Une co-exposition au bruit et au toluène a des effets plus néfastes pour l’audition que la somme de ceux induits par chacun des facteurs. L’objectif de cette thèse était d’étudier les mécanismes périphériques et centraux à l’origine de la synergie des effets des solvants aromatiques sur ceux induits par le bruit. Puisque les cellules ciliées externes sont la cible des solvants, le potentiel microphonique cochléaire (PMC) a été utilisé pour suivre l’activité électrique de ces cellules sur des rats exposés à la fois au bruit et au toluène. L’administration intra-carotidienne d’un bolus d’Intralipide contenant du toluène a provoqué une augmentation transitoire de l’amplitude du PMC (~9 dB SPL) déclenchée par un bruit ipsi-latéral de 85 dB SPL. Etant donné que l’augmentation du PMC était dépendante de l’intensité de la stimulation sonore, il était raisonnable de penser que le centre nerveux des réflexes de protection acoustique, le tronc cérébral, pouvait être également une cible du solvant. Cette hypothèse a été confortée par des expériences réalisées sur des rats dont les réflexes de protection avaient été déclenchés par un bruit contra-latéral. Alors que le déclenchement des réflexes s’est traduit par une chute du PMC, le toluène a inhibé les effets des réflexes et plus précisément ceux du réflexe de l’oreille moyenne (ROM). Par ailleurs; des antagonistes des récepteurs cholinergiques ont engendré des augmentations de PMC comparables à celles engendrées par le toluène. Le toluène inhiberait donc les récepteurs cholinergiques des voies efférentes impliquées dans le ROM. L’inhibition du ROM pourrait expliquer la synergie des effets d’une co-exposition au bruit et aux solvants / Combined exposure to noise and toluene has more harmful auditory effects than the sum of those caused by each factor. The goal of this thesis was to study the peripheral and central mechanisms responsible for the synergy between the effects of the solvent and those induced by noise. Since the outer hair cells are the sensitive targets of solvents, the cochlear microphonic potential (CMP) was used to monitor the electrical activity of these cells on rats exposed to both noise and toluene. The intra-carotidial injection of a bolus of intralipid containing toluene provoked a transient increase in CMP magnitude (~9 dB SPL) triggered by a 85-dB SPL ipsi-lateral noise. Given that the CMP increase was dependent on the intensity of the acoustic stimulation, it was reasonable to think that the nervous center of the acoustic reflexes, the brainstem, might have been targeted by the solvent. This assumption was confirmed by investigations performed with rats whose acoustic reflexes had been triggered with a contra-lateral noise. While triggering the reflexes caused a CMP decrease, the toluene injection inhibited the effects of the acoustic reflexes, and more precisely those of the middle ear reflex (MER). In addition, injections of antagonists of cholinergic receptors provoked increases in CMP similar to those generated by toluene. Toluene may therefore inhibit the cholinergic receptors of the efferent pathways involved in the MER. The MER inhibitory could explain the synergy of the effects of combined exposure to noise and solvents

No description available.

Os complexos [RuCl2(PPh3)3], cct-[RuCl2(CO)2(PPh3)2], ttt-[RuCl2(CO)2(PPh3)2], [RuCl2(CO)2(PPh3)(pip)] e [RuCl2(CO)(PPh3)2(DMF)] foram investigados em ROMP de norborneno. O objetivo foi observar a influência eletrônica das moléculas CO, PPh3, piperidina e dimetilformamida como ligantes ancilares na reatividade dos complexos. Experimentos realizados por 1 h à 50°C na razão [NBE]/[Ru] = 5000 mostraram que o complexo [RuCl2(CO)2(PPh3)(pip)] é inerte para ROMP, o complexo cct-[RuCl2(CO)2(PPh3)2] apresentou valores não maiores que 1% e o complexo ttt-[RuCl2(CO)2(PPh3)2] formou 3,75% de poliNBE. Sugere-se que a reação ocorra pela liberação de uma molécula de CO para a formação do complexo carbeno, o que explica a reatividade dos diferentes complexos. O complexo [RuCl2(CO)(PPh3)2(DMF)] foi ativo tanto a 50 como a 25 °C, com 25,0 and 12,2% de rendimento, respectivamente, com a razão [NBE]/[Ru] = 5000 por 1 h. A atividade desse complexo está associada à liberação da molécula DMF, como observado nos espectros de RMN de 31P e UV-visível. Os valores de IPD e Mn foram 1,7-1,8 e na ordem de 104 g/mol, respectivamente. A outra espécie presente em solução foi observada por RMN de 31P na razão de 2/3 o qual foi inerte para ROMP. Assim, considerando apenas 1/3 de espécie ativa, o rendimento de poliNBE pode ser aceito como cerca de 75 e 36% à 50 e 25 °C, respectivamente. O valor à 50 °C é similar àquele obtido com o precursor [RuCl2(PPh3)3] (70% de rendimento em 5 min) e melhor que à 25 °C, no qual o precursor é inerte. Os resultados obtidos mostraram que os complexos contendo CO ácido-π como ligante ancilar podem ser ativos para ROMP de norborneno quando uma posição lábil no complexo ocorra. / The complexes [RuCl2(PPh3)3], cct-[RuCl2(CO)2(PPh3)2], ttt-[RuCl2(CO)2(PPh3)2], [RuCl2(CO)2(PPh3)(pip)] and [RuCl2(CO)(PPh3)2(DMF)] were investigated for ROMP of norbornene. The aim is to observe the electronic influence of the CO, PPh3, piperidine and dimethylformamide molecules as ancillary ligands in the reactivity of the complexes. Experiments performed for 1 h at 50 °C with the ratio [NBE]/[Ru] = 5000 showed that the complex [RuCl2(CO)2(PPh3)(pip)] is inert for ROMP, the complex cct-[RuCl2(CO)2(PPh3)2] yielded values not higher than 1% and the complex ttt-[RuCl2(CO)2(PPh3)2] provided 3.75% of polyNBE. It is suggested that the reactions occur via release of a CO molecule for the formation of the carbene complex, thus explains the reactivity of the different complexes. The complex [RuCl2(CO)(PPh3)2(DMF)] was active either at 50 or 25 °C, with 25.0 and 12.2% yield, respectively, with the ratio [NBE]/[Ru] = 5000 for 1 h. The activity of this complex is associated to the release of the DMF molecule, as observed in the 31P NMR and UV-visible spectra. The IPD and Mn values were 1.7-1.8 and 104 g/mol in magnitude. Other specie present in solution was observed in the 31P NMR spectra in a ratio of 2/3 which is inert for ROMP. Thus, considering just 1/3 of active specie, the yield of polyNBE can be acceptable as c.a. 75 and 36% at 50 or 25 °C, respectively. The value at 50 °C is similar to that obtained with the precursor [RuCl2(PPh3)3] (70% yield for 5 min) and better at 25 °C, where the precursor is inert. The obtained results showed that the complexes containing π-acid CO as ancillary ligand can be active for ROMP of norbornene when a labile position in the complex occurs.

Seja C uma co-álgebra. Consideremos o anel de convolução C*, que é a álgebra dual de C. Dado um co-módulo à direita (resp. à esquerda) sobre C é possível definir um C*-módulo à esquerda (resp. à direita) racional. Nesta tese, estudamos as noções correspondentes dos conceitos de primos, fortemente primos, semiprimos e fortemente semiprimos, que são encontrados na literatura em [2], [3], [4], [13] e [17], para co-módulos. A noção do conceito de primo é obtida também para co-álgebras. Mostramos que uma co-álgebra C é prima se, e somente se, C é uma co-álgebra simples.

Seja C uma co-álgebra. Consideremos o anel de convolução C*, que é a álgebra dual de C. Dado um co-módulo à direita (resp. à esquerda) sobre C é possível definir um C*-módulo à esquerda (resp. à direita) racional. Nesta tese, estudamos as noções correspondentes dos conceitos de primos, fortemente primos, semiprimos e fortemente semiprimos, que são encontrados na literatura em [2], [3], [4], [13] e [17], para co-módulos. A noção do conceito de primo é obtida também para co-álgebras. Mostramos que uma co-álgebra C é prima se, e somente se, C é uma co-álgebra simples.

Seja C uma co-álgebra. Consideremos o anel de convolução C*, que é a álgebra dual de C. Dado um co-módulo à direita (resp. à esquerda) sobre C é possível definir um C*-módulo à esquerda (resp. à direita) racional. Nesta tese, estudamos as noções correspondentes dos conceitos de primos, fortemente primos, semiprimos e fortemente semiprimos, que são encontrados na literatura em [2], [3], [4], [13] e [17], para co-módulos. A noção do conceito de primo é obtida também para co-álgebras. Mostramos que uma co-álgebra C é prima se, e somente se, C é uma co-álgebra simples.

