Biomedical Engineering and Bioengineering Commons^™

A Novel Function For Fancj Helicase In Microsatellite Stabilization During Replication Stress, Joanna Barthelemy

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Noncanonical DNA structure-forming sequences, such as hairpin structures, stall replication forks in vivo, expand or contract during DNA replication, and colocalize with chromosome fragile sites. Since the frequency of hairpin formation is higher than the frequency of expansion or contraction, the cell may possess mechanisms to resolve hairpin structures prior to replication fork stalling. One possible activity for hairpin resolution is the FANCJ DNA helicase, known to unwind noncanoncial DNA structures in vitro. Indeed, mutations or loss of any of the nineteen FANC genes, including FANCJ, leads to genome instability and the cancer-prone syndrome Fanconi anemia (FA). To test whether …

Silver Nanoparticles: The Immediate Benefits Of Low Bacterial Resistance And The Long-Term Risk Of Persistent Stress In Mammalian Cells, David Harold Ellis

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Silver nanoparticles (AgNPs) are the fastest growing sector of nanotechnology, due mostly to their antibacterial properties. The antibacterial effectiveness of AgNPs is well known and derives from the shedding of silver ions which have multiple antibacterial targets in the bacterial cell. Due to their continuous release of ions and demonstrated antibacterial potency, some predict that AgNPs have a low potential for resistance development, which would make them a valuable asset in wound management. The ability for AgNPs to cause oxidative imbalance in mammalian cells is also well known, but the potential long-term impact of such a stress has not been …

Design Of A Low-Cost Wireless Nirs System With Embedded Linux And A Smartphone Interface, Diogo Da Silva Dias

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Wireless near-infrared spectroscopy (NIRS) systems can help to reduce movement artifacts, and distraction due cables. Utilizing Embedded Linux (EL) can reduce size, development time, cost of a project and allow portability. The goal of this project is to develop a low-cost wireless small-sized NIRS system using EL and a Smartphone as the interface. This was achieved using a BeagleBone Black (BBB) with a deployed custom EL that: (1) controls two sources, (2) receives data from photodetectors (PDs), (3) processes, stores and transmits data via Bluetooth to an Android Smartphone. This device was implemented in under US$150 and its dimension was …

Neural Correlates Of Convergence Eye Movements In Convergence Insufficiency Patients Vs Normal Binocular Vision Controls: An Fmri Study, Chirag Bharatkumar Limbachia

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Convergence Insufficiency is a binocular vision disorder, characterized by reduced ability of performing convergence eye movements. Absence of convergence causes, eye strain, blurred vision, doubled vision, headaches, and difficulty reading due frequent loss of place. These symptoms commonly occur during near work. The purpose of this study was to quantify neural correlates associated with convergence eye movements in convergence insufficient (CI) patients vs. normal binocular vision (NBV) controls, and to examine statistical differences between them. Functional magnetic resonance imaging (fMRI) scans were collected using a 3T Siemens scanner. A disparity-driven convergence task was designed using a standard block design approach, …

Measuring Brain Activation Through Functional Magnetic Resonance Imaging (Fmri) During Visual Task Learning, Mohd Saif Usmani

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The purpose of this study is to understand the brain activity associated with learning a visual task by utilizing the applications of functional magnetic resonance imaging in cognitive neuroscience. The study was performed using two visual tasks referred to as aircraft and control, respectively. We compared the brain activation of these two visual tasks to understand the learning process of the participants. Fifteen young adults, ten males and five females, ranging in age from 19 to 35 years, participated in a ten-week study. Eight participants dropped out either voluntarily or were excluded for different reasons. The data analysis was completed …

Biocorrosion Rate And Mechanism Of Metallic Magnesium In Model Arterial Environments, Patrick Bowen

Dissertations, Master's Theses and Master's Reports

A new paradigm in biomedical engineering calls for biologically active implants that are absorbed by the body over time. One popular application for this concept is in the engineering of endovascular stents that are delivered concurrently with balloon angioplasty. These devices enable the injured vessels to remain patent during healing, but are not needed for more than a few months after the procedure. Early studies of iron- and magnesium-based stents have concluded that magnesium is a potentially suitable base material for such a device; alloys can achieve acceptable mechanical properties and do not seem to harm the artery during degradation. …

Development Of High Capacity Hyperbranched Nitric Oxide Donors For Controlling Subcutaneous Inflammation, Sean Hopkins

Dissertations, Master's Theses and Master's Reports

Implanted medical devices undergo complications the longer they remain in contact with tissue or blood. This rejection of foreign materials by our body is one of the largest reasons innovations in biomedical sensors and implanted technology are being held back. One means to hold off this unwanted response is through the utilization of nitric oxide (NO) releasing materials. Two unique NO releasing polymeric materials were synthesized and characterized before being implanted subcutaneously. Both NO releasing materials described used S-nitrosothiol (RSNO) chemistry as the main mechanism for NO release. The first material described covalently links an RSNO to the backbone of …

Characterization Of Closed Head Impact Injury In Rat, Yi Hua, Praveen Akula, Matthew Kelso, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

The closed head impact (CHI) rat models are commonly used for studying the traumatic brain injury. The impact parameters vary considerably among different laboratories, making the comparison of research findings difficult. In this work, numerical CHI experiments were conducted to investigate the sensitivities of intracranial responses to various impact parameters (e.g., impact depth, velocity, and position; impactor diameter, material, and shape). A three-dimensional finite element rat head model with anatomical details was subjected to impact loadings. Results revealed that impact depth and impactor shape were the two leading factors affecting intracranial responses.The influence of impactor diameter was region-specific and an …

Technoeconomics And Sustainability Of Renewable Methanol And Ammonia Productions Using Wind Power-Based Hydrogen, Michael J. Matzen, Mahdi H. Alhajji, Yaşar Demirel

Yaşar Demirel Publications

This study analyzes and compares the economics and sustainability aspects of two hydrogenation processes for producing renewable methanol and ammonia by using wind-power based electrolytic hydrogen. Carbon dioxide from an ethanol plant is used for producing methanol, while the nitrogen is supplied by an Air Separation Unit (ASU) for producing ammonia. The capacities are 99.96 mt/day methanol and 1202.55 mt/day anhydrous ammonia. The methanol plant requires 138.37 mt CO₂/day and 19.08 mt H₂/day. The ammonia is synthesized by using 217.72 mt H₂/day and 1009.15 mt N₂/day. The production costs and the carbon …

Thermosensitive Gel Containing Cellulose Acetate Phthalate-Efavirenz Combination Nanoparticles For Prevention Of Hiv-1 Infection, Abhijit A. Date, Annemarie Shibata, Emily Mcmullen, Krista La Bruzzo, Patrick Bruck, Michael Belshan, You Zhou, Christopher J. Destache

Nebraska Center for Biotechnology: Faculty and Staff Publications

The objective of this investigation was to develop and evaluate a nano-microbicide containing a combination of cellulose acetate phthalate (HIV-1 entry inhibitor) and efavirenz (anti-HIV agent) for HIV prophylaxis. Cellulose acetate phthalate-efavirenz combination nanoparticles (CAP-EFV-NPs) were fabricated by the nanoprecipitation method and were characterized for particle size, zeta potential and encapsulation efficiency of efavirenz. CAP-EFV-NPs were incorporated into a thermosensitive gel (CAP-EFV-NP-Gel). CAP-EFV-NPs, CAP-EFV-NP-Gel and efavirenz solution were evaluated for cytotoxicity to HeLa cells and for in vitro short-term (1-day) and long-term (3-day) prophylaxis against HIV-1 infection in TZM-bl cells. CAP-EFV-NPs had size < 100 nm, negative surface charge and encapsulation efficiency of efavirenz was > 98%. CAP-EFV-NPs and CAP-EFV-NP-Gel were significantly less …

Design And Creation Of A Device To Induce Vergence Eye Movements, Jacob B. Jaminet, Paul A. Wetzel

Undergraduate Research Posters

Automated eye-tracking systems can detect and analyze eye movements as a means to accurately diagnose more than 20 neurological diseases including mild traumatic brain injury. Mild traumatic brain injury is an occurrence of injury to the head resulting from blunt trauma or from acceleration or deceleration forces. Eye movement refers to the voluntary or involuntary movement of the eyes, helping in acquiring, fixating and tracking visual stimuli. There are three types of voluntary eye movement to track objects: smooth pursuit, vergence shifts and saccades. Vergence shifts are eye movements where the eyes move in opposite directions: moving to the midline …

The Neuromuscular Response To Spinal Manipulation: Quantifying The Effect Of Pain With Electromyography, Stuart James Currie

Electronic Theses and Dissertations

Objective

To establish a methodology to quantify the neuromuscular response to spinal manipulation, develop a comprehensive date set including factors that affect the response, and compare the responses in both healthy participants and participants with acute and chronic low back pain.

Methods

Surface and indwelling electromyography at eight muscle locations were recorded during lumbar side-lying manipulations in 20 asymptomatic participants, 20 acute pain participants, and 20 chronic pain participants. Onset delay detection was optimized for signal detection failures and methodological comparisons were performed using a generalized linear model. The number of muscle responses and muscle activity onset delays in relation …

The Synthesis And Characterization Of Dual-Modified Carboxymethylcellulose For Bioadhesive Applications, Fabrice Bernard

Dissertations and Theses

Reparative medical techniques, in conjunction with existing and emerging tissue adherents and sealants, offer practicing physicians a wide variety of tools to improve the functionality, performance, and safety of surgical interventions. Carboxymethylcellulose (CMC) is a plant-derived polymer that is cytocompatible, biocompatible, biodegradable, and inexpensive. The need for a non-toxic but strongly adherent material motivated the development of an injectable bioadhesive system containing CMC modified with functional methacrylate and aldehyde groups that could potentially be used as an annulus fibrosus sealant or as a supplement to existing wound closure materials. After modification, the polymer was characterized via NMR spectroscopy, Schiff’s base …

Calibration And Validation Of An In Vitro Ultrasound Device To Deliver Targeted Thermal Enhancement Of Hmsc Osteogenesis, Dionne Dawkins

Dissertations and Theses

Osteoarthritis (OA) is a disease that affects millions of people annually, often the elderly, and limits their physical abilities. Current methods of treating OA are often very invasive, and expensive, costing the Medicare system billions of dollars annually. A minimally invasive therapy that can be localized to the affected area that provides both relief and a short recovery time is optimal for treating the disease. For targeted therapy and clinical use, therapeutic ultrasound in the 0.7 MHz to 3 MHz frequency range can provide relief and is convenient, portable and localized. Low-intensity pulsed ultrasound (LIPUS) has been proven in clinical …

Chemotaxis Of Central Nervous System-Derived Tumor Cells Within Controlled Microenvironments, Jennifer Rico Varela

Dissertations and Theses

Medulloblastoma (MB) is a malignant pediatric brain tumor known for its aggressive metastatic potential. Despite the well-documented migration of MB cells to other parts of the brain and spinal column, MB chemotaxis is poorly understood. Herein, we examined the in vitro migratory and cellular responses of MB-derived cells to external signaling of Epidermal Growth Factor (EGF), hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF-BB), and the stromal cell-derived factors 1-alpha (SDF-1). Experiments utilized transwell assays and immunocytochemistry to identify receptor activation in MB migration, and used a microfluidic platform to examine directionality, trajectory, and gradient- dependence of motile cells. Data …

Assessment Of Injection Behavior Of Commercially-Available Bone Bsms For Subchondroplasty Procedures, Dinely A. Colon

Dissertations and Theses

Subchondroplasty is a procedure that utilized bone substitutes materials (BSMs) or bone cement to correct bone defects in the subchondral bone. The two main materials used to compose BSMs are poly-methyl-methacrylate (PMMA) and calcium phosphate cement (CaP). Currently, there is no optimal bone material substitute in the market that can provide both the adequate mechanical support and the right viscosity to reach the affected area in the subchondral bone. In addition, there is also no established parameter for their proper use, based on the defect size and location. PMMA possesses comparable mechanical properties to bone (i.e. 96 MPa in compressive …

Monolithic Optofluidic Ring Resonator Lasers Created By Femtosecond Laser Nanofabrication, Hengky Chandrahalim, Qiushu Chen, Ali A. Said, Mark Dugan, Xudong Fan

Faculty Publications

We designed, fabricated, and characterized a monolithically integrated optofluidic ring resonator laser that is mechanically, thermally, and chemically robust. The entire device, including the ring resonator channel and sample delivery microfluidics, was created in a block of fused-silica glass using a 3-dimensional femtosecond laser writing process. The gain medium, composed of Rhodamine 6G (R6G) dissolved in quinoline, was flowed through the ring resonator. Lasing was achieved at a pump threshold of approximately 15 μJ/mm². Detailed analysis shows that the Q-factor of the optofluidic ring resonator is 3.3 × 10⁴, which is limited by both solvent …

Assessment Of Electrode Configurations Of Electrical Impedance Myography For The Evaluation Of Neuromuscular Diseases, Khondokar Mohammad Fazle Rabbi

College of Graduate Studies: Theses & Dissertations

Electrical impedance myography (EIM) is a painless, noninvasive approach to measure the neuromuscular disease status. EIM parameters- resistance (R), reactance (X) and phase (θ) depend significantly on subcutaneous fat thickness, muscle size and inter electrode distance. The objective of this research is to find an electrode configuration which can minimize the effects on EIM parameters due to subcutaneous fat thickness variation. In this study, a model of human upper arm was developed using finite element method (FEM), which has already been established as an appropriate approach for the analysis of non-symmetrical shape for assessing alternations of muscle in disease-induced changes …

Measuring The Acute Physiological Effects Of Leptin In The Carotid Body, Richard Laurence Pye

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Obesity is the healthcare crisis of our generation. Circulating levels of the adipokine leptin are proportional to adiposity and in addition to its role as a satiety factor leptin has been shown to have a host of pleiotropic effects. Among these effects is its role as a respiratory stimulant where it has been shown to have both whole body and central stimulatory effects on breathing. Porzionato et al. (2011) showed that leptin and leptin receptors are selectively expressed in the chemosensing type I cells of the carotid body. Carotid bodies are small chemosensitive organs that act as the primary peripheral …

The Guinea Pig Model For Organophosphate Toxicology And Therapeutic Development, Christopher Daniel Ruark

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Organophosphates (OPs) are highly toxic insecticides and nerve agents that have been designed to inhibit the hydrolysis of acetylcholine by binding to the serine active site of acetylcholinesterase (AChE). They are one of the most common causes of human poisoning worldwide and are frequently intentionally used in suicides in agricultural areas. For this reason, there is a need for therapeutics to rescue those from intoxication. Obvious ethical concerns prevent humans from being subjected to OP exposure for therapeutic efficacy and safety testing. Therefore, animal surrogates for humans must be appropriately selected. A new paradigm, described herein, incorporating both in silico …