Ingesting carbohydrate (CHO) before and during prolonged steady-state exercise can significantly improve the endurance capacity (time to exhaustion) of adolescents. This knowledge, combined with current understanding of the physiological and metabolic responses of young people to prolonged steadystate exercise, as well as awareness of youth team games participation statistics, suggests CHO ingestion before and during team games exercise may be beneficial for adolescent team games players. However, research in this area has not been conducted, presenting a notable gap in the paediatric exercise science literature. This thesis described three studies with the aim of investigating the influence of CHO ingestion immediately before, and during, prolonged intermittent, high-intensity exercise on the endurance capacity, sprint performance, and physiological responses of adolescent team games players. The studies investigated a CHO-electrolyte (CHO-E) solution, solutions of differing CHO concentration ([CHO]), and CHO in the form of a gel in trained 12-14 year old soccer, rugby, and field hockey players during a modified Loughborough Intermittent Shuttle Test (LIST). Study 1 (n = 15) reported a significant 24.4% enhancement of intermittent endurance capacity with ingestion of a 6% CHO-E solution compared with a placebo (PLA, 5.1 ± 1.8 vs. 4.1 ± 1.6 min, P < 0.05, r = 0.51), with distance covered also significantly greater in the CHO trial (851 ± 365 vs. 694 ± 278 m, P < 0.05, r = 0.52). No significant influence of CHO was found for mean sprint times (P = 0.35, r = 0.27) or physiological response except at exhaustion, where peak heart rate was significantly greater in the CHO trial (P < 0.05, r = 0.55). Study two (n = 7) found a significant influence of [CHO] on intermittent endurance capacity, with a 6% solution increasing intermittent endurance capacity by 34.1% compared with a 10% solution (5.5 ± 0.8 vs. 4.1 ± 1.5 min, P < 0.05, r = 0.76). No significant difference was observed between the 2% (4.8 ± 1.2 min) and the 6% (P = 0.10, r = 0.63), or the 2% and the 10% (P = 0.09, r = 0.63) solution. Distance covered was significantly greater with the 6% solution compared with the 10% solution (931 ± 172 vs. 706 ± 272 m, P < 0.05, r = 0.76), but was not significantly different compared with the 2% solution (811 ± 230 m, P = 0.09, r = 0.63) or between the 2% and 10% solutions (P = 0.11, r = 0.61). Carbohydrate concentration did not significantly influence mean sprint times (P = 0.38, r = 0.42) or physiological response. Study three (n = 11) reported a significant 21.1% enhancement in intermittent endurance capacity with ingestion of a CHO gel, isoenergetic to the 6% CHO-E solution used in studies 1 and 2, compared with a PLA gel (4.6 ± 2.0 vs. 3.8 ± 2.4 min, P < 0.05, r = 0.67). Distance covered was also significantly greater in the CHO trial (787 ± 319 vs. 669 ± 424 m, P < 0.05, r = 0.57). No influence of the CHO gel was observed on mean sprint times (P = 0.33, r = 0.31) or physiological response. This thesis reports a significant positive influence of CHO ingestion on the intermittent endurance capacity of adolescent team games players during prolonged intermittent, high-intensity exercise. Ingestion of a 6% CHO-E solution was more beneficial than a PLA solution and a 10% CHO-E solution. When compared to a PLA gel, CHO gel ingestion was analogous in efficacy to a 6% CHO-E solution. Carbohydrate ingestion did not significantly influence sprint performance. The influence of CHO on the physiological responses of adolescent team games players to prolonged intermittent, high-intensity exercise was minimal, with the only reported effect being a significantly greater HR at exhaustion in study 1. This thesis has provided evidence to support the use of CHO before and during team games in adolescent team games players, begun to formulate guidelines for CHO ingestion by adolescent team games players, and provided a robust foundation for further study in this field.

Class of 2010 Abstract / OBJECTIVES: The purpose of this study was to determine the incidence of contrast induced nephropathy (CIN) for patients receiving a pre-hydration regimen to prevent CIN. METHODS: This was a descriptive retrospective chart review study. Charts were reviewed from Banner Boswell Medical Center and a nephrologist’s office in Sun City, Arizona. RESULTS: There were a total of 12 patients included in the study. The population after completetion of chart reviews consisted of 6 male patients and 6 female patients. The age range of the patients included was 54-90 years old. CIN occurred in zero of the twelve patients. Half of the 12 patients had a decrease in serum creatinine ranging from 0.1- 0.6 mg/dL, 24-48 hours post-diagnostic procedure. CONCLUSIONS: There was no incidence of CIN after the 12 patients received the specific protocol. This study demonstrates the potential for this regimen as a pre-hydration option for individuals undergoing procedures in which radiocontrast is necessitated. A prospective observational study with a larger sample size would be warranted to determine the safety and efficacy of the protocol and increase the validity of the results of this descriptive study.

G-protein–coupled receptors are the largest superfamily in the human genome, and involved in critical cellular signaling processes in living cells. Protein structural fluctuations are the key for GPCR function that is driven and modulated by a variety of factors that are not well understood. This dissertation focusses on understanding the activation of GPCRs using the visual receptor, rhodopsin as the prototype. Rhodopsin is an ideal candidate for this study, as it represents the largest class of GPCRs, and is known to demonstrate more noticeable structural changes upon activation compared to the other GPCRs. What structural fluctuations occur, the role of water, and how the retinal cofactor regulates the protein dynamics during rhodopsin activation are specific research problems addressed in this work. Hypothesizing an ensemble activation mechanism, experiments were conducted using a variety of techniques to probe structural and dynamical fluctuations of rhodopsin in native membranes, as well as in membrane mimetics such as detergent micelles. Time-resolved wide-angle X-ray scattering (TR-WAXS), small-angle neutron scattering (SANS), quasielastic neutron scattering (QENS), and electronic spectroscopy are among the prominent techniques used to gain insights into the photo-intermediates that are key to understanding the rhodopsin activation process. The small-angle neutron scattering (SANS) experiments revealed a volumetric expansion of the protein molecule upon photoactivation of rhodopsin. Electronic spectroscopy together with the differential hydration study revealed the crucial role of water in rhodopsin signaling process and signal amplification by water. The quasielastic neutron scattering study conducted on powdered rhodopsin probed the changes in the local dynamics that are regulated by the retinal cofactor of the rhodopsin molecule. The increased local steric crowding in the ligand-free opsin is consistent with collapsing of the apoprotein structure in the absence of the retinal chromophore leading to inactive opsin conformation. Finally, a time-resolved wide-angle X-ray scattering study was conducted using the X-ray free electron laser at the SLAC national laboratory to probe the early structural fluctuations in rhodopsin photoactivation. The preliminary pump-probe experiments conducted on rhodopsin in CHAPS detergent micelles revealed a light-triggered protein quake that occurs during the early activation stages of rhodopsin photoactivation. Thus the protein fluctuations underlying the GPCR function are revealed by neutrons, X-rays, and other photons in a combined implementation of both spectroscopic and scattering techniques as applied to the investigation of rhodopsin activation.

