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MAE SEMINAR SERIES

Physical Activity and Bone Density in Women and
Evaluation of Parameters Affecting Bovine Blood Hemolysis Testing

Dr. Susan Bowley, PhD
Food and Drug Administration
Friday, December 2, 2005, 1pm
Tompkins Hall of Engineering, 725 23rd Street NW, #204

This talk will provide an overview of two research projects.  The ultimate goal of the first project was to determine a stress exponent relating GRFz history to Calcaneal Bone Mineral Density (CBMD).  A mathematical model of bone density regulation as a function of the daily tissue “effective” stress was previously derived by Dr. Robert Whalen.  Using this model, the influence of daily activity in the form of a daily loading history has been related to bone density of the calcaneus.  The theory incorporates a stress exponent m to account for differences in the importance of magnitude and number of load cycles experienced during daily activity.  The focus of the second research project was the evaluation of red blood cell damage caused by cardiovascular medical devices.  Evaluation of blood damage caused by medical devices is a critical parameter needed to determine the safety of medical devices submitted to the FDA for approval.  Determination of red blood cell damage, or hemolysis, is done by measurement of the amount of hemoglobin released from red blood cells into the plasma, or plasma free hemoglobin (PFHg, mg/dL).  The goals for this work were to 1) evaluate the variability of bovine blood fragility by mechanical testing, 2) evaluate how well a bench-top hemolysis test might be used to predict pump flow hemolysis and 3) evaluate the usefulness of a historical equation used for normalizing blood damage level (the Normalized Index of Hemolysis, NIH).

Dr. Susan Bowley is currently a Postdoctoral Fellow and scientific reviewer at FDA. She obtained a BS in Mechanical Engineering from University of Connecticut in 1988, a MS in Mechanical Engineering from Stanford University in 1992 and a PhD in Biomedical Engineering from University of Virginia in 2000.