High-pressure structural, elastic, and thermodynamic properties of zircon-type HoPO4 and TmPO4

Zircon-type HoPO4 and TmPO4 have been studied by single-crystal x-ray diffraction and ab initio calculations. We report information on the influence of pressure on the crystal structure, and on the elastic and thermodynamic properties. The equation of state for both compounds is accurately determined. We have also obtained information on the polyhedral compressibility which is used to explain the anisotropic axial compressibility and the bulk compressibility. Both compounds are ductile and more resistive to volume compression than to shear deformation at all pressures. Furthermore, the elastic anisotropy is enhanced upon compression. Finally, the calculations indicate that the possible causes that make unstable the zircon structure are mechanical instabilities and the softening of a silent B1u mode

Structural and vibrational study of pseudocubic CdIn2Se4 under compression

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry C, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/jp5077565We report a comprehensive experimental and theoretical study of the structural and vibrational properties of a-CdIn2Se4 under compression. Angle-dispersive synchrotron X-ray diffraction and Raman spectroscopy evidence that this ordered-vacancy compound with pseudocubic structure undergoes a phase transition (7 GPa) toward a disordered rocksalt structure as observed in many other ordered-vacancy compounds. The equation of state and the pressure dependence of the Raman-active modes of this semiconductor have been determined and compared both to ab initio total energy and lattice dynamics calculations and to related compounds. Interestingly, on decreasing pressure, at similar to 2 GPa, CdIn2Se4 transforms into a spinel structure which, according to calculations, is energetically competitive with the initial pseudocubic phase. The phase behavior of this compound under compression and the structural and compressibility trends in AB(2)Se(4) selenides are discussed.This study was supported by the Spanish government MEC under Grant Nos: MAT2013-46649-C4-3-P, MAT2013-46649-C4-2-P, MAT2010-21270-C04-03/04, and CTQ2009-14596-C02-01, by MALTA Consolider Ingenio 2010 Project (CSD2007-00045) and by Generalitat Valenciana (GVA-ACOMP-2013-1012). A.M. and P.R-H. acknowledge computing time provided by Red Espanola de Supercomputacion (RES) and MALTA-Cluster, and also to S. Munoz-Rodriguez for providing a data-parsing application. J.A.S. acknowledges Juan de la Cierva fellowship program for financial support.Santamaría Pérez, D.; Gomis, O.; Pereira, ALJ.; Vilaplana Cerda, RI.; Popescu, C.; Sans Tresserras, JÁ.; Manjón Herrera, FJ.... (2014). Structural and vibrational study of pseudocubic CdIn2Se4 under compression. Journal of Physical Chemistry C. 118(46):26987-26999. https://doi.org/10.1021/jp5077565S26987269991184

Lattice dynamics study of HgGa2Se4 at high pressures

We report on Raman scattering measurements in mercury digallium selenide (HgGa2Se4) up to 25 GPa. We also performed, for the low-pressure defect-chalcopyrite structure, lattice-dynamics ab initio calculations at high pressures which agree with experiments. Measurements evidence that the semiconductor HgGa2Se4 exhibits a pressure-induced phase transition above 19 GPa to a previously undetected structure. This transition is followed by a transformation to a Raman-inactive phase above 23.4 GPa. On downstroke from 25 GPa until 2.5 GPa, a broad Raman spectrum was observed, which has been attributed to a fourth phase, and whose pressure dependence was followed during a second upstroke. Candidate structures for the three phases detected under compression are proposed. Finally, we also report and discuss the decomposition of the sample by laser heating at pressures close to 19 GPa. As possible products of decomposition, we have identified at least the formation of trigonal selenium nanoclusters and cinnabar-type HgSe.This study was supported by the Spanish government MEC under Grant No. MAT2010-21270-004-01/03/04, by MALTA Consolider Ingenio 2010 project (CSD2007-00045), by Generalitat Valenciana through project GVA-ACOMP-2013-012, and by the Vicerrectorado de Investigacion y Desarrollo of the Universidad Politecnica de Valencia (UPV2011-0966 and UPV2011-0914). E.P.-G., J.L.-S., A.M., and P.R.-H. acknowledge computing time provided by Red Espanola de Super-computacion (RES) and MALTA-Cluster.Vilaplana Cerda, RI.; Gomis Hilario, O.; Manjón Herrera, FJ.; Ortiz, HM.; Pérez González, E.; López Solano, J.; Rodríguez Hernández, P.... (2013). Lattice dynamics study of HgGa2Se4 at high pressures. Journal of Physical Chemistry C. 117(30):15773-15781. https://doi.org/10.1021/jp402493rS15773157811173

Inborn errors of OAS-RNase L in SARS-CoV-2-related multisystem inflammatory syndrome in children

Multisystem inflammatory syndrome in children (MIS-C) is a rare and severe condition that follows benign COVID-19. We report autosomal recessive deficiencies of OAS1, OAS2, or RNASEL in five unrelated children with MIS-C. The cytosolic double-stranded RNA (dsRNA)-sensing OAS1 and OAS2 generate 2'-5'-linked oligoadenylates (2-5A) that activate the single-stranded RNA-degrading ribonuclease L (RNase L). Monocytic cell lines and primary myeloid cells with OAS1, OAS2, or RNase L deficiencies produce excessive amounts of inflammatory cytokines upon dsRNA or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) stimulation. Exogenous 2-5A suppresses cytokine production in OAS1-deficient but not RNase L-deficient cells. Cytokine production in RNase L-deficient cells is impaired by MDA5 or RIG-I deficiency and abolished by mitochondrial antiviral-signaling protein (MAVS) deficiency. Recessive OAS-RNase L deficiencies in these patients unleash the production of SARS-CoV-2-triggered, MAVS-mediated inflammatory cytokines by mononuclear phagocytes, thereby underlying MIS-C