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Articles 1 - 15 of 15
Full-Text Articles in Chemistry
Emissions Of Formaldehyde, Acetic Acid, Methanol, And Other Trace Gases From Biomass Fires In North Carolina Measured By Airborne Fourier Transform Infrared Spectroscopy, Robert J. Yokelson, Jon G. Goode, Darold E. Ward, Ronald A. Susott, Ronald E. Babbitt, D. D. Wade, Issac T. Bertschi, David W. T. Griffith, Wei Min Hao
Emissions Of Formaldehyde, Acetic Acid, Methanol, And Other Trace Gases From Biomass Fires In North Carolina Measured By Airborne Fourier Transform Infrared Spectroscopy, Robert J. Yokelson, Jon G. Goode, Darold E. Ward, Ronald A. Susott, Ronald E. Babbitt, D. D. Wade, Issac T. Bertschi, David W. T. Griffith, Wei Min Hao
Chemistry and Biochemistry Faculty Publications
Biomass burning is an important source of many trace gases in the global troposphere. We have constructed an airborne trace gas measurement system consisting of a Fourier transform infrared spectrometer (FTIR) coupled to a “flow-through” multipass cell (AFTIR) and installed it on a U.S. Department of Agriculture Forest Service King Air B-90. The first measurements with the new system were conducted in North Carolina during April 1997 on large, isolated biomass fire plumes. Simultaneous measurements included Global Positioning System (GPS); airborne sonde; particle light scattering, CO, and CO2; and integrated filter and canister samples. AFTIR spectra acquired within …
Trace Gas Emissions From Laboratory Biomass Fires Measured By Open-Path Fourier Transform Infrared Spectroscopy: Fires In Grass And Surface Fuels, Jon G. Goode, Robert J. Yokelson, Ronald A. Susott, Darold E. Ward
Trace Gas Emissions From Laboratory Biomass Fires Measured By Open-Path Fourier Transform Infrared Spectroscopy: Fires In Grass And Surface Fuels, Jon G. Goode, Robert J. Yokelson, Ronald A. Susott, Darold E. Ward
Chemistry and Biochemistry Faculty Publications
The trace gas emissions from six biomass fires, including three grass fires, were measured using a Fourier transform infrared (FTIR) spectrometer coupled to an open-path, multipass cell (OP-FTIR). The quantified emissions consisted of carbon dioxide, nitric oxide, water vapor, carbon monoxide, methane, ammonia, ethylene, acetylene, isobutene, methanol, acetic acid, formic acid, formaldehyde, and hydroxyacetaldehyde. By including grass fires in this study we have now measured smoke composition from fires in each major vegetation class. The emission ratios of the oxygenated compounds, formaldehyde, methanol, and acetic acid, were 1–2% of CO in the grass fires, similar to our other laboratory and …
Micromagnetics Simulation Of Nanoshaped Iron Elements: Comparison With Experiment, Ngocnga Dao, S. R. Homer, Scott L. Whittenburg
Micromagnetics Simulation Of Nanoshaped Iron Elements: Comparison With Experiment, Ngocnga Dao, S. R. Homer, Scott L. Whittenburg
Chemistry and Biochemistry Faculty Publications
A micromagnetics simulation has been conducted on nanostructured magnetic elements of iron in order to investigate the effect of the shape of the element on magnetic properties, such as domain formation and hysteresis loops. These results are compared with recent experimental studies. The results display an impressive agreement with both the experimentally observed magnetic domains in individual particles as well as the shape of the hysteresis loops. The simulation results then explain features in the hysteresis loops in terms of vortice formation and motion.
Induced Changes In Solvent Structure By Phospholipid Monolayer Formation At A Liquid–Liquid Interface, R. A. Walker, D. E. Gragson, G. L. Richmond
Induced Changes In Solvent Structure By Phospholipid Monolayer Formation At A Liquid–Liquid Interface, R. A. Walker, D. E. Gragson, G. L. Richmond
Chemistry and Biochemistry
Vibrational sum frequency spectroscopy has been used in conjunction with dynamic surface tension measurements to study formation of a 1,2-dilauroyl-sn-phosphatidylcholine (DLPC) monolayer at a water–carbon tetrachloride interface. Surface tension measurements show that an aqueous solution of liquid crystalline phosphocholine vesicles (4.5 μM DLPC) requires several hours to form a tightly packed, fully equilibrated monolayer of DLPC monomers. Vibrational spectra of the interfacial region at different stages in the monolayer formation process indicate that the solvent structure undergoes dramatic re-organization as the monolayer forms. Initial adsorption of DLPC monomers severely disrupts the interfacial hydrogen bonding. Intensity in the OH …
The Mean Spherical Approximation For A Dipolar Yukawa Fluid, Douglas Henderson, Dezso Boda, Istvan Szalai, Kwong-Yu Chan
The Mean Spherical Approximation For A Dipolar Yukawa Fluid, Douglas Henderson, Dezso Boda, Istvan Szalai, Kwong-Yu Chan
Faculty Publications
The dipolar hard sphere fluid (DHSF) is a useful model of a polar fluid. However, the DHSF lacks a vapor–liquid transition due to the formation of chain-like structures. Such chains are not characteristic of real polar fluids. A more realistic model of a polar fluid is obtained by adding a Lennard–Jones potential to the intermolecular potential. Very similar results are obtained by adding a Yukawa potential, instead of the Lennard–Jones potential. We call this fluid the dipolar Yukawa fluid (DYF). We show that an analytical solution of the mean spherical approximation (MSA) can be obtained for the DYF. Thus, the …
Reductive Dehydroxy Coupling Of 2-(Hydroxymethyl)Indenes To Prepare Ethano-Bridged Bis(2-Indenyl) Ansa-Titanocenes, Hasan Palandoken, Justin K. Wyatt, Shawn R. Hitchcock, Marilyn M. Olmstead, Michael H. Nantz
Reductive Dehydroxy Coupling Of 2-(Hydroxymethyl)Indenes To Prepare Ethano-Bridged Bis(2-Indenyl) Ansa-Titanocenes, Hasan Palandoken, Justin K. Wyatt, Shawn R. Hitchcock, Marilyn M. Olmstead, Michael H. Nantz
Chemistry and Biochemistry
New examples of ansa-titanocenes derived from 1,2-bis(2-indenyl)ethane have been prepared. The titanium-mediated reductive coupling of 2-(hydroxymethyl)indenes provided a convenient method for substrate dimerization. Alkyl substitution of the indene ring at C(3) improved the regioselectivity of the reductive coupling to provide the ethylene bis(2-indenyl)ansa-ligands in 29–62% yield.
Monte Carlo Study Of The Capacitance Of The Double Layer In A Model Molten Salt, Douglas Henderson, Dezso Boda, Kwong-Yu Chan
Monte Carlo Study Of The Capacitance Of The Double Layer In A Model Molten Salt, Douglas Henderson, Dezso Boda, Kwong-Yu Chan
Faculty Publications
Monte Carlo simulations are reported for charged hard spheres at high density near a charged wall. This system is a simple model for a molten salt double layer. Unfortunately, the reduced temperatures that correspond to experiment are very small. This results in a large Boltzmann factor. As a result, we are unable to obtain meaningful results for such low values and report results only for moderately low values of the reduced temperature. Even so, our results should be a useful benchmark. Further, we are able to give a qualitative answer to an interesting question. We find that at low temperatures …
Relationship Between Udp-Glucose 4-Epimerase Activity And Oligoglucose Glycoforms In Two Strains Of Neisseria Meningitidis, F K. Lee, B W. Gibson, William Melaugh, A Zaleski, M A. Apicella
Relationship Between Udp-Glucose 4-Epimerase Activity And Oligoglucose Glycoforms In Two Strains Of Neisseria Meningitidis, F K. Lee, B W. Gibson, William Melaugh, A Zaleski, M A. Apicella
Chemistry Faculty Publications
Sodium dodecyl sulfate-polyacrylamide gel analysis of lipooligosaccharide (LOS) from Neisseria meningitidis has demonstrated considerable microheterogeneity in the variable region of LOS due to the presence of novel glycoforms. As a step toward understanding the basis for the expression of these novel glycoforms, we have examined the LOS structures and UDP-glucose 4-epimerase (epimerase) activity levels in two strains (NMB and MA-1) and their respective galE mutants. Strain NMB was found to have low epimerase activity and to contain multiple glycoforms, some of which appear to contain only glucose sugars. The galE mutant had only the oligoglucose glycoforms. Strain MA-1 had higher …
Iron-Induced Oxidative Stress In Erythrocyte Membranes Of Non-Insulin-Dependent Diabetic Nigerians, Gbolahan W. Okunade, Odutayo O. Odunuge, Olufunso O. Olorunsogo
Iron-Induced Oxidative Stress In Erythrocyte Membranes Of Non-Insulin-Dependent Diabetic Nigerians, Gbolahan W. Okunade, Odutayo O. Odunuge, Olufunso O. Olorunsogo
Faculty Publications
The presence of higher level of endogenous free radical reaction products in the erythrocyte ghost membrane (EGM) of Non-insulin-dependent diabetes mellitus (NIDDM) subjects compared with that of normal healthy controls has been demonstrated. The EGMs of NIDDM subjects were also shown to be more susceptible to exogenously generated oxidative stress than those of normal healthy individuals. The decreased level of reactive thiol groups in the EGM of NIDDM individuals supported this observation. We propose that the presence of significant levels of non-heme iron in the EGM of NIDDM subjects is an indication of the potential for iron-catalysed production of hydroxy …
Reversal Of Sodium Arsenite Inhibition Of Rat Liver Microsomal Ca2+ Pumping Atpase By Vitamin C, Odutayo O. Odunuge, Gbolahan W. Okunade, Olufunso O. Olorunsogo
Reversal Of Sodium Arsenite Inhibition Of Rat Liver Microsomal Ca2+ Pumping Atpase By Vitamin C, Odutayo O. Odunuge, Gbolahan W. Okunade, Olufunso O. Olorunsogo
Faculty Publications
Sodium arsenite (NaAsO2), at 10% of its median lethal dose, was administered to rats with and without vitamin C pretreatment. Liver microsomal fraction was isolated and the activity of Ca2+-ATPase was assayed. Sodium arsenite was found to inhibit the activity of the liver microsomal Ca2+-ATPase to 50% to that of control rats. The specific activity of the enzyme in rats administered sodium arsenite with vitamin C pretreatment was not significantly different from that of control rats.
Affinity Chromatography: A Review Of Clinical Applications, David S. Hage
Affinity Chromatography: A Review Of Clinical Applications, David S. Hage
David Hage Publications
Affinity chromatography is a type of liquid chromatography that makes use of biological-like interactions for the separation and specific analysis of sample components. This review describes the basic principles of affinity chromatography and examines its use in the testing of clinical samples, with an emphasis on HPLCbased methods. Some traditional applications of this approach include the use of boronate, lectin, protein A or protein G, and immunoaffinity supports for the direct quantification of solutes. Newer techniques that use antibody-based columns for on- or off-line sample extraction are examined in detail, as are methods that use affinity chromatography in combination with …
A Biogeochemical Comparison Of Fossil (Carboniferous) And Modern Crustose Red Algae, Michael A. Kruge, John E. Utgaard, William Ferry
A Biogeochemical Comparison Of Fossil (Carboniferous) And Modern Crustose Red Algae, Michael A. Kruge, John E. Utgaard, William Ferry
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
The nature of the contribution of the various types of algae to sedimentary organic matter continues to be a topic of research interest. Crustose red algae have however received less attention than other types. The fossil calcareous red algae (Rhodophyta) analyzed in this study are two relatively unrecrystallized specimens of Parachaetetes (Family Solenoporacea) from the lower part of the Ste. Genevieve Formation (Carboniferous, Visean) in Union County, Illinois, USA. They occurred in the patch reef phase of a small carbonate mudmound-patchreef. The three modern specimens (collected and identified by F. Collier) are the crustose algae Lithothamnion, Clathromorphum and Phymatolithon …
Cyclopropane Fatty Acid Expression In Plants, Katherine M. Schmid
Cyclopropane Fatty Acid Expression In Plants, Katherine M. Schmid
Scholarship and Professional Work - LAS
Pants [sic] are transformed with a bacterial cyclopropane fatty acid synthase gene to produce lipids containing cyclopropane fatty acids. Using this technology dihydrosterculate is produced in oilseed crops such as rape.
Some Aspects Of The Adsorption Of A Lennard-Jones Gas On A Rough Surface, Douglas Henderson, Pawel Bryk, Stefan Sokolowski
Some Aspects Of The Adsorption Of A Lennard-Jones Gas On A Rough Surface, Douglas Henderson, Pawel Bryk, Stefan Sokolowski
Faculty Publications
We study the adsorption, including wetting, of a Lennard-Jones gas on a rough surface consisting of rough layer on a smooth substrate with which the gas interacts via a 9-3 potential. The rough layer is two molecular diameters thick and consists of a disordered quenched matrix of hard spheres. As well as interacting with the other matrix spheres by the hard-sphere potential, the matrix molecules interact with the gas molecules by the hard-sphere potential. Hence, on average, the degree to which the gas molecules can approach the substrate depends only on the density of the matrix layer. The density of …
Two-Photon Excitation Of Rhenium Metal-Ligand Complexes, Joseph R. Lakowicz, Felix N. Castellano, Ignacy Gryczynski, Zygmunt Gryczynski, Jonathan D. Dattelbaum
Two-Photon Excitation Of Rhenium Metal-Ligand Complexes, Joseph R. Lakowicz, Felix N. Castellano, Ignacy Gryczynski, Zygmunt Gryczynski, Jonathan D. Dattelbaum
Chemistry Faculty Publications
We describe the emission spectral properties of two rhenium metal-ligand complexes with one and two-photon excitation, Re(bpy)2(CO)3Cl and [Re(bpy)(CO)3CH3CN]+, where bpy is 2,2’-bipyridyl and CH3CN is acetonitrile. Similar emission spectra and intensity decay times characteristic of the metal-to-ligand charge transfer state were observed for one- and two-photon excitation. The lifetime and quantum yield of the acetonitrile complex are approximately 14-fold higher than that of the chloride complex. Both complexes display high anisotropies near 0.33 in frozen solution with one-photon excitation. Two-photon excitation results in anisotropies about 40% larger, …