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A new multi-purpose surface analytical instrument (the Hallam instrument) is described, which combines the surface specific information obtained using x-ray photoelectron spectroscopy (XPS), with bulk information obtained using Energy Dispersive X-ray (EDX) detection. A 15kV electron gun and an ultra high vacuum EDX detector give the instrument an EDX mapping capability. To exploit this to its full potential, spatial alignment of EDX maps acquired at various electron beam energies, E[o], was required. The misalignment of images acquired at various E[o] values was investigated, and a means of describing the misalignment as a function of E[o] was presented. An algorithm was developed which would allow the alignment of offline images acquired at different E[o] values. This was demonstrated on images acquired on both the Hallam instrument and on a Phillips XL40 electron microscope. The small area XPS system developed by Kratos analytical gave a spatial resolution of 30pm at the centre of the field of view, although this deteriorated away from the centre. The reasons for this deterioration in spatial resolution were investigated, and two methods of improving the system were presented. The improvements were implemented on the Hallam instrument and demonstrated using a standard silver grid sample. The small area XPS was applied to a TiAINi coated stainless steel sample to demonstrate its application to real samples, and to display the spatial alignment between the XPS and EDX maps. Finally, the instrument was calibrated for quantitative XPS studies. This involves determining the response of the instrument as a function of the photoelectron kinetic energy. From several methods presented in the literature, the most appropriate was chosen for calibration of the 'Hallam' instrument. The effectiveness of the method used was assessed by recording spectrum intensity from pure elemental standards, and comparing the results with intensity values calculated using the calibration curves.

Cada vez mais, estudos ressaltam os efeitos nocivos da radiação advinda de exames radiográficos, chamando atenção para o risco que podem representar à saúde dos indivíduos. Tendo em vista as inúmeras alterações celulares derivadas das exposições aos raios X, foi objetivo deste trabalho avaliar a ação de 12 R de radiação X, aplicados semanalmente em camundongos, desde uma idade precoce até a vida adulta, analisando a sua ação nas células a partir do desenvolvimento mandibular. Para tanto, foi realizado um estudo experimental utilizando 90 camundongos machos com 6 semanas de vida, tendo um grupo-controle (G1 – 40 animais), um grupo que foi exposto à radiação semanalmente durante 30 semanas (G2 – 40 animais) e um grupo de 10 animais, (G0) que foi utilizado para o estabelecimento das medidas mandibulares iniciais de controle. Ao término do experimento, os animais foram anestesiados e mortos por decapitação sendo suas mandíbulas removidas para serem dissecadas. Posteriormente, estas foram fotografadas com máquina digital utilizando parâmetros específicos e, através do software Image Tool, foram realizadas seis medidas mandibulares. A análise de variância múltipla considerando as seis medidas como variáveis dependentes mostrou diferença estatística significativa para todas as medidas. Através dos resultados obtidos, pôde-se detectar a interferência da radiação X em doses baixas e periódicas como agente externo, causando diminuição do crescimento ósseo em mandíbulas de camundongos durante o envelhecimento. Assim, é possível concluir que existe associação entre exposição crônica à radiação X e redução no crescimento mandibular de camundongos (p<0,05). / Studies have increasingly stressed the negative effects of radiation from X-ray examinations, and have drawn attention to the risk it may represent to patient health. Several cell changes occur due to exposure to X-rays. The purpose of this study was to evaluate the effect of low-dose X –ray exposure on cells from an early age to adulthood by analyzing mandibular development. An experimental study was conducted with 90 six-week-old male mice divided into a control group (G1 – 40 animals), a group exposed to radiation weekly for 30 weeks (G2 – 40 animals) and a group of 10 animals (G0) used to define initial control mandibular measures. After the experiment, the animals were anesthetized and beheaded, and their mandibles were removed for dissection. The mandibles were then photographed digitally using specific parameters. The Image Tool software was used to obtain six mandibular measures. Multiple analysis of variance using the six measures as dependent variables showed a statistically significant difference in all measures. Results showed that there is an association between chronic X-ray exposure and reduction in mandibular growth in mice (p<0.05).

Cada vez mais, estudos ressaltam os efeitos nocivos da radiação advinda de exames radiográficos, chamando atenção para o risco que podem representar à saúde dos indivíduos. Tendo em vista as inúmeras alterações celulares derivadas das exposições aos raios X, foi objetivo deste trabalho avaliar a ação de 12 R de radiação X, aplicados semanalmente em camundongos, desde uma idade precoce até a vida adulta, analisando a sua ação nas células a partir do desenvolvimento mandibular. Para tanto, foi realizado um estudo experimental utilizando 90 camundongos machos com 6 semanas de vida, tendo um grupo-controle (G1 – 40 animais), um grupo que foi exposto à radiação semanalmente durante 30 semanas (G2 – 40 animais) e um grupo de 10 animais, (G0) que foi utilizado para o estabelecimento das medidas mandibulares iniciais de controle. Ao término do experimento, os animais foram anestesiados e mortos por decapitação sendo suas mandíbulas removidas para serem dissecadas. Posteriormente, estas foram fotografadas com máquina digital utilizando parâmetros específicos e, através do software Image Tool, foram realizadas seis medidas mandibulares. A análise de variância múltipla considerando as seis medidas como variáveis dependentes mostrou diferença estatística significativa para todas as medidas. Através dos resultados obtidos, pôde-se detectar a interferência da radiação X em doses baixas e periódicas como agente externo, causando diminuição do crescimento ósseo em mandíbulas de camundongos durante o envelhecimento. Assim, é possível concluir que existe associação entre exposição crônica à radiação X e redução no crescimento mandibular de camundongos (p<0,05). / Studies have increasingly stressed the negative effects of radiation from X-ray examinations, and have drawn attention to the risk it may represent to patient health. Several cell changes occur due to exposure to X-rays. The purpose of this study was to evaluate the effect of low-dose X –ray exposure on cells from an early age to adulthood by analyzing mandibular development. An experimental study was conducted with 90 six-week-old male mice divided into a control group (G1 – 40 animals), a group exposed to radiation weekly for 30 weeks (G2 – 40 animals) and a group of 10 animals (G0) used to define initial control mandibular measures. After the experiment, the animals were anesthetized and beheaded, and their mandibles were removed for dissection. The mandibles were then photographed digitally using specific parameters. The Image Tool software was used to obtain six mandibular measures. Multiple analysis of variance using the six measures as dependent variables showed a statistically significant difference in all measures. Results showed that there is an association between chronic X-ray exposure and reduction in mandibular growth in mice (p<0.05).

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