고속회전 하는 정밀부품을 위한 연질/경질 코팅의 트라이볼로지적 특성에 관한 연구

오진규,정구현,김대은,유제환,김형재 한국공작기계학회 2003 한국공작기계학회 춘계학술대회논문집 Vol.2003 No.-

Recently, rotating elements which use mechanical and electrical systems have been utilized for high speed and accuracy to increase the performance. The most important thing to get a more reliable system is to understand the friction, wear and characteristics which has an effect on various coated surfaces. In this study, the tribological characteristics of various soft/hard materials were investigated by using a custom-built pin-on-reciprocator tester. From the experimental results, it was found that the friction coefficients of the soft material coated surfaces were lower under various normal loads due to thier self-lubricating ability and material transfer to the counter surface.

전립선 결절성 증식증의 미세구조의 변화

손형규,채종민,곽정식,손태중 慶北大學校 醫科大學 1991 慶北醫大誌 Vol.32 No.1

전립성 결절성 증식증의 발병기전을 형태학전으로 규명하고자 10례의 환자에서 적출된 전립선을 광학 및 전자현미경적으로 검색하였으며 전립선의 분비선과 간질조직의 증식정도를 알기 위하여 형태계측법을 시행하였다. 아울러 대조군으로 2례의 부검시 적출된 정상인 전립선을 같은 방법으로 검색하였다. 그 결과를 요약하면 다음과 같다. 대조군에서 전립선의 분비선 상피세포는 분비과립, lysosome,mitochondria,ER 및 Golgi장치가 풍부하였으며 간질조직의 평활근세포 및 섬유아세포는 세포소기관의 양이 빈약하였다. 결절성증식증에서는 분비선 상피세포는 분비과립과 lysosome이 약간 있었을뿐 세포소기관의 양이 적었다. 간질조직에서는 평활근세포 및 섬유아세포내의 세포소기관의 양이 증가되었다. 형태계측법에 의한 전립선의 분비선 대 간질조직의 비는 대조군에서 0.28±0.04이었으며 결절성 증식증에서는 0.10±0.03으로 간질조직이 증가되었다. 이상의 성적으로 보아 전립선의 결절성 증식증은 일차적으로 간질조직의 증식에 의해 일어나는 질환으로 인정된다. Normal and prostatic nodular hyperplasia were studied by quantitative light microscopic measurements and electron microscopy. Two cases of normal prostate obtained from the autopsy and ten cases of nodular hyperplasia were examined. Electron microscopically, glandular lining cells of the normal prostate showed abundant secretory granules, lysosomes, endoplasmic reticulums, mitochondria, and Golgi apparatus. Smooth muscle cells and fibroblasts had a few cell organelles. the epithelial cells of the hyperplastic glands demonstrated less cell organelles. However, smooth mucle cells and fibroblasts revealed abundant cell organelles. On the morphometry, the ratio of gland to stromal tissue were 0.28±0.04 in control group and 0.10±0.03 in nodular hyperplasia. According to the above results, it is suspected that the nodular hyperplasia is primarily a stromal disease.

Mirizzi 증후군의 변형된 분류와 치료

김형철,강길호,채만규,김성용,백무준,이문수,박상흠,이문호,김창호,송옥평,조무식,박희주 순천향의학연구소;Soonchunhyang Medical Research Institute 2000 Journal of Soonchunhyang Medical Science Vol.6 No.1

Purpose : The Mirizzi syndrome is relatively rare and preoperative diagnosis of this disease is difficult. In 1978, Morelli suggested the subclassification of the Mirizzi syndrome into acute or chronic form. We experienced 5 cases of acute form. We analysed clinical features, preoperative radiologic findings and operative findings of 18 cases including acute forms which were diagnosed as Mirizzi syndrome and should suggest the modified classification of Mirizzi syndrome for choice of appropriate treatment. Method : From January 1995 to December 1998, 18 cases, of which 8 cases were diagnosed at Soonchunhyang University Chunan Hospital, and 10 cases were reported in the Korean Journal were retrospectively analysed with regard to clinical features, preoperative radiologic findings and operative findings. According to the clinical features, whole cases were divided into type Ⅰ(acute form) and type Ⅱ(chronic form) and then each type of cases were subclassified according to preoperative radiologic findings and operative findings. Results : Of 18 cases there were 5 cases in type Ⅰ(27.8%), 13 cases in type Ⅱ(72.2%). Type Ⅱb was most common. Type Ⅰa cases were treated only with cholecystectomy. We applied cholecystectomy, T-tube choledochostomy and patch technique in type Ⅰb and thpe Ⅰc cases. Cholectystectomies including removal of gallstones and internal drainage procedures were done in type Ⅱ chronic forms. Conclusion : The acute form(Type Ⅰ) of Mirizzi syndrome was suggested by Morelli might be subclassified into typeⅠa,Ⅰb and Ⅰc following the presence of the necrotic defect in common hepatic duct. Through the modified classification of Mirizzi syndrome based on clinical feature, preoperative radiologic findings and operative findings, we can choice appropriate treatment.

