Contaminated sediments pose a direct risk to sediment fauna and have the potential to affect other benthic assemblages. Disturbances that resuspend and remobilise contaminants may impact on filter-feeding, hard-substrate organisms that live immediately above sediments. This thesis uses laboratory and field manipulations to examine the impact of metal-contaminated sediments on sediment fauna and hard-substrate fauna simultaneously. It also compares the response of assemblages to metal contamination in a temperate and polar ecosystem. Simulated resuspension exposures in the laboratory indicated that contaminated sediments have the potential to affect hard-substrate organisms. Spirorbid polychaetes responded to both aqueous metals and to resuspended, particulate-bound metals. Impacts on hard-substrate fauna were however, not observed in manipulative field experiments using metal-spiked sediments. The recruitment and cover of hard-substrate organisms were either not affected or enhanced above contaminated sediments. In contrast, metal contamination had direct negative effects on sediment fauna, with a reduction in the abundance of most taxa. Results suggest that sediment fauna may interact with hard-substrate fauna through physical and/or biological mechanisms. In a reciprocal transplant experiment, established Antarctic hard-substrate assemblages were also unaffected by contaminant concentrations at an impacted site. Overall, metal-contaminated sediments are unlikely to pose as serious a threat to hard-substrate fauna as they do to sediment fauna. Contaminated sediments are not restricted to industrialised regions, and human activities in Antarctica have resulted in localised contamination near research stations. Although Antarctic assemblages are thought to be more sensitive than temperate assemblages to contaminants, few studies have explicitly examined this. Little evidence was found to support the theory that Antarctic assemblages are more susceptible to contaminated sediments. The response of Antarctic and temperate assemblages in the field to metal-contaminated sediments over a 10-11 month period was comparable. Responses were of a similar magnitude, despite differences in the composition of assemblages. In 10-d toxicity tests, the mortality of a common Antarctic hard-substrate organism was relatively insensitive to aqueous Cu, Zn and Pb. These results suggest that using current sediment quality guidelines from Australia may be a useful screening tool to assess the risk associated with contaminated sediments in Antarctica.

There is little published information on the distribution, abundance, seasonality and ecological roles of benthic algae on the Great Barrier Reef, although they are of fundamental importance in the ecology of coral reef communities. This study sought to provide information on algal community dynamics in two contrasting reef-flat zones: the live coral and algal turf-dominated outer flat, and the fleshy macroalgaldominated inner flat, at Heron Reef, Great Barrier Reef, Queensland, Australia.Algal community structure on dead coral limestone was studied on the inner and outer reef flat over a three-year period (from May 1986 to February 1989), and algal transplant and grazer exclusion experiments were carried out to determine the role of grazers in producing and maintaining community structure.Changes during ecological succession provide useful information about structuring processes in natural communities. Algal succession was studied using artificial substratum (concrete), because it provided a flat surface which offered logistical advantages over naturally contoured coral substratum, and because previous studies had found that artificial substrata adequately mimicked natural surfaces in marine successional studies. Succession on natural substratum was also studied for comparison, using coral clumps which had died after a bleaching episode in February 1987. The effects of season on algal succession, were investigated using four series of concrete settlement blocks, started in February, May, August and November 1986. The effect of habitat complexity on succession was examined by comparing succession on an exposed concrete surface with succession on a protected concrete surface provided with crevices. Each successional study lasted two years. Cover data for all algal species present on each sample were obtained using a sampling grid of sixty points, and these data were analysed using the non-parametric multivariate analysis program, PRIMER.A total of 105 algal taxa were identified in this study, with 101 of these recorded in the natural reef flat algal community over the three-year period. Fleshy macroalgae were the dominant group on the inner flat (56% cover), and filamentous turf algae iv were dominant on the outer flat (47% cover). The importance of water temperature and grazing intensity in producing the differences in distribution of these two groups of algae on the reef-flat were considered. Temperature was rejected as a factor, because there was virtually no temperature difference between the two sites over a two-year period. Grazing was found to be an important factor, based on a much higher rate of damage to algal transplants on the outer flat than on the inner flat; and on the development of higher algal biomass on caged than on uncaged concrete settlement blocks.Between 58 and 69 algal taxa were recorded in each of the four successional studies on exposed concrete, 78 taxa were recorded on protected concrete, and 85 taxa were recorded on bleached coral. Algal successional trajectories were similar on concrete and on bleached coral, but the rate varied substantially. Succession was fastest on bleached coral, slowest on exposed concrete, and intermediate on protected concrete. On all substrata, at both sites, early dominance by green and brown filamentous algae decreased over time, while the abundance of other forms increased. Dominance in terms of cover by early successional algae (in particular Ectocarpus) was prolonged on concrete in comparison to bleached coral, and this effect was stronger on exposed concrete than on protected concrete.It is hypothesised that inhibition of algal community development on concrete because of a relatively dense growth of early successional algae was due to one or both of two factors: 1. Reduced algal recruitment due to a lower level of substratum heterogeneity; and 2. Reduced grazing by the dominant herbivores in the system, parrotfish (Family Scaridae), because of the hardness of concrete.Succession was faster on the outer flat than on the inner flat. On bleached coral, succession to a community similar to the natural background algal community took between three and nine months on the outer flat, and between one and two years on the inner flat.There was no regular seasonal pattern of change in the reef flat algal community over a three-year period, but during early succession, algal community structure was v strongly influenced by season of initial exposure of the concrete settlement blocks. However, this variability did not persist, and by two years all seasonal series of blocks had similar communities. Six species of algae were fertile within 10 days of establishment, including the common early successional algae Ectocarpus, Enteromorpha and Polysiphonia, illustrating the potential of these species for rapid exploitation of available space.The results of this study provide much needed baseline data on algal community dynamics on the southern Great Barrier Reef, and on succession and community development following a bleaching episode. Given the rapid and dense colonisation of bare substratum by algae, and the very low rate of recruitment by corals, it seems that corals will be at a disadvantage in maintaining their abundance in this reef flat environment if coral bleaching becomes a regular event.

