VictorJuiz/thesis huggingface dataset:
Discontinuity in pore structure and its effect on mass transfer through hardened cement paste

Today, the mass transfer characteristics of concrete is measured by permeability testing or measured ionic diffusivity under saturated condition. However, saturation is not usually found in concrete in the field. The mass transfer characteristic of concrete is dependent on its pore structure and the boundary conditions. In this study, low pressure permeability test, high pressure permeability tests and water vapor transmission tests were conducted to evaluate the postulated effect of discontinuous pore structure in hardened cement paste (HCP) on two different mass transfer mechanisms: saturated water transfer and water vapor transfer. The low pressure permeability test is unable to determine permeability values below 1E-13 m/s, while the high pressure permeability test extends this lower limit to IE-16 m/s by using the modified high pressure permeameter. The pore structure of HCP was deemed to be discontinuous when "zero" flow was measured in the high pressure permeability test. However, water vapor transmission test shows significant mass transfer of water vapor through HCP even those having discontinuous pores according to high pressure permeability test results. Finally, the permeability models examined in this study give inaccurate estimates of permeability for HCP with discontinuous capillary porosity.
Testing of fibreoptic probes for measuring the size distribution of large bubbles

An experimental investigation was conducted to evaluate the potential use of fibreoptic probes for measuring size distributions of large bubbles entrained beneath breaking ocean waves. Specifically, the ability of Optoflow probes to measure the size distribution of large bubbles was investigated. The rise time of the signal pulses created when bubbles crossed the probe tip correlated with the bubble velocity. Therefore, bubble velocities and bubble sizes can be estimated using a single probe. The correlation between the rise time and the bubble velocity varied significantly between probes but was only a weak function of water type (i.e. fresh- or seawater) and probe orientation. Estimates of the bubble size distributions made using the fibreoptic probes and video image data were compared. Image measurements of void fraction were required to estimate probe measuring volume. Except at low velocities, there was good agreement between the size distribution measurements for large bubbles (d $\geq$ 1mm).
A pilot study on the use of sunlamps and tanning beds

Detailed data on the use of non-solar ultraviolet radiation (UVR) sources and the emissions from these devices are not currently available. We conducted a pilot study to describe the pattern of use of non-solar UV devices in young women in Metropolitan Toronto (Metro) between 1985-1995. The age adjusted prevalence of use in 1985-1995 by Metro women aged 20-44 was 20.7% (95% CI, 15.5-25.8). Tanning beds were the most popular tanning devices in Metro. The most commonly reported length of tanning sessions were 20 and 30 minutes. The percentage of ultraviolet B (UVB) to ultraviolet A, (UVB/UVA)%, of the tanning lamps in Metro varied from 0.7% to 8.5%. We found that it was feasible to gather data on the use of non-solar tanning devices by using our questionnaires. In addition, it was possible to estimate general non-solar UVA and UVB exposure from tanning sources where use was reported.
STM studies of laser-induced effects on rough silver films

Cold-deposited silver films, which are known to be self-affine were studied using STM and optical techniques. The fractal dimension of a 3000 A thick film deposited on sapphire was measured to be 2.23. Resistivity measurements show the deposited films to grow as islands, reaching a percolation threshold when the mass-thickness is approximately 100 A. The resistivity values of such films are approximately three orders of magnitude higher than the bulk value, indicating a highly porous, discontinuous film structure. The well-known plasmon absorbance in the visible region and the SERS activity of such film was also observed. The optical properties of the silver films were further studied by irradiating the film and simultaneously measuring the laser-induced tunneling current with an STM. The results demonstrate that by far the dominant response of the surface to laser irradiation is a uniform thermal expansion. The predicted localized optical response of self-affine films was not observed in this experiment.
Afterdischarge Threshold Reduction in the Kindling Model of Epilepsy

Afterdischarge threshold (ADT) changes were studied in the amygdala kindling model of epilepsy. Racine (1972a) reported that electrical stimulation lowers the ADT in amygdala-kindled rats, and that the presence of electrodes alone has no effect. More recently, however, Loscher et al. (1993, 1995) have produced data that suggest that ADT drop results from the presence of electrodes alone and that electrical stimulation may have no effect on ADTs. These conflicting views must be reconciled before meaningful research on threshold drop--and agents designed to prevent it--can be attempted. In Experiment 1, Racine's original finding that electrical stimulation lowered ADTs was replicated. In Experiment 2, Racine's procedures (Half-Split ADT determination, male rats) were applied at Loscher's time intervals. In Experiment 3, Loscher's original experiment was replicated with the addition of an unstimulated time-matched control group. Results make it clear that there are consistent changes in ADT following electrode implantation, and that these are independent of electrical stimulation--as Loscher suggested. When these are taken into account, however, the stimulation-induced changes reported by Racine can be seen. (Abstract shortened by UMI.)
Preschoolers' understanding of scale models, the role of imaginal transformation

Three-year-olds, but not 2.5-year-olds, successfully search for a large toy in a room after witnessing the hiding of an analogous smaller toy in a scale model of the room. Previous research (DeLoache, 1991, Experiment 2) suggests that the younger children's difficulty could be due to the lack of congruence between the perspectives from which the two spaces are viewed, and an inability to inhibit searching at a previously correct location. Two conditions, in which the views of the two spaces were congruent, were compared to two conditions in which the views were incongruent. The results indicate that there was no effect of perspective congruity on successfully searching in the room. A significant proportion of both 2.5- and 3.0-year olds' errors involved searching at the location that was correct on the preceding trial. The results are discussed in terms of competing response systems.
The incidence and mortality rates of, and the referral and treatment patterns for, soft tissue sarcomas of the limb in Ontario, 1964-1993

The purpose was to document trends of incidence and mortality rates of, and the referral and treatment patterns for, soft tissue sarcomas of the limb in Ontario, 1964-93. A total of 3557 incident cases of soft tissue sarcoma of the extremity in the OCR were investigated. Case definitions impacted on the populations derived and the rates generated from the populations. Two different case definitions provided different age-adjusted incidence rates over time; and the age-adjusted all-cause mortality rates trended downward over time for both case definitions. A clustering of increased incidence and mortality rates was observed in northern Ontario. The most common histologic diagnoses were liposarcoma and malignant fibrous histiocytoma. Approximately 55 to 60% of the patients had contact with a tertiary care center which trended upward from 1964-93. The rates of amputation decreased over time and the rate of usage of radiotherapy increased.
Multimedia workstation architecture with ATM interconnect

This thesis describes a multimedia workstation architecture, which uses an ATM switch rather than a traditional system bus, for connecting both multimedia and non-multimedia peripherals. This architecture is intended to eliminate the performance bottlenecks which are present in a typical bus-based workstation during transfers of high bandwidth information among the internal workstation components and between the workstation and the external network. The thesis discusses other recently developed multimedia workstation architectures, their advantages and shortcoming. The detailed structure of the proposed workstation architecture, including the CPU, memory, video display, disk, and ATM switch, is discussed. To offer a performance comparison between the proposed architecture and a generic bus-based system, a computer simulation was created to show the delays for both types of interconnect when subject to typical multimedia data streams. The simulation shows that the performance of the ATM workstation can be up to nine times better compared to the bus-based workstation for typical high bandwidth multimedia loads. However, the performance of the proposed ATM architecture is highly dependent on the number and the pattern of connections among workstation peripherals through the ATM switch.
Oxygen pathways on unpromoted and chlorine inhibited silver epoxidation catalysts

Oxygen pathways in ethylene epoxidation over unpromoted and chlorine inhibited silver catalysts were studied between 190$\sp\circ$C and 290$\sp\circ$C. Steady state dynamic isotope tracing $(\rm\sp{16}O\sb2 \to {\sp{18}O\sb2})$ was the primary technique. Results from the unpromoted catalysts showed three kinetically distinguishable oxygen pools on silver during the steady state reaction: two forms of active surface oxygen, one for each reaction pathway, and a reservoir of subsurface oxygen. Chlorine increases both the amount of subsurface oxygen in silver and the rate of supply from the subsurface to the surface. The increased oxygen supply rates correlate well with increased ethylene oxide selectivity on the chlorine inhibited catalysts. Steady state $\rm C\sp{18}O\sb2$ and $\rm C\sb2H\sb4\sp{16}O$ exchange experiments were performed to characterize the oxygen scrambling behaviour of the products under the same conditions as the previous dynamic isotope tracing experiments. Implications of the oxygen exchange results are discussed in relation to the dynamic isotope tracing experiments.
Interrelationships among physical symptom distress, psychological distress, and fatigue in women with breast cancer undergoing radiation therapy

This secondary analysis was designed to examine how physical symptom distress, psychological distress, age, and tamoxifen affected level of fatigue in 101 women with breast cancer undergoing the last week of radiation treatment. All women experienced fatigue. Results of path analyses indicated that (a) psychological distress has a direct effect on fatigue, (b) physical symptom distress has a direct effect on fatigue, as well as having an indirect effect through its effect on psychological distress, and (c) age has an indirect effect on fatigue through its negative impact on psychological distress. Physical symptom distress had the greatest causal effect on the level of fatigue. Given the limitations indicated, this study suggests that nursing interventions must be directed at identifying the effective strategies in reducing physical symptoms in order to prevent or reduce fatigue.
Design of photoregulated ribonuclease

Bovine pancreatic ribonuclease A (RNAse A) is a well defined enzyme that has been used as a test protein in the study of a wide variety of chemical and physical methods applied to protein chemistry. The design of a photoregulated RNAse is a test case for rational design of a photoregulated enzyme. If one could design photoregulated biomolecules, then a variety of cellular processes could be studied using light as a tool. A photoisomerizable amino acid residue phenylazo-phenylalanine (PAP) was synthesized and incorporated into S-peptide analogues using solid phase peptide synthesis techniques. Noncovalent reassociation of S-peptide analogues bearing PAP residues at positions 4, 8 and 11 with S-protein was examined. PAP-4 and PAP-11 analogues were able to reconstitute ribonuclease activity. Photoisomerization of the PAP-4 peptide modulated enzyme activity.
Influence of menstrual cycle phase and oral contraceptive use during compensable and uncompensable heat strain

The purpose of this study was to determine the influence of menstrual cycle phase and oral contraceptive use during compensable and uncompensable heat strain. Eighteen women (18-35 yr), who differed only with respect to oral contraceptive use (n = 9) or non-use (n = 9), performed light intermittent exercise at 40$\sp\circ$C, 30% relative humidity while wearing either Canadian Forces combat clothing or NBC protective clothing. Thermoregulatory responses in each clothing configuration were compared during the early follicular (EF, days 2-5), late follicular (LF, days 9-12), and mid luteal (ML, days 19-22) phases of the menstrual cycle. Rectal temperature was elevated in ML compared with EF among the non-users, but not the users in both clothing configurations. There were no phase-related or group-related differences in any of the other indices of heat strain. Tolerance times were similar between the two groups in all three phases during the compensable heat strain trials. During uncompensable heat strain, tolerance times were significantly longer during EF (128.1 $\pm$ 13.4 min) compared with ML (107.4 $\pm$ 8.6 min) for the non-users, indicating that these women are at a thermoregulatory advantage during the EF phase of their menstrual cycle. For the users, tolerance times were similar in all three phases and did not differ from those of the non-users during uncompensable heat strain. Our results demonstrate that oral contraceptive use appears to make the thermoregulatory responses to heat strain more uniform over the course of the menstrual cycle.
Cloning and sequencing of genes that control lung branching morphogenesis

