1,658 research outputs found

    Three-axis force visualizing system for fiberscopes utilizing highly elastic fabric

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    This paper presents a novel force sensing system for fiberscopes. The key features of the system are its low cost, high resolution, small size, and ability to measure three-dimensional force. A previous study described a novel force sensing system that could be attached to a very thin fiberscope, based on a force visualization mechanism utilizing panty stocking fabric - a highly elastic material. However, this system measures force in only one direction. In this paper, the system is extended to measure forces in any of three directions. The system is targeted for application to neurosurgical examinations. It may also be useful for other medical and non-medical examinations that involve the use of fiberscopes. © 2014 IEEE.2014 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM 2014; Besancon; France; 8 July 2014 through 11 July 2014; Category numberCFP14775-ART; Code 10711

    Impact of post-procedural glycemic variability on cardiovascular morbidity and mortality after transcatheter aortic valve implantation : a post hoc cohort analysis

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    International audienceBackground : Glycemic variability is associated with worse outcomes after cardiac surgery, but the prognosis value of early glycemic variability after transcatheter aortic valve implantation is not known. This study was therefore designed to analyze the prognosis significance of post-procedural glycemic variability within 30 days after transcatheter aortic valve implantation.Methods : A post hoc analysis of patients from our center included in the FRANCE and FRANCE-2 registries was conducted. Post-procedural glycemic variability was assessed by calculating the mean daily δ blood glucose during the first 2 days after transcatheter aortic valve implantation. Major complications within 30 days were death, stroke, myocardial infarction, acute heart failure, and life-threatening cardiac arrhythmias.Results : We analyzed 160 patients (age (median [interquartile] = 84 [80–88] years; diabetes mellitus (n) = 41 (26%) patients; logistic Euroscore = 20 [12–32]). The median value of mean daily δ blood glucose was 4.3 mmol l−1. The rate of major complications within 30 days after procedure among patients with the lowest quartile of glycemic variability was 12%, increasing from 12 to 26%, and 39% in the second, third, and fourth quartiles, respectively. In multivariate analysis, glycemic variability was independently associated with an increased risk of major complications within 30 days after the procedure (odds ratio [95% CI] = 1.83 [1.19–2.83]; p = 0.006).Conclusions : This study showed that post-procedural glycemic variability was associated with an increased risk of major complications within 30 days after transcatheter aortic valve implantation

    Optically assisted trapping with high-permittivity dielectric rings: Towards optical aerosol filtration

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    Controlling the transport, trapping, and filtering of nanoparticles is important for many applications. By virtue of their weak response to gravity and their thermal motion, various physical mechanisms can be exploited for such operations on nanoparticles. However, the manipulation based on optical forces is potentially most appealing since it constitutes a highly deterministic approach. Plasmonic nanostructures have been suggested for this purpose, but they possess the disadvantages of locally generating heat and trapping the nanoparticles directly on surface. Here, we propose the use of dielectric rings made of high permittivity materials for trapping nanoparticles. Thanks to their ability to strongly localize the field in space, nanoparticles can be trapped without contact. We use a semi-analytical method to study the ability of these rings to trap nanoparticles. Results are supported by full-wave simulations. Application of the trapping concept to nanoparticle filtration is suggested.Comment: 5 figure

    Mitchell-Riley Syndrome : Improving Clinical Outcomes and Searching for Functional Impact of RFX-6 Mutations

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    Aims/HypothesisCaused by biallelic mutations of the gene encoding the transcription factor RFX6, the rare Mitchell-Riley syndrome (MRS) comprises neonatal diabetes, pancreatic hypoplasia, gallbladder agenesis or hypoplasia, duodenal atresia, and severe chronic diarrhea. So far, sixteen cases have been reported, all with a poor prognosis. This study discusses the multidisciplinary intensive clinical management of 4 new cases of MRS that survived over the first 2 years of life. Moreover, it demonstrates how the mutations impair the RFX6 function. MethodsClinical records were analyzed and described in detail. The functional impact of two RFX6(R181W) and RFX6(V506G) variants was assessed by measuring their ability to transactivate insulin transcription and genes that encode the L-type calcium channels required for normal pancreatic beta-cell function. ResultsAll four patients were small for gestational age (SGA) and prenatally diagnosed with duodenal atresia. They presented with neonatal diabetes early in life and were treated with intravenous insulin therapy before switching to subcutaneous insulin pump therapy. All patients faced recurrent hypoglycemic episodes, exacerbated when parenteral nutrition (PN) was disconnected. A sensor-augmented insulin pump therapy with a predictive low-glucose suspension system was installed with good results. One patient had a homozygous c.1517T>G (p.Val506Gly) mutation, two patients had a homozygous p.Arg181Trp mutation, and one patient presented with new compound heterozygosity. The RFX6(V506G) and RFX6(R181W) mutations failed to transactivate the expression of insulin and genes that encode L-type calcium channel subunits required for normal pancreatic beta-cell function. Conclusions/InterpretationMultidisciplinary and intensive disease management improved the clinical outcomes in four patients with MRS, including adjustment of parenteral/oral nutrition progression and advanced diabetes technologies. A better understanding of RFX6 function, in both intestine and pancreas cells, may break ground in new therapies, particularly regarding the use of drugs that modulate the enteroendocrine system.Peer reviewe

    The low mass population of the Vela OB2 association from Gaia

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    The first Gaia Data Release presents an opportunity to characterise the low-mass population of OB associations, providing larger statistical samples and better constraints on the formation and evolution of clusters and associations. Using previously known low mass members in a small region of Vela OB2 we have designed selection criteria that combine Gaia and 2MASS photometry, independently of any astrometric information, to identify low-mass pre-main-sequence (PMS) stars over the wider association area. Our method picks out the known clusters of young stars around Velorum and NGC-2547, but also identifies other over-densities that may represent previously unknown clusters. There are clear differences in the spatial distributions of the low-mass and the high-mass OB populations, suggesting either that the structure and dynamics of these populations has evolved separately or that the initial mass function can vary considerably on small scales within a single association

    Design and control of a GYRO stabilized pan-tilt sensor system for mobile applications

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    Pan-tilt platforms are the motion control systems mostly used for controlled positioning of various devices (video cameras, sensors, antennas) in mobile applications such as aerial video surveillance systems, mobile robots for emergency situations, space rovers, defense modules and many others. In this project, a spherical parallel manipulator (SPM) platform is studied for designing a 3DOF system of pure rotation for optimal platform orientations suitable for mobile applications. An optimal trajectory generation and an orientation stabilization control systems will be designed using Model Predictive Control techniques and implemented on the platform prototype

    Mobility of daughter elements of U-238 decay chain during leaching by In Situ Recovery (ISR) : New insights from digital autoradiography

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    In highly permeable sedimentary rock formations, U extraction by in-situ leaching techniques (ISR - In-Situ Recovery) is generally considered to have a limited environmental impact at ground level. Significantly, this method of extraction produces neither mill tailings nor waste rocks. Underground, however, the outcome for U-238 daughter elements in aquifers is not well known because of their trace concentrations in the host rocks. Thus, understanding the in-situ mobility of these elements remains a challenge. Two samples collected before and after six months of ISR experiments (Dulaan Uul, Mongolia) were studied with the help of a digital autoradiography technique (DA) of alpha particles, bulk alpha spectrometry, and complementary petrographic observation methods. These techniques demonstrate that before and after leaching, the radioactivity is concentrated in altered and microporous Fe-Ti oxides. Most of the daughter elements of U remain trapped in the rock after the leaching process. DA confirms that the alpha activity of the Fe-Ti oxides remains high after uranium leaching, and the initial secular equilibrium of the U-238 series for Th-230 to Po-210 daughter elements (including Ra-226) of the fresh rocks is maintained after leaching. While these findings should be confirmed by more systematic studies, they already identify potential mechanisms explaining why the U-daughter concentrations in leaching water are low.Peer reviewe
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