Twist dynamics of semiflexible polymer

A number of strange results have been reported for the twist elasticity of a semiflexible filament, actin. In particular dynamic and static methods for determining the torsional twist modulus give very different results. I show here that internal losses (friction) in a semiflexible filament could be an important cause of dissipation and that the interpretation of dynamic experiments should be made in terms of a storage and loss modulus for actin proteins.