Delocalization quantitatively mapped for prototypic organic nitroanions as well as azidoform anions.

Delocalization of occupied orbitals impacts the chemical bonding in the simplest known pernitroanions [(NO)C] (1) and [(NO)N] (2) as well as other functionalized organic anions. By quantitatively mapping it onto molecular backbones of 1, 2, [CHNO] (3), [CHNNO] (4) and [C(N)] (6) anions (all modeled by QM calculations), the Weinhold's NBO analysis refines their chemical structure, enabling to explain and even predict their essential chemical behaviour. In detail, the HOMO of 1 and 2 is associated with the central atom to the degree of 70.

Nanosecond-Scale Isomerization of the 4'-Carboxonium Cation Oxidatively Produced in Pyrimidine Units of DNA.

The long-standing puzzle of the chemistry producing the Stubbe-Kozarich abasic site, which is the minor product in the oxidation of 2'-deoxycytidine units of DNA by Fe(II)-bleomycin, has been computationally solved in this study. Scrupulous DFT-based calculations that included extensive screening of the potential energy surface of model-solvated nucleotides and the elucidation of the chemical structure of the located nucleotide cations via natural bond orbital analysis demonstrated that the 2'-deoxycytidine unit bearing the 2'-deoxyribose ring 2e-oxidized at the 4'-position undergoes carboxonium ion- iminium ion (C═O-C → C═N) isomerization. This 1,2-elimination of the carbonyl group 4'-C═O from the carboxonium cation fragment is associated with minimal spatial reorganization of the molecule and appears to be an ultrafast reaction.

[The actual issues of development of manpower potential in health care].

The analysis was implemented concerning main directions of development of health care manpower policy in Moscow. The activities are established related to improvement of actual situation with development of potential of medical personnel, increasing of motivation ofphysicians and paramedical personnel, improvement of conditions of development of manpower resources.

[Higher mental functions and cognitive auditory event-related potentials impairment in liquidators of Chernobyl accident].

An integrated neuropsychological study and analysis of cognitive auditory event-related potentials (ERP) using the three-stimulus oddball paradigm was performed in ten subjects who participated in the liquidation of Chernobyl accident and ten healthy subjects. Impairment of higher mental functions, including aspontaneity, fatigability, a decrease in the auditory-verbal and visual memories, and higher motor function deficiency was shown in liquidators. A decrease of amplitude in all components of ERP (N1, N2 and P3) was found in liquidators for all stimuli in both experimental situations (audition of all stimuli and counting of deviant stimuli) compared to healthy subjects.

Essential reactive intermediates in nucleoside chemistry: cyclonucleoside cations.

DFT-based modeling as well as experimental examination of model keto nucleosides have revealed that high susceptibility of these compounds to acids is due to formation of intermediate cyclonucleoside cations of low energy. Theoretically established chemical structures of these previously overlooked intermediates explain the reaction courses for a cluster of nucleoside reactions.