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Tissue Engineering Scaffold Fabrication And Processing Techniques To Improve Cellular Infiltration, Casey Grey

Theses and Dissertations

Electrospinning is a technique used to generate scaffolds composed of nano- to micron-sized fibers for use in tissue engineering. This technology possesses several key weaknesses that prevent it from adoption into the clinical treatment regime. One major weakness is the lack of porosity exhibited in most electrospun scaffolds, preventing cellular infiltration and thus hosts tissue integration. Another weakness seen in the field is the inability to physically cut electrospun scaffolds in the frontal plane for subsequent microscopic analysis (current electrospun scaffold analysis is limited to sectioning in the cross-sectional plane). Given this it becomes extremely difficult to associate spatial scaffold …

Study On The Vortex Wake Of An Airfoil Equipped With Flexible Trailing Edge Fringes, Zhengkai He

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With the inspiration of owl's silent flight, a traditional airfoil S833 equipped with flexible fringes on the trailing edge is investigated through numerical simulation and experiments in a wind tunnel. The newly constructed airfoil is modeled and numerically investigated. An incompressible, 2D and viscous flow solver in the Computational Fluid Dynamics (CFD) software FLUENT is utilized to conduct the numerical simulation on the vortex flow feature in the wake of the airfoil. A User Defined Function code was applied to generate the defined motion of flexible fringes. The effects of the flapping frequency of the fringe and the deformation pattern …

Hierarchical Porous Structures Functionalized With Silver Nanoparticles: Adaptation For Antibacterial Applications, Anil Kumar Karumuri

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For a large number of applications involving surface interactions, there is an ever growing demand for materials with high specific surface area (surface area to volume ratio). Porous materials and nanomaterials offer higher specific surface area (SSA) each with their respective advantages and disadvantages. This research program is focused on bringing the two approaches together to create truly "hierarchical" materials that combine advantages of both while minimizing their disadvantages. In this study, various carbon based porous geometries were fabricated by grafting carbon nanotubes (CNT) onto highly porous reticulated carbon foams. These structures were further modified by functionalizing metal nanoparticles such …

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 …

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 …

Use Of Vibrotactile Feedback And Stochastic Resonance For Improving Laparoscopic Surgery Performance, Robert Douglas Hoskins

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Vibrotactile feedback, used as sensory substitution for loss of haptic feedback, has been utilized to improve performance in manual control, teleoperation and during minimally invasive surgical tasks. Stochastic resonance (SR), introduced into the human control system as white noise at a sub-threshold level, has shown promise to improve the sensitivity of tactile receptors resulting in enhancement of performance for a variety of manual tracking and sensorimotor tasks. The purpose of this study was to determine if SR could improve performance (accuracy, speed) in a simulated laparoscopic palpation task and to compare it to vibrotactile feedback (VIB). It was hypothesized that …

Design Of Thermal Structures Using Topology Optimization, Joshua D. Deaton

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The design of structures subjected to elevated temperature environments has long been an important area of study in the aerospace industry. This is especially true in the modern day, where new problems related to embedded engine aircraft and high temperature exhaust-washed structures present new structural design challenges not found in past applications. In this work, the response of a class of thermal structures whose responses are characterized by significant amounts of restrained expansion, to which exhaust-washed structures belong, are studied. To address the complex design challenges that become evident in these investigations, structural topology optimization is applied due to its …

The Properties Of Property Alignment On The Semantic Web, Michelle Andreen Cheatham

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Ontology alignment is an important step in enabling computers to query and reason across the many linked datasets on the semantic web. This is a difficult challenge because the ontologies underlying different linked datasets can vary in terms of subject area coverage, level of abstraction, ontology modeling philosophy, and even language. The alignment approach presented here centers on string similarity metrics. Nearly all ontology alignment systems use a string similarity metric in one form or another, but it seems that the choice of a particular metric is often arbitrary. We begin this dissertation with the most comprehensive survey to date …

End-To-End Classification Process For The Exploitation Of Vibrometry Data, Ashley Nicole Smith

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Laser vibrometry provides a method to identify running vehicles' unique signatures using non-contact measurements. A vehicle's engine, size, materials, shape, and other attributes affect its vibration signature. To develop the capability to classify and identify these signatures, a robust aided target recognition (AiTR) end-to-end process is evaluated and expanded. The main challenge in classifying a vehicle's vibration signatures is presented by the operating conditions and parameters that vary as a function of sensor, environment, and collection locations on the target, among others. Some of the parameters affecting the vibration signatures include weather, terrain, sensor location, sensor type, and engine speed. …

