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미세중력 모사 환경 하에서 중간엽 줄기세포 증식에 관한 실험적 연구
김희락(Hee Rak Kim),윤석환(Seok Hwan Yun),홍규식(Gyu Sik Hong),조정환(Jeong Hwan Cho),심진형(Jin Hyung Shim),김택영(Taig Young Kim) 대한기계학회 2020 大韓機械學會論文集B Vol.44 No.1
중력의 방향을 분산시키는 RPM(Random Positioning Machine)과 bio-printing 된 3D scaffold를 이용하여, 우주의 미세중력을 모사한 환경하에서 중간엽 줄기세포(MSC: Mesenchymal Stem Cells)의 3차원 증식실험을 수행하고, 중력장에서 배양한 동일한 대조군 실험 결과와 정량적으로 비교 및 분석하였다. 자체제작한 RPM 배양기와 3D scaffold의 신뢰성과 안정성도 선행 실험을 통하여 검증하였다. RPM 배양기의 증식 세포는 중력장 하에서 배양된 대조군에 비하여 3차원적 증식이 뚜렷이 발현되었음을 SEM 사진을 통하여 확인하였다. RPM 회전에 따른 세포 안착의 불안정성 때문에 초기 생착률이 낮지만 3차원 배양에 따른 증식률 증가로 인하여 day 4.5에서 증식 세포 수의 역전이 발생하고, 결과적으로 RPM 작동 하에서 증식이 더 활발함을 정량적으로 확인하였다. 이와 같은 연구 결과로부터 RPM에 의한 미세중력 모사 환경이 MSC 증식에 긍정적인 역할을 함을 알 수 있다. Using random positioning machine (RPM), which disperses the gravity direction, and bio-printed 3D scaffold, the experiments on three-dimensional proliferation of mesenchymal stem cells (MSC) were performed under the simulated microgravity environment, and the results were quantitatively compared with the control groups cultivated in the Earth gravity. Reliability and stability of the RPM incubator and the 3D scaffold, manufactured inhouse, were also experimentally verified prior to the main experiments. The cells cultivated in RPM were confirmed through SEM photos to obviously show three-dimensional proliferation compared to the control group incubated under the gravitational field. The RPM rotations made cell settlements unstable, and as a result, the living cell numbers in early phase were small. However, the rate of proliferation was higher in simulated microgravity, and the living cell numbers overtook that of control group in day 4.5 resulting from more active proliferation in RPM incubator. From the present study, it can be confirmed that simulated micro gravity environment through RPM rotation plays a positive role in the proliferation of MSC.
Coal Tar Pitch-Asphaltene을 Binder로 한 Carbon-Materials 제조 및 物性에 관한 硏究
김희락,오재원 大田工業大學 1990 한밭대학교 논문집 Vol.7 No.2
The results of the experiment of properties of carbon-materials in which we used asphaltene extracted from coal tar pitch as binder are as follows : When asphaltene extracted from coal tar pitch was carbonized to 900℃ in nitrogen atmosphere, the carbon yield of 65% was seen. When green composite filled up with 50% graphite was carbonized, the linear shrinkage rate was about 2.1%. When specimen was made from extrusion molding more than hot-press molding, the result was appeared with the higher flexural strength.