Biochemistry, Biophysics, and Structural Biology | Open Access Articles

Global Fire Emissions Estimates During 1997-2016, Guido R. Van Der Werf, James T. Randerson, Louis Giglio, Thijs T. Van Leeuwen, Yang Chen, Brendan M. Rogers, Mingquan Mu, Margreet J.E. Van Marle, Douglas C. Morton, G. James Collatz, Robert J. Yokelson, Prasad S. Kasibhatla

Chemistry and Biochemistry Faculty Publications

Climate, land use, and other anthropogenic and natural drivers have the potential to influence fire dynamics in many regions. To develop a mechanistic understanding of the changing role of these drivers and their impact on atmospheric composition, long-term fire records are needed that fuse information from different satellite and in situ data streams. Here we describe the fourth version of the Global Fire Emissions Database (GFED) and quantify global fire emissions patterns during 1997-2016. The modeling system, based on the Carnegie-Ames-Stanford Approach (CASA) biogeochemical model, has several modifications from the previous version and uses higher quality input datasets. Significant upgrades …

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Special Issue: Intramolecular Hydrogen Bonding 2017, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Even after more than a century of study [1–6], scrutiny, and detailed examination, the H-bond continues [7–12] to evoke a level of fascination that surpasses many other phenomena. Perhaps it is the ability of the simple H atom, with but a single electron, to act as a glue that maintains contact between much more complicated species. Or it might be its geometry, which prefers to hold the bridging proton on a direct line between the two heavy atoms. Not to be ignored are the spectral features of the H-bond: the large red shift of the stretching frequency of the covalent …

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A Bipyridine-Ligated Zinc(Ii) Complex With Bridging Flavonolate Ligation: Synthesis, Characterization, And Visible-Light-Induced Co Release Reactivity, Shayne Sorenson, Marina Popova, Atta M. Arif, Lisa M. Berreau

Chemistry and Biochemistry Faculty Publications

Metal-flavonolate compounds are of significant current interest as synthetic models for quercetinase enzymes and as bioactive compounds of importance to human health. Zinc-3-hydroxyflavonolate compounds, including those of quercetin, kampferol, and morin, generally exhibit bidentate coordination to a single ZnII center. The bipyridine-ligated zinc-flavonolate compound reported herein, namely bis(μ-4-oxo-2-phenyl-4H-chromen-3-olato)-κ3O3:O3,O4;κ3O3,O4:O3-bis[(2,2′-bipyridine-κ2N,N′)zinc(II)] bis(perchlorate), {[Zn2(C15H9O3)2(C10H8N2)2](ClO4)2}n, (1), provides an unusual example of bridging 3-hydroxyflavonolate ligation in a dinuclear metal complex. The symmetry-related ZnII centers of (1) exhibit a distorted octahedral geometry, with weak coordination of a perchlorate anion trans to the bridging deprotonated O atom of the flavonolate ligand. Variable-concentration conductivity measurements provide evidence that, when …

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Unraveling The Interactions Of The Physiological Reductant Flavodoxin With The Different Conformations Of The Fe Protein In The Nitrogenase Cycle, Natasha Pence, Monika Tokmina-Lukaszewska, Zhi-Yong Yang, Rhesa N. Ledbetter, Lance C. Seefeldt, Brian Bothner, John W. Peters

Chemistry and Biochemistry Faculty Publications

Nitrogenase reduces dinitrogen (N2) to ammonia in biological nitrogen fixation. The nitrogenase Fe protein cycle involves a transient association between the reduced, MgATP-bound Fe protein and the MoFe protein and includes electron transfer, ATP hydrolysis, release of Pi, and dissociation of the oxidized, MgADP-bound Fe protein from the MoFe protein. The cycle is completed by reduction of oxidized Fe protein and nucleotide exchange. Recently, a kinetic study of the nitrogenase Fe protein cycle involving the physiological reductant flavodoxin reported a major revision of the rate-limiting step from MoFe protein and Fe protein dissociation to release of Pi. Because the Fe …

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Relative Importance Of Black Carbon, Brown Carbon, And Absorption Enhancement From Clear Coatings In Biomass Burning Emissions, Rudra P. Pokhrel, Eric R. Beamesderfer, Nick L. Wagner, Justin M. Langridge, Daniel A. Lack, Thilina Jayarathne, Elizabeth A. Stone, Chelsea E. Stockwell, Robert J. Yokelson, Shane M. Murphy

Chemistry and Biochemistry Faculty Publications

A wide range of globally significant biomass fuels were burned during the fourth Fire Lab at Missoula Experiment (FLAME-4). A multi-channel photoacoustic absorption spectrometer (PAS) measured dry absorption at 405, 532, and 660 nm and thermally denuded (250 °C) absorption at 405 and 660 nm. Absorption coefficients were broken into contributions from black carbon (BC), brown carbon (BrC), and lensing following three different methodologies, with one extreme being a method that assumes the thermal denuder effectively removes organics and the other extreme being a method based on the assumption that black carbon (BC) has an Ångström exponent of unity. The …

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Multi-Instrument Comparison And Compilation Of Non-Methane Organic Gas Emissions From Biomass Burning And Implications For Smoke-Derived Secondary Organic Aerosol Precursors, Lindsay E. Hatch, Robert J. Yokelson, Chelsea E. Stockwell, Patrick R. Veres, Isobel J. Simpson, Donald R. Blake, John J. Orlando, Kelley C. Barsanti

