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Jang MH, Kim TK, Park JW, Kim TH, Hwang YS, Kim SO. Elucidating adsorption mechanisms of benzalkonium chlorides (BACs) on polypropylene and polyethylene terephthalate microplastics (MPs): Effects of BACs alkyl chain length and MPs characteristics. J Hazard Mater 2024; 468:133765. [PMID: 38387174 DOI: 10.1016/j.jhazmat.2024.133765] [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] [Received: 11/21/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 02/24/2024]
Abstract
Since the onset of the COVID-19 pandemic, there has been an increase in the use of disposable plastics and disinfectants. This study systematically investigated the adsorption behavior and mechanisms of benzalkonium chlorides (BACs), commonly used disinfectants, on polypropylene (PP) and polyethylene terephthalate (PET) microplastics (MPs), considering various factors, such as characteristics of MPs, alkyl chain length of BACs, and environmental conditions. Our results demonstrated a higher adsorption capacity for PP-MPs with relatively hydrophobic properties compared to PET-MPs, where longer alkyl chains in BACs (i.e., higher octanol-water partition coefficients, Kow) significantly enhanced adsorption through hydrophobic interactions. The inverse relationship between particle size of MPs and adsorption was evident. While changes in pH minimally affected adsorption on PP-MPs, adsorption on PET-MPs increased with rising pH, highlighting the influence of pH on electrostatic interactions. Moreover, MP aging with UV/H2O2 amplified BAC adsorption on PP-MPs due to surface oxidation and fragmentation, whereas the properties of PET-MPs remained unaltered, resulting in unchanged adsorption capacities. Spectroscopy studies and density functional theory (DFT) calculations confirmed hydrophobic and electrostatic interactions as the primary adsorption mechanisms. These findings improve our understanding of MPs and BACs behavior in the environment, providing insights for environmental risk assessments related to combined pollution.
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Affiliation(s)
- Min-Hee Jang
- Environmental Exposure & Toxicology Research Center, Korea Institute of Toxicology, Jinju 52834, Republic of Korea; Department of Geology and Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Tae-Kyoung Kim
- Department of Civil and Environmental Engineering, University of California at Berkeley, Berkeley, CA 94720, USA
| | - June-Woo Park
- Environmental Exposure & Toxicology Research Center, Korea Institute of Toxicology, Jinju 52834, Republic of Korea
| | - Tae Hee Kim
- Advanced Textile R&D Department, Korea Institute of Industrial Technology, Ansan 15588, Republic of Korea
| | - Yu Sik Hwang
- Environmental Exposure & Toxicology Research Center, Korea Institute of Toxicology, Jinju 52834, Republic of Korea.
| | - Soon-Oh Kim
- Department of Geology and Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea.
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2
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Hunter A, Beck S, Cappelli E, Margot F, Straub M, Alexanian Y, Gatti G, Watson MD, Kim TK, Cacho C, Plumb NC, Shi M, Radović M, Sokolov DA, Mackenzie AP, Zingl M, Mravlje J, Georges A, Baumberger F, Tamai A. Fate of Quasiparticles at High Temperature in the Correlated Metal Sr_{2}RuO_{4}. Phys Rev Lett 2023; 131:236502. [PMID: 38134803 DOI: 10.1103/physrevlett.131.236502] [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: 08/04/2023] [Accepted: 11/08/2023] [Indexed: 12/24/2023]
Abstract
We study the temperature evolution of quasiparticles in the correlated metal Sr_{2}RuO_{4}. Our angle resolved photoemission data show that quasiparticles persist up to temperatures above 200 K, far beyond the Fermi liquid regime. Extracting the quasiparticle self-energy, we demonstrate that the quasiparticle residue Z increases with increasing temperature. Quasiparticles eventually disappear on approaching the bad metal state of Sr_{2}RuO_{4} not by losing weight but via excessive broadening from super-Planckian scattering. We further show that the Fermi surface of Sr_{2}RuO_{4}-defined as the loci where the spectral function peaks-deflates with increasing temperature. These findings are in semiquantitative agreement with dynamical mean field theory calculations.
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Affiliation(s)
- A Hunter
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - S Beck
- Center for Computational Quantum Physics, Flatiron Institute, 162 Fifth Avenue, New York, New York 10010, USA
| | - E Cappelli
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - F Margot
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - M Straub
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Y Alexanian
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - G Gatti
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - M D Watson
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - C Cacho
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - N C Plumb
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Shi
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Radović
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - D A Sokolov
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - A P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - M Zingl
- Center for Computational Quantum Physics, Flatiron Institute, 162 Fifth Avenue, New York, New York 10010, USA
| | - J Mravlje
- Department of Theoretical Physics, Institute Jozef Stefan, Jamova 39, SI-1001 Ljubljana, Slovenia
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana
| | - A Georges
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
- Center for Computational Quantum Physics, Flatiron Institute, 162 Fifth Avenue, New York, New York 10010, USA
- Collège de France, 11 Place Marcelin Berthelot, 75005 Paris, France
- Centre de Physique Théorique, Ecole Polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
| | - F Baumberger
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Tamai
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
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Honma A, Takane D, Souma S, Yamauchi K, Wang Y, Nakayama K, Sugawara K, Kitamura M, Horiba K, Kumigashira H, Tanaka K, Kim TK, Cacho C, Oguchi T, Takahashi T, Ando Y, Sato T. Antiferromagnetic topological insulator with selectively gapped Dirac cones. Nat Commun 2023; 14:7396. [PMID: 37978297 PMCID: PMC10656484 DOI: 10.1038/s41467-023-42782-6] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 10/20/2023] [Indexed: 11/19/2023] Open
Abstract
Antiferromagnetic (AF) topological materials offer a fertile ground to explore a variety of quantum phenomena such as axion magnetoelectric dynamics and chiral Majorana fermions. To realize such intriguing states, it is essential to establish a direct link between electronic states and topology in the AF phase, whereas this has been challenging because of the lack of a suitable materials platform. Here we report the experimental realization of the AF topological-insulator phase in NdBi. By using micro-focused angle-resolved photoemission spectroscopy, we discovered contrasting surface electronic states for two types of AF domains; the surface having the out-of-plane component in the AF-ordering vector displays Dirac-cone states with a gigantic energy gap, whereas the surface parallel to the AF-ordering vector hosts gapless Dirac states despite the time-reversal-symmetry breaking. The present results establish an essential role of combined symmetry to protect massless Dirac fermions under the presence of AF order and widen opportunities to realize exotic phenomena utilizing AF topological materials.
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Affiliation(s)
- A Honma
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
| | - D Takane
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
| | - S Souma
- Center for Science and Innovation in Spintronics (CSIS), Tohoku University, Sendai, 980-8577, Japan.
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, 980-8577, Japan.
| | - K Yamauchi
- Center for Spintronics Research Network (CSRN), Osaka University, Toyonaka, Osaka, 560-8531, Japan
| | - Y Wang
- Institute of Physics II, University of Cologne, Köln, 50937, Germany
| | - K Nakayama
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Tokyo, 102-0076, Japan
| | - K Sugawara
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, 980-8577, Japan
| | - M Kitamura
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, 305-0801, Japan
- National Institutes for Quantum Science and Technology (QST), Sendai, 980-8579, Japan
| | - K Horiba
- National Institutes for Quantum Science and Technology (QST), Sendai, 980-8579, Japan
| | - H Kumigashira
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Sendai, 980-8577, Japan
| | - K Tanaka
- UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki, 444-8585, Japan
| | - T K Kim
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | - C Cacho
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0QX, UK
| | - T Oguchi
- Center for Spintronics Research Network (CSRN), Osaka University, Toyonaka, Osaka, 560-8531, Japan
| | - T Takahashi
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, 980-8577, Japan
| | - Yoichi Ando
- Institute of Physics II, University of Cologne, Köln, 50937, Germany
| | - T Sato
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan.
- Center for Science and Innovation in Spintronics (CSIS), Tohoku University, Sendai, 980-8577, Japan.
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, 980-8577, Japan.
- International Center for Synchrotron Radiation Innov1ation Smart (SRIS), Tohoku University, Sendai, 980-8577, Japan.
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Kim TK, Sedlak DL. Mineralization of a Fully Halogenated Organic Compound by Persulfate under Conditions Relevant to in Situ Reduction and Oxidation: Reduction of Hexachloroethane by Ethanol Addition Followed by Oxidation. Environ Sci Technol 2023; 57:13691-13698. [PMID: 37640476 PMCID: PMC10501115 DOI: 10.1021/acs.est.3c03489] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 08/31/2023]
Abstract
Fully halogenated compounds are difficult to remediate by in situ chemical oxidation (ISCO) because carbon-halogen bonds react very slowly with the species that typically initiate contaminant transformation: sulfate radical (SO4•-) and hydroxyl radical (•OH). To enable the remediation of this class of contaminants by persulfate (S2O82-)-based ISCO, we employed a two-phase process to dehalogenate and oxidize a representative halogenated compound (i.e., hexachloroethane). In the first phase, a relatively high concentration of ethanol (1.8 M) was added, along with concentrations of S2O82- that are typically used for ISCO (i.e., 450 mM). Hexachloroethane underwent rapid dehalogenation when carbon-centered radicals produced by the reaction of ethanol and radicals formed during S2O82- decomposition reacted with carbon-halogen bonds. Unlike conventional ISCO treatment, hexachloroethane transformation and S2O82- decomposition took place on the time scale of days without external heating or base addition. The presence of O2, Cl-, and NO3- delayed the onset of hexachloroethane transformation when low concentrations of S2O82- (10 mM) were used, but these solutes had negligible effects when S2O82- was present at concentrations typical of in situ remediation (450 mM). The second phase of the reaction was initiated after most of the ethanol had been depleted when thermolytic S2O82- decomposition resulted in production of SO4•- that oxidized the partially dehalogenated transformation products. With proper precautions, S2O82--based ISCO with ethanol could be a useful remediation technology for sites contaminated with fully halogenated compounds.
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Affiliation(s)
- Tae-Kyoung Kim
- Department of Civil and Environmental
Engineering University of California, Berkeley, California 94720, United States
| | - David L. Sedlak
- Department of Civil and Environmental
Engineering University of California, Berkeley, California 94720, United States
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Kang D, Lee ES, Kim TK, Kim YJ, Lee S, Lee W, Sim H, Kim SY. Association with Combined Occupational Hazards Exposure and Risk of Metabolic Syndrome: A Workers' Health Examination Cohort 2012-2021. Saf Health Work 2023; 14:279-286. [PMID: 37822462 PMCID: PMC10562170 DOI: 10.1016/j.shaw.2023.08.006] [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: 04/06/2023] [Revised: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 10/13/2023] Open
Abstract
Background This study aimed to evaluate the association between exposure to occupational hazards and the metabolic syndrome. A secondary objective was to analyze the additive and multiplicative effects of exposure to risk factors. Methods This retrospective cohort was based on 31,615 health examinees at the Pusan National University Yangsan Hospital in Republic of Korea from 2012-2021. Demographic and behavior-related risk factors were treated as confounding factors, whereas three physical factors, 19 organic solvents and aerosols, and 13 metals and dust were considered occupational risk factors. Time-dependent Cox regression analysis was used to calculate hazard ratios. Results The risk of metabolic syndrome was significantly higher in night shift workers (hazard ratio = 1.45: 95% confidence interval = 1.36-1.54) and workers who were exposed to noise (1.15:1.07-1.24). Exposure to some other risk factors was also significantly associated with a higher risk of metabolic syndrome. They were dimethylformamide, acetonitrile, trichloroethylene, xylene, styrene, toluene, dichloromethane, copper, antimony, lead, copper, iron, welding fume, and manganese. Among the 28 significant pairs, 19 exhibited both positive additive and multiplicative effects. Conclusions Exposure to single or combined occupational risk factors may increase the risk of developing metabolic syndrome. Working conditions should be monitored and improved to reduce exposure to occupational hazards and prevent the development of the metabolic syndrome.
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Affiliation(s)
- Dongmug Kang
- Department of Preventive, and Occupational & Environmental Medicine, School of Medicine, Pusan National University, Republic of Korea
- Department of Occupational and Environmental Medicine, Pusan National University Yangsan Hospital, Republic of Korea
| | - Eun-Soo Lee
- Department of Occupational and Environmental Medicine, Pusan National University Yangsan Hospital, Republic of Korea
| | - Tae-Kyoung Kim
- Medical Research Institute, Pusan National University, Republic of Korea
| | - Yoon-Ji Kim
- Department of Preventive, and Occupational & Environmental Medicine, School of Medicine, Pusan National University, Republic of Korea
| | - Seungho Lee
- Department of Occupational and Environmental Medicine, Pusan National University Yangsan Hospital, Republic of Korea
| | - Woojoo Lee
- Department of Public Health Science, Graduate School of Public Health, Seoul National, Republic of Korea
| | - Hyunman Sim
- Department of Public Health Science, Graduate School of Public Health, Seoul National, Republic of Korea
| | - Se-Yeong Kim
- Department of Preventive, and Occupational & Environmental Medicine, School of Medicine, Pusan National University, Republic of Korea
- Department of Occupational and Environmental Medicine, Pusan National University Yangsan Hospital, Republic of Korea
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6
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Gatti G, Issing J, Rademaker L, Margot F, de Jong TA, van der Molen SJ, Teyssier J, Kim TK, Watson MD, Cacho C, Dudin P, Avila J, Edwards KC, Paruch P, Ubrig N, Gutiérrez-Lezama I, Morpurgo AF, Tamai A, Baumberger F. Flat Γ Moiré Bands in Twisted Bilayer WSe_{2}. Phys Rev Lett 2023; 131:046401. [PMID: 37566843 DOI: 10.1103/physrevlett.131.046401] [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: 11/25/2022] [Accepted: 06/26/2023] [Indexed: 08/13/2023]
Abstract
The recent observation of correlated phases in transition metal dichalcogenide moiré systems at integer and fractional filling promises new insight into metal-insulator transitions and the unusual states of matter that can emerge near such transitions. Here, we combine real- and momentum-space mapping techniques to study moiré superlattice effects in 57.4° twisted WSe_{2} (tWSe_{2}). Our data reveal a split-off flat band that derives from the monolayer Γ states. Using advanced data analysis, we directly quantify the moiré potential from our data. We further demonstrate that the global valence band maximum in tWSe_{2} is close in energy to this flat band but derives from the monolayer K states which show weaker superlattice effects. These results constrain theoretical models and open the perspective that Γ-valley flat bands might be involved in the correlated physics of twisted WSe_{2}.
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Affiliation(s)
- G Gatti
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - J Issing
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - L Rademaker
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
- Department of Theoretical Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - F Margot
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - T A de Jong
- Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, Leiden, The Netherlands
| | - S J van der Molen
- Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, Leiden, The Netherlands
| | - J Teyssier
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - M D Watson
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - C Cacho
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - P Dudin
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin-BP 48, 91192 Gif sur Yvette Cedex, France
| | - J Avila
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin-BP 48, 91192 Gif sur Yvette Cedex, France
| | - K Cordero Edwards
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - P Paruch
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - N Ubrig
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
- Department of Applied Physics, University of Geneva, 24 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - I Gutiérrez-Lezama
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
- Department of Applied Physics, University of Geneva, 24 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - A F Morpurgo
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
- Department of Applied Physics, University of Geneva, 24 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - A Tamai
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
| | - F Baumberger
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva, Switzerland
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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Han S, Kye H, Kim CS, Kim TK, Yoo J, Kim J. Automated Laser-Fiber Coupling Module for Optical-Resolution Photoacoustic Microscopy. Sensors (Basel) 2023; 23:6643. [PMID: 37514935 PMCID: PMC10384817 DOI: 10.3390/s23146643] [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: 06/13/2023] [Revised: 07/11/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023]
Abstract
Photoacoustic imaging has emerged as a promising biomedical imaging technique that enables visualization of the optical absorption characteristics of biological tissues in vivo. Among the different photoacoustic imaging system configurations, optical-resolution photoacoustic microscopy stands out by providing high spatial resolution using a tightly focused laser beam, which is typically transmitted through optical fibers. Achieving high-quality images depends significantly on optical fluence, which is directly proportional to the signal-to-noise ratio. Hence, optimizing the laser-fiber coupling is critical. Conventional coupling systems require manual adjustment of the optical path to direct the laser beam into the fiber, which is a repetitive and time-consuming process. In this study, we propose an automated laser-fiber coupling module that optimizes laser delivery and minimizes the need for manual intervention. By incorporating a motor-mounted mirror holder and proportional derivative control, we successfully achieved efficient and robust laser delivery. The performance of the proposed system was evaluated using a leaf-skeleton phantom in vitro and a human finger in vivo, resulting in high-quality photoacoustic images. This innovation has the potential to significantly enhance the quality and efficiency of optical-resolution photoacoustic microscopy.
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Affiliation(s)
- Seongyi Han
- Departments of Cogno-Mechatronics Engineering and Optics & Mechatronics Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Hyunjun Kye
- Departments of Cogno-Mechatronics Engineering and Optics & Mechatronics Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Chang-Seok Kim
- Departments of Cogno-Mechatronics Engineering and Optics & Mechatronics Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Tae-Kyoung Kim
- Department of Electronic Engineering, Gachon University, Seongnam 13120, Republic of Korea
| | - Jinwoo Yoo
- Department of Automobile and IT Convergence, Kookmin University, Seoul 02707, Republic of Korea
| | - Jeesu Kim
- Departments of Cogno-Mechatronics Engineering and Optics & Mechatronics Engineering, Pusan National University, Busan 46241, Republic of Korea
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Min M, Kong JI, Kim TK. Non-Orthogonal Multiple Access with One-Bit Analog-to-Digital Converters Using Threshold Adaptation. Sensors (Basel) 2023; 23:6004. [PMID: 37447853 DOI: 10.3390/s23136004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/21/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023]
Abstract
In digital communication systems featuring high-resolution analog-to-digital converters (ADCs), the utilization of successive interference cancellation and detection can enhance the capacity of a Gaussian multiple access channel (MAC) by combining signals from multiple transmitters in a non-orthogonal manner. Conversely, in systems employing one-bit ADCs, it is exceedingly difficult to eliminate non-orthogonal interference using digital signal processing due to the considerable distortion present in the received signal when employing such ADCs. As a result, the Gaussian MAC does not yield significant capacity gains in such cases. To address this issue, we demonstrate that, under a given deterministic interference, the capacity of a one-bit-quantized channel becomes equivalent to the capacity without interference when an appropriate threshold value is chosen. This finding suggests the potential for indirect interference cancellation in the analog domain, facilitating the proposition of an efficient successive interference cancellation and detection scheme. We analyze the achievable rate of the proposed scheme by deriving the mutual information between the transmitted and received signals at each detection stage. The obtained results indicate that the sum rate of the proposed scheme generally outperforms conventional methods, with the achievable upper bound being twice as high as that of the conventional methods. Additionally, we have developed an optimal transmit power allocation algorithm to maximize the sum rate in fading channels.
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Affiliation(s)
- Moonsik Min
- School of Electronics Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
- School of Electronic and Electrical Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Jae-Ik Kong
- School of Electronic and Electrical Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Tae-Kyoung Kim
- Department of Electronic Engineering, Gachon University, Seongnam 13120, Republic of Korea
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9
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Kim TK, Min M. Reinforcement Learning-Aided Channel Estimator in Time-Varying MIMO Systems. Sensors (Basel) 2023; 23:5689. [PMID: 37420854 DOI: 10.3390/s23125689] [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: 04/17/2023] [Revised: 06/08/2023] [Accepted: 06/16/2023] [Indexed: 07/09/2023]
Abstract
This paper proposes a reinforcement learning-aided channel estimator for time-varying multi-input multi-output systems. The basic concept of the proposed channel estimator is the selection of the detected data symbol in the data-aided channel estimation. To achieve the selection successfully, we first formulate an optimization problem to minimize the data-aided channel estimation error. However, in time-varying channels, the optimal solution is difficult to derive because of its computational complexity and the time-varying nature of the channel. To address these difficulties, we consider a sequential selection for the detected symbols and a refinement for the selected symbols. A Markov decision process is formulated for sequential selection, and a reinforcement learning algorithm that efficiently computes the optimal policy is proposed with state element refinement. Simulation results demonstrate that the proposed channel estimator outperforms conventional channel estimators by efficiently capturing the variation of the channels.
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Affiliation(s)
- Tae-Kyoung Kim
- Department of Electronic Engineering, Gachon University, Seongnam 13120, Republic of Korea
| | - Moonsik Min
- School of Electronic and Electrical Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
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Kim TK. Improved Likelihood Probability in MIMO Systems Using One-Bit ADCs. Sensors (Basel) 2023; 23:5542. [PMID: 37420711 DOI: 10.3390/s23125542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/05/2023] [Accepted: 06/12/2023] [Indexed: 07/09/2023]
Abstract
This study considers an improved likelihood probability in multi-input multi-output (MIMO) systems using one-bit analog-to-digital converters (ADCs). MIMO systems using one-bit ADCs are known to exhibit from performance degradation because of inaccurate likelihood probabilities. To overcome this degradation, the proposed method leverages the detected symbols to estimate the true likelihood probability by combining the initial likelihood probability. An optimization problem is formulated to minimize the mean-squared error between the true and combined likelihood probabilities, and a solution is derived using the least-squares method. Simulation results show that the proposed method obtains a signal-to-noise gain of approximately 0.3 dB to achieve a frame error rate of 10-1 compared to conventional methods. This improvement in performance is attributed to the enhanced reliability of the likelihood probability.
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Affiliation(s)
- Tae-Kyoung Kim
- Department of Electronic Engineering, Gachon University, Seongnam 13120, Republic of Korea
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11
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Park S, Kim J, Jeong HY, Kim TK, Yoo J. C2RL: Convolutional-Contrastive Learning for Reinforcement Learning Based on Self-Pretraining for Strong Augmentation. Sensors (Basel) 2023; 23:4946. [PMID: 37430860 DOI: 10.3390/s23104946] [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: 04/18/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 07/12/2023]
Abstract
Reinforcement learning agents that have not been seen during training must be robust in test environments. However, the generalization problem is challenging to solve in reinforcement learning using high-dimensional images as the input. The addition of a self-supervised learning framework with data augmentation in the reinforcement learning architecture can promote generalization to a certain extent. However, excessively large changes in the input images may disturb reinforcement learning. Therefore, we propose a contrastive learning method that can help manage the trade-off relationship between the performance of reinforcement learning and auxiliary tasks against the data augmentation strength. In this framework, strong augmentation does not disturb reinforcement learning and instead maximizes the auxiliary effect for generalization. Results of experiments on the DeepMind Control suite demonstrate that the proposed method effectively uses strong data augmentation and achieves a higher generalization than the existing methods.
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Affiliation(s)
- Sanghoon Park
- Graduate School of Automotive Engineering, Kookmin University, Seoul 02707, Republic of Korea
| | - Jihun Kim
- Graduate School of Automotive Engineering, Kookmin University, Seoul 02707, Republic of Korea
| | - Han-You Jeong
- Department of Electrical Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Tae-Kyoung Kim
- Department of Electronic Engineering, Gachon University, Seongnam 13120, Republic of Korea
| | - Jinwoo Yoo
- Department of Automobile and IT Convergence, Kookmin University, Seoul 02707, Republic of Korea
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12
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Jung S, Kim TK, Kim YJ, Kim YK, Kang D, Kim SY. Epidemiology of occupational injuries in construction workers between 2009 and 2018 in South Korea. Am J Ind Med 2023; 66:155-166. [PMID: 36433706 PMCID: PMC10100143 DOI: 10.1002/ajim.23448] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [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: 08/23/2022] [Revised: 11/17/2022] [Accepted: 11/17/2022] [Indexed: 11/27/2022]
Abstract
BACKGROUND This study aimed to investigate the characteristics of occupational injuries based on fatality, sex, and classification of occupations among construction workers using workers' compensation (WC) insurance data in South Korea. METHODS We collected WC insurance data from the Korea Workers' Compensation & Welfare Service for all construction workers between 2009 and 2018. Data from 158,947 accepted claims for occupational injury were extracted, and the demographic features, occupational injury types, and annual trends were analyzed for fatal and nonfatal cases. The annual incidence and mortality trends of occupational injury were estimated using negative binomial regression and Poisson regression models, for injury incidence and mortality respectively. RESULTS Among a total of 158,947 occupational injury cases, there were 155,772 (98%) nonfatal injuries and 3175 (2%) fatal injuries. For all occupational injuries, Construction Elementary Workers (6th Korean Standard Classification of Occupations (KSCO) 910; 45.7%) was the most frequent occupation, followed by Construction-Related Technical Workers (6th KSCO 772; 39.2%). The most frequent injury type was a fracture, followed by ruptures or lacerations and contusions. The incidence of all occupational injuries increased from 700.36 per 100,000 persons in 2009 to 1,195.98 per 100,000 persons in 2018. Further, deaths from injuries at work followed a significantly increasing annual trend [mortality rate ratio 1.04 (95% CI: 1.03-1.05)] from 2009 to 2018. CONCLUSION The over two-thirds increased incidence of occupational injuries and significantly increasing mortality trends for occupational injuries during the last 10 years indicate the need for aggressive intervention in occupational safety and health management within the Korean construction industry.
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Affiliation(s)
- Saemi Jung
- Department of Occupational and Environmental Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Tae-Kyoung Kim
- Medical Research Institute, Pusan National University, Yangsan, Republic of Korea
| | - Yoon-Ji Kim
- Department of Preventive and Occupational & Environmental Medicine, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Young-Ki Kim
- Department of Occupational and Environmental Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.,Department of Preventive and Occupational & Environmental Medicine, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Dongmug Kang
- Department of Occupational and Environmental Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.,Department of Preventive and Occupational & Environmental Medicine, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Se-Yeong Kim
- Department of Occupational and Environmental Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.,Department of Preventive and Occupational & Environmental Medicine, School of Medicine, Pusan National University, Yangsan, Republic of Korea
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13
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Lee S, Kim HJ, Kim JH, Kim TK, Kang CN, Lee JH, Cho JH, Kim SH, Moon SH. Evaluation of the efficacy and safety of NVP-1203 and aceclofenac in patients with acute low back pain and muscle spasm: A randomized, double-blind, active-controlled, parallel, multicenter, phase 3 clinical trial. Eur Rev Med Pharmacol Sci 2023; 27:315-324. [PMID: 36647880 DOI: 10.26355/eurrev_202301_30878] [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: 01/18/2023]
Abstract
OBJECTIVE Acute low back pain (LBP) is a common condition that can be chronic if not properly treated. Aceclofenac and eperisone hydrochloride are commonly prescribed drugs for acute LBP and muscle spasms. Therefore, NVP-1203, a fixed-dose combination of 100 mg aceclofenac and 75 mg eperisone hydrochloride, is being developed. This study aimed to evaluate the efficacy and safety of NVP-1203 compared to those of a single administration of 100 mg aceclofenac in patients with acute LBP and muscle spasms. PATIENTS AND METHODS Overall, 455 patients with acute LBP and muscle spasms were enrolled. The patients were assigned to NVP-1203 or Airtal group (aceclofenac 100 mg). The primary efficacy endpoint was the mean change in the 100 mm pain movement and resting visual analog scale (VAS) scores on treatment day 7. RESULTS The mean change in the 100 mm pain movement/resting VAS scores from baseline to day 7 was -49.7 ± 21.5/-41.0 ± 19.4 mm and -38.8 ± 18.9/-33.8 ± 18.0 mm for the NVP-1203 and Airtal groups, respectively. The differences between the two groups were statistically significant (movement, p < 0.0001; resting, p = 0.0002). Differences in least-square (LS) mean change of the 100 mm pain movement/resting VAS score between the two groups using the analysis of covariance (ANCOVA) model was -10.2/-7.4 mm, and the upper limit of the 95% confidence interval was -6.44/-4.16 mm. CONCLUSIONS NVP-1203 is more effective in reducing pain than the 100 mg aceclofenac alone. However, the two drugs have similar safety profiles in patients with acute LBP and muscle spasms.
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Affiliation(s)
- S Lee
- Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Gyeonggi-do, Republic of Korea.
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14
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Kim TK. Cooperative DF Protocol for MIMO Systems Using One-Bit ADCs. Sensors (Basel) 2022; 22:7843. [PMID: 36298194 PMCID: PMC9608961 DOI: 10.3390/s22207843] [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] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/07/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
This study considers a detection scheme for cooperative multi-input-multi-output (MIMO) systems using one-bit analog-to-digital converters (ADCs) in a decode-and-forward (DF) relay protocol. The use of one-bit ADCs is a promising technique for reducing the power consumption, which is necessary for supporting future wireless systems comprising a large number of antennas. However, the use of a large number of antennas remains still limited to mobile devices owing to their size. Cooperative communication using a DF relay can resolve this limitation; however, detection errors at the relay make it difficult to employ cooperative communication directly. This difficulty is more severe in a MIMO system using one-bit ADCs due to its nonlinear nature. To efficiently address the difficulty, this paper proposes a detection scheme that mitigates the error propagation effect. The upper bound of the pairwise error probability (PEP) of one-bit ADCs is first derived in a weighted Hamming distance form. Then, using the derived PEP, the proposed detection for the DF relay protocol is derived as a single weighted Hamming distance. Finally, the complexity of the proposed detection is analyzed in terms of real multiplications. The simulation results show that the proposed detection method efficiently mitigates the error propagation effect but has a relatively low level of complexity when compared to conventional detection methods.
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Affiliation(s)
- Tae-Kyoung Kim
- Department of Electronic Engineering, Gachon University, Seongnam 13120, Korea
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15
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Cha Y, Kim TK, Lee J, Kim T, Hong AJ, Zoh KD. Degradation of iopromide during the UV-LED/chlorine reaction: Effect of wavelength, radical contribution, transformation products, and toxicity. J Hazard Mater 2022; 437:129371. [PMID: 35717814 DOI: 10.1016/j.jhazmat.2022.129371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/30/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
Three different UV-LED wavelengths (265, 310, and 365 nm) were used in the UV-LED/chlorine reaction to investigate the degradation mechanism of iopromide (IPM) at different wavelengths, a representative iodinated contrast media compound. The degradation rate (k'IPM) increased from pH 6-8 at 265 nm, but, decreased as the pH increased up to 9 at 310 nm and 365 nm. Radical scavenging experiments showed that reactive chlorine species (RCS) are the dominant radical species at all wavelengths, but a higher contribution of OH• was observed at lower pH and longer wavelengths. The contribution of RCS decreased but the contribution of OH• increased as the wavelength increased. Among RCS, the largest contribution was found to be ClO•. Total nine transformation products (TPs) were identified by LC-QTOF-MS during the UV-LED/chlorine reaction at 265 nm. Based on the identified TPs and their time profiles, we proposed a degradation pathway of IPM during UV-LED/chlorine reaction. The Microtox test using V. fischeri showed that no significant increase in toxicity was observed at all wavelengths. The synergistic effect of UV-LED and chlorine was greater at a higher wavelength by the electrical efficiency per order (EEO) calculation.
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Affiliation(s)
- Youngho Cha
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, South Korea
| | - Tae-Kyoung Kim
- Department of Civil and Environmental Engineering, University of California at Berkeley, CA 94720, USA
| | - Jaewon Lee
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, South Korea
| | - Taeyeon Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, South Korea
| | - Ae-Jung Hong
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, South Korea
| | - Kyung-Duk Zoh
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, South Korea.
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16
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Kim TK, Min M. A Low-Complexity Algorithm for a Reinforcement Learning-Based Channel Estimator for MIMO Systems. Sensors (Basel) 2022; 22:s22124379. [PMID: 35746162 PMCID: PMC9229451 DOI: 10.3390/s22124379] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/02/2022] [Accepted: 06/07/2022] [Indexed: 12/10/2022]
Abstract
This paper proposes a low-complexity algorithm for a reinforcement learning-based channel estimator for multiple-input multiple-output systems. The proposed channel estimator utilizes detected symbols to reduce the channel estimation error. However, the detected data symbols may include errors at the receiver owing to the characteristics of the wireless channels. Thus, the detected data symbols are selectively used as additional pilot symbols. To this end, a Markov decision process (MDP) problem is defined to optimize the selection of the detected data symbols. Subsequently, a reinforcement learning algorithm is developed to solve the MDP problem with computational efficiency. The developed algorithm derives the optimal policy in a closed form by introducing backup samples and data subblocks, to reduce latency and complexity. Simulations are conducted, and the results show that the proposed channel estimator significantly reduces the minimum-mean square error of the channel estimates, thus improving the block error rate compared to the conventional channel estimation.
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Affiliation(s)
- Tae-Kyoung Kim
- Department of Electronic Engineering, Gachon University, Seongnam 13120, Korea;
| | - Moonsik Min
- School of Electronics Engineering, Kyungpook National University, Daegu 41566, Korea
- School of Electronic and Electrical Engineering, Kyungpook National University, Daegu 41566, Korea
- Correspondence:
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17
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Kim TK, Jang M, Hwang YS. Adsorption of benzalkonium chlorides onto polyethylene microplastics: Mechanism and toxicity evaluation. J Hazard Mater 2022; 426:128076. [PMID: 34952503 DOI: 10.1016/j.jhazmat.2021.128076] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/29/2021] [Accepted: 12/10/2021] [Indexed: 06/14/2023]
Abstract
Usage of disposable plastic products and disinfectants has been skyrocketing due to the COVID-19 pandemic. The random disposal of plastic products may result in greater microplastic pollution. Benzalkonium chloride is known as one of the most common ingredients of disinfectants. In this study, the adsorption behavior of benzalkonium chlorides (BAC12, BAC14, BAC16) on polyethylene microplastics (PE-MPs) and the combined toxic effects were investigated using batch adsorption experiment and Daphnia magna. The results showed that PE-MPs had strong adsorption capacity for BACs and the adsorption capacity increased (11.03-22.77 mg g-1) with their octanol-water distribution coefficients. The effect of pH was negligible while dissolved organic matter inhibited the adsorption. A slightly inverse relationship between particle size of PE-MPs and adsorption was observed. Additionally, the MP aging with UV/H2O2 increased the adsorption of BAC12 but decreased that of relatively hydrophobic BAC14 and BAC16. The survival rate of Daphnia magna increased up to 100% in the presence of PE-MPs depending upon their adsorption capacities, suggesting that PE-MPs do not act as a carrier but rather as a scavenger for BACs. This study provides important information necessary for environmental risk assessment with regard to the combined pollution of MPs and toxic chemicals.
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Affiliation(s)
- Tae-Kyoung Kim
- Environmental Fate and Exposure Research Group, Korea Institute of Toxicology, Jinju, Republic of Korea; Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
| | - Minhee Jang
- Environmental Fate and Exposure Research Group, Korea Institute of Toxicology, Jinju, Republic of Korea
| | - Yu Sik Hwang
- Environmental Fate and Exposure Research Group, Korea Institute of Toxicology, Jinju, Republic of Korea.
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18
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Shin MG, Kim YJ, Kim TK, Kang D. Effects of Long Working Hours and Night Work on Subjective Well-Being Depending on Work Creativity and Task Variety, and Occupation: The Role of Working-Time Mismatch, Variability, Shift Work, and Autonomy. Int J Environ Res Public Health 2021; 18:ijerph18126371. [PMID: 34204671 PMCID: PMC8296193 DOI: 10.3390/ijerph18126371] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/04/2021] [Accepted: 06/10/2021] [Indexed: 11/30/2022]
Abstract
This study explored the effects of long working hours (LW) and night work (NW) on subjective well-being and the modifying effects of work creativity and task variety (WCTV) and occupation. In addition, we examined the influence of working time-related variables including working-time mismatch, variability, shift work, and autonomy on the effects of LW and NW. This study used data from the 5th Korean Working Conditions Survey on 50,205 workers. LW and NW were defined as 52–60 h (L1) or >60 h (L2) per week, and 1–10 days (N1) or >10 days (N2) of night work per month. Multiple logistic regression was used to examine the effects of LW and NW and the modifying influences of WCTV and occupation. Differences in ORs of LW and NW caused by working time-related variables were investigated, to determine effect sizes and directions. A high level of WCTV alleviated the risks of LW and NW. White-collar workers were more vulnerable to the risk associated with NW. Regarding working-time related variables, working-time mismatch and variability increased the risks of LW and NW, respectively, while shift work alleviated the risks of NW. In countries where flexible work systems are not well utilized, working-time autonomy might not be associated with the risk of LW or NW. This study showed that it is necessary to comprehensively consider the occupation and task characteristics of individual workers performing LW or NW. Further studies of the modifying effects of working time-related variables on LW and NW are needed.
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Affiliation(s)
- Min-Gwan Shin
- Department of Medicine, Medical College, Pusan National University, Yangsan 50612, Korea;
| | - Yoon-Ji Kim
- Department of Preventive, and Occupational & Environmental Medicine, Medical College, Pusan National University, Yangsan 50612, Korea;
- Environmental Health Center of Asbestos, Pusan National University Yangsan Hospital, Yangsan 50612, Korea
| | - Tae-Kyoung Kim
- Medical Research Institute, Pusan National University, Yangsan 50612, Korea;
| | - Dongmug Kang
- Department of Preventive, and Occupational & Environmental Medicine, Medical College, Pusan National University, Yangsan 50612, Korea;
- Environmental Health Center of Asbestos, Pusan National University Yangsan Hospital, Yangsan 50612, Korea
- Department of Occupational and Environmental Medicine, Pusan National University Yangsan Hospital, Yangsan 50612, Korea
- Correspondence: ; Tel.: +82-51-510-8034
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19
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Kim TK, Kim T, Lee I, Choi K, Zoh KD. Removal of tetramethylammonium hydroxide (TMAH) in semiconductor wastewater using the nano-ozone H 2O 2 process. J Hazard Mater 2021; 409:123759. [PMID: 33451854 DOI: 10.1016/j.jhazmat.2020.123759] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 08/13/2020] [Accepted: 08/19/2020] [Indexed: 06/12/2023]
Abstract
In this study, we used a nano-ozone bubble to enhance the efficiency of the ozone/H2O2 process for the degradation of tetramethylammonium hydroxide (TMAH) found in semiconductor wastewater at high levels. The nano-ozone bubble significantly increased ozone mass transfer rate compared to that of the macro-ozone bubble. The half-life of nano-ozone bubbles was 23 times longer than that of the nano-ozone bubbles. Due to the high ozone mass transfer rate and its durability, the nano-ozone bubble increased the TMAH degradation rate compared to that of the macro-ozone. The addition of H2O2 significantly increased the TMAH degradation rate constant by OH production during the nano-ozone bubbles/H2O2 process. The optimum conditions for TMAH removal was 25 °C and pH 10. Within 90 min of the nano-ozone/H2O2 process, TOC removal was 65 % while 80 % of nitrogen was converted into nitrate (NO3-) with 95 % of TMAM removal. Decreases in acute (40-fold) and chronic (2-fold) toxicity were achieved after applying the nano-ozone/H2O2 process to TMAH containing wastewater. However, there was no significant chronic toxicity decrease during the nano-ozone/H2O2 process of TMAH.
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Affiliation(s)
- Tae-Kyoung Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, Republic of Korea; Environmental Fate and Exposure Research Group, Korea Institute of Toxicology, Jinju, Republic of Korea
| | - Taeyeon Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, Republic of Korea
| | - Inae Lee
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, Republic of Korea
| | - Kyungho Choi
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, Republic of Korea
| | - Kyung-Duk Zoh
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, Republic of Korea.
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20
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Lee JY, Lee YM, Kim TK, Choi K, Zoh KD. Degradation of cyclophosphamide during UV/chlorine reaction: Kinetics, byproducts, and their toxicity. Chemosphere 2021; 268:128817. [PMID: 33162158 DOI: 10.1016/j.chemosphere.2020.128817] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 10/13/2020] [Accepted: 10/27/2020] [Indexed: 06/11/2023]
Abstract
Cyclophosphamide (CP) is a widely used anticancer drug and an immunosuppressant. Since CP is nonbiodegradable, it is hardly removed by the conventional wastewater treatment processes, resulting in continuous detection in surface water. In this study, the degradation of CP during the UV-B/chlorine reaction was investigated. CP was not degraded by UV-B photolysis and chlorination only but was effectively degraded in the UV-B/chlorine reaction with pseudo-first-order kinetics. Acidic pH conditions in the UV-B/chlorine reaction showed the most effective removal of CP. More than 56% of the CP was mineralized within 8 h of the reaction. Seven organic transformation products (TPs) (m/z = 141.01, 192.10, 198.03, 212.01, 258.01, 274.00, and 276.02, respectively) and four inorganic byproducts (NH4+, NO3-, HCOO-, and PO43-) were identified using LC-qTOF/MS and ion chromatography, respectively. Microtox test based on bioluminescence inhibition showed that the toxicity inhibition increased to 88% as the reaction proceeded during the UV/chlorine reaction, probably due to the production of TPs, especially TP 258 (m/z = 258.01). The results of this study imply that the toxicity of TPs needs to be reduced when applying a UV-B/chlorination process to treat CP in water.
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Affiliation(s)
- Ji-Young Lee
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, South Korea
| | - Young-Min Lee
- Institute of Health and Environment, Seoul National University, Seoul, South Korea
| | - Tae-Kyoung Kim
- Environmental Fate and Exposure Research Group, Korea Institute of Toxicology, Jinju, South Korea
| | - Kyungho Choi
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, South Korea; Institute of Health and Environment, Seoul National University, Seoul, South Korea
| | - Kyung-Duk Zoh
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, South Korea; Institute of Health and Environment, Seoul National University, Seoul, South Korea.
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21
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Kim TK, Kim T, Cha Y, Zoh KD. Energy-efficient erythromycin degradation using UV-LED (275 nm)/chlorine process: Radical contribution, transformation products, and toxicity evaluation. Water Res 2020; 185:116159. [PMID: 32791458 DOI: 10.1016/j.watres.2020.116159] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/23/2020] [Accepted: 07/04/2020] [Indexed: 06/11/2023]
Abstract
In this study, we investigated the degradation mechanism of erythromycin (ERY) during UV-LED/chlorine treatment using a 275-nm ultraviolet light-emitting diode (UV-LED). This wavelength is known to generate fewer disinfection byproducts (DBPs), and to have higher energy and photon yield efficiency compared to low pressure mercury (LP-UV) lamp which emits 254 nm of UV radiation. The degradation of ERY during the UV-LED/chlorine reaction followed pseudo-first-order kinetics. While Cl• and ClO• radicals along with other secondary radicals played key roles in the degradation of ERY at alkaline pH conditions, •OH radical was the main contributor at acidic pH conditions. Using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QToF-MS), we tentatively identified six byproducts. Trace amounts of DBPs, such as chloroform (CHCl3) and chlorate (ClO3-) ions, were also detected at less than 0.3 mg/L. There was no residual antibiotic effect at the end of the UV-LED/chlorine reaction due to the complete degradation of important moieties, such as macrolide, in ERY. Toxicity decreased by 20% after 20 min during the UV-LED/chlorine process of ERY (1.0 mg/L) degradation. Finally, we confirmed the inactivation of ARB and ARG during the UV-LED/chlorine process.
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Affiliation(s)
- Tae-Kyoung Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, 08826, South Korea
| | - Taeyeon Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, 08826, South Korea
| | - Youngho Cha
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, 08826, South Korea
| | - Kyung-Duk Zoh
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, 08826, South Korea.
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22
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Kim TK. Antenna Combining for Interference Limited MIMO Cellular Networks. Sensors (Basel) 2020; 20:s20154210. [PMID: 32751144 PMCID: PMC7435820 DOI: 10.3390/s20154210] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 11/05/2022]
Abstract
This paper considers a downlink cellular network where multi-antenna base stations (BSs) simultaneously serve their associated multi-antenna users. Each BS is distributed according to a homogeneous Poisson point process and uses zero-forcing beamforming for spatial division multiplexing with partial channel state information (CSI). During downlink transmission, each user combines the multiple antenna outputs and quantizes the CSI to feed back to its associated BS. Specifically, this paper focuses on antenna combining at the receiver. Conventional quantization-based combining (QBC) effectively reduces the quantization error; however, inter-cell interference in the cellular networks degrades the QBC gain. This degradation is analyzed using a spherical-cap approximation of vector quantization (SCVQ). From the SCVQ, the ergodic spectral efficiency and the optimal number of feedback bits are investigated, and it is shown that the QBC degrades the gain of the effective channel. To address this problem, an optimization solution is proposed that selects the antenna combining to maximize the spectral efficiency. The solution is also derived by considering the expected beamforming vectors of other cells. It is demonstrated by simulation that the proposed solution outperforms the conventional methods.
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Affiliation(s)
- Tae-Kyoung Kim
- Department of Electronics, Information and Communication Engineering, Mokpo National University, Muan, Jeonnam 58554, Korea
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23
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Noguchi R, Takahashi T, Kuroda K, Ochi M, Shirasawa T, Sakano M, Bareille C, Nakayama M, Watson MD, Yaji K, Harasawa A, Iwasawa H, Dudin P, Kim TK, Hoesch M, Kandyba V, Giampietri A, Barinov A, Shin S, Arita R, Sasagawa T, Kondo T. Publisher Correction: A weak topological insulator state in quasi-one-dimensional bismuth iodide. Nature 2020; 584:E4. [PMID: 32690939 DOI: 10.1038/s41586-020-2392-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Affiliation(s)
- Ryo Noguchi
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Japan
| | - T Takahashi
- Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Japan
| | - K Kuroda
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Japan
| | - M Ochi
- Department of Physics, Osaka University, Toyonaka, Japan
| | - T Shirasawa
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - M Sakano
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Japan.,Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo, Japan
| | - C Bareille
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Japan
| | - M Nakayama
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Japan
| | - M D Watson
- Diamond Light Source, Harwell Campus, Didcot, UK
| | - K Yaji
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Japan
| | - A Harasawa
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Japan
| | - H Iwasawa
- Diamond Light Source, Harwell Campus, Didcot, UK.,Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Japan
| | - P Dudin
- Diamond Light Source, Harwell Campus, Didcot, UK
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot, UK
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot, UK.,DESY Photon Science, Deutsches Elektronen-Synchrotron, Hamburg, Germany
| | - V Kandyba
- Elettra - Sincrotrone Trieste, Basovizza, Italy
| | | | - A Barinov
- Elettra - Sincrotrone Trieste, Basovizza, Italy
| | - S Shin
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Japan
| | - R Arita
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
| | - T Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Japan.
| | - Takeshi Kondo
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Japan.
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24
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Kang YM, Kim TK, Kim MK, Zoh KD. Greenhouse gas emissions from advanced oxidation processes in the degradation of bisphenol A: a comparative study of the H 2O 2/UV, TiO 2 /UV, and ozonation processes. Environ Sci Pollut Res Int 2020; 27:12227-12236. [PMID: 31984463 DOI: 10.1007/s11356-020-07807-3] [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] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/21/2020] [Indexed: 06/10/2023]
Abstract
To estimate greenhouse gas (GHG) emissions and degradation rate constants (kobs) from H2O2/UV-C, TiO2/UV-C, and ozonation processes in the degradation of bisphenol A (BPA), the laboratory scale experiments were conducted. In the H2O2/UV-C process, the fastest degradation rate constant (kobs = 0.353 min-1) was observed at 4 mM of H2O2, while the minimum GHG emission was achieved at 3 mM of H2O2. In the TiO2/UV-C process, the fastest rate constant (kobs = 0.126 min-1) was achieved at 2000 mg/L of TiO2, while the minimum GHG emission was observed at 400 mg/L of TiO2. In the ozonation process, GHG emissions were minimal at 5 mg/L of O3, but the degradation rate constant kept on increasing as the O3 concentration increased. There were three major types of GHG emissions in the advanced oxidation processes (AOPs). In the ozonation process, most of the GHG emissions were generated by electricity consumption. TiO2/UV-C process accounted for a significant portion of the GHGs generated by the use of chemicals. Finally, the H2O2/UV-C process produced similar GHG emissions from both chemical inputs and electricity consumption. The carbon footprint calculation revealed that for the treatment of 1 m3 of water contaminated with 0.04 mM BPA, the H2O2/UV-C process had the smallest carbon footprint (0.565 kg CO2 eq/m3), followed by the TiO2/UV-C process (3.445 kg CO2 eq/m3) and the ozonation process (3.897 kg CO2 eq/m3). Our results imply that the increase in removal rate constant might not be the optimal parameter for reducing GHG emissions during the application of these processes. Graphical abstract .
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Affiliation(s)
- Young-Min Kang
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, 08826, South Korea
| | - Tae-Kyoung Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, 08826, South Korea
| | - Moon-Kyung Kim
- Institute of Health and Environment, Seoul National University, Seoul, 08826, South Korea
| | - Kyung-Duk Zoh
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, 08826, South Korea.
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Cucchi I, Marrazzo A, Cappelli E, Riccò S, Bruno FY, Lisi S, Hoesch M, Kim TK, Cacho C, Besnard C, Giannini E, Marzari N, Gibertini M, Baumberger F, Tamai A. Bulk and Surface Electronic Structure of the Dual-Topology Semimetal Pt_{2}HgSe_{3}. Phys Rev Lett 2020; 124:106402. [PMID: 32216410 DOI: 10.1103/physrevlett.124.106402] [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: 09/13/2019] [Accepted: 02/14/2020] [Indexed: 06/10/2023]
Abstract
We report high-resolution angle-resolved photoemission measurements on single crystals of Pt_{2}HgSe_{3} grown by high-pressure synthesis. Our data reveal a gapped Dirac nodal line whose (001) projection separates the surface Brillouin zone in topological and trivial areas. In the nontrivial k-space range, we find surface states with multiple saddle points in the dispersion, resulting in two van Hove singularities in the surface density of states. Based on density-functional theory calculations, we identify these surface states as signatures of a topological crystalline state, which coexists with a weak topological phase.
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Affiliation(s)
- I Cucchi
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - A Marrazzo
- Theory and Simulation of Materials (THEOS), and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - E Cappelli
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - S Riccò
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - F Y Bruno
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
- GFMC, Departamento de Física de Materiales, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - S Lisi
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
- Deutsches Elektronen-Synchrotron DESY, Photon Science, 22607 Hamburg, Germany
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - C Cacho
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - C Besnard
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - E Giannini
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - N Marzari
- Theory and Simulation of Materials (THEOS), and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - M Gibertini
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
- Theory and Simulation of Materials (THEOS), and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - F Baumberger
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - A Tamai
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
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26
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Kim HJ, Oh SY, Won SY, Kim HJ, Kim TK, Ko BC, Woo SY, Park EC. Associations between earplug use and hearing loss in ROK military personnel. BMJ Mil Health 2020; 167:398-401. [PMID: 32139412 PMCID: PMC8639962 DOI: 10.1136/jramc-2019-001378] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 12/14/2019] [Accepted: 12/17/2019] [Indexed: 12/05/2022]
Abstract
Introduction The easiest way to prevent noise-induced hearing loss (NIHL) is to wear earplugs. The Republic of Korea (ROK) Ministry of National Defense (MND) is supplying earplugs to prevent NIHL, but many patients still suffer from this. We speculated that earplugs would have a high NIHL rate, depending on the rate of use of earplugs, regardless of the rate of supply. Therefore, we conducted this study to investigate the relationship between the use of earplugs and hearing loss by ROK military personnel. Methods The study used data from the Military Health Survey conducted in 2014–2015, which included 13 470 questionnaires completed by ROK military personnel. Hearing loss and earplug use were self-reported. Logistic regression analysis was used to assess associations between earplug use and hearing loss. Results The study sample included 13 470 ROK military personnel (response rate of 71.2%) (Army, 8330 (61.8%); Navy/Marines, 2236 (16.6%); and Air Force, 2904 (21.6%)). Overall, 18.8% of Korean military personnel reported that they always wore earplugs, and 2.8% reported hearing loss. In logistic regression analysis, there were significant differences in the rates of hearing loss associated with wearing earplugs sometimes (OR=1.48, 95% CI 1.07 to 2.05) and never wearing earplugs (OR=1.53, 95% CI 1.12 to 2.10). In subgroup analysis, in Air Force, non-combat branch, forward area and long-term military service personnel increased hearing loss was associated with not wearing earplugs. Conclusion Our study confirmed that within the ROK military, there is an association between hearing loss and lack of earplug use. In the ROK MND, Army, Navy/Marines and Air Force headquarters must provide guidelines for the use of earplugs during field training to protect military personnel’s hearings and, if necessary, need to be regulated or institutionalised.
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Affiliation(s)
- Hwi Jun Kim
- Department of Public Health, Graduate School, Yonsei University, Seodaemun-gu, Seoul, Republic of Korea
| | - S Y Oh
- Department of Public Health, Graduate School, Yonsei University, Seodaemun-gu, Seoul, Republic of Korea
| | - S Y Won
- Division of Management Logistics, Korea Ministry of National Defense, Seoul, Republic of Korea
| | - H J Kim
- Division of Medical Corps, Second Operational Command, Daegu, Republic of Korea
| | - T K Kim
- Secretary's office, Armed Forces Medical Command, Seongnam, Republic of Korea
| | - B C Ko
- Department of Operation, 7th Division Medical Detachment, Seoul, Republic of Korea
| | - S Y Woo
- Department of Nursing, Yonsei University, Seodaemun-gu, Seoul, Republic of Korea
| | - E-C Park
- Department of Preventive Medicine, Yonsei University College of Medicine, Seodaemun-gu, Seoul, Republic of Korea
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27
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Kang YM, Kim MK, Kim T, Kim TK, Zoh KD. Occurrence and Fate of Micropollutants in Private Wastewater Treatment Facility (WTF) and Their Impact on Receiving Water. Environ Manage 2019; 64:650-660. [PMID: 31606773 DOI: 10.1007/s00267-019-01211-5] [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] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 10/01/2019] [Indexed: 06/10/2023]
Abstract
This study investigated the occurrence and removals of micropollutants in the sewage treatment tank (STT) which is a typical private wastewater treatment facility used in the rural communities in Korea, and their impact on receiving water. STTs were selected in eight provinces to examine the regional difference in the composition of micropollutant occurrence. We measured ten selected micropollutants in influents and effluents of STTs, as well as upstream and downstream of its receiving surface water. The dominant micropollutants in the influent of the STTs were caffeine (13,346 ng/L), acetaminophen (11,331 ng/L), ibuprofen (1440 ng/L), and naproxen (1313 ng/L), in agreement with the amounts produced annually in Korea. In the effluent, caffeine (1912 ng/L), acetaminophen (1586 ng/L), naproxen (475 ng/L), and ibuprofen (389 ng/L) were detected in relatively high concentrations. The composition of micropollutants in STT influents showed little regional variation by provinces, suggesting that the consumption pattern of these micropollutants did not show regional variation. The removal efficiencies of the selected micropollutants at the STTs ranged from 12% (carbamazepine) to 88% (acetaminophen), lower than typical removal by sewage treatment plants (STPs). This result is probably due to the automatic operation systems and simple treatment processes in STTs compared with STPs. The concentrations of selected micropollutants upstream of the receiving water were generally lower compared with those observed downstream, indicating that effluent from STTs was the main source. The per capita discharge loads of STTs and annual emissions rates (kg/year) from private wastewater treatment facilities were estimated for the selected micropollutants.
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Affiliation(s)
- Young-Min Kang
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, 08826, Korea
| | - Moon-Kyung Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, 08826, Korea
- Institute of Health and Environment, Seoul National University, Seoul, 08826, Korea
| | - Taeyeon Kim
- Institute of Health and Environment, Seoul National University, Seoul, 08826, Korea
| | - Tae-Kyoung Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, 08826, Korea
| | - Kyung-Duk Zoh
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, 08826, Korea.
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28
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Kim T, Kim TK, Zoh KD. Degradation kinetics and pathways of β-cyclocitral and β-ionone during UV photolysis and UV/chlorination reactions. J Environ Manage 2019; 239:8-16. [PMID: 30877971 DOI: 10.1016/j.jenvman.2019.03.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 02/12/2019] [Accepted: 03/06/2019] [Indexed: 06/09/2023]
Abstract
β-cyclocitral and β-ionone are ones of major algal odorants produced by oxidation of the β-carotene that exists in algae cells. These compounds degraded the quality of drinking water therefore it needed to be treated in drinking water treatment by advanced oxidation processes. In this study, UV photolysis and UV-chlorination reactions along with chlorination to remove these odorants in water were compared. Kinetics of three reactions were well fitted at pseudo-first order model. Among three reactions, UV-chlorination was the most effective due to generation of OH and Cl radicals. β-ionone showed faster degradation compared to β-cyclocitral due to the existence of double bond in the alkyl carbon chain. In addition, radical contributions of degradation of odorants were examined. During UV-chlorination, UV photolysis contributed around 50% of removal for two odorants. OH radical took part of 36% removal of β-ionone and 50% removal of β-cyclocitral. Unlike β-ionone, β-cyclocitral was not degraded by reactive chlorine species during UV-chlorination. Acidic pH was favorable for UV-chlorination due to different quantum yield and radical scavenging effect by chlorine species. Formation of trace amount of chloroform was observed during UV-chlorination. The methyl ketone group of β-ionone was the main site for chloroform production. Several byproducts during UV photolysis and UV-chlorination of β-ionone were identified by GC-MS, and these were degraded with further reaction by UV-induced isomerization, OH radical, and bond scission mechanisms. β-cyclocitral was formed as byproducts during UV-chlorination of β-ionone. Based on degradation byproducts, the degradation pathways of β-ionone and β-cyclocitral of UV photolysis and UV-chlorination were suggested based on the identified byproducts. This study showed UV-chlorination process can be applied for degrading odorants like β-cyclocitral and β-ionone.
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Affiliation(s)
- Taeyeon Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Tae-Kyoung Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Kyung-Duk Zoh
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea.
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29
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Kim TK, Kim T, Jo A, Park S, Choi K, Zoh KD. Degradation mechanism of cyanide in water using a UV-LED/H 2O 2/Cu 2+ system. Chemosphere 2018; 208:441-449. [PMID: 29886332 DOI: 10.1016/j.chemosphere.2018.05.198] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/25/2018] [Accepted: 05/31/2018] [Indexed: 06/08/2023]
Abstract
In this study, we developed a UV-LED/H2O2/Cu2+ system to remove cyanide, which is typically present in metal electroplating wastewater. The results showed the synergistic effects of UV-LED, H2O2, and Cu2+ ions on cyanide removal in comparison with UV-LED photolysis, H2O2 oxidation, UV-LED/H2O2, and H2O2/Cu2+ systems. Cyanide was removed completely in 30 min in the UV-LED/H2O2/Cu2+ system, and its loss followed pseudo-first order kinetics. Statistically, both H2O2 and Cu2+ ions showed positive effects on cyanide removal, but Cu2+ ions exhibited a greater effect. The highest cyanide removal rate constant (k = 0.179 min-1) was achieved at pH 11, but the lowest was achieved at pH 12.5 (k = 0.064 min-1) due to the hydrolysis of H2O2 (pKa of H2O2 = 11.75). The presence of dissolved organic matter (DOM) inhibited cyanide removal, and the removal rate constant exhibited a negative linear correlation with DOM (R2 = 0.987). The removal rate of cyanide was enhanced by the addition of Zn2+ ions (from 0.179 to 0.457 min-1), while the co-existence of Ni2+ or Cr+6 ion with Cu2+ ion reduced cyanide removal. The formation of OH radicals in the UV-LED/H2O2/Cu2+ system was verified using an aminophenyl fluorescence (APF) probe. Cyanate ions and ammonia were detected as the byproducts of cyanide decomposition. Finally, an acute toxicity reduction of 64.6% was achieved in the system within 1 h, despite a high initial cyanide concentration (100 mg/L). In terms of removal efficiency and toxicity reduction, the UV-LED/H2O2/Cu2+ system may be an alternative method of cyanide removal from wastewaters.
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Affiliation(s)
- Tae-Kyoung Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1Gwanak-ro, Gwanak-gu, Seoul, South Korea
| | - Taeyeon Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1Gwanak-ro, Gwanak-gu, Seoul, South Korea
| | - Areum Jo
- Risk Assessment Division, National Institute of Environmental Research, Hwangyeong-ro 42, Seo-gu, Incheon, South Korea
| | - Suhyun Park
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1Gwanak-ro, Gwanak-gu, Seoul, South Korea
| | - Kyungho Choi
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1Gwanak-ro, Gwanak-gu, Seoul, South Korea
| | - Kyung-Duk Zoh
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1Gwanak-ro, Gwanak-gu, Seoul, South Korea.
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Clark OJ, Neat MJ, Okawa K, Bawden L, Marković I, Mazzola F, Feng J, Sunko V, Riley JM, Meevasana W, Fujii J, Vobornik I, Kim TK, Hoesch M, Sasagawa T, Wahl P, Bahramy MS, King PDC. Fermiology and Superconductivity of Topological Surface States in PdTe_{2}. Phys Rev Lett 2018; 120:156401. [PMID: 29756894 DOI: 10.1103/physrevlett.120.156401] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/17/2018] [Indexed: 05/12/2023]
Abstract
We study the low-energy surface electronic structure of the transition-metal dichalcogenide superconductor PdTe_{2} by spin- and angle-resolved photoemission, scanning tunneling microscopy, and density-functional theory-based supercell calculations. Comparing PdTe_{2} with its sister compound PtSe_{2}, we demonstrate how enhanced interlayer hopping in the Te-based material drives a band inversion within the antibonding p-orbital manifold well above the Fermi level. We show how this mediates spin-polarized topological surface states which form rich multivalley Fermi surfaces with complex spin textures. Scanning tunneling spectroscopy reveals type-II superconductivity at the surface, and moreover shows no evidence for an unconventional component of its superconducting order parameter, despite the presence of topological surface states.
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Affiliation(s)
- O J Clark
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - M J Neat
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - K Okawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - L Bawden
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - I Marković
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - F Mazzola
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - J Feng
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
- Suzhou Institute of Nano-Tech. and Nanobionics (SINANO), CAS, 398 Ruoshui Road, SEID, SIP, Suzhou 215123, China
| | - V Sunko
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - J M Riley
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - W Meevasana
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
- ThEP, Commission of Higher Education, Bangkok 10400, Thailand
| | - J Fujii
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - I Vobornik
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - T Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - P Wahl
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - M S Bahramy
- Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- RIKEN center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - P D C King
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
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Lee SY, Kim TK, Cheon KA, Song DH. Aftermath of Child Sexual Abuse in Children in Korea: Data from the Nation-Funded Sexual Violence Victim Protection Center for Children. Soa Chongsonyon Chongsin Uihak 2018; 29:32-39. [PMID: 32595293 PMCID: PMC7298898 DOI: 10.5765/jkacap.2018.29.2.32] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/22/2017] [Accepted: 10/25/2017] [Indexed: 11/08/2022] Open
Abstract
Objectives: This study aimed to investigate the 3-year mean periods aftermath of child sexual abuse and to compare the sexual violence victims regard to the treatment. Methods: 682 sexual violence victims were recruited by Seoul Sunflower Children Center, a nation-funded sexual violence victim protection center for children age 13, from 2004 to 2008. Data from 49 victims among 116 consented a follow-up, were analyzed. The victims were assessed by psychological test. Data was analyzed by SPSS ver. 15.0 (SPSS Inc.). Results: The average time elapsed from the last presumed sexual abuse was 39.7 months [standard deviation (SD) 26.02]. Overall, Children’s Depression Inventory (CDI) was significantly decreased from 15.8 (SD 9.33) to 10.4 (SD 9.98), and several subscales (depression, anxiety, anger, posttraumatic stress, and dissociation) of Trauma Symptom Checklist for Children (TSCC) were also significantly decreased. CDI and TSCC scores showed no statistical difference between treatment-given and not-given groups, but Revised Children’s Manifest Anxiety Scale (RCMAS) was decreased in treatment-given group, whereas it was increased in treatment-not-given group. The difference of RCMAS scores between the two groups was statistically significant [F(1,28)=4.54, p<0.05]. Conclusion: Sexually abused children showed overall symptom decreases over time, but anxiety was not decreased in treatment not-given group.
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Affiliation(s)
| | - Tae-Kyoung Kim
- Department of Counseling Psychology, Woosuk University, Wanju, Korea
| | - Keun-Ah Cheon
- Department of Psychiatry, College of Medicine, Yonsei University, Seoul, Korea.,Institute of Behavioral Science in Medicine, College of Medicine, Yonsei University, Seoul, Korea
| | - Dong-Ho Song
- Department of Psychiatry, College of Medicine, Yonsei University, Seoul, Korea.,Institute of Behavioral Science in Medicine, College of Medicine, Yonsei University, Seoul, Korea
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Sunko V, Rosner H, Kushwaha P, Khim S, Mazzola F, Bawden L, Clark OJ, Riley JM, Kasinathan D, Haverkort MW, Kim TK, Hoesch M, Fujii J, Vobornik I, Mackenzie AP, King PDC. Maximal Rashba-like spin splitting via kinetic-energy-coupled inversion-symmetry breaking. Nature 2018; 549:492-496. [PMID: 28959958 DOI: 10.1038/nature23898] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 07/26/2017] [Indexed: 11/09/2022]
Abstract
Engineering and enhancing the breaking of inversion symmetry in solids-that is, allowing electrons to differentiate between 'up' and 'down'-is a key goal in condensed-matter physics and materials science because it can be used to stabilize states that are of fundamental interest and also have potential practical applications. Examples include improved ferroelectrics for memory devices and materials that host Majorana zero modes for quantum computing. Although inversion symmetry is naturally broken in several crystalline environments, such as at surfaces and interfaces, maximizing the influence of this effect on the electronic states of interest remains a challenge. Here we present a mechanism for realizing a much larger coupling of inversion-symmetry breaking to itinerant surface electrons than is typically achieved. The key element is a pronounced asymmetry of surface hopping energies-that is, a kinetic-energy-coupled inversion-symmetry breaking, the energy scale of which is a substantial fraction of the bandwidth. Using spin- and angle-resolved photoemission spectroscopy, we demonstrate that such a strong inversion-symmetry breaking, when combined with spin-orbit interactions, can mediate Rashba-like spin splittings that are much larger than would typically be expected. The energy scale of the inversion-symmetry breaking that we achieve is so large that the spin splitting in the CoO2- and RhO2-derived surface states of delafossite oxides becomes controlled by the full atomic spin-orbit coupling of the 3d and 4d transition metals, resulting in some of the largest known Rashba-like spin splittings. The core structural building blocks that facilitate the bandwidth-scaled inversion-symmetry breaking are common to numerous materials. Our findings therefore provide opportunities for creating spin-textured states and suggest routes to interfacial control of inversion-symmetry breaking in designer heterostructures of oxides and other material classes.
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Affiliation(s)
- Veronika Sunko
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK.,Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - H Rosner
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - P Kushwaha
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - S Khim
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - F Mazzola
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK
| | - L Bawden
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK
| | - O J Clark
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK
| | - J M Riley
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK.,Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - D Kasinathan
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - M W Haverkort
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany.,Institute for Theoretical Physics, Heidelberg University, Philosophenweg 19, 69120 Heidelberg, Germany
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - J Fujii
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
| | - I Vobornik
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
| | - A P Mackenzie
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK.,Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - P D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK
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Bahramy MS, Clark OJ, Yang BJ, Feng J, Bawden L, Riley JM, Marković I, Mazzola F, Sunko V, Biswas D, Cooil SP, Jorge M, Wells JW, Leandersson M, Balasubramanian T, Fujii J, Vobornik I, Rault JE, Kim TK, Hoesch M, Okawa K, Asakawa M, Sasagawa T, Eknapakul T, Meevasana W, King PDC. Ubiquitous formation of bulk Dirac cones and topological surface states from a single orbital manifold in transition-metal dichalcogenides. Nat Mater 2018; 17:21-28. [PMID: 29180775 DOI: 10.1038/nmat5031] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 10/13/2017] [Indexed: 05/12/2023]
Abstract
Transition-metal dichalcogenides (TMDs) are renowned for their rich and varied bulk properties, while their single-layer variants have become one of the most prominent examples of two-dimensional materials beyond graphene. Their disparate ground states largely depend on transition metal d-electron-derived electronic states, on which the vast majority of attention has been concentrated to date. Here, we focus on the chalcogen-derived states. From density-functional theory calculations together with spin- and angle-resolved photoemission, we find that these generically host a co-existence of type-I and type-II three-dimensional bulk Dirac fermions as well as ladders of topological surface states and surface resonances. We demonstrate how these naturally arise within a single p-orbital manifold as a general consequence of a trigonal crystal field, and as such can be expected across a large number of compounds. Already, we demonstrate their existence in six separate TMDs, opening routes to tune, and ultimately exploit, their topological physics.
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Affiliation(s)
- M S Bahramy
- Quantum-Phase Electronics Center and Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
- RIKEN center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - O J Clark
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - B-J Yang
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Korea
- Center for Theoretical Physics (CTP), Seoul National University, Seoul 08826, Korea
| | - J Feng
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
- Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO) CAS, 398 Ruoshi Road, SEID, SIP, Suzhou 215123, China
| | - L Bawden
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - J M Riley
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - I Marković
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - F Mazzola
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - V Sunko
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - D Biswas
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - S P Cooil
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - M Jorge
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - J W Wells
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - M Leandersson
- MAX IV Laboratory, Lund University, PO Box 118, 221 00 Lund, Sweden
| | | | - J Fujii
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - I Vobornik
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - J E Rault
- Synchrotron SOLEIL, CNRS-CEA, L'Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - K Okawa
- Laboratory for Materials and Structures, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - M Asakawa
- Laboratory for Materials and Structures, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - T Sasagawa
- Laboratory for Materials and Structures, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - T Eknapakul
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - W Meevasana
- School of Physics and Center of Excellence on Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
- ThEP, Commission of Higher Education, Bangkok 10400, Thailand
| | - P D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
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34
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Moon BR, Kim TK, Kim MK, Choi J, Zoh KD. Degradation mechanisms of Microcystin-LR during UV-B photolysis and UV/H 2O 2 processes: Byproducts and pathways. Chemosphere 2017; 185:1039-1047. [PMID: 28764099 DOI: 10.1016/j.chemosphere.2017.07.104] [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] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 07/03/2017] [Accepted: 07/18/2017] [Indexed: 06/07/2023]
Abstract
The removal and degradation pathways of microcystin-LR (MC-LR, [M+H]+ = 995.6) in UV-B photolysis and UV-B/H2O2 processes were examined using liquid chromatography-tandem mass spectrometry. The UV/H2O2 process was more efficient than UV-B photolysis for MC-LR removal. Eight by-products were newly identified in the UV-B photolysis ([M+H]+ = 414.3, 417.3, 709.6, 428.9, 608.6, 847.5, 807.4, and 823.6), and eleven by-products were identified in the UV-B/H2O2 process ([M+H]+ = 707.4, 414.7, 429.3, 445.3, 608.6, 1052.0, 313.4, 823.6, 357.3, 245.2, and 805.7). Most of the MC-LR by-products had lower [M+H]+ values than the MC-LR itself during both processes, except for the [M+H]+ value of 1052.0 during UV-B photolysis. Based on identified by-products and peak area patterns, we proposed potential degradation pathways during the two processes. Bond cleavage and intramolecular electron rearrangement by electron pair in the nitrogen atom were the major reactions during UV-B photolysis and UV-B/H2O2 processes, and hydroxylation by OH radical and the adduct formation reaction between the produced by-products were identified as additional pathways during the UV-B/H2O2 process. Meanwhile, the degradation by-products identified from MC-LR during UV-B/H2O2 process can be further degraded by increasing H2O2 dose.
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Affiliation(s)
- Bo-Ram Moon
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul 08826, South Korea
| | - Tae-Kyoung Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul 08826, South Korea
| | - Moon-Kyung Kim
- Institute of Health & Environment, Seoul National University, Seoul 08826, South Korea
| | - Jaewon Choi
- Water Quality Research Center, K-water, Daejeon 34350, South Korea
| | - Kyung-Duk Zoh
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul 08826, South Korea; Institute of Health & Environment, Seoul National University, Seoul 08826, South Korea.
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35
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Kim M, Lee EJ, Shin HM, Jung HS, Kim TK, Kim TN, Kwon MJ, Lee SH, Rhee BD, Park JH. The effect of PPARγ agonist on SGLT2 and glucagon expressions in alpha cells under hyperglycemia. J Endocrinol Invest 2017; 40:1069-1076. [PMID: 28391584 DOI: 10.1007/s40618-017-0659-1] [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] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 03/17/2017] [Indexed: 12/28/2022]
Abstract
BACKGROUND Although sodium glucose cotransporter 2 (SGLT2) inhibitors have many beneficial effects for type 2 diabetes, including decreased cardiovascular death, recent reports that they increased glucagon through SGLT2 inhibition raised some concern. Troglitazone, Peroxisome proliferator-activated receptor γ (PPAR-γ) agonist, was reported to increase SGLT2 in renal proximal tubule cells, but its role on pancreatic alpha cells have not been reported. We investigated the effect of troglitazone on SGLT2 expression in alpha cells and subsequent glucagon regulation in hyperglycemia. METHODS An Alpha TC1-6 cell line was cultured in control (5 mM) or hyperglycemia (HG, 15 mM) for 72 h. We applied troglitazone with or without PPARγ antagonist (GW9662 10 μM). To investigate the involvement of PI3K/Akt pathway, we applied troglitazone with or without Wortmanin. We measured sodium glucose transporter 2 (SGLT2) and glucagon (GCG) mRNA and protein expression. PPAR gamma, PI3K and Akt protein were also measured. RESULTS Exposure of alpha TC cells to HG for 72 h increased glucagon mRNA and protein expression. HG decreased SGLT2 mRNA and protein expression. Troglitazone significantly reversed HG-induced reduction of SGLT2 expression and increase of glucagon secretion. PPARγ antagonist (GW9662 10 μM) decreased the expression of SGLT2 and increased glucagon as HG did. Hyperglycemia increased PI3K and pAkt expression in alpha cells. Wortmanin (PI3K inhibitor, 1 μM) reversed HG-induced SGLT2 decrease and glucagon increase. Troglitazone treatment decreased PI3K and pAkt expression in HG. CONCLUSION In conclusion, PPARγ agonist, troglitazone improved glucose transport SGLT2 dysfunction and subsequent glucagon dysregulation in alpha cell under hyperglycemia. Those effects were through the involvement of PI3K/pAkt signaling pathway. This study may add one more reason for the ideal combination of PPARγ agonist and SGLT2 inhibitor in clinical practice.
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Affiliation(s)
- M Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea.
- Molecular Therapy Lab, Paik Institute for Clinical Research, Inje University, Busan, South Korea.
| | - E J Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
| | - H M Shin
- Molecular Therapy Lab, Paik Institute for Clinical Research, Inje University, Busan, South Korea
| | - H S Jung
- Molecular Therapy Lab, Paik Institute for Clinical Research, Inje University, Busan, South Korea
| | - T K Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
| | - T N Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
| | - M J Kwon
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
| | - S H Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
| | - B D Rhee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
| | - J H Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
- Molecular Therapy Lab, Paik Institute for Clinical Research, Inje University, Busan, South Korea
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36
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Cho YJ, Jo WY, Oh H, Koo CH, Oh J, Cho JY, Yu KS, Jeon Y, Kim TK. Performance of the Minto model for the target-controlled infusion of remifentanil during cardiopulmonary bypass. Anaesthesia 2017; 72:1196-1205. [PMID: 28891056 DOI: 10.1111/anae.14019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2017] [Indexed: 02/05/2023]
Abstract
We studied the predictive performance of the Minto pharmacokinetic model during cardiopulmonary bypass in patients undergoing cardiac surgery. Patients received remifentanil target-controlled infusion using the Minto model during total intravenous anaesthesia with propofol. From 56 patients, 275 arterial blood samples were drawn before, during and after bypass to determine the plasma concentration of remifentanil, and the predicted concentrations were recorded at each time. For pooled data, the median prediction error and median absolute prediction error were 21.3% and 21.8%, respectively, and 22.1% and 22.3% during bypass. Both were 148.4% during hypothermic circulatory arrest and measured concentrations were more than three times greater than predicted (26.9 (17.0) vs. 7.1 (1.6) ng.ml-1 ). The Minto model showed considerable bias but overall acceptable precision during bypass. The target concentration of remifentanil should be reduced when using the Minto model during hypothermic circulatory arrest.
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Affiliation(s)
- Y J Cho
- Department of Anaesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, South Korea
| | - W Y Jo
- Department of Anaesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, South Korea
| | - H Oh
- Department of Anaesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, South Korea
| | - C-H Koo
- CHA Bundang Medical Centre, Department of Anaesthesiology and Pain Medicine, Seongnam-si, South Korea
| | - J Oh
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, South Korea
| | - J-Y Cho
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, South Korea
| | - K-S Yu
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, South Korea
| | - Y Jeon
- Department of Anaesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, South Korea
| | - T K Kim
- Department of Anaesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, South Korea
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37
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Sharma G, Liu D, Malhotra R, Zhou YX, Akagi M, Kim TK. Availability of Additional Mediolateral Implant Option During Total Knee Arthroplasty Improves Femoral Component Fit Across Ethnicities: Results of a Multicenter Study. JB JS Open Access 2017; 2:e0014. [PMID: 30229215 PMCID: PMC6132471 DOI: 10.2106/jbjs.oa.16.00014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Background: Anatomical variation may represent a challenge in achieving a close fit between a prosthesis and a patient’s osseous geometry in total knee arthroplasty (TKA). The purposes of this study were to determine whether the shape of the distal part of the femur differs among ethnicities, whether these differences affect the fit of the femoral component of a standard prosthesis, and whether the additional availability of a femoral component with a reduced mediolateral dimension for the same anteroposterior dimension improves femoral component fit across ethnicities. Methods: Femoral dimensions were measured intraoperatively during 967 TKAs performed using the same type of prosthesis in patients of 5 different ethnicities. Aspect ratios were calculated to determine whether the shapes of the femora differed among ethnicities. The component fit (“perfect,” overhang, or underhang) when only standard prostheses were available was compared with the fit when both standard and narrow prostheses were available in all ethnic groups. This enabled us to determine whether the femoral component fit was improved by the additional availability of the narrow version. Results: Wide variations in shape were found among ethnicities as were variations among individuals of the same ethnicity. Differences in shape among ethnicities influenced the rate of overhang. However, overhang was more frequent at the trochlear than at the condylar level across all ethnicities. The availability of both the standard and the narrow femoral components improved the rate of a perfect fit in women in 3 of the 5 ethnic groups and reduced the overhang rate in women in all 5 of the ethnic groups. In contrast, only modest improvements in femoral component fit, which were not statistically significant, were seen in men. Conclusions: The shape of the distal part of the femur varies not only among ethnicities but also within ethnic groups, leading to a high prevalence of overhang when only standard prostheses are available. The additional availability of a femoral component with a reduced mediolateral dimension for the same anteroposterior size can reduce overhang and improve component fit across ethnicities.
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Affiliation(s)
- Gaurav Sharma
- Joint Reconstruction Center, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Republic of Korea
| | - David Liu
- Gold Coast Centre for Bone and Joint Surgery, John Flynn Private Hospital, Gold Coast, Queensland, Australia
| | - Rajesh Malhotra
- Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India
| | - Yi Xin Zhou
- Department of Orthopaedic Surgery, Beijing Jishuitan Hospital, Fourth Clinical College of Peking University, Beijing, China
| | - Masao Akagi
- Department of Orthopaedic Surgery, Kinki University Faculty of Medicine, Osakasayama, Osaka, Japan
| | - T K Kim
- Joint Reconstruction Center, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Republic of Korea
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Sutter D, Fatuzzo CG, Moser S, Kim M, Fittipaldi R, Vecchione A, Granata V, Sassa Y, Cossalter F, Gatti G, Grioni M, Rønnow HM, Plumb NC, Matt CE, Shi M, Hoesch M, Kim TK, Chang TR, Jeng HT, Jozwiak C, Bostwick A, Rotenberg E, Georges A, Neupert T, Chang J. Hallmarks of Hunds coupling in the Mott insulator Ca 2RuO 4. Nat Commun 2017; 8:15176. [PMID: 28474681 PMCID: PMC5424259 DOI: 10.1038/ncomms15176] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [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: 10/07/2016] [Accepted: 03/03/2017] [Indexed: 11/20/2022] Open
Abstract
A paradigmatic case of multi-band Mott physics including spin-orbit and Hund's coupling is realized in Ca2RuO4. Progress in understanding the nature of this Mott insulating phase has been impeded by the lack of knowledge about the low-energy electronic structure. Here we provide—using angle-resolved photoemission electron spectroscopy—the band structure of the paramagnetic insulating phase of Ca2RuO4 and show how it features several distinct energy scales. Comparison to a simple analysis of atomic multiplets provides a quantitative estimate of the Hund's coupling J=0.4 eV. Furthermore, the experimental spectra are in good agreement with electronic structure calculations performed with Dynamical Mean-Field Theory. The crystal field stabilization of the dxy orbital due to c-axis contraction is shown to be essential to explain the insulating phase. These results underscore the importance of multi-band physics, Coulomb interaction and Hund's coupling that together generate the Mott insulating state of Ca2RuO4. Detailed knowledge of the low-energy electronic structure is required to understand the Mott insulating phase of Ca2RuO4. Here, Sutter et al. provide directly the experimental band structure of the paramagnetic insulating phase of Ca2RuO4 and unveil the electronic origin of its Mott phase.
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Affiliation(s)
- D Sutter
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, Zürich CH-8057, Switzerland
| | - C G Fatuzzo
- Institute of Physics, École Polytechnique Fedérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - S Moser
- Advanced Light Source (ALS), Berkeley, California 94720, USA
| | - M Kim
- College de France, Paris Cedex 05 75231, France.,Centre de Physique Théorique, Ecole Polytechnique, CNRS, Univ Paris-Saclay, Palaiseau 91128, France
| | - R Fittipaldi
- CNR-SPIN, Fisciano, Salerno I-84084, Italy.,Dipartimento di Fisica 'E.R. Caianiello', Università di Salerno, Fisciano, Salerno I-84084, Italy
| | - A Vecchione
- CNR-SPIN, Fisciano, Salerno I-84084, Italy.,Dipartimento di Fisica 'E.R. Caianiello', Università di Salerno, Fisciano, Salerno I-84084, Italy
| | - V Granata
- CNR-SPIN, Fisciano, Salerno I-84084, Italy.,Dipartimento di Fisica 'E.R. Caianiello', Università di Salerno, Fisciano, Salerno I-84084, Italy
| | - Y Sassa
- Department of Physics and Astronomy, Uppsala University, Uppsala S-75121, Sweden
| | - F Cossalter
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, Zürich CH-8057, Switzerland
| | - G Gatti
- Institute of Physics, École Polytechnique Fedérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - M Grioni
- Institute of Physics, École Polytechnique Fedérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - H M Rønnow
- Institute of Physics, École Polytechnique Fedérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - N C Plumb
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI CH-5232, Switzerland
| | - C E Matt
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI CH-5232, Switzerland
| | - M Shi
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI CH-5232, Switzerland
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - T-R Chang
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan.,Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - H-T Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan.,Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - C Jozwiak
- Advanced Light Source (ALS), Berkeley, California 94720, USA
| | - A Bostwick
- Advanced Light Source (ALS), Berkeley, California 94720, USA
| | - E Rotenberg
- Advanced Light Source (ALS), Berkeley, California 94720, USA
| | - A Georges
- College de France, Paris Cedex 05 75231, France.,Centre de Physique Théorique, Ecole Polytechnique, CNRS, Univ Paris-Saclay, Palaiseau 91128, France.,Department of Quantum Matter Physics, University of Geneva, Geneva 4 1211, Switzerland
| | - T Neupert
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, Zürich CH-8057, Switzerland
| | - J Chang
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, Zürich CH-8057, Switzerland
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39
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Kim J, Lee HH, Kang Y, Kim TK, Lee SW, So Y, Lee WW. Maximum standardised uptake value of quantitative bone SPECT/CT in patients with medial compartment osteoarthritis of the knee. Clin Radiol 2017; 72:580-589. [PMID: 28400059 DOI: 10.1016/j.crad.2017.03.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/08/2017] [Accepted: 03/14/2017] [Indexed: 11/16/2022]
Abstract
AIM To evaluate the correlation between the maximum standardised uptake value (SUVmax) from bone single-photon-emission computed tomography/computed tomography (SPECT/CT) and other imaging parameters for medial compartment osteoarthritis (OA) of the knee. MATERIALS AND METHODS Patients (n=26; male:female=2:24; age, 55.3±5.8 years) underwent quantitative knee SPECT/CT using technetium-99m (Tc-99m) hydroxymethylene diphosphonate (HDP) before surgical operation for medial OA of the knee. SUVmax was calculated using dedicated quantitative software. Visual grades of tracer uptake on bone SPECT/CT and Kellgren-Lawrence (KL) OA scores on plain radiographs were assessed using a five-point scale. Magnetic resonance imaging (MRI) scores (n=22) and patient symptom scores were also assessed. RESULTS The operated knees (n=34) had a greater SUVmax than the non-operated knees (n=18) in the medial compartment (14.1±6.1 versus 5.3±4.4, p<0.0001). In the medial compartment, the SUVmax was significantly correlated with SPECT/CT visual grades (rho=0.794, p<0.0001), KL scores (rho=0.703, p<0.0001), and MRI scores (rho=0.714-0.808, p≤0.0002); however, SUVmax and other imaging parameters were not correlated with patient symptom scores (p>0.05). CONCLUSIONS The SUVmax of quantitative bone SPECT/CT was highly correlated with traditional imaging parameters for medial compartment OA severity of the knee. Quantitative bone SPECT/CT is a promising imaging technique for the objective assessment of knee OA.
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Affiliation(s)
- J Kim
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - H-H Lee
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Y Kang
- Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - T K Kim
- Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - S W Lee
- Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Y So
- Department of Nuclear Medicine, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - W W Lee
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea; Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Republic of Korea.
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40
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Hoesch M, Kim TK, Dudin P, Wang H, Scott S, Harris P, Patel S, Matthews M, Hawkins D, Alcock SG, Richter T, Mudd JJ, Basham M, Pratt L, Leicester P, Longhi EC, Tamai A, Baumberger F. A facility for the analysis of the electronic structures of solids and their surfaces by synchrotron radiation photoelectron spectroscopy. Rev Sci Instrum 2017; 88:013106. [PMID: 28147670 DOI: 10.1063/1.4973562] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
A synchrotron radiation beamline in the photon energy range of 18-240 eV and an electron spectroscopy end station have been constructed at the 3 GeV Diamond Light Source storage ring. The instrument features a variable polarisation undulator, a high resolution monochromator, a re-focussing system to form a beam spot of 50 × 50 μm2, and an end station for angle-resolved photoelectron spectroscopy (ARPES) including a 6-degrees-of-freedom cryogenic sample manipulator. The beamline design and its performance allow for a highly productive and precise use of the ARPES technique at an energy resolution of 10-15 meV for fast k-space mapping studies with a photon flux up to 2 ⋅ 1013 ph/s and well below 3 meV for high resolution spectra.
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Affiliation(s)
- M Hoesch
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - T K Kim
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - P Dudin
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - H Wang
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - S Scott
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - P Harris
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - S Patel
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - M Matthews
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - D Hawkins
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - S G Alcock
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - T Richter
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - J J Mudd
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - M Basham
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - L Pratt
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - P Leicester
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - E C Longhi
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 ODE, United Kingdom
| | - A Tamai
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - F Baumberger
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
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41
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Kim TK, Moon BR, Kim T, Kim MK, Zoh KD. Degradation mechanisms of geosmin and 2-MIB during UV photolysis and UV/chlorine reactions. Chemosphere 2016; 162:157-164. [PMID: 27494316 DOI: 10.1016/j.chemosphere.2016.07.079] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/19/2016] [Accepted: 07/25/2016] [Indexed: 06/06/2023]
Abstract
We conducted chlorination, UV photolysis, and UV/chlorin reactions to investigate the intermediate formation and degradation mechanisms of geosmin and 2-methylisoborneol (2-MIB) in water. Chlorination hardly removed geosmin and 2-MIB, while the UV/chlorine reaction at 254 nm completely removed geosmin and 2-MIB within 40 min and 1 h, respectively, with lesser removals of both compounds during UV photolysis. The kinetics during both UV photolysis and UV/chlorine reactions followed a pseudo first-order reaction. Chloroform was found as a chlorinated intermediate during the UV/chlorine reaction of both geosmin and 2-MIB. The pH affected both the degradation and chloroform production during the UV/chlorine reaction. The open ring and dehydration intermediates identified during UV/chlorine reactions were 1,4-dimethyl-adamantane, and 1,3-dimethyl-adamantane from geosmin, 2-methylenebornane, and 2-methyl-2-bornene from 2-MIB, respectively. Additionally, 2-methyl-3-pentanol, 2,4-dimethyl-1-heptene, 4-methyl-2-heptanone, and 1,1-dichloro-2,4-dimethyl-1-heptane were newly identified intermediates from UV/chlorine reactions of both geosmin and 2-MIB. These intermediates were degraded as the reaction progressed. We proposed possible degradation pathways during the UV photolysis and UV/chlorine reactions of both compounds using the identified intermediates.
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Affiliation(s)
- Tae-Kyoung Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Bo-Ram Moon
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Taeyeon Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Moon-Kyung Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Kyung-Duk Zoh
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea.
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42
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Wang Z, McKeown Walker S, Tamai A, Wang Y, Ristic Z, Bruno FY, de la Torre A, Riccò S, Plumb NC, Shi M, Hlawenka P, Sánchez-Barriga J, Varykhalov A, Kim TK, Hoesch M, King PDC, Meevasana W, Diebold U, Mesot J, Moritz B, Devereaux TP, Radovic M, Baumberger F. Tailoring the nature and strength of electron-phonon interactions in the SrTiO3(001) 2D electron liquid. Nat Mater 2016; 15:835-839. [PMID: 27064529 DOI: 10.1038/nmat4623] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 03/10/2016] [Indexed: 06/05/2023]
Abstract
Surfaces and interfaces offer new possibilities for tailoring the many-body interactions that dominate the electrical and thermal properties of transition metal oxides. Here, we use the prototypical two-dimensional electron liquid (2DEL) at the SrTiO3(001) surface to reveal a remarkably complex evolution of electron-phonon coupling with the tunable carrier density of this system. At low density, where superconductivity is found in the analogous 2DEL at the LaAlO3/SrTiO3 interface, our angle-resolved photoemission data show replica bands separated by 100 meV from the main bands. This is a hallmark of a coherent polaronic liquid and implies long-range coupling to a single longitudinal optical phonon branch. In the overdoped regime the preferential coupling to this branch decreases and the 2DEL undergoes a crossover to a more conventional metallic state with weaker short-range electron-phonon interaction. These results place constraints on the theoretical description of superconductivity and allow a unified understanding of the transport properties in SrTiO3-based 2DELs.
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Affiliation(s)
- Z Wang
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - S McKeown Walker
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - A Tamai
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Y Wang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Z Ristic
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - F Y Bruno
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - A de la Torre
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - S Riccò
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - N C Plumb
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Shi
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - P Hlawenka
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY-II, 12489 Berlin, Germany
| | - J Sánchez-Barriga
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY-II, 12489 Berlin, Germany
| | - A Varykhalov
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY-II, 12489 Berlin, Germany
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - P D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - W Meevasana
- School of Physics and NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - U Diebold
- Institute of Applied Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, A-1040 Vienna, Austria
| | - J Mesot
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - B Moritz
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - T P Devereaux
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - M Radovic
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- SwissFEL, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - F Baumberger
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
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43
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Kim TK, Jung ES, Park JM, Kang K, Lee WW, Lee JJ. An Atypical Presentation of Subacute Encephalopathy with Seizures in Chronic Alcoholism Syndrome. J Epilepsy Res 2016; 6:28-30. [PMID: 27390677 PMCID: PMC4933678 DOI: 10.14581/jer.16005] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/12/2016] [Indexed: 11/04/2022] Open
Abstract
Subacute encephalopathy with seizures in chronic alcoholism syndrome is a rare clinical manifestation in patients with chronic alcohol abuse. We report the case of a patient with chronic alcoholism who presented with partial nonconvulsive status epilepticus associated with a thalamic lesion.
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Affiliation(s)
- Tae-Kyoung Kim
- Department of Neurology, Eulji General Hospital, Eulji University College of Medicine, Seoul, Korea
| | - Eui Sung Jung
- Department of Neurology, Eulji General Hospital, Eulji University College of Medicine, Seoul, Korea
| | - Jong-Moo Park
- Department of Neurology, Eulji General Hospital, Eulji University College of Medicine, Seoul, Korea
| | - Kyusik Kang
- Department of Neurology, Eulji General Hospital, Eulji University College of Medicine, Seoul, Korea
| | - Woong-Woo Lee
- Department of Neurology, Eulji General Hospital, Eulji University College of Medicine, Seoul, Korea
| | - Jung-Ju Lee
- Department of Neurology, Eulji General Hospital, Eulji University College of Medicine, Seoul, Korea
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44
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Lee W, Park HK, Lee DJ, Nam YU, Leem J, Kim TK. Design of a collective scattering system for small scale turbulence study in Korea Superconducting Tokamak Advanced Research. Rev Sci Instrum 2016; 87:043501. [PMID: 27131668 DOI: 10.1063/1.4944834] [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: 06/05/2023]
Abstract
The design characteristics of a multi-channel collective (or coherent) scattering system for small scale turbulence study in Korea Superconducting Tokamak Advanced Research (KSTAR), which is planned to be installed in 2017, are given in this paper. A few critical issues are discussed in depth such as the Faraday and Cotton-Mouton effects on the beam polarization, radial spatial resolution, probe beam frequency, polarization, and power. A proper and feasible optics with the 300 GHz probe beam, which was designed based on these issues, provides a simultaneous measurement of electron density fluctuations at four discrete poloidal wavenumbers up to 24 cm(-1). The upper limit corresponds to the normalized wavenumber kθρe of ∼0.15 in nominal KSTAR plasmas. To detect the scattered beam power and extract phase information, a quadrature detection system consisting of four-channel antenna/detector array and electronics will be employed.
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Affiliation(s)
- W Lee
- Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea
| | - H K Park
- Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea
| | - D J Lee
- Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea
| | - Y U Nam
- National Fusion Research Institute, Daejeon 34133, South Korea
| | - J Leem
- Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, South Korea
| | - T K Kim
- Kyunpook National University, Daegu 41566, South Korea
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45
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Oh CY, Kim DY, Jin SM, Kim TK, Kim JP, Jeong ED, Hyun MH, Sim EK, Lee YC, Jin JS. Self-Assembled Silica Nanostructures: Simultaneous Discrimination of Handedness, Pitch and Diameter of Helical Silica Nanotubes. J Nanosci Nanotechnol 2016; 16:1988-1992. [PMID: 27433714 DOI: 10.1166/jnn.2016.11956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The left- and right-handed helical silica nanostructures were obtained with the aid of organic templates, the formation of the nanostructures might follow a co-operation self-assembly mechanism. The chirality of the organogel self-assemblies was successfully transcribed in to the silica. The helical pitch and pore size of the silica nanotubes sensitively depended on the optical purity of the neutral gelator in the reaction mixtures.
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46
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Riley JM, Meevasana W, Bawden L, Asakawa M, Takayama T, Eknapakul T, Kim TK, Hoesch M, Mo SK, Takagi H, Sasagawa T, Bahramy MS, King PDC. Negative electronic compressibility and tunable spin splitting in WSe2. Nat Nanotechnol 2015; 10:1043-1047. [PMID: 26389661 DOI: 10.1038/nnano.2015.217] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 08/20/2015] [Indexed: 06/05/2023]
Abstract
Tunable bandgaps, extraordinarily large exciton-binding energies, strong light-matter coupling and a locking of the electron spin with layer and valley pseudospins have established transition-metal dichalcogenides (TMDs) as a unique class of two-dimensional (2D) semiconductors with wide-ranging practical applications. Using angle-resolved photoemission (ARPES), we show here that doping electrons at the surface of the prototypical strong spin-orbit TMD WSe2, akin to applying a gate voltage in a transistor-type device, induces a counterintuitive lowering of the surface chemical potential concomitant with the formation of a multivalley 2D electron gas (2DEG). These measurements provide a direct spectroscopic signature of negative electronic compressibility (NEC), a result of electron-electron interactions, which we find persists to carrier densities approximately three orders of magnitude higher than in typical semiconductor 2DEGs that exhibit this effect. An accompanying tunable spin splitting of the valence bands further reveals a complex interplay between single-particle band-structure evolution and many-body interactions in electrostatically doped TMDs. Understanding and exploiting this will open up new opportunities for advanced electronic and quantum-logic devices.
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Affiliation(s)
- J M Riley
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - W Meevasana
- School of Physics, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
- NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - L Bawden
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - M Asakawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - T Takayama
- Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033, Japan
- Max Planck Institute for Solid State Research, Stuttgart 70569, Germany
| | - T Eknapakul
- School of Physics, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - S-K Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley California 94720, USA
| | - H Takagi
- Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033, Japan
- Max Planck Institute for Solid State Research, Stuttgart 70569, Germany
| | - T Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - M S Bahramy
- Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - P D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
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47
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de la Torre A, McKeown Walker S, Bruno FY, Riccó S, Wang Z, Gutierrez Lezama I, Scheerer G, Giriat G, Jaccard D, Berthod C, Kim TK, Hoesch M, Hunter EC, Perry RS, Tamai A, Baumberger F. Collapse of the Mott Gap and Emergence of a Nodal Liquid in Lightly Doped Sr(2)IrO(4). Phys Rev Lett 2015; 115:176402. [PMID: 26551128 DOI: 10.1103/physrevlett.115.176402] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Indexed: 06/05/2023]
Abstract
We report angle resolved photoemission experiments on the electron doped Heisenberg antiferromagnet (Sr(1-x)La(x))(2)IrO(4). For a doping level of x=0.05, we find an unusual metallic state with coherent nodal excitations and an antinodal pseudogap bearing strong similarities with underdoped cuprates. This state emerges from a rapid collapse of the Mott gap with doping resulting in a large underlying Fermi surface that is backfolded by a (π,π) reciprocal lattice vector which we attribute to the intrinsic structural distortion of Sr(2)IrO(4).
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Affiliation(s)
- A de la Torre
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - S McKeown Walker
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - F Y Bruno
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - S Riccó
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Z Wang
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - I Gutierrez Lezama
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - G Scheerer
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - G Giriat
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - D Jaccard
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - C Berthod
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - E C Hunter
- School of Physics and Astronomy, The University of Edinburgh, James Clerk Maxwell Building, Mayfield Road, Edinburgh EH9 2TT, United Kingdom
| | - R S Perry
- London Centre for Nanotechnology and UCL Centre for Materials Discovery, University College London, London WC1E 6BT, United Kingdom
| | - A Tamai
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - F Baumberger
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife KY16 9SS, United Kingdom
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48
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Jiang J, Tang F, Pan XC, Liu HM, Niu XH, Wang YX, Xu DF, Yang HF, Xie BP, Song FQ, Dudin P, Kim TK, Hoesch M, Das PK, Vobornik I, Wan XG, Feng DL. Signature of Strong Spin-Orbital Coupling in the Large Nonsaturating Magnetoresistance Material WTe2. Phys Rev Lett 2015; 115:166601. [PMID: 26550888 DOI: 10.1103/physrevlett.115.166601] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Indexed: 06/05/2023]
Abstract
We report the detailed electronic structure of WTe2 by high resolution angle-resolved photoemission spectroscopy. We resolved a rather complicated Fermi surface of WTe2. Specifically, there are in total nine Fermi pockets, including one hole pocket at the Brillouin zone center Γ, and two hole pockets and two electron pockets on each side of Γ along the Γ-X direction. Remarkably, we have observed circular dichroism in our photoemission spectra, which suggests that the orbital angular momentum exhibits a rich texture at various sections of the Fermi surface. This is further confirmed by our density-functional-theory calculations, where the spin texture is qualitatively reproduced as the conjugate consequence of spin-orbital coupling. Since the spin texture would forbid backscatterings that are directly involved in the resistivity, our data suggest that the spin-orbit coupling and the related spin and orbital angular momentum textures may play an important role in the anomalously large magnetoresistance of WTe2. Furthermore, the large differences among spin textures calculated for magnetic fields along the in-plane and out-of-plane directions also provide a natural explanation of the large field-direction dependence on the magnetoresistance.
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Affiliation(s)
- J Jiang
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - F Tang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - X C Pan
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - H M Liu
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - X H Niu
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - Y X Wang
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - D F Xu
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - H F Yang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
| | - B P Xie
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - F Q Song
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - P Dudin
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - P Kumar Das
- CNR-IOM, TASC Laboratory AREA Science Park-Basovizza, 34149 Trieste, Italy
- International Centre for Theoretical Physics, Strada Costiera 11, 34100 Trieste, Italy
| | - I Vobornik
- CNR-IOM, TASC Laboratory AREA Science Park-Basovizza, 34149 Trieste, Italy
| | - X G Wan
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - D L Feng
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
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49
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Radulović ŽM, Porter LM, Kim TK, Bakshi M, Mulenga A. Amblyomma americanum tick saliva insulin-like growth factor binding protein-related protein 1 binds insulin but not insulin-like growth factors. Insect Mol Biol 2015; 24:539-550. [PMID: 26108887 PMCID: PMC4560673 DOI: 10.1111/imb.12180] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Silencing Amblyomma americanum insulin-like growth factor binding protein-related protein 1 (AamIGFBP-rP1) mRNA prevented ticks from feeding to repletion. In this study, we used recombinant (r)AamIGFBP-rP1 in a series of assays to obtain further insight into the role(s) of this protein in tick feeding regulation. Our results suggest that AamIGFBP-1 is an antigenic protein that is apparently exclusively expressed in salivary glands. We found that both males and females secrete AamIGFBP-rP1 into the host during feeding and confirmed that female ticks secrete this protein from within 24-48 h after attachment. Our data suggest that native AamIGFBP-rP1 is a functional insulin binding protein in that both yeast- and insect cell-expressed rAamIGFBP-rP1 bound insulin, but not insulin-like growth factors. When subjected to anti-blood clotting and platelet aggregation assays, rAamIGFBP-rP1 did not have any effect. Unlike human IGFBP-rP1, which is controlled by trypsinization, rAamIGFBP-rP1 is resistant to digestion, suggesting that the tick protein may not be under mammalian host control at the tick feeding site. The majority of tick-borne pathogens are transmitted 48 h after the tick has attached. Thus, the demonstrated antigenicity and secretion into the host within 24-48 h of the tick starting to feed makes AamIGFBP-rP1 an attractive target for antitick vaccine development.
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Affiliation(s)
- Ž M Radulović
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, USA
| | - L M Porter
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, USA
| | - T K Kim
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, USA
| | - M Bakshi
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, USA
| | - A Mulenga
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, USA
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50
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He Y, Chevillet JR, Liu G, Kim TK, Wang K. The effects of microRNA on the absorption, distribution, metabolism and excretion of drugs. Br J Pharmacol 2015; 172:2733-47. [PMID: 25296724 PMCID: PMC4439871 DOI: 10.1111/bph.12968] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 09/18/2014] [Accepted: 09/26/2014] [Indexed: 12/17/2022] Open
Abstract
The importance of genetic factors (e.g. sequence variation) in the absorption, distribution, metabolism, excretion (ADME) and overall efficacy of therapeutic agents is well established. Our ability to identify, interpret and utilize these factors is the subject of much clinical investigation and therapeutic development. However, drug ADME and efficacy are also heavily influenced by epigenetic factors such as DNA/histone methylation and non-coding RNAs [especially microRNAs (miRNAs)]. Results from studies using tools, such as in silico miRNA target prediction, in vitro functional assays, nucleic acid profiling/sequencing and high-throughput proteomics, are rapidly expanding our knowledge of these factors and their effects on drug metabolism. Although these studies reveal a complex regulation of drug ADME, an increased understanding of the molecular interplay between the genome, epigenome and transcriptome has the potential to provide practically useful strategies to facilitate drug development, optimize therapeutic efficacy, circumvent adverse effects, yield novel diagnostics and ultimately become an integral component of personalized medicine.
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Affiliation(s)
- Y He
- Institute of Medical Systems Biology, Guangdong Medical CollegeDongguan, Guangdong, China
| | | | - G Liu
- Department of Chemistry and Biochemistry, North Dakota State UniversityFargo, ND, USA
| | - T K Kim
- Institute for Systems BiologySeattle, WA, USA
| | - K Wang
- Institute for Systems BiologySeattle, WA, USA
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