High-tone extensor thrusts, or involuntary muscle contractions experienced by many children with cerebral palsy, can cause problems that are not addressed by current seating systems. This thesis is concerned with the development of a dynamic seating system to better accommodate individuals who exhibit high-tone extensor thrusts. The first part of the thesis is focused on obtaining a general understanding of extensor thrusts from a mechanical perspective. To achieve this goal, an analytical dynamic model of a human subject undergoing an extensor thrust on a rigid chair is created. This model is validated experimentally, and inferences about the nature of extensor thrusts are made from the simulation and experimental results. A Dynamic-Hingeback Seating System which allows the occupant to lean back during an uncontrolled extensor thrust is developed. This system is capable of maintaining seatback rigidity during an intentionally-induced episode, thereby enabling the occupant to communicate or interact with his/her environment. The design of this system is influenced by the results obtained from the rigid seat study, as well as by numerical simulation results gathered with a commercial dynamic simulation software package (Working Model 2D). The improved seatback performance is characterized through experimentation. Alternative dynamic seating systems are considered. The important features of each of these systems are identified, and the desired motion of the system occupant during an extensor thrust is verified through Working Model simulations.

The knee joint plays an essential role in the human musculoskeletal system. It has evolved to withstand extreme loading conditions, while providing almost frictionless joint movement. However, its performance may be disrupted by disease, anatomical deformities, soft tissue imbalance or injury. Knee disorders are often puzzling, and accurate diagnosis may be challenging. Current evaluation approach is usually limited to a detailed interview with the patient, careful physical examination and radiographic imaging. The X-ray screening may reveal bone degeneration, but does not carry sufficient information of the soft tissue conditions. More advanced imaging tools such as MRI or CT are available, but expensive, time consuming and can be used only under static conditions. Moreover, due to limited resolution the radiographic techniques cannot reveal early stage arthritis. The arthroscopy is often the only reliable option, however due to its semi-invasive nature, it cannot be considered as a practical diagnostic tool. Therefore, the motivation for this work was to combine three scientific methods to provide a comprehensive, non-invasive evaluation tool bringing insight into the in vivo, dynamic conditions of the knee joint and articular cartilage degeneration. Electromyography and inverse dynamics were employed to independently determine the forces present in several muscles spanning the knee joint. Though both methods have certain limitations, the current work demonstrates how the use of these two methods concurrently enhances the biomechanical analysis of the knee joint conditions, especially the performance of the extensor mechanism. The kinetic analysis was performed for 12 TKA, 4 healthy individuals in advanced age and 4 young subjects. Several differences in the knee biomechanics were found between the three groups, identifying age-related and post-operative decrease in the extensor mechanism efficiency, explaining the increased effort of performing everyday activities experienced by the elderly and TKA subjects. The concept of using accelerometers to assess the cartilage degeneration has been proven based on a group of 23 subjects with non-symptomatic knees and 52 patients suffering from knee arthritis. Very high success (96.2%) of pattern classification obtained in this work clearly demonstrates that vibroarthrography is a promising, non-invasive and low-cost technique offering screening capabilities.

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.

This study investigated the effect of chain extender epoxy based additive, Joncryl ADR 4368, on the rheological, thermal and mechanical properties of poly(lactic acid) with poly(butylene adipate-co-terephthalate) (PLA/PBAT) blends in the blown films form. Compositions with 40% and 60% by weight PLA were selected for production of such blown films. These dispersed phase content was chosen because the literature does not present mechanical behavior studies of tubular film blends with high concentration of the dispersed phase. Rheological analysis in dynamic oscillatory regime showed the reaction of epoxy group with end chain in both polymers, and a higher reactivity of the chain extender with PLA. The films produced exhibited different morphologies according to the blend composition and chain extender content. Films containing 40% PLA presented the dispersed phase morphology in a fibrillar form; however in the presence of chain extender, the dispersed phase is presented as ellipsoids. This change in morphology resulted in a reduction in the mechanical properties of these films in tensile tests. Films containing 60% PLA had a coarse morphology with dispersed phase in the ribbons-like form. The addition of extender yielded a refinement of the dispersed phase morphology from ribbon to elongated fibril form, which is responsible for the mechanical properties improvement of these films. Despite the low adhesion between matrix and dispersed phase, the proper setting of the morphology of the blends as a function of additive content, allowed to produce films with mechanical properties quite different from each other. / Neste trabalho foi estudado o efeito do aditivo extensor de cadeia à base de epóxi, Joncryl ADR 4368, nas propriedades reológicas, térmicas e mecânicas de filmes tubulares de blendas de poli(ácido láctico) com poli(butileno adipato-co-tereftalato) (PLA/PBAT). Composições com 40% e 60% em peso de PLA foram selecionadas para produção destes filmes tubulares. Estes teores de fase dispersa foram escolhidos pelo fato da literatura não apresentar estudos de comportamento mecânico de filmes tubulares de blendas com alta concentração da fase dispersa. Análises reológicas em regime dinâmico oscilatório evidenciaram a reação do grupo epóxi com finais de cadeia de ambos os polímeros, e evidenciaram uma maior reatividade do extensor com o PLA. Os filmes produzidos apresentaram diferentes morfologias de acordo com a composição da blenda e o teor de extensor de cadeia adicionado. Filmes contendo 40% de PLA apresentaram uma morfologia da fase dispersa na forma fibrilar; já na presença do extensor, a fase dispersa se apresentou na forma de elipsóides. Esta mudança na morfologia acarretou em uma redução nas propriedades mecânicas destes filmes em ensaios de tração. Filmes contendo 60% de PLA apresentaram uma morfologia grosseira com a fase dispersa na forma de fitas. A adição do extensor proporcionou um refinamento na morfologia da fase dispersa com formação de fibrilas alongadas, responsável pelo ganho nas propriedades mecânicas destes filmes. Apesar da baixa adesão entre matriz e fase dispersa, o ajuste apropriado da morfologia das blendas, em função do teor de aditivo, possibilitou produzir filmes com propriedades mecânicas bastante diferenciadas entre si.

Introduction: Maximum running acceleration essential components in many sports. The identification of specific training protocols to maximize sprint speed would be useful knowledge for soccer coaches and players. Purpose: The purpose of this study was to determine the effect of a high-speed treadmill with the use of a body-weight support system in a 6-week sport acceleration program on: 40-yard sprint time, maximal isometric knee flexor and extensor strength. Methods: 32 female soccer players (age 16 ± 1.19 yrs) participated in two treatment groups and one control group. Both treatment groups participated in a 12-session sport acceleration program. The first treatment group utilized a body-weight support system while on a high-speed treadmill; the second group used a standard treadmill with no body weight support system. The control group, NT, did not participate in a sports acceleration program and did not alter their exercise routines outside of the study. Results: For each variable an Analysis of Covariance (ANCOVA) was performed. 40-yard sprint times for treatment groups were shown to improve significantly as compared to the control group (p = 0.0007 for high-speed treadmill with body-weight support system, p= < 0.0001 for standard treadmill without body-weight support system). Isometric flexor and extensor strengths did not show significant differences between treatment groups and control group. P-values for the high-speed with body-weight support system were (p = 0.53) for flexors and (p = 0.51) for extensors as compared to the control group. P-values for the standard treadmill with no body-weight support system were (p = 0.19) for extensors and (p = 0.0263) for flexors. It is noted that the extensor muscles were nearly significant for the standard treadmill with no body-weight support system. Discussion: These results can help high school coaches and athletes determine the optimal treadmill training regime. The current study shows that a high-speed treadmill with body-weight support system is just as beneficial as standard treadmill training.

