• Molecular & Cellular Toxicology
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• 제4권2호
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• pp.144-149
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• 2008

Despite versatile activity (cancericidal, antimicrobial, hypoxia inducible factor (HIF) inhibition, immune deactivation of DNA bis-intercalation agent, echinomycin, its specific mechanism has been elusive. Of these novel mechanisms, we reported that using human colon cancer cells (HT-29), apoptotic machinery induced by echinomycin might be dependent of caspase-3 pathway. Despite a partial enlightenment of prototypic signal path triggered by echinomycin, the role of Bcl-2 in this signaling pathway is unclear. To address this issue, we explored whether or not echinomycin would overcome the anti-apoptotic impact of Bcl-2 in HT-29 cells by the controlled Bcl-2 overexpression. Prior to this proof, we confirmed that echinomycin induces mitochondrial depolarization, then triggering the mitochondrial pathway of apoptosis with an involvement of upstream cas-pases-3. Transiently transfection with inactive Bax-DNA failed to prevent echinomycin-induced apoptosis in HT-29 cells. To dissect the role of Bcl-2 in echinomycin-induced apoptosis, HT-29 cells were transiently transfected with Bcl-2 DNA for overexpression and then treated with echinomycin for 24h. Combined analyses of DNA fragmentation and flow cytometric analysis clearly verified that echinomycin-induced apoptosis was drastically attenuated by Bcl-2 overexpression, whereas a control vector rarely affected echinomycin-induced apoptosis. Collectively, these data verify that Bcl-2 regulates echinomycin-induced apoptosis in HT-29 cells. To my knowledge, this is the first evidence that of diverse, structured minor groove binders (MGB), the prototypic echinomycin might control the apoptotic signaling via Bcl-2-mitochondrial pathway.

• Asian Pacific Journal of Cancer Prevention
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• 제15권23호
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• pp.10057-10059
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• 2015

Positron emission tomography (PET) as the functional component of current hybrid imaging (like PET/CT or PET/MRI) seems to dominate the horizon of medical imaging in coming decades. $^{18}$Flourodeoxyglucose ($^{18}FDG$) is the most commonly used probe in oncology and also in cardiology and neurology around the globe. However, the major capital cost and exorbitant running expenditure of low to medium energy cyclotrons (about 20 MeV) and radiochemistry units are the seminal reasons of low number of cyclotrons but mushroom growth pattern of PET scanners. This fact and longer half-life of $^{18}F$ (110 minutes) have paved the path of a centralized model in which $^{18}FDG$ is produced by commercial PET radiopharmacies and the finished product (multi-dose vial with tungsten shielding) is dispensed to customers having only PET scanners. This indeed reduced the cost but has limitations of dependence upon timely arrival of daily shipments as delay caused by any reason results in cancellation or rescheduling of the PET procedures. In recent years, industry and academia have taken a step forward by producing low energy, table top cyclotrons with compact and automated radiochemistry units (Lab-on-Chip). This decentralized strategy enables the users to produce on-demand doses of PET probe themselves at reasonably low cost using an automated and user-friendly technology. This technological development would indeed provide a real impetus to the availability of complete set up of PET based molecular imaging at an affordable cost to the developing countries.

• 한국지진공학회논문집
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• 제3권1호
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• pp.67-74
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• 1999

이 연구에서는 단일 산란이론을 이용하여 경상분지에서 얻어진 국소 미소지진의 자료를 1.5-1.8Hz 사이의 주파수 영역에서 몇 개의 구간으로 나누어 대역 통과 필터링을 g여 coda 파의 진폭 감쇠로부터 Q값을 결정하였다 Coda Q 값은 Qc=Q0 fn 형태의 주파수 의존 양상을 보여주며 Q0 값은 83.9-155.9 n 값은 0.76에서 1.05 사이로 나타났다 산란 감쇠와 고유감쇠를 고려하여 감쇠가 순전히 산란에 의해서만 일어난다고 가정했을 때 최소 평균 자유경로를 51.-56km 이고 비탄성 감쇠계수는 0.0093-0.0098 로 나타났다 진앙과 관측소간의 경로가 단층지역을 지나는 것이 다른 경로를 지나오는 것보다 높은 감쇠와 강한 주파수 의존성을 보여준다.

