QUANTITATIVE 252Cf-PDMS FOR ETOPOSIDE

Les sérum de patients traités par étoposide ont été marqués par téniposide, un composé analogue, puis extraits. La purification des échantillons a été obtenue par chromatographie en couches fines et l'analyse quantitative realisée par 252Cf-PDMS. L'addition de substances adéquates en excès à la cible finale PDMS améliore la sensibilité et la linéarité de cette analyse quantitative.Serum samples from cancer patients, who were treated with etoposide, are labeled with the homologous compound teniposide as internal standard and extracted. Sample purification is achieved by thin layer chromatography and the quantitative analysis is performed by 252Cf-PDMS. Adding suitable substances in excess to the final PDMS target is an effective tool to improve the sensitivity and linearity of this quantitative analysis

Lifetimes of collective resonance states (excimols) in polyatomic regular type molecules and clusters

A model to estimate lifetimes of excited collective resonance states (excimols) for large biomolecules or clusters, which have a regular or close to regular structure, is presented. These collective excited states arise due to resonance excitation of one or a few bonds in the constituents of the system. The model is based on the quantum multi-particle theory and the exciton or the excimol theory for the condensed matter and molecules. The spectral analysis for non-self-adjoined energy operators is used in the model. As an example, lifetimes are calculated for one-dimensional chain-like polyatomic molecules and for clusters formed by such molecules. The resulting lifetimes of the entire excitation are longer than the lifetimes of the initial trigger excitation.

Corrosion properties of ion beam modified fullerene thin films on iron substrates

The corrosion behavior of fullerene coated iron samples was investigated by using electrochemical techniques. Fullerene was deposited on iron substrates via thermal evaporation under high vacuum conditions. Subsequent sample preparation included heat treatment as well as Ar+ ion irradiation under various conditions, which were carried out to modify the fullerene coatings. Changes in the structure of the films due to the treatment were analyzed by Raman spectroscopy. To reveal the samples’ corrosion behavior, cyclovoltammetric measurements were performed in a weakly acidic aqueous medium particularly with regard to possible corrosion protective properties. As the results show, Ar-ion treatment of the fullerene films leads to considerably increased corrosion resistance, which is due to formation of a dense amorphous carbon network. In contrast, heat treatment of the fullerene films increases the corrosion rates, presumably due to formation of iron carbide, which leads to galvanic corrosion