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  Partner: UNT Libraries
 Degree Level: Doctoral
 Collection: UNT Theses and Dissertations
Design, Synthesis, and Characterization of Aqueous Polymeric Hybrid Composites and Nanomaterials of Platinum(ii) and Gold(i) Phosphorescent Complexes for Sensing and Biomedical Applications

Design, Synthesis, and Characterization of Aqueous Polymeric Hybrid Composites and Nanomaterials of Platinum(ii) and Gold(i) Phosphorescent Complexes for Sensing and Biomedical Applications

Date: December 2015
Creator: Upadhyay, Prabhat K.
Description: The two major topics studied in this dissertation are the gold(I) pyrazolate trimer {[Au(3-R,5-R’)Pz]3} complexes in aqueous chitosan polymer and phosphorescent polymeric nanoparticles based on platinum(II) based complex. The first topic is the synthesis, characterization and optical sensing application of gold(I) pyrazolate trimer complexes within aqueous chitosan polymer. A gold(I) pyrazolate trimer complex, {[Au(3-CH3,5-COOH)Pz]3}, shows high sensitivity and selectivity for silver ions in aqueous media, is discussed for optical sensing and solution-processed organic light emitting diodes (OLEDs) applications. Gold(I) pyrazolate trimer complexes are bright red emissive in polymeric solution and their emission color changes with respect to heavy metal ions, pH and dissolved carbon dioxide. These photophysical properties are very useful for designing the optical sensors. The phosphorescent polymeric nanoparticles are prepared with Pt-POP complex and polyacrylonitrile polymer. These particles show excellent photophysical properties and stable up to >3 years at room temperature. Such nanomaterials have potential applications in biomedical and polymeric OLEDs. The phosphorescent hybrid composites are also prepared with Pt-POP and biocompatible polymers, such as chitosan, poly-l-lysine, BSA, pnipam, and pdadmac. Photoluminescent enhancement of Pt-POP with such polymers is also involved in this study. These hybrid composites are promising materials for biomedical applications such as protein labeling and ...
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Design, Synthesis and Study of Supramolecular Donor – Acceptor Systems Mimicking Natural Photosynthesis Processes

Design, Synthesis and Study of Supramolecular Donor – Acceptor Systems Mimicking Natural Photosynthesis Processes

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Date: December 2015
Creator: KC, Chandra Bikram
Description: This dissertation investigates the chemical ingenuity into the development of various photoactive supramolecular donor – acceptor systems to produce clean and carbon free energy for the next generation. The process is inspired by the principles learned from nature’s approach where the solar energy is converted into the chemical energy through the natural photosynthesis process. Owing to the importance and complexity of natural photosynthesis process, we have designed ideal donor-acceptor systems to investigate their light energy harvesting properties. This process involves two major steps: the first step is the absorption of light energy by antenna or donor systems to promote them to an excited electronic state. The second step involves, the transfer of excitation energy to the reaction center, which triggers an electron transfer process within the system. Based on this principle, the research is focused into the development of artificial photosynthesis systems to investigate dynamics of photo induced energy and electron transfer events. The derivatives of Porphyrins, Phthalocyanines, BODIPY, and SubPhthalocyanines etc have been widely used as the primary building blocks for designing photoactive and electroactive ensembles in this area because of their excellent and unique photophysical and photochemical properties. Meanwhile, the fullerene, mainly its readily available version C60 is ...
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Detection of Ulcerative Colitis Severity and Enhancement of Informative Frame Filtering Using Texture Analysis in Colonoscopy Videos

Detection of Ulcerative Colitis Severity and Enhancement of Informative Frame Filtering Using Texture Analysis in Colonoscopy Videos

Date: December 2015
Creator: Dahal, Ashok
Description: There are several types of disorders that affect our colon’s ability to function properly such as colorectal cancer, ulcerative colitis, diverticulitis, irritable bowel syndrome and colonic polyps. Automatic detection of these diseases would inform the endoscopist of possible sub-optimal inspection during the colonoscopy procedure as well as save time during post-procedure evaluation. But existing systems only detects few of those disorders like colonic polyps. In this dissertation, we address the automatic detection of another important disorder called ulcerative colitis. We propose a novel texture feature extraction technique to detect the severity of ulcerative colitis in block, image, and video levels. We also enhance the current informative frame filtering methods by detecting water and bubble frames using our proposed technique. Our feature extraction algorithm based on accumulation of pixel value difference provides better accuracy at faster speed than the existing methods making it highly suitable for real-time systems. We also propose a hybrid approach in which our feature method is combined with existing feature method(s) to provide even better accuracy. We extend the block and image level detection method to video level severity score calculation and shot segmentation. Also, the proposed novel feature extraction method can detect water and bubble frames ...
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Determining the Authenticity of the Concerto for Two Horns, Woo 19, Attributed to Ferdinand Ries

Determining the Authenticity of the Concerto for Two Horns, Woo 19, Attributed to Ferdinand Ries

Date: December 2015
Creator: Laursen, Amy D.
Description: Ferdinand Ries is credited as the composer of the Concerto for Two Horns, WoO. 19 preserved in the Berlin State Library. Dated 1811, ostensibly Ries wrote it in the same year as his Horn Sonata, Op. 34, yet the writing for the horns in the Concerto is significantly more demanding. Furthermore, Ries added to the mystery by not claiming the Concerto in his personal catalog of works or mentioning it in any surviving correspondence. The purpose of this dissertation is to study the authorship of the Concerto for Two Horns and offer possible explanations for the variance in horn writing. Biographical information of Ries is given followed by a stylistic analysis of Ries’s known works. A stylistic analysis of the Concerto for Two Horns, WoO. 19 is offered, including a handwriting comparison between the Concerto for Two Horns and Ries’s Horn Sonata. Finally, possible explanations are proposed that rationalize the variance in horn writing between the Concerto for Two Horns, WoO. 19 and Ries’s other compositions that include the horn.
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Does Instructional Delivery Method in an Elective Business Class Impact Student Achievement with Respect to Gender, Race and Socio-economic Status in a Selected Texas Public School District?

Does Instructional Delivery Method in an Elective Business Class Impact Student Achievement with Respect to Gender, Race and Socio-economic Status in a Selected Texas Public School District?

Date: December 2015
Creator: Moore, Eldridge D.
Description: The problem that guided this study was a socio-constructivist view of education via online learning. Based in the extant literature, a deficiency existed that directly correlated online learning closing the academic achievement gap between student populations. In other words, schools invested in technology; however, few empirical data sets existed that established a connection between technology integration and the academic achievement of different student groups. The purpose of this pooled regression analysis study was to determine whether the method of class instruction effected academic achievement gaps between three subpopulations based on gender, race, and SES. Specifically, this study examined whether gender, race, and SES could predict semester grades within and across traditional, blended, and online course instructional methods. The dependent variable for this study was student success in the form of an end-of-unit test grade designed to evaluate student understanding of the curriculum. The independent variables included student gender, ethnicity, and SES. Quantitative data were collected through an analysis of Public Education Information Management System (PEIMS) data and student end-of-unit exam grades. The research suggests one combined interaction, [gender x race] in the traditional learning environment, is statistically significant while several independent interactions are significant. Those independent interactions are TAKS scores, ...
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An Educational Intervention to Promote Self-management and Professional Socialization in Graduate Nurse Anesthesia Students

An Educational Intervention to Promote Self-management and Professional Socialization in Graduate Nurse Anesthesia Students

Date: December 2015
Creator: Maloy, Debra A.
Description: Traditionally, nurse anesthesia educators have utilized prior academic achievement to predict student success. However, research has indicated that prior academic achievement offers an inadequate assessment of student success in graduate healthcare programs with extensive clinical residencies. The educational literature has identified many non-cognitive factors, such as self-efficacy and locus of control, that may provide a more holistic prediction model of student success. An experimental study with pretest-posttest design and stratified random assignment was conducted to evaluate the effectiveness of an educational intervention to promote self-management, professional socialization, and academic achievement among first semester graduate nurse anesthesia students. Participants (N = 66) were demographically similar to the national graduate nurse anesthesia student body, though Hispanics and younger students were a little over-represented in the sample (56% female, 75.8% White, 15.2% Hispanic, 6% Other, 59% ≤ 30-years-old, 67% ≤ 3 years of ICU). The results showed that most graduate anesthesia students had strong self-management and professional socialization characteristics on admission. The results did not support the effectiveness of this educational intervention. Thus, ceiling effect may have accounted in part for statistically non-significant results regarding self-efficacy (p = .190, ω2 = .03), locus of control (p = .137, ω2 = .04), professional socialization ...
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Effects of Child Development Associate Credential System 20 on Candidate Success Rates

Effects of Child Development Associate Credential System 20 on Candidate Success Rates

Date: December 2015
Creator: Davis, Travis J.
Description: The purpose of this research was to identify the impact of process changes that have been made to the Child Development Associate (CDA) credential, which is a beginning early childhood teacher credential that focuses on competency based standards widely seen as necessary for early childhood teachers to possess. The process in which early childhood teachers receive their credential changed in 2013 with the implementation of CDA credential 2.0. Changes included taking a computerized exam and the implementation of a professional development specialist conducting an on-site classroom observation. In order to determine the impact that CDA 2.0 had on teacher credentialing success rates, a mixed-method sequential design was employed. First, existing data sets of success rates from a national scholarship program were reviewed. Following, interviews with CDA credential seekers were conducted. Findings revealed that while candidate success rates increased for those receiving CDA credentials under the 2.0 system, the actual number of candidates receiving scholarships to pursue the CDA credential through the national scholarship program decreased. Qualitative analysis of the semi-structured interviews indicated that three areas that impacted CDA 2.0 candidate success rates were the professional education programs and instructors, the CDA Exam, and Professional Development Specialists. This is the first ...
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Environmental Modulation of the Onset of Air-breathing of the Siamese Fighting Fish and the Blue Gourami

Environmental Modulation of the Onset of Air-breathing of the Siamese Fighting Fish and the Blue Gourami

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Date: December 2015
Creator: Mendez Sanchez, Jose Fernando
Description: This study determined the effect of hypoxia on air-breathing onset and physiological and morphological characters in larvae of the air breathing fishes Trichopodus trichopterus and Betta splendens. Larvae were exposed intermittently (12/12 h daily) to 20, 17, and 14 kPa of PO2 from 1 to 40 days post-fertilization. Survival, onset of air breathing, wet body mass, O2, Pcrit were measured every 5 dpf. Hypoxia advanced by 4 days, and delayed by 9 days, the onset of air breathing in Betta and Trichopodus, respectively. Hypoxia increased larval body length, wet mass, and labyrinth organ respiratory surface of Betta, but did not affect these factors in Trichopodus. Hypoxic exposure increased O2 by 50-100% at each day throughout larval development in Betta, but had no effect on larval Trichopodus. Hypoxia decreased Pcrit in Betta by 37%, but increased Pcrit in Trichopodus by 70%. Larval Betta reared in hypoxia showed a modified heart rate:opercular rate ratio (3:1 to 2:1), but these changes did not occur in Trichopodus. Compared to Betta, the blood of Trichopodus had a higher P50 and much smaller Bohr and Root effects. These interspecific differences are likely due to ecophysiological differences: Betta is a non- obligatory air-breather after 36 dpf with ...
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Expertise Revisited: Reflecting on the Intersection of Science and Democracy in the Case of Fracking

Expertise Revisited: Reflecting on the Intersection of Science and Democracy in the Case of Fracking

Date: December 2015
Creator: Ahmadi, Mahdi
Description: This dissertation aims to explain the conditions under which expertise can undermine democratic decision making. I argue that the root of the conflict between expertise and democracy lies in what I call insufficiently “representative” expertise – that is forms of scientific research that are not relevant to the policy questions at hand and that fail to make visible their hidden values dimensions. I claim that the scholarly literature on the problem of expertise fails to recognize and address the issue correctly, because it does not open the black box of scientific methodologies. I maintain that only by making sense of the methodological choices of experts in the context of policy making can we determine the relevance of research and reveal the hidden socio-political values and consequences. Using the case of natural gas fracking, I demonstrate how expert contributions – even though epistemically sound – can muddle democratic policy processes. I present four case studies from controversies about fracking to show how to contextualize scientific methodologies in the pertinent political process. I argue that the common problem across all case studies is the failure of expertise to sufficiently represent stakeholders’ problems and concerns. In this context, “representation” has three criteria: (1) ...
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Exploring Student Learning on a Short-term, Faculty-led Study Abroad Course Through a Student Development Lens

Exploring Student Learning on a Short-term, Faculty-led Study Abroad Course Through a Student Development Lens

Date: December 2015
Creator: Garcia, Hope F.
Description: Embarking on a study abroad experience is thought to be a transformational experience for students, and previous researchers have tended to find that the potential benefits of study abroad experiences, including greater conceptual and behavioral intercultural competence, are greater with longer periods abroad. The purpose of this study was to create an intentional learning experience for students who embarked on a short-term study abroad in rural areas of China and to apply faculty intervention of a student development approach to student learning to create a high-impact learning environment for students centered on a service-learning project. This qualitative study gathered primary data from students and instructors during the course through a collection of observation and field notes, student journals, pre- and post-construct tests, and final presentation. Follow-up interviews were conducted 10 months after course completion. Six students participated in this course and study who were from a variety of disciplines and classifications. Five students were female; one was male. Four students were undergraduates; two were graduate students. Student ethnicities included three Caucasians and African American, along with two international students from Mexico and Iran. Key outcomes of this study were that when short-term study abroad faculty members applied creative interventions, students ...
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