Silicon Superconducting Quantum Interference Device

We have studied a Superconducting Quantum Interference SQUID device made from a single layer thin film of superconducting silicon. The superconducting layer is obtained by heavily doping a silicon wafer with boron atoms using the Gas Immersion Laser Doping (GILD) technique. The SQUID device is composed of two nano-bridges (Dayem bridges) in a loop and shows magnetic flux modulation at low temperature and low magnetic field. The overall behavior shows very good agreement with numerical simulations based on the Ginzburg-Landau equations.Comment: Published in Applied Physics Letters (August 2015

Effects of perceived cocaine availability on subjective and objective responses to the drug

<p>Abstract</p> <p>Rationale</p> <p>Several lines of evidence suggest that cocaine expectancy and craving are two related phenomena. The present study assessed this potential link by contrasting reactions to varying degrees of the drug's perceived availability.</p> <p>Method</p> <p>Non-treatment seeking individuals with cocaine dependence were administered an intravenous bolus of cocaine (0.2 mg/kg) under 100% ('unblinded'; N = 33) and 33% ('blinded'; N = 12) probability conditions for the delivery of drug. Subjective ratings of craving, high, rush and low along with heart rate and blood pressure measurements were collected at baseline and every minute for 20 minutes following the infusions.</p> <p>Results</p> <p>Compared to the 'blinded' subjects, their 'unblinded' counterparts had similar craving scores on a multidimensional assessment several hours before the infusion, but reported higher craving levels on a more proximal evaluation, immediately prior to the receipt of cocaine. Furthermore, the 'unblinded' subjects displayed a more rapid onset of high and rush cocaine responses along with significantly higher cocaine-induced heart rate elevations.</p> <p>Conclusion</p> <p>These results support the hypothesis that cocaine expectancy modulates subjective and objective responses to the drug. Provided the important public health policy implications of heavy cocaine use, health policy makers and clinicians alike may favor cocaine craving assessments performed in the settings with access to the drug rather than in more neutral environments as a more meaningful marker of disease staging and assignment to the proper level of care.</p

Deep learning-based defect detection in industrial CT volumes of castings

International audienceIndustrial X-ray computed tomography (CT) has proven to be one of the most powerful non-destructive testing (NDT) methods for the inspection of light metal castings. The generated CT volume allows for the internal and external geometry of the specimen to be measured, casting defects to be localised and their statistical properties to be investigated. On the other hand, CT volumes are very prone to artefacts that can be mistaken for defects by conventional segmentation algorithms. These artefacts require trained operators to distinguish them from real defects, which makes CT inspection very time consuming if it is to be implemented on the production line. Foundries using this inspection method are constantly looking for a module that can perform this interpretation automatically. Based on CT data of aluminium alloy automotive and aerospace specimens provided by industrial partners, an automated approach for the analysis of discontinuities inside CT volumes is developed in this paper based on a two-stage pipeline: 2D segmentation of CT slices with automatic deep segmentation using U-Net to detect suspicious greyscale discontinuities; and classification of these discontinuities into true alarms (defects) or false alarms (artefacts and noise) using a new convolutional neural network classifier called CT-Casting-Net. The choice of each model and the training results are presented and discussed, as well as the efficiency of the approach as an automatic defect detection algorithm for industrial CT volumes using metrics relevant to the field of non-destructive testing. The approach is tested on six new CT volumes with 301 defects and achieves an object-level recall of 99%, a precision of 87% and a voxel-level intersection-over-union (IoU) of 62%

Tomographie par diffusion Rayleigh et Compton avec reconstruction numérique de l'image

La diffusion des rayons X par effets Rayleigh et Compton permet d'obtenir des tomographies de la matière inerte ou vivante. Nous décrivons un nouveau système d'acquisition en tomographie par diffusion et sa méthode de reconstruction. Le déplacement de l'objet est similaire à celui utilisé avec les tomographes de première génération. Un algorithme de reconstruction standard donne deux images intermédiaires, correspondant aux contributions Rayleigh et Compton. Des artefacts de type "cupping effect", dûs à l'auto-atténuation des photons dans l'échantillon, sont présents sur chacune de ces deux images. En faisant le rapport de ces deux images intermédiaires, on obtient une cartographie, dénuée de tout artefact, représentant le numéro atomique local de l'objet contrôlé, indépendamment de sa densité. Les expériences ont été réalisées à 1'ESRF (European Synchrotron Radiation Facility) de Grenoble, sur la ligne ID 15 B. L'important flux de photons monochromatiques (1012 ph.s-1.mm-2) permet d'obtenir des temps d'acquisition courts (quelques secondes par mesure) et d'avoir une bonne résolution spatiale. La taille du voxel est de 1x1 mm2 dans le plan de coupe pour une épaisseur de coupe de 0,3 mm.The detection of X-ray photons scattered through a sample by the Rayleigh and Compton processes is used to perform tomographic images. We describe a new experimental arrangement and the corresponding reconstruction method. The scanning method is similar to the one used for first generation tomographs. A standard reconstruction algorithm gives two intermediate images, corresponding to the Compton and Rayleigh contributions. On both images artifacts are present, due to photon attenuation in the sample. Dividing those two images produces a map, free from artifacts, which represents the atomic number Z, independently from density. The experiments were carried out at the European Synchrotron Radiation Facility (ESRF), in Grenoble (France), on line ID15 B. Due to the very high photon flux (1012 ph.s-1.mm-2), short measurement times (about a few seconds per point) are allowed, as well as a good spatial resolution. The voxel size is 1 x 1 mm2 in the plane of the slice and 0.3 mm in the third direction

Fast and robust ray casting algorithms for virtual X-ray imaging

International audienc

Conception of a high resolution x‐ray computed tomography device; application to damage initiation imaging inside materials

International audienceno abstrac

Human DNA polymerase mu (Pol μ) exhibits an unusual replication slippage ability at AAF lesion

We analyzed the ability of various cell extracts to extend a radiolabeled primer past an N-2-acetylaminofluorene (AAF) adduct located on a primed single-stranded template. When the 3′ end of the primer is located opposite the lesion, partially fractionated human primary fibroblast extracts efficiently catalyzed primer-terminus extension by adding a ladder of about 15 dGMPs, in an apparently non-templated reaction. This activity was not detected in SV40-transformed fibroblasts or in HeLa cell extracts unless purified human DNA polymerase mu (Pol µ) was added. In contrast, purified human Pol µ alone could only add three dGMPs as predicted from the sequence of the template. These results suggest that a cofactor(s) present in cellular extracts modifies Pol µ activity. The production of the dGMP ladder at the primer terminus located opposite the AAF adduct reveals an unusual ability of Pol µ (in conjunction with its cofactor) to perform DNA synthesis from a slipped intermediate containing several unpaired bases.This work was supported by European Contract no. QLG1-CT 1999-00181