An equilibrium theory of the length of intense electron bunches circulating in a storage ring is presented. The consequence of electrical interaction with various resonant structures is expressed in terms of quadratures over the impedance of the structures, and impedance functions for a variety of elements are evaluated. It is shown that elements having resonances at high frequency can, above transition, cause bunches to increase in length with increasing current. The parametric dependence of the bunch lengthening is found to be in good agreement with observations, and numerical estimates, which are in substantial agreement with experiment, are presented.

The carcinogenic activity of the benzo[a]pyrene 1, the 7,12-dimethylbenz[a]anthracene 2 and the 3-methylcholanthrene 3 is suggested to be determine by the electrophilic attack of the active oxygen, induced by the hydroxylating enzyme systems, on the most reactive substituting carbon atom(s). The cationic intermediate(s) with the charge mainly localized on a complementary, interrelated position(s) of the hydroxyl substituted position(s) reacts further with the cellular nucleophiles. The electrophilic nature of the ultimate chemical carcinogens constitutes the common distinctive feature that correlates their different structures and allows us to understand their carcinogenicity. The formation of a covalent bond with the nucleophiles of the biological macromolecules, nucleic acids and proteins, appears to be the essential requirement in the primary process of carcinogenesis.

None

None

Article discussing research on vegetative cells and cysts for Azotobacter vinelandii 12837 prepared for electron microscopy by several methods assumed to preserve structural details destroyed by techniques previously reported in literature.