547 research outputs found

    Ionic gold demonstrates antimicrobial activity against Pseudomonas aeruginosa strains due to cellular ultrastructure damage

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    Due to the ever-increasing rise of antimicrobial resistant (AMR) bacteria, the development of alternative antimicrobial agents is a global priority. The antimicrobial activity of ionic gold was explored against four Pseudomonas aeruginosa strains with different AMR profiles in order to determine the antimicrobial activity of ionic gold and elucidate the mechanisms of action. Disc diffusion assays (zone of inhibition: ZoI) coupled with minimum inhibitory/bactericidal concentrations (MIC/MBC) were conducted to determine the antimicrobial efficacy of ionic gold. Scanning electron microscopy (SEM) was used to visualise morphological changes to the bacterial cell ultrastructure. Strains with increased AMR were slower to grow which is likely a fitness cost due to the enhanced AMR activity. Although greater concentrations of ionic gold were required to promote antimicrobial activity, ionic gold demonstrated similar antimicrobial values against all strains tested. Lowry assay results indicated that protein leakage was apparent following incubation with ionic gold, whilst SEM revealed cellular ultrastructure damage. This study suggests that the application of ionic gold as an alternative antimicrobial is promising, particularly against AMR P. aeruginosa. The antimicrobial activity of ionic gold against P. aeruginosa could potentially be utilised as an alternative therapeutic option in wound management, an approach that could benefit healthcare systems worldwide

    Anesthesia for intra-articular corticosteroid injections in juvenile idiopathic arthritis: A survey of pediatric rheumatologists

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    <p>Abstract</p> <p>Objective</p> <p>To determine the methods of anesthesia currently being used by pediatric rheumatologists when performing intra-articular corticosteroid injections (IACI).</p> <p>Study design</p> <p>A questionnaire was emailed to all members of the Childhood Arthritis & Rheumatology Research Alliance, a pediatric rheumatology research network in North America. The questionnaire consisted of 11 questions ranging from procedure technique, treatments prescribed for topical anesthesia and oral analgesia, and factors that might affect procedural pain.</p> <p>Results</p> <p>Seventy-four of 161 physicians (46%) responded to the questionnaire. On average, each physician injected 33 children (median 25, range 1-160) and 43 joints (median 30, range 1-150) yearly. Local anesthesia was used in children on average ≄ 8 years (range 2-16 years), with general anesthesia being more frequently used for younger children. All respondents used local anesthesia. The most commonly used methods of local anesthesia were EMLA<sup>Âź </sup>cream plus subcutaneous lidocaine (58.8%), ethyl chloride spray only (39.7%), EMLA<sup>Âź </sup>cream only (33.8%), subcutaneous lidocaine only (25%), and lidocaine iontophoresis only (11.8%). Buffering of the lidocaine was routinely done only 7.4% of the time.</p> <p>Conclusion</p> <p>Although pediatric rheumatologists in North America perform IACI on a large number of patients each year, a wide variety of methods are used to deliver local anesthesia with no accepted standard of care. More studies are needed to determine the optimal method of local anesthesia delivery to minimize pain associated with IACI.</p

    Modelling chemistry in the nocturnal boundary layer above tropical rainforest and a generalised effective nocturnal ozone deposition velocity for sub-ppbv NOx conditions

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    Measurements of atmospheric composition have been made over a remote rainforest landscape. A box model has previously been demonstrated to model the observed daytime chemistry well. However the box model is unable to explain the nocturnal measurements of relatively high [NO] and [O3], but relatively low observed [NO2]. It is shown that a one-dimensional (1-D) column model with simple O3 -NOx chemistry and a simple representation of vertical transport is able to explain the observed nocturnal concentrations and predict the likely vertical profiles of these species in the nocturnal boundary layer (NBL). Concentrations of tracers carried over from the end of the night can affect the atmospheric chemistry of the following day. To ascertain the anomaly introduced by using the box model to represent the NBL, vertically-averaged NBL concentrations at the end of the night are compared between the 1-D model and the box model. It is found that, under low to medium [NOx] conditions (NOx <1 ppbv), a simple parametrisation can be used to modify the box model deposition velocity of ozone, in order to achieve good agreement between the box and 1-D models for these end-of-night concentrations of NOx and O3. This parametrisation would could also be used in global climate-chemistry models with limited vertical resolution near the surface. Box-model results for the following day differ significantly if this effective nocturnal deposition velocity for ozone is implemented; for instance, there is a 9% increase in the following day’s peak ozone concentration. However under medium to high [NOx] conditions (NOx > 1 ppbv), the effect on the chemistry due to the vertical distribution of the species means no box model can adequately represent chemistry in the NBL without modifying reaction rate constants

    OPV strains circulation in HIV infected infants after National Immunisation Days in Bangui, Central African Republic

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    <p>Abstract</p> <p>Background</p> <p>Humans are the only host of polioviruses, thus the prospects of global polio eradication look reasonable. However, individuals with immunodeficiencies were shown to excrete vaccine derived poliovirus for long periods of time which led to reluctance to prolong the vaccination campaign for fear of this end result. Therefore, we aimed to assess the duration of excretion of poliovirus after the 2001 National Immunization Days according to Human immunodeficiency virus status.</p> <p>Findings</p> <p>Fifty three children were enrolled. Sequential stool samples were collected in between National Immunisation Days rounds and then every month during one year. Children were classified into 2 groups: no immunodepression (n = 38), immunodepression (n = 15) according to CD4+ lymphocytes cells count. Thirteen poliovirus strains were isolated from 11 children: 5 Human immunodeficiency virus positive and 6 Human immunodeficiency virus negative. None of the children excreted poliovirus for more than 4 weeks. The restriction fragment length polymorphism analysis showed that all strains were of Sabin origin including a unique Polio Sabine Vaccine types 2 and 3 (S2/S3) recombinant.</p> <p>Conclusions</p> <p>From these findings we assume that Human immunodeficiency virus positive children are not a high risk population for long term poliovirus excretion. More powerful studies are needed to confirm our findings.</p

