McGill University Thèses et mémoires par auteur commençant par B

The claudin family of tight junction proteins regulates paracellular permeability, apical-basal cell polarity, and cell adhesion and their cytoplasmic C-termini interact with the actin cytoskeleton. Through these activities, claudins have the potential to coordinate cell and tissue behaviors during epithelial morphogenesis. We previously showed that a subset of claudins is differentially expressed between the neural and non-neural epithelium during neural tube closure. This led to my hypothesis that these domains of claudin expression correlate to claudin function during neural tube morphogenesis and, if true, I predicted that deleterious missense mutations in CLDN genes would contribute to increased susceptibility to human …  Lire la suite

Le cycle global du carbone (C) exerce un contrôle primordial sur la dynamique climatique à long terme de la Terre. La matière organique dissoute (MOD) dans les écosystèmes aquatiques est l'une des composantes les plus actives du cycle global du C et constitue une source vitale de C pour les microbes. On soupçonne que les terres entourant les rivières affectent la biodisponibilité et la composition de la matière organique dissoute fluviale en raison d'influences anthropogéniques telles que l'agriculture et l'urbanisation. Les bassins hydrographiques modifiés confèrent une composition différente à la MOD qui peut affecter la biodisponibilité en aval des substrats …  Lire la suite

Salmonella Enteritidis has become a major burden in human health due to emergence of multiple-antibiotic resistant strains that has made antibiotic treatment difficult. Today, there is urgency to develop efficacious alternatives to the utilization of sub-therapeutic antibiotics in poultry. We, therefore, hypothesized that, in contrast to sub-therapeutic antibiotics, mannose-rich oligosaccharides (MOS), a natural prebiotic, would improve intestinal innate defense mechanisms in healthy and Salmonella-infected chickens, and abrogate S. Enteritidis invasion of intestinal epithelium, thus mitigating Salmonella-induced intestinal and systemic inflammation. In contrast to virginiamycin (VIRG) and bacitracin (BACT) antibiotics, dietary MOS (0.2%) significantly improved intestinal innate defensive mechanisms in chickens …  Lire la suite

The potential of lignin and mannanoligosaccharides (MOS), as alternatives to antibiotic growth promoters was evaluated in broilers. Dietary treatments included: (1) negative control (CTL-, antibiotic free); (2) positive control (CTL+, 11 mg/kg virginiamycin); (3) MOS (diet 1 + Bio-Mos: 0.2% to 21 d and 0.1% thereafter); (4) LL (diet 1 + 1.25% Alcell lignin); (5) HL (diet 1 + 2.5% Alcell lignin). Bodyweight and feed conversion were not different when broilers were fed the CTL+, MOS, LL or HL diet. Birds fed MOS or LL had increased jejunum villi height (P < 0.05) and greater goblet cell number per villus …  Lire la suite

Science is for all individuals regardless of their gender, cultural background, social circumstances, or career aspirations. Yet, not all students are offered equal opportunities to perform well in science. Students with learning disabilities (LD) are continuously lagging behind in science, and scoring significantly lower grades as compared to their typically achieving peers across various settings. Research studies aiming at investigating the difficulties faced by postsecondary students with LD in learning science are sparse. It is critical that barriers experienced by students with LD are explored in order to design and implement interventions for their academic success in STEM programs. The …  Lire la suite

Two studies were conducted to investigate the effects of partially or totally replacing corn with pearl millet (PM) in broiler diets, alone or in combination with exogenous enzymes, on growth performance, ileal dry matter (DM), CP and amino acid digestibility, and intestinal digesta viscosity, morphological development and microbial populations. In experiment 1, dietary treatments included: a standard corn-soybean meal diet and one in which corn was replaced with 25, 50, 75 or 100% PM. In experiment 2, dietary treatments were: 1) a standard corn-soybean meal diet; 2) a PM-soybean meal diet; 3) diet 1 + exogenous enzymes; and 4) diet …  Lire la suite

Photochemistry is rapidly becoming one of the important fields of organic chemical research. Several recent reviews and books on the subject attest to this fact. Part of the reason for this interest is the potential value of photochemistry as a synthetic tool. For example, on a laboratory scale, many cis-trans isomerisations, valence isomerisations, skeletal rearrangements, and dimerisations have been accomplished. Many of the products of these reactions would be very difficult to obtain by nonphotochemical means. The most obvious examples of the success of photochemistry on a large scale are the irradiation of ergosterol to give vitamin D, and photosynthesis. …  Lire la suite

L'échelle au foyer est un paramètre qui relie la distance angulaire observée dans le ciel à la distance physique dans le plan focal d'un télescope. Une juste interprétation des images d'une cascade électromagnétique dans la caméra est possible uniquement si l'échelle au foyer est connue de façon précise. Une bonne compréhension des images permet de calculer les différents paramètres de la cascade, permettant ainsi de discriminer le bruit de fond de manière plus efficace et d'estimer plus précisément les propriétés du rayon gamma primaire. L'échelle au foyer des télescope s VERITAS a été calculée et simulée numériquement auparavant, mais n'a …  Lire la suite

Despite the use of measles vaccine for over 30 years, measles continues to occur even in highly vaccinated populations. The goal set by the Pan American Health Organization to eliminate measles from the Americas has not been accomplished yet. Although live-measles attenuated vaccines have dramatically reduced the incidence of measles infection, relatively little is known about the immune response generated by vaccination. The principal objective of the work described in this thesis was to perform detailed analysis of cellular and humoral responses to primary measles vaccination in children from the developed and developing worlds. Studies involving Canadian children ranging in …  Lire la suite

Du point de vue de la sécurité industrielle, les explosions représentent un risque major, en particulier pour les installations pétrochimiques et les raffineries, où les décharges accidentelles de grandes quantités de matériel inflammable peuvent se produire. Quand une explosion se produit dans ce genre d'installations, le danger le plus important est souvent une déflagration à grande échelle, qui peut produire des dommages importants à des bâtiments individuels, ou même des dommages couvrant une grande étendue, par exemple dans le cas de l'explosion non confinée d'un nuage de vapeur. A ces échelles, la formation d'instabilités de flamme augmentent de manière significative …  Lire la suite

Previous experiments, using the internal beam of the McGill University synchrocyclotron to produce delayed proton emitters, have resulted in spectra with a resolution ef 200 keV. Also no structure was seen in any of the observed delayed proton peaks. [...]  Lire la suite

Stress corrosion cracking in its simplest terms is metal failure resulting, over a period of time from the conjoint action of stress and corrosion. In reality, the problem is more involved than this definition might suggest for the reason that the two operating factors, namely, stress and corrosion do not act in a simple additive way. Stress corrosion cracking is not a mere case of metal corrosion in the presence of stress. Although it is true that corrosive attack is part of the mechanism, the extent or severity of corrosion is not a guiding criterion for susceptibility to cracking. Many …  Lire la suite

From the time that Pavlov began using the conditioned reflex method to investigate higher nervous processes in animals, there has been much controversy over the reliability of this procedure. It is hoped that the conditioned reflex method will be further justified in this report, which corroborates the work of other laboratories, and brings forward new material in agreement with results found by other methods of investigation. [...]  Lire la suite

An attempt was made to investigate the oxidation of zinc ethyl by the method of ~dilute flames". However, no flame could be obtained even at quite high temperatures and pressures. Furthermore, there was no evidence of any reaction whatever at the low pressures used. The oxidation of zinc ethyl is always accompanied by the deposition of a white precipitate,and this could not be observed. [...]  Lire la suite

Non-suicidal self-injury (NSSI) is a prevalent behaviour among high school-age youth; however, there remains confusion concerning the optimal sources of support and treatment for these adolescents. The current study sought to investigate how many adolescents with NSSI are willing to access help at school, as well as the variables related to their willingness to do so. Overall, 13.5% of the students who reported engaging in NSSI indicated that they were willing to seek help at school. The rate of help-seeking did not differ by gender or indices of NSSI severity, including the frequency of NSSI and number of body locations …  Lire la suite

When George Moore wrote these words in his preface to the revised 1904 edition of his youthful autobiography, he still had almost thirty years to live. On the other hand, he had passed all the crises of his career, domestic, financial, amorous, and literary, and was firmly on the course he was to follow all his remaining years. [...]  Lire la suite

The neurophysiology of respiration has been the subject of intensive investigation for well over a century. Early in this period it became apparent that the most fundamental respiratory centres were located within the brain stem, and that the activity of such centres was influenced directly or indirectly by humoral factors and by afferent stimuli from many sources including centres situated more rostrally in the central nervous system. [...]  Lire la suite

Jasper, H. (Supervisor)  Lire la suite

Although the secretory effect of the cervical sympathetic nerve on the submaxillary gland of the dog was established almost seventy-five years ago by Czermak, at the present time its functional relationship is still indefinitely defined. There is no doubt that the peculiar action of the sympathetic nerve made investigation of its function difficult and led to the formulation of several hypotheses to explain its action on the secretory apparatus of the salivary glands. The sympathetic nerve is the second secretory nerve supplying the salivary glands, and when it is sectioned there is very little change in the reflex salivary secretion. …  Lire la suite

This investigation was undertaken at the suggestion of Dr. Bram Rose in order to assess what happens to the histamine content of human nasal mucous membrane during allergic raction. In previous work carried out by Rose, Entin and Baxter (1951) on the histamine content of various human tissues, several high values (101 and 140 Y per gram) were obtained on antral mucous membrane from allergic individuals. The exact significance of such findings was not clear.  Lire la suite

The Merrifield method of Solid Phase peptide synthesis has been applied to a study of the evolution of the neurohypophysial hormones. This work was carried out in an attempt to establish the identity of a principle designated EOP 1 (elasmobranch oxytocin-like principle 1) which had been isolated from the pituitary gland of the spiny dogfish (Squalus acanthias), and to test hypotheses on possible evolutionary intermediates. Three new analogues, 8-glutamine-oxytocin, 8-phenylalanine-oxytocin and 4-proline 8-glutamine-oxytocin were synthesized while a fourth, 8-valineoxytocin, previously synthesized by classical methods was synthesized for the first time by solid phase. Each analogue was synthesized on the Merrifield …  Lire la suite

This research was undertaken in order to obtain some knowledge of the role of biotin in mammalian metabolism. Toward this end, preliminary gross metabolism experiements were performed in which biotin-carboxyl-carbon-14 was injected into white mice and the various tissues and excreta examind for radioactivity. In the course of these experiments, an appreciable fraction of the injected activity appeared in the expired carbon dioxide.  Lire la suite

Tait, J. (Supervisor)  Lire la suite

Very few definite facts are known concerning the role of the sympathetic nervous system in the secretory processes of the digestive glands. A certain amount of controversial data has been presented but a true understanding of the sympathetic innervation of the various digestive glands has not been reached. There are several reasons which may account for this. Investigation of the function of the sympathetic nerve supply to the digestive glands involves many experimental difficulties. In all experimental work involving stimulation of the symnpathetic nerves, the characterfstic vasoconstrictor action of these nerves is encountered. [...]  Lire la suite

Le diabète de type 1 (DT1) est une maladie auto-immune chronique caractérisée par la destruction des cellules β productrices d'insuline, nécessitant un traitement à vie par insuline exogène et imposant un fardeau considérable aux patients. La transplantation d'îlots pancréatiques est apparue comme une stratégie thérapeutique prometteuse, mais sa mise en œuvre clinique à grande échelle est limitée par la pénurie de donneurs, la faible survie à long terme des greffons et la nécessité d'une immunosuppression systémique. Pour relever ces défis, cette étude examine les propriétés immunomodulatrices de polymères modifiés à base de chitosane et d'alginate, respectivement le chitosane phosphocholine quaternisé …  Lire la suite

Three known mammalian endothelins, ET-1, ET-2, and ET-3, are each encoded by separate genes and expressed in a variety of vascular and nonvascular tissues. Two subtypes of endothelin receptors have been identified and termed endothelin-A and endothelin-B receptors (ET-A and ET-B). In the first part of this study, the ET-A gene was disrupted in mouse embryonic stem cells to generate mice deficient in ET-A. In the second part of this study, we investigated a targeted disruption of the mouse ET-B gene that results in aganglionic megacolon associated with coat color spotting, resembling a hereditary syndrome of mice, humans and other …  Lire la suite

This study seeks to analyze the Turkish nation-building process during the early Republican period (1920-1938). In doing this, the substantive focus will be on three main dimensions --language, education, and citizenship -- with particular emphasis on the rhetoric and actions of the political elite. By looking at language, education, and citizenship policies, and their formulations, the present analysis will make three main propositions: First, and in contrast to the existing literature on nations and nation-building, it will be demonstrated that the process of Turkish nation-building was neither a smooth nor an automatic process. Moreover, during the period under analysis, there …  Lire la suite

