175 research outputs found

    Visual loss related to macular subretinal fluid and cystoid macular edema in HIV-related optic neuropathy

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    Optic nerve involvement may occur in various infectious diseases, but is rarely reported after infection by the human immunodeficiency virus (HIV). We report the atypical case of a 38-year-old patient in whom the presenting features of HIV infection were due to a bilateral optic neuropathy associated with macular subretinal fluid and cystoid macular edema, which responded well to antiretroviral therapy

    F-02: Antibiothérapies anti-SARM dans le traitement probabiliste des bactériémies à Staphylococcus aureus au CHU d'Angers

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    Introduction – objectifs La résistance à la méticilline du Staphylococcus aureus (SA) ne cesse de diminuer en France. Nous avons évalué la prescription des antibiothérapies probabilistes dans les bactériémies à SA et leur impact clinique. Matériels et méthodes Il s’agit d’une étude rétrospective incluant les bactériémies à Staphylococcus aureus sur le CHU d’Angers entre novembre 2012 et septembre 2013 avec recueil de l’antibiothérapie prescrite au rendu « cocci gram (CG)+ », à J5, hospitalisation depuis plus de 5 jours ou dans les six derniers mois, signes de gravité clinique, mortalité à J5. Résultats Nous avons inclus 146 épisodes de bactériémies. A l’annonce de CG+, 10 patients étaient décédés, 38,2 % ont reçu un anti-SARM (n = 52), 54,4 % un anti-SASM (n = 74), 7,4 % aucun antibiotique (n = 10). Parmi les bactériémies à SARM (n = 23), 60,9 % (n = 14) ont reçu une antibiothérapie initiale à visée SARM contre 36,3 % (n = 41) pour les bactériémies à SASM (n = 113) (OR = 2,71, p = 0,03). Cette adaptation semble influencée par une hospitalisation récente (OR = 1,82 ; p = 0,33) et la présence de signes de gravité (OR = 1,87, p = 0,23). Dans 21,4 % (n = 6) des bactériémies à SASM, l’antibiothérapie anti-SARM n’a pas été désecaladée. La mortalité à J5 est 13 %. L’absence d’antibiothérapie dans les 24 premières heures (OR = 2,97 ; p = 0,046) et une prescription de C3G (OR = 5,2, p = 0,05) en monothérapie augmentent le risque de décès à J5. Conclusion L’antibiothérapie initale semble adaptée à l’histoire et la présentation des patients. L’initiation sans délai, la visée staphylococcique et la désescalade sont les éléments importants du traitement

    Pinning and trapped field in MgB2- and MT-YBaCuO bulk superconductors manufactured under pressure

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    The relevant pinning centers of Abrikosov vortices in MgB2_{2}–based materials are oxygen-enriched Mg-B-O inclusions or nanolayers and inclusions of MgBx_{x} (x>4) phases. The high critical current densities, jc_{c}, of 106^{6} and 103^{3}A/cm2^{2} at 1 and 8.5 T, respectively, at 20 K can be achieved in polycrystalline materials (prepared at 2 GPa) containing a large amount of admixed oxygen. Besides, oxygen can be incorporated into the MgB2_{2} structure in small amounts (MgB1.5_{1.5}O0.5_{0.5}), which is supported by Auger studies and calculations of the DOS and the binding energy. The jc_{c} of melt textured YBa2_{2}Cu3_{3}O7−δ_{7-δ } (or Y123)-based superconductors (MT-YBaCuO) depends not only on the perfectness of texture and the amount of oxygen in the Y123 structure, but also on the density of twins and micro-cracks formed during the oxygenation (due to shrinking of the c-lattice parameter). The density of twins and microcracks increases with the reduction of the distance between Y2_{2}BaCuO5_{5} (Y211) inclusions in Y123. At 77 K jc_{c}=8⋅104^{4} A/cm2^{2} in self-field and jc_{c}=103^{3} A/cm2^{2} at 10 Т were found in materials oxygenated at 16 MPa for 3 days with a density of twins of 22–35 per μm (thickness of the lamellae: 45-30 nm) and a density of micro-cracks of 200–280 per mm. Pinning can occur at the points of intersection between the Y123 twin planes and the Y211 inclusions. MTYBaCuO at 77 K can trap 1.4 T (38×38×17 mm, oxygenated at 0.1 MPa for 20 days) and 0.8 T (16 mm in diameter and 10 mm thick with 0.45 mm holes oxygenated at 10 MPa for 53 h). The sensitivity of MgB2_{2} to magnetic field variations (flux jumps) complicates estimates of the trapped field. At 20 K 1.8 T was found for a block of 30 mm in diameter and a thickness of 7.5 mm and 1.5 T (if the magnetic field was increased at a rate of 0.1 T) for a ring with dimensions 24×18 mm and a thickness of 8 mm

    Calcitization of aragonitic bryozoans in Cenozoic tropical carbonates from East Kalimantan, Indonesia

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    © The Author(s) 2016. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The file attached is the published version of the article

    Normal forms and internal regularization of nonlinear differential-algebraic control systems

