Coprecipitation and Characterization of Na Substituted LiMn0.5Ni0.5O2 for Lithium ion Battery Cathodes

In this study, Li1-xNaxMn0.5Ni0.5O2 materials were successfully synthesized by co-precipitation following by solid state reaction method. X-ray powder diffraction analyses showed that the Li1-xNaxMn0.5Ni0.5O2 materials were single-phase and crystallized in a rhombohedral structure with a space group of R–3m at Na substitution concentrations of 0–20%. When increasing the concentration of Na substitution to 30%, diffraction peaks of Na2Mn3O7 as an impurity phase appeared in the X-ray diffraction pattern of the synthesized material. Rietveld refinements of the X-ray diffraction patterns revealed that the substitutions of Na for Li resulted in significant increments of the lattice constant c and slight increments of the lattice constant a. The results of galvanostatic charge/discharge measurements showed that the substitutions reduced the specific capacity but improved the rate capability of the Li0.8Na0.2Mn0.5Ni0.5O2 in comparison with the LiMn0.5Ni0.5O2 material.

Characterization of Influenza B Virus Variants with Reduced Neuraminidase Inhibitor Susceptibility

ABSTRACT Treatment options for influenza B virus infections are limited to neuraminidase inhibitors (NAIs), which block the neuraminidase (NA) glycoprotein on the virion surface. The development of NAI resistance would therefore result in a loss of antiviral treatment options for influenza B virus infections. This study characterized two contemporary influenza B viruses with known resistance-conferring NA amino acid substitutions, D197N and H273Y, detected during routine surveillance. The D197N and H273Y variants were characterized in vitro by assessing NA enzyme activity and affinity, as well as replication in cell culture compared to those of NAI-sensitive wild-type viruses. In vivo studies were also performed in ferrets to assess the replication and transmissibility of each variant. Mathematical models were used to analyze within-host and between-host fitness of variants relative to wild-type viruses. The data revealed that the H273Y variant had NA enzyme function similar to that of its wild type but had slightly reduced replication and transmission efficiency in vivo. The D197N variant had impaired NA enzyme function, but there was no evidence of reduction in replication or transmission efficiency in ferrets. Our data suggest that the influenza B virus variant with the H273Y NA substitution had a more notable reduction in fitness compared to wild-type viruses than the influenza B variant with the D197N NA substitution. Although a D197N variant is yet to become widespread, it is the most commonly detected NAI-resistant influenza B virus in surveillance studies. Our results highlight the need to carefully monitor circulating viruses for the spread of influenza B viruses with the D197N NA substitution.