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        검색결과 62

        44.
        2015.06 KCI 등재 서비스 종료(열람 제한)
        In this study, we tried to offer the possibility of White Hibiscus syriacus L. (WHS) flower extracts as a preven-tive and improving agent of osteoporosis that bone mass reduction is induced by an decrease of osteoblast involved in boneformation and increase of bone resorption by osteoclast activity. As a results, it was found to have antioxidant activity andcontain a flavonoid contents (47.74㎎/g) of the WHS flower. There was cytotoxicity at more than 250㎍/㎖ concentration ofWHS flower extract of RANKL-induced osteoclast in RAW264.7. There were no significant inhibited TRAP activity in theWHS leaf and stem. However, it was confirmed that it is significantly inhibited the differentiation activity of osteoclasts in 50and 100㎍/㎖ concentration of cells of stability levels of only WHS flower extracts (p<0.01). The WHS flower prominentlyinhibited RANKL-induced osteoclast differentiation activity by decreased calcitonin receptor and TRAP mRNA (p<0.01).These results indicate that of osteoclasts differentiation activity is inhibited by protection of oxidative stress due to the anti-oxidant activity of the WHS flower. Therefore, suggesting the WHS flower may be a presents the possibility as a preventiveand therapeutic agents for osteoporosis.
        46.
        2015.04 KCI 등재 서비스 종료(열람 제한)
        This study was carried out to evaluate the preventive effect of three forms of Korean ginseng roots (fresh, white and red) against bisphenol A (BPA) toxicity in mouse male germ cells (GC-2spd, TM3, TM4). ROS (reactive oxygen species) generation were measured by DCF-DA (2’,7’-dichlorohydrofluorescein diacetate) assay. Also, semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) was performed to quantify the mRNA expression levels of apoptosis- related genes, Bax (pro-apoptotic gene) and Bcl2 (anti-apoptotic gene). ROS generation was increased by 50 μM BPA, but definitely decreased by treatment with Korean ginseng extracts (fresh, white and red) in mouse male germ cells. In especial, Korean fresh ginseng extract reduced significantly ROS production to normal control. In addition, Korean fresh and white ginseng extracts suppressed the apoptosis of mouse male germ cells by fine-tuning mRNA levels of apoptotic genes changed by BPA. In general, Korean fresh ginseng extract was more effective than white ginseng extract for reducing BPAinduced oxidative stress and apoptosis in mouse male germ cells. Therefore, Korean fresh and white ginseng may help to alleviate biphenol A toxicity in mouse male germ cells.
        47.
        2015.04 KCI 등재 서비스 종료(열람 제한)
        Osteoporosis induces a bone mineral density loss due to imbalance of bone homeostasis that is achieved by osteoclasts (which are involved in bone resorption) and osteoblasts (which are involved in bone formation). Thus, this study was performed to evaluate the effects of hot water extract of the Achyranthes bidentata Blume (ABB) and Panax ginseng (Gin) on osteoclast and osteoblast differentiation. In this study, there was no cytotoxicity by ABB, 50 and 100 μg/ml of Gin significantly decreased cell viability of RANKL-induced osteoclast in RAW264.7 cell (p < 0.01). But, it was 50 μg/ml of ABB and Gin mixtures increased due to protective action of ABB. Furthermore, Gin contained groups (Gin, ABB and Gin mixtures) were inhibitory effects on osteoclast differentiation and bone resorption, and increased in osteoblast differentiation activity. Gin clearly inhibited RANKL-induced osteoclast differentiation by decreased calcitonin and TRAP (p < 0.01). Also, these extracts significantly increased calcium accumulation formation of osteoblastic differentiation reagents-induced osteoblast in MC3T3-E1 cell (p < 0.05). These results suggest that ABB and Gin mixtures may be a potential as drug for the treatment of osteoporosis.
        50.
        2014.04 KCI 등재 서비스 종료(열람 제한)
        Quantitative assessment of groundwater level change under extreme event is important since groundwater system is directly affected by drought. Substantially, groundwater level fluctuation reveals to be delayed from several hours to few months after raining according to the aquifer characteristics. Groundwater system in Jeju Island would be also affected by drought and almost all regions were suffered from a severe drought during summer season (July to September) in 2013. To estimate the effect of precipitation to groundwater system, monthly mean groundwater levels in 2013 compared to those in the past from 48 monitoring wells belong to be largely affected by rainfall(Dr) over Jeju Island were analyzed. Mean groundwater levels during summer season recorded 100 mm lowered of precipitation compared to the past 30 years became decreased to range from 2.63 m to 5.42 m in southern region compared to the past and continued to December. These decreasing trends are also found in western(from –1.21 m to –4.06 m), eastern(-0.91 m to –3.24 m), and northern region(from 0.58 m to –4.02 m), respectively. Moreover, the response of groundwater level from drought turned out to be –3.80 m in August after delaying about one month. Therefore, severe drought in 2013 played an important role on groundwater system in Jeju Island and the effect of drought for groundwater level fluctuation was higher in southern region than other ones according to the regional difference of precipitation decrease.
        51.