The mammalian lung develops from the primitive foregut. The primordium of the respiratory system appears in the developing rat around 11 to 12 days (term = 22 days) with the formation of two buds which undergo dichotomous branching. Although transcription (thyroid transcription factor-1, hepatocyte nuclear factor) and growth factors (platelet-derived growth factor, keratinocyte growth factor and epidermal growth factor) are implicated in regulating lung branching morphogenesis, the exact molecular signals guiding embryonic lung development remain largely unknown. In the present study, we identified genes that are specifically expressed in the embryonic (day 13), but not late fetal (day 21), rat lung using mRNA differential display. After reverse transcription (RT) and polymerase chain reaction (PCR), eight cDNA fragments were shown to be exclusively expressed at day 13 of gestation. Six of them were successfully reamplified, cloned and sequenced. Eleven distinct sequences were obtained, since larger cDNA bands contained more than one DNA species. RT-PCR using cDNA specific primers demonstrated that five of the genes showed a developmental stage-specific expression, i.e. expressed at 12-13 days of gestation but not later during fetal lung development. In addition, mRNA expression of these genes in day 13 fetal lung was greater when compared to other day-13 fetal foregut-derived organs, such as intestine and liver. Functional analysis revealed that an antisense oligonucleotide targeted to gene 4.6 completely blocked branching of embryonic rat lung in vitro. Antisense inhibition of three other genes partially inhibited lung branching. To further identify these genes, a day-13 fetal rat lung cDNA library has been constructed. Localization of the genes will be examined by in situ hybridization. Putative function of the genes in branching morphogenesis will be investigated using transgenic approaches.
Coating removal from aluminum using wheat starch blast cleaning

Wheat starch blast cleaning is increasingly used to remove organic coatings from aircraft. The aim of this work was to maximize the productivity of the process by gaining a better understanding of the mechanism of coating removal, and by studying how various process parameters affect it. The impact sites left by individual wheat starch particles on the coating were examined, the size and shape of the particles were studied, and particle velocities were measured. The relationship between particle size and velocity was also explored using a mathematical model. Finally, the results of these experiments were correlated with paint removal rates, which were found to depend strongly on nozzle angle and particle velocity, but also depended on particle size and shape. The best paint removal rates were achieved at a nozzle angle of 45$\sp\circ,$ and it was shown that the topcoat was removed in a cumulative fashion by chipping (ductile erosion). Lastly, a selective stripping "window" was observed for the coating system studied, i.e. it was possible to remove the topcoat while leaving the underlying primer intact.
Abundance, Diversity, and Nesting of Ants (Hymenoptera, formicidae) in White Pine Forests of Ontario

This study investigated the relationship between the abundance and diversity of ant species and different spatial habitats within Ontario. Ant faunae in three regions were compared in mature and old growth white pine, and non-white pine forests. Fifteen ant species, from seven genera were captured. Aphaenogaster picea (p $<$ 0.03), Camponotus pennsylvanicus (p $<$ 0.03) and Myrmica detritinodis (p = 0.006) occurred in the Algonquin region more than the other two regions. Myrmica alaskensis occurred in the NW region more than the other two regions (p = 0.001). An intensive study of the NE region revealed thirteen ant species from seven genera. Only Stenamma brevicorne exhibited a difference (p $<$ 0.001) between the four selected forest types. Ant species were found in dead wood, moss, soil and duff. Location within Ontario, tree species composition and successional stage of a forest, and microhabitat all need to be conserved in order to maintain ant abundance and diversity in Ontario.
Comparison of polymorphic CYP2D6, CYP2C19 and CYP2A6 in Canadian Native Indian, Caucasian and Chinese populations

A number of human cytochrome P450 enzymes are polymorphically expressed. This results in inter-individual differences in the ability to metabolize substrate drugs. More importantly, they exhibit significant inter-ethnic differences in the frequencies of mutant alleles and frequencies of the poor metabolizer genotype and phenotype. Although P450 enzymes have been studied extensively in Caucasian and Asian populations, very little is known about their genetic variation in Canadian Native Indians. Mitochondrial DNA studies have shown that Canadian Native Indians are descendants of north Asian populations which crossed the Bering Strait between 13,000 and 30,000 years ago. This agrees with previous evidence gathered from linguistic, dental and morphological studies. We have therefore hypothesized that Canadian Native Indians will resemble Asians, and differ from Caucasians, with respect to the frequencies of CYP2D6, CYP2C19 and CYP2A6 mutant alleles. We have studied the screened 159 Canadian Native Indian subjects for CYP2C19 (CYP2C19*2 and CYP2C19*3) and CYP2A6 (CYP2A6*2 and CYP2A6*3). These data have been analyzed and compared to Caucasian and Asian data previously reported in literature and data from our own laboratory. Canadian Native Indians were significantly different from both Caucasian and Asian populations with respect to the genotype patterns of both CYP2C19 and CYP2A6. This study was unique in that it investigated both the CYP2C19 and CYP2A6 polymorphisms in one population, thereby allowing us to determine whether there was any association between the CYP2C19 and CYP2A6 genotypes. Analysis of Canadian Native Indians suggests that there is an association between the presence of the CYP2C19 and CYP2A6 mutant alleles such that the co-occurrence of these two alleles is higher than would be predicted based on their frequencies in this population. (Abstract shortened by UMI.)
A requirement for the receptor tyrosine kinase, Flk1, in hematopoiesis and vasculogenesis

The Flk1 receptor tyrosine kinase is expressed on early hematopoietic and endothelial cells in the mouse embryo. Flk1$\sp{-/-}$ embryos die at the mid-somite stage, lacking both endothelial and hematopoietic cells. To further investigate the role of Flk1 signalling in vasculogenesis and hematopoiesis, the developmental potential of Flk1$\sp{-/-}$ embryonic stem cells in chimeras was examined. This analysis demonstrated a cell autonomous requirement for Flk1 in endotehlidal development. In addition, Flk1$\sp{-/-}$ cells did not contribute to primitive hematopoiesis in chimeric yolk sacs, or definitive hematopoiesis in adult chimeras and chimeric fetal livers. Furthermore, Flk1$\sp{-/-}$ were unable to reach the right location to form the blood islands, suggesting that Flk1 is involved in the movement of cells from the posterior primitive streak to the yolk sac.
Implementation of a distributed interactive simulation interface in a Sea King Flight Simulator

The Distributed Interactive Simulation (DIS) Protocol is used to implement a network simulation between a Sea King Simulator and a Canadian Patrol Frigate Landing Safety Officer Simulator. Due to entity contact which was made once the helicopter landed on the deck of the ship, extensive use of smoothing algorithms was required. An investigation into the optimal values for the dead reckoning thresholds and the number of smoothing steps was conducted. The results showed that smoothness of the simulation could be maintained with an acceptable trajectory error.
The potential for thread-level data speculation in tightly coupled multiprocessors

To fully exploit the potential of single-chip multiprocessors, we must find a way to parallelize non-numeric applications. However, compilers have had little success in parallelizing non-numeric codes due to their complex data access patterns. This thesis explores the potential for using thread-level data speculation (TLDS) to overcome this limitation by allowing the compiler to view parallelization solely as a cost/benefit tradeoff, rather than something which may violate program correctness. Experimental results demonstrate that TLDS can offer significant program speedups. We also demonstrate that through modest hardware extensions, a standard single-chip multi-processor could support TLDS by augmenting the cache coherence scheme to detect dependence violations, and by using the primary data caches to buffer speculative state. We quantify the impact of this implementation on performance, and we also evaluate the compiler support necessary to exploit TLDS.
Development of dopamine receptor-expressing adenoviral vectors

DNA can be efficiently transferred into cells, both in vitro and in vivo, using viral mediated gene transfer. The major objective of this project was to develop E1-deleted recombinant adenoviruses expressing the D2 and D4 dopamine receptors. Isolated recombinant adenoviruses were characterized, in vitro, using saturation binding analysis, competition binding analysis and functional analysis which measures inhibition of forskolin-stimulated cAMP. CHO-K1, COS-7, HeLa, SK-N-MC, GH4-C1 and LTK$\sp-$ cell lines were used for the in vitro characterization. Transgenes were expressed at high levels in several cell lines. Pharmacological characterization verified that the correct dopamine receptors were highly expressed and functional. A second objective was to improve viral mediated gene transfer by creating a pseudovirus, deleted of all viral genes, capable of transferring foreign genes into cells. Using adenovirus as a helper virus an SV40 based pseudovirus expressing the luciferase reporter gene was created. Strategies and preliminary data for an adenoviral based pseudovirus are also presented.