1
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Dainone PA, Prestes NF, Renucci P, Bouché A, Morassi M, Devaux X, Lindemann M, George JM, Jaffrès H, Lemaitre A, Xu B, Stoffel M, Chen T, Lombez L, Lagarde D, Cong G, Ma T, Pigeat P, Vergnat M, Rinnert H, Marie X, Han X, Mangin S, Rojas-Sánchez JC, Wang JP, Beard MC, Gerhardt NC, Žutić I, Lu Y. Author Correction: Controlling the helicity of light by electrical magnetization switching. Nature 2024; 629:E8. [PMID: 38609503 DOI: 10.1038/s41586-024-07401-4] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2024]
Affiliation(s)
| | | | - Pierre Renucci
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | - Alexandre Bouché
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Martina Morassi
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, France
| | - Xavier Devaux
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Markus Lindemann
- Photonics and Terahertz Technology, Ruhr-Universität Bochum, Bochum, Germany
| | - Jean-Marie George
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Henri Jaffrès
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Aristide Lemaitre
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, France
| | - Bo Xu
- Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Mathieu Stoffel
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Tongxin Chen
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Laurent Lombez
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | | | - Guangwei Cong
- Platform Photonics Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Tianyi Ma
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
| | - Philippe Pigeat
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Michel Vergnat
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Hervé Rinnert
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Xavier Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
| | - Stephane Mangin
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | | | - Jian-Ping Wang
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Matthew C Beard
- Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Nils C Gerhardt
- Photonics and Terahertz Technology, Ruhr-Universität Bochum, Bochum, Germany
| | - Igor Žutić
- Department of Physics, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Yuan Lu
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France.
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2
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Abdukayumov K, Mičica M, Ibrahim F, Vojáček L, Vergnaud C, Marty A, Veuillen JY, Mallet P, de Moraes IG, Dosenovic D, Gambarelli S, Maurel V, Wright A, Tignon J, Mangeney J, Ouerghi A, Renard V, Mesple F, Li J, Bonell F, Okuno H, Chshiev M, George JM, Jaffrès H, Dhillon S, Jamet M. Atomic-Layer Controlled Transition from Inverse Rashba-Edelstein Effect to Inverse Spin Hall Effect in 2D PtSe 2 Probed by THz Spintronic Emission. Adv Mater 2024; 36:e2304243. [PMID: 38160244 DOI: 10.1002/adma.202304243] [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] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 11/09/2023] [Indexed: 01/03/2024]
Abstract
2D materials, such as transition metal dichalcogenides, are ideal platforms for spin-to-charge conversion (SCC) as they possess strong spin-orbit coupling (SOC), reduced dimensionality and crystal symmetries as well as tuneable band structure, compared to metallic structures. Moreover, SCC can be tuned with the number of layers, electric field, or strain. Here, SCC in epitaxially grown 2D PtSe2 by THz spintronic emission is studied since its 1T crystal symmetry and strong SOC favor SCC. High quality of as-grown PtSe2 layers is demonstrated, followed by in situ ferromagnet deposition by sputtering that leaves the PtSe2 unaffected, resulting in well-defined clean interfaces as evidenced with extensive characterization. Through this atomic growth control and using THz spintronic emission, the unique thickness-dependent electronic structure of PtSe2 allows the control of SCC. Indeed, the transition from the inverse Rashba-Edelstein effect (IREE) in 1-3 monolayers (ML) to the inverse spin Hall effect (ISHE) in multilayers (>3 ML) of PtSe2 enabling the extraction of the perpendicular spin diffusion length and relative strength of IREE and ISHE is demonstrated. This band structure flexibility makes PtSe2 an ideal candidate to explore the underlying mechanisms and engineering of the SCC as well as for the development of tuneable THz spintronic emitters.
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Affiliation(s)
- Khasan Abdukayumov
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Martin Mičica
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Fatima Ibrahim
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Libor Vojáček
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Céline Vergnaud
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Alain Marty
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Jean-Yves Veuillen
- CNRS, Université Grenoble Alpes, Grenoble INP-UGA, Institut NéeL, Grenoble, 38000, France
| | - Pierre Mallet
- CNRS, Université Grenoble Alpes, Grenoble INP-UGA, Institut NéeL, Grenoble, 38000, France
| | | | | | - Serge Gambarelli
- CEA, CNRS, IRIG-SYMMES, Université Grenoble Alpes, Grenoble, 38000, France
| | - Vincent Maurel
- CEA, CNRS, IRIG-SYMMES, Université Grenoble Alpes, Grenoble, 38000, France
| | - Adrien Wright
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Jérôme Tignon
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Juliette Mangeney
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Abdelkarim Ouerghi
- CNRS, Centre de Nanosciences et de Nanotechnologies, Université Paris-Saclay, Palaiseau, 91120, France
| | - Vincent Renard
- CEA, IRIG-Pheliqs, Université Grenoble Alpes, Grenoble, 38000, France
| | - Florie Mesple
- CEA, IRIG-Pheliqs, Université Grenoble Alpes, Grenoble, 38000, France
| | - Jing Li
- CEA, Leti, Université Grenoble Alpes, Grenoble, 38000, France
| | - Frédéric Bonell
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Hanako Okuno
- CEA, IRIG-MEM, Université Grenoble Alpes, Grenoble, 38000, France
| | - Mairbek Chshiev
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
- Institut Universitaire de France, Paris, 75231, France
| | - Jean-Marie George
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau, F-91767, France
| | - Henri Jaffrès
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau, F-91767, France
| | - Sukhdeep Dhillon
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Matthieu Jamet
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
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3
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Husain S, Prestes NF, Fayet O, Collin S, Godel F, Jacquet E, Denneulin T, Dunin-Borkowski RE, Thiaville A, Bibes M, Jaffrès H, Reyren N, Fert A, George JM. Field-Free Switching of Perpendicular Magnetization in an Ultrathin Epitaxial Magnetic Insulator. Nano Lett 2024; 24:2743-2750. [PMID: 38393986 DOI: 10.1021/acs.nanolett.3c04413] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
For energy-efficient magnetic memories, switching of perpendicular magnetization by spin-orbit torque (SOT) appears to be a promising solution. This SOT switching requires the assistance of an in-plane magnetic field to break the symmetry. Here, we demonstrate the field-free SOT switching of a perpendicularly magnetized thulium iron garnet (Tm3Fe5O12, TmIG). The polarity of the switching loops, clockwise or counterclockwise, is determined by the direction of the initial current pulses, in contrast with field-assisted switching where the polarity is controlled by the direction of the magnetic field. From Brillouin light scattering, we determined the Dzyaloshinskii-Moriya interaction (DMI) induced by the Pt-TmIG interface. We will discuss the possible origins of field-free switching and the roles of the interfacial DMI and cubic magnetic anisotropy of TmIG. This discussion is substantiated by magnetotransport, Kerr microscopy, and micromagnetic simulations. Our observation of field-free electrical switching of a magnetic insulator is an important milestone for low-power spintronic devices.
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Affiliation(s)
- Sajid Husain
- Laboratoire Albert Fert CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767 Palaiseau Cedex, France
| | - Nicholas F Prestes
- Laboratoire Albert Fert CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767 Palaiseau Cedex, France
| | - Olivier Fayet
- Laboratoire Albert Fert CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767 Palaiseau Cedex, France
| | - Sophie Collin
- Laboratoire Albert Fert CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767 Palaiseau Cedex, France
| | - Florian Godel
- Laboratoire Albert Fert CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767 Palaiseau Cedex, France
| | - Eric Jacquet
- Laboratoire Albert Fert CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767 Palaiseau Cedex, France
| | - Thibaud Denneulin
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - André Thiaville
- Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Manuel Bibes
- Laboratoire Albert Fert CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767 Palaiseau Cedex, France
| | - Henri Jaffrès
- Laboratoire Albert Fert CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767 Palaiseau Cedex, France
| | - Nicolas Reyren
- Laboratoire Albert Fert CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767 Palaiseau Cedex, France
| | - Albert Fert
- Laboratoire Albert Fert CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767 Palaiseau Cedex, France
| | - Jean-Marie George
- Laboratoire Albert Fert CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767 Palaiseau Cedex, France
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4
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Dainone PA, Prestes NF, Renucci P, Bouché A, Morassi M, Devaux X, Lindemann M, George JM, Jaffrès H, Lemaitre A, Xu B, Stoffel M, Chen T, Lombez L, Lagarde D, Cong G, Ma T, Pigeat P, Vergnat M, Rinnert H, Marie X, Han X, Mangin S, Rojas-Sánchez JC, Wang JP, Beard MC, Gerhardt NC, Žutić I, Lu Y. Controlling the helicity of light by electrical magnetization switching. Nature 2024; 627:783-788. [PMID: 38538937 DOI: 10.1038/s41586-024-07125-5] [Citation(s) in RCA: 1] [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] [Received: 09/15/2023] [Accepted: 01/26/2024] [Indexed: 04/01/2024]
Abstract
Controlling the intensity of emitted light and charge current is the basis of transferring and processing information1. By contrast, robust information storage and magnetic random-access memories are implemented using the spin of the carrier and the associated magnetization in ferromagnets2. The missing link between the respective disciplines of photonics, electronics and spintronics is to modulate the circular polarization of the emitted light, rather than its intensity, by electrically controlled magnetization. Here we demonstrate that this missing link is established at room temperature and zero applied magnetic field in light-emitting diodes2-7, through the transfer of angular momentum between photons, electrons and ferromagnets. With spin-orbit torque8-11, a charge current generates also a spin current to electrically switch the magnetization. This switching determines the spin orientation of injected carriers into semiconductors, in which the transfer of angular momentum from the electron spin to photon controls the circular polarization of the emitted light2. The spin-photon conversion with the nonvolatile control of magnetization opens paths to seamlessly integrate information transfer, processing and storage. Our results provide substantial advances towards electrically controlled ultrafast modulation of circular polarization and spin injection with magnetization dynamics for the next-generation information and communication technology12, including space-light data transfer. The same operating principle in scaled-down structures or using two-dimensional materials will enable transformative opportunities for quantum information processing with spin-controlled single-photon sources, as well as for implementing spin-dependent time-resolved spectroscopies.
