McGill University Thèses et mémoires publiés en 2004

A software system that automatically classifies MIDI files into hierarchically organized taxonomies of musical genres is presented. This extensible software includes an easy to use and flexible GUI. An extensive library of high-level musical features is compiled, including many original features. A novel hybrid classification system is used that makes use of hierarchical, flat and round robin classification. Both k-nearest neighbour and neural network-based classifiers are used, and feature selection and weighting are performed using genetic algorithms. A thorough review of previous research in automatic genre classification is presented, along with an overview of automatic feature selection and classification techniques. …  Lire la suite

This thesis presents the results of a search for the decay B 0 → J/Ψγ at the BABAR experiment. This is expected to be a very rare decay, with a branching fraction of the order of 10 -8, too low to be measured at BABAR; so the aim is instead to determine a 90% CL upper limit for beta(B 0 → J/Ψγ). No prior limit has been set in this channel. The analysis uses the complete data set from Runs 1, 2, and 3, comprising a total integrated onpeak (offpeak) luminosity of 113.1 (12.0) fb-1; and both SP4 and SP5 …  Lire la suite

While sanctions proliferated after the Cold War, concerns remain about their effectiveness and humanitarian impact. In addressing these concerns, scholars have offered diverse frameworks generally emphasizing sanctions' design or application. This thesis argues that the proper focus of concern is conceptually prior to each of these. In fact, lacking political will has been characteristic of sanctions cases and the root of sanctions' failures. Significantly, the cost-benefit calculus informing policymakers' political will has been systematically incomplete. Sanctions are often judged on their lifting, in the country on which they were imposed, yet this unreasonably crops out broader sanctions' impact. Sanctions have …  Lire la suite

Une coloration totale d’un graphe est le coloration des arêtes et des sommets telle que deux sommets adjacents ont des couleurs différentes, deux arêtes incidentes ont des couleurs différentes, et une arête a une couleur différente de celles des ses extrémités. Si nous formulons le problème de trouver le nombre chromatique total comme un programme linéaire entier, nous pouvons considérer la relaxation connue comme la coloration totale fractionnaire. Dans cette thèse nous présentons un algorithme pour calculer le nombre chromatique total d’un graphe en temps polynomial en moyenne. Nous présentons aussi un algorithme qui calcule asymptotiquement presque sûrement le nombre …  Lire la suite

Cardiac action potential (AP) properties are not uniform because of functional specialization in different regions. The thesis of these studies was that important aspects of regional cardiac electrical function in health and disease are determined by heterogeneous ionic current expression. The inward rectifier current, IK1, responsible for the resting membrane potential (RMP) and late repolarization, is greater in ventricle than atrium. Atrial-ventricular IKI differences result in important electrophysiological differences between atrium and ventricle. To gain insight into the mechanisms of this IK1 variation, we compared the expression and distribution of inward rectifier subunits Kir2.1/2.3, believed to underlie IK1, in both …  Lire la suite

Generation X has often been defined as being without role models or inspiration. Nevertheless, it is possible to detect a sizeable amount of intertextual references in several Quebecer books written by authors of that generation. In Quebec, these young writer's influences are as distinct as they are diverse, varying from Kerouac to Hemingway and from Sartre to Camus. But concerning their Quebecer role model, one name continually returns, that of Rejean Ducharme. The goal of this thesis is to illustrate the presence of ducharmesque universe in three Generation X novels, namely Le souffle de l'harmattan by Sylvain Trudel, Vamp by …  Lire la suite

The purpose of the present work was to remove selectively manganese from a neutral leach zinc-rich solution at 80ºC using the gas mixture of sulphur dioxide (SO2) and oxygen (O2) as oxidizing agent. In order to determine the optimum conditions for manganese removal using SO 2/O2, several semi-batch experiments were performed, where the effects of pH, ORP, SO2/O2 ratio, mixing intensity, etc. were investigated. Results of these tests showed that SO2/O 2 was a fast and effective oxidant for removing manganese down to ppm level provided that the appropriate reactor design, agitation and SO 2/O2 ratio were employed. In an …  Lire la suite

