title: Capacitance Sensing for Robotic Arm Collision Avoidance

contributor:
Bone, Gary M.
Mechanical Engineering

subject:
robot
collision avoidance
collision
robot arm
capacity sensing

abstract: Existing robotic arms have limited or no ability to avoid collisions with their environment due mainly to the lack of a suitable sensing system. A collision avoidance capability should be incorporated into every robot so that injuries to people and damage to equipment from collisions are prevented. Important applications that could benefit from robot collision avoidance include: manufacturing, robot-assisted surgery, robotic handling of hazardous waste, and personal robots. Creating a full-coverage, fast, reliable and cost effective sensing system for sensor-based robotic arm collision avoidance is a challenging problem. Capacitive sensors were selected based on their promising potential. Capacitive sensors have the limitations of nonlinearity and being influenced by the environment. In this thesis, their sensing behaviour, and solutions to these limitations, were investigated. A forward model predicts the capacitance for a given electrode geometry. The conventional method, Method of Moments (MoM) and Finite Element Method (FEM) were investigated and compared. The MoM demonstrated that the fringing electric field ignored by the conventional forward model is significant for the robotic arm application due to the relatively large ratio of electrode gap to electrode area. Two forward modeling cases were simulated by writing macro code for a commercial FEM package. The first consisted of two parallel cylindrical robotic arms. The second consisted of two cylindrical shell electrodes wrapped around a pair of robot links that rotated relative to each other. The results for this case were compared with experimental results. The FEM results were a poor predictor of the experimental results. The failure of the FEM model to include the true environmental conditions (e.g. air humidity and surrounding electric fields) is the most likely cause of its inaccuracy. An inverse capacitance model outputs the electrode geometry for a given capacitance. In this research the desired geometric output was the seven robot link pose variables, (x, y, z, q_x, q_y, q_z, q_0), describing the position and the orientation of the link of a robotic arm. A Cerebellar Model Articulation Controller (CMAC) neural network was chosen for the inverse modeling based its ability to model nonlinear behaviour and its efficiency. One CMAC network was trained for each pose variable. The sensor was built using capacitance sensing circuit and a multiplexor board with the potential for 16 by 16 electrode combinations. Note that an n by n combination produces n^2 separate capacitance values. For the inverse modeling experiments, four aluminum foil electrodes were mounted on a CRS-F3 robotic arm and four aluminum foil electrodes were placed on a wooden box used to simulate a second stationary robotic arm. A pair of reference electrodes was mounted on the back of the CRS-F3 arm. This reference measurement was used to normalize the measured capacitances in order to minimize environmental effects. The normalized capacitance data were used to train and test the CMAC neural networks. The CMAC learning factors were dynamically changed to reduce the training errors. A new fuzzy logic approach was developed that allowed the range of the CMAC input data to be increased without significantly increasing the training error. After evaluating eleven combinations of electrodes, it was determined that only the 3 by 3 and 4 by 4 combinations converged with small training errors. Three methods were used to analyze the CMAC testing errors: comparison plots, error plots and error metrics. Over a 15 cm range, pose variable y had maximum absolute errors of 2.1 mm for the 4 by 4 electrode combination and 7.2 mm for the 3 by 3 electrode combination. For the 4 by 4 combination the maximum relative errors were less than 3% for the x, y, and z variables, and less than 15% for the quaternion variables. For the 3 by 3 combination, these values increased to 13% and 20%, respectively. The larger relative errors for the quaternion variables were due to their smaller ranges of variation. Using the same hardware, a simple collision avoidance system was implemented using one pair of electrodes to detect the potential collision between a robotic arm moving in the vertical plane and a second stationary robot. The robot was shown to successfully avoid the potential collision and then continue its motion.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Design and Resource Allocation for Solar-Powered ESS Mesh Networks

title: Solar-Powered ESS Mesh Networks

contributor:
Todd, Terence
Szymanski, Ted
Electrical and Computer Engineering

subject:
design
resource
solar-power
ESS mesh

abstract: In this thesis we consider design methodology and resource allocation for IEEE 802.11 ESS mesh networks. In such networks, solar powered access points can be used to significantly reduce the installation cost of outdoor WLAN hotzones. SolarMESH is a network of this kind and is currently in its second year of an operational deployment. In SolarMESH, the cost of the solar panel/battery can be a significant fraction of the total, and therefore reducing AP power consumption is very important. Unfortunately, access point power saving is not currently supported under IEEE 802.11, but this would be very useful in future versions of the standard. A design methodology is presented for sustainable solar powered ESS mesh networks, assuming a power saving version of IEEE 802.11. First, a load profile for each network node is determined. The load profile is a time function which represents the average workload for which the node in question is designed. For a given geographic location, public meteorological data is then used together with the averaged offered capacity profile to provision each node subject to a target outage probability. The design is statistical since future load conditions and solar insolation may not exactly match that for which the node was designed. For this reason, a control algorithm is introduced which attempts to maintain outage-free operation of the node by introducing a capacity deficit under certain conditions. Results are presented showing that significant resource reductions are possible using the proposed resource allocation methodology. The results also give a strong motivation for including access point power saving in outdoor ESS mesh networks.

abstract: Thesis

abstract: Master of Science (MS)


title: The On-water Instrumentation of a Sprint Canoe Paddle

contributor:
Tullis, Stephen
Mechanical Engineering

subject:
sprint canoe
instrumentation
canoe blade
canoe stroke
hydrodynamics
sport measurement
blade force
paddle orientation

abstract:
A fully instrumented on-water sprint canoe system was designed, built, and tested. The system consists of: one 6-axis load cell in the paddle shaft at the blade, one inertial measuring unit (IMU) on the paddle, one IMU on the boat, and one GPS unit on the canoe boat. These sensors communicated wirelessly to a laptop where the data was processed and displayed in real-time. The sensors were rigorously tested and well-measured in their satisfactory accuracy. The system can provide a full decomposition of the blade water force into propulsive (forward/aft), side, and vertical forces. Previous systems for canoe have been extremely simple and rudimentary. There has been more effort in the rowing and kayak systems but they still failed to capture a full force profile.

On-water tests with national-level athletes examined a wide variety of sprint canoe strokes at different paces, power inputs, rates, and stroke lengths. The measurement system could clearly see the differences in force profiles between the stroke sets. A number of efficiency measures were developed using the available data. Instantaneous and integral in-stroke force ratios were developed based on the blade's propulsive force to total force proportion. Derived stroke averaged efficiencies also provided more information. These produced measurements of energy/impulse input to the boat's propulsion output. Differences in such efficiencies could be clearly seen in the various collected stroke sets.

This system will be highly useful to high performance athletes and coaches for modifying athlete technique. It has potential for improving equipment design and matching athletes to optimal blade styles. More academically, it can assist biomechanical assessments of sprint canoe and numerical flow studies around blades.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: A measurement system for a sprint canoe paddle was created that can evaluate an athlete's stroke performance during race-like conditions. This system was tested using national-level athletes in a true on-water setting. By measuring the force and orientation of the athlete's strokes, the system was able to clearly distinguish the performance of various stroke techniques. Analysis of the force profiles and the derivation of stroke efficiencies provided additional performance indicators. This is the first system to achieve this amount of measurement detail of any rowing or paddling sport. This fully instrumented paddle system is ready to be used as a coaching tool to improve athlete performance. It can also be used as an academic tool for paddle blade study.


title: Dynamic Power Saving and Load Balancing for Solar Powered WLAN Infrastructure

title: Power Saving and Load Balancing for Solar WLAN

contributor:
Todd, Terence
Electrical and Computer Engineering

subject:
power saving
load balance
solar power
WLAN
infrastructure
power
load

abstract: The IEEE 802.11 standard has been widely adopted as a Wireless LAN (WLAN) technology. This widespread proliferation of the technology has lead to an increase in the number of users taking advantage of so-called "hot-spots" which leads to an increased demand on bandwidth provided by Access Points (APs) in the hot-spot. The logical solution is to deploy more overlapping access points in the same coverage area, thus increasing the capacity of the system by providing load balancing services. However, when a hot-spot is located in an outdoor environment, it becomes difficult to provide the AP with power which is traditionally carried over wired links thus causing the service provider to incur additional costs, not to mention the impossibility in some cases of delivering power to the AP. This problem can be overcome by using solar-panel powered APs which we will refer to as solar nodes (SNs). In this thesis we examine the load-balancing problem that arises when two or more SNs are co-located in the same coverage area. We propose and evaluate two algorithms for efficiently distributing the load among them (transferring stations (STAs) from SN to neighboring SNs) and increasing their lifetime by using power saving schemes that co-ordinate the wake/sleep patterns of the SNs based on traffic load. Finally, a Connection Admission Control (CAC) function is proposed that the SN should use in order to provide controlled access to services. We demonstrate through simulations that our proposals can significantly reduce the hardware requirements and cost of SNs and improve the service perceived by STAs in terms of transmission delay.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Single Cell Microinjection Using Compliant Fluidic Channels and Electroosmotic Dosage Control

contributor:
Selvaganapathy, P. R.
Mechanical Engineering

subject:
cell
microinjection
fluid channel
electroosmotic

abstract: The introduction of bio-molecules into cells and embryos is required in the fields of drug development, genetic engineering and in-vitro fertilization. It has been applied to create transgenic mammals and to improve pest and mold resistance in plants. However, the efficient transfection of materials still poses a problem, and a variety of techniques, broadly classified as biochemical and physical means, are actively being developed. One technique that is promising is capillary microinjection as it offers low cytotoxicity, targeted injections and high transfection efficiency. However, this process suffers from low throughput and variability as it is an operator mediated process. Other problems associated with capillary microinjection are limitations on the minimum needle size and variability in transfected volumes due to the use of pressure driven flow for injections. In this thesis we propose a device that employs microfluidic principles to enable cell microinjections in a 'lab on a chip' format and eliminates the problems associated with capillary microinjection. The device is fabricated using poly dimethylsiloxane (PDMS) rapid prototyping and features two separate channel structures-one to supply the targets and the other to supply the reagent. Integrated into the device are a microinjection capillary (10 μm tip diameter) and a suction capillary (0.5mm ID/1mm OD) which is used to immobilize the targets in the channel prior to injection. The actuation of the injection needle into the targets is achieved by the compliant deformation of the flexible PDMS substrate as a result of an externally applied displacement. This is made possible by the selective reinforcement of the PDMS substrate. From testing it was found that the effective needle actuation is 83.8% of the externally applied displacement. The injections occur in a planar configuration therefore providing precise control over the location of injection. Furthermore, the mechanism requires only one degree of freedom to perform injections, and therefore greatly simplifies existing injection techniques which require orientation in a three dimensional space. The limitations of the use of pressure driven flow for injections are overcome by performing reagent injection by electroosmotic flow, which is induced by applying a potential to electrodes embedded in the target and reagent supply channels. The applied potential induces electroosmotic flow through the embedded needle and into the injection target. This provides precise electrical dosage control. The flow rates were obtained by measuring the velocity of the interface between a neutral fluorescent marker and a clear pH 10 buffer solution. The obtained flow rates follow a predictable linear trend and correspond well to theory. The use of electroosmotic flow enables the use of smaller injection needles as it scales more favorably (r^-2) than pressure driven flow (r^-4) and becomes increasingly dominant in smaller dimensions. Present pressure microinjection systems are limited to injection needles with tip diameters larger than 0.2μm due to the high pressures required to dose at smaller dimensions. All components of the device are fully scalable and enable further miniaturization, multiple parallel injections and autonomous functionality. The device requires smaller volumes of samples and expensive reagents and also reduces the time required for performing injections. Overall, it device maintains the advantages of microinjection, while eliminating problems of low throughput, dosage control and restrictions on the injection needle size. The device was successfully used and characterized for the injection of single-cell Xenopus Laevis eggs and Zebrafish embryos.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Functions of the Urinary Bladder In Vivo in the Rainbow Trout

contributor:
Wood, C. M.
Biology

subject:
urinary bladder
bladder
in vivo
rainbow trout
trout

abstract: This thesis examined the function of the urinary bladder in vivo in the freshwater rainbow trout. In the first part of the study two new techniques were developed to examine the possible urine storage and ionoregulatory roles of the bladder in vivo. An indirect approach, using non-catheterized fish, involved "spot sampling" from the bladder to determine urine composition, and measurement of the appearance of ^3H polyethylene glycol-4000 (a glomerular filtration marker) in surrounding water to quantify urination events. The direct approach employed a new external catheterization technique to collect naturally discharged urine. Both methods demonstrated that resting trout urinate in intermittent bursts at 20-30 min intervals, and that natural urine flow rate (U.F.R.) is at least 20 % lower and urinary Na^+ and Cl^- excretion rates at least 40% lower than determined by the traditional internal bladder catheter technique. The urine is stored for approximately 25 min prior to discharge, and significant reabsorption of water and ions (Na^+, Cl^-, K^+, urea, and possibly other substances) occurs via the bladder epithelium during this period; a small residual volume is likely always maintained. The second part of the study employed the new external catheter and the traditional internal catheter to quantify the responses of the bladder, relative to those of the kidney, to two experimental disturbances. Chronic (32 h) infusion with 140 mM NaCl produced isosmotic volume loading without a change in plasma [Na^+], [Cl^-], or acid-base status. The kidney responded with a large increase in glomerular filtration rate (G.F.R.), a smaller increase in U.F.R., and increased reabsorption of water and ions. The bladder responded with a small increase in urination burst volume, a larger increase in burst frequency, and therefore a decreased urine storage time. Despite this increased throughput, Na^+ and Cl^- reabsorption rates across the bladder epithelium actually increased. Reabsorption of urea and K^+ remained constant, despite expected decreases due to decreased urine storage time. A similar infusion with 140 mM NaHCO_3 produced isosmotic volume loading together with metabolic alkalosis reflected m increased blood pH, increased plasma [HCO_3^-], decreased plasma [Cl^-], with no change in plasma [Na^+]. The response of the kidney was similar, though HCO_3^- filtration, reabsorption, and excretion rates all increased, while rates for Cl^- were proportionately lowered; renal Na^+ handling was unaffected. Bladder urination patterns and Na^+ reabsorption were also similar, but there was no evidence of bladder involvement in HCO_3^- secretion or reabsorption (ie. in acid-base regulation). It is concluded that previous studies using internal catheterization have greatly underestimated the ionoregulatory effectiveness of the entire renal system by negating bladder function. The external catheterization technique developed in this thesis provides researchers with a method to collect naturally vented urine, and thereby evaluate the role of the entire renal system, including the bladder, in response to experimental manipulations.

abstract: Thesis

abstract: Master of Science (MS)


title: Net Shape Manufacturing of Bulk Metallic Glass and Prediction of Glass Forming Ability

title: Manufacturing of Bulk Metallic Glass & Glass Forming Ability

contributor:
Shankar, Sumanth
Mechanical Engineering

subject:
net
glass
metallic glass
glass form

abstract: Bulk Metallic Glass (BMG) possesses a variety of extraordinary properties including ultra high elastic limit and strength and has been applied in diverse fields such as industrial coatings, sporting foods, medical devices, defense and aerospace sectors. The cross-section thickness of a few millimeters for cast BMG alloy components limits their application to manufacturing structural components. However, continuing global efforts are underway to increase the critical part size cast with BMG alloys. There are two phases tot his project. Phase 1 investigates the feasibility of using suitable BMG alloys to manufacture a pivot assembly in an Airborne Gravity Gradiometer (AGG) via net shape manufacturing techniques. Success of Phase 1 will enable a quantum leap in the capabilities of the present day AGG devices to successfully and accurately scope the vast untapped mineral and petroleum resources globally. Requirements of high tolerances in the pivot assembly with very specific material properties and a net shape manufacturing route coupled with the lack of any database for BMG alloys were the inherent challenges. Suitable BMG alloys have been identified for this purpose and continued efforts are underway to manufacture the pivot assembly. Phase 2 of this project lays the foundation for a much needed tool to predict the Glass forming Ability of BMG alloys. This will enable to scientifically develop novel BMG alloys to suite specific application in lieu of the current ad-hoc development trends. A viable thermal model to understand the relationship between growth rate of solid phase and melt undercooling during uni-directional solidification coupled with a solidification model based on competitive growth principles have been developed. Novel experiment program and setup have been developed to verify these models.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: SAT-Based ATPG for Digital Integrated Circuits Based on Multiple Observations

contributor:
Nicolici, Nicola
Electrical and Computer Engineering

subject: SAT ATPG digital circuit observation

abstract: This thesis presents a new approach to improve the efficiency of defect screening during manufacturing test of digital integrated circuits through the use of multiple observations during test generation. To address the limitations of test sets generated based on the single stuck-at fault model, we combine the advantages of multiple-detect and detection at all observable outputs in order to generate test sets that can improve surrogate detection. Imposing additional constraints, such as multiple observations, on the test generation process motivates the development of a new constrained automatic test pattern generation (ATPG) work flow that leverages the recent advancements in the Boolean satisfiability (SAT) problem. Building this ATPG work flow brings its own technical challenges and solutions described in detail in this thesis. To assess the effectiveness of the test sets generated by the proposed ATPG work flow, we evaluate them using coverage metrics for fault models that are not targeted explicitly during test generation.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Investigation of the Function of YIHA, An Essential Gene of Unknown Function in Escherichia Coli

title: Investigation of the Function of yihA

contributor:
Brown, E. D.
Biochemistry and Biomedical Sciences

subject:
function
yihA
gene
escherichia coli
e. coli

abstract: Genomic data has led to the realization that nearly one third of the bacterial genes discovered have unknown functions. Promising drug targets are no doubt among the conserved and essential genes, but drug development awaits an understanding of the basic physiological roles of the cryptic bacterial proteins they encode. The pressing need for novel antibiotics mandates investigation of these essential bacterial genes of unknown function. For a subset of such genes, it is becoming increasingly apparent that they may play critical roles in ribosome assembly or function in bacteria. One such essential gene, encoding the putative GTPase YihA in Escherichia coli has been highlighted as a target of particular importance for study (Galperin M.Y. and E.V. Koonin. (2004). 'Conserved hypothetical' proteins: prioritization of targets for experimental study. Nucleic Acids Res 32(18): 5452-63.). To study yihA's function, a strain with yihA under P_BAD control was generated and used to examine the impact of the loss of the gene product on ribosome assembly. Depletion of the YihA protein was found to cause accumulation of 30S and 50S subunits at the expense of 70S ribosomes, and the formation of long filamentous cells apparently incapable of dividing. Chemical genetic interactions were identified through chemical synthetic lethality screening with antibiotics which target the ribosomal A -site, and antibiotics which affect the bacterial cell wall. Finally, investigation of the importance of several patches of basic residues of YihA through mutagenesis and in vivo complementation shows the protein to be tolerant of mutation to non-catalytic residues. The inability of mutants with changes to amino acids important for nucleotide binding to complement represents the strongest evidence to date that the YihA protein relies on GTP binding and hydrolysis as part of its essential function in vivo. The findings of this study support a role for YihA in the poorly understood process of ribosome assembly in vivo, and represent important progress towards realization of this essential process as a source of novel antibiotic targets.

