McGill University Thèses et mémoires par auteur commençant par A

Franco, Eduardo L F (Internal/Cosupervisor2)  Lire la suite

Le cancer gastrique (CG) est l’une des maladies dont l’incidence en Amérique du Nord est toujours en forte progression. Il est le 4ème le cancer le plus fréquent et la 2ème cause principale de décès lié au cancer dans le monde entier. Le péritoine est le site le plus fréquent de récurrence de CG après résection curative et est la principale cause de décès. Une fois que la métastase péritonéale (MP) se produit, le cas est jugé non traitable car les schémas chirurgicaux et chimiothérapeutiques ne sont qu’à des fins palliatives. L’ascite maligne (AM) est une caractéristique commune du CG …  Lire la suite

Objective: The purpose of this study is to test the osteoconductivity of Bone Ceramic® (BC) alloplastic material when used as an onlay graft under biodegradable poly L-lactide, polyglycolide acid (PLA/PGA) chambers (Inion® GTR , Finland). Materials and Methods: 11 New Zealand white rabbits were used. On each rabbit's mandible, one test sample (BC chamber) was placed on the (right or left) body, while its control sample (empty, E chamber) was placed on the contralateral side. Randomized placement of the test and control samples to the right and left bodies of the mandibles was applied and identified. Twelve weeks postoperatively, the …  Lire la suite

Résumé Introduction: La régénération des défauts osseux de « taille critique » reste un défi clinique. La régénération tissulaire osseuse (BTE) apparaît comme une alternative prometteuse au greffe d'os autogène, allogénique, xénogénique ou synthétique. Un défaut de taille critique mandibulaire est caractérisé par une perte de continuité de la mandibule, et est le résultat d'une résection segmentaire. De plus, le défaut mandibulaire de taille critique peut entraîner un handicap fonctionnel dévastateur, une déformation cosmétique et des effets psychologiques. L'échafaudage idéal pour la régénéra-tion tissulaire est un échafaudage qui possède les propriétés biologiques et matérielles. Objectif: La présente étude consiste à …  Lire la suite

La maltraitance infantile est une préoccupation de santé publique majeure. Chez les enfants et les adultes, des antécédents de maltraitance infantile ont systématiquement été associés à des altérations structurelles et fonctionnelles au niveau des régions fronto-limbiques du cerveau. Alors que ces altérations structurelles et fonctionnelles sont bien caractérisées, les mécanismes moléculaires par lesquels les expériences négatives vécues durant l’enfance influencent la santé mentale à long terme demeurent peu compris. L’enfance est une période critique durant laquelle le cerveau présente une plus grande plasticité ainsi qu’une sensibilité accrue à l’environnement. De plus en plus de données suggèrent que des mécanismes épigénétiques, …  Lire la suite

Objective. Most biomarker studies of maternal smoking have been based on a single blood or urinary cotinine value, which is inadequate in capturing maternal tobacco exposure over the entire pregnancy. This thesis used maternal hair biomarkers to investigate the association between maternal active and passive smoking, and birthweight for gestational age (BW for GA). Methods. Subjects were 444 term controls drawn from 5,337 participants of a multi-centre nested case-control study of preterm birth in Montreal. Maternal hair, collected after delivery, was measured for average nicotine and cotinine concentration across the pregnancy, assuming hair growth of 1 cm/month. The BW for …  Lire la suite

Les femmes souffrant des maladies chroniques font face à une choix difficile quand elles deviennent enceintes: continuer leur traitement pharmaceutique malgré les risques tératogènes, ou arrêter le traitement bien que la maladie non soignée puisse provoquer des problèmes de santé aussi bien chez la mère que chez l’enfant. Malheureusement, très peu est connu sur la consommation de médicaments sur ordonnance pendant la grossesse chez les femmes nécessitant un traitement pharmaceutique avant la grossesse. Une des raisons pouvant expliquer ce manque de connaissances est la rareté des données provenant d’études représentatives de la population qui permettent d’étudier les conséquences de la …  Lire la suite

The influences of some environmental and genetic factors on the incidence of abnormal test-days in milk-recorded cows enrolled in the Quebec Dairy Herd Analysis Service (QDHAS) was determined in this study. Conditions Affecting Records (CAR) codes, collected monthly by QDHAS's supervisors, are possible explanation for a reduced production in the day of test. For the purpose of this study, CAR codes were used to analyze the incidence of health problems under generalized linear models methodology. Poisson and logistic regression model analyses were able to model the number of cases of abnormal test-days and health problems per lactation. Herd, testing program, …  Lire la suite

