Contrasting Surface Behavior of Rh (111) and Pt (111) Electrodes

Low energy electron diffraction and voltammetric measurements of the Rh(lll) electrode were conducted and compared with the corresponding surface and electrochemical characteristics of Pt (111). Rhodium is unstable upon exposure to water vapor or liquid water, but retains its well-defined character after immersion to aqueous media. This is reflected in the voltammetric behavior of the clean surface, as well as the manner in which carbon monoxide and iodine are adsorbed from solution. That is, a monolayer of an oxygen-containing species, assembled into (2X2) surface structure, can either be reduced by the voltammetric treatment or replaced by adsorbing solution components without causing system disorder. The voltammetry of the Rh (111) electrode, while exhibiting the main features of several metallic single crystal surfaces, differs significantly from that of platinum electrodes normalized to the same 2D geometry. From the voltam- me\u27ric behavior, it is concluded that adsorption of high energy hydrogen is not taking place on Rh (111). Equally important, the packing density and the surface structure of the Rh(lll) — CO differs from its Pt(lll) — CO analog. While iodine chemisorption from the gas phase leads to the development of several surface structures known from the corresponding platinum work, preferential formation of the_Pt (111) (V3 X V3)R30°—I structure against the Pt(lll)(V7X V7)R19.1°—I was demonstrated. Both electronic and structural factors contribute to the contrasting surface behavior brought to focus in this work

Genetic Variations among Different Variants of G1-like Avian Influenza H9N2 Viruses and Their Pathogenicity in Chickens

Since it was first discovered, the low pathogenic avian influenza (LPAI) H9N2 subtype has established linages infecting the poultry population globally and has become one of the most prevalent influenza subtypes in domestic poultry. Several different variants and genotypes of LPAI H9N2 viruses have been reported in Egypt, but little is known about their pathogenicity and how they have evolved. In this study, four different Egyptian LPAI H9N2 viruses were genetically and antigenically characterized and compared to representative H9N2 viruses from G1 lineage. Furthermore, the pathogenicity of three genetically distinct Egyptian LPAI H9N2 viruses was assessed by experimental infection in chickens. Whole-genome sequencing revealed that the H9N2 virus of the Egy-2 G1-B lineage (pigeon-like) has become the dominant circulating H9N2 genotype in Egypt since 2016. Considerable variation in virus shedding at day 7 post-infections was detected in infected chickens, but no significant difference in pathogenicity was found between the infected groups. The rapid spread and emergence of new genotypes of the influenza viruses pinpoint the importance of continuous surveillance for the detection of novel reassortant viruses, as well as monitoring the viral evolution