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Lim SG, Kwon MS, Kim T, Kim H, Lee S, Lim J, Kim H, Lee KT. Correlation between the Cation Disorders of Fe 3+ and Li + in P3-Type Na 0.67[Li 0.1(Fe 0.5Mn 0.5) 0.9]O 2 for Sodium Ion Batteries. ACS Appl Mater Interfaces 2022; 14:33120-33129. [PMID: 35830246 DOI: 10.1021/acsami.2c05784] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Various Fe-based layered oxide materials have received attention as promising cathode materials for sodium ion batteries because of their low cost and high specific capacity. Only a few P3-type Fe-based oxide materials, however, have been examined as cathodes because the synthesis of highly crystalline P3-type Fe-based oxides is not facile. For this reason, the structural merits of the P3 structure are not yet fully understood. Herein, highly crystalline P3-type Na0.67[Li0.1(Fe0.5Mn0.5)0.9]O2 heated at 900 °C is introduced to improve the electrochemical performance of Fe-based layered oxides. The structures, reaction mechanisms, and electrochemical performances of P3 Na0.67[Li0.1(Fe0.5Mn0.5)0.9]O2, P2 Na0.57[Li0.1(Fe0.5Mn0.5)0.9]O2, and P2 Na0.67[Fe0.5Mn0.5]O2 are compared to demonstrate the roles of Li+ doping in the improved electrochemical performance of P3 Na0.67[Li0.1(Fe0.5Mn0.5)0.9]O2, such as stable capacity retention over 100 cycles. P3 Na0.67[Li0.1(Fe0.5Mn0.5)0.9]O2 significantly suppresses the migration of Fe3+ ions to tetrahedral sites in the Na layer during cycling because the cation disorder of Li+ is more favorable than that of Fe3+. As a result, P3 Na0.67[Li0.1(Fe0.5Mn0.5)0.9]O2 shows better cycle performance than P2 Na0.67[Fe0.5Mn0.5]O2. P3 Na0.67[Li0.1(Fe0.5Mn0.5)0.9]O2 also exhibits an improved rate performance compared to P2 Na0.67[Fe0.5Mn0.5]O2. This finding provides fundamental insights to improve the electrochemical performance of layered oxide cathode materials for sodium ion batteries.
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Affiliation(s)
- Shin Gwon Lim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Mi-Sook Kwon
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Taehun Kim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Hyeongi Kim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Suyeon Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Jungwoo Lim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Hanseul Kim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Kyu Tae Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
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Jung E, Park Y, Park K, Kwon MS, Park M, Sinha AK, Lee BH, Kim J, Lee HS, Chae SI, Cho SP, Lee KT, Hyeon T. Synthesis of nanostructured P2-Na 2/3MnO 2 for high performance sodium-ion batteries. Chem Commun (Camb) 2019; 55:4757-4760. [PMID: 30869098 DOI: 10.1039/c9cc01215j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a facile two-step method to synthesize nanostructured P2-Na2/3MnO2via ligand exchange and intercalation of sodium ions into ultrathin manganese oxide nanoplates. Sodium storage performance of the synthesized material shows a high capacity (170 mA h g-1) and an excellent rate performance.
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Affiliation(s)
- Euiyeon Jung
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Korea
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Kwon MS, Lim SG, Park Y, Lee SM, Chung KY, Shin TJ, Lee KT. P2 Orthorhombic Na 0.7[Mn 1-xLi x]O 2+y as Cathode Materials for Na-Ion Batteries. ACS Appl Mater Interfaces 2017; 9:14758-14768. [PMID: 28394115 DOI: 10.1021/acsami.7b00058] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
P2-type manganese-based oxide materials have received attention as promising cathode materials for sodium ion batteries because of their low cost and high capacity, but their reaction and failure mechanisms are not yet fully understood. In this study, the reaction and failure mechanisms of β-Na0.7[Mn1-xLix]O2+y (x = 0.02, 0.04, 0.07, and 0.25), α-Na0.7MnO2+y, and β-Na0.7MnO2+z are compared to clarify the dominant factors influencing their electrochemical performances. Using a quenching process with various amounts of a Li dopant, the Mn oxidation state in β-Na0.7[Mn1-xLix]O2+y is carefully controlled without the inclusion of impurities. Through various in situ and ex situ analyses including X-ray diffraction, X-ray absorption near-edge structure spectroscopy, and inductively coupled plasma mass spectrometry, we clarify the dependence of (i) reaction mechanisms on disordered Li distribution in the Mn layer, (ii) reversible capacities on the initial Mn oxidation state, (iii) redox potentials on the Jahn-Teller distortion, (iv) capacity fading on phase transitions during charging and discharging, and (v) electrochemical performance on Li dopant vs Mn vacancy. Finally, we demonstrate that the optimized β-Na0.7[Mn1-xLix]O2+y (x = 0.07) exhibits excellent electrochemical performance including a high reversible capacity of ∼183 mA h g-1 and stable cycle performance over 120 cycles.
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Affiliation(s)
- Mi-Sook Kwon
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University , 1, Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Shin Gwon Lim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University , 1, Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Yuwon Park
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University , 1, Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Sang-Min Lee
- Battery Research Center, Korea Electrotechnology Research Institute , 12 Bulmosan-ro 10 bean-gil, Changwon 51543, South Korea
| | - Kyung Yoon Chung
- Center for Energy Convergence Research, Korea Institute of Science and Technology , Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, South Korea
| | - Tae Joo Shin
- UNIST Central Research Facilities & School of Natural Science, Ulsan National Institute of Science and Technology , 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, South Korea
| | - Kyu Tae Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University , 1, Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
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Lee J, Lee Y, Lee J, Lee SM, Choi JH, Kim H, Kwon MS, Kang K, Lee KT, Choi NS. Ultraconcentrated Sodium Bis(fluorosulfonyl)imide-Based Electrolytes for High-Performance Sodium Metal Batteries. ACS Appl Mater Interfaces 2017; 9:3723-3732. [PMID: 28067499 DOI: 10.1021/acsami.6b14878] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present an ultraconcentrated electrolyte composed of 5 M sodium bis(fluorosulfonyl)imide in 1,2-dimethoxyethane for Na metal anodes coupled with high-voltage cathodes. Using this electrolyte, a very high Coulombic efficiency of 99.3% at the 120th cycle for Na plating/stripping is obtained in Na/stainless steel (SS) cells with highly reduced corrosivity toward Na metal and high oxidation durability (over 4.9 V versus Na/Na+) without corrosion of the aluminum cathode current collector. Importantly, the use of this ultraconcentrated electrolyte results in substantially improved rate capability in Na/SS cells and excellent cycling performance in Na/Na symmetric cells without the increase of polarization. Moreover, this ultraconcentrated electrolyte exhibits good compatibility with high-voltage Na4Fe3(PO4)2(P2O7) and Na0.7(Fe0.5Mn0.5)O2 cathodes charged to high voltages (>4.2 V versus Na/Na+), resulting in outstanding cycling stability (high reversible capacity of 109 mAh g-1 over 300 cycles for the Na/Na4Fe3(PO4)2(P2O7) cell) compared with the conventional dilute electrolyte, 1 M NaPF6 in ethylene carbonate/propylene carbonate (5/5, v/v).
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Affiliation(s)
- Jaegi Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , 50 UNIST-gil, Ulsan 44919, South Korea
| | - Yongwon Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , 50 UNIST-gil, Ulsan 44919, South Korea
| | - Jeongmin Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , 50 UNIST-gil, Ulsan 44919, South Korea
| | - Sang-Min Lee
- Battery Research Center, Korea Electrotechnology Research Institute , Changwon 642-120, South Korea
| | - Jeong-Hee Choi
- Battery Research Center, Korea Electrotechnology Research Institute , Changwon 642-120, South Korea
| | - Hyungsub Kim
- Department of Materials Science and Engineering, Seoul National University , Seoul 151-742, South Korea
| | - Mi-Sook Kwon
- Department of Chemical and Biological Engineering, Seoul National University , Seoul 151-742, South Korea
| | - Kisuk Kang
- Department of Materials Science and Engineering, Seoul National University , Seoul 151-742, South Korea
| | - Kyu Tae Lee
- Department of Chemical and Biological Engineering, Seoul National University , Seoul 151-742, South Korea
| | - Nam-Soon Choi
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , 50 UNIST-gil, Ulsan 44919, South Korea
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Kwon MS, Vorobyev V, Moe D, Parkkola R, Hämäläinen H. It takes brains to take risks. Eur J Public Health 2015. [DOI: 10.1093/eurpub/ckv167.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Jang JS, Lee KS, Lee EJ, Kwon MS, Kim TW. Enhancement of the Color Rendering Index of White Organic Light-Emitting Devices Based on a Blue and Red Emitting Layer with a Y3Al5O12:Ce3+ Green Phosphor Color-Conversion Layer. J Nanosci Nanotechnol 2015; 15:562-565. [PMID: 26328402 DOI: 10.1166/jnn.2015.8304] [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: 06/05/2023]
Abstract
White organic light-emitting devices (WOLEDs) were fabricated utilizing blue and red emitting organic light-emitting devices and a color conversion layer (CCL) made of yttrium aluminum garnet (YAG:Ce3+) phosphors embedded into polymethylmethacrylate. The good color balance for the color conversion of the WOLEDs was achieved utilizing 20-nm blue and 10-nm red OLEDs. The electroluminescence spectrum for the fabricated device showed a white color consisting of the blue color from the 4,4-bis(2,2-diphenylethen-1-yl)bipheny layer, the red color from the tris-(8-hydroxyquinolinato) aluminum: 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran layer, and the green color from the YAG:Ce3+ phosphor. The Commission Internationale de l'Eclairage coordinates of the WOLEDs slightly shifted from (0.25, 0.23) of the blue and red emission OLEDs without phosphors to (0.34, 0.35) of the OLEDs with green phosphors, indicative of the pure white color. WOLEDs with a CCL exhibited three wavelength white emissions with a color rendering index of 86.
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Kwon MS, Choi A, Park Y, Cheon JY, Kang H, Jo YN, Kim YJ, Hong SY, Joo SH, Yang C, Lee KT. Synthesis of ordered mesoporous phenanthrenequinone-carbon via π-π interaction-dependent vapor pressure for rechargeable batteries. Sci Rep 2014; 4:7404. [PMID: 25490893 PMCID: PMC4261180 DOI: 10.1038/srep07404] [Citation(s) in RCA: 27] [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: 09/26/2014] [Accepted: 11/19/2014] [Indexed: 11/23/2022] Open
Abstract
The π-π interaction-dependent vapour pressure of phenanthrenequinone can be used to synthesize a phenanthrenequinone-confined ordered mesoporous carbon. Intimate contact between the insulating phenanthrenequinone and the conductive carbon framework improves the electrical conductivity. This enables a more complete redox reaction take place. The confinement of the phenanthrenequinone in the mesoporous carbon mitigates the diffusion of the dissolved phenanthrenequinone out of the mesoporous carbon, and improves cycling performance.
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Affiliation(s)
- Mi-Sook Kwon
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulju-gun, Ulsan, 689-798, South Korea
| | - Aram Choi
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulju-gun, Ulsan, 689-798, South Korea
| | - Yuwon Park
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulju-gun, Ulsan, 689-798, South Korea
| | - Jae Yeong Cheon
- Department of Chemistry, Ulsan National Institute of Science and Technology, Ulju-gun, Ulsan, 689-798, South Korea
| | - Hyojin Kang
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulju-gun, Ulsan, 689-798, South Korea
| | - Yong Nam Jo
- Advanced Batteries Research Center, Korea Electronics Technology Institute, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-816, South Korea
| | - Young-Jun Kim
- Advanced Batteries Research Center, Korea Electronics Technology Institute, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-816, South Korea
| | - Sung You Hong
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulju-gun, Ulsan, 689-798, South Korea
| | - Sang Hoon Joo
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulju-gun, Ulsan, 689-798, South Korea
| | - Changduk Yang
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulju-gun, Ulsan, 689-798, South Korea
| | - Kyu Tae Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulju-gun, Ulsan, 689-798, South Korea
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Jeong HS, Kim SH, Lee KS, Jeong JM, Yoo TW, Kwon MS, Yoo KH, Kim TW. Optical properties of white organic light-emitting devices fabricated utilizing a mixed CaAl12O19:Mn4+ and Y3Al5O12:Ce3+ color conversion layer. J Nanosci Nanotechnol 2013; 13:4394-4397. [PMID: 23862509 DOI: 10.1166/jnn.2013.7003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
White organic light-emitting devices (OLEDs) were fabricated by combining a blue OLED with a color conversion layer made of mixed Y3Al5O12:Ce3+ green and Ca2AlO19:Mn4+ red phosphors. The X-ray diffraction patterns showed that Ce3+ ions in the Y3Al5O12:Ce3+ phosphors completely substituted for the Y3+ ions and the Mn4+ ions in the CaAl12O19:Mn4+ phosphors completely substituted for the Ca2+ ions. Electroluminescence spectra at 11 V for the OLEDs fabricated utilizing a color conversion layer showed that the Commission Internationale de l'Eclairage coordinates for the Y3Al5O12:Ce3+ and CaAl12O19:Mn4+ phosphors mixed at the ratio of 1:5 and 1:10 were (0.31, 0.34) and (0.32, 0.37), respectively, indicative of a good white color.
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Affiliation(s)
- H S Jeong
- Department Electronics and Computer Engineering, Hanyang University, Seoul 133-791, Korea
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Kwon WJ, Kim SH, Lee KS, Choo DC, Kim SW, Kim SW, Yoo TW, Kwon MS, Yoo KH, Kim TW. Color stability of white organic light emitting devices with a color conversion layer utilizing CdSe/ZnS quantum dots and phosphors dispersed in polymethylmethacrylate. J Nanosci Nanotechnol 2013; 13:4390-4393. [PMID: 23862508 DOI: 10.1166/jnn.2013.7002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
White organic light-emitting devices (WOLEDs) were fabricated by combining a blue emitting organic light-emitting devices (OLEDs) and a color conversion layer made of yttrium aluminum garnet phosphors and CdSe/ZnS quantum dots (QDs) embedded into polymethylmethacrylate. When the ratio of phosphors and QDs changed, a good color balance was achieved at a ratio of 1:5, and the maximum luminance of 18.21 cd/m2 was obtained. As the applied voltage varied from 12 to 16 V, Commission Internationale de l'Eclairage coordinates shifted only slightly from (0.32, 0.34) to (0.30, 0.33), indicating a good color stability.
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Affiliation(s)
- W J Kwon
- Department of Information Display Engineering, Hanyang University, Seoul 133-791, Korea
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Chung SY, Kim SK, Hong CW, Oh KW, Kim KT, Sul JG, Chung JW, Kwon MS. The time-dependent alteration of anti-diuretic hormone system in hindlimb unloaded rats. J Physiol Pharmacol 2012; 63:87-94. [PMID: 22460465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 01/31/2012] [Indexed: 05/31/2023]
Abstract
It is important to understand the mechanism on the fluid shift and volume regulation occurring in astronauts after spaceflight for future life in space. In the present study, we examined the time-dependent alteration of anti-diuretic hormone (ADH) concentrating on the water reabsorption system in hindlimb unloaded rats. Male Sprague-Dawley rats were hindlimb unloaded for 1 (HU1), 7(HU7), 14 days (HU14) or rested in the ground for 3 days after HU14 (HU14+3). The plasma ADH and angiotensin II level showed peak value at HU7, and the alterations were restored at HU14. However, several serum electrolytes (Na, K, Cl) were not changed regardless of HU period. In the immunohistochemical study, we examined that ADH and c-Fos immunoreactivities (IR) were maximized at HU7 in the paraventricular nucleus (PVN) and supraoptic nucleus (SON). Aquaporin 2 (AQP2) IR also was increased in the renal collecting duct for water re-absorption at HU7 showing a similar pattern with ADH. These results present a series of physiological ADH system alteration following to period of hindlimb unloading stimulus, indicating that ADH system is activated significantly at HU7. In addition, our results suggest that ADH system activation may be involved in anti-diuretic phenomenon in early spaceflight period. Furthermore, it is speculated that ADH system may require 14 days for adaptation to microgravity.
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Affiliation(s)
- S Y Chung
- Department of Pharmacology, School of Medicine, CHA University, Bundang-gu, Seongnam, Gyeonggi-do, South Korea
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Jeong HS, Kim SH, Bang HS, Choo DC, Kim TW, Hwang DH, Kwon MS, Chu C. Effects of the mixing ratio of the CaAl12O19:mn and Zn2SiO4:mn color-conversion layer on the color tunable emissions of white organic light-emitting devices. J Nanosci Nanotechnol 2012; 12:1654-1657. [PMID: 22630022 DOI: 10.1166/jnn.2012.4588] [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: 06/01/2023]
Abstract
The optical properties of white organic light-emitting devices (WOLEDs) fabricated utilizing a CaAl12O19:Mn and Zn2SiO4:Mn phosphor layer were investigated. X-ray diffraction patterns for CaAl12O19:Mn and Zn2SiO4:Mn phosphors showed that Mn ions in the CaAl12O19:Mn phosphors were completely substituted into Ca ions and that Mn ions in the Zn2SiO4:Mn phosphors were completely substituted into Zn ions. Field emission scanning electron microscopy images showed that the size of the CaAl12O19:Mn phosphor was approximately between 0.1 and 3 microm, and that the size of the Zn2SiO4:Mn phosphor was smaller than 7 microm. The color coordinates of the electroluminescence spectra for WOLEDs with phosphor thicknesses of 0.25 and 0.35 mm shifted to the white emission side because the generated blue light from the blue OLEDs combined with the red and green lights was converted by the CaAl12O19:Mn and the Zn2SiO4:Mn phosphor down-conversion layers.
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Affiliation(s)
- H S Jeong
- Department of Electronics and Computer Engineering, Hanyang University, Seoul 133-791, Korea
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Abstract
The baculovirus expression system has been used to produce large amounts of biologically active proteins by infecting insect cells with a recombinant baculovirus expressing the target protein. For an efficient expression of the target protein, it is necessary to infect insect cells with an adequate amount of virus. However, current methods are time-consuming and either have technical difficulties or are limited as a result of virus expression mechanism using a reporter gene. A novel method is developed to yield virus titers in 10 h that is easy to perform using 96-well plates and applicable to both any Autographa californica nucleopolyhyderovirus (AcNPV) and Bombyx mori nucleopolyhedrovirus (BmNPV)-based recombinant baculovirus. This assay uses an antibody to a DNA-binding protein to detect the infected cells via immunostaining. The titer is determined by counting foci produced as a result of infection of the virus under a fluorescent microscope. The required incubation period was shortened considerably because infected cells expressed viral antigens at the post-infection time of 4 h. Therefore, 10 h was enough to estimate the virus titer including virus infection time, insect cell culture, and estimation of virus titer. Titers determined using this immunological assay are comparable, both in value and validity, to those obtained using a traditional method, provided that the stocks have titers above 10(3) pfu/mL.
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Affiliation(s)
- M S Kwon
- Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka 422-8529, Japan
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Kim NH, Park SJ, Jin JK, Kwon MS, Choi EK, Carp RI, Kim YS. Increased ferric iron content and iron-induced oxidative stress in the brains of scrapie-infected mice. Brain Res 2000; 884:98-103. [PMID: 11082491 DOI: 10.1016/s0006-8993(00)02907-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Scrapie is a transmissible neurodegenerative disease of sheep and goats. The neuropathological changes include vacuolation, astrocytosis, the development of amyloid plaques in some instances, and neuronal loss. The mechanisms involved in neuronal cell death in scrapie are not known. Recently, we reported the presence of oxidative stress in the brains of scrapie-infected animals and suggested that this is the main mechanism that induces neuronal cell loss. It is known that oxidative stress induced by free radicals is associated with iron accumulation; this association led to an examination of the levels of iron (total iron, Fe(2+) and Fe(3+)) in the brains of control and scrapie-infected mice by biochemical methods. In the scrapie-infected group, both the level of total iron and the Fe(3+) level were significantly increased in cerebral cortex, striatum, and brainstem as compared to the values in the control group. A shift in the ratio of Fe(2+)/Fe(3+) was observed in the same regions of infected mice. Additionally, in this scrapie model, we confirmed the presence of oxidative stress, as evidenced by the increase of free malondialdehyde. These results suggest that iron metabolism is changed and that iron-induced oxidative stress partly contributes to neurodegeneration in scrapie infection.
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Affiliation(s)
- N H Kim
- Institute of Environment and Life Science, Hallym Academy of Sciences, 1 Ockcheon-Dong, Chuncheon, 200-702, Kangwon-Do, South Korea
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Lim JY, Shin CS, Chung EJ, Kim JS, Kim HU, Oh SJ, Choi WB, Ryou CS, Kim JB, Kwon MS, Chung TY, Song SI, Kim JK, Nahm BH, Hwang YS, Eun MY, Lee JS, Cheong JJ, Choi YD. Analysis of expressed sequence tags from Brassica rapa L. ssp. pekinensis. Mol Cells 2000; 10:399-404. [PMID: 10987136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Non-redundant expressed sequence tags (ESTs) were generated from six different organs at various developmental stages of Chinese cabbage, Brassica rapa L. ssp. pekinensis. Of the 1,295 ESTs, 915 (71%) showed significantly high homology in nucleotide or deduced amino acid sequences with other sequences deposited in databases, while 380 did not show similarity to any sequences. Briefly, 598 ESTs matched with proteins of identified biological function, 177 with hypothetical proteins or non-annotated Arabidopsis genome sequences, and 140 with other ESTs. About 82% of the top-scored matching sequences were from Arabidopsis or Brassica, but overall 558 (43%) ESTs matched with Arabidopsis ESTs at the nucleotide sequence level. This observation strongly supports the idea that gene-expression profiles of Chinese cabbage differ from that of Arabidopsis, despite their genome structures being similar to each other. Moreover, sequence analyses of 21 Brassica ESTs revealed that their primary structure is different from those of corresponding annotated sequences of Arabidopsis genes. Our data suggest that direct prediction of Brassica gene expression pattern based on the information from Arabidopsis genome research has some limitations. Thus, information obtained from the Brassica EST study is useful not only for understanding of unique developmental processes of the plant, but also for the study of Arabidopsis genome structure.
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Affiliation(s)
- J Y Lim
- School of Agricultural Biotechnology, Seoul National University, Suwon, Korea
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Kwon MS, Park CS, Choi K, Ahnn J, Kim JI, Eom SH, Kaufman SJ, Song WK. Calreticulin couples calcium release and calcium influx in integrin-mediated calcium signaling. Mol Biol Cell 2000; 11:1433-43. [PMID: 10749940 PMCID: PMC14857 DOI: 10.1091/mbc.11.4.1433] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The engagement of integrin alpha7 in E63 skeletal muscle cells by laminin or anti-alpha7 antibodies triggered transient elevations in the intracellular free Ca(2+) concentration that resulted from both inositol triphosphate-evoked Ca(2+) release from intracellular stores and extracellular Ca(2+) influx through voltage-gated, L-type Ca(2+) channels. The extracellular domain of integrin alpha7 was found to associate with both ectocalreticulin and dihydropyridine receptor on the cell surface. Calreticulin appears to also associate with cytoplasmic domain of integrin alpha7 in a manner highly dependent on the cytosolic Ca(2+) concentration. It appeared that intracellular Ca(2+) release was a prerequisite for Ca(2+) influx and that calreticulin associated with the integrin cytoplasmic domain mediated the coupling of between the Ca(2+) release and Ca(2+) influx. These findings suggest that calreticulin serves as a cytosolic activator of integrin and a signal transducer between integrins and Ca(2+) channels on the cell surface.
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Affiliation(s)
- M S Kwon
- Department of Life Science, Kwangju Institute of Science and Technology, Kwangju 500-712, Korea
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Kim HC, Jhoo WK, Ko KH, Kim WK, Bing G, Kwon MS, Shin EJ, Suh JH, Lee YG, Lee DW. Prolonged exposure to cigarette smoke blocks the neurotoxicity induced by kainic acid in rats. Life Sci 2000; 66:317-26. [PMID: 10665983 DOI: 10.1016/s0024-3205(99)00593-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We examined the effects of cigarette smoke (CS) on three parameters associated with kainic acid (KA)-induced neurotoxicity: seizure activity, cell loss in the hippocampus, and increased Fos-related antigen (FRA) expression. Animals were exposed to the main stream of CS from 15 Kentucky 2R1F research cigarettes containing 28.6 mg tar and 1.74 mg nicotine per cigarette, for 10 min a day, 6 days per week, for 4 weeks, using an automatic smoking machine. KA administration (10 mg/kg, i.p.) produced robust behavioral convulsions lasting 4-5 h. Pre-exposure to CS significantly reduced the seizures, mortality, and severe loss of cells in regions CA1 and CA3 of the hippocampus after KA administration. Consistently, pre-exposure to CS significantly attenuated the KA-induced increased FRA immunoreactivity in the hippocampus. In contrast, pretreatment with central nicotinic antagonist, mecamylamine (2 or 10 mg/kg, i.p.) blocked the neuroprotective effects mediated by CS in a dose-dependent manner. These results indicate that CS exposure provides neuroprotection against the KA insult via nicotinic receptor activation.
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Affiliation(s)
- H C Kim
- Department of Pharmacy, College of Pharmacy, Kangwon National University, Korea Institute of Drug Abuse, Chunchon.
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Abstract
We report a case of pseudomembranous necrotizing bronchial aspergillosis in a patient with acute myelocytic leukaemia who died of massive haemoptysis. Lobar collapse was demonstrated on chest radiography. CT showed a marked necrotic thickening of the lobar bronchus with extension of the disease in to the peribronchial region.
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Affiliation(s)
- M I Ahn
- Department of Radiology, St Vincent's Hospital, College of Medicine, Catholic University of Korea, Seoul, Korea
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Jung SL, Choi KH, Park YH, Song HC, Kwon MS. Cemento-ossifying fibroma presenting as a mass of the parapharyngeal and masticator space. AJNR Am J Neuroradiol 1999; 20:1744-6. [PMID: 10543652 PMCID: PMC7056173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
We report a case of cemento-ossifying fibroma that presented as a large extraosseous mass in the masticator and parapharyngeal space. CT scanning and MR imaging showed a large extraosseous mass with central conglomerated, well-matured ossified nodules and fatty marrow. The central matured ossified nodules were of low density on CT scans and high signal intensity on T1- and T2-weighted MR images. Multiplanar reformatted CT scans revealed the origin of the mass to be at the extraction site of the right lower second molar tooth.
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Affiliation(s)
- S L Jung
- Department of Radiology, The Catholic University of Korea, Suwon, Kyunggi-do, Korea (south)
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Ibim SE, Ambrosio AM, Kwon MS, El-Amin SF, Allcock HR, Laurencin CT. Novel polyphosphazene/poly(lactide-co-glycolide) blends: miscibility and degradation studies. Biomaterials 1997; 18:1565-9. [PMID: 9430340 DOI: 10.1016/s0142-9612(97)80009-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A novel biodegradable polymer blend was developed for potential biomedical applications. A 50:50 poly(lactide-co-glycolide) (PLAGA) was blended in a 50:50 ratio with the followiing polyphosphazenes (PPHOS): poly[(25% ethyl glycinato)(75% p-methylphenoxy)phosphazene[, poly[(50% ethyl glycinato)(50% p-methylphenoxy)phosphazene], and poly[(75% ethyl glycinato)(25% p-methylphenoxy)phosphazene] to obtain Blends A, B, and C, respectively, using a mutual solvent technique. The miscibility of these blends was determined by measuring their glass transition temperature (Tg) using differential scanning calorimetry. After fabrication using a casting technique, the degradation of the matrices was examined. Differential scanning calorimetry showed one glass transition temperature for each blend which was between the Tg's of their respective parent polymers indicating miscibility of the blends. Surface analysis by scanning electron microscopy showed the matrices to have smooth uniform surfaces. Degradation studies showed near-zero order degradation kinetics for the blends with Blends A and B losing 10% of their mass after two weeks and Blend C degrading more rapidly (30% mass loss during the same period). These findings suggest that these novel biodegradable PLAGA/PPHOS blends may be useful for biomedical purposes.
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Affiliation(s)
- S E Ibim
- Department of Biology, Morris Brown College, Atlanta, GA, USA
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Ho L, Javed AA, Pepin RA, Thekkumkara TJ, Raefsky C, Mole JE, Caliendo AM, Kwon MS, Kerr DS, Patel MS. Identification of a cDNA clone for the beta-subunit of the pyruvate dehydrogenase component of human pyruvate dehydrogenase complex. Biochem Biophys Res Commun 1988; 150:904-8. [PMID: 2829898 DOI: 10.1016/0006-291x(88)90714-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We report the isolation of a 1.5 kb cDNA clone for the beta subunit of human pyruvate dehydrogenase (E1) from a human liver lambda gt11 cDNA library using anti-E1 serum. We generated a peptide sequence of 24 amino acids starting from the N-terminus of bovine heart mature E1 beta. The identity of the E1 beta cDNA clone was confirmed by the similarity between the amino acid sequence deduced from the cDNA nucleotide sequence and the known amino acid sequence of bovine heart E1 beta. In Northern analysis of total RNA extracted from human heart, the E1 beta cDNA clone hybridized to a major 1.6 kb and a minor 5.2 kb RNA species.
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Affiliation(s)
- L Ho
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH 44106
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