Experiments shed new light on nickel-fluorine reactions

Isotopic tracer experiments and scale-impingement experiments show fluorine to be the migrating species through the nickel fluoride scale formed during the fluorination of nickel. This is in contrast to nickel oxide scales, where nickel is the migrating species

Les phénomènes de dépendance à l’environnement: réflexions sur l’autonomie humaine à partir de la clinique neurologique

Dans cet article, nous proposons d’analyser la perte d’autonomie caractérisée par les phénomènes de dépendance à l’environnement observés chez certains patients neurologiques présentant des lésions des lobes frontaux. Des propositions théoriques issues de la neuropsychologie cognitive et de la théorie de la médiation sont développées et confrontées. La démarche offre l’occasion, au plan théorique, de questionner la détérioration possible du système de la personne suite à des lésions cérébrales et, au plan méthodologique, d’interroger notre manière d’examiner ces patients en confrontant les modèles théoriques aux observations clinique

Fast Monte Carlo Simulation for Patient-specific CT/CBCT Imaging Dose Calculation

Recently, X-ray imaging dose from computed tomography (CT) or cone beam CT (CBCT) scans has become a serious concern. Patient-specific imaging dose calculation has been proposed for the purpose of dose management. While Monte Carlo (MC) dose calculation can be quite accurate for this purpose, it suffers from low computational efficiency. In response to this problem, we have successfully developed a MC dose calculation package, gCTD, on GPU architecture under the NVIDIA CUDA platform for fast and accurate estimation of the x-ray imaging dose received by a patient during a CT or CBCT scan. Techniques have been developed particularly for the GPU architecture to achieve high computational efficiency. Dose calculations using CBCT scanning geometry in a homogeneous water phantom and a heterogeneous Zubal head phantom have shown good agreement between gCTD and EGSnrc, indicating the accuracy of our code. In terms of improved efficiency, it is found that gCTD attains a speed-up of ~400 times in the homogeneous water phantom and ~76.6 times in the Zubal phantom compared to EGSnrc. As for absolute computation time, imaging dose calculation for the Zubal phantom can be accomplished in ~17 sec with the average relative standard deviation of 0.4%. Though our gCTD code has been developed and tested in the context of CBCT scans, with simple modification of geometry it can be used for assessing imaging dose in CT scans as well.Comment: 18 pages, 7 figures, and 1 tabl

Apraxia and Alzheimer’s Disease: Review and Perspectives

Apraxia is one of the cognitive deficits that characterizes Alzheimer\u27s disease. Despite its prevalence and relevance to diagnosing Alzheimer\u27s disease, this topic has received little attention and is without comprehensive review. The review herein is aimed to fill this gap by first presenting an overview of the impairment caused in different clinical situations: pantomime of tool use, single tool use, real tool use, mechanical problem solving, function and manipulation knowledge tasks, and symbolic/meaningless gestures. On the basis of these results, we then propose alternative interpretations regarding the nature of the underlying mechanisms impaired by the disease. Also presented are principal methodological issues precluding firm conclusions from being drawn

Building capabilities in disabled job seekers: A qualitative study of the Remploy Work Choices programme in Scotland

This article reports on a qualitative study of the UK’s labour activation pathway for jobseekers with disabilities and health conditions. The aim was to explore the experiences of Work Choices programme participants, specifically to identify barriers to employment, the resources available to them, and the kind of support experiences they found empowering. Nine adult jobseekers took part in research interviews. Accounts of their experience of the programme were recorded, transcribed, and analysed with Interpretative Phenomenological Analysis. The Capability Approach of Amartya Sen was used as the conceptual lens through which the data was interpreted. Participants reported substantive health conditions, lack of skills and confidence, and practical obstacles to finding work. They valued being treated with dignity, having genuine choice about their work and learning options, and experiencing a service underpinned by a supportive helping relationship

Development of an Hexapod BioMicroRobot with Nafion-Pt IPMC microlegs

This paper presents an artificial locomotion servo-system for an insect like hexapod BioMicroRobot (BMR). This servo-system, programmed with VHDL code, will act as a driver in a RISC architecture microcontroller to reproduce insect tripod walking. An overview of the robot control system, in accordance with the insect displacement principle, is demonstrated with timing parameters. A control algorithm of the six legs driving the robot in any direction versus Pulse Width Modulation (PWM) is reviewed. BMR microlegs are built with cylindrical Nafion-Pt Ionomeric Polymer-Metal Composite (IPMC) that have 2.5 degrees of freedom. Specific fabrication process for one leg is exposed. Dynamic behavior and microleg characteristics have been measured in deionized water using a laser vibrometer. BMR current consumption is an important parameter evaluated for each leg. Hardware test bench to acquired measurement is presented. The purpose of this design is to control a BMR for biomedical goals like implantation in human body. Experimental results on the proposed legs are conclusive for this type of bioinspired BMR

Conception d'un BioMicroRobot autonome

Cet article présente les avancements technologiques pour la conception théorique et pratique d'une architecture élémentaire et minimale d'un BioMicroRobot (BMR) hexapode autonome. L'autonomie minimale dépend du système de gestion des événements globaux, régionaux et locaux. Cette gestion est avant tout perçue par deux types de récepteurs : les extérocepteurs internes (vision) et ceux externes (système de repérage et de détection de l'environnement). La planification des événements dans un environnement confiné repose sur un système complexe qui incorpore un microcontrôleur d'architecture RISC, un système de propulsion bio-inspiré indépendant qui agit comme un pilote, un système d'alimentation et de communication et finalement un détecteur de proximité qui agit à titre d'extérocepteurs internes. L'avant dernière section présente un procédé de fabrication de la structure complète du BMR qui peut supporter une hiérarchie hybride à deux niveaux avec la logique floue

Spin dependence of the masses of heavy baryons

It is argued from the systematics of spin-depen\-dent forces between quarks that two proposed baryon states, named $\Sigma_c(2380)$ and $\Sigma_b(5760)$, do not exist.Comment: 6 pages, plainte