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Full-Text Articles in Biomedical Engineering and Bioengineering

Predicting And Preventing Traumatic Brain Injury: A Novel Computational Approach, Kewei Bian Aug 2019

Predicting And Preventing Traumatic Brain Injury: A Novel Computational Approach, Kewei Bian

Electronic Thesis and Dissertation Repository

Traumatic brain injury (TBI) is a severe health problem for society. Meanwhile, predicting and preventing TBI remains challenging in the field. Peak rotational velocity was demonstrated to be correlated to brain strain responses, and hence could potentially serve as a good predictor for brain injury. Brain strain was influenced by impact direction, deceleration and impact loading curve shapes. Wearing helmets is an effective way to protect the brain from TBI, but there lacks a study on evaluating helmet performance based on both energy absorption and brain strain response, which this study addressed. Interestingly, helmet shell absorbed around half of the ...


The Development Of A Temporomandibular Force Simulator To Study Craniofacial Strain In-Vitro, Kenneth Kc Ip Jun 2018

The Development Of A Temporomandibular Force Simulator To Study Craniofacial Strain In-Vitro, Kenneth Kc Ip

Electronic Thesis and Dissertation Repository

An in-vitro musculoskeletal loading simulator was developed to replicate the internal forces of mastication, and then employed in a comparison of clinically relevant facial fracture repairs. Muscle forces are simulated by pneumatic pistons via 3D printed mounts that are reverse-engineered from CT scan to match muscle attachment sites, which are adhered to bone in order to simulate native stress distributions. Bite force and bone strain pattern of the craniofacial structure under load were measured using a force sensor and strain gauges respectively. In a series of five fresh-frozen cadaveric heads, it was found that strain patterns of the craniofacial structure ...


A Numerical Investigation Of Human Cough Jet Development And Droplet Dispersion, Ran Bi Apr 2018

A Numerical Investigation Of Human Cough Jet Development And Droplet Dispersion, Ran Bi

Electronic Thesis and Dissertation Repository

As part of the Western Cold and Flu aerosol (WeCoF) studies, the present study provides Computational Fluid Dynamics (CFD) modelling of human cough flow. The cough flow is characterized in two different aspects, the flow field and the droplets. In the study of the flow field of coughing, various dynamic characteristics, including the velocity variation, streamwise penetration and power spectral density, are examined. CFD simulations using two different approaches, the unsteady Reynolds Averaged Navier-Stokes (URANS) and the large eddy simulation (LES), are performed for comparison purposes. The numerical results are validated by the experimental data obtained from the measurements by ...


Examining Reverse Total Shoulder Arthroplasty Baseplate Fixation In Patients With E2-Type Glenoid Erosion, Matthew D. Mahaffy Feb 2018

Examining Reverse Total Shoulder Arthroplasty Baseplate Fixation In Patients With E2-Type Glenoid Erosion, Matthew D. Mahaffy

Electronic Thesis and Dissertation Repository

Superior glenoid erosion of the shoulder joint is a result of humeral subluxation caused by rotator cuff tears, and can be addressed using implants, specifically reverse total shoulder arthroplasty. This thesis examined the regional variations of bone present in superiorly eroded glenoids, established a baseline for regular RTSA baseplate fixation in patients with this defect, and compared the effect of geometric baseplate differences on implant fixation. The superiorly eroded glenoids demonstrated similar regional bone density variations as normal glenoids, and the superior and inferior regions of the glenoid demonstrated the densest and least dense cancellous bone, respectively. These regions also ...


Development Of An Active Finger Motion Simulator: With In-Vitro Assessments Of Tendon Loads And Joint Kinematics, Mohammad Haddara Nov 2017

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 ...


Influence Of Scapular Notching On Contact Mechanics And Simulator Wear Of Reverse Total Shoulder Arthroplasty Implants, Michael William Griffiths Oct 2017

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 Sep 2017

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 ...


The Effect Of Radial And Ulnar Length Change On Distal Forearm Loading, Ahaoiza D. Isa Aug 2017

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 ...


Assessment Of The Non-Linear Stress-Strain Characteristics Of Poly (Vinyl Alcohol) Cryogel, Mojdeh Zakeri Mar 2017

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 ...


The Role Of Scapular Morphology In Reverse Shoulder Arthroplasty, Ashish Gupta Dec 2016

The Role Of Scapular Morphology In Reverse Shoulder Arthroplasty, Ashish Gupta

Electronic Thesis and Dissertation Repository

Baseplate fixation in a reverse shoulder arthroplasty depends on adequate bone stock. In cases of severe glenoid bone loss and revision shoulder arthroplasty, deficiency of the glenoid vault compels the surgeon to attain screw fixation in the three columns of the scapula. The relationship of these columns demonstrated that the coracoid is closer to the lateral scapular pillar in females than in males. Significant gender dimorphism exists between the orientations of the three columns. The gender dimorphism is further evaluated by anthropometric measurements of the scapular body and the glenoid. The clinical significance lies in the ability to reconstruct the ...


A Biomechanical Investigation Of Scaphoid And Lunate Kinematics During Wrist Motion, Helen L. Stoesser Oct 2016

A Biomechanical Investigation Of Scaphoid And Lunate Kinematics During Wrist Motion, Helen L. Stoesser

Electronic Thesis and Dissertation Repository

Carpal kinematics have been previously investigated, yet there remains no consensus regarding the relative contribution of each bone to total wrist motion. A more detailed understanding of carpal kinematics is essential in the effective diagnosis and treatment of injuries of the wrist, as many injuries manifest as an alteration in intercarpal kinematics. The scapholunate (SL) ligament is one of the most commonly injured intercarpal articulations resulting in a cascade of degenerative changes included cartilage wear and altered joint kinematics. The SL ligament is considered the primary stabilizer of the SL joint but is surrounded by a complex network of secondary ...


A Novel Composite Material-Based Computational Model For Left Ventricle Biomechanics Simulation, Seyyed Mohammad Hassan Haddad Jul 2016

A Novel Composite Material-Based Computational Model For Left Ventricle Biomechanics Simulation, Seyyed Mohammad Hassan Haddad

Electronic Thesis and Dissertation Repository

To model cardiac mechanics effectively, various mechanical characteristics of cardiac muscle tissue including anisotropy, hyperelasticity, and tissue active contraction characteristics must be considered. Some of these features cannot be implemented using commercial finite element (FE) solvers unless additional custom-developed computer codes/subroutines are appended. Such codes/subroutines are unavailable for the research community. Accordingly, the overarching objective of this research is to develop a novel LV mechanics model which is implementable in commercial FE solvers and can be used effectively within inverse FE frameworks towards cardiac disease diagnosis and therapy. This was broken down into a number of objectives. The ...


Markerless Radiostereogammetry Of The Shoulder Joint In Humans: Comparisons Of Scapulohumeral Kinematics Between Individuals With Healthy And Supraspinatus-Impaired Shoulders, Ashley N. Hannon Apr 2016

Markerless Radiostereogammetry Of The Shoulder Joint In Humans: Comparisons Of Scapulohumeral Kinematics Between Individuals With Healthy And Supraspinatus-Impaired Shoulders, Ashley N. Hannon

Electronic Thesis and Dissertation Repository

The purpose of this collection of studies was to further develop the knowledge of shoulder motion in order to better understand joint function through direct measurement of 3D scapulohumeral joint kinematics using a technique of high accuracy. Markerless, bi-planar fluoroscopic radiostereometric analysis using a generic shoulder model was developed in this thesis, reducing the amount of radiation exposure to subjects. The studies compared kinematic data of the scapulohumeral joint in six degrees of freedom with a precise, in-vivo measuring technique. Data were collected on young and older healthy individuals, individuals with a torn supraspinatus and post-surgical intervention.

Although this generic ...


Effect Of Hemiarthroplasty Implant Contact Geometry And Material On Early Cartilage Wear, Alana Khayat Sep 2015

Effect Of Hemiarthroplasty Implant Contact Geometry And Material On Early Cartilage Wear, Alana Khayat

Electronic Thesis and Dissertation Repository

Hemiarthroplasty is a minimally invasive, cost-effective alternative to total arthroplasty in joints of the upper limb. Though these procedures reduce patient morbidity while restoring joint kinematics, their longevity is limited by wear of the adjacent cartilage. This work investigates the roles of contact geometry and implant stiffness on cartilage wear with the aim of elucidating the mechanics that contribute to cartilage damage. An in vitro study examined the influence of implant geometry on cartilage wear using a pin-on-plate wear simulator. A significant decrease in volumetric wear was observed as contact area increased, which suggests that maximizing contact area should be ...


Blood Supply To The Brain Via The Carotid Arteries: Examining Obstructive And Sclerotic Disorders Using Theoretical And Experimental Models, Onaizah Onaizah Aug 2015

Blood Supply To The Brain Via The Carotid Arteries: Examining Obstructive And Sclerotic Disorders Using Theoretical And Experimental Models, Onaizah Onaizah

Electronic Thesis and Dissertation Repository

Stroke remains one of the leading causes of death in North America. Approximately half of all ischemic episodes are a direct result of carotid artery disease, which can be categorized into either obstructive or sclerotic disease. Obstructive disease is a result of plaque development that imposes a direct limitation on the physical space available for blood flow. Sclerotic disease involves the hardening of the arteries as is often a result of aging and disease. While the impact of vessel stiffening is not as obvious, it does interfere with wave propagation. Effects of obstructive and sclerotic disease were studied using a ...


Osteoarthritis Induced Glenoid Morphology And Bone Quality: An Evaluation Of Augmented Glenoid Components, Nikolas K. Knowles Apr 2015

Osteoarthritis Induced Glenoid Morphology And Bone Quality: An Evaluation Of Augmented Glenoid Components, Nikolas K. Knowles

Electronic Thesis and Dissertation Repository

Osteoarthritis of the glenoid results in regional bone density variations and bone loss that may compromise early component fixation and support. The two common morphologies, symmetric and asymmetric erosion, were characterized by bone density and morphology, and assessed on the basis of bone removal and bone quality in the context of augmented glenoid components. The bone strain field was also compared when different augmented glenoid components underwent simulated joint loading using finite element analysis.

Asymmetrically eroded glenoids were found to have denser bone (p


Characterization Of A Contact-Stylus Surface Digitization Method Using Collaborative Robots: Accuracy Evaluation In The Context Of Shoulder Replacement Or Resurfacing, Sara Saud Zimmo Sep 2014

Characterization Of A Contact-Stylus Surface Digitization Method Using Collaborative Robots: Accuracy Evaluation In The Context Of Shoulder Replacement Or Resurfacing, Sara Saud Zimmo

Electronic Thesis and Dissertation Repository

Total shoulder arthroplasty (TSA) is the third most common joint replacement. While robot-assisted hip and knee replacement technologies have enjoyed extensive development, this has been limited in the upper limb. This work focused on quantifying the localization accuracy of a robotic system, and evaluating its efficacy in the context of TSA.

A collaborative robot was fitted with a stylus tip to perform manual surface digitizations using the robot’s encoder output. In the first experiment, two precision-machined master cubes, representing the working volume around a glenoid structure, were used for system validation. Next, cadaveric glenoids were digitized and compared to ...


