Engineering Commons^™

A Study On The Applications And Toxicity Assessments Of Carbon Nanotubes In Tissue Engineering, Rena Baktur

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Carbon nanotubes (CNTs) are one of the most popular nanomaterials. There has been increasing interest in the development and applications of carbon nanotubes due to their huge potential in industrial and medical applications. Recent applications of carbon nanotubes include development of scaffolds and drug delivery systems. Despite rapidly emerging applications of CNTs, little is known about the impact of CNTs on cellular processes, especially mesenchymal stem cell (MSC)'s differentiation. Also, the effects of nanoparticle exposure under different conditions on cellular responses have not been well characterized yet.

To characterize the effects of CNTs on creating nanoscale scaffolds for tissue engineering, …

Application Of Nanotechnology For Targeted Delivery Of Antibacterial Enzymes And For Enzyme-Based Coatings On Medical Devices And Implants, Rohan Satishkumar

All Dissertations

The frequency of S. aureus infection and subsequent biofilm formation associated with vascular catheterization has been increasing in recent years and often begins as a local colonization at the site of the catheter insertion. Antimicrobial enzymes and peptides, which are effective against a broad range of pathogens and low rates of resistance, have attracted attention as promising alternative candidates in treatment of infections caused by antibiotic resistant bacteria. The use of nanoparticles as carriers for enzymes, in addition to their size, charge, high surface area per volume etc. offers targeted delivery of enzymes to pathogenic bacteria. We proposed to use …

Salen Mn Complexes Mitigate Radiation Injury In Normal Tissues, Rosalind A. Rosenthal, Brian Fish, Richard P. Hill, Karl D. Huffman, Zelmira Lazarova, Javed Mahmood, Meetha Medhora, Robert C. Molthen, John E. Moulder, Stephen T. Sonis, Philip J. Tofilon, Susan R. Doctrow

Biomedical Engineering Faculty Research and Publications

Salen Mn complexes, including EUK-134, EUK-189 and a newer cyclized analog EUK-207, are synthetic SOD/catalase mimetics that have beneficial effects in many models of oxidative stress. As oxidative stress is implicated in some forms of delayed radiation injury, we are investigating whether these compounds can mitigate injury to normal tissues caused by ionizing radiation. This review describes some of this research, focusing on several tissues of therapeutic interest, namely kidney, lung, skin, and oral mucosa. These studies have demonstrated suppression of delayed radiation injury in animals treated with EUK-189 and/or EUK-207. While an antioxidant mechanism of action is postulated, it …

Analysis Of Site-Specific Adjustment Applied To On-The-Go Soil Sensing Data For Agronomic Use, Allison K. Jonjak

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Successful variable-rate applications of agricultural inputs such as lime rely on the quality of input data. Systematic grid soil sampling is the most common method used for creating variable rate prescription maps. The insufficient number of point measurements usually obtained using this method has been primarily responsible for the typical inaccuracies seen in lime prescription maps. To increase sampling density, on-the-go sensing technology was developed for the mapping of soil pH and other relevant attributes. In this study, five fields in eastern Nebraska were mapped using both on-thego sensing technology and systematic grid sampling. Ten calibration points per field were …

Nutrient Runoff Following Manure Application, Chance Thayer

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

A field study was completed to measure the effects of varying flow rate on nutrient transport following the application of varying amounts of beef cattle manure to plots containing either no-residue or a wheat residue cover.  Beef cattle manure was applied and incorporated into the soil in May 2010 to meet zero, one, two, four or eight year corn phosphorus requirements. Simulated rainfall events were applied in June and July 2010. The presence of a crop residue cover significantly increased the transport of dissolved phosphorus, total phosphorus, NO₃-N, NH₄-N, and total nitrogen in runoff but decreased …

Combating Antibiotic Resistance Through Development Of A Novel Antimicrobial Delivery Vehicle, Alex Hatch

Undergraduate Honors Capstone Projects

A thermoreversible gel for antimicrobial agent delivery would provide a novel platform suitable for medical applications from persistent infections arising from localized biofilms. Thermoreversible gels could be used to coat medical implants, to inject for subdermal treatments, or to implement in topical applications. FDA approved Pluronics® form thermoreversible gels and certain Pluronics® display inherent varying degrees of antimicrobial activity. Pluronics® have been shown to affect efflux pumps, and reduce ATP levels within the bacterial cell. In combination with antibiotics and other pharmaceuticals, Pluronics® have been used to sequester drugs and act as a delivery vehicle. With advances in nanomedicine, nanoparticles …

