Face à la limite de la littérature sur l’impact de l’environnement notamment alimentaire dans le vieillissement oculaire liée en partie aux manques de données en population générale particulièrement la plus âgée en France, nous nous sommes intéressés dans un premier temps, aux relations entre l’alimentation, les xanthophylles plasmatiques et le pigment maculaire puis sa distribution spatiale et dans un second temps, au profil des acides gras et les signes de sécheresse oculaire chez les 1153 participants de l’étude Montrachet.Dans un premier temps, nous avons mis en évidence une augmentation de la concentration plasmatique de lutéine et zéaxanthine chez les personnes consommant fréquemment des courges et courgettes et ainsi, une augmentation de la densité optique du pigment maculaire chez les personnes âgées non-fumeurs ayant une concentration plasmatique élevée en lutéine. De plus, nous avons fourni des valeurs du pigment maculaires qui pourraient servir de référence en population générale pour des études épidémiologiques. Nos résultats sont très cohérents avec ceux des autres études épidémiologiques même si notre population est en moyenne plus âgée. Par ailleurs, nous avons montré que les signes de la sécheresse oculaire sont plus fréquents chez les personnes âgées ayant des concentrations plasmatiques faibles en acides gras polyinsaturés et saturés. Ainsi, nos résultats apportent des éléments nouveaux dans l’implication des acides gras dans le processus de la sécheresse oculaire.Enfin, ces travaux de thèse, viennent enrichir la littérature relative au pigment maculaire, sa densité, sa répartition spatiale et ses déterminants ainsi que les déterminants de la sécheresse oculaire. Cependant, compte tenu de caractère transversal de nos études, ces résultats permettent seulement d’émettre des hypothèses qui seront confirmées à l’aide d’études longitudinales et pourraient contribuer à conforter l’intérêt des interventions reposant sur des supplémentation en caroténoïdes xanthophylles. / Given the limits of the literature on the environmental nutritional impact in ocular aging witch is partially due to the lack of data in general population notably in French elderly, first, we were interested in the relationships of diet, plasma xanthophylls and macular pigment optical density as well as its spatial distribution and second of plasma fatty acids and dry eye disease signs in the 1153 Montrachet study participants.Firstly, we reported the high consumption of squash, the high plasma lutein and zeaxanthin levels and also the high plasma lutein level, the high macular pigment optical density level in nonsmokers subjects. In addition, the macular pigment values we provided in the study could be used as reference in population based study. Our results are very consistent with those found in other epidemiological studies even though our population is on average older. Secondly, we have shown that dry eye disease signs are more frequent in elderly subjects with low plasma polyunsaturated and saturated fatty acids level. Thus, our results provide new elements in the involvement of fatty acids in the process of dry eye disease.Finally, this work enriches the literature on macular pigment, its density, as well as its spatial distribution and its determinants as well as the determinants of dry eye disease. However, given the transversal nature of our studies, these results make only possible to formulate hypotheses that will be confirmed with longitudinal studies and could reinforce the interest of interventions based xanthophylls carotenoids supplementation in elderly.

Phenolic compounds play an important role in red wine colour, bitterness, astringency, as well as a range of other tactile or 'mouth-feel' characteristics. Progressive changes of phenolic compounds, initially extracted from grapes, occur during the storage and aging of red wines. The decrease of astringency occurring during wine aging has been considered as a result of mainly anthocyanin-flavanol condensation either directly or mediated by aldehydes. The contribution of these polymeric pigments formed during wine aging to the unique properties of red wine is an important question still unanswered. Experiments were conducted to synthesise polymeric pigments in model wine solutions under different conditions in the absence of acetaldehyde to provide material for chemical and sensory studies. Only small amounts of polymeric pigments were formed in these experiments confirming that direct polymerisation is a slow process. The low yield of polymers made it necessary to investigate the isolation of polymeric pigments directly from wine. A preparative fractionation protocol was developed to obtain fractions enriched in different red wine pigment combinations for further investigation. A HPLC method was also developed that separated the pigmented and non-pigmented polymers, as well as the monomeric anthocyanins, flavanols (monomeric to trimeric), flavonols and hydroxycinnamic acids from each other. A 6 month old and a 5 year old Shiraz wine were fractionated and further analysed by acid hydrolysis in the presence of a nucleophile, gel permeation chromatography (GPC) and by different mass spectrometry techniques. The various fractions isolated from the 6 month old wine contained combinations of pentameric to dimeric pigments, while those from the 5 year old wine contained pigments with an average degree of polymerisation (DP) of at least 11 but possibly up to 32. Experiments were conducted to determine the sensorial contribution of anthocyanins to wine as well as the effect of anthocyanin-flavanol polymerisation reactions taking place during maturation. It was shown that significant changes occur in the polymeric phenol composition and in the mean degree of polymerisation of Shiraz wine during aging. With aging more skin tannin were incorporated in the pigmented polymers and the percentage of galloylation in these polymers decreased. In order to describe the sensory attributes of the polymeric pigments a refined vocabulary, describing the astringent and other mouth-feel sensations elicited by dry red table wines representing different styles was developed and called the mouth-feel wheel. The developed mouth-feel wheel was used in a study to investigate the contribution of anthocyanins and anthocyanin-proanthocyanidin reaction products to the mouth-feel properties of red wine. Wines were made from both red and white grapes with and without pomace contact, as well as with and without anthocyanin addition to the white grapes. The white wine made like a red wine did not exhibit the same mouth-feel sensory attributes of a red wine: it was lower in viscosity, less particulate in nature and lower in intensity for the astringency descriptors fine emery, dry and grippy. The presence of anthocyanins during fermentation appeared to increase the intensity of astringency related terms. Treatments with added anthocyanins increased the amount of polymeric phenols to twice that when compared to treatments without added anthocyanins. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1345103 / Thesis (Ph.D.) - University of Adelaide, School of Agriculture, Food and Wine, 2008

Cette étude se focalise sur l’influence du dioxyde de titane sur le comportement d’une résine polymère époxy modèle. Les systèmes considérés sont des composites constitués d’un pigment, le dioxyde de titane TiO2 à des taux massiques de 10% et 20%, et de résine DGEBA-DAMP. Tout d’abord, les propriétés mécaniques et thermiques de films libres complètement réticulés sont mesurées par DSC et DMA. Les résultats des composites sont comparés à ceux de la résine pure pour mieux comprendre l’impact du TiO2. Les films libres de composites sont ensuite immergés dans de l’eau pure à différentes températures (30, 40, 50 et 60 °C) pour étudier la prise en eau et les coefficients de diffusion par gravimétrie. L’évolution des propriétés de nos systèmes est aussi étudiée pour avoir accès à l’influence de l’eau sur leur comportement. Dans un second temps, les composites sont réticulés sur des plaques d’acier et certaines sont soumises à des contraintes mécaniques externes. Ces revêtements sont alors plongés dans une solution saline et l’absorption d’eau est suivie par SIE. Une dernière étape de ce travail consiste à suivre le gonflement des revêtements composites par SECM. Finalement, la comparaison des résultats de la résine pure et des composites obtenus pour les films libres et les revêtements permet de mettre en avant l’impact du TiO2 sur la durabilité de ces systèmes, essentiellement dû au développement de contraintes internes. / This study focuses on the influence of titanium dioxide on the behavior of a model epoxy polymer resin. The considered systems are composites which contain titanium dioxide TiO2 as pigment and DGEBA-DAMP as epoxy resin. The studied amounts of titanium dioxide are 10 wt.% and 20 wt.%. Firstly, mechanical and thermal properties of totally cured free films are studied by DSC and DMA. The results of the composites are compared to those of the resin alone to better understand the impact of the titanium dioxide. Then, composite free films are immersed in pure water at different temperatures (30, 40, 50 and 60 °C) to investigate water uptake and diffusion coefficients by gravimetry. At each step of ageing, measurements of the properties are carried out to show the influence of water on our systems behaviors. Then, composites of epoxy resin and pigment are applied on steel panels and some samples are submitted to external mechanical stresses. These coatings are submitted to an environment of NaCl 3 wt.% saline solution and water uptake is followed by Electrochemical Impedance Spectroscopy (EIS). Swelling of composites coatings is followed by SECM in a last step of this work. Finally, a comparison of the results of pure resin and of composite gives access to the impact of titanium dioxide on the durability of these systems. It is mainly due to the presence of internal stresses.

Les organismes marins, dont les microalgues, constituent un champ d’investigation majeur pour la découverte de nouveaux médicaments anticancéreux. Pour mettre en évidence de nouvelles molécules anticancéreuses, nous avons adopté une démarche bioguidée sur des extraits de microalgues marines présentant une activité antiproliférative. Ce travail a conduit à l’isolement de la violaxanthine, pigment caroténoïde époxydé, et à la démonstration de son activité antiproliférative, cytotoxique, pro-apoptotique et pro-nécrotique sur la lignée cellulaire de cancer du sein MCF-7. Des caroténoïdes tels que la fucoxanthine sont déjà connus pour présenter une activité anticancéreuse liée à leur fonction époxyde. Cependant, cette étude est la première à montrer le potentiel de la violaxanthine.Afin d’isoler d’autres pigments microalgaux potentiellement anticancéreux, des méthodes de CLHP efficaces ont été développées pour leur analyse et leur purification. Puis, des méthodes classiques d’extraction de pigments issus de microalgues ont été comparées à des méthodes d’extraction innovantes. Cette étude a permis de montrer l’intérêt de la technologie micro-onde en termes d’efficacité et de rapidité pour l’extraction des pigments de microalgues frustulées (diatomées). Plus largement, ce travail confirme le potentiel des microalgues marines comme source de molécules anticancéreuses, et démontre l’intérêt de la technologie micro-onde pour l’extraction de molécules à activité biologique issues de produits naturels. / Marine organisms, including microalgae, constitute a major field of investigation for the discovery of new anticancer drugs. To obtain new anticancer compounds, we used a bio-guided methodology on microalgae extracts showing antiproliferative activity. This work led to the isolation of violaxanthin, an epoxycarotenoid pigment, and to the demonstration of its antiproliferative, cytotoxic, pro-apoptotic and pro-necrotic activity. Carotenoids such as fucoxanthin are already known to have anticancer activity related to the epoxide. However, this is the first study demonstrating the potential of violaxanthin.In order to isolate other pigments with anticancer activity , efficient HPLC methods were developed for their analysis and purification. Then, conventional methods of pigments extraction from microalgae were compared to innovative methods of extraction. This study demonstrates the interest of microwave technology in terms of efficiency and rapidity for the pigments extraction from frustulated microalgae (diatoms).To conclude, this work confirms the potential of marine microalgae as a source of anticancer drugs, and demonstrates the interest of microwave technology for the extraction of biologically active molecules from natural products.

The objectives of this project were to develop a high performance liquid chromatographic method for separating the pigment esters mixture, to determine the locations of the pigment moiety in the isolated esters using pholosiphases, and to characterize the pigment-protein complex and determine its distribution in other bacteria. Saponification of the two pigment esters 1 and 2 with aqueous KOH yielded two free pigments on TLC plates developed by two solvent systems. The fasters moving of these two free pigments co-chromatographed with the one free pigment produced from each pigment ester by phospholipase A2 treatment. This suggests that the pigment molecule is a methoxy derivative of xanthomonadin and is esterified to the 2-position of the glycerol moiety of each pigment ester. No free pigment was released from phospholipases C and D treatment of the two pigment esters, indicating that pigment is not esterified to the sorbitol or phosphate moiety of pigment esters 1 or 2.

No description available.

Studien har klart och tydligt resulterat i att ett antalspecifika resultat rörande betydelsen av olika materialsammansättningars påverkan kornbildningen. Resultaten visar på vilka orsaker som finns för denna kornbildning samt hur färgsammansättningen kan varieras för att minska detta problem. / A study of grain formation in linseed oil-based paint have been conducted. The grains were formed in linseed oil paints with either Yellow1, Yellow 2, Black, or Red as the pigments. There are two types of grain formation which has been observed from the paint samples. (a) The grains which immediately appear in the newly made paint with Yellow 1, Yellow 2, and Red paints (b) while the other type is the grain that developed as the function of storage time in Black linseed oil paint. The results clearly show the cause of the defects.

<p>The materials and working method of a painting can reveal important information about our cultural history, as well as lend the conservator the necessary knowledge for treatment options. The removal of a cross-section sample reveals the three-dimensional (3d) structure of the painting and can be used to identify materials. However, cross-section samples are destructive and provide only local information. Nonlinear optical ultrafast pump-probe microscopy, originally developed for biomedical imaging, can provide high resolution 3d images with chemical contrast. In this dissertation, I adapt pump-probe microscopy to multiple materials and applications in cultural heritage research. Pump-probe dynamics were found to be sensitive to the ratio of the two chromophores present in the precious blue pigment lapis lazuli and its synthetic analogs, ultramarines blue and violet. Virtual pump-probe cross-sections were combined with nonlinear fluorescence contrast to study differences between the interactions of paper supports with inorganic crystalline pigments and organic dyes. Multiple early Italian paintings (The Crucifixion by Puccio Capanna, The Martyrdom of St. Alexander and The Body of Christ Supported by Angels attributed to Lorenzo Lotto) were imaged in-situ, in conjunction with traditional conservation science methods, as a part of a technical case study. Thus, pump-probe microscopy offers an important new tool for gaining fundamental insights into our cultural heritage.</p> / Dissertation

The thesis describes the effects of various plant flavonoids (curcumin, epigallocatechin-3-gallate [EGCG], luteolin, apigenin, myricetin, quercetin, and cyanidin) on the physiological properties and viability of cultured human retinal pigment epithelial (RPE) cells. It is described that, with the exception of EGCG, all flavonoids tested decrease dose-dependently the RPE cell proliferation, migration, and secretion of VEGF. Luteolin, apigenin, myricetin, and quercetin decreased the viability of RPE cells at higher concentrations, by triggering cellular necrosis. Curcumin decreased the viability of RPE cells via induction of early necrosis and delayed apoptosis. The cytotoxic effect of curcumin involved activation of caspase-3 and calpain, intracellular calcium signaling, mitochondrial permeability, oxidative stress, and increased phosphorylation of p38 MAPK and decreased phosphorylation of Akt protein. Myricetin caused caspase-3 independent RPE cell necrosis mediated by free radical generation and activation of calpain and phospholipase A2. The myricetin- and quercetin-induced RPE cell necrosis was partially inhibited by necrostatin-1, a blocker of programmed necrosis. The author concludes that the intake of curcumin, luteolin, apigenin, myricetin, and quercetin as supplemental cancer therapy or in the treatment of retinal diseases should be accompanied by careful monitoring of the retinal function. Possible beneficial effects of EGCG and cyanidin in the treatment of retinal diseases should be examined in further investigations.

Mammalians process their photoreceptions through lateral eyes; however, non-mammalian vertebrates and invertebrates possess additional extraretinal photoreceptors over their bodies to detect light stimuli. Chromatophores, i.e. dermal specialized pigment cells, play important roles in the regulation of body patterns. Since chromatophores derive from neural crest, they share the common embryonic origin with retina. Recent evidence shows that they are light-sensitive due to opsin expression. In the present study, the expression of seven cone opsins was detected in tilapia caudal fin tissues. Moreover, distinct photoresponses were found in two chromatophore types. Regardless of stimulating wavelengths, melanophores tend to disperse and maintain cell shape at dispersion stage by shuttling pigment granules. Conversely, erythrophores respond to light in a wavelength-dependent manner. The opsin expression profiles of melanophores and erythrophores imply SWS1 and RH2 group genes may play important roles in chromatophore photoresponses. Through measuring photosensitivity, I suggest the two opsins play opposite roles in light-induced translocations of pigment granules within erythrophores: SWS1 for aggregations at UV and short wavelength regions and RH2b for dispersion in middle/long wavelengths. An antagonistic interaction occurs in the overlapping of the absorbance spectra of the two opsins. I also found that the photoresponses take place along with the occurrence of the change of cell membrane potential. In addition, the effect of different light backgrounds (broad spectrum, short wavelength-rich, and red-shifted light conditions) on the photosensitivity of tilapia erythrophores was investigated. I found that the major opsin classes (SWS1 and RH2b) responsible for photoresponses remain constant in three groups of erythrophores. Together, I postulate that melanophores may serve as a light filter in integumentary tissues, and the chromatically antagonistic mechanism enables tilapia erythrophores to sense the subtle change of environmental photic condition and to fine-tune pigmentation. I also investigated the ontogenetic change of photoresponses of rainbow trout melanophores. Distinct photoresponses were found in parrs and smolts. Furthermore, smolt melanophores responded to light in a wavelength-dependent manner. Since the change of coloration and visual system during smoltification of salmonids is regulated by thyroid hormone (TH), I suggest that the development of melanophore photosensitivity is associated to TH as well. / Thesis (Ph.D, Biology) -- Queen's University, 2013-08-27 09:57:22.907