Flash Hydrolysis Of Microalgae Biomass For Biofuels Intermediates Production, Protein Extraction, And Nutrients Recycle, Jose Luis Garcia Moscoso

Civil & Environmental Engineering Theses & Dissertations

Microalgae have shown much higher growth rates and productivity when compared to conventional agricultural crops, aquatic plants and tree species, requiring much less land area than other biodiesel feedstock. To harness that potential the hydrothermal liquefaction of algae biomass was studied and a new process called "Flash Hydrolysis" was developed to use water under subcritical conditions, this process capitalizes on the difference in reaction kinetics of algae polymeric components and fractionates proteins in liquid phase in seconds of residence time.

The main objectives for this study are: Analyze the effect of temperature in FH process to maximize the extraction of …

Association Between Vitamin D Receptor Gene Polymorphisms (Fok1 And Bsm1) And Osteoporosis: A Systematic Review, Zahra Mohammadi, Fateme Fayyazbakhsh, Mehdi Ebrahimi, Mahsa M. Amoli, Patricia Khashayar, Mahboubeh Dini, Reza Nezam Zadeh, Abbasali Keshtkar, Hamid Reza Barikani

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Osteoporosis is a Health Concern Characterized by Reduced Bone Mineral Density (BMD) and Increased Risk of Fragility Fractures. Many Studies Have Investigated the Association between Genetic Variants and Osteoporosis. Polymorphism and Allelic Variations in the Vitamin D Receptor Gene (VDR) Have Been Found to Be Associated with Bone Mineral Density. However, Many Studies Have Not Been Able to Find This Association. Literature Review Was Conducted in Several Databases, Including MEDLINE/Pubmed, Scopus, EMBASE, Ebsco, Science Citation Index Expanded, Ovid, Google Scholar, Iran Medex, Magiran and Scientific Information Database (SID) for Papers Published between 2000 and 2013 Describing the Association between Fok1 …

Fault-Tolerant Trajectory Tracking Of Unmanned Aerial Vehicles Using Immunity-Based Model Reference Adaptive Control, Brenton K. Wilburn

Graduate Theses, Dissertations, and Problem Reports (ETD)

This dissertation presents the design, development, and simulation testing of an adaptive trajectory tracking algorithm capable of compensating for various aircraft subsystem failures and upset conditions. A comprehensive adaptive control framework, here within referred to as the immune model reference adaptive control (IMRAC) algorithm, is developed by synergistically merging core concepts from the biologically- inspired artificial immune system (AIS) paradigm with more traditional optimal and adaptive control techniques. In particular, a model reference adaptive control (MRAC) algorithm is enhanced with the detection and learning capabilities of a novel, artificial neural network augmented AIS scheme. With the given modifications, the MRAC …

A Method For Non-Invasive, Automated Behavior Classification In Mice, Using Piezoelectric Pressure Sensors, Steven R. Gooch

Theses and Dissertations--Electrical and Computer Engineering

While all mammals sleep, the functions and implications of sleep are not well understood, and are a strong area of investigation in the research community. Mice are utilized in many sleep studies, with electroencephalography (EEG) signals widely used for data acquisition and analysis. However, since EEG electrodes must be surgically implanted in the mice, the method is high cost and time intensive. This work presents an extension of a previously researched high throughput, low cost, non-invasive method for mouse behavior detection and classification. A novel hierarchical classifier is presented that classifies behavior states including NREM and REM sleep, as well …

Reference Compensation For Localized Surface-Plasmon Resonance Sensors, Neha Nehru

Theses and Dissertations--Electrical and Computer Engineering

Noble metal nanoparticles supporting localized surface plasmon resonances (LSPR) have been extensively investigated for label free detection of various biological and chemical interactions. When compared to other optical sensing techniques, LSPR sensors offer label-free detection of biomolecular interactions in localized sensing volume solutions. However, these sensors also suffer from a major disadvantage – LSPR sensors remain highly susceptible to interference because they respond to both solution refractive index change and non-specific binding as well as specific binding of the target analyte. These interactions can severely compromise the measurement of the target analyte in a complex unknown media and hence limit …

Full Wave Electromagnetic Simulations Of Terahertz Wire Grid Polarizers And Infrared Plasmonic Wire Gratings, John Cetnar

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This dissertation is a study of the interaction of terahertz (THz) and long-wave infrared (LWIR) radiation with various periodic sub-wavelength metallic structures in free-space and on dielectric substrates. There are many new and useful applications for both THz and LWIR radiation. Unfortunately, heavy attenuation by the Earth's atmosphere and low output power from THz sources combine to make THz radiation weak and difficult to detect. LWIR is not as prone to atmospheric attenuation as THz radiation. Nevertheless, the detection of LWIR can be improved upon by strengthening the coupling between incoming radiation and LWIR detector systems.

Light passing through periodic …

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 …

Characterizing The Rf Performance Of The Ez430-Chronos Wrist Watch, Francisco J. Mora-Becerra, Pedro Sathler, Jay D. Carlson, Eric T. Psota, Lance C. Pérez

Department of Electrical and Computer Engineering: Faculty Publications

The Texas Instruments eZ430-Chronos development kit is a popular wireless platform for researchers, commercial developers, and hobbyists. Built into the form factor of a standard wrist watch, the Chronos is ideal for wireless body area networks (WBANs), indoor localization, and activity detection. Many of these applications requires knowledge of the RF performance of the platform, which has never been characterized by Texas Instruments nor any third parties. Here, we provide experimental data characterizing the RF performance of the eZ430-Chronos watch in various configurations, including when worn by a person while sitting, standing, and reaching. The RF performance of the Chronos …

Simulation Supported Estimation Of End-To-End Transmission Parameters In Non-Viral Gene Delivery, Beata Wysocki, Timothy M. Martin, Tadeusz A. Wysocki, Angela K. Pannier

Department of Electrical and Computer Engineering: Faculty Publications

Communications, in general, involve delivery of information from a source to a sink. At nano-scale, an example of a man-made communications involving interfacing with biological systems at intra-cellular level is non-viral gene delivery. From a telecommunications engineering perspective, important end-to-end parameters of such a system are: the endto- end delay, system capacity, and packet loss rate. There are neither known methods to estimate those parameters theoretically nor they are ready available from standard measurements. The paper provides estimates for those parameters based on the simulation of non-viral gene delivery system based on the queuing theory. The simulator used has bee

Soybean Yield, Evapotranspiration, Water Productivity, And Soil Water Extraction Response To Subsurface Drip Irrigation And Fertigation, Suat Irmak, James E. Specht, Lameck O. Odhiambo, J. M. Rees, K. G. Cassman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Soybean [Glycine max (L.) Merr.] yield, irrigation water use efficiency (IWUE), crop water use efficiency (CWUE), evapotranspiration water use efficiency (ETWUE), and soil water extraction response to eleven treatments of full, limited, or delayed irrigation versus a rainfed control were investigated using a subsurface drip irrigation (SDI) system at a research site in south-central Nebraska. The SDI system laterals were 0.40 m deep in every other row middle of 0.76 m spaced plant rows. Actual evapotranspiration (ET_a) was quantified in all treatments and used to schedule irrigation events on a 100% ET_a replacement basis in all but …

Combined Qcm-D/Ge As A Tool To Characterize Stimuli-Responsive Swelling Of And Protein Adsorption On Polymer Brushes Grafted Onto 3d-Nanostructures, Meike Koenig, Tadas Kasputis, Daniel Schmidt, Keith B. Rodenhausen Jr., Klaus-Jochen Eichhorn, Angela K. Pannier, Mathias Schubert, Manfred Stamm, Petra Uhlmann

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A combined setup of quartz crystal microbalance and generalized ellipsometry can be used to comprehensively investigate complex functional coatings comprising stimuli-responsive polymer brushes and 3D nanostructures in a dynamic, noninvasive in situ measurement. While the quartz crystal microbalance detects the overall change in areal mass, for instance, during a swelling or adsorption process, the generalized ellipsometry data can be evaluated in terms of a layered model to distinguish between processes occurring within the intercolumnar space or on top of the anisotropic nanocolumns. Silicon films with anisotropic nanocolumnar morphology were prepared by the glancing angle deposition technique and further functionalized by …

