McGill University Thèses et mémoires par auteur commençant par U

Several classes of genes determine the lifespan of the nematode Caenorhabditis elegans. Our laboratory is particularly interested in the clk class of genes that is composed of clk-1, clk-2, clk-3 , and gro-1. Mutations in these genes have been shown to extend lifespan and to deregulate several developmental and behavioural processes such as pharyngeal pumping and defecation cycle length. clk-1 encodes a 187 amino acid mitochondrial protein that is composed of two homologous TRC domains (TRC for T̲andemly R̲epeated in C̲LK-1). Interestingly, the yeast homologue of clk-1, COQ7, has been implicated in ubiquinone biosynthesis. clk-1 (e2519) lesion is a point …  Read more

The world is facing an unprecedented problem with waste electronics and electrical equipment (WEEE). The amount of WEEE continues to increase annually and toxic materials used within their printed circuit components continue to leach into the environment. Existing strategies, such as recycling, have been ineffective remedies to these problems. Printed circuits based on graphene oxide (a derivative of graphene) may help solve this problem. Graphene oxide is easily recycled by dissolution in water, with the primary byproduct being humic acid – a family of compounds commonly found in natural water bogs. Historically, research on graphene oxide has been focused on …  Read more

Lettuce mosaic virus (LMV) is an economically important pathogen with worldwide distribution. LMV infection in L. sativa can cause significant yield losses. Resistance to LMV in L. sativa is conferred by the recessive gene mo. We attempted to position the mo gene on the L. sativa map. The ultimate goal is a better understanding of plant-virus interactions. To do so, Random Amplified Polymorphic DNA (RAPD) markers were screened in the near isogenic lines (NILs) Vanguard and Vanguard 75. These NILs differ in the presence of the mo gene in Vanguard 75. Polymorphic markers were screened for linkage to mo in …  Read more

Arbuscular mycorrhizal (AM) fungi have been living in association with land plants for at least 400 million years. Because they are obligate symbionts, the study of AM symbiosis has focused primarily on its plant host and progress in the molecular biology of AM fungi has been very slow. Using two different approaches, library screening and direct PCR-based assays, genetic information of AM fungi was compared across isolates and species. This allowed the study of novel DNA regions previously unexplored in AM fungi. The following species were investigated: Glomus intraradices, Glomus mosseae, Gigaspora margarita, Scutellospora calospora, Acaulospora scrobiculata and Entrophosphora colombiana. …  Read more

Hassani, F. P. (Supervisor)  Read more

Transport of oil or other hazardous substances by sea constitutes the backbone of the world economy. The fiscal benefits and dependence on the transport of oil and other substances by sea outweigh the dangers associated with the carriage of such substances by sea, especially the pollution of the marine environment. Although the absolute answer for the protection of the marine environment may be to prohibit the harm-producing activities altogether, and to turn to alternative energy-resources, it seems very unlikely that this will be the case in the near future. The feasible solution for the protection and preservation of the marine …  Read more

L’amélioration des performances electrochimiques des batteries Li-ion est déterminante pour l’atteinte des objectifs de développement durable établis par la communauté scientifique. Parmi les mesures prises en ce sens est la miniaturisation des matières électrochimiquement actives vers les dimensions nanométriques. Cependant, l’utilisation des nanotechnologies amène de nouveaux défis à l’étape de l’enduction lors de la fabrication des électrodes destinées aux batteries Li-ion; l’enduction n’est pas adaptée aux matériaux nanométriques et bidimensionnels puisque qu’elle introduit des problématiques liées à la rhéologie. Ainsi, ce projet a comme objectif d’évaluer et de concevoir une technique d’enduction alternative utilisant les principes de la déposition électrophorétique …  Read more

The high mortality rate in developing countries stemming from poverty and diseases, and the pressure on healthcare budgets in developed countries have evoked a major concern in healthcare delivery. The need for less costly and patient-centered healthcare delivery brings point-of-care testing (PoCT) to the fore. PoCT devices help to eliminate the overheads associated with centralized bench-top laboratory instruments. Although, handheld devices such as Glucose biosensor strip exist, small handheld PoCT devices for molecular techniques such as Polymerase Chain Reaction (PCR) used to provide infectious disease testing are new and emerging.Polymerase Chain Reaction (PCR) is a biological technique used to amplify …  Read more

Pollak, Michael (Supervisor2)  Read more

This thesis aims to enhance patient care for trauma laparotomy patients by focusing specifically on hospital length of stay (HLOS), a critical metric in resource-constrained healthcare systems. Although trauma laparotomy patients represent a relatively homogenous trauma cohort, they exhibit diverse needs and varied outcomes, necessitating targeted interventions. A series of studies was conducted to explore strategies, particularly the implementation of enhanced recovery protocols (ERPs), to optimize HLOS and improve patient care. Chapter 2 analyzed data from 27,434 trauma laparotomy patients in the National Trauma Data Bank, a large trauma registry in the United States, to provide a clearer understanding of …  Read more

Travis, Lisa de Mena (Internal/Supervisor)  Read more

This thesis attempts to challenge the dominant historiography in the field of Islamic law and expand our understanding to show that it is more than just the fiqh of jurists. Jurists' law, characterized as a sacred law, arguably reached its final form in the 10th Century CE as an ideal unchanging theory that is the yardstick for the application of Islamic law. Due to this alleged inability to change and its rigidity, Islamic law failed to accommodate the needs of society and proved impractical for governance and ruling authorities created their own secular legal system. This thesis attempts to overcome …  Read more

Wireless communication is highly susceptible to eavesdropping attacks where a malicious user can exploit the broadcast nature of the wireless signals to eavesdrop on confidential information. At the physical layer, there are multiple possible avenues to utilize the inherent randomness of the wireless transmission medium to achieve secure communication. One of the lucrative possibilities is to use the channel state information (CSI) to establish a secure communication link because it is vital in decoding the received signal at the transmitter. This technique is commonly referred to as discriminatory channel estimation (DCE) where the channel estimation performance is intentionally degraded at …  Read more

Rock Mechanics, as such, is a comparatively young science. It has gradually evolved from minor branches of activity in Engineering, Physics, and Geology. Today it may be considered as being a separate field of scientific endeavour. The earliest investigations into the behaviour of rocks under pressure were described over a hundred and fifty years ago. Observations related the observed phenomena to geological structures, and were qualitative rather than quantitative.  Read more

The first example of a stable triple-stranded helix consisting of exclusively T$ cdot$AT (reverse-Hoogsteen$ cdot$Watson/Crick) base triplets is reported. This approach to induce and stabilize the anti-parallel triplex involves the use of a branched oligonucleotide with two parallel dT$ sb{10}$ strands joined to riboadenosine via $2 prime$-$5 prime$ and $3 prime$-$5 prime$ phosphodiester linkages, i.e., rA$ rm sp{ lbrack 2 prime-5 prime-dT10 rbrack} sb{ lbrack3 prime-5 prime-dT10 rbrack}$ (underbar2.1). Triple helix formation by branched oligonucleotide underbar2.1 and dA$ sb{10}$ was investigated by thermal denaturation analysis, circular dichroism spectroscopy, PAGE retardation assays and fluorescent studies. A linear oligonucleotide with a loop …  Read more

Waldispuhl, Jérôme (Supervisor1)  Read more

This thesis explores the relationship between the exchange rate and the domestic price level in three essays. The first essay (Chapter 2) examines the causality between the exchange rate and consumer prices, and estimates the extent of the exchange rate pass-through to consumer prices for 12 OECD countries for the period 1974 to 2016. Using the adoption of the Euro and the adoption of the policy of targeting inflation in these countries, which represent changes in the monetary policy regime, I divide this time period into two groups and examine causality and pass-through behaviour separately for each country. Based on …  Read more

AbstractAbout 300 million tonnes of inferred Ni resource in ultramafic hosted rocks is present in 'Thompson Nickel Belt' in north central Manitoba. The processing challenges result from electrostatic interaction between pentlandite (the main Ni-mineral) and serpentine (the main gangue and one of the MgO minerals). As a contribution to meeting the challenge, the thesis examines the role of particle and bubble surface charge and the effect of fibre disintegration on flotation behavior of an ultramafic Ni ore sample. For surface charge characterization the sedimentation potential technique was used. A novel integrated device was developed to measure sedimentation potential, conductivity and …  Read more

In this study, two semi-analytical models of microsegregation were developed to predict the concentration fields of solute in the liquid and solid regions for dendritic solidification of binary metallic alloys. Both models assume that the growing dendrites are cylindrical in shape. This assumption is more realistic compared to the common assumptions of plate-like dendrites that most of the earlier researchers employed in their microsegregation modeling study. The solute redistribution profile, in the developing solid layer, necessary to determine the back diffusion parameter was derived from Fick's second law for the model without coarsening. The application of this parameter in a …  Read more

Disease resistance in a plant is a manifestation of a complex phenomenon which involves among other things, the inherent and acquired physiologic properties of not only the host but also those of the pathogen influenced by ever-changing conditions of both the macro- and micro-environment.  Read more

Experimental investigations of suggestion and suggestibility have been frequent ever since the last decade of the nineteenth century when research began almost simultaneously in the United States, France and Germany. Since then, suggestibility has been studied by workers in various fields: abnormal psychology, social psychology, sociology and individual differences. The exponents of the Nancy theory of hypnosis, who consider that the hypnotic trance is a "state of heightened suggestibility," of course studied suggestibility as an abnormal phenomenon. Murphy and Murphy (231, p.5) writing as social psychologists consider that the experimental study of suggestion marked the beginning of experimental social psychology. …  Read more

The dynamic and public nature of a large scale public distributed system introduces challenging security issues that demand new technical approaches. Existing literature has discussed a variety of schemes but fall short of describing an engineering process to design security in such systems. This thesis presents a process model for security system design in large distributed systems that are prone to unpredictable joins and departures, the possibility of malicious behaviors by public nodes and diverse local policies. A case study on designing security architecture for a Public Computing Utility (PCU) is presented which is in tune with the proposed process …  Read more

Les Peuples Autochtones du Canada sont touchés de manière disproportionnelle par l’insécurité alimentaire et de faibles résultats de santé. Des approches holistiques qui prennent en considération tous les aspects du système alimentaire sont nécessaires à la planification systémique communautaire améliorant la sécurité alimentaire. Par le biais d’une approche basée sur les systèmes alimentaires, l’objectif de cette étude était de conceptualiser un processus participatif arrimé aux visions et aux compréhensions communiques de systèmes alimentaires ancrés dans les valeurs d’une communauté autochtone dans le but de promouvoir la sécurité alimentaire, la nutrition, et le bien-être. En partenariat avec le Projet de prévention …  Read more

Par l'entremise du cadre théorique d'horizon des attentes développé par Hans Robert Jauss, cette thèse examine le type de personnage que George Gissing caractérise dans le titre de son conte "A Victim of Circumstances" (1893), et ce, dans quatre oeuvres: Bleak House (1953) de Charles Dickens, Jack (1876) d'Alphonse Daudet et de Gissing, Workers in the Dawn (1880) et Veranilda (1903). La thèse met en évidence le discours de ces écrivains sur les choix de l'individu et les circonstances déterministes. L'argument avancé dans la thèse est que ces trois romanciers de l'époque victorienne résistent couramment à une lecture simpliste qui …  Read more

This thesis is a study of one aspectual construction, the "te-i(ru)" construction, in Japanese. This construction posed a serious problem for the study of Aspect in Semantics. That is, it seems to allow two contradictory interpretations: progressive and perfect of result. We argue that the the two distinct readings are the result of the syntactic interaction of the morpheme "te", the aspectual predicate, and the aspectual auxiliary verb "i-(ru)". Adopting the framework proposed by Travis (1991, 1994), we argue that the semantic operators, "BECOME" and "CAUSE", originally proposed by Dowty (1979), are actually generated in Syntax as the aspectual predicate, …  Read more

