147 research outputs found

    Une approche multi-agents coopératifs pour la gestion des ressources matérielles dans un contexte multi-sites de e-manufacturing.

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    International audienceDans cet article, nous proposons une modélisation basée sur le paradigme des systèmes multi-agents coopératifs appliquée à la gestion de ressources matérielles distribuées dans un environnement d'entreprises multisites distribués. Cette gestion constitue actuellement un challenge pour tous les producticiens du fait des influences économiques et technologiques modernes qui affectent ce genre d'entreprises. En effet, la redondance d'un stock d'un article quelconque dans plusieurs sites affecte négativement la santé économique de l'entreprise en tout, ce qui nous pousse à la recherche de méthodes optimales pouvant assurer un équilibrage de charge en matière de ces ressources entre les différents sites. Pour cela nous exploitons la plateforme Internet reliant les sites et en appliquant la technologie des Web Services basée sur les agents (agent demandeur, agent fournisseur et agent annuaire), nous mettrons en oeuvre une dynamique de coopération entre site déficitaire en article k et site excédentaire du même article et en généralisant ce principe à tous les articles, nous réaliserons l'équilibrage dynamique pouvant éviter à l'entreprise les sur-stockages et les sous-stockags de ces ressources matérielles

    Widespread Wolbachia infection in terrestrial isopods and other crustaceans

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    Wolbachia bacteria are obligate intracellular alpha-Proteobacteria of arthropods and nematodes. Although widespread among isopod crustaceans, they have seldom been found in non-isopod crustacean species. Here, we report Wolbachia infection in fourteen new crustacean species. Our results extend the range of Wolbachia infections in terrestrial isopods and amphipods (class Malacostraca). We report the occurrence of two different Wolbachia strains in two host species (a terrestrial isopod and an amphipod). Moreover, the discovery of Wolbachia in the goose barnacle Lepas anatifera (subclass Thecostraca) establishes Wolbachia infection in class Maxillopoda. The new bacterial strains are closely related to B-supergroup Wolbachia strains previously reported from crustacean hosts. Our results suggest that Wolbachia infection may be much more widespread in crustaceans than previously thought. The presence of related Wolbachia strains in highly divergent crustacean hosts suggests that Wolbachia endosymbionts can naturally adapt to a wide range of crustacean hosts. Given the ability of isopod Wolbachia strains to induce feminization of genetic males or cytoplasmic incompatibility, we speculate that manipulation of crustacean-borne Wolbachia bacteria might represent potential tools for controlling crustacean species of commercial interest and crustacean or insect disease vectors.This research was funded by a European Research Council Starting Grant (FP7/2007-2013 grant 260729 EndoSexDet) to RC and a Comité Mixte de Coopération Universitaire Franco-Tunisien grant to DB and FCC

    A prediction rule for lack of achievement of inactive disease with methotrexate as the sole disease-modifying antirheumatic therapy in juvenile idiopathic arthritis

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    Background: To investigate the frequency of achievement of inactive disease (ID) in children with juvenile idiopathic arthritis (JIA) treated with methotrexate (MTX) as the sole disease-modifyng antirheumatic (DMARD) therapy and to develop a prediction model for lack of attainment of ID. Methods: The clinical charts of consecutive patients started with MTX as the sole DMARD between 2000 and 2013 were reviewed. Patient follow-up was censored at first episode of ID or, in case ID was not reached, at last follow-up visit or when a biologic DMARD was prescribed. The characteristic at MTX start of patients who achieved or did not achieve ID were compared with univariate and multivariable analyses. Regression coefficients (\u3b2) of variables that entered the best-fitting logistic regression model were converted and summed to obtain a "prediction score" for lack of achievement of ID. Results: A total of 375 patients were included in the study. During MTX administration, 8.8% were given systemic corticosteroids and 44.1% intra-articular corticosteroids. After MTX start, 229 (61%) patients achieved ID after a median of 1.7 years, whereas 146 patients (39%) did not reach ID after a median of 1.2 years. On multivariable analysis, independent correlations with lack of achievement of ID were identified for the disease categories of systemic arthritis, enthesitis-related arthritis (ERA) and polyarthritis and C-reactive protein (CRP) > 1.4 mg/dl. The prediction score ranged from 0 to 3 and its cutoff that discriminated best between patients who achieved or did not achieve ID was > 0.5. The categories of systemic arthritis or ERA, both of which had a score greater than 0.5, were sufficient alone to predict a lower likelihood to reach ID. Polyarthritis and increased CRP, whose score was 0.5, assumed a predictive value only when present in association. Conclusion: A conventional treatment regimen based on MTX as the sole DMARD led to achievement of ID in a sizeable proportion of children with JIA. Our findings help to outline the characteristics of patients who may deserve a synthetic DMARD other than MTX or the introduction of a biologic DMARD from disease outset

    Wolbachia in the flesh: symbiont intensities in germ-line and somatic tissues challenge the conventional view of Wolbachia transmission routes

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    Symbionts can substantially affect the evolution and ecology of their hosts. The investigation of the tissue-specific distribution of symbionts (tissue tropism) can provide important insight into host-symbiont interactions. Among other things, it can help to discern the importance of specific transmission routes and potential phenotypic effects. The intracellular bacterial symbiont Wolbachia has been described as the greatest ever panzootic, due to the wide array of arthropods that it infects. Being primarily vertically transmitted, it is expected that the transmission of Wolbachia would be enhanced by focusing infection in the reproductive tissues. In social insect hosts, this tropism would logically extend to reproductive rather than sterile castes, since the latter constitute a dead-end for vertically transmission. Here, we show that Wolbachia are not focused on reproductive tissues of eusocial insects, and that non-reproductive tissues of queens and workers of the ant Acromyrmex echinatior, harbour substantial infections. In particular, the comparatively high intensities of Wolbachia in the haemolymph, fat body, and faeces, suggest potential for horizontal transmission via parasitoids and the faecal-oral route, or a role for Wolbachia modulating the immune response of this host. It may be that somatic tissues and castes are not the evolutionary dead-end for Wolbachia that is commonly thought

    Stratification of Patients With Sjögren’s Syndrome and Patients With Systemic Lupus Erythematosus According to Two Shared Immune Cell Signatures, With Potential Therapeutic Implications

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    OBJECTIVE: Similarities in the clinical and laboratory features of patients with primary Sjögren's syndrome (pSS) and systemic lupus erythematosus (SLE) have led to attempts to treat pSS and SLE patients with similar biologic therapeutics. However, the results of many clinical trials are disappointing, and no biologic treatments are licensed in pSS, while few are available for SLE patients with refractory disease. Identifying shared immunological features between pSS and SLE could lead to better treatment selection using a stratification approach. METHODS: Immune-phenotyping of 29 immune-cell subsets in peripheral blood from patients with pSS (n=45), SLE (n=29) and secondary SS associated with SLE (SLE/SS) (n=14) with low disease activity or in clinical remission, and sex-matched healthy controls (n=31), was performed using flow cytometry. Data were analysed using supervised machine learning (balanced random forest, sparse partial least squares discriminant analysis), logistic regression and multiple t-tests. Patients were stratified by k-means clustering, and clinical trajectory analysis. RESULTS: Patients with pSS and SLE had a similar immunological architecture despite having different clinical presentations and prognosis. K-means cluster analysis of the combined pSS, SLE and SLE/SS patient cohorts identified two endotypes characterized by distinct immune-cell profiles which spanned patient diagnoses. Logistic regression and machine learning models identified a signature of eight T-cell subsets that differentiated between the two endotypes with high accuracy (AUC=0.9979). Baseline and five-year clinical trajectory analysis identified differential damage scores and disease activity between the two endotypes. CONCLUSION: An immune-cell toolkit could differentiate patients across diseases with high accuracy for targeted therapeutic approaches

    Intense Transpositional Activity of Insertion Sequences in an Ancient Obligate Endosymbiont

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    The streamlined genomes of ancient obligate endosymbionts generally lack transposable elements, such as insertion sequences (IS). Yet, the genome of Wolbachia, one of the most abundant bacterial endosymbionts on Earth, is littered with IS. Such a paradox raises the question as to why there are so many ISs in the genome of this ancient endosymbiont. To address this question, we investigated IS transpositional activity in the unculturable Wolbachia by tracking the evolutionary dynamics and history of ISWpi1 elements. We show that 1) ISWpi1 is widespread in Wolbachia, being present in at least 55% of the 40 sampled strains, 2) ISWpi1 copies exhibit virtually identical nucleotide sequences both within and among Wolbachia genomes and possess an intact transposase gene, 3) individual ISWpi1 copies are differentially inserted among Wolbachia genomes, and 4) ISWpi1 occurs at variable copy numbers among Wolbachia genomes. Collectively, our results provide compelling evidence for intense ISWpi1 transpositional activity and frequent ISWpi1 horizontal transmission among strains during recent Wolbachia evolution. Thus, the genomes of ancient obligate endosymbionts can carry high loads of functional and transpositionally active transposable elements. Our results also indicate that Wolbachia genomes have experienced multiple and temporally distinct ISWpi1 invasions during their evolutionary history. Such recurrent exposition to new IS invasions may explain, at least partly, the unusually high density of transposable elements found in the genomes of Wolbachia endosymbionts

