Thesis (MSc (Physics))--University of Stellenbosch, 2007. / Imaging and spectroscopy of laser induced chlorophyll fluorescence (LICF) are emerging as useful tools in plant physiology and agriculture since these methods allow an early detection of plant stress and transformation of plant tissue, before visual symptoms appear. Chlorophyll fluorescence is governed by photosynthetic efficiency and it depends on the plant species and physiological state. In addition, the laser induced fluorescence of chlorophyll molecules in the red and far red spectral range is also used to study basic processes and phenomena in photo-excited molecules. In the work reported here experimental setups used for laser induced chlorophyll fluorescence imaging and spectroscopy techniques were developed to investigate chlorophyll fluorescence under constant illumination and also to detect green-fluorescent protein (GFP) by looking at the chlorophyll fluorescence spectrum and image. He-Ne (wavelength 632 nm), tunable argon ion (wavelength 455 nm), and excimer (wavelength 308 nm) lasers were used as excitation sources. An Ocean Optics spectrometer was used to record the spectrum of the chlorophyll fluorescence and the variation of the chlorophyll fluorescence spectrum with time. The chlorophyll fluorescence spectrum of tobacco leaves expressing GFP was compared to that of control leaves. A charge-coupled device (CCD) camera was used to image the fluorescence from GFP expressing and control tobacco leaves to investigate the effect of GFP genes on chlorophyll fluorescence in relation to the state of the plant material. The spectral analysis technique and image processing procedures were elaborated in order to obtain better information on chlorophyll fluorescence. The results of this work show that the experimental setups and analytical procedures that were devised and used are suitable for laser induced chlorophyll fluorescence analysis. Fluorescence bleaching could be obtained from the time variation of the fluorescence spectrum, and plant expressing GFP can be distinguished from control plants by differences in the laser induced chlorophyll fluorescence.

Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Non-destructive portable X-ray Fluorescence (pXRF) and Particle Induced X-ray Emission (PIXE) were used to measure the elemental concentration of rock art fragment paintings. For pXRF the Amptek Silicon Drift Detector (SDD) and Niton XL3t spectrometers were used to perform the measurements. These two spectrometers use different spectrum analysis methods. The Peak Deconvolution (PD) analysis method is used for the Amptek SDD and an Inverse Overlap Matrix (IOM) method is used for the Niton XL3t spectrometer. The pXRF methods were validated by using alloys, coins and rock standards. The validation is important to establish if the pXRF technique is properly understood and used and to advance the investigation to more complex rock art paintings, with heterogeneous and layered properties. The elemental concentrations obtained for the Standard Reference Materials (SRMs), which were used for the validation, were in good agreement with that of the known concentration of the SRMs. The two rock art fragments which were analysed from the Mount Ayliff and Ha Khotso caves were part of larger rock art painting prior to it being naturally exfoliated from the rock. For the Mount Ayliff rock art, seven paint points, two unpainted rock (varnish) point adjacent to the paint and the back of the rock were analysed. The colour of the paint ranged from black, shades of brown and shades of red. The black paint is due to manganese or charcoal. The red colour is due to iron oxide and the red-brown colour is due to Hematite (a type of ferrous oxide) [1]. For the Ha Khotso fragment the paint on the front of the rock and the rock substrate (back of the rock) were analysed. For the Mount Ayliff rock art fragment the results for both pXRF spectrometers indicated that the elemental concentration was uniform across the fragment. This is due to the formation of a uniform layer of minerals such as silica and calcium introduced by the seepage of water through the cracks of the cave. Therefore no correlation could be established between the colour of the rock art paint and the elements detected, as was found with the work done by Peisach, Pineda and Jacobson [1]. For the Ha Khosto rock fragment a relation between the Ca composition and the cream colour of the rock art paint was established. Both the PIXE and pXRF techniques were used to identify the compound concentrations of the Ha Khotso rock art fragment. The comparison between the two techniques highlights the complexity of rock art paint analysis. The results from the PIXE elemental mapping indicated the non-uniform distribution of the elements in the analysed region. From the rock art fragment measuring the analysed points 5 times and obtaining the same results, indicated that the particle size and inhomogeneities did not have much effect on the compound compositions. In order to obtain high accuracy results with pXRF, sound scientific methodology with specific knowledge and expertise, not only about the XRF technique, but also about the sample under investigation is required. For alloy analysis pXRF is well suited, the analysis of geological material however more complex, since they are composed predominately of low atomic elements e.g. silicon, aluminium, magnesium, sodium, oxygen and carbon – all of which are excited with very low efficiencies. / AFRIKAANSE OPSOMMING: Nie-beskadigended X-straal Fluoresensie (pXRF) en Deeltjie Geinduseerde X-straal emmissie (PIXE) was gebruik om die elementêre konsentrasie van die rotstekeninge in hierdie studie te bepaal. Vir die pXRF-tegniek is die “Amptek Silicon Drift Detector (SDD)” en die “Thermo Scientific Niton XL3t” spektrometers gebruik gemaak om die metings uit te voer. Die twee spektrometers maak gebruik van verskillende spektrum analiseringsmetodes.Die “Peak Deconvolution (PD)” analiseringsmetode is gebruik vir die “Amptek SDD” en die “Inverse Overlap Matrix (IOM)” analiseringsmetode is gebruik vir die “Thermo Scientific Niton XL3t” spektrometer. Vir die validasie van die pXRF-metode is van allooie, muntstukke en rots standaarded gebruik gemaak. Die validasie is belangrik om vas te stel of die pXRF tegniek behoorlik verstaan en gebruik word en om die ondersoek te bevorder na meer komplekse rotstekeninge, met heterogene en lae eienskappe. Die element konsentrasies wat vir die “Standard Reference Material (SRM)” wat gebruik is vir die validasie, was in 'n goeie ooreenkoms met die van die konsentrasie van die SRM, wat bekend is. Die twee rotstekeninge wat ontleed is van die Mount Ayliff en Ha Khotso grotte en was deel van 'n groter rots kuns skildery voordat hul natuurlik afgebreek het. Vir die Mount Ayliff rotskuns, is sewe verf punte, twee ongeverfde rots (vernis) punte aangrensend aan die verf en die agterkant van die rots ontleed. Die kleur van die verf het gewissel van swart, skakerings van bruin en skakerings van rooi. Die swart verf kan toegeskryf word aan mangaan of houtskool. Die rooi kleur is as gevolg van ysteroksied en die rooi-bruin kleur is as gevolg van Hematiet ('n tipe van yster oksied) [1]. Vir die Ha Khotso rotskuns is die verf aan die voorkant van die rots en die rots substraat (agterkant van die rots) ontleed. Vir die Mount Ayliff rotstekening het die resultate vir beide pXRF spektrometers aangedui dat die elementele konsentrasie uniform oor die rotstekening is. Dit is as gevolg van die vorming van 'n uniforme lagie van silica en kalsium, wat deur die sypeling van water deur die krake van die grot na die oppervlak van die rotstekening beweeg het. Daarom kon geen korrelasie tussen die kleur van die rotstekening en die elemente wat gemeet is bepaal word nie, soos gevind deur die werk van Peisach, Pineda en Jacobson [1]. Vir die Ha Khotso rotstekening is ‘n verband tussen die room kleur van die rotstekening verf en Ca konsentrasie gevind. Beide die PIXE en pXRF tegnieke is gebruik om die konsentrasies van die Ha Khotso rotstekening te identifiseer. Die vergelyking tussen die twee tegnieke beklemtoon die kompleksiteit van rotstekening verf analise. Die resultate van die PIXE elementele karakterisering het aangedui die nie-eenvormige verspreiding van die elemente in die ontlede area. Deur die meting van die ontlede punte 5 keer te herhaal, en dieselfde resultate verkry, is ‘n aanduiding dat die deeltjie grootte en inhomogeniteite nie veel invloed op die elementele konsentrasies het nie. Ten einde 'n hoë akkuraatheid resultate te kry met pXRF, moet goeie wetenskaplike metode toegepas word met spesifieke kennis en kundigheid, nie net oor die XRF tegniek, maar ook oor die rotstekening wat ondersoek word vereis. pXRF is wel geskik vir die ontleding van allooie, die ontleding van geologiese materiaal is egter meer kompleks, aangesien die materiaal hoofsaaklik bestaan uit lae atoomgetal elemente bv silikon, aluminium, magnesium, natrium, suurstof en koolstof - wat almal met lae doeltreffentheid opgewek en baie afgerem word in die materiaal.

