Shlomi Medalion

Coupling of twist and writhe in short DNA loops.

While bending and twist can be treated as independent degrees of freedom for linear DNA molecules, the loop closure constraint introduces a coupling between these variables in circular DNA. We performed Monte Carlo simulations of wormlike rods with both bending and twist rigidity in order to study the coupling between the writhe and twist distributions for various DNA lengths. We find that for sufficiently short DNA, the writhe distribution differs from that of a model with bending energy only. We show that the factorization approximation introduced by previous researchers coincides, within numerical accuracy, with our simulation results, and conclude that the closure constraint is fully accounted for by the White-Fuller relation. Experimental tests of our results for short DNA plasmids are proposed.

The Distribution of the Area Under a Bessel Excursion and its Moments

A Bessel excursion is a Bessel process that begins at the origin and first returns there at some given time

Effect of Spontaneous Twist on DNA Minicircles

T

Protonation-induced transitions in a DNA brush

T. We study the distribution of the area under such an excursion, which recently found application in the context of laser cooling. The area

Effect of knots on binding of intercalators to DNA.

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Force-free measurements of the conformations of DNA molecules tethered to a wall

A scales with the time as