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Lin CT, Ting RT, Ou YH, Shao TL, Lee MC. Protein degradation of Lsd1 is mediated by Bre1 yet opposed by Lsd1-interacting lncRNAs during fly follicle development. iScience 2024; 27:109683. [PMID: 38655201 PMCID: PMC11035368 DOI: 10.1016/j.isci.2024.109683] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 02/13/2024] [Accepted: 04/04/2024] [Indexed: 04/26/2024] Open
Abstract
Tissue development, homeostasis, and repair all require efficient progenitor expansion. Lysine-specific demethylase 1 (Lsd1) maintains plastic epigenetic states to promote progenitor proliferation while overexpressed Lsd1 protein causes oncogenic gene expression in cancer cells. However, the precise regulation of Lsd1 protein expression at the molecular level to drive progenitor differentiation remains unclear. Here, using Drosophila melanogaster oogenesis as our experimental system, we discovered molecular machineries that modify Lsd1 protein stability in vivo. Through genetic and biochemical analyses, an E3 ubiquitin ligase, Bre1, was identified as required for follicle progenitor differentiation, likely by mediating Lsd1 protein degradation. Interestingly, specific Lsd1-interacting long non-coding RNAs (LINRs) were found to antagonize Bre1-mediated Lsd1 protein degradation. The intricate interplay discovered among the Lsd1 complex, LINRs and Bre1 provides insight into how Lsd1 protein stability is fine-tuned to underlie progenitor differentiation in vivo.
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Affiliation(s)
- Chun Ting Lin
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Info & Research Bldg, Rm 904, #155, Sec. 2, Li-Nong St, Taipei City 112, Taiwan
| | - Ruei-Teng Ting
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Info & Research Bldg, Rm 904, #155, Sec. 2, Li-Nong St, Taipei City 112, Taiwan
| | - Yang-Hsuan Ou
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Info & Research Bldg, Rm 904, #155, Sec. 2, Li-Nong St, Taipei City 112, Taiwan
| | - Tzu-Ling Shao
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Info & Research Bldg, Rm 904, #155, Sec. 2, Li-Nong St, Taipei City 112, Taiwan
| | - Ming-Chia Lee
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Info & Research Bldg, Rm 904, #155, Sec. 2, Li-Nong St, Taipei City 112, Taiwan
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Iguidbashian J, Lun Z, Bata K, King RW, Gunn-Sandell L, Crosby D, Stoebner K, Tharp D, Lin CT, Cumbler E, Wiler J, Yi J. Novel Electronic Health Records-Based Consultation Workflow Improves Time to Operating Room for Vascular Surgery Patients in an Acute Setting. Ann Vasc Surg 2023; 97:139-146. [PMID: 37495093 DOI: 10.1016/j.avsg.2023.07.101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/04/2023] [Accepted: 07/11/2023] [Indexed: 07/28/2023]
Abstract
BACKGROUND Inefficient clinical workflows can have downstream effects of increased costs, poor resource utilization, and worse patient outcomes. The surgical consultation process can be complex with unclear communication, potentially delaying care for patients requiring time-sensitive intervention in an acute setting. A novel electronic health records (EHR)-based workflow was implemented to improve the consultation process. After implementation, we assessed the impact of this initiative in patients requiring vascular surgery consultation. METHODS An EHR-driven consultation workflow was implemented at a single institution, standardizing the process across all consulting services. This order-initiated workflow automated notification to clinicians of consult requests, communication of patient data, patient addition to consultants' lists, and tracking consult completion. Preimplementation (1/1/2020-1/31/2022) and postimplementation (2/1/2022-12/4/2022) vascular surgery consultation cohorts were compared to evaluate the impact of this initiative on timeliness of care. RESULTS There were 554 inpatient vascular surgery consultations (255 preimplementation and 299 postimplementation); 45 and 76 consults required surgery before and after implementation, respectively. The novel workflow resulted in placement of a consult note 32 min faster than preimplementation (preimplementation: 462 min, postimplementation: 430 min, P = 0.001) for all vascular surgery consults. Furthermore, vascular surgery patients with ASA class III or IV status requiring an urgent or emergent operation were transported to the operating room 63.3% faster after implementation of the workflow (preimplementation: 284 min, postimplementation: 180 min, P = 0.02). There were no differences in procedure duration, postoperative disposition, or intraoperative complication rates. CONCLUSIONS We implemented a novel workflow utilizing the EHR to standardize and automate the consultation process in the acute inpatient setting. This institutional initiative significantly improved timeliness of care for vascular surgery patients, including decreased time to operation. Innovations such as this can be further disseminated across shared EHR platforms across institutions, representing a powerful tool to increase the value of care in vascular surgery and healthcare overall.
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Affiliation(s)
- John Iguidbashian
- Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, CO.
| | - Zhixin Lun
- Department of Biostatistics, Center of Innovative Design and Analysis, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Kyle Bata
- Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Robert W King
- Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Lauren Gunn-Sandell
- Department of Biostatistics, Center of Innovative Design and Analysis, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Derek Crosby
- Division of Vascular Medicine, University of Colorado Health, Aurora, CO
| | - Kristin Stoebner
- Division of Vascular Medicine, University of Colorado Health, Aurora, CO
| | - David Tharp
- Division of Vascular Medicine, University of Colorado Health, Aurora, CO
| | - C T Lin
- Department of Medicine, University of Colorado, Aurora, CO
| | - Ethan Cumbler
- Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, CO; Department of Medicine, University of Colorado, Aurora, CO
| | - Jennifer Wiler
- Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Jeniann Yi
- Division of Vascular Surgery and Endovascular Therapy, University of Colorado Anschutz Medical Campus, Aurora, CO
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Abstract
Fuzzy membership is an effective approach used in twin support vector machines (SVMs) to reduce the effect of noise and outliers in classification problems. Fuzzy twin SVMs (TWSVMs) assign membership weights to reduce the effect of outliers, however, it ignores the positioning of the input data samples and hence fails to distinguish between support vectors and noise. To overcome this issue, intuitionistic fuzzy TWSVM combined the concept of intuitionistic fuzzy number with TWSVMs to reduce the effect of outliers and distinguish support vectors from noise. Despite these benefits, TWSVMs and intuitionistic fuzzy TWSVMs still suffer from some drawbacks as: 1) the local neighborhood information is ignored among the data points and 2) they solve quadratic programming problems (QPPs), which is computationally inefficient. To overcome these issues, we propose a novel intuitionistic fuzzy weighted least squares TWSVMs for classification problems. The proposed approach uses local neighborhood information among the data points and also uses both membership and nonmembership weights to reduce the effect of noise and outliers. The proposed approach solves a system of linear equations instead of solving the QPPs which makes the model more efficient. We evaluated the proposed intuitionistic fuzzy weighted least squares TWSVMs on several benchmark datasets to show the efficiency of the proposed model. Statistical analysis is done to quantify the results statistically. As an application, we used the proposed model for the diagnosis of Schizophrenia disease.
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Chalmers T, Maharaj S, Lees T, Lin CT, Newton P, Clifton-Bligh R, McLachlan CS, Gustin SM, Lal S. Impact of acute stress on cortical electrical activity and cardiac autonomic coupling. J Integr Neurosci 2021; 19:239-248. [PMID: 32706188 DOI: 10.31083/j.jin.2020.02.74] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 06/17/2020] [Indexed: 11/06/2022] Open
Abstract
Assessment of heart rate variability (reflective of the cardiac autonomic nervous system) has shown some predictive power for stress. Further, the predictive power of the distinct patterns of cortical brain activity and - cardiac autonomic interactions are yet to be explored in the context of acute stress, as assessed by an electrocardiogram and electroencephalogram. The present study identified distinct patterns of neural-cardiac autonomic coupling during both resting and acute stress states. In particular, during the stress task, frontal delta waves activity was positively associated with low-frequency heart rate variability and negatively associated with high-frequency heart rate variability. Low high-frequency power is associated with stress and anxiety and reduced vagal control. A positive association between resting high-frequency heart rate variability and frontocentral gamma activity was found, with a direct inverse relationship of low-frequency heart rate variability and gamma wave coupling at rest. During the stress task, low-frequency heart rate variability was positively associated with frontal delta activity. That is, the parasympathetic nervous system is reduced during a stress task, whereas frontal delta wave activity is increased. Our findings suggest an association between cardiac parasympathetic nervous system activity and frontocentral gamma and delta activity at rest and during acute stress. This suggests that parasympathetic activity is decreased during acute stress, and this is coupled with neuronal cortical prefrontal activity. The distinct patterns of neural-cardiac coupling identified in this study provide a unique insight into the dynamic associations between brain and heart function during both resting and acute stress states.
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Affiliation(s)
- Taryn Chalmers
- Neuroscience Research Unit, School of Technology Sydney, PO Box 123, Australia
| | - Shamona Maharaj
- Neuroscience Research Unit, School of Technology Sydney, PO Box 123, Australia
| | - Ty Lees
- Edna Bennett Pierce Prevention Research Center, Pennsylvania State University, PA, 16802, USA
| | - C T Lin
- Computational Intelligence and Brain Computer Interface Centre (CIBCI), Faculty of Engineering and Information Technology (FEIT), University of Technology Sydney, PO Box 123, Australia
| | - Phillip Newton
- School of Nursing and Midwifery, Western Sydney University, Locked Bag 1797, Penrith NSW 2751, Australia
| | - Roderick Clifton-Bligh
- Medicine, Kolling Institute of Medical Research, Northern Clinical School, University of Sydney, NSW 2065, Australia
| | - Craig S McLachlan
- Centre for Healthy Futures, Health Faculty, Pyrmont Campus, Sydney, Torrens University Australia, NSW 2009, Australia
| | - Sylvia M Gustin
- School of Psychology, University of New South Wales, Sydney, NSW 2052, Australia.,Neuroscience Research Australia, Sydney, NSW 2031, Australia
| | - Sara Lal
- Neuroscience Research Unit, School of Technology Sydney, PO Box 123, Australia
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Chen YM, Hung WT, Liao YW, Hsu CY, Hsieh TY, Chen HH, Hsieh CW, Lin CT, Lai KL, Tang KT, Tseng CW, Huang WN, Chen YH. Combination immunosuppressant therapy and lupus nephritis outcome: a hospital-based study. Lupus 2019; 28:658-666. [PMID: 30971165 DOI: 10.1177/0961203319842663] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Lupus nephritis (LN) is the leading cause of mortality in lupus patients. This study aimed to investigate the treatment outcome and renal histological risk factors of LN in a tertiary referral center. Between 2006 and 2017, a retrospective observational study enrolled 148 biopsy-proven LN patients. After propensity score matching, 75 cases were included for further analysis. The classification and scoring of LN were assessed according to the International Society of Nephrology/Renal Pathology Society. Treatment response was evaluated by daily urine protein and urinalysis at two years after commencing induction treatment and the development of end-stage renal disease (ESRD). In total, 50.7% patients achieved complete remission (CR) or partial remission (PR), while 49.3% patients were categorized as nonresponders. Therapeutic responses in terms of CR/PR rates were associated with Systemic Lupus Erythematosus Disease Activity Index scores (odds ratio (OR): 1.34, 95% confidence interval (CI): 1.12-1.60, p = 0.001). Moreover, higher baseline creatinine levels (hazard ratio (HR): 2.10, 95% CI: 1.29-3.40, p = 0.003), higher renal activity index (HR: 1.30, 95% CI: 1.07-1.58, p = 0.008) and chronicity index (HR: 1.40, 95% CI: 1.06-1.85, p = 0.017) predicted ESRD. Among pathological scores, cellular crescents (HR: 4.42, 95% CI: 1.01-19.38, p = 0.049) and fibrous crescents (HR: 5.93, 95% CI: 1.41-24.92, p = 0.015) were independent risk factors for ESRD. In conclusion, higher lupus activity was a good prognostic marker for renal remission. Renal histology was predictive of ESRD. Large-scale prospective studies are required to verify the efficacy of mycophenolate in combination with azathioprine or cyclosporine in LN patients.
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Affiliation(s)
- Y M Chen
- 1 Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung.,2 Department of Medical Research, Taichung Veterans General Hospital, Taichung.,3 Faculty of Medicine, National Yang-Ming University, Taipei.,4 Institute of Biomedical Science and Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung
| | - W T Hung
- 1 Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung.,5 Department of Medical Education, Taichung Veterans General Hospital, Taichung.,6 Institute of Clinical Medicine, National Yang-Ming University, Taipei
| | - Y W Liao
- 1 Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung
| | - C Y Hsu
- 2 Department of Medical Research, Taichung Veterans General Hospital, Taichung
| | - T Y Hsieh
- 1 Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung.,5 Department of Medical Education, Taichung Veterans General Hospital, Taichung
| | - H H Chen
- 1 Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung.,2 Department of Medical Research, Taichung Veterans General Hospital, Taichung.,3 Faculty of Medicine, National Yang-Ming University, Taipei.,4 Institute of Biomedical Science and Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung
| | - C W Hsieh
- 1 Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung.,5 Department of Medical Education, Taichung Veterans General Hospital, Taichung
| | - C T Lin
- 1 Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung
| | - K L Lai
- 1 Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung
| | - K T Tang
- 1 Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung
| | - C W Tseng
- 1 Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung
| | - W N Huang
- 1 Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung.,3 Faculty of Medicine, National Yang-Ming University, Taipei
| | - Y H Chen
- 1 Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung.,3 Faculty of Medicine, National Yang-Ming University, Taipei
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Li MT, Fang YF, Sun Z, Zhang JC, Lin CT. Evidence for weak collective pinning and δl pinning in topological superconductor Cu x Bi 2Se 3. J Phys Condens Matter 2018; 30:31LT01. [PMID: 29947615 DOI: 10.1088/1361-648x/aacf6a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We investigated the vortex pinning behavior in the single crystal topological superconductor Cu0.10Bi2Se3 with a pronounced anisotropic peak effect. A weak collective pinning regime is clarified from the power-law behavior in [Formula: see text] and the small critical current density ratio of [Formula: see text] ~ 10-5 ([Formula: see text] is the critical current density, [Formula: see text] is the depairing current density). The spatial variation of the charge-carrier mean free path induced pinning is evidenced and probably results from the well-defined atomic defects. Within the framework of collective pinning theory, we computed the values of the correlated length and volume at 1.8 K, which start declining prior to the onset field of the peak effect [Formula: see text], demonstrating the vortex lattices already suffered a preferential collapse ahead of the peak effect turns up. Thus, the peak effect can be understood by elastic moduli softening near the upper critical field [Formula: see text]. We suggest Cu x Bi2Se3 is a prototype topological material for investigating the vortex pinning dynamics associated with the peak effect phenomenon.
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Affiliation(s)
- M T Li
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany. Materials Genome Institute and Department of Physics, Shanghai University, Shanghai 200444, People's Republic of China
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7
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Li MT, Fang YF, Zhang JC, Yi HM, Zhou XJ, Lin CT. Magnetotransport study of topological superconductor Cu 0.10Bi 2Se 3 single crystal. J Phys Condens Matter 2018; 30:125702. [PMID: 29485100 DOI: 10.1088/1361-648x/aaaca1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report a magnetotransport study of vortex-pinning in Cu0.10Bi2Se3 single crystal. The sample is demonstrated to be in clean limit and absent of Pauli spin-limiting effect. Interestingly, the resistivity versus magnetic field shows an anomalously pronounced increase when approaching the superconducting-normal state boundary for both [Formula: see text] and [Formula: see text] configurations. We have investigated the flux-flowing behavior under various magnetic fields and temperatures, enabling us to establish its anisotropic vortex phase diagram. Our results suggest the Cu0.10Bi2Se3 can be served as one unique material for exploring exotic surface vortex states in topological superconductors.
