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Quah T, Delaney KT, Fredrickson GH. Assessment of the partial saddle point approximation in field-theoretic polymer simulations. J Chem Phys 2023; 159:164103. [PMID: 37873956 DOI: 10.1063/5.0173047] [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: 08/19/2023] [Accepted: 10/06/2023] [Indexed: 10/25/2023] Open
Abstract
Field-theoretic simulations are numerical treatments of polymer field theory models that go beyond the mean-field self-consistent field theory level and have successfully captured a range of mesoscopic phenomena. Inherent in molecularly-based field theories is a "sign problem" associated with complex-valued Hamiltonian functionals. One route to field-theoretic simulations utilizes the complex Langevin (CL) method to importance sample complex-valued field configurations to bypass the sign problem. Although CL is exact in principle, it can be difficult to stabilize in strongly fluctuating systems. An alternate approach for blends or block copolymers with two segment species is to make a "partial saddle point approximation" (PSPA) in which the stiff pressure-like field is constrained to its mean-field value, eliminating the sign problem in the remaining field theory, allowing for traditional (real) sampling methods. The consequences of the PSPA are relatively unknown, and direct comparisons between the two methods are limited. Here, we quantitatively compare thermodynamic observables, order-disorder transitions, and periodic domain sizes predicted by the two approaches for a weakly compressible model of AB diblock copolymers. Using Gaussian fluctuation analysis, we validate our simulation observations, finding that the PSPA incorrectly captures trends in fluctuation corrections to certain thermodynamic observables, microdomain spacing, and location of order-disorder transitions. For incompressible models with contact interactions, we find similar discrepancies between the predictions of CL and PSPA, but these can be minimized by regularization procedures such as Morse calibration. These findings mandate caution in applying the PSPA to broader classes of soft-matter models and systems.
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Affiliation(s)
- Timothy Quah
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA
| | - Kris T Delaney
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, USA
| | - Glenn H Fredrickson
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, USA
- Materials Department, University of California, Santa Barbara, California 93106, USA
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Albanese K, Blankenship JR, Quah T, Zhang A, Delaney KT, Fredrickson GH, Bates CM, Hawker CJ. Improved Elastic Recovery from ABC Triblock Terpolymers. ACS Polym Au 2023; 3:376-382. [PMID: 37841950 PMCID: PMC10571101 DOI: 10.1021/acspolymersau.3c00012] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 10/17/2023]
Abstract
The promise of ABC triblock terpolymers for improving the mechanical properties of thermoplastic elastomers is demonstrated by comparison with symmetric ABA/CBC analogs having similar molecular weights and volume fraction of B and A/C domains. The ABC architecture enhances elasticity (up to 98% recovery over 10 cycles) in part through essentially full chain bridging between discrete hard domains leading to the minimization of mechanically unproductive loops. In addition, the unique phase space of ABC triblocks also enables the fraction of hard-block domains to be higher (fhard ≈ 0.4) while maintaining elasticity, which is traditionally only possible with non-linear architectures or highly asymmetric ABA triblock copolymers. These advantages of ABC triblock terpolymers provide a tunable platform to create materials with practical applications while improving our fundamental understanding of chain conformation and structure-property relationships in block copolymers.
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Affiliation(s)
- Kaitlin
R. Albanese
- Department
of Chemistry & Biochemistry, University
of California, Santa Barbara, California 93106, United States
- Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
| | - Jacob R. Blankenship
- Department
of Chemistry & Biochemistry, University
of California, Santa Barbara, California 93106, United States
- Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
| | - Timothy Quah
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Amy Zhang
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Kris T. Delaney
- Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
| | - Glenn H. Fredrickson
- Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
- Materials
Department, University of California, Santa Barbara, California 93106, United States
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Christopher M. Bates
- Department
of Chemistry & Biochemistry, University
of California, Santa Barbara, California 93106, United States
- Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
- Materials
Department, University of California, Santa Barbara, California 93106, United States
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Craig J. Hawker
- Department
of Chemistry & Biochemistry, University
of California, Santa Barbara, California 93106, United States
- Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
- Materials
Department, University of California, Santa Barbara, California 93106, United States
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Chen D, Quah T, Delaney KT, Fredrickson GH. Investigation of the Self-Assembly Behavior of Statistical Bottlebrush Copolymers via Self-Consistent Field Theory Simulations. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01622] [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: 11/28/2022]
Affiliation(s)
- Duyu Chen
- Materials Research Laboratory, University of California, Santa Barbara, California93106, United States
| | - Timothy Quah
- Department of Chemical Engineering, University of California, Santa Barbara, California93106, United States
| | - Kris T. Delaney
- Materials Research Laboratory, University of California, Santa Barbara, California93106, United States
| | - Glenn H. Fredrickson
- Materials Research Laboratory, University of California, Santa Barbara, California93106, United States
- Department of Chemical Engineering, University of California, Santa Barbara, California93106, United States
- Materials Department, University of California, Santa Barbara, California 93106, United States
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Vigil DL, Quah T, Sun D, Delaney KT, Fredrickson GH. Self-Consistent Field Theory Predicts Universal Phase Behavior for Linear, Comb, and Bottlebrush Diblock Copolymers. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniel L. Vigil
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Timothy Quah
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Dan Sun
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Kris T. Delaney
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, United States
| | - Glenn H. Fredrickson
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, United States
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Owen CN, Bai X, Quah T, Lo SN, Allayous C, Callaghan S, Martínez-Vila C, Wallace R, Bhave P, Reijers ILM, Thompson N, Vanella V, Gerard CL, Aspeslagh S, Labianca A, Khattak A, Mandala M, Xu W, Neyns B, Michielin O, Blank CU, Welsh SJ, Haydon A, Sandhu S, Mangana J, McQuade JL, Ascierto PA, Zimmer L, Johnson DB, Arance A, Lorigan P, Lebbé C, Carlino MS, Sullivan RJ, Long GV, Menzies AM. Delayed immune-related adverse events with anti-PD-1-based immunotherapy in melanoma. Ann Oncol 2021; 32:917-925. [PMID: 33798657 DOI: 10.1016/j.annonc.2021.03.204] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 03/09/2021] [Accepted: 03/28/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Immune-related adverse events (irAEs) typically occur within 4 months of starting anti-programmed cell death protein 1 (PD-1)-based therapy [anti-PD-1 ± anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA4)], but delayed irAEs (onset >12 months after commencement) can also occur. This study describes the incidence, nature and management of delayed irAEs in patients receiving anti-PD-1-based immunotherapy. PATIENTS AND METHODS Patients with delayed irAEs from 20 centres were studied. The incidence of delayed irAEs was estimated as a proportion of melanoma patients treated with anti-PD-1-based therapy and surviving >1 year. Onset, clinical features, management and outcomes of irAEs were examined. RESULTS One hundred and eighteen patients developed a total of 140 delayed irAEs (20 after initial combination with anti-CTLA4), with an estimated incidence of 5.3% (95% confidence interval 4.0-6.9, 53/999 patients at sites with available data). The median onset of delayed irAE was 16 months (range 12-53 months). Eighty-seven patients (74%) were on anti-PD-1 at irAE onset, 15 patients (12%) were <3 months from the last dose and 16 patients (14%) were >3 months from the last dose of anti-PD-1. The most common delayed irAEs were colitis, rash and pneumonitis; 55 of all irAEs (39%) were ≥grade 3. Steroids were required in 80 patients (68%), as well as an additional immunosuppressive agent in 27 patients (23%). There were two irAE-related deaths: encephalitis with onset during anti-PD-1 and a multiple-organ irAE with onset 11 months after ceasing anti-PD-1. Early irAEs (<12 months) had also occurred in 69 patients (58%), affecting a different organ from the delayed irAE in 59 patients (86%). CONCLUSIONS Delayed irAEs occur in a small but relevant subset of patients. Delayed irAEs are often different from previous irAEs, may be high grade and can lead to death. They mostly occur in patients still receiving anti-PD-1. The risk of delayed irAE should be considered when deciding the duration of treatment in responding patients. However, patients who stop treatment may also rarely develop delayed irAE.
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Affiliation(s)
- C N Owen
- Melanoma Institute Australia, The University of Sydney, Sydney, Australia; Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - X Bai
- Massachusetts General Hospital, Boston, USA; Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Melanoma, Peking University Cancer Hospital & Institute, Beijing, China
| | - T Quah
- Westmead and Blacktown Hospitals, Sydney, Australia
| | - S N Lo
- Melanoma Institute Australia, The University of Sydney, Sydney, Australia
| | - C Allayous
- Dermatology Department, Université de Paris, AP-HP Saint-Louis Hospital, INSERM, Paris, France
| | - S Callaghan
- The Christie NHS Foundation Trust, Manchester, UK
| | | | - R Wallace
- Peter MacCallum Cancer Centre and the University of Melbourne, Melbourne, Australia
| | - P Bhave
- The Alfred Hospital, Melbourne, Australia
| | - I L M Reijers
- Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - N Thompson
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - V Vanella
- Istituto Nazionale Tumori IRCCS Fondazione Pascale, Napoli, Italy
| | - C L Gerard
- Lausanne University Hospital, Lausanne, Switzerland
| | - S Aspeslagh
- University Hospital Brussels, Brussels, Belgium
| | - A Labianca
- Papa Giovanni XXIII Cancer Center Hospital, Bergamo, Italy
| | - A Khattak
- Fiona Stanley Hospital and Edith Cowan University, Perth, Australia
| | - M Mandala
- University of Perugia, Unit of Medical Oncology, Santa Maria misericordia hospital, Perugia, Italy
| | - W Xu
- Princess Alexandra Hospital and The University of Queensland, Brisbane, Australia
| | - B Neyns
- University Hospital Brussels, Brussels, Belgium
| | - O Michielin
- Lausanne University Hospital, Lausanne, Switzerland
| | - C U Blank
- Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - S J Welsh
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - A Haydon
- The Alfred Hospital, Melbourne, Australia
| | - S Sandhu
- Peter MacCallum Cancer Centre and the University of Melbourne, Melbourne, Australia
| | - J Mangana
- Dermatology, Department of Dermato-Oncology, University Hospital Zurich, Zürich, Switzerland
| | - J L McQuade
- The University of Texas MD Anderson Cancer Center, Houston, USA
| | - P A Ascierto
- Istituto Nazionale Tumori IRCCS Fondazione Pascale, Napoli, Italy
| | - L Zimmer
- Department of Dermatology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - D B Johnson
- Vanderbilt University Medical Center, Nashville, USA
| | - A Arance
- Hospital Clinic Barcelona, Barcelona, Spain
| | - P Lorigan
- The Christie NHS Foundation Trust, Manchester, UK; The University of Manchester, Manchester, UK
| | - C Lebbé
- Dermatology Department, Université de Paris, AP-HP Saint-Louis Hospital, INSERM, Paris, France
| | - M S Carlino
- Melanoma Institute Australia, The University of Sydney, Sydney, Australia; Westmead and Blacktown Hospitals, Sydney, Australia
| | | | - G V Long
- Melanoma Institute Australia, The University of Sydney, Sydney, Australia; Royal North Shore Hospital, Sydney, Australia; Mater Hospital, Sydney, Australia.
| | - A M Menzies
- Melanoma Institute Australia, The University of Sydney, Sydney, Australia; Royal North Shore Hospital, Sydney, Australia; Mater Hospital, Sydney, Australia
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Sayahi T, Garff A, Quah T, Lê K, Becnel T, Powell KM, Gaillardon PE, Butterfield AE, Kelly KE. Long-term calibration models to estimate ozone concentrations with a metal oxide sensor. Environ Pollut 2020; 267:115363. [PMID: 32871483 DOI: 10.1016/j.envpol.2020.115363] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 08/02/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
Ozone (O3) is a potent oxidant associated with adverse health effects. Low-cost O3 sensors, such as metal oxide (MO) sensors, can complement regulatory O3 measurements and enhance the spatiotemporal resolution of measurements. However, the quality of MO sensor data remains a challenge. The University of Utah has a network of low-cost air quality sensors (called AirU) that primarily measures PM2.5 concentrations around the Salt Lake City valley (Utah, U.S.). The AirU package also contains a low-cost MO sensor ($8) that measures oxidizing/reducing species. These MO sensors exhibited excellent laboratory response to O3 although they exhibited some intra-sensor variability. Field performance was evaluated by placing eight AirUs at two Division of Air Quality (DAQ) monitoring stations with O3 federal equivalence methods for one year to develop long-term multiple linear regression (MLR) and artificial neural network (ANN) calibration models to predict O3 concentrations. Six sensors served as train/test sets. The remaining two sensors served as a holdout set to evaluate the applicability of the new calibration models in predicting O3 concentrations for other sensors of the same type. A rigorous variable selection method was also performed by least absolute shrinkage and selection operator (LASSO), MLR and ANN models. The variable selection indicated that the AirU's MO oxidizing species and temperature measurements and DAQ's solar radiation measurements were the most important variables. The MLR calibration model exhibited moderate performance (R2 = 0.491), and the ANN exhibited good performance (R2 = 0.767) for the holdout set. We also evaluated the performance of the MLR and ANN models in predicting O3 for five months after the calibration period and the results showed moderate correlations (R2s of 0.427 and 0.567, respectively). These low-cost MO sensors combined with a long-term ANN calibration model can complement reference measurements to understand geospatial and temporal differences in O3 levels.
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Affiliation(s)
- Tofigh Sayahi
- University of Utah, Department of Chemical Engineering, 3290 MEB, 50 S. Central Campus Dr., Salt Lake City, UT, United States.
| | - Alicia Garff
- University of Utah, Department of Physics and Astronomy, 201 James Fletcher Building, 115 S. 1400 E, Salt Lake City, UT, United States
| | - Timothy Quah
- University of California, Santa Barbara, Department of Chemical Engineering, 3357 Engrg II, Santa Barbara, CA, United States
| | - Katrina Lê
- University of Utah, Department of Chemical Engineering, 3290 MEB, 50 S. Central Campus Dr., Salt Lake City, UT, United States
| | - Thomas Becnel
- University of Utah, Department of Electrical and Computer Engineering, Laboratory for NanoIntegrated Systems, 50 S. Central Campus Dr., Salt Lake City, UT, United States
| | - Kody M Powell
- University of Utah, Department of Chemical Engineering, 3290 MEB, 50 S. Central Campus Dr., Salt Lake City, UT, United States
| | - Pierre-Emmanuel Gaillardon
- University of Utah, Department of Electrical and Computer Engineering, Laboratory for NanoIntegrated Systems, 50 S. Central Campus Dr., Salt Lake City, UT, United States
| | - Anthony E Butterfield
- University of Utah, Department of Chemical Engineering, 3290 MEB, 50 S. Central Campus Dr., Salt Lake City, UT, United States
| | - Kerry E Kelly
- University of Utah, Department of Chemical Engineering, 3290 MEB, 50 S. Central Campus Dr., Salt Lake City, UT, United States
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Owen C, Bai X, Quah T, Lo S, Callaghan S, Martínez-Vila C, Bhave P, Reijers I, Gerard C, Aspelagh S, Xu W, Welsh S, Sandhu S, Mangana J, McQuade J, Ascierto P, Zimmer L, Johnson D, Lebbé C, Menzies A. 1138P Delayed immune-related adverse events (irAEs) on anti-PD1-based therapy. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.08.1261] [Citation(s) in RCA: 2] [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: 11/29/2022] Open
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Abstract
Bottlebrush block polymers are a promising platform for self-assembled photonic materials, yet most work has been limited to one-dimensional photonic crystals based on the lamellar phase. Here we demonstrate with simulation that nonfrustrated ABC bottlebrush block polymers can be used to self-assemble three-dimensional photonic crystals with complete photonic band gaps. To show this, we have developed a computational approach that couples self-consistent field theory (SCFT) simulations to Maxwell's equations, thereby permitting a direct link between molecular design, self-assembly, and photonic band structures. Using this approach, we calculate the phase diagram of nonfrustrated ABC bottlebrush block polymers and identify regions where the alternating gyroid and alternating diamond phases are stable. By computing the photonic band structures of these phases, we demonstrate that complete band gaps can be found in regions of thermodynamic stability, thereby suggesting a route to realize these photonic materials experimentally. Furthermore, we demonstrate that gap size depends on volume fraction, segregation strength, and polymer architecture, and we identify a design strategy based on symmetry breaking that can achieve band gaps for lower values of refractive index contrast. Taken together, the approach presented here provides a powerful and flexible tool for predicting both the self-assembly and photonic band structures of polymeric materials.
