VictorJuiz/thesis huggingface dataset:
Regulation and activity of cell cycle control factors in terminal cellular differentiation

Cellular differentiation is a process in which multipotent stem cells undergo a series of genetic events that limit the number of eventual cell fates. Terminal differentiation is one final stage, where a number of functional and phenotypic changes occur giving rise to a characteristic appearance and function. No further cell fate choices are available to terminally differentiated cells. In many cases the terminally differentiated cell is no longer capable of proceeding through the cell cycle, and arrests permanently in a quiescent G0 state. Investigations using a number of model systems have determined that there is remarkable conservation between species, at both the sequence and the structural level, of the regulatory factors which control passage through the mitotic cell cycle (for reviews see: (1-4)). Factors that regulate progression through the cell cycle are likely to be intricately involved in the process of terminal differentiation. In this thesis, I have investigated the regulation of cell cycle factors, and the functional role of these factors and their interactions, during cellular differentiation. We found that members of the E2F, pRB, cyclin, cdk, and CKI family proteins are regulated in both neuronal and myogenic differentiation through a series of overlapping regulatory mechanisms. These mechanisms include alterations in transcription, phosphorylation, protein stability, and sub-cellular localization, as well as changes in subunit composition of kinase and transcription complexes. The net effect of these overlapping regulatory mechanisms is to suppress levels of free, active E2F transcription complexes, allowing cell cycle exit and terminal differentiation to occur.
Functional dissociation of SAPK and apoptosis in epithelial and endothelial cells, implications for anoikis

Adhesion to the extracellular matrix is a crucial survival signal for epithelial and endothelial cells. The stress caused by detachment from the solid substratum activates an endogenous death program termed 'anoikis' in both cell types. The question then arises: does stress kill? The signaling events that culminate in anoikis are still unclear. Although recent studies have implicated Stress Activated Protein Kinase (SAPK), also known as Jun-N-Terminal kinase, as a potentially crucial signal transducer and mediator of anoikis, the generality and the causal role of SAPK in anoikis remains unclear and controversial. The work described here does not dispute that SAPK is activated by the loss of cell-ECM interactions, but serves to provide further support for the lack of causative effects this activation has in the overall phenomenon of anoikis. Ongoing studies investigating other possible regulators of anoikis have pointed to a number of different gene families. Foremost among them is the bcl-2 family, although newly discovered apoptotic regulators, such as the IAP family, may be involved in the anoikis abrogation of transformed cells. Overall, it would appear that anoikis regulation is a complex process regulated by numerous and possibly redundant signaling pathways, which may further exhibit cell specific variations.
Educating the African immigrant child in Canada, a study of how Ghanaian parents negotiate the home-school intersection

This dissertation is an exploratory study of minority African parents' involvement in the education of their children in a Canada. Situated within a framework which underscores notions of pluralism and inclusion, the inquiry utilizes case study methods to focus attention on the particular challenges that Ghanaian parents encounter as they negotiate the intersection of the home and school in the education of their children in Canada. The major finding of the study is that Ghanaian parents' lack of awareness about educational policies and school processes in Canada combines with the insensitivity of school officials to attenuate the potential contribution of the parents to the education of their children. The parents' attitudes and behaviors concerning their children's education are largely informed by their pre-immigration educational and socialization experiences in Ghana, and their daily lived experiences in Canada. But, institutional and teacher practices do not offer much support to parents because such practices are removed from the parents' experiences and are largely fed by the 'deficit thinking' paradigm. To maximize the contributions of Ghanaian parents to the education of their children in Canada, the finding points to the need to examine and interpret the relationship that schools maintain with Ghanaian families in the light of the parents' pre-immigration socialization experiences and present social, cultural and economic location within Canada.
Inset forms of art in the plays of Philip Massinger

