VictorJuiz/thesis huggingface dataset:
Mechanoprotection, cytoskeletal adaptations of mechanical stresses

The specific role that the actin cytoskeleton plays in early mechanically-induced signal transduction events is unknown. The goals of this thesis were to develop an 'in vitro' model system that would allow the application of forces to extracellular matrix receptors through to actin, and to then characterize the role of actin in force-induced calcium ion fluxes. The force model uses collagen-coated magnetic beads that bind through integrin receptors and form adhesion complexes that include vinculm, talin and actin. A magnetic field is used to apply physiological levels of force to substrate-attached cells. With this model I found that the relative amounts of cortical F-actin in the vicinity of the bead exert a direct effect on the sensitivity of stretch-activated ion channels (SAC). Thus decreases in F-actin induced by cytochalasin D treatment lead to higher amplitude calcium ion influx during force application while increases in cortical F-actin induced by prolonged force applications (30 minutes), desensitized the SAC to further force applications. The mechanisms and consequences of force-induced actin accumulation on the cytoplasmic side of the cortical extracellular matrix adhesion sites were examined. Atomic force microscopy demonstrated that at the sites of actin accumulation there was a six-fold increase in local membrane rigidity. Cytoskeletal reorganization was dependent on force-induced kinases, one of which serine phosphorylated ABP-280, an actin crosslinking phosphoprotein. Co-localization of the serine phosphorylated ABP-280 and ß-actin to the matrix adhesion sites was demonstrated. Using kinase inhibitors that blocked force-induced ABP-280 serine phosphorylation, and a naturally occurring ABP-280 deficient cell line, I demonstrated that the serine-phosphorylated ABP-280 is essential for actin accumulation. The biological importance of this force-induced actin reorganization was demonstrated by a 2-fold increase in cell death in the ABP-deficient cells compared to ABP-expressing cells following force application. These studies suggest that ABP-280-dependent cytoskeletal reorganization enhances cell survival in mechanically active environments by stabilizing cytoplasmic Calcium homeostasis and preventing force-induced Membrane disruption. I have termed this cytoskeletal adaptation to physical force mechanoprotection.
Black women activists in Toronto from 1950 to 1990

This thesis explores the work and life of black women activists in Toronto from 1950-1989. In this thesis, I examine how black women are able to move from subject to radical subject. Further, I interrogate the nature of activism as defined by black women who are engaged in social change work. This study combines multiple theoretical approaches to understand the workings of power, discourse and race on black women activists. The research also is embedded within an Afrocentric feminist framework to explore notions of resistance and experience. I have found that within the American historiography on black women activists a connection is made between black women's activism and the social and educational advancement of black communities. The history of black women activists' work and their impact on black communities in Canada has not been adequately recorded. My study reveals through the oral testimony of black women activists that their social change work has improved social and political opportunities for black people In Toronto. Activism for black women is a process that emerges out of their everyday resistance to oppression. The findings of the study highlight the strategies that black women use in their communities to address social Inequities. Ideas of community and family were used by black women activists, in this study, as a site from which to challenge systems of oppression.
Group structuring effects on gender-specific discourse interactions within knowledge-building communities

One relatively recent educational paradigm which has great promise in ameliorating the scientific literacy crisis and the lack of girls choosing careers in science is social constructivism. The centrality of the role of discourse in social constructivist settings necessitates the consideration of differences in discourse styles between males and females. This study examines how structuring students in all-girls, mixed-gender and all-boys groups effects the level and type of discourse produced during face-to-face interactions. Girls in gender-specific groups demonstrated advanced levels of both social and cognitive development compared to the other groups. Students in this study also participated in electronic database conferencing. The discourse on the database produced evidence that girls who had difficulties during face-to-face discussions, made more contributions, displayed greater confidence and showed improvements in motivation. The implications of these findings in the restructuring efforts of science education are explored.
Brain G-proteins in drug dependence, a postmortem study

Substantial evidence implicates altered dopaminergic receptor and G protein-coupled cAMP signaling in the development of drug dependence. Chronic cocaine and morphine administration to rats reduces NACS GÃi levels, but the effects of these drugs on G protein levels in human brain have not been systematically studied. Accordingly, G-protein subunit immunolabelling was measured in NACS, putamen, amygdala, hippocampus, and occipital, temporal, frontal and cerebellar cortices from chronic cocaine (N = 12), heroin (N = 8), or methamphetamine (N = 12) users using Western blotting. GÃi1, and GÃi2 or GÃo were significantly lower (p < 0.05) in NACS from heroin (GÃi1, 47%; GÃi 2, 49%) and methamphetamine (GÃi1, 32%; GÃo, 18%) users compared to controls. No significant differences were found in other regions or in brain from the cocaine group. Findings of reduced NACS GÃi immunolabelling in heroin and methamphetamine suggests that chronic use of these drugs may increase cAMP signaling through disinhibition of GÃi-regulated signal transduction.
Enlightenment, art, and education, becoming fully human

In this thesis I argue that modern Western society has changed the practice of art and in so doing has thwarted its role as an important contributing element to the development of fully human beings; that is, persons with equally balanced faculties of thinking and feeling and all that these imply. Prior to the Renaissance, the practice of art was an integral feature in the life of the majority of the people in the West; an experience that allowed its participants to access their feelings and by bringing them into consciousness provided the opportunity for self-actualization. Subsequent to the Renaissance, art became subserviant to the causes of instrumental reason, a particular mindset likened to Weber's notion of 'Zweckrationalität'. An emphasis on developing such a limiting form of thinking reduced the role of the arts on many levels, stultifying in the process an aspect of natural human growth for those who ceased to "engage" in art. Such is the role of art that is reflected in our schools and communities. This thesis attempts to substantiate such claims by presenting a personal understanding of what it is that makes us fully human and, within that context, examine the role art played in the past and plays today in the West. My suggestion is that the reintegration of the practice of "authentic" art in the life of individuals and the community will help humanize our societies, its continuing absence dehumanize; and that the artistic experience, whatever form it takes, is a valid form of inquiry and perhaps the only way that may enable humans to illumine the self and educate the feelings. Towards the end of the dissertation, an argument is presented that suggests the role of art be rethought, reworked and reconsidered in the public school system; deliberations that are specifically located within my greatest sphere of teaching experience, the Early Total Immersion Program.
Psychological adjustment of children with learning disabilities, do friends make the difference?

The present study examined the psychological adjustment and peer relations of children with (n = 108), and without (n = 104) learning disabilities (LD) in grades 4 to 8. Loneliness, depressive symptoms, global self-worth and self-perception of social acceptance were the four aspects of psychological adjustment measured. The Loneliness and Social Dissatisfaction Scale, the Children's Depression Inventory and the Self-Perception Profile for Learning Disabled Students were administered. Peer acceptance and friendship were the two forms of peer relations measured. Results indicate that children with learning disabilities are less accepted by peers, and they are at greater risk for loneliness and depression than the children without LD. Peer relations differentiated children in terms of psychological adjustment. Children with low peer acceptance were lonelier and more depressed and reported lower self-perceived social acceptance (SA) and global self-worth (GSW) when compared to children with average to high peer acceptance. Children with LD who had reciprocated school friends reported higher global self-worth than the children with LD who did not have reciprocated school friends. Children with two or more reciprocated and/or corroborated friends reported less loneliness and higher self-perceived social acceptance than children with less than two reciprocated and/or corroborated friends. Children who nominated five or more friends also reported higher self-perceived social acceptance than children who nominated fewer than five friends. The results demonstrated that friendship is a protective factor for children with and without LD, but it does not act as a buffer against the effects of low peer acceptance.
The development of novel thiol reagents for probing ion channel structure

Thiol reagents are designed to react with cysteine residues within ion channel proteins. In Part I, a novel thiol reagent, 2-(methylthiosulfonate)ethyl-' N'-('N,N'-dimethylaminoethyl)carbamate (MTSAC), was characterized when linked to the simple ion channel, gramicidin. MTSAC-treated channels showed a pattern of steps in the current recordings on the timescale of the carbamate bond isomerization; the size of the steps was sensitive to the location of the thiol-reactive site in relation to the channel entrance. MTSAC may be useful for establishing proximity to the pore in studies of ion channel protein structure. In the Part II, the synthesis of a group of lidocaine analogs was accomplished. A thiol-reactive lidocaine analog could be used to probe region surrounding the local anesthetic binding site in cysteine mutants of sodium channels. A group of lidocaine analogs was synthesized, with 2, 3, and 4 carbons linking the amino nitrogen and the thiol-reactive group.
Community, adaptation, and the Vietnamese in Toronto

In the late 1970s, in the midst of the "Boat People" crisis, Canada began accepting large numbers of Vietnamese refugees. Vietnam continued as one of the leading sources of refugees and immigrants arriving in Canada up until the early 1990s. This study is intended to provide a comprehensive overview of the adaptation of Vietnamese-origin individuals in the Toronto area. The research findings are organized into two main sections with the intention of focusing attention upon the intrinsic contributions of both the Vietnamese (as individuals and also as members of social collectivities) as well as the institutional actors of the host society within the process of adaptation as it has occurred in the spatial setting of the Toronto area. The first half of the study is concerned with the internal dynamics of the Toronto Vietnamese aggregate. The demography of the population, the internal social structure of the "community", residential trajectories, the relationship between residence and institutional participation, and the functional significance of ethnic institutions in the lives of Vietnamese are topics of individual chapters. The latter half of the study is concerned with the relationships of the Vietnamese population with the institutions of the host society in Toronto. Chapters in this section address the insertion of the Vietnamese in the labour market, and the interactions between Vietnamese individuals and ethnic community organizations with the mainstream media and criminal justice representatives.
The effectiveness of outcome goals, learning goals, and self-talk training in improving an individual's team-playing behavior

This dissertation examined the relative effectiveness of behavioral outcome, learning, and do your best goals as well as self-talk training in improving an individual's team-playing behavior, as defined by behavioral observation scales completed by peers. Specifically, the dissertation consisted of two studies, a laboratory and a field experiment. The laboratory study (n = 50) consisted of a 3 (outcome goal, learning goal, do your best goal) x 2 (self-talk training, control) design. Behavioral outcome and learning goals resulted in higher self-efficacy than did urging people to 'do their best'. Behavioral outcome goals were superior to learning and 'do your best' goals in bringing about team-playing behavior. Self-talk had no effect on self-efficacy or team-playing behavior as the manipulation was not effective. The field experiment (n = 126) consisted of a 2 (behavioral outcome goal, do your best) by 2 (self-talk, control) design. Self-talk training was an effective method of increasing an individual's self-efficacy and team-playing behavior when the individual was exposed to multiple self-talk training sessions. The main effect for goals on team-playing behavior was marginally significant. Goals had no effect on self-efficacy.
The development and properties of biofilms in biofilters

A series of microbiological and analytical techniques were established and used to study changes in biofilm over time and determine the effects of a hydrophilic pollutant, methanol, versus a hydrophobic pollutant, Ã-pinene, on biofilm properties. Extracellular polymeric substances (EPS) were extracted from the biofilm and the levels of carbohydrates, protein, uronic acid, DNA and humic acids were measured. The major EPS component was found to be carbohydrate during the biofiltration of methanol, which dropped gradually as the biofilm aged. The most significant decline was seen when the pollutant was switched to Ã-pinene (&ap;80% reduction in carbon loading rate). Relative hydrophobicity and surface charge of the biofilm were also measured. The type of pollutant and substratum did have an affect on hydrophobicity, while the surface charge of the biofilm varied with age; where aging biofilm became less negative over time. Microscopic analysis of cell viability in the biofilm over the course of the experiment displayed no significant variations. The proportion of Gram-negative microbial cells temporarily increased when the pollutant was switched from methanol to Ã-pinene. Dissociation studies using a salt, surfactant or chaotropic agent to determine biofilm strength proved to disrupt certain forces that held biofilm together and to surfaces. The substratum, in most cases, was the major determinant in affecting biofilm strength (i.e., the mechanisms of adherence).
Instrumentation and functional analysis of the patient adjusted static elbow splint

A stiffening of the elbow joint after trauma or surgery often results in a limited range of motion of the affected joint. The stiffened elbow is often slow to respond to the rehabilitative process, and a substantial loss in productive work days may result. Studies have shown that long duration, low intensity stretching results in more permanent stretching and causes the least amount of trauma to the injured tissues. An alternative treatment regimen was developed that uses a patient adjusted static elbow splint to apply long duration, low intensity stretching. It has been identified that the treatment regimen could be further optimised if the actual load or torque applied to the joint could be captured and analysed. The development of the appropriate instrumentation and monitoring equipment required to capture and analyse the torque applied to extend the elbow joint is presented in this thesis.
The synthesis, structures, reactivity and polymerization behavior of boron- and sulfur-nitrogen-phosphorus heterocycles and highly strained chalcogen- and boron-bridged (1)ferrocenophanes

The investigation of the chemistry of the boratophosphazene N(PCl 2NMe)2BCl2 led to the first examples of borazine-phosphazene hybrid cations [N(PCl2NMe)2BCl]+, which possess planar rings, and are formally hybrids of two textbook classes of inorganic heterocycles. The skeletal replacement of a boron atom in an inorganic ring with a heteroelement has been discovered from the treatment of N(PCl 2NMe)2BCl2 with Ag[AsF6] or Ag[SbF 6]. This provides a novel approach to the synthesis of heterocycles containing As(V) and Sb(V) which are difficult to prepare via conventional routes. The thionylphosphazene cation [NSO(NPCl2)2] +, was synthesized as a highly reactive intermediate, which cleaves diethyl ether to yield the sulfur-ethoxy substituted species, NSO(OCH 2CH3)(NPCl2)2, and reacts with 1,2-dichloroethane to yield NSO(CH2CHCl2)(NPCl2)2. Treatment of NSOCl(NPCl2)2 with SbCl5 produces macrocycles, [NSOCl(NPCl2)2]n (n = 2-6); whereas the similar reaction with GaCl3 provides a new, convenient, ambient temperature route to poly(thionylphosphazene) [NSOCl(NPCl2) 2]n. These transformations presumably occur 'via' a cationic mechanism. The reactions of cyclic thionylphosphazenes NSOX(NPCl2) 2 (X = Cl or F) with three oxygen-based nucleophiles [NaOPh, NaOCH 2CF3 and NaOBu] were found to proceed regioselectively; first at phosphorus and secondly at sulfur. The substitution of the rings has been extended to the synthesis of new mixed substituent poly[(alkoxy/amino)thionylphosphazenes] which are useful in pressure sensing composite materials. The first examples of highly strained sulfur-, selenium- and boron-bridged [1]ferrocenophanes have been synthesized and the ring-tilts (>31°) are the largest for any known [1]ferrocenophane. Extended Hûckel MO calculations were performed and predicted a decrease in the HOMO-LUMO gap as the ring tilt increases from ferrocene to Fe([eta]-C5H4)2S. Thermal and anionic ROP of Fe([eta]-C5H3Me)2S yields the first soluble poly(ferrocenylsulfide).
The recasting of the Female Gothic in the novels of Margaret Atwood

This thesis analyzes the novels of Margaret Atwood through the use of the Gothic as a framework. Atwood's novels re-write and re-vision aspects of the Female Gothic, the American Gothic, and the Canadian Gothic in their depiction of the problems of female identity and self-definition, human evil, and the demands and expectations placed on women and men by contemporary society. In the Introduction I present a history of the Gothic as a genre, analyzing narrative themes and concepts originating in Horace Walpole's 'The Castle of Otranto', Ann Radcliffe's 'The Mysteries of Udolpho ', and Matthew Lewis's 'The Monk'. I will show how the Gothic evolved, after the genre collapsed as a force in its original form by 1930, in both the United States and Canada. The Gothic as found in North America uses national history and the actuality of the landscape to provoke and depict terror. In both Canada and the United States the Gothic is used as a vehicle to depict issues of alienation and the influence of the past in both national and personal terms. In the Introduction I will also present a working definition of the Female Gothic that will show how the sub-genre is not, as many contemporary feminist theories have maintained, a genre that expresses female self-loathing, but one that permits an active engagement with the problems of constructing the female self as an active speaking subject. Chapters One through Seven will analyze each of Atwood's novels published to date in detail. In each, Atwood's use of the Gothic tropes of imprisonment, confinement, haunting, and surveillance will be examined. Atwood's use and rewriting of the Gothic canon will also be considered. In the conclusion, I will present a brief analysis of 'Alias Grace', Atwood's most recent novel, and show how Atwood has rewritten the Gothic form to depict female anxieties and contemporary political abuses, and to examine questions of human evil and the relations between space and time.
Spatio-temporal dynamics of complex-periodic and chaotic systems

In this thesis we present a study of the spatial-temporal organization of spatially-distributed media with complex-periodic and chaotic dynamics. In particular we consider systems whose spatially inhomogeneous dynamics exhibits period-doubling bifurcations. The most important feature of these media is the presence of synchronization line defects across which the phase of the local oscillation changes by multiples of 2[pi]. Such line defects are shown to be necessary for the existence of spiral waves in complex-periodic media and all possible types of defect lines are classified for system with local period-2'n' oscillatory dynamics. The transition from complex-periodic to chaotic dynamics is considered in detail. Turbulent regimes characterized by spontaneous nucleation, proliferation and collision of defect lines are described. It is shown that transitions to line-defect turbulence are non-equilibrium phase transitions. Synchronization line defects are identified in systems with excitable dynamics. The formation of spiral waves broken by the presence of defect lines is shown for a prototypical system with super-normal excitability. The discussion of a recent experiment where such spirals were observed in the Belousov-Zhabotinsky reaction system is presented. Due to their general nature, the phenomena presented in this thesis are predicted to be observable in a wide range of spatially distributed systems.
Action Research in Science Education and the Implications on Teacher Professional Development, a Case Study of Computer Teachers' Concerns

This is an interpretive study of six teachers in an elementary school as they grapple with the implementation of computers into the curriculum. The study looks at traditional professional development models that have influenced classroom strategies. The six participants were teachers from one elementary school in Ontario. Their teaching experience ranged from four years to twenty five years. The teachers were interviewed, and completed a questionnaire on their existing knowledge of computers. The Action Research method was used to assist teachers to reflect on their teaching practice. Teachers also kept journals and created action plans for future implementation. The findings of the study indicated that the teachers felt they were motivated by other teachers during the Action Research project. They also realized the importance of reflection but found it difficult to do. This study offers insights into how teachers are experiencing the implementation of computers into the curriculum.