Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nucleosome interactions in chromatin: fiber stiffening and hairpin
  formation   We use Monte Carlo simulations to study attractive and excluded volume
interactions between nucleosome core particles in 30 nm-chromatin fibers. The
nucleosomes are treated as disk-like objects having an excluded volume and
short range attraction modelled by a variant of the Gay-Berne potential. The
nucleosomes are connected via bendable and twistable linker DNA in the crossed
linker fashion. We investigate the influence of the nucleosomal excluded volume
on the stiffness of the fiber. For parameter values that correspond to chicken
erythrocyte chromatin we find that the persistence length is governed to a
large extent by that excluded volume whereas the soft linker backbone
elasticity plays only a minor role. We further find that internucleosomal
attraction can induce the formation of hairpin configurations. Tension-induced
opening of such configurations into straight fibers manifests itself in a
quasi-plateau in the force-extension curve that resembles results from recent
micromanipulation experiments. Such hairpins may play a role in the formation
of higher order structures in chromosomes like chromonema fibers.

3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin