Gnathic changes after head and neck radiotherapy have not been thoroughly characterized radiographically. The objectives of this study are to characterize changes to the teeth and jaws on panoramic images following intensity modulated radiotherapy (IMRT), and to determine whether subject comorbidities and radiation dose affect these changes. This retrospective analysis reviews the charts and panoramic images of 126 head and neck cancer patients who received IMRT at Princess Margaret Hospital between January 1, 2005 and December 31, 2008. Of the 126 subjects, 75 (60%) showed changes on panoramic radiographs; 66 (88%) of which consisted of widened periodontal ligament spaces (WPLS). The median time to WPLS was 29 months after IMRT. Female sex and dose correlated with decreased time to WPLS. These results suggest that WPLS is a common radiographic sign following IMRT that may not require endodontic intervention as post-IMRT WPLS is unrelated to the pulpal status of the tooth.

Gnathic changes after head and neck radiotherapy have not been thoroughly characterized radiographically. The objectives of this study are to characterize changes to the teeth and jaws on panoramic images following intensity modulated radiotherapy (IMRT), and to determine whether subject comorbidities and radiation dose affect these changes. This retrospective analysis reviews the charts and panoramic images of 126 head and neck cancer patients who received IMRT at Princess Margaret Hospital between January 1, 2005 and December 31, 2008. Of the 126 subjects, 75 (60%) showed changes on panoramic radiographs; 66 (88%) of which consisted of widened periodontal ligament spaces (WPLS). The median time to WPLS was 29 months after IMRT. Female sex and dose correlated with decreased time to WPLS. These results suggest that WPLS is a common radiographic sign following IMRT that may not require endodontic intervention as post-IMRT WPLS is unrelated to the pulpal status of the tooth.

In this research project, structural aspects of monomeric NADP+-dependent isocitrate dehydrogenase from Corynebacterium glutamicum (CgIDH) are investigated together with site-directed mutagenesis and fluorescence spectroscopy studies. CgIDH, one of the enzymes of the Krebs cycle, catalyzes the decarboxylation of isocitrate into α-ketoglutarate, which in some bacteria and plants regulates the flow of carbon into either the Krebs cycle or the glyoxylate bypass depending on the available carbon source. The structure of CgIDH complexed with Mg2+ has been determined at 1.75 Å resolution using X-ray crystallography. In contrast to the closed conformation of published structures of monomeric NADP+-dependent IDH from <i> Azotobactor vinelandii </i> complexed with either isocitrate-Mn2+ or NADP+, the structure of CgIDH complexed with Mg2+ demonstrates the open conformation. The superimposed structure of CgIDH complexed with Mg2+ onto the structures of AvIDH complexes reveals that Domain II is rotated ~24° or ~35º, respectively, relative to Domain I when isocitrate-Mn2+ or NADP+ is bound, resulting in the closure of the active site between the two domains. Fluorescence spectroscopic studies support the proposal that the presence of isocitrate or NADP+ could mediate the conformational changes in CgIDH. <p>In addition, three CgIDH mutants (S130D, K253Q, and Y416T) were created based on the structural analysis and previous mutagenesis studies of homodimeric NADP+-dependent IDH. Both the specific activities and the fluorescence spectra of these CgIDH mutants elucidate the roles of these active site residues in CgIDH catalysis. It has been suggested that the conformational changes observed in the presence of the substrate(s) may regulate enzymatic activity in CgIDH, in contrast to homodimeric NADP+-dependent IDH in Escherichia coli, where the phosphorylation cycle controls activity. It is also presumed that both Lys253 and Tyr416 may play critical roles in CgIDH activity, as do the equivalent residues in homodimeric IDH from porcine heart mitochondria. Similar structural features and conformational changes among monomeric CgIDH and homodimeric NADP+-dependent IDH enzymes suggest the phylogenetic relationships among various monomeric and homodimeric NADP+-dependent IDH from different sources.

Successful adaptation to changes is of great importance to today’s workforce and for organizations. Built on the I-ADAPT theory (Ployhart & Bliese, 2006), this dissertation research explored the relationships among ability and personality factors, adaptability, and adaptive performance. Using a relatively simple skill acquisition task, the noun-pair lookup task, this research examined whether those relationships would be affected by the skill acquisition stages at which a change is introduced. As such, unexpected changes were introduced at different performance stages of the noun-pair lookup task. In one condition, participants experienced an unexpected change to the varied mapping (VM) version of the noun-pair lookup task at early stages of consistent mapping (CM) task learning. In the other condition, the change from the CM task to the VM task was introduced at late stages of the CM task learning. Two hundred and twenty five participants completed the noun-pair lookup task in one of two conditions. They also completed measures of two Big Five factors (openness to experience at the construct level and conscientiousness at the facet level), the I-ADAPT-M measure of adaptability, and tests of working memory capacity and perceptual speed. It was found that the timing of introducing a change did matter. Controlling for pre-change performance, participants had greater performance decrements when the change was introduced at late stages of the CM task practice than when it was introduced at early stages of the CM task practice. Ability factors and personality traits were found to be predictive of strategy choice in the CM task. There was no evidence of the moderating effect of the performance stage at which a change was introduced on the relationship between ability factors and adaptive performance. The mediation effect of adaptability on the relationship between ability and personality factors and adaptive performance was not supported. Adaptability as measured by I-ADAPT-M was also correlated with personality traits but not with ability factors or performance on the noun-pair lookup task. In conclusion, this dissertation showed the importance of making a clear distinction between adaptability and adaptive performance, and taking into consideration skill acquisition stages in task-related adaptive performance.