Chemistry and Biochemistry Faculty Publications

Multiple trace-gas instruments were deployed during the fourth Fire Lab at Missoula Experiment (FLAME- 4), including the first application of proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOFMS) and comprehensive two-dimensional gas chromatography-time-offlight mass spectrometry (GC×GC-TOFMS) for laboratory biomass burning (BB) measurements. Open-path Fourier transform infrared spectroscopy (OP-FTIR) was also deployed, as well as whole-air sampling (WAS) with onedimensional gas chromatography-mass spectrometry (GCMS) analysis. This combination of instruments provided an unprecedented level of detection and chemical speciation. The chemical composition and emission factors (EFs) determined by these four analytical techniques were compared for four representative fuels. The results demonstrate that the instruments are …

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A Dual-Chamber Method For Quantifying The Effects Of Atmospheric Perturbations On Secondary Organic Aerosol Formation From Biomass Burning Emissions, Daniel S. Tkacik, Ellis S. Robinson, Adam Ahern, Rawad Saleh, Chelsea Stockwell, Patrick Veres, Isobel J. Simpson, Simone Meinardi, Donald R. Blake, Robert J. Yokelson, Albert A. Presto, Ryan C. Sullivan, Neil M. Donahue, Allen L. Robinson

Chemistry and Biochemistry Faculty Publications

Biomass burning (BB) is a major source of atmospheric pollutants. Field and laboratory studies indicate that secondary organic aerosol (SOA) formation from BB emissions is highly variable. We investigated sources of this variability using a novel dual-smog-chamber method that directly compares the SOA formation from the same BB emissions under two different atmospheric conditions. During each experiment, we filled two identical Teflon smog chambers simultaneously with BB emissions from the same fire. We then perturbed the smoke with UV lights, UV lights plus nitrous acid (HONO), or dark ozone in one or both chambers. These perturbations caused SOA formation in …

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In Situ Measurements Of Water Uptake By Black Carbon-Containing Aerosol In Wildfire Plumes, Anne E. Perring, Joshua P. Schwarz, Milos Z. Markovic, David W. Fahey, Jose L. Jimenez, Pedro Campuzano-Jost, Brett D. Palm, Armin Wisthaler, Tomas Mikoviny, Glenn Diskin, Glen Sachse, Luke Ziemba, Bruce Anderson, Taylor Shingler, Ewan Crosbie, Armin Sorooshian, Robert Yokelson, Ru Shan Gao

Chemistry and Biochemistry Faculty Publications

Water uptake by black carbon (BC)-containing aerosol was quantified in North American wildfire plumes of varying age (1 to ~40 h old) sampled during the SEAC4RS mission (2013). A Humidified Dual SP2 (HD-SP2) is used to optically size BC-containing particles under dry and humid conditions from which we extract the hygroscopicity parameter, κ, of materials internally mixed with BC. Instrumental variability and the uncertainty of the technique are briefly discussed. An ensemble average κ of 0.04 is found for the set of plumes sampled, consistent with previous estimates of bulk aerosol hygroscopicity from biomass burning sources. The temporal evolution of …

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Airborne Measurements Of Western U.S. Wildfire Emissions: Comparison With Prescribed Burning And Air Quality Implications, Xiaoxi Liu, L. Gregory Huey, Robert J. Yokelson, Vanessa Selimovic, Isobel J. Simpson, Markus Müller, Jose L. Jimenez, Pedro Campuzano-Jost, Andreas J. Beyersdorf, Donald R. Blake, Zachary Butterfield, Yonghoon Choi, John D. Crounse, Douglas A. Day, Glenn S. Diskin, Manvendra K. Dubey, Edward Fortner, Thomas F. Hanisco, Weiwei Hu, Laura E. King, Lawrence Kleinman, Simone Meinardi, Tomas Mikoviny, Timothy B. Onasch, Brett B. Palm, Jeff Peischl, Ilana B. Pollack, Thomas B. Ryerson, Glen W. Sachse, Arthur J. Sedlacek, John E. Shilling, Stephen Springston, Jason M. St. Clair

Chemistry and Biochemistry Faculty Publications

Wildfires emit significant amounts of pollutants that degrade air quality. Plumes from three wildfires in the western U.S. were measured from aircraft during the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) and the Biomass Burning Observation Project (BBOP), both in summer 2013. This study reports an extensive set of emission factors (EFs) for over 80 gases and 5 components of submicron particulate matter (PM1) from these temperate wildfires. These include rarely, or never before, measured oxygenated volatile organic compounds and multifunctional organic nitrates. The observed EFs are compared with previous measurements of temperate …

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Global Fire Emissions Estimates During 1997-2016, Guido R. Van Der Werf, James T. Randerson, Louis Giglio, Thijs T. Van Leeuwen, Yang Chen, Brendan M. Rogers, Mingquan Mu, Margreet J.E. Van Marle, Douglas C. Morton, G. James Collatz, Robert J. Yokelson, Prasad S. Kasibhatla

Chemistry and Biochemistry Faculty Publications

Special Issue: Intramolecular Hydrogen Bonding 2017, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

A Bipyridine-Ligated Zinc(Ii) Complex With Bridging Flavonolate Ligation: Synthesis, Characterization, And Visible-Light-Induced Co Release Reactivity, Shayne Sorenson, Marina Popova, Atta M. Arif, Lisa M. Berreau

Chemistry and Biochemistry Faculty Publications

Unraveling The Interactions Of The Physiological Reductant Flavodoxin With The Different Conformations Of The Fe Protein In The Nitrogenase Cycle, Natasha Pence, Monika Tokmina-Lukaszewska, Zhi-Yong Yang, Rhesa N. Ledbetter, Lance C. Seefeldt, Brian Bothner, John W. Peters

Chemistry and Biochemistry Faculty Publications

Chemistry and Biochemistry Faculty Publications

Chemistry and Biochemistry Faculty Publications

Chemistry and Biochemistry Faculty Publications

Chemistry and Biochemistry Faculty Publications

Chemistry and Biochemistry Faculty Publications