76 research outputs found

    STRAIN DIFFERENCES IN THE EXPRESSION OF THE EPA-1-RESTRICTING ELEMENT

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    Epa-1-specific cytotoxic T lymphocytes (CTL) lyse epidermal cells (EC) of different Epa-1 + H-2 k strains, such as AKR, CBA, C58, and RF, at different levels. We used an H-2K k -specific monoclonal antibody (mAb) to test the hypothesis that this phenomenon is due to differences in the H-2-restricting element. Initially, we established the specificity of this mAb for the Epa-1-restricting element by demonstrating its capacity to inhibit the lysis of CBA EC by Epa-1-specific CTL. We then used it as the probe in a cellular radioimmunoassay to quantify the expression of the restricting element by EC of different H-2 k strains. We found that C58 and RF EC bound significantly less of the mAb than did CBA EC. Although AKR also bound less of the mAb than did CBA EC, the difference was not statistically significant. To examine the generality of this phenomenon, we quantified the expression of K k antigens on spleen cells (SC) of the same four strains. We found that RF SC, but not AKR or C58 SC, bound significantly less of the K k mAb than did CBA SC. Thus, the differential CTL lysis of Epa-1 + EC of different strains probably reflects differences in expression of the H-2-restricting element rather than of the nominal antigen.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75485/1/j.1744-313X.1987.tb00375.x.pd

    Far-infrared optical excitations in multiferroic TbMnO_3

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    We provide a detailed study of the reflectivity of multiferroic TbMnO_3 for wave numbers from 40 cm^{-1} to 1000 cm^{-1} and temperatures 5 K < T < 300 K. Excitations are studied for polarization directions E || a, the polarization where electromagnons are observed, and for E || c, the direction of the spontaneous polarization in this material. The temperature dependencies of eigenfrequencies, damping constants and polar strengths of all modes are studied and analyzed. For E || a and below the spiral ordering temperature of about 27 K we observe a transfer of optical weight from phonon excitations to electromagnons, which mainly involves low-frequency phonons. For E || c an unusual increase of the total polar strength and hence of the dielectric constant is observed indicating significant transfer of dynamic charge probably within manganese-oxygen bonds on decreasing temperatures.Comment: 8 pages, 7 figures, accepted for submission in European Physical Journal

    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 &#8722;1 and 19.7 fb &#8722;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 &#8594; hadrons, H &#8594; photons, and H &#8594; leptons. The results are characterized by an observed t t ¯ H tt¯H signal strength relative to the standard model cross section, &#956; = &#963;/&#963; SM ,under the assumption that the Higgs boson decays as expected in the standard model. The best fit value is &#956; = 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/ &#968; meson pairs in proton-proton collisions at s s&#8730; = 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 &#8722;1 . The two J/ &#968; mesons are fully reconstructed via their decays into &#956; + &#956; &#8722; pairs. This observation provides for the first time access to the high-transverse-momentum region of J/ &#968; 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/ &#968; transverse momentum ( p T J/ &#968; ) and rapidity (| y J/ &#968; |): | y J/ &#968; | 6.5 GeV/ c ; 1.2 4.5 GeV/ c . The total cross section, assuming unpolarized prompt J/ &#968; pair production is 1.49 ± 0.07 (stat) ±0.13 (syst) nb. Different assumptions about the J/ &#968; polarization imply modifications to the cross section ranging from &#8722;31% to +27%

    Measurements of the t(t)Overbar charge asymmetry using the dilepton decay channel in pp collisions at root s=7 TeV

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    The tt¯ charge asymmetry in proton-proton collisions at s&#8730; = 7 TeV is measured using the dilepton decay channel (ee, e &#956; , or &#956;&#956; ). The data correspond to a total integrated luminosity of 5.0 fb &#8722;1 , collected by the CMS experiment at the LHC. The tt and lepton charge asymmetries, defined as the differences in absolute values of the rapidities between the reconstructed top quarks and antiquarks and of the pseudorapidities between the positive and negative leptons, respectively, are measured to be A C = &#8722;0 . 010 ± 0 . 017 (stat . ) ± 0 . 008 (syst . ) and AlepC = 0 . 009 ± 0 . 010 (stat . ) ± 0 . 006 (syst . ). The lepton charge asymmetry is also measured as a function of the invariant mass, rapidity, and transverse momentum of the tt¯ system. All measurements are consistent with the expectations of the standard model

    Search for the Standard Model Higgs boson decaying into bb¯ produced in association with top quarks decaying hadronically in pp collisions at √s = 8 TeV with the ATLAS detector

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    A search for Higgs boson production in association with a pair of top quarks (tt¯ H) is performed, where the Higgs boson decays to bb¯, and both top quarks decay hadronically. The data used correspond to an integrated luminosity of 20.3 fb−1 of pp collisions at √s = 8 TeV collected with the ATLAS detector at the Large Hadron Collider. The search selects events with at least six energetic jets and uses a boosted decision tree algorithm to discriminate between signal and Standard Model background. The dominant multijet background is estimated using a dedicated data-driven technique. For a Higgs boson mass of 125 GeV, an upper limit of 6.4 (5.4) times the Standard Model cross section is observed (expected) at 95% confidence level. The best-fit value for the signal strength is μ = 1.6 ± 2.6 times the Standard Model expectation for mH = 125 GeV. Combining all tt¯ H searches carried out by ATLAS at √s = 8 and 7 TeV, an observed (expected) upper limit of 3.1 (1.4) times the Standard Model expectation is obtained at 95% confidence level, with a signal strength μ = 1.7 ± 0.8

    A global point prevalence survey of antimicrobial use in neonatal intensive care units: The no-more-antibiotics and resistance (NO-MAS-R) study

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    Background: Global assessment of antimicrobial agents prescribed to infants in the neonatal intensive care unit (NICU) may inform antimicrobial stewardship efforts. Methods: We conducted a one-day global point prevalence study of all antimicrobials provided to NICU infants. Demographic, clinical, and microbiologic data were obtained including NICU level, census, birth weight, gestational/chronologic age, diagnoses, antimicrobial therapy (reason for use; length of therapy), antimicrobial stewardship program (ASP), and 30-day in-hospital mortality. Findings: On July 1, 2019, 26 of infants (580/2,265; range, 0�100; median gestational age, 33 weeks; median birth weight, 1800 g) in 84 NICUs (51, high-income; 33, low-to-middle income) from 29 countries (14, high-income; 15, low-to-middle income) in five continents received �1 antimicrobial agent (92, antibacterial; 19, antifungal; 4, antiviral). The most common reasons for antibiotic therapy were �rule-out� sepsis (32) and �culture-negative� sepsis (16) with ampicillin (40), gentamicin (35), amikacin (19), vancomycin (15), and meropenem (9) used most frequently. For definitive treatment of presumed/confirmed infection, vancomycin (26), amikacin (20), and meropenem (16) were the most prescribed agents. Length of therapy for culture-positive and �culture-negative� infections was 12 days (median; IQR, 8�14) and 7 days (median; IQR, 5�10), respectively. Mortality was 6 (42, infection-related). An NICU ASP was associated with lower rate of antibiotic utilization (p = 0·02). Interpretation: Global NICU antibiotic use was frequent and prolonged regardless of culture results. NICU-specific ASPs were associated with lower antibiotic utilization rates, suggesting the need for their implementation worldwide. Funding: Merck & Co.; The Ohio State University College of Medicine Barnes Medical Student Research Scholarship © 2021 The Author

    The use of Brazilian vegetable oils in nanoemulsions: an update on preparation and biological applications

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    A century of trends in adult human height

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