1
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Hurley N, Srinivas S, Fang J, Sun M, Hong S, Chien CT, Guo A, Khan TA, Li M, Cotlet M, Moretti F, Bourret E, Radin D, Tsirka SE, Shelly M, Wong SS. Investigation of the photoluminescent properties, scintillation behaviour and toxicological profile of various magnesium tungstate nanoscale motifs. R Soc Open Sci 2022; 9:220994. [PMID: 36483754 PMCID: PMC9727672 DOI: 10.1098/rsos.220994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 10/14/2022] [Indexed: 06/17/2023]
Abstract
We have synthesized several morphologies and crystal structures of MgWO4 using a one-pot hydrothermal method, producing not only monoclinic stars and large nanoparticles but also triclinic wool balls and sub-10 nm nanoparticles. Herein we describe the importance of reaction parameters in demonstrating morphology control of as-prepared MgWO4. Moreover, we correlate structure and composition with the resulting photoluminescence and radioluminescence properties. Specifically, triclinic-phase samples yielded a photoluminescence emission of 421 nm, whereas monoclinic-phase materials gave rise to an emission maximum of 515 nm. The corresponding radioluminescence data were characterized by a broad emission peak, located at 500 nm for all samples. Annealing the wool balls and sub-10 nm particles to transform the crystal structure from a triclinic to a monoclinic phase yielded a radioluminescence (RL) emission signal that was two orders of magnitude greater than that of their unannealed counterparts. Finally, to confirm the practical utility of these materials for biomedical applications, a series of sub-10 nm particles, including as-prepared and annealed samples, were functionalized with biocompatible PEG molecules, and subsequently were found to be readily taken up by various cell lines as well as primary cultured hippocampal neurons with low levels of toxicity, thereby highlighting for the first time the potential of this particular class of metal oxides as viable and readily generated platforms for a range of biomedical applications.
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Affiliation(s)
- Nathaniel Hurley
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400, USA
| | - Sailesh Srinivas
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400, USA
| | - Justin Fang
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400, USA
- Department of Neurobiology, State University of New York at Stony Brook, Stony Brook, NY 11794-5230, USA
| | - Manli Sun
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400, USA
| | - Simon Hong
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400, USA
| | - Chia Te Chien
- Department of Neurobiology, State University of New York at Stony Brook, Stony Brook, NY 11794-5230, USA
| | - Alan Guo
- Department of Neurobiology, State University of New York at Stony Brook, Stony Brook, NY 11794-5230, USA
| | - Tamor A. Khan
- Department of Neurobiology, State University of New York at Stony Brook, Stony Brook, NY 11794-5230, USA
| | - Mingxing Li
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Building 735, Upton, NY 11973, USA
| | - Mircea Cotlet
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Building 735, Upton, NY 11973, USA
| | - Federico Moretti
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Edith Bourret
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Daniel Radin
- Department of Pharmacological Sciences, State University of New York at Stony Brook, Stony Brook, NY 11794-8651, USA
| | - Stella E. Tsirka
- Department of Pharmacological Sciences, State University of New York at Stony Brook, Stony Brook, NY 11794-8651, USA
| | - Maya Shelly
- Department of Neurobiology, State University of New York at Stony Brook, Stony Brook, NY 11794-5230, USA
| | - Stanislaus S. Wong
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400, USA
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2
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Roede ED, Shapovalov K, Moran TJ, Mosberg AB, Yan Z, Bourret E, Cano A, Huey BD, van Helvoort ATJ, Meier D. The Third Dimension of Ferroelectric Domain Walls. Adv Mater 2022; 34:e2202614. [PMID: 35820118 DOI: 10.1002/adma.202202614] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/13/2022] [Indexed: 06/15/2023]
Abstract
Ferroelectric domain walls are quasi-2D systems that show great promise for the development of nonvolatile memory, memristor technology, and electronic components with ultrasmall feature size. Electric fields, for example, can change the domain wall orientation relative to the spontaneous polarization and switch between resistive and conductive states, controlling the electrical current. Being embedded in a 3D material, however, the domain walls are not perfectly flat and can form networks, which leads to complex physical structures. In this work, the importance of the nanoscale structure for the emergent transport properties is demonstrated, studying electronic conduction in the 3D network of neutral and charged domain walls in ErMnO3 . By combining tomographic microscopy techniques and finite element modeling, the contribution of domain walls within the bulk is clarified and the significance of curvature effects for the local conduction is shown down to the nanoscale. The findings provide insights into the propagation of electrical currents in domain wall networks, reveal additional degrees of freedom for their control, and provide quantitative guidelines for the design of domain-wall-based technology.