The Effect Of Fixation Plate Length On Spinal Instability Following Anterior Cervical Plate Fixation For The Repair Of In Vitro Flexion-Distraction Injuries, Abdulaziz J. Al-Kuwari Sep 2014

The Effect Of Fixation Plate Length On Spinal Instability Following Anterior Cervical Plate Fixation For The Repair Of In Vitro Flexion-Distraction Injuries, Abdulaziz J. Al-Kuwari

Electronic Thesis and Dissertation Repository

Abstract:

The Effect of Fixation Plate Length on Spinal Instability Following Anterior Cervical Plate Fixation for the Repair of in Vitro Flexion-Distraction Injuries

Introduction: Anterior cervical decompression and fusion with a plate (ACDFP) is a commonly performed treatment following a traumatic injury to the subaxial cervical spine. The purpose of the presented work was to determine the biomechanical effect of plate length on cervical spine kinematic stability following ACDFP stabilization for a simulated traumatic injury.

Methods: Eleven fresh-frozen cadaveric C5-C6 and C6-C7 motion segments were examined in this study. To assess kinematics, flexibility testing was performed on each specimen using ...


Design And Assessment Of An Experimental Test Setup For Use In Studies On The Vibrational Response Of The Head To Impact, Claudia M. Blandford Aug 2014

Design And Assessment Of An Experimental Test Setup For Use In Studies On The Vibrational Response Of The Head To Impact, Claudia M. Blandford

Electronic Thesis and Dissertation Repository

With the mortality, disability and socioeconomic costs associated with head injury, head impact biomechanics is important to developing injury criterions and safety tolerances. However, the current state of knowledge is contradictory and vague. This thesis will contribute to research done on the vibrational response of the head to impact by discussing two studies. The first will describe the design, implementation and validation of a head impactor setup specific for the study of the frequency response of the skull. An impactor capable of producing sub-5ms duration, sub-fracture impacts was successfully designed. The apparatus was validated by comparing the results of a ...


Computational Techniques To Predict Orthopaedic Implant Alignment And Fit In Bone, Seyed Kamaleddin Mostafavi Yazdi Apr 2014

Computational Techniques To Predict Orthopaedic Implant Alignment And Fit In Bone, Seyed Kamaleddin Mostafavi Yazdi

Electronic Thesis and Dissertation Repository

Among the broad palette of surgical techniques employed in the current orthopaedic practice, joint replacement represents one of the most difficult and costliest surgical procedures. While numerous recent advances suggest that computer assistance can dramatically improve the precision and long term outcomes of joint arthroplasty even in the hands of experienced surgeons, many of the joint replacement protocols continue to rely almost exclusively on an empirical basis that often entail a succession of trial and error maneuvers that can only be performed intraoperatively. Although the surgeon is generally unable to accurately and reliably predict a priori what the final malalignment ...


The Development And Application Of A Forearm Simulator To Investigate Radial Head Biomechanics, Brent A. Lanting Apr 2014

The Development And Application Of A Forearm Simulator To Investigate Radial Head Biomechanics, Brent A. Lanting

Electronic Thesis and Dissertation Repository

The forearm is a complex articular unit, with poorly understood biomechanics. A novel forearm simulator to facilitate physiologic testing of cadavers for multiple clinical scenarios was designed, manufactured and validated. A number of outcome measurements were potentiated including the forearm’s resistance to rotation, radiocapitellar contact pressure and area as well as IOM loads. Testing of changes to forearm biomechanics due to radial head excision and variations of radial head arthroplasty dimensions was conducted. Radial head arthroplasty using the correct radial head length and diameter recreated the biomechanics of an intact forearm. Radial head excision as well an implant of ...


Biomechanical Investigations Of Medial Opening Wedge High Tibial Osteotomy: Gait Analysis, Materials Testing And Dynamic Radiography, Kristyn Leitch Apr 2014

Biomechanical Investigations Of Medial Opening Wedge High Tibial Osteotomy: Gait Analysis, Materials Testing And Dynamic Radiography, Kristyn Leitch

Electronic Thesis and Dissertation Repository

This thesis aimed to develop and assess biomechanical methods to assist in the evaluation of medial opening wedge high tibial osteotomy (HTO). Five studies using diverse methods were performed, including three-dimensional (3D) gait analysis, materials testing of HTO fixation plates, and dynamic radiography in patients after surgery. Study 1 compared external knee joint moments during walking before and after varus or valgus producing osteotomy in patients with lateral or medial compartment osteoarthritis, and in healthy participants. The results highlighted the importance of alignment on gait biomechanics with changes in frontal plane angular impulse highly correlated to changes in mechanical axis ...