Timely and accurate assessment of unilateral spatial neglect (USN) post stroke is a critical component of best practice, given that a recent Clinical Practice Guidelines for stroke has recommended the standardized assessment of USN within 48 hours of regaining consciousness following a stroke. This multi-centered, retrospective study using data from medical charts of a representative sample of individuals admitted to 10 Ontario acute care hospitals from July 15th to December 15th 2002, examined the prevalence, timing and frequency of use of standardized assessments to evaluate USN post stroke. Out of the 248 subjects who should have received a USN assessment, …  Lire la suite

This thesis provides an analysis of the portrayal and function of relationships between women in the following Erzahlungen by Ingeborg Bachmann: "Ein Schritt nach Gomorrha," "Das Gebell," and "Drei Wege zum See." The major research questions include whether there is a similar representation of female-female interactions and a common conception of gender and identity construction arising from these interactions. In addition to offering a unique perspective on relationships between women, this analysis presents "Das Gebell" as the story of two women, rather than one that focuses on the relationship between a mother and her son, which has predominately been the …  Lire la suite

Research on tutoring has shown that the student's interaction with the tutor determines the learning outcomes. In human tutoring, the responsibility of the interaction is shared between the tutor and the student. In the case of a computer coach such as the McGill Statistics Tutor, the control of the interaction is put entirely in the hands of the learners. Learners' ability to interact with the system productively therefore represents a critical aspect affecting the learning outcomes. This ability of help seeking (Nelson-LeGall, 1981) has not been well researched from a cognitive science point of view in the context of computer-supported …  Lire la suite

Three-dimensional (3D) ultrasound is an emerging new technology with numerous clinical applications like measuring the volume of the prostate, monitoring fetal development, or evaluating brain shift during neurosurgery. Ultrasound probe calibration is an obligatory step in order to build 3D volumes from 2D images acquired in a freehand ultrasound system. The role of calibration is to find the transformation that relates the image plane to a sensor attached on the probe. This thesis is a comprehensive review of what has been published in the field of ultrasound probe calibration for 3D ultrasound. The thesis covers the topics of tracking technologies, …  Lire la suite

Thin multilayer films were prepared through layer-by-layer adsorption of oppositely charged polyelectrolytes in aqueous media using a recently established electrostatic self-assembly approach. The adsorbing polyelectrolytes can be classified as either weak or strong based on their level of dissociation in solution. The density of charge in weakly charged polyelectrolytes, unlike in strongly charged ones, can be controlled by adjusting the solution pH about the value of its dissociation constant. At the onset of this dissertation, there were some fundamental and unresolved questions regarding assembly mechanisms, kinetics, and internal structures of the layers in polyelectrolyte multilayer films (PEMs). The studies here …  Lire la suite

The purpose of this study was to explore aboriginal perspectives of diabetes, nutrition and health so as to eventually develop culturally-appropriate means of implementing diabetes prevention and intervention activities. The participants included community members living in an Eastern James Bay Cree community in northern Quebec. In this qualitative research study, in-depth interviews, focus groups, and participant observation were used for data collection. Key themes that emerged from analyzing the in-depth interviews were "re-presented" using "found poetry" so as to capture the participants' experiences and perspectives using their own words. Focus groups were carried out to share the initial findings from …  Lire la suite

A delivery method for the oral administration of thalidomide for lowering tumor necrosis factor alpha (TNT-alpha), and thus Crohn's disease-related inflammation in the proximal small intestine, using two separate engineered polymer microcapsules is explored in this thesis. Membrane formation of both alginate-polylysine-alginate (APA) and alginate-chitosan (AC) capsules are discussed and thalidomide encapsulation procedures have been described. In-vitro tests have been used to monitor capsule degradation and drug release in a simulated gastrointestinal environment. Also, culture and use of RAW 264.7 mouse macrophage cells for the simulation of the human intestine is described. Results show two separate methods of drug delivery …  Lire la suite

