Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effect of intense, ultrashort laser pulses on DNA plasmids in their
  native state: strand breakages induced by {\it in-situ} electrons and
  radicals   Single strand breaks are induced in DNA plasmids, pBR322 and pUC19, in
aqueous media exposed to strong fields generated using ultrashort laser pulses
(820 nm wavelength, 45 fs pulse duration, 1 kHz repetition rate) at intensities
of 1-12 TW cm$^{-2}$. The strong fields generate, {\it in situ}, electrons and
radicals that induce transformation of supercoiled DNA into relaxed DNA, the
extent of which is quantified. Introduction of electron and radical scavengers
inhibits DNA damage; results indicate that OH radicals are the primary (but not
sole) cause of DNA damage.

29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci