Le Libre : catalyseur de l'Humanisme ?

National audienceL'ingénieur humaniste doit comprendre le monde et œuvrer à la diffusion large et sans barrières ni discrimination de la connaissance. Ce concept résonne largement avec celui de la culture libre, qui promeut la liberté de distribution des biens non matériels tels que logiciels, inventions, connaissances, etc.. Nous défendons donc dans cette communication que la sensibilisation à la culture libre est à la fois une opportunité et une nécessité pour la formation d'ingénieurs humanistes. Nous proposons également quelques pistes de réflexion pour l'intégration de cette culture libre dans notre contexte

High Tc Josephson nanoJunctions made by ion irradiation : characteristics and reproducibility

Reproducible High Tc Josephson junctions have been made in a rather simple two-step process using ion irradiation. A microbridge 1 to 5 micrometers wide is firstly designed by ion irradiating a c-axis-oriented YBa2Cu3O7 film through a gold mask such as the unprotected part becomes insulating. A lower Tc part is then defined within the bridge by irradiating with a much lower dose through a 20 nm wide narrow slit opened in a standard electronic photoresist. These planar junctions, whose settings can be finely tuned, exhibit reproducible and nearly ideal Josephson characteristics. Non hysteretic Resistively Shunted Junction (RSJ) like behavior is observed, together with sinc Fraunhofer patterns for rectangular junctions. The IcRn product varies with temperature ; it can reach a few mV. The typical resistance ranges from 0.1 to a few ohms, and the critical current density can be as high as 30 kA/cm2. The dispersion in characteristics is very low, in the 5% to 10% range. Such nanojunctions have been used to make microSQUIDs (Superconducting Quantum Interference Device) operating at Liquid Nitrogen (LN2) temperature. They exhibit a very small asymmetry, a good sensitivity and a rather low noise. The process is easily scalable to make rather complex Josephson circuits.Comment: 4 pages, 5 figures, Applied Superconductivity Conference Seattle 200

Present and future of high-temperature superconductor quantum-based voltage standards

This paper presents a brief overview of the current state-of-the-art of Josephson junctions for Quantum-based Voltage Standards fabricated with High-Temperature Superconductors (HTS). A short introduction on the history and technical evolution of Low Temperature Superconductors (LTS) technology is provided for non-specialists. Then HTS technology is summarized and discussed in the context of quantum voltage standard applications. Finally, the two most promising technologies: bicrystal and Focused Helium-Ion Beam junctions are discussed with more detail, analyzing strength, limitations and perspectives in both cases

Engineering two-dimensional superconductivity and Rashba spin-orbit coupling in LaAlO/SrTiO quantum wells by selective orbital occupancy

The discovery of two-dimensional electron gases (2DEGs) at oxide interfaces-involving electrons in narrow d -bands-has broken new ground, enabling the access to correlated states that are unreachable in conventional semiconductors based on s - and p - electrons. There is a growing consensus that emerging properties at these novel quantum wells-such as 2D superconductivity and magnetism-are intimately connected to specific orbital symmetries in the 2DEG sub-band structure. Here we show that crystal orientation allows selective orbital occupancy, disclosing unprecedented ways to tailor the 2DEG properties. By carrying out electrostatic gating experiments in LaAlO₃/SrTiO₃ wells of different crystal orientations, we show that the spatial extension and anisotropy of the 2D superconductivity and the Rashba spin-orbit field can be largely modulated by controlling the 2DEG sub-band filling. Such an orientational tuning expands the possibilities for electronic engineering of 2DEGs at LaAlO₃/SrTiO₃ interfaces. Two-dimensional electron gases at oxide interfaces induce exotic behaviours. By studying samples with different crystal orientation, Herranz et al. show that the extension and anisotropy of the oxide quantum well properties can be controlled through selective sub-band filling via orientational tuning

Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus

A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 × 10-20), ER-negative BC (P=1.1 × 10-13), BRCA1-associated BC (P=7.7 × 10-16) and triple negative BC (P-diff=2 × 10-5). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 × 10-3) and ABHD8 (P<2 × 10-3). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3′-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk

Identification of 12 new susceptibility loci for different histotypes of epithelial ovarian cancer.

To identify common alleles associated with different histotypes of epithelial ovarian cancer (EOC), we pooled data from multiple genome-wide genotyping projects totaling 25,509 EOC cases and 40,941 controls. We identified nine new susceptibility loci for different EOC histotypes: six for serous EOC histotypes (3q28, 4q32.3, 8q21.11, 10q24.33, 18q11.2 and 22q12.1), two for mucinous EOC (3q22.3 and 9q31.1) and one for endometrioid EOC (5q12.3). We then performed meta-analysis on the results for high-grade serous ovarian cancer with the results from analysis of 31,448 BRCA1 and BRCA2 mutation carriers, including 3,887 mutation carriers with EOC. This identified three additional susceptibility loci at 2q13, 8q24.1 and 12q24.31. Integrated analyses of genes and regulatory biofeatures at each locus predicted candidate susceptibility genes, including OBFC1, a new candidate susceptibility gene for low-grade and borderline serous EOC