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임플란트 주위 골 결손 부위에 Choukroun's Platelet-rich-fibrin와 실크 분말 복합 이식재 사용
장은식,이형석,이희성,이희종,박기유,박영욱,윤연진,홍순민,박준우,Jang, Eun-Sik,Lee, Hyung-Seok,Lee, Hee-Sung,Lee, Hee-Jong,Park, Ki-Yu,Park, Young-Wook,Yoon, Youn-Jin,Hong, Soon-Min,Park, Jun-Woo 대한악안면성형재건외과학회 2011 Maxillofacial Plastic Reconstructive Surgery Vol.33 No.2
Purpose: Choukroun's platelet-rich-fibrin (PRF) is composed of platelets, white blood cells and fibrin matrix. It does not induce enough bone formation by itself but it can improve bone formation with calcium. Silk fibroin does not cause inflammatory reactions because it is bio-compatible and degradable. The purpose of this study was to exam the bone formation when a combination of Choukroun's PRF and silk fibroin was used. Methods: In this study, cell reactions to silk powder with differing molecular weights was first tested to select the appropriate silk powder. Then we applied these bone graft materials on defects of skull and in a peri-implant bony defect model in New Zealand rabbits. The results between the experimental and control s (non-grafted) group were analyzed. Results: The small sized silk fibroin powder showed increased cellular proliferation for bone-regeneration. There was no statistically significant difference between the experimental group and the control group at 6 weeks, but more new bone formation was observed in the combination graft group at 12 weeks (P<0.05). And in the dental implant model, the combination bone graft group showed much improved torque test results, which was statistically significant. Histomorphometric analysis showed more regenerated cortical bone and a higher mean bone to implant in the experimental group. Both were statistically significant. Conclusion: The combination graft of Choukroun's platelet-rich-fibrin (PRF) and silk fibroin powder can successfully restore the bony defects in a skull defected model and a peri-implant bony defects model.
장은식(Eun-sik Jang),조규종(Kyu-jong Cho),이명규(Myung-gyu Lee),Chen-si 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
Refrigerator Door is the non-symmetric structure consist of Stainless steel plate, Urethane Foam, ABS and Plastic injection product. When the manufacturing process of refrigerator door, partial constriction caused deformation of Stainless steel plate in the process of polymerization and cooling after injection of Urethane between Stainless steel plate and ABS. This is the displacement of cooling & contraction process from end of Urethane polymerization (12 ℃) to ambient temperature (20℃), and it can be recognizable displacement about 0.2 - 0.3㎜. So, We studied that grasp the main factor of Refrigerator Door displacement and show the scheme of thermal strain minimization.
장은식(Eun-sik Jang),이무형(Mu-hyoung Lee),김성준(Sung-jun Kim) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
Structural integrity evaluation is important item in the aircraft certification. Recently, it is designed for limit load, material weakness about fatigue and corrosion, damage by bird strike in flight to evaluate structural integrity of aircraft. And static/fatigue analysis are performed to secure integrity, it was verified by static and fatigue tests. In the present study, finite element analysis are performed to pick out load cases in flight occurrence, and secure margin of safety to evaluate structural integrity of small aircraft tail unit. Strain gages are choose and attached from result of finite element analysis, displacement sensors are attached to measure displacement under test loads. Finally, structural integrity is evaluated from the results of FE analysis and full scale static test.
심혜영,정다운,채창훈,이영,장은식,최미라,홍순민,박준우,Sim, Hye-Young,Jung, Da-Un,Chae, Chang-Hoon,Lee, Young,Jang, Eun-Sik,Choi, Mee-Ra,Hong, Soon-Min,Park, Jun-Woo 대한악안면성형재건외과학회 2010 Maxillofacial Plastic Reconstructive Surgery Vol.32 No.1
The vascular changes in periodontal tissues cause local hypoxia which seems to affect the periodontal tissue cells. Abrupt changes in oxygen availability within the periodontium have been suggested to have a regulatory role in alveolar bone remodeling during tooth movement, bone growth or fracture healing. The purpose of this study was to study the effects of hypoxia on formation of osteoclast responsible for bone resorption, in vitro. Primary mouse bone marrow cells were cultured in normoxic (20% $O_2$) and hypoxic (1% $O_2$) conditions and assayed for cellular proliferation. The results obtained were as follows : 1. Reducing oxygen tension increased the formation of multinucleated osteoclasts. 2. Hypoxic stimulus increased the size of mature osteoclasts.