Doctor of Philosophy, University of Toledo, 2014, Chemical Engineering

Pyrolysis is a processing technique involving thermal degradation of biomass in the absence of oxygen. The bio-oils obtained following the condensation of the pyrolysis vapors form a convenient starting point for valorizing the major components of lignocellulosic as well as algal biomass feed stocks for the production of fuels and value-added chemicals. Pyrolysis can be implemented on whole biomass or on residues left behind following standard fractionation methods. Microalgae and oil seeds predominantly consist of protein, carbohydrate and triglycerides, whereas lignocellulose is composed of carbohydrates (cellulose and hemicellulose) and lignin. The differences in the major components of these two types of biomass will necessitate different pyrolysis strategies to derive the optimal benefits from the resulting bio-oils. In this thesis, novel pyrolysis strategies were developed that enable efficient utilization of the bio-oils (and/or their vapors) from lignocellulose, algae, as well as oil seed feed stocks. With lignocellulosic feed stocks, pyrolysis of whole biomass as well as the lignin residue left behind following well-established pretreatment and saccharification (i.e., depolymerization of cellulose and hemicellulose to their monomeric-sugars) of the biomass was studied with and without catalysts. Following this, pyrolysis of (lipid-deficient) algae and lignocellulosic feed stocks, under similar reactor conditions, was performed for comparison of product (bio-oil, gas and bio-char) yields and composition. In spite of major differences in component bio-polymers, feedstock properties relevant to thermo-chemical conversions, such as overall C, H and O-content, C/O and H/C molar ratio as well as calorific values, were found to be similar for algae and lignocellulosic material. Bio-oil yields from algae and some lignocellulosic materials were similar; however, algal bio-oils were compositionally different and contained several N-compounds (most likely from pr (open full item for complete abstract)

Committee: Sasidhar Varanasi (Committee Chair); Sridhar Viamajala (Committee Co-Chair); Glenn Lipscomb (Committee Member); Arunan Nadarajah (Committee Member); Thomas Bridgeman (Committee Member) Subjects: Alternative Energy; Chemical Engineering; Energy; Sustainability

Doctor of Philosophy, Miami University, 2023, Geology and Environmental Earth Science

Solid-state ion conduction (SSIC) is a mechanism of electric current which involves the efficient transport of ions through certain crystalline materials. SSIC occurs naturally in the mineral argentite (α-Ag2S) during the growth of wire silver, and can be induced by heating acanthite (β-Ag2S) in a strong thermal gradient. Given that argentite possesses the highest ionic conductivity of any known material, the wire growth process offers a unique opportunity to study the fundamental nature of SSIC. Previous studies noted a relationship between stable Ag isotope fractionation and temperature which warranted further investigation, and thus two sets of growth experiments were devised which enabled the accurate measurement of the thermal gradient during wire formation. Wire silvers were synthesized and subjected to stable Ag isotope analysis, which clarified that the rate of heavy isotope enrichment is an increasing function of the thermal gradient. These observations are potentially relevant for applications in emerging technologies that leverage SSIC, such as atomic switches; tuning the isotopic composition of charge carriers in a device may help optimize certain side effects of ion conduction. In order to better understand the internal ion dynamics of SSIC, a reactive force field (ReaxFF) potential was developed to enable molecular dynamics (MD) simulations of Ag/S-based atomic switches. ReaxFF forcefield optimization is a notoriously difficult task, typically plagued by slow convergence and restricted to training data based on static configurations. A new high-performance optimization algorithm PAGODA was built from the ground up to enable each worker in a parallel genetic algorithm the ability to control arbitrarily parallel instances of the MD engine LAMMPS. This capability makes feasible the use of full MD simulations in the training set, unlocking the door for many new types of training data, including extended crystal structures and multi-phase composites. PAGODA (open full item for complete abstract)

Committee: John Rakovan (Committee Chair); Claire McLeod (Committee Member); Mehdi Zanjani (Committee Member); Ryan Mathur (Committee Member); Mark Krekeler (Committee Member) Subjects: Computer Science; Condensed Matter Physics; Geochemistry

Doctor of Philosophy, The Ohio State University, 2023, Food Science and Technology

Underutilized biomasses hold promise as sustainable food, feed, and fuel. As food, novel materials must be nutritious, safe, and desirable to consumers while causing minimal environmental damage. This dissertation hopes to encourage future cultivations of macroalgae and an insect, Hermetia illuscens (the Black Soldier Fly larvae, BSFL). Macroalgae and BSFL are associated with environmental benefits including low land, water, and energy demands. They are both nutritious but are not readily accepted by modern consumers as food. To facilitate their adoption, novel materials must take the shape of familiar foods. This requires processing into novel food ingredients. Environmental impacts increase as processing and materials are employed during the creation of novel ingredients. While the desirability of the final product may benefit, the process must be scrutinized to reduce resource use and ensure sustainability. Extraction and separation operations aim to concentrate a specific component, such as protein, in a single fraction. Depending on the composition, the remaining materials will also have value. Optimal co-product development requires that the influence of each process parameter be well understood. This is advantageous to processors since each additional product shares the costs and environmental impacts associated with production. The research aimed to evaluate hypotheses concerning the influence of processing parameters on material separation and physicochemical properties after biomass fractionation. The following specific objectives were addressed during this research 1) understand the nutritional quality of macroalgae and BSFL, 2) evaluate aqueous extracts from BSFL and macroalgae, 3) develop an experimental fractionation system to monitor component separation using experimental data and mass balance relationships, and 4) evaluate the effects of process parameters on the outputs of the fractionation. Macroalgae and insects were found to be promising fut (open full item for complete abstract)

Committee: Dennis Heldman (Committee Chair) Subjects: Agricultural Engineering; Food Science

Doctor of Philosophy, The Ohio State University, 2022, Food Science and Technology

Increasing population growth from the current 7.7 billion to 9.7 billion in 2050 (UnitedNations, 2022) combined with changing socio-economic background has led to an increased demand for sustainably-produced protein-rich foods. Among the different protein options, plant-based protein such as (PPI) is growing in popularity for the production of plant-based meats, snack bars, and protein powders due to its high protein content and good emulsifying functionality. However, consumers' acceptability of PPI-based food products is limited by the presence of aversive attributes such as “beany”, “grassy”, “bitter”, and “astringent”. Previous studies have focused on the characterization of volatile flavor compounds in PPI, but the understanding of the key non-volatile flavor compounds is still limited. This dissertation specifically focused on the non-volatile compounds that elicit the umami and bitter taste attributes of PPI. The umami taste attribute of pea protein ingredients can be desirable or undesirable based on the food application. The compounds contributing to the umami taste perception of PPI were investigated. Initial prep-LC sensory-guided fractionation of a 10% aqueous PPI solution revealed one well-known compound, monosodium glutamate (MSG), however it was reported at a subthreshold concentration. Umami enhancing compounds 5'-adenosine monophosphate (AMP) and 5'-uridine monophosphate (UMP) were further identified after the LC fractionations were re-evaluated with MSG. Sensory recombination studies confirmed AMP and UMP were umami enhancers of MSG and all compounds contributed approximately 81% of the perceived umami intensity of the PPI. The aversive bitter taste of pea protein ingredients limits product acceptability. Compounds contributing to the bitter perception of PPIs were investigated. Off-line multi-dimensional sensory-guided prep-LC fractionation of a 10% aqueous PPI solution revealed one main bitter compound that was identified by fourier trans (open full item for complete abstract)

Committee: Devin Peterson (Advisor); Abraham Badu-Tawiah (Committee Member); Emmanouil Chatzakis (Committee Member); Christopher Simons (Committee Member) Subjects: Food Science

Master of Science, The Ohio State University, 2022, Environment and Natural Resources

Soils represent one of the largest terrestrial stocks of carbon (C) and adopting land management techniques that increase soil C has the potential to off-set rising atmospheric CO2. Yet in order to recommend land management techniques that maximize soil C sequestration, researchers must look beyond bulk soil C budgets to investigate where, how, and for how long soil C is stored. Soil organic matter (SOM) fractionation separates bulk SOM into portions of varying stability and permanence associated with different C turnover times – including particulate organic matter (POM) (active), silt and clay (SiC) (intermediate), and resistant soil organic carbon (rSOC) (refractory) – and provides a mechanistic understanding of soil organic C (SOC) decomposition and stabilization. Changes to intermediate and refractory pools can take decades to appear, and very few studies longer than 5 years exist. Here, we seek to determine the effects of disturbance and crop diversity on the accumulation of new, corn-derived C (herein referred to as C4-C vs. “old” C3-C) in three soil fractions over 50 years of cultivation in a long-term experiment with repeated samplings. We employed size, density, and chemical fractionation, natural 13C abundance, and MIRS specific peak area analysis to identify changes in SOM composition, SOC stock (Mg ha-1), and C4-derived C stocks (Mg ha-1) of surface soil samples (0-15 cm) from the Triplett-Van Doren long-term no-tillage experiment in Wooster, OH from 1971, 2003, and 2020. Land use treatments examined were moldboard plow (PL) and no-tillage (NT), combined with continuous corn (Zea mays) (CC) and corn-soy (Glycine max) (CS) crop rotations in a full-factorial randomized complete block design. A mixed modeling approach revealed that NT and CC increased SOC stocks in POM and SiC fractions compared to PL and CS. POM made up 16.7% of total SOC, SiC 56.0%, and rSOC 4.5%. C4-derived C stocks in the SiC fraction increased over time under NT (p < 0.0001) and plate (open full item for complete abstract)

