Cette thèse rapporte trois modes d'activation complémentaires pour la génération de radicaux à base de phosphore, qui ont été utilisés pour la synthèse de composés organophosphorés.Tout d’abord, nous avons décrit une génération photocatalytique de radicaux phosphinoyle en utilisant le sel d'acridinium, le perchlorate de 9-mésityl-10-méthylacridinium connu sous le nom de catalyseur de Fukuzumi, en tant que photocatalyseur, et triflate de diphényliodonium comme photo-oxydant externe. Ce système purement organique nous a permis d'obtenir la première hydrophosphinylation sans métal des alcènes. Plusieurs enquêtes mécaniques, telles que la résonance paramagnétique électronique (EPR), la photolyse laser, la fluorescence et les quantum yields measurements ont été utilisées pour comprendre les facteurs qui régissent cette photoréaction.Dans le chapitre suivant, la formation de complexes Electron-Donor-Acceptor (EDA) entre les oxydes de phosphine secondaires et l'ion diphényliodonium a été utilisée pour générer un radical phosphinoyle sous irradiation bleue. Des études expérimentales et théoriques combinées ont été utilisées pour élucider la formation de complexes d'EDA. Cette stratégie a ensuite été utilisée pour décrire l'hydrophosphinylation des alcènes.Le dernier chapitre rapporte une méthode légère sans métal pour la synthèse d'oxindoles phosphorylés, qui sont des composés pharmaceutiques potentiellement actifs. La portée et les limites de cette approche ont été discutées avec des enquêtes mécanistiques préliminaires. / This Thesis reports three complimentary modes of activation for the generation of phosphorus based radicals, which have been employed for the synthesis of organophosphorus compounds.We have first described a photocatalytic generation phosphinoyl radicals by using the acridinium salt, 9-mesityl-10-methylacridinium perchlorate known as Fukuzumi’ catalyst, as a photocatalyst and diphenyliodonium triflate as an external photooxidant. This purely organic system allowed us to achieve the first metal–free hydrophosphinylation of alkenes. Several mechanistic investigations, such as Electron Paramagnetic Resonance (EPR), Laser Flash Photolysis, fluorescence quenching and quantum yields measurements have been employed to understand factors governing this photoreaction.In the subsequent chapter, the formation of Electron–Donor–Acceptor complexes (EDA) between secondary phosphine oxides and the diphenyliodonium ion has been used to generate phosphinoyl radical under blue irradiation. A combined experimental and theoretical investigations have been used to elucidate the formation of EDA complexes. This strategy has then been employed to describe hydrophosphinylation of alkenes.The last chapter reports a metal–free visible light mild method for the synthesis of phosphorylated oxindoles, which are potentially active pharmaceutical compounds. Scope and limitations of this approach have been discussed along with preliminary mechanistic investigations.

The PhD thesis deals mainly with the coloration (and also scalation) of selected reptile species and explores evolutionary or ecological contexts indicated by these traits. The main topics can be roughly divided into two groups: 'antipredation signals' and 'effects of parthenogenesis'. The dominant method used in most studies is visual modelling. The work consists of the following case studies. 1) Blue-tongue skinks use their conspicuous blue tongues to threaten potential predators. We found that the tongue has a relatively high UV reflectance, a typical feature of intraspecific communication in lizards. Using visual models, we investigated how the blue tongue is perceived by the conspecifics and predators (birds of prey). In both visual models, the UV-blue tongue appears more conspicuous against the natural background than a pink tongue. In addition, in the conspecifics model, its hue partially overlaps with hues of UV-blue spots, which are sexually selected traits in various species of lizards. Thus, the UV-blue tongue seems to contribute to the effectiveness of the deimatic display and its possible role in intraspecific communication cannot be ruled out either. 2) We detected UV reflectance in non-pigmented areas of the skin in the Leopard gecko (Eublepharis macularius). These form white patches...

This Licentiate thesis presents research accomplished at theSection of Atomic and Molecular Physics at the Royal Instituteof Technology in Stockholm using photon induced fluorescencespectroscopy (PIFS) during the last two years. The main results presented are summarized: - Neutral photodissociation in CO was observed aftersynchrotron photon excitation in the range 19-26 eV bycollecting dispersed fluorescence from excited neutral C atoms.Follow-up ab initio calculations point out CO Rydberg seriesconverging to the CO+ C and D states as precursors. - The branching ratio between N2 + (B-X)(v’=1,v’’=2) and (v’=0,v’’=1)transitions in the 20-46 eV energy range reveals strongnon-Franck-Condon effects. Ab initio calculations indicate thatthe autoionization of certain superexcited states areresponsible for some of the structures present in the branchingratio curve, confirming the important role of non-Rydbergdoubly excited resonant states (NRDERS) in de-excitationprocesses above the ionization potential. - Photon induced neutral dissociation processes in NO arereported. Neither Rydberg series nor other molecular states inNO known so far can account for the collected data. From abinitio calculations more information regarding the NO precursorstates and the mechanism behind the observed neutraldissociation were obtained. - The details of a new experimental set-up for gas phasefluorescence measurements using synchrotron radiation aredescribed. It is able to perform simultaneous measurements ofdispersed and total fluorescence in the visible range. Thefirst results obtained with this set-up are presented,concerning fluorescence after excitation of the N2 molecules inthe N 1s edge. These four studies conform the set of papers enclosed in theLicentiate thesis. Finally a pre-study to further apply PIFS to speciespreviously excited by microwave discharge is included as futureplans. / NR 20140805

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<p> UV radiation disinfection technology is an advantageous method of wastewater disinfection as it avoids the formation of chemical by-products typically found from chlorination. One challenge with this technology is avoiding fouling on the quartz sleeves in which the UV lamps are housed. In this study, using a model fouling system, the roles in fouling of light, and the constitution of the fouling media, are examined. The systematic determination of fouling by various mixtures of human serum albumin, humic acid, Ca^2+, and Fe^3+ was carried out on quartz slides in the presence and absence of UV (254nm) light. Fouling was assessed by the reduction in transmission of UV light through the quartz slides over time. It was determined that the most important factors were the concentration of..iron and protein, which apparently act synergistically to foul the surface. Other contributing factors to the magnitude of fouling include the flow rate and the age of the fouling solution. Most important was the presence of UV light. In all solutions examined, fouling was observed to a lower degree when the system was exposed to light. On the other hand, XPS analysis has demonstrated differences in the nature of the fouling layer on the surface exposed to UV light compared to that in the dark. </p> <p> It is generally accepted that low energy surfaces are less easily fouled than polar surfaces. Therefore, hydrophobic modification of the quartz by a series of different silane coupling agents was undertaken. Irrespective of the nature of the coating (alkylamine, alkyl, aryl, fluorocarbon, silicone), the rate and magnitude of fouling on the surface were comparable to the unmodified quartz. However, the more hydrophobic surfaces were easier to clean. </p> / Thesis / Master of Science (MSc)

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Plants have evolved multiple surveillance mechanisms to detect the presence of disease-causing organisms. One mode of surveillance is based on dozens of constitutively expressed resistance (R) genes. R genes recognize pathogen gene products as signals of invasion. We are interested in how plants evolve R genes to keep pace with rapidly evolving pathogen populations. The mechanisms that drive the evolution of new R genes are poorly understood. There is data that supports the relevance of recombination in the evolution of resistance gene clusters in plants. However, a more comprehensive understanding of the molecular biology of recombination and the impact recombination has on R gene evolution is necessary. The objectives of this dissertation were to develop a genetic screen that models meiotic unequal crossing over at a synthetic RPP8 (synthRPP8) resistance gene cluster and to assess the effect of abiotic stress on recombination with the synthetic RBCSB gene cluster (synthRBCSB) in Arabidopsis. The genetic screen utilized in these studies specifically identifies a novel recombinant gene and a concomitant gene duplication that results from meiotic unequal crossing-over by coupling chimeric gene formation to the activation of the firefly luciferase gene. Two synthRPP8 clusters were constructed and extensive optimization of screening conditions were performed. An initial screen of ~1 million synthRPP8 transgenic plants was performed and plants that expressed the luc+ phenotype were isolated and analyzed. Unexpectedly, background bioluminescence was found to interfere with the identification of bona fide luc+ synthRPP8 recombinants. An abiotic stress response assay was performed and the data suggests activation of a putative stress response element in the promoter of RPP8 is responsible for background levels of in vivo luciferase activity. The background bioluminescence could not be sufficiently reduced. Therefore, two additional synthRPP8 constructs, synthRPP8-3 and synthRPP8-4, were constructed and are currently being examined for their utility to model meiotic unequal crossing-over. UV-C treatment was shown to stimulate somatic unequal crossing over, as well as upregulate defense/stress response genes and transcription factors. Meiotic recombination may also be affected by stress. Therefore, the effect of UV-C irradiation on the frequency of unequal meiotic recombination between paralogous RBCSB genes and on the expression of genes associated with the defense/stress response was examined. We observed a ~2-fold increase in the frequency of meiotic recombination after UV-C irradiation but this increase was not statistically significant. We did not detect a significant alteration in the steady-state MYB10, PR-1 and HSF-3 mRNA levels by semi-quantitative RT-PCR. The expression data we gathered provided minimal support for whether the UV-C treatment was an effective DNA damaging agent. / Ph. D.