Biomedical subjects

S Panyukov

Publications and source records attributed to S Panyukov.

3 recordsLinked to original sources

PubMed2001

Fluctuating elastic rings: statics and dynamics.

We study the effects of thermal fluctuations on elastic rings. Analytical expressions are derived for correlation functions of Euler angles, mean-square distance between points on the ring contour, radius of gyration, and probability distribution of writhe fluctuations. Since fluctuation amplitudes diverge in the limit of vanishing twist rigidity, twist elasticity is essential for the description of fluctuating rings. We discover a crossover from a small scale regime in which the filament behaves as a straight rod, to a large scale regime in which spontaneous curvature is important and twist rigidity affects the spatial configurations of the ring. The fluctuation-dissipation relation between correlation functions of Euler angles and response functions, is used to study the deformation of the ring by external forces. The effects of inertia and dissipation on the relaxation of temporal correlations of writhe fluctuations, are analyzed using Langevin dynamics.

Algorithms↗

PubMed2000

Thermal fluctuations of elastic filaments with spontaneous curvature and torsion.

We study the effects of thermal fluctuations on thin elastic filaments with spontaneous curvature and torsion. We derive analytical expressions for the orientational correlation functions and for the persistence length of helices and find that this length varies nonmonotonically with the strength of thermal fluctuations. In the weak fluctuation regime, the persistence length of a spontaneously twisted helix has three resonance peaks as a function of the twist rate. In the limit of strong fluctuations, all memory of the helical shape is lost.

Algorithms↗

PubMed2000

Fluctuating filaments: statistical mechanics of helices

We examine the effects of thermal fluctuations on thin elastic filaments with noncircular cross section and arbitrary spontaneous curvature and torsion. Analytical expressions for orientational correlation functions and for the persistence length of helices are derived, and it is found that this length varies nonmonotonically with the strength of thermal fluctuations. In the weak fluctuation regime, the local helical structure is preserved and the statistical properties are dominated by long-wavelength bending and torsion modes. As the amplitude of fluctuations is increased, the helix "melts" and all memory of intrinsic helical structure is lost. Spontaneous twist of the cross section leads to resonant dependence of the persistence length on the twist rate.

Journal Article↗