VictorJuiz/thesis huggingface dataset:
Expression, purification and characterization of the LEC-rat N-terminal metal binding domain from Atp7b, an orthologue to ATP7B, a copper transporting P-type ATPase implicated in Wilson disease

Wilson disease is an autosomal disorder caused by mutations in the 'ATP7B' gene encoding a copper-transporting P-type ATPase, resulting in compromised copper transport across the trans-Golgi network and plasma membrane of hepatocytes. The Long Evans Cinnamon (LEC) rat is an established animal model for Wilson disease. As in all rats, the N-terminal copper-binding domain of the LEC rat atp7b protein (LEC-rCBD) contains 5 putative copper binding motifs (GMTCXXC), as compared to 6 in the human orthologue. Competition 65Zn-blot experiments with Cu(I) and Ag(I) have strongly implicated LEC-rCBD to display cooperativity, a phenomenon exclusive to these two metals and not observed among other transition metals examined. Near-UV Circular Dichroism (CD) spectra suggest secondary and tertiary structural changes in the protein with the gradual saturation of copper, the most significant structural transformation occurring between 2 and 3 moles copper per mole of LEC-rCBD. Far-UV CD demonstrates that Ag(I) induces similar structural deviations and that the addition of copper to a 1:5, protein:metal ratio is directly proportional to a decrease in LEC-rCBD disulfide bonds. These results together with those obtained from competition studies establish a model where LEC-rCBD undergoes specific metal dependent structural changes.
Picking up the thread, an oral history of the Latin American Women's Collective in Toronto, 1983-1990

This thesis deals with the existence and experiences of the Latin American Women's Collective (LAWC) in Toronto from 1983 to 1990. This (her)story comes into being through the voices of four women from the Collective. It is also shaped through the use of historical material and informed by critical race and feminist theory. This work examines issues of exclusion and racism that women from the Collective faced with other women's organizations, especially the "progressive" white women's movement as embodied in the International Women's Day Committee. It also discusses how exclusionary power relations were echoed within the internal dynamics of the Collective. And, it uncovers how LAWC provided a space where women could question their roles, share their concerns and do politics--a space that sustained deep friendships and a new concept of family that for a historical moment gave the participants a taste of what the future could be like.
Risk factors for hearing loss in adolescents

Many studies have shown that hearing in young adults today has worsened compared to standards (such as ISO 7029) and previously published studies. The exact reasons for this observed decline in hearing remains unknown. The purpose of this study was to determine absolute hearing thresholds in adolescents and collect information regarding possible risk factors for hearing loss. Pure-tone audiometric thresholds were measured at nine different frequencies from 0.25 to 10 kHz in each ear. Additionally, consonant recognition was assessed using the Four Alternative Auditory Feature (FAAF) test in quiet and in speech-spectrum noise. Hearing thresholds in the present study were compared to results from published studies in teenage subjects and young adults. Results from the FAAF test did not reveal any signs of hearing loss and no conclusive evidence was found to suggest hearing acuity in adolescents is better than in young adults in the conventional frequency range (0.25 to 8 kHz).
Fast measurements of blood flow using magnetic resonance

This thesis investigates the non-invasive measurement of blood flow in large arteries using magnetic resonance (MR). Functional information can be obtained from such measurements, including stenosis grade, tissue perfusion, and vessel-wall elasticity. Unfortunately, traditional MR measurements of blood flow are relatively slow, and must combine data acquired from different cardiac cycles. Measurement errors may be introduced by this procedure if the flow is not purely periodic (e.g., due to respiration or arrhythmia). A solution to this problem is to collect an independent flow measurement each heartbeat. This thesis develops MR methods for this purpose using volume-selective excitations with reduced spatial encoding, with the goal of measuring aortic stiffness from data collected in one heartbeat. This work is divided into three incremental stages. The first develops a method to track the one-dimensional (1D) displacement of an excited bolus of blood. Displacement is derived from the frequency of the MR signal, which changes as the bolus moves through a magnetic-field gradient. The second stage extends this work by exciting blood at multiple positions along the vessel, and recording their displacements simultaneously using rapid 1D projections. From these 1D measurements, an expression for the velocity spectrum of the blood is also derived. The influence of specific excitation profiles and velocity profiles on these measurements is explored. The final stage applies the measurement to pulsatile aortic flow. An algorithm that detects the onset of systolic flow at each vessel position is developed and used to measure the aortic pulse-wave velocity (PWV), a parameter related to vessel stiffness. Measurements of the PWV in a single heartbeat are presented. This thesis demonstrates that volume-localization can be used to obtain independent blood-flow measurements each heartbeat. This is significant because it enables measurement of blood motion despite potential beat-to-beat fluctuations in the flow. The research culminates in a non-invasive measurement of the pulse-wave velocity that could facilitate the study of vascular mechanics. Use of this tool could lead to a greater understanding of cardiovascular physiology, particularly the mechanism through which disease processes and therapeutic interventions affect the mechanical properties of the aortic wall.
Effect of GABARAP (GABA§A-receptor-associated protein) on the interaction between the dopamine D¦5 and GABA§A receptors

In January 2000, Liu 'et al'. described a direct interaction between the dopamine D5 receptor and the GABAA receptor and were able to narrow this interaction down to the C-terminal tail of the D5 dopamine receptor with the second intracellular loop (IL2) of the ã2 subunit of GABAA. In addition, Wang ' et al'. (1999) reported, by means of the yeast two-hybrid system with the ã2 subunit of the GABAA receptor as bait, the identification of a novel cellular protein, which they consequently named GABAA-receptor-associated protein (GABARAP). Since D5 receptor-mediated cAMP accumulation decreased in the presence of the ã2 subunit of GABAA, and GABARAP binds the same subunit, it was of interest to see what would happen functionally in the presence of GABARAP. The aim of this project was, therefore, to look at whether GABARAP interfered with the functional receptor cross-talk seen previously between D5 and GABAA. It was found that GABARAP hindered the direct binding of dopamine D 5 with GABAA receptors, thus interfering with the ligand-gated and G protein-coupled receptor cross-talk.
The relationship between the use of computer-based technologies and students' evoked concept images of mathematical functions

The use of technological tools to promote students' understanding of mathematical concepts is becoming a key element of contemporary mathematics education. The integration of these tools in the classroom has led to a branch of study into their effectiveness. This study examined the nature of students' concept images of functions and the association of certain such images with the use of specific technology-based tools, including graphing calculators and motion-detector probes. This study also examined the role of discourse in facilitating the development of students' concept images of functions. The results suggest that incidental use of computer-based technology, with minimal opportunities for rich discourse, limits the development of rich concept images of functions. It is not the use of technology per se that leads to growth in understanding of functions, but rather, the benefit stems from an interaction between the use of technology-based tools and engagement in specific types of discourse.
Role of technology in managing vulnerability to natural disasters, with case studies of volcanic disasters on non-industrialized islands

Technology is one tool used and misused for managing society's vulnerability to natural disasters. Many of the difficulties encountered result from neither technical problems nor the specific natural disaster event, but manifest because society errs in applying technology or in assessing the natural hazard's severity. This study examines, critiques, and suggests improvements in this area. One of the most challenging steps for an engineer is defining the design criteria which should be used to anticipate a system's response during a natural disaster, because the design load input from a natural disaster is difficult to predict and select properly. An examination of non-technological influences, preventive engineering, and relevant boundaries and scales illustrates how to prevent vulnerability to natural disasters. The concepts and models developed are applied to case studies of volcanic hazards on non-industrialized islands. The eruptions of Mount Pinatubo in the Philippines (initial eruption in 1991) and Soufriere Hills in Montserrat (initial eruption in 1995) are examined.
Branch plate-to-rectangular hollow structural section connections

In recent years, the use of rectangular Hollow Structural Sections (HSS) as columns has become increasingly popular. In many instances rectangular HSS column members are replacing customary I-section members due to their superior column performance. In turn, welded longitudinal branch plates that have been a traditional and convenient method for the connection of brace members and other attachments to I-section columns are now similarly used for rectangular HSS columns. The current design method, consisting of welding a branch plate parallel to the axis of the column has not been thoroughly investigated, especially for the effects of connection flexibility, of branch plate inclination angle and of axial compression load in the column. This represents a known omission in current HSS column connection design knowledge and published design specifications. Based on experimental testing of isolated connections, parametric non-linear Finite Element analysis and analytical yield line analysis, the strength and behaviour of longitudinal branch plate-to-rectangular HSS member connections have been determined. On the basis of this, design criteria are herein proposed. These recommendations have also been reported in technical literature and the recommendations are being incorporated into design specifications and guides for HSS connections. A conventional longitudinal branch plate-to-rectangular HSS member connection tends to cause excessive distortion of the HSS connecting face. Such a connection therefore results in a low, deformation limit state, design resistance. In an effort to reduce this inherent flexibility of longitudinal branch plate connections, stiffening plates or structural tees can be welded to the HSS connecting face. Also, a "through" branch plate connection that extends through both walls of the rectangular HSS member can be used to increase the strength of a standard longitudinal branch plate connection. These "alternative" connections represent the next generation in rectangular HSS connection design. Once again, based on experimental testing of such connections, non-linear Finite Element analysis, and analytical yield line analysis, the strength and behaviour of "alternative" branch plate-to-rectangular HSS member connections have been determined and modelled, resulting in published recommendations. This thesis develops comprehensive, rational, limit states design procedures and equations that encompass, and wherever possible consolidate the behaviour of, the multitude of branch plate-to-rectangular HSS member connection types that will now be available to designers.
An exploration of collaboration in an educational environment using computer-mediated communication

This study was intended to contribute to knowledge in the area of collaborative learning in the context of computer-mediated communication (CMC). In the present study, collaborative learning was explored in terms of students' interaction in their learning process. The primary purpose of this study was to examine relationships between language functions associated with the messages generated in the context of CMC and participants' interaction. Language function was defined as "ways we can use language to achieve a communicative purpose" (Olsen, 1992). The secondary purpose was to learn the extent that participants interact in the context of CMC. The third purpose was to explore the use of language functions in relation to teacher-student interactions. The subjects for this study were selected from students who participated in the "Knowledge Forum Knowledge Building Community Project" in 1999. It was a fifth- and sixth-grade classroom in an inner city elementary school in Toronto, Ontario. A measure of interaction was developed in this study. Along with other three indexes, this measure was applied for the analysis of the data--the entire corpus of electronic messages from the student mathematics and science course from September 1998 to April 1999. Results of this study indicated that participants (including teachers, students, researchers and scientists) were actively participating in collaborative learning in the context of CMC. Out of five language functions examined, three language functions used by participants in the context of CMC showed no relationship with participants' interaction. However, participants' use of 'giving explanation' and 'expressing disbelief' was positively associated with their interaction. One interesting finding of teacher-student interaction was that with teacher and helping adult involvement, participants were more likely than students alone to make suggestions. When scrutinizing the pattern of the use of language functions in first messages, it appeared that students' strategy was to ask a lot of information, while with teachers and helping adults engagement, participants used 'presenting opinion' most frequently. Educational implication of this study was discussed. In addition, recommendations for future research about collaborative learning in the context of CMC were made.
The production of protein isolates from hexane-defatted ground yellow mustard meal

A process for the production of high-quality yellow mustard protein isolates was developed. The process consists of the extraction of oil-free meal at pH 12, followed by ultrafiltration and diafiltration to remove glucosinolates, and then isoelectric precipitation at pH 4.75 to recover some 50% of the dissolved protein. The acid-soluble protein is concentrated by ultrafiltration and purified by diafiltration prior to recovery by freeze-drying. These steps complement one another to yield three products with good protein recovery. A precipitated protein isolate containing about 89% protein (Nx6.25), a soluble protein isolate containing 98% protein and a meal residue with 19% protein were obtained. The two isolates recovered about 66% of the nitrogen in the meal, and were low in glucosinolates, essentially free of phytates, light in colour, and mostly bland in taste. The process is simple and has good potential for commercial application.
Adaptation to Disability, Self-efficacy, and Perceptions of Independence in Older Adults with Chronic Obstructive Pulmonary Disease

This thesis extends understanding of the relationship between disability and independence in community-dwelling older adults with COPD. An interviewer-administered questionnaire was used to examine disability, adaptation, perceptions of independence, and self-efficacy in a sample of 50 older adults. Relationships between variables were investigated with correlation coefficients and odds ratios. Participants used a wide range of behavioral strategies to adapt to their disability including: limiting activities, optimizing performance, compensating for lost function, and obtaining help from others. The relative use of these adaptations, and their associations to self-efficacy and perceptions of independence, varied across five domains of activity: personal care, in-home mobility, household activities, community mobility, and valued activities. The relationship between disability and independence in older adults with COPD depends on the nature of the activity, and the vast array of adaptations available to those with mild chronic physical illness enables older adults to remain highly independent despite disability.
A contribution to the understanding of a PEM fuel cell transient model

The purpose of this thesis is to build a foundation from which a transient model of a proton exchange membrane (PEM) fuel cell (FC) can be constructed. The FC model was developed taking into consideration basic physical and mathematical laws that describe the electrochemical mechanisms that govern the performance of a proton exchange membrane fuel cell (PEMFC). Our modeling approach considers the charge distribution in the whole FC (including the electrodes). This information is required if one is to create a realistic transient model of a FC. This thesis takes into account the presence of two mobile charged species in the (PEM). These charges are responsible for shaping the variable charge distribution profile across the double layers and the membrane. Additionally, due to the very well known impossibility to measure the absolute potential (or inner potential) of a half-cell, the need for a reformulation of the reference voltage is presented, and constitutes one of the major findings of this thesis.
The time of our lives, learning from the time experiences of teachers and administrators during a period of educational reform

