The influence of polyelectrolyte charges of polyurethane membrane surface on the growth of human endothelial cells

A novel technique to introduce free amino groups onto polyester scaffolds via aminolyzing the ester groups with diamine has been developed recently. The introduction of the free amino groups on these polyester surfaces provides us the possibility to modify polymer surface in a simpler manner, e.g. layer-by-layer assembly of charged species. By this technique, many negatively and positively charged biopolymers were deposited alternatively on polyurethane surface. The deposition process was monitored by fluorescence spectroscopy and advancing contact angle measurements. The result of human endothelial cells cultured in vitro showed that cells on negatively charged surface could not spread and flatten well due to the electrostatic repulsion. The lower attachment ratio induced the lower proliferation ratio. However, after the surface charge was inversed by collagen, both attachment and proliferation ratios increased to different extent. Observed under SEM, cells also presented a flat and spreading morphology.     

Reaction mechanism studies on isoquinoline with hydroxyl radical in aqueous solutions

The reaction mechanism between isoquinoline and ·OH radical in aqueous dilute solutions under different conditions was studied by pulse radiolysis. The main characteristic peaks in these transient absorption spectra were attributed and the growth-decay trends of several transient species were investigated. Under neutral or alkaline conditions, the reaction of ·OH radical and isoquinoline produces OH-adducts with respective rate constants of 3.4 × 10⁹ and 6.6 × 10⁹ mol⁻¹ · dm³ · s⁻¹ while under acidic conditions, the isoquinoline was firstly protonated and then ·OH added to the benzene ring and produced protonated isoquinoline OH-adducts with a rate constant of 3.9 × 10⁹ mol⁻¹ · dm³ · s⁻¹. With a better understanding on radiolysis of isoquinoline, this study is of help for its degradation and for environmental protection. __________ Translated from Journal of Fudan University (Natural Science), 2006, 45(6): 774–778 [8BD1;81EA: 590D;65E6;5B66;62A5;(自然科学版)]     

Novel Pb(II), Zn(II), and Cd(II) coordination polymers constructed from ferrocenyl-substituted carboxylate and bipyridine-based ligands

Treatment of two kinds of ferrocenyl-substituted carboxylate ligands (3-ferrocenyl-2-crotonic acid, HOOC-CH=(CH(3))CFc (Fc=(eta(5)-C(5)H(5))Fe(eta(5)-C(5)H(4))) or O-ferrocecarbonyl benzoic acid, o-HOOCC(6)H(4)COFc with Pb(OAc)(2).3H(2)O, Zn(OAc)(2).2H(2)O, or Cd(OAc)(2).2H(2)O) resulted in four novel ferrocene-containing coordination polymers [[Pb(mu(2)-eta(2)-OOCCH=(CH(3))CFc)(2)].MeOH](n) (1), [[Zn(o-OOCC(6)H(4)COFc)(2)(4,4'-bipy)(H(2)O)(2)].2MeOH.2H(2)O](n) (4,4'-bipy = 4,4'-bipyridine) (2), [[Cd(o-OOCC(6)H(4)COFc)(2)(bpe)(MeOH)(2)].2H(2)O](n) (bpe = 1,2-bis(4-pyridyl)ethene) (3), and [Pb(o-OOCC(6)H(4)COFc)(eta(2)-o-OOCC(6)H(4)COFc)(bpe)](n)() (4). Their crystal structures have been characterized by single X-ray determinations. In polymer 1, Pb(II) ions are bridged by tridentate FcC(CH(3))=CHCOO(-) anions, forming an infinite chain [Pb(mu(2)-eta(2)-OOC=CH(CH(3))CFc)(2)](n). In polymers 2-4, there are three kinds of components, metal ions, o-FcCOC(6)H(4)COO(-) units, and organic bridging ligands. The bipyridine-based ligands connect metal ions leading to a one-dimensional chain with o-FcCOC(6)H(4)COO(-) units acting as monodentate or chelate ligands in the side chain. Such coordination polymers containing ferrocenyl-substituted carboxylate and bipyridine-based ligands are very rare. The solution-state differential pulse voltammetries of polymers 1-4 were determined. The results indicate that the half-wave potential of the ferrocenyl moieties is influenced by the Pb(II) ions in polymer 1 and strongly influenced by Zn(II), Cd(II), or Pb(II) ions in polymers 2-4. The thermal properties of the four polymers were also investigated.     

