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        검색결과 6

        1.
        2018.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 콕스회귀분석과 누적한계추정법으로 1995년부터 2015년까지 1,084개의 국내 소프트웨어 기업을 분석하고, 생존율과 생존의 결정요인을 밝히는 것이다. 분석 결과 생존율의 경우, IT서비스, 패키지 소프트웨어, 게임 소프트웨어, 인터넷 서비스 각 분야별로 다른 형태를 보였다. 또한 연구개발 투자와 기업의 매출액 및 자산증가율로 나타나는 성장성은 생존에 긍정적이었으며, 여유자원은 부정적인 영향을 미쳤으며, 나이와 규모는 그 영향을 찾을 수 없었다. 이러한 결과는 소프트웨어 기업의 생존 전략과 정부의 지원 정책에 있어서 산업과 기술의 특성을 고려해야 한다는 점을 시사한다. 본 연구는 90년대 말 외환위기라는 특수 상황이나 제조업 중심으로 진행된 국내 생존분석의 영역을 최근 중요성이 커지는 소프트웨어 산업으로 확장했다는 의미가 있다.
        6,100원
        2.
        2017.02 KCI 등재 서비스 종료(열람 제한)
        Background: Ganoderma lucidum cultured on hulled barley was investigated as a potential natural source of antioxidants and antiinflammatory agents. Methods and Results: The yields from Ganoderma lucidum cultured on hulled barley water and ethanol extract were 17.69% and 25.77%, respectively. The antioxidant activity of Ganoderma lucidum cultured on hulled barley extracts was confirmed by various methods including assayss of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethylbenzo thiazoline-6-sulfonic acid) (ABTS), nitrite radical scavenging, and Fe3+ to Fe2+ reducing power activity. The ethanol extract of Ganoderma lucidum cultured on hulled barley showed improved DPPH, ABTS and nitrite radical scavenging activity compared with the water extract. After treatment of RAW264.7 cells with Ganoderma lucidum cultured on hulled barley ethanol extracts, the cell viability compared with the control was 92.82%, even at a concentration of 3,000 ㎍/㎖. The ethanol extract inhibited reactive oxygen species (ROS) generation in RAW264.7 cells stimulated with H2O2, even at low concentrations. In addition, the ethanol extract showed an inhibitory effects on the production of lipopolysaccharide-induced nitric oxide (NO) in RAW264.7 cells. Conclusions: This study suggests that the extract of Ganoderma lucidum cultured on hulled barley is a potential source of natural antioxidants and anti-inflammatory agents.
        3.
        2016.10 서비스 종료(열람 제한)
        Background : Lactuca sativa (LS) is a member of lactuca genus and the Asteraceae family. To its usual purpose as an edible leafy vegetable, lettuce has had a number of uses in ancient times as a medicinal herb. Depending on the variety, lettuce is an excellent source vitamin K and vitanin A. Methods and Results : The objective of this study is to find out the antioxidant and oxidative DNA damage prevention capacity of LS for both water and ethanol extract. The total phenolic and flavonoid contents have been estimated in this study. The extracts have been tested to assess the 1, 1-diphenyl-2-picryl-hydrazyl (DPPH), 2,2ʹ -azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and nitrite scavenging activity. We have also evaluated the reducing power activity of LS. LS extracts showed a good radical scavenging activity on DPPH and ABTS free radical as concentration dependent manner. The IC50 values on DPPH radical scavenging activity were 0.75 mg/mL and 0.54 mg/mL for water and ethanol extract respectively. ABTS radical scavenging activity ranges from 38-89 % for water extract and 33-96% for ethanol extract. Although ethanolic extract showed a higher radical scavenging activity as compared to the water extracts. All the extracts exhibited reducing power activity, dose dependently. Moreover, when the DNA was treated with the extracts, supercoiled DNA was restored in a concentration-dependent manner. Conclusion : According to the results, we suggest that LS contains considerable amount of phenolic and flavonoid content and could be used as a source of natural antioxidant substances and oxidative DNA damage preventer.
        4.
        2016.10 서비스 종료(열람 제한)
        Background : Achyranthes japonica Nakai (AJ) is a perennial herb with a wide distribution in East Asia including Korea, China, and Japan, and it is mainly used as a medicinal plant. In Korea, AJ has been widely used to control pain and improve symptoms in OA patients. AJ contains several important phytochemicals such as saponins, inokosterone, ecdysterone, and oleanolic acid bisdesmoside. Methods and Results : The aim of this work was to investigate the antioxidant and anti-inflammatory activities of fermented and ethanol extracts of Achyranthes japonica Nakai (AJ). The extracts showed strong reductive power and nitrite scavenging, hydroxyl radical scavenging, superoxide radical scavenging, and DNA damage prevention activities. Treatment of RAW 264.7 macrophages with AJ inhibited lipopolysaccharide (LPS)-induced NO secretion and iNOS expression without affecting cell viability. AJ also inhibited cyclooxygenase 2 (COX-2) expression, leading to the suppression of COX-2-derived prostaglandin E2 production. These inhibitory effects of AJ were accompanied by reduced production of tumor necrosis factor-α and interleukins (IL)-1β, -6, and -10. Furthermore, AJ suppressed LPS-induced phosphorylation of extracellular signal regulated kinase, c-Jun N-terminal kinase, and p38. Moreover, AJ inhibited malondialdehyde production and myeloperoxidase activity in LPS-stimulated RAW 264.7 cells. Conclusion : The antioxidant activity of plants is closely related to their medicinal properties and is widely used as a parameter to determine the bioavailability of medicinal plants. The antioxidant and biological activities of AJ extracts might be due to the synergistic actions of multiple bioactive compounds. It can be concluded that AJ extracts are a potential source of biologically important drug candidates.
        5.
        2016.10 서비스 종료(열람 제한)
        Background : ROS produced by oxidative stress damaged endothelial cells, and cause a variety of vascular complications. In diabetic hyperglycemia state, ROS increase. The polyol pathway occur in diabetic complications, the excess glucose is absorbed into the polyol pathway when aldose reductase increased, NADPH changes it to sorbitol. Glutathione (GSH) removes ROS. GSH level is reduced by glutathione reductase, using NADPH as an electron donor. Activation of the polyol pathway decrease NADPH, and GSH also reduced. As a result, ROS is increased. In diabetic hyperglycemia state, Glycolysis increases. Effects of increased glycolysis, protein kinase C (PKC) is increased. NAD(P)H oxidase, stimulated by PKC-dependent pathway, increases ROS in the cell. In this study, we measured the ROS scavenging activity of 5 natural products (Lycii fructus, Astragalus membranaceus, Cassia Tora, Polygonatum odoratum, Rubus Coreanus), to confirm the efficacy as diabetic antioxidants. Methods and Results : We extracted 5 natural product by distilled water and ethanol. DPPH radical scavenging activity was significantly higher in Lycii fructus, Rubus coreanus. ABTS radical scavenging activity was better Rubus coreanus, Lycii fructus, Cassia Tora. In addition to, Rubus coreanus, Cassia Tora, Lycii fructus was comparatively higher reducing power activity than other natural products. And total phenolic and flavonoid contents were much higher in Rubus coreanus compared with other extracts. Conclusion : These results suggest that Lycii fructus, Rubus coreanus can be applied as diabetic antioxidant that prevent vascular complications caused by ROS.