TiO₂담지 세라믹 필터를 활용한 아세톤 제어에 관한 연구

윤정호,박덕신,이주열,조영민 한국대기환경학회 2003 한국대기환경학회지 Vol.19 No.1

HSP27 MODULATION OF IMPLANT- ASSOCIATED METAL ION CYTOTOXICITY OF OSTEOBLASTIC CELLS

윤정호,하동진,임재석,권종진,장현석,이의석,김대성,Yoon, Jung-Ho,Ha, Dong-Jin,Rim, Jae-Suk,Kwon, Jong-Jin,Jang, Hyon-Seok,Lee, Eui-Seok,Kim, Dae-Sung Korean Association of Maxillofacial Plastic and Re 2006 Maxillofacial Plastic Reconstructive Surgery Vol.28 No.2

Objectives: The extent of bone formation that occurs at the interface of metallic implants and bone is determined by the number and activity of osteoblastic cells. Stress proteins may be contributing determinants of cell viability in altered environments. Hsp27 is a small Mr hsp which is known as a molecular chaperone. Methods: To better understand how heat shock protein 27 contributes to endosseous implant - associated metal ions affects on osteoblastic cell viability, the effect of chromium and titanium ions were compared to effects of cadmium ions in the ROS17/2.8 osteoblastic cell line. Results: ROS17/2.8 osteoblastic cell line demonstrated ion - specific reductions in growth; reductions were significantly greater for cadmium than for chromium or titanium. Chromium impaired growth of cultures without altering cell viability measured using the MTT assay. A stable transformed cell line expressing additional hsp27(clone "A7") was resistant to the toxic effects of titanium and partially protected from cadmium toxicity. Conclusions: A role for hsp27 in protection of osteoblastic cells from metal ion toxicity is supported by the chromium - induced elevations in hsp27 abundance and the behavior of the A7 cell line in response to metal ions in culture. Similar biochemical responses to altered cellular environments may contribute to the fate of tissues adjacent to select metallic implants.

Repeated Cerebral Infarctions after Operation for Compound Depressed Skull Fracture: A Case Report

윤정호 대한응급의학회 2015 대한응급의학회지 Vol.26 No.1

Open skull fracture with a dirty and depressed lesion can lead to post-traumatic complications such as an embolic or hemorrhagic infarction, although the incidence is very rare. We report on one unpredictable case of repeated embolic infarctions after reconstruction for a patient with an open depressed skull fracture. A 51-year-old man presented with open crush wound at the right frontal lesion with drowsy mentality because of falling down. Computed tomography (CT) showed a 4×5 cm sized, compound comminuted depressed fracture at the frontal lesion involving the frontal sinus. We performed emergent surgical reduction and reconstruction by primary repair and pericranial graft. Postoperative CT and magnetic resonance image showed multiple low-density lesions at the right frontal and temporal subcortical area confirmed as multiple acute infarctions. One month after the operation, the patient complained of sudden headache, and the CT showed low and high density lesions at the right temporal area. Trans-femoral cerebral angiography showed delayed venous flow around the right superior and middle parietal cortex. The patient received conservative treatment, and, three months after treatment, the patient had recovered to close to normal neurology.

Salmonella typhi 에 의한 감염성 심내막염 1 예

윤정호,최재웅,신익균,안태훈,이성광,최윤영,장호열,윤형선,강영숙,최인석 대한내과학회 1996 대한내과학회지 Vol.51 No.4

We report a first case of subacute infective endocarditis due to S. typhi in Korea. The patient is a 58-year-old man and despite of antibiotic therapy, he presented with intermittent fever and chills for about 8 weeks after dental extraction in the Philippines. Salmonella typhi was isolated from blood culture and 2-D echocardiogram showed a 12㎜×4㎜ sized vegetation on ventricular surface of the aortic right coronary cusp. He was treated with intravenous cefotaxime for 24 days successfully and after discharge took oral ofloxacine for 4 weeks without any complication.

Pleiotrophin이 골수 줄기 세포의 부착 및 골형성에 미치는 효과에 대한 연구

윤정호,윤정주,장현석,임재석,이의석,김대성,권종진,Yoon, Jung-Ho,Eune, Jung-Ju,Jang, Hyon-Seok,Rim, Jae-Suk,Lee, Eui-Seok,Kim, Dae-Sung,Kwon, Jong-Jin 대한악안면성형재건외과학회 2006 Maxillofacial Plastic Reconstructive Surgery Vol.28 No.2

An area of current research is investigating the app1ication of human mesenchymal stem cells or hMSCs as a cell-based regenerative therapy. In order to achieve effective bone regeneration, appropriate matrices functioning as cell-carriers must be identified and optimized in terms of function, efficacy and biocompatibility. Two methods of approaching optimization of matrices are to facilitate adhesion of the donor hMSCs and furthermore to facilitate recruitment of host progenitor cells to osteoblastic differentiation. Pleiotrophin is an extracellular matrix protein that was first identified in developing rat brains and believed to be associated with developing neuronal pathways. A recent publication by Imai and colleagues demonstrated that transgenic mice with upregulated pleiotrophin expression developed a greater volume of cortical as well as cancellous bone. The proposed mechanism of action of pleiotrophin is demonstrated here. Through either environmental stresses and/or intracellular regulation, there is an increase in pleiotrophin production. The pleiotrophin is released extracellularly into areas requiring bone deposition. A receptor-mediated process recruits host osteoprogenitor cells into these areas. Therefore, the aim of our study was to investigate the osteoconductive properties of pleiotrophin. We wanted to determine if pleiotrophin coating facilitates cellular adhesion and furthermore if this has any effect on hMSCs derived bone formation in an animal model. The results showed a dose dependent response of cellular adhesion in fibronectin samples, and cellular adhesion was facilitated with increasing pleiotrophin concentrations. Histologic findings taken after 5 weeks implantation in SCID mouse showed no presence of bone formation with only a dense fibrous connective tissue. Possible explanations for the results of the osteogenesis assay include inappropriate cell loading.

알로덤 슬링술을 이용한 보형물 유방재건술; 임상경과 및 피막형성에 미치는 영향

윤정호,김영석,노태석,나동균 대한성형외과학회 2009 Archives of Plastic Surgery Vol.36 No.6

Purpose: Breast surgeons usually insert tissue expander or implant beneath the subpectoral - subglandular dual plane in breast reconstruction. But sometimes it happens unsatisfactory lower pole fullness, asymmetric inframammary fold and breast shape because there is implant migration due to the pectoralis major muscle contraction and gravity. To solve all the problem like these, we introduce implant breast reconstruction using AlloDerm®(LifeCell Corp., Branchburg, N.J.) sling. Methods: The AlloDerm® sling was used in 13 patients and 18 breasts for implant breast reconstruction. After mastectomy, costal and lower sternal insertion of pectoralis major muscle was detached. Rehydrated AlloDerm® was sutured to the chest wall and serratus anterior fascia at the level of inframammary fold downward and to lower border of the pectoralis major muscle upward like crescent shape with tension free technique after implant insertion into the subpectoral - subAlloDerm dual pocket. Results: We make satisfactory lower pole fullness, symmetric inframammary fold and breast shape. In conclusion, patients obtain relatively natural breast shape. There was no complication except one case of capsular contracture and one case of breast cellulitis. Conclusion: Implant breast reconstruction using AlloDerm® sling makes easy to get natural breast shape through satisfactory lower pole fullness, symmetric inframammary fold and implant positioning.

QUASI-INTERPOLATORY APPROXIMATION SCHEME FOR MULTIVARIATE SCATTERED DATA

윤정호 한국전산응용수학회 2011 Journal of applied mathematics & informatics Vol.29 No.3

The problem of approximation from a set of scattered data arises in a wide range of applied mathematics and scientific applications. In this study, we present a quasi-interpolatory approximation scheme for scattered data approximation problem, which reproduces a certain space of polynomials. The proposed scheme is local in the sense that for an evaluation point, the contribution of a data value to the approximating value is decreasing rapidly as the distance between two data points is increasing. The problem of approximation from a set of scattered data arises in a wide range of applied mathematics and scientific applications. In this study, we present a quasi-interpolatory approximation scheme for scattered data approximation problem, which reproduces a certain space of polynomials. The proposed scheme is local in the sense that for an evaluation point, the contribution of a data value to the approximating value is decreasing rapidly as the distance between two data points is increasing.

