Localization and broadband follow-up of the gravitational-wave transient GW150914

A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline, and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams

SI, BE, AND C ION IMPLANTATION IN GAAS0.93P0.07

The activation efficiencies of implanted Si, Be, and C in GaAs0.93P0.07 have been measured in the annealing range 650-950 degrees C. Be provides much higher sheet hole densities than C, even when the latter is coimplanted with Ar to enhance the electrical activity. The maximum activation efficiency of Be is similar to 60% at a close of 5X10(14) cm(2) whereas that of C is an order of magnitude lower, Si produces donor activation percentages up to similar to 20% under optimized annealing conditions. Capless proximity annealing is adequate for surface preservation up to similar to 950 degrees C as measured by scanning electron microscopy and atomic force microscopy. Photoluminescence measurements provide evidence that nonradiative, damage-related point defects remain in the GaAsP even after annealing or 950 degrees C. (C) 1996 American Institute of Physics.open11sciescopu

Applying the CiPA approach to evaluate cardiac proarrhythmia risk of some antimalarials used off‐label in the first wave of COVID‐19

We applied a set of in silico and in vitro assays, compliant with the CiPA (Comprehensive In Vitro Proarrhythmia Assay) paradigm, to assess the risk of chloroquine or hydroxychloroquine‐mediated QT prolongation and Torsades de Pointes (TdP), alone and combined with erythromycin and azithromycin, drugs repurposed during the first wave of COVID‐19. Each drug or drug combination was tested in patch clamp assays on 7 cardiac ion channels, in in silico models of human ventricular electrophysiology (Virtual Assay®) using control (healthy) or high‐risk cell populations, and in human induced pluripotent stem cell (hiPSC)‐derived cardiomyocytes. In each assay, concentration‐response curves encompassing and exceeding therapeutic free plasma levels were generated. Both chloroquine and hydroxychloroquine showed blocking activity against some potassium, sodium and calcium currents. Chloroquine and hydroxychloroquine inhibited IKr (IC50: 1µM and 3‐7µM, respectively) and IK1 currents (IC50: 5 and 44µM, respectively). When combining hydroxychloroquine with azithromycin, no synergistic effects were observed. The two macrolides had no or very weak effects on the ion currents (IC50>300‐1000µM). Using Virtual Assay®, both antimalarials affected several TdP indicators, chloroquine being more potent than hydroxychloroquine. Effects were more pronounced in the high‐risk cell population. In hiPSC‐derived cardiomyocytes, all drugs showed early‐after‐depolarizations, except azithromycin. Combining chloroquine or hydroxychloroquine with a macrolide did not aggravate their effects. In conclusion, our integrated nonclinical CiPA dataset confirmed that, at therapeutic plasma concentrations relevant for malaria or off‐label use in COVID‐19, chloroquine and hydroxychloroquine use is associated with a proarrhythmia risk, which is higher in populations carrying predisposing factors but not worsened with macrolide combination