Biomedical Engineering and Bioengineering Commons^™

Decoding Human Movement Through Experiments And Simulation, Vishnu Deep Chandran

Dissertations

The ability to walk or move independently plays a decisive role in one's quality of life. This human ability requires complex coordination with several systems, such as the nervous, muscular, skeletal, and sensory organs, to execute movement tasks. Hence, any disorder of these systems from injury, disease, or aging severely affects the ability to walk or move independently. Disabilities that impair movement severely affect the quality of life. Therefore, studying the changes affecting human movement is necessary to improve the lives of individuals with impaired movement. Since human movement is complex and many systems interact in non-intuitive ways, the overarching …

Improving The Performance And Evaluation Of Computer-Assisted Semen Analysis, Ji-Won Choi

Dissertations

Semen analysis is performed routinely in fertility clinics to analyze the quality of semen and sperm cells of male patients. The analysis is typically performed by trained technicians or by Computer-Assisted Semen Analysis (CASA) systems. Manual semen analysis performed by technicians is subjective, time-consuming, and laborious, and yet most fertility clinics perform semen analysis in this manner. CASA systems, which are designed to perform the same tasks automatically, have a considerable market share, yet many studies still express concerns about their accuracy and consistency. In this dissertation, the focus is on detection, tracking, and classification of sperm cells in semen …

Assessing Structural And Functional Brain Alterations And Work-Related Fatigue In Non-Hyposmic And Hyposmic Covid-19 Survivors, Rakibul Hafiz

Dissertations

In the year 2019, life began to change at the advent of a global pandemic caused by the novel coronavirus. Mask mandates and mass vaccinations have mitigated the effects significantly, yet cases keep rising with new variants, especially, in densely populated countries, like India. Recent neuroimaging evidence shows the virus can attack the central nervous system (CNS). However, exactly which brain regions undergo structural and functional changes remain largely unknown. Many patients experience 'loss of/reduced sense of smell' (i.e., hyposmic) and an alarming number of survivors develop persistent symptoms ('long-COVID') for several months after initial infection. Fatigue is the most …

Design Of Self-Assembled Peptides For Wound Healing, Ka-Kyung Kim

Dissertations

According to the CDC, 15% of diabetic patients develop diabetic foot ulcers (DFU) and approximately 170,000 patients undergo non-traumatic amputation annually. DFU is a major complication of diabetes caused by non-healing full-thickness wounds through the dermis. The current treatments include blood sugar control, frequent debridement, offloading, moist wound care, infection treatment, and amputation. To achieve wound closure of DFU, appropriate wound care and antibiotic therapy are essential. Topical regimens include hydrocolloids, alginates, foam, silver-impregnated dressings, and hydrogels. Wound healing is a complex and dynamic interplay between the immune system, keratinocytes, and dermal cells (in case of cutaneous wound). Angiogenesis has …

A Bioactive Composite Scaffold Containing Zinc For Bone Tissue Engineering, Jennifer W. Moy

Dissertations

Non-union bone fractures occur during 5-10% of all bone fractures where the fracture is incapable of healing despite current surgical interventions with the use of bone grafts and graft substitutes. As an alternative, studies utilize growth factors and other biomolecules to differentiate mesenchymal stem cells into osteoblasts to aid in bone formation in vitro and in vivo studies. Zinc has known insulin-mimetic properties and are incorporated into multiple tissue engineering approaches to aid in osteogenesis, bone formation, and vascularization. In this work, mesenchymal stem cells (MSCs) were evaluated for the effect of zinc on osteogenesis. The supplementation of zinc in …

The Interconnection Of The Vestibular And Oculomotor Systems Analyzed In Healthy Young Adults By Examining Postural Sway, Cassandra Martin

Theses

In order to study the human brain in a non-invasive way, the vestibular and oculomotor systems have been analyzed simultaneously. To achieve this, an eye movement and balance assessment was conducted for 29 (23 male; 21.6 ± 3.8 years) healthy participants with no history of concussions, brain injuries, vertigo, migraines, brain surgeries, eye surgeries, or amblyopia. The tasks consisted of eyes open, eyes closed, horizontal saccades, vertical saccades, vergence jumps, horizontal vestibulo-ocular reflex (VOR), and vertical VOR. Each task was completed in two stances: feet shoulder width apart and feet together. Distance, velocity, sway area, center of pressure (COP) frequency, …

Synthesis And Characterization Of Glycosaminoglycan Mimetic Variants For Cartilage Tissue Engineering Applications, Richard David Vincent Jr.

