Transition metal nitrides are of great technological and fundamental importance because of their strength and durability and because of their useful optical, electronic, and magnetic properties. We have evaluated a recently synthesized platinum nitride (PtN) that was shown to have a large bulk modulus, and we propose a structure that is isostructural with pyrite and has the stoichiometry PtN2. We have also synthesized a recoverable nitride of iridium under nearly the same conditions of pressure and temperature as PtN2. Although it has the same stoichiometry, it exhibits much lower structural symmetry. Preliminary results suggest that the bulk modulus of this material is also very large.

The processing-structure-property relationship is investigated for electrodeposited foils of the gold-copper alloy system. A model is presented that relates the deposition process parameters to the nanocrystalline grain size. An activation energy of 1.52 eV·atom -1 for growth is determined for a long pulse (>10 msec) mode, and is 0.16 eV·atom -1 for short pulses (<5 msec).The affect of nanocrystalline grain size on the mechanical properties is assessed using indentation measurements. A Hall-Petch type variation of the Vickers microhardness with nanocrystalline grain size (>6 nm) is observed for Au-Cu samples with 1-12 wt.% Cu as tested in cross-section. The hardness increases three-fold from a rule-of-mixtures value <1 GPa to a maximum of 2.9 GPa.2

Although acute gastroenteritis (AGE) has been reported as a common infectious disease in children, there is scarce information about enterovirus (EV) circulating associated with AGE cases in Brazil. The purpose of the present study was to identify and characterize the enteroviruses associated with AGE in children in Belém, Brazil. A total of 175 stool samples were obtained from children hospitalized revealing the presence of EV in 26.3% (46/175) of infections. EV type was identified in 78.3% (36/46) and EV-B species (61.1%; 22/36) was the most prevalent EV-detected followed by EV-C (25%; 9/36) and EV-A (13.9%; 5/36). This study has provided important information about the enterovirus circulation in Pará state, Northern Brazil.