Crude gliadins were extracted from Canada Western Red Spring (CWRS) wheat flour with 70% (v/v) aqueous ethanol solutions and then lyophilized. Lyophilized crude gliadins were dissolved in 70% (v/v) aqueous ethanol (EtOH) or 4 mM acetic acid (HAc) and the density and ultrasound properties were measured at 20 °C. Good linear relationships of density, ultrasound velocity and ultrasound attenuation with solution concentrations were found. Solvent and sonication effects on the crude gliadins were discussed in terms of the values of the partial specific volume and the partial specific adiabatic compressibility coefficient for crude gliadins. The ethanol soluble crude gliadins had a larger partial specific volume and larger partial specific adiabatic compressibility coefficient than those for acidic soluble crude gliadins. These large values for the physical properties of ethanol soluble crude gliadins were thought to be evidence for the existence of complexes formed by some proteins (ethanol soluble LMW-glutenins and gliadins) and lipids in ethanol solutions and it was also found that the protein-lipid complexes were not destroyed by sonication treatment. Besides, there was no evidence showing that gliadins change with different wheat flours and cause different volume and compressibility properties of crude gliadins.

Introduction: The ideal timing to initiate orthodontic treatment is an important, yet controversial issue. The purpose of this study was to investigate the provision of orthodontic care for 7 types of skeletal dysplasia by paediatric dentists and orthodontists in Canada. Methods: A questionnaire was distributed to randomly selected orthodontists (N=140) and paediatric dentists (N=132) throughout Canada. Surveys returned within 8 weeks were included for c2 statistical analysis. Results: The response rate was 59% for orthodontists and 54% for pediatric dentists. Orthodontists and pediatric dentists differed significantly in the timing of their first orthodontic consultation (p < 0.01). More pediatric dentists used to the dental age to determine the appropriate time to initiate treatment (p < 0.01), whereas more orthodontists relied on the pubertal indicators (p < 0.01). More orthodontists would intervene in the early mixed dentition for moderate mandibular prognathia (p < 0.01); mid-mixed dentition for severe mandibular retrognathia (p < 0.01), late mixed dentition for moderate mandibular retrognathia (p < 0.01) and permanent dentition for skeletal openbite and severe mandibular prognathia (p < 0.01). Most pediatric dentists would intervene in the early and mid-mixed dentition for the specified cases of skeletal malocclusions (p < 0.05). Conclusions: The results of this investigation indicate both consistencies and variation between orthodontic and paediatric practitioners with regard to preference in treatment timing, and the factors that influence these decisions.

Purpose: To evaluate the in vitro shear bond strength (SBS) of orthodontic attachments using 2 self-etching primers (SEP): iBOND and G-Bond. Methods: 180 molars were randomly divided into 12 groups. Teeth were bonded with a stainless steel button using Transbond XT composite. The bonding agents were iBOND, G-Bond, Transbond Plus SEP and Transbond XT primer (control). SBS’s immediately, 24hours and 3months were measured with their Adhesive Remnant Index (ARI). Results: Transbond XT primer (11.22MPa) had a significantly higher immediate SBS than Transbond Plus SEP (5.32MPa), iBOND (6.69MPa) and G-Bond (8.30MPa). 24 hours, Transbond XT primer (16.65MPa) and Transbond Plus SEP (13.20MPa) had a significant increase in their SBS. No difference was observed at 3 months. ARI were significantly different between the groups at all time points. Conclusions: iBOND and G-Bond yielded sufficient SBS’s over the three time points that may be sufficient to withstand occlusal and light archwire forces.

Objective: To collect data regarding Canadian laypersons perceptions of smile esthetics and compare these data to US data in order to evaluate cultural differences. Methods: Using Adobe® Photoshop® 7, a digital image of a posed smile of a sexually ambiguous lower face was prepared so that hard and soft tissue could be manipulated to alter Buccal Corridor (BC), Gingival display (GD), Occlusal Cant (OC), Maxillary Midline to Face Discrepancy (MMFD) and Lateral Central Gingival Discrepancy (LCGD). Adult Canadian laypersons (n=103) completed an interactive computer-based survey of 29 randomized images to compare smile preferences for these variable. The custom survey was developed to display fluid, continuously appearing modifiable smile variables using MATLAB® R2008 for presentation. These data were compared to previously published data for US laypersons. Statistical inference was determined using Wilcoxon Rank Sum tests. Results: Canadian laypersons were more sensitive in detecting deviations from ideal and had a narrower range of acceptability thresholds for BC, GD, OC, MMFD and LCGD. Ideal esthetic values were significantly different only for BC. Conclusions: It appears cultural differences do exist related to smile characteristics. Clinically significant differences in the preference of the smile characteristics were found between Canadian and US laypersons. Canadian laypersons, on average, were more discriminating to deviations from ideal and had a narrower range of acceptability.

Overhead transmission lines are prone to undergo large amplitude, low frequency vibrations when exposed to freezing rain and steady side winds. These vibrations are referred to as galloping. They involve a dominant vertical motion in addition to twisting and horizontal swaying. Field reports indicate that the majority of galloping cases are associated with lightly-iced lines with thin ice accretions. Previous studies have failed to explain this trend satisfactorily. The present thesis involves a series of wind tunnel experiments to understand the rotational effects in lightly-iced transmission line galloping. The work to restore and upgrade the wind tunnel used for the experiments are also reported. Aerodynamic loads are measured first on a stationary model of a short, representative section of a lightly-iced conductor. Subsequently, automated controls force the model to undergo rotational oscillations, and the aerodynamic loads measured from these dynamic tests are compared to the stationary results. The airflow in both sets of experiments is visualised by using a laser-based system. The stationary test shows that the well-established den Hartog criterion for predicting vertical galloping does not explain why lightly-iced lines gallop. The dynamic experiments however confirm the presence of rotation-induced lift, unaccounted for by quasi-steady theory and the den Hartog criterion. This additional lift force increases the coupling between the rotational and vertical directions and may promote coupled aerodynamic instability. Visualisations indicate that the surface irregularities of the ice and the rotational motion are jointly responsible for the rotation-induced lift forces observed in the aerodynamic measurements.

Fourteen varieties of wheat grown in western Canada were assessed for differences in starch content and structure. Physicochemical properties of starch such as amylopectin to amylose ratio, starch granule morphology, and thermal and pasting properties were all found to vary significantly between varieties. Enzymatic susceptibility was measured using industrial α-amylase to hydrolyze gelatinized starches and resultant reducing sugar content ranged from ~407−500mg glucose equivalents per gram starch, indicating different patterns of oligosaccharide chain lengths present after hydrolysis. During fermentation striking differences in glucose generation were observed, the high glucose cohort averaged 1.21 g/g-starch for the initial time point, compared to a range of 0.83−1.05 g/g-starch for the low glucose cohort. In general, the pattern of glucose generation appears to be consistent with ethanol and biomass production. Correlating structural attributes with fermentation performance suggests that amylopectin to amylose ratio is the most predictive factor in the pattern of wheat starch hydrolysis.

Atmospheric icing is a major design factor for guyed lattice masts and transmission lines in Canada and many others countries with cold climate. Tall and slender guyed lattice towers are particularly sensitive to ice accretion, wind or combination of both, as they are often located in remote areas, where meteorological data are limited. The variation of local topography and seasonal climate affects icing conditions and complicates standardization of icing accretion design guidelines. Icing design criteria was evaluated in this study through an extensive literature review of current design standards for latticed structures subjected to ice and wind load and/or a combination of both, field and laboratory work.

Evolutionary relationships amongst strains of the fungal genus Leptographium and related taxa were inferred using the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA repeat. To generate robust sequence alignments for phylogenetic analysis the relationship between DNA sequence variability and RNA structural conservation of ITS segments was examined. The results demonstrate that structural conservation of helical regions is facilitated by compensatory base changes, compensating insertions/deletions, and, possibly, RNA strand slippage. A high mol % G+C bias for ITS1 and ITS2 and structural constraints at the RNA level appear to limit the types of changes observed. Fifty strains of Leptographium were screened for the presence of introns within mitochondrial genes. Superimposing intron survey data onto the ITS-derived phylogenetic tree reveals that introns are absent from the small ribosomal RNA (rns) gene of all strains of L. procerum yet are found in all strains of L. lundbergii. Amongst members of L. wingfieldii, L. terebrantis, and L. truncatum intron distribution is stochastic and is not correlated to the evolutionary relationships amongst strains. A group II intron/LAGLIDADG homing endonuclease gene (HEG) composite element from the mt rns gene of L. truncatum strain CBS929.85 was characterized. Intron-catalyzed splicing was tested using ORF-less and ORF-containing precursor transcripts, and both versions of the intron readily self-splice under moderate temperature and ionic conditions (37 °C and 6 mM MgCl2). Cleavage activity of the intron-encoded protein (I-LtrII) was tested using an N-terminal His6-tagged and near native protein. The homing endonuclease cleaves double-stranded DNA 2 nucleotides upstream of the intron insertion site within the exon, generating 4 nucleotide 3’ OH overhangs. Intron splicing is not enhanced by the addition of I-LtrII and RNA-binding assays indicate that the His6-tagged protein does not bind to the intron. Phylogenetic relationships amongst the rns gene, intron, and amino acid sequences were inferred. An evolutionary model of the composite element is proposed in which the HEG invaded a group II intron and mobilized it. The mobile genetic element may be transmitted vertically amongst L. lundbergii strains and horizontally through lateral gene transfer amongst strains of L. wingfieldii, L. terebrantis, and L. truncatum.

