Biomechanical Engineering Commons^™

Long-Term Simulation Of Stem Cell Mechanobiology, Manoochehr Rabiei

Mechanical and Aerospace Engineering Dissertations - Archive

An accurate representation of cellular mechanobiology necessitates the inclusion of subcellular elements characterized by minute masses and dimensions. These minute objects yield multiscale dynamic models with disproportionate terms, which require inordinate amounts of computational time to simulate. The computational requirements limit the time span of the simulation to time histories shorter than one second, even when employing supercomputers. This work presents a high-speed approach to simulating the mechanobiology of stem cells. The proposed approach separates the computational time from the size, and distribution, of masses of the subcellular elements, enabling the simulation of weeks-long cellular processes within hours on a …

Insights Into The Characterization And Degradation Of Electrospun Polycaprolactone Scaffolds For Tissue Engineering Applications, Caleb B. Wells

Theses and Dissertations

Electrospun polymeric biodegradable scaffolds are essential in tissue engineering, particularly for Engineered Tissue Vascular Grafts (ETVGs), which promise advancements in treating coronary artery disease, peripheral arterial disease, congenital cardiovascular defects, and renal disease. These scaffolds present a solution to issues with autologous graft availability and durability. While large-diameter grafts in low-pressure environments have seen success, small-diameter grafts in high-flow scenarios remain challenging. Understanding polymeric scaffold degradation and behavior during incubation, especially under dynamic mechanical loading, is vital for clinical translation of small-caliber ETVGs.

This research focuses on characterizing the mechanical and microstructural properties of electrospun polycaprolactone (PCL) scaffolds and their …

Simultaneous Evaluation Of Tibiofemoral And Patellofemoral Mechanics In Total Knee Arthroplasty: A Combined Experimental And Computational Approach, Yashar A. Behnam, Ahilan Anantha Krishnan, Hayden Wilson, Chadd W. Clary

Center for Orthopaedic Biomechanics: Faculty Scholarship

Contemporary total knee arthroplasty (TKA) has not fully restored natural patellofemoral (P-F) mechanics across the patient population. Previous experimental simulations have been limited in their ability to create dynamic, unconstrained, muscle-driven P-F articulation while simultaneously controlling tibiofemoral (T-F) contact mechanics. The purpose of this study was to develop a novel experimental simulation and validate a corresponding finite element model to evaluate T-F and P-F mechanics. A commercially available wear simulator was retrofitted with custom fixturing to evaluate whole-knee TKA mechanics with varying patella heights during a simulated deep knee bend. A corresponding dynamic finite element model was developed to validate …

Borophene And Graphene For Non-Enzymatic Biosensor- Ab-Initio Study, Omar A. Ismail

Theses and Dissertations

Non-enzymatic glucose sensing holds promise to overcome limitations associated with glucose oxidase, such as oxygen dependence and short shelf life. This study explores the potential sensing capabilities of borophene and graphene through direct interaction with various compounds, including β-glucose, uric acid, ascorbic acid, fructose, and acetaminophen. Using Density Functional Theory (DFT), we calculated binding energies and the respective Density of States (DOS) for these adsorbates on both graphene and borophene surfaces. Preliminary results suggest that borophene might exhibit nearly twice the affinity for β-glucose compared to graphene. Moreover, the calculated Density of States reveals distinct distortions in the electronic states …

Air-Jet Bioprinting Of Stem Cell-Encapsulated Alginate Micro-Droplets For Organoid Biomanufacturing, Mirabella B. Stump

Electronic Theses and Dissertations

Biomanufactured 3D-organoids show promise for modeling and treating various conditions, particularly insulin-dependent diabetes mellitus (type-1 diabetes). Pancreatic islet organoids serve as sustainable sources of insulin-producing β-cells, potentially restoring insulin regulation in patients and providing a long-term solution for diabetes. Hydrogel droplet printing is an emerging technique in regenerative medicine due to its advantageous tunability and biocompatibility; however, challenges of consistency, quality control, and scalability persist. To address these issues, we developed a novel air-jetting based droplet bioprinting system for the generation of monodispersed alginate micro-droplets. The objective of this project was to incorporate human induced pluripotent stem cells (hiPSCs) into …

Computational Modeling Using A Novel Continuum Approach Coupled With Pathway-Informed Neural Networks To Optimize Dynein-Mediated Centrosome Positioning In Polarized Cells, Arkaprovo Ghosal, Padmanabhan Seshaiyar Dr., Adriana Dawes Dr., General Genomics Inc.

