1) In this study, the canadian peat moss extract was purified by a supercritical CO2 using three different conditions and assessed its biological activities. Peat moss was extracted by acid-alkaline extraction method (sample 1) and purified by a supercritical CO2 at 40℃ under pressure of 100 bar (sample 2), 120 bar (sample 3) or 150 bar (sample 4). We evaluated the antioxidant activities of the samples by 1,1diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging, Fe 2+ / ascorbate (FTC) and 2-thiobarbituric acid (TBA) methods. The antioxidant activities were examined by comparing the results with that of ascorbic acid as a positive control. Sample 3 showed relatively higher DPPH radical-scavenging activities than other samples. The antioxidant activity by FIC method exhibited similar results as the DPPH radicalscavenging activities. On the other hand, sample 2 showed higher antioxidant activity measured by TBA method of all. The whitening effects of the samples were examined using mushroom tyrosinase and B16F10 melanoma cells. Sample 3

1) Five yeast strains were isolated from traditional Makgeollies, Makgeollies were made by isolated yeasts after cultivation, and then property changes of Makgeollies were analyzed according to yeasts, storage temperatures and storage periods. Average pHs were shown to be 3.22~3.88 and statistically changed according to yeasts used, storage temperatures and storage periods. Total acidities were statistically changed according to storage periods. Amino-type nitrogen contents were in the ranges of 0.009~0.245% and statistically changed according to storage temperatures especially at 18 and 25℃ for 15 days. Average alcohol concentrations were in the ranges of 7.5~18.5% and reduced until 10 days and increased for 15 days according to yeasts used and storage periods. Consequently, Makgeollies, made by isolated yeast strains originated from traditional Makgeollies, revealed that alcohol concentrations and amino-type nitrogen contents were changed but pHs and total acidities were not dramatically changed according to yeasts used. It suggests 1 신라대학교 대학원 생명공학과

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We present the detection characteristics of nitrogen monoxide(NO) gas using p-type copper oxide(CuO) thin film gas sensors. The CuO thin films were fabricated on glass substrates by a sol-gel spin coating method using copper acetate hydrate and diethanolamine as precursors. Structural characterizations revealed that we prepared the pure CuO thin films having a monoclinic crystalline structure without any obvious formation of secondary phase. It was found from the NO gas sensing measurements that the p-type CuO thin film gas sensors exhibited a maximum sensitivity to NO gas in dry air at an operating temperature as low as 100 o C. Additionally, these CuO thin film gas sensors were found to show reversible and reliable electrical response to NO gas in a range of operating temperatures from 60 o C to 200 o C. It is supposed from these results that the ptype oxide semiconductor CuO thin film could have significant potential for use in future gas sensors and other oxide electronics applications using oxide p-n heterojunction structures.