VictorJuiz/thesis huggingface dataset:
Structural Investigation of Biological and Semiconductor Nanostructures with Nonlinear Multicontrast Microscopy

Physical and functional properties of advanced nano-composite materials and biological structures are determined by self-organized atoms and molecules into nanostructures and in turn by microscopic organization of the nanostructures into assemblies of higher structural complexity. Therefore, microscopes are indispensable tools for structural investigations at various levels of organization. In this work, novel nonlinear optical microscopy methods were developed to non-invasively study structural organization at the nanoscopic and microscopic levels. Atomic organization of semiconductor nanowires, molecular organization of amylose biocrystallites in starch granules, and microscopic organization of several photosynthetic organisms was elucidated. The structure of ZnSe nanowires, key components in many modern nanodevices, was investigated using polarization harmonic generation microscopy. Based on nonlinear optical properties of the different crystal lattices, zinc blende and wurtzite nanowires were differentiated, and the three-dimensional orientation of the zinc blende nanowires could be found. The structure of starch granules, a model biocrystal, important in food as well as health sciences, was also investigated using polarization harmonic microscopy. The study was combined with ab initio calculations using the crystal structures of amylose A and B, revealing that second harmonic signals originate from the hydroxide and hydrogen bonds in the starch granules. Visualization of several photosynthetic organisms including the green algae, Chlamydomonas reinhardtii, two species of cyanobacteria, Leptolyngbya sp. and Anabaena sp., aggregates of light-harvesting pigment-protein complexes as well as chloroplasts from green plants were also explored, revealing that future nonlinear microscopy applications could include structural studies of cell walls, the Chlamydomonas eyespot, and photosynthetic membranes. In this study, several nonlinear optical microscopy modalities were developed for quantitative structural investigations of nano and micro-sized architectures. Non-invasive extraction of crystallographic information in microscopic samples will have a number of potential benefits, for example, in clinical applications, allowing observations of disease states inside tissues without the need for biopsy. Industrial nanotechnology will benefit from fast determination of nanostructures with nonlinear microscopy that will improve quality of nanodevices.

Keywords: Nonlinear Optics
Laser Scanning Microscopy
Semiconductor Nanowires
Starch Biocrystals
Second Harmonic Generation
Third Harmonic Generation
Polarization Harmonic Microscopy
Imaging Photosynthetic Structures
Advisor: Barzda, Virginijus
Development, Characterization and Validation of Trastuzumab-Modified Gold Nanoparticles for Molecularly Targeted Radiosensitization of Breast Cance

The overexpression of the human epidermal growth factor receptor-2 (HER-2) in 20-25% of human breast cancers was investigated as a target for development of a gold nanoparticle (AuNP) based radiosensitizer for improving the efficacy of neoadjuvant X-radiation therapy of the disease. HER-2 targeted AuNPs were developed by covalently conjugating trastuzumab, a Health Canada approved monoclonal antibody for the treatment of HER-2-overexpressing breast cancer, to 30 nm AuNPs. Trastuzumab conjugated AuNPs were efficiently internalized by HER-2-overexpressing breast cancer cells (as assessed by darkfield microscopy and transmission electron microscopy) and increased DNA damage from X-radiation in these cells by more than 5-fold. To optimize delivery of AuNPs to HER-2-overexpressing tumors, high resolution microSPECT/CT imaging was used to track the in vivo fate of 111In-labelled non-targeted and HER-2 targeted AuNPs following intravenous (i.v.) or intratumoral (i.t.) injection. For i.v. injection, the effects of GdCl3 (for deactivation of macrophages) and non-specific (anti-CD20) antibody rituximab (for blocking of Fc mediated liver and spleen uptake) were studied. It was found that HER-2 targeting via attachment of trastuzumab paradoxically decreased tumor uptake as a result of faster elimination of the targeted AuNPs from the blood while improving internalization in HER-2-positive tumor cells as compared to non-targeted AuNPs. This phenomenon could be attributed to Fc-mediated recognition and subsequent sequestration of trastuzumab conjugated AuNP by the reticuloendothelial system (RES). Blocking of the RES did not increase tumor uptake of either HER-2 targeted or non-targeted AuNPs. Following i.t. injection, our results suggest that Au-NTs redistribute over time and traffick to the liver via the ipsilateral axillary lymph node leading to comparable exposure as seen with i.v. administration. In contrast, targeted AuNPs are bound and internalized by HER-2-overexpressing tumor cells following i.t. injection, with a lower proportion of AuNPs redistributing to normal tissues. In vivo, the combination of HER-2 targeted AuNPs injected i.t. and X-radiation (11 Gy) yielded a 46% decrease in tumor size over a 4 month period in contrast to an 11.5% increase in tumor size for X-radiation treatment alone. Toxicology studies (evaluated through complete blood cell counts, by serum transaminase and creatinine measurements and by monitoring the body weight) demonstrated no apparent normal organ toxicity from the combination of HER-2 targeted AuNPs and X-radiation. These results are promising for the clinical translation of HER-2-targeted AuNPs for radiosensitization of tumors to X-radiation.

