Arabinogalactan as a carrier for contrast agent in magnetic resonance imaging

Arabinogalactan-Gd-DTPA was synthesized by the reaction of diethylenetriaminepenta-acetic acid (DTPA) bisanhydride with polysaccharide in dry DMSO and characterized by FTIR, elemental analysis and ICP-AES. Its stability was investigated by competition with Ca2+, EDTA, DTPA. The t(1)-relaxivity is 8.06 mmol(-1) . L . s(-1) in D2O, 8.48 mmol(-1) . L . s(-1) in 0.725 mmol . L-1 BSA, respectively. t(1)-weighted MR imaging of rat kidney and liver showed a remarkable enhancement post injection of Arabinogalactan-Gd-DTPA. The results indicate that the arabinogalactan-Gd-DTPA is a potential contrast agent for MRI.

以阿拉伯半乳聚糖为载体的磁共振成像造影剂的研究

合成了阿拉伯半乳聚糖修饰的 DTPA钆配合物 ,用红外光谱、元素分析、 ICP-AES等手段进行了表征 ,用竞争性方法研究了其在水溶液中的稳定性 ,测试了其在水中及 BSA溶液中的弛豫性能 ,并进行了体内成像实验 .结果表明 ,其弛豫效率是目前临床所用造影剂 Gd-DTPA的 1 .5～ 2 .0倍 ,对肝脏和肾脏 MRI信号具有良好的增强效果 ,是比较好的潜在磁共振成像造影剂

Electrochemical behavior of 3,4-dihydroxybenzoic acid in self-assembled monolayer electrode system

The self-assembled monolayer of cystamine was prepared on gold electrode and 3,4-dihydroxybenzoic acid (DHBA) was electrochemically deposited on cystamine surface as a functional group by electrostatic adsorption, namely, molecular deposition. It shows that the MD/SAM structure has a higher stability, and E-1/2 of the DBAH in MD/SAM shifts more negative than that of on naked gold electrode, The n-decanethiol was also used to fill defects in MD/SAM, it results in much better cyclic voltermmetric behavior.

3,4-二羟基苯甲酸在自组装结构中的电化学行为

电极与有确定取向的电活性基团之间的电子传递是电化学领域的研究热点．利用二维有序薄膜固定电活性官能团是一个成熟的方法［１］，主要包括ＬＢ技术和自组装技术，这两者都存在着样品合成困难的问题．近年来，通过表面逐层反应来固定电活性官能团已有研究，但是反应过程…

Cure processing modeling and cure cycle simulation of epoxy-terminated poly(phenylene ether ketone) .4. Cure cycle simulation

Epoxy-terminated poly(phenylene ether ketone) (E-PEK) developed in this Institute is a candidate matrix resin for polymer composites as structural materials. Cure cycles for this reaction system were simulated according to the previously established processing model. It is found that for the E-PEK system, the curing process is best completed by a stepwise cure cycle comprising two isothermal processes at different temperatures, T-1 and T-2. The cure cycles over a wide range of processing parameters simulated, based on the established processing model, indicate that the processing window is width-adjustable. Analysis of the mechanical properties of the composite sheets showed that the simulated cure cycles are acceptable and reliable. (C) 1997 John Wiley & Sons, Inc.

Miscibility and crystallization behaviour of poly(ether ether ketone)/polyimide blends

The miscibility and crystallization behaviour of the blends of poly(ether ether ketone) (PEEK) with two thermoplastic polyimides (PI), PEI-E and YS-30, prepared by solution blending were studied by the use of small-angle X-ray scattering (SAXS), differential scanning calorimetry (d.s.c.) and polarizing microscopy techniques. The results obtained show that PEEK/YS-30 is miscible, while PEEK/PEI-E is partially miscible only in the composition range with PEI-E content up to 20 wt%. The crystallization behaviour of PEEK in PEEK/PI blends depends on the crystallization condition of the blend sample as well as the chemical structure and the content of the PI added. Our SAXS results indicate that the segregation of PI molecular chains during crystallization of PEEK chains in the blends is interfibrillar for PEEK/PEI-E blends, but interlamellar for PEEK/YS-30 blends. The compatibility and the crystallization behaviour are discussed in terms of charge transfer interaction between PI and PI molecules and between PI and PEEK molecules.

