PhD, University of Cincinnati, 2024, Medicine: Biomedical Informatics

B cell receptor (BCR) repertoire constitutes the diverse range of BCRs expressed by an individual's total B cell population. B cells are responsible for a humoral immune response by producing antibodies against foreign antigens. Computational analysis methods to understand the diverse immune repertoire and its response to diseases are rapidly evolving. These analysis methods reveal the underlying mechanisms for healthy individuals and various diseases. These methods depend on the choice of the analysis tools used for annotation of antibody gene sequences. In this dissertation, I describe a comprehensive benchmarking of three commonly used antibody gene sequence annotation tools and the construction of an ensemble annotation method. Without any ground truth dataset that can be used for comparison, we developed a set of consensus sequences as our silver standard which are simulated for somatic hypermutations and their performance fall-off calculated. In the second part of my dissertation, I develop analysis methods that measure quantitative features of the B cell receptor repertoire. I then apply these analysis methods to study allergic food sensitization in children with atopic dermatitis. I propose a novel score, which we name the Immune Repertoire in Atopic Disease (IRAD) score, that could be used to measure the severity of AD and aid in disease diagnosis and risk stratification.

Committee: Krishna Roskin PhD (Committee Chair); Paul Spearman M.D. (Committee Member); Jaroslaw Meller Ph.D. (Committee Member); Sandra Andorf Ph.D. (Committee Member) Subjects: Bioinformatics

PhD, University of Cincinnati, 2023, Engineering and Applied Science: Materials Science

As super-saturated solid solutions of Al-Mg, 5XXX series aluminum alloys are susceptible to sensitization via intergranular precipitation of the anodic ß-phase, which promotes intergranular corrosion, exfoliation and stress corrosion cracking under environmental conditions. This deleterious process occurs at time and temperature scales that eventually impact most structural applications over the course of multiple decades. Efforts to better control sensitization in these alloys, or establish predictive models, have historically been hampered by the large inter-lot variations found between nominally identical material produced by different suppliers, as the starting microstructure and total rolling reduction are not adequately specified by current cold-rolled plate tempers. The work in this dissertation demonstrates that the sensitization response of these alloys can be approached as a combination of two independent contributions: the geometric configuration of grain boundaries passing through the microstructure that are most prone to sensitization, and the rate that these boundaries sensitize due to the formation of the ß-phase. The sensitization rate kinetics of the most susceptible boundaries can be modeled using a modified Johnson-Mehl-Avarami-Kolmogorov (JMAK) theory based approach, as applied to the impinging locally sensitized regions surrounding discrete ß-phase precipitates. The microstructural configuration manifests as a sample-dependent linear scaling factor in the sensitization response. The JMAK model describes the kinetics of sensitization with excellent accuracy across all data available in the literature. This work demonstrates through the JMAK sensitization model that a clear change in the ß-phase nucleation and growth kinetics in these alloys can be observed above 100°C, and the kinetic constants both above and below that temperature can be accurately fitted. The results of the model importantly imply that sensitization at environmental temp (open full item for complete abstract)

Committee: Matthew Steiner Ph.D. (Committee Chair); Sarah Watzman Ph.D. (Committee Member); Ashley Paz y Puente Ph.D. (Committee Member); Dinc Erdeniz Ph.D. (Committee Member) Subjects: Materials Science

Master of Science (MS), Wright State University, 2023, Anatomy

Early-life stress appears to sensitize neuroinflammatory signaling to increase later vulnerability for stress-related mental disorders. How stress initiates this process is unknown, but sympathetic nervous system activation during the early stress may be key. Isolated guinea pig pups display inflammatory-mediated depressive-like behavior and fever that sensitize on repeated isolation. We assessed whether sympathetic nervous system activity contributed to the sensitization process in guinea pig pups. In Experiment 1, the adrenergic agonist ephedrine, either alone or with cortisol, did not increase depressive-like behavior or fever during an initial isolation the following day. In Experiment 2, both depressive-like behavior and fever sensitized with repeated isolation, but beta-adrenergic receptor blockade with propranolol did not affect either of these responses or their sensitization. Results suggest sympathetic nervous system activation is neither necessary nor sufficient to induce the increased neuroinflammatory signaling underlying sensitization of depressive-like behavioral or febrile responses in developing guinea pigs.

Committee: Michael B. Hennessy Ph.D. (Advisor); Michal J. Kraszpulski Ph.D. (Committee Member); Patricia A. Schiml Ph.D. (Committee Member) Subjects: Behavioral Psychology; Behavioral Sciences; Developmental Psychology

Doctor of Philosophy, The Ohio State University, 2021, Chemistry

The global need for clean renewable fuels has led to a high degree of interest in using photocatalytic processes that can form useful fuels. Semiconducting metal oxide materials have been extensively studied in this field due to their ability to generate highly reactive charge carriers upon photoexcitation, nontoxicity, and inexpensive fabrication. CeO2 has recently garnered interest as a photocatalytic material due to its redox mutability and relative abundance. In order to understand and improve the behavior of CeO2 as a photocatalyst, a thorough investigation into the dynamics of photoexcited charge carriers is needed. Herein, transient absorption spectroscopy was used to study the lifetime of photogenerated electrons and holes within CeO2 nanoparticles with varying diameters and crystalline domain sizes. Through tuning the size, the surface-to-bulk ratio is altered, allowing for a finer study of the surface and bulk hole dynamics in the nanoparticles. Through hole scavenging experiments, spectral assignments of surface and bulk holes were made and the behavior of these carriers vs electron small polarons (self-trapped electrons) was compared. The faster decay dynamics of ESPs in comparison with hole dynamics, both bulk and surface, reveals that the latter charge carrier is able to migrate away from its geminate partner and likely trap elsewhere within the particle. This observation suggests CeO2 nanoparticles should be considered photocatalysts for oxidation half reactions in which holes are employed. The surface holes were found to decay slower than the bulk holes, indicating that the latter trap/recombine more quickly. This long-lived decay for surface holes shows promise for the use of CeO2 as a photocatalytic oxidant. Signals from both holes and electrons small polarons decay slower in larger nanoparticles comprised of larger crystalline domains. This observation suggests the larger distance the electron small polaron must migrate or “hop” to within CeO2 a (open full item for complete abstract)

Committee: Bern Kohler (Advisor); Heather Allen (Committee Member); Robert Baker (Committee Member) Subjects: Chemistry; Materials Science

Doctor of Philosophy, The Ohio State University, 2021, Neuroscience Graduate Studies Program

Chronic stress is a major factor in anxiogenesis that has been attributed to the activation and prolonged elevation of maladaptive immune signaling in the CNS and the periphery. A primary response to stress in the murine model for psychosocial stress, social defeat, consists of the activation of brain microglia and their subsequent recruitment of peripheral monocytes to the cerebral vasculature. Both microglia and monocytes are active producers for inflammatory cytokine IL-1b and other inflammatory mediators. Although there have been myriad studies that showed the importance for IL-1 signaling in the CNS for psychosocial stress and its deleterious behavioral responses, only recently have we developed more powerful tools that allow for discovery of the specific cell-type responses to this cytokine that drive anxiety-like behavior. As such, we first sought to examine the role for the primary IL-1b receptor, IL-1R1, and to determine which cell type in the brain is the primary responder to microglial and macrophage IL-1b (Chapter 2). Social defeat induced generalized social withdrawal, as demonstrated by reductions in social interactivity with juvenile mice, and cognitive deficits as measured by a working memory task. Global knockout of IL-1R1 (IL-1R1-/- mice) prevented these stress-induced behavioral deficits, as well as stress-associated monocyte trafficking to the brain, microglia activation, and elevated cytokine levels. We subsequently discovered that the neuronal IL-1 receptor (nIL-1R1) was the primary driver for these behavioral deficits, and that the IL-1R1+ neurons localized in the hippocampus were able to have direct effects on behavior after stress. Since microglia are both direct and indirect sources for IL-1b in the CNS, we examined the effects of microglial depletion via CSF1R antagonist PLX5622 on the other major cell types of the hippocampus after social defeat (Chapter 3). We employed single-cell RNA-sequencing to determine per-cell alterations in the t (open full item for complete abstract)

Committee: Jonathan Godbout PhD (Advisor); Ning Quan PhD (Advisor); John Sheridan PhD (Committee Member); Tamar Gur MD, PhD (Committee Member) Subjects: Immunology; Neurosciences

Master of Science, The Ohio State University, 2021, Materials Science and Engineering