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    In this article, we propose two normal forms for nonlinear differential-algebraic control systems (DACSs) under external feedback equivalence, using a notion called maximal controlled invariant submanifold. The two normal forms simplify the system structures and facilitate understanding the various roles of variables for nonlinear DACSs. Moreover, we study when a given nonlinear DACS is internally regularizable, that is, when there exists a state feedback transforming the DACS into a differential-algebraic equation (DAE) with internal regularity, the latter notion is closely related to the existence and uniqueness of solutions of DAEs. We also revise a commonly used method in DAE solution theory, called the geometric reduction method. We apply this method to DACSs and formulate it as an algorithm, which is used to construct maximal controlled invariant submanifolds and to find internal regularization feedbacks. Two examples of mechanical systems are used to illustrate the proposed normal forms and to show how to internally regularize DACSs

    A case report of Mycoplasma hominis brain abscess identified by MALDI-TOF mass spectrometry

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    We report the case of a 43-year-old man with a Mycoplasma hominis brain abscess occurring after a cranial trauma, which was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The presence of colonies on classic blood agar plates and the use of MALDI-TOF MS, a valuable diagnostic tool that identified M. hominis due to its presence in the VITEK MS database, allowed the rapid diagnosis of this infection

    Site testing for submillimetre astronomy at Dome C, Antarctica

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    Over the past few years a major effort has been put into the exploration of potential sites for the deployment of submillimetre astronomical facilities. Amongst the most important sites are Dome C and Dome A on the Antarctic Plateau, and the Chajnantor area in Chile. In this context, we report on measurements of the sky opacity at 200 um over a period of three years at the French-Italian station, Concordia, at Dome C, Antarctica. We also present some solutions to the challenges of operating in the harsh polar environ- ment. Dome C offers exceptional conditions in terms of absolute atmospheric transmission and stability for submillimetre astron- omy. Over the austral winter the PWV exhibits long periods during which it is stable and at a very low level (0.1 to 0.3 mm). Higher values (0.2 to 0.8 mm) of PWV are observed during the short summer period. Based on observations over three years, a transmission of around 50% at 350 um is achieved for 75% of the time. The 200-um window opens with a typical transmission of 10% to 15% for 25% of the time. Dome C is one of the best accessible sites on Earth for submillimetre astronomy. Observations at 350 or 450 {\mu}m are possible all year round, and the 200-um window opens long enough and with a sufficient transparency to be useful. Although the polar environment severely constrains hardware design, a permanent observatory with appropriate technical capabilities is feasible. Because of the very good astronomical conditions, high angular resolution and time series (multi-year) observations at Dome C with a medium size single dish telescope would enable unique studies to be conducted, some of which are not otherwise feasible even from space

    CALIPSO observations of wave-induced PSCs with near-unity optical depth over Antarctica in 2006-2007

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    International audienceGround-based and satellite observations have hinted at the existence of polar stratospheric clouds (PSCs) with relatively high optical depths, even if optical depth values are hard to come by. This study documents a type II PSC observed from spaceborne lidar, with visible optical depths up to 0.8. Comparisons with multiple temperature fields, including reanalyses and results from mesoscale simulations, suggest that intense small-scale temperature fluctuations due to gravity waves play an important role in its formation, while nearby observations show the presence of a potentially related type Ia PSC farther downstream inside the polar vortex. Following this first case, the geographic distribution and microphysical properties of PSCs with optical depths above 0.3 are explored over Antarctica during the 2006 and 2007 austral winters. These clouds are rare (less than 1% of profiles) and concentrated over areas where strong winds hit steep ground slopes in the Western Hemisphere, especially over the peninsula. Such PSCs are colder than the general PSC population, and their detection is correlated with daily temperature minima across Antarctica. Lidar and depolarization ratios within these clouds suggest they are most likely ice-based (type II). Similarities between the case study and other PSCs suggest they might share the same formation mechanisms

    Effects of the combination of camptothecin and doxorubicin or etoposide on rat glioma cells and camptothecin-resistant variants

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    From the rat C6 glioma cell line in culture, we selected camptothecin-resistant variants by growth in the presence of increasing amounts of this drug (C6CPT10, C6CPT50 and C6CPT100, growing respectively with 10, 50 and 100 ng ml–1camptothecin). The degree of resistance to camptothecin ranged between 15-fold (C6CPT10) and 30-fold (C6CPT50and C6CPT100). The C6CPT10cell line presented a collateral sensitivity to etoposide (3.6-fold), while the C6CPT50 and C6CPT100 cell lines were cross-resistant to etoposide (1.8-fold) The resistant lines were characterised by a two-fold reduced content and catalytic activity of topoisomerase I, and C6CPT50 and C6CPT100 presented a significant increase in topoisomerase IIα content and catalytic activity and a marked overexpression of P-glycoprotein. We explored the cytotoxicity of combinations of a topoisomerase I inhibitor (camptothecin) and a topoisomerase II inhibitor (doxorubicin or etoposide) at several molar ratios, allowing the evaluation of their synergistic or antagonistic effects on cell survival using the median effect principle. The simultaneous combination of camptothecin and doxorubicin or etoposide was additive or antagonistic in C6 cells, slightly synergistic in the C6CPT10 line and never more than additive in the C6CPT50 and C6CPT100 cell lines. The sequential combination of doxorubicin and camptothecin gave additivity in the order camptothecin → doxorubicin and antagonism in the order doxorubicin → camptothecin. Clinical protocols combining a topoisomerase I and a topoisomerase II inhibitor should be considered with caution because antagonistic effects have been observed with combinations of camptothecin and doxorubicin.© 2001 Cancer Research Campaign http://www.bjcancer.co
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