THIN-LAYER ELECTROCHEMICAL DETECTOR COATED WITH NAFION FILM

Electrochemical detection of the flow system has attracted considerable interest in recent years due to its high sensitivity and selectivity towards electroactive compounds. However, the improvement of sensitivity and selectivity is still a desire for practical application. In this note, a thin-layer electrochemical detector of the

The responsive expression of heat shock protein 22 gene in zhikong scallop Chlamys farreri against a bacterial challenge

HSP22 is a member of a small HSP subfamily contributing to the growth, transformation and apoptosis of the cell as well as acting as a molecular chaperone. In the present study, CfHSP22 cDNA was cloned from Chlamys farreri by the rapid amplification of cDNA ends technique. The full-length cDNA of CfHSP22 was of 1279 bp, consisting of a 5'-terminal untranslated region (5'UTR) of 122 bp, a 3'UTR of 581 bp with a canonical polyadenylation signal sequence AATAAA and a poly( A) tail, and an open reading frame of 576 bp encoding a polypeptide with a molecular mass of 22.21 kDa and a predicted isoelectric point of 9.69. There was an alpha-crystallin domain, a hallmark of the sHSP subfamily, in the C-terminus, and the deduced amino acid sequence of CfHSP22 showed high similarity to previously identified HSP22s. CfHSP22 was constitutively expressed in the haemocyte, muscle, kidney, gonad, gill, heart and hepatopancreas, and the expression level in the hepatopancreas was higher than that in the other tissues. CfHSP22 transcription was up-regulated and reached a maximal level at 12 h after the bacterial challenge, and then declined progressively to the original level at 48 h. These results suggested that CfHSP22 perhaps play a critical role in response to the bacterial challenge in haemocytes of scallop C. farreri.

Intra-habitat heterogeneity of microbial food web structure under the regime of eutrophication and sediment resuspension in the large subtropical shallow Lake Taihu, China

Planktonic microbial community structure and classical food web were investigated in the large shallow eutrophic Lake Taihu (2338 km(2), mean depth 1.9 m) located in subtropical Southeast China. The water column of the lake was sampled biweekly at two sites located 22 km apart over a period of twelve month. Site 1 is under the regime of heavy eutrophication while Site 2 is governed by wind-driven sediment resuspension. Within-lake comparison indicates that phosphorus enrichment resulted in increased abundance of microbial components. However, the coupling between total phosphorus and abundance of microbial components was different between the two sites. Much stronger coupling was observed at Site 1 than at Site 2. The weak coupling at Site 2 was mainly caused by strong sediment resuspension, which limited growth of phytoplankton and, consequently, growth of bacterioplankton and other microbial components. High percentages of attached bacteria, which were strongly correlated with the biomass of phytoplankton, especially Microcystis spp., were found at Site 1 during summer and early autumn, but no such correlation was observed at Site 2. This potentially leads to differences in carbon flow through microbial food web at different locations. Overall, significant heterogeneity of microbial food web structure between the two sites was observed. Site-specific differences in nutrient enrichment (i.e. nitrogen and phosphorus) and sediment resuspension were identified as driving forces of the observed intra-habitat differences in food web structure.

Insecticidal activity of proteinous venom from tentacle of jellyfish Rhopilema esculentum Kishinouye

Insecticidal activity of proteinous venom from tentacle of jellyfish Rhopilema esculentum Kishinouye was determined against three pest species, Stephanitis pyri Fabriciusa, Aphis medicaginis Koch, and Myzus persicae Sulzer. R. esculentum full proteinous venom had different insecticidal activity against S. pyri Fabriciusa, A. niedicaginis Koch, and M. persicae Sulzer. The 48 It LC50 values were 123.1, 581.6, and 716.3 mu g/mL, respectively. Of the three pests, R. esculentuin full proteinous venom had the most potent toxicity against S. pyri Fabriciusa, and the corrected mortality recorded at 48 It was 97.86%. So, S. pyri Fabriciusa could be a potential target pest of R. esculentum full proteinous venom. (c) 2005 Elsevier Ltd. All rights reserved.

