Biomedical Engineering and Bioengineering Commons^™

Mechanical Characterization Of Fourth Generation Composite Humerus, Prateek Grover, Carolyne Albert, Mei Wang, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Mechanical data on upper extremity surrogate bones, supporting use as biomechanical tools, is limited. The objective of this study was to characterize the structural behaviour of the fourth-generation composite humerus under simulated physiologic bending, specifically, stiffness, rigidity, and mid-diaphysial surface strains. Three humeri were tested in four-point bending, in anatomically defined anteroposterior (AP) and mediolateral (ML) planes. Stiffness and rigidity were derived using load–displacement data. Principal strains were determined at the anterior, posterior, medial, and lateral surfaces in the humeral mid-diaphysial transverse plane of one specimen using stacked rosettes. Linear structural behaviour was observed within the test range. Average stiffness …

Designing Predictive Mathematical Models For The Metabolic Pathways Associated With Polyhydroxybutyrate Synthesis In Escherichia Coli, Angela Dixon

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plastics are a versatile and widely used material. However, traditional plastics are derived from petrochemicals and are not biodegradable. Polymers synthesized from microorganisms that have similar properties to plastic are potential biodegradable replacements. The objective of this project is to use mathematical modeling as a tool to engineer a strain of bacteria optimized for the production of bio-plastics.

Production costs can be reduced by using a bacterial strain specifically optimized for bio-plastic production. By reducing production costs, bio-plastics will be able to commercially compete with traditional plastics. Society will benefit as bio-plastics replace traditional plastics. Fossil fuels will not be …

Field-Controlled Electron Transfer And Reaction Kinetics Of The Biological Catalytic System Of Microperoxidase-11 And Hydrogen Peroxide, Yongki Chou, Siu-Tung Yau

Electrical and Computer Engineering Faculty Publications

Controlled reaction kinetics of the bio-catalytic system of microperoxidase-11 and hydrogen peroxide has been achieved using an electrostatic technique. The technique allowed independent control of 1) the thermodynamics of the system using electrochemical setup and 2) the quantum mechanical tunneling at the interface between microperoxidase-11 and the working electrode by applying a gating voltage to the electrode. The cathodic currents of electrodes immobilized with microperoxidase-11 showed a dependence on the gating voltage in the presence of hydrogen peroxide, indicating a controllable reduction reaction. The measured kinetic parameters of the bio-catalytic reduction showed nonlinear dependences on the gating voltage as the …

'Exploring The Potential Of Using Antimicrobial Peptides And Copper Nanoparticles In Tackling Surgical Site Infections', Sriram Sankar

All Theses

Postoperative wound site infections remain a major source of illness with approximately 500,000 infections per year, among an estimated 27 million surgical procedures. Such infections account for approximately one quarter of the estimated 2 million nosocomial infections in the United States which causes about 90,000 deaths each year. More than 70% of the bacteria that causes such infections are resistant to at least one of the antibiotics and result in longer hospitalization; besides requiring second option treatments that may be less effective, more toxic and expensive. Hence, there is a frenetic search for alternatives and in this regard, antimicrobial peptides …

Dna Electrophoretic Migration Patterns Change After Exposure Of Jurkat Cells To A Single Intense Nanosecond Electric Pulse, Stefania Romeo, Luigi Zeni, Maurizio Sarti, Anna Sannino, Maria Rosaria Scarfi, P. Thomas Vernier, Olga Zeni

Bioelectrics Publications

Intense nanosecond pulsed electric fields (nsPEFs) interact with cellular membranes and intracellular structures. Investigating how cells respond to nanosecond pulses is essential for a) development of biomedical applications of nsPEFs, including cancer therapy, and b) better understanding of the mechanisms underlying such bioelectrical effects. In this work, we explored relatively mild exposure conditions to provide insight into weak, reversible effects, laying a foundation for a better understanding of the interaction mechanisms and kinetics underlying nsPEF bio-effects. In particular, we report changes in the nucleus of Jurkat cells (human lymphoblastoid T cells) exposed to single pulses of 60 ns duration and …

Design And Fabrication Of Nanofluidic Systems For Biomolecule Characterizations, Orain Ansel Hibbert

Graduate Theses and Dissertations

Nanofluidic channel systems were designed and fabricated by combining MEMS microfabrication with AFM nanolithography. In the fabrication process flow, photolithography was first utilized to pattern microfluidic channels and reservoirs on a 4" Pyrex substrate. Subsequently, atomic force microscopy (AFM) based nanolithography was used to mechanically fabricate nanochannels to connect the microreservoirs which formed the inlet and outlet of the nanofluidic system. A Tap190 Diamond-Like Carbon (DLC) AFM tip with a force constant of 48 N/m and a radius of less than 15 nm was used as the nanolithography tool. The resultant nanochannel ranges from 20 to 80 µm in length …

Interfacial Force Field Parameterization Using The Dual Force Field Charmm Program For The Accurate Simulation Of Peptide-Surface Interaction, Nadeem Vellore

All Dissertations

Protein adsorption to solid material surfaces is a complex phenomenon and various factors play a role in controlling these processes. Inherent limitations to understand these biological interactions using experimental approaches alone have led to the possibility of exploring these systems using computational molecular simulation methodologies. Before confidence can be placed on these computational protocols, however, rigorous validation of the applicability of these methods to accurately represent protein adsorption processes is needed. In this research, we evaluated the use of all-atom empirical force field (FF) based simulations using the CHARMM simulation program and FF for the study of peptide adsorption processes …

Development Of A Dynamic In Vitro Model Of A Stented Blood Vessel To Evaluate The Effects Of Stent Strut Material Selection And Surface Coating On Smooth Muscle Cell Response, Bradley Winn

All Dissertations

Cardiovascular disease is the leading cause of mortality in The United States and Europe, accounting for approximately half of all deaths. The most common form of cardiovascular disease is atherosclerosis, which is characterized by the formation of fatty atheromatous plaques that can grow to occlude the vessel lumen, thus causing ischemia distal to the occlusion. This is commonly treated using balloon angioplasty, which is usually done in conjunction with the deployment of a stent. Stent deployment helps hold the vessel open following the local injury caused by balloon inflation and prevents elastic recoil and subsequent negative remodeling. Stenting has been …

Electrical Coupling Between Micropatterned Cardiomyocytes And Stem Cells, Zhen Ma

All Dissertations

To understand how stem cells functionally couple with native cardiomyocytes is crucial for cell-based therapies to restore the loss of cardiomyocytes that occurs during heart infarction and other cardiac diseases. Due to the complexity of the in vivo environment, our knowledge of cell coupling is heavily dependent on cell-culture models. However, conventional in vitro studies involve undefined cell shapes and random length of cell-cell contacts in addition to the presence of multiple homotypic and heterotypic contacts between interacting cells. Thus, it has not been feasible to study electrical coupling corresponding to isolated specific types of cell contact modes.
To address …

Characterizing Mechanical Heterogeneity In Cardiovascular Cells, Sandra Deitch

All Dissertations

Most tissue-level mechanical models assume homogeneous mechanical properties within a single cell type. However, measurements of cellular mechanical properties show large variability in whole-cell mechanical properties between cells from a single population. This heterogeneity has been observed in many cell populations and with several measurement techniques but the sources are not yet fully understood. Cell mechanical properties are directly related to the composition and organization of the cytoskeleton, which is physically coupled to neighboring cells through adherens junctions and to underlying matrix scaffolds through focal adhesion complexes. As such, we believe that this high level of heterogeneity can be attributed …

Different Motion Cues Are Used To Estimate Time-To-Arrival For Frontoparallel And Loming Trajectories, Finnegan J. Calabro, Scott A. Beardsley, Lucia M. Vaina

Biomedical Engineering Faculty Research and Publications

Estimation of time-to-arrival for moving objects is critical to obstacle interception and avoidance, as well as to timing actions such as reaching and grasping moving objects. The source of motion information that conveys arrival time varies with the trajectory of the object raising the question of whether multiple context-dependent mechanisms are involved in this computation. To address this question we conducted a series of psychophysical studies to measure observers’ performance on time-to-arrival estimation when object trajectory was specified by angular motion (“gap closure” trajectories in the frontoparallel plane), looming (colliding trajectories, TTC) or both (passage courses, TTP). We measured performance …

A Novel Telecommunications-Based Approach To Mathematical Modeling Of Hiv Infection, Aaron T. Sharp

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

It is well known that biological systems utilize communication in some form, one prolific example of this is the propagation of HIV (Human Immunodeficiency Virus) in the human body. By modeling HIV infection as a communication system, we hope to gain a unique insight into HIV and biological communication systems in general. Such a model would provide researchers a platform for experimenting and simulating various biological communication systems. We have previously developed a layered communication protocol for interpreting biological communication systems using telecommunications paradigms and will apply said model to HIV proliferation. We will also demonstrate the effectiveness of the …

Impedance-Based Detection Of Tissue Using A Multi-Electrode Device, Shane Killian Fleshman

Master's Theses

Melanoma skin cancer is the abnormal growth of the melanocytes – the pigmented cells located in the epidermis. The current gold standard diagnostic technique for determining whether a lesion is cancerous involves subjectively examining suspicious lesions and performing an invasive biopsy to confirm melanoma. This method may neglect some lesions or cause scarring from biopsies that turn out to be benign. Thus, impedance-based detection using a multi-electrode device was investigated as a noninvasive technique to diagnose melanoma skin cancer. The multi-electrode device was designed with 8 equally spaced Ag/AgCl electrodes surrounding one central electrode at a 5 mm radius. The …

Seasonal And Anatomical Variation In Compact Bone Remodeling In The Adult Sheep, Joseph Calcagno

Master's Theses

ABSTRACT

SEASONAL AND ANATOMICAL VARIATION IN COMPACT BONE REMODELING IN THE ADULT SHEEP

Joseph Calcagno

In order to determine whether ovine compact bone is suitable for study of osteoporosis, the remodeling parameters of the untreated animal must be fully characterized. Ovine compact bone is an attractive large animal model due to its similarities in size and bone remodeling to humans. However hormonal, exercise, and dietary changes due to seasonal changes can cause treatment effects to be hidden or superimposed on existing changes in the bone. In order to determine if any seasonal or anatomical variation occurred in the compact bone …

Directed Evolution Of Adeno-Associated Virus For Enhanced Gene Delivery And Gene Targeting In Human Pluripotent Stem Cells, Prashanth Asuri, Melissa Bartel, Tandis Vazin, Jae-Hyung Jang, Tiffany Wong, David Schaffer

Bioengineering

Efficient approaches for the precise genetic engineering of human pluripotent stem cells (hPSCs) can enhance both basic and applied stem cell research. Adenoassociated virus (AAV) vectors are of particular interest for their capacity to mediate efficient gene delivery to and gene targeting in various cells. However, natural AAV serotypes offer only modest transduction of human embryonic and induced pluripotent stem cells (hESCs and hiPSCs), which limits their utility for efficiently manipulating the hPSC genome. Directed evolution is a powerful means to generate viral vectors with novel capabilities, and we have applied this approach to create a novel AAV variant with …

Tissue Engineering An Acellular Bioresorbable Vascular Graft To Promote Regeneration, Patricia Wolfe

Theses and Dissertations

Tissue engineering is an interdisciplinary field that aims to restore, maintain, or improve diseased or damaged tissues. Electrospinning has become one of the most popular means to fabricate a scaffold for various tissue engineering applications as the process is extremely versatile and inexpensive. The ability for electrospinning to consistently create nanofibrous structures capable of mimicking the native extracellular matrix (ECM) is the basis behind why this technique is so successful in tissue engineering. Cardiovascular disease has been the leading cause of death in the United States for over 100 years, and because of this, the need for coronary artery replacements …

Differential Gene Expression To Investigate The Effects Of Low-Level Electrochemical Currents On Bacillus Subtilis., Robert Szkotak, Tagbo H R Niepa, Nikhil Jawrani, Jeremy L. Gilbert, Marcus B. Jones, Dacheng Ren

Biomedical and Chemical Engineering - All Scholarship

With the emergence and spread of multidrug resistant bacteria, effective methods to eliminate both planktonic bacteria and those embedded in surface-attached biofilms are needed. Electric currents at uA-mA/cm2 range are known to reduce the viability of bacteria. However, the mechanism of such effects is still not well understood. In this study, Bacillus subtilis was used as the model Gram-positive species to systematically investigate the effects of electrochemical currents on bacteria including the morphology, viability, and gene expression of planktonic cells, and viability of biofilm cells. The data suggest that weak electrochemical currents can effectively eliminate B. subtilis both as planktonic …

Migration And Invasion Of Brain Tumors, Richard A. Able, Jr., Veronica Dudu, Maribel Vazquez

Publications and Research

Recent advances in molecular biology have led to new insights in the development, growth and infiltrative behaviors of primary brain tumors (Demuth and Berens, 2004; Huse and Holland, 2010; Johnson et al., 2009; Kanu et al., 2009). These tumors are derived from various brain cell lineages and have been historically classified on the basis of morphological and, more recently, immunohistochemical features with less emphasis on their underlying molecular pathogenesis (Huse and Holland, 2010). The detailed molecular characterization of brain tumors has laid the groundwork for augmentation of standard treatment with patient-specific designed targeted therapies (Johnson et al., 2009; Kanu et …

Differential Il-21 Signaling In Apcs Leads To Disparate Th17 Differentiation In Diabetes-Susceptible Nod And Diabetes-Resistant Nod.Idd3 Mice., Sue M. Liu, David H. Lee, Jenna M. Sullivan, Denise Chung, Anneli Jäger, Bennett O V. Shum, Nora E. Sarvetnick, Ana C. Anderson, Vijay K. Kuchroo

Journal Articles: Regenerative Medicine

Type 1 diabetes (T1D) is an autoimmune disease that shows familial aggregation in humans and likely has genetic determinants. Disease linkage studies have revealed many susceptibility loci for T1D in mice and humans. The mouse T1D susceptibility locus insulin-dependent diabetes susceptibility 3 (Idd3), which has a homologous genetic interval in humans, encodes cytokine genes Il2 and Il21 and regulates diabetes and other autoimmune diseases; however, the cellular and molecular mechanisms of this regulation are still being elucidated. Here we show that T cells from NOD mice produce more Il21 and less Il2 and exhibit enhanced Th17 cell generation compared with …

Unstable Spinocerebellar Ataxia Type 10 (Attct) (Agaat) Repeats Are Associated With Aberrant Replication At The Atx10 Locus And Replication Origin-Dependent Expansion At An Ectopic Site In Human Cells, Guoqi Liu, John J. Bissler, Richard R. Sinden, Michael Leffak

Biomedical Engineering and Sciences Faculty Publications

Spinocerebellar ataxia type 10 (SCA10) is associated with expansion of (ATTCT)n repeats (where n is the number of repeats) within the ataxin 10 (ATX10/E46L) gene. The demonstration that (ATTCT)n tracts can act as DNA unwinding elements (DUEs) in vitro has suggested that aberrant replication origin activity occurs at expanded (ATTCT)n tracts and may lead to their instability. Here, we confirm these predictions. The wild-type ATX10 locus displays inefficient origin activity, but origin activity is elevated at the expanded ATX10 loci in patient-derived cells. To test whether (ATTCT)n tracts can potentiate origin activity, cell lines were constructed that contain ectopic copies …