ELECTROCHEMICAL SCANNING-TUNNELING-MICROSCOPY

An ECSTM apparatus with an ideal tip using a homemade SSX-1A STM instrument has been constructed. STM and ECSTM tips were made by electrochemical etching and insulating with paraffin, silicon rubber or epoxy resin under an optical microscope. In situ imag

ON THE ANALYSIS OF THE END-NOTCHED FLEXURE SPECIMEN FOR MEASURING MODE-II FRACTURE-TOUGHNESS OF COMPOSITE-MATERIALS

This paper deals with the correction of mode II strain energy release rate, G(II), of composite laminates measured with the end-notched flexure (ENF) specimen. A derivation is given of the expressions for compliance and strain energy release rate, in whic

THE RADIATION STABILITY OF PERFLUOROALKOXY RESIN

By examining the changes in melting temperature, heat of fusion, tensile strength and ultimate elongation at 150-degrees-C, and weight loss, radiation effects on perfluoroalkoxy resins (PFA) were investigated. The results show that at the temperatures used here the predominant effect caused by radiation on PFA is degradation of the molecular weight. The radiation stability is much better than that of polytetrafluoroethylene, however.

AN ALL-SOLID-STATE LITHIUM POLYANILINE RECHARGEABLE CELL

The performance of an all-solid-state cell having a lithium negative electrode, a modified polyethylene oxide (PEO)-epoxy resin (ER) electrolyte, and a polyaniline (PAn) positive electrode has been studied using cyclic voltammetry, charge/discharge cycling, and polarization curves at various temperatures. The redox reaction of the PAn electrode at the PAn/modifed PEO-ER interface exhibits good reversibility. At 50-80-degrees-C, the Li/PEO-ER-LiClO4/PAn cell shows more than 40 charge/discharge cycles, 90% charge/discharge efficiency, and 54 W h kg-1 discharge energy density (on PAn weight basis) at 50-mu-A between 2 and 4 V. The polarization performance of the battery improves steadily with increase in temperature.

A STUDY OF MODE-I DELAMINATION RESISTANCE OF A THERMOPLASTIC COMPOSITE

This paper describes the mode I delamination behaviour of a unidirectional carbon-fibre/poly(phenylene ether ketone)(PEK-C) composite. Tests have been performed on double cantilever beam (DCB) specimens. Several data reduction schemes are used to obtain the critical strain energy release rate, G(IC), and the results are compared. It is shown that when using a DCB test to determine the fracture toughness, corrections must be employed. The experimental methods have been described for ascertaining the correction terms, and the results are consistent after modification. Some of the authors' results are different from those of other authors, particularly the negative correction term for crack length, the larger exponent (n > 3) in the relationship C = Ra(n), and decrements of flexural modulus with the crack growth when using the simple beam theory to predict the bending behaviour of DCB specimens. The possible reasons are discussed.

Chaetopyranin, a benzaldehyde derivative, and other related metabolites from Chaetomium globosum, an endophytic fungus derived from the marine red alga Polysiphonia urceolata

Cultivation of the endophytic fungus Chaetomium globosum, which was isolated from the inner tissue of the marine red alga Polysiphonia urceolata, resulted in the isolation of chaetopyranin (1), a new benzaldehyde secondary metabolite. Ten known compounds were also isolated, including two benzaldehyde congeners, 2-(2 ',3-epoxy-1 ',3 '-heptadienyl)-6-hydroxy- 5-(3-methyl-2-butenyl) benzaldehyde (2) and isotetrahydroauroglaucin (3), two anthraquinone derivatives, erythroglaucin (4) and parietin (5), five asperentin derivatives including asperentin ( 6, also known as cladosporin), 5 '-hydroxy-asperentin-8-methylether (7), asperentin-8-methyl ether (8), 4 '-hydroxyasperentin (9), and 5 '-hydroxyasperentin (10), and the prenylated diketopiperazine congener neoechinulin A (11). The structures of these compounds were determined on the basis of their spectroscopic data analysis (H-1, C-13, H-1-H-1 COSY, HMQC, and HMBC NMR, as well as low- and high-resolution mass experiments). To our knowledge, compound 1 represents the first example of a 2H-benzopyran derivative of marine algal-derived fungi as well as of the fungal genus Chaetomium. Each isolate was tested for its DPPH (1,1-diphenyl-2-picrylhydrazyl) radical-scavenging property. Compounds 1-4 were found to have moderate activity. Chaetopyranin (1) also exhibited moderate to weak cytotoxic activity toward several tumor cell lines.