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Affiliation(s)
- Erik D Roede
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, Trondheim, 7491, Norway
| | - Konstantin Shapovalov
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, 08193, Spain
| | - Thomas J Moran
- Department of Materials Science and Engineering, University of Connecticut, Storrs, CT, 06269, USA
| | - Aleksander B Mosberg
- Department of Physics, NTNU Norwegian University of Science and Technology, Trondheim, 7491, Norway
- SuperSTEM, STFC Daresbury Laboratories, Keckwick Lane, Warrington, WA4 4AD, UK
| | - Zewu Yan
- Department of Physics, ETH Zurich, Zürich, 8093, Switzerland
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Edith Bourret
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Andres Cano
- Universite Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France
| | - Bryan D Huey
- Department of Materials Science and Engineering, University of Connecticut, Storrs, CT, 06269, USA
| | | | - Dennis Meier
- Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, Trondheim, 7491, Norway
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3
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Schultheiß J, Lysne E, Puntigam L, Schaab J, Bourret E, Yan Z, Krohns S, Meier D. Charged Ferroelectric Domain Walls for Deterministic ac Signal Control at the Nanoscale. Nano Lett 2021; 21:9560-9566. [PMID: 34734722 PMCID: PMC8631726 DOI: 10.1021/acs.nanolett.1c03182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 10/21/2021] [Indexed: 06/13/2023]
Abstract
The direct current (dc) conductivity and emergent functionalities at ferroelectric domain walls are closely linked to the local polarization charges. Depending on the charge state, the walls can exhibit unusual dc conduction ranging from insulating to metallic-like, which is leveraged in domain-wall-based memory, multilevel data storage, and synaptic devices. In contrast to the functional dc behaviors at charged walls, their response to alternating currents (ac) remains to be resolved. Here, we reveal ac characteristics at positively and negatively charged walls in ErMnO3, distinctly different from the response of the surrounding domains. By combining voltage-dependent spectroscopic measurements on macroscopic and local scales, we demonstrate a pronounced nonlinear response at the electrode-wall junction, which correlates with the domain-wall charge state. The dependence on the ac drive voltage enables reversible switching between uni- and bipolar output signals, providing conceptually new opportunities for the application of charged walls as functional nanoelements in ac circuitry.
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Affiliation(s)
- Jan Schultheiß
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), 7034, Trondheim, Norway
| | - Erik Lysne
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), 7034, Trondheim, Norway
| | - Lukas Puntigam
- Experimental
Physics V, University of Augsburg, 86159, Augsburg, Germany
| | - Jakob Schaab
- Department
of Materials, ETH Zurich, 8093, Zurich, Switzerland
| | - Edith Bourret
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Zewu Yan
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Department
of Physics, ETH Zurich, 8093, Zurich, Switzerland
| | - Stephan Krohns
- Experimental
Physics V, University of Augsburg, 86159, Augsburg, Germany
| | - Dennis Meier
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), 7034, Trondheim, Norway
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4
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Evans DM, Holstad TS, Mosberg AB, Småbråten DR, Vullum PE, Dadlani AL, Shapovalov K, Yan Z, Bourret E, Gao D, Akola J, Torgersen J, van Helvoort ATJ, Selbach SM, Meier D. Publisher Correction: Conductivity control via minimally invasive anti-Frenkel defects in a functional oxide. Nat Mater 2021; 20:711. [PMID: 33603189 DOI: 10.1038/s41563-021-00956-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Affiliation(s)
- Donald M Evans
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
| | - Theodor S Holstad
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Aleksander B Mosberg
- Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Didrik R Småbråten
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | | | - Anup L Dadlani
- Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Konstantin Shapovalov
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, Spain
| | - Zewu Yan
- Department of Physics, ETH Zurich, Zürich, Switzerland
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Edith Bourret
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - David Gao
- Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Nanolayers Research Computing Ltd, London, UK
| | - Jaakko Akola
- Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Computational Physics Laboratory, Tampere University, Tampere, Finland
| | - Jan Torgersen
- Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | | | - Sverre M Selbach
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Dennis Meier
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
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5
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Evans DM, Småbråten DR, Holstad TS, Vullum PE, Mosberg AB, Yan Z, Bourret E, van Helvoort ATJ, Selbach SM, Meier D. Observation of Electric-Field-Induced Structural Dislocations in a Ferroelectric Oxide. Nano Lett 2021; 21:3386-3392. [PMID: 33861614 PMCID: PMC8155316 DOI: 10.1021/acs.nanolett.0c04816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/28/2021] [Indexed: 06/12/2023]
Abstract
Dislocations are 1D topological defects with emergent electronic properties. Their low dimensionality and unique properties make them excellent candidates for innovative device concepts, ranging from dislocation-based neuromorphic memory to light emission from diodes. To date, dislocations are created in materials during synthesis via strain fields or flash sintering or retrospectively via deformation, for example, (nano)-indentation, limiting the technological possibilities. In this work, we demonstrate the creation of dislocations in the ferroelectric semiconductor Er(Mn,Ti)O3 with nanoscale spatial precision using electric fields. By combining high-resolution imaging techniques and density functional theory calculations, direct images of the dislocations are collected, and their impact on the local electric transport behavior is studied. Our approach enables local property control via dislocations without the need for external macroscopic strain fields, expanding the application opportunities into the realm of electric-field-driven phenomena.
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Affiliation(s)
- Donald M. Evans
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Didrik René Småbråten
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Theodor S. Holstad
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | | | - Aleksander B. Mosberg
- Department
of Physics, Norwegian University of Science
and Technology (NTNU), 7491 Trondheim, Norway
| | - Zewu Yan
- Department
of Physics, ETH Zürich, 8093 Zürich, Switzerland
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Edith Bourret
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | | | - Sverre M. Selbach
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Dennis Meier
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), 7491 Trondheim, Norway
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6
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Evans DM, Holstad TS, Mosberg AB, Småbråten DR, Vullum PE, Dadlani AL, Shapovalov K, Yan Z, Bourret E, Gao D, Akola J, Torgersen J, van Helvoort ATJ, Selbach SM, Meier D. Conductivity control via minimally invasive anti-Frenkel defects in a functional oxide. Nat Mater 2020; 19:1195-1200. [PMID: 32807925 DOI: 10.1038/s41563-020-0765-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
Utilizing quantum effects in complex oxides, such as magnetism, multiferroicity and superconductivity, requires atomic-level control of the material's structure and composition. In contrast, the continuous conductivity changes that enable artificial oxide-based synapses and multiconfigurational devices are driven by redox reactions and domain reconfigurations, which entail long-range ionic migration and changes in stoichiometry or structure. Although both concepts hold great technological potential, combined applications seem difficult due to the mutually exclusive requirements. Here we demonstrate a route to overcome this limitation by controlling the conductivity in the functional oxide hexagonal Er(Mn,Ti)O3 by using conductive atomic force microscopy to generate electric-field induced anti-Frenkel defects, that is, charge-neutral interstitial-vacancy pairs. These defects are generated with nanoscale spatial precision to locally enhance the electronic hopping conductivity by orders of magnitude without disturbing the ferroelectric order. We explain the non-volatile effects using density functional theory and discuss its universality, suggesting an alternative dimension to functional oxides and the development of multifunctional devices for next-generation nanotechnology.
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Affiliation(s)
- Donald M Evans
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
| | - Theodor S Holstad
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Aleksander B Mosberg
- Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Didrik R Småbråten
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | | | - Anup L Dadlani
- Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Konstantin Shapovalov
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, Spain
| | - Zewu Yan
- Department of Physics, ETH Zurich, Zürich, Switzerland
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Edith Bourret
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - David Gao
- Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Nanolayers Research Computing Ltd, London, UK
| | - Jaakko Akola
- Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Computational Physics Laboratory, Tampere University, Tampere, Finland
| | - Jan Torgersen
- Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | | | - Sverre M Selbach
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Dennis Meier
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
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7
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Evans DM, Holstad TS, Mosberg AB, Småbråten DR, Vullum PE, Dadlani AL, Shapovalov K, Yan Z, Bourret E, Gao D, Akola J, Torgersen J, van Helvoort ATJ, Selbach SM, Meier D. Publisher Correction: Conductivity control via minimally invasive anti-Frenkel defects in a functional oxide. Nat Mater 2020; 19:1254. [PMID: 32929253 DOI: 10.1038/s41563-020-00823-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Affiliation(s)
- Donald M Evans
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
| | - Theodor S Holstad
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Aleksander B Mosberg
- Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Didrik R Småbråten
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | | | - Anup L Dadlani
- Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Konstantin Shapovalov
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, Spain
| | - Zewu Yan
- Department of Physics, ETH Zurich, Zürich, Switzerland
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Edith Bourret
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - David Gao
- Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Nanolayers Research Computing Ltd, London, UK
| | - Jaakko Akola
- Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Computational Physics Laboratory, Tampere University, Tampere, Finland
| | - Jan Torgersen
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, Spain
| | | | - Sverre M Selbach
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Dennis Meier
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
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8
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Yuan D, Moretti F, Perrodin D, Bizarri G, Shalapska T, Dujardin C, Bourret E. Modified floating-zone crystal growth of Mg4Ta2O9 and its scintillation performance. CrystEngComm 2020. [DOI: 10.1039/d0ce00388c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rods of single crystal MgTaO9 were produced free of macroscopic defects and their scintillation properties including afterglow were measured. The compound characteristics make it a candidate for high energy X-ray radiography applications.
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Affiliation(s)
- Dongsheng Yuan
- Materials Sciences Division and Life Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Federico Moretti
- Materials Sciences Division and Life Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Didier Perrodin
- Materials Sciences Division and Life Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Gregory Bizarri
- Materials Sciences Division and Life Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Tetiana Shalapska
- Materials Sciences Division and Life Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Christophe Dujardin
- Université de Lyon
- Université Claude Bernard Lyon 1
- CNRS
- Institut Lumière Matière UMR 5306
- F-69622 Villeurbanne
| | - Edith Bourret
- Materials Sciences Division and Life Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
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9
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Schaab J, Skjærvø SH, Krohns S, Dai X, Holtz ME, Cano A, Lilienblum M, Yan Z, Bourret E, Muller DA, Fiebig M, Selbach SM, Meier D. Electrical half-wave rectification at ferroelectric domain walls. Nat Nanotechnol 2018; 13:1028-1034. [PMID: 30201990 DOI: 10.1038/s41565-018-0253-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 08/02/2018] [Indexed: 06/08/2023]
Abstract
Domain walls in ferroelectric semiconductors show promise as multifunctional two-dimensional elements for next-generation nanotechnology. Electric fields, for example, can control the direct-current resistance and reversibly switch between insulating and conductive domain-wall states, enabling elementary electronic devices such as gates and transistors. To facilitate electrical signal processing and transformation at the domain-wall level, however, an expansion into the realm of alternating-current technology is required. Here, we demonstrate diode-like alternating-to-direct current conversion based on neutral ferroelectric domain walls in ErMnO3. By combining scanning probe and dielectric spectroscopy, we show that the rectification occurs at the tip-wall contact for frequencies at which the walls are effectively pinned. Using density functional theory, we attribute the responsible transport behaviour at the neutral walls to an accumulation of oxygen defects. The practical frequency regime and magnitude of the direct current output are controlled by the bulk conductivity, establishing electrode-wall junctions as versatile atomic-scale diodes.
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Affiliation(s)
- Jakob Schaab
- Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Sandra H Skjærvø
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Stephan Krohns
- Experimental Physics V, University of Augsburg, Augsburg, Germany
| | - Xiaoyu Dai
- Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Megan E Holtz
- School of Applied and Engineering Physics, Department of Physics, Cornell University, Ithaca, NY, USA
| | - Andrés Cano
- Department of Materials, ETH Zurich, Zurich, Switzerland
- Institut Néel, CNRS & University Grenoble Alpes, Grenoble, France
| | | | - Zewu Yan
- Department of Physics, ETH Zurich, Zurich, Switzerland
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Edith Bourret
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - David A Muller
- School of Applied and Engineering Physics, Department of Physics, Cornell University, Ithaca, NY, USA
- Kavli Institute at Cornell for Nanoscale Science Cornell University, Ithaca, NY, USA
| | - Manfred Fiebig
- Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Sverre M Selbach
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Dennis Meier
- Department of Materials, ETH Zurich, Zurich, Switzerland.
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
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10
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Holtz ME, Shapovalov K, Mundy JA, Chang CS, Yan Z, Bourret E, Muller DA, Meier D, Cano A. Topological Defects in Hexagonal Manganites: Inner Structure and Emergent Electrostatics. Nano Lett 2017; 17:5883-5890. [PMID: 28872318 DOI: 10.1021/acs.nanolett.7b01288] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Diverse topological defects arise in hexagonal manganites, such as ferroelectric vortices, as well as neutral and charged domain walls. The topological defects are intriguing because their low symmetry enables unusual couplings between structural, charge, and spin degrees of freedom, holding great potential for novel types of functional 2D and 1D systems. Despite the considerable advances in analyzing the different topological defects in hexagonal manganites, the understanding of their key intrinsic properties is still rather limited and disconnected. In particular, a rapidly increasing number of structural variants is reported without clarifying their relation, leading to a zoo of seemingly unrelated topological textures. Here, we combine picometer-precise scanning-transmission-electron microscopy with Landau theory modeling to clarify the inner structure of topological defects in Er1-xZrxMnO3. By performing a comprehensive parametrization of the inner atomic defect structure, we demonstrate that one primary length scale drives the morphology of both vortices and domain walls. Our findings lead to a unifying general picture of this type of structural topological defects. We further derive novel fundamental and universal properties, such as unusual bound-charge distributions and electrostatics at the ferroelectric vortex cores with emergent U(1) symmetry.
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Affiliation(s)
| | | | - Julia A Mundy
- Department of Material Science and Engineering, University of California, Berkeley , Berkeley, California 94720, United States
| | | | - Zewu Yan
- Department of Physics, ETH Zürich , CH-8093 Zurich, Switzerland
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Edith Bourret
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - David A Muller
- Kavli Institute at Cornell for Nanoscale Science , Ithaca, New York 14853, United States
| | - Dennis Meier
- Department of Materials Science and Engineering, Norwegian University of Science and Technology , 7491 Trondheim, Norway
| | - Andrés Cano
- CNRS, Université de Bordeaux, ICMCB , UPR 9048, 33600 Pessac, France
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11
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Mundy JA, Schaab J, Kumagai Y, Cano A, Stengel M, Krug IP, Gottlob DM, Dog Anay H, Holtz ME, Held R, Yan Z, Bourret E, Schneider CM, Schlom DG, Muller DA, Ramesh R, Spaldin NA, Meier D. Functional electronic inversion layers at ferroelectric domain walls. Nat Mater 2017; 16:622-627. [PMID: 28319611 DOI: 10.1038/nmat4878] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 02/06/2017] [Indexed: 06/06/2023]
Abstract
Ferroelectric domain walls hold great promise as functional two-dimensional materials because of their unusual electronic properties. Particularly intriguing are the so-called charged walls where a polarity mismatch causes local, diverging electrostatic potentials requiring charge compensation and hence a change in the electronic structure. These walls can exhibit significantly enhanced conductivity and serve as a circuit path. The development of all-domain-wall devices, however, also requires walls with controllable output to emulate electronic nano-components such as diodes and transistors. Here we demonstrate electric-field control of the electronic transport at ferroelectric domain walls. We reversibly switch from resistive to conductive behaviour at charged walls in semiconducting ErMnO3. We relate the transition to the formation-and eventual activation-of an inversion layer that acts as the channel for the charge transport. The findings provide new insight into the domain-wall physics in ferroelectrics and foreshadow the possibility to design elementary digital devices for all-domain-wall circuitry.
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Affiliation(s)
- J A Mundy
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - J Schaab
- Department of Materials, ETH Zurich, 8093 Zürich, Switzerland
| | - Y Kumagai
- Department of Materials, ETH Zurich, 8093 Zürich, Switzerland
| | - A Cano
- CNRS, Université de Bordeaux, ICMCB, UPR 9048, 33600 Pessac, France
| | - M Stengel
- ICREA-Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Spain
| | - I P Krug
- Institut für Optik und Atomare Physik, TU Berlin, 10623 Berlin, Germany
| | - D M Gottlob
- Peter Grünberg Institute (PGI-6), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - H Dog Anay
- Peter Grünberg Institute (PGI-6), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - M E Holtz
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - R Held
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - Z Yan
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, ETH Zurich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - E Bourret
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - C M Schneider
- Peter Grünberg Institute (PGI-6), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - D G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
| | - D A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
| | - R Ramesh
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Materials Science and Engineering and Department of Physics, UC Berkeley, Berkeley, California 94720, USA
| | - N A Spaldin
- Department of Materials, ETH Zurich, 8093 Zürich, Switzerland
| | - D Meier
- Department of Materials, ETH Zurich, 8093 Zürich, Switzerland
- Department of Materials Science and Engineering, Norwegian University of Science and Technology, 7491 Trondheim, Norway
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Reis RD, Yang H, Ophus C, Shalapska T, Bizarri G, Perrodin D, Ercius P, Ciston J, Bourret E, Dahmen U. Symmetry group determination and direct imaging of all-inorganic halide perovskites CsPbBr 3−x
Cl
x
. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s0108767317097860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Ennouri M, Bourret E, Baklouti S, Damak K, Rebaï A, Attia H. Étude rhéologique des jus de figue de Barbarie (Opuntia sp.) microfiltrés. ACTA ACUST UNITED AC 2006. [DOI: 10.3166/sda.26.337-348] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Marinho-Soriano E, Bourret E. Polysaccharides from the red seaweed Gracilaria dura (Gracilariales, Rhodophyta). Bioresour Technol 2005; 96:379-382. [PMID: 15474941 DOI: 10.1016/j.biortech.2004.04.012] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2003] [Revised: 02/27/2004] [Accepted: 04/18/2004] [Indexed: 05/24/2023]
Abstract
The yield and physical and chemical properties of agars from Gracilaria dura (C. Agardh) J. Agardh, harvested in Thau lagoon (Mediterranean sea, France), were investigated. The agar yield ranged from 32% to 35%. Gel strength of agar ranged from 263 to 600 g cm(-2), with the maximum observed in October. A positive correlation was found between agar yield and gel strength (r = 0.82; P < 0.01). The gelling temperature followed the same pattern of gel strength and also showed higher value in October (43 degrees C). The nitrogen content varied from 1.04+/-0.60% (June) to 4.70+/-0.01% (October). A positive correlation was noted between nitrogen content and gel strength (r = 0.77; P < 0.05). The 3,6-anhydrogalactose content ranged from 0.70 to 0.84 and showed monthly significant differences (P < 0.05). There was a positive correlation between 3,6-anhydrogalactose content and gel strength. The values of sulfate content were relatively constant during the studied period and no significant differences were observed. The relative high gel strength indicates that this species may be considered as source of agar for commercial use.
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Affiliation(s)
- E Marinho-Soriano
- Departamento de Oceanografia e Limnologia, Laboratório de Macroalgas, Universidade Federal do Rio Grande do Norte, Centro de Biociencias, Praia de Mãe Luiza s/n 59014-100, Natal, RN, Brazil.
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Marinho-Soriano E, Bourret E. Effects of season on the yield and quality of agar from Gracilaria species (Gracilariaceae, Rhodophyta). Bioresour Technol 2003; 90:329-333. [PMID: 14575957 DOI: 10.1016/s0960-8524(03)00112-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The effect of season on yield and physical properties of agars extracted from Gracia gracilis and G. bursa-pastoris were determined. The agar yield from G. gracilis was maximum during spring (30%) and minimum during autumn (19%). In G. bursa-pastoris, the agar yield was greatest in summer (36%) and lowest in winter (23%). Agar yield from G. bursa-pastoris was positively correlated with temperature (r=0.94; P<0.01) and salinity (r=0.97; P<0.01) and negatively with nitrogen content (r=-0.93; P<0.01). Agar gel strengths fluctuated from 229 to 828 gcm(-2) and 23 to 168 gcm(-2) for G. gracilis and G. bursa-pastoris, respectively. The gelling temperature showed significant seasonal variation for both species. Chemical analysis of agar from the two seaweeds indicated variation in 3,6-anhydrogalactose and sulfate content (P<0.01). Furthermore, there was an inverse correlation between the two chemical variables. In general, agar extracted from G. gracilis possessed better qualities than agar extracted from G. bursa-pastoris and can be considered a candidate for industrial use.
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Affiliation(s)
- E Marinho-Soriano
- Departamento de Oceanografia e Limnologia, Laboratório de Macroalgas, UFRN, Praia de Mãe Luiza s/n 59014-100, RN, Natal, Brazil.
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Abstract
An experimental method based on the controlled chymosin-induced kappa-casein hydrolysis of milk was proposed to modify micellar reactivity. Milk samples with a degree of kappa-casein hydrolysis of 19, 35, and 51% were obtained. The physicochemical properties of partially converted casein micelles were determined. The net negative charge of casein micelles was reduced with increasing degree of kappa-casein hydrolysis and a small but significant decrease in hydrodynamic diameter and micellar hydration were noted. Dynamic low amplitude oscillatory rheology was used to monitor the rheological properties of acid milk gels (GDL) made with partially chymosin-hydrolyzed milks in comparison with those of strictly acid and rennet gels. An increase in the gelation pH value was observed with increasing the degree of kappa-casein hydrolysis. The moduli values (G' and G'') reached 2 h after the point of gel were, for all degrees of hydrolysis tested, significantly higher than those of strictly rennet and acid gels. Comparison of changes in delta G'/delta t with time indicated differences in gel formation that could be related to the increased values of G' obtained for acid gel made with chymosin-treated milk. At a given time after gelation (2 h), increasing the degree of kappa-casein hydrolysis in milk led also to an increase in the loss tangent and the serum holding capacity of acid milk gels suggesting a correlation between these two parameters.
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Affiliation(s)
- E Gastaldi
- Laboratoire de Génie des Procédés et Sciences des Aliments, Université Montpellier II, 34095 Montpellier Cedex 05, France.
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Abstract
BACKGROUND Improperly performed skin prick tests (SPT) can lead to wrong allergy diagnosis and incorrect treatment. To overcome false-positive results it is recommended to change the puncture device between each test, although very few studies have examined the real drawbacks (false-positives) and advantages (time and cost savings) of using only one device. METHODS Two groups of 20 patients with rhinitis or asthma, sensitized to either house-dust mites or grass pollens, had successive serial SPT to 9% codeine phosphate and the relevant allergen using the same needle or lancet, wiped between each test. RESULTS With both the needle and the lancet, there were 12.5-67.5% false-positive results using the house-dust mite or grass pollen allergen extracts, respectively. There were no false-positive results with the 9% codeine phosphate. CONCLUSIONS Our study shows that this technique is not reliable as it provoked an unacceptable number of false-positive results.
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Affiliation(s)
- V Piette
- Maladies Respiratoires, INSERM U454-IFR3, Hôpital Arnaud de Villeneuve, CHU de Montpellier, France
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Ferguson-Paré M, Bourret E, Bernick L, Buchanan D, Cabico L, King B, Rivera TM. Best practices in the care of elderly persons in hospital. Hosp Q 2001; 3:30-7. [PMID: 11482267 DOI: 10.12927/hcq..16541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Eouani C, Piccerelle P, Prinderre P, Bourret E, Joachim J. In-vitro comparative study of buccal mucoadhesive performance of different polymeric films. Eur J Pharm Biopharm 2001; 52:45-55. [PMID: 11438423 DOI: 10.1016/s0939-6411(01)00146-1] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A comparison of the buccal mucoadhesive performance of different polymeric films was carried out using texture analyzer TA-XT2i. A large range of putative polymers differing in their chemical nature, molecular structure as well as hydration status was used. The used polymeric films were classified in rank order of buccal mucoadhesive performance, namely carbopol 971P>polycarbophil>Carrrageenan type lambda > Sodium carboxymethylcellulose. Swelling state as well as tensile strength of the used polymeric films was used as measuring parameters of mucoadhesive interaction. These two approaches gave two opposite orders of performance between CMC and Carrrageenan type lambda after a contact time of 15 min. However the measurement of the viscoelastic moduli of the hydrogels gave the same ranking order of mucoadhesive performance after the same contact time. In reference to the previous works, we noted the importance of the molecular weight, the density of charges, the composition of which the chains of molecules are capable to arrange themselves in a network like form, thus those which are characterized by a tan delta<1 (i.e network formation), are those which develop the best synergism with the mucus because of the reinforcement of an established link. The goal of this study is to assess the buccal mucoadhesive performance aiming to optimize the design of drug delivery via buccal mucoadhesive polymeric films
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Affiliation(s)
- C Eouani
- Laboratory of Galenic, Industrial and Cosmetological Pharmacy, University of the Mediterranean, 27 Boulevard Jean-Moulin, 13385 Marseille Cedex 5, France
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Gordon M, Turner L, Bourret E. Addressing ethical issues in geriatrics and long-term care: ethics education at the Baycrest Centre for Geriatric Care. Med Law 2000; 19:475-491. [PMID: 11143884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An innovative program in ethics education exists at Baycrest Centre for Geriatric Care. This program can serve as a helpful model for long-term care and geriatric care facilities seeking to implement formal training programs in bioethics. Various aspects of the ethics education program are examined. In addition to describing the role of the ethics committee and research ethics board, consideration is given to case consultations, ethics rounds, the training of junior physicians and medical students, grand rounds and the planning of conferences and guest lectures. With regard to educational content in bioethics, health law, professional guidelines and the principlist approach of Beauchamp and Childress are used to explore the ethical dimensions of particular cases. Given the clinical context of the educational initiatives, the pedagogical approach is predominately case-based. While the bioethics literature emphasizes the patient-physician relationship, ethics education at Baycrest recognizes the importance of multiple professions. Physicians, nurses, social workers, speech pathologists, nutritionists and other health care providers are involved in ethical deliberation and education.
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Affiliation(s)
- M Gordon
- Baycrest Centre for Geriatric Care, Toronto, Ontario, Canada
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Ratsimbazafy V, Bourret E, Duclos R, Brossard C. Rheological behavior of drug suspensions in Gelucire mixtures and proxyphylline release from matrix hard gelatin capsules. Eur J Pharm Biopharm 1999; 48:247-52. [PMID: 10612036 DOI: 10.1016/s0939-6411(99)00042-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Mixtures of Gelucires 50/02 and 50/13 showing different hydrophilic-lipophilic balances (HLB) and of proxyphylline were used to prepare suspensions at a concentration of 25% and to manufacture extended release hard gelatin capsules by cooling. The rheological behaviors of Gelucire mixtures with and without drug were determined by adjustment of the rheograms to the Ostwald power-law and by statistical assessment of the flow index. Pure Gelucire mixtures were very slightly shear thickening whereas proxyphylline suspensions had a thixotropic shear thinning behavior. These rheological behaviors can be explained by the chemical composition and by the ratio of the two Gelucires used. Extended release of proxyphylline was obtained with all these mixtures. Drug release increased with Gelucire mixture HLB owing to higher erosion. A viscosity-release relationship was found and allowed, with these two Gelucires of extreme HLB and viscosities, to define the formulations which will give an optimal drug release, by the determination of their suspension viscosity. Modeling of dissolution kinetics has generally shown the predominance of surface erosion of the plugs relative to drug diffusion inside the matrix. This was confirmed by the better linearization of percentage released, according to Hixson-Crowell as compared with Higuchi.
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Affiliation(s)
- V Ratsimbazafy
- Laboratory of Pharmaceutical Technology, Faculty of Pharmacy, University of Limoges, France
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Abstract
Three polyol behenates with similar melting points (MP) and different hydrophilic-lipophilic balances (HLB) were studied (MP/HLB: 70/02, 63/05 and 57/13). After melting at MP+30 degrees C, the rheological behaviour of behenates was determined by adjustment of the rheograms to the Ostwald power-law and by statistical assessment of the flow index. Behenates showed slight shear thickening. This shear thickening increased when HLB of behenates decreased. This behaviour accounted for a reorganization of the particles under the shear, which became easier when the proportion of the polyethylene glycol chains in the wax decreased. Proxyphylline was used to prepare suspensions at a concentration of 25% in the melted behenates, and to manufacture monolithic capsules by cooling. The suspensions had a shear-thinning behaviour with or without thixotropy. Colloidal particles and aggregates formed in these suspensions directly influenced the rheological properties, as observation of solidified suspensions by scanning electron microscopy confirmed. Extended release of proxyphylline was obtained with the three waxes. Behenates 63/05 and 70/02 gave inert matrices and released drug very slowly. Hydrodispersible behenate 57/13 swelled and made up a kind of hydrophilic matrix that released proxyphylline more quickly, due to slight erosion. In the three cases, the release mechanism was basically diffusional in nature.
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Affiliation(s)
- R Duclos
- Laboratory of Pharmaceutical Technology, Faculty of Medicine-Pharmacy, 76803, Rouen, France
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Abstract
The theophylline derivatives, etofylline, diprophylline and proxyphylline, which exhibit increasing aqueous solubility, were used to prepare suspensions in seven saturated polyglycolyzed glycerides (Gelucires) characterized by their rising hydrophilic-lipophilic balance (HLB). Drug concentration was set at 25% w/w and the production temperature was set at the Gelucire melting point plus 30 degrees C in order to obtain suitable suspensions. Various formulation factors were studied. Ostwald flow indices revealed that the suspensions had a thixotropic shear-thinning behaviour and a relative viscosity which increased as drug aqueous solubility rose and Gelucire HLB decreased. These rheological properties could be explained by the chemical composition of Gelucires and drugs used. A microstructure was proposed for the liquid suspension such that colloidal particles and aggregates formed in these suspensions directly influenced the observed rheological properties. Observation of solidified suspensions by scanning electron microscopy confirmed this hypothesis. Moreover, a correlation between the relative viscosity of drug suspensions on the one hand and drug concentration, drug solubility and Gelucire HLB on the other allowed for the calculation of the required concentration of each theophylline derivative in each Gelucire to obtain a given viscosity.
