Although the synthesis of polymers with highly controlled molecular architectures has gained increased importance due to the rising demand for specialty polymers that possess novel properties, their physical characteristics are direct consequences of the size and constitution of the covalent structures of the polymer. Our program aims to prepare and characterize polymers, whose structures and properties are determined by non-covalent interactions. These novel polymer architectures are comprised of macrocycles threaded by linear macromolecules and are called polyrotaxanes. Polyrotaxanes are considered to be physical analogs of block or graft copolymers or molecular interpenetrating systems. The design and synthesis of the macrocyclic component, "blocking groups" to constrain the macrocycles and the polyrotaxane will be described. / Ph. D.

Polyrotaxanes are novel polymer architectures consisting of theo components. One component is the macrocycel consisting of 24-60 atoms; it is threaded by he second component, i.e., the linear backbone polymer. / Ph. D.

The focus of the following research was to use the self-assembly process to create rotaxanes between several large bisphenylene crown ethers (> 22 atoms) with secondary ammonium salts. Also of great interest was to understand the complexation behavior of the crown ethers with the salts, with emphasis on determining the stoichiometries and association constants of the complexations in solution using NMR spectroscopy. The stoichiometry of the complexes was determined by the mole ratio method and the association constants were calculated graphically. Bis-(m-phenylene)-26-crown-8 did not form a complex in solution with several secondary ammonium salts even though the cavity size is large enough to allow the formation of pseudorotaxanes. However, the larger crown ether, bis-(m-phenylene)-32-crown-10 (BMP32C10), did form a complex. The complex stoichiometry varied between 1:1 (crown:salt) in solution and 1:2 in the solid state as evidenced by NMR and X-ray crystallography, respectively. The solid state complexes were pseudorotaxanes. Also, an interesting "exo" complex was formed in the solid state between BMP32C10 and a secondary diammonium salt. The major binding force for the complexes in the X-ray structures was hydrogen bonding. Weaker secondary stabilization was achieved via aryl-aryl aromatic interactions. The difference between the stoichiometries in the two phases and the observance of an "exo" complex demonstrates that one must be careful in describing the complexes in each phase. Also investigated was the complexation formed between dibenzo-24-crown-8 (DB24C8) and secondary diammonium salts. The association constants for the complexes were found to be relatively higher. Due to the weaker association constants and the different stoichiometries of complexation the meta-susbtituted bisphenylene crown ethers were not recommended for the formation of larger complexes, i.e. polyrotaxanes. However, it is suggested that the DB24C8 moiety be used in components of supramolecular assemblies. The functionalization of poly(propylene imine) dendrimers with two different crown ethers as peripheral moieties was attempted. The 1st, 3rd, and 5th generation poly(propylene imine) dendrimers were functionalized with 1,3-phenylene-16-crown-5 moieties by reacting the surface primary amines with the corresponding succinimide ester of the crown ether. The larger DB24C8 succinimide ester was not as reactive and full functionalization was not achieved. / Ph. D.

The Bass & The Boogeyman is a manuscript of poems that explores issues of sexuality, gender, and identity. The poems also attempt to reach an understanding of what it means to be a member of a largely marginalized social group (homosexuals). In this explorations and a attempts the poems are also engaged in finding the origins of fear. The poems follow one narrator from childhood into adulthood. While the poems do not provide the type of clear narrative and story arc one would expect from a novel, they do offer a sense of trajectory and reward the reader for reading from cover to cover. This manuscript is very aware of itself as a book and strives to exist as such (rather than as a stack of poems who happen to be in the same place at the same time). The manuscript features several connected poem series that work to provide cohesion to the collection. The poems Boys, Men, and Fags are an example of this connection between poems. Each of these three poems can be read as individual pieces, but when taken together they offer a commentary on all three groups that cannot be gained by reading them separately. The manuscript also employers a cast of repeating characters (the boy & the boogeyman among them) to give the collection the sense of narrative trajectory mention above. Lastly, the manuscript combines numerous traditional poetic forms with a wild and unruly use of pop culture and humor. The end result is proof that funny and serious are not always contradictory terms. / Master of Fine Arts

Mountain pine beetles (Dendroctonus ponderosae) are native insects that have decimated millions of hectares of mature pine (Pinaceae) forests in western North America. The purpose of this study is to investigate biophysical and climatic correlates of Mountain Pine Beetle (MPB) insect outbreaks in the Crown of the Continent Ecosystem (CCE) from 1962 to 2014 using Aerial Detection Survey (ADS) and climate data. Specific objectives were: 1) to develop statistical models to determine how selected biophysical correlates (slope, aspect, elevation, and latitude) and 2) to understand how local and global climate variables relate to the extent of the MPB infestations in the CCE, and 3) to contextualize the results of the models with historical climate data. Overall, the major findings of this study are: 1) despite its limitations, the ADS data seems suitable for analysis of beetle damage with respect to climate and topographic factors, on a regional scale, 2) there appears to be a link between local biophysical factors and winter precipitation and TPA within the CCE, and 3) a combination of a negative-phase PDO and La Niña is important in forecasting a decline in MPB spread, during a given year. This study is the first, to our knowledge, to explore spatio-temporal patterns of MPB outbreaks using biophysical factors, and both local and global climate variables, over a fifty-year timespan in the CCE. In the future, additional geospatial analyses may enable a landscape assessment of factors contributing to variability of MPB infestation and damage as this insect continues to spread. / Master of Science

Master of Science

Dibenzo-30-crown-10 (DB30C10) is one of the first-generation macrocyclic hosts discovered by Pedersen. Crown ethers originally attracted attention due to their ability to encapsulate metal cations and render them soluble in organic solvents. These studies helped to launch host-guest chemistry as a discipline within supramolecular chemistry. Crown ethers form complex molecules containing organic cations and neutral organic molecules. Additionally, they form components in supramolecular architectures such as catenanes, rotaxanes, and supramolecular polymers. They have been used as selective hosts in diverse applications such as wastewater treatment, switchable catalysis, therapeutic agents, sensors, molecular machines, and stimuli responsive materials "smart polymers". Despite the vigorous research activity in the field, DB30C10 has received surprisingly little attention. DB30C10 was reported in 1967 and has been commercially available since 1992; however, it has been mostly overlooked as a host in favour of smaller crown ethers such as DB24C8, B15C5, 18C6 and 15C5. Herein we present an improved synthetic route that improves the yield of the cyclization step in the synthesis of DB30C10 from 25% to 88% enabling us to prepare multiple grams of the material without the use of pseudo high-dilution techniques. The same methodology was applied to three other crown ethers with similar improvement in yield. Four new rotaxanes based on the DB30C10-paraquat binding motif were used to investigate the binding conformation of DB30C10 and paraquat. The new rotaxanes were characterized by 1H, 13C and 2D-NOESY NMR, mp, and HRMS. A single crystal X-ray structure of one of the [2]rotaxanes was obtained. To our knowledge, this is the first crystal structure of a rotaxane based on this particular binding motif. This result illustrated that DB30C10 was a suitable host for the construction of supramolecular systems and polymers. Our eventual goal is to use DB30C10 in the construction of supramolecular polymers with novel topologies. Therefore, the relative threading efficiency of DB30C10 in solution had to be determined. A series of segmented polyurethane poly(pseudorotaxanes) with paraquats in the backbone were synthesized with different crown ether or cyptand hosts. The threading efficiency was determined by 1H NMR. / Ph. D.

Crown gall of grapevine (Vitis spp.) is a serious and economically important disease caused by the bacterial pathogen Rhizobium vitis, which transforms healthy plant cell genomes leading to hypertrophic and hyperplastic growth of affected plant cells. Recent studies have documented a strong inhibitory effect against Japanese tumorigenic R. vitis isolates by a newly identified non-tumorigenic strain of R. vitis, ARK-1. We conducted co-inoculation assays in tomato (Solanum lycopersicum) and wine grape cultivars (Vitis vinifera) with four tumorigenic isolates of R. vitis from Virginia. These tumorigenic isolates were co-inoculated with ARK-1 in various ratios and resulting gall incidence and gall size were measured. Analysis was conducted with the generalized linear mixed model (GLIMMIX) in SAS (ver. 9.4). ARK-1 significantly reduced both the mean probability of gall formation and the mean gall size (P < 0.05). ARK-1 efficacy against combinations of two or four tumorigenic isolates and up to twice as many cells of tumorigenic isolates was also significant. However, there was an indication of a loss of efficacy when ARK-1 was challenged with four isolates at four times the cell number of ARK-1. Also, the efficacy of ARK-1 was influenced by both the specific isolate and host plant used in the study. Our results suggest that ARK-1 has promising potential as an effective biological control agent for grapevine crown gall in the United States. / MSLFS / Crown gall of grapevine (Vitis species) is a serious and economically important disease to the grape production industry caused by the bacterium Rhizobium vitis. This pathogen alters the genetic material of plant cells leading to cancer-like growth of affected plant cells (tumors); which may lead to the death of a grapevine. Recently, a non-tumor inducing strain of R. vitis (ARK-1) was documented to inhibit gall induction by tumor-inducing R. vitis strains in Japan. To see if ARK-1 would be a good candidate for biological control of the tumor-causing strains of R. vitis in the US, we tested it against four tumor-inducing strains in both tomato (Solanum lycopersicum) and grapevine (Vitis vinifera). The tumor-inducing strains were mixed with ARK-1, injected into plant stems in various ratios, and resulting gall incidence and gall size were measured 42 to 90 days later. ARK-1 significantly reduced both the probability of gall formation and the gall size in both tomatoes and grapevines. ARK-1 was an effective agent against mixtures of one, two, or four tumor-inducing strains and provided control even when outnumbered two to one by cells of tumor-inducing strains. The efficacy of ARK-1 was influenced by the specific strain, relative cell number to tumor-inducing strains, and host plant used in the study. Our results suggest that ARK-1 has promising potential as an effective biological control agent for grapevine crown gall in the United States.

