Ethyl mercury induces Ca2+ uptake through the P2×7 receptor in a mouse cerebellar microglia cell line

Many observations are reported that organic mercury compounds are involved in increasing intracellular Ca²⁺ levels. However, the issue of which substances on the cell membrane participate in the Ca²⁺ uptake that is induced by ethyl mercury is unclear. The findings of this study suggest that the P2X receptor participates in this process. The uptake of Ca²⁺ by C8-B4 cells was induced in the presence of ethyl mercury. Ca channels in the cell membrane were not affected in this process. In contrast, pretreatment with suramin, an antagonist of the P2X receptor, inhibited the Ca²⁺ uptake induced by ethyl mercury, and also brilliant blue G, a nonselective antagonist of P2×4, P2×5, and P2×7 receptors. In addition, A438079 and A740003, selective antagonists of P2×7 receptor, reduced Ca²⁺ uptake, while 5-BDBD, a selective antagonist of P2×4 receptor, did not. Furthermore, the mRNAs of both the P2×4 and P2×7 receptors were expressed in the presence of ethyl mercury, but the P2×5 receptor mRNA was not. These findings suggest that ethyl mercury may induce Ca²⁺ uptake through the P2×7 receptor of the cell membrane.     

Trace analysis of airborne toluene diisocyanate as a pentafluorobenzyl derivative by gas chromatography with electron capture detection

Trace analysis of airborne toluene diisocyanate (TDI) vapor was accomplished by measuring the derivative using gas chromatography with electron‐capture detector after collecting gas samples with a microimpinger containing 2 ml toluene, 1 μl pentafluorobenzyl alcohol, and 1 μl triethylamine. The sampling efficiency was determined to be 99.4% for short‐term exposure level of TDI and the 2,4‐ and 2,6‐isomers of TDI were well separated. The derivative was identified to be a new compound with a molecular weight of 570 by mass spectrometry in fast atomic bombardment mode and nuclear magnetic resonance spectrometry. This method is convenient and can be applied in the field where airborne TDI is in vapor form.     

过氧化甲乙酮的热危险性研究

为研究过氧化甲乙酮(MEKPO)在运输与储存中的热危险性,利用差示扫描量热仪(DSC)对质量分数为52%的MEKPO溶液(以2,2,4-三甲基-1,3-戊二醇二异丁酸酯为溶剂)进行测试,得到其起始分解温度T0约为40℃,比放热量ΔH约为1.24 kJ/g。运用加速量热仪(ARC)对3种MEKPO溶液(40%,45%和52%)及MEKPO纯品(化学纯)在绝热条件下进行了热分解测试,并在此基础上,借助Semenov热爆炸模型,计算得到上述样品在50 kg包件下的自加速分解温度(TSADT)分别为65.64,63.72,55.88和51.17℃。研究结果表明,加入稀释稳定剂是降低MEKPO热危险性的有效途径,且MEKPO混合物中其质量分数越大,其危险性越高。     

基于QSPR方法的脂肪醇化合物闪点预测

为提高脂肪醇化合物闪点预测精度,提出基于定量结构-性质关系(QSPR)原理的脂肪醇化合物闪点预测方法。应用Dragon软件计算出91种脂肪醇的分子描述符,利用遗传函数算法(GFA)从1 481个描述符中筛选出3个与脂肪醇闪点关系最密切的分子描述符。分别用多元线性回归(MLR)方法和支持向量机(SVM)方法进行建模,并采用内部验证和外部检验的方式对模型的拟合度、预测性等性能进行验证。结果表明:预测集的MLR方法和SVM方法的平均绝对误差(AAE)分别为2.870 K和2.706 K;均方根误差(RMSE)为3.451 K和3.371 K。SVM模型在精度上略优于MLR模型,而MLR模型更为简单和方便。     

聚乙烯醇罐区火灾爆炸事故树分析

通过现场的调研与事故树分析相结合的手段对某厂聚乙烯醇车间聚合罐区火灾爆炸事故的危险因素进行了识别与分析.以该罐区可能发生的火灾爆炸事故作为顶上事件,对可能引发顶上事件的21个基本事件及一个条件事件构建事故树,利用最小割集、最小径集及结构重要性计算手段进行事故风险程度分析,从而确定醋酸乙烯暴聚是聚合罐区的首要危险源,而促发醋酸乙烯暴聚的物料长时间停留、气相氧含量过高、温度控制失效、阻聚剂含量不足等四个基本事件是导致聚合罐区火灾爆炸事故的最危险因素.本文对以上聚合罐区发生火灾爆炸事故的风险因素进行详细定性分析,并在此基础上有针对性的提出了相应的安全预防控制措施.同时,该聚合罐区的事故树分析结论也可以为同类别化工单位罐区的日常运行、设计改造、维护保养等工作提供理论依据.     

