23 research outputs found
Observation of Strong Resonant Behavior in the Inverse Photoelectron Spectroscopy of Ce Oxide
X-ray emission spectroscopy and resonant inverse photoelectron spectroscopy (RIPES) have been used to investigate the photon emission associated with the Ce 3d5/2 and Ce 3d3/2 thresholds. Strong resonant behavior has been observed in the RIPES of a Ce oxide near the 5/2 and 3/2 edges
ACBD5 and VAPB mediate membrane associations between peroxisomes and the ER
This is the final version of the article. Available from the publisher via the DOI in this record.Peroxisomes (POs) and the endoplasmic reticulum (ER) cooperate in cellular lipid metabolism and form tight structural
associations, which were first observed in ultrastructural studies decades ago. POâER associations have been suggested
to impact on a diverse number of physiological processes, including lipid metabolism, phospholipid exchange, metabolite
transport, signaling, and PO biogenesis. Despite their fundamental importance to cell metabolism, the mechanisms
by which regions of the ER become tethered to POs are unknown, in particular in mammalian cells. Here, we identify
the PO membrane protein acyl-coenzyme Aâbinding domain protein 5 (ACBD5) as a binding partner for the resident
ER protein vesicle-associated membrane protein-associated protein B (VAPB). We show that ACBD5âVAPB interaction
regulates POâER associations. Moreover, we demonstrate that loss of POâER association perturbs PO membrane expansion
and increases PO movement. Our findings reveal the first molecular mechanism for establishing POâER associations
in mammalian cells and report a new function for ACBD5 in POâER tethering.This work was supported by grants from the Biotechnology and Biological
Sciences Research Council (BB/K006231/1 and BB/
N01541X/1 to M. Schrader). J. Metz and M. Schrader are supported
by a Wellcome Trust Institutional Strategic Support Award
(WT097835MF and WT105618MA) and L.F. Godinho by a fellowship
from Fundação para a CiĂȘncia e a Tecnologia, Portugal (SFRH/
BPD/90084/2012). M. Schrader and A.S. Azadi are supported by
Marie Curie Initial Training Network action PerFuMe (316723).
M. Islinger is supported by MEAMEDMA Anschubförderung, Medical
Faculty Mannheim, University of Heidelberg
Soft x-ray absorption and emission spectra and the electronic structure of the superconductor
We present e-beam-excited soft-x-ray emission spectra and total-photoelectron-yield spectra in the 20â600 eV photon energy range for . In soft x-ray emission, the N4,5 structure of Ba, the M4,5 spectrum of Y, and the K spectrum of O provide a direct measure of the p-type partial density of states (p-PDOS) localized on the respective atomic sites. In each case the p-PDOS is very small at the Fermi energy ÉF. The maximum in the O K spectrum is 2.6±0.5 eV below ÉF. This result provides direct confirmation that the shoulder previously found at É-2.3 eV in photoelectron emission spectra is associated with O p orbitals. No changes are observed between spectra taken above and below Tc. .A
Orbital dynamics during an ultrafast insulator to metal transition
We present ultrafast resonant inelastic x-ray scattering (RIXS) experiments performed at the vanadium L edge to track changes in the electronic structure of V2O3, a classical Mott-Hubbard material. The probed orbital excitations within the d shell of the V ion show a sub-ps time response, which evolves at later times to a state that appears electronically indistinguishable from the high-temperature metallic state. For low excitation fluences, a transient recovery or delay is observed, which could be related to a transient dimerization of the V-V bonds. Our results demonstrate the great potential for RIXS spectroscopy to study the ultrafast orbital dynamics in strongly correlated materials