McGill University Thèses et mémoires par auteur commençant par A

Heialy, Qutayba Hamid Al (Supervisor1)  Lire la suite

Les cellules sont l’essence de chaque organe et processus du corps humain. Leur fonctionnement est régulé par un certain nombre de facteurs, notamment la membrane cellulaire, la matrice extracellulaire (CEM) et le liquide intracellulaire. Dans le cadre de cette thèse, un modèle synthétique a été mis au point pour analyser et quantifier la matrice extracellulaire à bicouche lipidique et les interactions entre un support et la bicouche lipidique.Des films d’hydrogel composés d’acide hyaluronique (AH) ont été employés pour simuler la matrice extracellulaire ou le support par des liens de couplage chimique croisé avec l’éther diglycidique du 1,4-butanediol. Le potentiel zêta …  Lire la suite

Le broyage mécanique est une technique hors équilibre qui permet la fabricationde nouveaux alliages avec des propriétés exceptionnelles. Lors de cette recherche, unbroyeur SPEX 8000 a été utilisé pour développer une nouvelle classe denanocomposites à base d'aluminium et de magnésium. Ces nanocomposites tirent leurspécificité de leur dispersion de nanocrystaux dans une matrice amorphe. Duzirconium a été ajouté aux alliages d'aluminium et de magnésium pour promouvoirl'amorphisation. Les échantillons de poudres broyées ont été recuits à 400°C pour 1heure pour évaluer la stabilité thermique des différentes phases. Leur évolution a étécaractérisée par diffraction par rayon-X et par MEBIEDS. TI fut démontré que …  Lire la suite

In humans, it has been demonstrated that Th-2 type cytokines (interleukin (IL)-4 and IL-5) are highly expressed in bronchial biopsies from asthmatics. Our hypothesis is that a distinct cytokine response comprising Th-2 cytokines occurs during the late airway response (LR) after antigen challenge and that a different Th-1 response (interferon (IFN)-$ gamma$) is related to the absence of a physiological response after antigen challenge. We have tested this hypothesis in different strains of rats, Brown Norway (BN) rats are high IgE producers that develop LR and increased airway responsiveness after antigen challenge, whilst Sprague Dawley (SD) rats are low IgE …  Lire la suite

The subject of this thesis is a critical study of Nuru'l-Din al-Raniri's refutation of Hamzah Fansuri's mystical philosophy, based on two of Raniri's works: the Hujjatu'l-Siddiq li daf'i'l-Zindiq (Maxwell Text no. 93, Royal Asiatic Society, London), and the Tibyan fi Ma'rifati'l-Adyan (Leiden Text cod. or. 3291), both of which have been reproduced in facsimile in Voorhoeve's Twee Maleise Geschriften van Nuruddin ar-Raniri (1955); and on the works of Hamzah Fansuri containing various collections of mystical poems and two prose works: the Asraru'l-'Arifin and the Sharabu'l-'Ashiqin or Zinatu'l-Muwahhidin, all of which have been edited and transliterated into the Roman script and …  Lire la suite

Trade has been going on in the Indonesian Archipelago since ancient times, linking it with the various parts or Asia and with the Middle East and the lands of the North. In Roman times, the Alexandrian geographer Ptolemy, who flourished in the year 160 of the Christian era, mentioned for the first time an area in the Archipelago, referring to it as the 'Golden Chersonese.' This prosperous land seems now to have been identified with the Malay Peninsula. Along with trade came changing religions and various cultural elements imparting upon the people their distinctive impressions. Islam too had come via …  Lire la suite

Piccirillo, Ciriaco (Supervisor1)  Lire la suite

Khwaja, Kosar Ali (Internal/Cosupervisor2)  Lire la suite

Les véhicules sous-marins autonomes sont utilisés pour diverses tâches, notamment l’inspectiond’infrastructures, la métrologie sous-marine et l’exploration océanographique. La localisationsous-marine est une tâche difficile en raison de l’atténuation des signaux, limitant l’utilisationde récepteur du système de localisation globale (global positioning system (GPS)).Les solutions de localisation sous-marine précise utilisent fréquemment les systèmes à longuebase (long baseline (LBL)) et à ultra-courte bande (ultrashort baseline (USBL)), qui nesont pas pratiques en raison de leur longue durée de configuration et de leur coût. D’autressolutions incluent les systèmes de navigation inertielle (INSs) assisté par des lochs Doppler(DVL) de haute qualité. Les estimations d’attitude et de profondeur …  Lire la suite

