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Moon H, Sultana T, Lee J, Huh J, Lee HD, Choi MS. Biomimetic lipid-fluorescein probe for cellular bioimaging. Front Chem 2023; 11:1151526. [PMID: 37153532 PMCID: PMC10160471 DOI: 10.3389/fchem.2023.1151526] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 04/10/2023] [Indexed: 05/09/2023] Open
Abstract
Fluorescence probe is one of the most powerful tools for cellular imaging. Here, three phospholipid-mimicking fluorescent probes (FP1-FP3) comprising fluorescein and two lipophilic groups of saturated and/or unsaturated C18 fatty acids were synthesized, and their optical properties were investigated. Like in biological phospholipids, the fluorescein group acts as a hydrophilic polar headgroup and the lipid groups act as hydrophobic non-polar tail groups. Laser confocal microscope images illustrated that FP3, which contains both saturated and unsaturated lipid tails, showed great uptake into the canine adipose-derived mesenchymal stem cells.
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Affiliation(s)
- Hyungkyu Moon
- Department of Materials Chemistry and Engineering, Konkuk University, Seoul, Republic of Korea
| | - Tania Sultana
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science and Technology, Konkuk University, Seoul, Republic of Korea
| | - JeongIk Lee
- Department of Veterinary Obstetrics and Theriogenology, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea
- *Correspondence: Myung-Seok Choi, ; JeongIk Lee,
| | - Jungrim Huh
- Social Eco-Tech Research Institute, Konkuk University, Seoul, Republic of Korea
| | - Hae Dong Lee
- Department of Materials Chemistry and Engineering, Konkuk University, Seoul, Republic of Korea
| | - Myung-Seok Choi
- Department of Materials Chemistry and Engineering, Konkuk University, Seoul, Republic of Korea
- *Correspondence: Myung-Seok Choi, ; JeongIk Lee,
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Cho EJ, Kang MR, Kim JH, Lee JI, Son ES, Park CH, Aung WW, Lee JS. Evaluation of the MolecuTech ® REBA MTB-XMDR kit for detection of pre-extensively drug-resistant TB. Int J Tuberc Lung Dis 2022; 26:869-874. [PMID: 35996285 DOI: 10.5588/ijtld.21.0606] [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: 11/10/2022] Open
Abstract
BACKGROUND: Rapid diagnosis of drug-resistant TB is critical for early initiation of effective therapy. YD Diagnostics in South Korea recently developed the MolecuTech® REBA MTB-XMDR test to rapidly detect multidrug-resistant TB (MDR-TB), pre-extensively drug-resistant TB (pre-XDR-TB) and resistance to second-line injectable drugs (SLIDs) simultaneously using a fully automated test platform. This study aimed to evaluate the MolecuTech® test for the detection of MDR- and pre-XDR-TB, as well as SLID resistance.METHODS: A total of 151 clinical Mycobacterium tuberculosis isolates from South Korea were tested using the MolecuTech test, and the results were analysed by comparing these with phenotypic drug susceptibility testing (pDST) and sequencing.RESULTS: Compared to pDST, the MolecuTech test showed a sensitivity and specificity of respectively 97.7% and 100.0% for rifampicin (RIF), 82.4% and 100.0% for isoniazid (INH), 97.5% and 97.2% for fluoroquinolones (FQs), and 94.0% and 98.8% for SLIDs. Concordances with the sequencing results of each resistance determinant were 99.3% for RIF, 96.7% for INH, 98.7% for FQs and 99.3% for SLIDs.CONCLUSION: The MolecuTech test is an efficient and reliable rapid molecular diagnostic tool for the simultaneous screening of MDR- and pre-XDR-TB.
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Affiliation(s)
- E J Cho
- International Tuberculosis Research Center, Gyeongsangnam-do, College of Health Sciences, Catholic University of Pusan, Busan, Republic of Korea
| | - M R Kang
- YD Diagnostics, Gyeonggi-do, College of Health Sciences, Catholic University of Pusan, Busan, Republic of Korea
| | - J H Kim
- YD Diagnostics, Gyeonggi-do, College of Health Sciences, Catholic University of Pusan, Busan, Republic of Korea, Department of Clinical Laboratory Science, College of Health Sciences, Catholic University of Pusan, Busan, Republic of Korea
| | - J I Lee
- International Tuberculosis Research Center, Gyeongsangnam-do, College of Health Sciences, Catholic University of Pusan, Busan, Republic of Korea
| | - E S Son
- International Tuberculosis Research Center, Gyeongsangnam-do, College of Health Sciences, Catholic University of Pusan, Busan, Republic of Korea
| | - C H Park
- YD Diagnostics, Gyeonggi-do, College of Health Sciences, Catholic University of Pusan, Busan, Republic of Korea, College of Pharmacy, Dongguk University, Seoul, Republic of Korea
| | - W W Aung
- Advanced Molecular Research Centre, Department of Medical Research, Yangon, Myanmar
| | - J S Lee
- International Tuberculosis Research Center, Gyeongsangnam-do, College of Health Sciences, Catholic University of Pusan, Busan, Republic of Korea
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Cho H, Song J, Shin JW, Moon J, Kwon BH, Lee JI, Yoo S, Cho NS. Identification of a multi-stack structure of graphene electrodes doped layer-by-layer with benzimidazole and its implication for the design of optoelectronic devices. Opt Express 2021; 29:23131-23141. [PMID: 34614583 DOI: 10.1364/oe.430149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/27/2021] [Indexed: 06/13/2023]
Abstract
Optical properties of benzimidazole (BI)-doped layer-by-layer graphene differ significantly from those of intrinsic graphene. Our study based on transmission electron microscopy and X-ray photoelectron spectroscopy depth profiling reveals that such a difference stems from its peculiar stratified geometry formed in situ during the doping process. This work presents an effective thickness and optical constants that can treat these multi-stacked BI-doped graphene electrodes as a single equivalent medium. For verification, the efficiency and angular emission spectra of organic light-emitting diodes with the BI-doped graphene electrode are modeled with the proposed method, and we demonstrate that the calculation matches experimental results in a much narrower margin than that based on the optical properties of undoped graphene.
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Kim JY, Cheon S, Kim DK, Nam S, Han J, Hwang CS, Piao Y, Lee JI. Solvent-assisted strongly enhanced light-emitting electrochemiluminescent devices for lighting applications. RSC Adv 2021; 11:4682-4687. [PMID: 35424409 PMCID: PMC8694504 DOI: 10.1039/d0ra10525b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 01/15/2021] [Indexed: 11/21/2022] Open
Abstract
Rubrene-based electrochemiluminescence (r-ECL) cells with two different solvent systems is prepared, one in a co-solvent system with a mixture of 1,2-dichlorobenzene and propylene carbonate (DCB : PC, v/v 3 : 1) and another in a single solvent system of tetrahydrofuran (THF), as the medium to form a liquid-electrolyte (L-El). By simply changing the solvent systems, from the co-solvent DCB : PC (v/v 3 : 1) to the single solvent THF, with the same amount of electrochemiluminescent rubrene (5 mM) and Li-based salt, a dramatically enhanced brightness of over 30 cd m−2 is observed for the r-ECL cell in L-ElTHF which is approximately 7-times higher than the brightness of 5 cd m−2 observed for the r-ECL in L-ElDCB:PC(v/v 3:1). Simple and easily preparable electrochemiluminescent device (ECLD) is a promising alternative to LED and/or OLED for lighting application.![]()
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Affiliation(s)
- Joo Yeon Kim
- Reality Display Research Lab
- Reality Device Research Division
- Electronics and Telecommunications Research Institute (ETRI)
- 34129 Daejeon
- Korea
| | - Sanghoon Cheon
- Reality Display Research Lab
- Reality Device Research Division
- Electronics and Telecommunications Research Institute (ETRI)
- 34129 Daejeon
- Korea
| | - Dae Kyom Kim
- Program in Nano Science and Technology
- Graduate School of Convergence Science and Technology
- Seoul National University
- 16229 Suwon-si
- Korea
| | - Sooji Nam
- Flexible Electronic Device Research Lab
- Electronics and Telecommunications Research Institute (ETRI)
- 34129 Daejeon
- Korea
| | - Jisu Han
- ICT-Advanced Device Technology
- University of Science and Technology
- Daejeon 34113
- Republic of Korea
| | - Chi-Sun Hwang
- Reality Display Research Lab
- Reality Device Research Division
- Electronics and Telecommunications Research Institute (ETRI)
- 34129 Daejeon
- Korea
| | - Yuanzhe Piao
- Program in Nano Science and Technology
- Graduate School of Convergence Science and Technology
- Seoul National University
- 16229 Suwon-si
- Korea
| | - Jeong-Ik Lee
- Reality Device Research Division
- Electronics and Telecommunications Research Institute (ETRI)
- 34129 Daejeon
- Korea
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Cho YJ, Choi SH, Lee R, Hwang H, Rhim H, Cho IH, Kim HC, Lee JI, Hwang SH, Nah SY. Ginseng Gintonin Contains Ligands for GPR40 and GPR55. Molecules 2020; 25:molecules25051102. [PMID: 32121640 PMCID: PMC7179172 DOI: 10.3390/molecules25051102] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/17/2020] [Accepted: 02/25/2020] [Indexed: 02/06/2023] Open
Abstract
Gintonin, a novel ginseng-derived glycolipoprotein complex, has an exogenous ligand for lysophosphatidic acid (LPA) receptors. However, recent lipid analysis of gintonin has shown that gintonin also contains other bioactive lipids besides LPAs, including linoleic acid and lysophosphatidylinositol (LPI). Linoleic acid, a free fatty acid, and LPI are known as ligands for the G-protein coupled receptors (GPCR), GPR40, and GPR55, respectively. We, herein, investigated whether gintonin could serve as a ligand for GPR40 and GPR55, using the insulin-secreting beta cell-derived cell line INS-1 and the human prostate cancer cell line PC-3, respectively. Gintonin dose-dependently enhanced insulin secretion from INS-1 cells. Gintonin-stimulated insulin secretion was partially inhibited by a GPR40 receptor antagonist but not an LPA1/3 receptor antagonist and was down-regulated by small interfering RNA (siRNA) against GPR40. Gintonin dose-dependently induced [Ca2+]i transients and Ca2+-dependent cell migration in PC-3 cells. Gintonin actions in PC-3 cells were attenuated by pretreatment with a GPR55 antagonist and an LPA1/3 receptor antagonist or by down-regulating GPR55 with siRNA. Taken together, these results demonstrated that gintonin-mediated insulin secretion by INS-1 cells and PC-3 cell migration were regulated by the respective activation of GPR40 and GPR55 receptors. These findings indicated that gintonin could function as a ligand for both receptors. Finally, we demonstrated that gintonin contained two more GPCR ligands, in addition to that for LPA receptors. Gintonin, with its multiple GPCR ligands, might provide the molecular basis for the multiple pharmacological actions of ginseng.
