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Articles 91 - 120 of 264

Full-Text Articles in Chemistry

The Investigation Of Lactoferrin Nitration: Quantification, Function, And Inhibition, Amani Yahya Alhalwani Jan 2018

The Investigation Of Lactoferrin Nitration: Quantification, Function, And Inhibition, Amani Yahya Alhalwani

Electronic Theses and Dissertations

Lactoferrin (LF) is an iron-binding glycoprotein of molecular mass ca. 80 kDa that is predominantly found in mammalian body fluids. Lactoferrin is a multifunctional protein that has a wide range of properties such as antibacterial, antiviral, anti-inflammatory, and anti-allergic functions. Tyrosine residues in the protein play a part in many lactoferrin functions. Protein tyrosine nitration modification represents an oxidative and nitrosative stress process which can be caused by the exposure of proteins to oxidants from air pollution or disease. Understanding the way nitrated lactoferrin interacts with the biochemical environment of the body is thus important to the broader goal of …


Revisit Lynwood, Ca: On-Road Remote Sensing Of Automobile Emissions In The Lynwood, Ca: 2018, Gary A. Bishop Jan 2018

Revisit Lynwood, Ca: On-Road Remote Sensing Of Automobile Emissions In The Lynwood, Ca: 2018, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Heavy And Medium-Duty Trucks At The Peralta Weigh Station In The South Coast Air Basin: Spring 2017, Molly J. Haugen, Gary A. Bishop Jan 2018

On-Road Remote Sensing Of Heavy And Medium-Duty Trucks At The Peralta Weigh Station In The South Coast Air Basin: Spring 2017, Molly J. Haugen, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Winter 2017, Gary A. Bishop, Molly J. Haugen Jan 2018

On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Winter 2017, Gary A. Bishop, Molly J. Haugen

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Tulsa Area: Fall 2017, Gary A. Bishop Jan 2018

On-Road Remote Sensing Of Automobile Emissions In The Tulsa Area: Fall 2017, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.


Investigate The Durability Of Diesel Engine Emission Controls, Gary A. Bishop, Molly J. Haugen Jan 2018

Investigate The Durability Of Diesel Engine Emission Controls, Gary A. Bishop, Molly J. Haugen

Fuel Efficiency Automobile Test Publications

No abstract provided.


Evaluation Of Emissions Benefits Of Federal Reformulated Gasoline Versus Conventional Gasoline, Gary A. Bishop, S. Kent Hoekman, Amber Broch Jan 2018

Evaluation Of Emissions Benefits Of Federal Reformulated Gasoline Versus Conventional Gasoline, Gary A. Bishop, S. Kent Hoekman, Amber Broch

Fuel Efficiency Automobile Test Publications

No abstract provided.


The Story Of Ever Diminishing Vehicle Tailpipe Emissions As Observed In The Chicago, Il Area, Gary A. Bishop, Molly J. Haugen Jan 2018

The Story Of Ever Diminishing Vehicle Tailpipe Emissions As Observed In The Chicago, Il Area, Gary A. Bishop, Molly J. Haugen

Fuel Efficiency Automobile Test Publications

The University of Denver has collected on-road fuel specific vehicle emissions measurements in the Chicago area since 1989. This nearly 30 year record illustrates the large reductions in light-duty vehicle tailpipe emissions and the remarkable improvements in emissions control durability to maintain low emissions over increasing periods of time. Since 1989 fuel specific carbon monoxide (CO) emissions have been reduced by an order of magnitude and hydrocarbon (HC) emissions by more than a factor of 20. Nitric oxide (NO) emissions have only been collected since 1997 but have seen reductions of 79%. This has increased the skewness of the emissions …


Long-Term Fuel-Specific Nox And Particle Emission Trends For In-Use Heavy-Duty Vehicles In California, Molly J. Haugen, Gary A. Bishop Jan 2018

Long-Term Fuel-Specific Nox And Particle Emission Trends For In-Use Heavy-Duty Vehicles In California, Molly J. Haugen, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

Two California heavy-duty fleets have been measured in 2013, 2015 and 2017 using the On-road Heavy-duty Measurement System. The Port of Los Angeles drayage fleet has increased in age by 3.3 model years (4.2 to 7.5 years old) since 2013, with little fleet turnover. Large increases in fuel specific particle emissions (PM) observed in 2015 were reversed in 2017, returning to near 2013 levels, suggesting repairs and or removal of high emitting vehicles. Fuel specific oxides of nitrogen (NOx) emissions of this fleet have increased and NOx after-treatment systems do not appear to perform ideally in this …


Evaluation Of Heavy- And Medium-Duty On-Road Vehicle Emissions In California's South Coast Air Basin, Molly J. Haugen, Gary A. Bishop, Arvind Thiruvengadam, Daniel K. Carder Jan 2018