Le tréhalose est un disaccharide de glucose qui fait partie du métabolisme d’organismes comme les bactéries, les plantes, les insectes et les champignons, mais il est absent chez les mammifères. Chez les champignons, le tréhalose sert de source d’énergie pour la reproduction et la croissance, alors qu’il peut conférer une protection aux cellules en conditions de stress environnemental. En plus, l’accumulation de tréhalose a été liée à la virulence chez les levures pathogènes. Normalement, la biosynthèse de tréhalose est effectuée par un complexe de protéines comprenant une tréhalose-6-phosphate synthéase, une tréhalose-6-phosphate phosphatase et des protéines régulatrices. Chez la moisissure pathogène …  Lire la suite

This study is concerned with the biodegradation of polycyclic aromatic hydrocarbons (PAHs), particularly the utilization of biological processes in the bioremediation of PAH-contaminated soils. In this regard, the effects of the contaminant bioavailability and the redox environment on the biodegradation process have been investigated. First, the mineralization of naphthalene in soil/water systems under denitrifying conditions has been studied. Results showed that naphthalene mineralization is influenced by its availability to the microbial population, which in turn is a function of the compound initial concentration, the sorption/desorption characteristics of the soil/contaminant complex and the organic content of the soil. Second, the biodegradation …  Lire la suite

The sorption/desorption behavior in soil/water systems of $ sp{14}$C-radiolabeled naphthalene and nine of its nitrogen-substituted derivatives; quinoline, isoquinoline, quinoxaline, 1-aminonaphthalene, 2-aminonaphthalene, 1-amino-2-methylnaphthalene, 1-nitronaphthalene, 2-nitronaphthalene and 1-nitro-2-methylnaphthalene were investigated with respect to their physico-chemical properties and the type of interaction they form with soil organic and mineral matter. In turn, an investigation into the effect that sorption/desorption has on the bioavailability of these organic compounds and their mineralization kinetics was conducted. The non-polar naphthalene, the slightly polar quinoxaline and the three nitronaphthalene compounds sorbed through hydrophobic interaction giving rise to linear sorption isotherms that are typical of partitioning processes in which …  Lire la suite

Groffier, Ethel (Supervisor)  Lire la suite

Zeng, Haibo (Supervisor2)  Lire la suite

Blockade of the renin-angiotensin system lowers the rate of cardiovascular events in patients at risk for vascular disease and also improves endothelial function but the mechanism remains unclear. HUVECs were stimulated with Ang II (100 nM). Ang II produced a 2-fold increase in O2- production, which was measured by lucigenin-enhanced chemiluminescence. This increase was blocked by NAD(P)H oxidase inhibitor DPI, but not by eNOS inhibitor L-NAME. Ang II increased monocyte adhesion to ECs by 4.5-fold, and this increase was blocked by candesartan (AT1 receptor antagonist), DPI, L-NAME, wortmannin (PI3K inhibitor), dominant negative-AKT, and p22phox siRNA. Dominant active-AKT increased adhesion by …  Lire la suite

Leishmania is a protozoan parasite that causes leishmaniasis, infecting millions of individuals every year. The parasites utilize different virulence factors to camouflage their presence from macrophages and promote their survival. In recent years, evidence has emerged for the role of exosomes as virulence factors. Co-inoculating mice and macrophages with L. major exosomes exacerbate infections and increase parasite load. Our lab recently identified a potential role of Formyl Peptide Receptor 2 (FPR2) in exosome-mediated exacerbation of L. major infections. Hence, in this thesis, we investigate the interaction between FPR2 and L. major exosomes, and we evaluate downstream signaling pathways activated by …  Lire la suite

To define the role of mitochondrial glycerol-3-phosphate dehydrogenase (EC 1.1.99.5; mGPD) in energy balance and intermediary metabolism, we studied female transgenic mice lacking the mGPD gene (mGPD-/-). These mice had higher serum glycerol and triglycerides; lower body weight, blood glucose, and energy expenditure (QO2); and higher glycerol-3-phosphate and lactate/pyruvate ratio in muscle than controls with wild type genotype (WT). When given a high fat/low carbohydrate diet, mGPD-/- mice gain more weight than WT, without the genotype differentially affecting QO2 or calorie intake. On a low fat/high carbohydrate diet, mGPD-/- mice failed to increase QO2 as the WT and gained more …  Lire la suite

In the light of new studies of physico-chemical analysis, fabric, and particle interaction, the consideration of the actual constitution of the soil media is required for actual prediction of the soil media performance under loads. This study has been restricted to the prediction of clay performance under compression loading. A micromechanics approach has been used in this research; a microelement scale has been introduced and a set of formulations (i.e., stress transfer, fluid flow equation, and volumetric constitutive equation) has been developed for this scale. The passage from the microelement to the global scale has been established by using evolution …  Lire la suite

From 1991 to 1994 inclusively, a field and laboratory study was undertaken on egg parasitoids of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) to determine their potential in controlling their host. Five species were found to parasitize Lygus eggs in southwestern Quebec. They were three mymarids: Anaphes iole Girault, Polynema pratensiphagum (Walley), and Erythmelus miridiphagus Dozier (Mymaridae) and two scelionids: Telenomus nysivorus Huggert and Telenomus n.sp. (a new species near strelzovi Vasiliev) (Scelionidae). The maximum levels of field parasitism by these parasitoids were 20, 70, 35, and 70% (for both species of Telenomus), respectively. The field parasitism was …  Lire la suite

This thesis is made of two parts. In the first part, we study pattern formations and dissipation of energy and matter by using hyperbolic reaction-diffusion equations for reacting systems. Two-dimensional hyperbolic reaction-diffusion equations are numerically solved for the Selkov model and the Brusselator. It is shown that the evolution equations used can give rise to various kinds of patterns such as hexagonal structures, stripes, maze structures, chaotic structures, etc., depending on the values of the reaction-diffusion number and the initial and boundary conditions. The values of the entropy production computed indicate that the system maintains the particular organized local structures …  Lire la suite

Le but premier de cette recherché est de développer un procédé de traitement des poussières volatiles dangereuses permettant de les rendrent stables face à l'environnement et utiles pour des applications industrielles, structurales et décoratives. Le procédé retenu transforme les poussières volatiles en matériaux vitraux céramiques. Il implique la fusion des poussières en laitier en les exposant à un traitement à 1500°C durant deux heures, suivi d'une trempe à l'eau. Les produits amorphes obtenus sont ensuite traités thermiquement de façon à induire nucléation et cristallisation. Le traitement thermique développé fut basé sur les résultats d'analyse thermique effectués sur les produits amorphes …  Lire la suite

Shao, Yixin (Supervisor1)  Lire la suite

Shao, Yixin (Supervisor1)  Lire la suite

The response of in vitro-grown Solanum tuberosum L., cvs. Russet Burbank (RB) (salt-sensitive) and Sierra (S) (salt-tolerant) potatoes was investigated when [NaCl] was increased from 0 to 80 mM in the presence of 6, 20, and 30 mM [K] in a Murashige and Skoog (MS) basal medium. The tested growth parameters, Mg and Ca content, and K+/Na + ratios in the laminae and the roots were negatively affected as [NaCl] increased. The salt stress was relatively severe on growth of RB plants whereas the salt-tolerant (S) variety was affected to a lesser extent. There were indications that Na in the …  Lire la suite

Berk, D. (Supervisor)  Lire la suite

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals are often present together at contaminated sites. These sites are considered difficult to clean-up using bioremediation technologies because of the toxicity of heavy metals to microorganisms. Laboratory experiments were conducted to verify if biodegradation of a model PAH, naphthalene, could be sustained over a long time-period (weeks) in the presence of a common heavy metal contaminant, Cr (VI). Complete reduction of Cr (VI) at concentrations up to 6.3 mg/L was achieved by Pseudomonas putida ATCC 17484 in the presence of naphthalene that was continuously released from an immiscible organic liquid, 2,2,4,4,6,8,8-heptamethylnonane (HMN). The …  Lire la suite

Medulloblastoma (MB) represents approximately 1% of adult brain tumours, and as such is a poorly studied disease. It exhibits different clinical manifestations and outcome in adults, yet it is still treated as per pediatric protocols. Recently, gene expression profiling studies suggested the existence of at least 4 molecular subtypes in pediatric MB, characterized by distinct genetic profiles, activation of oncogenic pathways and varied clinical outcomes. This has refined our ability to classify MB, select tumors for targeted therapy and is leading the way to individualized medicine. It is unknown whether adult MB has its unique molecular signature and whether biologic …  Lire la suite

The present study was carried out to evaluate the osteoconductive nature of Bio-OssRTM (natural deproteinized bone mineral) when used as an onlay bone substitute in a Guided Bone Regeneration model. The lateral surface of the mandible was exposed bilaterally, in 8 rabbits. On one side of the mandible, two titanium chambers were filled with Bio-OssRTM material and the chambers were then firmly secured to the mandible using screws. The pores in the titanium chambers were covered with a layer of Bio-GideRTM material. On the opposite side of the mandible, chambers without Bio-OssRTM were placed on the lateral side of the …  Lire la suite

La contamination bactérienne de titane (Ti) implants est une cause majeure d'infections péri-implantaires et l'insuffisance éventuelle implant, un problème qui pourrait affecter presque 5 millions de patients chaque année dans le monde entier. Beaucoup de techniques de décontamination d'implants ont été évalués pour gérer ces infections. Par contre, ils présentent tous les résultats cliniques incompatibles surtout quand il vient à la réalisation complète re-ostéointégration. Le manque de connaissances sur l'effet des techniques disponibles sur les contaminants implant pourrait être la raison de ces résultats imprévisibles. Nous émettons l'hypothèse que, bien que ces techniques puissent être utiles dans l'élimination des bactéries, …  Lire la suite

Contexte : Les oscillomètres commerciaux comme le tremoFlo® C-100 sont indiqués pour les adultes et les enfants de deux ans ou plus - aucun appareil n'existe pour les nourrissons. Le tremoFlo® C-100 a été modifié pour permettre son utilisation chez ces derniers, ce qui a mené au développement du tremoFlo® N-100 Airwave Oscillometry System™.Objectifs : 1. Valider le système tremoFlo® N-100 en comparant ses mesures spectrales d'impédance respiratoire (Zrs) (de résistance (Rrs) et de réactance (Xrs)) avec celles du dispositif OSC de référence actuelle pour les nourrissons, l'oscillomètre Wave-tube. 2. Identifier les modèles intra-respiration physiologiquement significatifs de la mécanique respiratoire …  Lire la suite

The kinetics of deposition of clay particles in packed beds of pulp fibers is investigated theoretically and experimentally for different operating conditions that might be encountered in the industry. A theoretical model is developed to predict the clay concentration within and at the exit of the bed. The bed is modeled by the plug flow model together with Langmuir kinetics; the solution is integrated over the residence time distribution function which is specified by the mathematical solution of the axial dispersion plug flow model. A stimulus response experiment was performed to measure the real residence time distribution of the fluid …  Lire la suite

Van De Ven, T. G. M. (Supervisor)  Lire la suite

Paidoussis, Michael P. (Supervisor)  Lire la suite

Kaartinen, Mari Tuulia (Internal/Supervisor)  Lire la suite

Recently, various proteoglycans (PGs) have been identified in the lung. The first objective of this thesis was to test the hypothesis that matrix glycosaminoglycans contribute to lung tissue viscoelasticity. Lung parenchymal strips were exposed to specific glycosaminoglycans-degradating enzymes to determine whether the mechanical properties of the tissue were affected. The degradation of heparan sulphate and chondroitin/dermatan sulphate glycosaminoglycans caused significant increases in energy dissipation and dynamic resistance relative to control strips. Hyaluronidase treatment did not alter any of the dynamic or static measures. Since PGs were found to be part of the stress bearing structure, the second part of the …  Lire la suite

