Open Access. Powered by Scholars. Published by Universities.®

Biomedical Engineering and Bioengineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Theses/Dissertations

Dissertations

Articles 1 - 30 of 42

Full-Text Articles in Biomedical Engineering and Bioengineering

Modelling In Vitro Dissolution And Release Of Sumatriptan Succinate From Polyvinylpyrrolidone-Based Microneedles Aided By Iontophoresis, James Paul Ronnander Aug 2019

Modelling In Vitro Dissolution And Release Of Sumatriptan Succinate From Polyvinylpyrrolidone-Based Microneedles Aided By Iontophoresis, James Paul Ronnander

Dissertations

A novel dissolving microneedle array system is developed to investigate permeation of a sumatriptan succinate formulations through the skin aided by iontophoresis. Three formulations consisting of hydrophilic, positively charged drug molecules encapsulated in a water-soluble biologically suitable polymer, polyvinylpyrrolidone (PVP), have been accepted by the U.S. Food and Drug Administration (FDA). The microneedle systems are fabricated with 600 pyramid-shaped needles, each 500 µm tall, on a 0.785-cm2 circular array. In vitro transdermal studies with minipig skin and vertical Franz diffusion cells show > 68% permeation of sumatriptan over a 24-hour period. A combination of microneedle and electrical current ...


Modulation Of Corticospinal Excitability Induced By Paired Associative Stimulation Combined With Movement, Ahmad O. Alokaily Aug 2019

Modulation Of Corticospinal Excitability Induced By Paired Associative Stimulation Combined With Movement, Ahmad O. Alokaily

Dissertations

An essential feature of the brain is its capacity to undergo long-lasting morphological or functional changes in response to experiences or trauma. Advances in noninvasive brain stimulation techniques have led to increased interest in understanding neural mechanisms of neuroplasticity at the network level. Paired associative stimulation (PAS) is one of the most commonly used applications for noninvasive brain stimulation because of its clinical potential as an adjuvant rehabilitative intervention. However, the optimal method for incorporating PAS into rehabilitative activities remains unknown. This dissertation explores different approaches to combining PAS with movement and investigates the enhancement of the specificity of conventional ...


Developmental And Sex Modulated Neurological Alterations In Autism Spectrum Disorder, Azeezat Azeez Aug 2019

Developmental And Sex Modulated Neurological Alterations In Autism Spectrum Disorder, Azeezat Azeez

Dissertations

Autism Spectrum Disorder (ASD) was first described in 1943 by Dr. Leo Kranner in a case study published in The Nervous Child. It is a neurodevelopment disorder, with a range of clinical symptoms. According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), used by clinicians to diagnose mental disorders, a child needs to have persistent social deficits, language impairments, and repetitive behaviors, that cannot be explained by neurological damage or intellectual disability. It is known that children diagnosed with ASD are often are developmentally delayed therefore alterations in the typical developmental trajectory should be a major factor in ...


A Multimodal Approach To Investigate Brain Reorganization After Spinal Cord Injury Using Functional Magnetic Resonance Imaging And Functional Near-Infrared Spectroscopy, Keerthana Deepti Karunakaran May 2019

A Multimodal Approach To Investigate Brain Reorganization After Spinal Cord Injury Using Functional Magnetic Resonance Imaging And Functional Near-Infrared Spectroscopy, Keerthana Deepti Karunakaran

Dissertations

Traumatic Spinal Cord Injury (SCI) results in structural and functional neurological changes at both the brain and the level of the spinal cord. Anatomical studies indicate decreased grey matter volume in sensorimotor and non-sensorimotor regions of the cortex following SCI; whereas, neurophysiological findings mostly report altered functional activity in the sensorimotor nodes of the cortex, subcortex, and cerebellum. Therefore, it is currently unknown whether tissue atrophy observed in non-motor related areas has any concomitant functional consequences. Furthermore, the neural underpinnings of adaptive neuroplasticity after SCI is not well-defined in the current literature. Hence, this dissertation is a pioneer study investigating ...


