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        검색결과 35

        25.
        2019.03 KCI 등재 서비스 종료(열람 제한)
        In this study, the impacts of local meteorology caused by tidal changes in the West Sea on ozone distributions in the Seoul Metropolitan Area (SMA) were analyzed using a meteorological model (WRF) and an air quality (CMAQ) model. This study was carried out during the day (1200–1800 LST) between August 3 and 9, 2016. The total area of tidal flats along with the tidal changes was calculated to be approximately 912 km2, based on data provided by the Environmental Geographic Information Service (EGIS) and the Ministry of Oceans and Fisheries (MOF). Modeling was carried out based on three experiments, and the land cover of the tidal flats for each experiment was designed using the coastal wetlands, water bodies (i.e., high tide), and the barren or sparsely vegetated areas (i.e., low tide). The land cover parameters of the coastal wetlands used in this study were improved in the herbaceous wetland of the WRF using updated albedo, roughness length, and soil heat capacity. The results showed that the land cover variation during high tide caused a decrease in temperature (maximum 4.5℃) and planetary boundary layer (PBL) height (maximum 1200 m), and an increase in humidity (maximum 25%) and wind speed (maximum 1.5 ms-1). These meteorological changes increased the ozone concentration (about 5.0 ppb) in the coastal areas including the tidal flats. The increase in the ozone concentration during high tide may be caused by a weak diffusion to the upper layer due to a decrease in the PBL height. The changes in the meteorological variables and ozone concentration during low tide were lesser than those occurring during high tide. This study suggests that the meteorological variations caused by tidal changes have a meaningful effect on the ozone concentration in the SMA.
        26.
        2018.06 KCI 등재 서비스 종료(열람 제한)
        Multifunctional weirs constructed through the Four Major Rivers Restoration Project are operated as management water levels. The purpose of this study was to evaluate the effect of water level in the main stem on the tributary water level according to multifunctional weir operation, because the operation of multifunctional weirs for water level management influences the drainage of tributaries. In this study, water level pressure gauges were installed and spatial and temporal water quality was observed. The LOcally Weighted Scatterplot Smoothing (LOWESS) technique was applied to the Nakdong River and the Baekcheon Junction, both upstream of the Gangjeong-Goryeong weir, in order to analyze water quality trends. When considering the overall analysis and observations, it was found that the water quality forecasting point located at the Baekcheon estuary point should be transferred to the Dosung Bridge, which is located upstream of the Sunwon Bridge.
        27.
        2018.04 서비스 종료(열람 제한)
        We evaluated the efficacy and safety of plasmakinetic transurethral enucleation and resection (TUERP) for benign prostatic hyperplasia (BPH) more than 80g. From January 2011 to December 2013, 37 patients with BPH larger than 80 g who underwent plasmakinetic TUERP were retrospectively assessed. The postoperative outcomes such as operative time, resected adenoma weight, resection rate, catheterization time, postoperative hospital stay and complications were reviewed. Patients were followed up at 1, 3, 6 months postoperatively. The mean prostate volume was 108.7 ± 21.7 g (range, 80 to 200 g), The mean resection chip weight was 53.5 ± 15.7 g (range, 29 to 101 g), The mean resection ratio was 82.0 ± 12.9%. Catheterization time and hospital stay was 2.4 ± 1.6 days and 3.4 ± 1.6 days respectively. Perioperative loss of hemoglobin and serum sodium was 1.5 ± 0.8 g/dL and 2.3 ±2.0 mmol/L respectively. International Prostate Symptom Score (IPSS), quality of life (QOL) score, maximum flow rate (Qmax), post void residual urine volume (PVR) were significantly improved at all followup intervals compared with baseline. No major complication including TUR syndrome was developed. Plasmakinetic TUERP is considered a safe, effective and technically feasible procedure for the large volume BPH more than 80 g at shortterm followup.
        28.
        2016.10 서비스 종료(열람 제한)
        Background : Some of invasive plants, which were introduced from foreign countries, have caused problems in Korea. Invasion of these invasive plants in the ecosystem threatens the habitat of endemic species, reducing biodiversity, and causing a disturbance in the ecological system. Hypochaeris radicata L. (Asteraceae), the most invasive plants in Korea, particularly in Jeju Island, invade farmland, and autochthonous forest, establishing monocultures and modifying the ecosystem structure. This invasive species has become a serious environmental problem because they displace the indigenous plant species. This study was conducted to evaluate the antioxidantive effects of ethanolic extracts from different parts (root, stem, seed and leaf) of the invasive exotic species Hypochaeris radicata L. Methods and Results : The aim of present study was to estimate the total phenolic and flavonoid contents and to investigate in vitro antioxidant potential of ethanolic leaf, root, seed, and stem extracts of the Hypochaeris radicata. Antioxidant activity was assessed by using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay, reducing power activity, [2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid)] ABTS+ assay and ferrous ion chelating activity. The total phenolic and flavonoid contents were also determined and expressed in gallic acid and quercetin equivalent respectively. The results of the study indicate that the ethanolic extracts of the leaf, root, seed, and stem of H. radicata posses significant scavenging activity against DPPH (21.25% for leaf, 34.98% for root, 60.76% for seed and 45.25% for stem at 250 μg/ml each) and ABTS+ radical scavenging activity (14.85% for leaf, 17.40% for root, 35.91% for seed and 24.70% for stem at 250 μg/ml each), reducing power activity (0.178 absorbance at 300 μg/ml for leaf, 0.211 absorbance at 300 μg/ml for root, 0.447 absorbance at 300 μg/ml for seed, 0.276 absorbance at 300 μg/ml for stem). The free radical scavenging and antioxidant activities may be attributed to the presence of adequate phenolic (gallic acid content is 361.92.98 μg/g in leaf, 356.59μg/g in root, 719.72 μg/g in seed and 512.08 μg/g stem) and flavonoid compounds (219.52 μg/g in leaf, 75.67μg/g in root, 281.39 μg/g in seed and 215.66 μg/g stem). This study revealed that the ethanolic extracts of both leaf, root, seed and stem of H. radicata has demonstrated significant antioxidant activity. Conclusion : In conclusion, the present study has demonstrated that Hypochaeris radicata seed ethanol extracts are rich in phenolics and have a strong antioxidant activity and a radical-scavenging action in all of the tested methods. This suggests that Hypochaeris radicata is a good source of natural antioxidants.
        29.
        2016.10 서비스 종료(열람 제한)
        Background : More than 1250 bamboo species, belonging to 75 genera, are distributed all over the world. Sasa quelpaertensis Nakai is a type of bamboo grass widely distributed in Halla mountain, Jeju Island, which has been used as antidiabetic, anti-cancer and anti-inflammatory drugs. In this study, we investigated the antioxidant and antimicrobial activities of Sasa quelpaertensis Nakai leaf extracted with different ethanol concentration and demonstrated the potent bioactivities of the extracts suitable to be used as natural antioxidant compounds or pharmaceutical supplements. Methods and Results : Antioxidant and anti-microbial activities of Sasa quelpaertensis Nakai extracts were studied. At first, different ethanol concentrations (0, 20, 40, 60 and 80%) were compared for determining of the best solvent for extraction of phenolic compounds from Sasa quelpaertensis Nakai. Forty percent Ethanol extract with 990.01±28.9 (mg of gallic acid equivalents/g sample) were the best solvent in the extraction of phenolic compounds. But, 60% ethanolic extracts were highest antioxidant activity appeared such as DPPH radical scavenging (IC50 21.20±0.42 μg/ml), ABTS radical scavenging (IC50 49.85±1.27 μg/ml) and reducing power. However, 80% ethanol extracts showed the strongest SOD like activity. The anti-microbial capacity was screened against Gram positive and Gram negative bacteria, and yeast. Sixty percent and 80% ethanol extracts inhibited the growth of Gram positive bacteria; Bacillus cereus was the most susceptible one with MIC of 125 μ g/ml and 250 μg/ml for the 60% and 80% extracts, respectively. Conclusion : The results of this study show that the extract of Sasa quelpaertensis Nakai can be used as easily accessible source of natural antioxidants and as a possible food supplement or in pharmaceutical industry. However, the components responsible for the antioxidant and antimicrobial activities of both extracts of Sasa quelpaertensis Nakai are currently unclear. Therefore, it is suggested that further works should be performed on the isolation and identification of the antioxidant components in Sasa quelpaertensis Nakai.
        30.
        2016.05 서비스 종료(열람 제한)
        Backgrounds : Pomelo (Citrus grandis Osbeck) is the kind of citrus fruit which is Dicotyledoneae belongs to Rutaceae and special product in Jeju island. According to the previous researches, coumarin, eliocitrin, naringin are identified and these kinds of constituents revealed to be effective as anticancer, antioxidant, and antidiabetic. Until recently, there are many investigations about its functional properties were reported, but investigation about biological activities depend on extraction conditions are not sufficient. Methods and Results : 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was performed by the method of Blois with minor modification. After adding DPPH radical to each sample solutions, the mixtures were incubated in 30 minutes at aphotic place. Then, the degree of scavenging activity was recorded by microplate reader at 490 nm. The scavenging activity was expressed by RC50, which is the concentration of sample solution necessitated to scavenge 50% DPPH radical against negative control. For α-glucosidase inhibitory activity, the method using p-nitrophenyl-α-D-glucopyranoside (pNPG) was applied. To each samples, α-glucosidase and pNPG were mixed and incubated, consequently, Na2CO3 was added to terminate the reaction. Finally, absorbance was read at 450 nm. The same as DPPH radical scavenging activity, the inhibition was explicitly expressed by the amount of sample solution to inhibit 50% α-glucosidase, IC50. The 80% MeOH extract demonstrated the highest radical scavenging activity with 74.32±8.45 μg/ml. α-Glucosidase inhibitory activity was carried out to evaluate the inhibitory activity of sugar digestion and absorption and 60, 80% MeOH extract exhibited 416.35±11.07 μg/ml and 336.57±2.03 μg/ml, respectively. Conclusion : The DPPH radical scavenging and α-glucosidase inhibitory activity were evaluated in this study. The highest DPPH radical scavenging activity was seen in 80% Citrus grandis Osbeck MeOH extract, following 60% MeOH extract exhibited the second highest scavenging activity. Also, 80% MeOH extract showed 336.57±2.03 μg/ml, which was the highest α-glucosidase inhibition among all extracts.
        31.
        2015.07 서비스 종료(열람 제한)
        Ionizing radiation directly and indirectly affects gene expression within the plant genome. To access the physiological response of rice to different types of ionizing radiation, rice seeds were exposed to gamma-ray and ion beam radiation. Exposure to ionizing radiation dramatically decreased the shoot length compared with non-irradiated plants. Fluorescence-activated-cell-sorting (FACs) was used to measure DNA contents. There were significant correlations of dose-dependent between irradiated plant and non-irradiated plant. The radicals induced by the ionizing radiation in the plant could be observed by electron spin resonance (ESR). It was confirmed that the number of free radicals in cell was greatly increased all irradiated plants than non-irradiated plant. A significant positive correlation was shown between ionizing radiation dose and signal intensity. In order to determine the Genetic diversity, AFLP analysis was conducted with the irradiated plant and non-irradiated plant. Based on band patterns, the cluster analysis was conducted to evaluate the genetic variation by using the UPGMA (Unweighted Pair Grouping Method of Averages). Genetic diversity of irradiated plants by low dose ion beam was the closest non-irradiated plant and irradiated by high dose gamma-ray was the furthest from non-irradiated. We describe the detailed methods of ionizing irradiation and discuss its applications in genetic research as well as plant breeding.
        33.
        2011.06 KCI 등재 서비스 종료(열람 제한)
        한국 춘란의 재배가 난애호인의 정서에 미치는 영향에 대하여 알아보고자 한국춘란을 재배 해 온 난애호인을 대상으로 춘란 재배 관련 사항, 춘란 보유 상황, 재배 시 어려운 점, 재배를 통해 얻게 된 점 등에 대하여 설문을 실시하였고 난애호인의 정서 변화를 알아보기 위해 자긍심 척도를 사용하여 결과를 분석하였다. 한국 춘란을 재배해 온 난애호인 402명의 일반적 특성으로는 남성의 비율이 92.0%로 높았으며 연령대는 50대가 50.4%로 높았으며 난의 가치에 대한 응답 결과, 춘란을 반려식물로 인식하는 경우가 26.3%, 문화․예술적 가치 24.6%, 심리적 자긍심 19.8%, 외형적 아름다움 14.4%, 경제적 가치 12.8%, 기타 1.5%로 4.6다. 춘란을 기르면서 자긍심을 느끼게 된 경우에 있어서는 전시회에 출품 할 때 62.9%, 정보 매체를 통해서 16.6%, 춘란 품종을 등록했을 때 9.0%, 고문서 또는 고서화 등 책을 통해 8.5%, 기타 0.3%로 나타났다. 난 기르기에 의해 얻어진 자신감과 자긍심과의 상관계수는 0.26, 재배를 통해 얻어진 행복감과 자긍심의 상관계수는 0.30, 만족감과 자긍심의 상관계수는 0.28로써 모두 유의수준 0.01하에서 유의한 결과로 나타났다. 즉, 한국 춘란 재배에 따라 난애호인의 자긍심에 변화가 있는 것으로 나타났으며 이는 춘란 재배를 통해 얻어진 자신감과 행복감, 만족감 등의 긍정적인 정서는 난애호인으로 하여금 자신에 대해 느끼는 자긍심에 영향을 주고 있음을 알 수 있었다. 한국 춘란을 재배한 기간에 따라 자긍심을 느끼는 차이를 조사한 결과, 재배 기간이 1년 미만인 경우에 자긍심을 매우 많이 느끼고 있는 경우는 12.50% 이었으며 3년 미만인 경우는 10.0%, 5년 미만 13.33%, 10년 미만 14.89%, 10년 이상 34.54%로 나타나 재배 기간이 늘수록 자긍심이 커지는 것으로 조사되었다. 한국 춘란재배에 따른 자신감, 행복감, 만족감 관련 문항을 종속변수로 하고 자긍심 척도를 통해 얻은 검사 문항을 독립변수로 하는 회귀분석의 결과, 회귀 모형의 p값이 모두 0.00(>0.01)으로 나타나 자긍심은 춘란재배를 통해서 얻어지는 자신감, 행복감, 만족감에 의해 증가됨을 알 수 있었다.
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