abstract: Thesis

abstract: Master of Science (MS)


title: Analysis and Design of a Low Power 1.2V CMOS Downconversion Mixer Utilising Substrate Biasing

title: Substrate Biasing Techniques on Gilbert Mixer

contributor:
Chen, James
Electrical and Computer Engineering

subject:
mixer
low power
analysis
design
downconversion
substrate bias

abstract: This thesis presents detail theoretical analysis of downconversion Gilbert cell mixer with the improvements on major performance parameters by utilizing different substrate biasing techniques. By modifying the threshold voltage of the switching core, the LO transistors perform more ideally as a perfect switch. It improves the active mixer performances in conversion gain, noise and linearity performances. The techniques are implemented on a 1.2 V low power CMOS downconversion mixer for performance comparisons between simulation and measurements result. They are realized in TSMC 0.18 um CMOS technology. It shows that body-biasing techniques help to increase the switching efficiency of the Gilbert mixer. And a mixer with a better switching provides better performance. With no additional power consumption, the no body effect technique in Design B has shown a 1.5 dB higher in conversion gain, 2 dBm higher in IIP3, and a 0.5 dB lower in NF performance. With the varying biasing technique implemented in Design C, it shows an improvement of 22 dB in conversion gain. Both Design B and C have less than 2 mW power consumption and are suitable for Bluetooth applications. This thesis introduces a stage-by-stage procedure for designing a Gilbert mixer; design tradeoffs at each stage are also discussed.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Design and Testing of EMG Measurement System

contributor:
de Bruin, H.
Electrical Engineering

subject: EMG measure system design test

abstract: Monitoring electromyography signals (EMG) leads to a greater understanding of muscle properties hives insight into how muscles work together to coordinate tasks, and yields information about neuromuscular disorders. In this project we developed a PC based EMG data acquisition and analysis system to record and analysis EMG signals. We tested this system by recording EMG signals from the biceps brachii of a single normal subject. The acquired data was analyzed in both time and frequency domains to determine the behavior of the EMG signal during different experiment conditions. Fast Fourier Transform (FFT) and Short Time Fourier Transform (STFT) were applied during digital signal processing. The FFT only provides the information in frequency domain. STFT is a modification of the Fourier transform in an attempt to retain both time and frequency information during signal analysis. The STFT produces a two dimensional function with time and frequency as variables. Thus the STFT gives information about when in time a given frequency component occurs. The extracted features of EMG are RMS value, mean absolute value, mean power frequency, and median power frequency. The raw EMG signal is collected for 10 seconds. The sampling rate is set to 1000 Hz. The emphases of this project were software development, data collection, and simple signal analysis.

abstract: Thesis

abstract: Master of Engineering (ME)


title: RNA Metabolism and a New Mode of Development in Streptomyces

contributor:
Elliot, Marie A.
Biology

abstract:
Streptomyces are soil bacteria best known for their ability to produce medicinally useful compounds and for their complex life cycle. RNA processing represents a critical layer of regulatory control in bacteria, and RNA cleavage is mediated by ribonucleases (RNases). We probed the roles of RNase III and RNase J in the emerging model system Streptomyces venezuelae. We found both RNases impact the development and metabolism of S. venezuelae, and are essential for ribosome activity and assembly.
While investigating the metabolic changes associated with the RNase mutants, we made a discovery that shifted the focus of my Ph.D. work. For the past 70 years, it had been thought that Streptomyces grow as static colonies. We discovered that when S. venezuelae is grown beside yeast, S. venezuelae grows in a completely novel way termed ‘exploration’. Exploring colonies can rapidly traverse surfaces. Remarkably, exploring colonies release an airborne volatile organic compound (VOC) that serves to induce exploration in physically separated streptomycetes. We identified the VOC as being trimethylamine (TMA), and discovered that this VOC induces Streptomyces exploration by raising the pH of the surrounding environment.
VOCs have important roles in influencing microbial community dynamics, and we analyzed how TMA produced by exploring Streptomyces impacts other soil microbes. We found TMA inhibits the growth of other microbes by raising environmental pH and altering iron availability. Exploring Streptomyces overcome this iron deficiency by producing siderophores, and by upregulating siderophore uptake clusters.
Streptomyces exploration is rapid, and we sought to identify the cellular factors driving exploration. Previous work has shown Streptomyces grow by hyphal tip extension governed by the protein DivIVA. In contrast, many rod-shaped bacteria grow using the protein MreB. We demonstrate that exploratory growth requires contributions from both DivIVA and MreB. Employing two distinct growth mechanisms in this manner is unprecedented in bacteria.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Streptomyces are soil bacteria that produce most clinically used antibiotics. Many regulatory systems control Streptomyces growth and antibiotic production. In all cells, molecular blueprints called DNA are converted into RNA, and RNA is converted into proteins. In this work, we investigated how RNA regulators affect Streptomyces. We found RNA regulators are important for antibiotic production and for the activities of protein assembly factories. It is possible to manipulate these RNA regulators to better understand how Streptomyces produce antibiotics. We also investigated how Streptomyces grow. While it had always been thought Streptomyces grow rooted in place like plants, we found Streptomyces can sometimes rapidly explore their environments. Remarkably, these ‘explorer’ Streptomyces can communicate with other bacteria using airborne signals. This work reveals new ways that bacteria can interact and communicate, and demonstrates that airborne signaling is an important language of communication in microbial communities.


title: Toward a Miniaturized Wireless Fluorescence-Based Diagnostic Imaging System

contributor:
Deen, M.
Electrical and Computer Engineering

subject:
miniature
fluorescence
diagnostic image
diagnostic
wireless

abstract: Fluorescence based spectroscopy and imaging techniques provide qualitative and quantitative diagnostic information about biological systems. Some tissue cells have inherent fluorescence characteristics, and when excited with light at a certain frequency, they can emit light of a slightly longer wavelength; a phenomenon known as autofluorescence. Differences in the autofluorescence emission spectra between healthy and diseased tissue may be used as a non-invasive diagnostic tool for the detection of diseases. In this thesis, I describe the design, fabrication, and testing of a miniaturized fluorescence imaging device for non-invasive clinical diagnosis in the gastrointestinal tract. The device is designed such that it can be turned completely wireless. The system includes three sub-modules: optical imaging, electronics control and image acquisition, and information processing and transmission. These modules were individually developed and tested before being integrated into a complete, externally powered device. The final integrated system is small in size (diameter: ~ 2.5 cm; length: ~ 11 cm). The performance of each individual module and the overall integrated system has been evaluated using fluorescent phantoms. It has been demonstrated that the miniaturized device can acquire spectrally-resolved fluorescence images. It has also been separately demonstrated that the image stream can be transmitted wirelessly. An important outcome of this feasibility study is the identification of important technological issues and pathways for future prototype development.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Algorithms for Embedded Memory Binding in FPGAS

subject: embed memory algorithm FPGA

abstract: Recent advancements in semiconductor fabrication technology have enabled field-programmable gate arrays (FPGAs) with hundreds of embedded memories. Usually, these embedded memories can be configured to work with different widths of address and data buses, In some FPGAs there is also a variety of different types of embedded memories with different capacities and configuration sets. As a consequence, it is becoming cumbersome to bind the data memory of an algorithm to these embedded memories manually. A computer-aided design tool that automates the process of binding embedded memories can save the engineering time for a design, as well as explore different alternatives to bind the data memory with the use of less embedded memories and less amount of peripheral hardware in terms of logic cells of the FPGA. In this thesis, we first motivate the need for an algorithmic solution to the memory binding problem in FPGAs and explain the design trade-offs. Then we present an exact solution for the problem using a branching method to search the solution space exhaustively. However, due to the large solution space and the plenitude of choices in each step of the algorithm, the runtime of the algorithm is far from being acceptable for realistic problems. To manage the runtime, we have developed a fast heuristic approach. Our experimental results show that the heuristic method can achieve a suboptimal solution, which for the small problem instances is shown to be close to the optimal in acceptable runtime. Moreover, when compared to manual solutions, besides substantially improving the implementation time, the heuristic can often enable a more efficient usage of the FPGA logic resources and embedded memories.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: “TREASURE HOUSE TO THE WORLD:” A GLOBAL ENVIRONMENTAL HISTORY OF THE PORCUPINE GOLD RUSH, 1909-1929

contributor:
Egan, Michael
History

subject:
environmental history
natural resources
Canada
Ontario
economic history
transnationalism
geology
mining

abstract:
The discovery of gold at Porcupine Lake in 1909 brought a well-practiced era of ecological change to northern Ontario. By the early twentieth century gold rushes followed predictable patterns. Deforestation, soil depletion, water-shed modification, rapid immigration, transient populations, “get-rich-quick” ambitions, conflicts with Indigenous people, major fires, and hasty infrastructure development characterized multiple rushes in Africa, the Americas, and Australasia. In the aftermath of the nineteenth century mining booms, the 1909 Porcupine rush brought global gold mining knowledge and technology to northern Canada. At Porcupine, experiments in industrial extraction matured into a set of efficient methods for large-scale corporate extraction of low-grade gold. Although historians traditionally frame gold rushes as national or regional events, Porcupine shows how borders were permeable to people, objects, and ideas moving between mining zones to shape local environmental history.
Porcupine’s gold-bearing landscape became a site of convergent historical forces between 1909 and 1929. The rush brought northern Ontario into an international community of mining frontiers at a moment of development in the province’s northern hinterland. Local conditions (such as climate and geology) worked together with transnational networks to shape the land and its communities. Industrial mining also created problems including fires, droughts, and industrial disease. By 1929, Porcupine had become a major player in the global industrial mining industry. The Porcupine rush set the stage for twenty-first century dominance in international gold economy and laid the groundwork for Canada’s modern relationship with nature.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: This dissertation argues that international forces shaped local environmental history in the gold mining district of Porcupine, northern Ontario, between 1909 and 1929. During these years, Canadian mining transformed from a relatively small extractive economy into a large-scale industrial one -- with a host of associated social and environmental consequences. The geological, climatic, and cultural characteristics of the Canadian Shield environment created significant challenges (including fires, floods, rock-falls, pollution, use conflicts, and disease) which required adaptation from the industry’s stakeholders. People solved environmental problems by relying on support from transnational gold mining networks of investors, managers, prospectors, geologists, prospectors, miners, communities, and governments. As a result, Porcupine’s environmental history was shaped by the convergent forces of its gold-bearing geology, an international context, and local Canadian history. Largely complete by 1929, the legacy of Porcupine’s environmental history lives on in the power of Canada’s international mining industry on modern extractive frontiers.


title: Effect of Acoustic Resonance on the Dynamic Lift in Square Tube Arrays

contributor:
Ziada, Samir
Mechanical Engineering

subject:
acoustic
resonance
lift
square tube
array

abstract: An investigation of the dynamic lift on the central tube in square tube arrays is conducted. Three array spacing ratios with P/ D = 3.37, 2.18 and 1.58, corresponding to large, intermediate and small spacing ratios are investigated. These three classes exhibit specific flow characteristics and distinct behavior during acoustic resonance. The aim of the present investigation is to determine the effect of the acoustic pressure field and its contribution to dynamic lift during acoustic resonance. During acoustic resonance there are two sources of dynamic lift. One source is provided by the sound field. The standing wave excited during resonance causes dynamic lift from the acoustic pressure distribution on the surface of the cylinder. In the absence of flow, loud speakers are used to excite the first transverse acoustic mode over a range of sound pressure levels, effectively determining the relationship between the resultant dynamic lift and sound pressure level of the acoustic standing wave. The dynamic lift due to the sound field is well predicted by numerical simulation of the acoustic pressure distribution in the tube array. Using the validated numerical simulation it is possible to extend the results to a large range of cylinder diameter to wavelength ratios. The other source of dynamic lift is provided by the periodic flow though the tube array, known as vortex shedding, which is enhanced during resonance. The total dynamic lift is dependant on the phase shift between the sound field and aerodynamic lift components. For small and intermediate tube arrays, acoustic resonance occurs before coincidence of the natural vortex shedding frequency and the acoustic mode. For the large tube array, frequency coincidence occurs within the resonance range. The phase shift between the dynamic lift due to sound and that due to the aerodynamic lift is small for the pre-coincidence resonance range observed for small and intermediate tube arrays and therefore the total dynamic lift is well predicted by the sum of the magnitudes of the dynamic lift due to the sound field and aerodynamic lift components caused by vortex shedding. Past the frequency of coincidence, a phase jump occurs in the aerodynamic lift causing a large phase shift between the sound field and aerodynamic lift components in the large spacing ratio array. The summation of the aerodynamic lift and the lift due to the sound field over predicts the total dynamic lift measured during acoustic resonance in this case. The present results are used to develop a conservative guideline for estimating the total dynamic lift during acoustic resonance.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Experimental and Numerical Study of Axial-Feed Hot Gas Tube Forming of Polypropylene

contributor:
Jain, Mukesh
Mechanical Engineering

subject:
axial-feed
gas
polypropylene
experiment
numerical study

abstract: Polymeric materials have attracted a lot of attention for the past several decades. Different sectors of manufacturing industry, such as packaging, building and automotive industry have introduced polymeric materials in their applications. Common polymer manufacturing processes include thermoforming and blow molding. In this research, characteristics of a new polymer manufacturing process, referred to as axial-feed hot gas tube forming (HGTF) are studied. Experimental studies were conducted to form a simple axisymmetric component from extruded polypropylene (PP) tube by varying several key process parameters such as internal pressure, temperature and axial feed. Tube shape and deformation characteristics were studied as a function of the above process parameters. In addition, two consecutive material models have been utilized for finite element simulation of axial-feed HGTF of PP tube using a commercial FE code. One of them is conventional hyperelastic Ogden material model and another is more advanced viscoelastic-viscoplastic Augmented Hybrid material model (AHM), that has been recently developed. Simulation results from two models were analyzed and compared with the experimental results and good general agreement has been obtained. Results showed that application of more advanced AHM material model led to improved prediction of part shape and strain distribution over the part profile.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Development of Novel Targets for Cancer-Induced Bone Pain

contributor: Medical Sciences (Division of Physiology/Pharmacology)

abstract: A high proportion of advanced-stage breast cancer patients will experience bone metastases resulting in skeletal-related comorbidities including cancer-induced bone pain (CIBP). CIBP affects the quality of life of these patients and current treatments are associated with dose-limiting side-effects that negatively impact patient care. Novel mechanisms must therefore be explored to identify targeted therapies to address this unmet clinical problem. Targeting cancer-specific mechanisms is one strategy to treat this unique pain state peripherally. Glutamate is a key neurotransmitter and signaling molecule in the central nervous system and peripheral tissues including the bone. Particularly aggressive cancers that metastasize to the bone secrete high levels of glutamate via the glutamate/cystine antiporter (system xc-) which can disrupt normal bone turnover and induce CIBP. Therefore, identification of small molecule inhibitors of glutamate release from metastatic breast cancer cells is a novel approach to targeting CIBP. Using high-throughput screening, library compounds were tested for their ability to reduce glutamate release from MDA-MB-231 cells known to secrete high levels of glutamate through system xc- and induce CIBP in vivo. One compound, capsazepine (CPZ), was confirmed to inhibit the functional unit of system xc− (xCT) and successfully delay the onset of, and reverse nociceptive behaviours in a validated animal model. Another lead compound was found to show potent antagonism against glutaminase (GLS), the enzyme catalyzing the intracellular conversion of glutamine to glutamate. This offered another strategy to target glutamate-induced nociception upstream of xCT activity. The effects of GLS inhibition on CIBP behaviours was tested with the specific GLS antagonist, CB-839 but did not significantly modulate nociception, highlighting a redundancy in glutamine metabolism that confers metabolic flexibility in different cancer cell lines. These studies identify novel molecules to target CIBP and reveal that their antinociceptive effects are dependent on the glutamatergic target and metabolic status of the cancer subtype.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Ocean waves in a multi-layer shallow water system with bathymetry

contributor:
Kevlahan, Nicholas
Computational Engineering and Science

subject:
Multi-layer Shallow water equation
bathymetry,
internal waves,
surface waves,
barotropic mode,
staggered finite volume method.

abstract:
Mathematical modeling of ocean waves is based on the formulation and solution of the appropriate equations of continuity, momentum and the choice of proper initial and boundary conditions. Under the influence of gravity, many free surface water waves can be modeled by the shallow water equations (SWE) with the assumption that the horizontal length scale  of the wave is much greater than the depth scale and the wave height is much less than the fluid's mean depth. Furthermore, to describe three dimensional flows in the hydrostatic and Boussinesq limits, the multilayer SWE model is used, where the fluid is discretized horizontally into a set of vertical layers, each having its own height, density,  horizontal velocity and geopotential. In this study, we used an explicit staggered finite volume method to solve single and multilayer SWE, with and without density stratification and bathymetry, to understand the dynamic of surface waves and internal waves. We implemented a two-dimensional version of the incompressible DYNAMICO method and compare it with a one-dimensional SWE. For multilayer SWE, we considered both two layer and a linear stratification of density, with very small density gradient, consistent with Boussinesq approximation. We used Lagrangian vertical coordinate which doesn't allow mass to flow across vertical layers. Numerical examples are presented to verify multilayer SWE model against single layer SWE, in terms of the phase speed and the steepness criteria of wave profile. In addition, the phase speed of the barotropic and baroclinic mode of two-layer SWE also verified our multilayer SWE model. We found that, for multilayer SWE, waves move slower than single layer SWE and get steeper than normal when they flow across bathymetry. A series of numerical experiment were carried out to compare 1-D shallow water solutions to 2-D solutions with and without density as well as to explain the dynamics of surface wave and internal wave.
We found that, a positive fluctuations on free surface causes water to rise above surface level, gravity pulls it back and the forces that acquired during the falling movement causes the water to penetrate beneath it's equilibrium level, influences the generation of internal waves. Internal waves travel considerably more slowly than surface waves. On the other hand, a bumpy or a slicky formation of surface waves is associated with the propagation of internal waves. The interaction between these two waves is therefore demonstrated and discussed.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: In the modelling of ocean wave, the formulation and solution of appropriate equations and proper initial and boundary conditions are required. The shallow water equations (SWE) are derived from the conservation of mass and momentum equations, in the case where the horizontal length scale  of the wave is much greater than the depth scale and the wave height is much less than the fluid's mean depth. In multilayer SWE, the fluid is discretized horizontally into a set of vertical layers, each having its own height, density, horizontal velocity and geopotential. In this study, we used an explicit staggered finite volume method to solve single and multilayer SWE, with and without density stratification and bathymetry, to understand the dynamic of surface waves and internal waves.  A series of numerical experiments were carried out to validate our multilayer model. It is found that, in the presence of density differences, surface waves for the multilayer SWE move slowly and get more steep than normal when they flow across bathymetry. Also, a positive fluctuations on free surface generates internal waves at the interior of ocean which propagate along the line of density gradient.