Dual Modality Optical Coherence Tomography : Technology Development And Biomedical Applications, Farzana Rahmat Zaki May 2019

Dual Modality Optical Coherence Tomography : Technology Development And Biomedical Applications, Farzana Rahmat Zaki

Dissertations

Optical coherence tomography (OCT) is a cross-sectional imaging modality that is widely used in clinical ophthalmology and interventional cardiology. It is highly promising for in situ characterization of tumor tissues. OCT has high spatial resolution and high imaging speed to assist clinical decision making in real-time.

OCT can be used in both structural imaging and mechanical characterization. Malignant tumor tissue alters morphology. Additionally, structural OCT imaging has limited tissue differentiation capability because of the complex and noisy nature of the OCT signal. Moreover, the contrast of structural OCT signal derived from tissue’s light scattering properties has little chemical specificity ...


Interventions Of Waterjet Technology In Skin Incisions, Nadi Atalla May 2019

Interventions Of Waterjet Technology In Skin Incisions, Nadi Atalla

Dissertations

This research explores the use of waterjet (WJ) technology in performing skin incisions. The study defines the analytical relationships between the skin properties and the operating parameters of the WJ which include the skin thickness, its elastic modulus, the WJ pressure, the nozzle’s orifice diameter, its stand-off distance and the traverse speed of the WJ as well as the duration of applying the WJ pressure. An analytical model is developed to measure the depth incision of the skin, the water pressure and the water velocity, while using a WJ. Systemization and optimization models that determine the optimal operating parameters ...


Cardiac Regenerative Medicine: Insights From Healthy And Diseased Engineered Tissues, Pamela Grace Hitscherich Dec 2018

Cardiac Regenerative Medicine: Insights From Healthy And Diseased Engineered Tissues, Pamela Grace Hitscherich

Dissertations

Cardiovascular disease remains the leading cause of mortality in the United States. Current tissue engineering approaches have fallen short of promoting fully functional cardiovascular cells and the post-myocardial infarction microenvironment is still not well understood. These gaps in knowledge are addressed in this dissertation through the development of in vitro engineered cardiac tissues using electroactive materials to enhance the differentiation of pluripotent stem cell derived cardiomyocytes and through the development of in vitro myocardial inflammation models dedicated to understanding cardiomyocytes and macrophages interactions.

Specifically, piezoelectric poly (vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) supports the attachment and survival of mouse embryonic stem cell derived ...


Temporal And Spatial Effects Of Shock Overpressure On Blood-Brain Barrier Permeability In Blast-Induced Traumatic Brain Injury, Matthew Joseph Kuriakose Aug 2018

Temporal And Spatial Effects Of Shock Overpressure On Blood-Brain Barrier Permeability In Blast-Induced Traumatic Brain Injury, Matthew Joseph Kuriakose

Dissertations

Exposure to shock waves is the leading cause of traumatic brain injury (TBI) in military personnel and blast-induced TBI (bTBI) is considered the signature wound in recent conflicts in Iraq and Afghanistan. Many researchers attempt to replicate field-relevant shock waves in laboratory settings through the use of gas-driven shock tubes in order to investigate the generation and propagation of shock waves and also explore possible mechanisms of bTBI. Among several injury mechanisms of bTBI, damage to the blood-brain barrier (BBB) has been identified as a potential candidate and has been the focus of several clinical and experimental investigations aimed to ...


A 3d Simulation Of Leukocyte Adhesion In Blood Flow, Tai-Hsien Wu Jun 2018

A 3d Simulation Of Leukocyte Adhesion In Blood Flow, Tai-Hsien Wu

Dissertations

It has been widely acknowledged that further understanding about the dynamics between blood cells and blood flow can help us gain more knowledge about the causes of diseases and discover more effective treatments. Examples of such dynamics include red blood cell (RBC, or erythrocyte) aggregation, white blood cell (WBC, or leukocyte) margination, and WBC extravasation. WBC extravasation is an important multiple-step process in the inflammatory response and therefore has drawn considerable attention over the past two decades. In this multiple-step process, a WBC undergoes at least four steps, including capture, rolling, firm adhesion, and transmigration, and each step is influenced ...


Prediction Of Forelimb Muscle Activities And Movement Phases Using Corticospinal Signals In The Rat, Sinan Gok May 2018

Prediction Of Forelimb Muscle Activities And Movement Phases Using Corticospinal Signals In The Rat, Sinan Gok

Dissertations

No abstract provided.


Submandibular Mechanical Stimulation Of Upper Airway Muscles To Treat Obstructive Sleep Apnea, Ferhat Erdogan May 2018

Submandibular Mechanical Stimulation Of Upper Airway Muscles To Treat Obstructive Sleep Apnea, Ferhat Erdogan

Dissertations

The extrinsic tongue muscles are activated in coordination with pharyngeal muscles to keep a patent airway during respiration in wakefulness and sleep. The activity of genioglossus, the primary tongue-protruding muscle playing an important role in this coordination, is known to be modulated by several reflex pathways mediated through the mechanoreceptors of the upper airways. The main objective is to investigate the effectiveness of activating these reflex pathways with mechanical stimulations, for the long-term goal of improving the upper airway patency during disordered breathing in sleep. The genioglossus response is examined during mandibular and sub-mandibular mechanical stimulations in healthy subjects during ...


The Use Of Audio Stimulation To Affect Sensorimotor Learning, Gregory Nicholas Ranky Jan 2017

The Use Of Audio Stimulation To Affect Sensorimotor Learning, Gregory Nicholas Ranky

Dissertations

Sensorimotor learning for the hand and fingers can be conducted using both hardware and software components, but the training regime is also important. Using repetitive sequence tapping allows measurement of defined metrics in a controlled, safe environment, and therefore statistical indications for subject improvement.

The process of entrainment, when a subject’s own movements synchronize to an external signal, has been tested in prior studies for memorization and recognition, but has not been investigated for correlation with sensorimotor learning.

This is tested with selected custom isochronic audio tones, combined with sequential finger tapping on a standard computer keyboard.

Whilst there ...


Modeling Subconcussive And Cumulative Subconcussive Impacts Using A Lateral Fluid Percusion Injury Device, Todd Long Jan 2017

Modeling Subconcussive And Cumulative Subconcussive Impacts Using A Lateral Fluid Percusion Injury Device, Todd Long

Dissertations

Repetitive mTBI and concussion are a major risk factor for developing long-term cognitive and behavioral impairments. Curiously, cumulative head injuries sustained over an individuals’ career, involving contact activities (e.g. athletes and military personnel), are beginning to be implicated in long-term consequences, such as dementia. Recently, chronic traumatic encephalopathy (CTE) has gained momentum in the science and medical community as a neurodegenerative disease of repetitive head injuries. CTE was observed at autopsy of former athletes that did not closely correlate with a clinical history of concussion. Thus, suggesting cumulative subconcussive insults may induce long-term damage.


A Multimodal Investigation In Eye Movements, Raj Jaswal Aug 2016

A Multimodal Investigation In Eye Movements, Raj Jaswal

Dissertations

While functional magnetic resonance imaging (fMRI) has identified which regions of interest (ROIs) are functionally active during a vergence movement (inward or outward eye rotation), task-modulated coactivation between ROIs is less understood. This study tests the following hypotheses: (1) significant task-modulated coactivation would be observed between the frontal eye fields (FEFs), the posterior parietal cortex (PPC), and the cerebellar vermis (CV); (2) significantly more functional activity and task-modulated coactivation would be observed in binocularly normal controls (BNCs) compared with convergence insufficiency (CI) subjects; and (3) after vergence training, the functional activity and task-modulated coactivation would increase in CIs compared with ...


Biomimetic And Vascularized 3-D Liver Cancer Model, Derek Yip Aug 2016

Biomimetic And Vascularized 3-D Liver Cancer Model, Derek Yip

Dissertations

Anti-angiogenic drugs have failed to show significant extended mortality, except when co-administered with chemotherapy drugs in clinical trials. This should be predicted by in vitro models, and yet 2D in vitro models of liver cancer co-administered with these two types of drugs show increased cell viability, contradicting clinical trials. In vitro models should mimic clinical trials in order to accurately predict drug outcomes. 2D in vitro models fail because they lack features of the cancer environment such as presence of stromal cells and a vasculature.

