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Search Results: 1 - 10 of 35837 matches for " Jean Le Fur "
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Extending Life Concepts to Complex Systems
Jean Le Fur
Interdisciplinary Description of Complex Systems , 2013,
Abstract: There is still no consensus definition of complex systems. This article explores, as a heuristic approach, the possibility of using notions associated with life as transversal concepts for defining complex systems. This approach is developed within a general classification of systems, with complex systems considered as a general ‘living things’ category and living organisms as a specialised class within this category. Concepts associated with life are first explored in the context of complex systems: birth, death and lifetime, adaptation, ontogeny and growth, reproduction. Thereafter, a refutation approach is used to test the proposed classification against a set of diverse systems, including a reference case, edge cases and immaterial complex systems. The summary of this analysis is then used to generate a definition of complex systems, based on the proposal, and within the background of cybernetics, complex adaptive systems and biology. Using notions such as ‘birth’ or ‘lifespan’ as transversal concepts may be of heuristic value for the generic characterization of complex systems, opening up new lines of research for improving their definition.
Ammonium diphosphitoindate(III)
Farida Hamchaoui,Houria Rebbah,Eric Le Fur
Acta Crystallographica Section E , 2013, DOI: 10.1107/s160053681300771x
Abstract: The crystal structure of the title compound, NH4[In(HPO3)2], is built up from InIII cations (site symmetry 3m.) adopting an octahedral environment and two different phosphite anions (each with site symmetry 3m.) exhibiting a triangular–pyramidal geometry. Each InO6 octahedron shares its six apices with hydrogen phosphite groups. Reciprocally, each HPO3 group shares all its O atoms with three different metal cations, leading to [In(HPO3)2] layers which propagate in the ab plane. The ammonium cation likewise has site symmetry 3m.. In the structure, the cations are located between the [In(HPO3)2] layers of the host framework. The sheets are held together by hydrogen bonds formed between the NH4+ cations and the O atoms of the framework.
Improving Municipal Solid Waste Land Filling Disposal Process: Experiments with a Laboratory Scale Rotary Kiln  [PDF]
Jean Fidèle Nzihou
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.48087
Abstract:

Developing countries often face the challenge of managing continuously growing quantity of municipal waste. Waste is often disposed of by stockpiling and land filling because these have been found the cheapest waste disposal methods in the world. Unfortunately, these waste disposal methods are often source of visual pollution, water contamination and greenhouse effect gas emissions. Waste disposal by incineration has been found effective and now is one of the mostly used waste disposal method in several developed countries. Nevertheless, setting up appropriate waste incinerator requires a good of the combustion process. Unfortunately, direct studies on industrial facilities are not easily feasible because of technical issues and financial limitations. Studies and throughout testing frequently need to be carried out at laboratory scale. Work herein reported first overviewed operation conditions of the landfill facility in the town of Ouagadougou. In the second time for incineration simulation, batch experiments are carried out with a rotary kiln furnace to study the effects of the residence time on emissions of NO, NO2, CO, CO2 and SO2 in the atmosphere. For each rotation speed, emissions of NO, NO2, CO, CO2 and SO2 from the incineration of a household combustible fraction model waste consisting of wood (53%), cardboard (25%) and plastics (22%) have been recorded. The lifespan of the land filling facility with incineration has been estimated. Our work show that it may be improved up to roughly three times that of simple land filling. Visual pollution maybe drastically reduced and atmospheric pollution reduced

Deletion of TRAAK Potassium Channel Affects Brain Metabolism and Protects against Ischemia
Christophe Laigle, Sylviane Confort-Gouny, Yann Le Fur, Patrick J. Cozzone, Angèle Viola
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0053266
Abstract: Cerebral stroke is a worldwide leading cause of disability. The two-pore domain K+ channels identified as background channels are involved in many functions in brain under physiological and pathological conditions. We addressed the hypothesis that TRAAK, a mechano-gated and lipid-sensitive two-pore domain K+ channel, is involved in the pathophysiology of brain ischemia. We studied the effects of TRAAK deletion on brain morphology and metabolism under physiological conditions, and during temporary focal cerebral ischemia in Traak?/? mice using a combination of in vivo magnetic resonance imaging (MRI) techniques and multinuclear magnetic resonance spectroscopy (MRS) methods. We provide the first in vivo evidence establishing a link between TRAAK and neurometabolism. Under physiological conditions, Traak?/? mice showed a particular metabolic phenotype characterized by higher levels of taurine and myo-inositol than Traak+/+ mice. Upon ischemia, Traak?/? mice had a smaller infarcted volume, with lower contribution of cellular edema than Traak+/+ mice. Moreover, brain microcirculation was less damaged, and brain metabolism and pH were preserved. Our results show that expression of TRAAK strongly influences tissue levels of organic osmolytes. Traak?/? mice resilience to cellular edema under ischemia appears related to their physiologically high levels of myo-inositol and of taurine, an aminoacid involved in the modulation of mitochondrial activity and cell death. The beneficial effects of TRAAK deletion designate this channel as a promising pharmacological target for the treatment against stroke.
