Philosophiae Doctor - PhD / The production of biodiesel (methyl esters) from vegetable oils represents analternative means of producing liquid fuels from biomass, and one which is growing rapidly in commercial importance and relevance due to increase in petroleum prices and the environmental advantages the process offers. Commercially, biodiesel is produced from vegetable oils, as well as from waste cooking oils and animal fats. These oils are typically composed of C14-C20 fatty acid triglycerides. In order to produce a fuel that is suitable for use in diesel engines, these triglycerides are usually converted into the respective mono alkyl esters by base-catalyzed transesterification with short chain alcohol, usually methanol. In the first part of this study, the transesterification reactions of three different vegetable oils; sunflower (SFO), soybean (SBO) and waste cooking oil (WCO) with methanol was studied using potassium hydroxide as catalyst in a conventional batch process. The production of biodiesel from waste cooking oil was also studied via continuous operation systems (employing the use of low frequency ultrasonic technology and the jet loop reactor). The characterisation of the feedstock used and the methyl ester products were determined by different analytical techniques such as gas chromatography (GC), high performance liquid chromatography (HPLC) and thin layer chromatography (TLC). The effects of different reaction parameters (catalyst amount, methanol to oil ratio, reaction temperature, reaction time) on methyl ester/FAME yield were studied and the optimum reaction conditions of the different process systems were determined. The optimum reaction conditions for production of methyl esters via the batch process with the fresh oil samples (SFO and SBO) were established as follows: a reaction time of 60 min at 60 ºC with a methanol: oil ratio of 6:1 and 1.0 KOH % wt/wt of oil; while the optimum reaction conditions for the used oil (WCO) was observed at a reaction time of 90 min at 60 ºC, methanol: oil ratio of 6:1 and 1.5% KOH wt/wt of oil. The optimum reaction conditions for the transesterification of the WCO via ultrasound technology applied in a continuous system in this study were: a reaction time of 30 min, 30 ºC, 6:1 methanol/oil ratio and a 0.75 wt% (KOH) catalyst concentration. The ultrasound assisted transesterification reactions performed at optimum conditions on the different oil samples led to higher yields of methyl esters (96.8, 98.32 and 97.65 % for WCO, SFO and SBO respectively) compared to methyl esters yields (90, 95 and 96 % for WCO, SFO and SBO respectively) obtained when using conventional batch procedures. A considerable increase in yields of the methyl esters in the ultrasound assisted reaction process were obtained at room temperature, in a remarkably short time span (completed in 30 min) and with a lower amount of catalyst (0.75 wt % KOH) while the results from the continuous jet loop process system showed even better results, at an optimum reaction condition of 25 min of reaction, a methanol: oil ratio of 4:1 and a catalyst amount of 0.5 wt%. This new jet loop process allowed an added advantage of intense agitation for an efficient separation and adequate purification of the methyl esters phase at a reduced time of 30 min. The use of homogeneous catalysts in conventional processes poses many disadvantages; heterogeneous catalysts on the other hand are attractive on the basis that their use could enable the biodiesel production to be more readily performed as a continuous process resulting in low production costs. Consequently, a solid base catalyst (KNO3/FA) prepared from fly ash (obtained from Arnot coal power station, South Africa) and a new zeolite, FA/Na-X synthesized from the same fly ash were used as solid base catalysts in the transesterification reactions in the conversion of a variety of oil feedstock with methanol to methyl esters. Since fly ash is a waste product generated from the combustion of coal for power generation, its utilization in this manner would allow for its beneficiation (as a catalytic support material and raw material for zeolite synthesis) in an environmentally friendly way aimed at making the transesterification process reasonably viable. Arnot fly ash (AFA) was loaded with potassium (using potassium nitrate as precursor) via a wet impregnation method while the synthesized zeolite FA/Na-X was ion exchanged with potassium (using potassium acetate as precursor) to obtain the KNO3/FA and FA/K-X catalysts respectively. Several analytical techniques were applied for characterization purposes. The results of the XRD and XRF showed that the AFA predominantly contained some mineral phases such as quartz, mullite, calcite and lime. The high concentration of CaO in AFA was apparent to be beneficial for the use of fresh fly ash as a support material in the heterogeneous catalysed transesterification reactions. XRD characterisation of KNO3/FA results indicated that the structure of KNO3/FA gradually changed with the increase in KNO3 loading. The catalyst function was retained until the loading of KNO3 was over 10 %. IR spectra showed that the KNO3 was decomposed to K2O on the fly ash support during preparation at a calcination temperature of 500 ºC. The CO2-TPD of the KNO3/FA catalysts showed that two basic catalytic sites were generated which were responsible for high catalytic abilities observed