五枫藤、小驳骨和川西茶藨的化学成分研究

八月瓜属植物五枫藤(Holboellia latifolia Wall.)和驳骨草属植物小驳骨(Gendarussa vulgaris Nees)均为药用植物, 前者化学成分研究不深入, 后者的化学成分未见报道。川西茶藨(Ribes takare D. Don)为茶藨子属植物, 没有化学成分的报道。本论文对三个植物的化学成分和活性成分进行了研究, 主要通过色谱方法分离得到了48 个化合物, 采用波谱分析或与已知标准品对照等手段鉴定了它们的结构, 其中有1 个新的原小檗碱类化合物和3 个新的联苯类化合物,发现了具有细胞毒活性和α-葡萄糖苷酶抑制活性的化合物。1、从五枫藤地上部分的95%乙醇提取物中分离得到了12 个化合物: 五加苷K (1)、hederagenin 3-O- α-L-rhamnopyranosyl-(1→2)- α-L-arabinopyranoside (2)、β-萘乙酸(3) 、3-O-α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→3)]-α-L-arabinopyranosyl oleanolic acid 28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (4) 、3-O- α-L-rhamnopyranosyl-(1→2)-O- β- D-glucopyranosyl-(1→2)- α-L-arabinopyranosyl oleanolic acid (5) 、3-O-( β-D-glucopyranosiduronic acid)-oleanolic acid 28-O- β-D-glucopyranoside (6)、lup-20(29)-en-3-one (7)、lupeol (8)、β-谷甾醇(9)、齐墩果酸(10)、乌苏酸(11)、β-胡萝卜苷(12)。化合物1 对Lu-06、N-04 和Bre-04 癌细胞株的GI50 分别是0.77µg/mL、1.26 µg/mL 和1.55 µg/mL, 化合物2 对N-04 癌细胞株的GI50 为2.44 µg/mL。2、从小驳骨地上部分的95%乙醇提取物中分离得到了1 个原小檗碱类新化合物13-hydroxyl gusanlung A (25), β-谷甾醇(9)、齐敦果酸(10)、β-胡萝卜苷(12)、棕榈酸(1-)甘油酯(13)、棕榈酸(14)、阿苯哒唑(15)、阿苯哒唑砜(16)、阿苯哒唑亚砜(17)、aurantiamide acetate (18)、华良姜素(19)、芫花素(20)、(-)-丁香树酯醇(21)、gusanlung B (22) 、eupteleasaponinsⅤ acetate (23)、gusanlungA (24)、刺五加苷E (26)、岩白菜素(27)、咖啡酸(28)。化合物25 对肝癌细胞株(HepG2) 的GI50 为2.08 µg/mL。3、从川西茶藨地上部分的95%乙醇提取物中分离鉴定了22 个化合物: β-谷甾醇(9) 、β- 胡萝卜苷(12) 、O-acetyloleanolic aldehyde (29),4,7,8-trimethoxy-2,3-methylenedioxydibenzofuran (30) 、3', 5-dimethoxy-3, 4-methylenedioxybiphenyl (31) 、桦木醇(32) 、6,7-dimethoxy-1-methyl-3,4-dihydroquinolin-2-one (33)、3'-hydroxy-5-methoxy-3,4-methylenedioxybiphenyl (34) 、7-hydroxy-4,8-dimethoxy-2,3-methylenedioxydibenzofuran (35)、桦木醛(36)、没食子酸(37) 、6β- 羟基-4- 烯-3- 酮- 豆甾醇(38) 、5α, 8α-epidioxy-(22E,24R)-ergosta-6, 22-dien-3β-ol (39)、verrucofortine (40)、6-methoxycalpogoniumisoflavone A (41)、2-羟基二苯甲酮(42)、桦木酸(43), 3, 5-二甲氧基苯甲酸-4-O-β-D-吡喃葡萄糖苷(44)、洋芹素(45)、刺槐素(46)、水杨酸(47)、洋芹素-5-O- β-D-葡萄糖苷(48), 化合物30、31 和35 为新的联苯化合物。化合物30的α-葡萄糖苷酶抑制率为10.2% (1.00 mg/mL); 化合物35 的抑制率为17.2% (1.00mg/mL)。4、综述了1960 年以来原小檗碱类化合物药理活性研究进展。 Plants Holboellia latifolia Wall and Gendarussa vulgaris Nees, are used as folkmedicine. Ribes takare D. Don belongs to the genus Ribes. The three plants have notbeen chemically studied in detail. Chemical and bioactive study of three plants led tothe isolation of 48 compounds by chromatography. Their structures were elucidatedon the basis of spectroscopic evidence or comparison with authentic samples. Amongthe 48 componds isolated one protoberberine alkaloid and three biphenyls are newones. Cytotoxic and α-glucosidase inhibitory compounds had been found.1. Twelve compounds were isolated from the 95% ethanol extract of the aerial partof H. latifolia Wall. They were characterized as fellow: eleutheroside K (1),hederagenin-3-O- α-L-rhamnopyranosyl-(1→2)- α-L-arabinopyranoside (2),2-naphthyl acetic acid (3),3-O-α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→3)]-α-L-arabinopyranosyl oleanolic acid 28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (4), 3-O- α-L-rhamnopyranosyl-(1→2)-O- β- D-glucopyranosyl-(1→2)- α-L-arabinopyranosyl oleanolic acid (5),3-O-( β-D-glucopyranosiduronic acid)-oleanolic acid-28-O- β-D-glucopyranoside (6),lup-20(29)-en-3-one (7), lupeol (8), β-sitosterol (9), oleanolic acid (10), ursolicacid (11), and β-daucosterol (12). Compound 1 showed moderate cytotoxicity againstLu-06 (GI50, 0.77 µg/mL), N-04 (GI50, 1.26 µg/mL) and Bre0-4 (GI50=1.55 µg/mL)and compound 2 showed moderate cytotoxicity against N-04 (GI50=2.44 µg/mL).2. A new protoberberine alkaloid, 13-hydroxyl gusanlung A (25), was isolated fromthe aerial part of Gendarussa vulgaris Nees, together with β-sitosterol (9), oleanolicacid (10), β-daucosterol (12), glycerol monopalmitate (13), palmific acid (14),albendazole (15), albendazole sulphone (16), albendazole sufloxide (17), aurantiamideacetate (18), kumatakenin (19), genkwanin (20), (-)-syringaresinol (21), gusanlung B(22), eupteleasaponinsⅤ acetate (23), gusanlung A (24), eleutheroside E (26),bergenin (27) and caffeic acid (28). Compound 25 showed cytotoxicity against HepG2 cells (GI50, 2.08 µg/mL).3. Phytochemical study of the Ribes takare D. Don led to the isolation of three newbiphenyls, 4,7,8-trimethoxy-2,3-methylenedioxydibenzofuran (30), 3', 5-dimethoxy-3,4-methylenedioxybiphenyl (31) and 7-hydroxy-4,8-dimethoxy-2,3-methylenedioxydibenzofuran (35), along with nineteenknown compounds, β-sitosterol (9), β-daucosterol (12), O-acetyloleanolic aldehyde(29), betulin (32), 6,7-dimethoxy-1-methyl-3,4-dihydroquinolin-2-one (33),3'-hydroxy-5-methoxy-3, 4-methylenedioxybiphenyl (34), betulinic aldehyde (36),gallic acid (37), stigmast-4-en-6β-ol-3-one (38), 5α, 8α-epidioxy-(22E, 24R)-ergosta-6,22-dien-3β-ol (39), verrucofortine (40), 6-methoxycalpogonium isoflavone A (41),2-hydroxybenzophenone (42), betulinic acid (43), 3,5-dimethoxygallic acid-4-O- β-D-glucopryranoside (44), apigenin (45), acacetin (46), salicylic acid (47) andapigenin-5-O- β-D-glucopryranoside (48). α-Glucosidase inhibitory rates ofcompound 30 and 35 were respectively 10.2% and 17.2% at a concentration of 1.00 mg/mL).4. Pharmacological activities of protoberberines were summarized.

