106 research outputs found

    Single step synthesis and organization of gold colloids assisted by copolymer templates

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    We report here an original single-step process for synthesis and self-organization of gold colloids by simply incorporating gold salts into a solution prepared with Polystyrene (PS) - Polymethylmethacrylate (PMMA) copolymer, thiolated PS and Propylene Glycol Methyl Ether Acetate (PGMEA) as solvent. The spin-coating and annealing of this solution allows then the formation of PS domains. Depending on the polymer concentration of the as-prepared solution, there can be either one or several gold nanoparticles (NPs) per PS domains. For high concentration of gold nanoparticles in PS domains, the coupling between plasmonic nanoparticles leads to the observation of second peak in the optical extinction spectrum. Such collective effect could be relevant for the development of optical strain sensors in the next future.Comment: 8 pages, 6 figure

    A new HPF specimen carrier adapter for the use of high-pressure freezing with cryo-scanning electron microscope: two applications: stearic acid organization in a hydroxypropyl methylcellulose matrix and mice myocardium .

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    Cryogenic transmission electron microscopy of high-pressure freezing (HPF) samples is a well-established technique for the analysis of liquid containing specimens. This technique enables observation without removing water or other volatile components. The HPF technique is less used in scanning electron microscopy (SEM) due to the lack of a suitable HPF specimen carrier adapter. The traditional SEM cryotransfer system (PP3000T Quorum Laughton, East Sussex, UK; Alto Gatan, Pleasanton, CA, USA) usually uses nitrogen slush. Unfortunately, and unlike HPF, nitrogen slush produces water crystal artefacts. So, we propose a new HPF specimen carrier adapter for sample transfer from HPF system to cryogenic-scanning electronic microscope (Cryo-SEM). The new transfer system is validated using technical two applications, a stearic acid in hydroxypropyl methylcellulose solution and mice myocardium. Preservation of samples is suitable in both cases. Cryo-SEM examination of HPF samples enables a good correlation between acid stearic liquid concentration and acid stearic occupation surface (only for homogeneous solution). For biological samples as myocardium, cytoplasmic structures of cardiomyocyte are easily recognized with adequate preservation of organelle contacts and inner cell organization. We expect this new HPF specimen carrier adapter would enable more SEM-studies using HPF

    Roadless and Low-Traffic Areas as Conservation Targets in Europe

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    With increasing road encroachment, habitat fragmentation by transport infrastructures has been a serious threat for European biodiversity. Areas with no roads or little traffic (“roadless and low-traffic areas”) represent relatively undisturbed natural habitats and functioning ecosystems. They provide many benefits for biodiversity and human societies (e.g., landscape connectivity, barrier against pests and invasions, ecosystem services). Roadless and low-traffic areas, with a lower level of anthropogenic disturbances, are of special relevance in Europe because of their rarity and, in the context of climate change, because of their contribution to higher resilience and buffering capacity within landscape ecosystems. An analysis of European legal instruments illustrates that, although most laws aimed at protecting targets which are inherent to fragmentation, like connectivity, ecosystem processes or integrity, roadless areas are widely neglected as a legal target. A case study in Germany underlines this finding. Although the Natura 2000 network covers a significant proportion of the country (16%), Natura 2000 sites are highly fragmented and most low-traffic areas (75%) lie unprotected outside this network. This proportion is even higher for the old Federal States (western Germany), where only 20% of the low-traffic areas are protected. We propose that the few remaining roadless and low-traffic areas in Europe should be an important focus of conservation efforts; they should be urgently inventoried, included more explicitly in the law and accounted for in transport and urban planning. Considering them as complementary conservation targets would represent a concrete step towards the strengthening and adaptation of the Natura 2000 network to climate change

    Impact of early enteral versus parenteral nutrition on mortality in patients requiring mechanical ventilation and catecholamines: study protocol for a randomized controlled trial (NUTRIREA-2)

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    BACKGROUND: Nutritional support is crucial to the management of patients receiving invasive mechanical ventilation (IMV) and the most commonly prescribed treatment in intensive care units (ICUs). International guidelines consistently indicate that enteral nutrition (EN) should be preferred over parenteral nutrition (PN) whenever possible and started as early as possible. However, no adequately designed study has evaluated whether a specific nutritional modality is associated with decreased mortality. The primary goal of this trial is to assess the hypothesis that early first-line EN, as compared to early first-line PN, decreases day 28 all-cause mortality in patients receiving IMV and vasoactive drugs for shock. METHODS/DESIGN: The NUTRIREA-2 study is a multicenter, open-label, parallel-group, randomized controlled trial comparing early PN versus early EN in critically ill patients requiring IMV for an expected duration of at least 48 hours, combined with vasoactive drugs, for shock. Patients will be allocated at random to first-line PN for at least 72 hours or to first-line EN. In both groups, nutritional support will be started within 24 hours after IMV initiation. Calorie targets will be 20 to 25 kcal/kg/day during the first week, then 25 to 30 kcal/kg/day thereafter. Patients receiving PN may be switched to EN after at least 72 hours in the event of shock resolution (no vasoactive drugs for 24 consecutive hours and arterial lactic acid level below 2 mmol/L). On day 7, all patients receiving PN and having no contraindications to EN will be switched to EN. In both groups, supplemental PN may be added to EN after day 7 in patients with persistent intolerance to EN and inadequate calorie intake. We plan to recruit 2,854 patients at 44 participating ICUs. DISCUSSION: The NUTRIREA-2 study is the first large randomized controlled trial designed to assess the hypothesis that early EN improves survival compared to early PN in ICU patients. Enrollment started on 22 March 2013 and is expected to end in November 2015. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01802099 (registered 27 February 2013)