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Affiliation(s)
| | | | - Pierre Renucci
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | - Alexandre Bouché
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Martina Morassi
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, France
| | - Xavier Devaux
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Markus Lindemann
- Photonics and Terahertz Technology, Ruhr-Universität Bochum, Bochum, Germany
| | - Jean-Marie George
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Henri Jaffrès
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Aristide Lemaitre
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, France
| | - Bo Xu
- Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Mathieu Stoffel
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Tongxin Chen
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Laurent Lombez
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | | | - Guangwei Cong
- Platform Photonics Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Tianyi Ma
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
| | - Philippe Pigeat
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Michel Vergnat
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Hervé Rinnert
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | - Xavier Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
| | - Stephane Mangin
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France
| | | | - Jian-Ping Wang
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Matthew C Beard
- Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Nils C Gerhardt
- Photonics and Terahertz Technology, Ruhr-Universität Bochum, Bochum, Germany
| | - Igor Žutić
- Department of Physics, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Yuan Lu
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France.
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5
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Sahu P, Yang Y, Fan Y, Jaffrès H, Chen JY, Devaux X, Fagot-Revurat Y, Migot S, Rongione E, Chen T, Abel Dainone P, George JM, Dhillon S, Micica M, Lu Y, Wang JP. Room Temperature Spin-to-Charge Conversion in Amorphous Topological Insulating Gd-Alloyed Bi xSe 1-x/CoFeB Bilayers. ACS Appl Mater Interfaces 2023; 15:38592-38602. [PMID: 37550946 DOI: 10.1021/acsami.3c07695] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
Disordered topological insulator (TI) films have gained intense interest by benefiting from both the TI's exotic transport properties and the advantage of mass production by sputtering. Here, we report on the clear evidence of spin-charge conversion (SCC) in amorphous Gd-alloyed BixSe1-x (BSG)/CoFeB bilayers fabricated by sputtering, which could be related to the amorphous TI surface states. Two methods have been employed to study SCC in BSG (tBSG = 6-16 nm)/CoFeB(5 nm) bilayers with different BSG thicknesses. First, spin pumping is used to generate a spin current in CoFeB and detect SCC by the inverse Edelstein effect (IEE). The maximum SCC efficiency (SCE) is measured to be as large as 0.035 nm (IEE length λIEE) in a 6 nm thick BSG sample, which shows a strong decay when tBSG increases due to the increase of BSG surface roughness. The second method is THz time-domain spectroscopy, which reveals a small tBSG dependence of SCE, validating the occurrence of a pure interface state-related SCC. Furthermore, our angle-resolved photoemission spectroscopy data show dispersive two-dimensional surface states that cross the bulk gap until the Fermi level, strengthening the possibility of SCC due to the amorphous TI states. Our studies provide a new experimental direction toward the search for topological systems in amorphous solids.
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Affiliation(s)
- Protyush Sahu
- School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, Minnesota 55455, United States
| | - Yifei Yang
- Department of Electrical and Computer Engineering, University of Minnesota, 200 Union Street SE, Minneapolis, Minnesota 55455, United States
| | - Yihong Fan
- Department of Electrical and Computer Engineering, University of Minnesota, 200 Union Street SE, Minneapolis, Minnesota 55455, United States
| | - Henri Jaffrès
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Jun-Yang Chen
- Department of Electrical and Computer Engineering, University of Minnesota, 200 Union Street SE, Minneapolis, Minnesota 55455, United States
| | - Xavier Devaux
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Yannick Fagot-Revurat
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Sylvie Migot
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Enzo Rongione
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005 Paris, France
| | - Tongxin Chen
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Pambiang Abel Dainone
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Jean-Marie George
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Sukhdeep Dhillon
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005 Paris, France
| | - Martin Micica
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005 Paris, France
| | - Yuan Lu
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Jian-Ping Wang
- School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, Minnesota 55455, United States
- Department of Electrical and Computer Engineering, University of Minnesota, 200 Union Street SE, Minneapolis, Minnesota 55455, United States
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6
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Krishnia S, Sassi Y, Ajejas F, Sebe N, Reyren N, Collin S, Denneulin T, Kovács A, Dunin-Borkowski RE, Fert A, George JM, Cros V, Jaffrès H. Large Interfacial Rashba Interaction Generating Strong Spin-Orbit Torques in Atomically Thin Metallic Heterostructures. Nano Lett 2023; 23:6785-6791. [PMID: 37524333 PMCID: PMC10416352 DOI: 10.1021/acs.nanolett.2c05091] [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] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 06/22/2023] [Indexed: 08/02/2023]
Abstract
The hallmark of spintronics has been the ability of spin-orbit interactions to convert a charge current into a spin current and vice versa, mainly in the bulk of heavy metal thin films. Here, we demonstrate how a light metal interface profoundly affects both the nature of spin-orbit torques and its efficiency in terms of damping-like (HDL) and field-like (HFL) effective fields in ultrathin Co films. We measure unexpectedly HFL/HDL ratios much larger than 1 by inserting a nanometer-thin Al metallic layer in Pt|Co|Al|Pt as compared to a similar stacking, including Cu as a reference. From our modeling, these results evidence the existence of large Rashba interaction at the Co|Al interface generating a giant HFL, which is not expected from a metallic interface. The occurrence of such enhanced torques from an interfacial origin is further validated by demonstrating current-induced magnetization reversal showing a significant decrease of the critical current for switching.
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Affiliation(s)
- Sachin Krishnia
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Yanis Sassi
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Fernando Ajejas
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Nicolas Sebe
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Nicolas Reyren
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Sophie Collin
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Thibaud Denneulin
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C
1) and Peter Grünberg Institut (PGI-5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - András Kovács
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C
1) and Peter Grünberg Institut (PGI-5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Rafal E. Dunin-Borkowski
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C
1) and Peter Grünberg Institut (PGI-5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Albert Fert
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Jean-Marie George
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Vincent Cros
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Henri Jaffrès
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
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7
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van Eijk L, Seidel M, Pannek K, George JM, Fiori S, Guzzetta A, Coulthard A, Bursle J, Ware RS, Bradford D, Rose S, Colditz PB, Boyd RN, Fripp J. Automating Quantitative Measures of an Established Conventional MRI Scoring System for Preterm-Born Infants Scanned between 29 and 47 Weeks' Postmenstrual Age. AJNR Am J Neuroradiol 2021; 42:1870-1877. [PMID: 34413061 DOI: 10.3174/ajnr.a7230] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 05/03/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Conventional MR imaging scoring is a valuable tool for risk stratification and prognostication of outcomes, but manual scoring is time-consuming, operator-dependent, and requires high-level expertise. This study aimed to automate the regional measurements of an established brain MR imaging scoring system for preterm neonates scanned between 29 and 47 weeks' postmenstrual age. MATERIALS AND METHODS This study used T2WI from the longitudinal Prediction of PREterm Motor Outcomes cohort study and the developing Human Connectome Project. Measures of biparietal width, interhemispheric distance, callosal thickness, transcerebellar diameter, lateral ventricular diameter, and deep gray matter area were extracted manually (Prediction of PREterm Motor Outcomes study only) and automatically. Scans with poor quality, failure of automated analysis, or severe pathology were excluded. Agreement, reliability, and associations between manual and automated measures were assessed and compared against statistics for manual measures. Associations between measures with postmenstrual age, gestational age at birth, and birth weight were examined (Pearson correlation) in both cohorts. RESULTS A total of 652 MRIs (86%) were suitable for analysis. Automated measures showed good-to-excellent agreement and good reliability with manual measures, except for interhemispheric distance at early MR imaging (scanned between 29 and 35 weeks, postmenstrual age; in line with poor manual reliability) and callosal thickness measures. All measures were positively associated with postmenstrual age (r = 0.11-0.94; R2 = 0.01-0.89). Negative and positive associations were found with gestational age at birth (r = -0.26-0.71; R2 = 0.05-0.52) and birth weight (r = -0.25-0.75; R2 = 0.06-0.56). Automated measures were successfully extracted for 80%-99% of suitable scans. CONCLUSIONS Measures of brain injury and impaired brain growth can be automatically extracted from neonatal MR imaging, which could assist with clinical reporting.
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Affiliation(s)
- L van Eijk
- From The Australian e-Health Research Centre (L.v.E., M.S., K.P., D.B., S.R., J.F.), Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Brisbane, Australia.,Faculty of Medicine (L.V.E., M.S.), The University of Queensland, Brisbane, Australia
| | - M Seidel
- From The Australian e-Health Research Centre (L.v.E., M.S., K.P., D.B., S.R., J.F.), Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Brisbane, Australia.,Faculty of Medicine (L.V.E., M.S.), The University of Queensland, Brisbane, Australia
| | - K Pannek
- From The Australian e-Health Research Centre (L.v.E., M.S., K.P., D.B., S.R., J.F.), Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Brisbane, Australia
| | - J M George
- Queensland Cerebral Palsy and Rehabilitation Research Centre (J.M.G., R.N.B.), Centre for Children's Health Research, The University of Queensland, Brisbane, Australia
| | - S Fiori
- Department of Developmental Neuroscience (S.F., A.G.), Istituto di Ricovero e Cura a Carattere Scientifico Stella Maris, Pisa, Italy
| | - A Guzzetta
- Department of Developmental Neuroscience (S.F., A.G.), Istituto di Ricovero e Cura a Carattere Scientifico Stella Maris, Pisa, Italy.,Department of Clinical and Experimental Medicine (A.G.), University of Pisa, Pisa, Italy
| | - A Coulthard
- Department of Medical Imaging (A.C., J.B.), Royal Brisbane and Women's Hospital, Brisbane, Australia.,Discipline of Medical Imaging (A.C.), The University of Queensland, Brisbane, Australia
| | - J Bursle
- Department of Medical Imaging (A.C., J.B.), Royal Brisbane and Women's Hospital, Brisbane, Australia
| | - R S Ware
- Menzies Health Institute Queensland (R.S.W.), Griffith University, Brisbane, Australia
| | - D Bradford
- From The Australian e-Health Research Centre (L.v.E., M.S., K.P., D.B., S.R., J.F.), Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Brisbane, Australia
| | - S Rose
- From The Australian e-Health Research Centre (L.v.E., M.S., K.P., D.B., S.R., J.F.), Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Brisbane, Australia
| | - P B Colditz
- Perinatal Research Centre (P.B.C.), University of Queenland Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia.,Perinatal Research Centre, Brisbane and Women's Hospital (P.B.C.), Brisbane, Australia
| | - R N Boyd
- Queensland Cerebral Palsy and Rehabilitation Research Centre (J.M.G., R.N.B.), Centre for Children's Health Research, The University of Queensland, Brisbane, Australia
| | - J Fripp
- From The Australian e-Health Research Centre (L.v.E., M.S., K.P., D.B., S.R., J.F.), Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Brisbane, Australia
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8
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Zhou Z, Marcon P, Devaux X, Pigeat P, Bouché A, Migot S, Jaafar A, Arras R, Vergnat M, Ren L, Tornatzky H, Robert C, Marie X, George JM, Jaffrès HY, Stoffel M, Rinnert H, Wei Z, Renucci P, Calmels L, Lu Y. Large Perpendicular Magnetic Anisotropy in Ta/CoFeB/MgO on Full-Coverage Monolayer MoS 2 and First-Principles Study of Its Electronic Structure. ACS Appl Mater Interfaces 2021; 13:32579-32589. [PMID: 34196522 DOI: 10.1021/acsami.1c08805] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A perpendicularly magnetized spin injector with a high Curie temperature is a prerequisite for developing spin optoelectronic devices on two-dimensional (2D) materials working at room temperature (RT) with zero applied magnetic field. Here, we report the growth of Ta/CoFeB/MgO structures with large perpendicular magnetic anisotropy (PMA) on full-coverage monolayer (ML) molybdenum disulfide (MoS2). A large perpendicular interface anisotropy energy of 0.975 mJ/m2 has been obtained at the CoFeB/MgO interface, comparable to that observed in magnetic tunnel junction systems. It is found that the insertion of MgO between the ferromagnetic (FM) metal and the 2D material can effectively prevent the diffusion of the FM atoms into the 2D material. Moreover, the MoS2 ML favors a MgO(001) texture and plays a critical role in establishing the large PMA. First-principles calculations on a similar Fe/MgO/MoS2 structure reveal that the MgO thickness can modify the MoS2 band structure, from a direct band gap with 3ML-MgO to an indirect band gap with 7 ML-MgO. The proximity effect induced by Fe results in splitting of 10 meV in the valence band at the Γ point for the 3ML-MgO structure, while it is negligible for the 7 ML-MgO structure. These results pave the way to develop RT spin optoelectronic devices based on 2D transition-metal dichalcogenide materials.
