The effect of ethanol on the stress response in rats was examined. Experimental animals were given 0.25 ml of 28 percent ethanol or 0.25 ml of water orally once a day, five days a week, for a period of twelve months and were then subjected to fifteen minute cold stress. Corticosterone levels in ethanol-treated males following stress were significantly lower (22 percent) than in the sham group. Adrenal weights in sham-treated females were significantly higher (15 percent) than in the ethanol group at the end of twelve months. Mortality in sham-treated males was significantly higher (60 percent) than in ethanol-treated males. The effects observed may be due to the sedative action of ethanol on cortical centers controlling the hypothalmus.

Der Neurotransmitter Serotonin spielt ein Rolle bei der Entwicklung von Ethanoltoleranz und Alkoholismus. Die vorliegende Arbeit untersuchte die Funktion von Serotonin (5HT) im Bezug auf Ethanolsensitivität und Toleranz in Drosophila melanogaster. Pharmakologisch wurden die 5HT Konzentrationen durch Füttern eines Vorläufers der 5HT Synthese kurzeitig erhöht oder mit einem Syntheseinhibitor reduziert. Die Veränderung der 5HT Konzentrationen mittels dieser Pharmaka hatte jedoch keinen Einfluss auf die Entwicklung von Ethanolsensitivität oder Toleranz. 5HT wird durch den 5HT Transporter (SERT) aus dem synaptischen Spalt in die Präsynapse wieder aufgenommen. Die kurzzeitige Fütterung des SERT Inhibitors Paroxetin führt zu erhöhter Ethanolsensitivität und reduzierter Toleranz. Ein ähnlicher Phänotyp wurde in der hypomorphen sert55 Mutante, die eine reduzierte dsert Expression aufweist, beobachtet. Dies legt nahe, dass kurz- wie langfristige Reduktion der SERT Funktion die Entwicklung einer vollständigen Ethanoltoleranz verhindern. Folglich hat die Verlängerung der 5HT Signaltransduktion im synaptischen Spalt, nicht aber die allgemeine Erhöhung von 5HT Konzentrationen im Fliegengehirn einen Einfluss auf die Entwicklung von Ethanoltoleranz. Zur genauen Bestimmung der SERT Expression im adulten Gehirn der Fliege wurde ein Drosophila SERT (dSERT) Antikörper hergestellt. Mit Hilfe dieses Antikörpers konnte gezeigt werden, dass der dSERT mit serotonergen Somata, Axonen und Dendriten kolokalisiert. Ferner sollten 5HT Konzentrationen im synaptischen Spalt durch Überexpression des wildtypischen dsert in einem Großteil der Neurone mit Hilfe des UAS/GAL4 Systems reduziert werden. Diese Fliegen wiesen weder eine veränderte 5HT Konzentration in den Köpfen auf noch war die Ethanolsensitivität bzw. Toleranz verändert. Das kann einerseits daran liegen, dass der dSERT nicht in die Membran integriert wird oder andererseits daran, dass unser Konstrukt nicht funktional ist. Die Überexpression eines inaktiven dSERTs sollte theoretisch zur Erhöhung von 5HT Konzentrationen im synaptischen Spalt führen. Wurde ein inaktiver dSERT in den meisten Neuronen der Fliege exprimiert, erhöhten sich zwar die 5HT Konzentrationen in den Köpfen der Fliegen, dennoch war das ethanolinduzierte Verhalten nicht verändert. Zusätzlich wurde untersucht, welchen Einfluss die Inhibition der 5HT Ausschüttung auf die Entwicklung von Ethanolsensitivität und Toleranz hat. Zur Inhibition der Neurotransmission in serotonergen Zellen wurde ein Tetanus Toxin (TNT) Transgen in Verbindung mit verschiedenen GAL4 Treiberlinien eingesetzt. Die Inhibition von serotonergen und dopaminergen Neuronen mit Hilfe einer GAL4 Linie, die einen Abschnitt des Gens der Dopamin Decarboxylase (ddc) beinhaltet, führte zu keiner Veränderung von Ethanolsensitivität bzw. Toleranz. Für weitere GAL4 Linien wurde zunächst das Expressionsmuster neuroanatomisch untersucht. Von vier ausgewählten GAL4 Linien zeigten zwei Expression in serotonergen Neuronen. Die sert1+2-GAL4 Linie mit einem Stück Promotorregion des dsert zeigt Expression in 46% der serotonergen Neuronen. Wurden diese mit Hilfe von Tetanus Toxin inhibiert, zeigten die Fliegen eine leicht aber signifikant erhöhte Ethanolsensitivität und eine unveränderte Toleranz. Die zweite GAL4 Linie enthält ein Stück Promotorregion des 5HT1b Rezeptors und zeigt Expression in ebenfalls 46% der serotonergen Neurone, weitgehend überlappend mit der Expression der Linie sert1+2-GAL4. Jedoch exprimiert die 5htr1b-GAL4 Linie zusätzlich in vier serotonergen Neuronen, in elf dopaminergen und einem unbekannten