L’objectif de ce travail était de déterminer i) l’influence du niveau de force absolue sur la durée du temps de maintien, et les altérations neuromusculaires subséquentes chez un même individu à l’issue d’un exercice réalisé à la même intensité relative, avec un ou deux membres ; ii) l’influence de la commande nerveuse sur la capacité de production de force de chacun des muscles extenseurs du genou lors de contractions unilatérales (UL) vs. bilatérales (BL); iii) l’évolution des mécanismes d’activation pendant une série de contractions sous-maximales évoquées par électromyostimulation (EMS).Les résultats de la première étude confirment que le temps limite est dépendant du niveau de force absolu pour un même individu, la durée de la contraction en UL étant 20% plus longue qu’en BL. De plus, une corrélation a été trouvée entre la force lors d’une contraction maximale volontaire (CMV) et le temps limite en UL et BL. Toutefois, d’autres mécanismes semblent être également mis en jeu, car dans un cas les mécanismes sont d’origine nerveux et musculaire (UL), alors que dans l’autre cas les mécanismes sont seulement nerveux (BL). Les résultats de la deuxième étude montrent que la force maximale développée lors d’une contraction BL est inférieure à la somme des forces des contractions UL (i.e. présence d’un déficit bilatéral). Les temps d’apparition des pics de force lors des CMV de chacune des jambes ne sont pas différents de celui de la CMV BL, mais la force développée au cours de celle-ci est inférieure à la somme des CMV de chacune des jambes durant la CMV BL, c'est-à-dire à la force maximale produite par chacune des jambes lors de la CMV BL. Néanmoins, aucune différence d’activité EMG, d’amplitude d’onde M, de doublet et de niveau d’activation n’a été observée entre les conditions UL et BL. Les résultats de la troisième étude montrent que l’estimation de la commande descendante, par la technique de la secousse surimposée, lors d’un effort sous-maximal fatigant présente des biais méthodologiques. Toutefois, l’estimation des mécanismes nerveux par les deux méthodes classiques (niveau d’activation volontaire (NAV) et ratio d’activation centrale (CAR)) reste néanmoins pertinente pendant des contractions maximales volontaires. L’ensemble de nos travaux met en évidence l’intervention de mécanismes d’origine nerveux différents entre les contractions UL et BL / The aim of this work was to determine i) the influence of the level of absolute force on the duration of the endurance time, and subsequent neuromuscular alterations in same individual at the end of an exercise performed at the same relative intensity, with one or two legs, ii) the influence of central drive on the force capacity production of the knee extensor muscles during unilateral (UL) vs. bilateral (BL) contractions, iii) activation mechanisms evolution for a serie of submaximal evoked contractions by electrostimulation (EMS). The results of the first study confirm that the endurance limit depends on the level of absolute force for the same individual, contraction duration for UL is 20% longer than for BL. In addition, a correlation was found between the maximal voluntary contraction force (MVC) and the endurance time in UL and BL. However, other mechanisms also appear to be involved, because in one case the mechanisms are nervous and muscular (UL), while in other cases the mechanisms are only nervous (BL). The results of the second study show that maximal force developed during BL contraction is less than the sum of the forces of UL contraction (i.e. a bilateral deficit). The timing of MVC peak force production during each leg of MVC are not different from that of BL MVC, but the force developed during the latter is less than the sum of MVC in both legs during the BL MVC, i.e. the maximum force produced by each leg during BL MVC. However, no difference in EMG activity, M-wave amplitude, doublet and level of activation was observed between UL and BL conditions. The results of the third study show that the estimation of the central drive, by the technique of superimposed twitch during a submaximal fatiguing effort presents methodological bias. However, estimation of neural mechanisms with both conventional methods (voluntary level activation (VAL) and central activation ratio (CAR)) remains relevant during maximal voluntary contractions. This work évidences the presence of different nervous mechanisms between UL and BL contractions

