Incorporation of H_2 in vitreous silica, qualitative and quantitative determination from Raman and infrared spectroscopy

Incorporation mechanisms of H_2 in silica glass were studied with Raman and infrared (IR) microspectroscopy. Hydrogenated samples were prepared at temperatures between 800 deg C and 955 deg C at 2 kbar total pressure. Hydrogen fugacities (f_{H_2}) were controlled using the double capsule technique with the iron-w\"ustite (IW) buffer assemblage generating f_{H_2} of 1290-1370 bars corresponding to H_2 partial pressures (P_{H_2}) of 960-975 bars. We found that silica glass hydrogenated under such conditions contains molecular hydrogen (H_2) in addition to SiH and SiOH groups. H_2 molecules dissolved in the quenched glasses introduce a band at 4136 cm^{-1} in the Raman spectra which in comparison to that of gaseous H_2 is wider and is shifted to lower frequency. IR spectra of hydrogenated samples contain a band at 4138 cm^{-1} which we assign to the stretching vibration of H_2 molecules located in non-centrosymmetric sites. The Raman and IR spectra indicate that the dissolved H_2 molecules interact with the silicate network. We suggest that the H_2 band is the envelope of at least three components due to the occupation of at least three different interstitial sites by H_2 molecules. Both, Raman and IR spectra of hydrogenated glasses contain bands at ~2255 cm^{-1} which may be due to the vibration of SiH groups

Coupled visco-mechanical and diffusion void growth modelling during composite curing

Most critical processing step during long fiber reinforced epoxy matrix composite laminate manufacturing is the polymerization stage. If not optimized, it gives birth to defects in the bulk material, such as voids. These defects are considered as possible sources of damage in the composite parts. The aim of this work is to model the evolution of void growth in thermoset composite laminates after ply collation (autoclave processes) or resin impregnation (RTM, LCM process). A coupled mechanical and diffusion model is presented to better predict the final void size at the end of polymerization. Amongst the parameter investigated, onset of pressure application and diffusive species concentration where found to have a major effect on void size evolution during curing process

Eco: A Hardware-Software Co-Design for In Situ Power Measurement on Low-end IoT Systems

Energy-constrained sensor nodes can adaptively optimize their energy consumption if a continuous measurement exists. This is of particular importance in scenarios of high dynamics such as energy harvesting or adaptive task scheduling. However, self-measuring of power consumption at reasonable cost and complexity is unavailable as a generic system service. In this paper, we present Eco, a hardware-software co-design enabling generic energy management on IoT nodes. Eco is tailored to devices with limited resources and thus targets most of the upcoming IoT scenarios. The proposed measurement module combines commodity components with a common system interfaces to achieve easy, flexible integration with various hardware platforms and the RIOT IoT operating system. We thoroughly evaluate and compare accuracy and overhead. Our findings indicate that our commodity design competes well with highly optimized solutions, while being significantly more versatile. We employ Eco for energy management on RIOT and validate its readiness for deployment in a five-week field trial integrated with energy harvesting

FlexClock: Generic Clock Reconfiguration for Low-end IoT Devices

Clock configuration within constrained general-purpose microcontrollers takes a key role in tuning performance, power consumption, and timing accuracy of applications in the Internet of Things (IoT). Subsystems governing the underlying clock tree must nonetheless cope with a huge parameter space, complex dependencies, and dynamic constraints. Manufacturers expose the underlying functions in very diverse ways, which leads to specialized implementations of low portability. In this paper, we propose FlexClock, an approach for generic online clock reconfiguration on constrained IoT devices. We argue that (costly) generic clock configuration of general purpose computers and powerful mobile devices need to slim down to the lower end of the device spectrum. In search of a generalized solution, we identify recurring patterns and building blocks, which we use to decompose clock trees into independent, reusable components. With this segmentation we derive an abstract representation of vendor-specific clock trees, which then can be dynamically reconfigured at runtime. We evaluate our implementation on common hardware. Our measurements demonstrate how FlexClock significantly improves peak power consumption and energy efficiency by enabling dynamic voltage and frequency scaling (DVFS) in a platform-agnostic way

Quelle est l'activité du TRM en protonthérapie ?: observation et analyse de la pratique au Centre de Proton Thérapie de l'Institut Paul Scherrer à Villigen : travail de Bachelor

