Implementation of ultrasonic sensing for high resolution measurement of binary gas mixture fractions

We describe an ultrasonic instrument for continuous real-time analysis of the fractional mixture of a binary gas system. The instrument is particularly well suited to measurement of leaks of a high molecular weight gas into a system that is nominally composed of a single gas. Sensitivity < 5 × 10−5 is demonstrated to leaks of octaflouropropane (C3F8) coolant into nitrogen during a long duration (18 month) continuous study. The sensitivity of the described measurement system is shown to depend on the difference in molecular masses of the two gases in the mixture. The impact of temperature and pressure variances on the accuracy of the measurement is analysed. Practical considerations for the implementation and deployment of long term, in situ ultrasonic leak detection systems are also described. Although development of the described systems was motivated by the requirements of an evaporative fluorocarbon cooling system, the instrument is applicable to the detection of leaks of many other gases and to processes requiring continuous knowledge of particular binary gas mixture fractions

Role of cytoskeletal abnormalities in the neuropathology and pathophysiology of type I lissencephaly

Type I lissencephaly or agyria-pachygyria is a rare developmental disorder which results from a defect of neuronal migration. It is characterized by the absence of gyri and a thickening of the cerebral cortex and can be associated with other brain and visceral anomalies. Since the discovery of the first genetic cause (deletion of chromosome 17p13.3), six additional genes have been found to be responsible for agyria–pachygyria. In this review, we summarize the current knowledge concerning these genetic disorders including clinical, neuropathological and molecular results. Genetic alterations of LIS1, DCX, ARX, TUBA1A, VLDLR, RELN and more recently WDR62 genes cause migrational abnormalities along with more complex and subtle anomalies affecting cell proliferation and differentiation, i.e., neurite outgrowth, axonal pathfinding, axonal transport, connectivity and even myelination. The number and heterogeneity of clinical, neuropathological and radiological defects suggest that type I lissencephaly now includes several forms of cerebral malformations. In vitro experiments and mutant animal studies, along with neuropathological abnormalities in humans are of invaluable interest for the understanding of pathophysiological mechanisms, highlighting the central role of cytoskeletal dynamics required for a proper achievement of cell proliferation, neuronal migration and differentiation

Finding a Closed Boundary by Growing Minimal Paths from a Single Point on 2D or 3D Images

In this paper, we present a new method for segmenting closed contours and surfaces. Our work builds on a variant of the Fast Marching algorithm. First, an initial point on the desired contour is chosen by the user. Next, new keypoints are detected automatically using a front propagation approach. We assume that the desired object has a closed boundary. This a-priori knowledge on the topology is used to devise a relevant criterion for stopping the keypoint detection and front propagation. The final domain visited by the front will yield a band surrounding the object of interest. Linking pairs of neighboring keypoints with minimal paths allows us to extract a closed contour from a 2D image. Detection of a variety of objects on real images is demonstrated. Using a similar same idea, we can extract networks of minimal paths from a 3D image called GeodesicMeshing. The proposed method is applied to 3D data with promising results

Chemins minimaux en analyse d images (nouvelles contributions et applications à l imagerie biologique)

Initialement introduites en analyse d'images pour minimiser globalement la fonctionnelle des contours actifs géodésiques, les techniques basées sur les chemins minimaux permettent d'extraire d'une image des courbes ouvertes ou fermées de manière robuste. Numériquement, les chemins minimaux sont obtenus en résolvant l'équation Eikonale sur une grille discrète avec un algorithme rapide appelé Fast Marching. Dans cette thèse, nous présentons de nouvelles approches basées sur les chemins minimaux et montrons leur intérêt pour l'analyse d'images biologiques. Cette thèse comporte trois parties. Dans la première partie, nous dressons un état de l'art des modèles déformables basés frontières et des méthodes basées sur les chemins minimaux proposées jusqu'ici dans la littérature. Dans la deuxième partie, nous proposons une nouvelle approche pour automatiquement détecter et suivre, dans des séquences d'images de fluorescence 2D, des objets ponctuels visibles par intermittence. Les trajectoires des objets en mouvement, assimilées à des chemins minimaux définis dans un espace spatiotemporel, sont reconstruites avec une technique de groupement perceptuel basée sur une propagation de fronts dans le volume 2D+T. Dans une troisième partie, nous nous intéressons à l'extraction de surfaces dans des images 3D. Nous introduisons d'abord une approche par propagation de fronts permettant de paver une surface fermée par un ensemble de points. Nous proposons ensuite une méthode pour extraire un patch de surface à partir d'un point en construisant un réseau dense de chemins minimaux, puis étendons cette méthode afin d'extraire une surface fermée, de manière rapide et robuste, à partir de quelques points de surface.Introduced first in image analysis to globally minimize the geodesic active contour functionnal, minimal paths techniques are robust tools for extracting open and closed contours from images. Minimal paths are computed by solving the Eikonal equation on a discrete grid with an efficient algorithm called Fast Marching. In this thesis, we present novel approaches based on minimal paths. The interest of these techniques is illustrated by the analysis of biological images. This thesis consists of three parts. In the first part, we review the relevant litterature in boundary-based deformable models and minimal paths techniques. In the second part, we propose a new approach for automatically detecting and tracking, in sequences of 2D fluorescence images, punctual objects which are intermittently visible. Trajectories of moving objects, considered as minimal paths in a spatiotemporal space, are retrieved using a perceptual grouping approach based on front propagation in the 2D+T volume. The third part adresses the problem of surface extraction in 3D images. First, we introduce a front propagation approach to distribute a set of points on a closed surface. Then, we propose a method to extract a surface patch from a single point by constructing a dense network of minimal paths. We finally present an extension of this method to extract a closed surface, in a fast and robust manner, from a few points lying on the surfacePARIS-DAUPHINE-BU (751162101) / SudocSudocFranceF

Mobile App for Parental Empowerment for Caregivers of Children With Autism Spectrum Disorders: Prospective Open Trial

International audienceBACKGROUND: Conflicting data emerge from literature regarding the actual use of smartphone apps in medicine; some considered the introduction of smartphone apps in medicine to be a breakthrough, while others suggested that, in real-life, the use of smartphone apps in medicine is disappointingly low. Yet, digital tools become more present in medicine daily. To empower parents of a child with autism spectrum disorder, we developed the Smartautism smartphone app, which asks questions and provides feedback, using a screen with simple curves.OBJECTIVE: The purpose of this study was to evaluate usage of the app by caregivers of individuals with autism spectrum disorders.METHODS: We conducted a prospective longitudinal exploratory open study with families that have a child with autism spectrum disorder. Data were recorded over a period of 6 months, and the outcome criteria were (1) overall response rates for a feedback screen and qualitative questionnaires, and (2) response rates by degree of completion and by user interest, based on attrition.RESULTS: Participants (n=65) had a very high intent to use the app during the 6-month period (3698/3900 instances, 94.8%); however, secondary analysis showed that only 46% of participants (30/65) had constant response rates over 50%. Interestingly, these users were characterized by higher use and satisfaction with the feedback screen when compared to low (P<.001) and moderate (P=.007) users.CONCLUSIONS: We found that real or perceived utility is an important incentive for parents who use empowerment smartphone apps.INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1136/bmjopen-2016-012135

Effect of adenosine A2A receptor activation in murine models of respiratory disorders.

Activation of the adenosine A(2A) receptor has been postulated as a possible treatment for lung inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD). In this report, we have studied the anti-inflammatory properties of the reference A(2A) agonist CGS-21680, given intranasally at doses of 10 and 100 microg/kg, in a variety of murine models of asthma and COPD. After an acute ovalbumin challenge of sensitized mice, prophylactic administration of CGS-21680 inhibited the bronchoalveolar lavage fluid inflammatory cell influx but not the airway hyperreactivity to aerosolized methacholine. After repeated ovalbumin challenges, CGS-21680 given therapeutically inhibited the bronchoalveolar lavage fluid inflammatory cell influx but had no effect on the allergen-induced bronchoconstriction, the airway hyperreactivity, or the bronchoalveolar lavage fluid mucin levels. As a comparator, budesonide given intranasally at doses of 0.1-1 mg/kg fully inhibited all the parameters measured in the latter model. In a lipopolysaccharide-driven model, CGS-21680 had no effect on the bronchoalveolar lavage fluid inflammatory cell influx or TNF-alpha, keratinocyte chemoattractant, and macrophage inflammatory protein-2 levels, but potently inhibited neutrophil activation, as measured by bronchoalveolar lavage fluid elastase levels. With the use of a cigarette smoke model of lung inflammation, CGS-21680 did not significantly inhibit bronchoalveolar lavage fluid neutrophil infiltration but reversed the cigarette smoke-induced decrease in macrophage number. Together, these results suggest that activation of the A(2A) receptor would have a beneficial effect by inhibiting inflammatory cell influx and downregulating inflammatory cell activation in asthma and COPD, respectively

Plasma membrane sterol complexation, generated by filipin, triggers signaling responses in tobacco cells

International audienceThe effects of changes in plasma membrane (PM) sterol lateral organization and availability on the control of signaling pathways have been reported in various animal systems, but rarely assessed in plant cells. In the present study, the pentaene macrolide antibiotic filipin III, commonly used in animal systems as a sterol sequestrating agent, was applied to tobacco cells. We show that filipin can be used at a non-lethal concentration that still allows an homogeneous labeling of the plasma membrane and the formation of filipin-sterol complexes at the ultrastructural level. This filipin concentration triggers a rapid and transient NADPH oxidase-dependent production of reactive oxygen species, together with an increase in both medium alkalinization and conductivity. Pharmacological inhibition studies suggest that these signaling events may be regulated by phosphorylations and free calcium. By conducting FRAP experiments using the di-4-ANEPPDHQ probe and spectrofluorimetry using the Laurdan probe, we provide evidence for a filipin-induced increase in PM viscosity that is also regulated by phosphorylations. We conclude that filipin triggers ligand-independent signaling responses in plant cells. The present findings strongly suggest that changes in PM sterol availability could act as a sensor of the modifications of cell environment in plants leading to adaptive cell responses through regulated signaling processes