Fading Points is a piece of music for large wind ensemble. The work is concerned with time perception and is designed to convey to the listener a long temporal progression from slow music to fast music. To this end, the work is written using musical gestures specifically designed for their portrayal of musical time. The work consists of four sections, each of which is described in detail in the analytical part of the thesis. The analysis also describes the rhythmic language, which is created around short rhythmic cells. These cells are based on ratios and are used in all levels …  Lire la suite

Background. Evidence-based practice aims to improve patient care and service delivery, particularly in the management of individuals with low back pain, the largest client group seen by out-patient physiotherapists. Objective: This study determined the prevalence of use of interventions with evidence of effectiveness in the management of acute non-specific low back pain by physiotherapists. Methods. A multi-centered cross-sectional study was conducted on 100 physiotherapists working with low back pain patients. Using a telephone-administered interview, therapists described their current and desired treatment practices for a typical case of low back pain. Each intervention reported was coded according to its evidence of …  Lire la suite

Damage from large hail is a costly problem in Canada and other parts of the world. With continuous increase in computer power, numerical weather prediction (NWP) models are getting closer to resolving the convective scale, where it is appropriate to employ explicit microphysics schemes. This dissertation examines the potential to predict hail using an explicit microphysics scheme in an NWP model. To this end, the requirements of a bulk scheme to model the hydrometeor size distribution are investigated. A number of schemes in the literature use the double-moment method with a three-parameter gamma distribution function to represent the size spectrum. …  Lire la suite

The regulation of the genome by the epigenetic modifications of DNA methylation and histone modification is increasingly recognized as a vital factor in the development, physiology and pathology of vertebrates. There is mounting evidence suggesting that both aberrant DNA methylation and histone modifications are common events in cancer. This has lead to the establishment of both DNMTs and HDACs as important targets in cancer therapy. There are currently several clinical trials that are testing inhibitors of both DNMTs and HDACs as anticancer agents. This thesis attempts to understand the roles that DNMT1 and HDAC1 play in the regulation of gene …  Lire la suite

At a government hospital in the town of Dajabon, in the northwestern Dominican Republic, doctors and nurses must make decisions on whether or not to treat Haitian patients who have crossed the border in search of health care. This thesis examines the discourses and practices of Haitian patients and Dominican health care providers in the context of two co-existing but contrasting rhetorics: health as a human right, and medical humanitarianism. Using data collected through semi-structured interviews and participant observation, I examine how social, political, and economic forces shape medical encounters on the Haitian-Dominican border.  Lire la suite

The early Tertiary marked a period of intense magmatic activity in the Canadian Cordillera as a consequence of tectonic restructuring within the Kula-North American plate system from orthogonal to oblique convergence. Resultant calc-alkaline volcanism formed a discontinuous belt (Challis Arc) along the eastern margin of the Coast Plutonic Complex (CPC) from south-eastern Alaska through Yukon into west-central British Columbia and northern Washington State. The Sifton Range volcanic complex (SRVC) is the Yukon's largest Paleogene erosional remnant of volcanic rocks (240 km2), and represents the only coeval volcanic-plutonic suite within the Sloko-Skukum Group of southern Yukon Territory and northern British Columbia. …  Lire la suite

This dissertation interprets the poems of the book of Lamentations through the study of their imagery and of the themes expressed through that imagery. The introduction places the study in the context of literary studies of biblical texts and of recent scholarship on Lamentations. The book is read in its canonical order, identifying the images and patterns of imagery which occur in each poem. Major images are compared with similar images in other biblical poetry and interpreted as to the themes which they express. Comparison of imagery which appears in several poems illustrates how the experience of the fall of …  Lire la suite

Signaling molecules play essential roles in communication between cells. Wnt signaling molecules are critical for embryonic development of several organisms. I examined the involvement of Wnt signaling during two major developmental processes, namely embryo implantation and formation of the embryonic body axes. Using RT-PCR analysis, I showed that multiple Wnt genes are expressed in the blastocyst at the time of implantation. Moreover, expression of Wnt 11 requires both estrogen produced by the mother and the uterine environment. Using a transgenic approach, I showed that beta-catenin-regulated transcriptional activity, which is a major transducer of Wnt signaling, is activated in the uterus …  Lire la suite

Countries in the developing world, in attempts to promote investment in land and agricultural productivity, and to establish frameworks for economic development, have regularly embarked on extensive tenure reforms designed to replace customary forms of tenure with private individual forms. In the Kenya rangelands, the Group Ranch system: a hybrid tenure system that allows communal ownership and use of titled land, was created and implemented in the rangelands where private tenure was thought to be unsuitable. This thesis discusses the failure of the Group Ranch system in Kajiado District, and the parallel transformation of Maasai communal lands into private, individual …  Lire la suite

Is it an activity qualified as torture only when it is carried out for certain purposes? At the heart of the debate lies the question of whether or not corporal punishment is a form of torture. Aspects of corporal punishment remain acceptable according certain religious traditions. An example of this is found in traditional Islamic law, which has banned both torture and other cruel, inhuman and degrading treatment or punishment, when used for the express purpose of obtaining confessions or information. In other circumstances, however, severe corporal punishment is acceptable in Islamic law. As a result, some Islamic states whose …  Lire la suite

A microstructural and morphological analysis of polymer/layered silicate nanocomposites (PLSN) is proposed. The analysis employs wide angle x-ray diffraction (WAXD) and to a larger extent, transmission electron microscopy (TEM). Polyamide-6 (PA) and polystyrene (PS) nanocomposites were produced by melt processing the resins with several grades of organically modified clay in a twin screw extruder (TSE). The TSE was operated in two different configurations (C and A). The effects of the type of organoclay, TSE configuration, clay concentrations and addition of a compatibilizing agent in the matrix were evaluated. Both WAXD and TEM analysis revealed exfoliated or intercalated structures for PA-based …  Lire la suite

This qualitative inquiry into Critical Friends Groups (CFGs) at Lower Canada College (LCC), a coeducational, bilingual, K-12, private, day school in suburban Montreal, focusses on the impact of CFGs on teachers' professional growth and classroom practices. Using interviews, focus groups, participant observations and a questionnaire, I examined the recursive cycle of professional growth and transformation, and rooted the inquiry within the theoretical frameworks of reflective practice, the dialogic imagination, social constructivist learning and critical theory. I conceptualize teachers' professional growth as the transformation of professional practices through the deepening knowledge and expertise that arises out of collaborative inquiry and collegial …  Lire la suite

Conservation of the world's biodiversity is increasingly viewed as a development problem, requiring the alleviation of poverty together with the promotion of alternative livelihoods in resource-reliant communities. To be successful, such efforts must recognize the underlying logic of resource-users' livelihood choices. This study uses the activity of aquarium fish extraction in the Peruvian Amazon as a case study through which to examine the role that physical and non-physical assets (primarily knowledge) might play in determining households' participation patterns. An initial survey of the regional trade, undertaken through interviews with trade participants (n = 38) and analysis of government documents, revealed …  Lire la suite

Since the end of World War II, the shopping center has been diffused as a building type through the western world and has acquired a central role in suburban territories. It is perceived as a "standardized" building and as the product of the process of economic globalization. Most of the time, the shopping center is conceived on the basis of regional considerations, and so it presents difficult connections with the surrounding urban tissues. Even if it contributes in an important manner to the life of suburbia, it is an introverted building that has limited relationships with exterior spaces. The thesis, …  Lire la suite

Child protection work largely relies on mothers in fulfilling its aim to protect children and support families. Mothers are expected to shield children from abuse and neglect regardless of circumstance. Fathers evade such expectations, and are rather treated as unimportant or as aggressors. In either case, they are distanced from the child protection process. These divergent expectations of mothers and fathers often go unnoticed in child protection practice, as social workers are consumed with the urgent need of assessing risk to children. Workers' reliance on mothers becomes a habit that is not easily countered because there is neither the time …  Lire la suite

The purpose of this dissertation is to investigate the influence of a component of the service environment, namely music, on consumers' judgments and behaviors. More specifically, we were interested in the underlying mechanisms of pleasure effects. We proposed, based on theories from psychological environment and scene perception, that the pleasure induced by background music first influences the overall attractiveness of the service atmosphere, which in turn, has the ability to influence the attractiveness of the persons found in this environment, specifically the service personnel. Finally, these two dimensions of the service environment (i.e., the atmosphere and the personnel) are antecedents …  Lire la suite

Recent genetic studies indicate an association between Attention Deficit Hyperactivity Disorder (ADHD) and the dopamine transporter gene (DAT1) with possible preferential relation to hyperactivity and impulsivity behaviours. The present study investigated attention-related behaviours in a non-clinical sample to determine whether the modulation of these behaviours is associated with genetic variability of the DAT1 within the normal population. A secondary question explored whether gender was associated with the measured attention-related behaviours. Twenty-six children were observed in the classroom during performance of independent academic work. Motor behaviours during task performance were scored using the Restricted Academic Situation Scale. Major behavioural problems were …  Lire la suite

In this era of modern medicine, impaired wound healing is still a major medical problem with limited treatment options, especially for the elderly and for diabetic patients. One of the molecules that are recognized to be critical in wound healing is transforming growth factor (TGF-beta). Exogenous direct application of TGF-beta to the wound promotes healing in animal models. Since this property of TGF-beta is cell context-dependent, the present study investigated the role of ischemia/reperfusion using a pig-skin flap model (in vivo). In addition, we studied the effects of: (i) hypoxia/reperfusion, (ii) steroids, and (iii) the combined effect of both hypoxia …  Lire la suite

The world around us contains a variety of visual information, both first-order (luminance-defined) and second-order (defined by characteristics other than luminance). Previous studies suggest that the human visual cortex employs distinct mechanisms for segregating regions whose borders are defined by modulations of first- and second-order properties. This study uses a new approach of human psychophysics and fMRI experiments to explore the brain responses to both first-order and second-order (orientation, spatial frequency and contrast) texture borders. The results reveal differential activation among these modulations both in known retinotopic areas and in higher occipital/parietal regions. Orientation modulated textures elicit significantly different responses …  Lire la suite

The current study examines several recent comparisons made between the writings of Nagarjuna and Derrida. The main question under examination is why in particular should such a comparison of two widely different thinkers hold obvious appeal for contemporary scholars? In an attempt to answer this question the comparisons of Robert Magliola, David Loy, Harold Coward and others are analysed as are critiques of this type of comparison presented by Richard Hayes, A. Bharati and others. It is concluded that the basis for these comparisons is a strong concern for a "middle way" perspective between forms of absolutism and nihilism in …  Lire la suite

This study focuses on the implementation of national intervention programs for street children in the province of Yogyakarta, Indonesia. A two-fold research methodology was employed, a combination of analyzing the pertinent documentation relating to policy and intervention programs along with interviews of key informants from government offices and non-governmental institutions. The current programs fail to address the root causes of the economic, political, and social barriers encountered by street children. National policies and programs are not intertwined with efforts of empowerment at the provincial and regional levels. To compound these deficiencies, adaptive strategies incorporating local culture, conditions, and needs are …  Lire la suite

Greenwood, Celia (Supervisor)  Lire la suite

A comprehensive two-dimensional simulation of the film blowing process is developed based on a mathematical model that incorporates the Phan-Thien and Tanner (PTT) and the Neo-Hookean constitutive equations with crystallization effects. The PTT constitutive equation is employed in the liquid-like region, while the Neo-Hookean constitutive equation is employed in the solid-like region, to describe the rheological behavior of the film. The effects of the process variables and parameters on the stress balance and overall behavior of the film were evaluated. The orientation-induced crystallization is accounted for by incorporating the Nakamura non-isothermal equation along with the Ziabicki equation. The proposed model …  Lire la suite