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Affiliation(s)
- Yeon-Jin Cho
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (Y.-J.C.); (S.-H.C.); (R.L.)
| | - Sun-Hye Choi
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (Y.-J.C.); (S.-H.C.); (R.L.)
| | - Rami Lee
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (Y.-J.C.); (S.-H.C.); (R.L.)
| | - Hongik Hwang
- Center for Neuroscience, Korea Institute of Science and Technology, Seoul 02792, Korea; (H.H.); (H.R.)
| | - Hyewhon Rhim
- Center for Neuroscience, Korea Institute of Science and Technology, Seoul 02792, Korea; (H.H.); (H.R.)
| | - Ik-Hyun Cho
- Department of Convergence Medical Science, Department of Science in Korean Medicine and Brain Korea 21 Plus Program, Graduate School, Kyung Hee University, Seoul 02447, Korea;
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology program, College of Pharmacy, Kangwon National University, Chunchon 24341, Korea;
| | - Jeong-Ik Lee
- Department of Veterinary Obstetrics and Theriogenology, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea;
| | - Sung-Hee Hwang
- Department of Pharmaceutical Engineering, College of Health Sciences, Sangji University, Wonju 26339, Korea
- Correspondence: (S.-H.H.); (S.-Y.N.); Tel.: +82-33-738-7922 (S.-H.H.); +82-2-450-4154 (S.-Y.N.)
| | - Seung-Yeol Nah
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (Y.-J.C.); (S.-H.C.); (R.L.)
- Correspondence: (S.-H.H.); (S.-Y.N.); Tel.: +82-33-738-7922 (S.-H.H.); +82-2-450-4154 (S.-Y.N.)
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Lee B, Oh JY, Cho H, Joo CW, Yoon H, Jeong S, Oh E, Byun J, Kim H, Lee S, Seo J, Park CW, Choi S, Park NM, Kang SY, Hwang CS, Ahn SD, Lee JI, Hong Y. Ultraflexible and transparent electroluminescent skin for real-time and super-resolution imaging of pressure distribution. Nat Commun 2020; 11:663. [PMID: 32005935 PMCID: PMC6994701 DOI: 10.1038/s41467-020-14485-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 01/03/2020] [Indexed: 11/16/2022] Open
Abstract
The ability to image pressure distribution over complex three-dimensional surfaces would significantly augment the potential applications of electronic skin. However, existing methods show poor spatial and temporal fidelity due to their limited pixel density, low sensitivity, or low conformability. Here, we report an ultraflexible and transparent electroluminescent skin that autonomously displays super-resolution images of pressure distribution in real time. The device comprises a transparent pressure-sensing film with a solution-processable cellulose/nanowire nanohybrid network featuring ultrahigh sensor sensitivity (>5000 kPa-1) and a fast response time (<1 ms), and a quantum dot-based electroluminescent film. The two ultrathin films conform to each contact object and transduce spatial pressure into conductivity distribution in a continuous domain, resulting in super-resolution (>1000 dpi) pressure imaging without the need for pixel structures. Our approach provides a new framework for visualizing accurate stimulus distribution with potential applications in skin prosthesis, robotics, and advanced human-machine interfaces.
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Affiliation(s)
- Byeongmoon Lee
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Ji-Young Oh
- Reality Device Research Division, ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI), Daejeon, 34129, Republic of Korea.
| | - Hyeon Cho
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Chul Woong Joo
- Reality Device Research Division, ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI), Daejeon, 34129, Republic of Korea
| | - Hyungsoo Yoon
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Sujin Jeong
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Eunho Oh
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Junghwan Byun
- Department of Mechanical and Aerospace Engineering, Institute of Advanced Machines and Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- Soft Robotics Research Center (SRRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Hanul Kim
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Seunghwan Lee
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Jiseok Seo
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Chan Woo Park
- Reality Device Research Division, ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI), Daejeon, 34129, Republic of Korea
| | - Sukyung Choi
- Reality Device Research Division, ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI), Daejeon, 34129, Republic of Korea
| | - Nae-Man Park
- Reality Device Research Division, ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI), Daejeon, 34129, Republic of Korea
| | - Seung-Youl Kang
- Reality Device Research Division, ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI), Daejeon, 34129, Republic of Korea
| | - Chi-Sun Hwang
- Reality Device Research Division, ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI), Daejeon, 34129, Republic of Korea
| | - Seong-Deok Ahn
- Reality Device Research Division, ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI), Daejeon, 34129, Republic of Korea
| | - Jeong-Ik Lee
- Reality Device Research Division, ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI), Daejeon, 34129, Republic of Korea
| | - Yongtaek Hong
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center (ISRC), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
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Moon J, Cho H, Maeng MJ, Choi K, Nguyen ĐT, Han JH, Shin JW, Kwon BH, Lee J, Cho S, Lee JI, Park Y, Lee JS, Cho NS. Mechanistic Understanding of Improved Performance of Graphene Cathode Inverted Organic Light-Emitting Diodes by Photoemission and Impedance Spectroscopy. ACS Appl Mater Interfaces 2018; 10:26456-26464. [PMID: 30010310 DOI: 10.1021/acsami.8b07751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Modification of multilayer graphene films was investigated for a cathode of organic light-emitting diodes (OLEDs). By doping the graphene/electron transport layer (ETL) interface with Li, the driving voltage of the OLED was reduced dramatically from 24.5 to 3.2 V at a luminance of 1000 cd/m2. The external quantum efficiency was also enhanced from 3.4 to 12.9%. Surface analyses showed that the Li doping significantly lowers the lowest unoccupied molecular orbital level of the ETL, thereby reducing the electron injection barrier and facilitating electron injection from the cathode. Impedance spectroscopy analyses performed on electron-only devices (EODs) revealed the existence of distributed trap states with a well-defined activation energy, which is successfully described by the Havriliak-Negami capacitance functions and the temperature-independent frequency dispersion parameters. In particular, the graphene EOD showed a unique high-frequency feature as compared to the indium tin oxide one, which could be explained by an additional parallel capacitance element.
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Affiliation(s)
- Jaehyun Moon
- Reality Device Research Division , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
| | - Hyunsu Cho
- Reality Device Research Division , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
| | - Min-Jae Maeng
- Department of Physics and Research Institute for Basic Sciences , Kyung Hee University , Seoul 02447 , Republic of Korea
| | - Kwangmin Choi
- Department of Physics and Research Institute for Basic Sciences , Kyung Hee University , Seoul 02447 , Republic of Korea
| | - Đăng Thành Nguyen
- School of Materials Science and Engineering , Chonnam National University , Gwangju 61186 , Republic of Korea
| | - Jun-Han Han
- Reality Device Research Division , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
| | - Jin-Wook Shin
- Reality Device Research Division , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
| | - Byoung-Hwa Kwon
- Reality Device Research Division , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
| | - Jonghee Lee
- Reality Device Research Division , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
- Department of Creative Convergence Engineering , Hanbat National University , Daejeon 34158 , Republic of Korea
| | - Seungmin Cho
- Hanwha Techwin R&D Center , Seongnam 13488 , Republic of Korea
| | - Jeong-Ik Lee
- Reality Device Research Division , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
| | - Yongsup Park
- Department of Physics and Research Institute for Basic Sciences , Kyung Hee University , Seoul 02447 , Republic of Korea
| | - Jong-Sook Lee
- School of Materials Science and Engineering , Chonnam National University , Gwangju 61186 , Republic of Korea
| | - Nam Sung Cho
- Reality Device Research Division , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
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Han KH, Park YS, Cho DH, Han Y, Lee J, Yu B, Cho NS, Lee JI, Kim JJ. Optical Analysis of Power Distribution in Top-Emitting Organic Light Emitting Diodes Integrated with Nanolens Array Using Finite Difference Time Domain. ACS Appl Mater Interfaces 2018; 10:18942-18947. [PMID: 29749737 DOI: 10.1021/acsami.8b02631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Recently, we have addressed that a formation mechanism of a nanolens array (NLA) fabricated by using a maskless vacuum deposition is explained as the increase in surface tension of organic molecules induced by their crystallization. Here, as another research using finite difference time domain simulations, not electric field intensities but transmitted energies of electromagnetic waves inside and outside top-emitting blue organic light-emitting diodes (TOLEDs), without and with NLAs, are obtained, to easily grasp the effect of NLA formation on the light extraction of TOLEDs. Interestingly, the calculations show that NLA acts as an efficient light extraction structure. With NLA, larger transmitted energies in the direction from emitting layer to air are observed, indicating that NLAs send more light to air otherwise trapped in the devices by reducing the losses by waveguide and absorption. This is more significant for higher refractive index of NLA. Simulation and measurement results are consistent. A successful increase in both light extraction efficiency and color stability of blue TOLEDs, rarely reported before, is accomplished by introducing the highly process-compatible NLA technology using the one-step dry process. Blue TOLEDs integrated with a N, N'-di(1-naphthyl)- N, N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine NLA with a refractive index of 1.8 show a 1.55-times-higher light extraction efficiency, compared to those without it. In addition, viewing angle characteristics are enhanced and image blurring is reduced, indicating that the manufacturer-adaptable technology satisfies the requirements of highly efficient and color-stable top-emission displays.
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Affiliation(s)
- Kyung-Hoon Han
- Department of Materials Science and Engineering , Seoul National University , Seoul 08826 , Republic of Korea
| | - Young-Sam Park
- Flexible Information Device Research Section , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
| | - Doo-Hee Cho
- Flexible Information Device Research Section , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
| | - Yoonjay Han
- Department of Materials Science and Engineering , Seoul National University , Seoul 08826 , Republic of Korea
| | - Jonghee Lee
- Department of Creative Convergence Engineering , Hanbat National University , Daejeon 34158 , Republic of Korea
| | - Byounggon Yu
- Flexible Information Device Research Section , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
| | - Nam Sung Cho
- Flexible Information Device Research Section , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
| | - Jeong-Ik Lee
- Flexible Information Device Research Section , Electronics and Telecommunications Research Institute (ETRI) , Daejeon 34129 , Republic of Korea
| | - Jang-Joo Kim
- Department of Materials Science and Engineering , Seoul National University , Seoul 08826 , Republic of Korea
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9
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Jung HJ, Ahn JY, Lee JI, Bae JY, Kim HL, Suh HY, Youn JI, Park MY. Analysis of the number of enlarged pores according to site, age, and sex. Skin Res Technol 2018; 24:367-370. [PMID: 29393550 DOI: 10.1111/srt.12438] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/01/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND Increasing the number of enlarged pores causes cosmetic problems. The difference in the number of enlarged pores according to facial site, age, and sex is unclear. OBJECTIVE To analyze the distribution of the number of enlarged pores according to facial site, age, and sex. METHODS AND MATERIALS We analyzed the number of the enlarged pores and the percentage of wrinkles in the nose, forehead, and cheek from 434 polarized images. The measurement results were analyzed according to site, age, and sex. Relationship between enlarged pore counts and wrinkle severity was also analyzed. The study was conducted by using DermaVision,™ which can take cross-polarization, parallel polarization, and ultraviolet light images. RESULTS The enlarged pores of the nose and forehead were more prominent than in the cheeks. Pore counts were increased with age, and the increment was significant between the 30's and 40's. There was no significant difference by gender. Enlarged pore counts were related to wrinkle severity. CONCLUSIONS The number of enlarged pores differs depending on body site and increased with age. The enlarged pore counts correlate with wrinkle severity and the correlation varies depending on the body site.
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Affiliation(s)
- H J Jung
- Department of Dermatology, National Medical Center, Seoul, Korea
| | - J Y Ahn
- Department of Dermatology, National Medical Center, Seoul, Korea
| | - J I Lee
- Department of Dermatology, National Medical Center, Seoul, Korea
| | - J Y Bae
- Department of Dermatology, National Medical Center, Seoul, Korea
| | - H L Kim
- Department of Dermatology, National Medical Center, Seoul, Korea
| | - H Y Suh
- Department of Dermatology, National Medical Center, Seoul, Korea
| | - J I Youn
- Inshine Dermatology Clinic, Seoul, Korea
| | - M Y Park
- Department of Dermatology, National Medical Center, Seoul, Korea
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Shin JW, Cho H, Lee J, Moon J, Han JH, Kim K, Cho S, Lee JI, Kwon BH, Cho DH, Lee KM, Suemitsu M, Cho NS. Overcoming the efficiency limit of organic light-emitting diodes using ultra-thin and transparent graphene electrodes. Opt Express 2018; 26:617-626. [PMID: 29401944 DOI: 10.1364/oe.26.000617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 12/27/2017] [Indexed: 06/07/2023]
Abstract
We propose an effective way to enhance the out-coupling efficiencies of organic light-emitting diodes (OLEDs) using graphene as a transparent electrode. In this study, we investigated the detrimental adsorption and internal optics occurring in OLEDs with graphene anodes. The optical out-coupling efficiencies of previous OLEDs with transparent graphene electrodes barely exceeded those of OLEDs with conventional transparent electrodes because of the weak microcavity effect. To overcome this issue, we introduced an internal random scattering layer for light extraction and reduced the optical absorption of the graphene by reducing the number of layers in the multilayered graphene film. The efficiencies of the graphene-OLEDs increased significantly with decreasing the number of graphene layers, strongly indicating absorption reduction. The maximum light extraction efficiency was obtained by using a single-layer graphene electrode together with a scattering layer. As a result, a widened angular luminance distribution with a remarkable external quantum efficiency and a luminous efficacy enhancement of 52.8% and 48.5%, respectively, was achieved. Our approach provides a demonstration of graphene-OLED having a performance comparable to that of conventional OLEDs.
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11
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Lim JT, Kim J, Lee H, Moon J, Kwon BH, Ahn S, Cho NS, Ahn BW, Lee JI, Ihm K, Lim SC. Unraveled Face-Dependent Effects of Multilayered Graphene Embedded in Transparent Organic Light-Emitting Diodes. ACS Appl Mater Interfaces 2017; 9:43105-43112. [PMID: 29160058 DOI: 10.1021/acsami.7b13973] [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] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
With increasing demand for transparent conducting electrodes, graphene has attracted considerable attention, owing to its high electrical conductivity, high transmittance, low reflectance, flexibility, and tunable work function. Two faces of single-layer graphene are indistinguishable in its nature, and this idea has not been doubted even in multilayered graphene (MLG) because it is difficult to separately characterize the front (first-born) and the rear face (last-born) of MLG by using conventional analysis tools, such as Raman and ultraviolet spectroscopy, scanning probe microscopy, and sheet resistance. In this paper, we report the striking difference of the emission pattern and performance of transparent organic light-emitting diodes (OLEDs) depending on the adopted face of MLG and show the resolved chemical and physical states of both faces by using depth-selected absorption spectroscopy. Our results strongly support that the interface property between two different materials rules over the bulk property in the driving performance of OLEDs.
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Affiliation(s)
- Jong Tae Lim
- Flexible Device Research Group, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
| | - Jaesu Kim
- Department of Energy Science, Sungkyunkwan University , Suwon 16419, Korea
- IBS Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University , Suwon 16419, Republic of Korea
| | - Hyunkoo Lee
- Flexible Device Research Group, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
| | - Jaehyun Moon
- Flexible Device Research Group, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
| | - Byoung-Hwa Kwon
- Flexible Device Research Group, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
| | - Seongdeok Ahn
- Flexible Device Research Group, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
| | - Nam Sung Cho
- Flexible Device Research Group, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
| | - Byung-Wook Ahn
- Department of Energy Science, Sungkyunkwan University , Suwon 16419, Korea
- IBS Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University , Suwon 16419, Republic of Korea
| | - Jeong-Ik Lee
- Flexible Device Research Group, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
| | - Kyuwook Ihm
- Beamline Research Division, Pohang Accelerator Laboratory , Kyungbuk 37673, Republic of Korea
| | - Seong Chu Lim
- Department of Energy Science, Sungkyunkwan University , Suwon 16419, Korea
- IBS Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University , Suwon 16419, Republic of Korea
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12
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Lee JI, Bae JS, Min BS, Na MK. Antithrombotic and antiplatelet activities of indole alkaloids isolated from the edible insect Protaetia brevitarsis seulensis (Kolbe). Am J Transl Res 2017. [DOI: 10.1055/s-0037-1608127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- JI Lee
- College of Pharmacy, Chungnam National University, Daejeon, Korea, Republic of (South)
| | - JS Bae
- College of Pharmacy, CMRI, Research Institute of Pharmaceutical Sciences, BK21 Plus KNU Multi-Omics based Creative Drug Research Team Kyungpook National University, Daegu, Korea, Republic of (South)
| | - BS Min
- College of pharmacy, Catholic University of Daegu, Daegu, Korea, Republic of (South)
| | - MK Na
- College of Pharmacy, Chungnam National University, Daejeon, Korea, Republic of (South)
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Ahn SD, Kang SY, Cho SH, Yang JH, Lee H, Na BS, Koo JB, Park CW, Byun CW, Kwon BH, Cho NS, Hwang CS, Lee JI. 5-2: Invited Paper
: Ultrathin Stretchable Oxide Thin Film Transistor and Active Matrix Organic Light-Emitting Diode Displays. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/sdtp.11571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Seong-Deok Ahn
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
| | - Seung-Youl Kang
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
| | - Sung-Haeng Cho
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
| | - Jong-Heon Yang
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
| | - Hyunkoo Lee
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
| | - Bock-Soon Na
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
| | - Jae-Bon Koo
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
| | - Chan-Woo Park
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
| | - Chun-Won Byun
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
| | - Byoung-Hwa Kwon
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
| | - Nam-Sung Cho
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
| | - Chi-Sun Hwang
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
| | - Jeong-Ik Lee
- Reality Device Research Division; ICT Materials & Components & Research Laboratory, Electronics & Telecommunications Research Institute (ETRI); Daejeon Korea
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Cho H, Lee H, Lee J, Sung WJ, Kwon BH, Joo CW, Shin JW, Han JH, Moon J, Lee JI, Cho S, Cho NS. Stable angular emission spectra in white organic light-emitting diodes using graphene/PEDOT:PSS composite electrode. Opt Express 2017; 25:9734-9742. [PMID: 28468353 DOI: 10.1364/oe.25.009734] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this work, we suggest a graphene/ poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) composite as a transparent electrode for stabilizing white emission of organic light-emitting diodes (OLEDs). Graphene/PEDOT:PSS composite electrodes have increased reflectance when compared to graphene itself, but their reflectance is still lower than that of ITO itself. Changes in the reflectance of the composite electrode have the advantage of suppressing the angular spectral distortion of white emission OLEDs and achieving an efficiency of 16.6% for white OLEDs, comparable to that achieved by graphene-only electrodes. By controlling the OLED structure to compensate for the two-beam interference effect, the CIE color coordinate change (Δxy) of OLEDs based on graphene/PEDOT:PSS composite electrodes is 0.018, less than that based on graphene-only electrode, i.e.,0.027.
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Park YS, Han KH, Kim J, Cho DH, Lee J, Han Y, Lim JT, Cho NS, Yu B, Lee JI, Kim JJ. Crystallization-assisted nano-lens array fabrication for highly efficient and color stable organic light emitting diodes. Nanoscale 2017; 9:230-236. [PMID: 27906406 DOI: 10.1039/c6nr07798f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
To date, all deposition equipment has been developed to produce planar films. Thus lens arrays with a lens diameter of <1 mm have been manufactured by combining deposition with other technologies, such as masks, surface treatment, molding etc. Furthermore, a nano-lens array (NLA) with a sufficiently small lens diameter (<1 μm) is necessary to avoid image quality degradation in high resolution displays. In this study, an organic NLA made using a conventional deposition technique - without combining with other techniques - is reported. Very interestingly, grazing-incidence small-angle X-ray scattering (GI-SAXS) experiments indicate that the NLA is formed by the crystallization of organic molecules and the resulting increase in surface tension. The lens diameter can be tuned for use with any kind of light by controlling the process parameters. As an example of their potential applications, we use NLAs as a light extraction film for organic light emitting diodes (OLEDs). The NLA is integrated by directly depositing it on the top electrode of a collection of OLEDs. This is a dry process, meaning that it is fully compatible with the current OLED production process. Devices with NLAs exhibited a light extraction efficiency 1.5 times higher than devices without, which corresponds well with simulation results. The simulations show that this high efficiency is due to the reduction of the guided modes by scattering at the NLA. The NLAs also reduce image blurring, indicating that they increase color stability.
