Graphical information has become a critical method for portraying information for education, work and personal tasks and decisions. Unfortunately there are currently limited means of providing this information to individuals who are blind or visually impaired: alternate text is frequently missing, and accessible tactile diagrams tend to be time consuming to make and require expertise in order for them to be interpretable (which may be costly to the user and/or impossible to get). The aim of this project is to provide an accessible system to automatically generate tactile graphics for those who need to interpret information contained in visual images. Previous automatic conversion methods have not been especially successful and are not used in normal practice, possibly because they have not taken advantage of current advances in the field of image processing. In the preliminary work, we systematically look at the myriad of image segmentation methods that exist as part of the conversion process. For those techniques, previous researchers have often compared the results to the “gold standard” of human segmentation to evaluate their success. However, there are important difference between this “gold standard” and what is needed for tactile graphics. Key steps by professionals who create tactile diagrams are simplification so that the information is manageable to extract through the tactile sense, elimination of perspective as it is difficult to interpret tactually, and possible spreading of information across multiple diagrams. Planned work is to examine more closely the underlying themes to the myriad of algorithm are relevant for tactile diagrams. Future work, will also involve taking the initially segmented image, simplifying it further by removing “unimportant” detail so that it is manageable by the tactile system and removing perspective based on geometric information found in the image.

Bacteria are key players in the processes that govern fate and transport of contaminants. Previous assessment showed that the Arthrobacter oxydans (A.oxydans) G968 strain has a lower ability to tolerate U(VI) toxicity in bicarbonate-free media compared to other isolate A.oxydans G975. The study experimentally investigated several parameters such as the potential of bicarbonate to accelerate U(VI) release from autunite mineral in the presence of a less U(VI) tolerant bacterial strain, in the conditions mimicking Hanford Site subsurface environments. Results showed that despite morphological differences between the two bacterial strains, A.oxydans G968 and G975, they are able to dissolute uranium at the same capacity. The effect of both bacterial strands on autunite dissolution reduces as the concentration of bicarbonate increases. AFM and viability studies showed that samples containing bicarbonate are able to acclimate and withstand uranium toxicity. This study provides a better understanding of the bacterial role in polyphosphate remediation technology and interactions between meta-autunite and microbes.

The goal of this study was to compare the morphological and hemodynamic characteristics of normal and remodeled vascular networks in the mouse gracilis muscle. To this end, previously developed models to assess flows and vascular branching were used to assess the normal and remodeled microcirculatory networks. The analysis revealed that the average individual vessel flow rates for vessels of similar caliber and total volumetric flow rates in the networks do not change for vessels of the same caliber after remodeling. Connectivity changes and average diameters primarily change in the larger arterioles after remodeling. A few correlations could be made between architectural and flow properties, however, further modifications in the analysis methods can make future correlations more effective. In order to improve the analysis a parameter sensitivity analysis tool (PSAT) was developed. The PSAT is helpful in teasing apart the individual effects of morphological parameters such as vessel connectivity, vessel diameters, and vessel lengths. In future, another important component that allows the investigator to exclusively alter vessel quantities for all the orders can be added to improve the PSAT.

Coronary artery disease (CAD) is a common cause of sudden cardiac death. Much of the disease is not completely understood, which makes treatment and prevention difficult. Many researchers are using technology, such as advanced imaging techniques and finite element analysis, to better understand the disease. While there is much progress being made to look at the analysis of actual excised diseased arteries, there is still not a standardized model to predict the future of any one lesion. The purpose of this study is to explore the possibility of creating a standardized model to predict the mechanical stability of the fibrous cap due to lipid content in atherosclerotic lesions.

Bacteria are among the most abundant microorganisms on earth, and can be found in essentially every environment. When a clean surface is exposed to media containing planktonic bacteria, the bacterial cells will attach to the surface and aggregate to form what is known as a biofilm. Biofilms have been shown to negatively affect many industries including medical, industrial, and food science applications. While biofilms have been well characterized from a microbiology perspective, there has been much less research from a materials science standpoint. It is hypothesized that the material properties of the substratum (such as the micro-structure) have a significant impact on biofilm growth. To research this hypothesis, protocol was established in order to produce, analyze, and study biofilms in a static exposure system. Though simple, the static bioreactor was proved to be adequate for inducing microbial attachment to processed samples. Methodologies for analyzing the established biofilms were presented, and an experimental procedure was proposed that enables the correlation of material properties to microbial growth on the substratum. The experimental procedure utilized Design of Experiments in a three factor, two level study that identified the interaction of Material Composition, Surface Conditions, and the Effect of Welding on microbial growth. In a trial iteration of the experiment, samples of 303 and 304 Stainless Steel were mounted in Bakelite and processed. Some samples were sanded to 600 grit sand paper, while others were polished to 1µm. The samples were exposed to biologically active natural water and imaged with scanning electron microscopy. Preliminary results were presented, and limitations of the study were identified.

Particle Image Velocimetry (PIV) is an optical technique used for the visualization of fluid flow. PIV can be combined with other techniques to enhance the analysis of fluid flow. A novel far-field plasmonic resonance enhanced nanoparticle-seeded Particle Image Velocimetry (nPIV) has been demonstrated to measure the velocity in a micro channel. Chemically synthesized silver nanoparticles have been used to seed the flow. By using Discrete Dipole Approximation (DDA), plasmonic resonance enhanced light scattering has been calculated for spherical silver nanoparticles with diameters ranging from 15 nm to 200 nm in two media: water and air. The diffraction-limited plasmonic resonance enhanced images of silver nanoparticles at different diameters have been recorded. By using standard PIV techniques, the velocity within the micro channel has been determined from the images collected. The plasmonic resonance effects of nanoparticles from different media as compared to metal nanoparticles are also examined. Localized Surface Plasmon Resonance (LSPR) effects by naturally occurring Chinese yam particles are observed and quantified. Chinese yam particles are found by an atomic force microscope and a high-speed optical dark-field microscope. The particles with diameters greater than 200 nm are found to contribute most to UV-Vis absorption. LSPR effects of silver nanoparticles by the Chinese yam particles lead to the red shift of the extinction peaks of the silver nanoparticles. The wavelength shifts are quantitatively predicted based on DDA of the LSPR effects, which are sensitive to the local dielectric constant changed by the Chinese yam particles. This finding may open a new avenue to detect the biological sub-micron particles or virus in solution. PIV gives a new perspective on fluid flow that is otherwise difficult to see. An application of PIV studying the flagella movement of Giardia Lamblis trophozoites is examined. Standard PIV techniques are employed using a combination of high-contrast CytoViva ® imaging system to capture the images at high speeds and the Insight 3G software to measure the speed and direction of fluid motion generated by the microscale flagella. The PIV images illustrate how the flagella of the Giardia interact with each other and how they move in their environment.

Eight naturally deposited beef cow manure patties were sampled during summer (July 19 to August 9, 2010), fall (October 26 to November 19, 2010), winter (January 14 to February 18, 2011), and spring (May 5-27, 2011) to determine whether hypothesized seasonal differences existed in the initial concentrations and decay rates of Escherichia coli (E. coli) and bovine Bacteroidetes (BoBac). E. coli concentrations were estimated as culturable colony forming units (CFU) and with a quantitative polymerase chain reaction (qPCR) assay targeting the 23S ribosomal gene. BoBac was quantified with a qPCR assay targeting a 16S ribosomal gene sequence associated with cattle manure. Initial concentrations for culturable E. coli varied several orders of magnitude during each season, but were significantly lower when the animals grazed fresh forage (3.6 and 4.3 log10CFU/g-dry-manure in fall and spring, respectively) versus receiving hay and grain because of dormant pastures (6.4 log10CFU/g-dry-manure in winter). Average initial E. coli 23S gene abundance was also highly variable but lower in the spring and fall (7.1 and 8.5 log10copies/g-dry-manure) than in the winter (9.4 log10copies/g-dry-manure). Average initial BoBac 16S gene abundance was much less variable but again lower during grazing (9.9 log10copies/g-dry-manure in both spring and fall) versus during supplemental feeding (11.0 and 11.2 log10copies/g-dry-manure in summer and winter, respectively). Linear regressions of aggregated log transformed concentration data were used to calculate seasonal decay rate coefficients. The decay rate for culturable E. coli was highest in the winter (-0.094 log10CFU/g-dry-manure/day) and significantly lower in the fall and spring (-0.028 and +0.018 log10CFU/g-dry-manure/day, respectively). The same was true for E. coli 23S gene abundance (-0.086, -0.026, and +0.023 log10copies/g-dry-manure/day in winter, fall, and spring, respectively). The decay rates were far higher for BoBac 16S gene abundance which had an opposite seasonal trend, being much higher in the summer (-0.33 log10copies/g-dry-manure/day) than in the winter (-0.10 log10copies/g-dry-manure/day). The fact that initial bacterial concentrations and decay rates vary seasonally should be considered when modeling the fate and transport of the regulatory fecal pollution indicator E. coli and the fecal pollution source tracking BoBac gene sequence.

<p>Chronic kidney disease (CKD) has an annual mortality rate of 22% and can cause secondary complications including hypertension, anemia, secondary hyperparathyroidism, and malnutrition. Currently, clinical diagnosis and evaluation of CKD involves blood and urine testing and biopsy. MRI is not currently used to image CKD, but there is an interest in developing MRI techniques to test kidney function. Usually, renal functional MRI refers to single images reflecting tissue oxygenation. Using time series information may offer additional information about changes in kidneys as a result of disease. In this thesis, blood oxygen level-dependent (BOLD) MRI and diffusion weighted imaging (DWI) were used to investigate the effects of breath holding and water loading on kidneys. First, BOLD MRI was used to measure effects of breath holding on BOLD signal intensity. DWI and fractal analysis were used to measure changes in diffusion, perfusion and microcirculation shortly after water loading. Breath holding results showed no effect on temporal BOLD signal intensity in young, healthy subjects. A significant decrease in signal intensity was measured in the kidney of a single subject with impaired renal function. Although the renal BOLD signal was found to have fractal characteristics, no changes were measured using this technique between pre- and post-water loading scans during the time period examined. Because the signal appears to behave fractally, this technique may be a good candidate for similar kidney function studies in the future. DWI also remained unchanged as a result of water loading during the post-water loading time period examined.</p> / Master of Applied Science (MASc)

Vibrotactile feedback offers a unique opportunity to augment or reconstruct impaired tactile sensations, whether that be in the form of enhancing prosthetics or specialized protective clothing. Important information about temperature and object slippage serve to endanger the human operator or equipment. This thesis presents three experiments which investigate amplitude modulated vibrotactile signals as a scalar dimension of roughness, the effect those signals and their locations (finger pad, forearm, bicep) have on the performance of two tasks: the sensing of temperatures simulated by vibrotactile signals and gripping an object of simulated surface texture. The results show task performance increase when the feedback and site of action are co-located for sensory tasks and decrease for manipulatory tasks.

Obesity is associated with increased sympathoactivation that elevates arterial pressure. However, the mechanism linking sympathetic activation to arterial pressure is unclear. Specifically, it has never been demonstrated unequivocally that sympathetically mediated vasoconstriction is increased in obesity. This project tested the hypothesis that sympathetic vascular tone is increased in obese normotensive and hypertensive subjects. The effect of weight loss on sympathetic vascular tone was also assessed. Sympathetic vascular tone was assessed as forearm vasodilatation to intra-arterial phentolamine (?1/2-adrenergic receptor antagonist). Pharmacological responses were correlated with skeletal muscle sympathetic nerve activity (mSNA). Obese subjects with and without hypertension had increased mSNA. However, the vasodilatator response to phentolamine was not augmented in obese normotensive and hypertensive subjects versus lean controls. Additionally, weight loss did not alter phentolamine's vasodilatator response, despite reducing mSNA and arterial pressure in obese groups. These results indicate that sympathetic vascular tone is not increased in obesity despite higher mSNA. These studies also assessed forearm resistance vessel function using intra-arterial nitroprusside (nitric oxide donor) and isoproterenol (?2-adrenergic receptor agonist). The effects of weight loss on these responses were studied in the obese groups. The response to both vasodilators was blunted, but only in obese hypertensive subjects. Weight loss normalized the response to nitroprusside but not to isoproterenol. This result suggests that obesity-related hypertension is associated with vascular smooth muscle dysfunction, which can be improved by weight loss. Blunted vasodilatation to isoproterenol suggests an abnormality on ?2-adrenergic receptor-dependent mechanisms that may or may not depend on the endothelium. Also, mental stress-induced forearm vasodilatation was blunted in obese normotensive subjects, which was not normalized by weight loss. In conclusion, increased sympathetic nerve activity does not augment forearm sympathetic vascular tone. This dissociation could be due to opposing local factors (e.g. insulin, leptin) or to a different target of limb sympathoactivation (e.g. adipocytes vs. vascular). Sympathetic drive to tissues other than the peripheral circulation may play a more important role in arterial pressure elevation in obesity, either directly or indirectly.