1,291 research outputs found

    Streptococcus suis in invasive human infections in Poland : clonality and determinants of virulence and antimicrobial resistance

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    The purpose of this study was to perform an analysis of Streptococcus suis human invasive isolates, collected in Poland by the National Reference Centre for Bacterial Meningitis. Isolates obtained from 21 patients during 2000–2013 were investigated by phenotypic tests, multilocus sequence typing (MLST), analysis of the TR9 locus from the multilocus variable number tandem repeat (VNTR) analysis (MLVA) scheme and pulsed-field gel electrophoresis (PFGE) of SmaI-digested DNA. Determinants of virulence and antimicrobial resistance were detected by polymerase chain reaction (PCR) and analysed by sequencing. All isolates represented sequence type 1 (ST1) and were suggested to be serotype 2. PFGE and analysis of the TR9 locus allowed the discrimination of four and 17 types, respectively. Most of the isolates were haemolysis- and DNase-positive, and around half of them formed biofilm. Genes encoding suilysin, extracellular protein factor, fibronectin-binding protein, muramidase-released protein, surface antigen one, enolase, serum opacity factor and pili were ubiquitous in the studied group, while none of the isolates carried sequences characteristic for the 89K pathogenicity island. All isolates were susceptible to penicillin, cefotaxime, imipenem, moxifloxacin, chloramphenicol, rifampicin, gentamicin, linezolid, vancomycin and daptomycin. Five isolates (24 %) were concomitantly non-susceptible to erythromycin, clindamycin and tetracycline, and harboured the tet(O) and erm(B) genes; for one isolate, lsa(E) and lnu(B) were additionally detected. Streptococcus suis isolated in Poland from human invasive infections belongs to a globally distributed clonal complex of this pathogen, enriched in virulence markers. This is the first report of the lsa(E) and lnu(B) resistance genes in S. suis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10096-016-2616-x) contains supplementary material, which is available to authorized users

    Comparative studies of optical absorption, photoluminescence and EPR spectra of PbMnI₂ bulk layers and nanocrystals

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    We report a study of the layered diluted magnetic semiconductor (DMS) Pb₁₋xMnxI₂ in 3D bulk layers and nanocrystal form by using optical absorption, photoluminescence and electron paramagnetic resonance (EPR). The samples of the bulk Pb₁₋xMnxI₂ crystals with x lying within the range 0 to 0.15 were grown using the Bridgman-Stockbarger technique. The composite nanostructures containing DMS nanocrystals of Pb₁₋xMnxI₂ were prepared by cooling the boiling saturated aqueous solution to room temperature. The exciton structure of the absorption spectra of nanoparticles exhibits blue shift due to the quantum confinement effect. In photoluminescence spectra of nanocrystals, two main peaks were revealed, which are attributed to the band-edge transitions and defect states. The EPR spectra for bulk layers and nanocrystals consist of an intense broad line and several weak narrow lines that correspond to hyperfine spectra of Mn²⁺ ions

    Combined QCD and electroweak analysis of HERA data

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    A simultaneous fit of parton distribution functions (PDFs) and electroweak parameters to HERA data on deep inelastic scattering is presented. The input data are the neutral current and charged current inclusive cross sections which were previously used in the QCD analysis leading to the HERAPDF2.0 PDFs. In addition, the polarisation of the electron beam was taken into account for the ZEUS data recorded between 2004 and 2007. Results on the vector and axial-vector couplings of the Z boson to u- and d-type quarks, on the value of the electroweak mixing angle and the mass of the W boson are presented. The values obtained for the electroweak parameters are in agreement with Standard Model predictions.Comment: 32 pages, 10 figures, accepted by Phys. Rev. D. Small corrections from proofing process and small change to Fig. 12 and Table

    Search for a narrow baryonic state decaying to pKS0{pK^0_S} and pˉKS0{\bar{p}K^0_S} in deep inelastic scattering at HERA

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    A search for a narrow baryonic state in the pKS0pK^0_S and pˉKS0\bar{p}K^0_S system has been performed in epep collisions at HERA with the ZEUS detector using an integrated luminosity of 358 pb1^{-1} taken in 2003-2007. The search was performed with deep inelastic scattering events at an epep centre-of-mass energy of 318 GeV for exchanged photon virtuality, Q2Q^2, between 20 and 100 GeV2\rm{} GeV^{2}. Contrary to evidence presented for such a state around 1.52 GeV in a previous ZEUS analysis using a sample of 121 pb1^{-1} taken in 1996-2000, no resonance peak was found in the p(pˉ)KS0p(\bar{p})K^0_S invariant-mass distribution in the range 1.45-1.7 GeV. Upper limits on the production cross section are set.Comment: 16 pages, 4 figures, accepted by Phys. Lett. B. Minor changes from journal reviewing process, including a small correction to figure