Dissertations

No abstract provided.

Gradient Free Sign Activation Zero One Loss Neural Networks For Adversarially Robust Classification, Yunzhe Xue

Dissertations

The zero-one loss function is less sensitive to outliers than convex surrogate losses such as hinge and cross-entropy. However, as a non-convex function, it has a large number of local minima, andits undifferentiable attribute makes it impossible to use backpropagation, a method widely used in training current state-of-the-art neural networks. When zero-one loss is applied to deep neural networks, the entire training process becomes challenging. On the other hand, a massive non-unique solution probably also brings different decision boundaries when optimizing zero-one loss, making it possible to fight against transferable adversarial examples, which is a common weakness in deep learning …

Towards Adversarial Robustness With 01 Lossmodels, And Novel Convolutional Neural Netsystems For Ultrasound Images, Meiyan Xie

Dissertations

This dissertation investigates adversarial robustness with 01 loss models and a novel convolutional neural net systems for vascular ultrasound images.

In the first part, the dissertation presents stochastic coordinate descent for 01 loss and its sensitivity to adversarial attacks. The study here suggests that 01 loss may be more resilient to adversarial attacks than the hinge loss and further work is required.

In the second part, this dissertation proposes sign activation network with a novel gradient-free stochastic coordinate descent algorithm and its ensembling model. The study here finds that the ensembling model gives a high minimum distortion (as measured by …

Towards Understanding The Role Of Central Processing In Release From Masking, Nima Alamatsaz

Dissertations

People with normal hearing have the ability to listen to a desired target sound while filtering out unwanted sounds in the background. However, most patients with hearing impairment struggle in noisy environments, a perceptual deficit which current hearing aids and cochlear implants cannot resolve. Even though peripheral dysfunction of the ears undoubtedly contribute to this deficit, surmounting evidence has implicated central processing in the inability to detect sounds in background noise. Therefore, it is essential to better understand the underlying neural mechanisms by which target sounds are dissociated from competing maskers. This research focuses on two phenomena that help suppress …

Temporal Evolution Of Structure And Function In The Periphery And Central Auditory Systems With Mild Blast Induced Tinnitus In Rat Animal Models, Ningning Shao

Dissertations

Exposure to blast causes debilitating trauma including tinnitus among soldiers and civilians (Cave et al., 2007; Remenschneider et al., 2014; Singh et al., 2016). Tinnitus is a constant ringing noise perception without external acoustic event; it affects sleep, concentration, behavior, leading to suicidal tendencies (Swan et al., 2017). Though blast induced tinnitus has been studied, structural and functional dysfunctions along auditory systems have not been systematically studied. It was hypothesized in this work that blast causes tinnitus even while the ears are mechanically protected, and the damage occurred in both central and peripheral auditory systems, which contributed to increased anxiety …

Drug Releasing Hydrogels For Opioid Use Disorder, Kaytlyn M. Crowe

Theses

Ease of access to prescription opioids and the strength of synthetic opioids have contributed to the rise in over use disorders, overdose, and death rates during the opioid epidemic. The current overdose standard of care, rescue NLX (NLX), is a competitive antagonist to the μ-opioid receptor but has a relatively short period of action compared to opioid agonists, especially synthetic agonists. Rises in the abuse of these synthetic and semi-synthetic agents in recent years have shown the weaknesses of rescue NLX, as it can leave overdose patients vulnerable to renarcotization and precipitated withdrawal. To prevent both from occurring, we developed …

Alcohol As A Catalyst For Hiv-Associated Neuroinflammation And Tbi-Induced Iron Toxicity, Agnieszka Agas

Dissertations

Alcohol has long been considered an exacerbator of diseases, disorders, and injuries as well as many of the accompanying symptoms. As an alternative approach, this dissertation explores alcohol as a catalyst for two different human disease conditions, human immunodeficiency virus (HIV)-associated neuroinflammation and traumatic brain injury (TBI)-induced iron toxicity. In HIV-1 infection, this dissertation presents a novel anti-viral drug, called Drug-S, for a possible inhibition and treatment of HIV-1 disease progression.