Immune activation is increasingly recognized as a critical element of HIV infection and pathogenesis, causing expansion of virus founder populations at the mucosal port of entry and eventual exhaustion of cellular immune effectors. A cohort of HIV-resistant (HIV-R) commercial sex workers (CSW) in Nairobi, Kenya, have increased levels of anti- inflammatory factors in vaginal secretions and reduced peripheral immune activation ("immune quiescence"). The mucosal immune micro-environment underlying HIV susceptibility is well-known to be influenced by concurrent sexually transmitted infections, however the role of commensal microbiota is poorly characterized. Bacterial vaginosis (BV), characterized by a shift from Lactobacillus to Gardnerella and Prevotella as dominant members of vaginal microbiota, is a risk factor for HIV acquisition in studies worldwide. However, the etiology and ecological dynamics of BV remain enigmatic, and the mechanisms by which BV increases HIV susceptibility are not fully defined. Protective functional characteristics of Lactobacillus microbiota, including acid and hydrogen peroxide (H2O2) production, may reinforce physicochemical defences of vaginal mucus, stimulate innate epithelial defences and/or modulate activation status of HIV target cells. Therefore, the goal of this study was to determine if reduced BV and increased Lactobacillus colonization are the basis for resistance to HIV in this cohort. Vaginal specimens from a group of 242 CSW were examined, including microscopic diagnosis of BV, culture-based functional analyses and phylogenetic profiling by ultra-deep sequencing. HIV-R individuals were just as likely to have BV compared to other HIV- negative (HIV-N) individuals, and no more likely to be colonized with acid- or H2O2- ii producing bacteria, however two BV-related phylotypes identified by deep sequencing were significantly more likely to be observed in HIV-N individuals (p=0.0002 and p=0.006). HIV+ individuals were significantly more likely than HIV– individuals to have E. coli detected by deep sequencing (p<0.0001) and less likely to have Lactobacillus crispatus (p=0.0006). A coherent set of differences in culture-based and culture- independent characteristics were observed in individuals with BV diagnoses compared to BV– individuals. This study has generated an unprecedented amount of information regarding the composition, structure and function of the vaginal microbiota in African CSW, fundamentally defining many aspects of BV microbiology. Elucidation of the relationship between complex microbial communities and protective mucosal responses against HIV infection should be a priority for future research.

The goals of the thesis were to, in pig models, (1) assess manganese-enhanced magnetic resonance imaging (MEMRI) in the characterization of acute and chronic ischemia-induced myocardial infarction (MI), (2) characterize cryoinjury-induced MI with contrast-enhanced MRI and optical methods, and (3) observe the effects of locally released angiogenic factors on the repair of cryoinjury-induced MI. Firstly, after acute MI was established by occlusion of the coronary artery branches, the pig hearts were isolated and mounted onto an ex vivo perfusion system inside a 7T magnet. After administration of MnCl2, T1-weighted MR images showed gradual enhancement of signal intensity within the normal myocardium, whereas the ischemic counterpart remained hypointense. During chronic MI progression, the intensity increased slowly after exposure to MnCl2 within the infarcted myocardium. Secondly, a new MI model was tested via direct 2-min contact of left ventricular epicardium with a liquid nitrogen-cooled aluminum bar. Subsequent in vivo Gd-enhanced MRI showed a uniform hypointense area (~10 mm in depth) surrounded by a hyperintense rim. Histology showed erythrocytes embolism within the cryolesion with a thin necrotic rim neighboring the normal myocardium. Four weeks later, the cryoinjured myocardium was replaced by scar tissue. Thirdly, in vivo MEMRI was tested on this cryoinjury model. After intravenous administration of MnCl2 via intermittent bolus or continuous infusion, normal myocardium showed prolonged hyperintense, which led to significant signal contrast between it and cryoinjured myocardium. Continuous infusion scheme minimized hemodynamic fluctuation. Finally, angiogenic therapy was assessed by anchoring of vascular growth factors-loaded alginate beads or adipose-derived stem cells (ADSCs)-loaded agarose patch on top of the cryoinjured myocardium. Gd-enhanced MRI revealed (1) growth of new tissue wrapping the growth factors-loaded alginate beads and (2) higher perfusion within the ADSCs-treated cryoinjured myocardium as compared with the growth factors-treated counterpart. Histological and fluorescent microsphere examination revealed that ADSCs induced more significant growth of mature microvasculature within the cryoinjured myocardium. These results indicate that MnCl2 could characterize MI ex vivo and in vivo. Epicardial implantation of ADSCs-loaded agarose hydrogel can induce angiogenesis within the cryoinjured myocardium, a form of MI with similar progression features as that induced by ischemia.