Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Microscopic Description of Thermodynamics of Lipid Membrane at
  Liquid-Gel Phase Transition   A microscopic model of the lipid membrane is constructed that provides
analytically tractable description of the physical mechanism of the first order
liquid-gel phase transition. We demonstrate that liquid-gel phase transition is
cooperative effect of the three major interactions: inter-lipid van der Waals
attraction, steric repulsion and hydrophobic tension. The model explicitly
shows that temperature-dependent inter-lipid steric repulsion switches the
system from liquid to gel phase when the temperature decreases. The switching
manifests itself in the increase of lateral compressibility of the lipids as
the temperature decreases, making phase with smaller area more preferable below
the transition temperature. The model gives qualitatively correct picture of
abrupt change at transition temperature of the area per lipid, membrane
thickness and volume per hydrocarbon group in the lipid chains. The calculated
dependence of phase transition temperature on lipid chain length is in
quantitative agreement with experimental data. Steric repulsion between the
lipid molecules is shown to be the only driver of the phase transition, as van
der Waals attraction and hydrophobic tension are weakly temperature dependent.

23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th