Confirmation of polychlorinated biphenyl (PCB) distribution in the blood and verification of simple quantitative method for PCBs based on specific congeners

We measured the concentration of each polychlorinated biphenyl (PCB) congener in whole blood, plasma and blood cells, and investigated the distribution of PCBs in human blood using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). The PCB concentrations in plasma and whole blood in terms of lipid concentrations were almost equal, with a correlation coefficient of r = 0.972. In the blood, the ratio of PCBs in blood cells to those in plasma was generally about 1:9 and the congener distribution patterns in blood cells and plasma were similar.We performed verification of a simple mass screening method by obtaining information on the main PCB congeners for investigations on human accumulation and exposure. The total concentration of the seven PCB congeners (UNEP-7) proposed to the United Nations Environment Programme (UNEP) by Muir and Morita was about 50% of the total concentration of all PCB congeners, and UNEP-30 was about 80%. The seven main congeners in the blood (MCB-7) showed a value that was about 60%, and MCB-30 showed a value that was about 90%. Determinations with the main congeners in the blood showed a correlation of r = 0.990 or more between the main eight congeners (MCB-7 plus #74) and the total PCB concentration for all congeners. The results suggest that, although total PCB concentration can be effectively estimated from the main seven congeners, the main eight congeners would be preferable, and that the use of these congeners in the simple mass screening method would be effective for populations in areas uncontaminated by PCBs.     

模拟车用工况下5kW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20000 h^-1时,氢气的去除率能达到约95%,而当空速达到39270 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。     

Development of a hybrid microbial fuel cell (MFC) and fuel cell (FC) system for improved cathodic efficiency and sustainability: the M2FC reactor

In an effort to improve the efficiency and sustainability of microbial fuel cell (MFC) technology, a novel MFC reactor, the M2FC, was constructed by combining a ferric-based MFC with a ferrous-based fuel cell (FC). In this M2FC reactor, ferric ion, the catholyte in the MFC component, is regenerated by the FC system with the generation of additional electricity. When the MFC component was operated separately, the electricity generation was maintained for only 98 h due to the depletion of ferric ion in the catholyte. In combination with the fuel cell, however, the production of power was sustained because ferric ion was continually replenished from ferrous ion in the FC component. Moreover, the regeneration process of ferric ion by the FC produced additional energy. The M2FC reactor yielded a power density of up to 2 W m⁻² (or time-averaged value of approximately 650 mW m⁻²), density up to 20 times (or approximately six times based on time-averaged value) higher than the corresponding MFC system.     

Modulation of steroidogenesis by coastal waters and sewage effluents of Hong Kong, China, using the H295R assay

BACKGROUND, AIM, AND SCOPE: The presence of a variety of pollutants in the aquatic environment that can potentially interfere with the production of sex steroid hormones in wildlife and humans has been of increasing concern. The aim of the present study was to investigate the effects of extracts from Hong Kong marine waters, and influents and effluents from wastewater treatment plants on steroidogenesis using the H295R cell bioassay. After exposing H295R cells to extracts of water, the expression of four steroidogenic genes and the production of three steroid hormones were measured. MATERIALS AND METHODS: Water samples were collected during the summer of 2005 from 24 coastal marine areas and from the influents and effluents of two major waste water treatment plants (WWTPs) in Hong Kong, China. Samples were extracted by solid phase extraction (SPE). H295R cells were exposed for 48 h to dilutions of these extracts. Modulations of the expression of the steroidogenic genes CYP19, CYP17, 3betaHSD2, and CYP11beta2 were determined by measuring mRNA concentrations by real-time polymerase chain reaction (Q-RT-PCR). Production of the hormones progesterone (P), estradiol (E2), and testosterone (T) was quantified using enzyme linked immunosorbent assays (ELISA). RESULTS: Extracts from samples collected in two fish culture areas inhibited growth and proliferation of H295R cells at concentrations greater or equal to 10(5) L equivalents. The cells were exposed to the equivalent concentration of active substances in 10,000 L of water. Thus, to observe the same level of effect as observed in vitro on aquatic organisms would require a bioaccumulation factor of this same magnitude. None of the other 22 marine samples affected growth of the cells at any dilution tested. Twelve of the marine water samples completely inhibited the expression of CYP19 without affecting E2 production; inhibition of CYP17 expression was observed only in one of the samples while expression of CYP11beta2 was induced as much as five- and ninefold after exposure of cells to extracts from two locations. The expression of the progesterone gene 3betaHSD2 was not affected by any of the samples; only one sample induced approximately fourfold the production of E2. Although more than twofold inductions were observed for P and T production, none of these values were statistically significant to conclude effects on the production of these two hormones. While influents from WWTPs did not affect gene expression, an approximately 30% inhibition in the production of E2 and a 40% increase in P occurred for the exposure with influents from the Sha Tin and Stonecutters WWTPs, respectively. Effluents from WWTPs did not affect the production of any of the studied hormones, but a decrement in the expression of the aldosterone gene CYP11beta2 was observed for the Sha Tin WWTP exposure. No direct correlation could be established between gene expression and hormone production. DISCUSSION: Observed cytotoxicity in the two samples from fish culture areas suggest the presence of toxic compounds; chemical analysis is required for their full identification. Although effluents from WWTPs did not affect hormone production, other types of endocrine activity such as receptor-mediated effects cannot be ruled out. Interactions due to the complexity of the samples and alternative steroidogenic pathways might explain the lack of correlation between gene expression and hormone production results. CONCLUSIONS: Changes observed in gene expression and hormone production suggest the presence in Hong Kong coastal waters of pollutants with endocrine disruption potential and others of significant toxic effects. The aromatase and aldosterone genes seem to be the most affected by the exposures, while E2 and P are the hormones with more significant changes observed. Results also suggest effectiveness in the removing of compounds with endocrine activity by the WWTPs studied, as effluent samples did not significantly affect hormone production. The H295R cell showed to be a valuable toll in the battery required for the analysis of endocrine disrupting activities of complex environmental samples. RECOMMENDATIONS AND PERSPECTIVES: Due to the intrinsic complexity of environmental samples, a combination of analytical tools is required to realistically assess environmental conditions, especially in aquatic systems. In the evaluation of endocrine disrupting activities, the H295R cell bioassay should be used in combination with other genomic, biological, chemical, and hydrological tests to establish viable modes for endocrine disruption and identify compounds responsible for the observed effects.     

