VictorJuiz/thesis huggingface dataset:
Inhibitory Control of Muscle Activity in Sleep
Keywords: sleep
motoneuron
glycine
GABA

In this thesis, I examined the inhibitory control of REM sleep motor activity using both a pharmacological rat model and a genetic mouse model. I characterized the role for GABA and glycine in mediating the REM-specific suppression of muscle activity as well as their involvement in regulating the phasic muscle twitches that punctuate this atonia. Based on four specific research objectives, the following conclusions were drawn: 1. REM atonia is not directly mediated by glycinergic or GABAA-mediated inhibition. These data refute the prevailing hypothesis that REM atonia is caused by glycinergic inhibition. These receptors are, however, important in the regulation of phasic muscle twitch activity. 2. GABAB receptors can modulate REM atonia but only when acting in concert with GABAA and glycine receptors. Blockade of all three receptor types results in a partial reversal of REM atonia, suggesting a functional interaction is occurring between these receptors during REM sleep. 3. The phasic glycinergic/GABAA-mediated inhibitory drive present in REM sleep regulates the temporal pattern of phasic twitch activity that is seen across this state. I hypothesize that this progressively decreasing inhibitory input counteracts a gradually increasing excitatory input to shape the temporal distribution of muscle twitches across REM sleep. 4. A loss of normal inhibitory function may play a causal role in the pathology of REM sleep behaviour disorder (RBD), the sleep disorder characterized by excessive motor activity in REM sleep.
Regulation of Early T-cell Development and Commitment by HEB
Keywords: T-cell development
hematopoiesis
E-proteins
HEB
thymus
TCRb-selection

Early T-cell development is regulated by a complex interplay between transcription factors and developmental cues which ensure that functional T-cells are produced within the thymus. Early thymocytes integrate these signals in a step-wise fashion that progressively restricts their lineage potential as they transition through the early stages of T-cell development. Gene knockout studies have shown that the E-protein transcription factor HEB is required for normal thymocyte development. Furthermore, many additional key regulators such as Notch1 have been identified, but the connections among them and their specific roles in early T-cell development have not been well established. In this thesis, I set out to determine the specific roles of HEB at the beta-selection checkpoint and to establish connections between HEB and the key regulators within the gene regulatory network that orchestrates early T-cell development. To facilitate these studies, I generated a series of new mouse models including HEBAlt transgenic mice that express a short form of HEB called HEBAlt, which enabled me to answer specific questions and examine rare populations. First, my studies of HEB-/- mice allowed me to identify an early block in T-cell development, which was alleviated upon the addition of an HEBAlt transgene. Furthermore, I identified pTa and CD3e signalling as specific targets of HEBAlt during -selection. Second, my studies on HEB-/- mice revealed that they have a defect in T-cell commitment, with compromised Notch1 function and a tendency to become DN1-like cells. Moreover, the DN1-like cells could be induced to differentiate into thymic NK cells, revealing a role for HEB in the T/NK cell lineage decision. This study has revealed a new set of interactions among HEB, Notch1, and GATA3 that regulate the T-cell fate choice in developing thymocytes. Unexpectedly, my studies have also provided evidence for a role of HEBAlt in lymphomagenesis, highlighting the strict regulation of E-protein function that is necessary to ensure normal T-cell development.
Criminal Law and the Development of the Assizes of the Crusader Kingdom of Jerusalem in the Twelfth Century
Keywords: crusades
Kingdom of Jerusalem
medieval law

The legal treatises of the Kingdom of Jerusalem were written in the thirteenth century, when most of the kingdom had been re-conquered by the Muslims. There are no treatises from the twelfth century, when the kingdom was at its height. The thirteenth-century jurists claimed that the kingdom had always had written laws, but they may have been making this up for political purposes. The treatises also discuss issues important to the noble class of which the jurists were a part: property rights and the feudal services owed to the king, as well as the proper way to plead their cases in court. But what do they say about criminal law, and laws for the lower classes? How were crimes tried and punished in the twelfth century, and did this differ from the laws recorded in the thirteenth century? Chapter one deals with the different treatises, and their claim that there was a set of laws called “Letres dou Sepulcre” in the twelfth century. The most important of the treatises for criminal law, the assizes of the burgess court, is examined in detail. Chapter two looks at the small number of laws that survive from the twelfth century, in charters, the canons of the Council of Nablus, and the chronicle of William of Tyre. Chapter three is a study of other descriptions of crusader law in the twelfth century, including those by Christian and Muslim pilgrims, and especially the observations of Usama ibn Munqidh. These accounts are tied together by the common theme of theft and the ways that thieves could be punished. Chapter four deals with cases mentioned by thirteenth-century sources, including theft, assault, and prostitution, but especially cases that led to trials by battle. The usefulness of such trials for dating some of the laws is also examined. The conclusion demonstrates that certain parts of the assizes relating to criminal law must have already existed in the twelfth century, and offers some tentative ideas about the specific origin of the laws. Avenues for future research are also introduced.
Understanding Maternal Sensitivity: Early Adversity, Arginine Vasopressin 1a Receptor Gene and Gene-environment Interplay
Keywords: Early adversity
Maternal sensitivity
Gene environment interplay
Vasopressin