Development Of An In-Vitro Passive And Active Motion Simulator For The Investigation Of Shoulder Function And Kinematics, Joshua W. Giles Apr 2014

Development Of An In-Vitro Passive And Active Motion Simulator For The Investigation Of Shoulder Function And Kinematics, Joshua W. Giles

Electronic Thesis and Dissertation Repository

Injuries and degenerative diseases of the shoulder are common and may relate to the joint’s complex biomechanics, which rely primarily on soft tissues to achieve stability. Despite the prevalence of these disorders, there is little information about their effects on the biomechanics of the shoulder, and a lack of evidence with which to guide clinical practice. Insight into these disorders and their treatments can be gained through in-vitro biomechanical experiments where the achieved physiologic accuracy and repeatability directly influence their efficacy and impact.

This work’s rationale was that developing a simulator with greater physiologic accuracy and testing capabilities ...


The Effect Of Stem Surface Treatment And Substrate Material On Joint Replacement Stability: An In-Vitro Investigation Into The Stem-Cement Interface Mechanics Under Various Loading Modes, Yara K. Hosein Aug 2013

The Effect Of Stem Surface Treatment And Substrate Material On Joint Replacement Stability: An In-Vitro Investigation Into The Stem-Cement Interface Mechanics Under Various Loading Modes, Yara K. Hosein

Electronic Thesis and Dissertation Repository

Mechanical loosening is a common mode of joint replacement failure. For cemented implants, loosening at the implant-cement interface may be affected by stem surface design. Altering the surface topography facilitates the infiltration of bone cement onto the stem, creating a mechanical interlock, improving interface stability. However, few in-vitro studies have investigated this. Therefore, the purpose of this thesis was to investigate the effect of stem surface treatments and substrate materials on stem-cement interface stability in-vitro.

Four separate studies were performed to assess the stability of various stem surface treatments, with two substrate materials, under three loading modes. Titanium and cobalt ...


Properties And Applications Of Sensory Outcome Measures In Carpal Tunnel Syndrome, Derek Km Cheung Dec 2012

Properties And Applications Of Sensory Outcome Measures In Carpal Tunnel Syndrome, Derek Km Cheung

Electronic Thesis and Dissertation Repository

This thesis aimed to determine the psychometric properties and applications of sensory threshold tools and outcome measures in patients with Carpal Tunnel Syndrome (CTS). The first chapter is a psychometric study that defines clinically important difference (CID), construct validity and responsiveness of touch and vibration threshold tools and in the Symptoms Severity Scale (SSS). The study found the CID for the PSSD and for the SSS was 0.15g/mm2 and 0.50 respectively. The study also found that the Vibrometer was more representative of hand function and responsive compared PSSD. The second objective of this thesis was to ...


Modeling Lung Tissue Motions And Deformations: Applications In Tumor Ablative Procedures, Ali Sadeghi Naini May 2011

Modeling Lung Tissue Motions And Deformations: Applications In Tumor Ablative Procedures, Ali Sadeghi Naini

Electronic Thesis and Dissertation Repository

Various types of motion and deformation that the lung undergoes during minimally invasive tumor ablative procedures have been investigated and modeled in this dissertation. The lung frequently undergoes continuous large respiratory deformation, which can greatly affect the pre-planned outcome of the operation, hence deformation compensation becomes necessary. The first type of major deformation involved in a target lung throughout a tumor ablative procedure is the one encountered in procedures where the lung is totally deflated before starting the operation. A consequence of this deflation is that pre-operative images (acquired while the lung was partially inflated) become inaccurate for targeting the ...