VictorJuiz/thesis huggingface dataset:
The effect of phosphor persistence on image quality in digital x-ray scanning systems

A digital x-ray scanning system offers several advantages over conventional film-screen systems. However, there are sources of image degradation resulting from the scanning motion. One type of scanning motion blur is due to the temporal response of the phosphor. This mechanism produces an asymmetrical blur, requiring the use of the complex optical transfer function (OTF) for correct characterization of image resolution. The luminescence response of eight phosphors was measured under pulsed x-ray excitation. A weighted exponential model was used to represent the primary luminescence. The dominant luminescence lifetimes ranged from 2.7 $\mu$s for $\rm Gd\sb2O\sb2$S:Pr to 558 $\mu$s for $\rm Gd\sb2O\sb2$S:Tb. The long term response was also measured, monitoring significant increases in a slow form of luminescence known as afterglow. Afterglow was modeled by an inverse power law equation. Afterglow was found to be strong in at least two of the phosphors studied (ZnCdS:Ag and YTaO$\sb4$:Tm). In selecting a phosphor for a scanning system, it must satisfy several criteria, including a fast temporal response. Thus, a phosphor like $\rm Gd\sb2O\sb2$S:Tb, which has a slow luminescence, but otherwise excellent imaging properties, may not be as useful as a more rapid phosphor like CsI:Tl.
Molecular characterization of the hippurate hydrolase gene in hippurate hydrolase-negative Campylobacter jejuni isolates

Campylobacter jejuni is human entericbacterial pathogen. The present study examined the hippurate hydrolase gene from five different hippurate hydrolase-negative C. jejuni clinical isolates. Radiolabeled single strand conformational polymorphic (SSCP) assay detected the polymorphism in F7 and F8 regions of the hippurate hydrolase gene from five negative isolates compared with the respective regions of C. jejuni TGH9011 hipO. The promoter region and the remainder coding region revealed an identical PCR-SSCP patterns compared with the respective regions of C. jejuni TGH9011 in five negative isolates. The potential mutated regions were cloned and sequenced to determine the molecular nature of the mutations. Most of the mutations detected were silent in nature and they do not affect for amino acid alteration, except for valine (Val) at residue 250 altered to alanine (Ala). The Val-250 change was consistently present in all five negative isolates. Val-250 residue may play an important role in the hippurate hydrolase function.
Fixed identities and fluid lives, representation, regulation and possibilities of resistance in aids education

This project is an attempt to critically engage with pedagogical strategies which demand or envision a sense of stability, singularity and stasis in their subjects, and, more specifically, to come to some understanding of the way in which the pedagogical subject or learner is represented and regulated through AIDS education as it has unfolded in North America. The discussion is located around an analysis of the photographic images and texts employed in publicly distributed poster campaigns developed through AIDS education initiatives. Public educational initiatives around AIDS, regardless of the context of their initial production, have participated in a public discourse which has informed the constitution of subjects and identities, both in relation to AIDS and in relation to each other within the larger social. The production of AIDS posters which enjoy photographic images, and our reading practices and identifications in relation to them, are informed by both the historical emergence of photography as a medium and visual discourse which produces and locates bodies through representation, as well as other contemporary discourses which aim to construct what is known as AIDS. Processes of identification as well as those epidemiological, Judeo-Christian, and biomedical discourses having particular currency in the AIDS crisis are examined as constituting the conditions for the construction, normalization and regulation of subjects and bodies through AIDS education discourse. At the same time, it is precisely within these same processes of identification and disciplinary subject-formation that possibilities for resistance and clues as to the way in which AIDS education might play a crucial role in such a project of resistance are located.
When yes means no: An examination of the distinction between genuine consent and acquiescence

