996 resultados para LI-1-XHXIO3


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The elemental distribution of as-received (non-charged) and charged Li-ion battery positive electrodes containing LixNi0.8Co0.15Al0.05O2 (0.75 ? x ? 1.0) microparticles as active material is characterized by combining μ-PIXE and μ-PIGE techniques. PIGE measurements evidence that the Li distribution is inhomogeneous (existence of Li-rich and Li-depleted regions) in as-received electrodes corresponding with the distribution of secondary particles but it is homogeneous within the studied individual secondary micro-particles. The dependence of the Li distribution on electrode thickness and on charging conditions is characterized by measuring the Li distribution maps in specifically fabricated cross-sectional samples. These data show that decreasing the electrode thickness down to 35 μm and charging the batteries at slow rate give rise to more homogeneous Li depth profiles.

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Desarrollar cerámicas de Li con propiedades adecuadas para ser utilizadas en el manto reproductor de reactores de fusión. Estudiar el comportamiento de especies ligeras, en particular D, en cerámicas de Li en función de: Composición, Microestructura, Temperatura.

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En claro alineamiento con estrategias de sostenibilidad en el uso de recursos naturales en un escenario constante de aumento de la demanda energética mundial, el desarrollo de la tecnología energética en la Historia de la Especie Humana muestra un vector de evolución permanente desde su origen en el sentido del desarrollo y uso de nuevas fuentes energéticas con la explotación de recursos naturales de manera más eficiente: soluciones energéticas con aumento de la densidad energética (exoenergía de proceso por unidad de masa de recurso natural). Así el cambio de escala en la demanda de explotación del Litio como recurso natural se viene presentando en la última década ligada al desarrollo del mercado de las baterías "ion-Litio" y los requisitos de combustible (Deuterio y Litio) en el camino de la fusión nuclear como opción energética próxima. El análisis anticipado de las demandas sinérgicas a escala de ambos mercados aparece de enorme interés prospectivo en sus aspectos técnicos: (1) tecnologías de base para la extracción mineral y de agua marina y (2) su enriquecimiento isotópico (de interés sinérgico; 7Li para baterías eficientes ion-litio; 6Li como regenerador de tritio en ciclo de combustible en fusión nuclear) a la vez que en sus aspectos económicos. Este Proyecto realiza: (1) un ejercicio de análisis prospectivo de la demanda y de mercado para el enriquecimiento 6Li/7Li para las próximas décadas, (2) se califican los desarrollos tecnológicos específicos que van a poder permitir la producción a escala conforme a la demanda; (3) se selecciona y califica una técnica [de centrifugación / termo-difusión/ destilación combinada] como opción tecnológicamente viable para la producción a escala de formas litiadas; (4) se propone un diseño conceptual de planta de producción y finalmente (5) propone un estudio de viabilidad para la demostración de proceso y construcción de dicha planta de demostración de la nueva capacidad tecnológica. ABSTRACT Clearly aligned with sustainability strategies under growing world energy demand in the use of natural resources the development of energy technology in the history of the human species shows a vector of ongoing evolution from its origin in the sense of the development and use of new energy sources with the exploitation of natural resources in a more efficient manner. The change of scale in the demand for exploitation of Lithium as a natural resource appears during the last decade as bound to the deployment of "lithium-ion" batteries market and to the Nuclear Fusion fuels (deuterium and lithium) supply scaled demands. The prospective analysis of demands to scale in both markets appears in scene with huge prospective interest in its technical aspects: (1) base technologies for mineral and water marine extraction (2) its isotopic enrichment (synergistic interests; 7Li efficient battery Li-ion; 6Li as fusion nuclear fuel breeder (tritium) as well as in its economic aspects. This Project: (1) propose a prospective analysis exercise of the synergistic supply demand for coming decades for the enrichment of 6Li and 7Li, (2) qualifies specific technological developments ongoing to respond to supply demand; (3) select and qualifies an appropriate technique [combined centrifugation/thermo-diffusion/distillation] as technologically viable option for lithiated forms scaled-production; (4) proposes a conceptual design of production plant based on the technique and finally (5) proposes a feasibility study for the process demonstration and construction of this new technological capability Demonstration Plant.

