Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Balance of enthalpy and entropy in depletion forces   Solutes added to solutions often dramatically impact molecular processes
ranging from the suspension or precipitation of colloids to biomolecular
associations and protein folding. Here we revisit the origins of the effective
attractive interactions that emerge between and within macromolecules immersed
in solutions containing cosolutes that are preferentially excluded from the
macromolecular interfaces. Until recently, these depletion forces were
considered to be entropic in nature, resulting primarily from the tendency to
increase the space available to the cosolute. However, recent experimental
evidence indicates the existence of additional, energetically-dominated
mechanisms. In this review we follow the emerging characteristics of these
different mechanisms. By compiling a set of available thermodynamic data for
processes ranging from protein folding to protein-protein interactions, we show
that excluded cosolutes can act through two distinct mechanisms that correlate
to a large extent with their molecular properties. For many polymers at low to
moderate concentrations the steric interactions and molecular crowding effects
dominate, and the mechanism is entropic. To contrast, for many small excluded
solutes, such as naturally occurring osmolytes, the mechanism is dominated by
favorable enthalpy, whereas the entropic contribution is typically unfavorable.
We review the available models for these thermodynamic mechanisms, and comment
on the need for new models that would be able to explain the full range of
observed depletion forces.

16
The categories of this paper are: stat
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin