The novel diterpenoid taxol isolated from the western yew Taxus brevifolia is one of the most important lead compounds to emerge from the search for anticancer agents from plants. It shows consistent clinical activity against ovarian cancer and may also be active against other cancers. In this study, the preparation of various taxol derivatives was investigated, with the objective of better understanding the structural requirements for activity in the taxol series. The 7-hydroxyl group of taxol was derivatized with a photoaffinity label and other reagents as a beginning of the project to understand the interaction of taxol and tubulin, and the activity of all the derivatives in a tubulin assay was determined. A study of the deacylation and reacylation reactions of baccatin 111 was carried out in order to find conditions suitable for the preparation of 2-debenzoylbaccatin Ill , and thus 2-debenzoyltaxol. Finally, the reactions of taxol with various electrophilic reagents were investigated, and the structures of products with an opened oxetane ring and/or contracted ring A were determined. Biological assay results are reported on many of the compounds in this investigation. / Ph. D.

This dissertation is concerned with the evaluation of a robust modification of existing methodology within the classical inference framework. This results in an F-test based on the robust weights used in arriving at the M or Bounded-Influence estimates. These estimates are known to be robust to outliers and highly influential points, respectively. The first part of this evaluation involves a Monte Carlo power study, under violations of the classical assumptions, of this F-test based on robust weights and several other proposed robust tests. It is shown in simulation studies that, under certain conditions, the F-test based on robust weights is a much more powerful test than the classical F -test, and compares favorably to all other proposals studied. The second part involves the development of the influence curve (IC) for the F-test based on robust weights and one empirical approximation to the IC, the Sample Influence Curve (SIC). It is shown for two sample data sets that the SIC demonstrates the resistance to unusual points of the F-test based on robust weights. / Ph. D.

Convergence rates are analyzed for Recursive Prediction (Output) Error Methods (RPEM) in the identification of linear state-space systems from (noisy) impulse response data) RPEM algorithms are derived which are suitable for the identification of the parameters in arbitrary state-space structures. Deterministic and stochastic versions of these identification algorithms are presented. These two classes indicate the number of realizations used in the identification, not the presence or absence of noise. The convergence analysis uses the eigen-information of the correlation matrix (really its inverse, the Fisher information matrix) for a chosen parameterization. This analysis explains why various state-space structures have different convergence properties, 1.e., why for the same system the estimation processes corresponding to different identification structures converge at different rates. The eigen-information of the parameter information matrix relates the system sensitivity and numerical conditioning in a manner which provides insight into the identification process. The relevant eigen-information is combined in the proposed scalar convergence time constant +. One important result is that identification of the usually identified direct form II parameters (the standard ARMA parameters) does not necessarily yield the fastest parameter set convergence for the system being identified. Identification from arbitrary input is also briefly considered, as is identification when the model order is different from the “true” system order. / Ph. D.

The glpF gene, which encodes a cytoplasmic membrane protein that facilitates the diffusion of glycerol into the cell, and the glpK gene, which encodes glycerol kinase, map near minute 88 on the linkage map of Escherichia coli K-12. In the present work, the nucleotide sequence of the 843 base Pair glpF gene, 430 base pairs of the glipK gene, and the intervening sequence between the two genes were determined. The control region for the glpFK operon was identified and sequenced. The gipK gene product was purified to near homogeneity by streptomycin sulfate and ammonium sulfate fractionation with subsequent DEAE Sephadex chromatography. N-terminal amino acid analysis identified the startpoint of translation for the gipK gene. The transcription start site was identified 71 base pairs upstream from the proposed translation start codon for glpF. Preceding the transcription start site were -10 and -35 sequences Similar to the consensus sequences for gram bacterial promoter elements. DNase I footprinting was used to identify two binding sites for the CAMP-cAMP receptor protein (CRP) complex upstream from and overlapping the putative -35 sequence. Four binding sites for the glp repressor were located sequentially along the DNA extending from -89 (relative to the start point of transcription) to within the -10 region. Two additional repressor binding sites were identified within the glpK coding region. Interaction of these operator sites with those in the control region was identified. The affinity of the gilp repressor for the control regions of the glpD, glpACB-gipTQ, and glpFK operons was compared by titration studies using a strain harboring a glpT:lacZ fusion and a glpRⁿ mutation. / Ph. D.

Burgers' equation is a one-dimensional simple model for convection-diffusion phenomena such as shock waves, supersonic flow about airfoils, traffic flows, acoustic transmission, etc. For high Reynolds number, the open-loop system (no control) produces steep gradients due to the nonlinear nature of the convection. The steep gradients are stabilized by feedback control laws. In this phase, sufficient conditions for the control input functions and the location of sensors are obtained. Also, explicit exponential decay rates for open-loop and closed-loop systems are obtained. Numerical experiments are given to illustrate some of typical results on convergence and stability. / Ph. D.

Hexenyl functionalized poly(dimethylsiloxane) and methacryloyloxy functionalized poly(methyl methacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) macromonomers were synthesized using living polymerization techniques. The PDMS macromonomers were prepared by the anionic ring-opening polymerization of hexamethylcyclotrisiloxane followed by termination with a functionalized chlorosilane derivative. The methacryloyloxy functionalized PMMA macromonomers were prepared using group transfer polymerization with a protected hydroxyl functional initiator. The molar masses of the macromonomers ranged from 1000 g/mol up to 20000 g/mol with narrow molar mass distributions, less than 1.1, and high percent functionalities. The hexenyl functionalized PDMS macromonomers, having a range of molar masses, were statistically terpolymerized with l-butene and sulfur dioxide to yield poly(l-butene sulfone)-g-PDMS copolymers of various chemical compositions up to 20 wt% PDMS. The bulk and surface phase morphologies were investigated using DSC, TEM, XPS, and water contact angle measurements. The graft copolymer was shown to be an excellent resist for electron beam lithography with a 44u4C/cm4 sensitivity and a 33:1 etch ratio relative to a cross linked novolac resin. The 7000 g/mol methacryloyloxy functionalized PMMA macromonomers were copolymerized anionically with MMA to yield PMMA-g-PMMA polymers having absolute molar mass distributions less than 1.1 containing from 5 wt% to 40 wt% of the macromonomer at constant overall molar mass of 250000 g/mol. The graft polymers were utilized as model homopolymers exhibiting long chain branching. The methacryloyloxy functionalized PDMS macromonomers were free radically and anionically copolymerized with MMA to yield PMMA-g-PDMS copolymers. The graft copolymers were fractionated and their chemical composition distributions were determined as a function of copolymerization mechanism. In addition, preliminary studies were started using aluminum-27 NMR to study several different aluminum porphyrins based on (5,10,15,20-tetraphenyl) porphine (TPPH₂) . The aluminum porphyrins were formed by reacting trimethylaluminum with TPPH₂ to yield TPPAIMe. The resulting aluminum porphyrin was modified by adding a stoichiometric amount of various carboxylic acids to form aluminum porphyrin carboxylates that had varying steric and electronic effects on the macrocycle. / Ph. D.

