Effect of swelling response of the support particles on ethylene polymerization

Macroporous and modified macroporous poly(styrene-co-methyl methacrylate-co-divinylbenzene) particles (m-PS and mm-PS) supported Cp2ZrCl2 were prepared and applied to ethylene polymerization using methylaluminoxane (MAO) as cocatalyst. The influences of the swelling response of the support particles on the catalyst loading capabilities of the supports as well as on the activities of the supported catalysts were studied. It was shown that the Zr loadings of the supports and the activities of the supported catalysts increased with the swelling extent of the support particles. The m-PS or mm-PS supported catalysts exhibited very high activities when the support particles were well swollen, whereas those catalysts devoid of swelling treatment gave much lower activities. Investigation on the distribution of the supports in the polyethylene by TEM indicated that the swelling of the support particles allowed the fragmentation of the catalyst particles. In contrast, the fragmentation of the support particles with poor swelling was hindered during ethylene polymerization.

Electropolyrnerization of polypyrrole on PFIL-PSS-modified electrodes without added support electrolytes

A novel polyelectrolyte-functionalized ionic liquid (PFIL)/poly(4-styrene sulfonate sodium) (PSS) modified electrode composed of the coaxial and coplanar working, reference and counter electrodes, was used to electropolymerize the polypyrrole. The PFIL/PSS was modified on the integrated electrode (IE) and connected by the working, reference and counter electrodes, resulting in an available charge transfer and lower Ohmic potential drop between the working and counter electrodes. Then polypyrrole (PPy) film was successfully prepared electrochemically without any participation of supporting electrolytes, only in a pyrrole monomer solution. The resulting PPy film in PFIL/PSS matrix exhibited a preferable electroactivity. Subsequently, influence of the modifications on the formation of PPy was further discussed. The results indicated that the synergetic cooperation of PFIL and PSS components accomplished such a successful electropolymerization of PPy.

Proteomic analysis of differentially expressed proteins in lymphoid organ of Fenneropenaeus chinensis response to Vibrio anguillarum stimulation

To gain an insight into the function of shrimp lymphoid organ at protein level, we analyzed the proteome of lymphoid organ in healthy Chinese shrimp Fenneropenaeus chinensis (F. chinensis) through two-dimensional gel electrophoresis (2-DE) based proteomic approach. A total of 95 spots representing 75 protein entries were identified by liquid chromatography tandem mass spectrometry (LC-MS/MS) with both online and in-house database. According to Gene Ontology (GO) annotation of biological process, the identified proteins were classified into 13 categories. Among them, approximately 36% of proteins related to cytoskeleton are noticeable. Then, a comparative proteomic approach was employed to investigate the differentially expressed proteins in lymphoid organ of Vibrio anguillarum-challenged F. chinensis. At 24 h post-injection (hpi), 17 differentially expressed protein spots were successfully identified, including 4 up-regulated protein spots (represent 4 proteins: cathepsin L protein similar to squid CG16901-PC, protein kinase C and protein similar to T-complex Chaperonin 5 CG8439-PA), and 13 down-regulated protein spots (represent 9 proteins: actin, beta-actin, cytoplasmic actin CyII, alpha tubulin, beta tubulin, protein similar to proteasome delta, vacuolar ATP synthase subunit B, elongation factor 2, carboxypeptidase B). These data may help us to understand the function of lymphoid organ and the molecular immune mechanism of shrimp responsive to pathogen infection. (C) 2010 Elsevier Ltd. All rights reserved.

