http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Cost-Aware Adaptive Design of Experiment with Nonstationary Surrogate Model for Wind Tunnel Testing
최의환,김준홍,안재명 한국항공우주학회 2020 International Journal of Aeronautical and Space Sc Vol.21 No.3
This paper proposes a novel adaptive design of experiment (ADoE) framework with cost-aware sampling strategy and nonstationary surrogate model for efficient wind tunnel testing. The ADoE framework, which is based on the Gaussian process, can effectively reduce the required number of an experiment while maintaining its accuracy. The proposed cost-aware sampling strategy augments the framework by selecting cost-efficient experiment points and the nonstationary surrogate model effectively reflects the nonlinearity of the system on the response surface model. The efficacy of the proposed framework has been validated through a virtual experiment using an actual high angle-of-attack wind tunnel test dataset, which is highly nonlinear.
Maintenance of genome integrity and active homologous recombination in embryonic stem cells
최의환,윤서빈,Koh Young Eun,서영진,김근필 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-
Embryonic stem cells (ESCs) possess specific gene expression patterns that confer the ability to proliferate indefinitely and enable pluripotency, which allows ESCs to differentiate into diverse cell types in response to developmental signals. Compared to differentiated cells, ESCs harbor an elevated level of homologous recombination (HR)-related proteins and exhibit exceptional cell cycle control, characterized by a high proliferation rate and a prolonged S phase. HR is involved in several aspects of chromosome maintenance. For instance, HR repairs impaired chromosomes and prevents the collapse of DNA replication forks during cell proliferation. Thus, HR is essential for the maintenance of genomic integrity and prevents cellular dysregulation and lethal events. In addition, abundant HR proteins in the prolonged S phase can efficiently protect ESCs from external damages and protect against genomic instability caused by DNA breaks, facilitating rapid and accurate DNA break repair following chromosome duplication. The maintenance of genome integrity is key to preserving the functions of ESCs and reducing the risks of cancer development, cell cycle arrest, and abnormal replication. Here, we review the fundamental links between the stem cell-specific HR process and DNA damage response as well as the different strategies employed by ESCs to maintain genomic integrity.
Aloe, Gelfoam, Plaster가 골결손부의 신생골 형성에 미치는 영향에 관한 실험적 연구
최의환,김수관,Choi Eui-Hwan,Kim Su-Gwan 대한영상치의학회 1999 Imaging Science in Dentistry Vol.29 No.2
Purpose: This study was to evaluate the effects of Aloe. Gelfoam. and Plaster of Paris on bone healing. Materials and Methods: Four experimental defects were created for placement of the three materials in the right femur of dogs. One defect served as an empty control site. The evaluation was performed at 1-. 6-. and 12-weeks by light microscopy and radiographs. Results: Radiographic and histologic examinations showed new bone formation in the presence of Aloe, Gelfoam. and Plaster of Paris and similar bone healing reactions. Conclusion: On the basis of these findings, it was concluded that Aloe, Gelfoam. and Plaster of Paris may be adequate agents for use in bone procurement.
최의환,윤서빈,한윤수,김근필 한국분자세포생물학회 2017 Molecules and cells Vol.40 No.2
Homologous recombination (HR) is necessary for maintenance of genomic integrity and prevention of various mutations in tumor suppressor genes and proto-oncogenes. Rad51 and Rad54 are key HR factors that cope with replication stress and DNA breaks in eukaryotes. Rad51 binds to single-stranded DNA (ssDNA) to form the presynaptic filament that promotes a homology search and DNA strand exchange, and Rad54 stimulates the strand-pairing function of Rad51. Here, we studied the molecular dynamics of Rad51 and Rad54 during the cell cycle of HeLa cells. These cells constitutively express Rad51 and Rad54 throughout the entire cell cycle, and the formation of foci immediately increased in response to various types of DNA damage and replication stress, except for caffeine, which suppressed the Rad51-dependent HR pathway. Depletion of Rad51 caused severe defects in re-sponse to postreplicative stress. Accordingly, HeLa cells were arrested at the G2–M transition although a small amount of Rad51 was steadily maintained in HeLa cells. Our results suggest that cell cycle progression and proliferation of HeLa cells can be tightly controlled by the abundance of HR proteins, which are essential for the rapid response to postreplicative stress and DNA damage stress.