752 research outputs found
Androgen Receptor Functional Analyses by High Throughput Imaging: Determination of Ligand, Cell Cycle, and Mutation-Specific Effects
Understanding how androgen receptor (AR) function is modulated by exposure to steroids, growth factors or small molecules can have important mechanistic implications for AR-related disease therapies (e.g., prostate cancer, androgen insensitivity syndrome, AIS), and in the analysis of environmental endocrine disruptors.We report the development of a high throughput (HT) image-based assay that quantifies AR subcellular and subnuclear distribution, and transcriptional reporter gene activity on a cell-by-cell basis. Furthermore, simultaneous analysis of DNA content allowed determination of cell cycle position and permitted the analysis of cell cycle dependent changes in AR function in unsynchronized cell populations. Assay quality for EC50 coefficients of variation were 5–24%, with Z' values reaching 0.91. This was achieved by the selective analysis of cells expressing physiological levels of AR, important because minor over-expression resulted in elevated nuclear speckling and decreased transcriptional reporter gene activity. A small screen of AR-binding ligands, including known agonists, antagonists, and endocrine disruptors, demonstrated that nuclear translocation and nuclear “speckling” were linked with transcriptional output, and specific ligands were noted to differentially affect measurements for wild type versus mutant AR, suggesting differing mechanisms of action. HT imaging of patient-derived AIS mutations demonstrated a proof-of-principle personalized medicine approach to rapidly identify ligands capable of restoring multiple AR functions.HT imaging-based multiplex screening will provide a rapid, systems-level analysis of compounds/RNAi that may differentially affect wild type AR or clinically relevant AR mutations
Local lattice dynamics and isotope effect in yttrium diboride probed by extended x-ray absorption fine structure spectroscopy
The lattice vibration properties and the boron isotope effect have been studied in YB2 by using temperature-dependent extended x-ray absorption fine structure (EXAFS). The data show anomalous behavior of the Debye–Waller factor of the Y–B pair due to the superposition of an optical mode associated with the boron sublattice and an acoustic mode corresponding to the yttrium sublattice. We claim that the observed decoupling between metal and boron vibrations is responsible for the lower transition temperature compared to MgB2. The analysis of the boron isotope effect confirms also that the B–B vibration mode plays a key role in the electron–phonon coupling
Two years of flight of the Pamela experiment: results and perspectives
PAMELA is a satellite borne experiment designed to study with great accuracy
cosmic rays of galactic, solar, and trapped nature in a wide energy range
(protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the
study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50
MeV-270 GeV) and search for antinuclei with a precision of the order of
). The experiment, housed on board the Russian Resurs-DK1 satellite,
was launched on June, 2006 in a orbit with an
inclination of 70 degrees. In this work we describe the scientific objectives
and the performance of PAMELA in its first two years of operation. Data on
protons of trapped, secondary and galactic nature - as well as measurements of
the December 2006 Solar Particle Event - are also provided.Comment: To appear on J. Phys. Soc. Jpn. as part of the proceedings of the
International Workshop on Advances in Cosmic Ray Science March, 17-19, 2008
Waseda University, Shinjuku, Tokyo, Japa
Time dependence of the electron and positron components of the cosmic radiation measured by the PAMELA experiment between July 2006 and December 2015
Cosmic-ray electrons and positrons are a unique probe of the propagation of
cosmic rays as well as of the nature and distribution of particle sources in
our Galaxy. Recent measurements of these particles are challenging our basic
understanding of the mechanisms of production, acceleration and propagation of
cosmic rays. Particularly striking are the differences between the low energy
results collected by the space-borne PAMELA and AMS-02 experiments and older
measurements pointing to sign-charge dependence of the solar modulation of
cosmic-ray spectra. The PAMELA experiment has been measuring the time variation
of the positron and electron intensity at Earth from July 2006 to December 2015
covering the period for the minimum of solar cycle 23 (2006-2009) till the
middle of the maximum of solar cycle 24, through the polarity reversal of the
heliospheric magnetic field which took place between 2013 and 2014. The
positron to electron ratio measured in this time period clearly shows a
sign-charge dependence of the solar modulation introduced by particle drifts.
These results provide the first clear and continuous observation of how drift
effects on solar modulation have unfolded with time from solar minimum to solar
maximum and their dependence on the particle rigidity and the cyclic polarity
of the solar magnetic field.Comment: 11 pages, 2 figure
A new measurement of the antiproton-to-proton flux ratio up to 100 GeV in the cosmic radiation
A new measurement of the cosmic ray antiproton-to-proton flux ratio between 1
and 100 GeV is presented. The results were obtained with the PAMELA experiment,
which was launched into low-earth orbit on-board the Resurs-DK1 satellite on
June 15th 2006. During 500 days of data collection a total of about 1000
antiprotons have been identified, including 100 above an energy of 20 GeV. The
high-energy results are a ten-fold improvement in statistics with respect to
all previously published data. The data follow the trend expected from
secondary production calculations and significantly constrain contributions
from exotic sources, e.g. dark matter particle annihilations.Comment: 10 pages, 4 figures, 1 tabl
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