        2013.05 KCI 등재 서비스 종료(열람 제한)
        Over 96.2% of the agricultural water in Jeju Island is obtained from groundwater and there are quite distinct characteristics of agricultural water demand/supply spatially because of regional and seasonal differences in cropping system and rainfall amount. Land use for cultivating crops is expected to decrease 7.4% (4,215 ha) in 2020 compared to 2010, while market garden including various vegetable crop types having high water demand is increasing over the Island, especially western area having lower rainfall amount compared to southern area. On the other hand, land use for fruit including citrus and mandarin having low water demand is widely distributed over southern and northern part having higher rainfall amount. The agricultural water demand of 1,214×10 3 ㎥/day in 2020 is estimated about 1.39 times compared to groundwater supply capacity of 874×10 3 ㎥/day in 2010 with 42.4% of eastern, 103.1% of western, 61.9% of southern, and 77.0% of northern region. Moreover, net secured amount of agricultural groundwater would be expected to be much smaller due to regional disparity of water demand/supply, the lack of linkage system between the agricultural water supply facilities, and high percentage of private wells. Therefore, it is necessary to ensure the total net secured amount of agricultural groundwater to overcome the expected regional discrepancy of water demand and supply by establishing policy alternative of regional water supply plan over the Island, including linkage system between wells, water tank enlargement, private wells maintenance and public wells development, and continuous enlargement of rainwater utilization facilities.
        52.
        2013.05 KCI 등재 서비스 종료(열람 제한)
        Fluctuation patterns of groundwater level as a factor that reflects the characteristics of groundwater system can be categorized as the various types of aquifer with the time-series data. Time-series data on groundwater level obtained from 115 monitoring wells in Jeju Island were classified according to variation types, which were largely affected by rainfall(Dr), rainfall and pumping(Drp), and unknown cause(De). Analysis results indicate that 106 wells belong to Dr and Drp and the ratio of the wells with the wide range of fluctuation in the western and northern regions was higher than that in the eastern and southern regions. From the results that Drp is relatively higher than Dr in the western region which has the largest agricultural areas, groundwater level fluctuations may be affected significantly due to the intensive agricultural use. Non-parametric trend analysis results for 115 monitoring wells show that the increasing and decreasing trends as the ratio of groundwater levels were 14.8% and 22.6%, respectively, and groundwater levels revealed to be increased in the western, southern and northern regions excluding eastern region. Results of correlation analysis that cross-correlation coefficients and the time lags in the eastern and western regions are relatively high and short, respectively, indicate that the rainfall recharge effect in these regions is relatively larger due to the gentle slope of topography compared to that in the southern and northern regions.
        53.
        2013.04 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The phenolic compounds of water extracts from Prunella vulgaris were highest at 9.25 mg/g, respectively, when various extraction solvents were used. The optimum condition for extracting phenolic compounds from Prunella vulgaris was extraction in water for 18hr. The DPPH-scavenging activities of Prunella vulgaris were highest at the water extracts. The ABTS radical cation decolorization was higher than 40% in the range of 0~100% ethanol extract section. The antioxidant protection factor on the lipophilic phenolic metabolites was shown to be 1.1 PF in the water extracts from Prunella vulgaris. The TBARS was lower than the control (0.53 μM) in all the sections. The tyrosinase inhibitory effect, which is related to skin whitening, was above 40%, and for the anti-wrinkle effect, the elastase inhibition activity was above 40% at 0.2 mg/mL. The astringent effect of the Prunella vulgaris 40%ethanol extracts was 98.1% at 1 mg/mL. As a result, it can be concluded that Prunella vulgaris has the potential to be used as a cosmetic material.
        54.
        2011.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        자색 고구마로부터 페놀성 화합물 추출 최적 조건은 50% 에탄올로 12시간 추출하였을 때 최대 용출량을 나타내었다. 불과 50% 에탄올을 용매로 하여 제조한 자색 고구마 종류별 추출물의 항산화 활성 측정 결과 전자공여능, ABTS, PF 측정에서 일반 고구마에 비하여 자색 고구마 자미, 신자미, 연자미 품종 모두 높게 나타났으며, TBARs 측정결과 모든 추출물에서 30% 이하로 낮은 TBARs 생성 억제활성을 나타내었다. 피부상재균에 대한 최소
        57.
        2008.08 KCI 등재 서비스 종료(열람 제한)
        Nowadays, research on human-robot interaction has been getting increasing attention. In the research field of human-robot interaction, speech signal processing in particular is the source of much interest. In this paper, we report a speaker localization system with six microphones for a humanoid robot called MAHRU from KIST and propose a time delay of arrival (TDOA)-based feature matrix with its algorithm based on the minimum sum of absolute errors (MSAE) for sound source localization. The TDOA-based feature matrix is defined as a simple database matrix calculated from pairs of microphones installed on a humanoid robot. The proposed method, using the TDOA-based feature matrix and its algorithm based on MSAE, effortlessly localizes a sound source without any requirement for calculating approximate nonlinear equations. To verify the solid performance of our speaker localization system for a humanoid robot, we present various experimental results for the speech sources at all directions within 5 m distance and the height divided into three parts.
        58.
        2005.02 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        건조분말두부의 열풍, 진공 및 동결 건조방법에 따른 흡습특성과 평형수분함량 예측의 회귀식을 도출하였다. 단분자층 수분함량은 GAB식이 더 높은 유의성을 보였으며 수분흡습을 위한 엔탈피, 자유에너지, 엔트로피의 변화는 큰 차이는 없었으나 수분활성도가 0.11에서 0.93으로 증가할수록 흡습엔탈피의 값은 감소하였으며 등온흡습곡선의 경우 수분활성도가 증가할수록 수분함량이 높아졌으며 수분 활성도가 높을수록 필요로 하는 흡습에너지가 낮아져 흡습이 쉽게 이
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