Engineering Commons^™

Modeling Instrument Design Risks In Medical Device Reprocessing, Manuel Andres Gutierrez

All Dissertations

Medical device reprocessing is an essential practice in healthcare delivery. While FDA regulations require device manufacturers to develop and validate reprocessing procedures, the increasing complexity of medical device designs and their use environments can increase the risks of inadequate reprocessing and associated device malfunctions and potential patient injury. While some design features present known difficulties for reprocessing, critical information needed to define relative risks or feature-specific parameters that increase or decrease risks of inadequate reprocessing is lacking. There is an urgent need for tools to quantify and predict reprocessing risks associated with design features used in surgical instruments.

The broad …

Type Ii Innate Lymphoid Cell Plasticity Contributes To Impaired Reconstitution After Allogeneic Hematopoietic Stem Cell Transplantation, Sonia J. Laurie, Joseph P. Foster, Danny W. Bruce, Hemamalini Bommiasamy, Oleg V. Kolupaev, Mostafa Yazdimamaghani, Samantha G. Pattenden, Nelson J. Chao, Stefanie Sarantopoulos, Joel S. Parker, Ian J. Davis, Jonathan S. Serody

Chemical and Biochemical Engineering Faculty Research & Creative Works

Type II innate lymphoid cells (ILC2s) maintain homeostasis and barrier integrity in mucosal tissues. In both mice and humans, ILC2s poorly reconstitute after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Determining the mechanisms involved in their impaired reconstitution could improve transplant outcomes. By integrating single-cell chromatin and transcriptomic analyses of transplanted ILC2s, we identify a previously unreported population of converted ILC1-like cells in the mouse small intestine post-transplant. Exposure of ILC2s to proinflammatory cytokines resulted in a mixed ILC1-ILC2 phenotype but was able to convert only a small population of ILC2s to ILC1s, which were found post-transplant. Whereas ILC2s protected against …

Characterizing Locust Anemotaxis: The Impact Of Sensory Perturbations On Flight Behavior, Yi-Xiao Huang

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis investigates the effects of sensory perturbations on locust flight behavior, with the goal of better understanding how locusts integrate multiple sensory inputs to maintain flight control. Through a series of experiments, locusts were subjected to visual impairment, turbulent wind conditions, mechanical impairments of their wings and antennae, and pheromonal interference. These perturbations allowed for the exploration of the contributions each sensory pathway makes to flight stability and navigation in a controlled environment.

Results show that while visual impairment does not significantly impact average flight speed, it increases variability in flight stability, suggesting that visual cues are important for …

Feasibility Study On Microwave Glucose Level Monitoring, Ricardo Cepeda

Theses and Dissertations

Diabetes management heavily relies on regular blood glucose monitoring, which traditionally involves invasive techniques. In recent years, significant research has been directed towards developing non-invasive glucose monitoring methods, particularly using electromagnetic waves. This study explores the feasibility of detecting blood glucose levels non-invasively by measuring the resonant frequency shifts of an antenna, influenced by the dielectric properties of blood. Microwave measurement techniques have garnered attention due to their ability to safely penetrate human tissue and detect biochemical markers like glucose. While previous studies have established a link between glucose concentration and dielectric properties, many techniques suffer from poor sensitivity or …

Two-Photon Imaging For Characterizing Tumor Microenvironmental Changes In Non-Small Cell Lung Cancer Associated With Metastatic Recurrence, Paola Monterroso Diaz

Graduate Theses and Dissertations

Lung cancer remains the leading cause of cancer deaths, comprising nearly 25% of all cancer deaths (Sung et al., 2021a). The five-year survival rate of patients with non-small cell lung carcinoma (NSCLC) remains significantly low given that over half present with locally advanced or metastatic disease at time of diagnosis, and experience tumor recurrence following therapeutic intervention (Tamura et al., 2015; Uramoto & Tanaka, 2014). Current evaluation techniques to assess treatment response are lacking, given they are implemented several weeks after treatment completion and are solely based on anatomical changes in tumor size, forgoing other criteria such as functional or …

Assessing Reproducibility Challenges In Clinical Metabolics, Darcy Lin Cochran

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Current metabolomics research is expanding to be multiplatform and interdisciplinary. Metabolomic analysis has the potential to provide detailed insight into any biological system of interest to analyze the underlying molecular mechanisms of variables like environment, disease, and genetics. Human clinical metabolomics is a major research area that is often focused on finding biomarkers or panels of biomarkers for different diseases. However, results are difficult to compare across different laboratories since the field of metabolomics has yet to widely adopt best practices for sample preparation, data acquisition and data processing, results are difficult to compare across different laboratories.

This thesis focuses …

Study Of Temperature Effects Of Glucose And Microwave Dielectric Dispersion Model, Ethan Grant Boone

Theses and Dissertations

In this study, the temperature effect of dielectric properties in various aqueous solutions containing glucose are examined. A design for a new testing chamber is introduced to provide improved conditions for testing to ensure accurate and precise measurements. A N-SMA Adaptor is used when obtaining dielectric characteristics of glucose solutions ranging 100-300mg/dl. Dielectric parameters are obtained adopting a modified Debye dispersion model. MATLAB is used to confirm coaxial dimensions are suitable fabrication designs using fixed dielectric parameters of air and water. Simulations and design models were implemented utilizing ANSYS High Frequency Structure Simulator and 3-D Modeler software to develop the …

3d Bioprinted Coaxial Tubule Optimization For Human Aortic Endothelial Cell Growth, Ilse Gabriela Perez Garcia

Theses and Dissertations

This paper introduces a research study of printing parameter optimization of extruded, cell-laden, 3D bioprinted coaxial tubules, as well as cell interaction observations. Optimization of printing parameters seeks to reduce variability of the tubules’ inner and outer diameters. The tubules were manufactured from a 0.4% Collagen I - 1.6% NaC6H7O6 (Sodium Alginate) bioink, that reaches gelation through interaction with a 3.2% CaCl2 (Calcium Chloride) solution. The bioinks were extruded through a dual syringe pump mechanism connected to a coaxial nozzle, which is mounted on an adapted 3D FDM (Fused Deposition …

Physicochemical Property Effects On Immune Modulating Polymeric Nanoparticles: Potential Applications In Spinal Cord Injury, Daniel J. Kolpek, Jaechang Kim, Hisham Mohammed, John C. Gensel, Jonghyuck Park

Markey Cancer Center Faculty Publications

Nanoparticles (NPs) offer promising potential as therapeutic agents for inflammation-related diseases, owing to their capabilities in drug delivery and immune modulation. In preclinical studies focusing on spinal cord injury (SCI), polymeric NPs have demonstrated the ability to reprogram innate immune cells. This reprogramming results in redirecting immune cells away from the injury site, downregulating pro-inflammatory signaling, and promoting a regenerative environment post-injury. However, to fully understand the mechanisms driving these effects and maximize therapeutic efficacy, it is crucial to assess NP interactions with innate immune cells. This review examines how the physicochemical properties of polymeric NPs influence their modulation of …

The Effect Of Pressure Gradients On Perceived Discomfort, Zachary Bush

All Theses

Introduction:

A pressure gradient is where high and low pressure meet. It is responsible for displacement and irritation of the skin commonly caused by tight bandages, bracelets, or socks. The irritation is at the edge where the skin is displaced by the high and low pressure. An analysis of the effect pressure gradients have on discomfort would have significant medical relevance for any device, fixture, or clothing pressed against the skin at high pressure. This primarily includes prosthetic and orthotic devices.

The bottom surface of the heel provides a naturally circular, uniform pressure profile. This makes it the optimal testing …

Ai-Driven Approach For Diagnosis Of Renal Transplant Rejection Based On Biomarkers Identification And Integration., Israa Sharaby

Electronic Theses and Dissertations

They kidney is a vital organ for which humans are fortunate to find a spare through transplantation to sustain critical body functions, offering a hope to those struggling with renal failure. Kidney transplant procedure is the optimal treatment for people who suffer from end-stage renal failure. However, there are posed challenges due to the risk of immune rejection and the limited availability of donors. Early detection of renal rejection can provide timely intervention and accurate diagnosis that are critical to improve the transplant outcomes. This study explores the innovative approaches for addressing the current challenges through biomarkers identification, imaging techniques, …

Demonstrating Feasibility Of Ultrasound-Sensitive Microbubbles Delivery To Treat Disruptions In The Blood Brain Barrier Endothelium, Rubens Jourdain

Theses and Dissertations

Vascular cognitive impairment and dementia (VCID) is one of the main causes of dementia. VCID is caused by age and other genetic factors that lead to disruptions in the blood brain barrier (BBB) and allow blood components to enter the brain. The currently available treatments of VCID include opening the BBB with high-frequency-ultrasound to deliver drugs to the brain. However, this only treats the already developed disease. Consequently, we developed a new drug delivery system whose goal is to restore the brain capillary endothelial cells (BCEC) lining the blood vessel. The objective of this study was to demonstrate the feasibility …

Advancing Biofabrication Methodologies To Develop Biomimetic Tissue Scaffolds For Musculoskeletal Applications, Nashaita Yezdi Patrawalla

Theses and Dissertations

Musculoskeletal injuries impose a significant global burden, affecting millions and generating an economic toll exceeding $14 billion. Tissue engineering has gained traction as a promising strategy offering potential for functional restoration of damaged musculoskeletal tissues. This research aims to advance biofabrication techniques for generation of biomimetic tissue scaffolds, by optimizing scaffold design and modulating fabrication process parameters to generate scaffolds for musculoskeletal regeneration with application-specific tailored properties. In this realm, collagen-based biomaterials have been extensively investigated for tendon and ligamentous applications, and in combination with bioceramics incorporated into the collagen framework to produce composite scaffolds that better recapitulate the native …

Eigenbin Compression For Reducing Photon-Counting Ct Data Size, Taly Gilat Schmidt, Zhye Yin, Jingwu Yao, Jiahua Fan

Biomedical Engineering Faculty Research and Publications

Background

Photon-counting CT (PCCT) systems acquire multiple spectral measurements at high spatial resolution, providing numerous image quality benefits while also increasing the amount of data that must be transferred through the gantry slip ring.

Purpose

This study proposes a lossy method to compress photon-counting CT data using eigenvector analysis, with the goal of providing image quality sufficient for applications that require a rapid initial reconstruction, such as to confirm anatomical coverage, scan quality, and to support automated advanced applications. The eigenbin compression method was experimentally evaluated on a clinical silicon PCCT prototype system.

Methods

The proposed eigenbin method performs principal …

The Clot Thickens: Investigation Of The Mechanism Behind Hypercoagulation In Covid-19 Patients, Toni Warnick

All Dissertations

Since its emergence in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been associated with cardiovascular complications, which correlate with illness severity and increased mortality. It was initially thought that this hypercoagulable state was induced by endothelial dysfunction or cytokine storm because of SARS-CoV-2 infection. Although platelets have been reported to express the SARS-CoV-2 primary target receptor, angiotensin-converting enzyme 2 (ACE2), this remains controversial due to conflicting findings that suggest minimal to no ACE2 expression on platelets. This ambiguity has led to exploring alternative entry pathways, notably via the virus’s RGD (arginine-glycine-aspartic acid) sequence within its spike protein receptor-binding …

Optimization Of Polymeric Micelles As A Delivery System For Crispr/Cas9 Ribonucleoprotein, Lucian Williams