A água é o principal componente do ser humano, a falta desse elemento pode resultar em consequências negativas, como o comprometimento do funcionamento de órgãos e sistemas ou até a morte. Considerando a hidratação um hábito essencial para a saúde do corpo, qual a sua relação com a saúde vocal? O objetivo do presente estudo foi verificar se as mudanças no estado de hidratação sistêmica dos indivíduos influenciam na qualidade vocal antes e após o uso contínuo da voz. Participaram desse estudo 13 indivíduos do sexo masculino, estudantes da Escola de Engenharia de São Carlos da Universidade de São Paulo USP, com média de idade de 21,31 ± 2,10 anos e IMC de 22,44 ± 2,04 kg/\'M POT.2\'. Os participantes foram submetidos a três avaliações não consecutivas em diferentes estados de hidratação sistêmica. Avaliação 1, hidratados, para tanto, os indivíduos foram orientados a ingerir a quantidade de 3,0 litros de água no dia anterior a avaliação e 1,5 litros na manhã do dia da avaliação. Avaliação 2, desidratados, os indivíduos foram orientados a não ingerir água ou líquidos das 22:00 horas do dia anterior até a manhã do dia da avaliação. Avaliação 3, desidratação por exercício físico, a orientação de ingestão de água foi igual a Avaliação 2 e para induzir ainda mais a desidratação, os indivíduos foram submetidos a exercício em esteira por 40 minutos. Nas 3 avaliações os procedimentos foram: gravação da voz em computador, para posteriores avaliações acústica e perceptivo-auditiva da voz; e coleta de urina, para verificação dos estados de hidratação. Para a análise da urina foram utilizados dois métodos: a gravidade específica e coloração da urina. Para a análise acústica da voz foi utilizado o programa MDVP com as medidas da frequência fundamental, jitter, shimmer e proporção harmônico ruído utilizando-se a vogal /a/ sustentada. A avaliação perceptivo-auditiva da voz foi realizada por uma fonoaudióloga especialista em voz, por meio das gravações da contagem de números. Os resultados da análise da urina confirmaram os diferentes estados de hidratação sistêmica e apresentaram forte correlação entre os métodos da gravidade e da coloração da urina. Os resultados da análise acústica indicaram valores de jitter acima da referência na desidratação tanto antes como após o uso contínuo de fala; maior valor médio de jitter antes da leitura no 9 estado de desidratação; aumento da frequência fundamental após leitura no estado de desidratação. Não foram observadas alterações significativas nas medidas de shimmer e na proporção harmônico ruído. A avaliação perceptivo-auditiva apontou melhora da qualidade vocal após leitura no estado de hidratação. As mudanças vocais observadas nos diferentes estados de hidratação sistêmica confirmaram que a hidratação traz benefícios para a voz. / Water is the main component of the human being, the lack of this element can result in negative consequences such as impaired functioning of organs and systems or even death. Considering hydration as an essential habit to the health of body, which is its relationship with vocal health? The aim of this study was to determine whether changes in systemic hydration status of individuals can influence the voice quality before and after continuous use of voice. In this study, 13 male students of the School of Engineering of the University of São Paulo-USP, with a average age of 21.31 ± 2.10 years and BMI 22.44 ± 2.04 kg/\'M POT.2\'. The participants were subject to three, nonconsecutive assessments, at different status of systemic hydration: Evaluation 1, hydrated, the subjects were instructed to drink 3 liters of water the day before the evaluation and 1.5 liters in the morning of the evaluation. Evaluation 2, dehydrated, subjects were instructed not to drink water or liquids from 10pm the day before until the morning of the evaluation. Evaluation 3, dehydration by physical exercise, the orientation of water intake was equal to evaluation 2 and to induce further dehydration, the subjects were subjected to a treadmill exercise during 40 minutes. At the 3 evaluations, the procedures were: voice recording on computer for subsequent acoustic and auditive-perceptual evaluations and urine collect to verify the hydration levels. For the urine analysis were used two methods: the specific gravity of the urine and its color. For the acoustic voice analysis the program MDVP was used to measures of fundamental frequency, jitter, shimmer and harmonic noise using the sustained vowel /a/. The auditive-perceptual evaluation of voice was performed by a Speech Therapist specialized in voice studies, through the recordings of the counting numbers. The results of urine analysis confirmed the different levels of hydration and both specific gravity and color of the urine showed a strong correlation. The results of acoustic analysis indicated jitter values above the reference in the dehydration both before and after reading, higher average jitter value before reading in the state of dehydration, also increasing fundamental frequency. There were no significant changes in measures of shimmer and harmonic noise. 11 The perceptual assessment of voice quality showed a improvement after reading during the state of hydration. Vocal changes observed in the different states of systemic hydration confirmed that hydration is beneficial to the voice.

The synthesis of high value acrylic monomers is currently done industrially via cyanohydrin hydration using concentrated acids, resulting in large quantities of useless byproducts. This current process is energy intensive and lacks atom economy; therefore, alternative cyanohydrin hydration strategies are under investigation. Ideally, cyanohydrin hydration would be done using organometallic nitrile hydration catalysts. Cyanohydrin hydration with these catalysts is challenging, because it needs to be done at low temperatures and under acidic conditions to reduce cyanohydrin degradation and catalyst poisoning with cyanide. This dissertation describes the reactivity of [Ru(#951; / 10000-01-01

Acrylic monomers are important materials that represent a large portion of the economy. The current industrial synthesis hydrates cyanohydrins with sulfuric acid, a process which results in large amounts of waste and significant energy costs. A transition metal catalyzed, acid free hydration of cyanohydrins would be beneficial from both economic and environmental standpoints. However, this reaction is challenging, as many catalysts are poisoned by the cyanide released when cyanohydrins degrade. Therefore the development of a catalyst that is resistant to cyanide poisoning is the ideal method to circumvent these difficulties. This dissertation describes several cyanohydrin hydration catalysts, with an emphasis on nanoparticle catalysts. These are at the interface between the homogeneous and heterogeneous catalysts that have been explored previously for this reaction. Chapter I surveys previous studies on nanoparticle catalysts for nitrile hydration and their implications for the hydration of cyanohydrins. Chapter II reports on the homogeneous platinum catalysts [PtHCl(P(NMe2)3)2] and [PtH2(P(NMe2)3)2], exploring secondary coordination sphere effects to enhance nitrile hydration. Chapter III describes another example of this type of complex, [PtH2(P(OMe)3)2], that forms catalytically active nanoparticles under reaction conditions. Explorations of the reactivity of this catalyst with nitriles and cyanohydrins are also described in this chapter. Chapter IV investigates a silver nanoparticle catalyst with a water soluble phosphine (1,3,5-triaza-7-phosphaadamantane) ligand for its activity towards the hydration of nitriles and cyanohydrins. The results of the degradation of the nanoparticles in the presence of cyanide are also described. Chapter V reports on the preparation and examination of a solid supported nickel catalyst for cyanohydrin hydration. Finally, Chapter VI describes how these investigations have made progress towards the development of a cyanide resistant nitrile hydration catalyst. This dissertation includes previously published and unpublished co-authored material. / 2015-09-29

No presente trabalho, realizado com hemoproteínas na forma de pó, o efeito da hidratação foi observado através de espectroscopia fotoacústica. Amostras de carboxi-hemoglobina e carboxi-mioglobina mantidas em diferentes ambientes de umidade relativa (UR), mostraram variações em seus espectros na região da banda de Soret. Para amostras mantidas em baixa hidratação característico do derivado carboxi, em alta hidratação (acima de aproximadamente 90% UR) o espectro era característico do derivado carboxi e na região intermediária o espectro era de uma mistura dos dois derivados. Essa mudança de ligante observada em alta hidratação pode ser explicada supondo que a proteína tem flexibilidade e atinge um estado conformacional que possibilita a entrada e saída do ligante. Em baixa hidratação a estrutura da proteína é rígida e tal que o acesso ao grupo heme está fechado, impossibilitando a troca do ligante. Essa explicação é coerente com vários resultados experimentais que indicam a existência de duas estruturas para essas hemoproteínas em solução / At the present work accomplished with powder of hemoproteins, the hydration effect was observed through photoacoustic spectroscopy. Samples of caroxyhemoglobin and carboxymyglobin kept at different relative humidity (RH) environments, showed variations in their spectra in the Soret bad region. For the samples which were kept at low hydration (Bellow about 33% RH) the spectrum was characteristic of carboxy derivative, whereas at high hydration (above about 93% RH) the spectrum was characteristic of oxy derivative, and in the the intermediate region the spectrum was a mixture of both derivatives. This ligand change observed at high hydration, may be explained assuming that the protein has flexibility, and reach a conformational state which enables the ligand to GO in and out. At low hydrations the protein structure is rigid and such that the access to the heme group is closed becoming impossible the ligand change. This explanation agrees with several experimental results that point to the existence of two structures to these hemoproteins in solution

