Analysis of paralytic shellfish toxins in Aphanizomenon DC-1 from Lake Dianchi, China

Lake Dianchi is in Yunnan Province in southwestern China. In recent years, significant cyanobacterial blooms have occurred in this lake nearly every year because of eutrophication. Monitoring data for the past 5 years acquired by our research group showed that phytoplankton composition alternated between species of Microcystis sp. during warm seasons and those of Aphanizomenon sp. during cool seasons. In March 2003, when phytoplankton composition was highly dominated by Aphanizomenon sp., samples were taken from the lake for toxin detection and immediate strain isolation. A mouse bioassay with extracts from the lyophilized field material showed obvious intoxication from paralytic shellfish poisons (PSPs), and all mice died within 30 min. Further analysis of both field and isolated algal strain Aphanizomenon DC-1 by the postcolumn HPLC-FLD method confirmed its PSP-producing ability The analogues found in the extracts from the field material were neoSTX, dcSTX, and dcGTX3, with contents of 2.279, 1.135, and 0.547 ng/mg DW, respectively. Under laboratory culture condition, toxin content in the Aphanizomenon strain DC-1 varied greatly during different growth phases, with two peaks: in the early-exponential and late-stationary growth phases. When the culture grew at a relatively high rate during the mid- to late-exponential growth phase, toxin content declined gradually. Moreover, the types of toxin in the DC-1 strain varied greatly during a single culture cycle. The HPLC results showed that dcSTX was the only toxin isomer detected throughout the culture period, and its level remained stable. On the other hand, dcGTX2 and GTX4 were the major toxins during the early-exponential and stationary phases, respectively. This article presents the first data on the identification and detection of paralytic shellfish toxins from cyanobacteria in Lake Dianchi. As far as we know, this is also the first report of this type of toxin in inland water bodies in China. Our study indicates the threat associated with PSP toxins in Lake Dianchi and suggests that necessary measures and programs for control are urgently needed to prevent the spread of toxic cyanobacterial blooms. (c) 2006 Wiley Periodicals, Inc.

钼体系催化合成1,2－聚丁二烯的研究

本工作通过较系统地研究Ziegler-Natta型钼催化体系对丁二烯聚合的催化作用，发现一类活性很高的钼催化剂。此类催化剂以无毒，资源丰富的加氢汽油为溶剂，活性已接近工业化的Ni、Co、Ti等体系。同时，本工作又找到了大幅度调节聚合物分子量和链结构的方法，发现了具有活性聚合特点的钼催化体系，初步考察了钼体系催化丁二烯聚合的动力学行为；并利用红外光谱，~(13)C-NRM、X-射线衍射和热分析等方法研究了所得聚合物的链结构和聚集态结构，对聚合物的基本性能也进行了初步考察，发现所得聚合物的一些基本性能超过天然橡胶。此类高活性钼催化剂由MoCl_4OR和(i-Bu)_2AlOAr组成，R为C_(8-18)烷基，Ar为芳基。本催化体系在70 ℃下催化丁二烯聚合时，催化剂用量为Mo/J摩尔比等于4 * 10~(-5)时，转化率可达78％。本体系聚合物分子量可用烯丙基卤等调节，其中烯丙基碘的效果最好。在Mo/J = 8 * 10~(-5)时，烯丙基碘/Mo摩尔比为0.1时即可使聚合物分子量下降约50万；烯丙基碘/Mo摩尔比为10时，聚合物重均分子量即小于20万（不加烯丙基碘为270万）。本体系聚合物分子量分布很窄，聚合温度为30 - 70 ℃时，_W/_n为1.5-2.0；_W/_n与聚合温度呈直线关系，利用外推法估计和动力学考察，本体系在－18 ℃左右有可能引发活性聚合。本体系聚丁二烯含有85％以上1,2－链节，其1，2-链节含量也可以用某些极性添加剂来调节。利用烯丙基碘做调节剂，可制得1,2－链节含量高达98％的聚丁二烯。烯丙基碘还可以调节聚合物链节的立体构型和序列分布；随着烯丙基碘用量的增加，间同1,2－链节增多，全同和无规1,2－链节减少，序列分布的有规性增加，链结构趋于规整。根据动力学初步研究结果，本体系催化丁二烯聚合的速度对单体浓度呈一级关系，表现活化能为17.07千卡／摩卡，催化剂利用率为4％，链增长速度常数为: k_(p30℃) = 40 (升／摩尔·分，下同), k_(p40℃) = 97, k_(p50℃) = 267, k_(p60℃) = 508, k_(p70℃) = 12077。本体系聚合物在烯丙基碘/Mo摩尔比小于2时，无论静态或拉伸下均为无定型；烯丙基碘/Mo摩尔比大于2而小于8时，静态下为无定型，而拉伸时产生结晶，与天然橡胶类似；烯丙基碘／Mo摩尔比大于8时，静态下亦有一定程度的结果。