This thesis examines the identities and the narratives of Overseas Chinese. Through discussing their history, I explore how the overseas Chinese came to imagine themselves as a community called 'Chinese Diaspora', which is ostensibly held together by the imagination of a 'homeland' in a faraway place in the distant past. By examining autobiographical texts, I discuss how the 'Chineseness' they maintained throughout the migration is founded upon such a virtual reality, and how this in turn is experienced by the individuals. Taking the narratives as something that both reflect and construct their identities, I explore the conundrum women in diaspora …  Read more

Young, Allan (Supervisor1)  Read more

The regulation of water and electrolyte metabolism has been the subject of much investigation. Many factors have been implicated, one being that volume plays a role in the regulation of sodium in the body. It has been suggested that there may be receptors somewhere in the body, which are sensitive to changes in the volume of fluid or in the concentration of electrolytes. It has not been clearly established yet whether they are sensitive to blood volume, plasma colloid osmotic pressure, interstitial fluid volume, or some other factor. The importance of the adrenal cortex in influencing sodium metabolism is well …  Read more

The importance of tile adrenal cortex in influencing sodium and potassium metabolism is well established. The adrenal cortex secretes a number of steroid hormones which affect sodium and potassium excretion to varying degrees. The hormone which is the most potent in its sodium retaining effect is aldosterone. It promotes the sodium reabsorption for the exchange of potassium or hydrogen ion in the distal tubules of the kidney. There are several problems which are not well understood, e.g. the physiological importance of the rate of secretion of various steroids, the synergistic or antagonistic action of various adrenal cortical hormones on the …  Read more

Holcomb, R. (Supervisor)  Read more

Lanthipeptides are a family of peptide natural products that contain characteristic thioether rings within their structures. These rings are post-translational modifications installed into the C-terminal region of ribosomally synthesized precursor peptides (LanAs). In class II lanthipeptides, a single enzyme (LanM) constructs these thioether rings in a multistep reaction cascade. Due to their antibiotic properties and the growing crisis of antibacterial resistance, lanthipeptides are important targets of drug development – making an understanding of their biosynthesis essential. Recently, the first crystal structure of a class II lanthipeptide synthetase (CylM) was solved, providing an opportunity to investigate potentially vital structural characteristics of …  Read more

Lanthipeptides are a family of ribosomally synthesized and post-translationally modified peptide (RiPP) natural products that originate as genetically encoded precursor peptides (LanAs) and undergo multistep modification catalyzed by lanthipeptide synthetases. Class II lanthipeptide synthetases (LanM enzymes) catalyze the dehydration of multiple serine/threonine residues in the LanA precursor peptide, followed by the intramolecular addition of cysteine thiols onto the nascent dehydration sites to construct multiple thioether bridge macrocycles. LanMs utilize two separate active sites in an iterative, yet highly coordinated manner, and maintain a remarkable level of regio- and stereochemical control over the multiple macrocyclization events. This biosynthetic fidelity is thought …  Read more

The syntheses of the cephalosporin analogs cis-N-(2'-hydroxyphenyl)-3-phenylacetamido-4-hydroxymethyl-2-azetidinone (37), cis-N-(2'-hydroxy-5'-nitrophenyl)-3-phenylacetamido-4-hydroxymethyl-2-azetidinone (59) and 7-(beta)-phenylacetamido-3'-hydroxybenzo{3,4}-0,2-isocephem (77) are described. Compounds 37 and 59 were devoid of antibacterial activity, while (beta)-lactam 77 showed weak activity against two micoorganisms. Two new ring systems, 2-phenylcarbapenams 146 and 157 have been prepared. These are key intermediates in the syntheses of phosphonic acid carbapenam 148 and the carboxylic acid derivative 158, respectively. The one carbon homologation of (beta)-trimethylsilyl-(alpha),(beta)-unsaturated esters with diazomethane was extended to the corresponding (beta)-trimethylsilyl or (beta)-t-butyldimethylsilyl aldehydes.  Read more

Ces dernières années, la marge bénéficiaire des sociétés minières a diminué en raison des prix bas des mineraux et des coûts d'exploitation élevés liés à la dégradation des ressources naturelles et au vieillissement du système, forçant les sociétés minières à réduire leurs coûts d'exploitation pour maintenir leurs activités. Les épargnes présentées par les nouvelles technologies et les ressources informatiques qui permettent aux entreprises de moderniser leurs équipements d'extraction minière sont compensées par une complexité croissante des équipements qui peut entraîner des coûts d'exploitation plus élevés. Les opérations de forage sont l'un des éléments sur lesquels peuvent porter les efforts de …  Read more

This study describes a laboratory scale development of an in-situ bioremediation method, which uses a water table management system to supply nutrients to subsoil microorganisms, for biostimulation and subsequent biodegradation of pollutants such as fertilizer-nitrate and hydrocarbons (e.g., diesel oils), in the unsaturated zone of the soil. The study, which was divided into two parts: first nitrate bioremediation and secondly diesel biodegradation, was carried out on packed soil columns. For the nitrate study, different levels of glucose were introduced into packed soil columns, 1,000 mm long x 200 mm, diameter, via subirrigation in order to supplement the organic carbon levels …  Read more

Cette thèse décrit le développement de nouvelles méthodes pour la formation sélective de liaisons C–C grâce à l’utilisation de métaux de transition comme catalyseur, dans l’optique d’accéder à de nouvelles structures moléculaires.Après une brève introduction du couplage aldéhyde-alcyne-amine (A3-coupling), le chapitre 2 présentera la modification séléctive d’acides aminés et de peptides avec les alcynes. Grâce à une nouvelle méthode inspirée du couplage-A3, les acides aminés et les dipeptides ont été fonctionalisés aux extrémités N-terminales, et sur la fonction e-amine de la lysine, avec du chlorure de cuivre(I) comme catalyseur, en haute concentration. La réaction a été appliquée à une vaste …  Read more

Divers aspects de la chimie du complexe Cr(CO)s(CS) furent examines. Une attaque nucléophile impliquant le ligand thiocarbonyle du Cr(CO)s(CS) a été obtenue avec des agents nucléophiles forts. Par exemple, la réaction avec NCO a donné [Cr(C0)5(CN)r, la réaction avec N3- a conduit à la formation de [Cr(C0)5(NCS)], et la réaction de Cr(CO)s(CS) avec Me2NH a donné Cr(CO)s[S=C(H)NMe2]. La réaction entre Cr(CO)s(CS) et d'autres nucléophiles, L, (L = Me3NO et Br-) a donné deux produits, résultant de l'attaque nucléophile du ligand CS pour le premier produit et de la reaction avec le C du carbonyle situe en position trans par rapport …  Read more

Food frequency questionnaire and 24-hour recall methods were used to assess the general consumption of leafy vegetables and fruits within the Luo of northern Tanzania. The frequency questionnaire focused specifically on the consumption of Crotalaria brevidens, a leafy vegetable in a genus characterised by toxic pyrrolizidine alkaloids. Leafy vegetables were the most frequently consumed food group, contributing 23% of the total frequency scores. Crotalaria brevidens contributed 1.7% of the total frequency scores although some individuals consume significantly more. High consumption frequency of Crotalaria sp. is negatively associated with the consumption of fruits, fats and oils, vitamin A animal sources and …  Read more

This thesis examines the politics of international legal tutelage in post-independence Kosovo by investigating the dynamics of power interplay between EU's largest civilian mission to date – EULEX and Kosovar stakeholders. Informed by the "practice turn" in IR and borrowing from Bourdieu's sociology of juridical field, the central argument of this thesis posits that the relations between EULEX as an "expertise-rich" entity and Kosovar institutions as "expertise-deficient" as well as their interactions as partners in the monopoly of violence, have resulted in the emergence of a new legal field that has been grounded by the ontological glorification surrounding the notion …  Read more

