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Kumar A, Kim JH, Chang DW. Flexible and Ultra Low Weight Energy Harvesters Based on 2D Phosphorene or Black phosphorus (BP): Current and Futuristic Prospects. ChemSusChem 2024:e202301718. [PMID: 38318655 DOI: 10.1002/cssc.202301718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/02/2024] [Accepted: 02/05/2024] [Indexed: 02/07/2024]
Abstract
Phosphorene, or two-dimensional (2D) black phosphorus, has recently emerged as a competitor of graphene as it offers several advantages, including a tunable band gap, higher on/off current ratio, piezoelectric nature, and biocompatibility. Researchers have succeeded in obtaining several forms of phosphorene, such as nanosheets, nanorods, nanoribbons, and quantum dots, with satisfactory yields. Nanostructures with various controlled properties have been fabricated in multiple devices for energy production. These phosphorene-based devices are lightweight, flexible, and efficient, demonstrating great potential for energy-harvesting applications in sensors and nanogenerators. While ongoing exploration and advancements continue for these lightweight energy harvesters, it is essential to review the current progress in order to develop a future roadmap for the potential use of these phosphorene-based energy harvesters in space programs. They could be employed in applications such as wearable devices for astronauts, where ultralow weight is a vital component of any integrated device. This review also anticipates the growing significance of phosphorene in various emerging applications such as robots, information storage devices, and artificial intelligence.
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Affiliation(s)
- Avneesh Kumar
- Department of Industrial Chemistry and CECS Core Research Institute, Pukyong National University, Busan, 48513, Republic of Korea
| | - Joo Hyun Kim
- Department of Polymer Engineering and CECS Core Research Institute, Pukyong National University, Busan, 48513, Republic of Korea
| | - Dong Wook Chang
- Department of Industrial Chemistry and CECS Core Research Institute, Pukyong National University, Busan, 48513, Republic of Korea
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Kumar A, Chang DW. Optimized Polymeric Membranes for Water Treatment: Fabrication, Morphology, and Performance. Polymers (Basel) 2024; 16:271. [PMID: 38257070 PMCID: PMC10819000 DOI: 10.3390/polym16020271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/24/2024] Open
Abstract
Conventional polymers, endowed with specific functionalities, are extensively utilized for filtering and extracting a diverse set of chemicals, notably metals, from solutions. The main structure of a polymer is an integral part for designing an efficient separating system. However, its chemical functionality further contributes to the selectivity, fabrication process, and resulting product morphology. One example would be a membrane that can be employed to selectively remove a targeted metal ion or chemical from a solution, leaving behind the useful components of the solution. Such membranes or products are highly sought after for purifying polluted water contaminated with toxic and heavy metals. An efficient water-purifying membrane must fulfill several requirements, including a specific morphology attained by the material with a specific chemical functionality and facile fabrication for integration into a purifying module Therefore, the selection of an appropriate polymer and its functionalization become crucial and determining steps. This review highlights the attempts made in functionalizing various polymers (including natural ones) or copolymers with chemical groups decisive for membranes to act as water purifiers. Among these recently developed membrane systems, some of the materials incorporating other macromolecules, e.g., MOFs, COFs, and graphene, have displayed their competence for water treatment. Furthermore, it also summarizes the self-assembly and resulting morphology of the membrane materials as critical for driving the purification mechanism. This comprehensive overview aims to provide readers with a concise and conclusive understanding of these materials for water purification, as well as elucidating further perspectives and challenges.
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Affiliation(s)
| | - Dong Wook Chang
- Department of Industrial Chemistry, ECS Core Research Institute, Pukyong National University, Busan 48513, Republic of Korea;
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Kang Y, Yoon JW, Lee SW, Ahn H, Yun S, Lim J, Lee J, Chang DW, Choi H, Kim BG. Manipulation and Direct Characterization of Polymer/Small-Molecule Interface Morphology in Bulk-Heterojunction Solar Cell. ACS Appl Mater Interfaces 2023. [PMID: 37287192 DOI: 10.1021/acsami.3c05767] [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] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
To investigate the effect of miscibility between conjugated polymers (CPs) and Y6 on bulk-heterojunction (BHJ) type morphology, we propose three different CPs with similar chemical structures but different miscibility with Y6. After selectively removing Y6 from the CP/Y6 blend films, their interface morphology and interlocked dimensions are quantitatively compared using a square-wave model. As CP-Y6 miscibility increases, a higher intermixed interface is formed, providing an enlarged CP-Y6 interface area. Conversely, as the miscibility between CP and Y6 decreases, the height and width of the interlocked dimensions formed by phase separation gradually decrease and increase, respectively. Additionally, when the CP-Y6 interface morphology and electrical properties of the corresponding organic photovoltaic (OPV) device are correlated, as the highly intermixed CP-Y6 interface develops, the exciton dissociation efficiency increases owing to the reduced exciton diffusion length to be dissociated, but the bimolecular recombination tends to deteriorate simultaneously. Furthermore, if the miscibility between CP and Y6 is excessive, the formation of a charge transport pathway through phase separation is interrupted, deteriorating the charge transport capability in BHJ-type OPVs. However, it was confirmed that introducing F atoms into the conjugated backbone of CP can reduce the bimolecular recombination, providing ameliorated light-harvesting efficiency.
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Affiliation(s)
- Yeongkwon Kang
- Department of Organic and Nano System Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Jung Won Yoon
- Department of Chemistry, Research Institute for Natural Science and Research Institute for Convergence of Basic Science, Hanyang University, Seoul 04763, Republic of Korea
| | - Seok Woo Lee
- Department of Industrial Chemistry and CECS Research Institute, Pukyong National University, Busan 48513, Republic of Korea
| | - Hyungju Ahn
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea
| | - Siwon Yun
- Graduate School of Energy Science & Technology, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Jongchul Lim
- Graduate School of Energy Science & Technology, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Jihoon Lee
- Department of Chemistry, Research Institute for Natural Science and Research Institute for Convergence of Basic Science, Hanyang University, Seoul 04763, Republic of Korea
| | - Dong Wook Chang
- Department of Industrial Chemistry and CECS Research Institute, Pukyong National University, Busan 48513, Republic of Korea
| | - Hyosung Choi
- Department of Chemistry, Research Institute for Natural Science and Research Institute for Convergence of Basic Science, Hanyang University, Seoul 04763, Republic of Korea
| | - Bong-Gi Kim
- Department of Organic and Nano System Engineering, Konkuk University, Seoul 05029, Republic of Korea
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Kumar A, Chang DW. Towards the Future of Polymeric Hybrids of Two-Dimensional Black Phosphorus or Phosphorene: From Energy to Biological Applications. Polymers (Basel) 2023; 15:polym15040947. [PMID: 36850230 PMCID: PMC9962990 DOI: 10.3390/polym15040947] [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: 01/18/2023] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
With the advent of a new 2D nanomaterial, namely, black phosphorus (BP) or phosphorene, the scientific community is now dedicated to focusing on and exploring this 2D material offering elusive properties such as a higher carrier mobility, biocompatibility, thickness-dependent band gap, and optoelectronic characteristics that can be harnessed for multiple applications, e.g., nanofillers, energy storage devices, field effect transistors, in water disinfection, and in biomedical sciences. The hexagonal ring of phosphorus atoms in phosphorene is twisted slightly, unlike how it is in graphene. Its unique characteristics, such as a high carrier mobility, anisotropic nature, and biocompatibility, have attracted much attention and generated further scientific curiosity. However, despite these interesting features, the phosphorene or BP poses challenges and causes frustrations when it comes to its stability under ambient conditions and processability, and thus in order to overcome these hurdles, it must be conjugated or linked with the suitable and functional organic counter macromolecule in such a way that its properties are not compromised while providing a protection from air/water that can otherwise degrade it to oxides and acid. The resulting composites/hybrid system of phosphorene and a macromolecule, e.g., a polymer, can outperform and be exploited for the aforementioned applications. These assemblies of a polymer and phosphorene have the potential for shifting the paradigm from exhaustively used graphene to new commercialized products offering multiple applications.
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Lee SW, Hussain MW, Lee J, Whang DR, Jeong WH, Choi H, Chang DW. Effect of Chlorine Substituents on the Photovoltaic Properties of Monocyanated Quinoxaline-Based D-A-Type Polymers. ACS Appl Mater Interfaces 2023; 15:5547-5555. [PMID: 36688562 DOI: 10.1021/acsami.2c19702] [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: 06/17/2023]
Abstract
A string of monocyanated quinoxaline (Qx)-based D-A-type polymers systematically decorated with electron-attracting chlorine (Cl) atoms was created for use in non-fullerene polymer solar cells (PSCs). First, coupling of the benzodithiophene (BDT) donor and Qx acceptor with the strong electron-attracting cyano (CN) unit at its 5-position yielded the monocyanated reference polymer PB-CNQ. Subsequently, the additional Cl atoms were separately or simultaneously incorporated into the thiophene side groups of the BDT donor and Qx acceptor to create other objective polymers, PBCl-CNQ, PB-CNQCl, and PBCl-CNQCl. The Cl substituents on the BDT donor and Qx acceptor are represented by the names of the polymers. Owing to the favorable contributions of Cl substituents, the inverted-type non-fullerene PSCs based on partially chlorinated PBCl-CNQ (12.80%) and PB-CNQCl (13.93%) exhibited better power conversion efficiencies (PCEs) than the device based on unchlorinated reference PB-CNQ (11.19%). However, a significantly reduced PCE of 9.84% was observed for the device based on PBCl-CNQCl, in which Cl atoms were loaded on both the BDT donor and Qx acceptor at the same time. Hence, these results reveal that optimization of the number and position of Cl substituents in monocyanated Qx-based polymers is essential for enhancing their photovoltaic nature through the synergistic effects between two strong electron-attracting CN and Cl substituents.
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Affiliation(s)
- Seok Woo Lee
- Department of Industrial Chemistry, Pukyong National University, 48513 Busan, Republic of Korea
- CECS Research Institute, Core Research Institute, 48513 Busan, Republic of Korea
| | - Md Waseem Hussain
- Department of Chemistry, Research Institute for Natural Science and Research Institute for Convergence of Basic Science, Hanyang University, 04730 Seoul, Republic of Korea
| | - Jihoon Lee
- Department of Chemistry, Research Institute for Natural Science and Research Institute for Convergence of Basic Science, Hanyang University, 04730 Seoul, Republic of Korea
| | - Dong Ryeol Whang
- Department of Advanced Materials, Hannam University, 34054 Daejeon, Republic of Korea
| | - Woo Hyeon Jeong
- Department of Chemistry, Research Institute for Natural Science and Research Institute for Convergence of Basic Science, Hanyang University, 04730 Seoul, Republic of Korea
| | - Hyosung Choi
- Department of Chemistry, Research Institute for Natural Science and Research Institute for Convergence of Basic Science, Hanyang University, 04730 Seoul, Republic of Korea
| | - Dong Wook Chang
- Department of Industrial Chemistry, Pukyong National University, 48513 Busan, Republic of Korea
- CECS Research Institute, Core Research Institute, 48513 Busan, Republic of Korea
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Kumar A, Chang DW. Proton Conducting Membranes with Molecular Self Assemblies and Ionic Channels for Efficient Proton Conduction. Membranes (Basel) 2022; 12:1174. [PMID: 36557081 PMCID: PMC9781519 DOI: 10.3390/membranes12121174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 06/17/2023]
Abstract
Supramolecular assemblies are vital for biological systems. This phenomenon in artificial materials is directly related to their numerous properties and their performance. Here, a simple approach to supramolecular assemblies is employed to fabricate highly efficient proton conducting molecular wires for fuel cell applications. Small molecule-based molecular assembly leading to a discotic columnar architecture is achieved, simultaneously with proton conduction that can take place efficiently in the absence of water, which otherwise is very difficult to obtain in interconnected ionic channels. High boiling point proton facilitators are incorporated into these columns possessing central ionic channels, thereby increasing the conduction multifold. Larger and asymmetrical proton facilitators disintegrated the self-assembly, resulting in low proton conduction efficiency. The highest conductivity was found to be approaching 10-2 S/cm for the molecular wires in an anhydrous state, which is ascribed to the continuous network of hydrogen bonds in which protons can hop between with a lower energy barrier. The molecular wires with ionic channels presented here have potential as an alternative to proton conductors operating under anhydrous conditions at both low and high temperatures.
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Nugraha DF, Son DH, Wardani RP, Lee SW, Whang DR, Kim JH, Chang DW. Strategic structural evolution for enhancing the photovoltaic performance of quinoxaline-based polymers. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2022.07.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lee SW, Shin HJ, Park B, Shome S, Whang DR, Bae H, Chung S, Cho K, Ko SJ, Choi H, Chang DW. Effect of Electron-Withdrawing Chlorine Substituent on Morphological and Photovoltaic Properties of All Chlorinated D-A-Type Quinoxaline-Based Polymers. ACS Appl Mater Interfaces 2022; 14:19785-19794. [PMID: 35420778 DOI: 10.1021/acsami.2c00764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The choice of the chlorine (Cl) atom as an electron-withdrawing substituent in conjugated polymers leads to a higher potential in the commercialization of polymer solar cells than its fluorine counterpart because of the versatility and cost-effectiveness of the chlorination process. In addition, the population and location of Cl substituents can significantly influence the photovoltaic characteristics of polymers. In this study, three chlorinated quinoxaline-based polymers were invented to examine the numerical and positioning effects of the Cl atom on their photovoltaic characteristics. The number of Cl substituents in the reference polymer, PBCl-Qx, was adjusted to three: two Cl atoms in the benzodithiophene-type D unit and one Cl atom in the quinoxaline-type A unit. Subsequently, two more Cl atoms were selectively introduced at the 4- and 5-positions of the alkylated thiophene moieties at the 2,3-positions of the quinoxaline moiety in PBCl-Qx to obtain the additional polymers PBCl-Qx4Cl and PBCl-Qx5Cl, respectively. The conventional PBCl-Qx4Cl device exhibited a better power conversion efficiency (PCE) of 12.95% as compared to those of PBCl-Qx (12.44%) and PBCl-Qx5Cl (11.82%) devices. The highest PCE of the device with PBCl-Qx4Cl was ascribed to an enhancement in the open-circuit voltage and fill factor induced by the deeper energy level of the highest occupied molecular orbital and the favorable morphological features in its blended film with Y6.