[ES] A la luz de la crisis medioambiental y del creciente interés en el uso del H2 para avanzar hacia la Economía del Hidrógeno, esta tesis tiene como objetivo analizar y optimizar nuevas arquitecturas de sistemas propulsivos de FCV para aplicaciones en turismos y vehículos pesados en términos de rendimiento, durabilidad e impacto medioambiental. Para ello, se ha desarrollado una plataforma de modelado de FCV multifísica y flexible que integra un modelo de pila de combustible validado junto con los componentes del BoP, los componentes mecánicos y eléctricos del vehículo y el sistema propulsivo, un modelo de degradación de FC semi-empírico informado por tendencias físicas diseñado para ser utilizado en condiciones de conducción y un optimizador de EMS en tiempo real que ofrece el mejor rendimiento dado un diseño de sistema propulsivo y un ciclo de conducción, de tal forma que todas las arquitecturas propuestas para una aplicación determinada sean comparables en términos justos. La discusión de los resultados puede dividirse en tres partes diferentes. La primera está orientada a la optimización del rendimiento del FCS. Los resultados de esta parte ayudaron a identificar la estrategia de gestión del aire que, dado un conjunto de restricciones impuestas en los componentes del BoP, maximizaba la potencia neta del FCS (eficiencia) para cada valor de densidad de corriente. El balance energético resultante, que comprende la potencia producida por la pila de combustible, las perdidas electroquímicas y el consumo de los componentes del BoP, fue analizado y utilizado para determinar y diseñar la estrategia de control de los actuadores del BoP para condiciones de conducción. La segunda parte se centra en la evaluación y optimización, cuando es posible, de la arquitectura FCREx para aplicaciones de turismos y la configuración multi-FCS para aplicaciones de vehículos de transporte pesado. Desde el punto de vista del rendimiento, la arquitectura FCREx ofrecía un consumo mínimo de H2 con una elevada potencia de la pila de combustible y una gran capacidad de la batería, pero este diseño podría ser prohibitivo en términos de costes. Podía ofrecer hasta un 16.8-25% menos de consumo de H2 y un 6.8% menos de consumo de energía. La limitación en la dinámica de esta arquitectura aumento la durabilidad de la FC en un 110% con una penalización en el consumo de H2 del 4.7%. La arquitectura multi-FCS para aplicaciones pesadas podría funcionar con una dinámica aún menor, con un aumento de la durabilidad de la pila del 471% con una penalización en el consumo de H2 del 3.8%, ya que el perfil de conducción de los vehículos pesados suele ser menos dinámico. El control y el dimensionamiento diferencial solo podrían aportar beneficios en términos de impacto ambiental o de coste, pero no de rendimiento. La última parte considera los resultados obtenidos en términos de rendimiento y durabilidad para analizar el impacto medioambiental de cada arquitectura. La estrategia de producción de H2 afecta significativamente a las emisiones del ciclo de vida en ambas aplicaciones sobre cualquier otra elección de diseño. El diseño óptimo para la arquitectura FCREx que minimiza las emisiones tiene una alta potencia de la pila de combustible y una capacidad moderada de la batería. En el caso de la aplicación para vehículos pesados, se identificó la dinámica de control óptima para cada diseño y estrategia de producción de H2, y se determinó que la estrategia de diseño de dimensionado diferencial solo proporcionaba beneficios si se consideraba una tecnología de pila de combustible diferente para las distintas pilas integradas en el sistema propulsivo. / [CA] A la llum de la crisi mediambiental i del creixent interés en l'ús de l'H2 per a avançar cap a l'Economia de l'Hidrogen, aquesta tesi té com a objectiu analitzar i optimitzar noves arquitectures de sistemes propulsius de FCV per a aplicacions en turismes i vehicles pesants en termes de rendiment, durabilitat i impacte mediambiental. Per a això, s'ha desenvolupat una plataforma de modelatge de FCV multifísica i flexible que integra un model de pila de combustible validat juntament amb els components del BoP, els components mecànics i elèctrics del vehicle i el sistema propulsiu, un model de degradació de pila de combustible semi-empíric informat per tendències físiques dissenyat per a ser utilitzat en condicions de conducció i un optimitzador d'EMS en temps real que ofereix el millor rendiment donat un disseny de sistema propulsiu i un cicle de conducció, de tal forma que totes les arquitectures proposades per a una aplicació determinada siguen comparables en termes justos. La discussió dels resultats pot dividir-se en tres parts diferents. La primera està orientada a l'optimització del rendiment del FCS. Els resultats d'aquesta part van ajudar a identificar l'estratègia de gestió de l'aire que, donat un conjunt de restriccions imposades en els components del BoP, maximitzava la potència neta del FCS (eficiència) per a cada valor de densitat de corrent. El balanç energètic resultant, que comprén la potència produïda per la pila de combustible, les pèrdues electroquímiques i el consum dels components del BoP, va ser analitzat i utilitzat per a determinar i dissenyar l'estratègia de control dels actuadors del BoP per a condicions de conducció. La segona part se centra en l'avaluació i optimització, quan ¿es possible, de l'arquitectura FCREx per a aplicacions de turismes i la configuració multi-FCS per a aplicacions de vehicles de transport pesat. Des del punt de vista del rendiment, l'arquitectura FCREx oferia un consum mínim d'H2 amb una elevada potència de la pila de combustible i una gran capacitat de la bateria, però aquest disseny podría ser prohibitiu en termes de costos. Podia oferir fins a un 16.8-25% menys de consum d'H2 i un 6.8% menys de consum d'energia. La limitació en la dinàmica d'aquesta arquitectura va augmentar la durabilitat de la pila en un 110% amb una penalització en el consum d'H2 del 4.7%. L'arquitectura multi-FCS per a aplicacions pesades podria funcionar amb una dinàmica encara menor, amb un augment de la durabilitat de la pila del 471% i una penalització en el consum d'H2 del 3.8%, ja que el perfil de conducció dels vehicles pesants sol ser menys dinàmic. El control i el dimensionament diferencial només podrien aportar beneficis en termes d'impacte ambiental o de cost, però no de rendiment. L'última part considera els resultats obtinguts en termes de rendiment i durabilitat per a analitzar l'impacte mediambiental de cada arquitectura. L'estratègia de producció d'H2 afecta significativament a les emissions del cicle de vida en totes dues aplicacions sobre qualsevol altra elecció de disseny. El disseny òptim per a l'arquitectura FCREx que minimitza les emissions té una alta potència de la pila de combustible i una capacitat moderada de la bateria. En el cas de l'aplicació per a vehicles pesants, es va identificar la dinàmica de control `optima per a cada disseny i estratègia de producció d'H2, i es va determinar que l'estratègia de disseny de dimensionament diferencial només proporcionava beneficis si es considerava una tecnologia de pila de combustible diferent per a les diferents piles integrades en el sistema propulsiu. / [EN] In light of the environmental crisis and the growing interest in the use of H2 to advance toward the Hydrogen Economy, this thesis aims at analyzing and optimizing novel FCV powerplant architectures for passenger car and heavy-duty vehicle applications in terms of performance, durability, and environmental impact. For that purpose, a multi-physics flexible FCV modeling platform was developed integrating a validated FC stack model together with the BoP components, the mechanical and electrical components of the vehicle and powertrain, a semi-empirical physics-informed FC degradation model designed to be used in driving conditions and a real-time EMS optimizer that offers the best performance given a powerplant design and driving cycle so that all the proposed architectures for a given application are comparable. The discussion of the results can be divided into 3 different parts. The first one is oriented towards the FCS performance optimization. The results in this part helped to identify the air management strategy that, given a set of constraints imposed in the BoP components, maximized the FCS net power output (efficiency) for each value of current density. The resulting energy balance comprising the FC stack power produced, the electrochemical losses, and the consumption of the BoP components was analyzed and used to determine and design the control strategy of the BoP actuators for driving cycle conditions. The second part is focused on the evaluation and optimization, when possible, of the FCREx architecture for passenger car applications and the multi-FCS configuration for heavy-duty vehicle applications. Performance-wise the FCREx architecture offered minimum H2 consumption with high FC stack power and high battery capacity, but this design could be prohibitive in terms of costs. It could offer up to 16.8-25% lower H2 consumption and 6.8% lower energy consumption. Limiting the dynamics of this architecture increased the FC durability by 110% with a penalty in H2 consumption of 4.7%. The multi-FCS architecture for heavy-duty applications could operate with even lower dynamics, with an increase in the FC durability of 471% with a penalty in H2 consumption of 3.8%, since the driving profile of heavy-duty vehicles is usually more steady. Differential control and sizing could only provide benefits in terms of environmental impact or cost, not performance. The last part considers the results obtained in terms of performance and durability to analyze the environmental impact of each architecture. The H2 production pathway affected significantly the life cycle emissions of both applications over any other design choice. The optimum design for FCREx architecture that minimized emissions had high FC stack power and moderate battery capacity. In the case of heavy-duty application, the optimum control dynamics for each design and H2 production pathway were identified, and the differential sizing design strategy was determined to only provide benefits if different FC stack technology was considered for the various stacks in the powerplant. / López Juárez, M. (2022). Analysis of Hydrogen Fuel Cell Powerplant Architectures for Future Transport Applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/189212

Previous studies that utilized sodium lactate infusion did not use resistance exercise protocol or analyzed muscle biopsies, or performed sex specific analysis. Aim: We initiated a project where resistance exercise was performed with low and high levels of lactate, acquired by venous lactate infusion where the specific aim of this study was to investigate and chart the physiological characteristics of sodium lactate infusion during a bout of resistance exercise on whole group level and sexes separated Method: A randomized, placebo controlled, cross-over design was implemented where male (n = 8) and female (n = 8) subjects accustomed to resistance exercise visited the laboratory three times for preliminary testing and training familiarization. In the following two experimental trials subjects arrived in an overnight fasted state. A resting state muscle biopsy was extracted from m. vastus lateralis and repeated blood samples were initiated which followed by 20 minute of baseline infusion of either infusate in resting state at 0.05 mmol/kg/min infusion rate with additional bolus doses during subsequent exercise. Following a brief warm up, unilateral knee-extensions (6 x 8-10 reps at 75% of 1-RM) were performered with or without venous infusion of sodium lactate, with volume matched saline as control. Exercise load and volume were matched between trials. Four additional biopsies were extracted at post-exercise, recovery period, and 24-hour post-exercise. Results: Sodium lactate infusion vs saline infusion respectively during resistance exercise yielded significantly higher blood lactate with sodium lactate (6.78 ± 0.33 mmol/l vs 2.99 ± 0.17 mmol/l), plasma lactate (8.86 ± 0.39 mmol/l vs 4.39 ± 0.22 mmol/l), blood sodium (143 ± 0.4 mmol/l vs 142 ± 0.3 mmol/l), blood pH (7.42 ± 0.01 vs 7.34 ± 0.01), but lower blood potassium (3.9 ± 0.1 mmol/l vs 4.2 ±  0.1 mmol/l), all  immediately following exercise. Sodium lactate infusion elicited main effect of trials and muscle lactate increased from baseline (8.5 ± 0.9 mmol·kg-1 dw vs 7.0 ± 0.6 mmol·kg-1 dw) to post-exercise (31.5 ± 2.8 mmol·kg-1 dw vs 26.9 ± 3.2 mmol·kg-1 dw) with sodium lactate and saline infusion respectively. Blood glucose, hemoglobin and muscle pH was not affected by sodium lactate infusion. Conclusions: Utilization of the sodium lactate infusion method during a bout of resistance exercise may be used as tool to effectively increase blood/plasma lactate and, to lesser extent, muscle content of lactate. However, a concomitant slightly alkalizing effect of blood likely will occur. / Tidigare studier som använt natriumlaktat infusion använde inte styrketräningsprotokoll, eller analyserade muskelbiopsier eller utförde könsspecifika analyser. Syfte och frågeställningar: Vi initierade ett projekt där styrketräning utfördes med låga eller höga nivåer av laktat som erhölls genom venös natriumlaktat infusion med det specifika syftet att undersöka och kartlägga fysiologisk karakteristiska av naturiumlaktat infusion under styrketräningsövning på helgrupps- och könsseparerad nivå. Följande frågeställningar inrättades; hur påverkar natriumlaktat infusion under styrketräning helblod- och plasma laktat, glukos, natrium, kalium, plasma volym genom hemoglobin och hematokrit, blod pH, muskellaktat- och muskel pH samt om skillnader i respons finns efter att könsspecifika analyser utförts på dessa variabler. Metod: En randomiserad, placebokontrollerad cross-over design implementerades där styrketräningsvana män (n = 8) och kvinnor (n = 8) besökte laboratoriet tre gånger för preliminäraför tester och träningsfamiliarisering. I efterföljande två experimentella försök anlände försökspersonerna i ett över nattligt fastande tillstånd. En baslinje biopsi extraherades från m. vastus lateralis och repeterade blodprover initierades med efterföljande 20 minuter av baslinje infusion av endera infusat i vilotillstånd med 0.05 mmol/kg/min infusionshastighet med ytterligare bolusdoser under efterföljande träning. Efter en kort uppvärmning utfördes unilaterala knäextensioner (6 x 8-10 reps vid 75% av 1-RM) med eller utan venös infusion av natrium laktat, med volymmatchande saltlösning som kontroll. Träningsbelastning och volym matchades mellan försök. Ytterligare fyra biopsier extraherades vid efter-träning, återhämtningsperiod, och efter 24 timmar. Resultat: Natriumlaktat respektive saltlösnings infusion under styrketräning gav signifikant högre blodlaktat med natriumlaktat infusion (6.78 ± 0.33 mmol/l mot 2.99 ± 0.17 mmol/l), plasmalaktat (8.86 ± 0.39 mmol/l mot 4.39 ± 0.22 mmol/l), blodnatrium (143 ± 0.4 mmol/l mot 142 ± 0.3 mmol/l), blod pH (7.42 ± 0.01 mot 7.34 ± 0.01), men lägre blod kalium (3.9 ± 0.1 mmol/l mot 4.2 ± 0.1 mmol/l), alla direkt efter träning. Natriumlaktat infusion framkallade huvudeffekt av försök och muskellaktat ökade från baslinje (8.5 ± 0.9 mmol·kg-1 dw mot 7.0 ± 0.6 mmol·kg-1 dw) till efter-träning (31.5 ± 2.8 mmol·kg-1 dw mot 26.9 ± 3.2 mmol·kg-1 dw) med natriumlaktat respektive saltlösnings infusion. Blodglukos, hemoglobin och muskel pH påverkades inte av natriumlaktat infusion. Slutsats: Användande av natriumlaktat infusion som metod under styrketräning kan effektivt användas som verktyg för att höja blod/plasma laktat, och i mindre utsträckning, muskellaktat. Emellertid är samtidig alkalisering av blod en sannolik följd. / Potential sex differences in the molecular response to resistance exercise with lactate infusion

Made available in DSpace on 2014-07-29T15:13:39Z (GMT). No. of bitstreams: 1 Yandra Cassia Lobato do Prado.pdf: 3346090 bytes, checksum: 459271b973e2cf45dae272f74f535fe4 (MD5) Previous issue date: 2010-06-10 / Primates are known for larger brain size, enhanced handling and cognitive abilities and increasingly complex social behavior. Many studies have been conducted with the neotropical primates of the genus Cebus, known as capuchin monkey, regarding their behavior, tool use, encephalization index and memory. These studies are justified because these primates present high cognitive faculty and other biological characteristics that make them similar to Old World primates. This thesis rendered possible the production of two articles. The first one is entitled Anatomical description of the extensor muscles of the forearm associated with cognition and tool use in Cebus libidinosus . In this article, a comparative analysis between the anatomy of the forearm muscle of this genus and that the one of other primates that, individually or jointly, act in the hands allowing more or less specialized movements of the fingers, relating them to the use of tools and to the cognitive aspects of Cebus spp. described in the literature. There were evident similarities between the extensor muscles in C. libidinosus primates and the correspondent muscles in humans and chimpanzees; however, there were differences when compared to baboons. The structure and differentiation of the forearm muscles of Cebus spp., together with its previously