Structure and phase stability of nanocrystalline Ce1−xLnxO2−x/2−δ (Ln = Yb, Lu) in oxidizing and reducing atmosphere

The structure and phase evolution of nanocrystalline Ce1−xLnxO2−x/2−δ (Ln = Yb, Lu, x = 0 − 1) oxides upon heating in H2 was studied for the first time. Up to 950 °C the samples were single-phase, with structure changing smoothly with x from fluorite type (F) to bixbyite type (C). For the Lu-doped samples heated at 1100 °C in the air and H2, phase separation into coexisting F- and C-type structures was observed for ~0.40 < x < ~0.70 and ~0.25 < x < ~0.70, respectively. It was found also that addition of Lu3+ and Yb3+ strongly hinders the crystallite growth of ceria during heat treatment at 800 and 950 °C in both atmospheres. Valency of Ce and Yb in Ce0.1Lu0.9O1.55−δ and Ce0.95Yb0.05O1.975−δ samples heated at 1100 °C was studied by XANES and magnetic measurements. In the former Ce was dominated by Ce4+, with small contribution of Ce3+ after heating in H2. In the latter, Yb existed exclusively as 3+ in both O2 and H2

Ubiquinone Analogs: A Mitochondrial Permeability Transition Pore-Dependent Pathway to Selective Cell Death

International audienceBACKGROUND: Prolonged opening of the mitochondrial permeability transition pore (PTP) leads to cell death. Various ubiquinone analogs have been shown to regulate PTP opening but the outcome of PTP regulation by ubiquinone analogs on cell fate has not been studied yet. METHODOLOGY/PRINCIPAL FINDINGS: The effects of ubiquinone 0 (Ub(0)), ubiquinone 5 (Ub(5)), ubiquinone 10 (Ub(10)) and decyl-ubiquinone (DUb) were studied in freshly isolated rat hepatocytes, cultured rat liver Clone-9 cells and cancerous rat liver MH1C1 cells. PTP regulation by ubiquinones differed significantly in permeabilized Clone-9 and MH1C1 cells from that previously reported in liver mitochondria. Ub(0) inhibited PTP opening in isolated hepatocytes and Clone-9 cells, whereas it induced PTP opening in MH1C1 cells. Ub(5) did not affect PTP opening in isolated hepatocytes and MH1C1 cells, but it induced PTP opening in Clone-9 cells. Ub(10) regulated PTP in isolated hepatocytes, whereas it did not affect PTP opening in Clone-9 and MH1C1 cells. Only DUb displayed the same effect on PTP regulation in the three hepatocyte lines tested. Despite such modifications in PTP regulation, competition between ubiquinones still occurred in Clone-9 and MH1C1 cells. As expected, Ub(5) induced a PTP-dependent cell death in Clone-9, while it did not affect MH1C1 cell viability. Ub(0) induced a PTP-dependent cell death in MH1C1 cells, but was also slightly cytotoxic in Clone-9 by an oxidative stress-dependent mechanism. CONCLUSIONS/SIGNIFICANCE: We found that various ubiquinone analogs regulate PTP in different ways depending on the cell studied. We took advantage of this unique property to develop a PTP opening-targeted strategy that leads to cell death specifically in cells where the ubiquinone analog used induces PTP opening, while sparing the cells in which it does not induce PTP opening

Screening of catalysts for the oxidative dehydrogenation of ethyl lactate to ethyl pyruvate, and optimization of the best catalysts

SSCI-VIDE+ECI2D+JMIInternational audienceEthyl lactat

Preparation of supported H3PW12040.6H2O for thiophenic compounds alkylation in FCC gasoline

International audienceIn FCC gasolines, thiophenic compounds alkylation with olefins of the feed followed by distillation of heavy sulfur compounds is a good alternative to classical hydrodesulfurization to eliminate sulfur. Among several acidic catalysts, silica-supported H3PW12O406H2O (HPW) has been found to be the best catalyst for the alkylation of 3-methylthiophene (3MT) with 2-methyl-2-butene (2M2B) taken as a model reaction in heterogeneous liquid phase systems at 358 K under nitrogen. The preparation of this catalyst has been optimized for this reaction and continuous catalytic tests have proved that this solid was very promising compared to traditional supported phosphoric acid or zeolites previously tested and used in industrial processes

Gas phase dehydration of 3-hydroxybutanone on orthophosphate catalysts for bio-based production of butenone for a sustainable industrial route to vitamin A

RMN+ECI2D+CLO:LCS:JMIInternational audienceAcetoi

Efficient catalysts for simultaneous dehydration of light alcohols in gas phase

SSCI-VIDE+ECI2D+JMIInternational audienc

Supported rhenium sulfide catalysts in thiophene and 4,6-dimethyldibenzothiophene hydrodesulfurization: Effect of acidity of the support over activities

1-2 Sepulveda, C. Belliere, V. Laurenti, D. Escalona, N. Garcia, R. Geantet, C. Vrinat, M.Three different zeolites, gamma-alumina and silica supports were used to prepare ReS2 catalysts by incipient wetness impregnation of ammonium perrhenate (NH4ReO4). The catalysts were characterized and tested in the hydrodesulfurization (HDS) of thiophene in an atmospheric fixed bed reactor, and of the 4,6-dimethyldibenzothiophene (4,6-DMDBT) HDS in a high pressure stirred tank reactor. The results showed that the acidity of the zeolites has a detrimental influence over hydrodesulfurization activity of the Re sulfide, contrarily to the enhancement observed previously with zeolite-supported Mo sulfide catalysts. The catalyst prepared over a non-acidic zeolite (HSZ-390) was found very efficient in thiophene HDS and comparable to silica for 4,6-DMDBT. (C) 2010 Elsevier B.V. All rights reserved

Chemical vapor deposition (DLI-CVD) and characterization of multiphasic molybdate-based catalysts for propene oxidation

fffInternational audienceliste mot clef

Influence of the nature of the rare earth element in rare earth orthophosphate used for light alcohol dehydration

SSCI-VIDE+ECI2D+JMIInternational audienc

Katryniok, B.

cited By 1International audienc