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42 results on '"Barrat, S."'

3. Identifying causation in hypersensitivity pneumonitis: a British perspective

Author

Barber, CM, Burge, PS, Feary, JR, Parfrey, H, Renzoni, EA, Spencer, LG, Walters, GI, Wiggans, RE, Adamali, H, Babu, S, Barrat, S, Basran, A, Beirne, P, Bianchi, S, Chalmers, G, Chaudhuri, N, Davies, S, Dempsey, O, Eccles, S, Fiddler, C, Foley, N, Forrest, I, Fletcher, S, George, P, Ghani, S, Gibbons, M, Greenstone, M, Hart, S, Hirani, N, Hoyle, J, Hoyles, R, Hutchinson, J, Jenkins, G, Judge, E, Kamath, A, Kokosi, M, Lee, C, Maher, T, Marshall, B, McAndrew, N, Molyneux, P, Morrison, D, O'Hickey, S, Porter, J, Renshaw, S, Sharp, C, Simler, N, Spears, M, Spiers, A, Spinks, K, Spiteri, M, Stenton, C, Sturney, S, Warburton, C, Wiscombe, S, and Woodhead, F

Subjects
Respiratory System, PULMONARY, Bronchoalveolar Lavage, 0302 clinical medicine, Surveys and Questionnaires, Epidemiology, Medicine, EPIDEMIOLOGY, FIBROSIS, 030212 general & internal medicine, Occupational lung disease, Causation, Pulmonologists, Occupational Lung Disease, Interstitial lung disease, Questionnaire, Interstitial Fibrosis, England, GUIDELINE, SURVIVAL, Bronchoalveolar Lavage Fluid, Life Sciences & Biomedicine, Hypersensitivity pneumonitis, Alveolitis, Extrinsic Allergic, Pulmonary and Respiratory Medicine, medicine.medical_specialty, Consensus, ANTIGEN, GB HP Survey Participants, DIAGNOSIS, Interstitial Lung Disease, 03 medical and health sciences, INTERSTITIAL LUNG-DISEASES, Humans, Wales, Science & Technology, IDENTIFICATION, business.industry, Guideline, Allergens, medicine.disease, Pulmonary Alveoli, Scotland, 030228 respiratory system, Family medicine, business, Allergic Alveolitis
Abstract

BackgroundEstablishing whether patients are exposed to a ‘known cause’ is a key element in both the diagnostic assessment and the subsequent management of hypersensitivity pneumonitis (HP).ObjectiveThis study surveyed British interstitial lung disease (ILD) specialists to document current practice and opinion in relation to establishing causation in HP.MethodsBritish ILD consultants (pulmonologists) were invited by email to take part in a structured questionnaire survey, to provide estimates of demographic data relating to their service and to rate their level of agreement with a series of statements. A priori ‘consensus agreement’ was defined as at least 70% of participants replying that they ‘Strongly agree’ or ‘Tend to agree’.Results54 consultants took part in the survey from 27 ILD multidisciplinary teams. Participants estimated that 20% of the patients in their ILD service have HP, and of these, a cause is identifiable in 32% of cases. For patients with confirmed HP, an estimated 40% have had a bronchoalveolar lavage for differential cell counts, and 10% a surgical biopsy. Consensus agreement was reached for 25 of 33 statements relating to causation and either the assessment of unexplained ILD or management of confirmed HP.ConclusionsThis survey has demonstrated that although there is a degree of variation in the diagnostic approach for patients with suspected HP in Britain, there is consensus opinion for some key areas of practice. There are several factors in clinical practice that currently act as potential barriers to identifying the cause for British HP patients.

Published
2019

4. Diamond deposition by chemical vapor deposition process: study of the bias enhanced nucleation step

Author

Barrat, S., Saada, S., Dieguez, I., and Bauer-Grosse, E.

Subjects
Diamonds -- Research, Sedimentation and deposition -- Research, Physics
Abstract

The spatiotemporal evolution of the bias plasma and the diamond coating in relation to the geometrical configuration of the bias device and the nature of the substrate holder was studied. Observations showed that the presence of the plasma was necessary. Based on these, a mechanism to explain the heterogenous deposit and the poor reproducibility was proposed. Results confirmed the proposed model and allowed homogenous diamond films elaborated with reproducible electrical parameters to be allowed.

Published
1998

5. LaFeOxNy perovskite thin films: Nitrogen location and its effect on morphological, optical and structural properties

Author

Haye, E., Bruyère, S., André, E., Boulet, P., Barrat, S., Capon, F., Miska, P., Migot, S., Carteret, C., Coustel, R., Gendarme, C., and Munnik, F.

Subjects
Oxynitride perovskite, Thin film, Nitrogen doping, LaFeO3
Abstract

This paper reports on the first study of chemical, optical, and structural properties of lanthanum ferrite oxynitride thin films deposited by reactive magnetron sputtering. Thin films were deposited in a Ar/O2/N2 mixture as reactive plasma, from two elemental La and Fe targets, at room and high temperature (25 and 800°C). Films deposited at room temperature are amorphous and have been flash annealed to crystallize the perovskite. Oxynitride properties were investigated and compared to oxide films deposited in Ar/O2 gas mixture. All oxide and oxynitride films present an orthorhombic structure. However, nitrogen doping limited to 1-1.5% leads to lattice expansion (4%), bandgap narrowing, a lower electrical resistivity in range [25-350°C] , and modification of Infrared and Raman spectra. Electron Energy Loss Spectroscopy measurements clearly show the presence of two nitrogen sites with an “active” intra-granular nitrogen associated to an enhancement of the physical properties.

Published
2017

6. Inductive Effect of Nd for Ni3+Stabilization in NdNiO3Synthesized by Reactive DC Cosputtering

Author

Boileau, A., Capon, F., Coustel, R., Laffez, P., Barrat, S., and Pierson, J.F.

Abstract

This work focus on the oxidation states of nickel in NdNiO3, Nd2NiO4, and NiOxthin films deposited by reactive magnetron sputtering. Thin films with a high Ni3+content have been reached in the ternary oxides using a soft subsequent annealing in air. In order to understand the presence of Ni3+oxidation state, the present work establishes a comparative study between the NiOxand Nd–Ni–Oxthin films deposited at room temperature in reactive conditions using different oxygen partial pressures. Crystallographic phases have been systematically identified by X-ray diffraction showing crystallized NiOxand amorphous thin films in the case of Ni and Nd cosputtering. The ionization state of Ni ions has been tracked by X-ray photoelectron spectroscopy. Analyses confirm the presence of Ni2+in NiOxfilms whereas Ni3+is systematically observed in Nd–Ni–Oxfilms highlighting the key role of Nd element during the deposition. The electron donor character of Nd3+on Ni3+via O 2p states by an inductive effect is clearly evidenced. This effect is strengthened by a strong difference in electronegativity between the rare earth (Re) and the transition metal (M). This concept is enlarged and faced with other ReMO3perovskites, and their thermodynamic stability is discussed.

Published
2024
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10. Sequential analysis of diamond nucleation on silicon (001) with bias enhanced nucleation using X-ray photoelectron spectroscopy and reflection high energy electron diffraction investigations

Author

Sarrieu, C., Barth, N., Guise, A., Arnault, Jean-Charles, Saada, Samuel, Barrat, S., Bauer-Grosse, E., Scalian [Rennes], Laboratoire des sciences de l'ingénieur, de l'informatique et de l'imagerie (ICube), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Boostec, MERSEN, Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Capteurs Diamant (LCD-LIST), Département Métrologie Instrumentation & Information (DM2I), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
diamond, reflection high-energy electron diffraction (RHEED), [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], bias enhanced nucleation (BEN), [CHIM]Chemical Sciences, X-ray photoelectron spectroscopy (XPS), amorphous carbon, crystalline silicon carbide, diamond nucleation density, Chemical Vapor Deposition (CVD), heteroepitaxy
Abstract

International audience; Diamond synthesis by microwave plasma assisted chemical vapour deposition (MPCVD) with a bias enhanced nucleation (BEN) step constitutes the most efficient method to obtain heteroepitaxy and is also useful to reach high nucleation densities. In this study, sequential reflection high-energy electron diffraction (RHEED) and X-ray photoelectron spectroscopy (XPS) investigations enabled us to highlight the formation of amorphous carbon and crystalline silicon carbide on the surface before diamond growth. By varying the bias voltage, we underlined an optimized value corresponding to a higher quantity of amorphous carbon. This quantity is strongly correlated to the diamond nucleation density. As for the quality of the SiC texture, this seems to be directly linked to bias voltage too: low bias voltages enable us to obtain high oriented 3C-SiC whereas high bias voltages lead to a completely misoriented polycrystalline SiC film.

Published
2009

38. Chemical and structural transformations of silicon submitted to H2 or H2/CH4 microwave plasmas

Author

Barrat, S., Guise, A., Aouni, A., Diani, M., and Bauer-Grosse, E.

Subjects
*SILICON, *SUBSTRATES (Materials science), *DIAMONDS, *MICROWAVE plasmas
Abstract

Abstract: Silicon substrates are often used to synthesize polycrystalline diamond films by microwave plasma assisted chemical vapour deposition technique (MPCVD). In the case of highly oriented diamond films, several steps are employed to carefully prepare the silicon surface (pre-treatment steps), to nucleate diamond crystals (nucleation step) and to thick the film (growth step). In this study, we characterize {100} silicon substrates and diamond released from its silicon substrate by electronic microscopies (TEM and SEM), by Atomic Force Microscopy (AFM) and by X-ray photoelectron spectroscopy (XPS), to follow the substrate transformations after each step, particularly the formation and the evolution of the silicon carbide and to characterise the diamond films grown on the carburised silicon. We show that according to the experimental conditions and the level of surface/gas contamination by carbon and silicon species, isolated islands or continuous β-SiC compound are formed over the silicon surface and can generate defects such as voids or strip structures that influence the subsequent diamond nucleation and growth. [Copyright &y& Elsevier]

Published
2008
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39. Mechanisms of Oxidation of NdNiO3−δThermochromic Thin Films Synthesized by a Two-Step Method in Soft Conditions

Author

Boileau, A., Capon, F., Laffez, P., Barrat, S., Endrino, J. L., Galindo, R. Escobar, Horwat, D., and Pierson, J. F.

Abstract

Considering it is somewhat difficult to crystallize thermochromic nickelates through a soft process, a major challenge in NdNiO3crystallization is the stabilization of the Ni3+oxidation state against Ni2+. The aim of the present work was to understand why a soft annealing is sufficient while an oxygen high pressure (200 bar) is usually considered as required. Thin films of 300 nm have been deposited by reactive magnetron sputtering at room temperature and working pressure of 0.5, 4, and 7 Pa. The oxygen content of as-deposited and annealed films was estimated by Rutherford backscattering spectrometry, whereas the nickel oxidation state evolution was followed by X-ray photoelectron spectroscopy. The measurements showed that the Ni3+state is reached after deposition whatever the deposition pressure but that an oxygen loss occurs during air annealing with a magnitude depending on the deposition pressure. X-ray diffraction measurements, four-point probe electrical measurements, and infrared optical properties vs temperature were consistent with these results. Thin films deposited at 0.5 Pa and annealed in air at 820 K lead to an orthorhombic structure which becomes rhombohedral when the deposition pressure reaches 7 Pa. The oxygen loss causes a deterioration of the electrical resistivity, which was also evidenced by the thermochromic behavior measured using Fourier transform infrared spectroscopy.

