镍系顺丁橡胶的长链支化对链缠结及其他性能的影响

采用动态力学和应力-应变法,研究了镍系顺丁橡胶(Ni-BR)的长链支化对动态模量、缠结链段数目及其分子量等因素的影响。认为Ni-BR的支化度大者,动态模量、屈服强度、T_(300)/σ_y值高,缠结链段分子量小,缠结链段数止多,本体粘度大,缠结网络紧密,分子运动和解缠结困难,橡胶的结晶能力降化,甚至不能结晶。

Analysis of the expression and antioxidative property of a peroxiredoxin 6 from Scophthalmus maximus

Peroxiredoxins (Prxs) are a group of antioxidant proteins that protect cells from oxidative damage caused by various peroxides. To date, six different isoforms of peroxiredoxin (Prx1 to Prx6) have been identified, of which, Prx6 belongs to the 1-Cys Prx subfamily. Although Prx6 of several fish species have been reported at sequence level, there are very few documented studies on the potential function of fish Prx6. In this report, we describe the identification and analysis of a Prx6 homologue, SmPrx6, from turbot Scophthalmus maximus. The full length cDNA of SmPrx6 contains a 5'- untranslated region (UTR) of 60 bp, an open reading frame of 666 bp, and a 3'-UTR of 244 bp. The deduced amino acid sequence of SmPrx6 shares 81-87% overall identities with known fish Prx6. In silico analysis identified in SmPrx6 a conserved Prx6 catalytic motif, PVCTTE, and the catalytic triads putatively involved in peroxidase and phospholipase A2 activities. Expression of SmPrx6 was detected in most fish organs, with the highest expression levels found in blood and heart and the lowest level in spleen. Experimental challenges with bacterial pathogens and poly(I:C) upregulated SmPrx6 expression in liver and spleen in a manner that is dependent on the challenging agent and the tissue type. Treatment of cultured primary hepatocytes with H2O2 enhanced SmPrx6 expression in a dose-dependent manner. Recombinant SmPrx6 expressed in and purified from Escherichia coli exhibited thiol-dependent antioxidant activity and could protect cultured hepatocytes from H2O2-induced oxidative damage. Taken together, these results indicate that SmPrx6 is a Prx6 homologue with antioxidative property and is likely to be involved in both cellular maintenance and protective response during host immune defense against bacterial infection. (C) 2010 Elsevier Ltd. All rights reserved.

Contrasting chemical and isotopic compositions of organic matter in Changjiang (Yangtze river) estuarine and East China Sea shelf sediments

To examine the source and preservation of organic matter in the shelf sediments of the East China Sea (ECS), we measured bulk C/N and isotopes, organic biomarkers (n-alkanes and fatty acids) and compound-specific (fatty acids) stable carbon isotope ratios in three sediment cores collected from two sites near the Changjiang Estuary and one in the ECS shelf. Contrasting chemical and isotopic compositions of organic matter were observed between the estuarine and shelf sediments. The concentrations of total n-alkanes and fatty acids in the shelf surface sediments (0-2 cm) were 5-10 times higher than those in estuarine surface sediments but they all decreased rapidly to comparable levels below the surface layer. The compositions of n-alkanes in the estuarine sediments were dominated by C-26-C-33 long-chain n-alkanes with a strong odd-to-even carbon number predominance. In contrast, the composition of n-alkanes in the shelf sediment was dominated by nC(15) to nC(22) compounds. Long-chain (> C-20) fatty acids (terrestrial biomarkers) accounted for a significantly higher fraction in the estuarine sediments compared to that in the shelf sediment, while short-chain (< C-20) saturated and unsaturated fatty acids were more abundant in the shelf surface sediments than in the estuarine sediments. Stable carbon isotopic ratios of individual fatty acids showed a general positive shift from estuarine to shelf sediments, consistent with the variations in bulk delta(CTOCTOC)-C-13. These contrasts between the estuarine and shelf sediments indicate that terrestrial organic matter was mainly deposited within the Changjiang Estuary and inner shelf of ECS. Post-depositional diagenetic processes in the surface sediments rapidly altered the chemical compositions and control the preservation of organic matter in the region.

Community structure and seasonal dynamics of planktonic ciliates along salinity gradients

The ciliate community structure and seasonal dynamics in a solar saltern of the Yellow Sea were studied based oil 4 sampling dates and 8 stations with salinities from 27.7 parts per thousand to 311.0 parts per thousand. The effects of the type and concentration of the fixative used (Lugol's and Bouin's) were tested at the first sampling date. Fixative type and fixative concentration had significant effects on ciliate abundance and blovolume, with 1% Lugol's giving the best results. A detailed investigation using live observations and protargol staining techniques revealed a total of 98 morphospecies from 8 sampling stations. There was obvious seasonal variation in species composition at most of the stations, but this tended to be less distinct with increasing salinity, as the dominant ciliate group shifted from oligotrichs to heterotrichs. Ciliate abundance varied from 4.40 x 10(1) to 2.11 x 10(5) cells l(-1) and biomass ranged between 2.39 and 9.87 x 10(3) mu g Cl-1 (at a salinity of 147.6 parts per thousand). Both abundance and biomass decreased abruptly when salinity exceeded 100-150 parts per thousand. Statistical analyses Suggested that the dynamics of ciliate abundance and biomass were regulated by both salinity and by season, but those of diversity and species richness were mainly controlled by salinity and both significantly decreased with increasing salinity. (C) 2009 Elsevier GmbH. All rights reserved.

Trichodinid ectoparasites (Ciliophora, Peritrichia) from the tiger puffer Takifugu rubripes in the Yellow Sea, with revision of Trichodina jadranica Raabe,1958

Two ectoparasitic ciliates, Trichodina fugu Imai et al., 1997 and T. jadranica Raabe, 1958, found on the gills and skin of the maricultured tiger puffer Takifugu rubripes on the China coast of the Yellow Sea, were studied using the dry silver nitrate method. Trichodina fugu is distinguished by its almost rod-shaped denticle blades. Trichodina jadranica is usually described as a small trichodinid with a clear central circle in the adhesive disc and with a low number of denticles. However, the data available suggest that the species is highly variable in morphometry and the Chinese population represents the largest in body size and denticle dimensions found to date. Based on the revision of T. jadranica, two major morphotypes, each represented by several populations are classified, differing in the shape of the blades, viz., distinctly curved and sickle-shaped with pointed distal ends (as in the classical T. jadranica) vs. less curved and more or less rectangle-like with rounded distal ends (as in T. domerguei gobii). Trichodina domerguei gobii Raabe,.1959, which was synonymised with T. jadranica, is thus elevated to species rank. Furthermore, Trichodina jadranica noblei Lom, 1970 has straight and stout blades with broadly rounded distal ends and is raised to species rank: T noblei Lom, 1970. Trichodina jadranica sensu Xu et al., 1995 shows high similarities in denticle shape and dimensions as well as the central granule pattern with T chlamydis Xu et al., 1999. Thus, it is synonymised with the latter species.

Chromosomal mapping of the major ribosomal RNA genes in the dwarf surfclam (Mulinia lateralis Say)

Chromosomal location of the major ribosomal RNA genes (rRNA) were studied in the dwarf surfclam (Mulinia lateralis, Say) using fluorescence in situ hybridization (FISH). FISH probes for the rRNA genes were made by polymerase chain reaction (PCR), labeled with digoxigenin-11-dUTP and detected with fluorescein-labeled antidigoxigenin antibodies. Mulinia lateralis had a diploid number of 38 chromosomes and all chromosomes were telocentric. FISH with the rRNA probe produced positive and consistent signals on two pairs of chromosomes: Chromosome 15 with a relative length of 4.6% and Chromosome 19, the shortest chromosome. Both loci were telomeric. The rRNA location provides the first physical landmark of the M. lateralis genome.

一种用于食草动物粪便显微组织分析的临时装片新技术

粪便显微组织分析法是研究食草动物食性的主要方法,其常规装片技术需要使用Hoyer's装片介质对植物碎片进行封片,而Hoyer's封片液的粘性易导致植物碎片在装片过程中发生卷曲和重叠,影响植物碎片的识别效果.本文提出的新装片技术采用没有粘性的饱和NaCl溶液代替Hoyer's装片介质,结合特定的定量取样方法和装片程序,可以有效地减少植物碎片的卷曲率和重叠率.对比试验显示,新装片技术可使植物碎片卷曲率从10.4%下降至3.8%,重叠率从25%下降至8.1%,说明新装片技术在减少植物碎片卷曲和重叠方面明显优于常规装片方法.

海北高寒草甸生态系统定位站辐射气候特征

以2000—03到2001—02的辐射观测资料，分析了海北高寒草甸生态系统定位站地区辐射及各分光辐射的变化特征．将为高寒草甸生态系统的物质循环、能量流动、草地生产力形成机制等问题的研究提供科学依据。结果表明：海北站区Eg、Er、UV、PAR、NIR和En具有明显的日、年变化，年内其总量分别达6278．867MJ／m^2、1515．139MJ／m^2、311．242MJ／m^2、2576．777MJ／m^2、3397．404MJ／m^2和2542．950MJ／m^2，其中在植物生长期的5—9月分别为3181．215MJ／m^2、698．021MJ／m^2、165．955MJ／m^2、1133．965MJ／m^2、1673．871MJ／m^2和1668．805MJ／m^2。年内Er、UV、PAR、NIR和Eh占Eg的比例分别为0．242、0．048、0．410、0．540和0．410，在植物生长期分别为0．219、0．052、0．413、0.528和0．527。对Eg和PAR提出了下列形式的模拟求算式．Eg=Eg0（0．089．7＋0．9768S／S0）和PAR=-3.8044＋0.4177％，模拟效果较好，可利用有关常规气象观测资料进行估算。

海北高寒草甸的季节冻土及在植被生产力形成过程中的作用

海北高寒矮嵩草草甸区植被下的草毡寒冻雏形土属季节性冻土, 因温度低, 冻土在年内的每个月均可发生. 一般在11月中旬可形成稳定的季节冻结层, 至翌年3～4月冻土层厚度最大可达230 cm. 从3月下旬到4月中旬开始, 土壤开始消融, 至6月下旬到7月上旬冻土全部消失. 分析发现, 季节冻土在高寒草甸植被生产力形成过程中有着积极的影响作用, 主要表现在: 1)季节冻土的存在和维持将给高寒植物生长提供良好的土壤水分, 对植物初期营养生长发育有利, 可弥补春夏之交时降水不足所引起的干旱胁迫影响; 2)季节冻土的长时间维持, 有利于植物残体和土壤有机质留存于土壤, 并随土壤冻结和融化过程发生迁移, 可提高土壤肥力; 3)较高的土壤水分有利于土壤胡敏酸的形成, 可保证植物生长所需的其它有机元素的供给; 4)冻土层所形成较高的土壤水分使土体热容量加大, 从而调节因气候异常波动引起的土壤温度变化; 5)季节冻土的变化对植物地上年生产量形成有一定的影响作用, 表现出从10月或11月开始, 土壤冻结速率快, 对提高植物地上年生产量有利. 这也证实, 在未来气候变暖的趋势下, 土壤有机质将加快分解速度, 土壤水分因受温度升高 , 冻结期缩短, 其贮存能力降低; 受温度升高的影响, 地表蒸发能力加大, 若降水仍保持目前的水平, 土壤水分将明显减少, 将导致高寒草甸植被生产力有下降的可能.

细叶亚菊挥发油中抑制垂穗披碱草的化合物的分离与鉴定

用气相色谱－质谱联机光谱分析法，分离、提纯，鉴定细叶亚菊挥发油中抑制垂穗披碱草生长的化合物49种，有α－蒎烯、莰烯、蒈品－３－烯、桉叶油精、胡薄荷酮、樟脑、萜品烯－４－醇和乙酸菊烯酸酯８种主要化合物，而占总细对亚菊挥发油的82.80％。其中樟脑最多，胡薄荷酮和桉对油精为次。

Nitrous oxide emissions from two alpine meadows in the Qinghai-Tibetan Plateau

Nitrous oxide (N2O) emission was measured in a Kobresia humilis meadow and a Potentilla fruticosa meadow in the Qinghai-Tibet Plateau from June 2003 to July 2006. Five treatments were setup in the two alpine meadows. Two bare soil treatments were setup in the K. humilis meadow (BSK) and in the P. fruticosa meadow (BSP) by removing the above- and belowground plant biomass. Three plant community treatments were setup with one in the K. humilis meadow (herbaceous community in the K. humilis meadow-HCK) and two in the P. fruticosa meadow (herbaceous community in the P. fruticosa meadow-HCP, and shrub community in the P. fruticosa meadow-SCP). Nitrous oxide emission from BSP was estimated to be 38.1 +/- 3.6 mu g m(-2) h(-1), significantly higher than from BSK (30.2 +/- 2.8 mu g m(-2) h(-1)) during the whole experiment period. Rates from the two herbaceous blocks (HCK and HCP) were close to 39.5 mu g m(-2) stop h(-1) during the whole experimental period whereas shrub community (SCP) showed significant high emission rates of N2O. Annual rate of N2O emission was estimated to be 356.7 +/- 8.3 and 295.0 +/- 11.6 mg m(-2) year(-1) from the alpine P. fruticosa meadow and from the alpine K. humilis meadow, respectively. These results suggest that alpine meadows in the Qinghai-Tibetan Plateau are an important source of N2O, contributing an average of 0.3 Tg N2O year(-1). We concluded that N2O emission will decrease, due to a predicted vegetation shift from shrubs to grasses imposed by overgrazing.

Phylogenetic origins of the Himalayan endemic Dolomiaea, Diplazoptilon and Xanthopappus (Asteraceae : Cardueae) based on three DNA regions

Background and Aims It is an enduring question as to the mechanisms leading to the high diversity and the processes producing endemics with unusual morphologies in the Himalayan alpine region. In the present study, the phylogenetic relationships and origins of three such endemic genera were analysed, Dolomiaea, Diplazoptilon and Xanthopappus, all in the tribe Cardueae of Asteraceae.Methods The nuclear rDNA internal transcribed spacer (ITS) and plastid trnL-F and psbA-trnH regions of these three genera were sequenced. The same regions for other related genera in Cardueae were also sequenced or downloaded from GenBank. Phylogenetic trees were constructed from individual and combined data sets of the three types of sequences using maximum parsimony, maximum likelihood and Bayesian analyses.Key Results The phylogenetic tree obtained allowed earlier hypotheses concerning the relationships of these three endemic genera based on gross morphology to be rejected. Frolovia and Saussurea costus were deeply nested within Dolomiaea, and the strong statistical support for the Dolomiaea-Frolovia clade suggested that circumscription of Dolomiaea should be more broadly redefined. Diplazoptilon was resolved as sister to Himalaiella, and these two together are sister to Lipschitziella. The clade comprising these three genera is sister to Jurinea, and together these four genera are sister to the Dolomiaea-Frolovia clade. Xanthopappus, previously hypothesized to be closely related to Carduus, was found to be nested within a well-supported but not fully resolved Onopordum group with Alfredia, Ancathia, Lamyropappus, Olgaea, Synurus and Syreitschikovia, rather than the Cardinis group. The crude dating based on ITS sequence divergence revealed that the divergence time of Dolomiaea-Frolovia from its sister group probably occurred 13.6-12.2 million years ago (Ma), and the divergence times of the other two genera, Xanthopappus and Diplazoptilon, from their close relatives around 5.7-4.7 Ma and 2.0-1.6 Ma, respectively.Conclusions The findings provide an improved understanding of the intergeneric relationships in Cardueae. The crude calibration of lineages indicates that the uplifts of the Qiinghai -Tibetan Plateau since the Miocene might have served as a continuous stimulus for the production of these morphologically aberrant endemic elements of the Himalayan flora.

Theoretical study on the mechanism for the addition reaction of SiH3 with propylene and acetic acid

To explore the reactivities of alkene (-CH=CH2) and carboxy (-COOH) group with H-Si under UV irradiation, the addition mechanism for the reactions of SiH3 radical with propylene and acetic acid was studied by using the B3LYP/6-311++ G(d,p) method. Based on the surface energy profiles, the dominant reaction pathways can be established; i.e., SiH3 adds to the terminal carbon atom of the alkene (-CH=CH2) to form an anti-Markovnikov addition product, or adds to the oxygen atom of the carboxy group (-COOH) to form silyl acetate (CH3-COOSiH3). Because the barrier in the reaction of the carboxy group (39.9 kJ/ mol) is much larger than that of alkene (11.97 kJ/mol), we conclude that the reaction of bifunctional molecules (e.g., omega-alkenoic acid) with H-Si under irradiation condition is highly selective; i.e., the alkene group (-CH= CH2) reacts with SiH3 substantially faster than the carboxyl group (-COOH), which agrees well with the experimental results. This provides the possibility of preparing carboxy-terminated monolayers on silicon surface from omega-alkenoic acids via direct photochemical reaction.

真空机器人传输模组软件控制平台的构建

论文来源于新松公司的科技部超大规模集成电路制造装备重大专项：300mm智能真空机械手关键技术及样机研制。在查阅了大量资料的基础上，进一步研究了集束型设备传输模组控制软件的功能分区、作动机制及实现方法，最终完成了真空机械手上位机控制程序和集束型设备图形仿真程序的设计。 在本论文中，笔者首先提出了集束型设备控制软件以及仿真软件的架构方案，其次，规划了真空机械手的指令集合、串口通信协议与命令应答格式，编写了基于串口通信的控制界面程序，并给出了传输模组控制软件系统层的整合方案。在此基础上，建立真空机械手的运动学模型，利用CAD建模工具及OpenGL图形库编写了能够完全再现集束型设备运转情形的图形仿真程序，并使图形能够与机械手本体实时联动。此外，研究了不同晶圆流程模式下的集束型设备时间调度算法，为实现可编程化控制奠定了基础。