VictorJuiz/thesis huggingface dataset:
Aryl hydrocarbon-mediated inhibition of osteogenesis, reversal by resveratrol, a novel aryl hydrocarbon receptor antagonist

Aryl hydrocarbon receptor ligands (AhR ligands) are environmental contaminants found in cigarette smoke and other sources of air pollution. The prototype is TCDD (2,3,7,8 tetrachlorodibenzo-p-dioxin). There is increasing evidence linking cigarette smoking to osteoporosis and periodontal disease, but the mechanism is not well understood. By using resveratrol (3,5,4' -trihydroxystilbene), a plant antifungal compound that we recently demonstrated to be a pure AhR antagonist, we investigated the effects of TCDD on osteogenesis, hypothesizing that TCDD would inhibit bone formation in bone forming cultures and that this inhibition would be antagonized by resveratrol. We used the chicken periosteal osteogenesis (CPO) model which forms bone in vitro in a pattern morphologically and biochemically similar to that seen in vivo. The effects of drugs on various stages of bone formation such as differentiation, matrix production and mineralization can be assessed. Thus, this system is useful for studying osteogenesis through the measurement of alkaline phosphatase (ALP) activity (bone call differentiation, and phosphate or calcium accumulation (mineralization). To confirm our findings, we also used a mammalian (rat) cell line that produces bone in vitro. (Abstract shortened by UMI.)
A standardized approach to determine the effect of thermocycling and long term storage on the shear bond strength of orthodontic brackets cemented to bovine enamel

In the 1980's, direct bonding became a routine clinical procedure. Current literature on the effects of thermocycling on bond strength is equivocal. This is largely due to a lack of a universally accepted standardized technique to examine the effects of thermocycling on orthodontic bond strength. As a result, differences in testing methodology between laboratories and investigators within the same laboratory make it difficult to directly compare data from thermocycling studies. The aims of this study were (1) to show that the testing method developed at the University of Toronto is independent of the investigator; (2) to determine the effect of thermocycling on the shear bond strength of orthodontic brackets bonded to bovine enamel; (3) to determine the effect of long term storage on the mean shear bond strength of orthodontic brackets bonded to bovine enamel; (4) to examine the bond failure interface in order to determine if a relationship exists between thermocycling and the location of the cement after debonding; (5) to examine the bond failure interface in order to determine if a relationship exists between long term storage and the location of the cement after debonding. (Abstract shortened by UMI.)
The role of soil in the external corrosion of cast-iron water mains in Toronto, Canada

External corrosion of a cast-iron water main is influenced by the soil which surrounds it. A soil's "corrosiveness" is affected by factors such as resistivity, pH and sulphate reducing bacteria. This study collected water main and soil samples from locations across Toronto. Of the collected pipe samples 73% had experienced external corrosion; indicating that deterioration due to external corrosion is a concern. Using the measured soil properties, a linear regression analysis was able to explain 41% of the variance in the maximum external pitting rate. Looking at the effect of the soil properties individually the observed maximum external pitting rate was found to correlate best with soil resistivity. This thesis also found that there may be limitations to the practical application of the AWWA soil corrosiveness system. Finally, the use of GIS's in maintaining and rehabilitating water distribution systems is presented and a spatial analysis of the data is conducted.
Characterization of novel F-box proteins in Saccharomyces cerevisiae

Through the evolutionarily conserved E1[right arrow]E2[right arrow]E3 enzymatic cascade, ubiquitin is sequentially ligated onto protein substrates, thereby targeting the substrates for proteasome-catalyzed degradation. The SCF class of substrate-recognizing E3 enzymes is composed of Skp1, Cdc53/cullin, Rbx1, and an F-box protein. The F-box motif imparts the ability to bind Skp1. Through additional protein-protein interaction domains, different F-box proteins recruit specific substrates for ubiquitination. Of the many unknown F-box proteins identifiable in sequence databases, several were chosen to characterize in yeast: 'YJL204c' functions in a cold-sensitive pathway; 'YLR368w' generates petite cells when deleted which causes a sporulation defect; 'YOR080w ' mutants exhibit a G2/M cell cycle delay, are sensitive to overexpression of C1b5, and are prone to chromosome loss. Both Y1r368w and Yor08Ow form conventional SCF complexes, whereas Yj1204c associates with Skpl but probably not Cdc53. These biochemical and genetic data intimate diverse roles for F-box proteins in cellular regulation.
Corporate sponsorship and secondary school athletics

As financial constraints for public education across North America tighten, schools must look for creative ways to raise money to support school athletic programs. The purpose of this study was to examine the emerging role of selected companies in the Greater Toronto Area in the sponsorship of secondary school extra-curricular athletic programs. The study consists of five focal areas including: the corporate interest level for sponsorship, company motives for sponsorship, corporate decision-making with regard to sponsorship, soliciting corporate sponsorship and the expected nature of corporate sponsorship of secondary school athletic programs. For this study, questionnaires were mailed to 50 companies in the Greater Toronto Area. Thirty of these companies were considered to be large in size and 20 were considered small in size. The overall response rate was 60%. Companies were randomly selected from business directories as well as from personal business contacts of the author. As budgetary constraints tighten, it appears as though corporate involvement in schools will continue to become more prevalent. With proper regulation, this increase involvement has the potential to greatly benefit secondary school student-athletes across Ontario. (Abstract shortened by UMI.)
Prospective follow-up of infants exposed to 5-aminosalicylic acid containing drugs through maternal milk

The aim of this prospective cohort study was to estimate the risk of the adverse effects in infants breastfed by mothers receiving 5-ASA-containing drugs while lactating. We conducted telephone interviews with 121 women exposed to the drugs while lactating and 121 controls. The mean age for the exposed infants at the time of follow-up was 22 $\pm$ 20 months while the mean age for the non-exposed infants at the time of follow-up was 21 $\pm$ 18 months. Most of the exposed group had been taking the medication long term at least throughout the pregnancy. Based on maternal reports there were 14 (12%) clinical events in the infants of the exposed group and 13 (11%) in the control group (p = 0.4). The profile of clinical events in the infants were similar in the two groups and often were explained by other causes. The results of this study suggest that 5-ASA-containing compounds do not pose a significant risk to breastfed infants.
Characterization of the endogenous receptor and structure/function relationship of glucagon-like peptide-2

The effects of the 33 amino acid peptide hormone glucagon-like peptide-2 (GLP-2) on the induction of growth in the rodent intestine have been well characterized. The location and signaling pathways of the endogenous GLP-2 receptor (GLP-2R), as well as the structure/function relationship between the peptide and GLP-2R are currently unknown. Based on the fact that the proliferative effects of GLP-2 are intestine-specific, and on the homology between the GLP-2R and related receptors, we hypothesized that the endogenous GLP-2R was located in the intestinal mucosa and that it was coupled to cAMP production. We also hypothesized that the sequence of GLP-2 is important to its structure/function. We report that the endogenous GLP-2R is located in the mucosal compartment of the rat small intestine and that it is coupled to the cAMP pathway. To address the nature of the GLP-2 structure/function relationship, 55 analogs of GLP-2 were used for receptor binding and activation analyses on cells stably transfected with the rat GLP-2R. Although various analogs decreased the efficacy of GLP-2R activation, only [Gly2, Ala16], and [Pro2] GLP-2 were able to significantly increase receptor activation. In conclusion, the results presented here identify a physiological location of and second messenger for the endogenous rat GLP-2R, and demonstrate that single amino acid substitutions within GLP-2 confer significant changes in the structure/function relationship between GLP-2 and its receptor.
Parents as tutors of their own children, effects of a training program on children's achievement and confidence of parents

A study involving 85 parents and their elementary school children was conducted to determine the effect of a training program on parents' tutoring effectiveness as measured by their children's school achievement and the self-confidence of parents themselves. The results of this 16-week training provided dramatic and conclusive evidence of the effectiveness of extramural tutoring when parents are systematically trained to do so. The effects of such tutoring upon children's learning outcomes were superior to unsupervised parent tutoring and also more effective than small-group special education instruction in enhancing children's academic skills. Furthermore, parents' self-confidence significantly increased as a consequence of the training provided. The findings were examined in light of Bloom's (1984) 2-sigma postulate and against specific learning and motivational theories. The conclusions arrived at through this view into the black box of parent tutoring suggested a more explicit and concentrated inspection by future research on the content and quality of parent-child interactions as opposed to the traditional surface-structure preoccupations. This is a necessary step if the prevailing uncertainties in this focus are to be resolved. This research will be of benefit to both theorists and instructors of parent tutoring programs, and it will convey a clear message to parents who wish to help their children with schoolwork at home, that with informed support and guidance, effective extramural tutoring is well within their grasp.
Sharpening to focus on the urban landscape, approaches in landscape analysis

This study will explore a variety of analytical techniques in landscape analysis found within the sub-fields of historical and cultural geography. Elements within these approaches will be blended together to create a new methodology to analyse the urban landscape. This new analytical technique will be outlined and then applied to a section of the commercial core of Washington D.C. Reasons will be ascertained for the creation of Washington's contemporary urban distinctiveness. An argument will be made that the recent and on-going patterns of change in the form of downtown Washington, including the construction of 'mega-blocks,' are all features of 'postmodernity.' The work shall conclude by assessing the viability of the methodology in analysing Washington's urban landscape and its usefulness as an approach to the elucidation of urban landscapes generally. This study and methodology aim to create a new discourse between socio-cultural conditions, power relations and genetic urban history while linking these to our contemporary, 'postmodern' urban culture.
Microscopic Markov models for nonequilibrium reaction dynamics

In this thesis microscopic Markov models for nonequilibrium reaction dynamics are analysed. First, we consider a Markov chain model for a generic spatially-distributed chemical system. The evolution of such a model arises from a combination of local birth-death reaction events and random walks executed by the particles on a lattice. The dynamics of this Markov chain model is analysed by means of a perturbation expansion technique similar to the Chapman-Enskog development. The results of our perturbation theoretic analysis are confirmed by a comparison with the numerical simulations of the Willamowski-Rössler reaction-diffusion system and the quadratic autocatalysis system. Next, we turn to the analysis of Markov process models of complex nonequilibrium biochemical reaction pathways. Specifically, we consider two closely related processes involving DNA synthesis, the polymerase chain reaction (PCR) and ' in vitro' DNA replication. The models are based primarily on the assumption that the process of DNA synthesis occurs independently on each template DNA strand present in the system, which is valid for the realistic PCR and replication experiments. PCR models are used to simulate multicycle PCR runs and optimise the parameters of a given PCR run. With respect to 'in vitro' DNA replication, Markov models allow one to obtain important information on the synthesised DNA sequences (e.g. distribution of lengths, mismatch statistics, etc.) and identify the processes on molecular level which give rise to the outcome of a given DNA replication experiment.
Using open-ended tasks in grade twelve mathematics, an action research study

Senior high school mathematics education has traditionally focused on equipping students with methods and practices that allow them to solve single-answer questions or problems using learned mathematical notation. Courses such as grade twelve mathematics need to be directed and delivered with passion, skill, and in context with the learner's community. Thoughtful teaching, varied approaches, and fair assessment are central in building positive relationships with students. This study explores the incorporation of open-ended tasks as a means to improve the learning and teaching of mathematics. The effects of the planned use of open-ended tasks, especially journals and open-ended questions, are examined through two cycles of action research at the grade twelve level. Using thoughtfully prepared curriculum materials the following areas are investigated: students' understanding of mathematics, students' ability to do mathematics, course delivery, the learning environment, and students' attitudes. Finally, important suggestions for future study and curriculum development are posed.
Physicochemical studies of microbial flocs

This thesis investigates the influence of sludge retention time (SRT) on surface properties and interparticle interactions of sludge flocs, and the role of surface properties and interparticle interactions in bioflocculation, compaction and stability. Four laboratory-scale sequencing batch reactors (SBRs) were operated in parallel at different SRTs (4 to 20 days) for two years. Surface properties of sludge flocs were examined by a number of state-of-the-art techniques, including physicochemical extraction, chemical analyses and ultrafiltration of extracellular polymeric substances (EPS), contact angle measurement (hydrophobicity) and colloidal titration (surface charge). Interparticle interactions (electrostatic, ionic interactions and hydrogen bonds) and the stability of sludge flocs at different SRTs were evaluated in batch experiments by manipulating the water chemistry of the surrounding solutions. At all SRTs, proteins and carbohydrates were the dominant components of EPS, followed by a small amount of DNA. Acidic polysaccharides were not detected in the EPS. Molecular weights of proteins, carbohydrates and DNA in the EPS covered a broad range, from less than 1,000 daltons to more than 100,000 daltons. The majority (>85%) of EPS components had molecular weights larger than 10,000 daltons. The total amount of EPS was independent of the SRT. Sludge surfaces were more hydrophobic (a higher value of water contact angle) and less negatively charged at higher SRTs (16 and 20 days) than those at lower SRTs (4 and 9 days). The contact angle values were strongly correlated to the surface charge density. Changes in dissociation constants of sludge flocs in batch experiments indicated that electrostatic interactions were involved in disrupting the stability of sludge flocs, and ionic interactions and hydrogen bonds were present to compensate for the negative influence of electrostatic interactions on the stability of sludge flocs and to keep flocs together. Ionic interactions and hydrogen bonds were two dominant forces that maintained the stability of sludge flocs at lower SRTs; while other mechanisms, such as physical enmeshment and hydrophobic interactions, were likely more important than ionic interactions and hydrogen bonds in controlling the stability of sludge flocs at higher SRTs. In summary, the results from this study demonstrate that it is possible to operationally and chemically manipulate surface properties and interparticle interactions of sludge flocs for effective floc separation. A transition in floc surface properties was found to occur in the SRT range of 9 to 12 days. This transition in floc surface properties was linked to improved bioflocculation and a more stable floc structure. (Abstract shortened by UMI.)
Action and Advocacy, Alfred Fitzpatrick and the Early History of Frontier College

