Biomedical Engineering and Bioengineering Commons^™

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 …

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

Dissertations

No abstract provided.

Advanced Risk Models To Predict Surgical Site Infections Using Machine Learning Approaches And Risk-Adjusted Control Charts, Rabia Emhamed Al Mamlook

Dissertations

Even though most infections are treatable with antibiotics, Surgical Site Infections (SSIs) remain a significant healthcare problem as they increase hospital stays, require additional treatments, reduce a patient’s quality of life, and increase morbidity and mortality. To reduce the risks and to encourage the highest quality healthcare, it is important to measure, predict, and monitor the risk of SSIs. Preoperative prediction of SSIs is essential to facilitate the implementation of preventative strategies for high-risk patients. The overarching goal of this dissertation is to investigate new opportunities of using machine-learning (ML) to improve the accuracy and use of pre-operative prediction models …

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 …

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 …

Intelligent System For Laparoscopic Surgery Suturing Skill Assessment, Mohammed Yasser Al-Gailani

Dissertations

In laparoscopic surgery, which is also referred to as minimally invasive surgery (MIS), surgeons carry out surgical procedures with the assistance of a video camera and several surgical instruments. Laparoscopic surgeons should possess excellent eye-hand coordination capabilities, strong cognitive knowledge, case and problem management, and manual dexterity skills. Such skills can be acquired through simulation using a basic, low-fidelity setup, such as the surgical box-trainer. General surgeons must pass a set of tests on a Fundamentals of Laparoscopic Surgery (FLS) Trainer device.

One pivotal skill for a successful operation is developing a sense of the applied forces on the tissue …

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 …

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 …

Development Of Functional Materials And Devices On Flexible Platforms Using Additive Print Manufacturing Processes For Biomedical And Environmental Applications, Dinesh Maddipatla

Dissertations

In recent years, considerable research has been vested into the development of printed electronics (PE) to explore the best ways of fabricating electronic devices on flexible platforms using additive print manufacturing processes. PE produces flexible devices that are compatible with complex geometries, foldable applications and conformal to curved surfaces, with a promising potential for large‐area device fabrication at relatively lower manufacturing costs. This dissertation focuses majorly on the design and fabrication of novel flexible functional materials and devices for biomedical and environmental applications using additive printing processes.

Initially, a simple paper-based low cost and rapid prototypable platform with oxygen sensors …

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 …

A 3d Image-Guided System To Improve Myocardial Revascularization Decision-Making For Patients With Coronary Artery Disease, Haipeng Tang

Dissertations

OBJECTIVES. Coronary artery disease (CAD) is the most common type of heart disease and kills over 360,000 people a year in the United States. Myocardial revascularization (MR) is a standard interventional treatment for patients with stable CAD. Fluoroscopy angiography is real-time anatomical imaging and routinely used to guide MR by visually estimating the percent stenosis of coronary arteries. However, a lot of patients do not benefit from the anatomical information-guided MR without functional testing. Single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is a widely used functional testing for CAD evaluation but limits to the absence of anatomical information. …

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 …

Identification Of Neurobiological Mechanisms Associated With Attention Deficits In Adults Post Traumatic Brain Injury, Ziyan Wu

Dissertations

Traumatic Brain Injury (TBI) is one of the major public health concerns with approximately 70 million new cases occurring worldwide per year. It is often caused by a forceful bump, blow, or jolt to the head, resulting in brain tissue damage and normal brain functions disruption. All grades of TBI, ranging from mild to severe, can cause wide-ranging and long-term effects on affected individuals, resulting in physical impairments, and neurocognitive consequences that permanently affect their abilities to perform daily activities. Attention deficits are the most common persisting neurocognitive consequences following TBI, which significantly contribute to poor academic and social functioning, …

Neurobiological Markers For Remission And Persistence Of Childhood Attention-Deficit/Hyperactivity Disorder, Yuyang Luo

Dissertations

Attention-deficit/hyperactivity disorder (ADHD) is one of the most prevalent neurodevelopmental disorders in children. Symptoms of childhood ADHD persist into adulthood in around 65% of patients, which elevates the risk for a number of adverse outcomes, resulting in substantial individual and societal burden. A neurodevelopmental double dissociation model is proposed based on existing studies in which the early onset of childhood ADHD is suggested to associate with dysfunctional subcortical structures that remain static throughout the lifetime; while diminution of symptoms over development could link to optimal development of prefrontal cortex. Current existing studies only assess basic measures including regional brain activation …

Schwann Cells In Combination With Gag-Mimetic Scaffolds For Spinal Cord Repair, Sharareh Hashemi

Dissertations

Spinal cord injury (SCI) being a devastating neurological dysfunction can cause extensive irreversible neuronal loss and axonal damage. Fifty-four cases of spinal cord injury per million people occur annually in the United States. Due to the loss of glial cells and demyelination of axons, the neuronal function of surviving neurons is disrupted leading to permanent loss of sensory and motor functions. The glial scar formed by astrogliosis at the chronic stage protects undamaged tissues, but it is known to be a major barrier for axonal regeneration. The limited regeneration capacity of spinal cord makes it challenging to successfully treat the …

Effects Of A Primary Blast-Induced Traumatic Brain Injury On The Susceptibility To Behavioral And Neuronal Deficits On A Susequent Blunt Trauma, Aswati Aravind

Dissertations

Soldiers are often exposed to more than one traumatic brain injury (TBI) event over the course of their service. In recent years, more attention has been drawn to the increased risk of neurological deficits caused by the 'blast plus' polytrauma, which typically is a blast trauma combined with other forms of TBI. The objective of this dissertation is to investigate if exposure to a blast TBI predisposes the brain to increased neurological deficits when followed with a second blunt head trauma. The behavioral and neuronal deficits resulting from a blast plus injury involving a mild-moderate blast followed by a mild …

Electrical Characterization And Detection Of Blood Cells And Stones In Urine, Nida Nasir

Dissertations

Urine contains an immense amount of information related to its physical, chemical, and biological components; hence, it is a promising tool in detecting various diseases. Available methods for detecting hematuria (blood in the urine) are not accurate. Results are influenced by many factors, such as, health and vitals of the patients, settings of the equipment and laboratories, which leads to false positive or false negative outputs. This necessitates the development of new, accurate, and easy-access methods that save time and effort. This study demonstrates a label-free and accurate method for detecting the presence of red and white blood cells (RBCs …

Enhanced Label Free Normal And Cancer Cells Classification Using Combined Parametric Modeling And Optical Techniques, Ayshathul Fouzia Abdul Gani

Dissertations

The development of label-free methods for cell classifications has been driven by the importance of early detection and identification of cancer disease. The future point-of-care (POC) treatment methods require rapid and real-time cancer screening techniques. As the labelled methods of cell classification are time-consuming processes and require a large amount of sample preparation along with skilled persons, they do not appear to be suitable for POC treatment methods. This necessitates the importance of such development. The label-free methods incorporate the biophysical properties of cells instead of biomarkers. The optical properties of cells have been frequently utilized for cell classification. This …