• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.775-783
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• 2010

새마을 동차를 유지보수하는 용산기지의 이전에 따른 새마을 동차를 유지보수 할 기지가 없어, 현재 내구연한 20년인 새마을동차의 조기폐차가 논의 되고 있지만, 철도차량의 도입에 많은 비용이 소요되고, 정확한 정책판단이 요청되어 경제성 분석을 시행하였다. 분석을 위해 기존의 PP동차를 조기 폐차하는 경우와 신규간선형 EMU를 도입하는 경우, 철도차량정밀진단을 통해 PP동차를 내구연한을 초과하여 사용하는 경우를 시나리오 설정을 통해서 경제성분석을 시도하였다. 경제성 분석을 위해서 크게 유지보수비, 운영비, 차량감가상각비(차량 잔존가액)와 조기폐차에 따른 부대적인 비용을 산정하여 분석하였다. 특정한 철도공사의 사례이지만, 디젤차량과 전기차량의 운영비적인 측면에서 상세한 검토자료가 될 수 있다.

• Journal of Acupuncture Research
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• 제22권2호
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• pp.203-210
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• 2005

Objectives : The purpose of this study was to investigate anti-cancer effects of various ginseng herbal acupuncture in mice and expression of cytokine mRNA. Methods: Anti-cancer effects of various ginseng herbal acupuncture were tested by measuring the increase of life span of mice suffering from peritoneal cancer induced by Sarcoma-180, and expression of mRNA manifestation using RT-PCR. The results are as follows: Results: 1. Increase of life span of mice suffering from peritoneal cancer induced by Sarcoma-180 was measured for anti-cancer effects. As a result, 115% increase was shown in the cultivated wild ginseng group, 11.1% increase in the red ginseng group, and no increase was detected in either white ginseng and fresh ginseng groups. 2. Measuring the expression of cytokine mRNA manifestation, expression of $interferon-{\gamma}$ was slightly increased in the cultivated wild ginseng group compared to the control group, but manifestation of interleukin-10 was slightly decreased. 3. For the red ginseng, white ginseng, and fresh ginseng experiment groups II, IL-2, IL-4, $INF-{\gamma}$, and IL -10 all showed increase suggesting possible error occurring during the test process. Conclusion: From the results obtained in this study, we can reason that the ginseng we use may not match the ginseng cited in the texts of the past. Anti-cancer effects of cultivated wild ginseng can be more potent than those of white and fresh ginseng.

• 예술인문사회 융합 멀티미디어 논문지
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• 제8권7호
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• pp.475-484
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• 2018

전기철도차량의 추진제어장치는 자동차의 엔진에 해당되는 핵심 주요부품이며 이를 제어하는 장치는 GDU(Gate Drive Unit)라는 장치를 이용한다. 또한, 추진제어장치의 고장 빈도를 파악해보면 GDU에 대한 부적합 비율이 가장 높았다. GDU는 외국산 도입으로 인하여 핵심기술의 접근이 불가하였고, 제작사의 GDU 단종으로 전반적인 유지보수 활동에 전반적인 문제점이 있었다. GDU는 최장 23년부터 최근 14년의 장기간 사용으로 수명이 도래하였다. 본 연구는 이러한 문제점을 해결하고자 호환이 가능한 GDU의 확보와 고장을 분석하여 적정수명을 파악하기 위한 것으로, 기존의 상태검사 위주의 유지보수 방법 개선을 위해 설계를 변경하여 추진제어장치의 GDU를 커패시터 교환 형으로 개발하였다. 전체수명에 비해 비교적 수명이 짧은 구성부품의 유지보수는 필수이며, 대부분의 건설초기의 최초 외산도입 부품은 기술종속 및 장기운영의 결과로 관련 부품의 단종이 발생하면 고장발생 시 수급불가 등으로 기본적인 교환에 대한 유지보수에 문제점이 발생되고 있으나, 25년 이상으로 전체수명이 긴 철도차량의 특성상 앞으로도 상당기간 운영이 필요하여 개조 혹은 대체품 개발로 부품확보 및 일정수준의 품질을 유지할 필요가 강조되며, 이에 대한 연구는 보다 구체적이고 실증적으로 이루어져야 한다. 커패시터 교환 형 GDU는 커패시터 모듈의 분리를 통해 정전용량을 쉽게 측정하여 수명을 판단하고, 단품 시험과 커패시터의 수명을 측정하여 정확한 예방유지보수를 할 수 있어서 운행 중 열차의 부적합을 미리 예방할 수 있으며, 24개월 이상의 영업 운전을 통하여 한건의 부적합 없이 영업운행에 성공하여 기존품의 대체 가능여부를 검증하였다.

