to the environment. It has been reported that about 50% to 80% of E-wastes from developed countries are exported to Asia and Africa. It has become a major global environmental problem to deal with ‘E-wastes’. E-waste recycling has remained primitive in Jinghai, China. This not only produces enormous environmental pollution but also can bring about toxic or genotoxic effects on the human body, threatening the health of both current residents and future generations living in the local environment. The concentration of lead in the blood of children in the E-waste polluted area in China is higher than that of the control area. But little is known about the cytogenetic effect to human beings caused by the pollution of E-wastes. In the present study, experiments have been performed to investigate the genetics of permanent residents of three villages with numerous E-waste disposal sites and to analyze the harmful effects of exposure to E-wastes. Materials and methods  In total, 171 villagers (exposed group) were randomly selected from permanent residents of three villages located in Jinghai County of Tianjin, China, where there has been massive disposal of E-wastes. Thirty villagers were selected from the neighboring towns without E-waste disposal sites to serve as controls. Chromosomal aberrations and cytokinesis blocking micronucleus were performed to detect the cytogenetic effect, dic + r (dicentric and ring chromosome), monomer, fragments (acentric fragments, minute chromosomes, and acentric rings), translocation, satellite, quadriradial, total aberrations, and micronuclear rate were scored for each subject. DNA damage was detected using comet assay; the DNA percentage in the comet tail (TDNA%), tail moment (TM), and Olive tail moment (OTM) were recorded to describe DNA damage to lymphocytes. Results  The total chromosome aberration rates (5.50%) and micronuclear rates (16.99%) of the exposure group were significantly higher than in the control group (P = 0.000). The percentage of DNA in the comet tail, tail moment, and Olive tail moment detected by comet assay showed that there was a significant difference in DNA damage in the exposure group (P = 0.000). The chromosome aberration, micronucleus rate, and DNA damage observed in women were significantly higher than those in men. Chromosome aberration and micronuclear rates of both smokers and non-smokers in the exposure group are obviously higher than that in the control group (P = 0.000). Discussion  The use of outdated (and unsafe) ways to deal with E-wastes can lead to exposure to a variety of substances harmful to human health. The components of pollution may enter the human body through the air, drinking water, and food chain to damage human genetic material, resulting in genomic instability. The rates of chromosomal aberration, micronucleus formation, and the degree of DNA damage in women in the group exposed to electronic waste were significantly higher than in men. The reason for this may be concerned with the traditional lifestyle of the local residents or the difference of sensitivity to the exposure to E-wastes or any others. Further investigations are needed to provide evidence to demonstrate this. Conclusions  Here, we report the obviously cytogenetic toxicity to the exposure population by the E-waste pollution for the first time. E-waste pollution may be a potential agent of genetic mutation, and may induce cytogenetic damage within the general population exposed to the pollution. These findings need to be considered, and steps should be taken to protect the current population and future generations from the effects of pollution with E-wastes. Recommendations and perspectives  The above results remind us that the impact of E-waste recycling on environmental quality of Jinghai should be evaluated soon. Moreover, it is urgent for the government to prohibit E-waste import and its processing by outdated ways. The future studies such as pollutant details of drinking water, air, and soil in the area as well as epidemiological investigations on the harmful effect to children must be performed eagerly. All the data available do provide a compelling case for immediate action in both countries to address workplace health and safety and waste management. Qiang Liu and Jia Cao contributed equally to this study and share the first authorship.     

化学防护服的氢氧化钠渗透性能离子色谱检测方法的研究

渗透性能是化学防护服最重要的防护性能指标之一.本文利用PTC200型渗透测试池、蠕动泵和离子色谱仪等装置,研究并建立了NaOH溶液的渗透性能离子色谱仪的检测方法.结果表明,利用该装置可以方便准确地实现服装面料NaOH溶液渗透性能测试,是一种具有重要应用价值的检测方法.     

