Nonisothermal crystallization kinetics of PEO in ethylene terephthalate-ethylene oxide segmented copolymers

The nonisothermal crystallization behavior of Ethylene Terephthalate-Ethylene Oxide (ET-EO) segmented copolymers has been studied with the use of differential scanning calorimetry (DSC). The kinetics of PEO in ET-EO segmented copolymer under nonisothermal crystallization conditions has been analyzed with the Ozawa equation. The results show that there is no agreement with Ozawa's theoretical predictions in the whole crystallization process owing to the constraint of ET segments imposed on the EO segments. A distinct two-crystallization process has been investigated by using the Avrami equation modified by Jeziorny to deal with the nonisothermal crystallization data. The value of the Avrami exponent n is independent of the length of soft segments. However, the crystallization rate is sensitive to the length of soft segments. The longer the soft segments, the faster the crystallization will be.

Gas-phase ion-molecule reactions of neutral C-60 with alkyl methyl ethers under chemical ionization conditions

Gas-phase ion-molecule reactions of buckminsterfullerene (C-60) with the ion systems generated from the self-chemical ionization of alkyl methyl ethers (CH3OR, R = n-C2H5, n-C3H7, n-C4H9) were studied in the ion source of a mass spectrometer. The adduct cation [C60C2H5O](+) and protonated molecule [C60H](+) were observed as the major products. The former adduct ion was produced by the reactions of C-60 with the methoxymethyl ion [CH3OCH2](+), and the latter resulted from the proton transfer reactions from protonated alkyl methyl ethers to C-60 It is suggested that the [3+2] cycloadduct to a 6-6 bond of C-60 (a C-C bond common to two annulated six-membered rings) is the most favorable structure among the probable isomers of [C60C2H5O](+). (C) 1998 John Wiley & Sons, Ltd.

SmC2P1, a C2 domain protein from Scophthalmus maximus that binds bacterial pathogen-infected lymphocytes and reduces bacterial survival

C2 domains are protein structural modules found in many eukaryotic proteins involved in signal transduction, membrane trafficking, and immune defense. Most of the studied C2 domain-containing proteins are multi-domained in structure, in which the C2 domain is an independently folded motif and plays an essential role in calcium-dependent membrane-targeting. Although C2 domains isolated from intact proteins have been studied for biological functions, no study on natural proteins containing C2 domain only has been documented. In this study, we identified a Scophthalmus maximus protein SmC2P1 that is comprised of a single C2 domain and lacks any other apparent domain structures. The deduced amino acid sequence of SmC2P1 contains 129 residues and shares 36-38% identities with the C2 domains of the perforins of several fish species. Like typical C2 domains, SmC2P1 is predicted to organize into eight beta-strands with a Ca2+-binding site located in inter-strand loops. SmC2P1 expression was detected, in deceasing order, in liver, spleen, blood, brain, muscle, kidney, gill, and heart. Experimental challenge of turbot with a bacterial pathogen significantly upregulated SmC2P1 expression in kidney in a time-dependent manner. Recombinant SmC2P1 purified from yeast exhibits no hemolytic activity but binds to pathogen-infected kidney lymphocytes in the presence of calcium. Furthermore, interaction of recombinant SmC2P1 with bacterium-infected lymphocytes reduced bacterial survival. These results indicate that SmC2P1 is a functional protein that is involved in host immune defense against bacterial infection. (C) 2010 Elsevier Ltd. All rights reserved.

壳寡糖及其新型衍生物的制备和抗肿瘤活性初步研究

壳聚糖具有多种生物活性且无毒、无污染，可生物降解，但分子量大，水溶性差，其应用受到很大限制。壳寡糖具有良好的水溶性，其制备方法和应用近年来成为研究的热点。本论文详细研究了酶法和化学法制备壳寡糖的工艺条件，并对酶降解和化学氧化降解的产物进行了比较，结果表明氧化降解的壳寡糖氨基含量有所下降，而酶法降解的产物氨基含量基本没有变化。研究发现在木瓜蛋白酶中加入Vc可以一定程度上降低降解产物的粘度。对几种酶联合降解效果进行了研究，结果表明三种酶的联合降解可得到分子量为1800左右的壳寡糖产物，同时可获得较高产率。 本论文还制备了三种新型壳寡糖衍生物，并研究了壳寡糖和三种衍生物的抗肿瘤活性。通过在壳寡糖上引入胍基乙酸，首次合成了壳寡糖胍基乙酰衍生物(N-2-胍基乙酰-壳寡糖)；引入烟酰氯、烟酰异硫氰酸酯合成了(N-2-烟酰-壳寡糖、N-2-烟酰异硫氰酸酯-壳寡糖)。 通过对BEL•7402肝癌细胞进行了抑制肿瘤活性研究表明：烟酰壳寡糖衍生物的抗肿瘤活性较其他两种衍生物和壳寡糖的活性要好(1mg/ml浓度下抑制率为21.54%)，在较低浓度下有一定的抑制活性（50ug/ml浓度下抑制率为3.57%）。随着浓度的升高，抑制活性也随之提高。烟酰异硫氰酸酯壳寡糖衍生物和胍基乙酰壳寡糖衍生物在低浓度条件下对肿瘤细胞基本没有抑制活性，在高浓度条件下有一定的抑制活性。

Distribution patterns of chlorophyll a in spring and autumn in association with hydrological features in the southern Yellow Sea and northern East China Sea

Two field studies were conducted to measure pigments in the Southern Yellow Sea (SYS) and the northern East China Sea (NECS) in April (spring) and September (autumn) to evaluate the distribution pattern of phytoplankton stock (Chl a concentration) and the impact of hydrological features such as water mass, mixing and tidal front on these patterns. The results indicated that the Chl a concentration was 2.43 +/- 2.64 (Mean +/- SD) mg m(-3) in April (range, 0.35 to 17.02 mg m(-3)) and 1.75 +/- 3.10 mg m(-3) in September (from 0.07 to 36.54 mg m(-3)) in 2003. Additionally, four areas with higher Chl a concentrations were observed in the surface water in April, while two were observed in September, and these areas were located within or near the point at which different water masses converged (temperature front area). The distribution pattern of Chl a was generally consistent between onshore and offshore stations at different depths in April and September. Specifically, higher Chl a concentrations were observed along the coastal line in September, which consisted of a mixing area and a tidal front area, although the distributional pattern of Chl a concentrations varied along transects in April. The maximum Chl a concentration at each station was observed in the surface and subsurface layer (0-10 m) for onshore stations and the thermocline layer (10-30 m) for offshore stations in September, while the greatest concentrations were generally observed in surface and subsurface water (0-10 m) in April. The formation of the Chl a distributional pattern in the SYS and NECS and its relationship with possible influencing factors is also discussed. Although physical forces had a close relationship with Chl a distribution, more data are required to clearly and comprehensively elucidate the spatial pattern dynamics of Chl a in the SYS and NECS.

须花藤的化学成分

采用乙醇提取，硅胶柱层析分离和波谱方法鉴定结构，从须花藤Genianthus laurifolius (Roxb.) Hook. f.地上部分共分离鉴定出8个化合物：羽扇豆醇乙酯（I）、大黄素甲醚（II）、β－谷甾醇（III）、6，23－二烯－5，8－过氧麦角甾－3－醇（IV）、7，8β－epoxysinogenin-α-D-oleandropyranoside(V)、常春藤配基（VI）、3β，23－二羟基乌索－12－烯－28－酸（VII）和胡萝卜甙（VIII）。这些化合物均为首次从该属植物中分离得到。

机器人既需要本能反应也离不开智能行为

发展方向与实施战略研究历来是一切科学的生命线,机器人同样不会产生例外。这些年,虽然机器人对社会的作用已被人们逐渐认识并接受,而且围绕中心决策还取得了一系列重大成就,但其不足也表现得十分明显和一时难以解决。在这种形势下,行为包容理论即迅速掘起且大有完全取代中心决策之势。为探索本领域今后去向,正确寻找突破口,本文在论述智能与本能特性、联系和区别的基础上, 通过分析它们在机器人中的地位与作用,明确了各自拥有的效能与局限,给出了彼此的互助、协同关系, 以及动作基元实现策略。

锡矿山锑矿床热液方解石的Sm-Nd同位素定年

通过对热液成因方解石Sm-Nd同位素体系的研究, 对湘中锡矿山超大型锑矿床的形成时代进行了精确限定. 研究表明, 锡矿山锑矿床形成于晚侏罗世~早白垩世, 早、晚两期的成矿作用时间分别是(155.5±1.1)和(124.1±3.7) Ma. 对该矿床成矿时代的精确厘定, 有助于揭示该区元素Sb的超常富集机制, 为深入认识其矿床成因和成矿机理奠定了基础.

New cocktail functional monomers in making molecule imprinting polymer with high chiral selectivity

in order td produce molecule imprinting polymer (MIP) with high chiral selectivity against N-c-protected amino acid, new cocktail functional monomers acrylamide (AM) + 2-vinylpyridine (2-VP) and AM + methacrylic acid (MAA) were investigated. AM + 2-VP was found to be more efficient in improving the selectivity and resolution of the molecule imprinting polymer.

武警工作倦怠及相关因素分析

Accumulating studies have been conducted on job burnout in the fields of organizational psychology and health psychology, but there are few studies investigating job burnout for people in the Chinese Armed Police Force(CAPF). This thesis explored the antecedents (social comparison, perceived control and perceived organizational support) and outcomes (incumbents’ level of task performance and psychological health) of job burnout, using data collected from 458 teachers (study 1) and 792 officers (470 lower level army cadres,150 commandos and 172 teachers, study 2) in CAPF. Two studies were carried out. The results are as follows: 1. There were significant differences among the three dimensions of job burnout for teachers: reduced accomplishment was rated significantly higher than cynicism and emotional exhaustion. 2. For the emotional exhaustion dimension, special technical soldiers gave the highest ratings and cadres provided the lowest ratings. Besides, special technical soldiers and teachers rated higher on cynicism than cadres did. 3. Perceived control significantly influenced job burnout: the higher the perceived control, the lower the three dimension of job burnout (emotional exhaustion, cynicism and reduced accomplishment). 4. Perceived control exerted impacts on psychological health directly and indirectly: the higher the perceived control, the better psychological health. Moreover, perceived control had significant effects on psychological health through emotional exhaustion: the higher the perceived control, the lower emotional exhaustion and the better psychological health. 5. The higher perceived organizational support, the lower the three dimensions of job burnout; perceived organizational support impacted psychological health through emotional exhaustion: the higher perceived organizational support, the lower emotional exhaustion and the better psychological health. 6. Job burnout exerted significant influence on task performance: the higher reduced accomplishment, the lower task performance rated by participants themselves. Drawing on the above results, measures would be taken in CAPF to enhance perceived control and perceived organizational support, to alleviate burnout and improve task performance and psychological health.