9,10-Dimetallatriptycenes of group 14: a structural study

From ortho-phenylenemagnesium (1), 9-phenyl-9-germa-10-silatriptycene (5) was prepared via a simple one pot procedure. The previously prepared 9-methyl-10-phenyl-9,10-digermatriptycene (4) and 5 are the first germanium-containing 9,10-dimetallatriptycenes to be structurally characterised. The availability of these structural data allows a comparative discussion of 9,10-dimetallatriptycenes of Group 14.

Structure of l-Diphenylmethyl-3-hydroxyazetidinium Chloride,* C 16 H lsN O+.CI -

M r=275.8, monoclinic, P21/a, a= 12.356 (5), b=9.054 (4), c= 14.043 (4) A, t= 100.34 (3) ° , V=1545.5A 3, Z=4, D,,,= 1.14, D x = 1.185 Mg m -3, p(Mo Ka, /l = 0.7107 ]k) = 2.77 mm -1, F(000) = 584.0, T= 293 K, R = 0.053 for 1088 reflections. The four-membered ring is buckled 13.0 ° (0= 167.0°). The azetidinium moiety is linked to the C1- ion through a hydrogen bond [O-H...C1 = 3.166 (5) A].

Bufadienolides. 8. 12(13→14)abeo skeletal rearrangements

Several methods were developed for converting isodigitoxigenin (2a) into methyl acetals 4b and 4c. Of these, methanolysis (followed by acetylation) of isodigitoxigenin in the presence of p-toluenesulfonic acid proved most useful. Each isomer reached an equilibrium corresponding to ca. 3:1 acetal 4c to 4b within 15 min in benzene containing p-toluenesulfonic acid. Addition of dihydropyran to the equilibrium mixture resulted in excellent conversion into vinyl ether 5a. Heating either acetal 4b or 4c in benzene containing p-toluenesulfonic acid led to a skeletal rearrangement culminating in formation of C-norcardenolide 6. In addition to results of physical measurements, the structure of spiran 6 was confirmed by degradation to methyl ketone 8. Similar rearrangement of isodigitoxigenin gave spiran 9 accompanied by C-norcardenolide 6. Treating lactone 9 with p-toluenesulfonic acid in methanol-water provided acetals 10a and 10b, which on further contact with p-toluenesulfonic acid in refluxing benzene gave lactone 9 and cardenolide 6. Evidence underlying the stereochemical assignments noted for structures 4, 9, and 10 was also discussed.

A Pd-8 Tetrafacial Molecular Barrel as Carrier for Water Insoluble Fluorophore

A new carbazole-based tetraimidazole ligand 1,3,6,8-tetra(1H-imidazol-1-yl)-9-methyl-9H-carbazole (L) has been synthesized. The unsymmetrical nature of L as well as the rotational freedom of imidazole donor moieties around C-N bond make it a special building unit, which upon treatment with cis-(tmeda)Pd(NO3)(2) produced an unprecedented single linkage-isomeric Pd-8 tetrafacial molecular nanobarrel (PSMBR-1) tmeda N,N,N',N'-tetramethylethane-1,2-diamine]. Unlike closed architectures, open barrel architecture of water-soluble PSMBR-1 makes it an ideal host for some water insoluble polyaromatic hydrocarbons in aqueous medium; one such inclusion complex coroneneCPSMBR-1 was characterized by X-ray diffraction study. Moreover, the potential application of PSMER-1 as carrier in aqueous medium for the transportation of water insoluble fluorophore (perylene) for live cell imaging is explored.

蛋白激酶C在HIV复制中的作用与药物发现

蛋白激酶C ( PKC)是一类磷脂依赖的丝氨酸/苏氨酸 蛋白激酶, PKC在中枢神经系统疾病及心血管紊乱等多种人 类疾病中都发挥了重要作用。研究发现, PKC可以通过多种 途径刺激H IV病毒的活化,并磷酸化病毒复制周期中的多 种蛋白,如P17gag、Nef、Rev和Vif等,这些蛋白的磷酸化在 病毒复制周期中起到了不可忽视的作用。了解PKC与H IV 及细胞间的复杂关系,开发抑制PKC蛋白激酶的药物从而 达到抑制H IV复制的目的,或激活PKC从而减少或消除体 内潜伏的H IV病毒库是对PKC在抗H IV研究中应用提出的 两个主要方向,对于开发新型抗H IV药物有重要意义。

