Adsorption parameters of Cu and Ni on the {110} plane of W and Mo

This paper reports on the embedded-atom method (EAM, developed by Johnson) calculations of adsorption parameters for Cu and Ni on {110} unrelaxed substrates of Mo and W. The following are calculated: (i) the equilibrium height h _c of an adatom; (ii) the optimum coefficients W ₀ A _hk of a truncated Fourier representation of the adatom-substrate interaction potential; (iii) the desorption energies E _des ; and (iv) the activation energies Q of surface migration. It is shown that (a) the calculated values of E _des agree satisfactorily with available empirical data; (b) the scale factor W ₀ is approximately proportional to the bonding as measured by E _des , whereas the normalized coefficients A _hk are determined by the {110} substrate symmetry; (c) E _des and Q are respectively dominated by the embedding energy and pair potential of the EAM; and (d) W ₀ and E _des for an atom in a monolayer are only about half as much as the corresponding quantities for an isolated atom.     

A fluorescence-quencher pair for DNA hybridization studies based on hydrophobic base surrogates

The synthesis of the novel, fluorescent 3-aminobiphenyl-C-nucleoside M as well as the corresponding building block for oligodeoxynucleotide synthesis is described. M was incorporated into oligodeoxynucleotides via standard phosphoramidite chemistry and the thermal stabilities of duplexes with one and three consecutive M-M, M-P, and M-O pairs, where P denotes an unmodified biphenyl C-nucleoside and O a 3,5-dinitrobiphenyl-C-nucleoside, were determined. It was found that duplexes containing three consecutive M-O pairs were the most stable in the series, notably more stable than a duplex with one additional natural G-C pair instead of the modified residues. Furthermore it was found that the fluorescence of M is efficiently quenched in a duplex when placed opposite to the dinitrophenyl unit O. Thus M and O constitute a novel fluorophore/quencher pair that is orthogonal to natural base pairs in its recognition properties enabling its use as highly specific tags with reporting properties.     

Mesocopic comparison of complex networks based on periodic orbits

Complex noiseless dynamical systems can be represented in a compressed manner by unstable periodic orbits. It is unknown, however, how to use this technique to obtain a suitable notion of similarity among them, how to extend such an approach to more general complex networks, and how to apply such a method in the important case of noisy systems. Our approach provides a solution to these questions. For a proof-of-concept, we consider Drosophila's precopulatory courtship, where our method reveals the existence of a complex grammar (similar to those found in complex physical systems and in language), leading to the conclusion that the observed grammar is very unlikely the product of chance.