613 research outputs found

    A class of cubic Rauzy Fractals

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    In this paper, we study arithmetical and topological properties for a class of Rauzy fractals Ra{\mathcal R}_a given by the polynomial x3−ax2+x−1x^3- ax^2+x-1 where a≥2a \geq 2 is an integer. In particular, we prove the number of neighbors of Ra{\mathcal R}_a in the periodic tiling is equal to 88. We also give explicitly an automaton that generates the boundary of Ra{\mathcal R}_a. As a consequence, we prove that R2{\mathcal R}_2 is homeomorphic to a topological disk

    Vaccine-induced skewing of T cell responses protects against Chikungunya virus disease

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    Chikungunya virus (CHIKV) infections can cause severe and debilitating joint and muscular pain that can be long lasting. Current CHIKV vaccines under development rely on the generation of neutralizing antibodies for protection; however, the role of T cells in controlling CHIKV infection and disease is still unclear. Using an overlapping peptide library, we identified the CHIKV-specific T cell receptor epitopes recognized in C57BL/6 infected mice at 7 and 14 days post-infection. A fusion protein containing peptides 451, 416, a small region of nsP4, peptide 47, and an HA tag (CHKVf5) was expressed using adenovirus and cytomegalovirus-vectored vaccines. Mice vaccinated with CHKVf5 elicited robust T cell responses to higher levels than normally observed following CHIKV infection, but the vaccine vectors did not elicit neutralizing antibodies. CHKVf5-vaccinated mice had significantly reduced infectious viral load when challenged by intramuscular CHIKV injection. Depletion of both CD

    Generalized quasiperiodic Rauzy tilings

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    We present a geometrical description of new canonical dd-dimensional codimension one quasiperiodic tilings based on generalized Fibonacci sequences. These tilings are made up of rhombi in 2d and rhombohedra in 3d as the usual Penrose and icosahedral tilings. Thanks to a natural indexing of the sites according to their local environment, we easily write down, for any approximant, the sites coordinates, the connectivity matrix and we compute the structure factor.Comment: 11 pages, 3 EPS figures, final version with minor change

    Rétinopathie diabétique : quand opérer ?

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    Etiology and factors associated with pneumonia in children under 5 years of age in Mali: A prospective case-control study

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    Background: There are very limited data on children with pneumonia in Mali. The objective was to assess the etiology and factors associated with community-acquired pneumonia in hospitalized children <5 years of age in Mali. Methods: A prospective hospital-based case-control study

    Selective Survival and Maturation of Adult-Born Dentate Granule Cells Expressing the Immediate Early Gene Arc/Arg3.1

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    Progenitor cells in the adult dentate gyrus provide a constant supply of neuronal precursors, yet only a small fraction of these cells survive and develop into mature dentate granule cells (DGCs). A major challenge of current research is thus to understand the stringent selection process that governs the maturation and functional integration of adult-born DGCs. In mature DGCs, high-frequency stimulation (HFS) of the perforant path input elicits robust expression of the immediate early gene Arc/Arg3.1, trafficking of its mRNA to dendrites, and local synthesis of the protein necessary for consolidation of long-term potentiation (LTP). Given the synaptic commitment inherent in LTP consolidation, we considered that HFS-evoked expression of Arc could be used to timemap the functional integration of newborn DGCs. Dividing cells were birthmarked by BrdU-labeling at 1, 7, 14, 21, or 28 days prior to induction of LTP and expression of Arc was examined by confocal microscopy. Contrary to expectation, LTP did not induce Arc expression in newborn cells at any age, suggesting they might be refractory to synaptically-evoked Arc expression for at least one month. Importantly, however, spontaneous expression of Arc was detected in BrdU-labeled cells and strongly associated with the survival and maturation of NeuN-positive DGCs. Moreover, Arc expression at the earliest ages (1 and 7 days), clearly precedes the formation of glutamatergic synapses on new neurons. These results suggest an unexpected early role for Arc in adult-born DGCs, distinct from its functions in LTP, LTD, and homeostatic synaptic plasticity

    Paravalvular regurgitation after transcatheter aortic valve replacement: incidence, quantification, and prognostic impact

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    Transcatheter aortic valve replacement (TAVR) is the standard of care in aortic stenosis with results comparable to surgical aortic valve replacement. However, paravalvular regurgitation (PVR) is more common after TAVR. With the alteration of devices and implantation techniques, the incidence of moderate or more PVR has declined. Mild PVR is still common in around 30% of TAVR patients in low-risk trials. Progression of AS causes myocardial hypertrophy and varying degrees of diastolic dysfunction which may cause heart failure even in combination with small volumes of PVR. Any degree of PVR is associated with an increased risk of overall and cardiovascular mortality. Predictors of PVR are annular eccentricity, severe calcification of the aortic valve, bicuspid aortic valves, and type of prosthesis where balloon-expandable devices are associated with less PVR. PVR is diagnosed using echocardiography, aortic angiogram with or without videodensitometry, haemodynamic parameters, or cardiac magnetic resonance. PVR can be treated using post-dilation, interventional treatment using a vascular plug, or implantation of a second device. Successful post-dilation depends on balloon size which should at least be equal to or >95% of the mean annulus diameter. Implantation of a second device to reduce PVR is successful in ∼90% of cases, either through lengthening of the sealing skirt in case of inadequate position or through further expansion of the index device. Implantation of a vascular plug can successfully reduce PVR and reduce mortality
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