Small peptide libraries: combinatorial split-mix synthesis followed by combinatorial amino acid analysis of selected variants

Peptides from small combinatorial libraries, covalently attached to polymeric TentaGel beads, can be directly sequenced using amino acid analysis. For libraries with restricted diversity, generated by the split-mix synthesis method, the amino acids on a selected single bead identified by pre-column derivatization with o-phthaldialdehyde (OPA) correlate directly with the sequence of a given peptide. This is shown on a tripeptide (343 different compounds) and a tetrapeptide (4096 different compounds) library. This method allows for rapid peptide sequence determination without relying on complex encoding strategies.

Convergence to spatial-temporal clines in the Fisher equation with time-periodic fitnesses

The asymptotic behavior as t----infinity of the solutions with values in the interval (0, 1) of a reaction-diffusion equation of the form (Formula: see text) is studied. Conditions on m which are satisfied when m is nonincreasing in mu and which imply that every solution converges to some periodic limit function are found. Except in some very special and well-defined circumstances, the limit is the same for all solutions, so that it is a global attractor. This global attractor may be one of the trivial solutions 0 or 1, or it may be a spatial-temporal cline. The linear stability properties of the trivial states serve to distinguish between these cases.

Interference method for pattern comparison

A test pattern may be compared with a reference pattern by placing the two side by side in a coherent beam. If the compared patterns are sufficiently similar, regular parallel fringes will modulate the common Fraunhofer diffraction pattern of the compared samples. The regularity of the interference fringes is a measure of the similarity between the compared patterns. The sensitivity of the method is not disturbed by small absolute and relative displacements of test and reference signals. The effect of even small rotations is, however, severe. The effect of random noise is to reduce the contrast of the interference fringes.