Donor-/Acceptor-Substituted Tetrakis(arylethynyl)benzenes: The Influence of Donor Group on Optoelectronic Properties.

We have prepared nine structural isomers of a tetrakis(arylethynyl)benzene chromophore functionalized with 4-butoxyphenyl and pyridyl units as the respective donor and acceptor units and examined their steady-state spectroscopic parameters to study how small structural variations effect the electronic absorption and emission spectra. Unlike their 4-dibutylaminophenyl congeners that exhibited dynamic hypsochromic or bathochromic shifts in response to Lewis and Brønsted acids, the current class of compounds simply showed quenched fluorescence upon protonation; only AlCl elicited a red-shifted fluorescence response. Computational studies of each system were also performed to provide additional insight into the energy levels and electronic transitions present.

[Characteristics of the influenza type A (H3N2) epidemic in Omsk in January 1985].

The work presents the data obtained in analysis of the epidemic situation among the population of Omsk in January-February 1985 and the characterization of the isolated strains of influenza A (H3N2) virus, determines the specific features of the course of the influenza epidemic process among different social and age groups, evaluates anti-influenza measures.

Stereospecificity of sodium borohydride reduction of tyrosine decarboxylase from Streptococcus faecalis.

Sodium boro[3H]hydride reduction of tyrosine decarboxylase from Streptococcus faecalis followed by complete hydrolysis of the enzyme produces epsilon-[3H]pyridoxyllysine. Degradation of this material to [4'-3H]pyridoxamine and stereochemical analysis with apoaspartate aminotransferase shows that the re side at C-4' of the cofactor is exposed to solvent at pH 5.5 and 7.