214 research outputs found
Variation in cold hardiness and carbohydrate concentration from dormancy induction to bud burst among provenances of three European oak species
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c myc deregulation is involved in melphalan resistance of multiple myeloma role of pdgf bb
Oncogenes are important regulators of cancer growth and progression and their action may be modulated by proteins of the growth factor family, such as angiogenic cytokines, known to be strongly involved in neoplastic evolution. Reciprocal interactions between oncogenes and angiogenic modulators may represent, in haematological neoplasms, including multiple myeloma (MM), a possible mechanism of drug resistance. The aim of this work is to investigate in vitro and in vivo whether or not c-myc deregulation is involved in the melphalan resistance elicited by myeloma patients and consequently to clarify the role of the angiogenic factor PDGF-BB in modulating c-myc protein expression. Fifty-one MM patients on chemotherapy with melphalan were analyzed for structural alterations of the c-myc gene, c-Myc protein expression, as well as for serum PDGF-BB release. For the in vitro study, two M14-derived established cell clones, differing for the c-Myc protein expression (c-Myc low -expressing or constitutively express..
Substructure and Scatter in the Mass-Temperature Relations of Simulated Clusters
Galaxy clusters exhibit regular scaling relations among their bulk
properties. These relations establish vital links between halo mass and cluster
observables. Precision cosmology studies that depend on these links benefit
from a better understanding of scatter in the mass-observable scaling
relations. Here we study the role of merger processes in introducing scatter
into the - relation, using a sample of 121 galaxy clusters
simulated with radiative cooling and supernova feedback, along with three
statistics previously proposed to measure X-ray surface brightness
substructure. These are the centroid variation (), the axial ratio (),
and the power ratios ( and ). We find that in this set of
simulated clusters, each substructure measure is correlated with a cluster's
departures and from the mean - relation, both for emission-weighted temperatures and for
spectroscopic-like temperatures , in the sense that clusters with
more substructure tend to be cooler at a given halo mass. In all cases, a
three-parameter fit to the - relation that includes substructure
information has less scatter than a two-parameter fit to the basic - relation.Comment: Accepted by ApJ, 10 pages, 10 figure
Non-parametric modeling of the intra-cluster gas using APEX-SZ bolometer imaging data
We demonstrate the usability of mm-wavelength imaging data obtained from the
APEX-SZ bolometer array to derive the radial temperature profile of the hot
intra-cluster gas out to radius r_500 and beyond. The goal is to study the
physical properties of the intra-cluster gas by using a non-parametric
de-projection method that is, aside from the assumption of spherical symmetry,
free from modeling bias. We use publicly available X-ray imaging data from the
XMM-Newton observatory and our Sunyaev-Zel'dovich Effect (SZE) imaging data
from the APEX-SZ experiment at 150 GHz to de-project the density and
temperature profiles for the relaxed cluster Abell 2204. We derive the gas
density, temperature and entropy profiles assuming spherical symmetry, and
obtain the total mass profile under the assumption of hydrostatic equilibrium.
For comparison with X-ray spectroscopic temperature models, a re-analysis of
the recent Chandra observation is done with the latest calibration updates.
Using the non-parametric modeling we demonstrate a decrease of gas temperature
in the cluster outskirts, and also measure the gas entropy profile. These
results are obtained for the first time independently of X-ray spectroscopy,
using SZE and X-ray imaging data. The contribution of the SZE systematic
uncertainties in measuring T_e at large radii is shown to be small compared to
the Chandra systematic spectroscopic errors. The upper limit on M_200 derived
from the non-parametric method is consistent with the NFW model prediction from
weak lensing analysis.Comment: Replaced with the published version; A&A 519, A29 (2010
Substructure of the galaxy clusters in the REXCESS sample: observed statistics and comparison to numerical simulations
We study the substructure statistics of a representative sample of galaxy
clusters by means of two currently popular substructure characterisation
methods, power ratios and centroid shifts. We use the 31 clusters from the
REXCESS sample, compiled from the southern ROSAT All-Sky cluster survey REFLEX
with a morphologically unbiased selection in X-ray luminosity and redshift, all
of which have been reobserved with XMM-Newton. We investigate the uncertainties
of the substructure parameters and examine the dependence of the results on
projection effects, finding that the uncertainties of the parameters can be
quite substantial. Thus while the quantification of the dynamical state of
individual clusters with these parameters should be treated with extreme
caution, these substructure measures provide powerful statistical tools to
characterise trends of properties in large cluster samples. The centre shift
parameter, w, is found to be more sensitive in general. For the REXCESS sample
neither the occurence of substructure nor the presence of cool cores depends on
cluster mass. There is a significant anti-correlation between the existence of
substantial substructure and cool cores. The simulated clusters show on average
larger substructure parameters than the observed clusters, a trend that is
traced to the fact that cool regions are more pronounced in the simulated
clusters, leading to stronger substructure measures in merging clusters and
clusters with offset cores. Moreover, the frequency of cool regions is higher
in the simulations than in the observations, implying that the description of
the physical processes shaping cluster formation in the simulations requires
further improvement.Comment: Mauscript submitted to Astronomy and Astrophysics, 20 figure
Discriminant analysis on small cell lung cancer and non-small cell lung cancer by means of NSE and CYFRA-21.1
A correct diagnosis of small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) is essential both for prognostic and therapeutic reasons. We used discriminant analysis as a method to optimize the discriminant power of serum tumour marker levels for differentiation between SCLC and NSCLC. A panel of serum markers, including neurone specific enolase (NSE), cytokeratin fragment antigen 21.1 (CYFRA-21.1), tissue polypeptide antigen (TPA) and carcinoembryonic antigen (CEA) was obtained in 50 consecutive NSCLC and 17 SCLC. Data were analysed by the BMDP statistical program after logarithmic transformation of marker levels. The variables selected were NSE and CYFRA-21.1. Considered together, they were able to give a 97% rate of correct classification. The formula generated (canonic variable, CV) was validated on a group of seven SCLC and 22 NSCLC patients. Only two errors occurred. We therefore conclude that the canonic variable tested, based on NSE and CYFRA-21.1, provides a good discrimination between the two types of lung cancer. The method is rapid, relatively inexpensive, and based on simple serum tests
Linee guida di prevenzione oncologica - Tabagismo
Linee guida sulla prevenzione oncologica predisposte dal Consiglio sanitario regionale toscano
Endothelin-1 Levels Are Increased in Sera and Lesional Skin Extracts of Psoriatic Patients and Correlate with Disease Severity
Endothelins (ETs), in addition to their systematical activities, exert important functions at the skin level, such as increase of keratinocyte proliferation, neo-angiogenesis and leukocyte chemotaxis, which are among the main characteristics of psoriasis. To assess a possible ET-1 involvement in plaque-type psoriasis, ET-1 determinations were carried out in 15 sera and 8 lesional and non-lesional biopsy skin extracts from psoriatic patients and in 15 sera and 5 biopsy skin extracts from healthy volunteers, sex- and age-matched, using commercially available ELISA kits. A statistical analysis of the results showed that ET-1 levels were increased in sera of psoriatic patients, as compared to normal subjects (p = 0.04). In addition, there was a significant correlation between both serum (r = 0.60, p = 0.02) and lesional skin (r = 0.80, p = 0.03) ET-1 values versus the Psoriasis Area and Severity Index scores. Significant increases of the lesional versus the non-lesional (p = 0.01) and versus the normal (p = 0.04) ET-1 skin extract values were observed, together with a significant correlation between lesional and non-lesional ET-1 skin levels (r = 0.79, p = 0.03). These findings were also confirmed at the mRNA level, using RT-PCR analysis, where increased ET-1 mRNA levels, densitometrically measured, were found in the lesional samples versus non-lesional and normal skin. Since interleukin-8 is involved in psoriasis and shares some biological properties with ET-1, we further evaluated the levels of this cytokine in skin extracts. The behaviour of interleukin-8 paralleled that of ET-1, and a significant correlation between these two molecules was observed in the lesional skin (r = 0.76, p = 0.05). Taken together, these data stress that, as previously described for interleukin-8, ET-1 may be involved in inflammatory processes associated with psoriasis
Strong lensing in the MareNostrum Universe: biases in the cluster lens population
Strong lensing is one of the most direct probes of the mass distribution in
the inner regions of galaxy clusters. It can be used to constrain the density
profiles and to measure the mass of the lenses. Moreover, the abundance of
strong lensing events can be used to constrain the structure formation and the
cosmological parameters through the so-called "arc-statistics" approach.
However, several issues related to the usage of strong lensing clusters in
cosmological applications are still controversial, leading to the suspect that
several biases may affect this very peculiar class of objects. With this study
we aim at better understanding the properties of galaxy clusters which can
potentially act as strong lenses. We do so by investigating the properties of a
large sample of galaxy clusters extracted from the N-body/hydrodynamical
simulation MareNostrum Universe. We explore the correlation between the cross
section for lensing and many properties of clusters, like the mass, the
three-dimensional and projected shapes, their concentrations, the X-ray
luminosity and the dynamical activity. We find that the probability of strong
alignments between the major axes of the lenses and the line of sight is a
growing function of the lensing cross section. In projection, the strong lenses
appear rounder within R200, but we find that their cores tend to be more
elliptical as the lensing cross section increases. We also find that the
cluster concentrations estimated from the projected density profiles tend to be
biased high. The X-ray luminosity of strong lensing clusters is higher than
that of normal lenses of similar mass and redshift. This is particular
significant for the least massive lenses. Finally, we find that the strongest
lenses generally exhibit an excess of kinetic energy within the virial radius,
indicating that they are more dynamically active than usual clusters.Comment: 22 pages, 18 figures, accepted for publication on A&
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