A intensa exposição ao Sol sujeita o lábio, principalmente o inferior, aos danos provocados pela absorção de radiação ultravioleta (UV). O carcinoma epidermoide é a neoplasia maligna que se desenvolve nos lábios após exposição crônica prolongada aos raios UV e acredita-se que todos os casos sejam precedidos pela desordem potencialmente maligna denominada queilite actínica. Ambas as lesões são causados pelos efeitos nocivos da radiação UV agindo diretamente sobre o DNA, por meio do fenômeno da fotocarcinogênese. Nesse processo, a radiação provoca mutações que são capazes de causar a iniciação, progressão e a promoção de neoplasias. No entanto, é também importante considerar que outros eventos moleculares, além das mutações, estão envolvidos na iniciação e progressão do câncer. Alterações moleculares com ganho ou perda de função de componentes da via de sinalização Notch estão envolvidas em diferentes tipos de cânceres hematológicos e sólidos. Entretanto, a participação da sinalização Notch em câncer de lábio ainda é desconhecida. Assim, o objetivo desse trabalho foi investigar se a via Notch está relacionada às lesões de queilite actínica e de carcinoma epidermoide de lábio e sua participação na fotocarcinogênese bucal. Para isso, foram utilizados 45 casos de queilite actínica, 15 casos de carcinoma epidermoide de lábio e 05 casos de lábio com aspecto de normalidade, nos quais foi analisada a expressão de Notch1 e Jagged1 por meio da técnica de imuno-histoquímica. Os resultados demonstraram que houve perda da expressão de Notch1 em 40% dos carcinomas epidermoides de lábio, sugerindo que a expressão reduzida de Notch1 pode converter os queratinócitos a um estado ativado e imaturo. Observou-se ainda, diferença nos padrões de marcação de Nocth1 e Jagged1 nas células epiteliais sugerindo que o sinal da via Notch seja transmitido a partir de uma célula apical para uma célula basal devido a localização das células que expressam o receptor e das que expressam o ligante. Concluiu-se, assim, que os resultados imuno-histoquímicos não apontam a uma regulação diferencial da expressão da proteína Notch1 e Jagged1 em lesões UV induzidas. / The intense exposure to the sun subject the lips, particularly the lower, the damage caused by the absorption of ultraviolet (UV) radiation. The squamous cell carcinoma is a malignant tumor that develops on the lips after prolonged chronic exposure to UV rays and it is believed that all cases are preceded by potentially malignant disorder called actinic cheilitis. Both lesions are caused by the harmful effects of UV radiation acting directly on the DNA, through the phenomenon of photocarcinogenesis. In this process, the radiation causes mutations that are capable of causing the initiation, progression and promotion of cancer. However, it is also important to consider that other molecular events, apart from the mutations are involved in the initiation and progression of cancer. Molecular abnormalities with gain or loss of Notch pathway components function are involved in several types of hematological and solid cancer. However, the participation of Notch signaling in lip cancer is still unknown. The objective of this study was to investigate whether the Notch pathway is related to injuries actinic cheilitis and squamous cell carcinoma of the lip and participation in oral photocarcinogenesis. For this, were used 45 cases of actinic cheilitis, 15 cases of squamous cell carcinoma of the lip and lip 05 cases with normal aspect in which we analyzed the expression of Notch1 and Jagged1 by immunohistochemistry. The results showed loss of Notch1 expression in 40% of squamous cell carcinomas of the lip, suggesting that reduced expression of Notch1 can convert to an activated keratinocytes and immature state. There was also a difference in labeling patterns of Notch 1 and Jagged1 epithelial cells suggesting that the Notch pathway signal is transmitted from an apical cell to a basal cell due to localization of cells expressing the receptor and expressing the ligand. In summary, the immunohistochemical results do not show a differential regulation of Notch 1 and Jagged1 expression in UV induced lesions.

Made available in DSpace on 2017-07-10T15:14:34Z (GMT). No. of bitstreams: 1 DissertacaoAndreiMondardo.pdf: 3159029 bytes, checksum: c8fda463ff5042449cc97ba6e2e7e0f2 (MD5) Previous issue date: 2015-10-20 / Increased consumption of processed foods and the need to consume healthier foods, it is becoming increasingly a demand for feeding the world's population. To meet the demand, industries invest heavily in technologies that can optimize manufacturing processes, invest in research for new raw materials and components to make nice food to taste, easy storage, healthy and easy to purchase. The production and especially the industrialization of food involves numerous chemical reactions, among which, even if permitted by regulatory agencies, many are still unknown. It is known that during these reactions, toxic substances can be formed to the human body or may have enhanced their toxicity thus becomes necessary to pay attention to the relationship between the consumption of these substances for long periods and the development of neoplasms. Because of this, the present study sought to know the behavior of microorganisms found in cassava starch during their modification process for food product when exposed to ultraviolet light. The objective was to evaluate the use of ultraviolet light for microbial reduction in the process of cassava starch modification. The traditional process for removing these microorganisms is by chemicals such as peracetic acid, hydrogen peroxide, hydrochloric acid and others. With this study it was possible to reduce the percentage of microorganisms according to the same exposure time to UV light. It was rated the starch viscosity behavior during the reaction and also the Bacillus Cereus behavior, Yeast and Molds, coliforms Termoselantes, Mesophiles and Salmonella. Applying a UV irradiation dose of 43,2 mW.s.cm-2, in treatment T40 gave effectiveness on reducing the microorganism Bacillus 99.82% to 100% for yeasts and molds, 99.99% termoselantes for coliforms and 99.98% for mesophilic. / O aumento do consumo de alimentos industrializados e a necessidade de se consumir alimentos mais saudáveis, está se tornando cada vez mais uma demanda para a alimentação da população mundial. Para atender à demanda, as indústrias investem em tecnologias que possam otimizar os processos de fabricação, investem em pesquisas em busca de novas matérias-primas e compostos para tornar os alimentos agradáveis ao paladar, de fácil armazenamento, saudáveis e de fácil aquisição. A produção e principalmente a industrialização de alimentos envolve inúmeras reações químicas, dentre as quais, mesmo sendo permitidas pelos órgãos reguladores, muitas ainda são desconhecidas. Sabe-se que, durante tais reações, podem ser formadas substâncias tóxicas ao organismo humano ou podem ter sua toxicidade intensificada, dessa forma, se torna indispensável atentar para a relação entre o consumo dessas substâncias por longos períodos e o desenvolvimento de neoplasias. Devido a isso, o presente estudo, buscou conhecer o comportamento dos microrganismos encontrados na fécula de mandioca durante seu processo de modificação para produto alimentício, quando exposta à luz ultravioleta. Seu objetivo foi avaliar o uso da luz ultravioleta para redução microbiológica no processo de modificação de amido de mandioca. O processo tradicional para remoção desses microrganismos é através de produtos químicos como ácido peracético, peróxido de hidrogênio, ácido clorídrico entre outros. Com esse estudo foi possível conhecer o percentual de redução de microrganismos em função do tempo de exposição do mesmo à luz UV. Foi avaliado o comportamento da viscosidade do amido durante a reação e também o comportamento de Bacillus Cereus, Bolores e Leveduras, Coliformes Termoselantes, Mesófilos e Salmonelas. Aplicando-se uma dose de irradiação UV de 43,2 mW.s.cm-2, no tratamento T40 obteve-se eficiência na redução dos microrganismos de 99,82% para bacilus, 100% para bolores e leveduras, 99,99% para coliformes termoselantes e 99,98% para mesófilos.

We developed an extreme ultraviolet (EUV) polarimeter, which employs laser-generated high-order harmonics as the light source. This relatively high-flux, directional EUV source has available wavelengths between 10 nm and 47 nm with easily rotatable linear polarization. The polarimeter has allowed us to characterize the optical constants of materials that may be useful for EUV optics. The instrument has a versatile positioning system and a spectral resolution of about 180, and we have demonstrated that reflectance as low as 0.1% can be measured repeatably at EUV wavelengths. We investigate the high harmonic source used for polarimetry measurements by documenting the spatial evolution of the generating laser in a semi-infinite helium-filled gas cell under conditions suitable for harmonic generation. The laser is observed to focus, diverge, and refocus, accompanied by a flattop beam profile and extended harmonic phase matching. We numerically simulate the propagation to investigate these experimental results. We find that harmonic energy comes from the forward portion of the laser pulse, whereas the latter portion gives rise to the incidental double laser focusing. Good phase matching for the harmonics arises in large measure from a balance between the linear phase delay of the neutral atoms and the Gouy shift, which is elongated and nearly linearized when an aperture is partially closed on the beam. We compare reflectance data taken with the polarimeter instrument with expected results from well-characterized samples and find that they agree. To improve repeatability and reduce the effects of systematic measurement errors we have measured the ratio of p- to s-polarized reflectance and shown that optical constants can be extracted from this data as efficiently as from absolute reflectance measurements. These ratio measurements allow more accurate recovery of optical constants than our absolute reflectance measurements for our well-characterized samples. We use the polarimeter instrument and the ratio reflectance technique to determine the optical constants of copper, uranium, and their natural oxides from 10-47 nm. For copper, this measurement resolves previously conflicting data sets, where disagreement on optical-constant values arises from failure to keep samples from oxidizing before measurement. Uranium has been proposed as a high-reflectance material in the EUV for several years, however difficulties with oxidation have prevented its careful characterization previous to this work. We find that measured optical constants for uranium do not agree well with previously accepted theoretical calculations.

