TY  - JOUR
A1  - Gabel, Judith
A1  - Pickem, Matthias
A1  - Scheiderer, Philipp
A1  - Dudy, Lenart
A1  - Leikert, Berengar
A1  - Fuchs, Marius
A1  - Stübinger, Martin
A1  - Schmitt, Matthias
A1  - Küspert, Julia
A1  - Sangiovanni, Giorgio
A1  - Tomczak, Jan M.
A1  - Held, Karsten
A1  - Lee, Tien–Lin
A1  - Claessen, Ralph
A1  - Sing, Michael
T1  - Toward Functionalized Ultrathin Oxide Films: The Impact of Surface Apical Oxygen
JF  - Advanced Electronic Materials
N2  - Thin films of transition metal oxides open up a gateway to nanoscale electronic devices beyond silicon characterized by novel electronic functionalities. While such films are commonly prepared in an oxygen atmosphere, they are typically considered to be ideally terminated with the stoichiometric composition. Using the prototypical correlated metal SrVO\(_{3}\) as an example, it is demonstrated that this idealized description overlooks an essential ingredient: oxygen adsorbing at the surface apical sites. The oxygen adatoms, which are present even if the films are kept in an ultrahigh vacuum environment and not explicitly exposed to air, are shown to severely affect the intrinsic electronic structure of a transition metal oxide film. Their presence leads to the formation of an electronically dead surface layer but also alters the band filling and the electron correlations in the thin films. These findings highlight that it is important to take into account surface apical oxygen or—mutatis mutandis—the specific oxygen configuration imposed by a capping layer to predict the behavior of ultrathin films of transition metal oxides near the single unit-cell limit.
KW  - transition metal oxides
KW  - correlated oxides
KW  - electronic phase transitions
KW  - photoelectron spectroscopy
KW  - thin films
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318914
SN  - 2199-160X
VL  - 8
IS  - 4
ER  - 
TY  - JOUR
A1  - Tappe, Beeke
A1  - Lauruschkat, Chris D.
A1  - Strobel, Lea
A1  - Pantaleón García, Jezreel
A1  - Kurzai, Oliver
A1  - Rebhan, Silke
A1  - Kraus, Sabrina
A1  - Pfeuffer-Jovic, Elena
A1  - Bussemer, Lydia
A1  - Possler, Lotte
A1  - Held, Matthias
A1  - Hünniger, Kerstin
A1  - Kniemeyer, Olaf
A1  - Schäuble, Sascha
A1  - Brakhage, Axel A.
A1  - Panagiotou, Gianni
A1  - White, P. Lewis
A1  - Einsele, Hermann
A1  - Löffler, Jürgen
A1  - Wurster, Sebastian
T1  - COVID-19 patients share common, corticosteroid-independent features of impaired host immunity to pathogenic molds
JF  - Frontiers in Immunology
N2  - Patients suffering from coronavirus disease-2019 (COVID-19) are susceptible to deadly secondary fungal infections such as COVID-19-associated pulmonary aspergillosis and COVID-19-associated mucormycosis. Despite this clinical observation, direct experimental evidence for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2)-driven alterations of antifungal immunity is scarce. Using an ex-vivo whole blood stimulation assay, we challenged blood from twelve COVID-19 patients with Aspergillus fumigatus and Rhizopus arrhizus antigens and studied the expression of activation, maturation, and exhaustion markers, as well as cytokine secretion. Compared to healthy controls, T-helper cells from COVID-19 patients displayed increased expression levels of the exhaustion marker PD-1 and weakened A. fumigatus- and R. arrhizus-induced activation. While baseline secretion of proinflammatory cytokines was massively elevated, whole blood from COVID-19 patients elicited diminished release of T-cellular (e.g., IFN-γ, IL-2) and innate immune cell-derived (e.g., CXCL9, CXCL10) cytokines in response to A. fumigatus and R. arrhizus antigens. Additionally, samples from COVID-19 patients showed deficient granulocyte activation by mold antigens and reduced fungal killing capacity of neutrophils. These features of weakened anti-mold immune responses were largely decoupled from COVID-19 severity, the time elapsed since diagnosis of COVID-19, and recent corticosteroid uptake, suggesting that impaired anti-mold defense is a common denominator of the underlying SARS-CoV-2 infection. Taken together, these results expand our understanding of the immune predisposition to post-viral mold infections and could inform future studies of immunotherapeutic strategies to prevent and treat fungal superinfections in COVID-19 patients.
KW  - COVID-19
KW  - immune impairment
KW  - T cells
KW  - granulocytes
KW  - Aspergillus
KW  - Rhizopus
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-283558
SN  - 1664-3224
VL  - 13
ER  -