• Biomolecules & Therapeutics
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• 제9권3호
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• pp.167-175
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• 2001

Recent studies have shown that cytokines are capable of modulating cardiovascular function and that some drugs used in the treatment of heart failure variably modulate the production of cytokines. Hige- namine, a positive inotropic isoquinoline alkaloid, has been used traditionally as cardiac stimulant, and reported to reduce nitric oxide (NO) and inducible nitric oxide synthase (iNOS) expression in LPS- and/or cytokine-activated cells in vitro and in vivo. Therefore, we investigated whether higenamine modulates the production of proinflammatory cytokines in myocardial infarction. In addition, effects of higenamine on antioxidant action and antioxidant enzyme expression (MnSOD) were studied. Myocardial infarction (MI) was confirmed by measuring left ventricular (LV) pressure after occlusion of the left anterior descending coronary artery (LAD) for 5 weeks in rats. Treatment of higenamine (10 mg/kg/day) reduced infarct size about 35 %, which accompanied by reduction of production TNF-$\alpha$, IL-6, but not IFN-${\gamma}$ and IL-1$\beta$ in the myocardium. The expression of TNF-$\alpha$ mRNA in infracted myocardium was significantly reduced by higenamine. Although iNOS mRNA was not detected, nitrotyrosine staining was significantly increased in myocardium of Ml compared to higenamine-treated one, Indicating that peroxynitrite-induced damage is evident in MI. Cytochrome c oxidation by peroxynitrite was concentration-dependently reduced by higenamine, an effect which was almost compatible to glutathion. Higenamine treatment did not affect the expression of MnSOD mRNA in myocardial tissues in MI. Taken together, higenamine may be beneficial in oxidative stress conditions such as ischemic-reperfusion injury and MI due to antioxidant action as well as modulation of cytokines.

• 생명과학회지
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• 제30권8호
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• pp.661-671
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• 2020

항암 요법의 실패의 주요 원인으로 암세포의 항암제에 대한 내성 획득이 잘 알려져 있다. 비스테로이드소염제(NSAID)는 항염증작용뿐만 아니라 항암제와의 병용요법으로 임상적인 암 치료 요법에 응용되고있다. 본 연구에서는 NSAIDs 인 celecoxib 및 이의 구조 유사체인 2,5-dimethyl celecoxib 그리고 ibuprofen의 인간 암세포에 대한 imatinib 및 TNF-related apoptosis inducing ligand (TRAIL) 세포 독성 변화에 미치는 영향을 조사하였다. NSAID는 TRAIL 및 imatinib에 각각 약제 내성을 나타내는 간암 세포와 백혈병 세포에서 이들 약물의 세포독성을 증강시키는 활성을 나타내었다. NSAID는 ATF4/CHOP의 발현 증강으로 소포체 스트레스 및 오토파지(Autophagy, 자가포식)를 유도하였다. 이로 인한 DR5 발현 증강과 함께 c-FLIP 발현 억제로 TRAIL의 세포독성을 증강시키는 기전을 나타내었다. NSAID로 유도되는 오토파지 활성은 imatinib-resistant CD44^highK562 백혈병세포의 imatinib 감수성을 증강시켰으며, NSAID는 이 세포에서 높은 발현을 나타내는 다양한 stemness-related marker 단백질의 발현 감소를 촉진시키는 활성으로 세포사멸을 유도하는 것을 알 수 있었다. 이러한 결과는 NSAID의 오토파지 유도 활성이 TRAIL과 imatinib의 세포 독성을 증강시키는 것으로서, NSAID와 이들 약물과 병용 처리방법은 인간 암세포의 TRAIL 및 imatinib 내성을 극복 시킴과 동시에 암세포에 이들 약물의 독성 부작용을 감소시킬 수 있는 낮은 농도의 처리를 가능하게 할 것으로 사료된다.

• 비파괴검사학회지
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• 제33권5호
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• pp.443-451
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• 2013

음향방출기법은 구조물에 존재하는 손상 및 손상 메커니즘을 규명하는 가장 유효한 비파괴검사 수단으로 널리 이용되고 있다. 최근 이러한 재료 및 구조의 내부 손상의 실시간 모니터링이 가능한 기법을 활용하여 풍력 블레이드와 같은 대형 구조물의 건전성을 실시간으로 감시 가능하도록 하는 연구가 각광 받고 있다. 이 논문에서는 선행 연구를 통하여 개발된 신호 맵핑 기법을 사용하여 750 kW 블레이드에 외부 손상을 가정한 임의의 외부 충격을 가하여 위치 탐지 결과의 정확성을 확인하고, 100 kW 블레이드의 정하중 시험 시 발생하는 음향방출신호를 측정하여 손상이 발생된 것으로 의심되는 지역을 탐지하는 실험을 실시하였다. 실험 결과 발생된 모든 외부 충격신호에 대하여 낮은 오차범위를 가지는 결과를 보였으며, 정적하중실험동안 측정된 음향방출신호와 실제 손상 발생 위치의 비교를 통하여 새로운 신호 맵핑 기법으로 블레이드에서 발생되는 내부 손상을 매우 높은 정확도로 위치 표정이 가능함을 확인하였다.

• 한국전산구조공학회논문집
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• 제17권3호
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• pp.319-332
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• 2004

복합재료(FRP)는 재료적 고비강도, 고내구성 등으로 인하여 건설분야에 널리 사용되고 있어, 본 연구에서는 인발성형된 FRP 바닥판의 형상최적설계를 수행하였다. 최적설계의 정식화에서 목적함수는 단위모듈의 체적을 최소화하도록 하였으며, 설계변수는 바닥판 단면의 기하적 치수와 재료적 물성을 사용하였다. 반면 바닥판의 성능을 최대한 효율적으로 설계하기 위하여 설계 제약조건으로 처짐규정, 재료파괴 기준, 좌굴하중, 바닥판 최소두께와 응력을 사용하였다. 단면형상의 효율적 결정과 시공성을 고려하여 구조적 보조부재를 포함하지 않는 튜브 모양의 형상으로 제한하였으며, 최적화 알고리즘은 Index기법을 적용하여 수렴성을 극대화한 개선된 GAs를 사용하였다. 상용 프로그램인 ABAQUS를 사용하여 3차원 유한요소해석을 수행하였고, 구조해석 결과를 최적화 과정에 필요한 제약조건으로 활용하고, 민감도 분석을 수행하였다. 본 연구를 통하여 개발한 최적화 프로그램을 검증하기 위하여, 40m의 지간, 폭 12.14m에 주형 간격이 2.5m인 단순교를 대상으로 하였으며, 도로교 설계 기준을 만족하는 DB-24하중을 적용하였다. 복합재료의 재료로 E-glass섬유를 사용하였으며, 최적설계를 수행한 결과 인발성형공법에 의한 실용적인 단면을 제안하였다.

• 한국지진공학회논문집
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• 제11권2호
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• pp.95-104
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• 2007

세가지 형태의 고층 비정형 철근콘크리트 건물에 대해 OpenSees를 이용하여 비선형정적해석을 수행한 후, 해석결과와 진동대 실험결과를 비교하여 해석방법에 대한 검증을 수행하고, 해석결과 나타난 비정형 건물의 성능과 하부 필로티부분의 파괴양상을 분석하였다. 선정된 모델은 필로티층이 골조로만 이루어진 모델 (모델 1), 필로티층 내부중앙골조에 벽체가 있는 모델 (모델 2), 그리고, 필로티층의 한쪽 골조에 벽체가 있는 모델 (모델 3)이다. 철근과 콘크리트의 응력-변형률 관계를 섬유모델에 이식하여 비선형부분의 거동을 묘사하고, 벽체도 비선형모델을 이식한 트러스로 이루어진 MVLEM을 적용하였다. 그 결과 축력이 작용함에 따른 기둥의 전단강성변화, 벽체의 들뜸현상 등과 같이 진동대 실험에서 나타난 거동특성을 비교적 정확하게 묘사하였다. 초과강도 측면에서 하부골조에 벽체를 포함하고 있는 모델 2와 모델 3은 모델 1보다 2배 가까이 크다. 이와 같이 모델 2와 모델 3의 초과강도와 연성이 큰 이유는 모델 2와 모델 3의 경우 모델 1로 설계된 골조에 벽체가 낀 벽의 형태로 설계되었기 때문으로 보인다. 그리고, 연성의 측면에서 모델 1과 모델 3은 모델 2의 보다 1.17배 큰 것으로 나타났다. 모델 1과 모델 3의 경우 골조부분에 과도한 모멘트가 작용하여 파괴에 이른 반면, 모델 2는 하부전단벽의 전단파괴에 의해 파괴되었으며, 모델 1과 모델 3에 비하여 크게 작용한 전도모멘트로 인해 기둥에 작용하는 축력의 변화가 크게 발생하였다.

• 재활복지공학회논문지
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• 제6권1호
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• pp.45-50
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• 2012

흉 요추 보조기는 후만증 관련 증상의 진행을 예방하고 통증을 완화시키기 위한 목적으로 노인성 후만증 환자의 재활을 위하여 이용되고 있다. 최근 다양한 형태의 흉 요추 보조기가 개발되고 있으나 생체역학적 효과에 관한 연구가 미흡한 실정이다. 따라서 본 연구에서는 세 가지 형태 (Type 1, one-connecting frame type; Type 2, two-connecting frame type; Type 3, all-in-one type)의 흉 요추 보조기와 몸통 (trunk)의 유한요소 모델을 구현하여 보조기 착용 후 운동성 변화에 따른 몸통에서의 압력 분포 및 보조기의 응력을 비교 분석하였다. 신전 운동 시 몸통에서 확인되는 압력의 분산은 일체형의 형태를 가지는 Type 3에 의해서 가장 고르게 이루어졌으며 connecting frame 형태의 Type 1과 Type 2의 압력 분포 패턴은 크게 차이가 나지 않았다. 보조기 착용에 따른 몸통의 운동성은 Type 2 ($11.3{\sim}13.9^{\circ}$), Type 1 ($12.1{\sim}15.4^{\circ}$)와 비교하여 Type 3 ($8.5{\sim}9.4^{\circ}$)에 의하여 가장 크게 제한되었다. 모든 Type의 보조기는 20% 미만의 파단 가능성을 보였다. 따라서, 보조기 착용에 따른 등압 분포 및 운동성의 결과로 미루어 볼 때, 일체형의 흉 요추 보조기가 후만증 환자 재활에 있어 높은 효과를 제공할 것으로 사료된다.

• 한방안이비인후피부과학회지
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• 제29권3호
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• pp.27-41
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• 2016

Objectives : The purpose of this research is to understand melanin with both Korean and Western medicine.Methods : We investigated the comprehension of melanin in both western and Korean medicine through literature review and studied relationships between melanin and five viscera(五臟), especially liver(肝), spleen(脾), kidney(腎). We Also studied representative pigmentary disorders(melasma, vitiligo) in western and Korean medicine to figure out how to understand pigmentary disorders in oriental medicine.Results : The results are as follows. 1. Melanin is associate with liver, because free coursing(疎泄) function of liver is the origin of transport melanin to keratinocyte from melanocyte. Also, melanogenesis factors like MITF and CREB are closely associated with liver and pigmentary disorders occur frequently after stress conditions or women. 2. Melanin is absorbed and scattered in keratinocytes by the function of spleen. Pigmentary disorders result from failure of spleen and formation of phlegm-retained fluid(痰飮). 3. Kidney essence(腎精) is the origin of melanin formation. In addition, corticosteroid, the major hormone of melanogenesis is secreted by adrenalin and adrenalin belongs to kidney(腎) in Korean medicine. 4. Melasma is created by disorder of melanin transport and absorbtion, so melasma is associated liver (肝) and spleen(脾). Therefore the treatment for melasma may focus on improvement function of liver and spleen. 5. The destruction of melanocyte or abnormal melanogenesis by disorder of the immune system, metabolic and affective disorders can make vitiligo, so vitiligo is associated with liver and kidney which are major part of melanin formation. Therefore the treatment of vitiligo can focus on improvement function of liver(肝) and kidney(腎).Conclusion : We compared Korean and western medicine to understand melanin. We also interpreted the mechanism of melanin and pigmantary disorders in western medicine and considered the relationship with visceral manifestation theory(臟象論) in traditional Korean medicine. Further studies are needed to apply comprehension of melanin to clinical stage.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.20-20
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• 2017

Plant genomes include heterochromatic loci that consist of repetitive sequences and transposable elements. LTR retrotransposon is the major class of transposons in advanced plants in terms of proportion in plant genome. The elements contribute not only to genome size but also to genome stability and gene expression. A number of cases have been reported transposon insertions near genic regions affect crop traits such as fruit pigments, stress tolerance, and yields. Functional LTR retrotransposons produce extrachromosomal DNA from genomic RNA by reverse transcription that takes place within virus-like-particles (VLPs). DECREASED DNA METHYLATION 1 (DDM1) plays important roles in maintaining DNA methylation of heterochromatin affecting all sequence contexts, CG, CHG, and CHH. Previous studies showed that ddm1 mutant exhibits massive transcription of retrotransposons in Arabidopsis, but only few of them were able to create new insertions into the genome. RNA-dependent RNA POLYMERASE 6 (RDR6) is known to function in restricting accumulation of transposon RNA by processing the transcripts into 21-22 nt epigenetically activated small interfering RNA (easiRNA). We purified VLPs and sequence cDNA to identify functional LTR retrotransposons in Arabidopsis ddm1 and ddm1rdr6 plants. Over 20 LTR copia and gypsy families were detected in ddm1 and ddm1rdr6 sequencing libraries and most of them were not reported for mobility. In ddm1rdr6, short fragments of ATHILA gypsy elements were detected. It suggests easiRNAs might regulate reverse transcription steps. The highest enriched element among transposon loci was previously characterized EVADE element. It has been reported that active EVADE element is more efficiently silenced through female germline than male germline. By genetic analyses, we found ddm1 and rdr6 mutation affect maternal silencing of active EVADE elements. DDM1-GFP protein accumulated in megaspore mother cell but was not found in mature egg cell. The fusion protein was also found in early embryo and maternal DDM1-GFP allele was more dominantly expressed in the embryo. We observed localization of DDM1-GFP in Arabidopsis and DDM1-YFP in maize and found the proteins accumulated in dividing zone of root tips. Currently we are looking at cell cycle dependency of DDM1 expression using maize system. Among 10 AGO proteins in Arabidopsis, AGO9 is specifically expressed in egg cell and shoot meristematic cells. In addition, mutation of AGO9 and RDR6 caused failure in maternal silencing, implying 21-22 nt easiRNA pathway is important for retrotransposon silencing in female gametophyte or/and early embryo. On the other hand, canonical 24 nt sRNA-directed DNA methylation (RdDM) pathways did not contribute to maternal silencing as confirmed by this study. Heat-activated LTR retrotransposon, ONSEN, was not silenced by DDM1 but the silencing mechanisms require RdDM pathways in somatic cells. We will propose distinct mechanisms of LTR retrotransposons in germline and somatic stages.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
• /
• pp.97-97
• /
• 2017

Plant genomes include heterochromatic loci that consist of repetitive sequences and transposable elements. LTR retrotransposon is the major class of transposons in advanced plants in terms of proportion in plant genome. The elements contribute not only to genome size but also to genome stability and gene expression. A number of cases have been reported transposon insertions near genic regions affect crop traits such as fruit pigments, stress tolerance, and yields. Functional LTR retrotransposons produce extrachromosomal DNA from genomic RNA by reverse transcription that takes place within virus-like-particles (VLPs). DECREASED DNA METHYLATION 1 (DDM1) plays important roles in maintaining DNA methylation of heterochromatin affecting all sequence contexts, CG, CHG, and CHH. Previous studies showed that ddm1 mutant exhibits massive transcription of retrotransposons in Arabidopsis, but only few of them were able to create new insertions into the genome. RNA-dependent RNA POLYMERASE 6 (RDR6) is known to function in restricting accumulation of transposon RNA by processing the transcripts into 21-22 nt epigenetically activated small interfering RNA (easiRNA). We purified VLPs and sequence cDNA to identify functional LTR retrotransposons in Arabidopsis ddm1 and ddm1rdr6 plants. Over 20 LTR copia and gypsy families were detected in ddm1 and ddm1rdr6 sequencing libraries and most of them were not reported for mobility. In ddm1rdr6, short fragments of ATHILA gypsy elements were detected. It suggests easiRNAs might regulate reverse transcription steps. The highest enriched element among transposon loci was previously characterized EVADE element. It has been reported that active EVADE element is more efficiently silenced through female germline than male germline. By genetic analyses, we found ddm1 and rdr6 mutation affect maternal silencing of active EVADE elements. DDM1-GFP protein accumulated in megaspore mother cell but was not found in mature egg cell. The fusion protein was also found in early embryo and maternal DDM1-GFP allele was more dominantly expressed in the embryo. We observed localization of DDM1-GFP in Arabidopsis and DDM1-YFP in maize and found the proteins accumulated in dividing zone of root tips. Currently we are looking at cell cycle dependency of DDM1 expression using maize system. Among 10 AGO proteins in Arabidopsis, AGO9 is specifically expressed in egg cell and shoot meristematic cells. In addition, mutation of AGO9 and RDR6 caused failure in maternal silencing, implying 21-22 nt easiRNA pathway is important for retrotransposon silencing in female gametophyte or/and early embryo. On the other hand, canonical 24 nt sRNA-directed DNA methylation (RdDM) pathways did not contribute to maternal silencing as confirmed by this study. Heat-activated LTR retrotransposon, ONSEN, was not silenced by DDM1 but the silencing mechanisms require RdDM pathways in somatic cells. We will propose distinct mechanisms of LTR retrotransposons in germline and somatic stages.

• 한국언론정보학보
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• 제16권
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• pp.168-206
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• 2001

This study attempts to examine the relationships between the major market-based media and the government after closing military regime era, 1961-1987. After the military regime was collapsed, while the mass media in Korea obtained independence and autonomy from government, they have been confronted with the terrible competition not so much comparatively as before. The watchdog role in the traditional liberalism, which is regarded as normative relationship between the media and the government would be transformed in accordance with the market condition and the maturity of democracy. Thus, the watchdog metaphor has been variously deviated in rower-centered society; lap dog, guard dog, attack dog. liberalists argue that the primary democratic role of the media is to art as a public watchdog overseeing the state. Social democrats, however, criticize them as simplistic conception which could be only applied to the government. They argue that the media should be seen as a source of redress against the abuse of all forms of power over others; the home, the economy, and the civil society. The lap dog view is that the media is overwhelmingly dependent on the established power structure contrary to the watchdog. While the guard dog perspective is a means to preserve the power structure alarming with playing 'conflict role', the attack do8 aims to the private interest of the media in intruding into the politics. The attack dog perspective by T. Patterson could be composed of the interpretive style of report, the game schema report over the policy schema in the election, and the negativism against politics and government. The market-dominant press has been likely to transform from lap-guard dog into attack-guard dog. In Roh Tae Woo government(1988-1992), while the press was a lessened lap-guard dog before three parties merger in 1990, after merger the press had been transformed as the reinforced lap-guard dog because this merger entailed joint, party-to-party negotiations, and the formation of the new party preceded by dissolution of the ruling blot. In the early stage of Kim Young Sam government(1993-1997), the press has kept in pace with the reform movement drive-forced by the government. However, the press withdrew the support of Kim's reform in reaching the level of threat to ruling bloc. The press coalesced only circumstantially with government and was interested in preserving some margin of independence. The failure of Kim's reform proved the political muscle of the press in post-autho-ritarianism. In the middle stage of Kim Dae Jung government (1998-) that resulted in the shift of power structure as once-opposition party leader, the stress has been a manifested attack-guard dog owing to the anti-cold war policy, the realignment policy of power, and the minority-base of Kim's government. The press has endeavored to hold political communication within limits relatively less threatening to the established order.