Biomedical Engineering and Bioengineering Commons^™

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.

Site-Specific Glyco-Engineering Of Recombinant Thrombomodulin, Joseph M. Keil

ETD Archive

Thrombomodulin (TM), a membrane glycoprotein predominately expressed on endothelium, plays essential roles in regulating local hemostatic balance. Particularly, TM modulates the activity of thrombin from a procoagulant to an anticoagulant protease. When bound to TM, thrombin activates plasma protein C, which selectively inactivates coagulation factors Va and VIIIa. At the same time, TM-bound thrombin is unable to cleave fibrinogen or to activate platelets diminishing its procoagulant activity. recombinant TM456 is a promising anticoagulant candidate, but it has a very short half-life. TM is a proteoglycan and its O-linked glycosaminoglycan (GAG), chondroitin sulfate (CS), on the D3 domain contributes to TM’s …

Quantification And Identification Of Neuro-Electrophysiological Markers And Brain Network For Biomedical Applications, Shu Kang

Bioengineering Dissertations - Archive

Electroencephalogram (EEG) can detect and monitor neuro-electrophysiological signals in the human brain, including assessing brain function in newborns at risk of neurological injury and healthy adults undergoing intervention with prefrontal transcranial photobiomodulation (tPBM). Moreover, EEG-based brain functional connectivity can be assessed in either resting-state or task-based measurements using graph-theoretical network modeling. However, the management of newborns with mild hypoxic ischemic encephalopathy (HIE) is controversial, and no study has investigated the EEG-based brain network and information flow resulting from HIE. Also, the underlying electrophysiological mechanism of tPBM is still unclear, and further research is needed to determine optimal parameters for tPBM …

Development And Application Of A Microfluidic Platform For Quantifying Intra-Tumoral Compressive Stress., Zachary P. Fowler

Electronic Theses and Dissertations

Cancer progression is linked to the emergence of aberrant mechanical signaling in the tumor microenvironment. Modulation of extrinsic signals, such as ECM stiffness and composition, have been thoroughly explored. However, the development of solid stresses within the tumor remains poorly understood. To address this, we have developed a microfluidic platform that generates deformable alginate microbeads that allow for the quantification of compressive stresses generated within a growing glioblastoma (GBM) tumorsphere. PDMS microfluidic devices were fabricated via SU-8 mold with channels ranging from 10µm-40µm in diameter. Fluorescently labeled sodium alginate underwent a cross-linking reaction within the device to generate monodisperse beads …

Investigation Of Possible Inflammatory Response After Ultrasound And Microbubble Procedure In The Spinal Cord., Jenna Wilkerson

Electronic Theses and Dissertations

The purpose of this experiment is to explore the inflammatory effects of focused ultrasound paired with intravenously delivered microbubbles when used in the lumbar spinal cord. There are currently very few pharmaceuticals that can successfully enter the blood spinal cord barrier (BSCB). This technique used at the lumbar enlargement might allow targeted treatment of pathologies involving the spinal cord.

To test the possible inflammatory response of this technique, an animal experiment was performed. 15 animals were given a T12 laminectomy and allowed to fully recover. Once recovered, all animals received FUS+MB at L2 and were euthanized in groups of five …

Computational Comparison Of Medializing Tibial Tubercle Osteotomy And Trochleoplasty In Patients With Trochlear Dysplasia, Clare K. Fitzpatrick, Robert N. Steensen, Oliver Alvarez, Amy E. Holcomb, Paul J. Rullkoetter

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Medial patellofemoral ligament reconstruction (MPFLR) has emerged as the procedure of choice for recurrent patellar dislocation. This addresses soft tissue injury but does not address underlying anatomic factors, including trochlear dysplasia, that are commonly present and increase risk of dislocation. Quantification of the stability offered by other surgical interventions, namely, medializing tibial tubercle osteotomy (mTTO) and trochleoplasty, with and without MPFLR, may provide insight for surgical choices in patients with trochlear dysplasia. We developed subject-specific finite element models based on magnetic resonance scans from a cohort of 20 patients with trochlear dysplasia and recurrent patellar dislocation. The objectives of this …

Prevention And Reversal Of Elastin-Associated And Phosphate-Dependent Arterial Calcification Using Targeted Nanotherapeutics In Pre-Clinical Models, Fatema Tuj Zohora

All Dissertations

Vascular calcification can be life-threatening, involving calcium phosphate crystal deposits in the blood vessels. The calcification in the intimal layer of the arterial wall is usually associated with atherosclerotic plaque build-up that, in the advanced stage, harbors ‘dispersed’ and ‘spotty’ deposits of calcium phosphate crystals in the necrotic core of the plaque. In contrast, medial arterial calcification (MAC) can form independently of atherosclerosis and appears as ‘Railroad-like’ calcific deposits along degraded elastin lamellae in the medial layer of arteries. The mechanisms of such elastin-associated medial arterial calcification and potential therapies are the key concerns of this dissertation. MAC is common …

A Novel Brain Computer Interface Design, Steven Vogan

Senior Honors Theses

A brain computer interface (BCI) is a system which connects neural signals to a computer system. They have been used for controlling systems including robotics, on-screen computer control such as mouse movement, typing, and synthesizing audio signals. Invasive, or implanted, systems are often long-term medical solutions, or used for research where very clear signal is required. Non-invasive systems usually rely on exterior signals gathered through a headset using one or more electrode sensors. These signals are composed of sums of neuron activation potentials from brain activity and can be used to determine particular aspects of brain function. All BCIs rely …

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 …

Photodynamic Therapy To Treat Triple Negative Breast Cancer In Vitro, Hunter S. Warren

All Theses

Triple negative breast cancer (TNBC) is the most resilient form of breast cancer, being one of the leading causes of death for women and making up 7% of all cancer deaths. Photodynamic therapy (PDT) offers a minimally invasive solution to TNBC as a passive-targeting treatment that reduces the need for other well established yet harsh treatments that can be taxing on the patient. PDT involves the use of a high-energy red light on the area of a tumor injected with photosensitizers (PS) that generate reactive oxygen species (ROS) in the tumor, triggering cell death. The PS tetra(hydroxyphenyl)chlorin (m-THPC) was used …

The Effects Of Compression Wrapping Techniques And Primary Wound Dressings On Leg Skin Interface Pressure, James Cox

All Theses

Peripheral edema affects approximately 20% of people in the US over the age of 50 and is frequently encountered among individuals with conditions such as heart disease, prolonged immobility, and venous insufficiency.¹ Compression is an established therapeutic tool utilized for the management of several chronic edema presentations including lymphedema and venous leg ulcers.^2,3 Therapeutic efficacy of compressive applications can be evaluated by defining interface pressure (IP) and IP distributions associated with specific textile combinations.² During compressive applications where an open wound is present, primary wound dressings should be used in combination with compressive wraps. Primary wound dressings …

Tandem Peptides Targeting Her2 For Delivery Of Cd44 Sirna Into Her2+ Breast Cancer Cells In Vitro, James Kalogeros

All Theses

More than 300,000 women will be diagnosed with breast cancer, and approximately 48,000 women will die this year due to the disease in the United States. HER2+ breast cancer accounts for 20-25% of invasive breast cancer, and it has a worse prognosis and higher early-stage mortality rate than other breast cancer subtypes. Common treatments for HER2+ breast cancer involve surgical removal of the breast or systemic therapy with chemotherapeutic drugs, both of which cause damage to healthy tissue. Due to the lack of a natural ligand for the HER2 receptor, there is a need for improved targeting strategies for the …

Assessment Of Knee Flexion In Young Children With Prosthetic Knee Components Using Dynamic Time Warping, Mark Daniel Geil, Zahra Safaeepour

Faculty Articles

Introduction: Analysis of human locomotion is challenged by limitations in traditional numerical and statistical methods as applied to continuous timeseries data. This challenge particularly affects understanding of how close limb prostheses are to mimicking anatomical motion. This study was the first to apply a technique called Dynamic Time Warping to measure the biomimesis of prosthetic knee motion in young children and addressed the following research questions: Is a combined dynamic time warping/root mean square analysis feasible for analyzing pediatric lower limb kinematics? When provided at an earlier age than traditional protocols dictate, can children with limb loss utilize an articulating …

Approximate Entropy And Velocity Of Center Of Pressure To Determine Postural Stability: A Pilot Study, Natalie Tipton, Gordon Alderink, Samhita Rhodes

Open Access Publishing Support Funded Articles

The body’s postural control system is responsible for responding to perturbations of balance and keeping the body upright. During quiet standing, the center of pressure oscillates about the center of mass, counteracting imbalances. These oscillations can be analyzed to determine the degree of stability, which could be helpful in quantifying the effects of brain injuries. In this research, the center of pressure was recorded for stances with feet together and feet tandem, with eyes opened and eyes closed, in neurotypical participants. These signals were analyzed using indices of approximate entropy and velocity to determine how sensitive the measures were in …

Injectable Immunomodulatory Strategies To Enhance Muscle Recovery Following Injury, Tai Huu Huynh

Graduate Theses and Dissertations

Although skeletal muscle displays an astonishing regenerative capacity, injuries or diseases that resulted in bedridden or chronic muscle wasting can overwhelm this intrinsic feature of skeletal muscle and lead to functional deficit (range of motion and/or strength) and overall reduction in quality of life. Microenvironmental cues within injured skeletal muscle dictate regenerative and repair process which are tightly coordinated interplay among resident cells, cells recruitment and immune response following an assault in the muscle extracellular matrix (ECM). The successful regeneration of functional tissues requires both appropriate modulation of the inflammatory response, and activation of a variety of cell populations. Biomaterials …

Visual Complexity Of The Time-Frequency Image Pinpoints The Epileptogenic Zone: An Unsupervised Deep-Learning Tool To Analyze Interictal Intracranial Eeg, Sarvagya Gupta

Graduate Masters Theses

Epilepsy, a prevalent neurological disorder characterized by recurrent seizures, continues to pose significant challenges in diagnosis and treatment, particularly among children. Despite substantial advancements in medical technology and treatment modalities, localization of the part of brain that causes seizures (Epileptogenic Zone) remains a difficult task. Intracranial EEG (iEEG) is often used to estimate the epileptogenic zone (EZ) in children with drugresistant epilepsy (DRE) and target it during surgery. Conventionally, iEEG signals are inspected in the time domain by human experts aiming to locate epileptiform activity.

Visual scrutiny of the iEEG time-frequency (TF) images can be an alternative way to review …

Surface-Functionalized Silica Nanocarriers For Mitigating Water Stress In Wheat And Benefiting The Root Microbiome, Anthony Cartwright

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Changes in climate and shifting patterns of drought threaten the growth of important cash crops like wheat. The element silicon serves as a plant nutrient and shows promise for strengthening wheat against drought while remaining safe to both the crop and the positive bacteria that grow on its roots. Silicon can be added to wheat in the form of silicon-dioxide nanoparticles featuring protective coatings made from plant-beneficial nutrients. These nanoparticles can be engineered with high surface area or porous structures allowing them to be loaded with additional nutrients that can be delivered to crops. In a laboratory setting, such nanoparticles …

Exploring Versatile Glycosyltransferases From Microorganisms For Natural Product Biosynthesis, Jie Ren

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This dissertation is mainly focused on exploring versatile glycosyltransferases from different microorganisms with the purpose of biosynthesizing bioactive natural product glycosides through microbial fermentation. This engineered biosynthesis approach is environmentally friendly, safe, and efficient compared with plant extraction, chemical synthesis, and enzymatic synthesis. Additionally, we applied these characterized glycosyltransferases as efficient biocatalytic tools to produce novel glycosides to expand the chemical repertoire of nature. These novel compounds showed improved water solubility and some of them exhibited enhanced stability and biological activity, which laid the foundation for the development of new therapeutic agents.

In my dissertation research, I have discovered two …

Ultrasensitive Tapered Optical Fiber Refractive Index Glucose Sensor, Erem Ujah

Biomedical Engineering Theses & Dissertations

Refractive index (RI) sensors are of great interest for label-free optical biosensing. A tapered optical fiber (TOF) RI sensor with micron-sized waist diameters can dramatically enhance sensor sensitivity by reducing the mode volume over a long distance. Here, a simple and fast method is used to fabricate extremely sensitive refractive index sensors based on localized surface plasmon resonance (LSPR). Two TOFs (l = 5 mm) with waist diameters of 5 µm and 12 µm demonstrated sensitivity enhancement at λ = 1559 nm for glucose sensing (5–45 wt%) at room temperature. The optical power transmission decreased with increasing glucose concentration due …

Development & Validation Of Needle-Based Metrics For Hemodialysis Cannulation Skill Assessment, Ziyang Zhang

All Dissertations

Dialysis is a vital medical treatment for patients with end-stage renal disease. An arteriovenous fistula, a surgically created connection between an artery and a vein, is the preferred vascular access for dialysis due to superior clinical outcomes. However, cannulation complications caused by needle-related errors are common and dangerous, necessitating the need for effective cannulation training. Despite cannulation being a challenging and complex clinical procedure, little is known about the quantitative aspects of needle insertion dynamics necessary for skilled cannulation. The aim of this study was to develop meaningful and instructive needle-based metrics for cannulation skill assessment and training.

Two iterations …