Fish skin has many important functions: In addition to its ability to provide protection and a mean to carry inside organs, it plays a significant role in altering the overall flexural stiffness of the body. This combination of stiffness and flexibility allows some fishes to use the ‘exo-tendon effect’ to enhance their locomotion and to swim faster. In this mechanism, the dermis and the scales both contribute to the storing and recoiling of elastic energy during undulatory locomotion. In this work, the question of whether we can build an exoskeleton based on fish skin to assist humans was investigated. An …  Lire la suite

La migration vers les zones urbaines atteindra 68% de la population mondiale en 2050, selon les estimations de l'ONU (Nations, 2018). Il est impératif de maintenir des réseaux de distribution d'eau durables afin d’acheminer de l'eau propre jusqu'aux consommateurs et garantir la santé publique. De plus, les réseaux de distribution d'eau sont des infrastructures indispensables. La sûreté structurelle de ces réseaux de distribution d'eau est nécessaire quant à garantir que l'eau traitée ne s'infiltre pas dans le sol. Concevoir les facteurs qui affectent les performances opérationnelles d'un système de distribution d'eau peut aider à ordonner la maintenance et à prévoir …  Lire la suite

The accumulation of eosinophils at sites of inflammation is one of the hallmarks of asthma. The aim of the present study was to investigate the involvement of PGD2 and the DP1 and DP2 receptors in eosinophil recruitment in vivo. In this project, a group of Brown Norway rats were administered intratracheally with PGD2, which activates both DP1 and DP2 receptors, as well as selective agonists of DP1 (BW245C) and DP2 (15R-methyl-PGD 2 and 13,14-dihydro-15-oxo-PGD2) receptors. In addition, we have also tested the effect of 15-deoxy-Delta12,14-PGJ 2 which known to activate PPARgamma and NF-kappaB, and DP2 receptors. Negative control animals received …  Lire la suite

Emami, Elham (Supervisor2)  Lire la suite

Schuster, Tibor (Supervisor2)  Lire la suite

The travelling salesman problem is one of the NP-complete problems. It has been under consideration in computer science for at least forty years. Solving this hard problem using search methods can be accomplished by choosing: a starting point, a solution generation scheme and a termination rule. When the termination rule is such that search stops if and only if the tour is optimal, we call the method "exact". When the termination rule is such that the search stops but not necessarily with an optimal tour, we call the method "approximate". This thesis looks closely at one of the approximate methods, …  Lire la suite

Semantic trees have served as a theoretical tool for confirming the unsatisfiability of clauses in first-order predicate logic, but it has seemed impractical to use them in practice. In this thesis we experimentally investigated the practicality of generating semantic trees for proofs of unsatisfiability. We considered two ways of generating semantic trees. First, we looked at semantic trees generated using the canonical enumeration of atoms from the Herbrand base of the given clauses. Then, we considered semantic trees generated by selectively choosing the atoms from the Herbrand base using an improved semantic tree generator, AISTG. A comparison was made between …  Lire la suite

Perrault, Helene (Supervisor)  Lire la suite

Ferri, Lorenzo Edwin (Internal/Supervisor)  Lire la suite

Daniel, Sam Joseph (Internal/Supervisor)  Lire la suite

The purpose of this study was to develop, implement and evaluate a self-evaluation instrument that students would be able to use to assess their metacognitive awareness of volleyball skill and knowledge. The Self Evaluation in Volleyball Questionnaire (SEV) was designed to include a series of self-evaluation items within the five areas identified in a knowledge-based approach to skill acquisition; namely: procedural, declarative, affective, metacognitive knowledge and metacognitive skill. The reliability, face and content validity of the SEV were found to be very acceptable. The scores on the SEV show that the questionnaire was easily understood by the students, but the …  Lire la suite

Inferences about the prospective state of natural and man-made systems play a major role in designing better infrastructure and assessing the resiliency of current ones. The rapid change of such systems' responses prompts the urgent need to re-evaluate our understanding of the evolution of such systems. New predictive analytics are, hence, important for all energy, water and earth aspects of sustainable infrastructure. Ensemble learning, a branch of artificial intelligence, ushers innovative modeling approaches which are recent advancements in machine learning. According to a predefined ensemble architecture, a number of machine learners are generated and their inferences are integrated to produce …  Lire la suite

In brain mapping, the regions of the brain that are 'activated' by a task or external stimulus are detected by thresholding an image of test statistics. Often the experiment is repeated on several different subjects or for several different stimuli on the same subject, and the researcher is interested in the common points in the brain where 'activation' occurs in all test statistic images. The conjunction is thus defined as those points in the brain that show 'activation' in all images. We are interested in which parts of the conjunction are noise, and which show true activation in all test …  Lire la suite

Females and males have different sets of sex chromosomes and produce different levels of gonadal sex hormones. They also differ in many aspects of their anatomy and physiology, susceptibility to disease, drug metabolism, gene expression levels, and DNA methylation patterns. The liver is a sexually dimorphic organ showing major sex differences in steroid and drug metabolism profiles, as well as sex differences in gene expression and DNA methylation. We have recently generated a catalogue of sex-biased differentially methylated regions (sDMRs) for mouse liver and demonstrated that sex-chromosome complement and the sex phenotype influence autosomal DNA methylation. The mechanisms by which …  Lire la suite

Nonribosomal peptide synthetases (NRPSs) are large multimodular enzymes that synthesize a wide variety of different natural products. Natural products of NRPSs include toxins, metal chelators, and many medications. These products are made from a wide variety of monomer substrates. NRPSs are arranged modularly, with each module adding a monomer unit to the growing peptide chain. A typical NRPS module consists of a condensation (C), an adenylation (A), and a peptidyl carrier protein (PCP) domain. The A domain activates the substrate, the PCP domain transports the substrate, and the C domain catalyzes the formation of a peptide bond. The peptide or …  Lire la suite

In most food applications, whey proteins are used, rather than the individual proteins and this accounts for the high functional variability among commercially available whey protein products, and limits their applications. The overall objective of this study was to investigate the structural and thermal properties of individual alpha-lactalbumin (alpha-Lac) and beta-lactoglobulin (beta-Lg) fractions isolated from different whey protein sources. A common non-chromatographic process that isolate alpha-Lac and beta-Lg, with relatively high purity and yield from liquid whey (LW), whey protein concentrate (WPC) and whey protein isolate (WPI) using different chelating agents, was developed. The use of sodium citrate (NaC) and …  Lire la suite

L'effet BOLD (blood oxygenation level dependent) est l'une des plus récentes techniques d'imagerie par résonance magnetique (IRM) utilisée pour identifier les changements localisés d'activité cérébrale. Le signal BOLD varie en fonction de la circulation sanguine cérébrale (CBF), du taux métabolique cérébral de la consommation d'oxygène (CMRO2), et du volume sanguin cérébral (CBV). Les changements normalement-couplés de ces paramètres physiologiques lors d'une augmentation régionale d'activité neurale causeront une augmentation du signal BOLD. Cela rend le signal BOLD utile comme outil pour identifier les régions d'augmentation de l'activité neuronale. Deplus, le signal BOLD permet de déterminer quels changements neurophysiologiques suivent certains stimulus …  Lire la suite

Levesque, Ives (Supervisor2)  Lire la suite

Cyclic depsipeptides, ubiquitous natural products of industrial and medical importance, are produced by nonribosomal peptide synthetases (NRPS) using a diverse repertoire of biosynthetic mechanisms. For instance, cereulide (Ces) and valinomycin (Vlm) depsipeptide synthetases generate a linear precursor by the alternate condensation of hydroxy and amino acids. Hydroxy acids are added by specialized modules consisting of adenylation (A), ketoreductase (KR) and peptidyl carrier protein (PCP) domains, while an iterative thioesterase (TE) domain catalyzes the oligomerization/cyclization of the linear precursor to release the mature product.In order to perform a biochemical characterization of the specialized modules that add hydroxy acids in the Ces …  Lire la suite

Thermal conductivity is a powerful tool to probe the phonon and electron exitations in a solid, especially in superconductors were one can basically tune the respective electronic and phononic contributions by applying a magnetic field below Tc. After a short review on the concepts of superconductivity, thermal conductivity and amorphous matter, we present a study of the thermal conductivity of an exotic material, the amorphous metallic superconductor Fe0.5Ni 0.5Zr2. The results indicate an unexpected dominant electonic contribution to the thermal conductivity across the superconducting transition, in accordance with an inhomogeneous sample composed of a bulk normal phase with inhomogeneous superconducting …  Lire la suite

Introduction Le but de ce projet de recherche est d'évaluer la courbe d'apprentissage des compétences en urétéroscopie souple pour l'extraction de calculs en utilisant le simulateur UroMentorTM, ainsi que d'évaluer le transfert de ces compétences en salle opératoire. Méthodes Après avoir obtenu l'approbation éthique, des stagiaires postdoctoraux en urologie de la 1ere à la 4e année de résidence ont participé à l'étude. L'étude a été réalisée en deux phases. Pendant la phase I, les participants ont complété trois sessions de formation d'une heure par semaine sur le simulateur UroMentorTM pour s'entraîner à la Tâche 10. Dans cette tâche, deux pierres …  Lire la suite

Shrier, Ian (Supervisor2)  Lire la suite

Multiple sclerosis (MS) is a common cause of disability in young adults. Currently, around 93,000 Canadians are living with the disease and the prevalence is increasing in Canada and worldwide. MS course and clinical features vary from one individual to another and are based on type. Mobility limitations are reported in early MS and progress over the years with walking difficulties perceived as the most challenging sequela. The importance of walking limitations in defining progression of MS has raised a suggestion of using gait changes for earlier detection of disease progression. Although the Expanded Disability Status Scale (EDSS) - a …  Lire la suite

Artificial conversion of solar energy into chemical fuels is one approach to overcoming the forecasted energy famine. The main challenge facing the development of artificial photosynthesis technology is to achieve highly efficient and stable solar-to-fuel conversion. A critical component of this technology is the exploitation of various semiconductor photocatalysts that can lead to high efficiency and stable solar-to-fuel conversion. Metal-nitride nanowire structures have recently emerged as a material of choice for solar-to-fuel conversion. Compared to conventional oxide-based photoelectrodes, metal-nitride nanowires offer several distinct advantages, including a tunable energy bandgap across nearly the entire solar spectrum, conduction and valence band edges …  Lire la suite

Introduction: La plate-forme NeuroTouch est un simulateur de réalité virtuelle avec retour de force haptique, qui peuvent être utilisées pour évaluer les performances neurochirurgie dans un environnement expérimental. La validité de ce simulateur est critique à la réalisation de l'objectif de l'utilisation de ce simulateur neurochirurgical dans la formation, l'évaluation et l'élaboration de programmes d'enseignement.Méthodes: Cette étude a été menée pour évaluer les performances bimanuelles de résidents et groupes de consultants resecting une variété de simulé tumeurs cérébrales avec purge et complexité différente. Treize des métriques ont été évalués, notamment: distance totale parcourue par la pointe de l'aspirateur à ultrasons …  Lire la suite

The lungs, the main organs of the respiratory system, are constantly exposed to the external environment. Exposure to noxious agents in inhaled air can include inhaled pathogens as well as air pollution that is caused by different factors such as cigarette smoke. Cigarette Smoke (CS) exposure has been linked to numerous diseases with no cure and limited therapeutic options; this includes chronic obstructive pulmonary disease (COPD) and more recently COVID-19. Persistent exposure to CS induces inflammation in several cell types found in the lung, such as epithelial cells, fibroblasts and alveolar macrophages. This inflammation is characterized by secretion of inflammatory …  Lire la suite

La bronchopneumopathie chronique obstructive (BPCO) est une maladie respiratoire grave caractérisée par une obstruction lente et progressive des voies aériennes entrainant une gêne respiratoire. La BPCO débute par une inflammation chronique dans les poumons due à une augmentation de nombre des cellules immunitaires et de l’expression de cytokines inflammatoires (ex : l'interleukine-8 (IL-8) et la cyclooxygénase-2 (COX-2)). Dans cette étude nous avons voulu étudier si une protéine nommée antigène humain R (HuR), connue d’avoir un rôle inflammatoire, est impliquée dans le développement de la BPCO. HuR est une protéine qui se lie à l'ARN messager (ARNm) et augment sa stabilité …  Lire la suite

Let S be a data set of n points in Rd, and m&d4; be a point in Rd which "best" describes S. Since the term "best" is subjective, there exist several definitions for finding m&d4; . However, it is generally agreed that such a definition, or estimator of location, should have certain statistical properties which make it robust. Most estimators of location assign a depth value to any point in Rd and define m&d4; to be a point with maximum depth. Here, new results are presented concerning the computational complexity of estimators of location. We prove that in R2 the …  Lire la suite

