PEG 분해균주의 분리와 PEG film의 상용성에 관한 연구

이제혁,정성제,이준열,전억한 경희대학교 부설 식량자원개발연구소 1993 硏究論文集 Vol.14 No.-

PEG를 sole carbon과 energy source로서 이용하는 미생물을 자연계에서 분리하였고, PEG의 분자량이 높아질수록 그 분해 미생물의 수가 감소하는 것을 확인하였다. 또한, liquid culture로서 PEG농도를 감소시키는 미생물을 선별하였고, 분해율은 PEG 8000이 약 18.8%였으며 PEG 10000은 약 25.4%인 것으로 조사되었다. PEG film의 제조를 위해 EMAA 및 EAA와의 상용성을 적외선 분광(IR) 스펙트럼을 사용하여 조사한 결과, EMAA와 EAA의 카르보닐기와 PEG의 에테르기와의 강한 수소결합이 형성으로 blend film제조시 상용성이 있는 것으로 확인되었다. Several strains capable of degrading PEGs(Polyethylene Glycols)were isolated and investigated for their biodgradation ability of PEGs. Microorganisms screened for the biodegradation studies were those grown on the PEG used as a sole carbon and energy source. It was known that the number of microorganisms decreased when grown on the high molecular weight of PEG(e.g. 20,000). A liquid culture was carried out with such microorgaisms and resulted in the decrease in PEG concentration meaning that PEG was degraded in the reactor. The biodegradability was found to be about 18.8% for PEG-8000 and 25.4% for PEG-10000, respectively. For the manufacture of biodegradable PEG film, EMAA/PEG and EAA/PEG blending ability was investigated with IR spectrum and showed that it was possible to produce blending film.

영아의 혀에 발생한 유아조직 1례

이희정,윤은실,최준혁,최광해 영남대학교 의과대학 2005 Yeungnam University Journal of Medicine Vol.22 No.2

Tongue tumors of pediatric patients are the most common soft tissue tumor of pediatric oral and maxillofacial tumors. There are many kind of pediatric tongue lesions such as hemangioma, lymphangioma, papilloma, and cyst. Most of these lesions are benign, but malignant tumors of tongue may be occurred. Therefore, malignancy should be ruled out Sometimes, tongue lesions are present with dyspnea, dysphagia, dyarthria, bleeding, or cosmetic problem. We experienced a case of chronic inflammatory mass on posterior 1/3 of symptom occurred because of tongue mass effect. The tongue mass was confirmed as granulation tissue by microscopic examination After excision of tongue mass, she had no problem with swallowing and breathing.

광조형 시스템의 정밀조형을 위한 지지대 자동 생성 시스템 개발

강혁준,이형국,김효찬 동의공업대학 2000 論文集 Vol.26 No.1

Support structures are used to support a component during building process and must be removed once the building is complete. For precise building this paper specified types of support structures by means of geometry characteristics. They are point, line and area. And found a new algorithm for detecting geometries which need support structures. For easy of removing support structure teeth profile generation and interferences avoidance algorithm was studied.

배양골세포 이식이 치조골재생에 미치는 영향

정순준,허익,박준봉,이만섭,권영혁 慶熙大學校 齒科大學 1995 慶熙齒大論文集 Vol.17 No.2

This study was performed to estimate the effects of cultured bone cell inoculated on porous type hydroxyaptite for the regeneration of the artificial alveolar bone defect. In this experiment 3 beagle dogs were used, and each of them were divided into right and left mandible. Every surgical intervention were performed under the general anesthesia by using with intravenous injection of Pentobarbital sodium (30mg/Kg). To reduce the gingival bleeding during surgery, operative site was injected with Lidocaine hydrochloride (1:80,000 Epinephrine) as local anesthesia. After surgery experimental animal were feeded with soft diet(Mighty dog, Frisies Co., U.S.A.) for 1 weeks to avoid irritaion to soft tissue by food. 2 months before surgery both side of mandibular 1st premolar were extracted and bone chips from mandibular body were obtained from all animals. Bone cells were cultured from bone chips obtained from mandible with Dulbecco's Modified Essential Medium contained with 10% Fetal Bovine Serum under the conventional conditions. Porous type hydroxyapatite were immerse into the high concentrated cell suspension solution, and put 4 hours for attachment the cells on the surface of hydroxyapatite. Graft material were inserted on the artificial bone defect after 3 days of culture. Before insertion of cell-inoculated graft material, scanning electronic microscopic observation were performed to confirm the attachment and spreading of cell on the hydroxyapatite surface. 3 artificial bone defects were made with bone trephine drill on Abe both side of mandible of the experimental animal. First defect was designed without insertion of graft material as negative control, second was filled with porous replaniineform hydroxyapatite inoculated with cultured bone marrow cells as expermiental site, and third was filled with graft materials only as positive control. The size of every artificial bone defect was 3 mm in diameter and 3 mm in depth. After the every surgical intervention of animals, oral hygiene program were performed with 0.1% chlorhexidine digluconate. All of the animals were sacrificed at 2, 4, 6 weeks after surgery. For obtaining histological section, tissus were fixed in 2.5% Glutaldehyde and decalcified with Planko-Rycho Solution for 72 hr. Tissue embeding was performed in paraffin and cut parallel to the surface of mandibular body. Section in Bum thickness of tissue was done and stained with Hematoxylin-Eosin. All the specimens were observed under the light microscopy. The following results were obtained. 1. In the case of control site which has no graft material, less inflammatory cell infiltration and rapid new bone forming tendency were revealed compared with experimental groups. But bone surface were observed depression pattern on defect area because of soft tissue invasion into the artificial bone defect during the experimental period. 2. In the porous hydroxyapatite only group, inflammatory cell infiltration was prominet and dense connective tissue were encapsulated around grafted materials. osteoblastic activity in the early stage after surgery was low to compared with grafted with bone cells. 3. In the case of porous hydroxyapatite inoculated with bone cell, less inflammatory cell infiltration and rapid new bone formation activity was revealed than hydroxyapatite only group. Active new bone formation were observed in the early stage of control group. 4. The origin of new bone forming was revealed not from the center of, defected area but from the surface of preexisting bony wall on every specimen. 5. In this experiment, osteoclastic cell was not found around grafted materials, and fibrovascular invasion into regions with no noticeable foreign body reaction. Conclusively, the cultured bone cell inoculated onto the porous hydroxyapatite may have an important role of regeneration of artificial bone defects of alveolar bone.

