The Macondo 252 oil spill occurred on April 20, 2010 and persisted for 86 days. Oil spill exposed Gulf fish demonstrated reduced lymphocyte counts and increased ethoxyresorufin-O-deethylase (EROD) values. Alligator gar were exposed to 0, 0.5 and 4.0 g oil/L of tank water for 48 hours, then moved to oilree water for a 7 day recovery period. After forty-eight hours exposure, lymphocyte and hematopoietic precursor populations were significantly decreased in dose responsive by exposure to oil. Following a 7 day recovery period, lymphocyte and precursor cell numbers increased. After 48 hours exposure, tissue changes included hepatocellular vacuolization and necrosis, necrotizing pancreatitis, splenic congestion and epicarditis. This demonstrates that oil exposure negatively impacts immune cells and tissues in fish and increases their disease susceptibility. Prolonged oil exposure has the potential to dramatically impact the health status of fish populations.

Geckos can freely climb on walls and ceilings against their body weight at speed of over 1ms-1. Switching between attachment and detachment seem simple and easy for geckos, without considering the surface to be dry or wet, smooth or rough, dirty or clean. In addition, gecko can shed dirt particles during use, keeping the adhesive pads clean. Mimicking this biological system can lead to a new class of dry adhesives for various applications. However, gecko’s unique dry self-cleaning mechanism remains unknown, which impedes the development of self-cleaning dry adhesives. In this dissertation we provide new evidence and self-cleaning mechanism to explain how gecko shed particles and keep its sticky feet clean. First we studied the dynamic enhancement observed between micro-sized particles and substrate under dry and wet conditions. The adhesion force of soft (polystyrene) and hard (SiO2 and Al2O3) micro-particles on soft (polystyrene) and hard (fused silica and sapphire) substrates was measured using an atomic force microscope (AFM) with retraction (z-piezo) speed ranging over 4 orders of magnitude. The adhesion is strongly enhanced by the dynamic effect. When the retraction speeds varies from 0.02 µm/s to 156 µm/s, the adhesion force increases by 10% ~ 50% in dry nitrogen while it increases by 15%~70% in humid air. A dynamic model was developed to explain this dynamic effect, which agrees well with the experimental results. Similar dynamic enhancement was also observed in aqueous solution. The influence of dynamic factors related to the adhesion enhancement, such as particle inertia, viscoelastic deformations and crack propagation, was discussed to understand the dynamic enhancement mechanisms. Although particles show dynamic enhancement, Gecko fabrillar hair shows a totally different trend. The pull off forces of a single gecko seta and spatula was tested by AFM under different pull-off velocities. The result shows that both the spatula and the seta have a rate independent adhesion response in normal retraction, which is quite different from micro-particles. Further research indicated the shape of the contact area was a key factor to the dynamic effect. In order to verify this hypothesis, artificial gecko spatula made of glass fibers was nanofabricated by a focus ion beam (FIB) and tested by AFM. These manmade spatulae also show a rate independent adhesion response. The dynamic adhesion of a single gecko seta and spatula were simulated with finite element analysis and the results also confirm the rate independent phenomena.. In conclusion, self-cleaning is induced by dynamic effect during gecko locomotion. The relative dynamic adhesion change between particles and seta makes it possible for gecko to shed the dirt particles while walking.Finally, the fatigue property of gecko seta was examined with the atomic force microscope under cyclic attachment/detachment process, mimicking gecko running. The adhesion force versus cycles has been tested and evaluated. Fatigue mechanism of gecko seta was also analyzed based on the experimental findings.

Extensive use of the organophosphate diazinon has led to its accumulation in aquatic environments and negative effects on fish health. Most studies focus on the effects of short term exposure to high levels of organophosphate pesticides. This research was conducted to assess the effect of chronic sub-lethal exposure to 0, 0.01, and 0.1 mg/L diazinon for 15 and 30 days on blood parameters and histopathological damage in alligator gar, Atractosteus spatula. Fish exposed to either concentration were motionless, produced excess mucous, had lighter skin color, and had skin lesions. Blood indices of red blood cells, leukocytes and hematocrit values significantly decreased but there was no significant change in mean cell volume. Hemoglobin values significantly increased in fish exposed to the low dose for 15 days, but significantly decreased for the other exposure doses and times. On the contrary, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration values significantly increased in fish exposed to both concentrations and duration times. Leukocyte differentials showed significant decreases in lymphocytes with significant increases of monocytes in fish exposed to the high dose in both exposure times. The most frequent biomarker for exposure to organophosphate pesticides is the inhibition of cholinesterase (ChE). Diazinon significantly reduced plasma ChE activity in a dose-dependent manner, with 62% and 72% in the low and high concentrations for 30 days, respectively. Plasma ChE could be determined from peripheral blood samples and did not require sacrifice of the fish. Fish exposed to either diazinon concentration or duration time developed histopathological changes in skin, gills, liver, and kidney tissues. The skin lesions were on the head and body, and progressed into deep ulcerations. The histopathological changes in the liver included hepatic vacuoles, swollen hepatocytes, steatosis, aggregation of macrophages, necrosis, and hepatic fibrosis. Also, exposed fish demonstrated vacuolar degeneration in the hematopoietic tissues of the kidney. Gills showed epithelial hyperplasia in the secondary lamellae. In conclusion, long term exposure to sub-lethal concentrations of diazinon induced significant changes in hematological indices and histopathological alteration in various tissues. Plasma ChE can be used to monitor diazinon exposure in wild gar populations.

Made available in DSpace on 2016-03-15T19:42:08Z (GMT). No. of bitstreams: 1 Priscila Rosin.pdf: 6027450 bytes, checksum: a3baa27fadc149b93f60fbc4ffd38a53 (MD5) Previous issue date: 2011-06-01 / Fundação de Amparo a Pesquisa do Estado de São Paulo / Wega Nery (1912-2007) was a Brazilian artist with 60 years of artistic career and cataloged over 1000 works. In this long history, there were artistic works from different phases, which were: Academic Influences ; Formal Studies ; Drawing ; Stained Glass ; Transition and Expansion ; Imaginary Landscapes ; Mitigation . Wega began her career in 1946 with figurative works, fruits of her period of study at the School of Fine Arts, theses works brought nostalgic themes of childhood, showing the home and family environment of the artist. After designing her painting and pictorial representation and deepen the studies of painting, Wega entered in black and white world of non-referrals and non-realities, it was the phase of the ink monochrome drawings. As your freedom to represent the actual increased, the color reappeared, now in abstraction with small-format screens, even geometric drawing and palette contained, informally known as "Stained Glass". In the 60‟s and 70‟s, the gestural painting has become a tool of expression in the creation of the artist, who worked with generous flicks forming large patches of vibrant colors, made with a spatula that followed her emotional impulse, it was the phase "Imaginary Landscapes". In the mid-80‟s, due to advanced age, the artist has slowed her production, which set the phase Mitigation . During this entire period devoted to art, Wega developed her artistic language and won national and international recognition. The "Portraits" were also important works that have appeared in most Wega pictorial phases / Wega Nery (1912-2007) foi uma artista plástica brasileira com trajetória de 60 anos de carreira artística e mais de 1000 trabalhos catalogados. Nessa longa trajetória, surgiram trabalhos artísticos de diferentes fases, sendo elas: Influências Acadêmicas ; Estudos Formais ; Desenhos ; Vitrais ; Transição e Expansão ; Paisagens Imaginárias e Suavização . Wega iniciou sua carreira, em 1946, com obras figurativas, frutos de seu período de estudo na Escola de Belas Artes, que traziam temas nostálgicos da infância, evidenciando ambientes domésticos e familiares da artista. Após estruturar sua pintura e representação pictórica e se aprofundar nos estudos da pintura, Wega adentrou no mundo preto e branco das não-referências e não-realidades, foi a fase dos desenhos monocromáticos a nanquim. À medida que sua liberdade de representar o real aumentava, a cor ressurgia, agora na abstração com telas de pequenos formatos, desenho ainda geométrico e paleta contida, informalmente conhecidas como Vitrais . Nos anos 60 e 70, a pintura gestual tornou-se um instrumento de expressão na criação da artista, que trabalhava com pinceladas generosas formando largas manchas de cores vibrantes, feitas com uma espátula que seguia seu impulso emotivo, era a fase Paisagens Imaginárias . Em meados dos anos 80, devido à idade avançada, a artista desacelerou sua produção, o que configurou a fase Suavização . Durante todo esse período de dedicação à arte, Wega desenvolveu sua linguagem artística e conquistou reconhecimento nacional e internacional. Os Retratos também foram obras importantes, que apareceram na maioria das fases pictóricas de Wega

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