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In future power plants (i.e. DEMO), the nuclear fusion of hydrogen isotopes will be used for energy production. The behaviour of hydrogen isotopes in lithium-enriched ceramics for breeder blankets (BBs) is one of the most important items to be understood. In this paper we present the chemical, microstructural and morphological features of Li4SiO4, Li2TiO3 and a third ceramic candidate with a higher Li:Si proportion (3:1), implanted with D at an energy of 100 keV and at room temperature at a fluence of 1 × 1017 cm−2. The D depth-profile in as-implanted and annealed ceramics (at T ⩽ 200 °C) was characterised by Resonance Nuclear Reaction Analysis (RNRA). The RNRA data indicate that the total amount of D is retained at room temperature, while annealing at 100 °C promotes D release and annealing at T ⩾ 150 °C drives D to completely desorb from all the studied ceramics. D release will be discussed as a function of the microstructurural and morphological features of each material.

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El objetivo del estudio fue comparar el peso corporal adulto de gallinas ponedoras alojadas en jaulas enriquecidas y sometidas a diferentes intensidades de iluminación de acuerdo con el esquema factorial 2x3: iluminación del pasillo (lateral y central) versus iluminación del piso (bajo, intermedio y alto) , evaluado en el periodo de 18 hasta 60 se manas de edad de acuerdo con el modelo no lineal de Gompertz. Las gallinas fueron alojadas en dos baterías de 3 pisos, con dos filas por piso y cinco jaulas por fila (25 aves/jaula), con un total de 1.500 gallinas. Dichas jaulas cumplen la Directiva CE 199 9/74. Se pesaron 10 gallinas de cada jaula, identificadas con anillas de color diferente, a la edad de 18, 20, 24, 28, 32, 36, 44, 52 y 60 semanas. Para el ajuste de los parámetros B y C del modelo de Gompertz se utilizó el peso medio de las pollitas hasta la 17 a semana edad, pues tuvimos como objetivo mantener dichos parámetros B y C de la curva de Gompertz para todos los tratamientos, ya que el fin del estudio fue evaluar la influencia de la intensidad luminosa en el peso adulto de las gallinas, es decir, el crecimiento después del punto de inflexión de la curva.

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Vaccination of mice with activated autoantigen-reactive CD4+ T cells (T cell vaccination, TCV) has been shown to induce protection from the subsequent induction of a variety of experimental autoimmune diseases, including experimental allergic encephalomyelitis (EAE). Although the mechanisms involved in TCV-mediated protection are not completely known, there is some evidence that TCV induces CD8+ regulatory T cells that are specific for pathogenic CD4+ T cells. Previously, we demonstrated that, after superantigen administration in vivo, CD8+ T cells emerge that preferentially lyse and regulate activated autologous CD4+ T cells in a T cell receptor (TCR) Vβ-specific manner. This TCR Vβ-specific regulation is not observed in β2-microglobulin-deficient mice and is inhibited, in vitro, by antibody to Qa-1. We now show that similar Vβ8-specific Qa-1-restricted CD8+ T cells are also induced by TCV with activated CD4+ Vβ8+ T cells. These CD8+ T cells specifically lyse murine or human transfectants coexpressing Qa-1 and murine TCR Vβ8. Further, CD8+ T cell hybridoma clones generated from B10.PL mice vaccinated with a myelin basic protein-specific CD4+Vβ8+ T cell clone specifically recognize other CD4+ T cells and T cell tumors that express Vβ8 and the syngeneic Qa-1a but not the allogeneic Qa-1b molecule. Thus, Vβ-specific Qa-1-restricted CD8+ T cells are induced by activated CD4+ T cells. We suggest that these CD8+ T cells may function to specifically regulate activated CD4+ T cells during immune responses.

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Steroids, thyroid hormones, vitamin D3, and retinoids are lipophilic small molecules that regulate diverse biological effects such as cell differentiation, development, and homeostasis. The actions of these hormones are mediated by steroid/nuclear receptors which function as ligand-dependent transcriptional regulators. Transcriptional activation by ligand-bound receptors is a complex process requiring dissociation and recruitment of several additional cofactors. We report here the cloning and characterization of receptor-associated coactivator 3 (RAC3), a human transcriptional coactivator for steroid/nuclear receptors. RAC3 interacts with several liganded receptors through a mechanism which requires their respective ligand-dependent activation domains. RAC3 can activate transcription when tethered to a heterologous DNA-binding domain. Overexpression of RAC3 enhances the ligand-dependent transcriptional activation by the receptors in mammalian cells. Sequence analysis reveals that RAC3 is related to steroid receptor coactivator 1 (SRC-1) and transcriptional intermediate factor 2 (TIF2), two of the most potent coactivators for steroid/nuclear receptors. Thus, RAC3 is a member of a growing coactivator network that should be useful as a tool for understanding hormone action and as a target for developing new therapeutic agents that can block hormone-dependent neoplasia.

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Two isoforms of the substance P (SP) receptor, differing in the length of the cytoplasmic carboxyl-terminus by ≈8 kDa, have been detected previously in rat salivary glands and other tissues. The binding and functional properties of these two isoforms have been investigated using full-length (407 amino acids) and carboxyl-terminally truncated (324 amino acids) rat SP receptors transfected stably into Chinese hamster ovary cells. Both the full-length and the truncated receptor bound radiolabeled SP with a similar Kd (≈0.1 nM). The average number of high affinity SP binding sites per cell was 1.0 × 105 and 0.3 × 105 for the full-length and the truncated SP receptor, respectively. In both cell lines, SP induced a rapid but transient increase in cytosolic calcium concentration ([Ca2+]i), which consisted of the release of Ca2+ from intracellular stores and the influx of extracellular Ca2+. Both components are dependent on phospholipase C activation. Although the full-length and the truncated receptor utilize the same calcium pathways, they differ in their EC50 values (0.28 nM for the full-length; 0.07 nM for the truncated). These differences in responsiveness may be related to the observed differences in receptor desensitization. The truncated receptor, in contrast to the full-length receptor, does not undergo rapid and long-lasting desensitization. Cells possessing the short isoform of the SP receptor would thus be expected to exhibit a prolonged responsiveness.

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Mutant presenilins have been found to cause Alzheimer disease. Here, we describe the identification and characterization of HOP-1, a Caenorhabditis elegans presenilin that displays much more lower sequence identity with human presenilins than does the other C. elegans presenilin, SEL-12. Despite considerable divergence, HOP-1 appears to be a bona fide presenilin, because HOP-1 can rescue the egg-laying defect caused by mutations in sel-12 when hop-1 is expressed under the control of sel-12 regulatory sequences. HOP-1 also has the essential topological characteristics of the other presenilins. Reducing hop-1 activity in a sel-12 mutant background causes synthetic lethality and terminal phenotypes associated with reducing the function of the C. elegans lin-12 and glp-1 genes. These observations suggest that hop-1 is functionally redundant with sel-12 and underscore the intimate connection between presenilin activity and LIN-12/Notch activity inferred from genetic studies in C. elegans and mammals.

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Multiprotein bridging factor 1 (MBF1) is a transcriptional cofactor that bridges between the TATA box-binding protein (TBP) and the Drosophila melanogaster nuclear hormone receptor FTZ-F1 or its silkworm counterpart BmFTZ-F1. A cDNA clone encoding MBF1 was isolated from the silkworm Bombyx mori whose sequence predicts a basic protein consisting of 146 amino acids. Bacterially expressed recombinant MBF1 is functional in interactions with TBP and a positive cofactor MBF2. The recombinant MBF1 also makes a direct contact with FTZ-F1 through the C-terminal region of the FTZ-F1 DNA-binding domain and stimulates the FTZ-F1 binding to its recognition site. The central region of MBF1 (residues 35–113) is essential for the binding of FTZ-F1, MBF2, and TBP. When the recombinant MBF1 was added to a HeLa cell nuclear extract in the presence of MBF2 and FTZ622 bearing the FTZ-F1 DNA-binding domain, it supported selective transcriptional activation of the fushi tarazu gene as natural MBF1 did. Mutations disrupting the binding of FTZ622 to DNA or MBF1, or a MBF2 mutation disrupting the binding to MBF1, all abolished the selective activation of transcription. These results suggest that tethering of the positive cofactor MBF2 to a FTZ-F1-binding site through FTZ-F1 and MBF1 is essential for the binding site-dependent activation of transcription. A homology search in the databases revealed that the deduced amino acid sequence of MBF1 is conserved across species from yeast to human.

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The proinflammatory cytokine interleukin 1 (IL-1) activates the transcription of many genes encoding acute phase and proinflammatory proteins, a function mediated primarily by the transcription factor NF-κB. An early IL-1 signaling event is the recruitment of the Ser/Thr kinase IRAK to the type I IL-1 receptor (IL-1RI). Here we describe the function of a previously identified IL-1 receptor subunit designated IL-1 receptor accessory protein (IL-1RAcP). IL-1 treatment of cells induces the formation of a complex containing both IL-1RI and IL-1RAcP. IRAK is recruited to this complex through its association with IL-1RAcP. Overexpression of an IL-1RAcP mutant lacking its intracellular domain, the IRAK-binding domain, prevented the recruitment of IRAK to the receptor complex and blocked IL-1-induced NF-κB activation.

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The transcription factors nuclear factor of activated T cells (NFAT) and activator protein 1 (AP-1) coordinately regulate cytokine gene expression in activated T-cells by binding to closely juxtaposed sites in cytokine promoters. The structural basis for cooperative binding of NFAT and AP-1 to these sites, and indeed for the cooperative binding of transcription factors to composite regulatory elements in general, is not well understood. Mutagenesis studies have identified a segment of AP-1, which lies at the junction of its DNA-binding and dimerization domains (basic region and leucine zipper, respectively), as being essential for protein–protein interactions with NFAT in the ternary NFAT/AP-1/DNA complex. In a model of the ternary complex, the segment of NFAT nearest AP-1 is the Rel insert region (RIR), a feature that is notable for its hypervariability in size and in sequence amongst members of the Rel transcription factor family. Here we have used mutational analysis to study the role of the NFAT RIR in binding to DNA and AP-1. Parallel yeast one-hybrid screening assays in combination with alanine-scanning mutagenesis led to the identification of four amino acid residues in the RIR of NFAT2 (also known as NFATC1 or NFATc) that are essential for cooperativity with AP-1 (Ile-544, Glu-545, Thr-551, and Ile-553), and three residues that are involved in interactions with DNA (Lys-538, Arg-540, and Asn-541). These results were confirmed and extended through in vitro binding assays. We thus conclude that the NFAT RIR plays an essential dual role in DNA recognition and cooperative binding to AP-1 family transcription factors.

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Growth factors such as insulin regulate phosphatidylinositol 3-kinase-dependent actin cytoskeleton rearrangement in many types of cells. However, the mechanism by which the insulin signal is transmitted to the actin cytoskeleton remains largely unknown. Yeast two-hybrid screening revealed that the phosphatidylinositol 3-kinase downstream effector phosphoinositide-dependent protein kinase-1 (PDK1) interacted with protein kinase N (PKN), a Rho-binding Ser/Thr protein kinase potentially implicated in a variety of cellular events, including phosphorylation of cytoskeletal components. PDK1 and PKN interacted in vitro and in intact cells, and this interaction was mediated by the kinase domain of PDK1 and the carboxyl terminus of PKN. In addition to a direct interaction, PDK1 also phosphorylated Thr774 in the activation loop and activated PKN. Insulin treatment or ectopic expression of the wild-type PDK1 or PKN, but not protein kinase Cζ, induced actin cytoskeleton reorganization and membrane ruffling in 3T3-L1 fibroblasts and Rat1 cells that stably express the insulin receptor (Rat1-IR). However, the insulin-stimulated actin cytoskeleton reorganization in Rat1-IR cells was prevented by expression of kinase-defective PDK1 or PDK1-phosphorylation site-mutated PKN. Thus, phosphorylation by PDK1 appears to be necessary for PKN to transduce signals from the insulin receptor to the actin cytoskeleton.