非粮原料燃料乙醇发酵关键技术的研究

生物质燃料乙醇是一种高度清洁的交通液体燃料，是减少温室气体排放，缓解大气污染的最佳技术选择。以非粮原料生产燃料乙醇可以在进行能源生产的同时保证粮食安全，有利于产业的可持续发展。在众多的非粮原料中，甘薯是我国开发潜力最大的生物质能源作物之一。我国占世界甘薯种植总面积和产量的90％。同时，甘薯的单位面积燃料乙醇产量远大于玉米和小麦。其成本是目前酒精中最低廉的，因此利用甘薯生产乙醇是发展生物质燃料乙醇的首要选择。目前采用薯类全原料主要采用分批发酵生产乙醇，其技术水平低，发酵强度低，一般在0.7－2.5g/（L•h），乙醇浓度低，甘薯发酵乙醇为6－8％(v/v)，能耗高，环境负荷大，污染严重。针对上述问题，本文从菌株选育、原料预处理、中试放大、残糖成分分析等方面进行研究。 为了研究乙醇发酵生产规模扩大过程中，大型发酵罐底部高压条件下，CO2对酵母乙醇发酵的影响，我们通过CO2 加压的方法进行模拟试验，研究结果表明，发酵时间随压强的升高而逐渐延长，高压CO2 对乙醇发酵效率影响不大，在0.3 MPa 以下时，发酵效率均可达到90%以上。高压CO2 对发酵的抑制作用是高压和CO2 这两个因素联合作用的结果。高压CO2 条件下，酵母胞外酶和胞内重要酶类的酶活均表现出特征性。0.2 MPa 下，酶活性的变化趋势和0.1 MPa 条件下的较为一致。而0.3 MPa 下的酶活变化趋势与0.4 MPa 下的酶活更为接近。通过全基因表达分析发现在CO2 压力为0.3 MPa 下，乙醇发酵途径中多个基因表达量下调，同时海藻糖合成酶和热激蛋白基因表达量上调。 筛选耐高温的乙醇酵母菌株能够解决糖化温度和发酵温度不协调的矛盾，实现真正意义上的边糖化边发酵。高温发酵还能够降低发酵时的冷却成本，实现乙醇的周年生产。本研究筛选出一株高温发酵菌株Y-H1，进而我们对该菌株的胞外酶和胞内乙醇代谢重要酶类的酶活性进行了分析。结果表明Y-H1 能够在40 ℃条件下正常进行乙醇发酵，发酵33h，最终乙醇浓度达到10.7%（w/w），发酵效率达到90%以上。同时发酵液最终pH 在3.5 左右，显示菌株具有一定的耐酸性能力。同时观察到40 ℃下，菌株的胞外酶和胞内乙醇代谢重要酶类的酶活性发生了变化，乙醇发酵途径中关键酶基因表达下调，而海藻糖合成酶与热激蛋白基因表达量上调，这些结果为进一步研究酵母菌耐热调控机理提供了依据。 糖蜜是一种大规模工业生产乙醇的理想原料，本研究利用选育高浓度乙醇发酵菌株结合配套的发酵稳定剂，研究了糖蜜高浓度乙醇发酵情况。结果表明采用冷酸沉淀预处理糖蜜溶液，采用分批补料的发酵方式，乙醇浓度最高达到了10.26% (w/w)，发酵时间为42 h。同时观察到在糖蜜发酵中，乙醛含量与乙醇浓度存在一定的相关性。 快速乙醇发酵对于缩短乙醇生产周期、降低乙醇生产成本、减少原料腐烂损失具有重要意义。本研究诱变和筛选得到了一株快速乙醇发酵菌株10232B。在优化后的发酵条件下，采用10L 发酵罐进行分批乙醇发酵，经过18h,乙醇的最终浓度达到88.5g/L,发酵效率93.6%，平均乙醇生产速度达到4.92 g/L/h。此菌株在保持较高乙醇生产浓度的同时，拥有快速生产乙醇的能力，适合作为快速乙醇发酵生产菌种。 由于鲜甘薯具有粘度大的特点，传统液化糖化处理很难在短时间内充分糖化原料；高粘度的醪液也难以进行管道输送，容易堵塞管路；同时，也会降低后续的乙醇发酵效率。 本文采用了快速粘度分析法对鲜甘薯糊化粘度特性进行了分析，进而对预处理条件进行了研究，在最佳预处理条件下，糖化2h 后，醪液葡萄糖值最高可达99.3，粘度4.5×104 mPa.s，而采用传统糖化工艺，醪液DE 值仅为85.8，粘度大于1.0×105 mPa.s。 此预处理方法也可用于快速糖化不加水的醪液。后续的乙醇发酵试验表明，通过此预处理方法获得的糖化醪液对乙醇发酵无负面影响。 在前期已实现了实验室水平的鲜甘薯燃料乙醇快速乙醇发酵基础上，进一步将发酵规模扩大到500L，在中试水平上对甘薯乙醇发酵进行了研究。结果表明在500L 中试规模，采用边糖化边发酵（SSF）工艺，在料液比为3∶1，发酵醪液最高粘度为6×104mPa.s 条件下，发酵37h，乙醇浓度达到了12.7%（v/v），发酵效率91%，发酵强度为2.7 g/（L•h）。与目前国内的薯类乙醇发酵生产技术水平具有明显的优越性。 为研究甘薯、木薯乙醇发酵中残糖的组成，采用了高效液相色谱—蒸发光散射检测法，对乙醇发酵残糖进行了分析。结果表明，甘薯、木薯乙醇发酵残糖均为寡聚糖，主要由葡萄糖、木糖、半乳糖、阿拉伯糖和甘露糖构成。随着发酵时间延长，寡聚糖中的葡萄糖、半乳糖、甘露糖可被缓慢的水解释放。提高糖化酶量仅在一定程度上降低残糖，过量的糖化酶反而会导致残糖增加。同时发现3, 5-二硝基水杨酸法不能准确测定甘薯、木薯乙醇发酵中的残总糖含量。进一步筛选了两株残糖降解菌株，对甘薯乙醇发酵残糖的降解利用率均达到了40%以上，而且还能显著降低发酵醪液粘度。经形态学和rRNA ITS 序列分析，确定这两株菌分别属于为木霉属和曲霉属黑曲霉组。 通过对以甘薯原料为代表的非粮原料发酵技术研究开发，以期形成乙醇转化率高，能耗低，生产效率高、季节适应性好，原料适应性广，经济性强，符合清洁生产机制的燃料乙醇高效转化技术，为具有我国特色的燃料乙醇发展模式提供技术支持。 Sweet potato is one of the major feedstock for the fuel ethanol production in China. The planting area and the yield in China take 90% of the world. Sweet potato is an efficient kind of energy crops. The energy outcome per area is higher than corn or wheat. And the manufacture cost of ethanol is the lowest, compared with corn and wheat. So sweet potato is the favorable crop for the bioethanol production in China. However, the low-level fermentation technology restricts the development of ethanol production by sweet potato, including slow ethanol production rate, low ethanol concentration and high energy cost. To solve these problems, we conducted research on the strain breeding, pretreatment, pilot fermentation test and residual saccharides analysis. To study the impact of hyperbaric condition at bottom of the large fermentor on yeast fermentation, high pressure carbon dioxide (CO2) was adopted to simulate the situation. The results showed that the fermentation was prolonged with the increasing pressure. The pressure of CO2 had little impact on the ethanol yield which could reach 90% under the pressure below 0.3 MPa. The inhibition was combined by the high pressure and CO2. Under the high CO2 pressure, the extracellular and important intracellular enzyme activities were different from those under normal state. The changes under 0.1 MPa and 0.2 MPa were similar. The changes under 0.3 MPa were closer to those under 0.4 MPa. The application of thermotolerance yeast could solve the problem of the inconsistent temperature between fermentation and saccharificaton and fulfill the real simultaneous saccharification and fermentation. And it could reduce the cooling cost. A thermotolerance strain Y-H1 was isolated in our research. It gave high ethanol concentration of 10.7%（w/w）at 40 ℃ for 33 h. The ethanol yield efficiency was over 90%. At 40 ℃, the extracellular and important intracellular enzyme activities of Y-H1 showed the difference with normal state, which may indicate its physiological changes at the high temperature. Molasses is another feedstock for industrial ethanol production. By our ethanol-tolerance strain and the regulation reagents, the fermentation with high ethanol concentration was investigated. In fed-batch mode combined with cold acid deposition, the highest ethanol concentration was 10.26% (w/w) for 42h. The aldehyde concentration in fermentation was found to be related to ethanol concentration. The development of a rapid ethanol fermentation strain of Zymomonas mobilis is essential for reducing the cost of ethanol production and for the timely utilization of fresh material that is easily decayed in the Chinese bioethanol industry. A mutant Z. mobilis strain, 10232B, was generated by UV mutagenesis. Under these optimized conditions, fermentation of the mutant Z. mobilis 10232B strain was completed in just 18 h with a high ethanol production rate, at an average of 4.92 gL-1h-1 per batch. The final maximum ethanol concentration was 88.5 gL-1, with an ethanol yield efficiency of 93.6%. This result illustrated the potential use of the mutant Z. mobilis 10232B strain in rapid ethanol fermentation in order to help reduce the cost of industrial ethanol production. As fresh sweet potato syrup shows high viscosity, it is hard to be fully converted to glucose by enzymes in the traditional saccharification process. The high-viscosity syrup is difficult to be transmitted in pipes, which may be easily blocked. Meanwhile it could also reduce the later ethanol fermentation efficiency. To solve these problems, effects of the pretreatment conditions were investigated. The highest dextrose equivalent value of 99.3 and the lowest viscosity of 4.5×104 mPa.s were obtained by the most favorable pretreatment conditions, while those of 85.8 and over 1.0×105 mPa.s was produced by traditional treatment conditions. The pretreatment could also be applied on the material syrup without adding water. The later experiments showed that the pretreated syrup had no negative effect on the ethanol fermentation and exhibited lower viscosity. The fuel ethanol rapid production from fresh sweet potato was enlarged in the 500L pilot scale after its fulfillment on the laboratory level. The optimal ratio of material to water was 3 to 1 in 500L fermentor. With low-temperature-cooking (85 ℃) using SSF, the Saccharomyces cerevisiae was able to produce ethanol 97.44 g/kg for 37h, which reached 92% of theoretical yield. The average ethanol production rate was 4.06 g/kg/h. And the maximum viscosity of syrup reached 6×104mPa.s. The results showed its superiority over current industrial ethanol fermentation. The compositions of the residual saccharides in the ethanol fermentation by sweet potato and cassava were analyzed by high performance liquid chromatography coupled with evaporative light-scattering detector. The results showed that all the residual saccharides were oligosaccharides, mainly composed of glucose, xylose, galactose, arabinose and mannose. The glucose, galactose and mannose could be slowly hydrolyzed from oligosaccharides in syrup during a long period. To increase the glucoamylase dosage could lower the residual saccharides to a certain extent. However, excess glucoamylase dosage led to more residual saccharides. And the method of 3, 5-dinitrosalicylic acid could not accurately quantify the residual total saccharides content. Two residual saccharides degrading strains were isolated, which could utilize 40% of total residual saccharide and lower the syrup viscosity. With the analysis of morphology and internal transcribed spacer sequence, they were finally identified as species of Trichoderma and Aspergillus niger.

Flow-through room temperature phosphorescence optosensing for the determination of lead in sea water

The chelates formed between the heavy metal ion Pb(II) and the reagents 8-hydroxy-5-quinolinesulphonic acid, 8-hydroxy-7-quinolinesulphonic acid and 8-hydroxy-7-iodo-5-quinolinesulphonic acid exhibit strong room temperature phosphorescence (RTP) if retained on the surface of anion exchange resin beads. Based on the on-line formation, in a flow-injection system, of such RTP lead chelates and their transient immobilization on an anion exchange resin, three flow-through optosensing systems are investigated for lead in sea water. Optimum experimental conditions and the analytical performance characteristics of the three optosensors are discussed. Relative standard deviations (RSDs) of the order of 3% are typical at 100 ng ml−1 Pb(II) and the active sensing phases can easily be regenerated by passing 500 μl of 6 M hydrochloric acid. A lead(II) detection limit of 0.1 ng ml−1 (3×background SD, for 2 ml sample injection volumes) was achieved for the optosensor based on 8-hydroxy-7-quinolinesulphonic acid. Possible interferences present in sea water, including cations and anions which could affect the sensor response, are discussed in detail. Finally, the selected RTP flow-through optical sensor has been successfully tested for the determination of lead in sea water at a few ng ml−1.

A Biodegradable Diblcok Copolymer Poly(ethylene glycol)-block-poly(L-lactide-co-2-methyl-2-carboxyl-propylene carbonate): Docetaxel and RGD Conjugation

A diblcok copolymer monomethoxy poly (ethylene glycol)-block-poly(L-lactide-co-2-methyl-2-carboxyl-propylene carbonate) (MPEG-b-P(LA-co-MCC)) was obtained by copolymerization of L-lactide (LA) and 2-methyl-2-benzoxycarbonyl-propylene carbonate (MBC) and subsequent catalytic hydrogenation. The pendant carboxyl groups of the copolymer MPEG-b-P(LA-co-MCC) were conjugated with antitumor drug docetaxel and tripeptide arginine-glycine-aspartic acid (RGD), respectively.

基质辅助激光解吸电离飞行时间质谱表征细胞色素C

A matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF—MS) technique was used for analysis of moleculear weight of cytochrome C.The effects of three kinds of matrix,such as 2,5-dihydroxybenzoic acid(DHB),a-cyano-4-hydroxycinnamic acid(a-CHC) and sinapinic acid(SA),were used to compared and a suitable a-CHC was found.Experimental data showed that this method was properable to analysis of the congeneric biochemical samples.

Analysis of poly (arylene phosphonate) cyclic oligomer by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MAIDI-TOF-MS) was used for analysis of poly(arylene phosphonate) cyclic oligomers. A comparison was made by using 1,8,9-dithranol, 2,5-dihydroxybenzoic acid and retinoic acid as the matrix. The result showed that the retinoic acid produced the strongest ion signals under the conditions used. Different salts of metals were used as the cationization agents to examine the effect on the cyclic oligomers. It was found that the salts could produce metal-cyclic oligomer cation spectra and lithium was the stronger one than those of silver so, the suitable matrix and cationization agent for the new cyclic oligmer were obtained. They were very effective for the analysis of poly(arylene phosphonate) cyclic oligomer.

Investigation of a series of synthetic cationic porphyrins using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was used to study a series of synthetic cationic porphyrins as the perchlorate and bromide salts. This work presents the analytical results for the porphyrins obtained using 2,5-dihydroxybenzoic acid (DHB) and 1,8,9-anthratriol as matrices. The selective use of matrix affects ion formation from these porphyrins. By using DHB as the matrix, we not only observed [M - nCIO(4)](+) (n = 1-4) ions, but also obtained [2M - nCIO(4)](+) (n = 2-7) ions from the synthetic cationic porphyrins. The space volume of the side chains (R groups) and the nature of the anions (Br- or CIO4-) affected the relative importance of monomeric and dimeric ions of the porphyrin. The possible mechanisms of desorption and ionization of these cationic porphyrins were also considered in this study. MALDI-TOFMS proved to be a very useful method for obtaining structural information on these synthetic cationic porphyrins. Copyright (C) 1999 John Whey & Sons, Ltd.

