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        검색결과 82

        41.
        2018.04 서비스 종료(열람 제한)
        Recently, concrete-steel hybrid girder is being developed to improve economic efficiency and durability. To evaluate flexural behavior of the proposed girders, 17.0m full-scale joint was fabricated and tested under vertical loading. The study was examined vertical displacement; the strain of the reinforcement; and the crack patterns in the concrete. The proposed girders was analyzed to be safe in all members.
        42.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        Background: An imbalance in energy intake and expenditure can cause obesity, which is a major risk factor for chronic diseases such as heart disease, type 2 diabetes, insulin resistance, cancers and hyperlipidemia. Methods and Results: In this study, we evaluated the anti-obesity effects of a water extract from the young leaves of barley sprout (BS) in 3T3-L1 cells and in high-fat diet (HFD)-induced obese mice (HF). Lipid accumulation measurement indicates that BS markedly inhibited adipogenesis by reducing lipid droplet production in a dose-dependent manner. Furthermore, the mRNA expression of adipogenic transcription factors peroxisome proliferator-activated receptor-γ and fatty acid synthetase, CCAAT/enhancer binding protein-α and fatty acid binding protein 4 in 3T3-L1 cells was significantly inhibited by BS treatment. In an in vivo test, the BSadministered group of HFD-induced mice showed less body weight gain, and lower liver and epididymal white adipose tissue weights. The BS-treated mice showed decreased serum levels of leptin and lipids compared to untreated HFD mice and the levels of adiponectin and the HDL-cholesterol/total cholesterol ratio increased. These results indicate that BS inhibits body fat accumulation by reducing the mRNA expression of lipogenesis transcription factors and increasing serum adipokine concentration in in vitro and in vivo tests. Conclusions: BS reduced high fat diet-induced weight gain and had a positive effect on dyslipidemia.
        43.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        탄소나노튜브는 고강도, 고내구성 콘크리트의 생산을 위한 새로운 재료 중 하나로 여겨지며, 많은 연구자들에 의하여 연구되고 있 다. 탁월한 열전도도는 향후 자가발열 콘크리트의 개발에 필수적이며, 이 연구에서는 다양한 목적을 갖는 콘크리트의 개발을 위한 역학적 특성 및 미세구조 분석을 실시하였다. CNT 첨가량은 시멘트 중량대비 0.115, 0.23, 0.46wt%로 하였다. 압축강도/휨강도 시험은 재령 3, 7, 28일에 실 시하였으며, 공극률은 MIP 시험을 통해 실시하였다. CNT 분산성 및 수화생성물 분석을 위하여, SEM 분석 및 열분석을 실시하였다. 그 결과, CNT 첨가에 따른 역학성능은 다소 감소하는 경향을 나타내었으나, 0.115wt% 첨가한 경우 플레인 배합과 동등 수준의 결과를 확인할 수 있었 다. 향후, 기존 콘크리트와 동일한 역학성능을 보유한 CNT 첨가 배합의 개발을 통한 발열성능 확보가 가능할 것으로 기대된다.
        44.
        2017.04 서비스 종료(열람 제한)
        Traditional marine structures are difficult to construct under the marine environment. These structure have maintenance costs associated with the chloride attack environments. In this paper, a new structure system is proposed to overcome these disadvantages. The connection of precast reinforced concrete girders and bent cap is the main feature of the proposed structure system. To assess the joint performance of the proposed methods, full-scale joint was fabricated and tested under cyclic loading. The key parameters examined were the pile displacement; the strain in the reinforcement; and the crack patterns in the concrete. The test structure behaved stably for cyclic loading. The test structure is analyzed to be safe in all members.
        45.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        Traditional marine structures are difficult to construct under the marine environment. These structure have maintenance costs associated with the chloride attack environments. In this paper, a new structure system is proposed to overcome these disadvantages. The connection of precast reinforced concrete girders and bent cap is the main feature of the proposed structure system. To assess the joint performance of the proposed methods, full-scale joint was fabricated and tested under cyclic loading. The key parameters examined were the pile displacement; the strain in the reinforcement; and the crack patterns in the concrete. The test structure behaved stably for cyclic loading. The test structure is analyzed to be safe in all members.
        46.
        2016.10 서비스 종료(열람 제한)
        Background : Korean Indigenous Hylotelephium erythrostictum is widely distributed in South Korea and is used in Korean traditional medicine. In this study, the phylogenetic analysis of Korean native Hylotelephium erythrostictum and related plants on Internal Transcribed Spacer (ITS) sequences were investigated to distinguish its origin. Methods and Results : The phylogenetic analysis of 6 species of Hylotelephium were investigated by ITS. The dendrogram was constructed by UPGMA(Unweighted Pair Group Method with Arithmetic Mean) clustering algorithm based on genetic similarity of ITS. In the ITS sequence analysis, the size of total was varied from 676 to 779 bp. The size of ITS 1 was rated at 287bp, while ITS 2 was rated at 123bp. The G+C content of ITS region was ranged from 60 to 66%. In the ITS tree, six species of Hylotelephium were monophyletic, and H. viviparum was the first branching within the clade. Conclusion : H. spectabile formed a clade with H. erythrostictum, while H. verticillatum formed with H. viviparum.
        47.
        2016.06 KCI 등재 서비스 종료(열람 제한)
        Background: Sedum takesimense Nakai has been used as folk medicine in Korea. The present study aimed to determine the biological activity of S. takesimense by investigating the anti-inflammatory effects of S. takesimense water extract (SKLC) on the lipopolysaccharide-induced inflammatory response in RAW 264.7 cells. Methods and Results: Cytotoxicity of SKLC on RAW 264.7 cells was determinded by performing MTS assay was found to have no cytotoxic effect on RAW 264.7 cells at a concentration range of 62 - 500 ㎍/㎖. Further, pretreatment of SKLC inhibited lipopolysaccharide-induced nitric oxide (NO) production in a dose-dependent manner. To determined the inhibitory mechanisms of SKLC on inflammatory mediators, we assessed the inducible nitric oxide synthase (iNOS) and cyclooxygnease-2 (COX-2) pathways. The activities of these pathways were decreased in a dose-dependent manner by SKLC. The production of tumor necrosis factor- α (TNF-α), interleukin (IL)-1β‚ and IL-6 were also reduced. Conclusions: These results suggest that the down regulation of iNOS, COX-2, TNF-α, IL-1β‚ and IL-6 expression by SKLC are mediated by the down regulation of nuclear factor-κB (NF-κB) activity, a transcription factor necessary for pro-inflammatory mediators. This might be the mechanism underlying the anti-inflammatory effects of SKLC.
        48.
        2016.04 KCI 등재 서비스 종료(열람 제한)
        Melanin is produced by melanocytes of the melanoepidermic unit and other cell types. These cells secrete and distribute the melanin pigment, which provides protection from ultraviolet radiation. In this study, the inhibitory activity against tyrosinase and melanin biosynthesis in B16F10 melanoma cells and anti-wrinkling effects on human dermal fibroblasts of Dendrobium speciosum ethanol extract were investigated. The Dendrobium speciosum extract inhibited melanin biosynthesis and tyrosinase activity in a dose-dependent manner in comparison with an untreated control group. Treatment with the Dendrobium speciosum extract suppressed α-MSH-stimulated melanogenesis in B16F10 cells and the dendrite outgrowth of melanocyte/melanoma cells. The α-MSH-induced mRNA expression of tyrosinase-related protein-1 (TRP-1), tyrosinase-related protein-2 (TRP-2) and microphthalmia-associated transcription factor (MITF) was significantly attenuated in a concentration-dependent manner by Dendrobium speciosum treatment. In addition, Dendrobium speciosum treatment increased production of type I procollagen synthesis in human dermal fibroblasts. Dendrobium speciosum ethanol extract exhibited a potent inhibitory effect on melanin biosynthesis, tyrosinase activity and increased procollagen synthesis. These results indicate that Dendrobium speciosum shows promise as an ingredient in cosmeceutical products due to its whitening and anti-wrinkle effects.
        49.
        2016.04 서비스 종료(열람 제한)
        Recently, a Multi-Walled Carbon Nano Tube(MWCNT) is widely used to increase mechanical strength of the cementitious composite material. In this study, a dilution of MWCNT aqueous solution(from wt 2.0%, 1.5% to wt 1.0%) is a main parameter. A compressive strength of diluted CNT cement mortar is maximum 4.7% larger than that of a pure CNT cement mortar. The result indicates that the diluted MWCNT aqueous solution of the MWCNT cement mortar makes very little differences of the compressive strength.
        50.
        2016.04 서비스 종료(열람 제한)
        This study investigated the behavior of newly-developed circular steel girder over bridge. The traditional bridge is a simple span with the maximum span length about 7.0m. The proposed bridge is sequenced by extending a steel tube girder and reducing the number of infrastructure. It can make to improve constructability and save cost. In this study, we conducted a finite element analysis of the behavior of the main part, and aimed to check the compliance of allowable stress.
        51.
        2016.02 KCI 등재 서비스 종료(열람 제한)
        Background : The white jelly mushroom (Tremella fuciformis), one of the most popular edible fungi, has medicinal properties. However, the effects of T. fuciformis in skin whitening or anti-wrinkle efficacy has not been defined to date. The aim of the present study was to investigate the effects of T. fuciformis extracts on whitening and anti-wrinkle efficacy in skin cells. Methods and Results :We prepared T. fuciformis extracts with water. The extracts (80℃) contained 12.11 ㎎/g polyphenol and 8.54 ㎎/g flavonoid concentration. T. fuciformis extracts markedly decreased melanin contents and tyrosinase activity in α-MSHstimulated melanocytes (B16F10 cells). In addition, the mRNA expression of melanin formation factors, such as microphthalmiaassociated transcription factor (MITF), tyrosinase-related protein-1 (TRP-1) and tyrosinase-related protein-2 (TRP-2) were significantly down-regulated in α-MSH-stimulated melanocyte. Furthermore, T. fuciformis extracts increased the synthesis of type I procollagen and reduced mRNA expression of matrix metalloproteinase 1 (MMP-1) in the human dermal fibroblast (HDFn cells). These data indicated that T. fuciformis extracts induce repression of cellular melanogenesis and protect against wrinkles caused by UVB-stimulated damage. Conclusions : Thus T. fuciformis extracts could be a cosmetic candidate for skin whitening and anti-wrinkle effects.
        52.
        2016.02 KCI 등재 서비스 종료(열람 제한)
        Background : Irregular meals and insufficient exercise are major modern lifestyle-related risk factors for constipation. This study aimed to examine the effects of the aqueous extract of Dendrobium speciosum var. (DM) on the improvement of intestinal function and prevention of constipation in rats. Methods and Results : Constipation in rat was induced by loperamide (4 ㎎/㎏) injection for 5 days and rats were randomly assigned to the following groups: normal control rats (NOR), constipated rats (LOP induced) and constipated rats supplemented with dulcolax-S (POS), DMSG, 100 ㎎/㎏ (DMSG-100), 300 ㎎/㎏ (DMSG-300) and 500 ㎎/㎏ (DMSG-500). The DMSG groups showed increments in the frequency and amount of stools compared to the LOP group. Loperamide treatment markedly reduced the water content of feces, whereas DMSG administration significantly increased fecal water contents. Moreover, DMSG improved intestinal transit speed in constipated-rats. Alcian blue staining revealed increased mucus production by crypt cells and mucus contents in feces and the mucosal surface. Conclusions : In summary, DM extraction significantly improves intestinal function in rats, which indicates the effectiveness of this extract in the prevention and treatment of constipation.
        53.
        2016.02 KCI 등재 서비스 종료(열람 제한)
        Obesity is a pro-inflammatory state that contributes to the development of metabolic disorders such as hyperlipidemia, insulin resistance, type 2 diabetes, non-alcoholic fatty liver, and cardiovascular disease. In this study, we evaluated the inhibition of adipogenesis in 3T3-L1 cells and in high-fat diet (HFD)-induced obese mice by Peucedanum japonicum Thunberg L. water extract (PJT). Lipid accumulation measurement indicates that PJT markedly inhibited adipogenesis in a dose-dependent manner. RT-PCR results demonstrated that the mRNA expression of adipogenic transcription factors such as peroxisome proliferator-activated receptor-γ (PPARγ) and CCAAT/enhancer binding protein- α (C/EBPα) in 3T3-L1 cells were significantly down-regulated by PJT treatment. Oral administration of PJT (100, 300, and 500 ㎎/㎏, b.w/daily for 4 weeks) was conducted in high-fat diet induced obese mice and C57BL/6 mice. The PJT-administered group of HFD-induced mice had a lower body weight gain, along with decreased serum levels of glucose, triglycerides, and total cholesterol compared with the control mice, however, the HDL-cholesterol/total cholesterol ratio was increased. Furthermore, the elevated mRNA expression levels of adipogenesis related genes in the white adipose tissue of obese mice were significantly suppressed by PJT. These results indicate that PJT exhibits anti-obesity effects in obese mice by decreasing in serum lipid levels and lipogenesis related gene.
        54.
        2016.01 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 비용예측모델과 성능예측모델을 이용하여 네트워크 레벨에서 향후 교량과 터널 유지관리 비용과 성능을 예측할 수 있는 방법론은 개발하였다. 현재 국내의 시설물 유지관리 관련 연구는 대부분 단일 시설물에 집중되어 있어 도로망차원의 네트워크 레벨 분석 에는 적용하기 어렵다. 따라서 시설물군 단위로 유지관리 계획을 수립해야하는 실무주체에게 유의한 정보를 제공하지 못하고 있는 실정이다. 본 연구의 예측모델은 시설물의 성능에 현재 시특법에 의해 평가하고 있는 상태외 사용성과 기능성을 포함하였으며, 기본 분석과 확장 분석을 통해 각 시설물의 조치 시기와 연간 예산을 추정할 수 있다. 또한 사례 분석을 통해 기술적 타당성을 검증하였다. 본 연구의 방법론이 활성화된 다면 다수의 시설물의 비용대비 미래 성능을 파악할 수 있으며, 효과적인 중장기 예산 수립을 할 수 있을 것으로 판단된다.
        55.
        2015.08 KCI 등재 서비스 종료(열람 제한)
        Dendrobium loddigesii (DL) is a valuable and versatile herbal medicine with the anecdotal claims of anti-oxidant and anti-inflammation. In the present study, we investigated the whitening effects of DL under various conditions with B16F10 melanoma cells. The DL extract inhibited melanin contents and tyrosinase activity in a dose-dependent manner, compared with untreated group. Treatment of the DL extract effectively suppressed the α-MSH-stimulated melanin formation, tyrosinase activity and dendrite outgrowth. Moreover, the α-MSH-induced mRNA expressions of tyrosinase-related protein-1 (TRP-1), tyrosinase-related protein-2 (TRP-2), microphthalmia-associated transcription factor (MITF) and protein expression of tyrosinase were significantly attenuated by DL treatment. These results indicate that DL may be a great cosmeceutical ingredient for its whitening effects.
        57.
        2015.04 서비스 종료(열람 제한)
        Recently there are many study on the effect of improving the compressive strength of MWCNT-cement composites. However study related to MWCNT-cement yet insignificant to the domestic. The MWCNT have excellent mechanical characteristics which are mixing cement. MWCNT-cement composites can be expected improving compressive strength. This parametric experimental study have verified to increasing compressive strength of mortar composites mixing MWCNT as W/C, curing age.
        58.
        2015.04 서비스 종료(열람 제한)
        The Goal of research is that decision-making in bridge and tunnel maintenance were estimated by prediction models of condition and value engineering. We developed the software that can be calculated asset values and it’s condition depending on budget scenario by the bridge and tunnel prediction model. It can be determined an optimal budget of facilities and it’s values using prediction model of cost and condition.
        59.
        2015.04 서비스 종료(열람 제한)
        It is necessary to introduce a Reoprt Card that utilized in the developed countries for improved aging domestic Infrastructure. To do that, by improving to match the domestic environment, it is necessary to make a reliable accurate evaluation. Korean evaluation grade is, in consideration of both the life cycle of Infrastructure, should comprehensively evaluated by physical and environmental and social point of view is made .
        60.
        2015.02 서비스 종료(열람 제한)
        본 연구는 제방 시설물에 대한 사용자 관점에서의 성능 평가에 관한 논문이다. 현재 국내의 제방 시설물은 평균 내구수명이 30년이 경과하여 매우 노후된 실정이며, 1, 2종을 제외한 기타 시설물의 경우는 정확한 현황 파악이 어렵고 거의 방치되고 있는 실정이다. 매년 장마 및 태풍 발생 시 제방의 붕괴로 인해 많은 재산 및 인명 피해가 발생하고 있어 이에 대한 대처가 필요한 실정이나, 제방에 대한 종합적인 평가 기준이 전무한 실정이다. 현재 안전진단지침에 따른 기존 제방 시설물 평가의 경우 상태와 제방 붕괴 관점에서 등급을 평가하며, 복합한 과정을 거치기 때문에 모든 시설물 평가에 적용하기 어렵다. 또한, 보다 합리적인 평가를 위해서는 제방의 붕괴되었을 경우의 피해 농경지, 기후 조건, 통행 여건, 인접 가구수, 관광지 접근성 등 사용자 입장에서 보다 다양한 평가지표가 필요하다. 본 연구에서는 피해정도, 환경, 사용자 편의 관점에서의 제방 시설물의 성능을 평가할 수 있는 새로운 지표를 개발하여 제방의 성능을 합리적으로 평가할 수 있는 등급을 제시하고자 한다. 이를 통해 취약한 시설물에 예산 배정이 우선적으로 이루어질 수 있다면 이용자 안전성 확보, 투자효과 극대화, 지역 경제 활성화 등 많은 기대효과를 얻을 수 있을 것으로 예상된다.
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