Chemistry Commons^™

Trace Gas And Particle Emissions From Fires In Large Diameter And Belowground Biomass Fuels, Isaac T. Bertschi, Robert J. Yokelson, Darold E. Ward, R. E. Babbitt, Ronald A. Susott, Jon G. Goode, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

[1] We adopt a working definition of residual smoldering combustion (RSC) as biomass combustion that produces emissions that are not lofted by strong fire-induced convection. RSC emissions can be produced for up to several weeks after the passage of a flame front and they are mostly unaffected by flames. Fuels prone to RSC include downed logs, duff, and organic soils. Limited observations in the tropics and the boreal forest suggest that RSC is a globally significant source of emissions to the troposphere. This source was previously uncharacterized. We measured the first emission factors (EF) for RSC in a series of …

Review Of The Final Frontier, Michael F. Russo

Faculty Publications

No abstract provided.

Development Of A Systems Engineering Model Of The Chemical Separations Process: Quarterly Progress Report 11/16/02- 2/15/03, Yitung Chen, Randy Clarksean, Darrell Pepper

Separations Campaign (TRP)

Two activities are proposed in this Phase I task: the development of a systems engineering model and the refinement of the Argonne code AMUSE (Argonne Model for Universal Solvent Extraction). The detailed systems engineering model is the start of an integrated approach to the analysis of the materials separations associated with the TRP Program. A second portion of the project is to streamline and improve an integral part of the overall systems model, which is the software package AMUSE. AMUSE analyzes the UREX process and other related solvent extraction processes and defines many of the process streams that are integral …

Examination Of The Role Of The Clamp-Loader And Atp Hydrolysis In The Formation Of The Bacteriophage T4 Polymerase Holoenzyme, Michael A. Trakselis, Anthony J. Berdis, Stephen J. Benkovic

Chemistry Faculty Publications

Transient kinetic analyses further support the role of the clamp-loader in bacteriophage T4 as a catalyst which loads the clamp onto DNA through the sequential hydrolysis of two molecules of ATP before and after addition of DNA. Additional rapid-quench and pulse-chase experiments have documented this stoichiometry. The events of ATP hydrolysis have been related to the opening/closing of the clamp protein through fluorescence resonance energy transfer (FRET). In the absence of a hydrolysable form of ATP, the distance across the subunit interface of the clamp does not increase as measured by intramolecular FRET, suggesting gp45 cannot be loaded onto DNA. …

Trace Gas Emissions From The Production And Use Of Domestic Biofuels In Zambia Measured By Open-Path Fourier Transform Infrared Spectroscopy, Isaac T. Bertschi, Robert J. Yokelson, Darold E. Ward, Ted J. Christian, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

[1] Domestic biomass fuels (biofuels) were recently estimated to be the second largest source of carbon emissions from global biomass burning. Wood and charcoal provide approximately 90% and 10% of domestic energy in tropical Africa. In September 2000, we used open-path Fourier transform infrared (OP-FTIR) spectroscopy to quantify 18 of the most abundant trace gases emitted by wood and charcoal cooking fires and an earthen charcoal-making kiln in Zambia. These are the first in situ measurements of an extensive suite of trace gases emitted by tropical biofuel burning. We report emission ratios (ER) and emission factors (EF) for (in order …

Semiclassical Dynamics With Quantum Trajectories: Formulation And Comparison With The Semiclassical Initial Value Representation Propagator, Sophya Garashchuk, Vitaly A. Rassolov

Faculty Publications

We present a time-dependent semiclassical method based on quantum trajectories. Quantum-mechanical effects are described via the quantum potential computed from the wave function density approximated as a linear combination of Gaussian fitting functions. The number of the fitting functions determines the accuracy of the approximate quantum potential (AQP). One Gaussian fit reproduces time-evolution of a Gaussian wave packet in a parabolic potential. The limit of the large number of fitting Gaussians and trajectories gives the full quantum-mechanical result. The method is systematically improvable from classical to fully quantum. The fitting procedure is implemented as a gradient minimization. We also compare …

Efficient Incorporation Of Coa, Nad And Fad Into Rna By In Vitro Transcription, Faqing Huang

Faculty Publications

Protein enzymes frequently recruit small molecule coenzymes to perform a variety of biochemical reactions. While the catalytic activities of RNA have been expanding rapidly, a similar strategy for RNA to utilize coenzymes and to increase its functional capabilities has yet to be demonstrated. A general in vitro transcription procedure has been developed to efficiently prepare RNA with coenzymes CoA, NAD and FAD covalently attached to the 5' end. These adenosine-containing coenzymes initiate transcription under the T7 class II promoter by T7 RNA polymerase. In addition to the three coenzymes, other adenosine-containing molecules may be incorporated into the first nucleotide position …

Corrosion Of Steel By Lead Bismuth Eutectic: Quarterly Report November- December 2002 January 2003, John Farley

Transmutation Sciences Materials (TRP)

We continue to get valuable data from sputter depth profiling of steel samples. We meet weekly to discuss progress. We took depth-profiling data on D9 steel that had been exposed to LBE. This the first time we have examined this type of steel. This is important because it will enable us to separate out two effects and determine their effect on corrosion: composition of the steel vs surface preparation.

We started to plan a small experiments using a crucible of heated LBE, with the research program to be conducted at UNLV, on basic aspects of corrosion in this system. The …

Synthesis And Potential Antimetastatic Activity Of Monovalent And Divalent Β-D-Galactopyranosyl-(1→4)-2-Acetamido-2-Deoxy-D-Glucopyranosides, Qin Li, Bin Su, Hui Li, Xiang Bao Meng, Meng Shen Cai, Zhong Jun Li, Rou Li Zhou, Ta Lin Suo

Chemistry Faculty Publications

Anomers of monovalent and divalent β-d-galactopyranosyl-(1→4)-2-acetamido-2-deoxy-d-gluco-pyranosides were synthesized under different glycosylation conditions, and evaluated for in vitro antimetastatic activity. Three compounds showed promising inhibitory effects on cancer cell attachment, spreading, migration, and invasion. Six divalent O-β-d-galactopyranosyl-(1→4)-2-acetamido-2-deoxy-d-glucopyranosides (29–34) were synthesized and their antimetastatic activities were studied.

Calibration Of Ysz Sensors For The Measurement Of Oxygen Concentration In Liquid Pb-Bi Eutectic, Xiaolong Wu, Ramkumar Sivaraman, Ning Li, Wei Hang, T. W. Darling, Yingtao Jiang, Woosoon Yim, Bingmei Fu

Transmutation Sciences Materials (TRP)

Although liquid lead-bismuth eutectic (LBE) is a good candidate for coolant in the subcritical transmutation blanket, it is known to be corrosive to stainless steel, the material of the carrying tubes and containers. Such longterm corrosion problem can be prevented by producing and maintaining a protective oxide layer on the exposed surface of stainless steel. For this purpose, it is required to accurately control the concentration of oxygen dissolved in LBE. Currently, YSZ (Yttria Stabilized Zirconia) oxygen sensors, based on an existing automotive oxygen sensor, with molten bismuth saturated with oxygen as the reference, have been selected for oxygen-concentration measurement. …

Development Of A Systems Engineering Model Of The Chemical Separations Process, Lijian Sun, Haritha Royyuru, Yitung Chen, Randy Clarksean, Darrell Pepper, George Vandegrift, James Laidler

Separations Campaign (TRP)

Project Overview:

• Two Components

– Refine AMUSE Code

– Develop Systems Engineering Model

• Research Objectives

– Develop a framework and environment for a systems engineering analysis of the chemical separations system for the AAA program.

– Establish a baseline systems engineering model from which modifications and improvements can be made.

– Refine the existing AMUSE program that gives a detailed examination of the UREX process, a critical component of the overall separation scheme.

Liquid Chromatography–Mass Spectrometry Method For The Analysis Of The Anti-Cancer Agent Capecitabine And Its Nucleoside Metabolites In Human Plasma, Yan Xu, Jean L. Grem

Chemistry Faculty Publications

A reversed-phase high-performance liquid chromatography method with electrospray ionization and mass spectral detection is described for the determination of capecitabine, 5′-deoxy-5-fluorocytidine and 5′-deoxy-5-fluorouridine in human plasma with 5-chloro-2′-deoxyuridine as the internal standard. An on-line sample clean-up procedure allows dilution of the plasma sample with the initial mobile phase. The linear dynamic range is 0.0500–10.0 μg/ml for capecitabine, and 0.0500–25.0 μg/ml for the metabolites, 5′-deoxy-5-fluorocytidine and 5′-deoxy-5-fluorouridine, respectively. This method has been used to analyze plasma samples from patients receiving capecitabine in combination with oxaliplatin.

Phosphoproteomic Studies Of Smooth Muscle Contraction: Investigation Of Differential Phosphorylation In Relaxed/Contracted Rat Aortic Smooth Muscle Tissue Using Maldi-Tof Ms, Tonya M. Pekar

Theses, Dissertations and Capstones

Many human disorders are associated with the malfunction of smooth muscle tissue, or are related to the capabilities of its proper function—asthma, glaucoma, renal inefficiency, hypertension, and cardiovascular disease. Dysfunctional proteins are frequently implicated as the source of such disorders. As the second highest cause of death in the United States, the epidemic of cardiovascular disease makes the study of smooth muscle of utmost concern.

The capabilities of proteomics and mass spectrometry allow the entire proteome complement of a cell or tissue type to be analyzed at once. This investigation employs such techniques in an effort to better understand the …

Investigations Of Supramolecular And Catalytic Properties Of Ppi Dendrimers, Aaron K. Holley

Theses, Dissertations and Capstones

The research reported in this thesis focused on supramolecular and catalytic properties of poly(propylene imine) (PPI) dendrimers. Analytical techniques used in this research included high resolution NMR spectroscopy, as well as UV-vis and fluorescence spectroscopies and scanning electron microscopy. This investigation showed that: (1) PPI dendrimers interact with diacids to form interlock self-assemblies by electrostatic interactions (with an increase in dendrimer generation, smaller diacids are required to form the most efficient self-assembly); (2) PPI/diacid self-assemblies are able to encapsulate fluorescent dyes within the void spaces of the PPI/diacid moieties; (3) PPI-3 can chelate many types of metal cations, and these …

The Microwave Spectrum, Ab Initio Analysis, And Structure Of The Fluorobenzene–Hydrogen Chloride Complex, M. Eugenia Sanz, Sonia Antolinez, Jose Alonso, Juan Lopez, Robert Kuczkowski, Sean Peebles, Rebecca Peebles, Faith Boman, Elfi Kraka, Dieter Cremer

Faculty Research and Creative Activity

The fluorobenzene–hydrogen chloride π-hydrogen-bonded complex has been studied by high resolution microwave spectroscopy and ab initio calculations. Rotational spectra of the C6H5F–H35Cl, C6H5F–H37Cl, and C6D5F–H35Cl isotopomers were assigned using pulsed molecular beam techniques in a Fourier-transform microwave spectrometer. The spectra are consistent with a structure of the complex in which the HCl is above the fluorobenzene ring near the ring center, similar to the benzene–HCl prototype dimer. An analysis of the inertial data and the chlorine quadrupole coupling tensor results in two mathematically possible locations for the HCl subunit with respect to the fluorobenzene arising from sign ambiguities in interpreting …

The Microwave Spectrum, Ab Initio Analysis, And Structure Of The Fluorobenzene–Hydrogen Chloride Complex, M. Eugenia Sanz, Sonia Antolinez, Jose L. Alonso, Juan C. Lopez, Robert L. Kuczkowski, Sean A. Peebles, Rebecca A. Peebles, Faith C. Boman, Elfi Kraka, Dieter Cremer

Faculty Research and Creative Activity

The fluorobenzene–hydrogen chloride π-hydrogen-bonded complex has been studied by high resolution microwave spectroscopy and ab initio calculations. Rotational spectra of the C6H5F–H35Cl, C6H5F–H37Cl, and C6D5F–H35Cl isotopomers were assigned using pulsed molecular beam techniques in a Fourier-transform microwave spectrometer. The spectra are consistent with a structure of the complex in which the HCl is above the fluorobenzene ring near the ring center, similar to the benzene–HCl prototype dimer. An analysis of the inertial data and the chlorine quadrupole coupling tensor results in two mathematically possible locations for the HCl subunit with respect to the fluorobenzene arising from sign ambiguities in interpreting …

A Solvent-Free Oxidation Of Alcohols In An Organic Laboratory, John J. Esteb, Michael W. Schelle, Anne N. Wilson

Scholarship and Professional Work - LAS

An oxidation experiment for a first-year organic chemistry class is presented. This oxidation utilizes a solid mixture of CuSO4•5H2O and KMnO4 prepared by mortar and pestle. The oxidations take place under solvent-free conditions and near quantitative yields are obtained for the reactions. Thin-layer chromatography is used to monitor the progress of the reaction. This experiment provides for the simple oxidation of a secondary alcohol to a ketone using a relatively nontoxic oxidizing agent under solvent-free conditions.

Reactions Of Boranes And Metallaboranes With Phosphines, Lawrence Barton, Oleg Volkov, Mitsuhiro Hata, Paul Mcquade, Nigam Rath

Chemistry & Biochemistry Faculty Works

This paper reports extensions of the well-established field of phosphine–borane chemistry. Linked clusters, for example, {[(PPh3)2(CO)OsB4H7-3-BH2-PPh2]2 [(Fe(C5H4)2]}, are formed in reactions of rigid backboned bidentate phosphines with {2,2,2-(PPh3)2(CO)-nido-2-OsB5H9]. Reaction of bidentate phosphines with the unsaturated clusters [8,8-PPh3)2-nido-8,7-RhSB9H10] and [9,9-(PPh3)2-nido-9,7,8-RhC2B8 H11] leads to the isolation of novel species such as {1-(PPh3)[1,3-(µ-dppm)]-closo -1,2-RhSB9H8},with a dppm molecule bridging adjacent metal and boron vertices in the cage, [1,1-(ç2-dppe)-3-(ç1-dppm)-closo-1,2-RhSB 9H8], a mixed ligand system, and {9,9-ç2-[(ç2-BH3)PPh2PCH2 PPh2]-nido- 9,7,8-RhC2B8H11} which contains a bidentate dppm BH3 moiety. The formation of bidentate phosphine-linked main group transition-metal moieties such as [BH3PPh2(CH)nPPh2IrCp*Cl2] is also described as is an example of …

Tetratricopeptide Repeat Motif-Mediated Hsc70-Msti1 Interaction Molecular Characterization Of The Critical Contacts For Successful Binding And Specificity*, Odutayo O. Odunuge, Judith A. Hornby, Chrisiane Bies, Richard Zimmermann, David J. Pugh, Gregory L. Blatch

Faculty Publications

Murine stress-inducible protein 1 (mSTI1) is a cochaperone that is homologous with the human Hsp70/ Hsp90-organizing protein (Hop). Guided by Hop structural data and sequence alignment analyses, we have used site-directed mutagenesis, co-precipitation assays, circular dichroism spectroscopy, steady-state fluorescence, and surface plasmon resonance spectroscopy to both qualitatively and quantitatively characterize the contacts necessary for the N-terminal tetratricopeptide repeat domain (TPR1) of mSTI1 to bind to heat shock cognate protein 70 (Hsc70) and to discriminate between Hsc70 and Hsp90. We have shown that substitutions in the first TPR motif of Lys8 or Asn12 did not affect binding of mSTI1 to Hsc70, …

Dendritic Surfactants Show Evidence For Frustrated Intercalation: A New Organoclay Morphology, Erick J. Acosta, Youjun Deng, G. Norman White, Joe B. Dixon, Kevin J. Mcinnes, Scott A. Senseman, Alyx S. Frantzen, Eric E. Simanek

Faculty Publications

Mixing a smectite clay with some dendritic surfactants shows that despite the large size of some of these molecules, a property that frustrates complete intercalation into the gallery of the clay, organoclay materials are obtained. X-ray powder diffraction (XPD) reveals no significant increases in lattice spacing as these surfactants are added. Infrared (IR) spectroscopy and thermal gravimetric analysis (TGA) show that interlayer water is preserved. Consistent with an undisturbed interlayer, the amount of organic material in organoclays derived from frustrated surfactants does not exceed 15% of the cationic exchange capacity (CEC) of the composite. Smaller dendritic surfactants do not display …

Determining Crystal Thickness By Measuring Optical Rotation In Chiral Crystals, Cori Bruce, James Bish, Jamie Walker

The Corinthian

In this experiment, it will be shown that the linear relationship between pathlength and observed rotation can be applied to predict the pathlength based on the observed rotation. It should be noted, however, that the method devised will only work for chiral crystals. When aqueous NaC103 solution evaporates two rotamers will form that will rotate plane-polarized light in equal but opposite directions. Hence, the crystals must be separated to obtain linear correlations in regards to the two rotamers.

Anion Photoelectron Spectroscopy Of Solvated Transition State Precursors, Harry Gomez, Giovanni Meloni, James Madrid, D M. Neumark

Chemistry Faculty Publications

Photoelectron (PE) spectra have been collected for the clustered bihalide anions XHX−∙(M) (X=Br, I) and BrHI−∙(M), where M=H2O, HBr, and HI, in order to probe the effects of strongly solvating species on the PE spectra of transition state precursor anions. The PE spectra of the XHX−∙(H2O) ions show similar vibrational progressions as the spectra of the bare BrHBr− and IHI− anions, indicating that photodetachment of the bare and hydrated ions accesses similar XHX transition state geometries on the X+HX reactionpotential energy surfaces. These results are consistent with electronic structure calculations that predict a double hydrogen-bonded XHX−∙(H2O) structure in which the …

Response To “Comment On ‘Atomization Energies And Enthalpies Of Formation Of The Snbi[Sub N] (N=1–3) Gaseous Molecules By Knudsen Cell Mass Spectrometry’ ” [J. Chem. Phys. 118, 4766 (2003)], Giovanni Meloni, Karl A. Gingerich

Chemistry Faculty Publications

Discusses atomization energies and enthalpies of formation of gaseous molecules of compounds containing tin and bismuth by Knudsen cell mass spectrometry. Procedure followed to evaluate the mass spectrometric equilibrium data regarding these molecules; Statistics of atomization energies and enthalpies calculated; Factors contributing to the necessity of high level of calculations to obtain these figures.

Molecular Dynamics Simulation Of The Order- Disorder Phase Transition In Solid Nano2, Wei-Guo Yin, Chun-Gang Duan, Wai-Ning Mei, Jianjun Liu, Robert W. Smith, John R. Hardy

Physics Faculty Publications

We present molecular dynamics simulations of solid NaNO2 using pair potentials with the rigid-ion model. The crystal potential surface is calculated by using an a priori method which integrates the ab initio calculations with the Gordon-Kim electron gas theory. This approach is carefully examined by using different population analysis methods and comparing the intermolecular interactions resulting from this approach with those from the ab initio Hartree-Fock calculations. Our numerics show that the ferroelectric-paraelectric phase transition in solid NaNO2 is triggered by rotation of the nitrite ions around the crystallographical c axis, in agreement with recent x-ray experiments @Gohda et al., …

Oligothiophenes And Synthesis Thereof, Andrzej Rajca

Department of Chemistry: Faculty Publications

Novel oligothiophenes and intermediates therefor are disclosed together with a process for synthesizing them. The oligothiophenes are in the form of a helix which contains five-membered rings unsaturated heterocycles that are cross-conjugated and annelated into a helix.

Fluorescence Determination Of Tryptophan Side-Chain Accessibility And Dynamics In Triple-Helical Collagen-Like Peptides, K. V. Simon-Lukasik, A. V. Persikov, B. Brodsky, J. A. M. Ramshaw, William Laws, J. B. A. Ross, R. D. Ludescher

Chemistry and Biochemistry Faculty Publications

We report tryptophan fluorescence measurements of emission intensity, iodide quenching, and anisotropy that describe the environment and dynamics at X and Y sites in stable collagen-like peptides of sequence (Gly-X-Y)(n). About 90% of tryptophans at both sites have similar solvent exposed fluorescence properties and a lifetime of 8.5-9 ns. Analysis of anisotropy decays using an associative model indicates that these long lifetime populations undergo rapid depolarizing motion with a 0.5 ns correlation time; however, the extent of fast motion at the Y site is considerably less than the essentially unrestricted motion at the X site. About 10% of tryptophans at …

Constrained Analysis Of Fluorescence Anisotropy Decay: Application To Experimental Protein Dynamics, E. Feinstein, G. Deikus, E. Rusinova, E. L. Rachofsky, J. B. A. Ross, William Laws

Chemistry and Biochemistry Faculty Publications

Hydrodynamic properties as well as structural dynamics of proteins can be investigated by the well-established experimental method of fluorescence anisotropy decay. Successful use of this method depends on determination of the correct kinetic model, the extent of cross-correlation between parameters in the fitting function, and differences between the timescales; of the depolarizing motions and the fluorophore's fluorescence lifetime. We have tested the utility of an independently measured steady-state anisotropy value as a constraint during data analysis to reduce parameter cross correlation and to increase the timescales over which anisotropy decay parameters can be recovered accurately for two calcium-binding proteins. Mutant …

Comparison Between Hydrogen And Dihydrogen Bonds Among H3bnh3, H2bnh2, And Nh3, T. Kar, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Several possible binary complexes among ammonia-borane, aminoborane, and ammonia, via hydrogen and/or dihydrogen bonds, have been investigated to understand the effect of different hybridization. Møller–Plesset second-order perturbation theory with aug-cc-pVDZ basis set was used. The interaction energy is corrected for basis set superposition error, and the Morokuma–Kitaura method was employed to decompose the total interaction energy. Like H₃BNH₃, the sp² hybridized H₂BNH₂ also participates in H- and dihydrogen bond formation. However, such bonds are weaker than their sp³ analogs. The contractions of BN bonds are associated with blueshift in …

On The Existence And Stability Of Liquid Water On The Martian Surface, Justin Thompson

Inquiry: The University of Arkansas Undergraduate Research Journal

Present-day Mars is thought to be a frozen desert on which liquid water is not likely to be found. The prevailing assumption has been that due to average temperatures below 273 K and atmospheric pressures at or below water's triple-point vapor pressure of 6.1 mbar, the existence of liquid water as an equilibrium phase at or near the surface is impossible at the present epoch. However, there is substantial evidence that liquid water has existed in the past and may presently still exist on or directly below the Martian surface. I conducted simulation experiments in the Andromeda planetary environmental chamber …

Self-Aggregates Of Cationic Meso-Tetratolylporphyrins In Aqueous Solutions, Pavel Kubat, Kamil Lang, Kristina Prochazkova, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

Aggregation properties of meso-tetratolylporphyrins bearing cationic substituents of a lipophilic nature such as ammonium, pyridinium, phosphonium, sulfonium, and isothiouronium were studied by UV/vis and resonance light scattering spectroscopy. The exciton point-dipole approximation was used to predict the structural alignment of the porphyrin units within the aggregate. The contribution of various types of aggregates depends on the porphyrin substitution, ionic strength, and temperature of aqueous solution of the porphyrin. In general, the preferred structure of an aggregate formed by temperature-induced aggregation is the J-aggregate exhibiting the characteristically narrow, red-shifted Soret band indicating a parallel "side-by-side" arrangement of the porphyrin units. The …