All Dissertations

Clustered regularly interspaced short palindromic repeats (CRISPR) is an adaptive immune system in bacteria that has been harnessed to perform precise genetic modifications in mammalian cells. Among CRISPR-associated (Cas) proteins, Cas9 has emerged as a transformative tool in gene editing due to its simplicity, high specificity, and versatility compared to the other Cas proteins and gene-editing technologies. Despite its potential to cure genetic disorders, the clinical application of Cas9 has been hindered by challenges such as immunogenicity, off-target effects, and low delivery efficiency. To address these issues, this dissertation explores using polymeric nanoparticle systems to encapsulate and protect Cas9 and …

Multifunctional Peptides To Improve Nucleic Acid Delivery For Ovarian Cancer Treatment, Kharimat Lora Alatise

All Dissertations

RNA interference (RNAi) therapies, such as small interfering RNA (siRNA), offer a high-precision approach to reducing the expression of disease-promoting genes with minimal off-target effects. For aggressive diseases like ovarian cancer, RNAi therapy can serve as a robust treatment modality if delivered successfully. Over 70% of ovarian cancer patients are diagnosed in stages three and four, where the disease becomes more difficult to treat. High relapse rates and drug resistance in these stages demonstrate the need for novel strategies to sensitize tumors to chemotherapy, making siRNA a promising avenue for targeting resistance-associated oncogenes.

However, the delivery of siRNA remains a …

Investigating The Role Of Cd44 In Her2+ Breast Cancer Cells During Cancer Cell Redirection, Holly Caroline Jordan Campbell

All Dissertations

Despite a rise in survival rates of breast cancer patients due to advances in modern medicine, breast cancer is the most common type of cancer in women and is the second leading cause of cancer death in the United States. Early detection and a more personalized treatment of breast cancer has slowly improved patient outcomes. Nevertheless, there are impediments to better patient outcomes due to the complexity of the disease physiology. Therefore, there is a demand for a comprehensive understanding of cancer development as well as a need to understand tumor progression for enhanced therapies for patients.

Previous in vivo …

Precision And Efficacy Of Rna-Guided Dna Integration In High-Expressing Muscle Loci, Made Harumi Padmaswari, Gabrielle Bulliard, Shilpi Agrawal, Mary S. Jia, Sabin Khadgi, Kevin A. Murach, Christopher E. Nelson

Biomedical Engineering Faculty Publications and Presentations

Gene replacement therapies primarily rely on adeno-associated virus (AAV) vectors for transgene expression. However, episomal expression can decline over time due to vector loss or epigenetic silencing. CRISPR-based integration methods offer promise for long-term transgene insertion. While the development of transgene integration methods has made substantial progress, identifying optimal insertion loci remains challenging. Skeletal muscle is a promising tissue for gene replacement owing to low invasiveness of intramuscular injections, relative proportion of body mass, the multinucleated nature of muscle, and the potential for reduced adverse effects. Leveraging endogenous promoters in skeletal muscle, we evaluated two highly expressing loci using homology-independent …

Alteration Of Peripheral Cytokines In Alzheimer’S Disease, Zhengshi Yang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alzheimer’s disease (AD) is a progressive neurodegenerative disease with the clinical symptoms of gradual cognitive decline and memory loss. Biologically, abnormal accumulation of Aβ (Aβ) plaque and tau tangles in the brain are the core pathological hallmarks in AD. Although inflammatory response is not specific to AD, emerging evidence suggests that the disrupted innate immune system within the central nervous system, particularly microglial activation, might act as the bridge linking Aβ aggregation to pathological phosphorylation and aggregation of tau. The inflammatory response was suggested to initially have a neuroprotective role of attempting to clear Aβ plaques, and then become neurotoxic …

