This dissertation investigates the effects of price, brand name, and level of advertising on consumers’ perceptions of service quality, service value, and their willingness to stay at a lodging facility. Hypotheses are derived from a conceptual model to posit the relationship that the three extrinsic cues of price, brand name, and level of advertising have with the constructs of perceived service quality, perceived service value, and willingness to stay (purchase intention). Additionally, the interaction effects of the extrinsic cues on the three constructs are evaluated. Moreover, the relationships among the constructs of perceived service quality, perceived service value, and willingness to stay are examined. Overall, the analysis gave strong support for the hypothesized effects of price. There was a lack of support for the hypothesized effects of brand name and level of advertising on consumers’ service evaluations. Results revealed that perceived service value is a more comprehensive measure of consumers’ overall evaluation of a service than perceived service quality. Theoretically, this research partially tests a model that goes beyond the price perceived good quality paradigm. Managerially, this study helps in determining the price, brand name, and level of advertising appropriate to obtain better service evaluations from consumers. / Ph. D.

In Dictyostelium, glycogen metabolism plays a major role in development. Undifferentiated cells contain stores of glycogen that are broken down and converted to structural components in differentiated cells. The enzyme that synthesizes this developmentally important pool of glycogen is glycogen synthase. I have cloned the entire coding and 1.3 kb of upstream noncoding region, of glycogen synthase, using PCR amplification and genomic library screening. In order to clone the 3’ portion of the gene it was necessary to develop a new technique, enrichment-PCR, that relies on the base composition of the Dictyostelium genome. Due to the high A+T content of the Dictyostelium genome, a polyT primer and a gene specific primer were used to amplify an unknown DNA fragment, flanking a known sequence. Analysis of the complete coding region showed that glycogen synthase possesses three introns that contain the consensus splice sites for Dictyostelium. The luciferase reporter gene was used to study the transcriptional regulation of glycogen synthase. I defined the cis-acting elements that are required for proper transcriptional regulation of glycogen synthase by using promoter/luciferase fusions of varying sizes. Using the luciferase reporter system a putative promoter element was identified. Additional luciferase constructs were made to identify the specific nucleotide involved in transcription of the glycogen synthase gene. Small defined deletions are often necessary for reporter gene analysis. We have developed a deletion cassette that can expand the functionality of any commonly-used vector. The deletion cassette confers the ability to make small specific sequential deletions of the DNA flanking the cassette. We have shown that this altered vector (pDNBL) now has the ability to create 2, 4, 5 or 9 bp deletions. A number of experimental approaches were taken to study the regulation of glycogen synthase. Homologous recombination was used to try to generate a glycogen synthase (-) cell line. In addition, I have constructed a green fluorescent protein (GFP) vector (pNV) based on the pVTL2 vector. This reporter gene is useful for monitoring the expression of a particular gene in vivo. / Ph. D.

Most of the surface-mined land in the southern Appalachian coal fields of Virginia, southern West Virginia, and eastern Kentucky is forested before mining. For a variety of reasons, most surface-mined land will ultimately return to forest, either by design or through natural succession. The usefulness of forests on reclaimed surface-mined land for providing timber management opportunities depends on whether or not the land is reclaimed in a manner which creates a productive forest soil. Surveys of tree plantings on land that was mined prior to enactment of the 1977 Surface Mining Control and Reclamation Act (SMCRA) have shown that trees will grow well where 1) minesoils are non-toxic, 2) minesoils are deep, loose, and uncompacted, and 3) tree seedling establishment is not hindered by competition from an herbaceous ground cover. Several experiments were conducted to develop practical recommendations for post-SMCRA reclamation of surface-mined forest land to create these desirable minesoil conditions. An experiment designed to evaluate the effect of two contrasting spoil types revealed that the type of overburden material used as a topsoil substitute can have long-term effects on tree growth. After five years, average tree volume in a sandstone spoil was five times greater than tree volume in a siltstone spoil. In the southern Appalachians, oxidized (brown) sandstone is a good overburden to use as a topsoil substitute for forest land reclamation. A second experiment was conducted to evaluate the effect of surface grading practices on erosion, herbaceous ground cover, and tree survival and growth. After five years, study results revealed that traditional grading practices caused excessive soil compaction that resulted in higher erosion and poorer tree growth than treatments that left the soil in a loose condition. A third experiment was conducted to compare the effect of two herbaceous ground cover prescriptions (a tree-compatible ground cover versus the coal operator’s standard revegetation mix) on the establishment of white pine (Pinus strobus) and black locust (Robinia psuedoacacia) by direct seeding versus hand planting seedlings. After five years, on a minesoil derived from brown sandstone and rough-graded to reduce compaction, the tree-compatible ground cover produced more cover than the traditional ground cover, and the site index of the reclaimed land was estimated to exceed 30 m (100 ft). Based on results of this long term research program, recommendations for establishing a productive forest, capable of providing timber within a 30 year rotation are: 1) select an oxidized (brown) sandstone spoil for placement at the surface, 2) roughly grade the final surface to avoid compaction, 3) establish a tree compatible ground cover to protect the soil without overtopping trees, and 4) select an appropriate mixture of tree species and carefully plant trees by selecting good micro-sites for each seedling. / Ph. D.

A Mark IV surface force apparatus was used to measure surface forces between mica surfaces in dodecylamine hydrogen chloride (DAHCI) solutions at pH 5.7 in the presence and absence of long-chain alcohols. With DAHCI alone, only "short-range" hydrophobic forces were observed with decay lengths of 1.2-1.4 nm. In the presence of octanol, long range hydrophobic forces were observed with decay lengths in the range of 2.0-6.8 nm. In the presence of dodecanol, the decay length became as large as 9.0 nm, which represents the strongest ever recorded hydrophobic force with soluble single-chain surfactants. The appearance of the long-range hydrophobic forces in the presence of neutral surfactants can be attributed to the co adsorption mechanism, in which neutral surfactant molecules adsorb along with dodecylammonium (DAH⁺) ions on mica to form close-packed monolayers. Long-range hydrophobic forces were also measured between mica surfaces in DAHCI solutions at pH 9.5, at which considerable amount of neutral amine (DA) is produced as a result of hydrolysis. The force measurements exhibit long-range hydrophobic forces with decay length of 5.5 nm. Appearance of the long-range hydrophobic force at this pH can be attributed to the coadsorption of DA and DAH⁺ on mica. The pH where the long-range hydrophobic force appears corresponds to the pH of maximum flotation of quartz, which suggests that long-range hydrophobic force may be required for good flotation. The force measurements conducted at 10.1 show that phase-separated amine is formed on the mica surface at a 50-times lower concentration than for the bulk precipitation. Above this concentration, the mica surfaces do not jump into contact with each other, suggesting that the phase-separated amine renders the surface hydrophilic. Furthermore, the force measurements conducted at pH 10.1 show repulsive steric forces, which become stronger with increasing DAHClI concentration. The adhesion force between mica surfaces becomes zero when surface precipitation occurs, while water contact angle is less sensitive. Hydrophobic force increases sharply when advancing water contact angle (θ_α) is greater than 90°, which may be attributed to the formation of domains of close-packed monolayers of hydrocarbon chains. The domains may acquire large dipole moments, which correlate with those of the opposing surface to give rise to long-range hydrophobic forces. Alternatively, microscopic cavitation may occur on the domain, whose microscopic contact angle may be greater than 90° to satisfy the thermodynamic requirement for cavitation. / Ph. D.

Chromium(VI)-induced DNA-protein crosslinking is implicated in chromium Carcinogenicity. However, the mechanism of chromate-induced DNA-protein crosslinking has not been established. Based on the current literature and our preliminary data, we hypothesized that Cr(VI)-induced DNA-protein crosslinks may, in part, be due to generation of active oxygen species following the intracellular reduction of Cr(V1) and that antioxidants may ameliorate the genotoxic and carcinogenic effects of Cr(VI). We proposed to test our hypothesis with the following specific aims: 1) To characterize the DNA-protein complexes induced by the carcinogen Cr(VI) in MOLT4 cells, 2) To investigate the effect of Cr(VI) on "oxidative-stress status" of the cell, 3) To distinguish between proteins directly cross-linked by Cr(III) and those that are cross-linked oxidatively during intracellular Cr(VI) reduction, and 4) To identify major proteins that are complexed to DNA by Cr(III) or via oxidative mechanisms, in MOLT4 cells treated with chromate. Together, the proposed studies should provide new information regarding the mechanism of chromium genotoxicity and carcinogenicity. The identification of specific protein(s) involved in DNA-protein crosslinks may also provide an useful tool to develop biomarkers for assessment of chromium risk. The results of our studies indicate the following: (1) Characterization of chromate-induced DNA-protein complexes in MOLT4 cells: A selected group of non-histone proteins were found to crosslink to DNA upon chromate exposure. The subcellular localization of these proteins was found to be in the nuclear fraction, specifically in the nuclear matrix, suggesting the proximity of these proteins to DNA. Analysis of the stability of the crosslinks to disruptive chemicals and enzymes suggested that Cr(III) and sulfhydryl groups are partially involved in such complexes. However, resistance of some proteins to treatments such as EDTA, B-mercaptoethanol or thiourea, and their need for nuclease digestion to release them by fragmenting DNA indicated that those proteins may be covalently crosslinked to DNA via oxidative mechanisms. (2) Effect of Cr(VI) on the "oxidative-stress status" of MOLT4 cells: Chromate treatment of cells was found to not only decrease the level of low molecular weight antioxidants and antioxidant enzymes, but also induce the formation of active oxygen species, such as hydrogen peroxide. A mechanism for this hydrogen peroxide-inducing effect of chromate was proposed. A close correlation was observed between the cellular levels of oxidants and DNA-protein crosslinking following chromate exposure. Pretreatment of cells with antioxidants also illustrated correlative changes in chromate-induced DNA-protein crosslinking and the cellular level of oxidants. Intracellular generation of reactive species of chromium, such as Cr(V), and generation of active oxygen species during the reaction of Cr(VI) and its reduced forms such as Cr(V) and Cr(III), with its biological reductants were studied by EPR spectrometric techniques. Furthermore, exposure of cells to chromate was also found to induce protein oxidation and lipid peroxidation that were effectively suppressed by antioxidant pretreatment of cells, suggesting a role of reactive oxygen species, protein carbonyls and malonaldehyde in inducing DNA-protein crosslinking. (3) Detection of proteins crosslinked to DNA by direct participation of Cr(III) and via oxidative mechanisms upon chromate exposure of cells: Chromate-induced DNA-protein complexes that were formed by direct participation of Cr(III) were distinguished from those that were formed via oxidative mechanisms by using EDTA to specifically dissociate Cr(III) mediated crosslinks, and α-tocopherol succinate to suppress oxidatively crosslinked proteins, respectively. DNA-protein complexes induced by x-ray irradiation of cells and incubation of isolated nuclei with Cr(III) were used as positive controls for crosslinking of proteins to DNA by oxidative mechanisms and by Cr(III), respectively. A common group of identical non-histone proteins were found to complexed to DNA by Cr(VI), Cr(III), and x-ray, however a 51 kD basic protein appeared to be predominantly crosslinked to DNA by participation of Cr(III), while a 49 kD acidic protein appeared to be primarily crosslinked by oxidative mechanisms. Chromate-induced DNA-protein crosslinks isolated from α-tocopherol pretreated cells exhibited an increase in the fractionation of DNA by restriction enzymes as compared to that isolated from cells treated with chromate alone, further supporting the involvement of oxidative mechanisms in the process. Formaldehyde, on the other hand, primarily crosslinked histones to DNA, indicating that specificity in protein-DNA crosslinking is dependent on the chemical nature of the crosslinking agent. (4) Identification of major proteins complexed to DNA upon chromate treatment: Attempts were made to identify the proteins that crosslink to DNA upon chromate exposure of cells by using antibodies to candidate proteins, and N-terminal sequencing followed by searching for their homology in GeneBanks. Actin, lectin, and aminoglycoside nucleotidyltransferase were identified as participants in chromate-induced DNA-protein crosslinking. (5) DNA protein complexes as a biomarker of exposure to chromate: Finally, DNA-protein crosslinks were detected immunologically by developing an antiserum to chromate-induced DNA protein crosslinks. The antiserum predominantly reacted with nuclear proteins, and DNA-protein crosslinks induced by Cr(VI), Cr(III) and x-ray, but reacted poorly with formaldehyde-induced DNA-protein crosslinks, further suggesting specificity in DNA-protein crosslinks induced by different crosslinking agents. The antiserum did not react with DNA-protein crosslinks isolated from control cells. Taken together, we conclude that DNA-protein crosslinks are caused by intracellularly generated Cr(III) as well as active oxygen species formed following exposure to Cr(VI). Hence, it appears that antioxidants may be useful in reducing the genotoxic and carcinogenic effect of chromium(VI) in human populations exposed to this toxicant. Participation of the three nuclear proteins, actin, lectin, and aminoglycoside nucleotidyltransferase, in chromate-induced DNA-protein crosslinks suggest that these proteins may be parts of chromatin structure. Since these proteins are crosslinked to DNA by chromate, they may be used as biomarkers of chromate exposure. / Ph. D.

This study was conducted to determine the efficacy of Natuphos® phytase for improving the bioavailabilities of phytate P and other nutrients (CP, AA, Ca, and Zn) bound to phytate in the diets for pigs, broilers, and turkey poults, and to evaluate P and Zn equivalency values of phytase. In a 5-wk study with young pigs (BW = 7.5 kg; n = 96) fed a soybean meal-based semi-purified diet (SP), performance, P absorption, and bone characteristics were improved, as graded levels of phytase (0, 350, 700, 1,050, and 1,400 U/kg of diet) were added to the low P diets (.05 and .16% available P, aP). In comparison with the .32% aP diet, fecal P excretion decreased 25 to 50% by adding phytase. The replacement of 1 g P as defluorinated phosphate (DFP) would require about 676 U of Natuphos® phytase. Effect of phytase on Ca and N absorption were variable. Three experiments were conducted with 1,856 broilers (d 1 to 21) fed corn-soybean meal-based diets (CS, Exp. 1 and 2) or SP, (Exp. 2 and 3). A 3 x 7 factorial arrangement of treatments was used in Exp. 1 with .20, .27, and .34% nonphytate P (nP) and 0, 200, 400, 600, 800, 1,000, and 1,200 U phytase/kg of diet. Four graded levels of phytase (0, 350, 700, and 1,050 U/kg of diet) and nP (.27, .36, .45, and .54%) were used in Exp. 2 and 3 with .27% nP as a basal diet. Adding phytase consistently increased BW gain, feed intake, toe ash percentage, and apparent retention of P and Ca. The magnitude of the responses was greater with the lower nP than with the higher nP (Exp. 1). In comparison with the .45% nP diet, P excretion of broilers decreased 25 to 60% by addition of phytase. The average of P equivalency values of phytase from these three experiments indicates that the release of 1 g P as DFP requires 920 and 830 U of Natuphos® phytase for broilers fed SP and CS, respectively. Apparent N retention was increased with addition of phytase in broilers fed CS (only measured in Exp. 3). In a study with turkey poults (n = 480, d 1 to 29) fed CS, a 2 x 2 x 2 factorial arrangement of treatments was used with .45 and .60% nP, 22.5 and 28.0% CP, and 0 and 750 U of phytase/kg of diet. Microbial phytase enhanced apparent and true ileal digestibility of N and AA, apparent retention of N and P, performance and toe ash content. The major improvement of phytase on N and AA digestibility ranged from 1 to 4 percentage units was obtained at .45% nP with 28.0% CP or .60% nP with 22.5% CP. The effect of phytase on the utilization of Zn was determined in broilers (d 1 to 21, n = 384) fed a corn-soy isolate diet (20 ppm Zn). Supplemental phytase (150, 300, 450, and 600 U/kg of diet) improved Zn utilization based on measurements of Zn content in toe, tibia, and liver, apparent Zn rentention and performance. The results indicate that about 1 mg of Zn was released per 100 U of Natuphos® phytase over the range of phytase added. It was observed in pigs that the stomach was the site of highest added phytase activity. In summary, microbial phytase is effective in improving the utilization of P, Ca, Zn, N, and AA in the diets for pigs, broilers, and turkey poults. / Ph. D.

The distributions of mating alleles in local populations of the litter-decomposing agarics Marasmiellus praeacutus and Collybia subnuda were determined by mating crosses. The tetrapolar M. praeacutus has an unexpectedly low mating allele diversity at both the local and the regional level. This is probably due to a combination of factors which results in limited spore dispersal. The pattern of mating allele distribution among closely adjacent genets suggests that di-mon crossing (the Buller phenomenon) may contribute to the population structure of this species. Collybia subnuda has a mating allele diversity estimated at 45 for the species, with a 95% confidence interval of 19 to 187. On a local scale, closely adjacent genets of C. subnuda did not share mating alleles, indicating that C. subnuda is an outcrossing species. Two partially intersterile groups were identified within the C. subnuda morphospecies. They were not differentiated morphologically, geographically, or by the DNA sequence of the intergenic transcribed spacer (ITS) region of the ribosomal RNA-encoding gene family. Intersterility group (ISG) 1 is usually found on oak leaf litter, and ISG 2 is usually found associated with oak wood. Collection records, mating crosses, and spore-catching experiments indicate that the two ISGs are distributed sympatrically throughout the sampled range. Both ISGs produce binucleate spores in low frequency, and thus have the potential for secondary homothallism. Spore-catching experiments indicate that the spore rain of C. subnuda varies greatly over space and time. Spore viability studies show that C. subnuda spores have a limited viability. The implications of these observations for the population structure and speciation in C. subnuda are discussed. / Ph. D.

Cephalomannine is a naturally occurring taxane diterpenoid closely related to the potent anticancer agent Taxol. Three aspects of its chemistry were examined. First, cephalomannine was converted to Taxol. This conversion was accomplished by the reaction of a 2'- benzoyl-7-Troc cephalomannine/Taxol mixture with oxalyl chloride to generate a common oxamic acid intermediate. Treatment of this intermediate with diphenylcarbodiimide cleaved the N-oxalyl group which resulted in a spontaneous transfer of the 2'-benzoyl group to the 3'-N position. Deprotection of the 7-Troc group afforded Taxol. Second, a number of 3'-N-acyl cephalomannine and Taxol analogs were prepared and their biological activity determined. The N-tigloyl group of cephalomannine was modified by oxygenation and halogenation to yield several cephalomannine derivatives. The Taxol analogs were prepared by coupling a protected side chain to baccatin III, deprotecting, and acylating the resulting free amine. This methodology was used to prepare several oxalyl and halogenated analogs as well as N-(phenylglyoxyl) and N-crotonyl derivatives. One derivative in particular, N-debenzoyl-N-(2"-bromopropenoyl)taxol, was found to be significantly more active than Taxol. Third, Taxotere, 10- acetyltaxotere, N-debenzoyl-N-(phenoxyacetyl)taxol, and the cephalomannine diol were synthetically prepared for testing in several tubulin polymerization systems. Earlier studies had shown that some Taxol analogs had the ability to stabilize tubulin polymers to cold, but failed to induce assembly as does Taxol. The compounds prepared were used to investigate the differences and this led to the conclusion that the hypernucleation of tubulin assembly and polymer stabilization observed with Taxol represent two distinct properties of the drug. / Ph. D.

The overall goal of this research project was to synthesize poly(arylene ether)s with electron rich functional groups for use as tougheners in epoxy thermosets followed by evaluation of the miscibility of the poly(arylene ether) materials in cured epoxy thermosets. Poly(arylene ether)s were synthesized by reaction of bisphenol A with a variety of dihalo monomers including 4,4’ -difluorodiphenylsulfoxide, 4,4’- difluorodiphenylphosphine oxide, 2,6-dichloropyridine, and 4,4’- dichlorodiphenylsulfone. A novel monomer, 2,3-bis(4-fluorophenyl)quinoxaline was also synthesized and utilized to make quinoxaline-containing homopolymers and copolymers. The bisphenol A based poly(arylene ether)s: poly(arylene ether sulfoxide), poly(arylene ether pyridine) and poly(arylene ether phosphine oxide) were found to be miscible with the amine cured epoxy thermosets. Poly(arylene ether sulfone) and poly(arylene ether quinoxaline) were immiscible with the epoxy thermosets. Polymer-polymer miscibility is governed in large part by intermolecular attractive forces. To evaluate better the role that hydrogen bonding plays in the miscibility of the poly(arylene ether)/epoxy blends, a fundamental investigation of hydrogen bonding between model compounds possessing functional groups of interest (e. g. diphenylsulfone, diphenylsulfoxide, pyridine, triphenylphosphine oxide, and diphenylmethylphosphine oxide) and water was undertaken. ¹H NMR spectroscopy of model compounds in DMSO-d₆/ water (97/3) solutions was performed to ascertain the effect of the mole fraction of model compound in solution on the shift of the water peak in the ¹H NMR spectrum. In all cases, increasing mole fractions of the electron rich model compound caused the water resonance to move downfield, revealing the existence of hydrogen bonding interactions between the model compound and water. The ¹H NMR shift data were used to calculate the equilibrium constants of formation of the water-model compound hydrogen bonded complex and the shift of the proton hydrogen bonded to the model compound. The phosphine oxide containing model compounds followed no trend; however, the other model compounds were ranked as: pyridine > diphenylsulfoxide > diphenylsulfone in hydrogen bonding strength. This supports the thermal analysis data which showed that the poly(arylene ether sulfone) was immiscible with the epoxy thermoset while the poly(arylene ether sulfoxide)/epoxy system was miscible. / Ph. D.

Based on Vygotsky's theoretical construct that play creates the zone of proximal development, this study was designed to examine the processes and outcomes involved in collaboration among dyads of 4-year-olds (matched for equal and unequal levels of play) in the context of constructive play with blocks. During the first phase of data collection, 100 4-year-olds were observed in naturalistic settings using the Play Observation Scale (Rubin, 1989). Play level, gender, and unfamiliarity were used to select 48 children to play with a peer in a laboratory setting. Play sessions were videotaped and coded for block play (Reifel & Greenfield, 1982), peer interaction (Rubin, 1989), and communication (Farver, 1992). Results of an overall multivariate analysis of variance (MANOVA) conducted for boys and girls found a significant interaction between treatment (play level) and gender. A follow-up MANOVA for girls was also significant. Subsequent univariate tests found significant differences in block play complexity of girls in treatment groups. A separate pairwise MANOVA found that less-skilled girls engage in more-complex play when paired with more-skilled peers. Block play complexity and communication contributed to the differences among the groups. Results of a second pairwise MANOVA established that more-skilled girls display less-complex play behavior during play with less-skilled playmates. When considered separately, none of the dependent variables were responsible for the variance. Rather, all three contributed Simultaneously to the significant overall multivariance. For boys, an overall multivariate analysis of variance was conducted but was not statistically significant. Boys do not alter their play during play with other four-year-old boys who display different levels of play complexity. Based on these findings, play actualizes the zone of proximal development for girls, not boys. Additional scholarship is needed in this area. / Ph. D.