Introdução: Apesar da falta de evidência cientifica, costuma-se pensar que crianças obesas apresentam desvantagens e são menos tolerantes ao se exercitarem no calor. Objetivo: Comparar a sudorese, balanço hidro-eletrolítico e a tolerância ao exercício no calor entre meninos pré-púberes obesos e eutróficos que pedalam no calor. Métodos: Trinta meninos pré-púberes foram alocados para o grupo de obesos (GO, n=15) e eutróficos (GE, n=15). Após uma sessão de avaliação, os meninos vieram ao laboratório para a sessão de exercício no calor (35C, 40-45%UR). Eles pedalavam por 30 minutos a 50-60% do seu VO2pico pré determinado. Para coletar o suor, adesivos foram fixados sobre 4 regiões da pele (costas, peito, antebraço e coxa) e as amostras foram analisadas para eletrólitos (AVL, 9180). Após o exercício, amostras de urina foram coletadas para análise de volume e eletrólitos para coleta regional de suor (AVL, 9180). Após a pedalada, os meninos descansaram por 10 min e pedalaram a 90% do VO2pico até a exaustão e o tempo de desempenho foi registrado. Durante a sessão, a ingestão “ad libitum” de uma bebida esportiva foi avaliada. Sensação subjetiva de calor foi avaliada durante toda a sessão. Resultados: A taxa de sudorese relativa a área de superfície corporal foi similar entre eutróficos e obesos (488  232 e 417  89.6 ml.m2.min-1, respectively; p=0,004) e as [Na+] e [Cl-] no suor foram maiores nos meninos obesos (p=0,005), enquanto a [K+] foi similar entre os grupos (p = 0,004). Ambos os grupos apresentaram um balanço hidroeletrolítico negativo, mas não existiu diferença entre os grupos. O tempo de desempenho foi maior no GE (89.6  64.1) que o GO (41.2  29.6 seg; p=0,005). A sensação subjetiva de calor foi maior no GO que no GE em todos os momentos (p = 0,005). Conclusão: Meninos pré-púberes obesos apresentaram uma similar taxa de sudorese relativa à área de superfície corporal, menor tolerância ao exercício no calor, e maior [Na+] e [Cl-] no suor comparado aos eutróficos. Crianças obesas não diferem das eutróficas em relação ao balanço hidroeletrolítico. / Introduction: Despite the lack of scientific evidence, it is generally thought that obese children have disadvantages and are less tolerant to exercise in the heat when compared to lean children. Purpose: To compare sweating, water and electrolyte balance, and exercise tolerance heat between obese and lean boys who cycled in the heat. Methods: Thirty prepubertal boys formed an obese (OG, n=15) and a lean (LG, n=15) group. After a screening session and evaluation of physical characteristics and VO2peak, the boys came to the laboratory for the exercise session in the heat (35C, 40-45%RU). They cycled for 30 minutes at 50-60% of their pre-determined VO2peak. To collect sweat, patches were attached on 4 regions of the skin (back, chest, forearm and thigh) and samples were analyzed for electrolytes (AVL 9180). After exercise, urine samples were collected for volume and electrolyte analyses (AVL 9180). After this cycling, the boys rested 10 min and cycled at 90% VO2peak until exhaustion and the performance time was registered. During the whole session, a sports drink was available to drink “ad libitum” and the intake was registered. Heat subject sensation (HSS) was evaluated during the whole session. Results: Sweat rate relative to body surface area was similar between lean and obesity boys (488  232 and 417  89.6 ml.m2.min-1, respectively; p=0.004) and sweat [Na+] and [Cl-] were higher in the obese boys (p=0.005), whereas [K+] was similar between groups (p = 0.004). Both groups showed a negative water and electrolyte balance, but there was no difference between groups. The performance time was longer in the LG (89.6  64.1) than OG (41.2  29.6 sec; p=0.005). The heat subjective sensation was higher in GO than in GE at all times (p = 0.005). Conclusion: Obese prepubescent boys showed similar sweat rate relative to body surface area, lower exercise heat tolerance, and increased [Na+] and [Cl-] sweat loss compared to lean children. Obese children did not differ from lean children related to water and electrolyte balance.

