Influence of mesostructuration on the reactivity of bioactive glasses in biological medium: a PIXE-RBS study

Building mesostructured biomaterials is a challenging and exciting task that has attracted much attention because of their use as drug carriers or drug delivery systems. In the case of bioactive materials, the mesostructuration can also deeply impact their physico-chemical properties and the reactivity. In this study, we show how highly ordered mesoporosity influences the early steps of the biomineralization process and the reactivity in binary (SiO2–CaO) and ternary (SiO2–CaO–P2O5) bioactive glasses. Conventional porous sol–gel glasses were synthesized using a classical route, while mesostructured glasses were developed using a non-ionic surfactant. Textural properties of these materials have been characterized. The in vitro biomineralization process was followed, using Particle Induced X-ray Emission (PIXE) associated to Rutherford Backscattering Spectrometry (RBS), which are efficient methods for a highly sensitive multi-elemental analysis. Elemental maps of silicon, calcium and phosphorus were obtained at a micrometer scale and revealed for the first time a bulk reactivity for mesostructured glasses. This is a major advantage over conventional glasses, for which the first steps of biomineralization are limited to the periphery of the material. Their enhanced bioactivity combined with their possible use as drug-delivery systems make them promising candidates for bone regeneration

Properties of Nb\_xTi\_{(1-x)}N thin films deposited on 300 mm silicon wafers for upscaling superconducting digital circuits

Scaling superconducting digital circuits requires fundamental changes in the current material set and fabrication process. The transition to 300 mm wafers and the implementation of advanced lithography are instrumental in facilitating mature CMOS processes, ensuring uniformity, and optimizing the yield. This study explores the properties of NbxTi(1-x)N films fabricated by magnetron DC sputtering on 300 mm Si wafers. As a promising alternative to traditional Nb in device manufacturing, NbxTi(1-x)N offers numerous advantages, including enhanced stability and scalability to smaller dimensions, in both processing and design. As a ternary material, NbxTi(1-x)N allows engineering material parameters by changing deposition conditions. The engineered properties can be used to modulate device parameters through the stack and mitigate failure modes. We report characterization of NbxTi(1-x)N films at less than 2% thickness variability, 2.4% Tc variability and 3% composition variability. The films material properties such as resistivity (140-375 {\Omega}cm) and critical temperature Tc (4.6 K - 14.1 K) are correlated with stoichiometry and morphology of the films. Our results highlight the significant influence of deposition conditions on crystallographic texture along the films and its correlation with Tc.Comment: 8 pages 8 figure

Co-conception et évaluation de scénarios agronomiques de réintroduction de légumineuses dans un territoire de Bourgogne

Ce numéro est constitué d’articles issus de la seconde édition des Rencontres Francophones sur les Légumineuses (RFL2) qui s’est tenu à Toulouse (France) les 17 et 18 octobre 2018.Legume crops can help facing current environmental and food challenges, even if their areas havedecreased since several decades. The aims of our study were (i) to design with local stakeholdersagronomic scenarios of reintroduction of legumes into a French territory, (ii) to assess these scenariosex ante, and (iii) to discuss with the stakeholders the interest and conditions of their adoption in theterritory. The stakeholders involved were agricultural stakeholders (farmers, technical advisors),stakeholders from environmental organizations (water union, national park) and researchersThe first step was the description and assessment of current and alternative crop management plans,from national statistical data and face-to-face surveys. In a second step, the current territory (cropdistribution in the territory and cropping strategies) was described with local stakeholders, and was usedas a reference. In a third step, stakeholders discussed various sets of objectives and constraints relatedto their territory. Among eight scenarios proposed by stakeholders, four scenarios were simulated withthe tool used in the Coclick’eau approach. For each scenario, this tool optimizes an alternativedistribution of crops and cropping strategies, and assesses the agronomic, socio-economic andenvironmental performances. Finally, the results were discussed with stakeholders.Les légumineuses peuvent contribuer à relever les défis environnementaux et alimentaires actuels,mais leurs surfaces cultivées ont largement diminué. Les objectifs de notre étude étaient (i) deconcevoir, avec les acteurs locaux du Plateau Langrois (Bourgogne), des scénarios agronomiques deréintroduction de légumineuses, (ii) d'évaluer ex ante ces scénarios, et (iii) de discuter les conditions deleur mise en œuvre sur ce territoire. Les acteurs ayant participé étaient issus du monde agricole(agriculteurs, conseillers techniques), de l’environnement (syndicat d’eau, Parc National) et de larecherche.La première étape a consisté à décrire et évaluer les itinéraires techniques actuels et prospectifs à partirde données statistiques et de résultats d’enquêtes individuelles. Dans un second temps unereprésentation du territoire actuel (assolement de cultures et de façons de cultiver) a été construite avecles acteurs et nous a servi de point de référence. Les acteurs ont ensuite exprimé leurs attendus pource territoire. Parmi les huit pistes de scénarios ayant émergé, quatre ont fait l’objet d’une simulationavec l'outil Coclick'eau, qui optimise, pour chacun de ces scénarios, un assolement alternatif et calculeses performances agronomiques, socio-économiques et environnementales. Finalement, ces résultatsont été présentés et discutés avec les acteurs

GWAS in the SIGNAL/PHARE clinical cohort restricts the association between the FGFR2 locus and estrogen receptor status to HER2-negative breast cancer patients

International audienceGenetic polymorphisms are associated with breast cancer risk. Clinical and epidemiological observations suggest that clinical characteristics of breast cancer, such as estrogen receptor or HER2 status, are also influenced by hereditary factors. To identify genetic variants associated with pathological characteristics of breast cancer patients, a Genome Wide Association Study was performed in a cohort of 9365 women from the French nationwide SIGNAL/PHARE studies (NCT00381901/RECF1098). Strong association between the FGFR2 locus and ER status of breast cancer patients was observed (ER-positive n=6211, ER-negative n=2516; rs3135718 OR=1.34 p=5.46x10-12). This association was limited to patients with HER2-negative tumors (ER-positive n=4267, ER-negative n=1185; rs3135724 OR=1.85 p=1.16x10-11). The FGFR2 locus is known to be associated with breast cancer risk. This study provides sound evidence for an association between variants in the FGFR2 locus and ER status among breast cancer patients, particularly among patients with HER2-negative disease. This refinement of the association between FGFR2 variants and ER-status to HER2-negative disease provides novel insight to potential biological and clinical influence of genetic polymorphisms on breast tumors

Influence of Mg doping on the early steps of physico-chemical reactivity of sol-gel derived bioactive glasses in biological medium.

International audienceThe aim of this study is to highlight the influence of magnesium doping on the surface reactivity of binary (SiO(2)-CaO) and ternary (SiO(2)-CaO-P(2)O(5)) bioactive glasses, prepared by sol-gel chemistry, in biological conditions. These materials were produced in powder form, and their compositional and textural properties characterized. They were then soaked in biological fluids for different delays from 0 to 4 days. The surface changes were characterized using Particles Induced X-ray Emission (PIXE) associated with Rutherford Backscattering Spectroscopy (RBS), which are efficient methods for multi-elemental analysis. Elemental maps of major and trace elements were obtained at a micrometer scale and revealed the formation of a calcium phosphate-rich layer after a few days of interaction. We demonstrate that the presence of magnesium in the material has an impact on the development and the formation rate of the bone-like apatite layer

Fine tuning of bioactivity of bioceramics through porosity engineering: a soft chemistry approach

When bioactive glasses are in contact with living tissues, several physico-chemical reactions take place at the material/bone interface, and lead to the formation of a phosphocalcic layer whose composition is close to the mineral phase of bone (hydroxyapatite). This layer is used as a mineralization site for cells and finally allows an intimate bond between the bioactive glass and osseous tissues. This binding is typical of bioactivity, which can be modulated through several parameters of the glass, like composition and textural properties. In this work we present clear evidence of the effect of porosity on the bioactivity of sol-gel derived glasses. Using templating techniques (surfactants and polystren beads respectively), both mesostructured and organized macroporous glasses have been prepared. A nice 3D organization of pores is observed for all glasses by using X-ray diffraction and TEM. Textural properties have been determined using gas sorption and themoporosimetry. Interactions between biological medium and the different glasses have been studied for different delays. At each time period, quantitative chemical maps of samples were recorded by Particle Induced X-ray Emission coupled to Rutherford Backscattering spectroscopy. This technique allows monitoring spatial and chronological evolutions of elemental concentrations, thanks to the excellent sensitivity. The influence of porosity on the bioactivity has been determined and key parameters have been determined

3D Organized Macroporous Bioactive Glasses: a Study of Pore Size Effect on Physicochemical Reactivity by Micro-PIXE-RBS.

International audienceMacroporous biomaterials have attracted much attention during the past decade because of the large range of associated applications (from drug delivery to tissue engineering). The present study focuses on the correlations between macropore size (from 400 to 1500 nm in diameter) and the early steps of biomineralization process and the reactivity in binary (SiO2-CaO) and ternary (SiO2-CaO-P2O5) bioactive glasses. Macrostructured glasses were elaborated by combining sol-gel chemistry and an inverse opal method with polystyrene beads colloidal crystals as the template. Macroporosity of these materials has been characterized thanks to thermoporosimetry. The in vitro biomineralization process was studied using particle-induced X-ray emission (PIXE) associated with Rutherford backscattering spectrometry (RBS), which are efficient methods for a highly sensitive multielemental analysis. Thanks to elemental maps of silicon, calcium, and phosphorus obtained at a micrometer scale for various interaction times, we demonstrate that the physicochemical reactions are sensitive to macropore size, even though their kinetic is not modified. This key result is an important step to build tunable biomaterials with a highly reproducible and finely controlled response for an optimized integration in living organisms