McGill University Thèses et mémoires par auteur commençant par A

Apoptosis, a mechanism for modulating tissue growth, is triggered by signals (Fas ligand (FasL), tumor necrosis factor-alpha (TNF-alpha)) derived from other cells as well as external factors such as ultraviolet radiation (UV). We have investigated the possibility that FasL, Fas, M-CSF and flt3/flk2 ligand are released on shed vesicles from HuT 78 cells, tumor cell lines (MIP-101 and CX-1), and Chinese hamster ovary (CHO) cells transfected with cDNA encoding for M-CSF and flt3/flk2 ligand, respectively. Further, we examined the effects of UV-B irradiation on the capacity of CHO cells to shed vesicles per se, and on the capacity of CHO …  Lire la suite

Distinct brain regions process innocuous vibration and cutaneous heat pain. The role of these areas in the perception of pain is still a matter of debate; and the role of these areas in the mediation of memory of somatosensory stimuli is uncertain and has not been studied with brain imaging in healthy human volunteers. All experiments described here, involved an experimental design, which included a delayed-discrimination paradigm and functional magnetic resonance imaging (fMRI). In manuscript #1, we aimed at unraveling the cerebral correlates of attention and spatial localization of innocuous vibrotactile stimuli applied to the right volar surface of the …  Lire la suite

Abbott, Frances V. (Supervisor)  Lire la suite

Background: Fixed dose combination (FDC) anti-tuberculosis (TB) therapy is currently recommended to facilitate patient adherence, and prevent inadvertent or intentional mono-therapy. We have conducted a systematic review to evaluate the risk of treatment failure or relapse and acquired drug resistance, as primary outcomes, and the proportion of bacterial conversion after two months of treatment, adverse events, adherence, and treatment satisfaction, as secondary outcomes, associated with treatment of active TB using FDC or separate-drug formulations. Methods: We searched four electronic databases for randomized controlled trials and cohort studies published in any language since 1980. Results from trials that directly compared FDC …  Lire la suite

Dose predictions by Monte-Carlo (MC) techniques could alleviate the measurement load required in linac commissioning and clinical radiotherapy practice, where small or irregular electron fields are routinely encountered. In particular, this study focused on the MC calculation of cutout factors for clinical electron beams. A MC model for a Varian linac CL2300C/D was built and validated for all electron energies and applicators. A MC user code for simulation of irregular cutouts was then developed and validated. Supported by a home-developed graphical user interface, it determines in situ cutout factors and depth dose curves for arbitrarily shaped electron fields and collects …  Lire la suite

This thesis examines how electoral maps, by shaping district demographics, impact the amount of attention allocated to minority groups within parliamentary debates. Drawing on theories of dyadic representation and past work on the impact of majority-minority districts, I argue that the amount of attention individual politicians pay to minority groups in single-member districts should increase as the population of that minority group in the district increases. I test this expectation by studying three minority groups in Canada: immigrants, aboriginal people, and francophones outside of Quebec. I measure attention using dictionary-based content analysis of every word said in the House of …  Lire la suite

Crepeau, Claude (Supervisor1)  Lire la suite

Parker, William A. (Internal/Supervisor)  Lire la suite

Chimeric Antigen Receptor (CAR) T cell therapy is a relatively new anti-cancer therapeutic strategy, with several treatments already approved by the Food and Drug Administration (FDA). In this technology, a patient’s T cells are removed and genetically engineered to express cell receptors commonly found on cancer cells and act as a “living drug” when readministered into the patient. Magnetic-based cell sorting strategies have become increasingly useful for isolating the necessary T cells from patients, relying on cell specific antibodies. The increased use of antibody-based isolation of cells is surprising given the current limitations including reduction of cell viability post-isolation thereby …  Lire la suite

There is evidence to suggest that the formation of the permanent changes that constitute memory continues in the nervous system long after the period of learning has ended. Following the learning--the period of acquisition--there remains in the brain some activity that makes retention possible. The persisting activity, which is relatively easy to disturb or disrupt, serves as a template for some more stable biochemical or synaptic change. It has been thought to consist of a reverberatory activity in closed neural circuits: a reasonable but not a necessary idea, though it seems probable that it is at least part of the …  Lire la suite

The animals used in the present experiments were male hooded rats from the Royal Victoria Hospital Colony. They were from 19 to 21 days old when obtained. The rearing conditions were modeled after those of Hymovitch (1952). The “free environment” was a wooden box (30 x 60 x 6 in.) with a wire screen top. It contained a tunnel, barriers, blocks, and elevated runways. The restricted environment cages were made of stave-pipe 15 in. high and 8 in. in diameter; holes at the top and bottom admitted light and ventilation without permitting vision of the outside surroundings. A single rat …  Lire la suite

Brown, Thomas Gordon (Internal/Supervisor)  Lire la suite

Claude, Ouimet, Marie (Supervisor2)  Lire la suite

Planar optical waveguides fabricated by K$ sp+$-Na$ sp+$ ion-exchange in soda-lime glass substrates are investigated. Experimental characterizations of planar waveguide with respect to a wide range of fabrication conditions have been carried out, including detailed measurements of the refractive index anisotropy resulting from the large induced surface stresses. Parallel to this, the non-linear diffusion process of ion-exchange was simulated numerically to provide, along with the results of the characterizations, a complete description of the refractive index profile from any set of fabrication conditions. The magnitude of the maximum surface index change observed was shown theoretically to be almost entirely due …  Lire la suite

Informal caregivers (e.g., a spouse, adult child, or friend) are pivotal in assisting individuals who face health challenges including end-of-life (EOL) decisions and care. Effective communication among all involved is essential for optimal EOL-related care processes and outcomes. In Québec, English-speaking patients, and caregivers, being a linguistic minority, can encounter unique challenges due to possible language barriers . Caregiver EOL experiences in this context require further exploration.This qualitative study begins to explore EOL experiences among informal caregivers (N = 16) of a language minority group (English) in Québec, Canada where the majority is French speaking. Informal caregivers were conveniently recruited …  Lire la suite

Objective. This study investigated the effect of cycling position (upright vs. recumbent) and seat position on the oxygen cost of cycling. Experimental design. A two-factor ANOVA with repeated measures was used to examine the effect of cycling position (Monark 814E, Lifecycle 9100 R, and Lifecycle 9500 RHR ergometers) and seat position (optimum and +/-1 setting) on VO2 and HR. Participants. Subjects were 10 male physical education students (age = 24 +/- 2.1 years, height = 178.8 +/- 4.8 cm, weight = 76.2 +/- 7.8 kg). Interventions. Each subject was tested at three 5-minute workloads (55, 137, and 186 Watts) in …  Lire la suite

It is odd that in any work on economics it should be necessary to discuss the importance of studying economic change. The classical school of political economy never gave the problem a thought; to it the study of economic development was synonymous with the study of all economics itself. However, after Karl Marx there arose a completely new way of approaching this subject: phenomena were now always studied in relation to a static model, from which all element of time was removed. This method of economic analysis was so highly developed and has become so ingrained in the minds of …  Lire la suite

[...] This present work is a contribution toward the solution of the problem of the "intermediary metabolism" of steroids. Of the two methodsused, histochemical and radioactive, the latter was by far the most productive. Even when some of the results were not up to expectations, the field has been cleared for further progress. [...]  Lire la suite

Les lignanes englobent une gamme structurellement diversifiée de produits naturels polyaromatiques hautement oxygénés avec des activités biologiques importantes. Malgré leurs diversités structurelles, la biosynthèse des lignanes commence par le couplage oxydatif d'un petit nombre de propénylphénols relativement simple. Les tentatives efforts d'imiter ce couplage oxydatif ont eu les mauvais résultats de régio- et chimiosélectivité. D'autres efforts de ces composés se sont révélés efficaces et relativement diversifiables, mais ils ont souvent été développé pour accéder à une seule classe structurelle, ou produit, de lignanes et ne capitalisent pas sur la divergence de la biosynthèse.Cette thèse détaille une méthode bio-inspirée qui vise …  Lire la suite

