Engineering Commons^™

Plantar Measurements To Determine Success Of Surgical Correction Of Stage Iib Adult Acquired Flatfoot Deformity, Erika Matheis

Theses and Dissertations

Adult Acquired Flatfoot Deformity (AAFD) is a progressive disease characterized by mechanical degeneration of the soft tissue structure in the arch of the foot that leads to changes in joint alignment. Surgical intervention commonly via tendon transfer and bony osteotomy is used to restore arch architecture, however there is a lack of quantitative assessments that measure the success of the surgical correction in vivo. Using plantar pressures via Tekscan® HR Mat and surveys (SF-36, FAOS), pre-operative and post-operative measures for six participants were defined, analyzed and compared. A paired t-test showed significant lateral shift for percent body weight during walking …

Dc And Microwave Analysis Of Gallium Arsenide Field-Effect Transistor-Based Nucleic Acid Biosensors, John K. Kimani

Theses and Dissertations

Sensitive high-frequency microwave devices hold great promise for biosensor design. These devices include GaAs field effect transistors (FETs), which can serve as transducers for biochemical reactions, providing a platform for label-free biosensing. In this study, a two-dimensional numerical model of a GaAs FET-based nucleic acid biosensor is proposed and simulated. The electronic band structure, space charge density, and current-voltage relationships of the biosensor device are calculated. The intrinsic small signal parameters for the device are derived from simulated DC characteristics and used to predict AC behavior at high frequencies.

The biosensor model is based on GaAs field-effect device physics, semiconductor …

Accelerating Mri Data Acquisition Using Parallel Imaging And Compressed Sensing, Haifeng Wang

Theses and Dissertations

Magnetic Resonance Imaging (MRI) scanners are one of important medical instruments, which can achieve more information of soft issues in human body than other medical instruments, such as Ultrasound, Computed Tomography (CT), Single Photon Emission Computed Tomography (SPECT), Positron Emission Tomography (PET), etc. But MRI's scanning is slow for patience of doctors and patients. In this dissertation, the author proposes some methods of parallel imaging and compressed sensing to accelerate MRI data acquisition. Firstly, a method is proposed to improve the conventional GRAPPA using cross-sampled auto-calibration data. This method use cross-sampled auto-calibration data instead of the conventional parallel-sampled auto-calibration data …

Development Of A Closed-Loop Force Reduction Mechanism In A Gait Rehabilitation Device, Jeffrey Frankart

Theses and Dissertations

Elliptical trainers are prescribed in rehabilitative exercise but difficult to implement in populations with significant functional gait deficits. Typical elliptical machines do not mimic normal gait and therefore require modifications for clinical rehabilitation. This research builds on previous modifications of an elliptical trainer designed to simulate level-surface walking. This design differed from a commercial version. It included articulated footplates and an electromechanically-driven virtual-cam to control footplate position. Ankle dorsiflexion elicited lower-extremity muscle spasticity which produced an unwanted gait variant during stroke patient testing. Spasticity is a hyperexcitable stretch reflex causing inefficient gait. This project’s purpose was to develop an autonomous …

A Study Towards Development Of An Automated Haptic User Interface (Ahui) For Individuals Who Are Blind Or Visually Impaired, Ravi Rastogi

Theses and Dissertations

An increasing amount of information content used in schools, work and everyday living is being presented in graphical form, creating accessibility challenges for individuals who are blind or visually impaired, especially in dynamic environments, such as over the internet. Refreshable haptic displays that can interact with computers can be used to access such information tactually. Main focus of this study was the development of specialized computer applications allowing users to actively compensate for the inherent issues of haptics when exploring visual diagrams as compared to vision, which we hypothesized, would improve the usability of such devices. An intuitive zooming algorithm …

Piezoelectric Probes And Their Capacity To Monitor Time Varying Viscosity, Eman Ahmed

Theses and Dissertations

Real-time, bedside observation of patient clotting is essential in various surgeries in the operating room (OR), but specifically during cardiac surgeries. The objective of this thesis is to design and test a new piezoelectric device that can be used for viscoelasticity measurement with time as a Point of Care (POC) test. Slow turnaround times (TAT) of current methods to monitor blood viscoelastic changes in patients have led to excessive bleeding and the need for blood transfusions in many situations (Despotis et al, 1997). This study shows that the phase shift produced by a resonator sensor can be related to the …

Integrated Fiber Electrospinning: Creating Spatially Complex Electrospun Scaffolds With Minimal Delamination, Casey Grey

