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Chan, XinniSurvival Processing Effect on Memory for Social Information
Doctor of Philosophy, University of Toledo, 2017, Psychology - Experimental
Recent research has suggested that our memory systems have evolved to prioritize processing information that enhances our fitness (e.g., location of food, distance of predators). In a provocative line of research, a number of studies have shown that people who merely think about survival demonstrate enhanced recall for word lists compared to those in control conditions who think about non-survival topics (e.g., Kang, McDermott, & Cohen, 2008; Nairne, Thompson, & Pandeirada, 2007; Weinstein, Bugg, & Roediger III; 2008). Researchers have attributed this to an evolved sensitivity to fitness-relevant content, which enhances attention and memory processes when prompted to think about survival contexts. More recent research has suggested cognitive explanations rather than evolutionary motives, such as encoding stimuli in ways that are congruent with the context, explain these effects (Butler, Kang, & Roediger III, 2009). To date, nearly all tests of the survival processing advantage have been conducted in non-social domains involving word lists and no study has assessed the functional value of the survival processing advantage for outcomes other than memory, such as judgments and decisions. Given the proximal role of social information in modern and ancestral life, this dissertation tested between evolutionary and cognitive explanations (i.e., a congruency-incongruency account) of the survival processing advantage for social memory and judgments/decisions. After establishing the appropriateness of stimuli in a pilot study, participants in the main study were randomly assigned to read one of two scenarios: a survival scenario where participants imagined being stranded in foreign grasslands or a non-survival scenario where they imagined leading the robbery of a well-guarded bank. As part of the task, participants were told that they needed to connect with other social groups to assist in meeting the scenario goal, wherein information about four social groups were presented. Critically, the groups possessed different numbers of characteristics that were congruent or incongruent with survival and leading a robbery. The main dependent measures were recall and recognition of the group characteristics and the accuracy of participants’ decisions and judgments about the groups (e.g., whether they decided to join the group possessing the most goal-relevant traits). Overall, the results more clearly supported the congruency-incongruency account than the survival processing account. First, participants recalled social traits best when the traits were congruent with the scenario context, regardless of whether it was a survival or robbery context. However, recognition did not differ as a function of condition or trait type. Second, participants in the robbery and survival conditions chose the “correct” group at equivalent and greater-than-chance levels and judged groups with the most goal-relevant traits more favorably than groups with the least goal-relevant traits. This latter set of results suggests that participants used the scenario context in a functional way to guide their judgments and decisions. Implications for several different research literatures are discussed.

Committee:

Jason Rose (Committee Chair); Yueh_Ting Lee (Committee Co-Chair); Daniel Kruger (Committee Member); Andrew Geers (Committee Member); Revathy Kumar (Committee Member)

Subjects:

Psychology

Keywords:

Survival Processing Effect; Memory; Social Information; Evolutionary Motive; Congruent-incongruent

Clos, Timothy GeorgeCompactness of Hankel Operators with Continuous Symbols on Domains in ℂ2
Doctor of Philosophy, University of Toledo, 2017, Mathematics
This thesis will present original work characterizing compactness of Hankel operators with continuous symbols on the Bergman spaces of bounded convex Reinhardt domains in ℂ2. We assume no boundary regularity or symbol regularity other than continuity of the symbol up to the closure of the domain.

Committee:

Sonmez Sahutoglu, Ph.D (Committee Chair); Zeljko Cuckovic, Ph.D (Committee Member); Trieu Le, Ph.D (Committee Member); Akaki Tikaradze, Ph.D (Committee Member); Yunus Zeytuncu, Ph.D (Committee Member)

Subjects:

Mathematics

Keywords:

Several complex variables;

Bafakeeh, Omar TMicro/Nano Surface Finish Single Side Electrolytic In-Process Dressing (ELID) Grinding with Lapping Kinematics of Sapphire
Doctor of Philosophy, University of Toledo, 2017, Industrial Engineering
The demand for Sapphire ( a-AL2 O3 ) has increased significantly, due to its excellent reliable properties. Sapphire, known for its high hardness and brittleness, has excellent optic, mechanical, and physical properties. Sapphire is used in many different applications such as aerospace, optics, electronics, and in other industries. Machining of sapphire is challenging due to its high hardness and brittleness. The manufacturing of such material is very expensive because the tool wear is very high and longtime machining. Single side grinding is sometimes preferable over conventional grinding because of the ability to provide flat surfaces for ceramic materials. The use of electrolytic in-process dressing (ELID) helps reduce machining time. The use of the kinematics of lapping with the ELID will help reduce machining time in addition to eliminating the use of lapping and polishing. This current study examines five parameters with three levels each. A full factorial design, for both roughness (Ra) and material removal rate (MRR) are be conducted to present mathematical models which predict future results. Three grinding wheels with different mesh sizes are be used. The influence of the grain size on the result will be investigated. The kinematics of the process will be investigated based on the effect of different eccentricities. The parameters used in this study are; different wheel mesh sizes, different pressures, different eccentricities, different spindle speed, and different wheel speed ratios; each of these parameters are in three levels.

Committee:

Ioan Marinescu (Committee Chair); Abdollah Afjeh (Committee Member); Mansoor Alam (Committee Member); Sarit Bhaduri (Committee Member); Matthew Franchetti (Committee Member)

Subjects:

Industrial Engineering; Mechanical Engineering

Keywords:

ELID, Single Side Grinding, Fine Grinding, Sapphire

Lawson, Monica L. The Reliability of Children’s Event Reports to Their Mothers
Doctor of Philosophy, University of Toledo, 2016, Psychology - Experimental
Children involved in maltreatment investigations often discuss allegations with their mothers before formal reports are made to authorities. The primary purpose of the current study was to evaluate the amount and the accuracy of information children reported to their mothers about a non-shared experience. Children aged 4- to 7-years-old (N = 142) individually participated in a staged event and discussed the experience with their mothers approximately six-days later. Prior to interviewing children, mothers were provided with some details about the non-shared event. Accurately-biased mothers had accurate information about the event. Inaccurately-biased mothers had both accurate and inaccurate information about the experience. Individual difference factors including children’s age, maternal reminiscing style, and attachment quality were hypothesized to moderate the relationship between maternal bias and children’s reports. The results revealed older children had highly reliable reports regardless of maternal bias or maternal reminiscing style. However, younger children with inaccurately biased and high elaborative mothers reported less accurate and more inaccurate information about the event compared to younger children with inaccurately-biased and low elaborative mothers. Additionally, children of mothers with insecure attachment quality reported fewer details and made more inaccurate statements regarding the event. Results suggest that the mnemonic consequence of discussing past experiences with mothers varies depending on maternal bias, children’s age, maternal reminiscing style, and attachment quality. Forensic and theoretical implications of the findings are discussed.

Committee:

Kamala London, PhD (Committee Chair); Stephen Christman, PhD (Committee Member); Sarah Francis, PhD (Committee Member); Jason Rose, PhD (Committee Member); Lisa Pescara-Kovach, PhD (Committee Member)

Subjects:

Developmental Psychology; Psychology

Keywords:

Children; Eyewitness testimony; Maternal reminiscing style; Attachment; Suggestibility

Miranda, Michael AngeloBio Based Active Barrier Materials and Package Development
Doctor of Philosophy, University of Toledo, 2016, Chemical Engineering
The food and packaging industries are interested in approaches to reduce the permeability of oxygen in polyethylene terephthalate (PET) to extend the shelf-life of product. This has led to considerable research in barrier improvement including the use of active scavenger that permanently bind oxygen. The purpose of this work is to investigate the use of renewably sourced unsaturated fatty acids as scavengers to reduce the O¬2 permeability in PET. Specifically fatty acids were characterized and incorporated within PET using both blended and reactive extrusion to analyze the impact on thermal-mechanical and oxygen transport properties. Oleic, linoleic and linolenic acid are renewably resourced unsaturated fatty acids that are being investigated as active scavenger. Utilization of scavenger capacity and kinetics of oxidation are two key parameters that must be considered while selecting a scavenger. The O¬2 uptake capacities and the utilization of scavenger sites analysis were used to determine the most appropriate scavenger used to make a copolymer with PET. Linoleic acid was chosen due to its higher utilization capacity and relatively fast kinetics the cost was also taken into account. Thus linoleic acid was used in preparation of PET/Scavenger system. The effect of addition of unsaturated fatty acid on the thermal, mechanical properties and morphology of PET, were analyzed by preparing blends of PET/linoleic acid of loading of (0.25-2 weight %). The presence of the scavenger were analyzed using end group analysis where an increase in carboxyl end group was determined and NMR to obtain the peaks for the fatty acid. The appropriate method to determine molecular weight was also established. Effects of permeation through amorphous and biaxial oriented films with and without linoleic acid were investigated. The bottles were produced in two different ways (i) reactive extruded bottle and (ii) blended bottles (0.5% weight loading of Linoleic acid). The mechanical properties and density of the bottles were similar. The oxygen permeability of these bottles side wall was lower than that of PET. NMR on sample that has been exposed to oxygen was conducted to confirm the reactivity of linoleic acid with oxygen.

Committee:

Maria Coleman (Committee Chair); Saleh. A. Jabarin (Committee Co-Chair); Sridhar Vimajala (Committee Member); Yakov Lapitsky (Committee Member); Young- Wah Kim (Committee Member)

Subjects:

Chemical Engineering; Gases; Packaging; Polymers

Tebbe, Hope MEvaluation of Indoor Air Quality in Four Nursing Home Facilities in Northwest Ohio
Master of Science in Occupational Health, University of Toledo, 2017, Occupational Health (Industrial Hygiene)
Indoor air quality (IAQ) is considered one of the top five environmental risks to the public’s health. Older adults are more vulnerable to health complications associated with indoor air contaminants because of their decreased immune system and age-associated health problems, as well as the fact that they spend up to 95 percent of their time indoors. Area air sampling was conducted in the nursing home section of four long term care facilities, three days at each facility (12 days total). Particle concentrations (PM2.5, PM10, Total Particulate matter (TPM), Ultrafine Particles (UFP), temperature, and humidity were measured. Two minute samples were collected during seven Sampling Sessions. Up to nine indoor locations were sampled, representing the various occupied spaces in each nursing home, along with an outside location for comparison. Results of Analysis of Variance (ANOVA) by Facility demonstrated significant differences (p<0.001) in PM concentrations and UFP counts. One Facility had higher particulate concentrations at all Sampling Locations which may include contributions from geographic location, vehicular traffic, or resident clustering. ANOVA by Sampling Location demonstrated significant differences (p<0.001) in PM concentrations and UFP counts. In general, the highest UFP and PM concentrations were seen in the kitchen, satellite kitchen, and hair salon, especially at times when the staff and residents were active in these rooms. Significant differences were seen in UFP counts (Facilities 1 and 3) and PM2.5 (Facility 2) by Sampling Session. The highest concentrations were found for the Sampling Sessions in the mid-morning and mid-afternoon which were during peak times of activity for the residents. Although maximum temperature measurements exceeded ASHRAE winter guidelines, this may be appropriate for older residents who prefer a warmer temperature. While most median particle values were below ASHRAE guidelines, maximum values did exceed occasionally in the hair salon and kitchen at all facilities. Various indoor Sampling Location PM concentrations or UFP counts exceeded the outdoor levels at all four facilities. Although the median PM values did not exceed the ASHRAE standards it is unknown whether older adults may still experience significant health complications with these PM concentrations. In addition staff who spend extended amount of times in the kitchen and hair salon could be exposed to higher levels of PM. IAQ in hospitals and similar environments, such as nursing homes, may require a higher level of care because of the vulnerable population.

Committee:

April Ames, PhD, CIH (Committee Chair); Victoria Steiner, PhD (Committee Member); Akbar-Khanzadeh Farhang, PhD, CIH (Committee Member); Sheryl Milz, PhD, CIH (Committee Member)

Subjects:

Aging; Alternative Medicine; Engineering; Environmental Engineering; Environmental Health; Environmental Science; Environmental Studies; Gerontology; Health; Health Care Management; Health Sciences; Medicine; Occupational Health; Occupational Safety; Public Health; Welfare

Keywords:

Particulate Matter; Nursing Homes; Elderly; Indoor Air Quality; PM; IAQ; ASHRAE; Air Quality; susceptible population; buildings; Aging

Nabiyouni, NasimA Lean Six-Sigma Approach to Red Bag Waste Management in Hospitals
Master of Science, University of Toledo, 2016, Engineering
Lean Six-Sigma methodology is an approach to improve value streams in term of meeting customer desire by elimination waste and defect. This method is a combination of lean thinking and Six-Sigma. Lean thinking provides an integrated overlook tool to business operations to perform more coherent technologies and assets flow instead of focusing to improve separate departments. Six-Sigma improves quality by decreasing the number of defects. The objective of this thesis is to eliminate errors in Regulated Medical Waste specifically red bag wastes. In order to achieve the goal of the research, lean six-sigma application in healthcare, a full process analysis of red bag waste in hospitals (including human factors), and an economic-environmental impact study of red bag waste and minimization methodology has been studied. Red bag waste is one type of regulated medical waste (RMW), also known as `biohazardous’ waste or 'infectious medical’ waste. This portion of the waste stream by definition is contaminated by blood, body fluids or other potentially infectious materials. In case of improper management, significant risk of transmitting infection would threaten the public heat and environment. In order to prevent confusion and mistakes in discarding these wastes, specified regulations and guidelines are developed. Each category of regulated medical waste has special handling requirements that may be state-specific. This thesis reveals the current red bag waste problems in an existing healthcare facility, a hospital in Toledo, Ohio. The study develops a universal model for improving red bag waste management value stream and focuses on human factors as key elements to improvement.

