• The expression and development of teachers' capacities within two learning communities : a participant-observer case study

      Pancucci, Sonya; Department of Graduate and Undergraduate Studies in Education (Brock University, 2010-10-27)
      The learning community model has been an integral component of teacher development in Ontarian schools and beyond. This research was conducted to understand how teachers' personal capacity and professional, interpersonal, and organizational competencies are developed and expressed within this context. Nineteen elementary teachers and administrators participated in the study from November through January 2007. A qualitative case study methodology was used to investigate the role ofteachers' capacities and competencies in learning communities. Combined data sources from semistructured interviews, research journals, and document review were used to gather data about teachers' capacities and competencies. The study included 3 phases of analysis. In the final phase the analysis provided 3 qualities of the teachers at Jude and Mountain Schools (pseudonyms): identification as professionals, investment in others, and institutional affiliation that may explain how they differed from other educators. The data revealed these three themes, which provided an understanding of educators at Jude and Mountain Schools as dedicated professionals pushing practices to contribute to school life and address student learning needs, and as teachers who reflected on practices to continue expanding their skills. Teachers were heavily invested in creating a caring culture and in students' and team members' learning. Educators actively participated in solving problems and coplanning throughout the school levels and beyond, assumed collective responsibility for all pupils, and focused on generating school-wide consistent practices. These qualities and action patterns revealed teachers who invested time and effort in their colleagues, who committed to develop as professionals, and who affiliated closely with every aspect of school living.
    • Extending Intergroup Contact Theory to Men’s Anti-Women Biases

      Earle, Megan; Department of Psychology
      Men’s exploitation of women in heterosexual relationships is commonplace, both through sexually assaulting or otherwise taking advantage of women’s bodies, and in exploiting women for domestic labour such as housework and childcare. In the current investigation, we first present evidence for the co-occurrence of men’s willingness to sexually exploit and their willingness to domestically exploit their partners, then assess predictors and emotional processes underlying such hostility. Specifically, in Chapter 2, we develop a two-dimensional scale of willingness to exploit women with male participants (Study 1a; n = 103) and provide evidence that sexual exploitation willingness and domestic exploitation willingness are indeed separate, but related, factors. In Study 1b, we perform confirmatory analysis of this measure in two additional samples (n = 129 and n = 632 respectively) and provide evidence of construct validity for the scale. Then, Study 1c (n = 281) we provide evidence for stability of the construct over time, as well as its ability to predict behavioural indicators of exploitation. In Chapter 3, we investigate predictors and emotional processes underlying anti-women hostility and willingness to exploit women drawing on intergroup contact theory. In a correlational investigation (Study 2; n = 229), we find that perceived negative experiences with women predict greater anti-women bias via greater anger toward women. We then confirm this pattern of results using an experimental manipulation in Study 3 (n = 174), finding indirect effects of anger toward women in the relation between negative contact condition (vs. control) and greater anti-women bias. Positive contact, in contrast, has little relation with more positive attitudes toward women. Finally, in a three-wave longitudinal investigation (n = 577), Study 4 presents evidence for more nuanced relations between perceived contact, anger, and anti-women hostility; the findings suggest that not only do negative contact experiences predict downstream anger toward women, but also that anger and anti-women attitudes feed into men’s perceptions of their contact experiences with women. Overall, these findings reveal that perceived negative (but not positive) contact with, and anger toward, women are particularly relevant to understanding anti-women biases in heterosexual relations and future directions for reducing anti-women hostility are discussed.
    • Fabrication and Characterization of CoFe2O4-BiFeO3 Core Shell Nanocomposite and SrFe(12−2x)CoxRuxO19 Hexaferrites

      Monfared, Sara; Department of Physics
      This thesis consists of three parts. The first section is about CoFe2O4-BiFeO3 core-shell multiferroic nanocomposite synthesized via a two-step wet-chemical process. The presence of both spinel and perovskite constituents as well as the core-shell structure of nanocomposite have been identified using x-ray diffraction and high-resolution transmission electron microscopy, respectively. Low temperature (5 K) magnetic measurement exhibited a significant exchange bias in the core-shell nanocomposite which confirms promising connectivity of the constituents in the interface. An enhancement in magneto-dielectric of the core-shell nanocomposite over the CoFe2O4-BiFeO3 (0-3)-type nanocomposites has been seen. Further study on the magneto-loss demonstrated the contribution of the magneto-electric and Maxwell-Wagner effects in magneto-dielectric of the core-shell nanocomposite. The second part of this thesis has focused on the bulk of SrFe(12−2x)CoxRuxO19 (x = 0, 0.1, 0.2, 0.3, 0.4) which have been synthesized through the solid-state reaction process. DC magnetic measurement at room temperature exhibited a significant reduction in the coercive field of samples as the concentration of dopants increased. Contrary, an increase in the saturation magnetization was observed in the doped samples. Furthermore, a transition from conical to uniaxial anisotropy has been seen for the doped samples above x=0.3. Thin films of SrFe(12−2x)CoxRuxO19 / (111) SrTiO3 fabricated by a pulsed laser deposition technique, have been studied in the last part of this work. High-resolution parallel beam x-ray diffraction results have shown single orientations for all thin films except one. The thickness of thin films has been determined by the x-ray reflectivity measurement. A certain level of mosaicity has been detected in the prepared films using the rocking curve measurement. The strain and the epitaxial growth of thin films have been investigated utilizing the reciprocal space map technique. Finally, in-plane pole figure measurements revealed high textured films with three-fold and six-fold hexagonal symmetry. The formation of a perpendicular anisotropy in Co-Ru doped Sr-M thin films has been detected from room temperature magnetic measurement. The distribution of Co2+ and Ru4+ ions in different interstitial spaces, the thickness of films, and change in the magneto-anisotropy with a concentration of dopants have a significant effect on the magnetic characteristic of thin films.
    • Facebooking for Feminism: Social Network Sites as Feminist Learning Spaces

      Lane, Laura; Social Justice and Equity Studies Program
      Social media such as Facebook have become a significant space where social interactions increasingly take place. Within these spaces, users construct and engage with information that may facilitate social movements such as feminism. This study explored ways feminists learn, challenge, and reproduce discourses related to gender and feminism through Facebook. This research is positioned within current literature and theory related to gendered contexts of social media engagement and feminist social movement learning. Using qualitative interviews and a digital focus group, I investigated the experiences of 9 women who either learn about or engage with feminism through Facebook. Using critical feminist discourse analysis, I coded and analyzed themes that related to ways feminism is represented, constructed, navigated, and limited through Facebook. Specifically, I considered ways in which feminism can be learned, ways Facebook can be used as a learning platform, and ways gendered power relations can influence feminist engagement online. I advocate for continued exploration of and engagement with feminist uses of Facebook.
    • THE FACIAL WIDTH-TO-HEIGHT RATIO AND ITS ROLE IN ADVERTISEMENTS AND ASSESSMENTS OF THREAT POTENTIAL

      Geniole, Shawn; Department of Psychology
      As do many species, humans visually assess the ability and propensity of others to cause trouble or harm (threat potential), although the mechanisms that guide this ability are unknown. One potential mechanism that may underlie advertisements and assessments of threat is the facial width-to-height ratio (face ratio). The overarching goal of this thesis was to test both the ecological validity of the face ratio (i.e., the extent to which it maps onto an individual’s actual threat potential), and its utility in influencing observers’ first impressions of traits related to threat potential. In Chapter 2, I found that men (n = 146) but not women (n = 76) with larger face ratios were more likely to cheat in a lottery for a cash prize than were men with smaller face ratios. In Chapter 3, to better identify the precise social function of the metric, I examined its differential association with two types of threat-related judgements, untrustworthiness and aggressiveness. The face ratio (n of faces = 141) was more strongly linked to observers’ (n = 129) judgements of aggression than to their judgements of trust, although it is possible that this metric advertises threat potential more generally, of which aggression is a best indicator. In Chapter 4 (which extended some preliminary, additional findings from Chapter 3), I found that observers’ (n = 56) judgements of aggression were strongly correlated with the face ratio (n of faces = 25) even when men were bearded, suggesting that this metric could have been operational in our ancestral past when interactions likely involved bearded men. In Chapter 5, I combined effect sizes from experiments conducted from several independent labs and identified significant (albeit weak) associations between the face ratio and actual threat behaviour, and significant (and stronger) associations between the face ratio and judgements of threat potential. Together, this body of work provides initial evidence that the face ratio, and sensitivity to it, may be part of an evolved system designed for advertising and assessing threat in humans, akin to threat assessment systems identified in other species.
    • Facilitating an Educational Development Initiative Focused on Reading Comprehension Instruction: Exploring University Professors' Experiences and Beliefs

      Parr, Cynthia; Department of Graduate and Undergraduate Studies in Education
      This qualitative exploratory case study focused on the experiences of university professors as they implemented reading comprehension instruction in their discipline-specific first- and second-year courses within the context of an educational development initiative. During 3 individual interviews, a pre-instructional dialogue, and 2 group sessions across 1 academic year, 5 professors reflected on their beliefs about reading and teaching as they engaged with planning and implementation of reading comprehension instruction. Collectively, participants appeared to plan comprehension instruction in ways consistent with their beliefs about academic reading, teaching first- and second-year students, and prior instructional approaches, and cited learning that challenged, confirmed, and/or intensified their pre-existing beliefs. Participants also suggested that a variety of formats for interaction and information dissemination during the educational development initiative were valuable in that they allowed for flexible facilitation. The study may offer insights into reading comprehension and its instruction within university courses as well as personalized educational development for university professors. Participants’ beliefs, experiences, and meaning making processes are positioned as influences on learning, and participants’ investments of self during educational development are emphasized. Implications for theory include the importance of acknowledging and honouring the complexities of professors’ investments of self in the design and facilitation of initiatives. Related implications for practice include exploration of professors’ beliefs, demonstrated respect and consideration, and responsive communication. Recommendations for future research include extension of the study’s scope and lines of inquiry.
    • The Fast Regulation of Photosynthesis in Diatoms: an inquiry into the physiological and physical origins of non-photochemical chlorophyll fluorescence quenching.

      Derks, Allen Kimbell; Department of Biological Sciences (Brock University, 2015-01-06)
      Diatoms are renowned for their robust ability to perform NPQ (Non-Photochemical Quenching of chlorophyll fluorescence) as a dissipative response to heightened light stress on photosystem II, plausibly explaining their dominance over other algal groups in turbulent light environs. Their NPQ mechanism has been principally attributed to a xanthophyll cycle involving the lumenal pH regulated reversible de-epoxidation of diadinoxanthin. The principal goal of this dissertation is to reveal the physiological and physical origins and consequences of the NPQ response in diatoms during short-term transitions to excessive irradiation. The investigation involves diatom species from different originating light environs to highlight the diversity of diatom NPQ and to facilitate the detection of core mechanisms common among the diatoms as a group. A chiefly spectroscopic approach was used to investigate NPQ in diatom cells. Prime methodologies include: the real time monitoring of PSII excitation and de-excitation pathways via PAM fluorometry and pigment interconversion via transient absorbance measurements, the collection of cryogenic absorbance spectra to measure pigment energy levels, and the collection of cryogenic fluorescence spectra and room temperature picosecond time resolved fluorescence decay spectra to study excitation energy transfer and dissipation. Chemical inhibitors that target the trans-thylakoid pH gradient, the enzyme responsible for diadinoxanthin de-epoxidation, and photosynthetic electron flow were additionally used to experimentally manipulate the NPQ response. Multifaceted analyses of the NPQ responses from two previously un-photosynthetically characterised species, Nitzschia curvilineata and Navicula sp., were used to identify an excitation pressure relief ‘strategy’ for each species. Three key areas of NPQ were examined: (i) the NPQ activation/deactivation processes, (ii) how NPQ affects the collection, dissipation, and usage of absorbed light energy, and (iii) the interdependence of NPQ and photosynthetic electron flow. It was found that Nitzschia cells regulate excitation pressure via performing a high amplitude, reversible antenna based quenching which is dependent on the de-epoxidation of diadinoxanthin. In Navicula cells excitation pressure could be effectively regulated solely within the PSII reaction centre, whilst antenna based, diadinoxanthin de-epoxidation dependent quenching was implicated to be used as a supplemental, long-lasting source of excitation energy dissipation. These strategies for excitation balance were discussed in the context of resource partitioning under these species’ originating light climates. A more detailed investigation of the NPQ response in Nitzschia was used to develop a comprehensive model describing the mechanism for antenna centred non-photochemical quenching in this species. The experimental evidence was strongly supportive of a mechanism whereby: an acidic lumen triggers the diadinoxanthin de-epoxidation and protonation mediated aggregation of light harvesting complexes leading to the formation of quencher chlorophyll a-chlorophyll a dimers with short-lived excited states; quenching relaxes when a rise in lumen pH triggers the dispersal of light harvesting complex aggregates via deprotonation events and the input of diadinoxanthin. This model may also be applicable for describing antenna based NPQ in other diatom species.
    • Force potentiation as a modulator of contractile performance: Implications for control of skeletal muscle force and energetics of work

      Gittings, William J.; Applied Health Sciences Program
      This thesis investigated the modulation of dynamic contractile function and energetics of work by posttetanic potentiation (PTP). Mechanical experiments were conducted in vitro using software-controlled protocols to stimulate/determine contractile function during ramp shortening, and muscles were frozen during parallel incubations for biochemical analysis. The central feature of this research was the comparison of fast hindlimb muscles from wildtype and skeletal myosin light chain kinase knockout (skMLCK-/-) mice that does not express the primary mechanism for PTP: myosin regulatory light chain (RLC) phosphorylation. In contrast to smooth/cardiac muscles where RLC phosphorylation is indispensable, its precise physiological role in skeletal muscle is unclear. It was initially determined that tetanic potentiation was shortening speed dependent, and this sensitivity of the PTP mechanism to muscle shortening extended the stimulation frequency domain over which PTP was manifest. Thus, the physiological utility of RLC phosphorylation to augment contractile function in vivo may be more extensive than previously considered. Subsequent experiments studied the contraction-type dependence for PTP and demonstrated that the enhancement of contractile function was dependent on force level. Surprisingly, in the absence of RLC phosphorylation, skMLCK-/- muscles exhibited significant concentric PTP; consequently, up to ~50% of the dynamic PTP response in wildtype muscle may be attributed to an alternate mechanism. When the interaction of PTP and the catchlike property (CLP) was examined, we determined that unlike the acute augmentation of peak force by the CLP, RLC phosphorylation produced a longer-lasting enhancement of force and work in the potentiated state. Nevertheless, despite the apparent interference between these mechanisms, both offer physiological utility and may be complementary in achieving optimal contractile function in vivo. Finally, when the energetic implications of PTP were explored, we determined that during a brief period of repetitive concentric activation, total work performed was ~60% greater in wildtype vs. skMLCK-/- muscles but there was no genotype difference in High-Energy Phosphate Consumption or Economy (i.e. HEPC: work). In summary, this thesis provides novel insight into the modulatory effects of PTP and RLC phosphorylation, and through the observation of alternative mechanisms for PTP we further develop our understanding of the history-dependence of fast skeletal muscle function.
    • From the ground up : understanding how teachers and administrators make sense of tension

      Fenton, Nancy E.; Department of Graduate and Undergraduate Studies in Education (Brock University, 2006-05-28)
      Strategies designed to improve educational systems have created tensions in school personnel as they struggle to respond to competing demands of ongoing change within their daily realities. The purpose of this case study was to investigate how teachers and administrators in one elementary school made sense ofthese tensions and to explore the factors that constrained or shaped their responses. A constructive interpretative case study using a grounded theory approach was used. Qualitative data were collected through document analysis, semi-structured interviews, and participant observation. In-depth information about teachers' and administrators' experiences and a contextual understanding oftension was generated from inductive analysis of the data. The study found that tension was a phenomenon situated in the context in which it arose. A contextual understanding of tension revealed the interactions between the institutional, personal, and emotional domains that continually shaped individual and group behavioural responses. This contextual understanding of tension provided the means to reinterpret resistance to change. It also helped to show how teachers and administrators reconstructed identities and made sense in context.. Of particular note was the crucial nature of the conditions under which teachers and adlninistrators shaped meaning and understood change. This study sheds light on the contextual intricacies of tension that may help leaders with the complex design and implementation of educational change..
    • Functional antagonism of the mesolimbic dopaminergic system on mesolimbic cholinergic system in the vocal expression of an emotional state

      Silkstone, Michael; Department of Biological Sciences
      The overarching goal of this thesis was to determine if the initiation of a positive emotional state could antagonize the expression of a negative emotional state in rats. The hypothesis of the thesis argued that the initiation of a positive emotional state would ameliorate the vocal expression of a negative emotional state. The subjective emotional state of the rat was indexed by the quantity and type of pharmacologically induced ultrasonic vocalizations (USVs). Adolescent and adult rats can emit vocalizations above the upper threshold of human hearing (>20 kHz) termed ultrasonic vocalizations (USVs). These USVs are broadly divided into 50-kHz, reflective of a positive emotional state, and 22-kHz USVs, reflective of a negative emotional state. Pharmacologically, injection of dopamine agonists into the nucleus accumbens shell is sufficient for the initiation of 50-kHz USVs, while injection of cholinergic agonists into the anterior hypothalamic-medial preoptic area (AH-MPO) or the lateral septum (LS) can initiate 22-kHz USVs. In chapter two of the thesis, I demonstrated that microinjection of the dopamine agonist, apomorphine, into the medial shell of the nucleus accumbens attenuated the extent of carbachol-induced 22-kHz USVs from the AH-MPO. I also demonstrated that this effect was dependent upon the microinjection of apomorphine into the central region of the nucleus accumbens shell. In chapter three, I demonstrated that apomorphine could also decrease the extent of carbachol-induced 22-kHz USVs from the LS providing evidence that the effect reported in chapter two was not isolated to the AH-MPO, but rather extending along the medial cholinoceptive vocalization strip. In the third chapter. I also demonstrated that the magnitude of the reduction in the number of 22-kHz USVs was correlated to the number of emitted frequency-modulated (FM) 50-kHz USVs induced by apomorphine. In the fourth chapter, I investigated whether blocking dopamine receptors, either systemically using the typical D2-antipsychotic agent, haloperidol, or microinjection of the D2 antagonist, raclopride, into the nucleus accumbens shell could increase the emission of carbachol-induced 22-kHz USVs from the LS. The results showed that antagonism of dopamine receptors, either systemically or intracerebrally, did not increase the number of 22-kHz USVs. Interestingly, it was also observed that after the prolonged recording of carbachol-induced 22-kHz USVs, some 50-kHz USVs spontaneously appeared after roughly 300 s into the recording. I argued that these 50-kHz USVs, which I defined as “rebound 50-kHz USVs” are not initiated by carbachol since they occurred when the carbachol-response weaned. It was also demonstrated these rebound 50-kHz USVs were dependent upon dopamine release within the nucleus accumbens since both systemic, and intracerebral application of dopamine antagonists into the central division of the nucleus accumbens shell blocked the occurrence of rebound 50-kHz USVs. Altogether, the data supports the thesis that activation of a positive emotional state decreases the expression of the negative emotional state in rats when measured using ultrasonic vocalizations.
    • Functional Characterization of Monoterpenoid Indole Alkaloid (MIA) Biosynthetic Genes in Catharanthus roseus

      Salim, Vonny; Centre for Biotechnology (Brock University, 2013-08-23)
      The monoterpenoid indole alkaloids (MIAs) of Madagascar periwinkle (Catharanthus roseus) are known to be among the most important source of natural drugs used in various cancer chemotherapies. MIAs are derived by combining the iridoid secologanin with tryptamine to form the central precursor strictosidine that is then converted to most known MIAs, such as catharanthine and vindoline that dimerize to form anticancer vinblastine and vincristine. While their assembly is still poorly understood, the complex multistep pathways involved occur in several specialized cell types within leaves that are regulated by developmental and environmental cues. The organization of MIA pathways is also coupled to secretory mechanisms that allow the accumulation of catharanthine in the waxy leaf surface, separated from vindoline found within leaf cells. While the spatial separation of catharanthine and vindoline provides an explanation for the low levels of dimeric MIAs found in the plants, the secretion of catharanthine to the leaf surface is shown to be part of plant defense mechanisms against fungal infection and insect herbivores. The transcriptomic databases of Catharanthus roseus and various MIA producing plants are facilitating bioinformatic approaches to identify novel MIA biosynthetic genes. Virus-induced gene silencing (VIGS) is being used to screen these candidate genes for their involvement in iridoid biosynthesis pathway, especially in the identification of 7-deoxyloganic acid 7-hydroxylase (CrDL7H) shown by the accumulation of its substrate, 7-deoxyloganic acid and decreased level of secologanin along with catharanthine and vindoline. VIGS can also confirm the biochemical function of genes being identified, such as in the glucosylation of 7-deoxyloganetic acid by CrUGT8 shown by decreased level of secologanin and MIAs within silenced plants. Silencing of other iridoid biosynthetic genes, loganic acid O-methyltransferase (LAMT) and secologanin synthase (SLS) also confirm the metabolic route for iridoid biosynthesis in planta through 7-deoxyloganic acid, loganic acid, and loganin intermediates. This route is validated by high substrate specificity of CrUGT8 for 7-deoxyloganetic acid and CrDL7H for 7-deoxyloganic acid. Further localization studies of CrUGT8 and CrDL7H also show that these genes are preferentially expressed within Catharanthus leaves rather than in epidermal cells where the last two steps of secologanin biosynthesis occur.
    • Functional genomics of monoterpenoid indole alkaloid biosynthesis in Rauvolfia serpentina

