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This thesis is missing pages 87, 172 and 255. No other copies of the thesis have these pages. -Digitization Centre / This thesis examined the effects of exhaustive exercise on acid-base and metabolite status in the intracellular and extracellular compartments of two very different fish species: the active, pelagic rainbow trout, and the sluggish, benthic starry flounder. In both species, exhaustive exercise resulted in an acidosis in the extracellular compartment of mixed respiratory and metabolic origin. Despite the reduction in pHe, red blood cell pHi was well regulated, though more precisely in trout than in flounder. Catecholamines were mobilized into the blood after exercise in trout but not in flounder. Circulating catecholamines may play an important role in regulating red blood cell (RBC) pHi in trout after exercise. In trout, lactate appeared in the blood in excess of H+ ; the reverse pattern was observed in flounder. H+ appearance was similar in both species. Differential release of lactate from the muscle mass was apparently responsible for this discrepancy. After exhaustive exercise, both trout and flounder experienced a severe intracellular acidosis in the white muscle, as measured by 14c-DMO (5,5-dimethyl -2,4-oxazolidinenione) distribution. H+ and lactate were not produced in equimolar quantities, with H+ produced in excess of lactate. Muscle lactate and H+ production was about 3-fold lower in flounder than in trout. The muscle intracellular acid-base disturbance was corrected more rapidly in flounder (4-8h) than in trout (8-12h). In flounder, this occurred prior to , but in trout after , correction of the extracellular acidosis. In flounder, a more rapid correction of muscle metabolite status was associated with the more rapid correction of the intracellular acidosis. After exercise there was a reduction in the whole body extracellular fluid volume and expansion of the intracellular fluid volume, largely reflecting changes within the muscle. This fluid shift resulted in a general hemoconcentration. Exercise led to a transient increase in net H+ excretion in both trout and flounder. Negligible amounts of lactate were transferred to the water. In flounder, about 20% of the total H+ load produced passed through the extracellular space and was transiently stored in the water, which appeared to hasten correction of the intracellular acid-base disturbance. In contrast, in trout, a much smaller portion of the acid load (about 6%), though about the same absolute amount as in flounder, was transferred to the water. This appeared to expedite correction of the extracellular acidosis.The results of this thesis argue against a prominent role for the Cori cycle in the final disposition of the lactate burden produced during exercise. Instead, it is suggested that the bulk of the lactate was metabolized in situ, either by oxidation or glyconeogenesis. In flounder, this was almost the sole fate of lactate, as very little appeared in the blood space. In trout, a significant portion of the lactate was exported to the blood, which was taken up and metabolized by aerobic tissues. / Thesis / Doctor of Philosophy (PhD)

Effects of fat adaptation and NaHC0₃ supplementation on acid-base homeostasis were quantitated during repeated sprint exercise in horses. Contribution of strong ions ([SID]), Pco₂, and weak electrolytes ([A_tot]) to changes in plasma [H⁺] and the role of erythrocytes in acid-base balance were examined at rest and during exercise. Effects on plasma glucose and blood lactate [Lac⁻] concentrations due to sample handling were also assessed. During exercise, blood [Lac⁻] was higher when horses received NaHC0₃ compared to water prior to exercise (P=0.0024), and in fat adapted horses compared to horses fed a control diet (P=0.0240). Blood [Lac-] was higher in fat adapted horses given NaHC0₃ compared to other diet/treatment combinations (P=0.0276). Plasma [SID] was higher during exercise when horses were given NaHC0₃ compared to plain water (P=0.0054), which contributed to decreasing [H⁺] and increasing [HC0₃⁻] during exercise (P=0.0001). Plasma Pco₂ contributed less to increasing plasma [H⁺] during exercise in fat-adapted horses compared to horses fed the control diet (P=0.0282). Intraerythrocyte [SID] decreased (P=0.0160) and [Atod increased (P=0.0002) which contributed to increasing [H⁺] within the cell (P=0.0228). / Ph. D.

The fundamental study of Lewis acid/base interactions presented in this dissertation demonstrates the role of these interactions in adhesive phenomena. The model systems investigated were representative of real substrates and soft, viscoelastic adhesives where, in one case, favorable acid/base interactions were possible which were not possible in the other. Inverse gas chromatography (IGC) and Infrared spectroscopy (IR) techniques were used to analyze the model adhesive in terms of its acid/base nature. The results of both experiments indicated, through negative enthalpies of acid/base interaction with acidic solvents, that the model adhesive poly(2-ethyl hexyl methacrylate) (PEHMA) exhibits the properties of a Lewis base. The near quantitative agreement of the results from both experiments validate these methods of determining acid/base interactions in polymeric systems. Fitting the enthalpies for acid/base interaction to Drago’s and Gutmann’s models brought out the importance of the electrostatic component of the interactions investigated. Furthermore, they illustrated the need to expand the existing datasets beyond organo-meta1lic compounds, and include more common organic solvents. Results from X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM) analysis of the model substrate, grade 2 titanium, pretreated via chromic acid (CAA) or sodium hydroxide anodization (PSHA), confirmed that oxides of very similar topology can be produced. Indicator dye studies revealed the CAA-Ti had a surface pH of below 3.0 and the PSHA-Ti had a surface pH of above 8.0. Bonds constructed from these analyzed materials were tested in peel and both systems exhibited good adhesion. However, the bonds in which favorable interactions were possible demonstrated superior interfacial performance. This improvement was seen in the bond’s ability to resist adhesive (interfacial) failure at debond rates at which other bonds failed. When the test geometry was changed such that the stress intensity at the interface was increased, the bonds in which acid/base interactions were favorable supported a higher peel load. / Ph. D.

Estudaram-se as propriedades ácido base e de complexação com íons Cu(II) dos ácidos húmico (AH) e fúlvico (AF) extraídos de vermicomposto. O isolamento e a purificação foram realizados de acordo com o método descrito pela Sociedade Internacional de Substâncias Húmicas (IHSS). Estudaram-se as propriedades ácido-base por titulação potenciométrica em meio de KNO3 0,10 mol L-1 utilizando-se funções de Gran modificadas. Caracterizaram-se cinco classes de grupos ionizáveis, constatando-se predominância de grupos carboxílicos sobre grupos fenólicos e amínicos, especialmente para o AF, cuja acidez total foi maior do que a do AH. Estudaram-se as propriedades complexantes com íons Cu(II) nos pH 4, 5 e 6 por titulação potenciométrica com um eletrodo íon-seletivo para Cu(II), adotando-se os métodos de Scatchard e de regressão não linear com a equação de Langmuir para tratamento de dados. Em pH 5 e 6 caracterizaram-se duas classes de sítios de complexação, enquanto em pH 4, apenas uma classe foi caracterizada. De maneira geral, a estabilidade e a capacidade de complexação aumentaram com o pH, indicando a competição de prótons pelos sítios de complexação. Os resultados indicam maior estabilidade e capacidade para a complexação com AH em relação ao AF. Esta tendência foi verificada por funções diferenciais de equilíbrio diferenciais aplicadas em baixos graus de ocupação de sítios. / Acid base and complexation with Cu(II) ions were studied for humic (AH) and fulvic (AF) acids extracted from vermicompost. The isolation and purification was performed according the procedure described by the International Humic Substances Society (IHSS). The acid base properties were studied by potentiometric titration in 0,10 mol L-1 KNO3 using modified Gran functions. Five classes of ionizable sites were characterized, showing a predominance of carboxylic over phenolic and aminic groups, especially for AF, which has total acidity larger than the one determined for AH. Complexing properties with Cu(II) ions were studied by potentiometric titration at pH 4, 5 and 6 using Cu(II) ion-selective electrode. Data treatment was performed using the Scatchard method, as well as non-linear regression with the Langmuir equation. At pH 5 and 6, two classes of binding sites were characterized, but at pH 4 only a single complexing site was characterized. Stability and capacity increased with pH, suggesting competition of protons by the binding sites. The results indicate larger stability and capacity for complexation with AH in comparison with AF. This trend was also verified by differential equilibrium functions at low degree of site occupation.

Estudaram-se as propriedades ácido base e de complexação com íons Cu(II) dos ácidos húmico (AH) e fúlvico (AF) extraídos de vermicomposto. O isolamento e a purificação foram realizados de acordo com o método descrito pela Sociedade Internacional de Substâncias Húmicas (IHSS). Estudaram-se as propriedades ácido-base por titulação potenciométrica em meio de KNO3 0,10 mol L-1 utilizando-se funções de Gran modificadas. Caracterizaram-se cinco classes de grupos ionizáveis, constatando-se predominância de grupos carboxílicos sobre grupos fenólicos e amínicos, especialmente para o AF, cuja acidez total foi maior do que a do AH. Estudaram-se as propriedades complexantes com íons Cu(II) nos pH 4, 5 e 6 por titulação potenciométrica com um eletrodo íon-seletivo para Cu(II), adotando-se os métodos de Scatchard e de regressão não linear com a equação de Langmuir para tratamento de dados. Em pH 5 e 6 caracterizaram-se duas classes de sítios de complexação, enquanto em pH 4, apenas uma classe foi caracterizada. De maneira geral, a estabilidade e a capacidade de complexação aumentaram com o pH, indicando a competição de prótons pelos sítios de complexação. Os resultados indicam maior estabilidade e capacidade para a complexação com AH em relação ao AF. Esta tendência foi verificada por funções diferenciais de equilíbrio diferenciais aplicadas em baixos graus de ocupação de sítios. / Acid base and complexation with Cu(II) ions were studied for humic (AH) and fulvic (AF) acids extracted from vermicompost. The isolation and purification was performed according the procedure described by the International Humic Substances Society (IHSS). The acid base properties were studied by potentiometric titration in 0,10 mol L-1 KNO3 using modified Gran functions. Five classes of ionizable sites were characterized, showing a predominance of carboxylic over phenolic and aminic groups, especially for AF, which has total acidity larger than the one determined for AH. Complexing properties with Cu(II) ions were studied by potentiometric titration at pH 4, 5 and 6 using Cu(II) ion-selective electrode. Data treatment was performed using the Scatchard method, as well as non-linear regression with the Langmuir equation. At pH 5 and 6, two classes of binding sites were characterized, but at pH 4 only a single complexing site was characterized. Stability and capacity increased with pH, suggesting competition of protons by the binding sites. The results indicate larger stability and capacity for complexation with AH in comparison with AF. This trend was also verified by differential equilibrium functions at low degree of site occupation.

Notre travail constitue une analyse objective de l'évolution des connaissances relatives aux acides et aux bases construites par les élèves et les étudiants suite aux enseignements reçus et en particulier lors de la transition lycée-université. Les travaux antérieurs avaient pour objectif de faire ressortir les conceptions alternatives et les difficultés dans la compréhension de ces concepts que sont susceptible de rencontrer les élèves et étudiants concernés par notre étude. Notre cadre théorique s’articule autour de la transposition didactique, de rapport au savoir et des relations entre les phénomènes et leur modélisation dans l'enseignement de la chimie. D’où l’apparition des questions et hypothèses de recherche. Suite aux analyses effectuées, il en résulte un manque de rigueur dans l’utilisation du vocabulaire et/ou du formalisme conduisant parfois à la présentation de modèles hybrides susceptibles d’induire chez les élèves ou les étudiants des conceptions alternatives ou de conduire à des difficultés de compréhension. Plusieurs conceptions alternatives et difficultés résultent aussi de la non mise en relation claire et explicite par les enseignants des trois registres de la chimie, macroscopique, microscopique et symbolique. Enfin, la transition lycée-université ne remplit pas les conditions favorables à un approfondissement conceptuel des savoirs vus en terminale, elle permet tout au plus leur réappropriation par certains. / This work consisted of a complete longitudinal study of the didactic transposition relative to the acids and base conceptual field from the upper-secondary school to the first university year in Tunisia. A literature review led to the formulation of the research questions and hypotheses and to the choice of a analysis theoretical framework, the anthropological theory of didactics of Chevallard and the link between phenomena and their modelling in the chemistry education. Having made a historical analysis of the reference knowledge construction we realized a study of the institutional relationship of the pupils/students with the objects of knowledge for the various levels of education. We found a lack of strictness in the use of the vocabulary and\or formalism sometimes leading to the presentation of hybrid models susceptible to induce pupils/ student’s alternative conceptions or to lead to difficulties of understanding. We put in evidence that the tasks and techniques which repeat during the various levels of education concern the pH calculations and titrations. In the taught knowledge we have identify some inaccuracies and some inadequacy which can be at the origin of certain difficulties or alternative conceptions. Concerning the evolution of the knowledge learnt further to the successive educations, we put in evidence that the education concerning the acid and base concepts from the second year of upper-secondary school (grade 10) to the first university year leads gradually to the passage of a "phenomenological model" to a "symbolic model", then to a " pithy formula model", but little to the integration of the Bronsted scientific model. We also showed that it is in the difficulty to linking the three registers of chemistry, macroscopic, microscopic and symbolic, that lives the main difficulties encountered by pupils/students and their tendency to have recourse to use alternative reasoning’s. Besides, the conceptions and the identified alternative reasoning’s seem due to a lack of strictness in the presentation of the taught knowledge contents. Finally, if we consider the conceptual evolution during the secondary school-university transition, we put in evidence that this transition does not perform the favourable conditions to a conceptual analysis of the knowledge’s seen in grade 12, it allows, at the most, to their another appropriation by some. Propositions for improve this evolution were formulated.

No presente trabalho focalizou-se a atenção nas propriedades de substâncias húmicas, em particular a fração de ácido húmico (AH), o qual foi obtido de duas fontes, sendo uma comercial e outra isolada de sedimentos do Rio Tietê, coletados no reservatório de Barra Bonita (SP). O isolamento do AH do sedimento foi realizado segundo o procedimento proposto pela Sociedade Internacional de Substâncias Húmicas (S.I.S.H.). Ambas amostras foram caracterizadas em paralelo através de análise elementar, absorção molecular no visível (razão E4/E6) e infravermelho e teores de cinzas. As propriedades ácido-base das amostras foram estudadas por titulação potenciométrica, adotando-se o modelo de distribuição de sítios discretos, empregando-se funções de Gran modificadas para tratamento dos dados. Foi possível caracterizar seis classes de grupos tituláveis em força iônica 0,1 (NaCI), com pKa entre 3 e 10. Constatou-se maior contribuição de grupos carboxílicos (grupos titulados com pKa < 7) do que fenólicos e amínicos em ambas amostras. Os resultados foram comparados com os métodos clássicos do acetato de cálcio e barita, assim como por titulação condutométrica. Estudou-se as propriedades de complexação dos AHs com íons Cu2+,Pb2+, Cd2+ e Zn2+ através de titulação potenciométrica com eletrodo íon-seletivo de membrana sólida para o CU2+ e de amálgama para os demais íons. Constatou-se a seguinte ordem de estabilidade para os complexos formados com ambos AHs: log K AH-Cu > log K AH-Pb > log K AH-Cd aproximadamente igual a log K AH-Zn. Quanto a capacidade de complexação (Cc), observou-se que CcPb > CcCu > CcCd aproximadamente igual a CcZn. / The aim of the present work was to study the humic substances, with emphasis to the humic acid (HA) fraction isolated from sediments of the Tietê River, collected at the Barra Bonita reservoir. The extraction of the humic acid was performed according to the procedure proposed by the International Humic Substances Society (I.H.S.S.). A commercial humic acid from Aldrich was studied in parallel. Both HA samples were characterized by elemental analysis, molecular absorption in the visible (E4/E6 ratio) and infrared regions, and ash contents. The acid-base properties of both humic acids were studied by potentiometric titrations, adopting the discrete site distribuition model and the modified Gran functions for data fitting. Six classes of titratable groups were characterized in 0,1 mol.L-1 (NaCI) ionic medium, with pKa values between 3 and 10. The sum of carboxylic groups (titratable groups with pKa < 7) was greater than the sum of aminic and phenolic groups for both humic acids. These results were compared with those provided by classical methods such as baryta adsorption and calcium acetate, as well as condutometric titration. The complexing properties were studied with regard to Cu2+,Pb2+, Cd2+ and Zn2+, by potentiometric titration with solid membrane copper ion-selective electrode and amalgam electrodes for the other ions. The following stability was observed for both HAs complexes: log KHA-Cu > log KHA-Pb > log KHA-Cd approximately equal to log KHA-Zn. With regard the complexing capacity (Cc),the following order was observed: CcPb > CcCu > CcCd approximately equal to CcZn.