• Steel and Composite Structures
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• 제23권4호
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• pp.435-444
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• 2017

In the past, the progressive collapse resulting from local failures during accidents has caused many tragedies and loss of life. Although long-span spatial grid structures are characterised by a high degree of static indeterminacy, the sudden failure of key members may lead to a catastrophic progressive collapse. For this reason, it is especially necessary to research the progressive collapse resistance capacity of long-span spatial grid structures. This paper presents an evaluation method of important members and a novel dynamic analysis method for simulating the progressive collapse of long-span spatial grid structures. Engineering cases were analysed to validate these proposed method. These proposed methods were eventually implemented in the progressive collapse analysis of the main stadium for the Universiade Sports Center. The roof of the structure was concluded to have good resistance against progressive collapse. The novel methods provide results close to practice and are especially suitable for the progressive collapse analysis of long-span spatial grid structures.

• Molecules and Cells
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• 제38권12호
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• pp.1054-1063
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• 2015

Mitochondria play a crucial role in eukaryotic cells; the mitochondrial electron transport chain (ETC) generates adenosine triphosphate (ATP), which serves as an energy source for numerous critical cellular activities. However, the ETC also generates deleterious reactive oxygen species (ROS) as a natural byproduct of oxidative phosphorylation. ROS are considered the major cause of aging because they damage proteins, lipids, and DNA by oxidation. We analyzed the chronological life span, growth phenotype, mitochondrial membrane potential (MMP), and intracellular ATP and mitochondrial superoxide levels of 33 single ETC component-deleted strains during the chronological aging process. Among the ETC mutant strains, 14 ($sdh1{\Delta}$, $sdh2{\Delta}$, $sdh4{\Delta}$, $cor1{\Delta}$, $cyt1{\Delta}$, $qcr7{\Delta}$, $qcr8{\Delta}$, $rip1{\Delta}$, $cox6{\Delta}$, $cox7{\Delta}$, $cox9{\Delta}$, $atp4{\Delta}$, $atp7{\Delta}$, and $atp17{\Delta}$) showed a significantly shorter life span. The deleted genes encode important elements of the ETC components succinate dehydrogenase (complex II) and cytochrome c oxidase (complex IV), and some of the deletions lead to structural instability of the membrane-$F_1F_0$-ATP synthase due to mutations in the stator stalk (complex V). These short-lived strains generated higher superoxide levels and produced lower ATP levels without alteration of MMP. In summary, ETC mutations decreased the life span of yeast due to impaired mitochondrial efficiency.

• 한국사회복지학
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• 제58권1호
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• pp.237-264
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• 2006

최근 장애 정의에 있어 환경적인 요인이 중요한 비중을 차지하게 됨에 따라 새로운 패러다임에 근거 한 사회통합 논의의 필요성이 대두하게 되었다. 한편 장애문제를 비장애인과 마찬가지로 장애의 경험에 국한되지 않고 총체적인 삶의 경험에 초점을 맞추어야 한다는 생애주기별 접근의 중요성이 강조되고 있다. 본 연구의 목적은 생애주기별로 자립생활 패러다임에 따른 사회통합 수준을 측정하고 영향요인에 대해 분석함으로써 질적 측면에서 정책적, 실천적 함의를 제공하는 데 있다. 자립생활 패러다임에 따른 사회통합의 하위차원은 일상생활 자율성, 물리적 접근성, 사회적 지지의 적절성, 경제적 안정정도, 선택권, 심리적 임파워먼트의 6개 차원으로 구분하였다. 조사대상자는 서울과 경기지역에 거주하는 지체 및 뇌병변장애인 591명이며, 전화설문조사방법을 사용하였다. 연구결과 생애주기별로 사회통합의 하위차원에 따라 다른 특성을 보였고 사회통합의 각 차원별로 영향을 미치는 요인이 상이하게 나타났다. 이러한 결과를 통해 얻을 수 있는 중요한 함의는 사회통합의 증진을 위한 장애정책의 방향은 생애주기별로 차별화 되어야 하며 장애인의 일상 활동이나 접근성의 향상뿐만 아니라 선택권이나 심리적 임파워먼트의 증진을 위한 노력이 병행될 필요가 있다는 것이다.

