6,556 research outputs found

    Characterisation of exacerbation risk and exacerbator phenotypes in the POET-COPD trial

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    Background: Data examining the characteristics of patients with frequent exacerbations of chronic obstructive pulmonary disease (COPD) and associated hospitalisations and mortality are scarce. Methods: Post-hoc analysis of the Prevention Of Exacerbations with Tiotropium in COPD (POET-COPD) trial, targeting exacerbations as the primary endpoint. Patients were classified as non-, infrequent, and frequent exacerbators (0, 1, or >= 2 exacerbations during study treatment), irrespective of study treatment. A multivariate Cox regression model assessed the effect of covariates on time to first exacerbation. Results: In total, 7376 patients were included in the analysis: 63.5% non-exacerbators, 22.9% infrequent, 13.6% frequent exacerbators. Factors significantly associated with exacerbation risk were age, sex, body mass index, COPD duration and severity, smoking history, baseline inhaled corticosteroid use, and preceding antibiotic or systemic corticosteroid courses. Frequent exacerbators had greater severity and duration of COPD, received more pulmonary medication, and >= 2 systemic corticosteroid or antibiotic courses in the preceding year, and were more likely to be female and ex-smokers. The small proportion of frequent exacerbators (13.6%) accounted for 56.6% of exacerbation-related hospitalisations, which, overall, were associated with a three-fold increase in mortality. Conclusion: The frequent exacerbator phenotype was closely associated with exacerbation-related hospitalisations, and exacerbation-related hospitalisations were associated with poorer surviva

    Moisture Control, Inoculant and Particle Size in Tropical Grass Silages

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    Decreased fermentation and spoilage losses with improved aerobic stability during feed out can be accomplished by several strategies, such as wilting, addition of microbial additives and moisture absorbents. Particle size reduction may increase bulk density and improve the fermentation. The objective of this trial was to evaluate the effects of particle size, moisture content and a microbial additive on chemical-physical parameters and losses in silages made from Tanzania grass

    Boundary Term in Metric f(R) Gravity: Field Equations in the Metric Formalism

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    The main goal of this paper is to get in a straightforward form the field equations in metric f(R) gravity, using elementary variational principles and adding a boundary term in the action, instead of the usual treatment in an equivalent scalar-tensor approach. We start with a brief review of the Einstein-Hilbert action, together with the Gibbons-York-Hawking boundary term, which is mentioned in some literature, but is generally missing. Next we present in detail the field equations in metric f(R) gravity, including the discussion about boundaries, and we compare with the Gibbons-York-Hawking term in General Relativity. We notice that this boundary term is necessary in order to have a well defined extremal action principle under metric variation.Comment: 12 pages, title changes by referee recommendation. Accepted for publication in General Relativity and Gravitation. Matches with the accepted versio

    Elastic constant dishomogeneity and Q2Q^2 dependence of the broadening of the dynamical structure factor in disordered systems

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    We propose an explanation for the quadratic dependence on the momentum QQ, of the broadening of the acoustic excitation peak recently found in the study of the dynamic structure factor of many real and simulated glasses. We ascribe the observed Q2Q^2 law to the spatial fluctuations of the local wavelength of the collective vibrational modes, in turn produced by the dishomegeneity of the inter-particle elastic constants. This explanation is analitically shown to hold for 1-dimensional disordered chains and satisfatorily numerically tested in both 1 and 3 dimensions.Comment: 4 pages, RevTeX, 5 postscript figure

    Ab-initio calculations and ellipsometry measurements of the optical properties of the layered semiconductor In4Se3

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    In this work, we present a thorough study of the optical properties of the layered orthorhombic compoundIn4Se3. The dielectric function—real and imaginary parts, the complex refraction index, the reflectivity, theabsorption coefficient, and the conductivity of In4Se3 were calculated with the inclusion of the spin-orbitinteraction, using an ab initio FP-LAPW method based on DFT. Also, generalized ellipsometry was employedfor more precise measurement of the anisotropic dielectric functions for polarization along crystal a, b, and caxes of orthorhombic absorbing In4Se3 single crystals cut approximately parallel to (100) at photon energiesfrom 0.76 to 3.1 eV. Our experimental results show a good agreement with our calculations. We discuss thelocation and nature of the main optical peaks appearing in the spectra. The obtained optical functions displaya rather anisotropic behavior, mainly in the infrared-visible region. Our results seem to be predictive to a highextension, given the scarce experimental information about its optical properties.Fil: Makinistian, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina. Universidad Nacional de Entre Rios; ArgentinaFil: Albanesi, Eduardo Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina. Universidad Nacional de Entre Rios; ArgentinaFil: Gonzalez Lemus, Nasly Vanessa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina. Universidad Nacional de Entre Rios; ArgentinaFil: Petukhov, A. G.. South Dakota School of Mines; Estados UnidosFil: Schmidt, D.. University Of Nebraska; Estados UnidosFil: Schubert, E.. University Of Nebraska; Estados UnidosFil: Schubert, M.. University Of Nebraska; Estados UnidosFil: Losovyj, Ya. Louisiana State University; Estados UnidosFil: Galiy, P.. Ivan Franko National University of Lviv; UcraniaFil: Dowben, P.. University Of Nebraska; Estados Unido

    Single-nucleus multi-omics of human stem cell-derived islets identifies deficiencies in lineage specification

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    Insulin-producing β cells created from human pluripotent stem cells have potential as a therapy for insulin-dependent diabetes, but human pluripotent stem cell-derived islets (SC-islets) still differ from their in vivo counterparts. To better understand the state of cell types within SC-islets and identify lineage specification deficiencies, we used single-nucleus multi-omic sequencing to analyse chromatin accessibility and transcriptional profiles of SC-islets and primary human islets. Here we provide an analysis that enabled the derivation of gene lists and activity for identifying each SC-islet cell type compared with primary islets. Within SC-islets, we found that the difference between β cells and awry enterochromaffin-like cells is a gradient of cell states rather than a stark difference in identity. Furthermore, transplantation of SC-islets in vivo improved cellular identities overtime, while long-term in vitro culture did not. Collectively, our results highlight the importance of chromatin and transcriptional landscapes during islet cell specification and maturation
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