• 동의생리병리학회지
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• 제19권6호
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• pp.1573-1579
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• 2005

This study was undertaken to define the effect of DaeSiHo-Tang extract on the hypertension in spontaneous hypertensive rat and norepinephrine-induced arterial contraction in rabbit. Systolic blood pressure and blood velocity were significantly attenuated by administration of DaeSiHo-Tang extract. but blood flow and renin-angiotensin-aldosterone system unaffected by DaeSiHo-Tang extract. The relaxation effect of DaeSiHo-Tang extract was dependent on the presence of endothelium, showing that DaeSiHo-Tang extract-induced relaxation was not observed in the strips without endothelium. The endothelium-dependent relaxation induced by DaeSiHo-Tang extract was decreased by the pretreatment of $N{\omega}$-nitro-L-arginine or methylene blue, but it was not observed in the strips pretreated with indomethacin or tetraethylammonium chloride. When $Ca^{2+}$ was applied, the strips which were contracted by norepinephrine in a $Ca^{2+}$-free solution, arterial contraction was increased. But pre-treatment of DaeSiHo-Tang extract inhibited contractile response to $Ca^{2+}$. These results indicate that antihypertensive effect of DaeSiHo-Tang extract is due to descend arterial resistance by the arterial relaxation through the formation of nitric oxide in the vascular endothelial cells.

• 대한기계학회논문집B
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• 제37권11호
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• pp.985-990
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• 2013

신부전 환자의 신장기능을 유지하는 방법의 일환으로서 사용되는 혈액 투석 시 동정맥루 문합각도에 따라서 혈액 유동상태의 양호가 결정된다. 지금까지의 연구는 CFD에 의한 것이 대부분이었으나 실험적 보고는 없다. 본 연구에서는 동정맥루의 혈류역학적 특성을 분석하기 위하여 PIV기법을 이용하였다. PIV실험을 위한 혈관모델의 문합부 각도는 $30^{\circ}C$로 정하였다. 유체역학적 상사를 만족시키기 위하여 Re수는 같게 하였고, 동맥부분에 밸브를 달아 개폐 정도를 조절하면서 PIV실험을 수행하였다. PIV 실험결과 분지부 부분에서 재순환유동이 발생되는 것을 볼 수 있었고, 동맥의 개폐 정도에 따라 전체적인 혈류속도의 변화가 나타났다.

• Advances in biomechanics and applications
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• 제1권2호
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• pp.127-141
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• 2014

A preliminary study of a new pulsatile pump that will work to a frequency greater than 1 Hz, is presented. The fluid-structure interaction between a Newtonian blood flow and a piston drive that moves with periodic speed is simulated. The mechanism is of double effect and has four valves, two at the input flow and two at the output flow; the valves are simulated with specified velocity of closing and reopening. The simulation is made with finite elements software named COMSOL Multiphysics 3.3 to resolve the flow in a preliminary planar configuration. The geometry is 2D to determine areas of high speeds and high shear stresses that can cause hemolysis and platelet aggregation. The opening and closing valves are modelled by solid structure interacting with flow, the rhythmic opening and closing are synchronized with the piston harmonic movement. The boundary conditions at the input and output areas are only normal traction with reference pressure. On the other hand, the fluid structure interactions are manifested due to the non-slip boundary conditions over the piston moving surfaces, moving valve contours and fix pump walls. The non-physiologic frequency pulsatile pump, from the viewpoint of fluid flow analysis, is predicted feasible and with characteristic of low hemolysis and low thrombogenesis, because the stress tension and resident time are smaller than the limit and the vortices are destroyed for the periodic flow.

• Clinical and Experimental Pediatrics
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• 제49권7호
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• pp.769-776
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• 2006

목 적 : 성인에서 PWV와 ABI는 동맥 경직을 측정할 수 있는 비침습적 방법으로 성인에서 고혈압, 말기 신장병, 동맥경화증의 정도를 평가할 수 있는 유용하고 간단한 방법으로 알려져 있다. 그러나 소아를 비롯한 청소년에서의 연구는 많지 않은 실정이다. 동맥경화증을 포함한 혈관의 변화가 무증상의 상태로 어린 나이에 시작해서 진행되기 때문에 청소년 고혈압, 비만 환자에서 동맥 경직의 평가가 절실하게 필요하다. 본 연구에서는 고혈압 청소년을 정상 청소년과 비교함으로 청소년에서 PWV의 유용성을 평가하고자 하였다. 방 법 : 15-16세의 청소년 413명을 고혈압군(1군 : 23명), 고혈압과 비만이 같이 있는군(2군 : 17명), 정상 대조군(3군 : 328명) 3개의 군으로 나누었다. 신장, 체중, 체질량지수를 측정하였고, Colin사의 VP-1000을 이용하여 사지의 수축기, 이완기, 평균 혈압과 양측 PWV, ABI, ET, PEP를 측정하여 비교분석 하였다. 결 과 : 우측 상완과 발목 사이의 PWV(RbaPWV)는 1군($1,186.4{\pm}134.9cm/sec$)과 2군($1,214.4{\pm}45.8cm/sec$) 모두에서 3군($939.1{\pm}84.3cm/sec$)에 비해 유의하게 높았으며(P<0.05), 2군에서 1군에 비해 유의하게 높았다(P<0.05). 좌측 상완과 발목사이의 PWV(LbaPWV) 또한 1군($1,198.4{\pm}99.8cm/sec$)과 2군($1,219.7{\pm}43.2cm/sec$) 모두에서 3군($942.1{\pm}75.8cm/sec$)에 비해 유의하게 높았으며(P<0.05), 2군에서 1군에 비해 유의하게 높았다(P<0.05). PEP/ET는 각 군 사이에 유의한 차이가 없었다. 사지의 수축기, 이완기, 평균 혈압과 PWV는 유의한 양의 상관 관계가 있었다. 사지의 수축기, 이완기, 평균 혈압은 모두 체중, 체질량지수와 유의한 양의 상관 관계가 있었으며 ABI는 체중, 체질량지수 어느 것과도 유의한 상관 관계가 없었다. 결 론 : 본태성 고혈압 청소년에서 정상 청소년에 비해 PWV가 높게 측정되었으므로 예후를 평가하기 위해서 추적 관찰이 필요하다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2935-2940
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• 2007

