Multistatic SAR Imaging: First Results of a Four Phase Center Experiment with TerraSAR-X and TanDEM-X

Multichannel synthetic aperture radar (SAR) imaging offers the possibility to overcome the pulse repetition frequency (PRF) constraints inherent to single-channel SAR systems. The multichannel approach enables the acquisition of wide swathes with high azimuth resolution. Using a constellation or swarm of small satellites, a cost efficient, faulttolerant system can be envisaged. This paper describes the first results of a multistatic four phase center experiment conducted with TerraSAR-X and TanDEM-X. The experiment is intended to increase the know-how and demonstrate the capabilities for the design of future SAR systems. Key challenges are addressed, the experimental acquisition is described and an evaluation approach is presented. Finally, first results focusing on the azimuth ambiguity performance are shown

Time-varying business volatility, price setting, and the real effects of monetary policy

Does time-varying business volatility affect the price setting of firms and thus the transmission of monetary policy into the real economy? To address this question, we estimate from the firm-level micro data of the German IFO Business Climate Survey the impact of idiosyncratic volatility on the price setting behavior of firms. In a second step, we use a calibrated New Keynesian business cycle model to gauge the effects of time-varying volatility on the transmission of monetary policy to output. Our results are twofold. Heightened business volatility increases the probability of a price change, though the effect is small: the tripling of volatility during the recession of 08/09 caused the average quarterly likelihood of a price change to increase from 31.6% to 32.3%. Second, the effects of this increase in volatility on monetary policy are also small; the initial effect of a 25 basis point monetary policy shock to output declines from 0.347% to 0.341%

Extending teleoperated driving using a shared X-in-the-loop environment

The strong progress in modern vehicle system technology requires new methodological approaches for the development and validation of new vehicle systems. In particular, due to increasing automation, classical development methods and testing scenarios need to be evolved. Consequently, the publication focuses on an extension of teleoperated driving by the X-in-the-loop (XIL) approach. Within this framework, the classical concept based on VPN-LTE networking is analyzed and discussed at first. With this implementation, the remote control of a real vehicle is presented based on the use of a dynamic driving simulator. Especially for the development and validation of such concepts, an extension with the XIL methodology can improve this process. For this reason, the architecture of teleoperated driving is subsequently extended by networking with additional system components. The feasibility, the functionalities as well as the challenges that arise with such an extension based on the XIL methodology are shown.Within the scope of this study, the achieved transmission times for the control variables and for the video data stream are demonstrated. Based on different driving maneuvers, the achievable repeatability is discussed

Clean Donor Oxidation Enhances the H2 Evolution Activity of a Carbon Quantum Dot-Molecular Catalyst Photosystem.

Carbon quantum dots (CQDs) are new-generation light absorbers for photocatalytic H2 evolution in aqueous solution, but the performance of CQD-molecular catalyst systems is currently limited by the decomposition of the molecular component. Clean oxidation of the electron donor by donor recycling prevents the formation of destructive radical species and non-innocent oxidation products. This approach allowed a CQD-molecular nickel bis(diphosphine) photocatalyst system to reach a benchmark lifetime of more than 5 days and a record turnover number of 1094±61 molH2  (molNi )(-1) for a defined synthetic molecular nickel catalyst in purely aqueous solution under AM1.5G solar irradiation.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/anie.20160435

Cytochrome P450 Enzymes Involved in Metoprolol Metabolism and Use of Metoprolol as a CYP2D6 Phenotyping Probe Drug

Metoprolol is used for phenotyping of cytochrome P450 (CYP) 2D6, a CYP isoform considered not to be inducible by inducers of the CYP2C, CYP2B, and CYP3A families such as rifampicin. While assessing CYP2D6 activity under basal conditions and after pre-treatment with rifampicin in vivo, we surprisingly observed a drop in the metoprolol/α-OH-metoprolol clearance ratio, suggesting CYP2D6 induction. To study this problem, we performed in vitro investigations using HepaRG cells and primary human hepatocytes (before and after treatment with 20 μM rifampicin), human liver microsomes, and CYP3A4-overexpressing supersomes. While mRNA expression levels of CYP3A4 showed a 15- to 30-fold increase in both cell models, mRNA of CYP2D6 was not affected by rifampicin. 1′-OH-midazolam formation (reflecting CYP3A4 activity) increased by a factor of 5–8 in both cell models, while the formation of α-OH-metoprolol increased by a factor of 6 in HepaRG cells and of 1.4 in primary human hepatocytes. Inhibition studies using human liver microsomes showed that CYP3A4, 2B6, and 2C9 together contributed 19.0 ± 2.6% (mean ± 95%CI) to O-demethylation, 4.0 ± 0.7% to α-hydroxylation, and 7.6 ± 1.7% to N-dealkylation of metoprolol. In supersomes overexpressing CYP3A4, metoprolol was α-hydroxylated in a reaction inhibited by the CYP3A4-specific inhibitor ketoconazole, but not by the CYP2D6-specific inhibitor quinidine. We conclude that metoprolol is not exclusively metabolized by CYP2D6. CYP3A4, 2B6, and 2C9, which are inducible by rifampicin, contribute to α-hydroxylation, O-demethylation, and N-dealkylation of metoprolol. This contribution is larger after CYP induction by rifampicin but is too small to compromise the usability of metoprolol α-hydroxylation for CYP2D6 phenotyping