No description available.

The use of compressed CO2 processing to alter the pore size, structure and timescale of silica condensation in surfactant templated silica thin films and powders is investigated by systematically varying the template structure and CO2 processing conditions. Tailoring the mesoporous materials increases its potential applications, as demonstrated in catalysis, drug delivery, chromatographic and electrode applications. This work demonstrates for the first time the applicability of fluorinated surfactants as templates for the synthesis of mesoporous silica thin films by dip coating. Well-ordered films with 2D hexagonal close-packed pore structure are synthesized in an acid-catalyzed medium using three cationic fluorinated templates of varied tail length and branching (C6F13C2H4NC5H5Cl, C8F17C2H4NC5H5Cl and (CF3)2CFC5F9C2H4NC5H5Cl). CO2 processing of the fluorinated templated silica results in a significant and controlled increase in pore diameter relative to the unprocessed films. The pore expansion is significantly greater compared to the negligible expansion observed in hydrocarbon (C16H23NC5H5Br) templated silica. The greater swelling of the fluorinated templates is attributed to the favorable penetration of CO2 in the CO2-philic fluorinated tail and the relative solvation of each template is interpreted from their interfacial behavior at the CO2-water interface. The CO2 based pore expansion observed in fluorinated surfactant templated films is extended successfully to base-catalyzed silica powders templated with a fluorinated surfactant (C6F13C2H4NC5H5Cl). Pore expansion in silica powders is significantly less than in acid catalyzed films and demonstrates the effects of pH on surfactant selfassembly in CO2 and increased silica condensation at basic conditions, which inhibits pore expansion. Finally, the use of fluorescence probe molecules is demonstrated for in-situ monitoring of the of CO2 processing of surfactant templated silica films to provide time dependent data on the local environment and dynamics of CO2 penetration. CO2 uptake occurs in surfactant tails even for hydrocarbon templates (C16H23N(CH3)3Br and C16H23NC5H5Br), which display negligible CO2 based swelling of the resulting pores. The timescale of silica condensation increases significantly in the presence of CO2 suggesting opportunities for structure alteration through application of external forces, such as magnetic fields and change in substrate chemistry and system humidity

Master of Science / Department of Biological & Agricultural Engineering / Stacy L. Hutchinson / The shortage of clean, usable water is a global problem (Millennium Ecosystem Assessment, 2005). As much as 80% of the world’s population has been reported to be in areas of high water security risk due to a convergence of factors, such as watershed disturbance, pollution, water resource development and biotic factors (Voeroesmarty et al., 2010). Water reuse technologies are a potential solution to this problem. However, implementation of treatment technologies for improved water reuse require rapid, effective monitoring techniques capable of insuring treatment quality. Fluorescence spectroscopy has shown potential for wastewater treatment monitoring due to its sensitivity, selectivity, and capacity to be employed in-situ. Online fluorescence data and full fluorescence excitation-emission matrices coupled with parallel factor analysis (PARAFAC) were employed to evaluate the treatment performance of a membrane bioreactor (MBR) at Fort Riley, KS. Specific research goals were to evaluate the effectiveness of fluorescence for monitoring wastewater treatment and to determine the contamination detection limit of fluorescence techniques in a non-potable reuse scenario. Study results revealed a two-stage startup period, the first 60 days indicated membrane cake layer formation and the first 90 days showed signs of oxic tank maturation. Fluorescence was found to be effective at monitoring carbon concentration trends throughout the MBR system, showed preferential removal of protein-like dissolved organic matter (DOM), and an increase in biodegradation of DOM as the oxic tank matured. A ratio of the humic-like fluorescent components to the protein-like fluorescent components correlated to TOC removal (R² = .845, p < .001). Also, fluorescence was able to detect contamination in the effluent at the 0.74-1.24 mg C/L level using two wavelength pairs, indicating that effective real-time monitoring for contamination can be accomplished with minimal instrumentation and post-processing of data.

Afin de lever le mystère centenaire qui entoure l'origine du changement de volume associé au dépliement des protéines globulaires, nous avons constitué une collection de 10 mutants du variant hyperstable de la SNase, ∆+PHS. Chacune de ces mutations a été conçue pour créer une nouvelle cavité ou agrandir une cavité existante au sein de la protéine. Dans un premier temps, nous avons analysé comment l'environnement structural local conditionne l'adaptation à la mutation. Les expériences de fluorescence sous haute pression ont montré un accroissement systématique de la différence de volume entre les états replié et déplié pour les 10 variants par rapport à ∆+PHS. Ce résultat majeur, qui s'ajoute à une étude récente démontrant que les effets d'hydratation ne contribuent pas de manière significative au changement de volume, démontre sans ambiguïté que la différence de volume entre les états replié et déplié est principalement due à la présence de cavités internes dans la structure native des protéines. Les mesures par RMN des changements de volume ont permis d'établir une cartographie des effets de la pression à l'échelle du résidu et d'identifier les intermédiaires de repliement peuplant le paysage énergétique. En analysant les cinétiques de dépliement, nous avons finalement pu caractériser les conséquences de ces mutations sur les états de transitions de la SNase. / To solve the century-old question of the origin of the volume change upon unfolding for globular proteins, we built up a collection of 10 mutants of the hyperstable variant of SNase, ∆+PHS. Each of these mutations was designed to create a cavity or to enlarge a naturally occurring cavity in the protein core. We first analyzed how the local structural environment determines the adaptation to the mutation. The high-pressure fluorescence experiments showed a systematic increase of the volume difference between the folded and unfolded states for the 10 variants, compared to ∆+PHS. This major result, in addition to a recent study demonstrating that the hydration effects do not provide any significant contribution to the volume changes, clearly demonstrates that the volume difference between the folded and unfolded states is predominantly due to the presence of internal cavities in the native structure. NMR measurements of the volume change allowed a mapping of the pressure effects on a residue scale and the identification of the folding intermediates populating the free-energy landscape. By analyzing the unfolding kinetics, we finally characterized the consequences of these mutations on the transition state ensembles of SNase.

A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering, 2017 / The Merensky Reef vertical grade distribution is highly variable within Styldrift I Mine. The variable nature of the Merensky Reef mineralisation necessitates regular and timeous updating of the planned mining cut with sampling information so that the optimum can be applied during mining operations. The current geochemical assay analysis that is used for the analysis of platinum group elements (PGEs) has been proven to be accurate and precise however it is expensive with long turn-around times from the laboratory. Portable X-ray fluorescence (pXRF) technology has been tested as an alternative to measure the platinum group element content along the Merensky Reef. pXRF technology cannot accurately measure PGE content directly. Copper and nickel are detectable by the pXRF analyser and, like PGEs, copper and nickel mineralisation peaks along Merensky Reef horizon. Copper and nickel were therefore tested as potential pathfinder elements to target PGE mineralisation along the Merensky Unit. The testing of the pXRF analyser was undertaken by analysing the accuracy of the results it produces as well as determining if a regression between copper/nickel to PGE content is possible along the Merensky Unit. The pXRF did not produce results of adequate accuracy as a consistent significant bias was detected with pXRF results which were consistently lower than laboratory results. Calibration of the pXRF using site specific samples was not sufficient to overcome the bias. Regressions from copper/nickel to PGEs were tested for the Merensky Footwall which could be isolated as a single data population. Significant outliers exist that do not fit the regression analysis due to the inconsistent PGE modes of occurrence along the Merensky Unit. Application of the pXRF to the study area therefore does not meet the required conditions. An underground trial of the pXRF has indicated that peaks in pXRF copper and nickel results often, but not always, coincide with peaks in PGE mineralisation. The pXRF can therefore be used as a low confidence indicator of PGE mineralisation however the user must be aware of the limitations of the instrument. pXRF analysis cannot be used reliably therefore geochemical assay analysis remains the most reliable method to analyse PGE content at Styldrift I Mine. / XL2018

Modelos experimentais de câncer de próstata demonstraram níveis aumentados de protoporfirina IX (PpIX) no sangue e nas fezes de camundongos, fazendo com que a quantificação dessa molécula pudesse ser aventada para a identificação desse tipo de tumor. Nesse estudo do tipo caso-controle, a autofluorescência de porfirinas em fezes humanas foi analisada usando espectroscopia de fluorescência em pacientes com câncer de próstata e controles. Dados sociodemográficos, amostras sanguíneas para determinação dos níveis de PSA (antígeno prostático específico) e amostras de fezes para quantificação de porfirinas foram obtidas após consentimento dos pacientes. Recrutaram-se 18 pacientes em amostra calculada a partir dos estudos de referência. Realizou-se varredura para encontrar o melhor pico espectrofotométrico a partir de diversas diluições acetona/fezes. Primeiramente, 3 mililitros de acetona de grau analítico foram adicionados a 0,3 gramas de fezes e a mistura foi macerada e centrifugada a 4.000 rotações por minuto durante 15 minutos. O sobrenadante foi analisado espectroscopicamente. Os espectros de emissão a 550-750 nm foram obtidos excitando as amostras a 405 nm. Variáveis sociodemográficas foram analisadas e evidenciaram homogeneidade entre os grupos estudados. Um contraste significativo entre as amostras de indivíduos normais e oncológicos foi estabelecido na região espectral de 670-675 nm (p = 0,000127), o que corresponde a um aumento significativo de porfirinas fecais em pacientes com câncer. Não houve correlação estatisticamente significativa entre os níveis de PSA e as porfirinas fecais (R = -0,0221). Neste estudo preliminar realizado em seres humanos, os resultados mostram um método simples e não invasivo para avaliar as porfirinas fecais, que têm o potencial de funcionar como um biomarcador tumoral em pacientes com câncer de próstata. Essa abordagem poderia aumentar a sensibilidade e a especificidade do teste de PSA. / Experimental models of prostate cancer have demonstrated increased levels of protoporphyrin IX (PpIX) in the blood and faeces of mice. Hence, the quantification of these autofluorescent molecules could be hypothesized to be a potential marker for this type of tumour. In this case-control study, the autofluorescence of porphyrins in human faeces from patients with prostate cancer and control subjects was analysed using fluorescence spectroscopy. Socio-demographic data, blood samples for determination of PSA levels and faeces samples for quantification of porphyrins were obtained after consent of the patients. Eighteen patients were recruited in a sample calculated from the reference studies. Scanning was performed to determine the best spectrophotometric peak from various acetone/faecal dilutions. First, 3 mL of analytical-grade acetone was added to 0.3 g of faeces, and the mixture was macerated and centrifuged at 4000 rpm for 15 min. The supernatant was analysed spectroscopically. The emission spectra from 550 to 750 nm were obtained by exciting the samples at 405 nm. Socio-demographic variables were analyzed and showed homogeneity among the groups studied. A significant difference between the samples from control and cancer subjects was established in the spectral region of 670675 nm (p = 0.000127), which corresponds to a significant increase in faecal porphyrins in patients with cancer. There was no statistically significant correlation between PSA levels and faecal porphyrins (R = -0,0221). In this preliminary study conducted in humans, the results show a simple and non-invasive method to assess faecal porphyrins, which have the potential to function as a tumour biomarker in patients with prostate cancer. This approach has improved sensitivity and specificity over PSA testing.

A adição de corantes fluorescentes a adesivos odontológicos possibilita a investigação da distribuição espacial desses materiais na interface dente-restauração, utilizando-se a microscopia confocal de varredura a laser (MCVL). A literatura indica falta de padronização na aplicação de agentes fluorescentes com tal finalidade. Esse estudo sistematizou estratégias para a adição de rodamina B (RB) e fluoresceína sódica (FS) a um sistema adesivo convencional de três passos, Adper Scotchbond Multi-Purpose (MP), e um autocondicionante de dois passos, Clearfil SE Bond (SE), considerados padrão-ouro na Odontologia. Os objetivos principais foram (a) determinar a menor faixa de concentrações de RB e FS necessária para produzir imagens satisfatórias da interface dentina-adesivo e (b) avaliar o efeito da adição desses corantes sobre algumas propriedades das resinas. Os adesivos foram marcados com RB ou FS em concentrações decrescentes (0,5, 0,1, 0,02 e 0,004 mg/mL) por meio de um método de dispersão semidireto. O comportamento fotofísico/ fluorescente dos adesivos marcados foi investigado por espectroscopia de fotoluminescência e MCVL. Paralelamente, avaliaram-se os adesivos quanto ao grau de conversão (GC) e ao ângulo de contato (AC). Tanto os resultados de GC como os de AC foram submetidos à análise de variância com dois fatores (adesivo e tratamento) com = 0,05, seguida de teste post-hoc de Tukey. Os máximos comprimentos de onda de emissão e de excitação da RB e da FS foram influenciados pelo meio polimérico e pela concentração de corante de modo geral. A MCVL preliminar de amostras de adesivo polimerizado, realizada sob condições experimentais padronizadas, mostrou que o comportamento fluorescente da RB em MP e SE foi muito semelhante na mesma concentração de corante, mas o mesmo não pôde ser dito do comportamento da FS, que foi notavelmente inferior no adesivo autocondicionante, SE, na concentração mais alta. Em dentina, os adesivos preparados com RB nas concentrações-alvo de 0,1 e 0,02 mg/mL apresentaram fluorescência ótima; já aqueles preparados com 0,004 mg/mL produziram fraco sinal. Adesivos preparados com FS a 0,5 mg/mL apresentaram ótima fluorescência na interface de adesão, enquanto que concentração menor desse corante não produziu sinal suficiente. Padrões morfológicos aparentemente atípicos foram observados na interface de adesão, quando da associação do adesivo SE com o corante FS. A adição de RB e FS nas quatro concentrações indicadas aos adesivos MP e SE não afetou o GC nem o AC em comparação com os grupos de controle correspondentes. Em suma, a RB mostra-se um corante mais versátil que a FS na avaliação morfológica das interfaces dentina-MP e dentina-SE via MCVL. A menor faixa de concentrações de RB nos adesivos MP e SE, na qual é possível produzir imagens satisfatórias das interfaces, situa-se entre 0,10,02 mg/mL. Já o corante FS deve ser adicionado a esses adesivos a pelo menos 0,5 mg/mL para produzir níveis de fluorescência satisfatórios na interface de adesão. A não ocorrência de efeitos deletérios sobre a polimerização e a molhabilidade das resinas estabelece uma margem de segurança para a incorporação desses agentes fluorescentes (em concentração 0,5 mg/mL) nesses sistemas monoméricos. / The addition of fluorescent dyes to dental adhesives makes it possible to investigate the spatial distribution of such resin-based materials in the tooth-restoration interface, using confocal laser scanning microscopy (CLSM). Literature indicates a lack of standardization on the application of fluorescent agents for this purpose. This work presents strategies for adding rhodamine B (RB) and fluorescein sodium salt (FS) to a three-step etch-and-rinse adhesive system, Adper Scotchbond Multi-Purpose (MP), and a two-step self-etching one, Clearfil SE Bond (SE), both regarded as \"gold standard\" in restorative dentistry. The main objectives were (a) to determine the lowest range of RB and FS concentrations required to produce suitable images of the dentin-adhesive interface via CLSM and (b) to investigate potential effects of addition of these dyes on some resin properties. The adhesives were labeled with RB or FS at decreasing concentrations (0.5, 0.1, 0.02 and 0.004 mg/mL) by means of a semi-direct dispersion method. The photophysical/fluorescent behavior of the labeled resins was investigated by photoluminescence spectroscopy and by CLSM. The adhesives were also investigated with regards to the degree of conversion (DC) and contact angle (CA). A two-way ANOVA of adhesive and treatment was conducted on DC and CA separately, followed by Tukeys test. The maximum emission and excitation wavelengths of RB and FS were influenced by the host polymer and the dye concentration in general. The preliminary CLSM of cured adhesive samples, performed with standardized settings, showed that the fluorescent behavior of RB in MP and SE was very similar in the same dye concentration, unlike the behavior of FS, which was lower in the self-etching adhesive for the highest dye concentration. In dentin, the adhesives prepared with RB at the target concentrations of 0.1 and 0.02 mg/mL presented optimal fluorescence; those with 0.004 mg/mL produced poor signal. Adhesives prepared with FS at 0.5 mg/mL presented optimal fluorescence at the bonding interface, whereas lower concentrations of FS did not produce sufficient signal. Atypical morphological features were observed at the bonding interface, when adhesive SE was used with FS. The addition of RB and FS at the four decreasing concentrations to adhesives MP and SE did not affect DC or CA compared to the corresponding controls. In short, RB is more versatile than FS for the morphological characterization of dentin-MP and dentin-SE interfaces via MCVL. The lowest range of RB concentrations in adhesives MP and SE that can produce suitable images of the bonding interface lies between 0.10.02 mg/mL. The dye FS should be added to these adhesives at 0.5 mg/mL at least to produce satisfactory fluorescence levels at the bonding interface. Since negative effects on polymerization and wettability of the resins were not observed, the use of RB and FS (in concentration 0.5 mg/mL) together with MP and SE should be reliable in terms of resin properties.

Diabetes Mellitus (DM) é uma síndrome metabólica complexa, causada pela secreção diminuída ou ausente de insulina pelas células beta pancreáticas, levando a hiperglicemia. A hiperglicemia promove a glicação de proteínas e, conseqüentemente, o aparecimento de produtos finais da glicação avançada (AGEs). Atualmente, os pacientes diabéticos são monitorados pela determinação dos níveis de glicemia e hemoglobina glicada (HbA1c). As complicações geradas pela hiperglicemia podem ser divididas em micro e macrovasculares, representadas por retinopatias, nefropatias, neuropatias e doenças cardiovasculares. A albumina (HSA) é a proteína sérica mais abundante no organismo humano e está sujeita à glicação. A protoporfirina XI (PpIX) é a molécula precursora da síntese do heme, componente estrutural da hemoglobina. Ensaios in vitro e em animais indicaram que a hiperglicemia promove uma diminuição de sua concentração em eritrócitos. A espectroscopia de fluorescência é uma técnica bastante utilizada na área biomédica. A autofluorescência corresponde à fluorescência intrínseca presente em algumas moléculas, estando esta associada à estrutura das mesmas. O objetivo deste trabalho foi utilizar a técnica de espectroscopia de fluorescência para mensurar os níveis de autofluorescência da PpIX eritrocitária e AGE-HSA em pacientes diabéticos e indivíduos saudáveis e compará-los com os níveis de glicemia e HbA1c. Este estudo foi realizado com 151 indivíduos (58 controles e 93 diabéticos). Os dados epidemiológicos de pacientes e controles foram obtidos nos prontuários médicos. Para os indivíduos controle, os valores de glicemia foram adquiridos dos prontuários médicos e os níveis de Hb1Ac obtidos pela utilização de kits comerciais. A determinação da autofluorescência da PpIX foi realizada com excitação de 405 nm e emissão de 632 nm. Para a determinação do AGE-HSA foi realizada excitação de 370 nm e emissão de 455 nm. Aproximadamente 50% dos diabéticos apresentaram lesões micro ou macrovasculares decorrentes da hiperglicemia. Não foram observadas diferenças significativas nos valores de intensidade de emissão de PpIX entre os grupos estudados (P=0,89). Na análise do AGE-HSA observou-se diferenças significativas dos valores de intensidade de emissão entre os dois grupos, sendo este valor 1,45 vezes maior para o grupo de indivíduos diabéticos (P<0,0001). Os pacientes com complicações diabéticas apresentavam intensidade de emissão de fluorescência 1,19 vezes maior que os indivíduos sem complicações decorrentes da doença (P= 0,01), mesmo não havendo diferenças significativas nos valores de HbA1c entre os dois grupos. Concluímos que a espectroscopia de fluorescência foi uma técnica eficaz na identificação da autofluorescência da PpIX e do AGE-HSA. A PpIX não foi um biomarcador eficiente para o acompanhamento do DM. A determinação dos níveis de autofluorescência do AGE-HSA foi eficiente para a discriminação entre os grupos e para o monitoramento da progressão da doença, podendo ser mais eficiente que a dosagem de HbA1c. A espectroscopia de fluorescência é uma técnica simples, rápida e de baixo custo para o acompanhamento de indivíduos diabéticos. / Diabetes Mellitus (DM) comprises a complex metabolic syndrome, caused by reduced or absent secretion of insulin by pancreatic beta cells, leading to hyperglycemia. Hyperglycemia promotes glycation of proteins and, consequently, the appearance of advanced glycation end products (AGEs). Currently, diabetic patients are monitored by determining levels of glucose and glycated hemoglobin (HbA1c). The complications caused by hyperglycemia may be divided into micro and macrovascular complications, represented by retinopathy, nephropathy, neuropathy and cardiovascular disease. Albumin (HSA) is the most abundant serum protein in the human body and is subject to glycation. The Protoporphyrin IX (PpIX) is the precursor molecule of heme synthesis, structural component of hemoglobin. The in vitro and animals studies have indicated that hyperglycemia promotes a decrease in its concentration in erythrocytes. The fluorescence spectroscopy is a technique widely used in biomedical field. The autofluorescence corresponds to the intrinsic fluorescence present in some molecules, this being associated with the same structure. The aim of this study was to use fluorescence spectroscopy to measure levels of erythrocyte PpIX autofluorescence and AGE-HSA in diabetic and healthy subjects and compare them with levels of blood glucose and HbA1c. This study was conducted with 151 subjects (58 controls and 93 diabetics). Epidemiological data of patients and controls were obtained from medical records. For control subjects, blood glucose levels were obtained from medical records and levels of Hb1Ac obtained by using commercial kits. The determination of the PpIX autofluorescence was performed with excitation at 405 nm and emission at 632 nm. Determination of AGE-HSA was performed with excitation at 370 nm and emission at 455 nm. Approximately 50% of diabetic had micro and macrovascular lesions resulting from hyperglycemia. There were no significant differences in the PpIX emission intensity values between groups (P = 0.89). In the analysis of AGE-HSA was observed significant differences in the values of emission intensity between the two groups, and this value was 1.45-fold greater for the group of diabetic (P <0.0001). Patients with diabetic complications had fluorescence emission intensity of 1.19-fold higher than individuals without disease complications (P = 0.01), even with no significant differences in HbA1c values between the two groups. We conclude that fluorescence spectroscopy was an effective technique in the identification of the PpIX autofluorescence and AGE-HSA. The PpIX was not an effective biomarker for the monitoring of diabetes. The determination of AGE-HSA autofluorecência was efficient for the discrimination between groups and monitoring disease progression, may be more effective than HbA1c dosage. The fluorescence spectroscopy is a simple, fast and low cost for the monitoring of diabetic patients.