Theses and Dissertations

Tissue engineering scaffolds come in many shapes and sizes, however, due to difficulty manufacturing the microstructure architecture required in tissue engineering, most scaffolds are architecturally non-dynamic in nature. Because the microstructural architecture of all biological tissues is inherently complicated, non-dynamic tissue engineering scaffolds tend to be a poor platform for tissue regeneration. The current method for manufacturing dynamic tissue engineering scaffolds involves electrospinning successive layers of different fibers, an approach that exhibits no fiber transition between layers and subsequent delamination problems. In this study we aim to address the design challenges of tissue engineering scaffolds through our novel integrated fiber …

Preparation And Characterization Of A Self-Crimp Side-By-Side Bicomponent Electrospun Material, Yang Han

Theses and Dissertations

Bicomponent composite fibers have been widely used in the textile industry and are gaining increasing attention on biomedical applications. In this research, polycaprolactone/poly (lactic acid) side-by-side bicomponent fibers were created for the application of a biodegradable scaffold. The side-by-side structure endowed the fiber with self-crimps when it was processed under certain conditions. This material was produced by electrospinning and collected on a high speed rotating mandrel to get highly oriented fibers. A mechanical stretch at the same direction was done followed by a wet heat treatment for polymer retraction. Crimped fibers were demonstrated by scanning electron microscopy. The quantitative porosity …

Optical Cryoimaging Of Celular Redox In Kidneys From Diabetic Mice, Sepideh Maleki

Theses and Dissertations

Diabetic Nephropathy (DN) is the major single cause of end stage renal diseases (ESRD) in the United States. Diabetes is the third leading fatal disorder after cancer and heart disease. It is affecting 8.3% of the residents of the United States, with a total healthcare cost of $174 billion/yr by 2010.

There currently exists a need for a sensitive and specific diagnosis for temporal detection of oxidative stress (OS) in cellular metabolic levels, which plays an early role in the development of DN. The objective of this research is to use a fluorescence optical imaging technique in order to delineate …

A Novel Method For Determining Acetabular Orientation, Sean Higgins

Theses and Dissertations

Enhanced knowledge of the acetabulum is of paramount importance in the diagnostic, planning, and execution stages of procedures and treatments targeting the hip joint. The convoluted and highly variable morphology of the structures comprising the bony pelvis make ascertaining measures of the acetabulum challenging. Furthermore, current methods for determining acetabular orientation assume symmetry between the separate halves of the pelvis by utilizing a coordinate system based on bilateral landmarks. The purpose of this study was to determine the three-dimensional orientation of the entire acetabulum. For this research, an improved programmatic method was developed for determining acetabular orientation using three-dimensional data. …

The Effect Of A Navigational Aid On Training Of A Minimally Invasive Surgery Camera Task, Ketan Vidwans

Theses and Dissertations

Minimally Invasive Surgery (MIS) differs from Open Surgery as surgeons view the surgical site indirectly on a monitor. The view shown is typically from an angled endoscope off to one side of the surgery (i.e., uncollocated with the view of the hands). This makes camera navigation a challenging ability to learn. MIS thus requires longer training periods, more practice and mental effort to achieve proficiency. Current training setups and Operating Room (OR) environments lack appropriate real-time visual cues for navigation and other perception related information that could help with learning and performance in the OR. The purpose of this research …

Evaluation Of A Novel Myoelectric Training Device, Ryan Clingman

Theses and Dissertations

While research shows that a patient’s success in using a myoelectric prosthetic arm is dependent on receiving effective training, current methods of training are not designed to effectively hold attention long enough for optimal training. This study focused on evaluating a novel myoelectric training device, consisting of a toy car controlled by EMG signals from the arm. Subjects’ performance with the trainer was evaluated to determine its ability to provide experience with EMG controls. Eight healthy adult subjects were taken through typical initial stages of myoelectric training, then asked to drive the car through a slalom course while the time, …

Life History Switch Point Plasticy In Response To Pond Drying Alyers Metamorph Allometry And Jumping Performance, Julie Charbonnier

Theses and Dissertations

Animals with complex life cycles can cope with environmental uncertainty by altering life history switch points through developmental plasticity. Pond drying is an important factor which may alter life history switch points in aquatic organisms. Many amphibians can plastically respond to changes in pond drying by emerging earlier, but few studies have examined the post-metamorphic consequences for performance. To investigate the potential carry-over effects of plasticity to pond drying, we studied the túngara frog, Physalaemus pustulosus, a tropical anuran that breeds in highly ephemeral habitats. We conducted a field study with three different water depth treatments in 60 L mesocosms …

Development Of A Multiple Contact Haptic Display With Texture-Enhanced Graphics, David Burch