Characterization Of Potential Health Promoting Lipids In The Co-Products Of De-Flossed Milkweed, Vicki Schlegel, Richard Zbasnik, Tammy Gries, Bo Hyun Lee, Timothy Carr, Ji-Young Lee, Curtis Weller, Susan Cuppett

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The floss and oil of the common milkweed (Asclepias syriaca L.) seeds are currently used to produce comforters/pillows and skin care products, respectively. As an outcome of these products, copious quantities co-products (pressed seed meal and pod biomass) are disposed of each year despite the presence of potential health benefiting lipids. The objective of this project was to determine the feasibility of developing the lipid fraction from of these co-products for the fast growing dietary human health market. Although certain types of lipids were affected by the extraction solvent used (hexane and diethyl ether) as were overall amounts, analysis …

Fluoro-Silane As A Functional Monomer For Protein Conformational Imprinting, Yun Peng

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

By using the technology of molecularly imprinted polymer (MIP), we propose to synthesize a protein conformational imprint that also acts as a plastic enzyme, inducing protein structural transitions. The imprint aims at MIP-induced stabilization and / or formation of bound protein secondary structure and the applications associated with analysis and correction of misfolded proteins. The screening of polymeric functional monomers being able to induce the conformational transitions in proteins is investigated in this report.

The fluoro-silanes (3-heptafluoroisopropoxy)propalethoxysilane (7F) and 3,3,3-trifluoropropylmethoxysilane (3F) were employed as functional monomers for synthesis of this catalytic protein conformational imprint via sol-gel reactions. 3F was demonstrated …

Methods Development And Force Field Evaluation For Molecular Simulations Of Interactions Between Structured Peptides And Functionalized Material Surfaces, Galen Collier

All Dissertations

The process of protein adsorption to material surfaces is highly complex and it is one of the most fundamental concepts upon which progress in the field of bioengineering is based. The strategic design of material surfaces for optimal utility in specific biological environments is absolutely dependent upon a thorough understanding of the mechanisms underlying protein adsorption, yet there is still a very limited understanding of these mechanisms. The primary reason for this lack of understanding is that protein adsorption is a dynamic process which occurs at the atomic and macromolecular scale, where experimental analyses provide a view that is static …

Biokinetic Mechanisms Linked With Musculoskeletal Health Disparities: Stochastic Models Applying Tikhonov's Theorem To Biomolecule Homeostasis., Asit K. Saha, Yu Liang, Sean S. Kohles

Mechanical and Materials Engineering Faculty Publications and Presentations

Multiscale technology and advanced mathematical models have been developed to control and characterize physicochemical interactions, respectively, enhancing cellular and molecular engineering progress. Ongoing tissue engineering development studies have provided experimental input for biokinetic models examining the influence of static or dynamic mechanical stimuli (Saha, A. K., and Kohles, S. S., 2010, “A Distinct Catabolic to Anabolic Threshold Due to Single-Cell Nanomechanical Stimulation in a Cartilage Biokinetics Model,” J. Nanotechnol. Eng. Med., 1(3) p. 031005; 2010, “Periodic Nanomechanical Stimulation in a Biokinetics Model Identifying Anabolic and Catabolic Pathways Associated With Cartilage Matrix Homeostasis,” J. Nanotechnol. Eng. Med., 1(4), p. 041001). In …

Investigation Of A Simulated Annealing Cooling Schedule Used To Optimize The Estimation Of The Fiber Diameter Distribution In A Peripheral Nerve Trunk, Arya Vigeh

Master's Theses

In previous studies it was determined that the fiber diameter distribution in a peripheral nerve could be estimated by a simulation technique known as group delay. These results could be further improved using a combinatorial optimization algorithm called simulated annealing. This paper explores the structure and behavior of simulated annealing for the application of optimizing the group delay estimated fiber diameter distribution. Specifically, a set of parameters known as the cooling schedule is investigated to determine its effectiveness in the optimization process.

Simulated annealing is a technique for finding the global minimum (or maximum) of a cost function which may …

Novel Nanofiber Structures And Advanced Tissue Engineering Applications, Vince Beachley

All Dissertations

Extracellular matrix (ECM) nanofibers such as collagen and elastin make up an important component of natural tissues. These structural components serve to impart mechanical strength and provide locations for cell attachment and biomolecule storage. Cells respond to their structural environment in a wide variety of ways beyond physical support, and it has been demonstrated that this environment directly modulates cell behaviors such as, morphology, differentiation, ECM production, attachment, and migration. ECM nanofibers also play an important role as a template for tissue formation during development, remodeling, and regeneration. Nanofiber based tissue engineering strategies aim to mimic the geometry of the …

A Rapid And Computationally Inexpensive Method To Virtually Implant Current And Next-Generation Stents Into Subject-Specific Computational Fluid Dynamics Models, Timothy J. Gundert, Shawn C. Shadden, Andrew R. Williams, Bon-Kwon Koo, Jeffrey A. Feinstein, John F. Ladisa

Biomedical Engineering Faculty Research and Publications

Computational modeling is often used to quantify hemodynamic alterations induced by stenting, but frequently uses simplified device or vascular representations. Based on a series of Boolean operations, we developed an efficient and robust method for assessing the influence of current and next-generation stents on local hemodynamics and vascular biomechanics quantified by computational fluid dynamics. Stent designs were parameterized to allow easy control over design features including the number, width and circumferential or longitudinal spacing of struts, as well as the implantation diameter and overall length. The approach allowed stents to be automatically regenerated for rapid analysis of the contribution of …

Design And Implementation Of An Eye Blink Controlled Human Computer Interface, Poonam Gwalani

Theses and Dissertations

Advances in Human Computer Interface (HCI) have made this area of research important for improving the standard of living for people with disabilities. An eye blink system is presented to allow people with disabilities to control a standard computer mouse. This system is designed for people who are paralytic with no control over their arms, speech, and anyone who is restricted to only the control of eye and head movements. This system is based on infrared reflectivity to capture and analyze real time eye blink signal of the user. It uses simple economical hardware electronics to emulate the functionality of …

3d Functional Modeling Of Dbs Efficacy And Development Of Analytical Tools To Explore Functional Stn, Deepak Kumbhare

Theses and Dissertations

Introduction: Exploring the brain for optimal locations for deep brain stimulation (DBS) therapy is a challenging task, which can be facilitated by analysis of DBS efficacy in a large number of patients with Parkinson’s disease (PD). The Unified Parkinson's Disease Rating Scale (UPDRS) scores indicate the DBS efficacy of the corresponding stimulation location in a particular patient. The spatial distribution of these clinical scores can be used to construct a functional model which closely models the expected efficacy of stimulation in the region. Designs and Methods: In this study, different interpolation techniques were investigated that can appropriately model the DBS …

Construction And Use Of A Direct Calorimeter To Estimate Energy Expenditure In Hibernators, Mark S. Burger, Frank Van Breukelen

Festival of Communities: UG Symposium (Posters)

Metabolic rates have traditionally been estimated through indirect calorimetry (gas exchange or respirometry) due to its ease and availability. Oxygen consumption neglects the contributions of anaerobic metabolism, while direct calorimetry (heat production) estimates both anaerobic and aerobic metabolism. Walsberg and Hoffman (2005) report anaerobic metabolism may be more important to small rodents than was previously thought. During the non-steady state of mammalian hibernation, we hypothesize that anaerobic processes may play an even greater role in fueling metabolism. To address this question, we constructed a very sensitive calorimeter that utilizes the Seebeck effect from a thermoelectric element (Peltier device). We describe …

Dual-Channel Imaging System For Singlet Oxygen And Photosensitizer For Pdt, Seonkyung Lee, Martin E. Isabelle, Kristin L. Gabally-Kinney, Brian W. Pogue, Steven J. Davis

Dartmouth Scholarship

A two-channel optical system has been developed to provide spatially resolved simultaneous imaging of singlet molecular oxygen (¹O₂) phosphorescence and photosensitizer (PS) fluorescence produced by the photodynamic process. The current imaging system uses a spectral discrimination method to differentiate the weak ¹O₂ phosphorescence that peaks near 1.27 μ m from PS fluorescence that also occurs in this spectral region. The detection limit of ¹O₂ emission was determined at a concentration of 500 nM benzoporphyrin derivative monoacid (BPD) in tissue-like phantoms, and these signals observed were proportional to the PS fluorescence. Preliminary in …

Mitochondrial Approaches To Protect Against Cardiac Ischemia And Reperfusion Injury, Amadou K.S. Camara, Martin Bienengraeber, David F. Stowe

Biomedical Engineering Faculty Research and Publications

The mitochondrion is a vital component in cellular energy metabolism and intracellular signaling processes. Mitochondria are involved in a myriad of complex signaling cascades regulating cell death vs. survival. Importantly, mitochondrial dysfunction and the resulting oxidative and nitrosative stress are central in the pathogenesis of numerous human maladies including cardiovascular diseases, neurodegenerative diseases, diabetes, and retinal diseases, many of which are related. This review will examine the emerging understanding of the role of mitochondria in the etiology and progression of cardiovascular diseases and will explore potential therapeutic benefits of targeting the organelle in attenuating the disease process. Indeed, recent advances …

Gas Embolic Factors In Cardiovascular Health, Eric L. Cutler

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

Gas emboli are a clinical issue often encountered in the space exploration, marine construction, and medical fields.  Individuals involved with these disciplines will often have asympomatic gas emboli circulating throughout their bodies on a regular basis.  A study into the impact of chronic asymptomatic gas emboli on the risk of atherosclerosis in humans is thus presented.  This research utilized a custom built cardiovascular flow simulator and accompanying data acquisition system to experimentally determine the influence of gas emboli under varied circumstances on the mean wall shear stress of a tube in-vitro.  A directly inverse relationship between gas embolus presence in …

Quantitative Reappraisal Of The Helmholtz-Guyton Resonance Theory Of Frequency Tuning In The Cochlea, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

To explore the fundamental biomechanics of sound frequency transduction in the cochlea, a two-dimensional analytical model of the basilar membrane was constructed from first principles. Quantitative analysis showed that axial forces along the membrane are negligible, condensing the problem to a set of ordered one-dimensional models in the radial dimension, for which all parameters can be specified from experimental data. Solutions of the radial models for asymmetrical boundary conditions produce realistic deformation patterns. The resulting second-order differential equations, based on the original concepts of Helmholtz and Guyton, and including viscoelastic restoring forces, predict a frequency map and amplitudes of deflections …

Manipulating Cellular Growth Responses To Patterning, Apoptotic, And Environmental Cues, James N. Mcnamara

Doctoral Dissertations

In this work, various methods of controlling cell growth are examined. Cell-cell interaction, apoptotic cues, three dimensional scaffolds, and non-adherent environments are evaluated for their ability to affect the differentiation, morphology, and growth rate of different cell types. Previous work has shown that cell growth and cell morphology can be influenced by patterns of polymers coated on surfaces in two dimensions, designated here as the x and y dimensions of a standard Cartesian coordinate system. Tissue engineering and regenerative medicine studies have shown limited success in modifying growth in the third, z dimension. This work considers not only the x, …

Ultrasonic Assisted Layer-By-Layer Assembly For Stable Nanocolloids Of Curcumin And Paclitaxel, Zhiguo Zheng

Doctoral Dissertations

Researchers have been trying to fight cancer with synthesis of new bioactive compounds but many of these novel drugs have low solubility in water and it is difficult to deliver them into a patient's body. One way of solving this particular problem is to use nanoscale drug delivery systems. In this dissertation, we describe using an ultrasonic assisted layer-by-layer encapsulation process to prepare anti-cancer drugs with 50∼200 nm particle size with designed coating to achieve sustained release and target delivery.

Two methods for systematic manufacture of low solubility anti-cancer drug nanoparticles were proposed: I) Top-down approach to breakdown larger drug …

The Effect Of Maternal Diet On Fetal Development, Catherine Wilcox

Renée Crown University Honors Thesis Projects - All

Using mice as a model system, this study aimed to compare the effect of a high fat diet (HFD), high sugar diet (HSD) and a control diet (CD) on fetal growth and development at the time of birth (post-natal day 0 or PND 0), post-natal day 7 (PND 7) and post-natal day 14 (PND 14). Published literature has documented the effects of a negative in-utero environment on fetal development, but currently there is limited research regarding the continued effects on development after birth. Mouse pups were harvested and then imaged in 3-D using a high-resolution micro-computed tomography (micro-CT) system. Total …

Section Abstracts: Biomedical And General Engineering

Virginia Journal of Science

Abstracts of the Biomedical and General Engineering Section for the 89th Annual Meeting of the Virginia Academy of Science, May 25-27, 2011, University of Richmond, Richmond VA.

Leaching Of Potential Hazardous Elements Of Coal Cleaning Rejects, Luis F.O. Silva, Maria Izquierdo, Xavier Querol, Robert B. Finkelman, Marcos L.S. Oliveira, Marcus Wollenschlager, Mark R. Towler, Rafael Pérez-López, Felipe Macias

Chemical and Biochemical Engineering Faculty Research & Creative Works

The geochemical characteristics of coal cleaning rejects (CCR) in Santa Catarina State, Brazil, were investigated. Around 3.5 million ton/ year of coal waste are dumped in Santa Catarina State. Coal beneficiation by froth flotation results in large amounts of CCR composed of coaly and mineral matter, the latter characterized by the occurrence of sulphide minerals and a broad array of leachable elements. The total and leachable contents of more than 60 elements were analyzed. Atmospheric exposure promotes sulphide oxidation that releases substantial sulphate loads as well as Ca²⁺, K⁺, Mg²⁺, Cl- and Al^{3+ …}

Design And Development Of Two Test Fixtures To Test The Longitudinal And Transverse Tensile Properties Of Small Diameter Tubular Polymers, Carolyn Berry

Master's Theses

Hundreds of thousands of vascular bypass grafts are implanted in the United States every year, but there has yet to be an ideal graft material to substitute for one’s own autologous vessel. Many synthetic materials have been shown to be successful vessel replacements; however, none have been proven to exhibit the same mechanical properties as native vessels, one of the most important criteria in selecting a vascular graft material. Part of this issue is due to the fact that, currently, there is no “gold standard” for testing the longitudinal and transverse tensile properties of small diameter tubular materials. While there …

Ultrasonic And Stereo-Optical Characterization Techniques For Applications In Mechanical Testing, Jonathan M. Hein

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

This thesis considers methods developed based on ultrasonic reflections from interfaces and stereo-optical surface strain measurements to study the mechanical characterization of materials and bodies. The ultrasonic method is used to characterize wave speed and attenuation for highly attenuating samples. The stereo-optical strain measurements are used to characterize the effects of genes on mechanical properties of bone, and the dynamic characterization of blast waves in the UNL Shock Wave Trauma Mechanics facility.

A method is described and developed for characterizing the wave speed and attenuation spectrums from reflected waves from the contact surface with an unknown material. The method is …

The Dominant Role Of The Hip In Multijoint Reflex Responses In Human Spinal Cord Injury, Tanya Onushko

Dissertations (1934 -)

Following a spinal cord injury (SCI), people often experience exaggerated reflexes, such that mild provocations can cause prolonged and uncontrolled muscle activity throughout the entire leg. These reflexes can be problematic and are known to interfere with functional tasks, such as transferring to and from a wheelchair, and they may interfere with locomotor function by prolonging muscle activity and/or inappropriately activating muscles during attempts to walk. While these multijoint reflexes have been shown to originate from several afferent cues, hip afferent input is a particularly potent sensory signal that readily triggers multijoint reflexes. The overall objective of this dissertation was …

Evaluation Of A Novel Non-Penetrating Electrode For Use In Dna Vaccination, Amy Donate, Domenico Coppola, Yolmari Cruz, Richard Heller

Bioelectrics Publications

Current progress in the development of vaccines has decreased the incidence of fatal and non-fatal infections and increased longevity. However, new technologies need to be developed to combat an emerging generation of infectious diseases. DNA vaccination has been demonstrated to have great potential for use with a wide variety of diseases. Alone, this technology does not generate a significant immune response for vaccination, but combined with delivery by electroporation (EP), can enhance plasmid expression and immunity. Most EP systems, while effective, can be invasive and painful making them less desirable for use in vaccination. Our lab recently developed a non-invasive …

Learning Feature Dependencies For Noise Correction In Biomedical Prediction, Ghim-Eng Yap, Ah-Hwee Tan, Hwee Hwa Pang

Research Collection School Of Computing and Information Systems

The presence of noise or errors in the stated feature values of biomedical data can lead to incorrect prediction. We introduce a Bayesian Network-based Noise Correction framework named BN-NC. After data preprocessing, a Bayesian Network (BN) is learned to capture the feature dependencies. Using the BN to predict each feature in turn, BN-NC estimates a feature's error rate as the deviation between its predicted and stated values in the training data, and allocates the appropriate uncertainty to its subsequent findings during prediction. BN-NC automatically generates a probabilistic rule to explain BN prediction on the class variable using the feature values …