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Affiliation(s)
- Joshua Lequieu
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
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Affiliation(s)
- Mengwei Yuan
- Department of Chemistry, University of Utah, 315 S 1400 E, Salt Lake City, Utah 84112, United States
| | - Matthew J. Kummer
- Department of Chemistry, University of Utah, 315 S 1400 E, Salt Lake City, Utah 84112, United States
| | - Ross D. Milton
- Department of Chemistry, University of Utah, 315 S 1400 E, Salt Lake City, Utah 84112, United States
| | - Timothy Quah
- Department of Chemistry, University of Utah, 315 S 1400 E, Salt Lake City, Utah 84112, United States
| | - Shelley D. Minteer
- Department of Chemistry, University of Utah, 315 S 1400 E, Salt Lake City, Utah 84112, United States
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Quah T, Milton RD, Abdellaoui S, Minteer SD. Bioelectrocatalytic NAD+/NADH inter-conversion: transformation of an enzymatic fuel cell into an enzymatic redox flow battery. Chem Commun (Camb) 2017; 53:8411-8414. [DOI: 10.1039/c7cc03842a] [Citation(s) in RCA: 22] [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] [Indexed: 11/21/2022]
Abstract
Diaphorase and a benzylpropylviologen redox polymer were combined to create a bioelectrode that can both oxidize NADH and reduce NAD+.
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Affiliation(s)
- Timothy Quah
- Department of Chemistry
- University of Utah
- Salt Lake City
- USA
| | - Ross D. Milton
- Department of Chemistry
- University of Utah
- Salt Lake City
- USA
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Abdellaoui S, Milton RD, Quah T, Minteer SD. NAD-dependent dehydrogenase bioelectrocatalysis: the ability of a naphthoquinone redox polymer to regenerate NAD. Chem Commun (Camb) 2016; 52:1147-50. [PMID: 26618758 DOI: 10.1039/c5cc09161f] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Electron mediation between NAD-dependent enzymes using quinone moieties typically requires the use of a diaphorase as an intermediary enzyme. The ability for a naphthoquinone redox polymer to independently oxidize enzymatically-generated NADH is demonstrated for application to glucose/O2 enzymatic fuel cells.
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Affiliation(s)
- Sofiene Abdellaoui
- Departments of Chemistry and Materials Science and Engineering, University of Utah, 315 S 1400 E, Room 2020, Salt Lake City, UT 84112, USA.
| | - Ross D Milton
- Departments of Chemistry and Materials Science and Engineering, University of Utah, 315 S 1400 E, Room 2020, Salt Lake City, UT 84112, USA.
| | - Timothy Quah
- Departments of Chemistry and Materials Science and Engineering, University of Utah, 315 S 1400 E, Room 2020, Salt Lake City, UT 84112, USA.
| | - Shelley D Minteer
- Departments of Chemistry and Materials Science and Engineering, University of Utah, 315 S 1400 E, Room 2020, Salt Lake City, UT 84112, USA.
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