    Introduction: Debates on Experience and Empiricism in Nineteenth Century France

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    The lasting effects of the debate over canon-formation during the 1980s affected the whole field of Humanities, which became increasingly engaged in interrogating the origin and function of the Western canon (Gorak 1991; Searle 1990). In philosophy, a great deal of criticism was, as a result, directed at the traditional narrative of seventeenth-and eighteenth-century philosophies—a critique informed by postcolonialism (Park 2013) as well as feminist historiography (Shapiro 2016). D. F. Norton (1981), L. Loeb (1981) and many others1 attempted to demonstrate the weaknesses of the tripartite division between rationalism, empiricism and critical philosophy.2 As time went on, symptoms of dissatisfaction with what has been called the “standard narrative” ( Vanzo 2013) and the “epistemological par-adigm” (Haakonssen 2004, 2006) only increased. Indeed, at present, a consensus has been reached that the narrative of the antagonism between “Continental rationalism” and “British empiricism”, and the consequent Aufhebung provided by “German critical philosophy,” has been unable to make sense of the complexity, variety and dynamics of early modern.Fil: Antoine-Mahut, Delphine. Ecole Normale Supérieure; FranciaFil: Manzo, Silvia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Humanidades y Ciencias Sociales. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación. Instituto de Investigaciones en Humanidades y Ciencias Sociales; Argentin

    XLF and APLF bind Ku80 at two remote sites to ensure DNA repair by non-homologous end joining

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    International audienceThe Ku70-Ku80 (Ku) heterodimer binds rapidly and tightly to the ends of DNA double-strand breaks and recruits factors of the non-homologous end-joining (NHEJ) repair pathway through molecular interactions that remain unclear. We have determined crystal structures of the Ku-binding motifs (KBM) of the NHEJ proteins APLF (A-KBM) and XLF (X-KBM) bound to a Ku-DNA complex. The two KBM motifs bind remote sites of the Ku80 alpha/beta domain. The X-KBM occupies an internal pocket formed by an unprecedented large outward rotation of the Ku80 alpha/beta domain. We observe independent recruitment of the APLF-interacting protein XRCC4 and of XLF to laser-irradiated sites via binding of A- and X-KBMs, respectively, to Ku80. Finally, we show that mutation of the X-KBM and A-KBM binding sites in Ku80 compromises both the efficiency and accuracy of end joining and cellular radiosensitivity. A- and X-KBMs may represent two initial anchor points to build the intricate interaction network required for NHEJ

    Étude pratique des réactifs colorants employés en technique microscopique (travail du laboratoire des cliniques)

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    Thèse : Médecine : Université de Bordeaux : 1900N° d'ordre : 5

    Présentation

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    Caye Pierre, Gontier Thierry. Présentation. In: Revue d'histoire des sciences, tome 59, n°2, 2006. pp. 181-186

    Montaigne

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    Tel un Homère moderne, Montaigne parle en un sens dans ses Essais de tout. Son propos reste cependant en premier lieu celui d'un moraliste, et ce en un double sens : au sens de celui qui scrute les mœurs des hommes et sonde les véritables motifs de leurs actions d'une part ; au sens de celui qui prescrit et impose des normes pour l'agir humain d'autre part. Ces normes, Montaigne ne les trouve pas dans un être - être avec lequel, comme il le dit, " nous n'avons aucune communication " -, mais dans l'immanence même de l'homme, et plus précisément dans la relation que l'esprit humain entretient à son corps. C'est ainsi à travers le détour d'une réflexion sur la nature de l'homme compris dans l'intégralité de sa condition que Montaigne pense ce que pourrait être une prudence des modernes, reposant sur un art de fonder, dans un contexte de chaos politique et moral, voire métaphysique, un ordre stable de la vie humaine. Ce recueil comprend les contributions de Bernard Sève, Philippe Desan, Nicola Panichi, Suzel Mayer, Francis Goyet, Jean Balsamo, Marc Foglia, Thierry Ménissier, Jean-Louis Vieillard-Baron, Emiliano Ferrari, Ali Benmakhlouf, Géralde Nakam, Thierry Gontier et Pierre Magnard
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