방사선조사가 Porphyromonas gingivalis에 미치는 영향

이창환,김규태,최용석,황의환 대한구강악안면방사선학회 2008 Imaging Science in Dentistry Vol.38 No.1

Purpose : The aim of this study was to observe a direct effect of irradiation on the periodontopathic Porphyromonas gingivalis (P. gingivalis). Materials and Methods : P. gingivalis 2561 was exposed to irradiation with a single absorbed dose of 10, 20, 30, and 40 Gy. Changes in viability and antibiotic sensitivity, morphology, transcription, and protein profile of the bacterium after irradiation were examined by pour plating method, disc diffusion method, transmission electron microscopy, RT-PCR, and immunoblot, respectively. Results : Viability of irradiated P. gingivalis drastically reduced as irradiation dose was increased. Irradiated P. gingivalis was found to have become more sensitive to antibiotics as radiation dose was increased. With observation under the transmission electron microscope, the number of morphologically abnormal cells was increased with increasing of irradiation dose. In RT-PCR, decrease in the expression of fimA and sod was observed in irradiated P. gingivalis. In immunoblot, change of profile in irradiated P. gingivalis was found in a number of proteins including 43-kDa fimbrillin. Conclusion : These results suggest that irradiation may affect the cell integrity of P. gingivalis, which is manifested by the change in cell morphology and antibiotic sensitivity, affecting viability of the bacterium.

만성 췌장염에 의한 십이지장 협착 1예

서백종,장기육,박용근,채현석,한석원,이창돈,정인식,차상복,박두호 대한내과학회 1997 대한내과학회지 Vol.53 No.3S

저자들은 만성췌장염환자에서 지속적인 오심과 구토를 주소로 내원하여 십이지장협착으로 진단된 1예를 경험하였기에 보고하는 바이다. Duodenal stenosis resulting from fibroinflammatory process is a rare complication of chronic pancreatitis. The mechanism of duodenal stenosis seems to be related to ischemia and edema caused by persistent inflammation, which results in irreversible change of duodenal wall structure. We experienced a chronic alcoholic male patient with duodenal stenosis who had a history of choledochojejunostomy to relieve distal bile duct stenosis several years ago. He had suffered persistent postprandial nausea and vomiting for several months. Barium study of upper gastrointestinal tract and repeated endoscopy show narrowing lumen of duodenum with coarse nodular surface due to reactive inflammatory change.

Cone beam형 전산화단층촬영장치를 이용한 하악 제1대구치 근심 치근의 danger zone에 관한 연구

장유리,최용석,최기운,박상혁 대한구강악안면방사선학회 2007 Imaging Science in Dentistry Vol.37 No.2

Purpose : To examine the danger zone of mesial root of mandibular first molar of patient without extraction using CBCT(cone -beam computed tomography) to avoid the risk of root perforation. Materials and Methods : 20 mandibular first molars without caries and restorations were collected. CT images were obtained by CBCT(PSR9000N TM, Asahi Roentgen Co., Japan), reformed and analyzed by V-work 5.0 (CyberMed Inc., Korea). Distance between canal orifice and furcation was measured. In cross sectional images at 3, 4 and 5 mm below the canal orifice, distal wall thickness of mesiobuccal canal (MB-D), distal wall thickness of mesiolingual canal (ML-D), distal wall thickness of central part (C-D), mesial wall thickness of mesiobuccal canal (MB-M) and mesial wall thickness of mesiolingual canal (ML-M) were measured. Results : The mean distance between the canal orifice and the furcation of the roots is 2.40 mm. Distal wall is found to be thinner than mesial wall. Mean dentinal wall thickness of distal wall is about 1 mm. The wall thickness is thinner as the distance from the canal orifice is farther. But significant differences are not noted between 4 mm and 5 mm in MB-D and C-D. MB-D is thinner than ML-D although the differences is not significant. Conclusion : The present study confirmed the anatomical weakness of distal surface of the coronal part of the mesial roots of mandibular first molar by CBCT and provided an anatomical guide line of wall thickness during endodontic treatment.

