UNT Theses and Dissertations - 762 Matching Results

Search Results

prev Results: 529 - 552 next
open access

The Correlation Between Carbon-Proton and Proton-Proton Coupling Constants

Description: The correlation between the carbon-proton and proton-proton coupling constants have been studied in various 13 systems. Isocrotonic acid-carboxyl-3C, crotonic acid- 13 13 carboxyl-3C, and 5-norbornene-2-carboxylic acid-carboxyl-3C- 1,5,6,7,7-hexachloro were synthesized and their carbonproton coupling constants were analyzed. Nmr studies showed the magnitudes of the carbon-proton coupling constants to correlate well with analogous protonproton coupling constants, although the values of the coupl… more
Date: December 1975
Creator: Seiwell, Ruth R.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Denaturation, Renaturation and Other Structural Studies on Phosphoglucose Isomerases

Description: Structural properties of phosphoglucose isomerases isolated from a variety of species have been compared by peptide fingerprinting, predicted amino acid sequence homologies and by denaturation and renaturation studies. The enzymes are more readily denatured in guanidinium chloride than in urea, and the isomerase isolated from yeast is more stable toward acid pH than the rabbit muscle enzyme. The rates of guanidinium chloride-induced denaturation are markedly increased by ionic strength and decr… more
Date: December 1975
Creator: Young, Clint D.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Magnetic Properties of Copper (II) Complexes of Schiff Bases

Description: The synthesis and characterization of two new Schiff base copper(II) complexes are reported. These are Cu(acac: 2-amino-l-phenylethanol) and Cu(acac:2-amino-l-butanol). The ligands, derived from acetylacetone and the appropriate aminoalcohol, are dibasic tridentates with 0,N,O donor atoms. The magnetic properties of the complexes were studied at several temperatures between 78 OK and 296 OK. The magnetic moment of Cu(acac:2-amino-l-phenylethanol) varied little with temperature, and that of Cu(a… more
Date: August 1975
Creator: Jones, William James
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Stereochemical Elucidation Of The Tetrahydro [2.2]paracyclophane System

Description: The purpose of this investigation is to study the Birch reduction products of [2.2lparacyclophane and of [2.2]paracyclophane- 2-carboxylic acid. The tetrahydro Birch reduction product of [2.2]paracyclophane is shown to be dl stereoisomer, with the olefins of the upper deck only partially overlapping with the olefins of the lower deck. This stereochemical elucidation is accomplished by means of a complete proton nmr analysis of the tetraepoxide derivative. A proposed mechanism supported by VB (v… more
Date: August 1975
Creator: Song, Ban-Huat
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Crystal and Molecular Structure of 2, 2' bipyridylglycinatochloro Copper (II) Dihydrate

Description: The three-dimensional x-ray structure of 2,2'-bipyridylglycinatochloro copper(II) dihydrate has been fully refined to a final R factor of 0.081. The bipyridyl and glycine ligands are arranged about the central copper atom in a square planar configuration while the chlorine atom is 2.635 angstroms above this plane directly over the copper atom. This unusually long distance is explained by the positioning of a glycine group on the opposite side of the square plane, resulting in a distorted octahe… more
Date: May 1975
Creator: Neitzel, Conrad J.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Hyperconjugative Interactions in Silylanilines

Description: The purpose of the present work is to study the bonding interactions between the substituents and the ring π system for a series of ortho and para MeₙH₃₋ₙM (M = C or Si, n = 0-3) substituted N,N-dimethylaniline . Both ground and excited-state interactions were studied and their magnitudes determined. The experimental data were then used in conjunction with molecular orbital calculations to differentiate among inductive, hyperconjugative, and d-pπ interactions on the ground and excited states. O… more
Date: May 1975
Creator: Jung, Il Nam
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Isolation and Characterization of Proteus vulgaris Methylglyoxal Synthetase

Description: Methylglyoxal synthetase, which catalyzes the formation of methylglyoxal and inorganic phosphate from dihydroxyacetone phosphate, was found in extracts of Proteus vulgaris. An efficient purification procedure utilizing ion exchange column chromatography and isoelectric focusing has been developed. Homogeneity of the enzyme preparation was confirmed by polyacrylamide gel electrophoresis and rechromatography.Two components of methylglyoxal synthetase were obtained upon isoelectric focusing. A com… more
Date: May 1975
Creator: Tsai, Pei-Kuo
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Synthesis and Study of Glutaryl-S-(ω-aminoalkyl)-L-cysteinylglycines as Inhibitors of Glyoxalase I