Dans les structures confinées, comme les silices mésoporeuses, la mobilité et l'interaction des cations avec les surfaces sont des phénomènes clés. Ils guident les propriétés d'adsorption dont découlent de nombreuses applications, en particulier pour l’extraction et la séparation. Ce travail de thèse en modélisation propose de s'intéresser aux propriétés d'interface, d'équilibre et de transport qui pilotent l'échange ou l'adsorption ionique. Il s’agit de décrire la physico-chimie du processus d’adsorption de cations alcalins à la surface de silices chargée par une approche multiéchelle ayant une base moléculaire. Pour cela une étude de la série des alcalins (Li+, Na+, K+ et Cs+) a été menée. Le cadre théorique est la théorie de Mc Millan Mayer. Celle-ci, fondamentale pour les solutions libres s’est révélée également être une méthode de choix pour les milieux confinés. Le potentiel de force moyenne de McMillan Mayer entre les ions et des sites de surface a pu être calculé par la méthode d'Umbrella Sampling associé à l’algorithme WHAM. Le phénomène qui s’est révélé le plus pertinent correspond à la présence de paires au contact (Contact Ion Pairs - CIP) entre les oxygènes de la surface et les cations, sans molécule d’eau qui les sépare. Ces CIP se traduisent dans les courbes de potentiel par un premier minimum d’intensité supérieure à l’agitation thermique. Pour les petits ions (lithium), ce complexe de surface est particulièrement stable, les constantes d’adsorption et les temps de résidence étant particulièrement élevés, ce qui rend délicat la simulation moléculaire directe de ces phénomènes. Il a été observé une inversion de sélectivité entre les sites silanolates et siloxanes. L'adsorption est différente pour un ion cosmotrope comme Li+ qui doit se déshydrater pour s'adsorber et un ion chaotrope comme Cs+ qui est moins lié au solvant. Les constantes d’adsorption de chaque site de même type ne sont pas toutes égales. L’étude des phénomènes électrocinétiques (électro-osmose et conductivité de surface) a également été menée en comparant les descriptions classiques (modèles de Poisson-Boltzmann, de Smoluchowski, et de Bikerman) aux résultats de dynamique moléculaire. Il est apparu que l'image traditionnelle en plusieurs couches des interfaces (couches de Helmholtz internes et externes, de Stern, de Gouy-Chapman, plan de cisaillement) devait être remplacée par un modèle beaucoup plus simple mais plus efficace. Du point de vue des ions, deux domaines apparaissent : les CIP, globalement fixés à la surface transmettant la force électrique au solide et pas au fluide, et les autres ions, globalement libres, transmettant la force électrique au fluide. Aucune viscosité ou constante diélectrique dépendant de la distance n’a été mise en évidence. Une diminution de la mobilité des ions à proximité de la surface a en revanche été observée. Ce phénomène peut être quantitativement compris comme un effet hydrodynamique du à la présence des surfaces qui gênent le flux en retour du solvant. Ce travail permet ainsi de mieux caractériser l'interface verre chargé-solution pour les applications en science de la séparation. Il a pu montrer comment les simulations moléculaires pouvaient non seulement prédire les paramètres des modèles macroscopiques (constantes d’adsorption, coefficients de transport, etc.) mais surtout modifier ceux-ci pour les rendre en accord avec la description moléculaire. Une telle stratégie pourra par la suite être mise en œuvre sur des systèmes plus complexes, comme des modèles de surfaces greffées. / In confined structures, such as mesoporous silica, the mobility of the cations and the surface/cations interactions are key phenomena. They drive adsorption properties, which control numerous applications, especially for extraction and separation. This modelling work describes equilibrium and transport interface properties that control ion exchange and ionic adsorption. The physical and chemical properties of adsorption processes of alkali cations at the surface of charged silica is studied thanks to a multiscale