Keywords: Gold Nanoparticles
Radiation Therapy
Imaging
Antibodies
HER2
Trastuzumab
Radiosensitizer
Breast Cancer
Radionuclide
Nanomedicine
Nanoparticles
Molecular Targeting
Advisor: Raymond, Reilly
Examination of Age Differences in Incentive Motivation and Impulsivity as Possible Contributing Factors to a Susceptibility to the Effects of Drugs of Abuse during Adolescence

Rationale. Adolescence may be a period of susceptibility to the effects of drugs of abuse. This vulnerability may result from a convergence of psychological processes that contribute to drug addiction including impulsive action and incentive motivation during adolescence. Objectives. I examined age differences in incentive motivation, as measured by responding for a conditioned reinforcer (CR) previously paired with natural or drug rewards, and age and sex differences in impulsive action, as measured by responding on a differential reinforcement of low rates of responding (DRL) schedule or premature responding on the 2-Choice Serial Reaction Time Test (2-CSRTT), in Sprague-Dawley rats. The effects of drugs that affect these behaviours in adulthood and that act on neurochemical systems still developing during adolescence were also examined. Methods. In a first set of experiments (Chapter 3), I compared male adolescents and adults on responding for a CR previously paired with sucrose and the effect of amphetamine on this behaviour. In a second set of experiments (Chapter 4), I examined age differences in responding for a CR previously paired with passive or self-administered intravenous (IV) nicotine infusions. Subsequently, I investigated age and sex differences in responding on a DRL schedule in response to amphetamine (Chapter 5) and 2-CSRTT performance in response to amphetamine, nicotine and Ro 63-1908 (a glutamate N-Methyl-D-aspartic acid [NMDA] receptor subunit antagonist; Chapter 6). Results. Compared to adults, adolescents responded more for a CR previously paired with sucrose or passive, but not self-administered, IV nicotine infusions. Amphetamine only enhanced responding for a CR previously paired with sucrose. Adolescents responded more than adults on a DRL schedule, while adolescents made the most premature responses in the 2-CSRTT. No consistent sex differences were observed during the acquisition of either behaviour. Amphetamine increased premature responding most in adolescent males and adult females in the 2-CSRTT but not in responding on the DRL schedule. No consistent age or sex differences were observed for Ro 63-1908 or nicotine. Conclusions. Adolescents show enhanced impulsivity and incentive motivation than adults depending on the behavioural measure. Dopamine may contribute to age and sex differences in these behaviours.