Os complexos [RuCl2(PPh3)3], cct-[RuCl2(CO)2(PPh3)2], ttt-[RuCl2(CO)2(PPh3)2], [RuCl2(CO)2(PPh3)(pip)] e [RuCl2(CO)(PPh3)2(DMF)] foram investigados em ROMP de norborneno. O objetivo foi observar a influência eletrônica das moléculas CO, PPh3, piperidina e dimetilformamida como ligantes ancilares na reatividade dos complexos. Experimentos realizados por 1 h à 50°C na razão [NBE]/[Ru] = 5000 mostraram que o complexo [RuCl2(CO)2(PPh3)(pip)] é inerte para ROMP, o complexo cct-[RuCl2(CO)2(PPh3)2] apresentou valores não maiores que 1% e o complexo ttt-[RuCl2(CO)2(PPh3)2] formou 3,75% de poliNBE. Sugere-se que a reação ocorra pela liberação de uma molécula de CO para a formação do complexo carbeno, o que explica a reatividade dos diferentes complexos. O complexo [RuCl2(CO)(PPh3)2(DMF)] foi ativo tanto a 50 como a 25 °C, com 25,0 and 12,2% de rendimento, respectivamente, com a razão [NBE]/[Ru] = 5000 por 1 h. A atividade desse complexo está associada à liberação da molécula DMF, como observado nos espectros de RMN de 31P e UV-visível. Os valores de IPD e Mn foram 1,7-1,8 e na ordem de 104 g/mol, respectivamente. A outra espécie presente em solução foi observada por RMN de 31P na razão de 2/3 o qual foi inerte para ROMP. Assim, considerando apenas 1/3 de espécie ativa, o rendimento de poliNBE pode ser aceito como cerca de 75 e 36% à 50 e 25 °C, respectivamente. O valor à 50 °C é similar àquele obtido com o precursor [RuCl2(PPh3)3] (70% de rendimento em 5 min) e melhor que à 25 °C, no qual o precursor é inerte. Os resultados obtidos mostraram que os complexos contendo CO ácido-π como ligante ancilar podem ser ativos para ROMP de norborneno quando uma posição lábil no complexo ocorra. / The complexes [RuCl2(PPh3)3], cct-[RuCl2(CO)2(PPh3)2], ttt-[RuCl2(CO)2(PPh3)2], [RuCl2(CO)2(PPh3)(pip)] and [RuCl2(CO)(PPh3)2(DMF)] were investigated for ROMP of norbornene. The aim is to observe the electronic influence of the CO, PPh3, piperidine and dimethylformamide molecules as ancillary ligands in the reactivity of the complexes. Experiments performed for 1 h at 50 °C with the ratio [NBE]/[Ru] = 5000 showed that the complex [RuCl2(CO)2(PPh3)(pip)] is inert for ROMP, the complex cct-[RuCl2(CO)2(PPh3)2] yielded values not higher than 1% and the complex ttt-[RuCl2(CO)2(PPh3)2] provided 3.75% of polyNBE. It is suggested that the reactions occur via release of a CO molecule for the formation of the carbene complex, thus explains the reactivity of the different complexes. The complex [RuCl2(CO)(PPh3)2(DMF)] was active either at 50 or 25 °C, with 25.0 and 12.2% yield, respectively, with the ratio [NBE]/[Ru] = 5000 for 1 h. The activity of this complex is associated to the release of the DMF molecule, as observed in the 31P NMR and UV-visible spectra. The IPD and Mn values were 1.7-1.8 and 104 g/mol in magnitude. Other specie present in solution was observed in the 31P NMR spectra in a ratio of 2/3 which is inert for ROMP. Thus, considering just 1/3 of active specie, the yield of polyNBE can be acceptable as c.a. 75 and 36% at 50 or 25 °C, respectively. The value at 50 °C is similar to that obtained with the precursor [RuCl2(PPh3)3] (70% yield for 5 min) and better at 25 °C, where the precursor is inert. The obtained results showed that the complexes containing π-acid CO as ancillary ligand can be active for ROMP of norbornene when a labile position in the complex occurs.

This research examines the physical and economic feasibility of 5% biomass co-firing in the coal-fired power plants of Utah. Transportation models is used to find out the physical feasibility of 5% biomass co-firing, as well as locate the supply zone for each power plant that would minimize the transportation cost. Additional cost required for 5% biomass co-firing and the economic benefits associated with biomass co-firing are calculated. The additional cost required for 5% biomass co-firing is estimated to be $34.84 million. Previous studies on CO2 emission reduction are used to compute the economic benefit attain from CO2 reduction by selling carbon credits in the carbon trading market. Based on 2010 emission record in Utah, 5% biomass co-firing might reduce 0.71~2.13 million metric tons of CO2 and, in turn, bring the annual economic benefit of $11.37~$34.10 million assuming $16/ton of CO2 in the emission trading market. The regression model is used to find the relationship between PM emission and the human health damage. The regression results show that decreases in 1% of PM25 emission improves the human health in U.S. by 0.65%~0.67% in value. Five percent biomass co-firing generates annual economic benefits of $6.72~$9.93 million in Utah depending on the emission reduction scenarios. Note that these might not be the precise economic benefit from the biomass co-firing in Utah because elasticities estimated in the regression are expected to be lower in Utah. This is because most of power plants in Utah are located in open areas. Altogether, the economic benefit from 5% biomass co-firing is estimated to be $38.55 million assuming the medium emission reduction scenario, moderate carbon price ($16/ton of CO2) which is higher than the additional cost of biomass co-firing to generate electricity ($34.84 million). The benefit cost ratio is calculated as 1.107. Five percent biomass co-firing is economically feasible when benefits from all the positive externalities are included. The findings of the research suggest that in order to make 5% biomass co-firing physically and economically feasible, Utah needs cooperation from Idaho and the price of carbon and biomass would have to be $16 and $20, respectively.

No description available.

No description available.