• 한국해양공학회지
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• 제6권1호
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• pp.131-139
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• 1992

The understanding and appllication of fatigue crack propagation mechanism in variable amplitude loading is very important for life prediction of the air travel structures. Particularly, the retardation and arrest behavior of fatigue crack propagation by single tension overloading is essential to the understanding and appllication of fatigue crack propagation mechanism in variable amplitude loading. Numerous studies of the retardation behavior have been performed, however investigations of the arrest behavior have not been enough yet. As for the arrest behavior, Willenborg had reported that the overload shut-off ratio $[R_{so}=(K_{OL})/K_{max})_{crack arrest}]$ had been the material constant, but recently several investigators have reported that the overload shut-off ratio depends upon the stress ratio. In this study, authors have investigated the effect of stress ratio on the threshold overload shut-off ratio to generate arrest of fatigue crack growth in high tensile aluminum alloy 7075-T735 which have used in material for air travel structures, It has been $-0.4\leqqR\leqq0.4$ till now, the region of stress ratio investigated. The threshold overload shut-off ratio has decreased as stress ratio has increased in overall region of -$-0.4\leqqR\leqq0.4$ and the linearity has been seen in this material. Moreover, the experimental equation between $R_{so}$ and R has been made; The relation has been $R_{so}=-R+2.6$.

• Journal of Welding and Joining
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• 제33권1호
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• pp.35-40
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• 2015

Recently, there have been the increase of ship size and the development of oil and gas in arctic region. These trends have led to the requirements such as high strength, good toughness at low temperature and good weldability for prevent of brittle fracture at service temperature. There has been the key issue of crack arrestability in large size structure such as container ship. In this report for the first time, crack arrest toughness of thick steel plate welds was evaluated by large scale ESSO test for estimate of brittle crack arrestability in thick steel plate. For large structures using thick steel plates, fracture toughness of welded joint is an important factor to obtain structural integrity. In general, there are two kinds of design concepts based on fracture toughness: crack initiation and crack arrest. So far, when steel structures such as buildings, bridges and ships were manufactured using thick steel plates (max. 80~100mm in thickness), they had to be designed in order to avoid crack initiation, especially in welded joint. However, crack arrest design has been considered as a second line of defense and applied to limited industries like pipelines and nuclear power plants. Although welded joint is the weakest part to brittle fracture, there are few results to investigate crack arrest toughness of welded joint. In this study, brittle crack arrest designs were developed for hatch side coaming of large container ships using arrest weld, hole, and insert technology.

• 한국산학기술학회논문지
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• 제15권2호
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• pp.760-766
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• 2014

본 연구는 심정지 환자의 생존율을 비교분석하여, 심정지환자의 생존에 미치는 영향요인을 규명하고자 시도하였다. 조사대상은 2010년 일개 도에서 119 구급대가 이송한 18세 이상 심정지 환자 4,092명으로 하였고, 구급일지와 심폐정지환자 응급처치 세부상황표, 인명소생 추천서를 유스타인 형식 조사지에 기록하였다. 연구결과 생존에 영향을 미치는 요인은 산소공급, 기도유지, 정맥로 확보, 병원도착 소요시간, 현장처치시간, 발생장소, 일반인에 의한 심폐소생술, 동승 구급대원의 자격, 자발순환 회복장소 등이었다. 결론적으로 심정지 환자에 대한 119 구급대의 응급처치는 생존율을 유의하게 높였다. 조기 제세동, 산소공급, 기도유지, 정맥로 확보 등 병원전 응급처치가 생존에 큰 영향을 미치므로, 119 구급대 중 1급 응급구조사의 인원증가를 위한 정책을 제정하고, 119 구급대의 응급처치 시행률을 높일 수 있는 방안을 마련하여 심정지 환자의 생존율을 개선해야겠다.

• 대한임상독성학회지
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• 제19권1호
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• pp.38-43
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• 2021

Purpose: We investigated the association between defoliant exposure and survival to discharge after out-of-hospital cardiac arrest. Methods: This is a retrospective case-control study based on the cardiopulmonary resuscitation (CPR) registry. The electronic medical records of out-of-hospital cardiac arrest victims from 6/9/2008 to 12/31/2016 were analyzed statistically. The case patients group had a history of defoliant exposure while the control group did not. Among the 401 victims studied, a total of 110 patients were male out-of-hospital cardiac arrest patients. Baseline characteristics and the parameters involved in cardiac arrest were analyzed and compared between the two groups after propensity score matching. The primary outcome was survival to discharge, and secondary outcomes were sustained return of spontaneous circulation (ROSC) and survival to admission. Results: After propensity score matching a total of 50 patients (case=25, control=25) were analyzed. Primary outcome (survival to discharge) was not significantly different between case and control groups [(OR, 1.759; 95% C.I., 0.491-6.309) and (OR, 1.842; 95% C.I., 0.515-6.593), respectively]. In the subgroup analysis, there were also no significant differences between the control group and subgroups in primary and secondary outcomes according to defoliant exposure severity. Conclusion: There is no statistically significant association between defoliant exposure and survival of out-of-hospital cardiac arrest.

• Imaging Science in Dentistry
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• 제30권1호
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• pp.71-79
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• 2000

Purpose : This study was aimed to evaluate the cell cycle arrest and apoptosis induction after irradiation and epidermal growth factor (EGF) treatment in three human epithelial tumor cell lines (A431, Siha, KB). Materials and Methods: Single irradiation of 2, 5 and 10 Gy was done on three cell lines with 5.38 Gy/min dose rate using Cs-137 irradiator at room temperature. Also, EGF of 10 ng/ml was added immediately after 10 Gy irradiation. Cell growth was evaluated by counting the living cell number using a hemocytometer at 1 day, 2 days, 3 days, 4 days and 5 days after irradiation. Cell cycle arrest and apoptosis induction were assayed with the flow cytometry at 8 hours, 12 hours, 1 day, 2 days, 3 days, 4 days and 5 days after irradiation. Results : Growth of irradiated three cell lines were inhibited in proportion to radiation dose. EGF treatment after irradiation showed various results according to cell lines. On all cell lines, G2 arrest was detected after 8 hours and maximized after 12 hours or 1 day. Amount of G2 arrest was positively dose dependent. However, EGF showed no significant change on G2 arrest. G2 arrest was recovered with time at 2 Gy and 5 Gy irradiation. However, at 10 Gy irradiation, G2 arrest was continued. Apoptosis was detected at 10 Gy irradiation. On EGF treated group after irradiation, A431 and Siha cell lines showed slightly increased apoptosis but there was no statistically significant difference. KB cell line showed no marked change of apoptosis induction. Conclusion : Irradiation effects on cell cycle arrest and apoptosis induction in three human epithelial tumor cell lines, however epidermal growth factor doesn't effect on.

• 대한임상독성학회지
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• 제3권2호
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• pp.93-98
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• 2005

Purpose: This study was to investigate the resuscitation outcomes and the clinical characteristics of non-traumatic drug-induced out-of-hospital cardiac arrest by analyzing data from a single institution's registry. Method: We conducted a retrospective study of 795 patients who came to the emergency department with non-traumatic drug-induced out-of-hospital cardiac arrest during the period $1991{\~}2004$. Only patients over 18 years of age were included. Clinical characteristics. variables associated with cardiac arrest, and data during resuscitation were obtained from our cardiac arrest database. Patients were divided into two groups: drug-induced cardiac arrest (drug group, n=33), and non drug-induced cardiac arrest (non-drug group, n=762). Results: Spontaneous circulation was restored in 23 ($72{\%}$) patients in the drug group and in 314 ($45{\%}$) patients in the non-drug group ($x^2=0.020$). The patients who discharged alive number were 46 ($6{\%}$) in the non-drug group and 0 ($0{\%}$) in the drug group ($x^2=0.005$). The witnessed arrest, the epinephrine doses, and total defibrillation energy were not different between two groups. Conclusion: The return of spontaneous circulation rate was higher in the drug group than the non-drug group. However the drug group was lower survival discharge rate than in the non-drug group.

• 디지털융복합연구
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• 제11권9호
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• pp.229-238
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• 2013

병원외 심정지는 오늘날 우리나라의 중대한 보건문제로서, 환자의 퇴원 시 생존율은 3.5%이며, 이 중 1%만이 신경학적 기능을 회복하는 것으로 나타났다. 이처럼 낮은 병원외 심정지 환자의 생존율을 높이기 위해서는 병원 도착 전 환자의 자발적 순환을 회복시키는 것이 매우 중요하다. 따라서 본 연구에서는 질병관리본부의 2009년도 심정지 의무기록 조사 자료를 활용하여 병원외 심정지 환자의 자발적 순환 회복률을 향상시킬 수 있는 요인들에 대한 심층 분석을 수행하였다. 심정지 환자의 자발적 순환 회복에 영향을 미치는 요인은 의사결정나무기법을 적용하여 분석하였으며, 그 결과 도착전 CPR여부, 병원 도착전 심정지 목격여부, 심정지시 활동, 과거력(암/심장질환/뇌졸중), 심정지 발생 장소, 병원전 일반인 CPR여부, 신고~현장 도착까지 걸린 시간, 연령 등이 중요한 요인으로 밝혀졌다. 이 요인들의 조합을 통해 의사결정나무모형으로 분류된 심정지 환자는 총 16개 유형이었으며, 그 중 유형 1의 특징을 갖는 집단의 자발적 순환 회복률(29.6%)이 가장 높게 나타났다. 더불어 비공공장소에서 심정지가 발생한 환자에게 일반인이 CPR을 시행하였을 경우, 심정지 환자의 자발적 순환 회복률이 향상된 것으로 보아 지역주민들에 대한 CPR교육이 중요함을 파악할 수 있었다.

• 생명과학회지
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• 제20권7호
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• pp.977-982
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• 2010

본 연구에서는 오미자에서 분리된 dibenzocyclooctadiene lignan의 일종인 gomisin A와 gomisin N에 대한 항암효능을 U937 인체혈구암세포를 대상으로 조사하였다. Gomisin N은 처리농도의 증가에 따라 U937 세포의 증식을 억제하였으나 동일조건에서 gomisin A는 세포독성 효과를 나타내지 못하였으며, gomisin N에 의한 U937 세포의 증식억제는 세포주기 G1 arrest 유발에 의한 것이었다. Gomisin N에 의한 G1 arrest는 cyclin E, cyclin-dependent kinase (Cdk) 2 및 Cdk4의 발현 억제와 Cdk inhibitor인 p16 (INK4A) 및 p21 (WAF1/CIP1)의 발현 증가와 연관성이 있었으나, gomisin A는 세포주기 인자들의 발현에 유의적인 변화를 유발하지 않았다. 또한 gomisin N은 retinoblastoma 단백질군인 pRB 및 p130의 인산화를 억제하였으며, 전사조절인자인 E2F 단백질들의 발현을 억제하였다. 본 연구의 결과에서 gomisin N에 의한 U937 세포의 증식억제는 세포주기 조절인자들의 발현 변화를 통한 G1 arrest 유발에 의한 것임을 알 수 있었으며, gomisin N은 암예방 및 항암활성 후보불질로서의 개발 가능성이 있음을 알 수 있었다.

• 의료법학
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• 제19권2호
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• pp.209-233
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• 2018

이 연구의 목적은 5년간(2012년~2016년) 응급실 도착 전 심정지 환자의 자발순환회복 여부를 파악하고, 이에 미치는 요인을 규명하기 위하여 시도하였다. 이 연구는 우리나라 전국을 대상으로 2012~2016년 '질병관리본부'에서 실시한 '급성심장정지조사 원시자료'를 주 자료로 사용하였다. 2012년부터 2016년 5년간의 국가 심장정지 조사 자료 중 심장정지 환자 136,212명을 분석 대상으로 하였다. 일반적 특성, 사회·인구학적 특성, 발생관련 특성에 따른 응급실 도착 전 자발순환 회복 여부를 파악하기 위해 교차분석을 하였고, 자발순환 회복 여부에 미치는 요인을 분석하고자 이분형 로지스틱 회귀분석을 실시하였다. 분석결과 응급실 도착 전 자발순환 회복 여부에 미치는 요인은 응급실 도착전 심폐소생술 지속 이송 여부, 응급실 도착 전 급성심장정지 목격 여부, 일반인 심폐소생술 시행 종류, 급성심장정지 발생 장소, 급성심장정지 발생 원인이었다(P<0.001, P<0.01). 그러므로, 심정지 환자의 자발순환 회복에 영향을 미치는 요인을 중심으로 체계적인 정부의 보건정책 시행과 대중적인 보건교육을 강화해야 할 것이다.

• 동의생리병리학회지
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• 제21권1호
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• pp.204-208
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• 2007

Chaga mushroom extract is well known as immune modulator and anti-cancer agent. However, the molecular mechanism by which Chaga exerts cell cycle arrest and apoptosis of cancer cells is poorly understood. In this study, we demonstrated anti-proliferative effects of Chaga extract on murine melanoma B16 cells. Chaga extract dose-dependently inhibited cell growth along with the arrest of G0/G1 phase and the induction of apoptotic cell death. Treatment with Chaga extract resulted in a decrease of cyclin E, cyclin D1, cdk 2, cdk 4 expression levels. Furthermore, in vivo inoculation study of B16 melanoma cells into Balb/c mice Chaga extract markedly suppressed the metastatic growth of tumor cells (6 folds, p<0.05,). These results indicate that Chaga mushroom extract induces apoptosis of B16 melanoma cells through arrest of G0/G1 phase in cell cycle.