VictorJuiz/thesis huggingface dataset:
Design and analysis of a low-temperature oxygen-fuel spray system

The present work presents the first effort to develop and analyze a low-temperature oxygen-fuel (LTOF) thermal spray system. The LTOF system can spray powder materials at controllable, moderate temperatures (800--2500 K). Temperature regulation is achieved by mixing combustion products with cold nitrogen. By combining numerical and experimental approaches, the author performed a detailed study of the LTOF process which involves complex chemical and fluid dynamic phenomena. Emphasis was put on the gas and particle dynamics in the LTOF spray process. Effects of various torch designs and operating parameters on torch performance were investigated. A one-dimensional simplified model of gas dynamic spray was established for quick prediction of particle conditions at the nozzle exit. Using the one-dimensional model, effects of major operating parameters (gas inlet pressure and temperature), particle size, and nozzle geometry on particle acceleration and heating were investigated. The one-dimensional analysis provided a basic understanding of particle behavior in a supersonic flow and was used for selecting parameters (gas flow rates, chamber pressure, nozzle geometry etc.) of the LTOF process. A comprehensive numerical model, using the Fluent CFD code, was developed to simulate the LTOF process. Both the internal flow and external flow were included in the simulation. A global reaction mechanism taking account of the dissociation of combustion products was used to model the combustion of methane in oxygen. Gas and particle dynamic characteristics of the LTOF spray were analyzed. The effects of gas flow rates, torch geometry, powder injection location, and total power on in-flight particle state were investigated as well. Key design considerations of the LTOF system were discussed; a set of design equations were proposed and used for building the LTOF system. Based on modeling results, engineering calculations and spray tests, a LTOF spray system was built. Performance of the LTOF spray system was evaluated by monitoring in-flight particle velocity and examining coating microstructure. Experimental results have demonstrated that the LTOF system can spray particles at various temperatures without noticeable drop in particle velocity. The advent of the LTOF system makes it possible to spray powders at temperatures engineered to specific powder material and mean particle size.
A fast filtering engine for publish/subscribe system

The current trend in the distributed systems is moving away from tightly-coupled systems towards systems of loosely-coupled, dynamically bound components. Due to the demands of modern applications, the popularity of Content-based publish/subscribe systems is rapidly increasing. However, one of the principal challenges faced by the publish/subscribe research community is to design an efficient matching algorithm for a flexible subscription language. To date, matching algorithms developed for publish/subscribe systems sacrifice subscription language expressiveness for matching performance. For example, almost all state-of-the-art matching algorithms can only support conjunctive subscriptions and many allow only equality predicates. In this thesis, we develop and evaluate a new matching algorithm that can handle any free form expression over a number of predicates. We also propose two extensions to our basic algorithm that can give additional performance benefits at the cost of a slightly restrictive subscription language. Our performance results demonstrate that the algorithm can achieve substantial event processing rates for very large number of subscriptions processed in the system.
Development of an inducible expression system for Bone Morphogenetic Proteins (BMPs) in mammalian cells

Bone morphogenetic proteins (BMPs), due to their ability to induce bone formation and stimulate osteogenic differentiation, are used in tissue regeneration procedures. However, current BMP applications are thwarted by several shortcomings that could theoretically be addressed by the development of a regulatable expression system to produce BMPs from genetically engineered, transplanted cells "on demand". Such an inducible expression system was developed in this thesis on the basis of tetracycline-inducible vectors. In initial experiments, a commercially available two-component expression system did not result in any inducible BMP expression from a large number of transfected and selected MEF/3T3 and C3H10T1/2 clonal cell lines. Only the use of an improved, single episomal expression vector (pRTS1) resulted in several clonal cell lines that showed significant induction of BMP2 expression upon stimulation with doxycycline. Induction kinetics and functional assays confirmed the potential usefulness of these genetically modified cells in regenerative procedures of bone.
Dexamethasone stimulation of osteoprogenitor differentiation in adult rat bone cell populations is mediated in part through an increased response to insulin-like growth factors

I have tested the hypothesis that dexamethasone (Dex)-stimulated osteoprogenitor differentiation in rat bone cell populations is mediated, in part, through the insulin-like growth factor (IGF) system. Since osteoprogenitors and adipocyte progenitors are believed to originate from the same precursors and their differentiation has been shown to be reciprocally regulated, the effects of Dex and IGFs on adipocyte formation were also evaluated. Vertebral bone cells from 3-month-old female rats were cultured for up to 20 days with or without Dex. IGF stimulation of osteoblastic colony formation was Dex-independent, whereas IGF stimulation of adipocyte formation was Dex-dependent. Dex alone did not induce adipocyte formation. An anti-type I IGF receptor (IGF-1R) antibody blocked Dex-induced osteoprogenitor differentiation, but did not affect adipocyte formation, suggesting that Dex stimulation of osteoprogenitor differentiation is mediated through the IGF-IGF-1R axis and that although an increased IGF response is involved in Dex stimulation of adipocyte formation, the signaling is not via IGF-1R. Northern and RT-PCR analyses at various time points showed that mRNA levels of virtually all the components of the IGF system were changed after Dex treatment. Interestingly, both IGF-I and IGF-1R mRNA levels were lower in Dex-treated cultures. To explain the discordance between these findings and the increased IGF responses in Dex-treated cultures, I examined the possibility that the increased IGF responses result from reduced inhibition of IGF action by IGF binding protein-4 (IGFBP-4). Protein levels of IGFBP-4 were lower in Dex-treated cultures than in controls at all 4 time points tested as shown by Western blotting, although IGFBP-4 mRNA levels were lower at day 14 but higher at day 20 in Dex-treated cultures than in controls. Proteolysis analysis showed that conditioned medium (CM) from Dex-treated cultures was more effective than CM from controls in degrading exogenous IGFBP-4, and that the proteolysis could be blocked by pre-incubating CM with an anti-pregnancy associated plasma protein-A (PAPP-A) antibody. These findings suggest that reduction of IGFBP-4 protein levels via increased proteolysis by PAPP-A appears to be the main mechanism whereby Dex increases IGF responses.
Diffusion and equilibrium amount of polyethylene glycol in wood cell walls

Diffusion and equilibrium amounts of polyethylene glycol (PEG) in the cell walls (CWs) of red pine sapwood were studied as a function of molecular weight (MW) of PEG, wood moisture content, and solvent properties. Relative amounts of PEG in the CWs were determined by Raman microscopy, and by extraction of PEG-treated wood with toluene. The study confirmed penetration of high MW (PEG 20000) into the CWs by scanning transmission electron microscopy coupled with energy dispersive X-ray analyzer (STEM-EDXA) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). A trend to higher concentrations of PEG in the middle lamellae was observed. ToF-SIMS was shown to be more appropriate for determining penetration of high MW PEG. Solvent properties, such as wood swelling ability and affinity for PEG were shown to be important factors determining PEG penetration into the CWs. Samples treated with PEG from chloroform solution adsorbed less PEG into the CWs than samples treated with PEG-water solution. These results were in agreement with the relative amounts of PEG measured by Raman microscope, which was shown to be a useful tool for quick and sample-preparation-free estimation of PEG in the CWs. Increase in ambient relative humidity caused movement of PEG from cell lumens to cell walls. Samples treated with lower MW PEG showed better CW impregnation, both when treated with nominal PEG MWs and with mixtures of PEG MWs. Preferential extraction of PEG from the cell lumens by toluene was shown to be an unacceptable approach for measuring PEG amounts in the CWs. Rates of diffusion of different PEG MWs into CWs were estimated by applying Fickian diffusion equations for plane and cylindrical surfaces. PEG Diffusion coefficients were in the order of 10-9 cm2/s for PEG MW 1000 and 10 -10 cm2/s for PEG 2000 and 4000 for both plane and cylindrical geometries. The high CW penetration rates suggested vacuum impregnation with PEG solutions as an efficient means of bulking wood.
Quantitative in-line color monitoring of polymer color concentrates in an extruder