자율 이동 로봇의 장애물 회피 기술 동향

이 재 성,유 준 혁 대구대학교 정보통신연구소 2014 情報通信硏究 Vol.10 No.1

본 논문은 자율 이동 로봇의 장애물 회피와 관련된 기술동향을 분석하였다. 산업현장, 공공 및 개인 서비스 분야에서 다양하게 사용 중인 이동 로봇에서 안전과 가장 밀접된 장애물 충돌 회피를 위해 사용하는 다양한 기법들을 소개하고, 특히 인공전위계 알고리즘(Artificial Potential Field), 가상역장(Virtual Force Field) 알고리즘, 탄성력(Elastic Force) 알고리즘 등을 분석하고 각각의 장·단점을 도출하였다. This paper presents, the trend of technology regarding obstacle avoidance for autonomous mobile robots. The mobile robots are widely used in various fields such as industry and public personal service area. This paper introduces several techniques of the collision avoidance sith obstacles, which is closely related to the safety, especially three algorithms of artificial potential filed, virtual force field and elastic force are analyzed by figuring out pros and cons of each one.

Flowable Composite Resin의 미세변연누출 및 전단결합강도

박성준,오명환,김오영,이광원,엄정문,권혁춘,손호현 대한치과보존학회 2001 Restorative Dentistry & Endodontics Vol.26 No.4

상악 유전치의 치근단 병소로 인한 만곡 영구전치

지혁준,최병재,이제호 대한소아치과학회 2001 大韓小兒齒科學會誌 Vol.28 No.1

치아만곡은 조직-형태분화기에 나타나는 치아형태의 이상으로 석회화된 부위와 미석회화된 부위간의 장애로 인해서 치관 및 치근 모두에서 발생하는 기형이며, 상악 절치에서 호발하며 매복 가능성이 높다고 보고되었다. 만곡의 원인으로는 유치의 외상, 치배의 이소성 발육, 낭종이 있으며 그외에 otodental syndrome, 쇄골두개이골증에서 보고되었다. 본 증례는 치아우식증으로 인해서 발생된 치근단병소가 치아만곡을 유발할 수 있는 원인이 될 수 있다고 생각하였기에 이에 보고하는 바이다. Dilaceration is a tooth abnormaly occuring in the histo-morphodifferention stage resulting from disturbance between the uncalcified and already calcified portion that affects both the crown and root. The involved tooth is usually the maxillary central incisor and it also shows high prevalence of impaction. The cause of dilaceration can be either from the trauma of the primary tooth, ectopic development of the tooth germ or from cysts. And it is also found in some cases of Otodental syndrome, Hurler syndrome, Cleidocranial dysostosis. The purpose of this study is to show that periapical lesions caused by dental caries can be another factor in causing dilacerations.

Diethyl 1-chloro-2-phenyl-2-(tosyl) aminoethylphosphonate 의 결정 및 분자구조

김대영,이재혁,신준철,김문집 순천향대학교 기초과학연구소 1997 순천향자연과학연구 논문집 Vol.3 No.1

The crystal and molecular structure of diethyl 1-chloro-2-phenyl-2-(tosyl)aminoethyl phosphonate has been determined from single crystal X-ray diffraction study ; C19H25NO5PCIS, Monoclinic, P2₁/a, a=10.8507(11)Å, b=16.1201(12)Å, c=12.7354(12)Å, β=90.192(7)°, V=2227.6(3)ų, T=293(2)K, Z=4, Cuk α(λ=1.54178Å). The structure was solved by direct method and refined by full-matrix least squares to a final R=5.17% for 2444 unique observed F0> 4σ(F0) reflections and 254 parameters.

치주인대세포와 치은 섬유아세포의 혼합배양이 석회화 결절형성에 미치는 영향

인영미,박준봉,권영혁,이만섭 慶熙大學校 齒科大學 1995 慶熙齒大論文集 Vol.17 No.2

The goal of periodontal therapy is to regenerate the loss of periodontal attachment appratus. Current theories suggest the cells of the periodontium have the capacity, when appropriately triggered, to actively participate in restoring connective tissues, including mineralized tissues. This study was performed to define the hard tissue regeneration effect of periodontal ligament (PDL) cells in nitro and the effect of rate of the composition in gingival fibroblasts (GF) on the hard tissue regeneration capacity of PDI_ cells. For this study, Cell growth rate, alkaline phosphatase(ALPase) levels and the ability to produce mineralized nodules in co-culture of PDL cells and GF were examined. The results were as follows ; 1. At 7 and 15 days, cell growth of co-culture of PDL and GF (50 : 50) was greater than that of PDL cells or GF alone(P<0.05). 2. Measurements of ALPase levels indicated that PDL cells had significantly higher activity when compared with that of co-culture groups and GF only(P<0.05). And, ALPase activity in 10 days was higher than that of 7 days(P<0.05). 3. The tendency of formation of the mineralized nodule were observed dose-depend pattern of PDL cells. There was statistically significant difference among group 1(PDL 100%), 2(PDL 70% GF 30%), and 3(PDL 50% = GF 50%)(P<0.01). But, there was no difference among group 3, 4(PDL 30% : GF 70%), and 5(GF 100%). 4. Also, the number of nodule was greater in co-culture of PDL 70% and GF 30% than in culture of PDL 70%(P<0.05). From the above results, it is assumed that the co-culture of PDL cells and GF stimulates the cell growth, which is not that of PDL cells but GF. And, the activity of ALPase depends on the ratio of PDL cells, and ALPase may relate to the initial phase of nodule formation. Also, it is thought that the calcified nodule formation principally depends on PDL cells, is inhibited by GF, and affected by cell density.

티타늄 표면에 대한 배양 골수세포와 치은 섬유아세포의 생체적합성

오충영,박준봉,권영혁,이만섭 慶熙大學校 齒科大學 1995 慶熙齒大論文集 Vol.17 No.2

The purpose of this study was to evaluate the response in aspect of attachment and growth rate of osteablasts and human gingival fibroblasts to the commercially pure titanium(CP titanium) and titanium alloy(Ti-6A1-4V) that are used widely as implant materials, and to obtain the basic information to ideal implant materials. In this study, commercially pure titanium in first test group, titanium alloy(Ti-6A1-4V) in second test group, cobalt-chromemolybdenum alloy(Co-Cr-Mo alloy) in positive control group, and tissue culture polystyrene plate in negative control group were used. The results of this study were as follows. 1. Bone marrow cells cultured on CP titanium and Ti-6A1-4V showed significantly greater attachment and growth rate(p<0.05) compared to Co-Cr-Mo alloy in each time. 2. There were no significant differences(p>0.05) in attachment and growth rate of bone marrow cells cultured on GP titanium and Ti-6A1-4V or tissue culture plate. 3."Most bone marrow cells cultured on CP titanium, Ti-6A1-4V and tissue culture plate were attached well to each substratum in first 2days, and then, grew at higher growth rate. On the other hand, some cells cultured on Co-Cr-Mo alloy failed to attach in first 2 days, and then, attached cells grew at lower growth rate than other groups. 4. Attachment and growth rates of gingival fibroblasts cultured on CP titanium and Ti-6A1-4V showed no significant differences(p>0.05) compared to Co-Cr-Mo alloy in 2 days, but significantly greater increase(p<0.05) in 5 and 9 days. 5. There were no significantly differences(p>0.05) between growth rates on gingival fibroblasts cultured on CP titanium, Ti-6A1-4V and tissue culture plate in 2 and 5 days, but a significant lower growth rate(p<0.05) on CP titanium and Ti-6A.1-4V versus tissue culture plate. 6. Some gingival fibroblasts cultured on all specimen groups failed to attach, but attached cells grew well especially on CP titanium, Ti-6A1-4V and tissue culture plate. 7. There were no significant differences(p>0.05) between growth rates of both bone marrow cells and gingival fibroblasts cultured on CP titanium and Ti-6A1-4V. As a result of this study, both commercially pure titanium and Ti-6AI-4V showed excellent biocompatibility and there was no significant difference in the cellular response to the both metals. Bone marrow cells cultured on each substratum showed significantly greater growth rate and responded sensitively to cytotoxic effects of metal surfaces compared to gingival fibroblasts. Considering cell response to the substrate, it was likely that the composition itself of titanium metals have no significant effects on the biocompatibility. Further study need to be done to evaluate the influence of surface characteristics on cellular responses.