Photoelectrochemical Studies on High Specific Capacitance-Photoactive Interfaces Based on Poly 3,4- Ethylenedioxythiophene/Metal Oxides Assemblies

Inorganic/organic interfaces (IOI) consist of TiO2/PEDOT (poly 3,4-ethylenedioxythiophene) and [PMo12O40]3- or MoO3/PEDOT were subject to photoelectrochemical studies in both aqueous nanosuspensions and in thin solid films. The effects PEDOT modifier caused on the photoelectrochemical behavior of the IOI were investigated using [Fe(CN)6]4- as the photoactive hydrated electron donor agent. Results show that native PEDOT or PEDOT doped with MoO3 thin films increased charge storage capability evident by the high capacitive current. In the case of nano suspensions composed of TiO2/PEDOT the adsorption process of [Fe(CN)6]3- (photolysis product) control of the photoactivity outcome of the IOI assemblies. TiO2/PEDOT shows a lower heterogeneous photochemical response than native TiO2 in short term photolysis times. At longer photolysis times the IOI shows photoactivity greater than that of native TiO2. The interface activities were explained by analyzing the IOI junction characteristics, such as electron affinity, work function and hole/electrons barrier heights. The aqueous nano-systems retained moderate stability as indicated by the reproducibility of their photocatalytic activities. Both [Fe(CN)6]4-and PEDT contributed to the stability of native TiO2 surfaces.

代谢酶NAT2多态性与大肠息肉及腺瘤的复发

目的 研究代谢酶基因NAT2多态性与大肠息肉及腺瘤复发的关系 ,探讨其与大肠癌遗传易感性。方法 在 1980年 ,建立了 40 76例大肠癌高危人群队列 ,这 40 76例均有大肠腺瘤或息肉史。从高危人群中随机抽取 5 2例息肉、腺瘤复发 2次以上者为复发组 ,另抽取 5 2例无复发者为对照 ,从抗凝外周血白细胞中提取DNA ,采用聚合酶链反应 限制性内切酶片段长度多态性 (PCR RFLP)方法分析 ,比较NAT2的多态性分布差异。结果 NAT2野生型Wt/Wt频率在无复发组 (17/ 5 2 ,32 7% )明显高于复发组 (8/ 5 2 ,15 .4% ) ,杂合型在复发组频率为 40 / 5 2 (76 .9% ) ,与无复发组频率30 / 5 2 (5 7.7% )比较 ,差异均有显著意义 (P <0 .0 5 )。以Wt/Wt基因型的危险度 (OR)为 1,则Wt/M 基因型的OR为 2 .96 ,95 %CI为 1.0 91～ 8.0 0 9,M /M 基因型的OR为 2 .12 5 ,95 %CI为 0 .6 6 6～6 781。在复发与无复发组中 ,未发现NAT2快速与慢速酶的差异。结论 NAT2野生型 (Wt/Wt)可能是大肠腺瘤复发的保护因素 。