1
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Roberts TD, Costa PB, Lynn SK, Coburn JW. Effects of Percussive Massage Treatments on Symptoms Associated with Eccentric Exercise-Induced Muscle Damage. J Sports Sci Med 2024; 23:126-135. [PMID: 38455428 PMCID: PMC10915620 DOI: 10.52082/jssm.2024.126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 01/11/2024] [Indexed: 03/09/2024]
Abstract
Percussive massage (PM) is an emerging recovery treatment despite the lack of research on its effects post-eccentric exercise (post-EE). This study investigated the effects of PM treatments (immediately, 24, 48, and 72 h post-EE) on the maximal isometric torque (MIT), range of motion (ROM), and an 11-point numerical rating scale (NRS) of soreness of the nondominant arm's biceps brachii from 24-72 h post-EE. Seventeen untrained, college-aged subjects performed 60 eccentric elbow flexion actions with their nondominant arms. Nine received 1 minute of PM, versus eight who rested quietly (control [CON]). In order, NRS, ROM, and MIT (relative to body mass) were collected pre-eccentric exercise (pre-EE) and after treatment (AT) at 24, 48, and 72 h post-EE. NRS was also collected before treatment (BT). Electromyographic (EMG) and mechanomyographic (MMG) amplitudes were collected during the MIT and normalized to pre-EE. There were no interactions for MIT, EMG, or MMG, but there were interactions for ROM and NRS. For ROM, the PM group had higher values than the CON 24-72 h by ~6-8°, a faster return to pre-EE (PM: 48 h, CON: 72 h), and exceeded their pre-EE at 72 h by ~4°. The groups' NRS values did not differ BT 24-72 h; however, the PM group lowered their NRS from BT to AT within every visit by ~1 point per visit, which resulted in them having lower values than the CON from 24-72 h by ~2-3 points. Additionally, the PM group returned their NRS to pre-EE faster than the CON (PM: BT 72 h, CON: never). In conclusion, PM treatments may improve ROM without affecting isometric strength or muscle activation 24-72 h post-EE. Although the PM treatments did not enhance the recovery from delayed onset muscle soreness until 72 h, they consistently provided immediate, temporary relief when used 24-72 h post-EE.
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Affiliation(s)
- Trevor D Roberts
- California State University, Fullerton; Center for Sport Performance and Exercise Physiology Lab; Fullerton, CA, USA
| | - Pablo B Costa
- California State University, Fullerton; Center for Sport Performance and Exercise Physiology Lab; Fullerton, CA, USA
| | - Scott K Lynn
- California State University, Fullerton; Center for Sport Performance and Exercise Physiology Lab; Fullerton, CA, USA
| | - Jared W Coburn
- California State University, Fullerton; Center for Sport Performance and Exercise Physiology Lab; Fullerton, CA, USA
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2
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Yuan R, Roberts TD, Brinn RM, Choi AA, Park HH, Yan C, Ondry JC, Khorasani S, Masiello DJ, Xu K, Alivisatos AP, Ginsberg NS. A composite electrodynamic mechanism to reconcile spatiotemporally resolved exciton transport in quantum dot superlattices. Sci Adv 2023; 9:eadh2410. [PMID: 37862422 PMCID: PMC10588942 DOI: 10.1126/sciadv.adh2410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 09/20/2023] [Indexed: 10/22/2023]
Abstract
Quantum dot (QD) solids are promising optoelectronic materials; further advancing their device functionality requires understanding their energy transport mechanisms. The commonly invoked near-field Förster resonance energy transfer (FRET) theory often underestimates the exciton hopping rate in QD solids, yet no consensus exists on the underlying cause. In response, we use time-resolved ultrafast stimulated emission depletion (STED) microscopy, an ultrafast transformation of STED to spatiotemporally resolve exciton diffusion in tellurium-doped cadmium selenide-core/cadmium sulfide-shell QD superlattices. We measure the concomitant time-resolved exciton energy decay due to excitons sampling a heterogeneous energetic landscape within the superlattice. The heterogeneity is quantified by single-particle emission spectroscopy. This powerful multimodal set of observables provides sufficient constraints on a kinetic Monte Carlo simulation of exciton transport to elucidate a composite transport mechanism that includes both near-field FRET and previously neglected far-field emission/reabsorption contributions. Uncovering this mechanism offers a much-needed unified framework in which to characterize transport in QD solids and additional principles for device design.
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Affiliation(s)
- Rongfeng Yuan
- Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Trevor D. Roberts
- Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Rafaela M. Brinn
- Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Alexander A. Choi
- Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Ha H. Park
- Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Chang Yan
- Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Justin C. Ondry
- Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Siamak Khorasani
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA
| | - David J. Masiello
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Ke Xu
- Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
- STROBE, National Science Foundation Science and Technology Center, University of California Berkeley, Berkeley, CA 94720, USA
| | - A. Paul Alivisatos
- Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Naomi S. Ginsberg
- Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
- STROBE, National Science Foundation Science and Technology Center, University of California Berkeley, Berkeley, CA 94720, USA
- Department of Physics, University of California Berkeley, Berkeley, CA 94720, USA
- Materials Science Division and Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Kavli Energy NanoSciences Institute at Berkeley, Berkeley, CA 94720, USA
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3
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Bischoff AJ, Hamerlynck LM, Li AJ, Roberts TD, Ginsberg NS, Francis MB. Protein-Based Model for Energy Transfer between Photosynthetic Light-Harvesting Complexes Is Constructed Using a Direct Protein-Protein Conjugation Strategy. J Am Chem Soc 2023. [PMID: 37438911 PMCID: PMC10375525 DOI: 10.1021/jacs.3c02577] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Photosynthetic organisms utilize dynamic and complex networks of pigments bound within light-harvesting complexes to transfer solar energy from antenna complexes to reaction centers. Understanding the principles underlying the efficiency of these energy transfer processes, and how they may be incorporated into artificial light-harvesting systems, is facilitated by the construction of easily tunable model systems. We describe a protein-based model to mimic directional energy transfer between light-harvesting complexes using a circular permutant of the tobacco mosaic virus coat protein (cpTMV), which self-assembles into a 34-monomer hollow disk. Two populations of cpTMV assemblies, one labeled with donor chromophores and another labeled with acceptor chromophores, were coupled using a direct protein-protein bioconjugation method. Using potassium ferricyanide as an oxidant, assemblies containing o-aminotyrosine were activated toward the addition of assemblies containing p-aminophenylalanine. Both of these noncanonical amino acids were introduced into the cpTMV monomers through amber codon suppression. This coupling strategy has the advantages of directly, irreversibly, and site-selectively coupling donor with acceptor protein assemblies and avoids cross-reactivity with native amino acids and undesired donor-donor or acceptor-acceptor combinations. The coupled donor-acceptor model was shown to transfer energy from an antenna disk containing donor chromophores to a downstream disk containing acceptor chromophores. This model ultimately provides a controllable and modifiable platform for understanding photosynthetic interassembly energy transfer and may lead to the design of more efficient functional light-harvesting materials.
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Affiliation(s)
- Amanda J Bischoff
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Leo M Hamerlynck
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Amanda J Li
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Trevor D Roberts
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Naomi S Ginsberg
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Physics, University of California, Berkeley, California 94720, United States
- Kavli Energy NanoScience Institute, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Matthew B Francis
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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4
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Hamerlynck LM, Bischoff AJ, Rogers JR, Roberts TD, Dai J, Geissler PL, Francis MB, Ginsberg NS. Static Disorder has Dynamic Impact on Energy Transport in Biomimetic Light-Harvesting Complexes. J Phys Chem B 2022; 126:7981-7991. [PMID: 36191182 PMCID: PMC9574921 DOI: 10.1021/acs.jpcb.2c06614] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Despite extensive studies, many questions remain about
what structural
and energetic factors give rise to the remarkable energy transport
efficiency of photosynthetic light-harvesting protein complexes, owing
largely to the inability to synthetically control such factors in
these natural systems. Herein, we demonstrate energy transfer within
a biomimetic light-harvesting complex consisting of identical chromophores
attached in a circular array to a protein scaffold derived from the
tobacco mosaic virus coat protein. We confirm the capability of energy
transport by observing ultrafast depolarization in transient absorption
anisotropy measurements and a redshift in time-resolved emission spectra
in these complexes. Modeling the system with kinetic Monte Carlo simulations
recapitulates the observed anisotropy decays, suggesting an inter-site
hopping rate as high as 1.6 ps–1. With these simulations,
we identify static disorder in orientation, site energy, and degree
of coupling as key remaining factors to control to achieve long-range
energy transfer in these systems. We thereby establish this system
as a highly promising, bottom-up model for studying long-range energy
transfer in light-harvesting protein complexes.
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Affiliation(s)
- Leo M Hamerlynck
- Department of Chemistry, University of California Berkeley, Berkeley, California94720, United States.,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Amanda J Bischoff
- Department of Chemistry, University of California Berkeley, Berkeley, California94720, United States.,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Julia R Rogers
- Department of Chemistry, University of California Berkeley, Berkeley, California94720, United States
| | - Trevor D Roberts
- Department of Chemistry, University of California Berkeley, Berkeley, California94720, United States
| | - Jing Dai
- Department of Chemistry, University of California Berkeley, Berkeley, California94720, United States
| | - Phillip L Geissler
- Department of Chemistry, University of California Berkeley, Berkeley, California94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Matthew B Francis
- Department of Chemistry, University of California Berkeley, Berkeley, California94720, United States.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States.,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Naomi S Ginsberg
- Department of Chemistry, University of California Berkeley, Berkeley, California94720, United States.,Department of Physics, University of California Berkeley, Berkeley, California94720, United States.,Kavli Energy NanoSciences Institute, Berkeley, California94720, United States.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States.,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
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5
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Roberts TD, Yuan R, Xiang L, Delor M, Pokhrel R, Yang K, Aqad E, Marangoni T, Trefonas P, Xu K, Ginsberg NS. Direct Correlation of Single-Particle Motion to Amorphous Microstructural Components of Semicrystalline Poly(ethylene oxide) Electrolytic Films. J Phys Chem Lett 2020; 11:4849-4858. [PMID: 32510954 DOI: 10.1021/acs.jpclett.0c01318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Semicrystalline polymers constitute some of the most widely used materials in the world, and their functional properties are intimately connected to their structure on a range of length scales. Many of these properties depend on the micro- and nanoscale heterogeneous distribution of crystalline and amorphous phases, but this renders the interpretation of ensemble averaged measurements challenging. We use superlocalized widefield single-particle tracking in conjunction with AFM phase imaging to correlate the crystalline morphology of lithium-triflate-doped poly(ethylene oxide) thin films to the motion of individual fluorescent probes at the nanoscale. The results demonstrate that probe motion is intrinsically isotropic in amorphous regions and that, without altering this intrinsic diffusivity, closely spaced, often parallel, crystallite fibers anisotropically constrain probe motion along intercalating amorphous channels. This constraint is emphasized by the agreement between crystallite and anisotropic probe trajectory orientations. This constraint is also emphasized by the extent of the trajectory confinement correlated to the width of the measured gaps between adjacent crystallites. This study illustrates with direct nanoscale correlations how controlled and periodic arrangement of crystalline domains is a promising design principle for mass transport in semicrystalline polymer materials without compromising their mechanical stability.
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Affiliation(s)
- Trevor D Roberts
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
| | - Rongfeng Yuan
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
| | - Limin Xiang
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
| | - Milan Delor
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
| | - Ravi Pokhrel
- DuPont Electronics and Imaging, Marlborough, Massachusetts 01752, United States
| | - Ke Yang
- DuPont Electronics and Imaging, Marlborough, Massachusetts 01752, United States
| | - Emad Aqad
- DuPont Electronics and Imaging, Marlborough, Massachusetts 01752, United States
| | - Tomas Marangoni
- DuPont Electronics and Imaging, Marlborough, Massachusetts 01752, United States
| | - Peter Trefonas
- DuPont Electronics and Imaging, Marlborough, Massachusetts 01752, United States
| | - Ke Xu
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
- STROBE, National Science Foundation Science and Technology Center, University of California Berkeley, Berkeley, California 94720, United States
| | - Naomi S Ginsberg
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
- STROBE, National Science Foundation Science and Technology Center, University of California Berkeley, Berkeley, California 94720, United States
- Department of Physics, University of California Berkeley, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720, United States
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6
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Stern HL, Wang R, Fan Y, Mizuta R, Stewart JC, Needham LM, Roberts TD, Wai R, Ginsberg NS, Klenerman D, Hofmann S, Lee SF. Spectrally Resolved Photodynamics of Individual Emitters in Large-Area Monolayers of Hexagonal Boron Nitride. ACS Nano 2019; 13:4538-4547. [PMID: 30865421 DOI: 10.1021/acsnano.9b00274] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hexagonal boron nitride (h-BN) is a 2D, wide band gap semiconductor that has recently been shown to display bright room-temperature emission in the visible region, sparking immense interest in the material for use in quantum applications. In this work, we study highly crystalline, single atomic layers of chemical vapor deposition grown h-BN and find predominantly one type of emissive state. Using a multidimensional super-resolution fluorescence microscopy technique we simultaneously measure spatial position, intensity, and spectral properties of the emitters, as they are exposed to continuous wave illumination over minutes. As well as low emitter heterogeneity, we observe inhomogeneous broadening of emitter line-widths and power law dependency in fluorescence intermittency; this is strikingly similar to previous work on quantum dots. These results show that high control over h-BN growth and treatment can produce a narrow distribution of emitter type and that surface interactions heavily influence the photodynamics. Furthermore, we highlight the utility of spectrally resolved wide-field microscopy in the study of optically active excitations in atomically thin two-dimensional materials.
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Affiliation(s)
- Hannah L Stern
- Department of Chemistry , University of Cambridge , Lensfield Road , CB2 1EW , Cambridge , United Kingdom
| | - Ruizhi Wang
- Department of Engineering , University of Cambridge , JJ Thompson Avenue , CB3 0FA , Cambridge , United Kingdom
| | - Ye Fan
- Department of Engineering , University of Cambridge , JJ Thompson Avenue , CB3 0FA , Cambridge , United Kingdom
| | - Ryo Mizuta
- Department of Engineering , University of Cambridge , JJ Thompson Avenue , CB3 0FA , Cambridge , United Kingdom
| | - James C Stewart
- Department of Engineering , University of Cambridge , JJ Thompson Avenue , CB3 0FA , Cambridge , United Kingdom
| | - Lisa-Maria Needham
- Department of Chemistry , University of Cambridge , Lensfield Road , CB2 1EW , Cambridge , United Kingdom
| | - Trevor D Roberts
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Rebecca Wai
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Naomi S Ginsberg
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
- Department of Physics and Department of Chemistry , University of California , Berkeley , California 94720 , United States
- Molecular Biophysics and Integrated Bioimaging Division and Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Kavli Energy NanoSciences Institute , Berkeley , California 94720 , United States
| | - David Klenerman
- Department of Chemistry , University of Cambridge , Lensfield Road , CB2 1EW , Cambridge , United Kingdom
| | - Stephan Hofmann
- Department of Engineering , University of Cambridge , JJ Thompson Avenue , CB3 0FA , Cambridge , United Kingdom
| | - Steven F Lee
- Department of Chemistry , University of Cambridge , Lensfield Road , CB2 1EW , Cambridge , United Kingdom
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7
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Delor M, Dai J, Roberts TD, Rogers JR, Hamed SM, Neaton JB, Geissler PL, Francis MB, Ginsberg NS. Exploiting Chromophore–Protein Interactions through Linker Engineering To Tune Photoinduced Dynamics in a Biomimetic Light-Harvesting Platform. J Am Chem Soc 2018; 140:6278-6287. [DOI: 10.1021/jacs.7b13598] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | | | | | - Jeffrey B. Neaton
- Kavli Energy NanoSciences Institute, Berkeley, California 94720, United States
| | | | | | - Naomi S. Ginsberg
- Kavli Energy NanoSciences Institute, Berkeley, California 94720, United States
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8
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Delor M, McCarthy DG, Cotts BL, Roberts TD, Noriega R, Devore DD, Mukhopadhyay S, De Vries TS, Ginsberg NS. Resolving and Controlling Photoinduced Ultrafast Solvation in the Solid State. J Phys Chem Lett 2017; 8:4183-4190. [PMID: 28829138 DOI: 10.1021/acs.jpclett.7b01689] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Solid-state solvation (SSS) is a solid-state analogue of solvent-solute interactions in the liquid state. Although it could enable exceptionally fine control over the energetic properties of solid-state devices, its molecular mechanisms have remained largely unexplored. We use ultrafast transient absorption and optical Kerr effect spectroscopies to independently track and correlate both the excited-state dynamics of an organic emitter and the polarization anisotropy relaxation of a small polar dopant embedded in an amorphous polystyrene matrix. The results demonstrate that the dopants are able to rotationally reorient on ultrafast time scales following light-induced changes in the electronic configuration of the emitter, minimizing the system energy. The solid-state dopant-emitter dynamics are intrinsically analogous to liquid-state solvent-solute interactions. In addition, tuning the dopant/polymer pore ratio offers control over solvation dynamics by exploiting molecular-scale confinement of the dopants by the polymer matrix. Our findings will enable refined strategies for tuning optoelectronic material properties using SSS and offer new strategies to investigate mobility and disorder in heterogeneous solid and glassy materials.
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Affiliation(s)
| | | | | | | | | | - David D Devore
- The Dow Chemical Company , Midland, Michigan 48674, United States
| | | | | | - Naomi S Ginsberg
- Kavli Energy NanoSciences Institute , Berkeley, California 94720, United States
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9
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Scrape PG, Roberts TD, Lee SH, Butler LJ. Dissociation Pathways of the CH2CH2ONO Radical: NO2 + Ethene, NO + Oxirane, and a Non-Intrinsic Reaction Coordinate HNO + Vinoxy Pathway. J Phys Chem A 2016; 120:4973-87. [PMID: 27124098 DOI: 10.1021/acs.jpca.5b12669] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We first characterize the dissociation pathways of BrCH2CH2ONO, a substituted alkyl nitrite, upon photoexcitation at 193 nm under collision-free conditions, in a crossed laser-molecular beam scattering apparatus using vacuum ultraviolet photoionization detection. Three primary photodissociation pathways occur: photoelimination of HNO, leading to the products HNO + BrCH2CHO; C-Br bond photofission, leading to Br + CH2CH2ONO; and O-NO bond photofission, leading to NO + BrCH2CH2O. The data show that alkyl nitrites can eliminate HNO via a unimolecular mechanism in addition to the commonly accepted bulk disproportionation mechanism. Some of the products from the primary photodissociation pathways are highly vibrationally excited, so we then probe the product branching from the unimolecular dissociation of these unstable intermediates. Notably, the vibrationally excited CH2CH2ONO radicals undergo two channels predicted by statistical transition-state theory, and an additional non-intrinsic reaction coordinate channel, HNO elimination. CH2CH2ONO is formed with high rotational energy; by employing rotational models based on conservation of angular momentum, we predict, and verify experimentally, the kinetic energies of stable CH2CH2ONO radicals and the angular distribution of dissociation products. The major dissociation pathway of CH2CH2ONO is NO2 + ethene, and some of the NO2 is formed with sufficient internal energy to undergo further photodissociation. Nascent BrCH2CHO and CH2Br are also photodissociated upon absorption of a second 193 nm photon; we derive the kinetic energy release of these dissociations based on our data, noting similarities to the analogous photodissociation of ClCH2CHO and CH2Cl.
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Affiliation(s)
- Preston G Scrape
- The James Franck Institute and Department of Chemistry, The University of Chicago , Chicago, Illinois 60637, United States
| | - Trevor D Roberts
- The James Franck Institute and Department of Chemistry, The University of Chicago , Chicago, Illinois 60637, United States
| | - Shih-Huang Lee
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan, Republic of China
| | - Laurie J Butler
- The James Franck Institute and Department of Chemistry, The University of Chicago , Chicago, Illinois 60637, United States
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10
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Wang L, Scrape PG, Roberts TD, Joshi PP, Butler LJ. Competing C–Br and O–NO Photofission upon Excitation of BrCH2CH2ONO at 193 nm. J Phys Chem A 2015; 119:12005-14. [DOI: 10.1021/acs.jpca.5b04162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [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)
- Lei Wang
- The James
Franck Institute
and Department of Chemistry, The University of Chicago, Chicago, Illinois 60637 United States
| | - Preston G. Scrape
- The James
Franck Institute
and Department of Chemistry, The University of Chicago, Chicago, Illinois 60637 United States
| | - Trevor D. Roberts
- The James
Franck Institute
and Department of Chemistry, The University of Chicago, Chicago, Illinois 60637 United States
| | - Prakriti P. Joshi
- The James
Franck Institute
and Department of Chemistry, The University of Chicago, Chicago, Illinois 60637 United States
| | - Laurie J. Butler
- The James
Franck Institute
and Department of Chemistry, The University of Chicago, Chicago, Illinois 60637 United States
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11
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Abstract
Rhinocerebral mucormycosis is a rare angioinvasive fungal infection that has a strong predilection for patients with poorly controlled diabetes and immunosuppression. Initial presenting symptoms are nonspecific and frequently are attributed to more mundane sinonasal and orbital pathologies. Early diagnosis and treatment are essential for survival and minimizing neurologic sequelae. CT and MR imaging are often used in the diagnostic work-up; however, CT findings are nonspecific.
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Affiliation(s)
- S Safder
- Department of Radiology, West Virginia University Hospital, Morgantown, USA.
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12
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Oommen BJ, Roberts TD. Discretized learning automata solutions to the capacity assignment problem for prioritized networks. IEEE Trans Syst Man Cybern B Cybern 2008; 32:821-31. [PMID: 18244888 DOI: 10.1109/tsmcb.2002.1049616] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We present a discretized learning automaton (LA) solution to the capacity assignment (CA) problem which focuses on finding the best possible set of capacities for the links that satisfy the traffic requirements in a prioritized network while minimizing the cost. Most approaches consider a single class of packets flowing through the network, but in reality, different classes of packets with different average packet lengths and different priorities are transmitted over the networks. This generalized model is the focus of this paper. Although the problem is inherently NP-hard, a few approximate solutions have been proposed in the literature. Marayuma and Tang (1977) proposed a single algorithm composed of several elementary heuristic procedures. Other solutions tackle the problem by using modern-day artificial intelligence (AI) paradigms such as simulated annealing and genetic algorithms (GAs). In 2000, we introduced a new method, superior to these, that uses continuous LA. In this paper, we present a discretized LA solution to the problem. This solution uses a meta-action philosophy new to the field of LA, and is probably the best available solution to this extremely complex problem.
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Affiliation(s)
- B J Oommen
- Sch. of Comput. Sci., Carleton Univ., Ottawa, Ont., Canada
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13
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Chestnut DA, Popov SV, Taylor JR, Roberts TD. Red picosecond pulses generated by frequency doubling a Raman amplified widely tunable 1.3 microm fiber ring laser. Opt Lett 2005; 30:2769-71. [PMID: 16252769 DOI: 10.1364/ol.30.002769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We generated 0.66 microm picosecond pulses by second-harmonic generation of the Raman amplified output of a 1.3 microm actively mode-locked fiber ring laser in a periodically poled potassium titanyl phosphate (PPKTP) waveguide. The ring laser produced 9 ps pulses at a 20 GHz repetition frequency, was tunable over 1284-1330 nm, and was based on a semiconductor optical amplifier and a Mach-Zehnder amplitude modulator. The Raman amplifier served both to amplify the ring laser and to compress the pulses as solitons. The spectral flexibility of the amplifiers and the modulator should enable similar configurations to be made at other wavelengths and facilitate efficient frequency doubling in waveguides to other visible wavelengths.
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Affiliation(s)
- D A Chestnut
- Femtosecond Optics Group, Department of Physics, Imperial College, London, UK.
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Kokorowski DA, Cronin AD, Roberts TD, Pritchard DE. From single- to multiple-pPhoton decoherence in an atom interferometer. Phys Rev Lett 2001; 86:2191-2195. [PMID: 11289887 DOI: 10.1103/physrevlett.86.2191] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2000] [Indexed: 05/23/2023]
Abstract
We measure the decoherence of a spatially separated atomic superposition due to spontaneous photon scattering. We observe a qualitative change in decoherence versus separation as the number of scattered photons increases, and verify quantitatively the decoherence rate constant in the many-photon limit. Our results illustrate an evolution of decoherence consistent with general models developed for a broad class of decoherence phenomena.
