Biomedical Engineering and Bioengineering Commons^™

Development Of An Application For Patient-Centered Dementia Care., David Collar Alston

Electronic Theses and Dissertations

Dementia care in the United States faces several challenges, many of them associated with managing the information that is associated with patients. Protected patient information about patients is often separated between many sources. For example, a new doctor may have information on patient medicines, but not the document associated with the caregiving goals of the patient and their family. Problems can develop if a patient is treated by a new caregiver, who may not know the patient’s treatment and behavior history. There is a strong desire for a system that can collect, organize, and analyze patient information in a user …

Pulsatile Flow Does Not Improve Efficacy In Ex Vivo Lung Perfusion., Keith A. Zoeller

Electronic Theses and Dissertations

Introduction Ex vivo lung perfusion (EVLP) has the potential to increase the donor pool for lung transplantation by facilitating extended evaluation of marginal organs. Current methodology employs continuous flow pumps for perfusion. In vivo, continuous flow has been shown to increase pulmonary vascular resistance (PVR). Thus, pulsatile flow EVLP may reduce PVR and improve organ preservation by providing physiologic flow morphology. Methods Lung blocks harvested from male, Yorkshire pigs were allocated into continuous (CF, n=3) and pulsatile flow (PF, n=4) groups. Lungs were ventilated at 4-5 mL/kg, 30% FiO2 and perfused with an acellular, albumin-based solution corrected for osmolarity, acid/base …

Development Of A Computational Approach To Assess Hip Fracture And Repair: Considerations Of Intersubject And Surgical Alignment Variability, Azhar Ali

Electronic Theses and Dissertations

Hip fracture remains a major public health concern due to the significant number of occurrences and mortality rates. Intertrochanteric fractures are the most common type of fracture and are typically caused by a fall. Intramedullary osteosynthesis is a common surgical practice to repair intertrochanteric fractures, but revisions are often required. The work presented in this thesis aims to improve the realism and fidelity of computational models of hip fracture, which can be an effective alternative to costly and labor-intensive clinical in-vivo and experimental in-vitro testing. Intersubject variability is inherently present in anatomy and material relations. Statistical shape and intensity models …

Computational Biomechanical Modeling Of The Human Knee During Kneeling, Tariq R. Abo-Alhol

Electronic Theses and Dissertations

Total knee replacement benefits patients who suffer from severe knee pain or joint stiffness and other joint related illnesses that limit everyday activities. There has been an increase in the number of procedures performed each year and a need to evaluate the performance of these implants during specialized activities such as kneeling. Most computational studies lack insight into inter-patient variability and the results do not apply to large population. This study developed: (1) three-dimensional explicit finite element (FE) models to investigate natural and implanted knee joint kinematics and bone strain and (2) a platform to enable population-based evaluation by combining …

Study Of Immobilizing Cadmium Selenide Quantum Dots In Selected Polymers For Application In Peroxyoxalate Chemiluminescence Flow Injection Analysis, Christopher S. Moore

Electronic Theses and Dissertations

Two batches of CdSe QDs with different sizes were synthesized for immobilizing in polyisoprene (PI), polymethylmethacrylate (PMMA), and low-density polyethylene (LDPE). The combinations of QDs and polymer substrates were evaluated for their analytical fit-for-use in applicable immunoassays. Hydrogen peroxide standards were injected into the flow injection analyzer (FIA) constructed to simulate enzyme-generated hydrogen peroxide reacting with bis-(2,4,6-trichlorophenyl) oxalate.

Linear correlations between hydrogen peroxide and chemilumenscent intensities yielded regression values greater than 0.9750 for hydrogen peroxide concentrations between 1.0 x 10^-4 M and 1.0 x 10^-1 M. The developed technique’s LOD was approximately 10 ppm. Variability of the prepared …

Modeling Hrtf For Sound Localization In Normal Listeners And Bilateral Cochlear Implant Users, Douglas A. Miller

Electronic Theses and Dissertations

Mathematical models can be very useful for understanding complicated systems and for testing algorithms through simulation that would be difficult or expensive to implement. This dissertation presents a model that attempts to simulate the sound localization performance of persons using bilateral cochlear implants. The expectation is that this model could prove to be a useful tool in developing new signal processing algorithms for neural encoding strategies.

