Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectroscopic investigation of local mechanical impedance of living
  cells   The mechanical properties of PC12 living cells have been studied at the
nanoscale with a Force Feedback Microscope using two experimental approaches.
Firstly, the local mechanical impedance of the cell membrane has been mapped
simultaneously to the cell morphology at constant force. As the force of the
interaction is gradually increased, we observed the appearance of the
sub-membrane cytoskeleton. We shall compare the results obtained with this
method with the measurement of other existing techniques. Secondly, a
spectroscopic investigation has been performed varying the indentation of the
tip in the cell membrane and consequently the force applied on it. In contrast
with conventional dynamic atomic force microscopy techniques, here the small
oscillation amplitude of the tip is not necessarily imposed at the cantilever
first eigenmode. This allows the user to arbitrarily choose the excitation
frequency in developing spectroscopic AFM techniques. The mechanical response
of the PC12 cell membrane is found to be frequency dependent in the 1 kHz - 10
kHz range. The damping coefficient is reproducibly observed to decrease when
the excitation frequency is increased.

35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
19
The categories of this paper are: eess
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph