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Ebadati, Nasrollah D. "Characterization of the Pigment-Protein Complex in Corynebacterium Poinsettiae." Thesis, North Texas State University, 1986. https://digital.library.unt.edu/ark:/67531/metadc798269/.
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The purpose of this study was to completely characterize the protein moiety in the caroteno complex in C. poinsettae, determine if the distribution and level of protein in the pigment-protein complex in membranes of the wild type and in a colorless mutant could account for the differences in the stability of the membrane, and to determine if this protein is common to other pigmented and non-pigmented organisms. Also, electron microscopy of cell membranes of C. poinsettiae which had been exposed to gold-labelled antibody against the protein moitey of the pigment-protein complex, demonstrating that the protein is randomly distributed in the membranes of both wild type and colorless mutant.
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McDermott, Gerry. "Structural studies on an integral membrane light-harvesting complex." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337507.
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Kell, Adam. "Energy transfer and exciton dynamics in photosynthetic pigment–protein complexes." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32539.
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Doctor of PhilosophyChemistry
Ryszard J. Jankowiak
The structure-function relationships of natural pigment–protein complexes are of great interest, as the electronic properties of the pigments are tuned by the protein environment to achieve high quantum yields and photon utilization. Determination of electronic structure and exciton dynamics in protein complexes is complicated by static disorder and uncertainties in the properties of system-bath coupling. The latter is described by the phonon profile (or spectral density), whose shape can only be reliably measured experimentally for the lowest energy state. Low-temperature, laser-based spectroscopies are applied towards model pigment–protein complexes, i.e., the Fenna-Matthews-Olson (FMO) and water-soluble chlorophyll-binding (WSCP) complexes, in order to study system-bath coupling and energy transfer pathways. Site-selective techniques, e.g., hole burning (HB) and fluorescence line narrowing, are utilized to overcome static disorder and reveal details on homogeneous broadening. In addition, excitonic calculations with non-Markovian lineshapes provide information on electronic structure and exciton dynamics. A new lognormal functional form of the spectral density is recommended which appropriately defines electron-phonon parameters, i.e., Huang-Rhys factor and reorganization energy. Absorbance and fluorescence spectral shifts and HB spectra reveal that samples of FMO may contain a subpopulation of destabilized proteins with modified HB efficiencies. Simulations of spectra corresponding to intact proteins indicate that the entire trimer has to be taken into account in order to properly describe fluorescence and HB spectra. The redshifted fluorescence spectrum of WSCP is described by uncorrelated energy transfer as opposed to previous models of excited state protein relaxation. Also, based on nonconservative HB spectra measured for WSCP, a mechanism of electron transfer between chlorophylls and aromatic amino acids is proposed.
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Georgiannakis, A. "The interplay between retinal pigment epithelial cells and the C5b-9 complex." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1460725/.
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In age-related macular disease (AMD) accumulation of complement proteins in the sub-retinal space is believed to contribute to either the malfunction or apoptosis of retinal pigment epithelial (RPE) cells and ultimately the death of the associated photoreceptors. Here, the effects of basal formation of the terminal membrane attack complex, C5b-9, were examined using primary porcine RPE (pRPE) cells. Immunohistochemical analysis showed that C5b-9 complex formation appeared to stabilise at 4 h on the basal surface of pRPE cells, after which it steadily decreased and was eliminated from the cell surface by 48 h. Within 1 h of C5b-9 formation there was a significant increase in trans-epithelial resistance (TER) when compared to untreated cells. Treatment with dynasore, an endocytosis inhibitor, suggested that pRPE cells may endocytose the C5b-9 complex, as this chemical reagent blocked the removal of C5b-9 from the cell surface. Surprisingly, treatment of pRPE cells with dynasore inhibited the C5b-9-mediated increase in TER. C5b-9 did not appear to have an effect on the expression of either the negative complement regulators CD59 and DAF, or the expression of the junctional protein ZO-1. However, immunofluorescence analysis demonstrated strong junctional staining for claudin-19 in C5b-9-treated pRPE cells when compared to control conditions. Also, the prolonged presence of C5b-9 appeared to reduce both mitochondria numbers and the localisation of Tim23, a trans-membrane mitochondrial channel. We also observed that basal assembly of C5b-9 slowed the binding of photoreceptor outer segments (POS) to the apical surface of pRPE cells. However, POS internalisation and the activation levels of MerTK, FAK and Src were not affected by the presence of C5b-9. In conclusion, work in this thesis demonstrated that C5b-9 rapidly forms on the basal surface of pRPE cells, and that in doing so it modulates a number of RPE cell properties. RPE cells survive C5b-9 attack by endocytosing the complex, but when this process is blocked they exhibit signs of cellular stress. These studies provide mechanistic insight into some of the chronic cytotoxic effects of C5b-9 that could ultimately drive RPE cell loss and dysfunction in AMD.
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Yang, Yiqun. "Integration of photosynthetic pigment-protein complexes in dye sensitized solar cells towards plasmonic-enhanced biophotovoltaics." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32857.
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Doctor of PhilosophyDepartment of Chemistry
Jun Li
Solar energy as a sustainable resource is a promising alternative to fossil fuels to solve the tremendous global energy crisis. Development of three generation of solar cells has promoted the best sunlight to electricity conversion efficiency above 40%. However, the most efficient solar cells rely on expensive nonsustainable raw materials in device fabrication. There is a trend to develop cost-effective biophotovoltaics that combines natural photosynthetic systems into artificial energy conversion devices such as dye sensitized solar cells (DSSCs). In this research, a model system employs natural extract light-harvesting complex II (LHCII) as a light-absorbing sensitizer to interface with semiconductive TiO₂ and plasmonic nanoparticles in DSSCs. The goal of this research is to understand the fundamental photon capture, energy transfer and charge separation processes of photosynthetic pigment-protein complexes along with improving biophotovoltaic performance based on this model system through tailoring engineering of TiO₂ nanostructures, attaching of the complexes, and incorporating plasmonic enhancement. The first study reports a novel approach to linking the spectroscopic properties of nanostructured LHCII with the photovoltaic performance of LHCII-sensitized solar cells (LSSCs). The aggregation allowed reorganization between individual trimers which dramatically increased the photocurrent, correlating well with the formation of charge-transfer (CT) states observed by absorption and fluorescence spectroscopy. The assembled solar cells demonstrated remarkable stability in both aqueous buffer and acetonitrile electrolytes over 30 days after LHCII being electrostatically immobilized on amine-functionalized TiO₂ surface. The motivation of the second study is to get insights into the plasmonic effects on the nature of energy/charge transfer processes at the interface of photosynthetic protein complexes and artificial photovoltaic materials. Three types of core-shell (metal@TiO₂) plasmonic nanoparticles (PNPs) were conjugated with LHCII trimers to form hybrid systems and incorporated into a DSSC platform built on a unique open three-dimensional (3D) photoanode consisting of TiO₂ nanotrees. Enhanced photon harvesting capability, more efficient energy transfer and charge separation at the LHCII/TiO₂ interface were confirmed in the LHCII-PNP hybrids, as revealed by spectroscopic and photovoltaic measurements, demonstrating that interfacing photosynthesis systems with specific artificial materials is a promising approach for high-performance biosolar cells. Furthermore, the final study reveals the mechanism of hot electron injection by employing a mesoporous core-shell (Au@TiO₂) network as a bridge material on a micro-gap electrode to conduct electricity under illumination and comparing the photoconductance to the photovolatic properties of the same material as photoanodes in DSSCs. Based on the correlation of the enhancements in photoconductance and photovoltaics, the contribution of hot electrons was deconvoluted from the plasmonic near-field effects.
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Amore, Diogo de Jesus. "Re-parameterisation of a three-band semi-empirical algorithm for c-phycocyanin-pigment estimation in an optically complex tropical reservoir." Instituto Nacional de Pesquisas Espaciais (INPE), 2016. http://urlib.net/sid.inpe.br/mtc-m21b/2016/02.05.11.51.
