• Title/Summary/Keyword: blood velocity

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Structural Analysis for Constructing a Balloon Type Extracoporeal Membrane Oxygenator using CFD Analysis (CFD 해석을 이용한 Balloon형 인공심폐기 설계를 위한 구조적 해석)

  • Park, Young-Ran;Shim, Jeong-Yeon;Kim, Gi-Beum;Kim, Shang-Jin;Kang, Hyung-Sub;Kim, Jin-Shang;Kim, Min-Ho;Hong, Chul-Un;Kim, Seong-Jong
    • Korean Chemical Engineering Research
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    • v.49 no.2
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    • pp.238-243
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    • 2011
  • In this study, we attempted a structural analysis in order to design a balloon type extracorporeal membrane oxygenator that can induce blood flow without using blood pumps for the purpose of complementing the weakness in the existing extracorporeal membrane oxygenator. To analyze the flow characteristic of the blood flow within the virtual model of extracorporeal membrane oxygenator, computational fluid dynamics(CFD) modeling method was used. The operating principle of this system is to make the surface of the extracorporeal membrane oxygenator keep contracting and dilating regularly by applying pressure load using a balloon, and the 'ime Function Value'that changes according to the time was applied by calculating a half cycle of sine waveform and a cycle of sine.waveform Under the assumption that the uni-directional blood flow could be induced if the balloon type extracorporeal membrane oxygenator was designed as per the method described above, we conducted a structural analysis accordingly. We measured and analyzed the velocity and pressure of blood flow at both inlet and outlet of the extracorporeal membrane oxygenator through CFD simulation. As a result of the modeling, it was confirmed that there was a flow in accord with the direction of the blood by the contraction/dilation. With CFD simulation, the characteristics of blood flow can be predicted in advance, so it is judged that this will be able to provide the most optimized design in producing an extracorporeal membrane oxygenator.

The Effect of Low-Intensity Treadmill Exercise on Blood Levels of Glucose, Insulin and Lipids in Streptozotocin-Induced Diabetic Rats (저강도 treadmill 운동이 streptozotocin 유도 당뇨쥐의 혈당, 인슐린 및 지질 농도에 미치는 영향)

  • 김세종;서혜림;고정림;염종우;예정복;이선주;김경환;손원협;장은숙
    • Journal of Life Science
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    • v.14 no.2
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    • pp.245-251
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    • 2004
  • Exercise is beneficial to the diabetic patients and streptozotocin-induced diabetic rat has been used for the study of exercise effect. The purpose of this study was to establish the optimal condition of induction of hyperglycemic diabetic rat using streptozotocin and to examine the preventive effect of treadmill exercise on the diabetic rat before and after streptozotocin injection. Intraperitoneal injection of increasing amount of streptozotocin up to 40 mg/kg dose-responsively induce hyperglycemic diabetic rat and inversely reduced the blood insulin level. Body weight was also gradually reduced with the increasing amount of streptozotocin. Control and diabetic rats exercised for 4 weeks before streptozotocin injection. The exercise was performed in the treadmill for 25 minutes a day and 5 times a week with low intensity (0 degree tilt, 15 m/min velocity). Following streptozotocin injection, the blood glucose level was measured every week and the rat was sacrificed after 4 weeks to measure the concentration of insulin and blood lipids. The blood levels of glucose and insulin was significantly reduced with exercise before streptozotocin injection, while those were not changed after streptozotocin injection. The levels of blood lipids such as total cholesterol, HDL-cholesterol, LDL-cholesterol and triglyceride were close to normal control rats. From this study, researchers found the optimal condition of preparation of streptozotocin-induced hyperglycemic diabetic rat, and the mild treadmill exercise has beneficial effect on preventing hyperglycemia and hyperlipidemia. Thus, even low intensive running prevent not only diabetes but also diabetic vascular complications.

Comparison of Pulsatile and Non-Pulsatile Extracorporeal Circulation on the Pattern of Coronary Artery Blood Flow (체외순환에서 박동 혈류와 비박동 혈류가 관상동맥 혈류양상에 미치는 영향에 대한 비교)

  • Son Ho Sung;Fang Yong Hu;Hwang Znuke;Min Byoung Ju;Cho Jong Ho;Park Sung Min;Lee Sung Ho;Kim Kwang Taik;Sun Kyung
    • Journal of Chest Surgery
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    • v.38 no.2 s.247
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    • pp.101-109
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    • 2005
  • Background: In sudden cardiac arrest, the effective maintenance of coronary artery blood flow is of paramount importance for myocardial preservation as well as cardiac recovery and patient survival. The purpose of this study was to directly compare the effects of pulsatile and non-pulsatile circulation to coronary artery flow and myocardial preservation in cardiac arrest condition. Material and Method: A cardiopulmonary bypass circuit was constructed in a ventricular fibrillation model using fourteen Yorkshire swine weighing $25\~35$ kg each. The animals were randomly assigned to group I (n=7, non-pulsatile centrifugal pump) or group II (n=7, pulsatile T-PLS pump). Extra-corporeal circulation was maintained for two hours at a pump flow of 2 L/min. The left anterior descending coronary artery flow was measured with an ultrasonic coronary artery flow measurement system at baseline (before bypass) and at every 20 minutes after bypass. Serologic parameters were collected simultaneously at baseline, 1 hour, and 2 hours after bypass in the coronary sinus venous blood. The Mann-Whitney U test of STATISTICA 6.0 was used to determine intergroup significances using a p value of < 0.05. Result: The resistance index of the coronary artery was lower in group II and the difference was significant at 40 min, 80 min, 100 min and 120 min (p < 0.05). The mean velocity of the coronary artery was higher in group II throughout the study, and the difference was significant from 20 min after starting the pump (p < 0.05). The coronary artery blood flow was higher in group II throughout the study, and the difference was significant from 40 min to 120 min (p < 0.05) except at 80 min. Serologic parameters showed no differences between the groups at 1 hour and 2 hours after bypass in the coronary sinus blood. Conclusion: In cardiac arrest condition, pulsatile extracorporeal circulation provides more blood flow, higher flow velocity and less resistance to coronary artery than non-pulsatile circulation.

Comparison of Echocardiogram and Clinical Profile between Metabolically Healthy Obese (MHO) and Non Metabolically Healthy Obese (Non-MHO) Subjects

  • Hong, Seung-Bok;Shin, Kyung-A;Choi, Wan-Soo
    • Biomedical Science Letters
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    • v.18 no.3
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    • pp.260-267
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    • 2012
  • Obesity is associated with cardiovascular risk factors, such as dyslipidemia, hypertension and diabetes. However the presence of the obesity related deranged metabolic profiles varies widely among obese individuals. These individuals, known as 'metabolically healthy obese phenotype (MHO)', despite having excessive body fatness, display favorable metabolic profiles characterized by insulin sensitivity, no hypertension, as well as less dyslipidemia, less inflammation. The purpose of this study was to compare cardiac characterization and clinical profile of MHO and Non-MHO (nonmetabolically healthy obese) subjects in men. We measured treadmill exercise capacity (METs) and maximum blood pressure (BP) in 210 subjects through a medical checkup at J General Hospital. Metabolic syndrome was defined according to the modified Adult Treatment Panel III definition criteria. Both MHO and Non-MHO subjects showed statistically significant changes in the left ventricular mass index (P<.001, P<.01, respectively), A-velocity (P<.01, P<.001, respectively), E/A ratio (P<.01, P<.001, respectively), E'-velocity (P<.001, P<.001, respectively), HOMA-IR (P<.01, P<.001, respectively) and maximum systolic BP (P<.01, respectively) compared with the MH-NO (metabolically healthy non obese) subjects. In conclusion, MHO participants were at increased risk of cardiovascular disease and partly metabolic disorder.

A Study on Arterial Characterization using Finger-Toe Index (FTI) (지첨-족지 지수에 의한 동맥 혈관 특성화 연구)

  • Byeon, M.K.;Han, S.W.;Huh, W.
    • Journal of Biomedical Engineering Research
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    • v.28 no.6
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    • pp.777-785
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    • 2007
  • In this paper, Finger-Toe Index (FTI) is proposed as an analytic parameter for the characterization of arterial vessel. Different from the currently being employed pulse wave velocity (PWV) information of the volume pulse wave measured from 4 arterial channels, the proposed FTI uses the ratio of the shorter of the two up-stroke time of PPG from fingers ($UT_{finger}$) and that of PPG (Photoplethysmography) from toes ($UT_{toe}$). To verify the usefulness of the proposed method, Finger-Toe Indexes were derived from the volume pulse waves acquired from 50 people under examination aged from 12 to 81 years old, and they were then compared with blood pressure ankle-brachial index (ABI). It was successfully demonstrated that the arterial stiffness can be estimated with respect to age and FTI is more strongly correlated with the pulse transit time than ABI. From the regression analysis, we also found that FTI has significant correlation PWV for a quantitative index of arterial stiffness and provides more accurate information than ABI for the characterization of arterial vessel.

Review of measurement of prostate specific antigen: in the aspect of insurance medicine (전립선암 선별을 위한 PSA 측정의 보험의학적 의미)

  • Park, Kwang-Il
    • The Journal of the Korean life insurance medical association
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    • v.29 no.1
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    • pp.16-21
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    • 2010
  • The measurement of prostate specific antigen (PSA) in screening for prostate cancer is recently performed as a routine check-up in clinical medicine and insurance medicine. Several factors may affect serum PSA levels. As prostate size increases with increasing age, the PSA concentration also rises. Increasing body mass index (BMI) is associated with a lower mean PSA concentration. Inhibitors of 5-alpha-reductase such as finasteride and dutasteride produce a 50 percent or greater decrease in serum PSA during the first three months of therapy, which persists as long as the drug is continued. Men who are regularly taking non-steroidal antiinflammatory drugs (NSAIDs) or acetaminophen have lower PSA levels. Emerging concepts regarding PSA testing that may help refine the interpretation of an elevated concentration include: PSA density, PSA velocity, and Free versus complexed or bound PSA. With many insurance companies, PSA level has become part of a standard battery of blood tests, along with HIV, cholesterol, liver enzymes, and other predictors of premature death. But, there is no clear proof of benefit, so we have to monitor the value of PSA test as a prostate cancer screening test in insurance medicine.

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Association of Uric Acid Levels with Arterial Stiffness in Korean Women and Non-smoking Men

  • Sull, Jae Woong;Koh, Eun Na;Cho, Sung Kweon;Bae, Hyung-Joon;Jee, Sun Ha
    • Biomedical Science Letters
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    • v.23 no.3
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    • pp.201-207
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    • 2017
  • Measuring the pulse wave velocity (PWV) is a non-invasive method for evaluating the stiffness of the vessel wall. While previous studies investigated the association of uric acid level with arterial stiffness, most did not consider smoking status and obesity as covariates. The objective of this study was to investigate the relationship between uric acid levels and arterial stiffness, considering smoking status and obesity. We studied 3390 subjects (1940 males and 1450 females). Abnormal PWV was also defined as the highest quartile of values in the subjects. Data were analyzed using Pearson correlation, t-test, and multiple regression analysis. Approximately 41.9% of men and 3.7% of women were current smokers. Prevalence of hypertension was 11.4% in men and 7.0% in women. In women, hyperuricemia was associated with abnormal PWV (OR 1.58; 95% CI 1.03~2.43). Hyperuricemia was also associated with abnormal PWV (OR 2.37; 95% CI 1.01~5.59) in non- or light male smokers with normal blood pressure. This study suggests that uric acid is associated with arterial stiffness in women and non-smoking men.

EFFEECTS OF NON-NEWTONIAN FLUID MODEL ON HEMODYNAMICS IN CEREBRAL SACCULAR ANEURYSMS (낭상 뇌동맥류 혈류유동에서 비뉴우토니안 유체 모델의 영향)

  • Park, J.S.;Lee, S.W.
    • Journal of computational fluids engineering
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    • v.16 no.2
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    • pp.81-87
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    • 2011
  • The importance of shear thinning non-Newtonian blood rheology on the hemodynamic characteristics of idealized cerebral saccular aneurysms were investigated by carrying out CFD simulations assuming two different non-Newtonian rheology models (Carreau and Ballyk models). To explore effects of vessel curvature, a straight and a curved vessel geometry were considered. The wall shear stress(WSS), relative residence time(RRT) and velocity distribution were compared at the different phases of cardiac cycle. As expected, blood entered the aneurysm at the distal neck and created large vortex in both aneurysms, but with higher momentum on the curved vessel. Hemodynamic characteristics such as WSS, and RRT exhibited only minor effects by choice of different rheological models although Ballyk model produced relatively higher effects. We conclude that the assumption of Newtonian fluid is reasonable for studies aimed at quantifying the hemodynamic characteristics, in particular, WSS-based parameters, considering the current accuracy level of medical image of cerebral aneurysm.

Multiple Brain Calcification in Chronic Lead Poisoning (만성 연중독자에서의 다발성 뇌석회화 병변)

  • Kim, Sung-Ryul;Kim, Byoung-Gwon;Hong, Young-Seoub;Dam, Do-Won;Choi, Soon-Seob;Jung, Kap-Yull;Kim, Joon-Youn
    • Journal of Preventive Medicine and Public Health
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    • v.28 no.2 s.50
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    • pp.398-405
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    • 1995
  • We experienced a case of occupational lead poisoning employed in a secondary lead smelting plant for 12 years. The patient was 39-year-old male and had been felt dizziness, recent memory impairment and intermittent severe abdominal pain for 2 years. On admission, blood lead level was $92.9{\mu}g/dl$, urinary lead level was $19.9{\mu}g/l$ and zinc protoporphyrin level was $226.0{\mu}g/dl$. On the blood test, hemoglobin was 10.6g/dl and showed normocytic normochromic anemia. There were no abnormal findings in the biochemical and hormonal tests. Decrease of I.Q. and use of words in speaking were found in the psychiatric and psychologic examinations. We observed the finding of motor polyneuropathy in the nerve conduction velocity test. Computed tomographic finding showed calcification lesions in the basal ganglia, dentate nuclei, caudate nuclei, and especially characteristic multiple calcifications were located in the subcortical white matter.

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직물의 자외선 방어율에 따른 인체의 Vit. $D_3$ 합성과 온열생리적인 반응

  • 송명견;안령미;신정화
    • Journal of the Korean Society of Clothing and Textiles
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    • v.23 no.7
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    • pp.980-986
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    • 1999
  • This study was done to ivestigate the fabrics thatminimized harmfulness of UVB(ultraviolet B) and that might product Vit. {{{{ {D }`_{3 } ^{ } }} by UVB. Twelve female subjects wearing in three different types i.e fabric A(UVB 100% protection) fabric B(UVB 50% protection) and bikinii were exposed to outdoor environment (Air Temp : 25℃, 42% R,H Air velocity : 0.13m/s UV does :6KJ/m2) Blood samples were taken 24 hours before the after the experiment in order to examine concentration of vit.{{{{ {D }`_{3 } ^{ } }} in the blood. During the experiment axillary temperature skin temperature of 7 areas(forehead Chest Upper arm, Hand Thigh Lower leg, Foot) were measured. The more irradiated areas by UVB were the more the concentration of serum 25(OH){{{{ {D }`_{3 } ^{ } }} were significantly. Mean skin temperature was significantly low levekl in wearing the fabric of UVB 50% protection (p<0.001) Axillary temperature was significantly high level in wearing the fabric of UVB 50% protection (p<0.001). Therefore the fabric of UVB 50% protection intercepts the radiation and has advantage to give off body heat over other fabrics

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