This thesis examines the boundaries which separate valid consent from invalid consent. It has two objectives: first, to show how the courts have responded to this central issue in various areas of law and, second, to extract from the case law a coherent test to be used to assess whether apparent consent constitutes valid consent. This paper addresses these goals in two main parts. Part One reviews various areas of law and shows how the courts have dealt with assessing whether consent is valid. This section examines the tests applied by the courts and isolates the theoretical bedrock that supports such analyses. Part Two relies upon the leading case law set out in Part One. It shows there is a fundamental meaning of consent which is universal to all areas of law. The case law demonstrates there is a consistent theoretical pillar upon which the meaning of consent rests. Part Two also identifies the essential elements of consent. This thesis contributes to existing law by pulling together leading cases in each area of law that analyzes consent and examining them as a whole. (Abstract shortened by UMI.)
Attempts to express the regulatory domain of protein kinase C-alpha in mammalian cell lines

The purpose of the current study was to express the R domain of human PKC$\alpha$ ($\alpha$R) in mouse Y1 adrenocortical tumor cells and in other cell lines in order to examine the potential ability of the R domain protein to dominantly and selectively inhibit PKC activity in intact mammalian cells. Three mammalian expression vectors encoding $\alpha$R were constructed: one that placed $\alpha$R under control of the mouse metallothionein-1 promoter, another with $\alpha$R under control of the human cytomegalovirus promoter, and a third that fused $\alpha$R with a polyhistidine and epitope tag also under control of the human cytomegalovirus promoter. These constructs were used in a number of transfection experiments. Northern blot analysis revealed that transfected cells successfully expressed the $\alpha$R transcript; however, the expression of the corresponding $\alpha$R protein product was not detected by Western blot analysis. When transfected cells were treated with a proteasome inhibitor, LLnL, 22 kDa and 30 kDa protein products were detected which appeared to accumulate upon longer exposure to LLnL. These products were not detected in cells that did not harbor an $\alpha$R expression vector nor were they detected in transfected cells without LLnL treatment. Since these proteins were of lower molecular weight than expected for $\alpha$R, they likely represented intermediates of $\alpha$R degradation. Together, these findings suggest that the $\alpha$R protein is unstable and unable to accumulate in mammalian cells, possibly because of rapid proteolytic degradation mediated by the ubiquitination-proteasome pathway.
The influence of attention at encoding on direct and indirect remembering

The relation between attention at encoding and direct (i.e., recognition) and indirect (i.e., rapid reading) remembering was investigated. In Experiments 1 and 2, a subtle attentional manipulation at study reduced direct but not indirect remembering. In Experiment 3, however, presenting two words simultaneously at study, with the instruction to attend to one (i.e., target) and to ignore the other (i.e., distracter), eliminated this dissociative effect of attention. Distracters were not remembered directly or indirectly, although targets were remembered well. Mere exposure is not sufficient to produce indirect remembering: Stimuli need to be attended. Experiments 4A, 4B, and 5 investigated factors that modulate the relation between attention at encoding and direct and indirect remembering. When stimuli are separated, ignoring an equally salient stimulus in favor of processing another stimulus may prevent even the minimal attentional requirements of indirect remembering from being met, let alone the more stringent requirements of direct remembering.
Tuberculosis infection in injection drug users in Toronto, prevalence and risk factors

Tuberculosis (TB) remains a global health problem. In Canada, TB is largely confined to high-risk groups. Injection drug users (IDUs) may be at increased risk of both acquiring TB infection and developing active disease. The primary objective of this study is to determine the prevalence of positive TB skin tests among IDUs in Toronto. A secondary objective is to determine the predictors of a positive TB test in this population. Of 167 eligible IDUs recruited through Toronto needle-exchange services, 155 or 92.8% returned for skin test interpretation; 48 or 31% (95% Cl 27.3, 38.3) were positive. Increasing age, birth outside of Canada and number of times in jail were predictive of a positive TB skin test. Although the sample studied has limitations, these results suggest a high prevalence of TB infection in this IDU population. The observed compliance with skin test interpretation indicates that successful TB screening can be achieved in drug-using populations.
The influence of grain boundary network structure on intergranular creep cavitation of OFHC copper

The prospect of structural failure, in proposed OFHC copper nuclear waste canisters, initiated by intergranular creep cavitation has prompted an investigation into the possibility of cavitation resistance enhancement through grain boundary engineering (GBE). In order to successfully implement GBE, the influence of the grain boundary network structure on creep cavitation must be ascertained. For this purpose, post-creep test characterization, using the electron backscatter diffraction technique, was performed on cavitated and non-cavitated grain boundary and triple junction structures. The implication of the findings were discussed in reference to the Coincident Site Lattice framework for grain boundaries and Bollmann's I-line/U-line model for triple junctions. Grain boundary characterization revealed that creep cavitation occurred primarily along a path of random boundaries. It was also determined that low angle ($\Sigma$ 1) and twin ($\Sigma$ 3) boundaries were the more cavitation resistant than random and other higher $\Sigma$ CSL ($\Sigma$ 5-29b) boundaries. The lack of observed cavitation selectivity between random and $\Sigma$ 5-29b boundaries was attributed to the fact that creep conditions might be too severe. This may also explain the lack of selectivity of U-lines as preferential sites for cavity nucleation observed in this thesis. The findings of this thesis, however, do illustrate that there is grain boundary structural influence on intergranular creep cavitation of OFHC copper.
Cytochrome P450 peroxidase/peroxygenase-dependent metabolic activation of xenobiotics

Cytochrome P450 (P450) peroxidase and peroxygenase activities have been well documented with microsomal enzymes and purified P450 preparations, however, the biological significance of these pathways in the bioactivation of xenobiotics and induction of oxidative stress in intact cells has not been demonstrated. The following summarizes our new findings regarding the role of P450 peroxidase/peroxygenase pathways in intact cells: (1) tert-butylhydroperoxide (tBHP) at non-toxic concentrations markedly enhanced up to 20 fold the cytotoxicity of various aromatic hydrocarbons and their phenolic metabolites towards isolated rat hepatocytes. The enhanced cytotoxicity was also accompanied by an increase in the hepatocyte O-demethylation of xenobiotics and xenobiotic reactive metabolites-GSH conjugates. An LC/MS analysis of the GSH conjugates identified hydroquinone:GSH and 4-methoxycatechol:GSH conjugates as the predominant adducts for 4-hydroxyanisole (4-HA). Pretreatment of hepatocytes with P450 inhibitors, e.g. phenylimidazole, prevented tBHP-enhanced 4-HA metabolism, GSH depletion and cytotoxicity. Hydroperoxides can therefore be used by intact cells to support the bioactivation of xenobiotics through the P450 peroxygenase system. (2) The naturally occurring hydroperoxide, hydrogen peroxide, was found to be particularly effective at supporting cytochrome P450 1A2-catalyzed activation of the heterocyclic aromatic amine, 2-amino-3-methylimidazo) 4,5-f) quinoline (IQ), to genotoxic metabolites. The addition of hydrogen peroxide or tBHP to rP4501A greatly enhanced the yield of histidine prototrophic (His$\sp+)$ revertants, which was inhibited by a-naphthoflavone, a P450 1A inhibitor. Hydrogen peroxide was the most effective peroxygenase cofactor, particularly with human P450 1A2-containing microsomes (hP4501A2). The hydroperoxide-supported activation of 1Q formed an adduct with 2$\sp\prime$-deoxyguanosine similar to that of the well characterized DNA adduct formed (in vivo or in vitro) by the P450-catalyzed bioactivation system. (3) Organic hydroperoxides are believed to be primarily bioactivated to cytotoxic radical species by non heme iron. However, various P450 inhibitors were found to prevent cumene hydroperoxide (CumOOH) metabolism and subsequent cytotoxic effects including antimycin-A resistant respiration, lipid peroxidation, iron mobilization, ATP depletion, and cell membrane disruption. These results suggest that P450 enzymes in hepatocytes bioactivate CumOOH to form reactive radical metabolites or oxidants that cause lipid peroxidation and cytotoxicity.
A PMOS transistor for a low-power 1 V CMOS process