Plant acclimation to natural and intensified solar UV-B irradiance was investigated in three species, Oenothera stricta Ledeb., Rumex obtusifolius L., and R . patientia L. The objectives of this study were to determine: (1) the relationship between plant sensitivity and epidermal UV attenuation, (2) the effect of phenotypic changes in the leaf epidermis, resulting from UV-B exposure, on plant sensitivity to UV radiation, and (3) the plasticity of these changes in the epidermis leading to plant acclimation to UVB radiation. Epidermal UV transmittance was found to differ in magnitude and spectral distribution among the three species examined in this study. Epidermal tissue from the leaves of Oenothera stricta, Rumex obtusifolius, and R. patientiaattenuated up to 951, 90%, and 851 of the UV-B radiation incident on the leaf, respectively. The spectral distribution of transmittance appeared to be characteristic of each species. The capacity of the epidermis to attenuate UV-B radiation was found to have some degree of plasticity in Oenothera stricta and Rumex obtusifolius. After exposure to UV-B radiation for periods of 11 to 15 days, at a mean dose rate of approximately 2050 biologically effective J·m·-2d-1 , epidermal UV-B transmittance was significantly reduced by up to 36% in mature leaves of O. stricta. Increased capacity of the epidermis to attenuate UV-B radiation was not observed in young leaves of this species. These leaves only transmitted about 4% of the UV-8 radiation incident on the leaf, The transmittance of shorter wavelengths of visible radiation was reduced by 6 to 14% in young and mature leaves after UV-B irradiation. A similar reduction in epidermal UV-8 transmittance in the leaves of R. obtusifolius was also observed. Ultraviolet absorbance in leaf epidermal and mesophyll tissue of Oenothera stricta generally increased in response to UV-B irradiation. Absorbance increased more in young leaves than mature leaves after UV-B irradiation. This increase in UV absorbance was also found in mature leaves of Rumex obtusifolius and R. patientia after UV-B irradiation. The increase in absorbance was most likely caused by an increase in flavonoid and related phenolic compounds in leaf tissues. The rate of photosynthesis was used as an indicator of the degree of plant sensitivity to UV-B radiation. In general, photosynthesis was not significantly depressed in the leaves of any of the three species. A trend toward photosynthetic depression in response to UV-B irradiation was found, however, and thus some degree of UV-B sensitivity is suggested in these species. A limited degree of plant acclimation was suggested in plants that were exposed to a low UV-B dose rate prior to a higher dose rate. A mechanism of UV-B attenuation, possibly involving the biosynthesis of UV-ab sorbing flavonoid compounds in the epidermis and mesophyll under the stress of UV-B radiation, and a subsequent increase in the UV-B attenuation capacity of the epidermis, is suggested. The degree of plant sensitivity and acclimation to natural and intensified solar UV-B radiation may involve a dynamic balance between the capacity for UV-B attenuation and UV-radiation-repair mechanisms in the leaf.

The generation of high-order harmonics opened an era of attosecond science wherein coherent light bursts are used to probe dynamic processes in matter with a time resolution short enough to resolve the motions of electrons. It enabled the development of extreme ultraviolet (XUV) and X-ray table-top sources with both temporal and spatial coherence, which provides the ability to shape the temporal and spatial structure of the XUV pulses. Scientists developed techniques to control and measure the temporal structure high harmonic emissions. These techniques exploited control of the driving laser pulse in the time domain and facilitated development of more advanced high-harmonic based XUV sources that have greatly impacted ultrafast measurements. In this thesis, I apply techniques to control and measure the spatial structure of high harmonic emissions, and discuss the underlying physics and potential applications of the interaction between spatially structured laser beams and materials. This study exploits the spatial degree of freedom in strong field interaction, which has not been given as much attention as the temporal degree of freedom. I use liquid crystal devices to shape the wave front of a fundamental laser beam to a vortex structure, then imprint this structured wave front onto XUV beams through high harmonic generation. This method provides an alternative to special XUV optics, which can manipulate the wave front of XUV radiation by all optical means. This result also reveals the conservation of orbital angular momentum in this extreme nonlinear wave mixing process. In addition to shaping the wave front, shaping the polarization of the driving beam also allows generation of circularly polarized the XUV radiation using a high harmonic source. This thesis also highlights the interplay between shaping the wave front and polarization in the high harmonic generation process. The topology of the structured beam can be maintained through this extreme nonlinear interaction due to the spin selection rules and spin-orbit conservation. Moreover, this thesis demonstrates an approach to integrate a vector beam into a broadband ultrafast light source and overcome the bandwidth limitation of mode converters. We use this approach to generate a few-cycle structured beam. In the future, this beam will be used to generate a strong ultrafast magnetic impulse in gas and solid targets by driving currents in a loop, which is a valuable tool for the future of magnetic metrology. The novel properties of structured laser beams discussed in this thesis expanded the capabilities of high harmonic based XUV sources and have opened a new field to explore this additional degree of freedom in strong field interactions.

Bibliography: leaves 267-287.

Excess exposure to solar ultraviolet radiation (UVR) is the only readily modifiable skin cancer risk factor, and childhood exposure is implicated in melanoma aetiology. To assist the design and evaluation of child sun protection interventions in the school and community context, this first comprehensive study used electronic monitors to record time-stamped, second-by-second UVR exposure of 325 children (from 28 randomly selected New Zealand primary schools) who kept a diary record of concurrent activities and sun-protective practices and completed a sun-related knowledge, attitudes and usual behaviours questionnaire. School principals and Health promoters (HPs) were interviewed about school and community sun protection efforts. Using the Haddon matrix and Ottawa Charter of Health Promotion to guide research, four potential domains of influence were identified: the physical and social environments, protective products, and host (child). Two key outcomes identified were child UVR exposure and sun-protective practices. A path model was developed where potential influences on these outcomes included school, community, host factors (demographics, skin type, sun-related attitudes, and sun-related knowledge), and pattern of concurrent outdoor activity. Seven specific hypotheses were defined to investigate the effects of host, school and community factors on UVR exposure, sun-protective practices, and sun-related knowledge, attitudes and behaviours. To test for the effects of host factors, day of the week and activity on UVR exposure and sun-protective practices, linear mixed models containing these factors and interactions between Year level-sex, activity-Year level and activity-sex, accounting for clustering within schools and allowing for repeated measures, were applied. Logistic regression with a random school effect was used to assess differences in scored student questionnaire items. Structural equation modelling was implemented to consider associations between sun-related knowledge, attitudes and behaviours, and other explanatory factors for variations in UVR exposure and sun-protective practices. Three of the seven specific hypotheses were supported. There were statistically significant differences in UVR exposure by sex, skin type, day of the week and activity, and sex-activity and Year level-activity interactions. Passive pursuits were associated with the highest UVR exposure rates compared to outdoor active, travel and unclassified pursuits. There were statistically significant differences in sun-protective practices by sex, ethnicity and skin type, and sex-activity and Year level-activity interactions. Girls tended to have higher sun protection scores than boys, but were more likely to sunbathe and use sunscreen. Children identifying with Pacific Island ethnicities had higher scores than children with other ethnicities, and children with Fitzpatrick skin types I and II had higher scores than children with skin types III, IV and V. School and community factors were not associated with UVR exposure, sun-protective practices, sun-related knowledge, attitudes and behaviours, but school and HPs� scores were relatively high, reflecting the significant time and effort spent promoting youth sun protection. Trends for Year level indicated that whereas child sun-related knowledge increased with Year level, attitudes and behaviours supportive of sun protection declined. When considering sun-related knowledge, attitudes and behaviours simultaneously, knowledge was only significantly associated with behaviours when mediated by attitudes. The study findings have implications for child sun protection interventions.

This study presents findings on the effect of domestic laundry detergents on the fastness to light of selected fibre reactive dyes applied to cotton. The study was carried out to elucidate the reasons for the accelerated colour loss of cotton garments washed under Australian domestic laundering conditions. Cotton fabric dyed with commonly used reactive dyes were laundered with water only, several domestic detergents and a laboratory formulated neutral detergent, and then exposed to light for two hours in the wet state. Quantities of detergent used were in accordance with the manufacturers recommendations. Exposures were repeated fifteen times equivalent to 30 hours exposure. Colour loss and colour difference were measured after 5, 10 and 15 wash cycles and 10, 20 and 30 hours exposure. When the fabric was exposed wet the colour faded more rapidly than when exposed dry to light. Detergents increased the colour loss even when the fabric was not exposed to light. The presence of an oxidizing bleach (sodium perborate) in the detergent increased colour loss during washing and wet exposure to light. Ultraviolet radiation from the light source, heat, moisture, alkali and oxidising bleach during exposure resulted in hydrolysis of the dye-fibre bond causing dye desorption during washing and rinsing. Water alone increased the fading of the dyes most likely due to presence of dissolved oxygen held within the fibre. The combination of ultraviolet radiation and oxidizing bleaches altered the chemistry of the dye and hence its shade. This was particularly evident on the black dye and one of the navy blue dyes.

Le travail présenté dans ce rapport a pour objectif d'étudier la faisabilité d'un laser à semi-conducteurs III-nitrures pompé par cathode à micropointes émettant dans l'UV lointain (250–350 nm). La structure laser, élaborée en EJM, est une hétérostructure à confinement séparé dont la zone active est constituée de puits (ou boîtes) quantiques de GaN dans une barrière d'AlxGa1-xN. Elle est pompée par un faisceau d'électrons énergétiques (~10 keV) générés par une cathode à micropointes. Le faisceau électronique converge sur la structure laser grâce à des aimants permanents qui impriment aux électrons un mouvement cyclotron. Cette étude a mis en évidence deux verrous technologiques dans la réalisation de ce laser. Premièrement, le seuil laser est très élevé (~10 MW/cm 2 en pompage optique). En effet, la qualité des alliages AlxGa1-xN constituant la barrière est insuffisante, ce qui se traduit par un faible transfert des porteurs vers les puits quantiques. Des mesures de cathodoluminescence ont été couplées à des simulations pour étudier la diffusion ambipolaire dans les hétérostructures. La longueur de diffusion varie sur trois ordres de grandeur (~nm–μ m) selon la couche étudiée. Elle est la plus faible dans la barrière d'Al0.1Ga0.9N. L'utilisation de substrats de SiC face carbone a permis d'améliorer la qualité des échantillons. Deuxièmement, le courant émis par les micropointes (~A/cm 2 ) est insuffisant pour atteindre le seuil laser. Un dispositif de dépôt de césium sur les micropointes a été mis au point afin de réduire le travail de sortie des électrons. On a ainsi pu multiplier le courant émis par un facteur 50 pour une tension grille–cathode de 70 V mais le dépôt de césium est inhomogène et instable.

L'étude des relations Soleil-Terre est une science en pleine effervescence, tant à cause des problèmes physiques qu'elle souléve que par son impact grandissant sur nos sociétés, ce dernier cas étant illustré par l'émergence de la météorologie de l'espace. Dans ce cadre, cette thèse s'emploie à mieux connaître et modéliser le flux extrême ultraviolet (EUV) solaire, principal créateur de l'ionosphère diurne terrestre et plus généralement planétaire. Un traitement routinier original des mesures du spectromètre SUMER à bord de SOHO permet d'obtenir une statistique considérable sur l'émission des raies EUV dans les régions calmes et les trous coronaux de l'atmosphère solaire, répartie sur une fraction significative du cycle d'activité solaire de onze ans. La quantité de données réduites permet ensuite l'étude du réseau de la zone de transition au cours du cycle, montrant qu'il n'est pas observé de variations importantes de la structure réseau/cellules avec l'activité solaire. En utilisant ces résultats, nous calculons les mesures différentielles d'émissions (DEM), puis les spectres EUV synthétiques pour les 2 composantes de l'atmosphère solaire citées plus haut. La comparaison avec les données TIMED/SEE d'un calcul du flux solaire EUV basé sur ces 2 spectres et sur celui d'une région active rend la démarche convaincante. Nous étendons ensuite le concept de la DEM au soleil entier, et calculons ainsi le flux EUV à partir de la mesure de l'irradiance de 5 raies solaires, sur 100 jours. La comparaison sur l'ensemble du spectre avec les données de TIMED/SEE est encourageante.