CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Os primers sÃo tintas primÃrias que funcionam como fundo anticorrosivo quando aplicados sobre metais. As suas propriedades anticorrosivas devem-se os pigmentos usados na sua composiÃÃo, sendo os mais comuns o zarcÃo, o cromato de zinco, o Ãxido de ferro e o pà de zinco. As tintas à base de resina epoxÃdica sÃo bastanteutilizadas como primers, pois apÃs a cura estas tornam-se impermeÃveis e, quandosÃo associadas a pigmentos com propriedades anticorrosivas, aumentam a resistÃnciado substrato à corrosÃo. PelÃculas secas de tintas-primers formuladas com resinaepoxÃdica DGEBA (Ãter Diglicidil de Bisfenol A), reticuladas com umapoliaminoamida (Versamid 125), e com dois pigmentos anticorrosivos, um tÃxico (cromato de zinco) e outro nÃo-tÃxico (sÃlica trocadora de cÃlcio) foram estudadas atravÃs das tÃcnicas de termogravimetria (TG), infravermelho (FTIR) e microscopia eletrÃnica de varredura (MEV). AtravÃs de TG foram determinados parÃmetros cinÃticos, como a Energia de ativaÃÃo, tanto pelo mÃtodo de Ozawa-Wall-Flynn, quanto de Kissinger. Verificou-se que o mecanismo de degradaÃÃo das tintas epoxidÃcas à alterado na presenÃa dos pigmentos. A estabilidade termo-oxidativa do primer com cromato de zinco, baseada nos valores de IPDT, à menor do que a do primer com o pigmento silica cÃlcio. A imersÃo dos primers em Ãcido clorÃdrico, nas concentraÃÃes de 10-5 atà 6,0M, reduz a estabilidade tÃrmica, sendo o mais afetado aquele contendo cromato de zinco. Neste ocorre a formaÃÃo de poros, detectados pela MEV. O uso do pigmento anticorrosivo sÃlica cÃlcio apresenta, alÃm da vantagem da nÃo toxidade, maior estabilidade termo-oxidativa e maior resistÃncia a ambientes Ãcidos do que o pigmento cromato de zinco. / The primers are primary anticorrosive dyes, with anticorrosive property due to the presence of appropriate pigment. The most common used anticorrosive pigments are zarcÃo, zinc chromate, iron oxide and zinc powder. Paints based on epoxy resin are very used as primers, because their impermeability and, when associated with anticorrosive pigments, the increase in the resistance against corrosion. Films of paint-primers formulated with DGEBA epoxy resin (Diglycidyl Ether of Bisphenol A), crosslinked with polyaminoamida (Versamid 125) , and with two anticorrosive pigments, zinc chromate (toxic) and calcium silicate (not toxic), were studied by thermogravimetric analysis (TG), infrared spectroscopy (FTIR) and scanning electronic microscopy (SEM). Kinetic parameters, such as activation energy, were calculated by TG, using Ozawa-Wall-Flynn and Kissinger methods. Change in the mechanism of epoxy paint degradation was observed in the presence of the two pigments. Primer with calcium silicate was more thermally stable than that with zinc chromate, based on IPDT values. The immersion of primers films in hydrochloric acid in the concentrations range from 10-5 to 6,0 M led to a decrease in the thermal stability. The most affected primer was that with zinc chromate, in which porous was detected by SEM after the immersion in acid solution. The primer with calcium silicate has the advantage of being more thermally stable and more resistant to acid attack, in addition to its more important ecological property, the non toxicity.

Monascus é um fungo ascomiceto tradicionalmente utilizado na China. Os povos orientais utilizam o produto de sua fermentação em arroz não aglutinado, ao qual dão o nome de \"Ang-kak\", e no inglês, \"Red yeast rice\". Sabe-se que este extrato contém substâncias hipocolesterolêmicas, como a Monacolina K, inibidor competitivo da enzima HMG-CoA. Este trabalho se insere neste contexto uma vez que consiste na otimização da fermentação e secagem do extrato de Monascus ruber. Embora já existam estudos sobre a atividade biológica deste extrato, os quais comprovam seus benefícios, não há muitos estudos que visam otimizar a sua fermentação em meio submerso e a secagem do extrato. Para tanto, foram avaliados diversos parâmetros na fermentação através de dois planejamentos fatoriais. No primeiro planejamento, as variáveis estudadas foram o meio de cultura (meio arrozina-glicose e meio sólido de arroz) e agitação (0 rpm e 10 rpm). A agitação promoveu um leve aumento na produção de monacolina-K, já o meio líquido foi mais eficiente na produção desta substância do que o meio sólido de arroz. Baseado neste experimento escolheu-se o meio fermentativo para os demais estudos. No segundo experimento as variáveis estudadas foram a adição no meio arrozina-glicose de zinco, amônio e glutamato. Neste experimento pôde-se verificar que o a produção de monacolina K e de pigmentos foi maior no meio com concentrações intermediárias de zinco e de glutamato e com concentrações maiores de amônio. No estudo da secagem, realizou-se um planejamento Box Benkhin, a fim de se avaliar a influência da proporção do adjuvante: fármaco, do tempo de incorporação do excipiente e da temperatura sobre características do extrato seco como: densidade aparente, densidade de compactação, fator de Hausner, umidade residual, atividade de água, atividade antioxidante e teor de monacolina K. Em relação à proporção do adjuvante: droga pode-se afirmar que a menor produz pós com menor atividade de água e teor de umidade, porém todos os pós obtidos tiveram seu teor de umidade e atividade de água dentro do ideal e a análise estatística mostrou que a proporção do adjuvante: droga não influenciou de forma significativa a atividade de água e o teor de umidade; a proporção 7,5:1 produz melhor rendimento e pós com melhores propriedades de fluxo, por possuírem menores valores de índice de compressibilidade e fator de hausner, já com a proporção 10:1 fornece pós com maior teor de monacolina e maior atividade antioxidante. Em relação à temperatura pode-se afirmar que utilizando-se 50°C obteve-se pós com melhores propriedades de fluxo, ou seja, menor índice de compressibilidade e menor e fator de hausner. Utilizando temperatura de 80°C obteve-se menor atividade antioxidante, maior rendimento e maior teor de monacolina K. Contudo, a análise estatística mostrou que a temperatura não influenciou de forma significativa o teor de monacolina K. Com uma temperatura maior, 110°C obteve-se menor teor de umidade e maior teor de pigmentos vermelhos. Em relação ao tempo de mistura do adjuvante pode-se afirmar que com 1 minuto obteve-se maior teor de pigmentos e pós com melhores propriedades de fluxo, com 5 minutos obteve-se menor teor de pigmentos, maior rendimento, maior teor de monacolina K e menor atividade de água, já com 10 minutos obteve-se menor teor de umidade e maior porcentagem de inibição. A análise estatística demonstrou que o tempo de mistura não influencia de forma significativa a atividade antioxidante. / Monascus ruber is an ascomycete fungus traditionally used in China. Eastern peoples use the product of its fermentation in rice non-agglutinated, which they call Ang-kak (red yeast rice, in English). It is known that this extract contains hypocholesterolemic substances such as the Monacoline K, a competitive inhibitor of the HMG-CoA enzyme. This work comes into this context since it consists in the optimization of the fermentative and drying processes of the Monascus rubers extract. Despite the existence of studies on the biological activity of this extract, which support its benefits, not many aimed at optimizing the fermentative process in submerged conditions and the drying of the extract. This work aimed at optimizing the fermentative process and the drying of the Monascus rubers extract. In order to do such, several parameters of the fermentative process were evaluated through two factorial plannings. In the first one, the variables studied were the modes of culture (liquid culture and solid-state culture) and agitation (0 rpm and 10 rpm). Agitation led to a slight increase in the production of Monacoline-K, and the liquid culture was more efficient in the production of this substance than the solid-state culture. Based on these findings, the fermentative substrate for the following experiments was chosen. In the second experiment, the variables studied were the addition of zinc, ammonium and glutamate in the liquid culture. It was observed that the production of monacoline-k and pigments was increased in the substrates with intermediary concentrations of zinc and glutamate and higher concentration of ammonium. In the drying study, a Box-Benkhin planning was adopted in order to assess the influence of the adjuvant: drug proportion, excipient incorporation time and temperature over the characteristics of the dried extract, such as: apparent density, compactation density, Hausner factor, residual humidity, water activity, antioxidant activity and monacoline-K levels. Regarding the adjuvant: drug proportion, it can be stated that the 5:1 proportion produces powders with smaller water activity and humidity levels, however, all the powders obtained presented humidity levels and water activity within the ideal and, besides that, the statistical analysis showed that the adjuvant: drug proportion had no significant influence on water activity or humidity levels; the proportion of 7,5:1 produces greater quantities and powders with better flow properties, since they have lower values of IC and FH; and with the proportion of 10:1, powders with higher levels of monacoline-K and greater antioxidant activity can be obtained. Concerning temperature, it was observed that powders with better flow properties (lower IC and FH) were obtained at 50°C. At 80°C, lower antioxidant activity, greater quantities and higher levels of monacoline-K were observed, however, the statistical analysis showed that the temperature had no significant effect on the levels of monacoline-K. With a higher temperature (110°C), lower humidity levels and higher red pigment levels were obtained. Concerning the mix time adjuvant: drug proportion, it can be stated that with 1 minute higher levels of pigment and powders with better flow properties were obtained; lower levels of pigment, greater quantities, higher levels of monacoline-K and lower water activity were obtained with 5 minutes and; lower humidity level and greater percentage of inhibition were observed with 10 minutes, however, the statistical analysis showed that the mix time has no significant influence on the antioxidant activity.

Em arqueometria e nas ciências aplicadas, metodologias físicas e químicas são de grande utilidade para estudar diferentes materiais e objetos do patrimônio cultural como pinturas de cavalete, murais, cerâmicas, metais, etc. No caso particular de pinturas, tais análises podem auxiliar na compreensão do processo criativo, dos materiais utilizados pelo artista e do estado de conservação desta obra. No contexto deste último item, podem ser caracterizados sinais de degradação, como a alteração de cores. Dentro do objetivo de compreender a degradação de alguns pigmentos por exposição luminosa, estudaram-se os pigmentos amarelo de cádmio (CdS), amarelo de cromo (PbCrO4), azul de cobalto (CoAl2O4) e cerúleo (Co2SnO4), sendo estes dois últimos também misturados ao branco de zinco (ZnO). Tais estudos foram realizados através de três ensaios com amostras padrões preparadas com estes pigmentos: fotodegradação induzida na linha TGM (Toroidal Grating Monochromator) do Laboratório Nacional de Luz Síncrotron; exposição à luz ultravioleta no simulador solar SOL-UV; e exposição às radiações ultravioleta, visível e infravermelha em uma câmara projetada neste mestrado. Os resultados apontaram para indicativos de alteração em todas as amostras, em especial mudanças no espectro de reflectância na região do visível. Por fim, analisaram-se amostras de tintas obtidas de obras do pintor Candido Portinari que possuíam indícios de alteração cromática. A partir destes fragmentos, construíram-se modelos estratigráficos dos materiais utilizados pelo artista nestas pinturas. / In archeometry and applied sciences, physical and chemical methodologies are very useful for studying different materials and objects of cultural heritage such as easel paintings, murals, ceramics, metals, etc. In the particular case of paintings, such analyses can help in understanding the creative process, the materials used by the artist and the conservation status of this work. In the context of this latter item, signs of degradation, such as color change, can be characterized. In order to understand the degradation of some pigments by light exposure, the cadmium yellow (CdS), chrome yellow (PbCrO4), cobalt blue (CoAl2O4) and cerulean blue (Co2SnO4) pigments were studied, the latter two being also mixed with zinc white pigment (ZnO). Such studies were carried out through three experiments prepared with these pigments: photodegradation induced in the TGM (Toroidal Grating Monochromator) line of the National Laboratory of Synchrotron Light; exposure to ultraviolet light in the SOL-UV solar simulator; and exposure to ultraviolet, visible and infrared radiation in a chamber designed in this master\'s degree. The results pointed out changes in all samples, especially in their reflectance spectrum in the visible region. Finally, samples obtained from works by the painter Candido Portinari that had signs of chromatic alteration were analyzed. Based on these fragments, stratigraphic models of the materials used by the artist in these paintings could be constructed.

Orientador: Délia B. Rodrigyez-Amaya / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-20T09:15:02Z (GMT). No. of bitstreams: 1 Cecchi_HeloisaMascia_M.pdf: 3005651 bytes, checksum: 1cfac7978935b58a70a3ab052512ed0d (MD5) Previous issue date: 1978 / Resumo: O presente trabalho visa â caracterização de sucos tropicais tipicamente brasileiros, no caso, caju e maracujá, através de um estudo das propriedades físicas, químicas e organolépticas. Os sucos dessas frutas, além da importância no consumo interno, pois são de baixo custo, poderiam trazer mais divisas ao País, com a exportação para diversas partes do mundo. O estudo foi dividido em 2 partes: (1) determinação da composição qualitativa e quantitativa de carotenóides e valor de vitamina A de sucos processados e não processados; e (2) comparação de sucos clarificados e não-clarificados através das propriedades sensoriais e das características físicas e químicas, comumente estudadas em sucos como sólidos solúveis, pH, acidez total, açúcares totais e redutores, ácido ascórbico e taninos, além do conteúdo de carotenóides. A identificação dos carotenóides foi feita através dos espectros de absorção, ordem de saída na coluna cromatográfica, valores de Rf em cromatografia em camada delgada e, em alguns casos, reações químicas específicas. A quantificação realizou-se por meio da absorção máxima, aplicando-se a lei de Beer. A composição qualitativa de carotenóides não variou entre os sucos processados e não-processados, tanto de caju como de maracujá. Nos sucos de caju foram identificados oito carotenóides: a-caroteno, ß-caroteno, ?-caroteno, cis-ß-caroteno, criptoxantina, aurocromo, criptocromo e auroxantina. ß-caroteno foi o pigmento mais abundante e chegou a cerca de 40% nos sucos processados e 50% no suco não-processado do lote de frutas maduras. Foram detectados onze carotenóides nos sucos de maracujá: a-caroteno, ß-caroteno, ?-caroteno, neurosporeno, ?-caroteno, licopeno, aurocromo, auroxantina, criptocromo, uma fração não identificada, e cantaxantina, este último um corante adicionado no suco comercial A. O maior pigmento foi o ?-caroteno com 55% do conteúdo total de carotenóides nos sucos processados e 36% no suco não-processado do lote de frutas não estocadas. A variação existiu realmente na composição quantitativa, pois os carotenóides diminuíram significativamente nos sucos processados. Além disso, houve diferença também entre os lotes dos sucos não-processados, pelos efeitos do grau de maturação, no caso do de caju e do tempo de estocagem das frutas utilizadas, no caso do de maracujá. A quantidade total de carotenóides foi bem maior no suco de maracujá do que no de caju, o que se esperava por causa da cor mais intensa no suco de maracujá. O valor de vitamina A no suco de maracujá também foi maior que para o de caju, mas não proporcionalmente ao total de carotenóides, uma vez que o pigmento encontrado em maior quantidade, no suco de maracujá, foi o ?-caroteno que não tem atividade vitamínica. Alem disso, como se esperava, o total de vitamina A foi menor nos sucos processados e nos sucos não-processados do lote de frutas verdes e estocadas do que no caso do suco não-processado do lote de frutas maduras e não estocadas. Na comparação entre sucos clarificados e não-clarificados, a diferença preponderante foi a perda total dos carotenóides, e conseqüentemente da vitamina A, que não ficam solúveis nos sucos clarificados. Quanto as determinações comumente aplicadas em sucos de frutas, os sólidos solúveis, ácido ascórbico e taninos, foram as propriedades mais afetadas pela remoção da polpa. Do ponto de vista organoléptico, o suco de caju teve diferenças altamente significativas para gosto e odor entre sucos com e sem polpa. A principal diferença no sabor foi a perda de adstringência no suco sem polpa. Já no suco de maracujá não houve diferença de gosto nem de odor entre os sucos clarificados e não-clarificados / Abstract: The present research involves the characterization of tropical, typically Brazilian fruit juices, particularly cashew-apple and passion-fruit, through a study of physical, chemical and organoleptic properties. Aside from their importance in domestic consumption on account of their low cost, these juices could be exported to other parts of the world, bringing in more revenue for the country. The study consisted of two parts: (1) determination of the qualitative and quantitative composition of the carotenoids and the vitamin A value of processed and unprocessed juices; and (2) comparison of clarified and unclarified juices according to sensory properties, physical and chemical characteristics commonly studied in juices, such as soluble solids, pH, total acidity, total and reducing sugars, ascorbic acid and tannins, in addition to the carotenoid content. The carotenoids were identified according to the visible absorption spectra, the order of elution from the chromatographic column, the Rf values in the thin layer plates and, in some cases, specific chemical reactions. The quantitative determination was accomplished by means of the maximum absorbance, applying the Beer's law. The qualitative composition of the carotenoids did not vary between processed and unprocessed juices in both the cashew-apple and passion-fruit. Eight carotenoids were identified in the cashew-apple juices: a-carotene, ß-carotene, ?-carotene, cis-ß-carotene, cryptoxanthin, aurochrome, cryptochrome and auroxanthin. ß-carotene was the predominant carotenoid comprising about 40% of the carotenoid content in the processed juices and 50% in the unprocessed juice obtained from ripe fruits. Eleven carotenoids were detected in passion-fruit juices: a-caroteno, ß-caroteno, ?-caroteno, neurosporeno, ?-caroteno, lycopeno, aurochrome, auroxanthin, cryptochrome, an unidentified fraction and canthaxanthin, the latter being a colorant added to commercial juice A. The major pigment was ?-carotene, consisting 55% of the total carotenoid content in the processed juices and 36% in the unprocessed juice obtained from freshly harvested fruits. Distinct variations were observed in the quantitative composition, since the carotenoids decreased significantly in the processed juices. Differences also existed between batches of the unprocessed juices, due to the stage of maturity in the case of cashew-apple and the storage time of the fruits utilized in the case of passion-fruit. The total carotenoid content of passion-fruit was much higher than that of cashew-apple, which was to be expected from the more intense color of the passion-fruit juice. The vitamin A value of the passion-fruit juice was also higher than that of cashew-apple, but the difference was not proportional to the total carotenoids content, since the principal pigment in passion-fruit juice was ?-carotene wich does not have any provitamin A activity Futhermore, the vitamin A value, as expected, was lower for processed juices and unprocessed juices obtained from batches of unripe and stored fruits, as compared with unprocessed juices taken from batches of ripe and fresh fruits. In comparing clarified and unclarified juices, the predominant difference was the total lose of carotenoids, and consequently vitamin A, which were insoluble in the clarified juices. Regarding the determinations which are usually applied to fruit juices, the soluble solids, ascorbic acid and tannins were most affected by the removal of the pulp. From the organoleptic evaluation of cashew-apple juice, highly significant differences in odor and taste existed between juices with and without pulp. The main difference in taste was the loss of astringency in the juice without pulp. In the passion-fruit juices, no difference was observed in taste and odor in clarified and unclarified juices / Mestrado / Ciência de Alimentos / Mestre em Ciência de Alimentos