The purpose of these studies was to examine mediation and moderation processes for the influence of early adversity and current stressful circumstances on maternal sensitivity. Evidence of mediation was found in Study 1 where maternal depression and mothers’ negative appraisal of their infant mediated the influence of early adversity and low family income on maternal sensitivity. Study 1 also examined the influence of the neighborhood. A moderate-mediation model was tested where the mediating influence afore-stated was hypothesized to vary across levels of neighborhood quality. Partial evidence of moderation was found. In the context of a high quality neighborhood, mothers’ early adversity was not associated with maternal depression. Across levels of neighborhood quality, complex relationships emerged between the variables low family income, maternal depression and mothers’ appraisal of infant temperament. In a context of low neighborhood quality, there was no evidence of a direct association between low family income and maternal sensitivity, rather, low family income operated indirectly through maternal depression. In a context of high neighborhood quality, there was evidence for a direct and indirect association between low family income and maternal sensitivity. Study 2 examined associations between variation in the Arginine Vasopressin 1a receptor gene (AVPR1a) and maternal sensitivity, and whether variation in this gene moderated the influence of mothers’ early adversity on sensitivity. Mothers homozygous for the long alleles of the RS3 microsatellite were significantly less sensitive than mothers heterozygous for the long alleles and those homozygous for the short alleles. Homozygosity for the RS3 long alleles moderated the influence of mothers’ early adversity on their sensitivity; the influence of early adversity on maternal sensitivity was most pronounced for mothers with the RS3 long/long genotype. These results suggest that variation in the AVPR1a gene may be important not only for human maternal behavior, but also for stress reactivity.
Monolithic Integration of Active and Second-order Nonlinear Functionality in Bragg Reflection Waveguides
Keywords: Bragg reflection waveguides
Nonlinear optics
Diode lasers
Semiconductor waveguides

This thesis explored the theory, design, fabrication and characterization of AlGaAs Bragg reflection waveguides (BRW) towards the goal of a platform for monolithic integration of active and optically nonlinear devices. Through integration of a diode laser and nonlinear phase-matched cavity, the possibility of on-chip nonlinear frequency generation was explored. Such integrated devices would be highly useful as a robust, alignment free, small footprint and electrically injected alternative to bulk optic systems. A theoretical framework for modal analysis of arbitrary 1-D photonic crystal defect waveguides is developed. This method relies on the transverse resonance condition. It is then demonstrated in the context of several types of Bragg reflection waveguides. The framework is then extended to phase-match second-order nonlinearities and incorporating quantum-wells for diode lasers. Experiments within a slab and ridge waveguide demonstrated phase-matched Type-I second harmonic generation at fundamental wavelength of 1587 and 1600 nm, respectively; a first for this type of waveguide. For the slab waveguide, conversion efficiency was 0.1 %/W. In the more strongly confined ridge waveguides, efficiency increased to 8.6 %/W owing to the increased intensity. The normalized conversion efficiency was estimated to be at 600 %/Wcm^2. Diode lasers emitting at 980 nm in the BRW mode were also fabricated. Verification of the Bragg mode was performed through imaging the near- field of the mode. Propagation loss of this type of mode was measured directly for the first time at 14 cm^-1. The lasers were found to be very insensitive with characteristic temperature at 215 K. Two designs incorporating both laser and phase-matched nonlinearity within the same cavity were fabricated, for degenerate and non-degenerate down-conversion. Though the lasers were sub-optimal, a parametric fluorescence signal was readily detected. Fluorescence power as high as 4 nW for the degenerate design and 5 nW for the non-degenerate design were detected. The conversion efficiency was 4176 %/Wcm^2 and 874 %/Wcm^2, respectively. Neither design was found to emit near the design wavelength. In general, the signal is between 1600-1800 nm and the idler is between 2200-2400 nm. Improvements in laser performance are expected to drastically increase the conversion efficiency.
Health Management in the Age of the Internet
Keywords: internet
social support
health management
actor network theory
doctor patient relationship
healthism

