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.     

燃料电池发电系统安全与标准化

燃料电池因具有高效、节能、环保等优点,在电动汽车、分布式电站、便携式备用电源等方面具有广泛的应用前景,而燃料电池的安全标准是燃料电池产品市场准入的重要保证。燃料电池发电系统的安全涉及机械危险、电气危险、热危险、化学危害、物理危险、设备故障危险、因不适当的人机工程学原理而导致的危险及人机界面危险、合理预见的误用、环境条件危险、污染等方面。本文介绍了国内外燃料电池发电系统安全技术以及标准化的现状。     

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.     

核基因组在细胞质雄性不育中的作用研究：背景与现状

细胞质雄性不育 (ｃｙｔｏｐｌａｓｍｉｃｍａｌｅｓｔｅｒｉｌｉｔｙ ,ＣＭＳ) ,表现为小孢子发育异常、不能产生花粉或花粉败育 ,但卵细胞发育正常、可接受外来花粉而正常结实 ,系母性遗传 ,即细胞质遗传[1～ 4 ] .ＣＭＳ的重要性 ,首先表现为在农业生产上的巨大经济应用价值[2～ 4 ] .杂种优势的发现和利用为粮食生产带来了革命 ,但杂种种子的生产过程却是很繁杂的 ,核心是要阻止母本的自花授粉结实、保证母本植株上所结的种子全部是杂种 ,即种子的纯度很高才能保证农业生产上的应用 .ＣＭＳ ,由于其不能产生可育的花粉 ,即无自花授粉结…     

Power performance characterization of multi-crystalline silicon solar cells and its module at outdoor exposure

Outdoor power performance measurements of silicon (Si) solar cells and its assembled module were carried out at the coastal site of geographical location of 12.0107° Latitude and 79.856° Longitude, of Puducherry, India. Measurements were analyzed in comparison with the daily solar illumination data obtained by an optical pyranometer deployed with global measurement condition. It was found that the module required ~3 times more illumination to stabilize in its output voltage than the requirement of an individual cell and exhibited 11.35% loss in its efficiency compared to its STC value. Proposed operation of 5.30 hours was found resulting in an output rating fixed at ~40% from its 100% full capacity.     

电驱动道路车辆动力锂离子电池芯性能试验条件和要求

本文是电驱动道路车辆动力锂离子电池的试验和要求标题下的电池芯性能试验部分。结合国标转化过程和实验室能力验证经历,将锂离子电池芯的性能试验方法和要求作描述和解释。供实验室和相关产品的供需双方参考。     

The proton exchange membrane fuel cell systems using methanolysis of sodium borohydride as a hydrogen source with cobalt catalysts

Constant hydrogen generation via a hydrogen generator is evaluated from the methanolysis of sodium borohydride (NaBH₄) using Co/Al₂O₃ and MnO_x/Al₂O₃ catalysts. Chemical borohydrides coupled with catalysts can be used for compact storage and to create efficient generation systems. Thus, we first report the catalytic activity of MnO_x/Al₂O₃, which is synthesized using the simple wet-impregnation method, for the methanolysis reaction. The results indicate that both catalysts can effectively accelerate the methanolysis reaction and provide constant hydrogen generation rates. Thus, we integrate this hydrogen generation system into a proton exchange membrane fuel cell stack (PEMFC) to determine whether it can be used as a portable power supply. As a result, this fuel cell system operates at 40 W for 1 hr using the hydrogen source supplied from the catalytic methanolysis reaction.     

Biogas upgrading and utilization from ICEs towards stationary molten carbonate fuel cell systems

Biogas production from anaerobic digestion has increased rapidly in the last years, in many parts of the world, mainly due to its local scale disposition and to its potential on greenhouse gases (GHG) emissions mitigation. Biogas can be used as fuel for combined heat and power systems (CHP), in particular for internal combustion engines (ICEs). In recent investigations, fuel cells have been considered as alternative CHP systems. In the present article, two different energy conversion systems are compared: a 1.4 MW class MCFC system, running on pipeline natural gas, and an in situ ICE, running on biogas. In the first case, biogas is considered as a source fuel to obtain upgraded gas to be injected in the natural gas grid. In such scenario, the location of the fuel cell power plant is no longer strictly connected to the anaerobic digester site. Several energy balances are evaluated, considering different upgrading techniques and different biogas methane/carbon dioxide ratios.     

Photodynamic effects of 31 different phthalocyanines on a human keratinocyte cell line

Phthalocyanines (Pcs, colored macromolecular compounds with the ability to generate singlet oxygen) represent a promising group of photosensitizers due to their intense absorption in the red and UV portion of the spectrum which leads to their excitation. In order to characterize possible toxic effects associated with eventual practical use and application of these chemicals, we employed an in vitro cell culture model to evaluate cytotoxic effects of 31 different phthalocyanines using neutral red uptake assay. An immortalized human keratinocyte cell line HaCaT was exposed to the tested chemicals for 2 or 24 h, either with or without illumination in the last 60 min of the exposure period. After 2- or 24-h exposure without illumination, no cytotoxic effects or weak cytotoxic effects were induced by any Pc under the study and EC50 values could not be obtained within the tested concentration ranges (1.25–20 mg L⁻¹ or 0.625–10 mg L⁻¹). On the other hand, exposure to phthalocyanines under illumination induced a significant cytotoxic effect. The most pronounced cytotoxicity was elicited by Pcs previously shown to have high positive charge densities at peripheral parts of substituent groups, which is most likely the factor responsible for the binding of Pc to negatively charged membranes on the cell surface and thus guaranteeing the tight connection necessary for the singlet oxygen attack on the cell surface.     

Electrochemical removal of nitrate using ZVI packed bed bipolar electrolytic cell

The present study investigates the performance of the zero valent iron (ZVI, Fe⁰) packed bed bipolar electrolytic cell for nitrate removal. The packing mixture consists of ZVI as electronically conducting material and silica sand as non-conducting material between main cathode and anode electrodes. In the continuous column experiments for the simulated groundwater (initial nitrate and electrical conductivity of about 30 mg L⁻¹ as N and 300 μS cm⁻¹, respectively), above 99% of nitrate was removed at the applied potential of 600 V with the main anode placed on the bottom of reactor. The influx nitrate was converted to ammonia (20% to maximum 60%) and nitrite (always less than 0.5 mg L⁻¹ as N in the effluent). The optimum packing ratio (v/v) of silica sand to ZVI was found to be 1:1-2:1. Magnetite was observed on the surface of the used ZVI as corrosion product. The reduction at the lower part of the reactor in acidic condition and adsorption at the upper part of the reactor in alkaline condition are the major mechanism of nitrate removal.