1,171 research outputs found

    Inflammation and changes in cytokine levels in neurological feline infectious peritonitis.

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    Feline infectious peritonitis (FIP) is a progressive, fatal, predominantly Arthus-type immune-mediated disease that is triggered when cats are infected with a mutant enteric coronavirus. The disease presents variably with multiple organ failure, seizures, generalized effusion, or shock. Neurological FIP is clinically and pathologically more homogeneous than systemic 'wet' or 'dry' FIP; thus, comparison of cytokine profiles from cats with neurological FIP, wet FIP, and non-FIP neurological disease may provide insight into some baseline characteristics relating to the immunopathogenesis of neurological FIP. This study characterizes inflammation and changes in cytokines in the brain tissue of FIP-affected cats. Cellular infiltrates in cats with FIP included lymphocytes, plasma cells, neutrophils, macrophages, and eosinophils. IL-1 beta, IL-6, IL-12, IL-18, TNF-alpha, macrophage inhibitory protein (MIP)-1 alpha, and RANTES showed no upregulation in the brains of control cats, moderate upregulation in neurological FIP cats, and very high upregulation in generalized FIP cats. Transcription of IFN-gamma appeared upregulated in cats with systemic FIP and slightly downregulated in neurological FIP. In most cytokines tested, variance was extremely high in generalized FIP and much less in neurological FIP. Principal components analysis was performed in order to find the least number of 'components' that would summarize the cytokine profiles in cats with neurological FIP. A large component of the variance (91.7%) was accounted for by levels of IL-6, MIP-1 alpha, and RANTES. These findings provide new insight into the immunopathogenesis of FIP and suggest targets for immune therapy of this disease

    Measurement of the Far Infrared Magneto-Conductivity Tensor of Superconducting YBa2_2Cu3_3O7δ_{7-\delta } Thin Films

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    We report measurements of the far infrared transmission of superconducting YBa2_2Cu3_3O7δ_{7-\delta } thin films from 5 cm1^{-1} to 200 cm1^{-1} in fields up to 14TT. A Kramers-Kronig analysis of the magneto-transmission spectrum yields the magneto-conductivity tensor. The result shows that the magneto-conductivity of YBa2_2Cu3_3O7δ_{7-\delta } is dominated by three terms: a London term, a low frequency Lorentzian (ω1\omega _1\approx 3 cm1% ^{-1}) of width Γ1=\Gamma _1= 10 cm1^{-1} and a finite frequency Lorentzian of width Γ2=\Gamma _2= 17 cm1^{-1} at ω2=\omega _2= 24 cm1^{-1} in the hole cyclotron resonance active mode of circular polarization.\\Comment: Revised LaTex file (12 pages) + 4 Postscript figures, uuencoded. In response to referees' comments, we refined the paper a lot; we encourage you to download this revised versio

    Craters on silicon surfaces created by gas cluster ion impacts

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    Atomic force microscopy ~AFM! and high-resolution transmission electron microscope ~HRTEM! cross section imaging of individual gas cluster ion impact craters on Si~100! and Si~111! substrate surfaces is examined. The comparison between 3 and 24 kV cluster impacts from Ar and O2 gas sources is shown. Results for low fluence (1010 ions/cm2) 24 kV Ar individual cluster impacts onto a Si~100! and Si~111! substrate surfaces are compared with hybrid molecular dynamics ~HMD! simulations. A HMD method is used for modeling impacts of Arn (n5135, 225! clusters, with energies of 24–50 eV/atom, on Si~100! and Si~111! surfaces. On a Si~100!, craters are nearly triangular in cross section, with the facets directed along the close-packed ~111! planes. The Si~100! craters exhibit four-fold symmetry as imaged by cross-sectional HRTEM, and AFM top view, in agreement with modeling. In contrast, the shape of craters on a Si~111! shows a complicated six-pointed shape in the modeling, while AFM indicates three-fold symmetry of the impact. The lower energy 3 kV individual cluster impacts reveal the same crater shape in HRTEM cross section for both Ar and O2 gas clusters, but with shallower crater depth than for the higher-energy impacts. The kinetics of the Ar and O2 crater impacts may explain the successful use of higher-energy cluster impacts for etching material of higher initial surface roughness followed by the lower energy impacts as an effective finishing step to achieve smoother surfaces

    Inclusive One Jet Production With Multiple Interactions in the Regge Limit of pQCD

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    DIS on a two nucleon system in the regge limit is considered. In this framework a review is given of a pQCD approach for the computation of the corrections to the inclusive one jet production cross section at finite number of colors and discuss the general results.Comment: 4 pages, latex, aicproc format, Contribution to the proceedings of "Diffraction 2008", 9-14 Sep. 2008, La Londe-les-Maures, Franc

    Grain Boundary Induced Magneto-Far Infrared Resonances in Superconducting YBa2_2Cu3_3O7δ_{7-\delta } Thin Films

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    Spectral features induced by 45^{\circ } in-plane misoriented grains have been observed in the far infrared magneto-transmission of YBa2_2Cu3_3O7δ% _{7-\delta } thin films. Two strong dispersive features are found at 80 and 160 cm1cm^{-1} and a weaker one at 116 cm1cm^{-1}. The data can be well represented by Lorentzian oscillator contributions to the conductivity. Several possible interpretations are discussed. We conclude that the resonances are due to vortex core excitations.Comment: Latex file (14 pages) + 4 Postscript figures, uuencode

    Multifaceted contributions : health workers and smallpox eradication in India

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    Smallpox eradication in South Asia was a result of the efforts of many grades of health-workers. Working from within the confines of international organisations and government structures, the role of the field officials, who were of various nationalities and also drawn from the cities and rural enclaves of the countries in these regions, was crucial to the development and deployment of policies. However, the role of these personnel is often downplayed in official histories and academic histories, which highlight instead the roles played by a handful of senior officials within the World Health Organization and the federal governments in the sub-continent. This article attempts to provide a more rounded assessment of the complex situation in the field. In this regard, an effort is made to underline the great usefulness of the operational flexibility displayed by field officers, wherein lessons learnt in the field were made an integral part of deploying local campaigns; careful engagement with the communities being targeted, as well as the employment of short term workers from amongst them, was an important feature of this work

    The Chemical Evolution of Magnesium Isotopic Abundances in the Solar Neighbourhood

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    The abundance of the neutron-rich magnesium isotopes observed in metal-poor stars is explained quantitatively with a chemical evolution model of the local Galaxy that considers - for the first time - the metallicity-dependent contribution from intermediate mass stars. Previous models that simulate the variation of Mg isotopic ratios with metallicity in the solar neighbourhood have attributed the production of Mg25 and Mg26 exclusively to hydrostatic burning in massive stars. These models match the data well for [Fe/H]>-1.0 but severely underestimate Mg25/Mg24 and Mg26/Mg24 at lower metallicities. Earlier studies have noted that this discrepancy may indicate a significant role played by intermediate-mass stars. Only recently have detailed calculations of intermediate-mass stellar yields of Mg25 and Mg26 become available with which to test this hypothesis. In an extension of previous work, we present a model that successfully matches the Mg isotopic abundances in nearby Galactic disk stars through the incorporation of nucleosynthesis predictions of Mg isotopic production in asymptotic giant branch stars.Comment: 9 pages, 6 figures, to appear in Publications of the Astronomical Society of Australia (PASA) in 2003, vol. 20, No.

    Minor differences in body condition and immune status between avian influenza virus-infected and noninfected mallards: a sign of coevolution?

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    Wildlife pathogens can alter host fitness. Low pathogenic avian influenza virus (LPAIV) infection is thought to have negligible impacts on wild birds; however, effects of infection in free-living birds are largely unstudied. We investigated the extent to which LPAIV infection and shedding were associated with body condition and immune status in free-living mallards (Anas platyrhynchos), a partially migratory key LPAIV host species. We sampled mallards throughout the species\u27 annual autumn LPAIV infection peak, and we classified individuals according to age, sex, and migratory strategy (based on stable hydrogen isotope analysis) when analyzing data on body mass and five indices of immune status. Body mass was similar for LPAIV-infected and noninfected birds. The degree of virus shedding from the cloaca and oropharynx was not associated with body mass. LPAIV infection and shedding were not associated with natural antibody (NAbs) and complement titers (first lines of defense against infections), concentrations of the acute phase protein haptoglobin (Hp), ratios of heterophils to lymphocytes (H:L ratio), and avian influenza virus (AIV)-specific antibody concentrations. NAbs titers were higher in LPAIV-infected males and local (i.e., short distance) migrants than in infected females and distant (i.e., long distance) migrants. Hp concentrations were higher in LPAIV-infected juveniles and females compared to infected adults and males. NAbs, complement, and Hp levels were lower in LPAIV-infected mallards in early autumn. Our study demonstrates weak associations between infection with and shedding of LPAIV and the body condition and immune status of free-living mallards. These results may support the role of mallards as asymptomatic carriers of LPAIV and raise questions about possible coevolution between virus and host
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