      Cazares, Paulo; Department of Biological Sciences
      Monoterpenoid indole alkaloids (MIAs) are a large and heterogeneous group of nitrogen-containing specialized metabolites produced by plants belonging to the Apocynaceae, Loganiaceae and Rubiaceae families. Many of these MIAs exhibit interesting biological activities and are currently used as pharmaceutical drugs to treat several medical conditions. Thus, the biosynthetic pathways responsible for their production have been extensively investigated. Recent advancements in large-scale DNA-sequencing technologies have provided access to a vast collection of genes. Here we have used bioinformatics guided screen to identify candidate genes involved in MIA biosynthesis in Rauvolfia serpentina. We utilized our large annotated transcriptome databases (www.phytometasyn.ca) as a source to mine genes. The identification of a Catharanthus roseus enzyme responsible for indole nitrogen methylation of an MIA intermediate of the vindoline pathway provided us with a query sequence to mine candidate genes responsible for N-methylation of other MIAs in R. serpentina. This led to the identification, molecular cloning and biochemical characterization of four enzymes catalyzing N-methylation. Two separate genes cloned from R. serpentina and V. minor, both encoded enzymes displaying high affinity and specificity for picrinine converting it to N-methyl-picrinine (ervincine) in the presence of S-adenosyl-L-methionine. The other two genes, cloned from R. serpentina, encoded enzymes involved in final steps of ajmaline biosynthesis. Norajmaline N-methyltransferase catalyzed the indoline N-methylation of norajmaline to generate ajmaline, while ajmaline Nβ-methyltransferase catalyzed the side chain N-methylation of ajmaline to generate Nβ-methylajmaline, an unusual positively charge MIA molecule found in Rauvolfia.
    • Functional genomics of O-glucosyltransferases from Concord grape (Vitis labrusca)

      Hall, Dawn.; Department of Biological Sciences (Brock University, 2007-05-28)
      Grape (Vitis spp.) is a culturally and economically important crop plant that has been cultivated for thousands of years, primarily for the production of wine. Grape berries accumulate a myriad of phenylpropanoid secondary metabolites, many of which are glucosylated in plantae More than 90 O-glucosyltransferases have been cloned and biochemically characterized from plants, only two of which have been isolated from Vitis spp. The world-wide economic importance of grapes as a crop plant, the human health benefits associated with increased consumption of grape-derived metabolites, the biological relevance of glucosylation, and the lack of information about Vitis glucosyltransferases has inspired the identification, cloning and biochemical characterization of five novel "family 1" O-glucosyltransferases from Concord grape (Vitis labrusca cv. Concord). Protein purification and associated protein sequencIng led to the molecular cloning of UDP-glucose: resveratrollhydroxycinnamic acid O-glucosyltransferase (VLRSGT) from Vitis labrusca berry mesocarp tissue. In addition to being the first glucosyltransferase which accepts trans-resveratrol as a substrate to be characterized in vitro, the recombinant VLRSGT preferentially produces the glucose esters of hydroxycinnamic acids at pH 6.0, and the glucosides of trans-resveratrol and flavonols at 'pH 9.0; the first demonstration of pH-dependent bifunctional glucosylation for this class of enzymes. Gene expression and metabolite profiling support a role for this enzyme in the bifuncitonal glucosylation ofstilbenes and hydroxycinnamic acids in plantae A homology-based approach to cloning was used to identify three enzymes from the Vitis vinifera TIGR grape gene index which had high levels of protein sequence iii identity to previously characterized UDP-glucose: anthocyanin 5-0-glucosyltransferases. Molecular cloning and biochemical characterization demonstrated that these enzymes (rVLOGTl, rVLOGT2, rVLOGT3) glucosylate the 7-0-position of flavonols and the xenobiotic 2,4,5-trichlorophenol (TCP), but not anthocyanins. Variable gene expression throughout grape berry development and enzyme assays with native grape berry protein are consistent with a role for these enzymes in the glucosylation of flavonols; while the broad substrate specificity, the ability of these enzymes to glucosylate TCP and expression of these genes in tissues which are subject to pathogen attack (berry, flower, bud) is consistent with a role for these genes in the plant defense response. Additionally, the Vitis labrusca UDP-glucose: flavonoid 3-0-glucosyltransferase (VL3GT) was identified, cloned and characterized. VL3GT has 96 % protein sequence identity to the previously characterized Vitis vinifera flavonoid 3-0-glucosyltransferase (VV3GT); and glucosylates the 3-0-position of anthocyanidins and flavonols in vitro. Despite high levels of protein sequence identity, VL3GT has distinct biochemical characteristics (as compared to VV3GT), including a preference for B-ring methylated flavonoids and the inability to use UDP-galactose as a donor substrate. RT-PCR analysis of VL3GT gene expression and enzyme assays with native grape protein is consistent with an in planta role for this enzyme in the glucosylation of anthocyanidins,but not flavonols. These studies reveal the power of combining several biochemistry- and molecular biology-based tools to identify, clone, biochemically characterize and elucidate the in planta function of several biologically relevant O-glucosyltransferases from Vitis spp.
    • Future-proofing: Exploring the value of a therapeutic recreation positive psychology intervention for supporting youth experiencing mental health challenges

