허혈 조건부여가 심근기능의 회복에 미치는 영향 : 적출 심장모델을 이용한 실험연구 Isolated heart experimental study

백광제,김준식,한승백,전영진,이인성 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Background: Brief episode of coronary artery occlusion(i.e.,ischemic preconditioning) makes the heart more resistant to injury from a subsequent ischemic insult. Although a great deal of effort has been made in studying ischemic preconditioning, the underlying mechanism of ischemic preconditioning and its effect on hypothermic insult has not been elucidated. This study was performed to see whether ischemic preconditioning protects against the depression of cardiac contractility induced by hypothermic cardioplegic arrest/reperfusion. And recently, adenosine was known to have some correlation with the mechanism of preconditioning. If so, does this effect remain after the blockade of adenosine receptor by 8-phenyl theophyline? Method: Twenty-four Sprague-Dawley rat weighed 250-350g were used and divided into three groups. Rat hearts were removed rapidly, and each isolated heart paced with a rate of 180/min was perfused by modified Krebs-Hensleit buffer(KHB) solution on a Langendorff apparatus for an hour. After obtaining baseline data including left ventricular pressure(LVP), dp/dt, and coronary flow, cardiac arrest was induced by perfusion of 0℃ crystalloid cardioplegic(St Thomas) solution. After that, all hearts were stored in the same St Thomas solution at same temperature for 2 hours. In group Ⅰ(control group), the heart was reperfused by KHB solution. In group Ⅱ(preconditioning group), the heart was subjected to two 2-minute episode of global ischemia followed by 5 minute reperfusion with KHB solution(preconditioning) before cardiac arrest. In group Ⅲ(phenyl theophylline group), the heart was subjected to preconditioning procedure and 8-phenyl theophylline at 10μM in concentration was added to KHB solution at time of reperfusion. Observing parameter was obtained in each group at 10, 20, 40 and 60 minutes after starting reperfusion and compared statistically by use of one way ANOVA test(STASTICA, release 4.5). p-value less than 0.05 was considered significant. Results: Although depressed LVP, dp/dt, and coronary flow were seen in all groups during the reperfusion period, the preconditioned group showed more effective recovery of LVP than that of the control group, especially at 10, 20 and 40 minutes(p<.05). We failed to demonstrate the difference between the phenyl theophylline group and the control group(p=NS). Conclusion: These results suggest that ischemic preconditioning has protective effect on recovery state of hypothemic cardioplegic arrest/reperfusion. Its protective effect was limited during early reperfusion stage and was blocked by adenosine blocker.

한국문제(Korean question)의 역사적 재구성과 6자회담 : 한반도협조체제의 전망 Prospect of the concert of the Korean Peninsula

백준기 한국외국어대학교 외국학종합연구센터 1997 국제지역연구 Vol.7 No.4

6자회담을 단순히 북핵문제를 해결하기위한 한시적이고 제한적인 논의구조로 상정하기 보다는 북핵문제가 배태한 역사적 조건과 극제환경을 고려하여 궁극적으로 한반도 문제의 안정적이고 항구적인 해결 가능성을 모색하는 제도적 틀로서 위치지우는 것이 필요하며 이를 위해 6자회담이 국제레짐(international regime)화 할 수 있는 가능성에 대해 이론적인 탐색이 중요하다. 냉전이 해체되면서 변화하고 있는 동아시아의 국제환경은 다자간 협력에 대한 가능성을 보여주고 있다. 높은 수준의 안보공동체나 국제기구의 결성은 현 단계에서 어려울 지라도 낮은 수준의 국제레짐의 모색이 현실적이다. 6자회담을 다자간 협력의 제도로 전환시키는 문제는 당분간 이러한 범위 내에서 가능하며 이것은 '헙조체제'(concertacion)'라는 형태가 하나의 대안이 될 수 있을 것이다. 북핵문제를 넘어서 6자회담을 '한반도 협조체제'로 전환시켜야한다. 이것은 더 높은 단계의 '제도로의 이행(the move to institutions)'의 시작이기도하다. It is necessary that we should bring up for discussion the six-party talks while considering the historic condition and international circumstances of what North Korean nuclear issues conceive rather than a temporary and limited discussion of the North Korea nuclear issue. Therefore, ultimately it is important to position the six-party talks as an institutional framework which searches for a stable and perpetual solution for korean issues and to do this a theoretical investigation on the possibility of making the six-party talks international regime must be done. The ending of the cold war has changed the international circumstances of East Asia where there is now the possibility of multilateral cooperation. Even if the formation of high-level security associations or international organizations. looks tough at the very moment a low standard international regime would be ideal. The issue of transferring the six-party talks into a multilateral institution system would be realistic within this range for the time being and this could be an alternative of it being 'Concertacion'. Henry Kisinger supposed it was international discussions on significant matters that made 19th century multi-polarized European countries in competition to relatively successfully evade war. The maintenance of European peace of European peace for a century has been assessed to be due to the so called contribution of the Concert of Europe. If we can find an encouraging model in Europe for the possibility of transferring the six-party talks into the Concert of the Korean Peninsula, there must be a shared awareness that the issues covering the threat of the terrorist in 'post-Post cold War period' and the proliferation of weapons of mass destruction are put ahead of diplomatic danger or uncertainty among participant countries. Together with this, the recognition of the threat posed of the issue where a particular country is emerging as a supreme power in a particular region(East Asia), has become a more significant standard than the difference of regimes, values and social patterns of 'whether or not it is socialism or capitalism'. The south and North Korean case, for example, is a more desperate issue. The six-party talks has begun for the purpose of solving the North's Nuclear Issue. However, the fundamental solution of the North Korean unclear issue is eventually related to the key to solve the Korean Question. Therefore, the agenda dealing with the North Korean nuclear issue should be ultimately expanded into the solution of the Korean question where there is reason why the six-party talks should be converted into the systemization of multilateral cooperation, and 'the Concert of the Korean Peninsular'. In the course of solving the North Korean unclear issue and the Korean question, the so-called democratic enlargement policy such as 'regime change'- whether or not its purpose is 'terrorism uprooting' or 'the principle of universal humanitarianism'-is unrealistic. No country is qualified to decide on another country's political culture and regime. This cannot be justified by the historical fact thar a country has had a long-term occupying period of another country. Any diplomatic policy carried out resorting to this urging, as Paul Kennedy said, can be defined as 'imperial overstretching'. Instead, we should start with persuasion and consultation' among participants. The six-party talks has begun with the solution of the North Korean nuclear issue, which was had a limited agenda in terms of time and space. However, it is obviously an historic event that has a particular destiny to cover the issue beyond the North Korean nuclear issue. This is an element related to the historical discourse regarding the Korean(Peninsular) question and the East Asia Peace issue. The Korean question is destined to walk a read onto globalization since it historically emerged. Since the time when the Korean Peninsular entered into the period of being a colony, the Korean question has become an international issue through serial political talks and is decided on or deferred by the deputy of so-called 'related countries' according to their interest. The six-party talks would not be an end but a new beginning. Under the circumstance where the surrounding greater power is returning to the history, we feel the necessity of converting the six-party talks into 'the Concert of the Korean Peninsula' beyond the North Korean nuclear issue. This would be the beginning of a move to the more enhanced institution.

분기배관(소화설비)의 등가길이에 따른 손실계수에 관한 연구

백열선 ; 백창선 ; 남준석 김천대학교 2007 김천대학교 논문집 Vol.28 No.-

This study is performed for calculation of loss coefficient complied with equiva-lent length for TBP(T-Branched Pipe). Pressure loss is tested by KFI Standard of TBP. Using the results, we known the two facts. First, equivalent length and loss coefficient is very similar at 4.5 m/s. Second, loss coefficient where the branched pipe will become larger at the run pipe comes to be few.

혼합유화제 비율에 따른 인계난연제 캡슐의 제조 및 특성 연구

백경현,이준영,홍상현,김중현 한국공업화학회 2004 응용화학 Vol.8 No.1

The microcapsules containing triphenyl phosphate (TPP) flame retardant have been prepared by using the epoxy resin (Novolac Type) with good physical properties and network structure. The reactants including TPP, epoxy resin and mixed surfactants were emulsified to oil in water (O/W) by the phase inversion technology and then conducted on the crosslinking of epoxy resin by In-situ polymerization. The capsule size and size distribution of TPP microcapsules was controlled by mixed surfactant ratio. The thermal property of TPP capsules were measured by the TGA. The morphology and capsule size were also investigated by the SEM respectively. TPP capsules with 1 : 1 of mixed surfactant (F127 : SDBS) ratio were more spherical and uniform than it with others. The TPP capsule size was 12~17㎛ and TGA results shows that TPP capsule efficiency was about 73%.

EFG와 IGF-I의 첨가배양이 돼지 미성숙 난포란의 체외성숙과 배발달에 미치는 영향

백준종,한만희,박병권,서길응,이규승 충남대학교 농업과학연구소 2007 농업과학연구 Vol.34 No.1

The present study was carried out to examine the effect of EGF and IGF-I in vitro maturation (IVM) of porcine oocytes and development of porcine IVM/IVF embryos. The results were summarized as follows : 1. The rates of nuclear maturation, penetrated oocytes, pronuclear formation, polyspermic oocytes and mean numbers of the penetrated sperm were not different in NCSU-23 maturation medium with 0, 1. 5 and 10 ng/ml EGF and IGF-I (P>0.05). 2. The rates of blastocyst formation at day 7 after in vitro fertilization in 0, 1, 5 and 10 ng/ml EGF groups were 11.2±1.5%, 15.0±8.3%, 16.8±2.8% and 21.4±2.0%, also 0, 1, 5 and 10 ng/ml IGF- I groups were 11.2±1.5%, 15.0±8.3%. 16.8±2.8% and 21.4±2.0%, respectively. In the total cells case, EGF groups were 22.8±3.7, 25.7±5.5, 26.0±4.2 and 35.1±4.7, also IGF-I groups were 21.5±3.7, 25.2±2.8, 26.2±2.9 and 33.2±3.6, respectively. Both 10 ng/ml EGF group and 10 ng/ml IGF-I group were significantly higher than those of other treatment groups (P<0.05). 3. The rates of blastocyst formation at day 7 in the NCSU23 culture medium of porcine IVF-produced embryos with 0, 1, 5, and 10 ng/ml EGF groups were 14.0±1.7%, 16.2±1.4%, 16.9±1.2% and 23.1±1.6%, also 0, 1, 5, 10 ng/ml IGF-I groups were 13.6±1.7, 15.7±4.5. 16.0±0.2 and 25.0±0.8, respectively. And in the total cells case, EGF grups were 21.8±2.9, 25.2+2.8, 39.7±2.7 and 46.2±3.6, also IGF-I groups were 20.7±2.9, 26.2±2.9, 24.6±2.4 and 46.1±3.5, respectively. Both 10 ng/ml EGF group and 10 ng/ml IGF-I group were significantly higher than those of any other treatment groups (P<0.05). In conclusion, these results suggested that the addition of 10 ng/ml EGF and IGF-I were effective on the blastocyst formation and total cells of blastocysts.

적응형 의사결정 트리와 최단 경로법을 이용한 기계 진단 및 보전 정책 수립

백준걸 한국경영과학회 2002 韓國經營科學會誌 Vol.27 No.2

CBM (Condition-Based Maintenance) has increasingly drawn attention in industry because of its many benefits. CBM problem is characterized as a state-dependent scheduling model that demands simultaneous maintenance actions, each for an attribute that influences on machine condition. This problem is very hard to solve within conventional Marlov decision process framework. In this paper, we present an intelligent machine maintenance scheduler, for which a new incremental decision tree learning method as evolutionary system identification model and shortest path problem as schedule generation model are developed. Although our approach does not guarantee an optimal scheduling policy in mathematical viewpoint, we verified through simulation based experiment that the intelligent scheduler is capable of providing good scheduling policy that can be used in practice.

성인성 호흡부전증(ARDS)의 호흡역학 개선을 위한 실험연구

백광제,김준식 大韓應急醫學會 1997 대한응급의학회지 Vol.8 No.1

The acute respiratory distress syndrome (ARDS) is a disorder of diffuse lung injury secondary to a wide variety of clinical insults including sepsis. It is manifested by impaired oxygenation, pulmonary edema, decreased static and dynamic compliance of lung, and increased airway resistance. Reduced lung compliance together with increased airway resistance is a hallmark of the syndrome and has generally been considered as the primary abnormality of lung mechanics. The study was designed to reproduce an ARDS condition in an animal model with acute lung injury and to determine whether these changes are reversed by inhalation of aerosolized bronchodilator such as salbutamol or nicorandil. Six adult mongrel dogs were exposed to intravenous oleic acid (0.08 ml/kg) mixed into a same amount of pure enthanol. We defined a condition of PaO2 less than 60 mmHg in FiO2 0.6 as an acute diffuse lung injury. Lung mechanics were deteriorated after oleic acid injection, from 27.33±2.73 to 17.50±7.47 cmH2O/1/sec in compliance and from 14.55±4.46 to 26.33±6.02 ml/cmH2O in airway resistance. Salbutamol or Nicorandil inhalation significantly improved lung compliance to 30.67±11.30 or 36.33±9.00 cmH2O/1/sec and airway resistance to 16.77±7.47 or 19.55±5.45 ml/cmH2O. From above data, we carefully concluded that compromized lung mechanics in adult respiratory distress syndrome could be effectively managed by inhalation of aerolized bronchodilator.

북한의 유라시아적 전환과 러시아

백준기 조선대학교 통일문제연구소 2003 統一 問題 硏究 Vol.16 No.-

Factitious Fever로 밝혀진 불명열 1예

김백남,강재명,배인규,김양수,우준희,류지소 대한감염학회 2000 감염 Vol.32 No.5

구조물의 안전진단을 위한 충격파의 주파수 영역 탐사에 관한 연구

김형준,이상철,서백수 강원대학교 산업기술연구소 2005 産業技術硏究 Vol.25 No.B

Impact seismic wave method is a method for non-destructive testing of concrete structure using of stress wave which is propagate and reflected from internal flaws within concrete structure and external surface. In this study, we performed frequency domain method using impact seismic wave test for safety diagnosis of civil engineering structure. And reflection method which is used for one-dimensional target such as tunnel lining and transmission method are compared with each other.