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      • Comparison of trophic factors changes in the hippocampal CA1 region between the young and adult gerbil induced by transient cerebral ischemia.

        Yan, Bing Chun,Park, Joon Ha,Kim, Sung Koo,Choi, Jung Hoon,Lee, Choong Hyun,Yoo, Ki-Yeon,Kwon, Young-Geun,Kim, Young-Myeong,Kim, Jong-Dai,Won, Moo-Ho Kluwer Academic/Plenum Publishers 2012 Cellular and molecular neurobiology Vol.32 No.8

        <P>In the present study, we investigated neuronal death/damage in the gerbil hippocampal CA1 region (CA1) and compared changes in some trophic factors, such as brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF) and vascular endothelial growth factor (VEGF), in the CA1 between the adult and young gerbils after 5 min of transient cerebral ischemia. Most of pyramidal neurons (89%) were damaged 4 days after ischemia-reperfusion (I-R) in the adult; however, in the young, about 59% of pyramidal neurons were damaged 7 days after I-R. The immunoreactivity and levels of BDNF and VEGF, not GDNF, in the CA1 of the normal young were lower than those in the normal adult. Four days after I-R in the adult group, the immunoreactivity and levels of BDNF and VEGF were distinctively decreased, and the immunoreactivity and level of GDNF were increased. However, in the young group, all of their immunoreactivities and levels were much higher than those in the normal young group. From 7 days after I-R, all the immunoreactivities and levels were apparently decreased compared to those of the normal adult and young. In brief, we confirmed our recent finding: more delayed and less neuronal death occurred in the young following I-R, and we newly found that the immunoreactivities of trophic factors, such as BDNF, GDNF, and VEGF, in the stratum pyramidale of the CA1 in the young gerbil were much higher than those in the adult gerbil 4 days after transient cerebral ischemia.</P>

      • 인체 공중 동작 시뮬레이션 프로그램 개발

        성낙준,권영후 한국운동역학회 1994 한국운동역학회지 Vol.4 No.2

        A comprehensive simulation software package was developed in C base on the work done by Yeadon et al.(1990) and Kwon (1993a) in the aim of making it easy to apply the experimental simulation technigues to the human airborne movement studies. This package consists of 3 programs: simulation variable computation program (PREP), simulation program (SIM) and the 3-dimensional graphic program (3DMAN). All programs are driven by an easy-to-use menu system and written compatible to KWON3D Motion Analysis Package Version 2.1 (Kwon, 1993b). Program PREP consists of 4 menus: `Edit Data´, `Prepare´ `Angular Momentum´ and `Optimization´. The `Edit Data´ environment is an editor for the lengths of the segments and body lines. The `Prepare´ menu computes the internal orientation angles of the segments while the `Angular Momentum´ menu computes the mean airborne angular momentum of the body and other initial conditions such as the initial position and velocity of the body CM and the initial external orientation of the body. The `Optimization´ menu performs angular momentum optimization proposed by Kwon (1993a). A geometric 15-segment body model - Yeadon-Kwon model (Kwon, 1993b) - with at most 38 degrees of freedom including 3 external orientation angles (somersault, inclination and twist angles) was employed to compute the simulation variables. SIM consists of 2 menus: `Edit Angles´ and `Simulate´. The `Edit Angles´ environment is an editor for the internal orientation angles of the segments. Users can intentionally manipulate the internal orientation angles for the simulation of modified trials. The program displays time-angle curves segment by segment. The `Simulate´ menu actually performs simulation. The initial conditions can be directly manipulated in the program menu environment. The simulation program was tested by several theoretical configurations to screen out the flaws in the theory and to isolate coding mistakes. The simulated results were compared with the predicted results and the program showed good agreements between the simulated results and the theoretical predictions. The simulation program was then applied to several gymnastic maneuvers and springboard dives for testing. 3DMAN was developed in the extension of the traditional `Stick Figure´ graphics. The program is segment-oriented and the 3-D shape of each segment is defined defined independently in a graphic model file to allow the users to use different body models with different, combinations of segments. The model file was designed easy to edit so as to allow the users to change the graphic model easily to meet their specific needs. The graphic model file can be edited using any text editor such as `EDIT´ of DOS. Once the `3-D Graphics´ option is activated followed by the registration of the graphic model files, the program draws the 3-D shapes of the segments whose model files are registered. All the graphics-related menus including registration of the segment graphic model files are accessible within the graphic environment.

      • SCIESCOPUSKCI등재

        AN IN-SITU YOUNG'S MODULUS MEASUREMENT TECHNIQUE FOR NUCLEAR POWER PLANTS USING TIME-FREQUENCY ANALYSIS

        Choi, Young-Chul,Yoon, Doo-Byung,Park, Jin-Ho,Kwon, Hyun-Sang Korean Nuclear Society 2009 Nuclear Engineering and Technology Vol.41 No.3

        Elastic wave is one of the most useful tools for non-destructive tests in nuclear power plants. Since the elastic properties are indispensable for analyzing the behaviors of elastic waves, they should be predetermined within an acceptable accuracy. Nuclear power plants are exposed to harsh environmental conditions and hence the structures are degraded. It means that the Young's modulus becomes unreliable and in-situ measurement of Young's modulus is required from an engineering point of view. Young's modulus is estimated from the group velocity of propagating waves. Because the flexural wave of a plate is inherently dispersive, the group velocity is not clearly evaluated in temporal signal analysis. In order to overcome such ambiguity in estimation of group velocity, Wigner-Ville distribution as the time-frequency analysis technique was proposed and utilized. To verify the proposed method, experiments for steel and acryl plates were performed with accelerometers. The results show good estimation of the Young's modulus of two plates.

      • 젊은 성인에서 흡연에 의한 상완동맥 내피기능의 부전에 관한 연구

        이상철,권영주,방덕원,이선해,이보영,김지욱,김영훈,온영근,현민수,김성구 순천향의학연구소 2002 Journal of Soonchunhyang Medical Science Vol.8 No.1

        Background and Objectives : Cigarette smoking is a major factor and the most modifiable risk factor for atherosclerosis. Endothelial dysfunction is an early event in atherosclerosis, before the structural change of the systemic arteries. We hypothesized that endothelial dysfunction might be present in the systemic arteries of young adult smokers and that this might be dose-dependent phenomenon. Therefore, we try to certify that smoking is associated with endothelial dysfunction in healthy young adults without other risk factor of atherosclerosis. Subjects and Methods : we studied noninvasively 29 subjects aged 3 to 4 decades without other risk factor of atherosclerosis, they were composed of the two groups, current smokers(n=15) and nonsmokers(n=14). Smoking history varied from 3 to 20 pack years. Using high-resolution ultrasound, vessel diameter and mean flow rate were measured at rest, during reactive hyperemia(with flow-mediated endothelium-dependent dilation), and after sublingual nitroglycerin(NG-induced endothelium-independent vasodilation). Result : Flow mediated endothelium dependent dilation was observed in the control subjects (9.4±3.44%) but was impaired in the smokers(5.8±2.51%)(p=0.004). NG-induced endothelium independent dilation is no difference in all subjects. Conclusion : Cigarette smoking is associated with endothelial dysfunction in healthy young adults.

      • 만선신부전 환자에서 관상동맥조영술 소견에 관한 연구

        한대희,김성구,박상호,김성한,조원영,방덕원,조윤행,정의룡,은영근,권영구 순천향의학연구소 2003 Journal of Soonchunhyang Medical Science Vol.9 No.1

        Background : Patients with chronic renal fialure have a substantially elevated risk of death from cardiovascular diseases than do the general population. the patients with chronic renal failure are at significantly increased freqeuncy of hypertension, hyperlipidemia, and diabetes mellitus which are known to the risk factors of the coronary artery diseases, and the prevalence of the coronary artery diseases in chronic renal failure patients is highly associated with the hemodynamic disorder and metabolic abnormalities. therefore we expected that the coronary angiographic findings in patients with chronic renal failure should be different from the general population (control groups) and investigated the risk factors contributing to coronary artery diseases. Method : we have retrospectively compared the coronary angiographic findings of 44 patients with chronic renal failure on hemodialysis with that of 88 patients in the general population and investigated the factors contributing to the development and acceleration of coronary artery diseases in patients with chronic renal failure Result : Hypertension and diabetes mellitus which is risk factors for coronary artery disease is significantly increased in patients with chronic renal failure, in coronary angiographic finding the severity of the lesion is worse. the incidence of PCI or CABG of patients with chronic renal failure is more than that of control group but statistically no difference between patients with chronic renal failure and control group. the sex, the duration of disease, the duration of dialysis, serum creatinine in patients with chronic renal failure have no correlation to the prevalence of coronary artery disease and severity of lesion. hyperglycemic patients with chronic renal failure have high incidence of coronary artery disease and are worse in the severity of lesion Conclusions : There is significantly increased the pevalence and severity of involving multiple coronary artery diseses in hyperglycemic patients with CRF.