Neuron. Interessanterweise ist nach Inhibition der Neurotransmission in diesen Neuronen eine stark erhöhte Ethanolsensitivität sowie eine reduzierte Ethanoltoleranz zu beobachten. Folglich könnte die Inhibition der Neurotransmission in dopaminergen Neuronen für die Reduktion der Ethanolsensitivität verantwortlich sein. Deshalb wurde die Neurotransmitteraussschüttung in dopaminergen Neuronen mit Hilfe der th-GAL4 Linie und TNT unterdrückt und diese Fliegen wurden auf ihre Fähigkeit untersucht, Ethanolsensitivtät und/oder Toleranz zu entwickeln. Nach Inhibition der von th-GAL4 getriebenen dopaminergen Neurone wurde eine erhöhte Ethanolsensitivität gemessen, aber keine signifikant veränderte Ethanoltoleranz. Da die ddc-GAL4 Linie im Vorfeld keinen ethanolinduzierten Verhaltensphänotyp gezeigt hat, sollte bestimmt werden, welche dopaminergen Neuronen der 5htr1b-GAL4 sowie der th-GAL4 Linie für die erhöhte Ethanolsensitivität verantwortlich sind. Serotonerge Neuronengruppen, die in die Entwicklung von Ethanolsensitivität und Toleranz involviert sein könnten, sind SE1, SE2, SE3, LP1, LP2, SP1, SP2 und IP, während es sich bei den dopaminergen Neuronengruppen um PAL1, PPL1, PPM2, PPM3 und SVP1 handeln könnte. Einige Neurone der 5htr1b-GAL4 Linie projizieren in den Ellipsoidkörper, eine Struktur des Zentralkomplexes, für die bereits gezeigt wurde, dass sie in die Entwicklung vonEthanoltoleranz involviert ist. Jedoch muss näher untersucht werden, welche Neuronen für die Innervation verantwortlich sind. Dafür sollten GAL4 Linien verwendet werden, die eine ähnliche Expression wie die 5htr1b-GAL4 Linie, aber ausschließlich im Ellipsoidkörper, zeigen. In dieser Arbeit konnte zum ersten Mal gezeigt werden, dass serotonerge und dopaminerge Neurone in die Entwicklung von Ethanolsensitivität und Toleranz in Drosophila melanogaster involviert sind. Ferner konnte gezeigt werden, dass eine veränderte 5HT Signaltransduktion zu einer reduzierten Toleranz führt. Weiterführend ist die Identifizierung von serotonergen Neuronen, die für die Entwicklung von Ethanolsensitivität und/oder Toleranz verantwortlich sind, von großem Interesse. Ziel ist es, die neuronalen Schaltkreise aufzudecken, die den Phänomenen Ethanolsensitivität und Toleranz zugrundeliegen. / Serotonin dysregulation is strongly implicated in the development of ethanol tolerance and alcoholism. This work examined the role of the neurotransmitter 5HT in the development of ethanol sensitivity and tolerance in Drosophila melanogaster. Using a pharmacologic approach 5HT concentrations were increased after feeding a 5HT precursor or decreased after feeding a 5HT synthesis inhibitor. This change of 5HT concentrations did not influence the development of ethanol sensitivity or tolerance. Reuptake of 5HT into the pre-synapse is regulated via a 5HT transporter (SERT). After feeding the SERT reuptake inhibitor Paroxetin an increase in ethanol sensitivity and a reduction in tolerance was observed. A reduction of SERT expression in the hypomorph sert55 mutant leads to a similar phenotype. Supposing short-term as well as long-term reduction of SERT function inhibits the development of normal ethanol tolerance. Therefore, the prolonged 5HT signalling within the synaptic cleft, but not the overall raising of 5HT concentrations in fly brains has an influence on the development of ethanol tolerance. To determine the SERT expression in the adult brain of the fly, a Drosophila SERT (dSERT) antibody was generated. This antibody co-localizes with serotonergic somata, axons and dendrites. Furthermore, 5HT concentrations were reduced in the synaptic cleft, through over-expression of a wildtype dSERT in most neurons using the UAS/GAL4 system. Those flies neither showed a change in 5HT concentrations in heads, nor a changed development of ethanol sensitivity and tolerance. On the one hand this can be due to dSERT that is not integrated in the membrane of the pre-synapse or on the other hand that our construct is not functioning. Over-expression of an inactive dSERT should theoretically lead to an increased 5HT signalling in the synaptic cleft. The inactive dSERT was expressed in most neurons and increased 5HT concentrations in heads, but had no influence on ethanol induced behavior. Moreover it was investigated, what influence the inhibition of 5HT neurotransmission has on the development of ethanol sensitivity and tolerance. To inhibit the neurotransmission of serotonergic cells a tetanus toxin transgene in combination with various GAL4 driver lines was used. The inhibition of serotonergic and dopaminergic neurons using a GAL4 driver line that contains a fragment of the dopamine decarboxylase gene does not influence ethanol sensitivity, or tolerance. For additional GAL4 lines first the expression pattern was studied by neuroanatomy. Out of four selected GAL4 lines two showed expression in serotonergic neurons. The sert1+2-GAL4 line which included a fragment of the dsert promotor region shows expression in 46% of the serotonergic neurons. Inhibition of those neurons with tetanus toxin shows a slight, but significant increase in ethanol sensitivity, but normal tolerance. The second GAL4 line contains a promotor fragment of the 5HT1b receptor gene and also expresses GAL4 in 46% of the serotonergic neurons, largely overlapping with the expression pattern of the sert1+2-GAL4 line. However, the 5htr1b-GAL4 line in addition expresses GAL4 in four serotonergic, eleven dopaminergic and one unknown neuron. Interestingly, after inhibition of those neurons, increased ethanol sensitivity and reduced tolerance was observed. The inhibition of neurotransmission in those dopaminergic neurons could be responsible for increased ethanol sensitivity. In the next step, we therefore inhibited neurotransmission exclusively in dopaminergic neurons using a GAL4 line with a gen fragment of the enzyme tyrosine hydroxylase (th-GAL4) and tested those flies for ethanol sensitivity and tolerance. After inhibition of neurons driven by the th-GAL4 line increased ethanol sensitivity was measured, but normal tolerance. We wanted to find out, which dopaminergic neurons of the 5htr1b-GAL4 and the th-GAL4 line are responsible for increased ethanol sensitivity. Serotonergic groups of neurons that could be involved in the development of ethanol sensitivity and tolerance are SE1, SE2, SE3, LP1, LP2, SP1, SP2 and IP, whereas dopaminergic neurons that might play a role could belong to the groups PAL1, PPL1, PPM2, PPM3 and SVP1. Some neurons of the 5htr1b-GAL4 line project into the ellipsoid body, a structure of the central complex that was shown previously to be involved in the development of ethanol tolerance. Therefore it should be investigated which neurons are responsible for the innervation of the ellipsoid body. In this case GAL4 lines should be used, that show a similar expression pattern as our 5htr1b-GAL4 line, but exclusively express GAL4 in neurons that project into the ellipsoid body, to investigate if inhibition of a small subset of neurons influences ethanol sensitivity and/or tolerance. In this work, for the first time, the involvement of the serotonergic and dopaminergic system in the development of ethanol sensitivity and tolerance was demonstrated in the fly. Furthermore we showed that modified 5HT signalling leads to a reduced tolerance. The next step is to identify serotonergic and dopaminergic neurons that are responsible for the development of ethanol sensitivity and tolerance. Our intention is to reveal neuronal frameworks that underlie ethanol sensitivity and tolerance.

Thesis advisor: Frank Gollop / This thesis explores the unanticipated consequences of producing ethanol for use as a transportation fuel in the United States. Statistical analysis is conducted to determine the effect that increased ethanol production has on the prices of two essential American commodities: corn and gasoline. A simultaneous system of the demand and supply of corn is developed to estimate the effect of ethanol on the price of corn. The results of this model suggest that during the period 1986-2001, corn demanded for ethanol production caused the price of corn to be 19% higher than it otherwise would have been. This result is noteworthy because the majority of American foods contain some type of corn product. A second simultaneous system is developed to determine the effect of ethanol on the price of gasoline. Neither a change in the price of ethanol nor a change quantity of ethanol per gallon of gasoline was found to have a significant impact on the price of gasoline. / Thesis (BA) — Boston College, 2009. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: College Honors Program. / Discipline: Economics Honors Program. / Discipline: Economics.

The effect of the addition of ethanol (2% and 6%) during the Fischer-Tröpsch (FT) synthesis has been investigated using a 10%Co/TiO2 catalyst in a stirred basket reactor (T = 220°C, P = 8 bar, H2/CO = 2). The transformation of ethanol vapour (2% and 6% in nitrogen) over the Co/TiO2 catalyst was also studied in the absence of the synthesis gas under FT reaction conditions. Ethanol was observed to be incorporated in the growing chain and was found to (i) increase the selectivity to light products, (ii) increase the olefin to paraffin ratio and (iii) significantly decrease the catalyst activity. These effects were almost completely reversed when the ethanol in the feed was removed. Thermodynamic predictions, TPR and XRD analysis have shown that cobalt metal particles were oxidised to CoO by ethanol but that re-reduction to Co metal was possible when ethanol was removed from the feed stream allowing the catalyst to recover most of its initial performance, in particular when high flow rates were used. The effect of the cobalt carboxylate chain length (C2, C5 and C9) used in the preparation of alumina supported cobalt catalysts has been studied by TPR, XRD and hydrogen chemisorption techniques. The activity and selectivity of the prepared catalysts have been evaluated for the Fischer-Tröpsch (FT) reaction in a stirred basket reactor. It is shown that for catalysts with Co content of 10 wt.% the activity increases as the carboxylate chain length increases while the selectivity towards methane and light hydrocarbons decreases with the carboxylate chain length. The catalyst prepared using cobalt acetate was found to present the highest metal-support interaction and the poorest performance for the Fischer-Tröpsch reaction. When the metal content was increased to 15 wt.% Co and 20 wt.% Co respectively, the metal-support interaction for the catalyst prepared from cobalt acetate significantly decreased making it a better catalyst for the FT reaction compared to the catalysts prepared from C5 and C9 cobalt carboxylates. The effect of the addition of Au to a Co FT catalyst supported on titania, alumina and silica respectively, has been investigated by varying the amount of Au (0.2 to 5 wt.%) added to the catalyst. The catalysts were characterized by atomic absorption spectroscopy, XRD, XPS and TPR analysis. The catalyst evaluation for the Fischer- Tröpsch reaction activity and selectivity was achieved in a fixed bed micro-reactor (H2:CO = 2; 20 bar; 220°C). Addition of Au to supported Co catalysts improved the catalyst reduction and the cobalt dispersion on the catalyst surface. The catalyst activity for the FT reaction and the methane and light product selectivity increased with Au loading in the catalyst.

Eletrocatalisadores de Pt-Sn suportados em carbono de elevada área superficial foram preparados por redução química de precursores metálicos em solução usando como agente redutor o ácido fórmico 0,5 M, 0,1 M e 2 M e caracterizados em termos de estrutura, morfologia e propriedades superficiais para aplicação em células a combustível a etanol direto (DEFC). Os catalisadores foram caracterizados por fluorescência de raios X (XRF), difração de raios X (DRX), espectroscopia de fotoelétrons de raios X (XPS), microscopia eletrônica de transmissão (TEM) e análise termogravimétrica (TGA). Os testes eletroquímicos dos catalisadores foram realizados com o uso de medidas de polarização, voltametria cíclica e linear, testes de estabilidade a potencial constante, e espectroscopia de impedância eletroquímica. A melhor composição atômica superficial, em termos de desempenho eletroquimico foi Pt3Sn1/C. Sobrepotenciais ânodicos são necessários de modo a gerar espécies oxidadas na superfície de platina, desta maneira a reação é favorecida. Em termos de produtos de oxidação, o acetaldeído e o ácido acético foram os principais produtos detectados por HPLC, com um baixo teor de CO2. A seletividade para o ácido acético com respeito ao acetaldeído aumentou com o teor de Sn e diminuiu com a menor concentração do agente redutor utilizado na preparação do catalisador. Estudos de estabilidade com base no catalisador Pt3Sn1/C foram realizados e o efeito de diferentes procedimentos de liga/desconexão da célula investigados. Testes de 250h a 0.4V incluindo tres ciclos de liga/desconexão a 50h, 150h e 200h são apresentados. Na sequência foram analisados os materiais com testes de estabilidade contínuo de 220 h em 0,4 V com recirculação de etanol. Pode-se dizer que no caso de um procedimento contínuo o sitema é menos afetado devido a menor perda em relação a corrosão do material. Análise morfológica e estrutural pós-testes forneceram informações complementares no que diz respeito ao diagnóstico eletroquímico in-situ e sobre o mecanismo de degradação. O aspecto mais crítico em relação às perdas irrecuperáveis aparece estar relacionado com a corrosão de Sn. Com base nos resultados obtidos neste trabalho, o protocolo de liga/desconexão foi o que mais afetou o desempenho geral da célula. / Pt-Sn electrocatalysts supported on carbon having high surface area were prepared by chemical reduction of metal precursors in solution using 0.5 M, 0.1 M and 2 M formic acid. These electrocatalysts used as anode materials for direct ethanol fuel cells (DEFC), have been physico-chemically characterized in terms of structure, morphology and surface properties. The catalysts were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM) e Thermogravimetric Analysis (TGA). The electrochemical properties of such electrocatalysts were investigated by using polarization measurement, cyclic and linear voltammetry, potentiostatic lifetime tests and electrochemical impedance spectroscopy (EIS). The best composition, in terms of electrochemical performance was the Pt3Sn1/C sample. High anode overpotentials are required in order to generate oxidized species on the platinum surface, which favor the reaction is favored. Essentially, acetaldehyde and acetic acid were detected as the main reaction products, whereas, a low content of CO2 was detected. The selectivity towards acetic acid with respect to acetaldehyde increased with the increase of the Sn content and decreased by decreasing the concentration of the reducing agent used in the catalyst preparation. Stability tests of a DEFC based on a Pt3Sn1/C catalyst was studied and the effect of different cell shut-down procedures investigated. Tests of 250 h at 0.4 V cell potential which include three intermediate shut-down/start-up cycles at 50, 150 and 200 h were was analyzed. Stability tests of 220 h at 0.4 V with recirculation of ethanol were carried out. In the case of a continuous procedure the system is less affected due to the lower loss compared material. Morphological analysis of structural and post-tests provide additional information regarding the diagnosis and in-situ electrochemical effects on the mechanism of degradation. The most critical aspect in respect of irrecoverable losses appears to be related to the corrosion of Sn. Based on the results obtained in this study, the protocol of start/stop was the one that most affects the overall performance of the cell.

No presente trabalho foi proposta a construção de eletrodos de níquel e algumas ligas (Sn, Ru), assim como de materiais nanoestruturados, para a determinação de etanol em amostras de bebidas e medicamentos. Para isto, foram utilizadas técnicas como a voltametria cíclica, a cronoamperometria, a espectroscopia de impedância eletroquímica, a microscopia de força atômica e a microscopia de transmissão. O eletrodo da liga Ni-Sn foi preparado por eletrodeposição, utilizando um banho de Watts contendo 6,25 g de NiCl2.6H2O e 0,5 g de SnCl2.2H2O em 25 mL de solução aquosa. Os depósitos foram modificados com RuO2, utilizando uma solução RuCl3 0,1 M. O eletrodo da liga foi deixado na solução em banho de ultrasson e posteriormente aquecido a 400ºC em forno em presença de oxigênio, para a decomposição térmica. O Ni nanoestruturado foi preparado a partir de uma solução contendo 1,8 g NiCl2.6H2O dissolvido em 30 mL etanol, adicionando uma mistura de 3,5 g de Zn em pó e 10 mL de aminoetanol, em agitação. A separação do pó preto foi feita com uma placa magnética. Para a confecção do eletrodo foi adicionada uma alíquota 10 mL da solução contendo o pó, náfion e etanol, na superfície do eletrodo de grafite pirolítico. Os perfis voltamétricos foram analisados em meio de hidróxido de sódio 0,5 M, podendo-se assim observar as reações de oxi-redução característica do Ni, da liga Ni-Sn, da liga modificada com RuO2 e da nanoestrutura. Foi utilizado intervalo de potencial de 100 a 700 mV com velocidade de 50 mVs-1. As medidas de impedância eletroquímica foram realizadas em sistemas com etanol com o intuito único de demonstrar a presença de um loop indutivo, que pode ser associado à transformação óxido superior/óxido inferior na superfície do eletrodo. Este loop foi observado para os eletrodos de Ni e liga, não sendo muito evidente para o eletrodo modificado com RuO2. Foram realizadas medidas de AFM para a caracterização topográfica dos eletrodos, mostrando a diferença entre as superfícies, indicando que o Ni liso foi modificado com o eletrodepósito da liga Ni-Sn e que esta também foi modificada pela deposição do RuO2. A morfologia da nanoestrutura foi observada por microscopia eletrônica de transmissão, podendo observar que se obtiveram estruturas de níquel em escala nanométrica. Os eletrodos foram utilizados na determinação de etanol em meio de NaOH 0,5 mol L-2, com a construção de curvas analíticas pelo método da adição consecutiva de alíquotas de etanol, a partir de uma solução estoque. Após a curva analítica ser levantada, foram feitos os tratamentos estatísticos obtendo-se os valores para os limites de detecção e quantificação. Com o eletrodo Ni nanoestruturado obteve-se o melhor resultado sendo este empregado na determinação de etanol nas amostras de conhaque, cachaça e enxaguante bucal, utilizando a técnica de cronoamperometria. A excelente porcentagem de recuperação obtida mostrou que o efeito da matriz, nestas determinações, é praticamente desprezível, o que está de acordo com o mecanismo da reação de oxidação do etanol sobre Ni, fortemente catalisado pela superfície dos eletrodos em estudo. / This objective of this work is related to the development of nickel and some nickel-alloys electrodes, as well as some nanostructured nickel surfaces, for ethanol determinations in drinks and in pharmacological formulations. For this, some experimental techniques were employed, as cyclic voltammetry, cronoamperometry, electrochemical impedance