• Current Optics and Photonics
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• 제3권1호
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• pp.46-53
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• 2019

Monte Carlo simulations were performed for a three-dimensional tissue model with and without an embedded large vessel, to understand how varying vessel geometry affects surface light distribution. Vessel radius was varied from 1 to 5 mm, and vessel depth from 2 to 10 mm. A larger difference in surface fluence rate was observed when the vessel's radius increased. For vessel depth, the largest difference was seen at a depth of approximately 4 mm, corresponding to human wrist region. When the vessel was placed at depths greater than 8 mm, very little difference was observed. We also tested the feasibility of using two source-detector pairs, comprising two detectors distinctly spaced from a common source, to noninvasively measure blood-scattering changes in a large vessel. High sensitivity to blood-scattering changes was achieved by placing the near detector closer to the source and moving the far detector away from the source. However, at longer distances, increasing noise levels limited the sensitivity of the two-detector approach. Our results indicate that the approach using two source-detector pairs may have potential for quantitative measurement of scattering changes in the blood while targeting large vessels near the human wrist region.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.959-963
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• 2006

A three-dimensional elastic blood vessel model with internal diameter variation is considered to investigate internal flow characteristics and effects of structural deformation. Also, computational analyses for both the rigid model and the fully-coupled FSI model have been conducted in order to compare the shear stress, pressure distribution, and flow velocity in detail. A 70% narrowing area of asymmetric blood vessel model was especially investigated to show the versatility of fluid-structure interaction phenomenon. The results reveal that effect of fluid-structure interaction is very important to accurately investigate the flow characteristics of the blood vessel.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1484-1486
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• 2008

Characteristics of pulsatile flow in 3-dimensional elastic vessel wall should be investigated in order to understand the physiological blood flow in human body. In this study, the modelling of the physiological blood flow in the elastic blood vessel is proposed. Variation of the pressure and the velocity wavefroms are obtained using the FSI method

• 대한한의학원전학회지
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• 제22권4호
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• pp.217-220
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• 2009

In "Hwangjenaegyeong(黃帝內經)", the name of blood vessels is closely related to images of the river, and the word for blood vessel contains the following meaning, such as blood vessel, blood wind as well as blood stasis and so on. In a physiological perspective, the unobstructed blood vessel and normal operation blood are important symbols of health, for blood is the basis for human survival, physical activity and mental activity. In pathology, the external cold, excessive seven emotions and a biased diet can cause many kinds of abnormalities of the blood vessels, which can in turn become causes for a variety of diseases. The theory of blood vessels in "Hwangjenaegyeong" can provide guidance for diagnosis and treatment of cardiovascular diseases in practice.

• 대한기계학회논문집B
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• 제30권4호
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• pp.314-319
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• 2006

To analyze in-vivo blood flow characteristics in a chicken embryo, in-vivo experiment was carried out using micro-PIV technique. Because endothelial cells in blood vessels are subject to shear stress of blood flow, it is important to get velocity field information of the placental blood flow. Instantaneous velocity fields of an extraembryonic blood vessel using a high-speed camera and intravital microscope. The flow images of RBCs were obtained with a spatial resolution of $20\times20{\mu}m$ in the whole blood vessels. The mean velocity field data confirm that the blood flow does show non-Newtonian fluid characteristic. The blood in a branched vessel merged smoothly without any flow separation into the main blood vessel with the presence of a slight bump. This in-vivo micro-PIV measurement technique can be used as a powerful tool in various blood flow researches.

• 대한한방내과학회지
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• 제22권2호
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• pp.119-125
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• 2001

Objectives : This study was conducted to evaluate the effect and mechanism of Geupoongjibo-dan's relaxation of the tension of the blood vessel caused by Phenylephrine and KCI. Methods : In order to study the effect of Geupoongjibo-dan's relaxation of the blood vessel tension, Geupoongjibo-dan extract was infused into Phenylephrine and KCI-induced contracted rabbit aorta strips. To analyze the mechanism of Geupoongjibo-dan's effect on the blood vessel, Geupoongjibo-dan extract infused into Phenylephrine and KCI-induced contracted strips induced by agonists after treatment of N${\omega}$-nitro-L-arginine, Methylene Blue. Results : 1. Geupoongjibo-dan was very effective in relaxing the blood vessels contracted by Phenylephrine. 2. Geupoongjibo-dan was effective against Phenylephrine, than against KCI. 3. Geupoongjibo-dan's more relaxation effect on a blood vessel was terminated by N${\omega}$-nitro-L-arginine and methylene treatment. Conclusion : THis study showed that Geupoongjibo-dan's relaxation effect on a blood vessel is irrelevant to ${\alpha}$-adrenalin receptor, and it relaxes contracted vessels through cGMP channel.

• 대한기계학회논문집B
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• 제29권1호
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• pp.63-70
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• 2005

The main objective of the present study is to predict characteristics of three dimensional pulstitile flow by location of stenosis in blood vessel with the second order bifurcation. The present study simulates the incompressible non-Newtonian laminar blood flows using a Fluent V. 6.0. The Carreau model is employed as the constitutive equation for blood. The numerical simulation carried out at five cases without and with symmetry or asymmetry stenosis. It is found that the no stenosis and stenosis before first bifurcation do not have influence on flow at second bifurcated blood vessel. However, the stenosis after first biburcation has effect on flow at second bifurcated blood vessel.

• Macromolecular Research
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• 제16권4호
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• pp.345-352
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• 2008

Poly(lactic-co-glycolic acid) (PLGA) tubes (5 mm in diameter) were fabricated using an electro spinning method and used as a scaffold for artificial blood vessels through the hybridization of smooth muscle cells (SMCs) and endothelial cells (ECs) differentiated from canine bone marrow under previously reported conditions. The potential clinical applications of these artificial blood vessels were investigated using a canine model. From the results, the tubular-type PLGA scaffolds for artificial blood vessels showed good mechanical strength, and the dual-layered blood vessels showed acceptable hybridization behavior with ECs and SMCs. The artificial blood vessels were implanted and substituted for an artery in an adult dog over a 3-week period. The hybridized blood vessels showed neointimal formation with good patency. However, the control vessel (unhybridized vessel) was occluded during the early stages of implantation. These results suggest a shortcut for the development of small diameter, tubular-type, nanofiber blood vessels using a biodegradable material (PLGA).

• 대한중풍순환신경학회지
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• 제6권1호
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• pp.45-53
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• 2005

Objective : This study was performed to examine the relationship between cerebral blood vessel with meridian by using Transcranial Doppler Ultrasonography(TCD) Method : Monitoring of TCD was examined in 10 healthy people in their twenties (mean age was 26.5±1.00). Each examination was performed before & after acupuncture. Three Meridian were tested. Those were Stomach Meridian, Bladder Meridian & Gallbladder Meridian. Maximum velocity and Mean velocity were analyzed from TCD on different vessel. Result : The results showed significant(p<0.05; Wilcoxon signed rank test) change in some cerebral blood flow after acupuncture. Conclusion : There was the relationship between Meridian and cerebral blood vessel.

• 혜화의학회지
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• 제15권2호
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• pp.263-272
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• 2006

Purpose Brain vessles have autoregulation function, so even when perfusion pressure drops, cerebral blood flow remain stable by vasodilation. Latest research on this reserve of cerebral vessels is being done using TCD, which measures the reserve of the vessels. We did a research comparing cerebral vessel and peripheral vessel reserve between Taeumin, who are more likely to suffer CVA, and the normal. We observed blood flow of Internal carotid artery siphon and radial indicis artery of the two group with TCD. Method We picked 20 people out of patients diagnosed as cerebral infarction at Cheon-An Oriental hospital of Daejeon University. They were diagnosed as Taeumin with QSCCII questionnaire and constitutional differentiation. Using TCD, we measured highest blood flow rate, mean blood flow and asymmetric counting blood flow of Internal carotid artery siphon and radial indicis artery at rest. And then we measured again after stimulating cerebral vessels, by triggering hypercapnia by self apnea and peripheral vessels by palm heating. Result At rest, mean blood flow rate of Internal carotid artery siphon showed significant decrease compared to control group. Blood flow rate of Internal carotid artery siphon after hypercapnia showed significant decline in highest blood flow rate and mean blood flow compared to control group. Cerebral vessel reaction after the hypercapnia induction showed great change in experiment group than the control group. Peripheral vessel reaction after palm heating showed significant decline in experiment group compared to control group. Conclusion In conclusion, measuring the alteration of blood flow used in diagnosing cerebral infarction, is more sensitive when vessel stimulation is done. Non-invasive TCD is effective especially in case of Taeumin who are more likely to suffer vascular disorder than others.