AlEtCl2／t—BuCl引发α—蒎烯阳离子阳合的反应研究

在实验室绝热反应器中进行了乙苯脱氢制苯乙烯的反应动力学研究。根据不同反应机理，提出五种反应模型，经残差分析及模拟计算规律与实验规律的比较，确定Ｃａｒｒａ双曲模型为最佳反应动力学模型。通过对实验数据的回归拟合，经参数估计求得了速率方程的频率因子和活化能。     

Acute bone marrow toxicity and pancytopenia following exposure to lead chromate,xylene, and ethylbenzene in a degloving injury

A case of unique acute bone marrow toxicity and pancytopenia following subcutaneous exposure to lead chromate, xylene, and ethylbenzene in a previously healthy patient is reported. The patient sustained an extensive degloving injury to his lower extremity. The wound was contaminated with traffic paint containing lead chromate pigment along with a large volume of xylene and ethylbenzene solvent. Consequences of the patient's clinical course and management of degloving injuries are discussed. © 1994 Wiley-Liss, Inc.     

乙苯/苯乙烯生产过程的优化运行研究

针对乙苯/苯乙烯实际生产装置,分别建立了烷基化、烷基转移、乙苯精馏、乙苯脱氢、苯乙烯精馏生产过程的机理模型,该机理模型与实际生产过程误差范围在2%左右。以该模型为基础进行系统优化操作设计,生产装置实际运行结果表明：基于该优化操作系统,可有效降低装置的能耗,为其他乙苯/苯乙烯装置的优化运行奠定了基础。     

空气中乙苯的热解吸气相色谱法

用活性炭采集空气中的乙苯,然后于350℃解吸,将解吸气收集在注射器中,用气相色谱仪分析.文中对解吸温度、解吸体积及共存苯系物对解吸效率的影响等进行了试验,结果表明解吸100ml即可达到稳定,共存的苯、甲苯、二甲苯对乙苯的解吸效率无影响.     

Transition Metal Salts of Carboxylated Multiwalled Carbon Nanotubes in Combination with N-hydroxyphthalimide as Catalytic Systems for Hydrocarbon Oxidation

In this study, the transition metal (Co (II), Cu (II), and Mn (II)) salts of carboxylated carbon nanotubes were synthesized and characterized (the determined metal contents were in the range of 0.89–1.16%). The catalytic activity and the possibility for recovery and reuse of the obtained heterogeneous salts were then studied in the solvent-free oxidation of ethylbenzene with oxygen. The oxidation processes were carried out at 80 °C under atmospheric pressure in the presence of N-hydroxyphthalimide. The highest conversion of ethylbenzene, 27%, was obtained with a system consisting of the Cu (II) salt of the carboxylated carbon nanotubes, N-hydroxyphthalimide, and the azo initiator AIBN.     

Developmental toxic effects of ethylbenzene or toluene alone and in combination with butyl acetate in rats after inhalation exposure

First, the developmental toxic potential of n-butyl acetate (BA) was examined in Sprague-Dawley rats following whole body inhalation exposure, 6 h day(-1), from day 6 to 20 of gestation, at concentrations of 0, 500, 1000, 2000 and 3000 ppm. Maternal toxicity was evidenced by significant decreases in body weight gain at 2000 and 3000 ppm, and by reduced food consumption at 1000 ppm and higher concentrations. The effects on prenatal development were limited to a significant decrease in fetal weight at 3000 ppm. Thus, inhaled BA was not a selective developmental toxicant. In the second part of this study, the developmental toxic effects of simultaneous exposures to ethylbenzene (EB) and BA, or to toluene (TOL) and BA were evaluated. Pregnant rats were administered EB (0, 250 or 1000 ppm) and BA (0, 500 or 1500 ppm), or TOL (0, 500 or 1500 ppm) and BA (0, 500, 1500 ppm), separately and in combinations, using a 2 x 2 factorial design. The maternal weight gain was reduced after exposure to 1000 ppm EB, to 1500 ppm BA, or to 1500 ppm TOL, either alone or in binary combinations. A significant reduction of fetal weight was associated with exposure to 1000 ppm EB alone, to either mixtures of EB with BA, or to 1500 ppm TOL alone or combined with BA at either concentration. No embryolethal or teratogenic effects were observed whatever the exposure. There was no evidence of interaction between EB and BA or between TOL and BA in causing maternal or developmental effects.     

