Influences of biological structural features on the acoustic nonlinearity parameter B/A
Zhang, Jian
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Permalink
https://hdl.handle.net/2142/20285
Description
Title
Influences of biological structural features on the acoustic nonlinearity parameter B/A
Author(s)
Zhang, Jian
Issue Date
1990
Doctoral Committee Chair(s)
Dunn, Floyd
Department of Study
Electrical and Computer Engineering
Discipline
Electrical Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Engineering, Biomedical
Biophysics, Medical
Language
eng
Abstract
The influences of structural factors of biological media on the acoustic nonlinearity parameter B/A were studied at tissue, cellular and molecular levels, using both the thermodynamic method and the finite amplitude method. Experiments were designed to measure the B/A changes by altering structural factors of media physically and biochemically, while keeping chemical compositions unchanged. Evidences were found to support significant structural dependences of the B/A at all three levels. Further analysis suggests that about 26% of dry weight contribution to the total B/A, the B/A value with water contribution subtracted, is due to cell-cell adhesive force in liver tissues, 20% to the hepatocyte cellular structure, and 15% to the molecular structure of protein. No significant B/A changes were observed between the in vivo and in vitro B/A values in cat livers and during the digestion of protein. In addition, it is found that B/A exhibits an unusually large value near the phase transition regions of liposomes, suggesting the effect of relaxational processes on the B/A value. Finally, implications of the above findings are discussed in the light of the previous studies on the compositional dependence of B/A, and a possible rationale by which the B/A depends on both the chemical composition and structural factors is suggested.
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