A new monitoring system for polymer melt color during extrusion was developed based upon an inexpensive charge coupled device (CCD) spectrometer. A novel fiber optic cable circuit and use of a reference channel on the spectrometer permitted changes in light intensity to be accommodated. Four different mathematical corrections, the latter three of which were developed in this work for color interpretation, were employed: calibration factors, normalization, area ratio and “virtual white reference”. Three assessments were performed involving both off-line and in-line experiments. Assessment I involved only the first three mentioned corrections and led to the idea of a “virtual white reference”. Assessment II, monitoring of purposeful color contamination with using all four of the mathematical corrections, showed high sensitivity and precision (ΔE*ab < 0.1). Finally, Assessment III was a Plant Trial on a manufacturing extruder where the system demonstrated the same capabilities evident on the pilot scale.
Seismic upgrade with GFRP of RC columns containing lap spliced rebars in plastic hinge regions

Reinforced Concrete Columns detailed with poor lap splices and inadequate transverse confinement at the potential plastic hinge region near the footing or beam-column joint are found to be deficient under the strength and ductility demands imposed by severe earthquake. The current study is directed towards the evaluation of the effectiveness of Carbon FRP laminates in strengthening and repair of columns with poor splice and confinement details, under simulated earthquake loading. A total of 12 columns were constructed and tested. The variables studied in this program included, effect of the presence of lap splices, the effectiveness of CFRP, as well as effects of level of axial load, shape of column cross-section and confinement details. The CFRP retrofitting technique was found to be effective in enhancing the seismic resistance of the columns and resulted in more stable hysteresis curves with lower stiffness and strength degradations as compared to the un-retrofitted columns.
In vitro and in vivo investigations of mild hyperthermic modulation of palladium-bacteriopheophorbide (WST09)-mediated photodynamic therapy doses

Quantitative studies were performed to determine how mild hyperthermia (HT, 37--42°C) modulates photodynamic therapy (PDT) using a sub-cellular targeting photosensitizer aluminum phthalocyanine tetrasuflonate (AlPcS 4) and a vascular-targeting photosensitizer Pd-bacteriopheophorbide (WST09). The ultimate goal is to improve WST09-mediated PDT treatments of prostate cancer, which are currently under investigation at the University Health Network. Simultaneous HT enhanced WST09-mediated PDT of rat prostate endothelial cells in vitro (HER of 1.42--1.67 at 41--42°C). Using the PDT threshold dose as the in vivo metric, the first quantitative relationship between temperature and PDT threshold dose was determined. HT (40--42°C) reduced the PDT threshold dose by 48 +/- 10% and 27 +/- 9% for WST09 and AlPcS4 respectively. Finally, by coupling the in vivo data with a mathematical model of optical/thermal propagation in tissues, it was shown that adjuvant HT may be an effective strategy to modulate PDT treatment volumes or homogeneity of response.
Stacked FSMD: a new microarchitecture model for high-level synthesis

High-Level synthesis is a process that automates the transformation of an algorithmic description of a digital design into its physical implementation. With digital systems' ever increasing complexity in terms of transistor count and clock speed, it becomes necessary for a high-level synthesis tool to work at higher levels of abstraction in order to effectively cope with the design. Traditional high-level synthesis tools are unable to efficiently synthesize designs described in high-level abstract languages such as C or Java. This is because the Finite State Machine with Datapath model (FSMD), the underlying microarchitecture into which the synthesis tool transforms the design, is too simplistic. FSMD is unable to effectively capture high-level constructs such as procedure abstraction and memory allocation. This thesis makes two primary contributions: First, it proposes an extension of the FSMD model into a Stacked FSMD (SFSMD) model that supports procedure abstraction, and includes support for dynamic memory allocation. Secondly, it describes a behavioral level partitioning technique which leverages the SFSMD model to reduce power consumption.
Mechanisms underlying pulmonary hypertension in a rat model of bronchopulmonary dysplasia

