Non-stoichiometric oxide and metal interfaces and reactions

We have employed a combination of experimental surface science techniques and density functional calculations to study the reduction of TiO2(110) surfaces through the doping with submonolayer transition metals. We concentrate on the role of Ti adatoms in self doping of rutile and contrast the behaviour to that of Cr. DFT+U calculations enable identification of probable adsorption structures and their spectroscopic characteristics. Adsorption of both metals leads to a broken symmetry and an asymmetric charge transfer localised around the defect site of a mixed localised/delocalised character. Charge transfer creates defect states with Ti 3d character in the band gap at similar to 1-eV binding energy. Cr adsorption, however, leads to a very large shift in the valence-band edge to higher binding energy and the creation of Cr 3d states at 2.8-eV binding energy. Low-temperature oxidation lifts the Ti-derived band-gap states and modifies the intensity of the Cr features, indicative of a change of oxidation state from Cr3+ to Cr4+. Higher temperature processing leads to a loss of Cr from the surface region, indicative of its substitution into the bulk

Immunosuppression Has Long-Lasting Effects on Circulating Follicular Regulatory T Cells in Kidney Transplant Recipients

Background: FoxP3+ follicular regulatory T cells (Tfr) have been identified as the cell population controlling T follicular helper (Tfh) cells and B cells which, are both involved in effector immune responses against transplanted tissue. Methods: To understand the biology of Tfr cells in kidney transplant patients treated with tacrolimus and mycophenolate mofetil (MMF) combination immunosuppression, we measured circulating (c)Tfh and cTfr cells in peripheral blood by flow cytometry in n = 211 kidney transplant recipients. At the time of measurement patients were 5–7 years after transplantation. Of this cohort of patients, 23.2% (49/211) had been previously treated for rejection. Median time after anti-rejection therapy was 4.9 years (range 0.4–7 years). Age and gender matched healthy individuals served as controls. Results: While the absolute numbers of cTfh cells were comparable between kidney transplant recipients and healthy controls, the numbers of cTfr cells were 46% lower in immunosuppressed recipients (p < 0.001). More importantly, in transplanted patients, the ratio of cTfr to cTfh was decreased (median; 0.10 vs. 0.06), indicating a disruption of the balance between

Open data from the third observing run of LIGO, Virgo, KAGRA, and GEO

The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in 2019 April and lasting six months, O3b starting in 2019 November and lasting five months, and O3GK starting in 2020 April and lasting two weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main data set, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages

Influence of halogen substitution on optical property of mixed-valence gold halide investigated by photoacoustic spectroscopy

Influence of halogen substitution on the absorption spectra in the mixed-valence gold halide Cs$_2$Au$_2$X$_6$ (X = Cl, Br, and I) has been investigated by means of photoacoustic (PA) spectroscopy in the energy range of 1.0~3.5 eV at 300 K. The optical gap ($E_{\rm gap}$), which is assigned to the charge transfer from Au$^+$5dx$^2$-y$^2$ to Au$^{3+}$5dx$^2$-y$^2$ levels, shows a red shift from 1.61 eV for X = Cl to 1.18 eV for X = I. We have ascribed the reduced $E_{\rm gap}$-value to the suppression of the structural distortion of AuX$_4^-$

Thermal diffusivity of La0.6_0.6Sr0.4_0.4MnO3_3 thin film investigated by transient thermal grating technique

We investigate thermal diffusivity $\alpha$ of La$_{0.6}$Sr$_{0.4}$MnO$_3$ thin film by means of transient thermal grating technique. The transient thermal grating signal is analysised by Green's functions, and the thermal diffusivity $\alpha$ of La$_{0.6}$Sr$_{0.4}$MnO$_3$ film is determined to be 0.92 mm$^2$s$^{-1}$. Comparison with that (~1 mm2s-1) of the ceramic material, the smaller $\alpha$-value is ascribed to the mismatch of lattice for the film material

Thermal diffusivity of double perovskite Sr2_2FeMoO6_6 up to 450 K

Thermal diffusivity has been investigated in double perovskite Sr$_2$FeMoO$_6$ by means of transient surface grating in the temperature range of 300-450 K. The thermal diffusivity shows an appreciable decrease from 0.39 cm$^2$/s at 300 K to 0.37 cm$^2$/s at 360 K in the ferromagnetic phase, and then immediately decreases to 0.1 cm$^2$/s with further increasing temperature above the critical temperature Tc~380 K. Such an abruptly decrease of the thermal diffusivity has been ascribed to the structure change and hence the spin order-disorder transition