approach based on a molecular description. The systematic study of alkali serie (Li+, Na+, K+ and Cs+) has been studied to that goal. The theoretical framework is Mc Millan-Mayer theory. The latter, which is known to be of fundamental significance for bulk solutions is found to be also relevant for confined media. The mean force potential of Mc Millan-Mayer between ions and surface sites has been calculated by Umbrella Sampling associated to the WHAM algorithm. The most important phenomenon we identified corresponds to the existence of Contact Ion Pairs (CIP) between the surface oxygen and the cations, without separating solvent molecules. The CIP correspond to the first minima in the potential curves if the associated energy is more than the thermal agitation (kT). For small ions (lithium) this surface complex is especially stable, adsorption constant and residence time being particularly high so that the direct molecular simulations are very difficult. A selectivity inversion has been observed between silanolates and siloxanes. Adsorption is different for kosmotropic ions (as Li+) which has to be dehydrated to be adsorbed and chaotropic ions (as Cs+) for which the solvent bound is weaker. Adsorption constants for sites of the same nature are not equal. The study of the electrokinetic phenomena (electro-osmosis and surface conductivity) has also been performed by comparing the classical descriptions (Poisson-Boltzmann, Smoluchowski, and Bikerman models) to molecular simulations. The traditional picture of the interface with several layers (inner and outer Helmholtz, Stern and Gouy-Chapman layers, shear plane) is found to be replaced by a simpler but more efficient model. For the ions, two domains are obtained: (i) CIPs, firmly bound to the surface that transmit the electrical force to the solid (and not the fluid) (ii) other ions that are globally free that transmit the electric force to the fluid. No space dependent viscosity or dielectric constant have been obtained. On the other hand, a decrease of ion mobility in the vicinity of the surface has been observed. This phenomenon can be quantitatively understood as a hydrodynamic effect that comes from the solid surface, which hinders the backflow of the solvent. This work allows a better characterization of charged glass-solution interfaces for separation science. It shows how molecular simulations can not only predict the parameters of macroscopic models (adsorption constant, transport coefficients), but also modify the latters in order to make them in agreement with molecular descriptions. Such a strategy can be extended to more complex systems, such as models of grafted surfaces.

Introdução: a água é componente vital para o desempenho das funções corporais e fundamental para a produção vocal. Sabe-se ainda que exercícios de aquecimento vocal preparam a voz para o canto. O propósito deste estudo foi investigar a influência da hidratação sistêmica na voz de coristas sem e com aquecimento vocal. Material e métodos: esta pesquisa teve a aprovação do CEP-FOB/USP, protocolo: 085/2011. Participaram 16 coristas, com média de idade de 49,38 anos, DP 14,74, sendo 12 do sexo feminino (75%) e quatro do sexo masculino (25%). Todos os coristas eram integrantes de coros há no mínimo um ano, saudáveis, sem queixas vocais e auditivas nos dias das avaliações e sem histórico de cirurgias laríngeas. Procedimentos: os participantes tiveram suas vozes avaliadas em dois dias não consecutivos, o primeiro na condição desidratado (D) e o segundo na condição hidratado (H). Em ambos os dias tiveram suas vozes gravadas antes (D1 e H1) e após a realização do aquecimento vocal (D2 e H2). Para a condição desidratado os coristas ficaram sem ingerir água durante as 12 horas que antecederam a primeira avaliação. Para a condição de hidratado houve a ingestão fracionada de três litros de água para os homens e dois litros para as mulheres no dia anterior ao dia da segunda avaliação. As condições hidratado e desidratado foram avaliadas por meio da coloração e gravidade específica da urina. Foi realizada