This thesis examines the early history of Frontier College, the oldest adult education organization in Canada. This examination draws upon social and educational influences on the organization's founder, Alfred Fitzpatrick. The thesis then documents and analyses the founding of the Reading Camp Association--later renamed Frontier College--and the development of the labourer-teacher model, both of which were designed to deliver educational services on the frontiers. It investigates Fitzpatrick's overall principles and the achievements of his organization, specifically its capacity both to challenge and uphold existing models of social and political power. Finally, the thesis draws conclusions about education, action and advocacy from a historical perspective.
Children's and parents' attitudes towards children's rights and perceptions of family relationships

The present study explored children's and parents' conceptions of nurturance and self-determination rights, perceptions of parenting styles, emotional autonomy, and family decision-making. Thirty-two fifth and sixth graders and their parents were presented a number of measures designed to assess attitudes towards children's rights, parental responsiveness and demandingness, parental involvement, emotional autonomy, and family decision-making. Generally, results showed that participants' attitudes towards nurturance rights were positively correlated with parental responsiveness, while their attitudes towards self-determination rights were positively related to opportunities for children to make decisions in the family. There were no significant differences between children's and parents' rights attitudes, with all participants highly endorsing nurturance rights. The findings are examined in terms of previous research and suggestions for future research are outlined.
No meaningless gesture, the measure and meaning of socio-economic rights in the New South African Constitution

One of the distinguishing features of the 1996 South African Constitution is its entrenchment of a set of extensive justiciable socio-economic rights in the Bill of Rights, which remains controversial and unusual for domestic constitutions today. This is because social rights are thought to be 'non-justiciable', as they necessitate budgetary allocation and policy decisions for their enforcement, which judges are not competent to make. For this reason, many believe the constitutional entrenchment of such rights to be nothing more than an empty gesture. I argue on the contrary that the constitutional entrenchment of socio-economic rights as independent human rights in the South African context has been valuable from historical, academic and political perspectives, and that the courts have shown the rights to have practical effect. Rather than meaningless gestures, socio-economic rights are valuable tools for the purposes of the elimination of social and economic disadvantage in the quest for social justice.
Genetic epidemiology of psoriatic arthritis

Psoriatic arthritis (PsA) is an inflammatory joint disease associated with psoriasis. The etiology of PsA is multifactorial with compelling epidemiological and immunogenetic evidence to implicate a strong genetic predisposition. Therefore a positional cloning strategy offers a potential approach to elucidate the genetic basis of this complex trait. In this thesis, three studies were designed using a well characterized PsA population, in an attempt to minimize the genetic (locus) heterogeneity of PsA. This will help facilitate the prospects of identifying susceptibility regions for PsA. The first study compared the clinical and immunogenetic factors of sporadic versus familial PsA. We noted a markedly younger age of onset of psoriasis and inflammatory arthritis in the familial group. The second study further characterized the PsA phenotype by comparing the clinical and immunogenetic features of those with early versus late onset psoriasis. Early onset psoriasis in patients with PsA appeared to be a more homogenous subset of PsA exhibiting a stronger association with HLA antigens previously demonstrated to be associated with psoriasis and PsA. In the third study we compared the penetrance and expression of PsA in offspring of affected mother versus an affected father, in order to determine whether a parent of origin effects exists at the phenotypic level in PsA. We demonstrated an excess paternal transmission in PsA. Defining a more homogeneous subset of PsA and postulating a non-Mendelian mode of transmission will likely assist in the fine mapping and ultimate cloning of susceptibility loci for PsA.