There is a strong positive association between educational attainment and health outcomes, and neighborhood and housing play central roles in relation to both (Leventhal & Brooks-Gunn, 2002; Stafford & McCarthy, 2006). The present study examined health and education-related variables across neighborhoods, as defined by housing types and administrative districts, in Ulaanbaatar, Mongolia. Based on literature establishing associations between neighborhood deprivation and adverse health and educational outcomes, and on emerging scholarship of sprawling ger districts in Ulaanbaatar, the study hypothesized neighborhood residence in ger districts (characterized by gers and single family houses) would be associated with adverse health and educational outcomes …  Lire la suite

The gait pattern during treadmill walking is comparable with overground walking in healthy subjects, but the effects due to the mode of walking in stroke subjects have not been established. Purpose. (1) To compare the maximum gait speed of stroke subjects walking on treadmill vs. the ground. (2) To estimate the temporal-distance determinants of the maximal gait speed. (3) To compare temporal distance factors and body kinematics of stroke subjects walking at comfortable vs. maximum speeds during the two modes of locomotion. Subjects. Ten subjects (aged 63 +/- 19 years) with a hemiparesis due to a stroke (<3 months) were …  Lire la suite

La maladie de Parkinson est une maladie neurodégénérative caractérisée par des symptômes moteurs résultant de la dégénération des neurones dopaminergiques dans la partie substantia nigra du cerveau. L’α-synucléine (α-syn) est le constituent majeur des corps de Lewy (Lewy bodies; LBs), des inclusions protéiques prédominants dans les patients de la maladie de Parkinson idiopathique et familiale. Ce projet doctoral investigue le mécanisme d’internalisation des fibrilles et oligomères d’α-syn impliqués dans la propagation des agrégats α-syn. Bien que des études précédentes démontrent l’endocytose dépendante de la clathrine comme mécanisme d’internalisation, nos données suggèrent qu’une macropinocytose permet l’entrée primaire et rapide des fibrilles …  Lire la suite

Quantitative microanalysis of rough surfaces is a big challenge in electron microscopy field. Although X-Ray microanalysis can be a useful tool for preliminary characterization, it is not quantitative because the geometry of rough surfaces introduces problems that are not present in the microanalysis of a bulk sample. The problem with the quantitative microanalysis of rough surfaces is that electrons can be scattered from all sides due to different slopes on the surface. Therefore, the geometry of rough surfaces impacts the generated, emitted, or measured x-ray intensities and thereby the quantitative analysis of the surface.The present Ph.D. study will focus on …  Lire la suite

The availability of long-read and long-range sequencing technologies has provided an opportunity to improve the genomic characterization of non-model but important organisms. Previously, genomic resources such as genome and transcriptome assemblies were only available for either simple organisms or model organisms such as Drosophila. In this thesis, I describe how we assembled the 480 Mb genome of the olive fruit fly (Bactrocera oleae), the most important pest in the olives agribusiness industry. We used short-, mate-pair-, long-, and linked-read sequencing technologies to generate a genome assembly (GenBank accession GCA_001188975.4) with a scaffold N50 of 4.69 Mb and L50 of 30 …  Lire la suite

Glenn, H. Patrick (Advisor)  Lire la suite

Shakespeare's history plays are not merely benign representations of various historical figures and events but the site of political, cultural, and ideological contestation at the time of their performance. Richard II documents two divergent theoretical approaches to sovereignty which are more applicable to the political climate in Shakespeare's time than Richard's. In this essay, I read this play through the lens of various political tracts and historical tendencies dominant in late Elizabethan England. Though such an analysis might best be understood as historical materialist in orientation, I offer a contextual analysis of various modes of early modern political thought drawing …  Lire la suite

La douleur telle que nous la ressentons provient de l'intégration de signaux sensoriels, cognitifs et émotionnels dans le cerveau. L'état émotionnel ainsi que l'état attentionnel influencent l'expérience de la douleur, les émotions modulant principalement la dimension déplaisante de la douleur et la distraction modulant principalement son intensité. Des odeurs et de la musique ont été utilisés afin de distraire les sujets et de manipuler leur état émotionnel, ce qui a également altérer leur perception de la douleur. D'autres données montrent qu'observer des images au contenu émotionnel, notamment des photos de visages exprimant différentes émotions, a un impact sur l'état émotionnel. …  Lire la suite