Keywords: adolescence
addiction
impulsivity
reward
nicotine
rat
sex differences
conditioned reinforcement
self-administration
dopamine
glutamate
amphetamine
opioid
NMDA
incentive motivation
DRL
5-choice
sucrose
age differences
Advisor: Fletcher, Paul J.
Role of the Catecholamine and Limbic Systems in Narcolepsy/Cataplexy

In this thesis I investigated the neural circuits that trigger cataplexy in mice. Specifically, I first addressed the theory that cataplexy is a REM sleep disorder. I then investigated a role for the noradrenergic and dopaminergic systems in murine cataplexy. Finally, I addressed the role of the amygdala in triggering cataplexy. From this work several specific conclusions can be drawn: 1. Cataplexy does not share a common executive mechanism with REM sleep, although the two may share a common mechanism that generates muscle atonia. Muscle tone during REM sleep and cataplexy is similar, however increasing REM sleep pressure does not increase cataplexy and positive affective stimuli that can increase cataplexy tend to decrease REM sleep. 2. Systemic manipulation of dopamine receptors can modulate cataplexy without affecting behavioral state. Specifically, manipulation of D2-like dopamine receptors at specific doses can modulate cataplexy while having no affect on sleep-wake state or sleep attacks, and manipulation of D1-like receptors potently affects sleep-wake state and sleep attacks without affecting cataplexy. 3. Systemic modulation of noradrenergic activity in orexin KO mice is sufficient to modulate cataplexy. Specifically, activation of excitatory α1 receptors reduces the occurrence of cataplexy while blockade of these receptors exacerbates it. 4. Withdrawal of an endogenous α1-mediated noradrenergic drive from motor neurons during wakefulness contributed to the loss of muscle tone during cataplexy. Re-establishing this excitatory drive exogenously alleviated cataplexy-dependant muscle atonia. 5. The amygdala is a critical part of the neural mechanism that triggers cataplexy in orexin KO mice. Ablation of the amygdala resulted in significant decreases in both baseline cataplexy and emotionally-induced cataplexy. The amygdala may trigger cataplexy through direct projections to brainstem areas that regulate muscle atonia.

Keywords: Narcolepsy
Cataplexy
Sleep
Amygdala
Dopamine
Noradrenalin
Advisor: Peever, John H.
Verdazyl Radicals as Substrates for Organic Synthesis

Verdazyl radicals, discovered in 1963, are a family of exceptionally stable radicals defined by their 6-membered ring containing four nitrogen atoms. Verdazyl radicals are highly modular compounds with a large assortment of substitution patterns reported. Their stability and high degree of structural variability has been exploited in the fields of materials, inorganic, polymer and physical chemistry; however their deliberate use as starting materials towards organic synthesis had only been reported in recent years by the Georges lab. In 2008, the Georges group reported a disproportionation reaction that was observed to a occur with 6-oxoverdazyl radicals resulting in azomethine imines capable of undergoing 1,3-dipolar cycloaddition reactions. With this discovery, the door to using verdazyl radicals as substrates towards organic synthesis had been opened. Their utility in synthesis was soon discovered not to be limited to just the cycloadducts their azomethine imine derivatives could generate but also the increasing number of N-heterocycles that could be generated from these cycloadducts via unique rearrangement reactions, a major theme of this thesis. In addition, triphenyl verdazyl radicals, a distinct class of verdazyl radicals, has been shown to react with alkynes by direct radical addition and rearrangement to afford isoquinolines. As part of this thesis, a new synthetic methodology of generating 6-oxoverdazyl radicals is reported that does not rely on the use of phosgene or hydrazines. This new synthesis allows for the expansion of available alkyl substituents possible on N1 and N5 positions of 6-oxoverdazyl radicals, as well as, generation of unsymmetrical examples of 6-oxoverdazyl radicals with non-identical N1 and N5 alkyl substituents. Employing the new 6-oxoverdazyl radicals synthesized via this method, a study on the effects of different alkyl substituents on the disproportionation reaction of 6-oxoverdazyls was undertaken. Lastly, given the assortment of N-heterocyclic molecular scaffolds capable of being synthesised starting from verdazyl radicals as precursors, the applicability of verdazyl radicals in making a diversity oriented synthesis (DOS) based library was explored. In a group effort with other Georges lab members, a small library composed of various classes of verdazyl radical derived compounds was synthesized and non-specifically tested for cytotoxicity against acute myeloid leukemia and multiple myeloma cell lines in collaboration with The Princess Margaret Hospital. One example was shown to effectively kill cancer cells in both these lines in 250 μM concentration pointing out the potential of using verdazyl radical based chemistry in drug discovery.