键合法制备硅基1.55μm InP-InGaAsP量子阱激光器

在硅基上成功地制备出了1．55μm InP-InGaAsP量子阱激光器．设计并生长了适合于键合的量子阱激光器结构材料，通过直接键合技术，将Si衬底与InP-InGaAsP外延片键合到一起．剥离去掉InP衬底后，在5～6μm的薄膜上制备出20μm条形边发射激光器．室温下，阈值电流160mA（电流密度为2．7kA／cm^2），功率可达10mW以上（在约350mA电流下），实现了1．55μm长波长边发射激光器与Si的集成．目前，该结果国际上还未见报道．

具有环氧化酶-2选择性抑制活性的多取代蒽醌的合成

1-甲基-2-甲氧羰基-3, 6, 8-三羟基-7-甲氧基蒽醌是从唐菖蒲干球茎中分离到的具有环氧化酶-2选择性抑制活性的多取代蒽醌类化合物。本文试图合成该化合物，实现了其类似物的合成，同时发现了几个未见报道的反应。 1．通过Diels-Alder 反应合成了关键中间体——3-甲基-5-羟基-1, 2, 4-苯三甲酸三甲酯，1-COOMe选择性水解产物与1, 2, 3-三甲氧基苯进行分子间Friedel-Crafts反应的产物再进行分子内Friedel-Crafts反应得到了目标产物的类似物1-甲基-2-甲氧羰基-3-羟基-6，7，8-三甲氧基蒽醌（路线1）。目标产物及其它类似物的合成正在进行中。 2．以乙酰乙酸甲酯和巴豆醛为原料，经过Michael加成、分子内的Aldol反应、芳香化、选择性甲酰化和还原反应，得到关键中间体2-甲基-3-羟甲基-6-甲氧基苯甲酸甲酯及其衍生物。通过该化合物与3，4，5-三甲氧基苯甲酸甲酯进行Friedel-Crafts烷基化反应得到了多取代的二苯基甲烷衍生物，拟进一步关环合成目标化合物（路线2）。 3．发现邻甲氧基苯甲酸甲酯中酯甲基可以被正丁基锂和仲丁基锂中烷基交换生成相应的酯，反应的机理不明确。当使用叔丁基锂时，得到的是邻甲氧基苯基叔丁酮，这个方法可以用来合成芳基叔丁酮类化合物。 4．以2-苄氧基-6-甲基苯甲酸甲酯为原料进行氯甲基化反应时，以苯和二氯乙烷作溶剂，发生了苄基的迁移和芳环的偶联，分别得到2，2'-二甲基-3，3'-二甲氧羰基-4，4'-二羟基联苯和2，2'-二甲基-3，3'-二甲氧羰基-4，4'-二羟基-5，5'-二苄基联苯。这是对称联苯合成的新方法。 5．水杨酸羟基邻对位的选择性甲酰化可以分别通过水杨酸和水杨酸甲酯用HMTA/CF3COOH来实现。 6．Lewis酸催化3，4，5-三甲氧基苄醇环化成1, 2, 3, 6, 7, 8, 11, 12, 13-nonamethoxyl-10,15-dihydro-5H-trbibenzo [a, d, g] cyclononene (NDTC)，产率(54%)高于已有方法（12%）。 Methyl 3,6,8-trihydroxy-7-methoxy-1-methylanthraquinone-2-carboxylate is a new COX-2 selective inhibitor isolated from Gladiolus gandavensis. Two strategies were investigated to synthesis this compound, in which some important reactions were discovered. 1. The key intermediate 5-hydroxy-3-methylbenzene-1,2,4-tricarboxylic acid 2,4-dimethyl ester was prepared via Diels-Alder reaction followed by selective hydrolysis of 1-COOMe. This compound was coupled with 1,2,3-trimethoxybenzene and the product undergo intramolecular Friedel-Crafts reaction to give methyl 3-hydroxy-5,6,7-trimethoxy-1-methylanthraquinone-2-carboxylate (1st route). The target compound and other analogues are being prepared with the same procedure. 2. The key intermediates methyl 3-hydroxymethyl-6-methoxy-2-methylbenzoate and its derivatives were prepared starting from crotonaldehyde and methyl acetoacetate via Michael addition, intramolecular aldol reaction, aromatization, formylation and reduction. The intermediates were coupled respectively with derivatives of gallic acid to give polysubstituted diphenylmethane. However, attempts to cyclize these compounds to the target compounds and analogues were not successful (2nd route). 3. In the process for ortho-lithiation of methyl 2-methoxybenzoate, the substrate converted respectively to n-butyl 2-methoxybenzoate and sec-butyl 2-methoxybenzoate when n-BuLi and sec-BuLi were used. However, tert-BuLi reacted with methyl 2-methoxybenzoate afford 2-methoxyphenyl tert-butyl ketone, which could be used to synthesize aryl tert-butyl ketones. 4. The transformtion of methyl 2-benzoxy-6-methylbenzoate to dimethyl 4,4'-dihydroxy-2,2'-dimethylbiphenyl-3,3'-dicarboxylate in benzene, and dimethyl 5,5'-dibenzyl-4,4'-dihydroxy-2,2'-dimethylbiphenyl-3,3'-dicarboxylate in 1,2-dichloroethane in the presence of ZnCl2 provides a new method for the synthesis of symmetric biphenyl. 5. The formylation of salicylic acid at C-5 and methyl 2-hydroxybenzoate at C-3 could be regioselectively realized by using HMTA/CF3COOH. 6. Racemic 1, 2, 3, 6, 7, 8, 11, 12, 13-nonamethoxyl-10, 15-dihydro-5H-trbibenzo [a, d, g] cyclononene was prepared via Lewis acids catalyzed trimerization of 3, 4, 5-trimethoxylbenzyl alcohol with yield (54%) higher than the reported procesure (12%).

~(179)Au的1/2[660](πi_(13/2))转动带

利用能量为 16 4— 180MeV的 3 5Cl束流 ,通过重离子核反应 14 9Sm(3 5Cl ,5n)研究了 179Au的高自旋态能级结构 .实验进行了γ射线的激发函数、X γ和γ γ t符合测量 .基于对实验测量结果的分析 ,首次建立了 179Au的 1 2 [6 6 0 ](πi13 2 )转动带 .结合已有的实验数据 ,着重讨论了奇AAu核中1 2 [6 6 0 ](πi13 2 )转动带的带头激发能随中子数的变化

1,2,4-三氯苯胁迫对萌发大豆种子中活性氧的影响

以盆栽法研究了不同浓度 1,2 ,4 三氯苯 (TCB)胁迫对萌发大豆种子中活性氧代谢的影响 .结果表明 ,10 0～ 30 0 μg·g-1TCB胁迫初期 (1～ 3天 )促使萌发大豆种子呼吸强度升高及其峰值提前出现 ,超氧阴离子自由基 (O2 - )及过氧化氢 (H2 O2 )的积累显著增加 ,同时伴随丙二醛 (MDA)含量升高 ,显示发生膜脂质过氧化作用 .TCB胁迫 1～ 6天使活性氧清除酶功能紊乱 ,其中过氧化物酶 (POD)活性升高 ,超氧化物岐化酶 (SOD)活性开始上升后转为下降 .在萌发大豆种子受TCB胁迫伤害过程中 ,活性氧代谢失衡造成的膜脂质过氧化将起着重要作用 .

1，2，4－三氯苯在土壤中的降解

在好氧和厌氧两种条件下研究了１，２，４－三氯苯的降解，结果表明，１，２，４－三氯苯的好氧降解和厌氧降解均遵循一级反应动力学在同样水分、温度及初始浓度条件下，１，２，４－三氯苯的好氧降解比厌氧降解迅速，其半衰期分别为１．８９～５．８６和５．０７～１９．０８ｄ土壤中１，２，４－三氯苯的初始浓度对于其降解也有显著影响，在０～１００μｇ·ｇ－１的范围内，浓度增高时，其降解加快，说明污染物浓度对降解的影响；在１０～３０℃范围内，温度增高导致降解过程加快，归因于温度升高对微生物酶活性的激活作用．

1.老年猴视皮层神经元对图形对比度的反应及其潜伏期特征; 2. 极低频磁场对脑功能的影响及眶额叶认知功能的研究

1.老年猴视皮层神经元对图形对比度的反应及潜伏期特征: 在正常衰老过程中人类的视觉功能受到严重影响，例如空间和时间对比度敏感性下降以及信息处理时间的延长。虽然部分视觉功能的退化与眼睛的光学系统老化有关，但是它并不能解释所有视觉功能的下降。此外，我们以前的研究和别人的研究结果都表明衰老过程中视觉中枢系统功能的改变可能是视觉功能下降的主要原因。因此，利用单位放电记录技术（single-unit recording technique），我们比较了年轻猕猴和老年猕猴的初级视觉皮层（primary visual cortex，又称V1）神经元对比度反应之间的差异，以及V1和内侧颞叶（medial temporal cortex，MT）视觉区神经元反应潜伏期及其变异性之间的差异。结果显示，与年轻猴相比，老年猴V1区神经元对比度敏感性降低，同时伴随着神经元活动信噪比下降；老年猴V1区和MT区神经元反应潜伏期及其变异性显著增加。然而，两个年龄组MT区神经元平均潜伏期之间差异小于V1区神经元平均潜伏期之间的差异，说明MT区神经元能够自我调整老化带来的影响。另外，两个年龄组V1区神经元潜伏期和变异性都具有正相关关系，但是MT区神经元则没有这种相关性。这些结果表明，在老化过程中皮层神经元的对比度和潜伏期反应特性发生了改变。我们推测这种改变可能与视觉皮层内抑制系统功能的降低有关，但是具体的分子机制和神经环路还不清楚。总之，本实验的研究结果为更好的理解老年人在视觉信息处理中时间和空间对比度敏感性及处理速度下降提供了新线索。2.极低频磁场对脑功能的影响及眶额叶认知功能的研究: 实验目的：（1）研究极低频磁场(20 Hz, 14 mT)照射对长期吗啡处理引起的大鼠背侧海马神经元多巴胺D2密度降低的影响；（2）小鼠青春期长期极低频磁场(50 Hz, 2 mT)照射对空间学习记忆的影响；（3）初步探讨了眶额叶在大鼠新异性探索行为中的作用。实验1，我们用免疫组化的方法检测了大鼠背侧海马神经元多巴胺D2受体密度的变化。结果显示，在长期吗啡处理后戒断早期背侧海马神经元多巴胺D2受体密度相对于对照组减少，磁场和吗啡共同作用会强化这种适应，但是这种变化很快恢复正常。这些结果表明长期吗啡处理会引起海马多巴胺系统产生适应；磁场强化了长期吗啡处理对背侧海马多巴胺系统的影响,这为我们先前发现磁场照射延缓了大鼠条件位置偏好消退的研究结果提供了一个内在神经基础。实验2，我们分别用Y-迷宫（two-trial Y-maze）和Morris水迷宫两种行为装置研究了青春期早期磁场暴露对小鼠短时空间识别记忆和长时空间参考记忆的影响。结果显示，磁场暴露并没有影响小鼠Y-迷宫作业，但是提高了水迷宫任务的学习以及记忆保持。这些结果表明磁场对空间记忆的影响是任务依赖性的。实验3，我们用旷场和Y-迷宫两种行为装置研究了眶额叶电损伤对大鼠新异性探索行为的影响。结果显示，眶额叶受损并没有影响大鼠的神经运动能力，但是降低了大鼠在旷场中的行走距离和直立次数以及降低了在Y-迷宫新异臂中的探索时间和穿梭次数。这些结果表明，眶额叶的完整性对大鼠探索新异环境行为是必要的，这可能与眶额叶参与记忆或行为决策功能有关。

