Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct measurement of cell wall stress-stiffening and turgor pressure in
  live bacterial cells   We study intact and bulging Escherichia coli cells using atomic force
microscopy to separate the contributions of the cell wall and turgor pressure
to the overall cell stiffness. We find strong evidence of power-law
stress-stiffening in the E. coli cell wall, with an exponent of 1.22 \pm 0.12,
such that the wall is significantly stiffer in intact cells (E = 23 \pm 8 MPa
and 49 \pm 20 MPa in the axial and circumferential directions) than in
unpressurized sacculi. These measurements also indicate that the turgor
pressure in living cells E. coli is 29 \pm 3 kPa.

21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph