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Faculty

Michael Harrison, Professor Emeritus

Michael HarrisonE-mail:
Website: www.pa.msu.edu/~harrison/

Education

B.A. 1954 Harvard University
M.S. 1956 University of Chicago
Ph.D. 1960 University of Chicago

 

 

Research Focus

My present work is in biological physics and explores the theoretical physics underlying the role of thermal pressure fluctuations excited within tightly packaged DNA while it is ejected from protein capsid shells that enclose the viral DNA genome. The virus dynamics is discussed in a model calculation. At equilibrium before ejection we assume that the very long DNA molecule is folded many times into a bundle of parallel segments that forms an equilibrium conformation at minimum free energy, which presses tightly against the virus' capsid walls. Using a canonical ensemble at temperature T Kelvin we calculate internal pressure fluctuations against a slowly moving or static capsid mantle for an elastic continuum model of the folded DNA bundle. It is found that fluctuating pressures on the capsid from thermal excitation of longitudinal acoustic vibrations in the bundle whose wavelengths are exceeded by the bend persistence length may have root-mean-square values that are several tens of atmospheres for typically small phage dimensions. Comparisons with data on three mutants of lambda phage with different molecular lengths and genome ejection pressures suggests a multi-stage ejection process.

Recent Publications

Resonant Excitation of Plasmons in Thin Films by Electromagnetic Waves. Phys. Rev. Lett. 21, 85 (1968)

The Cubic Growth of AIDS Cases: General Dependence on Early Infection Rates and Distribution Times to Appearance of Clinical Symptoms. J. Math. Biol. 27, 523 (1989).

Paramagnetic and Heat Capacity Oscillations of Two-Dimensional Electron Gas Systems Confined Within Parabolic Quantum Wells. Phys. Rev.B 48, 5668 (1993)

Possible Giant Orbital Paramagnetism in Nanometer Scale 2DEG Strips. xxx.lanl.gov. arXiv: 0902.0968, March 2009.

Fluctuation Assisted Ejection of DNA From Bacteriophage. xxx.lanl.gov. arXiv: 1009.3473v1, August 2010.