spectroscopy, atomic force microscopy and transmission microscopy. The Ni-Sn alloy electrode was prepared by electrodeposition from a Watts bath containing 6,25 g NiCl2.6H2O and 0,5 g SnCl2.2H2O and water in order to produce 25 mL of aqueous solution. The electrodeposits were further modified with RuO2 obtained from a 0.1 mol L-1 RuCl3 solution. The Ni-Sn alloy electrode were allowed in the ruthenium solution in ultrasonic bath and further heated to 400 oC in the presence of oxygen, in order to promote the thermal decomposition of ruthenium chloride. The nanostructured Ni surface was obtained from a chemical deposition in a solution composed by 1.8 g NiCl2.6H2O dissolved in 30 mL ethanol and adding 3.5 g of powdered Zn and 10 mL of aminoethanolic solution, under mechanical stirring. The black powder precipitated was separated by a magnetic rod. In order to prepare the electrode, with such powder, a 10 mL aliquot of solution containing the Ni powder, Nafion® and ethanol were dipped in a pirolitic graphite surface and allowed to dry. The voltammetric profiles were analyzed in order to evaluate the oxireduction characteristics of Ni surfaces, as well as the Ni-Sn alloy and the RuO2 modified surfaces and the nanostructured one. A potential window between 100 and 700 mV was scanned at 50 mV s-1, in 0.5 mol L-1 NaOH electrolyte. The electrochemical impedance spectroscopy measurements were performed in electrolytes containing ethanol, in order to observe the presence of an inductive loop, which has been associated to the low/high valences Ni oxides formed during ethanol oxidation on such surfaces. This loop was quite evident in Ni surfaces but not on the surfaces modified with RuO2. AFM measurements were performed in order to obtain the topological characteristics of the surfaces, indicating the eventual alterations associated with the RuO2 modifications. The nanostructures morphology was investigated by transmission microscopy were the nanometric dimensions of Ni phases were evident. The developed electrodes were applied in ethanol determinations in 0.5 mol L-1 NaOH solutions, prepared with Milli-Q water. The successive standard additions were used to obtain an analytical plot. After the analytical plot has been obtained, statistical analyses were performed, in order to determine the detection and quantification limits, as well as the errors involved in such determinations. As the Ni nanostructured electrodes yielded the best results, it was used in the determination of ethanol in samples of cognac, \"aguardente\" (sugar cane distilled drink) and mouthwash liquids, using chronoamperometry. The excellent recoveries percentages obtained showed that the matrix effect, in such determinations, was almost depreciable. This is related with the high catalytic power of Ni surfaces towards the ethanol oxidation reaction.

Nas últimas décadas, muitos países têm visto o uso automotivo de biocombustíveis como uma contribuição para soluções importantes, como aumento da eficiência energética, da flexibilidade e da diversificação das fontes de energia disponíveis; resposta à questão de segurança energética; promoção do uso de fontes energéticas renováveis e menos agressivas ao meio ambiente, especialmente com relação à necessidade de redução dos Gases de Efeito Estufa e aproveitamento das vantagens comparativas do país, com a promoção do desenvolvimento e da exportação de novas tecnologias e produtos. O Brasil é pioneiro na produção e utilização do etanol e, aliando-se ao aquecimento do mercado interno, existe a expectativa de aumento das exportações desse combustível, mantendo o Brasil como líder no mercado internacional. Este trabalho identifica e analisa os entraves que envolvem as perspectivas de exportação de etanol brasileiro, através do estudo dos potenciais mercados, seus programas de utilização do etanol combustível e suas barreiras tarifárias e não tarifárias, como as medidas protecionistas contra produtos estrangeiros, os subsídios aos produtores domésticos e as certificações, que podem retardar o estabelecimento do etanol como commodity e, ainda, impedir o seu crescimento no comércio internacional. / In recent decades, many countries have seen the use of biofuels in light vehicles as a contribution to important steps: to increase energy efficiency and the flexibility and diversification of available energy resources; to respond to the challenge of energy security; to promote the use of renewable and less environmentally harmful energy resources, especially with regard to the need to reduce GHG emissions and exploit the countrys comparative advantages; and to promote the development and export of new technologies and products. Brazil is a pioneer in the production and use of ethanol, and in addition to the expansion of its domestic market for this fuel, exports are expected to rise, so that Brazil will retain its leading position in the international market. This study identifies and analyzes future challenges to Brazilian ethanol exports by studying potential markets, their fuel ethanol programs, their tariff and non-tariff barriers, their protectionist measures against foreign products, their subsidies for domestic producers, and their certifications, which may delay the consolidation of ethanol as a commodity and impede its growth in international trade.

