773 matches in the database.
These are records: 1 - 30.
[1] [2] [3] [4] [5] … [26]
1.
Yablinsky, Clarissa A.
Characterization of Fatigue Mechanisms in Ni-based Superalloys.
Degree: PhD, Materials Science and Engineering, 2010, Ohio State University
► Ni-based superalloys are important for turbine engine airfoil applications. Historically, creep has…
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▼ Ni-based superalloys are important for turbine engine airfoil applications. Historically, creep has been the main failure mode and thus creep mechanisms have been the subject of numerous studies. However, modern airfoil designs maintain cooler temperatures, and consequently creep is no longer the primary failure mode. Rather, in the cooled components, experience and experimental studies have shown that fatigue is the life-limiting factor. The changing cause of failure highlighted the need for a comprehensive study of fatigue deformation mechanisms. Information about crack propagation and the associated deformation mechanisms has allowed appropriate design changes based on fatigue as a life-limiting factor. The focus of the study will be on a monocrystalline Ni-based superalloy, René N5, which is currently used for airfoils. Compact tension specimens were tested under cyclic loading conditions to determine the influence of microstructure and material properties on crack propagation and fatigue failure. The crack growth rate as a function of temperature, environment, frequency, and crystallographic orientation was determined. High resolution scanning electron microscopy was used to examine the fracture surface on length scales from nano to macro. Deformation mechanisms in the plastic zone ahead of the crack tip and within the plastic wake of the crack were studied using TEM and FIB techniques. Environment and frequency seem to have a larger effect on fatigue crack growth rates and threshold stress intensity factor ranges, while temperature and orientation effects are present, but not as dramatic. In the normal blade orientation, (001)[100], mode I crack propagation was prevalent, with mode II crack propagation found at higher ΔK values. Interdendritic particles appear to be slowing crack growth rates in the threshold region of specimens tested in air. Microstructural analysis showed no change in γ’ precipitate size or morphology with temperature or stress. From TEM investigations, it is theorized that a combination of mechanisms is occurring during testing, which is the reason there is no universal trend with temperature for the threshold stress intensity factor ranges. The mechanisms discussed include Kear-Wilsdorf locking, oxide-induced crack closure, and crack tip softening due to γ’ depletion.
Advisors/Committee Members: Flores, Katharine.
Subjects: Aerospace materials; Engineering; Materials science; Metallurgy
Keywords: Ni-based Superalloys; Fatigue Crack Growth; Rene N5; Fatigue; Temperature; Environment; Frequency; Orientation; Characterization; TEM
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2.
Yablonsky, Eugene.
Characterization of operators in non-gaussian infinite dimensional analysis.
Degree: PhD, Mathematics, 2003, Ohio State University
► It is known that many constructions arising in the classical Gaussian infinite…
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▼ It is known that many constructions arising in the classical Gaussian infinite dimensional analysis can be extended to the case of more general measures. One of such extensions can be obtained through biorthogonal systems of polynomials and generalized functions. That approach was discussed by Yu. Daletsky, S. Albeverio, Yu. Kondratiev, L.Streit, W. Westerkamp, J.-A. Yan, J. Silva, et al., who considered a broad class of non-degenerate measures with analytic characteristic functionals. In this thesis we develop a theory of white noise operators, i.e., linear continuous operators from a nuclear Fréchet space of test functionals to its dual space in this more general setting. We construct an isometric integral transform of those operators into the space of germs of holomorphic functions on a locally convex infinite dimensional nuclear space. Using such transform we provide characterization theorems and consider the biorthogonal chaos expansion for white noise operators. We also provide a biorthogonal construction for integral kernel operators, and show that any white noise operator can be represented by a strongly convergent series of those integral kernel operators. In addition, we discuss various examples of spaces of test functions in infinite dimensional analysis and relations among them.
Advisors/Committee Members: Dynin, Alexander.
Subjects: Mathematics
Keywords: White Noise Operators; Biorthogonal Appell systems
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4.
Yacks, Craig Thomas.
A Disaster Preparedness Plan for Small Islands: The Case of Santorini, Greece.
Degree: MCP, Design, Architecture, Art and Planning : Community Planning, 2006, University of Cincinnati
► Due to their locations around the world, small islands are especially vulnerable…
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▼ Due to their locations around the world, small islands are especially vulnerable to natural disasters. Most of the islands are in hurricane and cyclone paths, and many are of volcanic origin, thus increasing the threat of an earthquake. However, the natural beauty of these locals and the uniqueness of their geographical features often make these islands magnets for tourism. As a result, the limited area for development is often dense, located near the most aesthetically striking features which also are the most vulnerable locations. The goal of the study was to prove that the present models for small island disaster planning are inadequate, and furthermore, a more complete model could be developed. By not just comparing the two models and case studies, but by understanding the methodologies of each, as well as citing additional cases, these goals were achieved.
Advisors/Committee Members: Romanos, Michael.
Keywords: Disaster Planning; Small Island; Disaster preparedness; Disaster; Santorini
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5.
Yadama, Gautam Nagabushana.
Comparative analysis of governmental and nongovernmental community development programs: A study of community forestry programs in Andhra Pradesh, India.
Degree: PhD, Sociology, 1990, Case Western Reserve University
► This study compares the effectiveness of Nongovernmental and Governmental organizations involved in…
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▼ This study compares the effectiveness of Nongovernmental and Governmental organizations involved in planning and implementing community forestry and social forestry programs. The study was conducted in Vishakapatnam district, Andhra Pradesh, India. The following study also compares the participation of small and large farmers in these community development programs to determine if non-governmental organizations are in fact more receptive to low income groups than governmental organizations. Data were collected in two non-governmental and two governmental social fores try programs. The study is based on a sample size of two hundred respondents. One hundred respondents were from the non-governmental organizations and the remaining one hundred respondents were from the governmental organizations. The study found that participants in governmental social forestry programs were more involved in decision making and implementation aspects of these programs than the participants in non-governmental organizations. The study also found that the larger farmers were more involved in decision making activities and the small farmers were more involved in implementation activities of these programs. Overall the study also concludes that non-governmental organizations are not any more effective in involving the poor in project activities than the governmental social forestry programs. The findings of the study challenge the current assumption that non-governmental organizations are more effective than governmental organizations in carrying out development work. The study calls for a closer monitoring and evaluation of non-governmental organizations and a reevaluation of the assumption that invariably non-governmental development work is better than governmental development work.
Advisors/Committee Members: Coulton, Claudia J.
Keywords: community forestry Andhra Pradesh
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6.
Yadav, Ajay D.
Process Analysis and Design in Stamping and Sheet Hydroforming.
Degree: PhD, Industrial and Systems Engineering, 2008, Ohio State University
► This thesis presents initial attempts to simulate the sheet hydroforming process using…
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▼ This thesis presents initial attempts to simulate the sheet hydroforming process using Finite Element (FE) methods. Sheet hydroforming with punch (SHF-P) process offers great potential for low and medium volume production, especially for forming (a) lightweight materials such as Al- and Mg- alloys and (b) thin gage high strength steels (HSS). Sheet hydroforming has found limited applications and is thus still a relatively new forming process. Therefore, there is very little experience-based knowledge of process parameters (namely forming pressure, blank holder tonnage) and tool design in sheet hydroforming. For wide application of this technology, a design methodology to implement a robust SHF-P process needs to be developed. There is a need for a fundamental understanding of the influence of process and tool design variables on hydroformed part quality. This thesis addresses issues unique to sheet hydroforming technology, namely, (a) selection of forming (pot) pressure, (b) excessive sheet bulging and tearing at large forming pressures, and (c) methods to avoid leaking of pressurizing medium during forming. Through process simulation and collaborative efforts with an industrial sponsor, the influence of process and tool design variables on part quality in SHF-P of axisymmetric punch shapes (cylindrical and conical punch) is investigated.In stamping and sheet hydroforming, variation in incoming sheet coil properties is a common problem for stamping plants, especially with (a) newer light weight materials for automotive applications (aluminum-, magnesium- alloys) and (b) thin gage high strength steels. Even though incoming sheet coil may meet tensile test specifications, high scrap rate is often observed in production due to inconsistent material behavior. Thus, tensile test specifications may not be adequate to characterize sheet material behavior in production stamping/hydroforming operations. There is a strong need for a discriminating method for testing incoming sheet material formability. The sheet bulge test emulates biaxial deformation conditions commonly seen in production operations. This test is increasingly being applied by the European automotive industry, especially for obtaining reliable sheet material flow stress data that is essential for accurate process simulation. This thesis presents a new 'inverse-analysis' methodology for calculating flow stress curves at room temperature, using the biaxial sheet bulge test. This approach overcomes limitations of previously used closed-form membrane theory equations and exhibits great potential for elevated temperature bulge test application. To verify the developed methodologies presented in this thesis, selected case studies are presented, to (a) demonstrate the successful application of finite element (FE) simulation in tool design, process sequence design and springback reduction in stamping and sheet hydroforming and, (b) validate the developed methodology for automation/standardization of tool and process sequence design procedure and recording of existing design guidelines in transfer die stamping.
Advisors/Committee Members: Altan, Taylan.
Subjects: Automotive materials; Industrial engineering; Mechanical engineering
Keywords: sheet metal forming, sheet hydroforming, process simulation, material characterization
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7.
Yadavalli, Srujana Samhita.
ROLE OF PHENYLALANYL-TRNA SYNTHETASE IN AMINOACYLATION AND TRANSLATION QUALITY CONTROL.
Degree: PhD, Microbiology, 2012, Ohio State University
► Translational quality control occurs at several steps, including amino acid selection by…
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▼ Translational quality control occurs at several steps, including amino acid selection by aminoacyl-tRNA synthetases (aaRSs). Phenylalanyl-tRNA synthetase (PheRS) misactivates Tyr but is able to correct the mistake using a proofreading activity named editing. Using Escherichia coli PheRS as a model, we show that PheRS editing is the major proofreading step that prevents incorporation of Tyr at Phe codons during translation. In addition, mischarged aa-tRNAs released by PheRS can be resampled via a trans editing pathway that reduces the overall error rate of aminoacyl-tRNA synthesis, providing an additional quality control step prior to translation elongation. While many aaRSs, such as PheRS, actively edit noncognate amino acids, editing mechanisms are not evolutionarily conserved and their physiological significance remains unclear. To address the connection between aaRSs and mistranslation, we used the evolutionary divergence of tyrosine editing by PheRS as a model system. Certain PheRSs such as those in Mycoplasma species are naturally error-prone and display a low level of specificity consistent with elevated mistranslation of the proteome. Mycoplasma mobile PheRS (MmPheRS) lacks canonical editing activity, relying instead on alternate low stringency quality control pathways. This mechanism of discrimination is inadequate for organisms where translation is usually more accurate. As a result, MmPheRS failed to support E. coli growth. However, minor changes in the defunct editing domain of the MmPheRS are sufficient to restore amino acid specificity and sustain E. coli growth, indicating that translational accuracy is an evolutionarily adaptable trait. These findings indicate a mechanism by which aaRSs facilitate adaptation to changes in cellular physiology by altering the accuracy of translation of specific codons, which may prove advantageous for growth under different environmental conditions. In addition to its role in cytoplasmic protein synthesis, PheRS is also essential for the proper functioning of organelles such as mitochondria. Structural and functional studies revealed that rearrangement of the RNA-binding and catalytic domains of human mitochondrial PheRS (mtPheRS) between closed and open states are required for completion of the aminoacylation reaction. These results combined with corroborating SAXS experiments indicate that conformational flexibility of the two functional modules in mtPheRS is essential for its phenylalanylation activity, consistent with the modular evolution of the aaRSs. Defects in mitochondrial translation can lead to a number of mitochondrial diseases like diabetes, deafness, encephalopathy and other myopathies. Although mutations in mitochondria-encoded tRNAs are known to be pathogenic, it has recently become apparent that mutations in nuclear-encoded components of the mitochondrial translation machinery, such as the mtPheRS, could also lead to disease. Non-synonymous single nucleotide polymorphisms (ns-SNPs) occurring in regions distal to mtPheRS catalytic site, affect overall aminoacylation indirectly through refolding specific defects. Pathogenic mutations in mtPheRS associated with infant cardiomyopathy impact function directly by impairing substrate binding and amino acid activation. Our work sheds light on the effects of pathogenic mutations in mtPheRS, which can provide a molecular basis for related mitochondrial diseases.
Advisors/Committee Members: Ibba, Michael.
Subjects: Biochemistry; Microbiology
Keywords: protein synthesis; tRNA; aminoacyl-tRNA synthetase; quality control; editing; mitochondrial disease
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8.
Yadavalli, Suhrida.
The impact of executive function on medication adherence in people living with HIV.
Degree: MA, College of Arts and Sciences / Department of Psychology, 2009, Kent State University
► The present study investigated whether cognitive function was associated with adherence to…
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▼ The present study investigated whether cognitive function was associated with adherence to highly active antiretroviral therapy (HAART) in 32 asymptomatic and symptomatic HIV-infected men and women. Participants (53% African American) were recruited from Louis Stokes Cleveland Veterans’ Affairs Medical Center (LSCDVAMC) and were interviewed and tested on site. Cognitive domains assessed were attention, executive function and information processing speed. Other variables included adherence, substance use, depression and medical variables. A multiple hierarchical regression analysis revealed a significant model fit for the association between cognitive variables and adherence at one month. High levels of previously undetected cognitive impairment were found. High levels of adherence were also reported. People with HIV/AIDS may benefit from monitoring of adherence at each visit and utilization of appropriate interventions as needed. Further, this population may benefit from regular screening for cognitive impairment and referral for complete neuropsychological evaluation as appropriate. Further studies need to investigate the relationship between cognitive function and medication adherence in people living with HIV.
Advisors/Committee Members: Gunstad, John.
Subjects: Psychology
Keywords: HIV, executive function, adherence
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9.
Yadav, Priyanka.
Factors affecting mosquito populations in created wetlands.
Degree: MS, Environmental Science, 2009, Ohio State University
► Constructed, created and restored wetlands are gaining popularity due to multiple benefits…
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▼ Constructed, created and restored wetlands are gaining popularity due to multiple benefits they provide. However, there is a concern that wetlands increase mosquito breeding in urban areas. This is especially due to the recent concern regarding mosquito borne viral encephalitis and other diseases. Published studies to quantify mosquito population in constructed and natural wetlands are inconclusive. This study quantified the population of mosquitoes from two experimental flow-through created wetlands and two stormwater fed wetland at the Olentangy River Wetland Research Park (ORWRP) in Columbus, Ohio in summer. Sampled mosquitoes were identified to species level to investigate their disease vector potential. The study also compared mono specific and multispecies small (1 m2) mesocosms being used for another experiment. The flow-through created wetlands were less conducive to mosquito breeding compared to the pond (p<0.00001) and stormwater wetland (p=0.002). Outflow regions and emergent vegetation sites in the flow-through wetlands were most conducive to mosquito breeding than were inflows (p=0.009) and floating vegetation sites (p=0.023). Mixed vegetation communities (Sparganium eurycarpum, Juncus effusus, and Schoenoplectus tabernaemontani) rather than mono specific Typha communities provided most conducive environment for mosquito breeding (p<0.0001). Mesocosm plots with steady inflow (10 cm depth) and with deep water (20 cm) in summer and shallow water (5 cm) in spring had higher mosquito densities than did mesocosm plots with pulsed flow (10 cm depth with inflow rate according to the river stage) and deep water (20 cm) in spring and shallow water (5 cm) in fall. Among water quality parameters, conductivity (p=0.004) and, to a lesser extent, dissolved oxygen (p=0.052) correlated with mosquito larval density (adjusted R2 of 0.67). Six mosquito species identified in all water bodies were Cx. pipiens, Cx. salinarius, Cx. restuans, Ur. sapphirina, An. quadrimaculatus, and An. punctipennis. Among these Cx. pipiens and Cx. salinarius are both avian and mammalian blood feeders and hence are potential bridge vectors of the encephalitis viruses. An. quadrimaculatus, one of the most potent vector of malaria in U.S. and also a major host of the nematode that causes dog heartworm, was present in all the water bodies. Cx. pipiens was the dominant mosquito species in all the water bodies sampled. The information obtained can be incorporated in construction design of wetlands, can be used in the future to target mosquito control tactics and can provide baseline at the ORWRP for future surveillance.
Advisors/Committee Members: Grewal, Parwinder.
Subjects: Environmental science
Keywords: EXPERIMENTAL WETLANDS, CREATED WETLANDS, MOSQUITO LARVAE, ORWRP
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10.
Yadav, Priyanka.
Below ground biological control in urban landscapes and assessment of factors influencing its abundance.
Degree: MS, Entomology, 2012, Ohio State University
► The practice of urban agriculture has recently gained momentum due to its…
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▼ The practice of urban agriculture has recently gained momentum due to its potential of making cities self-reliant and revitalizing disadvantaged neighborhoods enhancing food security, generating new employment opportunities and access to fresh fruits and vegetables. However, the suitability of urban soils for agricultural use is questionable given their highly disturbed and contaminated nature,. My research examined, the inherent biological control activity provided by urban soils and ways to enhance such this activity to support sustainable crop production. We quantified belowground biocontrol activity in urban gardens and vacant lots in three Ohio cities, Columbus, Cleveland, and Akron, using an in-situ insect baiting technique. We hypothesized that belowground biocontrol services would differ between gardens and vacant lots and different biocontrol organisms may be influenced by variation in habitat structure characteristics of these sites. Biocontrol activity, as assessed by % mortality of baited insects, varied between 63% and 82% with higher activity often recorded in vacant lots compared with gardens. Major contributors of potential below-ground biological control activity were ants, followed by microbial pathogens and entomopathogenic nematodes, respectively. Ants showed higher % mortality in vacant lots than in urban gardens (p value = 0.04) whereas microbial pathogens exhibited higher mortality in gardens than vacant lots (p value = 0.002). Such substantial biological control activity is promising and suggests that enhancing this inherent biological control activity can substantially reduce agricultural inputs. As the biocontrol organisms are sensitive to variations in management practices, we further studied these sites for soil health/quality characteristics so as to generate hypotheses regarding practices that will increase activity of these biocontrol organisms. We found that potential biocontrol service by ants (as assessed by mortality of bait insect caused by ants) is associated negatively with enrichment index and NH4-N; and positively with number of omnivore nematodes and soil moisture. In contrast, mortality by microbes is positively associated with enrichment index, NH4-N, and negatively with the number of omnivore nematodes and soil moisture. Mortality by EPNs is associated positively with plant parasitic index, number of cp-1 class bacterial feeding nematodes, and negatively with combined maturity index, cp-2 class bacterial feeding nematodes and NO3-N. Such site assessment for biocontrol agents and determining practices to enhance their activity in urban gardens will likely provide for a safe and sustainable pest control strategy to enhance the quality of food crops and environmental health. We expect that the results from this study can be integrated in establishment and management of urban gardens in Ohio and elsewhere and will contribute to improvements in human and environmental health.
Advisors/Committee Members: GREWAL, PARWINDER S.
Subjects: Entomology
Keywords: Belowground biological control; urban landscapes
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11.
Yadav, Santosh.
The Energetics of Water Interactions with Adult and Neonatal Skin.
Degree: PhD, Engineering : Chemical Engineering, 2009, University of Cincinnati
► The water content of skin has a significant impact on skin properties;…
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▼ The water content of skin has a significant impact on skin properties; sufficient hydration is necessary to keep the skin supple, flexible, and smooth. To understand more completely the water retention properties of the human skin barrier, physical macroscopic properties must be related to the structural organization of the stratum corneum (SC). Water, lipids, and natural moisturizing factor (NMF) influence the molecular structures that affect the properties of SC, including water sorption and binding enthalpy. In this dissertation, a study of water vapor interaction with human adult and neonatal foreskin stratum corneum (SC) and also with hair and nail is presented in detail. This study also focuses on variants of adult human SC, including delipidized and water-washed delipidized SC, to identify the influences of the principal components of SC on water sorption. The procedure consisted of conjoint water vapor sorption and heat flow measurements. The heat of sorption of water in excised human adult cadaveric and surgical SC, neonatal SC, hair and nail at various relative humidities was measured in an isothermal calorimeter at 32°C. Calorimetric measurements, combined with gravimetric water sorption isotherms, were used to calculate the integral and differential enthalpies and entropies associated with binding of water to SC. Structural and conformational changes in delipidized and water washed delipidized SC in the dried and hydrated states were analyzed using Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy. Structural differences were also analyzed in nails, hair, surgical and neonatal SC. ATR-FTIR results were also interpreted in terms of transformation of keratins from α-helix to β-sheet and random coils, determined using the Amide I band. The thermodynamic properties obtained from calorimetric data were interpreted in conjunction with spectroscopic data. The magnitudes of the differential enthalpy, the differential free energy and the differential entropy are greatest for adult cadaveric intact SC and least for water-washed delipidized SC and nails. The principal thermal contribution comes from the interaction of water with keratins. The enthalpy and entropy of water sorption in SC are consistent with a picture in which water first binds tightly to polar sites on keratin, replacing keratin-keratin bonds with energetically favorable keratin-water bonds. This process swells and softens the tissue, leading to rapid decreases in the magnitudes of the differential thermodynamic properties and with increasing water content. Spectroscopic and water sorption results are consistent with the calorimetric results. Spectroscopic results, in conjunction with the calorimetric results indicate that removing the lipid and NMF components alters the conformation of the keratins. Delipidization converts a fraction of keratin α-helixes to turns and random coils, while water sorption converts a fraction of keratin α-helixes to β-sheet, turns, and random coils. Adult surgical SC is the most appropriate laboratory model to study adsorption and related processes. Cadaveric SC appears to be significantly less ideal, possibly due to changes occurring during preservation and storage. Neonatal SC is less ideal due to differences in ceramide content. Lipids play a key role in maintaining the keratins in a conformation that results in optimum hydration.
Advisors/Committee Members: Degouvea-Pinto, Neville.
Subjects: Chemical engineering
Keywords: Skin Spectroscopy; Delipidized Skin; Skin Hydration; Calorimetry; Thermodynamics of Water Sorption on skin; Thermodynamic modeling
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12.
Yadav, Susheel.
Development of Zero Emission Chromium Plating Process.
Degree: MS, Engineering : Chemical Engineering, 2001, University of Cincinnati
► Hard chromium plating is extensively used in the industry to improve the…
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▼ Hard chromium plating is extensively used in the industry to improve the wear characteristics of metal parts. EPA has identified hexavalent chromium, used in chromium plating, as one of the 17 high-priority toxic chemicals. The purpose of this project was to design a new process that will prevent the release of chromic-acid mist into the workplace. Traditionally, temperature control and mixing have been achieved by bubbling air at the bottom of the plating bath using a sparger. These air bubbles burst at the surface of the plating solution and produce aerosols that are responsible for the chromium emissions. The proposed process uses a silicone fluid layer at the top of the plating solution to trap the aerosols. Mixing and heat transfer are achieved by sparging this fluid. Mathematical models have been developed to predict hexavalent chromium emissions, heat transfer, and health risks associated with conventional plating tanks.
Advisors/Committee Members: Govind, Rakesh.
Keywords: Chromium plating, Hexavalent chromium emissions, Aerosols
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13.
Yadav, Vivek.
VALIDATION OF A TIME-SCALING-BASED MODEL FOR REPRESENTATION OF DYNAMICS IN HUMANS AND ITS APPLICATIONS IN REHABILITATION.
Degree: PhD, Mechanical Engineering, 2010, Ohio State University
► The generation of muscle forces to perform various human movement tasks is…
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▼ The generation of muscle forces to perform various human movement tasks is a complex control problem whose mathematical solution requires complex formulations due to redundancy in muscle actuators. This problem becomes increasingly difficult because the same movement can be generated by following different joint coordination strategies. Literature suggests that the human brain resolves these redundancies using an optimization-based approach. Such approaches, in general, require systems with large computation capabilities to generate a feasible solution. The human brain, however, has seemingly developed a method to solve this problem in a simpler manner. This study proposes a simpler time-scaling-based mathematical model of the dynamics of human movement that eliminates the need for the optimization routines. It is proposed that humans separate the muscle forces required to compensate for gravitational effects and to generate motion. In the framework of the proposed model, the muscle forces required to generate motion for one given speed are scaled to generate the same motion at different speeds. This theory of movement control is applicable under the following three assumptions: 1- Humans have the ability to separate muscle forces required for compensation of gravitational effects from total muscle forces. 2- Time scaling is a characteristic of human movement. 3- The scaling-based solution satisfies the conditions of optimality. Various aspects of this theory of movement control are tested by applying force fields with a custom robotic device. The adaptation of the subjects to the force fields is used to validate the theory. Experiments conducted with 54 healthy individuals provide evidence suggesting that humans may be separating muscle forces required to compensate for gravity from the total muscle forces required to perform motion. The experiments also suggest that scaling is a primary characteristic of human movement that is manifested as various kinematic invariants for human movement reported in the literature. Methods are developed with the same device for assessing rehabilitation during the acute phase of recovery from stroke. Various metrics are developed with the device, and their applicability was tested by comparing arm movement patterns of 8 older and 8 younger healthy subjects. Preliminary results with 3 stroke patients show that the methods developed can be used to assess post-stroke recovery. Application of the model proposed for classifying stroke impairments is proposed, and its applicability in classification and rehabilitation of lost motor function remains to be tested in a clinical setting with experiments involving stroke patients.
Advisors/Committee Members: Schmiedeler, James.
Subjects: Mechanical engineering
Keywords: Robotics, Kinematics, Biomechanics, Human motor control
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14.
Yafetto, Levi.
Biomechanics of Rhizomorph Development in Armillaria mellea.
Degree: PhD, Botany, 2008, Miami University
► Fungal rhizomorphs are complex, multicellular, root-like organs formed through the aggregation, interlacing,…
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▼ Fungal rhizomorphs are complex, multicellular, root-like organs formed through the aggregation, interlacing, and adhesion of millions of tip-growing hyphae. There has been very little research on the invasive mechanism utilized by rhizomorphs to penetrate compacted soils and woody substrates. Initial studies with Meruliporia incrassata, a wood-decay fungus that decomposes wooden components of buildings with an annual value of destruction estimated in millions of dollars, was aimed at inducing rhizomorphs in vitro. This attempt was not very successful, as only mycelial cords were produced. The pathogen Armillaria mellea was therefore chosen because it readily forms rhizomorphs in culture and serves as an excellent model for developmental studies. This dissertation presents findings from experiments designed to study (i) comparative features of rhizomorph anatomy in M. incrassata and A. mellea that support its invasive behavior; (ii) the adaptive growth response of rhizomorphs subjected to mechanical stress; (iii) the biochemical basis of turgor generation within rhizomorphs, and (iv) novel measurements of the forces exerted by growing rhizomorphs. Anatomical studies of rhizomorphs of A. mellea cultured in potato dextrose agar (PDA) revealed zones of hyphal tissues namely, an outer layer of peripheral hyphae, radial hyphae, longitudinal hyphae, and a central cavity. A. mellea rhizomorphs were observed to have faster growth than mycelia in PDA. We determined that increasing concentration of agar stimulated the production of more rhizomorphs, with those in media having higher concentration of agar extending faster with tapered tips. Turgor generation within A. mellea rhizomorphs was shown to be partially due to the accumulation of osmolytes. Erythritol and mannitol were identified using Gas Chromatography/Mass Spectrometry (GC/MS) and quantitatively determined to be the most dominant osmolytes that contribute to turgor generation. Osmometric studies revealed that substantial portion of turgor generated was used to exert pressure at the tip of the rhizomorphs during invasive growth. The varying amounts of force that these A. mellea rhizomorph tips exert were measured, using a sensitive strain gauge. Our experiments provide the first clear picture of the mechanical processes that allow rhizomorphs to function as migratory, exploratory and invasive organs in low-moisture and nutrient-poor environments that present substantial obstacles to fungal colonization.
Advisors/Committee Members: Money, Nicholas P.
Subjects: Botany
Keywords: basidiomycota; biomechanics; fungi; hyphae; invasive growth; osmotic pressure; osmolyte; rhizomorph; spectroscopy; turgor pressure
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15.
Yaganti, Sushmita.
Immunolocalization and Changes in Expression Levels of Glyceroporin HC-3 in Several Tissues of Gray Tree Frogs, Hyla chrysoscelis Under Different Physiological Conditions.
Degree: MS, Biological Sciences, 2009, Wright State University
► Previous studies show that aquaporin HC-3 in gray tree frogs, Hyla chrysoscelis,…
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▼ Previous studies show that aquaporin HC-3 in gray tree frogs, Hyla chrysoscelis, a homolog of mammalian AQP3 is an aqua glyceroporin also responsible for freeze tolerance. Our study tried to localize and compare the protein expression levels of aquaporin HC-3 in seven different organs of gray tree frogs under five different physiological conditions using immuno histofluorescence and western blot. HC-3 was immunolocalized in the epidermis and dermis of the skin, basolateral portion of the collecting ducts in the kidney, red blood cells in the liver and other tissues, muscle Schwann cells and the basolateral portion of the large intestine epithelial membrane. HC-3 cannot be immunolocalized in the stomach and the small intestine tissues. The basolateral expression of aquaporin HC-3 in the epidermis of the skin is similar to the expression in the mammalian skin. The intensity of the labeling was different in the various physiological conditions. There was a noticeable increase in the intensity of the HC-3 expression in warm (hydrated, 23° C, control) skin, kidney and liver compared to dehydrated (loss of 20% of standard body mass over one week at 23° C) and the cold ( hydrated 4° C). The intensity of labeling in large intestine had varied pattern with more expression in the warm, slightly less in the cold and absolutely negligible in the other conditions. The up-regulation of the aquaporin HC-3 protein expression in the dehydrated skin and the kidney may be due to its regulated role in the water conservation whereas its up-regulation in the cold liver can be due to synthesis and release of glycerol in this organ.
Advisors/Committee Members: Goldstein, David.
Keywords: Keywords: Aquaporin, aquaglyceroporin, skin, kidney, liver, muscle, stomach, intestine, Hyla chrysoscelis (Gray tree frog).
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18.
Yaghjyan, Lusine.
Determinants of Mammographic Breast Density in Different Subsets of Women.
Degree: PhD, Medicine : Epidemiology (Environmental Health), 2009, University of Cincinnati
► Mammographic breast density is a strong predictor of breast cancer. The current…
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▼ Mammographic breast density is a strong predictor of breast cancer. The current retrospective study determines if the direction and degree of the association between risk factors for breast density and the breast density phenotype differ in the subsets of women stratified by menopausal status, hormone replacement therapy use (HRT), and family history of breast cancer. The study participants were selected from women enrolled in the Fernald Medical Monitoring Program (FMMP). To be included in the study, women were required to have been enrolled in FMMP as adults, be Caucasians, and have had at least one mammogram in FMMP mammography database. Women who had any diagnosis of breast cancer, genetic syndromes and disorders with underdevelopment of breast and small stature, history of mammoplasty, or were transsexual were not eligible for the study. Discordant phenotypes for mammographic breast density (high breast density [cases, N=265] and low breast density [controls, N=860]) were defined using the mammographic breast density assessment from the original radiologists’ readings. The earliest FMMP screening or diagnostic mammogram that had criteria used to define the density phenotype was used as an index mammogram if the woman was 40-80 years old at the time of the index mammogram and had a Body Mass Index (BMI)<35 at the time of the mammogram. The data were analyzed using SAS Statistical Software. Findings of this study suggested a statistically significant effect of parity (protective) and alcohol use (direct) on breast density. A significant effect of age on breast density was limited to 50-<60 year old women. When stratified by menopausal status, BMI showed a significant protective effect and ever use of alcohol showed a significant direct effect on breast density phenotype in premenopausal women, while in postmenopausal women, parity showed a significant protective effect and a family history of breast cancer, age, and HRT use had direct effects on the breast density phenotype. In women who never used HRT, age and BMI showed a significant protective effect. When stratified by any family history of breast cancer, ever use of alcohol (direct effect) and parity (protective effect) were the only predictors of the breast density status and their effect was stronger in women with a family history of breast cancer compared to women without a family history of breast cancer. Findings of the study suggested that BMI, parity, use of hormone replacement therapy, and ever use of alcohol appear to be the most important predictors of the breast density phenotype in different subsets of women stratified based on their menopausal status, history of HRT use, and a family history of breast cancer. The results also suggested that different strength of the effect of parity and alcohol on breast density in women with and without a family history of breast cancer could be the result of gene-environment interactions. A subset analysis on 180 women for the effects of several single nucleotide polymorphisms (SNPs) in the estrogen metabolism pathway genes on the breast density phenotype is underway.
Advisors/Committee Members: Pinney, Susan.
Subjects: Epidemiology
Keywords: mammographic breast density; determinants; extreme breast density phenotypes; breast density assessment
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19.
Yagi, Rieko.
Bcl-2 Regulates Chondrocyte Phenotype Through MEK-ERK1/2 Pathway; Relevance to Osteoarthritis and Cartilage Biology.
Degree: PhD, School of Biomedical Sciences, 2005, Kent State University
► Bcl-2 is an anti-apoptotic protein that has recently been shown to regulate…
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▼ Bcl-2 is an anti-apoptotic protein that has recently been shown to regulate other cellular functions. We previously reported the novel function of Bcl-2 that regulates chondrocyte matrix gene expression, independent of its anti-apoptotic function. The first hypothesis was that Bcl-2 regulates chondrocyte phenotype through the specific pathways. The role of three intracellular signaling pathways likely to be associated with Bcl-2 function, namely, NFkappaB, PKCalpha, and ERK1/2, was examined. The NFkappaB and PKCalpha signaling pathways were not involved in Bcl-2 regulated matrix expression, even thought these are known to regulate Sox9. The ERK1/2 signaling pathway was activated in Bcl-2 deficient cells that lost the chondrocyte phenotype by decreasing chondrocyte matrix protein expression and increasing fibroblastic collagen expression. The inhibition of phopspho-ERK1/2 reversed cells to have chondrocyte phenotype. Moreover, the MEK-ERK1/2 pathway limits the gene expression of matrix protein in wild type chondrocytes. These data indicate that Bcl-2 regulates chondrocyte phenotype through the MEK-ERK1/2 pathway. The second hypothesis was that Bcl-2 regulates chondrocyte phenotype in vitro as well as in vivo specifically, in human osteoarthritis. Osteoarthritis (OA) is an age-related degenerative cartilage disease and is known that the chondrocyte phenotype is altered. However, the significance of the altered phenotype in OA is unclear due to the use of non-age match samples, different source of samples, and lack of precise determination of the stage of OA progression. We developed an intrajoint comparison model using human OA samples to control for patient age and genetic background effects. The advanced OA cartilage was taken from within 1cm of overt lesions. In contrast, minimal OA cartilage was taken from areas without any obvious lesions. The chondrocyte matrix protein and Bcl-2 mRNA expression was decreased in advanced OA cartilage compared with minimal OA cartilage in most of patients studied. In contrast, osteopontin mRNA expression was up-regulated in advanced OA cartilage compared with minimal OA cartilage. A correlation was observed between the steady state mRNA coding for aggrecan and Bcl-2, and Bcl-2 and Sox9. These results support the hypothesis that Bcl-2 regulates chondrocyte phenotype in vivo as well as in vitro.
Advisors/Committee Members: Horton, Walter E.
Keywords: Chondrocytes; Osteoarthritis; Sox9; Bcl-2; MEK-ERK1/2
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20.
Yahaya, Azlan R.
Islam Hadhari: An Ideological Discourse Analysis of Selected Speeches by UMNO President and Malaysia Prime Minister Abdullah Ahmad Badawi.
Degree: PhD, Mass Communication (Communication), 2012, Ohio University
► This research study explored the problem the Malay identity and society in…
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▼ This research study explored the problem the Malay identity and society in the discourse of Malay politics. The purpose of this study was to understand how the discourse of Islam Hadhari as spoken by prime minister and UMNO president Abdullah Ahmad Badawi in the years 2004-2008 demonstrated the hegemony of his administration and party. This study assumed that discourses function within society and is only understood in the “interplay of social situation, action, actor and societal structures”(Meyer, 2001, p. 21). The study also assumed ideologies as the social representations that have specific social functions for social groups (van Dijk, 2001). van Dijk (2001) proposed that discourse is privileged in the (re)production of ideologies as, unlike other social practices, properties of text and talk “allow social members to actually express or formulate ideological beliefs” (p. 192). For the purposes of this study, the critical discourse analysis approach of ideological discourse analysis was used to observe the micro level of ideological(re)production being expressed by UMNO President Badawi in speeches. 19 speeches given by Badawi in various communicative events throughout 2004-2008 were selected to infer the ideological discourse of Islam Hadhari, the UMNO ideological approach to Islamism of the Malays, in this study referred to variously as Malay Islamism or Islamist Malayness. The study found that UMNO sought to persuade and influence the divided Malay constituency by engaging PAS in the discourse of the Malay Islamist state through the party ideology of Islam Hadhari. The study advanced two conclusions: First, Malayness is the constant conflict and correspondence with ethnicity and religiosity, Malay and Muslim; and second, a theory of Malay identity should extend to describe Malayness as a civilization, as proposed by Milner (2007).
Advisors/Committee Members: McDaniel, Drew.
Subjects: Asian Studies; Ethnic Studies; Islamic Studies; Linguistics; Mass Communications; Mass Media; Rhetoric; Social Research; South Asian Studies
Keywords: Islam Hadhari; Malay identity; Abdullah Ahmad Badawi; ideological discourse analysis; critical discourse analysis; Malaysia; UMNO; Malay ideology; Malay-Muslim dialectic; Islamist Malayness; Malayness as civilization; Malay Islamist state
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21.
Yahl, Ryan Michael.
Attitudes of High School Band Directors and Students Regarding Ohio Music Education Association Large Group Adjudicated Events.
Degree: MM, Music Education, 2009, Bowling Green State University
► The purpose of this study was to determine attitudes of high school…
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▼ The purpose of this study was to determine attitudes of high school band directors and students regarding Ohio Music Education Association (OMEA) Large Group Adjudicated Events. Subjects were high school band directors (n = 11) and students (n = 214) from 12 bands in OMEA District I, which consists six counties in Northwest Ohio (Defiance, Fulton, Lucas, Napoleon, Williams, and Wood). Subjects represented each of the OMEA performance classifications (AA, A, B, C, and D) and three geographic regions (rural, suburban, and urban). Participants completed the OMEA Large Group Adjudicated Events Survey, which consisted of three sections: (a) background information, (b) personal opinion, and (c) free response. Based on data collected from survey responses, both directors and students agree that Large GroupAdjudicated Events are an important part of high school band programs. Subjects also agree that, although the rating earned at contest is important, making music and receiving comments from adjudicators are of higher importance.
Advisors/Committee Members: Thompson, Kenneth.
Subjects: Music; Music education
Keywords: band directors; band contest; adjudicated events; Ohio Music Education Association; student attitudes
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22.
Yahsi, Sebnem Emine.
Application of the solar energy at Ohio public highway rest areas.
Degree: MS, Civil Engineering (Engineering), 1992, Ohio University
► Solar power as partial source of energy for public highway rest areas…
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▼ Solar power as partial source of energy for public highway rest areas is being evaluated in Ohio. In this study two highway rest areas were instrumented with solar water heating system and monitoring equipment. Results for one of the two instrumented rest areas were monitored over a one year period. The performance of the solar collector and their components were evaluated and economical comparisons made between the conventional system and the solar system using life-cycle cost analysis. In comparison to the conventional system, the solar hot water system was found to be an economical alternative energy source. The results suggest that solar contribution was only 4% in winter but 100% in summer. The emergency lighting provided by a photovoltaic system was enthasiaitically endorsed by rest area personnell. Power usage indicates that the system was over designed.
Advisors/Committee Members: Hazen, Glenn.
Subjects: Engineering, Civil
Keywords: Application of solar energy; Ohio public highway; Rest areas
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23.
Yahsi, Ugur.
Statistical thermodynamics of chain molecular fluids: Equation of state parameters for PVT scaling and their group contributions.
Degree: PhD, Physics, 1994, Case Western Reserve University
► Extensive experimental studies of fluid hydrocarbons in the lubricating range of molar…
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▼ Extensive experimental studies of fluid hydrocarbons in the lubricating range of molar mass have been undertaken sometime ago by American Petroleum Institute Project 42, located in the Departments of Chemistry and Physics at Pennsylvania State University. In these studies systematic structural changes were introduced, so that the equation of state (e.o.s.) as well as the viscosities of linear paraffins, branched hydrocarbons, and various rings attached to n-alkanes tails are known. Hence this material became the basis for various semi-empirical or empirical structural correlations. We proceed here with the hole theory of Simha-Somcynsky (SS) which has proven quantitatively successful for low as well as high molar mass system and examine e.o.s. data. We demonstrate the success of the theory and obtain the characteristic volume (ν*), energy (varepsilon*) and flexibility (c) parameters as functions of chain length for the different structures. For the short chains in question these represent averages over the terminal and internal units. By suitable generalization of the SS theory developed for physical mixtures we decompose these averages into the individual group contributions. The accuracy of the numerical procedures employed is tested by back computations. Sometime ago A. Bondi developed structural rules for the computation of Van der Waals excluded group volumes. Interesting correlations between these and the above ν* values, defined for a 6-12 potential, are obtained. In the same way we examine correlations between D. W. Van Krevelen's and P. J. Hoftyzer's cohesive group energies and varepsilon* values.
Advisors/Committee Members: Simha, Robert.
Keywords: Statistical thermodynamics; chain molecular fluids; state parameters; PVT scaling; group contributions
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24.
Yahsi, Zekiye.
The Village School and Village Life: An Ethnographic Study of Early Childhood Education.
Degree: PhD, EDU Teaching and Learning, 2011, Ohio State University
► This study investigates the forms of social organization found in modern classrooms…
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▼ This study investigates the forms of social organization found in modern classrooms and classroom lessons, as they are encountered by children in a rural Turkish village, in its village school. It is a study of the early childhood education and educational experience of these children. It is composed of a collection of ethnographic descriptions and discourse analyses that examine the social–organizational forms of life found in the village, those found in the school, and the experiences and attitudes of village children, parents and elders towards schooling and its place in their lives. These three foci organize the early childhood educational experiences of these children. They organize a larger picture of their encounters with schooling in the early grades and the place of schooling in the lives of their families. All children develop the competencies required of them as they participate in their routine daily activities with little, if any, direct or explicit instruction. Much of early childhood education is of this implicit, participatory character. The instruction that is implicit to their participation, whether in the classroom community or the village community, is both taken granted, and closely studied by the children. It is in these ways that modern school rooms engage in the production of modern students, among village children.
Advisors/Committee Members: Macbeth, Douglas.
Subjects: Early Childhood Education
Keywords: Early childhood education; Early childhood experience; Village life; Classroom contexts; Ethnography; Classroom discourse analysis; Sequential Analysis
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25.
Yakey, Abigail Brodrick.
COMPARING FOOT PRESSURES DURING FEEDING IN TWO DISTINCT GROUPS OF CHILDREN.
Degree: MA, Speech Pathology and Audiology, 2007, Miami University
► The purpose of this study was to observe typically developing children ages…
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▼ The purpose of this study was to observe typically developing children ages 6 to 18 months during feeding times and to study trends between foot pressures and awake arousal and attention levels. Ten subjects sat in a prototype highchair for three feeding trials and foot pressures were collected. Study results show that the older children exerted more foot pressure for a greater amount of time. Older children also used both feet more consistently when pushing. Future research is needed to determine the effects of foot pressure as a means of self-regulating and transitioning between awake arousal and attention levels.
Advisors/Committee Members: Scarborough, Donna R.
Keywords: children; feeding; foot pressure; arousal and attention levels
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26.
Yakopcic, Chris.
Memristor Devices: Fabrication, Characterization, Simulation, and Circuit Design.
Degree: MS, Electrical Engineering, 2011, University of Dayton
► Significant interest has been placed on developing systems based on memristors since…
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▼ Significant interest has been placed on developing systems based on memristors since the initial fabrication by HP Labs in 2008 [1]. The memristor is a nanoscale device with dynamic resistance that is able to retain the last programmed resistance value after power is removed from the device. This property shows that the memristor can be used as a non-volatile memory component, and has potential to enhance many types of systems, such as high density memory, and neuromorphic computing architectures. This thesis presents the fabrication and characterization results obtained based memristor devices developed at the University of Dayton. In addition, a comparison between the existing memristor device models was completed to show how the memristor can be used in a multistate operation. Lastly, circuit designs were completed that demonstrate the writing and reading of information to and from memristor devices. These represent the initial steps required in developing electronic systems based on memristors. A large portion of the work completed in this thesis has been published in [2-4].
Advisors/Committee Members: Taha, Tarek.
Subjects: Electrical Engineering
Keywords: memristor; memristive; fabrication; characterization; simulation; circuit; modeling; TiO2
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27.
Yakoub, Mohammed Ibrahim.
THE RELATIONSHIP OF DIABETES MELLITUS TO VENTILATOR-ASSOCIATED PNEUMONIA, BLOODSTREAM INFECTION, HEALTH-RELATED QUALITY OF LIFE, AND MORTALITY IN CHRONICALLY CRITICALLY ILL PATIENTS.
Degree: PhD, Nursing, 2008, Case Western Reserve University
► This study examined the relationship of diabetes mellitus to in-hospital and post-discharge…
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▼ This study examined the relationship of diabetes mellitus to in-hospital and post-discharge mortality, risk for developing infections (Ventilator-Associated Pneumonia and bloodstream infection), and health- related quality of life in chronically critically ill patients. Chronically critically ill (CCI) patients, who require prolonged mechanical ventilation after acute illness, represent a growing and distinct group of patients in the health care system. Their poor short- and long-term outcomes are a point of substantial concern. Despite the intensive care they receive, in-hospital mortality and post discharge mortality remain high with no significant change in the last two decades, along with extreme functional dependence among survivors. Decreasing the mortality rate and returning these survivors of chronic critical illness to functional independence and an acceptable quality of life remains a major challenge. Complications are frequent in chronically critically ill patients, either as part of the etiology of the prolonged intensive care unit (ICU) stay or as a risk of prolonged use of invasive technology. Complications of long-term hospital care such as pneumonia and sepsis were identified among the mechanisms associated with ventilator dependence. Examining patients’ characteristics that might lead to developing such complications will help nurses and other clinicians to anticipate or predict which patients will have a complicated pattern of chronic critical illness. The presence of diabetes (history of diabetes) in chronically critically ill patients was hypothesized in this study to have a negative effect on in-hospital and post-discharge (at 2 months) mortality. Results from this study showed that there was not a statistically significant direct relationship between diabetes and in-hospital and post-discharge mortality after adjusting for other study covariates (age, APS scores, pre-existing medical and surgical conditions, LOMV, use of general anesthesia, presence of risk factors (renal dialysis and immunosuppression), development of ventilator-associated pneumonia, and bloodstream infection). With all 9 predictor variables in the equation, the strongest predictor for in-hospital death was the development of a bloodstream infection. The presence of a bloodstream infection increased the likelihood of hospital death by two times. CCI patients in this study had high infection rates. In particular, and as hypothesized, VAP and bloodstream infection were shown to be important factors in the CCI patients in this study and contributed to poor outcomes. This study showed diabetes to be a significant risk factor for VAP and bloodstream (clinical sepsis or laboratory confirmed) infection development. Diabetes was not shown to influence Health-Related Quality of Life in this study. As expected, the strongest predictor was pre-admission Health-Related Quality of life. Length of mechanical ventilation, development of Ventilator-Associated Pneumonia, and Bloodstream infection negatively affected Health-Related Quality of Life- Physical component. Age, on the other hand, had a positive influence on Health-Related Quality of life-Physical component. Prevention of infectious complications is key to helping CCI patients to have a less complicated pattern of illness. Efforts at prevention originate from an improved understanding of the factors associated with the development of such infectious complication. In this study diabetes, as a host-related factor, emerged as a potential risk factor for such infection. Continuous efforts still need to be made to identify patients at increased risk so that appropriate interventions can be proposed to improve quality of care and outcomes in CCI patients.
Advisors/Committee Members: Daly, Barbara J.
Subjects: Health Sciences, Nursing
Keywords: Chronically Critically Ill Patients; Diabetes Mellitus; Ventilator-Associated Pneumonia; Bloodstream Infection
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28.
Yakovich, Adam J.
Old targets and new beginnings: a multifaceted approach to combating Leishmaniasis, a neglected tropical disease.
Degree: PhD, Pharmacy, 2007, Ohio State University
► Leishmaniasis, a broad spectrum of disease which is caused by the protozoan…
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▼ Leishmaniasis, a broad spectrum of disease which is caused by the protozoan parasite Leishmania, currently affects 12 million people worldwide, with over 2 million of new cases occurring annually. There are several clinical manifestations, including visceral leishmaniasis, which attacks the reticuloendothelial system and has a fatality rate near 100% if untreated. All currently available therapies all suffer from drawbacks including expense, route of administration and developing resistance. Tubulin, a heterodimeric protein, comprises microtubules which are critical for eukaryotic cell mitosis. We have previously identified a series of dinitroaniline compounds which inhibit Leishmania growth in vitro by inhibiting tubulin polymerization. These compounds selectively inhibit Leishmania tubulin, indicating it may be a useful chemotherapeutic target. Evaluation of future generations of analogues will require purified Leishmania tubulin. Previously, the pathogenic species L. amazonensis has been used as a tubulin source, however, we have modified the protocol to utilize the non-pathogenic species L. tarentolae. Genetic sequencing and drug activity/affinity assays indicates that L. tarentolae tubulin is a suitable alternative for drug screening. Modeling studies with our compounds bound to Leishmania tubulin suggest the the bind to a previously uncharacterized site on á-tubulin. To confirm this, an attempt was made to acquire a crystal structure of tubulin with our compounds bound. Previously, mammalian tubulin has been crystallized by using the protein stathmin to sequester it in tetramers. Efforts were made to identify and purify a stathmin like protein in Leishmania capable of sequestering tubulin in tetramers. Unfortunately attempts to identify a low molecular weight protein present in Leishmania capable of sequestering tubulin were unsuccessful. In an ever expanding search for novel lead compounds, our lab has recently purchased the ChemBridge CNS set of 10,000 druglike molecules. These compounds were screened against Leishmania donovani axenic amastigotes. The screen of 10,000 compounds revealed 75 compounds which inhibited Leishmania growth by 50% or greater at 10 µM. Of these 75 compounds 17 were found to exhibit at least 25-fold selectivity for inhibiting Leishmania cell proliferation when compared to mammalian Vero cells. The selective compounds will continue to be evaluated in an effort to identify novel lead compounds
Advisors/Committee Members: Werbovetz, Karl A.
Keywords: Leishmania; Leishmaniasis; Kinetoplastid; Tubulin; Microtubule; Stathmin; High throughput screen; Parasite
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29.
Yakubova, Shakhnoza.
PERCEPTION OF QUALITY IN CHANGING UNIVERSITY EDUCATION IN KAZAKHSTAN.
Degree: MA, College and Graduate School of Education, Health and Human Services / School of Foundations, Leadership and Administration, 2009, Kent State University
► This study is designed to describe the perception of quality in higher…
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▼ This study is designed to describe the perception of quality in higher education from both administrative and student perspectives in Kazakhstan. The descriptive qualitative method is used in this research. The purpose of this study is to understand the criteria for university quality during educational reforms in Kazakhstan. The research found limited public access to information in higher education. Besides, it questions the validity of the information, and analyzes the generational difference in attitudes of the participants as well as the differences in perception of quality at upper administrative, institutional and student levels. Furthermore, it defines the major obstacles in educational reform such as mentality of the older generation as well as corruption, lack of academic and financial resources, ignorance of a student voice, limited institutional autonomy, a low salary rate of faculty, lack of practical knowledge, absence of focus on student learning outcomes, and limited academic freedom.
Advisors/Committee Members: Merrill, Martha.
Subjects: Higher education
Keywords: perception of quality; quality assessment; higher education; educational reforms; Kazakhstan; changes in university education
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30.
Yakunina, Elena Sergeeva.
Asian International Students' Intentions to Seek Counseling: Integrating Cognitive and Cultural Predictors.
Degree: PhD, Counseling Psychology, 2012, University of Akron
► Research has consistently identified low rates of counseling use among Asian international…
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▼ Research has consistently identified low rates of counseling use among Asian international students. Empirical findings suggest that Asian foreign students are less likely to seek counseling than their American peers (Huyn, Quinn, Madon, and Lustig, 2007; Nilsson, Berkel, Flores, and Lucas, 2004; Yakushko, Davidson, and Sanford-Martens, 2008). Research also indicates that when Asian international students do seek counseling, they typically attend few therapy sessions (Nilsson et al., 2004; Yakushko et al., 2008). Several calls have been made to examine different cognitive and cultural predictors of counseling use in this population (Heggins and Jackson, 2003; Ibrahim and Ingram, 2007; Mori, 2000; Sheu and Fukuyama, 2007). Possible cognitive predictors include help-seeking intentions, counseling attitudes, and stigma concerns. Potential cultural predictors include acculturation, Asian values, and loss of face concerns. The purpose of this study was to integrate the above predictors using the Theory of Reasoned Action (TRA, Ajzen and Fishbein, 1980; Fishbein and Ajzen, 2009). In order to test the applicability of the TRA, data were collected from 295 Asian international students. All participants completed an online survey including a demographic questionnaire and measures of help-seeking intentions, counseling attitudes, stigma concerns, acculturation, Asian values, and loss of face concerns. Subsequently, three TRA models were tested: a Non-Mediated, a Partially Mediated, and a Fully Mediated Model (Holmbeck, 1997). Additional analyses included bivariate correlations and bootstrapping analysis of indirect effects (Shrout and Bolger, 2002). The results indicated partial support for the TRA as an integrated model of Asian international students’ help-seeking. Path analysis indicated that the Partially Mediated Model offered the best data fit. In addition, participants’ endorsement of Asian values was associated with more negative counseling attitudes, which then resulted into lower help-seeking intentions. Contrary to the hypotheses, however, acculturation did not predict any of the help-seeking constructs of interest. In addition, participants’ stigma and loss of face concerns were positively associated with their help-seeking intentions, which is inconsistent with prior theory and research. Overall, the findings of the present study indicate that Asian international students’ help-seeking intentions may be more complex than what is represented by the TRA.
Advisors/Committee Members: Weigold, Ingrid.
Subjects: Counseling Psychology
Keywords: help-seeking; counseling; Asian and Asian American populations; international students
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