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Affiliation(s)
- M T Li
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany. Materials Genome Institute and Department of Physics, Shanghai University, Shanghai 200444, People's Republic of China
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8
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Zhu GY, Lin CT, Chen JM, Lei DM, Zhu GX. The study of size and stability of n-butylcyanoacrylate nanocapsule suspensions encapsulating green grass fragrance. ACTA ACUST UNITED AC 2018. [DOI: 10.1088/1757-899x/292/1/012094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kawasaki S, Li Z, Kitahashi M, Lin CT, Kuhns PL, Reyes AP, Zheng GQ. Charge-density-wave order takes over antiferromagnetism in Bi 2Sr 2-x La x CuO 6 superconductors. Nat Commun 2017; 8:1267. [PMID: 29097672 PMCID: PMC5668353 DOI: 10.1038/s41467-017-01465-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [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: 06/02/2017] [Accepted: 09/19/2017] [Indexed: 11/17/2022] Open
Abstract
Superconductivity appears in the cuprates when a spin order is destroyed, while the role of charge is less known. Recently, charge density wave (CDW) was found below the superconducting dome in YBa2Cu3Oy when a high magnetic field is applied perpendicular to the CuO2 plane, which was suggested to arise from incipient CDW in the vortex cores that becomes overlapped. Here by 63Cu-nuclear magnetic resonance, we report the discovery of CDW induced by an in-plane field, setting in above the dome in single-layered Bi2Sr2−xLaxCuO6. The onset temperature TCDW takes over the antiferromagnetic order temperature TN beyond a critical doping level at which superconductivity starts to emerge, and scales with the pseudogap temperature T*. These results provide important insights into the relationship between spin order, CDW and the pseudogap, and their connections to high-temperature superconductivity. Whilst superconductivity usually appears when magnetic order is suppressed, the role of charge is less known. Here, Kawasaki et al. report a charge density wave (CDW) above the superconducting transition induced by an in-plane magnetic field in Bi2Sr2-xLaxCuO6, with the CDW onset temperature scaling with the pseudogap temperature.
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Affiliation(s)
- S Kawasaki
- Department of Physics, Okayama University, Okayama, 700-8530, Japan
| | - Z Li
- Institute of Physics, Chinese Academy of Sciences, and Beijing National Laboratory for Condensed Matter Physics, 100190, Beijing, China
| | - M Kitahashi
- Department of Physics, Okayama University, Okayama, 700-8530, Japan
| | - C T Lin
- Max-Planck-Institut fur Festkorperforschung, Heisenbergstrasse 1, D-70569, Stuttgart, Germany
| | - P L Kuhns
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - A P Reyes
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Guo-Qing Zheng
- Department of Physics, Okayama University, Okayama, 700-8530, Japan. .,Institute of Physics, Chinese Academy of Sciences, and Beijing National Laboratory for Condensed Matter Physics, 100190, Beijing, China.
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10
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Liu ZH, Yaresko AN, Li Y, Dai PC, Zhang H, Büchner B, Lin CT, Borisenko SV. Observation of the weak electronic correlations in KFeCoAs 2 (3d 6): an isoelectronic to the parent compounds of 122 series of iron pnictides BaFe 2As 2. J Phys Condens Matter 2017; 29:085503. [PMID: 27991428 DOI: 10.1088/1361-648x/aa5486] [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: 06/06/2023]
Abstract
Using the angle-resolved photoemission spectroscopy and band structure calculations we study the electronic structure of KFeCoAs2, which is isoelectronic to the parent material of 122 series of iron-based superconductors BaFe2As2. Although band structure calculations predict nearly identical dispersions of the electronic states in both compounds, experiment reveals drastic differences in both the global renormalization and Fermi surfaces. On the basis of the comparison of electronic structures of these two isoelectronic compounds, we demonstrate local magnetic correlations as a vital role for the peculiar low-energy electron dynamics of iron-based superconductors.
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Affiliation(s)
- Z H Liu
- Institute for Solid State Research, IFW Dresden, D-01171 Dresden, Germany. State Key Laboratory of Functional Materials for Informatic, SIMIT, Chinese Academy of Sciences, Shanghai 200050, People's Repubic of China
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11
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Affiliation(s)
- Zuzanna Czernik
- Hospital Medicine Section, Division of General Internal Medicine, University of Colorado School of Medicine, Aurora
| | - C T Lin
- Division of General Internal Medicine, University of Colorado School of Medicine, Aurora
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12
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Yu G, Zhang GY, Ryu GH, Lin CT. Structure and superconductivity of (Li1-x Fe x )OHFeSe single crystals grown using A x Fe2-y Se2 (A = K, Rb, and Cs) as precursors. J Phys Condens Matter 2016; 28:015701. [PMID: 26656943 DOI: 10.1088/0953-8984/28/1/015701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present results on the hydrothermal growth of ([Formula: see text])OHFeSe single crystals using floating-zone-grown [Formula: see text] (A = K, Rb, and Cs) as precursors. The growth proceeds by the hydrothermal ion exchange of Li/Fe-O-H for K, Rb, and Cs, resulting in a stacking layer of ([Formula: see text])OH sandwiched between the FeSe layers. Optimal growth parameters are achieved using high quality A 0.80Fe1.81Se2 single crystals added to the mixtures of LiOH, H2O, Fe and C(NH2)2Se in an autoclave and subsequently heated to 120 °C for 2 d, to obtain highest quality single crystals. The obtained crystals have lateral dimensions up to centimeters, with the final size related to that of the precursor crystal used. All ([Formula: see text])OHFeSe single crystals show a superconducting transition temperature T c > 42 K, regardless of the phase of the precursor such as superconducting K0.80Fe1.81Se2 (T c = 29.31 K) or non-superconducting Rb0.80Fe1.81Se2 or poor-superconducting Cs0.80Fe1.81Se2 (T c = 28.67 K). The T c and transition width ΔT vary in the obtained single crystals, due to the inhomogeneity of the ionic exchange. X-ray diffraction analysis demonstrates that the 245 insulating phase is absent in the ion-exchanged single crystals, while it is observed in the [Formula: see text] precursors. Comparative studies of the structure, magnetization, and superconductivity on the parent A 0.80Fe1.81Se2 and the ion-exchanged ([Formula: see text])OHFeSe crystals are discussed. A phase diagram including antiferromagnetic spin density wave and superconducting phases is also proposed.
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Affiliation(s)
- G Yu
- Max Planck Institute for Solid State Research, D 70569 Stuttgart, Germany. Shijiazhuang Tiedao University, Shijiazhuang 050043, People's Republic of China
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Lin WT, Chang CH, Cheng CY, Chen MC, Wen YR, Lin CT, Lin CW. Effects of low amplitude pulsed radiofrequency stimulation with different waveform in rats for neuropathic pain. Annu Int Conf IEEE Eng Med Biol Soc 2015; 2013:3590-3. [PMID: 24110506 DOI: 10.1109/embc.2013.6610319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Pulsed-radiofrequency (PRF) electrical stimulation has been widely used for chronic pain treatment. It has been demonstrated with advantages of low temperature over traditional continuous radiofrequency (CRF) lesions with higher amplitude and mono polar electrode to treat pain in clinics (frequency 500 KHz, Pulse duration 20 msec, Amplitude 45 V, Treatment 2 min). We compare the effects of different pulse waveforms and PRF parameters (Pulse duration 25 ms, Treatment duration 5 min, low amplitude of 2.5/1.25 V) with a miniature bi-polar electrode on Dorsal root ganglion (DRG). The pain relief effect due to PRF is evaluated by using Von Frey method for the pain threshold index based on behavior response to mechanical stimulus of various strengths. Experimental results of Von Frey Score show that the sinusoidal group has higher responses than the square wave one. Both fast and secondary expressed proteins of c-fos and pp38 are measured from spinal cord tissue sectioning slides to characterize the pain associated inflammatory responses and their responses due to PRF stimulation.