Objective. The objective of this study is to test the efficacy of the biodegradable mesh as an alternative fixation device to the titanium mesh for support of onlay particulate, bone and cancellous, marrow (PBCM) grafts. Two parameters were evaluated: (1) Bone graft volume maintenance; and (2) Calcified tissue surface area and distribution. Methods. 12 New Zealand white rabbits were used and divided equally into two groups. In both groups, endochondral, cancellous bone graft was harvested from the anterior ilium. The bone graft was then compressed and placed as an onlay onto the lateral aspect of the mandible using two chambers …  Lire la suite

Patients suffering from severe COPD encounter frequent episodes of exacerbations. The anatomical continuity between the oral cavity and the lung makes it a potential reservoir for respiratory pathogens that could be aspirated and cause the exacerbations. The objective of this pilot study was to determine the association between the oral health, oral hygiene in particular and the frequency of exacerbations. The study included 55 patients with severe COPD. Data were collected using various questionnaires and examinations. The results showed that poor oral hygiene was correlated significantly with the increase in number of exacerbations. There was a trend towards bad oral …  Lire la suite

Sinclair, David Stewart (Internal/Supervisor)  Lire la suite

In recent years there has been considerable interest in the development of microwave-based food processing technologies. Microwave radiation is considered to have both thermal and non-thermal effects. The thermal effects are related to the heat generated by the absorption of microwave energy by water or by organic molecules, but very little is known about the mechanisms involved in the putative non-thermal effects. It has been postulated that the latter could involve a direct energy transfer from the electromagnetic field to the vibrational modes of macromolecules, altering their conformation. In the present study, the non-thermal effects induced upon irradiation of protein …  Lire la suite

In this thesis, I propose tunable mid-Infrared (IR) sources based on the soliton self frequencyshift (SSFS) and supercontinuum (SC) generation in As2Se3 microwires. First, Ipresent two methods to maximize the SSFS in microwires with diameter profiles varyingnon-uniformly along the soliton propagation path. There are two steps in each method.The first step consists in selecting the input microwire diameter that leads to the highestrate of soliton frequency shift per unit length. The second step consists of graduallyincreasing the microwire diameter along the soliton path such that a wavelength-shiftingsoliton experiences only weak perturbations from the third-order dispersion and avoidsshedding its energy into …  Lire la suite

Hydrolysis and adsorption-desorption reaction of pyrophosphate (PP) and orthophosphate (OP) were studied in two Quebec soils (St. Bernard and Dalhousie) and three minerals (goethite, kaolinite, and montmorillonite). Soil and soil mineral samples were fractionated by size into two separates. Soil and goethite samples adsorbed more OP than PP whereas kaolinite and montmorillonite adsorbed similar amounts of OP and PP. Pyrophosphate and orthophosphate adsorption was found to be related significantly to extractable Fe. Furthermore, kaolinite and montmorillonite desorbed similar amounts of OP and PP whereas more OP than PP was desorbed from soil and goethite samples. Moreover, adsorption of OP and …  Lire la suite

In this study, alpha-Galactosidase (alpha-D-galactoside-galactohydrolase, EC 3.2.1.22) has been isolated, purified, and characterized from intracellular fraction of Lactobacillus helveticus ATCC 10797. It was purified by a combination of ammonium sulfate precipitation and fast performance liquid chromatography system using ion exchange and gel-filtration columns. This enzyme was purified to only 9.44 fold over the crude extract with a recovery of 1.8%. The km of 3.83 mM and Vmax of 416.44 mumol/min/mg protein were calculated from PNPG. The molecular mass was estimated to be 188 kDa by gel-filtration, but 90 kDa by SDS-PAGE, indicating two similar molecular weight subunits. The optimum temperature …  Lire la suite

Lung transplantation is a therapeutic option for patients affected with end-stage lung diseases. However, several complications may arise following the procedure, such as Bronchiolitis Obliterans (BO). This condition, characterized by small airway fibrosis, remains a major cause of morbidity and mortality in patients following lung transplantation. It is thought to be a manifestation of chronic rejection within the airways, with hallmark inflammation and fibroproliferation. TGF-beta and other cytokines, including IL-1, IFN-gamma and PDGF, have been implicated in the pathogenesis of fibrosis, mostly in animal models. IL-11 and IL-17 are novel profibrotic cytokines that induce fibroblasts and epithelial cells to produce …  Lire la suite