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41.
脑细胞激活素药物的化学成分分析 总被引:1,自引:0,他引:1
采用日本岛津LC-60A型高压液相色谱仪和美国P-E3030型原子吸收分光光度计,对该药进行了氨基酸、维生素和化学元素的含量测定。结果表明,该药含有18种氨基酸,不少于3种维生素和20几种化学元素,为进一步改进该药物的合理配制方法和临床应用提供了参考数据。 相似文献
42.
Michael Grätzel 《Journal of Sol-Gel Science and Technology》1994,2(1-3):673-677
Transparent nanocrystalline films of oxide semiconductors such as TiO2 and Fe2O3 have been prepared on a conducting glass support employing a sol-gel procedure. The films are composed of nanometer-sized particles sintered together to allow for percolative charge carrier transport. The internal surface of these films is very high, roughness factors of the order of 1000 being readily obtained. Electric polarization was applied for forward and reverse biasing of the films and the resulting optical changes have been analyzed to derive their flat band potential. Band gap excitation of such nanocrystalline semiconductors produces electron-hole pairs which migrate through the film to be collected as electric current. Steady state photolysis and time resolved laser techniques have been applied to scrutinize the mechanism of light induced charge separation within the nanostructure. When derivatized with a suitable chromophore, TiO2 films give extraordinary efficiencies for the conversion of incident photons into electric current, exceeding 90% for certain transition metal complexes within the wavelength range of their absorption band. The underlying physical principles of these astonishing findings will be discussed. Exploiting this discovery, we have developed a new type of photovoltaic device whose overall light to electric energy conversion yield is 10% under simulated AM 1.5 solar radiation. 相似文献
43.
Ginette Ratovo Jean‐Pierre Souchard Pascale Urizzi Yvon Coulais Franoise Nepveu Etienne Hollande 《应用有机金属化学》2004,18(1):1-8
Pancreatic cancer has an extremely poor prognosis, due, in part, to lack of methods for early diagnosis. The present study was designed to evaluate the potential of labeling low‐density lipoprotein (LDL) with a radionuclide using a lipid chelating agent, bis(stearylamide) of diethylenetriaminepentaacetic acid (L), to detect pancreatic tumors by gamma‐scintigraphy. Previous studies indicated that the difficulty of visualization of pancreatic tumors was due to their poor vascularization. This study compares the ability of two radiotracers, 111In–L–LDL and 153Gd–L–LDL to target highly vascularized rat pancreatic tumors (AR4‐2J) implanted in nude mice. Biodistribution studies showed that the tumor uptake of 111In–L–LDL and 153Gd–L–LDL tracers was twofold and fivefold higher respectively than with the controls (111In citrate and 153Gd citrate respectively). These tracers would thus be suitable for scintigraphic imaging. We show here that LDL could be employed as a delivery system for tracers such as 111In or 153Gd when these two radionuclides are complexed by a lipid‐chelating anchor, and that 111In–L–LDL and 153Gd–L–LDL enabled better visualization of the pancreatic tumor tissues, with a better result with 153Gd–L–LDL. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
44.
程治国 《宁波大学学报(理工版)》2004,17(1):28-31
提出了在无外力作功的情况下,具有Bauschinger效应的弹塑性材料处于屈服状态产生自发的塑性流动时应满足的条件.这个条件不仅与材料的力学性能有关,而且还处决于材料的具体的载荷边界条件和变形.举例说明了承受拉一扭组合的薄壁圆筒中,采用组合强化模型时,产生塑性流动的具体条件. 相似文献
45.