Sobolev type approximation order by scattered shifts of a radial basis function

윤정호 한국전산응용수학회 2007 Journal of applied mathematics & informatics Vol.23 No.1

An important approach towards solving the scattered data problem is by using radial basis functions. However, for a large class of smooth basis functions such as Gaussians, the existing theories guarantee the interpolant to approximate well only for a very small class of very smooth approximands, which is the so-called ‘native’ space. The approximands f need to be extremely smooth. Hence, the purpose of this paper is to study approximation by a scattered shifts of a radial basis functions. We provide error estimates on larger spaces, especially on the homogeneous Sobolev spaces.

도시형소공인 창업 및 지속성장을 위한 지원정책에관한 연구: 문래 기계․금속 집적지를 중심으로

윤정호,김영수,정연대 한국경영교육학회 2018 경영교육연구 Vol.33 No.6

[Purpose] The purpose of this study is to contribute to the development of the MMEs in charge of the nation’s basic industry by presenting cases of technology start-ups and policy suggestions for overcoming technology break crisis and maintaining sustainable growth through case studies on MMEs Support Policies. [Methodology] This study conducted a survey of 382 beneficiary companies of the Mullrae MMEs Specialized Support Center, which operated the Urban MMEs Support Project for the first time and the results were verified and analyzed through technical statistical analysis, frequency analysis and cross-section, etc. and case studies. [Findings] The study suggested (tailored) ways to support and nurture MMEs. First, among the development strategy of type stage presented by the Ministry or SMEs and Start-ups, stage is suggested that is suitable for the Mullae Mechane․Metals. Second, it introduced as a prototype production collaboration model and collaborative technology creation in step with Mullae Mechane․Metals’ core vision of a mid- to long-term development road map, ‘Transition to global prototyping sites.’ Third, it proposed supporting policies such as cooperative business sites, MMEs manufacturing technology innovation centers, and professional coordinator companies to enhance the competitiveness of the production infrastructure of the naturally formed Mullae Mechane․Metals. [Implications] Through these findings, we hope to contribute to the active development of research on the MMEs. As for practical implications, the center suggested the collaborative technology start-ups and proposed policies to enhance the competitiveness of MMEs. It aims to provide a theoretical background in the study of the entrepreneurship of MME sector in the future. [연구목적] 소공인의 지원정책에 대한 사례연구를 통하여 기술단절 위기 및 지속성장을위한 기술창업사례와 정책제언을 제시하여 국가의 기반산업을 담당하고 있는 소공인의발전에 기여하는데 본 연구의 목적이 있다. [연구방법] 본 연구는 도시형소공인 지원 사업을 최초로 운영한 문래지원센터의 수혜기업 382개사를 대상으로 설문조사를 실시하여, 그 결과를 기술통계분석, 빈도분석, 교차분석 등을 통하여 실증분석과 사례연구를 하였다. [연구결과] 이 연구를 통해 (맞춤형) 소공인 지원 및 육성방안을 제시하였다. 첫째, 중소벤처기업부의 ‘소공인 경쟁력 강화 방안’에서 제시한 유형 단계별 육성 전략 중 문래동집적지에 맞는 유형을 제시하였다. 둘째, 문래머시닝밸리의 중장기 발전로드맵의 핵심 비전인 ‘세계적인 시제품 제작 집적지로의 전환’과 보조를 맞추어 협업에 의한 새로운 기술창업 모델을 제시하였다. 셋째, 자연발생적으로 형성된 문래동 집적지의 생산인프라 경쟁력을 향상시키기 위하여 협동화사업장, 소공인 제조기술혁신센터, 전문코디네이터 기업등의 지원정책을 제언하였다. [연구의 시사점] 이러한 연구결과를 통하여 소공인 분야의 미미한 연구 자료에 기초가되어 소공인에 대한 연구가 활발하게 이루어지는데 기여할 수 있기를 바라며, 실무적 시사점으로는 소공인의 경쟁력 제고를 위한 협업기술창업 및 정책제언을 하였다. 향후 소공인 분야의 기업가정신을 연구하는데 있어서 이론적 배경을 제공하는 기틀이 되고자 한다.

근용부 누진 렌즈 설계가 조절 반응에 미치는 영향

윤정호,Christian Lappe 대한시과학회 2020 대한시과학회지 학술대회 Vol.2020 No.01