209 research outputs found

    The effect of soluble guanylate cyclase activators and a nitric oxide releasing PDE 5 inhibitor on cavernosal and anococcygeal smooth muscle function in conditions of nitric oxide deficiency

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    Introduction: PDE5 inhibitors improve erections by potentiating nitric oxide (NO)- cyclic guanosine monophosphate system. However, long-term diabetic patients have reduced efficacy secondary to dysfunction of NO system. The aim of this thesis was to investigate in-vitro effects of a PDE5 inhibitor (sildenafil), a soluble guanylate cyclase (sGC) activator (BAY41-2272) and an NO-releasing PDE5 inhibitor (NCX-911) on urogenital smooth muscle in conditions of NO deficiency. Method: The effect of these compounds was investigated on tone and electrical field stimulation-induced nitrergic relaxation of cavernosal (human and rabbit) and anococcygeal (rat) smooth muscle and compared to an NO donor (spermine-NONOate) and non-specific sGC activator (YC-1) in the absence/presence of inhibitor of NO synthesis (L-NAME) or inhibitor of sGC (ODQ). In a diabetic rat model, these compounds were assessed in untreated and L-NAME-treated tissues from non-diabetic and diabetic animals. Results: BAY41-2272 was more potent than YC-1 and spermine-NONOate at relaxing rabbit/human cavernosum. ODQ significantly decreased the potency of BAY41-2272 whereas L-NAME did not. BAY41-2272 potentiated nitrergic responses and partially reversed the inhibition of nitrergic responses by L-NAME. NCX-911 and sildenafil were equally potent at relaxing rabbit and human cavernosum. In presence of L-NAME the potency of sildenafil decreased significantly. Both compounds potentiated nitrergic relaxations equally but failed to induce relaxation in the presence of ODQ. Nitrergic relaxation was significantly decreased in the diabetic rats but still potentiated by BAY41-2272 but not by sildenafil or NCX-911. The potencies of NCX-911 and BAY41- 2272 were unaltered but that of sildenafil was significantly reduced in the diabetic animals. Conclusion: The rank of potency in control tissues was BAY41-2272 > NCX-11 = sildenafil; whereas in NO deficiency BAY 41-2272 > NCX-911 > sildenafil. Endogenous NO derived from nitrergic nerves is significantly decreased in diabetes. NO-releasing PDE5 inhibitors and sGC activators may be effective in management of diabetic erectile dysfunction

    Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

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    Search for the associated production of the Higgs boson with a top-quark pair

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    A search for the standard model Higgs boson produced in association with a top-quark pair t t ¯ H (tt¯H) is presented, using data samples corresponding to integrated luminosities of up to 5.1 fb −1 and 19.7 fb −1 collected in pp collisions at center-of-mass energies of 7 TeV and 8 TeV respectively. The search is based on the following signatures of the Higgs boson decay: H → hadrons, H → photons, and H → leptons. The results are characterized by an observed t t ¯ H tt¯H signal strength relative to the standard model cross section, μ = σ/σ SM ,under the assumption that the Higgs boson decays as expected in the standard model. The best fit value is μ = 2.8 ± 1.0 for a Higgs boson mass of 125.6 GeV

    Measurement of prompt Jψ\psi pair production in pp collisions at \sqrt s = 7 Tev

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    Production of prompt J/ ψ meson pairs in proton-proton collisions at s s√ = 7 TeV is measured with the CMS experiment at the LHC in a data sample corresponding to an integrated luminosity of about 4.7 fb −1 . The two J/ ψ mesons are fully reconstructed via their decays into μ + μ − pairs. This observation provides for the first time access to the high-transverse-momentum region of J/ ψ pair production where model predictions are not yet established. The total and differential cross sections are measured in a phase space defined by the individual J/ ψ transverse momentum ( p T J/ ψ ) and rapidity (| y J/ ψ |): | y J/ ψ | 6.5 GeV/ c ; 1.2 4.5 GeV/ c . The total cross section, assuming unpolarized prompt J/ ψ pair production is 1.49 ± 0.07 (stat) ±0.13 (syst) nb. Different assumptions about the J/ ψ polarization imply modifications to the cross section ranging from −31% to +27%

    Searches for supersymmetry using the M T2 variable in hadronic events produced in pp collisions at 8 TeV

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    Searches for supersymmetry (SUSY) are performed using a sample of hadronic events produced in 8 TeV pp collisions at the CERN LHC. The searches are based on the M T2 variable, which is a measure of the transverse momentum imbalance in an event. The data were collected with the CMS detector and correspond to an integrated luminosity of 19.5 fb-1. Two related searches are performed. The first is an inclusive search based on signal regions defined by the value of the M T2 variable, the hadronic energy in the event, the jet multiplicity, and the number of jets identified as originating from bottom quarks. The second is a search for a mass peak corresponding to a Higgs boson decaying to a bottom quark-antiquark pair, where the Higgs boson is produced as a decay product of a SUSY particle. For both searches, the principal backgrounds are evaluated with data control samples. No significant excess over the expected number of background events is observed, and exclusion limits on various SUSY models are derived

    Measurement of the Z boson differential cross section in transverse momentum and rapidity in proton-proton collisions at 8 TeV

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    We present a measurement of the Z boson differential cross section in rapidity and transverse momentum using a data sample of pp collision events at a centre-of-mass energy s=8 TeV, corresponding to an integrated luminosity of 19.7 fb-1. The Z boson is identified via its decay to a pair of muons. The measurement provides a precision test of quantum chromodynamics over a large region of phase space. In addition, due to the small experimental uncertainties in the measurement the data has the potential to constrain the gluon parton distribution function in the kinematic regime important for Higgs boson production via gluon fusion. The results agree with the next-to-next-to-leading-order predictions computed with the fewz program. The results are also compared to the commonly used leading-order MadGraph and next-to-leading-order powheg generators. © 2015 CERN for the benefit of the CMS Collaboration

    Identification techniques for highly boosted W bosons that decay into hadrons

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    Search for third-generation scalar leptoquarks in the tτ channel in proton-proton collisions at √s=8 TeV

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    A search for pair production of third-generation scalar leptoquarks decaying to top quark and τ lepton pairs is presented using proton-proton collision data at a center-of-mass energy of s = 8 s√=8 TeV collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 19.7 fb −1 . The search is performed using events that contain an electron or a muon, a hadronically decaying τ lepton, and two or more jets. The observations are found to be consistent with the standard model predictions. Assuming that all leptoquarks decay to a top quark and a τ lepton, the existence of pair produced, charge −1 / 3, third-generation leptoquarks up to a mass of 685 GeV is excluded at 95% confidence level. This result constitutes the first direct limit for leptoquarks decaying into a top quark and a τ lepton, and may also be applied directly to the pair production of bottom squarks decaying predominantly via the R-parity violating coupling λ 333 ′

    Forward-backward asymmetry of Drell-Yan lepton pairs in pp collisions at root s=8 TeV

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    Search for single production of scalar leptoquarks in proton-proton collisions at root s=8 TeV

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    Correction DOI:10.1103/PhysRevD.95.039906Peer reviewe
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