Biomedical Commons^™

Manufacturing Nerve Guidance Conduits By Stereolithography For Use In Peripheral Nerve Regeneration, Mireya Aidee Perez

Open Access Theses & Dissertations

Nerve regeneration techniques have been studied in great depth in recent years. Peripheral nerve injuries, in particular, can be caused by accidents, falls, athletic injuries, etc. Current methods of repair include direct suturing of the 2 injured nerve ends or the use of autografts, when a nerve section is taken from another area of the body. Both methods have a series of limitations which have led researchers to study alternative methods of repair. Nerve guidance conduits may provide a viable solution because they can be modified and adapted to the patient's needs. Some conduits already exist on the market and …

Printable Biodegradable Hydrogel For Skin Wound Dressing Using Inkjet Printing Technology, Maria G. Yanez

Open Access Theses & Dissertations

Chronic wounds are becoming more frequent. Foot ulcers affect approximately 10% - 15% of patients with diabetes throughout their lifetimes, and by 2025, it is estimated the prevalence of diabetes will be 250 million people in the worldwide. There is increased potential for patients with peripheral neuropathy and peripheral vascular disease to suffer more foot injuries. These conditions reduce the normal pain sensations and healing of minor traumas, allowing the development of chronic non-healing ulcers, often preceding lower-extremity amputation. These types of wounds are very difficult to treat and sometimes take months or even years to heal because of many …

Tpm: Cloud-Based Tele Ptsd Monitor Using Multi-Dimensional Information, Roger Xu, Gang Mei, Guangfan Zhang, Pan Gao, Aaron Pepe, Jiang Li, James D. Westwood (Ed.), Susan W. Westwood (Ed.), Li Felländer-Tsai (Ed.), Randy S. Haluck (Ed.), Richard A. Robb (Ed.), Steven Senger (Ed.), Kirby G. Vosburgh (Ed.)

Electrical & Computer Engineering Faculty Publications

An automated system that can remotely and non-intrusively screen individuals at high risk for Post-Traumatic Stress Disorder (PTSD) and monitor their progress during treatment would be desired by many Veterans Affairs (VAs) as well as other PTSD treatment and research organizations. In this paper, we present an automated, cloud-based Tele-PTSD Monitor (TPM) system based on the fusion of multiple sources of information. The TPM system can be hosted in a cloud environment and accessed through landline or cell phones, or on the Internet through a web portal or mobile application (app).

Effects Of Blood Flow On The Heating Of Cardiac Stents Due To Radio Frequency Fields, Nate Ian Elder

Open Access Theses

A safety concern during MRI scans with implanted medical devices is heating induced by the incident RF field. This research was performed to better understand the heating of cardiac stents during MRI. Heating of cardiac stents tends to occur at their ends. The temperature rise will be affected by blood flow through the lumen of the stent. In this work, an experiment was performed to simulate heating of a cardiac stent in the presence of blood flow during exposure to the electric field induced by a 64 MHz magnetic field, which corresponds to MRI at 1.5 T. The test procedure …

Vibrational Photoacoustic Tomography: Deep Tissue Imaging With Biomarker Sensitivity, Rui Li

Open Access Theses

As a molecular and functional imaging modality, photoacoustic imaging has been applied to animals or human organs such as breast, brain and skin. Till now, the contrast mechanism of photoacoustic imaging is mainly based on electronic absorption in visible and near infrared region. Inherent molecular vibration offers a contrast mechanism for chemical imaging in a label free manner. In vibrational microscopy based on either infrared absorption or Raman scattering, the imaging depth is limited to the ballistic photon mean free path, which is a few hundred microns in a biological sample. Owing to much weaker acoustic scattering in tissues as …

The Perceptual Salience Of Amplitude Modulated Cortical Stimulation: Peak Equivalence Or Rms Equivalence?, Oliver Brian Regele

Open Access Theses

Intracortical microstimulation (ICMS) is a method of electrically stimulating the primary motor, visual, somatosensory and auditory cortices in the brain. The goal is to replace deficient sensory function in cases such as deafness, blindness and paralysis. However these neural prosthetics have not made the full transition to clinical trials due to a lack of sufficient investigation into the optimal stimulation waveforms. Sinusoidally amplitude modulated (SAM) signals have been shown to be important to sensory systems, yet have not been fully explored as a stimulation waveform for stimulating cortical tissue.

This work represents an investigation into the detection characteristics of electrical …

Modulation Of Cell-Matrix Interaction For Cryopreservation Of Engineered Tissue, Angela Christine Seawright

Open Access Theses

Long term preservation of functional engineered tissues can significantly advance tissue engineering industry and regenerative medicine. Several preservation techniques have been proposed and investigated for this purpose, and cryopreservation is a leading candidate. While tissues are cryopreserved, ice forms in both the extracellular and intracellular spaces and causes freezing-induced spatiotemporal deformation of the tissue. During this process the cells undergo dehydration by the freezing-induced osmotic pressure difference and mechanical deformation, transmitted through cell-extracellular matrix adhesions. However, the significance and interaction of these cellular level transport and mechanics processes are not well understood. Therefore, this study aims to establish mechanistic understanding …

Multi-Mode Self-Referencing Surface Plasmon Resonance Sensors, Jing Guo

Theses and Dissertations--Electrical and Computer Engineering

Surface-plasmon-resonance (SPR) sensors are widely used in biological, chemical, medical, and environmental sensing. This dissertation describes the design and development of dual-mode, self-referencing SPR sensors supporting two surface-plasmon modes (long- and short-range) which can differentiate surface binding interactions from bulk index changes at a single sensing location. Dual-mode SPR sensors have been optimized for surface limit of detection (LOD). In a wavelength interrogated optical setup, both surface plasmons are simultaneously excited at the same location and incident angle but at different wavelengths. To improve the sensor performance, a new approach to dual-mode SPR sensing is presented that offers improved differentiation …

Mass Spectrometry And Tandem Mass Spectrometry Characterization Of Protein Patterns, Protein Markers And Whole Proteomes For Pathogenic Bacteria, Jennifer Intelicato-Young

Theses and Dissertations

There have been many recent reviews published on MALDI-TOF MS (matrix assisted laser desorption/ionization time-of-flight) MS (mass spectrometry) for identification of bacteria particularly with relevance to clinical microbiology. MALDI-TOF MS is now a mature technique for bacterial identification with great promise. The purpose of this review is to put into perspective MALDI-TOF MS and other widely used mass spectrometry methods for characterization of proteins. MALDI-TOF MS is used for rapid determination of a mass pattern of proteins for bacterial characterization; these proteins

are generally not identified. Alternatively, after gel separation, MALDI TOF-TOF MSMS (tandem mass spectrometry) or on-line LC-ESI MS-MS …

Recruitment Of The Intracellular Ca2+ By Ultrashort Electric Stimuli: The Impact Of Pulse Duration, Iurii Semenov, Shu Xiao, Olga N. Pakhomova, Andrei G. Pakhomov

Bioelectrics Publications

Nanosecond-duration electric stimuli are distinguished by the ability to permeabilize intracellular membranes and recruit Ca²⁺ from intracellular stores. We quantified this effect in non-excitable cells (CHO) using ratiometric Ca²⁺ imaging with Fura-2. In a Ca²⁺-free medium, 10-, 60-, and 300-ns stimuli evoked Ca2⁺ transients by mobilization of Ca²⁺ from the endoplasmic reticulum. With 2 mM external Ca²⁺, the transients included both extra- and intracellular components. The recruitment of intracellular Ca²⁺ increased as the stimulus duration decreased. At the threshold of 200–300 nM, the transients were amplified by calcium-induced calcium release. We …

Impact Of Physical Activity In The Prevention Of Colorectal Cancer, Sarah Ashley Barnes

Theses and Dissertations

This review evaluates the current understanding of research on the impact of physical activity in the prevention of colorectal cancer. Current biological mechanisms implicated in physical activity and colorectal cancer risk reduction are blood glucose regulation, insulin sensitivity, leptin and adiponectin profiles, inflammation as well as secreted protein acidic and rich in cysteine (SPARC), an exercise induced myokine. Recent literature indicates that 30-60 minutes of moderate to vigorous activity a day is effective against colorectal cancer development, and there is convincing evidence of aerobic exercise as differently beneficial in recruiting mechanisms identified as preventative against colorectal cancer. This article provides …

The Anti-Angiogenic Effects Of Sparstolonin B, Henry Rhodes Bateman

Theses and Dissertations

Sparstolonin B (SsnB) is a novel bioreactive compound isolated from Sparganium stoloniferum, an herb historically used in Traditional Chinese Medicine as an anti-tumor agent. SsnB has demonstrated anti-inflammatory properties, inhibiting Toll-like receptor mediated inflammation in isolated macrophages and in mice. Angiogenesis, the process of new capillary formation from existing blood vessels, is dysregulated in many pathological disorders, including atherosclerosis, diabetic retinopathy, and tumor growth. The goal of the project was to investigate the anti-angiogenic effects of SsnB.

