학술발표 : 어업기술 분야 / 포스터발표 ; 저예강 어구의 발줄 및 저질의 종류에 력학적 특성

신정욱,이주희,권병국 한국국제경제학회 2001 한국국제경제학회 학술대회발표 논문집 Vol.2011 No.3

대퇴골두 무혈성 괴사증의 수술적 기법들에 대한 생체역학적 변수해석 ( A Parametrical Biomechanical Analysis pf Surgical Procedures for Osteonecrosis of the Femoral Head )

신정욱,이성재,김정성,김용식 대한기계학회 1997 대한기계학회 춘추학술대회 Vol.- No.-

인간 각막 표면의 변형에 대한 3차원적 측정 ( Three Dimensional Measurement of Human Corneal Surface Deformation )

신정욱,R. P. Vito,김정성,이성재 대한기계학회 1996 대한기계학회 춘추학술대회 Vol.- No.-

바이오리액터(Bioreactor)시스템을 이용한 조직 공학

신정욱,허수진,Sin, Jeong-Uk,Heo, Su-Jin 재료연구소 2006 機械와 材料 Vol.18 No.4

Elevated CO2 and Temperature Effects on the Incidence of Four Major Chili Pepper Diseases

신정욱,윤성철 한국식물병리학회 2010 Plant Pathology Journal Vol.26 No.2

Four major diseases of chili pepper including two fungal diseases, anthracnose (Colletotrichum acutatum)and Phytophthora blight (Phytophthora capsici), and two bacterial diseases, bacterial wilt (Ralstonia solanacearum)and bacterial spot (Xanthomonas campestris pv. vesicatoria), were investigated under future climatechange condition treatments in growth chambers. Treatments with elevated CO2 and temperature were maintained at 720 ppm±20 ppm CO2 and 30oC±0.5oC,whereas ambient conditions were maintained at 420ppm±20 ppm CO2 and 25oC±0.5oC. Pepper seedlings or fruits were infected with each pathogen, and then the disease progress was evaluated in the growth chambers. According to paired t-test analyses, bacterial wilt and spot diseases significantly increased by 24% ( p=0.008)and 25% ( p=0.016), respectively, with elevated CO2 and temperature conditions. On the other hand, neither Phytophthora blight ( p=0.906) nor anthracnose ( p=0.125) was statistically significant. The elevated CO2 and temperature accelerated the progress of bacterial wilt by two days and bacterial spot by one day compared to the ambient treatment. Temperature regime studies of the diseases without changes in CO2 confirmed that the accelerated bacterial disease progress was mainly due to the increased temperature rather than the elevated CO2conditions.

백서 두개골 결손부에 이식된 PDGF 처리 동종탈회 동결 건조골의 골치유에 대한 실험적 연구

신정욱 대한악안면성형재건외과학회 2000 Maxillofacial Plastic Reconstructive Surgery Vol.22 No.6

After 1668, Van Meek'ren report the first case of bone graft, bone graft is one of the common procedures that Oral and Maxillofacial surgeons do routinely. The more bone grafting is performed, the more interest about bone graft materials and its substitutes, much study have been performed for bone graft materials and its substitutes for more better result such as lower antigenicity, more biocompatibility, and more osteogenic potential. Many kinds of growth factors influenced in grafted bone healing and regeneration. Growth factors are naturally synthesized polypeptide, stimulates much cellular activities, and work as a powerful biological mediator affecting cellular migration, mitosis, and matrix synthesis. Platelet Derived Growth Factor (PDGF), Epithelial Growth Factor (EGF), Transforming Growth Factor (TGF), Insulinelike Growth Factor (IGF) are well known representative growth factors. PDGF accelerate DNA synthesis of fibroblast, Lynch repoted that combination with IGF-1 increase osteogenesis in vivo study, Hyun reported that simultatious DFDB graft with PDGF-BB increase total osteogenesis and accelerates healing process, too. But, Clinical usages of PDGF have much disturbance such as stability, safety, and unreliable pharmachokinetics. Arm et al reported, osteogenesis with the controlled release PDGF carrid by porous hydroxyappatite in vivo and vitro studies. If PDGF-BB treated DFDB which commonly are used clinically, are implated, it may be get superior results and easier handling by controlled release This study was designed to find out the effect of PDGF treated BFDB on healing. We made calvarial defects with 6mm diameter in 30 rats (Negative control group), and filled 15mg allogenic DFDB into the calvarial defect with 6mm diameter in 30 rats (Control group), and filled 15mg PDGF treated allogenic DFDB (in saturation of 200ng PDGF-BB/15mg DFDB) into the calvarial defect with 6mm diameter in 30 rats (Experimental group), then sacrificed them and removed the previously- operated area involving the whole defect at the date of postoperative 1 week, 2 weeks, 3 weeks, 6 weeks, 8 weeks, 12 weeks. The removed specimens were stained with H&E then, histologic analysis under the light microscope and mechanical analysis via punch-out test was carried out. So, we got the results followed by 1) In every group of calvarial defect, the amount of new bone formation was increased as the time being. 2) In Experimental group and Control group, bridging images connecting both cutting edges of calvarial defects were observed. but in Negative control group, bridging images connecting both cutting edges of calvarial defects were not observed until 6 weeks after operation. 3) The largest amount of newly formed bone was observed in Experimental group, less in Control group and the least in Negative control group after experiment. In the mechanical analysis, there is statically significant increase of bony strength between Control and Experimental group, at 1 week, 2 weeks, 3 weeks, but there is no statically significant difference among the groups at 6 weeks, 8 weeks, 12 weeks. though the increasing pattern were observed. From the above results, it is suggested that PDGF treated DFDB promote more new bone formation transplanted in bone defect area and allogenic DFDB can be a carrier of PDGF in delivery system.

A Monte Carlo Simulation Study of a Therapeutic Proton Beam Delivery System Using the Geant4 Code

신정욱,심현하,곽정원,김동욱,박성용,조관호,이세병,Shin, Jungwook,Shim, Hyunha,Kwak, Jungwon,Kim, Dongwook,Park, Sungyong,Cho, Kwan Ho,Lee, Se Byeong Korean Society of Medical Physics 2007 의학물리 Vol.18 No.4

국립암센터에 설치된 양성자 치료기의 빔 전달 시스템에 대하여 Geant4 코드를 이용하여 몬테카를로 전산모사를 수행하였고, 선량검증 도구로써의 이용 가능성에 대하여 연구하였다. 몬테카를로 기술을 기반으로 하는 선량계산은 물질내의 선량분포를 이해하는 데 가장 정확한 방법으로 알려져 있다 외부조사 방사선치료에 있어서 이 방법의 장점을 극대화 하기 위해서는, 빔이 지나가는 곳에 놓여진 노즐 구성요소들의 정확한 모델링과 더불어 초기빔 특성파악은 무엇보다 중요하다. 국립암센터에 설치된 양성자 치료기는 총 3가지 형태-double/single scattering, uniform scanning and pencil-beam scanning-로 치료빔을 조사할 수 있으며, 본 연구진은 Geant4.8.2 코드를 기반으로 double/single scattering 모드를 구성하는 모든 노즐구성요소들에 대하여 모델링 하였다. 특정 치료감이에 대하여 실험치와 일치하는 전산모사의 결과를 얻었다 본 기관에 설치된 양성자치료기에 대한 몬테카를로 전산모사에 대한 기반을 성공적으로 구축하였고, 치료빔에 대하여 정밀한 선량측정에 이용할 수 있다. 치료빔의 전 에너지 영역에 걸쳐 추가적인 커미셔닝을 수행할 것이다. We studied a Monte Carlo simulation of the proton beam delivery system at the National Cancer Center (NCC) using the Geant4 Monte Carlo toolkit and tested its feasibility as a dose verification framework. The Monte Carlo technique for dose calculation methodology has been recognized as the most accurate way for understanding the dose distribution in given materials. In order to take advantage of this methodology for application to external-beam radiotherapy, a precise modeling of the nozzle elements along with the beam delivery path and correct initial beam characteristics are mandatory. Among three different treatment modes, double/single-scattering, uniform scanning and pencil beam scanning, we have modeled and simulated the double-scattering mode for the nozzle elements, including all components and varying the time and space with the Geant4.8.2 Monte Carlo code. We have obtained simulation data that showed an excellent correlation to the measured dose distributions at a specific treatment depth. We successfully set up the Monte Carlo simulation platform for the NCC proton therapy facility. It can be adapted to the precise dosimetry for therapeutic proton beam use at the NCC. Additional Monte Carlo work for the full proton beam energy range can be performed.

유한요소법과 동물실험을 통한 난시교정술의 고찰 및 개발

신정욱,한태원,김수향,김재호,이성재,박효순,Sin, Jeong-Uk,Han, Tae-Won,Kim, Su-Hyang,Kim, Jae-Ho,Lee, Seong-Jae,Park, Hyo-Sun 대한의용생체공학회 1999 의공학회지 Vol.20 No.1

본 연구는 동물실험과 유한요소법을 병행하여 난시교정을 위한 각막 절개 수술시 관련되는 다양한 인자의 변화가 수술 결과에 미치는 영향을 분석하고자함에 그 목적이 있다. 난시 교정술 중 각막절개에 의한 방법으로는 각막의 정점으로부터 일정거리에서 호선(arcuate)으로 절개하는 것이 일반적이나 본 연구에서는 직선(straight), 그리고 역호선(inverse arcuate) 절개방법도 시도하여 그 결과를 역학적으로 분석하였다. 연구결과 각막절개를 이용한 난시교정은 arcuate 방법이 가장 예측 가능하였으며, 수술의 효과는 각막의 정점과 가장자리 중간위치에서의 절개가 가장 효과적인 것이 실험과 유한요소에서 공히 검증되었다. 이를 바탕으로 유한요소 방법으로 arcuate 절개술에서 절개길이를 변화시킨 결과 90도 만큼의 절개가 120도 혹은 150도까지 절개한 것보다 더 큰 굴절률 변화를 보여주어 최대 굴절률 변화를 위한 절개 각도는 90도라는 결론을 얻었다. 하지만 시술결과 각막의 점탄성 성질과 자가치유 효과에 의한 수술효과는 시간이 지날수록 감소되는 경향을 보여 앞으로의 연구는 점탄성의 성질이 고려되어야 할 것으로 사료된다. The purpose of this study is to investigate the effects of various factors in keratotomy for astigmatism correction on surgical outcomes by finite element method as well as animal experiments. Three kinds of surgical techniques were mechanically investigated : arcuate, straight, and inverse arcuate keratotomy. Among the three techniques the arcuate keratotomy is the most popular one while the other two techniques are being investigated in this area. The arcuate keratotomy was found to be more controllable and effective in reducing the refractive power than the others. In arcuate keratotomy it was found most effective when the incision was located in the middle position between the apex and the edge of the cornea from the results of experiment as well as finite element study. Regarding to the range of the corneal incision in arcuate keratotomy, the incision angle of 90$^{\circ}$ was found th be most effective in reducing refractive power than other angles even it was incised up to 150$^{\circ}$. Therefore, it was concluded that 90$^{\circ}$ of incision angle results in the largest decrease in refractive power in arcuate keratotomy. However, other important findings were that the effect of the surgery decreased with time so the visco-effect of the cornea and auto-healing process. Therefore, these factors should be considered in future studies.

Th09교육2 : 기계공학과에서 의공학 강의(예)

신정욱 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11

Effects of Mechanical Stimuli on the Cell Proliferation and Collagen Production on the Micropatterned Substrate

신정욱,박수아,김정락,신지원 대한의생명과학회 2006 Biomedical Science Letters Vol.12 No.2

In relation to the tissue engineering, the cellular responses to the morphology of the scaffold surface are interesting topics. Human ligament fibroblasts (HLFs) were cultured on the micrpatterned silicone substrates subjected to cyclic stretch to simulate ligament motion. Groove and ridge width of silicone substrates was 10/50, 20/50, 20/10, and 20/20 μm (groove/ridge μm) with a depth of 3 μm. Strain was applied over two days for 4 hours per day with a frequency of 0.5 Hz with the magnitudes of 4 or 8%. The purpose of this study was to evaluate ligament fibroblast alignment and cellular responses in relation to the pattern of microgrooved surface and stretching magnitude. Ligament fibroblasts in the microgrooved surface were elongated and aligned parallel to the microgrooves under no stretch. Uniaxial cyclic stretch induced cellular activities and their orientation rise in cellular response and the cells showed alignment and elongation perpendicular to the direction of the stretch. Biochemical analyses showed that the best cellular response was found on the 20/50 μm under 8% stretch. The surface morphology and mechanical stretching were found to contribute to increase of proliferation, collagen production.