      Cripps, Lauren C.; Applied Health Sciences Program
      In Canada, suicide remains the second leading cause of death for individuals aged 15 to 24, exceeded only by unintentional injuries (accidents). In 2012, suicide accounted for 15% of deaths among youth aged 10-14 years, 29% among youth aged 15-19 years and 23% among young adults aged 20-24 (Statistics Canada, 2017). Recovery supports the development of a meaningful life (as described by the individual) that includes enhanced traits and practices that are specifically intended to maintain one’s level of satisfaction in everyday life, while supporting the management of recurring symptoms and/or changes in current life circumstances (Andresen, Oades, & Caputi, 2011; Kleiber, Hutchinson, & Williams, 2002; McCormick & Iwasaki, 2008; McCormick & Iwasaki, 2008; McCormick, 1999). This recovery-oriented project was a qualitative, interpretative phenomenological study guided by the evidenced-informed process as a framework for program design, implementation and evaluation. This project sought to critically explore mental health as it pertains to adolescents through the design, implementation and evaluation of a therapeutic recreation intervention designed for youth living in a residential treatment setting. This project provides evidence that the BYBS-Y program has the potential to support change with the participants. This project also demonstrates new learning and is an illustration of the potential connection between a strengths perspective and supporting essential tasks assigned to development and recovery. By implementing a three-phase process this research shows the value of feedback from both practitioners and clients, affirming that our greatest insights are always gained from those with lived experience. Finally, this project provides evidence for the contribution of TR services in the recovery process, suggesting that by focusing on the development of skills and capacities that are likely to generate emotion, highlight strengths, support choice and create opportunities for positive social connections, it is likely that youth can increase the resiliency necessary to buffer the effects of chronic symptoms and in turn begin to envision (and obtain) a life that includes, but is not defined by illness.
    • Genetic and Electrophysiological Correlates of Self-Regulation in Adolescence

      Lackner, Christine; Department of Psychology
      Self-regulation is considered a powerful predictor of behavioral and mental health outcomes during adolescence and emerging adulthood. In this dissertation I address some electrophysiological and genetic correlates of this important skill set in a series of four studies. Across all studies event-related potentials (ERPs) were recorded as participants responded to tones presented in attended and unattended channels in an auditory selective attention task. In Study 1, examining these ERPs in relation to parental reports on the Behavior Rating Inventory of Executive Function (BRIEF) revealed that an early frontal positivity (EFP) elicited by to-be-ignored/unattended tones was larger in those with poorer self-regulation. As is traditionally found, N1 amplitudes were more negative for the to-be-attended rather than unattended tones. Additionally, N1 latencies to unattended tones correlated with parent-ratings on the BRIEF, where shorter latencies predicted better self-regulation. In Study 2 I tested a model of the associations between selfregulation scores and allelic variations in monoamine neurotransmitter genes, and their concurrent links to ERP markers of attentional control. Allelic variations in dopaminerelated genes predicted both my ERP markers and self-regulatory variables, and played a moderating role in the association between the two. In Study 3 I examined whether training in Integra Mindfulness Martial Arts, an intervention program which trains elements of self-regulation, would lead to improvement in ERP markers of attentional control and parent-report BRIEF scores in a group of adolescents with self-regulatory difficulties. I found that those in the treatment group amplified their processing of attended relative to unattended stimuli over time, and reduced their levels of problematic behaviour whereas those in the waitlist control group showed little to no change on both of these metrics. In Study 4 I examined potential associations between self-regulation and attentional control in a group of emerging adults. Both event-related spectral perturbations (ERSPs) and intertrial coherence (ITC) in the alpha and theta range predicted individual differences in self-regulation. Across the four studies I was able to conclude that real-world self-regulation is indeed associated with the neural markers of attentional control. Targeted interventions focusing on attentional control may improve self-regulation in those experiencing difficulties in this regard.
    • “Getting Everyone on the Same Page” An Integrated Transition Planning Process for Youths with an Intellectual/Developmental Disability with a Social Return on Investment Perspective