Theses and Dissertations

This dissertation presents work towards the development of a multiple finger, worn, dynamic display device, which utilizes a method of texture encoded information to haptically render graphical images for individuals who are blind or visually impaired. The device interacts directly with the computer screen, using the colors and patterns displayed by the image as a means to encode complex patterns of vibrotactile output, generating the texture feedback to render the image. In turn, the texture feedback was methodically designed to enable parallel processing of certain coarse information, speeding up the exploration of the diagram and improving user performance. The design …

Optimization Of Feature Selection In A Brain-Computer Interface Switch Based On Event-Related Desynchronization And Synchronization Detected By Eeg, Mason Montgomery

Theses and Dissertations

There are hundreds of thousands of people who could benefit from a Brain-Computer Interface. However, not all are willing to undergo surgery, so an EEG is the prime candidate for use as a BCI. The features of Event-Related Desynchronization and Synchronization could be used for a switch and have been in the past. A new method of feature selection was proposed to optimize classification of active motor movement vs a non-active idle state. The previous method had pre-selected which frequency and electrode to use as electrode C3 at the 20Hz bin. The new method used SPSS statistical software to determine …

Finite Element Analysis Of Transverse Medial Malleolar Fracture Fixation, Ruchi Chande

Theses and Dissertations

Injury to the medial malleolus, the distal end of the tibia and one of the bones comprising the ankle joint, can occur in various loading scenarios. Open reduction/internal fixation (ORIF) to reattach the malleolar fragment to the proximal tibia can be achieved via various devices, however small fragments are particularly challenging to treat. In this study, computational finite element analysis (FEA) was utilized to investigate the fixation of transverse medial malleolar fractures by two cancellous screws or by a new fixation device, the Medial Malleolar Sled™. Cadaveric testing assessed the performance of the two constructs in both tension and torsion. …

Brain Controlled Switch, Dimple Bhuta

Theses and Dissertations

This study aims at designing and implementing a single channel stand-alone Brain-Controlled Switch (BCS) device, which records the electroencephalography (EEG) signals from the scalp using electrodes, amplifies it, eliminates interferences (associated with the EEG signals) and processes the EEG signals to extract and decode temporal signal features to determine user’s intention of regulating an external switch. The design of our “brain-controlled switch” device is implemented using a bio-potential amplifier and a microcontroller. The bio-potential amplifier amplifies the EEG signals to a level sufficient for processing, eliminates interferences and ensures patient safety. The microcontroller (dsPIC30F4013) digitizes the amplified and conditioned analog …

Quantification Of Preterm Infant Feeding Coordination: An Algorithmic Approach, Pallavi Ramnarain

Theses and Dissertations

Oral feeding competency is a primary requirement for preterm infant hospital release. Currently there is no widely accepted method to objectively measure oral feeding. Feeding consists primarily of the integration of three individual feeding events: sucking, breathing, and swallowing, and the objective of feeding coordination is to minimize aspiration. The purpose of this work was to quantify the infant feeding process from signals obtained during bottle feeding and ultimately develop a measure of feeding coordination. Sucking was measured using a pressure transducer embedded within a modified silicone bottle block. Breathing was measured using a thermistor embedded within nasal cannula, and …

In Vivo Immunotoxicological Evaluation Of Electrospun Polycaprolactone (Epcl) And Investigation Of Epcl As A Drug Delivery System For Immunomodulatory Compounds, Colleen Mcloughlin

Theses and Dissertations

Electrospun materials have potential use in many biomedical applications such as soft tissue replacements or as scaffolds to target drug delivery to local sites. Electrospinning is a polymer processing technique that can be used to create materials composed of fibers with diameters ranging from the micron to the nanoscale. We investigated the effects of microfibrous and nanofibrous electrospun polycaprolactone (EPCL) on innate, cell-mediated, and humoral components of the immune system. Results demonstrated that in both young (12 week) and old (6 month) mice, EPCL had no effect on various immune parameters. With its lack of immunotoxicity, EPCL presents an excellent …

Non-Invasive Intracranial Pressure Method And Monitor, Tarun Sinha

Theses and Dissertations

The eyes are acoustically continuous with the brain and inner ear tissues in regard to matched impedances, based on tissue densities, thus, vibration of one site will be reflected in all sites. With this being the case, the vibrational energy response of the eye due to an external source can be used to determine a correlation or draw a conclusion concerning the vibrational energy response of the brain would be. And since there is a correlation between the vibrational energies, any changes in the acoustical energy in the eye can possibly be used to determine the changes in acoustical energy …

Engineering Of Polyamidoamine (Pamam) Dendrimers For Gene And Drug Delivery, Quan Yuan

Theses and Dissertations

Dendrimers are a class of polymers with a highly branched, three-dimensional architecture composed of an initiator core, several interior layers of repeating units and multiple surface groups. They have been recognized as the most versatile compositionally and structurally controlled nanoscale building blocks throughout the fields of engineering, materials science, chemistry, and biology, and they have been widely investigated for drug and gene delivery. Polyamidoamine (PAMAM) dendrimers have inherent properties for gene delivery because of their high buffering capacity, polycationic surface and numerous surface groups for biofunctionlization. This dissertation is organized into four independent sections. The first section investigates a series …

Synthesis And Characterization Of Doxorubicin Carrying Cetuximab-Pamam Dendrimer Bioconjugates, Gunjan Saxena

Theses and Dissertations

A tumor targeted dendrimer based drug delivery system was designed and synthesized to carry chemotherapy drug doxorubicin. Polyamidoamine (PAMAM) dendrimer G4.5 was chosen as the underlying carrier. Anionic G4.5 is a good option for drug delivery as it consists of 128 surface groups, is less cytotoxic and favorably biodistributed. The delivery system was synthesized using a layer-by layer arrangement of three functional entities: chemotherapy drug doxorubicin, monoclonal antibody Cetuximab against EGF receptor, and polyethylene glycol (PEG). Doxorubicin was attached via an acid-sensitive hydrazon linkage to the dendrimer. Macromolecules are taken in by cells through endocytosis. pH inside the early endosomes …

Electroencephalography (Eeg)-Based Brain Computer Interfaces For Rehabilitation, Dandan Huang

Theses and Dissertations

Objective: Brain-computer interface (BCI) technologies have been the subject of study for the past decades to help restore functions for people with severe motor disabilities and to improve their quality of life. BCI research can be generally categorized by control signals (invasive/non-invasive) or applications (e.g. neuroprosthetics/brain-actuated wheelchairs), and efforts have been devoted to better understand the characteristics and possible uses of brain signals. The purpose of this research is to explore the feasibility of a non-invasive BCI system with the combination of unique sensorimotor-rhythm (SMR) features. Specifically, a 2D virtual wheelchair control BCI is implemented to extend the application of …

Semi-Interpenetrating Nanofiber Scaffolds For Transbuccal Drug Delivery, Donald Aduba Jr.

Theses and Dissertations

The oral buccal mucosa is a promising absorption site for drug administration because it is permeable, highly vascularized and allows ease of administration. Although there are many platforms that have been used for drug delivery, nanofiber scaffolds as a platform for local or systemic drug delivery through the oral mucosa have not been fully explored. In this thesis, we fabricated a biocompatible electrospun gelatin nanofiber scaffold for local drug delivery at the oral mucosa. To stabilize the electrospun gelatin nanofibers and allow non-invasive incorporation of therapeutics into the scaffold, photo-reactive polyethylene-glycol (PEG)-diacrylate was employed to crosslink the scaffold to form …

Three Dimensional In Vitro Model Of Head And Neck Squamous Cell Carcinoma, Anna Bulysheva

Theses and Dissertations

Head and neck squamous cell carcinomas (HNSCC) are among the leading causes of cancer related deaths throughout the world. The survival rate for this type of cancer is extremely low and has not changed significantly in recent decades. There is an imperative need to study tumor progression in a representative model in order to generate more knowledge about this disease as well as develop more effective treatment options. Multiple methods already exist for studying HNSCC and other types of cancers, including in vitro and in vivo models. Although in vivo models are more representative of the human carcinomas in terms …

Determination Of Effective Training Methods To Learn A Laparoscopic Camera Navigation Task Under Stressful Environments, Devnath Vasudevan

Theses and Dissertations

Stress in surgical environment is generally very high and can result in performance degradation increasing patient risk .Current Training systems for learning minimally invasive surgical skills do not consider the component of stress in their training model. In this study the focus was on developing alternative training models that would allow the learner to effectively perform minimally invasive skill under stress. Two alternate training methods: 1) Training under stress until high performance levels and 2) training until high performance and low cognitive load are achieved were considered for this study. The control group consisted of training under no stress and …

Regeneration Of Electrospun Bioresorbable Vascular Grafts: A Phenomenon Associated With Vascular Graft Properties And Macrophage Phenotypes (M1/M2), Koyal Garg

Theses and Dissertations

Macrophages (MФ) and mast cells are important cell types in the context of tissue remodeling and regeneration. Mast cells participate in the early stages of wound healing and modulate the acute inflammatory responses to biomaterials. Mast cells can secrete a myriad of different cytokines by the process of degranulation; the process of regulated secretion in which preformed contents stored in their granules are rapidly released by exocytosis. Some of these cytokines such as IL-4, IL-13 and TNF-α can modulate the MФ phenotype. Macrophages (MΦ) are innate immune cells, crucial for tissue homeostasis, presentation of foreign and self-antigens following infection/injury, pathogen …