127 research outputs found

    A NuSTAR view of powerful gamma-ray loud blazars

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    We observed with the NuSTAR satellite 3 blazars at z>2, detected in gamma-rays by Fermi/LAT and in the soft X-rays, but not yet observed above 10 keV. The flux and slope of their X-ray continuum, together with Fermi/LAT data allows us to estimate their total electromagnetic output and peak frequency. For some of them we can study the source in different states, and investigate the main cause of the observed different spectral energy distribution. We then collected all blazars at redshift greater than 2 observed by NuSTAR, and confirm that these hard and luminous X-ray blazars are among the most powerful persistent sources in the Universe. We confirm the relation between the jet power and the disk luminosity, extending it at the high energy end.Comment: 10 pages, 13 figures, accepted for publication in A&

    Acellular dermal matrix used in diabetic foot ulcers: Clinical outcomes supported by biochemical and histological analyses

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    Diabetic foot ulcer (DFU) is a diabetes complication which greatly impacts the patient’s quality of life, often leading to amputation of the affected limb unless there is a timely and adequate management of the patient. DFUs have a high economic impact for the national health system. Data have indeed shown that DFUs are a major cause of hospitalization for patients with diabetes. Based on that, DFUs represent a very important challenge for the national health system. Especially in developed countries diabetic patients are increasing at a very high rate and as expected, also the incidence of DFUs is increasing due to longevity of diabetic patients in the western population. Herein, the surgical approach focused on the targeted use of the acellular dermal matrix has been integrated with biochemical and morphological/histological analyses to obtain evidence-based information on the mechanisms underlying tissue regeneration. In this research report, the clinical results indicated decreased postoperative wound infection levels and a short healing time, with a sound regeneration of tissues. Here we demonstrate that the key biomarkers of wound healing process are activated at gene expression level and also synthesis of collagen I, collagen III and elastin is prompted and modulated within the 28-day period of observation. These analyses were run on five patients treated with Integra® sheet and five treated with the injectable matrix Integra® Flowable, for cavitary lesions. In fact, clinical evaluation of improved healing was, for the first time, supported by biochemical and histological analyses. For these reasons, the present work opens a new scenario in DFUs treatment and follow-up, laying the foundation for a tailored protocol towards complete healing in severe pathological conditions

    GASP XXXIV: Unfolding the thermal side of ram pressure stripping in the jellyfish galaxy JO201

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    X-ray studies of jellyfish galaxies play a crucial role in understanding the interactions between the interstellar medium (ISM) and the intracluster medium (ICM). In this paper, we focused on the jellyfish galaxy JO201. By combining archival Chandra observations, MUSE Hα\alpha cubes, and maps of the emission fraction of the diffuse ionised gas, we investigated both its high energy spectral properties and the spatial correlation between its X-ray and optical emissions. The X-ray emission of JO201 is provided by both the Compton thick AGN (LX0.510keV_{\text{X}}^{0.5-10 \text{keV}}=2.7\cdot1041^{41} erg s1^{-1}, not corrected for intrinsic absorption) and an extended component (LX0.510keV_{\text{X}}^{0.5-10 \, \text{keV}}\approx1.9-4.5\cdot1041^{41} erg s1^{-1}) produced by a warm plasma (kT\approx1 keV), whose luminosity is higher than expected from the observed star formation (LX_{\text{X}}\sim3.81040\cdot10^{40} erg s1^{-1}). The spectral analysis showed that the X-ray emission is consistent with the thermal cooling of hot plasma. These properties are similar to the ones found in other jellyfish galaxies showing extended X-ray emission. A point-to-point analysis revealed that this X-ray emission closely follows the ISM distribution, whereas CLOUDY simulations proved that the ionisation triggered by this warm plasma would be able to reproduce the [OI]/Hα\alpha excess observed in JO201. We conclude that the galactic X-ray emitting plasma is originated on the surface of the ISM as a result of the ICM-ISM interplay. This process would entail the cooling and accretion of the ICM onto the galaxy, which could additionally fuel the star formation, and the emergence of [OI]/Hα\alpha excess in the optical spectrum.Comment: 21 pages, 6 figures, 5 tables. Manuscript in press in Ap

    GASP XXXIV: Unfolding the thermal side of ram pressure stripping in the jellyfish galaxy JO201

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    X-ray studies of jellyfish galaxies play a crucial role in understanding the interactions between the interstellar medium (ISM) and the intracluster medium (ICM). In this paper, we focused on the jellyfish galaxy JO201. By combining archival Chandra observations, Multi Unit Spectroscopic Explorer Hα cubes, and maps of the emission fraction of the diffuse ionized gas, we investigated both its high-energy spectral properties and the spatial correlation between its X-ray and optical emissions. The X-ray emission of JO201 is provided by both the Compton-thick active galactic nucleus (L0.5X-10keV = 2.7 · 1041 erg s−1, not corrected for intrinsic absorption) and an extended component (L0.5X–10 keV » 1.9–4.5 · 1041 erg s−1) produced by a warm plasma (kT»1 keV), whose luminosity is higher than expected from the observed star formation (LX ~ 3.8 · 1040erg s−1). The spectral analysis showed that the X-ray emission is consistent with the thermal cooling of hot plasma. These properties are similar to the ones found in other jellyfish galaxies showing extended X-ray emission. A point-to-point analysis revealed that this X-ray emission closely follows the ISM distribution, whereas CLOUDY simulations proved that the ionization triggered by this warm plasma would be able to reproduce the [O I]/Hα excess observed in JO201. We conclude that the galactic X-ray emitting plasma originates on the surface of the ISM as a result of the ICM–ISM interplay. This process would entail the cooling and accretion of the ICM onto the galaxy, which could additionally fuel the star formation, and the emergence of [O I]/Hα excess in the optical spectrum

    CHEX-MATE: Constraining the origin of the scatter in galaxy cluster radial X-ray surface brightness profiles

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    We investigate the statistical properties and the origin of the scatter within the spatially resolved surface brightness profiles of the CHEXâ MATE sample, formed by 118 galaxy clusters selected via the SZ effect. These objects have been drawn from the Planck SZ catalogue and cover a wide range of masses, M500â =â [2â â â 15]à - 1014â Mâ , and redshift, zâ =â [0.05,â 0.6]. We derived the surface brightness and emission measure profiles and determined the statistical properties of the full sample and sub-samples according to their morphology, mass, and redshift. We found that there is a critical scale, Râ â ¼â 0.4R500, within which morphologically relaxed and disturbed object profiles diverge. The median of each sub-sample differs by a factor of â ¼10 at 0.05R500. There are no significant differences between mass- and redshift-selected sub-samples once proper scaling is applied. We compare CHEXâ MATE with a sample of 115 clusters drawn from the THE THREE HUNDRED suite of cosmological simulations. We found that simulated emission measure profiles are systematically steeper than those of observations. For the first time, the simulations were used to break down the components causing the scatter between the profiles. We investigated the behaviour of the scatter due to object-by-object variation. We found that the high scatter, approximately 110%, at R

    A retrofitting technique using steel grids for existing masonry panels: a numerical and analytical study

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    The current research focuses on a numerical and analytical study aimed at investigating the efficiency of a steel-based reinforcement system suitable for existing masonry walls. The application of such a retrofitting technique, which consists of glued thin steel grids applied on both faces of a masonry panel, is reversible, cheap and easy to be executed and appears to be suitable especially for buildings with concrete slab or inter-stories beams to which the steel elements could be anchored. The study is based on a reference experimental test carried out at the “Politehnica” University of Timisoara (Romania), within the European FP6 project PROHITECH. The reference test provided the application of a constant ver-tical compression and cyclic horizontal displacements to an unreinforced brick-cement mortar wall in full-scale (1500 × 1500 × 250mm), to which was conferred a double-fixed constraint condition. Based on the experimental evidences, a reference numerical model has been implemented in ABAQUS, by adopting a plastic-damage material and a macro-element approach for the masonry modelling. Hence, in order to determine a design crite-rion of the studied system, a comparison with the analytical formulations available in the current Italian and European codes for the unreinforced configuration is presented in this study. Then, a wide parametric study on the investigated retrofitting technique has been carried out by varying thickness and spacing of steel grid elements, as well as the geo-metrical ratio of the panel (height/length). On the basis of the numerical results, a capac-ity formulation has been proposed, which takes into account the steel distribution in the masonry panel. The obtained outcomes revealed that the strength increase achievable by adopting the studied reinforcement system could be compared to the efficiency of a rein-forced masonry wall of new construction and it is strongly influenced by the geometrical ratio of the wall, as well as the steel distribution

    Censimento del danno e delle tipologie costruttive nei Piani di Ricostruzione dei comuni del cratere sismico aquilano di Cocullo, Goriano Sicoli, Gagliano Aterno e San Demetrio ne’ Vestini

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    A seguito dell’evento sismico de L’Aquila del 6 Aprile 2009 si sono attivate procedure di rilevamento delle agibilità post-sisma delle costruzioni su larga scala. L’analisi speditiva dei fabbricati mediante la scheda di agibilità AeDES (Dipartimento di Protezione Civile) ha fornito un database di parametri sulla qualità strutturale e sul danno rilevato negli edifici esistenti molto utili allo sviluppo di nuove metodologie di analisi territoriale per la gestione del rischio sismico. Le azioni predisposte per la redazione dei Piani di Ricostruzione (PdR) hanno comportato lo studio delle caratteristiche degli edifici e degli effetti indotti dal sisma. Nella presente memoria si illustrano i risultati principali della fase di acquisizione dei dati e di analisi dell’edificato dei centri storici abruzzesi di Goriano Sicoli e Gagliano Aterno della Valle Subequana, di Cocullo nella Valle del Sagittario e di San Demetrio ne’ Vestini nella Valle dell’Aterno. I comuni, tutti appartenenti al cratere sismico, si collocano in contesti territoriali diversi per condizioni geologiche, orografiche e culturali, evidenziando ciascuno, proprie problematiche di ricostruzione e forti fragilità ambientali. Le attività di rilievo sintetizzate forniscono indicazioni sulle principali tipologie costruttive rilevate e consentono di caratterizzare la tipologia di danno strutturale che il recente sisma ha evidenziato
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