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Li Z, Yin Q, Lv W, Shen J, Wang S, Zhao T, Cai J, Lei H, Lin SZ, Zhang Y, Shen B. Electron-Assisted Generation and Straight Movement of Skyrmion Bubble in Kagome TbMn 6Sn 6. Adv Mater 2024; 36:e2309538. [PMID: 38366361 DOI: 10.1002/adma.202309538] [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: 09/15/2023] [Revised: 12/31/2023] [Indexed: 02/18/2024]
Abstract
Topological magnetic textures are promising candidates as binary data units for the next-generation memory device. The precise generation and convenient control of nontrivial spin topology at zero field near room temperature endows the critical advantages in skyrmionic devices but is not simultaneously integrated into one material. Here, in the Kagome plane of quantum TbMn6Sn6, the expedient generation of the skyrmion bubbles in versatile forms of lattice, chain, and isolated one by converging the electron beam, where the electron intensity gradient contributes to the dynamic generation from local anisotropy variation near spin reorientation transition (SRT) is reported. Encouragingly, by utilizing the dynamic shift of the SRT domain interface, the straight movement is actualized with the skyrmion bubble slave to the SRT domain interface forming an elastic composite object, avoiding the usual deflection from the skyrmion Hall effect. The critical contribution of the SRT domain interface via conveniently electron-assisted heating is further theoretically validated in micromagnetic simulation, highlighting the compatible application possibility in advanced devices.
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Affiliation(s)
- Zhuolin Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Qiangwei Yin
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Wenxin Lv
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Jun Shen
- Department of Energy and Power Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Shouguo Wang
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Tongyun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Hechang Lei
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Shi-Zeng Lin
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Open Access Research Infrastrucure, Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, 315201, China
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2
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He Z, Li Z, Chen Z, Wang Z, Shen J, Wang S, Song C, Zhao T, Cai J, Lin SZ, Zhang Y, Shen B. Experimental observation of current-driven antiskyrmion sliding in stripe domains. Nat Mater 2024:10.1038/s41563-024-01870-8. [PMID: 38605194 DOI: 10.1038/s41563-024-01870-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 03/18/2024] [Indexed: 04/13/2024]
Abstract
Magnetic skyrmions are promising as next-generation information units. Their antiparticle-the antiskyrmion-has also been discovered in chiral magnets. Here we experimentally demonstrate antiskyrmion sliding in response to a pulsed electric current at room temperature without the requirement of an external magnetic field. This is realized by embedding antiskyrmions in helical stripe domains, which naturally provide one-dimensional straight tracks along which antiskyrmion sliding can be easily launched with low current density and without transverse deflection from the antiskyrmion Hall effect. The higher mobility of the antiskyrmions in the background of helical stripes in contrast to the typical ferromagnetic state is a result of intrinsic material parameters and elastic energy of the stripe domain, thereby smearing out the random pinning potential, as supported by micromagnetic simulations. The demonstration and comprehensive understanding of antiskyrmion movement along naturally straight tracks offers a new perspective for (anti)skyrmion application in spintronics.
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Affiliation(s)
- Zhidong He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhuolin Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhaohui Chen
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, China
| | - Zhan Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Jun Shen
- Department of Energy and Power Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing, China
| | - Shouguo Wang
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei, China
| | - Cheng Song
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing, China
| | - Tongyun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Shi-Zeng Lin
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA.
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
- Songshan Lake Materials Laboratory, Dongguan, China.
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, China
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3
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Pettine J, Padmanabhan P, Shi T, Gingras L, McClintock L, Chang CC, Kwock KWC, Yuan L, Huang Y, Nogan J, Baldwin JK, Adel P, Holzwarth R, Azad AK, Ronning F, Taylor AJ, Prasankumar RP, Lin SZ, Chen HT. Light-driven nanoscale vectorial currents. Nature 2024; 626:984-989. [PMID: 38326619 PMCID: PMC10901733 DOI: 10.1038/s41586-024-07037-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 01/05/2024] [Indexed: 02/09/2024]
Abstract
Controlled charge flows are fundamental to many areas of science and technology, serving as carriers of energy and information, as probes of material properties and dynamics1 and as a means of revealing2,3 or even inducing4,5 broken symmetries. Emerging methods for light-based current control5-16 offer particularly promising routes beyond the speed and adaptability limitations of conventional voltage-driven systems. However, optical generation and manipulation of currents at nanometre spatial scales remains a basic challenge and a crucial step towards scalable optoelectronic systems for microelectronics and information science. Here we introduce vectorial optoelectronic metasurfaces in which ultrafast light pulses induce local directional charge flows around symmetry-broken plasmonic nanostructures, with tunable responses and arbitrary patterning down to subdiffractive nanometre scales. Local symmetries and vectorial currents are revealed by polarization-dependent and wavelength-sensitive electrical readout and terahertz (THz) emission, whereas spatially tailored global currents are demonstrated in the direct generation of elusive broadband THz vector beams17. We show that, in graphene, a detailed interplay between electrodynamic, thermodynamic and hydrodynamic degrees of freedom gives rise to rapidly evolving nanoscale driving forces and charge flows under the extremely spatially and temporally localized excitation. These results set the stage for versatile patterning and optical control over nanoscale currents in materials diagnostics, THz spectroscopies, nanomagnetism and ultrafast information processing.
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Affiliation(s)
- Jacob Pettine
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA.
| | - Prashant Padmanabhan
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Teng Shi
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
| | | | - Luke McClintock
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
- Department of Physics, University of California, Davis, Davis, CA, USA
| | - Chun-Chieh Chang
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Kevin W C Kwock
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
- Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, USA
| | - Long Yuan
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Yue Huang
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - John Nogan
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, USA
| | - Jon K Baldwin
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
| | | | | | - Abul K Azad
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Filip Ronning
- Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Antoinette J Taylor
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Rohit P Prasankumar
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
- Intellectual Ventures, Bellevue, WA, USA
| | - Shi-Zeng Lin
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Hou-Tong Chen
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA.
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4
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Wan X, Sarkar S, Lin SZ, Sun K. Topological Exact Flat Bands in Two-Dimensional Materials under Periodic Strain. Phys Rev Lett 2023; 130:216401. [PMID: 37295089 DOI: 10.1103/physrevlett.130.216401] [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] [Received: 11/21/2022] [Accepted: 04/26/2023] [Indexed: 06/12/2023]
Abstract
We study flat bands and their topology in 2D materials with quadratic band crossing points under periodic strain. In contrast to Dirac points in graphene, where strain acts as a vector potential, strain for quadratic band crossing points serves as a director potential with angular momentum ℓ=2. We prove that when the strengths of the strain fields hit certain "magic" values, exact flat bands with C=±1 emerge at charge neutrality point in the chiral limit, in strong analogy to magic angle twisted-bilayer graphene. These flat bands have ideal quantum geometry for the realization of fractional Chern insulators, and they are always fragile topological. The number of flat bands can be doubled for certain point group, and the interacting Hamiltonian is exactly solvable at integer fillings. We further demonstrate the stability of these flat bands against deviations from the chiral limit, and discuss possible realization in 2D materials.
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Affiliation(s)
- Xiaohan Wan
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Siddhartha Sarkar
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Shi-Zeng Lin
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Kai Sun
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
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5
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Li Z, Yin Q, Jiang Y, Zhu Z, Gao Y, Wang S, Shen J, Zhao T, Cai J, Lei H, Lin SZ, Zhang Y, Shen B. Discovery of Topological Magnetic Textures near Room Temperature in Quantum Magnet TbMn 6 Sn 6. Adv Mater 2023; 35:e2211164. [PMID: 36856016 DOI: 10.1002/adma.202211164] [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: 11/29/2022] [Revised: 02/19/2023] [Indexed: 05/19/2023]
Abstract
The study of topology in quantum materials has fundamentally advanced the understanding in condensed matter physics and potential applications in next-generation quantum information technology. Recently, the discovery of a topological Chern phase in the spin-orbit-coupled Kagome lattice TbMn6 Sn6 has attracted considerable interest. Whereas these phenomena highlight the contribution of momentum space Berry curvature and Chern gap on the electronic transport properties, less is known about the intrinsic real space magnetic texture, which is crucial for understanding the electronic properties and further exploring the unique quantum behavior. Here, the stabilization of topological magnetic skyrmions in TbMn6 Sn6 using Lorentz transmission electron microscopy near room temperature, where the spins experience full spin reorientation transition between the a- and c-axes, is directly observed. An effective spin Hamiltonian based on the Ginzburg-Landau theory is constructed and micromagnetic simulation is performed to clarify the critical role of Ruderman-Kittel-Kasuya-Yosida interaction on the stabilization of skyrmion lattice. These results not only uncover nontrivial spin topological texture in TbMn6 Sn6 , but also provide a solid basis to study its interplay with electronic topology.
