• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1137-1143
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• 2019

Hepatitis E virus (HEV) accounts for 20 million infections in humans worldwide. In most cases, the infections are self-limiting while HEV genotype 1 infection cases may lead to lethal infections in pregnant women (~ 20% fatality). The lack of small animal models has hampered detailed analysis of virus-host interactions and HEV-induced pathology. Here, by employing a recently developed culture-adapted HEV, we demonstrated that methyltransferase, a non-structural protein, strongly inhibits melanoma differentiation-associated gene 5 (MDA5)-mediated activation of type I interferon responses. Compared to uninfected controls, HEV-infected cells display significantly lower levels of $IFN-{\beta}$ promoter activation when assessed by luciferase assay and RT-PCR. HEV genome-wide screening showed that HEV-encoded methyltransferase (MeT) strongly inhibits MDA5-mediated transcriptional activation of $IFN-{\beta}$ and $NF-{\kappa}B$ in a dose-responsive manner whether or not it is expressed in the presence/absence of a tag fused to it. Taken together, current studies clearly demonstrated that HEV MeT is a novel antagonist of MDA5-mediated induction of $IFN-{\beta}$ signaling.

• 한국과학교육학회지
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• 제31권5호
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• pp.758-769
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• 2011

이 연구의 목적은 과학학습 동기체계를 알아보기 위한 SL-BIS/BAS와 자기효능감의 관계를 알아보는 것이다. 이를 위해 초등학교 4학년 496명, 중학교 2학년 425명이 과학학습 행동억제/활성화체계 검사 도구(SL-BIS/BAS)와 자기효능감 검사지를 수행하였으며, 회수된 검사지를 바탕으로 집단별 과학학습 행동억제/활성화체계를 파악하고 두 체계와 자기효능감과의 관계를 분석하였다. 이 연구에서 밝혀진 결과는 다음과 같다. 첫째, 과학학습 행동억제체계에 대한 민감성은 4학년보다 8학년이 더 높았으나 과학학습 행동활성화체계에 대한 민감성과 자기효능감은 8학년보다 4학년이 더 높았다. 둘째, 자기효능감은 과학학습 행동억제체계와 낮은 부적상관이 있으며, 과학학습 행동활성화 체계와 정적상관이 있었다. 또한 자기효능감에 대한 두 체계의 설명력은 41%로 나타나, 자기효능감과 밀접한 관련이 있음을 알 수 있다. 이 연구에서 과학학습 행동억제/활성화체계의 분석을 통해 학습자 변인에 따른 동기의 차이, 그리고 동기와 관련변인의 관계를 확인할 수 있었다. 이로써 동기와 관련변인을 근본적으로 이해하여, 학습자에게 적합한 지도 계획을 세우기 위한 기초자료로 활용할 수 있을 것이다.

• Steel and Composite Structures
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• 제26권5호
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• pp.573-582
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• 2018

This study develops and numerically verifies an innovative seismically resilient bracing system. The proposed self-centering tension-only brace (SC-TOB) is composed of a tensioning system to provide a self-centering response, a frictional device for energy dissipation, and a high-strength steel cable as a bracing element. It is considered to be an improvement over the traditional self-centering braces in terms of lightness, high bearing capacity, load relief, and double-elongation capacity. In this paper, the mechanics of the system are first described. Governing equations deduced from the developed analytical model to predict the behavior of the system are then provided. The results from a finite element validation confirm that the SC-TOB performs as analytically predicted. Key parameters including the activation displacement and load, the self-centering parameter, and equivalent viscous damping are investigated, and their influences on the system behavior are discussed. Finally, a design procedure considering controlled softening behavior is developed and illustrated through a design example.

• 농촌지도와개발
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• 제11권1호
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• pp.95-110
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• 2004

The purposes of this study were to analyze rural youth's leisure activity and to suggest measures for activation. This study was conducted by review of literature and questionnaire, The data was collected from 1,209 stratified cluster random sampled rural youth who are in middle school and high school. To analyze the data, SPSS/WIN program was employed. The major finding of the study were as follows: 1) About 30% of rural youths had less than 1-2 hours for leisure activity in daily life and more than 8 hours for leisure activity during the weekend, and over 40% of rural youths had no plan for leisure activity. 1) They recognized that leisure activity made them enjoy common life, decrease their stress, and get new experience far self-development, 3) participation in sports, organized-activity and self-directed activity of the middle schools youths were higher compare to youths in high schools, 4) to activate leisure life, rural youths expected to get a) direct support for participating leisure activity expenses(27%), b) develop and diffusion of diverse and interesting leisure programs(23%), and c) securing appropriate leisure facilities(22%).

• 한국분말재료학회지
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• 제25권2호
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• pp.109-119
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• 2018

The objective of this study is to reveal the sintering mechanism of mixed Ti-6Al-4V powders considering the densification and the homogenization between Ti and Al/V particles. It is found that the addition of master alloy particles into Ti enhances densification by the migration of Al into the Ti matrix prior to the self-diffusion of Ti. However, as Ti particles become coarser, sintering of the powders appears to be retarded due to slower inter-diffusion of the particles due to the reduced surface energies of Ti. Such phenomena are confirmed by a series of dilatometry tests and microstructural analyses in respect to the sintering temperature. Furthermore, the results are also consistent with the predicted activation energies for sintering. The energies are found to have decreased from 299.35 to $135.48kJ{\cdot}mol^{-1}$ by adding the Al/V particles because the activation energy for the diffusion of Al in ${\alpha}-Ti$ ($77kJ{\cdot}mol^{-1}$) is much lower than that of the self-diffusion of ${\alpha}-Ti$. The coarser Ti powders increase the energies from 135.48 to $181.16kJ{\cdot}mol^{-1}$ because the specific surface areas of Ti decrease.

• Bulletin of the Korean Chemical Society
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• 제24권11호
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• pp.1590-1598
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• 2003

In this paper we have presented the results for viscosity and self-diffusion constants of model systems for four liquid n-alkanes ($C_{12}, C_{20}, C_{32}, and C_{44}$) in a canonical ensemble at several temperatures using molecular dynamics (MD) simulations. The small chains of these n-alkanes are clearly $<{R_{ee}}^2>/6<{R_g}^2>>1$, which leads to the conclusion that the liquid n-alkanes over the whole temperatures considered are far away from the Rouse regime. Calculated viscosity ${\eta}$ and self-diffusion constants D are comparable with experimental results and the temperature dependence of both ${\eta}$ and D is suitably described by the Arrhenius plot. The behavior of both activation energies, $E_{\eta}$ and $E_D$, with increasing chain length indicates that the activation energies approach asymptotic values as n increases to the higher value, which is experimentally observed. Two calculated monomeric friction constants ${\zeta}$ and ${\zeta}_D$ give a correct qualitative trend: decrease with increasing temperature and increase with increasing chain length n. Comparison of the time auto-correlation functions of the end-to-end vector calculated from the Rouse model for n-dodecane ($C_{12}$) at 273 K and for n-tetratetracontane ($C_{44}$) at 473 K with those extracted directly from our MD simulations confirms that the short chain n-alkanes considered in this study are far away from the Rouse regime.

• 한국콘텐츠학회논문지
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• 제17권8호
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• pp.301-311
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• 2017

본 연구는 동기 활성화의 개인 성향이 마약 이용을 예측하는 변인으로 작용하는지와 개별 감성과 상호작용하여 마약퇴치 광고의 반응에 영향을 미치는지 조사하였다. 동기 활성화는 식량과 같이 생존에 필요한 요소들을 성취하기 위한 동기(접근 동기), 혹은 천적과 같이 위협적인 요소들을 회피하려는 동기(회피 동기)가 발현되는 정도를 의미한다. 개별 감성은 기쁨, 슬픔, 공포를 유도하는 광고 방식의 차이를 의미한다. 실험을 자가 보고와 생리적 반응을 이용하여 진행하였으며, 총 80명이 참여하였다. 연구 결과, 접근 동기의 활성화는 마약 이용을 예측하고, 방어 동기의 활성화는 예측하지 않는 것으로 나타났다. 마약퇴치 광고의 시청에서 접근 동기의 활성화는 자가 보고 반응에서는 차이를 나타내지 않았지만 생리적 반응에서 차이를 발현시켰고, 방어 동기의 활성화 성향은 자가 보고, 생리적 반응 전부에서 차별적 반응을 구현하는 것으로 나타났다. 전체적으로 접근 동기의 활성화가 높은 개인들을 마약퇴치 광고의 표적으로 삼을 수 있으며 이를 위해서는 긍정적 감성을 유도하는 방식이 중요하다는 단서를 제공하고 있다.

• The Journal of Korean Physical Therapy
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• 제21권3호
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• pp.47-52
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• 2009

Purpose: To examine the correlation between the gait speed and muscle activation or foot pressure in stroke patients. Methods: Twenty five functionally ambulant stroke patients (male/female: 15/10, mean age: $57.65\pm2.30$) were enrolled in this study. The patients were asked to walk on a plate at a self-selected and comfortable speed. Three walking trials were obtained and then averaged for data analysis. The gait speed and foot pressure were measured from a RS-Scan system. Activation of the quadriceps femoris muscle and biceps hamstring muscle (%RVC) were recorded using ProComp $Infiniti^{TM}$. Results: There was a significant positive correlation between Hamstring muscle activation (%RVC) and gait speed. The gait speed correlated with the foot pressure of the lateral metatarsal zone (M3-5) in the affected side. There was a correlation between the gait speed and the foot pressure of the lateral metatarsal (M3-5) and heel (medial, lateral) zone in the less-affected side. Conclusion: The gait speed is related to hamstring muscle activation and the characteristics of foot pressure. This information was observed in both the affected and less-affected sides, suggesting that rehabilitation programs should be implemented on both sides.

• 한국방사선학회논문지
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• 제15권4호
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• pp.415-427
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• 2021

한국원자력의학원에서는 50 MeV 사이클로트론의 빔 라인을 이용하여 연구자들에게 다양한 빔 조사 서비스를 수행하고 있다. 특히 중성자 빔 서비스는 양성자와 베릴륨의 핵반응을 이용하기 때문에 높은 전류를 사용하므로 조사 시료의 방사화 가능성이 높아진다. 본 연구에서는 연구자들이 선호하는 35 MeV 20 ㎂ 중성자 빔 서비스에 의해 발생 가능한 방사화에 대해 MCNP 6.2와 FISPACT-II 4.0을 이용해 평가했다. 평가결과 철, 구리, 텅스텐 시료는 1시간 이상 조사하는 경우 장반감기 핵종이 생성되는 방사화가 발생하여 자체처분농도를 초과했다. 매일 2시간 사용 조건에서 건축물에 대한 방사화는 발생하지 않았고 조사실 내부 공기의 방사화로 인한 종사자의 내부피폭은 매우 미비했고, 이 공기를 배기하는 경우 배출기준도 만족했다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2002년도 봄 학술발표논문집 Vol.29 No.1 (A)
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• pp.847-849
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• 2002

인공면역시스템에서 중요한 특징중의 하나는 지속적으로 변화하는 환경에서 자기(self)의 유동적인 패턴을 동적으로 학습하고 비자기(non-self)에 대한 새로운 패턴을 예측하는데 있다. 본 논문은 자기적 용(self-adaptation)의 인공면역체계 특성을 기반으로하여 설계된 dynamics(동적 클론선택 알고리즘, dynamic clonal selection algorithm)의 역할을 논한다. 시스템의 세가지 중요한 변수인 자기내성 기간(Tolerisation Period). 연역 반응 임계값(activation threshold). 수명(life span)에 따라 변화하는 dynamics의 성능을 네트워크 침입에서 흔히 발견되는 시나리오를 모의실험하여 평가한다