Biomedical Engineering and Bioengineering Commons^™

Axicons For Improved Resolution And Depth Of Focus In Adaptive Optics Scanning Light Ophthalmoscopy, Ruth E. Woehlke, Robert F. Cooper

Biomedical Engineering Faculty Research and Publications

Adaptive optics scanning light ophthalmoscopes are instrumental for studying the eye, yet they use truncated Gaussian illumination and are limited by diffraction, restricting resolution and depth of focus (DOF). Non-diffractive Bessel beams have emerged as an alternative. Here, we use two axicons configured as: (1) an extended DOF beam for resolving multiple retinal layers; and (2) an annular beam for increasing lateral resolution. We compare both approaches to truncated Gaussian illumination using a variety of metrics. Using Configuration 1, we successfully observed multiple retinal layers simultaneously. Using Configuration 2, we observed enhanced lateral resolution but decreased signal-to-noise ratio.

Challenges And Artificial Intelligence Solutions For Clinically Optimal Hepatic Venous Vessel Segmentation, Håvard Bjørke Jenssen, Varatharajan Nainamalai, Egidijus Pelanis, Rahul P. Kumar, Andreas Abildgaard, Finn Kristian Kolrud, Bjørn Edwin, Jingfeng Jiang, Joseph Vettukattil, Ole Jakob Elle, Smund Avdem Fretland

Michigan Tech Publications

Background:: Liver vessel identification is crucial for clinical disease assessment and treatment planning, especially concerning local treatment of liver tumors. As artificial intelligence (AI) develops in radiology, opportunities arise to craft models adept at hepatic venous vessel segmentation, opening possibilities for creating patient-specific models of the liver anatomy quickly, despite the diverse features of CT images encountered in clinical settings. Objective: This research evaluates the performance of AI models combined with various pre-processing filters for liver vessel segmentation, emphasizing clinically relevant results. A novel evaluation method was introduced to offer more anatomically accurate assessments, moving beyond traditional metrics like the …

An Injectable, Dual-Curing Hydrogel For Controlled Bioactive Release In Regenerative Endodontics, Meisam Omidi, Daniela S. Masson-Meyers, Jeffrey M. Toth

Biomedical Engineering Faculty Research and Publications

Regenerative endodontics seeks to restore the vascularized pulp–dentin complex following conventional root canal therapy, yet reliable neovascularization within the constrained root canal remains a key challenge. This study investigates the development of an injectable, dual-curing hydrogel based on methacrylated decellularized amniotic membrane (dAM-MA) and compares its performance to a conventional gelatin methacryloyl (GelMA). The dAM-MA platform was designed for biphasic release, incorporating both free vascular endothelial growth factor (VEGF) for an initial burst and matrix-metalloproteinase-cleavable VEGF conjugates for sustained delivery. The dAM-MA hydrogel achieved shape-fidelity via thermal gelation at 37 °C and possessed tunable stiffness (0.5–7.8 kPa) after visible-light irradiation. …

Anisotropic Object-Based Shifts Of Attention Arise From Unequal Influences Of Visual Field Meridians On Neural Attention Gradients, David H. Hughes, Adam J. Barnas, Adam S. Greenberg

Biomedical Engineering Faculty Research and Publications

Object-based attention prioritizes the processing of information appearing within a selected object. We previously showed an object-based shift direction anisotropy (SDA) whereby horizontal shifts are more efficient than vertical shifts (Barnas AJ, Greenberg AS. Atten Percept Psychophys 78: 1985–1997, 2016; Barnas AJ, Greenberg AS. Vis Cogn 27: 768–791, 2019), an effect modulated by the visual field meridians (Barnas AJ, Greenberg AS. Q J Exp Psychol (Hove) 77: 2516–2532, 2024). Our present aim was to understand how the functional brain mechanisms of attention give rise to the SDA. We hypothesized that the SDA arises from attentional resources being partitioned differently by …

Crevice Corrosion Mechanisms Of Cocrmo Alloys In Orthopedic Implants: Retrieval Analysis, Nano-Tribocorrosion And Cellular Responses, Hwaran Lee