in the transesterification reactions of sunflower oil to methyl esters. On the other hand, XRD results for the as- received zeolite synthesized from AFA showed typical diffraction peaks of zeolite NaX. SEM images of the FA /NaX showed nano platelets unique morphology different from well known pyramidal octahedral shaped crystal formation of faujasite zeolites and the morphology of the FA /KX zeolite did not show any significant difference after ion exchange. The fly ash derived zeolite NaX (FA /NaX) exhibited a high surface area of 320 m2/g. The application of the KNO3/FA catalysts in the conversion reactions to produce methyl esters (biodiesel) via transesterification reactions revealed methyl ester yield of 87.5 % with 10 wt% KNO3 at optimum reaction conditions of methanol: oil ratio of 15:1, 5 h reaction time, catalyst amount of 15 g and reaction temperature 160 °C, while with the use of the zeolite FA/K-X catalyst, a FAME yield of 83.53 % was obtained for 8 h using the ion exchanged Arnot fly ash zeolite NaX catalyst (FA/KX) at reaction conditions of methanol: oil ratio of 6:1, catalyst amount of 3 % wt/wt of oil and reaction temperature of 65 ºC. Several studies have been carried out on the production of biodiesel using different heterogeneous catalysts but this study has been able to uniquely demonstrate the utilization of South African Class F AFA both as a catalyst support and as a raw material for zeolite synthesis; these catalyst materials subsequently applied sucessfully as solid base catalysts in the production of biodiesel. / South Africa

Bisphenols are used in the process of polymerization of polycarbonate plastics and epoxy resins. Bisphenols can easily migrate out of plastic products and enter the gastrointestinal system. By increasing colonic inflammation in mice, disrupting the intestinal bacterial community structure and altering the microbial membrane transport system in zebrafish, bisphenols seem to interfere with the gut microbiome. The highly abundant human commensal bacterium Bacteroides thetaiotaomicron was exposed to bisphenols (Bisphenol A (BPA), Bisphenol F (BPF), Bisphenol S (BPS)), to examine the mode of action, in particular of BPF. All chemicals caused a concentration-dependent growth inhibition and the half-maximal effective concentration (EC50) corresponded to their individual logP values, a measure of their hydrophobicity. B. thetaiotaomicron exposed to BPF decreased membrane fluidity with increasing BPF concentrations. Physiological changes including an increase of acetate concentrations were observed. On the proteome level, a higher abundance of several ATP synthase subunits and multidrug efflux pumps suggested an increased energy demand for adaptive mechanisms after BPF exposure. Defense mechanisms were also implicated by a pathway analysis that identified a higher abundance of members of resistance pathways/strategies to cope with xenobiotics (i.e., antibiotics). Here, we present further insights into the mode of action of bisphenols in a human commensal gut bacterium regarding growth inhibition, and the physiological and functional state of the cell. These results, combined with microbiota-directed effects, could lead to a better understanding of host health disturbances and disease development based on xenobiotic uptake.

No description available.

Ce travail porte sur la caractérisation physico-chimique de l'huile de Jatropha Curcas et sa capacité à remplacer l'huile minérale dans les transformateurs de puissance. Ce produit présente plusieurs avantages sur les autres huiles végétales comme l'huile de palme ou l'huile de colza, qui recommandent sa production et son utilisation. En effet, la plante de Jatropha Curcas peut être cultivée sur des sols pauvres à faibles précipitations, évitant ainsi d'utiliser des sols plus fertiles pour sa culture permettant ainsi aux petits exploitants de réserver leurs terres aux cultures de base. Cette plante peut pousser facilement dans des zones où les niveaux de précipitations annuelles sont nettement inférieures à celles requises par d'autres espèces telles que le colza, le tournesol, le soja, le maïs, le palmier à huile et d'autres. Elle peut être cultivée sur tous les types de sol en Indonésie, même sur des terres arides, dans de nombreuses régions de l'Indonésie orientale, inexploitées en raison des difficultés à planter d'autres cultures. En outre, l'huile de Jatropha Curcas est un produit non alimentaire. En faisant subir à l’huile de Jatropha Curcas brute une estérification à base alcaline avec de l'hydroxyde de potassium (KOH), on obtient de l’huile de méthylester de Jatropha Curcas (JMEO) dont la viscosité et l’acidité sont acceptables pour les équipements à haute tension en particulier pour les transformateurs de puissance. Les propriétés physico-chimiques et électriques de JMEO ont été mesurées ainsi que celles de l'huile minérale (MO) pour la comparaison. Pour les propriétés physico-chimiques, il s’agit de la densité relative, la teneur en eau, la viscosité, l'acidité, l'indice d'iode, la corrosivité, le point d'éclair, le point d'écoulement, la couleur, l'examen visuel, et la teneur en ester méthylique. Quant aux propriétés électriques, elles concernent la rigidité diélectrique sous différentes formes de tension (alternative, continu et choc de foudre), les phénomènes de pré-claquage et de claquage sous choc de foudre, les décharges glissantes sur les surfaces de carton comprimé, immergé dans JMEO et MO. Les résultats obtenus montrent que les tensions de claquage moyennes en continu et en choc de foudre des huiles JMEO et MO sont très proches ; la tension de claquage moyenne de JMEO est même plus élevée que celle de l'huile minérale (de type naphténique). La mesure des tensions de claquage des mélanges d'huiles «80% JMEO + 20% MO» et «50% JMEO et 50% MO» montrent que la tension de claquage du mélange «80% JMEO + 20% MO» est toujours supérieure à celle de l'huile minérale sous tensions alternative et continue. Cela indique que le mélange d'huile minérale et de JMEO avec un rapport de 20:80 ne dégrade pas ses performances. Le mélange d'huiles peut se produire lors du remplacement de l'huile minérale par JMEO dans les transformateurs installés et en exploitation. L'analyse des caractéristiques des streamers (la forme, le temps d'arrêt, le courant associé et la charge électrique) se développant dans les huiles JMEO et MO sous tension impulsionnelle de foudre, montre une grande similitude. Aussi, la longueur finale (Lf) et la densité des branches des décharges surfaciques se propageant sur le carton comprimé immergé dans l'huile de Jatropha Curcas de méthylester (JMEO) et de l'huile minérale (MO), sous tensions de choc de foudre positif et négatif (1,2/50 μs), pour deux configurations d'électrodes divergentes (électrode pointe haute tension perpendiculaire et tangente au carton, respectivement), sont fortement influencées par l'épaisseur du carton comprimé. Pour une épaisseur donnée, Lf augmente avec la tension et décroît lorsque l'épaisseur augmente. Lf est plus long lorsque la pointe est positive que lorsque la pointe est négative. Pour une tension et une épaisseur du carton comprimé donnée, les valeurs de Lf dans l’huile minérale et l’huile JMEO sont très proches. [...] / This work is aimed at the investigation of the physicochemical characterization of Jatropha Curcas seeds oil and its capacity to be an alternative option to replace mineral oil in power transformers. This product presents several advantages that recommend both its production and usage over those of other vegetable oils as crude palm oil and rapeseeds oil. Indeed, it may be grown on marginal or degraded soils avoiding thus the need to utilize those more fertile soils currently being used by smallholders to grow their staple crops; and it will readily grow in areas where annual rainfall levels are significantly lower than those required by other species such as palm oil, rape-seeds oil, sunflower oil, soybeans oil, corn oil and others. For instance, these plants can grow on all soil types in Indonesia, even on barren soil. The barren soil types can be found in many parts of eastern Indonesia that remain untapped because of the difficulty planted with other crops. Moreover, jatropha curcas oil is nonfood crops. Jatropha Curcas oil was processed by alkali base catalyzed esterification process using potassium hydroxide (KOH) to produce Jatropha Curcas methyl ester oil (JMEO) has a viscosity and a acidity that are acceptable for high voltage equipment especially in power transformer. The physicochemical and electrical properties of JMEO were measured as well as those of mineral oil (MO) for comparison. The physicochemical properties cover relative density, water content, viscosity, acidity, iodine number, corrosivity, flash point, pour point, color, visual examination, and methyl ester content. Meanwhile the electrical properties cover dielectric strength under AC, DC and lightning impulse voltages, pre-breakdown / streamers under lightning impulse voltage, creeping discharge over pressboard immersed in JMEO and MO. The obtained results show that the average DC and lightning impulse breakdown voltages of JMEO and MO are too close, even the average AC breakdown voltage of JMEO are higher than that of mineral oil (napthenic type). The measurement of breakdown voltages of two oil mixtures namely “80% JMEO + 20% MO” and “50% JMEO and 50% MO” shows that the breakdown voltage of the first mixture (i.e., “80%JMEO+20%MO”) is always higher than that of mineral oil under both AC and DC voltages. This indicates that mixing 20:80 mineral oil to JMEO ratio does not degrade its performance. The mixing of oils can occur when replacing mineral oil by JMEO in installed transformers. The analysis of the streamers characteristics (namely; shape, stopping length, associated current and electrical charge) developing in JMEO and MO under lightning impulse voltages, shows that these are too close (similar). It is also shown that the stopping (final) length Lf and the density of branches of creeping discharges propagating over pressboard immersed in Jatropha Curcas methyl ester oil (JMEO) and mineral oil (MO), under positive and negative lightning impulse voltages (1.2/50 μs), using two divergent electrode configurations (electrode point perpendicular and tangential to pressboard), are significantly influenced by the thickness of pressboard. For a given thickness, Lf increases with the voltage and decreases when the thickness increases. Lf is longer when the point is positive than with a negative point. For a given voltage and thickness of pressboard, the values of Lf in mineral oil and JMEO are very close. It appears from this work that JMEO could constitute a potential substitute for mineral oil for electrical insulation and especially in high voltage power transformers.

O uso de drogas por mulheres em idade reprodutiva é considerado um grave problema de saúde pública mundial. O mecônio é a primeira excreção do recém-nascido e tem sido utilizado como uma matriz alternativa em análises toxicológicas. A extração em fase sólida (SPE) é um método amplamente utilizado para a purificação e concentração dos analitos em amostras biológicas no campo da análise forense. A maioria dos produtos de SPE convencionais requerem volumes relativamente grandes de solventes levando a um custo acrescido por amostra e um aumento no tempo de processamento da amostra. As ponteiras de extração com fase sólida modificada (DPX) foram utilizadas como uma alternativa aos cartuchos SPE tradicionais. A técnica combina eficiência e rapidez no procedimento de extração, com redução significativa no consumo de solvente e na quantidade de amostra. O objetivo desse estudo foi desenvolver e validar um método para a determinação de nicotina, cotinina, cocaína, benzoilecgonina, cocaetileno e éster metil anidroecgonina em amostras de mecônio usando DPX e cromatografia em fase gasosa acoplada à espectrometria de massa (GC/MS). Os resultados da validação indicaram uma extração eficiente, exata e precisa, com recuperação entre 50-98%, exatidão entre 92-106%, precisão intra-ensaio 4-12% e precisão inter-ensaio 6 a 12%. As curvas de calibração foram lineares com valores de R2 superiores a 0,99; os limites de detecção (LOD) variaram entre 2,5-15 ng/g e os limites de quantificação (LOQ) entre 10-20 ng/g. O método DPX-GC/MS mostrou ser eficaz para análise traços de drogas presentes em amostras de mecônio. Após desenvolvimento e validação, o método foi aplicado em 50 amostras de mecônio coletadas no berçário da Maternidade do Complexo Aeroporto (MATER) na cidade de Ribeirão Preto - São Paulo, Brasil. / Drug abuse by pregnant women is considered a serious public health problem worldwide. Meconium is the first excretion in newborns and has been used as an alternative matrix to evaluate in utero drug exposure. Solid phase extraction (SPE) is widely employed to prepare and cleanup samples in the field of forensic analysis. Most SPE products require large volumes of solvent, which culminates in longer sample processing times; increased cost per sample and higher limits of detection. Disposable Pipette Extraction tips (DPX) have been used as an alternative to traditional SPE cartridges. They combine efficient and rapid extraction with reduced solvent consumption. The purpose of this study was to develop and validate a method to determine nicotine, cotinine, cocaine, benzoylecgonine, cocaethylene and methyl ester anhydroecgonine in meconium using DPX and GC/MS. Validation results indicated extraction efficiency, ranged between 50-98%, accuracy 92-106%, intra-assay precision 4-12% and inter-assay precision 6 to 12%. Linear calibration curves resulted in R2 values greater than 0.99; limits of detection ranged from 2.5 - 15 ng/g and the limit of quantitation from 10 - 20 ng/g. The DPX-GC/MS method provided to selectively analyze trace concentrations of drugs in meconium samples. Finally, the developed and validated method was applied to 50 meconium samples collected at the nursery of Maternidade do Complexo Aeroporto (MATER) in the city of Ribeirão Preto - São Paulo, Brazil.

