生物合成磁铁矿及其应用

本文介绍了国外在生物合成磁性矿物及其应用方面的研究成果，内容包括生物合成Ｆｅ３Ｏ４的特性、研究生物合成磁铁矿的科学意义及细菌磁铁矿在高技术领域中的应用．     

基于Dexter的协同超媒体系统设计

论述了基于Ｄｅｘｔｅｒ超文本标准模型的协同超媒体系统的通用体系结构设计中的问题。该结构包括开发与Ｄｅｘｔｅｒ兼容的超媒体系统的通用框架。其中的编辑进程、客户进程和ＯＯＤＢ服务器进程分别对应于Ｄｅｘｔｅｒ模型的各个层。ＯＯＤＢ提供了灵活的锁定和通告机制，这些机制使得ＯＯＤＢ更为通用且可独立于基于Ｄｅｘｔｅｒ的进程和数据模型而有所变化和扩展。文章最后给出了一些协同系统使用的典型例子。     

贵州植物园珍稀濒危蕨类植物

本文介绍引种自贵州各地及我国华中、华东和华东的贵州植物园内的珍稀濒危蕨类植物。除列表表示来源、现状等情况外，还对桫椤Ａｌｓｐｈｉｌａ ｓｐｉｎｕｌｏｓａ （Ｈｏｏｋ）Ｔｒｙｏｎ，扇蕨Ｎｅｏｃｈｅｉｒｏｐｔｅｒｉｓ ｐｌａｍａｔｏｐｅｄａｔａ （Ｂａｋ．）Ｃｈｓｉｓｔ，宽叶水韭Ｉｓｏｅｔｅｓ ｊａｐｏｎｉｃａ Ａ．Ｂｒ．，中华水韭Ｉ．ｓｉｎｅｎｓｉｓ Ｐａｌｍｅｒ和截基盾蕨Ｎｅｏｌｅｐｉｓｏｒｕｓ     

Bi_2DyFe_5O_（12－x）薄膜的磁性及MOSSBAUER研究

利用Ｘ－射线衍射，磁性测量及测量等手段研究了溅射态氧化物薄膜Ｂｉ＿２ＤｙＦｅ＿５Ｏ＿（１２－ｘ）的结构，磁性及晶化过程，得到了一些新的结果。     

固定化酶流动注射化学发光法测定葡萄糖

本文制备了高活性长寿命的固定葡萄氧化酶，并用于流动流射化学发光分析法测定人血清中葡萄糖的含量，结果令人满意，方法的线性范围为０．４－１００μｍ．ｍＬ＾－１，检出限可达０．０８μｇ．ｍＬ＾－１，检出限可达０．０８μｇ．ｍＬ＾－１，在测量条件下血清中的共存物质均不产生干扰，取样量数微升，一分钟内就可得出结果。     

脉冲磁场对种子生物效应的研究

本文报道多种频率的脉冲磁场作用于蔬菜种子，提高种子活力，进而研究脉冲磁场的生物效应实验表明：脉冲磁场强度在一定的阈值内，作用一定的时间，种子活力将提高，出现正的生物效应（刺激效应），而超过这一阈值范围．种子将出现负的生物效应（抑制效应）．     

邦德功指数试验的模型化及仿真

本文用数学模型方法和计算机仿真技术,系统地分析、研究了测定邦德功指数的可磨度试验,成功地提出了一种快速、准确的测定邦德功指数的计算机仿真方法。六种标准矿样的对比实验结果表明:这些矿样的功指数的计算机仿真值与实测值非常接近,由计算机打印出的仿真过程与实际可磨度试验过程是一致的。在计算机上完成测定功指数的仿真过程一般为2分钟左右,它不仅提高了测定精度,而且大大减少了测定功指数的试验时间和工作量。     

Catalysis of protein folding by prolyl isomerase

Rates of protein folding reactions vary considerably. Some denatured proteins regain the native conformation within milliseconds or seconds, whereas others refold very slowly in the time range of minutes or hours. Varying folding rates are observed not only for different proteins, but can also be detected for single polypeptide species. This originates from the co-existence of fast- and slow-folding forms of the unfolded protein, which regain the native state with different rates. The proline hypothesis provides a plausible explanation for this heterogeneity. It assumes that the slow-folding molecules possess non-native isomers of peptide bonds between proline and another residue, and that crucial steps in the refolding of the slow-folding molecules are limited in rate by the slow reisomerization of such incorrect proline peptide bonds. Recently the enzyme peptidyl-prolyl cis-trans isomerase (PPIase) was discovered and purified from pig kidney. It catalyses efficiently the cis in equilibrium trans isomerization of proline imidic peptide bonds in oligopeptides. Here we show that it also catalyses slow steps in the refolding of a number of proteins of which fast- and slow-folding species have been observed and where it was suggested that proline isomerization was involved in slow refolding. The efficiency of catalysis depends on the accessibility for the isomerase of the particular proline peptide bonds in the refolding protein chain.     

Glioma cell activation by Alzheimer's peptide Abeta1-42, alpha1-antichymotrypsin,and their mixture

We compared the effects ofAlzheimer's peptide (Abeta1-42), a,-antichymotrypsin (ACT) and an ACT/Abeta1-42 mixture on human glioma DK-MG cells. The solution of Abeta (5 microM) formed by 2-h incubation at room temperature induced tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 levels by 55 and 45%, respectively, and increased gelatinase B activity by 67%, while exposure of cells to the ACT/Abeta1-42 mixture (1:10 molar ratio ACT: Abeta1-42) under the same experimental conditions showed no effect on IL-6 levels or gelatinase B activity, but strongly induced TNF-alpha (by 190%), compared to the controls. Stimulation of the cells with Abeta1-42 alone, but not with ACT, increased by about 20% low-density lipoprotein (LDL) uptake and mRNA levels for LDL receptor and HMG-CoA reductase, while the ACT/Abeta1-42 mixture significantly increased LDL uptake (by 50%), up-regulated mRNA levels for LDL receptor and HMG-CoA reductase by 48 and 63%, respectively, and increased lipid accumulation by about 20-fold. These data suggest a possible new role for Abeta in Alzheimer's disease through its interaction with the inflammatory reactant, ACT.