      • 노화가 인체 중간엽 줄기세포로부터 조골세포로의 증식 및 분화에 미치는 영향

        백기현,태현정,오기원,이원영,조정기,권순용,강무일,차봉연,이광우,손호영,강성구,김춘추 대한내분비학회 2003 Endocrinology and metabolism Vol.18 No.3

        연구배경: 일반적으로 골다공증과 연관된 위험인자로는 연령, 폐경, 약물, 불충분한 칼슘섭취, 만성질환 및 운동부족 등이 있는데, 특히 노화가 진행할수록 골밀도가 감소하는 것은 잘 알려져 있다. 노화와 관련하여 진행되는 골소실은 조골세포 및 전구조골세포의 기능적 결핍에 의한 골형성의 감소가 주요한 요인으로 여겨지고 있다. 그 동안 연령이 조골모 세포의 양과 조골모 세포로부터 성숙조골세포로의 분화 및 증식에 미치는 영향에 대한 일부 보고들이 있었으나 아직 일치된 견해는 없는 형편이다. 방법: 다양한 연령의 사람으로부터 골수를 채취, 중간엽 줄기세포가 포함된 단핵세포를 분리한 후 조골세포로 분화하기 좋은 조건하에서 배양하였다. 대상군은다시 젊은군과 노령군으로 구분하여 다양한 변수를 비교 분석하였다. 일차배양에서는 CFU-F를 계수하여 골수내 중간엽 줄기세포의 수를 추산하였고, 칼슘측정을 통하여 기질의 무기화 정도를 비교하였다. 계대배양후 이차배양에서는 시기별로 알카리성 포스파타제 활성도를 측정하고 오스테오칼신 mRNA의 발현을 관찰하여 젊은군과 노령군 사이의 증식능 차이를 비교하였다. 또한 이차배양 시기별로 MTT 측정을 하여 양군간에 증식능 차이가 있는지 알아보았다. 결과: 1. 일차배양 15일째에 평균 CFU-F의 수는 젊은군에서 유의하게 많았다(젊은군 148.3±28.9, 노령군 54.3±9.1, p=0.02). CFU-F의 평균면적은 젊은군에서 넓은 경향을 보였으나 통계적으로 유의하지는 않았다. 2. 일차배양 17일 경과 후 양군간에 기질 칼슘 침착정도는 유의한 차이를 보이지 않았다(젊은군 103.6±50.6, 노령군: 114.0±56.5, p=NS). 3. 이차배양 10일째에 젊은군에서 알카리성 포스파타제 활성도가 고령군에 비해 유의하게 높았다(젊은군: 935.5±115.0 U/mg, 노령군: 578.4±115.7U/mg,p.0.05). 고령군에서는 시간 경과에 따른 변화가 미약했으며 전반적으로 알카리성 포스파타제의 활성도가 젊은군에 비해 낮았다. 4. 이차배양도중 오스테오칼신 mRNA의 발현은 배양시기별로 젊은군에 비해 고령군에서 더 낮은 경향을 관찰할 수 있었다. 5. 이차배양 10일과 15일에 젊은군에서 노령군보다세포증식이 유의하게 증가된 양상을 보였다(10앓 젊은군 0.73±0.05, 노령군 0.58±0.04, p=0.05, 15일; 젊은군 0.80±0.05, 노령군 0.70±0.03, p=0.05).결론: 이상의 연구에서 저자들은 노령군에서 젊은군보다 골수 내 중간엽줄기세포의 수가 적고, 노령군에서 유래한 전구조골세포의 성숙조골세포로의 증식 및 분화가 젊은군 보다 감소해 있는 것을 관찰할 수 있었다. Background: Osteoblasts originate from osteoprogenitor cells in bone marrow stroma, termed mesenchymal stem cells (MSCs) or bone marrow stromal cells. Each MSC forms colonies (colony forming units-fibroblasts [CFL-Fs]) when cultured ex vivo. There are some reports about the age-related changes of the number and osteogenic potential of osteoprogenitor cells, but any relationship has not been clearly established in humans. In this study, we counted MSCs using CFU-Fs count and examined the proliferative capacity and differentiation potential of osteoprogenitor cells. Finally, we analyzed how these parameters varied with donor age. Methods: Bone marrow was obtained from the iliac crest of young (n=6, 27.2±8.6 years old) and old (n= 10, 57.4k6.7 years old) healthy donors. Mononuclear cells, including MSCs, were isolated and cultured in osteogenic medium. In primary culture, we compared the colony-forming efficiency of MSCs between the two groups and determined the matrix calcification. When primary culture showed near confluence, the cells were subcultured. Alkaline phosphatase activity, osteocalcin expression by RT-PCR and proliferative potential by MTT assay were examined by the time course of secondary culture. Results: At the 15th day of primary culture, the mean number of CFU-Fs was significantly higher in the younger donors (young: 148.3±28.9, old: 54.3±9.1, p=0.02) and the mean size of CFL-Fs was also larger in the younger donors than the older donors. However, matrix calcification was not different between the two groups (young: 103.6±50.6, old: 114.0±56.5, p=NS). In secondary culture, alkaline phosphatase activities were significantly lower in the older donors. The younger donors showed peak alkaline phosphatase activity at day 10, while the older donors didn't showed a remarkable peak (young: 935.5±115.OU/mg, old: 578.4±115.7U/mg, p<0.05). Total cell number as a proliferative index increased progressively during the secondary culture and a significantly greater cell number was noted in the younger donors. Osteocalcin expression was generally upregulated in the younger donors, but this was not statistically significant. Conclusion: Our study shows that the number of osteoprogenitor cells is decreased during aging and that the proliferative capacity and differentiation potential of osteoprogenitor cells seem to be reduced during aging (J Kor SOC Endocrinol 18:296-305, 2003).