Snell, J. (Supervisors)  Lire la suite

The engaged classroom is a space where teacher and students come together to share in the acts of teaching and learning. They embark on a collaborative journey of empowerment and through the process reciprocally influence each other's growth and emancipation. Through an autobiographical exploration of my experiences as a student and as a teacher, I present an exploration of the concept of empowerment. I explore its significance not only on the level of literacy development in my kindergarten classroom, where I teach French in an Armenian heritage language setting, but also on a more personal and professional level. Working in …  Lire la suite

Hechtman, Peter (Supervisor)  Lire la suite

During the past few years a number of thorough studies have been made of immigration into Canada and the United states. These have not only revealed the quantitative movement of large numbers of people across international boundaries with the expressed intention of establishing permanent residence, but have also indicated the precise nature of the social process of immigration. The studies of’ the latter have been most profitable in bringing out the causative factors of migration and the by-productual results affecting individual personalities and the general body politic among which they seek an economic and social niche. [...]  Lire la suite

This thesis deals with the curricular development of modern languages in the schools of England between 1864 and 1918. At the beginning of the period, modern languages were fringe curricular subjects; by the end of the period, they had achieved full curricular status in the secondary schools. The vehicles for investigating the curricular development of modern languages are the reports of the Royal Commissions and Board of Education. This thesis shows that modern languages became an integral part of the liberal curriculum and hence were taught chiefly in the secondary schools as instruments of cultural and mental formation for the …  Lire la suite

La synthese endogene du cholesterol (CH) a ete etudie chez 81 nouveau-nes, ages de 4 mois (BRAS 1) ou de 11 a 12 mois (BRAS2), afin d'evaluer les effets a long terme d'un supplement de CH sur l'homeostasie du CH. BRAS 1 etait compose de 32 nouveau-nes recevant soit du lait humain (HUM) (6M, 7F), une formule a base de lait de vache (VAC) (6M, 3F) contenant 3.5 mg CH/dl, ou une formule a base de lait de vache modifiee (VACM) (6M, 7F) contenant 13.5 mg CH/dl, afin d'evaluer l'effet du supplement sur les taux de synthese du CH. BRAS2 …  Lire la suite

Des données de la typologie linguistique peuvent avoir un impact positif sur le processus d'apprentissage automatique des modèles de traitement automatique du langage naturel (TALN). Cependant, les bases de données typologiques qui existent actuellement sont composées d'informations discrètes qui n'ont pas la capacité de représenter précisément l'information linguistique. Par conséquent, ces données sont finalement inutiles. Je présente une nouvelle base de données comprenant des statistiques continues, qui peuvent ainsi mieux refléter cette information linguistique si importante  Lire la suite

The importance of discontinuous hormonal signals in endocrine communications is suggested by the ability of sustained hormonal signals to shut down, as opposed to stimulate, target cells, and by the observation that a change in pulse pattern can alter the response elicited. Serial sampling of the serum in catheterized, conscious, freely-moving rats was employed to investigate two aspects of pulsatility in the hypothalamo-pituitary-testicular feedback loop regulating reproduction in the adult male. First, in response to treatment with moderate to high doses of the testosterone (T) metabolite, dihydrotestosterone (DHT), pituitary responsiveness to exogenous LHRH was suppressed, and elevated post-castration mean LH …  Lire la suite

While mitochondria contain their own genome, more than 99% of mitochondrial proteins are nuclear-encoded, synthesized in the cytosol, and rely on mitochondrial targeting sequences (MTS) for their localization. The most common class of MTS’s are N-terminal MTS’s (N-MTS), which direct proteins through the translocases of the outer (TOM) and inner mitochondrial membranes (TIM). Upon reaching the matrix, these N-MTS’s must be cleaved off by the mitochondrial processing peptidase (MPP) for the mature protein to localize and fold correctly. Beyond these canonical import substrates, there also exist unique mitochondrial substrates that contain multiple MTS’s and rely on multiple proteases for their …  Lire la suite

Characteristics of inbred plants were sought which might indicate the maturity pattern of their F1 progeny. Observations were also made on the influence of xenia and cytoplasm from the female on ear moisture loss (of F1 kernels and plants). [...]  Lire la suite