To diagnose circulatory diseases in the viewpoint of hemodynamics, we need to get quantitative hemodynamic information of blood flows related with the vascular diseases with high spatial resolution of tens micrometer and high temporal resolution in the order of millisecond. For investigating in-vivo hemodynamic phenomena, a new diagnosing technique combining medical radiography and PIV method was newly proposed and developed. This angiographic PIV technique consists of a medical X-ray tube, an X-ray CCD camera, a shutter module for double pulses of X-ray, and a synchronizer. The feasibility of the angiographic PIV technique was tested and quantitative flow velocity field distribution of a flow inside an opaque conduit was acquired by the developed system. It can be used for measuring flow phenomena of nontransparent fluids inside opaque conduits.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 추계학술대회논문집
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• pp.38-43
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• 2009

The objective of this study is to get a fundamental data for the shape of a robot which operates in blood vessels. The overall analysis was calculated with a CFD code. The flow was idealized as a pulsatile flow, and first the robot was assumed as a simple capsule model. Then a drag of the body in the flow was calculated, and this process was repeated, varying the shape. To validate all the result, the pulastile velocity simulation was compared with the theoretical data, and the drag of a body was compared with the existing data of the other papers first. Then with the next calculation the guideline for the design of robot shape was presented.

• Annals of Clinical Neurophysiology
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• 제1권1호
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• pp.39-46
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• 1999

Transcranial doppler ultrasonography (TCD) is a new, non-invasive and easily applicable method to evaluate cerebral hemodynamics. Last 10 years, its use in Korea has been dramatically expanded, but the qualification of TCD laboratory has yet to be settled. Since duplex sonography is seldom used in Korea, we have to depend totally on TCD to evaluate cerebral hemodynamic changes. Thus, all of the available data from every detectabler cerebral arteries has to be obtained for accurate interpretation of TCD measurements. Moreover, flow direction and wave form should be concerned in addition to the flow velocity. In this article, I present technique to measure the anterior, meddle and posterior cerebral arteries, the internal carotid artery siphon and at cervical level, and the vertebral and the basilar artery, and normal values for these measurements which is essential for the adequate interpretation.

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 1994년도 교수 연수회(환경)
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• pp.545-548
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• 1994

Eletrophysiological methods revealed subclinical neuropathy in 26 workers, exposed from 1 to 17 years to lead and whose blood lead (PbB) values had never exceeded $70{\mu}g/100\;ml$, as ascertained by checking the monitor reports of the factory and by careful exposure history. The PbB determinations had been tested repostedly and had been found valid. The main findings were slowing of the maximal motor conduction velocities of the median and ulnar nerves and particularly the conduction velocity of the slower fibers of the ulnar nerve. Eletrophysiological abnormalities comprised fibriliations, diminution of the number of motor units on maximal contraction, and an abnormal. Thus, a dose-response relationship exlets on a group basis. Since the regular monitoring of PbBs in most workers during their entire period of exposure excludes the possibility of a body burden out of proportion to the PbBs silght neuro-logical damage is produced at exposures hitherto regarded as quite sale.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1992년도 학술논문발표회 논문집 제11권 1호
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• pp.103-106
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• 1992

기존의 혈류 속도 측정 방법으로는 인체내에 반사 물질을 투입하는 Fick technique과 electromagnetic flowmeter등을 이용한 invasive method와 Ultrasonic Doppler method에 의한 noninvasive method가 이용되고 있다. 이 방법들은 혈과의 모양이나 혈관에서의 flow velocity profile등에 관한 정확한 정보를 얻을 수 없다. 이와같은 문제점들을 해결하기 위한 혈류속도 측정 방법으로 실험실 조건하에서 인체에서와 유사한 혈류측정 장치를 제작하여, vessel의 표본 체적내의 산란체로부터 후방산란되는 초음파 신호의 correlation을 이용한 Ultrasound Time Domain Correlation (UTDC) technique을 연구하였다. UTDC technique을 이용하여 유속을 측정한 결과, 12% 이하의 정밀도로 평균 유체 유속이 측정되었고, Ultrasonic Doppler method에서 측정할 수 없는 혈과의 모양과 혈관의 각 위치에서의 유속 및 혈관벽에 이물질의 존재여부를 명확히 판단할 수 있었다.

• 한국환경과학회지
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• 제9권5호
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• pp.423-428
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• 2000

The characteristics of Far-infrared rays mineral water(FIR water) have been compared to the tap water by means of relationship between FIR water and Nuclear Magnetic Resonance spectroscopy(NMR), FIR water and thermography FIR water and velocity of blood FIR-water and pH, FIR water and dissolved oxygen(DO), FIR water and Oxidation-Reduction Potential(ORP) using the development FIR water purification of grand prix system. From the experimental result are quite satisfactory when compared with the tap water. Also the FIR water were evaluated to see if those are tasty and healthy using the Hashimoto's Mineral Balance Index. As a result FIR-water was found as tasty and healthy.