• Nutrition Research and Practice
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• 제1권2호
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• pp.105-112
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• 2007

Ascorbic acid has been reported to extend replicative life span of human embryonic fibroblast (HEF). Since the detailed molecular mechanism of this phenomenon has not been investigated, we attempted to elucidate. Continuous treatment of HEF cells with ascorbic acid at ($200{\mu}M$) from 40 population doubling (PD) increased maximum PD numbers by 18% and lowered $SA-{\beta}-gal$ positive staining, an aging marker, by 2.3 folds, indicating that ascorbic acid extends replicative life span of HEF cells. Ascorbic acid treatment lowered DCFH by about 7 folds and Rho123 by about 70%, suggesting that ascorbic acid dramatically decreased ROS formation. Ascorbic acid also increased aconitase activity, a marker of mitochondrial aging, by 41%, indicating that ascorbic acid treatment restores age-related decline of mitochondrial function. Cell cycle analysis by flow cytometry revealed that ascorbic acid treatment decreased G1 population up to 12%. Further western blot analysis showed that ascorbic acid treatment decreased levels of p53, phospho-p53 at ser 15, and p21, indicating that ascorbic acid relieved senescence-related G1 arrest. Analysis of AP (apurinic/apyrimidinic) sites showed that ascorbic acid treatment decreased AP site formation by 35%. We also tested the effect of hydrogen peroxide treatment, as an additional oxidative stress. Continuous treatment of $20{\mu}M$ of hydrogen peroxide from PD 40 of HEF cells resulted in premature senescence due to increased ROS level, and increased AP sites. Taken together, the results suggest that ascorbic acid extends replicative life span of HEF cells by reducing mitochondrial and DNA damages through lowering cellular ROS.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1074-1079
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• 2007

It is important to evaluate the effect in the maintenance of steel bridge because the fatigue of the bridge is affected by the structural characteristic of bridge such as structure type, span and steel grade, etc. In this study, we analyzed the effect of fatigue strength by the changes of span of the bridge and the steel grade in many factors which have influence on the fatigue life of the bridge. For this analysis, we selected the objective bridges and performed the structural analyses for the various parameters such as span and steel grade. The fatigue evaluations were carried out by FAST which is a program for fatigue estimation and the results were compared.

• International Journal of Industrial Entomology and Biomaterials
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• 제12권1호
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• pp.1-5
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• 2006

Cordyceps, one of the well-known traditional Chinese medicines, consists of the dried fungus C. sinensis growing on the larva of caterpillar. It is commonly used as a tonic of restoring vital body functions. In order to evaluate the pharmacological effects of C. militaris, the anti-oxidation and antiaging effect of cultured C. militaris growing on pupa of silkworm Bombyx mori, were investigated. The results showed! that the contents of lipofusin in myocardium were reduced and the SOD activity in the liver were elevated in a dose-dependent manner while no effect was observed for blood GSH-Px activity and liver MDA content in mice perfused with the cultured C. militaris compared to those untreated mice. Furthermore, the average life span, maximum life span and 50% death time of the fruit flies treated with cultured C. militaris were markedly prolonged. The results suggest that the cultured C. militaris growing on pupa of silkworm possesses anti-oxidation and delay senescence activity.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.249-256
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• 1999

This study is intended to propose a systematic procedure for the development of the reliability-based seismic safety and cost-effective Performance criteria for design and upgrading of long span PC bridges. In the paper, a set of cost function models for life cycle cost analysis of bridges is proposed. The total life cycle cost functions consist of initial cost and direct/indirect damage costs considering repair/replacement costs, human losses and property damage costs, road user costs, and indirect regional economic losses. The damage costs are successfully expressed in terms of Park-Ang median global damage indices and damage probabilities. The proposed approach is successfully applied to model bridges in both regions of a moderate seismicity area like Seoul, Korea and a high one like Tokyo, Japan. It may be expected that the proposed approach can be effectively utilized for the development of cost-effective performance criteria for design and upgrading of various types of bridges as well as long span PC bridges.