713 research outputs found
Aortic remodelling induced by obstructive apneas is normalized with mesenchymal stem cells infusion
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
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 âRisco de vida na perspectiva dos usuĂĄrios do Serviço de Atendimento MĂłvel de UrgĂȘncia de Porto Alegre (SAMU) â subsĂdios para a gestĂŁo do serviçoâ, 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
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
Because of an old quasar APM 08279+5255 at , 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
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
Many dark energy models fail to pass the cosmic age test because of the old
quasar APM 08279+5255 at redshift , the CDM 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 level under the current observational
constraints.Comment: 12 pages, 5 figures; typos corrected; version for publication in
SCIENCE CHINA Physics, Mechanics & Astronom
- âŠ