4,961 research outputs found
Signal transducer and activator of transcription-1 localizes to the mitochondria and modulates mitophagy
The signal transducer and activator of transcription (STAT) proteins are latent transcription factors that have been shown to be involved in cell proliferation, development, apoptosis, and autophagy. STAT proteins undergo activation by phosphorylation at tyrosine 701 and serine 727 where they translocate to the nucleus to regulate gene expression. STAT1 has been shown to be involved in promoting apoptotic cell death in response to cardiac ischemia/reperfusion and has recently been shown by our laboratory to be involved in negatively regulating autophagy. These processes are thought to promote cell death and restrict cell survival leading to the generation of an infarct. Here we present data that shows STAT1 localizes to the mitochondria and co-immunoprecipitates with LC3. Furthermore, electron microscopy studies also reveal mitochondria from ex vivo I/R treated hearts of STAT1KO mice contained within a double membrane autophagosome indicating that STAT1 may be involved in negatively regulating mitophagy. This is the first description of STAT1 being localized to the mitochondria and also having a role in mitophagy
Radiative Tau Decays with One Pseudoscalar Meson
We have calculated the decay . We present
the photon energy spectrum, the meson-photon invariant mass spectrum and the
integrated rate as a function of a photon energy cut or an invariant mass cut.
Both the internal bremsstrahlung and the structure dependent radiation have
been taken into account. To this aim we have parametrized the form factors
and , which determine the structure dependent radiation. Observables
especially suited for the measurement of the structure dependent form factors
are found and implications on the width of the discussed.Comment: p.20, TTP93-1, LaTe
Radial Velocity along the Voyager 1 Trajectory: The Effect of Solar Cycle
As Voyager 1 and Voyager 2 are approaching the heliopause (HP)—the boundary between the solar wind (SW) and the local interstellar medium (LISM)—we expect new, unknown features of the heliospheric interface to be revealed. A seeming puzzle reported recently by Krimigis et al. concerns the unusually low, even negative, radial velocity components derived from the energetic ion distribution. Steady-state plasma models of the inner heliosheath (IHS) show that the radial velocity should not be equal to zero even at the surface of the HP. Here we demonstrate that the velocity distributions observed by Voyager 1 are consistent with time-dependent simulations of the SW-LISM interaction. In this Letter, we analyze the results from a numerical model of the large-scale heliosphere that includes solar cycle effects. Our simulations show that prolonged periods of low to negative radial velocity can exist in the IHS at substantial distances from the HP. It is also shown that Voyager 1 was more likely to observe such regions than Voyager 2
Hadron structure in tau -> KKpi nu_tau decays
We analyse the hadronization structure of both vector and axial-vector
currents leading to tau -> KKpi nu_tau decays. At leading order in the 1/Nc
expansion, and considering only the contribution of the lightest resonances, we
work out, within the framework of the resonance chiral Lagrangian, the
structure of the local vertices involved in those processes. The couplings in
the resonance theory are constrained by imposing the asymptotic behaviour of
vector and axial-vector spectral functions ruled by QCD. In this way we predict
the hadron spectra and conclude that, contrarily to previous assertions, the
vector contribution dominates by far over the axial-vector one in all KKpi
charge channels.Comment: 32 pages, 7 figure
Three-dimensional Quantum-size Effect In Chemically Deposited Cadmium Selenide Films
Optical band gaps, Eg, up to 0.5 eV higher than in single-crystal samples, are observed for chemically deposited films of CdSe and explained in terms of a quantum-size effect, whereby the electrons are localized in individual crystallites. The increase in Eg depends strongly on deposition temperature, with the greatest increase obtained at the lowest temperature. Annealing at temperatures above the deposition temperature causes a decrease in Eg; this decrease is stronger at higher annealing temperature. Structural studies of the as-deposited layers showed them to be composed of microcrystalline, cubic CdSe, and electron microscopy resolved them into individual crystallites of typically 4080-A diameter, depending on deposition temperature. This is the first example reported of a three-dimensional quantum-size effect in a film. © 1987 The American Physical Society.3684215422
Ground-simulation investigations of VTOL airworthiness criteria for terminal-area operations
Several ground-based simulation experiments undertaken to investigate concerns related to tilt-rotor aircraft airworthiness were conducted. The experiments were conducted on the National Aeronautics and Space Administration (NASA) Ames Research Center's Vertical Motion Simulator, which permits simulation of a wide variety of aircraft with a high degree of fidelity of motion cueing. Variations in conversion/deceleration profile, type of augmentation or automation, level of display assistance, and meteorological conditions were considered in the course of the experiments. Certification pilots from the Federal Aviation Administration (FAA) and the Civil Aviation Authority (CAA) participated, in addition to NASA research pilots. The setup of these experiments on the simulator is summarized, and some of the results highlighted
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