Medicine and Health Sciences Commons^™

Biomechanical Analysis Of Ligament Modelling Techniques And Femoral Component Malrotation Following Tka, Liam A. Montgomery

Electronic Thesis and Dissertation Repository

Previous studies have demonstrated that satisfaction and revision rates following total knee arthroplasty (TKA) are lower than those of comparable surgeries such as total hip replacements. A leading cause for these revisions is joint instability which may be due to improper ligament balancing or poorly aligned surgical implants. One of the methods used to investigate biomechanical forces and kinematics is computational modelling of the post-operative TKA knee.

A unique knee model was used to investigate the biomechanical and kinematic effects of ligament model complexity, as well as the effects of simulating ligament wrapping versus ignoring ligament wrapping. We then used …

Effect Of Levodopa On Eeg Connectivity In Parkinson's Patients, Sepehr Torab Parhiz

Electronic Thesis and Dissertation Repository

Levodopa is a dopamine replacement medication administered to patients with Parkinson’s disease (PD) to alleviate their motor symptoms. However, its long-term use can cause adverse side effects, including involuntary motor movements. We studied 16 PD patients before and after taking Levodopa based on resting-state electroencephalography (EEG) recordings to determine how Levodopa affects the functional connectivity of their brain networks. We used several metrics from graph theory, in particular the minimum spanning tree (MST) metric, and analyzed how they change after subjects take Levodopa. We observed significant changes in the lower alpha band toward a more path-like and less globally efficient …

4dct Analysis Of In-Vivo Carpal Kinematics During Fem, Manisha R. Mistry

Electronic Thesis and Dissertation Repository

A consensus, detailed understanding of carpal kinematics remains elusive. 4-dimensional CT (4DCT) is a validated modality capable of accurately studying in-vivokinematic motion. The objective of this work is to quantify normal, in-vivo kinematic motion of the carpus through a flexion-extension arc of motion using 4DCT. Ten healthy, un-injured volunteers underwent a 4DCT scanning protocol through a complete arc of flexion-extension motion. Kinematic changes in motion were quantified using helical axis motion data for each carpal bone. Helical axes were compared between bones and statistical analysis performed using repeated-measures ANOVA to identify difference in kinematic motion between bones (p<0.05). The carpus can be divided into four main kinematic blocks: the distal carpal block, the proximal carpal block and individual scaphoid and trapezial blocks. This work supports an additional segmentation of the trapezium from the distal carpal row, which suggests some modulation between the scaphoid and distal carpal row.

Development Of A Low-Cost Algometer, Thomas D. Naish, Ana Luisa Trejos, Dave M. Walton

Undergraduate Student Research Internships Conference

Many people suffer from chronic pain, the reasons for which are not always well understood. Algometers are instruments that can help clinicians understand the nature of pain by determining the force at which pain becomes noticeable or unbearable. Algometers can also be used to determine the effects that external influences can have on pain tolerance in healthy people.

The goal of this project was to develop an algometer that can measure the normal range of pain thresholds and tolerances of most patients, which ranges up to 35 lbs. Also, the result needed to be accurate to about 1% and made …

Liam Briggs 2021 Usri - Audio Testing Device, Liam Briggs

Undergraduate Student Research Internships Conference

Portable and cost-effective hearing testing device with a UI that can be accessed on a remote web server.

Frequency Dependent Diffusion Kurtosis Measurement In The Human Brain With Oscillating Gradients, Kevin B. Borsos

Electronic Thesis and Dissertation Repository

Oscillating gradient spin-echo (OGSE) is an implementation of diffusion MRI that enables shorter effective diffusion times than the conventional pulse gradient spin-echo (PGSE) by periodically modulating the diffusion gradient. Measurements of the diffusion kurtosis, which reflects the degree of restricted diffusion, have previously been prohibited with OGSE due to technical limitations of clinical gradient systems. This thesis presents a novel oscillating gradient waveform that enables the measurement of kurtosis using OGSE without requiring advanced gradient hardware. Decreases of kurtosis are observed in OGSE acquisitions of healthy human subjects relative to PGSE, demonstrating the dependence of the kurtosis on oscillation frequency. …

Rapid Microscopic Fractional Anisotropy Imaging Via An Optimized Linear Regression Formulation., N J J Arezza, D H Y Tse, C A Baron

Medical Biophysics Publications

Water diffusion anisotropy in the human brain is affected by disease, trauma, and development. Microscopic fractional anisotropy (μFA) is a diffusion MRI (dMRI) metric that can quantify water diffusion anisotropy independent of neuron fiber orientation dispersion. However, there are several different techniques to estimate μFA and few have demonstrated full brain imaging capabilities within clinically viable scan times and resolutions. Here, we present an optimized spherical tensor encoding (STE) technique to acquire μFA directly from the 2nd order cumulant expansion of the powder averaged dMRI signal obtained from direct linear regression (i.e. diffusion kurtosis) which requires fewer powder-averaged signals than …

Catechol-Containing Copolymers As An Active Ingredient For Denture Adhesives, Vincent Ying Wun Kong

Electronic Thesis and Dissertation Repository

Moisture inside the mouth adds challenge to making denture adhesives formulations. Some formulations have zinc to enhance adhesion on wet skin despite knowing the health hazards. Inspired by mussel foot proteins’ catechol unit’s strong underwater adhesion, nine catechol-containing copolymers (P1A-P3C) were synthesized by free radical polymerization of 3,4-dimethoxystyrene (3,4- DMS) with different styrene derivatives followed by deprotection. P1A-P3C were used to make Fn(P)-C-PBS denture adhesive formulations which had suitable shear stresses around ≥ 5 kPa satisfying ISO 10873. In-situ NMR studies of free radical polymerization of 3,4 - DMS and styrene derivatives allowed computation of their reactivity ratios showing all …

In Vitro Analyses Of The Contributions Of The Hip Capsule To Joint Biomechanics, Emma Donnelly

Electronic Thesis and Dissertation Repository

Optimal management of the hip capsule during arthroscopic surgery has not been established. The impact of incisions made to the capsule during minimally invasive procedures on joint biomechanics, and whether repair provides any benefit, continue to be debated. The effectiveness of capsular repair to restore native kinematics may be insufficient. Therefore, a better understanding of joint behavior during various capsule conditions is needed. A new robotic system was used to analyze the effect of progressive capsulotomy incision and repairs on the behavior of a normal hip within range of motion (ROM) limits with respect to the intact joint. Complete repairs …

Micro-Ct Of The Human Ossicular Chain: Statistical Shape Modeling And Implications For Otologic Surgery, Western University, London Health Sciences Centre

Electrical and Computer Engineering Publications

The ossicular chain is a middle ear structure consisting of the small incus, malleus and stapes bones, which transmit tympanic membrane vibrations caused by sound to the inner ear. Despite being shown to be highly variable in shape, there are very few morphological studies of the ossicles. The objective of this study was to use a large sample of cadaveric ossicles to create a set of three-dimensional models and study their statistical variance. Thirty-three cadaveric temporal bone samples were scanned using micro-computed tomography (μCT) and segmented. Statistical shape models (SSMs) were then made for each ossicle to demonstrate the divergence …