Published
2014
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40. Sequential analysis of diamond nucleation on silicon 001 with bias enhanced nucleation using Xray photoelectron spectroscopy and reflection high energy electron diffraction investigations

Author

Sarrieu, C., Barth, N., Guise, A., Arnault, J. C., Saada, S., Barrat, S., and BauerGrosse, E.

Abstract

Diamond synthesis by microwave plasma assisted chemical vapour deposition MPCVD with a bias enhanced nucleation BEN step constitutes the most efficient method to obtain heteroepitaxy and is also useful to reach high nucleation densities. In this study, sequential reflection highenergy electron diffraction RHEED and Xray photoelectron spectroscopy XPS investigations enabled us to highlight the formation of amorphous carbon and crystalline silicon carbide on the surface before diamond growth. By varying the bias voltage, we underlined an optimized value corresponding to a higher quantity of amorphous carbon. This quantity is strongly correlated to the diamond nucleation density. As for the quality of the SiC texture, this seems to be directly linked to bias voltage too: low bias voltages enable us to obtain high oriented 3CSiC whereas high bias voltages lead to a completely misoriented polycrystalline SiC film.

Published
2009
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41. Crystal orientation distribution in highly oriented diamond films investigated by SEM and TEM

Author

Guise, A., Bozzolo, N., Barrat, S., and Bauer-Grosse, E.

Subjects
*ELECTRON microscopes, *SCANNING electron microscopes, *THIN films, *ELECTRON diffraction
Abstract

Abstract: Orientation imaging techniques based on electron backscattering diffraction (EBSD) and convergent beam electron diffraction (CBED) pattern acquisition carried out respectively in the scanning electron microscope (SEM) and in the transmission electron microscope (TEM) were used to characterise the orientation of crystals in two highly oriented diamond (HOD) films with different thicknesses. The substrate surface modification has been also investigated by EBSD. The films were synthesised on Si(100) in a microwave plasma chemical vapor deposition (MPCVD) reactor where nucleation is initiated via an in situ pretreatment consisting in a carburization step followed by a bias enhanced nucleation (BEN). For the thin film EBSD allowed to highlight the presence of alpha-SiC on the silicon substrate as well as to evaluate their epitaxial relationship. The TEM-based system allowed to obtain more accurate misorientation data of the fine grained diamond structure corresponding to the first stages of growth. For the thicker film, EBSD was used to determine the mosaicity at the surface. [Copyright &y& Elsevier]

Published
2006
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42. Growth of highly oriented diamond films by the MPCVD technique using CO–H2, CH4–H2 and CH4–N2–H2 gas mixtures

Author

Choi, I.-H., Weisbecker, P., Barrat, S., and Bauer-Grosse, E.

Subjects
*DIAMONDS, *THIN films, *NUCLEATION, *NITROGEN
Abstract

Highly oriented diamond (HOD) films were deposited on Si (0 0 1) substrates by the microwave plasma assisted chemical vapor deposition technique using the bias enhanced nucleation (BEN) step. The formation of HOD films is often linked to the presence of few parts per million of nitrogen which stabilizes the texture but deteriorates the chemical quality of the film. In this study, we show that carbon monoxide can be used without nitrogen addition to conserve the 〈0 0 1〉 texture and to promote the {1 0 0} facet extension on the top of the diamond film. After a nucleation step carried out by the BEN technique, and after a subsequent growth time limited to 30 min in a CH4/H2 gas mixture avoiding the coalescence step, HOD films were synthesized using CH4/H2, CO/H2 and N2/CH4/H2 gas mixtures for a growth time fixed to 10–14 h. The effect of carbon monoxide or nitrogen on the morphologies and the texture of the diamond films is discussed from the results of scanning electron microscopy and the texture measurements performed by X-ray diffraction. [Copyright &y& Elsevier]

Published
2004
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