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The eutrophication of aquatic systems is a worldwide environmental problem. A major aftermath is health-inflicting toxic algal bloom, which can affect humans. Therefore, aquatic systems, mostly near urban environments require environmental monitoring. The use of remote sensing for monitoring algal blooms via bio-optical modelling is based on the spectral behaviour of the optically active components (OACs) in the water to estimate their concentrations. The detection of cyanobacteria, one of the main phyla of harmful algae, takes place via the identification of a unique pigment in inland waters cyanobacteria, the phycocyanin (PC). Remote sensing techniques, such as semi-empirical algorithms - a sort of bio-optical model - have been used to estimate PC concentration in aquatic systems using in situ hyperspectral data and satellite multispectral data. However, there is a lack in scientific works tackling PC prediction in tropical inland waters bearing PC in low concentration such as in city-supplying Guarapiranga reservoir at the southwestern region of São Paulo city. This is mostly true because scientific studies attempt to generate models based on bloom events. However, much uncertainty is associated with models results at the low concentration ranges. Therefore the goal of this research was to evaluate the re-parameterization of a semi-empirical algorithm for a tropical oligo-mesotrophic inland water. Radiometric, fluorometric, limnological, and multi-parameter sonde data were collected in Guarapiranga Reservoir, located. This thesis presents the findings which led to the algorithm re-parameterisation. Results showed that the calibration dataset (n=15) improved PC prediction R$^{2}$ by 15.3\% after the re-parameterisation; and for the validation dataset (n=19), PC prediction R$^{2}$ was improved by 4.79\%. NRMSE for the calibration dataset was bettered by 1.76\%; and it was almost equalised for the validation dataset (differed by 0.19\%). The new re-parameterisation correlation coefficient developed in this study presented a better R$^{2}$ (68\%) than that of the original algorithm (46\%). These correlations linked the band ratios used as enhancing coefficients to known PC spectral features. The bio-optical, radiometric, and water quality characterisation of Guarapiranga reservoir, and the evaluation of signal processing techniques of radiometric data yielded results that supported the generation of the new re-parameterisation coefficient. Such results were related to features in the blue-to-green spectral region capable of improving PC prediction. Uncertainties in the estimations are mainly due to the lack of in situ data. The re-parameterization was also considered for a synthetic dataset of the Ocean \& Land Colour Imager (OLCI) sensor/Sentinel 3. The simulation of OLCI data was conducted using its spectral response function, and it was important because of its potential use in environmental monitoring. Overall results were encouraging, however, further studies are suggested to further validate this new algorithm. Nevertheless, the development of a semi-empirical algorithm for low-concentration PC prediction in tropical inland waters is an important step for the development of an ever-improving robust tool for water quality monitoring.A eutrofização de sistemas aquáticos é um problema ambiental global. Uma consequência de alta importância disso é a floração de algas tóxicas a qual pode afetar os seres humanos. Portanto, sistemas aquáticos, principalmente aqueles próximos a centros urbanos requerem monitoramento ambiental. A utilização de sensoriamento remoto para o monitoramento de florações de algas através da modelagem bio-óptica é baseada no comportamento espectral dos componentes opticamente ativos (OACs) da água, de modo a estimar suas concentrações. A detecção de cianobactérias, um dos filos mais importantes dentre as algas tóxicas, ocorre através da identificação de um pigmento nestes micro-organismos de águas interiores denominado, ficocianina (PC). Técnicas de sensoriamento remoto, tais como algoritmos semiempíricos - um tipo de modelo bio-óptico - tem sido utilizado para estimar concentrações de PC em sistemas aquáticos utilizando dados hiperespectrais in situ e dados de satélite multiespectrais. Entretanto, há uma deficiência em trabalhos científicos abordando predição de PC em águas interiores tropicais com baixas concentrações de PC tais como o reservatório de Guarapiranga, no sudoeste da capital de São Paulo. Isto é uma realidade, pois estudos científicos tendem a gerar modelos baseados em eventos de florações em que há maiores concentrações de PC. Porém, muita incerteza está associada a resultados de modelos em baixas concentrações de PC. Portanto, o objetivo deste trabalho foi avaliar a reparametrização de um algoritmo semiempírico para uma água interior oligo-mesotrófica tropical. Dados radiométricos, fluorométricos, limnológicos, e de uma sonda multiparâmetro foram coletados no reservatório de Guarapiranga. Esta dissertação apresenta os resultados que levaram à reparametrização do algoritmo. Os resultados mostraram que o R$^{2}$ do conjunto de dados de calibração (n=15) melhorou a predição de PC em 15.3\% após a reparametrização; e o R$^{2}$ do conjunto de dados de validação (n=19), melhorou a predição em 4.79\%. O NRMSE para o conjunto de dados de calibração foi melhorado em 1.76\%; e os NRMSEs da validação praticamente estabilizaram (diferenciando-se em 0.19\%). O coeficiente de correlação desenvolvido para a nova reparametrização neste estudo apresentou um R$^{2}$ (68\%) melhor do que o coeficiente do algoritmo original (R2 = 46\%) com o qual foi comparado. Estas correlações associam razões de bandas, utilizadas como coeficientes de melhoramento, a características espectrais de PC já conhecidas. A caracterização bio-óptica, radiométrica, e de qualidade da água do reservatório, bem como a avaliação de técnicas de processamento de sinais dos dados radiométricos geraram resultados que apoiaram a geração do coeficiente de reparametrização. Tais resultados estiveram relacionados a características nas regiões espectrais do azul-verde como sendo capazes de melhorar a predição de PC. Incertezas nas estimações são essencialmente devidas à falta de dados in situ. A reparametrização também foi considerada para um conjunto de dados sintético do sensor Ocean \& Land Colour Imager (OLCI)/Sentinel3. A simulação dos dados do OLCI foi realizada utilizando a sua função de respota espectral, e foi importante por causa do seu uso potencial em monitoramento ambiental. De maneira geral os resultados foram encorajadores, entretanto, estudos futuros são sugeridos para uma validação mais robusta deste novo algoritmo. Contudo, o desenvolvimento de um algoritmo semiempírico para a predição de PC em baixas concentrações em águas interiores tropicais é um passo importante para o desenvolvimento de um monitoramento de qualidade da água passível de ser melhorado continuamente.
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Liversidge, Janet. "Immunoregulatory mechanisms in experimental autoimmune uveitis : the role of major histocompatibility complex products, retinal pigment epithelial cells and mononuclear leucocytes." Thesis, University of Aberdeen, 1989. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU482352.
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In this study a possible role for RPE cells as local antigen presenting cells in immune inflammatory eye disease was investigated. In contrast to observations in the rat model of EAU however, Class II positive RPE cells were never observed in vivo in the guinea pig model of EAU but responses of RPE cells in vitro implied that these cells may have an immunoregulatory role in retinal autoimmunity. The T cell mediated nature of EAU was studied in the guinea pig model. The phenotype of inflammatory cells present in developing lesions was examined. Earliest choroidal infiltrates appeared to be Th cells, but in established choroidal foci of inflammatory cells and in early retinal lesions, where rod outer segment (ROS) lysis was occurring, the presence of a Pan T-ve, Tc/s+ve population of putative effector cells was identified. In endstage lesions B cells became the predominant cell type, and may act as suppressor cells in this species. Infiltrating inflammatory cells and capillary endothelial cells expressed Class I and Class II antigens but RPE and Muller cells did not. Cyclosporin A (CsA) therapy prevented vitreal inflammation and there was a marked reduction of Class II antigen expression despite choroidal infiltrates of Tc/s. Delayed type hypersensitivity (DTH) skin reactions to retinal antigen were also profoundly suppressed by CsA.
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Slowik, Daria Marta [Verfasser], and Wolfram [Akademischer Betreuer] Saenger. "Structural and Functional Investigations on the Photosystem II core subunit PsbO and the antenna pigment-protein complex CP29 / Daria Marta Slowik. Betreuer: Wolfram Saenger." Berlin : Universitätsbibliothek der Technischen Universität Berlin, 2012. http://d-nb.info/1024771938/34.
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Lehmann, Rainer Patrick. "Studies on the structure and function of the bacteriochlorophyll C antenna complex of the chlorosomes from the phototrophic bacterium Chloroflexus aurantiacus : the pigment-binding function of the 5.7 kDa polypeptide /." [S.l.] : [s.n.], 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10687.
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Robert, Bruno. "Etude de la structure et des interactions au sein des complexes proteine pigments impliques dans la photosynthese bacterienne : contribution de la spectrometrie raman de resonance." Paris 6, 1987. http://www.theses.fr/1987PA066603.
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Pieper, Jörg. "Anwendung der hochauflösenden Laserspektroskopie zur Untersuchung der Energieniveaustruktur und der Elektron - Phonon - Wechselwirkung im lichtsammelnden Komplex II grüner Pflanzen." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2000. http://dx.doi.org/10.18452/14547.
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Hole-Burning (HB) und Fluorescence Line-Narrowing (FLN) bei 4.2 K sowie Experimente zur Temperaturabhängigkeit werden angewendet, um Energieniveaustruktur und Elektron-Phonon- Wechselwirkung im Antennenkomplex LHC II grüner Pflanzen zu untersuchen. Besondere Aufmerksamkeit gilt dabei der Vermeidung systematischer Meßfehler durch Reabsorption von Fluoreszenz oder durch Lichtstreuung und unerwünschtes Lochbrennen bei FLN-Experimenten. Durch die Auswertung von Lochspektren können erstmals drei niederenergetische elektronische Zustände bei 677.1, 678.4 und 679.8 nm nachgewiesen werden. Die inhomogene Breite der zugehörigen Absorptionsbanden beträgt etwa 4 nm. Wahrscheinlich stellt jeder dieser Zustände das tiefste Energieniveau einer Untereinheit des LHC II-Trimers dar und ist weitgehend an jeweils einem Chl a-Molekül lokalisiert. Die energetische Differenz zwischen den drei Zuständen kann durch strukturelle Heterogenität erklärt werden. Es kann nachgewiesen werden, daß die Meßergebnisse praktisch frei von Effekten durch unerwünschte Aggregation sind. Die homogene Linienbreite des energetisch tiefsten Zustandes bei 4.7 K wird vorwiegend durch phasenzerstörende Prozesse (pure dephasing) bestimmt. Die Lochbreiten innerhalb der 650 nm Absorptionsbande entsprechen Chl b-Chl a Energietransferzeiten von 1 ps und etwa 240 fs bei 4.2 K, während Lochbreiten innerhalb der 676 nm Absorptionsbande Chl a-Chl a Energietransferzeiten in der Größenordnung von 6-10 ps ergeben. In einer theoretischen Betrachtung werden die Beiträge zu Phonon-Seitenbanden bei HB und FLN separat analysiert. Auf dieser Grundlage können Ergebnisse von HB und FLN Experimenten an LHC II erstmals in einem konsistenten Modell durch schwache Elektron-Phonon-Wechselwirkung mit einem Huang-Rhys-Faktor von 0.9 und ein breites, stark asymmetrisches Ein-Phonon-Profil erklärt werden.Spectral hole-burning (HB) is combined with fluorescence line-narrowing (FLN) experiments at 4.2 K and studies of temperature-dependent fluorescence spectra in order to investigate low-energy level structure as well as electron-phonon coupling of the LHC II antenna complex of green plants. Special attention has been paid to eliminate effects owing to reabsorption of fluorescence and to assure that the FLN spectra are virtually unaffected by hole-burning or scattering artifacts. For the first time, analysis of the 4.2 K hole spectra reveals three low-energy electronic states at 677.1, 678.4 and 679.8 nm, respectively. The inhomogeneous width of their absorption bands is approximately 4 nm. It is likely that each of these states is associated with the lowest energy state of one trimer subunit with the energetic separations being due to structural heterogeneity. It is likely that each of the low-energy states is highly localized on a single Chl a molecule of the corresponding trimer subunit. The results are shown to be virtually free from aggregation effects. The homogeneous width for the lowest state at 4.7 K is predominantly due to pure dephasing. Widths of holes burned into the 650 nm absorption band correspond to Chl b-Chl a energy transfer times of 1 ps and about 240 fs at 4.2 K while holewidths for the 676 nm absorption band lead to Chl a-Chl a energy transfer times in the 6-10 ps range. The complexities associated with the interpretation of the phonon structure in HB and FLN spectra are discussed by theoretically analyzing the different phonon sideband contributions. On this basis, 4.2 K HB and FLN data can be consistently interpreted for the first time by weak electron-phonon coupling with a Huang-Rhys factor of about 0.9 to protein phonons with a broad and strongly asymmetric one- phonon profile.
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Joshua, Sarah. "Mobility of pigment-protein complexes in cyanobacteria." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1444430/.
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Phycobilisomes, the light harvesting complexes of cyanobacteria are highly mobile, fluorescent complexes known to diffuse freely on the thylakoid membranes, interacting with the reaction centre complexes to mediate efficient photosynthesis. The primary aim of this project is to establish what processes require this rapid movement of the complexes using a number of genetic, biochemical and microscopic techniques. The cyanobacterial species used extensively in the work presented in this thesis are the fully sequenced, naturally transformable Synechocystis sp. PCC 6803 and Synechococcus sp. PCC 7942. The latter lends itself particularly well to quantitatively elucidating the diffusion rate of fluorescent complexes, but qualitative detection of mobile fluorescent complex is also feasible with Synechocystis 6803. State transitions are observed in cyanobacteria upon the alteration of illumination conditions. A rapid redistribution of excitation energy between the reaction centres is observed. This was investigated using high osmotic strength buffers to fix phycobilisomes to reaction centres they were associating with upon their addition, thus inhibiting their mobility, as adjudged by spectroscopy and microscopy using the Fluorescence Recovery after Photobleaching (FRAP) technique. It was found that mobile phycobilisomes are required for cells to be capable of state transitions. Non-Photochemical Quenching (NPQ) is a protective mechanism seen in iron- deprived cyanobacteria. Extensively studied in plants, its supposed function is to dissipate excess energy as heat to prevent photodamage to the reaction centres. Using Synechocystis 6803 and the techniques described above, phycobilisome mobility was determined to be critical to NPQ induction, and the interaction with IsiA in cyanobacteria was proposed as being involved in the process. A previously inactivated gene thought to be involved in state transitions, rpaC, was over-expressed in Synechocystis 6803 and knocked out in Synechococcus 7942 and gave pleiotropic effects. The conclusion that the binding of phycobilisomes to PSII is predictably stronger than to PSI was exploited by comparing the strength of the binding in the Synechococcus 7942 mutant with the wild type. Data were suggestive of the protein being involved in phycobilisome to PSII binding. Psb28* mutants of both species used in this thesis were extensively characterised, as the cells also presented a highly unusual mobile PSII phenotype. Psb28 is possibly involved in maintaining thylakoid membrane organisation.
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Hofmann, Clemens. "Pigment pigment interactions and protein dynamics in light harvesting complexes a single molecule study /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971750483.
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Schmitt, Franz-Josef [Verfasser], and Hans Joachim [Akademischer Betreuer] Eichler. "Picobiophotonics for the investigation of pigment-pigment and pigment-protein interactions in photosynthetic complexes / Franz-Josef Schmitt. Betreuer: Hans Joachim Eichler." Berlin : Universitätsbibliothek der Technischen Universität Berlin, 2011. http://d-nb.info/1014971691/34.
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Medeiros, Patricia Neves de. "S?ntese de pigmento cer?mico ferrita de cobalto utilizando planejamento experimental." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12809.
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Synthetic inorganic pigments are the most widely used in ceramic applications because they have excellent chemical and thermal stability and also, in general, a lower toxicity to man and to the environment. In the present work, the ceramic black pigment CoFe2O4 was synthesized by the polymerization Complex method (MPC) in order to form a material with good chemical homogeneity. Aiming to optimize the process of getting the pigment through the MPC was used a fractional factorial design 2(5-2), with resolution III. The factors studied in mathematical models were: citric acid concentration, the pyrolysis time, temperature, time and rate of calcination. The response surfaces using the software statistica 7.0. The powders were characterized by thermal analysis (TG/DSC), x-ray diffraction (XRD), scanning electron microscopy (SEM) and spectroscopy in the UV-visible. Based on the results, there was the formation of phase cobalt ferrite (CoFe2O4) with spinel structure. The color of the pigments obtained showed dark shades, from black to gray. The model chosen was appropriate since proved to be adjusted and predictive. Planning also showed that all factors were significant, with a confidence level of 95%
Os pigmentos inorg?nicos sint?ticos s?o os mais utilizados em aplica??es cer?micas por apresentarem uma excelente estabilidade qu?mica e t?rmica e tamb?m, em geral, uma menor toxicidade para o homem e para o meio ambiente. No presente trabalho, o pigmento cer?mico preto CoFe2O4 foi sintetizado pelo M?todo de Polimeriza??o de Complexos (MPC) visando a forma??o de um material com boa homogeneidade qu?mica. Com o objetivo de otimizar o processo de obten??o do pigmento atrav?s do MPC foi utilizado um planejamento fatorial fracionado 2(5-2), com resolu??o III. Os fatores estudados na modelagem matem?tica foram: concentra??o de ?cido c?trico, tempo de pir?lise, temperatura, tempo e taxa de calcina??o. As superf?cies de resposta utilizando o programa statistica 7.0. Os p?s obtidos foram caracterizados atrav?s de an?lises t?rmicas (TG/DSC), difra??o de raios-x (DRX), microscopia eletr?nica de varredura (MEV) e espectroscopia na regi?o do UV-vis?vel. Com base nos resultados, foi verificada a forma??o da fase ferrita de cobalto (CoFe2O4) com estrutura espin?lio. A cor dos pigmentos obtidos apresentou tonalidades escuras, do preto ao cinza. O modelo escolhido foi adequado, visto que mostrou-se ajustado e preditivo. O planejamento tamb?m mostrou que todos os fatores foram significativos, com n?vel de confian?a em 95%
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Nieder, Jana Berit [Verfasser]. "Single-molecule spectroscopy on pigment-protein complexes / Jana Berit Nieder." Berlin : Freie Universität Berlin, 2011. http://d-nb.info/102593881X/34.
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Thompson, Russell Martin. "Nitrosylmetalloporphyrin complexes as models for cured meat pigments." Thesis, University of Surrey, 1988. http://epubs.surrey.ac.uk/848117/.
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A range of nitrosylmetalloporphyrin complexes, M(porph)NO [M = Fe, Co; porph = TPP, OEP, T[PIV]PP], some labelled with [15]NO, has been synthesised and investigated as structural and spectroscopic models of the cured meat pigment, nitrosylmyoglobin. The nitrosylmetalloporphyrins were found to be unstable in solution (and some in the solid state) with respect to loss or further reaction of the nitrosyl ligand. The diamagnetic cobalt (III) porphyrin nitrosyIs and a range of other square pyramidal complexes of cobalt(III) with an apical nitrosyl ligand have been further investigated by [15]N and [59]Co NMR spectroscopy to establish whether the CoNO group is bent or linear and to study nephelauxetic and spectrochemical effects at the metal. In all cases studied the CoNO group is bent (CoNO ~ 120°). The basal ligands were dithiocarbamate, tetradentate Schiff base, porphyrin, and bidentate diamine and oximate giving S[4], S[2]N[2], N[4], OONN, or ONON coordination in the equatorial plane. The shielding of both cobalt and nitrogen tends to decrease with decrease in M(d) to pi* (NO) back-bonding as indicated by M-N and N-O bond distances, and the MNO angle and the NO stretching frequencies. The shieldings decrease with electron withdrawal by ring substituents and also in going from sulphur to nitrogen to oxygen coligands, i.e. with decrease in ligand field splitting and in the nephelauxetism of the coligands. The bent nitrosyls of cobalt can function as oxygen transfer catalysts via a nitrosyl-nitro couple. Consequently, a range of Co(III) porphyrin nitro complexes, (L)Co(porph)NO[2] (porph = TPP, OEP; L = py, 1Melm) and several nitro complexes containing the other basal ligands have been synthesised and investigated by the [15]N and [59]Co NMR technique. The coordinated nitro ligand is labile and linkage isomerism and ligand exchange have been observed. These observations may be related to the deterioration of cured meat colour which is of importance to the food industry. The crystal structure of (py)Co(TPP)NO[2] is presented; the nitro group of which is rotationally disordered. Recrystallisation of (1MeIm)Co-(TPP)NO[2] gave [Co(TPP)(1Melm)[2]]NO[2], the crystal structure of which has been determined. Formation of this nitrite is further evidence for the lability of the nitro ligand. The known complex Fe(salphen)NO was prepared using ascorbic acid for the first time to prevent contamination with the oxo-bridged iron(III) dimer. Variable temperature [57]Fe Mossbauer effect studies of the S = 1/2 to S = 3/2 spin transition for Fe(salphen)NO show that the crossover is continuous and centred at T[c] ~ 181 K, and that the electronic transition between the two spin states is rapid on the Mossbauer timescale. The fluxionality of CoCl[2]([15]NO)(PPh[2]Me)[2] was studied by variable temperature [15]N and [31]P NMR. An [17]O NMR study of the ?-peroxo complex [(NH[3])[5]Co[17]O[2]Co(NH[3])[5]](NO[3])[4]. 2H[2]O is presented. An attempt to measure [15]N NMR spectra of the diamagnetic 18 electron species, Fe(porph)([14]NO)([15]NO) (porph = TPP, OEP) presumably containing linear FeNO[+] and bent FeNO[-] was unsuccessful.
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Adolphs, Julia [Verfasser]. "Theory of Excitation Energy Transfer in Pigment-Protein Complexes / Julian Adolphs." Berlin : Freie Universität Berlin, 2008. http://d-nb.info/1022719130/34.
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Gall, Andrew. "Purification, characterisation and crystallisation from a range of rhodospirillineae pigment-protein complexes." Thesis, University of Glasgow, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322488.
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Houlné, Guy. "Structure et expression des genes codant pour les apoproteines des antennes collectrices de photons ps2 et ps1 chez euglena gracilis." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13169.
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Caron, Lise. "Organisation des complexes protéines-pigments dans les thylakoides d'algues brunes." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37612426v.
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Caron, Lise. "Organisation des complexes proteines-pigments dans les thylakoides d'algues brunes." Paris 6, 1988. http://www.theses.fr/1988PA066120.
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Desquilbet, Thibaut. "L'appareil photosynthétique de la Rhodophycée unicellulaire Rhodella violacea : étude des effets de la carence en fer et des états d'agrégation des complexes chlorophylle-protéines." Paris 6, 2003. http://www.theses.fr/2003PA066093.
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Fraser, Niall Johnston. "Modified pigments and mechanisms of energy transfer in LH2 complexes from purple bacteria." Thesis, University of Glasgow, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301678.
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Gomes, Yara Feliciano. "Otimiza??o do processo de s?ntese do aluminato de cobalto via m?todo de polimeriza??o de complexos (MPC) atrav?s do planejamento fatorial fracionado." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12768.
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Previous issue date: 2012-12-20In the ceramics industry are becoming more predominantly inorganic nature pigments. Studies in this area allow you to develop pigments with more advanced properties and qualities to be used in the industrial context. Studies on synthesis and characterization of cobalt aluminate has been widely researched, cobalt aluminate behavior at different temperatures of calcinations, highlighting especially the temperatures of 700, 800 and 900? C that served as a basis in the development of this study, using the method of polymerization of complex (CPM), economic, and this method applied in ceramic pigment synthesis. The procedure was developed from a fractional factorial design 2 (5-2) in order to optimize the process of realization of the cobalt aluminate (CoAl2O4), having as response surfaces the batch analysis data of Uv-vis spectroscopy conducted from the statistic software 7.0, for this were chosen five factors as input variables: citric acid (stoichiometric manner), puff or pyrolysis time (h), temperature (? C), and calcinations (? C/min), at levels determined for this study. By applying statistics in the process of obtaining the CoAl2O4 is possible the study of these factors and which may have greater influence in getting the synthesis. The pigments characterized TG/DSC analyses, and x-ray diffraction (XRD) and scanning electron microscope (SEM/EDS) in order to establish the structural and morphological aspects of pigment CoAl2O4, among the factors studied it were found to statically with increasing calcinations temperature 700?< 800 <900 ?C, the bands of Uv-vis decrease with increasing intensity of absorbance and that with increasing time of puff or pyrolysis (h) there is an increase in bands of Uv-vis proportionally, the generated model set for the conditions proposed in this study because the coefficient of determination can explain about 99.9% of the variance (R?), response surfaces generated were satisfactory, so it s possible applicability in the ceramics industry of pigments
Na ind?stria cer?mica utilizam-se cada vez mais pigmentos de natureza predominantemente inorg?nica. Os estudos nessa ?rea permitem desenvolver pigmentos com qualidades e propriedades mais avan?adas para serem empregados em ?mbito industrial. Estudos de s?ntese e caracteriza??o do aluminato de cobalto t?m sido amplamente pesquisados, o comportamento do aluminato de cobalto em diferentes temperaturas de calcina??es, destacando principalmente as temperaturas de 700, 800 e 900?C utilizando o m?todo de polimeriza??o de complexos (MPC), m?todo este, econ?mico e aplicado em s?ntese de pigmentos cer?micos. O procedimento foi desenvolvido a partir de um planejamento fatorial fracionado 2(5-2) com o objetivo de otimizar o processo de realiza??o do aluminato de cobalto (CoAl2O4), tendo como superf?cies de respostas os dados da an?lise de espectroscopia do Uv-vis realizados a partir do software statistic 7.0, para isso, foram escolhidos cinco fatores como vari?veis de entrada: concentra??es de ?cido c?trico (de maneira estequiom?trica), tempo de puff ou pir?lise (h), temperatura (?C), tempo e taxas de calcina??es(?C/min), em patamares determinados para este estudo. Atrav?s da aplica??o estat?stica no processo de obten??o do CoAl2O4 foi poss?vel estudar entre estes fatores quais possam ter maior influ?ncia na obten??o da s?ntese. Os p?s-precursores foram caracterizados pelas an?lises termogravim?tricas TG/DSC, e os p?s-calcinados (pigmentantes) foram analisados pela difra??o de raios- x (DRX) e microscopia eletr?nica de varredura com energia dispersiva (MEV/EDS) a fim de comprovar os aspectos estruturais e morfol?gicos do CoAl2O4, entre os fatores estudados estaticamente verificou-se que com o aumento da temperatura de calcina??o 700<800<900?C, as bandas do Uv-vis diminuem com o aumento da intensidade da absorb?ncia e que com o aumento do tempo de puff ou pir?lise (h) h? um aumento das bandas do Uv-vis proporcionalmente, o modelo gerado ajustou-se para as condi??es propostas neste estudo, pois o coeficiente de determina??o consegue explicar cerca de 99,9%, da vari?ncia (R?), as superf?cies de respostas geradas foram satisfat?rias, sendo assim sua poss?vel aplicabilidade na ind?stria cer?mica de pigmentos
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Malien-Aubert, Céline. "Colorants à base d'anthocyanes : composition en pigments et copigments et mécanismes chimiques associés à la stabilité de la couleur." Avignon, 2001. http://www.theses.fr/2001AVIG0212.
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L'utilisation de pigments naturels extraits de plantes est devenue une réalité économique face aux récentes interdictions de colorants artificiels pour des raisons toxicologiques. Les anthocyanes, déjà connues pour leur coloration rouge dans les vins ou les jus de fruits, sont très recherchées. Cependant, ces anthocyanes, sont sensibles à plusieurs facteurs physico-chimiques : température, lumière, pH, ions métalliques, oxydations enzymatiques. Si ces pigments sont naturellement protégés dans leur environnement cellulaire végétal ; une fois extraits, ils deviennent très instables. L'étude de la stabilité de quelques colorants a été étudiée en solution à différents pH, sous l'influence de la température et de la lumière, simulant ainsi un vieillissement accéléré des colorants. Pour un pH donné, la stabilité de la couleur rouge est principalement dépendante de la structure des anthocyanes et des autres composés phénoliques incolores. Les colorants riches en anthocyanes acylées montrent une plus grande stabilité due au phénomène de copigmentation intramoléculaire, alors que pour les colorants ne possédant pas d'anthocyanes acylées, c'est la copigmentation intermoléculaire qui joue un rôle clé dans la stabilité de la couleur. En effet, les colorants riches en flavonols et possédant un ratio copigment/pigment élevé montrent une stabilité remarquable. D'autre part, il semblerait que la stabilité de la couleur soit améliorée quand le degré de polymérisation des flavan 3-ols augmente. De plus, le phénomène de copigmentation intermoléculaire peut être renforcé en présence de cations métalliques tels que Fe3+. En conclusion, la stabilité des colorants riches en anthocyanes est fortement dépendante de la structure des pigments et des copigments présents dans la source et de la forte réactivité des molécules d'anthocyanes avec son environnement physico-chimique. Des études ultérieures se tourneront vers des solutions modèles plus complexes, pouvant combiner les anthocyanes avec d'autres substances comme les amino-acides, l'acide ascorbique et les protéines qui pourraient influencer la stabilité de la couleur
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Bekka, Yasmina. "Composition pigmentaire et polypeptidique des complexes pigments-protéines de deux algues brunes macrophytes isolés par électrophorèse." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37602711f.
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Bekka, Yasmina. "Composition pigmentaire et polypeptidique des complexes pigments-proteines de deux algues brunes macrophytes isoles par electrophorese." Paris 6, 1987. http://www.theses.fr/1987PA066678.
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Cinq complexes de plastes d'algues brunes sont separes par electrophorese et analyses. Par comparaison avec les vegetaux verts, on differencie trois types de complexes ayant des compositions en pigments differentes; ce qui suggere une organisation structurale et fonctionnelle assez differentes
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Parot, Pierre. "Etudes structurales et dynamiques de complexes pigments-protéines isolés à partir de bactéries photosynthétiques mésophiles et thermophiles." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37608671g.
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Parot, Pierre. "Etudes structurales et dynamiques de complexes pigments-protéines isolés à partir de bactéries photosynthétiques mésophiles et thermophiles." Aix-Marseille 2, 1987. http://www.theses.fr/1987AIX22067.
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Hu, Qinghui. "Isolation and structural and spectral characterization of the light-harvesting pigment-protein complexes and their polypeptides from the purple bacterium Rhodocyclus tenuis /." [S.l.] : [s.n.], 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10846.
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Lavaud, Johann. "Stratégies d'adaptation des diatomées phytoplanctoniques aux variations de l'intensité lumineuse rencontrées dans leur environnement naturel." Paris 6, 2002. http://www.theses.fr/2002PA066212.
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Garczarek, Laurence. "Caracterisation biochimique et genetique des complexes pigment-proteines chez le procaryote marin prochlorococcus : origine evolutive et role dans l'adaptation de l'appareil photosynthetique aux conditions lumineuses." Paris, Institut national d'agronomie de Paris Grignon, 2000. http://www.theses.fr/2000INAP0023.
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Les complexes pigments-proteines de l'appareil photosynthetique jouent un role primordial dans la capacite d'adaptation a la lumiere des organismes oxyphototrophes. Afin de mieux comprendre les mecanismes impliques dans les processus de photoacclimatation (au sens physiologique du terme) et/ou de photoadaptation (au sens evolutif du terme), le modele utilise lors de cette etude a ete le procaryote marin prochlorococcus qui, dans la nature, peut croitre et photosynthetiser dans une gamme de lumiere couvrant environ 4 ordres de magnitude. La caracterisation biochimique du photosysteme i de prochlorococcus a permis de montrer que les proteines du centre reactionnel (psaa et psab) fixaient de la chlorophylle b et que deux proteines mineures, psaf et psal, presentaient des divergences importantes par rapport a celles des cyanobacteries typiques possedant des phycobilisomes. Ce photosysteme etant particulierement bien conserve parmi les organismes oxyphototrophes, ces modifications ont probablement des implications sur les proprietes biophysiques et biochimiques de ce complexe. La specificite la plus remarquable de l'appareil photosynthetique de prochlorococcus est sans doute la multiplication du nombre de copies du gene codant l'antenne collectrice (pcb) chez les souches adaptees a faible lumiere (5-7 copies), alors qu'une seule copie de ce gene est presente chez les souches adaptees a forte lumiere. Ce phenomene, qui semble resulter d'une adaptation a long terme aux differentes niches lumineuses presentes dans les oceans, est probablement l'un des facteurs principaux responsables des differences pigmentaires et physiologiques observees entre ces deux ecotypes de prochlorococcus. Le controle au niveau transcriptionnel de l'expression
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Capo-Chichi, Kokou Tamégnon Eugène. "Matériaux complexes et couleur : hiérarchisation des paramètres et prévision de la couleur dans un béton coloré." Montpellier 2, 1996. http://www.theses.fr/1996MON20208.
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La contribution du present travail est relative a l'etude de la coloration du beton en terme de parametres mesurables grace a la colorimetrie. Il permet aussi d'obtenir des produits en beton colore de qualite. Apres un rappel sur la couleur, les matieres premieres et le beton colore, ce memoire presente les resultats destines a montrer l'influence des parametres de coloration sur la couleur du beton. Nous etudions ainsi l'influence des parametres de composition et de mise en uvre tels que le rapport eau sur ciment, la nature et le dosage de pigments, la couleur et la distribution granulometrique des granulats, la vibration, la temperature et l'hygrometrie, etc. L'etude montre que le pigment, l'eau et les fines du sable sont les elements determinants de la couleur des betons ou mortiers colores. Parmi d'autres resultats, on montre que les pigments mineraux sont inertes et n'influencent pas le comportement chimique du beton. Aussi, les mesures de couleur effectuees sur de nombreux echantillons de betons colores montrent que les couleurs deviennent moins saturees. D'ou le probleme de la durabilite du beton colore. Nous avons egalement utilise la theorie de kubelka munk pour etudier la prevision de la couleur de mortier et pate pure. Elle nous permet d'evaluer la contribution respective du pigment, du sable et de l'eau a la couleur des materiaux cimentaires. Ceci permet de mieux maitriser les divers parametres de coloration du beton
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Onelli, Olimpia Domitilla. "Complex photonic structures in nature : from order to disorder." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273768.
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Structural colours arise from the interaction of visible light with nano-structured materials. The occurrence of such structures in nature has been known for over a century, but it is only in the last few decades that the study of natural photonic structures has fully matured due to the advances in imagining techniques and computational modelling. Even though a plethora of different colour-producing architectures in a variety of species has been investigated, a few significant questions are still open: how do these structures develop in living organisms? Does disorder play a functional role in biological photonics? If so, is it possible to say that the optical response of natural disordered photonics has been optimised under evolutionary pressure? And, finally, can we exploit the well-adapted photonic design principles that we observe in Nature to fabricate functional materials with optimised scattering response? In my thesis I try to answer the questions above: I microscopically investigate $\textit{in vivo}$ the growth of a cuticular multilayer, one of the most common colour-producing strategies in nature, in the green beetles $\textit{Gastrophysa viridula}$ showing how the interplay between different materials varies during the various life stages of the beetles; I further investigate two types of disordered photonic structures and their biological role, the random array of spherical air inclusions in the eggshells of the honeyguide $\textit{Prodotiscus regulus}$, a species under unique evolutionary pressure to produce blue eggs, and the anisotropic chitinous network of fibres in the white beetle $\textit{Cyphochilus}$, the whitest low-refractive index material; finally, inspired by these natural designs, I fabricate and study light transport in biocompatible highly-scattering materials.
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Swan, Paul Lombard. "Synthesis of mixed ligand, water soluble square planar platinum (II) complexes and an investigation of their association with haematin and potential to inhibit the formation of synthetic malaria pigment." Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/9782.
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Includes bibliography.To establish their potential as a template for novel anti-malarial drugs, a series of planinum (II) complexes were synthesised, their association with haematin determined in 40 aqueous DMSO, pH 7.4 at 25°C and their ability to inhibit the formation of β-haematin (synthetic malaria pigment) was investigated. The compounds synthesised and investigated contained a platinum (II) ion coordinated to acylthiourea and diimine ligands. The diimines used included both substituted and unsubstituted 2,2’-bipyridines and 1,10-phenanthrolines. 2-phenyl pyridine was also utilised as a ligand. It has been shown that the uncoordinated planar ligands interact weakly with haematin with a log K in the range of 1.9 and 3.3 while the twisted or more sterically hindered ligands show no observable association with porphyrin. A series of complexes having platinum coordinated which was reflected in association constant log K values in the range of 4.8 to 5.8. Using a 1,10-phenanthroline ligand in place of a 2,2-bipyridine ligand increased the association constant of the platinum complex, resulting in this series of complexes having log K values in the range of 5.8 to 6.2. It has been shown that when platinum (II) is coordinated to diimines, it is the electron withdrawing properties of the metal which result in the strong association between the diimine containing complex and haematin. Finally both the complex containing platinum cis to two acylthiourea ligands as well as a platinum complex containing 2-phenyl pyridine were shown to have no observable interaction with haematin.
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Bruno, Robert. "Etude de la structure et des interactions au sein des complexes protéine pigments impliqués dans la photosynthèse bactérienne contribution de la spectrométrie Raman de résonance /." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376094239.
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Asto, Ramos Esteban Elvis. "Pigmentos del Complejo Arqueológico Tambo Colorado: un estudio de su procedencia mediante difracción de rayos-X sincrotrón y Método de Rietveld." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2019. https://hdl.handle.net/20.500.12672/11131.
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Manifiesta que el complejo Tambo Colorado es uno de los sitios arqueológicos más impresionantes de la costa sur peruana, localizado en la margen derecha del valle de Pisco. Sin embargo, puede constatarse el estado alarmante de las degradaciones, particularmente de las pinturas de sus murales, justificando una intervención urgente para conservar y proteger este complejo. El objetivo principal de este trabajo está motivado por este propósito de conservación. Resultados de proyectos anteriores muestran una similitud en la composición mineralógica de los pigmentos arqueológicos y geológicos, con la diferencia de la presencia de sales en estos últimos, lo cual se presume se debe a contaminación externa. A fin de confirmar esta hipótesis, en el presente estudio han sido investigados pigmentos geológicos extraídos de vetas a mayor profundidad de la cantera. Los resultados han sido comparados con aquellos correspondientes a los pigmentos de mural del Palacio Norte del complejo para determinar su procedencia, objetivo principal del presente trabajo. Estos resultados han permitido alcanzar los objetivos de la investigación y han confirmado la hipótesis de trabajo. La caracterización de las muestras fue realizada por la técnica de difracción de rayos X, utilizando radiación sincrotrón, de acuerdo al método del polvo. El análisis de la reflectividad fue realizado por el método de Rietveld, para la determinación cualitativa y cuantitativa de la composición de las muestras.Tesis
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Nafis, Mohammed. "Etude spectroscopique de l'hypericine et de ses complexes métalliques en relation avec leur activité photodynamique." Grenoble 1, 1993. http://www.theses.fr/1993GRE10117.
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L'hypericine, pigment naturel dont la phototoxicite est remarquable, pourrait etre utilisee en phototherapie. La deprotonation a ph>10 se traduit par un effet bathochrome sur le spectre d'absorption. La complexation par un des cations des metaux (al, gd, tb, fe, cu) dans la region ou se situent les groupes carbonyle et hydroxyle s'accompagne, de maniere analogue, d'un deplacement de ce spectre vers le rouge. Nous avons determine les constantes de formation des complexes metalliques de l'hypericine du type (hyp-m) ou (hyp-m2). Les proprietes spectroscopiques et photophysiques des complexes metalliques de l'hypericine ont ete etudiees en liaison avec leurs proprietes phototoxiques. L'etude cinetique de l'oxydation du 1,3-diphenylisobenzofuranne montre que les complexes metalliques de l'hypericine photosensibilisent avec un bon rendement la formation d'oxygene singulet. L'irradiation d'une solution aeree d'hypericine, conduit aussi a la formation du radical anion superoxyde a partir de la reduction de l'oxygene par une semiquinone. Cette formation sensibilisee a ete demontree a l'aide de la reduction du cytochrome c. Les complexes metalliques de l'hypericine peuvent etre utilises comme agents phototherapeutiques
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Jarrige, Raphaëlle. "Détermination des propriétés optiques de matériaux granulaires." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00831549.
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La caractérisation de matériaux diffusants, tels les pigments, par leur indice optique complexe demeure actuellement un véritable challenge. Cet indice est la caractéristique intrinsèque au matériau, et est de ce fait, indispensable pour la simulation d'effets colorés et peut, dans le champ de la conservation-restauration, permettre la mise en place d'une méthode d'identification non-ambigüe des matériaux composant les œuvres d'art. L'objectif de cette recherche est d'élaborer une méthodologie permettant de déterminer l'indice optique complexe de ce type de matériaux. Elle constitue l'étape primordiale à l'élaboration d'une base de données d'indices optiques des pigments. Dans un premier temps, une étude théorique des phénomènes conjoint de diffusion et d'absorption résultant de l'interaction d'une onde électromagnétique avec un diffuseur, ou un ensemble de diffuseurs homogènes et sphériques, est développée. Elle consiste à définir l'influence des paramètres intrinsèques (des matériaux) et morphologiques (d'un milieu) sur les résultats obtenus lors de la résolution de l'équation du transfert radiatif (ETR) traité par la méthode 4-flux et de la théorie de Mie dans le sens direct. Dans un second temps, nous aborderons le problème inverse. À savoir, dans notre cas, remonter à l'indice complexe de particules diffusantes à partir des propriétés optiques de la couche. Nous illustrerons cette approche par l'étude d'un pigment rouge, le cinabre. Le modèle de calcul développé prend en compte les flux diffus et les flux spéculaires, mesurés sur les échantillons par spectrophotométrie couplée à une sphère d'intégration dans le domaine du visible
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MOUCHE, Fabrice. "Etude structurale de macromolécules biologiques par cryomicroscopie électronique, reconstruction tridimensionnelle et recalage de données de cristallographie aux rayons X." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2001. http://tel.archives-ouvertes.fr/tel-00006224.
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Parmi les disciplines représentatives de la biostructure, la cryomicroscopie électronique permet, au travers de techniques adaptées, d'atteindre de hautes résolutions. Mon travail a porté sur l'étude d'une catégorie de molécules, les particules isolées à faible degré de symétrie et entre autres sur les pigments respiratoires extracellulaires tels que les hémocyanines de céphalopodes (Vampyroteuthis infernalis, Benthoctopus species, Sepia officinalis) et une hémoglobine d'annélide (Lumbricus terrestris). Une approche empirique a été retenue, et nous a permis de différencier les informations techniques et les données biologiques. Le premier but, basé sur l'utilisation d'un matériel biologique connu, était de travailler sur les techniques d'observation de l'échantillon, d'analyse des images, de reconstruction et de correction des structures. Le deuxième but était d'apporter des réponses de type biologique, par le biais de ces améliorations techniques. Le début de ma thèse fut lié à l'utilisation d'un microscope équipé d'un cristal de LaB6, ne permettant pas de descendre significativement sous la barre des 20 Å. Néanmoins, il nous a permis de répondre à une question de type phylogénétique (Benthoctopus species et Vampyroteuthis infernalis appartiennent à des ordres frères), et de démontrer l'importance du type de microscope et de la source électronique associée. Naturellement, l'étape suivante fut d'accéder à un microscope équipé d'un canon à émission de champ. L'accès sporadique et sur de courtes périodes à ce type de microscope, dont les premiers exemplaires sont arrivés en France en 2000, ne m'ont pas permis de tester systématiquement tous les modes d'utilisation. Malgré tout, les résultats que nous avons obtenu ont validé les avantages de l'émission de champ. Certes, la barre des 6-7 Å de résolution, donnant partiellement accès aux informations relatives à la structure secondaire des protéines, n'a pas encore été atteinte, mais il apparaît que les progrès que nous avons effectués tendent vers cette valeur. Cette progression repose en partie sur l'amélioration des méthodes de collecte des images, de reconstruction et de correction de la fonction de transfert de contraste.
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Sonet, Ventosa Adrià. "Decoherence-assisted transport in pigment protein complexes." Thesis, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-228406.
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Two chlorophylls of the FMO complex, the light-harvesting complex of the green sulfur bacteria, are modeled as two coupled qubits, each surrounded by one spin-bath simulating the environment. The dynamics of the system at a non-zero temperature provide exact analytical expressions for the transition probability and the coherence. It is shown that the decoherence-inducing interaction with the environment enhances the electronic energy transfer. Also the correlations in terms of entanglement and nonlocality are quantitatively studied, sensitively differing when introducing a decay term to resemble both chlorophylls being in their ground states. It is proved that nonlocality is a stronger form of correlation than entanglement.
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Lu, Linag-Suei, and 呂良穗. "Study of the pigment-protein complex cycle and thylakoid stacking of black bean cotyledon." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/20590070937981099199.
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碩士國立臺灣大學
植物學研究所
88
The present study is try to describe the changes in non-leaf green tissue of cotyledons of black bean（Glycine max. L. Merrilx）during seed ripening、desiccation and germination, including the changes in plastids morphology、thylakoid stacking、photosynthetic pigments and the compositions of pigment-protein complexes. During seeds ripening, guard mother cells appeared in the cotyledons. After germination, the stomatal feature and distribution of the adaxial and abaxial regions of cotyledons are very different. There are more stomata on the adaxial region. The plastids of cotyledons of developing seeds in the pods are quite different. They are plastids with irregular shape. Some of them are with only one starch grain and some with aggregate starch grains. All of them have grana stacking without stromal lamelle connecting. In dry seeds, there are more compact thylakoid stacking without flatted grana in the plastids. After imbibition, the thylakoid stacking of grana become looser and multi-direction orientated. After seed germination and seedling exposed to light, there are crystal-shape prolamellar bodies in plastid, from which thylakoids extended to growth and stackness becoming grana. The chlorophyll a/b ratio of the cotyledons of the seeds in the pods was low down between 1.7 and 2.1; after germinaiton, it became 2.8. The changing patterns of contents of total chlorophylls and porphyrins of cotyledons were similar. They decayed during seed ripening and desiccation, and enriched rapidly after germination. In each developmental stages, the mole fraction of three porphyrins revealed periodical fluctuation. The changing pattern of protoporphyrin IX was different from those of Mg-protoporphyrin IX and protochlorophyllide. HPLC profile of xanthophylls showed that the contents of lutein were the highest in cotyledons at all stages of seed. The epioxidation index of seed cotyledons in the pods is about 0.1 lower than that ones after germination. Similar thylakoid protein pattern of mature cotyledons and leaves were revealed by SDS-PAGE gradient gel electrophoresis. In Thornber system electrophoresis, the cotyledons of imbibition seed was deficient CPI pigment-protein complex, and only with CPII. In MARS system electrophoresis, it was deficient A1、AB1 and AB2, and only with AB3. After seed germination and seedling exposed to light, all pigment-protein complexes were recoveried and were similar with the pattern of leaves. This indicated that a phenomenon of pigment-protein complex cycle ( PPCC ) specifically belongs to non-leaf green tissues. Immunocytochemical studies revealed that the colloidal-golds of LHCII b protein were specifically located in grana of cotyledons. This indicated that there are relationship between LHCII b protein and thylakoid stacking.
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Pathirana, Nilangani Nadyeshda. "Mechanisms of complex programmed patterns of anthocyanin pigment formation in Antirrhinum majus : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philsophy in Plant Molecular Biology at Massey University, Palmerston North New Zealand." 2007. http://hdl.handle.net/10179/1385.
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Antirrhinum majus is a model plant used in flower pigmentation studies. Anthocyanin pigment production is mainly controlled by regulation of transcription of the anthocyanin biosynthetic genes. Two types of transcription factors, M Y B and bHLH, together with a WD40 type co-regulator have been shown to regulate the transcription of the anthocyanin biosynthetic genes. In antirrhinum, in addition to the wild type Rosea 1 phenotype, in which pigmentation occurs throughout the inner and outer epidermis of the petal , other complex pigmentation patterns are observed, such as anthocyanins being produced only in the outer (abaxial) epidermis of both lobes and upper tube region of the dorsal petals (roseadorsea phenotype). The major objective of this research project was to understand the genetic regulatory system leading to the development of the two different floral pigmentation patterns in antirrhinum as a means to understanding differential regulation of gene expression in similar cells. Promoter deletion analysis coupled with linker scanning mutagenesis identified the - 1 62 bp to - 1 20 bp region of the Rosea l promoter as i mportant for the regulation of the Rosea l gene. Four putative transcription factor-binding sites within this region : a Wbox, a pyrimidine box, a DOF and a WRKY transcription factor binding site were shown to be important for Rosea l gene regulation. Promoter deletion analysis carried out on the rosea ldorsea promoter showed that the proximal 1 87 bp deletion was, surprisingly, not responsible for the roseadorsea phenotype. Cloning and characterisation of the Rosea l promoter sequence from various Antirrhinum species and accessions verified this finding. The rosealdorsea promoter analysis also indicated that - 1 5 1 bp of the promoter was sufficient for its expression as well as for the maintenance of petal specific expression. The rosea ldorsea allele was also shown to encode a functional protein . In situ hybridisation analysis showed that Rosea l transcripts were present in the inner and outer epidermis of the petal tissue of both wild type and roseadorsea petal tissue. Vascular expression of the Roseal mRNA is indicative of regulation of this gene through sugar or hormonal cues. However, rosea ldorsea transcript levels (in roseadorsea) were much lower than Roseal (wild type). Lowered expression of rosea ldorsea transcripts may be responsible for the overall weak pigmentation in the roseadorsea flowers. Analysis of the intron sequences of the two alleles revealed that many sequence changes were present in the intron 2 of rosea l dorsea. These changes may lead to instability or the lower expression of the rosea l dorsea mRNA and may be responsible for the roseadorsea phenotype. Another possibility is that a fourth Myb gene may be responsible for the roseadorsea phenotype. The role of the Deficiens gene in direct regulation of Rosea l was analysed by RNAi and bioinformatics-based methods. The presence of potential MADS box binding sites in the intron 2 region of the Roseal allele indicated that Rosea l might be directly regulated by Deficiens. Initial experiments using transient assays did not support this suggestion. However, silencing of Deficiens in wild type antirrhinum buds led to the loss of anthocyanin pigments in the petals. Further analysis of the RNAi tissue using SEM revealed that the proper development of conical shaped epidermal cells was also affected . The RNAi tissue also developed chlorophyll pigments underscoring the plasticity of petal identity. This work demonstrated that proper expression of Deficiens is required throughout flowering for anthocyanin pigment production as well as maintenance of petal cell identity. The current investigation revealed that the higher order regulation of the Rosea l alleles in antirrhinum petals is much more complex than initially postulated.
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Hofmann, Clemens [Verfasser]. "Pigment pigment interactions and protein dynamics in light harvesting complexes : a single molecule study / von Clemens Hofmann." 2004. http://d-nb.info/971750483/34.
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HERBSTOVÁ, Miroslava. "Structure and function of pigment-protein complexes of photosynthetic microorganisms." Doctoral thesis, 2010. http://www.nusl.cz/ntk/nusl-79873.
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Biochemical and biophysical methods in combination with electron microscopy were used to investigate structure and function of pigment-protein complexes in thylakoid membranes of various photosynthetic organisms.
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lee, yee-chen, and 李翼丞. "Study on photosynthetic pigment-protein complexes in silkworm larva digestive tract." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/17199313291905232424.
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碩士中國文化大學
生物科技研究所
91
The digesting, transformation, absorption, transport and utilization, of chlorophylls and their physiological function in animals are still a myth. It is worthy to study if chlorophyll- or porphyrin-related compounds (CRCs or PRCs) play any role in animal. In this study, the red fluorescent protein (RFP) of silkworm (Bombyx mori) was employed to explore the above question. RFP has been known to be antivirus in the digestive juice of silkworm. Absorption spectrophotometer, high performance liquid chromatography, Thornber and MARS electrophoresis system and western blotting were hired to analyze the biochemical characteristics of mulberry leaf、RFPI in the digestive juice, and RFPII on the digestive tract. Data show that mulberry leaf、RFPI and RFPII are very different. By using a reversed-phase HPLC system chlorophyll a and b (Chl a and b) were found in RFPI purified according to Hou and Chiu (1986). The result is different from that of Hayashiya (1978) and Uchida and Hayashiya (1981), who reported that RFPI contained only chlorophyllide a (Chlide a).The Thornber and MARS electrophoresis systems and western blotting show both RFPI and RFPII contain four apoproteins of pigment-protein complexes of mulberry leaf, including RCIa、LHCIIa、LHCIIb and LHCIIc. Combination of the above data suggest that pigments and proteins of RFP I and RFPII might be totally or partially and directly or indirectly tranformed from pigment-protein complexes responsible for photosynthesis in mulberry leaf. It is therefore suggested that there may be a new model of assimilate nutrients in silkworm larvae.
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GARDIAN, Zdenko. "Electron microscopic studies of photosynthetic membranes and their pigment-protein complexes." Doctoral thesis, 2009. http://www.nusl.cz/ntk/nusl-49142.
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McClure, Scott. "Investigation of Light-harvesting Dynamics of Photosynthetic Pigment-protein Complexes using Ultrafast Spectroscopy." Thesis, 2013. http://hdl.handle.net/1807/43214.
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We investigate the ultrafast electronic excitation dynamics of phycobiliproteins from cryptophyte algae using two-dimensional electronic spectroscopy and frequency-resolved transient absorption spectroscopy. We detail the development of a transient absorption spectrometer that utilizes balanced and fast detection methods to reduce noise and maintain high temporal and spectral resolution. We observe coherent oscillations and attribute them to vibrational coherences using the wave packet formalism. Analysis of the dynamic Stokes shift and motion of the wave packet on the potential-energy surface indicate the coherences are predominantly situated in the excited electronic state of the protein. These measurements imply that the ultrafast energy transfer within phycobiliproteins is coupled to the vibrational motion of its constituent chromophores. We demonstrate the capability and necessity of multiple ultrafast spectroscopic techniques for determining the origin of coherent motion in photosynthetic light-harvesting complexes.
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Kvíčalová, Zuzana. "Dynamika tripletních stavů pigmentů ve fotosyntetických světlosběrných komplexech." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-313972.
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Chlorophyll molecules in their triplet excited state can react with the ground state oxygen, producing oxygen in a singlet excited state, which is very reactive and thus very harmful to the light-harvesting complex. Photosynthetic organisms employ carotenoids to prevent the damage by quenching both excited (singlet) states of oxygen and excited triplet states of chlorophyll. In this work, we use ns transient absorption spectroscopy and global analysis to study the dynamics of carotenoid and chlorophyll triplet states in two light-harvesting complexes of Amphidinium carterae, the Peridinin-Chlorophyll a-Protein complex (PCP) and the main light-harvesting complex (LHCP). It appears that at room temperature all triplets are transferred from chlorophylls to carotenoids within ~ 5 ns, providing a very efficient protection against formation of singlet oxygen. One carotenoid triplet with a lifetime of ~ 10.2 µs participating in the chlorophyll triplet quenching was observed in the PCP sample, while results from LHCP suggest that two carotenoid triplets with a similar lifetime of ~ 2.5 µs contribute to quenching of chlorophyll triplet states. The two carotenoid triplets are attributed to peridinin placed in a polar environment and peridinin placed in a non-polar environment in the LHCP complex.