Atualmente existe um grande interesse mundial na substituição de produtos obtidos a partir do petróleo para o desenvolvimento de novos materiais a partir de fontes renováveis. Neste contexto, o estudo de células a combustível (Fuel Cell) tem recebido destaque em pesquisas tecnológicas. O uso de células a combustível como membrana trocadora de prótons (PEMFC) é uma das mais promissoras. A célula a combustível é um sistema eletroquímico que transforma diretamente energia química a partir de um combustível (hidrogênio, gás natural, etanol, etc.) em energia elétrica. No entanto, as células a combustível do tipo PEM são usualmente alimentadas com hidrogênio como combustível, o qual apresenta dificuldades devido a sua produção, armazenamento e transporte. Como uma alternativa para o hidrogênio, a oxidação eletroquímica direta de moléculas orgânicas pequenas, como o etanol, tem sido amplamente investigada. Além do mais, o uso de etanol diretamente aplicado em células a combustível mostra algumas vantagens, por apresentarem na forma liquida e ter densidade de energia teórica elevada (8,0 kWh Kg-1). No entanto, o maior problema de células a combustível de etanol resulta na produção de produtos paralelos, como o ácido acético e acetaldeído como produto final, além do CO2 que é o produto da oxidação completa do álcool, diminuindo a eficiência do processo. O objetivo deste trabalho é estudar a eletro-oxidação de etanol em Pt policristalina em solução ácida usando técnica como voltametria cíclica e cronoamperometria como técnicas eletroquímicas no intervalo de temperatura de 25 à 180°C. Particularmente, o desempenho de ligas catalisadoras de Pt com outros metais (PtRh, Pt3Ru2, e PtSn) foram comparados. A dependência da temperatura com a corrente para a eletro-oxidação de etanol a partir de curvas cronoamperométricas para a Pt policristalina e ligas catalisadoras foram medidas em potencial constante de 500 e 650 mV vs EDH. Os resultados mostraram que para a liga PtSn no potencial de 500 mV a corrente em 180°C é de aproximadamente trezentas vezes maior do que a 25°C e sete vezes maior que os outros materiais à 180°C, para a reação de oxidação. A partir dos valores das correntes de cronoamperométricas foi calculado a energia de ativação aparente (Ea) para a Pt policristalina e as ligas PtRh, Pt3Ru2 e PtSn. / In the present days there is a great world interest in substituting products obtained from petroleum applied in energy conversion by developing new materials from renewable resources. In this context, the study of fuel cells has received growing attention in technology researches. The use of fuel cells such as proton exchange membrane fuel cells (PEMFC) have been shown to be one of the most promising devices. Fuel cell is an electrochemical system, which transforms directly chemical energy of a fuel (hydrogen, natural gas, ethanol, etc.) into electric energy. However, the fuel cell is based on hydrogen, which presents difficulties concerning its production, storage and transportation. As an alternative to hydrogen, the direct electrochemical oxidation of small organic molecules, such as ethanol, has been investigated widely. Moreover, the use of ethanol in a direct alcohol fuel cell shows some advantages, it is liquid and their theoretical mass energy density is rather high (8,0 kWh Kg-1). However, the major problem of direct ethanol fuel cell results in acetic acid and acetaldehyde as an -end-product?, which competes with complete oxidation of the alcohol to CO2, decreasing the efficiency of the latter process. Based on these observations, the aim of this work is the study of the electro-oxidation of ethanol on polycrystalline Pt in acid solution using cyclic voltammetry and chronoamperometry as techniques, at temperatures ranging from 25 to 180°C. Particularly, the performances of platinum based electro-catalysts with other metals (PtRh, Pt3Ru2 and PtSn) were compared. The temperature dependence of the current for ethanol electro-oxidation from chronoamperometric curves for polycrystalline Pt and catalysts alloys were measured at constant potentials of 500 and 650 mV. The results showed that for the PtSn catalyst at 500 mV and 180°C the current is approximately three hundred times higher than that at 25°C and seven times higher than the other materials investigated at 180°C, for the same oxidation reaction. The apparent activation energies (Ea) values were experimentally determined through the current values from chronoamperometric curves for polycrystalline Pt and PtRh, Pt3Ru2 and PtSn catalysts.

