367 research outputs found

    False-negative Histoplasma antigen in acute pulmonary histoplasmosis: the value of urinary concentration by ultrafiltration and heat denaturation of serum proteins in detection of Histoplasma antigen

    Get PDF
    We report an infant with localized pulmonary histoplasmosis in whom Histoplasma antibody assays, quantitative Histoplasma urine and serum antigen concentrations, and histopathologic findings of a mediastinal mass were nondiagnostic. A provisional diagnosis of histoplasmosis was established by using laboratory methods that increase the sensitivity of the antigen assay using ultrafiltration of urine and ethylenediaminetetraacetic acid/heat denaturation of serum proteins

    Growth and survival of sockeye salmon (Oncorhynchus nerka) from Karluk Lake and River, Alaska, in relation to climatic and oceanic regimes and indices, 1922–2000

    Get PDF
    We examined whether the relationship between climate and salmon production was linked through the effect of climate on the growth of sockeye salmon (Oncorhynchus nerka) at sea. Smolt length and juvenile, immature, and maturing growth rates were estimated from increments on scales of adult sockeye salmon that returned to the Karluk River and Lake system on Kodiak Island, Alaska, over 77 years, 1924–2000. Survival was higher during the warm climate regimes and lower during the cool regime. Growth was not correlated with survival, as estimated from the residuals of the Ricker stock-recruitment model. Juvenile growth was correlated with an atmospheric forcing index and immature growth was correlated with the amount of coastal precipitation, but the magnitude of winter and spring coastal downwelling in the Gulf of Alaska and the Pacific Northwest atmospheric patterns that influence the directional bifurcation of the Pacific Current were not related to the growth of Karluk sockeye salmon. However, indices of sea surface temperature, coastal precipitation, and atmospheric circulation in the eastern North Pacific were correlated with the survival of Karluk sockeye salmon. Winter and spring precipitation and atmospheric circulation are possible processes linking survival to climate variation in Karluk sockeye salmon

    Phosphoinositide-3 kinase inhibition modulates responses to rhinovirus by mechanisms that are predominantly independent of autophagy

    Get PDF
    Human rhinoviruses (HRV) are a major cause of exacerbations of airways disease. Aspects of cell signalling responses to HRV infection remain unclear, particularly with regard to signalling via PI3K, and the PI3K-dependent pathway, autophagy. We investigated the roles of PI3K and autophagy in the responses of epithelial cells to major and minor group HRV infection. The PI3K inhibitor 3-MA, commonly used to inhibit autophagy, markedly reduced HRV-induced cytokine induction. Further investigation of potential targets of 3-MA and comparison of results using this inhibitor to a panel of general and class I-selective PI3K inhibitors showed that several PI3Ks cooperatively regulate responses to HRV. Targeting by siRNA of the autophagy proteins Beclin-1, Atg7, LC3, alone or in combination, or targeting of the autophagy-specific class III PI3K had at most only modest effects on HRV-induced cell signalling as judged by induction of proinflammatory cytokine production. Our data indicate that PI3K and mTOR are involved in induction of proinflammatory cytokines after HRV infection, and that autophagy has little role in the cytokine response to HRV or control of HRV replication

    Light Vector Mesons in the Nuclear Medium

    Full text link
    The light vector mesons (ρ\rho, ω\omega, and ϕ\phi) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the ρ\rho meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to e+e−e^{+}e^{-}. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The ρ\rho meson mass spectrum was extracted after the ω\omega and ϕ\phi signals were removed in a nearly model-independent way. Comparisons were made between the ρ\rho mass spectra from the heavy targets (A>2A > 2) with the mass spectrum extracted from the deuterium target. With respect to the ρ\rho-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body effects such as collisional broadening and Fermi motion.Comment: 15 pages, 18 figures, 3 table

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

    Full text link
    The polarized longitudinal-transverse structure function σLTâ€Č\sigma_{LT^\prime} has been measured using the p(e⃗,eâ€Čπ+)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 σLTâ€Č\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

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

    Get PDF
    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≀tâ€Č≀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 tâ€Čt' 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

    Measurement of the Deuteron Structure Function F2 in the Resonance Region and Evaluation of Its Moments

    Full text link
    Inclusive electron scattering off the deuteron has been measured to extract the deuteron structure function F2 with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. The measurement covers the entire resonance region from the quasi-elastic peak up to the invariant mass of the final-state hadronic system W~2.7 GeV with four-momentum transfers Q2 from 0.4 to 6 (GeV/c)^2. These data are complementary to previous measurements of the proton structure function F2 and cover a similar two-dimensional region of Q2 and Bjorken variable x. Determination of the deuteron F2 over a large x interval including the quasi-elastic peak as a function of Q2, together with the other world data, permit a direct evaluation of the structure function moments for the first time. By fitting the Q2 evolution of these moments with an OPE-based twist expansion we have obtained a separation of the leading twist and higher twist terms. The observed Q2 behaviour of the higher twist contribution suggests a partial cancellation of different higher twists entering into the expansion with opposite signs. This cancellation, found also in the proton moments, is a manifestation of the "duality" phenomenon in the F2 structure function

    Measurement of Deeply Virtual Compton Scattering with a Polarized Proton Target

    Get PDF
    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

    Survey of A_LT' asymmetries in semi-exclusive electron scattering on He4 and C12

    Full text link
    Single spin azimuthal asymmetries A_LT' were measured at Jefferson Lab using 2.2 and 4.4 GeV longitudinally polarized electrons incident on He4 and C12 targets in the CLAS detector. A_LT' is related to the imaginary part of the longitudinal-transverse interference and in quasifree nucleon knockout it provides an unambiguous signature for final state interactions (FSI). Experimental values of A_LT' were found to be below 5%, typically |A_LT'| < 3% for data with good statistical precision. Optical Model in Eikonal Approximation (OMEA) and Relativistic Multiple-Scattering Glauber Approximation (RMSGA) calculations are shown to be consistent with the measured asymmetries.Comment: 9 pages, 5 figure
    • 

    corecore