Complex polymer architectures through dimethoxymethyl 1,1‐diphenylethylene derivatives

The reactions of polystyryllithium and potassium on dimethoxymethyl 1,1‐diphenylethylene derivatives were studied in different solvents. In a polar medium, A₃ and A₆ star types were formed according to the stoichiometry, whereas in a nonpolar medium, hyperbranched structures were synthesized. Extensions of an already proposed mechanism in polar and nonpolar media were examined. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3329–3335, 2003     

Analytical formulas for the velocity field induced by an infinitely thin vortex ring

Three different analytical solutions are presented for a potential vortex ring using three different streamfunctions. Verification studies confirm that all three approaches are valid. It is found that the solution obtained using the Biot–Savart law is the most efficient method due to its simplicity. It is shown that all analytical results are accurate to within machine accuracy and sample calculations are included. Copyright © 2004 John Wiley & Sons, Ltd.     

Microsatellite structures in the context of human evolution

Six microsatellite - or short tandem repeat (STR) - systems with uniform repetitive sequences (HumTH01, HumCD4, HumFES/FPS, HumF13B, HumTPO, HumLPL) and three compound repeat systems (HumVWA, HumFIBRA, D21S11) were used, including data from the literature, to determine genetic distances among eight populations worldwide. The TH01- and VWA homologous loci in nonhuman primates (chimpanzees, gorillas, orangutans, rhesus monkeys, ring-tailed lemurs) were compared and found to be shorter than in humans. Microsatellites of lower complexity were most efficient for the separation of major ethnic groups. The loci of higher complexity showed a leveling of the diversity differences among populations, which could be attributed to higher mutation rates.