Due to the growth of the battery powered electronics consumer market, the use of integrated circuits in low power applications has become the focus of intense work in the last few years. Developing a technology capable of operating at a low supply voltage is the most straightforward way to accommodate low power applications. A major hurdle in realizing a low voltage, sub-micron CMOS technology is the requirement of dual gate doping, n$\sp+$ for an n-channel device and p$\sp+$ for a p-channel device. Tailoring the PMOS transistor to a low voltage CMOS technology is the focus of this thesis. The PMOSFET requires special attention because of the process difficulties arising in fabricating a p-channel device with a p$\sp+$ poly gate. High frequency and quasi-static C-V tests on p$\sp+$ poly gates fabricated at various conditions were used to establish the fabrication conditions of a p-type gate on 200 A gate oxide without boron penetration into the channel or polydepletion of the gate. Surface channel PMOS devices compatible with 1 V applications were subsequently fabricated with a minimum $L\sb{eff}$ of 2.2 $\mu$m, a $V\sb{to}$ of $-$370 mV, an S of 83 mV/dec and a low off-state leakage current of 2.5 pA/$\mu$m. This work can easily be extended to submicron devices.
Perfectionism as it relates to achievement

The present research examined the relations of individual differences in perfectionism and academic achievement in school-aged-children. The moderating effects of affect and self-esteem on perfectionism and achievement were also examined. A sample of 223 students (90 males, 133 females) from regular, gifted, and arts programmes completed measures of self-oriented and socially-prescribed perfectionism, as well as measures of positive and negative affect, and perceived academic competence. Achievement scores were taken from the Canadian Achievement Test (CAT), which had been previously-administered. Correlational analyses revealed that the socially-prescribed perfectionism dimension was correlated with lower achievement scores. It was also found that the effects of perfectionism were domain-specific across programmes. Higher levels of negative affect were associated broadly with both perfectionism dimensions. There were few significant correlations involving self-oriented perfectionism and achievement, or both dimensions of perfectionism and academic self-esteem. Overall, the results suggest that academic achievement may be affected negatively by striving to please others who set perfectionistic standards.
Construction and functional characterization of a cDNA clone for the spliced variant of ß-galactosidase and further evidence that it encodes the elastin/laminin binding protein, EBP

The purpose of this study was to provide the conclusive evidence to the genetic origin of the elastin/laminin binding protein (EBP). Previous studies showed immunological, structural, and sequence homology between the enzymatically inactive alternatively spliced variant of human $\beta$-galactosidase (S-gal) and sheep EBP. In this study, the full length S-gal cDNA clone was constructed from two overlapping S-gal cDNA fragments. With this clone, in vitro transcription/translation was conducted and yielded a protein that reacted with anti-S-gal antibody and bound to both elastin and laminin. Subsequent S-gal transfections into mammalian COS-1 cells revealed increased production of a 67-kD protein that localized intracellularly and to the cell surface, and was extracted from cells lysates by an elastin affinity column. Moreover, the transfected cells showed increased adhesion to elastin, attesting to the cell surface distribution and functionality of the newly produced S-gal-encoded protein. Most important, similar transfection of EBP-deficient ductus arteriosus smooth muscle cells lead to an increase in their expression of EBP and enhanced their EBP-dependent elastic fiber assembly and adherence to elastin. These results provide further evidence as to the identity between the 67-kDa S-gal and the 67-kDa EBP.
Synthesis of trifluorovinyl ethers

Novel trifluorovinyl ethers (TFVEs, ROCF=CF$\sb2),$ where R is a functionalized oligo-ether, were synthesized by two methods. In the first method, thermolysis of trimethylsilyl 2-alkoxy-2,3,3,3-tetrafluoropropionate esters in the gas phase yielded TFVEs. Variable temperature $\sp{19}$F NMR spectroscopy of trimethylsilyl 2-alkoxy-2,3,3,3-tetrafluoropropionates suggests that these esters exist in an equilibrium between two structural conformations. In one conformation, there is intramolecular "interaction" of silicon with fluorine. The second is a random conformation. To some degree, this interaction may influence the outcome of the thermolysis reaction which is ultimately successful because of favorable reaction kinetics. In the second method, the TFVEs were synthesized by the reaction of a sodium alkoxide with tetrafluoroethylene (TFE). For alkoxides of limited solubility, the observed rate of reaction was determined to be rate-limited by the forward and reverse rates of solubility and the rate of reaction with TFE. Addition of 18-crown-6 was shown to significantly increase the rate of reaction.
From Fashion to Fitness? A Sociocultural Analysis of the Representation of Thinness within the Mass Media