Mechanically Cost-Effective Approach For Bipedal Walking In Robots Using Instantaneous Collision Angle, Smit R. Patel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Humans, as bipedal locomotors, are effective at reducing the mechanical cost of transport (CoTmech) by adopting movement strategies and gaits that minimize energy expenditure for a given distance. By using different gaits at different speeds, leveraging their long spring-like tendons and muscle elasticity which store and release energy during movement, humans reduce the mechanical effort required for locomotion. Current locomotion solutions offered in bipedal robots, based on legacy walking and running gait models, are not great at energy efficiency unless walking at very low speeds. Additionally, the control system of robots, designed to ensure stability and adaptability, requires substantial resources, …

Delineating Genetic Influences On Neurodegenerative Disorders And Infectious Diseases Through Advanced Computational Methods, Xiaowei Zhuang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Genetics plays a critical role in understanding the molecular mechanisms underlying neurodegenerative disorders and pathogen evolution in infectious diseases. For example, identifying genetic variants associated with a disease phenotype uncovers functional pathways that could lead to potential drug targets and therapeutic interventions. In addition, tracking the genetic evolution of pathogens enables early detection and warning of infectious disease outbreaks. In both applications, given the large amount of genetic data, advanced computational methods, including longitudinal and multivariate models, could significantly boost the statistical power and capture interrelationships among traits, environmental factors and genetic influences. This dissertation focuses on four applications of …

Engineered Microalgae Cultivations Systems: Conversion Of Wastewater Nutrients Into Biofuels And Bioplastics, Jacob Watkins

All Graduate Theses and Dissertations, Fall 2023 to Present

Dissolved Nitrogen and Phosphorus in wastewater can contribute to harmful algae blooms if released into the environment. One technology that can be used to recover dissolved nutrients from wastewater is the Rotating Algae Biofilm Reactor (RABR), which supports microalgae growth in an easily-harvested biofilm and produces nitrogenand phosphorus-rich biomass that can be used to produce slow-release fertilizers, biofuels, and compostable bioplastics. This thesis (1) examines the effects of several environmental factors on the biomass production rate and nutrient removal efficiency of RABRs treating municipal wastewater, (2) quantifies the composition and biofuel yields of microalgae biomass cultivated using a RABR at …

Analysis Of An Outdoor Pilot-Scale Rotating Algae Biofilm Reactor For Power Optimization, Ash-Enhanced Productivity, And Nutrient Uptake, Peter F. Jeppesen

All Graduate Theses and Dissertations, Fall 2023 to Present

Outdoor testing of a rotating algae biofilm reactor (RABR) was performed to see how well it could remove nutrients from water and produce algae. By adjusting the operation settings, we found the lowest power needed to remove nitrogen and phosphorus. The lowest power values needed were 1.36 kWh per kilogram of nitrogen and 20.1 kWh per kilogram of phosphorus. The algae production rate reached a maximum of 7.09 grams per square meter per day. Detailed analysis showed that the reactor worked like a continuous flow system, and the performance was influenced by factors including light and temperature. The results also …

Sdf-1Α Mediates Primary Tumor Escape In Glioblastoma Through Activation Of Mesenchymal Transitions, Charles T. Froman-Glover

The Cardinal Edge

Glioblastoma (GBM), a highly aggressive primary brain tumor originating in glial cells, poses a significant challenge due to its rapid growth and invasive nature within healthy brain tissue.

Current treatments involve surgical resection, chemotherapy, and radiation. These treatments alone are not enough to cure this disease, and a better understanding of the mechanics of the tumor's micro-environment is imperative to furthering the field of cancer research. This research focuses on understanding the tumor microenvironment's impact, specifically investigating the role of stromal cell-derived factor 1 (SDF-1) mechanics on GBM aggressiveness. SDF-1 is known to facilitate disease progression by facilitating chemotaxis toward …

The Impact Of Cumulative And Acute Loading On Achilles Tendon Health, Performance, And Reported Pain In Collegiate Gymnasts, Julio Serrano Samayoa

Electronic Theses and Dissertations

Gymnasts are at a high risk of Achilles tendon (AT) injuries due to intense loads during takeoffs and landings. To better understand better the relationship between impact loading and its effects on tendon adaptation and athletic performance, this study uses Inertial Measurement Units (IMUs) to track AT loading across a collegiate gymnastics season. This data were compared against physiological and athletic performance metrics, obtained through force plates and ultrasound imaging, to explore how mechanical load influences reported pain and athletic performance. Results varied, with cumulative impacts being correlated with improved jump height (Spearman 0.362, Pearson 0.348), while peak power and …

Applications Of Computer Vision In Biomechanics And Orthopaedics, William Stewart Burton Ii

Electronic Theses and Dissertations

Machine learning has emerged as a key technology for enabling advanced computer vision systems. These systems now permeate many industries, and have enhanced traditional processes through autonomous interpretation of visual data. In the field of orthopaedics, the increasing prevalence of imaging highlights a need for similar tools. In many cases, however, direct translation of available frameworks fails to resolve the complex problems currently facing this field. Stringent performance requirements, complex visual environments, data scarcity, and implications for patient safety represent domain-specific factors which pose unique challenges to proven techniques. Novel approaches are needed to realize the full benefits of visual …

Detection Of Methane Leaks By The Use Of Mid-Range Infrared Camera, Jared Rosario, Oscar Salcido

Undergraduate Research Symposium Posters

Timely detection of methane leaks from natural gas infrastructure, like pipelines and valves, is essential for mitigating environmental and safety risks. This research focuses on using mid-wave infrared (MwIR) cameras on unmanned aerial systems (UAS) to detect leaks. By leveraging machine learning, the study aims to develop an efficient, real-time methane inspection system that operates directly on embedded processors on UAS platforms.

This project employs the FLIR G300a OGI camera for remote gas inspection, utilizing video preprocessing and optical flow to mask gas plumes in footage. The YOLOv8 deep learning model is used to detect gas pixels and segment the …

Phagolysosomes Break Down The Membrane Of A Non-Apoptotic Corpse Independent Of Macroautophagy, Shruti Kolli, Cassidy J. Kline, Kimya M. Rad, Ann M. Wehman

Biological Sciences: Faculty Scholarship

Cell corpses must be cleared in an efficient manner to maintain tissue homeostasis and regulate immune responses. Ubiquitin-like Atg8/LC3 family proteins promote the degradation of membranes and internal cargo during both macroautophagy and corpse clearance, raising the question how macroautophagy contributes to corpse clearance. Studying the clearance of non-apoptotic dying polar bodies in Caenorhabditis elegans embryos, we show that the LC3 ortholog LGG-2 is enriched inside the polar body phagolysosome independent of autophagosome formation. We demonstrate that ATG-16.1 and ATG-16.2, which promote membrane association of lipidated Atg8/LC3 proteins, redundantly promote polar body membrane breakdown in phagolysosomes independent of their role …

Ptsd Increases Risk For Hypertension Development Through Pvn Activation And Vascular Dysfunction In Sprague Dawley Rats, Xinqian Chen, Xin Yan, Chunxiu Yu, Qing-Hui Chen, Lanrong Bi, Zhiying Shan

Michigan Tech Publications

This study investigates the impact of single prolonged stress (SPS), a model of post-traumatic stress disorder (PTSD), on cardiovascular responses, hypothalamic paraventricular nucleus (PVN) activity, and vascular function to elucidate the mechanisms linking traumatic stress to hypertension. Although SPS did not directly cause chronic hypertension in male Sprague Dawley (SD) rats, it induced acute but transient increases in blood pressure and heart rate and significantly altered the expression of hypertension-associated genes, such as vasopressin, angiotensin II type 1 receptor (AT1R), and FOSL1 in the PVN. Notably, mitochondrial reactive oxygen species (mtROS) were predominantly elevated in the pre-autonomic regions of the …