Efficient and stable CH3NH3PbI3-sensitized ZnO nanorod array solid-state solar cells

We report for the first time the use of a perovskite (CH3NH3PbI3) absorber in combination with ZnO nanorod arrays (NRAs) for solar cell applications. The perovskite material has a higher absorption coefficient than molecular dye sensitizers, gives better solar cell stability, and is therefore more suited as a sensitizer for ZnO NRAs. A solar cell efficiency of 5.0% was achieved under 1000 W m(-2) AM 1.5 G illumination for a solar cell with the structure: ZnO NRA/CH3NH3PbI3/spiro-MeOTAD/Ag. Moreover, the solar cell shows a good long-term stability. Using transient photocurrent and photovoltage measurements it was found that the electron transport time and lifetime vary with the ZnO nanorod length, a trend which is similar to that in dye-sensitized solar cells, DSCs, suggesting a similar charge transfer process in ZnO NRA/CH3NH3PbI3 solar cells as in conventional DSCs. Compared to CH3NH3PbI3/TiO2 solar cells, ZnO shows a lower performance due to more recombination losses

Weltkonjunktur und deutsche Konjunktur im Winter 2011

[Weltkonjunktur mit geringer Dynamik] Die Erholung der Weltkonjunktur ist im Jahr 2011 ins Stocken geraten. Zur Jahreswende steht die Weltwirtschaft unter dem Eindruck der Staatsschuldenkrise im Euroraum, Unsicherheiten über den Zustand des Finanzsektors, Unwägbarkeiten im Zusammenhang mit der finanzpolitischen Diskussion in den Vereinigten Staaten und einer überraschend schwachen Dynamik in den Schwellenländern. Für die Prognose ist angenommen, dass es noch einige Monate dauert, bis sich die Belastungen merklich verringern; eine Verschärfung der Vertrauenskrise ist jedoch nicht unterstellt. Unter diesen Voraussetzungen erwarten wir, dass die Produktion in den fortgeschrittenen Volkswirtschaften im Winterhalbjahr 2011/12 nur sehr schwach expandieren und danach nur langsam an Fahrt gewinnen wird. Die Wirtschaft in den Schwellenländern wird durch die schwache Ausweitung der Nachfrage in den fortgeschrittenen Volkswirtschaften im Prognosezeitraum zunächst weiter gebremst; sie wird aber dank wirtschaftspolitischer Anregungen im Verlauf des kommenden Jahres wieder auf einen Pfad rascherer Expansion einschwenken. Die Zunahme der Weltproduktion insgesamt dürfte sich im Jahr 2012 auf eine Rate von nur noch 3,4 Prozent verringern, nach voraussichtlich 3,8 Prozent im zu Ende gehenden Jahr. Für 2013 erwarten wir eine wieder etwas stärkere Zunahme des globalen Bruttoinlandsprodukts (4,0 Prozent). - [Deutsche Wirtschaft: Risiko einer Rezession bleibt hoch] Die Konjunktur in Deutschland gerät in eine Schwächephase. Die hohe Unsicherheit, die aus der Staatsschuldenkrise im Euroraum resultiert, wird sich zunehmend auf die Nachfrage der Haushalte und Unternehmen auswirken. Zudem dürften negative Impulse vom Außenhandel kommen, da die Produktion in wichtigen Handelspartnerländern im Euroraum zum Teil spürbar sinken dürfte. Jedoch wird die deutsche Wirtschaft nicht in eine Rezession geraten. Bereits im Sommerhalbjahr des kommenden Jahres dürfte die Konjunktur wieder an Fahrt gewinnen. Dies hängt aber wesentlich davon ab, ob sich – wie von uns in dieser Prognose angenommen – die Lage an den Finanzmärkten beruhigt und sich eine Lösung der Schuldenkrise im Euroraum abzeichnet. Insgesamt dürfte das Bruttoinlandsprodukt in den Jahren 2012 und 2013 um 0,5 bzw. 1,7 Prozent expandieren. Die konjunkturelle Schwäche dürfte keine größeren Bremsspuren am Arbeitsmarkt hinterlassen. Vielmehr wird die Arbeitslosigkeit im Durchschnitt beider Jahre voraussichtlich weiter sinken. --