模拟车用工况下5 kW燃料电池尾气净化系统

模拟了车用工况下燃料电池发动机脉冲式排氢的特点,设计开发了一套质子交换膜燃料电池的尾气净化系统,并以5 kW燃料电池的尾气排放为例,研究其净化效果。研究了电池阳极排放氢气缓冲前后尾气中氢气浓度的变化,以及不同空速条件下氢气的去除效果。结果表明：电堆阳极排放氢气经过缓冲处理后,尾气中氢气浓度趋于平稳,大部分工况下处在2%以下,达到了安全处理的要求;尾气中氢气的去除效果与空速密切相关。对自制的整体式催化剂而言,当空速低于20 000 h^-1时,氢气的去除率能达到约95%,而当空速达到39 270 h^-1时,氢气的去除率仅为10.9%。鉴于这一问题,提出通过采用尾排空气的分流手段调整催化燃烧反应器对空速的要求,以提高尾气中氢气的去除率。     

不同氯离子浓度对电化学法处理微污染水中含氮化合物的影响

采用电化学氧化法对微污染水进行处理,在极板间距为1 cm,电解时间为10 min的条件下,通过投加NaCl溶液,使水中的NH4+及Cl-的摩尔比分别为1∶1、1∶2、1∶3,并与未投加NaCl溶液的电解出水进行比较,主要考察不同氯离子浓度对电化学法去除微污染水中的含氮化合物的效果影响.实验表明:随着氯离子浓度的不断提高...     

微波污泥上清液为燃料的微生物燃料电池内阻分布

实验采用单室无膜悬浮阴极微生物燃料电池（MFC）,考察了微波污泥上清液为燃料的MFC（MSMFC）的内阻组成。研究表明,当未投加氯化钠时,MSMFC内阻为486．13Ω。当投加100mmol／L的氯化钠时,内阻迅速下降为207．18Ω。而投加量进一步增加时,内阻变化不明显。当阳极面积从4cm2增加到8cm2时,MSMFC内阻从387．34Ω迅速下降到293．96n。而当阳极面积增加到24cm。时,MSMFC内阻变化不明显。但当阳极面积增加到60cm2时,MSMFC内阻下降了38．4％。当阴极面积从24．87cm2增加到49．74cm2时,MSMFC内阻减少了40．4％（从545．72Ω减少到220．56Q）。MSMFC中阳极内阻占主要部分,其次为阴极内阻,电解液电阻最小。随着阴阳极面积比的增加,阴阳极电阻比例减少,说明控制阴阳极面积比可以调整系统内阻的分配。     

Cell absorption induced desorption of hydrophobic organic contaminants from digested soil residue

Oral ingestion of contaminated soil is an important pathway of human exposure to hydrophobic organic contaminants (HOCs), particularly for children in developing countries. The mobilization potential of various contaminants from ingested soil is often characterized using an in vitro gastrointestinal model, based on the quantities of contaminants remaining in digestive fluid after digestion and separation. Recently, it was experimentally demonstrated that a large fraction of mobilized contaminants sorbed on the digested residue could be released if the dissolved fraction was removed by intestinal absorption. This hypothesis was further tested in this study. Soil spiked with dichlorodiphenyltrichloroethane and its metabolites (DDXs) and polycyclic aromatic hydrocarbons (PAHs) was digested using an in vitro gastrointestinal model. A human colon carcinoma cell line (Caco-2) was cultured in digestive fluid with or without soil residue (pre-equilibrated with the soil) for 2 h. A large proportion of the contaminants (37-68%) was sorbed on the digested residue. Without this residue, 66 ± 13% of DDXs and 73 ± 14% of PAHs dissolved in the fluid, as means and standard deviations, were absorbed by the cell monolayer after exposure. With both digestive fluid and residue, the sorbed fraction of PAHs and DDXs decreased by 38-92%, while the ratios of the cellular to the dissolved concentrations were 2.7-2.8 times higher than those without the residue. This supported the hypothesis that the cell absorption of dissolved HOCs induces desorption of the sorbed fraction from digestive residue, and the desorbed HOCs can be absorbed as well.     

Changes in cell-type composition in digestive gland of slugs and its influence in biomarkers following transplantation between a relatively unpolluted and a chronically metal-polluted site

Changes in cell-type composition (CCTC) is a general phenomenon that takes place in the digestive gland epithelium of stressed molluscs. The aim of the present work was to determine whether CCTC is a reversible process in the digestive gland of sentinel slugs chronically exposed to metal pollution and how CCTC affects metal accumulation parameters and different cell and tissue biomarkers of exposure and effect. Slugs (Arion ater) from an abandoned zinc mine were transferred to a relatively unpolluted site and the other way around for 3, 10 and 28 d. The volume density of black silver deposits (Vv_BSD) after autometallography, and metallothionein (MT) levels were used as biomarkers of exposure to metals and CCTC and lysosomal responses were selected as effect biomarkers. Results indicated that slugs were sensitive to recent metal pollution; however, slugs chronically exposed to metals presented some characteristic features and were less responsive to pollution cessation without signs of CCTC reversal.