Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Epithelia are multiscale active liquid crystals   Biological processes such as embryogenesis, wound healing and cancer
progression, crucially rely on the ability of epithelial cells to coordinate
their mechanical activity over length scales order of magnitudes larger than
the typical cellular size. While regulated by signalling pathways, such as YAP
(yes-associated protein), MAPK (mitogen-activated protein kinase) and Wnt, this
behavior is believed to additionally hinge on a minimal toolkit of physical
mechanisms, of which liquid crystal order is the most promising candidat. Yet,
experimental and theoretical studies have given so far inconsistent results in
this respect: whereas nematic order is often invoked in the interpretation of
experimental data, computational models have instead suggested that hexatic
order could in fact emerge in the biologically relevant region of parameter
space. In this article we resolve this dilemma. Using a combination of in vitro
experiments on Madin-Darby canine kidney cells (MDCK), numerical simulations
and analytical work, we demonstrate that both nematic and hexatic order is in
fact present in epithelial layers, with the former being dominant at large
length scales and the latter at small length scales. In MDCK GII cells on
uncoated glass, these different types of liquid crystal order crossover at $34
\mu$m, corresponding approximatively to clusters of $21$ cells. Our work sheds
light on the emergent organization of living matter, provides a new set of
tools for analyzing the structure of epithelia and paves the way toward a
comprehensive and predictive mesoscopic theory of tissues.

23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs