Biomedical Engineering and Bioengineering Commons^™

Algal Biofilm Production And Harvesting System For Wastewater Treatment With Biofuels By-Products, Logan Christenson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Excess nitrogen and phosphorus in discharged wastewaters can lead to downstream eutrophication, ecosystem damage, and impaired water quality that may affect human health. Chemical-based and physical-based technologies are available to remove these nutrients; however, they often consume significant amounts of energy and chemicals, greatly increasing treatment costs. Algae are capable of removing these pollutants through biomass assimilation, and if harvested, can be utilized as a feedstock for biomethane or biodiesel production. Currently, difficulties in harvesting, concentrating, and dewatering algae have limited the development of an economically feasible treatment and production process. When algae are grown as surface-attached biofilms, the biomass …

Characterization And Application Of Dynamic In Vitro Models Of Human Airway, Hemangkumar J. Patel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In recent years, respiratory diseases have emerged as a leading cause of mortality across the globe. In the United States alone respiratory diseases are the fourth leading cause of deaths annually. Moreover, with the rapid increase of industrialization and urbanization, the occurrences of respiratory diseases are expected to remain high with strong chances of increasing in the future. To ameliorate the epidemic of respiratory disease, it is first important to understand its underlying mechanisms.

Respiratory research studies in animals have elucidated the chronological order of the pathological events and systemic responses inside the lung, but understanding the response of individual …

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, …

What Is Inverse-Geometry Ct?, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Inverse-geometry computed tomography (IGCT) systems are being developed to provide improved volumetric imaging. In conventional multislice CT systems, x-rays are emitted from a small area and irradiate a large-area detector. In an IGCT system, x-ray sources are distributed over a large area, with each beam irradiating a small-area detector. Therefore, in the inverse geometry, a series of narrow x-ray beams are switched on and off while the gantry rotates. In conventional CT geometry, cone-beam and scatter artifacts increase with the imaged volume thickness. An inverse geometry may be less susceptible to scatter effects, because only a fraction of the field …

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 …

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 …

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 …

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 …