Localized and delocalized bound states of the main isotopologue O and of O-enriched O isotopomers of the ozone molecule near the dissociation threshold.

Knowledge of highly excited rovibrational states of ozone isotopologues is of key importance for modelling the dynamics of exchange reactions, for understanding longstanding problems related to isotopic anomalies of the ozone formation, and for analyses of extra-sensitive laser spectral experiments currently in progress. This work is devoted to new theoretical study of high-energy states for the main isotopologue 48O3 = 16O16O16O and for the family of 18O-enriched isotopomers 50O3 = {16O16O18O, 16O18O16O, 18O16O16O} of the ozone molecule considered using a full-symmetry approach. Energies and wave functions of bound states near the dissociation threshold are computed in hyperspherical coordinates accounting for the permutation symmetry of three identical nuclei in 48O3 and of two identical nuclei in 50O3, using the most accurate potential energy surface available now.

The Role of Ozone Vibrational Resonances in the Isotope Exchange Reaction OO + O → OO + O: The Time-Dependent Picture.

We consider the time-dependent dynamics of the isotope exchange reaction in collisions between an oxygen molecule and an oxygen atom: OO + O → OO + O. A theoretical approach using the multiconfiguration time-dependent Hartree method was employed to model the time evolution of the reaction. Two potential surfaces available in the literature were used in the calculations, and the results obtained with the two surfaces are compared with each other as well as with results of a previous theoretical time-independent approach.

Versican isoforms modulate expression and function of nicotinic acetylcholine receptors.

Versican is a chondroitin sulfate proteoglycan whose isoforms are differentially expressed, but little is known of their functions in the neuronal system. Here we show that isoforms of versican play different roles in neuronal differentiation and neurite outgrowth. Expression of versican V1 isoform in PC12 cells induced complete neuronal differentiation and increased the expression of nicotinic acetylcholine receptor in NGF-independent manners.

The ability of versican to simultaneously cause apoptotic resistance and sensitivity.

Expression of the extracellular matrix proteoglycan versican is associated with more than 10 types of cancers, often being secreted by stromal cells in response to tumor signals. Previous work in our lab has shown that overexpression of the V1 versican isoform in cultured fibroblasts (V1 cells) increases both proliferation and apoptotic resistance. We show here that V1 cells induced tumor formation in nude mice and that, in keeping with previously shown apoptotic resistance, V1 cells have down-regulated Fas mRNA and protein levels.