An efficient method for the asymmetric gold(I)-catalyzed preparation of medium sized rings has been developed. The method provides 7- to 9-membered rings in excellent yield. High enantioselectivities can be achieved for 7- and 8-membered ring products employing chiral gold(I) complexes. The results provide insight into the mechanism, showing the fluxional nature of gold(I)-stabilized vinyl carb...

We present the first experimental study on the simultaneous capillary instability amongst viscous concentric rings suspended atop an immiscible medium. The rings ruptured upon annealing, with three types of phase correlation between neighboring rings. In the case of weak substrate confinement, the rings ruptured independently when they were sparsely distanced, but via an out-of-phase mode when ...

Immune corneal ring reactions which were earlier defined in two distinct categories under the terms "systemic immune rings" and "local immune rings" have now been shown to be distinguishable by their mechanism of development. Local immune rings formed in properly sensitized corneas, in tissue culture and in whole enucleated eyes, with or without the inclusion of high titer immune serum in the m...

Subcortical fibrils composed of bundles of F-actin filaments and endoplasmic filaments are responsible for endoplasmic streaming. It is reported here that these fibrils and filaments move actively in an artificial medium containing Mg-ATP and sucrose at neutral pH, when the medium was added to the cytoplasm squeezed out of the cell. The movement was observed by phase-contrast microscopy or dark...

Concentrations of Pb in individual stem xylem rings of 5-year-old Norway spruce trees (Picea abies (L.) Karst.) were determined after one growing season in soil containing a low, medium or high concentration of Pb. In trees in the control and low-Pb soil treatments, Pb concentrations increased from the outer annual rings toward the stem center, whereas in trees grown in the soil treatment conta...