Biomedical Engineering and Bioengineering Commons^™

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

Browse all Theses and Dissertations

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 …

Reducing Radiation Dose To The Female Breast During Conventional And Dedicated Breast Computed Tomography, Franco Rupcich

Dissertations (1934 -)

The purpose of this study was to quantify the effectiveness of techniques intended to reduce dose to the breast during CT coronary angiography (CTCA) scans with respect to task-based image quality, and to evaluate the effectiveness of optimal energy weighting in improving contrast-to-noise ratio (CNR), and thus the potential for reducing breast dose, during energy-resolved dedicated breast CT.

A database quantifying organ dose for several radiosensitive organs irradiated during CTCA, including the breast, was generated using Monte Carlo simulations. This database facilitates estimation of organ-specific dose deposited during CTCA protocols using arbitrary x-ray spectra or tube-current modulation schemes without the …

Diffusion Tensor Imaging Of The Central Nervous System Following An Injury To The Spinal Cord And Cell Transplant, Michael Jirjis

Dissertations (1934 -)

The purpose of this dissertation research was to characterize the use of magnetic resonance diffusion tensor imaging (DTI) as a diagnostic and prognostic tool in understanding the changes that occur throughout the spinal cord and brain following a spinal cord injury (SCI) and following stem cell transplant. The diffusion of water inside the nervous system is dramatically altered around the lesion site following a traumatic SCI. However, following damage to the spinal cord, little is known about the diffusion characteristics away from an injury and even less is understood about DTI's sensitivity to structural changes that occur following regenerative transplant …

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 …

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 …

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 …

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 …

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.

Design, Implementation, And Performance Study Of An Open Source Eye-Control System To Pilot A Parrot Ar.Drone Quadrocopter, John M. Ettikkalayil

Dissertations and Theses

Natural user interface is a fairly new concept in the field of human-computer interaction. It is the idea of using every day natural human behaviors and actions to control a device. An example of a natural user interface is touch control technology in smartphones, tablets, and new laptops. The interaction is more direct when compared to artificial input devices like a keyboard and mouse. Though natural user interface devices might not perform as well as standard input devices for certain applications, for other applications they are now the de facto standard. A new user interface that is poised to be …

Rational Reprogramming Of Fungal Polyketide First Ring Cyclization, Yuquan Xu, Tong Zhou, Zhengfu Zhou, Shiyou Su, Sue A. Roberts, William R. Montfort, Jia Zeng, Ming Chen, Wei Zhang, Min Lin, Jixun Zhan, Istvan Molnar

Biological Engineering Faculty Publications

Resorcylic acid lactones (RAL) and dihydroxyphenylacetic acid lactones (DAL) represent important pharmacophores with heat shock response and immune system modulatory activities. The biosynthesis of these fungal polyketides involves a pair of collaborating iterative polyketide synthases (iPKSs): a highly reducing iPKS (hrPKS) whose product is further elaborated by a nonreducing iPKS (nrPKS) to yield a 1,3-benzenediol moiety bridged by a macrolactone. Biosynthesis of unreduced polyketides requires the sequestration and programmed cyclization of highly reactive poly-β-ketoacyl intermediates to channel these uncommitted, pluripotent substrates towards defined subsets of the polyketide structural space. Catalyzed by product template (PT) domains of the fungal nrPKSs and …

Design And Application Of An In Vivo Reporter Assay For Phenylalanine Ammonialyase, S. Wang, S. Zhang, T. Zhou, J. Zeng, Jixun Zhan

Biological Engineering Faculty Publications

Phenylalanine ammonia-lyase (PAL) is an important enzyme that links primary metabolism to secondary metabolism. Its efficiency is often a critical factor that affects the overall flux of a related metabolic pathway, the titer of the final products, and the efficacy of PAL-based therapies. Thus, PAL is a common target for metabolic engineering and it is of significant interest to screen efficient PALs for industrial and medical applications. In this study, a novel and efficient visible reporter assay for screening of PAL efficiency in Escherichia coli was established based on a plant type III polyketide biosynthetic pathway. The candidate PALs were …

Applications Of Antioxidant And Anti-Inflammatory Polymers To Inhibit Injury And Disease, David B. Cochran

Theses and Dissertations--Chemical and Materials Engineering

There is an undeniable link between oxidative stress, inflammation, and disease. Currently, approaches using antioxidant therapies have been largely unsuccessful due to poor delivery and bioavailability. Responding to these limitations, we have developed classes of polymer and delivery systems that can overcome the challenges of antioxidant and anti-inflammatory therapy. In our initial studies, nanoparticles of poly(trolox), a polymeric form of trolox, were surface-modified with antibodies. This modification allows for specific targeting to endothelial cells, affording controllable and localized protection against oxidative stress. We have shown these targeted nanoparticles bind, internalize, and provide protection against oxidative stress generation and cytotoxicity from …

Mechanical Properties Of Human Amniotic Fluid Stem Cells Using Nanoindentation, Ashkan Aryaei, Ambalangodage Jayasuriya

Faculty Publications

The aim of this study was to obtain nanomechanical properties of living cells focusing on human amniotic fluid stem (hAFS) cell using nanoindentation techniques. We modified the conventional method of atomic force microscopy (AFM) in aqueous environment for cell imaging and indentation to avoid inherent difficulties. Moreover, we determined the elastic modulus of murine osteoblast (OB6) cells and hAFS cells at the nucleus and cytoskeleton using force–displacement curves and Hertz theory. Since OB6 cell line has been widely used, it was selected to validate and compare the obtained results with the previous research studies. As a result, we were able …

Mechanics Of Hip Dysplasia Reduction In Infants Using The Pavlik Harness: A Physics Based Computational Model, Orlando Ardila, Eduardo Divo, Faissal Moslehy, George Rab, Alain Kassab, Charles Price

Mechanical Engineering - Daytona Beach

Biomechanical factors influencing the reduction of dislocated hips with the Pavlik harness in patients of Developmental Dysplasia of the Hip (DDH) were studied using a three-dimensional computer model simulating hip reduction dynamics in (1) subluxated and (2) fully dislocated hip joints. Five hip adductor muscles were identified as key mediators of DDH prognosis, and the non-dimensional force contribution of each in the direction necessary to achieve concentric hip reductions was determined. Results point to the adductor muscles as mediators of subluxated hip reductions, as their mechanical action is a function of the degree of hip dislocation. For subluxated hips in …

Novel Device For Continuous Spatial Control And Temporal Delivery Of Nitric Oxide For In Vitro Cell Culture, Genevieve E. Romanowicz, Weilue He, Matthew Nielsen, Megan C. Frost

Michigan Tech Publications, Part 1

Nitric oxide (NO) is an ubiquitous signaling molecule of intense interest in many physiological processes. Nitric oxide is a highly reactive free radical gas that is difficult to deliver with precise control over the level and timing that cells actually experience. We describe and characterize a device that allows tunable fluxes and patterns of NO to be generated across the surface upon which cells are cultured. The system is based on a quartz microscope slide that allows for controlled light levels to be applied to a previously described photosensitive NO-releasing polydimethylsiloxane (PDMS). Cells are cultured in separate wells that are …

White Matter Structural Connectivity Is Associated With Sensorimotor Function In Stroke Survivors, Benjamin Kalinosky, Sheila M. Schindler-Ivens, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

Purpose

Diffusion tensor imaging (DTI) provides functionally relevant information about white matter structure. Local anatomical connectivity information combined with fractional anisotropy (FA) and mean diffusivity (MD) may predict functional outcomes in stroke survivors. Imaging methods for predicting functional outcomes in stroke survivors are not well established. This work uses DTI to objectively assess the effects of a stroke lesion on white matter structure and sensorimotor function.

Methods

A voxel-based approach is introduced to assess a stroke lesion's global impact on motor function. Anatomical T1-weighted and diffusion tensor images of the brain were acquired for nineteen subjects (10 post-stroke and 9 …

Finite Element Analysis Of Balloon-Expandable Coronary Stent Deployment: Influence Of Angioplasty Balloon Configuration, David Martin, Fergal Boyle

Articles

Today, the majority of coronary stents are balloon-expandable and are deployed using a balloon-tipped catheter. To improve deliverability, the membrane of the angioplasty balloon is typically folded about the catheter in a pleated configuration. As such, the deployment of the angioplasty balloon is governed by the material properties of the balloon membrane, its folded configuration and its attachment to the catheter. Despite this observation, however, an optimum strategy for modelling the configuration of the angioplasty balloon in finite element studies of coronary stent deployment has not been identified, and idealised models of the angioplasty balloon are commonly employed in the …

Automatic Detection Of Polypoid Skin Lesions: The Squash Sign, Saurabh G. Karnik

Masters Theses

“Earlier detection of malignant melanoma can save lives. Automatic in-vivo methods of melanoma detection including smart-phone applications are now available, but specificity is low, i.e. too many benign lesions are detected as possible melanomas. Polypoids, elevated and rounded lesions are one class of benign lesions. These raised lesions with piecewise circular borders, predominantly intradermal nevi and cutaneous polyps (IDNs), are always benign. Variegated coloring present in polypoid lesions can lead physicians to perform an unneeded biopsy. Contact dermatoscope plates with gel squash these lesions, leaving a “squash sign” marker of benignancy which can be automatically detected. We present a method …

An Investigation Of The Biochemical Properties Of Tetrazines As Potential Coating Additives, Swarna Jaiswal, Brendan Duffy, Luke O'Neill, Patrick Mchale

Articles

1,2,4,5-Tetrazine and its 3,6-disubstituted derivatives are currently used for a range of industrial and medical applications as they exhibit particular coordination chemistries, characterized by electron and charge transfer phenomena. The aim of the present work is to describe the synthesis of two tetrazine derivatives, namely 3,6-dihydrazino-1,2,4,5-tetrazine (DHDTZ) and 1,2,4,5-tetrazine dicarboxylic acid (DCTZ), and determine their antibacterial, antioxidant and anticorrosion characteristics as additives in a sol-gel coating on SS316L steel. The structure of the tetrazines was confirmed by NMR and FTIR while the surface morphology of bacterial cells in their presence was observed by AFM. Their ability to inhibit corrosion on …