A rigorous implementation of the Jeans--Landau--Teller approximation

Rigorous bounds on the rate of energy exchanges between vibrational and translational degrees of freedom are established in simple classical models of diatomic molecules. The results are in agreement with an elementary approximation introduced by Landau and Teller. The method is perturbative theory ``beyond all orders'', with diagrammatic techniques (tree expansions) to organize and manipulate terms, and look for compensations, like in recent studies on KAM theorem homoclinic splitting.Comment: 23 pages, postscrip

Simple and sensitive screening and quantitative determination of 88 psychoactive drugs and their metabolites in blood through LC-MS/MS: Application on postmortem samples

The aim of the study was to develop and validate a simple, sensitive and specific method for the detection and quantitative determination of 88 substances among psychoactive drugs and their metabolites in whole blood, and to apply the procedure to postmortem cases. Samples were consecutively diluted with methanol, acetonitrile and mobile phase. All the molecules were separated and then identified through a liquid chromatographic, tandem mass spectrometric system, and eventually fully validated according to the international guidelines. The method proved to be highly sensitive and specific and all the validation parameters fulfilled the acceptance criteria. In particular linearity was studied in the range LOQ-1000. ng/mL; matrix effects and carry over were negligible and the majority of the compounds assessed to be stable over several freeze and thaw processes. Olanzapine is the most unstable compound. Protryptiline and flupenthixol did not fulfilled acceptance criteria, and although their transitions were kept on the instrumental settings, they were not considered for the fully validation. The method was applied to several postmortem cases, and the results were compared to the GC-MS systematic toxicological analysis currently in use in our laboratory, assessing to be a good complementary procedure and providing a better sensitivity. The LC-MS/MS method could be easily applicable to routine analyses of postmortem samples, as well as to a screening procedure for clinical purposes; however it should be carried out in combination with a general unknown screening method