Evaluation Of Heavy- And Medium-Duty On-Road Vehicle Emissions In California's South Coast Air Basin, Molly J. Haugen, Gary A. Bishop, Arvind Thiruvengadam, Daniel K. Carder

Fuel Efficiency Automobile Test Publications

Emission measurements were collected from heavy-duty (HDVs) and medium-duty vehicles (MDVs) at the Peralta weigh station long-term measurement site near Anaheim, CA in 2017. Two Fuel Efficiency Automobile Test units sampled elevated and ground-level exhaust vehicles totaling 2,315 measurements. HDVs (1844 measurements) exhibited historical reductions in fuel specific oxides of nitrogen (NOx) from the 2008 measurements (55%) with increased use of exhaust gas recirculation and selective catalytic reduction systems. However, as these technologies have aged, the in-use benefits have declined. Infrared %opacity measurements of tailpipe soot decreased 14% since 2012 with increased diesel particulate filter (DPF) use, DPF …


Improved Characterization And Analysis Strategies For Uv-Lif Bioaerosol Instrumentation: Lab And Field Application, Nicole Justine Savage Jan 2017

Improved Characterization And Analysis Strategies For Uv-Lif Bioaerosol Instrumentation: Lab And Field Application, Nicole Justine Savage

Electronic Theses and Dissertations

Atmospheric particles of biological origin, also referred to as bioaerosols or primary biological aerosol particles (PBAP), are important to various human health and environmental systems. There has been a recent steep increase in the frequency of published studies utilizing commercial instrumentation based on ultraviolet laser/light-induced fluorescence (UV-LIF), such as the WIBS (wideband integrated bioaerosol sensor), for bioaerosol detection both outdoors and in the built environment. Significant work over several decades supported the development of these technologies, but efforts to systematically characterize the operation of new commercial sensors has remained lacking. Specifically, there are gaps in the understanding of how different …


Quantification Of Airborne Fungal Spores Comparing Molecular Tracers Via Ion Chromatography And Uv-Lif Methods, Marie Ila Gosselin Jan 2017

Quantification Of Airborne Fungal Spores Comparing Molecular Tracers Via Ion Chromatography And Uv-Lif Methods, Marie Ila Gosselin

Electronic Theses and Dissertations

Fungal spores represent an understudied subcategory of bioaerosols that can impact human health as pathogenic and allergenic particles. Fungal spores also have been shown to act as effective ice nuclei and giant cloud condensation nuclei in some cases. This has implications on the hydrological cycle on local and regional scales by impacting the formation and evolution of clouds and precipitation. The quantification of fungal spores has been limited in the past due to methods that were costly and that suffered from poor time resolution. The most commonly applied methods for airborne fungal spore analysis have traditionally included microscopy and culturing, …


Mechanistic Insights Into The Radical S-Adenosyl L-Methionine Enzyme Mftc, Bulat Khaliullin Jan 2017

Mechanistic Insights Into The Radical S-Adenosyl L-Methionine Enzyme Mftc, Bulat Khaliullin

Electronic Theses and Dissertations

Mycofactocin is a putative peptide-derived redox cofactor in Mycobacterium family. Its putative biosynthetic pathway is encoded by the operon mftABCDEF. The initial step of this pathway is a posttranslational modification of a peptide precursor MftA, which is catalyzed by MftC enzyme. This modification only occurs in the presence of chaperone MftB. Here, we demonstrate that MftC is a radical S-adenosyl L-methionine (SAM) enzyme and we examine its catalytic mechanism. We show that the modification of MftA requires two equivalents of SAM and is implemented in two steps: (i) the decarboxylation of a C-terminal tyrosine, resulting in formation of an …


Sequential Growth Of Molecular Complexity Via Alternating Ground State And Photochemical Reactions, Haibo Li Jan 2017

Sequential Growth Of Molecular Complexity Via Alternating Ground State And Photochemical Reactions, Haibo Li

Electronic Theses and Dissertations

A new strategy of increasing molecular complexity by post photochemical oxidation followed by secondary intramolecular photochemical reaction is developed. It is based on the mild oxidation of photochemical generated alcohol by primary intramolecular cycloaddition of aromatic o-aminoaldehydes and a secondary intramolecular cycloaddition of aromatic o-aminoketone. Both cycloadditions are triggered via excited-state intramolecular proton transfer (ESIPT). Additionally, an efficient continuous reaction of photocatalyzed 2-nitrobenzyl alcohol intramolecular reduction and aryl nitroso Diels-Alder (NDA) reaction was discovered.