鲤科鱼类的c-myc CDS及其系统发育关系

鲤科鱼类在东亚的物种多样,分布广泛,物种特征尺寸差异明显,弄清其功能基因的系统演变,对于理解物种分化和功能进化具有重要意义.以具有重要生长调控作用的c-myc基因为标记,通过PCR扩增、克隆和测序,共获得41种鲤科鱼类和外类群c-myc基因全序列,发现并分析了c-myc编码区的两个高变异区.基于c-myc CDS序列,分别采用最大简约法(MP)、最大似然法(ML)和Bayesian法重建了鲤科鱼类的系统发育关系.3种方法所得系统发育关系较为相似.当以亚口鱼科的胭脂鱼(Myxocyprinus asiati

在GaSb衬底上生长c-GaN的初步研究

AES、XPS和XRD谱结果证明

细胞色素c在羟基磷灰石修饰玻碳电极上的直接电化学

采用沉淀法合成羟基磷灰石纳米晶体 ,由于具有独特的多吸附位点特征 ,羟基磷灰石可作为一种新型电子传递促进剂用于细胞色素c的直接电化学研究 .在pH 7.0的磷酸盐缓冲溶液中 ,细胞色素c在羟基磷灰石修饰玻碳电极表面于0 0 74V (vs .Ag/AgCl)处有一对准可逆的氧化还原峰 ,为细胞色素c血红素辅基Fe(Ⅲ ) /Fe(Ⅱ )电对的特征峰 .实验结果表明细胞色素c与羟基磷灰石之间的静电作用 ,促进了细胞色素c在玻碳电极表面扩散控制的准可逆单电子转移过程 .讨论了电位扫描速度、溶液离子强度对细胞色素c直接电化学的影响

气相酯化反应的高效催化剂──活性炭固载的杂多酸（HPA／C）

在气－固反应体系中研究了固载在活性炭上的硅钨（ＳｉＷ_（１２））和磷钨（ＰＷ_（１２））杂多酸在合成乙酸乙酯和乙酸丁酯中的催化性能。实验结果表明，反应温度、空间速度和反应物的配比均对催化活性有明显影响，并且，负载催化剂表面酸量与酯化反应活性之间存在着相应的顺变关系。催化剂在较低反应温度和相当大的流速下具有较高的酯化活性，且性能稳定，有一定的应用前景。

青藏高原东部高寒草甸植物δ~(13)C年间变化及其环境分析

植物有机体稳定碳同位素组成受植物生长期间气候环境因子的影响,包含了大量的环境信息。要真正理解植物体同位素组成所包含的环境信息首先要研究植物体同位素组成与环境之间的关系。文章通过分析2002年和2003年青藏高原东部青海省门源县境内隶属于19科41属51种植物叶片的δ~(13)C值,研究高寒草甸植物稳定碳同位素组成的年间变化及其与环境因子的关系,分析影响δ~(13)C值变化的关键因子。结果表明,所测植物的δ~(13)C值分布在一个很小的范围-29.2‰～-24.9‰之间,平均值为-26.9‰,说明所测植物的光合作用均通过C3途径实现,这可能与该研究区较低温度有关。研究发现一年生植物δ~(13)C值明显低于多年生植物,而且一年生和多年生植物δ~(13)C值之间的差异在2002年（t=-3.031,P〈0.01）和2003年（t=-3.567,P〈0.001）均能达到显著性水平,表明多年生植物水分利用效率显著高于一年生植物,能更好的适应该地区寒冷干燥的低温环境。两年间植物δ~(13)C值有明显不同,2003年显著低于2002年（t=6.786,P〈0.001）。通过分析两年间环境因子的变化认为植物叶片δ~(13)C值的年间变化主要是由于降水的变化引起的,随降雨量的增加而降低。不同植物种δ~(13)C值年间变化差别很大,反应了植物对环境变化的不同响应。在植被恢复中应选用植物δ~(13)C值随环境变化存在较大差异的物种,因为此类物种能够采取不同的对策适应该地区环境的变化。

