가속수명실험을 이용한 케이블 절연재료의 수명특성에 관한 연구

남창우,이규철,박홍태,이태식,김경석 울산대학교 1997 공학연구논문집 Vol.28 No.1

본 연구는 고체절연재료의 수명예측의 일환으로서 가속수명실험을 통해 얻은 수명데이터의 통계학적 처리방법과 복합 스트레스와 수명과의 상호관계를 규명하기 위한 수명모델을 제시하고 있다. 가속수명실험을 통해 얻는 수명데이터는 와이블분포에 적용하고, 최소자승법과 최우추정법을 이용하여 와이블분포함수의 모수를 추정하였다. 또한 제시된 수명모델의 상수를 추정하여 복합스트레스와의 관계를 규명함으로써 수명모델의 타당성을 입증하였다. 추정결과, 주위온도와 인가전압이 상승함에 따라 수명은 현저히 짧아지고, 수명모델의 상수는 복합스트레스에 크게 의존하는 것으로 나타난다. 따라서 본 연구에서 제시된 수명모델은 고체절연재료의 수명을 나타내는데 적당한 것으로 나타났다. This paper suggests the statistic method for a lifetime estimation of solid insulating materials using the data obtained from accelerated aging test has been performed to obtain the lifetime data. The multi-stress including thermal and electrical stress has been applied to accelerate the degradation of insulating materials. The Weibull Cumulative Distribution Function has been used to treat statistically the lifetime data. Using the lifetime model of this study, we estimated the lifetime constants to show the relationship between the lifetime and the applied multi-stress. It has been shown that the lifetime model agrees well with the lifetime of solid insulating materials.

순천향대학 천안병원에 내원한 알레르기환자의 특성

황규윤,남해선,,안현철,박준수 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.1

This study was designed to evaluate gencral features related to allergy of allergic patients living in northern and western Chungchungnamdo, visited to an allergic unit in Soonchunhyang University Chunan Hospital during August 1998 to July 2000. Three hundred allergic patients were enrolled. Among them, 87.7% were outpatients and were analysed for the study. Demographic variables as well as resident living conditions and immunologic results were assessed. Overall IgE, house dust, Dermatophagoides farinae (Df), and Dermatophagoides pteronyssinus (Dp) antibody were assessed using MAST-CLA in 263 outpatients. Relations between allergens and age, sex, and living conditions were evaluated by chi-square tests. Mean age was 21.0 ± 17.3 year-old and male accounted for 59.3% in total subjects. Among them, 52.0% lived in an apartment and 65.3% were from urban area near Chunan and Asan city. Admission rate of allergic patients was 12.3%. The positive rates of total IgE, house dust, Df, and Dp were in 55.1%. 19.0%, 30.0%, and 29.3% in outpatients, respectively. No significant relations between allergens and sex. living home, and region were observed (P>0.05). Adolescents showed significantly higher positive rate of total IgE (P=0.02). Our data suggested that residential environment may not be a significant factor of main causative allergens in northern and western Chungchungnamdo. However more controlled study should be required to elucidate the relations between living environments and major causative allergens in this area.

급성 골수성 백혈병과 동반된 급성 발열성 호중구성 피부병 1예

오창남,강인경,최규철 조선대학교 1993 The Medical Journal of Chosun University Vol.18 No.2

Acute febrile neutrophilic dermatosis (Sweet's syndrome) is characterized by painful erythematous plaques, fever, leukocytosis and a dense dermal infiltrate of neutrophils at the site of skin lesion. We presented a case of acute febrile neutrophilic dermatosis in acute myelogenous leukemia in 24-year-old male. Painful and brownish noduloplaques appeared on the face after chemotherapy for acute myelogenous leukemia. Microscopic examination of biopsy specimen disclosed a dense dermal infiltrate composed mainly of neutrophils. Also there were many nuclear dust, but no evidence of true vasculitis.

플라즈마를 이용한 유리섬유강화 복합절연재료의 표면처리에 관한 연구

이규철,남창우,김희대,황영한,김경석 울산대학교 1997 공학연구논문집 Vol.28 No.1

본 연구에서는 에폭시계 복합 절연재료 Glass-cloth/Epoxy 의 계면 접착특성을 향상시키기 위하여 표면처리 조건에 따라 각각 복합 절연재료를 제작하였고, 전기·기계적특성의 상관관계를 다음과 같은 실험을 행하여 비교하였다. Glass의 젖음의 정도를 평가하기 위하여 표면처리 조건에 따라 주위온도 80[℃]에서 접촉각을 측정하였고, 주위온도 및 인가전압을 변화시키면서 비유전율(εr), 유전정접(tanδ) 및 전기적 절연강도를 측정하였다. 기계적 특성을 측정한 후에 파단면의 형상을 SEM으로 분석, 검토하였다. 실험 결과, (1) 주위온도가 상승함에 따라 비유전율 및 유전정접은 증가하였고, 전기적 절연강도는 감소하였으며 플라즈마 처리함으로서 전기·기계적특성은 전반적으로 향상되었다. (2) 접촉각 측정 주위온도가 80[℃]일 때, 표면처리 조건에 따른 젖음성은 각각 다르게 나타났고 플라즈마 처리효과는 표면세정, 미세요철, 표면대전 및 젖음성의 감소와 같은 복합효과로 볼 수 있다. (4) 전기·기계적특성의 관점에서 복합 절연재료의 경화온도가 80[℃]일 때, Glass-cloth/Epoxy복합 절연재료의 최적처리시간은 3분 정도로 나타났다. The Glass-cloth/Epoxy composite insulating materials for this study have been prepared with several different surface treatmenttechniquen such as untreatment ultrasonic treatment and plasma treatment, and their electrical and mechanical characteristics have been compared each other. It has been found that plasma-treated glass has the smallest contact angle with a drop of epoxy. The plasma-treated composite materials have superior dielectric strength and mechanical tensile-strength compared to the materials subjected to other surface treatments. Also, the experiment showed that there exists an optimum plasma treatment duration for improving the interfacial characteristics of the composite insulating materials. The optimum plasma treatment durations are about 3 minutes for Glass-cloth/Epoxy at 80[℃]. Longer plasma treatment has been appeared to degrade the interfacial characteristics.

일부전자파 발생제품 사용에 따른 인체의 신체자각증상 조사

이규수,남철현 대한보건협회 2002 대한보건연구 Vol.28 No.3

This study was conducted to examine harmful effect on health and preventive attitude by the use of equipments which generate electronic wave in order to provide basic data for development of preventive education program 2,000 people, who lived in five big cities and five small and medium cities, were selected ad subjects of this study. the data were collected from March 1, 2001 to August 31, 2001. The results of this study are as follows. According to the proportion of physical symptoms felt by the respondents due to the use of the electronic or electric products, 30.1% of them did not feel any symptom, while 20.4% of them felt headache 19.6% of the respondents felt dizzy and 11.1% felt migraine. 10.4% of them had amnesia, while 8.4% felt nausea. The physical symptoms displayed significant relationships with the variables of TV, cellular phone, electric game instrument, microwave oven, electric pad or blanket, vacuum cleaner, electric razer, electric tool, vessel washer, and hair drier. In the case of the proportion of physical symptom felt by those who visited medical institutions, 'headache' was 7.6% and 'digestive trouble' was 10.7% 'Lumbago' was 9.3%, while 'oral disease' was 8.7%. 'The other symptom' was 33.0% and 'no symptom' was only 5.4% These showed significant relationships with the variables of TV, cellular phone, computer, electric game instrument, microwave oven, electric pad or blanket, vacuum cleaner, air conditioner, electric razer, vessel washer, hair drier, and laser printer. Nowadays, it can be said that human beings can not live without electronic products. It is necessary to use them in order to enhance quality of life. Therefore, education and publicity concerning harmful affect of electronic wave on health is needed because people's opportunity of exposing to electronic wave is increasing. Especially, it is the demands of the times to provide information on knowledge of each equipment which generate electronic wave. The government, the product manufacturing companies, related social organizations, and education institutions must make efforts to develop the education program which is needed to make people have right knowledge and attitude..

장시간 불가피한 공복(fasting)후 인체의 내분비 변화 : 삼풍백화점 붕괴 사고후 구조된 3인의 증례 THREE CASES IN COLLAPSE OF SAMPOONG DEPARTMENT STORE

박규남,황주일,박조현,오동렬,이원재,오승택,김세경,김인철 대한응급의학회 1995 대한응급의학회지 Vol.6 No.2

The interactions between nutrition and the endocrine system are more intimate and complex that previously thought. Nutrition modulates secretion and activity of many hormones, as part of the stress adaptation process. Fasting, in particular, produces a number of important changes in the endocrine system, with teleological purpose of helping the body tolerate the lack of food ingestion. These changes are therefore beneficial and protective, although at times they may not appear to be that way. The endocrine changes of fasting mediate the metabolic response. We must emphasize that these changes are completely reversible when appropriate nutrition is established. These changes are as followes: 1) decreased insulin and increased glucagon levels, 2) decreased thyroid effect, 3) decreased sympathetic activity, 4) hypothalamic hypogonadism, 5) decreased growth, 6) altered glucocorticoid secretion and metabolism, 7) impaired mineralocorticoid response, 8) decreased ADH secretion and effect. We experienced three cases of involuntary prolonged fasting after collapse of Sampoong department store. They were released from collapsed field after 11(case Ⅰ), 13(case Ⅱ), 17days(case Ⅲ) respectively. In each case, the endocrine changes of plasma levels were as followes: decrease of cortisol in case Ⅰ, increase of GH in case Ⅱ, decrease of free T3, T3, cortisol and increase of reverse T3, insulin in case Ⅲ. Each one did not show the same endocrine changes of plasma levels. But we think these changes of fasting are beneficial in metabolic response of human.

전국 단위 감시체계의 현황과 전망

강성규,안연순,지영구,김형옥,하미나,권호장,백남종,김성아,홍윤철,김재용,강대희,정혜선,하은희 대한산업의학회 2001 대한직업환경의학회지 Vol.13 No.2

Effects of epigallocatechin gallate on CoCl_(2)-induced apoptosis in PC12 cells

Yang, Kyu-Ho,Mo, Hyun-Chul,Choi, Nam-Ki,Kim, Seon-Mi,Kim,Won-Jae 大韓小兒齒科學會 2006 大韓小兒齒科學會誌 Vol.33 No.1

Neuronal apoptotic events, consequently resulting in neuronal cell death, are occurred in hypoxic/ischemic condition. This cell death has been shown to be accompanied with the production of reactive oxygen species (ROS), which can attack cellular components such as nucleic acids, proteins and phospholipid. However, the underlying mechanisms of apoptosis induced in hypoxic/ischemic condition and its treatment methods are unsettled. Cobalt chloride (CoCl_(2)) has been known to mimic hypoxic condition including the production of ROS. Epigallocatechin gallate (EGCG). a green tea polyphenol, has diverse pharmacologial activities in cell growth and death. This study was aimed to investigate the apoptotic mechanism by CoCl_(2) and effects of EGCG on CoCl_(2)-induced apoptosis in PC12 cells. Administration of CoCl_(2) decreased cell survival in dose- and time-dependent manners and induced genomic DNA fragmentation. Treatment with 100 µM EGCG for 30 min before PC12 cells were exposed to 150 µM CoCl_(2), being resulted in the cell viability and DNA fragmentation being rescued. CoCl_(2) caused morphologic changes such as cell swelling and condensed nuclei, whereas EGCG attenuated morphologic changes by CoCl_(2). EGCG suppressed the apoptotic peak and a loss of Δψ_(m) induced by CoCl_(2). CoCl_(2) decreased Bcl-2 expression but Bax expression was not changed in CoCl_(2)-treated cells. EGCG attenuated the Bcl-2 underexpression by CoCl_(2). CoCl_(2) augumented the cytochrome c release from mitochondria into cytoplasm and increased caspase-8, -9 and caspase-3 activity, a marker of the apoptotic executing stage. EGCG ameliorated the incruement in caspase-8, -9 and -3 activity, and cytochrome c release by CoCl_(2). NAC (N-acetyl-cysteine), a scavenger of ROS, attenuated CoCl_(2)-induced apoptosis in consistent with those of EGCG. These results suggest, that CoCl_(2) induces apoptotic cell death through both mitochondria- and death receptor-dependent pathway and EGCG has neuroprotective effects against CoCl_(2)-induced apoptosis in PC12 cells. 신경세포자멸사는 저산소 및 허혈환경에서 일어나며 이러한 세포죽은 reactive oxidant species (ROS) 생성을 동반함이 알려져있다. 그러나, 저산소 및 허혈환경에서 일어나는 세포자멸사의 기전 및 그 치료방법은 아직 정립되어 있지 않다. CoCl_(2)는 ROS를 생성하는 등 저산소환경과 유사한 조건을 초래하는 것으로 알려져 있다. Epigallocatechin gallate (EGCG)는 녹차의 polyphenol 성분으로서 세포성장과 죽음에 다양한 약리학적 효과를 나타냄이 알려져 있다. 본 연구는 PC12 세포에서 CoCl_(2)에 의한 세포자멸사기전을 밝히고 이에 미치는 EGCG의 효과를 조사하는데 목적이 있다. Cell viability는 MTT 측정으로 조사되었고, DNA fragmentation은 DNA laddering으로 조사되었다. Bcl-2와 Bax발현 정도는 RT-PCR로, caspase-3와 -9의 활성은 spectrophotometer, caspase-8의 활성은 flow cytometry에 의해 측정되었다. 미토콘드리아에서 세포질로 분비된 cytochrome c는 western blot으로, 분해된 DNA 양과 미토콘드리아 세포막전위 (Δψ_(m))는 FACScan으로 조사되었다. CoCl_(2)투여로 PC12 세포수는 용량 및 시간 의존형태로 감소하였고, genomic DNA fragmentation이 발생하였다. CoCl_(2)투여로 야기된 cell viability의 감소와 DNA fragmentation은 EGCG 전처치에 의해 억제되었다. CoCl_(2)은 세포용적팽창과 condensed nuclei 같은 형태적 변화를 일으켰으며, apoptotic peak, Δψ_(m)감소 및 cytochrome c 유리를 야기하였다. EGCG는 CoCl_(2)에 의한 세포형태변화, apoptotic peak, Δψ_(m)소실 및 cytochrome c 유리를 억제시켰다. CoCl_(2)는 Bcl-2 발현을 감소시켰지만, Bax 발현에는 영향을 미치지 않았다. EGCG는 CoCl_(2)에 의해 야기된 Bcl-2 발현 감소를 억제시켰다. CoCl_(2)는 caspase-3, -8, 그리고 -9의 활성을 증가시켰으며, EGCG는 CoCl_(2)에 의한 세포자멸사를 억제시켰다. 본 실험결과는 PC12 세포에서 CoCl_(2)가 미토콘드리아 의존 및 death receptor의존 기전으로 세포자멸사를 일으키며, EGCG는 세포자멸사기전을 억세지킴으로 신경보호기능을 가짐을 시사하였다.

지역사회 주민의 인비인후과 영역질환의 사회의학적 조사

최상규,남철현,김무룡,김기열,강영우,문기내 慶山大學校 保健福祉硏究所 2002 保健福祉硏究 Vol.7 No.-

This study was conducted to examine ear, nose, and throat diseases of community residents and related factors in Korea. 475 people who were experienced in suffering from the ear, nose, and throat diseases were chosen as the subjects of this study. Data were collected in Daegu, Kimchon, Andong, Pohang, Kyungsan from February 1, 2000 to May 30, 2000. The results of this study are summarized as follows. 1. Among ear, nose, and throat diseases, the incidence of throat diseases was highest (42.3%). The incidence rate of nose diseases was 31.9%, while that of ear diseases was 25.7%. The incidence of these diseases were significantly related to the variables of sex, age, occupation, religion, education level, smoking, and drinking. 2. When the respondents were afflicted with ear diseases, 47.7% of them was treated in ear, nose, and throat hospitals or clinics, while 29.4% of them was treated in general hospitals or clinics. 13.2% of them just endured without receiving treatment. 5.7% of them was treated in their homes and 3.9% of them was treated in pharmacies. 3. 28.9% of the respondents was treated for their ear diseases during two weeks; 24.2% 'during one week'; 20.5% 'during three to four days'; 12.6% 'during one to two days'; 9.0% 'during one to two days'; 4.8% 'during over six months'. The period of treatment was significantly related to the variables of sex, age, occupation, marital status, religion, smoking, drinking, and exercise. 4. When the respondents took nose diseases, 27.4% of them was treated in ear, nose, and throat hospitals or clinics, while 24.7% of them was treated in general hospitals or clinics. 18.6% of them just endured without receiving treatment. 17.7% of them was treated in pharmacies and 5.9% of them was treated in their homes. 5. 27.0% of the respondents was treated for their ear diseases during three and four days; 23.6% 'during on week'; 17.3% 'during two weeks'; 13.5% 'during one to two weeks'; 10.0% 'during one to two months'; 8.6% 'during over six months'. The period of treatment was significantly related to the variables of sex, ccupation, religion, education level, smoking, drinking, and exercise. 6. The throat diseases were caused by cold (30.2%), tonsils (29.3%), and bronchitis (15.7%). When the respondents took throat diseases, 26.1% of them was treated in ear, nose, and throat hospitals or clinics, while 25.3% of them was treated in general hospitals. 20.2% of them was treated in pharmacies and 12.4% of them just endured without receiving treatment. 10.3% of them received reatment in clinics, while 5.6% of them was treated in their homes. 7. The level of satisfaction with treatment for ear diseases was 3.58±1.12 points on the basis of 5 points, while that for throat diseases was 3.19±0.085 points. In case of information sources on ear, nose, and throat diseases, 31.8% of the respondents obtained the information from doctors, while 21.4% of them got it from TV or Radio. 15.9% of them obtained it from family members, neighbors, or friends and 10.0% of them obtained it from magazines, newspapers or pamphlet. Only 7.0% of them got it from pharmacists. 8. 67.2% of the respondents thought that mass media dealt with the ear, nose, and throat diseases lightly. 40.6% of them replied that education and publicity of those diseases would be necessary, while 10.7% of them replied those would not be necessary. Among the ear, nose, and throat diseases, the incidence rate of throat diseases was highest (42.3%). The ear diseases showed the highest level of satisfaction with treatment, while the throat diseases displayed the lowest level of satisfaction with treatment. Although the diseases are very serious in Korea, they are dealt with lightly in terms of education and publicity through using mass media. Therefore, the government, otorhinolaryngologists, and related associations must make great efforts to prevent the diseases.

신 손상 환자의 고식적 요법에 관한 임상적 고찰

김희철,전윤수,김민의,이남규,박영호 순천향의학연구소 1996 Journal of Soonchunhyang Medical Science Vol.2 No.2

Recently according to the increase of the traumatic patient there is a trent for the prevalence of renal injuries to increase. The key point in managing the renal injuries is that we should make decision the treatment plan after accurate diagnosis from clinical symptoms, physical examination, radiologic studies. The goal of the management is the conservation of the renal function. The management of renal injuries by nonoperative or operative methods has been a subject of controversy for more than 2 decades. A aggressive immediated operative approach is generally advocated in some centers, while a more watchful conservative approach is endorsed in others. From January 1985 to May 1995, 159 patients with renal injury had been managed at Soonchunhyang University Hospital. Among 159 patients, 83 patients were classified with minor renal injury and 76 patients major renal injury. The Computerized Tomography was useful in diagnosing stage of injuries and detecting combined injuries which were not detected in excretory urography. All stabilized patients were managed by careful continuous observation, bed rest, appropriate fluid resuscitation and prophylactic antibiotic coverage, but unstabilized patients(17 cases) were managed by immediate operation. Complications occurred in 10 patients with a major renal injury associated with a devascularized fragment but not in other patients. In conclusion, the accurate diagnosis and treatment plan of renal injury with computerized tomography are important to avoid improper treatment. I conclude that conservative management of minor renal injury and major renal injury associated with vascularized fragment is a proper method of treatment. However, early surgical intervention should be considered in patients with major renal injury associated with devascularized fragment because of high complication rate and delayed surgical intervention rate.