• Journal of information and communication convergence engineering
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• v.16 no.4
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• pp.258-263
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• 2018

Color Doppler sonography is a useful tool for examining blood flow and related indices. However, it should be done by well-trained operator, that is, operator subjectivity exists. In this paper, we propose an automatic blood flow area extraction method from brachial artery that would be an essential building block of computer aided color Doppler analyzer. Specifically, our concern is to examine hypertension suspicious (prehypertension) patients who might develop their symptoms to established hypertension in the future. The proposed method uses fuzzy C-means clustering as quantization engine with careful seeding of the number of clusters from histogram analysis. The experiment verifies that the proposed method is feasible in that the successful extraction rates are 96% (successful in 48 out of 50 test cases) and demonstrated better performance than K-means based method in specificity and sensitivity analysis but the proposed method should be further refined as the retrospective analysis pointed out.

• Journal of the Korean Society of Visualization
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• v.13 no.2
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• pp.28-32
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• 2015

Blood flow simulations in an realistic carotid bifurcation model with considering wall compliance were carried out to investigate the effect of wall elasticity on the wall shear stress and wall solid stress. Canonical waveforms of flow rates and pressure in carotid arteries were imposed for boundary conditions. Compared to a rigid wall model, we found an increased recirculation region at the carotid bulb and an overall reduction of wall shear stress in a compliant model. Additionally, there was appreciable change of flow rate and pressure wave in longitudinal direction. Both solid and wall shear stress concentration occur at the bifurcation apex.

• Journal of Biomedical Engineering Research
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• v.29 no.5
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• pp.376-383
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• 2008

High-flux dialysis treatment removes various toxins via diffusion as well as convection, which is induced by ultrafiltration and backfiltration. In this study, in vitro (Using the distilled water and the bovine's blood) comparison test was performed to determine whether utilization of a high flux dialyzer paired with different pumps would increase the efficiency of convection. At the same blood flow rates, a pulsatile pump and a roller pump were employed to propel the distilled water and bovine whole blood to a high flux dialyzer. Pressures at the dialyzer inlet and outlet in the blood circuit and in the dialysate circuit were measured, respectively. From these data, we calculated the transmembrane pressure and predicted the ultrafiltration and backfiltration rates developed by both pumps. Using the bovine's blood experiment, ultrafiltration and backfiltration rates were 1.6 times higher with the pulsatile pump than with the roller pump. We conclude that utilization of a pulsatile pump in high flux hemodialysis treatments increases ultrafiltration volume, compared with a roller pump under conditions of the same blood flow rate.

• The Korea Journal of Herbology
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• v.23 no.4
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• pp.71-79
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• 2008

Objectives: SimJeok-Hwan(CP, Cardiotonic Pills) was made to treat patients with coronary arteriosclerosis, angina pectoris and hyperlipidemia. This study was designed to investigate the effects of CP on Proliferation rates neuroglia cells and protective effect of CP against oxidative stress, and also investigate the effects on regional Cerebral Blood Flow(rCBF) in normal rats. Methods: In this experiment, effects of CP on proliferation rates of neuroglia cells were measured using modified MTT methods. Oxidative stress was induced by treatment with 200 mM of hydrogen peroxide for 2 hr. rCBF and MABP were measured using Laser doppler flowmeter. Results: Treatment with CP elevated proliferation rates in C6 cells. In addition, CP protected cell death of C6 cells induced by oxidative stress. In results, rCBF was elevated by treatment with CP in normal rats. But, Mean Arterial Blood Pressure(MABP) did not affected by CP. In addition, the elevation of rCBF was blacked by pre-treatment with 1 mg/kg of indomethacin effectively. On the other hand, pre-treatment with 0.01 mg/kg of methylene blue did not affect rCBF level in normal rats. Conclusions: In conclusion, these results suggest that CP can act as anti-oxidant to protect neuroglia cells and also suggest that CP can elevate rCBF, which are involved in cyclooxygenase pathway.

• International Journal of Fluid Machinery and Systems
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• v.3 no.2
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• pp.102-112
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• 2010

Artificial heart pumps have attracted the attention of researchers around the world as an alternative to the organ used in cardiac transplantation. Conventional centrifugal pumps are no longer considered suitable for long-term application because of the possibility of occurrence of blood leakage and thrombus formation around the shaft seal. To overcome this problem posed by the shaft seal in conventional centrifugal pumps, the magnetically suspended centrifugal pump has been developed; this is a sealless rotor pump, which can provide contact-free rotation of the impeller without leading to material wear. In Europe, clinical trials of this pump have been successfully performed, and these pumps are commercially available. One of the aims of our study is to numerically examine the internal flow and the effect of leakage flow through the gap between the impeller and the pump casing on the performance of the pump. The results show that the pressure head increases compared with the pump without a gap for all flow rates because of the leakage of the fluid through the gap. It was observed that the leakage flow rate in the pump is sufficiently large; further, no stagnant fluid or dead flow regions were observed in the pump. Therefore, the present pump can efficiently enhance the washout effect.

• Proceedings of the KTCVS Conference
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• 1996.10a
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• pp.21-21
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• 1996

• Journal of Biomedical Engineering Research
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• v.28 no.3
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• pp.387-391
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• 2007

An oxygenator is a very important artificial organ and widely used for patients with lung failure or during open heart surgery. Although an oxygenator has been widely studied worldwide to enhance its efficiency, studies on oxygenators, in particular when using a pulsatile blood flow, are domestically limited. Therefore, a new oxygenator was developed in the lab and animal experimental results are described in the paper. The oxygenator is composed of polycarbonate housing and polypropylene hollow fibers. It has a total length of 400 mm and a surface area of $1.7 m^2$. The animal experiment lasted for 4 hours. The blood flow rate was set to 2 L/min and a pulsatile blood pump, T-PLS (Twin-Pulse Life Support), was used. Samples were drawn at the oxygenator's inlet and outlet. The total hemoglobin (Hb), saturation oxygen ($sO_2$), and partial oxygen pressure ($pO_2$), partial $CO_2$ pressure ($pCO_2$), and plasma bicarbonate ion concentration ($HCO_3^-$) were measured. The oxygen and carbon dioxide transfer rates were also calculated based on the experimental data in order to estimate the oxygenator's gas transfer efficiency. The oxygen and carbon dioxide transfer rates were $16.4{\pm}1.58$ and $165.7{\pm}10.96 mL/min$, respectively. The results showed a higher carbon dioxide transfer rate was achieved with the oxygenator. Also, the mean inlet and outlet blood pressures were 162.79 and 137.92 mmHg, respectively. The oxygenator has a low pressure drop between its inlet and outlet. The aim of own preliminary study was to make a new oxygenator and review its performance when applying a pulsatile blood pump thus, confirming the possibility of a new oxygenator suitable for pulsatile flow.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1919-1922
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• 2003

Bypass anastomosis are frequently adopted for surgical treatments. After the bypass grafting, the bypass artery is often occluded due to restenosis and/or anastomotic neointimal fibrous hyperplasia phenomena. Optimal coronary bypass anastomosis should be investigated to improve the patency for the arterial bypass techniques. The objective of this study is to investigate the influence of bypass with sequential bypass effects in the stenosed coronary artery. Numerical analyses are focused on the understanding of the flow patterns for different sequential anastomosis techniques. Blood flow field is treated as two-dimensional incompressible laminar flow. The finite volume method is adopted for discretization of the governing equations. The Carreau model is employed as the constitutive equation for blood. To find the optimal sequential bypass anastomotic configurations, the mass flow rates at the outlet of different models are compared quantitatively.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.3
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• pp.729-733
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• 2004

Jaeum-Dan was reported new anti-aging effect formula previously. We investigated the physiological effects on human skin with Jaeum-Dan essence (JED). We made a skin application product as essence form contained oriental herbs, and measured various physiological effects such as skin moisture contents, red blood cell flow rates, skin surface temperature, corneocyte exfoliation and skin intensity when volunteers(female, n=40) used the application product for 4 weeks. The results were as follows: The skin moisture contents were not only increased in human face skin through using the product, but also red blood cell flow :rates in face skin were increased. After using the essence, the face skin temperature rose and corneocyte exfoliation was decreased. Furthermore the upper dermis intensity of skin in female face was subsequently increased 4 weeks later. The results indicate that the application product containing JED was improved the physiological effects of human facial skin..

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.5
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• pp.650-659
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• 2013

To investigate the effects of facial blood flow rates(FBFR) and facial skin temperature(FST) generated by Gagam-Jawoonaek(GJ) application(appl.) after Miso Facial Rejuvenation Acupuncture(MFRA). Ten people in their twenties to fifties with no skin diseases were recruited. We randomly divided subjects two groups(A, B) and set the GJ appl. site(group A - right side, group B - left side). MFRA was performed on both sides of their face. Immediately after acupuncture treatment(AT treat.), GJ was applied only half of the face. We measured their FBFR using Laser Doppler Perfusion Imaging(LDPI) and FST using Digital Infrared Thermal Imaging(DITI) at pre-AT treat., immediately after AT treat., twenty and sixty minutes after GJ appl.. We analyzed data using Mann-Whitney test and Wilcoxon test(p < 0.05). After MFRA treat., FBFR on both sides increased. Twenty minutes after JW appl., the changes of FBFR on GJ appl. side($122.9{\pm}43.1PU$) were bigger than GJ non-appl. side($80.9{\pm}38.4PU$), a statistically significant decrease. Sixty minutes after application, FBFR on both sides were recovered almost at the same level as that of pre-AT treat. After MFRA treat., FST on both sides increased. Twenty minutes after GJ appl., the changes of FST on GJ appl. side($1.1{\pm}0.6^{\circ}C$) were comparable to that of GJ non-appl. side($1.2{\pm}0.5^{\circ}C$). Sixty minutes after application, FST on both sides were recovered almost at the same level as that of pre-AT treat.. Gagam-Jawoonaek could decrease facial blood flow rates.