All Dissertations

Mechanically assisted corrosion and non-mechanically (chemically) driven corrosion in modular junctions of orthopedic implants using cobalt-chromium-molybdenum (CoCrMo) alloys remain clinical concerns and may contribute to implant failure. The underlying corrosion mechanisms are not yet fully understood, leaving a critical research gap. We hypothesized that corrosion in modular junctions may be driven by aggressive local environments, including fretting, metal ion release (cobalt ion, Co²⁺), low pH and reactive oxygen species (ROS). This dissertation aims to (1) analyze corrosion modes and potential causes in modular junctions; (2) identify chemically driven corrosion modes on CoCrMo alloys using simulated inflammatory modular taper …

Mechanoregulation Of Osteogenesis And Adipogenesis Of Human Mesenchymal Stem Cells, Justin Caron

Master's Theses

Bone-related diseases (e.g., osteoporosis) are primarily treated with pharmacologic therapies that often exhibit limited efficacy and substantial side effects. Currently, bone marrow derived mesenchymal stem cells (MSCs) have become one of most important cell options in bone regeneration due to readily available sources, strong proliferation abilities, weak immune rejection responses, and strong osteogenic differentiation potential. While identifying the most effective approach to enhance osteogenic differentiation of MSCs for bone regeneration is challenging, understanding the regulatory mechanisms is crucial for improving therapeutic efficacy. Recent research has focused on developing strategies to enhance osteogenesis, which involve biophysical and biochemical stimulation. Mechanical and …

Effect Of Moderate Decrease In Contractility On Epithelial Cell-Cell Contacts Under External Stretch, Saika Sharmin

Mechanical & Aerospace Engineering Theses & Dissertations

Epithelial tissues are characterized by extensive cell–cell contacts and often subject to stretch during normal function. Cell-cell contact adhesion strength maintains mechanical continuity from cell to cell. Mechanical forces exerted by cells via actomyosin contractility are known to strengthen cell-cell adhesions to a certain extent. While it is known that a large decrease in contractility causes cell-cell contact rupture due to weakened adhesions, it is unclear how a moderate reduction in contractility affects cell-cell junction stability. Here, we studied how a moderate inhibition of non-muscle myosin II (NMII) affects the integrity of epithelial cell-cell contacts, especially when subject to the …

Towards Improving Computational Modeling Of The Lumbar Spine - Impact Of Material Properties And Laminotomy On Spinal Biomechanics, Isaac K. Kumi

Mechanical & Aerospace Engineering Theses & Dissertations

Spinal ligaments play a crucial role in maintaining the mechanical stability of the lumbar spine. These dense, collagenous tissues not only resist excessive motion but also distribute loads between spinal components to protect neural structures. Traditionally, the mechanical response of ligaments has been modeled using linear elastic assumptions, which treat the tissue as having a constant stiffness regardless of loading history. While this simplifies analysis, it fails to capture the time-dependent behaviors, such as creep, stress relaxation, and hysteresis, that are characteristic of biological tissues.

Viscoelastic modeling may provide a more physiologically accurate representation by incorporating both elastic and viscous …

Advanced Analytical Biosensing For Cancer Detection And Neural Diagnostics Using Tapered Optical Fiber (Tof), Protonic, And High Throughput Microplate –Based Technologie, Bayan Hassan Alharbi

Chemistry & Biochemistry Theses & Dissertations

This dissertation investigates the development and application of advanced biosensing technologies to enhance early disease detection, neurological diagnostics, and bioactive compound evaluation. The research spans four key areas. First, it introduces tapered optical fiber (TOF)-based plasmonic biosensors for the non-invasive detection of prostate cancer, demonstrating high sensitivity and specificity compared to conventional diagnostic methods.

Second, it explores the use of fluorescent biosensors to test the Transmembrane Electrostatically Localized Proton (TELP) theory, shedding light on the role of localized protons in neuronal signaling and energy transfer. Third, the work presents a high-throughput, microplate-based biosensing platform for analyzing mitochondrial function under nanosecond …

Mathematical Modeling Of Effects Of Tumor Location On Lung Function., Lamargaret Temukisa Johnson

Master of Engineering Theses

Lung cancer has the highest rates of incidence and mortality of all cancers. Most lung cancer tumors are Non-Small Cell Lung Cancer (NSCLC). NSCLC patients with lesions in the upper lobes are found to have better prognosis compared to those with lesions in the middle and lower lobes. Previous studies have suggested various causes for this discrepancy at both the organ-scale and tissue-scale. To model NSCLC growth in different locations within the lung, an organ scale lung model and tissue scale tumor model were coupled through the tissue pressure, and oxygen and carbon dioxide partial pressures. The coupling was used …

