Spatially-confined crystallization of poly(vinylidene fluoride)

Nanometre-sized poly(vinylidene fluoride) (PVDF) particle domains in a confined space were obtained by blending PVDF with excess poly(methyl methacrylate) (PMMA). When these particles were small enough they showed beta -form structure, which was different from the structure of bigger particles or PVDF bulk. However, the beta -form was thermodynamically metastable because it could eventually be transformed to a more stable phase by annealing at a certain temperature. Larger particle domains were of identical phase to the bulk, indicating that small size favours the formation of the beta -form. (C) 2000 Society of Chemical Industry.

Effects of molecular weight and interaction parameter on the glass transition temperature of polystyrene mixtures and its blends with polystyrene/poly(2,6-dimethyl-p-phenylene oxide)

The glass transition temperature (T-g) of mixtures of polystyrene (PS) with different molecular weight and of blends of poly(2,6-dimethyl-p-phenylene oxide) (PPO) and polystyrene with different molecular weight (DMWPS) was studied by a DSC method. For the whole range of composition, the curves of T-g vs composition obtained by experiment were compared with predictions from the Fox, Gordon-Taylor, Couchman and Lu-Weiss, equations. It was found that the experimental results were not in agreement with those from the Fox, Gordon-TayIor and Couchman equations for the binary mixtures of DMWPS, where the interaction parameter chi was approximately zero. However, for the blends PPO/DMWPS (chi < 0), with an increase of molecular weight of PS, it was shown that the experimental results fitted well with those obtained from the Couchman, Gordon-Taylor and Fox equations, respectively. Furthermore, the Gordon-Taylor equation was nearly identical to the Lu-Weiss equation when \chi\ was not very large. Further, the dependence of the change of heat capacity associated with the glass transition (Delta C-p) on the molecular weight of PS was investigated and an empirical equation was presented. (C) 1997 Elsevier Science Ltd.

STRUCTURE OF THIAMINE BROMIDE SESQUIHYDRATE

3-[(4-Amino-2-methyl-5-pyrimidinyl)-methyl]-5-hydroxyethyl-4-methylthiazolium bromide sesquihydrate, C12H17N4OS+.Br-.1.5H2O, M(r) = 372.28, monoclinic, P2(1)/a, a = 11.676 (2), b = 24.819(7), c = 12.344 (3) angstrom, beta = 113.74(2)-degrees, V= 3274 (1) angstrom3 , Z = 8, D(x) = 1.51 g cm-3 (Mo Kalpha) = 0.71069 angstrom, mu = 26.2 cm-1, F(000) = 1528, T 293 K, R = 0.062 for 2720 observed reflections. Both the independent thiamine molecules A and B in the asymmetric unit adopt the common F conformation. A bromide anion is held by four neighbouring thiamine molecules through C(2)-H...Br hydrogen bonds and Br ... thiazolium-ring electrostatic interactions. Another bromide anion (or a water molecule) bridges the pyrimidine and thiazolium moieties of molecule A (or B) through a hydrogen bond with the amino group and an electrostatic interaction with the thiazolium ring.

一种简易长光程可见紫外、圆二色薄层光谱电化学池

设计了一种简易实用的长光程薄层光谱电化学池,该池以10mm石英比色槽为光学窗,2块5×10×50mm的聚四氟乙烯块为电极支承体,玻碳片为工作电极,且薄层厚度可调。以K_3Fe(CN)_6和L-酪氨酸为工作体系进行光谱和电化学实验表明,该池具有良好的薄层电化学特征。对于水溶液,在大于220nm波长内给出良好的光谱和较快的光谱电化学响应,可方便地用于圆二色谱-电化学研究。

Involvement of p90 ribosomal S6 kinase in termination of cell cycle arrest during development of Artemia-encysted embryos

Artemia has evolved a unique developmental pattern of encysted embryos to cope with various environmental threats. Cell divisions totally cease during the preemergence developmental stage from gastrula to prenauplius. The molecular mechanism of this, however, remains unknown. Our study focuses on the involvement of p90 ribosomal S6 kinase (RSK), a family of serine/threonine kinase-mediating signal transduction downstream of mitogen-activated protein kinase cascades, in the termination of cell cycle arrest during the post-embryonic development of Artemia-encysted gastrula. With immunochemistry, morphology, and cell cycle analysis, the identified Artemia RSK was established to be specifically activated during the post-embryonic and early larval developmental stages when arrested cells of encysted embryos resumed mitoses. In vivo knockdown of RSK activity by RNA interference, kinase inhibition, and antibody neutralization consistently induced defective larvae with distinct gaps between the exoskeleton and internal tissues. In these abnormal individuals, mitoses were detected to be largely inhibited in the affected regions. These results display the requirement of RSK activity during Artemia development and suggest its role in termination of cell cycle (G(2)/M phase) arrest and promotion of mitogenesis. Our findings may, thus, provide insights into the regulation of cell division during Artemia post-embryonic development and reveal further aspects of RSK functions.

Methane-derived authigenic carbonates from the Ulleung basin sediments, East Sea of Korea

Authigenic carbonates were sampled in methane-enriched piston core sediments collected from gas venting sites on the western continental slope of the Ulleung Basin, East Sea of Korea. Multidisciplinary investigations on these carbonates, including the scanning electronic microscope (SEM) observations and mineralogical-geochemical compositions, were carried out to identify the carbon and oxygen sources and the forming mechanism of these carbonates. The authigenic carbonates from the study area correspond to semi-consolidated, compact concretions or nodules ranging from 2 to 9 cm in size. X-ray diffraction and electron microprobe analyses showed that most of the sampled carbonate concretions were composed of almost purely authigenic high-Mg calcite (10.7-14.3 mol% MgCO3). Characteristically, microbial structures such as filaments and rods, which were probably associated with the authigenic minerals, were abundantly observed within the carbonate matrix. The carbonates were strongly depleted in delta C-13 (-33.85 parts per thousand to -39.53 parts per thousand Peedee Belemnite (PDB)) and were enriched in delta O-18 (5.16-5.60 parts per thousand PDB), indicating that the primary source of carbon is mainly derived from the anaerobic oxidation of methane. Such methane probably originated from the destabilization of the underlying gas hydrates as strongly supporting from the enriched O-18 levels. Furthermore, the strongly depleted delta C-13 values (-60.7 parts per thousand to -61.6 parts per thousand PDB) of the sediment void gases demonstrate that the majority of the gas venting at the Ulleung Basin is microbial methane by CO2 reduction. This study provides another example for the formation mechanism of methane-derived authigenic carbonates associated with gas-hydrate decomposition in gas-seeping pockmark environments. (c) 2009 Elsevier Ltd. All rights reserved.

潮间带纤毛虫原生动物和小型底栖动物生态学研究

微型和小型底栖动物是底栖微/小食物网的重要构成。相对浮游生态系统, 迄今国际间对底栖食物网的认知极为欠缺。这一方面是由于微型生物形态和功能上的复杂性和多样性, 另一方面原因在于研究方法的障碍—主要是微型和小型底栖动物的定量提取和定性分析。本研究首先进行了方法学改良, 并应用新方法对底栖微食物网的重要功能类群—纤毛虫原生动物和小型底栖动物进行了不同生境的周年按月采样, 定性及定量研究的同时, 联系环境因子对微型和小型底栖生物的环境监测进行了探讨。 微型和小型底栖生物的定量研究首先涉及到目标生物在沉积物中的有效提取, 目前硅胶液提取是普遍使用的方法, 其中Ludox液主要应用于小型生物, 它不但价格便宜而且比重合适, 因此在常规生态研究中被广为接受。不过, Ludox易与于海水中的阳离子产生凝结而无法直接用于微型生物; 目前唯一直接应用于微型生物提取的是Percoll硅胶液, 但其昂贵的价格使其在常规生态研究中受到极大限制。本研究以价格低廉的Ludox 硅胶液结合定量蛋白银染色 (QPS) 技术开发了一种新的方法, 即Ludox-QPS法。主要流程为: 样品采集与固定、淘洗/稀释降盐、Ludox密度梯度离心、过滤浓缩和琼脂包埋, QPS染色、永久封片及鉴定计数。添加已知数量的纤毛虫至无生物底泥的重获实验表明, 该密度梯度离心的提取率大于94%; 该方法对自然沉积物中纤毛虫的提取率达97.6%, 对沙质、泥沙质和泥质中海洋线虫的提取率分别达97%、96.9% 和97.8%。对比实验表明, 经QPS制片获得的小型动物的丰度和类群数量与传统方法相当或更高, 尤其当小个体虫体占优势时, 该法显示出较传统方法 (导致数量低估) 更为明显的定量优越性。该方法除用于纤毛虫和小型动物的定量分析外, 还具有较高的分类分辨率, 染色后的纤毛虫原生动物大多类群可鉴定到属, 部分可鉴定到种, 以此可在群落水平上研究其生态作用。 根据新开发的Ludox-QPS技术, 在大沽河潮间带依据盐度梯度选定2个站位 (IIQ和营海) 进行了周年按月采样, 对底栖纤毛虫和小型底栖动物进行了定量研究。纤毛虫原生动物在IIQ和营海的年平均丰度分别为2236 inds./10 cm2 和935 inds./10 cm2 (28 inds./ml 和12 inds./ml), 平均生物量分别为119.1 gC/10 cm2和54.2 gC/10 cm2 (1.5 gC /ml 0.7 gC/ml)。丰度的季节变化趋势为: 春天 > 秋天 > 夏天 > 冬天。垂直分布上, 在营海分布于表层0-0.5 cm 的比例为57.1%, 分布于0.5-2 cm、2-4 cm和4-8 cm比例分别为23.1%、11.4% 和8.5%; 13个月中除12月份外, 4-8 cm均有一定数量的纤毛虫分布; 而在IIQ, 97% 的纤毛虫分布在0-0.5 cm, 分布在0.5-2 cm、2-4 cm和4-8 cm比例分别为2.4%、0.4%和0.2%, 4-8 cm的分布只发生在春季和秋季。纤毛虫的多样性季节变化明显, 春秋季物种丰富, 两个站点每毫升沉积物的平均物种数分别为18和6。Two-Way Crossed ANOSIM 分析表明纤毛虫群落在月份间和站点间的差异极其显著。Pseudochilodonopsis sp., Chilodontopsis sp., Euplotes sp.及Prorodon sp.是表征两个生镜中纤毛虫群落的主要类群。 同时, 发现了14个小型生物类群, 其中线虫在IIQ和营海的丰度优势度分别为97.4% 和78.6%。小型动物在IIQ和营海的年平均丰度分别为4793 inds./10 cm2和8915 inds./10 cm2 (60 inds./ml和111 inds./ml), 其生物量分别为1068.8 gC /10 cm2和1790 gC /10 cm2 (13.4 gC/ml和22.4 gC/ml)。小型底栖动物的丰度在IIQ的季节变化为: 夏季 (7888 inds./10cm2) > 秋季 (5447 inds./10cm2) > 春季 (3731 inds./10cm2) > 冬季 (2780 inds./10cm2); 在营海则完全相反: 冬季 (15579 inds./10cm2) > 春季 (10691 inds./10cm2) > 秋季 (6611 inds./10cm2) > 夏季 (4667 inds./10cm2)。小型底栖动物和纤毛虫的相对重要性存在明显的区域和季节差异。 纤毛虫原生动物、小型动物及环境因子的相关分析表明, 纤毛虫的丰度和多样性与温度和盐度及有机质含量显著相关, 与小型动物没有显著相关性; 群落结构分析表明, 温度、有机质和小型动物的丰度的组合与纤毛虫群落丰度的相关系数为0.345; 盐度、脱镁叶绿素、有机质和小型动物生物量的组合与纤毛虫群落多样性的相关系数为0.403。依据海洋线虫和桡足类的比值 (N/C) 推测, IIQ 可能存在严重的有机污染, 营海则存在明显的季节波动, 8月和9月及2月可能是污染最严重的季节, 这种状况在纤毛虫群落结构的CLUSTER聚类中得到验证。虽然目前尚没有形成有关微型底栖生物-纤毛虫原生动物的污染检测的直接依据, 但本研究说明纤毛虫群落的确对环境污染具有一定的感应度, 而且这种感应和利用小型生物的主要类群估算的污染检测 (N/C) 存在一定程度的关联。 90年代早期有关青岛湾有机污染带的研究表明, 经彻底截污后, 其环境状况向良性发展。进一步了解该湾的健康状况, 2006.5-2007.5月对该湾沙质和泥沙质的小型动物进行周年按月采样。小型动物在泥沙质和砂质沉积物中的年平均丰度分别为4853 ± 1292 inds./10 cm2和1528 ± 569 inds./10 cm2; 年平均总生物量分别为1434.1 ± 897.0 gC /10cm2和720.7 ± 353.8 gC/10cm2。沙质底小型生物的丰度季节波动明显, 6月份和12月份最高, 3月份和9月份最低; 泥沙质季节波动不明显, 6月份最高。两个站点均有48%的小型动物分布在0-0.5 cm 表层, 海洋线虫在表层的分布比例分别为48% (泥沙质) 和34% (砂质)。共检获14个小型动物类群, 其中线虫在泥沙质和砂质沉积物中的年平均丰度分别4619 ± 1255 inds./10cm2和1014 ± 376 inds./10cm2, 其丰度优势度分别为95.2%和66.4%。其它在丰度上占优势的类群, 泥沙质依次为多毛类 (1.5%)、甲壳幼体 (1.5%) 和桡足类 (0.7%); 沙质依次为: 甲壳类幼体 (12.6%)、腹毛类 (8.3%) 和 桡足类 (6.2%)。CLUSTER聚类分析表明, 泥沙质和和砂质中小型生物的丰度组成具有64%的相似性。BIOENV分析表明, 温度、盐度、中值粒径和粘土粉砂含量的组合最能解释不同月份之间和不同站位间的差异, 其相关系数为0.614。依据小型生物的丰度和类群组成, 表明泥沙质底尚存一定的有机污染。