This thesis examines the use of metatheatrical inset pieces in the work of Philip Massinger, the dominant professional playwright of the London stage in the reign of Charles the First (1625-1642). Although all Renaissance drama contains metatheatrical insets, the Caroline period is particularly rich in these devices. I examine Massinger's use of such insets to posit some reasons for the development of a peculiarly Caroline metadrama and to examine their dramaturgical function in his plays. Massinger's presentation of inset pieces focuses on their function as spectatorial objects--pieces of art which are interpreted by spectators--which permits him to theatrically examine the process of spectatorship, and thus, to analyse the process of theatre itself. The introduction maps out the Caroline theatrical landscape, surveying some of the potential causes for the development of self-reflexive drama in the period, and placing Massinger within this context; the thesis itself focusses on Massinger's use of four forms of inset art. The first chapter examines Massinger's staging of pieces of visual art--paintings and statues--as metadramatic insets, objects which are read by spectators on the stage. The focus of the chapter is the dramaturgical use of the miniature of 'The Picture' (1629); Massinger structures the plot of his play around Mathias's reactions to his 'readings' of this image. The second and third chapters examine Massinger's two types of inset masques; Chapter Two focusses on masques which are staged for a single on-stage audience, and which simply function as dramatic images. Chapter Three examines the masques of 'The City Madam' (1632) and 'A Very Woman' (1634), both of which are ostensibly staged for a single audience member, who is then watched by a second on-stage audience who judge his reactions to the show he sees. Both masques function, like the miniature of ' The Picture', to allow access to the interior of their spectators. The final chapter examines the plays-within of 'The Roman Actor' (1626), Massinger's metatheatrical analysis and defence of his stage.
The sensitivity and stability of hand-preference behaviour during infancy, a dynamic systems approach to the development of lateral preferences

A contemporary theoretical framework known as dynamic systems theory was used to examine longitudinally the sensitivity and stability of hand-preference behaviour in two infants over two developmental periods (ages 3.5 to 5.5 months, and ages 6 to 10 months). During these periods, reports of dynamic growth spurts in the development of the brain, and fluctuations in the development of hand preference, are well documented. The importance of this study rested upon the assumption that various neural subsystems within the brain were undergoing phase transitions during these periods, and that hand-preference behaviour would mirror these changes. The method of investigation involved requiring infants to use their dominant and nondominant hands for a series of reaches, and evaluating the effects with respect to dynamic systems principles of biological self-organization. Analyses of the results revealed that the hand-preference behaviour of both infants did appear to be developing in accordance with these principles.
Properties of organic iodides

A study is presented on the properties of organic iodides, emphasizing the Henry's constant within the temperature range of 25-75°C. The types of compounds studied were alkyl iodides, aromatic iodides, phenolic iodides, and iodoalcohols. The values measured ranged from 0.6 ± 0.1 for iodoheptane at 25°C, to 1.2 * 104 ± 500 for iodoethanol at 25°C. A new experimental method involving a stripping apparatus, and radioactively traced organic iodides was employed, and found to be efficient in the determination of Henry's constants. Various properties were determined for a large set of organic iodides through the use of models. Concerning the modeling of the Henry's constant, two calculation methods were examined. The first method analyzed involved equating the Henry's constant to the ratio of aqueous solubility and vapour pressure, and then using excess enthalpies of solution and vaporization to estimate the temperature dependence of the Henry's constant. The second method was the utilization of structural bond contributions. The first method was found to be accurate for most of the organic iodides tested, while the second was found to be totally reliable only within the range of alkyl iodides.
Effect of microdomain structures on the enzyme induced hydrolytic degradation of polycarbonate-urethanes

Polycarbonate urethanes (PCNUs) have been used as a replacement for traditional biomedical polyether-urethanes due to their enhanced resistance to oxidative biodegradation. However, relatively little is known about their hydrolytic stability in the presence of inflammatory derived enzymes. This has in part motivated the work of this thesis, which probes the nature of the cholesterol esterase (CE) catalyzed hydrolytic degradation processes in PCNUs. A series of model PCNUs with different micro-domain structures were synthesized, by changing their hard segment size and chemistry. The polymer bulk structures were characterized with gel permeation chromatography (GPC), differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), Fourier transform infrared spectroscopy (FTIR) for their bulk structures. The surface properties of the polymers were analyzed with contact angle, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). 14C-labelled PCNUs were incubated with different CE concentrations, for a period of ten weeks (pH 7.0 at 37°C), and radiolabel counting was used to monitor the degradation. The nature of the degradation products was assessed by high performance liquid chromatography (HPLC) and mass spectrometry (MS). The results showed that all of the PCNUs synthesized in this study were susceptible to CE catalyzed hydrolytic degradation, and that the extent of degradation was highly dependent on the nature of hard segment interactions in the polymer and at the surface. The nature of the degradation process was defined by the following features, (1) the amount of each group located at the surface and at the interface of the soft/hard segments, (2) the crystallinity of the hard segments and, (3) the degree of hydrogen bonding between the carbonate and urethane groups, as well as the inter-urethane groups. The latter factor appeared to be most influential. Despite its relative stability, the MDI based polymer was the only material which produced a diamine product (i.e. methylene diamine, MDA). The findings have important implications in defining a clear understanding of biostability for biomedical polyurethanes, specifically at the molecular level, and in describing the manner by which the body's enzymes disassemble these macromolecules over time.
Characterization of novel G protein-coupled receptor genes and the novel ligand apelin

G protein-coupled receptors (GPCRs) make up the large family of integral membrane bound proteins which mediate the signaling of extracellular stimuli to intracellular responses via activation of heterotrimeric G proteins and their subsequent interaction with effector proteins. GPCRs have been implicated in a number of physiological functions including behaviour, homeostasis, cognition, appetite, and drug addiction. This thesis describes the molecular characterization of the human and rat genes encoding apelin, the cognate ligand for the APJ receptor. Human and rat DNA sequences encoding apelin were retrieved by a search of the GenbankTM databases, their full length sequences cloned and used as probes for expression analyses. Comparative sequence and tissue distribution analyses revealed both apelin and the APJ receptor to resemble the angiotensin II peptide and the angiotensin II receptors, suggesting roles in similar physiological systems. In addition, a degenerate PCR strategy, database searching and the patent literature revealed DNA sequences encoding novel GPCRs, namely the thyrotropin-releasing hormone receptor TRH-R2, orphan GPCRs GPR54, GPR57, GPR58, GPR61, GPR62 and a pseudogene, WGPR57. With the initial discovery of each of these sequences, full length GPCR-encoding sequences were determined and used for mRNA distribution analyses by northern blot and in situ hybridization. In addition, novel GPCR-encoding genes were localized to chromosomes by fluorescence in situ hybridization (FISH) and expressed for pharmacological characterization.
Detection of incipient slip in child-sized myoelectric hands

This thesis is a continuation of research and development done at Bloorview MacMillan Centre in the area of slip detection for children's myoelectric hands. This project took the research into a new and more practical direction, bringing the concept closer to clinical implementation. Initial work in this project was based on addressing concerns and recommendations laid forth by previous researchers in the field. The first issue that was addressed was the motor that powered the hand. Previous work used a large, low-geared motor. This research tested the characteristics of the original, small, highly geared motor used in a clinical prosthetic hand, and allowed the slip detection system to work with this motor. The next issue looked at was the use of compliant fingertips with the slip detection system. The use of piezoelectric polymer (PVDF) slip sensors allowed for compatibility with compliant fingertips, whereas earlier research used incompatible piezoelectric ceramics (PZT). These new sensors also allowed for the slip detection system to work in the presence of a cosmetic PVC glove, which was previously a clinically limiting problem. Analogue signal processing circuitry was built to allow for electronic miniaturization for housing within the prosthetic hand. The circuit was designed to minimize noise from electromagnetic interference and from external non-slip mechanical vibrations. The effect of sensor placement and positioning was tested for optimal noise cancellation. The complete slip detection system was built and tested with a real-life slip situation, and was shown to react to slip satisfactorily. While much of the noise from external vibration was reduced, some response was seen to this noise under certain test conditions. Other test conditions showed little or no response to noise. The system's response to slip was better with the cosmetic glove on.
Identifying information-bearing prosodic parameters in severely dysarthric vocalizations

This thesis consists of two experiments designed to further our understanding of prosodic control in dysarthria. Speakers with severe dysarthria are known to have reduced range in prosody. Consistent control within that range, however, has largely been ignored. We investigated whether eight speakers with severe dysarthria due to cerebral palsy could control prosodic parameters for sustained vowel and phrase productions. In Experiment I, speakers were able to consistently control sustained production of the vowel /a/ at three distinct levels of duration (short, medium and long). Speakers were more variable in their ability to control distinct levels of pitch (low, medium and high). Nonetheless, seven of eight speakers were able to produce two distinct pitch levels. In Experiment II, we studied whether speakers could vary prosodic cues in phrase level productions. The task was to produce ten unique three-syllable phrases as questions and statements. We inferred the speakers' ability to control prosodic cues by asking a group of 48 naïve listeners to classify dysarthric productions as either questions or statements. Our results indicated that listeners were able to distinguish questions from statements with approximately 87% accuracy. Removal of pitch contour cues from the original recordings dramatically reduced listener accuracy scores to almost chance performance. We can infer that listeners found pitch contour to be an information-bearing prosodic cue in severely dysarthric vocalizations. Some speakers may have also been using syllable duration and loudness cues to mark the question-statement contrast. These findings provide a novel and significant step toward a more complete understanding of the prosodic control abilities of individuals with severe dysarthria. The potential implications for influencing diagnostic and intervention protocols are far reaching. Systematic exploration of the speaker's prosodic control abilities would enable clinicians to develop appropriate treatment regimes to optimally shape residual abilities for the purpose of enhancing communication. This line of research may also guide the development of voice-driven assistive aids that harness information within the prosodic channel.
The effects of constant vs. interval load training at and about the first ventilatory threshold on endurance performance indicators

