Doctor of Philosophy, Miami University, 2012, Chemistry and Biochemistry

This dissertation contains six chapters demonstrating the use of Terahertz Time-Domain spectroscopy and imaging in a variety of applications, from the principle analysis of observed absorption features to the quantitation of threat agents. Chapter 1 focuses on the background of Terahertz, starting with its roots in Microwave and Infrared Spectroscopies and continuing on to modern time-domain techniques that dominate the field at present. Terahertz's interaction with different types of matter, various instrumentation setups, and several types of common time-domain measurements are also discussed. Chapter 2 discusses two separate studies attempting to further the understanding of collective mode absorption peaks observed in the THz spectral region. Absorption peaks found in the THz region of crystalline solids are typically described generically as collective modes or computationally analyzed with no supporting experimental data. These two studies demonstrate an experimental method that can be used concurrently with computational techniques to elucidate a more complete understanding of observed collective modes. Chapter 3 probes the feasibility of detecting a possible threat agent, dipicolinic acid, which is a major component in bacterial spores, such as Anthrax. It focuses on qualitative discovery and the ability to quantify its presence with Terahertz Spectroscopy and imaging. Chapter 4 presents a library of quality cryogenic and room temperature spectra for the 20 standard amino acids to be used as a reference for future research. In addition, trends observed by the groups of amino acids were assessed. Chapter 5 examines the spectral properties of a large biomolecule, heparin, in the terahertz spectral region. Several sample configurations are investigated, from heparin as-is to crystallized nitric acid digestion remnants. A novel trace metal analysis method of heparin utilizing Inductively Coupled Plasma Optical Emission Spectroscopy is also presented. Chapter 6 d (open full item for complete abstract)

Committee: Gilbert E. Pacey PhD (Advisor); Shouzhong Zou PhD (Committee Chair); Richard T. Taylor PhD (Advisor); C. Scott Hartley PhD (Committee Member); James R. Gord PhD (Committee Member) Subjects: Analytical Chemistry

Master of Science, The Ohio State University, 2009, Food Science and Nutrition

Foods we consume are rarely sterile and most foods host a mixture of microorganisms that range from beneficial cultures to pathogenic varieties. In any food industry, microbial analysis forms an integral part of qualitative analysis. Conventional microbial tests usually require several steps of analysis in order to make a positive identification of the microorganism in interest. New methods for rapid analysis of microorganisms are being constantly developed as an alternate to conventional microbial analysis. The objective of this study was to explore the potential of Fourier transform infrared (FTIR) spectroscopy in rapid microbial analysis: classification of Swiss cheese cultures and quantification of dipicolinic acid release from spores. For the classification of Swiss cheese cultures, forty four strains of starter and non-starter cultures including Streptococcus thermophilus, Propionibacterium freudenreichii and Lactobacillus spp., previously verified by PFGE, were grown in broth media, centrifuged and the pellets were resuspended in saline solution. The suspension was applied onto hydrophobic grid membrane filters and the dried filters were analyzed using FTIR microscope to obtain the sample spectra. Collected spectra were statistically analyzed by a Soft independent modeling of class analogy (SIMCA) to develop individual classification models for strains of Streptococcus thermophilus, Propionibacterium freudenreichii and Lactobacillus spp. strains. The developed method allowed for rapid classification of several Swiss cheese starter and non-starter cultures at the strain level. This information provides a detailed overview of the microbiological status, which would enable corrective measures to be taken early in the cheese making process, limiting production of inferior quality cheese and minimizing defects. For the quantification of Dipicolinic acid (DPA) release from bacterial spores, Bacillus amyloliquefaciens Fad 82 cultures grown on two different sporulat (open full item for complete abstract)

Committee: Luis E. Rodriguez-Saona PhD (Advisor); W. James Harper PhD (Committee Member); Culbertson Jeff PhD (Committee Member) Subjects: Food Science