Mongrain, Rosaire (Supervisor1)  Read more

Alzheimer disease (AD) is a neurodegenerative disorder that is clinically characterized by a progressive cognitive decline and neuropathologically defined by extracellular plaques, mainly consisting of amyloid-β (Aβ) peptide aggregates, and intraneuronal misfolded phosphorylated tau forming neurofibrillary tangles. However, molecular causes of the disease and biomarkers for the detection of the disease prior to formation of plaques are still subjects of ongoing research.Aβ peptides are produced by sequential cleavage of the amyloid precursor protein (APP), firstly by the β-secretase (BACE1) then followed by the γ-secretase. This amyloidogenic pathway generates Aβ peptides of varying lengths that are subject to proteolytic degradation. BACE1 …  Read more

In human cells, histones bind DNA and form chromatin, a nucleoprotein complex important for various cellular processes. Abnormal histone modification is known to play causal roles in the development of cancer. Monocytic leukemia zinc finger protein (MOZ) is a MYST-family histone acetyltransferase whose gene is rearranged in chromosomal translocations giving rise to acute myeloid leukemia. This acetyltransferase functions as a potent transcriptional coactivator of Runx1 and Runx2, two homologous transcription factors that are important for definitive haematopoiesis and osteoblast maturation, respectively. Mouse knockouts have demonstrated that MOZ is required for the maintenance of hematopoetic stem cells, and is important for …  Read more

Les revêtements de l’oxyde métallique (MO) ont été utilisés dans plusieurs applications d’électrochimie de base, particulièrement dans l’industrie du chlore-alcalins, pour la production de produits chimiques valables (le chlore, l’hydroxyde de sodium, l’oxygène, etc.). MO ont aussi été employées à des fins d’électrodes de supercondensateurs électrochimiques et en système organique de protection contre la corrosion des métaux, d’électrodes de stimulation neuronale, de capteurs d’électrodes et traitement de gaspillage d’eau.Cette thèse de doctorat représente une tentative afin de contribuer à la zone d’électrodes de l’oxyde métallique en utilisant les couches de l’Ir/Ru-oxyde comme matériels d’électrode en quatre applications sélectionnées. Les objectifs …  Read more

This thesis presents a first study of various aspects of $K sp0$ and $ Lambda$ production in neutral current deep inelastic scattering of 27.5 GeV positrons and 820 GeV protons. The data were accumulated with the ZEUS detector at HERA in the 1994 run period. The average multiplicities for the neutral strange particle production as functions of pseudorapidity $ eta$ and transverse momentum $p sb{t}$ have been determined in the kinematic range 10 $GeV sp20.04.$ The particle and energy flow with respect to the struck quark direction, as well as the dependence of the average production rate as function of …  Read more

Depuis la fin du XIXe siècle, un groupe divers de Canadiens anglais provenant de la bourgeoisie et de la classe moyenne se sont initiés aux principes émergents de l’urbanisme. Dans cet élan, ils ont établi des liens avec une cohorte internationale de spécialistes d’urbanisme et ont diffusé les connaissances qu’ils ont acquises sur le sujet à travers le Canada. Malgré cette adhésion au monde d’urbanisme transnational et l'influence qu’elle a exercée sur l’urbanisme moderne du Canada, l’historiographie n’aborde pas la complexité des interactions canadiennes et des échanges idéologiques avec cette cohorte internationale. Cette thèse démontre que les balbutiements de l’urbanisme …  Read more

Age-related differences in the in vivo incorporation of 32-P into mouse myelin basic proteins (MBPs) of the central nervous system were observed. The resulting specific radioactivity (S.A.) of the MBPs appeared to be related to the S.A. of the acid-soluble pool of phosphates of myelin. In development, MBPs were phosphorylated in vivo prior to the onset of myelination in the brain, indicating that MBPs are phosphorylated prior to their deposition in the myelin sheath. The incorporation of 32-P into MBPs and the turnover rates of MBP phosphates were studied in vivo in developmentally-related myelin compartments. The results suggest that there …  Read more