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이치훈,주민호,정철현,정성호,주석중,이재원,김준범 대한흉부외과학회 2014 Journal of Chest Surgery (J Chest Surg) Vol.47 No.3
Background: As hypertrophied myocardium predisposes the patient to decreased tolerance to ischemia and increased reperfusion injury, myocardial protection is of utmost importance in patients undergoing aortic valve replacement (AVR) for severe aortic valve stenosis (AS). Methods: Consecutive 314 patients (mean age, 62.5±10.8 years; 143 females) with severe AS undergoing isolated AVR were included. Postoperative myocardial injury (PMI) was defined as 1) maximum postoperative creatinine kinase isoenzyme MB or troponin-I levels ≥10 times of reference, 2) postoperative low cardiac output syndrome or episodes of ventricular arrhythmia, or 3) left ventricular ejection fraction of less than 55% and decrease in left ventricle (LV) ejection fraction of more than 20% of the baseline value. Results: There were 90 patients (28.7%) who developed PMI. There were five cases of early death (1.6%), all of whom had PMI. On multivariable analysis, the use of histidine-tryptophan-ketoglutarate (HTK) solution instead of blood cardioplegia (odds ratio [OR], 3.06; 95% confidence interval [CI], 1.63 to 5.77; p=0.001), greater LV mass (OR, 1.04; 95% CI, 1.01 to 1.07; p=0.007), and increased cardiac ischemic time (OR, 1.13; 95% CI, 1.05 to 1.22; p<0.001) were independent predictors for PMI. Patients who had PMI showed significantly inferior long-term survival than those without PMI (p=0.049). Conclusion: PMI occurred in a considerable proportion of patients undergoing AVR for severe AS and was associated with poor long-term survival. HTK cardioplegia, higher LV mass, and longer cardiac ischemic duration were suggested as predictors of myocardial injury.
200㎏급 틸트로터무인기 풍동시험을 위한 동체 및 지지용 어댑터 전산유동해석
이치훈,김유신,최성욱 한국항공우주학회 2012 한국항공우주학회 학술발표회 논문집 Vol.2012 No.11
본 연구에서는 KARI 중형 아음속 풍동시험에서 수행한 200㎏급 틸트로터무인기의 공력데이터 보정을 위한 동체 및 지지용 어댑터에 대한 전산유동해석을 수행하였다. 동체 및 어댑터 개별형상과 동체-어댑터 결합형상에 대한 유동해석을 각각 수행하고 결과를 비교하여 공기역학적 간섭효과 및 공력데이터 변화를 파악하였다. 표면 및 공간 유동 가시화(Streamline)를 통하여 동체의 국부적인 박리영역을 확인하였으며 결과를 분석하였다. In this study the computational flow analysis around fuselage and support adaptors of the 200㎏-class tiltrotor UAV was conducted to correct aerodynamic data obtained from the windtunnel test in KARI LSWT. Flow calculations for the isolated and the combined configurations of fuselage and adaptors were carried out respectively and aerodynamic interferences between two components were investigated. The local flow behavior around the junction region of fuselage and adaptors was analyzed from the computational flow visualization.