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        검색결과 5

        1.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Red meats are important animal foods because of their nutritional aspects, but the over-consumption of red meat produces reactive oxygen species (ROS) caused by heme iron and induces colorectal cancer. The effect of orally administered hemin and calcium provided in drinking water for 6 weeks on colon carcinogenesis was observed in male ICR mice. After the mice were acclimated for 1 week, they received three subcutaneous azoxymethane (AOM, 10 mg/kg b.w.) injections weekly and were provided with 2% dextran sodium sulfate (DSS) via drinking water for the next week. The mice were divided into three groups: the control, hemin, and hemin + calcium groups. The orally administered daily dose of hemin was 2 g/kg b.w., and 0.05% calcium was provided daily via drinking water. Colonic mucosa samples were stained with methylene blue, and then, the numbers of aberrant crypt (AC) and aberrant crypt foci (ACF) were counted. Lipid peroxidation in feces was estimated by thiobarbituric acid-reactive substances (TBARS) assay. The total numbers of AC and ACF per colon in the hemin group were significantly higher than those in the control group. Calcium treatment significantly decreased the numbers of ACF and AC in the colon of mice. The TBARS value in the feces of the hemin + calcium group was significantly lower than that in the feces of the hemin group. These results showed that hemin enhances the formation of pre-neoplastic lesions in the colon of mice and that calcium decreases the risk of colon carcinogenesis.
        4,000원
        3.
        1998.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Base isolation is an innovative design strategy that provides a practical alternative for the seismic design of structures. Base isolators, mainly employed to isolate large structures subjected to earthquake ground excitations and to rehabilitate structures damaged by past earthquakes, deflect and absorb the seismic energy horizontally transmitted to the structures. This study demonstrated that the base isolation system may offer effective performance for bridges during severe seismic events through shaking table tests. Two base isolation systems using laminated rubber bearings with and without hydraulic dampers are tested. The test results strongly show that the laminate rubber bearings cause the natural period of the bridge structure increased considerably, which results in the deck acceleration and the shear forces on the deck acceleratino and the shear forces on the piers reduced significantly. The results also demonstrate that the hydraulic dampers enhance the system's capacity in dissipating energy to reduce the relative displacement between the bridge deck and the pier.
        4,000원
        4.
        2017.05 서비스 종료(열람 제한)
        Background : This study was conducted to examine the suitability of the blue/white vinyl for ginseng cultivation greenhouses in different regions in an effort to develop a stable ginseng cultivation technology and contribute to popularizing ginseng greenhouse farming. Methods and Results : For comparison purposes, ginseng plants were cultivated in the traditional shading and greenhouse shading facilities. The average temperature in the greenhouse shading facilities during the period of May through October was 20.5℃ in Namwon, 21.4℃ in Jinan, and 23.3℃ in Iksan, with Iksan recording a 1.9–2.8℃ higher average temperature, presumably due to its location in a plain area with low elevation. The average temperatures in the traditional shading facilities ranged between 22.9℃ and 25.7℃, 2.4–2.6℃ higher compared with the greenhouse shading facilities. As for the incidence of disease and pest, as low as 0.1–0.3% of the plants grown under greenhouse shading were infected with Colletotrichum dematium, Alternaria panax, and Rhizoctonia solani, whereas much higher incidences were noted in the control plants, with 3.3–11.3%, 4.7–17.0%, 0.1–0.5%, and 3.0–5.7% infected with Colletotrichum dematium, Alternaria panax, Rhizoctonia solani, and Phytophthora cactorum, respectively, throughout the regions. Heat injury occurred only in Iksan (0.3%) in the case of greenhouse-shaded plants, whereas the control plants suffered from much severer heat injury: 3.5% in Namwon, 10% in Jinan, and as high as 35.3% in Iksan. As for the roots, Namwon outperformed other regions in root length (29.7 ㎝), taproot length (8.7 ㎝), and taproot diameter (25.3 ㎜), and also the root fresh weight (53.4 g), followed by Jinan (48.7 g) and Iksan (40.4 g). In yield as well, the greenhouse in Namwon outperformed other regions with 1,297㎏/10a, followed by Jinan (1,183 ㎏) and Iksan (932 ㎏). The effect of greenhouse blue-white vinyl shading on yield by region was analyzed to increase of 177% in Namwon, 209% in Jinan, and 173% in Iksan with respect to their respective traditional shading facilities. Conclusion : The suitability of the blue/white vinyl shading in ginseng cultivation greenhouses was tested experimentally in three different regions. As a result, greenhouse-shaded ginseng plants were found to be much less affected by heat injury compared with traditionally shaded ginseng plants, resulting in much higher yields in all regions. This allows the conclusion that greenhouse ginseng cultivation can contribute to more stable ginseng yield and popularization of ginseng cultivation.