Matrixassisted laser desorption/ionization mass spectral study of saccharides

Matrixassisted laser desorption/ionization (MALDI) mass spectra of saccharides with three common matrixes were studied here. It is shown that Na+ and K+ play important roles in the determination of oligasaccharide molecule weight and the molecular weights (MW) of glucans(dextran) with MW more than 10 000 is determined successfully with the help of column chromatography, By comparing the effects of three matrixes in saccharide analysis and comparing positive-ion and negative-ion matrixassisted laser desorption/ionization mass spectra of oligo- and polysaccharides, the most suitable matrix for saccharide analysis, 2,5-dihydroxylbezonic acid (DHB), is selected and the ion formation processes of saccharides under matrix-assisted laser adsorption/ionization condition are clarified.

Characterization of cyclic (aryletherketone)s by matrix-assisted laser desorption ionization time of flight mass spectrometry

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was used to identify cyclic(aryl ether ketone) oligomers, using 2,5-dihydroxybenzoic acid as a matrix, and Na+ and K+ as cationization agents, The existence of different ring-sized cyclic oligomers up to 9 and their distribution were determined and compared with GPC results, The results indicated that MALDI-TOF MS was a powerful and rapid analytical tool for the cyclic oligomers.

Structure/permeability and permselectivity relationship of polyetherimides from 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride .2.

Gas permeability coefficients of a series of aromatic polyetherimides, which were prepared from 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA) with various aromatic diamines, to H-2, O-2 and N-2 have been measured under 7 atm and at the temperature range 30-100 degrees C. A significant change in the permeability and permselectivity resulting from the systematic variation in chemical structure of the polyetherimides was found. Among the polyetherimides, that were prepared from phenylenediamine and methyl substituted phenylenediamines, the increase of permeability is accompanied by a decrease of permselectivity. The polyetherimides that were prepared from 3,5-diaminobenzoic esters have lower permselectivity than the others. However, the polyetherimide from 3,5-diaminobenzoic acid possesses much higher permselectivity than the others due to cross-linking. Copyright (C) 1996 Elsevier Science Ltd

COMPARATIVE-STUDY OF KALMAN FILTERING, SYNCHRONOUS EXCITATION AND NUMERICAL DERIVATIVE TECHNIQUES IN FLUOROMETRY

The performance of Kalman filtering, synchronous excitation and numerical derivative techniques for the resolution of overlapping emission spectra in spectrofluorimetry was studied. The extent of spectrum overlap was quantitatively described by the separation degree D(s), defined as the ratio of the peak separation to the full width at half-maximum of the emission spectrum of the interferent. For the system of Rhodamine B and Rhodamine 6G with a large D(s) of about 0.4, both Kalman filtering and synchronous techniques are able to resolve the overlapping spectra well and to give satisfactory results while the derivative spectra are still overlapped with each other. Moreover, the sensitivities are greatly decreased in derivative techniques. For more closely spaced spectra emitted by the complexes of Al and Zn with 7-iodo-8-hydroxyquinoline-5-sulphonic acid (Ferron)-hexadecyltrimethylammonium bromide, the synchronous excitation technique cannot completely separate the overlapping peaks, although it increases the separation degree from 0.25 in the conventional spectra to 0.37 in the synchronous spectra. On the other hand, Kalman filtering is capable of resolving this system. When the Al/Zn intensity ratio at the central wavelength of Al was > 1, however, the accuracy and precision of the estimates for Zn concentration produced by the Kalman filter became worse. In this event, the combination of synchronous excitation and Kalman filtering can much improve the analytical results.

