• 한국전산유체공학회:학술대회논문집
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• 1999.11a
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• pp.152-157
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• 1999

For the simulation of the blood flow in coronary artery, the system modeling of coronary hemodynamics is combined with CFD technique. The blood flow in coronary artery interacts with the global coronary circulation. Especially in case of the coronary artery with stenosis, the interaction plays an important role in the hemodynamics of the circulation. In this study we present a combined numerical approach using both the CFD technique for flow simulation and the global system model of coronary circulation. We use a lumped parameter model for the global simulation of coronary circulation whereas the finite element method is employed to compute the viscous flow field in stenosed coronary artery, The time variation of the pressure drop due to stenosis is obtained from the proposed numerical method. Numerical results shows that the flow resistance and pressure drop due to stenosis has a relatively large value in systole.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1679-1682
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• 2008

Pulsatile Extracorporeal Membrane Oxygenation(ECMO) can mitigate the heart load and raise the patient's blood perfusion. But If the ECMO pulsate the blood flow during the systolic period, It can burden to the patient's heart. To avoid the heart injury, we have to consider the relation between output of ECMO, hemodynamic states and heart movement. To raise the efficacy of the pulsatile ECMO, we investigated the coronary perfusion, cardiac muscle tension and hemodynamic states during the ECMO perfusion by using the mathematical model of human blood circulatory system and ECMO. The outflow data of the pulsatile ECMO(T-PLS, Bioheartkorea, Korea) was obtained in vitro experiments. According to the phase and pumping rate of the ECMO, the heart's load and coronary perfusion could be adjusted to the proper levels. The results of the human- ECMO lumped parameter model showed that the synchronizing operation of the pulsatile ECLS can be helpful at stabilizing the patient's hemodynamic states.

• The Korean Journal of Nuclear Medicine
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• v.39 no.2
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• pp.118-123
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• 2005

Positron emission tomography (PET) serves as a gold standard for noninvasive in vivo measurement of myocardial blood flow (MBF) and coronary flow reserve (CFR). CFR can be defined as the ratio of maximally vasodilated MBF over its basal flow. It is an important parameter for the evaluation of functional severity of coronary stenosis and prognositification in various diseases such as dilated cardiomyopathy. $^{13}NH_3,\;H_2^{15}O,\;^{82}Rb$ are widely used radiopharmaceuticals for measuring MBF and CFR, This review introduces imaging techniques and its clinical utility. Cardiac application or PET and PET/CT is expected to be increased in near future.

• Korean Journal of Clinical Pharmacy
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• v.10 no.1
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• pp.19-24
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• 2000

The effect of cimetidine on the pbarmacokinetic parameters of cyclosporine (intravenous administration) were determined in 6 healthy volunteers (22-48 years old, 48-62 kg) by cross-over design. Cyclosporine and cyclosporine metabolites in whole blood were analysed by fluororescence polarization immunoassay (TDx-FLX). The blood concentrations of cyclosporine After pretreatment with cimetidine (200 mg bid, for 3days) were increased significantly at 8-12 hrs compared to the control (p<0.05). The ratios of blood concentrations of cyclosporine metabolites (M1, M17) to parent drug were decreased significantly at 8-12 hrs (p<0.05). Total body clearance (CL) was also decreased significantly (p<0.05), and area under the curve $(AUC,\%)$ was increased but not significant.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.148-148
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• 2003

The cynomolgus monkey(Macaca fascicularis) is used widely in efficacy and safety assessment of new drugs. The ranges of physiological variables are important end points in the toxicological study. Both the basic physiological variables such as body weight, body temperature, blood pressure, urine pH and blood variables such as biochemical and hematological variables were determined in nineteen male and sixteen female monkey prior to treatment.(omitted)

• Korean Journal of Veterinary Research
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• v.42 no.2
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• pp.283-288
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• 2002

The present study was carried out to examine the effect of insulin formula on blood glucose change in normal Sprague-Dawley male rats. Also, this study was performed to investigate the feasibility of oral insulin formula development. To administrate the insulin formula into intestine, the surgical technique, celiotomy, was performed in rats. Insulin formula was administrated at a dose of 24.5 IU/kg via duodenum, ileum, and colon of the rats, and the blood glucose level was measured. For the comparison, the vehicle without insulin was administrated into ileum via celiotomy. Also, this insulin formula was administrated into rats orally using sonde and the same parameter was treasured. The bloods of all groups were collected from tail veins using syringes at given time interval. Orally administrated group did not show the change of blood glucose level and control group slightly show the change of blood glucose level at 1 hour after celiotomy. All intestinally administrated groups showed the change of blood glucose level. Among the tested groups, ileac administration group and colonic administration group showed the significant change of blood glucose level. Particularly, ileac administration group showed the lowest blood glucose level. To calculate the bioavailability of intestinal and oral administration, insulin solution was injected subcutaneosly, common insulin injection route, into another normal rats. The bioavailability of ileac group was 8.3% when compared with subcutaneous injection, duodenal group was 1.8%, colonic group was 4.2%, and oral group was 0.2%, respectively.

• Journal of Biomedical Engineering Research
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• v.41 no.5
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• pp.179-184
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• 2020

Purpose: The purpose of this study was to evaluate the effect according to the NEX, VENC, targeted cardiac phases on the velocity measurement of 4D phase-contrast MRI. Materials and Methods: The abdominal aortic phantom was made to experiment. The working fluid was mixed with water and glycerin to mimic the density and viscosity of human blood. The inlet velocity was Reynolds number 2000. The experimental conditions were NEX 1 and 4, VENC 102 cm/s and 200 cm/s, and 10 and 15 targeted cardiac phases, respectively. The average flow rate, average velocity, maximum velocity, and cross-section area were measured. Results: As a result of the case-by-case comparison, the error rate was less than 5%. There was no significant difference (p > 0.05). Conclusion: It is expected that this result will be useful for acquiring blood flow information in clinical practice.

• Journal of Sensor Science and Technology
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• v.20 no.5
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• pp.343-350
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• 2011

The compliance and stiffness of artery are closely related with disease of arteries. Pulse wave velocity(PWV) in the blood vessel is a basic and common parameter in the hemodynamics of blood pressure and blood flow wave traveling in arteries because the PWV is affected directly by the conditions of blood vessels. However, there is no standardized method to measure the PWV and it is difficult to measure. The conventional PWV measurement has being done by manual calculation of the pulse wave transmission time between coronary arterial proximal and distal points on a strip chart on which the pulse wave and ECG signal are recorded. In this study, a pressure sensor consisting of strain gauges is used to measure the blood pressure of arteries in invasive method and regular ECG electrodes are used to record the ECG signal. The R-peak point of ECG is extracted by using a reference level and time windowing technique and the ascending starting point of blood pressure is determined by using differentiation of the blood pressure signal and time windowing technique. The algorithm proposed in this study, which can measure PWV automatically, shows robust and good results in the extraction of feature points and calculation of PWV.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.2
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• pp.51-56
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• 2021

The brachial systolic blood pressure and pulse pressure are the predictors of cardiovascular disease in individuals over 50 years of age. As the stiffness increases, the reflex amplitude and pressure in the late systole increase, resulting in an increase in left ventricular load and myocardial oxygen demand. Therefore, it is necessary to study how stiffness affects blood pressure. In this study, the blood pressure pulse waves were measured before and after taking the drug, and the blood pressure pulse wave was measured before and after myocardial heart transplantation in patients with heart failure. The correlation between R, L, and C components of the Windkessel model was estimated by increasing blood pressure. As a result of modeling the parameters of the Windkessel model using the curve fitting method, the increase in blood pressure and decrease in systolic rise time were due to the increase in the L component in the RLC Windkessel model. Among the various mechanical characteristics of blood vessels, the most important parameter affecting high BP waveform is the inertance.

• Journal of Veterinary Science
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• v.23 no.4
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• pp.60.1-60.6
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• 2022

Background: A definite diagnosis should be made in the bovine practice field, however, it was difficult to perform laboratory analysis immediately. Currently, three types of portable blood gas analyzers are available in Korea. Objectives: This study aimed to evaluate the correlations among these three analyzers. Methods: Seventy-two plasma samples from Holstein-Friesian cows were used for blood gas analysis, and three instruments (EDAN i15 Vet, VETSCAN i-STAT, and EPOC) were operated simultaneously. Moreover, plasma calcium levels were compared between these portable analyzers and blood chemistry device, which is usually used in a laboratory environment. Pearson analysis was performed to confirm the correlation of each parameter produced with the three instruments and blood chemistry analyzer. Results: As results, high correlation was observed in parameters of pH, pO₂, potassium ion, ionized calcium, and glucose (p < 0.001, r > 0.7). In addition, pCO₂ showed a moderate correlation among the three analyzers (p < 0.001, r > 0.5), and there was no correlation among all instruments for sodium ions. There was also a high correlation between ionized calcium from the three portable devices and total calcium from the biochemistry analyzer (p < 0.001, r > 0.9). Conclusions: In conclusion, there was a high correlation between results from the three different blood gas analyzers used in the bovine clinical field in Korea. Thus, a consistent diagnosis can be made even with different equipment if the operator is aware of the strengths and weaknesses of each piece of equipment and operates it properly.