Diss. (sammanfattning) Umeå : Umeå universitet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 5 uppsatser.

Dissertation (Ph.D.) -- University of Texas Southwestern Medical Center at Dallas, 2008. / Vita. Bibliography: p. 120-129.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 122-136).

Orientador: Luiz de Souza Corrêa / Banca: Francisco Maximino Fernandes / Banca: Silvia Correa Santos / Resumo: O maracujá-doce é a segunda espécie de maracujazeiro mais plantada no Brasil. O maracujazeiro doce tem como vantagem sua resistência à morte prematura. Este trabalho teve como objetivo avaliar a calagem, o cultivo orgânico e mineral, na fase de formação de mudas de maracujazeiro doce (Passiflora alata Ait.) bem como no desenvolvimento destas mudas no campo. O experimento foi desenvolvido e conduzido no viveiro e no campo da Fazenda de Ensino Pesquisa e Extensão no município de Selvíria-MS. No viveiro, o experimento foi em blocos ao acaso, com oito tratamentos (adubações mineral , orgânica e calcário), quatro repetições e oito mudas úteis por parcela e no campo delineamento foi em blocos ao acaso, com oito tratamentos, três repetições e duas plantas por repetição. Foram avaliados no viveiro, a porcentagem de germinação, número de folhas, altura da planta, comprimento radicular, massa da matéria seca da parte aérea e massa da matéria seca das raízes. Na análise química foram determinadas as concentrações de macronutrientes (N, P, K, S, Ca e Mg) e de micronutrientes (Zn, Mn, Cu, Fe e B) na parte aérea e na raiz. No campo foram avaliados o diâmetro do tronco e a altura da planta. Com base nos resultados obtidos nas condições do experimento conclui-se que: Experimento no Viveiro: a) a adição de esterco bovino no substrato propiciou mudas com maior qualidade, especialmente se acompanhada de adubação mineral; b) O substrato com os tratamentos 8 (SFS + FTE-BR12 + esterco bovino + calcário), 4 (SFS + FTE-BR12 + esterco bovino) e 2 (esterco bovino) propiciou maior desenvolvimento das mudas; c) As melhores concentrações de nutrientes na massa seca da parte aérea e na raiz foram as obtidas no tratamento 8 (SFS + FTE-BR12 + esterco bovino + calcário) resultando em mudas vigorosas de maracujá doce. Experimento no Campo: d)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The sweet passion fruit is the second most planted in Brazil. The sweet passion fruit has the advantage of its resistance to premature death. This study aimed to evaluate the liming, organic farming and mineral during the formation of sweet passion fruit (Passiflora alata Ait.) As well as the development of these seedlings in the field. The experiment was conducted in the nursery in the farm of instruction, research and extension in Selviria-MS. The design was randomized blocks with eight treatments ( mineral fertilizer, lime and organic), four repetitions and eight plants useful per parcel and field design was a randomized block with eight treatments, three replications and two plants per replicate . Was evaluated in the nursery germination percentage, leaf number, plant height and root length, dry matter and shoot dry mass of roots. In the chemical analysis were determined the concentrations of macronutrients (N, P, K, S, Ca and Mg) and micronutrients (Zn, Mn, Cu, Fe and B) in shoots and roots. In the field was evaluated for plant height and trunk diameter. Based on the results obtained in the experiment can be concluded that: Experiment in the Nursery: a) the addition of manure in the substrate provided with the best quality seedlings, especially if accompanied by mineral fertilizer b) The substrate with the treatments 8 ( SFS + FTE-BR12 + manure + lime), 4 (SFS + + FTE BR12-manure) and 2 (manure) causes greater development of the seedlings; c) the best nutrient concentrations in shoot dry mass and root treatment was 8 (SPS + FTE-BR12 + manure + lime) to produce vigorous seedlings of sweet passion. Field experiment: d) Association of organic manure (farmyard manure), mineral fertilizer or lime in the substrate was positive for growth and development of plants in the field / Mestre

The fluorinase enzyme, originally isolated from Streptomyces cattleya, has the unique ability to generate a C–F bond from aqueous fluoride ion and S-adenosylmethionine, making the fluorinase an attractive biochemical tool for radiolabelling biomolecules with fluorine-18 for application to positron emission tomography (PET). The inherent substrate specificity of the enzyme is, however, limiting, as only small modifications to the natural nucleoside substrate were known to be tolerated. This thesis describes an exploration and expansion of the substrate scope of the fluorinase enzyme, and its application to radiolabelling biomolecules for PET. The design and synthesis of a novel acetylene bearing substrate for the fluorinase, 5'-chloro-5'-deoxy-2-ethynyladenosine (ClDEA) is described. ClDEA proved an excellent substrate for the fluorinase, and the kinetics of the transformation and binding affinities of the new substrate and product were investigated. The fluorinated acetylenic product was demonstrated to undergo a copper-catalysed azide-alkyne cycloaddition (CuAAC) reaction with an azide bearing RGD peptide, and this methodology was investigated for the synthesis of a novel fluorine-18-bearing prosthetic group for the synthesis of a radiolabelled RGD peptide, which was assessed in vivo in a rat. After the demonstration that the fluorinase can be used for “last step” radiolabelling of bioactive peptides, the synthesis of dimeric and tetrameric RGD-bearing substrates for the fluorinase was investigated. These large constructs underwent efficient enzymatic fluorination, and the fluorinated products showed increased binding affinity to their targets, compared to monomeric analogues. The challenges encountered during radiolabelling of these multimers with fluorine-18 using the fluorinase are discussed. A difluoromethyl-bearing nucleoside substrate (F₂DA) was synthesised as a potential substrate in the reverse direction for the fluorinase, to further probe the substrate specificity if the fluorinase. Upon incubation with the enzyme, F₂DA did not appear to undergo reaction, despite the demonstration that F₂DA binds to the enzyme. Finally, the optimisation of a fluorinase-based protocol for the synthesis of the PET radiotracer [¹⁸F]fluoroacetate is described. The enzymatic method proved unsuitable for a small animal study due to contamination of the final product, and a chemical method was investigated and optimised as an alternative approach. [¹⁸F]Fluoroacetate synthesised using the developed chemical method was employed in an in vivo evaluation of acetyl CoA synthetase (ACSS2) activity in healthy and tumour-bearing mouse models, in an study to assess the activity of ACSS2 in breast and colon cancer models in mice.

Dans les dispositifs électronique, il est prochainement attendu que la réduction de la taille des composant atteingne prochainement la limite quantique. De ce fait, manipuler l'information quantique apparait comme un nouveau challenge. Les Qubits supraconducteurs basé sur la physique du solide et les Jonctions Josephson sont des systèmes prometteurs qui profitent des avantage des technologies de la micro-électronique. Toutefois, le temps de décohérence des états quantique est encore un facteur limitant. Cette limitation est généralement attribuée à la faible qualité cristalline des matériaux utilisés (défauts cristallins, impuretés). La technique d'épitaxie par jets moléculaires a été utilisé pour la croissance de couches minces de rhénium de haute qualité cristalline sur des substrat de saphir dans un environnement Ultra Haut Vide. Le misfit existant entre les réseaux cristallins du rhénium et du saphir est suffisamment bas pour permettre une croissance épitaxiale du rhénium sur le saphir, mais également une croissance d'une barrière tunnel en oxyde d'aluminium monocristallin sur la couche de rhénium elle-même. Afin d'améliorer la qualité cristallographique de la couche de rhénium, des simulations et de nombreuses techniques de caractérisation ont été utilisées. Puis les propriétés supraconductrices des films de rhénium ont été étudié à des températures ultra basses afin de comparer ces propriétés à la qualité cristallographique de nos films. / In electronic devices, it is expected that the quantum limit will soon be reached with decreasing system size. Therefore, manipulating quantum information appears as a new challenge. Solid state Qubits based on superconducting Josephson junction are promising systems which take advantage of microelectronics technology. However, decoherence time of the quantum states is still a limiting factor. This has been generally ascribed to the poor crystallographic quality of the materials used so far (crystallographic defects, impurities). The Molecular Beam Epitaxy (MBE) technique may be used to grow rhenium (Re) films of high quality on sapphire substrates in an Ultra High Vacuum (UHV) environment. So far, the misfit between Re and sapphire is low enough to permit the growth of a single crystal aluminium oxide thin film on top of the Re layer. In order to improve the crystallographic quality of the Re film, some simulations and several characterizations techniques have been used. Then, the superconducting properties of rhenium films have been studied at Ultra Low Temperature in order to compare with their crystallographic qualities.