Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2017-02-21T18:17:11Z No. of bitstreams: 1 Diana Roberta Pereira Grandizoli.pdf: 22186247 bytes, checksum: eda73530f877f7998ed73ea7c0033e18 (MD5) / Made available in DSpace on 2017-02-21T18:17:11Z (GMT). No. of bitstreams: 1 Diana Roberta Pereira Grandizoli.pdf: 22186247 bytes, checksum: eda73530f877f7998ed73ea7c0033e18 (MD5) Previous issue date: 2016-12-19 / The present study sought to evaluate the influence of protease inhibitors on the bond strength of a self-etch adhesive system during hybrid layer formation in caries-affected dentin. The occlusal thirds of 80 permanent third molars were ground down to flat dentin surfaces. Dentinal caries were induced artificially by the microbial method. Groups were divided as follows: G1 (n=20), application of Clearfil SE Bond adhesive system (CL) alone; G2 (n=20), pretreatment with 2% chlorhexidine (CLX)+CL; G3 (n=20), pretreatment with sodium bicarbonate (BIC)+CL; G4 (n = 20), BI +CLX+CL. Bond strength was assessed immediately and at 6 months. Composite resin (Z350) build-ups were made on the dentin surfaces, and beam-shaped specimens with a cross-sectional area of 1 mm? were obtained. Microtensile bond strength testing was performed. Only adhesive or mixed-mode fractures were taken into account for calculation of bond strength. The results were submitted to the Kruskal-Wallis test (Student-Newman-Keuls). There was no significant difference on bond strength between the control, bicarbonate and chlorhexidine groups in the immediate test (p> 0.05). After 6 months, adhesive resistance fell for all groups. The control group had higher bond strength (p <0.05). The predominant fracture was of the adhesive type independent of the period evaluated. It can be concluded that after six months, there was decrease on bond strength for all groups. This reduction was greater in the groups in which the inhibitors were used / O objetivo desse trabalho foi avaliar a influ?ncia do bicarbonato de s?dio na resist?ncia adesiva durante a hibridiza??o da dentina cariada utilizando o sistema adesivo autocondicionante. Foram selecionados 80 terceiros molares permanentes, feita a remo??o do ter?o oclusal e superf?cies dentin?rias planas foram obtidas. A les?o de c?rie dentin?ria foi confeccionada atrav?s do m?todo microbiol?gico. Os grupos foram: G1 (n=20): aplica??o do sistema adesivo Clearfil (CL), G2 (n=20): aplica??o de clorexidina 2% (CLX) + CL, G3 (n=20): aplica??o de bicarbonato de s?dio (BI) + CL, G4 (n=20): BI + CLX + CL. A resist?ncia adesiva foi avaliada imediatamente e ap?s seis meses. Um bloco de resina composta Z350 foi constru?do em dentina. Cada bloco dente/adesivo/resina foi seccionado com disco diamantado acoplado ? m?quina de corte em planos paralelos obtendo-se corpos de prova em forma de palito, com ?rea de sec??o transversal de 1 mm?. Foi realizado teste de resist?ncia de uni?o por meio do teste de microtra??o. Foi considerada apenas fratura adesiva/mista para c?lculo da resist?ncia de uni?o. Os resultados foram submetidos aos teste de Kruskal-Wallis (Student-Newman-Keuls). N?o houve diferen?a significante na resist?ncia de uni?o entre os grupos controle, bicarbonato e clorexidina no teste imediato (p>0.05). Ap?s 6 meses, houve queda da resist?ncia adesiva para todos os grupos. O grupo controle apresentou maior resist?ncia de uni?o (p<0.05). A fratura predominante foi do tipo adesiva independente do per?odo avaliado. Pode-se concluir que ap?s seis meses, houve diminui??o na for?a de uni?o para todos os grupos. Essa redu??o apresentou-se maior nos grupos em que os inibidores foram utilizados.

La minéralisation induite par l'activité microbienne joue un rôle majeur dans le fonctionnement des écosystèmes passés et présents. Cette étude présente les données expérimentales de précipitation de CaCO3 à partir de cultures pures de deux types de bactéries anoxygéniques phototrophiques (APB) : Rhodovulum steppens A-20s haloalcaphilique et Rhodovulum sp. S-17-65 neutrophilique halophilique, ainsi que de cyanobactéries Gloeocapsa sp.. Ces bactéries représentent deux groupes importants d'organismes photosynthétiques depuis les temps les plus anciens jusqu'à nos jours. Dans ce contexte, cette thèse a pour objectif principal de caractériser les processus biologiques de précipitation de CaCO3 et d'évaluer l'existence d'un processus métabolique protégeant les bactéries étudiées contre la minéralisation de carbonates à leur surface. Pour cela, des expériences cinétiques, des mesures de potentiel zêta et d'adsorption de Ca à la surface bactérienne, couplées à des observations par Microscopie Electronique à Balayage (MEB), en Transmission (MET) et des analyses chimiques par émission et diffraction de rayons X (EDX et XRD) ont été menées. Les résultats de cette étude démontrent que les bactéries étudiées prennent une part active dans la précipitation de CaCO3 . Les mesures de potentiel zêta suggèrent l'existence d'un mécanisme de protection de la cellule pour les APB étudiées, basé sur le maintien métabolique d'une charge de surface plus positive à pH alcalin, préservant les bactéries actives de l'adsorption de Ca2+ et de la précipitation subséquente de carbonates à leur surface. L'existence d'un tel mécanisme n'est pas confirmée pour Gloeocapsa sp. Ainsi, deux mécanismes différents de nucléation de CaCO3 peuvent être mis en évidence : un premier mettant en jeu une sursaturation non-spécifique pour les bactéries anoxygéniques phototrophiques (APB), et un deuxième par nucléation spécifique au niveau de la membrane cellulaire pour les cyanobactéries Gloeocapsa sp..

<p>Diss. (sammanfattning) Umeå : Umeå universitet, 1994, härtill 5 uppsatser.</p> / digitalisering@umu

Conversion of natural gas and other light hydrocarbons via steam reforming is currently the major process for hydrogen production. However, conventional hydrogen production technologies are not cost effective and therefore, cost is the biggest impediment to use hydrogen in fuel cell applications. In order to optimize and overcome cost problems in hydrogen production, sorption and membrane enhanced reaction processes are the two novel technologies for in situ operation of reforming and removal of carbon dioxide. Adsorption of carbon dioxide onto activated hydrotalcite and activated soda, obtained from either trona or NaHCO3, had been studied using a stainless steel packed bed tubular reactor as a function of temperature. Adsorption of CO2 in the presence and absence of steam onto activated hydrotalcite was conducted in the temperature range of 400-527 oC, whereas sorption studies with activated soda were performed for 80 to 152 oC in the presence of steam. Also, two-parameter deactivation model was developed to justify the experimental data and predictions of the breakthrough curves by deactivation model indicated a good agreement with the experimental results. In order to obtain physical properties of the sorbents, untreated and calcined sorbents were characterized by using TGA, B.E.T (N2 adsorption), and Hg porosimetry techniques. When hydrotalcite was used as the sorbent, total adsorption capacity of the material reduced from 1.18 mol/kg to 0.66 mol/kg as the temperature was increased from 400 oC to 527 oC. On the other hand, activated soda exhibited a total adsorption capacity 1.15 to 0.68 mol/kg for a temperature change from 80 to 152 oC. For high temperature removal of CO2, hydrotalcite and its promoted forms (using K2CO3 or Na2CO3) are pretty good sorbents to be used in single step hydrogen production processes, such as SERP. On the other hand, activated soda could also be used for CO2 abatement of the effluent gas from the reformer only when the temperature is lowered enough to obtain efficient adsorption capacity within the multi-bed adsorbers.

The aims of this thesis were to: 1) develop a new method for the determination of interstitial pH at rest and during exercise in vivo, 2) systematically explore the effects of different ingestion regimes of 300 mg.kg-1 sodium citrate on blood and urine pH at rest, and 3) to combine the new interstitial pH technique with the findings of the second investigation in an attempt to provide a greater understanding of H+ movement between the extracellular compartments. The purpose of the first study was to develop a method for the continuous measurement of interstitial pH in vastus lateralis was successfully developed using microdialysis and 2,7-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF). To avoid the presence of an artificial alkalosis during exercise, it was necessary to add 25 mM HCO3- to the perfusate. The outlet of the probe was cut less than 10 mm from the skin and connected to a stainless steel tube completing the circuit to a microflow-through cuvette (8 fÝl) within a fluorescence spectrophotometer. This prevented the loss of carbon dioxide from the dialysate and any subsequent pH artefact. Interstitial pH was collected from six subjects before, during and after five minutes of knee-extensor exercise at three intensities 30, 50, and 70 W. Mean,,bSEM interstitial pH at rest was 7.38,,b0.02. Exercise reduced interstitial pH in an almost linear fashion. The nadir value for interstitial pH at 30, 50 and 70 W exercise was 7.27, 7.16 and 7.04, respectively. The lowest pH was obtained 1 min after exercise, irrespective of workload, after which the interstitial pH recovered in a nearly exponential manner. The mean half time of interstitial recovery was 5.2 min. The changes in interstitial pH exceeded the changes in venous blood pH. This study demonstrated that interstitial pH can be measured using microdialysis and that it is continuously decreased during muscle activity. The purpose of the second study was to establish an optimal ingestion regime for the ingestion of 300 mg.kg-1 of sodium citrate and maximise the alkalotic effect while minimising any side effects. Increasing the effectiveness of alkali ingestion may lead to further increases in muscle performance. Ingesting 300 mg.kg-1 sodium citrate at a rate of 300 mg.min-1 was identified as the optimal ingestion regime to maximise alkalosis at rest, which occurred 3.5 h post-ingestion. This was determined by monitoring eight human subjects ingesting 300 mg.kg-1 sodium citrate at five different rates, control (no ingestant), bolus, 300, 600 and 900 mg.kg.min-1 on five days separated by at least 48 hours. Sodium citrate was ingested in capsule form with water ad libitum, with the exception of bolus, which was combined with 400 ml less than 25 percent orange juice and consumed in less than 1 min. Arterialised blood (mean 71.3,,b3.5 mmHg) acid-base and electrolyte status was assessed via the withdrawal of ~5 ml of blood every 30 min across an eight hour duration, placed on ice and analysed within five minutes. No alkalotic difference was found between ingestion rates (mean 7.445,,b0.004, 7.438,,b0.004 and 7.442,,b0.004 for 300, 600 and 900 mg.min-1, respectively). All experimental ingestion regimes were associated with elevations in [HCO3-] (29.6, 29.7, 29.8, 29.9 and 26.3 mmol.l-1 for bolus, 300, 600, 900 and control, respectively). The 300 ingestion regime had the greatest impact on [H+], a 0.66 meq.l-1,,e10-8 change. Bolus ingestion (3.93,,b0.08 mmol.l-1) of sodium citrate had no effect on control (4.06,,b0.08 mmol.l-1) blood [K+], however, 300 mg.min-1 decreased blood [K+] (p less than 0.05). There was no effect of sodium citrate on blood [Cl-], but after 2.5 h blood [Cl-] was lower than pre-ingestion values (p less than0.05). All ingestion rates of sodium citrate increased (p less than 0.05) urine pH above control. This is the first study to investigate the effect of varying ingestion rates on acid-base status at rest in humans. The results suggest that ingesting sodium citrate in small doses in quick succession induce a greater blood alkalosis than the commonly practised bolus protocol. Using the interstitial pH technique described above and the optimal ingestion regime (300 mg.min-1) identified above, the final experiment was designed to assess the influence of sodium citrate ingestion on interstitial pH at both rest and during exercise. Five subjects ingested 300 mg.kg-1 sodium citrate at 300 mg.min-1 again in capsule form with water ad libitum. Prior to ingestion, each subject had a cannula placed into their cephalic vein and one microdialysis probe (CMA-60) inserted into their left thigh, orientated along the fibres of vastus lateralus. This probe was used for the measurement of pH as described above. At the end of this period, an exercise protocol required five subjects to perform light exercise (10 W) for 10 min, before starting an intense exercise period (~90-95% leg VO2peak) to exhaustion followed by a 15 min recovery period. Dialysate and blood samples were collected across all periods. Mean,,bSEM interstitial pH for placebo and alkalosis were 7.38,,b0.12 and 7.24,,b0.16, respectively. Sodium citrate ingestion was not associated with an interstitial alkalosis. An exercise induced acidosis was observed in the interstitium during placebo but not during alkalosis (p less than 0.05). Mean,,bSEM venous pH were 7.362,,b0.003 and 7.398,,b0.003 for placebo and alkalosis, respectively. Sodium citrate ingestion was not associated with a venous alkalosis. Sodium citrate ingestion was associated with an increase in mean,,bSEM venous [HCO3-] (placebo 25.5,,b0.2, alkalosis 28.1,,b0.2). This increase in the blood bicarbonate buffer system was not associated with an increase in time to exhaustion (placebo 352,,b71, alkalosis 415,,b171). This was the first study to investigate the effects of sodium citrate ingestion on interstitial pH. The results of this study demonstrated that an interstitial alkalosis does not ensue after alkali ingestion, however, it was associated with the lack of an exercise induced acidosis suggesting an improved pH regulation during exercise.

Nós determinamos a influência da alcalose e acidose metabólica induzida sobre o ritmo de prova, gasto energético e desempenho durante um teste contrarrelógio de ciclismo de 4 km (TCR). Após um estudo preliminar (N=7) determinando as doses ótimas de cloreto de amônio (NH4Cl), bicarbonato de sódio (NaHCO3) e placebo (carbonato de cálcio, CaCO3), 11 ciclistas amadores realizaram um TCR de 4 km 100 min após ingerirem 0,15 g·kg-1 de NH4Cl, 0,3 g·kg-1 de NaHCO3 ou 0,15 g·kg-1 de CaCO3 (desenho de medidas repetidas, contrabalançado e duplo-cego). Comparado com placebo, a ingestão de NaHCO3 resultou em uma alcalose sanguínea pré-exercício (pH: + 0,06 ± 0,04, [HCO3-]: + 4,7 ± 2,6 mmol?L-1, excess de base: + 4,6 ± 2,4 mmol?L-1, P<0,05), enquanto que o NH4Cl resultou em uma acidose sanguínea (pH: - 0,05 ± 0,04, [HCO3-]: - 5,5 ± 2,9 mmol?L-1, excesso de base: - 5,3 ± 2,5 mmol?L-1, P<0.05), com essas diferenças permanecendo durante todo o teste. Apesar de nenhum desconforto gastrointestinal severo, os participantes adotaram um ritmo de prova significativamente mais conservador em NH4Cl comparado com placebo e NaHCO3, que foi acompanhado por uma redução na taxa de gasto energético anaeróbio (~ -14 %, P<0,05) e menor trabalho anaeróbio total (~ -13 %, P<0,05). Consequentemente, o desempenho foi prejudicado em NH4Cl (~ -7 %) comparado com as demais condições (P<0,05). O lactato plasmático, VCO2 e a PetCO2 foram menores e a VE/VCO2 maior durante o TCR em acidose do que em placebo e alcalose (P<0,05). Entretanto, não houve diferença para essas variáveis entre placebo e NaHCO3 (P<0,05). A acidose metabólica induzida diminuiu o ritmo de prova e o metabolismo anaeróbio, além de prejudicar o desempenho durante um TCR de 4 km, independente de desconforto gastrointestinal / We determined the influence of induced metabolic alkalosis and metabolic acidosis on pacing, energy expenditure and performance during a 4-km cycling time trial (TT). After a preliminary study (N=7) determining the optimal ammonium chloride (NH4Cl), sodium bicarbonate (NaHCO3), and placebo (calcium carbonate, CaCO3) doses, 11 amateur cyclists performed a 4-km TT 100 min after ingesting either 0.15 g·kg-1 of body mass of NH4Cl, 0.3 g·kg-1 of NaHCO3 or 0.15 g·kg-1 of CaCO3 (double-blind, counterbalanced and repeated-measures design). Compared with placebo, the NaHCO3 ingestion resulted in a pre exercise blood alkalosis (pH: +0.06 ± 0.04, [HCO3-]: +4.7 ± 2.6 mmol?L-1, base excess: +4.6 ± 2.4 mmol?L-1, P<0.05), while NH4Cl resulted in a blood acidosis (pH: -0.05 ± 0.04, [HCO3-]: -5.5 ± 2.9 mmol?L-1, base excess: -5.3 ± 2.5 mmol?L-1, P<0.05), with these differences remaining throughout the trial. Despite no gastrointestinal distress, participants adopted a significant more conservative pacing in NH4Cl compared with placebo and NaHCO3, which was accompanied by a reduced anaerobic energy expenditure rate (~ -14 %, P<0.05) and lower total anaerobic work (~ -13 %, P<0.05). Consequently, the performance was less in NH4Cl (~ -7 %) compared with other conditions (P<0.05). Plasma lactate, VCO2 and PetCO2 were lower and the VE/VCO2 higher during the TT in acidosis than in placebo and alkalosis (P<0.05). However, there was no difference for these variables between placebo and NaHCO3 (P>0.05). Induced metabolic acidosis slows pacing, decreases anaerobic metabolism and impairs performance during a 4-km TT, independent of gastrointestinal distress

The aim of this study was to evaluate the efficiency of cleaning methods in removing pigment deposited on aesthetic brackets, after immersion in coffee. We selected 160 premolar brackets (80 monocrystalline and polycrystalline 80). The brackets were fixed on a glass blade and soon, thereafter, color measurement was performed using a spectrophotometer (T0). For each means of immersion, 80 brackets were selected (40 for each type of ceramic). Soon after staining (30 days of immersion), new color measurements were made (T1). Subsequently, the specimens were divided randomly into four groups for brushing, bleaching, blasting with sodium bicarbonate jet and sodium bicarbonate jet followed by bleaching. New color measurements were made after each cleaning method was used (T2). The color change of the brackets was evaluated according to two formulae, i.e., CIELAB and CIEDE2000. The differences between the average ΔE according to treatment, bracket, and solution were evaluated by linear regression analysis. The greatest staining was caused by coffee. The crystalline structure did not influence the color change. The methods with lower averages of ΔE for coffee were sodium bicarbonate jet followed by bleaching and bleaching, followed by the group that received brushing and sodium bicarbonate jet (both CIELAB as to CIEDE2000). The CIEDE2000 formula was more sensitive in detecting non-acceptable and perceptible differences in color when compared with the CIELAB formula. It was concluded that the most effective methods to remove pigment deposited on aesthetic brackets are sodium bicarbonate jet followed by bleaching and bleaching alone. / O objetivo desse estudo foi avaliar a eficiência dos métodos de limpeza na remoção de pigmentos depositados sobre bráquetes estéticos, após imersão em café. Foram selecionados 160 bráquetes (80 monocristalinos e 80 policristalinos) de pré-molares superiores. Os bráquetes foram fixados em uma lâmina de vidro e logo depois a mensuração de cor foi realizada com um espectrofotômetro (T0). Cada meio de imersão (café ou saliva) continha 80 bráquetes (40 para cada tipo de cerâmica). Logo após a coloração (30 dias de imersão) novas aferições foram feitas (T1). Posteriormente, os espécimes foram divididos randomicamente em 4 grupos: Grupo 1 Escovação; Grupo 2 Clareamento; Grupo 3 Jateamento com bicarbonato de sódio; Grupo 4 Jateamento com bicarbonato de sódio seguido de Clareamento. Novas aferições foram feitas depois de cada método de limpeza (T2). A variação da cor dos bráquetes foi avaliada de acordo com 2 fórmulas: CIELAB E CIEDE2000. As diferenças entre as médias de ΔE de acordo com o tratamento, braquete e solução foram avaliadas através de análise de regressão linear. O café promoveu maior manchamento. A estrutura cristalina não influenciou na alteração de cor. Os métodos com menores médias de ΔE, no café, foram o jateamento com posterior clareamento e o clareamento sozinho, seguido dos grupos que receberam jateamento e escovação (tanto para CIELAB quanto para CIEDE2000). A fórmula CIEDE2000 foi mais sensível em detectar diferenças de cor não-aceitáveis e perceptíveis quando comparado à fórmula CIELAB. Conclui-se que os métodos mais eficazes na remoção de pigmentos depositados sobre bráquetes estéticos são o jateamento com bicarbonato de sódio com posterior clareamento e o clareamento sozinho.

