Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Field theoretic study of bilayer membrane fusion: I. Hemifusion
  mechanism   Self-consistent field theory is used to determine structural and energetic
properties of metastable intermediates and unstable transition states involved
in the standard stalk mechanism of bilayer membrane fusion. A microscopic model
of flexible amphiphilic chains dissolved in hydrophilic solvent is employed to
describe these self-assembled structures. We find that the barrier to formation
of the initial stalk is much smaller than previously estimated by
phenomenological theories. Therefore its creation it is not the rate limiting
process. The barrier which is relevant is associated with the rather limited
radial expansion of the stalk into a hemifusion diaphragm. It is strongly
affected by the architecture of the amphiphile, decreasing as the effective
spontaneous curvature of the amphiphile is made more negative. It is also
reduced when the tension is increased. At high tension the fusion pore, created
when a hole forms in the hemifusion diaphragm, expands without bound. At very
low membrane tension, small fusion pores can be trapped in a flickering
metastable state. Successful fusion is severely limited by the architecture of
the lipids. If the effective spontaneous curvature is not sufficiently
negative, fusion does not occur because metastable stalks, whose existence is a
seemingly necessary prerequisite, do not form at all. However if the
spontaneous curvature is too negative, stalks are so stable that fusion does
not occur because the system is unstable either to a phase of stable radial
stalks, or to an inverted-hexagonal phase induced by stable linear stalks. Our
results on the architecture and tension needed for successful fusion are
summarized in a phase diagram.

29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom