278 results match your criteria: "Centre d'etudes de Saclay[Affiliation]"

This Letter presents the first experimental observation of the attractive strong interaction between a proton and a multistrange baryon (hyperon) Ξ^{-}. The result is extracted from two-particle correlations of combined p-Ξ^{-}⊕p[over ¯]-Ξ[over ¯]^{+} pairs measured in p-Pb collisions at sqrt[s_{NN}]=5.02  TeV at the LHC with ALICE.

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The local magnetic structure in the [Fe (Tp)(CN) ] building block was investigated by combining paramagnetic Nuclear Magnetic Resonance (pNMR) spectroscopy and polarized neutron diffraction (PND) with first-principle calculations. The use of the pNMR and PND experimental techniques revealed the extension of spin-density from the metal to the ligands, as well as the different spin mechanisms that take place in the cyanido ligands: Spin-polarization on the carbon atoms and spin-delocalization on the nitrogen atoms. The results of our combined density functional theory (DFT) and multireference calculations were found in good agreement with the PND results and the experimental NMR chemical shifts.

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[RadioTransNet, the French network for preclinical research in oncological radiotherapy].

Cancer Radiother

October 2019

Société française de radiothérapie oncologique, 47, rue de la Colonie, 75013 Paris, France; Département de radiothérapie, GHU Pitié-Salpêtrière-Charles Foix, 47/83, boulevard de l'hôpital, 75013 Paris, France.

The ambition of the RADIOTRANSNET network, launched by the INCa at the end of 2018, is to create a French research consortium dedicated to preclinical radiotherapy to foster scientific and clinical interactions at the interface of radiotherapy and radiobiology, and to identify research priorities dedicated to innovation in radiotherapy. The activities of the network are organized around four major axes that are target definition, normal tissue, combined treatments and dose modelling. Under the supervision of the Scientific Council, headed by a coordinator designated by the SFRO and a co-coordinator designated by the SFPM, three leaders coordinate each axis: a radiation-oncologist, a medical physicist and a biologist, who are responsible for organizing a scientific meeting based on the consensus conference methodology to identify priority issues.

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Simpler free-energy functional of the Debye-Hückel model of fluids and the nonuniqueness of free-energy functionals in the theory of fluids.

Phys Rev E

May 2019

Laboratoire "Interactions, Dynamiques et Lasers", UMR 9222, CEA-CNRS-Université Paris-Saclay, Centre d'Études de Saclay, F-91191 Gif-sur-Yvette Cedex, France.

In previous publications [Piron and Blenski, Phys. Rev. E 94, 062128 (2016)2470-004510.

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A nano-silica consolidant and nano-titania modified tetraethyl-orthosilicate were applied on two building stones, a carbonate and a silicate, by brush, poultice or capillary absorption. Neutron radiography was used to monitor capillary water absorption, and to analyse changes in physical properties caused by heat treatment of specimens for the purposes of artificially ageing and different treatment applications with stone consolidants. Moreover, ultrasonic pulse velocity and gravimetrically determined water absorption were analysed to cross-validate neutron radiography.

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Integrated datasets of normalized brain with functional localization using intra-operative electrical stimulation.

Int J Comput Assist Radiol Surg

December 2019

Faculty of Advanced Techno-Surgery, Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, 8-1 (TWIns) Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.

Purpose: The purpose of this study was to transform brain mapping data into a digitized intra-operative MRI and integrated brain function dataset for predictive glioma surgery considering tumor resection volume, as well as the intra-operative and postoperative complication rates.

Methods: Brain function data were transformed into digitized localizations on a normalized brain using a modified electric stimulus probe after brain mapping. This normalized brain image with functional information was then projected onto individual patient's brain images including predictive brain function data.

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Climate science: Predictable ice ages on a chaotic planet.

Nature

February 2017

Laboratory of Climate and Environmental Sciences, Centre d'Etudes de Saclay, 91191 Gif-sur-Yvette, France.

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Free-energy functional of the Debye-Hückel model of simple fluids.

Phys Rev E

December 2016

Laboratoire "Interactions, Dynamiques et Lasers", UMR 9222, CEA-CNRS-Université Paris-Saclay, Centre d'Études de Saclay, F-91191 Gif-sur-Yvette Cedex, France.

The Debye-Hückel approximation to the free energy of a simple fluid is written as a functional of the pair correlation function. This functional can be seen as the Debye-Hückel equivalent to the functional derived in the hypernetted chain framework by Morita and Hiroike, as well as by Lado. It allows one to obtain the Debye-Hückel integral equation through a minimization with respect to the pair correlation function, leads to the correct form of the internal energy, and fulfills the virial theorem.

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Chirped pulse amplification in an extreme-ultraviolet free-electron laser.

Nat Commun

December 2016

Elettra-Sincrotrone Trieste, Strada Statale 14-km 163,5, 34149 Trieste, Italy.

Chirped pulse amplification in optical lasers is a revolutionary technique, which allows the generation of extremely powerful femtosecond pulses in the infrared and visible spectral ranges. Such pulses are nowadays an indispensable tool for a myriad of applications, both in fundamental and applied research. In recent years, a strong need emerged for light sources producing ultra-short and intense laser-like X-ray pulses, to be used for experiments in a variety of disciplines, ranging from physics and chemistry to biology and material sciences.

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High-order moments of spin-orbit energy in a multielectron configuration.

Phys Rev E

July 2016

Laboratoire "Interactions, Dynamiques et Lasers", UMR 9222, CEA-CNRS-Université Paris-Saclay, Centre d'Études de Saclay, F91191 Gif-sur-Yvette, Cedex, France.

In order to analyze the energy-level distribution in complex ions such as those found in warm dense plasmas, this paper provides values for high-order moments of the spin-orbit energy in a multielectron configuration. Using second-quantization results and standard angular algebra or fully analytical expressions, explicit values are given for moments up to 10th order for the spin-orbit energy. Two analytical methods are proposed, using the uncoupled or coupled orbital and spin angular momenta.

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Single-shot diffraction data from the Mimivirus particle using an X-ray free-electron laser.

Sci Data

August 2016

Department of Cell and Molecular Biology, Laboratory of Molecular Biophysics, Uppsala University, Husargatan 3 (Box 596), SE-751 24 Uppsala, Sweden.

Article Synopsis
  • * A recent study achieved the first 3D reconstruction of a biological object using FEL, focusing on the giant Mimivirus, a large virus measuring 450 nm in diameter.
  • * The dataset from this reconstruction is now available for the scientific community, aimed at fostering algorithm development in single-particle imaging and serving as a benchmark for future research.
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A first principle particle mesh method for solution SAXS of large bio-molecular systems.

J Chem Phys

July 2016

Commissariat à l'Energie Atomique, DRF/IBITECS/SB2SM, Centre d'Etudes de Saclay, 91191 Gif-sur-Yvette Cedex, France.

This paper will show that the solution small angle X-ray scattering (SAXS) intensity of globular and membrane proteins can be efficiently and accurately computed from molecular dynamics trajectories using 3D fast Fourier transforms (FFTs). A suitable particle meshing interpolation, similar to the one used in smooth particle mesh Ewald for electrostatic energies and forces, was combined with a uniform solvent density FFT padding scheme to obtain a convenient SAXS spectral resolution. The CPU time scaling of the method, as a function of system size, is highly favorable and its application to large systems such as solutions of solvated membrane proteins is computationally undemanding.

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Dense arrays of cobalt nanorods as rare-earth free permanent magnets.

Nanoscale

February 2016

Université de Toulouse, Laboratoire de Physique et Chimie des Nano-Objets, UMR 5215 INSA, CNRS, UPS, 135 avenue de Rangueil F-31077 Toulouse cedex 4, France.

We demonstrate in this paper the feasibility to elaborate rare-earth free permanent magnets based on cobalt nanorods assemblies with energy product (BH)max exceeding 150 kJ m(-3). The cobalt rods were prepared by the polyol process and assembled from wet suspensions under a magnetic field. Magnetization loops of dense assemblies with remanence to a saturation of 0.

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Modeling the Self-Aggregation of Small AOT Reverse Micelles from First-Principles.

J Phys Chem Lett

January 2015

Commissariat à l'Energie Atomique, DSV/i-BiTec-S/SB2SM/LBMS, CNRS UMR 8221, Centre d'Etudes de Saclay, 91191 Gif-sur-Yvette Cedex, France.

This Letter is the first attempt at studying the self-aggregation of AOT reverse micelles from first-principles. It focuses on predicting the aggregation number, the radius of gyration, and the hydrodynamic radius of a low water content reverse micelle by theoretical means. We show that molecular dynamics simulation in the μs time range combined with atomistic potentials is capable of reproducing and explaining, to a convenient degree, experimental results on the size and dimensions of reverse micelles of AOT of low water content, [H2O]/[AOT] ≈ 5.

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Magnetic anisotropy, unusual hysteresis and putative "up-up-down" magnetic structure in EuTAl4Si2 (T = Rh and Ir).

Sci Rep

July 2015

CEA, Centre d'Etudes de Saclay, DSM/IRAMIS/Service de Physique de l'Etat Condensé and CNRS UMR 3680, 91191 Gif-sur-Yvette, France.

We present detailed investigations on single crystals of quaternary EuRhAl4Si2 and EuIrAl4Si2. The two compounds order antiferromagnetically at TN1 = 11.7 and 14.

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Corpus callosum area in patients with bipolar disorder with and without psychotic features: an international multicentre study.

J Psychiatry Neurosci

September 2015

From AP-HP, Hôpital H. Mondor - A. Chenevier, DHU PePSY, Pôle de Psychiatrie, Créteil, France (Sarrazin, d'Albis, Daban, Hamdani, Leboyer, Houenou); Université Paris-Est, UMR_S955, UPEC, F-94000, Créteil, France (Sarrazin, Leboyer); Fondation FondaMental, fondation de coopération scientifique, F-94000, Créteil, France (Sarrazin, d'Albis, Daban, Hamdani, Leboyer, Houenou); UNIACT, Neurospin, Commissariat à l'Energie Atomique, Centre d'études de Saclay, Gif sur Yvette (Sarrazin, d'Albis, Houenou); INSERM, U955, Equipe Psychopathologie des maladies psychiatriques, F-94000, Créteil, France (Sarrazin, d'Albis, Daban, Hamdani, Leboyer, Houenou); Clinical Science Institute, National University of Ireland, Galway, Ireland (McDonald); Institute for Psychology Johannes Gutenberg-University of Mainz, Department of Clinical Psychology and Neuropsychology, Mainz, Germany (Linke, Wessa); Department of Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. (Phillips, Versace, Almeida); AP-HP, Hôpital Fernand Widal-Lariboisière, Service de psychiatrie, Paris, France (Delavest); Translational MRI, Department of Imaging and Pathology, KU Leuven and Radiology, University Hospitals Leuven, Belgium (Emsell); UNATI, Neurospin, Commissariat à l'Energie Atomique, Centre d'études de Saclay, Gif sur Yvette, France (Mangin); UNIRS, Neurospin, Commissariat à l'Energie Atomique, Centre d'études de Saclay, Gif sur Yvette, France (Poupon); AP-HP, Centre d'Investigation Clinique et Plateforme de Ressources Biologiques, Hôpitaux Henri Mondor, Créteil, France (Le Dudal).

Background: Previous studies have reported MRI abnormalities of the corpus callosum (CC) in patients with bipolar disorder (BD), although only a few studies have directly compared callosal areas in psychotic versus nonpsychotic patients with this disorder. We sought to compare regional callosal areas in a large international multicentre sample of patients with BD and healthy controls.

Methods: We analyzed anatomic T1 MRI data of patients with BD-I and healthy controls recruited from 4 sites (France, Germany, Ireland and the United States).

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Small-scale dynamo magnetism as the driver for heating the solar atmosphere.

Nature

June 2015

AIM - Unité Mixte de Recherche CEA - CNRS - Université Paris VII, UMR no. 7158, Centre d'Etudes de Saclay, F-91191 Gif sur Yvette Cedex, France.

The long-standing problem of how the solar atmosphere is heated has been addressed by many theoretical studies, which have stressed the relevance of two specific mechanisms, involving magnetic reconnection and waves, as well as the necessity of treating the chromosphere and corona together. But a fully consistent model has not yet been constructed and debate continues, in particular about the possibility of coronal plasma being heated by energetic phenomena observed in the chromosphere. Here we report modelling of the heating of the quiet Sun, in which magnetic fields are generated by a subphotospheric fluid dynamo intrinsically connected to granulation.

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Characterizing and predicting the magnetic environment leading to solar eruptions.

Nature

October 2014

AIM, Unité Mixte de Recherche CEA, CNRS, Université Paris VII, UMR 7158, Centre d'Etudes de Saclay, F-91191 Gif sur Yvette Cedex, France.

The physical mechanism responsible for coronal mass ejections has been uncertain for many years, in large part because of the difficulty of knowing the three-dimensional magnetic field in the low corona. Two possible models have emerged. In the first, a twisted flux rope moves out of equilibrium or becomes unstable, and the subsequent reconnection then powers the ejection.

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The location of the Trp radical and the catalytic function of the [Fe(IV)═O Trp₁₉₁(•+)] intermediate in cytochrome c peroxidase (CcP) are well-established; however, the unambiguous identification of the site(s) for the formation of tyrosyl radical(s) and their possible biological roles remain elusive. We have now performed a systematic investigation of the location and reactivity of the Tyr radical(s) using multifrequency Electron Paramagnetic Resonance (EPR) spectroscopy combined with multiple-site Trp/Tyr mutations in CcP. Two tyrosines, Tyr71 and Tyr236, were identified as those contributing primarily to the EPR spectrum of the tyrosyl radical, recorded at 9 and 285 GHz.

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[Non-medical applications for brain MRI: Ethical considerations].

Encephale

April 2015

Pôle de psychiatrie des hôpitaux universitaires Henri-Mondor, AP-HP, 40, rue de Mesly, 94000 Créteil, France; Inserm unité 955, IMRB, équipe 15 « psychiatrie génétique », 94000 Créteil, France; Fondation FondaMental, 40, rue de Mesly, 94000 Créteil, France; Plateforme de neuro-imagerie NeuroSpin, commissariat à l'energie atomique, centre d'études de Saclay, 91191 Gif-sur-Yvette, France. Electronic address:

Introduction: The recent neuroimaging techniques offer the possibility to better understand complex cognitive processes that are involved in mental disorders and thus have become cornerstone tools for research in psychiatry. The performances of functional magnetic resonance imaging are not limited to medical research and are used in non-medical fields. These recent applications represent new challenges for bioethics.

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Intensity-based image registration using scatter search.

Artif Intell Med

March 2014

NeuroSpin, French Alternative Energies and Atomic Energy Commission, Bâtiment 145, Centre d'études de Saclay, 91191 Gif-sur-Yvette, France; Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, Hôpital Pitié Salpêtrière, Boulevard de l'Hôpital 47, 75013 Paris, France. Electronic address:

Objective: We present a novel intensity-based algorithm for medical image registration (IR).

Methods And Materials: The IR problem is formulated as a continuous optimization task, and our work focuses on the development of the optimization component. Our method is designed over an advanced scatter search template, and it uses a combination of restart and dynamic boundary mechanisms integrated within a multi-resolution strategy.

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Spectroscopic and kinetic investigation of the reactions of peroxyacetic acid with Burkholderia pseudomallei catalase-peroxidase, KatG.

Biochemistry

October 2013

CNRS, Unité de Recherche Mixte CNRS/CEA/Université Paris Sud (UMR 8221), Laboratoire de Bioénergétique, Métalloprotéines et Stress, Centre d'Etudes de Saclay/iBiTec-S, 91191 Gif-sur-Yvette, France.

Catalase-peroxidases or KatGs can utilize organic peroxyacids and peroxides instead of hydrogen peroxide to generate the high-valent ferryl-oxo intermediates involved in the catalase and peroxidase reactions. In the absence of peroxidatic one-electron donors, the ferryl intermediates generated with a low excess (10-fold) of peroxyacetic acid (PAA) slowly decay to the ferric resting state after several minutes, a reaction that is demonstrated in this work by both stopped-flow UV-vis absorption measurements and EPR spectroscopic characterization of Burkholderia pseudomallei KatG (BpKatG). EPR spectroscopy showed that the [Fe(IV)═O Trp330(•+)], [Fe(IV)═O Trp139(•)], and [Fe(IV)═O Trp153(•)] intermediates of the peroxidase-like cycle of BpKatG ( Colin, J.

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Opacity of iron, nickel, and copper plasmas in the x-ray wavelength range: theoretical interpretation of 2p-3d absorption spectra.

Phys Rev E Stat Nonlin Soft Matter Phys

September 2011

CEA, IRAMIS, Service Photons, Atomes et Molécules, Centre d'Études de Saclay, F-91191 Gif-sur-Yvette Cedex, France.

This paper deals with theoretical studies on the 2p-3d absorption in iron, nickel, and copper plasmas related to LULI2000 (Laboratoire pour l'Utilisation des Lasers Intenses, 2000J facility) measurements in which target temperatures were of the order of 20 eV and plasma densities were in the range 0.004-0.01 g/cm(3).

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Optical chemical sensors based on hybrid organic-inorganic sol-gel nanoreactors.

Chem Soc Rev

February 2011

CEA, IRAMIS/SPAM/Laboratoire Francis Perrin, URA 2453, Centre d'Etudes de Saclay, F-91191 Gif-sur-Yvette Cedex, France.

Sol-gel porous materials with tailored or nanostructured cavities have been increasingly used as nanoreactors for the enhancement of reactions between entrapped chemical reactants. The domains of applications issued from these designs and engineering are extremely wide. This tutorial review will focus on one of these domains, in particular on optical chemical sensors, which are the subject of extensive research and development in environment, industry and health.

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We present a study aimed at developing a label-free optical fiber biosensor for detection and quantification of biomolecules in real-time. The biosensor based on a Tilted Fiber Bragg Grating (TFBG) transduces a binding event between the probe and target molecules into a change in the refractive index of the medium surrounding the fiber. This work describes the experimental results obtained with three methods for immobilizing biomolecular probes on a TFBG silica cladding surface.

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