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Affiliation(s)
- Zhuolin Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Qiangwei Yin
- Laboratory for Neutron Scattering, Beijing Key Laboratory of Opto-Electronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China
| | - Yi Jiang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - ZhaoZhao Zhu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Yang Gao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Shouguo Wang
- School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Jun Shen
- Department of Energy and Power Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Tongyun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Hechang Lei
- Laboratory for Neutron Scattering, Beijing Key Laboratory of Opto-Electronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China
| | - Shi-Zeng Lin
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, 315201, China
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6
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Zhao X, Tang J, Pei K, Wang W, Lin SZ, Du H, Tian M, Che R. Current-Induced Magnetic Skyrmions with Controllable Polarities in the Helical Phase. Nano Lett 2022; 22:8793-8800. [PMID: 36331209 DOI: 10.1021/acs.nanolett.2c02061] [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: 06/16/2023]
Abstract
We report the current-induced creation of magnetic skyrmions in a chiral magnet FeGe nanostructure by using in situ Lorentz transmission electron microscopy. We show that magnetic skyrmions with controllable polarity can be transferred from the helical ground state simply by controlling the direction of the current flow at zero magnetic fields. The force analysis and symmetry consideration, backed up by micromagnetic simulations, well explain the experimental results, where magnetic skyrmions are created because of the edge instability of the helical state in the presence of spin-transfer torque. The on-demand generation of skyrmions and control of their polarity by electric current without the need for a magnetic field will enable novel purely electric-controlled skyrmion devices.
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Affiliation(s)
- Xuebing Zhao
- Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Department of Materials Science, Fudan University, Shanghai200438, China
| | - Jin Tang
- School of Physics and Optoelectronics Engineering Science, Anhui University, Hefei230601, China
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei230031, China
| | - Ke Pei
- Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Department of Materials Science, Fudan University, Shanghai200438, China
| | - Weiwei Wang
- School of Physics and Optoelectronics Engineering Science, Anhui University, Hefei230601, China
| | - Shi-Zeng Lin
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico87545, United States
| | - Haifeng Du
- School of Physics and Optoelectronics Engineering Science, Anhui University, Hefei230601, China
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei230031, China
| | - Mingliang Tian
- School of Physics and Optoelectronics Engineering Science, Anhui University, Hefei230601, China
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei230031, China
| | - Renchao Che
- Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Department of Materials Science, Fudan University, Shanghai200438, China
- Zhejiang Laboratory, Hangzhou311100, China
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7
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Li Z, Su J, Lin SZ, Liu D, Gao Y, Wang S, Wei H, Zhao T, Zhang Y, Cai J, Shen B. Field-free topological behavior in the magnetic domain wall of ferrimagnetic GdFeCo. Nat Commun 2021; 12:5604. [PMID: 34556648 PMCID: PMC8460835 DOI: 10.1038/s41467-021-25926-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 09/09/2021] [Indexed: 11/22/2022] Open
Abstract
Exploring and controlling topological textures such as merons and skyrmions has attracted enormous interests from the perspective of fundamental research and spintronic applications. It has been predicted theoretically and proved experimentally that the lattice form of topological meron-skyrmion transformation can be realized with the requirement of external magnetic fields in chiral ferromagnets. However, such topological transition behavior has yet to be verified in other materials. Here, we report real-space observation of magnetic topology transformation between meron pairs and skyrmions in the localized domain wall of ferrimagnetic GdFeCo films without the need of magnetic fields. The topological transformation in the domain wall of ferrimagnet is introduced by temperature-induced spin reorientation transition (SRT) and the underlying mechanism is revealed by micromagnetic simulations. The convenient electric-controlling topology transformation and driving motion along the confined domain wall is further anticipated, which will enable advanced application in magnetic devices. Merons and Skyrmions, two topological spin-textures, have attracted a lot of interests due to their potential use in information storage. Here, the authors demonstrate the transformation of Meron pairs into Skyrmions without an applied magnetic field within domain walls of GdFeCo films.
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Affiliation(s)
- Zhuolin Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Jian Su
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Shi-Zeng Lin
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Dan Liu
- Department of Physics, Beijing Technology and Business University, 100048, Beijing, China
| | - Yang Gao
- Institute of Advanced Materials, Beijing Normal University, 100875, Beijing, China
| | - Shouguo Wang
- Institute of Advanced Materials, Beijing Normal University, 100875, Beijing, China
| | - Hongxiang Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Tongyun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China. .,Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
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8
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Su Y, Lin SZ. Current-Induced Reversal of Anomalous Hall Conductance in Twisted Bilayer Graphene. Phys Rev Lett 2020; 125:226401. [PMID: 33315429 DOI: 10.1103/physrevlett.125.226401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 08/17/2020] [Accepted: 10/21/2020] [Indexed: 05/12/2023]
Abstract
It is observed experimentally that the sign of the Hall resistance can be flipped by a dc electric current in the twisted bilayer graphene (TBG) at 3/4 filling of the fourfold degenerate conduction flat bands. The experiment implies a switching of the valley polarization (VP) and topology in TBG. Here we present a theory on the current-induced switching of VP and topology. The presence of current in the bulk causes the redistribution of electron occupation in bands near the Fermi energy, which then deforms and shifts the band dispersion due to the Coulomb interaction. Above a critical current, the original occupied and empty bands can be swapped, resulting in the switching of VP and topology.
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Affiliation(s)
- Ying Su
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Shi-Zeng Lin
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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9
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Lin SZ, Kim DY, Bauer ED, Ronning F, Thompson JD, Movshovich R. Interplay of the Spin Density Wave and a Possible Fulde-Ferrell-Larkin-Ovchinnikov State in CeCoIn_{5} in Rotating Magnetic Field. Phys Rev Lett 2020; 124:217001. [PMID: 32530696 DOI: 10.1103/physrevlett.124.217001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
The d-wave superconductor CeCoIn_{5} has been proposed as a strong candidate for supporting the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state near the low-temperature boundary of its upper critical field. Neutron diffraction, however, finds spin-density-wave (SDW) order in this part of the phase diagram for field in the a-b plane, and evidence for the SDW disappears as the applied field is rotated toward the tetragonal c axis. It is important to understand the interplay between the SDW and a possible FFLO state in CeCoIn_{5}, as the mere existence of an SDW does not necessarily exclude an FFLO state. Here, based on a model constructed on the basis of available experiments, we show that an FFLO state competes with an SDW phase. The SDW state in CeCoIn_{5} is stabilized when the field is directed close to the a-b plane. When the field is rotated toward the c axis, the FFLO state emerges, and the SDW phase disappears. In the FFLO state, the nodal planes with extra quasiparticles (where the superconducting order parameter is zero) are perpendicular to the field, and in the SDW phase, the quasiparticle density of states is reduced. We test this model prediction by measuring heat transported by normal quasiparticles in the superconducting state. As a function of field, we observe a reduction of thermal conductivity for field close to the a-b plane and an enhancement of thermal conductivity when field is close to the c axis, consistent with theoretical expectations. Our modeling and experiments, therefore, indicate the existence of the FFLO state when field is parallel to the c axis.
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Affiliation(s)
- Shi-Zeng Lin
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Duk Y Kim
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 16419, Republic of Korea
| | - Eric D Bauer
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Filip Ronning
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J D Thompson
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Roman Movshovich
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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10
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Wang Z, Su Y, Lin SZ, Batista CD. Skyrmion Crystal from RKKY Interaction Mediated by 2D Electron Gas. Phys Rev Lett 2020; 124:207201. [PMID: 32501075 DOI: 10.1103/physrevlett.124.207201] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/13/2020] [Accepted: 05/05/2020] [Indexed: 06/11/2023]
Abstract
We consider a C_{6} invariant lattice of magnetic moments coupled via a Kondo exchange J with a 2D electron gas (2DEG). The effective Ruderman-Kittel-Kasuya-Yosida interaction between the moments stabilizes a magnetic skyrmion crystal in the presence of magnetic field and easy-axis anisotropy. An attractive aspect of this mechanism is that the magnitude of the magnetic ordering wave vectors, Q_{ν} (ν=1, 2, 3), is dictated by the Fermi wave number k_{F}: |Q_{ν}|=2k_{F}. Consequently, the topological contribution to the Hall conductivity of the 2DEG becomes of the order of the quantized value, e^{2}/h, when J is comparable to the Fermi energy ε_{F}.
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Affiliation(s)
- Zhentao Wang
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Ying Su
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Shi-Zeng Lin
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Cristian D Batista
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA
- Quantum Condensed Matter Division and Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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11
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Lin SZ, Dong HJ, Sun JP. [Expanding test and normalization for HIV/AIDS prevention and control]. Zhonghua Yu Fang Yi Xue Za Zhi 2017; 50:929-931. [PMID: 27903351 DOI: 10.3760/cma.j.issn.0253-9624.2016.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Expanding real-name HIV test is the basis of the real-time reporting system in China, and it plays an important role for the progress. In year of 2003, there were 45 092 cases of HIV positives reported cumulatively, which accounted for only 5.4% of the estimated population of HIV positives. Since implementation of real-name HIV test and establishment, real-time reporting system, up to year 2005, the total of reported HIV positives was 577 000, which took up 67.9% of the estimated HIV positives. Also among reported cases, 387 000 cases have received the anti-retroviral treatment. Normalization of HIV prevention and control will pave the way to medical insurance for HIV positives. It is a goal that all the people have medical insurance in China, and the normalization is an ideal working condition, and real-name HIV test is a measure for it. The both are very closely connected and improving each anther.
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Affiliation(s)
- S Z Lin
- School of Public Health, Zhejiang University, Hangzhou 310058, China
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12
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Kim DY, Lin SZ, Weickert F, Bauer ED, Ronning F, Thompson JD, Movshovich R. Resonances in the Field-Angle-Resolved Thermal Conductivity of CeCoIn_{5}. Phys Rev Lett 2017; 118:197001. [PMID: 28548529 DOI: 10.1103/physrevlett.118.197001] [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] [Received: 12/04/2016] [Indexed: 06/07/2023]
Abstract
The thermal conductivity measurement in a rotating magnetic field is a powerful probe of the structure of the superconducting energy gap. We present high-precision measurements of the low-temperature thermal conductivity in the unconventional heavy-fermion superconductor CeCoIn_{5}, with the heat current J along the nodal [110] direction of its d_{x^{2}-y^{2}} order parameter and the magnetic field up to 7 T rotating in the ab plane. In contrast to the smooth oscillations found previously for J∥[100], we observe a sharp resonancelike peak in the thermal conductivity when the magnetic field is also in the [110] direction, parallel to the heat current. We explain this peak qualitatively via a model of the heat transport in a d-wave superconductor. In addition, we observe two smaller but also very sharp peaks in the thermal conductivity for the field directions at angles Θ≈±33° with respect to J. The origin of the observed resonances at Θ≈±33° at present defies theoretical explanation. The challenge of uncovering their source will dictate exploring theoretically more complex models, which might include, e.g., fine details of the Fermi surface, Andreev bound vortex core states, a secondary superconducting order parameter, and the existence of gaps in spin and charge excitations.
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Affiliation(s)
- Duk Y Kim
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Shi-Zeng Lin
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | | | - Eric D Bauer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Filip Ronning
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Roman Movshovich
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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13
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Kim H, Lin SZ, Graf MJ, Miyata Y, Nagai Y, Kato T, Hasegawa Y. Electrical Conductivity through a Single Atomic Step Measured with the Proximity-Induced Superconducting Pair Correlation. Phys Rev Lett 2016; 117:116802. [PMID: 27661710 DOI: 10.1103/physrevlett.117.116802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Indexed: 06/06/2023]
Abstract
Local disordered nanostructures in an atomically thick metallic layer on a semiconducting substrate play significant and decisive roles in transport properties of two-dimensional (2D) conductive systems. We measured the electrical conductivity through a step of monoatomic height in a truly microscopic manner by using as a signal the superconducting pair correlation induced by the proximity effect. The transport property across a step of a one-monolayer Pb surface metallic phase, formed on a Si(111) substrate, was evaluated by inducing the pair correlation around the local defect and measuring its response, i.e., the reduced density of states at the Fermi energy using scanning tunneling microscopy. We found that the step resistance has a significant contribution to the total resistance on a nominally flat surface. Our study also revealed that steps in the 2D metallic layer terminate the propagation of the pair correlation. Superconductivity is enhanced between the first surface step and the superconductor-normal-metal interface by reflectionless tunneling when the step is located within a coherence length.
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Affiliation(s)
- Howon Kim
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5, Kashiwa-no-ha, Kashiwa 277-8581 Japan
| | - Shi-Zeng Lin
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Matthias J Graf
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Yoshinori Miyata
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5, Kashiwa-no-ha, Kashiwa 277-8581 Japan
| | - Yuki Nagai
- CCSE, Japan Atomic Energy Agency, Kashiwa, Chiba 277-8587, Japan
| | - Takeo Kato
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5, Kashiwa-no-ha, Kashiwa 277-8581 Japan
| | - Yukio Hasegawa
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5, Kashiwa-no-ha, Kashiwa 277-8581 Japan
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14
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Abstract
The term frustration refers to lattice systems whose ground state cannot simultaneously satisfy all the interactions. Frustration is an important property of correlated electron systems, which stems from the sign of loop products (similar to Wilson products) of interactions on a lattice. It was early recognized that geometric frustration can produce rather exotic physical behaviors, such as macroscopic ground state degeneracy and helimagnetism. The interest in frustrated systems was renewed two decades later in the context of spin glasses and the emergence of magnetic superstructures. In particular, Phil Anderson's proposal of a quantum spin liquid ground state for a two-dimensional lattice S = 1/2 Heisenberg magnet generated a very active line of research that still continues. As a result of these early discoveries and conjectures, the study of frustrated models and materials exploded over the last two decades. Besides the large efforts triggered by the search of quantum spin liquids, it was also recognized that frustration plays a crucial role in a vast spectrum of physical phenomena arising from correlated electron materials. Here we review some of these phenomena with particular emphasis on the stabilization of chiral liquids and non-coplanar magnetic orderings. In particular, we focus on the ubiquitous interplay between magnetic and charge degrees of freedom in frustrated correlated electron systems and on the role of anisotropy. We demonstrate that these basic ingredients lead to exotic phenomena, such as, charge effects in Mott insulators, the stabilization of single magnetic vortices, as well as vortex and skyrmion crystals, and the emergence of different types of chiral liquids. In particular, these orderings appear more naturally in itinerant magnets with the potential of inducing a very large anomalous Hall effect.
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Affiliation(s)
- Cristian D Batista
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN 37996, USA. Theory Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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15
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Abstract
We study the effect of a nonmagnetic impurity inserted in a two-dimensional frustrated ferromagnet above its saturation magnetic field H_{sat} for arbitrary spin S. We demonstrate that the ground state includes a magnetic vortex that is nucleated around the impurity over a finite range of magnetic field H_{sat}≤H≤H_{sat}^{I}. Upon approaching the quantum critical point at H=H_{sat}, the radius of the magnetic vortex diverges as the magnetic correlation length: ξ∝1/sqrt[H-H_{sat}]. These results are derived both for the lattice and in the continuum limit.
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Affiliation(s)
- Shi-Zeng Lin
- Theoretical Division and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Satoru Hayami
- Theoretical Division and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Department of Physics, Hokkaido University, Sapporo 060-0810, Japan
| | - Cristian D Batista
- Theoretical Division and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA
- Quantum Condensed Matter Division and Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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16
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Lin SZ. Ground state, collective mode, phase soliton and vortex in multiband superconductors. J Phys Condens Matter 2014; 26:493202. [PMID: 25398159 DOI: 10.1088/0953-8984/26/49/493202] [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: 06/04/2023]
Abstract
This article reviews theoretical and experimental work on the novel physics in multiband superconductors. Multiband superconductors are characterized by multiple superconducting energy gaps in different bands with interaction between Cooper pairs in these bands. The discovery of prominent multiband superconductors MgB2 and later iron-based superconductors, has triggered enormous interest in multiband superconductors. The most recently discovered superconductors exhibit multiband features. The multiband superconductors possess novel properties that are not shared with their single-band counterpart. Examples include: the time-reversal symmetry broken state in multiband superconductors with frustrated interband couplings; the collective oscillation of number of Cooper pairs between different bands, known as the Leggett mode; and the phase soliton and fractional vortex, which are the main focus of this review. This review presents a survey of a wide range of theoretical exploratory and experimental investigations of novel physics in multiband superconductors. A vast amount of information derived from these studies is shown to highlight unusual and unique properties of multiband superconductors and to reveal the challenges and opportunities in the research on the multiband superconductivity.
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Affiliation(s)
- Shi-Zeng Lin
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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17
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Dela Peña I, Sanberg PR, Acosta S, Tajiri N, Lin SZ, Borlongan CV. Stem cells and G-CSF for treating neuroinflammation in traumatic brain injury: aging as a comorbidity factor. J Neurosurg Sci 2014; 58:145-149. [PMID: 24844175 PMCID: PMC4117389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Traumatic brain injury (TBI), often called the signature wound of Iraq and Afghanistan wars, is characterized by a progressive histopathology and long-lasting behavioral deficits. Treatment options for TBI are limited and patients are usually relegated to rehabilitation therapy and a handful of experimental treatments. Stem cell-based therapies offer alternative treatment regimens for TBI, and have been intended to target the delayed therapeutic window post-TBI, in order to promote "neuroregeneration," in lieu of "neuroprotection" which can be accomplished during acute TBI phase. However, these interventions may require adjunctive pharmacological treatments especially when aging is considered as a comorbidity factor for post-TBI health outcomes. Here, we put forward the concept that a combination therapy of human umbilical cord blood cell (hUCB) and granulocyte-colony stimulating factor (G-CSF) attenuates neuroinflammation in TBI, in view of the safety and efficacy profiles of hUCB and G-CSF, their respective mechanisms of action, and efficacy of hUCB+G-CSF combination therapy in TBI animal models. Further investigations on the neuroinflammatory pathway as a key pathological hallmark in acute and chronic TBI and also as a major therapeutic target of hUCB+G-CSF are warranted in order to optimize the translation of this combination therapy in the clinic.
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Affiliation(s)
- I Dela Peña
- Center of Excellence for Aging and Brain Repair Department of Neurosurgery and Brain Repair University of South Florida Morsani College of Medicine Tampa, FL, USA -
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18
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Lin SZ, Batista CD, Reichhardt C, Saxena A. ac current generation in chiral magnetic insulators and Skyrmion motion induced by the spin Seebeck effect. Phys Rev Lett 2014; 112:187203. [PMID: 24856718 DOI: 10.1103/physrevlett.112.187203] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Indexed: 06/03/2023]
Abstract
We show that a temperature gradient induces an ac electric current in multiferroic insulators when the sample is embedded in a circuit. We also show that a thermal gradient can be used to move magnetic Skyrmions in insulating chiral magnets: the induced magnon flow from the hot to the cold region drives the Skyrmions in the opposite direction via a magnonic spin transfer torque. Both results are combined to compute the effect of Skyrmion motion on the ac current generation and demonstrate that Skyrmions in insulators are a promising route for spin caloritronics applications.