    The Immune Cellular Effectors of Terrestrial Isopod Armadillidium vulgare: Meeting with Their Invaders, Wolbachia

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    Most of crustacean immune responses are well described for the aquatic forms whereas almost nothing is known for the isopods that evolved a terrestrial lifestyle. The latter are also infected at a high prevalence with Wolbachia, an endosymbiotic bacterium which affects the host immune system, possibly to improve its transmission. In contrast with insect models, the isopod Armadillidium vulgare is known to harbor Wolbachia inside the haemocytes.In A. vulgare we characterized three haemocyte types (TEM, flow cytometry): the hyaline and semi-granular haemocytes were phagocytes, while semi-granular and granular haemocytes performed encapsulation. They were produced in the haematopoietic organs, from central stem cells, maturing as they moved toward the edge (TEM). In infected individuals, live Wolbachia (FISH) colonized 38% of the haemocytes but with low, variable densities (6.45±0.46 Wolbachia on average). So far they were not found in hyaline haemocytes (TEM). The haematopoietic organs contained 7.6±0.7×10(3)Wolbachia, both in stem cells and differentiating cells (FISH). While infected and uninfected one-year-old individuals had the same haemocyte density, in infected animals the proportion of granular haemocytes in particular decreased by one third (flow cytometry, Pearson's test = 12 822.98, df = 2, p<0.001).The characteristics of the isopod immune system fell within the range of those known from aquatic crustaceans. The colonization of the haemocytes by Wolbachia seemed to stand from the haematopoietic organs, which may act as a reservoir to discharge Wolbachia in the haemolymph, a known route for horizontal transfer. Wolbachia infection did not affect the haemocyte density, but the quantity of granular haemocytes decreased by one third. This may account for the reduced prophenoloxidase activity observed previously in these animals

    No effect of glutamine supplementation and hyperoxia on oxidative metabolism and performance during high-intensity exercise.

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    addresses: Health and Biology, Liverpool Hope University, Liverpool, UK. [email protected]: Comparative Study; Journal ArticleThis is an Author's Accepted Manuscript of an article published in Journal of Sports Sciences, 2008, Vol. 26, Issue 10, pp. 1081 – 1090 © 2008 copyright Taylor & Francis, available online at: http://www.tandfonline.com/doi/abs/10.1080/02640410801930200Glutamine enhances the exercise-induced expansion of the tricarboxylic acid intermediate pool. The aim of the present study was to determine whether oral glutamine, alone or in combination with hyperoxia, influenced oxidative metabolism and cycle time-trial performance. Eight participants consumed either placebo or 0.125 g kg body mass(-1) of glutamine in 5 ml kg body mass(-1) placebo 1 h before exercise in normoxic (control and glutamine respectively) or hyperoxic (FiO(2) = 50%; hyperoxia and hyperoxia + glutamine respectively) conditions. Participants then cycled for 6 min at 70% maximal oxygen uptake (VO(2max)) immediately before completing a brief high-intensity time-trial (approximately 4 min) during which a pre-determined volume of work was completed as fast as possible. The increment in pulmonary oxygen uptake during the performance test (DeltaVO(2max), P = 0.02) and exercise performance (control: 243 s, s(x) = 7; glutamine: 242 s, s(x) = 3; hyperoxia: 231 s, s(x) = 3; hyperoxia + glutamine: 228 s, s(x) = 5; P < 0.01) were significantly improved in hyperoxic conditions. There was some evidence that glutamine ingestion increased DeltaVO(2max) in normoxia, but not hyperoxia (interaction drink/FiO(2), P = 0.04), but there was no main effect or impact on performance. Overall, the data show no effect of glutamine ingestion either alone or in combination with hyperoxia, and thus no limiting effect of the tricarboxylic acid intermediate pool size, on oxidative metabolism and performance during maximal exercise

    Protein and Overtraining: Potential Applications for Free-Living Athletes

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    Despite a more than adequate protein intake in the general population, athletes have special needs and situations that bring it to the forefront. Overtraining is one example. Hard-training athletes are different from sedentary persons from the sub-cellular to whole-organism level. Moreover, competitive, "free-living" (less-monitored) athletes often encounter negative energy balance, sub-optimal dietary variety, injuries, endocrine exacerbations and immune depression. These factors, coupled with "two-a-day" practices and in-season demands require that protein not be dismissed as automatically adequate or worse, deleterious to health. When applying research to practice settings, one should consider methodological aspects such as population specificity and control variables such as energy balance. This review will address data pertinent to the topic of athletic protein needs, particularly from a standpoint of overtraining and soft tissue recovery. Research-driven strategies for adjusting nutrition and exercise assessments will be offered for consideration. Potentially helpful nutrition interventions for preventing and treating training complications will also be presented
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