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81.
UV-B induced keratinocyte apoptosis is blocked by 2-selenium-bridged beta-cyclodextrin,a GPX mimic 总被引:1,自引:0,他引:1
Mu Y Lv S Ren X Jin G Liu J Yan G Li W Shen J Luo G 《Journal of photochemistry and photobiology. B, Biology》2003,69(1):7-12
Cell proliferation and cell death of keratinocytes are tightly regulated to ensure epidermal homeostasis. UV-B induces keratinocyte apoptosis. UV-B also induces lipid peroxidation of keratinocytes to increase their amount of malondialdehyde (MDA). These phenomena can be explained by the production of reactive oxygen species (ROS) induced by UV-B radiation. We synthesized 2-selenium-bridged beta-cyclodextrin (2-SeCD) to imitate glutathione peroxidase (GPX), an important antioxidant and established a damage system, in which keratinocytes can be damaged by Ultraviolet B (UV-B) radiation. Using this damage system we studied 2-SeCD protection of keratinocytes against injury induced by UV-B. Experimental results showed that 2-SeCD could protect keratinocytes from apoptosis. Moreover, 2-SeCD inhibits lipid peroxidation of keratinocytes and scavenges ROS. 2-SeCD inhibits the UV-B induced apoptotic signal transduction. This antiapoptotic mechanism may be partly related to the elimination of hydrogen peroxide. 相似文献
82.
当前光学塑料的研究方向及综合性能的均衡 总被引:1,自引:0,他引:1
根据结构与性能的关系对当前光学塑料的主要研究方向进行了归纳和总结,介绍了具有高折光指数、高耐热性及其它功能性的新型光学材料,指出了性能之间均衡对实现化的意义。 相似文献
83.
He F Cheng G Zhang H Zheng Y Xie Z Yang B Ma Y Liu S Shen J 《Chemical communications (Cambridge, England)》2003,(17):2206-2207
Building a new structual oligo(phenylenevinylene) by linking trimeric phenylenvinylene (TPV) through the phenylphenyl bond of a central phenylene ring was reported. The resultant TPV dimers exhibit weak intermolecular interactions and intense blue photoluminescence in the solid state as well as high phase transition temperatures up to 250 degrees C. Organic light-emitting devices (OLEDs) based on these materials display blue emission with low turn-on voltage (about 3 V), maximum luminance approaching 2000 cd m(-2) and efficiency up to 1.6 cd A(-1). 相似文献
84.
全倒易空间X-射线散射理论分析(FRS—XRSA)是研究与表征择优取向高聚物结晶度与取向分布的一种新方案,它可以解决粉沫法测定结晶度时取向试样难以消取向的困难,测定拉伸和回复过程中正在形变的取向试样的结晶度.在以前的工作中,对双轴取向的薄膜,仅进行了幅度β=0°(MD)与90°(TD)两个轴向,△α=10°的XRS测定,这样推得的结晶度事实上是MT双轴XRS的结晶度,即MT-XRS结晶度X,这种处理包含着XRS沿MT方向作均匀分布的近似.本文为了澄清这一问题,作了下述三点改进:第一,利用FRS中XRS的强度分布,内插计算αi;,βi=0°~90°,△βi=10°的XRS,由此求得较符合理论要求的FRS-XRS结晶度X;第二,进行了FRS-XRS的极角因子cosαi;校正;第三,合理地处理了当极角αi=90°时出现奇点的困难.结果较合理.同时亦获得了晶粒度在FRS中的分布情况. 相似文献
85.
模拟谷胱甘肽过氧化物酶活性三肽的合成及表征 总被引:1,自引:0,他引:1
用B,B-二氟硼杂唑烷酮保护谷氨酸的α-氨基和α-羧基,通过液相合成法制得谷氨酰-γ-丝氨酰-甘氨酸三肽。结合苯甲基磺酰氟(PMSF)与硒化氢(H2Se)的突变,再经纯化制得具有谷胱甘肽过氧化物酶活性的三肽模拟物,即γ-谷氨酰-硒代半腕氨酰-甘氨酸。元素分析、氨基酸分析均证明了两种三肽的结构。电子能谱技术分析测得硒的价态及含量。 相似文献
86.
Colloidal Au/Ag multilayer films were prepared by alternate assembly of Au nanoparticles with a size of 5 +/- 1.2 nm and Ag nanoparticles with a size of 10 +/- 2.4 nm by using 1,5-pentanedithiol as cross-linker. Nanoporous gold films with a ligament size of 26.7 +/- 4.6 nm were then prepared by selective dissolution of sacrificial templates of silver particles in colloidal Au/Ag multilayers. The complete dissolution of Ag particles in colloidal Au/Ag multilayers in a mixture solution of 3.0 mM HAuCl(4) and 3 M NaCl took place at room temperature without damage of the colloidal Au film. This method to prepare nanoporous gold films was further extended to the preparation of nanoporous gold nanotubes by depositing colloidal Au/Ag film on the inner wall of anodic aluminum oxides (AAO) followed by dissolution of colloidal Ag and removal of AAO templates. 相似文献
87.
