McGill University Thèses et mémoires publiés en 2005

The verification of VLSI circuits, which are ever increasing in size and complexity, is bottlenecked during simulation within the circuit design process. Distributed simulation on a cluster of workstations or a shared memory multiple processor computer attempts a cost-effective solution. The key factor in performance of these simulations is the development of distributed simulation algorithms that make use of the circuits' underlying properties. This study presents the design and implementation of a distributed simulation framework to better produce and test simulation algorithms. The framework includes a technique to generate circuits, since large commercial circuits are hard to obtain, a Verilog …  Lire la suite

The term patina refers to a particular quality of decay in material objects, where the decay is both a physical and symbolic property of the object. As a physical property patina is an expression of the passage of time, a visual marker of the object's timeboundedness reflected in signs of ageing and/or use. This thesis considers the implications of a digital patina, including its relevance for an analysis of the relationship between things and time or timeboundedness.  Lire la suite

Carbon dioxide and methane fluxes were measured between May 2003 and August 2004 on vegetated surfaces and pools of three peatlands located in the La Grande Riviere watershed, James Bay lowland, Quebec, Canada. Gas flux measurements were made using static chambers on a variety of sites in the three peatlands, chosen to represent the different biotypes present, from hummocks with water table position 35 cm below the surface to pools 100 cm deep. Average CH4 fluxes for the different biotypes on vegetated surfaces sampled during summer 2003 ranged from 3.5 to 197 mg m-2 d-1 while summer 2004 average floating …  Lire la suite

Abnormal connectivity between the prefrontal cortex (PFC) and other brain regions has been demonstrated in subjects with schizophrenia. We tested if abnormal connectivity, particularly between PFC and the medial temporal lobes (MTL), underlies the reduced brain activity and level of accuracy observed in schizophrenia subjects during episodic memory tests. We used fMRI to examine activation in fifteen chronic, medicated schizophrenia subjects and eighteen control subjects in two different recognition memory tests. The item recognition memory test required subjects to make old/new judgments, and the associative recognition memory test required them to make intact/rearranged judgments. We examined brain connectivity separately, with …  Lire la suite

This thesis is focused on addressing some of the limitations present in the spectral synthesis technique introduced by Zhang to render dynamic textures resembling falling snow. We improved the speed and the memory requirements of the rendering process by replacing the 3D inverse Fourier transform used in the rendering technique by a sequence of 2D inverse Fourier transforms. One of the issues with the rendering technique was that it didn't take into account the variations across the motion field that are visible when the observer undergoes non-lateral motion. In order to incorporate the motion field effects caused by egomotion (i.e. …  Lire la suite

The Automated Door Attendant, a multimodal interactive system functioning as a virtual secretary for a professor, is an example of an artificial agent deployed in a role typically assigned to humans. Accepting both speech and touch as input, it serves as an appointment scheduler, a document browser, a videoconferencing client, and a video answering-machine for visitors. This thesis provides an analysis of existing multimodal kiosk systems, describes the evolution of the current system's design, and presents the results of an empirical user study.  Lire la suite

Agrobiodiversity constitutes an essential resource for traditional rural populations. Home gardens are "hotspots" of agrobiodiversity and important loci of in situ conservation efforts. This study seeks to understand the factors affecting gardeners' choices and to assess the accessibility of planting material in rural communities of the Peruvian Amazon. Household surveys and garden inventories conducted in 15 villages of the Corrientes river (n = 300), and case studies in three of these villages (n = 89), allowed to describe the local and regional patterns of garden agrobiodiversity and the structure of planting material exchange networks. Analyses reveal a strong link between …  Lire la suite

Earthworms are well known for their casting and burrowing activities which improve soil structure and soil fertility. However, earthworm populations in temperate regions exhibit patchy distribution in space and time. This makes it difficult to predict how earthworm activities may influence paedogenesis and nutrient cycling processes at the ecosystem level. The main objective of this study was to determine the spatiotemporal dynamic of surface cast production of two earthworm species, Aporrectodea turgida and Lumbricus terrestris, on the row-interrow scale in a temperate soybean agroecosystem. Our observations demonstrated that casting activity was synchronous with plant growth. More casts were also found …  Lire la suite

In laudem sancti Michaelis (ILSM) is a heretical Old English homily on the Archangel Michael copied in the margins of an exemplar of Bede's Ecclesiastical History. The Introduction surveys the previous researches on ILSM. Chapter 1 analyzes it as a case of heterodoxy, discussing how it deformed the etymology of "Mi-cha-el?". Chapters 2 and 3 consider its Irish and Coptic analogues, then situate it in 11th-century England. Refining the insights of other scholars, I argue that a theme having to do with supernatural protection links ILSM to some of its companion marginalia, and that an archival intent motivated its preservation. …  Lire la suite

In Salmonella typhimurium, PhoP is the response regulator of the PhoP/PhoQ two-component regulatory system. Gel filtration chromatography showed that PhoP exists as a mixture of monomer and dimer regardless of its phosphorylation state. Unphosphorylated PhOPHis (a mutant harboring a histidine tag at the C-terminus) was mostly monomeric, whereas PhoP His~P existed as a mixture of monomer and dimer. Binding of PhoP to the PhoP box was barely influenced by phosphorylation as determined by surface plasmon resonance. In contrast, phosphorylation of PhoPHis induced a 200% increase in PhoPHis binding to target DNA. Fluorescence analysis revealed that the conformation of PhOPHis is …  Lire la suite

The Met receptor tyrosine kinase (RTK) and its ligand, the hepatocyte growth factor/scatter factor (HGF/SF), which regulate epithelial cell remodelling, dispersal and invasion, are deregulated in many human cancers. In the last twenty years, mechanisms of RTK activation and signalling have been studied extensively. In contrast, very little is known about the mechanisms of down-regulation of RTKs. At the time I began my thesis work, the family of Cbl ubiquitin-protein ligases emerged as negative regulators for RTKs. In this thesis, I demonstrate that c-Cbl is an important negative regulator of the Met receptor. Upon HGF stimulation, c-Cbl promotes ubiquitination of …  Lire la suite

The research for this dissertation focused on how children with Specific Language Impairment (SLI) use language in their interactions with peers. The study had three broad objectives: (1) to ascertain patterns of language use by the children with SLI in different contexts, (2) to evaluate the relationship of those patterns to difficulties in peer interaction reported in the literature, and (3) to explore the ramifications of groups composed uniquely of children with SLI for peer talk and peer interaction. The participants were several children (mean age 4 years, 10 months) enrolled in a preschool language program designed specifically for children …  Lire la suite

Unmanned Aerial Vehicles ("UAV") have been a part of aviation from the infancy of manned aviation; yet, have not reached their fullest potential as they are not integrated into the national airspace system ("NAS"). However, we are at the edge of technological breakthroughs to make integration a reality. Nevertheless, the regulatory construct necessary to provide safe integration of UAVs is unfinished. This thesis looks at necessary regulatory changes within the United States to allow for integration of the UAV into the NAS. I will first define the UAV and look at its historical roots. Then, I will review existing regulations …  Lire la suite

The research for this doctoral dissertation was undertaken to: (1)establish a rationale that is supported by published laboratory and clinical data for prospective clinical investigation of the therapeutic maintenance of the M184V mutation in human immunodeficiency virus type-1 (HIV-1) reverse transcriptase (RT) in antiretroviral therapy-experienced patients with virological failure, and, (2)to study the relative effectiveness of various nucleoside analogue reverse transcriptase inhibitors (NRTIs) that are structurally-unrelated to 3TC in selecting and/or maintaining M184V in tissue culture and whether continuous exposure to therapeutic levels of 3TC is the only means of attaining this objective. Accordingly, we have evaluated the ability of …  Lire la suite

This thesis is as an attempt to overview the forms of trade secret protection presently in place in the United States, Canada, the European Union and Romania. These jurisdictions were selected because they present a diversity of legal background and a variety of forms of trade secret protection. The introductory chapter deals with the historical and economic backgrounds of the trade secret protection. An overview of trade secret protection at international scale is also provided. The thesis compares the forms of trade secret protection available in each jurisdiction. Based on the survey, the thesis comes to an answer of the …  Lire la suite

Inherited disorders of calcium homeostasis, familial hypercalcemia (FHH) and neonatal severe hyperparathyroidism (NSHPT) are caused by inactivating mutations, and autosomal dominant hypocalcemia (ADH) is caused by activating mutations in the calcium-sensing receptor (CASR). This receptor belongs to group C of the G-protein-coupled receptor (GPCR) superfamily, one of the largest groups of cell-surface receptors. The CASR is expressed abundantly in the parathyroid gland and in the cells lining the kidney tubule and senses small changes in circulating calcium concentration and once activated it inhibits parathyroid hormone (PTH) secretion and renal tubule calcium reabsorption. The CASR undergoes core (immature) N-linked glycosylation in …  Lire la suite

This thesis offers new perspectives on the Yiddish poet and novelist Chaim Grade, examining his reflections on the world of historic Lithuanian Jewry from the outset of his career through his post-Holocaust novels. Chapter one explores the gap between the historical reality of interwar Vilna and its literary representation in his novel Di agune and questions the widely accepted view of this work as a credible historical source. Chapter two deals with Grade's depiction of his experience as a student in a Novaredok Musar yeshiva, contrasting the depiction of this yeshiva in the poem Musernikes (1938) and the novel Tsemakh …  Lire la suite

This work proposes a double analysis of the mundane society representations between 1885 and 1914, in the press and the novel. This analysis separates these two categories of media to insist on their particularities, and tries to think of them in terms of an interaction. A first part explores the organisation of the topics and the main genre of the mundane society in the press, applying the social discourse theory. The analysis is based on the perusal of a set of representative daily newspapers (Le Gaulois, Le Figaro) and of weekly and monthly publications (Le Grand monde, La Vie parisienne, …  Lire la suite

Persistent peripheral inflammation is thought to induce functional plasticity of spinal dorsal horn neurons, and may produce changes in glutamate receptor expression. Alterations in expression and cellular localization of group I metabotropic glutamate receptors (mGluR1alpha and mGIuR5) is important in various neuronal systems, and these receptors are also known to modulate nociceptive neurotransmission in the spinal dorsal horn. The aim of the present study is to determine whether persistent inflammation produces alterations in ultrastructural localization of mGluR1alpha and mGluR5 in the dorsal horn of the spinal cord. Persistent inflammation was induced in rats by an intraplantar hindpaw injection of complete …  Lire la suite

Tethers have been used in space for quite some time. However, the concept of a multi-tethered system has received less attention. This thesis investigates the dynamics of certain configurations of multi-tethered satellite formations in Low Earth Orbits. Certain simplifications have been made prior to the investigation of the problem; these include considering the satellites to be point-masses and the tethers to be massless and straight. Configurations termed hub-and-spoke and closed-hub-and-spoke are analyzed. The local motion is studied under two distinct specifications for the orbital motion of the system: first, prescribed motion of the system centre of mass and second, prescribed …  Lire la suite

In the present analysis, the constant alphas of Quantum Chromodynamics (QCD) is determined from dijets production in the regime of neutral current deep inelastic scattering (NC DIS) with high momentum transfer Q2. This measurement uses the data collected between the years 1998 to 2000 by the ZEUS detector located on the HERA ring collider in Hamburg, Germany. Corresponding to an integrated luminosity of 82.7 pb-1, the data were produced by the interactions between 27.5 GeV electrons (or positrons) and 920 GeV protons. Defined in a phase space reducing the theoretical and systematic uncertainties, the dijet production is observed as well …  Lire la suite

The present work consists of three parts. First, I demonstrate the effectiveness of C12E5/hexanol as an orienting media for the measurement of residual dipolar couplings (RDCs) at low pH and for proteins with the positively charged surfaces, such as carbon storage regulator A at pH 4.5 and catalytic fragment of 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP-CF; theoretical pI 8.99). Second, the structure of the regeneration-induced CNPase homolog was determined based on 15N-1 H, 13C'-13C alpha, and 13Calpha- 1Halpha RDCs measured in Pf1 phage alignment media. Finally, 2D experiments based on the recently introduced SAD-REDOR technique for the measurement of RDCs in …  Lire la suite

The worldwide rates of asthma have been increasing in the past twenty years, coinciding with a decreasing prevalence of tuberculosis in the major asthma endemic regions. The hygiene hypothesis proposes that in countries with better hygiene, reduced exposure to pathogens is responsible for the rising prevalence of allergic diseases. Mycobacterium tuberculosis , the cause of tuberculosis (TB), is thought to be a critical effector of the hygiene hypothesis since it can skew the immune system away from developing into an atopy associated immune profile. Hence, absence of exposure to M. tuberculosis might remove suppression of asthma development. Based on the …  Lire la suite

Over the past forty years, polls have clearly indicated a decrease in expressions of racism and sexism. However, while people appear more tolerant, many social scientists claim that prejudice is still prevalent, although in a more disguised form. Indeed, it may be difficult to distinguish a person who is genuinely nonprejudiced from someone simply conforming to external nonprejudiced norms. This thesis presents three experiments that focus on amen and women in the workplace in order to investigate the extent to which the dilemma of genuine nonsexism exists. Experiment I investigated men's hiring preferences. Men whose nonsexist self-conceptions were threatened with …  Lire la suite

The perceived availability of social support has been documented as a protective mechanism among adults and adolescents but little work has been done with children with emotional and behavioral difficulties (EBD). The current research addressed this gap in literature with a sample of teacher-nominated children with EBD. Fifty-four children (43 males, 11 females), 56 parents, and 27 teachers completed questionnaires on perceived social support and behavioral, emotional, and social functioning. Results suggest a pattern of domain specific social support relating to domain specific adjustment outcomes. Furthermore, the importance of child ratings over parent and teacher ratings of social support was …  Lire la suite

A standard element of many news stories that mention Islam is the 'expert.' An expert contributes what is presented as objective knowledge about Islam to a news story. Through ostensibly objective statements, an expert plays a significant role in the representation of Islam. In this thesis I theorize the concept of an 'expert on Islam' in news media and I confirm my theoretical positions through a content analysis of two Canadian newspapers' use of the expert on Islam; these two newspapers are The Globe and Mail and The National Post. The thesis develops two arguments based on the results of …  Lire la suite

In order to increase vehicle fuel efficiency while improving safety and performance and maintaining affordability, the global steel industry has initiated the use of advanced high strength steels that ultimately result in the design of stronger, lighter and more energy efficient vehicles. Tubular steel columns are extensively used in the automotive body structure due to their inherent capacity to absorb energy on impact. Hence, the objective of this research work is to study the crashworthiness performance of columns made from advanced high strength steels. To conduct this study, computational simulations are developed to accurately assess the influence exerted in the …  Lire la suite

This research followed acetate carbon (C) uptake, metabolism, and fate through a typical modern Kraft pulp and paper mill AS system. Freshly collected mill biomass (AS floc suspensions) was placed under conditions representing four key phases of AS biotreatment: (1) initial acetate uptake by aerated starved AS; (2) ongoing acetate uptake; (3) aerobic metabolism of acetate-loaded AS in acetate-stripped effluent; and (4) anaerobic, settled biomass metabolism. Conditions mimicked the mill system as closely as possible. Acetate carbon uptake kinetics and conversion to CO2, growth products, PHB, and secreted metabolites in each of the four phases were measured. The role of …  Lire la suite

