Thesis (M.S.)--Villanova University, 2008. / Chemistry Dept. Includes bibliographical references.

Large populations o+ black grass bugs, Labops hesperius Uhler, have been observed on extensive acreages o+ range lands. These bugs cause severe damage to the range grasses, lowering their palatability and productivity. This study was to determine whether morphological differences among breeding lines o+ grass species or interspecific hybrids could be correlated with the feeding behavior o+ black grass bugs. I+ so, plant breeders should be able to develop resistant cultivars. To explore this possibility, cultivars and synthetics o+ range grasses, representing the genera, Agropyron, Dactylis, Phalaris and Poa, were exposed to di++erent instar stages was examined under a scanning electron microscope. Leaf pubescence (trichomes) varied in density and size and appeared to be associated with resistance of plants in the genera, Agropyron, to the Labops nymphs (instar stages II and III> but had no relation with the feeding behavior of adult black grass bugs. Plant leaves of the general, Dactylis and Phalaris, were smooth (few and small if any trichomes> and were the least preferred of any of the grasses by all stages of the bugs. Trichomes on leaves of other genera were varied in density and size. Based on percent damage, preference by the nymphs was for the species with intermediate sized trichomes. The adult bugs showed no discrimination in their feeding behavior. Field grown plants developed more trichomes per unit leaf area and appeared to have thicker surface waxes than the same species grown in the greenhouse. For this reason, nymph feeding habits may be different in the field than in the greenhouse. Future studies should perhaps investigate (1) first stage nymph activity on field plants and (2) palatability and/or chemical differences of the grasses.

The dislocation etch pits formed on the cleavage surfaces of lithium fluoride in an aqueous solution containing varying concentrations of ferric ions are investigated by electron microscopy. The results obtained reveal the powerful influence of the inhibitor in the stabilisation of kinks and macroledges. There is some evidence for the nucleation of disso­lution at imperfections other than the dislocations. Dissolution spirals are observed in some cases suggesting the presence of helical dislocations in lithium fluoride. / Thesis / Master of Science (MS)

No description available.

Thesis (M. Tech.) - Central University of Technology, Free State, 2006 / Electron microscopy plays an important role in diagnostic histopathology. When this investigation is anticipated, extra tissue is submitted directly for electron microscopy. However, often it is decided only later in a problematic case to perform this investigation and then the only tissue available is embedded in the routine laboratory’s paraffin block. This tissue has to be retrieved from the wax and this entails using a clearing agent before the rest of the electron microscopy method can be implemented. Traditionally xylene is the agent that is used but has the disadvantage of being extremely toxic. This study compared the morphological effects of a relatively new and non toxic clearing agent, Tissueclear®, with that of xylene. Exposure of tissue to clearing agents for 30 minutes and overnight was performed to assess whether Tissueclear® gave better results in the long term than xylene, in the hope that the laboratory turn around time could be improved and the amount of toxic reagents used in the EM laboratory will be reduced. A second part of the study involved a questionnaire submitted to laboratory staff to assess their knowledge of xylene toxicity. Of the 325 cases submitted for electron microscopy at Universitas Hospital between January 2004 and July 2005, 140 of these had to be retrieved from paraffin wax. Four specimens were prepared from each case. Two were processed in xylene for 30 minutes and overnight and two in Tissueclear® for 30 minutes and overnight. The specimens were evaluated for consistency and resin compaction as well as ultrastructural preservation of the cell membrane, cytoplasmic content and extracellular material. The results showed that Tissueclear® and xylene gave comparable results after 30 minutes and that Tissueclear® was superior after overnight processing. This meant that a specimen submitted for electron microscopy would be processed immediately without waiting for the following morning as was the case with xylene and that the processing time for such a specimen had been shortened from 3 to 2 days. It also meant that the laboratory staff was exposed to one less toxic reagent. The results on the questionnaire showed that there were large areas of ignorance regarding toxicity as well as appropriate safety procedures that need to be followed in the laboratory. It is hoped that this study will improve awareness in this regard and encourage the use of other newer less toxic reagents.

A ordem Cetacea compreende golfinhos e baleias, mamíferos totalmente adaptados ao ambiente aquático. A língua de duas espécies de cetáceos, Pontoporia blainvillei e Sotalia fluviatilis, foram utilizadas para descrição da morfologia das papilas linguais e da superfície de interface epitélio-tecido conjuntivo da lâmina própria, empregando as técnicas de microscopia de luz e eletrônica de varredura. As línguas foram fixadas e divididas em três porções: rostral, médio e caudal e processadas conforme os protocolos das técnicas utilizadas. A língua da Pontoporia blainvillei e Sotalia fluviatilis estava revestida por um epitélio estratificado queratinizado, sendo possível observar as camadas basal, espinhosa, granulosa e córnea. Pode-se notar que na língua, o tecido conjuntivo denso apresentava vasos sanguíneos e profundamente relacionado com o tecido muscular. A superfície de interface epitélio-tecido conjuntivo da lâmina própria apresentou papilas conjuntivas de várias formas. Elas correspondem às papilas filiformes e valadas, mostrando feixes de fibras colágenas em disposição original. Na microscopia de luz polarizada revelou-se fibras colágenas do tipo I e III. No terço médio e caudal de ambas as espécies foram encontradas ácinos de glândulas salivares. As amostras tratadas com solução de hidróxido de sódio, tiveram a camada epitelial removida, e as papilas conjuntivas foram observadas em aspecto tridimensional. Foi possível observar que a superfície dorsal de ambas as espécies é totalmente recoberta por papilas conjuntivas de aspecto filiforme. Observa-se também a presença dos forames dos ductos das glândulas salivares nas porções média e caudal da língua, sendo eles mais numerosos nos filhotes. Morfometricamente, as papilas conjuntivas apresentaram maior comprimento na espécie Sotalia fluviatilis do que na Pontoporia blainville. Foi observado somente na espécie Pontoporia blainvillei estruturas conjuntivas arredondadas na região média e caudal. Embora as áreas dessas estruturas tenham sido maiores na região caudal que na média, estatisticamente estes resultados não foram significativos (P>0,05). / The Cetacea order comprises dolphins and whales, mammals totally adapted to the aquatic ambient. The tongue of two cetaceans species, Pontoporia blainvillei and Sotalia fluviatilis, was studied for description of the morphology of the lingual papillae and of interface epithelium the connective tissue surface, using the light and scanning electron microscopic techniques. The tongues were fixed and divided in three portions: rostral, medium and caudal and treated according to the protocols of techniques used. The tongues of the Pontoporia blainvillei and Sotalia fluviatilis were covered by keratinized stratified epithelium, being that is possible to verify the basal, spinosa, granular and cornetiel ayers. In the tongue the dense connective tissue of lamina propria showed blood vessels and muscular layer was deeply related. The interface epithelium-connective tissue surface of the lamina propria presented connective tissue papillae which are various in shape. They correspond to the filiform and vallate papillae showing the collagen fibers bunches in original disposition. In the polarized light microscopy revealed collagen fibers type I and III. In the medium and caudal third of both species various groupins of salivary gland acini. The samples treated with sodium hydroxide solution, the epithelial layer was removed and the connective tissue papillae were observed in three-dimensional SEM images. It was possible to observe that the dorsal surface of the both species is totally covered by connective tissue papillae of filiform aspect. We observed also the presence of the ducts of the salivary glands in the media and caudal portions of the tongue, being them more numerous in pups. Morphometric analysis showed that the connective tissue papillae presented larger length in the Sotalia fluviatilis than in the Pontoporia blainville samples. The round connectives structures in the media and caudal portions were observed only the Pontoporia blainvillei species. Although, the areas of those structures have been major in the caudal region than media, and these results were not signifficant (P>0,05).

A ordem Cetacea compreende golfinhos e baleias, mamíferos totalmente adaptados ao ambiente aquático. A língua de duas espécies de cetáceos, Pontoporia blainvillei e Sotalia fluviatilis, foram utilizadas para descrição da morfologia das papilas linguais e da superfície de interface epitélio-tecido conjuntivo da lâmina própria, empregando as técnicas de microscopia de luz e eletrônica de varredura. As línguas foram fixadas e divididas em três porções: rostral, médio e caudal e processadas conforme os protocolos das técnicas utilizadas. A língua da Pontoporia blainvillei e Sotalia fluviatilis estava revestida por um epitélio estratificado queratinizado, sendo possível observar as camadas basal, espinhosa, granulosa e córnea. Pode-se notar que na língua, o tecido conjuntivo denso apresentava vasos sanguíneos e profundamente relacionado com o tecido muscular. A superfície de interface epitélio-tecido conjuntivo da lâmina própria apresentou papilas conjuntivas de várias formas. Elas correspondem às papilas filiformes e valadas, mostrando feixes de fibras colágenas em disposição original. Na microscopia de luz polarizada revelou-se fibras colágenas do tipo I e III. No terço médio e caudal de ambas as espécies foram encontradas ácinos de glândulas salivares. As amostras tratadas com solução de hidróxido de sódio, tiveram a camada epitelial removida, e as papilas conjuntivas foram observadas em aspecto tridimensional. Foi possível observar que a superfície dorsal de ambas as espécies é totalmente recoberta por papilas conjuntivas de aspecto filiforme. Observa-se também a presença dos forames dos ductos das glândulas salivares nas porções média e caudal da língua, sendo eles mais numerosos nos filhotes. Morfometricamente, as papilas conjuntivas apresentaram maior comprimento na espécie Sotalia fluviatilis do que na Pontoporia blainville. Foi observado somente na espécie Pontoporia blainvillei estruturas conjuntivas arredondadas na região média e caudal. Embora as áreas dessas estruturas tenham sido maiores na região caudal que na média, estatisticamente estes resultados não foram significativos (P>0,05). / The Cetacea order comprises dolphins and whales, mammals totally adapted to the aquatic ambient. The tongue of two cetaceans species, Pontoporia blainvillei and Sotalia fluviatilis, was studied for description of the morphology of the lingual papillae and of interface epithelium the connective tissue surface, using the light and scanning electron microscopic techniques. The tongues were fixed and divided in three portions: rostral, medium and caudal and treated according to the protocols of techniques used. The tongues of the Pontoporia blainvillei and Sotalia fluviatilis were covered by keratinized stratified epithelium, being that is possible to verify the basal, spinosa, granular and cornetiel ayers. In the tongue the dense connective tissue of lamina propria showed blood vessels and muscular layer was deeply related. The interface epithelium-connective tissue surface of the lamina propria presented connective tissue papillae which are various in shape. They correspond to the filiform and vallate papillae showing the collagen fibers bunches in original disposition. In the polarized light microscopy revealed collagen fibers type I and III. In the medium and caudal third of both species various groupins of salivary gland acini. The samples treated with sodium hydroxide solution, the epithelial layer was removed and the connective tissue papillae were observed in three-dimensional SEM images. It was possible to observe that the dorsal surface of the both species is totally covered by connective tissue papillae of filiform aspect. We observed also the presence of the ducts of the salivary glands in the media and caudal portions of the tongue, being them more numerous in pups. Morphometric analysis showed that the connective tissue papillae presented larger length in the Sotalia fluviatilis than in the Pontoporia blainville samples. The round connectives structures in the media and caudal portions were observed only the Pontoporia blainvillei species. Although, the areas of those structures have been major in the caudal region than media, and these results were not signifficant (P>0,05).

Concrete substructures are often subjected to environmental deterioration, such as sulfate and acid attack, which leads to severe damage and causes structure degradation or even failure. In order to improve the durability of concrete, the High Performance Concrete (HPC) has become widely used by partially replacing cement with pozzolanic materials. However, HPC degradation mechanisms in sulfate and acidic environments are not completely understood. It is therefore important to evaluate the performance of the HPC in such conditions and predict concrete service life by establishing degradation models. This study began with a review of available environmental data in the State of Florida. A total of seven bridges have been inspected. Concrete cores were taken from these bridge piles and were subjected for microstructural analysis using Scanning Electron Microscope (SEM). Ettringite is found to be the products of sulfate attack in sulfate and acidic condition. In order to quantitatively analyze concrete deterioration level, an image processing program is designed using Matlab to obtain quantitative data. Crack percentage (Acrack/Asurface) is used to evaluate concrete deterioration. Thereafter, correlation analysis was performed to find the correlation between five related variables and concrete deterioration. Environmental sulfate concentration and bridge age were found to be positively correlated, while environmental pH level was found to be negatively correlated. Besides environmental conditions, concrete property factor was also included in the equation. It was derived from laboratory testing data. Experimental tests were carried out implementing accelerated expansion test under controlled environment. Specimens of eight different mix designs were prepared. The effect of pozzolanic replacement rate was taken into consideration in the empirical equation. And the empirical equation was validated with existing bridges. Results show that the proposed equations compared well with field test results with a maximum deviation of ± 20%. Two examples showing how to use the proposed equations are provided to guide the practical implementation. In conclusion, the proposed approach of relating microcracks to deterioration is a better method than existing diffusion and sorption models since sulfate attack cause cracking in concrete. Imaging technique provided in this study can also be used to quantitatively analyze concrete samples.