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Hsueh WJ, Chang CH, Lin CT. Exciton photoluminescence in resonant quasi-periodic Thue-Morse quantum wells. Opt Lett 2014; 39:489-492. [PMID: 24487847 DOI: 10.1364/ol.39.000489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This Letter investigates exciton photoluminescence (PL) in resonant quasi-periodic Thue-Morse quantum wells (QWs). The results show that the PL properties of quasi-periodic Thue-Morse QWs are quite different from those of resonant Fibonacci QWs. The maximum and minimum PL intensities occur under the anti-Bragg and Bragg conditions, respectively. The maxima of the PL intensity gradually decline when the filling factor increases from 0.25 to 0.5. Accordingly, the squared electric field at the QWs decreases as the Thue-Morse QW deviates from the anti-Bragg condition.
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Li Y, Le Tacon M, Matiks Y, Boris AV, Loew T, Lin CT, Chen L, Chan MK, Dorow C, Ji L, Barišić N, Zhao X, Greven M, Keimer B. Doping-dependent photon scattering resonance in the model high-temperature superconductor HgBa2CuO4+δ revealed by Raman scattering and optical ellipsometry. Phys Rev Lett 2013; 111:187001. [PMID: 24237551 DOI: 10.1103/physrevlett.111.187001] [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: 06/19/2013] [Indexed: 06/02/2023]
Abstract
We study the model high-temperature superconductor HgBa(2)CuO(4+δ) with electronic Raman scattering and optical ellipsometry over a wide doping range. The dependence of the resonant Raman cross section on the incident photon energy changes drastically as a function of doping, in a manner that corresponds to a rearrangement of the interband optical transitions seen with ellipsometry. This doping-dependent Raman resonance allows us to reconcile the apparent discrepancy between Raman and x-ray detection of magnetic fluctuations in superconducting cuprates. Intriguingly, the strongest variation occurs across the doping level where the antinodal superconducting gap appears to reach its maximum.
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Affiliation(s)
- Yuan Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China and Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany
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Li MT, Chen L, Li ZW, Ryu GH, Lin CT, Zhang JC. Enhancement of phase separation and superconductivity in Mn-doped K0.8Fe2-yMnySe2 crystals. J Phys Condens Matter 2013; 25:335701. [PMID: 23880791 DOI: 10.1088/0953-8984/25/33/335701] [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: 06/02/2023]
Abstract
Single crystals of K0.8Fe2-yMnySe2 with slight Mn doping have been grown by a self-flux method. X-ray diffraction measurements show enhanced phase separation with increasing Mn doping in the compounds. The superconducting transition temperature increases to Tc,onset ∼ 46.1 K for the sample with y ∼ 0.03, as observed by electrical transport measurements. Our results demonstrate that the doping of Mn does not suppress the superconductivity, and on the contrary increases the superconducting shield fraction and transition temperature, an effect which may originate from the Mn dopant's high preference to fill into iron vacancies in the Mn-doped samples. It suggests that the Mn dopant can induce a local lattice strain or distortion that profitably modifies the microstructure of the superconducting/metallic phase, leading to superconductivity of the compound.
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Affiliation(s)
- M T Li
- Department of Physics, Shanghai University, Shanghai 200444, People's Republic of China
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17
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Raichle M, Reznik D, Lamago D, Heid R, Li Y, Bakr M, Ulrich C, Hinkov V, Hradil K, Lin CT, Keimer B. Highly anisotropic anomaly in the dispersion of the copper-oxygen bond-bending phonon in superconducting YBa2Cu3O7 from inelastic neutron scattering. Phys Rev Lett 2011; 107:177004. [PMID: 22107567 DOI: 10.1103/physrevlett.107.177004] [Citation(s) in RCA: 3] [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: 05/03/2011] [Indexed: 05/31/2023]
Abstract
Motivated by predictions of a substantial contribution of the "buckling" vibration of the CuO(2) layers to d-wave superconductivity in the cuprates, we have performed an inelastic neutron scattering study of this phonon in an array of untwinned crystals of YBa(2)Cu(3)O(7). The data reveal a pronounced softening of the phonon at the in-plane wave vector q=(0,0.3) upon cooling below ~105 K, but no corresponding anomaly at q=(0.3,0). Based on the observed in-plane anisotropy, we argue that the electron-phonon interaction responsible for this anomaly supports an electronic instability associated with a uniaxial charge-density modulation and does not mediate d-wave superconductivity.
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Affiliation(s)
- M Raichle
- Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany
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18
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Yeoh WK, Gault B, Cui XY, Zhu C, Moody MP, Li L, Zheng RK, Li WX, Wang XL, Dou SX, Sun GL, Lin CT, Ringer SP. Direct observation of local potassium variation and its correlation to electronic inhomogeneity in (Ba(1-x)K(x))Fe2As2 pnictide. Phys Rev Lett 2011; 106:247002. [PMID: 21770591 DOI: 10.1103/physrevlett.106.247002] [Citation(s) in RCA: 7] [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: 02/28/2011] [Indexed: 05/31/2023]
Abstract
Local fluctuations in the distribution of dopant atoms are thought to cause the nanoscale electronic disorder or phase separation in pnictide superconductors. Atom probe tomography has enabled the first direct observations of dopant species clustering in a K-doped 122-phase pnictide. First-principles calculations suggest the coexistence of static magnetism and superconductivity on a lattice parameter length scale over a wide range of dopant concentrations. Our results provide evidence for a mixed scenario of phase coexistence and phase separation, depending on local dopant atom distributions.
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Affiliation(s)
- W K Yeoh
- Australian Centre for Microscopy & Microanalysis, University of Sydney, Sydney, New South Wales, Australia.
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19
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Felea V, Lemmens P, Yasin S, Zherlitsyn S, Choi KY, Lin CT, Payen C. Magnetic phase diagram of multiferroic MnWO4 probed by ultrasound. J Phys Condens Matter 2011; 23:216001. [PMID: 21555835 DOI: 10.1088/0953-8984/23/21/216001] [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: 05/30/2023]
Abstract
The magnetic phase diagram of multiferroic MnWO(4) is studied in magnetic fields up to 60 T using sound velocity and sound attenuation measurements. Anomalies are observed at temperatures T(N1) = 7.6 K, T(N2) = 12.6 K and T(N3) = 13.6 K that separate commensurate antiferromagnetic (AF1) to helical AF2 and commensurate AF3 to paramagnetic phases, respectively. The anomalies are significantly different and shed light on the spin-phonon coupling and evolution of the various order parameters in this multiferroic material. For temperatures below T(N2) pronounced field hysteresis effects are also observed in the sound velocity, indicating field-induced transformations. In the temperature dependence of the attenuation we observe anomalies distinctively different from the usual maxima related to relaxation effects. They are attributed to the combination of dispersion effects due to domain walls and the discontinuously changing sound velocity. In total, six different magnetic phases, at various temperatures and fields including a novel high-field phase, are revealed and analyzed.
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Affiliation(s)
- V Felea
- Institute for Condensed Matter Physics, TU Braunschweig, Braunschweig, Germany
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20
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Dubroka A, Rössle M, Kim KW, Malik VK, Munzar D, Basov DN, Schafgans AA, Moon SJ, Lin CT, Haug D, Hinkov V, Keimer B, Wolf T, Storey JG, Tallon JL, Bernhard C. Evidence of a precursor superconducting phase at temperatures as high as 180 K in RBa2Cu3O(7-δ) (R=Y, Gd, Eu) superconducting crystals from infrared spectroscopy. Phys Rev Lett 2011; 106:047006. [PMID: 21405352 DOI: 10.1103/physrevlett.106.047006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Indexed: 05/30/2023]
Abstract
We show that a multilayer analysis of the infrared c-axis response of RBa2Cu3O(7-δ) (R=Y, Gd, Eu) provides important new information about the anomalous normal-state properties of underdoped cuprate high temperature superconductors. In addition to competing correlations which give rise to a pseudogap that depletes the low-energy electronic states below T*≫T(c), it enables us to identify the onset of a precursor superconducting state below T(ons)>T(c). We map out the doping phase diagram of T(ons) which reaches a maximum of 180 K at strong underdoping and present magnetic field dependent data which confirm our conclusions.
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Affiliation(s)
- A Dubroka
- University of Fribourg, Department of Physics, Fribourg, Switzerland
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21
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Lin CT, Huang TW, Lee SC, Kuo SM, Hsu KF, Hsu PS, Huang HK, Chang H. Sengstaken-Blakemore tube related esophageal rupture. Rev Esp Enferm Dig 2010; 102:395-6. [PMID: 20575606 DOI: 10.4321/s1130-01082010000600014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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22
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Affiliation(s)
- C T Lin
- Division of Colon and Rectal Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
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Hsu KF, Lin CT, Wu CC, Hsiao CW, Lee TY, Mai CM, Jin JS, Jao SW. Schwannoma of the rectum: report of a case and review of the literature. Rev Esp Enferm Dig 2010; 102:289-91. [PMID: 20486757 DOI: 10.4321/s1130-01082010000400016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Suchaneck A, Hinkov V, Haug D, Schulz L, Bernhard C, Ivanov A, Hradil K, Lin CT, Bourges P, Keimer B, Sidis Y. Incommensurate magnetic order and dynamics induced by spinless impurities in YBa(2)Cu(3)O(6.6). Phys Rev Lett 2010; 105:037207. [PMID: 20867803 DOI: 10.1103/physrevlett.105.037207] [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: 04/01/2010] [Revised: 05/15/2010] [Indexed: 05/29/2023]
Abstract
We report an inelastic-neutron-scattering and muon-spin-relaxation study of the effect of 2% spinless (Zn) impurities on the magnetic order and dynamics of YBa(2)Cu(3)O(6.6), an underdoped high-temperature superconductor that exhibits a prominent spin pseudogap in its normal state. Zn substitution induces static magnetic order at low temperatures and triggers a large-scale spectral-weight redistribution from the magnetic resonant mode at 38 meV into uniaxial, incommensurate spin excitations with energies well below the spin pseudogap. These observations indicate a competition between incommensurate magnetic order and superconductivity close to a quantum critical point. Comparison to prior data on La(2-x)Sr(x)CuO(4) suggests that this behavior is universal for the layered copper oxides and analogous to impurity-induced magnetic order in one-dimensional quantum magnets.
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Affiliation(s)
- A Suchaneck
- Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany
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25
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Lin CT, Cha TL, Wu ST, Chuang FP. Acute fulminant colon cancer metastasis after renal transplantation. Rev Esp Enferm Dig 2010; 102:447-8. [PMID: 20617867 DOI: 10.4321/s1130-01082010000700009] [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: 11/11/2022]
Abstract
We report a 52-year-old male with no family history of colonic cancer, who was found to have advanced colonic cancer with metastases two months post renal transplantation. With this case, we highlight the possibility of acute fulminant cancer metastases within short period after renal transplantation and the importance of periodic colorectal cancer screening pre-transplant. To our knowledge, this case is not yet reported in the literature, especially with such presentation of acute fulminant colonic cancer metastases post renal transplantation.
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Affiliation(s)
- C T Lin
- Division of Urology, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
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26
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Popovich P, Boris AV, Dolgov OV, Golubov AA, Sun DL, Lin CT, Kremer RK, Keimer B. Specific heat measurements of Ba(0.68)K(0.32)Fe2As2 single crystals: evidence for a multiband strong-coupling superconducting state. Phys Rev Lett 2010; 105:027003. [PMID: 20867730 DOI: 10.1103/physrevlett.105.027003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Indexed: 05/29/2023]
Abstract
The specific heat of high-purity Ba(0.68)K(0.32)Fe2As2 single crystals with the highest reported superconducting Tc=38.5 K was studied. The electronic specific heat Cp below Tc shows two gap features, with Δ1≈11 meV and Δ2≈3.5 meV obtained from an α-model analysis. The reduced gap value, 2Δ(max)/kBTc≈6.6, the magnitude of the specific-heat jump, ΔCp(Tc)/Tc, and its slope below Tc exhibit a strong-coupling character. We also show that an Eliashberg model with two hole and two electron bands gives the correct values of Tc, the superconducting gaps, and the free-energy difference.
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Affiliation(s)
- P Popovich
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
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27
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Abstract
The presence of a biphasic circular dichroism (CD) observed in the visible absorption spectrum of retinal in bacteriorhodopsin (bR) has been believed for many years to be due to excitonic-type interaction within the trimeric structure of the retinal in the protein membrane. In the present work, we present data and discuss previous observations that strongly suggest the absence of such an excitonic interaction. The magnetic CD spectrum of the trimer is found to be similar to that of the monomer and shows no sign of absorption to the doubly degenerate state predicted to be present from the exciton theory. This, together with the previous observations on the CD spectra of the photocycle intermediates of bR as well as the linear polarization studies of the fluorescence and the daughter absorption, sheds doubt on the presence of exciton interaction and thus suggests the presence of neither an antenna system nor a viable special reaction center in bR. Possible explanation for the observed biphasic nature of the CD spectrum is given in terms of having more than one type of bR with different protein conformations around the retinals in the trimer giving each similar absorption maximum but opposite signs for its rotary dispersion power.
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Affiliation(s)
- M A El-Sayed
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA 90024
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28
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Abstract
A recurrent self-organizing neural fuzzy inference network (RSONFIN) is proposed in this paper. The RSONFIN is inherently a recurrent multilayered connectionist network for realizing the basic elements and functions of dynamic fuzzy inference, and may be considered to be constructed from a series of dynamic fuzzy rules. The temporal relations embedded in the network are built by adding some feedback connections representing the memory elements to a feedforward neural fuzzy network. Each weight as well as node in the RSONFIN has its own meaning and represents a special element in a fuzzy rule. There are no hidden nodes (i.e., no membership functions and fuzzy rules) initially in the RSONFIN. They are created on-line via concurrent structure identification (the construction of dynamic fuzzy if-then rules) and parameter identification (the tuning of the free parameters of membership functions). The structure learning together with the parameter learning forms a fast learning algorithm for building a small, yet powerful, dynamic neural fuzzy network. Two major characteristics of the RSONFIN can thus be seen: 1) the recurrent property of the RSONFIN makes it suitable for dealing with temporal problems and 2) no predetermination, like the number of hidden nodes, must be given, since the RSONFIN can find its optimal structure and parameters automatically and quickly. Moreover, to reduce the number of fuzzy rules generated, a flexible input partition method, the aligned clustering-based algorithm, is proposed. Various simulations on temporal problems are done and performance comparisons with some existing recurrent networks are also made. Efficiency of the RSONFIN is verified from these results.
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Affiliation(s)
- C F Juang
- Department of Electrical and Control Engineering, National Chiao-Tung University, Hsinchu, Taiwan, R.O.C
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Lin CT, Hsu KF, Hong ZJ, Yu JC, Hsieh CB, Chan DC, Shih ML, Liao GS. A paraduodenal hernia (Treitz's hernia) causing acute bowel obstruction. Rev Esp Enferm Dig 2010; 102:220-1. [PMID: 20373840 DOI: 10.4321/s1130-01082010000300014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lin CT, Hsu KF, Hsu PS, Wu CC, Kuo SM, Fu CY, Hong ZJ, Jao SW. Co-existing primary intra-abdominal and pelvic myxoid liposarcomas: report of a case. Rev Esp Enferm Dig 2010; 102:284-5. [PMID: 20486753 DOI: 10.4321/s1130-01082010000400012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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31
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Choi KY, Lemmens P, Eremin I, Zwicknagl G, Berger H, Sun GL, Sun DL, Lin CT. Self-energy effects and electron-phonon coupling in Fe-As superconductors. J Phys Condens Matter 2010; 22:115802. [PMID: 21389475 DOI: 10.1088/0953-8984/22/11/115802] [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] [Indexed: 05/30/2023]
Abstract
Doping and temperature dependent studies of optical phonon modes in Fe-122 pnictides are performed using Raman scattering experiments and compared with model calculations to elucidate the role of electron-phonon and spin-phonon interaction in this family of compounds. The frequency and linewidth of the B(1g) mode at around 210 cm(-1) is highlighted as appreciable anomalies at the superconducting and spin density wave transitions are observed that strongly depend on composition. We give estimates of the electron-phonon coupling related to this renormalization and calculate the phonon self-energy on the basis of a four-band model comparing different symmetries of the order parameters. In addition, we observe a pronounced quasi-elastic Raman response for the undoped compound, suggesting persisting magnetic fluctuations in the spin density wave state.
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Affiliation(s)
- K-Y Choi
- Institute for Condensed Matter Physics, TU Braunschweig, D-38106 Braunschweig, Germany
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32
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Lo YJ, Chang WJ, Lee SY, Chang KJ, Lin CT, Huang HM. Reductions in the effects of damping on stress concentration in premolars by post-endodontic restorations: a non-linear finite element study. Proc Inst Mech Eng H 2009; 223:555-65. [PMID: 19623909 DOI: 10.1243/09544119jeim538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The aim of this study was to measure the structural damping constants of premolars after treatment with a cast Co-Cr post-core system or permanent root filling, and to evaluate the stress damping effects of these restored premolars. Both the damping ratio and the natural frequency (NF) of the cast Co-Cr post-core restored premolars and the permanent root-filled premolars were detected by in-vitro NF testing experiments. Unprepared premolars served as the control. The damping constants beta of the samples were calculated from the measured damping ratios and natural frequencies. The measured damping constants beta of the test premolars were then used for dynamic finite element (FE) analyses. Stress contours and damping effects of stresses in each treated type of premolar were computed and compared using ANSYS. The measured damping constants beta were 0.75 x 10(-5) for the unprepared premolars, 0.69 x 10(-5) for the root-filled premolars with coronal restoration, and 0.72 x 10(-5) for the cast Co-Cr post-core restored premolars. The unprepared intact premolars demonstrated the highest stress dissipation effects with a ratio of 29.3 per cent at the middle root opposite to the loading side. However, no stress dissipation effects were found in the premolars that had been restored with the cast Co-Cr post-core system. The FE analysis showed that metallic post treatment attenuated the damping properties of the premolar. The effects of damping on stress concentration were significantly lower in restored premolars than in untreated vital premolars. These findings suggest that future research on post material should take the damping property into consideration.
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Affiliation(s)
- Y J Lo
- Dental Department of Wan-Fang Hospital, Taipei Medical University, Taipei, Republic of China
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33
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Haug D, Hinkov V, Suchaneck A, Inosov DS, Christensen NB, Niedermayer C, Bourges P, Sidis Y, Park JT, Ivanov A, Lin CT, Mesot J, Keimer B. Magnetic-field-enhanced incommensurate magnetic order in the underdoped high-temperature superconductor YBa2Cu3O6.45. Phys Rev Lett 2009; 103:017001. [PMID: 19659170 DOI: 10.1103/physrevlett.103.017001] [Citation(s) in RCA: 7] [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: 01/21/2009] [Indexed: 05/28/2023]
Abstract
We present a neutron-scattering study of the static and dynamic spin correlations in the underdoped high-temperature superconductor YBa2Cu3O6.45 in magnetic fields up to 15 T. The field strongly enhances static incommensurate magnetic order at low temperatures and induces a spectral-weight shift in the magnetic-excitation spectrum. A reconstruction of the Fermi surface driven by the field-enhanced magnetic superstructure may thus be responsible for the unusual Fermi surface topology revealed by recent quantum-oscillation experiments.
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Affiliation(s)
- D Haug
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
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34
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Khasanov R, Evtushinsky DV, Amato A, Klauss HH, Luetkens H, Niedermayer C, Büchner B, Sun GL, Lin CT, Park JT, Inosov DS, Hinkov V. Two-gap superconductivity in Ba1-xKxFe2As2: a complementary study of the magnetic penetration depth by muon-spin rotation and angle-resolved photoemission. Phys Rev Lett 2009; 102:187005. [PMID: 19518904 DOI: 10.1103/physrevlett.102.187005] [Citation(s) in RCA: 3] [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: 01/15/2009] [Indexed: 05/27/2023]
Abstract
We investigate the magnetic penetration depth lambda in superconducting Ba1-xKxFe2As2 (Tc approximately 32 K) with muon-spin rotation (microSR) and angle-resolved photoemission (ARPES). Using microSR, we find the penetration-depth anisotropy gamma lambda=lambda c/lambda ab and the second-critical-field anisotropy gammaHc2 to show an opposite T evolution below Tc. This dichotomy resembles the situation in the two-gap superconductor MgB2. A two-gap scenario is also suggested by an inflection point in the in-plane penetration depth lambda ab around 7 K. The complementarity of microSR and ARPES allows us to pinpoint the values of the two gaps and to arrive to a remarkable agreement between the two techniques concerning the full T evolution of lambdaab. This provides further support for the described scenario and establishes ARPES as a tool to assess macroscopic properties of the superconducting condensate.
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Affiliation(s)
- R Khasanov
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
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35
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Koitzsch A, Inosov DS, Evtushinsky DV, Zabolotnyy VB, Kordyuk AA, Kondrat A, Hess C, Knupfer M, Büchner B, Sun GL, Hinkov V, Lin CT, Varykhalov A, Borisenko SV. Temperature and doping-dependent renormalization effects of the low energy electronic structure of Ba1-xKxFe2As2 single crystals. Phys Rev Lett 2009; 102:167001. [PMID: 19518744 DOI: 10.1103/physrevlett.102.167001] [Citation(s) in RCA: 3] [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: 11/03/2008] [Revised: 01/30/2009] [Indexed: 05/27/2023]
Abstract
We investigate the low energy electronic structure of Ba1-xKxFe2As2 (x=0; 0.3, T_{c}=32 K) single crystals by angle-resolved photoemission spectroscopy with a focus on the renormalization of the dispersion. A kink feature is detected at E approximately 25 meV for the doped compound which vanishes at T=200 K but stays virtually constant when T_{c} is crossed. Our experimental findings rule out the magnetic resonance mode as the origin of the kink and render conventional electron-phonon coupling unlikely. They put stringent restrictions on the dominant source of the electronic interaction channel.
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Affiliation(s)
- A Koitzsch
- Institute for Solid State Research, IFW-Dresden, P.O.Box 270116, D-01171 Dresden, Germany
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36
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Park JT, Inosov DS, Niedermayer C, Sun GL, Haug D, Christensen NB, Dinnebier R, Boris AV, Drew AJ, Schulz L, Shapoval T, Wolff U, Neu V, Yang X, Lin CT, Keimer B, Hinkov V. Electronic phase separation in the slightly underdoped iron pnictide superconductor Ba1-xKxFe2As2. Phys Rev Lett 2009; 102:117006. [PMID: 19392233 DOI: 10.1103/physrevlett.102.117006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Indexed: 05/27/2023]
Abstract
Here we present a combined study of the slightly underdoped novel pnictide superconductor Ba1-xKxFe2As2 by means of x-ray powder diffraction, neutron scattering, muon-spin rotation (microSR), and magnetic force microscopy (MFM). Static antiferromagnetic order sets in below T{m} approximately 70 K as inferred from the neutron scattering and zero-field-microSR data. Transverse-field microSR below Tc shows a coexistence of magnetically ordered and nonmagnetic states, which is also confirmed by MFM imaging. We explain such coexistence by electronic phase separation into antiferromagnetic and superconducting- or normal-state regions on a lateral scale of several tens of nanometers. Our findings indicate that such mesoscopic phase separation can be considered an intrinsic property of some iron pnictide superconductors.
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Affiliation(s)
- J T Park
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
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Zabolotnyy VB, Inosov DS, Evtushinsky DV, Koitzsch A, Kordyuk AA, Sun GL, Park JT, Haug D, Hinkov V, Boris AV, Lin CT, Knupfer M, Yaresko AN, Büchner B, Varykhalov A, Follath R, Borisenko SV. (pi, pi) electronic order in iron arsenide superconductors. Nature 2009; 457:569-72. [PMID: 19177126 DOI: 10.1038/nature07714] [Citation(s) in RCA: 177] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 12/02/2008] [Indexed: 11/09/2022]
Abstract
The distribution of valence electrons in metals usually follows the symmetry of the underlying ionic lattice. Modulations of this distribution often occur when those electrons are not stable with respect to a new electronic order, such as spin or charge density waves. Electron density waves have been observed in many families of superconductors, and are often considered to be essential for superconductivity to exist. Recent measurements seem to show that the properties of the iron pnictides are in good agreement with band structure calculations that do not include additional ordering, implying no relation between density waves and superconductivity in these materials. Here we report that the electronic structure of Ba(1-x)K(x)Fe(2)As(2) is in sharp disagreement with those band structure calculations, and instead reveals a reconstruction characterized by a (pi, pi) wavevector. This electronic order coexists with superconductivity and persists up to room temperature (300 K).
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Affiliation(s)
- V B Zabolotnyy
- Institute for Solid State Research, IFW-Dresden, PO Box 270116, 01171 Dresden, Germany
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38
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Bohnenbuck B, Zegkinoglou I, Strempfer J, Nelson CS, Wu HH, Schübler-Langeheine C, Reehuis M, Schierle E, Leininger P, Herrmannsdörfer T, Lang JC, Srajer G, Lin CT, Keimer B. Magnetic structure of RuSr2GdCu2O8 determined by resonant x-ray diffraction. Phys Rev Lett 2009; 102:037205. [PMID: 19257388 DOI: 10.1103/physrevlett.102.037205] [Citation(s) in RCA: 3] [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: 10/22/2008] [Indexed: 05/27/2023]
Abstract
X-ray diffraction with photon energies near the Ru L2-absorption edge was used to detect resonant reflections characteristic of a G-type superstructure in RuSr2GdCu2O8 single crystals. A polarization analysis confirms that these reflections are due to magnetic order of Ru moments, and the azimuthal-angle dependence of the scattering amplitude reveals that the moments lie along a low-symmetry axis with substantial components parallel and perpendicular to the RuO2 layers. Complemented by susceptibility data and a symmetry analysis of the magnetic structure, these results reconcile many of the apparently contradictory findings reported in the literature.
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Affiliation(s)
- B Bohnenbuck
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
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39
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Liang SF, Lin CT, Wu RC, Chen YC, Huang TY, Jung TP. Monitoring driver's alertness based on the driving performance estimation and the EEG power spectrum analysis. Conf Proc IEEE Eng Med Biol Soc 2008; 2005:5738-41. [PMID: 17281561 DOI: 10.1109/iembs.2005.1615791] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Preventing accidents caused by drowsiness behind the steering wheel is highly desirable but requires techniques for continuously estimating driver's abilities of perception, recognition and vehicle control abilities. This paper proposes methods for drowsiness estimation that combine the electroencephalogram (EEG) log subband power spectrum, correlation analysis, principal component analysis, and linear regression models to indirectly estimate driver's drowsiness level in a virtual-reality-based driving simulator. Results show that it is feasible to quantitatively monitor driver's alertness with concurrent changes in driving performance in a realistic driving simulator.
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Affiliation(s)
- S F Liang
- Brain Research Center, University System of Taiwan
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40
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Yu L, Munzar D, Boris AV, Yordanov P, Chaloupka J, Wolf T, Lin CT, Keimer B, Bernhard C. Evidence for two separate energy gaps in underdoped high-temperature cuprate superconductors from broadband infrared ellipsometry. Phys Rev Lett 2008; 100:177004. [PMID: 18518326 DOI: 10.1103/physrevlett.100.177004] [Citation(s) in RCA: 3] [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: 04/23/2007] [Indexed: 05/26/2023]
Abstract
We present broadband infrared ellipsometry measurements of the c-axis conductivity of underdoped RBa_{2}Cu_{3}O_{7-delta} (R=Y, Nd, and La) single crystals. Our data show that separate energy scales are underlying the redistributions of spectral weight due to the normal state pseudogap and the superconducting gap. Furthermore, they provide evidence that these gaps do not share the same electronic states and do not merge on the overdoped side. Accordingly, our data are suggestive of a two gap scenario with a pseudogap that is likely extrinsic with respect to superconductivity.
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Affiliation(s)
- Li Yu
- Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Chemin du Musee 3, CH-1700 Fribourg CH, Switzerland
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41
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Lin CT, Chen CR, Yang IH, Yin J, Han DJ. A controllable double-well magneto-optical trap for Rb and Cs atoms. Opt Express 2008; 16:6104-6111. [PMID: 18545311 DOI: 10.1364/oe.16.006104] [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: 05/26/2023]
Abstract
We experimentally demonstrate a novel scheme to simultaneously confine two atomic species of (87)Rb and (133)Cs with adjustable spatial separation by a controllable double-well magneto-optic trap. Using a single-loop wire and a magnetic bias field, the two clouds, each containing more than 1 x 10(6) atoms, are spatially separated above and below the wire center of the double-well MOT. The cloud interdistance can be controlled by independently varying the wire current and external bias field. This allows to load the double-well magnetic trap, and to study the dynamics of cold collisions between two-species atoms.
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Affiliation(s)
- C T Lin
- Department of Physics, National Chung Cheng University, Chia-Yi 621, Taiwan, R.O.C
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42
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Julien MH, de Vaulx C, Mayaffre H, Berthier C, Horvatić M, Simonet V, Wooldridge J, Balakrishnan G, Lees MR, Chen DP, Lin CT, Lejay P. Electronic texture of the thermoelectric oxide Na0.75CoO2. Phys Rev Lett 2008; 100:096405. [PMID: 18352735 DOI: 10.1103/physrevlett.100.096405] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Indexed: 05/26/2023]
Abstract
From 59Co and 23Na NMR, we demonstrate the impact of the Na+ vacancy ordering on the cobalt electronic states in Na0.75CoO2: at long time scales, there is neither a disproportionation into 75% Co3+ and 25% Co4+ states, nor a mixed-valence metal with a uniform Co3.25+ state. Instead, the system adopts an intermediate configuration in which 30% of the lattice sites form an ordered pattern of localized Co3+ states. Above 180 K, an anomalous mobility of specific Na+ sites is found to coexist with this electronic texture, suggesting that the formation of the latter may contribute to stabilizing the Na+ ordering. Control of the ion doping in these materials thus appears to be crucial for fine-tuning of their thermoelectric properties.
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Affiliation(s)
- M-H Julien
- Laboratoire de Spectrométrie Physique, UMR5588 CNRS, 38402 Saint Martin d'Hères, France.
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Abstract
This paper proposes a neuro-fuzzy combiner (NFC) with reinforcement learning capability for solving multiobjective control problems. The proposed NFC can combine n existing low-level controllers in a hierarchical way to form a multiobjective fuzzy controller. It is assumed that each low-level (fuzzy or nonfuzzy) controller has been well designed to serve a particular objective. The role of the NFC is to fuse the n actions decided by the n low-level controllers and determine a proper action acting on the environment (plant) at each time step. Hence, the NFC can combine low-level controllers and achieve multiple objectives (goals) at once. The NFC acts like a switch that chooses a proper action from the actions of low-level controllers according to the feedback information from the environment. In fact, the NFC is a soft switch; it allows more than one low-level actions to be active with different degrees through fuzzy combination at each time step. An NFC can be designed by the trial-and-error approach if enough a priori knowledge is available, or it can be obtained by supervised learning if precise input/output training data are available. In the more practical cases when there is no instructive teaching information available, the NFC can learn by itself using the proposed reinforcement learning scheme. Adopted with reinforcement learning capability, the NFC can learn to achieve desired multiobjectives simultaneously through the rough reinforcement feedback from the environment, which contains only critic information such as "success (good)" or "failure (bad)" for each desired objective. Computer simulations have been conducted to illustrate the performance and applicability of the proposed architecture and learning scheme.
