Doctor of Philosophy, The Ohio State University, 2023, Food, Agricultural and Biological Engineering

Container grown plants are used for nursery production, ornamental plants and increasingly for food production. In containerized plant production, soilless substrates are the growing medium which serve to anchor plants, as well as provide water, nutrients, and air for healthy root growth. The chemical and physical properties of soilless substrates have been examined in several studies, but few have studied the biological communities microbiomes in these media. Those investigating biological communities often focus on a specific group or plant response to specific pathogens. The overall microbial communities in soilless substrates have not been investigated or optimized. In this study, broad questions related to microbial communities were addressed including the composition of microbial communities, the predominant microorganisms and their dynamics, and the effects of specific components. The effects of these microbial communities and whether they are beneficial to plant health versus simply altering the physical and chemical properties were also addressed. As part of this study, experiments were conducted to determine the uniformity of the microbial community throughout the container vertical profile, and to determine if a novel leaching method could be substituted for destructive sampling to characterize microbial communities during plant growth. To address these questions, a nucleic acid based approach was used. The bacterial and fungal communities from the ii substrates were characterized by isolating total DNA, PCR amplifying 16s rRNA genes and ITS regions, sequencing them and comparing them to databases of these sequences. In one study, bacterial and fungal communities in the components of a typical commercial pine bark soilless substrate and their dynamics in mixes, with and without compost, were characterized; their impact on plant growth throughout a typical production cycle were evaluated and compared. Results showed that the microbial community composit (open full item for complete abstract)

Committee: Frederick C. Michel Jr. (Advisor); Peter P. Ling (Committee Member); Anna L. Testen (Committee Member); Christopher G. Taylor (Committee Member); James E. Altland (Committee Member); Sami Khanal (Committee Member) Subjects: Bioinformatics; Environmental Science; Horticulture; Molecular Biology; Plant Sciences; Soil Sciences

Master of Science in Chemistry, Youngstown State University, 2023, Department of Biological Sciences and Chemistry

Today's society is mainly dependent on fossil energy sources despite being not sustainable, not renewable, and not environmentally friendly, as they generate a lot of carbon dioxide. Hydrogen is a promising substitute for fossil fuels. It is a clean fuel with water as the only oxidation product, thus less production of CO2. Cadmium telluride (CdTe) is a promising semiconductor material that could facilitate the use of solar energy in producing hydrogen gas. CdTe can be a p-type photoelectrode that can perform electron transfer processes with an electrolyte. As a cathode, it reduces hydrogen ions in water to form hydrogen gas. Spray pyrolysis method, which is simple and easy to use, cheap compared to vacuum deposition methods, can produce uniform films over large surfaces within a short time, many small substrates at the same time, and whose concentration of precursor solution remains constant with time, was used in this project. CdTe films for this project were fabricated on stainless steel 304 substrates at different substrate temperatures and spray times. The precursor solution was based on a mixture of CdCl2, TeO2, hydrazine, and EDTA. Characterization of the fabricated films was done using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS), stylus profilometry, cyclic voltammetry, and linear sweep voltammetry. The fabricated CdTe films had a uniform and highly crystalline surface morphology, that was Te-rich (p-type) and exhibited photoactivity with the evolution of hydrogen gas. The best photoelectrode was fabricated by spraying a mixture of equal volumes of 0.02 M solutions of Cd and Te salts onto a SS 304 substrate held at 330°C for 3 min, which produced a 10 µm-thick film and a photocurrent of 5800 µA/cm2 observed at -0.5 V. When a dispersion of Pt catalyst was reduced onto it, a photocurrent of 7700 µA/cm2 was observed at -0.5 V, which compares well with other fabrication methods.

Committee: Clovis Linkous PhD (Advisor); Christopher Arntsen PhD (Committee Member); Allen Hunter PhD (Committee Member); Joe Simeonsson PhD (Committee Member) Subjects: Analytical Chemistry; Chemistry

Master of Science, The Ohio State University, 2021, Environmental Science

Permafrost thaw in northern latitudinal peatlands is likely to create a positive feedback to climate change, as previously frozen soil carbon (C) becomes bioavailable and is released to the atmosphere as carbon dioxide (CO2) or methane (CH4). The loss is the result of microbially mediated transformations of “old” permafrost C, “new” C from plant inputs, and intermediate-age C in the seasonally thawed active layer. The microbiome, and its encoded carbon-processing potential, changes with thaw, but the realized effect on substrate utilization and gas emissions has not been characterized. We, therefore, examined how microbial C cycling changed in two sequential thaw stages (a Sphagnum-dominated bog and a sedge-dominated fen) in Stordalen Mire (68.35°N, 19.05°E), in northern Sweden, using two incubation-based methods. We characterized the diversity and extent of microbial C substrate utilization across a wide range of substrates by Biolog EcoplatesTM, under dilute aerobic conditions. To test specific substrate hypotheses under more field-relevant conditions, with parallel quantification of microbiome shifts and C gas emissions, we amended anaerobic microcosms with selected substrates (glucose, acetate, butyrate, galacturonic acid, and p-hydroxybenzoic acid). The initial and final microbiomes were characterized via 16S rRNA amplicon sequencing. Biolog incubations revealed a higher diversity and faster rate of overall substrate utilization in the fully thawed fen than in the bog, especially in amine, carbohydrate, and carboxylic acid substrate groups. Anaerobic incubations indicated habitat differences in microbial use of key substrates, higher CH4 and CO2 production in the fen compared to the bog, and lower CO2:CH4 ratios in the fen reflecting the greater role of methanogenesis. Changes in the CO2:CH4 ratio with depth were larger in the bog, paralleling its greater microbiome shifts with depth. The substrates that induced the greatest shifts in both gas production and (open full item for complete abstract)

Committee: Virginia Rich Dr. (Advisor); Gil Bohrer Dr. (Committee Member); Matt Davies Dr. (Committee Member); Jessica Ernakovich Dr. (Committee Member) Subjects: Climate Change; Environmental Science

PhD, University of Cincinnati, 2020, Arts and Sciences: Chemistry

Noble metal nanoparticles have been used as sensors utilizing the phenomenon localized surface plasmon resonance (LSPR). LSPR based sensors are competitive because of the high sensitivity and can be made label-free. LSPR sensors have great potential as diagnostic tools for point-of-care and in-field scenarios. In this work, I have developed three unique sensors that utilizes LSPR. First, a nanoparticle-based localized surface plasmon resonance (LSPR) assay to detect copper ions in biological samples in vitro was developed. After reducing the cellular Cu2+ ions to Cu+ ions using ascorbic acid, a `click' reaction is carried out to covalently couple a dye to the surface of a gold nanoparticle array. Then utilizing the ability to fabricate LSPR arrays on substrates we developed durable flexible nanoparticle substrates for point-of-care sensing. Second, I developed a rapid, LSPR based diagnostic test for chlamydia without the need for amplification. This technique can be developed into a strip and be used for other STIs in a multiplexed manner. Last, a flexible plastic, sensitive sensor for cortisol and neuropeptide y was developed. These sensors show low limits of detection, good reproducibility, and good selectivity in complex biological samples. Moreover, they all show excellent promise as point-of-care sensors which can greatly expand medical diagnostics for at-home and in the field use.

Committee: Laura Sagle Ph.D. (Committee Chair); Peng Zhang Ph.D. (Committee Chair); In-Kwon Kim Ph.D. (Committee Member); Pearl Tsang Ph.D. (Committee Member) Subjects: Analytical Chemistry

Doctor of Philosophy, Case Western Reserve University, 2020, Chemistry

Stable isotopomers of biological molecules or xenobiotics can be utilized to probe the metabolic pathways with which these compounds are involved. By introducing these labeled substrates into living systems, we can use techniques such as mass spectrometry to track the fates of the isotopically labeled atoms. One set of projects described herein focuses on the synthesis of these substrates for use by collaborating laboratories. Of particular interest to our lab are biomolecules known as lipid peroxidation (LPO) products. These molecules are formed in increased concentrations during periods of oxidative stress. In the past, our lab has discovered metabolic pathways that allow for catabolism of the ubiquitous LPO product 4-hydroxynonenal. In order to better understand these pathways, we need to identify the enzymes that affect the steps of each pathway. It also stands to reason that there may be other pathways that exist for additional families of LPO products. To this end, I describe work done on the isolation of the kinase involved in 4-HNE metabolism as well as synthesis of epoxyketooctadecenoic acids for use in additional metabolic studies. The final topic of study involves the confirmation of the identity of a novel metabolite 4-(aminomethyl)malonate. Results from a previous study led us to hypothesize the existence of this molecule. Synthesis of both isotopically unlabeled and labeled analogues of this molecule was completed and utilized to confirm the identity of the molecule. An in vivo study was conducted where rats were fed β-alanine, the proposed metabolic precursor to this molecule. The tissue specific concentration of AMM formed during periods of high β-alanine was tracked and its effect on neurotransmitters was assessed.

Committee: Gregory Tochtrop Ph.D. (Advisor); Henri Brunengraber Ph.D. M.D. (Committee Member); Clemens Burda Ph.D. (Committee Member); Daniel Scherson Ph.D. (Committee Member); Robert Salomon Ph.D. (Committee Chair) Subjects: Chemistry

Doctor of Philosophy (PhD), Wright State University, 2019, Electrical Engineering

Since the discovery of graphene, two-dimensional (2D) materials have attracted intensive interests in the past 15 years and there has been a growing interest in exploring new materials beyond graphene, such as silicene, germanene, etc. Numerous papers have been published to demonstrate their extraordinary electronic, optical, biological, and thermal properties which render broad applications in various fields. However, the absence of band gap in graphene and silicene prohibits their uses in digital applications. This dissertation reviews recent progress on band gap opening based on mono- and bi- layer silicene and presents a new silicon atomic structure which exhibits a 0.17 eV bandgap. In addition, a feasible approach was first demonstrated and proposed to potentially achieve the industrial-scale production of our simulated structure. More broadly, this approach suggests a new path for growing any materials on different substrates without forming chemical bond between the interaction layers. Although the gapless character of graphene prohibits its use in digital applications, it is not a concern for Radio Frequency (RF) applications. This work also investigated the impact of defects to RF electronic properties of the 2D materials. Chemical vapor deposited Graphene (CVDG) was selected as an example and was measured using scanning microwave microscopy (SMM). In order to analyze the result, a numerical model of SMM was first developed using Electromagnetic Professional (EMPro). From the results, both conductivity and permittivity of defective graphene exhibit the frequency-dependency properties. Additionally, the model we proposed in this work can precisely characterize the correlation between conductivity and permittivity of any materials in nanoscale at RF level.

Committee: Yan Zhuang Ph.D. (Advisor); Henry Chen Ph.D. (Committee Member); Lok C. Lew Yan Voon Ph.D. (Committee Member); Marian K. Kazimierczuk Ph.D. (Committee Member); Saiyu Ren Ph.D. (Committee Member) Subjects: Electrical Engineering; Electromagnetics; Materials Science; Physics

Master of Science (MS), Ohio University, 2016, Plant Biology (Arts and Sciences)

Acid Mine Drainage (AMD) from pre-regulation mining affects streams in the Appalachian region resulting in acidic waters with high dissolved metal content. Previous studies have shown remediated stream segments have better water quality and biological communities than untreated streams, but these segments have not attained the same biological quality as streams unaffected by AMD. Phosphorus limitation of the biofilm community has been hypothesized as a contributing factor. Nutrient limitation was tested in four stream categories using nutrient diffusing substrates: AMD, transitional, recovered and unimpacted. Chlorophyll a, a measure of photosynthetic biomass, was significantly higher in phosphorus treatments. In addition, the phosphorus treatments had lower phosphorus-acquiring enzyme activities compared to the control. The phosphorus with nitrogen treatment showed an increase in polyunsaturated fatty acids, having higher nutritional value for grazers. This study demonstrated that nutrient availability has a substantial impact on the photosynthetic component of biofilms in impaired and remediated streams.

