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Design And Synthesis Of Nanomaterials For Surface-Enhanced Raman Scattering, Fuel Cell Technology, And Photonics, Pedro Camargo
Design And Synthesis Of Nanomaterials For Surface-Enhanced Raman Scattering, Fuel Cell Technology, And Photonics, Pedro Camargo
All Theses and Dissertations (ETDs)
In the first part of my dissertation, I developed two approaches for selectively probing the SERS activities of individual hot spots, i.e., experimentally detect the SERS signals only for the molecules that are trapped within the hot-spot region in individual Ag nanoparticle dimers. Then, I performed a systematic investigation on the SERS activity of individual dimers composed of two closed spaced Ag nanoparticles. By utilizing Ag nanoparticles displaying a variety of well-defined shapes, sizes and orientations to construct the dimers, I were able to precisely correlate the detected SERS signals to the specific geometry of individual hot spots. In the …
Growth Factor Delivery From Fibrin Matrics Containing Affinity-Based Delivery Systems To Treat Peripheral Nerve Injury, Matthew Wood
Growth Factor Delivery From Fibrin Matrics Containing Affinity-Based Delivery Systems To Treat Peripheral Nerve Injury, Matthew Wood
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This thesis work sought to develop a biomaterial to further the understanding of affinity-based delivery and to serve as a potential treatment for peripheral nerve injury. The use of an affinity-based delivery system: ABDS) with growth factors in a nerve guidance conduit: NGC) was hypothesized to promote nerve regeneration and functional recovery following a critical nerve defect. Evaluation of affinity-based delivery using peptides with varying binding affinity for heparin determined that peptide binding affinity for heparin affected the release rate and biological activity of nerve growth factor: NGF) in vitro. The ABDS presented biologically active NGF, which promoted neurite extension …
Engineering The Optical Properties Of Gold Nanostructures For Biomedical Applications, Leslie Au
Engineering The Optical Properties Of Gold Nanostructures For Biomedical Applications, Leslie Au
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This research investigated the synthesis and optical properties of Au nanostructures with an aim to use them as imaging agents and photothermal transducers for the diagnosis and treatment of cancer. I have produced Au nanocages with hollow interiors and porous walls using the galvanic replacement reaction between Ag nanocubes and AuCl4-. I have engineered these Au nanocages to have localized surface plasmon resonance: LSPR) peaks in the near-infrared region with strong absorption. These optical properties allow for the imaging of biological tissues at deeper penetration and the photoablation of cancer. By replacing AuCl4- with AuCl2 …
Electrocorticographic Neural Correlates Of Arm Movements And Associated Goal Orientation In Humans, Nicholas Anderson
Electrocorticographic Neural Correlates Of Arm Movements And Associated Goal Orientation In Humans, Nicholas Anderson
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This thesis analyzed the cortical representation of arm kinematics, target encoding, and goal encoding using subdural electrocorticographic: ECoG) recordings in humans. Using a joystick-based visuomotor task, subjects performed both a standard, delayed match-to-sample center-out task as well as a circular tracing task. Spectral analyses of the ECoG signals clearly showed significant cosine tuning for hand velocity, direction, position and speed throughout the cortex. In particular, velocity tuning was best represented spectrally in a high gamma band from around 90-150 Hz in the primary motor cortical regions. In dorsolateral prefrontal cortex: DLPFC), cortical activity in the 150-250 Hz band of the …
Investigations Into The Ulnar Response To Mechanical Stimuli Activating Lamellar And Woven Bone Formation, Jennifer Mckenzie
Investigations Into The Ulnar Response To Mechanical Stimuli Activating Lamellar And Woven Bone Formation, Jennifer Mckenzie
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Woven and lamellar bone formation can be stimulated using mechanical loading. Woven bone forms rapidly in response to damaging loading in a disorganized manner with low mineral density. In contrast, lamellar bone formation can be induced in the absence of damage, and is characterized by its slow, organized deposition and high density. In this dissertation, we first examined the molecular response to woven and lamellar bone formation using damaging and non-damaging dynamic loading protocols, respectively. We observed a significant increase in gene expression related to angiogenesis, cell proliferation and osteogenesis prior to woven bone formation, with significantly lower levels of …
Development And Implementation Of Fully 3d Statistical Image Reconstruction Algorithms For Helical Ct And Half-Ring Pet Insert System, Daniel Keesing
Development And Implementation Of Fully 3d Statistical Image Reconstruction Algorithms For Helical Ct And Half-Ring Pet Insert System, Daniel Keesing
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X-ray computed tomography: CT) and positron emission tomography: PET) have become widely used imaging modalities for screening, diagnosis, and image-guided treatment planning. Along with the increased clinical use are increased demands for high image quality with reduced ionizing radiation dose to the patient. Despite their significantly high computational cost, statistical iterative reconstruction algorithms are known to reconstruct high-quality images from noisy tomographic datasets. The overall goal of this work is to design statistical reconstruction software for clinical x-ray CT scanners, and for a novel PET system that utilizes high-resolution detectors within the field of view of a whole-body PET scanner. …
Oxy-Coal Combustion: Submicrometer Particle Formation, Mercury Speciation, And Their Capture, Achariya Suriyawong
Oxy-Coal Combustion: Submicrometer Particle Formation, Mercury Speciation, And Their Capture, Achariya Suriyawong
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Energy is the issue of great importance at the present. Coal, the cheapest and the most abundant reserve fossil fuel, is currently one of the most widely used energy source globally and will continue to be in the foreseeable future. The use of coal has also posed many world-wide environmental challenges, including the control of particulate matter, mercury, and trace metals, and carbon oxide: CO2) emissions. The rising of CO2 level in the atmosphere due to burning of fossil fuels is one of the major factors contributing to the global climate change. Capturing CO2 from coal combustion exhaust has been …
Making Metal And Semiconductor Contacts On Alkanethiolate Self-Assembled Monolayer Adsorbed On Au, Peng Lu
Making Metal And Semiconductor Contacts On Alkanethiolate Self-Assembled Monolayer Adsorbed On Au, Peng Lu
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Understanding and controlling the interactions of metals and semiconductors with organic substrates is critical to many technological applications. The primary goal of the research described in this dissertation is to understand the metal/organic and semiconductor/organic interactions and to develop methods to fabricate stable and robust metallic and semiconducting contacts on organic thin layers. Alkanethiolate self-assembled monolayers: SAMs) adsorbed on Au, which have highly organized structures with a uniform density of terminal organic functional groups, were employed as model organic systems. Chemical vapor deposition: CVD) was employed to deposit selectively aluminum and alumina on functionalized SAMs. Methods were also developed to …
Optical Measurements In Gas-Liquid Stirred Tanks, Sean Mueller
Optical Measurements In Gas-Liquid Stirred Tanks, Sean Mueller
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This dissertation outlines the development of novel, in-situ and relatively inexpensive optical measurement techniques for use in opaque multiphase reactors at elevated temperature: 350 ┬░C) and pressure: 180 bar) environments where conventional measurement techniques either cannot be used or are difficult or expensive to implement. Important parameters: such as gas holdup, specific interfacial area, bubble velocity, bubble chord lengths, liquid level, and phase transition) in opaque, multiphase reactors at industrially relevant conditions are lacking in the literature. A miniaturized 4-point probe is developed and methodology outlined that can simultaneously capture local gas holdup, interfacial area, size, and velocities of bubbles …
Zeolites For Cleaner Processes: Alkylation Of Isobutane And N-Butene, Subramanya Nayak
Zeolites For Cleaner Processes: Alkylation Of Isobutane And N-Butene, Subramanya Nayak
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Large pore beta zeolite with straight and zig-zag channels and USY zeolite with super cages have shown potential to replace toxic and hazardous mineral acids as catalysts in alkylation processes. However, due to rapid deactivation of these zeolites, their acceptance in industrial alkylation has been delayed. In this study we seek a deeper understanding of the kinetics, transport, and sorption of organic molecules used in alkylation processes in nano-porous zeolites. A six lump kinetic model that considers the key reactions for the zeolite catalyzed alkylation process is presented. The influence of different reactions and rate limiting steps on catalyst, and …
Enzymatic Enhancement Of Water Removal In The Dry Grind Corn To Ethanol Process, Ana Beatriz Thomas
Enzymatic Enhancement Of Water Removal In The Dry Grind Corn To Ethanol Process, Ana Beatriz Thomas
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The removal of water from coproducts in the fuel ethanol process requires a significant energy input. The drying of the coproducts is responsible for as much as 32% of the total utilities cost of the process. In this study, improvements in the energy and water balances of the corn to ethanol process and a decrease in ethanol production costs were achieved. Significant reductions in water-binding capacity of whole stillage were found for two, commercially available, cell wall degrading enzymes, GC220 and MGC. The addition of a protease, GC106, during fermentation was found to significantly enhance ethanol production rates as well …
Contributions To The Methodology Of Electrocardiographic Imaging (Ecgi) And Application Of Ecgi To Study Mechanisms Of Atrial Arrhythmia, Post Myocardial Infarction Electrophysiological Substrate, And Ventricular Tachycardia In Patients, Yong Wang
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ABSTRACT OF THE DISSERTATION Contributions to the Methodology of Electrocardiographic Imaging: ECGI) and Application of ECGI to Study Mechanisms of Atrial Arrhythmia, Post Myocardial Infarction Electrophysiological Substrate, and Ventricular Tachycardia in Patients by Yong Wang Doctor of Philosophy in Biomedical Engineering Washington University in St. Louis, 2009 Professor Yoram Rudy, Chair Electrocardiographic Imaging: ECGI) is a noninvasive imaging modality for cardiac electrophysiology and arrhythmia. ECGI reconstructs epicardial potentials, electrograms and isochrones from body-surface electrocardiograms combined with heart-torso geometry from computed tomography: CT). The application of a new meshless method, the Method of Fundamental Solutions: MFS) is introduced to ECGI with …
Electrocardiographic Consequences Of Electrical And Anatomical Remodeling In Diabetic And Obese Humans, Shuli Wang
Electrocardiographic Consequences Of Electrical And Anatomical Remodeling In Diabetic And Obese Humans, Shuli Wang
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Background. Diabetes and obesity are two major risk factors for cardiovascular disease. Both can cause changes due to cardiac sources in body-surface potentials: BSPs), that is, in electrocardiograms: ECGs). By identifying the major effects of diabetes and obesity on BSPs, we hope to reveal the electrical phenotype of diabetes in body-surface ECGs in the presence of obesity. Methods. A Bidomain Platform was constructed to link heart-surface transmembrane potentials: TMPs) and BSPs. The Forward-Problem Module of the platform calculates BSPs from a bidomain-model of myocyte TMPs and torso anatomy. The platform also contains a Cardio-myocyte TMP Estimation Module in which an …
Oxygen-Enhanced Combustion: Theory And Applications, Scott Skeen
Oxygen-Enhanced Combustion: Theory And Applications, Scott Skeen
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In the broadest sense, oxygen-enhanced combustion: OEC) refers to the use of oxygen to improve combustion and/or process characteristics. When a stream of oxygen is available, a wide range of flame configurations is possible. This work considers two specific configurations of OEC and is divided into two parts. In Part I, fundamental experimental and numerical flame studies explore the combustion of gaseous fuel/inert mixtures in oxygen-enriched air or pure oxygen under well-defined conditions. Part II targets a more practical application by considering the combustion of solid fuels in a variety of oxygen/carbon dioxide mixing scenarios. For gaseous non-premixed flames, combining …
Aerosol Filtration And Separation, Tachih Hsiao
Aerosol Filtration And Separation, Tachih Hsiao
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ABSTRACT OF THE DISSERTATION Aerosol Filtration and Separation by Ta-Chih Hsiao Doctor of Philosophy in Energy, Environmental, & Chemical Engineering Washington University in St. Louis, 2009 Professor Da-Ren Chen, Advisor Particle control technologies are essential in many manufacturing industries: chemical, electronic, mineral, and food and beverages) as well as in pollution abatement and environmental control: for example, clean rooms and post processing of power plant emissions). A variety of particle control technologies using different physical forces and various collection substrates have been developed over the last 100 or so years. Among these technologies, filtration is known as the most economical …
Improving The Cathode Conditions By Pressurizing And Carbon Dioxide Addition To Enhance The Practicality Of Mfc Treatment Of Wastewater, Jeffrey Fornero
Improving The Cathode Conditions By Pressurizing And Carbon Dioxide Addition To Enhance The Practicality Of Mfc Treatment Of Wastewater, Jeffrey Fornero
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An increasing global energy demand coupled with a more rigorous governmental regulatory environment: including identifying carbon dioxide as a pollutant) is becoming more and more incompatible with engineering practices that were developed in an era of lower energy costs and less regulation. It is, therefore, not a surprise that researchers are looking towards bioelectrochemical systems: BESs) as a potential superior technology to produce environmentally-benign and sustainable energy, replace energy intensive processes, and/or produce chemical products. The overall tenet of my thesis-based research was to understand the important mechanisms that limit the power output for BESs during wastewater treatment and to …
Expression Analysis And Stem Cell Engineering, Cara Rieger
Expression Analysis And Stem Cell Engineering, Cara Rieger
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The overall goal of the thesis was to develop tools to advance Investigations of stem cells in tissue engineering therapeutics for neurodegenerative disease and spinal cord injury. Two tools to characterize cell fate and a tool to separate a subset of neural cells were developed and evaluated. In the first study, a digital PCR technology, called polonies, was applied to measure mRNA from several key stem cell genes in small numbers of ES cells. Due to its properties, we hypothesized that polonies would be uniquely poised to profile stem cells. Polonies were counted for Oct3 in a sample of 10 …
Modeling And Identification Of Differentially Regulated Genes Using Transcriptomics And Proteomics Data, Thanura Elvitigala
Modeling And Identification Of Differentially Regulated Genes Using Transcriptomics And Proteomics Data, Thanura Elvitigala
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Photosynthetic organisms are complex dynamical systems, showing a remarkable ability to adapt to different environmental conditions for their survival. Mechanisms underlying the coordination between different cellular processes in these organisms are still poorly understood. In this dissertation we utilize various computational and modeling techniques to analyze transcriptomics and proteomics data sets from several photosynthetic organisms. We try to use changes in expression levels of genes to study responses of these organisms to various environmental conditions such as availability of nutrients, concentrations of chemicals in growth media, and temperature. Three specific problems studied here are transcriptomics modifications in photosynthetic organisms under …
Improving Biocompatibility By Controlling Protein Adsorption: Modification And Design Of Biomaterials Using Poly(Ethylene Glycol) Microgels And Microspheres, Evan Scott
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Guided by the clinical needs of patients and developments in biology and materials science, the primary focus of the biomaterials field remains at the solid/liquid interface between biomaterial surfaces and biological fluids. For blood-contacting devices, biological responses are initially elicited and directed by proteins that adsorb from this multicomponent solution to form thin films on their surfaces. The identity, conformation, and quantity of adsorbed proteins are related to the properties of a material's surface. For example, hydrophobic surfaces tend to be thrombotic via interactions between platelets and adsorbed fibrinogen, while surface-activation of specific enzymes initiates the coagulation cascade on hydrophilic …
A Framework For Temperature Imaging Using The Change In Backscattered Ultrasonic Signals, Yuzheng Guo
A Framework For Temperature Imaging Using The Change In Backscattered Ultrasonic Signals, Yuzheng Guo
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Hyperthermia is a cancer treatment that elevates tissue temperature to 40 to 43oC. It would benefit from a non-invasive, safe, inexpensive and convenient thermometry to monitor heating patterns. Ultrasound is a modality that meets these requirements. In our initial work, using both prediction and experimental data, we showed that the change in the backscattered energy: CBE) is a potential parameter for TI. CBE, however, was computed in a straightforward yet ad hoc manner. In this work, we developed and exploited a mathematical representation for our approach to TI to optimize temperature accuracy. Non-thermal effects of noise and motion confound the …
Metal Oxide Semiconductors For Solar Energy Harvesting, Elijah Thimsen
Metal Oxide Semiconductors For Solar Energy Harvesting, Elijah Thimsen
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The correlation between energy consumption and human development illustrates the importance of this societal resource. We will consume more energy in the future. In light of issues with the status quo, such as climate change, long-term supply and security, solar energy is an attractive source. It is plentiful, virtually inexhaustible, and can provide more than enough energy to power society. However, the issue with producing electricity and fuels from solar energy is that it is expensive, primarily from the materials: silicon) used in building the cells. Metal oxide semiconductors are an attractive class of materials that are extremely low cost …
Getting To The Point: Bridging The Gap Between Simple And Complex Catalytic Systems Using Temporal Analysis Of Products (Tap), Xiaolin Zheng
Getting To The Point: Bridging The Gap Between Simple And Complex Catalytic Systems Using Temporal Analysis Of Products (Tap), Xiaolin Zheng
All Theses and Dissertations (ETDs)
One of the key issues in the field of catalysis is to relate the catalyst structure/composition to its activity/selectivity. One way to understand this relationship is to understand the individual role each catalyst component plays in the chemical reaction. Industrial catalysts can be extremely complex in structure and to understand their reaction kinetics, researchers often study simpler surfaces such as single crystals using surface science techniques. This introduces a well-known problem in the field of catalysis commonly referred to as the "pressure and materials gap." Typically, industrial catalyst research is performed under process conditions, which means operating pressures of one …
Feature Topography And Sound Intensity Level Encoding In Primary Auditory Cortex, Paul Watkins
Feature Topography And Sound Intensity Level Encoding In Primary Auditory Cortex, Paul Watkins
All Theses and Dissertations (ETDs)
The primary auditory cortex: A1) in mammals is one of the first areas in the neocortex that receives auditory related spiking activity from the thalamus. Because the neocortex is implicated in regulating high-level brain phenomena, such as attention and perception, it is therefore important in regards to these high-level behaviors to understand how sounds are represented and transformed by neuronal circuits in this area. The topographic organization of neuronal responses to auditory features in A1 provides evidence for potential mechanisms and functional roles of this neural circuitry. This dissertation presents results from models of topographic organization supporting the notion that …
Open Collaborative Mechanical / Product Design - User As Developer A New Design Methodology For Internet Era Business Innovations And Entrepreneurship, Jing Zheng
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In product design and development projects, the most important part is identifying user needs. Traditional methods such as surveys, focus group studies and interviews are expensive and sometime inaccurate in identifying those needs. Inspired by the open source software development, along with the research that has been done on the "lead user" method, the method of using collective customer wisdom to modify old products or even develop new products has become an emerging new design method and is starting to get popularity and success. However, the effectiveness of such method comparing to the traditional face to face "close" development method …