Master of Arts, The Ohio State University, 2021, Art Education

This research aims to explore the potential of reflective teaching in higher education during a time of great uncertainty. This research also examines the possibilities of critical dialogue in a spatially disconnected classroom. Even though the pandemic of 2020-2021 has thrown the entire world into an extended period of crises, education has not stopped. When classrooms become sites of hidden vulnerabilities, undecidedness and disconnection, how can a teacher continue to focus on facilitating critical pedagogy and meaningful education? Through an investigation that utilizes teacher reflective participatory action research questions and solutions that bridge theories of critical dialogue with a higher education classroom in the pandemic is shared.

Committee: Christine Ballengee Morris (Advisor); Jennifer T. Eisenhauer Richardson (Committee Member) Subjects: Art Education; Education; Teaching

Master of Science (M.S.), University of Dayton, 2018, Electro-Optics

The ultrafast fiber laser system, which can generate the pulse with short duration and high peak power, has many technological applications. The mode-locking mechanism is widely applied to construct an ultrafast laser system. The saturable absorber action, which is characterized by higher transmittance at higher power input, is the key component to make a passive mode-locked laser. The thesis is focused on the simulation of the nonlinear optical loop mirror (NOLM) and the nonlinear amplifying loop mirror (NALM) inside the fiber laser cavity to create a fast saturable absorber action. Relationships between NOLM/NALM properties and output pulses' peak power and energy are discussed in detail. In particular, the transform-limited pulse characteristics of both pulse duration and spectral width are examined. The generation of shorter pulses with higher peak power are explored.

Committee: Andy Chong (Advisor); Imad Agha (Committee Member); Chenglong Zhao (Committee Member); Joseph Haus (Committee Member) Subjects: Optics

Doctor of Philosophy, The Ohio State University, 2012, Pharmacy

Human African trypanosomiasis (HAT) and leishmaniasis are identified by the World Health Organization (WHO) as neglected tropical diseases (NTDs), together with Chagas disease and Buruli ulcer. These NTDs mostly affect people in remote or rural area, and there are very limited control and therapeutic options. The investment on research and development against NTDs is insufficient. Human African trypanosomiasis (HAT) is a vector-borne parasitic disease caused by Trypanosoma brucei subspecies. Transmitted by the tsetse fly, the disease mainly affects rural populations in sub-Saharan Africa and is fatal if untreated. New drugs are needed against HAT that are safe, affordable, easy to administer, active against first and second stage disease, and effective against both subspecies of T. brucei. From medicinal chemistry investigation in Karl Werbovetz group, several N1-substituted 1,2-dihydroquinoline-6-ols were discovered displaying nanomolar IC50 values in vitro against T. b. rhodesiense and selectivity indexes (SI) up to >18,000. OSU-40 (1-benzyl-1,2-dihydro-2,2,4–trimethylquinolin-6-yl acetate) is selectively potent against T. b. rhodesiense in vitro (IC50 = 14 nM, selectivity index = 1700), and has been proposed to cause the formation of reactive oxygen species (ROS) in African trypanosomes. In the present study, we sought to provide further support for the hypothesis that OSU-40 kills trypanosomes through oxidative stress. Inducible RNAi interference (RNAi) was applied to down-regulate key enzymes in parasite antioxidant defense, including trypanothione synthetase (TbTryS) and a superoxide dismutase (TbSODB). Both TbTryS RNAi-induced and TbSODB RNAi-induced cells showed impaired growth and increased sensitivity towards OSU-40 by 2.4-fold and 3.4-fold respectively. Decreased expression of key parasite antioxidant enzymes was thus associated with an increased sensitivity to OSU-40, consistent with the hypothesis that OSU-40 acts through oxidative stress. Finally, th (open full item for complete abstract)

Committee: Karl Werbovetz PhD (Advisor); Mark Drew PhD (Committee Member); Werner Tjarks PhD (Committee Member); Juan Alfonzo PhD (Committee Member) Subjects: Parasitology; Pharmacy Sciences

Doctor of Philosophy, The Ohio State University, 2006, Plant Pathology

Efficacy and physical mode of action (pre- and post-infection activity) of azoxystrobin, pyraclostrobin, mefenoxam, and phosphorous acid for control of strawberry leather rot (LR), caused by Phytophthora cactorum, was evaluated on a commercial farm and under greenhouse conditions. In addition, the distribution of the sensitivity of P. cactorum isolates to azoxystrobin was determined in vitro. In field trials all fungicide treatments had significantly less LR than the untreated control and there were no significant differences in LR incidence among any fungicide treatments during both years of testing. To evaluate the physical mode of action of the previously mentioned fungicides strawberry plants (‘Honeoye') and attached fruits were sprayed with fungicides at 2, 4 and 7 days before inoculation with a zoospore suspension or 13, 24, 36, or 48 hours after inoculation. Azoxystrobin and pyraclostrobin provided protectant activity for up to 7 days, but only slight curative activity when applied 13 hours after inoculation. Phosphorous acid and mefenoxam also provided protection for up to 7 days and curative activity of at least 36 hours. No significant differences in protectant activity between tested fungicides were observed. Sensitivity distributions of P. cactorum isolates, causing crown rot (CR) and LR, to azoxystrobin were determined based on mycelial growth and zoospore germination. Radial growth of mycelia on lima bean agar amended with 0.001, 0.01, 0.1, 1.0, 10 and 30 ig/mL of azoxystrobin plus 100 ig/mL of salicylhydroxamic acid (SHAM) was measured after 6 days. Effects on zoospore germination were evaluated in aqueous solutions of 0.005, 0.01, 0.05, 0.1, 0.5, and 1.0 ig/mL of azoxystrobin after 4 h of incubation in 96-well microtiter plates. Effective dose (ED50) for mycelial growth ranged from 0.16 to 12.52 ig/mL for LR isolates, and 0.1 to 15 ig/mL for CR isolates. The Kolmogorov-Smirnov test showed significant differences (P<0.001) between the two distribution (open full item for complete abstract)

Committee: Michael Ellis (Advisor) Subjects: Agriculture, Plant Pathology

Doctor of Philosophy, The Ohio State University, 2006, Computer and Information Science

In Computer Vision applications, there often exist the need to extract features to facilitate the process of analysis and recognition. In our key feature approach, we first study a computational framework of modeling human action styles, which extracts key motion trajectories for analysis and recognition assuming a given representation (e.g., trajectories and three-mode PCA). By emphasizing those key trajectories, the framework is capable of improving the modeling efficiency and accuracy, while being adaptive to multiple action style modeling criteria. We then extend the key feature approach in considering a general problem of recognition and analysis without an explicit representation (e.g., using raw images). We want to automatically extract key features to form an optimal internal representation of the data (images), which is a fundamental problem in Computer Vision research. By emphasizing the key information for representation, our approach is capable of improving the efficiency and accuracy for analysis and recognition in a wide range of applications in Computer Vision.

Committee: James Davis (Advisor) Subjects: Computer Science