Keywords: verdazyl
radical
cycloaddition
heterocycle
rearrangement
Advisor: Georges, Michael
A Role for Adult Born Neurons in Memory Processing

Throughout adulthood, the brain continuously generates new neurons in two neurogenic regions: the subgranular zone of the hippocampus and the subventricular zone on the lateral wall of the lateral ventricles. These neurons have been shown to integrate into hippocampal and olfactory bulb circuitry, respectively. Nevertheless, their specific contribution to hippocampal or olfactory function remains unclear. Previous studies have tried to assess adult born neuron contribution to memory function by suppressing neurogenesis and examining the impact on memory acquisition. Although ablation of neurogenesis has been shown to impair performance in hippocampus dependent and olfactory tasks, many studies fail to see an effect. Compensation from residual cells in either system after ablation may underlie these contradictory findings. Thus, a more direct approach to answer this question would be to ablate adult born neurons after their incorporation into the memory trace. To do this, we established a double transgenic strategy to tag and selectively ablate adult born neurons with temporal control. Ablation of a population of predominantly mature, adult generated dentate granule cells did not prevent acquisition of contextual fear conditioning or Morris Water Maze memories. Removal of that same population of cells after training, however, led to memory degradation in three hippocampus dependent tasks. Similarly, post-training ablation of a population of adult generated olfactory interneurons iii impaired performance in an associative odour memory task, whereas pre-training ablation had no impact. Together, these data show that adult generated neurons form a crucial component of both hippocampal and olfactory memory traces.

Keywords: adult neurogenesis
memory
Advisor: Frankland, Paul
Primus Theatre: Establishing an Alternative Model for Creating Theatre in English Canada

This study of Primus Theatre is evidence of many things. First and foremost it is a long overdue print recognition of Primus Theatre's substantial artistic accomplishments and its important contribution to the development of theatre-making in English-speaking Canada. In examining the various factors contributing to the founding of the theatre company and the extremely challenging conditions in which company members functioned over the years, it remains truly remarkable that Primus Theatre existed at all. Three central determinations emerge from the examination of Primus Theatre's practice. The theatre company truly was a pioneering venture in English Canada. Company members established an "as-if-permanent" ensemble that engaged in the creation of original performance work drawn from research that emerged from their regular training practice. The company adopted a theatre-making practice generated by the Odin Theatre in Denmark and then adapted it to vastly different cultural and fiscal contexts. It can also be determined that the origins of the company are inextricably bound to Artistic Director Richard Fowler's personal artistic journey. His strong sense of the creative and communal potential for theatre not only fuelled his own creative journey but also inspired National Theatre School students to launch their own acts of courage. The third determination arising from this study is that, while all aspects of Primus Theatre's creative practice can be linked to that of the Odin Theatre, this relationship can most accurately be described as an imprinting, rather than as an extension, of Odin Theatre practices. The conscious and unconscious permutation and advancement of the practice, driven by the technical and creative needs and interests of the young Canadian company and deeply affected by substantial financial hardships and creative set-backs, forced Primus to emerge as a unique theatrical entity developing from a particular and identifiable geneology. This study of the establishment of Primus Theatre also provides evidence that the substantial hardships faced by company members did not dissuade them from advancing their practice of continued exploration of form and expression. The study provides evidence not only of Primus Theatre's substantial body of creative work but also of its substantial pedagogical efforts. Subsequently, a new generation of theatre artists has been inspired by and trained in this alternative theatre-making model, and are making their own contributions to the continued redefinition of theatre in English Canada.