The prevalence of eating disorders among young women has been called an epidemic within Western society (Brumberg, 1988). While there are a complex series of psychological, familiar and sociocultural elements at play in this development, the focus of this study was on the role of the mass media in presenting thinness as a socially constructed feminine ideal. The purpose of this thesis was to expand further the cultural definition of thinness by looking at the variations in its presentation within two categories of women's magazines: fashion and fitness. An exploration was undertaken of the process of consumerism and the structural linkage between advertisements and editorial content. This examination was filtered through my own in-depth personal relationship to eating pathology and my negotiation of thinness as an ideal construct. While thinness appears to be the current ideal image of beauty presented within this print medium, through diverse advertising strategies this image may be presented differently within various types of women's magazines. I argue that thinness is not a uni-dimensional construct and should not be examined as such within the eating disorder literature. It is important to expand research beyond a linear mode of causality between eating pathology and the media's promotion of a thin body image, and to acknowledge women as active participants in the negotiation of media imagery.
Soil-gas radon-222 anomalies in south central Ontario, Canada

Radon is a newly recognized environmental hazard, however, few studies have been conducted in Canada. Near-surface in-situ radon soil gas levels were measured at the eastern end of the Greater Toronto Area (GTA) of south central Ontario, Canada. Transects cross mapped surface lineaments (stream valleys) that coincide with a prominent Mid-Proterozoic shear zone known as the Central Metasedimentary Belt Boundary Zone (CMBBZ) that crosses the GTA. Overlying Paleozoic and glacial strata are extensively fractured. Anomalous high radon levels (up to 1000 pCi/L) are identified at each location and range from 2-6 times above background levels. Results of repeat measurements support the continued presence of these anomalies occurring at or adjacent to the same positions along each transect. It is likely that subsurface structures such as fractures, provide pathways for radon transport to the surface; work elsewhere has shown that high radon levels define fault boundaries. In light of these findings, hazardous or near-hazardous levels of radon may occur elsewhere across the GTA. Mapping fractures and related structures may provide a useful constraint on hazard identification.
Pixels and pigment, designing museum web sites that support art education

Museum Web sites are undergoing a period of rapid and ambitious expansion coupled with experiments in design. In the last several years a new body of literature and theory has been published bearing insight on many Web site design issues. This thesis asks whether a group of recommendations may be proposed, based upon the literature, and an analysis of several current museum Web sites, which can help to inform decisions faced by museum Web site designers. The result of this research proposes practical recommendations which focus on assisting in the design of Web sites that support the needs of art education. Discipline-Based Art Education (DBAE) is used in this thesis as the model through which learning in the arts is considered.
The institutions and processes of federalism and industrial policy in Canada

This thesis deals with considerations concerning federalism to facilitate the development and implementation of industrial policy. In the Canadian context, it is simply insufficient to speak of the latter in isolation of the former. The outlined theory of industrial policy, with criticisms noted, provide the context for the discussion on federalism. Part II examines the various processes and institutional variables of federalism and principles of intergovernmental action to facilitate such interaction. A more explicit and direct attempt is then made to discuss industrial policy and federalism by considering, in greater depth, some specific policy areas relevant to industrial policy. Institutions, including federalism and the way intergovernmentalism is structured tend to have important implications for the development and implementation of coherent and effective industrial policy, although achieving the optimal structure may not necessarily provide a solution, nor is obtaining such optimal structure necessarily possible under the prevailing circumstances.