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.

생체분해성 고분자를 이용한 사시수술용 제형개발 및 효용성에 대한 연구

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

A new device, muscle clamping system was developed to facilitate exact quatifying technique A strabismus surgery, and reduce the risk of complications. The device is composed of a lower fixing body with three jaws and an upper supporting body. They are used to clip an extraocular muscle and fix it to the sclera with a single bite. Superior rectus recession on 16 rabbit eyes were performed with this new device. Conjunctival injection, muscle adhesion strength, and light microscopic findings were examined at 1, 2, 4 and 8 weeks postoperatively. The Conjunctival injection were minimal, adhesion power ranged from 420 to 600 gram gravity, which is sufficient in withstand the normal pull of human extraocular muscle. In microscopic exam, some Inflammatory cells and fibrosis were found. The new device was technically easy, fast, and accurate, so it may be useful in stabismus surgery.

Composite Skyrme model with the Atiyah-Manton Ansatz

Chung, Bok Keun,Lee, Byung Koo,Nam, Soon Keon 서울대학교 이론물리학연구센터 1995 연구논문집 Vol.4 No.-

Remarks on Lower Bounds of the Slope Parameter

Chung, Bok-Keun 慶熙大學校 1980 論文集 Vol.10 No.-

탄성산란 진폭함수의 허수부분(absorptive part)의 대수(logarithm)를 취한 다음 상대론적 운동량 제곱 변수에 대하여 미분한 이른바 slope parameter의 하한값(lower bound)을 공리적 양자장론(axiomatic quantum field theory)의 결과만으로부터 구할 수 있다. 최근에 s― 및 u― channel의 어느쪽에서나 s→∞일 때 이 하한값이 s^-5 In^-4 s라는 증명이문헌에 보고된 바 있으나 여기에서는 이 증명이 틀렸음을 보이고 있다. 더불어, 아직도 가장 좋은 하한값이 본인이 수년전에 구한 s^-5 In^-4 s이거나 u^-5 In-4 u(s→∞이거나 u→∞일 때)임을 보이고 있다.

Benzoxazolin-2-thione과 PAS의 Alkyl Ester과의 Mannich Base 합성 및 항균력에 관한 연구

정원근(Won Keun Chung),정상헌(Sang Hun Chung),정필근(Pil Keun Chung),윤원영(Won Yung Yoon),이남복(Nam Bok Lee) 대한약학회 1974 약학회지 Vol.18 No.4

Nine benzoxazolin-2-thione derivatives were synthesized as the potential antimicrobial substances. These compounds were tested for the antimicrobial activities using Staphylococcus aureus and Escherichia coli by way of tube dilution method. The three compounds of 1, II and VII inhibited the growth of S. aureus at the concentration of 1mcg/ml, and III, VI, VIII and IX exhibited considerable antimicrobial activities against S. aureus at the concentration of l0mcg/ml. As to the growth of E. Coli, VII VII and VIII inhibited at the concentration of 1mcg/ml. II,III and IV exhibited considerable antimicrobial activities against E. coli at the concentration of 10mcg/ml.

Impact of Guidelines on Clinical Practice : Intravenous Heparin Use for Acute Ischemic Stroke

Chung, Jong-Won,Kim, Beom Joon,Han, Moon-Ku,Ko, Youngchai,Lee, SooJoo,Kang, Kyusik,Park, Jong-Moo,Park, Sang-Soon,Park, Tai Hwan,Cho, Yong-Jin,Hong, Keun-Sik,Lee, Kyung Bok,Lee, Jun,Ryu, Wi-Sun,Kim, D Ovid Technologies Wolters Kluwer -American Heart A 2016 Stroke Vol.47 No.6

<P>Background and Purpose-Since its introduction, controversy has existed about the administration of intravenous heparin for the treatment of acute ischemic stroke. We studied trends in the intravenous heparin use during a 6-year time period and the potential influence of clinical guidelines in national language on intravenous heparin administration in Korea. Methods-On the basis of a prospective nationwide multicenter stroke registry, we collected data on patients with acute ischemic stroke who arrived within 7 days of symptom onset during the time period 2008 to 2013. We studied patient demographics, prestroke medical history, stroke characteristics, and stroke treatment. Data from a total of 23 425 patients from 12 university hospitals or regional stroke centers were analyzed. Results-The administration of intravenous heparin steadily decreased throughout the study period: 9.7% in 2008, 10.9% in 2009, 9.4% in 2010, 6.0% in 2011, 4.7% in 2012, and 4.3% in 2013 (P for trend < 0.001). The reduced intravenous heparin use was associated with moderate stroke severity, atrial fibrillation, and stroke of cardioembolic, other-, and undetermined etiology. In a multivariable logistic model, increase of 1 calendar year (odds ratio, 0.89; 95% confidence interval, 0.84-0.95; P < 0.001) and release of clinical practice guidelines in Korean (odd ratio, 0.74; 95% confidence interval, 0.59-0.91; P < 0.01) were independent factors associated with reduction in the frequency of intravenous heparin use. Conclusions-Use of intravenous heparin for acute ischemic stroke treatment has decreased in Korea, and this change may be attributable to the spread and successful implementation of regional clinical practice guidelines.</P>

Air Pollution Is Associated With Ischemic Stroke via Cardiogenic Embolism

Chung, Jong-Won,Bang, Oh Young,Ahn, Kangmo,Park, Sang-Soon,Park, Tai Hwan,Kim, Jae Guk,Ko, Youngchai,Lee, SooJoo,Lee, Kyung Bok,Lee, Jun,Kang, Kyusik,Park, Jong-Moo,Cho, Yong-Jin,Hong, Keun-Sik,Nah, H Ovid Technologies Wolters Kluwer -American Heart A 2017 Stroke Vol.48 No.1

<P>Conclusions-Our findings suggest that the short-term exposure to air pollutants is associated with cardioembolic stroke, and greater care should be taken for those susceptible to cerebral embolism during peak pollution periods. Public and environmental health policies to reduce air pollution could help slow down global increasing trends of cardioembolic stroke.</P>

경추 탈구에서 정복을 방해하는 추간판적 원인

정재윤,이근배,박유복 대한척추외과학회 1998 대한척추외과학회지 Vol.5 No.2

Study Design : Thirteen patients with cervical interlocked facets dislocation in whom closed reduction by skull traction was failed were evaluated about the patterns of ruptured disc fragment. Objects : To evaluate the causes of failure at closed reduction, and the relation between ruptured discs and interlocked facets, and the treatment results through an anterior approach. Summary of Literature review : In traumatic dislocation of the cervical facet joints, spinal cord or nerve roots injury associated with the ruptured disc fragment has been reported. However, there is few report evaluating the patterns of ruptured disc fragment as a cause of reduction failure. Materials and Methods : Between 1988 and 1997, thirteen patients were treated by anterior fusion with plate after complete removal of the intervertebral disc through anterior approach and reduction of interlocked facets by Oliveira method. They have been followed for an average of 36 months(range : 12-96 months). The interlocking was bilateral in seven cases and unilateral in six cases. We assessed the types of ruptured disc fragment by preoperative MRI and CT and the clinical and radiological results. Results : Ruptured disc fragment was found in all thirteen patients with interlocked facets dislocation. The patterns of ruptured discs were within the uncovertebral joints in 5 cases, posterioly under the posterior longitudinal ligament in 3 cases, anteriorly under intact anterior longitudinal ligament in 3 cases and combined under the anterior and posterior longitudinal ligament in 2 cases. The displacement of ruptured disc fragment were seemed to be the cause of failure in closed reduction. Conclusions : Intervertebral disc injury should be evaluated carefully with MRI and CT in the lower cervical interlocked facet dislocations before trial of reduction or decision makings of treatment.

점용접부의 피로강도 평가에 관한 연구

鄭鎭成,金英勳,李龍福,朴永勤 弘益大學校 科學技術硏究所 1997 科學技術硏究論文集 Vol.8 No.-

Spot welding has been used in the sheet metal joining processes because of its high productivity and convenience. In this study, effects of welding conditions on the fatigue life of spot welded joint and prediction of its fatigue life based on fracture mechanics theory of spot welded joint have been investigated. Fatigue tests were conducted with the tensile-shear specimens using cold rolled steel sheets. Fatigue life of spot welded joint was predicted and compared with experimental results. The experimental results are summarized as follows : 1. The static strength increased due to the increase in welding current, but the fatigue strength decreased while welding current being excessively increased. Therefore, the fatigue strength of spot weld was not proportional to the static strength. 2. Fatigue life of spot welded joint cannot be predicted accurately using the prediction methods proposed by Pook nor Findley. Therefore, it is necessary to consider stress index parameter method proposed by Kurath. 3. It is found that FEM analysis is powerful approach to evaluate the fatigue life of tensile shear spot welded joints with different geometry.

감마선(^60Co) 조사에 의한 항진균 세균의 돌연변이체 유도

정혜영,이영근,김재성,조규성,이영복 한국환경농학회 2002 한국환경농학회지 Vol.21 No.3

항진균 세균의 특성 및 기능변화 가능성을 조사하기 위하여 버섯폐배지, 온천수, 해조류 및 삼림토양으로부터 식물병원성 진균에 대한 8 종의 항진균 활성 균주를 분리하였고 감마선(^60Co)을 이용하여 LD_95 에 돌연변이체를 유도하였다. Bactllus circulans K1, Burkholderia gladioli K4와 Bacillussubtilis YSl은 12 종의 식물병원성 진균에 대go 항진균 활성을 보였다. 이들 균주의 방사선감수성 조사결과 B. gladioliK4는 감마선에 대한 높은 감수성을 보였으며, D_10 값은 0.11kGy 였다. 감마선에 의해 유도된 Kl-1004와 YSl-1009는Botryosphaeria dothidea에 대해 항진균 활성이 증가되었다. B.subtilis YS1의 돌연변이체인 YSl-1006과 YS1-1009는 tebuconazol과 copper hydroxide에 대해 농약 저항성을 나타냈다. SAR535, SAR5108 과 SAR5l18 돌연변이체는 야생형 균주인 Streptomyces sp. SAR01에 비해 5 종의 식물병원성 진균에 대해 항진균 활성이 없었다. 연구결과, 방사선을 이용하여 다양한 기능의 돌연변이체 유도가 가능하였다. 이를 이용하여 항진균 활성 관련 유전자 연구 및 균주개량이 가능할 것으로 사료된다. In order to evaluate the antifungal activity of bacteria against plant pathogenic fungi, 8 bacteria were isolated from mushroom compost, hot spring, seaweed, and forest soil and mutants from them were induced by LD_(95) gamma radiadon(^(60)Co). Bacillus circuluns K1, Burkholderia gladioli K4 and Bacillus subtilis YS1 showed wide antifungal spectrum against 12 kinds of plant pathogenic fungi. From the radiation sensitivity test, R gladioli K4 was very sensitive to gamma radiation and its D_(10) value was 0.11 kGy. Antifungal activities of B. circulans K1-1004 and B. subtilis YS1-1009, which were induced by the radiation of ^(60)Co increased against Botryosphaeria dothidea. The mutant strains, B. subtilis YS1-1006 and B. subtilis YS1-1009 were resistant to tebuconazole and copper hydroxide. SAR535, SAR5108, and SAR5118 mutated from Streptomyces sp. SAR01 were antifungal activity deficient mutants against 5 kinds of plant pathogenic fungi compared to wild strain, so that they could be supposed to be model strains for studying antifungal mechanism. It is suggested that various functional types of mutants could be induced by gamma radiation and applied usefully.