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Kinematic Analysis Of Gait And Deep Knee Flexion For Pre- And Post-Operative Total Knee Arthroplasty, Samantha Collins

Electronic Theses and Dissertations

Osteoarthritis (OA) is a form of arthritis that develops in the joint due to overuse and aging causing pain, discomfort, and disability. Total Knee Arthroplasty (TKA) is a surgical procedure performed when OA symptoms are severe with an estimated 600,000 patients in the United States currently receiving TKA. Studies have reported dissatisfaction of the knee for 14-39% of patients. This study collected knee kinematics before and after surgery using stereo radiography for precise measurement of gait and deep knee flexion activities. Results showed healthy knee kinematics were not restored and no significant changes could be seen from OA kinematics in …

Exploration Of Motion Capture System To Investigate Human Shoulder Kinematics, Ola Alsaadi

Electronic Theses and Dissertations

The glenohumeral joint (GH) is commonly conceptualized as a ball-and-socket joint [1], and its center of rotation (COR) is presumed to coincide with the geometric center of the medial-superior region of the humeral head [2]. Recent research has endorsed improvements in COR estimation through invasive and noninvasive techniques, including cadaver studies, stereophotogrammetry, and motion capture (MOCAP) systems. Despite increased interest in wearable technology within human movement analysis, the problem of COR estimation employing MOCAP systems and its validation against bi-planar fluoroscopy remains relatively unexplored.

This study employed a marker-based MOCAP system to compare the accuracy, error, and precision of three …

Computational Methodology For Generating Patient-Specific Soft Tissue Representations, Ahilan Anantha Krishnan

Electronic Theses and Dissertations

This dissertation focused on modeling specimen-specific soft tissue structures in the context of joint replacement surgery. The research addressed four key aspects. The first study involved developing a workflow for creating finite element models of the hip capsule to replicate its torque-rotational response. Experimental data from ten cadaveric hips were used to calibrate the models, resulting in improved accuracy and relevance for surgical planning and implant design. The second study tackled the challenge of expediting the calibration of mechanical properties of the hip capsule to match patient-specific laxities. A statistical shape function model was proposed to generate patient-specific finite element …

Digital Twins Of The Living Knee: From Measurements To Model, Thor Erik Andreassen

Electronic Theses and Dissertations

Modern medicine has dramatically improved the lives of many. In orthopaedics, robotic surgery has given clinicians superior accuracy when performing interventions over conventional methods. Nevertheless, while these and many other methods are available to ensure treatments are performed successfully, far fewer methods exist to predict the proper treatment option for a given person. Clinicians are forced to categorize individuals, choosing the best treatment on “average.” However, many individuals differ significantly from the “average” person, for which many of these treatments are designed. Going forward, a method of testing, evaluating, and predicting different treatment options' short- and long-term effects on an …

Enhancing Human Key Point Identification: A Comparative Study Of High-Resolution Vicon Dataset And Coco Dataset Using Bpnet, Bibash Lama

Masters Theses

Accurately identifying human key points is crucial for various applications, including activity recognition, pose estimation, and gait analysis. This study presents a high-resolution dataset created using the VICON motion capture system and three differently oriented 2D cameras, that can be used to train different neural networks for estimating the 2D key joint positions of the person from the 2D images or videos. The participants in the study included 25 healthy adults (17 males and 8 females) performing normal gait movements for about 2 to 3 seconds. The VICON system captured 3D ground truth data, while the three 2D cameras collected …

Hierarchical Based Classifcation Method Based On Fusion Ofgaussian Map Descriptors Foralzheimer Diagnosis Using T1‑Weighted Magnetic Resonance Imaging, Nourhan Zayed, Shereen E. Morsy, Inas A. Yassine

Mechanical Engineering

Alzheimer’s disease (AD) is considered one of the most spouting elderly diseases. In 2015, AD is reported the US’s sixth cause of death. Substantially, non-invasive imaging is widely employed to provide biomarkers supporting AD screening, diagnosis, and progression. In this study, Gaussian descriptors-based features are proposed to be efcient new biomarkers using Magnetic Resonance Imaging (MRI) T1-weighted images to diferentiate between Alzheimer’s disease (AD), Mild Cognitive Impairment (MCI), and Normal controls (NC). Several Gaussian map-based features are extracted such as Gaussian shape operator, Gaussian curvature, and mean curvature. The aforementioned features are then introduced to the Support Vector Machine (SVM). …

Multi-Objective Design Optimization Of Two Configurations Of Ventricular Shunts For Hydrocephalus, Will Kirkpatrick

Theses and Dissertations

Hydrocephalus is developed when the flow of cerebrospinal fluid is obstructed in the ventricles and a pressure build-up is generated within the brain. Ventricular shunts are used to remove excess fluid from the brain, but these shunts have a common problem of failure due to the shunt being obstructed by the build-up of astrocytes. To address this, two sets of 27 designs of ventricular shunts were identified and analyzed with parameters that could potentially reduce obstruction risks. The performance of these designs was examined using fluid simulations on these two sets of 27 designs. One set explored close-tipped shunt designs, …

Nanoscale Modeling Of Membrane Systems Under Mechanical Deformation In Traumatic Brain Injury Using Molecular Dynamics, Anh Thi Ngoc Vo

Theses and Dissertations

Neuronal membrane disruption and mechanoporation are nanoscale damage mechanisms that critically affect brain cell viability during traumatic brain injury (TBI). These nanoscale cellular impairments are elusive in experiments and necessitate in silico approaches such as molecular dynamics (MD) simulations. Implementing MD, this research aims to investigate the effects of different key factors related to membrane deformation and damage, including force field resolutions, lipid compositions, and loading conditions.

To examine the impact of force field resolution, MD deformation simulations were conducted on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) lipid bilayer membranes, using all-atom (AA), united-atom (UA), and coarse-grained Martini (CG-M) force fields. The mechanical responses …

Hemodynamic Assessment Of Y-Incision Aortic Root Enlargement Using Computational Simulations, Astitwa Ghimire

Electronic Theses and Dissertations

The Yang procedure is a new aortic root enlargement technique used to enlarge the aortic annulus by multiple valve sizes. The procedure prevents patient prosthesis mismatch and establishes a viable platform for future valve-in-valve implantation. This study used the Yang procedure to investigate the hemodynamics in the aortic root and bioprosthetic valve regions after aortic root enlargement. Results indicate the velocity magnitude at the sinus regions of a patient who underwent the Yang procedure was slower, indicating risks of flow stasis and thrombosis. Simulation results denote computational models can be created for optimization of surgical procedures.

A Virtual Method For Establishing Femoral Stem Position In Total Hip Arthroplasty, Samuel Mattei

Electronic Theses and Dissertations

Total hip arthroplasty (THA) is one of the most successful orthopedic surgeries performed, in which the hip joint is reconstructed to improve functionality and decrease pain in the joint. Despite the success of these procedures, femoral stem misalignment remains an area that influences THA success. The relationship between the femoral stem geometry and implanted femoral stem size and orientation is underreported due to limitations in the collection of radiographic data used for clinical pre-operative templating. Furthermore, the influence of anatomic measurements on the direction and size of the femoral stem are not considered due to imaging technique and difficulties associated …

Finite Element Modeling Of Patient-Specific Total Shoulder Arthroplasty, Ignacio Rivero Crespo

Electronic Theses and Dissertations

Total Shoulder Arthroplasty (TSA) is a surgical procedure designed to improve joint functionality by replacing the articulation between the humeral head and the glenoid fossa. Anatomic Total Shoulder Arthroplasty (aTSA) and Reverse Total Shoulder Arthroplasty (rTSA) are two types of replacement surgery to relieve pain and restore function of the shoulder. The overall goal of this study was to evaluate the effects of variation of certain patient and implant alignment parameters that may influence long-term outcomes of these surgical procedures, including kinematics, joint loads and contact mechanics. Computational models of six TSA subjects, three aTSA and three rTSA, were created …

Fully Coupled Fluid Structure Interaction Simulation Of Bioprosthetic Heart Valves: A Numerical And Experimental Analysis, Masod Sadipour

Electronic Theses and Dissertations

Aortic stenosis impacts approximately 7% of the global population. In the past decade, the role of computational modeling has been becoming considerably important in the design of BHVs. To obtain reliable solutions in computational modeling, it is essential to consider accurate properties of bioprosthetic heart valves (BHVs), such as density and mechanical properties. Previous computational studies assumed (bovine pericardium) BP used in BHVs density was comparable to water or blood. Yet, BP is subjected to multiple treatments like fixation and anti-calcification. In Chapter 2, I measured BP density and its effect on BHV leaflet stress and strain. In the second …

