After-cooking darkening (ACD), a gray-black discoloration, is one of the key quality defects of the potato. Previous work using a diploid population 13610 identified 14 single nucleotide polymorphism (SNP) markers, located on eight chromosomes, which have the strongest association with ACD. Seven of these markers are located in four major quantitative trait loci (QTL) on chromosomes 2, 4, 6, and 10. It is hypothesized that these 14 markers would also have significant relationship to ACD in other breeding populations. Therefore, their effects in another diploid population 14946 were analyzed by amplicon genotyping using high-resolution DNA melting (HRM). Eleven of the 14 SNP markers were confirmed to be significantly associated with ACD. Six of the 11 markers were located in the four major QTL regions. In addition, unlabelled probe assays using HRM were performed on a group of clones in the tetraploid population 14945. Five from the 14 markers were analyzed, and three showed significant relationship to ACD. The methodology established and the markers identified in this study could benefit breeding programs for developing lower ACD varieties.

No description available.

L’amélioration des performances des dispositifs pyrotechniques requiert une description fine de la transition choc/détonation (TCD) dans les explosifs. Les modèles de TCD existant comportent une part d’empirisme qu’il est souhaitable de réduire à l’aide de données expérimentales à l’échelle microscopique. Pour cela, nous avons mis au point un dispositif permettant de générer des chocs de 2 à 30 GPa et d’analyser en temps réel l’évolution du matériau par spectroscopie. Le système de mesure comporte un laser sonde et un ensemble de spectroscopie Raman rapide. Ce dispositif a été utilisé pour l’étude des mécanismes d’initiation d’un explosif appelé TATB. L’évolution des spectres Raman en fonction de la pression révèle un couplage entre les modes de vibration des groupements NO2 et NH2 provenant de la présence d’un réseau de liaisons hydrogène au sein du TATB. Ce réseau est responsable de la grande stabilité de la molécule. Quelques différences entre les régimes statique et dynamique, imputables à l’effet du chauffage par le choc, sont mises en évidence ; elles semblent indiquer un affaiblissement du réseau de liaisons hydrogène. Les résultats font également apparaître une atténuation progressive du signal Raman sous choc avec la pression. A partir de 9 GPa, le signal n’est plus détectable. Des visualisations par caméras rapides montrent que cette atténuation du signal Raman est accompagnée d’un assombrissement progressif du TATB qui devient totalement opaque à 9 GPa. Des expériences de réflectivité sous choc ont montré que ces deux phénomènes sont dus à un élargissement de la bande d’absorption du TATB. / Improving performances and safety of pyrotechnic devices requires a sharp knowledge of the shock to detonation transition phenomenon in high explosives. Current models to describe this phenomenon largely involve empiric parameters based on macro scale experiments. To improve predictive capability of these models, it is necessary to get experimental data at a microscopic scale. To provide such data, we developed an experimental setup to shock a high explosive up to 30 GPa and perform in-situ measurement of its Raman spectra under this loading. The device includes a shock generator based on explosive driven plate impact triggered by a laser pulse and a diagnostic involving an excitation laser and a spectrometer coupled with an intensified CCD. This experiment has been applied to an insensitive high explosive named TATB. Pressure driven evolution of the Raman spectra reveals an important coupling between NO2 and NH2 vibration modes that is due to a strong H bonding within TATB crystal. This bonding is clearly linked to TATB high stability. Differences observed between dynamic and static loading are attributed to shock heating resulting in H bonding weakening. Moreover, results show a progressive decrease in Raman spectra intensity with increasing shock pressure down to a complete signal loss at about 9 GPa. High speed visualisations reveal a progressive darkening of the sample leading to complete opacity at 9 GPa. Reflectivity measurements under shock loading show that these two phenomena are due to a shock-induced enlargement of the TATB absorption band.

