Digital Commons Network^™

Irrelevance, Polymorphism, And Erasure In Type Theory, Richard Nathan Mishra-Linger

Dissertations and Theses

Dependent type theory is a proven technology for verified functional programming in which programs and their correctness proofs may be developed using the same rules in a single formal system. In practice, large portions of programs developed in this way have no computational relevance to the ultimate result of the program and should therefore be removed prior to program execution. In previous work on identifying and removing irrelevant portions of programs, computational irrelevance is usually treated as an intrinsic property of program expressions. We find that such an approach forces programmers to maintain two copies of commonly used datatypes: a …

Synthesis, Characterization And Reactivity Of Some Selected Organosulfur Oxo-Acids, Adenike Otoikhian

Dissertations and Theses

The two major metabolites after S-Oxygenation of dimethylthiourea (N, N'-dimethylaminoiminomethanesulfinic acid (DMAIMSA) and N, N'-dimethylamino iminomethanesulfonic acid (DMAIMSOA)) were synthesized. Structural analysis by X-ray crystallography shows that DMAIMSA and DMAIMSOA exist as zwitterionic species in their solid form, with a positive charge delocalized around an sp²-hybridized carbon center flanked by two nitrogen atoms.

Kinetics and mechanistic studies on the oxidation of DMAIMSA and DMAIMSOA by acidified iodate/iodine and bromate/bromine were studied. The results reveal that DMAIMSA, unlike DMAIMSOA, is highly reactive. DMAIMSOA is very inert and unreactive in low pH environments. The difference in reactivity is attributed to …

Window Queries Over Data Streams, Jin Li

Dissertations and Theses

Evaluating queries over data streams has become an appealing way to support various stream-processing applications. Window queries are commonly used in many stream applications. In a window query, certain query operators, especially blocking operators and stateful operators, appear in their windowed versions. Previous research work in evaluating window queries typically requires ordered streams and this order requirement limits the implementations of window operators and also carries performance penalties. This thesis presents efficient and flexible algorithms for evaluating window queries. We first present a new data model for streams, progressing streams, that separates stream progress from physical-arrival order. Then, we …

The Original Build Up Of Genetic Information By Rna Recombination, Eric John Hayden

Dissertations and Theses

This research demonstrates chemical reactions of RNA molecules that allow them to increase in length, from non-catalytic oligomers to complex RNA enzymes. The purpose of this research was to explain the origin of large RNA polymers required for life to begin in the proposed "RNA World". To do this, the Azoarcus group I ribozyme was engineered to catalyze phosphodiester exchange reactions that result in the recombination of short oligomer substrates marked by ^5'CAU^3' recognition tags.

To demonstrate the ability to produce catalytic RNA sequences through recombination, substrate oligomers were synthesized that could produce ribozymes if large portions of …

Students' Reasoning About The Concept Of Limit In The Context Of Reinventing The Formal Definition, Craig Alan Swinyard

Dissertations and Theses

Many researchers (Artigue, 2000; Bezuidenhout, 2001; Cornu, 1991; Dorier, 1995) have noted the vital role limit plays as a foundational concept in analysis. The vast majority of topics encountered in calculus and undergraduate analysis are built upon understanding the concept of limit and being able to work flexibly with its formal definition (Bezuidenhout, 2001). The purpose of this study was to: (1) Develop insight into students' reasoning about limit in relation to their engagement in instruction designed to support their reinventing the formal definition of limit, and; (2) Inform the design of principled instruction that might support students' attempts to …

Nanostructered Aminophenylporphyrin Films For Use In Bulk Heterojunction And Inverse Dye-Sensitized Tio₂ Solar Cells, Michael George Walter

Dissertations and Theses

Conductive nanostructured films of poly-tetrakis-5,10,15,20-(4-aminophenyl)porphyrin (TAPP) can be grown electrochemically or through interfacial oxidative polymerization. The poly-TAPP nanomorphology is sensitive to the electrochemical solvent, potentiometric method, and the aminophenyl porphyrin monomer utilized. To elucidate the molecular structure of poly-TAPP and to correlate structures with proposed polymerization and conductivity mechanisms, reflectance FT-IR and spectroelectrochemistry were used to detect the presence and electroactivity of dihydrophenazine and phenazine polymer linkages formed during the polymerization.

Poly-TAPP nanofiber films were evaluated for use in a bulk heterojunction solar cell (with PCBM) and in an inverse dye-sensitized TiO2 solar cell using the poly-TAPP nanoporous scaffold to …

Design And Synthesis Of Antimalarial Drugs Based On A Chloroquine Scaffold, Steven James Burgess

Dissertations and Theses

There are between 350 and 500 million clinical cases of malaria each year, and over 1 million deaths, with pregnant women and children under the age of 5 being most at risk. Chloroquine (CQ) became the preferred drug to treat malaria in the late 1940s, but is now rendered mostly ineffective in many parts of the world, due to widespread CQ resistance by the malaria parasite. All other malaria treatments suffer from some drawbacks, which include development of resistance, side effects including toxicity, risk for pregnant women and young children, and high cost. Some existing, non-antimalarial, drugs have been found …

What's Regulation Got To Do With It? : Examining The Impact Of Regulatory Intensity On Facility Environmental Management And Performance, Cody Jones

Dissertations and Theses

Understanding the influence of regulation on environmental management is important—studies typically find regulation to be a significant influence on environmental activity. However, studies typically assess regulation together with a suite of other influences such as investors and customers, which are often also found to be significant influences on environmental management. This research, on the other hand, suggests that regulatory constraints form a framework within which organizations operate, and therefore are associated with organizations' views of other motivating factors, as well as environmental management and performance. Additionally, this study assesses the influence of management attitudes toward environmental protection and attitudes toward …

A Novel Approach To The Synthesis Of Silicon Nanowires, Joo Chick Chan

Dissertations and Theses

Contemporary VLS-SiNW synthetic methods employ CVD and laser ablation methods that produce single crystalline SiNW; which can be doped by co-flowing appropriate dopants, such as diborane (p-type) and phosphine (n-type). Not only are these gases toxic (non-green), but also the synthetic methods used are costly requiring elaborate instrumental assembly. This thesis presents a low-cost and "green" method in synthesizing and doping of SiNW in a glass tube. It was found that by selecting the appropriate metal catalyst, precursor reactants, and the reaction conditions both SiNW and carbon nanotube (CNT) can be synthesized on metallic (aluminum and copper), semiconducting (silicon) and …

Peroxynitrite Chemistry: Formation, Decomposition And Possible Deactivation Mechanisms By Thiols, Olufunke Modupe Olagunju

Dissertations and Theses

Kinetics of formation and decomposition of peroxynitrite was studied in acidic and buffer solutions. Peroxynitrous acid was formed in acidic media by the reaction of H₂O₂ with HNO^₂ and NO +. Bimolecular rate constant for reaction of H²O² with HNO^₂ at 25°C was determined to be 3.7 × 10 3 M-¹ s-¹. Peroxynitrous acid formed is highly unstable with half life of approximately 1 second. Decomposition of peroxynitrite is highly pH-dependent. In acidic media, peroxynitrous acid decomposes to nitrate while at neutral to slightly basic media, products of decomposition …

Theoretical Investigations And Microarray Applications Of Dna Multiplex Hybridization Reactions, Michael Todd Horne

Dissertations and Theses

General equilibrium and kinetic models with numerical solutions describing DNA multiplex hybridization reactions are developed and presented. Theoretical investigations on example multiplex systems were carried out in order to test the sensitivity of the model system to a variety of experimental and model parameters. A spotted microarray platform was calibrated to yield quantitative results, and the theoretical model motivated the design of an effective kinetic assay to discriminate SNPs in a multiplex fashion. Effects of duplex length, %G+C and relative position of the SNP on duplex hybridization and SNP resolution were determined. The theoretical model of multiplex hybridization accurately predicted …

Development And Investigation Of Unique Organic Materials To Detect Disease Biomarkers, George Kiplimo Samoei

Dissertations and Theses

Chemomechanical polymer gels with the capability of recognizing specific biological molecules are promising materials for many biomedical applications. Glucose-selective hydrogels have potential utility in the continuous monitoring of glucose and glucose-triggered insulin delivery for the management of diabetes. Herein, the development and study of the first material which detects glucose via significant volume changes in the challenging matrix human blood plasma is described. The material was created via the modification of PMMA with supramolecular binding sites. The polymer exhibits excellent selectivity and reversibility including continuous expansion-contraction cycles.

Semantic Components: A Model For Enhancing Retrieval Of Domain- Specific Information, Susan Loucette Price

Dissertations and Theses

Despite the success of general Internet search engines, information retrieval remains an incompletely solved problem. Our research focuses on supporting domain experts when they search domain-specific libraries to satisfy targeted information needs. The semantic components model introduces a schema specific to a particular document collection. A semantic component schema consists of a two-level hierarchy, document classes and semantic components. A document class represents a document grouping, such as topic type or document purpose. A semantic component is a characteristic type of information that occurs in a particular document class and represents an important aspect of the document’s main topic. …

Quantifying Twentieth Century Glacier Change In The Sierra Nevada, California, Hassan J. Basagic

Dissertations and Theses

Numerous small alpine glaciers occupy the high elevation regions of the central and southern Siena Nevada, California. These glaciers change size in response to variations in climate and are therefore important indicators of climate change. An inventory based on USGS topographic maps (l :24,000) revealed 1719 glaciers and perennial snow and ice features for a total area of 39.l5 ±7.52 km². The number of 'true' glaciers, versus non-moving ice, is estimated to be 118, covering 15.87 ± 1.69 Km². All glaciers were located on north to northeast aspects, at elevations >3000 m. Historical photographs, geologic evidence, …