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Affiliation(s)
- Seok Woo Lee
- Department of Industrial Chemistry, Pukyong National University, 48513 Busan, Republic of Korea
| | - Hee Jeong Shin
- Department of Chemistry, Research Institute for Natural Science and Institute of Nano Science and Technology, Hanyang University, 04730 Seoul, Republic of Korea
| | - Byoungwook Park
- Division of Advanced Materials, Korea Research Institute of Chemical Technology (KRICT), Daejeon 34113, Republic of Korea
| | - Sanchari Shome
- Department of Chemistry, Research Institute for Natural Science and Institute of Nano Science and Technology, Hanyang University, 04730 Seoul, Republic of Korea
| | - Dong Ryeol Whang
- Department of Advanced Materials, Hannam University, Daejeon 34054, Republic of Korea
| | - Hyemin Bae
- Division of Advanced Materials, Korea Research Institute of Chemical Technology (KRICT), Daejeon 34113, Republic of Korea
| | - Sein Chung
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 37673 Gyeongbuk, Republic of Korea
| | - Kilwon Cho
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 37673 Gyeongbuk, Republic of Korea
| | - Seo-Jin Ko
- Division of Advanced Materials, Korea Research Institute of Chemical Technology (KRICT), Daejeon 34113, Republic of Korea
| | - Hyosung Choi
- Department of Chemistry, Research Institute for Natural Science and Institute of Nano Science and Technology, Hanyang University, 04730 Seoul, Republic of Korea
| | - Dong Wook Chang
- Department of Industrial Chemistry, Pukyong National University, 48513 Busan, Republic of Korea
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Lee SW, Hussain MDW, Shome S, Ha SR, Oh JT, Whang DR, Kim Y, Kim DY, Choi H, Chang DW. Effect of electron-withdrawing fluorine and cyano substituents on photovoltaic properties of two-dimensional quinoxaline-based polymers. Sci Rep 2021; 11:24381. [PMID: 34934136 PMCID: PMC8692587 DOI: 10.1038/s41598-021-03763-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 12/07/2021] [Indexed: 11/23/2022] Open
Abstract
In this study, strong electron-withdrawing fluorine (F) and cyano (CN) substituents are selectively incorporated into the quinoxaline unit of two-dimensional (2D) D-A-type polymers to investigate their effects on the photovoltaic properties of the polymers. To construct the 2D polymeric structure, electron-donating benzodithiophene and methoxy-substituted triphenylamine are directly linked to the horizontal and vertical directions of the quinoxaline acceptor, respectively. After analyzing the structural, optical, and electrochemical properties of the resultant F- and CN-substituted polymers, labeled as PBCl-MTQF and PBCl-MTQCN, respectively, inverted-type polymer solar cells with a non-fullerene Y6 acceptor are fabricated to investigate the photovoltaic performances of the polymers. It is discovered that the maximum power conversion efficiency of PBCl-MTQF is 7.48%, whereas that of PBCl-MTQCN is limited to 3.52%. This significantly reduced PCE of the device based on PBCl-MTQCN is ascribed to the formation of irregular, large aggregates in the active layer, which can readily aggravate the charge recombination and charge transport kinetics of the device. Therefore, the photovoltaic performance of 2D quinoxaline-based D-A-type polymers is significantly affected by the type of electron-withdrawing substituent.
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Affiliation(s)
- Seok Woo Lee
- Department of Industrial Chemistry, Pukyong National University, 48513, Busan, Republic of Korea
| | - M D Waseem Hussain
- Department of Chemistry, Research Institute for Natural Science and Institute of Nano Science and Technology, Hanyang University, 04730, Seoul, Republic of Korea
| | - Sanchari Shome
- Department of Chemistry, Research Institute for Natural Science and Institute of Nano Science and Technology, Hanyang University, 04730, Seoul, Republic of Korea
| | - Su Ryong Ha
- Department of Chemistry, Research Institute for Natural Science and Institute of Nano Science and Technology, Hanyang University, 04730, Seoul, Republic of Korea
| | - Jae Taek Oh
- Department of Chemistry, Research Institute for Natural Science and Institute of Nano Science and Technology, Hanyang University, 04730, Seoul, Republic of Korea
| | - Dong Ryeol Whang
- Department of Advanced Materials, Hannam University, Daejeon, 34054, Republic of Korea
| | - Yunseul Kim
- School of Materials Science and Engineering (SMSE), Research Institute of Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Dong-Yu Kim
- School of Materials Science and Engineering (SMSE), Research Institute of Solar and Sustainable Energies (RISE), Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Hyosung Choi
- Department of Chemistry, Research Institute for Natural Science and Institute of Nano Science and Technology, Hanyang University, 04730, Seoul, Republic of Korea.
| | - Dong Wook Chang
- Department of Industrial Chemistry, Pukyong National University, 48513, Busan, Republic of Korea.
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Handoko SL, Jin HC, Whang DR, Kim JH, Chang DW. Effect of cyano substituent on photovoltaic properties of quinoxaline-based polymers. J IND ENG CHEM 2020. [DOI: 10.1016/j.jiec.2020.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Kim JT, Jin HC, Putri SK, Whang DR, Kim JH, Chang DW. Synthesis of Quinoxaline-Based Small Molecules Possessing Multiple Electron-Withdrawing Moieties for Photovoltaic Applications. Macromol Res 2019. [DOI: 10.1007/s13233-020-8002-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Handoko SL, Jin HC, Whang DR, Putri SK, Kim JH, Chang DW. Synthesis of quinoxaline-based polymers with multiple electron-withdrawing groups for polymer solar cells. J IND ENG CHEM 2019. [DOI: 10.1016/j.jiec.2019.01.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Yang MH, Jin HC, Kim JH, Chang DW. Synthesis of Cyano-Substituted Conjugated Polymers for Photovoltaic Applications. Polymers (Basel) 2019; 11:E746. [PMID: 31027365 PMCID: PMC6571826 DOI: 10.3390/polym11050746] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 04/19/2019] [Accepted: 04/22/2019] [Indexed: 11/16/2022] Open
Abstract
Three conjugated polymers, in which the electron-donating (D) 5-alkylthiophene-2-yl-substitued benzodithiophene was linked to three different electron-accepting (A) moieties, i.e., benzothiadiazole (BT), diphenylquinoxaline (DPQ), and dibenzophenazine (DBP) derivative via thiophene bridge, were synthesized using the Stille coupling reaction. In particular, the strong electron-withdrawing cyano (CN) group was incorporated into the A units BT, DPQ, and DBP to afford three D-A type target polymers PB-BTCN, PB-DPQCN, and PB-DBPCN, respectively. Owing to the significant contribution of the CN-substituent, these polymers exhibit not only low-lying energy levels of both the highest occupied molecular orbital and the lowest unoccupied molecular orbital, but also reduced bandgaps. Furthermore, to investigate the photovoltaic properties of polymers, inverted-type devices with the structure of ITO/ZnO/Polymer:PC71BM/MoO3/Ag were fabricated and analyzed. All the polymer solar cells based on the three cyano-substituted conjugated polymers showed high open-circuit voltages (Voc) greater than 0.89 V, and the highest power conversion efficiency of 4.59% was obtained from the device based on PB-BtCN with a Voc of 0.93 V, short-circuit current of 7.36 mA cm-2, and fill factor of 67.1%.