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Affiliation(s)
- Shi-Zeng Lin
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Cristian D Batista
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Charles Reichhardt
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Avadh Saxena
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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19
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Lin SZ, Kamiya Y, Chern GW, Batista CD. Stiffness from disorder in triangular-lattice Ising thin films. Phys Rev Lett 2014; 112:155702. [PMID: 24785055 DOI: 10.1103/physrevlett.112.155702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Indexed: 06/03/2023]
Abstract
We study the triangular lattice Ising model with a finite number of vertically stacked layers and demonstrate a low temperature reentrance of two Berezinskii-Kosterlitz-Thouless transitions, which results in an extended disordered regime down to T=0. Numerical results are complemented with the derivation of an effective low-temperature dimer theory. Contrary to order by disorder, we present a new scenario for fluctuation-induced ordering in frustrated spin systems. While short-range spin-spin correlations are enhanced by fluctuations, quasi-long-range ordering is precluded at low enough temperatures by proliferation of topological defects.
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Affiliation(s)
- Shi-Zeng Lin
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Yoshitomo Kamiya
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA and iTHES Research Group and Condensed Matter Theory Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Gia-Wei Chern
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Cristian D Batista
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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20
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Lin SZ, Bulaevskii LN. I-V characteristics of short superconducting nanowires with different bias and shunt: a dynamic approach. J Phys Condens Matter 2014; 26:155703. [PMID: 24674877 DOI: 10.1088/0953-8984/26/15/155703] [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] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We derived the I-V characteristics of short nanowire in a circuit with and without resistive and inductive shunt. For this we used numerical calculations in the framework of time-dependent Ginzburg-Landau equations with different relaxation times for the amplitude and phase dynamics. We also derived the dependence of the I-V characteristics on flux in a superconducting quantum interference device made of two such weak links.
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Affiliation(s)
- Shi-Zeng Lin
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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21
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Abstract
We derive the effective heat current density operator for the strong-coupling regime of Mott insulators. Similarly to the case of the electric current density, the leading contribution to this effective operator is proportional to the local scalar spin chirality χ(jkl)=S(l)·(S(j)×S(k)). This common form of the effective heat and electric current density operators leads to a novel cross response in Mott insulators. A heat current induces a distribution of orbital magnetic moments in systems containing loops of an odd number of hopping terms. The relative orientation of the orbital moments depends on the particular lattice of magnetic ions. This subtle effect arises from the symmetries that the heat and electric currents have in common.
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Affiliation(s)
- Shi-Zeng Lin
- Theoretical Division, T4, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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22
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Abstract
Recently, transport measurements have been carried out in resistively shunted long superconducting nanowires (Brenner et al 2012 Phys. Rev. B 85 224507). The measured voltage-current (V-I) characteristics were explained by the appearance of the phase slip centers in the shunted wire, and the whole wire was modeled as a single Josephson junction. The kinetic inductance of the long nanowires used in experiments is generally large. Here we argue that the shunted superconducting nanowire acts as a Josephson junction in series with an inductor. The inductance depends on the length and the cross section of the wire. The inclusion of inductance in our analysis modifies the V-I curves, and increases the rate of switching from the superconducting state to the resistive state. The quantitative differences can be quite large in some practical parameter sets, and might be important to properly understand the experimental results. Our proposed model can be verified experimentally by studying the shunted superconducting nanowires of different lengths and cross sections.
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Affiliation(s)
- Shi-Zeng Lin
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
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23
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Lin SZ, Reichhardt C, Batista CD, Saxena A. Driven Skyrmions and dynamical transitions in chiral magnets. Phys Rev Lett 2013; 110:207202. [PMID: 25167443 DOI: 10.1103/physrevlett.110.207202] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 03/21/2013] [Indexed: 06/03/2023]
Abstract
We study the dynamics of Skyrmions in chiral magnets in the presence of a spin polarized current. The motion of Skyrmions in the ferromagnetic background excites spin waves and contributes to additional damping. At a large current, the spin wave spectrum becomes gapless and Skyrmions are created dynamically from the ferromagnetic state. At an even higher current, these Skyrmions are strongly deformed due to the damping and become unstable at a threshold current, leading to a chiral liquid. We show how Skyrmions can be created by increasing the current in the magnetic spiral state. We then construct a dynamic phase diagram for a chiral magnet with a current. The instability transitions between different states can be observed as experimentally clear signatures in the transport measurements, such as jumps and hysteresis.
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Affiliation(s)
- Shi-Zeng Lin
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Charles Reichhardt
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Cristian D Batista
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Avadh Saxena
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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24
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Lin SZ, Bulaevskii LN. Dissociation transition of a composite lattice of magnetic vortices in the flux-flow regime of two-band superconductors. Phys Rev Lett 2013; 110:087003. [PMID: 23473190 DOI: 10.1103/physrevlett.110.087003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Indexed: 06/01/2023]
Abstract
In multiband superconductors, each superconducting condensate supports vortices with fractional quantum flux. In the ground state, vortices in different bands are spatially bounded together to form a composite vortex, carrying one quantum flux Φ(0). Here we predict dissociation of the composite vortices lattice in the flux flow state due to the disparity of the vortex viscosity and flux of the vortex in different bands. For a small driving current, composite vortices start to deform, but the constituting vortices in different bands move with the same velocity. For a large current, composite vortices dissociate and vortices in different bands move with different velocities. The dissociation transition shows up as an increase of flux flow resistivity. In the dissociated phase, Shapiro steps are developed when an ac current is superimposed with a dc current.
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Affiliation(s)
- Shi-Zeng Lin
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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25
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Bulaevskii LN, Lin SZ. Prediction of polaronlike vortices and a dissociation depinning transition in magnetic superconductors: the example of ErNi2B2C. Phys Rev Lett 2012; 109:027001. [PMID: 23030195 DOI: 10.1103/physrevlett.109.027001] [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: 05/02/2012] [Indexed: 06/01/2023]
Abstract
In borocarbide ErNi2B2C, the phase transition to the commensurate spin density wave at 2.3 K leaves 1/20 part of Ising-like Er spins practically free. Vortices polarize these spins nonuniformly and repolarize them when moving. At a low spin relaxation rate and at low bias currents, vortices carrying magnetic polarization clouds become polaronlike and their velocities are determined by the effective drag coefficient, which is significantly bigger than the Bardeen-Stephen (BS) one. As current increases, at a critical current J(c) vortices release polarization clouds and the velocity as well as the voltage in the I-V characteristics jump to values corresponding to the BS drag coefficient. The nonuniform components of the magnetic field and magnetization drop as velocity increases, resulting in weaker polarization and discontinuous dynamic dissociation depinning transition. As current decreases, on the way back, vortices are retrapped by polarization clouds at the current J(r)<J(c).
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Affiliation(s)
- Lev N Bulaevskii
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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26
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Lin SZ, Hu X. Massless Leggett mode in three-band superconductors with time-reversal-symmetry breaking. Phys Rev Lett 2012; 108:177005. [PMID: 22680897 DOI: 10.1103/physrevlett.108.177005] [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] [Received: 07/05/2011] [Revised: 01/04/2012] [Indexed: 06/01/2023]
Abstract
The Leggett mode associated with out-of-phase oscillations of the superconducting phase in multiband superconductors usually is heavy due to interband coupling, which makes its excitation and detection difficult. We report on the existence of a massless Leggett mode in three-band superconductors with time-reversal-symmetry breaking. The mass of this Leggett mode is small close to the time-reversal-symmetry-breaking transition and vanishes at the transition point, and thus locates within the smallest superconducting energy gap, which makes it stable and detectable, e.g., by means of the Raman spectroscopy. The thermodynamic consequences of this massless mode and possible realization in iron-based superconductors are also discussed.
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Affiliation(s)
- Shi-Zeng Lin
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, Tsukuba 305-0044, Japan
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27
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Lin SZ, Hu X. Radiation of terahertz electromagnetic waves from build-in nano Josephson junctions of cuprate high-T(c) superconductors. J Nanosci Nanotechnol 2011; 11:2916-2921. [PMID: 21776653 DOI: 10.1166/jnn.2011.3907] [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] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The nano-scale intrinsic Josephson junctions in highly anisotropic cuprate superconductors have potential for generation of terahertz electromagnetic waves. When the thickness of a superconductor sample is much smaller than the wavelength of electromagnetic waves in vacuum, the superconductor renders itself as a cavity. Unlike conventional lasers, the presence of the cavity does not guarantee a coherent emission because of the internal degree of freedom of the superconductivity phase in long junctions. We study the excitation of terahertz wave by solitons in a stack of intrinsic Josephson junctions, especially for relatively short junctions. Coherent emission requires a rectangular configuration of solitons. However such a configuration is unstable against weak fluctuations, contrarily solitons favor a triangular lattice corresponding to an out-phase oscillation of electromagnetic waves. To utilize the cavity, we propose to use an array of stacks of short intrinsic Josephson junctions to generate powerful terahertz electromagnetic waves. The cavity synchronizes the plasma oscillation in different stacks and the emission intensity is predicted to be proportional to the number of stacks squared.
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Affiliation(s)
- Shi-Zeng Lin
- WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-0044, Japan
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28
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Lin SZ, Zheng B. Short-time critical dynamics at perfect and imperfect surfaces. Phys Rev E Stat Nonlin Soft Matter Phys 2008; 78:011127. [PMID: 18763939 DOI: 10.1103/physreve.78.011127] [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] [Received: 05/20/2008] [Indexed: 05/26/2023]
Abstract
With Monte Carlo simulations, we study the dynamic relaxation at perfect and imperfect surfaces of the three-dimensional Ising model with an ordered initial state. The time evolution of the surface magnetization, the line magnetization of the defect line, and the corresponding susceptibilities and second cumulants is carefully examined. Universal dynamic scaling forms including a dynamic crossover scaling form are identified at the ordinary, special, and surface phase transitions. The critical exponents beta1 of the surface magnetization and beta2 of the line magnetization are extracted. The impact of the defect line on the universality classes is investigated.
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Affiliation(s)
- S Z Lin
- Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou, China
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Yang KL, Chu CC, Huang CH, Lin SZ, Hsu WL, Liu DW, Lin PY. Discovery of HLA-DRB1*0331 in a Taiwanese marrow donor and the importance of sequence-based typing in a rare or previously unrecognized allele. Int J Immunogenet 2007; 34:91-5. [PMID: 17373933 DOI: 10.1111/j.1744-313x.2007.00662.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [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: 11/26/2022]
Abstract
We describe here a novel HLA-DRB1* allele, DRB1*0331, observed from a Taiwanese bone marrow donor using DNA sequence-based typing (SBT) method. The 'new' allele differs from DRB1*0306 and DRB1*0325 by one nucleotide at positions 196 and 227, respectively. Nucleotide mutations caused amino acid substitutions from N to Y at codon 37 and from F to Y at codon 47, as compared with amino acid sequence encoded by the DRB1*030101 allele. The donor was first typed as DRB1*0403/0406/0439/0441/0446/0451/0452 (NMDP code DRB1*04XX) and DRB1*0304/0323/0325 (NMDP code DRB1*03APDA) by sequence-specific oligonucleotide (SSO) typing kit. Subsequent typing of the donor by high-resolution sequence-specific primer (SSP) protocol indicated DRB1*0403 and DRB1*0306. The anomalous result of DRB1*03 was resolved by SBT and recognized as DRB1*0331. We concluded that SSP or SSO alone may mistype a precedent unrecognized allele and that two different typing techniques or SBT may have to be employed to safe guard true HLA typing when rare alleles are encountered at the first time.
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Affiliation(s)
- K L Yang
- Laboratory of Immunogenetics, Tzu-Chi Stem Cells Centre, Buddhist Tzu-Chi Marrow Donor Registry, Hualien, Taiwan.
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Lin SZ, Zheng B, Trimper S. Computer simulations of two-dimensional melting with dipole-dipole interactions. Phys Rev E Stat Nonlin Soft Matter Phys 2006; 73:066106. [PMID: 16906913 DOI: 10.1103/physreve.73.066106] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Revised: 03/20/2006] [Indexed: 05/11/2023]
Abstract
We perform molecular dynamics and Monte Carlo simulations of two-dimensional melting with dipole-dipole interactions. Both static and dynamic behaviors are examined. In the isotropic liquid phase, the bond orientational correlation length xi 6 and susceptibility chi 6 are measured, and the data are fitted to the theoretical ansatz. An algebraic decay is detected for both spatial and temporal bond orientational correlation functions in an intermediate temperature regime, and it provides an explicit evidence for the existence of the hexatic phase. From the finite-size scaling analysis of the global bond orientational order parameter, the disclination unbinding temperature Ti is estimated. In addition, from dynamic Monte Carlo simulations of the positional order parameter, we extract the critical exponents at the dislocation unbinding temperature Tm. All the results are in agreement with those from experiments and support the Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) theory.
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Affiliation(s)
- S Z Lin
- Zhejiang University, Zhejiang Institute of Modern Physics, Hangzhou 310027, People's Republic of China
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Abstract
Stem cell therapies are an important strategy for the treatment of stroke. Bone marrow-derived stem cells (BMSCs) may promote structural and functional repair in several organs via stem cell plasticity. The tissue damage could stimulate the stem cells migration, and they track into the site of damage and then undergo differentiation. The plasticity functions of BMSCs in an injuries tissue are dependent on the specific signals present in the local environment of the damaged tissue. Recent studies have also identified the specific molecular signals, such as SDF-1/CXCR4, required for the interaction of BMSCs and damaged host tissues. This review summarizes the current understanding of how BMSCs reach and function in cerebral ischemic tissues.
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Affiliation(s)
- D D Liu
- Department of Dentistry, Tzu-Chi Buddhist General Hospital, Tzu-Chi University, Hualien, Taiwan
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Lin JJ, Chen CH, Yueh KC, Chang CY, Lin SZ. A CD14 monocyte receptor polymorphism and genetic susceptibility to Parkinson's disease for females. Parkinsonism Relat Disord 2006; 12:9-13. [PMID: 16337421 DOI: 10.1016/j.parkreldis.2005.07.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Revised: 07/11/2005] [Accepted: 07/13/2005] [Indexed: 11/21/2022]
Abstract
Recent studies suggest that inflammation may play an important role in the pathogenesis of Parkinson's disease (PD). Because the C(-260) --> T polymorphism in the promoter of the CD14 monocyte receptor gene (pCD14) could affect the predisposition to the inflammatory response, we conducted a case-control study to investigate a possible genetic susceptibility of the pCD14 polymorphism in patients with PD. This study included 200 sporadic PD patients and 200 controls, matched by sex and case-control pairs for age at onset in the case. All observed genotype frequencies were in Hardy-Weinberg equilibrium. Results revealed that the CD14-T allele of the pCD14 polymorphism in the female PD patients existed statistically significant difference from that of the female controls (OR = 1.262, P = 0.038), but not for male. Female individuals with homozygote CD14-TT genotype were significantly increased risk of PD by 1.28 time (P = 0.027). Furthermore, a logistic regression analysis confirmed that the homozygote CD14-TT genotype was an independent risk factor for PD (OR = 1.576, P = 0.030). In conclusion, results of this study indicate the pCD14 polymorphism to be a genetic risk factor for PD in females.
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Affiliation(s)
- J J Lin
- Department of Neurology, Chushang Show-Chwan Hospital, Nantou, 557, Taiwan, ROC.
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Lin JJ, Yueh KC, Chang CY, Chen CH, Lin SZ. The homozygote AA genotype of the α1-antichymotrypsin gene may confer protection against early-onset Parkinson's disease in women. Parkinsonism Relat Disord 2004; 10:469-73. [PMID: 15542006 DOI: 10.1016/j.parkreldis.2004.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There has been increasing evidence suggesting that inflammatory response maybe involved in the pathogenesis of Parkinson's disease (PD). Alpha1-antichymotrypsin gene (ACT) has been regarded as a susceptibility factor for PD in the past, but the evidence remains controversial. This case-control study was designed to investigate the association of alpha1-antichymotrypsin gene (ACT) polymorphism between 210 Taiwanese patients with clinical definite sporadic PD and 260 controls, matched by age and sex. There were no differences of allelic frequency (A and T) and genotype polymorphism (AA, AT and TT) of the ACT in PD patients from the controls. However, there were significantly fewer early-onset PD (onset age younger than 60 years) or PD women carrying the homozygote AA genotype (ACT-AA) than in controls (p=0.046 and 0.044, respectively). Further analysis revealed that the reduced risk of ACT-AA was particularly significant among PD women with the onset age younger than 60 years (OR=0.796, 95% CI=0.749-0.847, p<0.0001). This study shows that ACT-AA may confer a modest protection against developing early-onset PD in women.
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Affiliation(s)
- J J Lin
- Department of Neurology, Chushang Show-Chwan Hospital, 75 Sec. 2 Chi-Shang Road, Chushang Jenn, Nantou 557, Taiwan.
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Lee CC, Lin SZ, Wang Y, Lin JJ, Liu JY, Chen GJ, Chiang YH, Liu JC, Zhou FC. First human ventral mesencephalon and striatum cografting in a Parkinson patient. Acta Neurochir Suppl 2003; 87:159-62. [PMID: 14518545 DOI: 10.1007/978-3-7091-6081-7_33] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Fetal ventral mesencephalon (VM) transplantation has been reported to improve parkinsonian symptoms. Animal studies show that cografting of striatal tissue increases the survival of dopamine neurons. Whether or not VM and striatum cografting could ameliorate motor dysfunction in a Parkinson's disease (PD) patient was explored in this study. The patient was a 53-year-old male who had presented with symptoms of tremor, rigidity and bradykinesia for 11 years. He had been treated with L-dopa and had progressive deterioration of symptoms even with the daily dosage of L-dopa increased to 900 mg per day. Before transplantation, his PD symptoms were scored with Unified Parkinson's Disease Rating Scale (UPDRS) and video recordings. The influx constant (ki) of the [18F] 6-fluoro-L-dopa uptake in the striatum was measured by positron emission tomography (PET) imaging. The fetal VM and the lateral part of the lateral ganglionic eminence (LGE) were cografted into the right putamen and, one week later, fetal VM alone was transplanted into the left putamen. After the transplantation, the patient's UPDRS score improved from 128 to 62 at 6 months and to 24 at 22 months during the "off" phase. The score of daily living disability improved from 35 to 18 at 6 months and to 10 at 22 months post transplantation. Twenty-two months after grafting, "off" phases were almost absent, and the freezing had totally disappeared. The [18F] 6-fluoro-L-dopa PET studies were performed 1 month before and 21 months after transplantation. The ki for [18F] 6-fluoro-L-dopa was decreased by 15% in the right caudate and 5% in the left caudate, both of which did not have any ventral mesencephalic grafts. However, the ki was increased by 35%, in the left non-cografted putamen, and by 58% in the right cografted putamen. In conclusion, cografting the fetal VM and the LGE in the putamen may improve the motor function of PD patients.
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Affiliation(s)
- C C Lee
- Department of Radiology, Neuro-Medical Scientific Center, Tzu-Chi General Hospital, Tzu-Chi University, Hualien, Taiwan
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Lee-Chen GJ, Lin SP, Lin SZ, Chuang CK, Hsiao KT, Huang CF, Lien WC. Identification and characterisation of mutations underlying Sanfilippo syndrome type B (mucopolysaccharidosis type IIIB). J Med Genet 2002; 39:E3. [PMID: 11836372 PMCID: PMC1735050 DOI: 10.1136/jmg.39.2.e3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- G J Lee-Chen
- Department of Biology, National Taiwan Normal University, Taipei, Taiwan, ROC
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Huang WS, Lin SZ, Lin JC, Wey SP, Ting G, Liu RS. Evaluation of early-stage Parkinson's disease with 99mTc-TRODAT-1 imaging. J Nucl Med 2001; 42:1303-8. [PMID: 11535717] [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: 02/21/2023] Open
Abstract
UNLABELLED Parkinson's disease is a progressive neurodegenerative disorder characterized by a selective loss of dopamine in the striatum. Problems remain in the accurate diagnosis of Parkinson's disease. A 99mTc-labeled tropane derivative that binds to dopamine transporter with high selectivity is [2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3,2,1]oct-2-yl]methyl](2-mercaptoethyl)amino]ethyl]amino]ethanethiolato(3-)-N2,N2',S2,S2']oxo-[1R-(exo-exo)] (TRODAT-1). The purpose of this study was to investigate the potential usefulness of 99mTc-TRODAT-1 imaging in the evaluation of patients with early-stage Parkinson's disease. METHODS Thirty-four patients with early-stage idiopathic Parkinson's disease were recruited. For all patients, the Parkinson's disease was stage 2 or less as assessed by the Hoehn and Yahr scale. Seventeen age-matched healthy volunteers (8 men, 9 women) served as controls. 99mTc-TRODAT-1 was prepared from a lyophilized kit. Brain SPECT imaging was performed between 165 and 195 min after injection, using a double-head camera equipped with fanbeam collimators. Specific uptake in the striatum and its subregions, including the putamen and caudate nucleus, was calculated and compared with that of the other sides and of healthy volunteers. RESULTS A continuous reduction in specific striatal uptake of 99mTc-TRODAT-1 with increasing disease severity was found in Parkinson's disease patients (control vs. stage I vs. stage II, 1.98 vs. 1.62 vs. 1.22, respectively, P < 0.01). The changes were magnified by measurement of specific putaminal uptake (control vs. stage I vs. stage II, 1.81 vs. 1.27 vs. 0.94, respectively, P < 0.01). The mean values of specific putaminal uptake contralateral to the more affected limbs were significantly decreased compared with the ipsilateral sides in both stage I and stage II groups (1.02 vs. 1.49 for stage I and 0.73 vs. 1.14 for stage II, P < 0.01). Moreover, a significant loss of putaminal uptake ipsilateral to the symptoms was found in the stage I group compared with the healthy volunteers (1.49 vs. 1.81, P < 0.01). The difference became greater when the posterior putaminal uptakes were compared. No remarkable adverse reactions were found in either healthy volunteers or Parkinson's disease patients during or after imaging. CONCLUSION For clinical practice, 99mTc-TRODAT-1 may serve as a useful imaging agent for the early detection of Parkinson's disease.
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Affiliation(s)
- W S Huang
- Department of Nuclear Medicine, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan
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Wang Y, Chang CF, Morales M, Chou J, Chen HL, Chiang YH, Lin SZ, Cadet JL, Deng X, Wang JY, Chen SY, Kaplan PL, Hoffer BJ. Bone morphogenetic protein-6 reduces ischemia-induced brain damage in rats. Stroke 2001; 32:2170-8. [PMID: 11546913 DOI: 10.1161/hs0901.095650] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Bone morphogenetic protein-6 (BMP6) and its receptors are expressed in adult and fetal brain. Receptors for BMP6 are upregulated in adult brain after injury, leading to the suggestion that BMP6 is involved in the physiological response to neuronal injury. The purpose of this study was to determine whether there was a neuroprotective effect of BMP6 in vivo and in vitro. METHODS Lactate dehydrogenase and microtubule-associated protein-2 (MAP-2) activities were used to determine the protective effect of BMP6 against H(2)O(2) in primary cortical cultures. The neuroprotective effects of BMP6 were also studied in chloral hydrate-anesthetized rats. BMP6 or vehicle was injected into right cerebral cortex before transient right middle cerebral artery (MCA) ligation. Animals were killed for triphenyl-tetrazolium chloride staining, caspase-3 immunoreactivity and enzymatic assays, and TUNEL assay. A subgroup of animals were used for locomotor behavioral assays. RESULTS Application of H(2)O(2) increased lactate dehydrogenase activity and decreased the density of MAP-2(+) neurons in culture. Both responses were attenuated by BMP6 pretreatment. Complementary in vivo studies showed that pretreatment with BMP6 increased motor performance and generated less cerebral infarction induced by MCA ligation/reperfusion in rats. Pretreatment with BMP6 did not alter cerebral blood flow or physiological parameters. There was decreased ischemia-induced caspase-3 immunoreactivity, caspase-3 enzymatic activity, and density of TUNEL-positive cells in ischemic cortex in BMP6-treated animals. CONCLUSIONS BMP6 reduces ischemia/reperfusion injury, perhaps by attenuating molecular events underlying apoptosis.
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Affiliation(s)
- Y Wang
- National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD, USA.
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Lin JJ, Lin SZ, Lin GY, Chang DC, Lee CC. Treatment of intractable generalized dystonia by bilateral posteroventral pallidotomy--one-year results. Zhonghua Yi Xue Za Zhi (Taipei) 2001; 64:231-8. [PMID: 11458761] [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: 02/20/2023]
Abstract
BACKGROUND Recent study has revealed that bilateral posteroventral pallidotomy (PVP) significantly improve dystonic movements and improve motor function of those patients with generalized dystonia (GD). However, there is only a limited number of patients who have been reported so far. METHODS This study was conducted to evaluate the clinical efficacy of surgical treatment with bilateral PVP on patients with intractable GD. All the studied patients were regularly rated with standardized scales (Burke-Fahn-Marsden Evaluation Scale for Dystonia) for dystonic movement and living disability before and after surgery. RESULTS There were 18 patients, 8 males and 10 females with an average age of 24.8 years, included in the study. Postoperatively, there were slow, partial, but steady improvements of the dystonic movement and daily living function. Maximal effects were noted at the sixth month and the clinical benefits were sustained one year after the surgical treatment when there were statistically significant improvements in 13% of total dystonia movement score and 9% of the total disability score (p < 0.05). Upon further analysis, improvements of dystonic movements were statistically significant in the regions of mouth (50%), speech/swallowing (19%) and neck (43%), and daily living functions in speech (14%) and eating/swallowing (29%). CONCLUSIONS Bilateral posteroventral pallidotomy was only partially effective for the treatment of GD, and it produced clinical improvement in the dystonic movement limited to the craniocervical region. We therefore suggest that patients with GD should be carefully selected for the treatment of bilateral posteroventral pallidotomy, despite the surgery having a partially beneficial effect on this kind of movement.
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Affiliation(s)
- J J Lin
- Department of Neurology, Chushang Show-Chwan Hospital, 75, Sec. 2, Chi-Shang Road, Chushang, Nantou 557, Taiwan.
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Wang Y, Hayashi T, Chang CF, Chiang YH, Tsao LI, Su TP, Borlongan C, Lin SZ. Methamphetamine potentiates ischemia/reperfusion insults after transient middle cerebral artery ligation. Stroke 2001; 32:775-82. [PMID: 11239201 DOI: 10.1161/01.str.32.3.775] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [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: 01/08/2023]
Abstract
BACKGROUND AND PURPOSE Previous studies have indicated that both methamphetamine (MA) and ischemia/reperfusion injuries involve reactive oxygen species formation and activation of apoptotic mechanism. That MA could have a synergistic or additive effect with stroke-induced brain damage is possible. The purpose of the present study was to investigate whether administration of MA in vivo would potentiate ischemic brain injury. METHODS Adult CD-1 mice were pretreated with MA or saline. Each animal later was anesthetized with chloral hydrate and placed in a stereotaxic frame. A subset of animals received intracerebral administration of glial cell line-derived neurotrophic factor (GDNF). The right middle cerebral artery and bilateral carotids were transiently occluded for 45 minutes. Regional cerebral blood flow was measured by laser Doppler. Animals were sacrificed for triphenyltetrazolium chloride staining and p53 mRNA Northern blot assay after 24 hours of reperfusion. Cortical and striatal GDNF levels were assayed by ELISA. RESULTS We found that pretreatment with MA increased ischemia-induced cerebral infarction. Ischemia or MA alone enhanced p53 mRNA expression. Moreover, MA potentiated expression of p53 mRNA in the ischemic mouse brain. MA pretreatment decreased GDNF levels in ischemic striatum. Intracerebral administration of GDNF before ischemia reduced MA-facilitated infarction. CONCLUSIONS Our data indicate that MA exacerbates ischemic insults in brain, perhaps through the inhibition of GDNF-mediated pathways and suggest that MA may antagonize endogenous neuroprotective pathways as part of its mechanism of action.
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Affiliation(s)
- Y Wang
- National Institute on Drug Abuse, I.R.P., 5500 Nathan Shock Dr, Baltimore, MD 21224, USA.
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Tsai TH, Chen SL, Chiang YH, Lin SZ, Ma HI, Kuo SW, Tsao YP. Recombinant adeno-associated virus vector expressing glial cell line-derived neurotrophic factor reduces ischemia-induced damage. Exp Neurol 2000; 166:266-75. [PMID: 11085892 DOI: 10.1006/exnr.2000.7505] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [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: 11/22/2022]
Abstract
To explore the potential of using the recombinant adeno-associated viral (rAAV) vector, expressing glial cell line-derived neurotrophic factor (GDNF) as the gene therapy for stroke, we injected rAAV vectors expressing GDNF (rAAV-GDNF) into the cortex of rats which had been experiencing transient bilateral common carotid artery ligation and right middle cerebral artery ligation for 90 min. GDNF levels in cortical tissues of rAAV-GDNF-injected animals were significantly higher than in the control animals injected with rAAV-expressing lacZ (rAAV-lacZ), indicating that rAAV can deliver and express the GDNF gene in cortical tissues. Triphenyltetrazolium chloride tissue stain analysis revealed that the rAAV-delivered GDNF gene could rescue the brain tissues from ischemia-induced injury. Cortical tissues which received rAAV-GDNF injections had both significantly smaller total volumes of infarction and smaller areas of infarction on each brain slice than those which were injected with rAAV-lacZ. An in situ labeling analysis demonstrated significantly less apoptotic cells in cortical tissues rescued by rAAV-GDNF, indicating prevention of apoptosis as the mechanism of cortical cell protection. Moreover, immunohistochemistry staining of Neu-N indicated that the rescued brain tissues contained the same number of Neu-N-positive neuronal cells as contralateral undamaged brain tissues. This provides strong evidence that cortical neuronal cells can be rescued by GDNF gene therapy. Indeed, these findings show that the rAAV is a potential delivery vector of GDNF gene for the therapy of stroke.
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Affiliation(s)
- T H Tsai
- Department of Microbiology and Immunology, National Defense Medical Center, Taipei, Republic of China
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Zheng SQ, Li T, Xuan YX, Lin SZ, Chen LJ, Yan GM. [Neuroprotective effect of alpha-dihydroergocryptine depends on activation of nuclear factor kappa B]. Yao Xue Xue Bao 2000; 35:898-901. [PMID: 12567910] [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: 02/28/2023]
Abstract
AIM To investigate the relationship between the neuroprotective effect of alpha-dihydroergocryptine (alpha-DHEC) and the activation of nuclear factor Kappa B (NF-Kappa B). METHODS Adult male rats were subjected to cerebral ischemia induced by middle cerebral artery occlusion (MCAO). DNA binding activity of NF-Kappa B was determined with electrophoretic mobility shift assay (EMSA) in animals subjected to varying durations of cerebral ischemia. Neuroapoptosis induced by ischemic damage was measured by deoxynucleotidy transferase-mediated dUTP nick end labeling (TUNEL) assay and flow cytometry (FCM) analysis. RESULTS No change was observed in nuclear NF-Kappa B DNA binding in normal animal. A low level of constitutive NF-Kappa B DNA binding was detected in animals subjected to cerebral ischemia of 1 h, and significant increase in the amount of active NF-Kappa B in nuclear extracts was observed after cerebral ischemia of 3 h, 6 h, and 12 h. Peak of NF-Kappa B DNA binding was observed at the time point of 3 h. Animals subjected to cerebral ischemia of 3 h potentially initiates neuroapoptosis and activates NF-Kappa B in nuclear extract. Alpha-DHEC (100 micrograms.kg-1 and 150 micrograms.kg-1) showed significant protective effect on neuroapoptosis-induced by cerebral ischemia of 3 h, and inhibiting NF-Kappa B activation using 100 mg.kg-1 pyrrolidinedithiocarbamate (PDTC) in the continuous presence of alpha-DHEC, the neuroprotective effect of alpha-DHEC was blocked. CONCLUSION The findings suggest that the neuroprotetive effect of alpha-DHEC may depend on the activation of NF-Kappa B.
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Affiliation(s)
- S Q Zheng
- Department of Pharmacology, Sun Yat-Sen University of Medical Science, Guangzhou 510080, China
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42
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Yang XH, Lin SZ. [Treatment of diseased middle turbinate in endoscopic sinus surgery]. Lin Chuang Er Bi Yan Hou Ke Za Zhi 2000; 14:354-6. [PMID: 12563895] [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: 04/20/2023]
Abstract
OBJECTIVE To study the clinical significance of reservation of the middle turbinate in functional endoscopic sinus surgery (FESS) for sinusitis and/or nasal polyps. METHOD According to anatomic criteria of the middle turbinate surgery in adult, 32 cases who had sinusitis and/or nasal polyps were treated and followed up. The recovery of middle turbinate contour, postoperative ethmoid cavity and the rate of patency of the maxillary sinus ostium were observed postoperatively. RESULT 1. After 6 months, the form of middle turbinate returned to normal in 24 cases (75%), adhesions occurred in 8 cases (25%), including the closure of ethmoid sinus cavity in 2 cases. 2. The patency of maxillary sinuses ostium maintained well in 25 cases (78.1%), stenosed in 6 cases (18.8%) and closed in 1 case (3.1%). The diseased middle turbinate can recover to normal contour in most cases, often plastics in FESS. CONCLUSION Reservation of middle turbinate plays an important role in promoting the clinical cure rate.
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Affiliation(s)
- X H Yang
- First Affiliated Hospital, Guiyang Medical College, Guiyang 550004
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Lee WH, Chen A, Chao DG, Harn HJ, Lin SZ. Malignant meningioma with rhabdoid transformation. Zhonghua Yi Xue Za Zhi (Taipei) 2000; 63:492-7. [PMID: 10925541] [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: 02/17/2023]
Abstract
We report a rare case of recurrent meningioma with malignant change and rhabdoid transformation in a 54-year-old woman who presented with severe headache and progressive weakness of the right extremities. The patient had a history of atypical meningioma and had undergone a craniotomy to remove a tumor nine years earlier. We discuss the distinctive morphologic, immunohistochemical staining and ultrastructural features of a recurrent malignant meningioma. A meningioma with rhabdoid transformation may indicate aggressive biologic and clinical behavior of the tumor.
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Affiliation(s)
- W H Lee
- Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, National Defense University, Taipei, Taiwan, ROC
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Tomac AC, Grinberg A, Huang SP, Nosrat C, Wang Y, Borlongan C, Lin SZ, Chiang YH, Olson L, Westphal H, Hoffer BJ. Glial cell line-derived neurotrophic factor receptor alpha1 availability regulates glial cell line-derived neurotrophic factor signaling: evidence from mice carrying one or two mutated alleles. Neuroscience 2000; 95:1011-23. [PMID: 10682708 DOI: 10.1016/s0306-4522(99)00503-5] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [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: 01/12/2023]
Abstract
Glial cell line-derived neurotrophic factor receptor alpha1 (GFRalpha1, also known as GDNFR-alpha) is a glycolipid-anchored membrane protein of the GFRalpha family, which binds glial cell line-derived neurotrophic factor [Jing S. et al. (1996) Cell 85, 1113-1124; Treanor J. J. et al. (1996) Nature 382, 80-83], a survival factor for several populations of central and peripheral neurons, including midbrain dopamine neurons [Lin L. F. et al. (1993) Science 260, 1130-1132], and mediates its ligand-induced cell response via a tyrosine kinase receptor called Ret [Takahashi M. et al. (1988) Oncogene 3, 571-578; Takahashi M. and Cooper G. M. (1987) Molec. Cell Biol. 7, 1378-1385]. In this paper, we show that mice with a null mutation of the GFRalpha1 gene manifest epithelial-mesenchymal interaction deficits in kidney and severe disturbances of intestinal tract development similar to those seen with glial cell line-derived neurotrophic factor or Ret null mutations. There is a marked renal dysgenesis or agenesis and the intrinsic enteric nervous system fails completely to develop. We also show that newborn GFRalpha1-deficient mice display no or minimal changes in dorsal root and sympathetic ganglia. This is in contrast to the deficits reported in these neuronal populations in glial cell line-derived neurotrophic factor and Ret null mutations. Mesencephalic dopaminergic neurons in the substantia nigra and ventral tegmental area appear intact at the time of birth of the mutated mice. Mice homozygous for the GFRalpha1 null mutation die within 24 h of birth because of uremia. Heterozygous animals, however, live to adulthood. There is a significantly reduced neuroprotective effect of glial cell line-derived neurotrophic factor in such heterozygous animals, compared with wild-type littermates, after cerebral ischemia. Taken together with previous data on glial cell line-derived neurotrophic factor and Ret, our results strongly suggest that GFRalpha1 is the essential GFRalpha receptor for signaling in the glial cell line-derived neurotrophic factor-Ret pathway in the kidney and enteric nervous system development, and that GFRalpha2 or GFRalpha3 cannot substitute for the absence of GFRalpha1. Moreover, neuroprotective actions of exogenous glial cell line-derived neurotrophic factor also require full GFRalpha1 receptor expression.