中国明对虾免疫系统中抗氧化相关基因的克隆与表达分析

对虾病害在世界范围内的广泛传播，给水产养殖和沿海农村经济造成了重大损失。深入开展对虾免疫机制研究并在此基础上寻找对虾疾病防治的有效方法已成为当务之急。研究表明，当对虾等甲壳动物受到外界病原刺激时，其体内的吞噬细胞在吞噬活动中会激活磷酸己糖支路的代谢，引起呼吸爆发，产生多种活性氧分子。另外，受到病原侵染的对虾还会产生其他多种免疫反应，这些免疫反应将消耗大量的能量（ATP），产能的呼吸链会加速运转，由此也会引发大量活性氧的产生。这些活性氧分子可以杀灭入侵的病原微生物，但同时由于活性氧分子反应的非特异性，它们也会对宿主的细胞、组织和器官造成严重伤害，进而导致对虾生理机能的损伤和免疫系统的破坏。所以，消除对虾体内因过度免疫反应产生的过量氧自由基将能够增强其抵御病原侵染的能力，提高免疫力。本论文从中国明对虾体内克隆了线粒体型超氧化物歧化酶（mMnSOD）、胞质型超氧化物歧化酶（cMnSOD）、过氧化氢酶（Catalase）和过氧化物还原酶（Peroxiredoxin）等四种与免疫系统相关的抗氧化酶基因，分析了它们的分子结构特征，组织分布及应答不同病原刺激的表达变化模式，并对其中的mMnSOD基因和Peroxiredoxin基因进行了体外重组表达、分离纯化和酶活性分析。 采用RACE技术从中国明对虾血细胞中克隆了两个超氧化物歧化酶（SOD）基因，通过序列比对分析发现，其中一个为mMnSOD基因，另一个为cMnSOD基因。mMnSOD基因的cDNA全长为1185个碱基，其中开放阅读框为660个碱基，编码220个氨基酸，其中推测的信号肽为20个氨基酸。多序列比对结果显示中国明对虾mMnSOD基因的推导氨基酸序列与罗氏沼虾、蓝蟹的推导氨基酸序列同源性分别为88%和82%。Northern blot结果表明，该基因在对虾的肝胰脏、血细胞、淋巴器官、肠、卵巢、肌肉和鳃等组织中均有表达。半定量RT-PCR结果显示，对虾感染病毒3 h时，该基因在血细胞和肝胰脏中的转录水平显著升高。此外，通过构建原核表达载体，本研究对该基因进行了体外重组表达，并对纯化的重组蛋白进行了质谱鉴定和酶活分析。cMnSOD基因的cDNA全长为1284个碱基，其中开放阅读框为861个碱基，编码287个氨基酸。多序列比对结果显示中国明对虾cMnSOD基因的推导氨基酸序列与斑节对虾和凡纳滨对虾的同源性高达98%和94%。组织半定量结果显示，cMnSOD基因在对虾被检测的各个组织中均有表达。 另外，半定量RT-PCR结果表明，对虾感染病毒23h时，该基因在肝胰脏中的转录上升到正常水平的3.5倍；而感染后59 h时，该基因在血细胞中的转录上升到正常水平的2.5倍。 利用根据其他生物过氧化氢酶保守氨基酸序列设计的简并引物，结合RACE技术，从中国明对虾肝胰脏中克隆到了过氧化氢酶基因的部分片段，片段长1725个碱基。多序列比对结果发现目前所得中国明对虾Catalase基因部分片段的推导氨基酸序列与罗氏沼虾和皱纹盘鲍Catalase氨基酸序列的同源性分别达到95%和73%。通过实时荧光定量PCR技术对中国明对虾Catalase基因在各个组织中的分布情况及病毒感染后该基因在血细胞和肝胰脏中的转录变化进行了研究。结果发现，该基因在肝胰脏、鳃、肠和血细胞中表达水平较高，在卵巢、淋巴器官和肌肉中的表达水平相对较弱；感染病毒23 h和37 h时，对虾血细胞和肝胰脏中该基因mRNA的表达量分别出现显著性上升。 依据中国明对虾头胸部cDNA文库提供的部分片段信息，结合SMART-RACE技术，从中国明对虾肝胰脏中克隆到了过氧化物还原酶基因（Peroxiredoxin）， 该基因的cDNA全长为942个碱基，其中开放阅读框为594个碱基，编码198个氨基酸。中国明对虾Peroxiredoxin基因的推断氨基酸序列与伊蚊、文昌鱼和果蝇等Peroxiredoxin基因的推断氨基酸序列同源性分别为77%、76%和73%。其蛋白理论分子量为22041.17 Da，pI为5.17。Northern blot结果表明，Peroxiredoxin基因在对虾的肝胰脏、血细胞、淋巴器官、肠、卵巢、肌肉和鳃等组织中均有表达。实时荧光定量PCR结果显示，弧菌感染后，该基因在对虾血细胞和肝胰脏中的转录水平都有明显变化并且表达模式不同。另外，对该基因进行了体外重组表达，并对纯化的重组蛋白进行了质谱鉴定和酶活性分析。酶活性分析表明，复性后的重组蛋白能在DTT存在的条件下还原H2O2。

An application of the analytic hierarchy process and fuzzy logic inference in a decision support system for forage selection

Forage selection plays a prominent role in the process of returning cultivated lands back into grasslands. The conventional method of selecting forage species can only provide attempts for problem-solving without considering the relationships among the decision factors globally. Therefore, this study is dedicated to developing a decision support system to help farmers correctly select suitable forage species for the target sites. After collecting data through a field study, we developed this decision support system. It consists of three steps: (1) the analytic hierarchy process (AHP), (2) weights determination, and (3) decision making. In the first step, six factors influencing forage growth were selected by reviewing the related references and by interviewing experts. Then a fuzzy matrix was devised to determine the weight of each factor in the second step. Finally, a gradual alternative decision support system was created to help farmers choose suitable forage species for their lands in the third step. The results showed that the AHP and fuzzy logic are useful for forage selection decision making, and the proposed system can provide accurate results in a certain area (Gansu Province) of China.

Graphitic nanofilaments as novel support of Ru-Ba catalysts for ammonia synthesis

A novel graphitic-nanofilament-(GNF-) supported Ru-Ba catalyst is prepared and used in ammonia synthesis reaction. The Ru-Ba/GNFs catalyst shows remarkably high activity and stability for ammonia synthesis, which can be attributed to high purity and graphitization of GNFs with unique structure. TEM micrographs of the Ru-Ba/GNFs catalysts show that Ru metal particles uniformly disperse on the outer wall of GNFs, and the particles become bigger than that before ammonia synthesis reaction after 50 h of operation at 500degreesC and 7.0 MPa, probably due to the Ru crystals covered by promoter and support materials and/or sintering of Ru crystals. (C) 2002 Elsevier Science (USA).

Effect of support and acidity of catalyst on the direct oxidation of ethylene to acetic acid

The selective oxidation of ethylene to acetic acid was investigated on Pd-acid/support catalyst system. The catalytic activity is influenced strongly by the acidity of the catalyst. The stronger the catalyst acidity the higher the catalytic activity. The nature of the support also influences the activity of the catalyst substantially. The catalyst has highest activity when it exhibits highest acidity on silica.