L'altération de la production du collagène de type I dans les ostéoblastes arthrosiques humains : implication dans le processus de minéralisation

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Con experiencia, pero frágiles : la complejidad del trabajo real que enfrentan los auxiliares de enfermería en geriatría en Quebec

Os auxiliares de enfermagem são responsáveis pelos cuidados prestados aos residentes em instituições geriátricas. Os auxiliares experientes têm duas características. Por um lado, aplicam o saber-fazer informal e indispensável para atingir os objetivos prescritos. Ao mesmo tempo, constituem uma categoria de emprego muito fragilizada, nomeadamente no que respeita à saúde no no trabalho. O objetivo do nosso artigo é apresentar o ponto de vista dos auxiliares sobre os fatores relacionados com a organização do trabalho que estão na origem desta fragilidade. Realizámos uma investigação qualitativa que consistiu em entrevistas com vinte auxiliares experientes com mais de dez anos de experiência em quatro centros de cuidados e alojamento de longa duração (Centres de Hébergement et de Soins de Longue Durée - CHSLD) no Quebeque (Canadá). Os três principais fatores identificados pelos auxiliares foram : o aumento da carga de trabalho que causa dificuldades na realização do trabalho prescrito ; a atividade de trabalho torna-se mais complexa ; e a distância dos superiores hierárquicos diretos que impede a realização de discussões coletivas sobre a qualidade das atividades.Los auxiliares de enfermería son responsables de las labores de asistencia dirigidas a los residentes en las instituciones geriátricas. Los auxiliares con experiencia presentan dos características. Por un lado, implementan el saber-hacer informal e indispensable para lograr los objetivos prescritos. Paralelamente, conforman una categoría de empleo muy debilitada, particularmente en términos de salud laboral. El objetivo de nuestro artículo es presentar el punto de vista de los auxiliares sobre los factores relativos a la organización del trabajo que provocan esta debilidad. Llevamos adelante una investigación cualitativa que consistió en entrevistas con veinte auxiliares experimentados, los cuales contaban con más de diez años de experiencia en cuatro Centres d’Hébergement et de Soins de Longue Durée (CHSLD) – Centros de alojamiento y de cuidados de larga duración - en Quebec (Canadá). Se documentaron los tres principales factores identificados por los auxiliares : el aumento de la carga laboral que provoca una dificultad para realizar el trabajo prescrito ; la actividad laboral se complejiza ; y el distanciamiento con el superior inmediato que impide las discusiones colectivas acerca de la calidad de las actividades.Les préposés aux bénéficiaires sont responsables de l’ensemble des activités d’assistance envers les résidents dans les organisations gériatriques. Les préposés expérimentés présentent deux caractéristiques. D’une part, elles mettent en œuvre des savoir-faire informels indispensables pour l’atteinte des objectifs prescrits. Parallèlement, elles composent une catégorie d’emploi très fragilisée, notamment en termes de santé au travail. L’objectif de notre article est de présenter le point de vue des préposés sur les facteurs relatifs à l’organisation du travail qui provoquent cette fragilité. Nous avons réalisé une recherche qualitative se composant d’entrevues avec vingt préposés expérimentés détenant plus de dix ans d’ancienneté et travaillant dans quatre Centres d’Hébergement et de Soins de Longue Durée (CHSLD) du Québec. Trois principaux facteurs identifiés par les préposés sont documentés : L’intensification de la charge de travail provoque une difficulté à réaliser le travail prescrit ; l’activité de travail se complexifie ; et l’éloignement du gestionnaire immédiat empêche les discussions collectives sur la qualité des activités.Personal care workers (PCW) are responsible for all nursing assistance activities for residents in geriatric organizations. The experienced PCW have two characteristics. On the one hand, they use informal know-how that are essential for achieving the prescribed objectives. At the same time, they constitute a very fragile job category, particularly in terms of occupational health. The objective of our paper is to present the point of view of these workers on the factors relating to the organization of work which cause this fragility. We carried out qualitative research consisting of interviews with twenty experienced PCW with more than ten years of experience, working in four Long-Term Care Centers (CHSLDs) in Quebec (Canada). The three main factors identified by the professionals are : The intensification of the workload causes difficulty in carrying out the prescribed work ; the work activity becomes more complex ; and the distance of the immediate manager prevents collective discussions on the quality of the activities

SRSC: SDN-based Routing Scheme for CCN

International audienceContent delivery such as P2P or video streaming generates the main part of the Internet traffic and Content Centric Network (CCN) appears as an appropriate architecture to satisfy the user needs. However, the lack of scalable routing scheme is one of the main obstacles that slows down a large deployment of CCN at an Internet-scale. In this paper we propose to use the Software-Defined Networking (SDN) paradigm to decouple data plane and control plane and present SRSC, a new routing scheme for CCN. Our solution is a clean-slate approach using only CCN messages and the SDN paradigm. We implemented our solution into the NS-3 simulator and perform simulations of our proposal. SRSC shows better performances than the flooding scheme used by default in CCN: it reduces the number of messages, while still improves CCN caching performances

Green Growth in NDN: Deployment of Content Stores

International audienceNamed-Data Networking architecture relies on cache networks, where nodes store the data for further requests. However, the memory needed at each node called Content Store represents the most significant part of the entire cost of the infrastructure that has to be supported by network providers, making difficult the change from the current Internet infrastructure to a Future Internet based on NDN. Thus, a legitimate question would be: "are all these Content Stores useful in a large-scale NDN network?" In this paper, we investigate theimpact of Content Stores in NDN network, and we evaluate the performances of the NDN architecture according to the number of Content Stores effectively deployed in the network. We show through extensive simulation experiments in NS-3 that only about 50% of nodes with Content Stores is enough to achieve higher level of performances than a fully-deployed NDN network. This result is very important for the deployment of NDN architecture as it shows that the infrastructure cost can be drastically reduced and it is an incentive for network providers that benefits directly from this result

Implementation and Evaluation of a Controller-Based Forwarding Scheme for NDN

International audienceNamed-Data Networking (NDN) is a novel clean-slate architecture for Future Internet. It has been designed to take into account a new use of the Internet and especially accessing content for a large number of users, and it integrates several features such as in-network caching, security or multipath. As NDN relies on content names instead of host address, it cannot rely on traditional Internet routing, and it is therefore essential to propose a routing scheme adapted for NDN. To this end, in this paper, we present SRSC, our SDN-based Routing Scheme for CCN/NDN and its implementation. SRSC relies on the SDN paradigm.A controller is responsible to forward decisions and to set up rules into NDN nodes. We implement SRSC into NDNx and we also deploy an NDN testbed within a virtual environment and real ISP topology in order to evaluate the performances of our proposal with real-world experiments. We demonstrate the feasibility of SRSC and its ability to forward Interest messages in a fully deployed NDN environment, while keeping low overhead and computation time and high caching performances

Croissance Verte dans NDN: Déploiement des Content Stores

International audienceL'architecture Named-Data Networking (NDN) consiste en un réseau de caches, o` u les noeuds peuvent stocker les données qui transitent pour satisfaire les futures requêtes. La mémoire requisè a chaque noeud, appelée Content Store, représente ainsi la majeure partie du coût de l'infrastructure. Cet article se propose d'´ etudier s'il est utile que tous les noeuds soient equipés de Content Stores pour améliorer les performances de l'architecture NDN. Pour cela, nous etudions l'impact du nombre de Content Stores dans un réseau NDN et evaluons ses performances. Nous montrons a travers d'importantes expériences de simulations avec NS-3 et son module ndnSIM que les performances de NDN sont optimales avec seulement 50% de noeuds equipés de Content Stores. C'est un résultat important pour les opérateurs réseaux car cela montre que l'architecture NDN peut etre déployéè a un coût d'infrastructure réduit

Abnormal insulin-like growth factor 1 signaling in human osteoarthritic subchondral bone osteoblasts

Insulin-like growth factor (IGF)-1 is a key factor in bone homeostasis and could be involved in bone tissue sclerosis as observed in osteoarthritis (OA). Here, we compare the key signaling pathways triggered in response to IGF-1 stimulation between normal and OA osteoblasts (Obs). Primary Obs were prepared from the subchondral bone of tibial plateaus of OA patients undergoing knee replacement or from normal individuals at autopsy. Phenotypic characterization of Obs was evaluated with alkaline phosphatase and osteocalcin release. The effect of IGF-1 on cell proliferation, alkaline phosphatase and collagen synthesis was evaluated in the presence or not of 50 ng/ml IGF-1, whereas signaling was studied with proteins separated by SDS-PAGE before western blot analysis. We also used immunoprecipitation followed by western blot analysis to detect interactions between key IGF-1 signaling elements. IGF-1 receptor (IGF-1R), Shc, Grb2, insulin receptor substrate (IRS)-1, and p42/44 mitogen-activated protein kinase (MAPK) levels were similar in normal and OA Obs in the presence or absence of IGF-1. After IGF-1 stimulation, the phosphorylation of IGF-1R in normal and OA Obs was similar; however, the phosphorylation of IRS-1 was reduced in OA Ob. In addition, the PI3K pathway was activated similarly in normal and OA Obs while that for p42/44 MAPK was higher in OA Obs compared to normal. p42/44 MAPK can be triggered via an IRS-1/Syp or Grb2/Shc interaction. Interestingly, Syp was poorly phosphorylated under basal conditions in normal Obs and was rapidly phosphorylated upon IGF-1 stimulation, yet Syp showed a poor interaction with IRS-1. In contrast, Syp was highly phosphorylated in OA Obs and its interaction with IRS-1 was very strong initially, yet rapidly dropped with IGF-1 treatments. The interaction of Grb2 with IRS-1 progressively increased in response to IGF-1 in OA Obs whereas this was absent in normal Ob. IGF-1 stimulation altered alkaline phosphatase in Ob, an effect reduced in the presence of PD98059, an inhibitor of p42/44 MAPK signaling, whereas neither IGF-1 nor PD98059 had any significant effect on collagen synthesis. In contrast, cell proliferation was higher in OA Obs compared to normal under basal conditions, and IGF-1 stimulated more cell proliferation in OA Obs than in normal Ob, an effect totally dependent on p42/44 MAPK activiy. The altered response of OA Obs to IGF-1 may be due to abnormal IGF-1 signaling in these cells. This is mostly linked with abnormal IRS-1/Syp and IRS-1/Grb2 interaction in these cells

Circadian oscillations of cytosolic free calcium regulate the Arabidopsis circadian clock

In the last decade, the view of circadian oscillators has expanded from transcriptional feedback to incorporate post-transcriptional, post-translational, metabolic processes and ionic signalling. In plants and animals, there are circadian oscillations in the concentration of cytosolic-free Ca2+ ([Ca2+]cyt), though their purpose has not been fully characterised. We investigated whether circadian oscillations of [Ca2+] cyt regulate the circadian oscillator of Arabidopsis thaliana. We report that in Arabidopsis, [Ca2+]cyt circadian oscillations can regulate circadian clock function through the Ca2+-dependent action of CALMODULIN-LIKE24 (CML24). Genetic analyses demonstrate a linkage between CML24 and the circadian oscillator, through pathways involving the circadian oscillator gene TIMING OF CAB2 EXPRESSION1 (TOC1).Supported by BBSRC UK research grants BBSRC BB/D010381/1 (A.N.D.), BB/D017904/1 (F.R.) BB/M00113X/1 (H.J.H.) awarded to (A.A.R.W.), Research Studentship (K.H.) and BBSRC Industrial Case (T.H.). A Swiss Science Foundation Award (PBZHP3-123289) and the Isaac Newton Trust Cambridge (M.C.M.R. and S.A.), 678 the National Science Foundation under Grant No. MCB 0817976 (Y-C.T. and J.B.), a Royal Society Grant RG081257 and Corpus Christi College, Cambridge Junior Research Fellowship (M.J.G.), a Cordenadoria de Apoio ao Ensino Superior Brazil 25681 studentship (C.T.H.), IEF Marrie Curie (Project No. 272186) (M.C.M.R.), a Broodbank Fellowship (M.C.M.R.), a Malaysian Government Studentship (N.I.M-H.)

The Swiss Approach - feasibility of a national low-dose CT lung cancer screening program.

BACKGROUND Lung cancer is the leading cause of cancer-related deaths in Switzerland. Despite this, there is no lung cancer screening program in the country. In the United States, low-dose computed tomography (LDCT) lung cancer screening is partially established and endorsed by guidelines. Moreover, evidence is growing that screening reduces lung cancer-related mortality and this was recently shown in a large European randomized controlled trial. Implementation of a lung cancer screening program, however, is challenging and depends on many country-specific factors. The goal of this article is to outline a potential Swiss lung cancer screening program. FRAMEWORK An exhaustive literature review on international screening models as well as interviews and site visits with international experts were initiated. Furthermore, workshops and interviews with national experts and stakeholders were conducted to share experiences and to establish the basis for a national Swiss lung cancer screening program. SCREENING APPROACH General practitioners, pulmonologists and the media should be part of the recruitment process. Decentralisation of the screening might lead to a higher adherence rate. To reduce stigmatisation, the screening should be integrated in a "lung health check". Standardisation and a common quality level are mandatory. The PLCOm2012 risk calculation model with a threshold of 1.5% risk for developing cancer in the next six years should be used in addition to established inclusion criteria. Biennial screening is preferred. LUNG RADS and NELSON+ are applied as classification models for lung nodules. CONCLUSION Based on data from recent studies, literature research, a health technology assessment, the information gained from this project and a pilot study the Swiss Interest Group for lung cancer screening (CH-LSIG) recommends the timely introduction of a systematic lung cancer screening program in Switzerland. The final decision is for the Swiss Cancer Screening Committee to make