C-X (X = N, O) Cross-Coupling Reactions Catalyzed by Copper-Pincer Bis(N-Heterocyclic Carbene) Complexes.

Over the last two decades, N-heterocyclic carbene (NHC)-copper catalysts have received considerable attention in organic synthesis. Despite the popularity of copper complexes containing monodentate NHC ligands and recent development of poly(NHC) platforms, their application in C-C and C-heteroatom cross-coupling reactions has been limited. Recently, we reported an air-assisted Sonogashira-type cross-coupling catalyzed by well-defined cationic copper-pincer bis(NHC) complexes.

Measurement of cryoprotective solvent penetration into intact organ tissues using high-field NMR microimaging.

Existing methods are not able to monitor accurately the penetration of cryoprotective solvents (CPS) into intact tissues. In this study, NMR imaging is shown to be a noninvasive nondestructive way to measure penetration rates and effective diffusion coefficients of Me2SO into samples of rat kidney and rat liver tissues. This new method is unique in that the measurements obtained are not averaged over the entire tissue volume but may be made at any site in the tissue.

Malpractice premiums in 1992: results of a national survey of dentists.

According to a 1992 national survey, more than 95 percent of general dentists in the United States purchased malpractice insurance. The authors evaluated the survey findings to identify factors that had the greatest effect on dentists' insurance premium costs. Premiums were higher for dentists who had been the subject of previous complaints or claims, as well as for those who owned their practices.