• 한국융합학회논문지
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• 제9권7호
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• pp.33-40
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• 2018

지능정보기술과 에너지기술의 융합은 단순히 기술 자체 뿐 아니라 사회, 제도, 조직 전반의 변화를 수반하기 때문에 수많은 이해관계자들에게 영향을 미친다. 따라서 자원개발과 발전, 석유화학 중심의 전통 에너지 산업에 대한 경로 의존성에서 벗어나 새로운 산업을 창출하기 위해서는 미래에 도달하고자하는 선호 미래를 먼저 그리고 이를 실현하기 위한 전략을 고민하는, 백캐스팅(Backcasting) 관점의 접근이 필요하다. 본 연구에서는 이러한 백캐스팅 관점에서 지능정보기술이 가져올 미래 에너지 산업의 변화 양상을 살펴보고 국가 관점에서의 에너지 정책 목표 달성, 그리고 각 이해관계자들의 이익을 동시에 만족시킬 수 있는 미래 에너지 서비스 모델을 도출하였다. 이후, 미래 에너지 서비스가 실현되기 위한 기술적 선결 조건을 분석하고, 세부적인 구성 기술과 현재 시점에서 중점 R&D가 필요한 분야를 제시하였다.

• Human Ecology Research
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• 제52권6호
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• pp.561-571
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• 2014

This study investigated the relationships between the husband's support, depression, parenting self-efficacy, and parenting behavior of Korean American mothers and their children's self-esteem. The participants were 113 Korean American child-mother dyads (grades 3-8) from Southern California, USA. The data, including the mothers' parenting behavior as assessed by their children, were collected from self-report questionnaires. A path analysis indicated that the effects of the above mentioned variables on the children's self-esteem depended on the subscale model of the parenting behavior. In every subscale model of parenting behavior, the husband's support was positively related to the parenting self-efficacy and the mother's depression was negatively related to the parenting self-efficacy. Further, in the warmth-acceptance model, the husband's support was positively related to the parenting behavior, the mother's depression was negatively related to the parenting behavior, parenting self-efficacy was positively related to both the parenting behavior and the children's self-esteem, and the parenting behavior was positively related to the children's self-esteem. In the rejection-restriction model, the husband's support was negatively related to the parenting behavior, the mother's depression was positively related to the parenting behavior, the parenting self-efficacy was negatively related to the parenting behavior and was positively related to the children's self-esteem, and the parenting behavior was negatively related to the children's self-esteem. In the permissiveness-nonintervention model, the parenting behavior was negatively related to the children's self-esteem. These results, particularly the dependence on the subscale model of parenting behavior, will be helpful in understanding the effects of parenting on Korean American children's self-esteem.

• 대한토목학회논문집
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• 제4권2호
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• pp.55-64
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• 1984

본(本) 논문(論文)에서는 콘크리트의 점진적(漸進的) 인장파괴현상(引張破壞現象)을 해석(解析)할 수 있는 증분형(增分形)이며, 진로종속적(進路從屬的)이고, 텐서적으로 불변성(不變性)인 비선형구성(非線型構成)모델이 제안(提案)되었다. 전(全) 변형도(變形度)는 탄성성분(彈性成分)과 비탄성성분(非彈性成分)의 합(合)으로 표시(表示)된다. 콘크리트내부(內部)에는 미세균열(微細龜裂)의 근원(根源)이 되는 약(弱)한 면(面)들이 모든 방향(方向)으로 좌우(左右)하며, 이 약(弱)한 면(面)에서의 법선응력(法線應力)은 법선변형도(法線變形度)의 함수라고 가정된다. 이와 같은 근본개념(根本槪念)아래 가상(假想)일의 원리(原理)로부터 콘크리트의 접선강도(接線剛度)가 유도된다. 본(本) 이론(理論)은 비비례하중(非比例荷重)이나 주응력(主應力)의 방향(方向)이 변(變)하는 경우 등의 일반적(一般的)인 하중상태(荷重狀態)에 적용할 수 있으며, 이것이 본(本) 모델의 주요(主要)한 목적이 될 수 있다. 본(本) 이론(理論)을 변형연화현상(變形軟化現象)을 보이는 직접인장실험자료(直接引張實驗資料)와 비교한 결과 좋은 일치를 얻었다.

• 천문학회보
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• 제42권1호
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• pp.49.2-49.2
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• 2017

Star forming dwarf galaxies in various environments are attractive objects for investigating the environmental effects on chemical evolution of dwarf galaxies. Using SDSS DR7 spectroscopic data and GALEX ultraviolet (UV) imaging data, we study the chemical properties of star forming dwarf galaxies in various environments of the Virgo cluster, Ursa Major group, and field. We derived gas-phase abundance, galaxy mass, and UV specific star formation rate (sSFR) of subsample, early-type (ETD) and late-type star forming dwarf (LTD) galaxies, which are divided by visually classified galaxy morphology. We found no O/H enhancement of LTDs in cluster and group environments compared to the field, implying no environmental dependence of the mass-metallicity relation for LTDs. LTDs in the Virgo cluster and Ursa Major group have similar sSFR at a given galaxy mass, but they exhibit systematically lower sSFR than those in isolated field environment. We suggest that LTDs in the Virgo cluster are an infalling population that was recently accreted from the outside of the cluster. We found that ETDs in the Virgo cluster and Ursa Major group exhibit enhanced O/H compared to those in the field. However, no distinct difference of N/O of galaxies between different environments. The chemically evolved ETDs in the Virgo cluster and Ursa Major group also show similar mass-sSFR relation, but systematically lower sSFR at a fixed galaxy mass compared to the field counterparts. We suggest that ETDs in the Virgo cluster and Ursa Major group have evolved under the similar local environments. We also discuss the evolutionary path of ETDs and LTDs with respect to the environmental effects of ram pressure stripping and galaxy interaction/merging.

• 한국재료학회지
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• 제22권8호
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• pp.409-415
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• 2012

$TiO_2$ thin films for high energy density capacitors were prepared by r.f. magnetron sputtering at room temperature. Flexible PET (Polyethylene terephtalate) substrate was used to maintain the structure of the commercial film capacitors. The effects of deposition pressure on the crystallization and electrical properties of $TiO_2$ films were investigated. The crystal structure of $TiO_2$ films deposited on PET substrate at room temperature was unrelated to deposition pressure and showed an amorphous structure unlike that of films on Si substrate. The grain size and surface roughness of films decreased with increasing deposition pressure due to the difference of mean free path. X-ray photoelectron spectroscopy (XPS) analysis revealed the formation of chemically stable $TiO_2$ films. The dielectric constant of $TiO_2$ films was significantly changed with deposition pressure. $TiO_2$ films deposited at low pressure showed high dissipation factor due to the surface microstructure. The dielectric constant and dissipation factor of films deposited at 70 mTorr were found to be 100~120 and 0.83 at 1 kHz, respectively. The temperature dependence of the capacitance of $TiO_2$ films showed the properties of class I ceramic capacitors. $TiO_2$ films deposited at 10~30 mTorr showed dielectric breakdown at applied voltage of 7 V. However, the films of 500~300 nm thickness deposited at 50 and 70 mTorr showed a leakage current of ${\sim}10^{-8}{\sim}10^{-9}$ A at 100 V.

• Structural Engineering and Mechanics
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• 제17권1호
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• pp.51-68
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• 2004

Since the linear elastic fracture analysis has been proved to be insufficient in predicting the failure of strain hardening materials, a number of fracture concepts have been studied which remain applicable in the presence of plasticity near a crack tip. This work thereby presents a new finite element model to predict the elastic-plastic crack-tip field and fatigue life of center-cracked panels(CCP) with ductile fracture under large-scale yielding conditions. Also, this study has been carried out to investigate the path-dependence of J-integral within the plastic zone for elastic-perfectly plastic, bilinear elastic-plastic, and nonlinear elastic-plastic materials. Based on the incremental theory of plasticity, the p-version finite element is employed to account for the accurate values of J-integral, the most dominant fracture parameter, and the shape of plastic zone near a crack tip by using the J-integral method. To predict the fatigue life, the conventional Paris law has been modified by substituting the range of J-value denoted by ${\Delta}J$ for ${\Delta}K$. The experimental fatigue test is conducted with five CCP specimens to validate the accuracy of the proposed model. It is noted that the relationship between the crack length a and ${\Delta}K$ in LEFM analysis shows a strong linearity, on the other hand, the nonlinear relationship between a and ${\Delta}J$ is detected in EPFM analysis. Therefore, this trend will be depended especially in the case of large scale yielding. The numerical results by the proposed model are compared with the theoretical solutions in literatures, experimental results, and the numerical solutions by the conventional h-version of the finite element method.

• 한국위성정보통신학회논문지
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• 제9권4호
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• pp.111-116
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• 2014

모바일 디바이스의 확산과 네트워크 진화에 따라 모바일 앱의 응용분야와 수요가 증가하고 있다. 이에 따라 모바일 앱은 특정한 소수 글로벌 회사의 운영체계(OS)와 플랫폼에 종속되는 경향이 심화되고 있다. 즉, 모바일 앱의 OS는 구글의 안드로이드나 애플의 iOS에 편중되고 플랫폼도 애플 앱 스토어(App Store) 등에 종속되어, 상호운용성이나 호환성을 보장하기가 용이하지 않은 상황이다. 본 연구 결과, HTML5 기반으로 모바일 앱을 개발하면 이기종 디바이스와 서비스간의 상호운용성이나 호환성이 담보되어 특정 OS에 종속되지 않고 멀티 플랫폼에 유연하게 대응할 수 있기 때문에 개발자뿐만 아니라 일반 사용자의 사용의도 측면에서도 긍정적인 평가를 받았다. 또한, 모바일 앱 개발자는 기술적 경로의존성이 강한 경향이 있기 때문에 중소벤처기업의 모바일 앱 개발자에 대한 정부차원의 제반 지원과 인력양성이 필요한 것으로 분석되었다.