130 research outputs found

    NLO QCD corrections to off-shell top-antitop production with leptonic decays at hadron colliders

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    We present details of a calculation of the cross section for hadronic top-antitop production in next-to-leading order (NLO) QCD, including the decays of the top and antitop into bottom quarks and leptons. This calculation is based on matrix elements for \nu e e+ \mu- \bar{\nu}_{\mu}b\bar{b} production and includes all non-resonant diagrams, interferences, and off-shell effects of the top quarks. Such contributions are formally suppressed by the top-quark width and turn out to be small in the inclusive cross section. However, they can be strongly enhanced in exclusive observables that play an important role in Higgs and new-physics searches. Also non-resonant and off-shell effects due to the finite W-boson width are investigated in detail, but their impact is much smaller than naively expected. We also introduce a matching approach to improve NLO calculations involving intermediate unstable particles. Using a fixed QCD scale leads to perturbative instabilities in the high-energy tails of distributions, but an appropriate dynamical scale stabilises NLO predictions. Numerical results for the total cross section, several distributions, and asymmetries are presented for Tevatron and the LHC at 7 TeV, 8 TeV, and 14 TeV.Comment: 61 pp. Matches version published in JHEP; one more reference adde

    Adjuvant radiation therapy in metastatic lymph nodes from melanoma

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    <p>Abstract</p> <p>Purpose</p> <p>To analyze the outcome after adjuvant radiation therapy with standard fractionation regimen in metastatic lymph nodes (LN) from cutaneous melanoma.</p> <p>Patients and methods</p> <p>86 successive patients (57 men) were treated for locally advanced melanoma in our institution. 60 patients (69%) underwent LN dissection followed by radiation therapy (RT), while 26 patients (31%) had no radiotherapy.</p> <p>Results</p> <p>The median number of resected LN was 12 (1 to 36) with 2 metastases (1 to 28). Median survival after the first relapse was 31.8 months. Extracapsular extension was a significant prognostic factor for regional control (p = 0.019). Median total dose was 50 Gy (30 to 70 Gy). A standard fractionation regimen was used (2 Gy/fraction). Median number of fractions was 25 (10 to 44 fractions). Patients were treated with five fractions/week. Patients with extracapsular extension treated with surgery followed by RT (total dose ≥50 Gy) had a better regional control than patients treated by surgery followed by RT with a total dose <50 Gy (80% vs. 35% at 5-year follow-up; p = 0.004).</p> <p>Conclusion</p> <p>Adjuvant radiotherapy was able to increase regional control in targeted sub-population (LN with extracapsular extension).</p

    Regulation of Endothelial Cell Adhesion Molecule Expression by Mast Cells, Macrophages, and Neutrophils

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    Leukocyte adhesion to the vascular endothelium and subsequent transendothelial migration play essential roles in the pathogenesis of cardiovascular diseases such as atherosclerosis. The leukocyte adhesion is mediated by localized activation of the endothelium through the action of inflammatory cytokines. The exact proinflammatory factors, however, that activate the endothelium and their cellular sources remain incompletely defined.Using bone marrow-derived mast cells from wild-type, Tnf(-/-), Ifng(-/-), Il6(-/-) mice, we demonstrated that all three of these pro-inflammatory cytokines from mast cells induced the expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), P-selectin, and E-selectin in murine heart endothelial cells (MHEC) at both mRNA and protein levels. Compared with TNF-α and IL6, IFN-γ appeared weaker in the induction of the mRNA levels, but at protein levels, both IL6 and IFN-γ were weaker inducers than TNF-α. Under physiological shear flow conditions, mast cell-derived TNF-α and IL6 were more potent than IFN-γ in activating MHEC and in promoting neutrophil adhesion. Similar observations were made when neutrophils or macrophages were used. Neutrophils and macrophages produced the same sets of pro-inflammatory cytokines as did mast cells to induce MHEC adhesion molecule expression, with the exception that macrophage-derived IFN-γ showed negligible effect in inducing VCAM-1 expression in MHEC.Mast cells, neutrophils, and macrophages release pro-inflammatory cytokines such as TNF-α, IFN-γ, and IL6 that induce expression of adhesion molecules in endothelium and recruit of leukocytes, which is essential to the pathogenesis of vascular inflammatory diseases

    Computed tomography in staging of patients with melanoma metastatic to the regional nodes

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    Background: This study addresses the yield and clinical impact of computed tomography (CT) imaging in otherwise asymptomatic patients with stage III melanoma metastatic to the regional nodes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41414/1/10434_2006_Article_BF02305552.pd

    Is the inflammasome a potential therapeutic target in renal disease?

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    The inflammasome is a large, multiprotein complex that drives proinflammatory cytokine production in response to infection and tissue injury. Pattern recognition receptors that are either membrane bound or cytoplasmic trigger inflammasome assembly. These receptors sense danger signals including damage-associated molecular patterns and pathogen-associated molecular patterns (DAMPS and PAMPS respectively). The best-characterized inflammasome is the NLRP3 inflammasome. On assembly of the NLRP3 inflammasome, post-translational processing and secretion of pro-inflammatory cytokines IL-1β and IL-18 occurs; in addition, cell death may be mediated via caspase-1. Intrinsic renal cells express components of the inflammasome pathway. This is most prominent in tubular epithelial cells and, to a lesser degree, in glomeruli. Several primary renal diseases and systemic diseases affecting the kidney are associated with NLRP3 inflammasome/IL-1β/IL-18 axis activation. Most of the disorders studied have been acute inflammatory diseases. The disease spectrum includes ureteric obstruction, ischaemia reperfusion injury, glomerulonephritis, sepsis, hypoxia, glycerol-induced renal failure, and crystal nephropathy. In addition to mediating renal disease, the IL-1/ IL-18 axis may also be responsible for development of CKD itself and its related complications, including vascular calcification and sepsis. Experimental models using genetic deletions and/or receptor antagonists/antiserum against the NLRP3 inflammasome pathway have shown decreased severity of disease. As such, the inflammasome is an attractive potential therapeutic target in a variety of renal diseases

    QCD and strongly coupled gauge theories : challenges and perspectives

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    We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe

    Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

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    Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.
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