606 research outputs found

    Synthesis of a novel electrospun polycaprolactone scaffold functionalized with ibuprofen for periodontal regeneration: An in vitro and in vivo study

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    Ibuprofen (IBU) has been shown to improve periodontal treatment outcomes. The aimof this study was to develop a new anti-inflammatory scaffold by functionalizing an electrospun nanofibrous poly-e-caprolactone membrane with IBU (IBU-PCL) and to evaluate its impact on periodontal inflammation, wound healing and regeneration in vitro and in vivo. IBU-PCL was synthesized through electrospinning. The effects of IBU-PCL on the proliferation and migration of epithelial cells (EC) and fibroblasts (FB) exposed to Porphyromonas gingivlais lipopolysaccharide (Pg-LPS) were evaluated through the AlamarBlue test and scratch assay, respectively. Anti-inflammatory and remodeling properties were investigated through Real time qPCR. Finally, the in vivo efficacy of the IBU-PCL membrane was assessed in an experimental periodontitis mouse model through histomorphometric analysis. The results showed that the anti-inflammatory effects of IBU on gingival cells were effectively amplified using the functionalizedmembrane. IBU-PCL reduced the proliferation and migration of cells challenged by Pg-LPS, as well as the expression of fibronectin-1, collagen-IV, integrin a3ß1 and laminin-5. In vivo, the membranes significantly improved the clinical attachment and IBU-PCL also reduced inflammation-induced bone destruction. These data showed that the IBU-PCL membrane could efficiently and differentially control inflammatory and migratory gingival cell responses and potentially promote periodontal regeneration

    New Measurement of Parity Violation in Elastic Electron-Proton Scattering and Implications for Strange Form Factors

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    We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The result is A = -15.05 +- 0.98(stat) +- 0.56(syst) ppm at the kinematic point theta_lab = 12.3 degrees and Q^2 = 0.477 (GeV/c)^2. The measurement implies that the value for the strange form factor (G_E^s + 0.392 G_M^s) = 0.025 +- 0.020 +- 0.014, where the first error is experimental and the second arises from the uncertainties in electromagnetic form factors. This measurement is the first fixed-target parity violation experiment that used either a `strained' GaAs photocathode to produce highly polarized electrons or a Compton polarimeter to continuously monitor the electron beam polarization.Comment: 8 pages, 4 figures, Tex, elsart.cls; revised version as accepted for Phys. Lett.

    Search for Θ+(1540)\Theta^+(1540) pentaquark in high statistics measurement of γp→Kˉ0K+n\gamma p \to \bar K^0 K^+ n at CLAS

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    The exclusive reaction γp→Kˉ0K+n\gamma p \to \bar K^0 K^+ n was studied in the photon energy range between 1.6-3.8 GeV searching for evidence of the exotic baryon Θ+(1540)→nK+\Theta^+(1540)\to nK^+. The decay to nK+nK^+ requires the assignment of strangeness S=+1S=+1 to any observed resonance. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility corresponding to an integrated luminosity of 70 pb−1pb^{-1}. No evidence for the Θ+\Theta^+ pentaquark was found. Upper limits were set on the production cross section as function of center-of-mass angle and nK+nK^+ mass. The 95% CL upper limit on the total cross section for a narrow resonance at 1540 MeV was found to be 0.8 nb.Comment: Submitted to Physical Review Letter

    Measurement of the Polarized Structure Function σLT′\sigma_{LT^\prime} for p(e⃗,e′π+)np(\vec{e},e'\pi^+)n in the Δ(1232)\Delta(1232) Resonance Region

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    The polarized longitudinal-transverse structure function σLT′\sigma_{LT^\prime} has been measured using the p(e⃗,e′π+)np(\vec e,e'\pi^+)n reaction in the Δ(1232)\Delta(1232) resonance region at Q2=0.40Q^2=0.40 and 0.65 GeV2^2. No previous σLT′\sigma_{LT^\prime} data exist for this reaction channel. The kinematically complete experiment was performed at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS) using longitudinally polarized electrons at an energy of 1.515 GeV. A partial wave analysis of the data shows generally better agreement with recent phenomenological models of pion electroproduction compared to the previously measured π0p\pi^0 p channel. A fit to both π0p\pi^0 p and π+n\pi^+ n channels using a unitary isobar model suggests the unitarized Born terms provide a consistent description of the non-resonant background. The tt-channel pion pole term is important in the π0p\pi^0 p channel through a rescattering correction, which could be model-dependent.Comment: 6 pages, LaTex, 5 eps figures: Submitted to PRC/Brief Reports v2: Updated referenc

    Deeply virtual and exclusive electroproduction of omega mesons

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    The exclusive omega electroproduction off the proton was studied in a large kinematical domain above the nucleon resonance region and for the highest possible photon virtuality (Q2) with the 5.75 GeV beam at CEBAF and the CLAS spectrometer. Cross sections were measured up to large values of the four-momentum transfer (-t < 2.7 GeV2) to the proton. The contributions of the interference terms sigma_TT and sigma_TL to the cross sections, as well as an analysis of the omega spin density matrix, indicate that helicity is not conserved in this process. The t-channel pi0 exchange, or more generally the exchange of the associated Regge trajectory, seems to dominate the reaction gamma* p -> omega p, even for Q2 as large as 5 GeV2. Contributions of handbag diagrams, related to Generalized Parton Distributions in the nucleon, are therefore difficult to extract for this process. Remarkably, the high-t behaviour of the cross sections is nearly Q2-independent, which may be interpreted as a coupling of the photon to a point-like object in this kinematical limit.Comment: 15 pages,19 figure

    Morphological and Molecular Evolution Are Not Linked in Lamellodiscus (Plathyhelminthes, Monogenea)

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    Lamellodiscus Johnston & Tiegs 1922 (Monogenea, Diplectanidae) is a genus of common parasites on the gills of sparid fishes. Here we show that this genus is probably undergoing a fast molecular diversification, as reflected by the important genetic variability observed within three molecular markers (partial nuclear 18S rDNA, Internal Transcribed Spacer 1, and mitonchondrial Cytochrome Oxidase I). Using an updated phylogeny of this genus, we show that molecular and morphological evolution are weakly correlated, and that most of the morphologically defined taxonomical units are not consistent with the molecular data. We suggest that Lamellodiscus morphology is probably constrained by strong environmental (host-induced) pressure, and discuss why this result can apply to other taxa. Genetic variability within nuclear 18S and mitochondrial COI genes are compared for several monogenean genera, as this measure may reflect the level of diversification within a genus. Overall our results suggest that cryptic speciation events may occur within Lamellodiscus, and discuss the links between morphological and molecular evolution

    Measurement of Deeply Virtual Compton Scattering with a Polarized Proton Target

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    The longitudinal target-spin asymmetry A_UL for the exclusive electroproduction of high energy photons was measured for the first time in p(e,e'p\gamma). The data have been accumulated at Jefferson Lab with the CLAS spectrometer using 5.7 GeV electrons and a longitudinally polarized NH_3 target. A significant azimuthal angular dependence was observed, resulting from the interference of the Deeply Virtual Compton Scattering and Bethe-Heitler processes. The amplitude of the sin(phi) moment is 0.252 +/- 0.042(stat) +/- 0.020(sys). Theoretical calculations are in good agreement with the magnitude and the kinematic dependence of the target-spin asymmetry, which is sensitive to the generalized parton distributions H and H-tilde.Comment: Modified text slightly, added reference

    Electroproduction of ϕ(1020)\phi(1020) mesons at 1.4≤Q2≤1.4\leq Q^2\leq GeV2^2 measured with the CLAS spectrometer

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    Electroproduction of exclusive ϕ\phi vector mesons has been studied with the CLAS detector in the kinematical range 1.4≤Q2≤3.81.4\leq Q^2\leq 3.8 GeV2^{2}, 0.0≤t′≤3.60.0\leq t^{\prime}\leq 3.6 GeV2^{2}, and 2.0≤W≤3.02.0\leq W\leq 3.0 GeV. The scaling exponent for the total cross section as 1/(Q2+Mϕ2)n1/(Q^2+M_{\phi}^2)^n was determined to be n=2.49±0.33n=2.49\pm 0.33. The slope of the four-momentum transfer t′t' distribution is bϕ=0.98±0.17b_{\phi}=0.98 \pm 0.17 GeV−2^{-2}. Under the assumption of s-channel helicity conservation (SCHC), we determine the ratio of longitudinal to transverse cross sections to be R=0.86±0.24R=0.86 \pm 0.24. A 2-gluon exchange model is able to reproduce the main features of the data.Comment: Phys Rev C, 15 pages, 18 figure

    Observation of exclusive DVCS in polarized electron beam asymmetry measurements

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    We report the first results of the beam spin asymmetry measured in the reaction e + p -> e + p + gamma at a beam energy of 4.25 GeV. A large asymmetry with a sin(phi) modulation is observed, as predicted for the interference term of Deeply Virtual Compton Scattering and the Bethe-Heitler process. The amplitude of this modulation is alpha = 0.202 +/- 0.028. In leading-order and leading-twist pQCD, the alpha is directly proportional to the imaginary part of the DVCS amplitude.Comment: 6 pages, 5 figure

    Observation of an Exotic S=+1S=+1 Baryon in Exclusive Photoproduction from the Deuteron

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    In an exclusive measurement of the reaction γd→K+K−pn\gamma d \to K^+ K^- p n, a narrow peak that can be attributed to an exotic baryon with strangeness S=+1S=+1 is seen in the K+nK^+n invariant mass spectrum. The peak is at 1.542±0.0051.542\pm 0.005 GeV/c2^2 with a measured width of 0.021 GeV/c2^2 FWHM, which is largely determined by experimental mass resolution. The statistical significance of the peak is 5.2±0.6σ5.2 \pm 0.6 \sigma. The mass and width of the observed peak are consistent with recent reports of a narrow S=+1S=+1 baryon by other experimental groups.Comment: 5 pages, 5 figure
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