Life Sciences | Open Access Articles | Digital Commons Network™

Rapid Evolution Of Aerosol Particles And Their Optical Properties Downwind Of Wildfires In The Western Us, Lawrence I. Kleinman, Arthur J. Sedlacek, Kouji Adachi, Peter R. Buseck, Sonya Collier, Manvendra K. Dubey, Anna L. Hodshire, Ernie Lewis, Timothy B. Onasch, Jeffery R. Pierce, John Shilling, Stephen R. Springston, Jian Wang, Qi Zhang, Shan Zhou, Robert J. Yokelson

Chemistry and Biochemistry Faculty Publications

During the first phase of the Biomass Burn Operational Project (BBOP) field campaign, conducted in the Pacific Northwest, the DOE G-1 aircraft was used to follow the time evolution of wildfire smoke from near the point of emission to locations 2-3.5 h downwind. In nine flights we made repeated transects of wildfire plumes at varying downwind distances and could thereby follow the plume's time evolution. On average there was little change in dilution-normalized aerosol mass concentration as a function of downwind distance. This consistency hides a dynamic system in which primary aerosol particles are evaporating and secondary ones condensing. Organic …

Go to article

Aerosol Mass And Optical Properties, Smoke Influence On O3, And High No3 Production Rates In A Western U.S. City Impacted By Wildfires, Vanessa Selimovic, Robert J. Yokelson, Gavin R. Mcmeeking, Sarah Coefield

Chemistry and Biochemistry Faculty Publications

Evaluating our understanding of smoke from wild and prescribed fires can benefit from downwind measurements that include inert tracers to test production and transport and reactive species to test chemical mechanisms. We characterized smoke from fires in coniferous forest fuels for >1,000 hr over two summers (2017 and 2018) at our Missoula, Montana, surface station and found a narrow range for key properties. ΔPM2.5/ΔCO was 0.1070 ± 0.0278 (g/g) or about half the age-independent ratios obtained at free troposphere elevations (0.2348 ± 0.0326). The average absorption Ångström exponent across both years was 1.84 ± 0.18, or about half the values …

Go to article

Influence Of Edge Effects On Laser-Induced Surface Displacement Of Opaque Materials By Photothermal Interferometry, G. A. S. Flizikowski, B. Anghinoni, J. H. Rohling, M. P. Belançon, R. S. Mendes, M. L. Baesso, L. C. Malacarne, T. Požar, Stephen E. Bialkowski, N. G. C. Astrath

Chemistry and Biochemistry Faculty Publications

We demonstrate the influence of edge effects on the photothermal-induced phase shift measured by a homodyne quadrature laser interferometer and compare the experiments with rigorous theoretical descriptions of thermoelastic surface displacement of metals. The finite geometry of the samples is crucial in determining how the temperature is distributed across the material and how this affects the interferometer phase shift measurements. The optical path change due to the surface thermoelastic deformation and thermal lens in the surrounding air is decoded from the interferometric signal using analytical and numerical tools. The boundary/edge effects are found to be relevant to properly describe the …

Go to article

The Nitrogen Budget Of Laboratory-Simulated Western Us Wildfires During The Firex 2016 Fire Lab Study, James M. Roberts, Chelsea E. Stockwell, Robert J. Yokelson, Joost De Gouw, Yong Liu, Vanessa Selimovic, Abigail R. Koss, Kanako Sekimoto, Matthew M. Coggon, Bin Yuan, Kyle J. Zarzana, Steven S. Brown, Cristina Santin, Stefan H. Doerr, Carsten Warneke

Chemistry and Biochemistry Faculty Publications

Reactive nitrogen (Nr, defined as all nitrogencontaining compounds except for N2 and N2O) is one of the most important classes of compounds emitted from wildfire, as Nr impacts both atmospheric oxidation processes and particle formation chemistry. In addition, several Nr compounds can contribute to health impacts from wildfires. Understanding the impacts of wildfire on the atmosphere requires a thorough description of Nr emissions. Total reactive nitrogen was measured by catalytic conversion to NO and detection by NO-O3 chemiluminescence together with individual Nr species during a series of laboratory fires of fuels characteristic of western US wildfires, conducted as part of …

Go to article

Comparison Of Accelerated Solvent Extraction (Ase) And Energized Dispersive Guided Extraction (Edge) For The Analysis Of Pesticides In Leaves, Ashlie D. Kinross, Kimberly J. Hageman, William J. Doucette, Alexandria L. Foster

Chemistry and Biochemistry Faculty Publications

Various techniques have been evaluated for the extraction and cleanup of pesticides from environmental samples. In this work, a Selective Pressurized Liquid Extraction (SPLE) method for pesticides was developed using a Thermo Fisher Scientific Accelerated Solvent Extraction (ASE) system. This instrument was compared to the newly introduced (2017) extraction instrument, the Energized Dispersive Guided Extraction (EDGE) system, which combines Pressurized Liquid Extraction (PLE) and dispersive Solid Phase Extraction (dSPE). We first optimized the SPLE method using the ASE instrument for pesticide extraction from alfalfa leaves using layers of Florisil and graphitized carbon black (GCB) downstream of the leaf homogenate in …

Go to article

Influence Of Adjuvants On Pesticide Soil-Air Partition Coefficients: Laboratory Measurements And Predicted Effects On Volatilization, Supta Das, Kimberly J. Hageman

Chemistry and Biochemistry Faculty Publications

A solid-phase fugacity meter was used to measure the soil–air partition coefficients of three semivolatile pesticides (chlorpyrifos, pyrimethanil, and trifluralin) in the absence of additional adjuvants (K_{soil–air,AI}), as part of commercial formulations (K_{soil–air,formulation}), and as formulation mixtures with an additional spray adjuvant added (K_{soil–air,formulation+spray adjuvant}). Chlorpyrifos K_{soil–air,formulation} values were also measured over 15–30 °C, allowing for the change in internal energy of the phase transfer reaction (Δ_soil–airU) to be calculated and compared to the Δ_soil–airU for K_{soil–air,AI} from the literature. Measured K_soil–air values …

Go to article

N3-Ligated Nickel(Ii) Diketonate Complexes: Synthesis, Characterization And Evaluation Of O2 Reactivity, Josiah G. D. Elsberg, Austin Peterson, Amy L. Fuller, Lisa M. Berreau

Chemistry and Biochemistry Faculty Publications

Interest in O₂-dependent aliphatic carbon–carbon (C–C) bond cleavage reactions of first row divalent metal diketonate complexes stems from the desire to further understand the reaction pathways of enzymes such as DKE1 and to extract information to develop applications in organic synthesis. A recent report of O₂-dependent aliphatic C–C bond cleavage at ambient temperature in Ni(II) diketonate complexes supported by a tridentate nitrogen donor ligand [(MBBP)Ni(PhC(O)CHC(O)Ph)]Cl (7-Cl; MBBP = 2,6-bis(1-methylbenzimidazol-2-yl)pyridine) in the presence of NEt₃ spurred our interest in further examining the chemistry of such complexes. A series of new TERPY-ligated Ni(II) diketonate complexes of the …

Go to article

Modeling The Alkaline Hydrolysis Of Diaryl Sulfate Diesters: A Mechanistic Study, Klaudia Szeler, Nicholas H. Williams, Alvan C. Hengge, Shina C. Kamerlin

Chemistry and Biochemistry Faculty Publications

Phosphate and sulfate esters have important roles in regulating cellular processes. However, while there has been substantial experimental and computational investigation of the mechanisms and the transition states involved in phosphate ester hydrolysis, there is far less work on sulfate ester hydrolysis. Here, we report a detailed computational study of the alkaline hydrolysis of diaryl sulfate diesters, using different DFT functionals as well as mixed implicit/explicit solvation with varying numbers of explicit water molecules. We consider the impact of the computational model on computed linear free-energy relationships (LFER) and the nature of the transition states (TS) involved. We obtain good …

Go to article

Ambient Air Quality In The Kathmandu Valley, Nepal, During The Pre-Monsoon: Concentrations And Sources Of Particulate Matter And Trace Gases, Md Robiul Islam, Thilina Jayarathne, Isobel J. Simpson, Benjamin Werden, John Maben, Ashley Gilbert, Puppala S. Praveen, Sagar Adhikari, Arnico K. Panday, Maheswar Rupakheti, Donald R. Blake, Robert J. Yokelson, Peter F. Decarlo, William C. Keene, Elizabeth A. Stone

Chemistry and Biochemistry Faculty Publications

The Kathmandu Valley in Nepal is a bowl-shaped urban basin that experiences severe air pollution that poses health risks to its 3.5 million inhabitants. As part of the Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE), ambient air quality in the Kathmandu Valley was investigated from 11 to 24 April 2015, during the premonsoon season. Ambient concentrations of fine and coarse particulate matter (PM2:5 and PM10, respectively), online PM1, inorganic trace gases (NH3, HNO3, SO2, and HCl), and carbon-containing gases (CO2, CO, CH4, and 93 nonmethane volatile organic compounds; NMVOCs) were quantified at a semi-urban location near the center of …

Go to article

Molecular Composition And Photochemical Lifetimes Of Brown Carbon Chromophores In Biomass Burning Organic Aerosol, Lauren T. Fleming, Peng Lin, James M. Roberts, Vanessa Selimovic, Robert Yokelson, Julia Laskin, Alexander Laskin, Sergey A. Nizkorodov

Chemistry and Biochemistry Faculty Publications

To better understand the effects of wildfires on air quality and climate, it is important to assess the occurrence of chromophoric compounds in smoke and characterize their optical properties. This study explores the molecular composition of light-absorbing organic aerosol, or brown carbon (BrC), sampled at the Missoula Fire Sciences laboratory as a part of the FIREX Fall 2016 lab intensive. A total of 12 biomass fuels from different plant types were tested, including gymnosperm (coniferous) and angiosperm (flowering) plants and different ecosystem components such as duff, litter, and canopy. Emitted biomass burning organic aerosol (BBOA) particles were collected onto Teflon …

Go to article

Dominant Negative Effects By Inactive Spa47 Mutants Inhibit T3ss Function And Shigella Virulence, Jamie L. Burgess, Heather B. Case, R. Alan Burgess, Nicholas E. Dickenson

Chemistry and Biochemistry Faculty Publications

Type three secretion systems (T3SS) are complex nano-machines that evolved to inject bacterial effector proteins directly into the cytoplasm of eukaryotic cells. Many high-priority human pathogens rely on one or more T3SSs to cause disease and evade host immune responses, underscoring the need to better understand the mechanisms through which T3SSs function and their role(s) in supporting pathogen virulence. We recently identified the Shigella protein Spa47 as an oligomerization-activated T3SS ATPase that fuels the T3SS and supports overall Shigella virulence. Here, we provide both in vitro and in vivo characterization of Spa47 oligomerization and activation in the presence and absence …

Go to article

Structural Dynamics Of Inosine Triphosphate Pyrophosphatase (Itpa) Protein And Two Clinically Relevant Mutants: Molecular Dynamics Simulations, Yao Houndonougbo, Bethany Pugh, Kandise Vanwormer, Caitlin April, Nicholas Burgis

Chemistry and Biochemistry Faculty Publications

The inosine triphosphate pyrophosphatase (ITPA) protein is responsible for removing noncanonical purine nucleoside triphosphates from intracellular nucleotide pools. Absence of ITPA results in genomic instability and increased levels of inosine in DNA and RNA. The proline to threonine substitution at position 32 (P32T) affects roughly 15% of the global population and can modulate treatment outcomes for cancer, lupus, and hepatitis C patients. The substitution of arginine with cysteine at position 178 (R178C) is extremely uncommon and has only been reported in a small cohort of early infantile encephalopathy patients suggesting that a functional ITPA protein is required for life in …

Go to article

Life Sciences Commons^™

Full-Text Articles in Life Sciences

Chemistry and Biochemistry Faculty Publications

Aerosol Mass And Optical Properties, Smoke Influence On O3, And High No3 Production Rates In A Western U.S. City Impacted By Wildfires, Vanessa Selimovic, Robert J. Yokelson, Gavin R. Mcmeeking, Sarah Coefield

Chemistry and Biochemistry Faculty Publications

Influence Of Edge Effects On Laser-Induced Surface Displacement Of Opaque Materials By Photothermal Interferometry, G. A. S. Flizikowski, B. Anghinoni, J. H. Rohling, M. P. Belançon, R. S. Mendes, M. L. Baesso, L. C. Malacarne, T. Požar, Stephen E. Bialkowski, N. G. C. Astrath

Chemistry and Biochemistry Faculty Publications

Chemistry and Biochemistry Faculty Publications

Comparison Of Accelerated Solvent Extraction (Ase) And Energized Dispersive Guided Extraction (Edge) For The Analysis Of Pesticides In Leaves, Ashlie D. Kinross, Kimberly J. Hageman, William J. Doucette, Alexandria L. Foster

Chemistry and Biochemistry Faculty Publications

Influence Of Adjuvants On Pesticide Soil-Air Partition Coefficients: Laboratory Measurements And Predicted Effects On Volatilization, Supta Das, Kimberly J. Hageman

Chemistry and Biochemistry Faculty Publications

N3-Ligated Nickel(Ii) Diketonate Complexes: Synthesis, Characterization And Evaluation Of O2 Reactivity, Josiah G. D. Elsberg, Austin Peterson, Amy L. Fuller, Lisa M. Berreau

Chemistry and Biochemistry Faculty Publications

Modeling The Alkaline Hydrolysis Of Diaryl Sulfate Diesters: A Mechanistic Study, Klaudia Szeler, Nicholas H. Williams, Alvan C. Hengge, Shina C. Kamerlin

Chemistry and Biochemistry Faculty Publications

Chemistry and Biochemistry Faculty Publications

Molecular Composition And Photochemical Lifetimes Of Brown Carbon Chromophores In Biomass Burning Organic Aerosol, Lauren T. Fleming, Peng Lin, James M. Roberts, Vanessa Selimovic, Robert Yokelson, Julia Laskin, Alexander Laskin, Sergey A. Nizkorodov

Chemistry and Biochemistry Faculty Publications

Dominant Negative Effects By Inactive Spa47 Mutants Inhibit T3ss Function And Shigella Virulence, Jamie L. Burgess, Heather B. Case, R. Alan Burgess, Nicholas E. Dickenson

Chemistry and Biochemistry Faculty Publications

Structural Dynamics Of Inosine Triphosphate Pyrophosphatase (Itpa) Protein And Two Clinically Relevant Mutants: Molecular Dynamics Simulations, Yao Houndonougbo, Bethany Pugh, Kandise Vanwormer, Caitlin April, Nicholas Burgis

Chemistry and Biochemistry Faculty Publications