Aluminum-magnesium 5xxx series alloys are utilized in marine applications due to good weldability and generally superior corrosion resistance where Al alloys are concerned. Sensitization becomes an issue in these high magnesium content (> 3 wt%) alloys as Al3Mg2 (β phase), which is anodic to the α-Al matrix, precipitates on grain boundaries after prolonged thermal exposure leading to decreased resistance to intergranular corrosion (IGC), intergranular stress corrosion cracking (IGSCC), and corrosion fatigue (CF). In research, sensitization is typically achieved by accelerating the sensitization process by placing samples in a 100⁰C to 200⁰C oven. In service, naval ships experience sensitization from elevated temperatures ranging from 40⁰C to 50⁰C over a time period of ten or more years, which results in structural performance deterioration. In this work, CF crack growth kinetics (da/dN) as a function of loading frequency (f) for laboratory and in-service sensitized AA5456-H116 microstructures were measured to understand if current lab-based testing reflect CF behavior when material is sensitized in-service. CF growth measurements were obtained on eccentrically-loaded single edge crack tension specimens loaded in the T-L orientation under full immersion in 0.6 M sodium chloride solution. Slow displacement rate testing determined a threshold stress intensity factor, K1SCC, and was used to better inform CF loading parameters. CF testing was conducted at a constant stress intensity range while varying f and applied maximum stress intensity (Kmax). Sensitization exhibited little to no effect on da/dN for both sensitization methods. The da/dN of laboratory sensitized microstructures was just outside the ASTM E647 defined ±50% scatter compared to the in-service sensitized microstructures implying that there is no sensitization method effect. One exception to this observation was the increased da/dN of the in-service intermediate sensitization level over both laboratory (open full item for complete abstract)

Committee: Jenifer (Warner) Locke (Advisor); Eric Schindelholz (Committee Member) Subjects: Materials Science

Doctor of Philosophy, The Ohio State University, 2020, Materials Science and Engineering

Aluminum-magnesium (Al-Mg) alloys offer high strength-to-weight ratios, weldability, and excellent corrosion resistance in marine environments. However, the corrosion resistance of Al-Mg alloys with greater than 3 wt.% Mg degrades after long-term exposure to temperatures as low as 40 °C, a phenomenon called sensitization. Sensitization is caused by precipitation of β-phase (Al3Mg2) on α-Al grain boundaries. Grain boundary β precipitates are anodic to the α-Al matrix and increase susceptibility to intergranular corrosion, stress corrosion cracking (SCC), and corrosion fatigue. Until recently, a majority of corrosion fatigue tests were conducted at a high fatigue loading frequency (f) to estimate the effect of sensitization on corrosion fatigue crack growth rates (da/dN) during service. However, f in marine environments can be on the order of 0.01 Hz or lower. In this work, fracture mechanics-based experiments were utilized to understand the effects that f, sensitization level, and electrochemical potential have on corrosion fatigue da/dN of Al-Mg alloys used in marine environments. In Chapter 2, corrosion fatigue da/dN were quantified for AA5456-H116 as a function of f and sensitization level when loaded under freely corroding conditions in 3.5 wt.% NaCl at a constant stress intensity range (ΔK) and load ratio (R). A critical sensitization level of 24 mg/cm2 was established at and above which da/dN was inversely dependent on f. Sensitization to 70 mg/cm2 accelerated da/dN by approximately 2× at 10 Hz and 5× at 0.03 Hz compared to rates for the as-received microstructure (5 mg/cm2). Below 24 mg/cm2, da/dN were not higher than for the as-received microstructure and were f independent. Three possible explanations for the inverse f dependence were discussed. This research demonstrated the risk of overestimating fatigue life of sensitized AA5456-H116 in marine environments should the f dependence of da/dN not be considered. In Chapter 3, the interplay between SCC an (open full item for complete abstract)

Committee: Jenifer (Warner) Locke Ph.D. (Advisor); Gerald Frankel Ph.D. (Committee Member); Christopher Taylor Ph.D. (Committee Member); Eric Schindelholz Ph.D. (Committee Member) Subjects: Engineering; Materials Science; Metallurgy

Doctor of Philosophy, The Ohio State University, 2019, Dance Studies

This dissertation centers sensuous movement-based performance and practice as particularly powerful modes of activism toward sustainability and multi-species justice in the early decades of the 21st century. Proposing a model of “sensuous ecological activism,” the author elucidates the sensual components of feminist philosopher and biologist Donna Haraway's (2016) concept of the Chthulucene, articulating how sensuous movement performance and practice interpellate Chthonic subjectivities. The dissertation explores the possibilities and limits of performances of vulnerability, experiences of interconnection, practices of sensitization, and embodied practices of radical inclusion as forms of activism in the context of contemporary neoliberal capitalism and competitive individualism. Two theatrical dance works and two communities of practice from India and the US are considered in relationship to neoliberal shifts in global economic policy that began in the late 1970s. The author analyzes the dance work The Dammed (2013) by the Darpana Academy for Performing Arts in Ahmedabad, India, in relationship to the Narmada Bachao Andolan—or, the Movement to Save the Narmada River—on which it was based, as well as to India's history of modern dance, nationalism, and women's movements. She discusses How to Lose a Mountain (2012) by the Dance Exchange in Washington, DC, alongside the anti-mountaintop removal movement in Appalachia to which the work speaks, and in relationship to the Dance Exchange's “Moving Field Guides,” the choreographic and community-based education methods created and utilized in the piece's creation, as modes of sensuous ecological activist performance and pedagogy. The primary somatic practices of the transnational contact improvisation community and the interconnected transnational Burning Man community, contact improvisation (CI) and ecstatic dance, are studied as practices of pilgrimage and nomadic subjectivization, which the author argues foster Chthoni (open full item for complete abstract)

Committee: Harmony Bench PhD (Committee Chair); Hannah Kosstrin PhD (Committee Member); Mytheli Sreenivas PhD (Committee Member); Ann Cooper Albright PhD (Committee Member) Subjects: Dance; Gender Studies; Performing Arts

MS, University of Cincinnati, 2017, Medicine: Immunology

Food allergy is defined as an abnormal immune response following ingestion of food-based allergens. Ingestion of a food allergen, by a sensitized individual, can induce shock and cause the development of different localized responses such as urticaria, wheezing, cramping, vomiting, or diarrhea. Food allergy is a type I hypersensitivity that is mast cell- and basophil-dependent; an absorbed allergen binds to IgE associated with the high-affinity IgE receptor, Fc?RI, on the cell surface of mast cells and basophils leading to the secretion of compounds causing signs and symptoms. However, the role of mast cells, along with the mediators released, is not well understood. Two mouse models were utilized to investigate the clinical response of food allergy as determined by measuring hypothermia and the development of diarrhea. One model, the active model, is sensitization through injection of a food antigen with an adjuvant. Sensitized mice were then orally challenged two times a week until both hypothermia and diarrhea were observed. The second model, the passive model, requires an intravenous injection of antigen-specific IgE monoclonal antibody (mAb) twenty-four hours prior to an oral challenge with the specific antigen. Previous studies in our lab indicated that an allergic response, modeled in mice utilizing the active immunization method, induces both hypothermia and diarrhea in response to an oral antigen challenge. However, the passive immunization model induces hypothermia without diarrhea. This led to the hypothesis that changes within the gastrointestinal tract induced by active sensitization were required for the development of diarrhea. Our results indicated that mice sensitized to egg white protein (EW), using the active model of sensitization, developed diarrhea in response to a challenge with TNP-BSA after sensitization with IgE anti-TNP mAb. This contrasted with mice that were not actively immunized and only developed a temperature drop to a similar IgE an (open full item for complete abstract)

Committee: Jonathan Katz Ph.D. (Committee Chair); Patricia Fulkerson Ph.D. (Committee Member); Simon Hogan Ph.D. (Committee Member) Subjects: Immunology

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2017, Biological Sciences

The functional and evolutionary conservation of neural circuits of reward is an essential component of survival. Drugs of abuse are known to “hijack” natural reward systems to produce their euphoric and reinforcing effects. Recently, synthetic cathinones have gained popularity among the drug users due to low cost, potency and widespread availability resulting from unclear legal regulatory status. Sharing a chemical structure with amphetamines, synthetic cathinones are likely to pose a significant public health threat. Even though synthetic cathinones have been in use for over a decade, the neuropharmacology, behavioral and physiological effects still remain obscure. This gap in knowledge needs to be urgently addressed in order to understand the basic pharmacological effects, development of treatment/therapy against synthetic cathinone addiction and to define a consistent legal framework to assure regulatory control. Due to the ease of experimental manipulations, modularly organized nervous system, absence of blood-brain barrier and well-characterized behavioral paradigms for drug addiction-like behaviors, crayfish continues to be an ideal model to study the addictive potential of any drug. With highly stereotyped behaviors, and a modularly organized nervous system, crustaceans offer productive research models to study proximate mechanisms of a wide range of behavioral phenomena. The current project has harnessed the advantages of this model system to investigate the behavioral effects of synthetic cathinone in comparison to known stimulants: 4-methylmethamphetamine (4-MMA) vs. mephedrone and 3,4-methylenedioxymethamphetamine (MDMA) vs. methylone. We explored the unconditioned behavioral effects, locomotor activity, sensitization of locomotor response, reward potential and termination effects of the above mentioned drugs at doses of 1, 3, and 10 µg/g. Our results show that all the drugs generate significant locomotor effects in crayfish. When crayfish were exposed t (open full item for complete abstract)

Committee: Robert Huber (Advisor); Moira Van Staaden (Committee Member); Jon Sprague (Committee Member); Andrea Kalinoski (Committee Member); Verner Bingman (Committee Member); Arthur Samel (Other) Subjects: Behavioral Psychology; Behavioral Sciences; Biology; Neurobiology; Pharmacology

MS, University of Cincinnati, 2017, Engineering and Applied Science: Materials Science

Type 316 stainless steel (SS316) is widely used in steam generating plants and water reactor systems due to its superior mechanical properties and corrosion resistance. However, it is still subject to the intergranular corrosion (IGC) and stress corrosion cracking (SCC) in certain environments. To improve the resistance to IGC, grain boundary engineering (GBE) was employed to optimize the grain boundary character distribution (GBCD) of SS316. Multi-cycle of ultrasonic nano-crystal surface modification (UNSM) and subsequent annealing at high temperature was employed in this study to modify the GBCD in the near surface region. The strain induced by UNSM and subsequent annealing modified the GBCD in near surface region until 300um in depth by increasing the population of low Σ coincident site lattice (CSL) grain boundary and by breaking the connection of high angle grain boundaries (HAB). Through surface GBE (SGBE) by UNSM and subsequent annealing, the fraction of low Σ CSLs was increased from 34% in the baseline condition to 54%. Cold rolling and subsequent annealing were also used to modify the microstructure of entire sample by increasing the fraction of low Σ CSLs from 41.1% at baseline to 71.5%. The effect of optimization of GBCD on sensitization and IGC was evaluated by double loop electrochemical potentiokinetic reactivation (DLEPR) testing. Electron Back Scattered Diffraction (EBSD) scanning of the sample after DLEPR test showed that the precipitation of carbides arrested at triple junction types J1 and J2 during sensitization treatment. The degree of sensitization (DOS) in the GBEed condition was lower than that in the solution annealed (SA) condition. Iterative cycles of UNSM and single cycle of cold rolling followed by strain annealing can be very effective in improving the resistance to IGC of SS316.

Committee: Vijay Vasudevan Ph.D. (Committee Chair); Ashley Paz y Puente Ph.D. (Committee Member); Matthew Steiner Ph.D. (Committee Member) Subjects: Materials Science

Master of Science, The Ohio State University, 2017, Materials Science and Engineering

AA5xxx series Al-Mg alloys with greater than ~3.5% Mg experience an acceleration in fatigue crack growth rate (da/dN) as the level of sensitization increases and fatigue loading frequency (f) decreases when loaded in 3.5 wt% NaCl. AA5xxx series alloys, commonly used in naval applications, are known to exhibit decreased resistance to intergranular corrosion (IGC) and intergranular stress corrosion cracking (IGSCC) due to the formation of the active Al3Mg2-ß phase on grain boundaries. ß phase is metallurgically undesirable and forms on grain boundaries when slightly elevated in-service temperatures are experienced for prolonged periods of time, a phenomenon known as sensitization. Previous studies on AA5083-H131 corrosion fatigue (CF) show that da/dN is accelerated by an order of magnitude in the Paris regime for degrees of sensitization greater than or equal to 30 mg/cm2 at a f of 10 Hz and an R of 0.85, however, practical in-service naval ship fatigue loading occurs at 0.15 Hz and below. The results of this work show that, for sensitization levels examined above 33 mg/cm2, previous high-f results cannot be applied to low-f loading. High resolution fracture mechanics based experiments conducted at constant ¿K and R-ratio under full immersion in 3.5% NaCl show that da/dN for heavily sensitized material is highly f-dependent and increases with decreasing f by as much as three orders of magnitude over the as-received unsensitized condition. The result of this work suggests that high-f (10 Hz) testing severely underestimates da/dN for service-type loading of heavily sensitized material. Specifically, for sensitization levels of 37 mg/cm2 and above, da/dN increases with decreasing f by 2 to 3 orders of magnitude for 0.01 Hz loading over 1 Hz loading. Results from this study can enable advancement of service ship structural life prediction by generating data necessary to inform on safe versus unsafe sensitization levels.

Committee: Jenifer Locke PhD (Advisor); Gerald Frankel PhD (Committee Member) Subjects: Engineering; Materials Science

Master of Science (MS), Wright State University, 2016, Physiology and Neuroscience

Separation and Its Effect on the Forced Swim Test In the Guinea Pig Early-life stress such as parental neglect, absence, or abandonment, has been hypothesized to increase the susceptibility for developing depression later in life via sensitization of stress-responsive physiological systems (e.g., pro-inflammatory cytokines, hypothalamic-pituitary-adrenal axis). Guinea pigs offer a potential model, but study has been limited to behavioral observations obtained during maternal separation tests. This thesis examined the generalization of this response by asking whether it would cross-sensitize to behavior in another depressive-related paradigm, the forced swim test. In three experiments, pups underwent three forced swim trials, in shallower or deeper water, 24 h or 9 days after 3-h separation period(s). Immobility duration and latency served as the primary dependent measures. I observed cross sensitization of depressive-like behavior (longer duration of immobility) when pups were tested in the deeper water forced swim test 24 h following maternal separation. Results further confirm use of the guinea pig separation model and suggest sensitization of an underlying depressive-like state rather than particular depressive-like behaviors.

Committee: Michael Hennessy Ph.D (Advisor); Patricia Schiml Ph.D (Committee Member); Michal Kraszpulski Ph.D (Committee Member) Subjects: Developmental Psychology; Neurosciences; Psychobiology

Doctor of Philosophy, Case Western Reserve University, 2015, Materials Science and Engineering

Al-Mg 5xxx alloys are desirable in a wide array of structural applications that require a weldable alloy with good corrosion resistance. However, significant changes in the mechanical properties have been shown to occur after both short-term high temperature (e.g. 175°C, < 100 hours) and long-term low temperature (e.g. 60°C, 1000's hrs) laboratory thermal exposures. Commercially available 5083-H116, 5456-H116 and 5083-H131 alloy plates were thermally exposed to various low and intermediate temperatures for times in excess of 20,000 hrs. Significant changes to the strength and fatigue crack growth behavior have been observed after such exposures. In particular, the longitudinal splitting in the short-transverse (ST) direction has been exhibited during fatigue crack growth of L-T samples tested in laboratory air after sufficient time and temperature exposure combinations. In order to directly examine environmental effects on cracking in the ST plane, slow strain rate tensile tests have been conducted in the S-T orientation in various environments (e.g. Lab Air, Dry, and Corrosive). These tests showed significant reductions in ductility and time to failure depending upon the degree of sensitization and type of environment. In order to quantify these effects in more details, environmentally enhanced cracking experiments using J-based fracture mechanics tests were conducted in similar environments on fatigue-precracked samples in the S-T orientation. The evolution of properties (i.e. fracture/fatigue) and the effects of microstructural features (e.g. grain boundary segregation, grain boundary precipitation, grain orientation and misorientation, etc.) and environmentally enhanced cracking are provided along with the effects of various remediation treatments.

Committee: John Lewandowski (Advisor); Henry Holroyd (Committee Member); Rimnac Clare (Committee Member); Schwam David (Committee Member) Subjects: Engineering; Materials Science; Metallurgy

Doctor of Philosophy, The Ohio State University, 2015, Materials Science and Engineering

5XXX series Al-Mg alloys have been used for marine applications due to their low density, good formability, weldability, and, most notably, resistance to corrosion. However, they can be susceptible to intergranular corrosion (IGC) attack and intergranular stress corrosion cracking (IGSCC). This is due to a highly anodic ß phase (Mg2Al3) relative to the matrix that forms along the grain boundary and decreases corrosion resistance of 5XXX aluminum alloys. The purpose of this study is to develop the proper method to test corrosion inhibition on Al-Mg alloys and investigate the efficiency of inhibitors on sensitized alloys to prevent IGC and IGSCC. During the study of the electrochemical behavior of sensitized AA5083, another issue arose. It became clear that an altered surface layer (ASL) with a recrystallized microstructure having no ß phase at the grain boundaries forms on sensitized AA5083 during polishing, which prevents the exposure of subsurface ß phase on an as-polished surface. Selective dissolution of ß phase occurred when it was exposed on the surface as the result of either etching in alkaline solution or cathodic polarization, which caused an increase in the local pH near intermetallic particles. The different corrosion behavior of solutionized and sensitized AA5083 was examined by testing etched samples. Therefore, removal of the ASL is necessary to understand the influence of inhibitors on sensitized AA5083. The effectiveness of corrosion inhibitors was studied on sensitized and solutionized AA5083 with and without the ASL in 3.5 wt% NaCl solution containing potassium chromate (K2CrO4), sodium silicate (Na2SiO3), or sodium vanadate (NaVO3). Examination of the materials by polarization experiments demonstrated that the ASL was active on solutionized samples and protective on sensitized samples. All inhibitors exhibited a suppression of the cathodic reaction, with chromate also exhibiting anodic inhibition on sensitized material without the ASL as the re (open full item for complete abstract)

Committee: Gerald Frankel Ph.D (Advisor); Rudolph Buchheit Ph.D (Committee Member); Christopher Taylor Ph.D (Committee Member); Narasi Sridhar Ph.D (Other) Subjects: Engineering; Materials Science

Doctor of Philosophy, The Ohio State University, 2014, Biophysics

Radiosensitization of biological material such as cancer cells by heavy elements (high atomic number Z or HZ) has been studied as a possible means to improve radiation therapy and imaging for the diagnosis and treatment of cancer. In particular, the energy deposition by low vs. high energy X-rays (LEX & HEX, respectively) has been compared. Computations and simulations have shown that LEX interact favorably with HZ sensitizers by depositing more energy. In contrast, HEX interact predominantly by photon scattering regardless of Z of both the target and sensitizer. Monte Carlo simulations have shown that in comparison to unsensitized tissue models, irradiation of HZ sensitized models resulted in up to a factor of 2 enhancement in dose deposition when performed with LEX, while in contrast dose enhancement with HEX resulted in ~1.2 increase. To verify the computational studies, in vitro experiments were performed with two Pt-based sensitizers, carboplatin and a newly developed terpyridine platinum compound, Typ-Pt, and two different cancer models, the F98 rat glioma and B16 mouse melanoma as models for brain and skin cancer respectively. In agreement with the simulations, the in vitro experimental studies demonstrated decreased survival of HZ-sensitized cells irradiated with LEX compared to HEX. In addition, fundamental physics involving resonant absorption and fluorescence of monochromatic X-rays also was explored, with potential radiotherapeutic applications. Due to the very high probabilities for interaction at resonant X-ray energies, the amount of radiation damage at the site of the tumors could be significantly higher even in comparison to LEX. Promising but preliminary experiments were performed both on detecting resonant fluorescence at synchrotron X-ray intensities, and on the development of a broadband-to-monochromatic X-ray converter. The converter consists of using low energy broadband X-rays to preferentially ionize the K-shell electrons of a targe (open full item for complete abstract)

Committee: Anil Pradhan Ph.D. (Advisor); Rolf Barth M.D. (Committee Member); Nilendu Gupta Ph.D. (Committee Member); Michael Tweedle Ph.D. (Committee Member) Subjects: Biophysics; Radiation

Master of Science in Chemistry, Youngstown State University, 2012, Department of Chemistry

Enhanced surface area thin film titania electrodes were prepared by spin coating of a titania sol onto fluorine tin oxide substrates. The electrodes were characterized by profilometry, scanning electron microscopy, and ultraviolet-visible light spectrometry. Capacitance measurements were used to assess surface area enhancement. The propylphosphonic acid derivative of perylene diimide was synthesized for use in sensitization of the titania films. Complete purification of the crude product was complicated due to the low solubility of the dye derivative. Nonetheless, mass spectrometry, gel electrophoresis, nuclear magnetic resonance, infrared spectrometry, and elemental analysis were carried out to characterize the product. Electrochemical measurements were used to study the efficacy of the dye as a titania sensitizer. The results indicate the perylene derivative is energetically capable of water oxidation. However, charge transfer from the dye into the titania layer was not seen. It is believed this is due to an energy band mismatch between the reduction potential of the dye and the conduction band of the titania layer.

Committee: Clovis Linkous Ph.D. (Advisor); Sherri Lovelace-Cameron Ph.D. (Committee Member); Howard Mettee Ph.D. (Committee Member) Subjects: Chemistry

Master of Science (MS), Wright State University, 2010, Anatomy

Maternal separation in guinea pigs produces a biphasic response consisting of an active behavior phase followed by a phase of passive behavior (crouched stance, piloerection, and eye closure). Previous studies suggest that pro-inflammatory cytokines mediate passive behavior during the passive phase. It is also known that guinea pig pups separated on two consecutive days show a significant increase (sensitization) in full passive behavior on the second day. The current study examined the persistence and role of pro-inflammatory activity in the sensitization of passive behavior in maternally separated guinea pigs. Guinea pig pups were assigned to one of four groups differing in their treatment on Day 1. The groups were either: (1) injected with saline and not separated; (2) injected with saline and separated; (3) injected with lipopolysaccharide (LPS) to induce cytokine activation and not separated; or, (4) injected with LPS and separated. All pups were separated on Day 2 and again on Day 5. By Day 5, sensitization of passive behavior was observed for all groups. LPS on Day 1 did not increase passive behavior on Day 2, but appeared to enhance the effect of separation on Day 5. These data indicate that sensitization of the passive behavior of maternally separated pups persists beyond a single day. Further the results show that LPS induced activation of pro-inflammatory activity is not sufficient to account for the initial sensitization, but does appear to enhance later sensitization effects.

Committee: Michael Hennessy PhD (Advisor); Patricia Schiml-Webb PhD (Committee Member); John Pearson PhD (Committee Member) Subjects: Psychobiology

Master of Science (MS), Wright State University, 2009, Anatomy

The current study examined the behavioral sensitization of guinea pig pups in response to consecutive days of maternal separation. In the first experiment, guinea pigs that received centrally administered artificial cerebrospinal fluid or IL-10 exhibited sensitization of passive behaviors from Day 1 to Day 2. IL-10 decreased the levels of passive behaviors on Day 1, as well as the increase on Day 2. The second experiment used unoperated pups, which also showed sensitization of the passive response from Day 1 to Day 2, though the effect appeared reduced relative to control pups of Experiment 1. Collectively, this investigation confirms previous evidence that passive behaviors are due in part to pro-inflammatory cytokines. It also provides evidence that the increase in passive measures from the first separation to the second may be caused by a sensitization of pro-inflammatory mechanisms.

Committee: Michael Hennessy (Advisor); Patricia Schiml-Webb (Committee Member); John Pearson (Committee Member) Subjects: Psychology

MS, University of Cincinnati, 2007, Medicine : Environmental Health

Objectives: Characterize the natural history of allergic sensitization and compare three definitions of skin prick test (SPT) positivity in infants born to an atopic parent. Study Design: Secondary data analysis of a prospective, high-risk birth cohort. Results: In a cohort of 477 infants, food allergen sensitization decreased from 11.7% at 12 months to 8.6% at 24 months while aeroallergen sensitization increased from 15.9% to 34.0%. Individual food allergen and aeroallergen persistence rates ranged from 0-55.6% but overall aeroallergen sensitization persisted at 61.8%. There was no statistical difference between the three SPT positivity definitions. Conclusions: Food allergen and aeroallergen sensitization begin in infancy. Although individual allergen sensitization was largely transient, overall aeroallergen sensitization persisted at 24 months. High-risk infants should be screened using the standard definition of a positive SPT to identify those at increased risk for the development of allergic disease.

Committee: Dr. James Lockey (Advisor) Subjects: