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        검색결과 9

        1.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 북극과 남극에서 기온과 수온이 영하임에도 불구하고 얼음이 없는 광범위한 지역(인공증빙가능역) 이 존재하는 것에 주목하여, 이 지역에 인공적으로 해빙을 생성하여 지구 표면의 알베도를 높이는 방식으로 지구온난화 를 완화하는 방법을 제안하였다. 대략 4.09×106 km2의 해빙면적이 추가되면 지구온난화 효과로 가정되는 약 0.85Wm−2 에너지가 상쇄된다고 계산되었다. 또한, 인공적으로 해빙을 생성하기 위한 세 가지 빙판 생성 방법(배로 물 뿌리기, 빙 판생성장치 운용, 수면에 GCF부유물질 띄우기)을 제안하였다. 간단한 에너지평형모형 실험에 따르면, 3개월 (9, 10, 11 월) 동안 인공증빙가능역에 해빙을 최대로 생성할 경우, 다음해에 대략 0.11oC의 지구표면온도 하강이 기대되었다. 반면 에 모든 계절을 통해 생성할 경우, 오히려 지구 냉각화를 초래할 위험성도 발견되었다.
        4,200원
        6.
        2017.08 KCI 등재 서비스 종료(열람 제한)
        Background: The present study was carried out to asses whether mulberry leaves (MLs) have the potential to inhibit the mutagenic effect of cigarette smoke condensates (CSCs). Methods and Results: ML powder was extracted with 70% ethanol, and a yield of 35.1% by weight was obtained. The 70% ethanol extract of ML was further extracted sequentially using diethyl ether, chloroform, butanol, dichloromethane and water. The crude 70% ethanol extract of MLs and its solvent fractions did not show any mutagenic effect when tested at concentrations up to 1 ㎎/ plate against Salmonella typhimurium TA98. In contrast, the crude 70% ethanol extract showed an inhibitory activity against the mutagenicity of CSCs in the presence of S-9 mixture. Among the solvent fractions, the diethyl ether fraction showed the highest inhibitory activity, which increased in a dose-dependent manner, inhibiting mutagenesis by approximately 97.1% at a concentration of 1㎎/plate. Conclusions: In this study, we found that a crude 70% ethanol extract of MLs and the diethyl ether fraction themselves are potentially not mutagenic, but inhibit the mutagenic effect of CSCs.
        7.
        2017.05 서비스 종료(열람 제한)
        Background : The effects of heat treatments on the phycochemical charateristics and antioxidant activities of ginkgo nuts were investigated by roasting at various temperatures (150, 180, and 210℃) for 60 min. Methods and Results : For each roasting temperatures, pH, total acidity, chromaticity, total cyanide content, reducing power, total polyphenol content, 2,2’-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities were compared and analyzed. As the roasting temperature and time increased, the pH and total cyanide content decreased from 7.32 to 6.31 and from 697 to 282 ㎍/㎎, respectively, while total acidity increased from 0.40 to 0.84%. There was an 11 or more color difference (ΔE) between the non-heated ginkgo nut and heated ginkgo nuts, indicating a remarkable color difference. The antioxidant activities, including reducing power, total polyphenol content, and DPPH and ABTS radical scavenging activities increased rapidly at 210℃ according to increasing in roasting temperature and time. Conclusion : These results suggest that the ginkgo nut with heat treatment could be used in food materials and medicines for decreasing cyanide content as well as for increasing antioxidant compound content.
        8.
        2017.05 서비스 종료(열람 제한)
        Background : F. fomentarius extracts have been recently reported to process immune-stimulatory and anti-inflammatory effects. In this study, we evaluated the anti-mutagenic effect of F. fomentarius ethanol extracts and the effective chemical components from the extract were analyzed by LC-Q-TOF. Methods and Results : F. fomentarius was extracted with 70% ethanol yielding a crude extract 6.8%. The crude extract was fractionated sequentially to diethyl ether, chloroform, dichloromethane, butanol and water with a yield of 43.9%, 2.958%, 6.8%, 21.6% and 25.5.%, respectively. The anti-mutagenic effect of F. fomentarius extract and its fractions was tested in Ames test by two type of Salmonella typhimurium (TA98 and TA100). Among the five fractions, diethyl ether has shown the highest and significant anti-mutagenic effect (98.3%, at 3,000 ㎍/plate concentration). Moreover, we investigated the chemical constituents of the extract using UPLC-Q-TOF. A total of 10 compounds such as flavonoids (velutin, 3, 4′,5-Trihydroxy-3′,7-dimethoxyflavanone) and fatty acids (γ-linoleic acid, stearic acid) and deterpenoid (kirenol) were tentatively identified with an accurate mass within 10 ppm mass error. Also, flavonoids and fatty acids were detected with higher rate than other compounds based on obtained chromatograms. Conclusion : We demonstrated that F. fomentarius extract and fractions have anti-mutagenic activity through Ames test. Furthermore, we will carry out isolation of each components from its fraction and use them to conduct additional anti-mutagenic test.
        9.
        2016.10 서비스 종료(열람 제한)
        Background : Recently, many studies to seek for medicinal herb compounds from natural products have been attempted capable of being free from harmful side effects and reducing the economic burden. This study was conducted to investigate whether Morus alba L.(MAL) water extracts has a biological safety, and an inhibitory potential against the mutagenicity induced by cigarette smoke condensates(CSC). Methods and Results : MAL was extracted with 70% ethanol and the yield of the extract was 35.1%. The 70% ethanol MAL extract was fractionated sequentially by diethylether, chloroform, dichloromethane, and water, respectively. Crude MAL 70% ethanol extract itself and its solvent fractions did not show any mutagenic effect up to 1 mg/plate toward Salmonella typhimurium TA 98 with or without the microsomal S-9 mixture of liver metabolic activations. On the other hand, the crude MAL extract showed an inhibitory activity against the mutagenicity of CSC with S-9 mixture. Diethyl ether layer among five solvent fractions showed the highest inhibitory activity at the same dose. The inhibitory activity of diethyl ether layer was also increased dose-dependently and the inhibitory rate was about 97.1% at the concentration of 1 mg/plate. Conclusion : In this study, we concluded that all of the crude MAL 70% ethanol extract and its solvent layers are potentially safe for mutagenicity and the diethyl ether layer among the crude MAL 70% ethanol extract has an inhibitory effect against the mutagenicity of CSC.