Engineering Commons^™

Numerical Investigation Of Subglottal Stenosis Effects On Human Voice Production, Dariush Bodaghi

Electronic Theses and Dissertations

This dissertation aimed to advance knowledge of how subglottal stenosis impacts voice production physiology. An in-house fluid-structure-acoustic interaction approach based on the hydrodynamic/acoustic splitting technique was employed. This technique was rigorously verified for simulating phonation by matching the acoustic behavior to a compressible flow solver for phonation-relevant geometries. Simulations of an idealized 2D vocal tract model demonstrated the effects of supraglottal acoustic resonance on vocal fold kinematics and glottal flow waveform. Results showed that the acoustic coupling between higher harmonics and formats generated pressure oscillations, modifying vocal fold dynamics and glottal flow rate.

A major novelty was the incorporation and …

Longitudinal Case-Control Study Of Mammographic Breast Tissue Subtypes, Kendra Batchelder

Electronic Theses and Dissertations

Breast density is a known risk factor for breast cancer. However, there has been limited research on potential subtypes of mammographic dense breast tissue to identify areas of active dense tissue that is structurally reorganizing and links to cancer dynamics, versus areas of passive dense tissue which remains organized. We hypothesize that the amounts of subtypes of mammographic dense tissue and the associated rate of change through time could provide insights into breast cancer risk. A retrospective study was conducted to investigate breast cancer using longitudinal screening mammograms and accompanying pathology reports collected in 2015. Patients were matched by age …

Hybrid Power Spectral And Wavelet Image Roughness Analysis, Basel White

Electronic Theses and Dissertations

The Two-Dimensional Wavelet Transform Modulus Maxima (2D WTMM) sliding window methodology has proven to be a robust approach, in particular for the extraction of the Hurst (H) roughness exponent from grayscale mammograms. The power spectrum is a computational analysis based on the Fourier transform that can be used to estimate the roughness of a scale-invariant image or region via the calculation of H. We aim to examine how the calculation of H in fractional Brownian motion (fBm) images and mammograms can be improved. fBm images are generated for H ∈ [0.00,1.00] for testing through the previous 2D …

Development Of A New Method For Cell Spheroid Formation Through A Hydrogel Dipping Process, Aimee L. Co

Electronic Theses and Dissertations

Traditional cell culture systems make use of two-dimensional (2D) monolayer studies which are simple, cheap, and have been successful for a various cell types. However, since this does not reflect on the in vivo physiology, studies have branched out to use three-dimensional (3D) cell culture systems. 3D cell culture allows for studies which make use of the cell connectivity, polarity, and tissue architecture. The use of 3D aggregates called spheroids is one of the most common and versatile of these methods. There are various techniques for spheroid formation and chosen technique is often decided based on the decided spheroid use …

Segmentation And Statistical Analysis Of Imaged And Simulated 3d Chromosome Territories, Hannah Varney

Electronic Theses and Dissertations

With advances in microscopy in the 21st century, more accurate measurements of the morphology and position of chromosome territories (CTs) during interphase within the cell nucleus can be obtained. These measurements have determined that CTs are non-randomly positioned, and their position and shape can change during diseases like breast cancer, pancreatic cancer, and Huntington’s Disease. The 2.5D Wavelet Transform Modulus Maxima segmentation method uses multi-scale edge detection to accurately segment objects in 3D images to find variables such as surface area, volume, and diameter without assuming a spherical or ellipsoidal shape. Measurements of centroid distance, shell distance and radial distance …

Growth Of Perkinus Marinus By Bioreactor Fermentation, Caitlin Murphy

Electronic Theses and Dissertations

Perkinsus marinus is a marine protozoan responsible for “Dermo” disease in the eastern oyster species, Crassostrea virginica. P. marinus has been detected along the Atlantic Coast of the United States and Mexico. In laboratory studies, many parasites need to be maintained in vivo, which complicates the study of the organism. However, In vitro cell culture for P. marinus at a scale of 1 mL was established in 1993 by several groups with the 1995 optimization (Gauthier & Vasta, 1993, 1995) considered the gold standard for small scale growth of this species. In addition to its importance as a …

Nanocellulose Conduits For Enhanced Regeneration Of Peripheral Nerve Injuries, Nicklaus R. Carter

Electronic Theses and Dissertations

Peripheral neuropathy is estimated to afflict 20 million people in the United States. Most cases of neuropathy result from physical injuries and trauma arising from automobile accidents and war. Peripheral nerves have the intrinsic ability to regenerate over time, bridging the injury gap. However native regeneration is limited to a distance of only a few millimeters. Current methods utilized to assist in the regeneration of peripheral nerves over distances exceeding those amenable to native repair include nerve autografts and allografts, and implantation of conduits. Nerve autografts are regarded as the most effective method but require a second surgical site to …

Characterization Of Nano-Cellulose Based Composites For Biomedical Applications, Mitchell P. Chesley

Electronic Theses and Dissertations

The number of orthopedic surgeries performed globally has steadily increased over the past decade due to the standardization of procedures as well as technological advancements. During this time orthopedic devices have been composed predominantly of metals, such as Titanium, Vanadium, Molybdenum, and Stainless steel, as well as their alloys, due to the high strength and durability of these materials. However, metals may, in fact, be suboptimal for orthopedic devices. For example, metals exhibit Young’s modulus much greater than the surrounding bone, inducing localized stress-shielding promoting cortical atrophy, which can lead to osteoporosis. In recent years polymers have been successfully explored …

Design, Construction And Application Of A Home-Built, Two-Photon Microscope, William P. Breeding

Electronic Theses and Dissertations

Two-photon microscopy (TPM) is a powerful, versatile imaging modality for the study of biological systems. This thesis overviews the relevant physics involved in TPM, design considerations and process of constructing a home-built, two-photon microscope, and provides a set of procedures to operate the system. Furthermore, this work explores several applications of TPM through the study of single-cell metabolism and imaging the cellular-material interface. Explored in particular depth was the imaging of cellulose nanofiber (CNF) materials, with the goal of understanding the three-dimensional nature of fibroblast cell growth when embedded within the materials. This work uncovered several optical properties of CNF, …

An Automated Device To Increase Screening Throughput Of Zebrafish Larvae, Fuoad Saliou-Sulley

Electronic Theses and Dissertations

The use of the zebrafish as an animal model alternative to mammalian species has spawned research advancements in several medical fields. Since the zebrafish shares a high degree of sequence and functional homology with mammals, studies using this organism can provide in-depth insight into host response to disease and provide a platform for testing a range of treatment options. The optical transparency of zebrafish at early stages of development permits easy assessment of the effects of treatments, occurrence of tumors and other abnormal growth, disease progression, and immune response, to name only a few. These characteristics make it ideal for …

A Multi-Channel 3d-Printed Bioreactor For Evaluation Of Growth And Production In The Microalga Dunaliella Sp, Cristian A. Cox

Electronic Theses and Dissertations

We explored the capabilities of additive manufacturing using a photo-cured jetted material 3D printer to manufacture a milli-microfluidic device with direct application in microalgae Dunaliella sp growth and intracellular compounds biosynthesis tests. A continuous microbioreactor for microalgae culture was CAD designed and successfully built in 1 hour and 49 minutes using black photopolymer cured by UV and a support material. The microreactor was made up of 2 parts including the bioreactor itself and a microchannel network for culture media fluids and microalgae. Both parts were assembled to form a single unit. Additional optical and auxiliar components were added. An external …