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복합재료 이론에 의한 2차원 상판 구조물의 정확하고 간단한 해석
김준민,한봉구 서울산업대학교 2005 논문집 Vol.54 No.2
대부분의 건설기술자들은 강판형교나 콘크리트 교량을 단위 폭을 가진 보로 해석 하나 이러한 구조물은 엄연히 복합재료로 이루어진 판(plate) 구조이다. 이러한 구조물은 균등단면에 등분포하중을 받고 4변 단순 지지된 경우가 아니면 정확한 해석이 불가능하다. 복합 재료의 이론은 일반 기술자들이 이해하기 힘드나, 본 논문에서는 이러한 문제를 비교적 쉽게 정확히 해석하는 방법을 제시하고, 예로서 3경간 연속 판 교량과 포스트텐션된 강교의 해석을 보여준다.
운동성 산화 스트레스와 항산화비타민의 보충이 말초단핵세포의 NF-kB 활성에 미치는 영향
진영수,박건구,박준영,김미정,이왕록,김혜영,이한준,박은경 대한스포츠의학회 2000 대한스포츠의학회지 Vol.18 No.2
Reactive oxygen species(ROS) are implicated in the pathogenesis of a wide variety of human diseases. Numerous studies indicate that ROS may serve as common intracellular molecules that contribute to the process of nuclear factor(NF)κB activation in response to a diverse stimuli. In our laboratory, we have demonstrated tat antioxidants could reverse the decline of immune function caused by exercise-induced ROS. Furthermore, it in necessary to understand a mechanism underlying ROS-dependent disorder in biological system. Recent studies have been shown that several gene expression were regulated by oxidants, antioxidants and other determinants of the intracellular reduction-oxidation(redox) state. In this process, NF-κB have been shown to play a important role. The purpose of the present investigation was to evaluate the effect of exercise-induced oxidative stress and antioxidnt supplementation on NF-κB activation in peripheral mononuclear cells. Forty male SD rats(4 weeks old) were randomly divided into noraml diet group and antioxidants(ATO) supplement group, and then ATO groups were treated with antioxidants(VE: 2001U/kg, VC: 50mg/rat, β-carotene: 300mg/kg, vitamin B6: 250㎍/100g, selenomethionine: 0.1mg/kg) for 16 weeks. After 16 weeks breeding at each condition, each group divided into two groups: Control group(CR) fed generally, Exercise group(CE) fed generally and followed by acute exercise 16 weeks later. Antioxidant Antioxidants and Exercise group(AE) fed with antioxidants and followed by acute exercise. The activation of NF-κB binding activity was increased after exhaustive exercise bout in both group. In addition, pretreatment of ATO group with the antioxidants mixture lead to the inhibition of NF-κB binding activity. This results suggest that NF-κB activation should be further studies in response to a variety of exercise.
신영수,김창엽,오병희,한규섭,윤병우,한준구,강영호 한국의료QA학회 1997 한국의료질향상학회지 Vol.4 No.1
Background : With increased concerns about variation among physician a practice pattern and their impact on the quality of care, clinical practice guidelines have been developed by many different organizations, with differing aims and incentives. From the same point of view, there is growing interest in the development of clinical practice guidelines in Korea, but with only a few examples. As a result, there is not much exploration on the incentive and barrier to development guidelines as well as description on the development process. The purposes of this study are to describe the process of the four different clinical practice guidelines in a hospital setting, and to identify incentives and barriers in the development of guidelines. Methods : For this research, a clinical practice guideline development committee and four clinical practice guideline development teams were organized in a university hospital which has more than 1,200 beds. Twenty eight doctors, three nurses, and one technician participated as members of development teams for eight months. Four to six meetings were held, and three to seven departments in the hospital were involved. Results : The topics which developed into clinical practice guidelines were cardiopulmonary resuscitation(CPR), blood transfusion, anticoagulation, and angiography. The main goals set by teams were education(CPR, angiography), risk management(blood transfusion), and to enhance quality of care(anticoagulation). Among four teams, only in the team for anticoagulation guideline medical record review and pilot-testing were performed. Also literature review was not carried out systematically. However, all the guidelines were developed by multidisciplinary participation by personnels of related departments. All the team expected guidelines to be used as standard protocols in the practice. Conclusion : Experience and skill in developing process has to be improved to have a more valid and useful practice guideline. In particular, literature review and problem identification by examining medical record should be emphasized. Also further studies of the clinical outcomes of the guidelines application and changes in physicians behaviors would be required.
Contrast Media in Abdominal Computed Tomography: Optimization of Delivery Methods
Joon Koo Han,Byung Ihn Choi,Ah Young Kim,Soo Jung Kim The Korean Society of Radiology 2001 Korean Journal of Radiology Vol.2 No.1
Objective: To provide a systematic overview of the effects of various parameters on contrast enhancement within the same population, an animal experiment as well as a computer-aided simulation study was performed. Materials and Methods: In an animal experiment, single-level dynamic CT through the liver was performed at 5-second intervals just after the injection of contrast medium for 3 minutes. Combinations of three different amounts (1, 2, 3 mL/kg), concentrations (150, 200, 300 mgI/mL), and injection rates (0.5, 1, 2 mL/sec) were used. The CT number of the aorta (A), portal vein (P) and liver (L) was measured in each image, and time-attenuation curves for A, P and L were thus obtained. The degree of maximum enhancement (Imax) and time to reach peak enhancement (Tmax) of A, P and L were determined, and times to equilibrium (Teq) were analyzed. In the computed-aided simulation model, a program based on the amount, flow, and diffusion coefficient of body fluid in various compartments of the human body was designed. The input variables were the concentrations, volumes and injection rates of the contrast media used. The program generated the time-attenuation curves of A, P and L, as well as liver-to-hepatocellular carcinoma (HCC) contrast curves. On each curve, we calculated and plotted the optimal temporal window (time period above the lower threshold, which in this experiment was 10 Hounsfield units), the total area under the curve above the lower threshold, and the area within the optimal range. Results: A. Animal Experiment: At a given concentration and injection rate, an increased volume of contrast medium led to increases in Imax A, P and L. In addition, Tmax A, P, L and Teq were prolonged in parallel with increases in injection time The time-attenuation curve shifted upward and to the right. For a given volume and injection rate, an increased concentration of contrast medium increased the degree of aortic, portal and hepatic enhancement, though Tmax A, P and L remained the same. The time-attenuation curve shifted upward. For a given volume and concentration of contrast medium, changes in the injection rate had a prominent effect on aortic enhancement, and that of the portal vein and hepatic parenchyma also showed some increase, though the effect was less prominent. A increased in the rate of contrast injection led to shifting of the time enhancement curve to the left and upward. B. Computer Simulation: At a faster injection rate, there was minimal change in the degree of hepatic attenuation, though the duration of the optimal temporal window decreased. The area between 10 and 30 HU was greatest when contrast media was delivered at a rate of 2 3 mL/sec. Although the total area under the curve increased in proportion to the injection rate, most of this increase was above the upper threshould and thus the temporal window was narrow and the optimal area decreased. Conclusion: Increases in volume, concentration and injection rate all resulted in improved arterial enhancement. If cost was disregarded, increasing the injection volume was the most reliable way of obtaining good quality enhancement. The optimal way of delivering a given amount of contrast medium can be calculated using a computer-based mathematical model.