Current mainstream software engineering methods do not consider fault tolerance in the requirements engineering and analysis stage. If at all, they only address it much later in the development cycle. However, most modern systems can benefit from some form of fault-tolerance. Especially, complex, concurrent, distributed, or heterogeneous applications are likely to contain software design faults that can lead to system failures. In case of real-time or safety-critical systems, such faults can also result in catastrophes. This thesis aims to investigate whether software development approaches have integrated the concern of fault tolerance into the early software development stages to satisfy dependability …  Lire la suite

Repeated time series single case experiments were used to test if attachment-related interventions added to the efficacy of cognitive behavioural therapy (CBT) for treatment-resistant obsessive compulsive disorder (OCD) in two insecurely attached individuals. We developed a method for formulating cases with respect to attachment, and delineating specific, attachment-related interventions. The baseline treatment phase consisted of standard CBT and the intervention phase featured the addition of attachment-related interventions. Clinically significant change was assessed using Jacobson's method, and times series data was analyzed using overfitted ARIMA modeling. Both participants improved symptomatically with standard CBT. Attachment-related interventions did not add to efficacy of …  Lire la suite

This thesis addresses the problem of automatically detecting people from images. Our work is motivated by, and demonstrated on, an automated video surveillance application that aims to monitor people appearing in a scene. We adopt a machine learning-based approach to detection: first, a two-class classifier that can accurately distinguish cropped person images from all other types of images is automatically learned from examples. It is then used to spot instances of the person class within a given image. We have developed and implemented two detection systems using this approach. The first detector is based on the Viola-Jones object detection algorithm …  Lire la suite

Anthropometcic measurements and 24h-recall interviews were conducted on Dene/Metis and Yukon children, and food choice questionnaire interviews were conducted on the mothers of the children. On average, 32% of the children were above the 85th percentile of BMI-for-age in the 2000 CDC Growth Charts. The dietary nutrient intakes were compared to the DRI values. Vitamin A, calcium, phosphorus, vitamin D, vitamin E, dietary fiber, omega-6 fatty acids, omega-3 fatty acids, and magnesium intakes were low. Excessive nutrient intake was not observed. Imbalance of energy intake from carbohydrate and fat and excessive energy intake from total sugar and saturated fat were …  Lire la suite

Synaptotagmin I (Syt I) is thought to act as the calcium sensor during regulated exocytosis. We have discovered two novel splice forms of Syt I in the nervous system of Aplysia californica. In the first one, an alternative exon entry site adds two amino acids, V and Q, to the juxtamembrane region that separates the transmembrane domain from the first C2 domain. This splicing event is conserved over the evolution. Overexpression of this form, called Syt IVQ, blocked the ability of serotonin (5-HT) to reverse synaptic depression, while overexpression of Syt I did not. This effect was specific to the …  Lire la suite

The Canadian government introduced its Multicultural and Employment Equity policies in a series of attempts to induce federally-controlled institutions to reflect the racial diversity of the Canadian population in their programs and workforces. This is a case study of one institution's response to these policies. It examines the implementation of the six-year New Initiatives in Film (NIF) program begun in 1990 by the now-defunct women's filmmaking unit, Studio D of the National Film Board of Canada (NFB) and exposes the fault lines along which the goals of the NFB's various constituent parts clashed and meshed with the diverse goals of …  Lire la suite

Liberalization of textiles and clothing was one of the pillars of the Uruguay Round under the WTO aimed at promoting economic growth, development and alleviating poverty. For over 40 years this sector had been separated from the established principles of liberal trade stemming mainly from protectionist sentiments. The new regime established by the Uruguay Round aimed at integrating the sector into GATT on the basis of its strengthened rules and disciplines in furtherance of its general objective to liberalize trade. This change in international trade rules is a phenomenal development that is bound to have an impact on trade in …  Lire la suite

In this study I challenge the uncritical use of the long held dictum of the development discourse that education empowers women. From a post-structuralist feminist position I show that in its current state the educational discourse in Pakistan actually disempowers women. This discourse constitutes gendered identities and positions them in a way that exacerbates and intensifies inequalities between men and women. Gendered constitution and positioning of subjects also regulates the relationship between the subjects and the state in such a way that women and minorities are excluded from the citizenship realm. Educational discourse in Pakistan is the premier site where …  Lire la suite

Introduction. Programmed Death 1 is a molecule that becomes expressed on the surface of B and T cells once they are activated. Binding with its ligands, PD-L1 and PD-L2 which are found on T cells, antigen-presenting cells and peripheral tissues, causes inhibition of the PD-1-bearing cell. Knockout of the PD-1 gene in mice causes autoimmune nephritis, arthritis and cardiomyopathy. A study in humans demonstrated that an intronic SNP, named PD-1.3, is associated with lupus in several different populations. Studies on whether this polymorphism affects gene expression proved inconclusive and its biologic significance remains unknown. Methods. We began by sequencing the …  Lire la suite

Results on the development of Ni-based electrocatalysts for hydrogen evolution in an acidic medium are discussed in the thesis. This topic is of a great importance for the development of a PEM-type hydrogen generator, as a global initiative for the development of clean sustainable energy systems. A number of experimental techniques were used in research: linear dc polarization (Tafel), electrochemical impedance spectroscopy (EIS), potential-decay, inductively coupled plasma (ICP), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The first part of the thesis discusses the results on the influence of alloying nickel by left-hand side transition metals (Fe, Mo, W) on …  Lire la suite

Methylenetetrahydrofolate reductase (MTHFR) catalyzes the reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, a substrate for remethylation of homocysteine to methionine. Methionine is then converted to S-adenosylmethionine (SAM), the universal methyl donor. In the mouse, MTHFR levels are highest in the testis and mice deficient for a targeted mutation in the Mthfr gene are infertile. Analysis of prenatal gonocyte development provided evidence that the defect in the Mthfr mouse testis occurs shortly after birth. The expression profiles at the mRNA and protein levels suggest that Mthfr is expressed in the male germ line and is developmentally regulated, with a possible role in meiosis. …  Lire la suite

Population-based molecular epidemiologic studies of tuberculosis have been widely performed to assess the burden of ongoing TB transmission within a population. By genotyping M. tuberculosis isolates (M.TB), cases with matching DNA "fingerprints" are inferred to be due to ongoing transmission, and those with non-matching or "unique" fingerprints are inferred to represent re-activation disease. Two population-based molecular epidemiologic studies using three genotyping methods (IS6110 RFLP, spoligotyping and MIRU) are presented here. The first study examines all TB cases among the Inuit community if Nunavik, Quebec (1990-2000). Our analysis identified previously unrecognized inter-village transmission and estimated that at least 65% of TB …  Lire la suite

Graft copolymers using biodegradable and biocompatible bacterial poly([ R]-3-hydroxybutyrate) blocks were synthesized and tested as biomaterial candidates for orthopaedic surgery applications. Low molecular weight poly([ R]-3-hydroxyalkanoates), namely poly([R]-3-hydroxybutyrate), poly([R]-3-hydroxyvalerate), and their copolymers poly([ R]-3-hydroxybutyrate-co-[R]-3-hydroxyvalerate), were prepared by thermal degradation in the melt at 190°C. The chemical composition of the oligomers was well-defined, featuring the same repeat unit as their high molecular weight analogues, a carboxylic acid end, and an alkenyl end mostly in the trans configuration (crotonate-type). Increase in the reaction temperature, time, or [R]-3-hydroxyvalerate content decreased the molecular weight of the products. Methacrylic macromonomers of PHB were obtained by …  Lire la suite