• Magnetically Interesting Coordination Complexes Based on Macrocyclic Ligands

      Ras Ali, Zineb; Department of Chemistry
      The synthesis and study of select 3d and/or 4f coordination complexes prepared from crown ether and Schiff-base dual compartmental macrocycles are described herein, working towards the discovery and study of new families of macrocyclic-based single molecule magnets (SMMs). Chapter 1 introduces the general theory of magnetism, molecular magnetism and SMMs and provides the reader with a brief overview of the relevant coordination chemistry of the two families of macrocycles. In Chapter 2, two 15-crown-5 complexes [Ln(NO3)3(OH2)2(MeOH)], (where Ln(III) = Tb (I) and Dy (II)) have been prepared and characterized. X-ray diffraction studies reveal the two complexes crystallize as 1-D chains. Variable temperature ac magnetic susceptibility studies reveal that (II) is an SMM with two effective energy barriers, Ueff = 26 K (18 cm−1); τ0 = 4.10 × 10−7 s and Ueff = 41 K (29 cm−1); τ0 = 1.35 × 10−8 s, whereas ab initio studies suggest that the observation of slow relaxation of magnetization in the Tb complex (I) is hindered by the presence of rapid quantum tunneling mechanisms (QTM). Solid state photoluminescence measurements reveal the two complexes have well-resolved f–f transitions, where a Gaussian fit of the fine structure of the highest-energy emission band for the Dy(III) complex allows the Stark splitting of the ground state to be determined. In Chapter 3, select Ln(III) complexes with benzo and dibenzo 15-crown-5 macrocycles were synthesized and characterized. Reaction of Dy(III) together with benzo 15-crown-5 afforded a unique [Dy(OH2)8]3+ complex (III), where the hydrated Dy(III) cation is fully encapsulated within a supramolecular cage formed by three benzo 15-crown-5 macrocycles. Interestingly, the close to perfect square antiprismatic geometry of the 4f ion enhances its axial anisotropy, which suppresses quantum tunnelling mechanisms (QTM) in the ground and first excited states, resulting in the observation of SMM behavior in zero dc field. For this system the magnetic data were further supported by solid-state photoluminescence and ab initio studies, The introduction of a second benzene ring into the organic framework of the macrocycle increases its rigidity, where on coordination to Dy(III), affords the partially encapsulated complex (IV), which displays slow relaxation of magnetisation, consistent with SMM properties. In Chapter 4, the coordination chemistry of a dual compartmental Schiff-base macrocycle H2L3 containing O3O2 and N3O2 cavities was explored together with select 3d and 4f ions. In the first part of this chapter, the coordination chemistry of H2L3 with 3d metal ions is presented, where in the presence of NaOH, the Na(I) ions reside in the O3O2 cavity and the 3d ions occupy the second N3O2 cavity. Three coordination complexes containing Cu(II), Zn(II), and Mn(II) ions were prepared and characterized. The Cu(II), and Zn(II) complexes are monomeric with molecular formulae [CuNa(L3b)ClCH3OH]‧6H2O (V) and [ZnNa(L3b)(CH3COO)(CH3OH)]‧H2O (VI) respectively, while the Mn(II) complex crystallizes as a trimer with stoichiometry [Mn3Na2(L3)2(CH3COO)4]·5.75CH3OH·0.5H2O (VII). For complexes (V) and (VI), nucleophilic addition of the NH of the N3O2 cavity to the carbon atom of the adjacent imine results in a contraction of the N3O2 cavity and the formation of a five-membered imidazoline ring to afford the modified ligand L3b.The magnetic properties of (V) and (VII) are also reported. In the second part of this chapter, coordination of the macrocycle to select 4f ions in the absence of any base afforded the mononuclear complexes [Dy(H2L3)(H2O)2(CH3OH)2]Cl3·CH3OH, (VIII), and [Ln(H2L3)(H2O)3(CH3OH)] Cl3, where Ln(III) = Tb (IX), Er (X), and Gd (XI), in which the Ln(III) ion is coordinated in the O3O2 cavity. Magneto-structural studies on these complexes reveal that the Dy complex has a slightly different structure than the other three complexes, however all four 4f ions crystallize with square antiprismatic geometries, where only the Dy(III) complex (VIII) displays SMM properties.
    • Mechanism of tocopherol transfer by human α-tocopherol transfer protein (α-hTTP)

      Zhang, Wen Xiao; Centre for Biotechnology (Brock University, 2010-10-26)
      Vitamin E is a well known fat soluble chain breaking antioxidant. It is a general tenn used to describe a family of eight stereoisomers of tocopherols. Selective retention of a-tocopherol in the human circulation system is regulated by the a -Tocopherol Transfer Protein (a-TIP). Using a fluorescently labelled a-tocopherol (NBD-a-Toc) synthesized in our laboratory, a fluorescence resonance energy transfer (FRET) assay was developed to monitor the kinetics of ligand transfer by a-hTTP in lipid vesicles. Preliminary results implied that NBD-a-Toe simply diffused from 6-His-a-hTTP to acceptor membranes since the kinetics of transfer were not responsive to a variety of conditions tested. After a series of trouble shooting experiments, we identified a minor contaminant, E coli. outer membrane porin F (OmpF) that co-purified with 6-His-a-hTTP from the metal affinity column as the source of the problem. In order to completely avoid OmpF contamination, a GST -a-hTTP fusion protein was purified from a glutathione agarose column followed by an on-column thrombin digestion to remove the GST tag. We then demonstrated that a-hTTP utilizes a collisional mechanism to deliver its ligand. Furthennore, a higher rate of a-tocopherol transfer to small unilamellar vesicles (SUV s) versus large unilamellar vesicles (LUV s) indicated that transfer is sensitive to membrane curvature. These findings suggest that ahTTP mediated a-Toc transfer is dominated by the hydrophobic nature of a-hTTP and the packing density of phospholipid head groups within acceptor membranes. Based on the calculated free energy change (dG) when a protein is transferred from water to the lipid bilayer, a model was generated to predict the orientation of a-hTTP when it interacts with lipid membranes. Guided by this model, several hydrophobic residues expected to penetrate deeply into the bilayer hydrophobic core, were mutated to either aspartate or alanine. Utilizing dual polarization interferometry and size exclusion vesicle binding assays, we identified the key residues for membrane binding to be F 165, F 169 and 1202. In addition, the rates of ligand transfer of the u-TTP mutants were directly correlated to their membrane binding capabilities, indicating that membrane binding was likely the rate limiting step in u-TTP mediated transfer of u-Toc. The propensity of u-TTP for highly curved membrane provides a connection to its colocalization with u-Toc in late endosomes.
    • Mediated Masculinities: The Forms of Masculinity in American Genre Film, 1990-1999

      McDonald, Terrance H.; Interdisciplinary Humanities Program
      This dissertation mobilizes Brinkema's radical formalism (2014) through Deleuze and Spinoza to read masculinities as forms. Specifically, I closely read Western films and masculine crisis films from 1990 to 1999 to map how cinematic forms constitute the potential to alter normative modes of masculinity. To launch this endeavor, I rely on a theoretical hybrid of Brinkema-Deleuze-Spinoza that foregrounds genre films as vibrant forms of difference. This foregrounding unfolds through an engagement with Altman's theory of film genre (1999), Neale's work on genre films (2000), and Grant's view of film genres as iconography and ideology (2007) as well as the work of Deleyto (2012) and Herzog (2010 and 2012) to re-conceptualize film genre in relation to form. I proceed to use my theoretical hybrid and attention to forms to interrogate film theory as a means of seizing gender and, moreover, masculinities from discourses of representation and spectatorship, which tend to limit readings of gender and masculinities to socio-cultural and political meanings. This interrogation engages Mulvey's revision of screen theory (1975), Rodowick's work on difference (1991, 1994), Perkins's approach to mise-en-scène (1972), Bordwell's neo-formalism and post-theory (1996, 2005, 2006), Sobchack's phenomenological approach to spectatorship and affect (1992, 2004), and del Río's Deleuzian conceptualization of affect and performance (2008). Then, with an insistence on the close reading of cinematic forms, my dissertation undertakes two case studies: the Western and the masculine crisis film cycles of the 1990s. Considering the work of Gates (2006) and Grant (2011) on masculinities in popular cinema, my close readings reveal masculinities as taking shape, assuming structures, and forming as they affect and are affected by relations and becomings. These close readings of cinematic forms generate theoretical speculation that engages masculinities studies research, including Bly (1990), Connell (1995), Kimmel (2006 and 2013), Reeser (2010), and Buchbinder (2013). Through theoretical speculation, my dissertation conceptualizes masculinities as forces of creation that materialize as forms. What is at stake in this dissertation is a methodology that denies transcendent ideals and essentialist claims of masculinity with concepts that harness the potential to continuously read masculinities as what has yet to come.
    • The Mental Representation of Visual Information

      Robitaille, Joel; Department of Psychology
      Despite working in relative independence, the working memory and imagery literatures investigate the mental representation of visual information. Recent reports investigating the neural structure and their associated functional activity responsible for the creation and maintenance of these cognitive representations suggest a significant overlap between these fields of study. Because each field has adopted methodologies that does not allow for a direct comparison of the mental representation described by their respective literatures, it is difficult to determine whether imagery and working memory representations are related. Hence, the current thesis further investigates the properties of the visual representation of visual information to bridge between the imagery and working memory fields. In a first study, I compare the psychophysical properties of simple stimuli commonly used in working memory reports with more complex objects adopted by the imagery field. In the course of three experiments, I demonstrate that the cost of stimulus complexity predominantly affects the quality of the mental representation while still providing evidence of a shared cognitive mechanism driving the formation and maintenance of these representations. In a second study, I evaluate the impact of mental rotation on these mental representations as well as whether the adoption of different paradigms, along with different performance metrics, assess the same cognitive construct. Here again, I show strong evidence in support of a common cognitive mechanism driving the performance across mental manipulation and through assessment methods. Finally, the last study attempted to track the manipulation of these visual representations by applying an encoding model to raw EEG activity. While I show evidence of the orientation-relevant activity during perception, the encoding model does not detect reliable enough activity to allow for tracking the orientation of the stimulus during retention and mental rotation. Together, this thesis provides evidence of a shared cognitive mechanism that drives visual working memory and imagery representation, but tracking these mental representations using EEG activity during manipulation remains unclear.
    • Metaphorical Interpretation: Measuring and Facilitating Growth.

      Kennerly, Catharine Ann; Department of Graduate and Undergraduate Studies in Education (Brock University, 2014-07-14)
      Abstract A total of 378 grade 9 students participated in this study to address the problem that although metaphorical literacy and thought are expected and necessary for success in junior and senior high school and beyond, metaphorical concepts and thought are not required to be explicitly taught to these students. The students were from 20 different classes from 4 levels: English language learners (ELL), school to work (SSTW), applied, and academic. All were from 7 secondary schools within a board in southern Ontario. Nine classes made up the control group and 11 classes made up the treatment group. All classes were given 3 pretests and the posttest. The treatment group was given Socratic lessons and direct instruction on metaphorical thought and expressions during 1 semester and in conjunction with their other classroom material. The pretest scores (TOLD, Peabody, preproverbs concrete, and preproverbs abstract) did not reveal any effect of gender, but the academic students had higher scores than the applied students. The SSTW student results are more variable: (a) for the TOLD test, SSTW scores were between those of the academic and applied students; (b) for Peabody scores, SSTW students’ scores are the same as academic and are greater than applied; (c) for preproverbs concrete and preproverbs abstract, the SSTW scores are not different from the applied scores. The postproverbs concrete and postproverbs abstract scores for the treatment groups also showed no effect of gender but revealed that all students who received the treatment did better on their post scores. The positive changes of the treatment group illustrate a measured movement from literal understanding to abstract understanding using direct Socratic instruction and proverbs as a medium.
    • Metarhizium robertsii interactions with Phaseolus vulgaris (Haricot Bean)

      Hu, Shasha; Department of Biological Sciences
      Metarhizium is an insect pathogenic fungus, as well as a plant root symbiont. During symbiotic interactions, it can benefit the plant by improving plant growth, antagonizing plant pathogens and herbivores, and enhancing plant tolerance to abiotic stresses. In this thesis, the interactions between Metarhizium robertsii and Phaseolus vulgaris (haricot bean) were studied from two aspects. First, a phenotypically degenerated (low conidia production) strain of Metarhizium was serially passaged through bean plant. Second, the immune responses of haricot bean during endophytic colonization were assessed. Commercial application of Metarhizium for insect biocontrol requires optimal production of conidia as infective propagules. It was demonstrated that conidial production and virulence of phenotypically degenerated Metarhizium were restored by serial passages through bean roots, as well as switchgrass roots, and wax moth larvae. A decrease in the expression of fungal DNA methyltransferase was observed in the phenotypically degenerated Metarhizium strain through bean passages. Whole genome bisulfite sequencing analysis showed differences in the distribution of differentially methylated regions in the degenerated and subsequently recovered strains. Metarhizium can antagonize the plant pathogen, Fusarium solani f. sp. phaseoli during bean root colonization. Using comprehensive plant hormone analysis, transcriptional expression, and stomatal size analysis, bean immune responses to colonization by Metarhizium and/or Fusarium were assessed. In comparison to un-inoculated bean, root colonization by Metarhizium resulted in reduction of abscisic acid (ABA), increased stomatal size, and decreased expression of plant immunity genes in bean leaves, which is different from those in bean colonized by Fusarium. Furthermore, exogenous application of ABA resulted in reduction of bean root colonization by Metarhizium but increased colonization by Fusarium, compared to corresponding plants without ABA application. Therefore, ABA was implicated in differential responses of bean plants to root colonization by Metarhizium and Fusarium. In conclusion, this thesis provided new insights into the study of the interactions between Metarhizium and haricot bean. Some novel findings were that fungal DNA methyltransferase was implicated in the recovery of phenotypically degenerated Metarhizium and a plant hormone, abscisic acid was implicated in differential interactions of endophytic colonization by Metarhizium when compared to a pathogenic interaction by Fusarium.
    • METHOXYPYRAZINES AND LADYBUG TAINT IN WINES

      Botezatu, Andreea Ioana; Department of Biological Sciences (Brock University, 2013-11-05)
      Methoxypyrazines are aroma active compounds found in many wine varietals. These compounds can be of either grape-derived nature or can be introduced into wines via Coccinellidae beetles. Regardless of their origin, methoxypyrazines can have either a beneficial role for wine quality, contributing to the specificity of certain wine varietals (Cabernet sauvignon, Cabernet franc, Sauvignon blanc) or a detrimental role, particularly at higher concentrations, resulting in overpowering green, unripe and herbaceous notes. When methoxypyrazines of exogenous nature are responsible for these unpleasant characteristics, wines are considered to be affected by what is generally known as Ladybug taint (LBT). This is work is a collection of studies seeking to create a sensitive analytical method for the detection and quantification of methoxypyrazines in wines; to investigate the role of different Coccinellidae species in the tainting of wines with LBT and identify the main compounds in ladybug tainted wines responsible for the typical green herbaceous characteristics; to determine the human detection threshold of 2,5-dimethyl-3-methoxypyrazine in wines as well as investigate its contribution to the aroma of wines; and finally to survey methoxypyrazine concentrations in a large set of wines from around the world. In the first study, an analytical method for the detection and quantitation of methoxypyrazines in wines was created and validated. The method employs multidimensional Gas Chromatography coupled with Mass Spectrometry to detect four different methoxypyrazines (2,5-dimethyl-3-methoxypyrazine, isobutyl methoxypyrazine, secbutyl methoxypyrazine and isopropyl methoxypyrazines) in wine. The low limits of detection for the compounds of interest, improved separation and isolation capabilities, good validation data, as well as the ease of use recommend this method as a good alternative to the existing analytical methods for methoxypyrazine detection in wine. In the second study the capacity of two Coccinellidae species, found in many wine regions – Harmonia axyridis and Coccinella septempunctata - to taint wines is evaluated. Coccinella septempunctata is shown to be as capable as causing LBT in wines as Harmonia axyridis. Dimethyl methoxypyrazine, previously thought to be of exogenous nature only (from Coccinellidae haemolymph), is also detected in control (untainted) wines. The main odor active compounds in LBT wines are investigated through Aroma Extract Dilution Assay. These compounds are identified as isopropyl methoxypyrazine, sec- and iso- butyl methoxypyrazine. In the third study, the human detection threshold for dimethyl methoxypyrazine in wine is established to be 31 ng/L in the orthonasal modality and 70 ng/L retronasally. After wines spiked with various amounts of dimethyl methoxypyrazine are evaluated sensorally, dimethyl methoxypyrazine causes significant detrimental effects to wine aroma at a concentration of 120 ng/L. The final study examines methoxypyrazine (dimethyl methoxypyrazine, isopropyl methoxypyrazine, secbutyl methoxypyrazine and isobutyl methoxypyrazine) concentrations in 187 wines from around the world. Dimethyl methoxypyrazine is detected in the majority of the red wines tested. Data are interpreted through statistical analyses. A new measure for predicting greenness/herbaceousness in wines - methoxypyrazine “total impact factor” is proposed.
    • Mind over Matter: Exploring the Power of a Positive Body Image

      Cline, Lindsay; Applied Health Sciences Program
      This dissertation examines positive body image and its relationship with appearance-related commentary, body weight, and impression formation among young adult women. It explores how women’s unique individual experiences are constructed within social interactions. The present dissertation examined weight using a dynamic approach - weight trajectory (i.e., whether someone is gaining, losing, or maintaining weight). In study 1, body appreciation and a body image coping strategy (i.e., positive rational acceptance coping), which are characteristics associated with positive body image, were tested as mediators in the relationship between the frequency of positive appearance-related commentary and the effect elicited from those compliments. Only body appreciation produced indirect effects, as the frequency of appearance compliments only impacted the effect felt from those comments through body appreciation as the processing mechanism. In study 2, women were interviewed about their body image experiences with appearance-related commentary at differing weight trajectories. Women described how their body image was influential in filtering appearance-related commentary both while a higher and lower body weight. A more positive mindset (e.g., body acceptance), rather than weight loss, fostered positive effects from positive appearance-related commentary. Study 3 determined whether information provided about a female target’s weight trajectory and/or body image altered the participants’ impression of that target. The target described as on a weight loss trajectory compared to a weight gain trajectory was rated more favourably on certain personality and physical characteristics. Further, the target described as having a positive body image (including high self-esteem) compared to a target described as having a negative body image (including low self-esteem) was also rated more favourably on numerous personality and physical characteristics. All three studies demonstrated the value of having a positive body image both from an intrapersonal and interpersonal perspective. This has important implications for future research and body image programs designed to foster positive body image.
    • Mirroring Enzymes: The Role of H-Bonding In HQuin-BAM Catalyzed Asymmetric Aza-Henry Reactions: A DFT Study into the Reactivity, Mechanism, and Origins of Selectivity

      Taimoory, Seyedeh Maryamdokht; Department of Chemistry
      The exact mechanistic understanding of various organocatalytic systems in asymmetric reactions such as Henry and aza-Henry transformations is important for developing and designing new synthetic organocatalysts. The focus of this dissertation will be on the use of density functional theory (DFT) for studying the asymmetric aza-Henry reaction. The first part of the thesis is a detailed mechanistic investigation of a poorly understood chiral bis(amidine) (BAM) Brønsted acid catalyzed aza-Henry reaction between nitromethane and N-Boc phenylaldimine. The catalyst, in addition to acting as a Brønsted base, serves to simultaneously activate both the electrophile and the nucleophile through dual H-bonding during C-C bond formation and is thus essential for both reaction rate and selectivity. Analysis of the H-bonding interactions revealed that there was a strong preference for the formation of a homonuclear positive charge-assisted H-bond, which in turn governed the relative orientation of substrate binding. Attracted by this well-defined mechanistic investigation, the other important aspect of my PhD research addressed a detailed theoretical analysis accounting for the observed selectivity in diastereoselective versions of this reaction. A detailed inspection of the stereodetermining C-C bond forming transition states for monoalkylated nitronate addition to a range of electronically different aldimines, revealed that the origins of stereoselectivity were controlled by a delicate balance of different factors such as steric, orbital interactions, and the extent of distortion in the catalyst and substrates. The structural analysis of different substituted transition states established an interesting dependency on matching the shape and size of the catalyst (host molecule) and substrates (guest molecules) upon binding, both being key factors governing selectivity, in essence, offering an analogy to positive cooperative binding effect of catalytic enzymes and substrates in Nature. In addition, both intra-molecular (intra-host) and inter-molecular (host-guest, guest-guest) stabilizing interactions play a key role to the high π-facial selectivity. The application of dispersion-corrected functionals (i.e., ωB97X-D and B3LYP-D3) was essential for accurately modeling these stabilizing interactions, indicating the importance of dispersion effects in enantioselectivity. As a brief prelude to more extensive future studies, the influence of a triflate counterion on both reactivity and selectivity in this reaction was also addressed.
    • A Mixed-Method Study of Educator Knowledge and Practice Related to Student Socio-moral Development

      Rizzo, Kelly Joelle; Department of Graduate and Undergraduate Studies in Education (Brock University, 2014-09-22)
      The purpose of this study was to explore elementary educators’ knowledge of moral development, how this knowledge relates to their beliefs and sense of efficacy pertaining to character education practices and the socio-moral reasoning of their students. It was hypothesized that educators’ beliefs and practices related to character education would reflect their pedagogy rather than knowledge of moral development theory. It was further hypothesized that there would be differences in student socio-moral reasoning specifically the beliefs and desires that guide actions would differ based on grade and gender. This mixed-method study employing self-report questionnaires, open response vignettes, and semi-structured educator interviews yielded quantitative and qualitative data. Findings indicated socio-moral reasoning of students differed according to grade (age) and gender. Knowledge of moral development theory was found to vary among participants however some practices employed by educators did align with a social cognitive approach to moral development. Significant variables identified consistently among educator and student participants included, autonomy, social competence, sense of school community, and supportiveness. These variables, in conjunction with a sense of fairness, have been identified elsewhere as foundational to moral development (Nucci, 2009), and intrinsic motivation (Ryan & Deci, 2000) and are relevant to educators working to develop student socio-moral reasoning as an aspect of character.
    • A Mixed-Methods Efficacy Study of Teaching Adolescents to Think and Act Responsibly–The EQUIP Approach: A Narrative Filmmaking Pedagogy

      Garchinski, Christina; Department of Graduate and Undergraduate Studies in Education
      Ontario’s Ministry of Education requires Character Development to be integrated into regular subject curricula (OME, 2008), yet the initiative is devoid of clearly defined research-based strategies for implementation (Bajovic, Rizzo & Engemann, 2009). The purpose of this mixed-methods (QUAN + qual) study was to examine the effectiveness of an evidence-based multicomponent psycho-educational program: The EQUIP Approach: Teaching Adolescents to Think and Act Responsibly (DiBiase, Gibbs, Potter & Blount, 2012) as it was implemented through the pedagogical tool of Narrative filmmaking in a Technological Education course. A 2 x 2 Repeated Measures MANOVA was conducted in a sample of 102 students, aged 14-18 years (M = 16.12), to address the research questions: 1) Is there a relationship between the three dependent psychometric measures, the How I Think (HIT) questionnaire, the Social Skills Improvement System - Rating Scale (SSIS-RS), and the Socio-moral Reflection Measure–Short Form (SRM-SF); and 2) Do the groups (i.e., the group receiving The EQUIP Approach (DiBiase et al., 2012) through the narrative filmmaking pedagogy (referred to as the EQUIP-NF Group) versus the group receiving the regular method of Character Education (referred to as the Control Group) differ across the HIT, the SSIS, and the SRM-SF from pre to post-test? Qualitative interviews were analyzed to address the supporting qualitative research question: How do the thoughts, feelings, perceptions, and insights of both groups (the EQUIP-NF Group and the Control Group) explain and/or expand on the experimental results? It was found that when delivered through the narrative filmmaking pedagogy, The EQUIP Approach (DiBiase et al., 2012) was an effective psychoeducational intervention, impacting the multi-component constructs of EQUIP (i.e., reducing students’ anger inducing cognitive distortions, developing students’ moral reasoning skills, and improving social skills), while concurrently satisfying Ontario’s mandate to integrate Character Development into regular subject curriculum.
    • Mobile Books: Effect of Engagement on Students’ Motivation and Cognitive Strategy Use

      Ciampa, Katia; Department of Graduate and Undergraduate Studies in Education (Brock University, 2014-09-02)
      This mixed methods research explores the role of reading engagement in 30 grade 1 students’ motivation to read mobile electronic storybooks (eBooks) and cognitive strategies used during eBook reading. Data collection comprised motivation and parent questionnaires, behavioural observation checklists, cognitive strategies rubric, and teacher interviews. Students’ emotional engagement with and enjoyment of mobile eBooks corresponded to 4 motivational aspects of intrinsic motivation: curiosity, control, choice, and challenge. Post-intervention results indicated that most student participants enjoyed answering eBook comprehension questions and preferred eBooks to print books; by the end of the study, all had access to a mobile device at home. A majority of participants were actively engaged during mobile eBook reading sessions and persisted in answering embedded eBook comprehension questions, which together reflected students’ behavioural engagement and time-on-task during mobile reading. Students’ off-task behaviours related to iPads’ accessibility features and inherent reader-friendliness. All participants successfully answered evaluative questions requiring them to activate prior knowledge, and experienced higher levels of difficulty with making personal connections. The study highlights the importance of making school-based literacy practices relevant to students’ outside worlds, and discusses implications for teacher educators, administrators, curriculum developers, and eBook and other digital developers concerning the need for greater collaboration in order to more closely align technology resources with national curriculum expectations.
    • The Molecular Consequences of CK2-mediated Phosphorylation of the TGA2 Transcription Factor within Systemic Acquired Resistance of Arabidopsis thaliana

      Bosak, Jan; Centre for Biotechnology (Brock University, 2014-08-05)
      During infection, the model plant Arabidopsis thaliana is capable of activating long lasting defence responses both in tissue directly affected by the pathogen and in more distal tissue. Systemic acquired resistance (SAR) is a type of systemic defence response deployed against biotrophic pathogens resulting in altered plant gene expression and production of antimicrobial compounds. One such gene involved in plant defence is called pathogenesis-related 1 (PR1) and is under the control of several protein regulators. TGA II-clade transcription factors (namely TGA2) repress PR1 activity prior to infection by forming large oligomeric complexes effectively blocking gene transcription. After pathogen detection, these complexes are dispersed by a mechanism unknown until now and free TGA molecules interact with the non-expressor of pathogenesis-related gene 1 (NPR1) protein forming an activating complex enabling PR1 transcription. This study elucidates the TGA2 dissociation mechanism by introducing protein kinase CK2 into this process. This enzyme efficiently phosphorylates TGA2 resulting in two crucial events. Firstly, the DNA-binding ability of this transcription factor is completely abolished explaining how the large TGA2 complexes are quickly evicted from the PR1 promoter. Secondly, a portion of TGA2 molecules dissociate from the complexes after phosphorylation which likely makes them available for the formation of the TGA2-NPR1 activating complex. We also show that phosphorylation of a multiserine motif found within TGA2’s N terminus is responsible for the change of affinity to DNA, while modification of a single threonine in the leucine zipper domain seems to be responsible for deoligomerization. Despite the substantial changes caused by phosphorylation, TGA2 is still capable of interacting with NPR1 and these proteins together form a complex on DNA promoting PR1 transcription. Therefore, we propose a change in the current model of how PR1 is regulated by adding CK2 which targets TGA2 displacing it’s complexes from the promoter and providing solitary TGA2 molecules for assembly of the activating complex. Amino acid sequences of regions targeted by CK2 in Arabidopsis TGA2 are similar to those found in TGA2 homologs in rice and tobacco. Therefore, the molecular mechanism that we have identified may be conserved among various plants, including important crop species, adding to the significance of our findings.
    • Molecular ecology and social evolution of the eastern carpenter bee, Xylocopa virginica

      Vickruck, Jessica L; Department of Biological Sciences
      Bees are extremely valuable models in both ecology and evolutionary biology. Their link to agriculture and sensitivity to climate change make them an excellent group to examine how anthropogenic disturbance can affect how genes flow through populations. In addition, many bees demonstrate behavioural flexibility, making certain species valuable models with which to study the evolution of social groups. This thesis studies the molecular ecology and social evolution of one such bee, the eastern carpenter bee, Xylocopa virginica. As a generalist native pollinator that nests almost exclusively in milled lumber, anthropogenic disturbance and climate change have the power to drastically alter how genes flow through eastern carpenter bee populations. In addition, X. virginica is facultatively social and is an excellent organism to examine how species evolve from solitary to group living. Across their range of eastern North America, X. virginica appears to be structured into three main subpopulations: a northern group, a western group and a core group. Population genetic analyses suggest that the northern and potentially the western group represent recent range expansions. Climate data also suggest that summer and winter temperatures describe a significant amount of the genetic differentiation seen across their range. Taken together, this suggests that climate warming may have allowed eastern carpenter bees to expand their range northward. Despite nesting predominantly in disturbed areas, eastern carpenter bees have adapted to newly available habitat and appear to be thriving. This is in marked contrast to many other bee species, particularly in the genus Bombus, who appear unable to shift their ranges along with climate change. Facultatively social organisms are interesting species to study the evolution of social groups, and the remaining chapters address questions of sociality in X. virginica. I used observation nests and genetic relatedness to examined how females behave towards one another in the spring prior to the establishment of dominance hierarchies in social nests. In spring, females directed fewer aggressive behaviours and more cooperative behaviours towards familiar rather than related individuals, indicating that females use nestmate recognition rather that kin recognition when interacting with conspecifics. Overwintering groups often contain both related and unrelated individuals, indicating that many bees interacting with one another in the fall prior to overwintering may be unrelated, emphasizing the importance of recognizing nestmates. Within social carpenter bee nests three different types of female have been described: primary, secondary and tertiary. Primary females are the dominant foragers and egg layers in the nest while secondary and tertiary females appear to join a reproductive queue behind the primary. To understand the nature and flexibility of this reproductive queue I performed removal experiments across three different years. This study showed that secondary females always assumed the role of replacement primary, while tertiary females rarely opted to forage and reproduce even if they were the only female in the nest. Removal experiments demonstrated that social groups in X. virginica are complex and comprise two different reproductive strategies (breed in the current year or delay reproduction) as well as form dominance hierarchies among primary and secondary females. Several tertiary females were able to become primary or solitary females in their second summer, providing evidence for how each type of female may have evolved in social nests. Finally, I examined how competition influences the evolution and maintenance of social groups in eastern carpenter bees. In conditions of high population density significantly more social nests were present in the population, indicating that competition for limiting nesting resources drives individuals together into social groups. Within social groups relatedness was low, and siblings actually dispersed away from one another to other nests in the population, reducing competition among kin. Eastern carpenter bees appear to demonstrate an interesting evolutionary route to sociality, where very high levels of competition among kin lead to dispersal, while limited nesting substrate forces individuals back into unrelated social groups. While predicted by kin selection, social groups of this nature are previously undescribed in the Hymenoptera, and further study of eastern carpenter bees can provide novel insights into alternate routes to sociality.
    • Molybdenum (IV) imido silylamido and hydride complexes : stoichiometric and catalytic reactivity, mechanistic aspects of hydrosilation reactions

      Khalimon, Andrey Y.; Department of Chemistry (Brock University, 2011-05-17)
      This thesis describes the synthesis, structural studies, and stoichiometric and catalytic reactivity of novel Mo(IV) imido silylamide (R'N)Mo(R2)(173_RIN-SiR32-H)(PMe3)n (1: Rl = tBu, Ar', Ar; R2 = Cl; R32 = Me2, MePh, MeCl, Ph2, HPh; n = 2; 2: R' = Ar, R2 = SiH2Ph, n = 1) and hydride complexes (ArN)Mo(H)(R)(PMe3)3 (R = Cl (3), SiH2Ph (4». Compounds of type 1 were generated from (R'N)Mo(PMe3)n(L) (5: R' = tBu, Ar', Ar; L = PMe3, r/- C2H4) and chlorohydrosilanes by the imido/silane coupling approach, recently discovered in our group. The mechanism of the reaction of 5 with HSiCh to give (ArN)MoClz(PMe3)3 (8) was studied by VT NMR, which revealed the intermediacy of (ArN)MCh(172 -ArN=SiHCl)(PMe3)z (9). The imido/silyl coupling methodology was transferred to the reactions of 5 with chlorine-free hydrosilanes. This approach allowed for the isolation of a novel ,B-agostic compound (ArN)Mo(SiHzPh)(173 -NAr-SiHPhH)(PMe3) (10). The latter was found to be active in a variety of hydrosilation processes, including the rare monoaddition of PhSiH3 to benzonitrile. Stoichiometric reactions of 11 with unsaturated compounds appear to proceed via the silanimine intermediate (ArN)M(17z-ArN=SiHPh)(PMe3) (12) and, in the case of olefins and nitriles, give products of Si-C coupling, such as (ArN)Mo(R)(173 -NAr-SiHPh-CH=CHR')(PMe3) (13: R = Et, R' = H; 14: R = H, R' = Ph) and (ArN)Mo(172-NAr-SiHPh-CHR=N)(PMe3) (15). Compound 13 was also subjected to catalysis showing much improved activity in the hydrosilation of carbonyls and alkenes. Hydride complexes 3 and 4 were prepared starting from (ArN)MoCh(PMe3)3 (8). Both hydride species catalyze a diversity of hydrosilation processes that proceed via initial substrate activation but not silane addition. The proposed mechanism is supported by stoichiometric reactions of 3 and 4, kinetic NMR studies, and DFf calculations for the hydrosilation of benzaldehyde and acetone mediated by 4.
    • A Multi-Scale Molecular Dynamic Approach to the Study of the Outer Membrane of the Bacteria Psudomonas Aeruginosa PA01 and the Biocide Chlorhexidine