Gasoline spills are sources of groundwater contamination. In the event of a spill, timely remediation efforts can advert most of the potential groundwater contamination due to the immiscibility of gasoline in water. Ethanol functions as a cosolvent that can increase the solubility of gasoline in water. Therefore, the risk of groundwater contamination in the event of a fuel spill increases as the ethanol content in automobile fuels increases. This study examines the effect fuel spill size and ethanol content has on the quantities of toluene, ethylbenzene, m-xylene and o-xylene (TEMO) that dissolve into the aqueous phase at equilibrium. Laboratory experiments were preformed to determine the mass fractions of TEMO in waters that were in contact with various volumes of gasoline and ethanol. UNIFAC is a model capable of predicting the concentrations of TEMO in the aqueous phase of a gasoline-ethanol-water system at equilibrium. In this study, the generalized UNIFAC-LLE method, designed for chemical engineering applications, was used to model the laboratory experiments. New UNIFAC-LLE parameters were developed to improve the model's accuracy in predicting the solubilities of aromatic species in ethanol-water mixtures. The new UNIFAC-LLE parameters were also used to model the laboratory experiments. The modeled results were compared to the analogous laboratory experiments. The UNIFAC-LLE parameters developed in this study improved the model's accuracy in predicting the solubilities of TEMO when the aqueous ethanol mass fraction was between 0.114 and 0.431.

Ethanol (EtOH) is a commonly used drug which exerts many of its effects by altering neurotransmission in the mesolimbic dopamine (DA) system. Although there is little debate that EtOH acts to increase the activity of DA neurons in the ventral tegmental area (VTA), and that this action is necessary for some of the reinforcing effects of EtOH, research in vitro has only been able to demonstrate an excitatory effect on VTA DA neurons in response to very high concentrations of EtOH. These concentrations, typically in the range of 50-100 mM, correspond to sedative or lethal levels for typical humans. Therefore, the significance of findings from in vitro experiments can be difficult to interpret. We sought to determine why high concentrations of EtOH are needed in vitro and whether this could be explained by simple experimental factors, including cytosolic washout from whole cell electrophysiological recordings; heterogeneity among VTA DA neurons, where previous studies may have inadvertently focused on an EtOH-insensitive population; or selection of animal population, where perhaps low EtOH response is characteristic in naïve, rather than EtOH-experienced, animals. To achieve this, we performed cell-attached recordings on a large number of midbrain DA neurons of EtOH-naïve and experienced mice. We report evidence for a highly EtOH-responsive, medially located population of VTA DA neurons. These neurons, found within the rostral linear and interfascicular nuclei and considered “atypical” in terms of physiological criteria ascribed to DA neurons, exhibited a concentration-dependent increase of firing activity in response to EtOH, with some neurons responsive to as little as 20 mM EtOH. In contrast, DA neurons in the lateral VTA and substantia nigra were either unresponsive or responded only to 100 mM EtOH. We then examined neuronal activity following adolescent binge-like alcohol drinking in mice, to determine whether EtOH experience drives increased EtOH sensitivity of DA neurons. We find that in medial VTA DA neurons, drinking experience greatly increased firing activity driven by subsequent exposure to EtOH itself, without altering other measures of intrinsic excitability. This enhanced sensitivity was no longer significant in the presence of glutamate receptor blockade. We attempted to further characterize the EtOH-sensitive, medially located VTA DA neurons by utilizing retrograde tracing to identify a population of nucleus accumbens medial shell-projecting neurons. We find that this population exhibits an increased sensitivity to 50 mM EtOH after adolescent drinking. As a result of these experiments, we have identified a previously uncharacterized, highly EtOH-responsive population of DA neurons in the medial VTA. This population demonstrates an excitatory response to 10 and 20 mM EtOH, concentrations which are more pharmacologically relevant than those typically tested in vitro. We further demonstrate evidence for experience-induced neural adaptations which result in enhanced sensitivity to EtOH in vitro. These adaptations are only apparent in medial VTA DA neurons, and this phenomenon only occurs in response to adolescent drinking. These data provide evidence for a novel form of plasticity in which neurons respond to a primary reinforcer, in this case EtOH, after drinking experience. These findings provide an anatomical and pharmacological distinction between DA neuron subpopulations that will facilitate future mechanistic studies on the actions of EtOH in the VTA.