Pulling the knot tight
Article Abstract:
The ideal configuration of a knot in a piece of string is similar to equilibrium configurations of knotted DNA molecules. DNA chains are pulled tight and convoluted configurations are not preferred. Two ideal configuration's characteristics of physical importance are writhe and crossing number. Equilibrium configurations of knotted DNA chains show the mean writhe to be nearly equal to, and the mean average crossing number to be linearly associated with that of the ideal configuration. The DNA chain apparently seeks to achieve a minimum energy state.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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High-pressure viscosity of glycerol measured by centrifugal-force viscometry
Article Abstract:
The effect of pressure on the viscosity of glycerol near its glass transition temperature was studied using centrifugal-force viscometry in a diamond-anvil cell. Free-volume theory is a viscosity model that assigns incompressible volumes to molecules. The data show that the model provides accurate predictions of glycerol viscosity for a wide range of pressures. This allows the prediction of pressure effects on the glass transition temperature and structural integrity of the resulting glass.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1993
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Euler's disk and its finite-time singularity
Article Abstract:
Viscous dissipation in the thin layer of air between a circular disk being spun on a table and the table itself is sufficient to explain the abruptness of the settling process. During this process, angular velocity increases without limit.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2000
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