O crack é a forma fumada de administração da cocaína com o maior potencial para causar dependência. Até 80% da sua fumaça consiste no produto de pirólise da cocaína, a metilecgonidina (AEME). Apesar do vasto conhecimento acerca dos efeitos e prejuízos causados pela cocaína, nenhum trabalho avaliou os efeitos da AEME na farmacodependência, objetivo deste trabalho. Ratos adultos machos Wistar foram expostos à salina, à AEME 3 mg/kg, à cocaína 15 mg/kg e a associação entre cocaína e AEME, intraperitonealmente, em duas situações: 1) exposição prolongada (administração todos os dias, por 9 dias); 2) sensibilização comportamental dependente de contexto (administração em dias alternados, por 5 dias e 7 dias de abstinência, seguido do desafio). A dose de AEME foi definida pela avaliação da atividade locomotora em teste agudo. A AEME foi capaz de aumentar a atividade locomotora após exposição prolongada e potencializar a expressão da sensibilização comportamental dependente de contexto induzida pela cocaína. A concentração de dopamina e seus metabólitos aumentaram no caudado-putâmen em todos os grupos, sendo observado um sinergismo entre cocaína e AEME no grupo da associação. No núcleo accumbens, foi observado aumento de dopamina apenas nos grupos cocaína e associação. Paralelamente, houve aumento da relação p-CREB/CREB 60 minutos após a administração aguda de AEME 3 mg/kg e cocaína 15 mg/kg, tanto no caudado-putâmen quanto no núcleo accumbens, assim como nos grupos cocaína e associação após a sensibilização comportamental dependente de contexto. Com a finalidade de determinar o mecanismo de ação da AEME, foi realizado um estudo farmacológico detalhado dessa substância em células CHO-K1 de rato expressando heterologamente os receptores colinérgicos muscarínicos subtipos 1 a 5, uma vez que estudos anteriores sugeriram uma interação entre a AEME e os receptores colinérgicos muscarínicos. O ensaio de competição com [3H]NMS mostrou uma pequena preferência da AEME para o subtipo M2. Estudos funcionais (mobilização de cálcio) revelaram um efeito agonista parcial da AEME para os subtipos M1 e M3 e antagonista para os demais subtipos, dando suporte à hipótese colinérgica de ação da AEME. Nossos resultados indicam que a AEME isoladamente não foi capaz de causar sensibilização, mas potencializou a ação da cocaína quando coadministrada. O efeito antagonista da AEME em receptores subtipo M2 e M4 no caudado-putâmen, e M4 e M5 no núcleo accumbens causaram aumento de dopamina nessas regiões encefálicas, onde a atividade colinérgica medeia sua liberação. / Crack cocaine is the smoked form of cocaine with the highest potential for addiction. Up to 80% of crack smoke consists of cocaines pyrolysis product anhydroecgonine methyl ester (AEME). Despite of many studies regarding cocaine effects and its hazardousness, few reports have assessed AEME\'s role in addiction, the aim of this study. Adult male Wistar rats were i.p. dosed with either saline, 3 mg/kg AEME, cocaine 15 mg/kg, or cocaine-AEME combination in two situations: 1) prolonged exposure (drugs administered every day for 9 days); 2) behavioral sensitization context specific (drugs administered in alternating days for 5 days, followed by 7-days abstinence period and a challenge injection). AEME dose was chosen based on locomotor activity after an acute test. AEME increased locomotor activity in the prolonged exposure and it potentiated cocaine-induced behavioral sensitization. Dopamine level and its metabolites were elevated in the caudate-putamen in all non-saline groups with a synergic effect between cocaine and AEME in the cocaine-AEME group. In the nucleus accumbens, dopamine was elevated only in cocaine and cocaine-AEME groups. At the same time, p-CREB/CREB ratio, increased 60 minutes after an acute administration of 3 mg/kg AEME and 15 mg/kg cocaine in both caudate-putamen and nucleus accumbens, the same result observed in both cocaine and cocaine-AEME groups after behavioral sensitization. Once previous studies suggested AEME interacts with muscarinic acetylcholine receptors, a detailed pharmacological analysis of AEME at rat muscarinic acetylcholine receptors subtypes 1-5 heterologously expressed in CHO-K1 cells was performed to determine a mechanism for the novel effects of AEME. [3H]NMS competition binding showed a slight preference for M2 subtype; functional studies (Ca2+ mobilization) revealed partial agonist effects at M1 and M3 and antagonist effects at the remaining subtypes, supporting the cholinergic hypothesis of AEME\'s effects. Our results indicate AEME alone does not elicit behavior sensitization but significantly potentiates cocaine sensitization when co-administered. AEME antagonism effects at M2 and M4 muscarinic acetylcholine receptors subtypes in the caudate-putamen, and M4 and M5 muscarinic acetylcholine receptors subtypes in the nucleus accumbens resulted in dopamine increase in these brain regions, where its release is mediated by cholinergic activity.

O crack é a forma fumada de administração da cocaína com o maior potencial para causar dependência. Até 80% da sua fumaça consiste no produto de pirólise da cocaína, a metilecgonidina (AEME). Apesar do vasto conhecimento acerca dos efeitos e prejuízos causados pela cocaína, nenhum trabalho avaliou os efeitos da AEME na farmacodependência, objetivo deste trabalho. Ratos adultos machos Wistar foram expostos à salina, à AEME 3 mg/kg, à cocaína 15 mg/kg e a associação entre cocaína e AEME, intraperitonealmente, em duas situações: 1) exposição prolongada (administração todos os dias, por 9 dias); 2) sensibilização comportamental dependente de contexto (administração em dias alternados, por 5 dias e 7 dias de abstinência, seguido do desafio). A dose de AEME foi definida pela avaliação da atividade locomotora em teste agudo. A AEME foi capaz de aumentar a atividade locomotora após exposição prolongada e potencializar a expressão da sensibilização comportamental dependente de contexto induzida pela cocaína. A concentração de dopamina e seus metabólitos aumentaram no caudado-putâmen em todos os grupos, sendo observado um sinergismo entre cocaína e AEME no grupo da associação. No núcleo accumbens, foi observado aumento de dopamina apenas nos grupos cocaína e associação. Paralelamente, houve aumento da relação p-CREB/CREB 60 minutos após a administração aguda de AEME 3 mg/kg e cocaína 15 mg/kg, tanto no caudado-putâmen quanto no núcleo accumbens, assim como nos grupos cocaína e associação após a sensibilização comportamental dependente de contexto. Com a finalidade de determinar o mecanismo de ação da AEME, foi realizado um estudo farmacológico detalhado dessa substância em células CHO-K1 de rato expressando heterologamente os receptores colinérgicos muscarínicos subtipos 1 a 5, uma vez que estudos anteriores sugeriram uma interação entre a AEME e os receptores colinérgicos muscarínicos. O ensaio de competição com [3H]NMS mostrou uma pequena preferência da AEME para o subtipo M2. Estudos funcionais (mobilização de cálcio) revelaram um efeito agonista parcial da AEME para os subtipos M1 e M3 e antagonista para os demais subtipos, dando suporte à hipótese colinérgica de ação da AEME. Nossos resultados indicam que a AEME isoladamente não foi capaz de causar sensibilização, mas potencializou a ação da cocaína quando coadministrada. O efeito antagonista da AEME em receptores subtipo M2 e M4 no caudado-putâmen, e M4 e M5 no núcleo accumbens causaram aumento de dopamina nessas regiões encefálicas, onde a atividade colinérgica medeia sua liberação. / Crack cocaine is the smoked form of cocaine with the highest potential for addiction. Up to 80% of crack smoke consists of cocaines pyrolysis product anhydroecgonine methyl ester (AEME). Despite of many studies regarding cocaine effects and its hazardousness, few reports have assessed AEME\'s role in addiction, the aim of this study. Adult male Wistar rats were i.p. dosed with either saline, 3 mg/kg AEME, cocaine 15 mg/kg, or cocaine-AEME combination in two situations: 1) prolonged exposure (drugs administered every day for 9 days); 2) behavioral sensitization context specific (drugs administered in alternating days for 5 days, followed by 7-days abstinence period and a challenge injection). AEME dose was chosen based on locomotor activity after an acute test. AEME increased locomotor activity in the prolonged exposure and it potentiated cocaine-induced behavioral sensitization. Dopamine level and its metabolites were elevated in the caudate-putamen in all non-saline groups with a synergic effect between cocaine and AEME in the cocaine-AEME group. In the nucleus accumbens, dopamine was elevated only in cocaine and cocaine-AEME groups. At the same time, p-CREB/CREB ratio, increased 60 minutes after an acute administration of 3 mg/kg AEME and 15 mg/kg cocaine in both caudate-putamen and nucleus accumbens, the same result observed in both cocaine and cocaine-AEME groups after behavioral sensitization. Once previous studies suggested AEME interacts with muscarinic acetylcholine receptors, a detailed pharmacological analysis of AEME at rat muscarinic acetylcholine receptors subtypes 1-5 heterologously expressed in CHO-K1 cells was performed to determine a mechanism for the novel effects of AEME. [3H]NMS competition binding showed a slight preference for M2 subtype; functional studies (Ca2+ mobilization) revealed partial agonist effects at M1 and M3 and antagonist effects at the remaining subtypes, supporting the cholinergic hypothesis of AEME\'s effects. Our results indicate AEME alone does not elicit behavior sensitization but significantly potentiates cocaine sensitization when co-administered. AEME antagonism effects at M2 and M4 muscarinic acetylcholine receptors subtypes in the caudate-putamen, and M4 and M5 muscarinic acetylcholine receptors subtypes in the nucleus accumbens resulted in dopamine increase in these brain regions, where its release is mediated by cholinergic activity.

In the production of biodiesel via the transesterification of vegetable oils, purification to international standards is challenging. A key measure of biodiesel quality is the level of free glycerol in the biodiesel. In order to remove glycerol from fatty acid methyl ester (FAME or biodiesel), a membrane separation setup was tested. The main objective of this thesis was to develop a membrane process for the separation of free glycerol dispersed in FAME after completion of the transesterification reaction and to investigate the effect of different factors on glycerol removal. These factors included membrane pore size, pressure, temperature, and methanol, soap and water content. First, a study of the effect of different materials present in the transesterification reaction, such as water, soap, and methanol, on the final free glycerol separation was performed using a modified polyacrylonitrile (PAN) membrane, with 100 kD (ultrafiltration) molecular weight cut off for all runs at 25°C. Results showed low concentrations of water had a considerable effect in removing glycerol from the FAME. The mechanism of separation of free glycerol from FAME was due to the removal of an ultrafine dispersed glycerol-rich phase present in the untreated (or raw) FAME. The size of the droplets and the free glycerol separation both increased with increasing water content of the FAME. Next, three types of polymeric membranes in the ultrafiltration range with different molecular weight cut off, were tested at three fixed operating pressures and three operating temperatures (0, 5 and 25oC) to remove the free glycerol from a biodiesel reactor effluent. The ASTM standard for free glycerol concentration was met for the experiments performed at 25°C. The results of this study indicate that glycerol could be separated from raw FAME to meet ASTM and EN standards at methanol feed concentrations of up to 3 mass%. The process was demonstrated to rely on the formation of a dynamic polar layer on the membrane surface. Ceramic membranes of different pore sizes (0.05 µm (ultrafiltration (UF) range) and 0.2 µm (microfiltration (MF) range)) were used to treat raw FAME directly using the membrane separation set up at temperatures of 0, 5 and 25°C. The results were encouraging for the 0.05 µm pore size membrane at the highest temperature (25°C). The effect of temperature on glycerol removal was evident from its relation with the concentration factor (CF). Higher temperatures promoted the achievement of the appropriate CF value sooner for faster separation. Membrane pore size was also found to affect separation performance. A subsequent study revealed the effect of different variables on the size of the glycerol droplets using dynamic light scattering (DLS). A key parameter in the use of membrane separation technology is the size of the glycerol droplets and the influence of other components such as water, methanol and soaps on that droplet size. The effect of water, methanol, soap and glycerol on the size of suspended glycerol droplets in FAME was studied using a 3-level Box-Behnken experimental design technique. Standard statistical analysis techniques revealed the significant effect of water and glycerol on increasing droplet size while methanol and soap served to reduce the droplet size. Finally, a study on the effect of trans-membrane pressure (TMP) at different water concentrations in the FAME phase on glycerol removal using UF (0.03 µm pore size, polyethersulfone (PES)) and MF (0.1 and 0.22 µm pore sizes, PES) membranes at 25, 40 and 60°C was performed. Results showed that running at 25°C for the two membrane types produced the best results for glycerol removal and exceeded the ASTM and EN standards. An enhancement of glycerol removal was found by adding small amounts of water up to the maximum solubility limit in biodiesel. An increase in temperature resulted in an increase in the solubility of water in the FAME and less effective glycerol removal. Application of cake filtration theory and a gel layer model showed that the gel layer on the membrane surface is not compressible and the specific cake resistance and gel layer concentration decrease with increasing temperature. An approximate value for the limiting (steady-state) flux was reported and it was found that the highest fluxes were obtained at the lowest initial water concentrations at fixed temperatures. In conclusion, dispersed glycerol can be successfully removed from raw FAME (untreated FAME) using a membrane separation system to meet the ASTM biodiesel fuel standards. The addition of water close to the solubility limit to the FAME mixture enables the formation of larger glycerol droplets and makes the separation of these droplets straightforward.

In the production of biodiesel via the transesterification of vegetable oils, purification to international standards is challenging. A key measure of biodiesel quality is the level of free glycerol in the biodiesel. In order to remove glycerol from fatty acid methyl ester (FAME or biodiesel), a membrane separation setup was tested. The main objective of this thesis was to develop a membrane process for the separation of free glycerol dispersed in FAME after completion of the transesterification reaction and to investigate the effect of different factors on glycerol removal. These factors included membrane pore size, pressure, temperature, and methanol, soap and water content. First, a study of the effect of different materials present in the transesterification reaction, such as water, soap, and methanol, on the final free glycerol separation was performed using a modified polyacrylonitrile (PAN) membrane, with 100 kD (ultrafiltration) molecular weight cut off for all runs at 25°C. Results showed low concentrations of water had a considerable effect in removing glycerol from the FAME. The mechanism of separation of free glycerol from FAME was due to the removal of an ultrafine dispersed glycerol-rich phase present in the untreated (or raw) FAME. The size of the droplets and the free glycerol separation both increased with increasing water content of the FAME. Next, three types of polymeric membranes in the ultrafiltration range with different molecular weight cut off, were tested at three fixed operating pressures and three operating temperatures (0, 5 and 25oC) to remove the free glycerol from a biodiesel reactor effluent. The ASTM standard for free glycerol concentration was met for the experiments performed at 25°C. The results of this study indicate that glycerol could be separated from raw FAME to meet ASTM and EN standards at methanol feed concentrations of up to 3 mass%. The process was demonstrated to rely on the formation of a dynamic polar layer on the membrane surface. Ceramic membranes of different pore sizes (0.05 µm (ultrafiltration (UF) range) and 0.2 µm (microfiltration (MF) range)) were used to treat raw FAME directly using the membrane separation set up at temperatures of 0, 5 and 25°C. The results were encouraging for the 0.05 µm pore size membrane at the highest temperature (25°C). The effect of temperature on glycerol removal was evident from its relation with the concentration factor (CF). Higher temperatures promoted the achievement of the appropriate CF value sooner for faster separation. Membrane pore size was also found to affect separation performance. A subsequent study revealed the effect of different variables on the size of the glycerol droplets using dynamic light scattering (DLS). A key parameter in the use of membrane separation technology is the size of the glycerol droplets and the influence of other components such as water, methanol and soaps on that droplet size. The effect of water, methanol, soap and glycerol on the size of suspended glycerol droplets in FAME was studied using a 3-level Box-Behnken experimental design technique. Standard statistical analysis techniques revealed the significant effect of water and glycerol on increasing droplet size while methanol and soap served to reduce the droplet size. Finally, a study on the effect of trans-membrane pressure (TMP) at different water concentrations in the FAME phase on glycerol removal using UF (0.03 µm pore size, polyethersulfone (PES)) and MF (0.1 and 0.22 µm pore sizes, PES) membranes at 25, 40 and 60°C was performed. Results showed that running at 25°C for the two membrane types produced the best results for glycerol removal and exceeded the ASTM and EN standards. An enhancement of glycerol removal was found by adding small amounts of water up to the maximum solubility limit in biodiesel. An increase in temperature resulted in an increase in the solubility of water in the FAME and less effective glycerol removal. Application of cake filtration theory and a gel layer model showed that the gel layer on the membrane surface is not compressible and the specific cake resistance and gel layer concentration decrease with increasing temperature. An approximate value for the limiting (steady-state) flux was reported and it was found that the highest fluxes were obtained at the lowest initial water concentrations at fixed temperatures. In conclusion, dispersed glycerol can be successfully removed from raw FAME (untreated FAME) using a membrane separation system to meet the ASTM biodiesel fuel standards. The addition of water close to the solubility limit to the FAME mixture enables the formation of larger glycerol droplets and makes the separation of these droplets straightforward.

Currently, 74% of cotton acres in the United States are planted with glyphosatetolerant varieties. The average glyphosate-tolerant cotton crop is treated with glyphosate 2.1 times each year in addition to other herbicides, insecticides, and fungicides. The primary objectives of this research were to: 1) describe the influence of glyphosate and pesticides commonly applied at or near the time of cotton planting on soil microbial activity and biomass; 2) study the effect of glyphosate on fluometuron degradation; 3) evaluate the response of Rhizoctonia solani to glyphosate and fluometuron; 4) study changes in glyphosate metabolism that occur as a result of repeated glyphosate applications; and 5) define shifts in the soil microbial community. Additionally, methods for accelerated solvent extraction (ASE) of fluometuron from soils were developed. In one experiment, the addition of glyphosate reduced C-mineralization in soils treated with fluometuron, aldicarb, or mefenoxam + PCNB formulations. However, in a second experiment, C-mineralization increased when glyphosate was applied with fluometuron relative to fluometuron applied alone. Accelerated solvent extraction was used in experiments which demonstrated that application of glyphosate with fluometuron increased the rate of fluometuron degradation in soil relative to fluometuron alone. When glyphosate was added to minimal medium, degradation of fluometuron by R. solani was reduced and less fungal biomass was produced. The total amount of 14C-glyphosate mineralized was reduced when glyphosate was applied 5 times relative to 1, 2, 3, or 4 times. Incorporation of 14Cglyphosate residues into soil microbial biomass was greater following five glyphosate applications than one application 3 and 7 days after application (DAA). Soil fatty acid methyl ester (FAME) profiles were altered by five glyphosate applications relative to one application. Additionally, FAMEs common to gram-negative bacteria were present in higher concentrations following five applications relative to 1, 2, 3, or 4 applications both 7 and 14 DAA. These studies indicated that: 1) glyphosate altered the soil microbial response to other pesticides; 2) fluometuron-degrading microorganisms in soil responded differently to glyphosate; 3) changes in the dissipation or distribution of glyphosate following repeated glyphosate applications were associated with changes in the structural diversity of the soil microbial community.