2,583 research outputs found

    Anti-beta2 glycoprotein I (beta2GPI) antibodies facilitates phagocytosis of apoptotic neutrophils in patients with systemic lupus erythematosus (SLE)

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    BACKGROUND : Increased apoptosis provides a continuous source autoantigens and has been suggested to have a pathogenic role in SLE. We have previously shown patients with SLE have impaired clearance of apoptotic bodies. In this study, we evaluated whether anti-beta2GPI antibodies, a subset of antiphospholipid antibodies, may have an effect on the phagocytosis of apoptotic bodies by macrophages in these patients 
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    Optimal Location of Sources in Transportation Networks

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    We consider the problem of optimizing the locations of source nodes in transportation networks. A reduction of the fraction of surplus nodes induces a glassy transition. In contrast to most constraint satisfaction problems involving discrete variables, our problem involves continuous variables which lead to cavity fields in the form of functions. The one-step replica symmetry breaking (1RSB) solution involves solving a stable distribution of functionals, which is in general infeasible. In this paper, we obtain small closed sets of functional cavity fields and demonstrate how functional recursions are converted to simple recursions of probabilities, which make the 1RSB solution feasible. The physical results in the replica symmetric (RS) and the 1RSB frameworks are thus derived and the stability of the RS and 1RSB solutions are examined.Comment: 38 pages, 18 figure

    Super-exponential Methods Incorporated with Higher-Order Correlations for Deflationary Blind Equalization of MIMO Linear Systems

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    Abstract. The multichannel blind deconvolution of finite-impulse re-sponse (FIR) or infinite-impulse response (IIR) systems is investigated using the multichannel super-exponential deflation methods. In the con-ventional multichannel super-exponential deflation method [4], the so-called “second-order correlation method ” is incorporated in order to estimate the contributions of an extracted source signal to the chan-nel outputs. We propose a new multichannel super-exponential deflation method using higher-order correlations instead of second-order correla-tions to reduce the computational complexity in terms of multiplications and to accelerate the performance of equalization. By computer simula-tions, it is shown that the method of using fourth-order correlations is better than the method of using second-order correlations in a noiseless case or a noisy case.

    Measurement of Lagrangian velocity in fully developed turbulence

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    We have developed a new experimental technique to measure the Lagrangian velocity of tracer particles in a turbulent flow, based on ultrasonic Doppler tracking. This method yields a direct access to the velocity of a single particule at a turbulent Reynolds number Rλ=740R_{\lambda} = 740. Its dynamics is analyzed with two decades of time resolution, below the Lagrangian correlation time. We observe that the Lagrangian velocity spectrum has a Lorentzian form EL(ω)=urms2TL/(1+(TLω)2)E^{L}(\omega) = u_{rms}^{2} T_{L} / (1 + (T_{L}\omega)^{2}), in agreement with a Kolmogorov-like scaling in the inertial range. The probability density function (PDF) of the velocity time increments displays a change of shape from quasi-Gaussian a integral time scale to stretched exponential tails at the smallest time increments. This intermittency, when measured from relative scaling exponents of structure functions, is more pronounced than in the Eulerian framework.Comment: 4 pages, 5 figures. to appear in PR

    Observing two dark accelerators around the Galactic Centre with Fermi Large Area Telescope

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    We report the results from a detailed γ−\gamma-ray investigation in the field of two "dark accelerators", HESS J1745-303 and HESS J1741-302, with 6.96.9 years of data obtained by the Fermi Large Area Telescope. For HESS J1745-303, we found that its MeV-GeV emission is mainly originated from the "Region A" of the TeV feature. Its γ−\gamma-ray spectrum can be modeled with a single power-law with a photon index of Γ∌2.5\Gamma\sim2.5 from few hundreds MeV to TeV. Moreover, an elongated feature, which extends from "Region A" toward northwest for ∌1.3∘\sim1.3^{\circ}, is discovered for the first time. The orientation of this feature is similar to that of a large scale atomic/molecular gas distribution. For HESS J1741-302, our analysis does not yield any MeV-GeV counterpart for this unidentified TeV source. On the other hand, we have detected a new point source, Fermi J1740.1-3013, serendipitously. Its spectrum is apparently curved which resembles that of a γ−\gamma-ray pulsar. This makes it possibly associated with PSR B1737-20 or PSR J1739-3023.Comment: 11 pages, 7 figures, 2 tables, accepted for publication in MNRA

    Nonlinear Bias and the Convective Fisher Equation

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    We combine random walks, growth and decay, and convection, in a Monte Carlo simulation to model 1D interface dynamics with fluctuations. The continuum limit corresponds to the deterministic Fisher equation with convection. We find qualitatively the same type of asymmetry, as well as velocity difference, for interface profiles moving in opposite directions. However a transition apparent in the mean-field (continuum) limit is not found in the Monte Carlo simulation.Comment: 2.5 pages (texed) with 4 postscript figures, TeX 3.14t

    New methodology for specific inhalation challenges with occupational agents

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    <p>Abstract</p> <p>Background</p> <p>Inhalation challenges are used for diagnosing occupational asthma (OA). The initial methodology consisted of a "realistic" exposure without monitoring nor controlling exposure. Our aim was to design an equipment, called the GenaSIC, that allows the generation of various agents regardless of the formulation and to assess the feasibility of its use in patients investigated for OA.</p> <p>Results</p> <p>GenaSIC can generate lactose, flour, malt, isocyanates, formaldehyde and N-butyl acetate with precise and fairly stable concentrations. Using N-butyl-acetate as a control agent and real time measurement, we show that normal breathing has a negligible effect on the concentration. We exposed forty-four different subjects to a control agent and/or to a suspected occupational agent. Nineteen of the subjects were only exposed to N-butyl acetate as a control agent without experiencing any significant irritant effect (no significant changes in spirometry thereafter). Eight subjects who were exposed to both N-butyl acetate and formaldehyde did not show significant reactions. Seven subjects were exposed to dry particles (flour in six instances, malt in the other) and five showed immediate asthmatic reactions which changes in FEV1 from 20% to a maximum of 28%. Finally, ten subjects were exposed to isocyanates, four of whom showed a positive reaction, including one subject with immediate maximum changes in FEV1 of 22%.</p> <p>Conclusion</p> <p>GenaSIC offers the possibility of reliable and safe exposures to dry particles, formaldehyde and isocyanates in the investigation of OA.</p

    Density mismatch in thin diblock copolymer films

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    Thin films of diblock copolymer subject to gravitational field are simulated by means of a cell dynamical system model. The difference in density of the two sides of the molecule and the presence of the field causes the formation of lamellar patterns with orientation parallel to the confining walls even when they are neutral. The concentration profile of those films is analyzed in the weak segregation regime and a functional form for the profile is proposed.Comment: 9 pages and 8 figures. Needs EPSF macros. Submitted to PR

    Immunohistochemical characterization of feline lymphoplasmacytic anterior uveitis

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    OBJECTIVE: To characterize the immune cells present in different forms of feline anterior uveitis. SAMPLES: Eyes were obtained from 49 cats diagnosed with chronic idiopathic lymphoplasmacytic anterior uveitis, 7 cats with feline infectious peritonitis (FIP), and 9 cats euthanized for nonocular disease. METHODS: H&E sections were scored on the level of infiltrate in the anterior uvea. Immunohistochemistry was performed for FoxP3, CD3, and IL-17A, and positive cells were quantified in multiple images of each sample. A generalized estimating equation tested for an association between the level of inflammation and the prevalence of these cell types. RESULTS: Cells stained positive for IL-17A in idiopathic uveitis but not in FIP samples. We found significantly fewer FoxP3+and CD3+cells in low-grade compared with high-grade inflammation in idiopathic uveitis or FIP samples (P values all <.005), but no difference between FIP and high-grade samples. CONCLUSIONS: Idiopathic, but not FIP-associated, uveitis appears to have Th17 cell involvement. The numbers of FoxP3+and CD3+T-cells present appear directly correlated; thus, the severity of disease does not appear directly determined by the numbers of regulatory cells

    Unsupervised Bayesian linear unmixing of gene expression microarrays

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    Background: This paper introduces a new constrained model and the corresponding algorithm, called unsupervised Bayesian linear unmixing (uBLU), to identify biological signatures from high dimensional assays like gene expression microarrays. The basis for uBLU is a Bayesian model for the data samples which are represented as an additive mixture of random positive gene signatures, called factors, with random positive mixing coefficients, called factor scores, that specify the relative contribution of each signature to a specific sample. The particularity of the proposed method is that uBLU constrains the factor loadings to be non-negative and the factor scores to be probability distributions over the factors. Furthermore, it also provides estimates of the number of factors. A Gibbs sampling strategy is adopted here to generate random samples according to the posterior distribution of the factors, factor scores, and number of factors. These samples are then used to estimate all the unknown parameters. Results: Firstly, the proposed uBLU method is applied to several simulated datasets with known ground truth and compared with previous factor decomposition methods, such as principal component analysis (PCA), non negative matrix factorization (NMF), Bayesian factor regression modeling (BFRM), and the gradient-based algorithm for general matrix factorization (GB-GMF). Secondly, we illustrate the application of uBLU on a real time-evolving gene expression dataset from a recent viral challenge study in which individuals have been inoculated with influenza A/H3N2/Wisconsin. We show that the uBLU method significantly outperforms the other methods on the simulated and real data sets considered here. Conclusions: The results obtained on synthetic and real data illustrate the accuracy of the proposed uBLU method when compared to other factor decomposition methods from the literature (PCA, NMF, BFRM, and GB-GMF). The uBLU method identifies an inflammatory component closely associated with clinical symptom scores collected during the study. Using a constrained model allows recovery of all the inflammatory genes in a single factor
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