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Affiliation(s)
- Young-Sam Park
- Flexible Information Device Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon, 34129, Republic of Korea.
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Cho H, Joo CW, Lee J, Lee H, Moon J, Lee JI, Lee JY, Kang Y, Cho NS. Design and fabrication of two-stack tandem-type all-phosphorescent white organic light-emitting diode for achieving high color rendering index and luminous efficacy. Opt Express 2016; 24:24161-24168. [PMID: 27828247 DOI: 10.1364/oe.24.024161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
White organic light-emitting diodes (WOLEDs) are regarded as the general lighting source. Although color rendering index (CRI) and luminous efficacy are usually in trade-off relation, we will discuss about the optimization of both characteristics, particularly focusing on the spectrum of a blue emitter. The emission at a shorter wavelength is substantially important for achieving very high CRI (> 90). The luminous efficacy of a phosphorescent blue emitter is low as its color falls in the deeper blue range; however, that does not show any significant influence on the WOLEDs. WOLEDs with different blue dopants are compared to confirm the calculation of the CRI and luminous efficacy, and the optimized WOLEDs exhibit luminous efficacy of 38.3 lm/W and CRI of 90.9.
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Park SK, Kwark YJ, Nam S, Park S, Park B, Yun S, Moon J, Lee JI, Yu B, Kyung KU. Wrinkle structures formed by formulating UV-crosslinkable liquid prepolymers. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.07.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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18
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Lee JI, Yoon RG, Lee JH, Park JW, Yoo MH, Ahn JH, Chung JW, Park HJ. Prognostic Value of Labyrinthine 3D-FLAIR Abnormalities in Idiopathic Sudden Sensorineural Hearing Loss. AJNR Am J Neuroradiol 2016; 37:2317-2322. [PMID: 27516239 DOI: 10.3174/ajnr.a4901] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 06/16/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE According to recent research, modern MR imaging can detect the presense of abnormalities on labyrinthine. Our aim was to report the patterns and prognostic role of abnormal findings on labyrinthine imaging in patients with sudden sensorineural hearing loss. MATERIALS AND METHODS This study comprised 113 patients who were diagnosed with unilateral sudden sensorineural hearing loss and underwent 3T MR imaging, including pre-/postcontrast 3D fluid-attenuated inversion recovery and T1-weighted imaging. We analyzed abnormalities on MR imaging and correlated them with audiometric results. RESULTS Thirty-one (27%) patients showed abnormal findings on labyrinthine MR imaging in the affected ear. The initial/final hearing levels of the MRI+ group (91 ± 25/73 ± 27 dB hearing loss) were significantly worse than those of the MRI- group (69 ± 30/48 ± 24 dB hearing loss). The incidence of abnormalities on labyrinthine MR imaging was significantly lower (3 of 40, 8%) in 40 patients with initial mild-to-moderate hearing loss than in those with profound hearing loss (16 of 34, 47%). Considering hearing improvement by the Siegel criteria, the rate of complete or partial recovery was significantly higher in the MRI- group (34%) than in the MRI+ group (10%). In patients with initial severe or profound hearing loss, the MRI- group showed greater hearing improvement (38 ± 21 dB) than the MRI+ group (23 ± 22 dB). CONCLUSIONS Abnormalities on labyrinthine MR imaging were found in 27% of patients with sudden sensorineural hearing loss. The initial hearing loss was worse in the MRI+ group than in the MRI- group. In patients with initial severe and profound hearing loss, the presence of abnormalities on labyrinthine MR imaging indicated a poor prognosis.
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Affiliation(s)
- J I Lee
- From the Departments of Otolaryngology (J.I.L., J.W.P., J.H.A., J.W.C., H.J.P.)
| | - R G Yoon
- Department of Radiology (R.G.Y.), Catholic Kwandong University International St. Mary's Hospital, Catholic Kwandong University College of Medicine, Incheon, Korea
| | - J H Lee
- Radiology (J.H.L.), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - J W Park
- From the Departments of Otolaryngology (J.I.L., J.W.P., J.H.A., J.W.C., H.J.P.)
| | - M H Yoo
- Department of Otolaryngology (M.H.Y.), College of Medicine, Kyungpook National University, Daegu, Korea
| | - J H Ahn
- From the Departments of Otolaryngology (J.I.L., J.W.P., J.H.A., J.W.C., H.J.P.)
| | - J W Chung
- From the Departments of Otolaryngology (J.I.L., J.W.P., J.H.A., J.W.C., H.J.P.)
| | - H J Park
- From the Departments of Otolaryngology (J.I.L., J.W.P., J.H.A., J.W.C., H.J.P.)
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19
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Lee K, Shin JW, Park JH, Lee J, Joo CW, Lee JI, Cho DH, Lim JT, Oh MC, Ju BK, Moon J. A Light Scattering Layer for Internal Light Extraction of Organic Light-Emitting Diodes Based on Silver Nanowires. ACS Appl Mater Interfaces 2016; 8:17409-17415. [PMID: 27314500 DOI: 10.1021/acsami.6b02924] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We propose and fabricate a random light scattering layer for light extraction in organic light-emitting diodes (OLEDs) with silver nanodots, which were obtained by melting silver nanowires. The OLED with the light scattering layer as an internal light extraction structure was enhanced by 49.1% for the integrated external quantum efficiency (EQE). When a wrinkle structure is simultaneously used for an external light extraction structure, the total enhancement of the integrated EQE was 65.3%. The EQE is maximized to 65.3% at a current level of 2.0 mA/cm(2). By applying an internal light scattering layer and wrinkle structure to an OLED, the variance in the emission spectra was negligible over a broad viewing angle. Power mode analyses with finite difference time domain (FDTD) simulations revealed that the use of a scattering layer effectively reduced the waveguiding mode while introducing non-negligible absorption. Our method offers an effective yet simple approach to achieve both efficiency enhancement and spectral stability for a wide range of OLED applications.
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Affiliation(s)
- Keunsoo Lee
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
- Display and Nanosystem Laboratory, College of Engineering, Korea University , Seoul 136-713, Republic of Korea
| | - Jin-Wook Shin
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
- Research Institute of Electrical Communication, Tohoku University , Sendai, Miyagi 980-8577, Japan
| | - Jun-Hwan Park
- School of Electrical Engineering, Pusan National University , Pusan (Busan) 609-735, Republic of Korea
| | - Jonghee Lee
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
| | - Chul Woong Joo
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
| | - Jeong-Ik Lee
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
| | - Doo-Hee Cho
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
| | - Jong Tae Lim
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
| | - Min-Cheol Oh
- School of Electrical Engineering, Pusan National University , Pusan (Busan) 609-735, Republic of Korea
| | - Byeong-Kwon Ju
- Display and Nanosystem Laboratory, College of Engineering, Korea University , Seoul 136-713, Republic of Korea
| | - Jaehyun Moon
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute , Daejeon 34129, Republic of Korea
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20
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Kim JH, Joo CW, Lee J, Seo YK, Han JW, Oh JY, Kim JS, Yu S, Lee JH, Lee JI, Yun C, Choi BH, Kim YH. Highly Conductive PEDOT:PSS Films with 1,3-Dimethyl-2-Imidazolidinone as Transparent Electrodes for Organic Light-Emitting Diodes. Macromol Rapid Commun 2016; 37:1427-33. [PMID: 27377555 DOI: 10.1002/marc.201600144] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 04/14/2016] [Indexed: 11/08/2022]
Abstract
UNLABELLED Highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) ( PEDOT PSS) films as transparent electrodes for organic light-emitting diodes (OLEDs) are doped with a new solvent 1,3-dimethyl-2-imidazolidinone (DMI) and are optimized using solvent post-treatment. The DMI doped PEDOT PSS films show significantly enhanced conductivities up to 812.1 S cm(-1) . The sheet resistance of the PEDOT PSS films doped with DMI is further reduced by various solvent post-treatment. The effect of solvent post-treatment on DMI doped PEDOT PSS films is investigated and is shown to reduce insulating PSS in the conductive films. The solvent posttreated PEDOT PSS films are successfully employed as transparent electrodes in white OLEDs. It is shown that the efficiency of OLEDs with the optimized DMI doped PEDOT PSS films is higher than that of reference OLEDs doped with a conventional solvent (ethylene glycol). The results present that the optimized PEDOT PSS films with the new solvent of DMI can be a promising transparent electrode for low-cost, efficient ITO-free white OLEDs.
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Affiliation(s)
- Jin Hee Kim
- Department of Display Engineering, Pukyong National University, Busan, 608-737, Republic of Korea
| | - Chul Woong Joo
- OLED Research Center, Electronics and Telecommunications Research Institute (ETRI), Daejeon, 305-700, Republic of Korea
| | - Jonghee Lee
- OLED Research Center, Electronics and Telecommunications Research Institute (ETRI), Daejeon, 305-700, Republic of Korea
| | - Yoon Kyung Seo
- Department of Display Engineering, Pukyong National University, Busan, 608-737, Republic of Korea
| | - Joo Won Han
- Department of Display Engineering, Pukyong National University, Busan, 608-737, Republic of Korea
| | - Ji Yoon Oh
- Department of Display Engineering, Pukyong National University, Busan, 608-737, Republic of Korea
| | - Jong Su Kim
- Department of Display Engineering, Pukyong National University, Busan, 608-737, Republic of Korea
| | - Seunggun Yu
- Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749, Republic of Korea
| | - Jae Hyun Lee
- Department of Creative Convergence Engineering, Hanbat National University, Daejeon, 305-719, Republic of Korea
| | - Jeong-Ik Lee
- OLED Research Center, Electronics and Telecommunications Research Institute (ETRI), Daejeon, 305-700, Republic of Korea
| | - Changhun Yun
- Center for Nano-Photonics Convergence Technology, Korea Institute of Industrial Technology, Gwangju, 500-480, Republic of Korea
| | - Bum Ho Choi
- Center for Nano-Photonics Convergence Technology, Korea Institute of Industrial Technology, Gwangju, 500-480, Republic of Korea
| | - Yong Hyun Kim
- Department of Display Engineering, Pukyong National University, Busan, 608-737, Republic of Korea.