Cette thèse, financée par la Fondation des Sciences du Patrimoine, Patrima, a pour but la compréhension du mécanisme chimique responsable du brunissement de certains pigments verts à base de cuivre, sous forme de complexes organométalliques, utilisés en peinture de l'Antiquité à la Renaissance. Il s'agit du « vert de gris » et du « résinate de cuivre ». La variation chromatique de ces pigments engendre une perte de lisibilité de l'œuvre et pose un important problème de conservation. La détermination des réactions impliquées dans l'altération est fondamentale pour définir une méthodologie d'intervention. Afin de clarifier le mécanisme responsable du changement de couleur il est nécessaire d'étudier d'une part la géométrie du centre métallique et d'autre part la nature des liaisons cuivre-ligand. Dans ce but une stratégie multianalytique a été développée. Elle est basée sur la reconstitution des composés utilisés par les artistes et de ceux qui peuvent se former dans les couches picturales, et sur leur caractérisation, avant et après un vieillissement accéléré (thermique oupar exposition à la lumière). La synthèse des ces systèmes modèles a permis d'évaluer l'influence de plusieurs paramètres (solvant, pH, température et temps de réaction) sur la structure des complexes. Les produits de départ et les composés de dégradation ont été analysés par différentes techniques. L'étude des morphologies et la répartition chimique du cuivre au sein des systèmes est réalisée par MEB -EDS. La structure moléculaire a été caractérisée par IRTF diffraction des rayons X, spectroscopie d'absorption des rayons X et par résonance paramagnétique électronique. La caractérisation des produits de dégradation présents dans la phase organique est effectuée par chromatographie en phase gazeuse couplée à la spectrométrie de masse. En parallèle l'étude de leurs propriétés optiques a été réalisée par spectroscopie UV-visible. Les données collectées sont comparées à celles obtenues, par les mêmes méthodes analytiques, sur des échantillons de couches picturales prélevés sur des œuvres peintes plus ou moins altérées. Ce travail comparatif a permis à la fois de mieux comprendre les mécanismes de formation et de transformation au cours du vieillissement de ces systèmes hybrides organique-inorganique, d'évaluer quels paramètres ont plus d'influence sur l'altération et de valider ou d'invalider certaines hypothèses proposées concernant les changements des propriétés optiques observées. / This thesis, funded by Patrima, Foundation for Cultural Heritage Sciences, aims to understand the chemical mechanisms responsible for the darkening of some green copper organometallic pigments (Verdigris and copper resinate) widely used in paintings from Antiquity to the Renaissance. The color variation of these pigments involves a loss of legibility of the artwork and is a major conservation issue. The determination of the reactions involved in the alteration is fundamental to define an intervention methodology. In order to clarify the discoloration process it is necessary to get information on the geometry of the copper cluster and the nature of the copper-ligand bonds. With this aim, a multi-analytical methodology has been developed, based on the reconstitution of ancient pigment and of the compounds that can be formed in the paint layer. These model systems have been characterized before and after an accelerated ageing (by heat or light). Their synthesis has permitted to evaluate the influence of several parameters (solvent, pH, temperature and reaction time) on the resulting structure. The original materials and their degradation products have been analyzed by different techniques. The study of the morphology and chemical distribution of copper in the system was performed by SEM-EDS. The molecular structure was characterized by FTIR, XRD spectroscopy, X-ray absorption and EPR (Electronic Paramagnetic Resonance). The characterization of organic degradation products has been carried out by gas chromatography coupled to mass spectrometry. At the same time a study of optical properties has been performed by UV-visible spectroscopy. The data collected are compared to those obtained, by the same analytical methods, on samples of paint layers taken from ancient paintings. This comparative work has permitted to better understand the mechanisms of formation and transformation of these organic-inorganic systems, to assess which parameters influence the alteration, and to validate or invalidate some preliminary hypothesis about the chromatic changes.

Seed coat biochemistry and colour are highly variable in common bean (Phaseolus vulgaris) (syn. dry bean). Genetic studies of dry bean seed coat chemistry and colour have important implications in breeding efforts for improving nutrition and seed quality for consumer acceptance. The results of this thesis detail the phenotypic and genotypic characterization of seed coat post harvest darkening (PHD) in parents and progeny of crosses among them as well as the phenotypic characterization of seed coat condensed tannin (CT) accumulation in five genotypes of bean.<p> Seed coat PHD represents a problem for producers and consumers of several different market classes of dry bean. There are three post harvest darkening phenotypes: (i) non-darkening (ND), (ii) slow darkening (SD) and (iii) regular darkening (RD). The inheritance of PHD was determined by evaluating 28 populations derived from crosses between RD, SD and ND genotypes. Results suggest that at least two major, unlinked genes control the PHD trait in dry bean. Recessive epistasis with three phenotypic classes best explains the segregation ratios observed in populations from crosses between SD and ND parents. One gene, J, is responsible for whether a bean will darken and seeds of plants that are jj do not darken at all. Another gene, SD, influences the rate a seed coat will darken with seed from sdsd individuals darkening more slowly that those with the dominant SD allele. Quantitative evaluation of seed coat PHD demonstrated that there was a wide range of darkening within any given PHD phenotype. Crosses made between the ND x ND cross class resulted in F2 progeny that were all ND, however, a wide range of seed coat background colours was noted in the progeny. In several of the crosses made between ND x RD and SD x RD classes the resulting F1 progeny were all RD; however, a wide range of RD phenotypes were observed in the F2 progeny. These phenotypes are not likely due to quantitative trait loci (QTL) associated with the PHD trait, but rather a result of other chemical reactions occurring in the seed coat. Condensed tannins (CT; syn. proanthocyanidins), kaempferols, polyphenol oxidase (PPO) and possibly other compounds or enzymes may be interacting and causing this quantitative range within any given genotype as a function of environmental variability, genotype and their interaction. CT have been associated with PHD but are not responsible for the major difference between RD and SD lines. They may, however be responsible for the quantitative nature of the phenotype.<p> Condensed tannins can be harmful or beneficial to human health and the environment depending on the amount present and where it is found in the plant. Manipulating the production, accumulation and form of CT in the seed coat of dry bean would be beneficial to bean producers, consumers and breeders. This experiment quantitatively and qualitatively evaluated differences in patterns of CT accumulation in the seed coats of five genotypes of dry bean which exhibited low, medium or high concentrations of CT in their seed coats at maturity. Condensed tannin content was assessed from seeds harvested every other day from 6 40 days after flowering (DAF) using a modified BuOH-HCl assay. Results illustrated that CT accumulated as early in low CT genotypes as in high CT genotypes. CT content stabilized after 14 DAF in low CT genotypes. By contrast, CT content peaked then leveled off 30 DAF in moderate and high CT genotypes. A reduction in CT content in the higher CT lines was observed in the final stages of seed development.

Seed coat biochemistry and colour are highly variable in common bean (Phaseolus vulgaris) (syn. dry bean). Genetic studies of dry bean seed coat chemistry and colour have important implications in breeding efforts for improving nutrition and seed quality for consumer acceptance. The results of this thesis detail the phenotypic and genotypic characterization of seed coat post harvest darkening (PHD) in parents and progeny of crosses among them as well as the phenotypic characterization of seed coat condensed tannin (CT) accumulation in five genotypes of bean.<p> Seed coat PHD represents a problem for producers and consumers of several different market classes of dry bean. There are three post harvest darkening phenotypes: (i) non-darkening (ND), (ii) slow darkening (SD) and (iii) regular darkening (RD). The inheritance of PHD was determined by evaluating 28 populations derived from crosses between RD, SD and ND genotypes. Results suggest that at least two major, unlinked genes control the PHD trait in dry bean. Recessive epistasis with three phenotypic classes best explains the segregation ratios observed in populations from crosses between SD and ND parents. One gene, J, is responsible for whether a bean will darken and seeds of plants that are jj do not darken at all. Another gene, SD, influences the rate a seed coat will darken with seed from sdsd individuals darkening more slowly that those with the dominant SD allele. Quantitative evaluation of seed coat PHD demonstrated that there was a wide range of darkening within any given PHD phenotype. Crosses made between the ND x ND cross class resulted in F2 progeny that were all ND, however, a wide range of seed coat background colours was noted in the progeny. In several of the crosses made between ND x RD and SD x RD classes the resulting F1 progeny were all RD; however, a wide range of RD phenotypes were observed in the F2 progeny. These phenotypes are not likely due to quantitative trait loci (QTL) associated with the PHD trait, but rather a result of other chemical reactions occurring in the seed coat. Condensed tannins (CT; syn. proanthocyanidins), kaempferols, polyphenol oxidase (PPO) and possibly other compounds or enzymes may be interacting and causing this quantitative range within any given genotype as a function of environmental variability, genotype and their interaction. CT have been associated with PHD but are not responsible for the major difference between RD and SD lines. They may, however be responsible for the quantitative nature of the phenotype.<p> Condensed tannins can be harmful or beneficial to human health and the environment depending on the amount present and where it is found in the plant. Manipulating the production, accumulation and form of CT in the seed coat of dry bean would be beneficial to bean producers, consumers and breeders. This experiment quantitatively and qualitatively evaluated differences in patterns of CT accumulation in the seed coats of five genotypes of dry bean which exhibited low, medium or high concentrations of CT in their seed coats at maturity. Condensed tannin content was assessed from seeds harvested every other day from 6 40 days after flowering (DAF) using a modified BuOH-HCl assay. Results illustrated that CT accumulated as early in low CT genotypes as in high CT genotypes. CT content stabilized after 14 DAF in low CT genotypes. By contrast, CT content peaked then leveled off 30 DAF in moderate and high CT genotypes. A reduction in CT content in the higher CT lines was observed in the final stages of seed development.

No description available.

This thesis is an articulatory investigation into phonological variation and change in English /l/-darkening. Although syllable-based accounts of /l/-darkening state that light [l] occurs in onsets (e.g. `leap') and a dark variant in codas (e.g. `peel'), numerous works linking phonology with other subfields of linguistics have shown that this simplified distinction cannot fully account for the variation found. Firstly, /l/-darkening is sensitive to morphosyntactic structure, as shown through overapplication of the process in certain morphosyntactically defined positions: e.g. word-finally in phrases such as `heal it', or stem-finally before a suffix in words such as `healing'. In addition, analyses of /l/-darkening from several phonetic studies have led to some arguing against an allophonic distinction altogether, stating that the difference between light and dark variants is merely two extremes of one continuum. Not only does this interpretation challenge the traditional categorisation of /l/-darkening but, given the clear sensitivity to morphosyntactic boundaries that /l/-darkening displays, it also raises questions for a modular architecture of the grammar if phonetics can be morphologically conditioned. This dissertation is an empirical analysis of /l/-darkening, presenting data from nine varieties of English. Given the difficulty in measuring liquid consonants reliably, ultrasound tongue imaging is used to provide a thorough account of the prime articulatory correlations of darkening processes. The present study provides hitherto absent instrumental evidence confirming the varying degrees of morphosyntactic sensitivity across different dialects. I demonstrate that, rather than being contradictory or chaotic, variation to morphosyntactic boundaries cross-dialectally makes complete sense under an analysis that pays due consideration to the diachronic evolution of phonological processes. Moreover, my data show that the majority of speakers display both categorical allophony of light and dark variants, and gradient phonetic effects coexisting in the same grammar. Therefore, an adequate account of English /l/-darkening presupposes both a theory of the morphosyntax-phonology interface, and the phonetics-phonology interface. I interpret these results by assuming the modular architecture of the life cycle of phonological processes, whereby a phonological rule starts its life as a phonetically driven gradient process, over time stabilising into a phonological process at the phrase level, and advancing through the grammar. Not only does the life cycle make predictions about application at different levels of the grammar, it also predicts that stabilised phonological rules do not replace the phonetic processes from which they emerged, but typically coexist with them. Moreover, the obvious intimate link between /l/-darkening and /l/-vocalisation can be explained in terms of the life cycle, in the way of lenition trajectories. The results here show that, as predicted, the more recent stage of the lenition trajectory is harsher in terms of its phonetic effect, as well as less advanced in the grammar, applying at a lower level than darkening when the two co-occur in the same variety. I conclude by arguing that the proposed analysis demonstrates that a full understanding of /l/-darkening in English requires an approach that considers variation under phonetic, phonological and morphosyntactic terms. The wide range of dialectal diversity, for which this thesis provides only a small subset, shows a great deal of orderliness when paying due consideration to the diachronic evolution of variable phonological processes.

Ce travail de thèse, réalisé au Laboratoire de Physique de la MatièreCondensée (LPMC), s'inscrit dans le contexte des nouveaux lasers etamplificateurs à fibre optique opérant dans le visible. Cependant, ledéveloppement de telles fibres est limité par des phénomènes tels que le photonoircissement.Cette thèse a été consacrée à l'étude et à la résolution desproblèmes de photo-noircissement des fibres optique de silice dopées àl’aluminium et au thulium, sous pompage optique à 1,07 μm. Au cours de cettethèse, une nouvelle méthode de fabrication spécifique à nos besoins a étédéveloppée et mise en oeuvre au LPMC. Une étude systématique du rôle de laconcentration en thulium dans les mécanismes de photo-noircissement a étémenée. Le rôle du co-dopage avec de l'aluminium, du cérium ou du lanthane aaussi été analysé par des études systématiques. Le photo-noircissement estimputé à la génération de centres colorés par le pompage. Une fois créés, cescentres colorés peuvent être blanchis par la pompe. Un modèlephénoménologique sur la dynamique du photo-noircissement permet dediscuter séparément de la génération et du blanchiment. Au cours de cetravail, il a été montré que l'augmentation de la concentration en thulium et/oula puissance de pompe a pour effet d'améliorer le phénomène de génération. Àl'opposé, l'augmentation de la concentration en aluminium ou en cérium ou enlanthane a pour effet d'améliorer les mécanismes de blanchiment. La mise enévidence et la compréhension de ces mécanismes ouvrent la voie vers desnouveaux lasers et amplificateurs à fibre optique dans le domaine du visible / This thesis, conducted at the Laboratoire de Physique de la Matière Condensée(LPMC), is in the context of new lasers and optical fiber amplifiers operating inthe visible. This wavelength range is currently booming for many applications.However, the development of such fibers are limited by the photo-darkeningphenomenon. This phenomenon consists of the loss of transparency in thematerial during its use under optical pumping. This thesis is devoted to thestudy and the resolution of issues caused by photo-darkening in aluminum- andthulium-doped silica optical fibers when optically pumped at 1.07 μm. In thisthesis, a new method of fiber manufacture that is specific to our needs hasbeen developed and implemented at LPMC. A systematic study of the role ofthulium concentration in the photo-darkening mechanism was conducted. Therole of the co-doping with aluminum, cerium or lanthanum was also analyzedby systematic studies. The photo-darkening is attributed to the generation ofcolor centers by pumping. Once created, these color centers can be bleachedby the pump. A phenomenological model of the dynamics of photo-darkeningallows a separate discussion between the generation and the bleachingphenomena. In this work, it is shown that the increasing of the concentration ofthulium and/or the pump power has the effect of increasing the generationphenomenon. In opposite, increasing of the concentration of aluminum orcerium or lanthanum has the effect to intensify the bleaching mechanism. Theidentification and understanding of these mechanisms open the path to newlasers and optical fiber amplifiers in the visible range

Unconventional nanofabrication techniques; both those which have been newly developed and those under development, had brought inexpensive, facile, yet high quality means to fabricate nanostructures that have feature sizes of less than 100 nm in industry and academia. This dissertation focuses on developing unconventional fabrication techniques, building studying platforms, and studying the mechanisms behind them. The studies are divided into two main facets and four chapters. The first facet, in Chapter II and Chapter III, deals with the research and development of different nanofabrication techniques and nanostructures. These techniques include litho-synthesis, colloidal lithography, and photolithography. The nanostructures that were fabricated by these techniques include the metal nanoparticle arrays, and the self-assembled CdSe nanoring arrays. At the same time, the dissertation provides mechanisms and models to describe the physical and chemical nature of these techniques. The second area of this study, in Chapter III to Chapter V, presents the applications of these nanostructures in fundamental studies, i.e. the mechanisms of plasmon enhanced fluorescence and photo-oxidation kinetics of CdSe quantum dots, and applications such as molecular sensing and material fabrication. More specifically, these applications include tuning the optical properties of CdSe quantum dots, biomodification of CdSe quantum dots, and copper ion detection using plasmon and photo enhanced CdSe quantum dots. We have successfully accomplished our research goals in this dissertation. Firstly, we were able to tune the emission wavelength of quantum dots, blue-shifted for up to 45 nm, and their surface functionalization with photo-oxidation. A kinetic model to calculate the photo-oxidation rates was established. Secondly, we established a simple mathematical model to explain the mechanism of plasmon enhanced fluoresce of quantum dots. Our calculation and experimental data support the fluorescence resonance energy transfer (FRET) mechanism between quantum dots and the metal nanoparticles. Thirdly, we successfully pattered the CdSe quantum dots (diameter ~4 nm) into nanorings with tunable diameters and annular sizes on different substrates. We also established a physical model to quantitatively explain the mechanism with the forces that involved in the formation of the nanorings.