110 research outputs found

    Helicobacter pullorum cytolethal distending toxin targets vinculin and cortactin and triggers formation of lamellipodia in intestinal epithelial cells

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    Helicobacter pullorum, a bacterium initially isolated from poultry, has been associated with human digestive disorders. However, the factor responsible for its cytopathogenic effects on epithelial cells has not been formally identified. The cytopathogenic alterations induced by several human and avian H. pullorum strains were investigated on human intestinal epithelial cell lines. Moreover, the effects of the cytolethal distending toxin (CDT) were evaluated first by using a wild-type strain and its corresponding cdtB isogenic mutant and second by delivering the active CdtB subunit of the CDT directly into the cells. All of the H. pullorum strains induced cellular distending phenotype, actin cytoskeleton remodeling, and G2/M cell cycle arrest. These effects were dependent on the CDT, as they were (1) not observed in response to a cdtB isogenic mutant strain and (2) present in cells expressing CdtB. CdtB also induced an atypical delocalization of vinculin from focal adhesions to the perinuclear region, formation of cortical actin-rich large lamellipodia with an upregulation of cortactin, and decreased cellular adherence. In conclusion, the CDT of H. pullorum is responsible for major cytopathogenic effects in vitro, confirming its role as a main virulence factor of this emerging human pathogen.This work was supported by the Institut national de la santé et de la recherche médicale, the University Bordeaux Segalen, the Conseil Régional d’Aquitaine (grants 20030304002FA and 20040305003 FA), the Société Nationale Française de Gastroentérologie, the European Union (FEDER no. 2003227

    Learning valued relations from data

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    Driven by a large number of potential applications in areas like bioinformatics, information retrieval and social network analysis, the problem setting of inferring relations between pairs of data objects has recently been investigated quite intensively in the machine learning community. To this end, current approaches typically consider datasets containing crisp relations, so that standard classification methods can be adopted. However, relations between objects like similarities and preferences are in many real-world applications often expressed in a graded manner. A general kernel-based framework for learning relations from data is introduced here. It extends existing approaches because both crisp and valued relations are considered, and it unifies existing approaches because different types of valued relations can be modeled, including symmetric and reciprocal relations. This framework establishes in this way important links between recent developments in fuzzy set theory and machine learning. Its usefulness is demonstrated on a case study in document retrieval

    Systems and technologies for objective evaluation of technical skills in laparoscopic surgery

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    Minimally invasive surgery is a highly demanding surgical approach regarding technical requirements for the surgeon, who must be trained in order to perform a safe surgical intervention. Traditional surgical education in minimally invasive surgery is commonly based on subjective criteria to quantify and evaluate surgical abilities, which could be potentially unsafe for the patient. Authors, surgeons and associations are increasingly demanding the development of more objective assessment tools that can accredit surgeons as technically competent. This paper describes the state of the art in objective assessment methods of surgical skills. It gives an overview on assessment systems based on structured checklists and rating scales, surgical simulators, and instrument motion analysis. As a future work, an objective and automatic assessment method of surgical skills should be standardized as a means towards proficiency-based curricula for training in laparoscopic surgery and its certification

    InfoSyll: A Syllabary Providing Statistical Information on Phonological and Orthographic Syllables

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    here is now a growing body of evidence in various languages supporting the claim that syllables are functional units of visual word processing. In the perspective of modeling the processing of polysyllabic words and the activation of syllables, current studies investigate syllabic effects with subtle manipulations. We present here a syllabary of the French language aiming at answering new constraints when designing experiments on the syllable issue. The InfoSyll syllabary provides exhaustive characteristics and statistical information for each phonological syllable (e.g. /fi/) and for its corresponding orthographic syllables (e.g. fi, phi, phy, fee, fix, fis). Variables such as the type and token positional frequencies, the number and frequencies of the correspondences between orthographic and phonological syllables are provided. As discussed, such computations should allow precise controls, manipulations and quantitative descriptions of syllabic variables in the field of psycholinguistic research.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Open questions in utility theory

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    Throughout this paper, our main idea is to explore different classical questions arising in Utility Theory, with a particular attention to those that lean on numerical representations of preference orderings. We intend to present a survey of open questions in that discipline, also showing the state-of-art of the corresponding literature.This work is partially supported by the research projects ECO2015-65031-R, MTM2015-63608-P (MINECO/ AEI-FEDER, UE), and TIN2016-77356-P (MINECO/ AEI-FEDER, UE)

    Introduction to the mathematical theory of knowledge conceptualization: Conceptual systems and structures

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    The paper departs from the general problem of knowledge integration and the basic strategies that can be adopted to confront this challenge. With the purpose of providing a sound meta-theoretical framework to facilitate knowledge conceptualization and integration, as well as assessment criteria to evaluate achievements regarding knowledge integration, the paper first reviews the previous work in the field of conceptual spaces. It subsequently gives an overview of structural tools and mechanisms for knowledge representation, recapped in the modal stratified bond model of global knowledge. On these groundings, a novel formalized representation of conceptual systems, structures, spaces and algebras is developed through a set of definitions which goes beyond the exploration of mental knowledge representation and the semantics of natural languages. These two components provide a sound framework for the development of the glossaLAB international project with respect to its two basic objectives, namely (i) facilitating knowledge integration in general and particularly in the context of the general study of information and systems; (ii) facilitating the assessment of the achievements as regards knowledge integration in interdisciplinary settings. An additional article tackles the solutions adopted to integrate these results in the elucidation of the conceptual network of the general study of information and systems.2019-2

    Action des inhibiteurs de la biosynthèse de l'ergostérol sur la fermentation alcoolique du moût de raisin blanc

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    Les fongicides appartenant aux familles des Triazoles et Imidazoles agissent en bloquant la voie de biosynthèse de l'ergostérol chez les champignons parasites de la vigne. Ils sont très utilisés pour lutter contre l'oïdium et le black-rot; mais ces fongicides perturbent la maturation des raisins traités, ainsi que la fermentation alcoolique en induisant chez la levure des modifications du métabolisme des acides gras et des stérols, modifiant ainsi la composition lipidique. On constate dans la pratique que des résidus de ces fongicides se retrouvent dans les moûts de vigne traitée et ralentissent la vitesse de fermentation. Une conséquence est l'augmentation de la fréquence des arrêts de fermentation outre, des modifications concernant les qualités organoleptiques des vins issus de ces raisins

    <i>Telestacicola xenophiothricics</i> n. sp. (Copepoda, Poecilostomatoida), a remarkably well adapted commensal of the brittlestar <i>Ophiothrix purpurea</i> (Echinodermata)

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    A study of the turbellarian commensal fauna of the brittlestar Ophiothrix purpurea in Hansa Bay (Papua New Guinea) revealed the presence of a remarkably well-adapted lichomolgid copepod Telestacicola xenophiothricis n. sp. (Rynchomolgidae, Poecilostomatoida). Fourteen out of 118 (12%) ophiuroids inspected were infested by one to three copepods ( a total of 18 specimens observed). The body colour of this commensal crustacean mimics perfectly the pattern of orange-red and pink lines of the central disk of the host, and this complex and uncommon mimicry could indicate a high host specificity. T. xenophiothricis is the fourth member in this genus, but is the first encountered on ophiuroids (Echinodermata), while it is the tenth species of Poecilostomatoida amongst the 46 known species of Copepoda associated with ophiuroids (others are 22 Siphonostomatoida, 13 Cyclopoida and one Harpacticoida). Furthermore, the generic assignment of Doridicola claudus Humes & Stock is discussed, and the species is allocated to the genus Telestacicola

    Model-based 3-D Pose Estimation and Feature Tracking for Robot Assisted Surgery with Medical Imaging

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    Abstract — In this paper we address the problem of the pose estimation based on multiple geometrical features for monocular endoscopic vision with laparoscopes and for stereotaxy with CT scanners. Partial and full pose estimation (6 dofs) are considered with applications to minimally invasive surgery. At the University of Strasbourg, we have been developing a set of techniques for assisting surgeons in navigating and manipulating the three-dimensional space within the human body. In order to develop such systems, a variety of challenging visual tracking and registration problems with pre-operative and/or intra-operative images must be solved. This paper integrates several issues where computational vision can play a role. Depth recovery (from the tip of a surgical instrument w.r.t. living tissue), the Plücker coordinates (4 dofs) of a markerless cylindrical instrument, the 6 dofs of a needle-holder with an heterogeneous set of features and stereotaxy are the examples we describe. Projective invariants with perspective projection, quadrics of revolution and stereotactic markers are features which are useful to achieve the registration with uncalibrated or calibrated devices. Visual servoing-based tracking methods have been developed for image-guided robotic systems, for assisting surgeons in laparoscopic surgery and in interventional radiology. Real-time endoscopic vision and single-slice stereotactic registration has been proposed to retrieve the out-of-field of view instruments, to position a needle and to compensate small displacements like those due to patient breathing or any small disturbances which may occur during an image-guided surgical procedure. I
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