60 research outputs found

    Dynamic parameters optimization of a Gough-Stewart Platform mounted on a 2-DOF moving base

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    International audienceA common issue of the parallel robot is that has a large number of dynamicparameters, which requires a lot of processing time, whether in dynamic modeling,identification or control. The optimization and estimation of inertial parametersof a large DoF number of robotic system is crucial to tune the model-basedcontrol law in order to improve the robot accuracy. In this paper, we present an optimizednumber of dynamic parameters, called base inertial parameters. As a result,only 90 base inertial parameters affect the evr@ simulator instead of 210 standardone. Torque signals evaluation from experimental parallel platform and the developedanalytical form show the effectiveness of the obtained results

    Prescription of Proton Pump Inhibitors in Elderly Subjects in Real Life: A Retrospective Study in a Gastroenterology Department

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    The proton-pump inhibitor (PPI) is an effective and widely used treatment but may cause side effects, especially for the elderly. Materials and methods: this is a cross-sectional study including 45 patients older than 65 years, followed at our outpatient and treated with PPIs for at least a year. The indication for PPI, the results of any endoscopy, and the quality of the tolerance of these molecules is specified by the data folder. During the consultation, we conducted an interrogation to an update of the history and medications to our patients and a type checking of the molecule, the dose, and the quality of the observance. Results: patients were divided into 32 women and 13 men with a mean age of 75 ± 7 years (65–92). The average length of PPI use was 6 ± 4 years (1–16) with a consumption of a double dose for at least 1 year in 28.8% of cases. The prescribed dose was higher than the recommended dose in at least 15.5% of cases. PPIs were well tolerated. One patient had presented a microscopic colitis, revealed by diarrhea regressed after discontinuation of PPIs. Conclusion: PPIs were prescribed in elderly subjects by gastroenterologists, in a university center, with a high dose and long. In our series, this treatment is well tolerated in the elderly

    Hepatoid adenocarcinoma of the gallbladder

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    Hepatoid adenocarcinoma is a rare variant of extrahepatic adenocarcinoma which behaves like hepatocellular carcinoma in morphology and functionality

    FANCA Gene Mutations in North African Fanconi Anemia Patients

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    Populations in North Africa (NA) are characterized by a high rate of consanguinity. Consequently, the proportion of founder mutations might be higher than expected and could be a major cause for the high prevalence of recessive genetic disorders like Fanconi anemia (FA). We report clinical, cytogenetic, and molecular characterization of FANCA in 29 North African FA patients from Tunisia, Libya, and Algeria. Cytogenetic tests revealed high rates of spontaneous chromosome breakages for all patients except two of them. FANCA molecular analysis was performed using three different molecular approaches which allowed us to identify causal mutations as homozygous or compound heterozygous forms. It included a nonsense mutation (c.2749C > T; p.Arg917Ter), one reported missense mutation (c.1304G > A; p.Arg435His), a novel missense variant (c.1258G > A; p.Asp409Glu), and the FANCA most common reported mutation (c.3788_3790delTCT; p.Phe1263del). Furthermore, three founder mutations were identified in 86.7% of the 22 Tunisian patients: (1) a deletion of exon 15, in 36.4% patients (8/22); (2), a deletion of exons 4 and 5 in 23% (5/22) and (3) an intronic mutation c.2222 + 166G > A, in 27.3% (6/22). Despite the relatively small number of patients studied, our results depict the mutational landscape of FA among NA populations and it should be taken into consideration for appropriate genetic counseling

    Organoiridium complexes : anticancer agents and catalysts

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    Iridium is a relatively rare precious heavy metal, only slightly less dense than osmium. Researchers have long recognized the catalytic properties of square-planar Ir(I) complexes, such as Crabtree's hydrogenation catalyst, an organometallic complex with cyclooctadiene, phosphane, and pyridine ligands. More recently, chemists have developed half-sandwich pseudo-octahedral pentamethylcyclopentadienyl Ir(III) complexes containing diamine ligands that efficiently catalyze transfer hydrogenation reactions of ketones and aldehydes in water using H2 or formate as the hydrogen source. Although sometimes assumed to be chemically inert, the reactivity of low-spin 5d(6) Ir(III) centers is highly dependent on the set of ligands. Cp* complexes with strong σ-donor C^C-chelating ligands can even stabilize Ir(IV) and catalyze the oxidation of water. In comparison with well developed Ir catalysts, Ir-based pharmaceuticals are still in their infancy. In this Account, we review recent developments in organoiridium complexes as both catalysts and anticancer agents. Initial studies of anticancer activity with organoiridium complexes focused on square-planar Ir(I) complexes because of their structural and electronic similarity to Pt(II) anticancer complexes such as cisplatin. Recently, researchers have studied half-sandwich Ir(III) anticancer complexes. These complexes with the formula [(Cp(x))Ir(L^L')Z](0/n+) (with Cp* or extended Cp* and L^L' = chelated C^N or N^N ligands) have a much greater potency (nanomolar) toward a range of cancer cells (especially leukemia, colon cancer, breast cancer, prostate cancer, and melanoma) than cisplatin. Their mechanism of action may involve both an attack on DNA and a perturbation of the redox status of cells. Some of these complexes can form Ir(III)-hydride complexes using coenzyme NAD(P)H as a source of hydride to catalyze the generation of H2 or the reduction of quinones to semiquinones. Intriguingly, relatively unreactive organoiridium complexes containing an imine as a monodentate ligand have prooxidant activity, which appears to involve catalytic hydride transfer to oxygen and the generation of hydrogen peroxide in cells. In addition, researchers have designed inert Ir(III) complexes as potent kinase inhibitors. Octahedral cyclometalated Ir(III) complexes not only serve as cell imaging agents, but can also inhibit tumor necrosis factor α, promote DNA oxidation, generate singlet oxygen when photoactivated, and exhibit good anticancer activity. Although relatively unexplored, organoiridium chemistry offers unique features that researchers can exploit to generate novel diagnostic agents and drugs with new mechanisms of action

    Modelisation et experimentation d'un actionneur lineaire a reluctance variable a champ longitudinal

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    SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 79265 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

    Sliding Movement Platform for Mixed Reality Application

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    International audienceThis paper deals with the conception of a new 6 DoF (Degree of Freedom) platform to reproducenatural motion feeling when the human is completely merged in mixed reality environments. The proposedsystem is open and supposed to be flexible and adaptable to three different applications: sport, health andrescue. In this paper, we focus on the sport simulation domain, namely the ski sliding movement. Wepresent the mechanical study of this platform, the 6 DOF motion modelling and some mechatronics aspects
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