Ko method of quantification in neutron activation analysis as applied to environmental samples

The _Ko factor method in neutron activation analysis adopts all the principles of comparator method and can be used for the rapid determination of elemental comcentrations during routine monitoring of environmental samples. The method necessiates the use of same in-pile conditions, such as irradiation time, irradiation position and the type of neutron spectrum, for which the factors have been generated. The _{K_o} factors were estimated for various elements of environmental importance for three irradiation positions of Apsara Reactor at Bhabha Atomic Research Centre. Standard reference materials of soil and coal were used for all the elements except for Hg for which HgCl₂ was used. The concentration of the elements determined using these factors in a flyash standard reference material revealed good agreement within 10% of the certified values. The efficacy of the method compared well with that of specific element comparator method as revealed by the elemental concentrations obtained by both the techniques.     

小麦秸秆生物炭对水中对羟基苯甲酸乙酯的吸附特性

对羟基苯甲酸乙酯属于尼泊金酯类物质,是一种典型的新兴环境污染物.本研究通过制得不同热解温度(300、500和700℃)下的小麦秸秆生物炭(分别表示为BC300、BC500、BC700),对水中对羟基苯甲酸乙酯进行间歇吸附.结果表明,热解温度升高会导致生物炭表面疏水性增强,且引起零电荷点从8.37升至9.42.溶液初始p H值由8升至12时,对羟基苯甲酸乙酯去除率显著递减;此外,溶液离子强度的增强会导致对羟基苯甲酸乙酯去除率的下降.生物炭吸附水中对羟基苯甲酸乙酯的等温吸附过程符合Langmuir方程,其中,最大吸附容量排序为:BC700BC500BC300.同时,吸附过程符合准二级动力学方程,且为吸热自发过程.此外,经过4轮再生吸附,生物炭吸附容量仍可达到最初的90%,其中,BC700展示出最高的吸附效率(92.76%).     

铁碳微电解预处理高浓度酒精废液

采用废铁屑-焦碳组成微电解工艺预处理高浓度酒精废液。通过正交试验和单因素分析试验考察了反应时间、铁碳比、曝气强度对铁碳微电解工艺降解有机物,提高废水可生化性和pH的影响,最终确定了最佳反应条件。试验结果表明,反应时间、铁碳比和曝气强度对铁碳微电解处理酒精废液的影响程度依次降低,且最佳反应条件为反应时间2小时,铁水比125：500,曝气强度4m^3／m^2h,CODcr的去除率达到50％,废水的BOD5／CODcr值可由O．3提升到0．48,pH由3．5提高到5．2左右。作为高浓度酒精废液预处理工艺,铁碳微电解能够经济、有效降低后续处理工艺的负荷,提高废水的可生化性和碱度。     

茅台酒原产地域研究概述

本文介绍了茅台酒原产地研究概况,主要从原产地的界定,其地质背景、生态环境、以及茅台酒独特的生产工艺等方面进行了总结,加强茅台酒的原产地保护刻不容缓.     

退浆废水中聚乙烯醇定量测量的研究进展

中国纺织行业产生的退浆废水中聚乙烯醇（PVA）可生化性能差,其对环境的危害越来越受到环保人士的关注。因此定量检测PVA在处理退浆废水研究中显得尤为重要,然而至今没有形成一套定量测量PVA的规范方法。本文介绍了目前退浆废水中聚乙烯醇定量测量的常用方法：单波长和双波长分光光度法,以及目前测量所选用的显色体系、显色剂加入量、测量波长等条件。并从多角度分析了测量条件不规范的原因,提出了一些改进的建议,为规范PVA的定量测量研究提供参考。