Дисертації з теми "Slow component of VO2"

Established models of endurance performance (Costill et al. (1973) Med Sci Sports 5(4): 248-252 and Coyle (1995) Ex. Sport Sci. Rev. 23:25-63) are based on the athlete's ability to maintain a fixed %V02peak, normally within the severe intensity domain, e.g. 88 %V02peak (exercise intensity domains being defined as; rest-moderate-heavy-severe-V02peak; Whipp (1994) Med. Sci. Sports Exerc. 26(11): 1319-13-26). The V02 slow component (V02SC) concept (Gaesser and Poole, 1996, Ex. Sport Sci. Rev. 24:35-70), which is based on observations from a healthy/sedentary populations', states that V02 continually increases within the severe intensity domain, and therefore undermines the validity of the performance models. This thesis examined the V02SC in an endurance trained cyclist population. Within the models, V02peak sets the ceiling for endurance performance. Current V02SC theory suggests that V02p"k assessment is protocol independent, as V02 continually increases within the severe intensity domain. This thesis demonstrated that V02peak was protocol dependent for 3 ramp protocols (35, 20 and 5 W.min-'), the V02SC being unable to generate a V02peak response from the 5 W.min-' protocol even though the subjects worked within the severe intensity domain. The V02SC definition states that V02 is elevated above values predicted from moderate intensity exercise at heavy, and increases continually, at severe exercise intensities. The endurance trained subjects demonstrated elevated steady state V02 responses at exercise intensities up to their endurance performance V02. This was within the severe intensity domain, thus validating the performance models for this subject population. The V02SC response in endurance trained cyclists differed from that previously observed for a sedentary/healthy population, therefore the currently accepted cause, increased fast twitch (FT) muscle fibre recruitment, may be questioned. Evidence from EMG studies suggest that muscle recruitment patterns differ between muscles, with increasing intensity (Green and Patla (1992) Med. Sci. Sports Ex. 24(1): 38-46). The recruitment patterns of three muscles were examined during incremental exercise to establish changes in both the magnitude of activation, and potential changes in fibre type recruitment (via the median frequency response). The pattern of muscle recruitment varied between both subjects and muscles. Changes in the recruitment patterns of a number of individual muscles were coincidental with the initiation of the V02SC. No coincidence between muscle fibre type recruitment (assessed via the EMG median frequency response) and the V02SC in endurance trained cyclists was observed. Therefore the V02SC may be due to changes in muscle recruitment patterns as well as FT fibre recruitment. The results of this thesis suggest that current models of endurance performance are valid for the endurance trained cyclist population studied, and that the V02SC concept should be redefined for this population. The V02SC response observed may be due to changes in muscle recruitment patterns and an increase in the number of motor units recruited, as median frequency EMG measures did not support the hypothesis that the V02SC is principally caused by an increased recruitment of FT muscle fibres.

L'objectif de cette thèse était triple 1)- Etudier la fonction ventilatoire durant un exercice incrémental maximal et un exercice sous-maximal prolongé chez des sportifs porteurs de trait drépanocytaire (PTD) 2)- Etudier la performance de la fonction ventilatoire durant un exercice à charge constante chez des sujets ayant une β-thalassémie mineure, 3)- Evaluer l'adaptation physiologique durant un effort sous-maximal prolongé chez des sportifs atteints de drépanocytose hétérozygote. La première étude a montré que l'exercice incrémental maximal et l'exercice à charge constante induisent une fatigue spirométrique, de la force et de l'endurance des muscles respiratoires chez les sujets porteurs de trait drépanocytaire. L'exercice rectangulaire affecte de façon importante la force et l'endurance musculaire respiratoire que l'exercice triangulaire. La deuxième étude a montré par ailleurs, une altération de la performance de la fonction ventilatoire après la réalisation d'un exercice sous-maximal prolongé chez les sujets ayant une β-thalassémie mineure. Ainsi, une diminution importante de l'endurance des muscles respiratoires a été constatée chez ces individus pathologiques en réponse à l'exercice à charge constante par rapport aux sujets sains. Ces résultats confirment que les sujets ayant des hémoglobinopathies n'ont pas la capacité de maintenir des niveaux élevés de ventilation pendant un exercice physique intense. Ensuite, lors de la troisième étude, la détermination de la PMA a permis d'affirmer que la forme hétérozygote de la drépanocytose n'est pas un facteur limitant de l'aptitude physique aérobie maximale. L'adaptation à un effort sous-maximal, évaluée par la phase rapide est parfaitement normale chez les sujets ayant un trait drépanocytaire. Par contre, l'amplitude de la composante lente de VO2, plus élevée chez les PTD suggère que ces individus pathologiques se caractérisent par une mauvaise tolérance à l'effort. Cette élévation était corrélée avec l'HbO2 et HHb qui étaient stables durant l'effort. Cette stabilité confirme la génération du mécanisme de remodelage vasculaire chez les PTD en réponse à des problèmes hémorhéologiques produits par l'effort. Une augmentation précoce du RMS et une diminution linéaire de 25,63% de MPF corrélée avec HHb, ont été constatées durant l'effort chez les individus pathologiques par rapport aux sujets sans hémoglobinopathie, affirmant que la baisse de déformabilité des globules rouges dont sont signalés généralement les sujets porteurs de trait drépanocytaire bouleverse de façon accrue la microcirculation musculaire qui pourrait être responsable de la composante lente de VO2. Ces résultats montrent que les sujets ayant une hémoglobinopathie pourraient avoir une fonction ventilatoire moins performante durant un effort physique intense que les sujets sains. Également, ces individus pourraient avoir une fatigue musculaire périphérique plus importante que les sujets à hémoglobine normale et une oxygénation musculaire stable durant un exercice rectangulaire. Ils présentent une capacité aérobie et une tolérance à l'effort d'endurance, inférieures aux sujets sains durant un effort sous-maximal
The aim of this thesis was threefold 1)- To study the ventilatory function during a maximal incremental exercise and a prolonged submaximal exercise in athletes with sickle cell trait (SCT), 2)- To study the performance of the ventilatory function during a constant load exercise in subjects with minor β-thalassemia, 3)- Evaluate the physiological adaptation during prolonged submaximal exercise in athletes with heterozygous sickle cell disease. The first study showed that maximal incremental exercise and constant load exercise induce spirometric fatigue, and decreased strength and endurance of the respiratory muscles in subjects with sickle cell trait. Rectangular exercise significantly affects respiratory muscle strength and endurance than triangular exercise. The second study was showed an impairment of the performance of ventilatory function after performing prolonged submaximal exercise in subjects with minor β-thalassemia. Thus, a significant decrease in the endurance of the respiratory muscles was observed in these pathological individuals in response to constant load exercise compared to healthy subjects. These results confirm that hemoglobinopathic subjects do not have the ability to maintain high levels of ventilation during intense physical exercise. Then, in the third study, the determination of the MAP confirmed that the heterozygous form of sickle cell disease is not a limiting factor in maximal aerobic physical fitness. Adaptation to submaximal effort, assessed by the rapid phase, is perfectly normal in subjects with sickle cell trait. In contrast, the amplitude of the slow component of VO2, which is higher in SCT, suggests that these pathological individuals are characterized by weak tolerance to exercise. This rise was correlated with HbO2 and HHb which were satble during exercise. This stability confirms the generation of the vascular remodeling mechanism in SCT in response to hemorheological problems produced by exercise. An precocious increase in RMS and a 25.63% linear decrease in MPF correlated with HHb, were observed during exercise in pathologic individuals compared to subjects without hemoglobinopathy, affirming that the decrease in erythrocyte deformabilities which are generally reported in subjects with sickle cell trait disrupts the muscular microcirculation in an increased manner which could be responsible for the slow component of VO2. These results show that subjects with hemoglobinopathy could have a less efficient ventilatory function during intense physical exertion than healthy subjects. Also, these individuals might have more significant peripheral muscle fatigue than subjects with normal hemoglobin and stable muscle oxygenation during rectangular exercise. They exhibit aerobic capacity and tolerance to endurance effort inferior than healthy subjects during submaximal effort

Der Fokus dieser Dissertation liegt auf den Verbindungen zwischen ICA (Independent Component Analysis - Unabhängige Komponenten Analyse) und SFA (Slow Feature Analysis - Langsame Eigenschaften Analyse). Um einen Vergleich zwischen beiden Methoden zu ermöglichen wird CuBICA2, ein ICA Algorithmus basierend nur auf Statistik zweiter Ordnung, d.h. Kreuzkorrelationen, vorgestellt. Dieses Verfahren minimiert zeitverzögerte Korrelationen zwischen Signalkomponenten, um die statistische Abhängigkeit zwischen denselben zu reduzieren. Zusätzlich wird eine alternative SFA-Formulierung vorgestellt, die mit CuBICA2 verglichen werden kann. Im Falle linearer Gemische sind beide Methoden äquivalent falls nur eine einzige Zeitverzögerung berücksichtigt wird. Dieser Vergleich kann allerdings nicht auf mehrere Zeitverzögerungen erweitert werden. Für ICA lässt sich zwar eine einfache Erweiterung herleiten, aber ein ähnliche SFA-Erweiterung kann nicht im originären SFA-Sinne (SFA extrahiert die am langsamsten variierenden Signalkomponenten aus einem gegebenen Eingangssignal) interpretiert werden. Allerdings kann eine im SFA-Sinne sinnvolle Erweiterung hergeleitet werden, welche die enge Verbindung zwischen der Langsamkeit eines Signales (SFA) und der zeitlichen Vorhersehbarkeit desselben verdeutlich. Im Weiteren wird CuBICA2 und SFA kombiniert. Das Resultat kann aus zwei Perspektiven interpretiert werden. Vom ICA-Standpunkt aus führt die Kombination von CuBICA2 und SFA zu einem Algorithmus, der das Problem der nichtlinearen blinden Signalquellentrennung löst. Vom SFA-Standpunkt aus ist die Kombination eine Erweiterung der standard SFA. Die standard SFA extrahiert langsam variierende Signalkomponenten die untereinander unkorreliert sind, dass heißt statistisch unabhängig bis zur zweiten Ordnung. Die Integration von ICA führt nun zu Signalkomponenten die mehr oder weniger statistisch unabhängig sind.
Within this thesis, we focus on the relation between independent component analysis (ICA) and slow feature analysis (SFA). To allow a comparison between both methods we introduce CuBICA2, an ICA algorithm based on second-order statistics only, i.e.\ cross-correlations. In contrast to algorithms based on higher-order statistics not only instantaneous cross-correlations but also time-delayed cross correlations are considered for minimization. CuBICA2 requires signal components with auto-correlation like in SFA, and has the ability to separate source signal components that have a Gaussian distribution. Furthermore, we derive an alternative formulation of the SFA objective function and compare it with that of CuBICA2. In the case of a linear mixture the two methods are equivalent if a single time delay is taken into account. The comparison can not be extended to the case of several time delays. For ICA a straightforward extension can be derived, but a similar extension to SFA yields an objective function that can not be interpreted in the sense of SFA. However, a useful extension in the sense of SFA to more than one time delay can be derived. This extended SFA reveals the close connection between the slowness objective of SFA and temporal predictability. Furthermore, we combine CuBICA2 and SFA. The result can be interpreted from two perspectives. From the ICA point of view the combination leads to an algorithm that solves the nonlinear blind source separation problem. From the SFA point of view the combination of ICA and SFA is an extension to SFA in terms of statistical independence. Standard SFA extracts slowly varying signal components that are uncorrelated meaning they are statistically independent up to second-order. The integration of ICA leads to signal components that are more or less statistically independent.

Eighteen untrained males [age: 23 +/- 0.6 yr (SEM)] were randomized into high intensity (HIT: above lactate threshold, LT), moderate intensity (LIT: below the LT) or no training (NT) groups. Subjects trained on a cycle ergometer 4 days.wk-1 for 6 wk with the power output held constant. Maximal cycle ergometry was performed before and after the training period to determine changes in power output and oxygen consumption (VO2) at the LT and peak exertion. Before training and after 1, 2, 4, and 6 wk, subjects performed high constant-load (HCL) cycling bouts to quantify training adaptations in the SC. Training was designed to keep total work equivalent between the HIT and LIT groups. Increases in power output and VO2 at LT and peak exercise after 6 wk were noted in the HIT and LIT groups in comparison to NT group (p<0.05). No differences were noted between HIT and LIT. Two-way repeated measures ANOVA revealed a significant trial*group interaction for adaptation in the SC (p<0.001). After 1wk of training, a significant reduction in the SC was noted for HIT [mean+/-SEM]: (pre-training (PT): 703 +/- 61 ml.min-1; 1 wk: 396 +/- 60 ml.min-1) (- 44% from PT). Further adaptation for the HIT was also noted at 4 wk: 202 +/- 45 ml.min-1 (-71% from PT). For LIT, a significant reduction was noted at 2 wk (PT: 588+/-76 ml.min-1; 2 wk: 374 +/- 50ml.min-1) (-36% from PT). Further adaptation for LIT group was noted at 6 wk (252 +/- 38 ml.min-1) (- 57% from PT). Adaptation in SC was not noted at any interval for NT. Temporal changes in blood lactate (r = 0.40) and ventilation (r = 0.72) were significantly correlated with the changes for SC over the 6 wk training period (p<0.05). In conclusion, it was demonstrated that training at supra-LT and sub-LT intensities produces similar improvement in VO2 and power output at peak exercise and in the LT, when total work output is controlled. However, training at supra-LT intensity promotes larger and faster adaptations in the SC than training at the sub-LT levels.