Thirteen sedentary subjects (five males and eight females) were randomly assigned to a constant load (CT) or interval load (IT) group. Exercise training corresponded to an intensity at or about the first ventilatory threshold (Tv1). The CT group increased V¤O2max from 33.2 (±3.5) ml·(kg·min)-1 to 40.1 (±4.3) ml·(kg·min)-1, and Tv 1 from 19.2 (±2.9) ml·(kg·min)-1 to 24.7 (±1.8) ml·(kg·min)-1, after eight weeks. The CT group increased V¤O2max from 31.6 (±8.9) ml·(kg·min)-1 to 38.8 (±7.3) ml·(kg·min) -1, and Tv1 from 17.7 (±4.4) ml·(kg·min) -1 to 22.8 (±4.7) ml·(kg·min)-1 . These changes were significant. Between group differences for endurance performance improvements could not be detected after training, though there appeared to be a possible difference in the time course for adaptation, which could not be resolved with significance due to insufficient sample size. Conclusive statements regarding the effects of exercise training on the 'breath sound check' method of monitoring exercise intensity will require further research. The choice of CT vs. IT protocols in the training of sedentary persons will likely come down to subject preference.
Environmental politics and the Reagan administration, interests, ideas and values in international leadership

This dissertation is a comparative case study of the Reagan administration's approach to acid rain deposition and ozone layer depletion during the 1980s. The concern of this study is with the wide policy divergence that developed as this administration responded to these two environmental problems. Examining the historical record, we see that the United States took an international leadership role in efforts to create a CFC regime but resisted all attempts to forge an agreement aimed at controlling acid rain. This dissertation focuses on the interplay between scientific ideas, societal interests and decision maker values and how they shaped the policy processes that developed around these issues over time. The concepts of scientific consensus, policy network, critical event, and value shift help to structure our understanding of why this administration responded to the threat of ozone depletion so aggressively but did little to reduce acid rain. The interest group approach reveals to us the ways that pluralist forces increased the capacity of the United States government to regulate CFCs and reduced its ability to address acid rain deposition. The focus on decision maker values captures important nonrational individual level inputs into policy making that, heretofore, have not been the purview of International Relations theory. The investigation of epistemic community theory revealed fundamental weaknesses with this approach but provided an important starting point for understanding how ideas mediate between, and interact with, interests and values to affect policy formulation in the state. This dissertation concludes by arguing that, given the special character of environmental issues in the international political system, a unique approach to these problems that links ideas, interests and values will be required to fully understand them. This type of approach greatly expands our understanding of the acid rain and ozone layer cases and also shows great potential for examining the current efforts by the international community to respond to climate change.
Molecular genetic study of serotonin system genes in attention deficit hyperactivity disorder (ADHD)

Attention Deficit Hyperactivity Disorder (ADHD) is a childhood disorder marked by persistent patterns of inattention and hyperactivity/impulsivity, causing impairment in academic, social, and emotional development. Several lines of evidence have implicated the serotonergic system in behavioural inhibition and hyperactivity. Furthermore, serotonin exerts a significant degree of regulatory control over dopamine activity, suggesting that an imbalance between the two systems may be responsible for the development of ADHD. We tested for linkage disequilibrium between serotonin system genes (HTR2A, HTR1B, HTR1D, SLC6A4, TPH) and childhood ADHD using the Transmission Disequilibrium Test (TDT). Results revealed preferential transmission of the HTR2A 452Tyr allele to the affected offspring, suggesting linkage disequilibrium of this polymorphism with ADHD. A trend towards linkage disequilibrium of the HTR1B G861C polymorphism with ADHD was noted which may be of paternal origin. A quantitative TDT (QTDT) analysis revealed no evidence for linkage disequilibrium between the HTR2A and HTR1B, receptor genes and the continuous hyperactive/impulsive or inattention symptom dimensions of ADHD. These findings are suggestive for a serotonin component to ADHD pathophysiology that may open new doors towards a multi-system theory in ADHD genetics research.