车间空气中乙苯最高容许浓度的研究

劳动卫生学调查表明了，甲厂（生产乙苯车间）各作业点空气乙苯浓度为０．０５～１６．６ｍｇ／ｍ＾３，乙厂（使用车间）为０．０５～２３ｍｇ／ｍ＾３。从甲厂临床体检及化验表明，工人的临床表现，血尿常规检查及肝功能与对照组比较未发现明显改变，然而接触组工人（平均工龄１２．６年）尺神经感觉神经传导速度和右眼模式翻转视觉诱发电位Ｎ２波潜伏期比对照组显著延长。根据所获结果，结合文献报道和毒理学资料，建议车间空气中     

空气中乙苯的热解吸气相色谱法

用活性炭采集空气中的乙苯,然后于350℃解吸,将解吸气收集在注射器中,用气相色谱仪分析。文中对解吸温度、解吸体积及共存苯系物对解吸效率的影响等进行了试验,结果表明解吸100ml即可达到稳定,共存的苯、甲苯、二甲苯对乙苯的解吸效率无影响。     

Roles of oxidative damage and mitochondria-mediated apoptosis in ethylbenzene-induced hepatotoxic effects in rat

Abstract

The mechanisms underlying hepatoxic effects of ethylbenzene still remain unknown. We investigated the toxic effects of ethylbenzene on liver and explored the mechanism of mitochondria-mediated apoptosis pathway. Forty male Sprague-Dawley rats were used as an in vivo model with ethylbenzene inhalation of 0, 433.5?mg/m³, 4335?mg/m³ and 6500?mg/m³ for 13 weeks. Levels of malondialdehyde, glutathione, glutathione peroxidase and superoxide dismutase were assayed. Meanwhile, the ultrastructure of hepatic tissues was observed and cell apoptosis was detected via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Furthermore, we investigated the expression levels of mRNA and protein of bax, bcl-2, cytochrome c, caspase-9 and caspase-3 in rat liver tissues. Compared with control group, the malondialdehyde levels were significantly elevated while glutathione levels and activities of glutathione peroxidase and superoxide dismutase were decreased, respectively. The mitochondria of liver appeared swollen with vacuolar structure and loss of cristae in 6500?mg/m³ ethylbenzene-treated group, and ethylbenzene induced a significant increase in the percentage of apoptotic cells as compared to the control group. In addition, enhanced mRNA and protein expression levels of all measured genes were observed in ethylbenzene-treated groups except the decreased bcl-2 expression levels. Our results indicated that ethylbenzene may induce oxidative damage and apoptosis in rat liver. Mitochondrial-mediated pathway was involved in the apoptosis process.     

Prediction of enzyme activity with neural network models based on electronic and geometrical features of substrates

BackgroundArtificial Neural Networks (ANNs) are introduced as robust and versatile tools in quantitative structure-activity relationship (QSAR) modeling. Their application to the modeling of enzyme reactivity is discussed, along with methodological issues. Methods of input variable selection, optimization of network internal structure, data set division and model validation are discussed. The application of ANNs in the modeling of enzyme activity over the last 20 years is briefly recounted.MethodsThe discussed methodology is exemplified by the case of ethylbenzene dehydrogenase (EBDH). Intelligent Problem Solver and genetic algorithms are applied for input vector selection, whereas k-means clustering is used to partition the data into training and test cases.ResultsThe obtained models exhibit high correlation between the predicted and experimental values (R² > 0.9). Sensitivity analyses and study of the response curves are used as tools for the physicochemical interpretation of the models in terms of the EBDH reaction mechanism.ConclusionsNeural networks are shown to be a versatile tool for the construction of robust QSAR models that can be applied to a range of aspects important in drug design and the prediction of biological activity.