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Lee JI, Balolong E, Han Y, Lee S. Stem cells for cartilage repair: what exactly were used for treatment, cultured adipose-derived stem cells or the unexpanded stromal vascular fraction? Osteoarthritis Cartilage 2016; 24:1302-3. [PMID: 26946247 DOI: 10.1016/j.joca.2016.01.990] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 01/10/2016] [Indexed: 02/02/2023]
Affiliation(s)
- J I Lee
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science and Technology, Konkuk University, Seoul, Republic of Korea; Department of Veterinary Medicine, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea.
| | - E Balolong
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science and Technology, Konkuk University, Seoul, Republic of Korea
| | - Y Han
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science and Technology, Konkuk University, Seoul, Republic of Korea
| | - S Lee
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science and Technology, Konkuk University, Seoul, Republic of Korea.
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Affiliation(s)
- J W Park
- Department of Orthopaedic Surgery, Korea University Ansan Hospital, Ansan, Korea
| | - K H Lee
- Department of Orthopaedic Surgery, Hanyang University Seoul Hospital, Seoul, Korea
| | - J I Lee
- Department of Orthopaedic Surgery, Hanyang University Guri Hospital, Guri, Korea
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Pradhan AS, Lee JI, Kim JL. On the scenario of passive dosimeters in personnel monitoring: Relevance to diagnostic radiology and fluoroscopy-based interventional cardiology. J Med Phys 2016; 41:81-4. [PMID: 27217618 PMCID: PMC4871007 DOI: 10.4103/0971-6203.181634] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- A S Pradhan
- Radiation Dosimetry Team, Korea Atomic Energy Research Institute, Yuseong, Daejeon, Republic of Korea
| | - J I Lee
- Radiation Dosimetry Team, Korea Atomic Energy Research Institute, Yuseong, Daejeon, Republic of Korea
| | - J L Kim
- Radiation Dosimetry Team, Korea Atomic Energy Research Institute, Yuseong, Daejeon, Republic of Korea
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Pyo B, Joo CW, Kim HS, Kwon BH, Lee JI, Lee J, Suh MC. A nanoporous polymer film as a diffuser as well as a light extraction component for top emitting organic light emitting diodes with a strong microcavity structure. Nanoscale 2016; 8:8575-8582. [PMID: 27048737 DOI: 10.1039/c6nr00868b] [Citation(s) in RCA: 6] [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] [Indexed: 06/05/2023]
Abstract
To improve the viewing angle characteristic as well as the light extraction effect of strong microcavity devices, we fabricated a nanoporous polymer film (NPF) as a scattering medium as well as a light extraction component. We designed two types of organic light emitting diodes (OLEDs) with a strong microcavity effect by changing the thickness of the hole transport layer (HTL; e.g., 30 nm and 60 nm) to investigate two different scattering effects of the NPF. Very interestingly, we could observe a significant enhancement of the external quantum efficiency (EQE) for each device (30 nm thick HTL: 18.0%, 60 nm thick HTL: 31.6%) when we attached a NPF formed on a 125 μm thick PET film coated with the NPF. Furthermore, the NPF successfully suppressed the viewing angle dependence to realize ideal angular emission even in the two extreme microcavity conditions although they are still different from that of a Lambertian distribution.
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Affiliation(s)
- Beom Pyo
- Dept. of Information Display, Kyung Hee University, Seoul 02447, Republic of Korea.
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25
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Kang BK, Cho H, Han JH, Shin JW, Song J, Park SK, Lee J, Joo CW, Kim E, Yoo S, Lee JI, Ju BK, Moon J. Area-selective external light extraction for metal bus equipped large area transparent organic light-emitting diodes. Opt Express 2016; 24:5356-5365. [PMID: 29092359 DOI: 10.1364/oe.24.005356] [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: 06/07/2023]
Abstract
Area-selective external light extraction films based on wrinkle structured films were applied to large transparent organic light-emitting diodes (TOLEDs) with auxiliary metal buses. To be specific, on the external surface of the glass, we selectively formed a wrinkle structured film, which was aligned to the auxiliary metal electrodes. The wrinkle-structured film was patterned using a photo-mask and UV curing, which has the same shape of the auxiliary metal electrodes. With this area-selective film, it was possible to enhance the external quantum efficiencies of the bottom and top emissions TOLEDs by 15.7% and 15.1%, respectively, without significant loss in transmittance. Widened angular luminance distributions were also achieved in both emissions directions.
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26
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Lee K, Lee J, Kim E, Lee JI, Cho DH, Lim JT, Joo CW, Kim JY, Yoo S, Ju BK, Moon J. Simultaneously enhanced device efficiency, stabilized chromaticity of organic light emitting diodes with lambertian emission characteristic by random convex lenses. Nanotechnology 2016; 27:075202. [PMID: 26778539 DOI: 10.1088/0957-4484/27/7/075202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An optical functional film applicable to various lighting devices is demonstrated in this study. The phase separation of two immiscible polymers in a common solvent was used to fabricate the film. In this paper, a self-organized lens-like structure is realized in this manner with optical OLED functional film. For an OLED, there are a few optical drawbacks, including light confinement or viewing angle distortion. By applying the optical film to an OLED, the angular spectra distortion resulting from the designed organic stack which produced the highest efficiency was successfully stabilized, simultaneously enhancing the efficiency of the OLED. We prove the effect of the film on the efficiency of OLEDs through an optical simulation. With the capability to overcome the main drawbacks of OLEDs, we contend that the proposed film can be applied to various lighting devices.
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Affiliation(s)
- Keunsoo Lee
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Korea
- Display and Nanosystem Laboratory, College of Engineering, Korea University, Seoul 02842, Korea
| | - Jonghee Lee
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Korea
| | - Eunhye Kim
- Department of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141, Korea
| | - Jeong-Ik Lee
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Korea
| | - Doo-Hee Cho
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Korea
| | - Jong Tae Lim
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Korea
| | - Chul Woong Joo
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Korea
| | - Joo Yeon Kim
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Korea
| | - Seunghyup Yoo
- Department of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141, Korea
| | - Byeong-Kwon Ju
- Display and Nanosystem Laboratory, College of Engineering, Korea University, Seoul 02842, Korea
| | - Jaehyun Moon
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Korea
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27
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Yoon T, Kim JH, Choi JH, Jung DY, Park IJ, Choi SY, Cho NS, Lee JI, Kwon YD, Cho S, Kim TS. Healing Graphene Defects Using Selective Electrochemical Deposition: Toward Flexible and Stretchable Devices. ACS Nano 2016; 10:1539-45. [PMID: 26715053 DOI: 10.1021/acsnano.5b07098] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Graphene produced by chemical-vapor-deposition inevitably has defects such as grain boundaries, pinholes, wrinkles, and cracks, which are the most significant obstacles for the realization of superior properties of pristine graphene. Despite efforts to reduce these defects during synthesis, significant damages are further induced during integration and operation of flexible and stretchable applications. Therefore, defect healing is required in order to recover the ideal properties of graphene. Here, the electrical and mechanical properties of graphene are healed on the basis of selective electrochemical deposition on graphene defects. By exploiting the high current density on the defects during the electrodeposition, metal ions such as silver and gold can be selectively reduced. The process is universally applicable to conductive and insulating substrates because graphene can serve as a conducting channel of electrons. The physically filled metal on the defects improves the electrical conductivity and mechanical stretchability by means of reducing contact resistance and crack density. The healing of graphene defects is enabled by the solution-based room temperature electrodeposition process, which broadens the use of graphene as an engineering material.
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Affiliation(s)
| | | | | | | | | | | | - Nam Sung Cho
- Electronics and Telecommunications Research Institute , Daejeon 34129, Korea
| | - Jeong-Ik Lee
- Electronics and Telecommunications Research Institute , Daejeon 34129, Korea
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28
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Tae Lim J, Lee H, Cho H, Kwon BH, Sung Cho N, Kuk Lee B, Park J, Kim J, Han JH, Yang JH, Yu BG, Hwang CS, Chu Lim S, Lee JI. Flexion bonding transfer of multilayered graphene as a top electrode in transparent organic light-emitting diodes. Sci Rep 2015; 5:17748. [PMID: 26626439 PMCID: PMC4667220 DOI: 10.1038/srep17748] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [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: 05/27/2015] [Accepted: 11/05/2015] [Indexed: 11/09/2022] Open
Abstract
Graphene has attracted considerable attention as a next-generation transparent conducting electrode, because of its high electrical conductivity and optical transparency. Various optoelectronic devices comprising graphene as a bottom electrode, such as organic light-emitting diodes (OLEDs), organic photovoltaics, quantum-dot LEDs, and light-emitting electrochemical cells, have recently been reported. However, performance of optoelectronic devices using graphene as top electrodes is limited, because the lamination process through which graphene is positioned as the top layer of these conventional OLEDs is a lack of control in the surface roughness, the gapless contact, and the flexion bonding between graphene and organic layer of the device. Here, a multilayered graphene (MLG) as a top electrode is successfully implanted, via dry bonding, onto the top organic layer of transparent OLED (TOLED) with flexion patterns. The performance of the TOLED with MLG electrode is comparable to that of a conventional TOLED with a semi-transparent thin-Ag top electrode, because the MLG electrode makes a contact with the TOLED with no residue. In addition, we successfully fabricate a large-size transparent segment panel using the developed MLG electrode. Therefore, we believe that the flexion bonding technology presented in this work is applicable to various optoelectronic devices.