40ㆍ50대 일부 남성근로자의 골감소증 및 골다공증 유병실태와 위험요인

장윤균,서현주,진영우,정미선,성숙희,박두용,김종순,김수근 大韓産業醫學會 2006 대한직업환경의학회지 Vol.18 No.2

목적: 최근 국내에서도 골다공증과 관련된 생활양식의 규명에 관한 연구가 이루어지고 있으나, 아직까지 남성 골다공증에 대한 연구가 활발하게 이루어지지 않아 40, 50대 남성근로자를 대상으로 유병률을 파악하고, 골감소증 및 골다공증 관련 위험요인을 확인하고자 하였다. 방법: 원자력발전소에 근무하는 40, 50대 남성 근로자 2,073명을 대상으로 2004년 3월~7월 기간동안 생활습관을 파악하기 위하여 자기기입식 전산입력 방식으로 최종학력, 흡연여부, 음주여부, 신체활동 횟수를 조사하였고, 골밀도검사, 체성분검사(체지방률, 허리-엉덩이둘레비), 신체계측(신장, 체중)을 시행하였고, 골밀도 검사는 Osteosys사의 EXE-3000을 이용하여 종골부위를 측정하였고, 체지방률, 허리-엉덩이 둘레비는 Biospace사의 Inbody 3.0을 이용하여 측정하였다. 통계분석은 골감소증 및 골다공증의 관련요인을 분석하기 위해 다중로지스틱회귀분석을 시행하였다. 결과: 연구대상자의 골감소증 및 골다공증 유병률은 22.8%와 3.0%이었으며, 골감소증 및 골다공증의 관련요인으로는 연령이 증가할수록, 흡연자이거나 과거흡연자일 경우, 체질량지수가 25 kg/m^(2) 미만일 경우, 30분 이상 신체활동 횟수가 주 3회 미만일 경우가 유의한 연관성이 있었다. 결론: 성인 남성 40, 50대의 골감소증 및 골다공증의 유병률이 높은 편이었으며, 골감소증 및 골다공증으로 이환을 예방하기 위하여 금연, 활발한 신체활동을 촉진하여 골밀도를 개선시키는 생활습관으로의 변화를 권고해야 할 것이다. Objective: This study was conducted to investigate the prevalence and risk factors of osteopenia and osteoporosis in 40-59 year-old male workers working at nuclear power plants. Methods: Bone density, body composition, and anthropometry data were analyzed for 2,073 subjects were carried out from March 2004 to July, 2004. Educational level, smoking status, drinking status and frequency of physical activity were investigated by self-reported questionnaires through internet to identify lifestyles related to bone mass density. Bone mass density was measured by EXE-3000 of Osteosys Co. And body fat percentage, and waist-to-hip ratio by inbody 3.0 of Biospace Co. Results: The prevalence of ostepeniaosteopenia and osteoporosis was 22.8% and 3.0%, respectively. According to multinominal multinomial logistic regression analysis, age, smoking status (current smoker and former smoker), low body mass index (< 25kg/m^(2)), and frequency of physical activity were significantly associated with osteopenia and osteoporosis. Conclusions: The prevalence of ostcopenia and osteoporosis wasseemed high for the, when it was inferred from subjects' age compared to the results of previous studies. The This study results suggeststhat it is necessary for 40-59 year-old male workers to stop smoking, and exercise regularly in order to prevent osteopenia and osteoporosis.

폐탄광 배수에 의한 주변 화천 오염 실태 조사

조경숙,장용근,류희욱 崇實大學校 生産技術硏究所 1996 論文集 Vol.26 No.1

The survey was carried out to investigated the contamination of streams by the acid mine drainage originates from abandoned coal mines and coal refuse piles. The physico-chemical characteristics such as pH, sulfate and elements concentrations of waters and sediments in streams were analyzed, and the microbial activities in the sediments were evaluated by measuring dehydrogenase activities. In sites contaminated by the acid mine dranage, the pH of waters adn sediments declined to acid from neutral due to the accumulation of sulfate. Dehyfrogenase activities ranged from 12 to 170 ㎍-TPF·g-dry soil-¹·24h-¹in the contaminated sites, whereas teh uncontaminated sites had activities of 1,176-4,259 ㎍-TPF·g-dry soil-¹·24h-¹. Dehydrogenase activities were significantly affected by low pH of sediments, indicating that high strength of sulfate inhibited microbial activities. The concentrations of heavy matals such as Pb and Fe in contaminated sediment (37-46 ppm Pb; 46,000 ppm Fe) were much higher than those in the uncontamnated sediments. concentration of Al in the contaminated water acidfied by the abandoned coal drainage was in range of 11 to 42 ppm. compared with those in the uncontaminated sediments, the concentrations of Mn, Mg and Ca in contaminated sediments were low because of the leaching of them from soil to water by acidfied stream water.

생체분해성 망막압정을 이용한 망막고정에 대한 실험적 연구

김용백,민병무,김창식,박근성,김승영,길숙종,조항진,이성복,노승무,송규상,강대영,조준식,양준묵,정경수,최선웅,이진호,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

Biodegradable retinal fixation devices obtain mechnical fixation of the retina with desirable chorioretinal scarring and with the potential for local, sustained release of antimetabolites and steroids to inhibit proliferative vitreoretinopathy. We manufactured a biodegradable retinal tack with barb that was designed in order to prevent intrusion from implantation of retinal tacks. This study was carried to evaluate the efficacy for retinal fixation and the capability for sustained release of drugs with a newly designed biodegradable retinal tack Biodegradable retinal tacks were made of polymers of glycolic acids and were designed with barbs in a shape to prevent the disinsertion. Biodegradale retinal tacks are divided into 3 parts, a conical portion that is inserted into the sclera, a cylinder portion that remains in the vitreous, and a neck portion between the pin and the cylinder. The tapered conical end was manufactured to allow easy insertion through the retina and choroid into the sclera. A cylinder portion was manufactured with a tapered angle that fixes firmly into the orifice of 19 gauge spinal needle. A neck portion, 0.4 mm in diameter, was designed to prevent disinsertion from following implantation of retinal tack. The applicator was a 19 gauge spinal needle and its orifice was prepared to 15°angle to accept the tapered cylinder portion of the retinal tack. The retinal tacks, secured in the needles, were passed through the formed vitreous and inserted into the retina, choroid, and sclera and were released by pushing the internal needle, usually within 2-3mm of the medullary ray of the posterior rabbit retina A retinal tack was placed in each of 8 pigmented rabbit eyes. Slit-lamp biomicroscopy, indirect ophthalmoscopy and fundus photography were performed periodically from 1 day to 8 weeks after surgery. Eight eyes were enucleated and studied by light microscopy at 8 weeks. Biomicroscopic evaluation of the animals revealed edemas adjacent to the retinal surfaces immediately after insertion of the biodegradable retinal tacks in all the animals. These edemas disappeared after 1 week. The first noticeable change in the size of retinal tacks was shown after 2weeks. The size of the retinal tacks gradually got smaller, decreasing to about one-half at 4 weeks and about one-third at 8 weeks. All retinal tacks remained in inserted places without any movement for an 8 week period. On light microscopy, epiretinal proliferations were seen to extend into the vitreous cavity. Cellular capsules that lined the inner aspect of the scleral defect caused by tack insertion were found. However the adjacent retina had a normal cytologic appearance and architecture in all specimens. We manufactured a biodegradable retinal tack that is designed to prevent intrusion from implantation of retinal tacks. All biodegradable retinal tacks reduce in size with time, but no retinal tacks extruded from the inserted place. The newly designed biodegradable retinal tack can be used for retinal fixation and may be used as a vehicle for the introduction of pharmacologic agents to prevent the cellular events that promote proliferative vitreoretinopathy.

댄스스포츠 참여가 청각장애인의 사회,정서 발달에 미치는 영향

이창규,현광석,조병준,김영표,김용진 한국특수체육학회 2002 한국특수체육학회지 Vol.10 No.2

The purpose of this study was to find out the effects of participation in dance sport programs on development of social-emotional behaviors of deaf students. The subjects were 20 deaf students of middle and high school for special education, and the subjects were randomly devided into participant group(n=10) and non-participants group(n=10). Meadow/Kendall social-emotional asessment inventory for the deaf students(1980) by Kim(1990) were administered by specialized teachers of the students. The statistical procedures used to analysed the hypotheses were ANCOVAs. The major findings of this study were that deaf students who regularly participated in dance sport activities had significantly higher level of the development of social adaptation, self-consciousness, and emotional adaptation rather than non-participants. It could be concluded in this study that sport activities had significant effects on the development of social-emotional behaviors of deaf students.

연령증가에 따른 혈압요소들의 좌심실비대 및 관동맥질환과의 관련성

박재석,박창규,박미영,박재형,김용현,나진오,신성희,서순용,홍순준,박성미,임홍의,김응주,서홍석,오동주,노영무 대한순환기학회 2004 Korean Circulation Journal Vol.34 No.2

발전기 안정화 운전을 위한 PSS 파라미터 선정

김창석,황석영,서진연,정삼용 조선대학교 동력자원연구소 1995 動力資源硏究所誌 Vol.17 No.1

This paper describes the proper selection method of the power system stabilizer(PSS) parameter for stabilizing operation of a synchronous machine which connected to infinite bus by using pole assignment method. The purpose of PSS is to enhance the damping capability at small frequency oscillation (0.5∼2㎐). It can be achieved by moving the real part of critical eigenvalue (pole) on left side of s-plane. The PSS parameter was selected by using the proposed method to match with a pre-assigned pole associated with poorly damped swing mode. This method has been studied to synthesize the PSS on Yong-Gwang N/P. And the simulation results show that the selected parameter by using proposed method is effective for dynamic and transient stability of power system.

이동 열원을 고려한 전자빔 용접의 유한요소해석

조해용,정석영,김명한,조창용,이제훈,서정 한국레이저가공학회 2001 한국레이저가공학회지 Vol.4 No.1

Simulation on the electron beam welding of Al 2219 alloy was carried out by using commercial FEM code MARC, which encounters moving heat sources. Due to axisymmetry of geometry, a half of the cylinder was simulated. A coupled thermo-mechanical analysis was carried out and subroutine for heat flux was substituted in the program. The material properties such as specific heat, heat transfer coefficient and thermal expansion coefficient were given as a function of temperature and the latent heat associated with a given temperature range is considered. As a result, the proper beam power is 60kVX60mA and welding speed is 1~1.5 m/min. The residual stress in the heat-affected zone as well as the fusion zone does not increase. It is necessary to use jigs for preventing distortion of cylinder and improving weld quality.