Myroides profundi sp nov., isolated from deep-sea sediment of the southern Okinawa Trough

A Gram-negative, nonmotile, aerobic and oxidase- and catalase-positive bacterium,, designated D25(T), was isolated from the deep-sea sediments of the southern Okinawa Trough area. Phylogenetic analyses of 16S rRNA gene sequences showed that strain D25(T), fell within the genus Myroides, with 99.2%, 96.0% and 93.4% sequence similarities to the only three recognized species of Myroides. However, the DNA-DNA similarity Value between strain D25(T) and its nearest neighbour Myroides odoratimimus JCM 7460(T) was only 49.9% ( < 70%). Several phenotypic properties could be used to distinguish strain D25(T) from other Myroides species. The main cellular fatty acids of strain D25(T) were iso-C-15:0, iso-C-17:1 omega 9C, iso-C(17:0)3-OH and Summed Feature 3 (comprising C-16:1 omega 7c and/or iso-C(15:0)2-OH). The major respiratory quinone was MK-6. The DNA G+C content was 33.0 mol%. The results of the polyphasic taxonomy analysis suggested that strain D251(T) represents a novel species of the genus Myroides, for which the name Myroides profundi sp. nov. is proposed. The type strain is D25(T) (=CCTCC M 208030(T) = DSM 19823(T)).

一种高智能化的通用自动胶片判读仪

自动通用胶片判读仪是一种高智能化的精密光学测试设备,采用了计算机控制飞点扫描技术、精密光学测量技术、图象跟踪测量与信息处理技术。飞点管分辨率达4096×4096象元,通过光学系统胶片上获得6.55μm高分辨率,飞点扫描方式灵活多样且可随意控制,通用于目前我国靶场所有的电影经纬仪和高速摄影机35mm胶片的数据判读。具有自动判读和半自动判读两种工作模式,自动判读的速度为5帧/秒,自动判读的精度为σ=±0.011mm,半自动判读的精度为σ=±0.009mm,测量数据可以记录、打印和显示。

我国核工业中的遥控技术与机器人技术的应用与开发

为了降低操作人员受照剂量,我国核工厂广泛应用了遥控操作技术,但在检修方面,仍以直接检修为主,本文将对我国核工业中遥控操作与检修技术的现状及包括机器人在内的技术开发与应用设想加以简要说明.

浅议西南岩溶山地的水文生态效应研究

生态水文学是以土壤为联系纽带的生态学和水文学的交叉学科。本文总结了20 世纪90 年代以来生态水文学和西南岩溶山地生态水文学理论研究和实践方面的进展、存在的薄弱环节,在此基础上,论述了岩溶山地生态水文研究的基本内容和原则,提出应加强岩溶山地生态格局和过程的水文学机制研究。本文旨在引起有关人员对岩溶山地生态水文过程研究的重视。

稳定碳同位素示踪农林生态转换系统中土壤有机制裁的迁移和赋存规律

为了探讨土壤有机质在降解过程中的迁移、赋存规律，利用C3、C4植物的δ13C值差异，通过分析土壤的不同粒径组分和比重组分中土壤有机质的δ13C值，表明，粗砂中的土壤有机质年代最新，细粉中的土壤有机质年代最老，有机质在降解过程中，在土壤各粒径组分中的迁移次序是：粗砂→细砂→粗粉→粘土→细粉；土壤重组分中的有机质年代较老，以降解充分、稳定的有机无机复合体为主，轻组分中的有机质含有更多的降解尚不充分、活性较大的有机质.

Cobalt boride catalysts for hydrogen generation from alkaline NaBH4 solution

Cobalt boride precursors were synthesized via chemical reaction of aqueous sodium borohydride with cobalt chloride, and followed by heat-treating at various temperatures. The as-prepared Co-B catalysts were characterized and analyzed by X-ray diffraction (XRD), nitrogen adsorption-desorption and catalytic activity test; and were adopted to help accelerating hydrolysis reaction of NaBH4 alkaline solution. The Co-B catalyst treated at 500 degrees C exhibits the best catalytic activity, and achieves an average H, generation rate of 2970 ml/min/g, which may give a successive H, supply for a 481 W proton exchange membrane fuel cell (PEMFC) at 100% H-2 utilization. (c) 2005 Elsevier B.V. All rights reserved.