713 research outputs found

    Aortic remodelling induced by obstructive apneas is normalized with mesenchymal stem cells infusion

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    Obstructive sleep apnea syndrome (OSA) promotes aortic dilatation, increased stiffness and accelerated atherosclerosis, but the mechanisms of vascular remodelling are not known. We aimed to assess vascular remodelling, its mechanisms, and the effect of mesenchymal stem cells (MSC) infusions in a clinically relevant rat model of chronic OSA involving recurrent airway obstructions leading thoracic pressure swings and intermittent hypoxia/hypercapnia (OSA-rats). Another group of rats were placed in the same setup without air obstructions (Sham-rats) and were considered controls. Our study demonstrates that chronic, non-invasive repetitive airway obstructions mimicking OSA promote remarkable structural changes of the descending thoracic aorta such as eccentric aortic hypertrophy due to an increased wall thickness and lumen diameter, an increase in the number of elastin fibers which, in contrast, get ruptured, but no changes in tunica media fibrosis. As putative molecular mechanisms of the OSA-induced vascular changes we identified an increase in reactive oxygen species and renin-angiotensin system markers and an imbalance in oxide nitric synthesis. Our results also indicate that MSC infusion blunts the OSA-related vascular changes, most probably due to their anti-inflammatory properties

    Oficinas de primeiros socorros: relato de experiĂȘncia

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    Este relato de experiĂȘncia Ă© resultado do processo de construção de oficinas de primeiros socorros, oferecidas aos moradores do bairro Cavalhada, da cidade de Porto Alegre, Rio Grande do Sul. As oficinas resultaram da preocupação dos pesquisadores, envolvidos no projeto “Risco de vida na perspectiva dos usuĂĄrios do Serviço de Atendimento MĂłvel de UrgĂȘncia de Porto Alegre (SAMU) – subsĂ­dios para a gestĂŁo do serviço”, em interferir, de forma mais dinĂąmica, na realidade estudada. Ao produzirmos este relato, buscamos fornecer subsĂ­dios para experiĂȘncias no ensino de primeiros socorros

    Dissipationless Mergers of Elliptical Galaxies and the Evolution of the Fundamental Plane

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    We carry out numerical simulations of dissipationless major mergers of elliptical galaxies using initial galaxy models that consist of a dark matter halo and a stellar bulge with properties consistent with the observed fundamental plane. By varying the density profile of the dark matter halo (standard NFW versus adiabatically contracted NFW), the global stellar to dark matter mass ratio, and the orbit of the merging galaxies, we are able to assess the impact of each of these factors on the structure of the merger remnant. Our results indicate that the properties of the remnant bulge depend primarily on the angular momentum and energy of the orbit; for a cosmologically motivated orbit, the effective radius and velocity dispersion of the remnant bulge remain approximately on the fundamental plane. This indicates that the observed properties of elliptical galaxies are consistent with significant growth via late dissipationless mergers. We also find that the dark matter fraction within the effective radius of our remnants increases after the merger, consistent with the hypothesis that the tilt of the fundamental plane from the virial theorem is due to a varying dark matter fraction as a function of galaxy mass.Comment: 14 pages, 6 figures; MNRAS, in press. Minor revisions, results from an additional simulation adde

    Cosmic age problem revisited in the holographic dark energy model

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    Because of an old quasar APM 08279+5255 at z=3.91z=3.91, some dark energy models face the challenge of the cosmic age problem. It has been shown by Wei and Zhang [Phys. Rev. D {\bf 76}, 063003 (2007)] that the holographic dark energy model is also troubled with such a cosmic age problem. In order to accommodate this old quasar and solve the age problem, we propose in this Letter to consider the interacting holographic dark energy in a non-flat universe. We show that the cosmic age problem can be eliminated when the interaction and spatial curvature are both involved in the holographic dark energy model.Comment: 7 pages, 3 figures; v2: typos corrected, version for publication in Phys.Lett.B; v3: typos in eqs (17,18) correcte

    Cellular responses of Candida albicans to phagocytosis and the extracellular activities of neutrophils are critical to counteract carbohydrate starvation, oxidative and nitrosative stress

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    Acknowledgments We thank Alexander Johnson (yhb1D/D), Karl Kuchler (sodD/D mutants), Janet Quinn (hog1D/D, hog1/cap1D/D, trx1D/D) and Peter Staib (ssu1D/D) for providing mutant strains. We acknowledge helpful discussions with our colleagues from the Microbial Pathogenicity Mechanisms Department, Fungal Septomics and the Microbial Biochemistry and Physiology Research Group at the Hans Knošll Institute (HKI), specially Ilse D. Jacobsen, Duncan Wilson, Sascha Brunke, Lydia Kasper, Franziska Gerwien, SeaŽna Duggan, Katrin Haupt, Kerstin Hušnniger, and Matthias Brock, as well as from our partners in the FINSysB Network. Author Contributions Conceived and designed the experiments: PM HW IMB AJPB OK BH. Performed the experiments: PM CD HW. Analyzed the data: PM HW IMB AJPB OK BH. Wrote the paper: PM HW OK AJPB BH.Peer reviewedPublisher PD

    Interacting model of new agegraphic dark energy: observational constraints and age problem

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    Many dark energy models fail to pass the cosmic age test because of the old quasar APM 08279+5255 at redshift z=3.91z=3.91, the Λ\LambdaCDM model and holographic dark energy models being no exception. In this paper, we focus on the topic of age problem in the new agegraphic dark energy (NADE) model. We determine the age of the universe in the NADE model by fitting the observational data, including type Ia supernovae (SNIa), baryon acoustic oscillations (BAO) and the cosmic microwave background (CMB). We find that the NADE model also faces the challenge of the age problem caused by the old quasar APM 08279+5255. In order to overcome such a difficulty, we consider the possible interaction between dark energy and dark matter. We show that this quasar can be successfully accommodated in the interacting new agegraphic dark energy (INADE) model at the 2σ2\sigma level under the current observational constraints.Comment: 12 pages, 5 figures; typos corrected; version for publication in SCIENCE CHINA Physics, Mechanics & Astronom
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