POLARIZED OPTICAL PROPERTIES OF PHYCOBILISOMES FROM Anabaena, Nostoc and Synechococcus

Polarized absorption, photoacoustic, fluorescence excitation and fluorescence emission spectra of phycobilisomes were measured when embedded in polyvinyl alcohol films. The phycobilisomes were isolated from the following organisms: Anabaena cylindrica, Nostoc punctiforma and Synechococcus elongatus. The ratio of photoacoustic spectra to absorption was taken as a measure of thermal dissipation of excitation energy. The isotropic samples and those oriented by the film stretching were investigated. The stretching of the sample strongly influences the efficiency of excitation energy transfer occurring among biliproteins in phycobilisomes, as is seen from the dramatic changes in the fluorescence and thermal dissipation spectra. The effect of stretching the film depends on the shape of phycobilisomes and on the strength of interactions between biliproteins in phycobilisomes.     

Synthesis of alkyl biphenyl-4-carboxylates by reaction of biphenyl with carbon tetrachloride and alcohols in the presence of Fe<Subscript>2</Subscript>(CO)<Subscript>9</Subscript>

Alkyl biphenyl-4-carboxylates have been synthesized with high selectivity by multicomponent reaction of biphenyl with carbon tetrachloride and aliphatic alcohols in the presence of iron-containing catalysts.     

On the magnitude of single-particle proton and neutron separation energies in the chains of isotopes and isotones near closed shells

Single-particle separation energies of protons or neutrons in nuclei near the closed shells are examined in the chains of isotopes or isotones. From the observed dependences we determine spins and parities of the single-particle orbitals and their sequence in nuclei far from the stability line, where direct experimental information on single-particle characteristics is not available at present.Received: 18 November 2003, Published online: 26 May 2004PACS: 21.10.Dr Binding energies and masses - 21.60.Cs Shell model - 21.10.Pc Single-particle levels and strength functions     

Essential reduction of discrepancies between mass values of nuclei withZ>N predicted by different approaches

Careful examination of discrepancies between mass values of nuclei withZ>N presented in different works enabled us the elucidation of the cause of these discrepancies and the selection of works whose results are the most plausible.     

On the reaction of nido-carborane with thiourea

Russian Chemical Bulletin - A reaction of the protonated form of 7,8-dicarba-nido-undecaborate anion 7,8-C2B9H13 with thiourea leads to the formation of a mixture of 9- and 10-thiuronium...