    Predicting the Presence of Companions for Stripped-envelope Supernovae: The Case of the Broad-lined Type Ic SN 2002ap

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    Many young, massive stars are found in close binaries. Using population synthesis simulations we predict the likelihood of a companion star being present when these massive stars end their lives as core-collapse supernovae (SNe). We focus on stripped-envelope SNe, whose progenitors have lost their outer hydrogen and possibly helium layers before explosion. We use these results to interpret new Hubble Space Telescope observations of the site of the broad-lined Type Ic SN 2002ap, 14 years post-explosion. For a subsolar metallicity consistent with SN 2002ap, we expect a main-sequence (MS) companion present in about two thirds of all stripped-envelope SNe and a compact companion (likely a stripped helium star or a white dwarf/neutron star/black hole) in about 5% of cases. About a quarter of progenitors are single at explosion (originating from initially single stars, mergers, or disrupted systems). All of the latter scenarios require a massive progenitor, inconsistent with earlier studies of SN 2002ap. Our new, deeper upper limits exclude the presence of an MS companion star >8–10  M⊙\,{M}_{\odot }, ruling out about 40% of all stripped-envelope SN channels. The most likely scenario for SN 2002ap includes nonconservative binary interaction of a primary star initially â‰Č23 M⊙\lesssim 23\,{M}_{\odot }. Although unlikely (<1% of the scenarios), we also discuss the possibility of an exotic reverse merger channel for broad-lined Type Ic events. Finally, we explore how our results depend on the metallicity and the model assumptions and discuss how additional searches for companions can constrain the physics that govern the evolution of SN progenitors.This work is based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. It is also based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology, under a contract with NASA. Support was provided by NASA through grants GO-14075 and AR-14295 from STScI. We thank Andrew Dolphin for his patient advice on how best to implement artificial star tests in Dolphot. E.Z. is supported by a grant of the Netherlands Research School for Astronomy (NOVA). S.d.M. acknowledges support by a Marie Sklodowska-Curie Action (H2020 MSCA-IF-2014, project BinCosmos, ID 661502). A.V.F.'s group is also grateful for generous financial assistance from the Christopher R. Redlich Fund, the TABASGO Foundation, and NSF grant AST-1211916. N.S. is grateful for support from NSF grants AST-1312221 and AST-1515559. R.G.I. thanks the STFC for funding his Rutherford Fellowship under grant ST/L003910/1 and Churchill College, Cambridge, for his fellowship and access to their library

    MYO9B polymorphisms in multiple sclerosis

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    "Single-nucleotide polymorphisms (SNPs) in the 30 region of myosin IXB (MYO9B) gene have recently been reported to associate with different inflammatory or autoimmune diseases. We monitored for the association of MYO9B variants to multiple sclerosis (MS) in four Northern European populations. First, 18 SNPs including 6 SNPs with previous evidence for association to immune disorders, were tested in 730 Finnish MS families, but no linkage or family-based association was observed. To ensure the power to detect variants with a modest effect size, we further analyzed 10 variants in 899 Finnish cases and 1325 controls, and in a total of 1521 cases and 1476 controls from Denmark, Norway and Sweden, but found no association. Our results thereby do not support a major function of the tested MYO9B variants in MS. European Journal of Human Genetics (2009) 17, 840-843; doi: 10.1038/ejhg.2008.251; published online 14 January 2009""Single-nucleotide polymorphisms (SNPs) in the 30 region of myosin IXB (MYO9B) gene have recently been reported to associate with different inflammatory or autoimmune diseases. We monitored for the association of MYO9B variants to multiple sclerosis (MS) in four Northern European populations. First, 18 SNPs including 6 SNPs with previous evidence for association to immune disorders, were tested in 730 Finnish MS families, but no linkage or family-based association was observed. To ensure the power to detect variants with a modest effect size, we further analyzed 10 variants in 899 Finnish cases and 1325 controls, and in a total of 1521 cases and 1476 controls from Denmark, Norway and Sweden, but found no association. Our results thereby do not support a major function of the tested MYO9B variants in MS. European Journal of Human Genetics (2009) 17, 840-843; doi: 10.1038/ejhg.2008.251; published online 14 January 2009""Single-nucleotide polymorphisms (SNPs) in the 30 region of myosin IXB (MYO9B) gene have recently been reported to associate with different inflammatory or autoimmune diseases. We monitored for the association of MYO9B variants to multiple sclerosis (MS) in four Northern European populations. First, 18 SNPs including 6 SNPs with previous evidence for association to immune disorders, were tested in 730 Finnish MS families, but no linkage or family-based association was observed. To ensure the power to detect variants with a modest effect size, we further analyzed 10 variants in 899 Finnish cases and 1325 controls, and in a total of 1521 cases and 1476 controls from Denmark, Norway and Sweden, but found no association. Our results thereby do not support a major function of the tested MYO9B variants in MS. European Journal of Human Genetics (2009) 17, 840-843; doi: 10.1038/ejhg.2008.251; published online 14 January 2009"Peer reviewe

    Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

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    The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≄20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≀pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≀{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

    Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

    Observation of associated near-side and away-side long-range correlations in √sNN=5.02  TeV proton-lead collisions with the ATLAS detector

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    Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  Όb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∌0) correlation that grows rapidly with increasing ÎŁETPb. A long-range “away-side” (Δϕ∌π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ÎŁETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁥2Δϕ modulation for all ÎŁETPb ranges and particle pT
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