During the 1970s, Gianni Celati uses his novels as a workshop for his investigation into language, literature and communication. Le avventure di Guizzardi, La banda dei sospiri and Lunario del paradiso are crucial works in which Celati develops a style based on oral language as a way of bringing life closer to art and escaping the self-referentiality of the literary vanguard. Celati also experiments with a poetics of "ordinariness," both in style and content, as a means of broadening his audience and the reach of his social commentary. An examination of Celati's novels of this period reveal an intellectual that …  Lire la suite

The opioid receptor family is comprised of three members: mu, delta and kappa, all of which are G protein coupled receptors, primarily acting through Galphai/o subunits. Clinically, mu opioid receptor (MOR) agonists are used in the treatment of moderate to severe pain. delta opioid receptor (DOR) agonists are being developed as alternative analgesics, since stimulation of this receptor results in fewer adverse side effects. Characterization of behaviourally relevant mu and delta opioid receptors, as well as interactions between them, will provide a better understanding of opioid agonist-induced analgesia. Although the behavioural knockdown after antisense targeting of MOR has been well …  Lire la suite

Neurons transform analogue input into digital representations (i.e. spike trains) that can be communicated to other neurons. In the process of incorporating information from different sources, representations are modified. These modifications constitute computations. This is particularly relevant in the pain system where, according to the gate control theory, sensory input from multiple modalities as well as cognitive information influence the relationship between noxious input and pain perception. Much of this control is exerted in the spinal dorsal horn, including lamina I, but the biophysical basis for those computations remains unknown. This thesis aims to elucidate basic computational processes involved in …  Lire la suite

The High Risk Assessment Review Team (HART) in Belleville, Ontario is a community coordinated initiative that reviews domestic violence cases before the criminal court. Record analysis was conducted on 60 case files that had gone through criminal court in that jurisdiction. The purpose was to determine if a sample of cases reviewed by HART (n=30) would yield a higher rate of conviction and increased contact with community agencies when compared to a sample of cases (n=30) prior to this team being implemented. A logistical regression yielded no statistically significant results but did demonstrate a higher rate and likelihood of conviction …  Lire la suite

This thesis presents low-rate personal area network coordinator design and implementation on both hardware and software fronts. It portrays integration techniques used to enhance the existing wireless sensor network infrastructure previously developed by the Microelectronics research group. The infrastructure was made for data collection and sharing during educational conferences and alike gatherings. The system is designed to be flexible and rapidly reprogrammable, while keeping low-power and low-cost as the primary design objectives. Augmenting the hardware is the wireless network protocol specifically conceived for low-power and low-rate applications - IEEE 802.15.4. Both application and implementation aspects were covered in order to …  Lire la suite

Himesis is a complete yet minimal kernel for meta-modelling and model transformation, which consists of a specification of hierarchical graphs and in a highly efficient matching algorithm. Himesis graphs encode the essence of models: nodes, edges, containment, attributes, names and labels. There is a defined set of events which transform the graphs. Above all Himesis introduces an explicit notion of hierarchy, which allows the specification of formalisms which were very hard to meta-model in the past, such as graph grammars. Moreover, with containment, it is possible to couple and reuse existing formalisms. Himesis implements HVF, a new matching algorithm based …  Lire la suite

The pituitary gland is a very convenient model to study mechanisms implicated in cellular differentiation. This endocrine gland is composed of six cell lineages, each committed to the production of a different hormone: thyrotrophs (TSH), somatotrophs (GH), lactotrophs (PRL), gonadotrops (LH, FSH), melanotrophs (alpha-MSH) and corticotrophs (ACTH). ACTH and alpha-MSH are both processed from the same precursor, proopiomelanocortin (POMC). Pituitary hormone-producing cells differentiate sequentially from a common epithelial primordium, Rathke's pouch, under the combinatorial action of a subset of tissue- and cell-restricted transcription factors. In corticotrophs, Tpit and NeuroD1 are important for POMC transcription. Their expression closely precedes that of …  Lire la suite

Electron microscopy (EM) is an important tool in organellar proteomics, where it is used to validate sample purity and to confirm protein presence. Current sample preparation techniques are manual, labor-intensive and time-consuming. To overcome these problems, an electron microscopy proteomic organellar preparation (EMPOP) robot is being developed for parallel preparation of up to 96 subcellular fraction samples in an efficient, repeatable and standardized manner. This thesis describes the development and validation of the software that controls the EMPOP robot. The software was organized in two coordinated levels consisting of a: (1) human-machine interface (HMI), and (2) low-level real-time control routines. …  Lire la suite

The "encyclopedic imagination" describes an artist's conviction that a work of art must be expansive and inclusive to a point of total embodiment. The artist (or dramatized artist figure) implies that the work of art must give a total account not only of the subjective life of the artist but of the reality to which the representing self responds. The focus of this study is not on any work's encyclopedic achievement (for the artist's inclusive ideal always remains well outside the actual capacity of the work), but on the relationship of the ideal of aesthetic all-inclusiveness to a problematic ideal …  Lire la suite

How are Centre parties distinct from Left and Right parties in term of their policy preferences? The scholarship on political parties either ignores Centre parties or treats them as a residual category. In this study, I attempt to rescue Centre parties from obscurity by looking at a quintessential Centre party: the Chilean Christian Democratic Party (PDC). Between 1990--2000, the PDC led two centre-left Concertacion coalition governments under Patricio Aylwin (1990--1994) and Eduardo Frei (1994--2000). It was the PDC's responsibility to negotiate the 'Chilean paradox': a country that had achieved economic success with neoliberalism and become a "model" for Latin America …  Lire la suite

Montreal is the second largest metropolitan centre in Canada. It is exposed to significant seismic hazards and ranks second in urban seismic risk in Canada. The seismicity of Eastern Canada is controlled by intraplate earthquakes. The damages caused by the earthquakes on infrastructures depend on the quake magnitude, distance from the epicentre and the type of underlying soil deposit. The surficial deposits and landscape of Montreal have been shaped by many geological episodes. Alternate periods of glaciation and melting, deposited considerable quantities of soft soil, and were later altered by the emergence of the Champlain Sea, depositing clay and sand …  Lire la suite

Java programs are deployed in a bytecode format that is executed by a Java virtual machine (JVM). JVM performance is determined by several major components: execution engine, garbage collector, and threading system. The static compilation and optimization approach, such as taken in C/C++ compilers, does not fit in Java's execution model very well because Java allows dynamic class loading, lazy resolution, just-in-time (JIT) compilation, and garbage collection. These dynamic features presents new challenges to JVM designers. In this thesis, we study both the challenges and opportunities of dynamic optimizations in Java virtual machines. Our contributions include a new garbage collector …  Lire la suite

The Province of Quebec launched a province-wide reform of its schools and adult education centres in 1997 to respond to the exigencies of an increasingly multicultural population, and the requirements of a knowledge-based society. The reform aims to enhance democracy and citizenship. Based on the recent explosion in philosophical literature about varying models of democracy, and the concept of self advanced by each model, it is important to investigate what vision of democracy and concept of self is proposed for Quebec through this reform and what institutional measures are being adopted by the educational community to ensure its realization. This …  Lire la suite

This doctoral dissertation, as part of a large and ongoing CIHR-funded study, used a subset of the total sample to evaluate the contribution of interactive health communication (IHC) as a complement to more traditional means of informational support (Care-as-usual) to optimal adjustment of women newly diagnosed with breast cancer (N = 135). According to the study protocol, participants in the experimental group received an IHC educational intervention for an eight-week period. Measures of psychosocial adjustment and information-related variables were administered in interviews at Time 1 (pre-intervention) within 8 weeks of initial diagnosis, and again 8 weeks post-intervention (Time 2). Psychosocial …  Lire la suite