Camera motion blur was examined in two experiments, in an attempt to behaviorally validate candidate predictors of the associated degradation in photographic image quality. In the first experiment, motion of a hand-held 35-mm single-lens-reflex camera was measured using inertial sensors while film was simultaneously exposed. Thirty-two subjects photographed two studio scenes at 1/60-s, 1/30-s, 1/15-s, and 1/8-s shutter speeds, replicated four times. Several spatial image quality metrics (blur size, Subjective Quality Factor, SQF; Modulation Transfer Function ,Area, MTFA; and Equivalent Passband, Ne), derived analytically from the motion data, were used as dependent measures for statistical analysis. All three modulation-transfer-function (MTF)-based analytic quality metrics were strongly intercorrelated. Under these measures, the 1/60-s shutter speed yielded significantly higher quality photographs than the other speeds. The 1/8-s condition proved the worst. A difference between the 1/30-s and 1/15-s conditions was not reliably supported under the MTF-based metrics, although a significantly greater blur size resulted on average in the longer exposure. Tripod-mounted exposures compared favorably with the hand-held shots at 1/15 s and 1/8 s, but differences were not statistically supported at the two faster speeds. In the second experiment, 16 prints of each scene were selected from those collected in the first experiment. The log-transformed analytic SQF values were used to select the prints, ranging from worst to best at equal increments. Measures of perceived image quality and sharpness were derived from psychophysical judgments by 48 observers. Linear regression analyses identified several analytic models that predicted substantial amounts of the variance in mean judgments across all observers. The analytic SQF, MTFA, and N_e metrics based on the products of the unidimensional values in x and y each accounted for roughly 90% of the variance in relative judgments. The use of any of these measures is recommended for the evaluation of motion blur in future camera-shake studies. As a secondary choice, for computational ease, the blur size can be used. / Ph. D.

This feasibility study examined the possibility of using an independent voice recognition system as the input device during a training delivery requirement. The intent was to determine whether the voice recognition system could be incorporated into a training delivery system designed to train students how to use the Communications Electronics Operating Instructions manual, a tool used for communicating over the radio network during military operations. This study showed how the voice recognition system worked in an integrated voice based delivery system for the purpose of delivering instruction. An added importance of the study was that the voice system was an independent speech recognition system. At the time this study was conducted, there did not exist a reasonably priced speech recognition system that interfaced with both graphics and authoring software which allowed any student to speak to the system without training the system to recognize the individual student's voice. This feature increased the usefulness and flexibility of the system. The methodology for this feasibility study was a development and evaluation model. This required a market analysis, development of the voice system and instructional course ware, testing the system using a sample population from the Armor School at Ft. Knox, Kentucky, and making required alterations. The data collection approach was multifaceted. There were surveys to be completed by each subject: a student profile survey, a pretest, a posttest, and an opinion survey about how well the instruction met expectations. Data was also collected concerning how often the recognition system recognized, did not recognize, or misrecognized the voice of each subject. The information gathered was analyzed to determine how well the voice recognition system performs in a training delivery application. The findings of this feasibility study indicated that an effective voice based training delivery system could be developed by integrating an IBM clone personal computer with a graphics board and supporting software, signal processing board and supporting software for audio output and input, and instructional authoring software. Training was delivered successfully since all students completed the course, 85% performed better on the posttest than on the pretest, and the mean gain scores more than satisfied the expected criterion for the training course. The misrecognition factor was 12%. An important finding of this study is that the misrecognition factor did not affect the students' opinion of how well the voice system operated or the students' learning gain. / Ed. D.

In this dissertation the question of whether or not a relative extension of number fields has a relative integral basis is considered. In Chapters 2 and 3 we use a criteria of Mann to determine when a cyclic quartic field or a pure quartic field has an integral basis over its quadratic subfield. In the final chapter we study the question: if the relative discriminant of an extension K / k is principal, where [K : k] = l such that l is an odd prime and k is either a quadratic or a normal quartic number field, does K / k have an integral basis? / Ph. D.

The additive-plus-multiplicative model, Y_ij = μ + α_i + β_j + ∑_p=1^kλ_pτ_piγ_pj, has been used to describe multiplicative interaction in an unreplicated experiment. Outlier effects often appear as interaction in a two-way analysis of variance with one observation per cell. I use this model in the same setting to study outliers. In data sets with significant interaction, one may be interested in determining whether the cause of the interaction is due to a true interaction, outliers or both. I develop a new technique which can show how outliers can be distinguished from interaction when there are simple outliers in a two-way table. Several examples illustrating the use of this model to describe outliers and interaction are presented. I briefly address the topics of leverage and influence. Leverage measures the impact a change in an observation has on fitted values, whereas influence evaluates the effect deleting an observation has on model estimates. I extend the leverage tables for an additive-plus-multiplicative model of rank 1 to a rank k model. Several examples studying the influence in a two-way nonreplicated table are given. / Ph. D.