2,721 research outputs found

    finite element transient modelling for whole engine secondary air system thermomechanical analysis

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    Abstract This paper presents a new procedure developed in cooperation with Ansaldo Energia and aimed to predict metal temperatures in a gas turbine whole engine with an axisymmetric transient finite element approach. The 2D model includes a dedicated thermal fluid network where mass flow rates and pressure distributions are provided by external fluid network solvers in terms of time serie, while fluid-metal temperatures are computed through a customized version of CalculiX ® . This work represents a first insight about a fully integrated WEM ( Whole Engine Modelling ) procedure currently under development. The future implementation steps will be oriented to the usage of a customized version of the native CalculiX ® fluid network solver and the implementation of a system of monitoring and updating of the secondary air system (SAS) geometry. The aim is to progress from the current partly coupled approach with previously assessed mass flow and pressure distributions, to a fully integrated procedure able to take into account the interaction between the SAS fluid properties and the modifications in the geometry caused by mechanical and thermal loads. In this paper, the methodology will be presented introducing some details about the main modelling aspects and illustrating some preliminary results from the test of the procedure applied to a simplified model representative of a real engine geometry under transient conditions

    Indagine sismica a riflessione ad alta risoluzione con sorgente vibratoria Ivi-MiniVib svolta nel comune di Piedimonte Etneo (CT) in localitĂ  Presa.

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    Il presente lavoro ha avuto come obiettivo lo studio dettagliato della porzione superficiale (0-500 metri di profondità) della faglia Pernicana attraverso l’acquisizione e l’elaborazione di dati sismici a riflessione e rifrazione ad alta risoluzione. E’ stato acquisito un profilo sismico di 715 metri, in località Presa nel comune di Piedimonte Etneo (CT), mediante l’impiego di una sorgente sismica vibratoria ad alta risoluzione. Questo sito è stato scelto in quanto è attraversato dalla rottura superficiale indotta dalla faglia Pernicana

    Elongated styloid process evaluation on digital panoramic radiograph in a North Italian population

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    The aim of this study is to evaluate the prevalence of elongated styloid process in digital panoramic radiographs in a North Italian population in relation to age, gender and side. This study was performed as a retrospective analysis on digital panoramic radiographs of 600 (271 males and 329 females) Italian patients between 6 and 87 years old. The styloid process length were measured using the measuring tool of Sidexis Software. It was measured from the point where it left the temporal bone plate to its tip. Styloid processes measuring more than 30 mm were considered elongated. Chi-squared and Fisher tests were used and the test is considered significant if the p-value is lower or equal to 0.05. Thirty-three per cent of the patients showed an elongated styloid process. Seventeen per cent were elongated on both right and left side, fifteen point nine per cent were elongated only in one side. The prevalence of elongated styloid process was high and a progressive increase of the elongation prevalence was found in older groups

    Band 3 is an anchor protein and a target for SHP-2 tyrosine phosphatase in human erythrocytes

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    AbstractTyr phosphorylation of the multifunctional transmembrane protein band 3 has been implicated in several erythrocyte functions and disorders. We previously demonstrated that pervanadate treatment of human erythrocytes induces band-3 Tyr phosphorylation, which is catalyzed by the sequential action of tyrosine kinase Syk and tyrosine kinase(s) belonging to the Src family. In this study, we show that Tyr phosphorylation of band 3, elicited by pervanadate, N-ethylmaleimide, or diamide, greatly increases band-3 interaction with the tyrosine phosphatase SHP-2 in parallel with the translocation of SHP-2 to erythrocyte membranes. These events seem to be mediated by Src-like catalyzed phosphorylation of band 3 because both SHP-2 translocation to cellular membranes and its interaction with Tyr-phosphorylated protein are greatly counteracted by PP2, a specific inhibitor of Src kinases. Binding-competition experiments demonstrate that SHP-2 recruitment to band 3 occurs via its SH2 domain(s). In particular, our data support the view that SHP-2 docks specifically with P-Y359 of band 3. Experiments performed with intact erythrocytes in the presence of the SHP-2 inhibitor calpeptin suggest that, once recruited to Tyr-phosphorylated band 3, the tyrosine phosphatase dephosphorylates the protein. P-Y8, 21, and 904 are the residues affected by SHP-2, as judged by 32P-peptide mapping of band 3 digested with trypsin. These results indicate that in treated erythrocytes, recruitment of cytosolic SHP-2 to band 3 is a prerequisite for the subsequent dephosphorylation of the transmembrane protein

    Linear Accelerator Test Facility at LNF Conceptual Design Report

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    Test beam and irradiation facilities are the key enabling infrastructures for research in high energy physics (HEP) and astro-particles. In the last 11 years the Beam-Test Facility (BTF) of the DA{\Phi}NE accelerator complex in the Frascati laboratory has gained an important role in the European infrastructures devoted to the development and testing of particle detectors. At the same time the BTF operation has been largely shadowed, in terms of resources, by the running of the DA{\Phi}NE electron-positron collider. The present proposal is aimed at improving the present performance of the facility from two different points of view: extending the range of application for the LINAC beam extracted to the BTF lines, in particular in the (in some sense opposite) directions of hosting fundamental physics and providing electron irradiation also for industrial users; extending the life of the LINAC beyond or independently from its use as injector of the DA{\Phi}NE collider, as it is also a key element of the electron/positron beam facility. The main lines of these two developments can be identified as: consolidation of the LINAC infrastructure, in order to guarantee a stable operation in the longer term; upgrade of the LINAC energy, in order to increase the facility capability (especially for the almost unique extracted positron beam); doubling of the BTF beam-lines, in order to cope with the signicant increase of users due to the much wider range of applications.Comment: 71 page

    Prodromal angina and risk of 2-year cardiac mortality in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous intervention

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    We sought to investigate the prognostic significance of prodromal angina (PA) in unselected patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI) and its additive predictive value to the GRACE score.We prospectively enrolled 3015 consecutive STEMI patients undergoing PPCI. Patients were divided in 2 groups according to the presence or absence of PA. Multivariable Cox regression was used to establish the relation to 2-year cardiac mortality of PA.The mean age of the study population was 68 (±14) years; 2178 patients (72%) were male. During follow-up, 395 (13%) patients died with 278 of these (9.2%) suffering from cardiac mortality. Kaplan-Meier estimates showed a survival rate of 95% and 87% for patients with PA and no PA, respectively (log rank test < 0.001). After multivariable analysis, patients with PA had still a lower risk of 2 years' cardiac mortality compared with patients without PA (adjusted hazard ratio = 0.50; 95% confidence interval [CI] 1.06-1.81, P = .001). Evaluation of net reclassification improvement showed that reclassification improved by 0.16% in case patients, whereas classification worsened in control patients by 1.08% leading to a net reclassification improvement of -0.93% (95% CI: -0.98, -0.88).In patients with STEMI undergoing PPCI the presence of PA is independently associated with a lower risk of 2-year cardiac mortality. However, the incorporation of this variable to the GRACE score slightly worsened the classification of risk. Accordingly, it seems unlikely that the evaluation of PA may be useful in clinical practice

    Oscheius tipulae in Italy: Evidence of an Alien Isolate in the Integral Natural Reserve of Montecristo Island (Tuscany)

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    Montecristo Island is an integral natural reserve of the Tuscan Archipelago National Park (Central Italy), characterized by a peculiar assemblage of flora and fauna, with several endemic taxa, and also with a high number of alien species. During a soil survey, we found an alien Oscheius tipulae Lam &Webster, 1971 isolate, phylogenetically close to others from South America. In this article, we examined the possible pathways of introduction of this nematode. Because of the high number of alien plants in this protected area and the low desiccation survival ability of O. tipulae, we hypothesized that the presence of this alien nematode isolate may be related to the soil of introduced plants, although historical association with plant-associated invertebrates is also possible. Further studies with more populations and marker molecules are necessary to investigate the distribution of O. tipulae and the possible impact on this natural reserve

    Klebsiella pneumoniae Lipopolysaccharides Serotype O2afg Induce Poor Inflammatory Immune Responses Ex Vivo

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    Currently, Klebsiella pneumoniae is a pathogen of clinical relevance due to its plastic ability of acquiring resistance genes to multiple antibiotics. During K. pneumoniae infections, lipopolysaccharides (LPS) play an ambiguous role as they both activate immune responses but can also play a role in immune evasion. The LPS O2a and LPS O2afg serotypes are prevalent in most multidrug resistant K. pneumoniae strains. Thus, we sought to understand if those two particular LPS serotypes were involved in a mechanism of immune evasion. We have extracted LPS (serotypes O1, O2a and O2afg) from K. pneumoniae strains and, using human monocytes ex vivo, we assessed the ability of those LPS antigens to induce the production of pro-inflammatory cytokines and chemokines. We observed that, when human monocytes are incubated with LPS serotypes O1, O2a or O2afg strains, O2afg and, to a lesser extent, O2a but not O1 failed to elicit the production of pro-inflammatory cytokines and chemokines, which suggests a role in immune evasion. Our preliminary data also shows that nuclear translocation of NF-ÎşB, a process which regulates an immune response against infections, occurs in monocytes incubated with LPS O1 and, to a smaller extent, with LPS O2a, but not with the LPS serotype O2afg. Our results indicate that multidrug resistant K. pneumoniae expressing LPS O2afg serotypes avoid an initial inflammatory immune response and, consequently, are able to systematically spread inside the host unharmed, which results in the several pathologies associated with this bacterium

    Reduced Mortality With Antiplatelet Therapy Deescalation After Percutaneous Coronary Intervention in Acute Coronary Syndromes: A Meta-Analysis

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    Background:Antiplatelet therapy deescalation has been suggested as an alternative to standard treatment with potent dual antiplatelet therapy (DAPT) for 1 year in low bleeding risk patients with acute coronary syndromes undergoing percutaneous coronary intervention to mitigate the increased risk of bleeding. Whether this strategy preserves the ischemic and survival benefits of potent DAPT is uncertain. Methods:We performed a pairwise meta-analysis in patients with acute coronary syndrome undergoing percutaneous coronary intervention treated with either 1-year standard potent DAPT versus deescalation therapy (potent DAPT for 1-3 months followed by either reduced potency DAPT or ticagrelor monotherapy for up to 1 year). Randomized trials comparing standard DAPT versus deescalation therapy in patients with acute coronary syndrome undergoing percutaneous coronary intervention were searched through MEDLINE, EMBASE, Cochrane databases, and proceedings of international meetings. The primary end point was 1-year all-cause mortality. Results:The meta-analysis included 6 trials in which 20 837 patients were randomized to potent DAPT for 1 to 3 months followed by deescalation therapy for up to 1 year (n=10 392) or standard potent DAPT for 1 year (n=10 445). Deescalation therapy was associated with lower 1-year rates of all-cause mortality compared with standard therapy (odds ratio, 0.75 [95% CI, 0.59-0.95]; P=0.02). Deescalation therapy was also associated with lower rates of major bleeding (odds ratio, 0.59 [95% CI, 0.48-0.72]; P<0.0001), with no significant difference in major adverse cardiac events (major adverse cardiovascular events; odds ratio, 0.89 [95% CI, 0.77-1.04]; P=0.14). Conclusions:In low bleeding risk patients with acute coronary syndrome undergoing percutaneous coronary intervention, compared with 1-year of potent DAPT, antiplatelet therapy deescalation therapy after 1 to 3 months was associated with decreased mortality and major bleeding with similar rates of major adverse cardiovascular events
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