Analysis of Pulse Heating on a Fluid-Cooled Surface for Fluid Shear Stress

2002 ◽  
Author(s):  
Kevin D. Cole
Keyword(s):  
Heat Transfer ◽  
Shear Stress ◽  
Fluid Shear Stress ◽  
Pulse Heating ◽  
Stress Measurement ◽  
Sensitivity Study ◽  
Transfer Model ◽  
Fluid Shear ◽  
Conduction Model ◽  
Rapid Temperature

This paper is a report of an improved heat transfer model for rapid temperature variations caused by pulse heating of fluid-cooled surfaces, with application to fluid shear-stress measurement. The key improvement is the use of a fully-transient treatment of the heat transfer in the fluid flow as part of a combined convection-conduction model. Surface-temperature results are presented for several fluid/solid combinations for a two-dimensional heater located on the fluid-solid interface. A sensitivity study suggests that pulse heating may be better than steady heating for measurement of fluid shear stress, and that measurements downstream of the heater may also be important.

scholarly journals Epigenetic Changes During Mechanically Induced Osteogenic Lineage Commitment

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Julia C. Chen ◽  
Mardonn Chua ◽  
Raymond B. Bellon ◽  
Christopher R. Jacobs
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Shear Stress ◽  
Fluid Shear Stress ◽  
Methylation Status ◽  
Lineage Commitment ◽  
Fluid Shear ◽  
Osteogenic Lineage ◽  
Osteogenic Markers ◽  
Heterochromatin Structure

Osteogenic lineage commitment is often evaluated by analyzing gene expression. However, many genes are transiently expressed during differentiation. The availability of genes for expression is influenced by epigenetic state, which affects the heterochromatin structure. DNA methylation, a form of epigenetic regulation, is stable and heritable. Therefore, analyzing methylation status may be less temporally dependent and more informative for evaluating lineage commitment. Here we analyzed the effect of mechanical stimulation on osteogenic differentiation by applying fluid shear stress for 24 hr to osteocytes and then applying the osteocyte-conditioned medium (CM) to progenitor cells. We analyzed gene expression and changes in DNA methylation after 24 hr of exposure to the CM using quantitative real-time polymerase chain reaction and bisulfite sequencing. With fluid shear stress stimulation, methylation decreased for both adipogenic and osteogenic markers, which typically increases availability of genes for expression. After only 24 hr of exposure to CM, we also observed increases in expression of later osteogenic markers that are typically observed to increase after seven days or more with biochemical induction. However, we observed a decrease or no change in early osteogenic markers and decreases in adipogenic gene expression. Treatment of a demethylating agent produced an increase in all genes. The results indicate that fluid shear stress stimulation rapidly promotes the availability of genes for expression, but also specifically increases gene expression of later osteogenic markers.

Patterns of fluid shear stress determine atherosclerotic lesion size and vulnerability

2006 ◽  
Vol 45 (3) ◽  
pp. e51
Author(s):  
Caroline Cheng ◽  
Dennie Tempel ◽  
Luc van Damme ◽  
Rien van Haperen ◽  
Rob Krams ◽  
...  
Keyword(s):  
Shear Stress ◽  
Fluid Shear Stress ◽  
Atherosclerotic Lesion ◽  
Lesion Size ◽  
Fluid Shear

The rate of fluid shear stress is a potent regulator for the differentiation of mesenchymal stem cells

2019 ◽  
Vol 234 (9) ◽  
pp. 16312-16319 ◽  
Author(s):  
Danyang Yue ◽  
Mengxue Zhang ◽  
Juan Lu ◽  
Jin Zhou ◽  
Yuying Bai ◽  
...  
Keyword(s):  
Stem Cells ◽  
Shear Stress ◽  
Mesenchymal Stem Cells ◽  
Fluid Shear Stress ◽  
Fluid Shear

scholarly journals Fluid shear stress induces osteoblast differentiation and arrests the cell cycle at the G0 phase via the ERK1/2 pathway

2017 ◽  
Vol 16 (6) ◽  
pp. 8699-8708 ◽  
Author(s):  
Liyin Yu ◽  
Xingfeng Ma ◽  
Junqin Sun ◽  
Jie Tong ◽  
Liang Shi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Shear Stress ◽  
Osteoblast Differentiation ◽  
Fluid Shear Stress ◽  
Fluid Shear ◽  
G0 Phase

scholarly journals TAZ responds to fluid shear stress to regulate the cell cycle

Cell Cycle ◽  
2018 ◽  
Vol 17 (2) ◽  
pp. 147-153 ◽  
Author(s):  
Hyun Jung Lee ◽  
Adesuwa Ewere ◽  
Miguel F. Diaz ◽  
Pamela L. Wenzel
Keyword(s):  
Cell Cycle ◽  
Shear Stress ◽  
Fluid Shear Stress ◽  
Fluid Shear

scholarly journals Turbulent fluid shear stress induces vascular endothelial cell turnover in vitro.

1986 ◽  
Vol 83 (7) ◽  
pp. 2114-2117 ◽  
Author(s):  
P. F. Davies ◽  
A. Remuzzi ◽  
E. J. Gordon ◽  
C. F. Dewey ◽  
M. A. Gimbrone
Keyword(s):  
Shear Stress ◽  
Endothelial Cell ◽  
Fluid Shear Stress ◽  
Vascular Endothelial Cell ◽  
Vascular Endothelial ◽  
Cell Turnover ◽  
Fluid Shear ◽  
Turbulent Fluid
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