Electron-induced ionization and cationic fragmentations of the isolated molecule of 2,4-imidazolidinedione (hydantoin): a study of the relaxing path thresholds.

In this work, our new experimental setup has been used to study the ionization and fragmentation of a prebiotic molecule, hydantoin, by electron impact. Scanning of the incident electron energy allows the determination of the appearance thresholds of the cations. The vertical ionization potential was found to be in good agreement with previous data.

Comparison between gold nanoparticle and gold plane electron emissions: a way to identify secondary electron emission.

To understand the nanoparticle radiosensitising effect observed in the radiotherapy context, it is necessary to study the nanoparticle electron emission under x-ray irradiation, which is one of the causes of the radiosensitisation. In this paper, we compare the electron energy spectrum of gold samples irradiated by 1253.6 eV x-ray photons for energies down to 2 eV for nanoparticles and for a plane surface.

Proton-induced direct and indirect damage of plasmid DNA.

Clustered DNA damage induced by 10, 20 and 30 MeV protons in pBR322 plasmid DNA was investigated. Besides determination of strand breaks, additional lesions were detected using base excision repair enzymes. The plasmid was irradiated in dry form, where indirect radiation effects were almost fully suppressed, and in water solution containing only minimal residual radical scavenger.

Dehalogenation of 5-halo-uracil molecules induced by 100 keV proton collisions.

Neutral and cationic halogen loss of singly and doubly ionised 5-X-uracil (X = F, Cl, Br, I) after collisions with 100 keV protons have been studied in the gas phase. The rates of these dissociation channels are strongly dependant on the nature of the halogen substituent. It is very weak in the case of fluorine but is a dominant channel for iodine.