Committee: Morgan Vis (Advisor); Jared DeForest (Committee Member); Kelly Johnson (Committee Member) Subjects: Ecology; Freshwater Ecology

Master of Science (MS), Bowling Green State University, 2015, Physics

Surface Enhanced Raman Spectroscopy is a powerful analytical tool to obtain information on molecular composition. This technique has advanced greatly since its discovery, allowing Raman spectroscopic analysis down to the detection of single molecule. The heart of SERS performance lies on the choice and fabrication of SERS substrate. The most investigated metals for SERS substrates are Au and Ag. Unfortunately, the fabrication of such devises poses a significant challenge due to an expensive deposition technology including, vapor deposition, electron-beam lithography, focused ion-beam lithography, and nano-transfer printing. Herein, we report a simple and low-cost solution processing method to fabricate SERS substrates. Au nanoparticles and Au/CdS core/shell nanoparticles were synthesized and their solutions deposited on glass plates in the form of nanoparticle films. Although the enhancement of Raman signal due to Ag nanoparticle substrates is greater than that of Au, the high stability and a wide variety of fabrication methods makes Au nanoparticles more favorable candidates for SERS substrates. The performance of the SERS substrates fabricated using this method was found to be comparable with the commercially available substrates.

Committee: Mikhail Zamkov (Advisor); Lewis Fulcher (Committee Member); Alexey Zayak (Committee Member) Subjects: Materials Science

Doctor of Philosophy, University of Akron, 2014, Polymer Engineering

Ordering of block copolymer (BCP) thin films has been great interest for potential applications due to nanometer scale size self-assembly pattern formation. Numerous methods (chemical, physical, etc.) have been developed to create desired alignment and ordering properties in such block copolymer systems. However, the drawback of most current technologies such as brittleness and lack conformability to different surfaces makes them difficult to implement new emerging high-tech flexible technologies. On the other hand, there is a lack of knowledge in block copolymer wettability characteristics and morphological behavior on soft substrates which makes them attractive to explore for further investigations. A notable challenge in this regard is that successful deployment of BCPs for applications requires an understanding of BCP ordering properties on flexible substrate as a function of their surface chemistry, topography including patterning, roughness, stiffness, modulus and thermal conductivity, etc. Therefore, the general purpose of this research is to investigate the thermodynamics and kinetics of directed assembly of cylinder and lamellar forming polystyrene-block-polymethlymethacrylate (PS-b-PMMA) diblock copolymer films on elastomeric polydimethylsiloxane (PDMS) substrates with controlled surface energy and substrate topography. In first part, wettability characteristics of cylinder and lamellae forming PS-b-PMMA thin films versus surface energy of elastomeric PDMS substrates were increasing surface energy of PDMS by tuning with Ultraviolet Ozone (UVO) exposure and elasticity by varying the crosslinking concentration. In this extended wetting regime gradual perpendicular to parallel orientation change was shown for lamellar BCP films unlike cylindrical films where the transition was very sharp, reflecting lamellar BCP intrinsic stability over a wider range of substrate surface energy, consistent with theoretical estimates. In second part of the study, we extended (open full item for complete abstract)

Committee: Alamgir Karim Dr. (Advisor); Mukerrem Cakmak Dr. (Committee Member); Matthew Becker Dr. (Committee Member); Kevin Cavicchi Dr. (Committee Member); Jutta Luettmer-Strathmann Dr. (Committee Member) Subjects: Polymers

Doctor of Philosophy, The Ohio State University, 2013, Chemical and Biomolecular Engineering

CO2 capture from fuel and flue gases is critical to reducing the anthropogenic influence on climate change. Solvent absorption-, adsorption- and membrane-based processes have been widely studied for this application. Compared to the former two alternatives which are equilibrium-based, membrane separation is rate-based and does not involve phase change. Membranes hold great promise for CO2 capture due to their potentially lower energy consumption compared to other processes, operational simplicity with no handling of steam and condensed phases, lower water consumption, compactness, and ease of maintenance due to absence of moving parts. CO2 (H2S)-selective membranes with appropriate separation capabilities can be used to separate CO2 from waste gases in a fossil fuel-based power plant or both CO2 and H2S from syngas streams containing hydrogen. They can also be integrated with water gas shift (WGS) reaction for effective CO, CO2 and H2S clean up. In the context of hydrogen purification for fuel cells, a detailed 2-D model incorporating mass, energy and pressure drop equations for describing the transport in an intricate spiral-wound WGS membrane reactor was developed and validated using prior experimental data. Such a configuration is also used in state-of-the-art water purification processes and was the preferred choice for the advanced gas separation membranes studied in this work. A simplified 1-D version of the same model was then combined with a detailed cost methodology to study the feasibility of membrane processes for post-combustion CO2 capture (PCC) in a coal-based power plant. From this study, valuable insights into the membrane properties required to meet the economic goals of PCC were gained. As a part of the experimental work, we first scaled up an existing amine-based facilitated transport membrane to purify hydrogen for fuel cells. The membranes were then characterized for their separation performance using a gas permeation set-up and compared w (open full item for complete abstract)

Committee: W.S. Winston Ho PhD (Advisor); Stuart Cooper PhD (Committee Member); David Tomasko PhD (Committee Member) Subjects: Chemical Engineering

Master of Science, The Ohio State University, 2012, Dentistry

OBJECTIVE: The purposes of this study were to assess and compare the colors of porcelains produced using a newly introduced Press-on-Metal (PoM) technique and the conventional layered technique for various illuminations, and further to compare the colors obtained with high-gold, low-gold, high-palladium and palladium-silver alloys as substrates for each of these two technologies. METHODS: One high-gold, low-gold, high-palladium and palladium-silver alloy were used and the resultant colors and color differences were evaluated after application of body porcelain by the two techniques on each alloy under each of 4 CIE Illuminants (A, D50, D65, and F3). For the conventional layering technique, B1 dentin porcelain was applied by conventional porcelain layering, condensation and firing. For the PoM technique, the shade A1/B1 was applied by waxing, investment, pressing, divesting and then cleaning. All specimens for both techniques were subjected to reflectance measurement by a non-contact measuring system. Color parameters were obtained and color differences between the two techniques were calculated. A repeated measures analysis of variance was performed for each of the CIE color parameters with the repeated factor Illuminant, and the Porcelain Technique, and Metal Substrate as the primary factors, and with all 2nd and 3rd order interactions. Further, reported thresholds of human perceptibility and acceptability were used to evaluate the differences found. RESULTS: For the lightness color direction L*, the magnitude of differences in the illuminants was under the perceptibility threshold. For the red-purple to blue-green color coordinate a*, the magnitude of these differences exceeded acceptability thresholds. Statistically significant differences were found in L* between the two ceramic techniques for the high-gold and high-palladium metal substrates for all 4 illuminants, and for the low-gold metal substrate for each of the illuminants A and F3. The magnitude of these (open full item for complete abstract)

Committee: William Johnston (Advisor); Willaim Brantley (Committee Member); Do-Gyoon Kim (Committee Member) Subjects: Dental Care; Dentistry; Materials Science

Doctor of Philosophy, The Ohio State University, 2009, Electrical and Computer Engineering

The use of step-graded SiGe buffers to accommodate the lattice constant difference between Si and III-V materials is an extremely promising approach to achieve monolithically integrated III-V optoelectronic device technology on Si wafers. The potential of this technology has already been demonstrated by the integration of numerous high performance GaAs-InGaP based devices on Si substrates. As a result, there is now a great interest in knowing the basic properties of residual defects within the III-V/SiGe materials and devices since their understanding is fundamental to maintain the progress achieved to date. The focus of this research if to investigate “grown in” defects present within GaAs and InGaP-based layers and devices grown on SiGe/Si generating a fundamental understanding on defect introduction in lattice mismatch III-V/SiGe heteroepitaxy. The role of the SiGe substrate is analyzed by comparing deep level properties with identical structures grown on GaAs substrates. Results showed that the presence of dislocations do not introduced additional deep levels. In addition, and from the point of view of the technology, the effect of radiation damage in III-V/SiGe PV structures is analyzed, specifically detection and identification of “ambient-generated” defects that result from the application of these materials and photovoltaic devices operating in the space environment. In this dissertation the first radiation study for III-V/SiGe structures was performed. Results indicated that for single junction GaAs structures, the primary impact of the SiGe/Si substrate was to improve the radiation-tolerance of these devices, in particular for n+p GaAs diodes. While DLTS results showed generally lower radiation-induced trap concentrations for both n-type and p-type GaAs grown on SiGe compared to growth on conventional substrates, the reduction was far more dramatic for p-type GaAs. The improved radiation-tolerance for GaAs grown on SiGe/Si is attributed to interactions bet (open full item for complete abstract)

Committee: Steven Ringel A (Advisor); Wu Lu (Other); George Valco J (Other); Dennis Guenther A (Other) Subjects: Materials Science

Doctor of Philosophy, The Ohio State University, 2008, Horticulture and Crop Science

Increased environmental awareness combined with a decrease in available water for irrigation has required the nursery industry to evaluate water and nutrient efficiencies. The production of plants in containers reduces the rooting volume available to the plant by about 95% resulting in a limited reservoir of moisture and nutrients. The substrates most commonly used in container production are soilless and porous, with pine bark comprising all or at least a majority of the substrate. This production environment requires nursery producers to irrigate daily to maximize plant performance. As irrigation volume increases both water and nutrient efficiencies decrease. This work investigates the interactions of irrigation, fertilizer rate, and water and nutrient efficiencies.A plant-integrated, gravimetric, substrate moisture monitoring system was used to control irrigation volume and limit leachate volumes to near-zero levels. Effective container capacity (ECC) was used to determine irrigation volumes and frequency. ECC was defined as the maximum mass of the container, substrate and plant unit after gravitational water loss. The system used the ECC target to deliver irrigation within a narrow range of substrate moisture contents to study the effects of irrigation volume on growth, water use, and nutrient uptake of baldcypress (Taxodium distichium L.). In the summer of 2006, the gravimetric substrate monitoring system was proven as an effective, plant-integrated method of reducing leachate volume that required minimal maintenance under the four month experimental period. Under a near-zero leachate irrigation system, irrigation volume and leachate volume (by definition) are decreased; substrate nutrient concentration was increased resulting in increased plant tissue nutrient concentration, and an increase in water-use efficiency. Nitrogen use efficiency was not affected by irrigation regime in this study, as fertilizer rate impacted uptake of nitrogen.

Committee: Daniel Struve PhD (Advisor); James Metzger PhD (Committee Member); Hannah Mathers PhD (Committee Member); Robert Hansen PhD (Committee Member) Subjects: Horticulture

Doctor of Philosophy, The Ohio State University, 2005, Chemical Engineering

Lactic acid has been widely used in food and pharmaceutical industries. Recently, the worldwide demand has been increasing due to many new industrial applications. Lactic acid bacteria have been used in lactic acid production because of their high growth rate and product yield. However, the limitations including costly substrates and complicated product recovery make bacterial fermentation economically unattractive. In contrast, filamentous fungi such as Rhizopus oryzae can directly produce optically pure L(+)-lactic acid from carbohydrates present in agricultural residues and plant biomass; therefore, can overcome the problems in bacterial fermentation. However, change and diversity of fungal morphology during fermentation cause many problems in reactor control and operation, and affect lactic acid production. In this research, fungal morphology was controlled by immobilization in a Rotating Fibrous Bed Bioreactor (RFBB). It was found that RFBB provided good morphological control and improved oxygen transfer resulting in increased lactic acid production, limited undesirable ethanol production, and stable long-term production in the RFBB. Lactic acid production cost can be minimized by using low-value substrates derived from agricultural residues and plant biomass. The results showed that R. oryzae was capable of utilizing both starchy materials present in agricultural residues and pentose sugars derived from hemicellulose to produce lactic acid. Process engineering techniques were used to improve lactic acid production. It was found that overgrown immobilized cells in the RFBB caused oxygen limitation and lowered lactic acid production. Oxygen limitation was prevented by increasing oxygen transfer rate using high aeration rate or supplying oxygen-enriched air. Controlling cell growth and biofilm thickness by shaving-off the fungal mycelia under high shear rates and limiting the nitrogen source in the medium was also studied. To achieve controlled growth and immobil (open full item for complete abstract)

Committee: Shang-Tian Yang (Advisor) Subjects: Engineering, Chemical

Doctor of Philosophy, The Ohio State University, 2005, Molecular Genetics

Eukaryotic cells utilize a network of signal transduction pathways to sense their environment and control their growth and proliferation. Protein kinases are a large group of enzymes that coordinate responses to extracellular and intracellular stimuli via phosphorylation of specific downstream targets. In S. cerevisiae , growth is controlled, in part, by the Ras signaling pathway via the cAMP-dependent protein kinase, PKA. PKA is a serine/threonine-specific protein kinase that has been shown to regulate any aspects of cell growth and metabolism in this budding yeast and other eukaryotes. Unfortunately, finding protein kinase substrates by conventional methods is a difficult and time-consuming task. As a result, few targets of any given protein kinase are known. To simplify this task, we developed an evolutionary proteomics strategy for the identification of PKA substrates in S. cerevisiae and related yeast species. This evolutionary proteomics approach is sequenced-based and takes advantage of the fact that most PKA substrates contain the consensus sequence, R-R-x-S/T-B. In this consensus, “x” refers to any amino acid, “B” to hydrophobic residues and “S” or “T” to the site of phosphorylation. The general approach consists of two basic steps. In the first, we identified all of the proteins in the S. cerevisiae proteome that contain this PKA target consensus sequence. In the second, we asked whether these potential target sites are conserved in the orthologous proteins present in other budding yeast species. For this latter step, we used the recently released genome sequences of six different yeast, including five Saccharomyces species and Candida albicans. The underlying premise of this approach is that PKA sites important for general aspects of cell biology are more likely to be conserved across these evolutionary distances. We are presently testing this basic premise with a small number of proteins predicted to be physiologically relevant PKA substrates. In this th (open full item for complete abstract)

Committee: Paul Herman (Advisor) Subjects: Biology, Molecular

Master of Science (MS), Ohio University, 1995, Chemical Engineering (Engineering)

The atmospheric chemical vapor deposition of titanium nitride on polyimide substrates

Committee: Daniel Gulino (Advisor) Subjects: Engineering, Chemical

Master of Science (MS), Ohio University, 1995, Chemical Engineering (Engineering)

Silicon carbide coatings by plasma-enhanced chemical vapor deposition on silicon and polyimide substrates

Committee: Daniel Gulino (Advisor) Subjects: Engineering, Chemical

Master of Science (MS), Ohio University, 2000, Chemical Engineering (Engineering)

Residual stress in gallium nitride films grown on silicon substrates by metalorganic chemical vapor deposition

Committee: Daniel Gulino (Advisor) Subjects: Engineering, Chemical

Master of Science (MS), Ohio University, 2006, Environmental Studies (Arts and Sciences)

Correlations between fish community structure, substrate particle size distributions, and physical habitat quality were investigated in wadeable and headwater reference streams within the Western Allegheny Plateau ecoregion (WAP) of southeast Ohio. An historic dataset was also utilized to determine fish-habitat correlations, as well as habitat and fish community stability. The reference sites were found to display considerable fish community persistence and physical habitat stability over time. In the absence of sediment impairments, the fish communities showed minimal correlations with substrate variables at headwater and wadeable sites. An overall lack of correlations between fish and physical habitat data were displayed at wadeable sites, while several fish variables were correlated with drainage area and pool quality at headwater sites. These results suggest that fish communities at wadeable sites might be shaped by other factors, such as biotic interactions, and that the main factor influencing headwater communities may be water and/or habitat availability.

Committee: Matthew White (Advisor) Subjects:

Doctor of Philosophy, Case Western Reserve University, 1994, Electrical Engineering

This dissertation contains three main topics. The first one is the development of the dynamic source reversal method, based on potential theory with the help of the Tangent method, to characterize microstrip discontinuities. Detailed analysis of microstrip open-end and symmetrical and asymmetrical gap discontinuities, with anisotropic substrates, is carried out. The second one is to develop an efficient and accurate method to solve coplanar waveguide dispersion. The method uses the conformal mapping technique to derive the general expressions, as seen for the first time in the literature, for the sources on the central strip and ground planes of coplanar waveguide. These expressions are also proved to be very useful and precise to treat microstrip propagation characteristics. The third topic is to extend the dynamic source reversal method to characterize coplanar waveguide discontinuities with the help of the known propagation characteristics for no discontinuity obtained in the second topic. Detailed calculations for CPW open end discontinuities are accomplished in the transform domain. All the problems studied for these three topics include anisotropic substrates. The results for the three topics show very good accuracy and excellent efficiency. Some comparisons with th e results obtained by other methods proposed by authors are included.

Committee: R.E. Collin (Advisor) Subjects: