• Journal of Yeungnam Medical Science
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• 제19권1호
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• pp.55-62
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• 2002

Proinflammatory cytokine인 IL-1과 호중구는 급성폐손상의 발병기전엔 관여한다고 알려져있다. IL-1을 기도내로 주입시 호중구의 폐침윤이 일어나며, 활성화된 호중구에서 분비된 단백분해효소인 elastase는 급성폐손상을 일으킨다. 최근 elastase에 대한 억제제들이 몇 종류 개발되었는 데, 이들 합성 elastase 억제제들은 동물실험에서 폐의 염증성 손상을 감소시켰다고 보고되고 있다. 그 중 ICI 200,355는 human leukocyte elastase의 선택적이고 강력한 억제제로 보고되고 있어, 본 연구에서는 IL-1을 기도내로 주입하여 유발된 급성폐손상 흰쥐의 모텔에서 ICI 200,355를 투여했을 때 폐의 염증과 단백유출을 감소시켜 급성폐손상의 치료에 도움이 되는지 알아보고자 하였다. 실험대상은 흰쥐로 하였고, 이들을 무작위로 세 군으로 나누었다. 1군은 생리식염수를 기도내로 주입하고 생리식염수를 복강내로 투여하였고, 2 군은 IL-1을 기도내로 주입하고 생리식염수로 복강내로 투여하였으며, 3 군은 IL-1을 기도내로 주입하고 ICI 200,355를 복강내로 투여하였다. 5시간이 경과한 후 흰쥐에서 폐세척을 시행하여 회수된 세척액에서 호중구수, cytokine-induced neutrophil chemoattractant(CINC) 농도 그리고 단백량을 측정하였다. 그리고 개흉술로 얻은 폐조직에서 호중구의 침윤정도를 알아보기 위해서 폐조직내 myeloperoxidase(MPO) 활성도를 측정하였다. 한편 폐모세혈관의 단백유출의 정도를 측정하기 위해서 lung leak index를 구하였다. 그 결과로 IL-1을 기도내로 주입한 군은 폐세척액의 호중구수, CINC 농도 및 단백량치, 폐조직내 MPO 활성도 그리고 lung leak index 등 모든 측도에서 유의하게 증가되었다. 급성 폐손상모텔에 ICI 200,355를 복강내로 투여한 군에서 폐세척액의 호중구수 및 단백량치, 폐 조직내 MPO 활성도, lung leak index가 유의하게 감소되었으나 폐세척액의 CINC 농도는 감소되지 않았다. 결론적으로 IL-1의 기도내 주입으로 유발된 급성폐손상 모텔에서 neutrophil elastase 억제제인 ICI 200,355의 투여로 이미 증가된 CINC 농도에는 변화없이 폐의 염증과 단백유출을 감소시켜 급성폐손상을 억제시키는 것으로 생각된다.

• The Korean Journal of Physiology and Pharmacology
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• 제3권3호
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• pp.263-273
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• 1999

The role of phospholipase $A_2\;(PLA_2)$ in acute lung leak induced by intestinal ischemia was investigated in association with neutrophilic respiratory burst. To induce lung leak, we generated intestinal ischemia for 60 min prior to the 120 min reperfusion by clamping superior mesenteric artery in Sprague-Dawley rats. Acute lung leak was confirmed by the increased lung leak index and protein content in bronchoalveolar fluid. These changes were inhibited by mepacrine, the non-specific $PLA_2$ inhibitor. The lung myeloperoxidase (MPO) activity denoting the pulmonary recruitment of neutrophils was increased by intestinal I/R, but decreased by mepacrine. Simultaneously, the number of leukocytes in bronchoalveolar fluid was increased by intestinal ischemia/reperfusion (I/R) and decreased by mepacrine. Gamma glutamyl transferase activity, an index of oxidative stress in the lung, was increased after intestinal I/R but decreased by mepacrine, which implicates that $PLA_2$ increases oxidative stress caused by intestinal I/R. The $PLA_2$ activity was increased after intestinal I/R not only in the intestine but also in the lung. These changes were diminished by mepacrine. In the cytochemical electron microscopy to detect hydrogen peroxide, intestinal I/R increased the generation of the hydrogen peroxide in the lung as well as in the intestine. Expression of interleukin-1 (IL-1) in the lung was investigated through RT-PCR. The expression of IL-1 after intestinal I/R was enhanced, and again, the inhibition of $PLA_2$ suppressed the expression of IL-1 in the lung. Taken together, intestinal I/R seems to induce acute lung leak through the activation of $PLA_2$, the increase of IL-1 expression associated with increased oxidative stress by neutrophilic respiratory burst.

• 지구물리와물리탐사
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• 제25권3호
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• pp.120-128
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• 2022

국내에는 17,000여개의 저수지가 존재하며, 이중 85% 이상은 50년 이상 경과된 노후 저수지이다. 이들 저수지는 내부침식 및 세굴 현상에 의한 누수와, 그에 따른 붕괴의 위험에 직면하고 있다. 이들 저수지 및 댐의 붕괴를 방지하기 위해서는 누수를 조기에 파악하고 대비하는 것이 중요하다. 전기비저항 탐사는 저수지의 전반적인 상태 파악은 물론 누수의 발달여부 탐지가 가능한 비파괴, 실시간, 현장조사법이다. 이러한 장점 때문에 전기비저항 탐사법은 저수지 안전진단에 널리 사용되고 있다. 그러나 전기비저항 탐사법은 저수지의 안전도에 대한 정량적인 지수를 제공하지 못해 공식적으로 저수지 정밀 안전진단의 상태평가 항목에 포함되어 있지 못하다. 이 연구에서는 전기비저항 탐사와 유도분극 탐사를 통하여 계산된 수분함량에 근거한 정량적 누수지수 산출법을 제시하였다. 특히 일회성 탐사와 모니터링에 의한 정량적 누수지수 산출법을 개발하여 전기비저항 탐사와 유도분극 탐사가 향후 저수지 정밀 안전진단의 상태평가 항목으로 진입할 수 있는 이론적 기반을 제시하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제1권1호
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• pp.71-78
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• 1997

In an attempt to investigate the role of phospholipase $A_2$($PLA_2$) in interleukin-l (IL-l) induced acute lung injury, mepacrine was tried to inhibit $PLA_2$ in IL-l induced ARDS rats. For confirmation of acute lung injury by IL-l, and to know the role of neutrophils in this injury, lung leak index, lung myeloperoxidase(MPO), number of neutrophils and protein content in the bronchoalveolar lavage (BAL) and wet lung weight were measured. At the same time lung $PLA_2$ was measured to know the effect of IL-l on $PLA_2$ activity. Pulmonary surfactant was also measured for an investigation of type II alveolar cell function. Neutrophil adhesion assay was performed to know the effect of $PLA_2$ inhibition in vitro with human umbilical vein endothelial cells (HUVEC). For precise location of injury by IL-l, morpholgical study was performed by electron microscopy. Five hours after instillation of IL-l (50 ng/rat), lung leak index, protein content, number of neutrophils, lung MPO and wet lung weight were increased significantly. Five hours after IL-l instillation lung $PLA_2$ activity was increased significantly, and increased surfactant release was observed in IL-l induced ARDS rats' BAL. In contrast, in rats given mepacrine and IL-l, there was decrease of acute lung injury i.e. decrease of lung leak index, wet lung weight, protein content, number of neutrophils in BAL and decreased lung MPO activity. Mepacrine decreased surfactant release also. Interestingly, inhibition of $PLA_2$ decreased adhesion of human neutrophils to HUVEC in vitro. Morphologically, IL-l caused diffuse necrosis of endothelial cells, type I and II epithelial cells and increased the infiltration of neutrophils in the interstitium of the lung but after mepacrine treatment these pathological findings were lessened. On the basis of these experimental results it is suggested that $PLA_2$ has a major role in the pathogenesis of acute lung injury mediated by neutrophil dependent manner in IL-l induced acute lung injury.

• 대한기계학회논문집B
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• 제34권2호
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• pp.137-143
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• 2010

발전기 고정자 권선 내부의 완전 건조는 누수시험을 위한 필요/충분조건이다. 발전기 운전에 의한 고주기 피로는 미세 균열 발생의 원인이 되고, 미세 균열에서의 물분자는 누설 진단의 신뢰성을 저하시킨다. 이와같은 이유로, 발전기 고정자 권선에 대한 누수시험에서 권선에 누설처가 있음에도 불구하고 누설이 없다는 결론과 같은 오류를 범하고 있다. 발전기 제작사는 누수시험을 고유한 건조 판정 기준을 제시하고 있지만, 실제로는 어떤 판정 기준도 누수시험을 위해 정확하게 건조 판정 기준을 지시하고 있지는 못하고 있는 실정이다. 그 이유는 발전기 고정자 권선의 복잡한 구조와 효과적인 건조 장비의 부재 때문이다. 본 논문에서는 수 냉각 발전기 고정자 권선의 내부 건조 여부를 판정하기 위한 건조 판정 기준을 완벽하게 제안하였으며 실험적으로 증명하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제2권4호
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• pp.479-491
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• 1998

In order to know the pathogenesis of adult respiratory distress syndrome (ARDS) in association with the oxidative stress by neutrophils, the role of platelet activating factor (1-0-alkyl-2-acetyl-snglycero-3-phosphocholine, PAF) was investigated during acute lung injury induced by interleukin- $1{\alpha}$ (IL-1) in rats. An insufflation of IL-1 into the rat's trachea increased the acetyltransferase activity in the lung and the increase of PAF content was followed. As evidences of acute lung injury by neutrophilic respiratory burst, lung leak index, myeloperoxidase activity, numbers of neutrophils in the bronchoalveolar lavage fluid, neutrophilic adhesions to endothelial cells and NBT positive neutrophils were increased after IL-1 treatment. In addition, a direct instillation of PAF into the trachea caused acute lung leak and the experimental results showed a similar pattern in comparison with IL-1 induced acute lung injury. For the confirmation of oxidative stress during acute lung leak by IL-1 and PAF, a histochemical electron microscopy was performed. In IL-1 and PAF treated lungs of rats, the deposits of cerrous perhydroxide were found. To elucidate the role of PAF, an intravenous injection of PAF receptor antagonist, WEB 2086 was given immediately after IL-1 or PAF treatment. WEB 2086 decreased the production of hydrogen peroxide and the acute lung leak. In ultrastructural study, WEB 2086 mitigated the pathological changes induced by IL-1 or PAF. The nuclear factor kappa B (NFkB) was activated by PAF and this activation was inhibited by WEB 2086 almost completely. Based on these experimental results, it is suggested that the PAF produced in response to IL-1 through the remodeling pathway has the major role for acute lung injury by neutrophilic respiratory burst. In an additional experiment, we can also come to conclude that the activation of the NFkB by PAF is thought to be the fundamental mechanism to initiate the oxidative stress by neutrophils causing release of proinflammatory cytokines and activation of phospholipase $A_2$.

• 국제강구조저널
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• 제18권5호
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• pp.1710-1722
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• 2018

Investigating remained damages from terrible earthquakes, it could be concluded that some events including explosion because of defect and failure in the building mechanical facilities or caused by gas leak, firing, aftershocks, etc., which are occurred during or a few time after the earthquake, will increase the effects of damages. In this paper, by introducing a complete risk analysis which included direct and indirect risks for earthquake (the main shock) and aftershock, the corresponding robustness index was created that called as "robustness index sequential critical events risk-based". One of the main properties of the intended robustness index is using progressive collapse percentage in its evaluation. Then, in a numerical example for a 4-storey moment resisting steel frame structure, a method is presented for obtaining all effective parameters in robustness index evaluation based on the intended risk and at last its results were reported.

• Ocean Systems Engineering
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• 제8권1호
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• pp.41-55
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• 2018

Accidental oil and gas leak is a critical concern for the offshore industry because it can lead to severe consequences and as a result, it is imperative to evaluate the probabilities of occurrence of the consequences of the leakage in order to assess the risk. Event Tree Analysis (ETA) is a technique to identify the consequences that can result from the occurrence of a hazardous event. The probability of occurrence of the consequences is evaluated by the ETA, based on the failure probabilities of the sequential events. Conventional ETA deals with events with crisp failure probabilities. In offshore applications, it is often difficult to arrive at a single probability measure due to lack of data or imprecision in data. In such a scenario, fuzzy set theory can be applied to handle imprecision and data uncertainty. This paper presents fuzzy ETA (FETA) methodology to compute the probability of the outcomes initiated due to oil/gas leak in an actual offshore-onshore installation. Post FETA, sensitivity analysis by Fuzzy Weighted Index (FWI) method is performed to find the event that has the maximum contribution to the severe sequences. It is found that events of 'ignition', spreading of fire to 'equipment' and 'other areas' are the highest contributors to the severe consequences, followed by failure of 'leak detection' and 'fire detection' and 'fire water not being effective'. It is also found that the frequency of severe consequences that are catastrophic in nature obtained by ETA is one order less than that obtained by FETA, thereby implying that in ETA, the uncertainty does not propagate through the event tree. The ranking of severe sequences based on their probability, however, are identical in both ETA and FETA.

• 설비공학논문집
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• 제19권7호
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• pp.537-544
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• 2007

To facilitate comparative analysis on the effects of numerous parameters concerning design and operation of a desiccant rotor, it is firstly required to represent the dehumidification performance as numerical indices. In this work is proposed two performance indices of a desiccant rotor: the humidity effectiveness and the enthalpy-leak ratio. The humidity effectiveness represents the actual dehumidification as compared with the dehumidification in an ideal case, while the enthalpy-leak ratio represents the enthalpy transfer from the regeneration side to the dehumidification side. In an ideal case, the two indices approach one and zero, respectively. The effects of numerous parameters on the dehumidification performance of a desiccant rotor are investigated through numerical simulation and represented with the two indices. The results show that the performance indices are mainly determined by three nondimensional parameters each representing the thermal capacity, the sorption capacity, and the transfer capacity of a desiccant rotor.

• Tuberculosis and Respiratory Diseases
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• 제44권6호
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• pp.1343-1352
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• 1997

연구배경 : 패혈증이나 이에 합병된 급성호흡곤란증후군 환자들은 고열을 동반하는 경우가 많다. 발열은 조직의 대사를 항진시키므로 조직내 산소공급에 제한이 초래되는 패혈증 환자들에서 발열이 동반되는 경우 열을 동반하지 않는 경우보다 중요기관의 산소공급이 상대적으로 저하될 가능성이 있다. 반면, 발열상태는 조직내 열충격단백질 (heat shock protein, HSP)의 생성을 유도하여 패혈증에 의한 비가역적인 손상으로부터 세포들을 보호함으로써 생체의 방어기전에 유려하게 작용할 수도 있어 패혈중 이에 합병된 급성 폐손상 환자들의 발열에 대한 임상적 의미는 아직 규명되어 있지않았다. 본 연구는 열을 전처치 하였거나 하지 않은 Sprague-Dawley rat의 기도에 TNF를 주입한 후 TNF에 의해 유도되는 급성 폐손상의 정도를 비교함으로써 열이 급성 폐손상에 미치는 효과를 관찰하고자 하였다. 대상 및 방법 : 급성 폐손상의 지표로는 백서의 우측폐내 $I^{125}$의 분당 측정량 대비 1mL의 혈중내 $I^{125}$의 분당 측정량의 비율로 정의한 단백누출지표와 백혈구의 조직내 침윤정도를 반영하는 myeloperoxidase(MPO)의 활성도를 측정하였다. 결과는 평균(${\pm}$ 표준오차)로 표기하였다. 결 과 : 백서의 기도에 생리식염수를 주입한 백서들은 열을 전처치 하였거나 하지 않은 경우 두 군사이의 단백 누출 지표는 각각 0.099(${\pm}0.024$) 및 0.123(${\pm}0.005$)로서 차이가 없었으며 MPO도 4.58(${\pm}0.79\;U/gm$) 및 7.32(${\pm}0.97\;U/gm$)로서 열을 전처치 할 경우 다소 감소되는 경향(P=0.064)를 보였으나 차이가 없었다. 백서의 기도에 TNF-$\alpha$을 주입한 치료군에서 열 전처치한 백서군은 단백누출지표 0.137(${\pm}0.012$) 및 MPO 7.01(${\pm}0.89\;U/gm$)로서 열 전처치 않은 백서군 단백누출지표 0.186(${\pm}0.015$) 및 MPO 14.11(${\pm}1.08\;U/gm$)에 비해 낮았으며(각 P<0.05) 정상군과는 차이가 없었다. MPO 활성도가 단백 증가되었다(r=0.564, P<0.005). 열 전처치 하지 않은 백서에 비해 열 전처치한 백서의 폐 조직내 HSP 72 단백질의 발현은 열 충격 후 18시간 및 23시간 뒤에도 증가되어 나타났다. 결 론 : 백서에 열을 전처치 할 경우 TNF-$\alpha$로 유도되는 급성 폐손상이 경감되므로 발열이 백서의 방어기전에 유리하게 작용한 것으로 사료되었다.