Environnement et santé : une approche géographique du paludisme au Mondolkiri (Cambodge)

Le paludisme est un enjeu de santé publique majeur au Cambodge. La très forte mobilité des populations, la libre circulation de nombreux traitements médicamenteux sur le marché local et les pressions sur les zones forestières au Nord et à l’Ouest du pays pour la coupe de bois précieux viennent intensifier les échanges entre l’être humain et le vecteur du Plasmoduim responsable de la maladie. Ces phénomènes à l’intensité croissante font planer un risque quant à la transmission des chimiorésistances du parasite aux traitements ACT. Il est nécessaire d’analyser finement les dynamiques de transmission de la maladie pour mener des interventions ciblées sur les facteurs de risque et de vulnérabilités des populations. L’étude propose une approche géographique pour analyser les déterminants de variabilité de la prévalence du paludisme dans la région du Mondolkiri, Cambodge. Les déterminants de risque de transmission à l’échelle collective du village, sont comparés statistiquement aux données sanitaires recueillies auprès des Centres de Santé et des Village Malaria Workers (VMW). Une enquête dans 130 foyers de 4 villages aux facies socio-environnementaux et épidémiologiques différenciés a été menée pour déterminer les facteurs de risque à l’échelle individuelle. Les variables démographiques, socio-économiques, de pratiques et de connaissances sur la maladie seront comparées aux indices de morbidité au sein du foyer pour une année. L’étude montre l’importance de certains facteurs de risque sur la morbidité et notamment a) La pratique d’une activité en forêt, b) La pratique de la culture sur brulis c) la qualité du bâti du foyer d) l’usage de moustiquaire. D’autre part, nos résultats montrent l’importance du dispositif de vigilance communautaire VMW pour le diagnostic et le traitement du paludisme, comme le risque de sous-diagnostic important de la maladie pour les villages sans accès aux soins. L’étude offre des pistes de réflexions pour de futures interventions de santé publique. D’autre part, les résultats démontrent une nouvelle fois les inégalités qui touchent les populations sur leurs connaissances liées aux traitements du paludisme et à sa prévention, malgré un investissement important des pouvoirs publics et de diverses associations au niveau local.Malaria is a major public health challenge in Cambodia. Interaction between human beings and the Plasmoduim vector is intensified due to strong population movement, free distribution of numerous medical treatments in local markets and the recent exploitation of valuable timber from the northern and western forest zones of the country. These intense and increasing phenomena implies a risk for the diffusion of parasites quimioresistance in ACT treatments. It is necessary to finely analyse transmission dynamics of the disease in order to design specific interventions that address risk factors and that are adapted to local context. This study proposes a geographic approach to analyse the determinants of malaria’s prevalence variability in the Mondolkiri region (Cambodia). Collective transmission determinants per village were compared with sanitary data collected in Health centres and Villages Malaria Workers (VMW) registry. Different socio-environmental and epidemiologic conditions of households in the four villages and 130 households were also examined to determine individual risk factors. Demographic, socioeconomic, practices and disease knowledge variables were compared with morbidity indexes for each household. Importance of certain morbidity risk factors was specified : a) forest activities practice, b) burning culture practices, c) construction quality of houses, d) use of mosquito net. Also, our results show the importance of community surveillance actions VMW to diagnose and treat malaria, so as the risk of underdiagnose in villages without access to healthcare. The study offers insight for future public health interventions. Particularly for the main population at risk : men between 16 and 25 years old that habitually practice forest activities. Furthermore, the results evidence ones more the inequities present in population’s knowledge of malaria treatments and prevention measures, in spite of the investment of public authorities and local associations

Fabrication of chitosan-flax composites with differing molecular weights and its effect on mechanical properties

An aqueous fabrication method is investigated for a composite reinforced with chitosan and flax fibers. The composite is characterized structurally, mechanically and chemically. A strong influence of molecular weight (MW) is identified on the composite properties. A strong fiber-matrix interface, which is associated with porosity and effective fiber impregnation, is achieved by applying low molecular weight (LMW) solution followed by casting using LMW or medium molecular weight (MMW) solution. Porosity is analyzed using μ-CT analysis. Increasing porosity with increasing molecular weight results in a decline of the tensile and flexural properties of the composites. The chitosan-flax composites have a low density compared to synthetic and natural fiber composites, which is a competitive advantage as a replacement material for particle board or plyboard in suspended ceilings, furniture compartments, sports or leisure equipment. A multiscale simulation is carried out to compute the directional effective elastic properties and predicts a potential 21% improvement of the tensile modulus if the process is optimized. This work shows the potential of chitosan-flax composites as a sustainable green material with an aqueous fabrication procedure and useful mechanical properties

