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탈단백 우골을 이용한 상악동 거상술 후 즉시 임플란트 식립에 대한 임상적 평가
김현국,김진욱,김진수,Kim, Hyun-Kuk,Kim, Jin-Wook,Kim, Chin-Soo 대한악안면성형재건외과학회 2011 Maxillofacial Plastic Reconstructive Surgery Vol.33 No.3
Purpose: Placement of endosseous implants in the atrophic maxilla is often restricted because of the lack of supporting bone. In this article, augmentation of the maxillary sinus floor with deproteinized bovine bone to enable insertion of endosseous implants is described. The technique is aimed at providing a cortical layer on top of the graft to ensure a reliable seal of the maxillary sinus and to achieve optimal stability of the bone graft in case of simultaneously placement of dental implants. Methods: The procedure was used in 200 patients (839 implants), using deproteinized bovine bone. The mean follow-up was 28.5 months. No inflammation of the bone grafts nor of the maxillary sinus occurred. The patients received implant supported overdentures or bone-anchored bridges. Results: The survival rate of implant restoration of this study was 97.6%. The total average of marginal bone loss in radiographs was $0.20{\pm}0.38$ mm. Insufficient primary stability, bony quality, and infection were thought to be associated factors in the failed cases. Conclusion: This study documented that deproteinized bovine bone, when used as a grafting material for augmentation of the sinus floor, may lead to proper osseointegration of a endosseous implant.
힐버트 공간 채움 곡선을 이용한 공간 질의 결과 크기 추정
김현국,황환규 강원대학교 정보통신연구소 2003 정보통신논문지 Vol.7 No.-
Spatial query processing in large spatial databases costs very much. Therefore the query result size estimation is required to reduce the cost for the optimized query plan. To this end, we estimate the query result size from the summary data which is obtained by approximating the distribution and characteristics of the spatial data. new spatial partitioning technique based on the Hilbert space filling curve combined with the Equi-Count In this paper, we examine the several existing spatial partitioning techniques such as Equi-Area and Equi-Count partitioning, and R-tree indexing partitioning. We propose apartitioning technique. A variety of experiments demonstarate that the proposed partitioning technique is superior to the existing ones.
김현국,신규식,황순웅,한창수 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
In this study, a link length determination method for the reduction of the performance deviation in the whole workspace of themanipulator was proposed. The structural length index (SLI), condition number (CN), and global conditioning index (GCI) wereselected as performance indices for link length determination. To evaluate deviation, the CN was calculated in the whole workspace,and then the data was used to calculate the coefficient of variation. The Taguchi method was used to decrease the time of optimizationfor the whole workspace, and Grey relational analysis was performed to convert the values for multiple objective functions to onevalue defined by the Grey relational grade. Furthermore, the effects of the design factors on the objective function were analyzedthrough analysis of variance. Optimization was performed twice for each objective function to compare the result of the consideringthe performance deviation and the result of the considering the performance mean. Each objective function consists of (A) the SLIand the coefficient of variation of the CN and (B) the SLI and GCI. The validity of the proposed method was verified by comparingthe results of (A) and (B) for performance deviation, mean and the rate of valid workspace.
김현국,김한별,이주명,김성수,배인호,박대성,박준규,심재원,나주영,이민영,김중선,심두선,홍영준,남창욱,도준형,박종한,구본권,김선욱,임경섭,정명호 대한의학회 2019 Journal of Korean medical science Vol.34 No.19
Background: Patients with acute myocardial infarction (AMI) have worse clinical outcomes than those with stable coronary artery disease despite revascularization. Non-culprit lesions of AMI also involve more adverse cardiovascular events. This study aimed to investigate the influence of AMI on endothelial function, neointimal progression, and inflammation in target and non-target vessels. Methods: In castrated male pigs, AMI was induced by balloon occlusion and reperfusion into the left anterior descending artery (LAD). Everolimus-eluting stents (EES) were implanted in the LAD and left circumflex (LCX) artery 2 days after AMI induction. In the control group, EES were implanted in the LAD and LCX in a similar fashion without AMI induction. Endothelial function was assessed using acetylcholine infusion before enrollment, after the AMI or sham operation, and at 1 month follow-up. A histological examination was conducted 1 month after stenting. Results: A total of 10 pigs implanted with 20 EES in the LAD and LCX were included. Significant paradoxical vasoconstriction was assessed after acetylcholine challenge in the AMI group compared with the control group. In the histologic analysis, the AMI group showed a larger neointimal area and larger area of stenosis than the control group after EES implantation. Peri-strut inflammation and fibrin formation were significant in the AMI group without differences in injury score. The non-target vessel of the AMI also showed similar findings to the target vessel compared with the control group. Conclusion: In the pig model, AMI events induced endothelial dysfunction, inflammation, and neointimal progression in the target and non-target vessels.