Ph. D.

Orientador: Benedito Sérgio Denadai
Banca: Mara Patrícia T. Chacon-Mikahil
Banca: Miguel de Arruda
Banca: Luiz Guilherme Antonacci Guglielmo
Banca: Emerson Franchini
Resumo: A cinética do consumo de oxigênio (V02) descreve o comportamento respiratório durante a transição repouso-exercício. Os parâmetros derivados dos ajustes (componente lento - CL e constante de tempo - t ou Tau) são utilizados para quantificar a magnitude das alterações ocorridas nesse sistema. Os objetivos deste estudo foram: 1) verificar a influência de diferentes modelos de análise [modelo matemático com três termos exponenciais (Exp3) vs. diferença do V02 entre o sexto e o terceiro minuto de exercício (AVO2 6-3 mm)] na caracterização do CL durante o exercício acima do limiar de lactato (LL) em corrida; 2) verificar os efeitos do tipo de exercício [corrida em esteira rolante (ER) vs. exercício em bicicleta ergométrica (BE)] no pico do consumo de oxigênio (VO210) e LL (expresso em ml/kg/mim e % VO2pjc) e; 3) verificar os efeitos do tipo de exercício no tVO2 e no CL da cinética do V02 durante o exercício acima do LL em meninos de 11-12 anos de idade. Participaram do estudo 20 crianças do gênero masculino aparentemente saudáveis e ativos (11,48 l 0,41 anos; 41,38 l 10,45 kg; 147,45 l 6,56 cm), nível maturacional 1 e 2 (pilosidade pubiana) que realizaram dois testes incrementais, um na ER e outro na BÊ para determinação do VO20 e do LL. Para determinação da cinética do VO2 foram realizadas duas transições de 6 minutos em cada ergômetro na intensidade de 75%A [75% A = LL + 0,75 x (VO2pico - LL)]... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The oxygen uptake kinetic (V02) explaian the respiratory behavior during restexercise transition. The parameters from the adjustment (slow component - SC and time constant - t or Tau) are usual to measure the magnitude of the alterations on this structure. The objectives of this study were: 1) to verify the influence of the two different mathematical models [three-exponential model (Exp3) and AVO2 6-3 mm] on the SC of V02 in children during running exercise, performed at above lactate threshold intensity domain (75%A); 2) to verify the effects of exercise mode (running x cycling) on the indexes related to aerobic fitness (VO2peak and blood lactate response to exercise); 3) to verify the effect of the exercise mode (running x cycling) on the tVO2 and the SC of the VO2 in children aged 11 to 12 years during above lactate threshold intensity exercise (75%). Twenty apparently healthy active boys (age = 11,48 l 0,41 years; body mass = 41,38 l 10,45 kg; hemght = 147,45 l 6,56 cm), sexual maturation levels 1 and 2 (pubic hair) took part of this study. These children performed in different days on a motorized treadmill (TM) and on a cycle ergometer (CE) the following tests: 1) an incremental test in order to determine the peak oxygen uptake (VO2peak) and the LT and; 2) a series of square-wave transitions of 6-min \- 02peak - iJ1) 111 OTT 'Lo Õe'Lerffilne Yne V02 kinetics (tVO2 and SC). The SC values determined by model Exp3 (129,69 l 75,71 mi/min and 8,4 l 2,92 %) were higher than values determined by model VO2 6-3 mm (68,69 l 102,54 mi/min and 3,6 l 7,34%)... (Complete abstract click electronic access below)
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A cinética do consumo de oxigênio (V02) descreve o comportamento respiratório durante a transição repouso-exercício. Os parâmetros derivados dos ajustes (componente lento - CL e constante de tempo - t ou Tau) são utilizados para quantificar a magnitude das alterações ocorridas nesse sistema. Os objetivos deste estudo foram: 1) verificar a influência de diferentes modelos de análise [modelo matemático com três termos exponenciais (Exp3) vs. diferença do V02 entre o sexto e o terceiro minuto de exercício (AVO2 6-3 mm)] na caracterização do CL durante o exercício acima do limiar de lactato (LL) em corrida; 2) verificar os efeitos do tipo de exercício [corrida em esteira rolante (ER) vs. exercício em bicicleta ergométrica (BE)] no pico do consumo de oxigênio (VO210) e LL (expresso em ml/kg/mim e % VO2pjc) e; 3) verificar os efeitos do tipo de exercício no tVO2 e no CL da cinética do V02 durante o exercício acima do LL em meninos de 11-12 anos de idade. Participaram do estudo 20 crianças do gênero masculino aparentemente saudáveis e ativos (11,48 l 0,41 anos; 41,38 l 10,45 kg; 147,45 l 6,56 cm), nível maturacional 1 e 2 (pilosidade pubiana) que realizaram dois testes incrementais, um na ER e outro na BÊ para determinação do VO20 e do LL. Para determinação da cinética do VO2 foram realizadas duas transições de 6 minutos em cada ergômetro na intensidade de 75%A [75% A = LL + 0,75 x (VO2pico - LL)]...