Bromophenols from the red alga Rhodomela confervoides

Six new bromophenols, 3-bromo-4,5-bis(2,3-dibromo-4,5-dihydroxybenzyl)pyrocatechol (1), 2,2',3-tribromo-3',4,4',5-tetrahydroxy-6'-hydroxymethyldiphenylmethane (2), 2,2',3-tribromo-3',4,4',5-tetrahydroxy-6'-ethyloxymethyldiphenylmethane (3),(+/-)-2-methyl-3-(2,3-dibromo-4,5-dihydroxyphenyl)propylaldehyde (4), (+/-)-2-methyl-3-(2,3-dibromo-4,5-dihydroxyphenyl)propylaldehyde dimethyl acetal (5), and 3-bromo-4,5-dihydroxybenzoic acid methyl ester (6), together with eight known bromophenols, 3-bromo-4,5-dihydroxybenzaldehyde (7), 2,3-dibromo-4,5-dihydroxybenzyl alcohol (lanosol, 8), 2,3-dibromo-4,5-dihydroxybenzyl methyl ether (9), 2,3-dibromo-4,5-dihydroxybenzyl ethyl ether (10), 2,3-dibromo-4,5-dihydroxybenzylaldehyde (11), bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (12), 3-bromo-4-(2,3-dibromo-4,5-dihydroxybenzyl)-5-methoxymethylpyrocatechol (13), and 2,2',3,3'-tetrabromo-4,4',5,5'-tetrahydroxydiphenyl methane (14), were isolated from the red alga Rhodomela confervoides. Their structures were elucidated by chemical and spectroscopic methods including IR, HRFABMS, and 1D and 2D NMR techniques.

Bromophenol derivatives from the red alga Rhodomela confervoides

Eight new bromophenol derivatives, 2,3-dibromo-4,5-dihydroxybenzyl methyl sulfoxide (1), 4-(2,3-dibromo-4,5-dihydroxyphenyl)-3-butene-2-one (2), 2-(3-bromo-5-hydroxy-4-methoxyphenyl)-3-(2,3-dibromo-4,5-dihydroxyphenyl)propionic acid (3), 2-(3-bromo-5-hydroxy-4-methoxyphenyl)-3-(2,3-dibromo-4,5-dihydroxyphenyl)propionic acid methyl ester (4), 2-phenyl-3-(2,3-dibromo-4,5-dihydroxyphenyl)propionic acid (5), 4'-methoxy-2",3',3"-tribromo-4",5',5"-trihydroxydiphenylacetic acid (6), and 3-bromo-5-hydroxy-4-methoxyphenylacetic acid (7) and its methyl ester (8), together with a known bromophenol, 3-bromo-5-hydroxy4-methoxybenzoic acid (9), were isolated from the red alga Rhodomela confervoides. Their structures were elucidated by spectroscopic methods including IR, EIMS, FABMS, ESIMS, HRFABMS, HRESIMS, 1D and 2D NMR, and single-crystal X-ray structure analysis. Compounds 1-4, 8, and 9 were found inactive against several human cancer cell lines and microorganisms.

A new brominated phenylpropylaldehyde and its dimethyl acetal from red alga Rhodomela confervoides

A new brominated phenylpropylaldehyde and its dimethyl acetal together with a new natural brominated phenol were isolated from Rhodomela confervoides. Their structrues were elucidated as 2-methyl-3-(2,3-dibromo-4,5-dihydroxyphenyl)propylaldehyde, 2-methyl-3-(2,3-dibromo-4,5-dihydroxyphenyl) propylaldehyde dimethyl acetal and 3-bromo-4,5-dihydroxybenzoic acid methyl ester by spectroscopic techniques including IR, HRFABMS, ID and 2DNMR experiments.

Adsorption and Corrosion Inhibition Behavior of Mild Steel by One Derivative of Benzoic-Triazole in Acidic Solution

A newly synthesized benzoic-triazole derivative 3,5-dimethylbenzoic acid [1,2,4]triazol-l-ylmethyl ester (DBT) was investigated as a corrosion inhibitor of mild steel in 1 M HCl solution using weight loss measurements, potentiodynamic polarization, SEM, and EIS methods. The results revealed that DBT was an excellent inhibitor, and the inhibition efficiencies obtained from weight loss and electrochemical experiments were in good agreement. Using the potentiodynamic polarization technique, the inhibitor was proved to have a mixed-type character for mild steel by suppressing both anodic and cathodic reactions on the metal surface. The number of water molecules (X) replaced by a molecule of organic adsorbate was determined from the Flory-Huggins, Dhar-Flory-Huggins, and Bockris-Swinkels substitutional adsorption isotherms applied to the data obtained from the gravimetric experiments performed on a mild steel specimen in 1 M HCl solution at 298 K.