      Readhead, Anne; Department of Child and Youth Studies
      Transitioning out of high school is a significant step in a young person’s life. The Tri-Sector TAY Planning process in the Niagara Region of Ontario, Canada has developed a single integrated transition plan for youths with an intellectual and/or developmental disability (I/DD). This plan unfolds collaboratively, with education and community professionals meeting at the same planning table with the family and the youth beginning at the age of 14 years. Notably, no new government funding was provided to support this process. The case study reported herein explored both the potential benefits of the Tri-Sector Planning process and the ways in which this multi-sector planning procedure might be improved. Semi-structured interviews were conducted with fourteen participants, including youths, parents, and professionals. A qualitative thematic data analysis was conducted. Collaboration was identified as an important component of the multi-sector integrated planning process, critical to promoting successful outcomes for youths, including gainful employment and entry into post-secondary education. On the question of possible improvements to the procedure, promoting increased youth engagement and agency during the planning process emerged as an important consideration. In addition, a Social Return on Investment (SROI) quantitative and qualitative data analysis was completed on the case study data to examine the identified impacts of the process. Even with the investment into the Niagara Region Tri-Sector TAY Planning process based only on an estimate of funding from participating organizations, the net SROI ratio was 1.00:4.92, illustrating that for every $1.00 of funding contributed by participating organizations, the after-cost impact benefit was $4.92.
    • Globalization, Postcolonialism, and Science Fiction: Nomadic Transgressions

      Kurtz, Malisa; Interdisciplinary Humanities Program
      This dissertation seeks to establish science fiction as a critical framework for interrogating contemporary neocolonial structures. Specifically, I examine the ways an emerging subgenre of “postcolonial science fiction” provides valuable conceptual tools for imagining what postcolonial relations might look like in an era defined by globalization and multinational capitalism. By linking a critique of the genre’s colonial drive to the logic of advanced capitalism, postcolonial science fiction offers a critical lens through which to examine the continuation of contemporary neocolonial structures. For example, postcolonial science fiction questions several of the assumptions that underpin science fiction, including the genre’s colonial gaze, the appeal to an ideology of progress, focus on the “future” and the construction of an assumed cosmopolitan future, and an implicit faith in technological solutions or the inclination towards techno-optimism. Postcolonial science fiction links these generic qualities to the dominance of certain ideological frameworks in contemporary neoliberal culture, revealing the colonial underpinnings of both genre and the “real-world” socio-historical contexts from which genres emerge. Importantly, postcolonial science fiction is also constructivist, offering alternative epistemological frameworks for understanding our relationship to the future beyond colonial paradigms. Through the process of deconstructing and reconstructing sf’s colonial assumptions, I see postcolonial science fiction produced from diverse national contexts as expressions of a transnational desire to understand such questions as: what do we need to do so that tomorrow is not characterized by the violence against others we exhibit today? Or, more specifically, how can we create new visions of “postcolonialism” that will materialize into more ethical practice? By explicitly foregrounding these questions postcolonial science fiction transforms the genre’s world building into a strategy of postcolonial experimentation that strives to understand the complexity of problems facing diverse global communities. Postcolonial studies might also benefit from thinking through the lens of science fiction, where creative projects function as ethical experiments towards mapping out the possibilities of transnational affiliation. As this study emphasizes, I therefore see postcolonial science fiction as simultaneously a subgenre and a process, strategy, or mode of relation established between people committed to imagining less exploitative futures.
    • Half-sandwich Complexes of Ruthenium Supported by N-Heterocyclic Carbene Ligands: Synthesis and Application to Catalysis

      Mai, Van Hung; Department of Chemistry
      This thesis presents the preparation and catalytic reactivity of novel half-sandwich ruthenium complexes supported by N-Heterocyclic Carbene (NHC) ligands. The cationic half-sandwich ruthenium complexes [Cp(IPr)Ru(CH3CN)2]+ show interesting reactivities toward the transfer hydrogenation of different unsaturated substrates, such as ketones, olefins, N-heterocycles, and nitriles. Kinetic studies disclose that a neutral trishydride ruthenium complex is actually involved in the catalytic cycle, playing the role as a resting state. Further investigations on the sub-class of trishydride ruthenium complexes bearing NHC ligands (Cp'(NHC)RuH3) reveal that these complexes have an unusual and great catalytic performance toward the hydrodefluorination (HDF) of fluorinated aromatic and aliphatic compounds. The combined kinetic studies, cross-over experiments and rate law analysis suggest an unusual mechanistic pathway for the Cp*(IPr)RuH3 catalyzed HDF. This study is one of the rare examples where isopropanol is employed as a reducing agent for the metal-mediated HDF reaction. A class of silyl dihydride ruthenium complexes, derived from Cp(IPr)RuH3 are prepared. These silyl hydrido derivatives are great compounds for the study of the inter ligand hypervalent interaction (IHI), an interesting phenomenon for many non-classical silane complexes. This study also suggests that the replacement of phosphines by their isolobally analogous NHC ligands result in stronger IHI interactions in the corresponding compounds. Another type of non-classical interaction was systematically scrutinized in a ii series of new cationic and neutral silane sigma complexes of ruthenium bearing different silyl moieties. These new NHC-supported ruthenium complexes allow for direct comparation with the known phosphine analogues, which reveals interplay of steric and electronic factors on the extent of Si-H complexation to metal and the extent of additional interligand interactions between Ru-Cl and chlorosilane ligand. Finally, new trishydride ruthenium complexes bearing NHC ligands (Cp'(NHC)RuH3) catalyze the H/D exchange reaction of various N-heterocycle substrates; their catalytic performance can be considered as one of the mildest, and most efficient approaches.
    • Half-sandwich Complexes of Ruthenium; Synthesis and Application to Catalysis

