Electrochemical Method for Direct Deposition of Nanometric Bismuth and Its Electrochemical Properties vs Li

We report that nanometric bismuth can directly be electrodeposited at room temperature without the use of a nanoporous template. The morphology, microstructure, and purity of the as-prepared electrodeposits were characterized by scanning electron microscopy, transmission electron microscopy, and infrared spectroscopy. Typically, well-crystallized nanometer-sized particles of Bi ranging from 10 to 20 nm are obtained. The key to success of such a process lies in the electrochemical coreduction of pyrocatechol violet during the bismuth deposition, which disturbs the electrocrystallization process. As a first possible application, we show that Bi/Cu nanoarchitectured electrodes exhibit interesting rate capabilities when used as electrode material vs Li

Oncogenic gene expression and epigenetic remodeling of cis-regulatory elements in ASXL1-mutant chronic myelomonocytic leukemia

Myeloid neoplasms are clonal hematopoietic stem cell disorders driven by the sequential acquisition of recurrent genetic lesions. Truncating mutations in the chromatin remodeler ASXL1 (ASXL1MT) are associated with a high-risk disease phenotype with increased proliferation, epigenetic therapeutic resistance, and poor survival outcomes. We performed a multi-omics interrogation to define gene expression and chromatin remodeling associated with ASXL1MT in chronic myelomonocytic leukemia (CMML). ASXL1MT are associated with a loss of repressive histone methylation and increase in permissive histone methylation and acetylation in promoter regions. ASXL1MT are further associated with de novo accessibility of distal enhancers binding ETS transcription factors, targeting important leukemogenic driver genes. Chromatin remodeling of promoters and enhancers is strongly associated with gene expression and heterogenous among overexpressed genes. These results provide a comprehensive map of the transcriptome and chromatin landscape of ASXL1MT CMML, forming an important framework for the development of novel therapeutic strategies targeting oncogenic cis interactions

Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe

The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts (GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. (2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A. Reimer, L.C. Reye

Inter-Species Complementation of the Translocon Beta Subunit Requires Only Its Transmembrane Domain

In eukaryotes, proteins enter the secretory pathway through the translocon pore of the endoplasmic reticulum. This protein translocation channel is composed of three major subunits, called Sec61α, β and γ in mammals. Unlike the other subunits, the β subunit is dispensable for translocation and cell viability in all organisms studied. Intriguingly, the knockout of the Sec61β encoding genes results in different phenotypes in different species. Nevertheless, the β subunit shows a high level of sequence homology across species, suggesting the conservation of a biological function that remains ill-defined. To address its cellular roles, we characterized the homolog of Sec61β in the fission yeast Schizosaccharomyces pombe (Sbh1p). Here, we show that the knockout of sbh1+ results in severe cold sensitivity, increased sensitivity to cell-wall stress, and reduced protein secretion at 23°C. Sec61β homologs from Saccharomyces cerevisiae and human complement the knockout of sbh1+ in S. pombe. As in S. cerevisiae, the transmembrane domain (TMD) of S. pombe Sec61β is sufficient to complement the phenotypes resulting from the knockout of the entire encoding gene. Remarkably, the TMD of Sec61β from S. cerevisiae and human also complement the gene knockouts in both yeasts. Together, these observations indicate that the TMD of Sec61β exerts a cellular function that is conserved across species

Inter-Species Complementation of the Translocon Beta Subunit Requires Only Its Transmembrane Domain

In eukaryotes, proteins enter the secretory pathway through the translocon pore of the endoplasmic reticulum. This protein translocation channel is composed of three major subunits, called Sec61α, β and γ in mammals. Unlike the other subunits, the β subunit is dispensable for translocation and cell viability in all organisms studied. Intriguingly, the knockout of the Sec61β encoding genes results in different phenotypes in different species. Nevertheless, the β subunit shows a high level of sequence homology across species, suggesting the conservation of a biological function that remains ill-defined. To address its cellular roles, we characterized the homolog of Sec61β in the fission yeast Schizosaccharomyces pombe (Sbh1p). Here, we show that the knockout of sbh1+ results in severe cold sensitivity, increased sensitivity to cell-wall stress, and reduced protein secretion at 23°C. Sec61β homologs from Saccharomyces cerevisiae and human complement the knockout of sbh1+ in S. pombe. As in S. cerevisiae, the transmembrane domain (TMD) of S. pombe Sec61β is sufficient to complement the phenotypes resulting from the knockout of the entire encoding gene. Remarkably, the TMD of Sec61β from S. cerevisiae and human also complement the gene knockouts in both yeasts. Together, these observations indicate that the TMD of Sec61β exerts a cellular function that is conserved across species