Development Of A Wearable Biosensor For Cortisol Detection In Human Sweat Utilizing Pani/Peo Polymer Blend And Nitrogen-Doped Graphene Quantum Dots, Cesar Sanchez

Theses and Dissertations

Since the development of the first biosensor in 1962, the evolution of commercially available wearable biosensors has been driven by an increasing consumer interest in real-time health tracking. However, challenges related to sensor sensitivity and cost have hindered progress. Deploying a novel approach, the biosensor integrates a blend of Polyaniline (PANi) and Polyethylene Oxide (PEO) along with Nitrogen-doped Graphene Quantum Dots (N-GQDs) to enhance sensitivity and electroactivity, crucial for cortisol detection. To optimize performance, three distinct synthesis methods for N-GQDs; hydrothermal, microwave, and hot plate synthesis were compared employing a bottom-up approach utilizing citric acid (CA) as the primary reactant …

Computational And Experimental Analysis Of Knee Kinematics And Gait Variability: The Effects Of Load, Speed, And Fatigue On Human Motion, Alfirio Trejo Jr.

Theses and Dissertations

This thesis investigates the biomechanical behavior of the human knee under varying conditions of motion, load, and fatigue, with a focus on clinical angle analysis and gait stability. Four studies were conducted using motion capture data and a modified Grood and Suntay Joint Coordinate System (JCS) to evaluate knee joint kinematics—specifically flexion-extension, abduction-adduction, and internal-external rotation. The first study examined the effects of incremental weight loads during isolated knee extension exercises, revealing dose-dependent increases in abduction and internal rotation that may contribute to joint stress. The second study assessed the impact of walking speed and asymmetric loading on gait, showing …

Interdigitated Gear-Shaped Screen-Printed Electrode Using G-Pani Ink For Sensitive Electrochemical Detection Of Stress Related Hormones Dopamine And Cortisol, Pritu Parna Sarkar

Theses and Dissertations

This research introduces a novel interdigitated gear-shaped graphene-based electrochemical biosensor for the simultaneous detection of dopamine (DA) and cortisol. Modified with graphene–polyaniline (G–PANI) conductive ink, the sensor increased active surface area—94.52% and 57% higher than Metrohm DropSens 110 and circular printed sensors, respectively. Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) Spectroscopy and X-ray diffraction (XRD) were employed for physicochemical characterization. The sensor detects dopamine and cortisol over a linear range of 0.1–100 µM, with limits of detection of 0.043 µM (R² = 0.98) and 0.0577 µg/mL (R² = 0.976), respectively, in phosphate-buffered saline (PBS) using redox probe. Electrochemical performance …

Optimization And Utilization Of Microbial Electrolysis Cells In Waste To Product Applications, Hayden Harrison

All Graduate Theses and Dissertations, Fall 2023 to Present

As the world searches for cleaner and more sustainable energy solutions, turning waste into fuel is an increasingly attractive strategy. This research focuses on microbial electrolysis cells, a new technology that uses bacteria and a small amount of electricity to convert organic waste—like food scraps or wastewater—into useful gases such as hydrogen and methane. These gases can be used as energy sources to reduce dependency on more traditional fuels.

This thesis tackles two key challenges that limit the real-world use of microbial electrolysis systems. First, it introduces a simpler and more effective method to stop hydrogen losses in single-chamber cells. …

Population Analysis Of Cyanobacteria In Rotating Algal Biofilm Reactors, Eric H. Matthews

All Graduate Theses and Dissertations, Fall 2023 to Present

Algal biofilms have numerous applications in wastewater treatment and bioproduct production. The Sustainable Waste-to-Bioproducts Engineering Center at Utah State University is working to develop rotating algal biofilm reactors (RABRs) to remove excess nitrogen and phosphorus from wastewater effluent while producing biomass for downstream production.

Genetic analysis of algal biofilms on various RABRs was performed to gain improved understanding of the biofilm populations. This analysis focuses on a pilot-scale RABR and how it compares to several other RABRs. Additionally, old methods of genetic analysis filtered out important cyanobacterial populations. A new method was developed to identify the cyanobacteria within the biofilms. …

Impact Of Cysteine And Tyrosine Dipeptides On Cho Cell Performance In A Perfusion Mimic, Corrin L. Pruitt

All Theses

Perfusion cell cultures typically achieve higher cell densities and generate higher volumetric productivities than fed-batch cultures due to continuous nutrient supply and spent media removal. Despite these advantages, perfusion cell cultures remain underutilized for licensed product manufacturing, primarily due to the lack of small-scale perfusion models for high-throughput process development and the complexities involved in media formulation capable of supporting high cell densities during long-term continuous operation. To avoid nutrient limitation at high cell densities, current perfusion processes rely on using higher perfusion rates, which results in significant media wastage and downstream product dilution. Therefore, there has been an effort …

A Deep Learning Approach For Semantic Segmentation And Its Application On Ctc., Samir Farag Harb

Electronic Theses and Dissertations

This dissertation explores the modeling and analysis of medical images, focusing on the intricate task of colon segmentation and subsequent 3D reconstruction, which are critical steps in Computed Tomography Colonography (CTC) systems. The primary objective of this research is to develop precise segmentation approaches to enhance the accuracy of colon identification and reconstruction from abdominal CT scans. Three distinct segmentation approaches are proposed and evaluated: a Markov Random Field (MRF)-based approach, a convolutional neural network (CNN)-based deep learning (DL) approach, and a sequential episodic training with dual contrastive learning Approach (G-SET-DCL) that has a flavor of few-shot learning (FSL). To …

Aging Effect On Effective Connectivity Within The Prefrontal-Motor Network And Postural-Related Muscle Responses During Dual-Task Paradigms, Jiahao Pan

Boise State University Theses and Dissertations

Falls are a significant global public issue for older adults, leading to severe health and social impacts. To understand the underlying mechanism of increased fall risk with aging, loss of postural automaticity has been suggested as increased prefrontal cortex and motor cortices activation, as well as worse balance performance in response to the secondary cognitive task. However, the interaction within these cortical regions and its effects on postural-related muscle responses are poorly understood. This dissertation investigated age-related changes in effective connectivity within the prefrontal-motor network, postural related lower limb muscle response, and biomechanical characteristics in response to the secondary cognitive …

Predictors Of Permanent And Temporary Motor Deficits In Patients Undergoing Glioma Resection: A Systematic Review And Meta-Analysis, Brian J. Conway, Stephanie A. Armstrong, Nada Botros, Sergey Tarima, Max O. Krucoff

Biomedical Engineering Faculty Research and Publications

Objective

To identify predictors of permanent and temporary motor deficits in patients undergoing glioma resection.

Methods

A literature search accessed the databases Ovid Medline, Scopus, Web of Science, Cumulative Index to Nursing and Allied Health Literature/EBSCO, PsychInfo, Cochrane, and Wiley for studies reporting motor outcomes following surgical resection of glioma. Outcomes were stratified by patient/tumor characteristics, preoperative condition, and intraoperative factors for both permanent and temporary motor deficits. Generalized estimating equations were used to generate odds ratios.

Results

A total of 1332 titles and abstracts were reviewed resulting in the evaluation of 261 full-text articles. Data were extracted from 67 …

Improving Echocardiographic Aortic Aneurysm Assessment In Marfan Syndrome Patients, Joshua Paik, Shubh P. Mehta, Samskrithi Sivakumar, Felix Dinklage, Ahhyun Lee, Benjamin J. Landis, Craig J. Goergen

Discovery Undergraduate Interdisciplinary Research Internship

Marfan syndrome (MFS) is a genetic connective tissue disorder caused by a variant of the fibrillin-1 (FBN1) gene, leading to abnormalities in organs reliant on tissue elasticity. Proximal thoracic aortic aneurysms (TAAs) are a major clinical concern, particularly in pediatric MFS patients, due to their risk of dissection or rupture. Diagnosis and monitoring of TAAs often depend on manual measurements of aortic root diameters from the parasternal long axis views of transthoracic echocardiograms. However, this method is prone to interobserver variability (IOV), which impacts consistency in clinical assessment. To mitigate these limitations, we developed a graphical user interface (GUI) that …