흡연에 의한 레진의 색상변화에 관한 실험적 연구

이용근,장광수,변호영 원광대학교 생체재료·매식연구소 1995 원광생체재료·매식 Vol.4 No.2

Extrinsic dental stain may cause considerable cosmetic problems. Cigarette smoking can stain intraoral restorations, and the extent of stain accumulation will very depending. on the chemical properties of materials, surface roughness and surface treatment. This laboratory investigation was designed to simulate clinical stain accumulation from smoking using a smoking chamber. The purpose of this study was to determine and compare the extent of stain on some dental resins caused by cigarette smoking using a color difference meter(CIELAB color scale). Four kinds of light cured composite resins. (ALF, EST, TPH, Z10), three kinds of acrylic denture base resins(VRS, VSC, PS2), enamel, and dentin were investigated. Resin specimens of 3 mm thickness were made according to the manufacturer's instructions and were finally polished with Microcloth(Buehler). Half of the specimens were thermocycled between 5-55 ℃ for 1,000 cycles. Enamel and dentin specimens were made by ground and polished until flat and polished. L, a and b value of specimens were measured using a Colorimeter (Model TC-6FX, Tokyo Denshoku Co.) All the specimens were initially exposed to the smoking chamber for 4 hours and then exposed an additional 4 hours. Conditions in the smoking chamber were 37℃ and 100% relative humidity. It was filled with cigarette smoke. After removal from the smoking chamber, the surface of each specimen was wiped with tissue paper and then L, a and b value of specimens were measured. After 4 hours of exposure, the discoloration of dentin and enamel was most prominent(p<0.05), and the color change of heat cured acrylic resin was the least followed by light cured composite resin. Thermocycling did not affect the amount of discoloration. The discoloration after 8 hours of exposure was significantly(p<0.05) greater than that after 4 hours, and the amount of discoloration was more than five times greater. In conclusion, 8 hours storage in a smoking chamber caused significant color change(ΔΕ). The stains were smallest on heat cured acrylic resin and light cured composite resin.

용접공들의 면역능에 관한 연구

이수일,조봉수,김영욱,고광욱,조원근,김영실,강수용,황인경,조병만,김돈균 大韓産業醫學會 1997 대한직업환경의학회지 Vol.9 No.1

The authors examined human immunity indicators such as CD4, CD8, Natural Killer(NK) cell, IgG, IgA, and IgM, and heavy metals such as Pb, Cr, Cd to evaluate the health hazard of welders. We selected total 126 male subjects, 60 welders who had more than 5 year working history as an exposure group, and 66 office workers and medical college students as a control group. This immunity evaluation approach is the first newly designed study that has never been tried in past studies on welder's heath evaluation. And the results were as follows. 1. Total lymphocyte count of peripheral blood was significantly higher in welder group, 2,615±650 ea/㎕ compared with 2,368±681 ea/㎕ in control group(p>0.05). 2. The proportion of CD4, CD8, NK cell in welder group was 37.5±9.4%, 24.0±8.8%, and 21.0±9.5%, respectively, and 35.5±6.5%, 25.0±6.9%, and 19.6±8.8% in control group. CD4 and NK cell were slightly higher, and CD8 was slightly lower in welder group. but there was no statistical significance between two groups(p≥0.05). 3. IgG, IgA, and IgM in welder group were 15.9㎎/㎗, 2.7㎎/㎗ and 1.5㎎/㎗, respectively, and 15.6㎎/㎗, 2.9㎎/㎗ and 1.7㎎/㎗ in control group. There was no statistical significance between two groups(p≥0.05). 4. Blood lead, cadmium and chromium concentrations were 4.2±1.8㎍/㎗, 0.4±0.38㎍/㎗, 1.2±0.6㎍/㎗ in welder group and 3.2±1.7㎍/㎗, 0.44±0.29㎍/㎗, 1.1±0.6㎍/㎗ in control group, respectively, and these value were within normal ranges.

폴리머 슬러리실 혼합물의 내구성 평가

이석근,이광호 경희대학교 산학협력기술연구원 1997 산학협력기술연구논문집 Vol.3 No.-

This study was conducted to evaluate the physical properties of polymer slurry seal mixtures for maintaining a uniform, smooth riding surface with minimal maintenance. The laboratory and the field test were performed to investigate the physical properties and the feasibility. The laboratory tests include Wet. Track Abration Test, Loaded Wheel Test, Cohesion Test, Hubbard Field Test, and Wheel Tracking Test. The results of this evaluation indicate that the polymer slurry seal mixtures perform better than the normal slurry seal without polymer modifier in terms of improvement of cohesion, toughness and breaking times. The result of the field test also shows that polymer slurry seal is superior to any other surface treatment materials which were construructed in the field to compre with polymer slurry seal.

이종 장기 이식을 위한 다단계 거부 반응의 조절

이광수,김영관,박희진,이재오,명평근 忠南大學校 生命科學硏究院 醫藥品開發硏究所 2006 藥學論文集 Vol.21 No.-

The transplantation of organ, tissues or cells between individuals of different species has been of increasing interest in recent years because the use of animals as organ and tissue donors as a source of transplants would overcome the severe and worsening shortage of human organs available for transplantation. However, There are some major hurdles to the clinical application of xenotransplantation; the immunologic response of the recipient against donor, the physiology of the graft, and the possibility that a xenotransplant might transmit an infection from the source to the recipient. This review describes the unique aspects of the immunological barrier to transplanting organs from non-primates such as pigs into humans, focusing especially on the mechanisms which contribute to immunorecognition, physiology of the rejection and infectious hurdles to xenotransplantation. This communication might be applied to overcoming these hurdles and the possibility that genetic strategies might be used to expand the potential applications of xenotransplantation for the treatment of human disease.

생활체육교실 참가 만족도 및 운영방안

이일재,이광근 한국스포츠리서치 2003 한국 스포츠 리서치 Vol.14 No.6

The purpose of this study is to search for participation satisfaction and management plan for the activation of Sport for All class. The population of this study are the participants of Sport for All class held in Jeonju city in 2003. The valid samples are 346 persons at last among 400 persons except the 54 persons whose validity are determined low. To process the statistics Frequency Analysis, Chi-square Test, t-test, one-way ANOVA at .05 significant level using SPSS 10.0. Following conclusions were gained through these research process. To activate Sport for All class, marketing concept which satisfy Participants demands is demanded. It requires establishment of specific and practical management plan such as, 1) having program diversifying for continuous participants 2) having 4 times per year 3) continuous efforts of line and bulletin board advertisement on TV 4) establishment of fund of Sport for All 5) continuous efforts of solving traffic inconvenience, improper distinction and insufficient instructor 6) having weekend class.

原子力 發電所 使用後 核燃料 貯藏 方案의 比較 分析

李源根,金洸杓 慶熙大學校 1994 論文集 Vol.23 No.-

At present all the discharged spent nuclear fuells are stored in at-reator (AR) pools of each nuclear power plant in Korea, but most of the exciting AR pools will lose their full core reserve capacities in the late of 1990s Untill the long-term spent nuclear fuel management policy will be established, this cummulative spent nuclear fuels should be safely stored in an applicable storage facility. By this study results, the alternatives to solve this storage problem of the cummulative spent nuclear fuels are recommended as the followings : If the policy making would be done in the near future, the storage capacities of the existing pools would be expanded by the replacement of the old racks into or the installation of high density racks, and, if it could not be, a centralized wet or dry storage management of the spent nuclear fuels should be more reasonable.

화상을 입은 백서에서 식이의 성분이 세균전위에 미친 영향

이광만,이경근,조지현 圓光大學校 醫科學硏究所 1997 圓光醫科學 Vol.13 No.1-2

Bacterial translocation means the passage of viable bacteria from the gastrointestinal tract to normally sterile tissues such as the mesenteric lymph nodes and other internal organs. It is now clear that translocation is increased in bums and in injury including hemorrhagic shock. Total parenteral nutrition and elemental enteral diets are thought to be associated with atrophy of the intestinal mucosa and increased translocation. The purpose of this study was to determine whether or not the composition of nutrients effects on bacterial translocation in normal and burned rats. 54 male Sprague-Dawley rats were randomized to 3 groups of 18 animals each. Group Ⅰ was non-burned control rats, and group Ⅱ and Ⅲ were burned rats. Rats in group Ⅱ and Ⅲ were subjected to contact dermal bum of 10% and 20% each of their body surface area. All 3 groups were re-randomized to 3 subgroups of 6 animals each; subgroup 1 fed rat chow, subgroup 2 fed elemental diet(Energen®) and subgroup 3 fed oral TPN solution. Animals were fed respective diets ad libitum for 2 weeks, and then mesenteric lymph nodes, portal vein blood, and cecal content were aseptically obtained for culture. Bacterial count in mesenteric lymph nodes(MLN) of burned rats was significantly increased than that of non-burned rats(p=0.033). In burned rats, MLN bacterial count was the highest in the rats fed oral TPN (566.1±870.5/g vs. 270.1±382.4/g in the rats fed elemental diet and 164.9±184.7/g in the rats fed chow). Cecal culture in burned rats revealed a statistically significant increase in the cecal anaerobic count in the rats fed oral TPN when compared to the rats fed chow or elemental diet(p=0.003). There was close correlation between MLN bacterial count and cecal aerobes count(r=0.843, p=0.001). In conclusion, the type of nutrients had influence on bacterial translocation in burned animals partly by increasing the cecal bacterial population.

γ선에 의한 말단팬텀에서의 선량분포 연구

이원근,김광표 경희대학교 산학협력기술연구원 1995 산학협력기술연구논문집 Vol.1 No.-

In 1995, The American National Standard Institute(ANSI) is planning to release a standard for the performance testing of personnel extremity dosimeters as ANSI N13.32 standard. The standard is applicable to a personnel extremity dosimeter process used for determing the dose equivalent to the extremities at the reference depth of 7㎎/㎠, as recommended by the International Commission for Radiation Units and Measurements Reports 39. In this study, theoretical calculations of dose equivalent were performed by using a Monte Carlo N-particle transport code for the two types of extremity phantom: one to represent a lower arm or leg composed of tissue and bone to test wrist or ankle dosimeters, and the other to represent a finger to test ring of hand dosimeters. The dose equivalent of the two extremity phantoms by taking consideration of the distribution of absorbed dose due to the interaction of homogeneous parallel broad beam of monoenergetic primary photons in the range between 15 keV and 1.5 MeV result from the kerma approximation with the Monte Carlo method.

