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Síntese do feromônio sexual e respostas eletrofisiológicas frente ao óleo essencial de Psidium guajava de Tryrinteina arnobia
(Universidade Federal de São Carlos, 2008-09-16) Neppe, Tiago; Corrêa, Arlene Gonçalves; https://lattes.cnpq.br/7425467156776144; https://lattes.cnpq.br/7612655561022749
The study of semiochemicals involves the knowledge of different interaction levels between organisms and allows us to understand communication mechanisms and the action of specific compounds in the insect behavior. The eucalyptus-brown-looper, Thyrinteina arnobia (Stoll, 1782) (Lepidoptera: Geometridae) is considered an important pest in Brazil for native plants, as Psidium guajava, and exotic plants, as for example Eucalyptus species. This work describes the racemic synthesis of T. arnobia sex pheromone, 3,4-epoxy-6,9-heneicodiene, in 11 steps and 27% overall yield. The synthesized compound, tested by electroantennography (EAG) with male and female antennae at concentration of 100mg/mL, demonstrated identical bioactivity for both sex. We also obtained essential oils from leaves of wild white guava (P. guajava), by steam distillation, in order to investigate its electrophysiological action in T. arnobia. It was observed that the composition of young and old leaves of guava is different. Nevertheless, the EAG essential oil analyzes towards male and female antennae have shown that they are very bioactive. The synthetic pheromone and the kairomones isolated from the essential oil may allow us to understand the action of these substances in the insect behavior, through laboratory and field tests observation. Confirmed the substances attractive actions, their use in pest management will become very important.
Caracterização elétrica de eletrólitos baseados em céria Nano e microcristalinos para pilhas a combustível
(Universidade Federal de São Carlos, 2008-09-16) Lapa, Camila Maria; Souza, Dulcina Maria Pinatti Ferreira de; https://lattes.cnpq.br/4100119317525940; https://lattes.cnpq.br/3459145799593883
Fuel cells are considered the most promising way for generating electrical energy in a near future. The economic fuel cells viability is directly related to the reduction of its operating temperature which is related to the properties of the electrolyte. In this work ceramic nanopowders of Ce0.8Y0.2O1.9 e Ce0.8Gd0.2O1.9 obtained by chemical synthesis were sintered through two-step sintering to obtain dense bodies with submicormetric grain size, in order to improve the grain boundary electrical conductivity of ceria-based electrolytes. Grain and grian boundary conductivities are dependent on grain size besides sintering schedule. The formation of secondary phases indicates that the improvement in grain boundary conductivity is related to the microdomains dynamics in microstructure. Ga2O3 addition was not effective in the densification of Ce0.8Y0.2O1.9 e Ce0.8Gd0.2O1.9 ceramics and it was deleterious to grain boundary conductivity, although it improved grain conductivity comparing to Ga2O3 free samples. An alternative to improve the electrical conductivity of ceria-based electrolytes is the formation of nanometric doped ceria amorphous carbonate composites. The composites were characterized and the components were set in different arrangements to evaluate the existence of interfacial effedt between the phases. The electrical characterization of these sets does not indicate the existence of this interfacial effect.