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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Gas-phase fragmentation chemistry of protonated peptide ions /

Bythell, Benjamin James. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.
2

The synthesis of medium-sized ring containing libraries using oxidative fragmentation and rearrangement strategies /

Jones, Alan Morenc. January 2009 (has links)
Thesis (Ph.D.) - University of St Andrews, March 2009. / Restricted until 17th March 2011.
3

Development of fragmentation techniques in mass spectrometry for biological applications /

Ji, Hong. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.
4

A computational study of the chemistry of 3-phenylpropyl radicals

Modglin, James D. January 2005 (has links)
Using computational methods, we have investigated the chemistry of 3-phenylpropyl radical systems. These systems are of importance to polymer chemistry as free radical additions involving these species are integral in the production of styrene-containing plastics. Although the addition reactions have been well studied, the other reaction pathways, namely f3-fragmentation and cyclization, have not been as comprehensively studied. As a result, our computational study involved 3-phenylpropyl radical systems that had been systematically mono-substituted at five positions, two on the propyl chain and three on the aromatic ring. This computational analysis consisted of calculation of optimized geometries and energies for reactants, products, and transition states, followed by examination of derived thermochemical quantities (enthalpies of activation and reaction), and critical structural parameters (transition bond lengths and bond angles) of the systems. Finally correlation of structure and reactivity of the various systems was attempted. Density functional theory (DFT) using the B3-LYP functional and the 6-31 G(d) basis set was selected as the level of theory. / Department of Chemistry
5

Characterization of the sequence and substrate reactivity of dihydroneopterin aldolase and its site-directed mutants by tandem mass spectrometry

Scherperel, Gwynyth. January 2006 (has links)
Thesis (M.S.)--Michigan State University. Dept. of Chemistry, 2006. / Title from PDF t.p. (viewed on Nov. 20, 2008) Includes bibliographical references (p. 105-110). Also issued in print.
6

Examination of fragmentations of protonated and metallated amino acids, oligopeptides, and their building blocks using triple quadrupole mass spectrometry /

El Aribi, Houssain. January 2003 (has links)
Thesis (Ph.D.)--York University, 2003. Graduate Programme in Chemistry. / Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ99165
7

Target identification and validation studies in chemical biology & Synthesis of medium-sized ring containing compounds via oxidative fragmentation

Liu, Gu January 2010 (has links)
Part I of this thesis describes the development of bioactive small molecules of relevance to the study of the apicomlexan parasite Toxoplasma gondii into useful chemical tools. The research includes the target identification and validation studies, using both chemical and biological methods. Chapter 1 provides an overview of chemical genetics with a particular emphasis on methods for the identification of the protein targets of bioactive small molecules. The concept of biochemical protein target identification techniques was introduced with a detailed discussion of interesting applications from the literature. Chapter 2 focuses on the development of a tetrahydro-β-carboline based lead molecule into a chemical tool through target identification studies. The structure activity relationship (SAR) data associated with this core structure, the design of a chemical inducer of dimerisation (CID) and the synthesis of this CID are discussed in detail. Chapter 3 described work done to identify the potential protein target(s) of Conoidin A. Experiments to assess whether Conoidin A can inhibit a proposed target in vitro are also included. Further optimisation of this structural class to develop more potent inhibitors is discussed in the second part of this chapter. Part II of this thesis describes the development of methods for the synthesis of medium-sized ring containing compounds using oxidative fragmentation and rearrangement strategies. Chapter 5 provides an overview of the existing oxidative fragmentation methodology, with an emphasis on the use of oxidative fragmentation reactions for the synthesis of medium-sized ring systems (8-11 ring atoms). Chapter 6 focuses on using the established oxidative fragmentation method in the oxizino carbazolone system to investigate the diasteroselectivity of this reaction. Possible mechanisms for this transformation are investigated and discussed using both chemical and computational methods. An interesting rearrangement reaction has also been observed during this study. Chapter 7 focuses on developing an asymmetric oxidative fragmentation method, for use in the diazabenz[e]aceathrylenes system. Asymmetric oxidative fragmentation reactions using [Ru(pybox)(pydic)] catalysts are discussed. Attempts to optimise the enantiomeric excesses of the reaction by varying reaction conditions and substituents in the substrate are also included.
8

Development of Total Vaporization Solid Phase Microextraction and Its Application to Explosives and Automotive Racing

Bors, Dana E. January 2015 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Pipe bombs are a common form of improvised explosive device, due in part to their ease of construction. Despite their simplistic nature, the lethality of pipe bombs should not be dismissed. Due to the risk of harm and their commonality, research into the pipe bomb deflagration process and subsequent chemical analysis is necessary. The laboratory examination of pipe bomb fragments begins with a visual examination. While this is presumptive in nature, hypotheses formed here can lead to subsequent confirmatory exams. The purpose of this study was to measure the mass and velocity of pipe bomb fragments using high speed video. These values were used to discern any trends in container type (PVC or black/galvanized steel), energetic filler (Pyrodex or double base smokeless powder), and ambient temperature (13°C and -8°C). The results show patterns based on container type, energetic filler, and temperature. The second stage of a laboratory exam is chemical analysis to identify any explosive that may be present. Legality calls for identification only, not quantitation. The purpose of this study is to quantitate the amount of explosive residue on post-blast pipe bomb fragments. By doing so, the instrumental sensitivities required for this type of analysis will be known. Additionally, a distribution of the residue will be mapped to provide insight into the deflagration process of a device. This project used a novel sampling technique called total vaporization solid phase microextraction. The method was optimized for nitroglycerin, the main energetic in double base smokeless powder. Detection limits are in the part per billion range. Results show that the concentration of residue is not uniform, and the highest concentration is located on the endcaps regardless of container type. Total vaporization solid phase microextraction was also applied to automotive racing samples of interest to the National Hot Rod Association. The purpose of this project is two-fold; safety of the race teams in the form of dragstrip adhesive consistency and monitoring in the form of fuel testing for illegal adulteration. A suite of analyses, including gas chromatography mass spectrometry, infrared spectroscopy, and evaporation rate, were developed for the testing of dragstrip adhesives. Gas chromatography mass spectrometry methods were developed for both nitromethane based fuel as well as racing gasolines. Analyses of fuel from post-race cars were able to detect evidence of adulteration. Not only was a novel technique developed and optimized, but it was successfully implemented in the analysis of two different analytes, explosive residue and racing gasoline. TV-SPME shows tremendous promise for the future in its ability to analyze a broad spectrum of analytes.

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