274 research outputs found

    Molecular methods for the identification of Aspergillus species

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    Invasive aspergillosis (IA) is a leading cause of morbidity and mortality in immunocompromised hosts. In some institutions, species of Aspergillus less susceptible to amphotericin B than Aspergillus fumigatus are becoming more common, making an accurate identification of species important. However, species identification has traditionally relied on macroscopic colony characteristics and microscopic morphology, which may require several days of culture. Additional sub-culturing on specialized media may be required to induce conidia formation; in some cases conidia may never form, confounding identification. Therefore, rapid, nucleic acid-based methods that identify species of Aspergillus independent of morphology are now being developed to augment or replace phenotypic identification methods. The most successful methods to date have employed polymerase chain reaction (PCR) amplification of target sequences within the ribosomal RNA gene complex, including the 28S ribosomal subunit (D1-D2 region) and the internal transcribed spacers 1 and 2 (ITS1 and ITS2 regions). We therefore developed a PCR-based assay to differentiate medically important species of Aspergillus from one another, and from other opportunistic moulds and yeasts, by employing universal, pan-fungal primers directed to conserved ribosomal genes and species-specific DNA probes directed to the highly variable ITS2 region. Amplicons were then detected in a simple, colorimetric enzyme immunoassay format (PCR-EIA). DNA sequencing of the ITS1 and ITS2 regions and of the D1-D2 region was also conducted for the differentiation of species by comparative GenBank sequence analysis. The PCR-EIA method was found to be rapid, sensitive, and specific for the identification and differentiation of the most medically important species of Aspergillus. In addition, methods to identify species of Aspergillus by comparative GenBank sequence analysis were found to be more reliable using the ITS1 and ITS2 regions than the D1-D2 regio

    Correlation inequalities for classical and quantum XY models

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    We review correlation inequalities of truncated functions for the classical and quantum XY models. A consequence is that the critical temperature of the XY model is necessarily smaller than that of the Ising model, in both the classical and quantum cases. We also discuss an explicit lower bound on the critical temperature of the quantum XY model.Comment: 13 pages. Submitted to the volume "Advances in Quantum Mechanics: contemporary trends and open problems" of the INdAM-Springer series, proceedings of the INdAM meeting "Contemporary Trends in the Mathematics of Quantum Mechanics" (4-8 July 2016) organised by G. Dell'Antonio and A. Michelangel

    Rotational alignments in Np235 and the possible role of j15/2 neutrons

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    The role j15/2 neutron orbitals play in the transuranic region of actinides has been studied by exploring γ-ray transitions between yrast states in Np235, populated utilizing the nucleon-transfer reaction Np237(Sn116,Sn118). Two rotational sequences, presumably the two signatures of the ground-state band, have been delineated to high spin for the first time, with the α=+1/2 and α=-1/2 signature partners reaching 49/2 (tentatively 53/2+) and 47/2+ (tentatively 51/2+), respectively. Definite isotopic assignments for these in-band transitions were established through γ-ray cross correlations between Np235 and Sn118 and events where at least three γ rays corresponding to neptunium-like particles were detected. These transitions reveal clear upbends in the aligned angular momentum and kinematic moment of inertia plots; such a phenomenon could indicate a strong interaction between an aligned νj15/2 configuration crossing the ground-state band in Np235, which is based on a πi13/2 orbital. However, the lack of any signature splitting over the observed frequency range of the Np235 rotational sequences cannot remove the possibility of a πh9/2 assignment for the observed band. The role of the νj15/2 and πi13/2 alignment mechanisms in the deformed U-Pu region is discussed in light of the current spectroscopic data and in the context of the cranked-shell model

    Programmable antivirals targeting critical conserved viral RNA secondary structures from influenza A virus and SARS-CoV-2

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    Influenza A virus’s (IAV’s) frequent genetic changes challenge vaccine strategies and engender resistance to current drugs. We sought to identify conserved and essential RNA secondary structures within IAV’s genome that are predicted to have greater constraints on mutation in response to therapeutic targeting. We identified and genetically validated an RNA structure (packaging stem–loop 2 (PSL2)) that mediates in vitro packaging and in vivo disease and is conserved across all known IAV isolates. A PSL2-targeting locked nucleic acid (LNA), administered 3 d after, or 14 d before, a lethal IAV inoculum provided 100% survival in mice, led to the development of strong immunity to rechallenge with a tenfold lethal inoculum, evaded attempts to select for resistance and retained full potency against neuraminidase inhibitor-resistant virus. Use of an analogous approach to target SARS-CoV-2, prophylactic administration of LNAs specific for highly conserved RNA structures in the viral genome, protected hamsters from efficient transmission of the SARS-CoV-2 USA_WA1/2020 variant. These findings highlight the potential applicability of this approach to any virus of interest via a process we term ‘programmable antivirals’, with implications for antiviral prophylaxis and post-exposure therapy

    Multilaboratory evaluation of methods for detecting enteric viruses in soils.

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    Two candidate methods for the recovery and detection of viruses in soil were subjected to round robin comparative testing by members of the American Society for Testing and Materials D19:24:04:04 Subcommittee Task Group. Selection of the methods, designated "Berg" and "Goyal," was based on results of an initial screening which indicated that both met basic criteria considered essential by the task group. Both methods utilized beef extract solutions to achieve desorption and recovery of viruses from representative soils: a fine sand soil, an organic muck soil, a sandy loam soil, and a clay loam soil. One of the two methods, Goyal, also used a secondary concentration of resulting soil eluants via low-pH organic flocculation to achieve a smaller final assay volume. Evaluation of the two methods was simultaneously performed in replicate by nine different laboratories. Each of the produced samples was divided into portions, and these were respectively subjected to quantitative viral plaque assay by both the individual, termed independent, laboratory which had done the soil processing and a single common reference laboratory, using a single cell line and passage level. The Berg method seemed to produce slightly higher virus recovery values; however, the differences in virus assay titers for samples produced by the two methods were not statistically significant (P less than or equal to 0.05) for any one of the four soils. Despite this lack of a method effect, th

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

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    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

    Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data

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    A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<=|eta|<2.37 in the transverse energy range 45<=E_T<400GeV. The results are based on an integrated luminosity of 35 pb-1, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.Comment: 7 pages plus author list (18 pages total), 2 figures, 4 tables, final version published in Physics Letters
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