61 research outputs found

    Analysis of Sugar Component of a Hot Water Extract from Arabidopsis thaliana Pollen Tubes Using GC-EI-MS

    Get PDF
    International audienceExtraction with hot water is the oldest and simplest method used to recover pectin from an alcohol insoluble residue extract, although this method has not been widely used for the cell wall analysis of pollen tube, a model used to study cell wall. This protocol described this method applied for pectin extraction from 6 h-old Arabidopsis pollen tubes followed by a sugar composition analysis by gas chromatography mass spectrometry

    p-Type Ultrawide-Band-Gap Spinel ZnGa2O4: New Perspectives for Energy Electronics

    Get PDF
    The family of spinel compounds is a large and important class of multifunctional materials of general formulation AB2X4 with many advanced applications in energy and optoelectronic areas such as fuel cells, batteries, catalysis, photonics, spintronics, and thermoelectricity. In this work, it is demonstrated that the ternary ultrawide-band-gap (∼5 eV) spinel zinc gallate (ZnGa2O4) arguably is the native p-type ternary oxide semiconductor with the largest Eg value (in comparison with the recently discovered binary p-type monoclinic β-Ga2O3 oxide). For nominally undoped ZnGa2O4 the high-temperature Hall effect hole concentration was determined to be as large as p = 2 × 1015 cm–3, while hole mobilities were found to be μh = 7–10 cm2/(V s) (in the 680–850 K temperature range). An acceptor-like small Fermi level was further corroborated by X-ray spectroscopy and by density functional theory calculations. Our findings, as an important step toward p-type doping, opens up further perspectives for ultrawide-band-gap bipolar spinel electronics and further promotes ultrawide-band-gap ternary oxides such as ZnGa2O4 to the forefront of the quest of the next generation of semiconductor materials for more efficient energy optoelectronics and power electronics

    Native defect association in beta-Ga2O3 enables room-temperature p-type conductivity

    Full text link
    The room temperature hole conductivity of the ultra wide bandgap semiconductor beta Ga2O3 is a pre-requisite for developing the next-generation electronic and optoelectronic devices based on this oxide. In this work, high-quality p-type beta-Ga2O3 thin films grown on r-plane sapphire substrate by metalorganic chemical vapor deposition (MOCVD) exhibit Rho = 50000Ohm.cm resistivity at room temperature. A low activation energy of conductivity as Ea2=170 meV was determined, associated to the oxygen - gallium native acceptor defect complex. Further, taking advantage of cation (Zn) doping, the conductivity of Ga2O3:Zn film was remarkably increased by three orders of magnitude, showing a long-time stable room-temperature hole conductivity with the conductivity activation energy of around 86 meV.Comment: 21pages; 9figure

    Interleukin-18 produced by bone marrow- derived stromal cells supports T-cell acute leukaemia progression

    Get PDF
    International audienceDevelopment of novel therapies is critical for T-cell acute leukae-mia (T-ALL). Here, we investigated the effect of inhibiting the MAPK/MEK/ERK pathway on T-ALL cell growth. Unexpectedly, MEK inhibitors (MEKi) enhanced growth of 70% of human T-ALL cell samples cultured on stromal cells independently of NOTCH activa-tion and maintained their ability to propagate in vivo. Similar results were obtained when T-ALL cells were cultured with ERK1/ 2-knockdown stromal cells or with conditioned medium from MEKi-treated stromal cells. Microarray analysis identified interleu-kin 18 (IL-18) as transcriptionally up-regulated in MEKi-treated MS5 cells. Recombinant IL-18 promoted T-ALL growth in vitro, whereas the loss of function of IL-18 receptor in T-ALL blast cells decreased blast proliferation in vitro and in NSG mice. The NFKB pathway that is downstream to IL-18R was activated by IL-18 in blast cells. IL-18 circulating levels were increased in T-ALL-xeno-grafted mice and also in T-ALL patients in comparison with controls. This study uncovers a novel role of the pro-inflammatory cytokine IL-18 and outlines the microenvironment involvement in human T-ALL development

    A new reciprocal translocation in a subfertile bull

    Get PDF
    Three bulls of the Montbéliarde breed that exhibited fertility rates lower than 30% following more than 400 artificial inseminations were examined. Semen quality (sperm motility and morphology) from these bulls was normal. Fertilizing ability estimated from in vitro embryo production results was studied for two of them. In vitro production rate was very low for one bull (A) and normal for the other (B). Cytogenetic analyses were carried out on the three bulls using chromosome banding techniques. These analyses revealed a reciprocal translocation (12;17)(q22;q14) in bull B. Based on family analyses, the hypothesis of a de novo origin of this rearrangement is proposed

    Viral to metazoan marine plankton nucleotide sequences from the Tara Oceans expedition

    Get PDF
    A unique collection of oceanic samples was gathered by the Tara Oceans expeditions (2009-2013), targeting plankton organisms ranging from viruses to metazoans, and providing rich environmental context measurements. Thanks to recent advances in the field of genomics, extensive sequencing has been performed for a deep genomic analysis of this huge collection of samples. A strategy based on different approaches, such as metabarcoding, metagenomics, single-cell genomics and metatranscriptomics, has been chosen for analysis of size-fractionated plankton communities. Here, we provide detailed procedures applied for genomic data generation, from nucleic acids extraction to sequence production, and we describe registries of genomics datasets available at the European Nucleotide Archive (ENA, www.ebi.ac.uk/ena). The association of these metadata to the experimental procedures applied for their generation will help the scientific community to access these data and facilitate their analysis. This paper complements other efforts to provide a full description of experiments and open science resources generated from the Tara Oceans project, further extending their value for the study of the world's planktonic ecosystems

    Assessment of Large Critical Electric Field in Ultra-wide Bandgap p- type Spinel ZnGa2O4

    Get PDF
    International audienceThe spinel Zinc Gallate ZnGa2O4 stands out among the emerging ultra-wide bandgap (~5eV) semiconductors as the ternary complex oxide with the widest gap where bipolar conductivity (electrons and holes) has been demonstrated. For power and energy electronic applications, a fundamental property of the material is its critical electric field (Ec), as, for example, the Baliga’s figure of merit scales as ~Ec3 . However, the critical electric field of ZnGa2O4 is yet unknown. In this work, it is carried out with the thermodynamic analysis of point defects and free carriers versus oxygen pressure. According to this analysis, highly resistive p- -type ZnGa2O4 thin films on sapphire and Si substrates were elaborated by metal organic chemical vapor deposition (MOCVD) technique. Hall Effect measurements confirmed a low carrier level at room temperature (estimated at 10 11 cm -3 ), and breakdown voltage characterizations on a polycrystalline thin film on p- -type doped silicon substrates have been performed. We can deduce a value of the critical electric field to be at least 5.3 MV/cm for p- -type ZnGa2O4
    corecore