53 research outputs found
A remark on Leclerc's Frobenius categories
Leclerc recently studied certain Frobenius categories in connection with
cluster algebra structures on coordinate rings of intersections of opposite
Schubert cells. We show that these categories admit a description as Gorenstein
projective modules over an Iwanaga-Gorenstein ring of virtual dimension at most
two. This is based on a Morita type result for Frobenius categories.Comment: 5 pages, extended abstract for a talk at the Workshop Homological
Bonds between Commutative Algebra and Representation Theory at CRM Barcelona,
February 2015, comments welcom
Actin-Related Protein Arp6 Influences H2A.Z-Dependent and -Independent Gene Expression and Links Ribosomal Protein Genes to Nuclear Pores
Actin-related proteins are ubiquitous components of chromatin remodelers and are conserved from yeast to man. We have examined the role of the budding yeast actin-related protein Arp6 in gene expression, both as a component of the SWR1 complex (SWR-C) and in its absence. We mapped Arp6 binding sites along four yeast chromosomes using chromatin immunoprecipitation from wild-type and swr1 deleted (swr1Δ) cells. We find that a majority of Arp6 binding sites coincide with binding sites of Swr1, the catalytic subunit of SWR-C, and with the histone H2A variant Htz1 (H2A.Z) deposited by SWR-C. However, Arp6 binding detected at centromeres, the promoters of ribosomal protein (RP) genes, and some telomeres is independent of Swr1 and Htz1 deposition. Given that RP genes and telomeres both show association with the nuclear periphery, we monitored the ability of Arp6 to mediate the localization of chromatin to nuclear pores. Arp6 binding is sufficient to shift a randomly positioned locus to nuclear periphery, even in a swr1Δ strain. Arp6 is also necessary for the pore association of its targeted RP promoters possibly through cell cycle-dependent factors. Loss of Arp6, but not Htz1, leads to an up-regulation of these RP genes. In contrast, the pore-association of GAL1 correlates with Htz1 deposition, and loss of Arp6 reduces both GAL1 activation and peripheral localization. We conclude that Arp6 functions both together with the nucleosome remodeler Swr1 and also without it, to mediate Htz1-dependent and Htz1-independent binding of chromatin domains to nuclear pores. This association is shown to have modulating effects on gene expression
Changements globaux en Afrique durant le Quaternaire : passé, présent, futur : volume des résumés = Global change in Africa during Quaternary : past, present, future : volume of abstracts
Growth of carbon nanotubes by fluidized bed catalytic chemical vapor deposition
Multi-walled carbon nanotubes have been produced from H/CH mixtures on Fe/Si02
catalysts by a fluidized bed catalytic chemical vapor deposition process. Various parameters such as the duration of the experiments, the temperature, the H/CH ratio or the amount of metal on the silica support have been examined. The influence of these parameters on both the carbon deposited yield and the morphology of the deposit have been examined. MWNT are preferably produced in the 550-750 °C temperature range on a 2%Fe/SiO (w/w) catalyst in 30 min, with a H/CH ratio of 3. The multi-walled carbon nanotubes remain attached on the silica support.
Rhodium-Catalyzed Hydroformylation of 2-Vinyl- and 3-Vinyl-1-tosylpyrroles As a Convenient Synthetic Route to the Corresponding 2-(1-Tosylpyrrolyl)propanals and Derivatives
Bimetallic catalysis on carbon nanotubes for the selective hydrogenation of cinnamaldehyde
International audienc
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