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- Biomass burning (12)
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- Savanna fires (4)
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- Viscosity (3)
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- Biomass fires (2)
- Coercive force (2)
- Colorectal cancer (2)
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Articles 61 - 90 of 202
Full-Text Articles in Biochemistry
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
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 …
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
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 …
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
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 …
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
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 …
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
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 …
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
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 …
Infrared Spectroscopy Of The Nitrogenase Mofe Protein Under Electrochemical Control: Potential-Triggered Co Binding, P. Paengnakorn, Philip A. Ash, Sudipta K. Shaw, Karamatullah Danyal, T. Chen, Dennis R. Dean, Lance C. Seefeldt, Kylie A. Vincent
Infrared Spectroscopy Of The Nitrogenase Mofe Protein Under Electrochemical Control: Potential-Triggered Co Binding, P. Paengnakorn, Philip A. Ash, Sudipta K. Shaw, Karamatullah Danyal, T. Chen, Dennis R. Dean, Lance C. Seefeldt, Kylie A. Vincent
Chemistry and Biochemistry Faculty Publications
We demonstrate electrochemical control of the nitrogenase MoFe protein, in the absence of Fe protein or ATP, using europium(III/II) polyaminocarboxylate complexes as electron transfer mediators. This allows the potential dependence of proton reduction and inhibitor (CO) binding to the active site FeMo-cofactor to be established. Reduction of protons to H2 is catalyzed by the wild type MoFe protein and Β-98Tyr→His and Β-99Phe→His variants of the MoFe protein at potentials more negative than -800 mV (vs. SHE), with greater electrocatalytic proton reduction rates observed for the variants compared to the wild type protein. Electrocatalytic proton reduction is strongly …
Emissions Of Nitrogen-Containing Organic Compounds From The Burning Of Herbaceous And Arboraceous Biomass: Fuel Composition Dependence And The Variability Of Commonly Used Nitrile Tracers, Matthew M. Coggon, Patrick R. Veres, Bin Yuan, Abigail Koss, Carsten Warneke, Jessica B. Gilman, Brian M. Lerner, Jeff Peischl, Kenneth C. Aikin, Chelsea E. Stockwell, Lindsay E. Hatch, Thomas B. Ryerson, James M. Roberts, Robert J. Yokelson, Joost A. De Gouw
Emissions Of Nitrogen-Containing Organic Compounds From The Burning Of Herbaceous And Arboraceous Biomass: Fuel Composition Dependence And The Variability Of Commonly Used Nitrile Tracers, Matthew M. Coggon, Patrick R. Veres, Bin Yuan, Abigail Koss, Carsten Warneke, Jessica B. Gilman, Brian M. Lerner, Jeff Peischl, Kenneth C. Aikin, Chelsea E. Stockwell, Lindsay E. Hatch, Thomas B. Ryerson, James M. Roberts, Robert J. Yokelson, Joost A. De Gouw
Chemistry and Biochemistry Faculty Publications
Volatile organic compounds (VOCs) emitted from residential wood and crop residue burning were measured in Colorado, U.S. When compared to the emissions from crop burning, residential wood burning exhibited markedly lower concentrations of acetonitrile, a commonly used biomass burning tracer. For both herbaceous and arboraceous fuels, the emissions of nitrogen-containing VOCs (NVOCs) strongly depend on the fuel nitrogen content; therefore, low NVOC emissions from residential wood burning result from the combustion of low-nitrogen fuel. Consequently, the emissions of compounds hazardous to human health, such as HNCO and HCN, and the formation of secondary pollutants, such as ozone generated by NOx, …
Field Measurements Of Trace Gases And Aerosols Emitted By Peat Fires In Central Kalimantan, Indonesia, During The 2015 El Niño, Chelsea E. Stockwell, Thilina Jayarathne, Mark A. Cochrane, Kevin C. Ryan, Erianto I. Putra, Bambang H. Saharjo, Ati D. Nurhayati, Israr Albar, Donald R. Blake, Isobel J. Simpson, Elizabeth A. Stone, Robert J. Yokelson
Field Measurements Of Trace Gases And Aerosols Emitted By Peat Fires In Central Kalimantan, Indonesia, During The 2015 El Niño, Chelsea E. Stockwell, Thilina Jayarathne, Mark A. Cochrane, Kevin C. Ryan, Erianto I. Putra, Bambang H. Saharjo, Ati D. Nurhayati, Israr Albar, Donald R. Blake, Isobel J. Simpson, Elizabeth A. Stone, Robert J. Yokelson
Chemistry and Biochemistry Faculty Publications
Peat fires in Southeast Asia have become a major annual source of trace gases and particles to the regional-global atmosphere. The assessment of their influence on atmospheric chemistry, climate, air quality, and health has been uncertain partly due to a lack of field measurements of the smoke characteristics. During the strong 2015 El Niño event we deployed a mobile smoke sampling team in the Indonesian province of Central Kalimantan on the island of Borneo and made the first, or rare, field measurements of trace gases, aerosol optical properties, and aerosol mass emissions for authentic peat fires burning at various depths …
Nepal Ambient Monitoring And Source Testing Experiment (Namaste): Emissions Of Trace Gases And Light-Absorbing Carbon From Wood And Dung Cooking Fires, Garbage And Crop Residue Burning, Brick Kilns, And Other Sources, Chelsea E. Stockwell, Ted J. Christian, J. Douglas Goetz, Thilina Jayarathne, Prakash V. Bhave, Puppala S. Praveen, Sagar Adhikari, Rashmi Maharjan, Peter F. Decarlo, Elizabeth A. Stone, Eri Saikawa, Donald R. Blake, Isobel J. Simpson, Robert J. Yokelson, Arnico K. Panday
Nepal Ambient Monitoring And Source Testing Experiment (Namaste): Emissions Of Trace Gases And Light-Absorbing Carbon From Wood And Dung Cooking Fires, Garbage And Crop Residue Burning, Brick Kilns, And Other Sources, Chelsea E. Stockwell, Ted J. Christian, J. Douglas Goetz, Thilina Jayarathne, Prakash V. Bhave, Puppala S. Praveen, Sagar Adhikari, Rashmi Maharjan, Peter F. Decarlo, Elizabeth A. Stone, Eri Saikawa, Donald R. Blake, Isobel J. Simpson, Robert J. Yokelson, Arnico K. Panday
Chemistry and Biochemistry Faculty Publications
The Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) campaign took place in and around the Kathmandu Valley and in the Indo-Gangetic Plain (IGP) of southern Nepal during April 2015. The source characterization phase targeted numerous important but undersampled (and often inefficient) combustion sources that are widespread in the developing world such as cooking with a variety of stoves and solid fuels, brick kilns, open burning of municipal solid waste (a.k.a. trash or garbage burning), crop residue burning, generators, irrigation pumps, and motorcycles. NAMaSTE produced the first, or rare, measurements of aerosol optical properties, aerosol mass, and detailed trace gas …
Interactions Of Nucleic Acid Bases With Temozolomide. Stacked, Perpendicular, And Coplanar Heterodimers, Okuma Emile Kasende, Steve Scheiner
Interactions Of Nucleic Acid Bases With Temozolomide. Stacked, Perpendicular, And Coplanar Heterodimers, Okuma Emile Kasende, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Temozolomide (TMZ) was paired with each of the five nucleic acid bases, and the potential energy surface searched for all minima, in the context of dispersion-corrected density functional theory and MP2 methods. Three types of arrangements were observed, with competitive stabilities. Coplanar H-bonding structures, reminiscent of Watson–Crick base pairs were typically the lowest in energy, albeit by a small amount. Also very stable were perpendicular arrangements that included one or more H-bonds. The two monomers were stacked approximately parallel to one another in the third category, some of which contained weak and distorted H-bonds. Dispersion was found to be a …
Monitoring The Charge Distribution During Proton And Sodium Ion Conduction Along Chains Of Water Molecules And Protein Residues, Steve Scheiner
Monitoring The Charge Distribution During Proton And Sodium Ion Conduction Along Chains Of Water Molecules And Protein Residues, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Quantum calculations are used to determine the level of delocalization of the charge of a cation as it translates along a chain of water molecules or glycine residues. Charge dispersal is monitored via the molecular electrostatic potential and the dipole moment of the entire system. The positive charge is largely localized on the water molecule on which the proton is situated, but becomes more intense and extended as the proton moves along the chain. The positive charge is more delocalized in protonated polyglycine, where it extends over at least an entire residue. Displacement of the proton along the chain intensifies …
Parameterization Of Single-Scattering Albedo (Ssa) And Absorption Ångström Exponent (Aae) With Ec/Oc For Aerosol Emissions From Biomass Burning, Rudra P. Pokhrel, Nick L. Wagner, Justin M. Langridge, Daniel A. Lack, Thilina Jayarathne, Elizabeth A. Stone, Chelsea E. Stockwell, Robert J. Yokelson, Shane M. Murphy
Parameterization Of Single-Scattering Albedo (Ssa) And Absorption Ångström Exponent (Aae) With Ec/Oc For Aerosol Emissions From Biomass Burning, Rudra P. Pokhrel, 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
Single-scattering albedo (SSA) and absorption Ångström exponent (AAE) are two critical parameters in determining the impact of absorbing aerosol on the Earth's radiative balance. Aerosol emitted by biomass burning represent a significant fraction of absorbing aerosol globally, but it remains difficult to accurately predict SSA and AAE for biomass burning aerosol. Black carbon (BC), brown carbon (BrC), and non-absorbing coatings all make substantial contributions to the absorption coefficient of biomass burning aerosol. SSA and AAE cannot be directly predicted based on fuel type because they depend strongly on burn conditions. It has been suggested that SSA can be effectively parameterized …
Agricultural Fires In The Southeastern U.S. During Seac4Rs: Emissions Of Trace Gases And Particles And Evolution Of Ozone, Reactive Nitrogen, And Organic Aerosol, Xiaoxi Liu, Y. Zhang, L. G. Huey, R. J. Yokelson, Y. Wang, J. L. Jimenez, P. Campuzano-Jost, A. J. Beyersdorf, D. R. Blake, Y. Choi, J. M. St. Clair, J. D. Crounse, D. A. Day, G. S. Diskin, A. Ried, S. R. Hall, T. F. Hanisco, L. E. King, S. Meinardi, T. Mikoviny, B. B. Palm, J. Peischl, A. E. Perring, I. B. Pollack, T. B. Ryerson, G. Sachse, J. P. Schwarz, I. J. Simpson, D. J. Tanner, K. L. Thornhil, K. Ullmann, R. J. Weber, P. O. Wennberg
Agricultural Fires In The Southeastern U.S. During Seac4Rs: Emissions Of Trace Gases And Particles And Evolution Of Ozone, Reactive Nitrogen, And Organic Aerosol, Xiaoxi Liu, Y. Zhang, L. G. Huey, R. J. Yokelson, Y. Wang, J. L. Jimenez, P. Campuzano-Jost, A. J. Beyersdorf, D. R. Blake, Y. Choi, J. M. St. Clair, J. D. Crounse, D. A. Day, G. S. Diskin, A. Ried, S. R. Hall, T. F. Hanisco, L. E. King, S. Meinardi, T. Mikoviny, B. B. Palm, J. Peischl, A. E. Perring, I. B. Pollack, T. B. Ryerson, G. Sachse, J. P. Schwarz, I. J. Simpson, D. J. Tanner, K. L. Thornhil, K. Ullmann, R. J. Weber, P. O. Wennberg
Chemistry and Biochemistry Faculty Publications
Emissions from 15 agricultural fires in the southeastern U.S. were measured from the NASA DC-8 research aircraft during the summer 2013 Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign. This study reports a detailed set of emission factors (EFs) for 25 trace gases and 6 fine particle species. The chemical evolution of the primary emissions in seven plumes was examined in detail for ~1.2 h. A Lagrangian plume cross-section model was used to simulate the evolution of ozone (O3), reactive nitrogen species, and organic aerosol (OA). Observed EFs are generally consistent with previous …
Planning, Implementation, And Scientific Goals Of The Studies Of Emissions And Atmospheric Composition, Clouds And Climate Coupling By Regional Surveys (Seac4Rs) Field Mission, Owen B. Toon, Hal Maring, Jack Dibb, Richard Ferrare, Daniel J. Jacob, Eric J. Jensen, Z. Johnny Luo, Gerald G. Mace, Laura L. Pan, Lenny Pfister, Karen H. Rosenlof, Jens Redemann, Jeffrey S. Reid, Hanwant B. Singh, Anne M. Thompson, Robert Yokelson, Patrick Minnis, Gao Chen, Kenneth W. Jucks, Alex Pszenny
Planning, Implementation, And Scientific Goals Of The Studies Of Emissions And Atmospheric Composition, Clouds And Climate Coupling By Regional Surveys (Seac4Rs) Field Mission, Owen B. Toon, Hal Maring, Jack Dibb, Richard Ferrare, Daniel J. Jacob, Eric J. Jensen, Z. Johnny Luo, Gerald G. Mace, Laura L. Pan, Lenny Pfister, Karen H. Rosenlof, Jens Redemann, Jeffrey S. Reid, Hanwant B. Singh, Anne M. Thompson, Robert Yokelson, Patrick Minnis, Gao Chen, Kenneth W. Jucks, Alex Pszenny
Chemistry and Biochemistry Faculty Publications
The Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) fieldmission based at Ellington Field, Texas, during August and September 2013 employed the most comprehensive airborne payload to date to investigate atmospheric composition over North America. The NASA ER-2, DC-8, and SPEC Inc. Learjet flew 57 science flights fromthe surface to 20 km. The ER-2 employed seven remote sensing instruments as a satellite surrogate and eight in situ instruments. The DC-8 employed 23 in situ and five remote sensing instruments for radiation, chemistry, and microphysics. The Learjet used 11 instruments to explore cloud microphysics. SEAC4RS …
Ice-Nucleating Particle Emissions From Biomass Combustion And The Potential Importance Of Soot Aerosol, E. J.T. Levin, G. R. Mcmeeking, P. J. Demott, C. S. Mccluskey, C. M. Carrico, S. Nakao, T. Jayarathne, E. A. Stone, C. E. Stockwell, R. J. Yokelson, S. M. Kreidenweis
Ice-Nucleating Particle Emissions From Biomass Combustion And The Potential Importance Of Soot Aerosol, E. J.T. Levin, G. R. Mcmeeking, P. J. Demott, C. S. Mccluskey, C. M. Carrico, S. Nakao, T. Jayarathne, E. A. Stone, C. E. Stockwell, R. J. Yokelson, S. M. Kreidenweis
Chemistry and Biochemistry Faculty Publications
Ice-nucleating particles (INPs) are required for initial ice crystal formation in clouds at temperatures warmer than about -36°C and thus play a crucial role in cloud and precipitation formation. Biomass burning has been found to be a source of INPs in previous studies and is also a major contributor to atmospheric black carbon (BC) concentrations. This study focuses on isolating the BC contribution to the INP population associated with biomass combustion. Emissions of condensation mode INPs from a number of globally relevant biomass fuels were measured at -30°C and above water saturation as fires progressed from ignition to extinguishment in …
Rapidly Evolving Ultrafine And Fine Mode Biomass Smoke Physical Properties: Comparing Laboratory And Field Results, Christian M. Carrico, Anthony J. Prenni, Sonia M. Kreidenweis, Ezra J.T. Levin, Christina S. Mccluskey, Paul J. Demott, Gavin R. Mcmeeking, Shunsuke Nakao, Chelsea Stockwell, Robert J. Yokelson
Rapidly Evolving Ultrafine And Fine Mode Biomass Smoke Physical Properties: Comparing Laboratory And Field Results, Christian M. Carrico, Anthony J. Prenni, Sonia M. Kreidenweis, Ezra J.T. Levin, Christina S. Mccluskey, Paul J. Demott, Gavin R. Mcmeeking, Shunsuke Nakao, Chelsea Stockwell, Robert J. Yokelson
Chemistry and Biochemistry Faculty Publications
Combining field and laboratory results, we present biomass smoke physical properties. We report sub-0.56 µm diameter (Dp) particle sizing (fast mobility particle sizer, FMPS) plus light absorption and scattering at 870nm (photoacoustic extinctiometer). For Dp<200 >nm, the FMPS characterized sizing within ±20% compared to standards. As compared to the traditional scanning mobility particle sizer, the FMPS responded most accurately to single-mode polydispersions with mean Dp<200 >nm, which characterized the smoke sampled here. Smoke was measured from laboratory fresh emissions (seconds to hours old), the High Park Fire (hours to<1 >day), and from regional biomass burning (several days). During a High …
A Disease Spectrum For Itpa Variation: Advances In Biochemical And Clinical Research, Nicholas E. Burgis
A Disease Spectrum For Itpa Variation: Advances In Biochemical And Clinical Research, Nicholas E. Burgis
Chemistry and Biochemistry Faculty Publications
Human ITPase (encoded by the ITPA gene) is a protective enzyme which acts to exclude noncanonical (deoxy) nucleoside triphosphates ((d)NTPs) such as (deoxy)inosine 5′-triphosphate ((d)ITP), from (d)NTP pools. Until the last few years, the importance of ITPase in human health and disease has been enigmatic. In 2009, an article was published demonstrating that ITPase deficiency in mice is lethal. All homozygous null offspring died before weaning as a result of cardiomyopathy due to a defect in the maintenance of quality ATP pools. More recently, a whole exome sequencing project revealed that very rare, severe human ITPA mutation results in early …
Microsolvation Of Anions By Molecules Forming Ch∙∙X- Hydrogen Bonds, Steve Scheiner, Binod Nepal
Microsolvation Of Anions By Molecules Forming Ch∙∙X- Hydrogen Bonds, Steve Scheiner, Binod Nepal
Chemistry and Biochemistry Faculty Publications
Various anions were surrounded by n molecules of CF3H, which was used as a prototype CH donor solvent, and the structures and energies studied by M06-2X calculations with a 6-31+G∗∗ basis set. Anions considered included the halides F-, Cl-, Br- and I-, as well as those with multiple proton acceptor sites: CN-, NO3 -, HCOO-, CH3COO-, HSO4 -, H2PO4 -, and anions with higher charges SO4 2-, HPO4 2- and PO4 …
In Situ Measurements And Modeling Of Reactive Trace Gases In A Small Biomass Burning Plume, M. Muller, B. Anderson, A. Beyersdorf, J. H. Crawford, G. Diskin, P. Eichler, A. Fried, F. N. Keutsch, T. Mikoviny, K. L. Thornhill, J. G. Walega, A. J. Weinheimer, M. Yang, Robert Yokelson, A. Wisthaler
In Situ Measurements And Modeling Of Reactive Trace Gases In A Small Biomass Burning Plume, M. Muller, B. Anderson, A. Beyersdorf, J. H. Crawford, G. Diskin, P. Eichler, A. Fried, F. N. Keutsch, T. Mikoviny, K. L. Thornhill, J. G. Walega, A. J. Weinheimer, M. Yang, Robert Yokelson, A. Wisthaler
Chemistry and Biochemistry Faculty Publications
An instrumented NASA P-3B aircraft was used for airborne sampling of trace gases in a plume that had emanated from a small forest understory fire in Georgia, USA. The plume was sampled at its origin for deriving emission factors and followed ~ 13.6 km downwind for observing chemical changes during the first hour of atmospheric aging. The P-3B payload included a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS), which measured non-methane organic gases (NMOGs) at unprecidented spatio-temporal resolution (10m/0.1 s). Quantitative emission data are reported for CO2, CO, NO, NO2, HONO, NH3 and 16 NMOGs (formaldehyde, methanol, …
Cobalt-Centred Boron Molecular Drums With The Highest Coordination Number In The Cob16− Cluster, Ivan A. Popov, Tian Jian, Gary V. Lopez, Alexander I. Boldyrev, Lai-Sheng Wang
Cobalt-Centred Boron Molecular Drums With The Highest Coordination Number In The Cob16− Cluster, Ivan A. Popov, Tian Jian, Gary V. Lopez, Alexander I. Boldyrev, Lai-Sheng Wang
Chemistry and Biochemistry Faculty Publications
The electron deficiency and strong bonding capacity of boron have led to a vast variety of molecular structures in chemistry and materials science. Here we report the observation of highly symmetric cobalt-centered boron drum-like structures of CoB16−, characterized by photoelectron spectroscopy and ab initio calculations. The photoelectron spectra display a relatively simple spectral pattern, suggesting a high symmetry structure. Two nearly degenerate isomers with D8d(I) and C4v (II) symmetries are found computationally to compete for the global minimum. These drum-like structures consist of two B8 rings sandwiching a cobalt atom, which has the highest …
Biomass Burning Emissions And Potential Air Quality Impacts Of Volatile Organic Compounds And Other Trace Gases From Temperate Fuels Common In The United States, J. B. Gilman, B. M. Lerner, W. C. Kuster, P. D. Goldan, C. Warneke, P. R. Veres, J. M. Roberts, J. A. De Gouw, I. R. Burling, Robert Yokelson
Biomass Burning Emissions And Potential Air Quality Impacts Of Volatile Organic Compounds And Other Trace Gases From Temperate Fuels Common In The United States, J. B. Gilman, B. M. Lerner, W. C. Kuster, P. D. Goldan, C. Warneke, P. R. Veres, J. M. Roberts, J. A. De Gouw, I. R. Burling, Robert Yokelson
Chemistry and Biochemistry Faculty Publications
A comprehensive suite of instruments was used to quantify the emissions of over 200 organic gases, including methane and volatile organic compounds (VOCs), and 9 inorganic gases from 56 laboratory burns of 18 different biomass fuel types common in the southeastern, southwestern, or northern United States. A gas chromatograph-mass spectrometer (GC-MS) provided extensive chemical detail of discrete air samples collected during a laboratory burn and was complemented by real-time measurements of organic and inorganic species via an open-path Fourier transform infrared spectrometer (OP-FTIR) and 3 different chemical ionization-mass spectrometers. These measurements were conducted in February 2009 at the U.S. Department …
Investigating The Links Between Ozone And Organic Aerosol Chemistry In A Biomass Burning Plume From A Prescribed Fire In California Chaparral, M. J. Alvarado, C. R. Lonsdale, Robert Yokelson, Sheryl Kashi Akagi, H. Coe, J. S. Craven, E. V. Fischer, G. R. Mcmeeking, J. H. Seinfeld, T. Soni, J. W. Taylor, D. R. Weise, C. E. Wold
Investigating The Links Between Ozone And Organic Aerosol Chemistry In A Biomass Burning Plume From A Prescribed Fire In California Chaparral, M. J. Alvarado, C. R. Lonsdale, Robert Yokelson, Sheryl Kashi Akagi, H. Coe, J. S. Craven, E. V. Fischer, G. R. Mcmeeking, J. H. Seinfeld, T. Soni, J. W. Taylor, D. R. Weise, C. E. Wold
Chemistry and Biochemistry Faculty Publications
Within minutes after emission, complex photochemistry in biomass burning smoke plumes can cause large changes in the concentrations of ozone (O3) and organic aerosol (OA). Being able to understand and simulate this rapid chemical evolution under a wide variety of conditions is a critical part of forecasting the impact of these fires on air quality, atmospheric composition, and climate. Here we use version 2.1 of the Aerosol Simulation Program (ASP) to simulate the evolution of O3 and secondary organic aerosol (SOA) within a young biomass burning smoke plume from the Williams prescribed fire in chaparral, which was sampled over …
Revealing Important Nocturnal And Day-To-Day Variations In Fire Smoke Emissions Through A Multiplatform Inversion, Pablo E. Saide, David A. Peterson, Arlindo Da Silva, Bruce Anderson, Luke D. Ziemba, Glenn Diskin, Glen Sachse, Johnathan Hair, Carolyn Butler, Marta Fenn, Jose L. Jimenez, Pedro Campuzano-Jost, Anne E. Perring, Joshua P. Schwarz, Milos Z. Markovic, Phil Russell, Jens Redemann, Yohei Shinozuka, David G. Streets, Fang Yan, Jack Dibb, Robert Yokelson, O. Brian Toon, Edward Hyer, Gregory R. Carmichael
Revealing Important Nocturnal And Day-To-Day Variations In Fire Smoke Emissions Through A Multiplatform Inversion, Pablo E. Saide, David A. Peterson, Arlindo Da Silva, Bruce Anderson, Luke D. Ziemba, Glenn Diskin, Glen Sachse, Johnathan Hair, Carolyn Butler, Marta Fenn, Jose L. Jimenez, Pedro Campuzano-Jost, Anne E. Perring, Joshua P. Schwarz, Milos Z. Markovic, Phil Russell, Jens Redemann, Yohei Shinozuka, David G. Streets, Fang Yan, Jack Dibb, Robert Yokelson, O. Brian Toon, Edward Hyer, Gregory R. Carmichael
Chemistry and Biochemistry Faculty Publications
We couple airborne, ground-based, and satellite observations; conduct regional simulations; and develop and apply an inversion technique to constrain hourly smoke emissions from the Rim Fire, the third largest observed in California, USA. Emissions constrainedwithmultiplatform data show notable nocturnal enhancements (sometimes over a factor of 20), correlate better with daily burned area data, and are a factor of 2–4 higher than a priori estimates, highlighting the need for improved characterization of diurnal profiles and day-to-day variability when modeling extreme fires. Constraining only with satellite data results in smaller enhancements mainly due to missing retrievals near the emissions source, suggesting that …
The Infrared Spectrum Of The He-C2d2 Complex, N. Moazzen-Ahmadi, A. R. W. Mckellar, Berta Fernandez, David Farrelly
The Infrared Spectrum Of The He-C2d2 Complex, N. Moazzen-Ahmadi, A. R. W. Mckellar, Berta Fernandez, David Farrelly
Chemistry and Biochemistry Faculty Publications
Spectra of the helium-acetylene complex are elusive because this weakly bound system lies close to the free rotor limit. Previously, limited assignments of He–C2D2 transitions in the R(0) region of the ν3 fundamental band (≈2440 cm−1) were published. Here, new He–C2D2 infrared spectra of this band are obtained using a tunable optical parametric oscillator laser source to probe a pulsed supersonic slit jet expansion from a cooled nozzle, and the analysis is extended to the weaker and more difficult P(1) and R(1) regions. A term value approach is used to obtain a consistent set of “experimental” energy levels. …
Identification And Quantification Of Gaseous Organic Compounds Emitted From Biomass Burning Using Two-Dimensional Gas Chromatography–Time-Of-Flight Mass Spectrometry, L. E. Hatch, W. Luo, J. F. Pankow, Robert Yokelson, C. Stockwell, K. C. Barsanti
Identification And Quantification Of Gaseous Organic Compounds Emitted From Biomass Burning Using Two-Dimensional Gas Chromatography–Time-Of-Flight Mass Spectrometry, L. E. Hatch, W. Luo, J. F. Pankow, Robert Yokelson, C. Stockwell, K. C. Barsanti
Chemistry and Biochemistry Faculty Publications
The current understanding of secondary organic aerosol (SOA) formation within biomass burning (BB) plumes is limited by the incomplete identification and quantification of the non-methane organic compounds (NMOCs) emitted from such fires. Gaseous organic compounds were collected on sorbent cartridges during laboratory burns as part of the fourth Fire Lab at Missoula Experiment (FLAME-4) and analyzed by two-dimensional gas chromatography-time-of-flight mass spectrometry (GC x GC-ToFMS). The sensitivity and resolving power of GC x GC-ToFMS allowed the acquisition of the most extensive data set of BB NMOCs to date, with measurements from 708 positively or tentatively identified compounds. Estimated emission factors …
Intramolecular S···O Chalcogen Bond As Stabilizing Factor In Geometry Of Substituted Phenyl-Sf3 Molecules, Vincent De Paul Nziko, Steve Scheiner
Intramolecular S···O Chalcogen Bond As Stabilizing Factor In Geometry Of Substituted Phenyl-Sf3 Molecules, Vincent De Paul Nziko, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Density functional methods are used to examine the geometries and energetics of molecules containing a phenyl ring joined to the trigonal bipyramidal SF3 framework. The phenyl ring has a strong preference for an equatorial position. This preference remains when one or two ether -CH2OCH3 groups are added to the phenyl ring, ortho to SF3, wherein an apical structure lies nearly 30 kcal/mol higher in energy. Whether equatorial or apical, the molecule is stabilized by a S···O chalcogen bond, sometimes augmented by CH···F or CH···O H-bonds. The strength of the intramolecular S···O bond is estimated to lie in the range between …
Characterization Of Biomass Burning Emissions From Cooking Fires, Peat, Crop Residue, And Other Fuels With High-Resolution Proton-Transfer-Reaction Time-Of-Flight Mass Spectrometry, C. Stockwell, P. Veres, J. Williams
Characterization Of Biomass Burning Emissions From Cooking Fires, Peat, Crop Residue, And Other Fuels With High-Resolution Proton-Transfer-Reaction Time-Of-Flight Mass Spectrometry, C. Stockwell, P. Veres, J. Williams
Chemistry and Biochemistry Faculty Publications
We deployed a high-resolution proton-transferreaction time-of-flight mass spectrometer (PTR-TOF-MS) to measure biomass-burning emissions from peat, crop residue, cooking fires, and many other fire types during the fourth Fire Lab at Missoula Experiment (FLAME-4) laboratory campaign. A combination of gas standard calibrations and composition sensitive, mass-dependent calibration curves was applied to quantify gas-phase non-methane organic compounds (NMOCs) observed in the complex mixture of fire emissions. We used several approaches to assign the best identities to most major “exact masses”, including many high molecular mass species. Using these methods, approximately 80–96% of the total NMOC mass detected by the PTR-TOFMS and Fourier …
Observations And Analysis Of Organic Aerosol Evolution In Some Prescribed Fire Smoke Plumes, A. A. May, T. Lee, G. R. Mcmeeking, Sheryl Kashi Akagi, A. P. Sullivan, S. P. Urbanski, Robert Yokelson, S. M. Kreidenweis
Observations And Analysis Of Organic Aerosol Evolution In Some Prescribed Fire Smoke Plumes, A. A. May, T. Lee, G. R. Mcmeeking, Sheryl Kashi Akagi, A. P. Sullivan, S. P. Urbanski, Robert Yokelson, S. M. Kreidenweis
Chemistry and Biochemistry Faculty Publications
Open biomass burning is a significant source of primary air pollutants such as particulate matter and non-methane organic gases. However, the physical and chemical atmospheric processing of these emissions during transport is poorly understood. Atmospheric 5 transformations of biomass burning emissions have been investigated in environmental chambers, but there have been limited opportunities to investigate these transformations in the atmosphere. In this study, we deployed a suite of real-time instrumentation on a Twin Otter aircraft to sample smoke from prescribed fires in South Carolina, conducting measurements at both the source and downwind to character10 ize smoke evolution with atmospheric aging. …
Investigating The Links Between Ozone And Organic Aerosol Chemistry In A Biomass Burning Plume From A Prescribed Fire In California Chaparral, M. J. Alvarado, C. R. Lonsdale, Robert Yokelson, S. K. Akagi, H. Coe, J. S. Craven, E. V. Fischer, G. R. Mcmeeking, J. H. Seinfeld, T. Soni, J. W. Taylor, D. R. Weise, C. E. Wold
Investigating The Links Between Ozone And Organic Aerosol Chemistry In A Biomass Burning Plume From A Prescribed Fire In California Chaparral, M. J. Alvarado, C. R. Lonsdale, Robert Yokelson, S. K. Akagi, H. Coe, J. S. Craven, E. V. Fischer, G. R. Mcmeeking, J. H. Seinfeld, T. Soni, J. W. Taylor, D. R. Weise, C. E. Wold
Chemistry and Biochemistry Faculty Publications
Within minutes after emission, rapid, complex photochemistry within a biomass burning smoke plume can cause large changes in the concentrations of ozone (O3) and organic aerosol (OA). Being able to understand and simulate this rapid chemical evolution under a wide variety of conditions is a critical part of forecasting the impact of these fires on air quality, atmospheric composition, and climate. Here we use version 2.1 of the Aerosol Simulation Program (ASP) to simulate the evolution of O3 and secondary organic aerosol (SOA) within a young biomass burning smoke plume from the Williams prescribed burn in chaparral, …