The head related transfer function (HRTF) is a critical component of this model, and in the ideal case, provides the base characteristics of head shadow, torso and pinna effects. This defines the temporal, intensity …

Techno-Economic And Fluid Dynamics Analysis For Growing Microalgae With The Intent Of Producing Biofuel Using A System Model, Leah R. Raffaeli

Electronic Theses and Dissertations

Techno-economic and systems studies on microalgal growth scenarios to date are abbreviated and missing a number of important variables. By including these variables in a detailed model integrating biology, chemistry, engineering, and financial aspects, a more defined systems analysis is possible. Through optimizing the model productivity based on the resulting net profit, the system analysis results in a more accurate assessment of environmental and economic sustainability of specific algal growth scenarios. Photobioreactor algal growth scenario optimization in the system model has resulted in realistic engineering design requirements based on algal growth requirements and fluid dynamics analysis. Results show feasibility for …

Optimization Of Spray Droplet Size For Drug Delivery To The Deep Lung, Renee Worden

Electronic Theses and Dissertations

The lower respiratory regions of the lung boast over 900 million alveoli with a combined 85 m2 of surface area of near direct access to the bloodstream. Within the last century the immense potential of the deep lung as a site for the delivery of drugs has begun to be exploited and today pulmonary delivery of aerosolized therapeutic is commonplace. However, the high inter- and intra-patient variability in dosing is almost completely ignored. Currently, no steps are being taken to mitigate the sources of variability beyond injection into the upper airways. This study seeks to prove that a careful selection …

Biomechanical Comparison Of Lower Limb Unloading Between Common Modalities Of Ankle Foot Orthoses, Andrea Blake Wanamaker

Electronic Theses and Dissertations

Tibial stress fractures and other lower extremity injuries can be treated using an ankle foot orthosis (AFO). AFOs are popular because they allow the patient to ambulate somewhat naturally while reducing weight bearing on the injured limb. Despite their popularity, it is currently unclear how well AFOs reduce lower extremity weight bearing.

The first objective of this investigation was to examine the ability of three commonly used ankle foot orthoses to reduce weight bearing within the lower limb by comparing the ground reaction force measured from a force platform to the force measured from an insole pressure measurement device inside …

Computational Representation Of The Patellofemoral Joint, Abraham Wright

Electronic Theses and Dissertations

Many people suffer from knee pain due to abnormal function of the patellofemoral joint and are not able to enjoy normal activities of daily living. Surgical treatments are available and new methods are being developed by the medical industry. However, computational tools to efficiently evaluate the effects of the intervention on patellofemoral function are lacking.

Therefore, a validated and efficient computational model of the patellofemoral joint was developed. The subject specific finite element model was validated against the patellar kinematics recorded during cadaveric patellofemoral laxity experiments of the natural knee. The development involved a sequential process in which the soft-tissue …

Representing Intersubject Variability With A Statistical Shape And Alignment Model Of The Knee, Chandreshwar Rao

Electronic Theses and Dissertations

Prior statistical shape models have not considered multiple structures in the knee joint to characterize anatomic variation which are required to investigate joint mechanics further for the successful knee replacement. Accordingly, the study's objective was to develop statistical shape and alignment model (SSAM) to capture intersubject variability and demonstrate the ability to generate realistic instances for use in finite element analysis (FEA). SSAM described the variability in the training set of 20 subjects with a series of modes of variation obtained by performing principal component analysis (PCA). PCA produced modes of variation with the first 3 modes representing 70% and …

Explicit Finite Element Modeling Of The Human Lumbar Spine, Milind Rao

Electronic Theses and Dissertations

Validated finite element (FE) models of the functional spinal unit (FSU) and lumbar spine are essential in design-phase device development and in assessing the mechanics associated with normal spine function and degenerative disc disease (DDD), as well as the impact of fusion and total disc replacement (TDR). Although experimental data from fully intact specimens can be used for model calibration and validation, the contributions from the individual structures (disc, facets, and ligaments) may be inappropriately distributed. Hence, creation of decompression conditions or device implantations that require structure removal may not have the proper resulting mechanics. An explicit FE formulation may …

Pulmonary Particle Deposition In Relation To Age, Body Weight, And Species, Lisa M. Weber

Electronic Theses and Dissertations

As a result of dissimilarity in lung morphometry and physiological conditions, therapeutic aerosol particles deposit differently in humans of various ages and body weights. These particles also deposit differently in non-human species that are often utilized in inhalation and dosing studies. The focus of this work is to determine the optimal particle size and deposition (traditional efficiency and volume-weighted) of therapeutic particles in humans of both genders ranging in age from 3 months old to 21 years old and three non-human species (B6C3F₁ mouse, Long-Evans hooded rat, and Beagle dog). This study finds that in humans, both optimal …

Electrohydrodynamic Atomization For Improved Macromolecular Drug Delivery, Michelle Zeles-Hahn

Electronic Theses and Dissertations

With advances in drug research, the use of biological therapeutics is becoming a reality. Unfortunately, methods for processing and delivering these fragile macromolecules often limit their therapeutic potential. For this dissertation, we explore the aerosolization of macromolecules by way of electrohydrodynamic atomization (EHDA) and how this method can be used to process and deliver therapeutics. EHDA employs a high voltage to break a column of liquid into drops. It was unknown if or how the residual charge left of the resulting droplets would affect lung cells. An in vitro experiment was conducted to spray aerosolized DNA, by way of EHDA, …

Influence Of Compressible Aerogel Electrodes On The Properties Of An Electrochemical Cell, Chris Sponheimer

Electronic Theses and Dissertations

In the biomedical field the need for intra organ pressure measurement can only be facilitated by adapting existing pressure sensing technology to the specific tissues under test. The customization of these sensors has only driven up cost and the need to explore new technologies has become increasingly more important. For this dissertation, we explore the use of a new technology, particularly electrochemical pressure sensing to provide a low-cost pressure sensor to fill this need. Preliminary testing showed that electrically conductive polymers exhibited a change in voltage when pressurized if bubbles were first electrolyzed in the gel creating an aerogel, and …

Parametric Model Of Head Related Transfer Functions Based On Systematic Movements Of Poles And Zeros With Sound Location For Pole/Zero Models, Bahaa W. Al-Sheikh Hussein

Electronic Theses and Dissertations

Directional transfer functions (DTFs), the directional components of the Head Related Transfer Functions (HRTFs), are generally measured at finite locations in azimuth and elevation. Thus models are needed to synthesize DTFs at finer spatial resolution than the measured data to create complete virtual auditory displays. In this research, minimum-phase all-pole and all-zero models were used for modeling both human and cat DTFs. Real cepstrum analysis has been used to represent minimum phase HRTFs in the time domain. For the human DTFs, model orders were chosen to achieve specific objective error criteria published in previous studies that were based on subjective …

A Computer Science Approach To Identify And Classify Hyperactivated Spermatozoa, Norbert Kaula

Electronic Theses and Dissertations

Effective Assisted Reproductive Technology (ART) relies in part upon accurate but easily conducted measurements of sperm motion parameters. Several established methods are widely used to assess possible reasons for male infertility, in human and veterinary Andrology clinics. Computer-assisted sperm analysis (CASA) devices quantitatively assess sperm motion parameters, which have been defined by the World Health Organization, and include the percentage of motile cells in a sample and the motion characteristics of individual cells, such as curvilinear velocity (VCL), average path velocity (VAP) and straight line velocity (VSL). However, CASA analyses fail to define hyperactive sperm motility or determine the prevalence …

A Model For Electrical Communication Between Cochlear Implants And The Brain, Douglas A. Miller

Electronic Theses and Dissertations

In the last thirty years, cochlear implants have become an invaluable instrument in the treatment of severe-to-profound hearing impairment. An important aspect of research in the continued development of cochlear implants is the in vivo assessment of signal processing algorithms intended to improve perception of speech and other auditory signals. In trying to determine how closely cochlear implant recipients process sound relative to the processing done by a normal auditory system, various assessment techniques have been applied. The most common technique has been measurement of auditory evoked potentials (AEPs), which involves the recording of neural responses to auditory stimulation. Depending …

Generation Of Recombinant Mouse Embryonic Stem Cell Lines And Theirapplication For In Vivo Bioluminiscence Imaging In The Heart, Ramana Kammili

Electronic Theses and Dissertations

Cardiovascular disease is the major cause of death in the United States, with 80 million people suffering from some form of heart disease each year. One major limitation is the inability of the heart to repair the damaged tissue. Stem cell therapy holds enormous promise to repair and regenerate the damaged myocardium, but there are many technical difficulties that must first be overcome. One such difficulty is the present lack of ability to track and assess transplanted stem cells over time in vivo. The central hypothesis of this thesis is that in vivo bioluminescence imaging is a safe and useful …

Mems Transducer For Hearing Aid Device, Houwen Tang

Electronic Theses and Dissertations

A study of implantable middle ear MEMS piezoelectric transducer for hearing aids was developed. The physical vibration deflection at the tip of the transducer is simulated using finite element method. Further, a study of thermoelastic damping effect of four designed MEMS mirrors used as resonators is presented. An optical measurement system based on Mach-Zehnder interferometer is

Nitric Oxide Production: A Mechanism For Inhibition Of Chlamydia Trachomatis Replication, Bojun Chen

Electronic Theses and Dissertations

Chlamydia trachomatis (CT) replicates in macrophages, but is inhibited by IFN-$\gamma$ or LPS. IFN-$\gamma$ and/or LPS induced nitrite production in mouse peritoneal macrophages, macrophage cell lines (RAW264.7 and J774A.1) and McCoy cells. Kinetic studies indicated that peak production occurred 48 hours post-treatment. CT infection itself was insufficient to induce nitrite production, but resulted in enhancement of nitrite production in IFN-$\gamma$-treated cells. Treatment with IFN-$\gamma$ or LPS resulted in significant inhibition of CT replication in these cells. Strong correlation between nitrite production and inhibition of CT replication was observed in RAW264.7 and J774A.1 cells (correlation coefficients: $-$0.93 and $-$0.94, p $<$ 0.001). N$\sp{\rm g}$- monomethyl-L-arginine (L-NMMA) specifically inhibited nitrite production and partially reversed inhibition of CT replication in macrophage cell lines. NOS mRNA was measured in RAW264.7 cells by Northern blot and Dot blot hybridization. Strong correlation between NOS mRNA expression and inhibition of CT replication (correlation coefficient: $-$0.97, p $<$ 0.05) was observed. Anti-TNF-$\alpha$ antibody completely neutralized the biological activity of TNF-$\alpha$ secreted by LPS-treated RAW264.7 cells, yet the antibody neither reduced nitrite production nor restored CT replication. Combination of the antibody and L-NMMA significantly enhanced restoration of CT replication. In peritoneal macrophages, inhibition of CT replication induced by IFN-$\gamma$ was partially restored by L-NMMA or anti-TNF-$\alpha$ antibody. In McCoy cells, inhibition of CT replication induced by IFN-$\gamma$ and LPS was not significantly restored by L-NMMA. Great restoration of CT replication by 1 mM L-NMMA was observed in LPS-treated J774A.1 cells (31%), but not in IFN-$\gamma$-treated cells (5%). Our data indicate that (1) NO production is one of the mechanisms for inhibition of CT replication in IFN-$\gamma$-activated peritoneal macrophages and RAW264.7 cells; (2) NO plays a significant role in CT inhibition in LPS-treated macrophage cell lines, but not peritoneal macrophages; (3) TNF-$\alpha$ may be associated with inhibition, but the mechanism(s) may not involve NO production; (4) NO production may not be the mechanism for CT inhibition in McCoy cells treated with IFN-$\gamma$ and LPS.

Metabolism Of Arachidonate-Containing Phospholipid Molecular Species In The Murine Macrophage-Like Cell Line, P388d1, Crystal R. Waites

Electronic Theses and Dissertations

Glycerophospholipids of mammalian cells exist as chemically diverse structures with various fatty acids at the sn-1 and sn-2 positions. Arachidonic acid, a polyunsaturated fatty acid, which may be converted to biologically active eicosanoids such as prostaglandins, thromboxanes, and leukotrienes, is found predominantly in the sn-2 position of glycerophospholipids. The purpose of this study was to examine, at the level of the individual molecular species, the incorporation of arachidonate into phospholipids and its release from phospholipids during stimulation. In this way, the specificity of the enzymes controlling arachidonate metabolism could be examined in order to clarify the processes that control the …