Master of Science (MS), Bowling Green State University, 2020, Biological Sciences

Agricultural fields in Northwest Ohio and the Maumee River watershed are frequently tile drained and fertilized with phosphate to optimize plant growth. Phosphate is often lost from fields via surface runoff and tile drainage, either with particulate soil matter or as dissolved reactive phosphate. Soil health, aided by enzymes produced by microorganisms and plants, can influence the retention and loss of phosphate. Stable oxygen isotopes may provide a non-invasive way of measuring the biological turnover rate of phosphate in soils over longer time scales than previous methods. The ability of oxygen isotopes in phosphate to measure biological turnover was examined in a study with three fields in the Maumee River watershed from fall 2016-summer 2017. Samples were collected after fall tilling and fertilization, and before and after spring planting and fertilization. Soil nutrients and metal concentrations were analyzed as well as oxygen isotope analysis from soil phosphate, soil pore-water, and tile water. Overall, sites had high nutrient and metal concentrations and low levels of phosphate recycling relative to the overall pool of phosphate, based on oxygen isotope analysis. Soil samples did not reach equilibrium with soil pore-water. The most recycled sample collected, a tile drain sample collected five months after fall fertilization, was still about 80% fertilizer. The results suggest that sources of phosphate can be detected for long periods of time in agricultural fields under specific circumstances and that phosphate ion interactions with metal oxides may help explain the lack of equilibrium observed. Oxygen isotope studies of phosphate in soil could help researchers and field managers better understand the mechanisms behind the effects of various best management practices (BMPs) on nutrient runoff.

Committee: Kevin McCluney Ph.D. (Advisor); Shannon Pelini Ph.D. (Committee Member); Angelica Vázquez-Ortega Ph.D. (Committee Member) Subjects: Agriculture; Biogeochemistry; Ecology; Environmental Science; Soil Sciences

Master of Science, University of Toledo, 2020, Mechanical Engineering

Synthetic bone cements have been used as organic graft substitutes for since the early 20th century for multiple surgical procedures including orthopedic and dental applications. Ceramic bone cement can primarily consist of phosphate, magnesium, and calcium which are all completely biocompatible and have exceptional properties for bone growth. However, a few main issues with phosphate-based cements includes their poor mechanical and physical qualities such as compressive strength, crack propagation, injectability, and cell culturing. This limits the uses of the cement to non-load bearing bone filler. The other issue is the potential for phase separation during injection in surgery. This causes the liquid component of the cement to be filter pressed through the powder component, and making the cement not set and deteriorate before bone regeneration. However, this would be unacceptable for clinical use. Recent studies have shown that these properties can be better developed through the incorporation additives like fiber reinforcements and retarders, increasing the liquid to powder ratio (LPR), decreasing the particle size, and selecting an efficient syringe. These strategies were used to improve the injectability of the both calcium phosphate cement (CPC) and magnesium phosphate cement (MPC) while maintain the mechanical and biological properties. In the first study the CPC's LPR was increased to 0.4, their powder particle sizes were decreased to less than 90 μm, and a suitable amount of citric acid was added as a retarder. Also, in some of the composition of CPC newberyite (NB), a reinforcement platelet particle, was added in different amounts to test the strength of the cement. In the second study MPC's LPR was increased to 0.4, their powder particle sizes were decreased to less than 45 μm, and a suitable amount of boric acid was added as a retarder. All components of both the CPC and MPC have good biological properties and many papers have shown that changing these (open full item for complete abstract)

Committee: Sarit Bhaduri (Committee Chair); Matthew Franchetti (Committee Member); Vijay Goel (Committee Member) Subjects: Biomedical Engineering

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

Bioimplant is a group of medical devices that aim to restore/replace the function of the defected/diseased tissue. As the potential candidate for orthopedic applications, the implant material needs to maintain the suitable mechanical properties and desirable surface chemistry to ensure long-term mechanical stability and foster the regeneration of host tissue at the defect site. Due to the advancement in the research of biomaterials, a wide range of materials including metals, ceramics, polymers, and composites now can be used in bone grafting procedure for different purposes. However, none of the currently available bioimplant materials have met all the requirements and expectations. For instance, most of the metallic implant materials with high strength present poor osseointegration properties. Hence, there have been great efforts in developing the alkaline earth phosphate based bioactive coatings on implant materials to promote bone mineralization. This study covers diverse types of surface modifications of metallic implant material – magnesium alloy and polymeric implant material – polyetheretherketone (PEEK) with various alkaline earth phosphate coatings, nanostructuring, composite formation and surface pretreatments. In the first part of this thesis, a microwave assisted coating technique was developed to improve in vitro degradation behavior and biological properties of Mg alloys. The microwave irradiation dramatically accelerated coating deposition kinetics and notably shortened the coating process to minutes rather than hours/days consumed in the conventional biomimetic coating method. Moreover, the as-deposited calcium deficient hydroxyapatite (CDHA) and magnesium phosphate (MgP) layers presented outstanding corrosion resistance and bioactivity in physiological environment, which evidently enhanced the biological responses of Mg alloys. Further on, organic-inorganic composite coatings were synthesized by combining the microwave assisted coating techniq (open full item for complete abstract)

Committee: Sarit Bhaduri (Committee Chair); Vijay Goel (Committee Member); Arunan Nadarajah (Committee Member); Ahalapitiya Jayatissa (Committee Member); Matthew Franchetti (Committee Member) Subjects: Materials Science; Mechanical Engineering

Master of Science in Chemical Engineering, Cleveland State University, 2016, Washkewicz College of Engineering

Digestate (D), the remaining substance after anaerobic digestion of a biodegradable feedstock, is rich in inorganic contents, which makes it a good candidate for growing algae for biofuel production. Previous studies showed digestate at around 1.25% to 1.75% (v/v) dilution is suitable for algae growth. In this study, magnesium sulfate (MgSO4) and dipotassium hydrogen phosphate/potassium dihydrogen phosphate (K-P) were added to diluted digestate growth media. Two sets of experiments were conducted in batch reactor mode to identify the digestate (D), magnesium sulfate (MgSO4) and dipotassium hydrogen phosphate/potassium dihydrogen phosphate (K-P) concentrations that would optimize the algae growth. Algae growth parameters, such as maximum growth rate (r) and maximum algae concentration (Xmax) were estimated by using non-linear regression with a four-parameter logistic equation. Average biomass productivity (Pa), instantaneous biomass productivity (Pi), and specific growth rate (ug) were also calculated. This study used a central composite design. A surface response regression equation was generated for each of these algae growth parameters; the equation contained linear terms, quadratic terms, and the first order interaction terms of the three factors (D, MgSO4, and K-P). The resulting regression models showed both the maximum growth rate and the maximum algae concentrations were mainly dependent on digestate. The highest maximum growth rate was obtained at around 1% (v/v) digestate dilution. Within the tested digestate dilutions (0.184 to 1.817% (v/v)), maximum algae concentration increases with digestate concentration. In addition, the data and analysis showed that digestate concentration of 1.4% (v/v) dilution and low K-P and MgSO4 concentrations would be expected to result in high average biomass productivity and instantaneous biomass productivity. The digestate concentrations does not alter the effects of K-P and MgSO4 on algae growth, but an interact (open full item for complete abstract)

Committee: Joanne Belovich Ph.D. (Advisor); Jorge Gatica Ph.D. (Committee Member); Moo-Yeal Lee Ph.D. (Committee Member) Subjects: Chemical Engineering

Master of Sciences, Case Western Reserve University, 2016, Biology

G6PDd has long been associated with malaria endemic regions and is believed to serve as protection from severe malaria. Simultaneously, G6PDd also has serious implications in the treatment of Pv hypnozoites as the only drug approved by the WHO, Primaquine, can cause severe hemolytic anemia in G6PDd individuals. Little research has been done to understand G6PDd genotype or phenotype in Madagascar and how this affects the treatment for Pv in infected individuals, resulting in a gap in knowledge. To fill this gap, a standard Point of Care assay was optimized for use in the field and compared to the complete G6PD gene sequence to begin understanding the concordance between genotype and phenotype. Using complete G6PD gene sequences and population-targeted genotyping techniques, there were four documented exonic single nucleotide polymorphisms associated with African, Mediterranean, and Asian origin, no novel were polymorphisms present, and phenotype concordance within five identified haplotypes was performed.

Committee: Peter Zimmerman PhD (Advisor); Emmitt Jolly PhD (Committee Member); Daniel Tisch PhD (Committee Member) Subjects: Genetics

MS, University of Cincinnati, 2015, Engineering and Applied Science: Environmental Engineering

Phosphate, as an essential and often limiting nutrient in most aquatic ecosystems, can result in the acceleration of eutrophication; leading to increased water treatment costs, decreased recreational value, and the formation of harmful algal blooms which may pose a risk to human health due to the production of cyanotoxins. Though while viewed as a pollutant in certain scenarios, the demand of phosphate for industrial purposes is increasing; yet reserves are quickly being diminished. Therefore, the remediation and recovery of phosphate is a growing concern. One process which can both remove and recover phosphate is adsorption. Metal oxides like the iron oxide goethite have long been known to adsorb anions like phosphate, and some companies have developed commercially available, goethite-based adsorbents. This study explored the surface modification of one of these commercially available adsorbents, Bayoxide ® E33, using either manganese or silver nanoparticles to coat the solid surface to enhance the capacity of phosphate adsorption. After the synthesis of modified adsorbents, the samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high resolution-TEM (HR-TEM), and BET surface area and zeta potential analyzers to gain insight on physical and chemical characteristics of the adsorbents. To study phosphate adsorption onto these surfaces, batch and column studies were conducted using lake water. Batch studies were carried out to explore both adsorption equilibrium and kinetic parameters. These results were modeled using several models (e.g. the Langmuir isotherm model and the pseudo-second-order model) to gain further insights into the adsorbents equilibrium and kinetics of adsorption. The Langmuir isotherm model, for example, indicate that one of the surface modified adsorbents (E33/AgII) had a slightly higher maximum amount of adsorbate remo (open full item for complete abstract)

Committee: Dionysios Dionysiou Ph.D. (Committee Chair); Mallikarjuna Nadagouda Ph.D. (Committee Member); George Sorial Ph.D. (Committee Member) Subjects: Environmental Engineering

Doctor of Philosophy, University of Toledo, 2014, Bioengineering

The focus of this dissertation is synthesis and biomedical applications of magnesium phosphate nanoparticles. Phosphates of alkaline earths such as calcium phosphates (CaPs; also synonymously referred to as apatites) have long been known as biocompatible orthopedic substituents. Like calcium, magnesium belongs to the alkaline earths. However, magnesium phosphates (MgPs) are not as well studied as the CaPs even though they are effective scaffold materials and potential nonviral DNA carriers. Hence, it is important to investigate MgPs in depth. Relatively open structures of apatites provide them with possibilities for various substitutions. Present research focuses on the applications of magnesium phosphate nanoparticles as promising biomaterials with a focus towards orthopedic uses. The relevance of these apatite nanoparticles in biomedical applications depends on the efficiency and speed of the synthesis process as well as the biocompatibility since the ease of production method and lack of cytotoxicity are some of the most crucial factors for mass production of biomaterials. Consequently, as explained below, the goal of this study is to provide an efficient production method for these apatites via a novel microwave assisted synthesis method (MAS), investigate their bioactivity, and examine their applications as scaffolds in orthopedics, and carriers in gene delivery. Amorphous magnesium phosphate nanoparticles were synthesized utilizing a novel, and rapid microwave assisted synthesis (MAS) method. In this methods, the household microwave generated rapid heating and cooling to promote generation of nanoparticles. The ability to control the heating time and power, and speed are some advantages of the applied methods for quick production of nanoparticles of interest. The as-synthesized materials were characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (open full item for complete abstract)

Committee: Sarit B. Bhaduri (Committee Chair) Subjects: Biomedical Engineering

MS, University of Cincinnati, 2012, Medicine: Industrial Hygiene (Environmental Health)

The U.S. is a leading producer of phosphate rock for processing, with a large portion of mining and production occurring in central Florida. Florida phosphate mining and beneficiation operations currently provide about 75% of the national supply of phosphate- based fertilizers and 25% of the world supply. This constitutes a multi-billion dollar economic investment in the state with over 6000 jobs provided directly by the industry and as many as 30,000 additional positions in transport, shipping, and other service industries. Potential occupational exposures associated with phosphate mining and beneficiation include sulfuric and phosphoric acid mists2, other mists and dusts containing phosphate, ammonium, fluoride, respirable silica, and technically enhanced naturally occurring radioactive materials (TENORM) 3. While the possible association between phosphate mining and beneficiation and excesses in cancers, specifically lung cancer and leukemia, has been studied, job exposure metrics have not been included. The goal of this study was to produce a job exposure matrix (JEM) based on exposure data (collected at four central Florida Phosphate fertilizer plants and one ore mining and beneficiation plant), positions held, regulatory and process changes, and the implementation and use of engineering controls and PPE. Because of limited exposure data, many of these factors could not be investigated. The resulting JEM was constructed based on job titles found in company records and cross referenced with industry job descriptions for assignment to similar exposure groups. These groups were then assigned a qualitative exposure rating based on data comparisons of two industrial hygiene surveys conducted in the Florida phosphate fertilizer industry. The JEM will be used by NIOSH researchers to reexamine the cohort of phosphate workers originally assembled by Stayner et al. 1

Committee: Carol Rice PhD (Committee Chair); Travis Kubale PhD (Committee Member); Paul Succop PhD (Committee Member) Subjects: Environmental Health

Master of Science in Biomedical Sciences (MSBS), University of Toledo, 2011, College of Medicine

Brain ischemia induces a metabolic insult that disrupts normal neuronal transmission and leads to a prolonged hyperexcitable state. As a result of increased hyperexcitability, the brain may fire hypersychronous electrical discharges known as seizures. Seizures which become self-sustaining for 30 min or more, called status epilepticus (SE) are highly indicative of a poor prognosis. Thus, identifying how low oxygen and/or low glucose contribute to the generation of seizures may unveil mechanisms related to epileptogenesis, as well as provide a therapeutic target. Often, an imbalance in excitatory and inhibitory neurotransmission is associated with seizure development, which primarily involves glutamate and γ-aminobutyric acid (GABA) neurotransmission, respectively. GABARs are known for mediating the majority of fast inhibitory neurotransmission in the brain and play an integral role in the development of seizures. While GABARs are well-known for mediating anticonvulsant effects, their dysfunction during the development of seizures remains unclear. The lack of oxygen and/or low glucose may alter inhibition in the brain leading to an increased hyperexcitable state. In this thesis, we created a model of mild-to-moderate hypoxia/hypoglycemia that would allow investigation into the differential effects of hypoxia, hypoglycemia, or the combination on GABARs in the in vivo setting. We found that seizures were readily induced in rats when moderate doses of insulin were combined with or without oxygen. Rats treated with insulin alone (5U/kg) exhibited lethargy and developed myoclonic jerks, barrel rotations, and tonic-clonic seizures. No seizure activity was observed in rats treated with hypoxia (10% FiO2). Pulse oximetry data showed that rats treated with insulin had a decreased heart rate, while hypoxia and hypoxia/hypoglycemia treated rats displayed a decrease in peripheral oxygen saturation (SPO2). Future studies will be directed at assessing the differential effects of lo (open full item for complete abstract)

Committee: L. John Greenfield MD/PhD (Committee Chair); Nicolas Chiaia PhD (Committee Member); Marthe Howard PhD (Committee Member); Joseph Margiotta PhD (Committee Member); Bryan Yamamoto PhD (Committee Member) Subjects: Biomedical Research; Neurosciences

Master of Science, University of Akron, 2008, Chemistry

The synthesis of new phenylhydroxyiodonium phosphates from (diacetoxyiodo) benzene and dialkyl phosphates, and their use in the phosphorylation of ketones was investigated. Reaction of diphenyl phosphate, (PhO)2P(O)OH, with (diacetoxyiodo) benzene, PhI(OAc)2, in the presence of water gave [hydroxy((bis(phenyl)phosphoryl)oxy)iodo] benzene, (PhI(OH)OPO(OPh)2, HPIB) as a white solid in excellent yield. Similarly prepared are PhI(OH)OPO(OCH3)2, PhI(OH)OPO (OCH2CH3)2, PhI(OH)OPO(OCH2CH2Cl)2, PhI(OH)OPO(OCH2CCl3)2, and PhI(OH)OPO(OCH2CF3)2 from the corresponding monobasic acid phosphates (RO)2P(O)OH (R= CH3, CH3CH2, CH2ClCH2, CCl3CH2, and CF3CH2) in 77-93 % yield. These ketones (acetophenone, 4-methoxyacetophenone, p-nitroacetophenone, acetone, and pinacolone) were directly phosphorylated at the carbon with the iodine (III) reagent, HPIB, or its alkyl derivatives to give the corresponding phosphoryloxy derivatives in 41-89 % yield.

Committee: Kim Calvo (Advisor) Subjects: Chemistry, Organic

Doctor of Philosophy in Engineering, University of Toledo, 2011, Biomedical Engineering

Calcium phosphate materials (CaP) are known to be major constituents of mammalian bone and synthetic CaPs have been shown to be bioactive in vitro and in vivo. They are one of the most versatile biomaterials for orthopedic applications and have been shown to be effective scaffolds for bone regeneration and as gene delivery carriers. However, significant problems related to their synthesis have limited their clinical use. Conventional processing produces CaP with low crystallinity and large particulates which contributes to the overall brittleness of formed products. This has largely restricted the use of synthetic CaPs to non load-bearing applications. Nanopowders can be used to produce products with smaller grain sizes and thus improved mechanical properties. Traditional CaP transfection often results in the formation of large aggregates due to subsequent crystal growth. As such, synthesis of nano CaPs is of particular interest and importance in developing novel therapeutic strategies for orthopedic pathologies. Calcium phosphate nanoparticles (CaPn) were synthesized utilizing two different methods—chemical precipitation and a microwave assisted combustion synthesis (MACS) method. Microwave processing has been shown to homogenize the heating profiles of materials via bulk or volumetric heating, as well as reduce processing times. This results in more uniform particle formation and products with improved integrity. The precipitated CaPn were sintered via microwave heating while those produced with MACS required no further heat treatment. The as-synthesized materials were characterized using FTIR, XRD, SEM and TEM. In vitro results using mouse osteoblasts on microwaved scaffolds showed cell growth over a seven day time period, demonstrating the biocompatibility of the microwave samples. The CaPn generated from MACS were highly nanocrystalline and had high aspect ratios. They were studied as possible nonviral gene delivery carriers. A hydroxyapatite variant with europ (open full item for complete abstract)

Committee: Sarit Bhaduri PhD (Committee Chair); Kathryn Eisenmann PhD (Committee Member); Joseph Lawrence PhD (Committee Member); Beata Lecka-Czernik PhD (Committee Member); Scott Molitor PhD (Committee Member); Stephen Callaway PhD (Committee Member) Subjects: Biochemistry; Biomedical Engineering; Biophysics; Nanoscience

Doctor of Philosophy, The Ohio State University, 2024, Microbiology

Bacteria can communicate with each other through the production, release, and detection of small molecules called N-acyl homoserine lactones (AHLs). In a subset of the family Enterobacteriaceae, including the well-known genera Salmonella and Escherichia, AHLs are not produced but these bacteria retain the ability to detect them through the LuxR-type protein SdiA. This strategy is referred to as eavesdropping: where one species may listen in on the communication of another. The role of SdiA-mediated eavesdropping in the lifecycle of these bacteria is unknown. To determine the function of eavesdropping, we first reviewed the available literature on SdiA. Since the initial discovery of SdiA, many studies have attempted to gain insight into its role by looking for mutant defects in various host systems, elucidating the SdiA regulon, or finding in vitro phenotypes. The literature on each topic is complex and interpretation must be measured and considerate of the methodology used. We next examined the role of Salmonella SdiA in several host systems, including house flies, mice, and plants. We also determined the SdiA regulons of Salmonella, E. coli, and Enterobacter cloacae. The house fly is a known mechanical vector of Salmonella with some evidence of a more dynamic interaction between host and bacteria. Based on the abundance of AHL synthase homologs in insect metagenomes, we hypothesized that SdiA played a role in the survival of Salmonella within house flies. After a series of experimental infections, the evidence suggests that sdiA mutants are highly advantaged over their wild-type competitor and that SdiA may have a negative effect on survival within house flies. Using a randomly barcoded transposon library (Barseq), we examined Salmonella fitness in mice that were co-infected with the AHL producing pathogen Yersinia enterocolitica. Consistent with previous reporting, sdiA and its regulon suffered no fitness defects during gastroenteritis. Finally, an experiment (open full item for complete abstract)

Committee: Brian Ahmer (Advisor); Chad Rappleye (Committee Member); Sarah Short (Committee Member); John Gunn (Committee Member) Subjects: Microbiology

Master of Science, The Ohio State University, 2006, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 1920, Graduate School

Committee: Not Provided (Other) Subjects:

Doctor of Philosophy, University of Akron, 2023, Chemical Engineering

Wastewater stemming from both residential and industrial sources commonly contains notable quantities of ammonium (N) and phosphate (P). Elevated levels of N and P within wastewater can give rise to significant challenges for aquatic ecosystems and wildlife. Meanwhile, it is crucial to recognize that N and P are valuable resources with diverse applications. This dual role of N and P, both as potential environmental pollutants and indispensable resources, underscores the need for efficient and sustainable approaches to manage and recover these nutrients from wastewater. The initial facet of this study delves into the utilization of the redox flow deionization cell (RFDC) as a new alternative approach for the elimination of N and P from wastewater. RFDC boasts commendable attributes, including heightened energy efficiency, continuous operational capabilities, and concurrent deionization within the ion's removal channel, coupled with ion concentration within the concentrated channel. The investigation of RFDC performance was conducted, taking into consideration the influence of wastewater concentration and applied cell voltage. This encompassed an appraisal of parameters such as the average salt removal rate, ion removal efficiency, and electrical energy consumption, including both N and P removal experiments. Additionally, the impact of coexisting ions, namely sodium cations (Na+) and chloride anions (Cl-), on N and P removal efficacy was subject to examination. The findings of this study underscore the expeditious removal of N and P within the ion's removal channel, coinciding with the concurrent concentration of ions within the concentrated channel. Intriguingly, it emerges that N exhibits a heightened selectivity in contrast to the coexisting cation (Na+), while P exhibits considerably diminished selectivity when juxtaposed with the coexisting anion (Cl-). This observation manifests in augmented electrical energy consumption attributable to the concomitant rem (open full item for complete abstract)

Committee: Zhenmeng Peng (Advisor); Ping Yi (Committee Member); Qixin Zhou (Committee Member); Bi-min Zhang Newby (Committee Member); Lingxing Yao (Committee Member) Subjects: Chemical Engineering; Chemistry; Environmental Engineering; Sustainability

Doctor of Philosophy, The Ohio State University, 2023, Mechanical Engineering

Lithium-ion (Li-ion) batteries adopted in electric vehicles (EVs) require significant increase in energy density (> 750 Wh/L) and reduction of costs to enable widespread commercialization. To address these challenges, R&D efforts have been directed towards (a) finding materials with high energy density (b) improving electrode design and (c) enhancing conductivity of the electrode materials. The former strategy involves implementing Nickel and Manganese based chemistries such as NMC, LNMO. In particular, the LNMO spinel cathode material is a promising material which provides high energy densities of 650 Wh/kg due to increased operating voltage of 4.75 Vvs Li/Li+. However, the increased voltage also accelerates oxidative decomposition reactions in the electrolyte and causes capacity fade in LNMO full cells paired with graphite anode. Using a composite binder can help passivate the carbon and cathode material surfaces against decomposition products from the electrolyte. Further, the composite binder also has the advantage of using water as the solvent making the process environmentally benign and cheaper compared with currently adopted N-Methyl 2-Pyrrolidone (NMP) solvent. The second strategy includes minimizing the use of inactive materials (e.g., current collectors and separators) and increasing the thickness of electrodes (> 250 µm), which in turn offers improved energy density with reduced cost. To achieve this an aqueous composite binder system is utilized which can sustain high thickness of electrodes while creating unique electrode architectures conducive to ionic and electronic conductivity. The third strategy utilizes a conductive polymer additive to create ion and electron conducting interfaces across the cathode material surface thereby providing better cycle and rate performance. The performance improvement in each of these strategies is demonstrated through electrochemical tests and their mechanisms are understood by utilizing several characterization tec (open full item for complete abstract)

Committee: Jung Hyun Kim (Advisor); Jay Sayre (Committee Member); Hanna Cho (Committee Member); Christopher Brooks (Committee Member) Subjects: Automotive Engineering; Automotive Materials; Materials Science; Mechanical Engineering

Master of Science in Materials Science and Engineering (MSMSE), Wright State University, 2023, Materials Science and Engineering

High concentrations of phosphate are known to adversely affect the environment. Excess phosphate can lead to eutrophication that eventually fosters uncontrollable growth of aquatic plants and algae. This can result in depletion of oxygen content which adversely impacts underwater organism's survival rates. Metal organic frameworks (MOFs) consist of organic linkers in conjunction with metal ions or clusters arranged within a crystalline structure. They are highly porous and have larger surface area due to their ability to possess extensive void spaces while remaining bulky in nature. MOFs can absorb phosphate from aqueous solutions. We have investigated the use of commercially available MOFs to extract phosphate. In this project, activated carbon was utilized as a control sample to compare the adsorption capacity of Metal-Organic Frameworks (MOFs), specifically evaluating Basolite C300, Basolite Z1200, Basolite A100, Basolite F300 and Basolite Z377. Three different pH solutions such as 5, 7, and 9 were used to study the influence of pH in adsorption. The scope of research encompasses both kinetics and Freundlich isotherm assessments. Scanning Electron Microscopy (SEM), Elemental Dispersive X-Ray Analysis (EDAX) and X-Ray Diffraction (XRD) techniques employed to study the MOFs in both pre- and post-adsorption analyses. It was found that some of the MOFs have better adsorption capacity when compared to other adsorbents.

Committee: Henry D. Young Ph.D. (Advisor); Malikarjuna N. Nadagouda Ph.D. (Committee Member); Hong Huang Ph.D. (Committee Member) Subjects: Materials Science

Doctor of Philosophy, The Ohio State University, 2023, Biomedical Sciences

Antibiotic resistance is an urgent public health problem and is associated each year with over a million deaths worldwide. Strategies to limit antibiotic exposures as well as improved practices for infection prevention and containment have been successful in reducing the emergence and spread of antibiotic resistance. Despite these efforts, novel therapeutic strategies are needed. In this dissertation, we investigate the induction of sugar-phosphate toxicities as a novel therapeutic modality to selectively target microbial pathogens. We use Salmonella enterica serovar Typhimurium, as our model pathogen, due to its clinical relevance, tractable genetics, and well-developed mouse models for studying infection. It is also one of the most characterized microbes and many aspects of its physiology and pathogenesis are relevant to other pathogens of the Enterobacteriaceae family for which antibiotic resistance is of paramount concern [i.e., the Carbapenem-resistant Enterobacteriaceae (CRE) and extended spectrum beta-lactamase (ESBL)-producing pathogens]. Here, we have assembled and characterized a collection of Salmonella mutants predicted to suffer sugar-phosphate toxicity due to the absence of targeted enzymes within a variety of sugar-utilization pathways. Elimination of these enzymes coupled with the provision of the appropriate sugar leads to the accumulation of toxic sugar-phosphate intermediates resulting in growth inhibition. These mutations serve as a proxy for small molecule inhibitors of those enzymes that would be used in real-world therapeutic applications. Of the seven mutants tested in vitro, five (galE, galT, rhaD, mtlD, and araD) mutants showed growth inhibition in addition to a fraB mutant reported in earlier work. All but the galT mutant were also attenuated in a mouse model of Salmonella-mediated gastroenteritis. While homologs of galE are widespread among bacteria and in humans, the araD, mtlD, rhaD, and fraB genes are rare in most phyla of bacteria a (open full item for complete abstract)

Committee: Brian Ahmer Ph.D. (Advisor); Venkat Gopalan Ph.D. (Committee Member); Vanessa Hale DVM, MAT, Ph.D. (Committee Member); John Gunn Ph.D (Committee Member) Subjects: Biomedical Research; Microbiology; Molecular Biology

Master of Science (M.S.), University of Dayton, 2022, Electro-Optics

Large electro-optic crystals can suffer from an undesired piezo-electric ringing effect, which can significantly reduce the on-off contrast ratio for the modulator. First, the applied voltage across the electro-optic crystal excites acoustic modes of the crystal through the elasto-optic effect. The shape and frequency of these stress waves are related to the geometry of the crystal. The complex stress patterns, in turn, affect the optical response of the EO crystal due to the piezo-electric effect, making the performance of electro-optic modulators difficult to simulate and model. This work proposes a way to model these complex couplings using common finite element analysis and beam propagation techniques. The piezo-electric ringing of a deuterated potassium dihydrogen phosphate crystal is simulated and the results are compared to experimental observations. Finally, this work simulates a scenario which mitigates this undesirable elasto-optic effect in this material, and proposes methods of mitigating this effect for other electro-optic crystals.

Committee: Partha Banerjee (Advisor); Swapnajit Chakravarty (Committee Member); Rudra Gnawali (Committee Member) Subjects: Optics

Master of Science (MS), Bowling Green State University, 2022, Geology

The Western Lake Erie Basin (WLEB) has been experiencing harmful algal blooms due to increases in dissolved reactive phosphorous (DRP) from agricultural land in the Maumee River watershed. Agricultural best management practices (BMPs) can be useful to mitigate the DRP loads; nevertheless, DRP is not always fully removed by in-field BMPs. Phosphorous (P) removal structures can be filled with phosphorus sorption materials (PSM) such as iron and aluminum oxides and can be placed at the junction of runoff and subsurface drainage to trap DRP from tile drainage. However, dissolved organic matter (DOM) from the agricultural farmland might compete with phosphate ions (PO43-) at the adsorption sites in the media, reducing its lifetime and efficiency. Therefore, laboratory flow-through column experiments were conducted to determine whether DOM is affecting P sorption onto iron enhanced activated alumina media (Alcan). The experiments were informed by field data collected from a regional farm. Alcan (Al/ Fe (hydro) oxides) media was efficient in removing PO43- coming into the filtering system and thereby, flow-through column experiments were able to determine a discrete P removal percentage efficiency of 83.32%, 68.26%, 66.54%, 57.16% and 41.27% by the end of treatment I (5mg L-1 PO43- only), treatment II (5mg L-1 PO43- and 5 mg L-1 DOM), treatment III (5mg L-1 PO43- and 10 mg L-1 DOM), treatment IV (5mg L-1 PO43- and 20 mg L-1 DOM), and treatment V (10mg L-1 PO43- and 20 mg L-1 DOM), respectively. Moreover, from exponential regression analysis of P removal curves for each treatment, it was measured that a total cumulative of 231.45 gm, 92.65 gm, 92.06 gm, 65.998 gm and 91.476 gm of P per kg PSM can be added to treatment I, II, III, IV and V, respectively, until the media gets fully saturated, i.e., concentration of influent PO43- would be equal to the effluent PO43- concentrations. It is evident that DOM is competing with PO43- decreasing PO43- sorption onto the Alcan media. (open full item for complete abstract)

Committee: Angélica Vázquez-Ortega PhD (Committee Chair); Enrique Gomezdelcampo PhD (Committee Member); Margaret (Peg) M. Yacobucci PhD (Committee Member) Subjects: Environmental Geology; Environmental Science; Environmental Studies; Geochemistry; Geology; Soil Sciences