Committee: M. Scott Demyan (Advisor); Steve Culman (Committee Member); Christine Sprunger (Committee Member) Subjects: Soil Sciences

Master of Science, The Ohio State University, 2020, Environment and Natural Resources

Preserving and increasing soil organic matter (SOM) has been identified a key strategy for climate change mitigation. Plant residues, fungal and bacterial necromass, and other detritus accumulates in the soil and a portion of this SOM is protected or stabilized from further microbial mineralization. In addition to providing numerous agronomic benefits, it is thought greenhouse gas emissions could be offset through net gains in SOM and the upward climb of global temperatures could be stalled or even reversed. However, storage of atmospheric carbon as SOM is only effective as a climate change mitigation strategy if SOM associated C remains in the soil long-term, i.e. more than 100 years. Soil organic matter stabilization is known to be controlled by several key mechanisms, i.e. physical occlusion, polyvalent cation bridging, weak interactions like hydrogen bonding and Van der Waals forces, and ligand exchange. These physical and chemical stabilization mechanisms vary in the protection they provide SOM; physical occluded SOM is weakly protected as compared to SOM protected via ligand exchange. While these stabilization mechanisms and the affects they have on SOM have been known for some time, much regarding the soil properties associated with these mechanisms and SOM they stabilize remain a mystery. Measurements of SOM and other soil properties important for SOM stabilization are necessary for modeling changing soil C levels over time. However, conventional laboratory methods for assessing these soil properties are time consuming and expensive for large numbers of samples. Visible near-infrared spectroscopy (Vis-NIRS) is a rapid method and inexpensive technique for predicting soil properties. Multivariate statistical approaches are used in conjunction with reference soil data representative of the study area to calibrate and validate models, which if a sufficient level of accuracy is achieved can be used to predict unknown samples only with the VNIR spectra. Ther (open full item for complete abstract)

Committee: M. Scott Demyan Dr. (Advisor); Steven Culman Dr. (Committee Member); Brian Slater Dr. (Committee Member) Subjects: Agriculture; Agronomy; Environmental Science; Soil Sciences

Doctor of Philosophy, The Ohio State University, 2020, Earth Sciences

In the ocean and on land, many biogeochemical processes have feedbacks on climate. How these processes affect climate or respond to climate changes over long timescales is not always well understood as they are difficult to study in the modern day. The research reported here aims to better understand some of these processes, specifically erosion and sediment deposition, as well as the biogeochemical cycling of barium in the oceans. This research is separated into four projects that use geochemical and computational techniques to link long-term regional climate changes with atmosphere and ocean dynamics. The first two projects use samples from the Arabian Sea, collected during International Ocean Discovery Program Expedition 355 Arabian Sea Monsoon. During this expedition two sites were drilled, Sites U1456 and U1457 located within Laxmi Basin in the Arabian Sea. Samples range in age from 0-11 Ma. In project one, strontium isotope ratios (87Sr/86Sr) from pore fluids from Sites U1456 (n = 21) and U1457 (n = 20) were measured to characterize diagenetic reactions. Pore fluid 87Sr/86Sr is useful to establish fluid-rock reactions, sources, and fluid mixing that may have occurred after deposition, processes that could influence the signal recorded by proxy records from these marine sediment cores. The measured pore fluid 87Sr/86Sr has significant variations at both sites and three distinct zones of diagenetic processes are identified, with similar characteristics at both sites. In the second project, 87Sr/86Sr (n=127) and neodymium isotopes (εNd) (n=38) are measured from the separated clay fraction in sediments from the same cores to investigate their provenance. Provenance is the geographic origin of sediments deposited in a basin and is important to reconstruct so we can understand sediment pathways and constrain paleoclimate and erosion records. The records produced are also compared to 87Sr/86Sr and εNd of the carbonate-free bulk sediment from the same sites in ord (open full item for complete abstract)

Committee: Elizabeth Griffith (Advisor); Andrea Grottoli (Committee Member); Matthew Saltzman (Committee Member); Audrey Sawyer (Committee Member) Subjects: Geochemistry; Geology; Paleoclimate Science

Doctor of Philosophy, The Ohio State University, 2020, Pharmaceutical Sciences

Cancer remains the second-leading cause of death and more than 1.5 million people cancer will be diagnosed with this disease in the U.S. alone in 2020, with the mortality rate projected to be above 9 million worldwide. The availability of cancer treatments is still somewhat limited and many are expensive. Therefore, more affordable treatments from sustainable resources need to be found and utilized. Compounds derived from natural sources have been major contributors to the area of cancer chemotherapy for decades. Secondary metabolites from terrestrial and marine organisms have afforded numerous purified compounds, both in their unmodified naturally occurring forms and as semi-synthetic derivatives. Such compounds have been obtained primarily from terrestrial microbes and higher plants, with some found in marine animals. The presently available natural product oncology agents exhibit a variety of cellular mechanisms of action. As part of an ongoing effort to discover anticancer drug leads from tropical plants, a large-scale collection of Glycosmis ovoidea Pierre (Rutaceae) was made at Nui Chua National Park, Dahang Village, Vietnam. This taxonomically authenticated plant material was collected by abiding to the stipulations of currently accepted international conventions. Activity-guided fractionation of the chloroform-soluble fractions led to the isolation of compounds representing two different structural classes, a flavonoid and several coumarins. The new compound 1-(7-methoxy-2-oxo-2H-chromen-8-yl)-3-methyl-1-oxobut-2-en-2-yl (S)-2-methylbutanoate (147) was characterized structurally, and is a prenylated coumarin ester. This was isolated along with nine other compounds that were previously known, namely, murracarpin (141), 5,3'-dihydroxy-3,6,7,8,4'-pentamethoxyflavone (142), 7-hydroxycoumarin (143), murrayone (144), murralongin (145), kimcuongin (146), murragatin (148), minumicrolin (149), and minutuminolate (150). In order to confirm its structure and configura (open full item for complete abstract)

Committee: A. Douglas Kinghorn Ph.D., D.Sc. (Advisor); Karl Werbovetz Ph.D. (Committee Member); Pui-Kai Li Ph.D. (Committee Member) Subjects: Pharmacy Sciences; Philosophy of Science

Doctor of Philosophy, The Ohio State University, 2020, Earth Sciences

The expansion of unconventional petroleum development enhanced production of natural gas and oil globally, but also raised concerns related to groundwater contamination resulting from drilling activities. Extensive research recently has focused on identifying contaminants (e.g., CH4, brines) related to drilling or natural processes, as well as the processes that emplace these contaminants into shallow groundwater systems. The integrated utilization of inert (e.g., noble gas), hydrocarbon (e.g., C1/C2+, compound-specific stable isotopes), and aqueous geochemical tracers has become a standard technique for identifying naturally-occurring hydrocarbon gas or brine from human-induced contamination. Still, it is often difficult to make determinations of groundwater contamination due to lack of understanding of the many processes that can alter the hydrocarbon and aqueous geochemistry following emplacement into groundwater (post-genetic modification) and a lack of baseline geochemical data. Advection, diffusion, mixing with primary microbial gas, microbial oxidation, and secondary methanogenesis can all obfuscate the geochemical characterization of a groundwater system making it essential to understand the effects of these individual processes. Here, numerical models were developed using a hypothetical thermogenic natural gas to illustrate how traditional geochemical tracers are affected by post-genetic modification following gas emplacement. The current work also examined the aqueous and gas geochemistry of groundwater samples collected from observation boreholes and residential drinking-water wells in the Saint-Edouard region of southern Quebec, Canada, and from drinking-water wells that were previously interpreted to contain fugitive gas contamination in Parker County, TX. In the Saint-Edouard region, the widespread presence of hydrocarbons in shallow groundwater and the relative lack of petroleum development provides a rare opportunity to understand naturall (open full item for complete abstract)

Committee: Thomas Darrah Ph.D. (Advisor); Franklin Schwartz Ph.D. (Committee Member); W. Berry Lyons Ph.D. (Committee Member); Michael Barton Ph.D. (Committee Member) Subjects: Geochemistry

Master of Science, Miami University, 2018, Geology and Environmental Earth Science

An unusual metal isotope fractionation has been observed in association with the growth of wire silver, whose unique texture and morphology can be explained by superionic conduction of Ag+ in Ag2S. This constitutes the first recognition of mass migration by fast ion conduction in nature. Stable Ag isotope analysis revealed natural wire silver is normally enriched in the heavy isotope 109Ag, while common fractionation mechanisms would predict the opposite. In synthetic wires grown at high temperature (>450°C), this fractionation is amplified by an order of magnitude more than expected by any known isotope effect. This may indicate a previously unrecognized isotope fractionation mechanism associated with superionic conductors in nature and in general, which would have important implications for the geochemistry of ore deposits, as well as fast-ion technologies including atomic switches and solid-state ion batteries.

Committee: John Rakovan (Advisor); Mark Krekeler (Committee Member); Elisabeth Widom (Committee Member) Subjects: Geochemistry; Mineralogy

Doctor of Philosophy, University of Toledo, 2017, Chemical Engineering

Liquid fuels from microalgal biomass have become less attractive recently due to the fall in prices of petroleum and natural gas. However, interest in microalgae as a renewable feedstock for value-added bioproducts such as oleo-chemicals and sugar-derived platform molecules has been on the rise. This is due to the economic and environmental benefits associated with the processing of these higher value products from microalgae biomass. Microalgae biomass consists mainly of carbohydrate, protein and lipids. When efficiently fractionated, the lipid and carbohydrate portions could be used for synthesizing oleochemicals and sugar-based platform molecules, respectively. The protein rich residue could serve as feed for animals. This study is a part of the microalgae processing methodologies being explored in our group, with the purpose of developing an integrated approach for producing renewable high value chemicals from microalgae via environmentally sustainable pathways. For this purpose, a specific pathway for processing microalgae after it is harvested following cultivation is proposed. The proposed pathway entails subjecting harvested microalgae to enzymatic digestion to fractionate and affect depolymerization of the individual fractions: Simple sugars resulting from the hydrolysis of the carbohydrate fraction can be converted to value-added products via fermentation using product-specific microorganisms. Similarly, oleic acid, the major component of the lipid fraction, can form the feed-stock for the production of value-added compounds such as industrial nylon precursors. As conventional (chemical/physical) methods of isolating carbohydrates from microalgae are deemed unsustainable, in our first project we explored an enzymatic hydrolysis method for isolation of simple sugars directly from microalgae biomass. Lipids are isolated from the enzymatically digested algal slurry through immiscible solvent extraction. Following phase separation, the aqueous phas (open full item for complete abstract)

Committee: Sasidhar Varanasi (Committee Chair); Sridhar Viamajala (Committee Co-Chair); Kana Yamamoto (Committee Member); Maria Coleman (Committee Member); Patricia Relue (Committee Member) Subjects: Chemical Engineering; Organic Chemistry; Polymers; Sustainability

Doctor of Philosophy, The Ohio State University, 1976, Graduate School

Committee: Not Provided (Other) Subjects: Health Sciences

Doctor of Philosophy, The Ohio State University, 2016, Chemistry

Even with extensive genomic and transcriptomic characterization of tumors, the relationship of the human cancer genotype to cancer phenotype remains unclear. Proteins, however, are the immediate molecular drivers of the cancer phenotype that govern tumorigenesis or tumor recurrence. The research described here highlights work on non-small cell lung cancer tumors and cell lines. The major goals are to discover proteins exclusive to tumor recurrence and liver kinase B1 (LKB1) gene mutation, respectively. The proteins were discovered by nanoflow multidimensional liquid chromatography coupled to mass spectrometry. The goal of the research described in Chapter 2 of the dissertation focuses on establishing a mass spectrometry-based bottom-up proteomic method for protein detection in formalin-fixed paraffin embedded (FFPE) tissue specimens. Identification of protein markers for lung cancer requires tumor tissues that are usually unavailable in the fresh, frozen state. FFPE tissues, however, are produced from resected tumor material and are readily available for proteome analysis. The use of these tumor samples in mass spectrometry demands effective sample preparation and detection strategies. In the analysis, the use of an on-slide deparaffinization method and modified lysis buffer recovered the maximum amount of protein from the slide tissue specimen and reduced the sample incubation time during digestion. Fractionation of peptide digests into fifteen high pH reversed phase fractions followed by low pH reversed phase separation resulted in the highest number of protein identifications for a minimum amount of tissue protein extract when coupled to an optimized mass spectrometry method. In Chapter 3, the use of this method for the tumor protein analysis yielded over five thousand proteins per cohort. The corresponding changes at protein level were identified by comparing the proteins discovered in specimens from recurrent to those of nonrecurrent patients. Adenocarcinom (open full item for complete abstract)

Committee: Vicki Wysocki (Advisor); David Carbone (Committee Member); Susan Olesik (Committee Member); Abraham Badu-Tawiah (Committee Member) Subjects: Chemistry

PHD, Kent State University, 2015, College of Arts and Sciences / Department of Earth Sciences

Barite (BaSO4) which incorporates Sr in its crystal structure (~10,000 ppm Sr; Averyt et al., 2003) precipitates at only a few subaerial springs worldwide via either microbial processes (e.g., Senko et al., 2004) or abiotic processes (e.g., Bonny and Jones, 2008b). Significant mass dependent strontium (Sr) isotopic fractionation has been identified recently in many types of natural samples with a potential use as a paleo-environmental proxy related to temperature, presence of microbes, source of Sr and secondary mineral precipitation (e.g. Krabbenhoft et al., 2010; Bohm et al., 2012). Understanding the controls on variations in stable Sr-isotopes between natural samples and within sample types may provide important information on biogeochemical cycling and processes involving Sr. Both synthetic and natural barite samples were analyzed using field and laboratory techniques. Stable Sr isotopic fractionation was examined in abiotically precipitated barite at given conditions (e.g., temperature, saturation index, Sr/Ba ratio in solution) in the absence of microbes (Widanagamage et al., 2014). It is suggested that saturation index and the temperature of the solution are the two major controls on strontium distribution coefficient, Kd(Sr) which indirectly influence stable Sr isotope fractionation during barite precipitation. Authigenic barite samples precipitated in modern continental settings (warm water springs) were examined to elucidate processes controlling mass dependent fractionation of Sr during barite precipitation. Barite precipitation mechanisms at these spring sites are biologically mediated. Barite crystal morphology changes with rate of diffusion and rate of precipitation. It is suggested that sulfate concentration in the solution is more important in barite crystal morphology than temperature (Kowacz et al., 2007). However, my study suggests that temperature influences barite crystal morphology more than Ba2+/SO42- ratio in the solution. None of the g (open full item for complete abstract)

Committee: David Singer Dr. (Advisor) Subjects: Environmental Geology; Environmental Science; Geobiology; Geochemistry; Geology

Doctor of Philosophy, University of Akron, 2015, Biomedical Engineering

Three-dimensional (3D) cell culture technologies have gained a considerable momentum in compound screening applications to identify novel anti-cancer drugs. Increasing evidence shows substantial differences between responses of cancer cells to drug compounds in monolayer cultures (2D) traditionally used in drug discovery and in vivo during preclinical tests. 3D cell cultures more closely resemble tumors in terms of close cell-cell and cell-extracellular matrix interactions, non-uniform distribution of soluble factors, and presence of hypoxic cells. As such, they provide a relevant tumor model to elicit more realistic responses from cells treated with drugs. Screening of libraries of compounds to identify novel drugs requires high throughput 3D culture platforms that produce consistently sized cancer cell spheroids and allow convenient drug testing and analysis of cellular responses. In this study, we introduce a novel, automated technology for 3D culture of cancer cell spheroids in a high throughput format. Aqueous two-phase systems (ATPS) are used for producing spheroids with robotic tools and standard equipment. ATPS are formed by mixing appropriate mass concentrations of two biocompatible polymers such as dextran (DEX) and polyethylene glycol (PEG). A nano-liter drop of the denser aqueous DEX phase containing cancer cells is robotically dispensed into each well of a non-adherent 96-well plate containing the immersion PEG phase solution. A round drop containing cells forms at the bottom of the well while overlaid with the aqueous PEG phase. Cells remain in the DEX drop and form a spheroid, which receives nutrients from the immersion phase through diffusion into the drop. The fidelity of the ATPS spheroid culture technology depends on favorable partition of cells to the DEX drop. We investigate partition of cancer cells in ATPS and demonstrate the effect of interfacial tension between the two aqueous phases on the distribution of cells in ATPS. To facilitate (open full item for complete abstract)

Committee: Hossein Tavana (Committee Chair) Subjects: Biomedical Engineering

Doctor of Philosophy, The Ohio State University, 2015, Pharmacy

Leishmaniasis is an infectious disease caused by blood-borne parasites from the genus Leishmania. The therapeutic options currently available for this potentially deadly and disfiguring disease are limited in their number and availability to at-risk populations, and also cause severe toxicity and side effects. An increasing incidence of drug resistance has also been developing among clinical strains of Leishmania parasites. There is thus a great need for the discovery and development of new antileishmanial agents. Natural products research has historically been a successful avenue for the discovery of new drugs and lead molecules for medicinal chemistry optimization efforts. This may be because natural products tend to be structurally complex and suited for interaction with various drug targets in biological systems. Through collaborative studies on the in vitro antileishmanial activities of plants growing in Ohio, the extract produced from bald cypress (Taxodium distichum) cones was found to be active and was selected for phytochemical investigation. Additionally, a chemically diverse set of 234 molecules in a library of previously isolated plant natural products was tested against L. donovani, which is responsible for the fatal (visceral) manifestation of leishmaniasis. T. distichum cone extract has been used in traditional medicine practices for many indications, such as treatment of the parasitic disease, malaria. The bioactivity-guided fractionation of this extract has led to the observation of in vivo activity of one crude subfraction of the chloroform partition (TDCD3F2), in mice infected with L. donovani. Several new molecules were isolated from this sample, including a para-benzoquinone containing abietane diterpenoid (103), a para-benzoquinone containing seco-abietane diterpenoid (105), and two rearranged abietane diterpenoids (109 and 110), along with 12 previously known compounds. These molecules were tested for their antileishmanial activities, o (open full item for complete abstract)

Committee: A. Douglas Kinghorn (Advisor); Esperanza J. Carcache de Blanco (Committee Member); James R. Fuchs (Committee Member) Subjects: Chemistry; Medicine; Pharmacy Sciences

Master of Science (MS), Wright State University, 2008, Earth and Environmental Sciences

Crystal Lakes are a group of four interconnected lakes, located in southwestern Clark County, Ohio. Several studies have looked at separate geochemical and isotopic information at this location. However, no one has thoroughly studied the relationship between the algal community, geochemistry, and carbon isotope fractionation within Crystal Lake. The fractionation of carbon isotopes of dissolved inorganic carbonate is greatly affected by the process of photosynthesis; the amount of photosynthesis is affected by the amount of algae in the aquatic community; the amount of algae is affected by the available nutrients in system. Therefore, there should be a correlation between the nutrients in the water column, the amount of algae, and the extent of carbon isotope fractionation. If such a correlation is found, it could be used as a proxy for paleonutrient availability. To determine this correlation, water samples were collected via submersible pump every 1.5 meters at approximately the deepest location in Crystal Lake. Several parameters that are important indicators of photosynthesis, such as dissolved oxygen and pH, were measured in situ. The collected samples were analyzed for nutrient and chlorophyll content; samples were also sent out for carbon isotope analysis. The measured values of δ13C in Crystal Lake are highest in areas of photosynthesis, and decrease in the hypolimnion where decomposition of accumulated biomass occurs. There is a clear trend between carbon isotope fractionation and photosynthetic indicators, such as dissolved oxygen and pH. Trends between several nutrient concentrations and fractionation was also observed. Samples with δ13C values less than -10 per mille V-PDB have pH values below 8 and little dissolved oxygen (0-1 mg/L). Samples with δ13C values between -9 and -6 per mille V-PDB have pH values greater than 8, dissolved oxygen levels between 5-20 mg/L, silica concentrations below 3.25 mg/L, magnesium concentrations below 27 ppm, and calc (open full item for complete abstract)

Committee: Songlin Cheng PhD (Committee Co-Chair); Rebecca Teed PhD (Committee Co-Chair); David Dominic PhD (Committee Member) Subjects: Biogeochemistry; Chemistry; Geochemistry; Hydrology

PhD, University of Cincinnati, 2007, Arts and Sciences : Geology

Three episodes of alkaline volcanism of Quaternary age have been recognized in the Kula Volcanic Province (KVP) in Western Turkey. The alkaline volcanic rocks of the KVP vary in composition from basanite to tephriphonolite and from trachybasalt to basaltic trachyandesite. Measured values for 87Sr/86Sr and 143Nd/144Nd in the rocks of the KVP range from 0.703029 to 0.703534 and 0.512773 to 0.512998, respectively, (Gulec, 1991; Alici, et al., 2002) suggesting that an isotopically depleted mantle component is involved in the genesis of the Kula lavas. This mantle component is also enriched in the most incompatible elements, as shown by OIB-like primitive mantle normalized multi-element patterns, this indicates that enrichment of the mantle source is probably a recent event. The pMELTS algorithm of Ghiorso, et al., (2002) can be used to show that low degrees of partial melts, generated by fractional melting of a spinel peridotite mantle source (Maaloe and Aoki, 1977), can produce the alkaline magmas of the KVP. Assuming an underlying heat source, I used pMELTS to model the melting behavior of an average spinel peridotite mantle composition at melting at 23 kbar (~80 km) in the presence of 0.1% H2O at fO2 = QFM-1. The degree of partial melting is 8% for the KVP rocks and the primary magma composition is then subjected to polybaric fractional crystallization from 23 to 4 kbar. The compositional diversity displayed by the Kula volcanic rocks is reproduced successfully by the pMELTS polybaric fractionation calculations when the dP/dT gradient is set to 42 and 25 in the mantle and crust, respectively, and the oxygen fugacity is increased from one log unit below to one log unit above the QFM buffer at 13 kbar. Generation and evolution of the Kula magmas were simulated successfully by using pMELTS. Eight per cent fractional melting of an average spinel lherzolite composition at 23 kbar generated the primary magma and polybaric fractional crystallization simulations with changin (open full item for complete abstract)

Committee: Dr. Attila Kilinc (Advisor) Subjects: Geology

Master of Science, The Ohio State University, 2009, Soil Science

In vitro gastrointestinal methods can potentially provide a rapid and inexpensive measure of bioaccessible arsenic which in turn can be used to conduct more accurate and site-specific human health risk assessments of contaminated soils. However, in order for in vitro methods to become widely accepted as tools that accurately assess soil As exposure through the oral ingestion pathway, a better understanding of the fractions of soil arsenic that are measured by the in vitro extraction and the underlying soil properties associated with As bioaccessibility (BA) are needed. In this study, nineteen soils with a wide range of soil properties were spiked with 250 mg/kg As. Bioaccessible As was then determined using The Ohio State University in vitro gastrointestinal method (OSU-IVG) and soil As was fractionated using a four-step sequential extraction. There was a wide range in As BA; from 27.3 to 206 mg/kg with a mean of 94.7 mg/kg in the gastric phase, and from 29.0 to 210 mg/kg in the intestinal phase with a mean of 98.6 mg/kg. Highly significant (P < 0.0001) relationships existed between bioaccessible As and the combination of soil pH and Fe extracted by citrate bicarbonate dithionite (Fecbd) or soil pH and Fe extracted by acid ammonium oxalate (Feox). Soil pH explains more of the variation in bioaccessible As (r2 = 0.67) than Fecbd (r2 = 0.45) or Feox (r2 = 0.38). The sequential extraction results indicate that As extracted from non-specifically sorbed (F1) and specifically sorbed (F2) fractions provide a good measure of pH and iron oxide (Fecbd and Feox) controlled As BA (GE, r2 = m = 1.06; IE, r2 = 0.94, m = 1.07). However, the addition of amorphous or poorly-crystalline oxides of Fe (F3) and well-crystallized oxides of Fe (F4) as extractable As fractions to F1 and F2 dies not improve the correlation with bioaccessible As. Therefore, the total As content of soil overestimates and is a poor indication of bioaccessible As. The largest contribution to bioaccessible As is (open full item for complete abstract)

Committee: Nicholas Basta (Advisor); Jerry Bigham (Committee Member); Linda Weavers (Committee Member); Elizabeth Dayton (Committee Member) Subjects: Environmental Science

Doctor of Philosophy, The Ohio State University, 2009, Soil Science

The soil organic carbon (SOC) pool is very important as a potential sink of C over human time scales. In order to evaluate the potential of soils as a long-term C sink in response to changing management and climate, it is essential to be able to experimentally partition different SOC fractions. Despite many advances in the understanding of SOC dynamics, numerous uncertainties still exist in the separation of SOC fractions with distinct stability. Therefore, the overall objective of this research was to acquire a better understanding of the stable SOC fraction in terms of pool size, structural composition, and turnover rates in two soils of the Midwestern United States (Typic Fragiudalf of Wooster, OH and Aquic Argiudoll of Monmouth, IL). Both physical and chemical fractionation methods were employed to isolate the stable from labile SOC. Comparison of the commonly used chemical oxidizing agents, namely hydrogen peroxide (H2O2), disodium peroxodisulphate (Na2S2O8), and sodium hypochlorite (NaOCl), revealed that both H2O2 and Na2S2O8 are more effective than NaOCl in isolating a stable SOC fraction enriched with alkyl-C groups and a radiocarbon age of thousands of years old. Evaluation of the physical fractions indicated that (i) sand and silt-associated SOC quickly changed with conversion from native vegetation to agricultural crops, and (ii) the clay associated SOC in agricultural soils of Wooster continues to increase, albeit at a slower rate, with increase in total SOC, while it attained maximum saturation capacity in the Mollisol at Monmouth. In general, the pool size of the stable SOC fractions isolated by physical methods was significantly higher (10.7 to 64.8% of total SOC) than that isolated by chemical methods (1.3 to 25.6% of total SOC). Combining physical and chemical methods isolated a stable SOC fraction with longer stability in the surface soils than the individual methods, while the different methods did not influence substantially the turnover rates of (open full item for complete abstract)

Committee: Rattan Lal (Advisor); Jerry Bigham (Committee Member); Peter Curtis (Committee Member); Robert Hoeft (Committee Member) Subjects: Soil Sciences