Made available in DSpace on 2016-12-06T17:06:50Z (GMT). No. of bitstreams: 1 Jardel Schlickmann.pdf: 828069 bytes, checksum: 28142f1471dd5fe8cbc06d71583812dd (MD5) Previous issue date: 2012-04-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The purpose of this study was to determine whether supplementation with sodium bicarbonate (NaHCO3) changes in performance during supramaximal cycling exercise (ESupra), the cardiorespiratory variables and subsequent isometric muscle strength (IMS). The study include 8 male subjects, physically active (23,0±4,01years; 54,69±6,51ml/kg/min-1). The subjects underwent an all out ESupra at 1min in cycle ergometer with load 0,075 kg/weight, after ingestion of solution 0,3g/kg with NaHCO3 or placebo (PLAC) with 0,045g/kg NaCl. After performed the IMS for the upper and lower limbs. The NaHCO3 did not affect the ESupra (497,45±52,47W) compared with PLAC (497,97±60,15W). There were no effects of the ESupra or NaHCO3 ingestion of the test IMS for the elbow flexors (NaHCO3 pre 38,4±6,6kgf and post 36,7±7,8kgf; PLAC pre 37,1±6,8kgf and post 36,2±8,0kgf), as well as for IMS the knee extensors (NaHCO3 pre 84,68±12,36kgf and after 80,28±11,88kgf; PLAC pre 87,04±16,38kgf and after 81,20±13,41kgf). In relation the physiological responses was observed a significant increase at the end of the ESupra only to VCO2 (4,93±0,47l/min) in the condition NaHCO3 compared to PLAC (4,44±0,28l/min). No differences were observed for VO2, VE and VCO2 at anytime during recovery. Lactate concentrations were differently to blood condition NaHCO3 compared to PLAC from the second minute after the ESupra. Before these results, it is likely that the increase in blood lactate concentration after ingestions of NaHCO3 was due to increased release of lactate exercised by muscle and/or by decreasing the absorption in other tissues, since not presented evidence of increased production during exercise (i.e. improved performance). Moreover, the largest peak value during the VCO2 in ESupra suggest a lager buffering H+ generated by supplementation with NaHCO3. Despite evidence to demonstrate the action of NaHCO3 on acid-base balance and transport of lactate the administration of the alkaloid did not favor the performance of 1min ESupra or the IMS of the upper and lower limbs in active individuals. / O objetivo deste estudo foi verificar se a suplementação com bicarbonato de sódio (NaHCO3) altera o desempenho durante exercícios supramáximos no ciclismo (ESupra), as variáveis cardiorrespiratórias, e a força muscular isométrica subseqüente. Participaram deste estudo 8 sujeitos do sexo masculino, fisicamente ativos (23,0±4,01anos; 54,69±6,51ml/kg/min-1). Os voluntários foram submetidos a um ESupra de 1min no cicloergômetro, com carga 0,075 kg/peso, após a ingestão de uma solução com 0,3g/kg NaHCO3 ou placebo (PLAC) com 0,045g/kg de NaCl. Em seguida realizaram os testes de força máxima isométrica (FMI) para os membros superiores e inferiores. O NaHCO3 não teve efeito sobre o desempenho no ESupra (497,45±52,47W) comparado ao PLAC (497,97±60,15W). Não foram observados efeitos do ESupra nem da ingestão do NaHCO3 no teste para FMI dos flexores do cotovelo (NaHCO3 pré 38,4±6,6kgf e pós 36,7±7,8kgf; PLAC pré 37,1±6,8kgf e pós 36,2±8,0kgf), como também para a FMI dos extensores do joelho (NaHCO3 pré 84,68±12,36kgf e pós 80,28±11,88kgf; PLAC pré 87,04±16,38kgf e pós 81,20±13,41kgf). Em relação às respostas fisiológicas foi observado um aumento significativo durante o ESupra apenas para o pico de VCO2 (4,93±0,47l/min) na condição NaHCO3 comparado com o PLAC (4,44±0,28l/min), sem diferenças significativas para essa variável durante a recuperação. Não foram observadas diferenças significativas para o VO2 e VE em qualquer momento durante a recuperação. As concentrações de lactato sanguíneo foram diferentes para condição NaHCO3 quando comparado com o PLAC à partir do segundo minuto após o ESupra até o final dos 30min de recuperação. Diante dos resultados encontrados, é provável que o aumento na concentração do lactato sanguíneo após ingestão de NaHCO3 seja decorrente da maior liberação do íon pela musculatura exercitada e/ou pela diminuição da absorção nos outros tecidos, uma vez que não foram apresentados indícios de uma maior produção durante o exercício (i.e. melhora na performance). Além disso, o maior valor de VCO2 pico durante o ESupra sugere um maior tamponamento do H+ gerado pela suplementação com NaHCO3. Apesar de demonstrarmos indícios da ação do bicarbonato sobre o equilíbrio acidobásico e no transporte de lactato, a administração do alcalóide não favoreceu o ESupra de 1min no ciclismo nem a força máxima isométrica de membros superiores e inferiores em indivíduos ativos.