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Affiliation(s)
- Ziqi Zhou
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences & Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100083, China
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Paul Marcon
- CEMES, CNRS, Université de Toulouse, 29 rue Jeanne Marvig, BP 94347, F-31055 Toulouse, France
| | - Xavier Devaux
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Philippe Pigeat
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Alexandre Bouché
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Sylvie Migot
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Abdallah Jaafar
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Rémi Arras
- CEMES, CNRS, Université de Toulouse, 29 rue Jeanne Marvig, BP 94347, F-31055 Toulouse, France
| | - Michel Vergnat
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Lei Ren
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - Hans Tornatzky
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - Cedric Robert
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - Xavier Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - Jean-Marie George
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Henri-Yves Jaffrès
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Mathieu Stoffel
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Hervé Rinnert
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Zhongming Wei
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences & Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100083, China
| | - Pierre Renucci
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - Lionel Calmels
- CEMES, CNRS, Université de Toulouse, 29 rue Jeanne Marvig, BP 94347, F-31055 Toulouse, France
| | - Yuan Lu
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
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9
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George JM, Xu Y, Nursa'adah BJ, Lim SF, Low LL, Chan DX. Collaboration between a tertiary pain centre and community teams during the pandemic. Br J Community Nurs 2020; 25:480-488. [PMID: 33030369 DOI: 10.12968/bjcn.2020.25.10.480] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
People with chronic pain faced potential treatment disruption during the COVID-19 pandemic in Singapore, as the focus of healthcare shifted. A model of rapid integration of a pain centre with community healthcare teams was implemented to care for vulnerable older patients with chronic pain and multiple comorbidities. Telemedicine and home visits by community nurses were used, with risk-mitigation measures, ensuring comprehensive assessment and treatment compliance. Medications from pain physicians were delivered at home through a hospital pharmacy. A secure national electronic health records system used by all teams ensured seamless access and documentation. Potential emergency department visits, admissions and delayed discharges were thus avoided. Integration of community teams with chronic pain management services can be recommended to ensure pandemic preparedness.
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Affiliation(s)
- J M George
- Senior Consultant, Department of Pain Medicine and Division of Anaesthesiology, Singapore General Hospital and Sengkang General Hospital, Singhealth
| | - Y Xu
- Senior Nurse Clinician (Community Nurse), RHS-Community Nursing, Population Health and Integrated Care Office, Singapore General Hospital
| | - B J Nursa'adah
- Senior Staff Nurse (Community Nurse), RHS-Community Nursing, Population Health and Integrated Care Office, Singapore General Hospital
| | - S F Lim
- Deputy Director of Nursing, RHS-Community Nursing, Population Health and Integrated Care Office, Singapore General Hospital
| | - L L Low
- Director, Population Health and Integrated Care Office, Singapore General Hospital; Head, Post-acute and continuing care, Outram Community Hospital
| | - Diana Xh Chan
- Head and Consultant, Department of Pain Medicine and Division of Anaesthesiology and Perioperative Medicine, Singapore General Hospital; Director, Pain Management Services, Sengkang General Hospital
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10
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Cerqueira C, Qin JY, Dang H, Djeffal A, Le Breton JC, Hehn M, Rojas-Sanchez JC, Devaux X, Suire S, Migot S, Schieffer P, Mussot JG, Łaczkowski P, Anane A, Petit-Watelot S, Stoffel M, Mangin S, Liu Z, Cheng BW, Han XF, Jaffrès H, George JM, Lu Y. Evidence of Pure Spin-Current Generated by Spin Pumping in Interface-Localized States in Hybrid Metal-Silicon-Metal Vertical Structures. Nano Lett 2019; 19:90-99. [PMID: 30472859 DOI: 10.1021/acs.nanolett.8b03386] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Due to the difficulty of growing high-quality semiconductors on ferromagnetic metals, the study of spin diffusion transport in Si was limited to lateral geometry devices. In this work, by using an ultrahigh-vacuum wafer-bonding technique, we have successfully fabricated metal-semiconductor-metal CoFeB/MgO/Si/Pt vertical structures. We hereby demonstrate pure spin-current injection and transport in the perpendicular current flow geometry over a distance larger than 2 μm in n-type Si at room temperature. In those experiments, a pure propagating spin current is generated via ferromagnetic resonance spin pumping and converted into a measurable voltage by using the inverse spin Hall effect occurring in the top Pt layer. A systematic study varying both Si and MgO thicknesses reveals the important role played by the localized states at the MgO-Si interface for the spin-current generation. Proximity effects involving indirect exchange interactions between the ferromagnet and the MgO-Si interface states appears to be a prerequisite to establishing the necessary out-of-equilibrium spin population in Si under the spin-pumping action.
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Affiliation(s)
- Carolina Cerqueira
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay , 91767 , Palaiseau , France
- Laboratoire des Solides Irradiés, École Polytechnique, CNRS, CEA , Université Paris-Saclay , 91128 Palaiseau , France
| | - Jian Yin Qin
- Université de Lorraine , CNRS, Institut Jean Lamour, UMR 7198, campus ARTEM , 2 Allée André Guinier , 54011 Nancy , France
- Beijing National Laboratory of Condensed Matter Physics , Institute of Physics, University of Chinese Academy of Sciences , Beijing 100190 , PR China
| | - Huong Dang
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay , 91767 , Palaiseau , France
| | - Abdelhak Djeffal
- Université de Lorraine , CNRS, Institut Jean Lamour, UMR 7198, campus ARTEM , 2 Allée André Guinier , 54011 Nancy , France
| | | | - Michel Hehn
- Université de Lorraine , CNRS, Institut Jean Lamour, UMR 7198, campus ARTEM , 2 Allée André Guinier , 54011 Nancy , France
| | - Juan-Carlos Rojas-Sanchez
- Université de Lorraine , CNRS, Institut Jean Lamour, UMR 7198, campus ARTEM , 2 Allée André Guinier , 54011 Nancy , France
| | - Xavier Devaux
- Université de Lorraine , CNRS, Institut Jean Lamour, UMR 7198, campus ARTEM , 2 Allée André Guinier , 54011 Nancy , France
| | - Stéphane Suire
- Université de Lorraine , CNRS, Institut Jean Lamour, UMR 7198, campus ARTEM , 2 Allée André Guinier , 54011 Nancy , France
| | - Sylvie Migot
- Université de Lorraine , CNRS, Institut Jean Lamour, UMR 7198, campus ARTEM , 2 Allée André Guinier , 54011 Nancy , France
| | - Philippe Schieffer
- Univ RennesCNRS, IPR (Institut de Physique de Rennes) - UMR 6251 , F-35000 Rennes , France
| | - Jean-Georges Mussot
- Université de Lorraine , CNRS, Institut Jean Lamour, UMR 7198, campus ARTEM , 2 Allée André Guinier , 54011 Nancy , France
| | - Piotr Łaczkowski
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay , 91767 , Palaiseau , France
| | - Abdelmadjid Anane
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay , 91767 , Palaiseau , France
| | - Sebastien Petit-Watelot
- Université de Lorraine , CNRS, Institut Jean Lamour, UMR 7198, campus ARTEM , 2 Allée André Guinier , 54011 Nancy , France
| | - Mathieu Stoffel
- Université de Lorraine , CNRS, Institut Jean Lamour, UMR 7198, campus ARTEM , 2 Allée André Guinier , 54011 Nancy , France
| | - Stéphane Mangin
- Université de Lorraine , CNRS, Institut Jean Lamour, UMR 7198, campus ARTEM , 2 Allée André Guinier , 54011 Nancy , France
| | - Zhi Liu
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Center of Materials Science and Optoelectronics Engineering , University of Chinese Academy of Sciences Chinese Academy of Sciences , Beijing 100083 , PR China
| | - Bu Wen Cheng
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Center of Materials Science and Optoelectronics Engineering , University of Chinese Academy of Sciences Chinese Academy of Sciences , Beijing 100083 , PR China
| | - Xiu Feng Han
- Beijing National Laboratory of Condensed Matter Physics , Institute of Physics, University of Chinese Academy of Sciences , Beijing 100190 , PR China
| | - Henri Jaffrès
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay , 91767 , Palaiseau , France
| | - Jean-Marie George
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Sud, Université Paris-Saclay , 91767 , Palaiseau , France
| | - Yuan Lu
- Université de Lorraine , CNRS, Institut Jean Lamour, UMR 7198, campus ARTEM , 2 Allée André Guinier , 54011 Nancy , France
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11
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Tao B, Barate P, Devaux X, Renucci P, Frougier J, Djeffal A, Liang S, Xu B, Hehn M, Jaffrès H, George JM, Marie X, Mangin S, Han X, Wang Z, Lu Y. Atomic-scale understanding of high thermal stability of the Mo/CoFeB/MgO spin injector for spin-injection in remanence. Nanoscale 2018; 10:10213-10220. [PMID: 29789851 DOI: 10.1039/c8nr02250j] [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: 06/08/2023]
Abstract
Remanent spin injection into a spin light emitting diode (spin-LED) at zero magnetic field is a prerequisite for future application of spin optoelectronics. Here, we demonstrate the remanent spin injection into GaAs based LEDs with a thermally stable Mo/CoFeB/MgO spin injector. A systematic study of magnetic properties, polarization-resolved electroluminescence (EL) and atomic-scale interfacial structures has been performed in comparison with the Ta/CoFeB/MgO spin injector. The perpendicular magnetic anisotropy (PMA) of the Mo/CoFeB/MgO injector shows more advanced thermal stability than that of the Ta/CoFeB/MgO injector and robust PMA can be maintained up to 400 °C annealing. The remanent circular polarization (PC) of EL from the Mo capped spin-LED reaches a maximum value of 10% after 300 °C annealing, and even remains at 4% after 400 °C annealing. In contrast, the Ta capped spin-LED almost completely loses the remanent PC under 400 °C annealing. Combined advanced electron microscopy and spectroscopy studies reveal that a large amount of Ta diffuses into the MgO tunneling barrier through the CoFeB layer after 400 °C annealing. However, the diffusion of Mo into CoFeB is limited and never reaches the MgO barrier. These findings afford a comprehensive perspective to use the highly thermally stable Mo/CoFeB/MgO spin injector for efficient electrical spin injection in remanence.
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Affiliation(s)
- Bingshan Tao
- Institut Jean Lamour, UMR 7198, CNRS-Université de Lorraine, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France.
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12
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Alouini M, Frougier J, Joly A, Baili G, Dolfi D, George JM. VSPIN: a new model relying on the vectorial description of the laser field for predicting the polarization dynamics of spin-injected V(e)CSELs. Opt Express 2018; 26:6739-6757. [PMID: 29609363 DOI: 10.1364/oe.26.006739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/15/2018] [Indexed: 06/08/2023]
Abstract
A new vectorial model (VSPIN) based on the Jones formalism is proposed to describe the polarization dynamics of spin injected V(e)CSELs. This general modelling framework accounts for spin injection effects as a gain circular dichroism in the active medium and provides guidelines for developing functional spin-controlled lasers. We investigate the detrimental role of phase anisotropy on polarization switching and show that it can be overcome by preparing the laser cavity to achieve efficient polarization switching under low effective spin injection. The VSPIN model predictions have been confirmed experimentally and explain the polarization behavior of spin-VCSELs reported in the literature.
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13
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George JM, Fiori S, Fripp J, Pannek K, Bursle J, Moldrich RX, Guzzetta A, Coulthard A, Ware RS, Rose SE, Colditz PB, Boyd RN. Reply. AJNR Am J Neuroradiol 2017; 39:E40-E41. [PMID: 29170274 DOI: 10.3174/ajnr.a5478] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- J M George
- Queensland Cerebral Palsy and Rehabilitation Research Centre Centre for Children's Health Research Faculty of Medicine, University of Queensland Brisbane, Australia
| | - S Fiori
- Department of Developmental Neuroscience Stella Maris Scientific Institute Pisa, Italy
| | - J Fripp
- Health and Biosecurity The Australian e-Health Research Centre Commonwealth Scientific and Industrial Research Organisation Brisbane, Australia
| | - K Pannek
- Health and Biosecurity The Australian e-Health Research Centre Commonwealth Scientific and Industrial Research Organisation Brisbane, Australia
| | - J Bursle
- Department of Medical Imaging Royal Brisbane and Women's Hospital Brisbane, Australia
| | - R X Moldrich
- Centre for Clinical Research Faculty of Medicine, University of Queensland Brisbane, Australia
| | - A Guzzetta
- Department of Developmental Neuroscience Stella Maris Scientific Institute Pisa, Italy
| | - A Coulthard
- Department of Medical Imaging Royal Brisbane and Women's Hospital Brisbane, Australia.,Discipline of Medical Imaging University of Queensland Brisbane, Australia
| | - R S Ware
- Menzies Health Institute Queensland Griffith University Brisbane, Australia.,Queensland Centre for Intellectual and Developmental Disability University of Queensland Brisbane, Australia
| | - S E Rose
- Health and Biosecurity The Australian e-Health Research Centre Commonwealth Scientific and Industrial Research Organisation Brisbane, Australia
| | - P B Colditz
- Centre for Clinical Research Faculty of Medicine, University of Queensland Brisbane, Australia.,Perinatal Research Centre Royal Brisbane and Women's Hospital Brisbane, Australia
| | - R N Boyd
- Queensland Cerebral Palsy and Rehabilitation Research Centre Centre for Children's Health Research Faculty of Medicine, University of Queensland Brisbane, Australia
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14
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George JM, Fiori S, Fripp J, Pannek K, Bursle J, Moldrich RX, Guzzetta A, Coulthard A, Ware RS, Rose SE, Colditz PB, Boyd RN. Validation of an MRI Brain Injury and Growth Scoring System in Very Preterm Infants Scanned at 29- to 35-Week Postmenstrual Age. AJNR Am J Neuroradiol 2017; 38:1435-1442. [PMID: 28522659 DOI: 10.3174/ajnr.a5191] [Citation(s) in RCA: 31] [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] [Received: 10/19/2016] [Accepted: 02/21/2017] [Indexed: 01/15/2023]
Abstract
BACKGROUND AND PURPOSE The diagnostic and prognostic potential of brain MR imaging before term-equivalent age is limited until valid MR imaging scoring systems are available. This study aimed to validate an MR imaging scoring system of brain injury and impaired growth for use at 29 to 35 weeks postmenstrual age in infants born at <31 weeks gestational age. MATERIALS AND METHODS Eighty-three infants in a prospective cohort study underwent early 3T MR imaging between 29 and 35 weeks' postmenstrual age (mean, 32+2 ± 1+3 weeks; 49 males, born at median gestation of 28+4 weeks; range, 23+6-30+6 weeks; mean birthweight, 1068 ± 312 g). Seventy-seven infants had a second MR scan at term-equivalent age (mean, 40+6 ± 1+3 weeks). Structural images were scored using a modified scoring system which generated WM, cortical gray matter, deep gray matter, cerebellar, and global scores. Outcome at 12-months corrected age (mean, 12 months 4 days ± 1+2 weeks) consisted of the Bayley Scales of Infant and Toddler Development, 3rd ed. (Bayley III), and the Neuro-Sensory Motor Developmental Assessment. RESULTS Early MR imaging global, WM, and deep gray matter scores were negatively associated with Bayley III motor (regression coefficient for global score β = -1.31; 95% CI, -2.39 to -0.23; P = .02), cognitive (β = -1.52; 95% CI, -2.39 to -0.65; P < .01) and the Neuro-Sensory Motor Developmental Assessment outcomes (β = -1.73; 95% CI, -3.19 to -0.28; P = .02). Early MR imaging cerebellar scores were negatively associated with the Neuro-Sensory Motor Developmental Assessment (β = -5.99; 95% CI, -11.82 to -0.16; P = .04). Results were reconfirmed at term-equivalent-age MR imaging. CONCLUSIONS This clinically accessible MR imaging scoring system is valid for use at 29 to 35 weeks postmenstrual age in infants born very preterm. It enables identification of infants at risk of adverse outcomes before the current standard of term-equivalent age.
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Affiliation(s)
- J M George
- From the Queensland Cerebral Palsy and Rehabilitation Research Centre (J.M.G., R.N.B.), Centre for Children's Health Research, Faculty of Medicine
| | - S Fiori
- Stella Maris Scientific Institute (S.F., A.G.), Department of Developmental Neuroscience, Pisa, Italy
| | - J Fripp
- Health and Biosecurity (J.F., K.P., S.E.R.), The Australian e-Health Research Centre, Commonwealth Scientific and Industrial Research Organisation, Brisbane, Australia
| | - K Pannek
- Health and Biosecurity (J.F., K.P., S.E.R.), The Australian e-Health Research Centre, Commonwealth Scientific and Industrial Research Organisation, Brisbane, Australia
| | - J Bursle
- Department of Medical Imaging (J.B., A.C.)
| | - R X Moldrich
- University of Queensland Centre for Clinical Research (R.X.M., P.B.C.)
| | - A Guzzetta
- Stella Maris Scientific Institute (S.F., A.G.), Department of Developmental Neuroscience, Pisa, Italy
| | - A Coulthard
- Discipline of Medical Imaging (A.C.)
- Department of Medical Imaging (J.B., A.C.)
| | - R S Ware
- Queensland Centre for Intellectual and Developmental Disability (R.S.W.), The University of Queensland, Brisbane, Australia
- Menzies Health Institute Queensland (R.S.W.), Griffith University, Brisbane, Australia
| | - S E Rose
- Health and Biosecurity (J.F., K.P., S.E.R.), The Australian e-Health Research Centre, Commonwealth Scientific and Industrial Research Organisation, Brisbane, Australia
| | - P B Colditz
- University of Queensland Centre for Clinical Research (R.X.M., P.B.C.)
- Perinatal Research Centre (P.B.C.), Royal Brisbane and Women's Hospital, Brisbane, Australia
| | - R N Boyd
- From the Queensland Cerebral Palsy and Rehabilitation Research Centre (J.M.G., R.N.B.), Centre for Children's Health Research, Faculty of Medicine
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15
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Joly A, Baili G, Alouini M, George JM, Sagnes I, Pillet G, Dolfi D. Compensation of the residual linear anisotropy of phase in a vertical-external-cavity-surface-emitting laser for spin injection. Opt Lett 2017; 42:651-654. [PMID: 28146550 DOI: 10.1364/ol.42.000651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report on the compensation of the linear anisotropy of phase in a vertical-external-cavity surface-emitting laser from 21 to 0.5 mrad with an intracavity PLZT electro-optical ceramic. It allows dynamic and accurate control of the laser linear anisotropy, as well as dynamic control of the laser polarization eigenstates. At the birefringence compensation point, we observe an elliptical polarization state with 41° of ellipticity, rotated from its initial position of 32°. The experimental observations are in close agreement with the theoretical predictions. Finally, we are able to demonstrate control of the polarization state with spin injection.
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16
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Figueiredo-Prestes N, Zarpellon J, Jurca HF, Fernandes V, Varalda J, Schreiner WH, Mosca DH, Fichtner PFP, Fabrim ZE, Bouzehouane K, Deranlot C, George JM. Stabilization of perpendicular magnetic anisotropy in CeO2 films deposited on Co/Pt multilayers. RSC Adv 2016. [DOI: 10.1039/c6ra10392h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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] Open
Abstract
We report the stabilization of perpendicular magnetization, and anisotropy, in transparent CeO2 thin films integrated onto Co/Pt multilayered films.
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17
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Frougier J, Baili G, Sagnes I, Dolfi D, George JM, Alouini M. Accurate measurement of the residual birefringence in VECSEL: Towards understanding of the polarization behavior under spin-polarized pumping. Opt Express 2015; 23:9573-9588. [PMID: 25968994 DOI: 10.1364/oe.23.009573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this paper we report birefringence measurements of an optically pumped (100)-oriented InGaAs/GaAsP multiple quantum well (MQWs) Vertical External Cavity Surface Emitting Laser (VECSEL) in oscillating conditions. The proposed technique relies on the measurement in the microwave domain of the beatnote between the oscillating mode and the amplified spontaneous emission of the cross-polarized non-lasing field lying in the following longitudinal mode. This technique is shown to offer extremely high sensitivity and accuracy enabling to track the amount of residual birefringence according to the laser operation conditions. The experience fits within the broader framework of polarization selection in spin-injected lasers.
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18
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George JM, Menon M, Gupta P, Tan M. Use of strong opioids for chronic non-cancer pain: a retrospective analysis at a pain centre in Singapore. Singapore Med J 2013; 54:506-10. [DOI: 10.11622/smedj.2013173] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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19
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Birbeck GL, French JA, Perucca E, Simpson DM, Fraimow H, George JM, Okulicz JF, Clifford DB, Hachad H, Levy RH. Evidence-based guideline: Antiepileptic drug selection for people with HIV/AIDS: report of the Quality Standards Subcommittee of the American Academy of Neurology and the Ad Hoc Task Force of the Commission on Therapeutic Strategies of the International League Against Epilepsy. Neurology 2012; 78:139-45. [PMID: 22218281 DOI: 10.1212/wnl.0b013e31823efcf8] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To develop guidelines for selection of antiepileptic drugs (AEDs) among people with HIV/AIDS. METHODS The literature was systematically reviewed to assess the global burden of relevant comorbid entities, to determine the number of patients who potentially utilize AEDs and antiretroviral agents (ARVs), and to address AED-ARV interactions. RESULTS AND RECOMMENDATIONS AED-ARV administration may be indicated in up to 55% of people taking ARVs. Patients receiving phenytoin may require a lopinavir/ritonavir dosage increase of ~50% to maintain unchanged serum concentrations (Level C). Patients receiving valproic acid may require a zidovudine dosage reduction to maintain unchanged serum zidovudine concentrations (Level C). Coadministration of valproic acid and efavirenz may not require efavirenz dosage adjustment (Level C). Patients receiving ritonavir/atazanavir may require a lamotrigine dosage increase of ∼50% to maintain unchanged lamotrigine serum concentrations (Level C). Coadministration of raltegravir/atazanavir and lamotrigine may not require lamotrigine dosage adjustment (Level C). Coadministration of raltegravir and midazolam may not require midazolam dosage adjustment (Level C). Patients may be counseled that it is unclear whether dosage adjustment is necessary when other AEDs and ARVs are combined (Level U). It may be important to avoid enzyme-inducing AEDs in people on ARV regimens that include protease inhibitors or nonnucleoside reverse transcriptase inhibitors, as pharmacokinetic interactions may result in virologic failure, which has clinical implications for disease progression and development of ARV resistance. If such regimens are required for seizure control, patients may be monitored through pharmacokinetic assessments to ensure efficacy of the ARV regimen (Level C).
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Affiliation(s)
- G L Birbeck
- International Neurologic & Psychiatric Epidemiology Program, Michigan State University, East Lansing, USA.
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20
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Hassan H, Regnier N, George JM, Defaye G, Arquis E. A proposed technique to improve the filling of the mold cavity by polymer during injection molding. POLYM ENG SCI 2011. [DOI: 10.1002/pen.21895] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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21
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Etgens VH, de Camargo PC, Eddrief M, Mattana R, George JM, Garreau Y. Structure of ferromagnetic CrAs epilayers grown on GaAs(001). Phys Rev Lett 2004; 92:167205. [PMID: 15169258 DOI: 10.1103/physrevlett.92.167205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2003] [Indexed: 05/24/2023]
Abstract
Magnetic and structural properties of CrAs epilayers grown on GaAs(001) by molecular beam epitaxy have been studied. CrAs epilayers are orthorhombic for all thicknesses investigated but show a structural transition from a metastable phase for very thin films, to the usual bulk MnP-type orthorhombic phase at higher thicknesses. At intermediate thicknesses, there is a predominance of the new phase, although a contribution from the usual CrAs bulk phase remains clearly present. These results strongly suggest that the ferromagnetic signal measured at room temperature comes from the new metastable orthorhombic structure with an expanded b-axis induced by the substrate strain.
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Affiliation(s)
- V H Etgens
- Laboratoire de Minéralogie et de Cristallographie de Paris, CNRS-Universités Paris VI et VII, IPG-P, 4 Place Jussieu, 75252 Paris CEDEX, France.
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22
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Perrin RJ, Payton JE, Barnett DH, Wraight CL, Woods WS, Ye L, George JM. Epitope mapping and specificity of the anti-alpha-synuclein monoclonal antibody Syn-1 in mouse brain and cultured cell lines. Neurosci Lett 2003; 349:133-5. [PMID: 12946570 DOI: 10.1016/s0304-3940(03)00781-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
While alpha- and beta-synuclein largely overlap in their expression in the vertebrate brain, only alpha-synuclein accumulates in the fibrillar aggregates typical of Parkinson's disease. It is thus critical to have immunological reagents that distinguish between these two protein isoforms. The monoclonal antibody Syn-1 (Transduction Labs) has been frequently used for the specific detection of alpha-synuclein. In this report, the epitope for Syn-1 is localized within residues 91-99 of human alpha-synuclein. Sequence differences exist in this domain that account for the specificity of Syn-1 for alpha- versus beta-synuclein. However, Syn-1 also displays reactivity with additional species (approximately 45 kDa) in brain homogenates from both wild-type and alpha-synuclein null mice, indicating a potential for cross-reactivity with a protein species that is unrelated to alpha-synuclein in brain tissue or extracts.
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Affiliation(s)
- R J Perrin
- Medical Scholars Program, University of Illinois, Urbana, IL 61801, USA
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23
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Marangolo M, Gustavsson F, Eddrief M, Sainctavit P, Etgens VH, Cros V, Petroff F, George JM, Bencok P, Brookes NB. Magnetism of the Fe/ZnSe(001) interface. Phys Rev Lett 2002; 88:217202. [PMID: 12059497 DOI: 10.1103/physrevlett.88.217202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2001] [Indexed: 05/23/2023]
Abstract
The magnetism of epitaxial ultrathin films of Fe on ZnSe(001) has been investigated by x-ray magnetic circular dichroism down to the submonolayer regime. In contrast to other metallic ferromagnet/semiconductor interfaces, no reduction of the Fe magnetic moment was found at the Fe/ZnSe(001) interface. Furthermore, a significant enhancement of the Fe magnetic moment compared to the bulk value was observed for coverages up to one monolayer in agreement with theoretical predictions. We also demonstrate that the magnetic properties of the Fe/ZnSe(001) interface remain stable against thermal annealing up to 300 degrees C, a prerequisite for the future development of efficient spintronics devices.
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Affiliation(s)
- M Marangolo
- LMCP, Laboratoire de Minéralogie-Cristallographie, Universités Paris 6 et Paris 7, CNRS UMR 7590, 4 Place Jussieu, 75252 Paris Cedex 05, France
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24
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Abstract
Detergent-stable multimers of alpha-synuclein have been found specifically in the brains of patients with Parkinson's disease and other neurodegenerative diseases. Here we show that recombinant alpha-synuclein forms multimers in vitro upon exposure to vesicles containing certain polyunsaturated fatty acid (PUFA) acyl groups, including arachidonoyl and docosahexaenoyl. This process occurs at physiological concentrations and much faster than in aqueous solution. PUFA-induced aggregation involves physical association with the vesicle surface via the large apolipoprotein-like lipid-binding domain that constitutes the majority of the protein. beta- and gamma-synucleins, as well as the Parkinson's disease-associated alpha-synuclein variants A30P and A53T, show similar tendencies to multimerize in the presence of PUFAs. Multimerization does not require the presence of any tyrosine residues in the sequence. The membrane-based interaction of the synucleins with specific long chain polyunsaturated phospholipids may be relevant to the protein family's physiological functions and may also contribute to the aggregation of alpha-synuclein observed in neurodegenerative disease.
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Affiliation(s)
- R J Perrin
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, Illinois 61801, USA
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25
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Payton JE, Perrin RJ, Clayton DF, George JM. Protein-protein interactions of alpha-synuclein in brain homogenates and transfected cells. Brain Res Mol Brain Res 2001; 95:138-45. [PMID: 11687285 DOI: 10.1016/s0169-328x(01)00257-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
alpha-Synuclein is a highly conserved presynaptic protein with probable roles in normal synaptic development and plasticity as well as neurodegenerative disease, although its molecular function is not yet clear. To identify potential protein binding partners of alpha-synuclein, we performed co-immunoprecipitations using a monoclonal antibody (H3C) against its C-terminus. More than 20 detectable proteins were specifically co-immunoprecipitated from zebra finch and mouse forebrain extracts. One of these, with relative mobility of 55 kDa, was identified through microsequencing as a mixture of alpha- and beta-tubulin. Tubulin was specifically recovered from a mouse forebrain cytosolic extract by a GST/alpha-synuclein fusion protein immobilized on glutathione-Sepharose beads. In the converse experiment, alpha-synuclein bound to a column prepared from purified bovine brain tubulin immobilized upon CNBr-Sepharose. alpha-Synuclein does not appear to bind assembled microtubules, however, as alpha-synuclein did not pellet with polymerized microtubules in a standard assay for microtubule-associated proteins. Likewise, when a fusion construct of alpha-synuclein and green fluorescent protein (GFP) was expressed in African green monkey kidney epithelial (CV-1) cells, the fusion protein did not colocalize with endogenous microtubules. We conclude that alpha-synuclein may interact specifically with heterodimeric tubulin, but not microtubules, in the neuronal cytosol.
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Affiliation(s)
- J E Payton
- B107 Chemical and Life Science Laboratory, Department of Cell and Structural Biology, University of Illinois, Urbana, IL, USA
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26
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Abstract
This study adopted an interactional approach to understanding how 2 of the Five-Factor traits, openness to experience and conscientiousness, are related to creative behavior in the workplace. Openness to experience is theorized to result in high levels of creative behavior and conscientiousness is theorized to result in low levels of creative behavior when the situation allows for the manifestation of the trait influences. More specifically, the authors hypothesized that openness to experience would result in high levels of creative behavior if feedback valence were positive and job holders were presented with a heuristic task that allowed them to be creative. The authors also hypothesized that conscientiousness would result in low levels of creative behavior if supervisors engaged in close monitoring and coworkers were unsupportive. The authors tested their hypotheses in a sample of office workers, and 5 out of the 6 hypotheses were supported.
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Affiliation(s)
- J M George
- Jesse H Jones Graduate School of Management and Department of Psychology, Rice University, Houston, Texas 77005-1892, USA.
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27
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Perrin RJ, Woods WS, Clayton DF, George JM. Interaction of human alpha-Synuclein and Parkinson's disease variants with phospholipids. Structural analysis using site-directed mutagenesis. J Biol Chem 2000; 275:34393-8. [PMID: 10952980 DOI: 10.1074/jbc.m004851200] [Citation(s) in RCA: 315] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
alpha-Synuclein has been centrally implicated in neurodegenerative disease, and a normal function in developmental synaptic plasticity has been suggested by studies in songbirds. A variety of observations suggest the protein partitions between membrane and cytosol, a behavior apparently conferred by a conserved structural similarity to the exchangeable apolipoproteins. Here we show that the capacity to bind lipids is broadly distributed across exons 3, 4, and 5 (encoding residues 1-102). Binding to phosphatidylserine-containing vesicles requires the presence of all three exons, while binding to phosphatidic acid can be mediated by any one of the three. Consistent with a "class A2" helical binding mechanism, lipid association is disrupted by introduction of charged residues along the hydrophobic face of the predicted alpha-helix and also by biotinylation of conserved lysines (which line the interfacial region). Circular dichroism spectroscopy reveals a general correlation between the amount of lipid-induced alpha-helix content and the degree of binding to PS-containing vesicles. Two point mutations associated with Parkinson's disease have little (A30P) or no (A53T) effect on lipid binding or alpha-helicity. These results are consistent with the hypothesis that alpha-synuclein's normal functions depend on an ability to undergo a large conformational change in the presence of specific phospholipids.
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Affiliation(s)
- R J Perrin
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, Illinois 61801, USA
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28
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Clayton DF, George JM. Synucleins in synaptic plasticity and neurodegenerative disorders. J Neurosci Res 1999; 58:120-9. [PMID: 10491577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Synucleins are small highly conserved proteins in vertebrates, especially abundant in neurons and typically enriched at presynaptic terminals. Three genes in humans produce closely related synuclein proteins, all of which share a large amphipathic domain capable of reversible binding to lipid vesicles. Alpha synuclein has been specifically implicated in neurodegenerative disease. Two point mutations are genetically linked to familial Parkinson's disease, and alpha synuclein appears to form the major fibrillary component of Lewy bodies. Alpha synuclein also contributes to the intracellular inclusions of multiple system atrophy, and a fragment has been found in senile plaques in Alzheimer's disease. Although their normal cellular functions are unknown, several observations suggest the synucleins may serve to integrate presynaptic signaling and membrane trafficking. Alpha synuclein has been identified as a potent and selective inhibitor of phospholipase D2, which produces phosphatidic acid (to which synuclein binds) and is believed to function in the partitioning of membranes between the cell surface and intracellular stores. We outline a hypothesis whereby synuclein supports localized, experience-dependent turnover of synaptic membranes. Such a process may be important for lifelong learning and memory functions and may be especially vulnerable to disruption in aging-associated neurodegenerative diseases.
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Affiliation(s)
- D F Clayton
- Department of Cell and Structural Biology, University of Illinois, Urbana, USA
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29
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Abstract
One hundred and twenty ASA I and II grade children aged 2-9 years scheduled for outpatient dental extractions under general anaesthesia were studied. They were allocated randomly to one of three groups for airway management: group R had anaesthesia with a reinforced laryngeal mask airway, group L with a standard laryngeal mask airway and group N with a nasal mask. Anaesthesia was induced in all children using halothane in 50% nitrous oxide with oxygen and maintained on halothane in 67% nitrous oxide with oxygen. An Ayre's T-piece with Jackson-Rees modification was used. The incidence of airway obstruction was significantly lower and surgical access significantly better with the reinforced laryngeal mask airway when compared with the standard laryngeal mask airway. However, the reinforced laryngeal mask airway was significantly more difficult to insert when compared with the standard laryngeal mask airway. On comparing the reinforced laryngeal mask airway with the nasal mask, there were significantly fewer episodes of airway obstruction, better oxygen saturation, less increase in heart rate and fewer arrhythmias in the reinforced laryngeal mask airway group. Total time for the procedures was the same for all three groups. Thus, the reinforced laryngeal mask airway was found to be a favourable alternative to the standard laryngeal mask airway and nasal mask for paediatric outpatient dental extractions.
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Affiliation(s)
- J M George
- Department of Anaesthesia and Surgical Intensive Care, Singapore General Hospital, Republic of Singapore
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30
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Abstract
Synuclein proteins are produced, in vertebrates, by three genes. They share structural resemblance to apolipoproteins, but are abundant in the neuronal cytosol and present in enriched amounts at presynaptic terminals. Synucleins have been specifically implicated in three diseases:Alzheimer's (AD), Parkinson's (PD) and breast cancer. In AD, a peptide derived from alpha-synuclein forms an intrinsic component of plaque amyloid. In PD, an alpha-synuclein allele is genetically linked to several independent familial cases, and the protein appears to accumulate in Lewy bodies. In breast cancer, increased expression of gamma-synuclein correlates with disease progression. In songbirds, alpha-synuclein expression is correlated with plasticity in the developing song control system. Although the normal function of synucleins is unknown, a role in membrane plasticity seems likely.
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Affiliation(s)
- D F Clayton
- Beckman Institute and Dept of Cell and Structural Biology, The University of Illinois, Urbana 61801, USA
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31
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Abstract
alpha-Synuclein is a highly conserved presynaptic protein of unknown function. A mutation in the protein has been causally linked to Parkinson's disease in humans, and the normal protein is an abundant component of the intraneuronal inclusions (Lewy bodies) characteristic of the disease. alpha-Synuclein is also the precursor to an intrinsic component of extracellular plaques in Alzheimer's disease. The alpha-synuclein sequence is largely composed of degenerate 11-residue repeats reminiscent of the amphipathic alpha-helical domains of the exchangeable apolipoproteins. We hypothesized that alpha-synuclein should associate with phospholipid bilayers and that this lipid association should stabilize an alpha-helical secondary structure in the protein. We report that alpha-synuclein binds to small unilamellar phospholipid vesicles containing acidic phospholipids, but not to vesicles with a net neutral charge. We further show that the protein associates preferentially with vesicles of smaller diameter (20-25 nm) as opposed to larger (approximately 125 nm) vesicles. Lipid binding is accompanied by an increase in alpha-helicity from 3% to approximately 80%. These observations are consistent with a role in vesicle function at the presynaptic terminal.
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Affiliation(s)
- W S Davidson
- Department of Biochemistry, University of Illinois, Urbana, Illinois 61801, USA
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32
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Irizarry MC, Growdon W, Gomez-Isla T, Newell K, George JM, Clayton DF, Hyman BT. Nigral and cortical Lewy bodies and dystrophic nigral neurites in Parkinson's disease and cortical Lewy body disease contain alpha-synuclein immunoreactivity. J Neuropathol Exp Neurol 1998; 57:334-7. [PMID: 9600226 DOI: 10.1097/00005072-199804000-00005] [Citation(s) in RCA: 281] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A mutation in the alpha-synuclein gene has recently been linked to some cases of familial Parkinson's disease (PD). We characterized the expression of this presynaptic protein in the midbrain, striatum, and temporal cortex of control, PD, and dementia with Lewy bodies (DLB) brain. Control brain showed punctate pericellular immunostaining. PD brain demonstrated alpha-synuclein immunoreactivity in nigral Lewy bodies, pale bodies and abnormal neurites. Rare neuronal soma in PD brain were immunoreactive for alpha-synuclein. DLB cases demonstrated these findings as well as alpha-synuclein immunoreactivity in cortical Lewy bodies and CA2-3 neurites. These results suggest that, even in sporadic cases, there is an early and direct role for alpha-synuclein in the pathogenesis of PD and the neuropathologically related disorder DLB.
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Affiliation(s)
- M C Irizarry
- Alzheimer's Disease Research Unit, Massachusetts General Hospital-East, Charlestown 02129, USA
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Seid CA, Ramachandran RK, George JM, Govindarajan V, González-Rimbau MF, Flytzanis CN, Tomlinson CR. An extracellular matrix response element in the promoter of the LpS1 genes of the sea urchin Lytechinus pictus. Nucleic Acids Res 1997; 25:3175-82. [PMID: 9224621 PMCID: PMC146864 DOI: 10.1093/nar/25.15.3175] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The extracellular matrix (ECM) has been shown to play an important role in development and tissue-specific gene expression, yet the mechanism by which genes receive signals from the ECM is poorly understood. The aboral ectoderm-specific LpS1-alpha and -beta genes of Lytechinus pictus , members of the Spec gene family, provide an excellent model system to study ECM- mediated gene regulation. Disruption of the ECM by preventing collagen deposition using the lathrytic agent beta-aminopropionitrile (BAPN) inhibits LpS1 gene transcription. LpS1 transcription resumes after removal of BAPN and subsequent collagen reformation. Using a chloramphenicol acetyltransferase (CAT) reporter gene assay, we show that a 125 bp region of the LpS1-beta promoter from -108 to +17 contains an ECM response element (ECM RE). Insertion of the 125 bp region into the promoter of the metallothionein gene of L. pictus, a gene unaffected by ECM disruption, caused the fused promoter to become ECM dependent. As with the endogenous LpS1 genes, CAT activity directed by the fused LpS1-beta promoter resumed in embryos recovered from ECM disruption. A mutation in a cis -acting element called the proximal G-string, which lies in the 125 bp region, caused CAT activity levels in ECM-disrupted embryos to equal that of the wild-type LpS1-bet apromoter in ECM-intact embryos. These results suggest that the intact ECM normally transmits signals to inhibit repressor activity at the proximal G-string in aboral ectoderm cells. Consistent with these results were our findings which showed that in addition to expression in the aboral ectoderm, the proximal G-string mutation caused expression of the CAT gene in oral ectoderm cells. These studies suggested that the proximal G-string serves as a binding site for negative regulation of the LpS1 genes in oral ectoderm during development. We also examined trans -acting factors binding the proximal G-string following ECM disruption. Band shift gels revealed a predominant set of slower migrating nuclear proteins from ECM-disrupted embryos which bound the proximal G-string. This work suggested that ECM disruption initiates signaling that induces a repressor to bind the ECM RE and/or modifies ECM RE binding proteins, which in turn represses LpS1 gene activity.