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Affiliation(s)
- A C Tomac
- Laboratory of Mammalian Genes and Development, National Institutes of Health, Bethesda, MD 20892, USA
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Wang Y, Chiang YH, Su TP, Hayashi T, Morales M, Hoffer BJ, Lin SZ. Vitamin D(3) attenuates cortical infarction induced by middle cerebral arterial ligation in rats. Neuropharmacology 2000; 39:873-80. [PMID: 10699453 DOI: 10.1016/s0028-3908(99)00255-5] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.5] [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: 11/19/2022]
Abstract
We have previously reported that intracerebral administration of glial cell line derived neurotrophic factor (GDNF) reduces the extent of middle cerebral arterial (MCA) ligation-induced cortical infarction in rats. Recent studies have shown that application of 1, 25 dihydroxyvitamin D(3) (D3) enhances GDNF mRNA expression in vitro. The purpose of the present study was to investigate if administration of D3 in vivo will protect against ischemic brain injury. Adult male Sprague-Dawley rats were injected daily with D3 or with saline for four or eight days. Animals received a 90-min right MCA ligation on the 4(th) or 8(th) day after anesthesia with chloral hydrate. Animals were sacrificed for tri-phenyl-tetrazolium chloride (TTC) staining 24 h after the onset of reperfusion. A subset of animals receiving eight days of D3 or saline treatment were used for blood gas and cerebral GDNF protein level analysis. We found that pretreatment with D3 for four days did not attenuate the ischemic injury. However, animals receiving eight days of D3 injections showed a significant reduction in the amount of infarction in the cortex. Eight day D3 treatment did not alter blood gases or blood pressure; however, it did increase calcium levels. Pretreatment with D3 significantly increased GDNF levels in the cortex. In conclusion, our data indicate that D3 reduces ischemia-induced brain damage and supports the hypothesis that this effect may be through the up-regulation of GDNF mechanisms in cortex.
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Affiliation(s)
- Y Wang
- National Institute on Drug Abuse, NIH, Baltimore, MD, USA.
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Wang WY, Li MT, Pi RB, Qiu PX, Su XW, Lin SZ, Yan GM. Antagonistic action of caffeine against LY294002-induced apoptosis in cerebellar granule neurons. Acta Pharmacol Sin 2000; 21:35-40. [PMID: 11263245] [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: 02/19/2023] Open
Abstract
AIM To study the effect of caffeine on apoptosis induced by inhibition of 1-phosphatidylinositol 3-kinase in cerebellar granule neurons. METHODS Cerebellar granule neurons culture, agar gel electrophoresis, and stress-activated protein kinase (SAPK)/c-Jun N-terminal protein kinase (JNK) assay kit to measure SAPK/JNK activity. RESULTS LY294002 evoked apoptosis concentration-dependently in cerebellar granule neurons. But death resulting from LY294002 was prevented by caffeine in a concentration-dependent manner. The survival effect of caffeine was not affected by inhibitors of ryanodine-sensitive Ca2+ release, nor was it inhibited by L-type channel blockers and N-methyl-D-aspartate (NMDA) receptor blocker. In addition, RP-cAMP, H89, and KN62 were not able to inhibit the protective effect of caffeine. Phosphorylation of c-Jun was necessary for the induction of apoptosis induced by LY294002 in cerebellar granule neurons. But caffeine directly inhibited the activation of JNK and decreased phospho-c-Jun in granule neurons. CONCLUSION Caffeine inhibited the activation of JNK and decreased the phosphorylation of c-Jun to protect granule neurons from LY294002-induced apoptosis.
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Affiliation(s)
- W Y Wang
- Department of Pharmacology, Guangzhou Medical College of PLA, Guangzhou 510315, China
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Chiang YH, Lin SZ, Borlongan CV, Hoffer BJ, Morales M, Wang Y. Transplantation of fetal kidney tissue reduces cerebral infarction induced by middle cerebral artery ligation. J Cereb Blood Flow Metab 1999; 19:1329-35. [PMID: 10598937 DOI: 10.1097/00004647-199912000-00006] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The authors, and others, have recently reported that intracerebral administration of glial cell line-derived neurotrophic factor (GDNF) or osteogenic protein-1 protects against ischemia-induced injury in the cerebral cortex of adult rats. Because these trophic factors are highly expressed in the fetal, but not adult, kidney cortex, the possibility that transplantation of fetal kidney tissue could serve as a cellular reservoir for such molecules and protect against ischemic injury in cerebral cortex was examined. Fetal kidneys obtained from rat embryos at gestational day 16, and adult kidney cortex, were dissected and cut into small pieces. Adult male Sprague-Dawley rats were anesthetized with chloral hydrate and placed in a stereotactic apparatus. Kidney tissues were transplanted into three cortical areas adjacent to the right middle cerebral artery (MCA). Thirty minutes after grafting, the right MCA was transiently ligated for 90 minutes. Twenty-four hours after the onset of reperfusion, animals were evaluated behaviorally. It was found that the stroke animals that received adult kidney transplantation developed motor imbalance. However, animals that received fetal kidney grafts showed significant behavioral improvement. Animals were later sacrificed and brains were removed for triphenyltetrazolium chloride staining, Pax-2 immunostaining, and GDNF mRNA expression. It was noted that transplantation of fetal kidney but not adult kidney tissue greatly reduced the volume of infarction in the cerebral cortex. Fetal kidney grafts showed Pax-2 immunoreactivity and GDNF mRNA in the host cerebral cortex. In contrast, GDNF mRNA expression was not found in the adult kidney grafts. Taken together, our data indicate that fetal kidney transplantation reduces ischemia/reperfusion-induced cortical infarction and behavioral deficits in adult rats, and that such tissue grafts could serve as an unique cellular reservoir for trophic factor application to the brain.
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Affiliation(s)
- Y H Chiang
- Department of Neurosurgery, Tri-Service General Hospital National Defense Medical Center, Taipei, Taiwan
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Lin JJ, Yueh KC, Chang DC, Lin SZ. Absence of G209A and G88C mutations in the alpha-synuclein gene of Parkinson's disease in a Chinese population. Eur Neurol 1999; 42:217-20. [PMID: 10567818 DOI: 10.1159/000008110] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [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: 11/19/2022]
Abstract
A G209A mutation in the alpha-synuclein gene was recently discovered in a large Italian kindred and three unrelated Greek kindreds with autosomal dominant Parkinson's disease (PD). Subsequently, another mutation in the gene (G88C) was also identified in a German family with autosomal PD. These results indicate that the alpha-synuclein gene may have an important role in the pathogenesis of PD. This study was designed to screen the existence of both mutations of the alpha-synuclein gene among 100 Chinese patients with PD, including 80 with sporadic and 20 with familial PD. Results showed that none of our patients, both sporadic and familial PD, had either of the two mutations of this gene. We therefore conclude that although of great interest, these two mutations are not relevant for the pathogenesis of PD in a Han Chinese population.
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Affiliation(s)
- J J Lin
- Department of Neurology, Parkinson's Disease and Movement Disorders Clinic, Chushang Show-Chwan Hospital, Nantou, Taiwan, ROC.
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Liu DM, Lin SZ, Wang SD, Wu MY, Wang Y. Xenografting human T2 sympathetic ganglion from hyperhidrotic patients provides short-term restoration of catecholaminergic functions in hemiparkinsonian athymic rats. Cell Transplant 1999; 8:583-91. [PMID: 10701487 DOI: 10.1177/096368979900800604] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [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: 11/15/2022] Open
Abstract
Previous studies have suggested that allografting peripheral sympathetic ganglia, such as superior cervical ganglia, partially relieves clinical or behavioral deficits in parkinsonian patients and animals. However, removal of these ganglia can cause Homer's syndrome, which limits the utilization of this approach. Hyperhidrosis, a disease of excessive sweating, is commonly seen in young Orientals. Treatment of hyperhidrosis often involves surgical removal of the second thoracic sympathetic ganglia (T2G), which contain catecholaminergic neurons. The purpose of our study was to investigate behavioral responses and tyrosine hydroxylase (TH) immunoreactivity in hemiparkinsonian rats at different time points after transplantation of human T2G from hyperhidrotic patients. Athymic Fisher 344 rats were injected unilaterally with 6-hydroxydopamine into the medial forebrain bundle to destroy the nigrostriatal dopaminergic (DA) pathway. The effectiveness of lesions was tested by measuring methamphetamine (MA)-induced rotations. These unilaterally lesioned rats were later transplanted with T2G or T2 fiber tract (T2F) obtained from adult hyperhidrotic patients. Animals grafted with T2G showed a reduction in MA-induced rotation by 2 weeks; however, rotation returned to the pregrafting levels by 3 months. Animals receiving T2F grafts did not show any reduction of rotation over a 3-month period. Animals were later sacrificed for TH immunostaining at different time points. Tyrosine hydroxylase-positive [TH(+)] cell bodies and fibers were found in the lesioned striatum 2-4 weeks after T2G grafting, suggesting the survival of transplants. Two to 3 months after grafting, TH(+) fibers were still found in almost all the recipients. However, TH(+) cell bodies were found in only three of seven rats studied. Animals receiving T2F grafting did not show any TH immunoreactivity in the lesioned striatum over the 3-month period. These data indicate that T2G transplants from adult hyperhidrotic patients can survive and provide transient normalization of the motor behavior in the hemiparkinsonian athymic rats. Because of the short-term improvement in behavior after grafting, the use of T2G in human trials should be cautious at the present time. Further laboratory research is required.
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Affiliation(s)
- D M Liu
- Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
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