    Limits on the effective quark radius from inclusive epep scattering at HERA

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    The high-precision HERA data allows searches up to TeV scales for Beyond the Standard Model contributions to electron-quark scattering. Combined measurements of the inclusive deep inelastic cross sections in neutral and charged current epep scattering corresponding to a luminosity of around 1 fb1^{-1} have been used in this analysis. A new approach to the beyond the Standard Model analysis of the inclusive epep data is presented; simultaneous fits of parton distribution functions together with contributions of "new physics" processes were performed. Results are presented considering a finite radius of quarks within the quark form-factor model. The resulting 95% C.L. upper limit on the effective quark radius is 0.4310160.43\cdot 10^{-16} cm.Comment: 10 pages, 4 figures, accepted by Phys. Lett.

    Measurement of the cross-section ratio sigma_{psi(2S)}/sigma_{J/psi(1S)} in deep inelastic exclusive ep scattering at HERA

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    The exclusive deep inelastic electroproduction of ψ(2S)\psi(2S) and J/ψ(1S)J/\psi(1S) at an epep centre-of-mass energy of 317 GeV has been studied with the ZEUS detector at HERA in the kinematic range 2<Q2<802 < Q^2 < 80 GeV2^2, 30<W<21030 < W < 210 GeV and t<1|t| < 1 GeV2^2, where Q2Q^2 is the photon virtuality, WW is the photon-proton centre-of-mass energy and tt is the squared four-momentum transfer at the proton vertex. The data for 2<Q2<52 < Q^2 < 5 GeV2^2 were taken in the HERA I running period and correspond to an integrated luminosity of 114 pb1^{-1}. The data for 5<Q2<805 < Q^2 < 80 GeV2^2 are from both HERA I and HERA II periods and correspond to an integrated luminosity of 468 pb1^{-1}. The decay modes analysed were μ+μ\mu^+\mu^- and J/ψ(1S)π+πJ/\psi(1S) \,\pi^+\pi^- for the ψ(2S)\psi(2S) and μ+μ\mu^+\mu^- for the J/ψ(1S)J/\psi(1S). The cross-section ratio σψ(2S)/σJ/ψ(1S)\sigma_{\psi(2S)}/\sigma_{J/\psi(1S)} has been measured as a function of Q2,WQ^2, W and tt. The results are compared to predictions of QCD-inspired models of exclusive vector-meson production.Comment: 24 pages, 8 figure

    Measurement of neutral current e+/-p cross sections at high Bjorken x with the ZEUS detector

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    The neutral current e+/-p cross section has been measured up to values of Bjorken x of approximately 1 with the ZEUS detector at HERA using an integrated luminosity of 187 inv. pb of e-p and 142 inv. pb of e+p collisions at sqrt(s) = 318GeV. Differential cross sections in x and Q2, the exchanged boson virtuality, are presented for Q2 geq 725GeV2. An improved reconstruction method and greatly increased amount of data allows a finer binning in the high-x region of the neutral current cross section and leads to a measurement with much improved precision compared to a similar earlier analysis. The measurements are compared to Standard Model expectations based on a variety of recent parton distribution functions.Comment: 39 pages, 9 figure

    Building’ healt leakage investigation aimed at development of energy saving guidelines

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    This article is talking about developed technique of heat losses calculation for various purposes buildings. On the basis of performed calculations there were conducted detailed researches of the heat losses through buildingsfencing structures (wall, windows, floors, ceilings, etc.) for particular building, the installed capacity of its appliances was 208 kW. Executed researches enable ustomake a conclusion that the heat losses were 145,1 kW.Thus, 62,9 kW of capacity is excessive and therefore the equivalent number of heating units are to be excluded.Разработана методика расчёта потерь теплоты в зданиях различного назначения. На основе выполненных расчётов приведены детальные исследования потерь теплоты через ограждающие конструкции (стены, окна, полы, потолки, и проч.) конкретного здания, установленная мощность отопительных приборов которого 208 кВт. Выполненные исследования позволили заключить, что потери теплоты составляют 145,1 кВт. Таким образом, 62,9 кВт установленной мощности являются избыточными и, следовательно, эквивалентное число отопительных приборов необходимоисключить
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