2,761 research outputs found

    Search for New Physics at the Fermilab Tevatron p¯p collider

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    We report on selected recent results from the CDF and D0 experiments on searches for physics beyond the Standard Model using data from the Tevatron collider running p¯p collisions at √s = 1960GeV

    QCD results from the Fermilab Tevatron p¯p Collider

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    Several selected quantum chromodynamics (QCD) measurements performed at the Fermilab Tevatron by the CDF and D0 Collaborations, using proton-antiproton collisions at a centre-of-mass energy of √s = 1.96TeV are reviewed. We will summarize the status of inclusive jet and dijet production crosssection measurements, which can be used to extract a precise value of the strong coupling constant and to search for physics beyond the Standard Model. We will then review results from the inclusive photon production cross-section measurement, as well as the associated production of photon with a light or heavy flavors jet. Finally we will describe various measurements concerning the production of vector bosons and jets

    Top Physics at the LHC

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    Top Physics at the LHC is reviewed with special emphasis on cross section measurements, top properties studies and production mechanisms (single top production

    Next to leading order eta production at hadron colliders

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    Inclusive eta production at hadron colliders is considered,based on evaluation of eta fragmentation functions at next to leading order. Absolute predictions at LHC and SSC are presented, including the ratio η/π0\eta/\pi^0, together with the estimate of the theoretical uncertainty, as a possible neutral background to the HγγH\to \gamma\gamma detection.Comment: 8 pages, latex, FNT/T-93/13,14 figures avilable upon reques

    Homocysteine induces cell death in H9C2 cardiomyocytes through the generation of peroxynitrite

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    Homocysteine (HCY) is toxic on blood vessels, but a potential direct toxicity of HCY on the heart is unknown. We addressed this issue by exposing H9C2 cardiomyocytes to HCY (0.1-5 mM) for up to 6h. At these concentrations, HCY reduced cell viability, induced necrosis and apoptosis and triggered the cleavage of caspase-3 and poly(ADP-ribose) polymerase (PARP). This was associated with the intracellular generation of the potent oxidant peroxynitrite. Removing peroxynitrite by the decomposition catalyst FeTPPS considerably reduced LDH release, DNA fragmentation, cleavage of caspase-3 and PARP, and restored normal cell morphology. In additional experiments performed in primary rat ventricular cardiomyocytes, HCY (1 mM, 6h) activated the phosphorylation of the MAP kinases ERK and JNK, two essential stress signaling kinases regulating myocardial apoptosis, hypertrophy and remodeling. These results provide the first demonstration that HCY kills cardiomyocytes through the generation of peroxynitrite and can activate key signaling cascades in the myocardium

    Peroxynitrite is a potent inhibitor of NF-{kappa}B activation triggered by inflammatory stimuli in cardiac and endothelial cell lines.

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    Peroxynitrite is a potent oxidant and nitrating species proposed as a direct effector of myocardial damage in numerous cardiac pathologies. Whether peroxynitrite also acts indirectly, by modulating cell signal transduction in the myocardium, has not been investigated. Therefore, we examined a possible role for peroxynitrite on the activation of NF-kappaB, a crucial pro-inflammatory transcription factor, in cultured H9C2 cardiomyocytes. H9C2 cells were stimulated with tumor necrosis factor-alpha or lipopolysaccharide following a brief (20-min) exposure to peroxynitrite. NF-kappaB activation (phosphorylation and degradation of its inhibitor IkappaBalpha, nuclear translocation of NF-kappaB p65, and NF-kappaB DNA binding) triggered by lipopolysaccharide or tumor necrosis factor-alpha was abrogated by peroxynitrite. Peroxynitrite also inhibited NF-kappaB in two human endothelial cell lines activated with tumor necrosis factor-alpha or interleukin-1beta. These effects were related to oxidative but not nitrative chemistry and were still being observed while nitration was suppressed by epicatechin. The mechanism of NF-kappaB inhibition by peroxynitrite was a complete blockade of phosphorylation and activation of the upstream kinase IkappaB kinase (IKK) beta, required for canonical, pro-inflammatory NF-kappaB activation. At the same time, peroxynitrite activated phosphorylation of NF-kappaB-inducing kinase and IKKalpha, considered as part of an alternative, noncanonical NF-kappaB activation pathway. Suppression of IKKbeta-dependent NF-kappaB activation translated into a marked inhibition of the transcription of NF-kappaB-dependent genes by peroxynitrite. Thus, peroxynitrite has a dual effect on NF-kappaB, inhibiting canonical IKKbeta-dependent NF-kappaB activation while activating NF-kappaB-inducing kinase and IKKalpha phosphorylation, which suggests its involvement in an alternative pathway of NF-kappaB activation. These findings offer new perspectives for the understanding of the relationships between redox stress and inflammation

    Waveguiding and photoluminescence in Er<sup>3+</sup>-doped Ta<sub>2</sub>O<sub>5</sub> planar waveguides

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    The optimization of erbium-doped Ta2O5 thin film waveguides deposited by magnetron sputtering onto thermally oxidized silicon wafer is described. Optical constants of the film were determined by ellipsometry. For the slab waveguides, background losses below 0.4dB/cm at 633nm have been obtained before post-annealing. The samples, when pumped at 980nm yielded abroad photoluminescence spectrum (FWHM ~50 nm) centred at 1534nm, corresponding to 4 I 13/2 to the 4 I 15/2 transition of Er3+ ion. The samples were annealed up to 600 °C and both photoluminescence power and fluorescence lifetime increase with post-annealing temperature and a fluorescence lifetime of 2.4ms was achieved, yielding promising results for compact waveguide amplifier

    Patient-reported outcome measures (PROMs) after elective hip, knee and shoulder arthroplasty: Protocol for a prospective cohort study

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    Background The number of hip, knee and shoulder arthroplasties continues to rise worldwide. The Organization for Economic Cooperation and Development has launched an initiative (called PaRIS Initiative) for the systematic collection of Patient Reported Outcome Measures (PROMs) in patients undergoing elective hip and knee arthroplasty. The Rizzoli Orthopedic Institute (IOR) was selected as a pilot center for the launch of the Initiative in Italy given that IOR hosts the Registry of Orthopedic Prosthetic Implants (RIPO), a region-wide registry which collects joint implant data from all the hospitals in the Emilia-Romagna Region. In this specific geographic area information related to PROMs after joint replacement is unknown. This paper describes the protocol of a study (PaRIS-IOR) that aims to implement the collection of a set of PROMs within an existing implant registry in Italy. The study will also investigate the temporal trend of PROMs in relation to the type of prosthesis and the type of surgical intervention. Methods The PaRIS-IOR study is a prospective, single site, cohort study that consists of the administration of PROMs questionnaires to patients on the list for elective arthroplasty. The questionnaires will be administered to the study population within 30 days before surgery, and then at 6 and 12 months following surgery. The study population will consist of consecutive adult patients undergoing either hip, knee or shoulder arthroplasty. The collected data will be linked with those routinely collected by the RIPO in order to assess the temporal trend of PROMs in relation to the type of prosthesis and the type of surgical intervention. Discussion The PaRIS-IOR study could have important implications in targeting the factors influencing functional outcomes and quality of life reported by patients after hip, knee and shoulder arthroplasty, and will also represent the first systematic collection of PROMs related to arthroplasty in Italy