Current Understanding of Structure–Processing–Property Relationships in BaTiO₃–Bi(M)O₃ Dielectrics

As part of a continued push for high permittivity dielectrics suitable for use at elevated operating temperatures and/or large electric fields, modifications of BaTiO3 with Bi(M)O3, where M represents a net-trivalent B-site occupied by one or more species, have received a great deal of recent attention. Materials in this composition family exhibit weakly coupled relaxor behavior that is not only remarkably stable at high temperatures and under large electric fields, but is also quite similar across various identities of M. Moderate levels of Bi content (as much as 50 mol%) appear to be crucial to the stability of the dielectric response. In addition, the presence of significant Bi reduces the processing temperatures required for densification and increases the required oxygen content in processing atmospheres relative to traditional X7R-type BaTiO3-based dielectrics. Although detailed understanding of the structure–processing–property relationships in this class of materials is still in its infancy, this article reviews the current state of understanding of the mechanisms underlying the high and stable values of both relative permittivity and resistivity that are characteristic of BaTiO3-Bi(M)O3 dielectrics as well as the processing challenges and opportunities associated with these materials

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Effects of Molecular Crowding on Protein Self-Association: A Potential Source of Error in Sedimentation Coefficients Obtained by Zonal Ultracentrifugation in a Sucrose Gradient

Theoretical and experimental studies have illustrated a potential source of error in sedimentation coefficients obtained by sucrose density gradient centrifugation of proteins undergoing reversible self association. The error stems from the excluded volume (molecular crowding) effect of the sucrose on the activity coefficients of monomeric and polymeric states. The consequent displacement of the equilibrium position in favor of polymeric state(s) is a function of sucrose concentration, and can therefore result in failure to detect the equilibrium coexistence of monomer if 5% sucrose suffices to displace the equilibrium completely toward dimer. In less extreme situations, it may result in the evaluation of an average sedimentation coefficient whose magnitude is a function of sucrose concentration and hence of the distance migrated into the sucrose gradient. These features are illustrated by the results of computer-simulated sedimentation of reversibly dimerizing systems in a sucrose gradient, and by conventional sedimentation velocity experiments on yeast enolase