迟缓爱德华氏菌基因组fosmid文库的构建、opp基因簇的克隆及aroA基因缺失突变株的构建

本研究构建了迟缓爱德华氏菌(Edwardsiella tarda)LSE40 基因组fosmid文库，该文库共包含2 500个克隆，插入片段平均大小为33.6kb，文库总容量约84Mb，覆盖E.tarda LSE40基因组（按5Mb计算）超过16倍。随机挑取1 000个fosmid克隆进行双末端测序共得到1 741条高质量的序列，序列平均长度546 bp，全长949 997bp，约为E.tarda基因组的19％。将这些序列提交到KEGG自动注释服务器KAAS对所得序列进行代谢途径分析，得到E.tarda LSE40的KO (KEGG Orthology) 注释。分析结果表明，与代谢途径相关的基因有932条序列，与环境信息处理相关基因283条，与遗传信息处理相关基因220条，与细胞进程和人类疾病相关的基因分别为64条和16条。同时将序列进行BlastX，按照微生物致病性共同主题找到61个毒力相关基因。Fosmid文库的建立和部分基因组序列的生物信息学分析为进一步研究E.tarda LSE40的致病机制、代谢机制和生理生态机制提供了丰富的物质基础。 通过比较基因组的方法，从E.tarda LSE40 fosmid文库克隆到编码寡肽透过酶的opp基因簇，该基因簇全长6 741bp，含有5个ORF，依次编码OppA-B-C-D-F 5个蛋白；位于oppA和oppB的间隔区和oppF之后的非编码区各有一个茎环结构，推测分别为oppA和opp基因簇的转录终止子。以细菌OppA的保守结构域SBP_bac_5构建系统发生树，结果显示E.tarda LSE40与同属细菌E.ictaluri的亲缘关系最近，与肠杆菌科细菌的亲缘关系较近，与革兰氏阳性细菌的亲缘关系较远，表明OppA的SBP_bac_5结构域可作为细菌分类鉴定的依据。 从E.tarda LSE40 fosmid文库克隆aroA基因全序列，该序列全长1 287bp，编码428个氨基酸，与鲶鱼爱德华氏菌(E. ictaluri)氨基酸相似性在94%，与其他肠杆菌科菌如Escherichia coli和Yersinia enterocolitica相似性在73%-74%。通过In-frame deletion构建了E.tarda LSE40 aroA缺失突变株。与野生型相比，aroA突变株的半数致死量LD50提高了62倍。在牙鲆接种~106cfu/ml的E.tarda细菌时，接种野生型细菌的牙鲆在6天内全部死亡，濒死鱼的细菌数达7.97×108cfu/ 100mg；而接种aroA突变株的牙鲆没有出现死亡，28天后检测不到细菌的存在。实验结果为进一步评价aroA突变株作为减毒活疫苗打下了基础。

复杂地质条件下高精度地震勘探技术研究与应用-以泌阳凹陷为例

In order to carry out high-precision three-dimensional "integration" for the characteristics of the secondary seismic exploration for Biyang Depression, in the implementation process, through a combination of scientific research and production, summed up high-precision seismic acquisition, processing and interpretation technologies suitable for the eastern part of the old liberated areas, achieved the following results: 1. high-precision complex three-dimensional seismic exploration technology series suitable for shallow depression Biyang block group. To highlight the shallow seismic signal, apply goal-based observing system design, trail from the small panel to receive and protect the shallow treatment of a range of technologies; to explain the use of three-dimensional visualization and coherent combination of full-body three-dimensional fine interpretation identification of the 50-100 m below the unconformity surface and its formation of about 10 meters of the distribution of small faults and improve the small block and stratigraphic unconformity traps recognition. 2. high-precision series of three-dimensional seismic exploration technology suitable for deep depression Biyang low signal to noise ratio of information. Binding model using forward and lighting technology, wide-angle observation system covering the design, multiple suppression and raise the energy of deep seismic reflection processing and interpretation of detailed, comprehensive reservoir description, such as research and technology, identified a number of different types of traps. 3. high-precision seismic exploration technology series for the southern Biyang Depression high steep three-dimensional structure. The use of new technology of seismic wave scattering theory and high-precision velocity model based on pre-stack time migration and depth migration imaging of seismic data and other high-precision processing technology, in order to identify the southern steep slope of the local structure prediction and analysis of sandstone bedrock surface patterns provide a wealth of information.

孔南地区孔一段、孔二段储层构型及改善开发效果对策研究

Integrating geology, core, well-logging, experimental data, and production data, with the guide of sequence stratigraphy, sedimentology, reservoir exploitation geology and other disciplines’ theories, combinating the sequence stratigraphy and Maill’s reservoir architectures concepts and theories, the research and analysis methods of non-marine fan-delta reservoir architectures are systemly set out. And the correspondence of reservoir structures, sedimentology and reservoir geology is established. An integral and systematical research approach and theory and conception of reservoir architecture is developed, which enriched the reservoir research theory. Considering the requirement to the reservoir research in different development phase, the six classification systems of reservoir architectures are brought up. According to different reservoir’s connection and location of Ek different levels of reservoir architecture, 3 types, 20 kind architectures styles are summarized. The research about undisturbed reservoir characterization is launched, through analyzing reservoir characterization to pour water to the different reservoirs of Kongnan region, the changing regular pattern of reservoir quality during pouring water process is summarized. Combined with the actual zone data, inner-well reservoir geometry relationship of injection-production model is designed, and the models of development process are dynamic simulated. In view of seven laboratory samples of 3 types, six order architecture unit of braided stream, fan-delta and nearshore subsea apron in Kongnan region, the remaining oil distribution model is determined. Using the geo-statistics methods dissect the key regions, the tectono-stratigraphical model and the reservoir parameters model are established. The distribution of the characteristics of the underground reservoir is quantitatively described. Based on the reservoir research, carrying out the development of different characteristics of reservoir, the development pattern and countermeasures are determined. The relationships between reservoir structure levels and reservoir development stages are summed up, the relationships between architecture unit of different levels and exploration develop stages are determined.

Asistencia Técnica en los procesos productivos identificados como críticos en el aseguramiento de la calidad en los procesos productivos. Municipio de Chimichagua, corregimiento de Candelaria - Cesar. Artecan - Asociación de Artesanos de Candelaria.

11 hojas : ilustraciones, fotografías a color.

The day-breaking, if not the sun-rising of the Gospell with the Indians in New-England.

University of California Libraries

itmBench: Generalized API for Internet Traffic Managers

Internet Traffic Managers (ITMs) are special machines placed at strategic places in the Internet. itmBench is an interface that allows users (e.g. network managers, service providers, or experimental researchers) to register different traffic control functionalities to run on one ITM or an overlay of ITMs. Thus itmBench offers a tool that is extensible and powerful yet easy to maintain. ITM traffic control applications could be developed either using a kernel API so they run in kernel space, or using a user-space API so they run in user space. We demonstrate the flexibility of itmBench by showing the implementation of both a kernel module that provides a differentiated network service, and a user-space module that provides an overlay routing service. Our itmBench Linux-based prototype is free software and can be obtained from http://www.cs.bu.edu/groups/itm/.

Communicable Memory and Lazy Barriers for Bulk Synchronous Parallelism in BSPk

Communication and synchronization stand as the dual bottlenecks in the performance of parallel systems, and especially those that attempt to alleviate the programming burden by incurring overhead in these two domains. We formulate the notions of communicable memory and lazy barriers to help achieve efficient communication and synchronization. These concepts are developed in the context of BSPk, a toolkit library for programming networks of workstations|and other distributed memory architectures in general|based on the Bulk Synchronous Parallel (BSP) model. BSPk emphasizes efficiency in communication by minimizing local memory-to-memory copying, and in barrier synchronization by not forcing a process to wait unless it needs remote data. Both the message passing (MP) and distributed shared memory (DSM) programming styles are supported in BSPk. MP helps processes efficiently exchange short-lived unnamed data values, when the identity of either the sender or receiver is known to the other party. By contrast, DSM supports communication between processes that may be mutually anonymous, so long as they can agree on variable names in which to store shared temporary or long-lived data.