The Effect of Scandium Ternary Intergrain Precipitates in Al-Containing High-Entropy Alloys

We investigate the effect of alloying with scandium on microstructure, high-temperature phase stability, electron transport, and mechanical properties of the Al2CoCrFeNi, Al0.5CoCrCuFeNi, and AlCoCrCu0.5FeNi high-entropy alloys. Out of the three model alloys, Al2CoCrFeNi adopts a disordered CsCl structure type. Both of the six-component alloys contain a mixture of body-centered cubic (bcc) and face centered cubic (fcc) phases. The comparison between in situ high-temperature powder diffraction data and ex situ data from heat-treated samples highlights the presence of a reversible bcc to fcc transition. The precipitation of a MgZn2-type intermetallic phase along grain boundaries following scandium addition affects all systems differently, but especially enhances the properties of Al2CoCrFeNi. It causes grain refinement; hardness and electrical conductivity increases (up to 20% and 14% respectively) and affects the CsCl-type → fcc equilibrium by moving the transformation to sensibly higher temperatures. The maximum dimensionless thermoelectric figure of merit (ZT) of 0.014 is reached for Al2CoCrFeNi alloyed with 0.3 wt.% Sc at 650 °C

Antibodies from convalescent plasma promote SARS-CoV-2 clearance in individuals with and without endogenous antibody response

BACKGROUNDNeutralizing antibodies are considered a key correlate of protection by current SARS-CoV-2 vaccines. The manner in which human infections respond to therapeutic SARS-CoV-2 antibodies, including convalescent plasma therapy, remains to be fully elucidated. METHODSWe conducted a proof-of-principle study of convalescent plasma therapy based on a phase I trial in 30 hospitalized COVID-19 patients with a median interval between onset of symptoms and first transfusion of 9 days (IQR, 7-11.8 days). Comprehensive longitudinal monitoring of the virological, serological, and disease status of recipients allowed deciphering of parameters on which plasma therapy efficacy depends. RESULTSIn this trial, convalescent plasma therapy was safe as evidenced by the absence of transfusion-related adverse events and low mortality (3.3%). Treatment with highly neutralizing plasma was significantly associated with faster virus clearance, as demonstrated by Kaplan-Meier analysis (P = 0.034) and confirmed in a parametric survival model including viral load and comorbidity (adjusted hazard ratio, 3.0; 95% CI, 1.1-8.1; P = 0.026). The onset of endogenous neutralization affected viral clearance, but even after adjustment for their pretransfusion endogenous neutralization status, recipients benefitted from plasma therapy with high neutralizing antibodies (hazard ratio, 3.5; 95% CI, 1.1-11; P = 0.034). CONCLUSIONOur data demonstrate a clear impact of exogenous antibody therapy on the rapid clearance of viremia before and after onset of the endogenous neutralizing response, and point beyond antibody-based interventions to critical laboratory parameters for improved evaluation of current and future SARS-CoV-2 therapies. TRIAL REGISTRATIONClinicalTrials.gov NCT04869072. FUNDINGThis study was funded via an Innovation Pool project by the University Hospital Zurich; the Swiss Red Cross Glückskette Corona Funding; Pandemiefonds of the UZH Foundation; and the Clinical Research Priority Program "Comprehensive Genomic Pathogen Detection" of the University of Zurich

The Solid Solution Series (GeTe)x(LiSbTe2)2 (1 ≤ x ≤ 11) and the Thermoelectric Properties of (GeTe)11(LiSbTe2)2

Exchanging one Ge2+ with two Li+ per formula unit in (GeTe)n(Sb2Te3) (n = 1, 2, 3, ...) eliminates cation vacancies, because it leads to an equal number of cations and anions. This substitution results in the solid solution (GeTe)x(LiSbTe2)2 (with x = n – 1, but n not necessarily an integer). For x 6, (GeTe)x(LiSbTe2)2 forms a GeTe-type structure that shows a phase transition to a cubic high-temperature phase at ca. 280 °C. The thermoelectric properties of (GeTe)11(LiSbTe2)2 have been investigated and show that this compound is a promising thermoelectric material with a ZT value of 1.0 at 450 °C. The high ZT value of the thermodynamically stable compound is caused by a low phononic contribution to the thermal conductivity; probably, Li acts as a “pseudo-vacancy”

HLA-B locus products resist degradation by the human cytomegalovirus immunoevasin US11.

