Biomedical Engineering and Bioengineering Commons^™

The Organization Of Kv2.1 Channel Proteins In The Membrane Of Spinal Motoneurons: Regulation By Injury And Cellular Activity, Shannon Hunt Romer

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The intrinsic membrane properties of neurons in the central nervous system are controlled by the tight regulation of membrane-bound ion channels. Rather than existing as static entities operating only in opened or closed states in fixed locations, ion channels are dynamic molecules with the capacity to adopt multiple functional states through conformational changes and/or post-translational modification - enabling flexibility in their activity. Furthermore, the location of ion channels within certain membrane compartments and/or signaling ensembles is critical to synaptic integration and shaping of firing properties, and can also be dynamically modified by changes in neuronal activity and pathology. In mammalian …

An Improved Adaptive Filtering Approach For Removing Artifact From The Electroencephalogram, Justin Ronald Estepp

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The biophysics of volume conduction that enable electrophysiological data acquisition also result in the mixing of data sources including possible, undesirable noise sources at the electrode interface. This work specifically focuses on improving the performance of the recursive least-squares (RLS) adaptive filtering method for removing eye movement artifact from the electroencephalogram. In biophysically-inspired simulated data, the RLS algorithm is verified to produce results that are inferior to extended infomax independent component analysis (ICA), the most widely used artifact correction approach in this problem space, due to its non-linear filter phase response and the presence of bidirectional contamination, or cross-talk, resultant …

Regulation Of Motoneuron Firing Properties: Intrinsic And Circuit-Based Mechanisms, Adam S. Deardorff

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Body and limb movements are controlled by regulating the activity of motor pools and their constituent motoneurons. An extensive complement of tightly regulated ion channels and second messenger systems determine active motoneuron spiking behavior, while segmental propriospinal circuits ensure the faithful execution of motor commands by providing real time sensory feedback to motoneurons and other somatosensory centers. However, current mechanistic understanding is incomplete for critical factor regulating motoneuron firing properties. Fundamental gaps in knowledge exist regarding (a) the spatial distribution and organization of specific ion channels in motoneurons, (b) the contribution of specific channels to motoneuron intrinsic properties, (c) the …

Evaluating Warehouse Strategies For Two-Product Class Distribution Planning, Bradley R. Guthrie

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Distribution networks often manage products with varying life-cycles, where demand for some products is relatively stable throughout the year (basic products) and the demand for others is short-lived (fashion products). Beyond the coordination of inventory and transportation decisions, decisions at the warehouse must be considered as its resources are frequently shared by both product classes simultaneously. For this two-product class distribution planning problem, we focus on characterizing three real-world distribution strategies observed in industry and evaluating them based on total distribution cost and warehouse measures (e.g., workforce plan and workload variation) against a benchmark ILS-based heuristic. Experimental results suggest that …

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 …

The Regulation Of The Eight-Exon Isoform Of The Coxsackievirus And Adenovirus Receptor (CarEx8) And Its Biological Relevance, Poornima Kotha Lakshmi Narayan

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The airway epithelium poses a formidable barrier for the entry of pathogenic viruses due to the formation of tight junctions between adjacent epithelial cells. The coxsackievirus and adenovirus receptor (CAR), a member of the Ig superfamily of cell junction adhesion proteins, is the primary receptor for adenovirus entry and infection. As a result of alternative splicing, two transmembrane isoforms of CAR are generated. While the seven-exon isoform of CAR (CAR^EX7) is hidden on the basolateral surface of polarized epithelia, the eight-exon isoform of CAR (CAR^EX8) localizes within the sub-apical region and at the air-exposed apical surface. …

Chemosensitive Neurons Of The Locus Coeruleus And The Nucleus Tractus Solitarius: Three Dimensional Morphology And Association With The Vasculature, Cathy D. Graham

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We studied the 3 dimensional structure of LC and cNTS neurons from neonatal rats. Neurons were identified as either chemosensitive or nonchemosensitive based on their firing rate response to hypercapnia, using whole-cell patch clamping and were passively loaded with Lucifer Yellow. The identified, loaded neurons were reconstructed and analyzed using Neurolucida Neuron Tracing Software. Chemosensitive LC neurons have less rounded soma than nonchemosensitive neurons, and they have dendrites arising from two poles to produce a fusiform appearance. The dendritic branches extend a greater distance from the soma of chemosensitive than nonchemosensitive neurons. Conversely, chemosensitive cNTS neurons were found to have …