Description: This thesis describes the synthesis and preliminary enzymatic study of glutaryl-S-(8-aminooctyl)-L-cysteinylglycine and glutaryl-S-(10-aminodecyl)-L-cysteinylglycine as inhibitors of glyoxalase I. These analogs of glutathione were prepared as potential ligands for affinity chromatography purification of glyoxalase I. The compounds were synthesized by a seven-step procedure in overall yields of 24% for the octyl analog and 33% for the decyl analog. Both compounds exhibited mixed type inhibition … more
Date: May 1975
Creator: Phillips, Gerald Wayne
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Inhibitors of Dihydrofolate Reductase, 8-Oxapteridines

Description: The biological activities of some homeosterically related analogs of dihydrofolic acid have been examined involving pyrimido[4,5-b][l,4]oxazine (8-oxapteridine) derivatives. It is anticipated that these compounds might interfere with the essential intermediary metabolic functions of the vitamin and thus serve as potential chemotherapeutic agents. Preliminary toxicity studies in microbial assay systems were disappointing; however, inhibitory effects were demonstrated in cell free enzyme systems… more
Date: December 1974
Creator: Lin, Shwu-Ching H.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Long-Range Carbon-13--Carbon-13 Spin-Spin Coupling Constants

Description: The study consists of three major areas of research. First, the dihedral angle dependence of vicinal carbon-carbon coupling constants is determined for aliphatic and alicyclic carboxylic acids wherein the formal hybridization and substituents are held constant. Second, the magnitudes and relative signs of long-range carbon-carbon coupling constants in a. triple- 13 C-labeled system are determined and compared with carbon-proton and/or proton-proton coupling constants in geometrically similar co… more
Date: December 1974
Creator: Miller, Denis E.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Properties of Molecular Rydberg States

Description: Many of the bands in the vapor-phase far-ultraviolet absorption spectra of simple molecules can often be fit to mathematical progressions referred to as molecular Rydberg series. The name Rydberg arises from the similarity between the Rydberg formula for the atomic hydrogen spectrum and the formulae for the progressions found in molecular spectra. The theories of molecular Rydberg transitions and states are discussed in terms of the inferences that have been made in the past from the available … more
Date: December 1974
Creator: Scott, John Delmoth
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Structure-Activity Studies of Halopyrethroids

Description: The structures of the new pyrethroids were elucidated utilizing nuclear magnetic spectroscopy and elemental analysis. The biological activity of the pyrethroids has been evaluated for houseflies and yellow fever mosquitoes. A correlation of increase in rapid knockdown and toxicity with decrease in size of halogen has been made. The most effective compound, the difluorovinyl ester, has a toxicity of 123 times greater than pyrethrins. This degree of toxicity has not previously been reported for a… more
Date: December 1974
Creator: Brown, Dale Gordon
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Vacuum Ultraviolet Spectra of Cyclohexane, Cyclohexene, 1,4-Cyclohexadiene, Isotetralin, and Several Methyl Substituted Analogs

Description: A paucity of literature exists on the Independent System analysis of adjacent, parallel transition dipoles. Applying this theory and certain spectral information semiemperical calculations were made to predict absorption profiles and band intensities. To aid in the assignment of the 7*+7 absorption bands it was necessary to obtain the vacuum ultraviolet spectra of cyclohexane and cyclohexene. Because the spectra of these molecules contained sharp, atomic-like absorption bands a Rydberg series c… more
Date: December 1974
Creator: Tidwell, Edgar Rhea
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Mechanism of Formation and Lifetimes of Halogenated Ketenes

Description: The investigation presented here is in two parts: a mechanistic study of the triethylamine dehydrohalogenation of ac-haloacid halides to form halogenated ketenes and a study of steric influence upon ketene lifetimes. The first part of this research deals with the mechanism of the dehydrohalogenation reaction. Two acid halides, isobutyryl chloride and a-chloropropionyl chloride, appeared to represent two mechanistic extremes for this reaction with triethylamine. Isobutyryl chloride reacted with … more
Date: August 1974
Creator: Scherubel, Gary
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Isozymes and In Vivo Activity of Triosephosphate Isomerase

Description: The distribution of isozymes of triosephosphate isomerase was normal in all human tissues examined. This finding argues against the existence of tissue-specific isozymes. Normal distributions of isozymes were also found in patients with cri-du-chat syndrome. Thus it is unlikely that a gene for triosephosphate isomerase is located on the short arm of chromosome five in man. When triosephosphate isomerases from a wide range of species were examined by starch gel electrophoresis, definite evolutio… more
Date: May 1974
Creator: Snapka, Robert Morris
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Studies Concerning Asparagine Metabolism in Lactobacillus plantarum

Description: This study is concerned with the metabolism of L-asparagine in Lactobacillus plantarum (ATCC 8014). Theprimary area of investigation is the preliminary characterization of a previously unreported L-asparaginase enzyme in L. plantarum. This L-asparaginase was determined to be an inducible enzyme with variations in its activity level according to the L-asparagine level in the growth medium. L-Glutaminase could not be induced in this organism by L-glutamine, nor would L-glutamine induce the aspar… more
Date: May 1974
Creator: McCue, Bette Ann
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Magnetic Properties of Copper (II) Complexes of N-(Hydroxyalkyl) Pyrrole-2-Aldimines

Description: In this work magnetic properties of copper(II) complexes on N-(hydroxyalkyl) pyrrole-2-aldimines were investigated by various techniques, one of which was magnetic susceptibility. Magnetic moments are not directly determined experimentally, but magnetic susceptibilities are.
Date: December 1973
Creator: Pauley, Charles Richard
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Conformational Analogs of Some Phytoactive Compounds

Description: In an effort to determine if there is a specific conformational structure which is most effective at the appropriate active physiological site, the synthesis of a group of sterically restricted analogs was undertaken. A portion of the polymethylene carbon skeleton of glutaric acid was replaced by selected aromatic carbons in benzenedicarboxylic acids to produce a series of ridged conformers, and the relative plant growth regulating properties of these derivatives were determined.
Date: August 1973
Creator: Skelton, Wm. Paul
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Synthesis and Study of Metabolic Antagonists

Description: The central nature of nicotinamide in metabolic processes as a part of the NAD and NADP coenzyme systems prompted the synthesis of a series of N-nicotinyl- and N-isonicotinyl-N'- (substituted)ureas as potential metabolite antagonists of the vitamin. The compounds which were synthesized may be represented by the following general structure, where R = hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-hexyl, cyclohexyl, phenyl and a-naphthyl. The observed toxicity of the N-nicotin… more
Date: August 1973
Creator: Masingale, Robert Edesta
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Experimental and Theoretical Study of Electronic Transitions in Phosphorus, Phosphoryl, and Thiophosphoryl Trichlorofluorides

Description: This thesis is an investigation of the vacuum uv spectra of the phosphorus, phosphoryl, and thiophosphoryl trichlorofluorides in the region 1250 to 3000A. Assignments for absorption bands are made utilizing results from photoelectron spectra and ab initio calculations, oscillator strengths for absorption bands, and CNDO/2 molecular orbital calculations. Results from CNDO/2 calculations are compared with theoretical calculations, and experimental data are discussed with regard to the bonding in … more
Date: May 1973
Creator: McAdams, Mary Jane
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Halogenated 2-Oxetanones

Description: The purpose of this investigation is threefold: (1) to examine in detail the cycloaddition of halogenated ketenes and carbonyl compounds, (2) to study the decarboxylation of the resulting halogenated 2-oxetanones,and (3) to investigate the effect of halogens in the halogenated 2-oxetanones on the nucleophilic addition reaction.
Date: May 1973
Creator: Patel, Arvind D.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Studies Concerning the Production of Lactobacillic Acid in Lactobacillus Plantarum

Description: This study is concerned with certain factors affecting the content of lactobacillic acid in Lactobacillus plantarum. Three main areas of investigation are reported herein. The effects of both the oxygen tension and the pH of the culture medium on the accumulation of lactobacillic acid were determined. In addition, monolayer studies were conducted to determine the influence of cyclopropane fatty acid content on the molecular packing of membrane lipids.
Date: May 1973
Creator: Halper, Laura Ann
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Kinetics of Reactions of Substituted Group VI B Metal Carbonyls with Phosphites

Description: The problem with which this investigation is concerned is twofold. The initial part of the problem was to prepare a non-sterically demanding bidentate phosphine ligand, 1,2-bis-(Phosphino)ethane, (P-en), and to determine the kinetics of (P-en)Mo(CO)4 with phosphites via spectrophotometric methods in an attempt to determine if steric effects are directing the type of mechanism followed.
Date: August 1972
Creator: Rettenmaier, Albert J.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
Back to Top of Screen