UVA ユウドウ ヒフ ヒカリロウカ ニオケル シシツ カサンカブツ ノ ヤクワリ ト コウサンカ ブッシツ セッシュ ノ エイキョウ

Role of ultraviolet A（UVA）on oxidative damage has attracted much attention in relation to skin photoaging process. In this study, we investigated effect of cholesterol hydroperoxides（Chol- OOHs）, stable products of reactive oxygen species（ROS）-induced lipid peroxidation, on matrix metalloproteinase（MMP）activation responsible for wrinkle formation in hairless mouse skin and then estimated the inhibition of UVA-induced MMP activation by dietary β-carotene. Hairless mice were exposed to UVA irradiation for 8 weeks. Chol-OOHs content in the skin was found to increase significantly by the exposure of UVA. In addition, the activity of MMP-9 and its protein expression were elevated with wrinkle formation. This activation was also induced by intracutaneous injection of Chol-OOHs. Interestingly, dietary β-carotene（500 mg/kg diet） and α-tocopherol （100 mg/kg diet）suppressed the accumulation of Chol-OOH as well as MMP activation. These results suggest that Chol-OOHs formed by the exposure of UVA to skin contribute to the activation of MMPs resulting in skin photoaging. Dietary antioxidants may prevent skin photoaging through, at least partly, the suppression of MMP activation due to UVA-induced lipid peroxidation

金属微粒子の相変態特性

京都大学0048新制・論文博士理学博士論理博第61号新制||理||37(附属図書館)671(主査)教授 可知 祐次, 教授 高木 秀夫, 教授 水渡 英二学位規則第5条第2項該当Kyoto UniversityDA

Electric Field Effects in Ultrathin YBa2Cu3O7-d Films (SOLID STATE CHEMISTRY-Artificial Lattice Compounds)

Charging effects on transport properties of ultrathin YBa2Cu3O7-d (YBCO) films are measured using FETlike junctions of YBCO in thickness ranging from 1 to 10 unit cell thicknesses (UCT). An electric(E-) field experiment without magnetic field finds that the changes of Kosterlitz-Thouless transition temperature is observed as a function of applied E-field. The changes of superconducting properties are linearly correlated to those of the normal resistance, namely, the induced areal carrier densities