The identification of a new genotype of avian paramyxoviruses type I in West-Africa provides new outcomes for phylogeny reconstruction

International audienc

Pressure Dependence of the Frequency Permeability Spectra of Soft Ferrite Composite Materials: A Method of Measuring the Natural Ferromagnetic Resonance Frequency

International audienceExperimental studies on the complex susceptibility of soft magnetic composite materials (magnetostrictive Ni-Zn and Ni-Zn-Co spinels) in their region of ferrimagnetic resonance (FMR) show that the FMR is an increasing function of the applied pressure. It is shown that powders could advantageously replace their sintered materials counterpart to measure without any ambiguity the natural ferrimagnetic resonance (NFMR) frequencies of bulk materials. It is also shown that such soft ferrite composites can be realized in order to shift FMR to higher values, and to obtain low magnetic losses up to 900 MHz. High frequencies applications can be envisaged

Influence de ferrites de Ni-Zn dans la miniaturisation d'antennes pour applications DVB-H.

National audienceCette étude se situe dans la problématique de la miniaturisation d'antennes dans le domaine de fréquences 470-862MHz, correspondant à la norme DVB-H. Dans cet objectif les propriétés magnétostrictives de ferrites de Ni-Zn sont mises à profit pour étendre jusqu'à 1 GHz leur potentialité d'application comme substrats d'antennes. Les matériaux réalisés présentent des tangentes de pertes magnétiques qui restent inférieures à 5.10-2 dans la gamme de fréquence 100MHZ-1GHz, avec une perméabilité constante et un indice optique proche de 3 pour le matériau présenté Cette valeur pourra être aisément augmentée jusqu'à 4,5 environ. Ces propriétés prédisposent ces matériaux aux applications dans le domaine UHF

Taming Friedrich-Wintgen interference in resonant metasurface: vortex laser emitting at on-demand tilted-angle

Friedrich-Wintgen (FW) interference is an atypical coupling mechanism that grants loss exchange between leaky resonances in non-Hermitian classical and quantum systems. Intriguingly, such an mechanism makes it possible for destructive interference scenario in which a radiating wave becomes a bound state in the continuum (BIC) by giving away all of its losses. Here we propose and demonstrate experimentally an original concept to tailor FW-BICs as polarization singularity at on-demand wavevectors in optical metasurface. As a proof-of-concept, using hybrid organic-inorganic halide perovskite as active material, we empower this novel polarization singularity to obtain lasing emission exhibiting both highly directional emission at oblique angles and polarization vortex in momentum space. Our results pave the way to steerable coherent emission with tailored polarization pattern for applications in optical communication/manipulation in free-space, high-resolution imaging /focusing and data storage

Computer design of obligate heterodimer meganucleases allows efficient cutting of custom DNA sequences

Meganucleases cut long (>12 bp) unique sequences in genomes and can be used to induce targeted genome engineering by homologous recombination in the vicinity of their cleavage site. However, the use of natural meganucleases is limited by the repertoire of their target sequences, and considerable efforts have been made to engineer redesigned meganucleases cleaving chosen targets. Homodimeric meganucleases such as I-CreI have provided a scaffold, but can only be modified to recognize new quasi-palindromic DNA sequences, limiting their general applicability. Other groups have used dimer-interface redesign and peptide linkage to control heterodimerization between related meganucleases such as I-DmoI and I-CreI, but until now there has been no application of this aimed specifically at the scaffolds from existing combinatorial libraries of I-CreI. Here, we show that engineering meganucleases to form obligate heterodimers results in functional endonucleases that cut non-palindromic sequences. The protein design algorithm (FoldX v2.7) was used to design specific heterodimer interfaces between two meganuclease monomers, which were themselves engineered to recognize different DNA sequences. The new monomers favour functional heterodimer formation and prevent homodimer site recognition. This design massively increases the potential repertoire of DNA sequences that can be specifically targeted by designed I-CreI meganucleases and opens the way to safer targeted genome engineering

Definition and diagnostic methods for Barrett’s esophagus

L’oesophage de Barrett ou endobrachyoesophage (EBO) est le remplacement de la muqueuse malpighienne de l’oesophage par une métaplasie glandulaire. Son diagnostic repose sur la combinaison d’une suspicion endoscopique et d’une confirmation histologique. L’EBO est un facteur de risque reconnu de l’adénocarcinome oesophagien, et il est considéré comme une condition pré-cancéreuse pouvant évoluer chez certains patients selon une séquence métaplasie – dysplasie – cancer. Du fait de son potentiel dégénératif, une surveillance endoscopique est souvent préconisée en l’absence de contre-indication à un traitement éventuel du fait du terrain. Cette surveillance vise à dépister des lésions pré-cancéreuses ou cancéreuses précoces à un stade curable. Dans cette revue générale, nous rappelons la définition de Montréal, la classification endoscopique de Prague, ainsi que les nouvelles modalités endoscopiques de dépistage et de surveillance de l’EBO.Barrett’s esophagus (BE) is a metaplastic change of the lining of the esophagus characterized by the replacement of normal squamous epithelium by a glandular epithelium. The diagnosis of BE requires both an endoscopic suspicion of esophageal metaplasia (ESEM) and a histological proof of gastric or intestinal metaplasia. BE is an established risk factor for esophageal adenocarcinoma, according to a metaplasia – low dysplasia – adenocarcinoma sequence. Therefore, an endoscopic surveillance is frequently recommended in patients without any contra-indication for potential treatment (e.g. associated life-threatening disorders). This surveillance aims at diagnosing early cancerous lesions at a curable stage. In this review, we focus on the Montreal definition, the Prague endoscopic classification and new endoscopic modalities for screening and surveillance of BE