This thesis contains new results on the subject of polygonal structure reconfiguration. Specifically, the types of structures considered here are polygons, polygonal chains, triangulations, and polyhedral surfaces. A sequence of vertices (points), successively joined by straight edges, is a polygonal chain. If the sequence is cyclic, then the object is a polygon. A planar triangulation is a set of vertices with a, maximal number of non-crossing straight edges joining them. A polyhedral surface is a three-dimensional structure consisting of flat polygonal faces that are joined by common edges. For each of these structures there exist several methods of reconfiguration. Any …  Lire la suite

Many writers, including Cameron (1938), and Linton (1897) have shown the necessity of studying the parasites of freshwater fishes. Cameron (1938) pointed out, that Canada, with its one-eighth million square miles of freshwater, has an extremely valuable population of commercial and game fish which harbour parasites of both medical and veterinary importance. [...]  Lire la suite

In this thesis we focus on the "Kantorovich Inequality": {t prime At cdot t prime A sp{-1}t} over({t prime t) sp2}} le {{( lambda sb1+ lambda sb{n}) sp2} over {4 lambda sb1 lambda sb{n}}}, here t is a real $n times 1$ vector and A is a real $n times n$ symmetric positive definite matrix, with $ lambda sb1$ and $ lambda sb{n},$ respectively, its (fixed) largest and smallest, necessarily positive, eigenvalues. We begin the thesis with five different proofs of the Kantorovich Inequality and continue by showing that it is equivalent to five closely related inequalities due, respectively, to …  Lire la suite

The efficiency of estimation procedures and the validity of testing procedures in simple and multiple quantitative linear models with autocorrelated errors have been studied in this thesis. The importance of the nature of the explanatory variable(s), fixed and trended versus purely random or following a first-order autoregressive [AR(1)] process, has been emphasized in Monte Carlo studies. The estimation procedures were compared on the basis of different measures of efficiency, relative to OLS or GLS, depending on the context. The estimation procedures studied include the Ordinary Least Squares (OLS), Generalized Least Squares (GLS), estimated GLS, Maximum Likelihood (ML), Restricted Maximum Likelihood …  Lire la suite

The virus-inducible Type I interferon (IFN) genes serve as relevant models to examine the nature of cis-acting sequences and trans-acting protein factors involved in transcription control. The alpha and beta interferon genes are activated differentially depending on the nature of the inducer and the specific cellular background. A transient expression system was developed to analyze the activation of the interferon promoters in a homologous human cellular background. In epithelial cells, the IFN-$ beta$ but not the IFN-$ alpha$1 promoter was virus responsive with induction kinetics similar to that of the endogenous IFN-$ beta$ gene. Expression from the IFN-$ alpha$1 promoter …  Lire la suite

Mouland, Andrew J (Supervisor2)  Lire la suite

The emergence of multidrug resistance is a serious medical problem that has significantly affected the treatment of tumor cells and infectious diseases. This multidrug resistance phenotype is mediated by the action of a large family of membrane proteins that act as active transporters or energy driven efflux pumps in both of prokaryotic and eukaryotic cells. Most eukaryotic multidrug efflux pumps belong to the ATP binding cassette (ABC) family of transport proteins that include P-glycoprotein (P-gp1), Multidrug Resistance Associated Protein (MRP1), and Breast Cancer Resistance Protein (BCRP). In prokaryotic cells, Lactococcus lactis LmrA, a homolog of P-gp1, mediates drug resistance to …  Lire la suite

McKee, Marc D. (Supervisor2)  Lire la suite

Les caloducs par gravité (CG) sont des thermosiphons biphasés (liquide-vapeur), entraînés par gravité, sans mèche, construits en évacuant d’abord puis en remplissant un tube droit fermé avec une quantité appropriée d’un fluide de travail. L’apport de chaleur à la partie inférieure du tube (évaporateur) provoque l’évaporation de la phase liquide du fluide de travail; la vapeur produite (dont la densité est considérablement inférieure à celle du liquide) se déplace vers le haut par l’évaporateur et la section centrale (efficacement adiabatique), puis se condense dans la partie supérieure refroidie du tube (condenseur); le condensat liquide retourne le long de la surface …  Lire la suite

Phan Ha-Nam Nguyen (Internal/Cosupervisor2)  Lire la suite