Thermoluminescence of a mixed rare earth phosphate powder La1−x−yCexTbyPO4

International audienceThe properties of thermoluminescence (TL) observed from various mixed rare earth (RE) phosphate powders La1−x−yCexTbyPO4 are reported. TL peaks appear around −175°C, −135°C, −80°C, −35°C and +25°C and the TL emission spectra of La1−x−yCexTbyPO4 are mainly composed of characteristic line transitions of Tb3+ ions. The results show that the co-doping with Ce3+ is not required to observe the TL emission of Tb3+. A model for the recombination mechanisms of the various TL peaks is discussed

Effect of different fluxes on the morphology of the LaPO4 : Ce, Tb phosphor

LaPO4:Ce, Tb (LaCeT) is a green phosphor used in fluorescent lamps and plasma display panels. In order to improve the fabrication process of this phosphor, different fluxes have been used. Their influence on the particles size and shape is described thanks to SEM analyses. Fluxes were found to control the morphology of particles : LaCeT particles, from spherical to parallelepiped-like shape, with suitable sizes, from 0.1 to 10 µm, have been synthesized. Furthermore the photoluminescence emission of the obtained powders has been checked, and it has been proved that the effect of the fluxes studied is not harmful to the LaCeT final optical properties

Contrôle de la morphologie des poudres par l'ajout de fondants : Application à un luminophore

National audienceCe travail porte sur l'amélioration du procédé de fabrication des luminophores et en particulier un phosphate de lanthane : LaPO4:Ce,Tb (LaCeT). L'influence de fondants carbonatés (Li2CO3, Na2CO3, K2CO3, ...) sur la taille et la forme des grains du luminophore y est décrite. Pour ce faire des analyses par microscopie électronique à balayage ont été effectuées. Des résultats concluants ont pu en être tirés : des grains de morphologie contrôlée (forme de sphères ou de plaquettes) et de taille adaptée (modulable de 0,1 à 10 μm) ont pu être synthétisés. Par ailleurs, la photoluminescence des poudres obtenues a été contrôlée et il a été montré que l'effet du fondant n'est pas dommageable aux propriétés optiques des luminophores finales

Irradiation damages in Ti3SiC2: formation and characterisation of the oxide layer

International audienceThe concept of the fuel for the IVth generation reactors should consist of fuel pellets surrounded with a matrix that must contain fission products. Thanks to their interesting thermo-mechanical properties, carbides are sensed to become this matrix. Among the studied carbides, Ti3SiC2 can be distinguished; actually, its nano-laminated structure confers to it some softness as well as a better toughness than classical carbides like SiC or TiC. However, before to use this remarkable carbide, a study of its behaviour under irradiation must be led. Thus, some characterisations were performed on 75 MeV Kr irradiated specimens. They allowed to underline that TiO2 (formed on the surface of Ti3SiC2 during the surface preparation) seems to be sputtered by irradiation, and that the unit cell of Ti3SiC2 is dilated along c axis

Dommages d'irradiation dans Ti3SiC2

Les carbures, de par leurs propriétés remarquables, sont pressentis comme matériau de structure autour du combustible du réacteur de génération IV. Parmi ceux étudiés, Ti3SiC2 se distingue car il associe les propriétés des céramiques à celles des métaux. Cependant, son comportement sous irradiation n'est pas connu. Des caractérisations ont été réalisées sur des échantillons irradiés aux ions Kr à 75 MeV. Elles ont permis de mettre en exergue que TiO2 (formé en surface de Ti3SiC2) est pulvérisé par l'irradiation et que la maille cristalline de Ti3SiC2 se dilate suivant c

Nouveaux milieux, nouveaux gibiers, nouveaux chasseurs ? Évolution des pratiques cynégétiques dans les Pyrénées du Tardiglaciaire au début du Postglaciaire

National audienceLes changements climatiques survenus durant le Tardiglaciaire et au début du Postglaciaire ont modifié de manière considérable l'environnement naturel des populations préhistoriques. Pour certains auteurs, ces modifications seraient à l'origine d'une intégration massive des petits animaux dans l'alimentation. Dans les Pyrénées françaises et sur leurs marges, une intensification de la capture des petits gibiers apparaît à la fin du Dryas ancien. Les données archéozoologiques couplées aux données paléoenvironnementales montrent que le réchauffement et les modifications environnementales qui en découlent ne sont pas directement responsables des changements observés dans l'exploitation du milieu animal. En raison de la multiplicité des facteurs déclenchants et de leur interaction probable, il est cependant difficile, dans l'état actuel des recherches, d'appréhender les causes qui ont conduit les populations du Tardiglaciaire à intégrer les petits gibiers dans leur économie et leur univers symbolique

Screening of MAMLD1 Mutations in 70 Children with 46,XY DSD: Identification and Functional Analysis of Two New Mutations

More than 50% of children with severe 46,XY disorders of sex development (DSD) do not have a definitive etiological diagnosis. Besides gonadal dysgenesis, defects in androgen biosynthesis, and abnormalities in androgen sensitivity, the Mastermind-like domain containing 1 (MAMLD1) gene, which was identified as critical for the development of male genitalia, may be implicated. The present study investigated whether MAMLD1 is implicated in cases of severe 46,XY DSD and whether routine sequencing of MAMLD1 should be performed in these patients

The Phosphate Fast-Responsive Genes <i>PECP1</i> and <i>PPsPase1</i> Affect Phosphocholine and Phosphoethanolamine Content

International audiencePhosphate starvation-mediated induction of the HAD-type phosphatases PPsPase1 (AT1G73010) and PECP1 (AT1G17710) has been reported in Arabidopsis (Arabidopsis thaliana). However, little is known about their in vivo function or impact on plant responses to nutrient deficiency. The preferences of PPsPase1 and PECP1 for different substrates have been studied in vitro but require confirmation in planta. Here, we examined the in vivo function of both enzymes using a reverse genetics approach. We demonstrated that PPsPase1 and PECP1 affect plant phosphocholine and phosphoethanolamine content, but not the pyrophosphate-related phenotypes. These observations suggest that the enzymes play a similar role in planta related to the recycling of polar heads from membrane lipids that is triggered during phosphate starvation. Altering the expression of the genes encoding these enzymes had no effect on lipid composition, possibly due to compensation by other lipid recycling pathways triggered during phosphate starvation. Furthermore, our results indicated that PPsPase1 and PECP1 do not influence phosphate homeostasis, since the inactivation of these genes had no effect on phosphate content or on the induction of molecular markers related to phosphate starvation. A combination of transcriptomics and imaging analyses revealed that PPsPase1 and PECP1 display a highly dynamic expression pattern that closely mirrors the phosphate status. This temporal dynamism, combined with the wide range of induction levels, broad expression, and lack of a direct effect on Pi content and regulation, makes PPsPase1 and PECP1 useful molecular markers of the phosphate starvation response

Sistematización del proceso participativo para la creación de la política de innovación en la UNED

Las universidades, como organizaciones sociales requieren transitar en un proceso de transformación que les permita repensar su quehacer y, alcanzar una mayor cercanía a las comunidades educativas, por medio del trabajo en sus áreas sustantivas. La innovación, se constituye en este contexto, en un acicate para la educación superior; que invoca cambio y transformación profunda en lo que hace y en las formas, procesos y herramientas que emplea para lograrlo. Esta concepción de innovación va más allá de lo que se considera en estos días y en diferentes contextos, reducida al uso intensivo de las tecnologías de la información y comunicación. La necesidad de sistematizar y generar conocimiento que permitiera comprender y fortalecer las capacidades innovadoras en la UNED, propició que un grupo interdisciplinario, conformado por decisión abierta e individual de sus integrantes y, con representación de las distintas Vicerrectorías de la universidad, se organizara y conformara el Nodo de Innovación. Este grupo asumió la tarea de investigar el quehacer innovador de la institución y el estudio de distintos marcos de referencia teórico-conceptuales sobre la innovación y la organización para ofrecer a las autoridades universitarias y la comunidad educativa en general, un diseño de sistema de innovación particular orientado a la UNED; sustentado en la aprobación de una política institucional y su respectivo plan de implementación. Esta ponencia explica la sistematización diseñada especialmente por el Nodo de Innovación, en la definición de esa propuesta de la política de innovación como sistema y que desde el mes de julio del 2017, se encuentra en discusión dentro de dos comisiones del Consejo Universitario, con la intención de ser llevada y aprobada al seno del plenario de ese órgano político colegiado

Frequency and Risk Indicators of Tooth Decay among Pregnant Women in France: A Cross-Sectional Analysis

INTRODUCTION: Little is known on the prevalence of tooth decay among pregnant women. Better knowledge of tooth decay risk indicators during pregnancy could help to develop follow-up protocols for women at risk, along with better prevention strategies. The aim of this study was to assess the frequency of tooth decay and the number of decayed teeth per woman in a large sample of pregnant women in France, and to study associated risk indicators. METHODS: A secondary cross-sectional analysis of data from a French multicentre case-control study was performed. The sample was composed of 1094 at-term women of six maternity units. A dental examination was carried out within 2 to 4 days post-partum. Socio-demographic and behavioural characteristics were obtained through a standardised interview with the women. Medical characteristics were obtained from the women's medical records. Risk indicators associated with tooth decay were identified using a negative binomial hurdle model. RESULTS: 51.6% of the women had tooth decay. The mean number of decayed teeth among women having at least one was 3.1 (s.d. = 2.8). Having tooth decay was statistically associated with lower age (aOR = 1.58, 95%CI [1.03,2.45]), lower educational level (aOR = 1.53, 95%CI [1.06,2.23]) and dental plaque (aOR = 1.75, 95%CI [1.27,2.41]). The number of decayed teeth was associated with the same risk indicators and with non-French nationality and inadequate prenatal care. DISCUSSION: The frequency of tooth decay and the number of decayed teeth among pregnant women were high. Oral health promotion programmes must continue to inform women and care providers about the importance of dental care before, during and after pregnancy. Future research should also assess the effectiveness of public policies related to oral health in target populations of pregnant women facing challenging social or economic situations