Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Structural Transition of Actin Filament in a Cell-Sized Water Droplet
  with a Phospholipid Membrane   Actin filament, F-actin, is a semiflexible polymer with a negative charge,
and is one of the main constituents on cell membranes. To clarify the effect of
cross-talk between a phospholipid membrane and actin filaments in cells, we
conducted microscopic observations on the structural changes in actin filaments
in a cell-sized (several tens of micrometers in diameter) water droplet coated
with a phospholipid membrane such as phosphatidylserine (PS; negatively-charged
head group) or phosphatidylethanolamine (PE; neutral head group) as a simple
model of a living cell membrane. With PS, actin filaments are distributed
uniformly in the water phase without adsorption onto the membrane surface
between 2 and 6 mM Mg2+, while between 6 and 12 mM Mg2+, actin filaments are
adsorbed onto the inner membrane surface. With PE, actin filaments are
uniformly adsorbed onto the inner membrane surface between 2 and 12 mM Mg2+.
With both PS and PE membranes, at Mg2+ concentrations higher than 12 mM, thick
bundles are formed in the bulk water droplet accompanied by the dissolution of
actin filaments from the membrane surface. The attraction between actin
filaments and membrane is attributable to an increase in the translational
entropy of counterions accompanied by the adsorption of actin filaments onto
the membrane surface. These results suggest that a microscopic water droplet
coated with phospholipid can serve as an easy-to-handle model of cell
membranes.

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The categories of this paper are: patt-sol
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The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
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The categories of this paper are: stat
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The categories of this paper are: cmp-lg
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The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: nlin
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The categories of this paper are: cs
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The categories of this paper are: atom-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: quant-ph