232 research outputs found

    The HyperBagGraph DataEdron: An Enriched Browsing Experience of Multimedia Datasets

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    Traditional verbatim browsers give back information in a linear way according to a ranking performed by a search engine that may not be optimal for the surfer. The latter may need to assess the pertinence of the information retrieved, particularly when sâ‹…\cdothe wants to explore other facets of a multi-facetted information space. For instance, in a multimedia dataset different facets such as keywords, authors, publication category, organisations and figures can be of interest. The facet simultaneous visualisation can help to gain insights on the information retrieved and call for further searches. Facets are co-occurence networks, modeled by HyperBag-Graphs -- families of multisets -- and are in fact linked not only to the publication itself, but to any chosen reference. These references allow to navigate inside the dataset and perform visual queries. We explore here the case of scientific publications based on Arxiv searches.Comment: Extension of the hypergraph framework shortly presented in arXiv:1809.00164 (possible small overlaps); use the theoretical framework of hb-graphs presented in arXiv:1809.0019

    Elaboration et étude des propriétés physico-chimiques de nouveaux composés magnétiques

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    Ce travail a été partagé en deux parties dédiées à (i) l'élaboration de sels de C60 (KC60) et la caractérisation de leurs propriétés physico-chimiques ; et (ii) à l'étude et l'analyse des propriétés magnétiques de dérivés du Bleu de Prusse. Notre but a été d'apporter des réponses expérimentales et théoriques aux résultats contradictoires publiés sur ces deux sujets. Pour cela, un effort particulier a été porté sur la maîtrise des conditions de synthèse du KC60 qui nous a permis de contrôler la nature de l'état fondamental. Cette étude a par ailleurs mis en évidence le rôle clef de l'insertion d'atome d'argon sur les propriétés électroniques de ces composés. En ce qui concerne les dérivés du Bleu de Prusse, nous avons montré que l'ordre magnétique observé à basse température est de nature ferrimagnétique et que cette phase magnétique possède une anisotropie magnétique originale induite dans ces matériaux par l'unité Mo(CN)74-This work was divided in two parts dedicated to (i) the development of KC60 salts and the characterization of their physical properties; and (ii) the study and the analysis of the magnetic properties of Prussian Blue-like phases. Our goal was to bring experimental and theoretical answers to the contradictory results published on these two subjects. A particular effort was dedicated to the control of the conditions of KC60 synthesis which enabled us to control the nature of the fundamental state. This study in addition highlighted the important role of argon atoms insertion on the electronic properties of these compounds. With regard to the Prussian Blue-like phases, we showed that the magnetic order observed at low temperature is ferrimagnetic and this magnetic phase has an original magnetic anisotropy induced in these materials by the Mo(CN)74- unit

    Dehydration and decomposition behavior of the NaH2(PO4)0,48AsO4)0,52.H2O compound in the temperature range from 253 K to 333 K.

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    The mixed compound NaH2(PO4)0.48(AsO4)0.52.H2O, which has been examined by Raman spectroscopy, XRD powder and dielectric, exhibits solid–solid phase transitions and one reversible solid–liquid phase transition. Besides, the investigation of dehydration behavior of sodium dihydrogenate phosphate-arsenate monohydrate was undertaken in a temperature range from 253 K to 333 K. The onset temperature of dehydration was determined from changes in ionic conductivity and X-ray powder on heating. It was confirmed by the Raman study not only in the disappearance of the vibrations assigned to the PO4, AsO4  but also in the appearance of the new vibrations attributed to the (PO3), which constitutes the P-O-P chain, giving a polymer with the formula: NaH2(P2O7)x(As2O7)(1-x).  The important variation was observed in all studies at 313 K, which could correspond to the transformation of the NDAP compounds of a solid crystal into a liquid form

    Aggregation dynamics and identification of aggregation-prone mutants of the von Hippel-Lindau tumor suppressor protein

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    International audienceQuality control mechanisms promote aggregation and degradation of misfolded proteins. In budding yeast, the human von Hippel-Lindau protein (pVHL, officially known as VHL) is misfolded and forms aggregates. Here, we investigated the aggregation of three pVHL isoforms (pVHL213, pVHL160, pVHL172) in fission yeast. The full-length pVHL213 isoform aggregates in highly dynamic small puncta and in large spherical inclusions, either close to the nucleus or to the cell ends. The large inclusions contain the yeast Hsp104 chaperone. Aggregate clearance is regulated by proteasomal degradation. The pVHL160 isoform forms dense foci and large irregularly shaped aggregates. In silico, prediction of pVHL aggregation propensity identified a key aggregation-promoting region within exon 2. Consistently, the pVHL172 isoform, which lacks exon 2, formed rare reduced inclusions. We studied the aggregation propensity of pVHL variants harbouring missense mutations found in kidney carcinomas. We show that the P86L mutation stimulated small aggregate formation, the P146A mutation increased large inclusion formation, whereas the I151S mutant destabilized pVHL. The prefoldin subunit Pac10 (the human homolog VBP-1 binds to pVHL) is required for pVHL stability. Reduction of soluble functional pVHL might be crucial in VHL-related diseases

    Iminophosphorane-based [P<sub>2</sub>N<sub>2</sub>] rhodium complexes: synthesis, reactivity, and application in catalysed transfer hydrogenation of polar bonds

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    International audience[Rh(P2N2)X] complexes (2-X, X = Cl, BF4) featuring a tetradentate iminophosphorane phosphine ligand were synthesised and characterised. X-Ray analysis provides evidence for a square planar geometry without coordination of the chloride anion. These complexes proved to be air-sensitive, and their oxidation to Rh(III) complexes 3-X was observed in air. The controlled reaction of 2-BF4 with one equivalent of hexachloroethane yielded [Rh(P2N2)Cl2(BF4)] (3-BF4). Direct synthesis of 3-Cl can also be achieved by coordination of the [P2N2] ligand to [RhCl(THT)3] (THT = tetrahydrothiophene). The reactivity of Rh(I) complexes 2 was further investigated, and no reaction was observed with silanes, aryl halides, or pinacolborane, although decomposition was observed under 1 atm of H2 upon prolonged heating. Interestingly, reduction of complex 3-Cl was observed by NMR upon treatment with silanes or sodium isopropoxide. Therefore, complex 3-Cl was used for catalytic transfer hydrogenation of polar bonds. The reduction of aromatic and aliphatic ketones can be carried out using 1% catalyst and 10% sodium isopropoxide, while imines are partially reduced under these conditions
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