Este estudo in vitro avaliou o efeito do bicarbonato de sódio 10% (BS) e do hidrogel de ascorbato de sódio 10% (AS) na resistência adesiva à microtração de uma resina composta unida à superfície de esmalte bovino clareado com peróxido de hidrogênio 35% (PH). Cento e vinte superfícies de esmalte vestibular com dimensões de 4mmX4mm de incisivos bovinos foram planificadas e separadas em cinco grupos: C - não clareado e restaurado; OI - clareado com PH e restaurado imediatamente; O7 - clareado com PH, armazenado por 7 dias em água destilada e restaurado; OBS - clareado com PH, BS 10% durante 5 min e restaurado; OAS - clareado com PH, AS 10% durante 15 min e restaurado. O gel de PH (Total Blanc Office, Nova DFL) foi aplicado duas vezes de 20 minutos em cada espécime e as restaurações foram confeccionadas com sistema adesivo restaurador (Natural Bond DE + Natural Look, Nova DFL). Após uma semana, os espécimes foram seccionados para obtenção de palitos com 1,00 mm2 de área média e submetidos ao teste de microtração em máquina de teste universal a 0,5mm/min, imediatamente e após 6 meses. As falhas foram avaliadas em estereomicroscópio digital (200x) e classificadas em: adesiva, coesiva em esmalte, coesiva em resina e mista. Os dados foram analisados por ANOVA a dois critérios e teste de Tukey para comparações múltiplas (p<0,05). Os valores médios de resistência adesiva (MPa ± DP; imediatamente / 6 meses) foram: C (24,22 ± 7,74 Ba / 20,13 ± 6,43 BCa); OI (18,29 ± 5,88 Ca / 25,85 ± 5,23 Ab); O7 (40,88 ± 7,95 Aa / 24,61 ± 7,83 ABb); OBS (19,95 ± 5,67 BCa / 15,94 ± 5,57 CDa); OAS (24,43 ± 6,43 Ba / 13,69 ± 5,58 Db). Das estratégias antioxidantes avaliadas após 7 dias, os grupos OAS e OBS não diferiram estatisticamente do grupo C, nem OBS diferiu estatisticamente do grupo OI. Nesse período de avaliação, somente o grupo O7 apresentou diferença significativa em relação aos demais grupos. Após 6 meses de envelhecimento, apenas O7 e OBS apresentaram desempenho semelhante estatisticamente ao grupo C. O percentual de falhas (7 dias / 6 meses) foi: adesiva (65,26% / 67,06%); coesiva em esmalte (14,74% / 24,71%); coesiva em resina (1,58% / 2,35%); mista (18,42% / 5,88%). Em função dos resultados apresentados, a estratégia mais segura é aguardar 7 dias após o clareamento para a realização de restaurações adesivas. Quando não for possível aguardar este tempo, a aplicação de bicarbonato de sódio 10% por 5 minutos sobre o esmalte clareado deve ser feita. / This \"in vitro\" study evaluated the effect of 10% sodium bicarbonate (SB) and 10% sodium ascorbate (SA) hydrogel on the composite resin microtensile bond strength of bleached bovine enamel with 35% hydrogen peroxide (HP). One hundred and twenty buccal enamel surfaces with dimensions of 4mmX4mm of bovine incisors were flattened and separated into five groups: C - not bleached and restored, OI - bleached with HP and immediately restored; O7 - bleached with HP, stored for 7 days in distilled water and restored; OBS - bleached with HP, 10% SB for 5 min and restored; OAS - bleached with HP, 10% SA for 15 min and restored. HP gel (Total Blanc Office, Nova DFL) was applied twice for 20 minutes on each specimen and the restorations were performed with an adhesive restorative system (Natural Bond DE + Natural Look, Nova DFL). After a week, the specimens were sectioned into sticks with a 1.00 mm2 average area and submitted to a microtensile test in a universal testing machine at 0.5 mm/min, immediately and after 6 months. The failures were evaluated in a digital stereoscope (200x) and classified as: adhesive, cohesive in enamel, cohesive in resin and mixed. Data was analyzed by two-way ANOVA and Tukey\'s test for multiple comparisons (p <0.05). The average values of the bond strength (MPa ± SD; immediately / 6 months) were: C (24.22 ± 7.74 Ba / 20.13 ± 6.43 BCa) OI (18.29 ± 5.88 Ca / 25.85 ± 5.23 Ab); O7 (40.88 ± 7.95 Aa / 24.61 ± 7.83 ABb), OBS (19.95 ± 5.67 BCa / 15.94 ± 5.57 CDa), OAS (24.43 ± 6.43 Ba / 13.69 ± 5.58 Db). Among the antioxidant strategies evaluated after 7 days, the OAS and OBS groups did not differ from group C and neither OBS group differed from the OI group. In the same evaluation period, only the O7 group presented a significant difference compared to the other groups. After 6 months of aging, only the O7 and OBS groups performed statistically similar to group C. The percentage of failures (7 days / 6 months) was: adhesive (65.26% / 67.06%); cohesive in enamel (14.74% / 24.71%); cohesive in resin (1.58% / 2.35%); mixed (18.42% / 5.88%). According to the results presented, the safety strategy is waiting 7 days after bleaching for the adhesive restorative procedures. When this waiting period is not possible, 10% sodium bicarbonate should be applied for 5 minutes on the bleached enamel.

Made available in DSpace on 2016-02-26T14:51:13Z (GMT). No. of bitstreams: 1 VivianeMariaOSFerreira.pdf: 589373 bytes, checksum: 61aa87cfad00f34ca4954e81485219c4 (MD5) Previous issue date: 2011-06-30 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The experiment was conducted to evaluate the effects of marination with alkaline solutions on sensory and physical characteristics of normal and PSE pork. In a commercial slaughterhouse was measured the pH of carcasses (n = 526) for 45 minutes after slaughter (pH45), classified them into PSE (pH45 <5.8) or normal (pH45 &#61619; 5.8). After 24 hours of chilling of carcasses, meat samples from the Longissimus dorsi muscle from 20 carcasses were collected and distributed in the treatments in a completely randomized design, in the 2x4 factorial arrangement, being two conditions (normal and PSE) and four solutions of marination (TC control without marination; TM1 sodium bicarbonate and sodium chloride solution (pH 8.02), TM2 sodium tripolyphosphate and sodium chloride solution (pH 10.34) and TM3 sodium bicarbonate, sodium tripolyphosphate and sodium chloride solution (pH 8.97). The samples were evaluated for pH, color (L * a * b *), purge loss (PP), exudate loss (PE), cooking loss (PPC), shear force (FC) and sensory attributes (tenderness, juiciness and flavor). There was no interaction between the condition of the meat and the marination solutions on these parameters. The PSE meat did not differ from normal meat as to final pH, however showed higher lightness, PP, PE, PPC and FC. The marination increased the pH of the meat, reduced the lightness, PE, PPC and FC and improved tenderness, juiciness and flavor. For most traits the best values were observed in meat marinated with a mixture of three salts (TM3), demonstrating the synergy between them. The marination with solutions containing chloride, bicarbonate, tripolyphosphate sodium was effective in improving the quality of pork, making PSE meat similar to normal fresh pork. / O experimento foi conduzido com o objetivo de avaliar os efeitos da marinação com soluções alcalinas sobre características físicas e sensoriais da carne suína normal e PSE. Em um abatedouro comercial aferiu-se o pH das carcaças (n = 526) aos 45 minutos após o abate (pH45), classificado-as em PSE (pH45<5,8) ou normais (pH45&#61619;5,8). Após 24 horas de resfriamento das carcaças, amostras de carne provenientes do músculo Longissimus dorsi de 20 carcaças foram coletadas e distribuídas nos tratamentos, em delineamento inteiramente casualizado, em arranjo fatorial 2x4, sendo duas condições (normal e PSE) e quatro soluções de marinação (TC controle sem marinação; TM1 solução de bicarbonato de sódio e NaCl (pH 8,02); TM2 solução de tripolifosfato de sódio e NaCl (pH 10,34) e TM3 solução de bicarbonato de sódio, tripolifosfato de sódio e NaCl (pH 8,97). As amostras foram avaliadas quanto ao pH, coloração (L*, a*, b*), perda por purga (PP), perda de exsudato (PE), perda de peso por cozimento (PPC), força de cisalhamento (FC) e atributos sensoriais (maciez, suculência e sabor). Não houve interação entre a condição da carne e os tratamentos de marinação para os parâmetros avaliados. Carnes PSE não diferiram de carnes normais quanto ao pH final, entretanto apresentaram maior luminosidade, PP, PE, PPC e FC. A marinação aumentou o pH da carne, reduziu a luminosidade, PE, PPC e FC e melhorou a maciez, suculência e sabor. Para a maioria das características avaliadas os melhores valores foram observados para carnes marinadas com a mistura dos três sais (TM3), evidenciando o sinergismo entre eles. A marinação com soluções contendo cloreto, bicarbonato e tripolifosfato de sódio foram eficientes em melhorar as características de qualidade da carne suína, tornando as carnes PSE semelhantes à carne normal in natura.