Biomedical Engineering and Bioengineering Commons^™

Preparation And Characterization Of An Electrospun Gelatin/Dendrimer Hybrid Nanofiber Dressing, Alicia P. Smith-Freshwater

Theses and Dissertations

A novel dendritic wound dressing was designed and characterized for its potential to treat chronic wounds. Comprised of gelatin, dendrimer, synthetic polymer and antibiotics, the dressing was electrospun to mimic the natural extracellular matrix (ECM). Gelatin is biocompatible, biodegradable, non-toxic, and easily available. The antibiotic, doxycycline, has the ability to inhibit matrix metalloproteinases. Matrix metalloproteinases, which occur in excess in chronic wounds, degrade the reconstituted ECM. Starburst™ polyamidoamine (PAMAM) dendrimer G3.5, which provides a versatile and structurally controlled architecture to construct nanomedicine, was covalently bonded to the gelatin backbone and electrospun into nanofibers with gelatin, doxycycline and stabilizing polymers. The …

The Use Of A Tri-Axial Accelerometer To Measure Changes In Lower Extremity Fatigue During Functional Activity, Kristin Morgan

Theses and Dissertations

In 2004, the National Collegiate Athletic Association reported ankle sprain as the most frequent injury in soccer, basketball, and volleyball players. Further research found an increased likelihood with fatigue. Measuring fatigue during functional activities has been a longstanding problem. In this study, changes in ankle biomechanics were measured using a tri-axial accelerometer embedded in the shoe as subjects (n=12) performed a fatiguing activity. Data were collected from the accelerometer and from established devices that are considered the industry gold standard. Several kinetic and kinematic accelerometer derived variables were highly correlated with these standards (r2>0.90) and were associated with changes …

Development Of An Electroencephalography-Based Brain-Computer Interface Supporting Two-Dimensional Cursor Control, Dandan Huang

Theses and Dissertations

This study aims to explore whether human intentions to move or cease to move right and left hands can be decoded from spatiotemporal features in non-invasive electroencephalography (EEG) in order to control a discrete two-dimensional cursor movement for a potential multi-dimensional Brain-Computer interface (BCI). Five naïve subjects performed either sustaining or stopping a motor task with time locking to a predefined time window by using motor execution with physical movement or motor imagery. Spatial filtering, temporal filtering, feature selection and classification methods were explored. The performance of the proposed BCI was evaluated by both offline classification and online two-dimensional cursor …

Spatial Detection Of Multiple Movement Intentions From Sam-Filtered Single-Trial Meg For A High Performance Bci, Harsha Battapady

Theses and Dissertations

The objective of this study is to test whether human intentions to sustain or cease movements in right and left hands can be decoded reliably from spatially filtered single trial magneto-encephalographic (MEG) signals. This study was performed using motor execution and motor imagery movements to achieve a potential high performance Brain-Computer interface (BCI). Seven healthy volunteers, naïve to BCI technology, participated in this study. Signals were recorded from 275-channel MEG and synthetic aperture magnetometry (SAM) was employed as the spatial filter. The four-class classification for natural movement intentions was performed offline; Genetic Algorithm based Mahalanobis Linear Distance (GA-MLD) and direct-decision …

Fabrication And Characterization Of Bioactive, Composite Electrospun Bone Tissue Engineering Scaffolds Intended For Cleft Palate Repair, Parthasarathy Madurantakam

Theses and Dissertations

Tissue Engineering is a scientific discipline that aims to regenerate tissues and organs that are diseased, lost or congenitally absent. It encompasses the use of suitable synthetic equivalents of native extracellular matrix that may or may not be supplemented with cells or relevant growth factors. Such scaffolds are designed to reside at the site of implantation for a variable period of time during which they induce the regeneration of native tissue. During this time, they also provide a template for new cells to attach, infiltrate, differentiate into appropriate phenotype and eventually restore function of the concerned tissue. Among the factors …

Computational Modeling Of The Helical Axis In The Human Knee--Detecting Changes In The Transverse Plane, Emily Carney

Theses and Dissertations

The purpose of this study was to build a helical axis algorithm capable of detecting changes in the helical axis intersection of the tibia and femur in human knees. This algorithm was designed and tested using three models: a multiplanar rigid body model, a mathematical model, and a cylinder model. The multiplanar rigid body model closely mimics knee movement without supporting ligamentous structures, thus the movement was unconstrained. In this model kinematic position data were collected using both MotionMonitor™ (MotionMonitor™ Version 7.7, Innovative Sports Training, Chicago, IL) and Vicon Nexus 1.3 software system (Oxford Metrics Group, Oxford, UK). To test …

Tissue Engineering Cellularized Silk-Based Ligament Analogues, Scott Sell

Theses and Dissertations

The resurgence, and eventual rise to prominence in the field of tissue engineering, that electrospinning has experienced over the last decade speaks to the simplicity and adaptability of the process. Electrospinning has been used for the fabrication of tissue engineering scaffolds intended for use in nearly every part of the human body: blood vessel, cartilage, bone, skin, nerve, connective tissue, etc. Diverse as the aforementioned tissues are in both form and function, electrospinning has found a niche in the repair of each due to its capacity to consistently create non-woven structures of fibers ranging from nano-to-micron size in diameter. These …

Structural And Functional Considerations In The Design Of Collagen-Based Electrospun Scaffolds, Chantal Ayres

Theses and Dissertations

Electrospinning can be used to selectively process a variety of natural and synthetic polymers into highly porous scaffolds composed of nano-to-micron diameter fibers. This process shows great potential as a gateway to the development of physiologically relevant tissue engineering scaffolds. In this study we examine the structural and functional considerations regarding electrospun scaffolds for dermal template applications using novel quantification techniques. In order to characterize scaffold structure, a technique utilizing the fast Fourier transform was developed to systematically quantify fiber alignment and evaluate how different electrospinning parameters impact the structure and material properties of an electrospun scaffold. Gelatin was suspended …

Botulinum Toxin For Non-Surgical Lateral Release In Subjects With Patellofemoral Pain, Laura Maple

Theses and Dissertations

Previous studies for treating Patellofemoral Pain Syndrome (PFPS) are controversial regarding the effectiveness in alleviating anterior knee pain (AKP). The muscular imbalance between the vastus medialis oblique/vastus lateralis (VMO/VL) may be the underlying mechanical issue causing PFPS. It is hypothesized that Botox can decrease the force production capability of the lateral musculature mechanically similar to surgery. Strengthening the VMO while using Botox treatment can alleviating the muscular imbalance that occurs with subjects with PFPS. A double blind study, having all participants blinded and uninformed of the injection contents, was implemented to test this hypothesis testing three female subjects. Four knees …

Position Concordant - Haptic Mouse, Ravi Rastogi

Theses and Dissertations

Haptic mice, computer mice modified to have a tactile display, have been developed to enable access to computer graphics by individuals who are blind or visually impaired. Although these haptic mice are potentially very helpful and have been frequently used by the research community, there are some fundamental problems with the mouse, limiting its acceptance. In this paper we have identified the problems and have suggested solutions using one haptic mouse, the VT Player. We found that our modified VT Player showed significant improvement both in terms of the odds of obtaining a correct responses and the time to perform …

A Binary Method For Simple And Accurate Two-Dimensional Cursor Control From Eeg With Minimal Subject Training, Turan A. Kayagil, Ou Bai, Craig S. Henriquez, Peter Lin, Stephen J. Furlani, Sherry Vorbach, Mark Hallett

Biomedical Engineering Publications

Background

Brain-computer interfaces (BCI) use electroencephalography (EEG) to interpret user intention and control an output device accordingly. We describe a novel BCI method to use a signal from five EEG channels (comprising one primary channel with four additional channels used to calculate its Laplacian derivation) to provide two-dimensional (2-D) control of a cursor on a computer screen, with simple threshold-based binary classification of band power readings taken over pre-defined time windows during subject hand movement.

Methods

We tested the paradigm with four healthy subjects, none of whom had prior BCI experience. Each subject played a game wherein he or she …

Organ Motion And Image Guidance In Radiation Therapy, Jining Zhou

Theses and Dissertations

Organ motion and inaccurate patient positioning may compromise radiation therapy outcome. With the aid of image guidance, it is possible to allow for a more accurate organ motion and motion control study, which could lead to the reduction of irradiated healthy tissues and possible dose escalation to the target volume to achieve better treatment results. The studies on the organ motion and image guidance were divided into the following four sections. The first, the interfractional setup uncertainties from day-to-day treatment and intrafractional internal organ motion within the daily treatment from five different anatomic sites were studied with Helical TomoTherapy unit. …

