Engineering Commons^™

Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed

Electronic Thesis and Dissertation Repository

The fast diminishing of fossil fuels in the near future, as well as the global warming caused by increasing greenhouse gases have motivated the urgent quest to develop advanced materials as cost-effective photoanodes for solar light harvesting and many other photocatalytic applications. Recently, titania nanotube arrays (TNTAs) fabricated by anodization process has attracted great interest due to their excellent properties such as: high surface area, vertically oriented, highly organized, one-dimensional, nanotubular structure, photoactivity, chemical stability and biocompatibility. This unique combination of excellent properties makes TNTAs an excellent photoanode for solar light harvesting. However, the relatively wide band gap energy of …

Optical Fibre-Based Force Sensing Needle Driver For Minimally Invasive Surgery, Pouya Soltani Zarrin

Electronic Thesis and Dissertation Repository

Minimally invasive surgery has been limited from its inception by insufficient haptic feedback to surgeons. The loss of haptic information threatens patients safety and results in longer operation times. To address this problem, various force sensing systems have been developed to provide information about tool–tissue interaction forces. However, the provided results for axial and grasping forces have been inaccurate in most of these studies due to considerable amount of error and uncertainty in their force acquisition method. Furthermore, sterilizability of the sensorized instruments plays a pivotal role in accurate measurement of forces inside a patient's body. Therefore, the objective of …

Syngenic Adipose-Derived Stem/Stromal Cells Delivered In Decellularized Adipose Tissue Scaffolds Enhance In Vivo Tissue Regeneration Through Host Cell Recruitment, Kevin P. Robb

Electronic Thesis and Dissertation Repository

Decellularized adipose tissue (DAT) represents a promising adipogenic bioscaffold for applications in soft tissue augmentation or reconstruction. With the goal of investigating the role of syngeneic donor adipose-derived stem/stromal cells (ASCs) and host myeloid cells during in vivo adipose tissue regeneration, transgenic reporter mouse strains were used to track these cell populations within ASC-seeded and unseeded DAT scaffolds. Donor ASCs were obtained from dsRed transgenic mice. These cells were shown to express characteristic cell surface markers, and multilineage differentiation capacity was confirmed. To facilitate cell tracking, DAT scaffolds were subcutaneously implanted into MacGreen mice in which myeloid cells express enhanced …

Design, Implementation And Control Of A Robotic Platform For Post-Stroke Upper- And Lower-Limb Rehabilitation, Vahid Mehrabi

Electronic Thesis and Dissertation Repository

Stroke is the primary cause of permanent disabilities worldwide. Hemiparesis and hemiplegia (the most common consequences of stroke) are the decreases in motor-functionality of the brain on one side of the body which will affect the daily life activities of the patient. There are several challenges with the current state of delivering rehabilitation services such as limitations on the number of the clinics, financial resources needed for providing rehabilitation, associated costs of transportation, and human resources. To overcome the issues related to conventional ways of delivering therapy, different robotic systems have been developed to benefit healthcare systems and patient with …

A 3d Us Guidance System For Permanent Breast Seed Implantation: Development And Validation, Justin Michael

Electronic Thesis and Dissertation Repository

Permanent breast seed implantation (PBSI) is a promising breast radiotherapy technique that suffers from operator dependence. We propose and have developed an intraoperative 3D ultrasound (US) guidance system for PBSI.

A tracking arm mounted to a 3D US scanner registers a needle template to the image. Images were validated for linear and volumetric accuracy, and image quality in a volunteer. The tracking arm was calibrated, and the 3D image registered to the scanner. Tracked and imaged needle positions were compared to assess accuracy and a patient-specific phantom procedure guided with the system.

Median/mean linear and volumetric error was ±1.1% and …

Design And Evaluation Of Neurosurgical Training Simulator, Trinette L. Wright

Electronic Thesis and Dissertation Repository

Surgical simulators are becoming more important in surgical training. Consumer smartphone technology has improved to allow deployment of VR applications and are now being targeted for medical training simulators. A surgical simulator has been designed using a smartphone, Google cardboard 3D glasses, and the Leap Motion (LM) hand controller. Two expert and 16 novice users were tasked with completing the same pointing tasks using both the LM and the medical simulator NeuroTouch. The novice users had an accuracy of 0.2717 bits (SD 0.3899) and the experts had an accuracy of 0.0925 bits (SD 0.1210) while using the NeuroTouch. Novices and …

Exploiting Temporal Image Information In Minimally Invasive Surgery, Jonathan Mcleod

Electronic Thesis and Dissertation Repository

Minimally invasive procedures rely on medical imaging instead of the surgeons direct vision. While preoperative images can be used for surgical planning and navigation, once the surgeon arrives at the target site real-time intraoperative imaging is needed. However, acquiring and interpreting these images can be challenging and much of the rich temporal information present in these images is not visible. The goal of this thesis is to improve image guidance for minimally invasive surgery in two main areas. First, by showing how high-quality ultrasound video can be obtained by integrating an ultrasound transducer directly into delivery devices for beating heart …

Development Of An Active Finger Motion Simulator: With In-Vitro Assessments Of Tendon Loads And Joint Kinematics, Mohammad Haddara

Electronic Thesis and Dissertation Repository

Musculoskeletal injuries of the finger far outnumber those of other joints, and while in-vitro motion simulators are useful for studying joint biomechanics and evaluating surgical repairs, considerably less simulator development has been reported for the finger compared to other joints. Replication of active musculoskeletal movement during in-vitro testing has been shown to be more representative of in-vivo motion patterns, and closed-loop motion controllers are the current state-of-the-art for in-vitro kinematics studies. However, an in-vitro motion simulator with closed-loop tendon load control and simultaneous tendon excursion control has not yet been reported for the finger. This thesis outlines the design and …

Functional Design And Analysis Of A Linked Shoulder Prosthesis, Emily West

Electronic Thesis and Dissertation Repository

Persistent shoulder instability following joint arthroplasty remains a concern with mixed outcomes following clinical and surgical intervention. Thus, a linked universal joint implant was developed and functionally analyzed. A virtual model of the linked implant was developed and implanted in a 3D bony specimen to measure the available circumduction range of motion. Stresses in the implant were estimated using finite element analysis based on joint loads during activities of daily life. The glenoid fixation stress was evaluated using finite element analysis.

The implant was capable of restoring normal range of motion, and withstanding expected joint loads without yield or fatigue …

A Patient-Specific Cardiac Phantom For Training And Pre-Procedure Surgical Planning, Justin Laing

Electronic Thesis and Dissertation Repository

Minimally invasive cardiac procedures requiring a transseptal puncture are becoming increasingly common. For cases of complex or diseased anatomy, clinicians may benefit from using a patient-specific cardiac phantom for training, surgical planning, and the validation of devices or techniques.

An imaging compatible cardiac phantom was developed to simulate a MitraClip ® procedure. The phantom contained a patient-specific cardiac model manufactured using tissue mimicking materials.

To evaluate accuracy, the patient-specific model was imaged using CT, segmented, and the resulting point cloud data set was compared using absolute distance to the original patient data. The phantom was validated using a MitraClip ® …

Influence Of Scapular Notching On Contact Mechanics And Simulator Wear Of Reverse Total Shoulder Arthroplasty Implants, Michael William Griffiths

Electronic Thesis and Dissertation Repository

Scapular notching is a common complication of reverse total shoulder arthroplasty (RTSA) wherein the predominant focus of current literature has been on changes in osseous anatomy. However, the implications on RTSA performance from the damaged humeral cup is largely unknown. Therefore the present work describes the effects of the initiation and propagation of the humeral cup defect resulting from scapular notching through the use of finite element modeling and wear simulation, in order to assess changes in RTSA contact mechanics and tribological properties. A significant decrease in articular contact area and increase in maximum contact stress values was found for …

Experimental Measurements Of Far Field Cough Airflows Produced By Healthy And Influenza- Infected Human Subjects, Ahmed Faraj Alarbi Mohamed

Electronic Thesis and Dissertation Repository

The present work details an experimental study of the cough airflow fields produced by subjects infected with influenza and when they are convalescent, together with data from healthy cohorts. The PIV and HWA measurements were taken far downstream at 1 m from the source within a cough chamber, along with droplet sampling at two different locations and nasal swabs from the sick subjects. The measured data over different seasons were used to evaluate and compare the results from sick, convalescent and healthy subjects. Although a total of 8 sick participants from winter 2014 and 2017 yielded positive nasal swab analysis, …

A Biomechanical Investigation Of Load Sharing At The Distal Forearm, Martine E. Mcgregor

Electronic Thesis and Dissertation Repository

Loading at the distal forearm has been previously examined under static loads, however there remains no consensus on how loading is affected by active wrist and forearm motion. This work examines load magnitudes and load sharing at the distal radius and ulna during of active wrist and forearm motion. Two instrumented implants were designed to measure in vitro loading in cadaveric specimen. The implants were evaluated and found reliable for use in further biomechanical studies. An in vitro study investigated the effect of joint angle and direction of joint motion on loads in the distal radius and ulna during active …

Evaluating And Improving Cochlear Length Measurements On Clinical Computed Tomography Images, John E. Iyaniwura

Electronic Thesis and Dissertation Repository

Cochlear implants provide the sensation of sound to deaf individuals. An accurate estimate of cochlear duct length (CDL) is required for pre-operative implant electrode selection and can be obtained from clinical computed tomography (CT) by measuring the “A-value”.

The objectives of this work were to estimate the accuracy and variability in manual A-value measurements, and to automate measurements.

Four specialists repeatedly measured the A-value on clinical CT images from which the inter- and intra-observer variability were calculated. Accuracy was assessed by comparison to measurements on higher resolution micro-CT images. Motivated by this study, software was developed to automate the A-value …

Force Sensing Surgical Grasper With Folding Capacitive Sensor, Dave Bp Tripp

Electronic Thesis and Dissertation Repository

Minimally-invasive surgery (MIS) has brought many benefits to the operating room, however, MIS procedures result in an absence of force feedback, and surgeons cannot as accurately feel the tissue they are working on, or the forces that they are applying. One of the barriers to introducing MIS instruments with force feedback systems is the high cost of manufacturing and assembly. Instruments must also be sterilized before every use, a process that can destroy embedded sensing systems. An instrument that can be disposed of after a single use and produced in bulk at a low cost is desirable. Printed circuit micro-electro-mechanical …

A Biomechanical Approach For Real-Time Tracking Of Lung Tumors During External Beam Radiation Therapy (Ebrt), Elham Karami

Electronic Thesis and Dissertation Repository

Lung cancer is the most common cause of cancer related death in both men and women. Radiation therapy is widely used for lung cancer treatment. However, this method can be challenging due to respiratory motion. Motion modeling is a popular method for respiratory motion compensation, while biomechanics-based motion models are believed to be more robust and accurate as they are based on the physics of motion. In this study, we aim to develop a biomechanics-based lung tumor tracking algorithm which can be used during External Beam Radiation Therapy (EBRT). An accelerated lung biomechanical model can be used during EBRT only …

The Effect Of Radial And Ulnar Length Change On Distal Forearm Loading, Ahaoiza D. Isa

Electronic Thesis and Dissertation Repository

The effect of distal radial and ulnar length change on forearm bone loading is not well understood during simulated dynamic wrist loading. This thesis presents two studies which investigate the effect of these length changes on distal forearm loading under simulated dynamic wrist motion. The first study investigates the effect of radial length change on axial loading at the distal radius and ulna and relationship between ulnar variance and distal forearm loading. The complex variation in axial loads in the distal radius and during length change and dynamic wrist motion were studied and discussed. There was no correlation between native …

The Design, Fabrication, And Characterization Of Nanoparticle-Protein Interactions For Theranostic Applications, Wai Hei Tse

Electronic Thesis and Dissertation Repository

Theranostics, a combination of therapeutics and diagnostics, spans a spectrum of research areas to provide new opportunities in developing new healthcare technologies and medicine at affordable prices. Through employing a personalized medicine approach, biotechnology can be tailored to the needs of an individual. Applications of theranostics include drug delivery carriers capable of sustained drug release and targeted delivery, biosensors with high sensitivity and selectivity, and diagnostic relevant entities that can be incorporated into the former technologies. Nanotechnology provides a suitable foundation for theranostics to build upon due to material-based properties; magnetism, biocompatibility, and quantum effects to name a few. Purpose …

Nanostructured Biosensor For Tear Glucose Detection Based On Bioluminescence Resonance Energy Transfer (Bret) Mechanism., Denghuang Zhan

Electronic Thesis and Dissertation Repository

Bioluminescence Resonance Energy Transfer (BRET), a sensitive, non-destructive and self-illuminated method, has been now commonly used to test protein interactions. Here, we describe a BRET sensor for non-invasively detecting glucose molecules. The sensor is made by the bioconjugation of quantum dots and recombinant protein. The recombinant protein contains the bacterial glucose binding protein (GBP) and a bioluminescent protein, Renilla luciferase (Rluc), used as the donor with the emission peak at 470 nm, which is able to excite the acceptor of BRET sensor made of cadmium tellurium quantum dots ( CdTe QDs) with the emission peak at 570 nm. The distance …

Genetic Engineering Studies Of Escherichia Coli And Microalgae For Expression Of Hydrolytic Enzymes And Development Of High Throughput Screening Technique, Shreyas S. Yedahalli

Electronic Thesis and Dissertation Repository

The field of biochemical engineering has made substantial progress through major advances in genetic and metabolic engineering with applications in various sectors such as energy, food science, pharmaceuticals, etc. The hosts used for this work are constantly broadening. A host particularly important for energy applications are microalgae. The potential to enhance microalgae genetically for energy applications is not well explored and was therefore investigated in this thesis. Non-photosynthetic micro-organisms and photosynthetic microalgae offer a potential approach to enhance sustainable biochemical production. In this study expression vectors for Escherichia coli (E. coli) and Chlorella vulgaris (C. vulgaris) …

Design And Evaluation Of A Contact-Free Interface For Minimally Invasive Robotics Assisted Surgery, Cameron Dawson

Electronic Thesis and Dissertation Repository

Robotic-assisted minimally invasive surgery (RAMIS) is becoming increasingly more common for many surgical procedures. These minimally invasive techniques offer the benefit of reduced patient recovery time, mortality and scarring compared to traditional open surgery. Teleoperated procedures have the added advantage of increased visualization, and enhanced accuracy for the surgeon through tremor filtering and scaling down hand motions. There are however still limitations in these techniques preventing the widespread growth of the technology. In RAMIS, the surgeon is limited in their movement by the operating console or master device, and the cost of robotic surgery is often too high to justify …

Real-Time Membrane Puncture Detection Using Force Sensors For Micro-Injections In Phantoms, Szymon Kowal

Electronic Thesis and Dissertation Repository

Micro-manipulators provide tools for researchers to improve workflow in common preclinical and clinical applications. Following drug delivery injections where drugs did not reach their target will squander research time, experimental animals and other resources. An ultrasound-guided robot developed at Robarts Research Institute was revised to implement closed-loop force feedback to compensate for tissue deformation during micro-interventions. Force sensors can detect puncture events as the needle penetrates tissue membranes, thereby reducing damage to surrounding tissues by preventing the needle from overshooting its target. Changing the angle of injection determined that the range of detectable forces during injections into tissue-mimicking phantoms suggests …

Contributions Of Continuous Max-Flow Theory To Medical Image Processing, John Sh Baxter

Electronic Thesis and Dissertation Repository

Discrete graph cuts and continuous max-flow theory have created a paradigm shift in many areas of medical image processing. As previous methods limited themselves to analytically solvable optimization problems or guaranteed only local optimizability to increasingly complex and non-convex functionals, current methods based now rely on describing an optimization problem in a series of general yet simple functionals with a global, but non-analytic, solution algorithms. This has been increasingly spurred on by the availability of these general-purpose algorithms in an open-source context. Thus, graph-cuts and max-flow have changed every aspect of medical image processing from reconstruction to enhancement to segmentation …

Design And Validation Of Delivery Systems For Galectin-3 For Skin Healing Applications, Karrington A. Mcleod

Electronic Thesis and Dissertation Repository

Chronic wounds present a significant burden to patients, causing pain, impairing limb function, and often resulting in the need for amputation. Treatment of chronic dermal wounds is challenging, with current therapies showing limited efficacy in clinical trials. As galectin-3 has been implicated in several wound healing processes, its efficacy as a therapeutic in skin healing was investigated in this study. An electrospun gelatin scaffold loaded with galectin-3 was developed as a delivery system. The influence of human recombinant galectin-3 in skin healing, when delivered topically and using an electrospun scaffold, was then investigated in wild type and diabetic mice. Electrospun …

Assessment Of The Non-Linear Stress-Strain Characteristics Of Poly (Vinyl Alcohol) Cryogel, Mojdeh Zakeri

Electronic Thesis and Dissertation Repository

Creation of tissue-mimicking constructs is of great importance in the field of biomedical engineering. Poly (vinyl Alcohol) (PVA) is a biomaterial capable of simulating a wide range of geometries and mechanical properties of biological tissues. It is nontoxic, biocompatible, and easy to produce. PVA can be physically crosslinked by repeated cycles of freezing and thawing. The final product of this process is called PVA cryogel (PVA-C). The mechanical properties of PVA-C can be accurately controlled by changing PVA molecular weight, PVA concentration, and number and duration of freeze/thaw cycles (FTC). In this study, the stress-strain behavior of PVA cryogel was …

Investigation Of Chitosan-Based Hydrogels As A Cell Delivery Platform For Adipose-Derived Stem/Stromal Cell Transplantation To Promote Angiogenesis In Ischemic Tissues, Jobanpreet Singh Dhillon

Electronic Thesis and Dissertation Repository

Stem cell transplantation is under investigation to stimulate angiogenesis in patients with peripheral artery disease. To develop a cell-delivery platform that enhances cell retention and function post-transplantation, the response of human adipose-derived stem/stromal cells (ASCs) encapsulated within N-methacrylate glycol chitosan (MGC) hydrogels with or without integrin-binding RGD or IKVAV motifs was explored. ASC viability was enhanced in the MGC and MGC-RGD hydrogels relative to the MGC-IKVAV group under hypoxic (2% O­₂) culture conditions, with cell spreading and higher metabolic activity noted in MGC-RGD at 14 days. Analysis of angiogenic gene expression revealed similar patterns between all hydrogel …

Computer-Assisted Characterization Of Prostate Cancer On Magnetic Resonance Imaging, Derek J. Soetemans

Electronic Thesis and Dissertation Repository

Prostate cancer (PCa) is one of the most prevalent cancers among men. Early diagnosis can improve survival and reduce treatment costs. Current inter-radiologist variability for detection of PCa is high. The use of multi-parametric magnetic resonance imaging (mpMRI) with machine learning algorithms has been investigated both for improving PCa detection and for PCa diagnosis. Widespread clinical implementation of computer-assisted PCa lesion characterization remains elusive; critically needed is a model that is validated against a histologic reference standard that is densely sampled in an unbiased fashion. We address this using our technique for highly accurate fusion of mpMRI with whole-mount …

Histological Quantification In Temporal Lobe Epilepsy, Charlotte Anne Blinston

Electronic Thesis and Dissertation Repository

Approximately 30 percent of epilepsy patients suffer from refractory temporal lobe epilepsy which is commonly treated with resection of the epileptogenic tissue. However, surgical treatment presents many challenges in locating the epileptogenic focus and thus not all patients become seizure-free following surgery. Advances in techniques can lead to improved localization of the epileptogenic zone and may be validated by correlating MRI with neuropathology of the excised cortical tissue. Focal cortical dysplasias are a neuropathological group of cortical malformations that are often found in cases of refractory epilepsy, however, they are subtle and difficult to quantify. The purpose of this research …

Design Of Radio-Frequency Arrays For Ultra-High Field Mri, Ian R O Connell

Electronic Thesis and Dissertation Repository

Magnetic Resonance Imaging (MRI) is an indispensable, non-invasive diagnostic tool for the assessment of disease and function. As an investigational device, MRI has found routine use in both basic science research and medicine for both human and non-human subjects.

Due to the potential increase in spatial resolution, signal-to-noise ratio (SNR), and the ability to exploit novel tissue contrasts, the main magnetic field strength of human MRI scanners has steadily increased since inception. Beginning in the early 1980’s, 0.15 T human MRI scanners have steadily risen in main magnetic field strength with ultra-high field (UHF) 8 T MRI systems deemed to …

Effect Of L-Ascorbic Acid And All-Trans Retinoic Acid On Smooth Muscle Cells Cultured On Pcl Scaffolds, Brandon Chaffay

Electronic Thesis and Dissertation Repository

The aim of vascular tissue engineering (VTE) is to fabricate tissues that are both mechanically and biologically competent similar to the native vessel they are intended to replace. To this end, the incorporation of sufficient extracellular matrix elastin and collagen is important. The objective of this thesis work was to evaluate the effect of two biochemical factors, l-ascorbic acid (AA) and all-trans retinoic acid (atRA), on elastin synthesis when coronary artery smooth muscle cells were cultured on 3D polycaprolactone (PCL) scaffolds. First, porous PCL scaffolds were fabricated using a solvent casting and particulate leaching approach. The effect of different …