O estudo avaliou os efeitos agudos da Ang-(1-7) na reabsorção de bicarbonato (JHCO3-) no túbulo proximal cortical de rato, in vivo, medindo o pH intratubular pelo microeletródio sensível a H+. O JHCO3- controle é 2,84 ± 0,08 nmol. cm-2. s-1 (49), a Ang-(1-7; 10-12 ou 10-9 M) o reduz (35 ou 61 %) e a Ang-(1-7; 10-6 M) o eleva (56 %). A inibição do receptor Mas (por A779) eleva o JHCO3- (30 %), abole o efeito inibidor da Ang-(1-7), mas não afeta seu efeito estimulador. A inibição do NHE3 (por S3226) diminui o JHCO3- (45 %), não altera o efeito inibidor da Ang-(1-7), mas transforma seu efeito estimulador em inibidor. A concentração de cálcio citosólico ([Ca2+]i), medida pelo FURA-2-AM, controle é 100 ± 2,47 nM (35) e a Ang-(1-7; 10-12, 10-9 ou 10-6 M) a aumenta (152, 103 ou 53 %) transientemente (3 min). A inibição do receptor Mas aumenta a [Ca2+]i (26 %), mais inibe o efeito estimulador de todas as doses de Ang-(1-7). Os resultados indicam que o efeito bifásico dose-dependente da Ang-(1-7) sobre o JHCO3- no túbulo proximal é via receptor Mas e isoforma NHE3 e sugerem estimulação desse trocador por moderado aumento da [Ca2+]i na presença de Ang-(1-7; 10-6 M) e sua inibição por pronunciado aumento da [Ca2+]i na vigência de Ang-(1-7; 10-12 ou 10-9 M). / The action of Ang-(1-7) on bicarbonate reabsorption (JHCO3-) was evaluated in vivo middle proximal tubule of rat kidney, using H ion-sensitive microelectrodes. The control JHCO3- is 2,84 ± 0.08 nmol. cm-2. s-1 (49), Ang-(1-7; 10-12 or 10-9 M) decreases it (35 and 61 %) but Ang-(1-7; 10-6 M) increased it (56 %). A779 (an Ang-(1-7) receptor Mas antagonist) increases the JHCO3- (30 %), prevents the inhibitory effect of Ang-(1-7) and does not affect the stimulatory effect of Ang-(1-7). S3226 (10-6 M; an inhibitor of NHE3) decreases the JHCO3- (45 %), does not affect the inhibitory effect of Ang-(1-7) and changes its stimulatory effect on an inhibitory effect. The control cytosolic free calcium ([Ca2+]i), monitored by FURA-2-AM, is 100 ± 2,47 nM (35) and Ang-(1-7; 10-12, 10-9 or 10-6 M) causes a transient (3 min) increase of it (152, 103 or 53 %). A779 increases the [Ca2+]i (26 %) but impaired the stimulatory effect of Ang-(1-7). Our results indicate the biphasic dose-dependent effect of Ang-(1-7) on JHCO3- in proximal tubule is mediated via Mas receptor and NHE3 and are compatible with stimulation of this exchanger by a moderate increase in [Ca2+]i in the presence of Ang-(1-7, 10-6 M), and its inhibition by large increase in [Ca2+]i with Ang-(1-7, 10-12 or 10-9 M).