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Affiliation(s)
- C A Seid
- Department of Biology, University of Houston, Houston, TX 77204-5513, USA
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Withers GS, George JM, Banker GA, Clayton DF. Delayed localization of synelfin (synuclein, NACP) to presynaptic terminals in cultured rat hippocampal neurons. Brain Res Dev Brain Res 1997; 99:87-94. [PMID: 9088569 DOI: 10.1016/s0165-3806(96)00210-6] [Citation(s) in RCA: 170] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Synelfin is a presynaptic protein of unknown function that is differentially regulated in the avian song control circuit during the critical period for song learning; in humans, it gives rise to an amyloidogenic peptide found in senile plaques of Alzheimer's disease. To gain insight into the potential involvement of synelfin in synapse development, we investigated its expression in neurons cultured from the embryonic rat hippocampus. These neurons express a variety of defined synaptic proteins, and form numerous synaptic connections after several days in culture. Synapsin I, a synaptic vesicle-associated protein, was detected within one day after the neurons were put in culture, but significant immunoreactivity for synelfin was not detected until approximately 5 days in vitro (DIV). By 3 DIV, synapsin-positive puncta (previously shown to correspond to presynaptic specializations) were detected surrounding the soma and proximal dendritic processes, whereas comparable aggregations of synelfin did not appear until several days later. By 14 DIV the punctate concentrations of synelfin and synapsin overlapped completely. Thus synelfin is expressed in these cultured neurons and eventually becomes localized to presynaptic terminals, but it is absent from these specializations when they first form. We conclude that presynaptic terminals can change in molecular composition, and that synelfin is associated with later stages in synaptic development or modulation.
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Affiliation(s)
- G S Withers
- Dept. of Neuroscience, University of Virginia, Charlottesville, USA
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35
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Seid CA, George JM, Sater AK, Kozlowski MT, Lee H, Govindarajan V, Ramachandran RK, Tomlinson CR. USF in the Lytechinus sea urchin embryo may act as a transcriptional repressor in non-aboral ectoderm cells for the cell lineage-specific expression of the LpS1 genes. J Mol Biol 1996; 264:7-19. [PMID: 8950263 DOI: 10.1006/jmbi.1996.0619] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [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: 02/03/2023]
Abstract
Expression of the aboral ectoderm-specific LpS1 gene in Lytechinus was used to study lineage-specific transcriptional regulation during sea urchin development. Band shift assays using anti-USF antibody showed that a USF-like protein bound the USF core sequence 5'-CACGTG-3' in the promoter of the LpS1 gene. DNA constructs consisting of a wild-type LpS1 promoter and the same LpS1 promoter with a mutated USF binding site fused to the bacterial chloramphenicol acetyltransferase reporter gene were tested. The mutation in the USF binding site caused an increase in chloramphenicol acetyltransferse activity. We selected a clone that encodes USF, LvUSF, from a gastrula-stage cDNA library representing Lytechinus variegatus. Transactivation experiments, in which LvUSF RNA or a DNA construct consisting of the LvUSF cDNA clone fused to the Lytechinus pictus metallothionein promoter coinjected with the wild-type or mutated LpS1 promoter-chloramphenicol acetyltransferase gene construct, showed that chloramphenicol acetyltransferase activity from the wild-type construct was repressed, while the construct mutated at the USF binding site was active. The same wild-type and mutated LpS1 promoter DNA fragments ligated to the green fluorescent protein reporter gene were used to examine spatial expression. The reporter gene constructs containing the mutated USF binding site were expressed inappropriately in all cell types including the gut and oral ectoderm in gastrula and larva stage embryos, while the wild-type constructs were expressed primarily in the aboral ectoderm. USF was expressed in all cells of the early embryo and in all tissues except the aboral ectoderm in later embryos. The data are consistent with a model depicting Lytechinus USF, as a temporal and spatial regulator by repressing LpS1 gene transcription in non-aboral ectoderm cells.
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Affiliation(s)
- C A Seid
- Department of Biology, University of Houston, TX 77204-5513, USA
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George JM, Seid CA, Lee H, Tomlinson CR. Two distinct forms of USF in the Lytechinus sea urchin embryo do not play a role in LpS1 gene inactivation upon disruption of the extracellular matrix. Mol Reprod Dev 1996; 45:1-9. [PMID: 8873063 DOI: 10.1002/(sici)1098-2795(199609)45:1<1::aid-mrd1>3.0.co;2-o] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [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: 02/02/2023]
Abstract
Recent studies in our laboratory indicated that the upstream stimulatory factor (USF) in the sea urchin embryo of Lytechinus acts as a transcriptional repressor for the aboral ectoderm-specific expression of the LpS1 genes. Disruption of the extracellular matrix (ECM) arrests development prior to gastrulation and inactivates the LpS1 genes. We wanted to determine whether the inactivation of the LpS1 genes by ECM disruption may be due to an increase in USF expression. In the course of the investigation, a second L, variegatus USF cDNA clone (LvUSF2) was isolated and sequenced. The deduced amino acid sequence of LvUSF2 is nearly identical to LvUSF1 except at the amino end, where they are sharply divergent. Like LvUSF1, LvUSF2 has a USF-specific, a basic/hefixloop-helix, and a leucine zipper domain. Genomic DNA blots indicated that the two cDNA clones are derived from one gene, which suggested that the Lytechinus USF1 and USF2 mRNAs, of approximately 6.0 and 4.0 kb, respectively, are the result of differential RNA splicing. ECM disruption in Lytechinus embryos caused a relative drop in USF RNA accumulation levels to approximately 60% of control embryos, while LpS1 RNA accumulation levels dropped to less than 5%. USF protein levels and DNA binding activities in ECM-disrupted embryos also dropped to approximately 60% to that of control embryos. A mutation at the USF binding site in an LpS1 promoter-chloramphenicol acetyl transferase (CAT) fusion DNA construct did not cause a relative increase in CAT activity in ECM disrupted embryos. These results suggest that the induced drop in LpS1 gene expression by ECM disruption is not due to an increase in the repressive activity of USF.
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Affiliation(s)
- J M George
- Department of Biology, University of Houston, Texas 77204-5513, USA
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Irizarry MC, Kim TW, McNamara M, Tanzi RE, George JM, Clayton DF, Hyman BT. Characterization of the precursor protein of the non-A beta component of senile plaques (NACP) in the human central nervous system. J Neuropathol Exp Neurol 1996; 55:889-95. [PMID: 8759778 DOI: 10.1097/00005072-199608000-00004] [Citation(s) in RCA: 157] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A novel and highly conserved presynaptic protein has been independently described in rodents (synuclein/SYN-1), songbirds (synelfin), and humans (the precursor protein of the non-A beta component of senile plaques, NACP); a fragment of the latter has been detected in senile plaques in Alzheimer's disease (AD). We characterized the expression of NACP in human AD and non-AD brain. A subcellular fractionation study demonstrated that NACP was mainly localized to cytosolic fractions of human temporal cortex. NACP was also detectable in various membrane and vesicular fractions, suggesting that the protein was associated with membrane structures including synaptic vesicles. Pericellular immunostaining of the neuropil was observed in neocortical and limbic regions, supporting a synaptic localization. Senile plaques in AD brains were not immunoreactive, and confocal microscopy suggested a loss of NACP immunoreactivity in cored plaques. No difference was found in the amount of protein in AD and control frontal cortex, as measured by immunoblotting. PCR analysis showed that the full-length mRNA product was the major splice form in both AD and control human brains. Thus, despite the association of a hydrophobic fragment of NACP with senile plaques, our data suggest that the precursor itself is not a significant component of plaques and NACP synthesis is not substantially altered in AD. Nevertheless, the protein is an abundant component of synaptic regions prone to degeneration in AD, and may have a role in the expression or advancement of the disease.
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Affiliation(s)
- M C Irizarry
- Neurology Service, Massachusetts General Hospital, Boston 02114, USA
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George JM, Jones GR. The experience of work and turnover intentions: interactive effects of value attainment, job satisfaction, and positive mood. J Appl Psychol 1996; 81:318-25. [PMID: 8690691 DOI: 10.1037/0021-9010.81.3.318] [Citation(s) in RCA: 165] [Impact Index Per Article: 5.9] [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: 02/01/2023] Open
Abstract
The researchers proposed that the phenomenological experience of work is multifaceted and that simultaneously considering the combined effects of the different aspects of the work experience holds considerable promise for increasing understanding of turnover intentions and other organizationally relevant outcomes. Research in subjective well-being and other areas suggests that there are 3 important aspects of the experience of work: attainment of values, attitudes, and moods. It was hypothesized and found that the relationship between job satisfaction and turnover intentions is jointly moderated by value attainment and positive mood. The nature of this triple interaction was such that the job satisfaction-turnover intention relationship was strongest when workers' jobs did not help them to attain terminal values and positive moods were experienced, and the relationship was weakest when jobs helped workers to attain terminal values and positive moods were experienced.
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Affiliation(s)
- J M George
- Department of Management, College of Business Administration, Texas A&M University, College Station 77843-4221, USA
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Govindarajan V, Ramachandran RK, George JM, Shakes DC, Tomlinson CR. An ECM-bound, PDGF-like growth factor and a TGF-alpha-like growth factor are required for gastrulation and spiculogenesis in the Lytechinus embryo. Dev Biol 1995; 172:541-51. [PMID: 8612970 DOI: 10.1006/dbio.1995.8059] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [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: 01/31/2023]
Abstract
Growth factors and the extracellular matrix have been shown to fulfill vital developmental roles in many embryonic systems. Our hypothesis is that a developmental role played by the extracellular matrix in sea urchins may be the binding of a PDGF-like growth factor to promote signaling activity. We report here that anti-human PDGF-B antibodies and anti-human TGF-alpha antibodies immunoprecipitated specific proteins isolated from Lytechinus embryos. Addition of these antibodies to Lytechinus embryos inhibited gastrulation and spiculogenesis. The embryos are sensitive to the antibodies from the four-cell through the hatching blastula stages, which suggests that the TGF-alpha-like and PDGF-like ligands are required for the early differentiation of the gut and spicules. We present evidence that the PDGF-like growth factor depends on the extracellular matrix for signaling activity. Synthetic peptides representing the heparan sulfate proteoglycan binding sequence on human PDGF-B were added to Lytechinus embryo cultures to compete for binding sites with the endogenous PDGF-like growth factor. The experimental peptide inhibited gastrulation and caused radially arranged multiple spicules to form. Development was unaffected by a control peptide. These studies support our hypothesis and suggest that TGF-alpha-like and PDGF-like growth factors induce signaling events required for sea urchin gastrulation and spiculogenesis and suggest that an extracellular matrix-associated PDGF-like growth factor is involved in differentiation along the oral-aboral axis.
