Converting ceria polyhedral nanoparticles into single-crystal nanospheres.

Ceria nanoparticles are one of the key abrasive materials for chemical-mechanical planarization of advanced integrated circuits. However, ceria nanoparticles synthesized by existing techniques are irregularly faceted, and they scratch the silicon wafers and increase defect concentrations. We developed an approach for large-scale synthesis of single-crystal ceria nanospheres that can reduce the polishing defects by 80% and increase the silica removal rate by 50%, facilitating precise and reliable mass-manufacturing of chips for nanoelectronics.

Valence fluctuations and metallic behavior in K6Cu12U2S15, a new quaternary sulfide with a unique three-dimensional cubic framework.

Mixed S2-/S1- oxidation states have been discovered in the new quaternary compound K6Cu12U2S15. Synthesized from the reaction of Cu and U in a molten alkali metal/polysulfide flux, the compound crystallizes in the cubic space group Ia3d (no. 230) with a = 18.

Metabolic fate of [13N]ammonia in human and canine blood.

Nitrogen-13- ([13N]) ammonia is a widely used tracer for PET myocardial blood flow studies. Quantification of blood flow using tracer kinetic principles requires accurate determination of [13N]ammonia activity in blood. Since [13N] ammonia is rapidly metabolized, the arterial input function may be contaminated by labeled metabolites.