관동맥풍선시술중 혈전동반 병변에 대한 구조치료(Rescue Utilization)로서의 Abciximab(ReoPro^(�)의 효과

두영철,채경수,최종형,허필석,송관욱,홍경순,박대균,한규록,오동진,유규형,임종윤,고영박,이광학,이영 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.12

개에서 심실 조율부위 및 조율주기에 따른 혈역학적 변화

김희열,김재형,노태호,김종진,진승원,유기동,이만영,채장성,홍순조,최규보 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.9

장중첩증을 동반한 맹장 지방종 1예

홍의실,나병규,김민옥,유일영,채지영,채희복,윤세진,이상전,송형근,박길선,정현용 충남대학교 의과대학 의학연구소 2002 충남의대잡지 Vol.29 No.2

대장 지방종은 주로 우측 결장에 호발하고 특히 회맹판 부위와 맹장 부위에 호발한다. 또한 50~60대에 빈도가 높고 증상이 있는 환자에서 장중첩증이 높게는 40~50%에서 보고되고 있어 성인 장중첩증의 원인으로 중요한 비중을 차지한다. 특히 성인 장중첩증 및 장폐쇄의 중요 원인인 악성 종양과 임상 양상이 유사하여 감별진단이 중요하다. 저자들은 반복적인 복통을 주소로 내원한 환자에서 맹장의 4×5㎝의 점막하 지방종이 말단 회장부위와 반복적인 장중첩중이 발생했던 1례를 부분 절제술로 치료하여 양호한 임상 경과를 경험하였기에 문헌 고찰과 함께 보고하는 바이다. Lipomas are one of the most common benign nonepithelial tumors of the colon which are often detected incidentally by radiologic investigation or on operation. These tumors are usually without specific symptoms. Colonic lipomas occur most often in the right colon, particularly in the ileocecal valve and the cecum. Most patients are asymptomatic. but tumors larger than 2 cm tend to produce a change in bowel habit. abdominal pain. rectorrhagia and complications including luminal obstruction or intestinal intussusception. Diagnosis can be made by colonoscopy abdominal CT. MRI, or barium enema. We report a case of lipoma of the cecum that originated in the submucosa and presented as a intussusception in a 50-year-old woman with a brief review of the literature.

심실 조기 수축의 발생 부위 및 연결 간격의 차이에 따른 혈역학적 변화

진승원,김재형,노태호,조은주,김희열,이만영,김종진,박준철,채장성,홍순조,최규보 대한순환기학회 1999 Korean Circulation Journal Vol.29 No.7

필러의 종류가 UTMA 계 광중합형 복합레진의 강도에 미치는 영향

배태성,최진용,최규형,채민수 大韓齒科器材學會 2000 대한치과재료학회지 Vol.27 No.3

This study was performed to evaluate the effect of resin and filler type on the strength of light-activated composites. Experimental composites were prepared using the four types of urethane tetramethacrylate monomers(HM-4M, TM-4M, XY-4M and DC-4M) and three different shapes of silica fillers. Cylindrical specimens of 3㎜ in diameter and 6㎜ in length and rectangular specimens of 2×2×24㎜ were prepared for the compressive test and 3-point bend test, respectively. All specimens were immersed in distilled water at 37℃ for 24 hours. Compressive and 3-point bend tests were carried out at a crosshead speed of 0.5 ㎜/min and fracture surfaces were observed with scanning electron microscope. The results obtained were summarized as follows : 1. When the size distribution of fillers was same, composites containing the spherical fillers showed the relatively higher loading rate of fillers and compressive strength than those containing the crushed fillers. 2. Compressive strength values of the composites based on UTMA monomers containing the aliphatic UTMA monomers (HM-4M and TM-4M) showed the relatively higher strength values than those of the composites based on UTMA monomers containing the aromatic or cyclohexane ring in their chemical structure(XY-4M and DC-4M). 3. The compressive and transverse strength values of UTMA-based composites were higher than those of Bis-GMA-based composites. 4. According to the microscopic observation of fracture surfaces, composite failure developed along the matrix resin and resin/filler interface region.

데페록사민 전처치가 토끼 심근경색 크기의 감소에 미치는 효과

양관모,오동렬,박승현,박규남,이원재,김형국,황두영,최승필,채장성 대한응급의학회 1998 대한응급의학회지 Vol.9 No.4

Background: Reperfusion of ischemic myocardium has been postulated to result in a specific oxygen radical mediated tissue injury. Iron may liberate during ischemia and we hypothesized that administration of the iron chelator, deferoxamine during ischemia would result in improved recovery after postischemic reperfusion. Purpose: To test whether iron-catalyzed processes contribute to myocardial necrosis during ischemia and reperfusion, deferoxamine was administered to block iron catalyzed hydroxyl radical formation in rabbits. Methods: Eleven rabbits were divided into two groups : control group (n=5) and deferoxamine pretreatment group (n=6). The left circumflex coronay artery was ligated for 30 minutes and reperfused for 180 minutes. Area at risk (AR) was measured by non-stained area with methylene blue injection into left atrium after left circumflex coronary artery ligation. Infarct size was measured by weighing after triphenyltetrazolium chloride staining. Heart rate was measured using electrocardiographic recording and systemic blood pressure was monitored by pressure transducer connected to the catheter in the left ventricle. Results: 1. There was no significant difference of heart rate and blood pressure in deferoxamine pretreatment group compared with control group. 2. There was significant decrease of serum iron concentration after continuous infusion of deferoxamine compared with serum iron concentration before ligation of coronary artery(P<0.05). 3. There was no significant difference of area at risk between control and deferoxamine pretreatment group. 4. Area at necrosis to area at risk was significantly reduced in deferoxamine pretreatment group compared with control group(P<0.05). The results suggest that deferoxamine infusion prior to coronary artery occlusion has a significant benefit in reducing infarct size in this model.

간 세포암에서 VEGF, TGF-β1, b-FGF 발현의 의의

김성용,남충현,주종우,채만규,백무준,이문수,김형철,안현철,김홍수,김창진,김창호 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.1

Purpose: Angiogenesis is important for the proliferation and the metastasis of solid tumors. The growth of a solid tumor is widely recognized to depend on the process of neovascularrozation. Without angiogenesis, tumors cease to grow beyond even a few milimeters in diameter. It has been shown that tumor vascular density is an independent prognostic marker in several types of human tumors and is known to correlate with poor prognosis. To date, many angiogenic factors have been identified, such as transforming growth factor-α(TGF-α), transforming growth factor-β(TGF-β), fibroblast growth factor family(FGF), vascular endothelial growth factor(VEGF), platelet derived endothelial cell growth factor(PD-ECGF), tumor necrosis factor-α(TNF-α), and angiogenin. Hepatocellular carcinoma(HCC) is the second most common tumor in Korean males and is known as a typical hypervascular tumor with frequent portal vein invastion. The authors identified the expreesion of VEGF, TGF-β1, and b-FGF in HCC specimens and evaluated the relationship between these growth factors and the clinicopathologic characteristics of HCC. Method: We reviewed the medical records of 30 patients who were diagnosed as hepatocellular carinoma treated with hepatic resection between January 1994 and December 1998 in Soonchunhyang University Chunan Hospital. The selection of the cases was decided according to the condition of paraffin block fixation. The prognostic factors such as age, sex, tumor size, concentration of serum α-fetoprotein, presence of liver cirrhosis, presence of tumor emboli in portal vein, TMN stage, amount of transfusion during the operation, hepatitis B virus(HBV) infection, and Edmonson-Steiner(E-S) grade were investigated. Relationship between the prognostic factors and the immunopathologic expression of the TGF-β1, b-FGF, and VEGF was examined. Result: Thirty patients (24 males, 6 females) were included in the current study. The patient's mean age was 50.6 years and the age ranged from 36 to 65 years. The mean size of the tumor was found to be 5.2cm. All the patients were follewed up for 7 to 63 months. Child's classification A patients were 23(76.7%)cases, B patients were 7(23.3%)cases, and C was none. Immunohistochemical staining of HCC tumor mass in VEGF expression patients were 17(56.7%), b-FGF expression patients were 10(33.3%), and TGF-β1 expression patients were 10(33.3%). VEGF expression or more than one positive expression among the three factors correlated with tumor size and the stage of HCC but did not correlated with other clinicopathological characteristics. TGF-β1 and b-FGF did not correlate with any clinicopathological characteristics. Conclusion: The results suggest that the expression of VEGF or more than one positive expression among the three factors in HCC cells may be a significant prognostic factor of HCC.