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Affiliation(s)
- V Govindarajan
- Department of Biology, University of Houston, Texas 77204-5513, USA
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George JM, Nair L, Dhara SS. Postoperative hypoxaemia during transport and in the recovery area. Ann Acad Med Singap 1995; 24:807-11. [PMID: 8838985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This study was undertaken to ascertain the incidence of postoperative hypoxaemia in the recovery area and during transfer to the recovery area while adhering to the current practice of anaesthesia and recovery room care. Attempts were also made to determine some of the risk factors for the development of hypoxaemia. There were 546 patients who had general or regional anaesthesia observed in the recovery area and of these, 534 patients were also observed during transfer using Critikon Oxyshuttle pulse oximeters. The incidence of hypoxaemia (SpO2 < or = 90%) and severe hypoxaemia (SpO2 < or = 85%) during transfer were 10.11% and 2.06% respectively. The incidence of hypoxaemia and severe hypoxaemia in the recovery area were 8.42% and 2.2% respectively. No oxygen was given to patients during transfer. In the recovery area, 322 patients (58.97%) had oxygen therapy and 224 patients (41.03%) did not. The occurrence of hypoxaemia during transfer was significantly related to the duration of surgery. In the recovery area, age and weight were found to be statistically significant risk factors. The incidence of hypoxaemia in this study is much lower than that reported in other studies.
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Affiliation(s)
- J M George
- Department of Anaesthesia and Surgical Intensive Care, Singapore General Hospital
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Wallace CS, Withers GS, Weiler IJ, George JM, Clayton DF, Greenough WT. Correspondence between sites of NGFI-A induction and sites of morphological plasticity following exposure to environmental complexity. Brain Res Mol Brain Res 1995; 32:211-20. [PMID: 7500832 DOI: 10.1016/0169-328x(95)00076-5] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
To determine if gene regulation may play a role in behaviorally-induced morphological plasticity in the brain, we used in situ hybridization to measure levels of mRNA for the immediate early gene transcription factor NGFI-A (also known as ZENK, zif/268, egr-1 and Krox 24). Brains of periadolescent male rats exposed to 2-4 days of the following behavioral treatments were compared: (1) group housing in a complex environment (EC); (2) individual housing with daily handling (HIC); and (3) individual handling (IC). Quantitative analysis of the autoradiograms revealed that EC rats had significantly higher levels of NGFI-A than IC rats in regions of cortex previously shown to exhibit morphological plasticity (most pronounced in visual cortex), but not in frontal cortex where no dendritic changes have been detected. HIC rats were intermediate between the two groups. These data support an association between structural plasticity and altered patterns of immediate early gene expression.
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Affiliation(s)
- C S Wallace
- Neuroscience Program, University of Illinois, Urbana 61801, USA
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Abstract
A male zebra finch learns a song by listening to a tutor, but song learning is normally restricted to a critical period in juvenile development. Here we identify an RNA whose expression in the song control circuit is altered during this critical period. The RNA encodes a soluble presynaptic protein that forms a predicted amphipathic alpha helix typical of the lipid-binding domain in apolipoproteins. We show this protein, which we call synelfin, to be the homolog of the human non-A beta component (and its precursor) recently purified from Alzheimer's disease amyloid. We suggest this highly conserved protein may serve a novel function critical to the regulation of vertebrate neural plasticity.
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Affiliation(s)
- J M George
- Department of Cell and Structural Biology, Beckman Institute, University of Illinois, Urbana 61801, USA
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George JM, Wagner EE. Correlations between the Hand Test Pathology score and Personality Assessment Inventory scales for pain clinic patients. Percept Mot Skills 1995; 80:1377-8. [PMID: 7478899 DOI: 10.2466/pms.1995.80.3c.1377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 01/25/2023]
Abstract
Pearson correlations between the Hand Test Pathology (PATH) score and Personality Assessment Inventory scales produced a cluster of relationships characteristic of an antisocial orientation. Likewise, PATH significantly differentiated between a "P" (Pathology) group flagged by a high Negative Impression score on the inventory, and an "N" (Normal) group of 100 pain patients. It was suggested that the interpretive simplicity of Hand Test scores renders the scores amenable to further correlational studies involving the inventory.
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Nastiuk KL, Mello CV, George JM, Clayton DF. Immediate-early gene responses in the avian song control system: cloning and expression analysis of the canary c-jun cDNA. Brain Res Mol Brain Res 1994; 27:299-309. [PMID: 7898314 DOI: 10.1016/0169-328x(94)90013-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Previous studies have shown that song presentation results in a rapid rise in mRNA levels for the ZENK gene (the avian homologue of zif-268, Egr-1, NGFI-A, and Krox-24) in specific parts of the songbird forbrain. Metrazole-induced seizures also cause an increase in ZENK mRNA, even more widely throughout the telencephalon. Surprisingly, however, little or no ZENK induction by either stimulus was observed in several forebrain areas involved in auditory processing and song production. To learn whether this pattern of regulation is specific to ZENK, we examined the response of another 'immediate-early' gene, c-jun. Here we first describe the identification, cloning and sequence analysis of a canary cDNA encoding c-jun. Then, by in situ hybridization we show that c-jun is also induced by song or seizure, and in a pattern mostly similar to ZENK. As with ZENK, no induction of c-jun is observed in the androgen receptor-containing song nuclei or within the primary thalamo-recipient auditory area of the forebrain. Thus common immediate early gene responses appear to be selectively uncoupled from physiological activation in these specific forebrain regions, which are also characterized by tight developmental, hormonal and seasonal regulation.
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Affiliation(s)
- K L Nastiuk
- Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, NY 10021
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George JM, Pereira LG, Barthélémy A, Petroff F, Steren L, Duvail JL, Fert A, Loloee R, Holody P, Schroeder PA. Inverse spin-valve-type magnetoresistance in spin engineered multilayered structures. Phys Rev Lett 1994; 72:408-411. [PMID: 10056423 DOI: 10.1103/physrevlett.72.408] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Burke MJ, Brief AP, George JM. The role of negative affectivity in understanding relations between self-reports of stressors and strains: a comment on the applied psychology literature. J Appl Psychol 1993; 78:402-12. [PMID: 8331024 DOI: 10.1037/0021-9010.78.3.402] [Citation(s) in RCA: 266] [Impact Index Per Article: 8.6] [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: 01/29/2023] Open
Abstract
On the basis of a brief review of the health, organizational, and personality psychology literatures supportive of the expectation that observed relations between self-reports of stressors and strains are influenced by the mood-dispositional dimension negative affectivity (NA), reanalyses of four data sets were conducted. The results of these reanalyses, contrary to the assertions of several authors in the applied psychology literature, offered further support for the hypothesized "nuisance" properties of NA in studies involving relations between self-reports of stressors and strain. A discussion of how NA and other mood-dispositional dimensions may be of interest to investigators concerned with relations between self-reports of any condition of employment and any affective state of workers is presented.
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Affiliation(s)
- M J Burke
- Department of Psychology, Tulane University, New Orleans, Louisiana 70118-5698
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Abstract
As a means of integrating bottom-up and top-down theories of subjective well-being (SWB), a framework was proposed that, in part, posits that both objective life circumstances and global personality dimensions indirectly affect SWB through their effects on the interpretation of life circumstances. This proposition was tested both cross-sectionally and longitudinally among a sample of approximately 375 men and women. Personality was operationalized in terms of the dispositional trait negative affectivity (NA), and the life circumstance investigated was health. Strong support was obtained for the hypothesized indirect effects of NA and objective health on SWB. Implications of the integrative framework for the study of SWB are discussed.
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Affiliation(s)
- A P Brief
- Freeman School of Business, Tulane University, New Orleans, Louisiana 70118-5669
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Abstract
As a means of integrating bottom-up and top-down theories of subjective well-being (SWB), a framework was proposed that, in part, posits that both objective life circumstances and global personality dimensions indirectly affect SWB through their effects on the interpretation of life circumstances. This proposition was tested both cross-sectionally and longitudinally among a sample of approximately 375 men and women. Personality was operationalized in terms of the dispositional trait negative affectivity (NA), and the life circumstance investigated was health. Strong support was obtained for the hypothesized indirect effects of NA and objective health on SWB. Implications of the integrative framework for the study of SWB are discussed.
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Affiliation(s)
- A P Brief
- Freeman School of Business, Tulane University, New Orleans, Louisiana 70118-5669
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Mauriello SM, George JM, May KN. Pre-admission credentials and dental school performance of dental hygienists. J Dent Educ 1993; 57:306-11. [PMID: 8482741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This study examined the effect of dental hygiene preparation prior to entering dental school on dental school performance. Study participants included 203 female students who entered a public dental school from 1980-1989. Groups 1 and 2 had completed dental school prerequisites and a dental hygiene curriculum in a community college setting (n = 19) or university setting (n = 22) respectively, and Group 3 (n = 162) were traditional students with no dental hygiene education. Preadmission variables were predental science and non-science grade point averages (GPA) and Dental Admission Test (DAT) scores. Performance variables were GPA of years one and two of dental school and National Board scores (Part 1). Results showed that Group 2 hygienists had significantly lower predental science GPAs than Group 1 or 3 and significantly lower non-science GPAs than Group 3 (p < 0). Both groups of hygienists had significantly lower DAT scores than Group 3 (p < 0). No difference was seen in first and second year GPAs or the National Board average. Adjusting performance scores to compensate for deficiencies in preadmission variables showed that Group 2 hygienists had significantly higher adjusted first-year GPAs and National Board averages than Group 3 (p < 0). Thus, hygienists performed as well as non-hygienists in spite of weaker admission credentials.
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Affiliation(s)
- S M Mauriello
- Department of Dental Ecology, School of Dentistry, University of North Carolina, Chapel Hill 27599-7450
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George JM, Reed TF, Ballard KA, Colin J, Fielding J. Contact with AIDS patients as a source of work-related distress: effects of organizational and social support. Acad Manage J 1993; 36:157-171. [PMID: 10123743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this study, we hypothesized that a nurse's exposure to acquired immunodeficiency syndrome (AIDS) patients as part of the work role is positively associated with distress as indexed by negative mood at work. Given this expected relation, we sought to identify factors that might reduce the negative effects of caring for AIDS patients on nurses. We predicted that both organizational and social support would moderate the relationship between extent of exposure and negative mood, with the relationship being strongest when support is low and weakest when support is high. The results of tests among a sample of 256 nurses supported all the hypotheses. We discuss implications of this study and directions for future research.
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Affiliation(s)
- J M George
- Department of Management, Texas A&M University
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