SF_6 절연파괴에 미치는 도전성 파티클의 영향

구자윤,이방욱 漢陽大學校 工學技術硏究所 1996 工學技術論文集 Vol.5 No.1

In this work, particle effect on the breakdown in pressurized SF6 was systematically investigated using Cu particle fixed on the parallel electrode monitoring system. For this experiments, various size particles were prepared and D.C Voltage and Lightning Impulse voltage were applied to the system as a function of gas pressure from 1 atm to 5 atm. At D.C test, it was revealed that particle length could affect the breakdown voltage seriously and corona stabilization effect could influence the breakdown voltage at some critical pressure and streamer corona was main discharge mechanism on the breakdown in SF6. At L.I test, breakdown voltages were affected depending on the the polarity of applying impulse voltage. It was noticed that the negative polarity could reduce the insulation strength much greater than the positive polarity and breakdown voltage could not be raised by increasing gas pressure above the critical value.

Human Serum Albumin에 대한 단세포군 항체의 생성, 특성분석 및 microalbuminuria 검색을 위한 sandwich ELISA의 개발에 관한 연구

구자욱,고광욱,고재경 한양대학교 의과대학 1992 한양의대 학술지 Vol.12 No.1

Alumin of a variety of species has been the subject of extensive studies by protein chemists and immunologists for over 3 deades. Human serum albumin (HSA) is the most abundant protein in plasma. It is a nonglycosylated protein consisting of a single polypeptide chain of 585 amino acids with 34 cystive residues. The molecule contains 9 serial double loops formed by 17 disulfide bridges arranged as 3 repeat units or domains. Since polyclonal antibodies bind to almost all antigenic determinants of antigen, the experiments base4d on polyclonal antibodies yielded frequently low-titre, of broad specificity, and are not completely reproducible, although the heterogeneity of fine specificity could be minimized by affinity chromatography on fragments of the immunogens. Recently, the development of hybridoma techniques has made it possible to produce a large amount of homogenous and specific anti-protein antibody which reacts with a single epitope of antigen. Diabetic nephropathy is the major cause of the increased mortality in insulin-dependent diabetes mellitus (IDDM), affecting over 40% of these patients. Recent studies have shown that an increased urinary albumin excretion rate (microalbuminuria) in IDDM patients is a good predictor of the development of diabetic nephropathy. The possibility that therapeutic intervention instituted at this early stage of the disease might reverse, arrest or at least slow its progression to late and irreversible stages promotes the necessity to develop a screening test for microalbuminuria. Microalbuminuria can be measured by radioimmunoassay(RIA), nephelometric laser, immunoturbidimetry and enzyme linked immunosorbent assay(ELISA). However, RIA has some disadvanges such as isotope-related health hazards, and expense of equipment used to measure gamma-emitting isotope. The aims in this study were to produce monoclonal antibodies against HSA and to develop a simple, rapid, and sensitive sandwich ELISA using anti-human albumin monoclonal antibodies for detecting microalbuminuria. Four monoclonal antibodies(MHA-1, MHA-2, MHA-3, and MHA-4) which reacted selectively against HSA were produced by hybridoma technology. Isotype of each monoclonal antibody was found to be IgG₁. All monoclonal antibodies except MHA-1 were species-specific which were demonstrated on ELISA and immunoblotting. Since MHA-4 reacted with albumin in only nonreducting condition, it was suggested that this antibody recognized the conformational epitope of the albumin. Utilizing ingibition ELISA, it was speculated that these four antibodies recognized respectively 4 different epitopes of albumin and among those epitopes, epitopes of MHA-2 and MHA-3 same or located very approximately. Sandwich ELISA using two monoclonal antibodies(MHA-4 as capture antibody and MHA-2 as detector antibody), which reacted with different epitopes, were developed to detect microalbuminuria. Dynamic range of this assay was from 30 to 5000㎍/1 and its lowere limit of detection was 30㎍/1, corresponding to 1.5ng of albumin per well. The intra-assay and the inter-assay coefficient of variation were 3.3-4.0% and 6.8-8.0%, respectively. Analytical recovery ranged from 92 to 103%. Concentrations of 84 urine samples were measured by the sandwich ELISA and competitive RIA. Correlation between two assays was good(r=0.983, p<0.005) over a range of albumin concentration tested. Albumon excretions in 24 hour urine samples from non-insulin-dependent diabetes mellitus(NIDDM) patients (mean 16.7mg/day, n=39, 8yr duration) were significantly increased (t=2.53, p=0.015) as compared with those from healthy subjects(mean 5.6mg/day). However, 24 hour urine albumin excretions in IDDM patient(mean 11.1mg/day, n=25, 6.8yr duration) werer not significantly different from those in normal control(t=1.16, p=0.26). The 24 hour urine albumin(mg/day) correlated well with the urine albumin/creatinine ratio(r=0.816, p<0.005) on log data. This study indicates that this newly established sandwich ELISA is found to have good analytical characteristics, outstanding in its specificty, sensitivity, accuracy, and precision, and is suitable and easily accessable for detection of microalbuminuria in clinical medicine.

Renal Interstitial Fibrosis and Angiotensin Inhibition

( Ja Wook Koo ) 대한전해질,혈압학회 2006 Electrolytes & Blood Pressure Vol.4 No.1

혈청 CA-125, 초음파 및 양전자방출단층촬영술을 통한 골반 종물의 감별진단

구자성 ( Ja Seong Koo ),김영태 ( Young Tae Kim ),김성훈 ( Sung Hoon Kim ),김재욱 ( Jae Wook Kim ),김재훈 ( Jae Hoon Kim ),박용원 ( Yong Won Park ),김복자 ( Bok Ja Kim ),남은지 ( Eun Ji Nam ),윤미진 ( Mi Jin Yun ) 대한산부인과학회 2005 Obstetrics & Gynecology Science Vol.48 No.8

비특이성 식도운동장애 환자에서 위식도역류질환의 유병률

구자설(Ja Soul Koo),송치욱(Chi Wook Song),조영직(Young Gik Jo),고동욱(Dong Wook Koh),손수민(Soo Min Shon),김용식(Yong Sik Kim),정록선(Rok Son Choung),진윤태(Yoon Tae Jeen),전훈재(Hoon Jai Chun),김창덕(Chang Duck Kim),류호상(Ho Sang R 대한소화기기능성질환·운동학회 2001 Journal of Neurogastroenterology and Motility (JNM Vol.7 No.2

N/A Backgroud/Aims: The nonspecific esophageal motility disorder (NEMD) has been reported to be related to gastroesophageal reflux disease (GERD) in some cases. However, the pathophysiologic mechanism of NEMD has not been estabilished. The aim of this study was to assess the prevalence of esophagitis and gastric acid reflux following abnormal contractions in patients with NEMD. Methods: 122 NEMD patients were enrolled (76 male and 46 female) and their endoscopic findings and 24 hour esophageal Ph data were compared with 24 healthy subj ects. The abnormal contractions were classified as 1) non-transmitted con-traction, 2) low amplitude contraction, 3) non-transmitted and low amplitude contraction, and 4) others. Results: Among the 122 patients with NEMD, 62 patients (50.8%) had GERD, 53 patients (43.4%) had endoscopic reflux esophagitis, and 41patients (33.6%) had both. Acid exposed time studied by 24 hour Ph monitoring was more increased in NEMD patients than in healthy controls (7.48 ±10.68 vs 1.42 ±1.17), but there were no differences among abnormal contraction patterns. Moderate to severe reflux esophagitis were frequently seen in patients with combined abnormal contractions as the results of endoscopic findings. Pre-existing factors for the gastric acid reflux in NEMD patients were male and esophageal hiatal hernia. Conclusions: Large numbers of NEMD patients were found to have concurrent GERD in our study. However, the esophageal peristaltic dysfunction was more closely related to the severity of esophagitis rather than to the amount of refluexed gastric acid itself. (Korean Journal of Gastrointestinal Motility 2001;7:168-174)

위암 발생의 민감성과 RNase3 유전자 다형성과의 연관성

구자욱(Ja Wook Koo),강동백(Dong Baek Kang),박원철(Won Cheol Park),이영환(Young Hwan Lee),강인홍(In Hong Kang),채수천(Soo Cheon Chae),이정균(Jeong Kyun Lee) 대한외과학회 2010 Annals of Surgical Treatment and Research(ASRT) Vol.78 No.5

Purpose: RNase3 is a secretory ribonuclease, which is found in the eosinophilic leukocyte and involved in the innate immune system. Its cytotoxic activity is effective against a wide range of pathogens. We performed a case-control study to examine the relationship between RNase3 polymorphisms and the susceptibility of gastric cancer in Korean people. Methods: Blood sampling of stomach cancer and healthy persons groups were performed, Taqman in g.-550A>G, polymerase chain reaction-restriction fragment length polymorphism in g.371C>G, and high-resolution melt in g.499C>G were analyzed. The three single nucleotide polymorphisms g.-550A>G, g.371C>G, and g.499C>G in RNase3 and their haplotypes were analyzed. Results: The genotype and allele frequencies of RNase3 g.-550A>G and g.371C>G were not significantly increased in susceptibility of gastric cancer than control group. But, RNase3 CC genotype was associated with a significantly increased susceptibility of gastric cancer than control group (P=0.002). Also, RNase3 CC genotype was more specifically associated with a significantly increased susceptibility of middle and lower gastric cancer than upper gastric cancer (P=0.002). In haplotype of RNase3 SNP g.-550A, g.371G, and g.499C, there was significantly susceptibility of gastric cancer (P=0.004), and more specific influence on middle and lower gastric cancer than upper gastric cancer (P=0.006 vs 0.054). Conclusion: RNase3 g.499C>G polymorphism may influence gastric cancers, and have a more specific influence on middle and lower gastric cancer rather than upper gastric cancer. But RNase3 g.-550A>G, g.371C>G polymorphisms need careful interpretation and confirmation in more larger studies.

서울 동북부지역에서 산발적으로 발생한 Yersinia Pseudotuberculosis 감염에 대한 연구

구자욱,백인기,조종래,김의종 대한감염학회 1994 감염 Vol.26 No.1

Yersinia pseudotuberculosis infection had been reported in mountainous area of Japan and named as Izumi fever, and untreated drinking water was one of main source of this infection. Seoul, the capital city of Korea is now heavily populated and there is increased concern of environmental pollution. Some people is afraid of drinking tap water because of possible water pollution in Han river, the main sourse of tap water in Seoul. Many people go to mountains to get their drinking water from springs thinking that mountain spring water might be free from pollution. More than 140 patients who were clinically suspected as yersiniosis visited Sanggye Paik hospital in May, June, July, and November, 1993, which is located at northeastern part of Seoul near mountainous area. Y. pseudotuberculosis infection was confirmed by stool culture in 15 pediatric patients using cefsulodin irgasan novobiocin (CIN) agar as the selective media. Analysis of serogroups showed that 5 strains belonged to group 4, 19 group 5, one group 6, and one was unknown. All patients had history of drinking untreated cold water from springs in mountainous area several days prior to the onset of symptoms. We successfully isolated Y. pseudotuberculosis from 11 spring waters among 21 of suspicious mountain springs at different locations using filtration and culture technique after KOH treatment. We think that untreated spring water is one of the main sources of sporadic Y. pseudotuberculosis infection in Seoul and children should not drink untreated spring water to eradicate this water borne infectious disease.

Representation of a Conceptual Design for a Rectilinear Motion Polymer Actuator

Ja Choon Koo,Kwang Mok Jung,Jong Kil Park,Jae Do Nam,Young Kwan Lee,Jae Wook Jeon,Hyouk Ryeol Choi 대한전기학회 2007 International Journal of Control, Automation, and Vol.5 No.4

A number of different alternative actuation methods have been under active development for some specific applications where the traditional electromechanical actuators are difficult to apply. Recently, many of these substitutes are trying to employ new smart materials like electroactive polymers. However most of the polymeric materials are flexible and vulnerable so that they normally can not sustain external forces. Although the materials have shown a good potential to be used for alternative actuation mechanisms, no tangible industrial application is yet presented because of the reason. A conceptual design for a rectilinear motion actuator using dielectric elastomer is presented in this article. The introduced design concept might enable to produce fairly controllable rectilinear motions for various applications and the presented prototype actuator system is fully packaged in a small unit and controlled by a standard communication interface.

십이지장 팽대부 주위암의 췌십이지장절제술

구자윤(Ja Yun Koo),이우정(Woo Jung Lee),노성훈(Sung Hoon No),김명욱(Myung Wook Kim),김병로(Byung Ro Kim),민진식(Jin Sik Min),이경식(Kyung Sik Lee) 대한외과학회 1992 Annals of Surgical Treatment and Research Vol.43 No.4

Clinical features of active tuberculosis that developed during anti-tumor necrosis factor therapy in patients with inflammatory bowel disease

( Jang Wook Lee ),( Chang Hwan Choi ),( Ji Hoon Park ),( Jeong Wook Kim ),( Sang Bum Kang ),( Ja Seol Koo ),( Young Ho Kim ),( You Sun Kim ),( Young Eun Joo ),( Sae Kyung Chang ) 대한장연구학회 2016 Intestinal Research Vol.14 No.2

Background/Aims: Anti-tumor necrosis factor (TNF) therapy for active ulcerative colitis (UC) and Crohn`s disease (CD) is associated with increased risks of tuberculosis (TB) infection. We analyzed the incidence and clinical features of Korean patients with inflammatory bowel disease (IBD) who developed active TB during anti-TNF therapy. Methods: Ten cases of active TB developed in patients treated with infliximab (n=592) or adalimumab (n=229) for UC (n=160) or CD (n=661) were reviewed. We analyzed demographics, interval between start of anti-TNF therapy and active TB development, tests for latent TB infection (LTBI), concomitant medications, and the details of diagnosis and treatments for TB. Results: The incidence of active TB was 1.2% (10/821): 1.5% (9/592) and 0.4% (1/229) in patients receiving infliximab and adalimumab, respectively. The median time to the development of active TB after initiation of anti-TNF therapy was three months (range: 2-36). Three patients had past histories of treatment for TB. Positive findings in a TB skin test (TST) and/or interferon gamma releasing assay (IGRA) were observed in three patients, and two of them received anti-TB prophylaxis. Two patients were negative by both TST and IGRA. The most common site of active TB was the lungs, and the active TB was cured in all patients. Conclusions: Active TB can develop during anti-TNF therapy in IBD patients without LTBI, and even in those with histories of TB treatment or LTBI prophylaxis. Physicians should be aware of the potential for TB development during anti-TNF therapy, especially in countries with a high prevalence of TB. (Intest Res 2016;14:146-151)