Some Studies Involving Pyridine N-oxide Reductase (open access)

Some Studies Involving Pyridine N-oxide Reductase

The study herein described involved the detection of pyridine N-oxide reductase activity in cell-free extracts of E. coli 9723, the determination of co-factors necessary for the enzymatic process, a study of the optimum conditions for enzyme catalysis, and a general characterization of the enzyme.
Date: August 1968
Creator: Waters, Samuel Wayne
System: The UNT Digital Library
The Analysis of PCDD and PCDF Emissions from the Cofiring of Densified Refuse Derived Fuel and Coal (open access)

The Analysis of PCDD and PCDF Emissions from the Cofiring of Densified Refuse Derived Fuel and Coal

The United States leads the world in per capita production of Municipal Solid Waste (MSW), generating approximately 200 million tons per year. By 2000 A.D. the US EPA predicts a 20% rise in these numbers. Currently the major strategies of MSW disposal are (i) landfill and (ii) incineration. The amount of landfill space in the US is on a rapid decline. There are -10,000 landfill sites in the country, of which only 65-70% are still in use. The Office of Technology Assessment (OTA) predicts an 80% landfill closure rate in the next 20 years. The development of a viable energy resource from MSW, in the form of densified Refuse Derived Fuel (dRDF), provides solutions to the problems of MSW generation and fossil fuel depletions. Every 2 tons of MSW yields approximately 1 ton of dRDF. Each ton of dRDF has an energy equivalent of more than two barrels of oil. At current production rates the US is "throwing away" over 200,000,000 barrels of oil a year. In order to be considered a truly viable product dRDF must be extensively studied; in terms of it's cost of production, it's combustion properties, and it's potential for environmental pollution. In 1987 a research …
Date: August 1990
Creator: Moore, Paul, 1962-
System: The UNT Digital Library
Synthesis of Certain Aminooxy Compounds (open access)

Synthesis of Certain Aminooxy Compounds

The research described herein is concerned with the synthesis of certain organic compounds which have the amino-oxy grouping and are related in structure to the naturally occurring amines, putrescine, spermidine and spermine.
Date: January 1970
Creator: Lewis, Wassel Andrew
System: The UNT Digital Library
Synthesis and Study of Certain Amino Acids Containing the Pyridine Ring (open access)

Synthesis and Study of Certain Amino Acids Containing the Pyridine Ring

This study reported herein involves the synthesis and determination of certain biological activities of 4,5-dihydroxy-2-pyridinealanine and the synthesis of 3-pyridine-N-methylalanine.
Date: January 1969
Creator: Sanders, Edward Henry
System: The UNT Digital Library
The Ascorbic Acid Metabolism of Fifty College Women in the North Texas State Teachers College (open access)

The Ascorbic Acid Metabolism of Fifty College Women in the North Texas State Teachers College

A study of the ascorbic acid metabolism of a group of fifty college women in the North Texas State Teachers College between the months of April and July, 1943.
Date: 1943
Creator: Harshbarger, Marjorie
System: The UNT Digital Library
Regulation of Pyridine Nucleotide Metabolism in Saccharomyces cerevisiae (open access)

Regulation of Pyridine Nucleotide Metabolism in Saccharomyces cerevisiae

The levels of total nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), and their redox states were determined as the function of growth in S. cerevisiae. Cells growing in a medium containing 0.8% glucose exhibit two phases of exponential growth, utilizing glucose and ethanol, respectively. The NAD pool is 50% reduced during both stages of growth while the NADP pool is 67% reduced in glucose growth and 48% reduced in ethanol growth. The NAD/NADP ratio is constant during growth on glucose and a two-fold increase in the NAD/NADP ratio occurs upon exhaustion of glucose. The increased ratio is maintained during growth on ethanol. This alteration in the regulation of the relative levels of NAD and NADP may be due to a change in the regulation of NAD kinase and/or NADP phosphatase activities. These changes may be related to the redox state of the NADP pool.
Date: May 1976
Creator: Ting, Haung-yu
System: The UNT Digital Library
Selective Lipid Absorption (open access)

Selective Lipid Absorption

An experiment was designed to study in the same animal any preferential absorption of a free fatty acid in the presence of a triglyceride of the same fatty acid. Rats were administered a mixture of free fatty acid and its triglyceride labeled with carbon-13 and carbon-14 respectively. Each isotope in the fed lipid and in the lipid recovered from the gastrointestinal tract was measured. The isotope effect, if any, was studied by administering a mixture of palmitic acid-1-C13 and palmitic acid-1-C14.
Date: January 1960
Creator: Marcia, John Albion
System: The UNT Digital Library
Kinetic Investigation of Atomic Hydrogen with Sulfur-Containing Species (open access)

Kinetic Investigation of Atomic Hydrogen with Sulfur-Containing Species

The reactions of atomic hydrogen with methanethiol and that of atomic hydrogen with carbon disulfide were studied experimentally using flash-photolysis resonance-fluorescence techniques. Rate constants were determined over a range of temperatures and pressures, and through analysis and comparison to theoretical work details of the reactions were ascertained.
Date: December 2014
Creator: Kerr, Katherine Elaine
System: The UNT Digital Library
Utilizing Rapid Mass Spectrometry Techniques to Profile Illicit Drugs from Start to Finish (open access)

Utilizing Rapid Mass Spectrometry Techniques to Profile Illicit Drugs from Start to Finish

The increasingly complex world of illicit chemistry has created a need for rapid, selective means of determining the threat posed by new drugs as they are encountered by law enforcement personnel. To streamline this process, the entirety of the problem, from the production of illicit drugs all the way to the final analysis have been investigated. A series of N-alkylated phenethylamine analogues were synthesized in a shotgun method and subjected to direct-infusion analysis. A range of products were detected without the need for time-consuming purification steps, which was extended to novel pharmacological and receptor-binding assays where mass spectrometry is used as a detector. This direct-infusion technique was also applied to studies of methamphetamine and fentanyl production to preemptively determine improvements to common reaction conditions and explore the origins of common impurities. The ability to utilize these rapid techniques directly from the fume hood has also been critically reviewed to highlight gaps in current research and opportunities for improvement. When combined, these studies seek to provide a means for rapid, simplified analysis of illicit drugs to improve the quality of data and dramatically increase throughput.
Date: August 2018
Creator: McBride, Ethan
System: The UNT Digital Library
Studies on the Biological Activity of N-nitrosamines (open access)

Studies on the Biological Activity of N-nitrosamines

Two aspects of the biological activity of N-nitrosamines were studied. First, the effect of ascorbate on the mutagenicity of N-nitrosopiperidines was studied in the Ames Salmanella/ mammalian microsome mutagenicity test. The addition of ascorbate significantly enhanced the mutagenicity of these compounds. This enhancement was selective for N-nitrosamines suggesting a possible role of ascorbate in N-nitrosamine induced carcinogenicity. Second, the technique of velocity sedimentation in alkaline sucrose density gradients was applied to the detection of N-nitrosamine induced DNA damage in Balb/c 3T3 cells. This technique detected N-nitrosamine induced DNA damage when the cells were made permeable before treatment. This technique compares favorably with other test systems used to evaluate N-nitrosamines and should be useful in further studies of N-nitrosamines.
Date: August 1980
Creator: Barton, Rodney A. (Rodney Alan)
System: The UNT Digital Library
Analysis of Trace Amounts of Adulterants Found in Powders/Supplements Utilizing Direct Inject, Nanomanipulation, and Mass Spectrometry (open access)

Analysis of Trace Amounts of Adulterants Found in Powders/Supplements Utilizing Direct Inject, Nanomanipulation, and Mass Spectrometry

The regulations of many food products in the United States have been made and followed very well but unfortunately some products are not put under such rigorous standards as others. This leads to products being sold, that are thought to be healthy, but in reality contain unknown ingredients that may be hazardous to the consumers. With the use of several instrumentations and techniques the detection, characterization and identification of these unknown contaminates can be determined. Both the AZ-100 and the TE2000 inverted microscope were used for visual characterizations, image collection and to help guide the extraction. Direct analyte-probed nanoextraction (DAPNe) technique and nanospray ionization mass spectrometry (NSI-MS) was the technique used for examination and identification of all adulterants. A Raman imaging technique was than introduced and has proven to be a rapid, non-destructive and distinctive way to localize a specific adulterant. By compiling these techniques then applying them to the FDA supplied test samples three major adulterants were detected and identified.
Date: August 2016
Creator: Nnaji, Chinyere
System: The UNT Digital Library
Predictive Modeling of Novel Mutations to DNA-Editing Metalloenzymes and Development of Improved QM/MM Methods (open access)

Predictive Modeling of Novel Mutations to DNA-Editing Metalloenzymes and Development of Improved QM/MM Methods

Molecular dynamics simulations and QM/MM calculations can provide insights into the structure and function of enzymes as well as changes due to mutations of the protein sequence.
Date: December 2021
Creator: Hix, Mark Alan
System: The UNT Digital Library
Mass Spectrometry Guided Development of a Controlled Release Nanotransfersome Transdermal Drug Delivery System (open access)

Mass Spectrometry Guided Development of a Controlled Release Nanotransfersome Transdermal Drug Delivery System

Poor medical adherence attributed to patient compliance has impacted the medical community, at times, in a deleterious fashion. To combat this, the medical community has attempted to provide therapeutics in the form of absorption enhancing techniques. To improve the absorption rate techniques such as drug encapsulation using proteins, liposomes, or nanotransfersomes have been developed using mass spectrometry. These techniques, have aided in the enhanced absorption of analytes with low bioavailability, including curcumin, simvastatin, and lysozyme. Specifically, mass spectrometry allows for the development and monitoring of nanotransfersome encapsulated analytes and the permeation across the dermal membrane. This transdermal delivery would eliminate the problems encountered during first pass metabolism, while allowing for higher concentrations of analyte to be maintained in the blood serum. This can be coupled to a thermosensitive gelatin that provides for a dose control mechanism to be accomplished, allowing multiple doses to be delivered using one transdermal patch system. The novel delivery system developed using mass spectrometry, allows the analyte to be delivered into the circulatory system at a controlled dosage, via transdermal absorption. This system will aid in eliminating problems associated with patient compliance, as the patient is no longer reliant on memory to self-dose. Further, this system …
Date: December 2020
Creator: Kiselak, Thomas Dieter
System: The UNT Digital Library
Acenaphthene and 1,10-Phenanthroline-Fused Βeta-Functionalized Porphyrins (open access)

Acenaphthene and 1,10-Phenanthroline-Fused Βeta-Functionalized Porphyrins

A series of acene-fused porphyrins and 1,10-phenanthroline-fused porphyrins were synthesized and characterized via NMR spectroscopy and mass spectrometry. The acene-fused porphyrins exhibit unique optoelectronic properties, most notably they exhibit highly red-shifted absorption bands. The 1,10-phenanthroline-fused porphyrins are of interest for their ability to bond to as variety of metals to form chelation complexes.
Date: December 2023
Creator: Arvidson, Jacob Randall
System: The UNT Digital Library
Modeling Transition Metal Chemistry for Catalytic Functionalization of Molecules (open access)

Modeling Transition Metal Chemistry for Catalytic Functionalization of Molecules

The diversity of transition metal complexes allows for a wide range of chemical processes to be mediated by the metal, from catalysis to surface chemistry. Investigations into the structure and electronic configuration of transition metal complexes allow for tuning of desired species by modifications to the ligands and/or metals to achieve more efficient thermodynamics and kinetics for the process of interest. Transition metals, often used in catalysts for a number of important processes, require detailed descriptions of intermediates, transition states and products to fully characterize a reaction mechanism(s) in order to design more active and efficient catalysts. Computational investigations into inorganic catalysts are explored with the aim of understanding the activity of each species and how modifications of supporting ligands, co-ligands and metals vary the interaction along the reaction pathway. Reported results give important insight into the development of the most active complexes in addition to determining the least active complexes to aid experimental development. This report first investigates the mechanisms of two unique transfer reactions: 1) formation of low coordinate nickel-nitrene ((P~P)Ni=NR; P~P = 1,2-bis(dihydrophosphino)-ethane or 1,2-bis(difluoromethylphosphino)-ethane) complexes as catalysts for nitrogen atom transfer and 2) oxidation of a triphosphorus niobium complex, [(η2-P3SnPh3)Nb(OMe)3], for the transfer of the phosphorus …
Date: August 2011
Creator: Morello, Glenn
System: The UNT Digital Library