599 research outputs found

    Neurocardiac risk stratification 6 hours after resuscitation from cardiac arrest

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    Introduction: • An increasing number of patients are resuscitated from out-ofhospital cardiac arrest. Triage to optimal treatment pathways could improve and increase the efficacy of post-resuscition care. • Despite great variability in etiology, duration, and patterns of injury from cardiac arrest, post-resuscitation treatment guidelines emphasize standard treatments. We hypothesize that by categorizing competing risks very early after resuscitation, it may be possible to improve the efficacy and efficiency of care. • When measured very early after resuscitation, suppression ratio (SR, the percentage of suppressed EEG), correlates with severity of brain injury and the likelihood of poor neurological outcome. • The CREST score2 is a validated model to predict circulatoryetiology death (CED) based on: Coronary artery disease, initial nonshockable Rhythm, Ejection fraction25 minutes

    T Cells Specific for a Mycobacterial Glycolipid Expand after Intravenous Bacillus Calmette-Guérin Vaccination

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    Intradermal vaccination with Mycobacterium bovis bacillus Calmette-Guérin (BCG) protects infants from disseminated tuberculosis, and i.v. BCG protects nonhuman primates (NHP) against pulmonary and extrapulmonary tuberculosis. In humans and NHP, protection is thought to be mediated by T cells, which typically recognize bacterial peptide Ags bound to MHC proteins. However, during vertebrate evolution, T cells acquired the capacity to recognize lipid Ags bound to CD1a, CD1b, and CD1c proteins expressed on APCs. It is unknown whether BCG induces T cell immunity to mycobacterial lipids and whether CD1-restricted T cells are resident in the lung. In this study, we developed and validated Macaca mulatta (Mamu) CD1b and CD1c tetramers to probe ex vivo phenotypes and functions of T cells specific for glucose monomycolate (GMM), an immunodominant mycobacterial lipid Ag. We discovered that CD1b and CD1c present GMM to T cells in both humans and NHP. We show that GMM-specific T cells are expanded in rhesus macaque blood 4 wk after i.v. BCG, which has been shown to protect NHP with near-sterilizing efficacy upon M. tuberculosis challenge. After vaccination, these T cells are detected at high frequency within bronchoalveolar fluid and express CD69 and CD103, markers associated with resident memory T cells. Thus, our data expand the repertoire of T cells known to be induced by whole cell mycobacterial vaccines, such as BCG, and show that lipid Ag-specific T cells are resident in the lungs, where they may contribute to protective immunity

    Comment on the narrow structure reported by Amaryan et al

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    The CLAS Collaboration provides a comment on the physics interpretation of the results presented in a paper published by M. Amaryan et al. regarding the possible observation of a narrow structure in the mass spectrum of a photoproduction experiment.Comment: to be published in Physical Review

    Absorption of the ω\omega and ϕ\phi Mesons in Nuclei

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    Due to their long lifetimes, the ω\omega and ϕ\phi mesons are the ideal candidates for the study of possible modifications of the in-medium meson-nucleon interaction through their absorption inside the nucleus. During the E01-112 experiment at the Thomas Jefferson National Accelerator Facility, the mesons were photoproduced from 2^{2}H, C, Ti, Fe, and Pb targets. This paper reports the first measurement of the ratio of nuclear transparencies for the e+ee^{+}e^{-} channel. The ratios indicate larger in-medium widths compared with what have been reported in other reaction channels.Comment: 6 pages, 4 figure

    Differential cross sections and recoil polarizations for the reaction gamma p -> K+ Sigma0

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    High-statistics measurements of differential cross sections and recoil polarizations for the reaction γpK+Σ0\gamma p \rightarrow K^+ \Sigma^0 have been obtained using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (s\sqrt{s}) from 1.69 to 2.84 GeV, with an extensive coverage in the K+K^+ production angle. Independent measurements were made using the K+pπK^{+}p\pi^{-}(γ\gamma) and K+pK^{+}p(π,γ\pi^-, \gamma) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR and LEPS results, while offering better statistical precision and a 300-MeV increase in s\sqrt{s} coverage. Above s2.5\sqrt{s} \approx 2.5 GeV, tt- and uu-channel Regge scaling behavior can be seen at forward- and backward-angles, respectively. Our recoil polarization (PΣP_\Sigma) measurements represent a substantial increase in kinematic coverage and enhanced precision over previous world data. At forward angles we find that PΣP_\Sigma is of the same magnitude but opposite sign as PΛP_\Lambda, in agreement with the static SU(6) quark model prediction of PΣPΛP_\Sigma \approx -P_\Lambda. This expectation is violated in some mid- and backward-angle kinematic regimes, where PΣP_\Sigma and PΛP_\Lambda are of similar magnitudes but also have the same signs. In conjunction with several other meson photoproduction results recently published by CLAS, the present data will help constrain the partial wave analyses being performed to search for missing baryon resonances.Comment: 23 pages, 17 figure

    Signaling via interleukin-4, receptor alpha chain is required for successful vaccination against schistosomiasis in BALB/c mice

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    Radiation-attenuated (RA) schistosome larvae are potent stimulators of innate immune responses at the skin site of exposure (pinna) that are likely to be important factors in the development of Th1-mediated protective immunity. In addition to causing an influx of neutrophils, macrophages, and dendritic cells (DCs) into the dermis, RA larvae induced a cascade of chemokine and cytokine secretion following in vitro culture of pinna biopsy samples. While macrophage inflammatory protein 1 and interleukin-1 (IL-1) were produced transiently within the first few days, the Th1-promoting cytokines IL-12 and IL-18 were secreted at high levels until at least day 14. Assay of C3H/HeJ mice confirmed that IL-12 secretion was not due to lipopolysaccharide contaminants binding Toll-like receptor 4. Significantly, IL-12 p40 secretion was sustained in pinnae from vaccinated mice but not in those from nonprotected infected mice. In contrast, IL-10 was produced from both vaccinated and infected mice. This cytokine regulates IL-12-associated dermal inflammation, since in vaccinated IL-10/ mice, pinna thickness was greatly increased concurrent with elevated levels of IL-12 p40. A significant number of IL-12 p40 cells were detected as emigrants from in vitro-cultured pinnae, and most were within a population of rare large granular cells that were Ia, consistent with their being antigen-presenting cells. Labeling of IL-12 cells for CD11c, CD205, CD8, CD11b, and F4/80 indicated that the majority were myeloid DCs, although a proportion were CD11c F4/80, suggesting that macrophages were an additional source of IL-12 in the skin

    Near-threshold Photoproduction of Phi Mesons from Deuterium

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    We report the first measurement of the differential cross section on ϕ\phi-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, K+K^+ and KK^- near the theoretical production threshold of 1.57 GeV. The extracted differential cross sections dσdt\frac{d\sigma}{dt} for the initial photon energy from 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. This experiment establishes a baseline for a future experimental search for an exotic ϕ\phi-N bound state from heavier nuclear targets utilizing subthreshold/near-threshold production of ϕ\phi mesons

    Transverse Polarization of Σ+(1189)\Sigma^{+}(1189) in Photoproduction on a Hydrogen Target in CLAS

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    Experimental results on the Σ+(1189)\Sigma^+(1189) hyperon transverse polarization in photoproduction on a hydrogen target using the CLAS detector at Jefferson laboratory are presented. The Σ+(1189)\Sigma^+(1189) was reconstructed in the exclusive reaction γ+pKS0+Σ+(1189)\gamma+p\rightarrow K^{0}_{S} + \Sigma^+(1189) via the Σ+pπ0\Sigma^{+} \to p \pi^{0} decay mode. The KS0K^{0}_S was reconstructed in the invariant mass of two oppositely charged pions with the π0\pi^0 identified in the missing mass of the detected pπ+πp\pi^+\pi^- final state. Experimental data were collected in the photon energy range EγE_{\gamma} = 1.0-3.5 GeV (s\sqrt{s} range 1.66-2.73 GeV). We observe a large negative polarization of up to 95%. As the mechanism of transverse polarization of hyperons produced in unpolarized photoproduction experiments is still not well understood, these results will help to distinguish between different theoretical models on hyperon production and provide valuable information for the searches of missing baryon resonances.Comment: pages 1

    Precision measurements of g1g_1 of the proton and the deuteron with 6 GeV electrons

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    The inclusive polarized structure functions of the proton and deuteron, g1p and g1d, were measured with high statistical precision using polarized 6 GeV electrons incident on a polarized ammonia target in Hall B at Jefferson Laboratory. Electrons scattered at lab angles between 18 and 45 degrees were detected using the CEBAF Large Acceptance Spectrometer (CLAS). For the usual DIS kinematics, Q^2>1 GeV^2 and the final-state invariant mass W>2 GeV, the ratio of polarized to unpolarized structure functions g1/F1 is found to be nearly independent of Q^2 at fixed x. Significant resonant structure is apparent at values of W up to 2.3 GeV. In the framework of perturbative QCD, the high-W results can be used to better constrain the polarization of quarks and gluons in the nucleon, as well as high-twist contributions
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