Committee:

Mathew Franchetti, Prof (Committee Chair); Kumar Ashok, Prof (Committee Member); Spivak Alex, Prof (Committee Member)

Subjects:

Engineering; Health Care Management

Keywords:

Lean, Six-Sigma, Lean in Healthcare, Red Bag Waste Management, Medical Waste Management

Dhar, SamirAddressing Challenges with Big Data for Maritime Navigation: AIS Data within the Great Lakes System
Doctor of Philosophy, University of Toledo, 2016, Spatially Integrated Social Science
The study presented here deals with commercial vessel tracking in the Great Lakes using the Automatic Identification System (AIS). Specific objectives within this study include development of methods for data acquisition, data reduction, storage and management, and reporting of vessel activity within the Great Lakes using AIS. These data show considerable promise in tracking commodity flows through the system as well as documenting traffic volumes at key locations requiring infrastructure investment (particularly dredging). Other applications include detecting vessel calls at specific terminals, locks and other navigation points of interest. This study will document the techniques developed to acquire, reduce, aggregate and store AIS data at The University of Toledo. Specific topics of the paper include: data reducing techniques to reduce data volumes, vessel path tracking, estimate speed on waterway network, detection of vessel calls made at a dock, and a data analysis and mining for errors within AIS data. The study also revealed the importance of AIS technology in maritime safety, but the data is coupled with errors and inaccuracy. These errors within the AIS data will have to be addressed and rectified in future to make the data accurate and useful. The data reduction algorithm shows a 98% reduction in AIS data making it more manageable. In future similar data reduction techniques can possibly be used with traffic GPS data collected for highways and railways.

Committee:

Peter Lindquist (Committee Chair); Kevin Czajkowski (Committee Member); Neil Reid (Committee Member); Mark Vonderembse (Committee Member); Richard Stewart (Committee Member)

Subjects:

Geographic Information Science; Geography; Information Technology; Remote Sensing; Social Research; Transportation

Keywords:

Automatic Identification System , AIS, Big Data, Data Reduction Technique, Vessel Path, Vessel Call, Great Lakes, Maritime, VTS

Esakov, EmilyCharacterization of a Novel Pre-Diabetic Murine Model for Type 1 Diabetes
Doctor of Philosophy, University of Toledo, 2016, Medicinal Chemistry
It has been shown in the non-obese diabetic (NOD) mouse model that type 1 diabetes (T1D) is an autoimmune disease characterized by insulitis and T cell-mediated destruction of pancreatic islet beta cells. The insulin receptor (IR) is a chemotactic receptor capable of driving T cell movement in response to insulin. To this end, characterizing IR expression is of key importance for understanding the pathogenesis of diabetes. T cells may be driven to infiltrate pancreatic islets due to a high level of IR on their surface. The purpose of this project is to phenotype the transgenic BL/6-CD3FLAGmIR (non-diabetic) mouse model to better understand the role of increased IR on the CD3+ T cell surface in relation to pancreatic insulitis. This animal model shows onset of insulitis, but animals do not become diabetic making them an efficient model to study trafficking of CD3+ T cells from the spleen to the pancreas as the altered T cells are FLAG tagged. If IR expression is established as a mechanism to move T cells into islets, then down regulation or blocking of IR expression specifically in T cells will provide a new therapeutic target to block cell movement into the pancreas, thus preventing T1D.

Committee:

Marcia McInerney (Committee Chair); Katherine Wall (Committee Member); Hermann Von Grafenstein (Committee Member); Andrea Kalinoski (Committee Member)

Subjects:

Immunology; Pharmacy Sciences

Ariss, Laila DianeDifferentiated Instruction: An Exploratory Study in a Secondary Mathematics Classroom
Doctor of Philosophy, University of Toledo, 2017, Curriculum and Instruction: Secondary Education
This case study explores the different approaches to teaching inside a differentiated instruction classroom. The research will be conducted at a college preparatory high school with an emphasis on using various approaches to differentiated instruction to enhance students’ comprehension of Advanced Algebra II. Data collection will include students’ journal reflections, direct-observations, participant-observations, lesson plans, physical artifacts, various students’ assessments, and survey-interviews. The study followed a mixed method design and consisted of two parts qualitative and quantitative data collection and analyses. Both data will be analyzed using excel sheets and ATLAS.ti software. In addition to studying the effects of differentiated instruction on the teacher, the focus of this study will be on mathematics differentiated instruction classroom and how the researcher will relate students’ experience in class to the quantitative outcome of the data.

Committee:

Leigh Chiarelott (Committee Chair); Debra Johanning (Committee Member); Berhane Teclehaimanot (Committee Member); Victoria Stewart (Committee Member)

Subjects:

Curricula; Curriculum Development; Education; Educational Theory; Higher Education; Instructional Design; Mathematics; Mathematics Education

Keywords:

Differentiated Instruction;Mathematics Classroom;Learning style;Learning Profile;Content;Assessment; Process;Product;ATLAS-ti;Quantitative Research;Qualitative Research;Mixed Method Approach;Data;Frequency Table;Median;Data Analysis;Instructional Strategy

Salem, Nada MUnderstanding Humor, Expressions, Profanity, and Cartoons in a Bilingual and Bi-Cultural Context
Master of Arts and Education, University of Toledo, 2017, English (as a Second Language)
This study examines whether different personal attributes could affect our understanding and interpretation of concepts that are foreign to us due to linguistic or cultural reasons. The attributes in question in this research are religion, gender, educational level, and native language of the subjects. A seven-question survey is used to inquire about these features, and based on the answers, a pool of participants is randomly selected. The core of the study consists of a questionnaire based on four sections. The first contains expressions pertaining to the Arab culture, the second has expressions that reflect American culture. The third and the fourth sections comprise respectively profanity and vulgarity expressions and cartoons all familiar to American culture. The sample I select for testing represents the different attributes mentioned above and spreads across three groups: native English speakers, native Arabic speakers, and non-native English or Arabic speakers (like Latinos, Indians and Asians). This research is conducted partly at the University of Toledo with participants who work or study there, and the other part is within the Toledo area, with participants who are friends and acquaintances from the Toledo Arab community. The data I collect is tested statistically to find out if there is any correlation or difference between the properties of my participants with the answers they choose on their questionnaires. Finding whether there is a correlation or not or a difference or not aids in finding out if the participants’ attributes had altered their interpretation and understanding of each section. The statistical results showed that most of these attributes had no correlation and showed no difference by the participants’ responses. The only two attributes that showed some correlation or difference were educational level and native language. I hope that my findings can be helpful to future research aimed for the betterment of second language acquisition strategies of instruction by showing what attributes should be focused on in making those strategies more effective and practical. My suggestion for future research is to study a much larger sample and look for interactions among variables specific to the sample.

Committee:

Douglas Coleman (Committee Chair); Samir Abu Absi (Committee Member); Gaby Semaan (Committee Member)

Subjects:

Education; English As A Second Language

Keywords:

Cartoon, Arabic expressions, Profanity, English expressions, Bi- cultural, Bilingual, interpretation,

Stanley , Wendy LAn Exploratory Case Study of How a Professional Learning Community is Being Implemented in an Elementary School from the Perspective of the Teachers
Doctor of Philosophy, University of Toledo, 2017, Curriculum and Instruction
An Abstract of An Exploratory Case Study of How a Professional Learning Community is Implemented in an Elementary School from the Perspective of the Teachers by Wendy L. Stanley Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Curriculum and Instruction The University of Toledo May, 2017 The purpose of this qualitative research was to use a case study methodology to explore and describe in detail the process the teachers and support staff followed to implement a professional learning community in their elementary school. There has been little research on the how professional learning communities emerge and are implemented initially from an educators perspective. The three research questions that were addressed in this study were: (1) How do teachers describe their experiences as they transition from traditional professional development to a professional learning community, (2) What is the process the teachers and staff followed to implement the professional learning community model at Indian Trail Elementary School (ITES), (3) Does this process represent the conceptual framework for professional learning communities? The analysis of the teachers and support staffs’ experiences provides a deep and rich description of the journey the teachers and staff undertook during the transformation of the professional learning community in their school. It provides information on how the teachers and support staff embraced the concepts and practices, and launched a new professional learning community in their school with the entire staff. The main contribution of this study is the finding that the teachers and support staff were able to develop, implement, and transform their elementary school into a professional learning community through the use of three different resources: (1) the DuFour et al., professional learning community model, (2) the Solution Tree Conference, and (3) the summer course with a knowledgeable instructor.

Committee:

Leigh Chiarelott, PhD (Committee Chair); Mark Templin, PhD (Committee Member); Edward Janak, PhD (Committee Member); Casey Reason, PhD (Committee Member)

Subjects:

Curricula; Curriculum Development; Early Childhood Education; Education; Educational Leadership; Teaching

Keywords:

Professional Learning Communities

Wernert, Sean PatrickThe Socio-ecological Influences of College Bullying Behavior: A Phenomenological Study of Student Perceptions
Doctor of Philosophy, University of Toledo, 2017, Educational Psychology
Using Urie Bronfenbrenner’s socio-ecological model of development as a theoretical framework, the purpose of this qualitative, phenomenological study was to examine how college students perceive and understand the bullying phenomenon— as well as the influences and consequences— on campus at University X; a private, religiously affiliated, large, research university. A total of fifteen students representing each undergraduate academic class and college at University X were interviewed using a single interview protocol. The semi-structured interview consisted of open-ended questions allowing the participants to describe their own understanding and perceptions of what constitutes bullying as well as what they perceive to be its influences and consequences. Using a constant comparative analysis of transcribing, coding and analyzing the interviews, the researcher found that college students at University X closely define bullying in the same way research has but exclude the concept of repetition from their understanding. In addition, the participants understand all four forms of bullying— physical, verbal, relational, and cyber— as bullying behavior, but see only verbal and relational forms as the primary types on campus. Participants also primarily understand immediate micro-system and cultural macro-system influences—including the 2016 U.S. election of President Donald Trump—as impacting bullying behavior. Recommendations for prevention and intervention methods are also discussed.

Committee:

Lisa Pescara-Kovach, Ph.D. (Committee Chair); Gregory Stone, Ph.D. (Committee Member); Robert Salem, J.D. (Committee Member); Florian Feucht, Ph.D. (Committee Member)

Subjects:

Behavioral Psychology; Developmental Psychology; Education; Educational Leadership; Educational Psychology; Educational Sociology; Higher Education; Higher Education Administration

Keywords:

bullying; college student behavior; ecological development

Baker, JessicaPerceptions of World Englishes
Master of Arts, University of Toledo, 2017, English (as a Second Language)
This study looks at how native speakers of English respond to different World Englishes compared to non-native English speakers. Also, it looks at whether people who have more experiences with travel or languages have more positive attitudes towards World English speakers and if they were able to know where a speaker is from. Four native and four non-native participants (eight in total) who were Composition I students were interviewed. Four recordings of various World Englishes were used and participants were asked about their attitudes towards the Englishes. This study found native and non-native participants do not have different attitudes towards World Englishes. It also found that experience did not affect attitudes or abilities identifying World English speakers.

Committee:

Melinda Reichelt (Committee Chair); Anthony Edgington (Committee Member); Muchun Yin (Committee Member)

Subjects:

English As A Second Language; Linguistics

Keywords:

World Englishes

Ingels, Marcel LMechanics of Patellofemoral Maltracking in Total Knee Arthroplasty: A Finite Element Analysis
Master of Science, University of Toledo, 2016, Bioengineering
The patellofemoral joint is a complex joint that accounts for a large percentage of knee problems both in knee arthroplasty and in intact knee mechanics. In the United States alone, a 673% increase in primary total knee arthroplasty surgeries performed per year is projected to occur by 2030 (i.e., 3.48 million procedures). Consequently, the total revision rate per year is also projected to increase by 601% by 2030 (i.e., 268,200 revisions). Complication of the patellofemoral joint, associated with the patella maltracking, is one of the most common reasons for revisions in total knee arthroplasty and anterior pain of the intact knee. Thus, understanding patellofemoral maltracking mechanics and its associated risk factors is necessary. This study developed a validated finite element model of an intact knee to compare with instrumented knee patellar mechanics. The biomechanics of a maltracking patella are complex and have been shown to be associated with patellar subluxation, increased Q-angle, and increased external tibial rotation. These risk factors were applied individually and in combination to both an intact knee model and a knee instrumented with a total knee arthroplasty system to observe their effect on patellar mechanics. Thecombination of risk factors resulted in a worst-case maltracking model that was instrumented with a translating patellar implant with the goal of improving patellofemoral mechanics under maltracking conditions. The results of this study showed that the worst occurrence of patellar maltracking occurs because of a combination of various risk factors, such as patellar subluxation, increased Q-angle, and increased external tibial rotation for both intact and instrumented knees. Of these risk factors, the former contributes substantially more toward inducing non-physiological patellar mechanics than the latter two. Among the kinematic indicators for patellar maltracking in intact knees, medial/lateral patellar translation and tilt were ideal, whereas patellar rotation, although provided valuable insight on the patellofemoral joint kinematics, failed in showing any trend toward patellar maltracking. Among the kinematic indicators for patellar maltracking in instrumented knees, medial/lateral patellar translation was ideal, whereas patellar tilt and rotation, although provided valuable insight on the patellofemoral joint kinematics, failed in showing any trend toward patellar maltracking. Nevertheless, implant designers and clinicians should consider the rotation and tilt of the patella under various physiological conditions as design inputs for devices and conservative treatments. Lastly, the results of this study were used in designing a translating patellar implant that showed to reduce the risk of patellar maltracking, corroborating the value of aforementioned trends and kinematic indicators.