黑河上游生态建设的模式与效益

在黑河上游实施的以牛羊育肥、退化草原的植被恢复、人工草地建设为主要内容的生态建设,通过技术集成和试验示范,效果显著.混播一年生草地平均产干草9.6 t•hm2,每公顷约可为400只羊提供冬春季节补饲用草,补饲措施可降低牲畜越冬死亡率50%以上,提高仔畜成活率10%;围栏封育增加草地水源涵养功能,可使土壤含水量提高20%左右.绵羊育肥可使示范区农牧民人均增加收入300元.农业结构已经呈现明显的"山地-河谷-绿洲"一体化发展的系统耦合新结构,系统耦合的效应对植被的保护起到了很好的作用.

云贵高原湖泊CO2的地球化学变化及其大气CO2源汇效应

国家自然科学基金项目(批准号：49903007和40073032)和中国科学院知识创新工程项目(批准号：KZCX2—105)资助

中国西南喀斯特湖泊硫酸盐来源的硫同位素示踪研究

硫是导致酸沉降的主要大气污染物之一,主要来源于重工业污染和矿物燃料利用过程中的排放.处于中国西南地区的贵阳市,其酸雨污染问题一直很严重,这是由于该地区分布有较多的燃煤型火力发电厂和冬季居民的取暖用煤释放,而该地区煤中S的含量可高达20 mg/L.……硫是导致酸沉降的主要大气污染物之一,主要来源于重工业污染和矿物燃料利用过程中的排放.处于中国西南地区的贵阳市,其酸雨污染问题一直很严重,这是由于该地区分布有较多的燃煤型火力发电厂和冬季居民的取暖用煤释放,而该地区煤中S的含量可高达20 mg/L.

热液矿床中含钙矿物的Sm—Nd同位素定年

Sm、Nd的离子半径相似、化学性质很相近，母体衰变形成的子体易在矿物晶格中保存下来，故矿物或岩石中的Sm—Nd同位素体系易保持封闭，具有较强的抗风化、抗蚀变能力，是一种有效的定年工具。但长期以来，Sm—Nd同位素体系主要用于前寒武纪地质年代学研究，研究对象主要限于陨石、月球岩石、古老的基性、超基性岩和前寒武纪老地层等。近年的研究表明，热液矿床中一些含钙矿物，其REE含量较高，Sm／Nd分馏明显，是很有潜力的Sm—Nd同位素定年对象，能对矿床的成矿时间进行精确制约。本文对萤石、白钨矿、方解石、电气石等常见热液含钙矿物的Sm—Nd同位素研究现状进行归纳总结，并对该方法在中国热液矿床中进一步的应用前景进行了展望，以期促进Sm—Nd同位素成矿年代学在我国的推广和应用.

