2,564 research outputs found

    The LAUE project for broadband gamma-ray focusing lenses

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    We present the LAUE project devoted to develop an advanced technology for building a high focal length Laue lens for soft gamma--ray astronomy (80-600 keV). The final goal is to develop a focusing optics that can improve the current sensitivity in the above energy band by 2 orders of magnitude.Comment: 7 pages, 6 figures, presented at the SPIE conference on "Optics for EUV, X-ray, and Gamma-ray Astronomy". To be published in the Proceedings of SPIE, vol.8147, 201

    Experimental study on the in-plane response of adobe masonry wallets strengthened with textile reinforced matrix systems

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    Seismic strengthening of existing adobe masonry (AM) buildings has been recognized as a critical issue due to the dramatic consequences of recent seismic events occurred especially in developing countries, where a great part of the population lives in those constructions. Previous studies investigated the effectiveness of different retrofitting techniques by means of experimental programs consisting of either dynamic or static tests on reduced- or full-scale specimens, representing partial or complete AM dwellings. In this study, the output of diagonal compression tests on adobe masonry panels before and after external strengthening are presented. Three series of specimens were tested, namely, unreinforced and strengthened wallets with textile reinforced matrix (TRM) systems made of either hemp or glass meshes. Those tests benefitted from the characterization of the mud mortar that was used for both masonry joints and matrix, representing typical characteristics of existing Italian AM buildings. Main testing outcomes obtained for the AM wallets, particularly in terms of observed damage and response curves, are presented and discussed. In the end, the effectiveness of the applied TRM systems in the improvement of shear strength and ductility capacity is assessed

    Experimental in-plane lateral response of a full-scale adobe masonry wall with opening

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    A large amount of world population lives nowadays in earthen buildings, often constructed only based on construction practice and within earthquake-prone regions. In the recent history, several strong earthquakes had dramatic consequences on these structures, highlighting their significant seismic vulnerability due to multiple reasons, such as poor mechanical properties, poor detailing, and large inertia mass. Several aspects of seismic performance of existing earthen constructions need to be investigated through full-scale experimental testing. In this regard, the present study aims at contributing to the investigation by testing a full-scale adobe masonry wall with a central door-type opening under in-plane lateral loading with cyclic fashion. The mechanical behaviour of materials, specimen's design, loading protocol and instrumentation setup are described. The experimental response curves, observed damage evolution and failure mode are discussed, especially focusing on dissipation capacity of the wall

    Convergence in measure under Finite Additivity

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    We investigate the possibility of replacing the topology of convergence in probability with convergence in L1L^1. A characterization of continuous linear functionals on the space of measurable functions is also obtained

    Post-operative morbidity following pancreatic duct occlusion without anastomosis after pancreaticoduodenectomy: a systematic review and meta-analysis

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    Background: Pancreatic duct occlusion (PDO) without anastomosis is a technique proposed to mitigate the clinical consequences of postoperative pancreatic fistulas (POPF) after pancreaticoduodenectomy. The aim of this study was to appraise the morbidity following PDO through a systematic review and meta-analysis. Methods: A systematic search of MEDLINE, Embase, and Web Of Science identified studies reporting outcomes of PDO following pancreaticoduodenectomy. Pooled prevalence rates of postoperative complications and mortality were computed using random-effect modeling. Meta-regression analyses were performed to examine the impact of moderators on the overall estimates. Results: Sixteen studies involving 1000 patients were included. Pooled postoperative mortality was 2.7%. A POPF was reported in 29.7% of the patients. Clinically relevant POPFs occurred in 13.5% of the patients, while intra-abdominal abscess and haemorrhages occurred in 6.7% and 5.5% of the patients, respectively. Re-operation was necessary in 7.6% of the patients. Postoperatively new onset diabetes occurred in 15.8% of patients, more frequently after the use of chemical substances for PDO (p = 0.003). Conclusions: PDO is associated with significant morbidity including new onset of post-operative diabetes. The risk of new onset post-operative diabetes is associated with the use of chemical substance for PDO. Further evidence is needed to evaluate the potential benefits of PDO in patients at high risk of POPF

    Development status of the LAUE project

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    We present the status of LAUE, a project supported by the Italian Space Agency (ASI), and devoted to develop Laue lenses with long focal length (up to 100 meters), for hard X--/soft gamma--ray astronomy (80-600 keV). Thanks to their focusing capability, the design goal is to improve the sensitivity of the current instrumention in the above energy band by 2 orders of magnitude, down to a few times 10‚ąí810^{-8} photons/(cm2^2 s keV).Comment: 9 pages, 9 figures, presented at the Space Telescopes and Instrumentation Symposium in Amsterdam, 2012: Ultraviolet to Gamma Ray Conference. Published in the Proceedings of the SPIE, Volume 8443, id. 84430B-84430B-9 (2012

    Scientific prospects in soft gamma-ray astronomy enabled by the LAUE project

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    This paper summarizes the development of a successful project, LAUE, supported by the Italian Space Agency (ASI) and devoted to the development of long focal length (up to 100 m) Laue lenses for hard X--/soft gamma--ray astronomy (80-600 keV). The apparatus is ready and the assembling of a prototype lens petal is ongoing. The great achievement of this project is the use of bent crystals. From measurements obtained on single crystals and from simulations, we have estimated the expected Point Spread Function and thus the sensitivity of a lens made of petals. The expected sensitivity is a few √ó10‚ąí8\times10^{-8} photons cm‚ąí2^{-2} s‚ąí1^{-1} keV‚ąí1^{-1}. We discuss a number of open astrophysical questions that can settled with such an instrument aboard a free-flying satellite.Comment: 17 pages, 18 figures, published in Proceedings of the SPIE, Volume 8861, id. 886106 17 pp. (2013

    Portal venous gas after a failed endoscopic retrograde cholangiopancreatography attempt in a patient with a large hepatocellular carcinoma: A case report

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    The cause of hepatic portal vein gas (HPVG) is variable. Good knowledge of the possible causes, combined with the clinical assessment of the patient and a good quality imaging, is required to correctly identify the underlying cause of HPVG and to best predict the prognosis

    Adenoviral gene transfer of PLD1-D4 enhances insulin sensitivity in mice by disrupting phospholipase D1 interaction with PED/PEA-15.

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    Over-expression of phosphoprotein enriched in diabetes/phosphoprotein enriched in astrocytes (PED/PEA-15) causes insulin resistance by interacting with the D4 domain of phospholipase D1 (PLD1). Indeed, the disruption of this association restores insulin sensitivity in cultured cells over-expressing PED/PEA-15. Whether the displacement of PLD1 from PED/PEA-15 improves insulin sensitivity in vivo has not been explored yet. In this work we show that treatment with a recombinant adenoviral vector containing the human D4 cDNA (Ad-D4) restores normal glucose homeostasis in transgenic mice overexpressing PED/PEA-15 (Tg ped/pea-15) by improving both insulin sensitivity and secretion. In skeletal muscle of these mice, D4 over-expression inhibited PED/PEA-15-PLD1 interaction, decreased Protein Kinase C alpha activation and restored insulin induced Protein Kinase C zeta activation, leading to amelioration of insulin-dependent glucose uptake. Interestingly, Ad-D4 administration improved insulin sensitivity also in high-fat diet treated obese C57Bl/6 mice. We conclude that PED/PEA-15-PLD1 interaction may represent a novel target for interventions aiming at improving glucose tolerance
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