PURPOSE Polyamines are ubiquitous intracellular polycationic molecules essential for cell growth and differentiation. Polyamine analogs down-regulate ornithine decarboxylase, induce spermidine/spermine N1-acetyltransferase, deplete natural polyamine pools, inhibit growth, and induce programmed cell death in breast cancer models. This study evaluated the activity of the first-generation analog D...

Properties of a mutant form of spermidine/spermine N(1)-acetyltransferase, L156F (L156F-SSAT), that is present in Chinese hamster ovary cells selected for resistance to the polyamine analogue N(1,) N(11)-bis(ethyl)norspermine (BE 3-3-3) were investigated. Increased K(m) values, decreased V(max) values, and decreased k(cat) values with both polyamine substrates, spermidine and spermine, indicate...

We derive, for a bistochastic strictly contractive quantum channel on a matrix algebra, a relation between the contraction rate and the rate of entropy production. We also sketch some applications of our result to the statistical physics of irreversible processes and to quantum information processing. PACS numbers: 03.65.Yz, 03.67.-a, 05.30.-d Let A be the algebra of observables (say, a C*-alge...

The calculation of total integral cross sections for electron-impact ionization of atoms and atomic ions has, in the last 8 years, greatly benefited from the development of several nonperturbative methods, which generally show very good agreement with each other and with experiment. For the electron-impact ionization of hydrogen, the convergent close-coupling @1#, the hyperspherical close-coupl...

The elastic properties of a molecule of duplex DNA are strongly dependent on nucleotide sequence. In the theory developed here the contribution c of the nth base-pair step to the elastic energy is assumed to be given by a function c̃ of six kinematical variables, called tilt, roll, twist, shift, slide, and rise, that describe the relative orientation and displacement of the nth and (n11)th base ...