      Van Oosten, Brad; Department of Physics
      The introductory chapters of this thesis contains an explanation to the methods and basic theory of the molecular dynamics approach. Together with the appendix section, in which a step by step tutorial how to set up and run basic simulations using the gromacs software is presented, this thesis can serve as an introductory aid in performing molecular dynamics simulations. In the research portion of this thesis, I provide several uses for the molecular dynamics approach applied to the biocide chlorhexidine as well as the study of membranes, including a mimic of the bacteria membrane of Pseudomonas Aeruginosa PA01. The motivation for this research was previous work done in our lab which determined that chlorhexidine has a high affinity for DMPC and found the depth at which it resides in a model DMPC membrane. From this information, an all-atom representation of chlorhexidine was made, which was proven to reproduce the experimental results. While we learned much about chlorhexidine in a model DMPC membrane, this study lacked the destruction of the membrane as well as the study of chlorhexidine in a biologically relevant membrane. For these reasons coarse grained versions of the all-atom chlorhexidine models as well as a new lipopolysaccharide molecule was created. With the coarse grained model of chlorhexidine and the ability to create a bacterial membrane mimic, the study of chlorhexidine and other antibacterial agents can be further studied.
    • A Narrative Study of Patient Encounter Accounts of Physicians, Nurses, and Medical Receptionists after Two Decades of a Paradigm of Patient-Centered Care

      Akseer, Riaz; Applied Health Sciences Program (Brock University, 2014-12-02)
      Despite recent well-known advancements in patient care in the medical fields, such as patient-centeredness and evidence-based medicine and practice, there is rather less known about their effects on the particulars of clinician-patient encounters. The emphasis in clinical encounters remains mostly on treatment and diagnosis and less on communicative competency or engagement for medical professionals. The purpose of this narrative study was to explore interactive competencies in diagnostic and therapeutic encounters and intake protocols within the context of the physicians’, nurses’, and medical receptionists’ perspectives and experiences. Literature on narrative medicine, phenomenology and medicine, therapeutic relationships, cultural and communication competency, and non-Western perspectives on human communication provided the guiding theoretical frameworks for the study. Three data sets including 13 participant interviews (5 physicians, 4 nurses, and 4 medical receptionists), policy documents (physicians, nurses, and medical receptionists) and a website (Communication and Cultural Competency) were used. The researcher then engaged in triangulated analyses, including N-Vivo, manifest and latent, Mishler’s (1984, 1995) narrative elements and Charon’s (2005, 2006a, 2006b, 2013) narrative themes, in recursive, overlapping, comparative and intersected analysis strategies. A common factor affecting physicians’ relationships with their clients was limitation of time, including limited time (a) to listen, (b) to come up with a proper diagnosis, and (c) to engage in decision making in critical conditions and limited time for patients’ visits. For almost all nurse participants in the study establishing therapeutic relationships meant being compassionate and empathetic. The goals of intake protocols for the medical receptionists were about being empathetic to patients, being an attentive listener, developing rapport, and being conventionally polite to patients. Participants with the least iv amount of training and preparation (medical receptionists) appeared to be more committed to working narratively in connecting with patients and establishing human relationships as well as in listening to patients’ stories and providing support to narrow down the reason for their visit. The diagnostic and intake “success stories” regarding patient clinical encounters for other study participants were focused on a timely securing of patient information, with some acknowledgement of rapport and emapathy. Patient-centeredness emerged as a discourse practice, with ambiguous or nebulous enactment of its premises in most clinical settings.
    • Negotiating a Gendered Neo-Calvinist Pillar: Immigrant Loss, Transformation, and Lifelong Learning

      VanderVliet, Catharina F.; Department of Graduate and Undergraduate Studies in Education
      Employing a critical feminist perspective, I conducted a sociocultural analysis of the lifelong learning of Dutch neo-Calvinist women who immigrated to Canada shortly after World War II. The purpose of the research was a critique of the institutional ruling relations (schooling, religion, family, workplace) that shaped and influenced the trajectory of these women’s lifelong learning. More specifically, the inquiry included an interrogation of their Canadian schooling experience, in the context of an immigrant family life, their pillarized Dutch culture, and Calvinist religiosity. In choosing a life history methodology, the scope of the research broadened where one’s life story was juxtaposed to a theory of context. Applying this methodology, I critically analyzed structures, operations, and contestations of power in lifelong learning institutions through an exploration of the multiple contexts that shaped the lives of immigrant women. It is within that relationship that the critical feminist was possible. The life histories were not a description of the mainstream but rather were positioned to dialectically interrogate the meaning and significance of the past as it influenced the present and future. Applying a dialectic method to the participants’ life histories, 7 tensions were raised that made visible ruling relations relevant to the participants’ everyday experiences and brought awareness to the underlying contextual and ideological assumptions related to their trajectory of lifelong learning. Employing a critical feminist perspective, I examined how 3 neo-Calvinist immigrant women interpreted and negotiated the ambiguity created by cultural contradictions experienced in a Canadian context. As a researcher who herself has been shaped by this specific immigrant experience, a key attribute of life history methodology was its capacity for the researcher self to be visible in the research.
    • Neural and Behavioural Consequences of Chronic Inflammation following Spinal Cord Injury

      Allison, David; Applied Health Sciences Program
      This thesis investigated the influence of chronic inflammation on several neural/behavioural disorders following spinal cord injury (SCI) including depression, cognitive impairment, neuropathic pain, and somatic nerve deficits. Ample evidence exists to suggest that the immune system communicates with, and influences the nervous system both centrally and peripherally. Pro-inflammatory cytokines have been shown to influence the nervous system directly by altering ion channel kinetics, as well as indirectly by altering enzyme function thereby resulting in changes in critical neuroactive compounds. Proinflammatory mediators have been shown to up-regulate the enzyme indoleamine 2,3 dioxygenase (IDO) resulting in the accelerated degredation of serotonin precursor tryptophan (TRP) and increased production of TRP metabolites such as kynurenine (KYN). They have also been shown to upregulate the enzyme cyclooxygenase (COX) resulting in the increased production of pain inducing eicosanoids such as prostaglandin E2 (PGE2). Immune dysfunction in the form of chronic inflammation may therefore contribute to the severity of behavioural disorders such as depression and cognitive impairment, as well as neural disorders such neuropathic pain and somatic nerve deficits. SCI is typically associated with not only a state of chronic inflammation but also a drastically higher prevalence of each of the aforementioned neural and behavioural disorders. This makes SCI an ideal population to study the interaction between the immune and nervous systems, and assess the potential efficacy of novel treatment strategies which target the immune system for the management of such disorders. A 3-month anti-inflammatory diet was utilized as a treatment intervention for the purpose of reducing chronically elevated levels of pro-inflammatory mediators. This intervention allowed for the assessment of each of the outcome variables of interest at baseline (under an elevated inflammatory status) as well as at 1-month and 3-months during the intervention (under a reduced inflammatory state). Changes in inflammation were assessed by the quantification of serum pro (IL-1β, IL-2, IL-6, IFN-У, TNF-α, CRP) and anti-inflammatory (IL-4, IL-10, IL-1RA) cytokines. Cytokine-induced alterations in enzyme function and corresponding changes in neuroactive compounds were assessed by tryptophan (TRP), the competing amino acids phenylalanine (PHE), tyrosine (TYR), leucine (Leu), isoleucine (Ile), and valine (Val), the tryptophan metabolite kynurenine (KYN), and the pain-inducing eicosanoids prostaglandin E2 (PGE2) and leukotriene B4 (LTB4). In addition to such molecular indices, actual changes in each of the outcome variables of interest were assessed. Levels of depression were assessed by questionnaire via the Center for Epidemiological Studies Depression Scale (CES-D). Cognitive function (in the form of verbal learning) and memory was assessed via the California Verbal Learning Test (CVLT). Neuropathic pain was assessed via the Neuropathic Pain Questionnaire (NPQ). Somatic nerve function was assessed by EMG, including the assessment of nerve conduction velocity and signal amplitude in both motor and sensory nerves. The intervention significantly reduced serum concentrations of pro-inflammatory mediators in the treatment group (n=12) by 28%, while no significant change was found in the control group (n=8). Among other changes in amino acids, the most notable was that the change in the KYN/TRP ratio (an indicator of IDO activity) and the TRP/LNAA ratio (an indicator of TRP availability for serotonin synthesis) was significantly different between groups. The treatment group showed a significant reduction in scores of depression, as well as a significant reduction in sensory neuropathic pain scores. No significant changes were observed in regards to somatic nerve conduction and most indices of cognitive function (with the exception of the ability to avoid incorrect responses on the CVLT). These results may suggest a substantial role for chronic inflammation in depression and neuropathic pain following SCI and provide a potential alternative treatment strategy for the management of such intractable disorders.
    • New Pyrazole-Based Ligands and Their Complexes for Application in Transfer Hydrogenation and Hydrosilylation

      Alshakova, Iryna; Department of Chemistry
      A series of bidentate and tridentate ligands bearing pyrazolyl moiety in combination with phosphine, oxazoline, amine, and sulfide were synthesized. These ligands were applied for the synthesis of ruthenium complexes, that would be efficient in catalyzing transfer hydrogenation reaction in alcohol. From a number of obtained complexes, a mixture of two isomeric ruthenium complexes was found to be the most efficient in reduction of acetophenone and N-benzylideneaniline, as model substrates, with 2-propanol. These ruthenium complexes were successfully applied in transfer hydrogenation of nitriles, heterocyclic compounds, olefins, and alkynes. Activated esters were reduced under similar catalytic conditions when ethanol was used as a hydrogen source. These isomeric ruthenium complexes were also applied in the synthesis of secondary amines via hydrogen borrowing methodology. A number of primary amines and anilines were combined with primary alcohols under the conditions, optimized for transfer hydrogenation of nitriles, resulting in corresponding secondary amines. Furthermore, ammonium formate was used as a nitrogen source for alcohol amination. Thus, secondary and tertiary amines were obtained from primary alcohols. Another project was focused on transfer hydrogenation of carbonyl compounds with lithium isopropoxide. Addition of various ligands and small molecules was found to improve the reaction efficiency for aromatic substrates. Further studies revealed that lithium cation forms stable adduct with aromatic alcohols, while different additives help to break this interaction, thus resulting in significant improvement of the conversion to alcohols. Another strategy that was applied to improve the reaction yields was the addition of a cheap source of lithium cations, such as LiCl. Finally, a new zinc complex was synthesized and applied in the catalytic hydrosilylation of carbonyl compounds. The optimization of reaction conditions reviled that the presence of substoichiometric amounts of methanol in the system significantly accelerates the process. The reaction can proceed at very low catalyst load (down to 0.1mol%) under relatively mild reaction conditions. The substrate scope analysis showed the tolerance to carbon-carbon double bond. Thus, this procedure is efficient for the synthesis of allylic alcohols from α,β-unsaturated aldehydes and ketones.