Abnormalities of the pulmonary circulation have long been recognised to contribute to the morbidity and mortality of bronchopulmonary dysplasia, a common condition of extremely premature infants in which oxidant stress is believed to play a major role and for which there is presently no effective treatment. The hallmark of bronchopulmonary dysplasia is an arrest in alveolar and capillary development. A major circulatory manifestation of bronchopulmonary dysplasia is pulmonary hypertension due to vasoconstriction and increased muscularisation of pulmonary resistance vessels. Animal studies suggest that altered function and structure of the pulmonary circulation may adversely affect alveolar development. Newborn rats exposed to 60% O2 for 14 days develop pulmonary hypertension and parenchymal lung abnormalities that have close morphological similarities to human bronchopulmonary dysplasia. Previous interventional studies in this model have demonstrated that the development of pulmonary hypertension is dependent upon macrophage influx to the lung and up-regulation of endothelin-1, a potent vasoconstrictor peptide. In the studies reported herein, I demonstrated that increased macrophage influx is responsible for the increased reactive oxygen species formation and protein nitration in the lungs of newborn rats exposed to 60% O2 for 14 days. A consequence of oxidant stress is the formation of 8-isoprostane, a bioactive product of lipid peroxidation, which leads to the up-regulation of endothelin-1 production in smooth muscle cells, a major cellular source in the 60% O2-exposed lung. Treatment with a thromboxane A 2 receptor antagonist, but not a cyclooxygenase-2 inhibitor, abrogated these effects, suggesting that the thromboxane A2 receptor ligand causing increased endothelin-1 in the O2-exposed lung was not a cyclooxygenase-2 product, but rather an incidental ligand, such as 8-isoprostane. Finally, the platelet-derived growth factors ( -AA and -BB) and insulin-like growth factor-I are identified as mitogens, and endothelin-1 and 8-isoprostane as survival factors, of cultured pulmonary artery smooth muscle cells from infant rats, implicating them as direct mediators of pathological smooth muscle proliferation.
Figuring it out in the moment: Personal support workers' utilization of knowledge about person-centered care in dementia practice settings

The findings from this study enhance our understanding of how PSWs in Special Care Units make decisions about and act on knowledge related to person-centered care and how certain contextual, individual, and relational factors might influence these efforts. This understanding has practice and education implications for how we promote the best practice of PSWs in dementia care settings. The findings also have implications for theory and research which question how knowledge utilization is conceptualized and studied in relation to dementia care practice specifically, and health care practice overall. The purpose of this grounded theory study was to explore what influences Personal Support Workers (PSW) in institutional dementia care settings to utilize knowledge about person-centered care as a basis for their practice. Data were collected from 20 PSWs in Special Care Units across eight long-term care facilities through formal, semi-structured interviews and were simultaneously analyzed using the constant comparative method. The culmination of these investigative activities was a theory of the process by which PSWs utilize knowledge about person-centered care described as figuring it out in the moment. The theory of figuring it out in the moment suggests that PSWs in dementia care settings practice in a context of unpredictability, variability, and personal threat. Their use of knowledge about person-centered care in this context is dependent on the existence of certain individual and relational conditions. Individual conditions include PSWs' propensity for caring as well as their knowledge about Alzheimer Disease, their capacity to maintain composure in the face of anticipated or actual resident aggression, their flexibility and strength of perseverance, and their capacity to reframe practice challenges as opportunities for personal and professional growth. Relational conditions include collaborative peer relationships; opportunities to share and receive information about resident care from interdisciplinary team members; and acknowledgement and praise from team members, management, and residents' families. The process underlying the utilization of knowledge about person-centered care by PSWs is understood through the interrelationships amongst the various contextual, individual, and relational factors of influence and four separate but interconnected phases of PSW decision making and actions: the phases of Melding, Contextualizing, Trialing, and Appraising.
Ionic and pH homeostasis in metabolically active compartments

Maintenance of a stable hydrogen ion concentration ([H +]) is important in cells that have high metabolic rates, since they have elevated rates of hydrogen ion generation. One of such model systems are white blood cells, specifically polymorphonuclear leukocytes. These cells represent the very first line of protection against infections. In neutrophils during pathogen-induced oxygen consumption the cytosol concurrently experiences massive H+ generation. Failure to maintain a stable cytosolic pH would result in a decreased oxidative burst, inhibition of cellular migration and lower rates of phagocytosis. These protons can be eliminated either by consumption by buffering components and dismutation reactions or by extrusion across the plasma membrane. Efflux of protons can, in principle, be mediated through a H+ -conductive pathway that is expressed in neutrophils at high levels. The H+ conductance was postulated to be activated primarily by large depolarizations of the plasma membrane. I devised a new method to precisely measure the extent of depolarization of the plasma membrane resulting from neutrophil activation. Using soluble fluorescent probes and spectrofluorimetry, I managed to obtain reproducible measurements of membrane potential (E m = +58 ± 6 mV) in activated human neutrophils. The results suggest that H+-conductance contributes to the acid-base homeostasis during leukocyte activation. The pH regulation in leukocytes is critical also in the phagocytic vacuole. Using improved methods I have confirmed that phagosomal pH in neutrophils is neutral. I have established that the insertion of V-ATPases into the phagosomal membrane was reduced, and that passive proton (equivalent) permeability of the phagosomal membrane increased when the oxidase is active. These observations suggest that neutrophils rely mostly on bacteriostatic activity of reactive oxygen species rather than acidic hydrolazes. Finally, I have developed a novel method targeting a pH-sensitive fluorescent protein specifically to the peroxisomal lumen. This allowed me in detail re-examine the luminal pH of peroxisomes. Based on this non-invasive approach I have identified that peroxisomal pH was 6.9, resembling that of the cytosol. Further examination showed, that peroxisomes do not regulate their pH independently. Their large H+ (equivalents) permeability connects them with the buffer reservoir of the cytoplasm and with the homeostatic mechanisms that control cytosolic pH.
New bounds for bounded timestamps

A timestamp is a label that is attached to a process to provide temporal information about it relative to other processes. This information may change an unbounded number of times; however, despite this, bounded timestamps are still drawn from a finite set. This thesis provides new bounds on the size of this set for several models of concurrency: we consider the sequential model, in which processes do not execute concurrently; a new model with rounds in which a group of processes simultaneously get new labels; and a concurrent model, in which processes execute asynchronously. We also look at the relationships between these models.
Biochemical characterization of an RNA editing enzyme

The adenosine deaminases that act on RNA (ADARs) are a family of enzymes involved in A to I RNA editing. A to I RNA editing has been found to be involved in the synthesis of various neuronal proteins involved in signal transduction within the central nervous system including various glutamate receptor subunits. The pre-mRNA for the GluR-B glutamate receptor subunit has been found to be edited by the enzyme ADAR2. This thesis describes work that was undertaken to investigate A to I editing using a minimal system consisting of ADAR2 and model RNAs based on editing sites in the pre-mRNA for the GluR-B glutamate receptor subunit. The initial stages of this work involved establishing protein expression protocols and activity assays. Active recombinant ADAR2 was obtained from a yeast expression system and an assay based on nuclease P1 digestion was established that was suitable for detailed kinetic analyses. This system was then used to probe the mechanism of ADAR2. Gel mobility shift analysis revealed that two complexes formed on the RNA. The data from a detailed kinetic analysis revealed that the slower migrating complex in the gel mobility shift analysis (ESE) was responsible for ADAR2's activity. This data, in addition to data from crosslinking and deletion analyses, are consistent with ADAR2 functioning as a ternary complex consisting of two protein molecules on an RNA substrate (ESE) with the rate determining step of the reaction being formation of this complex from a pre-assembled protein-RNA complex (ES). Finally, one of the assays used to measure A to I editing was used to develop a template-directed RNA interference methodology based on inosine-specific cleavage. As a test case, the activity of the L-21G414 version of the Tetrahymena ribozyme was examined with this technique. The results were consistent with the extensive experimental data gathered about the ribozyme. This technique could thus be used to identify important guanosine resides in RNA structures and in RNA protein complexes.