Engineering Commons^™

Resting-State Functional Network Disruptions In A Rodent Model Of Mesial Temporal Lobe Epilepsy (Tle), Ravnoor Singh Gill

Electronic Thesis and Dissertation Repository

Mesial temporal lobe epilepsy (TLE) is the most common form of drug-refractory epilepsy. The clinical application of non-invasively mapped networks using resting-state functional magnetic resonance imaging (rsfMRI) in humans has been rather limited due to heterogeneous (varying etiology, drugs, onset, latent period, etc.) patient groups. We employed a pharmacological (kainic acid) rodent model of TLE to measure the extent of functional network disruptions using rsfMRI, and study selected behaviors and olfactory to hippocampus transmission. Graph theoretical network modelling and analysis revealed significant increase in functional connectivity connectivity to the temporal lobe (hippocampus) in epileptic-rats compared to controls in the limbic …

Production And Applications Of Formaldehyde-Free Phenolic Resins Using 5-Hydroxymethylfurfural Derived From Glucose In-Situ, Yongsheng Zhang

Electronic Thesis and Dissertation Repository

The phenol-formaldehyde (PF) resin manufacturing industry is facing a growing challenge with respect to concerns over human health, due to the use of carcinogenic formaldehyde and sustainability due to the use of petroleum-based phenol in PF resin manufacture. Glucose and its derivative, 5-hydroxymethylfurfural (5-HMF), have proven to be potential substitutes for formaldehyde in the synthesis of phenolic novolac resins.

This thesis investigated a number of glucose and 5-HMF resin systems including the curing of phenol-glucose novolac resin (PG) with a bis-phenol-A type epoxy. The curing process was modeled according to the Sestak-Berggren equation (S, B) using Málek methods. This was …

Advances In Image Acquisition And Filtering For Mri Neuroimaging At 7 Tesla, Andrew T. Curtis

Electronic Thesis and Dissertation Repository

Performing magnetic resonance imaging at high magnetic field strength promises many improvements over low fields that are of direct benefit in functional neuroimaging. This includes the possibility of improved signal-to-noise levels, and increased BOLD functional contrast and spatial specificity. However, human MRI at 7T and above suffers from unique engineering challenges that limit the achievable gains. In this thesis, three technological developments are introduced, all of which address separate issues associated with functional magnetic resonance neuroimaging at very high magnetic field strengths.

First, the image homogeneity problem is addressed by investigating methods of RF shimming — modifying the excitation portion …

The Effects Of Oar-Shaft Stiffness And Length On Rowing Biomechanics, Brock Laschowski

Electronic Thesis and Dissertation Repository

This work investigates the effects of oar-shaft stiffness and length on rowing biomechanics. The mechanical properties of the oar-shafts were examined using an end-loaded cantilever system, and theoretical relations were proposed between the mechanics of the oar-shafts and rowing performance. On-water experiments were subsequently conducted and rowing biomechanics measured via the PowerLine Rowing Instrumentation System. The PowerLine system measures force and oar angle on the oarlock, as well as proper boat acceleration. The convergent validity and test-retest reliability of the PowerLine force measurements were determined prior to the on-water experiments. Thereafter, rowers were tested over a set distance using oar-shafts …

Human Metaphase Chromosome Analysis Using Image Processing, Akila M.S Subasinghe Arachchige

Electronic Thesis and Dissertation Repository

Development of an effective human metaphase chromosome analysis algorithm can optimize expert time usage by increasing the efficiency of many clinical diagnosis processes. Although many methods exist in the literature, they are only applicable for limited morphological variations and are specific to the staining method used during cell preparation. They are also highly influenced by irregular chromosome boundaries as well as the presence of artifacts such as premature sister chromatid separation.

Therefore an algorithm is proposed in this research which can operate with any morphological variation of the chromosome across images from multiple staining methods. The proposed algorithm is capable …

Plasmonic Optical Sensors: Performance Analysis And Engineering Towards Biosensing, Peipei Jia

Electronic Thesis and Dissertation Repository

Surface plasmon resonance (SPR) sensing for quantitative analysis of chemical reactions and biological interactions has become one of the most promising applications of plasmonics. This thesis focuses on performance analysis for plasmonic sensors and implementation of plamonic optical sensors with novel nanofabrication techniques.

A universal performance analysis model is established for general two-dimensional plasmonic sensors. This model is based on the fundamental facts of surface plasmon theory. The sensitivity only depends on excitation light wavelength as well as dielectric properties of metal and dielectrics. The expression involves no structure-specified parameters, which validates this formula in broad cases of periodic, quasiperiodic …

Economic Evaluation Of Potential Applications Of Gene Expression Profiling In Clinical Oncology, Malek Hannouf

Electronic Thesis and Dissertation Repository

Histopathological analysis of tumor is currently the main tool used to guide cancer management. Gene expression profiling may provide additional valuable information for both classification and prognostication of individual tumors. A number of gene expression profiling assays have been developed recently to inform therapy decisions in women with early stage breast cancer and help identify the primary tumor site in patients with metastatic cancer of unknown primary. The impact of these assays on health and economic outcomes, if introduced into general practice, has not been determined. I aimed to conduct an economic evaluation of regulatory-approved gene expression profiling assays for …

Oriented Collagen And Applications Of Waveguide Evanescent Field Scattering (Wefs) Microscopy, Qamrun Nahar

Electronic Thesis and Dissertation Repository

In this thesis, Waveguide Evanescent Field Scattering (WEFS) microscopy is developed as a non-invasive, label-free live cell imaging technique. This new high-contrast imaging can be employed to study the first hundred nanometers from the surface as it utilizes the evanescent field of a waveguide as the illumination source. Previously, waveguide evanescent field fluorescence (WEFF) microscopy was developed as a fluorescence imaging technique comparable to the total internal reflection fluorescent (TIRF) microscopy. Both the WEFF and WEFS technique utilizes the same fundamental concepts except in WEFS microscopy imaging is accomplished without the application of any fluorescent labeling. In this work, bacterial …

The Effects Of Ocean Acidification And Eutrophication On The Growth, Lipid Composition And Toxicity Of The Marine Raphidophyte Heterosigma Akashiwo., Julia Rose Matheson

Electronic Thesis and Dissertation Repository

Anthropogenic forcing, such as ocean acidification caused by rising carbon dioxide emissions, and eutrophication due to increased nutrient loadings in run-off, are causing major changes to the biogeochemistry of the oceans. As a consequence, coastal phytoplankton are susceptible to altered biogeochemical environments. This study examined the effect of a lower pH and increased levels of nutrients on the common coastal harmful alga, Heterosigma akashiwo. Growth rates, maximal cell yields, neutral lipid accumulation and toxicity of cells grown under various pH and nutrients regimes were measured. H. akashiwo growth was near maximal when grown at lower pH levels. There was …

Effects Of Biodiesel Concentration On Microbial Deterioration Of Polyethylene In A Simulated Fuel Storage Tank, Juan Manuel Restrepo-Florez

Electronic Thesis and Dissertation Repository

In this study a simulated fuel storage tank was used to investigate the effect of biodiesel concentration on biodegradation of polyethylene. This research is relevant in the field of fuel storage. The simulated storage system consisted of a number of identical conical flasks. Each flask was comprised of two layers, an upper one consisting of a fuel blend of diesel with biodiesel in concentrations ranging from 0 to 100% of biodiesel and the bottom layer containing an aqueous mineral media inoculated with a community obtained from a real fuel storage facility. Polyethylene slabs cut to a specific size were immersed …

A Hybrid Visual Control Scheme To Assist The Visually Impaired With Guided Reaching Tasks, Duane Jacques

Electronic Thesis and Dissertation Repository

In recent years, numerous researchers have been working towards adapting technology developed for robotic control to use in the creation of high-technology assistive devices for the visually impaired. These types of devices have been proven to help visually impaired people live with a greater degree of confidence and independence. However, most prior work has focused primarily on a single problem from mobile robotics, namely navigation in an unknown environment. In this work we address the issue of the design and performance of an assistive device application to aid the visually-impaired with a guided reaching task. The device follows an eye-in-hand, …

Fabricating Cost-Effective Nanostructures For Biomedical Applications, Erden Ertorer

Electronic Thesis and Dissertation Repository

In this thesis we described inexpensive alternatives to fabricate nanostructures on planar substrates and provided example applications to discuss the efficiency of fabricated nanostructures.

The first method we described is forming large area systematically changing multi-shape nanoscale structures on a chip by laser interference lithography. We analyzed the fabricated structures at different substrate positions with respect to exposure time, exposure angle and associated light intensity profile. We presented experimental details related to the fabrication of symmetric and biaxial periodic nanostructures on photoresist, silicon surfaces, and ion-milled glass substrates. Behavior of osteoblasts and osteoclasts on the nanostructures was investigated. These results …

Effect Of Plant Hormones On The Production Of Biomass And Lipid In Microalgae, Malihe Mehdizadeh Allaf

Electronic Thesis and Dissertation Repository

Limited fossil fuel reserves, increasing demand for energy in all parts of the world are some driving forces to look for new sources of transportation fuels. Among different options available, microalgae are currently attracting wide interests as an alternative and renewable fuel source.

Microalgae are single cell photosynthetic organisms that are known for rapid growth and high energy content and as a part of photosynthesis; they produce oil that can be used as a feedstock for biodiesel production. Some algae strains could contain lipid up to 80% of the dry biomass. The amount of lipid production is in direct relation …

Photocalytic Degradation Of Malic Acid Under Thin Coated Tio2, Vanessa Silveira Rodgher

Electronic Thesis and Dissertation Repository

Opaque fluids have a limited irradiation transmission. Thus, their decontamination employing near UV irradiation poses significant technical challenges. In the present study, a thin UV-transparent/waterproof glue layer coated with a 1.5 wt% of TiO₂ and a new PhotoReactor Cell were implemented. TiO₂ irradiation in the PhotoReactor Cell was effected on the TiO₂ particle side, not directly in contact with the fluid, allowing the postulation of an “h⁺” site mobility mechanism on photocatalysis.

Photocatalytic degradation experiments with malic and malonic acid in water at 10, 20, 30 and 40 ppm showed the complete degradation of malic …

The Near Wake Of A European Starling, Adam J. Kirchhefer

Electronic Thesis and Dissertation Repository

The wake of a freely flying European starling (Sturnus vulgaris) was measured using high speed, time-resolved, particle image velocimetry, simultaneously with high speed cameras which imaged the bird. These measurements have been used to generate vector maps in the near wake that can be associated with the bird’s location and wing configuration. A kinematic analysis has been performed on select sequences of measurements to characterize the motion of the bird, as well as provide a point of comparison between the bird of the present study and other birds or flapping wings. Time series of measurements have been expressed …

Resting-State Connectivity Identifies Distinct Functional Networks In Macaque Cingulate Cortex., R Matthew Hutchison, Thilo Womelsdorf, Joseph S Gati, L Stan Leung, Ravi S Menon, Stefan Everling

Physiology and Pharmacology Publications

Subregions of the cingulate cortex represent prominent intersections in the structural networks of the primate brain. The relevance of the cingulate to the structure and dynamics of large-scale networks ultimately requires a link to functional connectivity. Here, we map fine-grained functional connectivity across the complete extent of the macaque (Macaca fascicularis) cingulate cortex and delineate subdivisions pertaining to distinct identifiable networks. In particular, we identified 4 primary networks representing the functional spectrum of the cingulate: somatomotor, attention-orienting, executive, and limbic. The cingulate nodes of these networks originated from separable subfields along the rostral-to-caudal axis and were characterized by positive and …

A Method To Measure The Detective Quantum Efficiency Of Radiographic Systems In Clinical Setting, Michael C. Mcdonald

Electronic Thesis and Dissertation Repository

The risks associated with exposure to radiation make it critical that digital imaging systems give the best possible images for a given dose to the patient. The DQE is the most widely accepted measure of performance and dose efficiency for digital radiography systems, however it is not commonly measured in a clinical environment as part of routine quality assurance. The primary reason for this is that the data provided to the user by clinical systems has typically undergone image processing and therefore may have a non-linear characteristic response. This is a problem because the Fourier metrics of the DQE require …

Exploring Bacterial Nanowires: From Properties To Functions And Implications, Kar Man Leung

Electronic Thesis and Dissertation Repository

The discovery of electrically conductive bacterial nanowires from a broad range of microbes provides completely new insights into microbial physiology. Shewanella oneidensis strain MR-1, a dissimilatory metal-reducing bacterium, produces extracellular bacterial nanowires up to tens of micrometers long, with a lateral dimension of ~10 nm. The Shewanella bacterial nanowires are efficient electrical conductors as revealed by scanning probe techniques such as CP-AFM and STM.

Direct electrical transport measurements along Shewanella nanowires reveal a measured nanowire resistivity on the order of 1 Ω∙cm. With electron transport rates up to 10⁹/s at 100 mV, bacterial nanowires can serve as a …

Use Of Imaging Biomarkers To Assess Perfusion And Glucose Metabolism In The Skeletal Muscle Of Dystrophic Mice, Nabeel Ahmad, Ian Welch, Robert Grange, Jennifer Hadway, Savita Dhanvantari, David Hill, Ting-Yim Lee, Lisa M Hoffman

Robarts Imaging Publications

BACKGROUND: Duchenne muscular dystrophy (DMD) is a severe neuromuscular disease that affects 1 in 3500 boys. The disease is characterized by progressive muscle degeneration that results from mutations in or loss of the cytoskeletal protein, dystrophin, from the glycoprotein membrane complex, thus increasing the susceptibility of contractile muscle to injury. To date, disease progression is typically assessed using invasive techniques such as muscle biopsies, and while there are recent reports of the use of magnetic resonance, ultrasound and optical imaging technologies to address the issue of disease progression and monitoring therapeutic intervention in dystrophic mice, our study aims to validate …