| Project/Area Number |
10044180
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biomedical engineering/Biological material science
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| Research Institution | Waseda University |
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Principal Investigator |
UMEZU Mitsuo Waseda University, School of Science and Engineering, Professor, 理工学部, 教授 (90132927)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIMOTO Tetsuo Waseda University, Advanced Research Inst for Sci.and Eng.Assoc.Professor, 理工学総合研究センター, 助教授 (50267473)
ANTAKI James ピッツバーグ大学, 医学部, 講師
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1999: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1998: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | hemolysis / shear stress / in vitro test / numerical model / plasma free hemoglobin / energy dissipation / Reyrolds stress / flow visualization |
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| Research Abstract |
Shear stress, which is a tensor value, is regarded as an essential factors of hemolysis, but hemolysis level is a scalar value. Therefore. the authors proposed energy dissipation rate E (J/m^3) as a generalized substitute for shear stress and have formulated the following expression for plasma free hemoglobin.
H=kE^αt (where, k and α are constant values, H : hemoglobin level)
In addition, the difference in the threshold shear level due to the type of stress, namely viscous and Reynolds stress, is believed to be related only to the exposure time. Therefore, preliminary in vitro hemolysis test has been performed using to clarify the effects of laminar and turbulent flows on hemolysis.
In the present experiments, two types of suspension media with different viscosities were used to examine a sufficiently wide range of Reynolds numbers without altering hematocrit or exposure time. Bovine red blood cells were suspended in saline for turbulent flow condition and in dextran solution for laminar flow condition. The viscosity of the suspensions were 1.56cP and 5.20cP, respectively. Blood was circulated for 90 min under the shear stress of 100-500 Pa.
Blasius friction factor was calculated to verify flow condition as a laminar or turbulent. The experimental results exhibited that hemolysis rate under turbulent flow was four times higher than that under laminar flow, suggesting that the effect of viscous and Reynolds stress on hemolysis is not always equal. Then, it became possible to consider that energy dissipation took an important role to predict a level of hemolysis.
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