文冠果壳提取物对β-淀粉样蛋白致动物学习记忆障碍的改善作用

目的研究文冠果壳乙醇提取物对动物学习记忆障碍的改善作用并探讨其可能的作用机制。方法采用水迷宫法、避暗法测定小鼠的学习记忆能力;用Y迷宫法及Morris水迷宫法测试大鼠的学习记忆能力,显微镜下观察海马组织形态学改变。结果文冠果壳乙醇提取物显著减少侧脑室注射β-淀粉样蛋白(25-35)(Aβ(25-35))致记忆障碍小鼠水迷宫实验的逃避潜伏期和避暗实验的错误次数,延长避暗潜伏期;文冠果壳乙醇提取物显著提高D-半乳糖合用Aβ(25-35)致记忆障碍大鼠Y迷宫测试中正确反应率,显著缩短Morris水迷宫测试中的潜伏期及游泳路程;抑制海马神经元的变性及脱落。结论文冠果壳乙醇提取物对Aβ(25-35)致鼠学习记忆障碍有显著的改善作用,其作用机制可能与对抗Aβ(25-35)的毒性有关。

中国陆地生态信息空间化技术研究(Ⅲ):温度、降水等气候要素

利用国家气象局722个气象台站1971～2000年的气象资料,采用三维二次趋势面分析与空间插值相结合等方法,在ArcGIS平台上对气温、降水、空气湿度等气候要素进行空间化,生成国家尺度的1km×1km栅格各种要素气候图180多幅。经检验,平均绝对误差,平均气温和平均最高、最低气温为0.5℃左右,极端最高气温为1℃左右,极端最低气温为1.5℃左右,平均风速为0.4m·min-1;而平均相对误差,≥0℃、5℃、10℃、15℃的积温和平均相对湿度多在5%以下,降水量和饱和差在10%左右;其空间化的精度基本上达到

Impact of cloudiness on net ecosystem exchange of carbon dioxide in different types of forest ecosystems in China

Asia 3 Foresight Program [30721140307]; National Key Research and Development Program [2010CB833500]; National Natural Science Foundation of China [30590381, 30900198];

Interactions Between Exogenous Rare Earth Elements and Phosphorus Leaching in Packed Soil Columns

Through leaching experiments and simulated rainfall experiments, characteristics of vertical leaching of exogenous rare earth elements (REEs) and phosphorus (P) and their losses with surface runoff during simulated rainfall in different types of soils (terra nera soil, cinnamon soil, red soil, loess soil, and purple soil) were investigated. Results of the leaching experiments showed that vertical transports of REEs and P were relatively low, with transport depths less than 6 cm. The vertical leaching rates of REEs and P in the different soils followed the order of purple soil > terra nera soil > red soil > cinnamon soil > loess soil. Results of the simulated rainfall experiments (83 mm h(-1)) revealed that more than 92% of REEs and P transported with soil particles in runoff. The loss rates of REEs and P in surface runoff in the different soil types were in the order of loess soil > terra nera soil > cinnamon soil > red soil > purple soil. The total amounts of losses of REEs and P in runoff were significantly correlated.

Fabrication and electrochemical characterization of electrostatic assembly of polyelectrolyte-functionalized ionic liquid and Prussian blue ultrathin films

Polyelectrolyte-functionalized ionic liquid (PFIL) and Prussian blue (PB) nanoparticles were used to fabricate ultrathin films on the ITO substrate through electrostatic layer-by-layer assembly method. Multilayer growth was examined by UV-vis spectroscopy and cyclic voltammetry. The resulting ITO/(PFIL/PB)n electrode showed two couples of well-defined redox peaks and good electrocatalytical activity towards the reduction of hydrogen peroxide.

不同时间内家兔尿液中乌头碱代谢产物的研究

首次采用LC/ESI-MSn方法对乌头碱灌胃给药后不同时间内家兔尿液中的乌头碱代谢产物进对比研究。经与空白尿样对照发现,在0~4h和4~8h两个时间段,家兔尿液中除乌头碱(AC)原形外,均含有相同的代谢产物,但相对含量差别很大。通过总离子流色谱图(TIC)可以发现3个主要代谢产物(M1,M2,M4)。分别测定了各代谢产物的准分子离子及其各级碎片离子,与AC在ESI-MSn条件下的质谱碎裂规律相比较,并参考AC体内代谢文献,推断尿液中的主要代谢产物M1为16-O-去甲基乌头碱;M2和M4的m/z均为616,为同分异构体,结构还需要进一步的确认。

Eu~(3+)和Ho~(3+)对乙醇在Pt-TiO_2/C电极上氧化的助催化作用

报道了用循环伏安法研究Eu3+和Ho3+吸附的碳载Pt-TiO2(pt-TiO2/C)催化剂对乙醇电化学氧化的助催化作用.发现无论在中性溶液中还是在酸性溶液中,当Pt-TiO2/C催化剂吸附Eu3+或Ho3+后,都可以使乙醇的电催化氧化电流密度明显增加,其原因主要是Eu3+或Ho3+都能促进吸附的CO的电氧化.

Solvent-induced novel morphologies in diblock copolymer blend thin films

We report the morphology and phase behaviors of blend thin films containing two poly styrene-b-poly (methyl methacrylate) (PS-b-PMMA) diblock copolymers with different blending compositions induced by a selective solvent for the PMMA block, which were studied by transmission electron microscopy (TEM). The neat asymmetric PS-b-PMMA diblock copolymers employed in this study, respectively coded as a(1) and a(2), have similar molecular weights but different volume fractions of PS block (f(PS) = 0.273 and 0.722). Another symmetric PS-b-PMMA diblock copolymer, coded as s, which has a PS block length similar to that of a(1), was also used. For the asymmetric a(1)/a(2) blend thin films, circular multilayered structures were formed. For the asymmetric a(1)/symmetric s blend thin films, inverted phases with PMMA as the dispersed domains were observed, when the weight fraction of s was less than 50%. The origins of the morphology formation in the blend thin films via solvent treatment are discussed. Combined with the theoretical prediction by Birshtein et al. (Polymer 1992, 33, 2750), we interpret the formation of these special microstructures as due to the packing frustration induced by the difference in block lengths and the preferential interactions between the solvent and PMMA block.

Tuning the saturated red emission: synthesis, electrochemistry and photophysics of 2-arylquinoline based iridium(III) complexes and their application in OLEDs

A series of novel iridium(III) complexes with two 2-arylquinoline derivatives as cyclometalated ligands and one monoanionic ligand, such as acetylacetonate (acac), N,N'-diethyldithiocarbamate (Et(2)dtc) and O,O'-diethyldithiophosphate (Et(2)dtp), as ancillary ligands have been synthesized and structurally characterized by H-1 NMR, MS and elemental analysis (EA). The cyclic voltammetry, absorption, emission and electroluminescence properties of these complexes were systematically investigated. Through extending pi-conjugation, introducing electron-donating groups in the ligand frame, or changing the ancillary ligands, the HOMO energy levels of the iridium(III) complexes can be tuned, while their LUMO levels remain little affected; in consequence, the emission wavelengths of the iridium(III) complexes can be tuned in the range 606-653 nm. The highly efficient organic light-emitting diodes (OLEDs) with saturated red emission have been demonstrated. A maximum current efficiency of 10.79 cd A(-1), at a current density of 0.74 mA cm(-2), with an emission wavelength of 616 nm and Commisioon Internationale de L'Eclairage (CIE) coordinates of (0.65, 0.35), which are very close to the National Television System Comittee (NSTC) standard red emission, have been achieved when using complex (DPQ)(2)Ir(acac) as a phosphor dopant.

蓝紫色ZnO-Al_2O_3-SiO_2长余辉陶瓷

通过高温固相法首次合成并报道了兰紫色ZnO Al2O3 SiO2长余辉陶瓷,系统地研究了其发光和缺陷性质。在强度0.6mW·cm-2,主峰254nm的UVP紫外灯下激发15min,然后关闭激发源,样品发射兰紫色长余辉。撤去激发源以后5s,余辉初始强度为230mcd·m-2,色坐标为(0.1292,0.0984)。暗视场中,8h以后余辉仍然肉眼可辨。样品的紫外可见发射和不同时间的余辉发射光谱显示:荧光发射位于390nm,来源于基质的自致发光;而余辉有两个发射峰,主峰位于390nm,肩峰位于520nm。这表明样品中存在两种余辉发射中心。由余辉衰减曲线可以看出,这两种余辉发光都由一个快过程和一个慢过程组成。其中,慢过程决定了材料的长余辉时间。从时间依赖的余辉强度倒数曲线可以看出,余辉强度与时间成反比,这表明余辉发光的机理为电子空穴复合过程。热释光谱显示:样品分别在92和250℃附近出现两个宽的热释峰,说明材料中至少存在两种具有不同陷阱深度的电子或空穴缺陷中心。

稀土基汽车尾气催化剂的研究 Ⅱ:稀土助剂对催化活性的影响

利用浸渍法制备含Ce-La稀土助剂改性的Pt-Rh三效催化剂,采用多种表征手段和高温抗硫水热老化实验,考察Ce-La稀土对Al2O3载体的热稳定性和催化剂活性的影响。结果表明:稀土La2O3的添加主要改善载体Al2O3的高温高比表面性能;CeO2的引入明显提高了CO和NO的催化转化活性,但对HC的转化几乎无影响;CeO2的添加也促进了催化剂的抗硫水热老化性能,并显著拓宽催化剂的三效窗口。主要归因于CeO2的添加促进了催化剂上CO、HC和NO间的相互作用以及CeO2所特有的储氧功能.

Crystallization kinetics of narrow molecular weight distribution metallocene short-chain-branched polyethylene

Isothermal and non-isothermal crystallization kinetics of three metallocene-catalysed short-chain-branched polyethylene (SCBPE) fractions with different degree of branching were investigated by using differential scanning calorimetry (DSC). Narrow molecular weight fractions (M-w = 20,000 and M-w/M-n < 1.15) are used and the degree of branching (CH3 per 1000C) are 1.6, 10.4, 40 respectively. The regime I - II transition temperature are 119.8C, 115.9 degreesC, 113.3 degreesC with the decreasing of degree of branching. Increasing the branch content decreases the rate of secondary nucleation, i,relative to the rate of surface spreading and so increases the range of supercooling over which regime I exists. The rate of bulk crystallization for both isothermal and non-isothermal crystallization decreases with the increasing of degree of branching. Both Ozawa Equation and Kissinger Equation are invalid for non-isothermal crystallization kinetics of SCBPE fractions,that means the effects of the branched chain on crystallization process are more complex than expected.

窄分子量分布茂金属短链支化聚乙烯结晶动力学

本工作用DSC方法对三种不同支化度的茂金属短链支化聚乙烯的等温、非等温结晶行为进行了研究 .样品为乙烯和己烯 1的共聚物 ,短支链主要为正丁基 ,分子量Mw =2 0 ,0 0 0 ,Mw/Mn<1 15 ,支化度 (每10 0 0C中CH3 数目 )分别为 1 6、10 4、40 .实验结果表明 ,茂金属短链支化聚乙烯结晶方式Ⅰ Ⅱ转变温度随支化度增加而降低 ,分别为 119 8℃、115 9℃、113 3℃ ;同时支链的存在降低了二次成核速率 ,增大了方式Ⅰ的结晶范围 ,总的结晶速度随支化度增大而减小