Biomedical Engineering and Bioengineering Commons^™

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 …

Gait Rehabilitation Using Functional Electrical Stimulation Induces Changes In Ankle Muscle Coordination In Stroke Survivors: A Preliminary Study, Jessica L. Allen, Lena H. Ting, Trisha M. Kesar

Faculty & Staff Scholarship

No abstract provided.

Design And Evaluation Of A 3d Printed Filar Micrometer, Emily M. Rull

ELAIA

Background Double stars are celestial objects that allow for calculating the mass of stars by assessing their orbits. Stellar mass affects every current model of stellar evolution, but the most accurate double star orbits can take decades to record. Due to the long-term nature of such observations and lack of groundbreaking research in double star studies, professional astronomers are no longer focused on making these measurements, so amateur astronomers can pick up where professionals have left off. Amateurs can only do this if they can get the equipment that they need at prices they can afford. A personally-manufactured filar micrometer …

Effect Of Strong Electrolyte Containing Gelling Aids On The Sol-Gel Transition Temperature Of Hypromellose 2910, Elnaz Sadeghi

Biomedical Engineering ETDs

Hypromellose, or hydroxypropyl methylcellulose (HPMC) - has been widely used for biomedical and pharmaceutical applications due to its advantages, including that it is modifiable in terms of viscosity, and it has the ability to form thermally reversible hydrogels. The thermal gelation temperature (T_Gel) of a given HPMC solution strongly depends on its characteristic grade and the solution concentration. Applying certain additives can modify the T_Gel even further; depending on their nature and concentration. With the addition of said additives, a lower or higher T_Gel can be obtained. For example, the addition of sodium chloride (NaCl) reduces …

Investigating Cyanobacteria Metabolism And Channeling-Based Regulations Via Isotopic Nonstationary Labeling And Metabolomic Analyses, Mary Helen Abernathy

McKelvey School of Engineering Theses & Dissertations

Cyanobacteria have the potential to be low-cost and sustainable cell factories for bio-products; however, many challenges face cyanobacteria as biorefineries. This dissertation seeks to advance non-model photosynthetic organisms for biotechnology applications by characterizing central carbon metabolism and its regulations. Cyanobacteria phenotypes for bio-production are examined and their intracellular metabolism is quantified. Using isotopic labeling experiments, phenotypic relationships between biomass composition, central carbon fluxes, and metabolite pool sizes are investigated. Metabolic analyses of cyanobacteria led to new investigations of flux regulation mechanisms via protein spatial organizations or metabolite channeling. Metabolite channeling is further explored as a hypothesis to explain enigmatic labeling …

Kcnq1/Kcne1 Interaction In The Cardiac Iks Channel And Its Physiological Consequences, Jiajing Xu

McKelvey School of Engineering Theses & Dissertations

Dynamic conformational changes of ion channel proteins during activation gating determine their function as carriers of current. The relationship between these molecular movements and channel function over the physiological timescale of the action potential (AP) has not been fully established due to limitations of existing techniques. We constructed a library of possible cardiac IKs protein conformations and applied a combination of protein segmentation and energy linearization to study this relationship computationally. Simulations reproduced the effects of the beta-subunit (KCNE1) on the alpha-subunit (KCNQ1) dynamics and function, observed in experiments. Mechanistically, KCNE1 increased the probability of “visiting” conducting pore conformations on …

Molecular Basis Of Class Ib Drug Interactions With The Nav Channel Macromolecular Complex: A Route To Personalized Medicine For Cardiac Arrhythmia, Wandi Zhu

McKelvey School of Engineering Theses & Dissertations

The heart rhythm is precisely controlled by the electrical impulse that propagate in the cardiac tissue. In single cardiomyocytes, the electrical activity generated by action potentials (AP). Cardiac NaV channels (NaV1.5) carry a large influx of Na+ that mediates the initiation and propagation of the AP in both atria and ventricles. Disruption of NaV1.5 function by genetic variants or external factors can result in deadly arrhythmias, such as long QT syndrome and Brugada syndrome. Thus, NaV channels are import therapeutic targets. The class I antiarrhythmics are the modulators of the NaV channels. Although they have been used clinically for over …

Basis Vector Model Method For Proton Stopping Power Estimation Using Dual-Energy Computed Tomography, Shuangyue Zhang