基于半经验模型对大面积染料敏化太阳电池性能影响因素的研究

以影响大面积染料敏化太阳电池性能的几个物理参量和几何参量为切入点,分析了内部电阻对电池性能的影响,针对几种构型不同的大面积电池,建立了效率的半经验模型.根据并联、串联、和各单元独立式串并联的大面积电池的相关物理参量和几何参量,对电池效率进行了计算.通过比较计算值与测试值的偏差,分析了半经验模型的适用性.在半经验模型的基础上,分析了相关物理参量和几何参量对电池性能的影响.结果表明,在实际应用中,通过半经验模型分析物理参量和几何参量的影响,可以优化大面积电池的性能.     

某涡轮风扇发动机试车台的声环境研究

涡轮风扇发动机试车台空气流量大,试车噪声呈宽带强噪声,其中突出的低频域噪声可远距离传播,易造成大范围的环境污染。为掌握某型涡轮风扇发动机在室内试车时的噪声特性,并检验试车台建筑物和各项降噪设备的效果,我们对新建试车台的声环境进行了测量。通过对该试车台内、外环境噪声数据的分析,表明新建试车台的声环境满足了我国有关规范的要求。本次研究工作对今后试车台的声学设计具有重要的借鉴意义。     

亚硝酸盐型甲烷厌氧氧化微生物特性研究进展

亚硝酸盐型甲烷厌氧氧化(nitrite-dependent anaerobic methane oxidation,N-DAMO)是新近发现的生物反应,是偶联碳氮循环的关键环节,是环境领域和微生物领域的重大发现.N-DAMO的发现对于完善碳氮生物地球化学循环、丰富微生物学内容和研发新型生物脱氮除碳工艺均具有巨大的推动作用.催化N-DAMO反应的微生物为Candidatus Methylomirabilis oxyfera(M.oxyfera),其隶属于一新发现的细菌门——NC10门.近年来,M.oxyfera的生物学研究取得了许多突破性进展,如初步探明了其个体形态特征、细胞化学组分特征、富集培养特征、生理生化特征及生态学特征,最突出的例子包括发现了M.oxyfera独特的细胞(星状)形态及特殊的脂肪酸(10Me C16∶1Δ7)组分等.最近,N-DAMO的机制研究方面也有了突破性进展:发现了地球上第4种生物产氧途径.目前认为,M.oxyfera具有内产氧功能,其首先将NO-2还原为NO,然后将2分子NO进行歧化反应生成N2和O2,最后利用生成的O2对甲烷进行氧化.本文系统地介绍了M.oxyfera各方面的微生物特性.     

铁氮掺杂碳纳米管/纤维复合物制备及其催化氧还原的效果

阴极催化剂是影响微生物燃料电池(microbial fuel cell,MFC)性能的关键因素.通过研究制备成本低廉、氧还原反应(ORR)催化活性高的阴极催化剂来替代Pt/C对于实现MFC规模化应用具有重大意义.研究采用化学气相沉淀法,以三聚氰胺作为碳氮前驱物、以黑珍珠2000或乙炔炭黑作为碳源,外加醋酸亚铁作为铁前驱物,合成了两种铁氮掺杂碳纳米管/纤维复合物(FeNCB和FeNCC),作为MFC的阴极催化剂.通过循环伏安法和旋转圆盘-环电极分析FeNCB、FeNCC和Pt/C的ORR催化活性的差异,并用MFC验证其差异.结果表明,FeNCB性能与Pt/C相当,优于FeNCC,其催化路径是通过4电子途径催化氧还原反应;MFC-FeNCB性能略优于MFC-Pt/C,显著优于MFC-FeNCB有助于MFC的扩大化,其最大功率密度为1 212.8mW·m~(-2),开路电压为0.875 V,电池稳定电压为(0.500±0.025)V.用X射线衍射、X射线光电子光谱、拉曼光谱等进一步分析显示,复合物中碳纳米管管径的大小、铁氮掺杂的类型和含量以及氧含量是引起制备的复合物催化氧还原性能差异的原因所在.