The first part of the project utilized in vitro functional assays to study how SsnB affected endothelial cells. SsnB inhibited endothelial cell tube …

Resveratrol Attenuates The Development Of Trans-Aortic Constriction (Tac) Induced Heart Failure In Mice, Prakash Kumar Gupta

Theses and Dissertations

Heart failure (HF) still remains the leading cause of morbidity and mortality and imposes severe global affliction and enormous cost on the healthcare system. Although current pharmacological therapies have shown to slow down the progression of HF, but seems to have reached their limits in improving overall patient prognosis. Thus, an immediate call for novel alternate therapies are needed which act independently as well as in conjunction with current treatment modality. Studies were performed in the well-established transverse aortic constriction (TAC) model of chronic pressure overload (PO) in mice. In the first series of studies, Male C57BL6 mice (26-28 g) …

Linking Obesity To Colorectal Cancer: Recent Insights Into Plausible Biological Mechanisms, Catherine Guffey

Theses and Dissertations

Obesity has emerged as a leading environmental risk factor for the development of CRC. However, the mechanisms underlying this relationship have not yet been fully explained. Recent literature has focused on 1) inflammatory processes, 2) adipokines, and 3) estrogen. Obesity-enhanced inflammation is largely orchestrated by increases in adipose tissue macrophages leading to the secretion of TNF-alpha, MCP-1, and IL-6, all of which are linked to CRC. Adiponectin is decreased with obesity and has been reported to be negatively associated with CRC, while leptin, which is increased, is positively associated with the disease. Estrogen has been shown to influence CRC, although …

High Fat Diet Induced Obesity In A Mouse Model For Colorectal Cancer, Kennerly Clinton Patrick

Theses and Dissertations

Obesity is widely correlated with the incidence of colorectal cancer (CRC). The exact mechanisms that link obesity to CRC risk have not yet been fully established, and only a limited number of animal models are available to study pathways involved in obesity-related colon carcinogenesis. The objective of this study was to determine the influence of HFD-induced obesity on AOM/DSS-mediated colorectal tumorigenesis, tumor proliferation, and symptom severity. Male C57BL/6 mice were fed a novel high fat diet, designed to mimic the standard American diet (12 % saturated fat & 28 % unsaturated fat), at 4 weeks of age until 16 weeks …

Osteon-Mimetic Nanocomposite Materials For Bone Regeneration, Ozan Karaman

Theses and Dissertations

The limitations of large bone defect regeneration has brought the focus of Bone Tissue Engineering research on fabricating three-dimensional bone-mimetic grafts that could enhance osteogenesis and vascularization. Osteons composed of apatite-deposited aligned collagen nanofiber layers are the fundamental building blocks of cortical bone. In natural cortical bone, mineralization is mediated by extracellular matrix (ECM) proteins with amino acid sequences rich in glutamic acid. This dissertation is focused on the establishment of a novel biomimetic approach to engineer scaffolds for healing large bone defects.

In the first part, we investigated the effect of calcium phosphate (CaP) deposition on aligned surface-modified nanofibers …

Microencapsulation Of A Connexin-43 Mimetic Peptide As A Novel Wound Healing Agent In An Ocular Injury Model, Keith Brian Moore

Theses and Dissertations

Corneal transplantation and related surgical procedures are areas of tissue replacement which have seen promising advances. Currently, cornea transplants are one of the most common surgical procedures, with approximately 40,000 occurring each year in the United States. Still, problems exist with a 20% rejection rate, post surgical infections, and the need for a constant supply of donors. The ability to safely and quickly heal and regenerate corneal epithelia fills an area of advancement in regenerative medicine, with implications reaching beyond the scope of vision therapies toward healing of a wide range of tissues and wounds. In vivo corneal wounds were …

Effect Of Physiological Oxygen Levels On Osteogenic Differentiation Of Adipose-Derived Stem Cells, Suchit Sahai

Theses and Dissertations

Regenerative medicine presents exciting strategies for healing critical-size bone defects through the implantation of cells and biocompatible scaffolds. Most in vitro studies are performed in atmospheric oxygen conditions (~20%), which do not accurately mimic the CSD microenvironment. Due to damage to the vasculature at CSDs, oxygen levels fall into the hypoxic range (<5%), which can impact viability, proliferation and differentiation of the cells employed for bone regeneration. Understanding the cellular responses to hypoxia has grown primarily from study of individual molecular factors. The master regulator of adaptive responses to low oxygen availability is the nuclear factor, hypoxia-inducible factor-1. HIF-1 is a heterodimeric protein, stable below 6% O2 condition in the nucleus and has been shown to play a role in angiogenic-osteogenic coupling. We have developed a responsive, fluorescent, hypoxia detection system and determined whether HIF activity can be tracked in both 2-D and 3-D cultures. Adipose-derived stem cells (ASCs) were selected due to their broad utilization in tissue engineering strategies and characterized the influence of HIF signaling on its phenotype. The work done identified that of hypoxia impaired osteogenic differentiation of ASCs in both 2-D and 3-D cultures and HIF-1 did not mediate this effect. Ischemic preconditioning (IPC) strategy and varied protocols used represents a clinically feasible manipulation of cell preparation to help the survival of implanted ASCs and accelerate osteogenic differentiation at physiological oxygen levels.

Characterizing Hypoxia And Its Behavioral Effects In 3-Dimensional Cell Aggregates, Matthew Lorincz Skiles

Theses and Dissertations

Cell transplantation can be considered a regenerative therapy, an intervention which attempts to replace or restore the function of compromised tissue by harnessing innate properties of cells that cannot be replicated artificially. For such therapies to succeed, it will be necessary to understand and closely match the physiological conditions that govern cell behaviors in vivo. One important factor is low oxygen tension, termed hypoxia, which is often overlooked in vitro. Because oxygen insufficiency can lead to cell death, hypoxia has traditionally been viewed as a negative condition. However, hypoxia can also serve as a potent regulator of crucial cell behaviors …

Development Of Proteomic Characterization And Speciation Techniques Utilizing Tryptic Peptides With Maldi-Tof Ms And Lc-Esi Ms-Ms, Jennifer Marie Kooken

Theses and Dissertations

The characterization of microbes which can be opportunists and pathogens (e.g., methicillin resistant Staphylococcus aureus (MRSA)) is important in understanding and potentially treating diseases caused by various bacterial species. Common genera found in the human skin micro-biome include Micrococcus and Staphylococcus, but there only a limited number of tests to differentiate these genera and/or species. My research reflects methods development from distinguishing one closely related genera from another and then expanded to species identification. Tryptic peptides were analyzed by MALDI TOF MS and the mass profiles compared with those of a reference strain in both genus and species identification. Aconitate …

Investigation Of Start Domain Proteins In Human Luteinized Cells And Cos-1 Cells, Bo Shi

Theses and Dissertations

After the luteinizing hormone surge of the menstrual cycle, the ovarian follicular granulosa and theca cells terminally differentiate to form the luteal cells of the corpus luteum. During this process known as luteinization, granulosa cells begin to synthesize large quantities of progesterone, a hormone essential for pregnancy. The rate limiting step for the de novo synthesis of pregnenolone (the precursor to progesterone) is the transport of cholesterol from the outer to the inner mitochondrial membrane, a process mediated by STARD1. STARD1 contains a C-terminal lipid binding domain holding one molecule of cholesterol, and an N-terminal domain targeting STARD1 to the …

The Effect Of Αct-1 Peptide On Bone Marrow Stromal Cells Following Injury, Adam Clay Vandergriff

Theses and Dissertations

Connexin43 (Cx43) is a component of gap junctions and is involved in intercel- lular signaling following injury to tissues. The carboxyl terminus of Cx43 binds to the PDZ2 domain of ZO-1 in order to form gap junction plaques and connect to the cytoskeleton. A biomimetic peptide known as αCT-1, replicating the last 9 amino acids found in the carboxyl terminus of CX43, has been shown to improve wound healing by preferentially binding to the PDZ2 domain of ZO-1. A possible mecha- nism for its action is through the Epithelial-Mesenchymal Transformation (EMT). Scratch assays were performed on rat bone marrow stromal …

Framework For Simulation Of Heterogeneous Mpsoc For Design Space Exploration, Bisrat Tafesse, Venkatesan Muthukumar

Electrical & Computer Engineering Faculty Research

Due to the ever-growing requirements in high performance data computation, multiprocessor systems have been proposed to solve the bottlenecks in uniprocessor systems. Developing efficient multiprocessor systems requires effective exploration of design choices like application scheduling, mapping, and architecture design. Also, fault tolerance in multiprocessors needs to be addressed. With the advent of nanometer-process technology for chip manufacturing, realization of multiprocessors on SoC (MpSoC) is an active field of research. Developing efficient low power, fault-tolerant task scheduling, and mapping techniques for MpSoCs require optimized algorithms that consider the various scenarios inherent in multiprocessor environments. Therefore there exists a need to develop …