• Tuberculosis and Respiratory Diseases
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• v.44 no.1
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• pp.104-113
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• 1997

Background : Toxic oxygen free radicals have been implicated as important pathologic mediators in many clinical disorders. Enhancing the intracellular content of antioxidant enzymes(superoxide dismutase, glutathione peroxidase, and catalase) can provide means of limiting biological damage caused by oxygen free radicals. The oxygen free radicals and changes of antioxidant enzymes are though to play a role in the pathogenesis of chronic obstructive pulmonary disease. Method : To investigate the pulmonary oxygen radical injury and the protective role of antioxidant enzymes in Chronic obstructive pulmonary disease(COPD), author measured the amount of thiobarbituric acid reactants, the activities of antioxidant enzymes and the sulfhydry1 groups of glutathione in serum and red blood cells from the patients with COPD(COPD patients) and the normal controls. Results : The thiobarbituric acid reactant in serum and red blood cells of COPD patients was increased than those of the normal controls, and the superoxide dismutase activity in red blood cells was no statistical difference in both groups. But the glutathione peroxidase and catalase activities in red blood cel1s of COPD patients were significantly lowered than those of the normal controls. The sulfhydry1 groups in serum and red blood cells were no statistically difference in both groups. Conclusion : These results suggest that the increased thiobarbituric acid reactants in serum and RBCs of chronic obstructive pulmonary disease mean oxygen radical toxicity, and the decreased glutathione peroxidase and catalase activities in RBC could take pan in pathogenesis of chronic obstructive pulmonary disease.

• Tuberculosis and Respiratory Diseases
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• v.57 no.1
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• pp.72-77
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• 2004

Background : A tracheobronchial obstruction in lung cancer is associated with significant morbidity and mortality due to dyspnea, cough, hemoptysis, and recurrent respiratory infection. It is well known that one of standard treatments is photodynamic therapy (PDT) in tracheobronchial obstruction after radiotherapy, chemotherapy, and/or surgery. We reported here the role of PDT in airway obstruction in patients advanced lung cancer. Method : Pre-treatment protocol consisted of clinical, radiologic, and bronchoscopic examination, pulmonary function test, and assessment of Karnofsky performance status. A 2 mg/kg of porfimer sodium was injected intravenously, and then followed by cylindrical and/or interstitial irradiation with 630 nm of laser after 48 hours. The repeated bronchoscopy for debridement of necrotic tissue and re-illumination was performed after 48 hours. Result : Improved airway obstruction and selective tumor necrosis were achieved by photodynamic therapy in all cases. Dyspnea and performance status were improved in three cases. A purulent sputum, fever and hemoptysis were improved in one of five cases. After PDT, all patients showed temporarily aggravation of dyspnea, two of five showed febrile reaction for a few days and nobody presented photosensitivity reaction, hemoptysis and respiratory failure. Conclusion : Our experiences of PDT are effective in palliation of inoperable advanced lung cancer in terms of tracheobronchial obstruction.

• Journal of Chest Surgery
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• v.35 no.7
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• pp.542-547
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• 2002

Background: Postpneumonectomy empyema(PPE) is an infrequent but potentially life-threatening complication. To date, various surgical efforts have been made to manage this complication. We reviewed our 20-year surgical experience of PPE and long-term follow-up data. Material and Method: Total of 37 patients who were treated for PPE between fan, 1980 and Jun, 2000 were included. Various clinical factors such as micro-organism, operative method and timing, presence of bronchopleural fistula(BPF), underlying disease and fate of empyema cavity were retrospectively reviewed and analyzed. Result: Majority of patients(34) underwent Eloesser operation for effective drainage. There was only one operative mortality. The causative organisms were Staphylococcus species and Pseudomonas species in 46% BPF was found in 20 cases, among which spontaneous closures took place in 4 cases. The chest wall was closed in 40%(8/20) of patients with BPF, compared to 59%(10/17) without BPF. The closure rate was statistically better in patients without BPF(p=0.006). Even though the patients with benign disease showed higher closure rate(50%) than those with lung cancer (31%), the difference was not significant(p=0.25). Conclusion: Eloesser procedure was an effective method for initial drainage of PPE cavity with low operative mortality. Given the findings of low spontaneous closure rate of BPF, aggressive approach to close the BPF is mandatory to achieve the final goal of chest wall closure. It was found that majority of patients still left their chest cavity opened, even after controlling the active inflammation of the empyema cavity. More aggnessive approach for chest wall closure is recommended in all patents with benign disease and in selective patients with lung cancer if there is no evidence of recurrence at several years after the initial operation.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.12
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• pp.68-74
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• 2010

A sub-${\mu}$W CMOS Wien-Bridge oscillator for ultra low power (ULP) radio applications is presented. The Wien-Bridge oscillator is based on an non-inverting opamp amplifier with a closed-loop gain $1+R_2/R_1$ as a means of providing necessary loop gain. An additional RC network provides appropriate phase shift for satisfying the Barkhausen oscillation condition at the given frequency of 1/($2{\pi}RC$). In this design, we propose a novel loop gain control method based on a variable capacitor network instead of a rather conventional variable resistor network. Implemented in $0.18{\mu}m$ CMOS, the oscillator consumes only 560 nA at the oscillation frequency of 22 kHz.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.12-16
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• 2010

본 연구에서는 건설현장의 특별 피난계단 출입문 크기와 구조의 다양성을 고려한 자동폐쇄장치의 설계방안을 제시하였다. 이를 위해서 급기가압실의 방연풍속, 누설량 그리고 송풍기의 용량이 일정한 경우 출입문이 폐쇄되기 위한 힘의 상관관계를 회전각도와 회전속도의 변화에 따라서 분석하였으며, 방화문의 폭이 1,100 mm, 1,300 mm 인 경우 각각에 대해서 개방력과 폐쇄력을 측정하였다. 그 결과 현장 조건을 만족할 수 있는 자동폐쇄장치에 의한 방화문의 폐쇄조건 및 회전각도와 회전속도의 변화를 고려한 개방력과 폐쇄력의 최적 설계범위가 존재함을 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.461-464
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• 2020

지상파 방송에서는 청각장애인을 위해 폐쇄자막(closed caption) 서비스가 제공되고 있다. 현재의 폐쇄자막 방송은 속기사가 실시간으로 방송을 보면서 입력하기 때문에 지연이 있다. 또한 이렇게 입력된 폐쇄자막은 TV 프로그램 영상과 별도로 저장되기 때문에 영상과 그 시작점이 맞지 않는 경우가 대부분이다. 폐쇄자막을 온라인 서비스 등에 제공하고자 할 때 이러한 문제로 인해 영상과의 동기가 맞지 않아 사용이 어렵다. 본 논문에서는 TV 프로그램의 음성을 인식하여 동기화된 텍스트를 추출하고, 이를 기 저장된 폐쇄자막과 정렬하여 동기화하는 방법을 제안한다. 실제 TV 프로그램과 자막에 적용하였을 때 대부분의 음절과 라인에서 동기화가 정확히 이루어짐을 확인하였다.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.63-69
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• 1990

To study the follicular atretic mechanism in mammalian ovary, the medium-sized (3.0-6.0mm) follicles of porcine ovary were morphologically classified as nonnal and atretic. Steroid concentrations in the follicular fluid were analyzed by radioimmunoassay, and the proteins in that fluid were electrophoretically separated. Concentrations of progesterone in the atretic follicular fluid of follicular phases were higher than those of normal ones (p < 0.05). Concentrations of testosterone were high in normal luteal and atretic follicular-phases follicles. The concentrations of estradiol remained significanily lower in atretic follicular-phases follicles than normal. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis of follicular fluid proteins, four kinds of proteins (20K, 32K, 33K, 38K) were detected, and those proteins were not present in sera. According to the ovarian cycle, proteins of MW of 112K and 141K were identified. In atretic follicular fludies, MW of 23K and 24K were specifically detected. From the above results, we can conclude that, as ovarian cycle changes, steroid contents and protein composition in atretic follicular fluid are different from the normal developing follicular fluid. To further understand the physiologic roles of the proteins present in the atretic follicular fluids, these proteins need to be characterized and identified.

• Clinical and Experimental Pediatrics
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• v.48 no.11
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• pp.1212-1218
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• 2005

Purpose : Forward pulmonary blood flow may be absent in some neonates with Ebstein's anomaly by anatomical or functional pulmonary atresia in association with the elevated pulmonary vascular resistance, patent ductus arteriosus and tricuspid regurgitation. We reviewed the presentation and outcomes of symptomatic neonates with Ebstein's anomaly focusing on the pulmonary atresia. Methods : Clinical presentation and outcome of 15 symptomatic neonates with Ebstein's anomaly seen at Asan medical center from 1998 to 2004 were reviewed. Results : Ten(67%) of 15 patients showed no forward pulmonary blood flow and 6 of them had functional pulmonary atresia. $O_2$ saturation and pH were lower and cardiothoracic(CT) ratio in chest radiography was more increased in the patients with pulmonary atresia than in the patients without pulmonary atresia(P<0.05). pH and CT ratio were not different between the anatomical and functional pulmonary atresia group, but $O_2$ saturation was lower in functional atresia group(P<0.05). 13 patients(87%) were managed with $PGE_1$. 4 of 6 patients with functional pulmonary atresia were treated with inhaled nitric oxide. Surgery was performed in 1 of 5 patients without pulmonary atresia and in 8 of 10 patients with pulmonary atresia during follow-up period(mean 37 months). 3 patients(20%) died and none of patients without pulmonary atresia died. Conclusion : We found that most symptomatic neonates with Ebstein's anomaly had functional or anatomical pulmonary atresia. The neonates with Ebstein's anomaly who had no forward pulmonary blood flow were more symptomatic and needed surgery earlier. Further studies will be needed to distinguish effectively functional and anatomical pulmonary atresia and to manage appropriately neonates with functional atresia.

• Solar Energy
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• v.7 no.1
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• pp.42-52
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• 1987

파형 단면을 가진 유하식 집열기의 이론 및 실험 결과로서 유량, 각도등 집열성능에 미치는 영향등이 고려되었다. 입구 온도와 출구온도 차이가 적을 경우에는 이론과 실험치가 잘 맞으나 온도차이가 많을 경우 혹은 입구온도가 높을 때에는 투과체안에 생기는 결로 및 수증기의 영향으로 편차가 커진다. 개방회로와 폐쇄회로의 경우를 구분하여 실험되었는데 개방회로의 경우 효율은 약간 저하되지만 전반적인 성능은 폐쇄회로와 같은 경향을 나타내었다. 개방회로는 과열을 막는 방편으로 이용될 수 있다.

• 건강소식
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• v.36 no.12
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• pp.22-24
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• 2012

한국인의 사망 원인 1위는 단연 암이다. 간혹 자살이 그 순위를 넘보기는 하지만. 그런데 최근 몇 년 새 이를 맹추격하는 강적이 나타났다. 그 이름도 생소한 만성 폐쇄성 폐질환. 이름 그대로 오랜 기간 폐를 못살게 구는 병으로 담배가 가장 큰 주범이다. 노년기가 무한대로 늘어난 고령화 시대, 팔팔한 40대부터 병상을 차지하고 싶지 않다면 지금부터 시작해야 한다, 진실한 금연 생활을!