14 research outputs found
Demystifying an unidentified EGRET source by VHE gamma-ray observations
In a novel approach in observational high-energy gamma-ray astronomy,
observations carried out by imaging atmospheric Cherenkov telescopes provide
necessary templates to pinpoint the nature of intriguing, yet unidentified
EGRET gamma-ray sources. Using GeV-photons detected by CGRO EGRET and taking
advantage of high spatial resolution images from H.E.S.S. observations, we were
able to shed new light on the EGRET observed gamma-ray emission in the
Kookaburra complex, whose previous coverage in the literature is somewhat
contradictory. 3EGJ1420-6038 very likely accounts for two GeV gamma-ray sources
(E>1 GeV), both in positional coincidence with the recently reported pulsar
wind nebulae (PWN) by HESS in the Kookaburra/Rabbit complex. PWN associations
at VHE energies, supported by accumulating evidence from observations in the
radio and X-ray band, are indicative for the PSR/plerionic origin of spatially
coincident, but still unidentified Galactic gamma-ray sources from EGRET. This
not only supports the already suggested connection between variable, but
unidentified low-latitude gamma-ray sources with pulsar wind nebulae
(3EGJ1420-6038 has been suggested as PWN candidate previoulsy), it also
documents the ability of resolving apparently confused EGRET sources by
connecting the GeV emission as measured from a large-aperture space-based
gamma-ray instrument with narrow field-of-view but superior spatial resolution
observations by ground-based atmospheric Cherenkov telescopes, a very promising
identification technique for achieving convincing individual source
identifications in the era of GLAST-LAT.Comment: 4 pages, 5 figures, Accepted for publication in Astrophysics and
Space Science, Proc. of "The Multi-Messenger Approach to High-Energy
Gamma-ray Sources (Third Workshop on the Nature of Unidentified High-Energy
Sources)", Barcelona, July 4-7, 2006, one typo correcte
Potential Prognostic and Diagnostic Application of a Novel Monoclonal Antibody Against Keratinocyte Growth Factor Receptor
Fibroblast Growth Factor Receptor-2 Expression in Thyroid Tumor Progression: Potential Diagnostic Application
Fibroblast growth factor receptor-2 (FGFR-2) plays an important role in tumorigenesis. In thyroid cancer it has been observed a FGFR-2 down-modulation, but the role of this receptor has not been yet clarified. Therefore, we decided to examine the expression of both FGFR-2 isoform, FGFR-2-IIIb and FGFR-2-IIIc, in different histological thyroid variants such as hyperplasia, follicular adenoma and papillary carcinoma. Immunohistochemistry and quantitative Real-Time PCR analyses were performed on samples of hyperplasia, follicular adenoma and papillary carcinoma, compared with normal thyroid tissue. Thyroid hyperplasia did not show statistically significant reduction in FGFR-2 protein and mRNA levels. Interestingly, in both follicular adenoma and papillary carcinoma samples we observed a strongly reduced expression of both FGFR-2 isoforms. We speculate that FGFR-2 down-modulation might be an early event in thyroid carcinogenesis. Furthermore, we suggest the potential use of FGFR-2 as an early marker for thyroid cancer diagnosis