VictorJuiz/thesis huggingface dataset:
The development and characterization of degradable, segmented polyurethanes containing amino acid-based chain extenders

Degradable segmented polyurethanes were attained through the incorporation of experimental amino acid-based (L-phenylalanine and L-lysine), ester containing chain extenders. The phenylalanine-based chain extender was synthesized and purified to a good final yield (~45%). A protected form of L-lysine (N-[epsilon]-carbobenzoxy-L-lysine) was used to avoid unwanted crosslinking reactions during polymerization. Difficulties with low yield (~1%) and incomplete diesterification of the lysine-based chain extender were mitigated by alteration of the linking diol chemistry. A low toxicity L-lysine-based diisocyanate (2,6-diisocyanato methyl caproate, LDI) was used to synthesize the degradable polyurethanes. The effect of soft segment type (polycaprolactone diol, PCL and polyethylene oxide, PEO) and chain extender type and content on physicochemical properties was evaluated. The polymers ranged from completely amorphous to semicrystalline. Tensile strengths varied from 1.0 to 30.8 MPa. Bulk hydrophilicity ranged from water soluble to 1.3% water uptake, depending primarily on soft segment chemistry and content. Generally, the PEO-containing polyurethanes were weak, hydrophilic materials while the PCL polyurethanes were strong, hydrophobic elastomers. The carbobenzoxy (CBZ) protecting group of the L-lysine ester chain extended polyurethane was removed by hydrogenolysis. Nuclear magnetic resonance spectroscopic analysis indicated that deprotection resulted in a 37 mol% reduction in CBZ content. However, deprotection resulted in backbone urethane cleavage leading to reduced molecular weight and loss of hard segment. The 'in vitro' degradation properties of the polyurethanes were studied in buffer and enzyme solutions to evaluate the susceptibility to passive and enzymatic hydrolysis, respectively. Inclusion of amino acid-based chain extenders conferred enhanced susceptibility towards enzymatic attack by two model enzymes (chymotrypsin and trypsin) and increasing chain extender content led to increasing enzymatic erosion. Enzymatic degradation and erosion proceeded via a surface-limited mechanism, causing little change in bulk properties. The magnitude of erosion was enzyme-dependent, making it possible to tune erosion based on the enzyme profile at the application site. Lastly, the 'in vitro' cytocompatibility of the polyurethane degradation products generated during buffer incubation was evaluated by MTT assay. The polyurethane degradation products were not found to elicit a significant cytotoxic response (<75% cell viability) for any exposure time suggesting that the polyurethanes may be useful for biomedical applications.
Mining for empty hyperrectangles by way of data reduction techniques

In this thesis, we study the problem of mining for empty hyperrectangles in a bounded space containing point objects. Our focus is on identification and pattern evaluation. Current methods that mine and analyze empty hyperrectangles are infeasible and ineffective. Instead, we develop efficient and effective solutions by way of data reduction techniques. We introduce a two-step method to mine for maximal empty hyperrectangles approximately. We develop the rectangle feature (RF), RF-tree, and a hierarchical clustering algorithm which computes an RF-summary of a dataset that is guaranteed to be main memory resident. We develop a simple algorithm which finds empty hyperrectangles that are maximal according to an RF-summary. Experiments on real datasets demonstrate the quality and performance of our approach. To analyze empty hyperrectangles, we adapt a greedy heuristic for the maximum coverage problem, and examine empty hyperrectangles in approximately order of decreasing incremental coverage. Experiments demonstrate its practicality and effectiveness.
Metallothionein III and S100ß modulate neuronal activity and survival

Alzheimer's disease (AD) is the most common form of dementia and is characterized at postmortem by the deposition of amyloid plaques and intraneuronal neurofibrillary tangles. Plaques are primarily composed of amyloid-ß (Aß) peptide, while tangles are assembled from abnormally phosphorylated microtubule associated tau protein. Both are morphologically fibrous structures and directly neurotoxic. These pathological events are accompanied by reactive gliosis and extensive neuronal loss leading to clinical dementia. The central focus of this thesis is that dysregulation of metal binding growth factors and their relationship to astrocyte function, contributes to AD pathogenesis. These studies focus on metallothionein-III (MT-III) and S100ß, which are zinc-binding factors with altered expression in AD. The role of these proteins was also assessed in conjunction with astrocyte function and its relationship to amyloid toxicity. MT-III is a potent inhibitor of neurite growth and a comprehensive examination was performed to determine its relative expression level in AD and control cases. Immunoblotting, histochemistry and analysis of mRNA levels revealed that MT-III is significantly reduced in AD tissue. Furthermore, nucleosome structure alterations suggested a non-functional MT-III promoter. Loss of normal inhibitory MT-III activity is proposed as a factor for abnormal neuritic sprouting observed in AD. Reduced MT-III may have additional consequences as demonstrated by its ability to sequester zinc and protect against the metal-induced aggregation and toxicity of the Aß peptide. As a counterpart to MT-III, S100ß induces neurite outgrowth and is significantly elevated in AD. We have shown that S100ß directly interacts with tau and that this binding is inhibited by the hyperphosphorylation associated within AD related neurofibrillary tangles. In neuron-like cells, S100ß was internalized and co-localized with intracellular tau, which was potentiated by the addition of exogenous zinc. Tau phosphorylation was unaltered but S100ß uptake was accompanied by extensive neurite outgrowth. This suggests that S100ß may regulate tau function and disruption of this pathway, either by changes in its expression level or metal imbalances, may contribute to the disease process. Astrocytes are key to S100ß and MT-III activity and they provide support for neurons under stress conditions. The role of astrocytes was examined we have ascertained that, with aging, these cells exhibit a diminished cytokine response and a reduced capacity to protect cells from amyloid toxicity. Similar effects are proposed to occur in aged individuals and lead to a greater susceptibility to neuronal loss. Overall, these studies indicate a number of pathways involving MT-III and S100ß that, along with their glial partners, can promote Alzheimer's disease-like pathological events.
Mechanism of drug release from matrix tablets involving moving boundaries

Drug release kinetics in relation to surface properties, liquid uptake behavior, and swelling and erosion of matrix tablets containing drugs of different solubility has been studied. Contact angle, liquid uptake and swelling kinetics were studied by goniometry, gravimetry and microscopy respectively The contact angle and liquid uptake depended on HPMC/lactose ratio and solubility of the drug. Drug release became sustained with increasing HPMC concentration, because of poorer wettability, slower hydration and formation of gelatinous layer. During hydration of the tablets, the movement of three distinct moving fronts namely swelling, diffusion and erosion fronts were observed. In the case of indomethacin tablets, the diffusion front moved outwards with the erosion front due to the presence of un-dissolved drug. The correlation between release rate and different characteristics of matrix tablets has been established based on the solubility of the drug and the ratio of HPMC to lactose.
Food security and peasants' survival strategy, a study of a village in Northern Shewa, Ethiopia

Ethiopia is an old agrarian society endowed with a skilled and hard-working peasantry that carries a rich fund of agricultural knowledge. Yet Ethiopian peasants have been the main victims of the cyclical droughts and famines. Recurring famines helped to bring about the 1974 revolution. Many radical reforms were introduced by the post-1974 regime with the aim of giving peasants more economic and political power, increasing agricultural productivity and ending, agrarian poverty. The reforms sought to achieve a radical break with the past. The thesis analyzes the impact of these changes on the peasants. It shows that the negation of local initiative and traditional knowledge and institutions, rather than strengthening the peasantry, weakened their survival capacity and made them more vulnerable to crisis. The severity of the 1984-85 famine is viewed in this context. The central argument of the thesis is that peasants' marginal political and economic position hinders their ability to adapt to rapidly changing, social conditions. In the past, their subordination to landlords and the state perpetuated poverty and limited their capacity to cope with crises. Their continued political and economical subordination continues to prevent them from overcoming rural poverty. Combining political economy and oral history, this study traces the spontaneous migration of peasants from the overpopulated area of Wello to the sparsely populated region of Northern Shewa in search of land. It shows how the migrants creatively combined their knowledge of the past with hard work and technical, political and social ingenuity to adapt to the socially and ecologically diverse environment of the new region in pursuit of a livelihood. The thesis elucidates how peasants use their material and non-material resources and past experiences with droughts and famines to innovate survival strategies. It stresses that peasant resourcefulness needs to be supported and encouraged for the sake of long-term, sustained development. A development policy, utilizing peasants' initiative and local resources is an effective substitute for state reforms imposed from above or occasional food relief by outside agencies.
To evaluate differences in mRNA expression of c-fms, EP2 and EP4 between large and small osteoclasts

Osteoclasts play a primary role in bone resorption. These cells are heterogeneous with respect to their size and resorptive ability. Since a greater proportion of large osteoclasts are resorbing compared to small osteoclasts in the same rabbit long bone cell cultures, we hypothesized that differences in the expression of receptors for cytokines, such as Macrophage Colony Stimulating Factor (MCSF), or other osteoclast activating factors, such as prostaglandins, may account for these differences in resorptive activity. We decided to test this hypothesis by starting to evaluate differences in c-fms (MCSF receptor), EP2 and EP4 (prostaglandin receptors) mRNA expression between small and large osteoclasts, using 'in situ' hybridization on isolated newborn rabbit osteoclasts. There was a significant difference in c-fms mRNA expression, measured as mean grains/nucleus, between large and small osteoclasts. Large osteoclasts from both endochondral and intramembranous bone had a greater mRNA level for c-fms than did small osteoclasts (p < 0.01). No labeling was detected with the EP2 and EP4 RNA probes. Assuming that differences in mRNA expression for c-fms between small and large osteoclasts from both endochondral and intramembranous bone represent differences in the expression of the receptor protein, the results suggest that large and small osteoclasts could indeed be activated to a different degree by MCSF.
A qualitative analysis of the experiences of partners of problem gamblers

This qualitative study sought to explore the experiences of partners living with their spouses who were ongoing problem gamblers. Seven female and three male partners involved in relationships between 18 months and 33 years were interviewed about their experiences and coping strategies. Key themes that emerged were concerns about finances, pronounced feelings of loss, self-reflection and mixed feelings about staying together. These partners coped by creating a separate life apart from their relationship with their gambling spouse. These findings suggest partners demonstrate the ability to take care of themselves rather than see themselves as victims. Practice implications include building on strengths while encouraging partners to prioritize their own needs regardless of the gambling involvement of their spouse.
Effect of substrate properties on molten metal droplet impact

The impact of molten metal droplets on a flat surface was studied experimentally. A single shot photographic technique was used to photograph droplet impact, and the spread factor and number of fingers around a splashing drop were measured from these photographs. Experiments were done using stainless steel and glass substrates with different roughness. The stainless steel surface temperature was varied from 25°C to 240°C. The initial temperature of tin droplets was maintained at either 246°C or 384°C. Some experiments were done on the impact of molten zinc droplets. A simple energy conservation model was used to estimate the thermal contact resistance between the droplet and surface. Increasing surface roughness was found to increase thermal contact resistance. Increasing surface roughness reduced the number of fingers while increasing their size. When one droplet lands on another, the final splat shape depends on the distance between droplet centers.
Effect of exposure conditions on leaching of chromated copper arsenate, CCA-C, from treated wood

This thesis examines chromated copper arsenate (CCA) leaching from treated wood exposed to natural rain and laboratory leaching. Lumber specimens were subjected to 685 mm of precipitation during 351 days of exposure. Leaching rates ([mu]g/cm2) of chromium, arsenic, and copper were similar for the three species evaluated (jack pine, black spruce, and southern yellow pine). Application of a water repellent reduced leaching losses by approximately 50%, while a post-fixation pressure washing treatment had mixed effects. Regression analysis revealed that 30% of the variation in chromium and arsenic leaching, and 44% of the variation in copper leaching was explained by sample treatments and climatic variables. A comparison of laboratory leaching methods reveals the need for harmonization of current standards. The American Wood Preservers Association Standard (AWPA E11-97) displayed the highest leaching, followed by the European Standard (EN-84), an independent test, and a method developed by industry. Percent loss from the laboratory leaching standards greatly overestimated leaching from 351 days of above ground exposure. Less than 5 hours of AWPA E11-97 leaching, and less than 21 hours of EN-84 leaching were required to leach the equivalent amount as 351 days of above ground exposure.
Multiple mechanisms of regulating glucose transporters and glucose transport in skeletal muscle cells

Glucose is a universal energy substrate of mammalian cells. The Thesis examines the two main pathways of regulating glucose transport in muscle cells--insulin and the metabolic demand pathway. Insulin and the mitochondrial uncoupler dinitrophenol (DNP) were used to stimulate these two pathways in L6 muscle cells in order to dissect differences involving 3 major cellular regulatory pathways: (1) the actin cytoskeleton and temporal spatial regulation of signals and glucose transporters; (2) signalling pathways activated by these stimuli; and (3) cellular mechanisms controlling chronic glucose transporter expression. The results demonstrate that insulin provokes a rapid and marked aggregation of filamentous actin into structures that provide the coordinates for the insulin-derived signals to meet glucose transporter organelles, and direct their insertion into membrane ruffles. The results also reveal that, in contrast to insulin, DNP-stimulated glucose uptake largely depends on cytosolic Ca2+ and Ca2+-sensitive PKCs, but likely does not engage the fuel sensing enzyme AMPK. Finally, insulin and DNP were shown to elicit different long-term effects on glucose transporter expression: whereas prolonged exposure to insulin increases glucose transporter biosynthesis, chronic exposure to DNP increases the half-life of the glucose transporters in an isoform-specific manner. By uncovering the different cellular factors accessed by insulin and DNP to control glucose transport, the Thesis enhances our understanding of the diverse means employed by the muscle cell to control glucose homeostasis, and may have implications for the therapeutic treatment of diseases associated with impaired glucose utilization, such as Type 2 diabetes.
From college to Constable, is a diploma an occupational necessity?

This dissertation focuses on post secondary education, and in particular the Law and Security Administration Diploma (LASA) in the community colleges and its educational and training impact as well as its characterization by municipal police services within the Province of Ontario. The research examines the relationship between the level of education and attitudes and opinions towards professionalism and militarism. Some evidence indicates that enhanced formal education and rank champions pro-educational endorsement. However, on balance, the merit of obtaining post-secondary education and its occupational relevance are not a high priority. Interestingly, education becomes unimportant when striving for greater professionalism. Gaps become apparent between practise and rhetoric. This said, and unlike Dalley (1975), the degree of exposure to post-secondary education corresponds with a notable domination of militaristic perspectives. The notion of the quasi-military police infrastructure with large numbers of men sustaining hegemony still lingers as a central feature in policing. Likewise, it appears Constables with enhanced education become more dissatisfied with police careers. The research suggests female Constables' disposition maintains a significant positive relationship on the organization in relation to opinions on pre-employment educational credentials and personal educational attainment. Like Guller's (1972) investigation, education reflects professional attitudes with respect to female Constables. The research encourages colleges to cultivate and augment their post secondary program to more than satisfy both the academic and policing communities. The research also beckons police personnel to advocate the need for enhanced educational standing. Police services should be securing a more sufficient share of the better educated recruits. Integrated post secondary education and police learning should be matters of formal policing. Recommendations are made to the Solicitor General, police services through structural reform by way of a "Millennium Management Style," College administrators and educators.
Physiology, geology and geochemistry of the southern Explorer Ridge seafloor hydrothermal site using an integrated GIS database and 3D modeling