Committee:

Vijay Goel, PhD (Committee Chair); Anand Agarwal, PhD (Committee Member); Ronald Fournier, PhD (Committee Member)

Subjects:

Biomedical Engineering

Porter, Audree ElizabethEffective Topical Delivery of Ibuprofen through the Skin
Master of Science in Pharmaceutical Science (MSP), University of Toledo, 2016, Pharmaceutical Sciences (Industrial Pharmacy)
The ability to effectively deliver non-steroidal anti-inflammatory drugs (NSAIDs) topically and transdermally offers an increased localization of the drug to the site of pain and inflammation, while simultaneously reducing systemic absorption. This ultimately results in more effective treatment for localized pain and inflammation, while reducing the undesired side effects associated with NSAIDs. In this work, effective topical delivery was studied, specifically to compare and contrast the effects of three separate penetration enhancers utilizing in vitro Franz cell testing methods. Ten formulations, using three different penetration enhancers (Kollicream OA, Kollicream IPM and Kollicream 3C) and two different active pharmaceutical ingredients (ibuprofen and sodium ibuprofen), were tested and results are given in this report. Ultimately, the penetration enhancers were found to impede delivery of active pharmaceutical drugs into the epidermis of the skin over an 8-hour period as compared to a standard blank cream run concurrently. Kollicream 3C was shown to have the best release profile over the initial first hour of the study, mimicking the initial application of the pharmaceutical product. Kollicream OA was shown to have the best release profile over the entire 8-hour period.

Committee:

Kenneth Alexander, Ph.D (Committee Chair); Gabriella Baki, Ph.D. (Committee Member); Marcia McInerney, Ph.D. (Committee Member)

Subjects:

Pharmaceuticals

Keywords:

Penetration Enhancer; Ibuprofen; Topical Drug Delivery

Penumatsa, GowthamCorrosion Detection in Reinforced Concrete Using Acoustic Emission Technique
Master of Science, University of Toledo, 2016, Civil Engineering
Corrosion of reinforcing steel is the major cause for deterioration of concrete structures. Corrosion of these steel bars potentially reduces the service life and ductility of the structures causing early failure of structure, this involves signifi cant cost for inspection and maintenance. Early detection of corrosion is necessary for the proper diagnosis and effective prevention of failure. Therefore, damage induced due to corrosion of reinforcing steel should be detected in the early stages and the severity of corrosion should be properly anticipated by means of non-destructive testing techniques for the safety of the structure. The available methods of corrosion detection in concrete structures are generally electrochemical, such as half-cell potential (HCP) measurements and linear polarization resistance (LPR). These methods are intrusive as they require a physical connection to the corroding steel. Furthermore, these methods only provide information about local corrosion and are usually used after corrosion damage is discovered visually. Acoustic emission is sensitive enough to be a feasible nondestructive testing technique to detect early corrosion. Therefore a corrosion monitoring cell to detect corrosion in reinforced concrete beams using acoustic emission is setup for the rst time at The University of Toledo and experiments are conducted. This thesis presents the fi rst use of acoustic emission to detect corrosion in rein- forced concrete at The University of Toledo. The tasks accomplished includes setting up a corrosion cell and understanding the AE hardware and software equipment. A literature review of corrosion monitoring in reinforced concrete using acoustic emission technology is provided in order to understand the AE technology advancement to date. Corrosion monitoring experiments were designed in the laboratory to initiate corrosion in reinforced concrete in a short time span and continuously monitor with an AE data acquisition system. Electrochemical half-cell potential method is used to anticipate the initiation of corrosion and to correlate AE data with potentials at di fferent stages of the experiment. Steel rebar and two reinforced concrete beams are corroded immersing in 3.5% NaCl solution and using constant potential. The corrosion in these rebar and concrete specimens are monitored continuously using Mistras Pocket Corpac with R15 sensors. Half cell potential measurements are also conducted to understand the method and used to establish correlation with AE. The experiments conducted helped to understand the corrosion process and detect corrosion using AE. The results of the experiments using acoustic emission were found consistent with those in the literature and the conclusions were con rmed using half- cell potential measurements.

Committee:

Douglas Nims (Advisor); Liangbo Hu (Committee Member); Dong Kim (Committee Member)

Subjects:

Civil Engineering; Engineering

Walsh, SeanPerformance-Based Assessment of Oral Dependency within a Forensic Inpatient Mental Health Population
Doctor of Philosophy, University of Toledo, 2016, Psychology - Clinical
The impact of interpersonal dependency can be easily overlooked in clinical and forensic populations despite significant associations with elevated risk for physical illness, suicidality, and functional impairment (Bornstein, 2012). While many measures of interpersonal dependency have been developed and validated across a wide range of clinical populations, there has been minimal research regarding measures appropriate for forensic inpatient mental health populations. The Oral Dependency Language (ODL) scale from the Rorschach Performance Assessment System (R-PAS; Meyer, Viglione, Mihura, Erard, & Erdberg, 2011) is a widely used and validated performance-based measure of interpersonal dependency, but only one published study has used this scale in a forensic population. The present investigation evaluates how dependency needs might manifest within a forensic inpatient mental health population by comparing ODL scores from 88 patients admitted to a maximum security forensic psychiatric facility with ratings of uncooperativeness and passive social withdrawal from the Positive and Negative Syndrome Scale (PANSS; Kay, Fiszbein, & Opler, 1987), a clinician-rated measure of symptoms associated with schizophrenia.Significant negative correlations between ODL scores and the uncooperativeness and passive social withdrawal PANSS items were anticipated but not found. Second, this study also attempted to replicate past research showing a relationship between dependency and physical illness (Bornstein, 1998), with significant positive correlations being expected but not found. Finally, analyses attempted to (a) replicate past research identifying elevated levels of dependency in non-violent pedophiles and sexual homicide perpetrators and (b) extend this research by looking at the relationship between dependency and instant offenses that capture manifestations of orality. Significant positive correlations were hypothesized for both of these analyses but were not found. Lack of construct fit with PANSS variables, method of measurement for assessing dependency, the influence of psychosis on instant offenses, and unique manifestations of dependency in a forensic inpatient mental health population with patients experiencing psychosis are discussed as possible reasons for the lack of significant results for the current study.

Committee:

Joni Mihura, Ph.D. (Committee Chair); Gregory Meyer, Ph.D. (Committee Member); Wesley Bullock, Ph.D. (Committee Member); Jason Rose, Ph.D. (Committee Member); Nicole Kletzka, Ph.D. (Committee Member)

Subjects:

Clinical Psychology; Psychological Tests; Psychology

Keywords:

Dependency, Rorschach, R-PAS, Schizophrenia, PANSS, Forensic, Assessment

Sigdel, PawanImproving Design Strategies for Composite Pavement Overlay: Multi-layered Elastic Approach and Reliability Based Models
Doctor of Philosophy, University of Toledo, 2016, Civil Engineering
Pavements need constant rehabilitation when they deteriorate with time and approach the end of their expected service lives. Overlay is the most prevalent treatment that restores its desirable condition and extends its life span of serviceability, especially for roads subjected to moderate and heavy traffic. Overlay composite design remains a major challenge due to difficulties in characterizing the complex behavior and assessing the existing condition of a combination of asphalt concrete (AC) and Portland cement concrete (PCC) layers over a soil subgrade. Deflection based design using falling weight deflectometer (FWD) deflection data offers an effective approach for overlay thickness design for composite pavements. It utilizes the deflection measurements of the pavement surface which can be used to back-calculate the subgrade and overlay composite properties and allows one to estimate the structural capacity of the existing pavement. However, the prevailing deflection based design procedure generally treats the AC and PCC as a single layer during the back-calculation and, as a result, frequently leads to less than satisfactory, usually over-conservative, design for overlay composites. The principal objective of this research is to develop improved FWD deflection based design strategies for overlay composite pavements. It is proposed that a three-layer linear elastic model be used for back-calculation of the moduli of all three layers: subgrade, PCC and AC. The structural capacity of the existing pavement is estimated using pavement surface deflections measured by FWD, the most commonly used pavement non-destructive testing (NDT) device. In the present study actual FWD deflection data for eleven construction projects are used to back-calculate the moduli of three layers. The three-layer model allows the composite pavement structure to be modeled more accurately. The elastic moduli of the asphalt concrete layer and the underlying Portland cement concrete can both be back-calculated, instead of combining them into one. The results show that the three-layer model produces higher effective thickness than the two-layer model for the same pavement structure, thereby reducing the required overlay thickness. However, there are a number of factors that can strongly influence the final overlay design thickness. The effects of computational error tolerances in back-calculation, temperature at FWD testing and variations in FWD deflection data are found significant and may cause unreliable design results and hence, two strategies to avoid excessively large or small back-calculated moduli are also explored: imposing moduli bounds and relaxing the precision convergence; they have been found very effective in mitigating the effect of large variations in deflection data. The statistical variations observed in the overlay design are also evaluated and two models are explored to improve the overall design procedure from the statistical perspective: Monte Carlo method and Point Estimation method. The effective thicknesses of existing pavement computed from reliability analysis are similar to those obtained from the proposed design method. This demonstrates the validity of the proposed design method and also the applicability of reliability based design in case the statistical parameters are available or can be obtained from engineering judgement.

Committee:

Liangbo Hu (Committee Chair); Eddie Chou (Committee Member); Brian Randolph (Committee Member); Youngwoo Seo (Committee Member); Habib Kaake (Committee Member)

Subjects:

Civil Engineering

Keywords:

composite pavement, overlay design, reliability, temperature correction

Waghulde, Harshal BMapping and CRISPR/Cas9 Gene Editing for Identifying Novel Genomic Factors Influencing Blood Pressure
Doctor of Philosophy (PhD), University of Toledo, 2016, Biomedical Sciences (Cardiovascular and Metabolic Diseases)
Hypertension is a complex polygenic trait and a significant risk factor for cardiovascular and metabolic diseases. Rodent models serve as tools to identify causal genes for complex traits. This dissertation is comprised of two projects. Project 1 utilizes substitution mapping as an approach to locate blood pressure quantitative trait loci (BP QTLs) on rat chromosome 5 (RNO5) and project 2 utilizes Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR Associated proteins 9 (Cas9) genetic engineering as an approach to explore the physiological function of G-protein coupled estrogen receptor (Gper1) in a rat model of hypertension. Previously, using linkage analysis and substitution mapping, two closely-linked interactive blood pressure quantitative trait loci (QTLs), BP QTL1 and BP QTL2, have been defined within 117894038bp-131853815bp region (RGSC 3.4 version) on rat chromosome 5 (RNO5). This was done by using a series of congenic strains consisting of genomic segments of the Dahl salt-sensitive (S) rat substituted with that of the normotensive Lewis (LEW) rat. Through the construction and characterization of a panel of S.LEW bicongenic strains and corresponding S.LEW monocongenic strains, definitive evidence of epistasis (genetic interaction) between BP QTL 1 (7.77Mb) and BP QTL 2 (4.18Mb) has been documented. In order to further map these interacting QTLs, we constructed a new panel of 7 bicongenic strains and monitored their blood pressure by radiotelemetry. The data obtained from these new strains further resolved BP QTL1 from 7.77Mb to 2.93Mb. It was also evident that the QTL2 is not a single QTL, but consists of at least 3 QTLs (2.26Mb, 1.31Mb and 175kb) with contrasting effects on blood pressure. In the second project, we utilized CRISPR/Cas9 genetic engineering approach to study the physiological role of G-protein coupled estrogen receptor (Gper1) in the Dahl-salt sensitive (S) rat. A link between gut microbiota and blood pressure (BP) regulation was previously demonstrated in our laboratory. Gut microbiotal transplantation from Dahl-salt resistant (R) rats into genetically hypertensive Dahl-salt sensitive (S) rats caused an elevation in BP, which was associated with an increase in plasma acetate. Acetate is a short chain fatty acid, which is a known ligand for two of the G-protein coupled receptors, Gpr41 and Olfr78. Deletion of either Gpr41 or Olfr78 is reported to affect BP. Because S and R rats do not have allelic variations of Gpr41 and Olfr78, the observed increased plasma acetate being associated with elevated blood pressure cannot be attributed to these two receptors alone. This led us to hypothesize that yet unknown receptors of acetate exist on the rat genome to regulate BP. To test this hypothesis, we focused on a more recently discovered G-protein coupled estrogen receptor (Gper1) which belongs to the same class of orphan receptors as Gpr41. To completely disrupt Gper1 in S rats, we employed clustered regularly interspaced short palindromic repeats/CRISPR associated protein 9 (CRISPR/Cas9) approach with two gRNAs each targeting one end of the rat Gper1 gene. The resultant Gper1-/- rats had significantly lower BP and increased vasorelaxation to acetylcholine compared to wild type S rats. Further, to examine whether the presence or absence of Gper1 influence vascular response to short chain fatty acids (acetate, propionate and butyrate), wire myograph studies were conducted using small mesenteric arteries (SMAs). While a rapid contraction effect of acetate and butyrate in phenylephrine pre-contracted arteries were similar, the sustained relaxation following rapid contraction was significantly decreased in vessels from Gper1-/- rats. Because gut microbiota is the source of short chain fatty acids, we conducted microbiotal transplantation studies, data from which demonstrated that the observed BP lowering effect of Gper1-/- was abolished. Collectively, the results point to Gper1 as a novel short chain fatty acid receptor.

Committee:

Bina Joe, PhD (Committee Chair); Guillermo Vazquez, PhD (Committee Member); Kathryn Eisenmann, PhD (Committee Member); Jennifer Hill, PhD (Committee Member); Jiang Tian, PhD (Committee Member)

Subjects:

Biomedical Research; Genetics; Health Sciences; Physiology

Keywords:

Blood pressure; quantitative trait loci; rat chromosome 5; epistasis; congenic; G-protein coupled estrogen receptor; CRISPR; gut microbiota; acetate; butyrate

Wu, XiaojunIdentification of two novel in vivo-upregulated Francisella tularensis proteins involved in metal acquisition and virulence
Doctor of Philosophy (PhD), University of Toledo, 2016, Biomedical Sciences (Infection, Immunity, and Transplantation)
Francisella tularensis is the causative agent of the lethal disease tularemia. Despite decades of research, little is understood about why F. tularensis is so virulent. Bacterial outer membrane proteins (OMPs) are involved in various virulence processes, including protein secretion, host cell attachment, and intracellular survival. Many pathogenic bacteria require metals for intracellular survival and OMPs often play important roles in metal binding and uptake. Previous studies identified three F. tularensis OMPs that play roles in iron acquisition. We have identified two new proteins, FTT0267 (named fmvA, for Francisella metal and virulence) and FTT0602c (fmvB), which are homologs of those iron acquisition genes and demonstrated that both are upregulated during mouse infections. Based on sequence homology and in vivo upregulation, we hypothesized that FmvA and FmvB are OMPs involved in metal acquisition and virulence. Despite sequence similarity to previously-characterized iron-acquisition genes, FmvA and FmvB do not appear to be involved iron uptake, as neither fmvA nor fmvB were upregulated in iron-limiting media and neither fmvA nor fmvB mutants exhibited growth defects in iron limitation. However, among other metals examined in this study, magnesium limitation significantly induced fmvB expression, fmvB mutant was found to express significantly higher levels of lipopolysaccharide (LPS) in magnesium-limiting medium, and increased numbers of surface protrusions were observed on fmvB mutant in magnesium-limiting medium, compared to wild-type F. tularensis grown in magnesium-limiting medium. RNA sequencing analysis of fmvB mutant revealed the potential mechanism for increased LPS expression, as LPS synthesis genes kdtA and wbtA were significantly upregulated in fmvB mutant, compared with wild-type F. tularensis. To provide further evidence for the potential role of FmvB in magnesium uptake, we demonstrated that FmvB was outer membrane-localized. Finally, both fmvA and fmvB mutants were found to be significantly attenuated in mice and cytokine analyses revealed that fmvB mutant-infected mice produced lower levels of pro-inflammatory cytokines, including GM-CSF, IL-3, and IL-10, compared with mice infected with wild-type F. tularensis. Taken together, these studies have characterized two previously-unstudied F. tularensis proteins, have shown that both play roles in F. tularensis virulence, and provide new insights into the importance of magnesium for intracellular pathogens.

Committee:

Jason Huntley (Committee Chair); Robert Blumenthal (Committee Member); William Maltese (Committee Member); Kevin Pan (Committee Member); R.Mark Wooten (Committee Member)

Subjects:

Biology; Biomedical Research; Health Sciences; Immunology; Microbiology

Keywords:

Francisella tularensis; outer membrane proteins; virulence; metal acquisition; hypothetical proteins

Tafazolian, HoseinHydroamination and Hydrosilylation Catalyzed by Cationic Palladium- and Nickel(allyl) Complexes Supported by 3-Iminophosphine Ligands
Doctor of Philosophy, University of Toledo, 2016, Chemistry
Chapter 1. A brief introduction to organometallic chemistry and catalysis is presented to explain the basics of the field to the reader. A few examples of catalysis, mainly hydroamination and hydrosilylation, and their mechanisms are presented. The significance of ligands in catalysis is also discussed. Chapter 2. Six new 3-iminophosphine ligands and their cationic (allyl)palladium complexes were synthesized. These catalytically active palladium complexes were utilized in the hydroamination of cyclohexylallene with secondary amines in order to better understand the mechanism of this hydroamination reaction. The kinetics of the reaction were also studied with the help of time-resolved proton NMR spectroscopy, as well as deuterium labeling experiments. Chapter 3. Four new [(3-iminophosphine)nickel(allyl)]OTf complexes were synthesized and characterized by NMR spectroscopy, elemental analysis, and X-ray crystallography. Equimolar reactions of these new complexes with secondary amines provided useful information on the activation of these complexes in the presence of secondary amines. They also catalyzed the hydroamination of terminal allenes with secondary amines to produce allylamines in moderate to high yields, which were then characterized by proton and carbon NMR spectroscopy and high resolution mass spectrometry. Chapter 4. A previously synthesized [(3-iminophosphine)palladium(allyl)]OTf complex was found to be an efficient catalyst for the hydrosilylation of allenes with a wide range of hydrosilanes. Several new allyl- and vinylsilanes were synthesized catalytically and fully characterized. The observed regioselectivity and a double labeled H/D experiment resolved the mechanism of the reaction while also explaining its regioselectivity. Chapter 5. Various cationic palladium and nickel complexes were investigated in the hydrosilylation of imines, ketones, and alkynes. Several new allylamine, silylether and vinylsilane compounds were formed in this study and characterized. Substrate scope and mechanisms of the catalytic reactions are discussed.

Committee:

Joseph Schmidt (Committee Chair); Mark Mason (Committee Member); Steven Sucheck (Committee Member); John-David Smith (Committee Member)

Subjects:

Chemistry

Keywords:

Hydroamination; hydrosilylation; palladium; nickel; 3-iminophosphine ligands

McBeth, Lucien ReiterGlucocorticoid Receptor beta Increases the Migration of Human Urothelial Carcinoma Cells
Master of Science in Biomedical Sciences (MSBS), University of Toledo, 2016, Biomedical Sciences (Cardiovascular and Metabolic Diseases)
Urothelial carcinoma is one of the most prevalent cancers encountered in the country, and recent investigations demonstrate the important role of glucocorticoid signaling in the disease. We have shown that an alternate isoform of the glucocorticoid receptor (GR), GRß, causes migration of human urothelial carcinoma cells. We begin with a literature review of the role of GRß and another nuclear receptor, the androgen receptor, in urothelial carcinoma. Next, we investigate the role of GRß in the migration of human urothelial carcinoma cells in two transitional human uroepithelial carcinoma cells, UMUC-3 and T24. We found that the T24 cells have higher GRß expression compared to the UMUC-3, and that both cell lines had a similar GRa level. Interestingly, the higher GRß expression was correlated with enhanced migration rates, which was reduced with GRß inhibition. In-silco analysis of the 3’ untranslated region (3’UTR) of human GRß revealed a potential micro-RNA (miRNA) binding site for miR33a, miR144, and miR181. Therefore, we cloned the 3’UTR of human GRß and mutated the miRNA binding sites, which showed that miR144 positively regulates GRß expression. In addition, miR144 and GRß expression were increased during migration of uroepithelial carcinoma cells. Therefore, we constructed a peptide nucleic acid (PNA) conjugated to a cell penetrating-peptide (CPP) that we termed Sweet-P to inhibit the miR144 binding site in the 3’UTR of human GRß. Furthermore, Sweet-P decreased GRß expression and, as a result, inhibited migration of uroepithelial carcinoma cells, demonstrating its potential as a therapeutic. We then complete the thesis with a discussion of the potential for Sweet-P in cancer therapy and other GRß-related diseases, which may serve as the first anti-GRß drug.

Committee:

Terry Hinds, Jr (Committee Chair); Edwin Sanchez (Committee Member); Beata Lecka-Czernik (Committee Member); Nitin Puri (Committee Member)

Subjects:

Biomedical Research

Keywords:

Glucocorticoid receptor; GR; GR alpha; GR beta; glucocorticoids; androgens; androgen receptor; AR; cancer; bladder cancer; males; growth; inflammation; microRNA; miRNA; migration; asthma; Sweet-P

Babaie, ElhamSynthesis of Amorphous Alkaline Earth phosphate and its Applications in Orthopedics
Doctor of Philosophy, University of Toledo, 2016, Biomedical Engineering
The focus of this dissertation is synthesis and applications of amorphous alkaline earth phosphate such as magnesium-calcium phosphate and magnesium phosphate. Phosphates of alkaline earths such as calcium phosphates, are of great interest as bone replacement materials because they are biocompatible and resorbable in physiological conditions. As such, they have been studied for a long time. With growing research interest in magnesium alloys, magnesium phosphates have been gaining attention as a bone substitute material with comparable or in some cases, better properties than calcium phosphates. The compositional similarities between calcium phosphates (Ca Ps) and natural bone matrix prompted vigorous research activities in calcium phosphates. By comparison, research on magnesium-calcium phosphates are rare. Among the Ca P, amorphous calcium phosphates (ACP), have found applications as an important class of materials since their presence is important in commercial products such as plasma sprayed coatings on implants to self-setting CaP cements, or the fact that amorphous phase is as an intermediate phase in the synthesis of various crystalline phases of CaP. On the other hand, an understanding of the amorphous phases of magnesium phosphate or magnesium-calcium phosphate, or their transformation into their relevant crystalline phases is rare. For instance, it is shown that doping magnesium (small amount) in calcium phosphate can stabilize amorphous calcium phosphate prior to conversion to hydroxyapatite, However, not much information is available on amorphous magnesium phosphate as reports of synthesis of amorphous magnesium phosphate is scarce in the literature. Accordingly, this dissertation is broadly divided into five sub-sections. The first section reviews the state-of-the-art on processing of porous biomaterials. Porous biomaterials are an important class of materials and important goal of this research is to be able fabricate them in a cost-effective way. The second section discusses the synthesis and applications of amorphous magnesium-calcium phosphate, and amorphous magnesium phosphate as promising biomaterials in comparison to amorphous calcium phosphates or other relevant crystalline phases of calcium phosphates. The focus is on the mechanisms of formation and functional properties such as biocompatibility. In general, several methods have been proposed on the synthesis of amorphous phase, including synthesis from aqueous medium (wet route), using high energy processing or high temperatures (dry route) etc. Among them precipitation (wet route) was chosen in this study, because it is relatively simple and reproducible. Additionally, based on the method of the formation and experimental conditions (solution supersaturation, pH, etc.) different ratios of Ca/P, Mg/P, (Ca+Mg)/P ranging from 1 to 2 or even higher can be produced.The as-synthesized materials were characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). In vitro studies were conducted on mouse osteoblasts, and SEM was used as the imaging methods. In the next of the work, the theme is to investigate the applications of amorphous magnesium-calcium phosphate, and amorphous magnesium phosphate as dense bodies (sintered bioceramic), as cement and also as porous cement scaffold in orthopedic applications. We show that amorphous magnesium phosphate, and amorphous magnesium-calcium phosphate can be produced through ethanol-assisted precipitation method. They are also shown to be biocompatible for relevant applications. The sinterability of amorphous magnesium-calcium phosphate and magnesium phosphate was studied. The results indicate that the amorphous phase of magnesium magnesium-calcium phosphates was able to transform into relevant crystalline phases upon sintering using microwave sintering technique. Next, the development of cement composite consisting of amorphous magnesium phosphate and hydrophilic poly vinyl alcohol (PVA) biopolymer, was carried. Finally, the ability of amorphous magnesium phosphate in fabrication of macroporous composite scaffold through gas-foaming technique was studied. Biodegradable Mg-particles were used as the porogen to produce macroporous structure. This method uses the fast corrosion kinetics of Mg to create macro pores in real time during the setting of the cement.

Committee:

Sarit Bhaduri (Committee Chair); Sarit Bhaduri (Advisor); Arunan Nadarajah (Committee Member); Vijay Goel (Committee Member); Mehdi Pourazady (Committee Member); Champa Jayasuriya (Committee Member)

Subjects:

Biomedical Engineering

Huang, QiuyunStudy on Ultraviolet Light Cured Resin Bond Grind/Lap for Aluminum Oxide Ceramics
Doctor of Philosophy, University of Toledo, 2016, Engineering
After the development of ultraviolet (UV) curing technology, a novel method to manufacture abrasive tools using UV light curing technique was proposed. After decades of research activities, the UV-cured resin bond tools have been studied and proven to have substantial advantages. However, very little researches has been done to study the mechanism of such abrasive tools. In this study, the mechanism of UV-cured resin bond diamond tools was proposed as a Grind/Lap (G/L) process and an experimental method was used to verify the mechanism. Furthermore, the models of surface roughness (RA) and material removal rate (MRR) in the process of ceramics have been intensively investigated. The traditional way to fabricate abrasive tools is by utilizing the thermosetting method. The mixture of abrasives and bond material is sintered at high temperature under extremely high pressure, and it is a time consuming and costly procedure. However, for the UV-curing technique, after being exposed to UV light with a certain intensity, the abrasive-mixed resin can be solidified in a short time. The process is environmentally friendly and has strong productivity advantages but coupled with low energy consumption. The purpose of this research is to understand fundamental issues in UV-curable resin and face grinding of ceramic materials using UV-cured resin bond wheels, including to study the kinematics of face grinding (grinding with lapping kinematics) and the properties of UV-cured abrasive-mixed resin, verify the mechanism proposed for grind/lap process and investigate the effects of several factors on the performance of UV-cured resin bond wheel for aluminum oxide ceramics. The kinematic relation between the workpiece, workpiece holder and the wheel were investigated. The trajectories generated under different speed combinations were simulated. Based on the trace distribution, a combination of the speed of wheel and holder can be suggested and an explanation of interactional effect of the wheel and holder speed was given. The resin 425 was selected by comparing the properties of two resins. The effects of UV-curing time and diamond concentrations on the characteristics of abrasive-mixed resin were studied. The concentration of 12.5 wt. % was selected to investigate the effect of curing time on the performance of resin bond diamond wheel. By studying the abrasive distribution on the surface of abrasive-mixed resin and literature review, the mechanism of the G/L process was proposed as a hybrid of grinding and lapping, with the grinding dominant at the beginning; as machining time increases, the abrasives of small size are released and the G/L process becomes a lapping dominant process (three-body abrasion). In order to prove the proposed mechanism, three experiments performing grinding, lapping, and grind/lap processes were designed. The relation between RA and machining time in three operations agreed with the proposed mechanism, and the outputs of Zygo and SEM of the workpiece surface showed high correspondence with the RA gained respectively. Therefore, the mechanism for the G/L process was validated. Four parameters, including the wheel speed, holder speed, pressure applied, and the UV-curing time, were selected to study the models of RA and MRR in the G/L process for AL2O3 ceramics. The ANOVA results indicated that the four factors and the interaction effect of W*H have significant effects on RA and MRR. The first-order and second-order models with the significant factor terms were established after a logarithmic transformation. The coefficient of determination R^2 and the prediction in error showed that the second-order model explained more variability of the experiment response. The quadratic models of RA and MRR were selected for predicting responses with different factor levels. The errors between the experiment values and values obtained by the model were within a reasonable range, which indicates that these two models are accurate. Therefore, these models can be used to predict the surface roughness and material removal rate for the G/L process.

Committee:

Ioan Marinescu (Advisor)

Subjects:

Engineering

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