著者

Keizo WATANABE YANUAR Hiroshi MIZUNUMA

出版者

The Japan Society of Mechanical Engineers

雑誌

JSME International Journal Series B Fluids and Thermal Engineering (ISSN:13408054)

巻号頁・発行日

vol.41, no.3, pp.525-529, 1998-08-15 (Released:2008-02-18)

参考文献数

4

被引用文献数

51 55

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A real fluid does not slip at the surface of a solid boundary. Most experimental results of a Newtonian fluid satisfy with this condition. If a real fluid can slip freely over the surface of a solid boundary, how can we deduce the slip velocity. The purpose of this study is to experimentally clarify fluid slip velocity of Newtonian fluids at the duct wall. Velocity profiles of tap water and 20 wt% glycerin solution flowing in a square duct with a highly water repellent wall were measured by means of a conical hot film anemometer. Consequently, the velocity profile with the slip is measured, and the laminar drag reduction phenomena and the friction factor formula for a square duct with fluid slip at the wall have been obtained.

著者

Sandi SUFIANDI Hiromichi OBARA Huai-Che HSU Shin ENOSAWA Hiroshi MIZUNUMA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

pp.17-00421, (Released:2017-12-04)

参考文献数

34

被引用文献数

1

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Improving the process of cell injection during hepatocyte transplantation requires an understanding of the causal relationships that shear, direct contact cells with a solid surface, and cell deformation have on cell viability loss. A linear shear model was used to model this loss of cell viability during their movement on a solid surface as part of the injection step of hepatocyte transplantation. Rat hepatocytes were studied under linear shear using two parallel plates, with a ”tight” condition that had a 25 μm gap, and a ”loose” gap condition with a > 25 μm gap, to determine the effects of cell deformation, and simulate cell viability loss during injection. Cell morphology and deformation were also observed using time-lapse images. Direct contact with a solid surface is deleterious for cells, and live cells became deformed under shear stress until they lost viability. The cell size could decrease or increase during deformation, and a loss of viability could occur due to a loss of membrane integrity or cell rupture. The space limitations in the tight gap could prevent cell expansion, which delayed the process of cell viability loss. In summary, preventing the direct contact of hepatocytes with a solid surface is recommended to improve the cell injection process during transplantation.

著者

Sandi SUFIANDI Hiromichi OBARA Huai-Che HSU Shin ENOSAWA Naoto MATSUNO Hiroshi MIZUNUMA

出版者

一般社団法人 日本機械学会

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

pp.17-00325, (Released:2017-10-12)

参考文献数

33

被引用文献数

5

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A sufficient number of functional live hepatocytes delivered to a recipient is necessary for cell therapy. Preventing cell viability loss during the cell injection process is important to improve the clinical outcomes of hepatocyte transplantation. The critical location of cell viability loss is important to identify the causal relationship between the viability loss and cell injection process. In this study, the critical location of cell viability loss was determined experimentally in a rectangular microchannel by microscopic high-speed camera observations. Live hepatocyte distributions were investigated upstream and downstream, and measured on three planes, top, center, and bottom, under horizontally or vertically supplied conditions of the syringe orientation. Sedimented and uniform dispersion conditions of the live hepatocyte distribution at upstream of the microchannel were classified according to observations at horizontal and vertical syringe orientations, respectively. Higher hepatocyte viability loss was found under the sedimented condition. The results suggested that the critical location of hepatocyte viability loss was on the bottom plane of the microchannel. Furthermore, physical causes of the hepatocyte viability loss were found by micro-scale observations of the cell velocity and diameter during the cell injection process. This information may contribute to development of a guideline for the cell injection process to improve hepatocyte transplantation.