• The Korean Journal of Physiology and Pharmacology
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• 제17권4호
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• pp.283-289
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• 2013

This study was designed to evaluate the protective effect of Korean red ginseng (KRG) against ischemia/reperfusion (I/R) injury in isolated guinea pig heart. KRG has been shown to possess various ginsenosides, which are the major components of Panax ginseng. These components are known naturally occurring compounds with beneficial effects and free radical scavenging activity. The heart was induced to ischemia for 60 min, followed by 120 min reperfusion. The hearts were randomly allocated into five groups (n=8 for each group): normal control (N/C), KRG control, I/R control, 250 mg/kg KRG group and 500 mg/kg KRG group. KRG significantly increased hemodynamics parameters such as aortic flow, coronary flow and cardiac output. Moreover, KRG significantly increased left ventricular systolic pressure (LVSP), the maximal rate of contraction (+dP/$dt_{max}$) and maximal rate of relaxation (-dP/$dt_{max}$). Also, treatment of KRG ameliorated electrocardiographic index such as the QRS, QT and RR intervals. Moreover, KRG significantly suppressed the lactate dehydrogenase, creatine kinase-MB fraction and cardiac troponin I and ameliorated the oxidative stress markers such as malondialdehyde and glutathione. KRG was standardized through ultra performance liquid chromatograph analysis for its major ginsenosides. Taken together, KRG has been shown to prevent cardiac injury by normalizing the biochemical and oxidative stress.

• The Korean Journal of Physiology
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• 제24권1호
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• pp.115-121
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• 1990

Pentobarbital 마취한 정상혈압 및 신성 고혈압 흰쥐에서 calcium channel 봉쇄 약물 nifedipine과 atrial natriuretic peptide(ANP)의 상호작용을 조사하였다. 정상혈압 흰쥐에서 nifedipine$(1.0\;{\mu}g/kg/min)$ 또는 ANP(60 ng/kg/min)의 주입은 각각 유의하게 혈압을 내렸으며 두 약물의 동시 주입시에 개별적으로 주입하였을 때보다 그 혈압내림의 정도가 더욱 컸다. Nifedipine은 단독 주입하였을 때에 신기능에 유의한 영향을 미치지 않았으나 ANP와 동시에 주입하였을 때에는 ANP의 요량 및 Na 배설 증가 효과를 항진시켰다. 한편 고혈압 흰쥐에서도 ANP의 혈압내림효과와 신장효과는 nifedipine과 함께 주입하였을 때에 더 컸다. 적출 흉부대동맥 표본을 phenylephrine으로 미리 수축시킨 후 ANP를 첨가하면 용량의존 이완반응을 보였고 nifedipine 존재하에서 더 예민하였다. 이상의 실험결과는 calcium channel 봉쇄약물이 ANP의 혈압내림효과를 항진시킴을 보인 것이며 그 기전으로 요중 배설 증가 및 혈관이완효과 증가 등이 관여함을 시사하였다.

• 한국수소및신에너지학회논문집
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• 제26권2호
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• pp.120-126
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• 2015

Recently, the ever-increasing use of fossil fuels for rapid industrial development and population significantly caused an environment pollution and global warming such as climate change. So research and development of sustainable and eco-friendly energy have been performed. Especially the interest in nuclear fusion fuel was significantly increased from the developed countries. The system of fusion energy production was tritium separation, storage and delivery, and purification. Republic of Korea is in charge of Storage and Delivery System (SDS) in the International Thermonuclear Experimental Reactor (ITER). Welding part of the SDS bottles for storing the tritium is known to be susceptible to hydrogen embrittlement. In this study, conducted a study for the relaxation of the stability and hydrogen embrittlement of the weld area. The hydrogen heat treatment was processed through the Pressure-Composition-Temperature (PCT) device according to the time variation. Also mechanical properties such as impact test and hardness test according to using the alkaline cleaning liquid for hydrogen embrittlement relief and the fracture was observed by scanning electron microscopy (SEM) after the mechanical properties evaluation.

• 대한한의학방제학회지
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• 제21권1호
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• pp.119-130
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• 2013

Objectives : Diabetes mellitus is the leading cause for vascular complications such as atherosclerosis. The present study is to investigate whether Doinseunggi-tang (DST) improves diabetic vascular dysfunction in type II diabetes. Methods : The db/db mice were treated with high fat/high cholesterol diet and DST (200 mg/kg/day) for 8 weeks. Results : DST significantly lowered blood glucose and systolic blood pressure. In addition, DST also markedly decreased total plasma cholesterol, triglyceride, and LDL-cholesterol, whereas increased the HDL-cholesterol. Vascular relaxation of aortic rings by acetylcholine or SNP was ameliorated by DST in a dose-dependent manner. Damage of vascular intima and hypertrophic of media was improved by DST. Immunohistological study revealed that DST attenuated the increase of ICAM-1, VCAM-1, and ET-1 expression in thoracic aorta. Conclusions : Taken together, DST suppressed hyperglycemia and diabetic vascular dysfunction in type II db/db mice. The present data suggests that Doinseunggi-tang may be prevent a development of diabetic atherosclerosis.

• 전자공학회논문지D
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• 제35D권10호
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• pp.83-90
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• 1998

MOS 캐패시터의 게이트 전극을 비정질 상태의 실리콘으로 형성하여 GOI(Gate Oxide Integrity)특성에 미치는 불순물 활성화 열처리의 효과를 조사하였다. LPCVD(Low Pressure Chemical Vapor Deposition) 방법으로 증착한 비정질 실리콘 게이트 전극은 활성화 열처리에 의하여 다결정 실리콘 상태로 구조가 변화하며, 불순물 원자의 활성화가 충분히 이루어졌다. 또한, 비정질 상태의 게이트 전극은 커다란 압축 응력(compressive stress)을 가지지만, 활성화 열처리 온도가 700℃에서 900℃로 증가함에 따라서 응력이 완화되었고 게이트 전극의 저항도 감소하는 특성을 보였다. 또한 얇은 게이트 산화막의 신뢰성 및 산화막의 계면특성은 활성화 열처리 온도에 크게 의존하고 있었다. 900℃에서 활성화 열처리를 한 경우가 700℃에서 열처리한 경우보다 산화막내에서의 전하 포획 특성이 개선되었으며, 산화막의 신뢰성이 향상되었다. 특히, TDDB 방법으로 예측한 게이트 산화막의 수명은 700℃의 열처리에서는 3×10/sup 10/초였지만, 900℃에서의 열처리에서는 2×10/sup 12/초로 현저하게 개선되었다. 그리고, 산화막 계면에서의 계면 전하 밀도는 게이트의 응력 완화에 따라서 개선되었다.

• 약학회지
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• 제59권4호
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• pp.158-163
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• 2015

Cardiac myocytes are subjected to fluid shear stress during each contraction and relaxation. Under pathological conditions, such as valve disease, heart failure or hypertension, shear stress in cardiac chamber increases due to high blood volume and pressure. The shear stress induces proarrhythmic longitudinal global $Ca^{2+}$ waves in atrial myocytes. In the present study, we further explored underlying cellular mechanism for the shear stress-induced longitudinal global $Ca^{2+}$ wave in isolated rat atrial myocytes. A shear stress of ${\sim}16dyn/cm^2$ was applied onto entire single myocyte using pressurized fluid puffing. Confocal $Ca^{2+}$ imaging was performed to measure local and global $Ca^{2+}$ signals. Shear stress elicited longitudinally propagating global $Ca^{2+}$ wave (${\sim}80{\mu}m/s$). The occurrence of shear stress-induced atrial $Ca^{2+}$ wave was eliminated by the inhibition of ryanodine receptors (RyRs) or inositol 1,4,5-trisphosphate receptors ($IP_3Rs$). In addition, pretreatment of phospholipase C (PLC) inhibitor U73122, but not its inactive analogue U73343, abolished the generation of longitudinal $Ca^{2+}$ wave under shear stress. Our data suggest that shear-induced longitudinal $Ca^{2+}$ wave may be induced by $Ca^{2+}$-induced $Ca^{2+}$ release through the RyRs which is triggered by $PLC-IP_3R$ signaling in atrial myocytes.

• 한국실내디자인학회논문집
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• 제22권1호
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• pp.164-173
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• 2013

This study aims to analyze the aesthetic thought and expression tendency appeared in contemporary architecture by looking at today's architectural art based on the concept of the uncanny that Sigmund Freud contended as an aesthetic principle, of the aesthetic concepts tossed around to define the contemporary times in the aesthetics field and discuss the architectural analysis possibility of the concept of the uncanny. The generation structure of the uncanny that generates experiences of fear and surprise is classified into dual structure, trauma, threatening structure, and repetition compulsion. This is the principle that evokes a sense of experiencing subject, incorporates sensibility, and vitalizes internal process. This is also the methodology to organize and structure the concept of the uncanny. When seen from the four factors drawn from the concept of the uncanny and aesthetic expressions, the uncanny expression characteristics of contemporary architecture includes isolation, subversion, trace, absence, oblique line, flotation, concealment, and disturbance. Isolation and subversion refers to producing the space of the pressure of tension and relaxation caused by repression and relief from repression and eliciting the maximum expansion of the sense of space through spatial change. Trace and absence indicates being able to elicit more intense emotions from the experiencing subject by applying the images of alienation and absence in the way to reproduce historical trauma. This happens by implementing the potential value of physical activity. Oblique line and flotation means visual impulse. This happens in the way to visualize uneasy points. This causes uncanny by threatening the survival. Finally, concealment and disturbance refers to creating unpredictable space. The concept of masquerade and maze space composition are applied in the way to activate spatial perception, including space exploration and unintended subject's forced selection. As stated above, the uncanny expression characteristics shown in contemporary architecture can be presented as indicators that are available to analyze the undecided and diversified contemporary architecture aesthetically. In this respect, this study has great significance.

• 터널과지하공간
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• 제19권5호
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• pp.388-396
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• 2009

록볼트는 지하공동 굴착시 암반의 과도한 이완을 초기에 방지할 수 있는 가장 중요한 터널 지보재 중 하나이다. 국내외에서 록볼트의 설치에 따른 침하저감 및 보강효과, 다양한 록볼트 형태에 따른 터널 안정성 증대효과 등 록볼트 지보효과에 대한 많은 연구는 있으나, 록볼트에 긴장력을 가함으로써 절리암반의 지반보강 효과에 대한 연구는 미흡한 실정이다. 본 연구에서는 수평절리암반을 모사한 모형지반에서 록볼트의 긴장력 및 설치간격을 변수로 하여 대형모형실험을 실시하여, 록볼트에 의한 지반 보강효과를 확인하였다. 록볼트의 긴장력에 의한 절리암반 보강효과를 확인하기 위하여 단순보를 조성하여 긴장력과 설치간격을 변수로 하였다. 굴착에 따른 모형지반 중앙하부 처짐량을 측정하여 록볼트로 보강된 보강영역의 지반변형계수를 도출하였다.

• 대한기계학회논문집B
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• 제29권11호
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• pp.1265-1276
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• 2005

The elliptic conceptual second moment models for turbulent heat fluxes, which are proposed on the basis of elliptic-blending and elliptic-relaxation equations, are applied to calculate the combined forced and natural turbulent convection in a vertical plane channel. The models satisfy the near-wall balance between viscous diffusion, viscous dissipation and temperature-pressure gradient correlation, and also have the characteristics of approaching its respective conventional high Reynolds number model far away from the wall. Also the models are closely linked to the elliptic blending model which is used for the prediction of Reynolds stress. In order to calibrate the heat flux models, firstly, the distributions of mean temperature and scala flux in fully developed channel flow with constant wall difference temperature are solved by the present models. The buoyancy effect on the turbulent characteristics including the mean velocity and temperature, the Reynolds stress tensor, and the turbulent heat flux vector are examined. In the opposing flow, the turbulent transport is greatly enhanced with both the Reynolds stresses and the turbulent heat fluxes being remarkably increased; whereas, in the aiding flow, the opposite change is observed. The results of prediction are directly compared to the DNS to assess the performance of the model predictions and show that the behaviors of the turbulent heat transfer in the whole flow region are well captured by the present models.

• 한국응급구조학회지
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• 제23권3호
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• pp.67-81
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• 2019

Purpose: The purpose of this study was to compare the difference in compression quality and fatigue levels in a rescuer for three different hand techniques used in cardiopulmonary resuscitation (CPR). Methods: The participants were paramedic students at the basic life support provider level. The hands-only CPR was performed for 10 minutes for each of the three hand techniques without disruption, and the quality of chest compressions and fatigue levels were analyzed. Results: There was no difference between the sexes in the chest compression quality and the physiologic parameters before and after compression. Among the quality indexes of chest compression with each of the techniques performed for 10 minutes, the mean depth (p<.01) and mean accuracy (p=.000) of the compression were found to be higher in the five finger fulcrum technique, while the mean compression rate and relaxation accuracy showed no significant differences. Regarding fatigue levels, the five finger fulcrum technique caused lesser subjective fatigue as compared to other techniques (p<.05), although the heart rate and blood pressure revealed no difference. Conclusion: The five finger fulcrum technique was found to be better than the other techniques in terms of chest compression quality and subjective levels of fatigue, indicating that it should be used in CPR education.