云南大红山层状铜矿床地球化学及成矿机制研究

云南省大红山铁铜矿床位于康滇地轴南端西缘，介于红河深断裂与绿汁江深断裂所夹持的滇中台坳内，赋存于中元古代大红山群海相火山喷流-沉积岩系中，是我国典型的火山岩型块状硫化物（VHMS）矿床之一。该矿床包括一系列与火山喷发-岩浆侵入活动相关但成因有一定差别的矿床，被统称为“大红山式”铁铜矿床。该矿床经济价值巨大，铁、铜储量均达超大型矿床规模，但其研究程度较低，多停留在矿区地质特征层面上，地球化学研究较为薄弱。本次工作系统地研究了大红山层状铜矿床中各类岩石的岩相学特征，对特征矿物做了电子探针定性和定量分析，挑选火山质岩石中锆石做定年分析，系统分析了岩石的主量元素和微量元素，测定了硫化物的硫和铅同位素，并选取了与富集型硫化物相关的石英脉矿物和碳酸盐矿物分别做流体包裹体和碳、氧同位素研究。论文取得的主要认识如下： 1．红山群曼岗河组火山喷流-沉积年代约为1687±8Ma，即形成于早-中元古代，因此不可能遭受如前人所说的吕梁运动改造作用。在700 ~ 800Ma左右，即晋宁运动期本区遭受了强烈的变质变形以及流体蚀变改造作用。 2．层状铜矿中岩石类型主要为黑云母片岩、白云石钠长石岩和白云石大理岩。黑云母片岩中主要矿物为黑云母、钠长石、铁白云石和石榴子石；白云石钠长石岩中主要矿物为钠长石、铁白云石、石榴子石及少量的黑云母；白云石大理岩中主要矿物为铁白云石，含少量的钠长石和黑云母。岩石原岩恢复表明，三类岩石原岩为火山物质、泥质沉积物和喷流热水沉积混合组成，其中黑云母片岩以泥质为主，包含火山质物质和喷流热水沉积物质；白云石钠长石岩以火山物质和喷流热水为主，含少量的泥质；白云石大理岩以热水喷流沉积为主。 3．本区至少遭受过三期变质作用：区域高温变质作用、流体蚀变改造作用和变形变质作用。区域高温变质作用变质温度最高可达可达660℃，主要集中在600 ~ 630℃之间，形成压力约为4.9 ~ 5.0Kbar。三期变质改造使原岩发生了绿帘-角闪岩相的变质作用，变质过程中，稀土元素（特别是轻稀土元素）和部分高场强元素发生了迁移；流体蚀变改造富集了早期的贫铜矿胚，使之形成工业矿床。 4．硫化物硫同位素研究显示，其δ34S值为-0.6 ~ +10.9‰，主要集中在+5.0 ~ +10.9‰之间。这一组成表明富集型硫化物大体继承了早期硫化物硫源特征，并在改造过程中富集重硫。早期硫化物硫源主要来自岩浆硫和海水无机还原硫。硫化物铅同位素范围为：206Pb/204Pb＝ 18.985 ~ 23.318，均值为21.222；207Pb/204Pb＝15.581 ~ 15.904，均值为15.747；208Pb/204Pb＝39.803 ~ 45.652，均值为42.540。显然，本区硫化物具有极高含量的放射性成因铅，部分放射性成因铅含量稍低的样品与前人所圈定的改造型矿床的硫化物铅同位素范围较为吻合。分析认为，本区硫化物铅同位素代表了两种不同铅源的混合，即早期硫化物的普通铅和围岩中的放射性成因铅。硫铅同位素示踪以及矿相学研究表明，本区早期铜质来源于海底火山喷流-沉积，而晚期富集型铜矿铜质继承了早期铜质，同时也不排除晚期流体中所带来的铜质。 5．流体包裹体研究表明，本区改造型流体中包括三种流体体系：①中-低盐度H2O-NaCl±KCl±FeCl3 ±CaCl2流体，盐度范围为0.53 ~ 24.59 % NaCl equiv.，密度为0.80 ~ 1.16 g/cm3；②高盐度高密度H2O-NaCl±CaCl2流体，盐度为31.2 ~ >59.76% NaCl equiv，密度为1.14 ~ 1.45 g/cm3；③纯液相CO2流体，流体密度为0.77 ~ 1.09 g/cm3。流体包裹体均一温度在100 ~ 456℃之间，主要集中在150 ~ 260℃和260 ~ 456℃两个温度区间。方解石碳、氧同位素范围分别为-5.6 ~ -3.1‰和12.4 ~ 15.5‰。综合分析表明，流体主要来自海底下伏岩浆房的出溶或喷流的高温高盐度流体，部分与海水混合。流体在热液改造过程中活化富集了早期硫化物，经过短距搬运而沉积形成了晚期富集型硫化物。 6．本次研究确定该矿床的成矿机制为：早-中元古代，本区的陆内裂谷作用为火山喷发提供了构造条件，海底火山喷流-沉积形成了早期的贫铜矿胚。元古代末期，本区遭受了强烈的区域变质、变形和流体蚀变改造作用，使原先的贫铜矿胚得到活化富集，形成了工业矿床。

Preparation and characterization of Pd-Ag alloy composite membrane with magnetron sputtering

A Pd-Ag (24 wt%) alloy composite membrane was prepared by the magnetron sputtering. A gamma-Al2O3 membrane was synthesized by the sol-gel method and used as substrate of the Pd-Ag alloy film. The process parameters of the magnetron sputtering were optimized as a function of the compactness of the Pd-Ag alloy film. The best membrane with a thickness of 1 mu m was produced with a sputtering pressure of 2.7 Pa and a substrate temperature of 400 degrees C. The membrane had an H-2/N-2 permselectivity of 51.5-1000 and an H-2 permeation rate of 0.036-1.17 x 10(-5)cm(3)/cm(2).s. Pa, depending on operating conditions.