All-sky Medium Energy Gamma-ray Observatory: Exploring the Extreme Multimessenger Universe

The All-sky Medium Energy Gamma-ray Observatory (AMEGO) is a probe class mission concept that will provide essential contributions to multimessenger astrophysics in the late 2020s and beyond. AMEGO combines high sensitivity in the 200 keV to 10 GeV energy range with a wide field of view, good spectral resolution, and polarization sensitivity. Therefore, AMEGO is key in the study of multimessenger astrophysical objects that have unique signatures in the gamma-ray regime, such as neutron star mergers, supernovae, and flaring active galactic nuclei. The order-of-magnitude improvement compared to previous MeV missions also enables discoveries of a wide range of phenomena whose energy output peaks in the relatively unexplored medium-energy gamma-ray band

Modélisation et optimisation de la topologie des réseaux mobiles GSM

L'essor que connaissent les réseaux mobiles a rendu l'automatisation de leur conception incontournable. Cette phase importante du processus de planification des réseaux consiste à localiser des sites sur le terrain, à y positionner des stations et à paramétrer leur configuration. La construction automatique d'un réseau suppose de répondre à des objectifs économiques et techniques. Ceci requiert une modélisation mathématique d'un ensemble de critères pour évaluer la qualité des solutions de réseaux. Jusqu'alors les critères techniques élaborés pour l'optimisation des réseaux sont centrés sur la couverture du réseau, les niveaux d'interférence et l'écoulement du trafic. Des experts radio, qui utilisent des techniques assistées de conception se basant sur la théorie du concept cellulaire, ont évalué les solutions réseaux issues des premières tentatives d'optimisation automatique. Bien que les solutions amélioraient le temps de production et la qualité radio des réseaux, ils ont conclu à la non-faisabilité sur le terrain des solutions proposées faute de structure topologique suffisamment établie. Or la théorie du concept cellulaire définit la topologie du réseau comme un élément central pour garantir la qualité de service et assurer l'extension de la capacité du réseau avec une bonne maîtrise des coûts. Ce mémoire présente plusieurs nouveaux modèles qui intègrent tous les critères géométriques qui s'appuient sur le concept cellulaire théorique et qui visent à structurer le réseau. Ce mémoire met aussi en évidence l'aspect multicritère du problème d'optimisation de la conception des réseaux. Il propose des algorithmes d'optimisation basés sur les approches évolutionnistes.GRENOBLE1-BU Sciences (384212103) / SudocVILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF

Conditional sequential Monte Carlo in high dimensions

The iterated conditional sequential Monte Carlo (i-CSMC) algorithm from Andrieu, Doucet and Holenstein (2010) is an MCMC approach for efficiently sampling from the joint posterior distribution of the T latent states in challenging time-series models, e.g. in non-linear or non-Gaussian statespace models. It is also the main ingredient in particle Gibbs samplers which infer unknown model parameters alongside the latent states. In this work, we first prove that the i-CSMC algorithm suffers from a curse of dimension in the dimension of the states, D: it breaks down unless the number of samples (‘particles’), N, proposed by the algorithm grows exponentially with D. Then, we present a novel ‘local’ version of the algorithm which proposes particles using Gaussian random-walk moves that are suitably scaled with D. We prove that this iterated random-walk conditional sequential Monte Carlo (i-RW-CSMC) algorithm avoids the curse of dimension: for arbitrary N, its acceptance rates and expected squared jumping distance converge to non-trivial limits as D→∞. If T = N = 1, our proposed algorithm reduces to a Metropolis–Hastings or Barker’s algorithm with Gaussian random-walk moves and we recover the well known scaling limits for such algorithms.</p

On the complexity of the dissociation set problems in graphs

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