Review of current health care in the general psychiatry sectors and of access to general medicine
Coldefy M,Le Fur Ph,Lucas-Gabrielli V,Mousquès J
Pratiques et Organisation des Soins , 2009,
Abstract: Fifty years after the 1960 circular, it must be observed that, although the psychiatric sector presents a common organisational or functional framework, the reality of organisational practices and disparity of both the commitment to community psychiatry and of the human, material and financial resources available in the sectorsmean that there are considerable gaps in the latter.This study seeks to report these disparities between adult psychiatry sectors and to analyse their impact on patient access to health care from GPs and private psychiatrists.We first drew up a typology of adult psychiatry sectors, based on data from the sector activity reports as well as on environmental data concerning the health care and social services available and the population covered. This can be used to rank the sectors according to their score and level of commitment to the objectives of sectordivision.We then analysed the links between these disparities and the level of access to health care from private psychiatrists and GPs on an experimental basis in the Parisian region. We revealed a phenomenon of substitution, in those psychiatry sectors that could be consideredto be under or not as well equipped as the median, between public psychiatry and treatment by GPs. We also found more frequent use of antipsychotics associated with this substitution, which could indicate the treatment of serious diseases that are usually followedup in the sectors.Prat Organ Soins 2009;40(3):197-206
Interaction between peroxisomes and mitochondria in fatty acid metabolism  [PDF]
Fran?oise Le Borgne, Jean Demarquoy
Open Journal of Molecular and Integrative Physiology (OJMIP) , 2012, DOI: 10.4236/ojmip.2012.21005
Abstract: Peroxisomes and mitochondria are ubiquitously found organelles. They both are dynamic structures able to divide, to fuse and to undergo autophagic processes. Their activities are dependent on proteins that are, for most (mitochondria) or all (peroxisome) of them, synthesized in the cytosol from the nuclear genome. Nevertheless, the membrane structures and the DNA content differ between these two organelles. Mitochondria possess a small circular genome while peroxisomes don’t. The control of their dynamic is dependent on specific factors even if some of those are able to affect both. These two organelles are metabolically connected: they are both involved in lipid metabolism. They are both able to beta oxidize fatty acids and are implicated in ROS production. However, their precise function in these metabolic pathways and their physiological functions are different. While mitochondrial metabolism is closely related to energy production, peroxisome does not seem to be associated with energy production but with the production of bioactive molecules and in detoxification processes.
Multimodal MRI and 31P-MRS Investigations of the ACTA1(Asp286Gly) Mouse Model of Nemaline Myopathy Provide Evidence of Impaired In Vivo Muscle Function, Altered Muscle Structure and Disturbed Energy Metabolism
Charlotte Gineste, Guillaume Duhamel, Yann Le Fur, Christophe Vilmen, Patrick J. Cozzone, Kristen J. Nowak, David Bendahan, Julien Gondin
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0072294
Abstract: Nemaline myopathy (NM), the most common non-dystrophic congenital disease of skeletal muscle, can be caused by mutations in the skeletal muscle α-actin gene (ACTA1) (~25% of all NM cases and up to 50% of severe forms of NM). Muscle function of the recently generated transgenic mouse model carrying the human Asp286Gly mutation in the ACTA1 gene (Tg(ACTA1)Asp286Gly) has been mainly investigated in vitro. Therefore, we aimed at providing a comprehensive picture of the in vivo hindlimb muscle function of Tg(ACTA1)Asp286Gly mice by combining strictly noninvasive investigations. Skeletal muscle anatomy (hindlimb muscles, intramuscular fat volumes) and microstructure were studied using multimodal magnetic resonance imaging (Dixon, T2, Diffusion Tensor Imaging [DTI]). Energy metabolism was studied using 31-phosphorus Magnetic Resonance Spectroscopy (31P-MRS). Skeletal muscle contractile performance was investigated while applying a force-frequency protocol (1–150 Hz) and a fatigue protocol (6 min–1.7 Hz). Tg(ACTA1)Asp286Gly mice showed a mild muscle weakness as illustrated by the reduction of both absolute (30%) and specific (15%) maximal force production. Dixon MRI did not show discernable fatty infiltration in Tg(ACTA1)Asp286Gly mice indicating that this mouse model does not reproduce human MRI findings. Increased T2 values were observed in Tg(ACTA1)Asp286Gly mice and might reflect the occurrence of muscle degeneration/regeneration process. Interestingly, T2 values were linearly related to muscle weakness. DTI experiments indicated lower λ2 and λ3 values in Tg(ACTA1)Asp286Gly mice, which might be associated to muscle atrophy and/or the presence of histological anomalies. Finally 31P-MRS investigations illustrated an increased anaerobic energy cost of contraction in Tg(ACTA1)Asp286Gly mice, which might be ascribed to contractile and non-contractile processes. Overall, we provide a unique set of information about the anatomic, metabolic and functional consequences of the Asp286Gly mutation that might be considered as relevant biomarkers for monitoring the severity and/or the progression of NM and for assessing the efficacy of potential therapeutic interventions.
Combined MRI and 31P-MRS Investigations of the ACTA1(H40Y) Mouse Model of Nemaline Myopathy Show Impaired Muscle Function and Altered Energy Metabolism
Charlotte Gineste, Yann Le Fur, Christophe Vilmen, Arnaud Le Troter, Emilie Pecchi, Patrick J. Cozzone, Edna C. Hardeman, David Bendahan, Julien Gondin
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061517
Abstract: Nemaline myopathy (NM) is the most common disease entity among non-dystrophic skeletal muscle congenital diseases. Mutations in the skeletal muscle α-actin gene (ACTA1) account for ~25% of all NM cases and are the most frequent cause of severe forms of NM. So far, the mechanisms underlying muscle weakness in NM patients remain unclear. Additionally, recent Magnetic Resonance Imaging (MRI) studies reported a progressive fatty infiltration of skeletal muscle with a specific muscle involvement in patients with ACTA1 mutations. We investigated strictly noninvasively the gastrocnemius muscle function of a mouse model carrying a mutation in the ACTA1 gene (H40Y). Skeletal muscle anatomy (hindlimb muscles and fat volumes) and energy metabolism were studied using MRI and 31Phosphorus magnetic resonance spectroscopy. Skeletal muscle contractile performance was investigated while applying a force-frequency protocol (from 1–150 Hz) and a fatigue protocol (80 stimuli at 40 Hz). H40Y mice showed a reduction of both absolute (?40%) and specific (?25%) maximal force production as compared to controls. Interestingly, muscle weakness was associated with an improved resistance to fatigue (+40%) and an increased energy cost. On the contrary, the force frequency relationship was not modified in H40Y mice and the extent of fatty infiltration was minor and not different from the WT group. We concluded that the H40Y mouse model does not reproduce human MRI findings but shows a severe muscle weakness which might be related to an alteration of intrinsic muscular properties. The increased energy cost in H40Y mice might be related to either an impaired mitochondrial function or an alteration at the cross-bridges level. Overall, we provided a unique set of anatomic, metabolic and functional biomarkers that might be relevant for monitoring the progression of NM disease but also for assessing the efficacy of potential therapeutic interventions at a preclinical level.
Re Constructing and Celebrating the Louisiana Purchase in New Orleans
Jean?Pierre Le Glaunec
Transatlantica : Revue d'études Américaines , 2006,
Abstract: L’auteur s'est intéressé aux formes de célébrations/commémorations du bicentennaire de l’Achat de la Louisiane (1803) suite à un séjour de deux ans à l’Université de Tulane. Chercheur au Deep South Regional Humanities Center, il a participé sous la direction du Professeur Sylvia Frey à la création d’un CD-ROM (Louisiana State University, 2003) retra ant les mécanismes historiques, économiques, sociaux et culturels ayant précédés, accompagnés et suivis l’Achat de la Louisiane.Ce texte est issu d'une communication au colloque Stemming the Mississippi organisé par l’Institut Charles V de l’Université Paris 7. Il s’agit de la première étape d'un travail en cours sur la commémoration.
The 'epistemological incoherence' of management sciences La `incoherencia epistemológica' de las ciencias de la gestión
Le Moigne Jean Louis
Cuadernos de Economía , 1997,
Abstract: This article describes the dífficulties that management sciences have historically confronted to give epistemological legitimacy to their knowledges, and analyzes their possible contributions to contemporary epistemology. The various attempts to ground management sciences according to positivist precepts reflect an epistemological 'incoherence' which lessens their scientific credibility, but at the same time, in an age of crisis of the positivist paradigm, allows them to participate in the creation of constructivist epistemologies and, in that way, establish new mechanisms of legitimation of their knowledges. Este artículo describe las dificultades que las ciencias de gestión han enfrentado históricamente para dar legitimidad epistemológica a sus saberes y analiza sus posibles aportes a la epistemología contemporánea. Los diversos intentos de fundamentar las ciencias de gestión según los preceptos positivistas reflejan una 'incoherencia' epistemológica que les resta credibilidad cientificapero que la mismo tiempo, en una época de crisis del paradigma positivista, les permite participar en la creación de epistemologías constructivistas y, por esta vía, establecer nuevos mecanismos de legitimación de sus saberes.
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