The contribution of faint AGN to the hard X-ray background

Hard X-ray selection is the most efficient way to discriminate between accretion-powered sources, such as AGN, from sources dominated by starlight. Hard X-rays are also less affected than other bands by obscuration. We have then carried out the BeppoSAX High Energy Large Area Survey (HELLAS) in the largely unexplored 5-10 keV band, finding 180 sources in ~50 deg^2 of sky with flux >5E-14 erg cm-2 s-1. After correction for the non uniform sky coverage this corresponds to resolving about 30 % of the hard Cosmic X-ray Background (XRB). Here we report on a first optical spectroscopic identification campaign, finding 12 AGN out of 14 X-ray error-boxes studied. Seven AGN show evidence for obscuration in X-ray and optical bands, a fraction higher than in previous ROSAT or ASCA-ROSAT surveys (at a 95-99 % and 90 % confidence level respectively), thus supporting the scenario in which a significant fraction of the XRB is made by obscured AGN.Comment: MNRAS, revised version after minor referee comment

New insights into the structure of early-type galaxies: the Photometric Plane at z~0.3

We study the Photometric Plane (PHP), namely the relation between the effective radius re, the mean surface brightness within that radius e, and the Sersic index n, in optical (R and I) and near-infrared (K) bands for a large sample of early-type galaxies (ETGs) in the rich cluster MS1008-1224 at z=0.306. The PHP relation has an intrinsic dispersion of ~32% in re, and turns out to be independent of waveband. This result is consistent with the fact that internal colour gradients of ETGs can have only a mild dependence on galaxy luminosity (mass). There is no evidence for a significant curvature in the PHP. We show that this can be explained if this relation origins from a systematic variation of the specific entropy of ETGs along the galaxy sequence, as was suggested from previous works. The intrinsic scatter of the PHP is significantly smaller than for other purely photometric relations, such as the Kormendy relation and the photometric Fundamental Plane, which is constructed by using colours in place of velocity dispersions. The scatter does not depend on the waveband and the residuals about the plane do not correlate with residuals of the colour-magnitude relation. Finally, we compare the coefficients of the PHP at z~0.3 with those of ETGs at z~0, showing that the PHP is a valuable tool to constrain the luminosity evolution of ETGs with redshift. The slopes of the PHP do not change significantly with redshift, while the zero-point is consistent with cosmological dimming of the surface brightness in an expanding universe plus the passive fading of galaxy stellar populations with a high formation redshift (z_f >1-2).Comment: 21 pages, 10 figures, MNRAS in pres

Clinical characteristics and outcome of patients with autoimmune hemolytic anemia (AIHA) uniformly defined as primary by a diagnostic work-up

Primary autoimmune hemolytic anemia (P-AIHA) is a relatively uncommon and hetereogeneous disease characterized by the destruction of red blood cells due to anti-erythrocyte autoantibodies (AeAbs) in the absence of an associated disease [1–3]. Secondary AHIA is frequently associated with lymphoproliferative diseases (LD) in particular, chronic lymphocytic leukemia, aggressive or indolent lymphomas, autoimmune disorders, malignancies other than lymphoid, and infections [1,2,4]. On the hypothetical assumption that in a significant proportion of cases defined as P-AIHA the clinical heterogeneity could be due to an ignored associated disease, we retrospectively analyzed the clinical characteristics and outcome of patients with a diagnosis of P-AIHA based on a diagnostic work-up aimed at excluding or identifying an associated disease. ..

The BeppoSAX High Energy Large Area Survey HELLAS, II: Number counts and X-ray spectral properties

The BeppoSAX High Energy Large Area Survey (HELLAS) has surveyed about 85 deg^2 of sky in the 5-10 keV band down to a flux of 4-5 10^-14 erg cm-2 s-1. The source surface density of 16.9+-6.4 deg$^{-2}$ at the survey limit corresponds to a resolved fraction of the 5-10 keV X-ray background (XRB) of the order of 20-30 %. Hardness ratios analysis indicates that the spectra of a substantial fraction of the HELLAS sources (at least one third) are harder than a alpha_E = 0.6 power law. This hardness may be due to large absorbing columns. The hardness ratio analysis also indicates that many HELLAS sources may have a spectrum more complex than a single absorbed power law. A soft component, superimposed to a strongly cut-off power law, is likely to be present in several sources.Comment: to appear in MNRA

po 259 inhibition of the hexosamine biosynthetic pathway by targeting pgm3 causes breast cancer growth arrest and apoptosis

Introduction Cancer aberrant N - and O -linked protein glycosylation, frequently resulting from an augmented flux through the Hexosamine Biosynthetic Pathway (HBP), play different roles in tumour progression. Recent studies reported an association between the tumorigenic potential, metastasis and chemoresistance of several type of breast cancer cells and tumours, among which the Triple Negative Breast Cancer (TNBC), and the alteration of their membrane glycans composition and ramification as well as of their level of protein O -Glc N Ac. However, the low specificity and toxicity of the existing HBP inhibitors prevented their use for cancer treatment. Material and methods In order to identify a novel inhibitor of HBP pathway and in particular of the PGM3 enzyme, we performed a virtual screening by using computational approaches. These approaches lead us to the identification of a lead compound. This compound, named FR054, has been synthetized and in vitro and in vivo tested by using several biophysical methods (NMR, LC/MS, HPLC) and biochemical assay (CETSA, ITDRF, FACS analysis) as well as tested in TNBC xenograft mice model. Results and discussions Here we report the preclinical evaluation of FR054, a novel inhibitor of the HBP enzyme PGM3, with a remarkable anti-breast cancer effect. In fact, FR054 induces in different breast cancer cells a dramatic decrease in cell proliferation and survival. In particular, in a model of Triple Negative Breast Cancer (TNBC) cells, MDA-MB-231, we show that these effects are correlated to FR054-dependent reduction of both N - and O -glycosylation level that cause also to a strong reduction of cancer cell adhesion and migration. Moreover we show that impaired survival of cancer cells upon FR054 treatment is associated with activation of the Unfolded Protein Response (UPR) and accumulation of intracellular ROS. Finally, we show that FR054 suppresses cancer growth in MDA-MB-231 xenograft mice. Conclusion Our data support the advantage of targeting HBP for therapeutic purpose and encourage further investigation about the use of this small-molecule as promising compound for breast cancer therapy