In order to achieve a biomimetic and vascularized in vitro model that would better recapitulate ...


A Novel Approach To User Controlled Ambulation Of Lower Extremity Exoskeletons Using Admittance Control Paradigm, Kiran Kartika Karunakaran May 2016

A Novel Approach To User Controlled Ambulation Of Lower Extremity Exoskeletons Using Admittance Control Paradigm, Kiran Kartika Karunakaran

Dissertations

The robotic lower extremity exoskeletons address the ambulatory problems confronting individuals with paraplegia. Paraplegia due to spinal cord injury (SCI) can cause motor deficit to the lower extremities leading to inability to walk. Though wheelchairs provide mobility to the user, they do not provide support to all activities of everyday living to individuals with paraplegia.

Current research is addressing the issue of ambulation through the use of wearable exoskeletons that are pre-programmed. There are currently four exoskeletons in the U.S. market: Ekso, Rewalk, REX and Indego. All of the currently available exoskeletons have 2 active Degrees of Freedom (DOF ...


Compressive Sensing Framework For Mass Spectrometry Data Analysis, Khalfalla Ahmad Kh. Awedat Apr 2016

Compressive Sensing Framework For Mass Spectrometry Data Analysis, Khalfalla Ahmad Kh. Awedat

Dissertations

Mass Spectrometry (MS) data is ideal for identifying unique bio-signatures of diseases. However, the high dimensionality of MS data hinders any promising MS-based proteomics development. The goal of this dissertation is to develop an accurate classification tool by employing compressive sensing (CS). Not only can CS significantly reduce MS data dimensionality, but it also will allow for full reconstruction of original data. The framework developed in this work is based on using L2 and a mixed L2-L1 norms, allowing an overdetermined system to be resolved. The results show that the L2- based algorithm with regularization terms has a better performance ...


Assessment Of A Hand Exoskeleton On Proximal And Distal Training In Virtual Environments For Robot Mediated Upper Extremity Rehabilitation, Kevin Abbruzzese Jan 2016

Assessment Of A Hand Exoskeleton On Proximal And Distal Training In Virtual Environments For Robot Mediated Upper Extremity Rehabilitation, Kevin Abbruzzese

Dissertations

Stroke is the leading cause of disability in the United States with approximately 800,000 cases per year. This cerebral vascular accident results in neurological impairments that reduce limb function and limit the daily independence of the individual. Evidence suggests that therapeutic interventions with repetitive motor training can aid in functional recovery of the paretic limb. Robotic rehabilitation may present an exercise intervention that can improve training and induce motor plasticity in individuals with stroke. An active (motorized) hand exoskeleton that provides support for wrist flexion/extension, abduction/adduction, pronation/supination, and finger pinch is integrated with a pre-existing 3-Degree ...


Hand Control Of Bipedal Balance In Quiet Standing: Implementations For Lower Extremity Exoskeleton, Ala’A Al-Rashdan Jan 2016

Hand Control Of Bipedal Balance In Quiet Standing: Implementations For Lower Extremity Exoskeleton, Ala’A Al-Rashdan

Dissertations

Maintaining stable posture is important for humans, even though it is challenging because of our bipedal structure. One of the main balance related disorders is paraplegia due to spinal cord injury. People with a complete spinal cord injury have motor and sensory impairment that greatly reduces the ability to move their lower extremities. In recent years, lower extremity exoskeletons that apply torques generated by motors to the joints of the person have helped to them stand and walk.

This research is a part of an extended project to build a new exoskeleton for use by individuals with paraplegia due to ...


Plasticity Of The Cortical Representation Of Finger Extensors Induced By Paired Associative Stimulation, Ian Anthony Gerard Lafond Dec 2015

Plasticity Of The Cortical Representation Of Finger Extensors Induced By Paired Associative Stimulation, Ian Anthony Gerard Lafond

Dissertations

This dissertation first explored associative plasticity of the human motor cortical representation with the use of noninvasive transcranial magnetic stimulation (TMS) paired with peripheral electrical stimulation. Paired Associative Stimulation (PAS) has grown in popularity because of its potential clinical applications. PAS techniques are used in combination with electromyography (EMG) measurements to study cortical excitability and features of hand movement. This work focuses on a cohesive approach to answer central questions about: the ideal mechanism to facilitate cortical plasticity via PAS, the interaction between the behavior performed and type of stimulation delivered to the targeted cortical network and the effects of ...


Exploration Of Stimulus Current Energy Reduction And Bifurcation Dynamics In Conductance-Based Neuron Models Using Optimal Control Theory, Michael E. Ellinger Jun 2015

Exploration Of Stimulus Current Energy Reduction And Bifurcation Dynamics In Conductance-Based Neuron Models Using Optimal Control Theory, Michael E. Ellinger

Dissertations

Hodgkin-Huxley type conductance-based models can simulate the effect of time-varying injected stimulus currents on the neuron membrane voltage. The dynamics simulated by these model types enables investigation of the biophysical basis of neuronal activity which is fundamental to higher level function. Broadened understanding the basis of nervous system function could lead to development of effective treatment for related diseases, disorders, and the effects of trauma. In this dissertation, optimal control is used with conductance-based neuron models to develop a "Reduced Energy Input Stimulus Discovery Method." Within the method, an objective function balances two competing criteria: tracking a reference membrane voltage ...


High Frequency Field Potentials Of The Cerebellar Cortex, Jonathan David Groth May 2015

High Frequency Field Potentials Of The Cerebellar Cortex, Jonathan David Groth

Dissertations

The cerebellum plays a crucial role in motor coordination along with basal ganglia and the motor areas of the cerebral cortex. Both somatosensory and the cerebro-cerebral pathways bring in massive amounts of neural information to the cerebellum. The output of the cerebellar cortex projects to various motor cortices as well as down to the spinal cord to make its contributions to the motor function.

The origin and function of the field potential oscillations in the cerebellum, especially in the high frequencies, have not been explored sufficiently. The primary objective of this study was to investigate the spatio-temporal characteristics of high ...


Monitoring Of Cerebellar Injury Using Micro Ecog Signals In Ketamine/Xylazine Treated Rats, Gokhan Ordek Dec 2014

Monitoring Of Cerebellar Injury Using Micro Ecog Signals In Ketamine/Xylazine Treated Rats, Gokhan Ordek

Dissertations

Much of the cerebellar research has been conducted in anesthetized animals, particularly using ketamine/xylazine combination in rats, and yet the absolute impact of the anesthesia on the neural circuit remains unanswered . In the current study, spontaneous electrical activity and sensory evoked potentials from the cerebellar surface with chronically implanted, flexible-substrate, multielectrode arrays in rats were collected and analyzed with the motor cortex signals. The power spectra and the intercontact coherence plots of the spontaneous activity in the awake-quiet animals extended up to 800 Hz in the cerebellum and only up to 200 Hz in the motor cortex. Ketamine/xylazine ...


Fabrication, Testing And Analysis Of A Fatigue Sensor For Structural Health Monitoring, Subash Gokanakonda Dec 2014

Fabrication, Testing And Analysis Of A Fatigue Sensor For Structural Health Monitoring, Subash Gokanakonda

Dissertations

A novel fatigue monitoring sensor (FMS) is designed, fabricated and tested for detecting and monitoring the fatigue damage and estimating the remaining life of structures and components subjected to cyclic loads. The concept is based on the characteristics of stress / strain life cycle relationship of engineering materials. Sensor consists of alternate slots and strips having different strain magnification factor with respect to the nominal strain. The sensor is designed in such a way that the strips will experience the strain which closely resemble the actual strain distribution in the notch or critical area of the component. The sensor can be ...


Characterizing Motor Control Signals In The Spinal Cord, Yi Guo May 2014

Characterizing Motor Control Signals In The Spinal Cord, Yi Guo

Dissertations

The main goal of this project is to develop a rodent model to study the central command signals generated in the brain and spinal cord for the control of motor function in the forearms. The nature of the central command signal has been debated for many decades with only limited progress. This thesis presents a project that investigated this problem using novel techniques. Rats are instrumented to record the control signals in their spinal cord while they are performing lever press task they are trained in. A haptic interface and wireless neural data amplifier system simultaneously collects dynamic and neural ...