从4~10周龄药物流产胚胎的生殖嵴和肠系膜组织中分离原始生殖细胞(primordial germ cells,PGCs),培养在添加人重组白血病抑制因子(rh LIF)、人重组碱性成纤维细胞生长因子(rh bFGF)和Forskolin的小鼠饲养层细胞上.经过4~7 d培养,PGCs形成典型的鸟巢状集落.集落在传代过程中保持碱性磷酸酶活性,且胚胎阶段性特异抗原1(SSEA-1)、胚胎阶段性特异抗原3(SSEA-3)免疫荧光染色呈阳性.具有分化潜能的PGCs能在体外连续传代培养12代.结果表明从药物流产胚胎中分离的人类PGCs可以在体外培养成为具有分化潜能的多能性干细胞. 相似文献
46.
采用MTT比色法对体外培养的肿瘤细胞进行细胞毒作用实验,验证槲寄生蛋白注射液体外抗肿瘤效果.并且鉴定这种检测方法的有效性。实验结果表明槲寄生蛋白注射液有一定的体外抗肿瘤效果;MTT比色法是一种可用的体外细胞毒作用检测法,为新药品的开发提供了实验依据。 相似文献
47.
In this article a new technique was developed to fabricate scaffolds with a unique microstructure by solid–liquid separation in combination with particulate-leaching. Firstly, the effects of polymer concentration, quenching temperature on the porous morphology and the mechanical property of obtained scaffolds during solid–liquid separation have been investigated. Then, salt granules as porogen were introduced into the solid–liquid phase separation to produce the unique pore structure of the scaffold. The pore diameter of the scaffold could be controlled with the particulate size and the wall of pores possessed special microstructure, which enhanced the pore interconnectivity. The cell culture results confirmed that a good interconnectivity of the scaffold prepared by the improved solid–liquid separation was useful for nutrition transportation and cell proliferation. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
48.
Total syntheses of the peptide enamide natural products terpeptin and aspergillamides A and B are reported. An oxidative decarboxylation-elimination protocol is employed to construct the indolic enamide moiety. Unambiguous stereochemical assignment of (−)-terpeptin is accomplished by synthesis of all possible stereochemical analogues. Select compounds have been evaluated in cell cycle inhibitor assays which show that the natural amino acid configuration of terpeptin has the most potent inhibitory activity. 相似文献
49.
Finite element analysis of fluid flow with moving free surface has been performed in 2‐D and 3‐D. The new VOF‐based numerical algorithm that has been proposed by the present authors (Int. J. Numer. Meth. Fluids, submitted) was applied to several 2‐D and 3‐D free surface flow problems. The proposed free surface tracking scheme is based on two numerical tools; the orientation vector to represent the free surface orientation in each cell and the baby‐cell to determine the fluid volume flux at each cell boundary. The proposed numerical algorithm has been applied to 2‐D and 3‐D cavity filling and sloshing problems in order to demonstrate the versatility and effectiveness of the scheme. The proposed numerical algorithm resolved successfully the free surfaces interacting with each other. The simulated results demonstrated applicability of the proposed numerical algorithm to the practical problems of large free surface motion. It has been also demonstrated that the proposed free surface tracking scheme can be easily implemented in any irregular non‐uniform grid systems and can be extended to 3‐D free surface flow problems without additional efforts. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
50.
In this paper we describe the experimental analysis of a novel ion-exchange polymer metal composite (IPMC) actuator under
large external voltage. The experimental analysis is supplemented with a coupled thermodynamic model, which includes mass
transport across the thickness of the polymer actuator, chemical reactions at boundaries, and deformation as a function of
the solvent (water) distribution. In this paper, the case of large electrode potentials (over 1.2 V) has been analyzed experimentally
and theoretically. At these voltage levels, electrochemical reactions take place at both electrodes. These are used in the
framework of overpotential theory to develop boundary conditions for the water transport in the bulk of polymer. The model
is then simplified to a three-component system comprised of a fixed negatively charged polymeric matrix, protons, and free
water molecules within the polymer matrix. Among these species, water molecules are considered to be the dominant species
responsible for the deformation of the IPMC actuators. Experiments conducted at different initial water contents are described
and discussed in the context of the proposed deformation mechanism. Comparison of numerical simulations with experimental
data shows good agreement. 相似文献