27 research outputs found
양 모델에서 삼첨판막륜 축소 성형술 시행 시 부위별 고정 봉합 강도와 심장 수축 주기에 따른 부위별 봉합 강도의 측정
Get PDF학위논문(박사) -- 서울대학교대학원 : 의과대학 의학과, 2021.8. 황호영.Objective
This study was conducted to measure suture tie-down forces and evaluate cyclic contractile forces (CCFs) in beating hearts after undersized 3-dimensional (3D) rigid-ring tricuspid valve annuloplasty (TAP).
Methods
Eight force transducers were attached to the 3D rigid TAP ring. Segment 1 to 8 were attached from the mid-septal to anterior-septal commissural area in a counterclockwise order. Two-sizes-down TAPs were performed in 6 sheep. Tie-down forces and CCF were recorded an analysed at the 8 annular segments and at 3 levels of peak right ventricular pressure (RVP: 30,50 and 70mmHg).
Results
The overall average tie-down forces and CCF were 4.34 ± 2.26 newtons (N) and 0.23 ± 0.09 N, respectively. The CCF at an RVP of 30mmHg were higher at 3 commissural areas (segment 3, 5 and 8) than at the other segments. The increases in th CCF following changes in the RVP were statistically significant only at the 3 commissural areas (P = 0.012). However, mean CCFs remained low at all annular positions (ranges of average CCF = 0.06-0.46 N).
Conclusions
The risk of suture dehiscence after down-sized 3D rigid-ring TAP might be minimal because the absolute forces remained low in all annular positions even in the condition of high RVP. However, careful suturing in the septal annular area and commissures in necessary to prevent an annular tear during a down-sized 3D ring-ring TAP.목적
삼첨판막륜 축소 성형술 시행 시 고정 봉합 강도와 심장 수축 주기에 따른 부위별 봉합 강도의 측정을 위해 연구를 시행하였다.
방법
8개의 변환기를 3차원 삼첨판막 성형 링에 부착하였다. 1구간에서 8구간은 삼첨판막의 중격 판막륜 중간에서 시작하여 앞-중격 판막 연결부위까지 반 시계방향으로 부착하였다. 총 6마리의 양에 2크기 축소 링 삼첨판막륜 성형술을 시행하였다. 링의 8개 구간에서의 고정 봉합 강도와 우심실 압력 30, 50, 70mmHg에서의 심장 수축 주기에 따른 부위별 봉합 강도를 기록하고 분석하였다.
결과
고정 봉합 강도와 심장 수축 주기에 따른 봉합 강도는 3.34 ± 2.26 N, 0.23 ± 0.09 N 이었다. 심장 수축 주기에 따른 봉합 강도는 우심실 압력 30 mmHg일 때 각 판막의 연결 부위에서 다른 부위 보다 높았다(3, 5, 8 구간). 우심실 압력이 높아질 때 심장 수축 주기에 따른 봉합 강도는 각 판막의 연결 부위에서만 증가하였다 (P=0.012). 그러나 심장 수축 주기에 따른 봉합 강도의 평균은 모든 부위에서 낮았다 (평균 0.06-0.46 N).
결론
삼첨판막륜 축소 성형술 이후 링 열개의 위험도는 모든 부위에서의 절대적인 힘의 크기가 높은 우심실 압력에서도 작아서 낮을 수 있다. 그러나 삼첨판막륜 축소 성형술 시행 시 판막륜 찢어짐을 예방하기 위해 중격 판막 륜 부위와 각 판막의 연결 부위를 주의해서 봉합 할 필요가 있다.Chapter 1. Introduction 1
Chapter 2. Body 3
Chapter 3. Conclusion 28
Bibliography 29
Abstract in Korean 37박
예산제약 하에서의 Contest Mechanism에 대한 연구
Get PDF학위논문(석사) -- 서울대학교대학원 : 사회과학대학 경제학부, 2022.2. 김진우.In this paper, I analyzed how inserting of budget constraint assumption makes difference with the results of previous studies on contest mechanism design problems such as optimal contest mechanism design and affirmative action design. When there are some budget-constrained agents, mechanism designers have to think over not only the best way to balance gains (desirable allocation) and losses (wasteful cost) from the contest but also the best way to balance allocation of budget-constrained agents and budget-free agents. Compared to assortative matching mechanism, random matching mechanism and coarse matching mechanism are more likely to balance allocation of budget-constrained agents and budget-free agents well. Since random matching mechanism and coarse matching mechanism make participants waste less resources in signaling, they relieve some problems caused by budget constraints. When affirmative action is implemented, therefore, random matching mechanism and coarse
matching mechanism allow agents with budget constraint problems to win for open seats.
Consequently, more minority people are expected to achieve school seats under random or
coarse matching mechanism.1. Introduction - 1
2. Literature Review - 3
3. The economy
3.1. Model - 4
3.2. Benchmark Equilibrium - 5
3.3. Reserve Seat Design - 8
4. Minimum Standard Mechanism - 10
5. Conclusion - 14
appendix - 16석
Bacterial Expression and Purification of Caspase-Activated DNase and its inhibitor ICAD for X-Ray Crystallographic Study
No full textMaste