Construction And Assessment Of A Computer Graphics-Based Model For Wheelchair Propulsion, Brooke Marie Odle Dec 2013

Construction And Assessment Of A Computer Graphics-Based Model For Wheelchair Propulsion, Brooke Marie Odle

Dissertations

Upper limb overuse injuries are common in manual wheelchair using persons with spinal cord injury (SCI), especially those with tetraplegia. Biomechanical analyses involving kinetics, kinematics, and muscle mechanics provide an opportunity to identify modifiable risk factors associated with wheelchair propulsion and upper limb overuse injuries that may be used toward developing prevention and treatment interventions. However, these analyses are limited because they cannot estimate muscle forces in vivo. Patient-specific computer graphics-based models have enhanced biomechanical analyses by determining in vivo estimates of shoulder muscle and joint contact forces. Current models do not include deep shoulder muscles. Also, patient-specific models have ...


The Effect Of Mechanical Vestibular Stimulation On Muscle Tone And Spasticity In Individuals With Neurological Impairment, Ghaith J. Androwis Dec 2013

The Effect Of Mechanical Vestibular Stimulation On Muscle Tone And Spasticity In Individuals With Neurological Impairment, Ghaith J. Androwis

Dissertations

In the desire to better understand spasticity mainly in Cerebral Palsy (CP) and to examine vestibular stimulation as a future intervention for .muscle tone reduction, and to be able to describe the change in level of spasticity in subjects with disability and describe interventions effects, a series of experiments are done on children with spasticity. In addition to understanding the otoliths in the vestibular system and their projections, properties and pathways a more important major objective of this work is to validate the changes in otoliths signal caused by vestibular stimulation based on the Equilibrium Point Hypothesis and the inclusion ...


Rate Alterable Traumatic Brain Injury Device For Rodent Models, Radia Abdul Wahab Dec 2013

Rate Alterable Traumatic Brain Injury Device For Rodent Models, Radia Abdul Wahab

Dissertations

Traumatic Brain Injury (TBI) is a physical impact to the head resulting in functional deficits in memory and motor systems. TBI is a prevalent problem occurring in 1.7 million people annually in the United States (Faul et al. 2010). TBIs can differ greatly in terms of the biomechanics of the impact such as magnitude, direction and rate. Indeed, it is likely that the wide range of TBI outcomes may be due to the physical characteristics of the trauma. Studies to date on impact have used injury devices with limited alterable parameters. Therefore, the existing impact studies have considered the ...


Quantification Of Neural Substrates Of Vergence System Via Fmri, Yelda Alkan Dec 2012

Quantification Of Neural Substrates Of Vergence System Via Fmri, Yelda Alkan

Dissertations

Vergence eye movement is one of the oculomotor systems which allow depth perception via disconjugate movement of the eyes. Neuroimaging methods such as functional magnetic resonance imaging (fMRI) measure neural activity changes activity in the brain while subjects perform experimental tasks. A rich body of primate investigations on vergence is already established in the neurophysiology literature; on the other hand, there are a limited number of fMRI studies on neural mechanisms behind the vergence system.

The results demonstrated that vergence system shares neural sources and also shows differentiation within the boundaries of frontal eye fields (FEF) and midbrain of the ...


Fabrication And Evaluation Of A Collagen-Based Fiber-Gel Three-Dimensional Construct For Peripheral Nerve Repair, Mevan Lakmal Siriwardane Dec 2012

Fabrication And Evaluation Of A Collagen-Based Fiber-Gel Three-Dimensional Construct For Peripheral Nerve Repair, Mevan Lakmal Siriwardane

Dissertations

Nerve regeneration following a peripheral nerve injury often relies on growth cone- mediated guidance and the presence of Schwann cells to support the regenerating axons and remyelinate portions of denervated nerve pathways. The emphasis of this work is to develop a synthetic nervous tissue construct that contains similar basal lamina or extracellular matrix to peripheral nerve in order to achieve a level of effectiveness in nerve repair and future peripheral nerve regeneration applications. To this end, three- dimensional nervous tissue constructs consisting of type I collagen are fabricated into a composite biomaterial scaffold to promote contact-guided growth of neuronal and ...