Expression, purification of recombinant flounder MRF4 protein in Escherichia coli and analysis of its polyclonal antibodies

MRF4 is one of muscle regulatory factors and plays critical roles during skeletal muscle development. The muscle development is important for the fish growth which is an important economic factor for the fish culture. To analyze the function of MRF4 in fish, the founder MRF4 antibody was prepared. The flounder MRF4 was cloned, ligated into prokaryotic expression vector pET-30b and expressed in strain E. coli BL21 (130). The recombinant flounder MRF4 fusion protein was soluble and purified with cobalt IMAC resins. To prepare MRF4 polyclonal antibodies, rabbits were immunized with the soluble protein and the increasing level of antibodies was determined by Western blot. Also, the endogenous flounder MRF4 was recognized by the anti-serum. The result further proved the existence of the anti-MRF4 antibody in the anti-serum, which will be useful for studies on the function of flounder MRF4.

三种红藻活性物质的发现及松节藻醇提物抗糖尿病药理研究

海藻是海洋生物中的一大类群，由于其特殊的生活环境，能够代谢产生大量结构独特多变和活性特殊多样的代谢产物，是化学和生物活性多样性研究的重要对象之一。我国海域辽阔，海藻资源丰富，为寻找结构新颖、生理活性独特的先导化合物，加强对海藻资源的开发利用，本论文对中国沿海的三种海洋红藻进行了化学成分和生物活性研究，同时对山东青岛海域生物量丰富的一种海洋红藻松节藻进行了动物体内抗糖尿病活性研究。 利用正相硅胶柱色谱、Sephadex LH-20柱色谱以及反相HPLC和重结晶等现代分离手段，对山东青岛沿海的红藻扇形叉枝藻（Gymnogongrus flabelliformis）进行了系统的化学成分研究，从中得到单体化合物26个，通过波谱学方法（IR、MS、NMR等）鉴定了他们的结构，分别为(3R,6R,7E)-(+)-3-O-phenylacetyl- 4,7-megastigmadiene-9-one（1），(3R,7E)-(-)-3-O-phenylacetyl-5,7-megastigmadiene -9-one（2），(3S,6R,7E)-(+)-3-hydroxyl-4,7-megastigmadien-9-one（3），(3S,5R,6S,7E)- (-)-3-hydroxy-5,6-epoxy-7-megastigmene-9-one（4），(3S,5S,6R,7E)-(+)-3-hydroxy- 