Biomedical Engineering and Bioengineering Commons^™

Reactive Oxygen Modulates B Lymphocyte Function Via The Nfκb/Rel Pathway, Eric J. Romer

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Reactive Oxygen Intermediates (ROI) can significantly affect B Lymphocyte function, but the effects on key signaling pathways and gene expression in activated and non-activated B lymphocytes are largely undefined. This study demonstrates a concentration dependent effect of exogenous hydrogen peroxide on the transcriptional regulation of a 3' regulatory region of the Immunoglobulin heavy chain gene (3'IghRR). Specifically, low μM hydrogen peroxide induces an enhancing effect while higher μM hydrogen peroxide (greater than or equal to 100 μM) is suppressive. The enhancing effects of hydrogen peroxide on 3'IghRR activity are dependent on the NFκB/Rel pathway, and appear to be most prominent …

A Comprehensive Tool And Analytical Pathway For Differential Molecular Profiling And Biomarker Discovery, Claude Curtis Grigsby

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The key requirements to any empirically based study are to: (1) accurately measure and then compare the collected results in determining the result of the hypothesis being tested; and (2) collect a sample representative of the entities being studied. To demonstrate that an informatics tool can be designed that provides spectral registration, spectral and chromatographic alignment, visualization, and comparative analysis for data generated from multiple analytical platforms, e.g., LC-MS and GC-MS, the results and data analysis of five unique sets of experiments using a suite of novel informatics tools are presented. Comprehensive and reproducible sample collection techniques were developed concomitantly …

Simulating Hemodynamics In In Vitro Culture Models: Implications On Nano-Biointeractions, Monita Sharma

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Gold nanoparticles (Au-NPs) have demonstrated great potential in the development of a variety of tools with applications ranging from biomedical to military fields. Consequently, there is increasing concern regarding the toxic potential of these nanomaterials. Biodistribution studies demonstrate clearance of Au-NPs from peripheral circulation and bulk localization primarily in the liver and spleen post- intravenous administration. Deposition of Au-NPs in spleen suggests the potential for direct exposure of immune cells to these foreign materials under relatively static conditions. Although much less, due to the Blood Brain Barrier (BBB), Au-NPs appear to also deposit in the brain, suggesting that the resident …

The Molecular Genetics Learning Progressions: Revisions And Refinements Based On Empirical Testing In Three 10th Grade Classrooms, Amber Nicole Todd

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In the past few decades, there has been a large push for increasing scientific literacy (AAAS, 1989; AAAS, 1993; Achieve, 2013; NRC, 1996; NRC, 2012), especially in areas that are rapidly advancing, like molecular genetics. Much research has been done on student understandings of molecular genetics and the consensus is that the concepts are difficult both to learn and teach (Fisher, 1992; Horwitz, 1996; Kindfield, 1992; Lewis & Kattmann, 2004; Marbach-Ad & Stavy, 2000; Stewart et al., 2005; Venville & Treagust, 1998; etc.). Two learning progressions in molecular genetics have been produced (Duncan et al., 2009; Roseman et al. 2006), …

Investigation Of The Utility Of Center Frequency In Electroencephalographic Classification Of Cognitive Workload Transitions, Jones Melissa

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Successful classification of human cognitive workload is a vital component in identifying and avoiding potential performance deficits resulting from operator work overload. Previous research suggests that electroencephalogram (EEG) derived features, including center frequency, provide a robust signal which may be used to obtain highly accurate workload classification. The purpose of this work is to investigate evidence of physiological hysteresis and determine if center frequency improves a classifier's ability to correctly identify workload level. Results confirmed that including spectral data creates the most robust feature sets, while center frequency across all bands is equally reliable for classifying workload in the case …

New Insights Into The Spinal Recurrent Inhibitory Pathway Normally And After Motoneuron Regeneration, Ahmed Zayed Obeidat

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Despite more than seven decades of intensive research, uncertainty is the hallmark of spinal recurrent inhibition. The simplest possible structure that is formed between the a-motoneuron and its inhibitory interneurons has been the subject of long lasting scientific debate. To date, there is no consensus on the functional significance of this circuit. Even the simplest assumption of a negative feedback loop does not hold true. The current work used the technique of in vivo intracellular recording from the adult rat a-motoneurons to study the normal function and the plasticity after nerve injury and regeneration of this simple, yet intricate spinal …

Utility Of A Volume-Regulated Drive System For Direct Mechanical Ventricular Actuation, Benjamin A. Schmitt

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Direct Mechanical Ventricular Actuation (DMVA) is a non-blood contacting cardiac assist device that augments ventricular function. The purpose of this study was to determine if a volume-regulated "hand pump" drive system and a pressure-regulated "switch tank" drive system provide equivalent levels of cardiac support. Canine (n=2) and swine (n=4) were instrumented for hemodynamic monitoring and intravascular echocardiography. DMVA support was assessed during both severe heart failure and fibrillation. Pump function was evaluated using hemodynamic measures to calculate stroke work. Myocardial function was assessed using echocardiographic speckle tracking to quantify strain rate. Results were compared between groups using paired t-tests. There …

Bacillus Thuringiensis: Transgenic Crops, Julie A. Peterson, John J. Obrycki, James D. Harwood

Department of Entomology: Faculty Publications

Bacillus thuringiensis (Bt) crops, genetically modified to express insecticidal toxins that target key pests of corn, cotton, rice, potato, and other crops, have been rapidly adopted and have become dominant fixtures in agroecosystems throughout the world. Due to the constitutive nature of Bt toxin expression, insecticidal proteins may be found in nearly all plant tissues, presenting multiple sources for Bt toxins to enter the environment, thus creating complex direct and indirect pathways for non-target organisms to be exposed to insecticidal proteins. The environmental impacts of Bt crops have been widely debated, although both benefits and risks do exist. Benefits of …

Evaluation Of Endogenous Allergens For The Safety Evaluation Of Genetically Engineered Food Crops: Review Of Potential Risks, Test Methods, Examples And Relevance, Richard E. Goodman, Rakhi Panda, Harsha Ariyarathna

Department of Food Science and Technology: Faculty Publications

The safety of food produced from genetically engineered (GE) crops is assessed for potential risks of food allergy on the basis of an international consensus guideline outlined by the Codex Alimentarius Commission (2003). The assessment focuses on evaluation of the potential allergenicity of the newly expressed protein(s) as the primary potential risk using a process that markedly limits risks to allergic consumers. However, Codex also recommended evaluating a second concern, potential increases in endogenous allergens of commonly allergenic food crops that might occur due to insertion of the gene. Unfortunately, potential risks and natural variation of endogenous allergens in non-GE …

Surface- And Hydrogel-Mediated Delivery Of Nucleic Acid Nanoparticles, Angela K. Pannier, Tatiana Segura

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Gene expression within a cell population can be directly altered through gene delivery approaches. Traditionally for nonviral delivery, plasmids or siRNA molecules, encoding or targeting the gene of interest, are packaged within nanoparticles. These nanoparticles are then delivered to the media surrounding cells seeded onto tissue culture plastic; this technique is termed bolus delivery. Although bolus delivery is widely utilized to screen for efficient delivery vehicles and to study gene function in vitro, this delivery strategy may not result in efficient gene transfer for all cell types or may not identify those delivery vehicles that will be efficient in vivo. …

Bile-Acid-Mediated Decrease In Endoplasmic Reticulum Stress: A Potential Contributor To The Metabolic Benefits Of Ileal Interposition Surgery In Ucd-T2dm Rats, Bethany P. Cummings, Ahmed Bettaieb, James L. Graham, Jaehyoung Kim, Fangrui Ma, Noreene Shibata, Kimber L. Stanhope, Cecilia Giulivi, Frederik Hansen, Jacob Jelsing, Niels Vrang, Mark Kowala, Michael L. Chouinard, Fawaz G. Haj, Peter J. Havel

Nebraska Center for Biotechnology: Faculty and Staff Publications

Post-operative increases in circulating bile acids have been suggested to contribute to the metabolic benefits of bariatric surgery; however, their mechanistic contributions remain undefined. We have previously reported that ileal interposition (IT) surgery delays the onset of type 2 diabetes in UCD-T2DM rats and increases circulating bile acids, independently of effects on energy intake or body weight. Therefore, we investigated potential mechanisms by which post-operative increases in circulating bile acids improve glucose homeostasis after IT surgery. IT, sham or no surgery was performed on 2-month-old weight-matched male UCD-T2DM rats. Animals underwent an oral fat tolerance test (OFTT) and serial oral …

Biomechanical Comparison Of Lower Limb Unloading Between Common Modalities Of Ankle Foot Orthoses, Andrea Blake Wanamaker

Electronic Theses and Dissertations

Tibial stress fractures and other lower extremity injuries can be treated using an ankle foot orthosis (AFO). AFOs are popular because they allow the patient to ambulate somewhat naturally while reducing weight bearing on the injured limb. Despite their popularity, it is currently unclear how well AFOs reduce lower extremity weight bearing.

The first objective of this investigation was to examine the ability of three commonly used ankle foot orthoses to reduce weight bearing within the lower limb by comparing the ground reaction force measured from a force platform to the force measured from an insole pressure measurement device inside …

Computational Representation Of The Patellofemoral Joint, Abraham Wright

Electronic Theses and Dissertations

Many people suffer from knee pain due to abnormal function of the patellofemoral joint and are not able to enjoy normal activities of daily living. Surgical treatments are available and new methods are being developed by the medical industry. However, computational tools to efficiently evaluate the effects of the intervention on patellofemoral function are lacking.

Therefore, a validated and efficient computational model of the patellofemoral joint was developed. The subject specific finite element model was validated against the patellar kinematics recorded during cadaveric patellofemoral laxity experiments of the natural knee. The development involved a sequential process in which the soft-tissue …

Representing Intersubject Variability With A Statistical Shape And Alignment Model Of The Knee, Chandreshwar Rao

Electronic Theses and Dissertations

Prior statistical shape models have not considered multiple structures in the knee joint to characterize anatomic variation which are required to investigate joint mechanics further for the successful knee replacement. Accordingly, the study's objective was to develop statistical shape and alignment model (SSAM) to capture intersubject variability and demonstrate the ability to generate realistic instances for use in finite element analysis (FEA). SSAM described the variability in the training set of 20 subjects with a series of modes of variation obtained by performing principal component analysis (PCA). PCA produced modes of variation with the first 3 modes representing 70% and …

Effect Of Rolling On Viscoelastic Fluids Using A Novel Testing Device, Aswini Mangadu

Dissertations and Theses

The purpose of this research thesis project was to develop a mechanical testing device that could enable us to load articular cartilage with a rolling/sliding motion. This novel device was then used to observe the effect of a rolling motion on the fluid film thickness of different lubricants (motor oil, synovial fluid and Hyaluronic Acid (HA)) to varying loads (1kg, 2,kg, 3kg and 4kg) and speeds (10, 25, 48 and 91 mm/s) applied on the sample fluids for 10 cycles. We were able to examine the effect of different speeds within each load for each of the fluid that was …

A Novel Visual Stimulation Paradigm: Exploiting Individual Primary Visual Cortex Geometry To Boost Steady State Visual Evoked Potentials (Ssvep), Marta Isabel Vanegas Arroyave

Dissertations and Theses

The steady-state visual evoked potential (SSVEP) is an electroencephalographic response to flickering stimuli generated in significant part by activity in primary visual cortex (V1). SSVEP signal-to-noise ratio is generally low for stimuli that are located in the visual periphery, at frequencies higher than 20 Hz, or at low contrast. Because of the typical "cruciform" geometry of V1, large stimuli tend to excite neighboring cortical regions of opposite orientation, likely resulting in electric field cancellation. In Study 1, we explored ways to exploit V1 geometry in order to boost scalp SSVEP amplitude via oscillatory summation, by manipulating flicker-phase offsets among angular …

Design, Product Development And Risk Assessment Of Tin (Sn) Ring Electrodes As A Substitute To Silver-Silver Chloride (Ag Agci) Ring Electrodes For High Definition Transcranial Direct Current Stimulation (Hd-Tdcs), Linford Leitch

Dissertations and Theses

The objective of this research thesis is to test the viability of Tin (Sn) ring electrodes as an inexpensive alternative to sintered Silver-Silver Chloride (Ag|AgCl) ring electrodes for High Definition – transcranial Direct Current Stimulation (HD-tDCS). Throughout our initial bench top testing of tin electrodes in combination with a ‘conductive electrode gel’, the passing of a 2mA direct current on agar block showed the formation of white cloud around the anode electrode and a cluster of air bubbles on the cathode. The analysis of pertinent literature indicates that the white milky substance produced during the stimulation at the anode is …

Finite Element Study Of Transcranial Direct Current Stimulation: Customization Of Models And Montages, Dennis Q. Truong

Dissertations and Theses

Transcranial Direct Current Stimulation (tDCS) is a non-invasive neuromodulation technique that applies low amplitude current via electrodes placed on the scalp. Rather than directly eliciting a neuronal response, tDCS is believed to modulate excitability – encouraging or suppressing activity in regions of the brain depending on the polarity of stimulation. The particular application of tDCS is often determined by the electrode configuration and intensity of stimulation. MRI-derived finite element models have been developed to analyze the effect of these parameters allowing novel electrode configurations to be tested in subject specific models. By creating a subject specific model of an obese …

Application Of Computational Fluid Dynamics As A Simulation-Based Design Guide In A Microfluidic 3d Living Cell Array (3d Lca) Device, A.H. Rezwanuddin Ahmed

Dissertations and Theses

The use of computational fluid dynamics (CFD) as a tool in the aerodynamics and oil industry provides a reinforcement to efficiency in the design of aircrafts or for understanding the flow through pipes. A similar approach can be taken towards microfluidics, where traditionally devices have been designed based on experience or physiological replication, and a CFD simulation is shown post-manufacture to show the flow and diffusion patterns present. In this study, a reverse approach is suggested, by designing the device first in CFD and perform simulations on variations of alterable parameters to get insight on how the changing parameters affect …

Transport Pathway Across Hcaecs Uncer Convective Condtitions And The Role Of Apoptosis In Ldl Transport Through Hcaecs, Janpen Phupeerasupong

Dissertations and Theses

No abstract provided.