65 research outputs found
Ground-based Raman-lidar for day and night measurements of water-vapor in the boundary layer
The solar-blind Raman-lidar based on a KrF laser (248 nm) developed at Lecceâs University (407 208 N, 187 68 E) is described. The lidar is currently used for day and night measurements of water vapor. The dependence of the measurement range of the lidar on the laser beam divergence is investigated and it is shown that the KrF laser beam divergence can be reduced by a factor A10 by using a quite
simple unstable cavity configuration. The maximum range which was limited to approximately 500 m for a A3 mrad divergence laser beam has increased up to 1200 m with a A0.3 mrad divergence laser beam since the field of view of the telescope was of 1 mrad. Water vapor profiles retrieved from lidar measurements under different operating conditions are presented. The effect of boundary-layer ozone absorption has also been investigated
Post-translational deregulation of YAP1 is genetically controlled in rat liver cancer and determines the fate and stem-like behavior of the human disease
Previous studies showed that YAP1 is over-expressed in hepatocellular carcinoma
(HCC). Here we observed higher expression of Yap1/Ctgf axis in dysplastic nodules and
HCC chemically-induced in F344 rats, genetically susceptible to hepatocarcinogenesis,
than in lesions induced in resistant BN rats. In BN rats, highest increase in Yap1-
tyr357, p73 phosphorylation and Caspase 3 cleavage occurred. In human HCCs with
poorer prognosis (< 3 years survival after partial liver resection, HCCP), levels of
YAP1, CTGF, 14â3â3, and TEAD proteins, and YAP1-14-3-3 and YAP1-TEAD complexes
were higher than in HCCs with better outcome (> 3 years survival; HCCB). In the
latter, higher levels of phosphorylated YAP1-ser127, YAP1-tyr357 and p73, YAP1
ubiquitination, and Caspase 3 cleavage occurred. Expression of stemness markers
NANOG, OCT-3/4, and CD133 were highest in HCCP and correlated with YAP1 and
YAP1-TEAD levels. In HepG2, Huh7, and Hep3B cells, forced YAP1 over-expression
led to stem cell markers expression and increased cell viability, whereas inhibition
of YAP1 expression by specific siRNA, or transfection of mutant YAP1 which does
not bind to TEAD, induced opposite alterations. These changes were associated, in
Huh7 cells transfected with YAP1 or YAP1 siRNA, with stimulation or inhibition of cell
migration and invasivity, respectively. Furthermore, transcriptome analysis showed
that YAP1 transfection in Huh7 cells induces over-expression of genes involved
in tumor stemness. In conclusion, Yap1 post-translational modifications favoring
its ubiquitination and apoptosis characterize HCC with better prognosis, whereas
conditions favoring the formation of YAP1-TEAD complexes are associated with
aggressiveness and acquisition of stemness features by HCC cells
Planck early results IX : XMM-Newton follow-up for validation of Planck cluster candidates
Peer reviewe
Planck Early Results XXVI: Detection with Planck and confirmation by XMM-Newton of PLCK G266.6-27.3, an exceptionally X-ray luminous and massive galaxy cluster at z~1
We present first results on PLCK G266.6-27.3, a galaxy cluster candidate
detected at a signal-to-noise ratio of 5 in the Planck All Sky survey. An
XMM-Newton validation observation has allowed us to confirm that the candidate
is a bona fide galaxy cluster. With these X-ray data we measure an accurate
redshift, z = 0.94 +/- 0.02, and estimate the cluster mass to be M_500 = (7.8
+/- 0.8)e+14 solar masses. PLCK G266.6-27.3 is an exceptional system: its
luminosity of L_X(0.5-2.0 keV)=(1.4 +/- 0.05)e+45 erg/s, equals that of the two
most luminous known clusters in the z > 0.5 universe, and it is one of the most
massive clusters at z~1. Moreover, unlike the majority of high-redshift
clusters, PLCK G266.6-27.3 appears to be highly relaxed. This observation
confirms Planck's capability of detecting high-redshift, high-mass clusters,
and opens the way to the systematic study of population evolution in the
exponential tail of the mass function.Comment: 6 pages, 3 figures; final version accepted for publication in A&A ;
minor changes in Sec.2.,3.2 and 4.1; Table 1: misprint on R500 error
corrected; abundance value adde
Planck early results. X. Statistical analysis of Sunyaev-Zeldovich scaling relations for X-ray galaxy clusters
All-sky data from the Planck survey and the Meta-Catalogue of X-ray detected Clusters of galaxies (MCXC) are combined to investigate the relationship between the thermal Sunyaev-Zeldovich (SZ) signal and X-ray luminosity. The sample comprises similar to 1600 X-ray clusters with redshifts up to similar to 1 and spans a wide range in X-ray luminosity. The SZ signal is extracted for each object individually, and the statistical significance of the measurement is maximised by averaging the SZ signal in bins of X-ray luminosity, total mass, or redshift. The SZ signal is detected at very high significance over more than two decades in X-ray luminosity (10(43) erg s(-1) less than or similar to L500E(z)(-7/3) less than or similar to 2 x 10(45) erg s(-1)). The relation between intrinsic SZ signal and X-ray luminosity is investigated and the measured SZ signal is compared to values predicted from X-ray data. Planck measurements and X-ray based predictions are found to be in excellent agreement over the whole explored luminosity range. No significant deviation from standard evolution of the scaling relations is detected. For the first time the intrinsic scatter in the scaling relation between SZ signal and X-ray luminosity is measured and found to be consistent with the one in the luminosity - mass relation from X-ray studies. There is no evidence of any deficit in SZ signal strength in Planck data relative to expectations from the X-ray properties of clusters, underlining the robustness and consistency of our overall view of intra-cluster medium properties
Planck early results. IX. XMM-Newton follow-up for validation of Planck cluster candidates
We present the XMM-Newton follow-up for confirmation of Planck cluster candidates. Twenty-five candidates have been observed to date using
snapshot (âŒ10 ks) exposures, ten as part of a pilot programme to sample a low range of signal-to-noise ratios (4 < S/N < 6), and a further 15 in a
programme to observe a sample of S/N > 5 candidates. The sensitivity and spatial resolution of XMM-Newton allows unambiguous discrimination
between clusters and false candidates. The 4 false candidates have S/N †4.1. A total of 21 candidates are confirmed as extended X-ray sources.
Seventeen are single clusters, the majority of which are found to have highly irregular and disturbed morphologies (about âŒ70%). The remaining
four sources are multiple systems, including the unexpected discovery of a supercluster at z = 0.45. For 20 sources we are able to derive a redshift
estimate from the X-ray Fe K line (albeit of variable quality). The new clusters span the redshift range 0.09 <⌠z <⌠0.54, with a median redshift
of z ⌠0.37. A first determination is made of their X-ray properties including the characteristic size, which is used to improve the estimate of
the SZ Compton parameter, Y500. The follow-up validation programme has helped to optimise the Planck candidate selection process. It has also
provided a preview of the X-ray properties of these newly-discovered clusters, allowing comparison with their SZ properties, and to the X-ray
and SZ properties of known clusters observed in the Planck survey. Our results suggest that Planck may have started to reveal a non-negligible
population of massive dynamically perturbed objects that is under-represented in X-ray surveys. However, despite their particular properties, these
new clusters appear to follow the Y500âYX relation established for X-ray selected objects, where YX is the product of the gas mass and temperature
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