5,6-epoxy-7-megastigmene-9-one（5），Dehydrovomifoliol（6），(3R)-(-)-4-[(2R,4S)-4- acetoxy-2-hydroxy-2,6,6-trimethylcyclohexylidene]-3-buten-2-one（7），2,3,3′-三溴-4,4′,5,5′-四羟基-1′-乙氧甲基双苯基甲烷（8），2,2′,3,3′-四溴-4,4′,5,5′-四羟基双苯基甲烷（9），3-溴-4,5-二羟基苯甲醛（10），2,3-二溴-4,5-二羟基苯甲基甲醚（11），2,3-二溴-4,5-二羟基苯甲醇（12），N, N-二甲基酪胺（13），4-羟基苯甲酸乙酯（14），4-羟基苯甲基乙醚（15），4-羟基苯乙基乙酯（16），4-羟基苯乙酸甲酯（17），4-羟基苯甲醛（18），豆甾-4-烯-3-酮（19），胆甾-4-烯-3-酮（20），胆甾醇（21），尿嘧啶（22），尿嘧啶核苷（23），腺嘌呤核苷（24），丁二酸（25），5-羟基-4-甲基-5-戊基-2,5-二氢呋喃-2-酮（26）。其中化合物1、2为新化合物，化合物3为新天然产物，所有化合物均为首次从该属海藻中分离得到。通过 MTT 法对部分单体化合物进行了肿瘤细胞毒活性筛选, 结果表明，化合物8、9、10、12对筛选的所有细胞株均有较强细胞毒活性，化合物11对人肺癌细胞株（A549）、人肝癌细胞株（Bel 7402）、人结肠癌细胞株（HCT-8）有一定细胞毒活性。通过研究单体化合物对小鼠腹腔巨噬细胞TNF-分泌的影响，对其进行抗炎活性筛选，结果表明，化合物8、9、11、13、17、23、24、25对小鼠腹腔巨噬细胞TNF-分泌表现出明显的抑制作用。 从采自山东荣成镆铘岛的红藻小珊瑚藻（Corallina pilulifera）的乙酸乙酯萃取物中分离得到16个单体化合物，通过波谱学方法鉴定化合物结构14个（另外2个正在鉴定中），分别为2α-乙氧酰基-2β-羟基-A-降胆甾-5-烯-4-酮（27），胆甾-4-烯-3-酮（28），胆甾醇（29），3β-羟基-胆甾-5,24(28)-二烯-7-酮（30），2α-羟基-胆甾-4-烯-3-酮（31），6α-羟基-胆甾-4-烯-3-酮（32），3β-羟基-胆甾-5-烯-7-酮（33），(E)-phytol epoxide（34），Phytenal（35），3,7,11,15- tetramethyl-hexadec-2-en-1-oll（Phytol）（36），Loloilide（37），(3S,5R,6S,7E)-(-)-3-hydroxy-5,6-epoxy-7- megastigmene-9-one（38），Dehydrovomifoliol（39），4-羟基苯甲醛（40）。其中，化合物 31为新天然产物，化合物27为首次从植物中分离得到，所有化合物均为首次从该种海藻中分离得到。通过 MTT 法对分离得到的单体化合物进行了肿瘤细胞毒活性筛选,化合物27和化合物32对筛选的所有肿瘤细胞株均有细胞毒活性，且化合物27对人胃癌细胞株（BGC-823）、人结肠癌细胞株（HCT-8）和人卵巢癌细胞株（A2780）具有中等强度抑制活性。化合物28、化合物31和化合物33对人肝癌细胞株（Bel 7402）、人结肠癌细胞株（HCT-8）和人卵巢癌细胞株（A2780）有一定细胞毒活性。 从采自广西北海涠洲岛的多管藻Polysiphonia sp.的乙酸乙酯萃取物中分离得到6个单体化合物，通过波谱学方法鉴定化合物结构5个（另外1个仍在鉴定），分别为胆甾醇（41），3,7,11,15-tetramethyl-hexadec-2-en-1-ol（Phytol）（42），3-吲哚甲醛（43），4-羟基苯甲醛（44），4-羟基苯甲酸（45）。 对山东青岛沿海的松节藻 (Rhodomela confervoides) 乙醇提取物进行了初步的体内抗糖尿病活性研究，采用链脲佐菌素诱导的2型糖尿病（STZ-DM）大鼠模型对其进行体内降糖实验，结果发现，松节藻乙醇提取物在糖尿病大鼠体内不仅具有显著的降血糖作用，且呈现良好的量–效关系，而且能够纠正糖尿病引发的物质代谢紊乱，增加体重，提高试验动物的成活率，因此具有良好的应用开发前景。

两种海藻提取物的化学成分和生物活性的研究及其应用

本论文的研究工作由两部分组成，第一部分研究了海带（Laminaria japonica）水提取物中的活性物质，并研究了提取物对蔬菜促生长的影响及其作用机制。第二部分对三列凹顶藻(Laurencia tristicha)乙醇提取物的乙酸乙酯相进行了活性筛选和化学成分研究，并对其中分离得到的单体化合物进行了生物活性筛选。 第一部分主要以中国人工养殖的海带为原料，使用与海藻多糖生产相结合的提取技术并浓缩其中的有效成分。对浓缩提取物进行了蔬菜的农田效果实验，并对作物抗旱性能的增加、作物硝酸盐积累的减少、作物品质的改善、以及作物抵抗病毒病的能力等影响进行了作用机制方面的研究。海藻浓缩提取物进行的农田效果实验表明：作物抗旱型相对含水量RWC值在92%~94%之间；病毒病的防治效果最高可达到91%；作物的品质有明显的改善，最重要的是首次发现海藻提取物有降低蔬菜中硝酸盐的含量（硝酸盐的含量是与有机蔬菜区别的重要指标之一）的作用。该部分研究工作的创新性主要体现在：（1）首次在国内外提出和采用与海藻多糖生产相结合的提取技术。该技术的应用不但减少了提取成本，使工业化生产成为可能,更重要的是使我国的海藻工业生产可能实现高值化和开辟综合利用的新途径。（2）首次发现海藻中的小分子海藻多糖具有和细胞激动素、甜菜碱、植物生长素等活性物质同样的生物活性。 第二部分的研究是在查阅了大量的近20年来国内外有关红藻凹顶藻中化学成分研究的相关文献的基础上，对凹顶藻中的次生代谢产物进行了综述。该论文主要是通过对红藻三列凹顶藻的95%乙醇提取物的乙酸乙酯相进行化学成分分析和生物活性筛选以期能够发现具有药用前景的活性先导化合物。 为了寻找具有生物活性的化合物，我们对采自我国南海硇洲岛海域的红藻三列凹顶藻的95%乙醇提取物的乙酸乙酯相进行了活性筛选。采用MTT法对其在KB细胞株、Bel-7402细胞株、PC-3M细胞株、MCF-7细胞株、Ketr-3细胞株模型上进行了细胞毒活性测试；采用酶模型对其进行了Na+,K+-ATPase的抑制活性测试；采用MTT法对其在犬主动脉血管模型上进行了血管平滑肌细胞增殖抑制活性测试；结果表明，三列凹顶藻的95%乙醇提取物的乙酸乙酯相对Na+,K+-ATPase和犬血管平滑肌细胞增殖具有一定的抑制活性。 利用正相和反相色谱、Sephadex LH-20色谱以及反相HPLC等手段进行分离纯化，从我国南海海域的红藻三列凹顶藻中分离得到33种化学成分，通过波谱学方法（IR、MS、NMR）以及X-ray单晶衍射试验对其化学结构进行了确证，其中化合物L1~L8为新结构化合物，化合物L5为具有新骨架的全新结构化合物，化合物L9~L13为新天然产物，化合物L18和L22系首次从海洋生物中获得，所有化合物均为首次从该属海藻中得到。新化合物L1~L8均为倍半萜类化合物，命名分别为：(1R,3R)-(-)-3-(3-hydroxy-4-methylphenyl)- 1,3-dimethyl–2-methylidene cyclopentanol (L1), (1R,3R)-(-)-3-(4-methylphenyl)-1,3-dimethyl-2-methylidenecyclopentanol (L2)， (1R, 3R)-(-)-3-(2-hydroxy-4-methylphenyl)-1,3-dimethyl–2–methylidenecyclopentanol (L3)，(+)-(1S,2R)–2-(3–hydroxy–4–methylphenyl)-1,2-[3.1.0]bicy-clohexane (L4)，()-(1S,2R) -5-hydroxy–6–methyl-spiro-dihydrobenzofuran-2(3H),2-{1-methyl-[3.1.0]bicyclohexane} (L5), (+)-6-methyl-2-(p-tolyl)hept-4-en-2,6-diol (L6)，(3R,3aS,8bS)-(-)-2,3,3a,8b–tetrahydro–7-bromo – 3 a– hydroxymethyl - 3, 6, 8b - trimethyl-1H- cyclopenta[b] benzofuran (L7 )，(3R, 3aS, 8bS) - (-) - 2,3,3a,8b–tetrahydro–3 a–hydroxymethyl-3,6,8b -trimethyl -1H – cyclopenta [b] benzofuran (L8)。25个已知结构化合物确定为：(+)-(1R,2R)-4-bromo-1,5, 9–trimethyl–12– methylidene–8–oxa-tricyclo[7.2.1.02]dodeca-2,4,6-triene (L9)，(3S,3aR,8bS)-(-)-2,3,3a, 8b– tetra -hydro–7-bromo–3–hydroxy-3,3a,6,8b-tetramethyl-1H-cyclopenta[b]benzofu- ran (L10 )，(3R, 3aR, 8bS) - (-) - 2, 3, 3a, 8b – tetrahydro – 7 - bromo – 3 – hydroxy - 3,3a,6,8b - tetramethyl - 1H - cyclopenta [b] benzofuran (L11 )，(3S,3aR,8bS) - (-) - 2, 3, 3a, 8b – tetrahydro –3–hydroxy -3, 3a, 6, 8b - tetramethyl-1H-cyclopenta[b]benzofuran (L12 )， ( 3aR, 8bS) - (-) - 3a,8b –dihydro–7 - bromo – 3, 3a, 6, 8b - tetramethyl - 1H - cyclopenta[b]benzofuran (L13 )，aplysinol (L14 ) ，aplysin (L15)，laurebiphenyl (L16)，johnstonol (L17)，gossonorol (L18)，7,10-epoxy-ar- bisabol-11-ol (L19)，10-epi-7,10-epoxyarbisabol-11-ol (L20) 3β-hydroxy- 5α, 6α-epoxy- β- ionone (L21 )，3β-hydroxy-5β,6β-epoxy-β-ionone (L22 )，胆甾醇 (L23 )，胆甾-5-烯-3β,7α二醇胆甾-5-烯-3β,7α二醇 (L24)，β-谷甾醇 (L25)，叶绿醇 (L26 )，玉米黄素 (L27 )，对羟基苯甲醛 (L28 )，3-吲哚甲醛 (L29 )，1-O-十六烷酰基-3-O-β-D-吡喃半乳糖基-丙三醇(L30 )，1-O-十八烷酰基-3-O-β-D-吡喃半乳糖基-丙三醇 (L31 )，丙三醇-1-软脂酸单酯 (L32 )，正十六碳酸 (L33 )。 采用MTT法对其中23个单体化合物在Bel-7402细胞株、BGC-823细胞株、A549细胞株、A2780细胞株、HCT-8细胞株和HELL细胞株模型上进行了细胞毒活性测试；采用MTT法对其中13个单体化合物在犬主动脉血管模型上进行了血管平滑肌细胞增殖抑制活性测试；结果表明，部分单体化合物显示出一定的生物活性。