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Affiliation(s)
- Mun Ho Yang
- Department of Industrial Chemistry, Pukyong National University, Pusan 48513, Korea.
| | - Ho Cheol Jin
- Department of Polymer Engineering, Pukyong National University, Pusan 48513, Korea.
| | - Joo Hyun Kim
- Department of Polymer Engineering, Pukyong National University, Pusan 48513, Korea.
| | - Dong Wook Chang
- Department of Industrial Chemistry, Pukyong National University, Pusan 48513, Korea.
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Daruwalla K, Olivero N, Pluger A, Rao S, Chang DW, Simoni M. A quantitative analysis of the performance of computing architectures used in neural simulations. J Neurosci Methods 2019; 311:57-66. [PMID: 30291861 DOI: 10.1016/j.jneumeth.2018.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 09/28/2018] [Accepted: 10/02/2018] [Indexed: 11/24/2022]
Abstract
BACKGROUND Numerical solutions of neuron models are helping neuroscientists gain new insights into the behavior of neural systems. Although computing power is increasing, the complexity of the systems being simulated is also increasing. If the computation is not well matched to the computing hardware, simulations can take lengthy times to run, which can make it more difficult to draw inferences from those simulations and also to use them in feedback with living neurons such as in the dynamic clamp. NEW METHOD In this paper, we perform a quantitative analysis to get a better sense of how much impact the hardware architectures can have on simulation performance. Three different architectures are implemented on the same hardware platform and compared with respect to simulation time, error, and resources used. RESULTS The results indicate that a lookup table approach to evaluate functions can decrease simulation time by orders of magnitude with respect to the traditional approach of mathematical operations. COMPARISON WITH EXISTING METHOD(S) There are many different ways to implement a lookup table approach to evaluate a function. The method presented in this paper sacrifices some speed for greater generality and accuracy with respect to other published methods. CONCLUSIONS Lookup tables with 32 interpolation points can dramatically speed up computation time of neural simulations without adding significant error. In this paper linear interpolation was used, but higher order interpolation could be used to further reduce simulation time.
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Affiliation(s)
- K Daruwalla
- Rose-Hulman Institute of Technology, 5500 Wabash Ave., Terre Haute, IN 47803, USA
| | - N Olivero
- Rose-Hulman Institute of Technology, 5500 Wabash Ave., Terre Haute, IN 47803, USA
| | - A Pluger
- Rose-Hulman Institute of Technology, 5500 Wabash Ave., Terre Haute, IN 47803, USA
| | - S Rao
- Rose-Hulman Institute of Technology, 5500 Wabash Ave., Terre Haute, IN 47803, USA
| | - D W Chang
- Rose-Hulman Institute of Technology, 5500 Wabash Ave., Terre Haute, IN 47803, USA.
| | - M Simoni
- Rose-Hulman Institute of Technology, 5500 Wabash Ave., Terre Haute, IN 47803, USA.
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Putri SK, Kim YH, Whang DR, Kim JH, Chang DW. Macromol. Rapid Commun. 16/2018. Macromol Rapid Commun 2018. [DOI: 10.1002/marc.201870037] [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: 11/10/2022]
Affiliation(s)
- Sella Kurnia Putri
- Department of Industrial Chemistry; Pukyong National University; Pusan 48547 Republic of Korea
| | - Yun Hwan Kim
- Department of Polymer Engineering; Pukyong National University; Pusan 48547 Republic of Korea
| | - Dong Ryeol Whang
- Linz Institute for Organic Solar Cells/Institute of Physical Chemistry; Johannes Kepler University; Linz 4040 Austria
| | - Joo Hyun Kim
- Department of Polymer Engineering; Pukyong National University; Pusan 48547 Republic of Korea
| | - Dong Wook Chang
- Department of Industrial Chemistry; Pukyong National University; Pusan 48547 Republic of Korea
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Putri SK, Kim YH, Whang DR, Kim JH, Chang DW. Synthesis of Trifluoromethylated Quinoxaline-Based Polymers for Photovoltaic Applications. Macromol Rapid Commun 2018; 39:e1800260. [PMID: 29974539 DOI: 10.1002/marc.201800260] [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] [Received: 04/04/2018] [Revised: 05/16/2018] [Indexed: 11/09/2022]
Abstract
A series of quinoxaline-based conjugated polymers, in which the electron-donating benzodithiophene (BDT) unit is linked to the electron-accepting 6,7-difluorinated quinoxaline (DFQ) derivatives by a thiophene bridge, is synthesized. To investigate their effects on the intrinsic properties of polymers, strong electron-withdrawing trifluoromethyl (CF3 ) groups were incorporated into the meta-position of the phenyl ring at the 2,3-positions of the DFQ unit of the reference polymer, labelled PEhB-FQx, to yield the target polymer PEhB-FQxCF3. In addition, the 2-ethylhexyloxy substituents on the BDT donor in PEhB-FQxCF3 are changed to the more planar 2-ethylhexyl thiophene units to produce another target polymer PThB-FQxCF3. Owing to the significant contributions of the CF3 moiety, PEhB-FQxCF3 exhibits quite discernible optical and electrochemical properties along with significant enhancement in photovoltaic performances compared to the reference polymer PEhB-FQx. Furthermore, the incorporation of the alkylthienyl side chains on the BDT moiety confers on the resultant PThB-FQxCF3 to possess the maximum power conversion efficiency of 7.26% with an open circuit voltage of 0.88 V, short-circuit current density of 12.20 mA cm-2 , and fill factor of 67.80%.