Supramolecular hydrogen-bond structures and magnetic interactions in basal-apical, dinuclear, azide-bridged copper(II) complexes

The synthesis, characterisation, X-ray single crystal structures and magnetic properties of three new basal-apical mu(2)-1,1-azide-bridged complexes [(CuLN3)-N-1](2) (1), [(CuLN3)-N-2](2) (2) and [(CuLN3)-N-3](2) (3) with very similar tridentate Schiff-base blocking ligands {HL1 = N-[2-(ethylamino) ethyl] salicylaldimine; HL2 = 7-(ethylamino)-4-methyl-5-azahept-3-en-2-one; HL3 = 7-amino-4-methyl-5-azaoct-3-en-2-one} have been reported [complex 1: monoclinic, P2(1)/c, a = 8.390(2), b = 7.512(2), c = 19.822(6) Angstrom, beta = 91.45(5)degrees; complex 2: monoclinic, P2(1)/c, a = 8.070(9), b = 9.787(12), c = 15.743(17) A, beta = 98.467(10)degrees; complex 3: monoclinic, P2(1)/n, a = 5.884(7), b = 16.147(18), c = 11.901(12) Angstrom, beta = 90.050(10)degrees]. The structures consist of neutral dinuclear entities resulting from the pairing of two mononuclear units through end-on azide bridges connecting an equatorial position of one copper centre to an axial position of the other, The copper ions adopt a (4+1) square-based geometry in all the complexes. In complex 2, there is no inter-dimer hydrogen-bonding. However, complexes 1 and 3 form two different supramolecular structures in which the dinuclear entities are linked by H-bonds giving one-dimensional systems. Variable temperature (300-2 K) magnetic-susceptibility measurements and magnetisation measurements at 2 K reveal that all three complexes have antiferromagnetic coupling. Magneto-structural correlations have been made taking into consideration both the azido bridging ligands and the existence of intermolecular hydrogen bonds. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).

Treatment with supplementary arginine, vitamin C and zinc in patients with pressure ulcers: A randomised controlled trial

Background & Aims
Nutrients putatively implicated in pressure ulcer healing were evaluated in a clinical setting.

Methods
Sixteen inpatients with a stage 2, 3 or 4 pressure ulcer randomised to receive daily a standard hospital diet; a standard diet plus two high-protein/energy supplements; or a standard diet plus two high-protein/energy supplements containing additional arginine (9 g), vitamin C (500 mg) and zinc (30 mg). Nutritional status measurements (dietary, anthropometric and biochemical) and pressure ulcer size and severity (by PUSH tool; Pressure Ulcer Scale for Healing; 0=completely healed, 17=greatest severity) were measured weekly for 3 weeks.

Results
Patients’ age and BMI ranges were 37–92 years and 16.4–28.1 kg/m2, respectively. Baseline PUSH scores were similar between groups (8.7±0.5). Only patients receiving additional arginine, vitamin C and zinc demonstrated a clinically significant improvement in pressure ulcer healing (9.4±1.2 vs. 2.6±0.6; baseline and week 3, respectively; P<0.01). All patient groups presented with low serum albumin and zinc and elevated C-reactive protein. There were no significant changes in biochemical markers, oral dietary intake or weight in any group.

Conclusions
In this small set of patients, supplementary arginine, vitamin C and zinc significantly improved the rate of pressure ulcer healing. The results need to be confirmed in a larger study.

Crystal structure of potassium trifluoro[1,3-dithiano]borate, K(C 4S2H7BF3)

C4H7BF3KS2, monoclinic, P121/c1 (no. 14), a = 14.7374(3) Å, b = 9.0612(1) Å, c = 13.5805(2) Å, β = 98.964(4)°, V = 1791.4 Å3, Z = 8, Rgt(F) = 0.029, wRref(F2) = 0.010, T = 296 K. © by Oldenbourg Wissenschaftsverlag.

Evaluation of canonical siRNA and dicer substrate RNA for inhibition of hepatitis C virus genome replication: a comparative study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)