Biomedical Engineering and Bioengineering Commons^™

Improved Orthopaedic Repairs Through Mechanically Optimized, Adhesive Biomaterials, Stephen Wheeler Linderman

McKelvey School of Engineering Graduate Student Theses & Dissertations

Despite countless surgical advances over the last several decades refining surgical approaches, repair techniques, and tools to treat tendon and tendon-to-bone injuries, we are still left with repair solutions that rely on fairly crude underlying mechanical principles. Musculoskeletal soft tissues have evolved to transfer high loads by optimizing stress distribution profiles across the tissue at each length scale. However, instead of mimicking these natural load transfer mechanisms, conventional suture approaches are limited by high load transfer across only a small number of anchor points within tissue. This leads to stress concentrations at anchor points that often cause repair failure as …

Approaches To Understanding The Function Of Intrinsic Activity And Its Relationship To Task-Evoked Activity In The Human Brain, Dohyun Kim

McKelvey School of Engineering Graduate Student Theses & Dissertations

Traditionally neuroscience research has focused on characterizing the topography and patterns of brain activation evoked by specific cognitive or behavioral tasks to understand human brain functions. This activation-based paradigm treated underlying spontaneous brain activity, a.k.a. intrinsic activity, as noise hence irrelevant to cognitive or behavioral functions. This view, however, has been profoundly modified by the discovery that intrinsic activity is not random, but temporally correlated at rest in widely distributed spatiotemporal patterns, so called resting state networks (RSN). Studies of temporal correlation of spontaneous activity among brain regions, or functional connectivity (FC), have yielded important insights into the network organization …

Ultrasound-Guided Optical Techniques For Cancer Diagnosis: System And Algorithm Development, Atahar Kamal Mostafa

McKelvey School of Engineering Graduate Student Theses & Dissertations

Worldwide, breast cancer is the most common cancer among women. In the United States alone, the American cancer society has estimated there will be 271,270 new breast cancer cases in 2019, and 42,260 lives will be lost to the disease. Ultrasound (US), mammography, and magnetic resonance imaging (MRI) are regularly used for breast cancer diagnosis and therapy monitoring. However, they sometimes fail to diagnose breast cancer effectively. These shortcomings have motivated researchers to explore new modalities. One of these modalities, diffuse optical tomography (DOT), utilizes near-infrared (NIR) light to reveal the optical properties of tissue. NIR-based DOT images the contrast …

Elucidating The Roles Of Astrocyte-Derived Factors In Recovery And Regeneration Following Spinal Cord Injury, Russell E. Thompson

McKelvey School of Engineering Graduate Student Theses & Dissertations

Central nervous system (CNS) injury often causes some level of long-term functional deficit, due to the limited regenerative potential of the CNS, that results in a decreased quality of life for patients. CNS regeneration is inhibited partly by the development of a glial scar following insult that is inhibitory to axonal growth. The major cell population responsible for the formation this glial scar are astrocytes, which has led to the belief that astrocytes are primarily inhibitory following injury. Recent work has challenged this conclusion, finding that astrocyte reactivity is heterogeneous and that some astrocytes are pro-regenerative following injury. Astrocyte transplantation …

A High-Throughput Screening Platform For In Vitro Elastic Fiber Production And The Mass Transport Properties Of The Elastic Fiber Compromised Arterial Wall, Austin John Cocciolone

McKelvey School of Engineering Graduate Student Theses & Dissertations

Elastin comprises nearly 50% of the wall in large elastic arteries and has a broad variety of physiological roles. As a structural extracellular matrix protein, elastin is responsible for the reversible elasticity in large arties that dampens pulsatile flow and ultimately reduces the workload on the heart. Structural compromise to the elastic fiber network is apparent in the elastin genetic disorders, supravalvular aortic stenosis and autosomal dominant cutis laxa-1, and acquired elastin disorders including hypertension, atherosclerosis, artery calcification, aneurysms, diabetes, and obesity. All of these disorders lead to an increased incidence of cardiovascular related death and the compromised elastic fiber …

Preclinical Imaging Of Multiple Myeloma Therapy Response, Deep Hathi

McKelvey School of Engineering Graduate Student Theses & Dissertations

Multiple myeloma (MM) is a debilitating hematologic malignancy of terminally differentiated plasma cells in the bone marrow (BM). Advances in therapeutic regimens and the use of autologous stem cell transplantation have significantly improved survival rates and quality of life in patients. However, the disease remains incurable, with shorter, successive remission cycles following relapse. To reduce systemic, off-target toxicity and improve quality of life, there is a need for improved stratification of responding patients. Identification of specific, noninvasive, imaging biomarkers that correlate to therapeutic efficacy is an attractive strategy for stratifying responding patients, since the use of positron emission tomography (PET), …

Simple Surface Modification Of Poly(Dimethylsiloxane) Via Surface Segregating Smart Polymers For Biomicrofluidics, Aslıhan Gökaltun, Young Bok Abraham Kang, Martin L. Yarmush, O. Berk Usta, Ayse Asatekin

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Poly(dimethylsiloxane) (PDMS) is likely the most popular material for microfluidic devices in lab-on-achip and other biomedical applications. However, the hydrophobicity of PDMS leads to non-specific adsorption of proteins and other molecules such as therapeutic drugs, limiting its broader use. Here, we introduce a simple method for preparing PDMS materials to improve hydrophilicity and decrease nonspecific protein adsorption while retaining cellular biocompatibility, transparency, and good mechanical properties without the need for any post-cure surface treatment. This approach utilizes smart copolymers comprised of poly(ethylene glycol) (PEG) and PDMS segments (PDMS-PEG) that, when blended with PDMS during device manufacture, spontaneously segregate to surfaces …

Development Of A Foot Interface To Control Supernumerary Robotics Limbs, Emma Morris

Rose-Hulman Summer Undergraduate Research Fellowships

Supernumerary robotic limbs (SRLs) can be used to provide a person with extra arms to help with difficult tasks. For example, a task that normally requires three hands to complete could be accomplished by just one person with an SRL. One way to control an SRL and still leave both hands available is to use the foot. This paper describes two parts of developing this foot interface: characterizing the range of forces that the foot can apply, and prototyping systems for different control methods. First, a small sample of data was collected to learn how much force the foot can …

Cellular Modification And Artificial Cell Construction, Jimin Guo

Chemical and Biological Engineering ETDs

With all its complexities and different biofunctionalities, a cell is the basic structural and functional unit of all living organisms with the exception of viruses. In this dissertation, I demonstrated gain of function strategies of modifying mammalian cells using silicification and modular nanoparticle (NP) exoskeletons. In addition, I used a modular design concept to build a multifunctional artificial RBC system which can mimic the unique characteristics (e.g. shape, flexibility, the ability to carry oxygen, and long circulation times) of the native RBCs. Together, these cell modification or artificial cell construction strategies are expected to generate new mammalian cell-like structures with …

Identification And Analysis Of Behavioral Phenotypes In Autism Spectrum Disorder Via Unsupervised Machine Learning, Elizabeth Stevens, Dennis R. Dixon, Marlena N. Novack, Doreen Granpeesheh, Tristram Smith, Erik Linstead

Engineering Faculty Articles and Research

Background and objective: Autism spectrum disorder (ASD) is a heterogeneous disorder. Research has explored potential ASD subgroups with preliminary evidence supporting the existence of behaviorally and genetically distinct subgroups; however, research has yet to leverage machine learning to identify phenotypes on a scale large enough to robustly examine treatment response across such subgroups. The purpose of the present study was to apply Gaussian Mixture Models and Hierarchical Clustering to identify behavioral phenotypes of ASD and examine treatment response across the learned phenotypes.

Materials and methods: The present study included a sample of children with ASD (N = 2400), …

The Effect Of Heterobifunctional Crosslinkers On Hema Hydrogel Modulus And Toughness, Elizabeth M. Boazak, Vaughn K. Greene Jr., Debra T. Auguste

Publications and Research

The use of hydrogels in load bearing applications is often limited by insufficient toughness. 2-Hydroxyethyl methacrylate (HEMA) based hydrogels are appealing for translational work, as they are affordable and the use of HEMA is FDA approved. Furthermore, HEMA is photopolymerizable, providing spatiotemporal control over mechanical properties. We evaluated the ability of vinyl methacrylate (VM), allyl methacrylate (AM), and 3-(Acryloyloxy)-2-hydroxypropyl methacrylate (AHPM) to tune hydrogel toughness and Young’s modulus. The crosslinkers were selected due to their heterobifunctionality (vinyl and methacrylate) and similar size and structure to EGDMA, which was shown previously to increase toughness as compared to longer crosslinkers. Vinyl methacrylate …

Using The Xenopus Developmental Eye Regrowth Stystem To Distinguish The Role Of Developmental Versus Regenerative Mechanisms, Cindy X. Kha, Dylan J. Guerin, Kelly Ai-Sun Tseng

Life Sciences Faculty Research

A longstanding challenge in regeneration biology is to understand the role of developmental mechanisms in restoring lost or damaged tissues and organs. As these body structures were built during embryogenesis, it is not surprising that a number of developmental mechanisms are also active during regeneration. However, it remains unclear whether developmental mechanisms act similarly or differently during regeneration as compared to development. Since regeneration is studied in the context of mature, differentiated tissues, it is difficult to evaluate comparative studies with developmental processes due to the latter’s highly proliferative environment. We have taken a more direct approach to study regeneration …

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi S. Patel

University Scholar Projects

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi Patel

Honors Scholar Theses

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

Diagnosing Growth In Low-Grade Gliomas With And Without Longitudinal Volume Measurements: A Retrospective Observational Study., Hassan M Fathallah-Shaykh, Andrew Deatkine, Elizabeth Coffee, Elias Khayat, Asim K Bag, Xiaosi Han, Paula Province Warren, Markus Bredel, John Fiveash, James Markert, Nidhal Carla Bouaynaya, Louis B Nabors

Henry M. Rowan College of Engineering Departmental Research

BACKGROUND: Low-grade gliomas cause significant neurological morbidity by brain invasion. There is no universally accepted objective technique available for detection of enlargement of low-grade gliomas in the clinical setting; subjective evaluation by clinicians using visual comparison of longitudinal radiological studies is the gold standard. The aim of this study is to determine whether a computer-assisted diagnosis (CAD) method helps physicians detect earlier growth of low-grade gliomas.

METHODS AND FINDINGS: We reviewed 165 patients diagnosed with grade 2 gliomas, seen at the University of Alabama at Birmingham clinics from 1 July 2017 to 14 May 2018. MRI scans were collected during …

Energy Expenditure And Stability During Self-Paced Walking On Different Slopes, Alanna Raffaelli

Electronic Theses and Dissertations

Metabolic power and cost of transport (COT) are common quantifiers for effort when performing tasks including walking and running. Most studies focus on using a range of normal walking speeds over level ground or varied slopes. However, these studies use fixed-speed conditions. Fatigue, stability, metabolic expenditure, heart rate, and many other factors contribute to normal walking speed varying over time. This study aimed to show that allowing a subject to walk with a self-paced speed should correlate to a minimum COT at a given slope. This study also aimed to determine if a preferred slope exists based on minimizing metabolic …

Role Of Angiotensin I And Ii On The Tissue Mechanics Of The Aortic Heart Valve Via Receptor Binding And Converting Enzymes, Josh Fahy

Biomedical Engineering Undergraduate Honors Theses

The renin-angiotensin system (RAS) plays a crucial role in the regulation of renal, cardiac, and vascular physiology. This system regulates in vivo blood pressure and fluid balance. As renal blood flow decreases, the kidneys convert prorenin into renin and secrete it into the circulatory system. Renin then converts angiotensinogen into angiotensin I (ang-I). The ang-I is then converted into angiotensin II (ang-II) by the angiotensin-converting enzyme (ACE). Ang-II, a vasoconstrictor, increases blood pressure by causing the blood vessels to narrow. Recent evidence suggests that RAS may be involved in the progression of valve disease, most notably, aortic stenosis.

The first …

Investigation Of Acute Radiation-Induced Changes In Oxygenation In A Murine Breast Tumor Model, Alaa Abdelgawad

Biomedical Engineering Undergraduate Honors Theses

Around 50-60% of all cancer patients undergo radiation therapy. Although some patients show complete response with no recurrence, a significant proportion of the population still develop radiation resistance. It is important to identify tumor resistance at early stages of therapy in order to adjust treatment protocol and avoid extra exposure to radiation. Current methods to assess treatment response are only limited to anatomical measurements of tumor volume after therapy. Novel approaches that shed the light on any functional information during the course of radiotherapy could significantly improve our ability to identify patients who do not respond to radiation therapy. Diffuse …

Mathematical Modeling Of Blood Pressure And Cerebral Blood Flow Using Photoplethysmography Signal, Armin Soltan Zadi

Bioengineering Dissertations - Archive

Continuous and non-invasive monitoring of blood pressure (BP) and cerebral blood flow (CBF) has numerous clinical and health maintenance applications. Of particular interest is monitoring of BP and CBF during events that stress the cardiovascular system such as cessation of breathing during sleep apnea. Current means and methods of continuous measurement of these signals are either invasive or require expensive equipment. Therefore, investigation of new methods of continuous estimation of the BP and CBF are of high interest. One attractive alternative is to use photoplethysmography (PPG) technique to estimate BP and CBF, as PPG is shown to be able to …

The Hip-Spine Effect: How Pathological Femoro-Pelvic Interactions Contribute To Abnormal Lumbar Spine Loading, Anthony Nicholas Khoury

Bioengineering Dissertations - Archive

ABSTRACT THE HIP-SPINE EFFECT: HOW PATHOLOGICAL FEMORO-PELVIC INTERACTIONS CONTRIBUTE TO ABNORMAL LUMBAR SPINE LOADING Anthony Nicholas Khoury, Ph.D. The University of Texas at Arlington, 2019 Supervising Professor: Hal David Martin Cheng-Jen Chuong Lumbar pathology has been shown to explain hip pain, as hip pathology is involved in the development of lumbar pain by the disruption of normal lumbopelvic kinematics. Hip pathologies that contribute to lumbar pain include flexion deformities, osteoarthritis, congenital hip dislocation, and limited hip range of motion. To date there is a paucity of research that actively looks to investigate the symbiotic relationship between the hip and the …