Keywords: devised theatre
performance
Advisor: Barton, Bruce
In-between Words: Late Modernist Style in the Novels of Henry Green, Ivy Compton-Burnett, Samuel Beckett, and Elizabeth Bowen

This dissertation seeks to identify, contextualize, and explain the achievement of late modernist novelists. Late modernism represents a significant, under-examined chapter in the development of the twentieth-century novel. Unlike the majority of their peers in the decades after modernism’s height, novelists such as Henry Green, Ivy Compton-Burnett, and Elizabeth Bowen—and the best-known, Samuel Beckett—continue to innovate in prose rather than returning to realism. Unlike their predecessors, late modernists move towards doubt, eschewing the sometimes ultimately redemptive ethos of high modernism. They do so without the insistence of later postmodernists, however, or their playful mood. The result is something new, strange, and “in between.” The aims of this study are to specify the nature of late modernist style, place it in its aesthetic and historical context, and explain its significance. Each chapter is a close reading of key works by one writer: each novelist uses different techniques to add to the late modernist aesthetic, but they all move in the same direction. The first chapter explores Henry Green’s work, analyzing the textual omissions and narrative construction that make his novels so evasive. In Compton-Burnett’s case, the focus is on how dialogue creates a constantly shifting moral world in which nothing can be taken for granted. The chapter on Beckett explores repetition, both as a microscopic stylistic tool and an organizing device that prevents the text from reaching conclusion. In examining Bowen, the centre is how her syntax circles continually around various kinds of “nothingness” and self-reflexively suggests ways to explore it. This study arranges late modernist novelists in a new continuum alongside Samuel Beckett, with the result that Beckett seems less a unique genius, and the other late modernist writers seem less eccentric and more profoundly challenging. They all seek ways to go on writing when doing so seems impossible. Late modernists bring something new to the novel. Through the smallest stylistic gestures, their works make and unmake themselves, refusing to allow the reader finality. They avoid the aesthetic and philosophical associations of either consolation or utter uncertainty; late modernists matter by refusing to matter in a familiar way.

Keywords: Modernism
Late Modernism
Style
Repetition
Novel
Syntax
Omission
Doubt
Beckett, Samuel
Green, Henry
Compton-Burnett, Ivy
Bowen, Elizabeth
Dialogue
Advisor: Henderson, Greig
Geography and Space in the Poetry of Prudentius

This dissertation examines the themes of geography and space in the poetry of the late antique Latin poet Prudentius (348-c.405 CE). The first chapter discusses the geography of reading, and suggests that Prudentius’ Peristephanon provides a means for the reader to experience the sites of the cults of the martyrs by reading about them rather than by having to travel to see them. It is also argued that the varying orders of the poems of the Peristephanon in the manuscript tradition can be explained by the differing interests of early readers, and that the arrangement extant in one group of manuscripts can be seen to be the result of organising the poems to fit a geographical itinerary. The second chapter investigates the intertextual aspect of literary journeys, and argues that late antique descriptions of journeys are as much indebted to the literary tradition as they are to “lived” experience on the part of the narrator. This chapter focuses in particular on Ausonius' Mosella, and the third, ninth, and eleventh hymns of Prudentius' Peristephanon. The third chapter discusses the representation of the city in the works of Prudentius, and shows how Prudentius’ approach to the civic nature of martyrdom in the Peristephanon must be related to the contemporary Christian perception that earthly civic obligations are not fundamentally incompatible with participation in the heavenly city of the afterlife. The fourth chapter examines the representation of pastoral spaces in the Liber Cathemerinon and the discussion of farming and religion in the Contra Orationem Symmachi. The final chapter addresses Prudentius' descriptions of works of art and architecture, particularly churches, and argues that Prudentius exhibits a marked preference for the word over the image as a means of conveying knowledge. A brief conclusion suggests that Prudentius’ representation of physical and imaginary spaces is always governed by a belief in the primacy of the written word, and by a fundamentally bookish approach to the world.

Keywords: Latin poetry
Prudentius
Advisor: Dewar, Michael