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Affiliation(s)
- C T Lin
- Dept. of Electr. & Control Eng., Nat. Chiao Tung Univ., Hsinchu
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44
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Liang SF, Su AY, Lin CT. Model-based synthesis of plucked string instruments by using a class of scattering recurrent networks. IEEE Trans Neural Netw 2008; 11:171-85. [PMID: 18249748 DOI: 10.1109/72.822519] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A physical modeling method for electronic music synthesis of plucked-string tones by using recurrent networks is proposed. A scattering recurrent network (SRN) which is used to analyze string dynamics is built based on the physics of acoustic strings. The measured vibration of a plucked string is employed as the training data for the supervised learning of the SRN. After the network is well trained, it can be regarded as the virtual model for the measured string and used to generate tones which can be very close to those generated by its acoustic counterpart. The "virtual string" corresponding to the SRN can respond to different "plucks" just like a real string, which is impossible using traditional synthesis techniques such as frequency modulation and wavetable. The simulation of modeling a cello "A"-string demonstrates some encouraging results of the new music synthesis technique. Some aspects of modeling and synthesis procedures are also discussed.
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Affiliation(s)
- S F Liang
- Department of Electrical and Control Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan, R.O.C
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45
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Wang CH, Liu HL, Lin CT. Dynamic optimal learning rates of a certain class of fuzzy neural networks and its applications with genetic algorithm. ACTA ACUST UNITED AC 2008; 31:467-75. [PMID: 18244813 DOI: 10.1109/3477.931548] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The stability analysis of the learning rate for a two-layer neural network (NN) is discussed first by minimizing the total squared error between the actual and desired outputs for a set of training vectors. The stable and optimal learning rate, in the sense of maximum error reduction, for each iteration in the training (back propagation) process can therefore be found for this two-layer NN. It has also been proven in this paper that the dynamic stable learning rate for this two-layer NN must be greater than zero. Thus it Is guaranteed that the maximum error reduction can be achieved by choosing the optimal learning rate for the next training iteration. A dynamic fuzzy neural network (FNN) that consists of the fuzzy linguistic process as the premise part and the two-layer NN as the consequence part is then illustrated as an immediate application of our approach. Each part of this dynamic FNN has its own learning rate for training purpose. A genetic algorithm is designed to allow a more efficient tuning process of the two learning rates of the FNN. The objective of the genetic algorithm is to reduce the searching time by searching for only one learning rate, which is the learning rate of the premise part, in the FNN. The dynamic optimal learning rates of the two-layer NN can be found directly using our innovative approach. Several examples are fully illustrated and excellent results are obtained for the model car backing up problem and the identification of nonlinear first order and second order systems.
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Affiliation(s)
- C H Wang
- Sch. of Microelectron. Eng., Griffith Univ., Brisbane, Qld
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46
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Hinkov V, Haug D, Fauqué B, Bourges P, Sidis Y, Ivanov A, Bernhard C, Lin CT, Keimer B. Electronic liquid crystal state in the high-temperature superconductor YBa2Cu3O6.45. Science 2008; 319:597-600. [PMID: 18187621 DOI: 10.1126/science.1152309] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Electronic phases with symmetry properties matching those of conventional liquid crystals have recently been discovered in transport experiments on semiconductor heterostructures and metal oxides at millikelvin temperatures. We report the spontaneous onset of a one-dimensional, incommensurate modulation of the spin system in the high-transition-temperature superconductor YBa2Cu3O6.45 upon cooling below approximately 150 kelvin, whereas static magnetic order is absent above 2 kelvin. The evolution of this modulation with temperature and doping parallels that of the in-plane anisotropy of the resistivity, indicating an electronic nematic phase that is stable over a wide temperature range. The results suggest that soft spin fluctuations are a microscopic route toward electronic liquid crystals and that nematic order can coexist with high-temperature superconductivity in underdoped cuprates.
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Affiliation(s)
- V Hinkov
- Max-Planck-Institut für Festkörperforschung, Heisenberg-strasse 1, D-70569 Stuttgart, Germany.
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47
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Peng PC, Lin CT, Kuo HC, Tsai WK, Liu JN, Chi S, Wang SC, Lin G, Yang HP, Lin KF, Chi JY. Tunable slow light device using quantum dot semiconductor laser. Opt Express 2006; 14:12880-12886. [PMID: 19532181 DOI: 10.1364/oe.14.012880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This investigation experimentally demonstrates a tunable slow light device using a quantum dot (QD) semiconductor laser. The QD semiconductor laser at 1.3 mum fabricated on a GaAs substrate is grown by molecular beam epitaxy. Tunable slow light can be achieved by adjusting the bias current and wavelength detuning. The slow light device operated under probe signal from 5 to 10 GHz is presented. Moreover, we also demonstrate that the tunable slow light device can be used in a subcarrier multiplexed system.
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48
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Kordyuk AA, Borisenko SV, Zabolotnyy VB, Geck J, Knupfer M, Fink J, Büchner B, Lin CT, Keimer B, Berger H, Pan AV, Komiya S, Ando Y. Constituents of the quasiparticle spectrum along the nodal direction of high-Tc cuprates. Phys Rev Lett 2006; 97:017002. [PMID: 16907398 DOI: 10.1103/physrevlett.97.017002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Indexed: 05/11/2023]
Abstract
Applying the Kramers-Kronig consistent procedure, developed earlier, we investigate in detail the formation of the quasiparticle spectrum along the nodal direction of high-Tc cuprates. The heavily discussed "70 meV kink" on the renormalized dispersion exhibits a strong temperature and doping dependence when purified from structural effects such as bilayer splitting, diffraction replicas, etc. This dependence is well understood in terms of fermionic and bosonic constituents of the self-energy. The latter follows the evolution of the spin-fluctuation spectrum, emerging below some doping dependent temperature and sharpening below Tc, and is mainly responsible for the formation of the kink in question.
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Affiliation(s)
- A A Kordyuk
- Institut für Festkoerper und Werkstofforschung Dresden, Post Office Box 270116, D-01171 Dresden, Germany
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49
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Pailhès S, Ulrich C, Fauqué B, Hinkov V, Sidis Y, Ivanov A, Lin CT, Keimer B, Bourges P. Doping dependence of bilayer resonant spin excitations in (Y, Ca)Ba2Cu3O6+x. Phys Rev Lett 2006; 96:257001. [PMID: 16907334 DOI: 10.1103/physrevlett.96.257001] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Indexed: 05/11/2023]
Abstract
Resonant magnetic modes with odd and even symmetries were studied by inelastic neutron scattering experiments in the bilayer high-Tc superconductor Y1-xCa+Ba2Cu3O6+y over a wide doping range. The threshold of the spin excitation continuum in the superconducting state, deduced from the energies and spectral weights of both modes, is compared with the superconducting d-wave gap, deduced from electronic Raman scattering in the B1g symmetry on the same samples. Above a critical doping level of delta approximately =0.19, both mode energies and the continuum threshold coincide. We find a simple scaling relationship between the characteristic energies and spectral weights of both modes, which indicates that the resonant modes are bound states in the superconducting energy gap, as predicted by the spin-exciton model of the resonant mode.
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Affiliation(s)
- S Pailhès
- Laboratoire Léon Brillouin, CEA-CNRS, CE-Saclay, 91191 Gif sur Yvette, France
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50
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Fauqué B, Sidis Y, Hinkov V, Pailhès S, Lin CT, Chaud X, Bourges P. Magnetic order in the pseudogap phase of high-Tc superconductors. Phys Rev Lett 2006; 96:197001. [PMID: 16803131 DOI: 10.1103/physrevlett.96.197001] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Indexed: 05/10/2023]
Abstract
One of the leading issues in high-T(c) superconductors is the origin of the pseudogap phase in underdoped cuprates. Using polarized elastic neutron diffraction, we identify a novel magnetic order in the YB(2)Cu(3)O(6+) system. The observed magnetic order preserves translational symmetry of the lattice as proposed for orbital moments in the circulating current theory of the pseudogap state. To date, it is the first direct evidence of a hidden order parameter characterizing the pseudogap phase in high-T(c) cuprates.
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Affiliation(s)
- B Fauqué
- Laboratoire Léon Brillouin, CEA-CNRS, CEA-Saclay, Gif sur Yvette, France
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