This research project documents teachers' and administrators' experiences, feelings and thoughts about time in their lives during a period of profound educational change. While issues related to time as a limited resource and a way of scheduling activities are investigated, the research study is also concerned with time in intensely political circumstances—when the development of policy and the implementation of that policy are shaped by time constraints. In particular, the research focuses on the way that time as subjective experience is or is not phenomenologically different for educators positioned differently within the schooling system. The stories of teachers and administrators are used to study the meaning of time in everyday situations—to show the pervasive way that time influences actions. Based on the premise that individuals render their everyday social world visible through the stories they tell, this research sets out to understand the perspectives and meanings of time in the lives of these educators. How time relates to personal feelings, values, relationships, the implementation of curriculum reform, intensification, and power relations in the context of contemporary organizational life are of particular interest. In this research study, I collected data through semi-structured interviews of about one hour's duration with twenty teachers. Analyses of these data provide rich descriptions illustrating teachers' experiences with time for an educational world in rapid transformation. Subsequently, I identified an opportunity sample of three educational administrators and I invited these individuals to participate in four one-hour in-depth interviews about temporal issues in education. The conversation-based interviews highlight lived experiences of time through narrative. The thesis captures the intensity and the implications of time in the lives of teachers and administrators. It describes the taken-for-granted actions involving time and helps to unravel the meaning of time for these educators in the context of significant and politically driven change. Implications for reconceptualizing time are also considered.
Analysis of the possible therapeutic use of CYP2A6 inhibition with methoxsalen in smoking cessation

Smokers smoke to adjust their nicotine concentrations within a desired range. Since CYP2A6 is responsible for most of nicotine's metabolism to cotinine, use of a CYP2A6 inhibitor such as methoxsalen could have important implications in smoking cessation therapy by decreasing nicotine clearance, thereby, decreasing the need to smoke. CYP2A6 inhibition may also improve nicotine replacement therapy (NRT) by increasing nicotine concentrations and decreasing variation. This study showed that in smokers taking methoxsalen for 2 weeks, nicotine and nicotine/CO concentrations increased by 25% and 31% respectively when compared to placebo, but there was no change in smoking amount. In a separate study, methoxsalen increased nicotine concentrations by 24% and 52% from placebo, in abstinent smokers using the 21mg/day nicotine patch and 4mg nicotine gum respectively, but there was no significant change in interindividual variation. These results suggest that increased nicotine concentrations produced through CYP2A6 inhibition may be useful in enhancing NRT.
An exploration of the socioeconomic status--health status gradient in Ontario, results from the 1990 and 1996 Ontario health surveys

Data from the 1990 and 1996 Ontario Health Surveys are used to model the association between SES (income and education) and health status (the Health Utilities Index, Self-rated Health Status and Activity Restriction) in 1990 and 1996. The associations are first examined for each year separately and then an interaction analysis is done to determine whether there was a change in the overall association over time. The study found a positive association between SES and health status--health status increased with increasing SES--overall and for most subgroups. Results of the interaction analysis varied among health status measures. Significant interaction was found between year, income and the HUI, indicating that the slope of the gradient in the HUI by income changed from 1990 to 1996. This is primarily due to a drop in HUI among those with low incomes, and may be related to the recession of 1991-93.
Hybrid imaging guidance system for biopsy of the breast

A novel system for obtaining biopsy samples of lesions detected using contrast-enhanced magnetic resonance imaging (MRI) is presented. Contrast-enhanced MRI is used to detect the lesion, while the real-time ultrasound information is used to monitor the progression of a biopsy needle into the lesion. By accurately registering these two imaging modalities, the high sensitivity of MRI and real-time imaging capabilities of ultrasound are combined to improve the accuracy of lesion biopsy. The accuracy of this system and implementation of the biopsy techniques in pre-clinical trials are presented in this thesis. Targeting experiments were performed to evaluate the accuracy of MR-guided needle positioning and US image registration. Tissue-equivalent phantom experiments were performed to test the accuracy of the system in a more realistic model of a lesion within breast tissue. It was determined that the addition of ultrasound to guide needle placement provided substantial benefit in accuracy over MR-guided biopsy alone.