The first aim explores the influence of alcohol with HIV-associated neuroinflammation on macrophage migration across an in vitro model of the blood brain barrier. There is a gap in …

Development Of Deep Learning Neural Network For Ecological And Medical Images, Shaobo Liu

Dissertations

Deep learning in computer vision and image processing has attracted attentions from various fields including ecology and medical image. Ecologists are interested in finding an effective model structure to classify different species. Tradition deep learning model use a convolutional neural network, such as LeNet, AlexNet, VGG models, residual neural network, and inception models, are first used on classifying bee wing and butterfly datasets. However, insufficient data sample and unbalanced samples in each class have caused a poor accuracy. To make improvement the test accuracy, data augmentation and transfer learning are applied. Recently developed deep learning framework based on mathematical morphology …

Plant-Derived Extracellular Matrix Mimetic Scaffolds For Bone Repair Applications, Jessica Cardenas Turner

Dissertations

Autologous and allogeneic bone grafts are currently used to treat large bone defects or fractures that will not heal. However, for patients with osteoporosis or other conditions that impair the natural bone healing process, such as diabetes, smoking, bed rest, aging, autologous bone graft, which is the patient's own bone, is limited in quantity and its healing potential may be compromised. Allograft bone, or donated bone, lacks the necessary biological activity and has poor integration into defect. There is an urgent need for constructs/grafts capable of promoting bone cell function in fracture healing and large bone defects where the endogenous …

Using Fnirs As An Objective Measure Of Susceptibility To Informational Masking, Min Zhang

Dissertations

Resolving complicated auditory scenes is crucial for daily communication where background sound is often present. However, most hearing aid (HA) and cochlear implant (CI) users have difficulties understanding speech when competing sound sources are present, resulting in reduced job opportunities and increased risk for social isolation. Perceptual interference from background sound is called auditory masking. At least two distinct masking phenomena exist, called energetic and informational masking (EM and IM).

In the first masking phenomenon, EM, target and masker energies coincide at the same time and frequency. Computational and physiological models of cochlear auditory processing can reliably predict listeners' performances …

Real Time Analysis Of Eye Movements Using Computer Aided Software, Farhan Ahmad

Theses

Eye movement analysis is a slow and tasking job that require a trained vision analyst to sift through hundreds of eye movements. The difficulty of the task increases when a subject has undiagnosed eye related disorders. One such disorder is Convergence insufficiency (CI) which affects nearly 12 million people in the US. Convergence insufficiency occurs when the eyes are unable to coordinate simultaneous inward movement for near focal tracking. Individuals with CI are unable to coordinate eye movements this can result in many symptoms such as double vision, blurred vision, headaches, vision strain, and fatigue. A diagnosis for CI relies …

The Effects Of Design Parameters On The Neural Recordings With Micro-Ecog Arrays, Manan Amish Sethia

Theses

In the field of neural prosthetics, electro-cortico-graph (ECoG) arrays are commonly used to record neural activity of the brain cortex both in animal and human subjects. A finite element model (FEM) was developed to simulate the electric field generated by a single neuron in the rat brain cortex and a micro ECoG array (µECoG) placed on the pia surface for recording the neural signal. The neuron was simulated as a dipole current source with a magnitude of 1µA and placed at three different depths in the motor cortex corresponding to different layers under the µECoG array. The array design was …

Development Of Novel Inks And Approaches For Printing Tissues And Organs, Shen Ji

Dissertations

Tissue engineering is a multidisciplinary field that investigates and develops new methods to repair, regenerate and replace damaged tissues and organs, or to develop biomaterial platforms as in vitro models. Tissue engineering approaches require the fabrication of scaffolds using biomaterials or fabrication of living tissues using cells. As the demands of customized, implantable tissue/organs are increasing and becoming more urgent, conventional scaffold fabrication approaches are difficult to meet the requirements, especially for complex large-scale tissue fabrication. In this regard, three-dimensional (3D) printing attracted more interest over the past decades due to its unrivaled ability to fabricate highly customized tissues or …

Experiments And Modeling Of The Chemo-Mechanically Coupled Behavior Of Polymeric Gels, Nikola Bosnjak

Dissertations

Polymeric materials consist of mutually entangled or chemically crosslinked long njitmolecular chains which form a polymer network. Due to their molecular structure, the njitpolymeric materials are known to undergo large deformation in response to various njitenvironmental stimuli, such as temperature, chemical potential and light.

When a polymer network is exposed to a suitable chemical solvent, the solvent molecules are able to diffuse inside the network, causing it to undergo a large volumetric deformation, known as swelling. In addition to volumetric deformation, this process involves the chemical mixing of the polymer network and solvent molecules, and is typically environmentally responsive. A …

Blast Shock-Wave Characterization In Experimental Shock Tubes, Sudeepto Kahali

Dissertations

Blast-induced traumatic brain injuries have affected U.S. soldiers deployed for extended periods in the gulf and Afghanistan wars. To identify the biomechanical and biochemical mechanisms of injury, critical in the identification of diagnostic and therapeutic tools, compressed gas-driven shock tubes are used by investigators to study shockwave-animal specimen interactions and its biological consequences. However, shock tubes are designed and operated in a variety of geometry with a range of process parameters, and the quality of shock wave characteristics relevant to field conditions and therefore the study of blast-induced traumatic brain injuries suffered by soldiers is affected by those conditions. Lab-to-lab …

Cycloidal-Drive Joint Design For Wearable Exoskeletons, Abhi J. Rawal

Theses

This thesis's scope was to construct a highly back drivable and compact joint design that can be used for wearable exoskeletons specifically designed to assist with rehabilitation. A compact cycloidal gear transmission was designed to satisfy the compactness requirement while ensuring the minimum torque is required for backdriving the mechanism. The joint was designed based on the compact cycloidal drive specifications, and the backdrivability test was performed to measure the minimum torque required (1.20 Nm) to backdrive. The joint design incorporates various important features such as rotation lock feature to prevent hyperextension, a housing design that offers the benefit of …

Investigating The Combined Effects Of Whole Body Vibration And Vestibular Stimulation On Spasticity And Dystonia In Cerebral Palsy, Peter A. Michael

Dissertations

This study identifies and addresses three voids and potential shortcomings associated with the classification, assessment and management of Cerebral Palsy (CP). These concerns should not undermine the significant advancement that has been made in this specific branch of rehabilitation, but addressing them is necessary. Cerebral Palsy is a group of motor impairments due to hypoxic-ischemic brain damage around the time of birth and very commonly manifests as excessive muscle tone and poor motor control. There are classifications within CP including spasticity and dystonia.

First, a level of discrepancy is present in the classification of CP between the clinical and research …

Biomechanical Loading Changes Between Species In Mild Blast-Induced Traumatic Brain Injury, Jose Juan Rodriguez

Dissertations

Blast-induced traumatic brain injury (bTBI) has become one of the leading injury modalities in military personnel and is considered a signature injury in veterans returning from conflicts in the Middle East. One of the main concerns in studying bTBI is translating animal experiments to clinical applications that can service veterans. Significant advances have been made using animal models in relating external shock waves to emerging neuropathophysiological and behavioral outcomes. However, it is unknown if these results are applicable to humans; and if so, can an interspecies transfer function be developed based on size, shape, and material response. This work aims …

Moisture Permeable Barrier Membranes For Toxic Gases And Vapors, Yufeng Song

Dissertations

Defense against small molecule toxic gases is an important aspect of protection against chemical and biological threat as well as chemical releases from industrial accidents. Current protective respirators/garments cannot effectively block small molecule toxic gases and vapors and retain moisture transmission capability without a heavy burden.

Metal organic frameworks (MOFs) have been used as highly effective adsorbents and catalysts to remove ammonia, cyanogen chloride, and sulfur dioxide from air. A nanopacked bed of nanoparticles of MOF by synthesizing them in the pores of microporous membranes is developed in the study. The submicron scale size of membrane pores ensures a large …

Comparison Of Longitudinal Changes In Resting State Functional Magnetic Resonance Imaging Between Alzheimer’S And Healthy Controls, Berk Can Yilmaz

Theses

Resting State Functional Magnetic Resonance Imaging (rs-fMRI) is a technique that is widely used for analyzing brain function using different approaches and methods. This study involves rs-fMRI analysis of Blood Oxygenation Level Dependent (BOLD) signals acquired from Alzheimer’s disease (AD) Patients and Healthy Controls (HC). Each subject in the study had both functional and anatomical images with at least one rs-fMRI scan with their Anatomical (T1) scans. Previous rs-fMRI studies have demonstrated that AD shows differences in Amplitude of Low Frequency (<0.1 Hz) Fluctuations (ALFF), and Regional Homogeneity (ReHo) measures according to HCs.

The aim of the study is to investigate individual and group level differences using ReHo and mALFF related …

A Model For Thermal Diffusion And Local Tissue Damage From The Measurement Of Temperature In Electrosurgical Incision, Marek Vira

Theses

The extremely high temperatures applied over extremely short time intervals that are characteristic of electrosurgery result in a unique tissue damage pattern. Cesarean delivery and hysterectomy, the two most frequently performed procedures in obstetrics and gynecology (OB/GYN), commonly employ electrosurgical incision. While it is controversial, it has been suggested that tissue damage produced by electrosurgery could increase surgical site infection rates. While recommendations for the settings in the use of the electrosurgical unit do exist, there is no current technique for real time assessment of the viability of tissue around the site of the electrosurgical incision. Current methods for analyzing …

Modulation Of Cerebellar Purkinje Cell Activity With Low Intensity Electric And Ultrasound Stimulation, Ahmet S. Asan

Dissertations

Non-invasive brain stimulation (NIBS) techniques garner significant interest due to their potential to offer instantaneous and region-specific treatments to neurological disorders. The cerebellum is one of the target sites for NIBS methods due to its central role in motor and cognitive functions. Among several modulation techniques, transcranial electric stimulations (tEs), in particular, transcranial direct and alternating current stimulations (tDCs/tACs), and low intensity focused ultrasound stimulation (LIFUS) show encouraging outcomes in clinical applications. tDCs and tACs are favored due to their low cost and accessibility while LIFUS offers high spatial resolution and deeper penetration without affecting the surrounding structures. In order …

Mechanical Characterization Of Animal Derived Starting Materials For Tissue Engineering, Bin Zhang

Dissertations

Animal derived starting materials are well established in the production of Tissue Engineered Medical Devices. Porcine specifically can be found in products ranging in application from hernia repair to breast reconstruction. Although this material has been largely accepted in the Tissue Engineering industry, little is known of its material properties and mechanical characteristics. A review of the scientific literature describes limited mechanical measures only on uncontrolled research grade material. The objective of this work is to mechanically characterize porcine starting material used in the medical device industry. Porcine skin is provided by Midwest Research Swine, LLC (MRS) an established supplier …

Scanless Optical Coherence Tomography For High-Speed 3d Biomedical Microscopy, Yahui Wang

Dissertations

Optical coherence tomography (OCT) is a high-resolution cross-sectional imaging modality that has found applications in a wide range of biomedical fields, such as ophthalmology diagnosis, interventional cardiology, surgical guidance, and oncology. OCT can be used to image dynamic scenes, in quantitative blood flow sensing and visualization, dynamic optical coherence elastography, and large-scale neural recording. However, the spatiotemporal resolution of OCT for dynamic imaging is limited by the approach it takes to scan the three-dimensional (3-D) space. In a typical OCT system, the incident light is focused to a point at the sample. The OCT system uses mechanical scanners (galvanometers or …