      • 현대건축의 형태표현에 나타난 '낯설게 하기(defamiliarization)'의 경향에 관한 연구

        권유경,김성우,김영태 영남대학교 환경문제연구소 2000 環境硏究 Vol.19 No.2

        본 연구는 1920년 러시아 문학의 현상으로 나타난 '낯설게 하기'의 이념을 현대건축의 조형표현 및 이론적 상관성으로 관련짓고자 한다. 현대건축에 있어서 중요한 이해와 경향인 '낯설게하기'를 통해 재발견되는 형식적인 표현으로써 현대건축에서 직접적 혹은 간접적으로 인용되고 있다. 내용보다 형식의 문제에 주목했던 러시아 형식주의의 '낯설게(defamiliarization)'을 통하여 현대건축에서 나타나고 있는 복잡성, 다양성, 혼성, 애매성 등을 제(諸)특성으로 보고, '낯설게 하기'의 목적과 수법들을 조형예술의 표현 특성 및 조형이념과 관련하여 건축적인 체계로 유형화하고 현대건축에서 나타나고 있는 경향 및 형태표현을 파악하는데 그 의의를 두고자 한다. This study related the idea of 'defamiliarization' in 1920's Russian Literature to the phenomenon of modern architecture and analyzed formative expression and theoretical correlativity. It is significant to understand the tendency of modern 'defamiliarization' which has comparatively been cited many times and expressed directly or indirectly in modern architecture. Expecially the 'defamiliarization' theory, with the experimental spirit of Russia constructivism, connected to formative art and can be related to the feature of complexity, variety, perplexity, conceptualization which are prominent in modern architecture. The meaning of 'defamiliarization' involves all the meanings of something new, creative, progressive and throughout this pursuing destruction of fixed idea, inhered newness, deautomatism in the process of consciousness usual environment, subconsciousness. This become the motive which formed important basis of making a new ideology in the formative art since Avant-garde and this logic offers theoretical basis correlated the Avant-garde spirit as a stream of breaking the existing convention.

      • Media를 충전한 간섭포기식 침지여상에 의한 흐름특성에 관한 연구

        權泳浩,梁相鉉 全北大學校 1994 論文集 Vol.37 No.-

        The flow pattern characteristics of submerged biofilters filled with three kinds of filter media were experimentally examined, and obtained results are as follows. 1. Flow patterns in submerged biofilters filled with three kinds of filter media was nearly complete mixing type when the parts of effluent are recycled, and nearly plug flow type without recycle. 2. Dispersion numbers of the flow recirculated was appeared 0.1352-0.2008 for A media 0.1156-0.1799 for B media and 0.1436-0.2035 for C media, respectively. Dispersion numbers of the flow not recirculated was appeared 0.0257-0.0614 for A media. 0.0122-0.0437 for B media and 0.0428-0.0762 for C media, respectively.

      • SCOPUSSCIEKCI등재

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