Development Of An Inexpensive, Haptic Graphical Display Device, David Burch

Theses and Dissertations

A finger-worn haptic device capable of rendering 2-D graphics through vibrotactile feedback is presented. The device development is presented from its initial stages of being a stylus design using a photo-interrupter optical sensor and pager-motor actuator to a small case worn on the finger using a RGB color sensor and a piezoelectric actuator. Testing of the latest prototype design shows that it has a spatial sensitivity (<2mm) comparable to natural touch (~1mm) and can be used to output a variety of vibrotactile textures. The design can be expanded for a multiple finger, independent device, while remaining affordable (<$100) and highly portable (<500g).

Synthesis And Characterization Of Novel Temperature-Responsive Dendritic Peg-Pdlla Star Polymers For Drug Delivery, Arunvel Kailasan

Theses and Dissertations

This study describes a novel thermoresponsive dendritic polyethylene glycol-poly(D, L-lactide) (PEG-PDLLA) core-shell nanoparticle with potential for drug delivery and controlled release. A series of dendritic PEG-PDLLA nanoparticles were synthesized through conjugation of PEG to Starburst™ polyamidoamine (PAMAM) dendrimer G3.0 and subsequent ring-opening polymerization of DLLA, in which PEG chain length (i.e., MW=1500, 6000 or 12000 Dalton) was varied; however, the feeding molar ratio of DLLA monomers to the overall PEG repeat units on the dendrimer surface was kept at 1:1. Linear PEG-PDLLA copolymers were also syntheiszed under the same condition and used as control. According to our results, dendritic PEG-PDLLA …

Angiogenic Potential Of Human Macrophages On Electrospun Bioresorbable Vascular Grafts, Koyal Garg

Theses and Dissertations

The aim of this study was to investigate macrophage interactions with electrospun scaffolds and quantify the expression of vital angiogenic growth factors in vitro. This study will further help in evaluating the potential of these electrospun constructs as vascular grafts for tissue repair and regeneration in situ. Human peripheral blood macrophages were seeded in serum free media on electrospun (10 mm) discs of polydioxanone (PDO), elastin and PDO:elastin blends (50:50, 70:30 and 90:10). The growth factor secretion was analyzed by ELISA. Macrophages produced high levels of vascular endothelial growth factor (VEGF) and acidic fibroblast growth factor (aFGF). Transforming growth factor …

Synthesis And Characterization Of Polyionic Hydrogels, Pooja Desai

Theses and Dissertations

In this study we describe novel polyionic dendrimer – PEG hydrogels for drug delivery. Hydrogels have a crosslinked insoluble network of polymer chains, which have found many applications including drug delivery and tissue regeneration. Dendrimers provide an ideal platform for drug delivery as they possess a well-defined highly branched nanoscale architecture with many reactive surface groups. Their highly clustered surface groups allow for targeted drug delivery and high drug payload to enhance therapeutic effectiveness. This study presented a new type of polyionic hydrogels based on dendrimers with potential applications in drug delivery and tissue engineering. Polyethylene glycol (PEG) with various …

Balance Performance Measurment In A Phase Shifted Feedback Environment, Craig Alan Hoovler

Theses and Dissertations

Commercial technologies for the objective assessment of balance exist in clinical settings. Training requires integration of sensory information to produce a coordinated motor response related to balance. These systems have had measurable phase delays of up to 250ms in the visual feedback provided to the patient. This provokes an unnatural response, requiring prediction from the subject. The proposed research investigates the impact of visual feedback phase delays on the performance of weight shift tracking tasks in a population of individuals with no known balance deficits.Visual feedback delays were investigated by simulating popular balance training software which utilizes force plates to …

Electromyographic Characterization In An Animal Model Of Dystonia, Kunal Dilip Chaniary

Theses and Dissertations

Kernicterus causes damage to the auditory system and the basal ganglia in humans. Although the Gunn rat model of kernicterus has been extensively used to characterize the auditory features, this model has not been utilized to systematically investigate the movement disorder. In the present study, spontaneously jaundiced (jj) 16 day old Gunn rat pups were treated with sulfadimethoxine to exacerbate bilirubin neurotoxicity and compared to saline treated jjs and non-jaundiced (Nj) littermates. Electromyographic (EMG) activity was recorded from antagonistic hip muscles in dystonic and in normal appearing rats. Raw EMG signals were decomposed using the Discrete Wavelet Transform based multi-resolution …

Design Of An Electrospun Type Ii Collagen Scaffold For Articular Cartilage Tissue Engineering, Catherine Pemble Barnes

Theses and Dissertations

Traumatic defects in articular cartilage can lead to joint disease and disability including osteoarthritis. Because cartilage is unable to regenerate when injured, the field of tissue engineering holds promise in restoring functional tissue. In this research, type II collagen was electrospun, cross-linked, and tested as scaffolds for supporting chondrocyte growth. The mechanical, biochemical, and histological characteristics of the engineered tissue were assessed as a function of the electrospinning solution concentration (i.e. scaffold fiber diameter and pore properties) and as a function of the time in culture (evaluated at 2, 4, and 6 weeks). Fiber diameter had a linear relationship with …

Development And Validation Of A Computational Musculoskeletal Model Of The Elbow Joint, Justin Paul Fisk

Theses and Dissertations

Musculoskeletal computational modeling is a versatile and effective tool which may be used to study joint mechanics, examine muscle and ligament function, and simulate surgical reconstructive procedures. While injury to the elbow joint can be significantly debilitating, questions still remain regarding its normal, pathologic, and repaired behavior. Biomechanical models of the elbow have been developed, but all have assumed fixed joint axes of rotation and ignored the effects of ligaments. Therefore, the objective of this thesis was to develop and validate a computational model of the elbow joint whereby joint kinematics are dictated by three-dimensional bony geometry contact, ligamentous constraints, …

The Lynks Reader, Anne Marie Reamey

Theses and Dissertations

Many adults and children have problems reading and comprehending books, signs, written directions, etc. These same individuals have difficulty processing written materials as a result of right hemisphere interference. The Lynks Reader (DLR Co., Richmond, VA) is a commercially developed device which has been used to help individuals move from their right to their left hemisphere and to increase reading fluency and comprehension. The objective of this project was to evaluate the best way to use the various forms of the Lynks Reader. Using the device demonstrated an increase in reading fluency and comprehension by increasing the left hemisphere dominance. …

The Development Of A Multi-Directional Wear Apparatus And The Characterization And Correlation Of Biomechanical And Biotribological Properties Of Bovine Articular Cartilage, Kelly J. Shields

Theses and Dissertations

A multi-directional wear apparatus was developed to simulate the kinematic motion of diarthrodial joints. A comprehensive evaluation including biotribological and biomechanical characterization of articular surfaces was performed with concomitant translational and oscillating rotational motion similar to that experienced in vivo. Various system parameters were evaluated in the designed experiments including normal load magnitude (high/low), surface quality (defect/no defect), and wear pattern (with/without rotation). Biomechanical characterization was achieved through stress relaxation and dynamic cyclical testing. Quasi-linear viscoelastic theory was used to curve-fit the stress relaxation data, while the dynamic data was used to determine the dynamic properties through Fast Fourier Transform …

Computational Modeling To Predict Mechanical Function Of Joints: Validations And Applications Of Lower Leg Simulations, Peter C. Liacouras

Theses and Dissertations

Computational models of musculoskeletal joints and limbs can provide useful information about joint mechanics. Validated models can be used as a predictive device for understanding joint function and serve as a clinical tool for predicting the outcome of surgical procedures. A new computational modeling approach was developed for simulating joint kinematics that are dictated by bone/joint anatomy, ligamentous constraints, and applied loading.Three-dimensional computational models of the lower leg were created. Model development involved generating three-dimensional surfaces from CT images, followed by importing these surfaces into SolidWorks and COSMOSMotion. ThroughSolidWorks and COSMOSMotion, each bone surface was created into a solid object …

Detection, Identification And Classification Of Suck, Swallow And Breathing Activity In Premature Infants During Bottle-Feeding, Fedra Adnani

Theses and Dissertations

Prematurity, especially if extreme, is one of the leading causes of problems and/or death after delivery. Among all the problems encountered by premature infants, feeding difficulties are very common. Many premature infants are fed intravenously at first, and they progress to milk feedings provided by a tube passed into the stomach. At around 34 weeks of gestation, premature infants should be able to breastfeed or take a bottle. At the same time such premature infants are usually faced with difficulty making the transition from tube-feeding to full oral feeding. In this study three physiological measurements of premature infants including sucking, …

Evaluation Of Prototype Cell Delivery Catheters Using Agarose Gel And Cell Culture Experiments, Sagar Panse

Theses and Dissertations

Neurodegenerative diseases and brain tumors affect millions of patients worldwide and are associated with significant morbidity and mortality. The blood brain barrier constitutes a major obstacle to delivery of therapeutic agents administered systemically for treating these disorders. Intracranial drug delivery provides a novel way of bypassing the blood brain barrier and achieving high concentration of therapeutic agents in the brain while avoiding systemic side effects. However damage to tissues during insertion of catheters, release of air in the brain and consequent backtracking of dye are some disadvantages with this mode of treatment. We evaluated prototype cell delivery catheters (each with …

Hmg-Coa Reductase Inhibitors Act Synergistically With Ucn-01 Through Ras Inhibition, Payal Khanna

Theses and Dissertations

The primary objective of this study is to elucidate the mechanism by which the reagent UCN-01 induces apoptosis when administered to leukemia cells along with HmG-CoA reductase inhibitors, mainly the statins. In this study, we demonstrated that exposure of leukemia cell lines to lovastatin (20 uM, 18 hours) and UCN-01 (100 nM, 18 hours) resulted in mitochondria dysfunction, procaspase 3 and 9 cleavage, and PAW degradation along with marked cytochrome C release and apoptosis. Although similar molecular mechanisms have not yet been confirmed in other cancers, our hypothesis holds that enhanced apoptotic effects of UCN-01 are due in part to …

Design And Validation Of A Full Contact Gait Simulator For The Cadaveric Lower Extremity, Joseph Michael Iaquinto

Theses and Dissertations

The projects goal was to create a device to simulate full contact gait in the cadaveric lower extremity. The Contact Gait Simulation System loads specific muscles to recreate anatomical dorsi and plantar flexion of the ankle under axial loading. A system of pneumatic load generation was connected a LabVIEW virtual instrument (VI), which controlled the application of these loads. The loads were roughly based off literature cited EMG data, and further modified from feedback. In addition to controlling the load system, the VI also coordinates external sensor timing. Along with this simulator, software was developed specifically for analyzing pressure data …

Development Of A Software Application To Extract The Features Of Normal Respiratory Sounds From The Lungs And The Trachea, Ranjani Sabarinathan

Theses and Dissertations

Auscultation has been widely regarded as one of the most important noninvasive diagnostic tools for clinical diagnosis of the respiratory tract. The purpose of this thesis was to develop a software application capable of extracting the key features of respiratory sound signals from the lungs and trachea of healthy persons. The efficacy of the program was evaluated by the verification of the important features of the sound signals from the left and right lungs and the trachea such as 1) right and left lung symmetry and 2) dissimilarity between the trachea and both lungs. The program was developed in LabView …

Determination Of The Mechanical Properties Of Electrospun Gelatin Based On Polymer Concentration And Fiber Alignment, Leander Taylor Iii

Theses and Dissertations

The process of electrospinning has given the field of tissue engineering insight into many aspects of tissue engineered scaffolds, including how factors such as fiber diameter and porosity are affected by polymer concentration. However, the affects of fiber alignment upon the material properties of electrospun scaffolds remains unclear. The purpose of this study is to determine how the material properties of electrospun gelatin scaffolds are affected by changes in fiber alignment and starting gelatin concentration. Gelatin scaffolds, with starting concentrations of 80, 100, and 130mg/m1, were electrospun onto a target mandrel rotating at various speeds. Samples of each scaffold were …

Scaffold Permeability As A Means To Determine Fiber Diameter And Pore Size Of Electrospun Fibrinogen, Scott Allen Sell

Theses and Dissertations

The purpose of this study was to construct a flowmeter that could accurately measure the hydraulic permeability of electrospun fibrinogen scaffolds, providing insight into the transport properties of electrospun scaffolds while making the measurement of their topographical features (fiber and pore size) more accurate. Three different concentrations of fibrinogen were used (100, 120, and 150mg/ml) to create scaffolds with three different fiber diameters and pore sizes. The fiber diameters and pore sizes of the electrospun scaffolds were analyzed through scanning electron microscopy and image analysis software. The permeability of each scaffold was measured and used to calculate permeability-based fiber diameters …