known encephalization index, corroborate the association between its manual ability and cognitive and behavioral aspects in primates. The second article is entitled "Cytoarchitecture of the occipital neocortex of Cebus libidinosus . Its purpose was to analyze the cytoarchitecture of the occipital cortex using the technique of Golgi-Cox, the qualitative and quantitative aspects provided by this technique of impregnation of neurons, and to compare them with data from the literature. Primary and secondary visual areas are located in the occipital neocortex, and in C. libidinosus, the histological organization of these areas is similar to humans and other primates and it is characterized by the predominance of granular neurons and the presence of transversal fibers in the fourth layer. Although the Golgi-Cox method allowed individual observation of neurons and their extensions, the weak distinction between neurons and glial cells impaired neuron counting. These data, nevertheless, will grant further cell density comparison of other cortical areas between Cebus spp. and other primates. Aiming to contribute to the foundations of studies related to the evolution of primate cognition, this study related morphology, as a science, to the numerous observations on the behavior of capuchin monkeys. The comparative approach to study the morphology of the musculoskeletal and neural apparatus of C. libidinosus will allow data inference in areas of cognitive science and related areas. / Os primatas são caracterizados pelo maior tamanho do cérebro, pelo aprimoramento de habilidades manipulativas e cognitivas e desenvolvimento de comportamento social complexo. Muitos estudos têm sido realizados com os primatas neotropicais do gênero Cebus, conhecidos por macaco-prego, relativos a comportamento e uso de ferramentas, índice de encefalização e memória. Esses estudos se justificam em razão desses primatas apresentarem elevada capacidade cognitiva e outras características biológicas que os torna similares aos primatas do Velho Mundo. A presente tese gerou a produção de dois artigos. O primeiro intitulado Descrição anatômica dos músculos extensores do antebraço de Cebus libidinosus associada a aspectos cognitivos e ao uso de ferramentas , propôs-se a análise comparativa entre a anatomia muscular do antebraço com àquela de outros primatas que, individual ou conjuntamente, atuam nas mãos possibilitando movimentos mais ou menos especializados dos dedos, relacionando-se ao uso de ferramentas e aspectos cognitivos de Cebus spp. descritos na literatura. Observaram-se evidentes similaridades entre os músculos extensores de C. libidinosus com os músculos correspondentes em humanos e chimpanzés, porém houve diferenças desses músculos em relação aos babuínos. A estrutura e diferenciação dos músculos do antebraço do Cebus spp., associados ao seu já conhecido índice de encefalização, reforçam a associação entre suas habilidades manuais e os aspectos cognitivos e comportamentais em primatas. O segundo artigo intitulado Citoarquitetura do neocórtex occipital de Cebus libidinosus propôs-se a análise da citoarquitetura do córtex cerebral occipital utilizando a técnica de Golgi-Cox, sob os aspectos qualitativos e quantitativos que esta técnica de impregnação de neurônios proporciona e, compará-los com dados descritos na literatura. No neocórtex occipital estão situadas as áreas visuais primárias e secundárias e, em C. libidinosus, a organização histológica destas áreas apresenta, tal como em outros primatas não-humanos e o homem, a predominância de neurônios granulares e a presença de estrias de Baillarger na quarta camada. O emprego da técnica de Golgi-Cox permitiu a visualização individual dos neurônios e seus prolongamentos, entretanto quanto à análise quantitativa apresenta como limitação a dificuldade em diferenciar células neuronais e não-neuronais. Estes dados permitirão futuras comparações entre diferentes áreas corticais de Cebus spp. e outros primatas. Com o intuito de contribuir com as bases dos estudos relacionados à evolução da cognição de primatas, este trabalho relacionou a morfologia, tal como ciência que é, com as inúmeras observações sobre comportamento do macaco-prego. A abordagem comparativa no estudo da morfologia músculo-esquelética e do aparato neural do C. libidinosus permitirá inferir dados às áreas da ciência cognitiva e áreas correlatas.