Repeat Fuel Specific Emission Measurements On Two California Heavy-Duty Truck Fleets, Molly J. Haugen, Gary A. Bishop Jan 2017

Repeat Fuel Specific Emission Measurements On Two California Heavy-Duty Truck Fleets, Molly J. Haugen, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

The University of Denver repeated its 2013 fuel specific gaseous and particle emission measurements on two California heavy-duty vehicle fleets. In 2015 1,457 measurements at the Port of Los Angeles and 694 measurements at the Cottonwood weigh station in northern California were collected. The Port fleet changed little since 2013, increasing the average age (+1.8 years), accompanied by an increase in particle mass (PM) by +266% (0.03 ± 0.01 to 0.11 ± 0.01 gPM/kg of fuel) and black carbon (BC) by +300% (0.02 ± 0.003 to 0.08 ± 0.01 gBC/kg of fuel). Particle number (PN) also increased (1.5 x 10 …


On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Fall 2016, Gary A. Bishop, Molly J. Haugen Jan 2017

On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Fall 2016, Gary A. Bishop, Molly J. Haugen

Fuel Efficiency Automobile Test Publications

No abstract provided.


United States Light And Heavy -Duty Fuel Specific On -Road No And No X Emission Factor Trends And Their Importance In Inventory Calculations (Presentation), Gary A. Bishop Jan 2017

United States Light And Heavy -Duty Fuel Specific On -Road No And No X Emission Factor Trends And Their Importance In Inventory Calculations (Presentation), Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.


Relaxation Of Metals And Their Impact On Nitroxides, Priyanka Aggarwal Jan 2016

Relaxation Of Metals And Their Impact On Nitroxides, Priyanka Aggarwal

Electronic Theses and Dissertations

Pulsed and continuous wave electron spin resonance were used to characterize the relaxation rates of selected paramagnetic metals at 5 to 15 K or 80 K, measure the impact of these rapidly relaxing metals on the relaxation rates of nitroxide radicals in glassy mixtures and in discrete complexes, and characterize novel iron-sulfur proteins.

Spin echoes were observed at 5 to 7 K in 1:1 water:glycerol for Er(diethylenetriamine pentaacetic acid)2- (Er(DTPA)2-), Co(DTPA)3- and aquo Co2+ with relaxation times that are strongly temperature dependent. Deep proton modulation was present on spin echo decays (Ch. 3). For Gd …


Quinolines: Novel Synthesis And Derivatives Of Heterocyclic Bioactive Agents, Ginelle A. Ramann Jan 2016

Quinolines: Novel Synthesis And Derivatives Of Heterocyclic Bioactive Agents, Ginelle A. Ramann

Electronic Theses and Dissertations

Tuberculosis is a pulmonary disease that has ravaged the world throughout history. Even today, many developed and developing countries are experiencing this plight, made worse by the scourge of antibiotic-resistant bacteria.

Mycobacterium tuberculosis's class II fructose-1,6-bisphosphate aldolase presents an interesting target in the design of new therapies against this disease. Previous attempts to construct an inhibitor to this enzyme fell short due to poor selectivity or poor cellular uptake. However a new class of noncompetitive inhibitor based on 8-hydoxyquinoline-2-carboxylic acid presents a fresh approach. Preliminary studies indicate various modifications to this scaffold could be beneficial to its inhibitory efficacy.

Modifications …


Development Of Palladium Catalyzed Alkene Difunctionalization On Vinyl-Quinoline Type Substrate And Isolation Of Pd-Alkyl Intermediate, Lusha Xu Jan 2016

Development Of Palladium Catalyzed Alkene Difunctionalization On Vinyl-Quinoline Type Substrate And Isolation Of Pd-Alkyl Intermediate, Lusha Xu

Electronic Theses and Dissertations

The synthesis of quinoline derivatives is a continuing issue facing organic chemists in both academia and industry. To address this problem, palladium-catalyzed alkene difunctionalization was developed to be a powerful and straightforward strategy of synthetic transformations for adding diversity to organic molecules. In this thesis, Pd-catalyzed olefin difunctionalization reactions of vinyl-quinoline type substrate via generating Pd-alkyl intermediates were mainly described. The reactions described herein are pursuing three significant goals: 1) to isolate and recrystallize Pd-alkyl complexes; 2) to achieve oxidation reactions on Pd-alkyl intermediate; and 3) to investigate stereochemistry of nucleopalladation step on vinyl-quinoline starting materials.


Photoassisted Generation Of Complex N, O, S Polyheterocycles, Weston James Umstead Jan 2016

Photoassisted Generation Of Complex N, O, S Polyheterocycles, Weston James Umstead

Electronic Theses and Dissertations

This research set out to continue the exploration and diversification of excited state o-azaxylylene cycloadditions, utilizing both pre-photochemical and post-photochemical modifications.

Pre-photochemical modifications came through the addition of heteroatoms, namely nitrogen and oxygen, to the tether that links the unsaturated photopendant to the photogenerated o-azaxylylene. Photochemistry resulted in the formation of new, interesting N, O, S polyheterocycles.

Post-photochemical modifications took place through several different cycloaddition reactions, including a [4+2] hetero-Diels Alder reaction, a [4+2] Povarov cyclization, a [3+2] nitrile oxide addition, and a [3+2] nitrone cyclization. These reactions were applied first to a model system, and then to …


On-Road Remote Sensing Of Automobile Emissions In The Tulsa Area: Fall 2015, Gary A. Bishop, Donald H. Stedman Jan 2016

On-Road Remote Sensing Of Automobile Emissions In The Tulsa Area: Fall 2015, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Measuring Real-World Emissions From The On-Road Passenger Fleet, Gary A. Bishop, Donald H. Stedman Jan 2016

Measuring Real-World Emissions From The On-Road Passenger Fleet, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Donald H. Stedman 50 Years Of Air Quality Instrument Inventions And Measurements (Presentation), Gary A. Bishop, Donald H. Stedman Jan 2016

Donald H. Stedman 50 Years Of Air Quality Instrument Inventions And Measurements (Presentation), Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


High-Mileage Light-Duty Fleet Vehicle Emissions: Their Potentially Overlooked Importance, Gary A. Bishop, Donald H. Stedman, Daniel A. Burgard, Oscar Atkinson Jan 2016

High-Mileage Light-Duty Fleet Vehicle Emissions: Their Potentially Overlooked Importance, Gary A. Bishop, Donald H. Stedman, Daniel A. Burgard, Oscar Atkinson

Fuel Efficiency Automobile Test Publications

No abstract provided.


Rapid Scan Electron Paramagnetic Resonance (Epr) And Digital Epr Development, Zhelin Yu Jan 2015

Rapid Scan Electron Paramagnetic Resonance (Epr) And Digital Epr Development, Zhelin Yu

Electronic Theses and Dissertations

Rapid scan electron paramagnetic resonance (EPR) was developed in the Eaton laboratory at the University of Denver. Applications of rapid scan to wider spectra, such as for immobilized nitroxides, spin-labeled proteins, irradiated tooth and fingernail samples were demonstrated in this dissertation. The scan width has been increased from 55 G to 160 G. The signal to noise (S/N) improvement for slowly tumbling spin-labeled protein samples that is provided by rapid scan EPR will be highly advantageous for biophysical studies. With substantial improvement in S/N by rapid scan, the dose estimation for irradiated tooth enamels became more reliable than …


Measurement Of Particulate Transition Metals And Atmospheric Processing Of Iron, Benton T. Cartledge Jan 2015

Measurement Of Particulate Transition Metals And Atmospheric Processing Of Iron, Benton T. Cartledge

Electronic Theses and Dissertations

The work presented herein details the measurement of particle-bound metals in environmental samples with specific interests in iron (Fe) in atmospheric particulate matter. Metals were measured in ambient PM2.5 to study the effects and contributions of a light rail system on the concentrations of metals in atmospheric particles. Particulate matter samples were collected on board trains, near the tracks, and at an urban background location in Denver, CO. Metals were found to be enriched in particles collected on board the trains more so than at the other locations. Fe speciation was also measured in the soluble fraction of the …


Real ‐ World Vehicle Emissions Measurements (Presentation), Gary A. Bishop Jan 2015

Real ‐ World Vehicle Emissions Measurements (Presentation), Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.


Fluorescent Biological Aerosol Particles In Coastal Canada And The Link To Atmospheric Ice Nuclei, Jixiao Li Jan 2015

Fluorescent Biological Aerosol Particles In Coastal Canada And The Link To Atmospheric Ice Nuclei, Jixiao Li

Electronic Theses and Dissertations

Bioaerosols are a subgroup of atmospheric aerosols and are often linked to the spread of human, animal and plant diseases. Bioaerosols also may play an indirect effect on environmental processes, including the formation of precipitation and alteration of the global climate through their role as nuclei for cloud droplet formation. Several types of biological organisms (e.g., fungi and bacteria) have been shown to be effective ice nuclei (IN) and cloud condensation nuclei (CCN).

During 21 days in August 2013 we participated in a collaborative international campaign at a rural, coastal site near the village of Ucluelet on the west coast …


New Methods For Measuring Transient Interactions Between Proteins And Curved Membranes, Philip P. Cheney Jan 2015

New Methods For Measuring Transient Interactions Between Proteins And Curved Membranes, Philip P. Cheney

Electronic Theses and Dissertations

Variations in the physical deformation of the plasma membrane play a significant role in the sorting and behavior of the proteins that occupy it. Determining the interplay between membrane curvature and protein behavior required the development and thorough characterization of a model plasma membrane with well defined and localized regions of curvature. This model system consists of a fluid lipid bilayer that is supported by a dye-loaded polystyrene nanoparticle patterned glass substrate. As the physical deformation of the supported lipid bilayer is essential to our understanding of the behavior of the protein occupying the bilayer, extensive characterization of the structure …