Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comment on "Pinched Flow Fractionation: Continuous Size Separation of
  Particles Utilizing a Laminar Flow Profile in a Pinched Microchannel"   [First paragraph] In a recent paper Yamada et al. propose the novel concept
of "pinched flow fractionation" (PFF) for the continuous size separation and
analysis of particles in microfabricated lab-on-a-chip devices. In their
description of the basic principle they claim that especially the width of the
pinched and broadened segments will affect theseparation performance. In the
following we comment on the physics behind this statement.

37
The categories of this paper are: supr-con
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex