19 research outputs found

    Design, Modeling and Evaluation of a 2.4GHz FHSS Communications System for NarcisSat

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    Communication subsystems generally consume the majority of power and a significant fraction of mass and volume for picosatellites, and thus their design is critical to the overall satellite and mission plans. The available data bandwidth defines the types of payloads that can be accommodated. Until now, most CubeSat designs have used the 2m (145MHz) and 70cm (437MHz) bands. We present simulation and experimental measurements of a commercial, off-theshelf (COTS) spread spectrum 2.4GHz system that is incorporated on NarcisSat, a CubeSat scheduled for launch in late 2003. In the 2.4GHz band, patch antennas instead of monopoles are suitable, eliminating the need to deploy antennas on orbit. With the system presented here, data rates of up to 115kbps are possible, facilitating new kinds of more data intensive payloads than previously possible in CubeSats. Spread spectrum is well suited for multiple CubeSat deployment and handles ground-based noise better than narrowband communications. We also address the attitude control subsystem and ground station requirements of this system

    Superintegrable systems with spin and second-order integrals of motion

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    We investigate a quantum nonrelativistic system describing the interaction of two particles with spin 1/2 and spin 0, respectively. We assume that the Hamiltonian is rotationally invariant and parity conserving and identify all such systems which allow additional integrals of motion that are second order matrix polynomials in the momenta. These integrals are assumed to be scalars, pseudoscalars, vectors or axial vectors. Among the superintegrable systems obtained, we mention a generalization of the Coulomb potential with scalar potential V0=αr+328r2V_0=\frac{\alpha}{r}+\frac{3\hbar^2}{8r^2} and spin orbital one V1=2r2V_1=\frac{\hbar}{2r^2}.Comment: 32 page

    Antineutrophil Cytoplasmic Antibodies Associated With Infective Endocarditis

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    International audienceTo determine the prevalence of antineutrophil cytoplasmic antibodies (ANCA) in patients with infective endocarditis (IE) in internal medicine; and to compare clinical and biochemical features and outcome between patients exhibiting IE with and without ANCA.Fifty consecutive patients with IE underwent ANCA testing. The medical records of these patients were reviewed.Of the 50 patients with IE, 12 exhibited ANCA (24%). ANCA-positive patients with IE exhibited: longer duration between the onset of first symptoms and IE diagnosis (P = 0.02); and more frequently: weight loss (P = 0.017) and renal impairment (P = 0.08), lower levels of C-reactive protein (P = 0.0009) and serum albumin (P = 0.0032), involvement of both aortic and mitral valves (P = 0.009), and longer hospital stay (P = 0.016). Under multivariate analysis, significant factors for ANCA-associated IE were: longer hospital stay (P = 0.004), lower level of serum albumin (P = 0.02), and multiple valve involvement (P = 0.04). Mortality rate was 25% in ANCA patients; death was because of IE complications in all these patients.Our study identifies a high prevalence of ANCA in unselected patients with IE in internal medicine (24%). Our findings further underscore that ANCA may be associated with a subacute form of IE leading to multiple valve involvement and more frequent renal impairment. Because death was due to IE complications in all patients, our data suggest that aggressive therapy may be required to improve such patients’ outcome

    Peripheral denervation participates in heterotopic ossification in a spinal cord injury model

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    We previously reported the development of a new acquired neurogenic HO (NHO) mouse model, combining spinal cord transection (SCI) and chemical muscle injury. Pathological mechanisms responsible for ectopic osteogenesis after central neurological damage are still to be elucidated. In this study, we first hypothesized that peripheral nervous system (PNS) might convey pathological signals from injured spinal cord to muscles in NHO mouse model. Secondly, we sought to determine whether SCI could lead to intramuscular modifications of BMP2 signaling pathways. Twenty one C57Bl6 mice were included in this protocol. Bilateral cardiotoxin (CTX) injection in hamstring muscles was associated with a two-stage surgical procedure, combining thoracic SCI with unilateral peripheral denervation. Volumes of HO (Bone Volume, BV) were measured 28 days after surgery using micro-computed tomography imaging techniques and histological analyses were made to confirm intramuscular osteogenesis. Volume comparisons were conducted between right and left hind limb of each animal, using a Wilcoxon signed rank test. Quantitative polymerase chain reaction (qPCR) was performed to explore intra muscular expression of BMP2, Alk3 and Id1. Nineteen mice survive the complete SCI and peripheral denervation procedure. When CTX injections were done right after surgery (n = 7), bilateral HO were detected in all animals after 28 days. Micro-CT measurements showed significantly increased BV in denervated paws (1.47 mm3 +/- 0.5) compared to contralateral sides (0.56 mm3 +/-0.4), p = 0.03. When peripheral denervation and CTX injections were performed after sham SCI surgery (n = 6), bilateral HO were present in three mice at day 28. Quantitative PCR analyses showed no changes in intra muscular BMP2 expression after SCI as compared to control mice (shamSCI). Peripheral denervation can be reliably added to spinal cord transection in NHO mouse model. This new experimental design confirms that neuro inflammatory mechanisms induced by central or peripheral nervous system injury plays a key role in triggering ectopic osteogenesis

    OpenProt: a more comprehensive guide to explore eukaryotic coding potential and proteomes

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    International audienceAdvances in proteomics and sequencing have highlighted many non-annotated open reading frames (ORFs) in eukaryotic genomes. Genome annotations, cornerstones of today's research, mostly rely on protein prior knowledge and on ab initio prediction algorithms. Such algorithms notably enforce an arbitrary criterion of one coding sequence (CDS) per transcript, leading to a substantial underestimation of the coding potential of eukaryotes. Here, we present OpenProt, the first database fully endorsing a polycistronic model of eukaryotic genomes to date. OpenProt contains all possible ORFs longer than 30 codons across 10 species, and cumulates supporting evidence such as protein conservation, translation and expression. OpenProt annotates all known proteins (RefProts), novel predicted isoforms (Isoforms) and novel predicted proteins from alternative ORFs (AltProts). It incorporates cutting-edge algorithms to evaluate protein orthology and re-interrogate publicly available ribosome profiling and mass spectrometry datasets, supporting the annotation of thousands of predicted ORFs. The constantly growing database currently cumulates evidence from 87 ribosome profiling and 114 mass spectrometry studies from several species, tissues and cell lines. All data is freely available and downloadable from a web platform (www.openprot.org) supporting a genome browser and advanced queries for each species. Thus, OpenProt enables a more comprehensive landscape of eukaryotic genomes' coding potential

    Identification of Mitofusin 1 and Complement Component 1q Subcomponent Binding Protein as Mitochondrial Targets in Systemic Lupus Erythematosus

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    53 páginas, 4 figuras, 2 tablasObjective: Mitochondria are organelles that exhibit several bacterial features, such as a double-stranded genome with hypomethylated CpG islands, formylated proteins, and cardiolipin-containing membranes. In systemic lupus erythematosus (SLE), mitochondria and their inner components are released into the extracellular space, potentially eliciting a proinflammatory response from the immune system. While cardiolipin and mitochondrial DNA and RNA are confirmed targets of autoantibodies, other antigenic mitochondrial proteins in SLE remain to be identified. The present study was undertaken to characterize the protein repertoire recognized by antimitochondrial antibodies (AMAs) in patients with SLE. Methods: Using shotgun proteomic profiling, we identified 1,345 proteins, 431 of which were associated with the mitochondrial proteome. Immunoreactivities to several of these candidate proteins were assessed in serum samples from a local cohort (n = 30 healthy donors and 87 patients with SLE) using enzyme-linked immunosorbent assay, and further analyzed for associations with demographic and disease characteristics. Results: We determined that IgG antibodies to the complement component C1q binding protein were significantly elevated in the patients with SLE (P = 0.049) and were also associated with lupus anticoagulant positivity (P = 0.049). Elevated levels of IgG antibodies against mitochondrial protein mitofusin 1 (MFN-1) were promising predictors of SLE diagnosis in our cohort (adjusted odds ratio 2.99 [95% confidence interval 1.39-6.43], P = 0.0044). Moreover, increased levels of anti-MFN-1 were associated with the presence of antiphospholipids (P = 0.011) and anti-double-stranded DNA (P = 0.0005). Conclusion: In this study, we characterized the mitochondrial repertoire targeted by AMAs in the setting of SLE. Our results indicate that autoantibodies can recognize secreted and/or surface proteins of mitochondrial origin. Profiling of the AMA repertoire in large prospective cohorts may improve our knowledge of mitochondrial biomarkers and their usefulness for patient stratification.Supported by the Arthritis Society (grant 225638 to Dr. Fortin), the Canadian Institutes of Health Research (CIHR) (CIHR Foundation grant to Dr. Boilard and CIHR operating grant MOP-97916). Dr. Becker's work was supported by the Fonds de Recherche en Sante du Quebec (grant 282342) and the Arthritis Society (grant TGP-18-0257). Dr. Rubio's work was supported by the Secretaría de Estado de Investigación, Desarrollo e Innovación (grant BFU2017-84264-P) and by the Fundación Ramón Areces. Dr. Poirier's work was supported by the CIHR. Dr. Boilard's work was supported by the Fonds de Recherche en Sante du Quebec and the Canadian Donation and Transplantation Research ProgramPeer reviewe

    L’autel-reliquaire de Sainte-Marie de l’Aventin à Rome, exemple de la “renovatio” clunisienne

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    Nella chiesa di S. Maria in Aventino a Roma, si trova un altare reliquario relativamente raro per quanto riguarda la decorazione e le iscrizioni. Le datazioni proposte dagli storici vanno dal VI secolo a XII secolo. Applicando un metodologia comparata basata sulla storia, la storia dell'arte, la paleografia e l'epigrafia, si giunge alla conclusione che l'altare risale al secolo X, o al principio del secolo XI. Esso presenta un gran numero di elementi grafici ed ornamentali ispirati all'antichità classica. Realizzato per un monastero cluniacense a Roma, l'altare rappresenta la tendenza dell'ordine cluniacense a volersi ispirare alla Roma dell'inizio del Cristianesimo, dimostrando al contempo, l'importanza dell'ideale di "renovatio" nella produzione artistica dell'epoca
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