Grapevine crown gall causes significant economic damage in vineyards and nurseries worldwide. Infected vines are not curable due to irreversible genomic transformation by the tumorigenic bacterium Rhizobium vitis. Crown gall results in a gradual decline in yield and vine vigor, then the complete collapse of the vine. R. vitis ARK-1, an antagonistic and non-tumorigenic strain, has been shown to inhibit gall formation when equal cell concentrations of antagonist and tumorigenic strains are co-inoculated in planta. In this study, we tested the efficacy of ARK-1 against higher cell numbers of tumorigenic isolates and evaluated timing and methods of ARK-1 application in in-planta assays in grapevine (Vitis vinifera 'Chardonnay', 'Cabernet Sauvignon', 'Merlot') and tomato (Solanum lycopersicum 'Beefsteak'). ARK-1 significantly (P ≤ 0.01) reduced gall incidence and gall diameter against four times higher tumorigenic bacterial cell numbers. Inoculation of ARK-1 up to 48 hours before or within 6 hours after inoculation with tumorigenic isolates significantly (P ≤ 0.01) reduced gall incidence and gall diameter. Root dipping of grapevine for 24 hours and tomato for 1 hour in the formulated ARK-1 suspension (Kumiai Chemical Industry Co. Ltd., Japan) prior to transplanting in tumorigenic bacteria-infested soil completely inhibited gall formation in the roots. These results are promising and support the development of ARK-1 as a biological control agent to manage grapevine crown gall. / Master of Science in Life Sciences / Grapevine crown gall is an economically significant disease in vineyards and nurseries worldwide. The pathogen of grapevine crown gall alters plant genome and causes tumor-like gall formation. Infected vines lose yield and vigor and eventually get killed. In this study, we tested the efficacy of a biological control agent called ARK-1. We challenged ARK-1 against higher cell numbers of pathogenic bacteria, evaluated timings, and practical methods of ARK-1 application. We conducted our greenhouse studies in grapevine (Vitis vinifera) cultivars 'Chardonnay', 'Cabernet Sauvignon', 'Merlot' and tomato (Solanum lycopersicum) cultivar 'Beefsteak'. In efficacy test, ARK-1 was effective and reduced 68% gall incidence against a four times higher pathogenic bacteria mixture. In timing assay, the application of ARK-1 up to 48 hours before inoculation of pathogenic bacteria reduced gall formation by more than 95%. Also, ARK-1 was effective when it was applied within 6 hours after inoculation of pathogenic bacteria. Root soaking of grapevine and tomato in the formulated ARK-1 suspension (KUF-1511, Kumiai Chemical Industry Co. Ltd., Japan), prior to transplanting in pathogenic bacteria-infested soil, completely inhibited gall formation in the roots. The promising result of this study is a step forward towards use of ARK-1 as a biological control agent to manage grapevine crown gall disease.

Rotaxane chemistry provides a new direction of research in polymer architectures. Unlike conventional polymers, polyrotaxanes are molecular composites comprised of macrocycles threaded by linear polymer backbones with no covalent bonds between the two components. This novel class of materials displays unusual chemical and physical properties due to their unique architectures. The studies include crown ether and blocking group syntheses, synthetic methodologies leading to rotaxanes and polyrotaxanes and structure-property relationships of polyrotaxanes. Crown ethers (30-crown-10, 36-crown-12, 42-crown-14, 48-crown-16 and 60-crown-20) were systematically synthesized from low molecular weight glycols with 30 - 60% yields. Bis(p-phenylene)-32-crown-4 and bis(p-phenylene)-34-crown-10 (BPP34C10) were also synthesized in 8 - 13% yields; the latter was synthesized with four different synthetic routes. All crown ethers were prepared in large quantities. A series of monofunctionalized triaryl derivatives were also synthesized as rotaxane blocking groups. A series of polyrotaxanes comprised of a polyurethane backbone and crown ethers with ring size ranging from 36 - 60 membered were synthesized via the statistical threading method. The polyrotaxane formation was proven by multiple reprecipitations, ¹H-NMR and GPC analyses. The threading efficiency (rings per repeat unit) increases from 0.16 to 0.87 with an increase in ring size of crown ethers from 36 to 60 membered at 1.5 molar ratio of crown ether to linear glycol. Host-guest complexation of paraquat dication and BPP34C10 has been studied. A series of difunctionalized paraquat dication derivatives was synthesized and used to prepare host-guest complexes (pseudorotaxanes) with BPP34C10. X-Ray crystal structures of the complexes were determined. Furthermore, a class of viologen-containing polyurethane elastomeric polyrotaxanes was synthesized via this host guest complexation. The threading efficiencies from this method were quantitative. Through rotaxane formation, polymer solubilities increase and glass transition temperatures decrease. Evidenced by DSC and WAXS analyses, the crown ether forms crystalline domains without dethreading from the amorphous polyurethane backbone. This process is kinetically "retarded". It is time and temperature dependent and reversible. It can only be observed for polyrotaxanes with large rings and high ring contents, which provide high mobilities of rings along the backbone and also wide T_m - T_g windows. The study of recrystallization kinetics has also shown that 60-crown-20 recrystallizes much slower in a polyrotaxane than in its physical blend with the model polymer. / Ph. D.