SkiROS:A four tiered architecture for task-level programming of industrial mobile manipulators

During the last decades, the methods for intuitive task level programming of robots have become a fundamental point of interest for industrial application. The paper in hand presents SkiROS (Skill-based Robot Operating System) a novel software architecture based on the skills paradigm. The skill paradigm has already been used and tested within the FP7 project TAPAS, and we are going to use it in several new FP7 projects (CARLOS, STAMINA, ACAT). It facilitates task-level programming of mobile manipulators by providing the robot with a set of movement primitives, skills and tasks. This hierarchy brings many advantages, where the most relevant is the separation of control in the layers of hardware abstraction(proxy), multi-sensory control(primitive), object-level abstraction (skill) and planning (task). The definition and the clear division in different abstraction levels allows the implementation of a flexible, highly modular system for the development of cognitive robot tasks

Determination of radiation hardness of silicon diodes

In this paper, we describe an experiment aimed to measure the physical observables, which can be used for the assessment of the radiation hardness of commercially available silicon photo diodes commonly used as nuclear detectors in particle accelerator laboratories. The experiment adopted the methodology developed during the International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP No. F11016) “Utilization of Ion Accelerators for Studying and Modelling Ion Induced Radiation Defects in Semiconductors and Insulators”. This methodology is based on the selective irradiation of micrometer-sized regions with different fluences of MeV ions using an ion microbeam and on the measurement of the charge collection efficiency (CCE) degradation by Ion Beam Induced Charge (IBIC) microscopy performed in full depletion condition, using different probing ions. The IBIC results are analyzed through a theoretical approach based on the Shockley-Read-Hall model for the free carrier recombination in the presence of ion-induced deep traps. This interpretative model allows the evaluation of the material radiation hardness in terms of recombination parameters for both electrons and holes. The device under study in this experiment was a commercial p-i-n photodiode, which was initially characterized by i) standard electronic characterization techniques to determine its doping and ii) the Angle-Resolved IBIC to evaluate its effective entrance window. Nine regions of (100 × 100) µm2 were irradiated with 11.25 MeV He ions up to a maximum fluence of 3·1012 ions/cm2. The CCE degradation was measured by the IBIC technique using 11.25 MeV He and 1.4 MeV He as probing ions. The model presented here proved to be effective for fitting the experimental data. The fitting parameters correspond to the recombination coefficients, which are the key parameters for the characterization of the effects of radiation damage in semiconductors.</p

Differential effects of α4β7 and GPR15 on homing of effector and regulatory T cells from patients with UC to the inflamed gut in vivo

Objective: Gut homing of lymphocytes via adhesion molecules has recently emerged as new target for therapy in inflammatory bowel diseases. We aimed to analyze the in vivo homing of effector (Teff) and regulatory (Treg) T cells to the inflamed gut via α4β7 and GPR15. Design: We assessed the expression of homing receptors on T cells in peripheral blood and inflamed mucosa. We studied the migration pattern and homing of Teff and Treg cells to the inflamed gut using intravital confocal microscopy and FACS in a humanized mouse model in DSS-treated NSG (NOD.Cg-Prkdcscid-Il2rgtm1Wjl/SzJ) mice. Results: Expression of GPR15 and α4β7 was significantly increased on Treg rather than Teff cells in peripheral blood of patients with ulcerative colitis (UC) as compared to Crohn´s disease and controls. In vivo analysis in a humanized mouse model showed augmented gut homing of UC Treg cells as compared to controls. Moreover, suppression of UC (but not control) Teff and Treg cell homing was noted upon treatment with the α4β7 antibody vedolizumab. In contrast, siRNA blockade of GPR15 had only effects on homing of Teff cells but did not affect Treg homing in UC. Clinical vedolizumab treatment was associated with marked expansion of UC Treg cells in peripheral blood. Conclusion: α4β7 rather than GPR15 is crucial for increased colonic homing of UC Treg cells in vivo, while both receptors control UC Teff homing. Vedolizumab treatment impairs homing of UC Treg cells leading to their accumulation in peripheral blood with subsequent suppression of systemic effector T cell expansion