title: THE CLINICAL IMPACT OF HOSPITALIZATION DUE TO RESPIRATORY SYNCYTIAL VIRUS AND HUMAN METAPNEUMOVIRUS AS COMPARED TO INFLUENZA A IN THE ADULT POPULATION

contributor:
Smieja, Marek
Health Research Methodology

abstract: Background: Respiratory Syncytial Virus (RSV) and Human Metapneumovirus (hMPV) are major respiratory pathogens in children, and are increasingly recognized as causes of significant illness in the adult population, particularly in seniors. Furthering our understanding of the clinical context of these illnesses will inform policy and practice on how best to use treatment and preventative measures when they become available. Methods: First, we conducted a retrospective chart review of adult patients hospitalized with RSV, hMPV, or Influenza A (2011-2016) at St. Joseph’s Healthcare Hamilton. All RSV and hMPV inpatients were included in the study, and a random sample of inpatients with Influenza A in each year were then selected. Second, we conducted an analysis of The FOREVER cohort (2011-2014), a linked laboratory and administrative data set that included the three major acute care centres in the Hamilton/Niagara Region. Outcomes were length of hospital stay, mortality, and changes in disposition post-hospitalization. Results: Patients with RSV (p<0.001) and hMPV (P=0.04) were observed to be older than those with influenza A and be more likely to reside in long term care facilities. Moreover, patients that were hospitalized with RSV and hMPV had longer lengths of hospital stay and higher odds of mortality after controlling for age, sex, and comorbid conditions in multi-variable models.  There were no differences observed in changes of disposition following hospitalization between the three infections groups. There was a high level agreement between the two methodologies with regard to baseline characteristics, length of stay, and mortality.  Differences were observed in the proportions of patients that were admitted to the ICU during their hospital stay and the proportion that were discharged to long term care facilities. Conclusions: RSV and hMPV in adult inpatients was half as common as Influenza A, and had comparable, if not worse outcomes.

abstract: Thesis

abstract: Master of Public Health (MPH)


title: Surface Colour Effects on the Thermal Behaviour and Mechanical Properties of Hot Mix Asphalt

contributor:
Stolle, Dieter
Civil Engineering

subject:
color
thermal
behavior
properties
hot mix asphalt

abstract: The focus of the study was to evaluate the effect of placing hydrated lime on the surface of asphalt concrete pavement. The study assesses the influence of hydrated lime on both the peak surface temperature as well as the temperature profile of the pavement with depth. The amount of lime that would yield the optimal temperature reductions without placing excess ineffective material was selected. To address the aforementioned goal, eight Superpave mix samples were prepared in the lab and compacted at the design compaction temperature to achieve a relatively consistent percent of air voids. All samples were compacted using a vibratory compactor to simulate real field construction procedures and conditions. To examine the effect of hydrated lime, surface temperatures as well as with-depth temperature measurements were made with an infrared camera, and thermocouples buried into the pavement, respectively. The same tests were performed at a field site with a newly laid down pavement. To minimize variables, the field Hot Mix Asphalt (HMA) pavement was of the same design as that used to prepare the lab samples. The effect of temperature on the mechanical properties of HMA mixtures used in Ontario; namely Superpave SP12.5FC2 PG64-28, SP12.5FC2 PG70-28, SP19.0, and Stone Mastic Asphalt (SMA), was assessed. The mechanical properties studied include rutting susceptibility, fatigue resistance, and resilient modulus. Thirty two samples were prepared in the laboratory and compacted at the design compaction temperature and percent air voids. For each mix, two samples were used to test rutting susceptibility, three samples were used to test fatigue resistance, and three samples were used to test the resilient modulus of the mixes. With regards to rutting, the samples were tested in the Asphalt Pavement Analyzer (APA) at four different temperatures in order to give a complete rutting versus temperature profile. Three samples of each mix were tested to measure the resilient modulus at different temperatures using the Nottingham Asphalt Tester (NAT). Lastly, the fatigue resistance for each mix was assessed in the NAT with each of the three samples tested at a different strain to provide a complete picture of the mix behaviour when subjected to fatigue. The stiffness characteristics of the newly laid down in-situ pavement was determined using the Light Weight Deflectometer (LWD). Results indicate that placing 100g/m^2 of hydrated lime on the surface of the hot mix asphalt pavement was the optimum surface treatment while avoiding the placement of excess ineffective material. This level of surface treatment led to temperature reductions that significantly improved the mechanical properties of asphalt concrete. Using the increased resilient modulus, consistent with the temperature reductions, it was shown, by carrying out an analysis using KENLAYER, that the design life of a pavement could be increased from approximately 25 to 33 years, from 20 to 30 years and from 12 to 20 years corresponding to cool, intermediate and hot weather conditions, respectively.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Cutting Tool Edge Design for Longer Tool Life

subject:
cutting tool
design
tool
tool life

abstract: In metal cutting, the effects of edge preparation and tool wear are considered most critical, as they directly determine tool life, surface finish and properties of the subsurface layer. Proper selection and application of cutting tool edge preparation is one of the basic factors for a successfully manufactured and correctly performing cutting tool. In this regard, the use of cutting tools with honed and chamfered edges is ever increasing. This thesis develops a procedure to design a subtle feature on the cutting edge of an insert, which mimics as closely as possible the natural wear that occurs in the initial stage of wear and arrive at a geometry that is known to lead to stable wear. In this case the geometry that would naturally occur is established with minimal subsurface damage, thus leading to a longer tool life. Turning test data collected showed that using a 50(mu)m chamfer on the rake face of the insert could minimize tool flank wear. By applying a special coating on this newly created geometry, a significant increase in the stable stage of wear and an overall improvement in performance and productivity have been observed. The analysis of chip morphology showed an improved behavior in the case of chamfered coated inserts.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Simulation of Flow Pulsations in Gap Geometries Using Unsteady Reynolds Averaged Navier-Stokes Modelling

contributor:
Lightstone, Marilyn
Hamed, Mohamed
Mechanical Engineering

subject: flow pulse gap geometries reynolds navier-stokes

abstract: An unsteady Reynolds Averaged Navier-Stokes (URANS) based turbulence model, the Spalart-Allmaras (SA) model, was used to investigate the flow pulsation phenomenon in compound rectangular channels for isothermal flows. The computational fluid dynamics (CFD) commercial package ANSYS CFX-11.0 was used for the simulations. The studied geometry was composed of two rectangular subchannels connected by a gap, on which experiments were conducted by Meyer and Rehme [34] and were used for the validation of the numerical results. Two case studies were selected to study the effect of the advection scheme. The results using the first order upwind advection scheme had clear symmetry and periodicity. The frequency of the flow pulsations was underpredicted by almost a factor of two. Due to the inevitable numerical diffusion of the first order upwind scheme, it was more appropriate to use a second order accurate in space advection scheme for comparison with the experiments. The span-wise velocity contours and the velocity vector plots at planes parallel to the bulk flow, together with the time traces of the velocity components at selected monitor points showed the expected cross-flow mixing between the subchannels through the gap. Although the SA model does not solve directly for the turbulence kinetic energy, a kinetic energy associated with the unsteady solutions of the momentum equations was evaluated and qualitatively compared with the experimental turbulence kinetic energy. The calculated kinetic energy followed the trends of the experimental turbulence kinetic energy at the gap area, predicting two peaks at the edges of the gap. The dynamics of the gap pulsations were quantitatively described through temporal auto-correlation and auto-power spectral density functions and the numerical predictions were in agreement with the experiments. Studies on the effect of the Reynolds number and the computational length of the domain were also carried out. The numerical results reproduced the relationship between the Reynolds number and the frequency of the auto-power spectral density functions. The impact of the channel length was tested by simulating a longer channel. It was found that the channel length did not significantly affect the predictions. Simulations were also performed using the (kappa) -(epsilon) model. While flow pulsations were predicted with this model, the frequency of the pulsation was in poor agreement with the experimentally measured value.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: The Effect of Radiation on Saw Resonators

contributor:
Smith, Peter
Electrical and Computer Engineering

subject: radiation SAW resonators

abstract: SAW devices are known for their ability to withstand severe operating conditions. However, their data sheets generally provide very little information on their susceptibility to external factors other than temperature. In particular, no mention is made of their sensitivity to ionizing and non-ionizing radiation, even though they are being used in applications where such radiation is present. In this thesis, we report on experiments that we have conducted to measure the impact of intense gamma and neutron radiation on quartz SAW resonators. Packaged commercial 434 MHz quartz SAW resonators (RFM RP1308) were placed at the output of a Colbalt 60 source and exposed to gamma radiation of up to 50 Mrads. Additional devices were positioned in close proximity to the enriched uranium core of the McMaster University Nuclear Reactor and exposed to intense neutron radiation of 4.5 x 10^12 neutrons/cm^2s for up to 40 seconds. After waiting for a necessary cool-down period, the irradiated SAW resonators were placed in the feedback loop of a custom oscillator to measure the shift in output frequency as a function of radiation exposure. Small changes in the oscillator frequency of up to 15 ppm for the gamma radiation and of up to 10 ppm for neutron radiation were obtained in the experiments. However, no clear relationships were observed between the amount of radiation exposure and frequency shift in either case.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Traffic Scheduling with Efficient Channel Assignment in WLAN Mesh Networks

contributor:
Todd, Terence
Electrical and Computer Engineering

subject: WLAN network traffic schedule channel assignment

abstract: Wireless mesh networks have received increasing interest in recent years due to the fast expanding Wi-Fi market. More and more, individual communities and companies are beginning to set up intranets with multiple Wi-Fi access points, so that clients can communicate using wireless connections. Because the traditional IEEE 802.11 standard cannot provide efficient performance for mesh networks, the IEEE set up a task group in 2001 to establish a wireless mesh network standard, IEEE 802.11s. For compatibility, IEEE 802.11s will be an extension of the IEEE 802.11 MAC/PHY, and as a result, the new standard has inherited both the pros and cons of IEEE 802.11. Co-channel and inner-channel interference are the dominant factors affecting the system performance of wireless networks. Since there are a number of available non-overlapping channels one can always use these in order to eliminate inner-channel interference. However, the number of channels is not sufficient for an ESS Mesh if channel reuse is not considered, not only because of the network size, but also because of the non-licensed nature of the IEEE 802.11 PHY ISM band, where the network will suffer interference from other co-located networks. For this reason, channel reuse in an ESS Mesh is essential and reducing co-channel interference is a key issue in channel assignment. In this thesis, we investigate the performance of deterministic traffic scheduling with channel assignment in an ESS Mesh based on a TDMA MAC framework while still using the IEEE 802.11 PHY. We first analyze an upper bound on channel assignment performance, considering both binary interference models and cumulative interference models. Then, a scheduling solution for deterministic traffic is proposed, based on heuristic channel assignment and path selection algorithms. Our simulation results show that the scheduling solution is feasible and the performance is close to the theoretical value.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Perfectly Matched Layer (PML) for Finite Difference Time Domain (FDTD) Computations in Piezoelectric Crystals

contributor:
Smith, Peter
Electrical Engineering

subject:
crystal
piezolectric
time domain
PML
perfect match layer
FDTD
finite difference time domain
computation

abstract:
The Finite-Difference Time-Domain (FDTD) method has become a very powerful tool for the analysis of propagating electromagnetic waves. It involves the discretization of Maxwell's equations in both time and space that leads to a numerical solution of the wave propagation problem in the time domain. The technique's main benefits are that it permits the description of wave propagation in non-uniform media, it can easily accommodate a wide range of boundary conditions, and it can be used to model nonlinear effects as well as the wave behaviour near localized structures or material defects. In this study, we extend this technique to mechanical wave propagation in piezoelectric crystals. It is observed to give large reflection artefacts generated by the computational boundaries which interfere with the desired wave propagation. To solve this problem, the renowned absorbing boundary condition called perfectly matched layer (PML) is used. PML was first introduced in 1994 for electromagnetic wave propagation. Our research has further developed this idea for acoustic wave propagation in piezoelectric crystals.
The need to improve the large reflection artefacts by introducing a finite thickness PML has reduced acoustic wave reflection occurring due to practical errors to less than 0.5 %. However, it is found that PML can generate numerical instabilities in the calculation of acoustic fields in piezoelectric crystals. Theses observations are also discussed in this report.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Essays on subsidized health insurance and health-related quality of life

contributor:
Hurley, Jeremiah
Sweetman, Arthur
Health Policy

subject:
subsidized health insurance
health-related quality of life

abstract:
This dissertation comprises three main chapters, book-ended by an introduction and a concluding chapter. Chapters 2 and 3 examine the impacts of health insurance programs in the Philippines and Indonesia on healthcare utilization, healthcare expenditures, and health outcomes. Chapter 4 then examines the age-related trajectories of health-related quality of life of Canadians with diabetes.
In Chapter 2, we examine the impact of the national health insurance program of The Philippines on maternal and health outcomes among poor mothers. We find that the program is associated with greater likelihood of prenatal care visits, facility-based birth delivery, and post-natal care, and the impact is most pronounced among the poorest women, but we do not observe improvements in birthweight. In Chapter 3, we evaluate the impact of Jamkesmas, the largest subsidized health insurance in Indonesia, on healthcare utilization, health outcomes, and healthcare expenditures. We find that Jamkesmas is associated with higher probability of using outpatient care and inpatient care and lower out-of-pocket healthcare expenditures, but no significant impact on catastrophic healthcare expenditures and health outcomes.  In Chapter 4, we characterize the age-related-trajectories of health-related quality of life of Canadians with diabetes. We find that women and low-income individuals with diabetes experience a lower health-related quality of life trajectories, but there is no evidence that the rate of deterioration of their health-related quality of life is faster than their counterparts without diabetes.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: Tissue Engineering Cells for Allogeneic Trasnplantation

subject: engineering tissue allogeneic transplant

abstract: The immune response is a major barrier to the successful transplantation of organs and tissues required in the treatment of many human diseases. Although the field of tissue engineering was created to address the shortage of human organs and tissues, the immune response remains a substantial challenge, impeding the development of allogeneic biological substitutes to repair, replace and regenerate tissues. Specifically, the T cell mediated immune response initiated through the recognition of cell surface Major histocompatibility complex Class I (MHCI) molecules is the primary cause of acute allograft rejection. In nature, viruses have evolved many mechanisms to exploit weaknesses of the T cell response to evade detection. Viral mechanisms to modulate the MHCI molecule can be effectively applied to allogeneic cells in a tissue-engineered construct to evade detection by CD8+ Cytotoxic T Lympocytes (CTLs) and Natural Killer (NK) cells of the immune system. We demonstrate the successful application of a retroviral vector to over-express the Kaposi's sarcoma-associated herpesvirus (KSHV) immunomodulatory protein, MIR2, in human monocyte-like leukemia cells to differentially downregulate cell surface MHCI, ICAM-1 and B7-2 molecules. We also developed a novel flow cytometry-based cytotoxicity assay to demonstrate that this differential downregulation of immunoactive molecules has the functional effect of significantly reducing CTL-mediated cytotoxicity, without altering NK-mediated cytotoxicity. We believe that this approach provides a potential solution to circumvent the acute immune rejection of allografts in vivo, and can also lead to the development of "universal" donor cells for tissue engineering applications that will not require anti-rejection drugs.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Prediction of Risk of Harm of Inpatient Aggressive Behaviours in St Joseph’s Healthcare Hamilton

contributor:
Hassini, Elkafi
Bieling, Peter J.
eHealth

abstract:
Inpatient violence risk prediction is a priority for safety and quality control purposes. The aims of this retrospective study is: 1) analysing the performance of the Risk of Harm to Others Clinical Assessment Protocol (RHO CAP) in predicting the risk of harm within St Joseph’s Healthcare Hamilton; 2) identifying the most important risk factors associated with harmful incidents in inpatient mental health; 3) developing an alternative algorithm to predict the risk of harm in inpatient settings; 4) analysing the performance of the RHO CAP among patients who did not commit any aggression. Data from January 2016 to December 2017 have been anonymized and collected, for a total of 870 episodes of inpatient aggressions perpetrated by 337 patients. Two main sources of information have been used: the Resident Assessments Instrument for Mental Health (RAI-MH), and an internal report of the aggression incidents. We develop a Bayesian probabilistic classifier, a logistic regression, to investigate the risk factors for harmful incidents and propose a predictive model for risk of harm.
The RHO CAP has demonstrated a better performance in discriminating which patients were more at risk to commit some type of aggression than at identifying the risk of harm among those who will commit aggression. The factors most significantly associated with harmful incidents were age, history of violence to others, police intervention for violent behaviour, and a diagnosis of psychosis. The proposed predictive model showed an overall accuracy of 75%. It focuses on four diagnoses (the most frequent diagnoses associated to aggression in our sample), age, history of violence to others and police intervention for violent behaviour, and inappropriate behaviour within the social context.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Violence in inpatient psychiatric represents an issue for patients and clinical staff, and impacts significantly the quality of the health care services delivered. This retrospective study focuses on violence risk prediction at St. Joseph’s Healthcare Hamilton, between 2016 and 2017. We studied the predictive performance of a clinical indicator, the Risk of Harm to Others Clinical Assessment Protocol (RHO CAP), embedded in a mandatory assessment tool for psychiatric facilities in Ontario, the Resident Assessment Instrument for Mental Health (RAI-MH). After analysing the performance of this indicator and studying the most important factors associated with harmful aggressions, we develop an algorithm to predict the risk of harm in inpatient settings. Our results stress the importance of the RHO CAP in support of a safer environment and a higher quality of care. The proposed predictive model is an attempt towards a further improvement for predicting inpatient risk of harm.


title: Application of Evolutionary Computation - Genetic Algorithm in the Unified Model Design Considerations for ACSR

contributor:
Findlay, Raymond
Electrical and Computer Engineering

subject:
evolution
computation
genetic
algorithm
ACSR
unified model

abstract: Aluminum Conductor Steel Reinforced (ACSR) conductors have been applied in electric power transmission and distribution for over 80 years. Research about ACSR includes its possible properties in electrical, mechanical, and thermal areas. We postulate that these properties predict certain behaviours in power transmission and distribution lines. Four models have been established by various authors for determining conductor behaviour. They are the electromagnetic, mechanical, radial conduction, and steady-state thermal models. These models were developed independently,. Although they can be used in their fields individually, there are no experimental studies verifying a combined model. Also, using them separately does not yield the required information for determining conductor performance. The unified model connects these models probabilistically by considering power system loads and meteorological factors. Based on the unified model and its modules, it is possible to use mathematical tools to optimize the ACSR design and analyze conductor characteristics when conductor parameters are changed,. Evolutionary Computation is an optimization process simulating natural evolution on the computer. Instances based on evolutionary principles are Evolutionary Algorithms that historically include Genetic Algorithms, Evolution Strategies, and Evolutionary Programming. Genetic Algorithms are used in the optimization of multi-dimensional problems in this work. Evolutionary Algorithms are empirically robust in finding near-optimal solutions to complex problems through parallel searches of solution space. Evolution Computations imitates natural evolution and genetic variation, and lays the mathematical foundation for problems in which many inputs are variable. Especially, Genetic Algorithms are extensively applied in engineering to solve problems without satisfying gradient descent, deterministic hill climbing, or purely random search. This project introduces the Evolutionary Algorithms and applies the Genetic Algorithms to the unified models. The problem solved by applying Genetic Algorithms to optimize the unified model is to select optimum multi-dimensional input parameters for the model. This provides an effective way to find conductor size for optimizing conductor design. The results give the variation of electrical, thermal, and mechanical characteristics according to conductor loss changes and predict the variation ranges of electric and magnetic fields of three-layer conductors within ASTM standards. The procedure to apply Genetic Algorithms to optimize ACSR design is unique to the problem. Objective functions are found according to the characteristics of each model. The results are put into the unified model. Comparing results gives rules to change geometrical parameters of ACSR to reach minimal Joule loss.

abstract: Thesis

abstract: Master of Engineering (ME)


title: The Effect of Resistance Training on Muscle Protein Turnover in the Fed State

contributor:
Phillips, Stuart
Kinesiology

subject: muscle protein resistance training fed state

abstract: Resistance exercise results in an increase in muscle protein synthesis (MPS); however, in the fasted state net muscle protein balance (synthesis minus breakdown) remains negative. With the ingestion of post-exercise amino acids, or protein, net protein balance becomes positive and protein accretion can occur over time. Previously, we found that resistance training elevated resting, fasted, mixed MPS, but blunted the acute resistance exercise-induced rise in MPS. We aimed to determine how resistance training would affect mixed MPS chronically and acutely, in the fed state. Young men (N = 10, 21 ± 0.47 yrs, BMI = 25.9 ± 1.4 kg·m^-2; means± SD) completed an 8-week unilateral leg resistance training protocol which consisted of knee extension exercise performed at ~80% 1 repetition maximum (1 RM) and resulted in one leg being trained (T), while the contralateral leg served as an untrained (UT) control. Strength gains were 3-fold greater in the T versus the UT leg (P < 0.05). As well, mean fibre cross-sectional area of Type I and Type II fibres increased (P < 0.05) in the T leg only. Following training, in the fed state, subjects underwent primed constant infusions of [ring-d_5 or -_13C_6]phenylalanine or d_3-(alpha)-ketoisocaproic acid in a randomized counterbalance manner to determine rates of MPS using the precursor product equation for incorporation into mixed muscle proteins, sampled via muscle biopsy of the vastus lateral is. MPS was assessed at rest, acutely following a bout of resistance exercise, which was at the same relative intensity for both legs, and approximately 28 h after the resistance exercise bout. Rates of MPS at rest were unchanged following training (P = 0.97). Following the resistance exercise bout, rates of MPS were elevated acutely in both the T and UT legs (4 h post-exercise; P < 0.01), but returned to baseline levels by 28 h post-exercise in the T leg only. We conclude that while resistance training did not alter resting MPS, it did affect the time course of MPS following an acute bout of resistance exercise compared to the UT leg. Hence, when taken with our previous results we conclude that resistance training attenuates the MPS response to an acute bout of resistance exercise when loads are matched at the same relative intensity, but the response is not altered by the nutritional status of the individual.

abstract: Thesis

abstract: Master of Science (MS)


title: Promoting and Enabling Adherence to Resistance Training Following Cardiac Rehabilitation

title: Resistance Training and Cardiac Rehabilitation

contributor:
Bray, S. R.
Kinesiology

subject:
promote
enable
resistance training
cardiac
rehab

abstract: The mortality/morbidity and quality of life benefits of exercise-based cardiac rehabilitation (CR) are well established, yet adherence to exercise is generally poor post-discharge. Recent trials have attempted to enhance adherence to aerobic activities during transition from CR to home-based exercise. However, these trials have not addressed resistance training, which is also an integral part of many participants' CR exercise routines. Because accessibility to familiar training equipment (e.g., weight machines) and instruction may be limited for many patients upon completion of CR, poor adherence to this beneficial form of exercise can be resultant. The purpose of this study was to examine the effects of a brief intervention involving the provision of a motivation-enhancing instructional manual and elastic Thera-Bands® on self-efficacy for, outcome expectancies for, and adherence to, upper body resistance exercise. It was hypothesized that participants receiving the intervention would report higher self-efficacy, outcome expectancies and greater adherence than those in a standard care control condition. The study was a randomized controlled trial involving informed and consenting CR participants recruited from an established outpatient CR programme at a major urban hospital (N = 40; n_males = 32; M_age= 61.20 ± 11.10). Participants in the intervention group (n=20) received an orientation to home-based upper body resistance training, a theory-based instructional manual designed to enhance self-efficacy and outcome expectations, and Thera-Bands®. The standard care control group received an orientation to home-based upper body resistance training and standard care CR follow-up (n=20). Participants completed baseline measures of self-efficacy for performing resistance training and activities of daily living as well as outcome expectancy measures one week prior to discharge from CR. The same measures were completed again one week later (i.e., at the end of the CR program), and at 4-weeks post-discharge. Participants logged their sets of upper-body resistance exercises continuously throughout the 4-week period following completion of the CR program. There were no differences between groups on any of the study variables at baseline. Participants in the intervention condition reported higher self-efficacy and outcome expectations for resistance training than controls at the 4-week follow-up assessment. Adherence to resistance training was significantly greater with the intervention group completing over twice as many (105%) sets over the four weeks than the control group. Maintaining or increasing upper body strength is an important outcome of CR as it relates to the performance of many activities of daily living. However, adherence to resistance exercises may be difficult upon completion of supervised, facility-based CR. This study illustrates that the provision of a motivation-enhancing instructional manual and low cost materials has a positive impact on self-efficacy, outcome expectations and adherence to resistance training, and may help participants make a successful transition to home-based resistance exercise.

abstract: Thesis

abstract: Master of Science (MS)


title: Sound Generation By Flow Over Multiple Shallow Cavities

subject:
multiple cavities
corrugated pipes
aeroacoustic source
fluid-structure interaction
flow-sound interaction
PIV

abstract:
Corrugated pipes are widely used in offshore gas and oil fields for their flexibility while offering local rigidity. However, self-sustained pressure pulsations associated with the flow in corrugated pipes results in a noisy environment, high running costs and eventually structure fatigue failure upon long exposure. Recent literature has addressed either the flow over a single cavity or the global oscillations. The current research aims at understanding the flow over multiple cavities as a first step to correlate the rich single cavity literature and the actual corrugated pipe problem with the ultimate goal of predicting oscillations amplitude in corrugate pipes.
The standing wave method (SWM), which is an efficient experimental tool, has been successfully adapted in the first phase of the project to measure the source of multiple cavity configurations. One, two and three-cavity configurations have been investigated by means of the SWM. The source non-linearly becomes more pronounced as the number of cavities increases. The cavity length (L) is still found to be the appropriate length scale to define the oscillation dimensionless frequency (the Strouhal number). The measured source data have been successfully employed in a semi-empirical model to predict the amplitude of the self-excited oscillations. Accurate model performance is achieved for the single, double and triple cavity configurations. Including the absorption losses at the cavity corners has been found to be crucial for the model prediction accuracy.
The separation distance (Lp) effect on the generated source is investigated for two and three-cavity configurations using the SWM over a practical range of spacing ratios. At extremum spacing ratios of (Lp/L) 0.5 and 1.375, constructive hydrodynamic interference associated with strong sources has been observed. At high excitation levels the source consistently becomes weaker upon increasing the spacing ratio. The reported trends are consistent for both the double and triple cavity configurations. However, the destructive interference spacing ratio is found to depend on the number of cavities indicating a relatively more complicated interaction mechanism. The different interaction patterns have been analytically interpreted based on the synchronization of the hydrodynamic cycle of the cavity shear layer and the disturbance convection along the pipe spacing between the cavities. Moreover, the three-cavity constructive interference cases have been visualized using Particle Image Velocimetry (PIV). The source evaluated based on the PIV data and applying Howe’s analogy revealed each cavity share of the global source, which fairly agrees with the SWM measured source.
The source contribution due to gradually increasing the number of cavities is investigated using the SWM up to a six-cavity configuration. The source contribution reaches asymptotically a consistent value starting from the fourth cavity. This persistent contribution defines a building unit cavity source which is representative of a general cavity in a long corrugated pipe. The building unit source fairly agrees with the ninth-cavity source in a twelve-cavity configuration extracted by means of the PIV technique. Finally, a predication model, based on the building unit source, successfully predicts the oscillations amplitude of a twelve-cavity configuration, which serves as a model for a corrugated pipe section.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Development of an Electrical Impedance Tomography System for Breast Cancer and Applications of Multivariate Statistical Methods for Image Improvement

title: EIT System Development & Multivarite Image Improvement

contributor:
MacGregor, John
Moran, Gerald
Biomedical Engineering

subject:
electrical impedance
tomography
breast cancer
cancer
multivariate statistical method
image
improvement

abstract: This thesis consists of three sections, the first two deal with the development and testing of an electrical impedance tomography prototype system for imaging breast cancer. The third section sues mutlivariate statistical methods to improve EIT image quality. The McMaster EIT System Mk1.0 is the resultant system of the system development. The EIT system is a 48 electrode, single current source, serial acquisition device with an operational frequency between 100Hz to 125kHz. The device is able to inject current between any two electrodes and is able to perform single or differential measurements on any two electrode pairs. The system is equipped with a virtual phase-lock loop and is capable of paramatic imaging. The system was tested using tests common to most electrical devices and specifically designed for EIT systems, to both benchmark the system and detect any errors. The testing revealed the device while able to produce viable EIT images; system suffers from a large stray capacitance. Due to stray capacitance the system injection amplitude accuracy varies with frequency and load. The system SNR is over 100dB with a 125kHz signal with a 5mA signal and compares favourably with existing EIT systems. The CMRR of the system closely tracked the published CMRR of the underlying commercial components and is comparable to existing systems. A second source of error which needs to be rectified in future deigns is the high contact impedence; which causes high direct current offset. Multivariate testing was used to detect errors which could not be easily discovered using conventional testing. The testing, performed iteratively detected several electronic errors which were fixed during development of the device. Six related models were developed for system noise, each with a different set of underlying assumptions about the source of noise. Of the models only one model proved to be a success on both qualitative and quantitative analysis of sample data sets. Finally an alternate model to the Cole-Cole parametric imaging based on PCA was proposed. The model proved to be better at modeling the underlying tissue variations in the presence of noise than Cole-Cole based models. The prototype EIT system presented in this thesis is a viable EIT system, but is in need of improvements to shielding to improve system performance. Also in need of improvement is the operational frequency and modifications toward a distributed architecture. The multivariate methods used for modelling system noise and tissue should be combined into one method for maximum benefit.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: The Effect of Growth Facotrs and Extracellular Matrix Materials on the Growth and Differentiation of Microencapsulated Myoblasts

title: Growth and Differentiation of Encapsulated Myoblast

contributor:
Jacobs, R.
White, B.
Biology

subject:
microcapsule
growth factor
extracellular matrix
myoblast

abstract: An alternative gene therapy method, non-autologous somatic-gene therapy, is the use of a genetically modified universal cultured cell line that can be implanted into different allogeneic recipients. When used as recombinant cells in microcapsules, myoblasts possess several advantages over other cell types, namely their ability to terminally differentiate thus preventing overcrowding within the capsular space. However, encapsulated myoblasts demonstrate decreased proliferation and myogenic differentiation when compared to unencapsulated myoblasts due to the unnatural capsule environment. This study aims to improve the microcapsule environment by incorporating basic fibroblast growth factor (bFGF) and insulin-like growth factor-11 (IGF-11) and the extracellular matrix materials, collagen, laminin-1 and merosin (laminin-2) within the microcapsules in an attempt to mimic the natural surrounding required for myoblast growth and differentiation. While bFGF lead to significant increases in encapsulated myoblast proliferation, it did not appear to be an ideal choice for optimizing the microcapsule environment due to its inhibitory effect on differentiation and the relative cost in therapeutic delivery of proteins. Both merosin and the combination of laminin and merosin together provide a better alternative for increasing myoblast growth and survival within microcapsules since they have no apparent inhibitory effect on myogenic differentiation, and produce similar proliferative results seen when using bFGF. In terms of differentiation, the addition of IGF-11 to the microcapsules or the use of a myoblast cell line overexpressing IGF-11, aid in increasing the myogenic differentiation of encapsulated myoblasts, however, differentiation levels still do not approach those seen in unencapsulated myoblasts. The positive results obtained with the growth factors and matrix materials employed in this study are important steps towards the optimization of microcapsules by improving both the proliferation and differentiation of encapsulated myoblasts. However, more study is needed to elucidate possible solutions to the continued problem of decreased differentiation of myoblasts within APA microcapsules in order to achieve myogenic differentiation that is comparable to what is seen in unencapsulated myoblasts.

abstract: Thesis

abstract: Master of Science (MS)


title: Differentiation of Recombinant Myoblasts in Alginate Microcapsules

contributor:
Chang, P. L.
Biology

subject: recombinant myoblast alginate microcapsule

abstract: A cost effective approach to the delivery of therapeutic gene products in vivo is to immunoprotect genetically-engineered, universal, non-autologous cells in biocompatible microcapsules before implantation. Myoblasts may be an ideal cell type for encapsulation due to their inherent ability to differentiate into myotubes, thereby eliminating the problem of cell overgrowth within the capsular space. To evaluate the interaction between the differentiation program and the secretory activity of the myoblasts within the microcapsule environment, we transfected C2C12 myoblasts to express human growth hormone and followed their expression of muscle differentiation markers, such as creatine phosphate kinase (CPK) protein and up-regulation of muscle-specific genes (ie. myosin light chains 2 & 1/3, Troponin I slow, Troponin T, myogenin and MyoD1). As the transfected myoblasts were induced to differentiate for up to two weeks, their myogenic index (i.e. the percentage of multinucleate myoblasts) increased from 0 to ~50%. Concomitantly, up-regulation of differentiation marker RNA levels, and as much as a 23-fold increase in CPK activity, were observed. After encapsulation and the induction of differentiation, the myoblasts showed a lag phase of ~3 days before an increase in CPK was observed, although the level of CPK activity increased by as much as 63-fold. The myogenic index of the encapsulated cells remained at zero. The rate of human growth hormone secretion was relatively constant throughout the two-week differentiation period, at an average of 7.78 x 10^-2 ng hGH per hour per (mu)g protein, however, human growth hormone secretion was slightly decreased by about twofold during the differentiation of encapsulated myoblasts. In conclusion, the differentiation of myoblasts into myotubes is retarded after encapsulation while the secretion of a recombinant product is slightly reduced. Further studies are necessary to elucidate the cause of this atypical differentiation pattern such that the proliferation and differentiation of the encapsulated myoblasts may be optimized to provide a stable vehicle for gene delivery.

abstract: Thesis

abstract: Master of Science (MS)


title: A NOVEL TREATMENT FOR DIABETIC FOOT ULCERS

subject: doxycycline, diabetic foot ulcers, matrix metalloproteinase

abstract: Tetracycline molecules including doxycycline (DOX), consist of a group of broad-spectrum antibiotics.  In addition, tetracyclines inhibit matrix metalloproteinase (MMPs) that contribute to tissue remodeling, inflammation, angiogenesis and are over-expressed in certain pathologies - such as Alzheimer’s disease, metastasis and diabetic foot ulcers (DFUs). Tetracyclines are hypothesized to inhibit MMPs through the chelation and sequestration of catalytic divalent ions such zinc and calcium. This inhibitory duality may be beneficial in pathologies that are characterized by MMP over-expression and prone to infection, such as DFUs. Compared to oral administration, topical DOX is an attractive route of administration for chronic wound healing as it may minimize the risks: associated antibiotic resistance; is being targeted directly to the wound bed. However, DOX is notoriously unstable in aqueous solution and common topical formulations. Liquid chromatography and mass spectrometry (LCMS) were employed to monitor stability using an in vitro MMP assay and an applicable E. coli anti-bacterial assay was assessed to quantify drug activity.  2 % (w/w) topical DOX demonstrated an acceptable stability 30 day when stored at 4 ºC.  DOX inhibited MMP9 activity with an IC50 value of 48.27 μM. With respect to anti-bacterial activity, using cultured BL21 E.Coli and quantification of drug activity as an expression of colony forming units (CFUs) successfully reproduced the antimicrobial IC50 of doxycycline as 4.3 µM. Transdermal DOX has the potential to improve standard of care for DFUs, quality of life for the patient and reduce costs to the healthcare system.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Tetracyclines comprise of a group of broad-spectrum antibiotics; whose primary mechanism of action is inhibition of protein synthesis through binding of the bacterial ribosome. In addition, tetracyclines inhibit matrix metalloprotease (MMPs), zinc-dependent proteases that contribute to tissue remodeling, angiogenesis and are over-expressed in certain pathophysiologies such as diabetic foot ulcers (DFUs). The antibacterial mechanism of DOX on MMPs is reported and understood, however the inhibition is hypothesized to involve cation chelation. Thus, investigating this interaction is warranted to assist in developing a therapeutic for DFUs. A more logical product would involve direct topical application, such as a stable transdermal formulation of DOX.


title: Observations on the Electrical Activity in the Olfactory Epithelium and Tract of Some Fishes

title: Electrical Activity in the Olfactory System of Some Fishes

contributor:
Kleerekoper, H.
Biology

subject:
electric
olfactory
olfactory epithelium
fish

abstract: In this investigation the electrophysiological response to stimulation of the olfactory epithelium in response to trout scent and some of its chemical components was studied. Recordings were made both from the lamprey nasal sac and the catfish olfactory tract and the various responses described and compared with responses measured by other authors.

abstract: Thesis

abstract: Master of Science (MS)