중국의 '서부대개발'과 자동차 산업 : 한국에의 시사

이승훈,김광억,이근,은종학 서울대학교 사회과학연구원 2001 한국사회과학 Vol.23 No.2

본고는 중국의 서부대개발 정책의 내용과 향후 전망 및 이 정책이 가지는 중국 자동차 산업에의 시사를 찾고자 하였다. 중국 서부지역의 주민들의 의식이나 인프라 등은 동부 대도시의 80년대 말 상황과 비슷할 정도로 뒤떨어져 있다. 서부대개발이 중국정부의 장기적인 프로젝트인 만큼, 우리도 중국 서부를 장기적으로 인식해 적절한 전략적 접근이 필요하다. 한국의 자동차 산업과 기업이 얻을 수 있는 시사점은, 장기적 비전과 전략적 접근의 필요성 외에 다음과 같은 것들이 있다. 첫째, 같은 서부지역이라도 소득수준과 교통 인프라 차원에서 우수한 몇몇 省·市(중경, 사천, 섬서 등)가 서부지역의 발전을 주도할 것이기 때문에 이들 지역을 통한 단계적 진입 전략이 필요하다. 둘째, 서부대개발에 따른 자동차 수요증가는 차종에 따라 달리 나타날 것이므로 이에 대한 고려가 필요하다. 즉, 화물차에 대한 수요증가는 직접적으로 나타날 것이나, 일반승용차에 대한 수요증가는 간접적이고 또한 그 정도도 제한적일 것이다. 셋째, 중국의 자동차 시장은 지역분할 구도의 약화, 시장경쟁의 격화, 유통구조의 개편, 개인구매의 증가 등의 변화를 겪고 있어, 이 같은 자동차 시장 자체의 역동성에 적절히 대응해야 한다 This paper first discusses the main contents and prospect of the Great West Development project of China and then tries to find implications of this project for automobile makers. First we note that this project spans a very long time horizon and thus the firms should approach this with a long term oriented view, rather than expecting any short term benefits. Also, because the projects, especially during the early stage, will be led by selective fore-running regions, like Chungqing, Sichuan and Shaanxi, the firms should take a differentiated and gradual approach. Expansion of demand for automobiles will be different depending upon the kinds of cars. Initial expansion will be more for trucks whereas demand for passenger cars will be indirect or limited. At the moment, the automobile industry in China is undergoing radical changes in terms of regional distribution of market power among the major makers, ever-increasing market competition, changes in the marketing networks, and increasing participation of individual customers. This kind of industrial dynamism should be fully considered in designing corporate strategy or public policy.

인간 재조합 인터루긴-32 면역조절작용에 대한 유세포 분석

이광수,김영관,채정일,심정현,김은미,강형식,김수현,윤도영,명평근 충남대학교 생물공학연구소 2006 생물공학연구지 Vol.12 No.-

Xenotransplantation of porcine organs has the potential to overcome the severe shortage of human tissues and organ available for human transplantation. however, it remains various hurdles for clinical xenotransplantation. In pig and mouse xenotransplantation, porcine xenograft evoke a strong cellular rejection response in immunocompetent host and grafts are destroyed within a week. This cellular immune response could involved both T cells and NK cells. A number of groups have shown that human NK cells can recognize and damage porcine endothelial cells. In addition, human T cells can respond to porcine endothelial cells through both direct and indirect mechanisms. Cellular rejection of porcine tissues requires T cells, particularly CD4^(+) cells. A new cytokine recombinant human interleukin-32α,β(IL-32α,β) has a role innate and acquired immune system. In order to investigate the role of recombinant mouse IL-18 and recombinant human IL-32α,β in xenograft rejection, we transplanted the PK(15) cells to C57BL/6 mice with or without intraperitoneal injection of recombinant mouse IL-18 or recombinant human IL-32 α,β. It was analyzed the population of NK cell, T cell and B cell in the C57BL/6 mice transplanted with PK(15) cells and recombinant mouse IL-18 or recombinant human IL-32α,β by flow cytometry analysis. As a result, lymph node and thymus of PK15/IL18, PK15/IL32α and PK15/IL32β injected group were increased to T cell activation population than normal injected groups. CD8^(+) T cells were decreased in lymph node of PK15/IL18, PK15/IL32α and PK15/IL32β injected groups. CD4^(+) T cells were increased in lymph node cell of PK15/IL32α and PK15/IL32β injected group and also, B cell population were increased in lymph node cell and spleen of PK15/IL18, PK15/IL32α and PK15/IL32β injected group. Therefore, we suggest that recombinant mouse IL-18 and recombinant human IL-32α,β suppress xenograft rejection in cellular xenotransplantation.