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Affiliation(s)
- Sella Kurnia Putri
- Department of Industrial Chemistry, Pukyong National University, Pusan, 48547, Republic of Korea
| | - Yun Hwan Kim
- Department of Polymer Engineering, Pukyong National University, Pusan, 48547, Republic of Korea
| | - Dong Ryeol Whang
- Linz Institute for Organic Solar Cells/Institute of Physical Chemistry, Johannes Kepler University, Linz, 4040, Austria
| | - Joo Hyun Kim
- Department of Polymer Engineering, Pukyong National University, Pusan, 48547, Republic of Korea
| | - Dong Wook Chang
- Department of Industrial Chemistry, Pukyong National University, Pusan, 48547, Republic of Korea
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Jin CH, Putri SK, Chang DW, Lee J. Influence of Acceptor Units with the Trifluoromethyl Group on Charge Transport in Donor‐Acceptor Semiconducting Copolymer Films. J Imaging Sci Technol 2018. [DOI: 10.2352/j.imagingsci.technol.2018.62.4.040404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Zhang Y, Zhang L, Li R, Chang DW, Ye Y, Minna JD, Roth JA, Han B, Wu X. Genetic variations in cancer-related significantly mutated genes and lung cancer susceptibility. Ann Oncol 2018; 28:1625-1630. [PMID: 28383694 DOI: 10.1093/annonc/mdx161] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [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: 12/09/2016] [Indexed: 12/13/2022] Open
Abstract
Background Cancer initiation and development are driven by key mutations in driver genes. Applying high-throughput sequencing technologies and bioinformatic analyses, The Cancer Genome Atlas (TCGA) project has identified panels of somatic mutations that contributed to the etiology of various cancers. However, there are few studies investigating the germline genetic variations in these significantly mutated genes (SMGs) and lung cancer susceptibility. Patients and methods We comprehensively evaluated 1655 tagged single nucleotide polymorphisms (SNPs) located in 127 SMGs identified by TCGA, and test their association with lung cancer risk in large-scale case-control study. Functional effect of the validated SNPs, gene mutation frequency and pathways were analyzed. Results We found 11 SNPs in 8 genes showed consistent association (P < 0.1) and 8 SNPs significantly associated with lung cancer risk (P < 0.05) in both discovery and validation phases. The most significant association was rs10412613 in PPP2R1A, with the minor G allele associated with a decreased risk of lung cancer [odds ratio = 0.91, 95% confidence interval (CI): 0.87-0.96, P = 2.3 × 10-4]. Cumulative analysis of risk score built as a weight sum of the 11 SNPs showed consistently elevated risk with increasing risk score (P for trend = 9.5 × 10-9). In stratified analyses, the association of PPP2R1A:rs10412613 and lung cancer risk appeared stronger among population of younger age at diagnosis and never smokers. The expression quantitative trait loci analysis indicated that rs10412613, rs10804682, rs635469 and rs6742399 genotypes significantly correlated with the expression of PPP2R1A, ATR, SETBP1 and ERBB4, respectively. From TCGA data, expression of the identified genes was significantly different in lung tumors compared with normal tissues, and the genes' highest mutation frequency was found in lung cancers. Integrative pathway analysis indicated the identified genes were mainly involved in AKT/NF-κB regulatory pathway suggesting the underlying biological processes. Conclusion This study revealed novel genetic variants in SMGs associated with lung cancer risk, which might contribute to elucidating the biological network involved in lung cancer development.
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Affiliation(s)
- Y Zhang
- Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, USA.,Department of Pulmonary Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - L Zhang
- Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, USA
| | - R Li
- Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, USA.,Department of Pulmonary Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - D W Chang
- Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, USA
| | - Y Ye
- Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, USA
| | - J D Minna
- Harmon Center for Therapeutic Oncology, University of Texas Southwestern Medical Center, Dallas
| | - J A Roth
- Department of Thoracic & Cardiovascular Surgery, University of Texas MD Anderson Cancer Center, Houston, USA
| | - B Han
- Department of Pulmonary Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - X Wu
- Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, USA
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Affiliation(s)
- Dong Wook Chang
- Department of Industrial Chemistry; Pukyung National University; 365 Sinseon-ro Busan 608-739 South Korea
| | - Jong-Beom Baek
- School of Energy and Chemical Engineering/Low-Dimensional Carbon Materials Center; Ulsan National University of Science and Technology (UNIST); 100 Banyeon Ulsan 689-798 South Korea
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21
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Oh JY, Chang DW, Lee HJ. Co-Sensitized Mesoporous TiO2Solar Cells: Hybrid Sensitizer of SILAR-Grown CdS Quantum Dot (QD) and Molecular Dye (Z907) with a Metal Oxide Interlayer. B KOREAN CHEM SOC 2013. [DOI: 10.5012/bkcs.2013.34.11.3183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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22
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Chang DW, Lee EK, Park EY, Yu H, Choi HJ, Jeon IY, Sohn GJ, Shin D, Park N, Oh JH, Dai L, Baek JB. Nitrogen-Doped Graphene Nanoplatelets from Simple Solution Edge-Functionalization for n-Type Field-Effect Transistors. J Am Chem Soc 2013; 135:8981-8. [DOI: 10.1021/ja402555n] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Dong Wook Chang
- Department of Chemical Systematic
Engineering, Catholic University of Daegu, 100, Hayang, 712-702, South Korea
| | - Eun Kwang Lee
- School of Nano-Bioscience and
Chemical Engineering, KIER-UNIST Advanced Center for Energy, Low-Dimensional
Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South
Korea
| | - Eun Yeob Park
- School of Nano-Bioscience and
Chemical Engineering, KIER-UNIST Advanced Center for Energy, Low-Dimensional
Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South
Korea
| | - Hojeong Yu
- School of Nano-Bioscience and
Chemical Engineering, KIER-UNIST Advanced Center for Energy, Low-Dimensional
Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South
Korea
| | - Hyun-Jung Choi
- Interdisciplinary School
of Green
Energy, Low-Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South Korea
| | - In-Yup Jeon
- Interdisciplinary School
of Green
Energy, Low-Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South Korea
| | - Gyung-Joo Sohn
- Interdisciplinary School
of Green
Energy, Low-Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South Korea
| | - Dongbin Shin
- Interdisciplinary School
of Green
Energy, Low-Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South Korea
| | - Noejung Park
- Interdisciplinary School
of Green
Energy, Low-Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South Korea
| | - Joon Hak Oh
- School of Nano-Bioscience and
Chemical Engineering, KIER-UNIST Advanced Center for Energy, Low-Dimensional
Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South
Korea
| | - Liming Dai
- Department of Macromolecular
Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Jong-Beom Baek
- Interdisciplinary School
of Green
Energy, Low-Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South Korea
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Affiliation(s)
- Dong Wook Chang
- Department of Chemical Systematic Engineering; Catholic University of Daegu; 13-13 Hayang, Gyeongbuk; 712-702; South Korea
| | - Hyun-Jung Choi
- Interdisciplinary School of Green Energy/Low-Dimensional Carbon Materials Center; Ulsan National University of Science and Technology (UNIST); 100, Banyeon; Ulsan; 689-798; South Korea
| | - In-Yup Jeon
- Interdisciplinary School of Green Energy/Low-Dimensional Carbon Materials Center; Ulsan National University of Science and Technology (UNIST); 100, Banyeon; Ulsan; 689-798; South Korea
| | - Jong-Beom Baek
- Interdisciplinary School of Green Energy/Low-Dimensional Carbon Materials Center; Ulsan National University of Science and Technology (UNIST); 100, Banyeon; Ulsan; 689-798; South Korea
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Wook Chang D, Bae SY, Dai L, Baek JB. Efficient energy transfer between amphiphilic dendrimers with oligo(p-phenylenevinylene) core branches and oligo(ethylene oxide) termini in micelles. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/pola.26356] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Abstract
Historically, the reported incidence of upper extremity lymphedema in breast cancer survivors who have undergone axillary lymph node dissection has ranged from 9% to 41%. In the past 2 decades, sentinel lymph node biopsy has become popular as a way to minimize the morbidity associated with axillary dissection without compromising the cure rate for breast cancer patients. However, even with sentinel node biopsy, the postoperative incidence of upper limb lymphedema in breast cancer patients remains at 4-10%. Lymphedema occasionally emerges immediately after surgery but most often appears after a latent period. Obesity, postoperative seroma, and radiation therapy have been reported as major risk factors for upper extremity lymphedema, but the etiology of lymphedema is still not fully understood. Common symptoms of upper limb lymphedema are increased volume and weight of the affected limb and increased skin tension. The increased volume of the affected limb not only causes physical impairments in wearing clothes and in dexterity but also affects patients' emotional and mental status. Surgical management of lymphedema can be broadly categorized into physiologic methods and reductive techniques. Physiologic methods such as flap interposition, lymph node transfers, and lymphatic bypass procedures aim to decrease lymphedema by restoring lymphatic drainage. In contrast, reductive techniques such as direct excision or liposuction aim to remove fibrofatty tissue generated as a consequence of sustained lymphatic fluid stasis. Currently, microsurgical variations of lymphatic bypass, in which excess lymph trapped within the lymphedematous limb is redirected into other lymphatic basins or into the venous circulation, have gained popularity.
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Affiliation(s)
- D W Chang
- Department of Plastic Surgery, The University of Texas, MD Anderson Cancer Center, Houston, TX 77030, USA.
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Sohn GJ, Choi HJ, Jeon IY, Chang DW, Dai L, Baek JB. Water-dispersible, sulfonated hyperbranched poly(ether-ketone) grafted multiwalled carbon nanotubes as oxygen reduction catalysts. ACS Nano 2012; 6:6345-6355. [PMID: 22680297 DOI: 10.1021/nn301863d] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
To endorse sufficient water affinity to multiwalled carbon nanotubes (MWCNTs), dendritic hyperbranched poly(ether-ketone) (HPEK) was first covalently grafted to the surface of a MWCNT via a Friedel-Crafts acylation reaction. The resultant HPEK-grafted MWCNT (HPEK-g-MWCNT) was subsequently sulfonated in chlorosulfonic acid to produce sulfonated HPEK-g-MWCNT (SHPEK-g-MWCNT), which is dispersible well in water showing a zeta potential value of -57.8 mV. The SHPEK-g-MWCNT paper simply formed by filtration of aqueous dispersion has a sheet resistance as low as 63 Ω/sq. Its thin film shows a high electrocatalytic activity for oxygen reduction reaction (ORR). Thus, the newly produced water-dispersible MWCNT is a new class of high performance cathode material for ORR.
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Affiliation(s)
- Gyung-Joo Sohn
- Interdisciplinary School of Green Energy/Low-Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology, 100 Banyeon, Ulsan 689-798, South Korea
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Dai L, Chang DW, Baek JB, Lu W. Carbon nanomaterials for advanced energy conversion and storage. Small 2012; 8:1130-66. [PMID: 22383334 DOI: 10.1002/smll.201101594] [Citation(s) in RCA: 550] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2011] [Revised: 11/03/2011] [Indexed: 05/19/2023]
Abstract
It is estimated that the world will need to double its energy supply by 2050. Nanotechnology has opened up new frontiers in materials science and engineering to meet this challenge by creating new materials, particularly carbon nanomaterials, for efficient energy conversion and storage. Comparing to conventional energy materials, carbon nanomaterials possess unique size-/surface-dependent (e.g., morphological, electrical, optical, and mechanical) properties useful for enhancing the energy-conversion and storage performances. During the past 25 years or so, therefore, considerable efforts have been made to utilize the unique properties of carbon nanomaterials, including fullerenes, carbon nanotubes, and graphene, as energy materials, and tremendous progress has been achieved in developing high-performance energy conversion (e.g., solar cells and fuel cells) and storage (e.g., supercapacitors and batteries) devices. This article reviews progress in the research and development of carbon nanomaterials during the past twenty years or so for advanced energy conversion and storage, along with some discussions on challenges and perspectives in this exciting field.
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Affiliation(s)
- Liming Dai
- Center of Advanced Science and Engineering for Carbon, Case4Carbon, Department of Macromolecular Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
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Wang S, Zhang L, Xia Z, Roy A, Chang DW, Baek JB, Dai L. BCN Graphene as Efficient Metal-Free Electrocatalyst for the Oxygen Reduction Reaction. Angew Chem Int Ed Engl 2012; 51:4209-12. [DOI: 10.1002/anie.201109257] [Citation(s) in RCA: 1022] [Impact Index Per Article: 85.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Indexed: 11/11/2022]
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Wang S, Zhang L, Xia Z, Roy A, Chang DW, Baek JB, Dai L. BCN Graphene as Efficient Metal-Free Electrocatalyst for the Oxygen Reduction Reaction. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201109257] [Citation(s) in RCA: 159] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Kumar NA, Choi HJ, Shin YR, Chang DW, Dai L, Baek JB. Polyaniline-grafted reduced graphene oxide for efficient electrochemical supercapacitors. ACS Nano 2012; 6:1715-23. [PMID: 22276770 DOI: 10.1021/nn204688c] [Citation(s) in RCA: 352] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
An alternative and effective route to prepare conducting polyaniline-grafted reduced graphene oxide (PANi-g-rGO) composite with highly enhanced properties is reported. In order to prepare PANi-g-rGO, amine-protected 4-aminophenol was initially grafted to graphite oxide (GO) via acyl chemistry where a concomitant partial reduction of GO occurred due to the refluxing and exposure of GO to thionyl chloride vapors and heating. Following the deprotection of amine groups, an in situ chemical oxidative grafting of aniline in the presence of an oxidizing agent was carried out to yield highly conducting PANi-g-rGO. Electron microscopic studies demonstrated that the resultant composite has fibrillar morphology with a room-temperature electrical conductivity as high as 8.66 S/cm and capacitance of 250 F/g with good cycling stability.
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Affiliation(s)
- Nanjundan Ashok Kumar
- Interdisciplinary School of Green Energy/Institute of Advanced Materials & Devices, Ulsan National Institute of Science and Technology (UNIST), 100, Banyeon, Ulsan 689-798, South Korea
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Chang DW, Tsao HN, Salvatori P, De Angelis F, Grätzel M, Park SM, Dai L, Lee HJ, Baek JB, Nazeeruddin MK. Bistriphenylamine-based organic sensitizers with high molar extinction coefficients for dye-sensitized solar cells. RSC Adv 2012. [DOI: 10.1039/c2ra20798b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Chang DW, Choi HJ, Jung SM, Dai L, Baek JB. Large clusters and hollow microfibers by multicomponent self-assembly of citrate stabilized gold nanoparticles with temperature-responsive amphiphilic dendrimers. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm31273e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Chang DW, Ko SJ, Kim JY, Park SM, Lee HJ, Dai L, Baek JB. Multifunctional Conjugated Polymers with Main-Chain Donors and Side-Chain Acceptors for Dye Sensitized Solar Cells (DSSCs) and Organic Photovoltaic Cells (OPVs). Macromol Rapid Commun 2011; 32:1809-14. [DOI: 10.1002/marc.201100447] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 07/31/2011] [Indexed: 11/07/2022]
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Wang S, Yu D, Dai L, Chang DW, Baek JB. Polyelectrolyte-functionalized graphene as metal-free electrocatalysts for oxygen reduction. ACS Nano 2011; 5:6202-9. [PMID: 21780760 DOI: 10.1021/nn200879h] [Citation(s) in RCA: 238] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Poly(diallyldimethylammonium chloride), PDDA, was used as an electron acceptor for functionalizing graphene to impart electrocatalytic activity for the oxygen reduction reaction (ORR) in fuel cells. Raman and X-ray photoelectron spectroscopic measurements indicate the charge transfer from graphene to PDDA. The resultant graphene positively charged via intermolecular charge-transfer with PDDA was demonstrated to show remarkable electrocatalytic activity toward ORR with better fuel selectivity, tolerance to CO posing, and long-term stability than that of the commercially available Pt/C electrode. The observed ORR electrocatalytic activity induced by the intermolecular charge-transfer provides a general approach to various carbon-based metal-free ORR catalysts for oxygen reduction.
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Affiliation(s)
- Shuangyin Wang
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Abstract
Novel quinoxaline-based organic sensitizers using vertical (RC-21) and horizontal (RC-22) conjugation between an electron-donating triphenylamine unit and electron-accepting quinoxaline unit have been synthesized and used for dye-sensitized solar cells (DSSCs), leading to the relatively high power conversion efficiencies of 3.30 and 5.56% for RC-21 and RC-22, respectively. This result indicates that the quinoxaline electron-accepting unit is quite a promising candidate in organic sensitizers.
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Affiliation(s)
- Dong Wook Chang
- Interdisciplinary School of Green Energy/Institute of Advanced Materials and Devices, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, South Korea
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Abstract
We describe a novel anisotropic supramolecular gel made of cyclodextrin-dye, in which physical gelation is completed by lithium salt. Rheological experiment reveals the elastic behaviors of the hydrogel, and high ionic conductivity represents a good mobility of ions inside the gel matrix.
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Affiliation(s)
- Jong S Park
- Laboratory of Polymer and Electronic Materials, Department of Nano Engineering & Textile Industry, Dong-A University, Busan 604-714, Korea.
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Jeon IY, Choi HJ, Bae SY, Chang DW, Baek JB. Wedging graphite into graphene and graphene-like platelets by dendritic macromolecules. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm10583c] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Chang DW, Jeon IY, Baek JB, Dai L. Efficient dispersion of singlewalled carbon nanotubes by novel amphiphilic dendrimers in water and substitution of the pre-adsorbed dendrimers with conventional surfactants and lipids. Chem Commun (Camb) 2010; 46:7924-6. [DOI: 10.1039/c0cc02833a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lee HJ, Chang DW, Park SM, Zakeeruddin SM, Grätzel M, Nazeeruddin MK. CdSe quantum dot (QD) and molecular dye hybrid sensitizers for TiO2 mesoporous solar cells: working together with a common hole carrier of cobalt complexes. Chem Commun (Camb) 2010; 46:8788-90. [DOI: 10.1039/c0cc03808c] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kim CH, Chang DW, Kim S, Park SY, Joo T. Excited state intramolecular proton transfer dynamics of semi-rigid polyquinoline in solution and polymer film. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2007.11.047] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Abstract
Carbon nanotubes (CNTs) have shown promise as an important new class of multifunctional building blocks and innovative tools in a large variety of applications, ranging from nanocomposite materials through nanoelectronics to biomedical devices. Because of their unusual one-dimensional hollow nanostructure and unique physicochemical properties, CNTs are particularly useful as novel drug delivery tools and imaging agents. However, such biomedical applications will not be realized if there is no proper assessment of the potential hazards of CNTs to humans and other biological systems. Although a few reports on the cytotoxicity of CNTs have been published, very little is known about the toxicity at the molecular level, or genotoxicity, of CNTs in mammalian cells. We have for the first time assessed the DNA damage response to multiwalled carbon nanotubes (MWNTs) in mouse embryonic stem (ES) cells. We found that MWNTs can accumulate and induce apoptosis in mouse ES cells and activate the tumor suppressor protein p53 within 2 h of exposure. Furthermore, we also observed increased expression of two isoforms of base excision repair protein 8-oxoguanine-DNA glycosylase 1 (OGG1), double strand break repair protein Rad 51, phosphorylation of H2AX histone at serine 139, and SUMO modification of XRCC4 following the treatment with MWNTs. A mutagenesis study using an endogenous molecular marker, adenine phosphoribosyltransferase (Aprt), showed that MWNTs increased the mutation frequency by 2-fold compared with the spontaneous mutation frequency in mouse ES cells. These results suggest that careful scrutiny of the genotoxicity of nanomaterials is needed even for those materials, like multiwalled carbon nanotubes, that have been previously demonstrated to have limited or no toxicity at the cellular level.
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Affiliation(s)
- Lin Zhu
- Department of Biology, Department of Chemical and Materials Engineering, University of Dayton, Dayton, OH 45469, USA
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Abstract
This case report describes the diagnosis of secondary malignant lymphoedema in two dogs that had undergone a mastectomy. A remarkable severe oedematous lesion associated with lameness in the right hindlimb was observed in both cases. Diagnostic imaging examinations, including direct pedal lymphangiography (case 1) and lymphoscintigraphy (case 2), showed obstruction of lymph flow in the lymphatics of the right hindlimbs. Although the recommended medical management and physiotherapy had been applied to resolve the problems, oedema did not improve in the damaged region in both cases. Results of histopathological examinations suggested that the cause of the obstructed lymph flow was neoplastic cells in the lymphatics of the right hindlimb in both dogs.
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Affiliation(s)
- J-H Kang
- Veterinary Medical Center, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea
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43
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Chang DW, Dai L. Luminescent amphiphilic dendrimers with oligo(p-phenylene vinylene) core branches and oligo(ethylene oxide) terminal chains: syntheses and stimuli-responsive properties. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b613278b] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kim S, Chang DW, Park SY, Jeoung SC, Kim D. Excited-State Intramolecular Proton Transfer and Stimulated Emission from Phototautomerizable Polyquinoline Film. Macromolecules 2002. [DOI: 10.1021/ma020319z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sehoon Kim
- School of Materials Science and Engineering, Seoul National University, ENG 445, San 56-1, Shillim-dong, Kwanak-ku, Seoul 151-744, Korea
| | - Dong Wook Chang
- School of Materials Science and Engineering, Seoul National University, ENG 445, San 56-1, Shillim-dong, Kwanak-ku, Seoul 151-744, Korea
| | - Soo Young Park
- School of Materials Science and Engineering, Seoul National University, ENG 445, San 56-1, Shillim-dong, Kwanak-ku, Seoul 151-744, Korea
| | - Sae Chae Jeoung
- Laser Metrology Group, Korea Research Institute of Standards and Science, Taejon 305-600, Korea
| | - Dongho Kim
- Center for Ultrafast Optical Characteristics Control and Department of Chemistry, Yonsei University, Seoul 120-749, Korea
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Kim S, Chang DW, Park SY, Kawai H, Nagamura T. Excited-State Intramolecular Proton Transfer in a Dendritic Macromolecular System: Poly(aryl ether) Dendrimers with Phototautomerizable Quinoline Core. Macromolecules 2002. [DOI: 10.1021/ma011385o] [Citation(s) in RCA: 28] [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: 11/28/2022]
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Abstract
BACKGROUND The purpose of this study was to assess the effectiveness of free tissue transfer for treatment of advanced mandibular osteoradionecrosis (ORN) in head and neck cancer patients. METHODS We reviewed 29 patients who were treated for advanced mandibular ORN by radical resection and reconstruction with free flaps at our institution. All patients had either failed to respond to conservative treatment, including hyperbaric oxygen therapy and debridement or had pathological fracture due to ORN. RESULTS Twenty-four vascularized bone (17 fibula, five iliac, and two scapula), four rectus abdominis myocutaneous, and one radial forearm fasciocutaneous free flaps were used. The complications occurred in 6 of 29 patients (21%). A total of four flaps (14%) were lost. The mean follow-up was 2 years 9 months. All patients had complete resolution of ORN symptoms. No evidence of ORN recurrence was observed in any patient. CONCLUSION For advanced osteoradionecrosis of the mandible, radical resection followed by reconstruction using free flap provides a reliable means of obtaining good wound healing with acceptable aesthetic and functional results.
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Affiliation(s)
- D W Chang
- Department of Plastic and Reconstructive Surgery, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Box 443, Houston, Texas 77030, USA.
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Affiliation(s)
- D W Chang
- Department of Plastic Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
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Chang DW, Kroll SS, Dackiw A, Singletary SE, Robb GL. Reconstructive management of contralateral breast cancer in patients who previously underwent unilateral breast reconstruction. Plast Reconstr Surg 2001; 108:352-8; discussion 359-60. [PMID: 11496174 DOI: 10.1097/00006534-200108000-00011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
When a patient who has had unilateral breast reconstruction presents with a new cancer on the opposite side, the reconstructive management of the second breast can be unclear. This study was performed to determine whether reconstruction of the second breast is oncologically reasonable and to evaluate the reconstructive options available to these patients. Patients who had mastectomy with unilateral breast reconstruction between 1988 and 1994 and who had a minimal follow-up of 5 years from the initial breast cancer were reviewed. Of 469 patients reviewed, 18 patients (4 percent) were identified who developed contralateral breast cancer. Mean age at the initial breast cancer presentation was 43 years (range, 26 to 57 years), and mean age at presentation with contralateral breast cancer was 48 years (range, 36 to 67). The mean interval between the initial and contralateral breast cancer presentations was 5 years (range, 1 to 10 years). Mean follow-up from the time of contralateral breast cancer was 5 years (range, 1 to 9 years). In most cases, contralateral breast cancer presented at an early stage (13 of 18 patients; 72 percent), and a shift to an earlier stage at presentation of the contralateral cancer was evident compared with the initial breast cancer. Of the 18 patients who developed contralateral breast cancer, 16 (89 percent) had no evidence of disease, one was alive with disease, and one died. Reconstructive management after the initial mastectomy included 16 transverse rectus abdominis myocutaneous flaps (seven free and nine pedicled), one latissimus dorsi myocutaneous flap with implant, and one superior gluteal free flap. Surgical management of the second breast after contralateral breast cancer included breast conservation in two patients, mastectomy without reconstruction in four, and mastectomy with reconstruction in 12. Reconstruction of the second breast included one free transverse rectus abdominis myocutaneous flap, three extended latissimus dorsi flaps, two latissimus dorsi myocutaneous flaps with implants, three implants alone, two Rubens flaps, and one superior gluteal free flap. No major complications were noted after the reconstruction of the second breast. The best symmetry was obtained when similar methods and tissues were used on both sides. The incidence of contralateral breast cancer after mastectomy and unilateral breast reconstruction is low. In most cases, contralateral breast cancer presents at an earlier stage compared with the initial breast cancer, and the prognosis is good. In patients who develop a contralateral breast cancer after mastectomy and unilateral breast reconstruction, the reconstruction of the second breast after mastectomy is oncologically reasonable and should be offered to provide optimal breast symmetry and a better quality of life. The best result is obtained when similar methods and tissues are used on both sides.
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Affiliation(s)
- D W Chang
- Department of Plastic Surgery and Surgical Oncology, The University of Texas M. D. Anderson Cancer Center Houston, TX 77030, USA.
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Abstract
The authors describe a case in which the dominant blood supply to a subperiosteally-harvested serratus anterior muscle and rib composite myoosseous free flap came from the lateral thoracic artery. There were no other associated features in this patient to warn of the vascular variant. Reconstructive surgeons should be aware of possible variations in the vascular anatomy of this flap.
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Affiliation(s)
- J E Lipa
- Department of Plastic Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030-4009, USA
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Tran NV, Chang DW, Gupta A, Kroll SS, Robb GL. Comparison of immediate and delayed free TRAM flap breast reconstruction in patients receiving postmastectomy radiation therapy. Plast Reconstr Surg 2001; 108:78-82. [PMID: 11420508 DOI: 10.1097/00006534-200107000-00013] [Citation(s) in RCA: 271] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Tumor pathologic features and the extent of nodal involvement dictate whether radiation therapy is given after mastectomy for breast cancer. It is generally well accepted that radiation negatively influences the outcome of implant-based breast reconstruction. However, the long-term effect of radiation therapy on the outcome of breast reconstruction with the free transverse rectus abdominis myocutaneous (TRAM) flap is still unclear. For patients who need postmastectomy radiation therapy, the optimal timing of TRAM flap reconstruction is controversial. This study compares the outcome of immediate and delayed free TRAM flap breast reconstruction in patients who received postmastectomy radiation therapy. All patients at The University of Texas M. D. Anderson Cancer Center who received postmastectomy radiation therapy and who also underwent free TRAM flap breast reconstruction between January of 1988 and December of 1998 were included in the study. Patients who received radiation therapy before delayed TRAM flap reconstruction were compared with patients who underwent immediate TRAM flap reconstruction before radiation therapy. Early and late complications were compared between the two groups. Early complications included vessel thrombosis, partial or total flap loss, mastectomy skin flap necrosis, and local wound-healing problems, whereas late complications included fat necrosis, volume loss, and flap contracture of free TRAM breast mounds. Late complications were evaluated at least 1 year after the completion of radiation therapy for patients who had delayed reconstruction and at least 1 year after reconstruction for patients who had immediate reconstruction. During the study period, 32 patients had immediate TRAM flap reconstruction before radiation therapy and 70 patients had radiation therapy before TRAM flap reconstruction. Mean follow-up times for the immediate reconstruction and delayed reconstruction groups were 3 and 5 years, respectively. The mean radiation dose was 50 Gy in the immediate reconstruction group and 51 Gy in the delayed reconstruction group. One complete flap loss occurred in the delayed reconstruction group, and no flap loss occurred in the immediate reconstruction group. The incidence of early complications did not differ significantly between the two groups. However, the incidence of late complications was significantly higher in the immediate reconstruction group than in the delayed reconstruction group (87.5 percent versus 8.6 percent; p = 0.000). Nine patients (28 percent) in the immediate reconstruction group required an additional flap to correct the distorted contour from flap shrinkage and severe flap contraction. These findings indicate that, in patients who are candidates for free TRAM flap breast reconstruction and need postmastectomy radiation therapy, reconstruction should be delayed until radiation therapy is complete.
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Affiliation(s)
- N V Tran
- Department of Plastic Surgery, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
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