a avaliação acústica dos parâmetros F0, jitter, shimmer e NHR, por meio do Multi Dimensional Voice Program (MDVP). A análise perceptivo-auditiva considerou o grau geral, a rugosidade, a soprosidade, a tensão, o pitch e o loudness da vogal /a/ sustentada por meio da escala visual analógica (EVA). As vozes foram analisadas pela fonoaudióloga que apresentou melhor análise intra-juiz (p=0,000 e r=0,77). Resultados: houve forte correlação entre os métodos da coloração e a gravidade específica da urina (r=0,807 e p<0,05). Na avaliação acústica houve redução da F0 e melhora do shimmer e na avaliação perceptivo-auditiva foi identificada melhora dos parâmetros da rugosidade, soprosidade, tensão e redução do pitch, nas vozes hidratadas sem aquecimento vocal. Nas vozes com aquecimento vocal a avaliação acústica revelou estabilidade da F0 e melhora do shimmer e na perceptivo-auditiva redução da rugosidade e do pitch. Conclusão: a hidratação sistêmica agiu positivamente na voz sem aquecimento vocal revelando na avaliação acústica redução da F0 e melhora do shimmer e na avaliação perceptivo-auditiva melhora dos parâmetros da rugosidade, soprosidade, tensão e redução do pitch. A hidratação sistêmica agiu positivamente na voz com aquecimento vocal revelando na avaliação acústica estabilidade da F0 e melhora do shimmer e na perceptivo-auditiva redução da rugosidade e do pitch. / Introduction: Water is a vital component for bodily functions and is fundamental for voice production. It is known that vocal warming exercises prepare the voice for singing. The purpose of this study was to investigate the influence of systemic hydration on choristers voices whilst warmed and unwarmed. Material and Methods: This research had the approval from CEP-FOB/USP protocol 085 2011. 16 choristers took part on the research, whose average age is 49.38 years (standard deviation 14,74), being 12 female (75%) and 4 male (25%). All choristers are healthy, do not present complaint on vocal or hearing issues during test days and do not possess history of laryngeal surgery. Procedure: the participants had their voices evaluated in two non-consecutive days, with hydrated voice (H) on the first day and with dehydrated voice (D) on the second. In both days, their voices were recorded before vocal warming (D1 and H1) and after vocal warming (D2 and H2.) For the dehydration condition, the choristers drank no water during the 12 preceding hours relative to the first test. For the hydration condition, fractioned water intake(3 liters for men and 2 liters for women) was held on the day before the second test. Hydrated and dehydrated conditions were determined by means of urine coloration and specific gravity. The acoustic evaluation was performed focusing in parameters F0, jitter, shimmer and NHR using the multidimensional voice program. The perceptual-auditory analysis considered the overall degree, rugosity, breathiness, tension, pitch and loudness of the sustained vowel a by visual analog scale. The voices were analyzed by the speech therapist who presented best intra-judge analysis (P = 0.000, R = 0.77). Results: The urine coloration and specific gravity have held strong correlation, with R = 0.807 and P < 0.05. On the acoustic evaluation, there has been reduction of F0 and shimmer improvement; and in the perceptive-auditory evaluation it was identified improvement on rugosity, breathiness, tension and reduction of pitch on hydrated unwarmed voices. On warmed voices, the acoustic evaluation revealed stability on F0 and improvement on shimmer; on the perceptive-auditory evaluation, rugosity and pitch have reduced. Conclusion: The systemic hydration acted positively on unwarmed voice revealing F0 reduction and shimmer improvement on the acoustic evaluation; and improvement on rugosity, breathiness, tension and pitch on the perceptive-auditory evaluation. Also, systemic hydration acted positively on the warmed voice, revealing F0 stability and shimmer improvement on the acoustic evaluation; and rugosity and pitch reduction on the perceptive-auditory evaluation.