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X-ray imaging is widely used in non-destructive testing dedicated to industry, medical or security domain. In aircraft production, the aerospace industry increasingly integrates carbon fibre reinforced polymers (CFRP), which may develop defects from operational wear, like lightning strikes. To robustly characterize density changes resulting from induced lightning damage in CFRP, multilateral shearing interferometry (MLSI) – a phase imaging technique – have been incorporated on a X-ray laboratory bench. Indeed, such method provides higher contrasts than X-ray attenuation imaging for composite materials and brings complementary information of the imaged sample. However, extracting the phase signal requires conditions of the imaging system and algorithmic strategies, which can lead to the emergence of artifacts in phase images. This thesis work involved the characterisation of these artifacts in the context of MLSI applied to X-ray phase imaging, as well as the development of tracking methods and corrective strategies.

Cette communication présente des résultats de spectrométrie par fluorescence X à dispersion d’énergie (ED-XRF) acquis durant des procédés de fabrication additive métallique. Cette technique de caractérisation sans contact et non-destructive est appliquée à deux techniques de fabrication additive métallique. Le but est de renforcer la maitrise de ces procédés et de répondre à des exigences de contrôle qualité. Deux cas d’études sont abordés, l’un concernant des mesures effectuées sur des échantillons possédant une gradation de la composition chimique de l’alliage, l’autre présentant le monitoring des fumées induites durant un procédé de fabrication additive.

Grade2XL is a European project funded by the H2020 program that gathers 21 academic and industrial partners. Started in March 2020 for 4 years, the principal objective is to print extra-large structures using the WAAM (Wire Arc Additive Manufacturing) method with a complete control of the fabrication process. Since WAAM is a relatively new technology for printing large specimens, it is important to develop quality assurance methods that can be used during the fabrication and once the structure has been built, which is the focus of CEA List in the project. Regarding methods applied built structures, CEA List has investigated Resonant Ultrasound Spectroscopy (RUS) for the material characterization and more specifically the evaluation of the elastic constants or more conventional ones for the inspection with phased-array ultrasonic techniques (PAUT) or eddy current (EC) for the detection of indications are implemented and optimised them for the inspection of the final structures. Concerning the development of in-line monitoring methods, CEA List has been working on laser Doppler vibrometry (LDV) and X-ray fluorescence (XRF) spectrometry, in order to get structural information during the printing but also detect the appearance of abnormal events and correlate them to the appearance of defects generated during the WAAM process. This proceeding presents the advantages of those methods for the inspection of extra-large structures made by WAAM and discusses the first results obtained in the framework of the project. Keywords: Additive Manufacturing, NDT, Imaging techniques, Eddy current, In-line monitoring, laser vibrometry, X-ray fluorescence spectrometry, Resonant Ultrasound Spectroscopy.

Le contraste de phase en imagerie par rayons X permet de voir des détails de structures dans les matériaux peu absorbants. Plusieurs techniques existent mais l’interférométrie à décalage multilatérale (IDML) permet une mesure simultanée des gradients de phase selon plusieurs directions par un post-traitement dans le domaine de Fourier. Dans cet article nous présentons des résultats de cette méthode sur deux types de matériaux, des polymères issus de fabrication additive biosourcée et des composites carbonés utilisés dans l’aéronautique. Des outils d’analyse d’image sont mis en oeuvre sur les images obtenues.

We present an in-situ energy dispersive X-ray fluorescence measurement of the content of Chromium and Nickel in the fumes produced by selective laser melting on an Inconel 625 powder. Significant variations of the intensities of the Chromium and Nickel Kα fluorescence lines were evidenced as a function of the laser power, lasing velocity and chamber atmosphere. Calibration has been carried out using Monte–Carlo particle transport simulations allowed to obtain a quantitative estimate of the Chromium and Nickel mass fraction in the fumes. The experimental data has been compared to the predictions of an analytical physico-chemical model with consistent results. This approach thus also allows to provide information on the temperature of the metallic bath.

Abstract Background Technological advancements in the era of massive parallel sequencing have enabled the functional dissection of the human transcriptome. However, 5′ ends of mRNAs are significantly underrepresented in these datasets, hindering the efficient analysis of the complex human transcriptome. The implementation of the template-switching mechanism at the reverse transcription stage along with 5′ rapid amplification of cDNA ends (RACE) constitutes the most prominent and efficient strategy to specify the actual 5′ ends of cDNAs. In the current study, we developed a 5′ RACE-seq method by coupling a custom template-switching and 5′ RACE assay with targeted nanopore sequencing, to accurately unveil 5′ termini of mRNA targets. Results The optimization of the described 5′ RACE-seq method was accomplished using the human BCL2L12 as control gene. We unveiled that the selection of hybrid DNA/RNA template-switching oligonucleotides as well as the complete separation of the cDNA extension incubation from the template-switching process, significantly increase the overall efficiency of the downstream 5′ RACE. Collectively, our results support the existence of two distinct 5′ termini for BCL2L12, being in complete accordance with the results derived from both direct RNA and PCR-cDNA sequencing approaches from Oxford Nanopore Technologies. As proof of concept, we implemented the described 5′ RACE-seq methodology to investigate the 5′ UTRs of several kallikrein-related peptidases (KLKs) gene family members. Our results confirmed the existence of multiple annotated 5′ UTRs of the human KLK gene family members, but also identified novel, previously uncharacterized ones. Conclusions In this work we present an in-house developed 5′ RACE-seq method, based on the template-switching mechanism and targeted nanopore sequencing. This approach enables the broad and in-depth study of 5′ UTRs of any mRNA of interest, by offering a tremendous sequencing depth, while significantly reducing the cost-per reaction compared to commercially available kits.

Abstract The burden of antibiotic resistance is currently estimated by mathematical modeling, without real count of resistance to key antibiotics. Here we report the real rate of resistance to key antibiotics in bacteria isolated from humans during a 5 years period in a large area in southeast in France. We conducted a retrospective study on antibiotic susceptibility of 539,107 clinical strains isolated from hospital and private laboratories in south of France area from January 2014 to January 2019. The resistance rate to key antibiotics as well as the proportion of bacteria classified as Difficult-to-Treat (DTR) were determined and compared with the Mann–Whitney U test, the χ2 test or the Fisher’s exact test. Among 539,037 isolates, we did not observe any significant increase or decrease in resistance to key antibiotics for 5 years, (oxacillin resistance in Staphylococcus aureus, carbapenem resistance in enterobacteria and Pseudomonas aeruginosa and 3rd generation cephalosporin resistance in Escherichia coli and Klebsiella pneumoniae). However, we observed a significant decrease in imipenem resistance for Acinetobacter baumannii from 2014 to 2018 (24.19–12.27%; p = 0.005) and a significant increase of ceftriaxone resistance in Klebsiella pneumoniae (9.9–24.03%; p = 0.001) and Enterobacter cloacae (24.05–42.05%; p = 0.004). Of these 539,037 isolates, 1604 (0.3%) had a DTR phenotype. Over a 5-year period, we did not observe a burden of AR in our region despite a high rate of antibiotic consumption in our country. These results highlight the need for implementation of real-time AR surveillance systems which use factual data.

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