BUT : La présente étude cherche à connaître l’activité des techniciens en radiologie médicale en protonthérapie et à mettre en lumière ses différences par rapport à la radiothérapie conventionnelle. La radiothérapie représente un domaine d’activité important pour le TRM. Son rôle et ses responsabilités ont considérablement évolué au cours de ces dix dernières années. Exerçant un métier en constante mutation, le technicien devra, à l’avenir, s’adapter continuellement à la course aux radiothérapies innovantes, galvanisées par une croissance effrénée des avancées technologiques. La protonthérapie est la forme la plus sophistiquée de la radiothérapie. A ce titre, elle constitue une arme aboutie et précise pour traiter certains cancers. Cette technique de pointe demeure néanmoins peu répandue puisque, en Suisse, seul un centre en est équipé, à savoir Le Centre de Proton Thérapie de l’Institut Paul Scherrer. METHODOLOGIE : Pour décrire l’activité du TRM en protonthérapie et dresser un portrait comparatif par rapport à la radiothérapie photonique, plusieurs méthodes qualitatives de recueil de données ont été retenues. L’observation directe et les entretiens semi-directifs ont été jugés probants. Les entretiens, en particulier, permettent, par l’interrogation du sujet, de se centrer sur son discours. L’observation directe, elle, en plus d’être conduite sur le terrain où se déroulent les activités étudiées, autorise un accès instantané aux actions telles qu’effectivement réalisées ainsi qu’aux gestes professionnels tels que concrètement effectués. RESULTATS : Au vu des éléments recueillis et analysés, l’activité du TRM en protonthérapie semble être relativement identique à celle pratiquée en radiothérapie traditionnelle. Ceci dit, par l’intermédiaire de nos questionnements, de nos entretiens et de nos observations, il a tout de même été possible d’établir un inventaire composé d’une multitude de détails et de nuances rendant compte des spécificités et des particularités de cette activité. CONCLUSION : Actuellement, les thérapies modernes traitant le cancer englobent plusieurs méthodes de traitement, dont la plus répandue est la chirurgie suivie de l’irradiation. Fors l’aspect purement physique, il s’est révélé particulièrement instructif et opportun de documenter ce domaine ultraspécialisé de l’irradiation des tumeurs, dans la mesure où aucune étude n’avait, jusqu’à ce jour, étudié la place centrale occupée par le TRM au sein de ce processus thérapeutique

Clostridium perfringens epsilon toxin induces blood brain barrier permeability via caveolae-dependent transcytosis and requires expression of MAL.

Clostridium perfringens epsilon toxin (ETX) is responsible for causing the economically devastating disease, enterotoxaemia, in livestock. It is well accepted that ETX causes blood brain barrier (BBB) permeability, however the mechanisms involved in this process are not well understood. Using in vivo and in vitro methods, we determined that ETX causes BBB permeability in mice by increasing caveolae-dependent transcytosis in brain endothelial cells. When mice are intravenously injected with ETX, robust ETX binding is observed in the microvasculature of the central nervous system (CNS) with limited to no binding observed in the vasculature of peripheral organs, indicating that ETX specifically targets CNS endothelial cells. ETX binding to CNS microvasculature is dependent on MAL expression, as ETX binding to CNS microvasculature of MAL-deficient mice was not detected. ETX treatment also induces extravasation of molecular tracers including 376Da fluorescein salt, 60kDA serum albumin, 70kDa dextran, and 155kDA IgG. Importantly, ETX-induced BBB permeability requires expression of both MAL and caveolin-1, as mice deficient in MAL or caveolin-1 did not exhibit ETX-induced BBB permeability. Examination of primary murine brain endothelial cells revealed an increase in caveolae in ETX-treated cells, resulting in dynamin and lipid raft-dependent vacuolation without cell death. ETX-treatment also results in a rapid loss of EEA1 positive early endosomes and accumulation of large, RAB7-positive late endosomes and multivesicular bodies. Based on these results, we hypothesize that ETX binds to MAL on the apical surface of brain endothelial cells, causing recruitment of caveolin-1, triggering caveolae formation and internalization. Internalized caveolae fuse with early endosomes which traffic to late endosomes and multivesicular bodies. We believe that these multivesicular bodies fuse basally, releasing their contents into the brain parenchyma

Morphological and Biochemical Characterization of the Cornified Envelopes from Human Epidermal Keratinocytes of Different Origin

The formation of a cornified envelope (CE) is a major event in the terminal differentiation of epidermal cells. Nomarski contrast microscopy of the envelopes purified from different sources reveals the existence of two major, but morphologically distinct classes: the very irregularily shaped fragile type CEf. Psoriatic scales from different patients show both types in varying proportions. Tape stripping of normal epidermis reveals that type CEf is present in the lowermost layers of the stratum conreum and type CEr is present in the upper layers, indicating that the two types represent a different stage of maturation. Cyanogen bromide peptide mapping of electrophoretically purified envelopes reveals striking differences between cultured keratinocytes, normal epidermis, and psoriatic scales but also slight interindividual variations. This variability supports the view that the molecular CE composition is not strictly determined. On the other hand, no difference could be detected in the peptide maps of CEf and CEr obtained after tape stripping from the same healthy volunteer indicating that CE maturation within the stratum corneum does not involve the provision of qualitatively new proteins

A Discrete Choquet Integral for Ordered Systems

A model for a Choquet integral for arbitrary finite set systems is presented. The model includes in particular the classical model on the system of all subsets of a finite set. The general model associates canonical non-negative and positively homogeneous superadditive functionals with generalized belief functions relative to an ordered system, which are then extended to arbitrary valuations on the set system. It is shown that the general Choquet integral can be computed by a simple Monge-type algorithm for so-called intersection systems, which include as a special case weakly union-closed families. Generalizing Lov\'asz' classical characterization, we give a characterization of the superadditivity of the Choquet integral relative to a capacity on a union-closed system in terms of an appropriate model of supermodularity of such capacities