牙鲆rag基因的克隆及表达研究

牙鲆在中国北方沿海地区形成了大规模的工厂化养殖，成为我国海水养殖的一大重要产业。然而疾病的频繁发生严重阻碍了这一产业的发展，为了保证牙鲆产业稳定、健康、持续地发展，开展鱼类免疫系统的基础研究，提高鱼类抵抗病原菌侵害的能力，本研究从牙鲆免疫系统的个体发育过程入手，克隆了其rag（recombination activating gene）基因，在此基础上对其组织特异性表达进行了分析。 研究结果表明牙鲆rag1基因由4个外显子和3个内含子组成，第一个外显子位于5’非翻译区，这一外显子存在两种不同的剪切方式。牙鲆rag1基因编码1068个氨基酸。牙鲆rag2基因的编码区序列长为1602 bp，编码533个氨基酸，没有在牙鲆rag2基因编码区内发现内含子的存在。rag基因间序列长为3128 bp，两个基因共用一段3’非编码区。 本试验通过RT-PCR检测发现，牙鲆的rag1和rag2基因在头肾和体肾中均有表达。整装原位杂交结果表明，牙鲆在受精后第8天开始起有rag1和rag2基因的表达，主要在胸鳍前面，腮背部的部位表达，这个区域与后来胸腺出现的位置相一致。冰冻切片结果显示，rag是在靠近咽部的区域有表达。石蜡切片原位杂交结果显示，rag基因在胸腺中的表达显示出不均一性，着色较深的为皮层区，而着色比较浅的为髓部。 将牙鲆rag1基因的一部分（编码559个氨基酸）和rag2全基因序列（编码533个氨基酸）插入到表达质粒pProEXTM HTa上，在大肠杆菌E. coli BL-21中进行体外表达与分析，结合BD TALONTM Metal Affinity Resins亲和柱纯化了RAG2蛋白。

Sesquiterpenes from the red alga Laurencia tristicha

Seven new sesquiterpenes (1-7), together with seven known sesquiterpenes, aplysin (8), aplysinol (9), gossonorol (10), 7,10-epoxy-ar-bisabol-11-ol (11), 10-epi-7,10-epoxy-ar-bisabol-11-ol (12), johnstonol (13), and laurebiphenyl (14), have been isolated from the red alga Laurencia tristicha. The structures of new compounds were established as laur-11-en-2,10-diol (1), laur-11-en-10-ol (2), laur-11-en-1,10-diol (3), 4-bromo-1,10-epoxylaur-11-ene (4), cyclolauren-2-ol (5), laurentristich-4-ol (6), and ar-bisabol-9-en-7,11-diol (7) by means of spectroscopic methods including IR, HRMS, and ID and 21) NMR techniques. Compound 6 possessed a novel rearranged skeleton. All compounds were tested against several human cancer cell lines including lung adenocarcinoma (A549), stomach cancer (BGC-823), hepatoma (Bel 7402), colon cancer (HCT-8), and HELA cell lines. Laurebiphenyl (14) showed moderate cytotoxicity against all tested cell lines, with IC50 values of 1.68, 1.22, 1.91, 1.77, and 1.61 mu g/mL, respectively. Other compounds were inactive (IC50 > 10 mu g/mL).

A New Triterpenoid from Amoora dasyclada

Five compounds were isolated from the EtOH extraction of the stem of Amoora dasyclada (How et T. Chen) C. Y. Wu (Meliaceae). On the basis of spectroscopic methods, their structures were elucidated as 24, 25-epoxy-tirucall-7-ene-3, 23-dione (1), 24, 25, 26, 27-tetranortirucall-7-ene-3-oxo-23(21)-lactone (2), taraxerone (3), taraxerol (4) and b-sitosterol (5). Among them, compound 1 was a new triterpenoid, compounds 3-5 were firstly obtained from this plant; compound 2, an tetranortriterpenoid, was firstly isolated from natural sources, and its NMR data were assigned for the first time. Moreover, the D7-bond and the Me-14 in compound 2 were never changed, which has never been found in other tetranortriterpenoids. And the biosynthetic pathway of tetranortriterpenoid was further discussed.

Isolation, characterization and crystal structure of natural eremophilenolide from Ligularia sagitta

A new eremophilenolide 1beta, 10beta-epoxy-6beta-acetoxy-3beta-angeloyloxy-8beta-hydrox y-eremophil-7(11)-en-8, 12alpha-olide (1), together with liguhodgsonal (2), esculetin (3) and beta-sitosterol (4), was isolated from the aerial parts of Ligularia sagitta. The structure of the new constituent (1) was elucidated by spectroscopic methods and confirmed by single-crystal X-ray diffraction.