A disposable sensor based on immobilization of acetylcholinesterase to multiwall carbon nanotube modified screen-printed electrode for determination of carbaryl

A simple method has been devised for immobilization of acetylcholinesterase (AChE) covalent bonding to a multiwall carbon nanotube (MWNT)-cross-linked cellulose acetate composite on a screen-printed carbon electrode (SPCE) and a sensitive and disposable amperometric sensor for rapid determination of carbaryl pesticide is proposed. The immobilized enzyme was preserved on this film because of the excellent biocompatibility and non-toxicity of cellulose acetate. Based on the inherent conductive properties of the MWNT, the immobilized AChE had greater affinity for ATCl and excellent catalytic effect in the hydrolysis of ATCl. MWNT improved the interface enzymatic hydrolysis reaction and increased the amperometric response of the sensor. Under optimum conditions, the inhibition of carbaryl on AChE increased linearly with the increasing concentration of carbaryl in two ranges, from 0.01 to 0.5 μg mL⁻¹ and from 2 to 20 μg mL⁻¹, with the correlation coefficients of 0.9985 and 0.9977, respectively. The detection limit was 0.004 μg mL⁻¹ taken as the concentration equivalent to 10% decrease in signal. The sensor showed acceptable stability, accuracy and could be fabricated in batches, thus it is economic and portable. This type of disposable enzyme-based amperometric sensor has extensive application potential in environmental monitoring of pesticides.     

白云鄂博主矿开拓运输工艺转换有关问题的探讨

本文对白云鄂博主矿采场铁公路联合运输向公路运输转换位置是否确定为1638m水平以及运输工艺转换过程中相关问题进行分析论证，提出主矿采场铁路至少可向下延深一个水平，技术上可行，节约运费千万元以上。     

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以甲基二氯硅烷、四甲基四乙烯基环四硅氧烷(DVi4)为原料,采用硅氢加成反应合成了星型聚合物的中问体环硅氧烷核,并用红外光谱和核磁共振谱进行了表征.反应的最佳条件是:采用预先活化、反应温度72℃、催化荆与DVi4的量之比为1.0×10-4,反应转化率可达95%,且选择性很好,产物主要为β-加成产物.     

云台山隧道进口黄土段施工技术

从防排水、边仰坡支护、洞口加固、洞内超前支护、钢拱架锚喷联合支护等方面详细介绍了云台山隧道进口黄土段的施工技术,总结了该隧道的施工效果,强调了黄土隧道施工中防排水超前支护预注浆、施工监控的作用,积累了隧道施工经验.     

东丽湖邻里中心

在承接这个项目之前，我们不知道天津东部还有东丽湖这么一大片保存完好的湿地，夕阳映照着辽阔的水面，芦苇中闪现着轻盈的水鸟。邻里中心——作为这片宝地旁边200hm^2大型低密度社区第一个登台亮相的小组团，对参与其中的所有人来说，既有动人的诱惑，又有切实的压力。     

10MeV中子引起的~（238）U，~（209）Bi，Fe和~9Be的次级中子

１０ＭｅＶ中子引起的￣（２３８）Ｕ，￣（２０９）Ｂｉ，Ｆｅ和￣９Ｂｅ的次级中子双微分截面测量祁步嘉，唐洪庆，周祖英，周陈维，沈冠仁，柯尊建，孙振强，夏海鸿（中国原子能科学研究院核物理所，北京２７５－４６信箱，１０２４１３）次级中子双微分截面是核工程设...     

Site occupations and ordering behaviour of O phase in Ti2AlNb—based intermetallics

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