In this research project, structural aspects of monomeric NADP+-dependent isocitrate dehydrogenase from Corynebacterium glutamicum (CgIDH) are investigated together with site-directed mutagenesis and fluorescence spectroscopy studies. CgIDH, one of the enzymes of the Krebs cycle, catalyzes the decarboxylation of isocitrate into α-ketoglutarate, which in some bacteria and plants regulates the flow of carbon into either the Krebs cycle or the glyoxylate bypass depending on the available carbon source. The structure of CgIDH complexed with Mg2+ has been determined at 1.75 Å resolution using X-ray crystallography. In contrast to the closed conformation of published structures of monomeric NADP+-dependent IDH from <i> Azotobactor vinelandii </i> complexed with either isocitrate-Mn2+ or NADP+, the structure of CgIDH complexed with Mg2+ demonstrates the open conformation. The superimposed structure of CgIDH complexed with Mg2+ onto the structures of AvIDH complexes reveals that Domain II is rotated ~24° or ~35º, respectively, relative to Domain I when isocitrate-Mn2+ or NADP+ is bound, resulting in the closure of the active site between the two domains. Fluorescence spectroscopic studies support the proposal that the presence of isocitrate or NADP+ could mediate the conformational changes in CgIDH. <p>In addition, three CgIDH mutants (S130D, K253Q, and Y416T) were created based on the structural analysis and previous mutagenesis studies of homodimeric NADP+-dependent IDH. Both the specific activities and the fluorescence spectra of these CgIDH mutants elucidate the roles of these active site residues in CgIDH catalysis. It has been suggested that the conformational changes observed in the presence of the substrate(s) may regulate enzymatic activity in CgIDH, in contrast to homodimeric NADP+-dependent IDH in Escherichia coli, where the phosphorylation cycle controls activity. It is also presumed that both Lys253 and Tyr416 may play critical roles in CgIDH activity, as do the equivalent residues in homodimeric IDH from porcine heart mitochondria. Similar structural features and conformational changes among monomeric CgIDH and homodimeric NADP+-dependent IDH enzymes suggest the phylogenetic relationships among various monomeric and homodimeric NADP+-dependent IDH from different sources.

This dissertation utilizes the event study methodology from the modern theory of finance to examine corporate name changes (CNCs). Data sources include press releases and articles announcing CNCs compiled by Lexis Nexis, annual reports collected from the SEC File microfiche database compiled by Q-Data and the EDGAR database compiled online by Mergent, and the Center for Research on Stock Prices and COMPUSTAT compiled by Wharton Research Data Services. These data sources are used to answer three primary research questions. First, what is the effect of a CNC related to a change in corporate image, as opposed to a change in corporate entity (e.g., acquisition), on a firm’s stock price? Second, what is the effect of a major change versus a minor change to the corporate name during a CNC related to a change in corporate image? Third, what is the effect of a non-brand name altering CNC versus a brand name altering CNC on a firm’s stock price? This dissertation makes its primary contribution to the study of CNCs by finding that CNCs related to a change in corporate image will have a positive impact on stock price whereas CNCs related to a change in corporate entity will not. Moreover, it finds that major changes to the corporate name during CNCs related to a change in corporate image will have a positive impact on a firm’s stock price whereas minor changes to the corporate name during CNCs related to a change in corporate image will not. Finally, it is the first study to examine the effect of CNCs on firms’ brand names and finds that non-brand name altering CNCs related to a change in corporate image will have a positive impact on a firm’s stock price whereas brand name altering CNCs related to a change in corporate image will not.

Economic events may cause structural changes in markets. To know the effect of the economic event we should analyze the structural changes in the market demand and supply. The purpose of this dissertation is to analyze the effect of selected economic events on market demand and supply using econometric models. Structural changes can be modeled according to the types of changes. For an abrupt and instantaneous break, a dummy variable model can be used. For a smooth and gradual movement, proxy variables which represent the event can be applied, if we know the variables. If we don‟t know the appropriate proxy variables, a smooth transition regression model can be employed. The BSE (Bovine Spongiform Encephalopathy) outbreak in the U.S. in 2003 is assumed to make abrupt and instantaneous changes in Korean meat consumption. To analyze the effect on Korean meat consumption, the Korean demands of beef, pork, chicken, and U.S. beef are estimated using an LA/AIDS (Linear Approximate Almost Ideal Demand System) model with the dummy variable specifying the time before and after the BSE. From the results we can confirm that food safety concerns caused by the BSE case changed Korean meat consumption structure. Korean beef and U.S. beef became less elastic, and pork and chicken got more elastic to budget. Korean beef became less price elastic, but pork and U.S. beef got more price elastic. The changes of U.S. natural gas supply caused by technology development and depletion in reserves are analyzed using a smooth transition regression model. From the results, we can confirm that the productivity improvement by technology development is greater than the labor cost increase by depletion, but not greater than the capital cost increase by depletion in mid-2000s. The effects of posting the winning bid in a repeated Vickrey auction are examined using a proxy variable. By applying an unobserved effect Tobit model to the experimental auction done by Corrigan and Rousu (2006) for a candy bar, we can confirm that the changes of bidding behavior are significant, especially when the winning bid is high. By extracting the bid affiliation effects, we showed that true willingness to pay can be estimated.

Thesis (M. Sc.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on Dec. 2, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science, Department of Earth and Atmospheric Science, University of Alberta." Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 236-248).