Syndiotactically enriched 1,2-selective polymerization of 1,3-butadiene initiated by iron catalysts based on a new class of donors

A series of phosphoryl (P=O) contained compounds: triethylphosphate (a), diethyl phenyl phosphate (b), ethyldiphenylphosphate (c) triarylphosphates (d and h-m), triphenylphosphine oxide (e), phenyl diphenylphosphinate (f) and diphenyl phenylphosphonate (g) have been prepared. Iron catalysts, which are generated in situ by mixing the compounds with Fe(2-EHA)(3) and (AlBu3)-Bu-i in hexane, are tested for butadiene polymerization at 50 degrees C. Phosphates donated catalysts have been, unprecedently, found to conduct extremely high syndiotactically (pentad, rrrr=46.1-94.5%) enriched 1,2-selective (1,2-structure content=56.2-94.3%) polymerization of butadiene.

低熔点间同1,2-聚丁二烯热塑性弹性体的研究

本论文对异辛酸铁(Fe)-亚磷酸二乙酯(P)-三异丁基铝/三乙基铝(Al)催化体系进行研究, 合成熔点低于130℃的间同1,2-聚丁二烯热塑性弹性体,并且发现三异丁基铝与三乙基铝比例对聚合活性有较大的影响。放大实验合成的间同1,2-聚丁二烯熔点为126℃ ,其1,2-结构含量为84%,间同度为81%；数均分子量13万,重均分子量40万,分子量分布为3.0；300%定伸应力为14.2MPa,拉伸强度20.5MPa,扯断伸长率420%,断裂强度20.4MPa,硬度为94邵尔A,热分解温度435℃,具有良好的力学性能和热稳定性。

Why [6,6]- and 1,2-Benzal-3-N-4-O-Cyclic Phenylimidate C-60 Undergo Electrochemically Induced Retro-Addition Reactions while 1,4-Dibenzyl-2,3-Cyclic Phenylimidate C-60 Does Not? C-H center dot center dot center dot X (X = N, O) Intramolecular Interactions in Organofullerenes

The electrochemical properties of a series of structurally related fullerooxazoles, [6,6] cyclic phenylimidate C-60 (1), 1,2-benzal-3-N-4-O-cyclic phenylimidate C-60 (2), and 1,4-dibenzyl-2,3-cyclic phenylimidate C-60 (3), are described, and the spectroscopic characterizations of their anionic species are reported. The results show that compounds I and 2 undergo retro-cycloaddition reactions that lead to the formation of C-60 and C61HPh, respectively, upon two-electron-transfer reduction. However, compound 3 demonstrates much more electrochemical stability as no retro-cycloaddition reaction occurs under similar conditions. Natural bond orbital (NBO) calculations on charge distribution show there is no significant difference among the dianions of 1, 2, and 3, indicating that the electrochemical stability of 3 is unlikely to be caused by the charge distribution difference of the dianions of three compounds. Examination on the crystal structure of compound 3 reveals close contacts of the C-H group with the heteroatoms (N and O) of cyclic phenylimidate, suggesting the existence of C-H center dot center dot center dot X (X = N, O) intramolecular hydrogen bonding among the addends, which is further confirmed by NBO analysis.

PP／间同1,2-聚丁二烯的物理力学性能

添加不同质量分数的间同1,2-聚丁二烯(sPB)热塑性弹性体对聚丙烯(PP)共混改性,研究了共混体系的物理力学性能。PP与sPB结构相似,有良好的相容性,随着w(sPB)从0增至40%,共混体系的屈服拉伸强度、弯曲模量及耐热性有所降低;悬臂梁冲击强度增加,且常温悬臂梁冲击强度增幅较大,但低温悬臂梁冲击强度增加较少;断裂伸长率和熔体流动速率先增加后减少。

Facilitated ion-transfer of sodium cation by (anthraquinone-1-yloxy) methane-15-crown-5 across the water/1,2-dichloroethane microinterface

The transfer of sodium cation facilitated by (anthraquinone-1-yloxy) methane-15-crown-5(L) has been investigated at the water/1,2-dichloroethane microinterface supported at the tip of a micropipette. The diffusion coefficient of (anthraquinone-1-yloxy) methane-15-crown-5 obtained was (3.42 +/- 0.20) x 10(-6) cm(2) s(-1). The steady-state voltammograms were observed for forward and backward scans due to sodium ion transfer facilitated by L with 1:1 stoichiometry. The mechanism corresponded to an interfacial complexation (TIC) and interfacial dissociation (TID) process. The association constant was calculated to be log beta(o) = 11.08 +/- 0.03 in the DCE phase. The association constant of other alkali metals (Li+, K+, Rb+) were also obtained.

Crystal structures of EtEDTB center dot 1.4C(2)H(5)OH center dot 5H(2)O and H4EtEDTB(ClO4)(4)center dot C2H5OH (EtEDTB=N, N, N ', N '-tetrakis[2-(1-ethylbenzimidazolyl)methyl]-1,2-ethanediamine)

The crystal structures of EtEDTB.1.4C(2)H(5)OH.5H(2)O 1 and H4EtEDTB(ClO4)(4).C2H5OH 2 (EtEDTB = N, N,N',N'-tetrakis[2-(1-ethylbenzimidazolyl)methyl]-1,2-ethanediamine) have been determined by single-crystal X-ray diffraction method. Compound 1 crystallizes in the space group P(1) over bar with a = 11.489(2), b = 11.866(3), c = 12.002(3) Angstrom, alpha = 97.47(2), beta = 114.564(13), gamma = 114.11(2)degrees, V = 1266.6(5) Angstrom(3), Z = 1, M-r = 847.48, D-c = 1.111 g/cm(3), F(000) = 456 and mu(MoKalpha) = 0.076 mm(-1). A total of 5207 reflections were measured for 1, of which 4323 were independent. The structure of 1 was solved by direct methods and refined by full-matrix least-squares technique to the final R = 0.0706 and wR = 0.1802 for 1318 observed reflections with I > 2sigma(I). In the structure of 1, centrosymmetric EtEDTB molecules are linked by hydrogen bonds through water and ethanol to form 2-dimensional network. Compound 2 crystallizes in the space group C2/c with a = 24.260(5), b = 13.040(3), c = 17.680(4) Angstrom, beta = 97.50(3)degrees, V = 5545.2(2) Angstrom(3), Z = 4, M-r = 1140.80, D-c = 1.366 g/cm(3), F(000) = 2384 and mu(MoKalpha) = 0.289 mm(-1).