Guanine Nucleotide Exchange Activity Of Phospholipase D2 And Its Regulation, Madhupriya Mahankali

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Phospholipase D2 (PLD2) is a cell membrane lipase that catalyzes the break down of phosphatidyl choline (PC) to phosphatidic acid (PA) and choline. PA is one of the major lipid second messengers that modulate a wide variety of signaling pathways, which are crucial for various cellular functions. In addition to this, PLD2 via binding to a large number of proteins and thereby regulates them independent of its lipase activity. Whereas PLD2 is involved in plethora of cellular functions, high levels of protein and/or activity of PLD2 are reported in variety of disease conditions, such as cancer metastasis and chronic inflammation …

Apelin Regulation Of K-Cl Cotransport In Vascular Smooth Muscle Cells., Neelima Sharma

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Atherosclerosis and high circulating levels of oxidized low density lipoproteins (oxLDL) are considered among the most important risk factors for the occurrence and development of cardiovascular disease (CVD). During the atherosclerotic lesion repair, phenotypic transition of vascular smooth muscle cells (VSMCs) from contractile to synthetic states plays a central role. In this process, enhanced proliferation/migration of VSMCs, from the tunica media to the intima, is required to sustain blood vessel endothelium integrity, and for inducing vessel wall remodeling in response to injury. At the molecular level, the activity of electroneutral potassium-chloride cotransporters or KCCs, is necessary to: a) allow changes …

Evaluation Of Functional Near Infrared Spectroscopy (Fnirs) For Assessment Of The Visual And Motor Cortices In Adults, Brenna Giacherio

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Introduction: Functional near-infrared spectroscopy (fNIRS) is a relatively young technique in the field of medical imaging. As such, it has yet to be widely implemented for clinical use, despite its promising advantages. However, unlike fMRI-its much bulkier and costly counterpart-fNIRS has yet to be proven as a standalone imaging tool within a clinical setting, particularly that of ophthalmology or physical therapy.

Methods: Ten healthy young adults (23.8 ± 4.8 years) participated in the study. Activation of the visual cortex was achieved utilizing various reversing checkerboard stimuli across three data collection sessions for each participant. Further, activation of the motor cortex …

Rab3a As A Modulator Of Homeostatic Synaptic Plasticity, Andrew G. Koesters

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The nervous system is faced with perturbations in activity levels throughout development and in disease or injury states. Neurons need to adapt to these changes in activity, but also need to maintain circuit firing within a normal range to stabilize the network from becoming too excited or too depressed. Homeostatic synaptic plasticity, the compensatory increase or decrease in synaptic strength as a result of excessive circuit inhibition or excitation, is a mechanism that the nervous system utilizes to keep network activity at normal levels. Despite intense effort, little is known about the mechanisms underlying homeostatic synaptic plasticity. Numerous studies have …

Segmentation And Analysis Of Mris Of Infants With Dysphagia, Irfaan A. Dar

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Neonates are at a rapid stage of development from birth throughout childhood. Impairments to certain cortical areas can result in long lasting neuro-cognitive dysfunctions. Disorders to the swallowing neural pathways can have detrimental effects throughout life course since methods to provide nutrition can be comprised. Dysphagia, or the inability to swallow, can be caused by a multitude of reasons, chiefly neurological, but the underlying disruptions to the neural pathways are not defined. In this study we investigated the growth of multiple cortical areas involved in the swallowing pathway and categorized feeding outcomes with neural growth. Results showed that infants that …

Finite Element Simulation Of Skull Fracture Evoked By Fall Injuries, Anthony Vicini

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This study presents novel predictive equations for von Mises stresses and deflection of bones in the frontal and lateral regions of the skull. The equations were developed based on results of a finite element model developed here. The model was validated for frontal and lateral loading conditions with input values mimetic to fall scenarios. Using neural network processing of the information derived from the model achieved R2 values of 0.9990 for both the stress and deflection. Based on the outcome of the fall victims, a threshold von Mises stress of 40.9 to 46.6 MPa was found to indicate skull fracture …

The Role Of Subunit Iii In The Functional And Structural Regulation Of Cytochrome C Oxidase In Rhodobacter Spheroids, Khadijeh Salim Alnajjar

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Cytochrome c oxidase (COX) catalyzes the oxidation of ferrocytochrome c and the reduction of oxygen to water while concomitantly translocating protons across the inner mitochondrial membrane. The catalytic core of COX consists of three subunits that are conserved from the bacterial to the mitochondrial forms of the enzyme. Subunits I and II (SUI and SUII) contain the metal centers where electrons are transferred and oxygen binds for reduction. Subunit III (SUIII) does not contain any metals and has an unknown function. It contains three conserved histidine residues (3, 7 and 10) that are surface exposed and are in close proximity …

Peroxisome Proliferator-Activated Receptor Alpha: Insight Into The Structure, Function And Energy Homeostasis, Dhawal P. Oswal

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Peroxisome proliferator-activated receptor alpha (PPAR alpha) belongs to the family of ligand-activated nuclear transcription factors and serves as a lipid sensor to regulate nutrient metabolism and energy homeostasis. The transcriptional activity of PPAR alpha is thought to be regulated by the binding of exogenous ligands (example, fenofibrate, TriCor), as well as endogenous ligands including fatty acids and their derivatives. Although long-chain fatty acids (LCFA) and their thioesters (long-chain fatty acyl-CoA; LCFA-CoA) have been shown to activate PPAR alpha of several species, the true identity of high-affinity endogenous ligands for human PPAR alpha (hPPAR alpha) has been more elusive. This two …

An Investigation Of Thermal Imaging To Detect Physiological Indicators Of Stress In Humans, Carl Brady Cross

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Real-time, stand-off sensing of humans to detect emotional state would be valuable in many defense, security and medical scenarios. Using a multimodal sensor platform that incorporates high-resolution visible-wavelength and mid-wave infrared cameras and a millimeter-wave (mmW) radar system, the detection of physiological indicators of psychological stress is tested through laboratory experiments. Our approach focuses on thermal imaging to measure temperature patterns in distinct facial regions representative of underlying hemodynamic patterns. Experiments were designed to: 1) determine the ability of thermal imaging to detect high levels of psychological stress and assess responses to physical versus psychological stressors; 2) evaluate the fidelity …

Mobile Computing For Trauma And Surgical Care Continuous Education, Muhammad Y. Alamoud

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In medical domain, mobile computing has proven to be convenient, effective, and productive. With varying screen sizes, there is a challenge to present the right information in the right format such that medical practitioners can access information quickly. In this thesis, we discuss how mobile computing can be used as a way of continuous education for medical practitioners in the field of trauma and surgical care, and provide design guidelines on how to effectively present information on different mobile form factors. The focus is on three screen sizes- 4.7, 7 and 10.1 in., and three interaction methods - dropdown, slide, …

Elucidating A Role Of Btf And Trap150 In Pre-Mrna Processing And Cell Cycle Progression, Sapna N. Varia

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Transcription of protein-coding genes is coordinated with pre-mRNA processing as well as mRNP assembly and nuclear export in mammalian cells. In this dissertation, I examined the functions of two homologous non-classical serine-arginine-rich (SR) proteins, Btf (BCLAF1) and TRAP150 in these steps of gene regulation. Since Btf and TRAP150 share 39% sequence identity and 66% sequence similarity, I also examined whether Btf and TRAP150 have overlapping or distinct functions in pre-mRNA processing. Using two different reporter loci, I showed in-situ recruitment of Btf and TRAP150 at reporter transcription sites, and I identified both Btf and TRAP150 being associated with a core …

Differential Regulation Of The Hippocampal Taurine Transporter Protein In Rat Brain: Mechanisms Contributing To Neuronal Volume Regulation, Amanda Noelle Freeman

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Background. In osmotic edema, net efflux of taurine from neurons and accumulation by astrocytes contributes to neuronal volume regulation and astrocytic swelling. Taurine is accumulated in both cell types by a sodium- and chloride-dependent 72-75 kDa protein transporter, TauT. TauT functional activity decreases in osmotically swollen neurons but is unaltered in swollen astrocytes, in vitro. This swelling-induced downregulation of neuronal TauT activity is blocked with the tyrosine kinase (TK) inhibitor, genistein. In contrast, PKC activation has no effect on neuronal TauT, but inhibits astrocytic TauT. Thus, we hypothesize that during osmotic swelling, neuronal TauT activity is regulated by a TK …

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 …