St-Arnaud, Rene (Internal/Supervisor)  Lire la suite

Bilateral excitotoxic lesions of the ventral hippocampus in neonatal rats result in hyperlocomotion induced by dopamine agonists, and hyperresponsiveness to stress in postpubertal animals. A cortical maldevelopment has been suggested to explain the behavioral changes observed but direct evidence is lacking to support this assumption. We studied possible alterations in excitatory amino acids receptor levels in this animal model of schizophrenia. Ventral hippocampal lesion at postnatal day 7 (PD7) induced significantly increased locomotor activity after a D-amphetamine injection (1mg/kg) in PD56 and 6 month-old (PD 180) rats but not PD35 ones. In addition, behavioral deficits were observed in postpubertal rats …  Lire la suite

Depuis quelques années, de nouvelles méthodes ont été développées pour intégrer l'incertitude dans l'optimisation de la planification de la production de la vie-de-mine i.e. life-of-mine (LOM). Cette thèse se sert de deux méthodes d'optimisation stochastique : recuit simulé (RS) et programmation en nombres entiers stochastique (SIP); les deux méthodes sont programmées dans le cadre des besoins des applications d'exploitation de la simulation stochastique et modélisation d'incertitude. Pour le cas de RS, le deuxième chapitre de la thèse décris le cas d'un dépôt de cuivre où dix réalisations simulées sont suffisantes pour fournir des résultats stables d'optimisation de LOM. En outre, …  Lire la suite

Bedos, Christophe (Internal/Supervisor)  Lire la suite

Arnold, Dr. Armin  Lire la suite

This thesis focuses on transactional process involved in the construction and operation of the Kuskokwim River Salmon Management Working Group. This cooperative wildlife management mechanism gives Yup'ik commercial and subsistence fishermen and other users a direct role, with the Alaska Department of Fish and Game, in salmon management. Transactions involving participants' knowledge and values are described in three processes: (1) the establishment of a management body and its operating rules; (2) the mediation of power in decision-making; and, (3) fishery management which uses both "science" and "fishermen's knowledge." Results indicate that through cooperation in decision-making, data gathering, and other management …  Lire la suite

Cass Elliot, une des quatre chanteurs de The Mamas & The Papas, un groupe folklorique des années 1960, décédé d’une crise cardiaque à l’âge de 32. En dépit du fait qu’elle est décédée probablement d’une combinaison de l’usage récréatif de drogues, d’épuisement, et des problèmes de santé préexistantes, la idée qu’elle est décédée d’étouffement d’un sandwich au jambon est devenue populaire. C’est probablement parce qu’Elliot était la seule femme grosse dans la industrie de la musique en les années 1970. Ce projet va réexaminer la vie et l’héritage d’Elliot avec un angle de l’intersectionnalité, en particulier comment les croyances répandues …  Lire la suite

Precision of determining age in ringed seals (Phoca hispida) was examined by repeated readings of undecalcified cross sections and decalcified stained longitudinal sections of mandibular canines. There appeared to be geographical differences in repeatability although this could not be tested statistically. There was no difference in repeatability between cross and stained sections. The effect of precision on population parameters was examined. Smoothing procedures necessary to construct life tables and to do Leslie matrix calculations obscured any differences in ages between readings. Variance between readings was found to give inconsistent notions of sexual maturity. Imprecision caused little overall difference in growth …  Lire la suite

John Horne Tooke's philosophy of language is worth examining because, although his work has been influential, and although there is much of intrinsic interest in what he wrote - particularly for many of the questions discussed by philosophers recently - still, he has seldom been mentioned in English philosophical circles during this century. [...]  Lire la suite

Vitamin D is a fat-soluble vitamin that can be obtained endogenously by exposing the skin to ultraviolet beta radiation from sunlight or exogenously from food and supplements. Due to the recommendation that infants should not be exposed to sunlight, and low vitamin D content in breast milk, this age group is recommended to be given a vitamin D supplement until a sufficient amount can be obtained from their diet. The Canadian Paediatric Surveillance Program (2002-2004) estimated a total of 104 confirmed cases of vitamin D deficiency rickets, most of which were diagnosed in the north or immigrant families. From the …  Lire la suite

BackgroundHemorrhage continues to be the leading cause of death in major trauma. The concept of damage control resuscitation has gained popularity in both army and civilian setting, and early resuscitation with a high ratio plasma to packed red blood cell transfusion in a protocolized setting has been associated with improved survival, reduced complications and improved resource utilization.Research objectiveWe aim to determine if higher ratio plasma to packed red cell (FFP:PRBC) transfusion has an impact on survival in our Canadian level 1 trauma center.MethodsThis is a retrospective study incorporating all the trauma victims who received any blood transfusion in the period …  Lire la suite

Contexte: Des inégalités en santé périnatale selon le statut maternel à la naissance ont été documentées dans divers pays, dont le Canada, où les mères nées à l'étranger connaissent de meilleurs résultats périnatals que les mères nées au pays malgré leurs positions socioéconomiques relativement inférieures. Cependant, l'ampleur et la direction des inégalités varient selon les résultats, les contextes d'études et les années d'études. Dans cette étude, j'ai examiné les différences dans les issues périnatales mortelles et non mortelles entre les femmes nées au pays et à l'étranger dans un échantillon récent et représentatif à l'échelle nationale de naissances au Canada. …  Lire la suite

Despite the wide applications of powder metallurgy in the additive manufacturing (AM) technologies, the effect of powder characteristics (particle size distribution PSD, surface morphology, etc.) on the spreadability and packing factor in electron beam powder bed fusion (EB-PBF) is not well investigated. Powder spreadability and flowability are controlled by adhesive forces, friction forces (particle-particle interactions due to surface condition and topography) and coulombic forces (van der Waals forces, electrostatic and tribocharging). Currently, there are no standard procedures to measure spreadability. In this thesis, a technique has been proposed to study spreadability in which a single layer of powder is spread …  Lire la suite

Le travail actuel vise à comprendre certains des mécanismes moléculaires qui agissent sur la régulation du développement du système nerveux central (SNC). Nous nous concentrons sur le rôle d'une famille de protéines adaptatrices qui s'appelent 14-3-3. Les deux premiers chapitres sont consacrés au guidage axonal. Au cours du développement, les neurones doivent projeter leurs axones vers les cibles appropriées afin d'établir des connexions physiologiquement pertinentes. Pour se faire, les neurones doivent interpréter l'environnement moléculaire complexe dans lequel ils se trouvent, rôle qui est accompli par les cônes de croissance. Notre groupe a déjà identifié 14-3-3s, une famille de protéines adaptatrices, …  Lire la suite

Il a été démontré que les marais tempéré à eau douce sont des grandes sources de méthane, contribuant ainsi au fait que les zones humides sont la plus grande source naturelle de méthane atmosphérique. Cependant, nous avons peu de données et de compréhension de la dynamique du méthane des marais. Les objectifs de cette étude étaient de mesurer le flux de méthane (FCH4) à l'échelle de l'écosystème d'un marais tempéré d’eau douce et tenter de déterminer les moteurs de ce flux ainsi que ses voies d'émission. Le flux de méthane ainsi que le flux net de dioxyde de carbone (NEE) …  Lire la suite

A monokinetic beam of neutrons (0.07 e.v.) has been scattered by a gas, and the angular dependence of scattering measured over the range 0° to 90°. This isbelieved to be the first measurement of neutrons diffracted by gas molecules. The experiments were performed with a modified neutron crystal spectrometer using a beam of neutronsfrom the Chalk River pile. The gases studied, CO2 and O2, were at room temperature and approximately 60 atmospheres pressure. Observed intensity distributions are compared with calculated patterns. The latter are based on classical interference theory, so take no account of inelasticscattering. Good angular agreement of interference …  Lire la suite

In the nineteenth century, Cayley proved that a smooth cubic surface has exactly 27 lines over the complex field. Schläfli and others showed furthermore that the number of real lines could be 27, 15, 7, or 3. These results were found using the algebraic geometry techniques of the time. In this thesis, we solve this classic real enumeration problem using two different techniques. One method is group theoretic, and the other uses characteristic classes. Part of our goal is to show how these methods are related to each other as well as to the classical results. In particular, we give …  Lire la suite

Jakobson, Dmitry (Supervisor2)  Lire la suite

Radiobiological irradiation can be performed using appropriately collimated sealed source radioisotope machines such as Co-60 units, as well with X-ray tubes and linear accelerators. The increasing research interest in delivering organ-specific or whole body animal external irradiation has led to the introduction of dedicated X-ray units for research purposes. In this work, the proprieties of a kilovoltage X-ray biological irradiator, the Faxitron cabinet X-ray system model CP160, are investigated and dosimetrically characterized. Calculation formalisms for everyday use of the radiobiological irradiator in laboratory conditions, specifically for cell cultures and small animals total body irradiation, were developed following the AAPM TG-61 …  Lire la suite

Abstract: Introduction: Patients with triple negative breast cancer (TNBC) have the worst prognosis among all breast cancer subtypes. These patients usually receive neoadjuvant chemotherapy (NACT) with the hope of achieving pathological complete response (PCR). The vast majority of patients with pCR have an excellent prognosis similar to other breast cancer subtypes, while those without pCR relapse quickly. Nevertheless, around 10% of patients with pCR relapse and 40% without pCR have a good prognosis. Developing a more accurate biomarker of tumor genetic makeup and response to NACT will help in delivering more efficient treatment. Circulating tumor DNA (ctDNA) in plasma has …  Lire la suite

This thesis examines the trade related aspects of transborder data flows (TDF), placing TDF issues within the economic context provided by trade in services and particularly within the scope of the North American Free Trade Agreement (NAFTA). It is based on the premise that TDF are nothing but the rendering of a service product, whether final or intermediate, across national borders. Recognizing that international trade has become increasingly dependent on information exchange systems, the thesis asks whether or not NAFTA provides a solid legal framework to deal with discriminatory regulations, conflicting technical standards and protectionist measures that hamper the flow …  Lire la suite

The field of structural DNA nanotechnology utilizes DNA's powerful base-pairing molecular recognition criteria to help solve real challenges facing researchers in material science and nanotechnology, some of which include synthesis, sensing, catalysis, delivery, storage, optics, electronics, and scaffolding. In it, DNA is stripped away from any of its preconceived biological roles, and is treated as a powerful synthetic polymer. A subarea of research that our group has recently termed supramolecular DNA nanotechnology is emerging, and is proving to be a powerful complement to some of the already established rules of structural DNA nanotechnology. The work within this thesis falls under …  Lire la suite

Fackson Mwale (Internal/Supervisor)  Lire la suite

Un protocole d'établir film radiochromique dosimétrie de référence en fonction de débit de dose élevé source Ir-192 curiethérapie été évalués et décrits. Une comparaison entre les courbes d'étalonnage créé dans l'eau et Solid WaterTM sont fournis. Solid WaterTM s'est révélée être une alternative viable à l'eau dans l'établissement de la courbe d'étalonnage pour les Ir-192 faisceau de rayonnement. Un facteur de correction de Monte Carlo a été calculé pour convertir la dose à l'eau en dose à Solid WaterTM et les méthodes expérimentales que nous avons réalisé d'accord avec les résultats de Monte Carlo où le ratio (DSW/DW)Ir-192 a été …  Lire la suite