201 research outputs found
Gaseous Hydrocarbon Separations Using Functionalized Ionic Liquids
International audienceThe functionalization of the side chains on the cation or the anion of an ionic liquid is a common approach to tailor its properties for different processes including the separation of gases. In this paper, we present the current state of the art concerning the usage of ionic liquids for hydrocarbon separations. We also show how the functionalization of ionic liquids or the appropriate anion/cation combinations can contribute to the increase of the performance of the ionic liquids for the separation of gaseous hydrocarbons â either by improving the capacity of the ionic liquid to absorb a given gas or by increasing the selectivity towards a particular hydrocarbon. Original results concerning the usage of olefin-complexing metal salts of lithium (I), nickel (II) and copper (II) dissolved in ionic liquids for selectively absorbing light olefins are presented. It is observed that the absorption capacity of an imidazolium-based ionic liquid is doubled by the addition of a copper (II) salt. This result is compared with the effect of the functionalization of the ionic liquid and the advantages and difficulties of the two approaches are analyzed.La fonctionnalisation des chaĂźnes latĂ©rales sur le cation ou lâanion dâun liquide ionique est une approche commune pour adapter ses propriĂ©tĂ©s pour les diffĂ©rents processus, y compris la sĂ©paration de gaz. Dans cet article, nous prĂ©sentons lâĂ©tat actuel des recherches concernant lâutilisation de liquides ioniques pour les sĂ©parations dâhydrocarbures gazeux. Nous montrons comment la fonctionnalisation de liquides ioniques ou des combinaisons dâanions/cations appropriĂ©es peuvent contribuer Ă lâaugmentation de leur performance pour la sĂ©paration des hydrocarbures gazeux â soit par lâamĂ©lioration de la capacitĂ© du liquide ionique pour absorber un gaz donnĂ© ou en augmentant la sĂ©lectivitĂ© pour un hydrocarbure particulier. Des rĂ©sultats originaux concernant lâutilisation de sels mĂ©talliques de lithium (I), le nickel (II) et le cuivre (II) dissous dans des liquides ioniques pour absorber sĂ©lectivement des olĂ©fines lĂ©gĂšres sont prĂ©sentĂ©s. On constate que la capacitĂ© dâabsorption dâun liquide ionique Ă base dâimidazolium est doublĂ©e par addition dâun sel de cuivre (II). Ce rĂ©sultat est comparĂ© avec lâeffet de la fonctionnalisation du liquide ionique. Les avantages et les difficultĂ©s de ces deux approches sont analysĂ©s
Spectral deconvolution in electrophoretic NMR to investigate the migration of neutral molecules in electrolytes
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Targeting adequate thermal stability and fire safety in selecting ionic liquid-based electrolytes for energy storage
CAPLUS AN 2014:16740(Journal; Online Computer File)International audienceThe energy storage market relating to lithium based systems regularly grows in size and expands in terms of a portfolio of energy and power demanding applications. Thus safety focused research must more than ever accompany related technological breakthroughs regarding performance of cells, resulting in intensive research on the chemistry and materials science to design more reliable batteries. Formulating electrolyte solutions with nonvolatile and hardly flammable ionic liquids instead of actual carbonate mixtures could be safer. However, few definitions of thermal stability of electrolytes based on ionic liquids have been reported in the case of abuse conditions (fire, shortcut, overcharge or overdischarge). This work investigates thermal stability up to combustion of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C1C4Im][NTf2]) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([PYR14][NTf2]) ionic liquids, and their corresponding electrolytes containing lithium bis(trifluoromethanesulfonyl)imide LiNTf2. Their possible routes of degradation during thermal abuse testings were investigated by thermodynamic studies under several experimental conditions. Their behaviours under fire were also tested, including the analysis of emitted compounds
Sea level and turbidity controls on mangrove soil surface elevation change
Increases in sea level are a threat to seaward fringing mangrove forests if levels of inundation exceed the physiological tolerance of the trees; however, tidal wetlands can keep pace with sea level rise if soil surface elevations can increase at the same pace as sea level rise. Sediment accretion on the soil surface and belowground production of roots are proposed to increase with increasing sea level, enabling intertidal habitats to maintain their position relative to mean sea level, but there are few tests of these predictions in mangrove forests. Here we used variation in sea level and the availability of sediments caused by seasonal and inter-annual variation in the intensity of La Nina-El Nino to assess the effects of increasing sea level on surface elevation gains and contributing processes (accretion on the surface, subsidence and root growth) in mangrove forests. We found that soil surface elevation increased with mean sea level (which varied over 250 mm during the study) and with turbidity at sites where fine sediment in the water column is abundant. In contrast, where sediments were sandy, rates of surface elevation gain were high, but not significantly related to variation in turbidity, and were likely to be influenced by other factors that deliver sand to the mangrove forest. Root growth was not linked to soil surface elevation gains, although it was associated with reduced shallow subsidence, and therefore may contribute to the capacity of mangroves to keep pace with sea level rise. Our results indicate both surface (sedimentation) and subsurface (root growth) processes can influence mangrove capacity to keep pace with sea level rise within the same geographic location, and that current models of tidal marsh responses to sea level rise capture the major feature of the response of mangroves where fine, but not coarse, sediments are abundant
Surface organometallic chemistry: a route to well-defined boron heterogeneous co-catalyst for olefin polymerisation
Corrigendum to âCharacterization of a novel aphid prenyltransferase displaying dual geranyl/farnesyl diphosphate synthase activityâ [FEBS Lett. 582 (2008) 1928â1934]
Gene expression signature discriminates sporadic from post-radiotherapy-induced thyroid tumors
Both external and internal exposure to ionizing radiation are strong risk factors for the development of thyroid tumors. Until now, the diagnosis of radiation-induced thyroid tumors has been deduced from a network of arguments taken together with the individual history of radiation exposure. Neither the histological features nor the genetic alterations observed in these tumors have been shown to be specific fingerprints of an exposure to radiation. The aim of our work is to define ionizing radiation-related molecular specificities in a series of secondary thyroid tumors developed in the radiation field of patients treated by radiotherapy. To identify molecular markers that could represent a radiation-induction signature, we compared 25K microarray transcriptome profiles of a learning set of 28 thyroid tumors, which comprised 14 follicular thyroid adenomas (FTA) and 14 papillary thyroid carcinomas (PTC), either sporadic or consecutive to external radiotherapy in childhood. We identified a signature composed of 322 genes which discriminates radiation-induced tumors (FTA and PTC) from their sporadic counterparts. The robustness of this signature was further confirmed by blind case-by-case classification of an independent set of 29 tumors (16 FTA and 13 PTC). After the histology code break by the clinicians, 26/29 tumors were well classified regarding tumor etiology, 1 was undetermined, and 2 were misclassified. Our results help shed light on radiation-induced thyroid carcinogenesis, since specific molecular pathways are deregulated in radiation-induced tumors
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Clades of huge phages from across Earth's ecosystems.
Bacteriophages typically have small genomes1 and depend on their bacterial hosts for replication2. Here we sequenced DNA from diverse ecosystems and found hundreds of phage genomes with lengths of more than 200 kilobases (kb), including a genome of 735 kb, which is-to our knowledge-the largest phage genome to be described to date. Thirty-five genomes were manually curated to completion (circular and no gaps). Expanded genetic repertoires include diverse and previously undescribed CRISPR-Cas systems, transfer RNAs (tRNAs), tRNA synthetases, tRNA-modification enzymes, translation-initiation and elongation factors, and ribosomal proteins. The CRISPR-Cas systems of phages have the capacity to silence host transcription factors and translational genes, potentially as part of a larger interaction network that intercepts translation to redirect biosynthesis to phage-encoded functions. In addition, some phages may repurpose bacterial CRISPR-Cas systems to eliminate competing phages. We phylogenetically define the major clades of huge phages from human and other animal microbiomes, as well as from oceans, lakes, sediments, soils and the built environment. We conclude that the large gene inventories of huge phages reflect a conserved biological strategy, and that the phages are distributed across a broad bacterial host range and across Earth's ecosystems
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