63 research outputs found
The 2003 eclipse of EE Cep is coming. A review of past eclipses
EE Cep is an eclipsing binary with a period of 5.6 years. The next eclipse
will occur soon, in May-June 2003, and all available past eclipses were
collected and briefly analysed. EE Cep shows very large changes of the shape
and the depth of minima during different eclipses, however it is possible to
single out some persistent features. The analysis suggests that the eclipsing
body should be a long object surrounded by an extended semi-transparent
envelope. As an explanation, a model of a precessing optically thick disc,
inclined to the plane of the binary orbit, is invoked. The changes of its
spatial orientation, which is defined by the inclination of the disc and the
tilt, induced most probably by precession of the disc spin axis with a period
of about 50 years, produce strange photometric behaviour of this star. The
H_alpha emission, and possibly the NaI absorptions, show significant changes
during several months outside of the eclipse phase.Comment: 7 pages, 7 figures, LaTeX2e, accepted by A&
Taming the Invisible Monster: System Parameter Constraints for Epsilon Aurigae from the Far-Ultraviolet to the Mid-Infrared
We have assembled new Spitzer Space Telescope Infrared Array Camera
observations of the mysterious binary star Epsilon Aurigae, along with archival
far-ultraviolet to mid-infrared data, to form an unprecedented spectral energy
distribution spanning three orders of magnitude in wavelength from 0.1 microns
to 100 microns. The observed spectral energy distribution can be reproduced
using a three component model consisting of a 2.2+0.9/-0.8 Msun F type
post-asymptotic giant branch star, and a 5.9+/-0.8 Msun B5+/-1 type main
sequence star that is surrounded by a geometrically thick, but partially
transparent, disk of gas and dust. At the nominal HIPPARCOS parallax distance
of 625 pc, the model normalization yields a radius of 135+/-5 Rsun for the F
star, consistent with published interferometric observations. The dusty disk is
constrained to be viewed at an inclination of i > 87 deg, and has effective
temperature of 550+/-50 K with an outer radius of 3.8 AU and a thickness of
0.95 AU. The dust content of the disk must be largely confined to grains larger
than ~10 microns in order to produce the observed gray optical-infrared
eclipses and the lack of broad dust emission features in the archival Spitzer
mid-infrared spectra. The total mass of the disk, even considering a potential
gaseous contribution in addition to the dust that produces the observed
infrared excess, is << 1 Msun. We discuss evolutionary scenarios for this
system that could lead to the current status of the stellar components and
suggests possibilities for its future evolution, as well as potential
observational tests of our model.Comment: 13 pages, 3 figures. Accepted for publication in The Astrophysical
Journal
Constitutive activation of the EGFR-STAT1 axis increases proliferation of meningioma tumor cells.
Background: Meningiomas are the most frequent primary brain tumors of the central nervous system. The standard of treatment is surgery and radiotherapy, but effective pharmacological options are not available yet. The well-characterized genetic background stratifies these tumors in several subgroups, thus increasing diversification. We identified epidermal growth factor receptor-signal transducer and activator of transcription 1 (EGFR-STAT1) overexpression and activation as a common identifier of these tumors. Methods: We analyzed STAT1 overexpression and phosphorylation in 131 meningiomas of different grades and locations by utilizing several techniques, including Western blots, qPCR, and immunocytochemistry. We also silenced and overexpressed wild-type and mutant forms of the gene to assess its biological function and its network. Results were further validated by drug testing. Results: STAT1 was found widely overexpressed in meningioma but not in the corresponding healthy controls. The protein showed constitutive phosphorylation not dependent on the JAK-STAT pathway. STAT1 knockdown resulted in a significant reduction of cellular proliferation and deactivation of AKT and ERK1/2. STAT1 is known to be activated by EGFR, so we investigated the tyrosine kinase and found that EGFR was also constitutively phosphorylated in meningioma and was responsible for the aberrant phosphorylation of STAT1. The pharmaceutical inhibition of EGFR caused a significant reduction in cellular proliferation and of overall levels of cyclin D1, pAKT, and pERK1/2. Conclusions: STAT1-EGFR-dependent constitutive phosphorylation is responsible for a positive feedback loop that causes its own overexpression and consequently an increased proliferation of the tumor cells. These findings provide the rationale for further studies aiming to identify effective therapeutic options in meningioma
Structure and expression of the human globin genes and murine histocompatibility antigen genes
PO-511 High miR-9 levels represent a novel prognostic biomarker to predict development of malignant meningioma
PROTEOME AND PHOSPHOPROTEOME ANALYSIS IDENTIFIES STAT1 AS A NOVEL TARGET IN DIFFERENT GRADE MENINGIOMAS
The PROVENT-C19 registry: A study protocol for international multicenter SIAARTI registry on the use of prone positioning in mechanically ventilated patients with COVID-19 ARDS
Background The worldwide use of prone position (PP) for invasively ventilated patients with COVID-19 is progressively increasing from the first pandemic wave in everyday clinical practice. Among the suggested treatments for the management of ARDS patients, PP was recommended in the Surviving Sepsis Campaign COVID-19 guidelines as an adjuvant therapy for improving ventilation. In patients with severe classical ARDS, some authors reported that early application of prolonged PP sessions significantly decreases 28-day and 90-day mortality. Methods and analysis Since January 2021, the COVID19 Veneto ICU Network research group has developed and implemented nationally and internationally the "PROVENT-C19 Registry", endorsed by the Italian Society of Anesthesia Analgesia Resuscitation and Intensive Care. . .'(SIAARTI). The PROVENT-C19 Registry wishes to describe 1. The real clinical practice on the use of PP in COVID-19 patients during the pandemic at a National and International level; and 2. Potential baseline and clinical characteristics that identify subpopulations of invasively ventilated patients with COVID-19 that may improve daily from PP therapy. This web-based registry will provide relevant information on how the database research tools may improve our daily clinical practice. Conclusions This multicenter, prospective registry is the first to identify and characterize the role of PP on clinical outcome in COVID-19 patients. In recent years, data emerging from large registries have been increasingly used to provide real-world evidence on the effectiveness, quality, and safety of a clinical intervention. Indeed observation-based registries could be effective tools aimed at identifying specific clusters of patients within a large study population with widely heterogeneous clinical characteristics. Copyright
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