This study examines the way people use online resources within their personal healthcare practices to better understand how individuals manage their health issues in the age of the Internet. It specifically addresses the extent to which the Internet is used as an information database and associated patterns of use, whether the Internet represents a source of support or enables a supportive encounter and the implications of using the Internet as part of the health management across relationships with medical professionals and oneself. Using a sequential mixed methods design, the data was gathered within a larger multidisciplinary research project conducted in East York, Ontario. An initial quantitative analysis of 350 surveys describes Internet usage. The qualitative analysis of the 86 follow-up interviews of people recounting their personal health management processes demonstrated the importance of social networks, subjective health status and Internet user-style. The facile ability to engage with health information is transforming definitions and experiences of health and relationships with medical professionals. Examining medical encounters mindful of the aspects of trust, power, knowledge and privilege reveals an evolution to the doctor-patient relationship brought about by both information and personal empowerment. Using the Internet reinforces primary relationships and points to the development of new relationships that are sought at moments of meaningful life events or circumstances. New types of connections are being built across the Internet based on shared experiences, health concerns and health identities. Applying Actor Network Theory furthers an understanding of how search engines and online resources can emerge as actors in health information seeking and health management processes. Internet use is now a part of everyday life and is no longer limited to affluent early adopters as the gaps between those with access diminish in urban Canada. While its use is becoming intrinsically linked to health management it is not a panacea for improving health outcomes. As the populations’ collective health knowledge increases, so does the presumption that health management is a personal imperative. This notion that the achievement of good health is an individual responsibility or the theory of Healthism, frames the interpretation of the large percentage of the sample indicating they are striving to become healthier. Social workers need to acknowledge the place of the Internet within its practice and to balance the emphasis on individualized health management with the perspective that health outcomes reflect community mores. It is important for social workers to treat the Internet as a medium of relationships and for social workers to become knowledgeable about what these connections can provide in terms of support and information and what the limitations and risks of these relationships can be.
Modulation of Gamma Oscillatory Activity Through Repetitive Transcranial Magnetic Stimulation in Healthy Subjects and Patients with Schizophrenia
Keywords: Gamma Oscillations
Schizophrenia
rTMS
Working Memory

Background: Gamma oscillations (30-80 Hz) in the dorsolateral prefrontal cortex (DLPFC) are associated with working memory; a process involving the maintenance and manipulation of information on line (Baddeley, 1986). Gamma oscillations are supported by gamma-aminobutyric acid (GABA) inhibitory interneurons in the DLPFC. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive method in which to stimulate the cortex that has been shown to modify oscillations, cognition and GABAergic mechanisms. Patients with schizophrenia have severe deficits in working memory that may be related to impairments in GABAergic inhibitory neurotransmission underlying gamma oscillations in the DLPFC. Objective: First, to evaluate gamma oscillatory activity in patients with schizophrenia during working memory compared to healthy subjects. Second, to examine the effect of rTMS applied over the DLPFC on gamma oscillations generated during working memory in healthy subjects. Third, to examine the effect of rTMS applied to the DLPFC on gamma oscillations in patients with schizophrenia compared to healthy subjects. Hypotheses: First, it was hypothesized that patients with schizophrenia would exhibit an alteration in gamma oscillatory activity. Second, it was hypothesized that rTMS would be effective in enhancing gamma oscillations in healthy subjects. Third, it was hypothesized that rTMS would be effective in inhibiting gamma oscillations in patients with schizophrenia. Results: The first study found that patients with schizophrenia generate excessive gamma oscillations during working memory compared to healthy subjects. The second experiment found that rTMS over the DLPFC resulted in the potentiation of gamma oscillations in healthy subjects during working memory. The third experiment demonstrated that rTMS inhibited excessive gamma oscillations in patients with schizophrenia while an opposite effect was found in healthy subjects. Conclusions: rTMS applied over the DLPFC modulates frontal gamma oscillatory in healthy subjects and in patients with schizophrenia depending on baseline levels of activity, a finding that may ultimately translate into a better understanding of the mechanisms leading to cognitive improvement in this disorder.
Eliciting Dentists’ and Patients’ Preferences for the Treatment of Teeth with Apical Periodontitis
Keywords: Patient Preference
Decision Making
Dental Health Surveys
Apical Periodontitis
Dentistry
Dental Ethics

Background: Teeth affected by apical periodontitis (AP) that could be retained by root canal therapy (RCT) are increasingly being extracted and replaced with implant-supported crowns (ISC). Objectives: 1) To investigate preferences of dentists and patients towards retaining a tooth with AP using RCT versus its extraction followed by, no replacement, replacement with an ISC, or with a partial fixed or removable denture. 2) To investigate patients’ preferred role and dentists’ ethical responsibilities in decision-making. Methods: A mail-out survey (sent to: dental specialists, n=195, response rate=39%; patients, n=434, response rate=43%) and a web-based survey (general dentist sample, n=304, response rate =15%) were used to collect data. Statistical bivariate and multivariate analyses were undertaken with P set at < 0.05 with Bonferroni adjustment as necessary. Results: RCT or ISC were the most selected treatment choices for dentists, while the preference for RCT was reduced for teeth treated previously with RCT. Dentists’ preferences were associated with their specialty as well as clinical experience in endodontics and/or implant dentistry. Patients’ stated general preference for saving teeth was associated with higher self-rated oral health, frequent dental check-ups, and higher socio-demographic factors. Those with higher education, regular dental visits and previous experience of RCT preferred to undergo RCT for future treatment in comparison to those who never experienced RCT. Patients preferred a collaborative role with their dentists in making treatment decisions and valued the retention of natural teeth very highly. They also felt that communication with and trust in their dentist was paramount. Conclusion: Dentists should establish rapport with patients in a milieu that values and respects the patients’ autonomy. By following the highest standards of evidence-based care, and transferring unbiased information on treatment options and associated risks/benefits, it is highly probable that dental care will be delivered in a more ethical manner than would otherwise be possible.
Spirit Wrestling: Identity Conflict and the Canadian "Doukhobor Problem," 1899-1999
Keywords: Doukhobor
Religion
Ethnicity
Minorities
Immigration
Identity
Collective Memory

At the end of the nineteenth century, Canada sought “desirable” immigrants to “settle” the Northwest. At the same time, nearly eight thousand members of the Dukhobori (commonly transliterated as “Doukhobors” and translated as “Spirit Wrestlers”) sought refuge from escalating religious persecution perpetrated by Russian church and state authorities. Initially, the Doukhobors’ immigration to Canada in 1899 seemed to satisfy the needs of host and newcomer alike. Both parties soon realized, however, that the Doukhobors’ transition would prove more difficult than anticipated. The Doukhobors’ collective memory of persecution negatively influenced their perception of state interventions in their private affairs. In addition, their expectation that they would be able to preserve their ethno-religious identity on their own terms clashed with Canadian expectations that they would soon integrate into the Canadian mainstream. This study focuses on the historical evolution of the “Doukhobor problem” in Russia and in Canada. It argues that the “problem,” commonly misunderstood by political and legal authorities as a law-and-order issue, was actually an extended identity struggle, both among Doukhobors of opposed factions, and between Doukhobors and state authorities in Russia and in Canada who insisted on conformity to social, economic, legal, and political “norms.” It uses the Doukhobors’ historical experience in Canada to showcase a wide spectrum of possible “newcomer” responses to the Canadian “host” society, drawing attention to subtleties which may be missed in the study of less extreme cases. Using orally articulated collective memory narratives and print journalism sources to access Doukhobor and Canadian identity perceptions, this study argues that newcomers’ impact on Canadian identity definitions predated the multicultural shift of the late 1960s and early 1970s. By pointing out the way in which immigrants such as the Doukhobors did, or did not, conform to (Anglo-) Canadian “norms” in public discourse, Canadians articulated their national identity perceptions in the early decades of the twentieth century. This study concludes that the “Doukhobor problem” could only be solved when the contested identity narratives and collective memories which were at the root of the Doukhobors’ discontent were publicly addressed in “truth and reconciliation” style symposia called in the 1970s and 1980s.
Hygrothemal Degradation of Toughened Adhesive Joints: The Characterization and Prediction of Fracture Properties
Keywords: toughened adhesives
Hygrothermal
Fracture
Degradation
Open-faced
Accelerated

The main objective of this work was to develop a framework to predict the fracture toughness degradation of highly toughened adhesive joints using fracture test data obtained by accelerated open-faced degradation method. First, the mixed-mode fracture resistance (R-curve) behavior of two rubber-toughened epoxy-aluminum adhesive systems was measured and could be fit in a bilinear R-curve model. Then, open-faced DCB (ODCB) specimens of the same adhesive systems were aged over a relatively wide range of temperature, relative humidity (RH) and time, dried and tested to characterize the irreversible evolution of the mixed-mode fracture R-curves. The R-curve bilinear model parameters of adhesive system 1 varied significantly with degradation while that of adhesive system 2 remained unchanged. The absorption and desorption of water in the adhesives cast wafers was measured gravimetrically. The absorption data were fitted to a new sequential dual Fickian (SDF) model while water desorption was modeled accurately using Fick’s law. A significant difference was observed between the amounts of retained water in the two adhesives after drying. An exposure index (EI) was defined as the integral of water concentration over time and calculated at all points in the ODCB and closed DCB joints. The fracture toughness of the closed joints was then predicted from these calculated EIs by making reference to fracture toughness data from the ODCB specimens degraded to various EI levels. To verify the predictions, fracture experiments and analyses were carried out for closed DCB joints. Good agreement was found between the predicted and experimentally measured fracture toughness values for the degraded closed DCB joints. Furthermore, the crack path and fracture surface characteristics were evaluated as a function of the degree of aging using optical profilometery. The unexpected crack path in the mixed-mode fracture of unaged open-faced DCB specimens was addressed. The results showed a strong relationship between fracture surface parameters and the critical strain energy release rate, Gcs, irrespective of the type of adhesive and exposure condition.