SIMULATION OF THE RADIO-INDUIT DAMAGES BY PHOTONS ON THE DNA MOLECULE IN ITS ENVIRONMENT

Monte Carlo codes and equation of diffusion were successively, used to simulate the physical, and physico-chemical, and chemical steps that to estimate the simple and double strand breaks produced on a linear and hydrated DNA model by an incident photons beam. The increase of the biological effectiveness, between 150 and 550 eV, is mainly due to the variation of photon cross section upon the K- ionisation threshold in O,N,C atoms of DNA. In this study we present yields of main radiolysis species (e-aq, H, OH) as function of time, then parameterised by the concentration of solute such formicate (HCOO-). Moreover, we show that, with the same number of absorbed photons, the evolution of breaks as a function of energy reaches a maximum around 450 eV.

Keywords:

DNA, Monte Carlo, diffusion yields, solute, photons,

PDF

___

Saifi A.., Abdelmoumne M.E.K, Selmi S.,, "Survey of the products of the interaction of two distinct distributions of particles radiolytiques created at the time of the radiolyse of water by electrons ", Sc. & Tech., Univ. of Constantine, N°19 )2003(, pp.36-44.
Vrigneaud J.M., "Development of a biophysical model for the radio damage assessment led in the chromosomal fiber", Thesis of university Doctorate, CPAT of Toulouse, (2000), p. 98.
Terrissol M., "Method of simulation of the transportation of electrons of included energies between 10eV and 30keV", Thesis of besciences Doctorate, CPAT of Toulouse, (1978).
Saifi A., "Resolution of the diffusion equation by a semi-implicit method. Application to the case of the water radiolyse by electrons", Radiop., Vol.30, n°4, )1995(, pp.557-573.
Demonchy M., "Modelling of the primary effect of the radiances on the DNA in his/her/its environment", Thesis of university Doctorate, CPAT of Toulouse, (1997), p.46.
Biosym / Molecular simulation, to use guides 95.O, San Diego, THAT.(1995).
Demonchy M., Ph.D, Modélisation de l’effet primaire des rayonnements sur l’ADN dans son environnement, T ) CPAT de Toulouse 1997).
Vrigneaud J.M., "Development of a biophysical model for the radio damage assessment led in the chromosomal fiber", Thesis of university Doctorate, CPAT of Toulouse, (2000), p. 98.
La Verne.J.M, Pumblott.S.M., Effect elastic collisions on energy deposition by electrons in water, J.Phys. chem..A, 1997, 101, 45044510.
Burkert.U, Allinger.N.L., Molecular Mechanics, ACS Monograh177, American chemical Society, Washington, D.C,1982.
Oudira H., Djamai D., Saifi A., Application d’un modèle déterministe à l’étude de l’influence des molécules radioprotectrices sur les rendements des cassures simple et double brin de la molécule d’ADN, Radioprotection, 2008, 43, 389-408
CHATWITI .A. Ph.D, Etude de l’évolution temporelle des électrons dans un gaz faiblement ionisé, )Toulouse 1988(.
ZIENKIEWICZ .O.C.,) 1988( " La méthode des éléments finis :McGraw-Hill,1971.
Cullen D.E., "Tables and graphs of µ photon interaction cross-country section derived form the LLNL evaluated photon dated library, Z=1-50" Rad. Res.,Vol.6, part TO, Rev 4, Laurence Livemore Library, (1989).