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Affiliation(s)
- V Ratsimbazafy
- Laboratory of Pharmaceutical Technology, Faculty of Pharmacy, Limoges, France
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Abstract
Seven saturated polyglycolysed glycerides (Gelucires) of melting points varying from 42 to 53 degrees C and hydrophilic-lipophilic balance values from 2 to 14 were selected. Their rheological behaviour was determined by adjustment of the flow curves to the Ostwald power-law and by statistical assessment of the flow index. The flow of Gelucires was slightly shear thickening. This shear thickening rose when the temperature and the lipophilic specificity of the Gelucire increased. This behaviour accounted for a reorganization of the particles under the shear which became easier when the temperature increased and when the degree of condensation of the polyethylene glycol chains decreased with lipophilicity of the Gelucires.
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Affiliation(s)
- E Bourret
- Laboratory of Pharmaceutical Technology, Faculty of Pharmacy, Limoges, France
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Piszkiewicz D, Thomas W, Lieu M, Cabradilla CD, Andrews J, Kim J, Bourret E, McDougal JS, Cort SP. Heat inactivation of human immunodeficiency virus in lyophilized anti-inhibitor coagulant complex (Autoplex). Thromb Res 1986; 44:701-7. [PMID: 3492776 DOI: 10.1016/0049-3848(86)90171-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Moynier I, Bourret E, Fussellier M, Bardet L. [Determination of micro-quantities of serum lithium by atomic absorption spectrophotometry. Significance and applications]. Pathol Biol (Paris) 1986; 34:51-6. [PMID: 3517770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The dilution of serum and the ionic components having an usual effect upon the lithium assay is examined about their influences in the determination of lithium microquantities. These are discussed according to the technique selected as well as the normal ionic variations that may be come across in serums. The method was applied to determination of serum lithium rate in a group of old subjects. The got lithium distribution is unsymmetrical at lower rates and no influence of age or sex was obvious.
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Bourret E, Moynier I, Bardet L, Fussellier M. Determination de microquantites de lithium serique par spectrometrie d'absorption atomique sans flamme. Anal Chim Acta 1985. [DOI: 10.1016/s0003-2670(00)82603-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bourret E, Bardet L. Approche du mécanisme de gélification des sols d'agarose III. Comportement rhéologique de divers échantillons et étude énergétique de leur gélification. Int J Pharm 1982. [DOI: 10.1016/0378-5173(82)90130-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bourret E, Bardet L, Fortune R. [A simple hemolytic plate method for complement activity estimation (author's transl)]. Pathol Biol (Paris) 1981; 29:461-7. [PMID: 7029425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The previous single radial haemolysis method is simplified for complement activity assay in human serums. The proceeding a "one point" test is described. This new technique is remarkable by its simplicity and rapidity. A study of the precision shows tha possibility of to make use of this simple "one point" hemolytic plate method.
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Bourret E, Bardet L. [A study of the single radial haemolysis optimization for complement haemolytic activity assay (author's transl)]. Clin Chim Acta 1980; 102:1-9. [PMID: 6993047 DOI: 10.1016/0009-8981(80)90427-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The experimental conditions for single radial haemolysis are analysed in order to optimize the haemolytic plate method for the assay of human total complement. The amount of haemolytic antibody used for sensitization of red cells, the concentration of sensitized sheep erythrocytes, the thickness of agarose layer, and the diameters of wells all exercise an influence on the area of haemolysis. The effects of these parameters are investigated with a view to obtaining the clearest reading and greatest sensitivity of the haemolytic activity plate method, and at the same time verifying the validity of the assay and the precision of the human serum haemolytic titres. This work reports the optimal experimental requirements with regard to the factors studied for minimizing the sources of error in complement haemolytic plate assay.
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Bourret E, Bastide M, Bastide JM, Bardet L. [Titration of the hemolytic activity of human complement after radial diffusion]. C R Acad Hebd Seances Acad Sci D 1977; 284:1123-6. [PMID: 406065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The hemolytic activity of human complement is evaluated after diffusion in agarose containing sensitized erythrocytes. The results show a linear relation between hemolysis area and logarithm of concentration.
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Bardet L, Cassanas-Fabre G, Bourret E. Spectres de vibration des acides cyclopentaniques C4H8CHCOOH, C4H8CHCOOD, C4H8CDCOOH, C4H8CDCOOD et de leurs sels de so. J Mol Struct 1975. [DOI: 10.1016/0022-2860(75)80042-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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