88.
Patterned poly(acrylic acid) (PAA)/poly(allylamine hydrochloride) (PAH) multilayer films with line structures of different lateral size and vertical height were fabricated by a room-temperature imprinting technique, and their cell adhesion properties were investigated. The nonimprinted PAA/PAH multilayer films are cytophilic toward NIH/3T3 fibroblasts and HeLa cells whether PAA or PAH is the outer most layer. In contrast, the PAA/PAH multilayer films with a 6.5-microm-line/3.5-microm-space pattern structure are cytophobic toward NIH/3T3 fibroblasts and HeLa cells when the height of the lines is 1.29 microm. By either increasing the lateral size of the patters to 69-microm-line/43-mum-space or decreasing the height of the imprinted lines to approximately 107 nm, imprinted PAA/PAH multilayer films become cytophilic. This kind of transition of cell adhesion behavior derives from the change of the physical pattern size of the PAA/PAH multilayer films and is independent of the chemical composition of the films. The easy patterning of layer-by-layer assembled polymeric multilayer films with the room-temperature imprinting technique provides a facile way to tailor the cellular behavior of the layered polymeric films by simply changing the pattern dimensions. 相似文献
89.
Wang Q Yu D Wang Y Sun J Shen J 《Langmuir : the ACS journal of surfaces and colloids》2008,24(20):11684-11690
Water-soluble tris(2,2'-bipyridine)ruthenium(II) complex (Rubpy) and water-insoluble tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) complex (Rudpp) were successfully incorporated into zirconium phosphate (ZrPS) films fabricated by a facile layer-by-layer (LbL) adsorption and reaction method. Rubpy-incorporated ZrPS films were fabricated by the LbL adsorption and reaction method employing a mixture solution of Rubpy and phosphate salt. Rubpy was incorporated into ZrPS films during the formation of ZrPS layers because of the electrostatic interaction between them. Rudpp was dissolved in the mixture solution of aqueous phosphate salt and ethanol and was incorporated into ZrPS films through the formation of ethanol preintercalated ZrPS layers. The successful incorporation of Rubpy and Rudpp into ZrPS films was confirmed by UV-vis absorption spectroscopy. Rubpy and Rudpp have concentrations of 0.915 x 10 (14) and 3.23 x 10 (14) molecules/cm (2) in each ZrPS layer, respectively. Scanning electron microscopy measurements indicate that the as-prepared Rubpy-incorporated ZrPS films are smooth while the as-prepared Rudpp-incorporated ZrPS films are porous. The porous Rudpp-incorporated ZrPS films are suitable to use as oxygen sensors because the luminescence of Rudpp incorporated into the ZrPS films can be quenched by oxygen and the porous film structure facilitates the permeation of oxygen into and out of the film. 相似文献
90.
Mechanically stable antireflection and antifogging coatings fabricated by the layer-by-layer deposition process and postcalcination 总被引:1,自引:0,他引:1
Zhang L Li Y Sun J Shen J 《Langmuir : the ACS journal of surfaces and colloids》2008,24(19):10851-10857
Complexes of poly(diallyldimethylammonium chloride) (PDDA) and sodium silicate (PDDA-silicate) are alternately deposited with poly(acrylic acid) (PAA) to fabricate PAA/PDDA-silicate multilayer films. The removal of the organic components in the PAA/PDDA-silicate mulilayer films through calcination produces highly porous silica coatings with excellent mechanical stability and good adhesion to substrates. Quartz substrates covered with such porous silica coatings exhibit both antireflection and antifogging properties because of the reduced refractive index and superhydrophilicity of the resultant films. A maximum transmittance of 99.86% in the visible spectral range is achieved for the calcinated PAA/PDDA-silicate films deposited on quartz substrates. The wavelengths of maximum transmittance could be well tailored by simply changing the deposition cycles of multilayer films. The usage of PDDA-silicate complexes allows for the introduction of high porosity to the resultant silica coatings, which favors the fabrication of antireflection and antifogging coatings with enhanced performance. Meanwhile, PDDA-silicate complexes enable rapid fabrication of thick porous silica coatings after calcination because of the large dimensions of the complexes in solution. The easy availability of the materials and simplicity of this method for film fabrication might make the mechanically stable multifunctional antireflection and antifogging coatings potentially useful in a variety of applications. 相似文献