      Lee, Sun Hwa; Department of Chemistry (Brock University, 2014-09-15)
      This thesis describes syntheses and catalytic reactivity of several half-sandwich complexes of ruthenium. The neutral ruthenium trihydride complex, Cp(PPri3)RuH3(1), can efficiently catalyse the H/D exchange reaction between various organic substrates and deuterium sources, such as benzene-d6. Moreover, the H/D exchange reactions of polar substrates were also observed in D2O, which is the most attractive deuterium source due to its low cost and low toxicity. Importantly, the H/D exchange under catalytic conditions was achieved not only in aromatic compounds but also in substituted liphatic compounds. Interestingly, in the case of alkanes and alkyl chains, highly selective deuterium incorporation in the terminal methyl positions was observed. It was discovered that the methylene units are engaged in exchange only if the molecule contains a donating functional group, such as O-and N-donors, C=C double bonds, arenes and CH3. The cationic half-sandwich ruthenium complex [Cp(PPri3)Ru(CH3CN)2]+(2) catalyses the chemoselective mono-addition of HSiMe2Ph to pyridine derivatives to selectively give the 1,4-regiospecific, N-silylated products. An ionic hydrosilylation mechanismis suggested based on the experiments. To support this mechanistic proposal, kinetic studies under catalytic conditions were performed. Also, the 1,4-regioselective mono-hydrosilylation of nitrogen containing compounds such as phenanthroline, quinoline and acridine can be achieved with the related Cp*complex [Cp*(phen)Ru(CH3CN)]+(3) (phen = 1,10-phenanthroline) and HSiMe2Ph under mild conditions. The cationic ruthenium complex 2 can also be used as an efficient catalyst for transfer hydrogenation of various organic substrates including carbonyls, imines, nitriles and esters. Secondary alcohols, amines, N-isopropylidene amines and ether compounds can be obtained in moderate to high yields. In addition, other ruthenium complexes, 1,3 and [Cp*(PPri3)Ru(CH3CN)2]+(4), can catalyse transfer hydrogenation of carbonyls although the reactions were sluggish compared to the ones of 2. The possible intermediate, Cp(PPri3)Ru(CH3CN)(H), was characterized by NMR at low temperature and the kinetic studies for the transfer hydrogenation of acetophenone were performed. Recently, chemoselective reduction of acid chlorides to aldehydes catalysed by the complex 2 was reported. To extend the catalytic reactivity of 2, reduction of iminoyl chlorides, which can be readily obtained from secondary amides, to the corresponding imines and aldehydes was investigated. Various substituted iminoyl chlorides were converted into the imines and aldehydes under mild conditions and several products were isolated with moderate yields.
    • Half-sandwich silane complexes of ruthenium and iron : synthesis, structure and application to catalysis

      Gutsulyak, Dmitry V.; Department of Chemistry (Brock University, 2012-04-04)
      The present thesis describes syntheses, structural studies, and catalytic reactivity of new non-classical silane complexes of ruthenium and iron. The ruthenium complexes CpRu(PPri3)CI(T]2-HSiR3) (1) (SiR3 = SiCh (a), SiClzMe (b), SiCIMe2 (c), SiH2Ph (d), SiMe2Ph (e» were prepared by reactions of the new unsaturated complex CpRu(PPri3)CI with silanes. According to NMR studies and X-ray analyses, the complexes la-c exhibit unusual simultaneous Si··· H and Si··· CI-Ru interactions. The complex CpRu(PPri3)CI was also used for the preparation of the first examples of late transition metal agostic silylamido complexes CpRu(PPri3)(N(T]2-HSiMe2)R) (2) (R= Ar or But), which were characterized by NMR spectroscopy. The iron complexes CpFe(PMePri2)H2(SiR3) (3) (SiR3 = SiCh (a), SiClzMe (b), SiCIMe2 (c), SiH2Ph (d), SiMe2Ph (e» were synthesized by the reaction of the new borohydride iron complex CpFe(PMePri2)(B~) with silanes in the presence NEt3. The complexes 3 exhibit unprecedented two simultaneous and equivalent Si··· H interactions, which was confirmed by X-ray analyses and DFT calculations. A series of cationic ruthenium complexes [CpRu(PR3)(CH3CN)(112-HSiR'3)]BAF (PR3 = PPri 3 (4), PPh3 (5); SiR'3 = SiCh (a), SiClzMe (b), SiClMe2 (c), SiH2Ph (d), SiMe2Ph (e» was obtained by substitution of one of the labile acetonitrile ligands in [CpRu(PR3)(CH3CNh]BAF with sHanes. Analogous complexes [TpRu(PR3)(CH3CN)(T]2 -HSiR' 3)]BAF (5) were obtained by the reaction of TpRu(PR3)(CH3CN)CI with LiBAF in the presence of silanes. The complexes 4-5 were characterized by NMR spectroscopy, and the observed coupling constants J(Si-H) allowed us to estimate the extent of Si-H bond activation in these compounds. The catalytic activity in hydrosilylation reactions of all of the above complexes was examined. The most promising results were achieved with the cationic ruthenium precatalyst [CpRu(PPri3)(CH3CN)2t (6). Complex 6 shows good to excellent catalytic activity in the hydrosilylation of carbonyls, dehydrogenative coupling of silanes with alcohols, amines, acids, and reduction of acid chlorides. We also discovered very selective reduction of nitriles and pyridines into the corresponding N-silyl imines and l,4-dihydropyridines, respectively, at room temperature with the possibility of catalyst recycling. These chemoselective catalytic methods have no analogues in the literature. The reactions were proposed to proceed via an ionic mechanism with intermediate formation of the silane a-complexes 4.