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Affiliation(s)
- D A Kokorowski
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Roberts TD, Stenhouse G. Moving vector display for the study of balance and of the reactions to perturbation [proceedings]. J Physiol 1977; 273:8P-9P. [PMID: 599478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Abstract
1. Tonic labyrinth and neck reflexes were studied separately and in combination in the decerebrate cat with C1 and C2 spinal roots cut. Reflex effects were observed as changes in length of the isotonically loaded medial head of triceps. 2. The tonic labyrinth reflexes acted asymmetrically on the medial head of triceps. Side-down rotation of the head produced shortening in medial triceps, whereas side-up rotations of the head resulted in a lengthening. 3. The tonic neck reflexes acted asymmetrically on the medial head of triceps. Side-down rotations of the neck produced a lengthening of medial triceps, whereas side-up rotations of the neck resulted in shortening. 4. Labyrinth and neck reflexes produce opposite effects on the same limb extensor muscle so that, if the neck innervation is intact, head tilting produces no change in muscle length. 5. It is suggested that the interaction between the labyrinth and neck reflexes contributes to the stability of the trunk, allowing the head to move freely on the body without affecting this stability. Labyrinth and neck reflexes need therefore to be considered together as a single system.
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Abstract
On the ground the vertical directions "up" and "down" have significance in relation to the strategy for avoiding collision of the skull with the planet. Voluntary acts to this end may be based on the experienced result of reflexly generated motor commands. Relevant receptors lie in the otolith organs of the labyrinth, but the head is seldom steady in waking life. A revised scheme of labyrinth reflexes on the limbs--"downhill limbs extend"--replaces the classical scheme of Magnus. Interactions with neck reflexes according to this scheme serve to stabilize the trunk. In an orbiting spacecraft the pattern of afferent signals from the labyrinth differs from that on the ground, and predictions based on the new scheme are to be tested in the project "Operation Push-Pull" proposed for ESRO's Spacelab. Other activities of the Council of Europe's Working Party on Aerospace Physiology and Medicine are briefly described.
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Affiliation(s)
- T D Roberts
- Institute of Physiology, University of Glasgow, Glasgow, Scotland
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Roberts TD. Proceedings: Reflexes of balance (film). J Physiol 1974; 242:46P-47P. [PMID: 4455828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Roberts TD. Operation push-pull. An experiment to verify predictions about the interaction between neck reflexes and labyrinth reflexes in man. Agressologie 1973; 14:87-9. [PMID: 4793856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Roberts TD. Inversion illusion in the so-called zero-gravity conditions of parabolic flight. Aerosp Med 1973; 44:484-7. [PMID: 4710520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Roberts TD. Class experiment on reflex inhibition of the electrically recorded ankle jerk reflex in man. J Physiol 1970; 211:Suppl:7P-8P. [PMID: 5501045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Roberts TD. The role of knee joint kinematics in standing with a bent knee. J Physiol 1970; 211:Suppl:8P-9P. [PMID: 5501046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Roberts TD. Changes in stretch reflexes in limb extensor muscles during position reflexes from the labyrinth in the cat. J Physiol 1970; 211:Suppl:5P-6P. [PMID: 5501044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Roberts TD. A model to illustrate the effects of factors influencing the heart's action. J Physiol 1970; 211:Suppl:6P-7P. [PMID: 5505230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Roberts TD. Temperature control in fever. Confrontation of physiological theory with personal experience. Lancet 1970; 2:1015-8. [PMID: 4098047 DOI: 10.1016/s0140-6736(70)92819-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Roberts TD. The mechanics of the upright posture. Physiotherapy 1969; 55:398-404. [PMID: 5381288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Roberts TD. Static and dynamic components in the responses of muscle spindles to stretch, and their role in muscle control. Electroencephalogr Clin Neurophysiol 1968; 25:406. [PMID: 4176595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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