PREPARATION OF PERFLUOROOCTANOYL-MODIFIED POLY(VINYL-ALCOHOL)S AND THEIR ADSORPTION AT AN AIR-WATER INTERFACE

Perfluorooctanoyl modified poly(vinyl alcohol)s (FPVA) were prepared by means of substituting a small amountof hydroxyl groups on the backbone of poly(vinyl alcohol), for which the initial degree of polymerization is equal to 1750.The substitution extent, defined by the number of substituting units in a chain, for the four FPVA samples was in the range of0.5-5 perfluorooctanoyl groups per chain. The FPVA samples with the highest substitution extent still had good solubility inwater. It was shown by experimental measurement at 30.0±0.1℃ that the surface tension of the aqueous solution of thehighest substituted FPVA decreased to 16.6 mN/In at a higher concentration, e.g about 0.1 g/mL. Obviously,macromolecules of FPVA exhibit a very strong tendency to adsorb at the air-water interface, because the hydrophobicperfluorooctanoyl groups in FPVA have a very high surface activity as they are in small molecular fluorinated surfactants.The chain conformation of such a model polymer adsorbed on the air-water interface was also discussed.     

Kinetics and mechanism of the reaction of a quasi-aromatic copper(II) complex, [Cu(PnAO)-6H]0, with formaldehyde

The kinetics of the reaction of CH₂O with a quasi-aromatic metal complex (1,1,2,8,9,9-hexamethyl-4,6-dioxa-5-hydro-3,7,10,14-tetraazacyclotetradecane-2,7,10,12-tetraene)copper(II), [Cu(PnAO)-6H]⁰ (AH), have been studied spectrophotometrically under neutral conditions in 1/3(v/v) MeOH–H₂O. The Cu, 2N, 3C quasi-aromatic heterocyclic ring in AH is highly reactive towards CH₂O at the central-aromatic-carbon atom, C(12) and the following reaction mechanism is proposed. The compounds AH, A—CH₂OH and A—CH₂—A were isolated and identified by i.r spectroscopy and by elemental analysis. The kinetic data supported the proposed reaction sequence. All reactions were second order overall. The rate constants and corresponding activation parameters for every step were obtained and are discussed.     

O(3P)原子和硅烷化学反应动力学研究

本文报道了用流动放电-化学发光技术测定O(~3P)和硅烷化学反应速率常数.在293—413K范围内, 结果为k=(1.05±0.36)×10~(-10)exp[(-3.06±0.10) kcal·mol~(-1) /RT] cm~3·molecule~(-1)·s~(-1)并用过渡态理论将上述实验结果外推到200—2000 K范围内. 计算结果以三参数公式表示为: k=7.67×10~(-19) T~(2.59) exp(-720 cal·mol~(-1)/RT) cm~3·molecule~(-1)·s~(-1).     

配合物的生成热与配体的质子化热之间的直线焓关系——Ⅶ. 镍(Ⅱ)-2,2′联吡啶-N,N′-双(对位取代苯基)乙二胺的二元及三元体系

使用MS 80型Calvet微量热计, 在25 ℃, 0.1mol·dm~(-3)(NaClO_4)的50%(V/V)二氧六环溶液中, 测定了镍(Ⅱ)-N,N′-双(对位取代苯基)乙二胺二元及镍(Ⅱ)-2,2′-联吡啶-N,N′-双(对位取代苯基)乙二胺三元体系的生成热和N,N′-双(对位取代苯基)乙二胺的质子化热, 发现在二元和三元配合物的生成热、生成熵与配体的质子化热及质子化熵之间存在较好的线性关系。     

芳基三氮烯4-位取代基对抗癌活性影响的构象分析

传统的药物设计和新药开发主要是依靠随机筛选,这种方法误差大,且需要费大量时间和经费,其结果也经常不能达到预期的设想。即使是一个国际性的大制药集团,每年平均要合成上万个化合物才能从中筛选出一个可以成为商品的新药。这种状况迫使我们去寻找一条新的打破常规的途径研究新药。近年来,随着计算机图形系统的广泛应用,对药物构效关系的研究得到了卓有成效的发展,取得了一些成功的例子。如抗菌抗癌琥珀酰-L脯氨酸就是计算化学与分子图形技术相结合的成果,目前已投放市场。     

瓜环与2,2''''-联吡啶衍生物的相互作用

利用~1H NMR技术、紫外吸收光谱及荧光光谱方法,考察了对六、七以及八元瓜环与多种2,2'-联吡啶衍生物相互作用形成的主客体配合物结构及光学性质.研究结果显示,不同的2,2'-联吡啶衍生物与瓜环作用不仅形成多种不同包结比的稳定包结配合物,且所形成的主客体包结配合物的结构及光谱性质也各不相同;同时用几种方法协同考察起到了互为补充、互为验证的良好效果.