Passive Temperature-Compensating Technique for Microstructured Fiber Bragg Gratings

The thermal drift of the characteristic wavelength of fiber Bragg gratings (FBGs) photowritten in the core of microstructured fibers (MOFs) is significantly reduced by inserting a liquid of suitable refractive index into their holes. For instance, the spectral range of variations is divided by a factor of 4 over a temperature range larger than 20\degree C in a six-hole MOF, and the maximum sensitivity is reduced. Such passive FBG temperature compensation technique is of great interest for applications involving accurate sensing free of thermal effects

Tilted Fiber Bragg Grating photowritten in microstructured optical fiber for improved refractive index measurement

International audienceWe report what we believe to be the first Tilted short-period Fiber Bragg Grating photowritten in a microstructured optical fiber for refractive index measurement. We investigate the spectral sensitivity of Tilted Fiber Bragg Grating to refractive index liquid inserted into the holes of a multimode microstructured fiber. We measure the wavelength shift of the first four modes experimentally observed when calibrated oils are inserted into the fiber holes, and thus we determine the refractive index resolution for each of these modes. Moreover, a cross comparison between experimental and simulation results of a modal analysis is performed. Two simulation tools are used, respectively based on the localized functions method and on a finite element method. All results are in very good agreement

Three-hole microstructured optical fiber for efficient Fiber Bragg Grating refractometer

International audienceWe present a photosensitive three-hole microstructured optical fiber specifically designed to improve the refractive index sensitivity of a standard Fiber Bragg Grating (FBG) sensor photowritten in the suspended Ge-doped silica core. We describe the specific photowriting procedure used to realize gratings in such a fiber. We then determine their spectral sensitivity to the refractive index changes of material filling the holes surrounding the core. The sensitivity is compared to that of standard FBGs photowritten in a six-hole fiber with a larger core diameter. We demonstrate an improvement of the sensitivity by two orders of magnitude and reach a resolution of 3 x 10-5 and 6 x 10-6 around mean refractive index values of 1.33 and 1.40, respectively

Fibre Bragg grating photowriting in microstructured optical fibres for refractive index measurement

International audienceWe report results relating to fibre Bragg grating photowriting in two kinds of Ge-doped core microstructured optical fibre devoted to sensing applications. A cross-comparison between theoretical and experimental modal field patterns is carried out. We present the first values of the spectral sensitivity of a Bragg grating in relation to the refractive index of calibrated oils inserted into the holes

NS2 Protein of Hepatitis C Virus Interacts with Structural and Non-Structural Proteins towards Virus Assembly

Growing experimental evidence indicates that, in addition to the physical virion components, the non-structural proteins of hepatitis C virus (HCV) are intimately involved in orchestrating morphogenesis. Since it is dispensable for HCV RNA replication, the non-structural viral protein NS2 is suggested to play a central role in HCV particle assembly. However, despite genetic evidences, we have almost no understanding about NS2 protein-protein interactions and their role in the production of infectious particles. Here, we used co-immunoprecipitation and/or fluorescence resonance energy transfer with fluorescence lifetime imaging microscopy analyses to study the interactions between NS2 and the viroporin p7 and the HCV glycoprotein E2. In addition, we used alanine scanning insertion mutagenesis as well as other mutations in the context of an infectious virus to investigate the functional role of NS2 in HCV assembly. Finally, the subcellular localization of NS2 and several mutants was analyzed by confocal microscopy. Our data demonstrate molecular interactions between NS2 and p7 and E2. Furthermore, we show that, in the context of an infectious virus, NS2 accumulates over time in endoplasmic reticulum-derived dotted structures and colocalizes with both the envelope glycoproteins and components of the replication complex in close proximity to the HCV core protein and lipid droplets, a location that has been shown to be essential for virus assembly. We show that NS2 transmembrane region is crucial for both E2 interaction and subcellular localization. Moreover, specific mutations in core, envelope proteins, p7 and NS5A reported to abolish viral assembly changed the subcellular localization of NS2 protein. Together, these observations indicate that NS2 protein attracts the envelope proteins at the assembly site and it crosstalks with non-structural proteins for virus assembly

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

La perspective des éducateurs et des praticiens sur le développement d’un outil de formation par concordance pour l’externat de médecine dans le contexte de la COVID-19

Background: The COVID-19 pandemic has forced medical schools to create educational material to palliate the anticipated and observed decrease in clinical experiences during clerkships. An online learning by concordance (LbC) tool was developed to overcome the limitation of students’ experiences with clinical cases. However, knowledge about the instructional design of an LbC tool is scarce, especially the perspectives of collaborators involved in its design: 1- educators who wrote the vignettes’ questions and 2- practitioners who constitute the reference panel by answering the LbC questions. The aim of this study was to describe the key elements that supported the pedagogical design of an LbC tool from the perspectives of educators and practitioners. Methods: A descriptive qualitative research design has been used. Online questionnaires were used, and descriptive analysis was conducted. Results: Six educators and 19 practitioners participated in the study.  Important to the educators in designing the LbC tool were prevalent or high-stake situations, theoretical knowledge, professional situations experienced and perceived difficulties among students, and that the previous workshop promoted peer discussion and helped solidify the writing process. Important for practitioners was standards of practice and consensus among experts. However, they were uncertain of the educational value of their feedback, considering the ambiguity of the situations included in the LbC tool.  Conclusions: The LbC tool is a relatively new training tool in medical education. Further research is needed to refine our understanding of the design of such a tool and ensure its content validity to meet the pedagogical objectives of the clerkship.Contexte : Face à la pandémie de la COVID-19, les facultés de médecine ont été contraintes à créer du matériel pédagogique pouvant pallier la diminution prévue et avérée de l’exposition clinique pendant les stages d’externat. Un outil numérique de formation par concordance (FpC) a été développé pour combler le manque d’exposition à des cas cliniques. Cependant, les connaissances sur la conception pédagogique des outils de FpC sont limitées, en particulier en ce qui concerne les perspectives des collaborateurs participant à leur réalisation : 1 – les éducateurs qui rédigent les questions des vignettes et 2 – les praticiens composant le groupe d’experts qui fournissent les réponses de référence aux questions de FpC. L’objectif de cette étude était de décrire les éléments clés qui ont étayé la conception pédagogique d’un outil FpC du point de vue des éducateurs et des praticiens. Méthodes : Il s’agit d’une recherche qualitative de type descriptif, pour laquelle on s’est servi de questionnaires en ligne et d’une méthode d’analyse descriptive. Résultats : Six éducateurs et 19 praticiens ont participé à l’étude. Dans la conception de l’outil FpC, les éducateurs ont attribué une importance particulière aux situations courantes ou à enjeu élevé, aux connaissances théoriques, aux situations professionnelles vécues par les étudiants et aux difficultés qu’ils ont perçues chez eux. Ils ont également tenu à faire en sorte que l’atelier qui précédait la conception favorise le débat entre pairs et contribue à solidifier le processus de rédaction. Les praticiens ont privilégié les normes de pratique et l’existence d’un consensus entre experts. Cependant, ils doutaient de la valeur pédagogique de leurs commentaires, compte tenu de l’ambiguïté des situations décrites dans l’outil FpC. Conclusions : Les outils FpC sont relativement nouveaux en éducation médicale. Des recherches plus poussées sont nécessaires pour affiner notre compréhension de la conception d’un tel outil et pour nous assurer de sa validité de contenu, pour bien répondre aux objectifs pédagogiques de l’externat

Estimation of driver awareness of pedestrian based on Hidden Markov Model

International audience; Understanding driver behaviors is an important need for the Advanced Driver Assistance Systems. In particular, the pedestrian detection systems become extremely distracting and annoying when they inform the driver with unnecessary warning messages. In this paper, we propose to study the driver behaviors whenever a pedestrian appears in front of the vehicle. A method based on the driving actions and the Hidden Markov Model (HMM) algorithm is developed to classify the driver awareness of pedestrian and the driver unawareness of pedestrian. The method is successfully validated using the collected data from the experiments that are conducted on a driving simulator. Furthermore, two simple methods based on the static parameters such as the Time-To-Collision and the Required Deceleration Parameter are also applied to our problem and are compared to the proposed method. The result shows a significant improvement of the HMM-based method compared to the simple ones