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SUMMARY:Plasmon-induced DNA damage? - Prof. Zdenka Kuncic\, University of 
 Sidney
DTSTART:20101022T130000Z
DTEND:20101022T140000Z
UID:TALK26605@talks.cam.ac.uk
CONTACT:Erika Eiser
DESCRIPTION:The interaction of radiation (X-rays or electrons) with matter
  is of interest to a wide range of areas\, including: surface physics\, bi
 omedical imaging\, radiobiology and astrophysics. In the case of complex\,
  disordered\, soft targets such as biological\ntissue\, the interaction ph
 ysics is complicated by random scatterings\, particularly by electrons. At
  very low energies (< 100 eV)\, electrons undergo multiple elastic scatter
 ing\, but can also scatter inelastically off constituent atoms and molecul
 es of\nthe biological target\, resulting in excitations and ionizations. E
 lectron energy losses are determined by the dielectric response of the tar
 get and the differential interaction cross-section is usually calculated f
 rom scattering theory to within the first Born approximation. On a sub-cel
 lular level\, low-energy electrons are known to cause\nDNA damage and subs
 equent cell death by two methods: 1. directly\, through excitation/ionizat
 ion of sites in the DNA itself\, causing lesions such as single or\ndouble
  strand breaks\; or 2. indirectly\, by producing highly reactive radicals 
 in the surrounding water molecules\, which then react with the DNA. Cell i
 rradiation experiments have revealed that in some cases\, cells not direct
 ly exposed to radiation\, but in contact with irradiated cells\, can be ki
 lled. This bystander phenomenon remains unexplained. In this talk\, I will
  return to the basic physics of inelastic electron scattering in condensed
  matter and explore the possibility that plasmon excitations propagate bet
 ween adjacent cells to trigger the biochemical\nsignalling responsible for
  the DNA damage and subsequent death of cells that are not directly expose
 d to radiation.
LOCATION:Pippard Lecture Theatre\, Cavendish Laboratory
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