含环氧端基酚酞聚芳醚酮E-PEK的合成及表征

由酚酞和4,4′-二氯二苯酮经亲核缩聚制得了一系列不同分子量的含—OK端基的聚醚酮低聚物,将其与环氧氯丙烷反应得到了分子量为1000～8000的含环氧端基聚芳醚酮(E-PEK)。用IR和~1H NMR表征了E-PEK的分子链结构,测定了T_g、溶解性和熔融粘度。研究了E-PEK/DDE体系的固化,固化后树脂的T_(g∞)=183～215℃,与低聚物的初始分子量有关。

LIQUID-CHROMATOGRAPHY AMPEROMETRIC DETECTION OF CATECHOL, RESORCINOL, AND HYDROQUINONE WITH A COPPER-BASED CHEMICALLY MODIFIED ELECTRODE

A copper-based chemically modified electrode (CME) has been constructed and characterized for flow-through amperometric detection of catechol, resorcinol, and hydroquinone. Novel potential dependence of the detector response was first obtained for these analytes at the Cu CME, where negative peaks together with positive ones were observed in one definite chromatogram using amperometric detection. Its advantages in chromatographic applications were demonstrated. From these observations it is proposed that the detector response was governed by formation of copper complexes with the solutes. A dynamic linear range over two orders of magnitude was obtained, when operating the detector at +0.10 V vs. SCE, from which ng detection limits were achieved.

石墨炉原子吸收光谱法测定磷时基体改进剂的应用研究

本文阐述几种基体改进剂测定磷的效果,发现Pd/Ca混合基体改进剂对测定植物和动物组织中磷最理想,利用氘灯扣背景,其特征量为8.2ng,吸光度线性范围为0～0.220,磷含量为0.144％和1.35％时,相对标准偏差为2％左右,精密度好,抗干扰能力强,测定茶树叶和贻贝中磷比较理想。

THERMAL-ANALYSIS OF POLYARYLENE ETHER SULFONES AND POLYIMIDES

Some results on the thermal analysis of polyimides and polyaryl ether sulfones, some reactions and the purity determination of the monomers, and the thermal stability and kinetic analysis of the thermo-oxidative degradation of these polymers are described.

异戊二烯均相聚合催化剂

分别用C_6H_5CH_2Cl,CH_2-CHSiCl_3,CH_ SiHCl_2,(CH_3)_2SiCl_2,(CH_3)_3CCl,CH_2—CHCH_2Cl,Cl_3SiCH_2CH_2SiCl_3代替非均相催化剂Nd(naph)_3-Al_2Et_3Cl-Al(i-Bu)_2H(简称Nd-Cl-Al)中的助催化剂后,除C_6H_5CH_2Cl,CH_2=CHSiCl_3,CH_SiHCl_2形成悬浊催化剂外,在Cl/Nd<8(mol比)时,其他氯化物均形成均相催化剂,并能催化异戊二烯均相聚合,得到顺式-1,4含量约95％,[η]约3 dL/g的聚合物。分别用(CH_3)_3CCl和(CH_3)_2SiCl_2代替Cl所组成的两催化剂,其催化活性接近,最佳Al/Nd和Cl/Nd值分别为40和2.5;异戊二烯浓度为10％—20％时,转化率不随其浓度的改变而变化。符合一级反应动力学特征。

SYNTHESIS AND X-RAY CRYSTAL-STRUCTURE OF A MONOPENTAMETHYLCYCLOPENTADIENYL DERIVATIVE OF GADOLINIUM (NA(MU-2-THF)[(C5ME5)GD(THF)]2(MU-2-CL)3(MU-3-CL)2)2.6THF

The reaction of GdCl3 with 1 equiv of NaC5Me5 generates a neutral complex C5Me5GdCl2(THF)3 and a novel complex {Na(mu-2-THF)[(C5Me5)Gd(THF)]2(mu-2-Cl)3(mu-3-Cl)2}2.6THF whixh recrystallizes from THF in triclinic, the space group P1BAR with unit cell dimentions of a 12.183(4), b 13.638(6), c 17.883(7) angstrom, alpha-110.38(3), beta-94.04(3), gamma-99.44(3)-degrees, V 2721.20 angstrom-3 and D(calc) 1.43 g cm-3 for Z = 1. Least-squares refinement of 2170 observed reflections led to a final R value of 0.047. The title complex consists of two Na(mu-2-THF)[(C5Me5)Gd(THF)]2(mu-3-Cl)3(mu-3-Cl)2 units bridged together via two mu-2-THF to Na coordination. Each Gd ion is surrounded by one C5Me5 ligand, two mu-3-Cl, two mu-2-Cl and one THF in a distorted octahedral arrangement with average Gd-C(ring) 2.686(33), Gd-mu-2-Cl 2.724(7), Gd-mu-3-Cl 2.832(8) and Gd-O 2.407(11) angstrom. The sodium ion coordinates to two bridging THF, two mu-2-Cl and two mu-3-Cl to form a distorted octahedron with average Na-mu-2-O, Na-mu-2-Cl and Na-mu-3-Cl of 2.411(21), 2.807(15) and 2.845(12) angstrom, respectively.

稀土化合物的铝热法还原研究

目前,稀土铝合金的制备方法有混熔法(又称对掺法)、以铝为液态阴极的熔盐电解法和铝热还原法等三种。从能源和经济效益考虑,铝热还原法工艺简单,操作方便,在适当条件下可获得较高的稀土收率,是一种较有发展前途的稀土铝合金制备方法。鲁化一等曾采用铝热还原法成功地制取了RE-ZL104合金,并已投入了工业生产。通常在铝合金中应用较多的是混合稀土,对单一稀土化合物的铝热还原法制备稀土铝合金的报道很少。

结晶聚合物的中间层

介绍了结晶聚合物中间层概念及各种实验技术所提供的中间层存在的证据。附25篇参考文献。

Ce:BaAlF_5晶体生长及其光谱特性

采用坩埚下降法生长了 Ce:BaAlF_5单晶、X 射线衍射表明其结构为α-BaAlF_5构型,属于正交晶系,晶胞参数为α=5.146(?),b=7.191(?),c=19.647(?)。测定了晶体的反射光谱、吸收光漕、激发光谱和荧光光谱。Ce~(3+)离子在290nm 附近有一个强吸收峰,为4f-5d 能级的跃迁。在292nm 激发下,有306.5nm 和324nm 两个发射峰、即Ce~(3+)的~2D 能级到~2F_5/2和~2F_7/2能级的跃迁发射。晶体在紫外光照射下发紫光和兰白光。在254nm 激发下,除了 Ce_~(3+)的发射峰,还存在351nm和494nm 两个发光峰,前者与 Ce~(3+)的324nm 发射峰部分重叠,后者为对称性较好的宽带峰。这两个发光峰被认为是晶体缺陷产生的色心发光。

Cloning and characterization of a novel C-type lectin gene from shrimp Litopenaeus vannamei

In invertebrates, C-type lectins play crucial roles in innate immunity responses by mediating the recognition of host cells to pathogens and clearing microinvaders, which interact with carbohydrates and function as pattern recognition receptors (PRRs). A novel C-type lectin gene (LvLec) cDNA was cloned from hemocytes of Litopenaeus vannamei by expressed sequence tag (EST) and rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA of LvLec was of 618 bp, consisting of a 5'-terminal untranslated region (UTR) of 60 bp and a 3'-UTR of 87 bp with a poly (A) tail. The deduced amino acid sequence of LvLec possessed all conserved features critical for the fundamental structure, such as the four cysteine residues (Cys(53), Cys(128), Cys(144), Cys(152)) involved in the formation of disulfides bridges and the potential Ca2+/carbohydrate-binding sites. The high similarity and the close phylogenetic relationship of LvLec shared with C-type lectins from vertebrates and invertebrates. The structural features of LvLec indicated that it was an invertebrate counterpart of the C-type lectin family. The cDNA fragment encoding the mature peptide of LvLec was recombined and expressed in Escherichia coli BL21(DE3)-pLysS. The recombinant protein (rLvLec) could agglutinate bacteria E. coli JM109 depending on Ca2+, and the agglutination could be inhibited by mannose and EDTA. These results indicated that LvLec was a new member of C-type lectin family and involved in the immune defence response to Gram negative bacteria in Litopenaeus vannamei. (C) 2008 Elsevier Ltd. All rights reserved.

Identification and characterization of a virulence-associated protease from a pathogenic Pseudomonas fluorescens strain

Pseudomonas fluorescens is an aquaculture pathogen that can infect a number of fish species. The virulence mechanisms of aquatic P. fluorescens remain largely unknown. Many P. fluorescens strains are able to secrete an extracellular protease called AprX, yet no AprX-like proteins have been identified in pathogenic P. fluorescens associated with aquaculture. In this study, a gene encoding an AprX homologue was cloned from TSS, a pathogenic A fluorescens strain isolated from diseased fish. In TSS, AprX is secreted into the extracellular milieu, and the production of AprX is controlled by growth phase and calcium. Mutation of aprX has multiple effects, which include impaired abilities in interaction with cultured host cells, adherence to host mucus, modulation of host immune response, and dissemination and survival in host tissues and blood. Purified recombinant AprX exhibits apparent proteolytic activity, which is optimal at pH 8.0 and 50 degrees C. The protease activity of recombinant AprX is enhanced by Ca2+ and Zn2+ and reduced by Co2+. Cytotoxicity analyses showed that purified recombinant AprX has profound toxic effect on cultured fish cells. These results demonstrate that AprX is an extracellular metalloprotease that is involved in bacterial virulence. (C) 2009 Elsevier B.V. All rights reserved.

A Holocene paleotemperature record based on radiolaria from the northern Okinawa Trough (East China Sea)

Using a radiolarian-based transfer function, mean annual sea surface temperature (SST) and seasonal temperature range are reconstructed through the last 10,500yrs in the northern Okinawa Trough. Down-core SST estimates reveal that throughout the Holocene the changes of mean annual SST display a three-step trend: (i) an early Holocene continuous warming between 10,500 and 8500yr BP which ends up with a abrupt cooling at about 8200yr BP; (ii) a relatively stable middle Holocene with high SST that lasted until 3200yr BP; and (iii) a late-Holocene distinct SST decline between 3200 and 500yr BP. This pattern is in agreement with the ice core and terrestrial paleoclimatic records in the Chinese continent and other regions of the world. Five cooling events with abrupt mean annual SST drops, which occur at similar to 300-600, 1400, 3100, 4600-5100 and 8200yr BP, are recognized during the last 10,500yrs. Comparison of our results with records of GISP2 ice core and marine sediment in North Atlantic region suggests these cooling events are strongly coupled, which implies a possible significant climatic correlation between high- and low-latitude areas. (C) 2007 Elsevier Ltd and INQUA. All rights reserved.

Food utilization of adult flatfishes co-occurring in the Bohai Sea of China

Stomach contents were examined of 4527 adult individuals of 12 flatfish species collected during the 1982 - 1983 Bohai Sea Fisheries Resources Investigation. Their food habits, diet diversity, similarity of prey taxa, trophic niche breadth and diet overlap were systematically analysed. Ninety-seven prey species belonging to the Coelenterata, Nemertinea, Polychaeta, Mollusca, Crustacea, Echinodermata, Hemichordata and fish were found and five of them were considered to be principal prey for flatfishes: Alpheus japonicus, Oratosquilla oratoria, Alpheus distinguendus, Loligo japonicus and Crangon affinis. Among the flatfishes, Paralichthys olivaceus was piscivorous, whereas Pseodopleuronectes yokohamae and Pseudopleuronectes herzensteini both had polychaetes and molluscs as their main prey groups. Pleuronichthys cornutus was classified as a polychaete-mollusc eater, with a strong preference for crustaceans. Verasper variegatus, Cynoglossus semilaevis, Eopsetta grigorjewi and Cleisthenes herzensteini ate crustaceans. Kareius bicoloratus was classified as a mollusc-crustacean eater: Cynoglossus abbreviatus, Cynoglossus joyneri and Zebrias zebra were grouped as crustacean-fish eaters. However, Z. zebra also took polychaetes and C. abbreviatus and C. joyneri preyed on some molluscs. Trophic relationships among the flatfishes were complicated, but they occupied distinctive microhabitats in different seasons and selected their specific prey items, which was favourable to the stability of the flatfish community in the Bohai Sea.