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Affiliation(s)
- Jong Tae Lim
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea
| | - Hyunkoo Lee
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea
| | - Hyunsu Cho
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea
| | - Byoung-Hwa Kwon
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea
| | - Nam Sung Cho
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea
| | - Bong Kuk Lee
- IT Convergence Technology Research Laboratory, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea
| | - Jonghyurk Park
- Smart I/O Control Research Section, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea
| | - Jaesu Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Korea
| | - Jun-Han Han
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea
| | - Jong-Heon Yang
- Smart I/O Control Research Section, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea
| | - Byoung-Gon Yu
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea
| | - Chi-Sun Hwang
- Smart I/O Control Research Section, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea
| | - Seong Chu Lim
- Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Korea.,IBS Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 440-746, Korea
| | - Jeong-Ik Lee
- Soft I/O Interface Research Section, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea
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29
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Lee KM, Kim H, Nemeno JG, Yang W, Yoon J, Lee S, Lee JI. Natural cardiac extracellular matrix sheet as a biomaterial for cardiomyocyte transplantation. Transplant Proc 2015; 47:751-6. [PMID: 25891725 DOI: 10.1016/j.transproceed.2014.12.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 12/31/2014] [Indexed: 11/26/2022]
Abstract
Cardiovascular diseases associated with myocardial infarction are among the major causes of death worldwide due to the limited regenerative capacity of cardiac tissues. Although various approaches, such as biosynthetic biomaterials, have been developed to promote postinfarction cardiac regeneration, a number of limitations, including the immune complications caused by biodegradation of these scaffolds and insufficient cell migration, need to be overcome prior to their clinical application. Hence, the development of natural biomaterials to support myocardial regeneration is crucial. Here, we investigated the effects of a natural biomaterial, cardiac extracellular matrix (ECM) on the proliferation and maintenance of cardiomyocytes in order to assess its suitability for cardiomyocyte expansion. The ECM components not only provide mechanical support, but also induce and preserve the required phenotypic and functional characteristics of the cells. We prepared ECM sheets from decellularized cardiac sections. Cardiomyocytes were then cultured with and without these cardiac ECM sheets. We compared the proliferation rates and phenotypes, and cardiac gene and protein expression, of the cultured cardiomyocytes by automatic cell counting and the MTT assay, microscopy, and RT-PCR and western blotting, respectively. The cardiomyocytes cultured with the natural cardiac ECM sheets exhibited higher proliferation rates and cardiac gene and protein expression than those cultured without the ECM sheets. Our results demonstrate that the ECM sheets are suitable for use in cardiomyocyte transplantation and can provide a novel in vitro model for investigating cell and ECM interactions. We hypothesize that these ECM sheets can be used in the future to improve cardiac transplantation strategies.
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Affiliation(s)
- K M Lee
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science & Technology (IBST), Konkuk University, Seoul, Republic of Korea
| | - H Kim
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science & Technology (IBST), Konkuk University, Seoul, Republic of Korea
| | - J G Nemeno
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science & Technology (IBST), Konkuk University, Seoul, Republic of Korea
| | - W Yang
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science & Technology (IBST), Konkuk University, Seoul, Republic of Korea
| | - J Yoon
- IT Design Fusion Program, Graduate School Of NID Fusion Technology, Seoul National University of Science and Technology, Seoul, Republic of Korea
| | - S Lee
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science & Technology (IBST), Konkuk University, Seoul, Republic of Korea
| | - J I Lee
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science & Technology (IBST), Konkuk University, Seoul, Republic of Korea; Department of Veterinary Medicine, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea.
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30
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Chung J, Cho H, Koh TW, Lee J, Kim E, Lee J, Lee JI, Yoo S. Towards highly efficient and highly transparent OLEDs: advanced considerations for emission zone coupled with capping layer design. Opt Express 2015; 23:27306-27314. [PMID: 26480391 DOI: 10.1364/oe.23.027306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Strategies to achieve efficient transparent organic light-emitting diodes (TrOLEDs) are presented. The emission zone position is carefully adjusted by monitoring the optical phase change upon reflection from the top electrode, which is significant when the thickness of the capping layer changes. With the proposed design strategy, external quantum efficiency and transmittance values as high as 15% and 80% are demonstrated simultaneously. The effect of surface plasmon polariton (SPP) loss from thin metal electrodes is also taken into account to correctly describe the full scaling behavior of the efficiency of TrOLEDs over key optical design parameters.
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31
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Park SK, Kwark YJ, Moon J, Joo CW, Yu B, Lee JI. Finely Formed, Kinetically Modulated Wrinkle Structures in UV-Crosslinkable Liquid Prepolymers. Macromol Rapid Commun 2015; 36:2006-11. [DOI: 10.1002/marc.201500370] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/12/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Seung Koo Park
- Soft I/O Interface Research Section; Smart I/O Platform Research Department; Information & Communications Core Technology Research Laboratory; Electronics and Telecommunications Research Institute; 218 Gajeongno Yuseong-gu Daejeon 34129 South Korea
| | - Young-Je Kwark
- Department of Organic Materials and Fiber Engineering; Soongsil University; 369 Sangdoro Dongjak-gu Seoul 06978 South Korea
| | - Jaehyun Moon
- Soft I/O Interface Research Section; Smart I/O Platform Research Department; Information & Communications Core Technology Research Laboratory; Electronics and Telecommunications Research Institute; 218 Gajeongno Yuseong-gu Daejeon 34129 South Korea
| | - Chul Woong Joo
- Soft I/O Interface Research Section; Smart I/O Platform Research Department; Information & Communications Core Technology Research Laboratory; Electronics and Telecommunications Research Institute; 218 Gajeongno Yuseong-gu Daejeon 34129 South Korea
| | - Byounggon Yu
- Soft I/O Interface Research Section; Smart I/O Platform Research Department; Information & Communications Core Technology Research Laboratory; Electronics and Telecommunications Research Institute; 218 Gajeongno Yuseong-gu Daejeon 34129 South Korea
| | - Jeong-Ik Lee
- Soft I/O Interface Research Section; Smart I/O Platform Research Department; Information & Communications Core Technology Research Laboratory; Electronics and Telecommunications Research Institute; 218 Gajeongno Yuseong-gu Daejeon 34129 South Korea
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32
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Mizuno M, Takebe T, Kobayashi S, Kimura S, Masutani M, Lee S, Jo YH, Lee JI, Taniguchi H. Elastic cartilage reconstruction by transplantation of cultured hyaline cartilage-derived chondrocytes. Transplant Proc 2015; 46:1217-21. [PMID: 24815164 DOI: 10.1016/j.transproceed.2013.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 11/23/2013] [Accepted: 12/10/2013] [Indexed: 11/18/2022]
Abstract
Current surgical intervention of craniofacial defects caused by injuries or abnormalities uses reconstructive materials, such as autologous cartilage grafts. Transplantation of autologous tissues, however, places a significant invasiveness on patients, and many efforts have been made for establishing an alternative graft. Recently, we and others have shown the potential use of reconstructed elastic cartilage from ear-derived chondrocytes or progenitors with the unique elastic properties. Here, we examined the differentiation potential of canine joint cartilage-derived chondrocytes into elastic cartilage for expanding the cell sources, such as hyaline cartilage. Articular chondrocytes are isolated from canine joint, cultivated, and compared regarding characteristic differences with auricular chondrocytes, including proliferation rates, gene expression, extracellular matrix production, and cartilage reconstruction capability after transplantation. Canine articular chondrocytes proliferated less robustly than auricular chondrocytes, but there was no significant difference in the amount of sulfated glycosaminoglycan produced from redifferentiated chondrocytes. Furthermore, in vitro expanded and redifferentiated articular chondrocytes have been shown to reconstruct elastic cartilage on transplantation that has histologic characteristics distinct from hyaline cartilage. Taken together, cultured hyaline cartilage-derived chondrocytes are a possible cell source for elastic cartilage reconstruction.
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Affiliation(s)
- M Mizuno
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - T Takebe
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan; Project Leader of Advanced Medical Research Center, Yokohama City University, Yokohama, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Japan
| | - S Kobayashi
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan; Department of Plastic and Reconstructive Surgery, Kanagawa Children's Medical Center, Yokohama, Japan
| | - S Kimura
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - M Masutani
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - S Lee
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science and Technology (IBST), Konkuk University, Seoul, Republic of Korea
| | - Y H Jo
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science and Technology (IBST), Konkuk University, Seoul, Republic of Korea
| | - J I Lee
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science and Technology (IBST), Konkuk University, Seoul, Republic of Korea
| | - H Taniguchi
- Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan; Project Leader of Advanced Medical Research Center, Yokohama City University, Yokohama, Japan.
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33
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Hahn SH, Lee J, Chu HY, Lee JI, Lee YJ, Hwang J, Shin SC, Kim YH. New Blue Emitting Material with Asymmetric Limb Structure. J Nanosci Nanotechnol 2015; 15:355-359. [PMID: 26328360 DOI: 10.1166/jnn.2015.8820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The new assymmetric limb-structured blue light emitting material, composed of anthracene main core, naphthalene units at 9, 10-position of anthracene and xylene units at 2,3-positon of anthracene, was designed and synthesized. The three-dimensional structure from theoretical calculation was characterized to elucidate non-copolar structure with inhibited intermolecular interaction. The limb-structured blue material was thermally stable up to 373 degrees C with T(g) of 143 degrees C. ITO/TAPC/CBP (3% BMPNA)/Bphen/LiF/Al device exhibits the maximum quantum efficiency of 3.42% and maximum current efficiency of 3.07 cd/A with deep blue emission of (0.141, 0.115) CIE coordinates.
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Abstract
In order to reduce power consumption in OLED lighting, polymeric lighting extraction films were integrated directly on the backside of green emissive bottom-emitting OLED glass substrates. The luminous efficacy and external quantum efficiency were improved by up to 50%.
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Affiliation(s)
- Joo Yeon Kim
- Soft I/O Interface Research Section
- Components & Materials Research Laboratory
- Electronics and Telecommunications Research Institute (ETRI)
- Daejeon
- Korea
| | - Chul Woong Joo
- Soft I/O Interface Research Section
- Components & Materials Research Laboratory
- Electronics and Telecommunications Research Institute (ETRI)
- Daejeon
- Korea
| | - Jonghee Lee
- Soft I/O Interface Research Section
- Components & Materials Research Laboratory
- Electronics and Telecommunications Research Institute (ETRI)
- Daejeon
- Korea
| | - Jong-Chang Woo
- Nano Convergence Sensor Research Section
- Components & Materials Research Laboratory
- Electronics and Telecommunications Research Institute (ETRI)
- Daejeon
- Korea
| | - Ji-Young Oh
- Soft I/O Interface Research Section
- Components & Materials Research Laboratory
- Electronics and Telecommunications Research Institute (ETRI)
- Daejeon
- Korea
| | - Nam Seob Baek
- Synapse Devices Creative Research Center
- Electronics and Telecommunications Research Institute (ETRI)
- Daejeon
- Korea
| | - Hye Yong Chu
- Smart I/O Platform Research Department
- Electronics and Telecommunications Research Institute (ETRI)
- Daejeon
- Korea
| | - Jeong-Ik Lee
- Soft I/O Interface Research Section
- Components & Materials Research Laboratory
- Electronics and Telecommunications Research Institute (ETRI)
- Daejeon
- Korea
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Cho DH, Shin JW, Joo CW, Lee J, Park SK, Moon J, Cho NS, Chu HY, Lee JI. Light diffusing effects of nano and micro-structures on OLED with microcavity. Opt Express 2014; 22 Suppl 6:A1507-A1518. [PMID: 25607307 DOI: 10.1364/oe.22.0a1507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We examined the light diffusing effects of nano and micro-structures on microcavity designed OLEDs. The results of FDTD simulations and experiments showed that the pillar shaped nano-structure was more effective than the concave micro-structure for light diffusing of microcavity OLEDs. The sharp luminance distribution of the microcavity OLED was changed to near Lambertian luminance distribution by the nano-structure, and light diffusing effects increased with the height of the nano-structure. Furthermore, the nano-structure has advantages including light extraction of the substrate mode, reproducibility of manufacturing process, and minimizing pixel blur problems in an OLED display panel. The nano-structure is a promising candidate for a light diffuser, resolving the viewing angle problems in microcavity OLEDs.
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Choi H, Choi JS, Kim JS, Choe JH, Chung KH, Shin JW, Kim JT, Youn DH, Kim KC, Lee JI, Choi SY, Kim P, Choi CG, Yu YJ. Flexible and transparent gas molecule sensor integrated with sensing and heating graphene layers. Small 2014; 10:3685-91. [PMID: 24832822 DOI: 10.1002/smll.201400434] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 04/01/2014] [Indexed: 05/13/2023]
Abstract
Graphene leading to high surface-to-volume ratio and outstanding conductivity is applied for gas molecule sensing with fully utilizing its unique transparent and flexible functionalities which cannot be expected from solid-state gas sensors. In order to attain a fast response and rapid recovering time, the flexible sensors also require integrated flexible and transparent heaters. Here, large-scale flexible and transparent gas molecule sensor devices, integrated with a graphene sensing channel and a graphene transparent heater for fast recovering operation, are demonstrated. This combined all-graphene device structure enables an overall device optical transmittance that exceeds 90% and reliable sensing performance with a bending strain of less than 1.4%. In particular, it is possible to classify the fast (≈14 s) and slow (≈95 s) response due to sp(2) -carbon bonding and disorders on graphene and the self-integrated graphene heater leads to the rapid recovery (≈11 s) of a 2 cm × 2 cm sized sensor with reproducible sensing cycles, including full recovery steps without significant signal degradation under exposure to NO2 gas.
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Affiliation(s)
- Hongkyw Choi
- Creative Research Center for Graphene Electronics, Electronics and Telecommunications Research Institute (ETRI), 218 Gajeong-ro, Yuseong-gu, Daejeon, 305-700, Korea; Department of Advanced Device Technology, University of Science and Technology (UST), Daejeon, 305-333, Korea
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Huh JW, Shin JW, Cho DH, Moon J, Joo CW, Park SK, Hwang J, Cho NS, Lee J, Han JH, Chu HY, Lee JI. A randomly nano-structured scattering layer for transparent organic light emitting diodes. Nanoscale 2014; 6:10727-10733. [PMID: 25099663 DOI: 10.1039/c4nr01520g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A random scattering layer (RSL) consisting of a random nano-structure (RNS) and a high refractive index planarization layer (HRI PL) is suggested and demonstrated as an efficient internal light-extracting layer for transparent organic light emitting diodes (TOLEDs). By introducing the RSL, a remarkable enhancement of 40% and 46% in external quantum efficiency (EQE) and luminous efficacy (LE) was achieved without causing deterioration in the transmittance. Additionally, with the use of the RSL, the viewing angle dependency of EL spectra was reduced to a marginal degree. The results were interpreted as the stronger influence of the scattering effect over the microcavity. The RSL can be applied widely in TOLEDs as an effective light-extracting layer for extracting the waveguide mode of confined light at the indium tin oxide (ITO)/OLED stack without introducing spectral changes in TOLEDs.
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Affiliation(s)
- Jin Woo Huh
- OLED Research Center, Electronics and Telecommunications Research Institute, Daejeon 305-700, Korea.
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Mizukami K, Yabuki A, Endoh D, Chang HS, Lee KW, Nakayama M, Kushida K, Kohyama M, Lee JI, Yamato O. Investigation of parallel and simultaneous selection for collie eye anomaly and ivermectin toxicosis. Vet Rec 2014; 175:174. [PMID: 24939474 DOI: 10.1136/vr.102015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- K Mizukami
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima 890-0065, Japan
| | - A Yabuki
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima 890-0065, Japan
| | - D Endoh
- Department of Veterinary Radiology, School of Veterinary Medicine, Rakuno Gakuen University, 582 Midorimachi, Bunkyodai, Ebetsu, Hokkaido 069-8501, Japan
| | - H S Chang
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima 890-0065, Japan
| | - K W Lee
- Laboratory of Veterinary Internal Medicine, College of Veterinary Medicine, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 702-701, Korea
| | - M Nakayama
- Nakayama Veterinary Hospital, 6-1 Minamifukuro, Nara, Nara 630-8342, Japan
| | - K Kushida
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima 890-0065, Japan
| | - M Kohyama
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima 890-0065, Japan
| | - J I Lee
- Laboratory of Veterinary Public Health I, College of Veterinary Medicine, Chonnam National University, 300 Yonbongdong, Bukgu, Gwangju 500-757, Korea
| | - O Yamato
- Laboratory of Clinical Pathology, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima 890-0065, Japan
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Schreiner A, Hargarter L, Hitschfield K, Lee JI, Lenskaya I, Sulaiman AH, Diels J. Clinical effectiveness and resource utilization of paliperidone ER for schizophrenia: Pharmacoepidemiologic International Longitudinal Antipsychotic Registry (PILAR). Curr Med Res Opin 2014; 30:1279-89. [PMID: 24597755 DOI: 10.1185/03007995.2014.898630] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [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] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To document prescribing patterns in clinical practice and assess long-term outcomes related to initiation of paliperidone ER and other oral antipsychotics among patients with schizophrenia in a naturalistic setting. RESEARCH DESIGN AND METHODS An international, non-interventional, naturalistic study of adult patients (≥18 years) with schizophrenia. Patients were assigned to the relevant treatment group (paliperidone ER or 'all other oral antipsychotics') after switching to, or initiating, oral antipsychotic treatment. Retrospective 12 month data collection was followed by 12 month prospective data collection, with 3-monthly assessments. The primary endpoint was time to all-cause discontinuation of new medication. Secondary endpoints included Clinical Global Impression-Severity (CGI-S) score, Clinical Global Impression-Schizophrenia (CGI-SCH) score, Personal and Social Performance (PSP) score, health-related quality of life (HR-QoL) and quality of sleep, evaluation of healthcare resource utilization and patient's treatment satisfaction. RESULTS A total of 4051 patients were included in the intent-to-treat (ITT) analysis set. All-cause study discontinuation rates were comparable between the paliperidone ER group (16.8%) and the 'all other oral antipsychotics' group (15.5%). There was no difference in the time to discontinuation of newly initiated antipsychotic treatments between paliperidone ER and 'all other oral antipsychotics' groups. Paliperidone ER was associated with greater improvements from baseline to endpoint in both the PSP scale score (+14.2 vs +13.1, p = 0.041) and the physical component of quality of life (SF-12 Physical scores; +3.9 vs +2.9, p = 0.003) compared to 'all other oral antipsychotics'. Improvements in mean CGI-S score, CGI-SCH score, HR-QoL, quality of sleep and daytime drowsiness, as well as patients' treatment satisfaction were comparable between treatment groups. The incidence of adverse events was comparable between groups. CONCLUSIONS This study provides valuable data on the prescribing habits and treatment outcomes associated with use of paliperidone ER in everyday clinical practice, and supports previous findings of the favorable functional improvement and treatment satisfaction associated with paliperidone ER. CLINICAL TRIAL REGISTRATION NCT00696813; R076477SCH4015 (Register of German Association of Research-based Pharmaceutical Companies [VFA] http://www.vfa.de/de/arzneimittel-forschung/datenbanken-zu-arzneimitteln/nisdb).
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Shin JW, Cho DH, Moon J, Joo CW, Lee J, Huh JW, Park SK, Han JH, Cho NS, Hwang J, Chu HY, Lee JI. Random nanostructure scattering layer for suppression of microcavity effect and light extraction in OLEDs. Opt Lett 2014; 39:3527-3530. [PMID: 24978528 DOI: 10.1364/ol.39.003527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this study, we investigated the effect of a random nanostructure scattering layer (RSL) on the microcavity and light extraction in organic light emitting diodes (OLEDs). In the case of the conventional OLED, the optical properties change with the thickness of the hole transporting layer (HTL) because of the presence of a microcavity. However, OLEDs equipped with the an RSL showed similar values of external quantum efficiency and luminous efficacy regardless of the HTL thickness. These phenomena can be understood by the scattering effect because of the RSL, which suppresses the microcavity effect and extracts the light confined in the device. Moreover, OLEDs with the RSL led to reduced spectrum and color changes with the viewing angle.
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Abstract
WHAT IS KNOWN AND OBJECTIVE Mucopolysaccharidoses (MPSs) are a group of rare inherited metabolic diseases caused by genetic defects in the production of lysosomal enzymes. MPSs are clinically heterogeneous and are characterized by progressive deterioration in visceral, skeletal and neurological functions. This article aims to review the classification and pathophysiology of MPSs and discuss current therapies and new targeted agents under development. METHODS A Medline search through PubMed was performed for relevant articles and treatment guidelines on MPSs published in English for years 1970 to September of 2013 inclusive. The references listed in the identified articles, prescribing information of the drugs approved for the treatment of MPSs, as well as recent clinical trial information posted on Clinicaltrials.gov website, were reviewed. RESULTS AND DISCUSSION Until recently, supportive care was the only option available for the management of MPSs. In the early 2000s, enzyme replacement therapy (ERT) was approved by the United States Food and Drug Administration (FDA) for the treatment of MPS I, II and VI. Clinical trials of ERT showed substantial improvements in patients' somatic symptoms; however, no benefit was found in the neurological symptoms because the enzymes do not readily cross the blood-brain barrier (BBB). Haematopoietic stem cell transplantation (HSCT), another potentially curative treatment, is not routinely advocated in clinical practice due to its high risk profile and lack of evidence for efficacy, except in preserving cognition and prolonging survival in young patients with severe MPS I. In recent years, substrate reduction therapy (SRT) and gene therapy have been rapidly gaining greater recognition as potential therapeutic avenues. WHAT IS NEW AND CONCLUSION Enzyme replacement therapy (ERT) is effective for the treatment of many somatic symptoms, particularly walking ability and respiratory function, and remains the mainstay of MPS treatment. The usefulness of HSCT has not been established adequately for most MPSs. Although still under investigation, SRT and gene therapy are promising MPS treatments that may prevent the neurodegeneration not affected by ERT.
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Affiliation(s)
- H Noh
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon, Korea; Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, Incheon, Korea
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Ju MK, Jeong JH, Lee JI, Kim YS, Kim MS. Proliferation and functional assessment of pseudo-islets with the use of pancreatic endocrine cells. Transplant Proc 2014; 45:1885-8. [PMID: 23769063 DOI: 10.1016/j.transproceed.2012.12.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 12/31/2012] [Indexed: 11/26/2022]
Abstract
Many obstacles beset islet transplantation, particularly insufficient tissue mass. Previously, we reported production of pseudo-islets. In addition, there have been reports in which coculture with pancreatic islet and bone marrow mesenchymal stem cells (BMSCs) demonstrated positive effects on pancreatic islet function. The purpose of this study was to perform morphologic and functional evaluations of pancreatic pseudo-islets cocultured with BMSCs. Pancreatic endocrine cells (PECs) were collected with a previously reported method; bone marrow was aspirated from the rat femur. Subsequently, PECs and BMSCs cocultured at high density on low-cell-binding culture dishes kept suspended by shaking. The functionality and characteristics of the mixed cell complexes were evaluated by glucose challenge, insulin enzyme-linked immunosorbent assay, reverse-transcription polymerase chain reaction, and immunohistochemistry. Through expansion for 2 weeks in continuous culture passages, ∼1 million PECs were recovered after aggregation. They presented spherical shapes and sizes similar to naïve islets, according to phase-contrast microscopy. The spheroid aggregates of pancreatic islet cells and BMSCs showed fortified functions and maintained viability. In conclusion, PECs served as a cell source for pseudo-islets, which were both morphologically and genetically similar to naïve islets. We also suggest a manufacturing method for mixed cellular complexes from 2 different origins that can improve secretion ability and cell differentiation.
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Affiliation(s)
- M K Ju
- Research Institute for Transplantation, Yonsei University Health System, Seoul, South Korea; Department of Transplantation Surgery, Yonsei University Health System, Seoul, South Korea
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Kim JW, Jang JH, Oh MC, Shin JW, Cho DH, Moon JH, Lee JI. FDTD analysis of the light extraction efficiency of OLEDs with a random scattering layer. Opt Express 2014; 22:498-507. [PMID: 24515010 DOI: 10.1364/oe.22.000498] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The light extraction efficiency of OLEDs with a nano-sized random scattering layer (RSL-OLEDs) was analyzed using the Finite Difference Time Domain (FDTD) method. In contrast to periodic diffraction patterns, the presence of an RSL suppresses the spectral shift with respect to the viewing angle. For FDTD simulation of RSL-OLEDs, a planar light source with a certain spatial and temporal coherence was incorporated, and the light extraction efficiency with respect to the fill factor of the RSL and the absorption coefficient of the material was investigated. The design results were compared to the experimental results of the RSL-OLEDs in order to confirm the usefulness of FDTD in predicting experimental results. According to our FDTD simulations, the light confined within the ITO-organic waveguide was quickly absorbed, and the absorption coefficients of ITO and RSL materials should be reduced in order to obtain significant improvement in the external quantum efficiency (EQE). When the extinction coefficient of ITO was 0.01, the EQE in the RSL-OLED was simulated to be enhanced by a factor of 1.8.
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Lee J, Cho H, Koh TW, Yun C, Hofmann S, Lee JH, Kim YH, Lüssem B, Lee JI, Leo K, Gather MC, Yoo S. Enhanced and balanced efficiency of white bi-directional organic light-emitting diodes. Opt Express 2013; 21:28040-28047. [PMID: 24514317 DOI: 10.1364/oe.21.028040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report on the characteristics of enhanced and balanced white-light emission from bi-directional organic light-emitting diodes (BiOLEDs) enabled by the introduction of micro-cavity effects. The insertion of an additional metal layer between the indium tin oxide anode and the hole transporting layer results in similar light output of our BiOLEDs in both top and bottom direction and in reduced distortion of the electroluminescence spectrum. Furthermore, we find that by utilizing MC effects, the overall current efficiency can be improved by 26.2% compared to that of a conventional device.
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Yeo JE, Nam BM, Yang W, Jo YH, Lee S, Nemeno JG, Kiml BY, Koh YG, Lee JI. Fragmin/protamine microparticle carriers as a drug repositioning strategy for cell transplantation. Transplant Proc 2013; 45:3122-6. [PMID: 24157048 DOI: 10.1016/j.transproceed.2013.08.086] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND The importance of drug repositioning has been gaining attention in the last few years, allowing existing pharmaceutical products to be reevaluated for potential alternative therapeutic applications. The purpose of this study was to evaluate the effects of fragmin/protamine microparticles (F/P MPs) on cell aggregates under the concept of drug repositioning. METHODS Mesenchymal stem cells (MSCs) and embryonic rat heart-derived cardiac H9C2 cells were mixed with D-PBS, basal medium, fragmin, protamine, and F/P MPs to manufacture aggregates intended for cell transplantation. To evaluate their adhesive properties as cell carriers, we injected combinations of MSC aggregates into cartilage tissue, observing their leakage from the implantation site. RESULTS Our data demonstrated that MSCs and H9C2 cells mixed with F/P MPs rapidly produced large, viscous cellular aggregates. F/P MPs were bound to the surface of MSCs and H9C2 cells; thus, F/P MPs induced the formation of F/P MP-cell aggregates. Cell aggregates were prevented from leaking from the transplanted site. CONCLUSION Aggregation induced by F/P MPs may improve the efficiency of cell therapy, a novel method for transplantation.
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Affiliation(s)
- J E Yeo
- Regenerative Medicine Laboratory, Center for Stem Cell Research, Department of Biomedical Science and Technology, Institute of Biomedical Science & Technology (IBST), Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul, Republic of Korea; The Center for Stem Cell & Arthritis Research, Department of Orthopedic Surgery, Yonsei Sarang Hospital, Bangbae-dong, Seocho-gu, Seoul 137-060, Republic of Korea
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Kim SI, Kim BH, Chang I, Lee JI, Kim JL, Pradhan AS. Response of six neutron survey meters in mixed fields of fast and thermal neutrons. Radiat Prot Dosimetry 2013; 156:518-524. [PMID: 23620566 DOI: 10.1093/rpd/nct103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Calibration neutron fields have been developed at KAERI (Korea Atomic Energy Research Institute) to study the responses of commonly used neutron survey meters in the presence of fast neutrons of energy around 10 MeV. The neutron fields were produced by using neutrons from the (241)Am-Be sources held in a graphite pile and a DT neutron generator. The spectral details and the ambient dose equivalent rates of the calibration fields were established, and the responses of six neutron survey meters were evaluated. Four single-moderator-based survey meters exhibited an under-responses ranging from ∼9 to 55 %. DINEUTRUN, commonly used in fields around nuclear reactors, exhibited an over-response by a factor of three in the thermal neutron field and an under-response of ∼85 % in the mixed fields. REM-500 (tissue-equivalent proportional counter) exhibited a response close to 1.0 in the fast neutron fields and an under-response of ∼50 % in the thermal neutron field.
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Affiliation(s)
- S I Kim
- Health Physics Dept., Korea Atomic Energy Research Institute, Daeduk-daero 1045, Yuseong, Daejeon, Korea
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Jeon YB, Park KY, Moon JK, Park CH, Choi CH, Lee JI. Dobutamine induced cardiogenic shock due to systolic anterior motion after mitral valve repair. Anaesth Intensive Care 2013; 41:551-552. [PMID: 23808519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
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Kang WG, Choi JH, Jeon EJ, Lee JI, Kim HJ, Kim SK, Kim YD, Lee JH, Ma KJ, Myung SS, So JH. Ultra-low gamma-ray measurement system for neutrinoless double beta decay. Appl Radiat Isot 2013; 81:290-3. [PMID: 23726518 DOI: 10.1016/j.apradiso.2013.03.057] [Citation(s) in RCA: 4] [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] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 03/14/2013] [Indexed: 11/17/2022]
Abstract
An experiment for the detection of 0νβ(+)/EC and 0νEC/EC in 92Mo nuclei has been carried out with a scintillating crystal, CaMoO4, in coincidence with the HPGe detector. We study the background events inside the event selection window for 0ν β(+)/EC decays of CaMoO4 detector. For 51.2 days of data taking period, we didn't observe any event in the neutrinoless EC/EC decay event window. The (92)Mo 0νβ(+)/EC decay half-life limit was set to 0.61×10(20) years with a 90% confidence by method of Feldman and Cousins. This ultra-low gamma ray measurement utilizing coincidence technique can be used for the resonant EC/EC decay process of some nuclei which is potentially important for neutrinoless double beta decay process.
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Affiliation(s)
- W G Kang
- Physics Department, Sejong University, Seoul 143-747, South Korea.
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Lee JI, Jeon WJ, Suh DH, Park JH, Lee JM, Park JW. Reply to Drs Fusetti, Garavaglia and Thébaud. J Hand Surg Eur Vol 2013; 38:577-8. [PMID: 23844419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Moon J, Park JA, Lee SJ, Lee JI, Zyung T, Shin EC, Lee JS. A physicochemical mechanism of chemical gas sensors using an AC analysis. Phys Chem Chem Phys 2013; 15:9361-74. [PMID: 23660648 DOI: 10.1039/c3cp44684k] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electrical modeling of the chemical gas sensors was successfully applied to TiO2 nanofiber gas sensors by developing an equivalent circuit model where the junction capacitance as well as the resistance can be separated from the comparable stray capacitance. The Schottky junction impedance exhibited a characteristic skewed arc described by a Cole-Davidson function, and the variation of the fit and derived parameters with temperature, bias, and NO2 gas concentration indicated definitely a physicochemical sensing mechanism based on the Pt|TiO2 Schottky junctions against the conventional supposition of the enhanced sensitivity in nanostructured gas sensors with high grain boundary/surface area. Analysis on a model Pt|TiO2|Pt structure also confirmed the characteristic impedance response of TiO2 nanofiber sensors.
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Affiliation(s)
- Jaehyun Moon
- OLED Research Center, Electronics and Telecommunications Research Institute, Daejeon 305-350, Korea.
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