Southern Explorer Ridge (SER) is an anomalously-rate shallow, intermediate spreading ridge located 200 kilometers off the west coast of Vancouver Island, Canada. It ranges in depth between 2600 and 1760 meters. For the first time, geological, geochemical and geophysical data collected from 15 cruises to SER have been assembled in a GIS format. The distribution of published K/Ti ratios and Mg Three-dimensional modeling of Seabeam bathymetry and SeaMARC sonar data has provided enhanced visualization of SER. Physiological features make SER comparable to an elongate seamount. Specific morphological characteristics indicate that summit trough formation and evolution at SER result from non steady state processes.
Stray current corrosion of carbon steel, electroplated nickel, and electroless nickel in an alkaline environment

The stability of metal parts in electrolytic environment is a function of external and internal cell field bias. Therefore, in order to achieve long-term integrity of electrolyser cell components, the alloys and plated metals used should be evaluated with respect to stray current corrosion. For this purpose, three different materials were tested in this study in specially designed electrochemical cells. The materials were carbon steel, Ni-electroplated carbon steel, and electroless Ni plated on carbon steel. In this comparative study, the corrosion of the three materials was investigated using both thermodynamic predictions (Pourbaix diagrams) and potentiostatic and weight loss data obtained from immersion testing for the three materials. Effects of turbulence, hydrogen gas, and temperature variation on corrosion were also examined for the above materials. Finally, electroplated Ni and electroless Ni plated carbon steel showed excellent resistance to stray current corrosion under the specific electrolyser conditions.
The physicality of mind and the problem of free will

It is my thesis that a person who is convinced of possessing unequivocal freedom of will has indeed underestimated the extent to which psychic determinism governs human mental life. Free will of this kind would be conceptually plausible if and only if mind is disengaged from body. I aim to introduce more order and explicitness than at present exists into mind body analyses and the problem of free will. My aim determines my material, which is primarily concepts and their referents. My method is chiefly meta-psychophilosophical scrutiny and the ordering of concepts. Although I will primarily be concerned with the evolution of ideas regarding mental causality, consideration of the antitheses mind body, unconscious-conscious, free will-determinism is unavoidable. It will make for easier discussion to begin by contrasting and comparing these concepts with one another. My intent is to mitigate the tensions amongst various conceptions of mind and body within the larger conceptual framework of causality.
War and nationality conflict in Eastern Galicia, 1914-1920: The evolution of modern anti-Semitism

World War I and its immediate aftermath in Eastern Galicia witnessed the most brutal persecution of Jews. In 1914-1915 the Russian army brutalized, uprooted, and forcibly displaced thousands of Jewish civilians for their alleged collaboration with the Central Powers. Between 1918 and 1920, the formation of the new Polish state was accompanied by numerous anti-Jewish riots and pogroms by mobs and undisciplined soldiers. Such a treatment of a minority group in wartime poses two crucial questions--how do we explain the mechanisms of intolerance and persecution? and why would a state or a dominant society feel threatened by a numerically smaller group? The present study addresses itself to these questions. There have been numerous attempts to explain the causes of ethnic conflicts and, especially, the antecedents of anti-Semitism. Some sources have focused on traditional, "ancient" resentments towards Jews as driving forces of ethnic violence; others have suggested that power holders skillfully redirected their subjects' economic and social frustrations on a disliked minority. While such arguments offer a valid insight on the issue, it is my contention that ethnic persecution involves more crucial issues than age-old hatreds and cynical manipulation of power. I argue that the following factors--social or political crisis, collective fears of an allegedly dangerous minority, security concerns of a militant leadership, exclusionary nationalism, and attempts of a minority group to mitigate persecution by active political participation--render ethnic conflict particularly acute. Focusing on these factors, I attempt to provide a broad framework for understanding how various causes of ethnic conflict fit together and interact.