Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The percolation transition of hydration water: from planar hydrophilic
  surfaces to proteins   The formation of a spanning hydrogen-bonded network of hydration water is
found to occur via a 2D percolation transition in various systems: smooth
hydrophilic surfaces, the surface of a single protein molecule, protein powder
and diluted peptide solution. The average number of water-water hydrogen bonds
nH at the percolation threshold varies from 2.0 to 2.3, depending on
temperature, system size and surface properties. Calculation of nH allows an
easy estimation of the percolation threshold of hydration water in various
systems, including biomolecules.

36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
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The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
14
The categories of this paper are: math-ph