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Title: Formation of environmentally persistent free radicals (EPFRs) on ZnO at room temperature: Implications for the fundamental model of EPFR generation

Authors:
; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1397620
Grant/Contract Number:
SC0012432
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Chemical Physics Letters
Additional Journal Information:
Journal Volume: 670; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-04 21:43:29; Journal ID: ISSN 0009-2614
Publisher:
Elsevier
Country of Publication:
Netherlands
Language:
English

Citation Formats

Patterson, Matthew C., DiTusa, Mark F., McFerrin, Cheri A., Kurtz, R. L., Hall, Randall W., Poliakoff, E. D., and Sprunger, P. T. Formation of environmentally persistent free radicals (EPFRs) on ZnO at room temperature: Implications for the fundamental model of EPFR generation. Netherlands: N. p., 2017. Web. doi:10.1016/j.cplett.2016.12.061.
Patterson, Matthew C., DiTusa, Mark F., McFerrin, Cheri A., Kurtz, R. L., Hall, Randall W., Poliakoff, E. D., & Sprunger, P. T. Formation of environmentally persistent free radicals (EPFRs) on ZnO at room temperature: Implications for the fundamental model of EPFR generation. Netherlands. doi:10.1016/j.cplett.2016.12.061.
Patterson, Matthew C., DiTusa, Mark F., McFerrin, Cheri A., Kurtz, R. L., Hall, Randall W., Poliakoff, E. D., and Sprunger, P. T. Wed . "Formation of environmentally persistent free radicals (EPFRs) on ZnO at room temperature: Implications for the fundamental model of EPFR generation". Netherlands. doi:10.1016/j.cplett.2016.12.061.
@article{osti_1397620,
title = {Formation of environmentally persistent free radicals (EPFRs) on ZnO at room temperature: Implications for the fundamental model of EPFR generation},
author = {Patterson, Matthew C. and DiTusa, Mark F. and McFerrin, Cheri A. and Kurtz, R. L. and Hall, Randall W. and Poliakoff, E. D. and Sprunger, P. T.},
abstractNote = {},
doi = {10.1016/j.cplett.2016.12.061},
journal = {Chemical Physics Letters},
number = C,
volume = 670,
place = {Netherlands},
year = {Wed Feb 01 00:00:00 EST 2017},
month = {Wed Feb 01 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.cplett.2016.12.061

Citation Metrics:
Cited by: 1work
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  • Combustion processes generate particulate matter that affects human health. When incineration fuels include components that are highly enriched in aromatic hydrocarbons (especially halogenated varieties) and redox-active metals, ultrafine particulate matter containing air-stable, environmentally persistent free radicals (EPFRs) is generated. The exposure to fine EPFRs (less than 2.5 μm in diameter) has been shown to negatively influence pulmonary and cardiovascular functions in living organisms. The goal of this study was to determine if these EPFRs have a direct effect on cytochrome P450 function. This was accomplished by direct addition of the EPFRs to rat liver microsomal preparations and measurement of severalmore » P450 activities using form-selective substrates. The EPFRs used in this study were formed by heating vapors from an organic compound (either monochlorophenol (MCP230) or 1,2-dichlorobenzene (DCB230)) and 5% copper oxide supported on silica (approximately 0.2 μm in diameter) to 230 °C under vacuum. Both types of EPFRs (but not silica, physisorbed silica, or silica impregnated with copper oxide) dramatically inhibited the activities of CYP1A, CYP2B, CYP2E1, CYP2D2 and CYP3A when incubated at concentrations less than 0.1 mg/ml with microsomes and NADPH. Interestingly, at the same concentrations, the EPFRs did not inhibit HO-1 activity or the reduction of cytochrome c by NADPH-cytochrome P450 reductase. CYP2D2-selective metabolism by rat liver microsomes was examined in more detail. The inhibition of CYP2D2-selective metabolism by both DCB230- and MCP230-EPFRs appeared to be largely noncompetitive and was attenuated in the presence of catalase suggesting that reactive oxygen species may be involved in the mechanism of inhibition. - Highlights: • Combustion of organic pollutants generates long-lived particulate radicals (EPFRs). • EPFRs inhibit metabolism by all cytochromes P450 tested in rat liver microsomes. • EPFR-mediated inhibition is related to spin content and is sensitive to catalase. • EPFR inhibition of CYP2D2 is noncompetitive with respect to substrate. • Exposure to EPFRs may impair the ability to eliminate xenobiotics.« less
  • We have detected free radicals in the gas-phase smoke resulting from the combustion of several household materials. Materials were pyrolyzed by rapid heating in a quartz ignition tube in a flowing air stream. The filtered smoke was bubbled into a dodecane solution of alpha-phenyl-N-t-butylnitrone (PBN), and the resulting nitroxide radicals were detected by electron spin resonance. Cellulosic materials (birch plywood, cellulose, 1R1 research cigarette tobacco, and yellow pine) and dried exterior paint produce about the same yield of trapped radicals. The smoke from polyethylene and rubber produce approximately 2-fold more radicals than the smoke from the cellulosic materials. Nylon smokemore » yields about 10-fold less radicals than the cellulosic materials. The smokes from polyvinyl chloride and polytetraflouroethylene do not produce detectable spin adducts of PBN by this method. Where radicals were trapped, oxygen-centered spin adducts predominated; lesser amounts of carbon-centered spin adducts and an oxidation product of PBN were observed. Different oxygen-centered radicals were detected from different materials, as judged from the variation observed in the hyperfine splitting constants of the principal spin adducts. When cellulose smoke is dissolved in solution, radicals continue to be produced for at least 20 min, suggesting the production of a metastable species in the gas phase that decomposes to form radicals in solution.« less
  • Room-temperature photoluminescence has been studied in n-type bulk ZnO crystals representing three different growth methods and having free-carrier concentrations (n) ranging from 10{sup 13} to 10{sup 18} cm{sup -3}. The near-band-edge emission has both free-exciton and free-exciton-phonon contributions, with the strength of the phonon coupling dependent on sample defect concentrations. Band-gap shrinkage effects are used to explain a decrease in emission energy for the higher n values. Band filling and band nonparabolicity are predicted to be important for n>10{sup 19} cm{sup -3}. At 300 K, in the absence of free carriers, the free-exciton energy is 3.312{+-}0.004 eV.
  • ZnO thick Stress relaxed films were deposited by reactive magnetron sputtering on 2”-wafer of SiO{sub 2}/Si at room temperature. The residual stress of ZnO films was measured by measuring the curvature of wafer using laser scanning method and found in the range of 0.18 x 10{sup 9} to 11.28 x 10{sup 9} dyne/cm{sup 2} with compressive in nature. Sputter pressure changes the deposition rates, which strongly affects the residual stress and surface morphologies of ZnO films. The crystalline wurtzite structure of ZnO films were confirmed by X-ray diffraction and a shift in (0002) diffraction peak of ZnO towards lower 2θmore » angle was observed with increasing the compressive stress in the films. The band gap of ZnO films shows a red shift from ∼3.275 eV to ∼3.23 eV as compressive stress is increased, unlike the stress for III-nitride materials. A relationship between stress and band gap of ZnO was derived and proposed. The stress-free growth of piezoelectric films is very important for functional devices applications.« less
  • Radio frequency Magnetron sputtering technique was employed to fabricate ZnO thin films on quartz substrate at room temperature. The effect of varying oxygen to argon (O{sub 2}/Ar) gas ratio on the structural and photoluminescence properties of the film is analyzed.X-ray diffraction (XRD) spectra reveals the formation of hexagonal wurtzite structured ZnO thin films with preferred orientation along (002) plane. Photoluminescence (PL) characterization reveals the preparation of highly crystalline films exhibiting intense Ultraviolet (UV) emission with negligible amount of defects as indicated by the absence of Deep Level Emission (DLE) in the PL spectra.