To escape CD8+ T-cell immunity, human cytomegalovirus (HCMV) US11 redirects MHC-I for rapid ER-associated proteolytic degradation (ERAD). In humans, classical MHC-I molecules are encoded by the highly polymorphic HLA-A, -B and -C gene loci. While HLA-C resists US11 degradation, the specificity for HLA-A and HLA-B products has not been systematically studied. In this study we analyzed the MHC-I peptide ligands in HCMV-infected cells. A US11-dependent loss of HLA-A ligands was observed, but not of HLA-B. We revealed a general ability of HLA-B to assemble with β2m and exit from the ER in the presence of US11. Surprisingly, a low-complexity region between the signal peptide sequence and the Ig-like domain of US11, was necessary to form a stable interaction with assembled MHC-I and, moreover, this region was also responsible for changing the pool of HLA-B ligands. Our data suggest a two-pronged strategy by US11 to escape CD8+ T-cell immunity, firstly, by degrading HLA-A molecules, and secondly, by manipulating the HLA-B ligandome

Phase Transitions of Thermoelectric TAGS-85

The alloys (GeTe)x(AgSbTe2)100-x, commonly known as TAGS-x, are among the best performing p-type thermoelectric materials for the composition range 80 ≤ x ≤ 90 and in the temperature range 200-500 °C. They adopt a rhombohedrally distorted rocksalt structure at room temperature and are reported to undergo a reversible phase transition to a cubic structure at ∼250 °C. However, we show that, for the optimal x = 85 composition (TAGS-85), both the structural and thermoelectric properties are highly sensitive to the initial synthesis method employed. Single-phase rhombohedral samples exhibit the best thermoelectric properties but can only be obtained after an annealing step at 600 °C during initial cooling from the melt. Under faster cooling conditions, the samples obtained are inhomogeneous, containing multiple rhombohedral phases with a range of lattice parameters and exhibiting inferior thermoelectric properties. We also find that when the room-temperature rhombohedral phase is heated, an intermediate trigonal structure containing ordered cation vacancy layers is formed at ∼200 °C, driven by the spontaneous precipitation of argyrodite-type Ag8GeTe6 which alters the stoichiometry of the TAGS-85 matrix. The rhombohedral and trigonal phases of TAGS-85 coexist up to 380 °C, above which a single cubic phase is obtained and the Ag8GeTe6 precipitates redissolve into the matrix. On subsequent cooling a mixture of rhombohedral, trigonal, and Ag8GeTe6 phases is again obtained. Initially single-phase samples exhibit thermoelectric power factors of up to 0.0035 W m-1 K-2 at 500 °C, a value that is maintained on subsequent thermal cycling and which represents the highest power factor yet reported for undoped TAGS-85. Therefore, control over the structural homogeneity of TAGS-85 as demonstrated here is essential in order to optimize the thermoelectric performance.RST/Neutron and Positron Methods in Material

Multifactorial seroprofiling dissects the contribution of pre-existing human coronaviruses responses to SARS-CoV-2 immunity

Determination of SARS-CoV-2 antibody responses in the context of pre-existing immunity to circulating human coronavirus (HCoV) is critical for understanding protective immunity. Here we perform a multifactorial analysis of SARS-CoV-2 and HCoV antibody responses in pre-pandemic (N = 825) and SARS-CoV-2-infected donors (N = 389) using a custom-designed multiplex ABCORA assay. ABCORA seroprofiling, when combined with computational modeling, enables accurate definition of SARS-CoV-2 seroconversion and prediction of neutralization activity, and reveals intriguing interrelations with HCoV immunity. Specifically, higher HCoV antibody levels in SARS-CoV-2-negative donors suggest that pre-existing HCoV immunity may provide protection against SARS-CoV-2 acquisition. In those infected, higher HCoV activity is associated with elevated SARS-CoV-2 responses, indicating cross-stimulation. Most importantly, HCoV immunity may impact disease severity, as patients with high HCoV reactivity are less likely to require hospitalization. Collectively, our results suggest that HCoV immunity may promote rapid development of SARS-CoV-2-specific immunity, thereby underscoring the importance of exploring cross-protective responses for comprehensive coronavirus prevention