Population snapshot of Streptococcus pneumoniae serotype 19A isolates before and after introduction of seven-valent pneumococcal Vaccination for French children.

Serotype 19A Streptococcus pneumoniae strains are now more frequent in French children than before the introduction of a seven-valent conjugate vaccine (PCV7). By applying multilocus sequence typing to 144 serotype 19A isolates collected before and after beginning PCV7 vaccination, we detected clonal expansion of the preexisting penicillin-intermediate sequence type 276.

Electronic and photophysical properties of a novel phenol bound dinuclear ruthenium complex: evidence for a luminescent mixed valence state.

A novel dinuclear ruthenium(II) complex bridged by dianionic bridge 3-(2-phenol)-5-(pyridin-2-yl)-1,2,4-triazole in which the ruthenium metal atoms are bound through N,N coordination to the pyridine and triazole and O,N coordination to the triazole and phenolate is described. The electrochemical, spectroscopic and photophysical behaviour of the dimer is compared with its associated N,N- and O,N-coordinated mononuclear complexes. The mixed valence complex was prepared electrochemically and a weak inter-valence charge transfer transition is observed which from Hush theory provides an electronic coupling matrix element of 666 cm(-1), suggesting the complex is weakly coupled and valence trapped. In its native state the dinuclear compound is essentially non-emissive but upon the oxidation of the O,N moiety luminescence from the complex is reversibly switched on at 0.3 V and reversibly switched off by application of 1.3 or 0 V. To our knowledge this is the first report of a luminescent mixed valence ruthenium complex.