Cryptophytes are free-living unicellular algae which are important for the productivity and food chain Dynamics of temperate lakes. This study provides fundamental information on the ecophysiology of two freshwater cryptophytes of different cell size, mainly in terms of growth and related factors. This thesis comprises of six chapters, three of which describe light or light-and-temperature experiments with small-scale batch cultures (Chapters. 2 to 4), one depicts a larger scale laboratory experiment simulating natural conditions (Chapter 5) and the two last (Chapters 6 and 7) are based on short-term investigations in situ. The effects of light and temperature on nutrient-saturated growth and cellular composition (chlorophyll a, proteins, carbohydrates) were studied in batch cultures. With the help of mathematical models, the physiological basis for interspecific differences of growth response was determined (Chapter 2). The cryptophyte strain L315 appeared to be a cold-water species as its optimum temperature was ca. 19°C. The strain L485 was more adapted to warm-water conditions with its optimum of ca. 24.5 °C. In respect of their growth response to irradiance, L485 can be said to be a stenotopic and L315 a eurytopic strain, as L485 shows photoinhibition soon after saturation point, whereas L315 tolerates a much wider range of irradiance. The role of changes in cellular composition is discussed. In order to explain the observed growth differences the effects of light and temperature on gross photosynthesis, respiration and hence net productivity were studied (Chapter 3). The observed respiration/photosynthesis ratios were high, as in L485 and L315 respiration accounted for 17-77 % and 14-81 % of gross photosynthesis, respectively. Under optimum conditions the respiration/Pmax for L485 was 17 % and for L315 58 %. The response of cryptophytes to chromatic light was studied by means of quantitative epifluorescence microscopy and it was found that in comparison to blue-green algae cryptophytes L485 and L315 do not gain such great adaptational advantages in terms of growth by chromatic adaptation (Chapter 4). The modest role of chromatic adaptation is discussed. The role of diel vertical migrations (DVM) in the growth of cryptophytes was studied in 4 m tall experimental columns (Chapter 5). Results revealed that by migrating into cooler, nutrient rich. hypolimnion flagellated cryptophytes can increase their growth rate under conditions where resources (light and nutrients) are spatially separated for prolonged time periods. This study also emphasizes the need for more detailed DVM studies in situ. Finally, the pattern and timing of nuclear and cellular division in two Cryptomonas species in situ was studied by means of mitotic index technique (Chapter 6) and DNA quantification (Chapter 7). The nuclear division of Cryptomonas L485 (Chapter 6) appeared to be well phased, but as in this division pattern mitosis and cytokinesis were totally overlapping, it was impossible to calculate in situ growth rates. Field observations (Chapter 7) revealed that DNA quantification by means of epifluorescence microscopy is possible from a natural cryptophyte population, but as the Cryptomonas sp. population under scrutiny was not well phased, growth rate calculation could not be carried out. The survival strategies of Cryptophytes L485 and L315 in terms of r vs. K strategies are discussed in Chapter 8. It is pointed out that, although the habitats occupied by these strains as well as some of their morphological and physiological features indicate that L485 is probably a r-strategist and L315 a K-strategist, it is not possible to draw final conclusions on the basis of this study. Light and temperature, i.e. the factors mostly studied in this thesis, are presumably not the environmental factors of greatest selective importance for these cryptophytes in natural competitive situations.

The technique of Raman spectroscopy was used in a study of shards of known (Ming and Meissen) and unknown (archaeological) origin. A tile shard from the Citadel of Algiers was included in this study as further confirmation of the consistency of the methods that are developed. The Citadel from which the tile shard was obtained was built in 1516 and represents a landmark from pre-colonial Algeria. The results were compared with those obtained from studies on intact museum pieces of known (Ming) origin. A consistent method of studying underglaze pigments on glazed ceramic artifacts by directing the laser beam through the predominantly silicate glaze was developed. The glaze depth profiling method developed proved to be very useful in the analysis and gives not only a detailed composition for the glaze/ceramic interfacial pigment, but also the order in which the various interfacial pigment layers were applied at the time of manufacture. The information acquired leads to an understanding of the level of technological development of the manufacturers. The detailed study and characterisation of the pigments that were analysed in this way gives insight into trade relations among ancient societies of the Mediterranean and will also assist archaeologists in establishing cut-off dates for the archaeological sites from which the artifacts were recovered. All the shards, except one from Meissen (Germany), were provided by the National Cultural History Museum of South Africa and the intact Ming dynasty plates were provided by the J.A. van Tilburg Museum of the University of Pretoria. The tile shard sample from the Citadel of Algiers was donated for the study. The results indicate that none of the archaeological shards could possibly be of Ming dynasty origin based on, firstly, the use of amorphous carbon to darken the cobalt blue (CoAl2O4) used as decoration on the shards, and secondly on the use of white (synthetic) anatase to whiten the ceramic surface before the application of the pigment since this synthetic anatase is known to have been manufactured for the first time around 1920. An ancient rediscovered ternary pigment (Pb2SnSbO6.5) previously found on Italian paintings of the 16th century, for example, “Lot and his daughters” by G.B. Langetti and “Entrance of Christ in Jerusalem” by Luca Giordano, was identified on the Citadel tile and successfully characterised. A Pb-O vibrational Raman band at 127 cm-1 for this pigment was assigned for the first time. Additional pigments identified on the tile include Naples yellow (Pb2Sb2O7), lead (II) stannate (Pb2SnO4), cobalt blue (CoAl2O4) and cassiterite (SnO2). The bulk of the tile body is composed mainly of hematite (á-Fe2O3), maghemite (ã-Fe2O3), magnetite (Fe3O4) and quartz (á-SiO2), with traces of calcite (CaCO3) and amorphous carbon. The unique non destructive depth profiling method that was developed in this study can now be applied to the study of underglaze pigments on intact porcelain artifacts in museums and private collections around the world for authentication purposes and for comparison with archaeological shard samples. / Thesis (PhD)--University of Pretoria, 2010. / Chemistry / unrestricted

No description available.

Carotenoid pigments in W. dermatitidis, the first pathogenic, dematiaceous fungus in which carotenoid pigments nave been reported, are located primarily (81%) in lipid organelles which floated on the surface of the supernatant fraction of lysed cells. Pigment in this fraction could be extracted with ethyl ether without prior treatment with acetone indicating the pigment is unbound in the lipid organelle. Eight percent remains after exhaustive ether extraction and is recovered after the sample is treated with acetone indicating this fraction is non-covalently bound to proteins in the membranes associated with the lipid organelle. The remaining pigment (about 12%) represents contamination of the supernatant with the lipid organelles.

Raman spectroscopy is a powerful tool for identification both inorganic and organic compounds including microbial biomolecules. Together with the fact, that it is considered to be the important nondestructive instrument for use on Mars within future robotic missions, it is necessary to assess its capabilities in scenarios relevant for both Martian and terrestrial conditions. In this work, the potential of Raman spectrometry was tested - including both bench-top laboratory systems as well as portable counterparts - to detect traces of life within evaporitic matrices through biomolecular identification. Due to their chemical and physical nature resulting in optical properties, pigments are important organic compounds in Raman spectroscopic analysis using visible excitation. Hence in this work we have focused on the Raman spectroscopic identification of pigments as biomarkers with relevance for investigation of life in both extreme terrestrial and potentially extraterrestrial environments. Results of methodical work are presented in Appendices I to III, dealing particularly with β-carotene as a model carotenoid pigment. The concentration limits of this biomarker in three different evaporitic matrices (halite, gypsum and epsomite) have been determined for artificially prepared powdered mixtures alone...

Philosophiae Doctor - PhD / The disposal of brine effluent from inland wastewater desalination plants is a growing global problem with adverse economic and environmental implications because of the substantial cost associated with its disposal and the potential for polluting groundwater resources. Currently, the best and most economical option for brine disposal from inland desalination plants is the use of evaporation ponds, which concentrate the liquid until getting a solid waste that can be valued or directly managed by an authorized company. The effectiveness of these ponds is therefore dependent on the evaporation rate, which has previously been improved by the addition of dyes such as methylene blue. However, the addition of chemical dyes to the evaporation ponds poses a threat to the environment, wildlife, and humans.