Parallel Synthesis Of Poly(Amino Ether)-Templated Plasmonic Nanoparticles For Transgene Delivery, James Ramos, Thrimoorthy Potta, Olivia Scheideler, Kaushal Rege

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Plasmonic nanoparticles have been increasingly investigated for numerous applications in medicine, sensing, and catalysis. In particular, gold nanoparticles have been investigated for separations, sensing, drug/nucleic acid delivery, and bioimaging. In addition, silver nanoparticles demonstrate antibacterial activity, resulting in potential application in treatments against microbial infections, burns, diabetic skin ulcers, and medical devices. Here, we describe the facile, parallel synthesis of both gold and silver nanoparticles using a small set of poly(amino ethers), or PAEs, derived from linear polyamines, under ambient conditions and in absence of additional reagents. The kinetics of nanoparticle formation were dependent on PAE concentration and chemical composition. …

Surface-Enhanced Raman Spectral Biomarkers Correlate With Ankle Brachial Index And Characterize Leg Muscle Biochemical Composition Of Patients With Peripheral Arterial Disease, Kim Cluff, Abby M. Kelly, Panagiotis Koutakis, Xiang N. He, Xi Huang, Yongfeng Lu, Iraklis I. Pipinos, George P. Casale, Jeyamkondan Subbiah

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Peripheral arterial disease (PAD) is characterized by atherosclerotic blockages of the arteries supplying the lower extremities, which cause a progressive accumulation of ischemic injury to the skeletal muscles of the lower limbs. This injury includes altered metabolic processes, damaged organelles, and compromised bioenergetics in the affected muscles. The objective of this study was to explore the association of Raman spectral signatures of muscle biochemistry with the severity of atherosclerosis in the legs as determined by the Ankle Brachial Index (ABI) and clinical presentation. We collected muscle biopsies from the gastrocnemius (calf muscle) of five patients with clinically diagnosed claudication, five …

The Pseudomonas Syringae Type Iii Effector Hopd1 Suppresses Effector-Triggered Immunity, Localizes To The Endoplasmic Reticulum, And Targets The Arabidopsis Transcription Factor Ntl9, Anna Block, Tania Y. Toruno, Christian G. Elowsky, Chi Zhang, Jens Steinbrenner, Jim Beynon, James R. Alfano

Nebraska Center for Biotechnology: Faculty and Staff Publications

Pseudomonas syringae type III effectors are known to suppress plant immunity to promote bacterial virulence. However, the activities and targets of these effectors are not well understood. We used genetic, molecular, and cell biology methods to characterize the activities, localization, and target of the HopD1 type III effector in Arabidopsis. HopD1 contributes to P. syringae virulence in Arabidopsis and reduces effector-triggered immunity (ETI) responses but not pathogen-associated molecular pattern-triggered immunity (PTI) responses. Plants expressing HopD1 supported increased growth of ETI-inducing P. syringae strains compared with wild-type Arabidopsis. We show that HopD1 interacts with the membrane-tethered Arabidopsis transcription factor NTL9 and …

Methyl Coenzyme M Reductase (Mcra) Gene Abundance Correlates With Activity Measurements Of Methanogenic H2/Co2-Enriched Anaerobic Biomass, Rachel Morris, Anne Schauer-Gimenez, Ujwal H. Bhattad, Colleen Kearney, Craig Struble, Daniel Zitomer, James Maki

Civil and Environmental Engineering Faculty Research and Publications

Biologically produced methane (CH₄) from anaerobic digesters is a renewable alternative to fossil fuels, but digester failure can be a serious problem. Monitoring the microbial community within the digester could provide valuable information about process stability because this technology is dependent upon the metabolic processes of microorganisms. A healthy methanogenic community is critical for digester function and CH₄ production. Methanogens can be surveyed and monitored using genes and transcripts of mcrA, which encodes the α subunit of methyl coenzyme M reductase – the enzyme that catalyses the final step in methanogenesis. Using clone libraries and quantitative …

Timoshenko Beam Model For Lateral Vibration Of Liquid-Phase Microcantilever-Based Sensors, Joshua A. Schultz, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Nicholas J. Nigro, Luke A. Beardslee, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

Dynamic-mode microcantilever-based devices are potentially well suited to biological and chemical sensing applications. However, when these applications involve liquid-phase detection, fluid-induced dissipative forces can significantly impair device performance. Recent experimental and analytical research has shown that higher in-fluid quality factors (Q) are achieved by exciting microcantilevers in the lateral flexural mode. However, experimental results show that, for microcantilevers having larger width-to-length ratios, the behaviors predicted by current analytical models differ from measurements. To more accurately model microcantilever resonant behavior in viscous fluids and to improve understanding of lateral-mode sensor performance, a new analytical model is developed, incorporating both …

Novel 3d Head And Neck Cancer Model To Evaluate Chemotherapeutic Efficacy, Kelly Morgan

Theses and Dissertations

HNSCC accounts for 7 percent of all new cancer occurrences. Despite currently available treatments, there continues to be a high mortality and recurrence rate in HNSCC. Well over 50 percent of all cancer patients receive chemotherapy as a standard treatment. However, only 5 percent of these cases have been shown to help with treatment of the disease. Formerly, two options were available for drug testing: in vivo animal models, and in vitro two-dimensional models. While in vivo models remain the most representative, their use is burdened by high costs, time constraints, and ethical concerns. 2D models are simple to use …

Experimental Development Of Advanced Air Filtration Media Based On Electrospun Polymer Fibers, Negar Ghochaghi

Theses and Dissertations

Electrospinning is a process by which polymer fibers can be produced using an electrostatically driven fluid jet. Electrospun fibers can be produced at the micro- or nano-scale and are, therefore, very promising for air filtration applications. However, because electrospun fibers are electrically charged, it is difficult to control the morphology of filtration media. Fiber size, alignment and uniformity are very important factors that affect filter performance. The focus of this project is to understand the relationship between filter morphology and performance and to develop new methods to create filtration media with optimum morphology.

This study is divided into three focus …

Analysis And Modeling Of The Roles Of Actin-Myosin Interactions In Bladder Smooth Muscle Biomechanics, Seyed Omid Komariza

Theses and Dissertations

Muscle mechanical behavior potentially plays an important role in some of the most common bladder disorders. These include overactive bladder, which can involve involuntary contractions during bladder filling, and impaired contractility or underactive bladder, which may involve weak or incomplete contractions during voiding. Actin-myosin cross-bridges in detrusor smooth muscle (DSM) are responsible for contracting and emptying the bladder. The total tension produced by muscle is the sum of its preload and active tensions. Studies suggest that actin-myosin cross-links are involved in adjustable preload stiffness (APS), which is characterized by a preload tension curve that can be shifted along the length …

The Biophysical Link Between Climate, Water, And Vegetation In Bioenergy Agro-Ecosystems, Justin E. Bagley, Sarah C. Davis, Matei Georgesu, Mir Zaman Hussain, Jesse Miller, Stephen W. Nesbitt, Andy Vanloocke, Carl J. Bernacchi

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Land use change for bioenergy feedstocks is likely to intensify as energy demand rises simultaneously with increased pressure to minimize greenhouse gas emissions. Initial assessments of the impact of adopting bioenergy crops as a significant energy source have largely focused on the potential for bioenergy agroecosystems to provide global-scale climate regulating ecosystem services via biogeochemical processes. Such as those processes associated with carbon uptake, conversion, and storage that have the potential to reduce global greenhouse gas emissions (GHG). However, the expansion of bioenergy crops can also lead to direct biophysical impacts on climate through water regulating services. Perturbations of processes …

Divergence And Flow Direction As Indicators Of Subsurface Heterogeneity And Stage-Dependent Storage In Alluvial Floodplains, Derek M. Heeren, Garey A. Fox, A. K. Fox, Daniel E. Storm, Ronald B. Miller, Aaron R. Mittelstet

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Assuming homogeneity in alluvial aquifers is convenient, but limits our ability to accurately predict stream-aquifer interactions. Research is needed on (i) identifying the presence of focused, as opposed to diffuse, groundwater discharge/recharge to streams and (ii) the magnitude and role of large-scale bank and transient storage in alluvial floodplains relative to changes in stream stage. The objective of this research was to document and quantify the effect of stage-dependent aquifer heterogeneity and bank storage relative to changes in stream stage using groundwater flow divergence and direction. Monitoring was performed in alluvial floodplains adjacent to the Barren Fork Creek and Honey …