167 results match your criteria: "CNRS-Universite de Poitiers[Affiliation]"

Structural, Contractile and Electrophysiological Adaptations of Cardiomyocytes to Chronic Exercise.

Adv Exp Med Biol

May 2018

Equipe Transferts Ioniques et Rythmicité Cardiaque (TIRC), Lab. Signalisation et Transports Ioniques Membranaires (STIM), ERL CNRS/Université de Poitiers n°7368, Faculté des Sciences Fondamentales et Appliquées, Pôle Biologie Santé Bât B36/B37, 1 rue Georges Bonnet TSA 51106, 86073, Poitiers Cedex 9, France.

Cardiac beneficial effects of chronic exercise is well admitted. These effects mainly studied at the organ and organism integrated levels find their origin in cardiomyocyte adaptation. This chapter try to highlight the main trends of the data related to the different parameters subject to such adaptations.

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Hippopotamidae (Cetartiodactyla, Hippopotamoidea) from Kanapoi, Kenya, and the taxonomic status of the late early Pliocene hippopotamids from the Turkana Basin.

J Hum Evol

March 2020

Centre Français des Études Éthiopiennes, USR 3137, CNRS & Ministère de l'Europe et des Affaires Étrangères, P.O. BOX 5554, Addis Ababa, Ethiopia; Institut de paléoprimatologie et de Paléontologie Humaine: Évolution et Paléoenvironnements, UMR 7262, CNRS & Université de Poitiers, 6 rue M. Brunet, 86073, Poitiers Cedex 9, France. Electronic address:

New hippopotamid specimens recently collected at Kanapoi (ca. 4 Ma) are similar to the taxon previously recognized in this site and referred to aff. Hippopotamus protamphibius.

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This study aims to produce levulinic acid (LA) from paper towel waste in environment-friendly and economically feasible conditions, and evaluate the difference using solid and aqueous Brønsted acids. Direct dehydration of glucose to LA required sufficiently strong Brønsted acidity, where Amberlyst 36 demonstrated rapid production of approximately 30Cmol% of LA in 20min. However, the maximum yield of LA was limited by mass transfer.

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Termites of the genus Reticulitermes are widespread invaders, particularly in urban habitats. Their cryptic and subterranean lifestyle makes them difficult to detect, and we know little about their colony dynamics over time. In this study we examined the persistence of Reticulitermes flavipes (Kollar) colonies in the city of Paris over a period of 15 years.

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Background: Burst fractures represent a significant proportion of fractures of the thoracolumbar junction. The recent advent of minimally invasive techniques has revolutionized the surgical treatment of this type of fracture. However mechanical behaviour and primary stability offered by these solutions have to be proved from experimental validation tests on cadaveric specimens.

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Valorisation of bread waste for hydroxymethylfurfural (HMF) synthesis was examined in dimethyl sulfoxide (DMSO)-, tetrahydrofuran (THF)-, acetonitrile (ACN)-, and acetone-water (1:1v/v), under heating at 140°C with SnCl as the catalyst. The overall rate of the process was the fastest in ACN/HO and acetone/HO, followed by DMSO/HO and THF/HO due to the rate-limiting glucose isomerisation. However, the formation of levulinic acid (via rehydration) and humins (via polymerisation) was more significant in ACN/HO and acetone/HO.

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River biofilm community changes related to pharmaceutical loads emitted by a wastewater treatment plant.

Environ Sci Pollut Res Int

April 2018

UMR CARRTEL, INRA, USMB, 75 avenue de Corzent, 74200, Thonon-les-Bains, France.

Wastewater treatment plants (WWTP) are the main sources of a broad spectrum of pharmaceuticals found in freshwater ecosystems. These pollutants raise environmental health concerns because of their highly bioactive nature and their chronic releases. Despite this, pharmaceuticals' effects on aquatic environments are poorly defined.

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Biomechanical studies that involve normal, injured or stabilized human spines are sometimes difficult to perform on large samples due to limited access to cadaveric human spines and biological variability. Finite element models alleviate these limitations due to the possibility of reusing the same model, whereas cadaveric spines can be damaged during testing, or have their mechanicals behaviour modified by fatigue, permanent deformation or structural failure. Finite element models need to be validated with experimental data to make sure that they represent the complex mechanical and physiological behaviour of normal, injured and stabilized spinal segments.

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Conversion of Cellulose into Amphiphilic Alkyl Glycosides Catalyzed by Aquivion, a Perfluorosulfonic Acid Polymer.

ChemSusChem

September 2017

Institut de Chimie des Milieux et Matériaux de Poitiers, CNRS/Université de Poitiers, 1 rue Marcel Doré, ENSIP, TSA 41105, 86073, Poitiers cedex 9, France.

The perfluorosulfonic acid (PFSA) Aquivion PW98 is an amphiphilic solid superacid which is shown to catalyze the conversion of cellulose into amphiphilic alkyl glycosides (AAGs) in 85 % yield (with 97 % selectivity). The process involves a mechanocatalytic depolymerization of cellulose followed by a direct glycosylation with n-dodecanol. In comparison to H SO and solid acid catalysts commonly employed in cellulose processing, Aquivion PFSA PW98 is not only recyclable but also exhibits superior catalytic performances in terms of yield, selectivity, and reactor productivity.

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Tight control of basal cytosolic Ca concentration is essential for cell survival and to fine-tune Ca-dependent cell functions. A way to control this basal cytosolic Ca concentration is to regulate membrane Ca channels including store-operated Ca channels and secondary messenger-operated channels linked to G-protein-coupled or tyrosine kinase receptor activation. Orai, with or without its reticular STIM partner and Transient Receptor Potential (TRP) proteins, were considered to be the main Ca channels involved.

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Scanning transmission electron microscopy (STEM) was successfully applied to the analysis of silicon nanowires (SiNWs) that were self-assembled during an inductively coupled plasma (ICP) process. The ICP-synthesized SiNWs were found to present a Si-SiO core-shell structure and length varying from ≈100 nm to 2-3 μm. The shorter SiNWs (maximum length ≈300 nm) were generally found to possess a nanoparticle at their tip.

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Synthesis of MAX Phases in the Zr-Ti-Al-C System.

Inorg Chem

March 2017

KU Leuven , Department of Materials Engineering, Kasteelpark Arenberg 44, B-3001 Leuven, Belgium.

This study reports on the synthesis and characterization of MAX phases in the (Zr,Ti)AlC system. The MAX phases were synthesized by reactive hot pressing and pressureless sintering in the 1350-1700 °C temperature range. The produced ceramics contained large fractions of 211 and 312 (n = 1, 2) MAX phases, while strong evidence of a 413 (n = 3) stacking was found.

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Acoustic and streaming velocity components in a resonant waveguide at high acoustic levels.

J Acoust Soc Am

January 2017

Sorbonne Universités, UPMC Univ Paris 06, UFR d'Ingénierie, 4 Place Jussieu, 75252 Paris Cedex 05, LIMSI, CNRS, F-91405 Orsay, France.

Rayleigh streaming is a steady flow generated by the interaction between an acoustic wave and a solid wall, generally assumed to be second order in a Mach number expansion. Acoustic streaming is well known in the case of a stationary plane wave at low amplitude: it has a half-wavelength spatial periodicity and the maximum axial streaming velocity is a quadratic function of the acoustic velocity amplitude at antinode. For higher acoustic levels, additional streaming cells have been observed.

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Redox reactions of inorganic and organic contaminants on manganese oxides have been widely studied. However, these reactions are strongly affected by the presence of natural organic matter (NOM) at the surface of the manganese oxide. Interestingly, the mechanism behind NOM adsorption onto manganese oxides remains unclear.

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The role of the surface groups T (T = OH, O or F) in the chemical bonding in two-dimensional TiCT MXene is directly evidenced combining electron energy-loss spectroscopy in a transmission electron microscope and simulations based on density functional theory. By focusing on the 1s core electrons excitations of the C and (F, O) atoms, the site projected electronic structure is resolved. The Electron Energy-Loss Near Edge Structures (ELNES) at the C-K edge are shown to be sensitive to the chemical nature and the location of the T-groups on the MXene's surface and thereby allow for the characterization of the MXene's functionalization on the nanometre scale.

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Impact of Nonthermal Atmospheric Plasma on the Structure of Cellulose: Access to Soluble Branched Glucans.

Chemistry

November 2016

Institut de Chimie des Milieux et Matériaux de Poitiers, CNRS/Université de Poitiers, ENSIP, 1 rue Marcel Doré, Bat 1, TSA 41105, 86073, Poitiers Cedex 9, France.

We have investigated the effect of non-thermal atmospheric plasma (NTAP) on the structure of microcrystalline cellulose. In particular, by means of different characterization methods, we demonstrate that NTAP promotes the partial cleavage of the β-1,4 glycosidic bond of cellulose leading to the release of short-chain cellodextrins that are reassembled in situ, preferentially at the C6 position, to form branched glucans with either a glucosyl or anhydroglucosyl terminal residue. The ramification of cellulosic chain induced by NTAP yields branched glucans that are soluble in DMSO or in water, thus opening a straightforward access to processable glucans from cellulose.

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Including scattering within the room acoustics diffusion model: An analytical approach.

J Acoust Soc Am

October 2016

Institut PPRIME UPR 3346, CNRS-Université de Poitiers-ENSMA, ENSIP-B 7, 6 rue Marcel Doré, 86073 Poitiers Cedex 9, France.

Over the last 20 years, a statistical acoustic model has been developed to predict the reverberant sound field in buildings. This model is based on the assumption that the propagation of the reverberant sound field follows a transport process and, as an approximation, a diffusion process that can be easily solved numerically. This model, initially designed and validated for rooms with purely diffuse reflections, is extended in the present study to mixed reflections, with a proportion of specular and diffuse reflections defined by a scattering coefficient.

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Being the principal product of photosynthesis, sucrose is involved in many metabolic processes in plants. As magnesium (Mg) is phloem mobile, an inverse relationship between Mg shortage and sugar accumulation in leaves is often observed. Mg deficiency effects on carbohydrate contents and invertase activities were determined in Sulla carnosa Desf.

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We measured the power spectrum and two-point correlation function for the randomly fluctuating free surface on the downstream side of a stationary flow with a maximum Froude number F_{max}≈0.85 reached above a localized obstacle. On such a flow the scattering of incident long wavelength modes is analogous to that responsible for black hole radiation (the Hawking effect).

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Hydrogen oxidation and evolution reactions (HOR and HER) are studied on Pt Ni /C materials synthesized by the bromide anion exchange method. Physicochemical characterization shows that this surfactant-free method enables the preparation of well-dispersed and effective catalysts for the processes involved in the anode of H /O fuel cells (HOR) and the cathode of water electrolyzers (HER). The Pt-based materials are modified with different Ni contents to decrease the amount of costly precious metal in the electrode materials.

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While grazing as a selective factor towards hypsodont dentition on mammals has gained a lot of attention, the importance of fruits and seeds as fallback resources for many browsing ungulates has caught much less attention. Controlled-food experiments, by reducing the dietary range, allow for a direct quantification of the effect of each type of items separately on enamel abrasion. We present the results of a dental microwear texture analysis on 40 ewes clustered into four different controlled diets: clover alone, and then three diets composed of clover together with either barley, corn, or chestnuts.

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Plate-type electrostatic separators are commonly employed for the selective sorting of conductive and non-conductive granular materials. The aim of this work is to identify the optimal operating conditions of such equipment, when employed for separating copper and plastics from either flexible or rigid electric wire wastes. The experiments are performed according to the response surface methodology, on samples composed of either "calibrated" particles, obtained by manually cutting of electric wires at a predefined length (4mm), or actual machine-grinded scraps, characterized by a relatively-wide size distribution (1-4mm).

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Role of Scaffolding Proteins in the Regulation of TRPC-Dependent Calcium Entry.

Adv Exp Med Biol

September 2016

Laboratory STIM, ERL-7368 CNRS-Université de Poitiers, 1, rue Georges Bonnet, Bat. B36, Pôle Biologie-Santé, 86000, Poitiers, France.

Plasma membrane ion channels, and in particular TRPC channels need a specific membrane environment and association with scaffolding, signaling, and cytoskeleton proteins in order to play their important functional role. The molecular composition of TRPC channels is an important factor in determining channel activation mechanisms. TRPC proteins are incorporated in macromolecular complexes including several key Ca(2 +) signaling proteins as well as proteins involved in vesicle trafficking, cytoskeletal interactions, and scaffolding.

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X-Intrinsic Proteins (XIP) were recently identified in a narrow range of plants as a full clade within the aquaporins. These channels reportedly facilitate the transport of a wide range of hydrophobic solutes. The functional roles of XIP in planta remain poorly identified.

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