Vali, Hojatollah (Supervisor)  Lire la suite

This dissertation develops a meaning oriented model of the relationship between culture and the subjective experience of psychosis, by analyzing interviews and other ethnographic data collected over the course of a 12 month fieldwork in Istanbul, Turkey. The theoretic framework for the study is introduced on the basis of detailed discussions of the notion of schizophrenia, the questions of Turkey and Turkish identity, and the basic theories of semiotics. Derived from the theoretic framework, four principles are then proposed as fundamental features of the relationship between culture, meaning systems, subjectivity and psychosis, as follows. (1) the inseparability of the notions …  Lire la suite

The current international tax regime was conceived at the beginning of the 20th Century and the rules have remained relatively unchanged since then. The operational rules of the international tax regime were designed for an economic era in which major international commercial enterprises were confined within a physical paradigm, and they had succeeded in achieving an acceptable and practical allocation of tax revenue that was being generated from international commerce. As commerce sunders itself from its physical boundaries, the traditional international tax rules that are confined within a physical paradigm fail to provide an adequate solution to the tax issues …  Lire la suite

This study identifies several points of convergence between specialty cafe chain labourers and the organizations that employ them. Cafe chains are premised upon their consistent reproduction of experience in numerous locations, so organizations must put multiple systems of control into place to ensure their homogeneity across the chain. Foremost among these are Fordism and Taylorism, two systems that emphasize rational and efficient routines made up of highly segmented and de-skilled tasks, so that each step in the productive process is done the "one best way." Because employees' friendly service is part of the experience that cafes attempt to reproduce across …  Lire la suite

Resin transfer molding (RTM) has great potential to become an efficient and economical process for fabricating large and complicated automotive composite structures. Low capital investment, excellent mechanical properties, closed mold processing, low pressure equipment, short cycle times and process versatility in component integration and assembly, make RTM very attractive for high volume automotive applications. However, a high class surface finish, required for exterior car body panels, is difficult to achieve with RTM. There are several material and process parameters that severely affect the surface quality of RTM molded components. One of the major contributing factors is the shrinkage related to …  Lire la suite

The aim of this work was to investigate the role of CD4 + T cells, central to airway inflammation in asthma, in airway remodeling. Structural changes that occur in asthmatic airways in association with inflammation include an increase in airway smooth muscle mass, which participates in causing airway hyperresponsiveness. We aimed to gain further insights into the mechanisms that may link inflammation with remodeling using a rat model of experimental asthma. We hypothesized that CD4+ T cells drive airway smooth muscle remodeling. Adoptive transfer of CD4+ T cells from ovalbumin-sensitized rats induced increased proliferation and inhibition of apoptosis of airway …  Lire la suite

The aortic valve is a complex and dynamic structure, which, with age, degenerative disease, or genetic abnormality, can become pathological and cease to function as in its natural state. A particularly prevailing disease of the aortic valve occurs when the valve becomes abnormally dilated, and regurgitation, or backflow of blood occurs. When this condition becomes severe and is accompanied by debilitating clinical manifestations, the standard procedure has been to replace the entire aortic root and valve with a composite valve graft incorporating either a mechanical or a bioprosthetic valve, during a type of surgery known as the Bentall procedure. However, …  Lire la suite

Similar to passive exposure to cigarette smoke, building occupants, in homes and in offices, are passively exposed to volatile organic compounds that are being emitted form surfaces of interior finishes and furnishings. Identifying emissions from surfaces of interior finishes and furnishings requires in-situ sampling. Interior finishes and furnishings used in homes and offices are many and varied. Current available methods used for sampling surface emissions from interior finishes and furnishings require the use of environmental chambers in laboratory settings. The in-situ applications of these lab-based chambers are limited. A novel method for in-situ surface emission sampling is needed. This thesis …  Lire la suite