Bespoke Bicycle Enclosure, Thomas Link, Kyle Mcafee, Marc Monier, Hunter Walden

Mechanical Engineering

Brian Higgins is an American veteran with retinitis pigmentosa who relies on cycling for transportation. The motivation for this project is to design and manufacture a refined prototype bicycle attachment to support him while biking in the rain and cold. The attachment will serve to enclose him for optimal protection from inclement weather, while maintaining sufficient mobility for daily cycling. Mr. Higgins’ bicycle is equipped with an attached sensor system which assists his visual impairment by using an ultrasonic sensor. Therefore, the attachment cannot adversely affect the function of the sensor system. The project timeline is set at approximately 7 …

Biomechanical Knee Joint For Exoskeleton, Gabriel Ireton Ahern, Calloway Miller, Christianna Altamura, Eric Mailes

Mechanical Engineering

Our senior design project consisted of designing and manufacturing a biomechanically accurate, actuated knee joint to be integrated into an exoskeleton being developed by the Lower Limb Exoskeleton Assist Project (LLEAP), a part of the EMPOWER student association at Cal Poly, San Luis Obispo. As the human knee flexes and extends throughout gait motion, the center of rotation changes. Currently marketed exoskeletons have one point of rotation, which over constrains the knee and causes misalignment between the user and the suit [1]. Our goal was to mimic natural knee joint motion by changing the center or rotation, thus reducing misalignment …

Patient Movement Monitoring Based On Imu And Deep Learning, Mohsen Sharifi Renani

Electronic Theses and Dissertations

Osteoarthritis (OA) is the leading cause of disability among the aging population in the United States and is frequently treated by replacing deteriorated joints with metal and plastic components. Developing better quantitative measures of movement quality to track patients longitudinally in their own homes would enable personalized treatment plans and hasten the advancement of promising new interventions. Wearable sensors and machine learning used to quantify patient movement could revolutionize the diagnosis and treatment of movement disorders. The purpose of this dissertation was to overcome technical challenges associated with the use of wearable sensors, specifically Inertial Measurement Units (IMUs), as a …

A Proof Of Concept For Detection Of Palato-Lingual Contact Without Intraoral Electrodes In A Human Participant, Amitava Biswas

Master's Theses

The author of this thesis conceived and investigated an unexpected electrical signal that may not be noticed during regular electroglottography (EGG) when electrodes are conventionally placed on the anterior surface of the throat. It appears that there is a measurable electrical signal from the EGG equipment when electrodes are placed over the frontal cheek (belly of zygomatic muscle), and the tongue is elevated to contact the hard palate, or the tongue is lowered to break the contact. Therefore, this phenomenon is designated as unconventional electroglottography (UEGG, Dr. Steven Cloud, private communication, July 17, 2022).

Two distinctive patterns of waveforms were …

Blood Flow Regulates Atherosclerosis Progression And Regression, Morgan A. Schake

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Atherosclerosis is the most prevalent pathology of cardiovascular disease with no known cure. Despite the many systemic risk factors for atherosclerosis, plaques do not form randomly in the vasculature. Instead, they form around bifurcations and the inner curvature of highly curving arterial segments that contain so-called disturbed blood flow that is low in magnitude and multidirectional over the cardiac cycle. Conversely, straight, non-bifurcated arterial segments that contain moderate-to-high and unidirectional (i.e., normal) blood flow are protected from plaque development. Thus, blood flow is a key regulator of atherosclerosis that may be able to be leveraged to develop new therapeutics. Towards …

Concurrent Validity Study Of 3d Motion Measurement Systems: Vicon Vs. Xsens, Pias Das

Masters Theses

As the Inertial Measurement System (IMS) being a potential alternative to the Optoelectronic Measurement System (OMS) in terms of capturing comprehensive and objective musculoskeletal data, they need to be verified concurrently with the OMS before we start using the IMS in clinical motion analysis. To achieve this, a concurrent validity experiment of the Xsens system (IMS) in comparison to the Vicon system (OMS) was conducted for both upper and lower extremity movements during walk, squat, and lateral lunge (left and right) to quantify the degree of similarity of kinematic data between the two systems by direct comparison, root mean square …

Nanomaterials For Cardiovascular Engineering, Roya Bagheri

Dissertations, Master's Theses and Master's Reports

Cardiovascular diseases and disorders (i.e., those related to heart and blood vessels) are the main reasons for mortality worldwide. Nanomaterials, with their unique morphologies and properties, have a great potential for advancing cardiovascular engineering to treat diseases and disorders. In this dissertation, several cardiovascular applications of conductive nanomaterials were investigated. First, a conductive nanomaterial was explored to fabricate biohybrid nanomaterial-cardiomyocyte (CM – heart muscle cell) systems. Using Carbon Nanotube (CNT) forest as a 3D porous and conductive scaffold was investigated. The influence of the CNT forest on the viability, attachment, and spreading of CMs and their genetic information was …

Finite Element Analysis Of 3d-Printed Pcl Scaffolds, Ireolu K. Orenuga, Joao Soares, Phillip D. Glass, Daeha Joung Ph.D.

Undergraduate Research Posters

Finite Element Analysis of 3D-printed PCL Scaffolds for Synergizing Cellular Micro-Environment and Mechanical Stimuli to Enhance Engineered Tissue Growth in Vitro

Ireolu Orenuga,1 Phillip Glass,2 Daeha Joung,2 Joao S. Soares1

1. Department of Mechanical and Nuclear Engineering, College of Engineering, Virginia Commonwealth University
2. Department of Physics, College of Humanities & Sciences, Virginia Commonwealth University

Introduction: Tissue engineering aims to create viable and functional engineered tissues via biodegradable scaffolds and autologous cells. Scaffolds play an essential part in organizing the architecture of developing tissues and aid in the proper function of implants acutely by serving as mechanical support and long-term by …

Hypoxic Incubation Chamber, Simone Lisette Helfrich, Makenzie Nicole Jones

Master's Theses

This paper describes the design, manufacturing, and testing of a novel controllable hypoxic incubator with fully functional oxygen gas control and temperature control in a humid environment. On the current market, a majority of the few hypoxic incubators use pre-mixed gas that does not offer precise control over gas concentration. The objective for this project was to create a chamber that allows the user to set the O2 concentration to varying set points of % O2 while maintaining the chamber at a constant body temperature, CO2 level, humidity, and sterility. To start the project, multiple concepts were developed for the …

Computational Simulations Of The Effects Of Gravity On Lymphatic Transport, Huabing Li, Huajian Wei, Timothy P. Padera, James W. Baish, Lance L. Munn

Faculty Journal Articles

Physical forces, including mechanical stretch, fluid pressure, and shear forces alter lymphatic vessel contractions and lymph flow. Gravitational forces can affect these forces, resulting in altered lymphatic transport, but the mechanisms involved have not been studied in detail. Here, we combine a lattice Boltzmann-based fluid dynamics computational model with known lymphatic mechanobiological mechanisms to investigate the movement of fluid through a lymphatic vessel under the effects of gravity that may either oppose or assist flow. Regularly spaced, mechanical bi-leaflet valves in the vessel enforce net positive flow as the vessel walls contract autonomously in response to calcium and nitric oxide …

Development Of A Reverse Engineered, Parameterized, And Structurally Validated Computational Model To Identify Design Parameters That Influence American Football Faceguard Performance, William Ferriell

All Dissertations

Traumatic brain injury (TBI) continues to have the greatest incidence among athletes participating in American football. The headgear design research community has focused on developing accurate computational and experimental analysis techniques to better assess the ability of headgear technology to attenuate impacts and protect athletes from TBI. Despite efforts to innovate the headgear system, minimal progress has been made to innovate the faceguard. Although the faceguard is not the primary component of the headgear system that contributes to impact attenuation, faceguard performance metrics, such as weight, structural stiffness, and visual field occlusions, have been linked to athlete safety. To improve …

Developing New Crutch Tip Design For Overall Increased Stability And Improved Movement On Different Terrains, Lauren Skinner

Honors Theses

Crutches are a mobility assistive device that are often used in various situations, such as post- surgical rehabilitation and recovery after injury. The current crutch tip design that is used on today’s crutches are often unstable and do not provide quality movement on different terrains, such as snow, ice, mud, and wet surfaces. These problems would be solved with a new tip design that could be attached to existing crutches or manufactured with the crutch itself. The team’s solution to this problem is a crutch tip with modular parts. The tip would attach to the shaft of the crutch like …