McKelvey School of Engineering Theses & Dissertations

Accurate estimation of the proton stopping power ratio (SPR) is important for treatment planning and dose prediction for proton beam therapy. The state-of-the-art clinical practice for estimating patient-specific SPR distributions is the stoichiometric calibration method using single-energy computed tomography (SECT) images, which in principle may introduce large intrinsic uncertainties into estimation results. One major factor that limits the performance of SECT-based methods is the Hounsfield unit (HU) degeneracy in the presence of tissue composition variations. Dual-energy computed tomography (DECT) has shown the potential of reducing uncertainties in proton SPR prediction via scanning the patient with two different source energy spectra. …

Radiolabeled Nanohydroxyapatite As A Platform For The Development Of New Pet Imaging Agents, Stacy Lee Queern

Arts & Sciences Electronic Theses and Dissertations

Positron emission tomography (PET) imaging utilizes drugs labeled with positron emitters to target and evaluate different biological processes occurring in the body. Tailoring medicine to the individual allows for higher quality of care with better diagnosis and treatment and is a key purpose for advancing research into developing new platforms for PET imaging agents. A PET nuclide of high interest for the development of these agents is 89Zr. This can be attributed to the long half-life of 3.27 days and low positron energy of 89Zr.

In this work, we developed a production method for 89Zr using Y sputtered coins that …

Biodegradable And Biocompatible Silk Fibroin For Optical Applications, Corey Bryce Malinowski

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study presents nanopatterned silk fibroin films that were fabricated using soft lithography and nanoimprinting to replicate patterns from diffraction gratings. These film’s optics were analyzed based on their light scattering potential as well as their transmittance and transmission haze using a laser light, spectrometer, and UV-Vis spectrophotometer, respectively. The patterned fibroin films all displayed similar light scattering patterns to their master patterns with some transmission haze. When using the spectrometer to measure samples, those made without any nanostructure displayed transmission of 90% and over, while those with patterns depended on the structure used. The denser a structure, like the …

Chemically Modified Monolayer Surfaces Influence Valvular Interstitial Cell Attachment And Differentiation For Heart Valve Tissue Engineering, Matthew N. Rush

Nanoscience and Microsystems ETDs

As a cell mediated-process, valvular heart disease (VHD) results in significant morbidity and mortality world-wide. In the US alone, valvular heart disease VHD is estimated to affect 2.5% of the population with a disproportionate impact on an increasing elderly populous. It is well understood that the primary driver for valvular calcification is the differentiation of valvular interstitial cells (VICs) into an osteoblastic-like phenotype. However, the factors leading to the onset of osteoblastic-like VICs (obVICs) and resulting calcification are not fully understood and a more complete characterization of VIC differentiation and phenotypic change is required before treatment of valve disease or …

Towards An In Vitro Model Of Testing Osteoblast Cellular Function In Contact With Various Surfaces, Raheleh Miralami

Theses & Dissertations

Past studies have shown that the success of total joint replacements depends on the biocompatibility of orthopaedic materials, which can be improved by modifying the implant surface. However, the exact roles of these modifications and their effective mechanisms are poorly understood. The objective of this study was to develop and evaluate a model system to investigate the impact of nano-structured surfaces, produced by the ion beam-assisted deposition (IBAD) technique, on biomarkers of osteointegration using an in vitro model. The IBAD technique was employed to deposit zirconium oxide (ZrO₂), Titanium oxide (TiO₂), and Titanium (Ti) nano-films on …

Virtual Reality Simulation Of Glenoid Reaming Procedure, Mohammadreza Faieghi

Electronic Thesis and Dissertation Repository

Glenoid reaming is a bone machining operation in Total Shoulder Arthroplasty (TSA) in which the glenoid bone is resurfaced to make intimate contact with implant undersurface. While this step is crucial for the longevity of TSA, many surgeons find it technically challenging. With the recent advances in Virtual Reality (VR) simulations, it has become possible to realistically replicate complicated operations without any need for patients or cadavers, and at the same time, provide quantitative feedback to improve surgeons' psycho-motor skills. In light of these advantages, the current thesis intends to develop tools and methods required for construction of a VR …

Manganese-Enhanced Magnetic Resonance Imaging: Overview And Central Nervous System Applications With A Focus On Neurodegeneration, Ryan A. Cloyd, Shon A. Koren, Jose F. Abisambra

Physiology Faculty Publications

Manganese-enhanced magnetic resonance imaging (MEMRI) rose to prominence in the 1990s as a sensitive approach to high contrast imaging. Following the discovery of manganese conductance through calcium-permeable channels, MEMRI applications expanded to include functional imaging in the central nervous system (CNS) and other body systems. MEMRI has since been employed in the investigation of physiology in many animal models and in humans. Here, we review historical perspectives that follow the evolution of applied MRI research into MEMRI with particular focus on its potential toxicity. Furthermore, we discuss the more current in vivo investigative uses of MEMRI in CNS investigations and …

Analysis Of Coherence Between Electromyographic (Emg) Signals To Examine Neural Correlations In Muscular Activation During Standing Balance Tasks: A Pilot Study, Anuj Ojha

Culminating Experience Projects

The motor coordination of the muscles is controlled by the Central Nervous System (CNS), but the precise neural mechanisms for the CNS coordinating the muscles are not completely understood. The purpose of my study was to find the EMG-EMG coherence in different neural frequency bands to examine the neural correlations during muscle activation. EMG signal was recorded from six different healthy young subjects. The EMG signal with sampling frequency fs=1200 Hz was collected for 30 seconds (t=30 sec) from three different muscles on both legs: - tibialis anterior, medial gastrocnemius and soleus. The data were collected for the following four …

Acromial Insufficiency Fractures In Reverse Total Shoulder Arthroplasty: A Biomechanical Study, Alicia Kerrigan

Electronic Thesis and Dissertation Repository

Reverse total shoulder arthroplasty (RTSA) is increasingly utilized in the aging population, with a growing list of surgical indications including rotator cuff tear arthropathy, proximal humerus fractures, and revision arthroplasty. Acromial insufficiency fractures following RTSA are poorly understood, difficult to diagnose, and associated with inferior clinical outcomes. There is limited knowledge in the literature regarding the etiology of post-operative acromial fractures. The purpose of this study is to evaluate the role of implant parameters on acromial strain following RTSA.

Using a cadaveric model, a custom designed modular RTSA system was implanted that allowed for evaluation of modifiable parameters including glenoid …

Assessing Biofiltration Without Ozonation For Removal Of Trihalomethane Precursors In Drinking Water At The Beaver Water District Drinking Water Treatment Plant, Sana Ajaz

Graduate Theses and Dissertations

Biofiltration without pre-ozonation has the capability to remove natural organic matter (NOM) fractions that serve as precursors of disinfection byproducts (DBPs), which include the four regulated trihalomethanes (THMs) and dichloroacetonitrile (DCAN). Rapid small-scale column tests (RSSCTs) and Pilot Plant filters operated at empty-bed contact times (EBCTs) of 4, 8, and 16 minutes were used to evaluate the performance of nutrient-amended (free ammonia and phosphorus) biofiltration for THM and DCAN precursor removal, as measured using formation potential (FP) tests. NOM surrogates – which include dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA254) and fluorescence-PARAFAC components – were measured weekly throughout the …

Wireless Ekg, James Kerman, Chin Chao, Galen Wu, Eric Burstedt

Mechanical Engineering

In 2016, Dr. Ahmad Nooristani identified a need for a personal EKG that is cheaper and simpler than hospital grade systems, but more accurate than personal devices currently on the market. Two previous teams did significant background research, prototyping, focusing on ease of use, portability, and physical specifications. However, neither team was able to produce a device with electrodes that could successfully collect an EKG signal and transmit it to a phone or tablet, one of the main requirements from the Dr. Nooristani. This team focused on designing a six lead, five electrode EKG device to transmit EKG data from …

Il-12 Gene Electrotransfer Triggers A Change In Immune Response Within Mouse Tumors, Guilan Shi, Chelsea Edelblute, Sezgi Arpag, Cathryn Lundberg, Richard Heller

Bioelectrics Publications

Metastatic melanoma is an aggressive skin cancer with a relatively low survival rate. Immune-based therapies have shown promise in the treatment of melanoma, but overall complete response rates are still low. Previous studies have demonstrated the potential of plasmid IL-12 (pIL-12) delivered by gene electrotransfer (GET) to be an effective immunotherapy for melanoma. However, events occurring in the tumor microenvironment following delivery have not been delineated. Therefore, utilizing a B16F10 mouse melanoma model, we evaluated changes in the tumor microenvironment following delivery of pIL-12 using different GET parameters or injection of plasmid alone. The results revealed a unique immune cell …

Modeling And Simulation Methodologies For Spinal Cord Stimulation., Saliya Kumara Kirigeeganage

Electronic Theses and Dissertations

The use of neural prostheses to improve health of paraplegics has been a prime interest of neuroscientists over the last few decades. Scientists have performed experiments with spinal cord stimulation (SCS) to enable voluntary motor function of paralyzed patients. However, the experimentation on the human spinal cord is not a trivial task. Therefore, modeling and simulation techniques play a significant role in understanding the underlying concepts and mechanics of the spinal cord stimulation. In this work, simulation and modeling techniques related to spinal cord stimulation were investigated. The initial work was intended to visualize the electric field distribution patterns in …

Superelastic And Ph-Responsive Degradable Dendrimer Cryogels Prepared By Cryo-Aza-Michael Addition Reaction, Juan Wang, Hu Yang

Chemical and Biochemical Engineering Faculty Research & Creative Works

Dendrimers exhibit super atomistic features by virtue of their well-defined discrete quantized nanoscale structures. Here, we show that hyperbranched amine-terminated polyamidoamine (PAMAM) dendrimer G4.0 reacts with linear polyethylene glycol (PEG) diacrylate (575 g/mol) via the aza-Michael addition reaction at a subzero temperature (-20 °C), namely cryo-aza-Michael addition, to form a macroporous superelastic network, i.e., dendrimer cryogel. Dendrimer cryogels exhibit biologically relevant Young's modulus, high compression elasticity and super resilience at ambient temperature. Furthermore, the dendrimer cryogels exhibit excellent rebound performance and do not show significant stress relaxation under cyclic deformation over a wide temperature range (-80 to 100 °C). The …

Chemically Active Rheological Modifiers For The Improved Clinical Use Of Cyanoacrylates, Kyle Joseph Garcia

All Dissertations

Over 100 million surgical incisions, 50 million traumatic wounds, and 20 million minor lacerations from cuts and grazes are treated globally each year. One study determined that globally internal and external wounds occur for 40% and 37% of cases respectively for a total of 111 million patients that were treated for wounds. The remaining 23% of patients were treated for minor lacerations and trauma in the emergency room. These wounds require immediate medical attention including pressure application, sutures, clips, tissue cautery, and/or topical hemostatic agents to cease hemorrhage or the exit of other bodily fluids. With blood flow ceased, wound …

Finite Element Analysis Of Humerus With Impact At Distal End And The Mechanical Effect Of Bone Rehydration, Amy Gutierrez

Theses and Dissertations

Numerical modeling accuracy is dependent upon correct material property determination and input. This thesis demonstrates the importance in both numerical modeling and material characterization, two aspects of biomedical research that are intimately linked. The first study investigates the shear forces experienced on the humerus from a humeral impact on the distal end using 3D CAD model of a humerus and ANSYS for a finite element analysis. The humeral bone was analyzed with an impact on the distal end to signify falling on the elbow. A humeral model and a humeral model with a plate were both statically and dynamically simulated …

Numerical Simulation And Optimization Of Blalock-Taussig Shunt, Thomas Hess, Ramesh K. Agarwal

McKelvey School of Engineering Theses & Dissertations

The goal of this study is to create an optimized Blalock-Taussig shunt used to temporarily repair pulmonary vascular blockages allowing a child time to grow so a more permanent surgical repair of the heart and vasculature can be performed. Blalock-Taussig or BT shunts are a surgical procedure performed on infants suffering from cyanosis or “Blue Baby Syndrome.” A BT shunt is an artificial vessel placed between the right ventricle and the pulmonary artery to increase blood flow in the lung and blood oxygen saturation levels. In a study of 96 patients with currently in use modified BT shunts, 32 patients …

Automated Quantification And Evaluation Of Motion Artifact On Coronary Ct Angiography Images, Hongfeng Ma, Eric Gros, Scott G. Baginski, Zachary R. Laste, Naveen M. Kulkarni, Darin Okerlund, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Abstract

Purpose

This study developed and validated a Motion Artifact Quantification algorithm to automatically quantify the severity of motion artifacts on coronary computed tomography angiography (CCTA) images. The algorithm was then used to develop a Motion IQ Decision method to automatically identify whether a CCTA dataset is of sufficient diagnostic image quality or requires further correction.

Method

The developed Motion Artifact Quantification algorithm includes steps to identify the right coronary artery (RCA) regions of interest (ROIs), segment vessel and shading artifacts, and to calculate the motion artifact score (MAS) metric. The segmentation algorithms were verified against ground‐truth manual segmentations. The …

Impedance Sensing Of Cancer Cells Directly On Sensory Bioscaffolds Of Bioceramics Nanofibers, Hanan Alismail

Graduate Theses and Dissertations

Cancer cell research has been growing for decades. In the field of cancer pathology, there is an increasing and long-unmet need to develop a new technology for low-cost, rapid, sensitive, selective, label-free (i.e. direct), simple and reliable screening, diagnosis, and monitoring of live cancer and normal cells in same shape and size from the same anatomic region. For the first time on using an impedance signal, the breast cancer and normal cells have been thus screened, diagnosed and monitored on a smart bioscaffold of entangled nanowires of bioceramics titanate grown directly on the surface of implantable Ti-metal and characterized by …

Hip And Knee Biomechanics For Transtibial Amputees In Gait, Cycling, And Elliptical Training, Greg Orekhov

Master's Theses

Transtibial amputees are at increased risk of contralateral hip and knee joint osteoarthritis, likely due to abnormal biomechanics. Biomechanical challenges exist for transtibial amputees in gait and cycling; particularly, asymmetry in ground/pedal reaction forces and joint kinetics is well documented and state-of-the-art passive and powered prostheses do not fully restore natural biomechanics. Elliptical training has not been studied as a potential exercise for rehabilitation, nor have any studies been published that compare joint kinematics and kinetics and ground/pedal reaction forces for the same group of transtibial amputees in gait, cycling, and elliptical training. The hypothesis was that hip and knee …

Acetylation Profiles Of Histone And Non-Histone Proteins In Breast Cancer, Alla Karpova

McKelvey School of Engineering Theses & Dissertations

This study evaluates the impact of protein acetylation on breast cancer gene expression and the regulation of metabolism. Acetylation is the second abundant post-translational modification after phosphorylation, regulating protein activity and function. The alterations in acetylation of both histone and non-histone proteins is known to be related to many human diseases, including cancer. Acetylation and deacetylation of histones is closely associated with the regulation of gene expression, while acetylation of non-histone proteins may have a broad effect on major cellular processes, such as proliferation, metabolism, cell cycle and apoptosis, imbalanced regulation of which is essential for cancer development. Therefore, it’s …

Analysis And Classification Of 3-D Printed Collagen-Bioglass Matrices For Cellular Growth Utilizing Artificial Neural Networks, Trevor Schmitt

Theses and Dissertations

Introduction: Recent advances have shown the influence of biomimetic design on modulation of the extracellular matrix (ECM) and the role stiffness of it plays in cellular behavior. 2-D models for cellular growth poorly recapitulate the natural environment of cells, whereas application of a 3-D ECM model allows for a more biomimetic design for modeling cellular behavior. Integration of 45S5 Bioglass provides and osteostimulatory mineral component to these 3-D models, allowing for better mimicry of orthopedic design, affecting the mechanical and physiochemical properties of the ECM and leading to an increase in osteogenic behavior. 3-D Bioprinting allows for custom fabrication of …

Production And Biocompatibility Of Spider Silk Proteins In Goat Milk, Richard E. Decker Jr

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Due to its strength, flexibility, and biocompatibility, spider silk is a highly appealing material for applications in the medical field. Unfortunately, natural spider silk is difficult to obtain in large quantities because spiders are territorial and cannibalistic, making them impractical to farm. Synthetic spider silk proteins produced by transgenic hosts such as bacteria and goats have made it possible to obtain the quantities of spider silk needed to study it more fully and to investigate its potential uses. The spider silk proteins produced in our laboratory do not have an optimal purification method to remove all of the non-biocompatible contaminants …