The oxygen uptake kinetic (V02) explaian the respiratory behavior during restexercise transition. The parameters from the adjustment (slow component - SC and time constant - t or Tau) are usual to measure the magnitude of the alterations on this structure. The objectives of this study were: 1) to verify the influence of the two different mathematical models [three-exponential model (Exp3) and AVO2 6-3 mm] on the SC of V02 in children during running exercise, performed at above lactate threshold intensity domain (75%A); 2) to verify the effects of exercise mode (running x cycling) on the indexes related to aerobic fitness (VO2peak and blood lactate response to exercise); 3) to verify the effect of the exercise mode (running x cycling) on the tVO2 and the SC of the VO2 in children aged 11 to 12 years during above lactate threshold intensity exercise (75%). Twenty apparently healthy active boys (age = 11,48 l 0,41 years; body mass = 41,38 l 10,45 kg; hemght = 147,45 l 6,56 cm), sexual maturation levels 1 and 2 (pubic hair) took part of this study. These children performed in different days on a motorized treadmill (TM) and on a cycle ergometer (CE) the following tests: 1) an incremental test in order to determine the peak oxygen uptake (VO2peak) and the LT and; 2) a series of square-wave transitions of 6-min \- 02peak - iJ1) 111 OTT 'Lo Õe'Lerffilne Yne V02 kinetics (tVO2 and SC). The SC values determined by model Exp3 (129,69 l 75,71 mi/min and 8,4 l 2,92 %) were higher than values determined by model VO2 6-3 mm (68,69 l 102,54 mi/min and 3,6 l 7,34%)... (Complete abstract click electronic access below)

The primary aim of this thesis was to develop a better understanding of the physiology and perceptual responses associated with the performance of continuous (CE) and intermittent exercise (IE) in patients with moderate chronic obstructive pulmonary disease (COPD). A secondary aim was to examine factors that could potentially limit exercise tolerance in COPD patients, particularly in relation to the dynamics of the cardiovascular system and muscle metabolism. The results of the four studies conducted to achieve these aims are presented in this thesis. In Study 1, the physiological, metabolic and perceptual responses to an acute bout of IE and CE were examined in 10 individuals with moderate COPD. Each subject completed an incremental exercise test to exhaustion on a cycle ergometer. Subjects then performed IE (1 min exercise: 1 min rest ratio) and CE tests at 70% of peak power in random order on separate days. Gas exchange, heart rate, plasma lactate concentration, ratings of breathlessness, inspiratory capacity and the total amount of work completed were measured during each exercise test. Subjects were able to complete a significantly greater amount of work during IE (71 ± 32 kJ) compared with CE (31 ± 24 kJ). Intermittent exercise was associated with significantly lower values for oxygen uptake, expired ventilation and plasma lactate concentration when compared with CE. Subjects also reported a significantly lower rating of breathlessness during IE compared to CE. The degree of dynamic lung hyperinflation (change in end-expiratory lung volume) was lower during IE (0.23 ± 0.07 L) than during CE (0.52 ± 0.13 L). The results suggest that IE may be superior to CE as a mode of training for patients with COPD. The greater amount of total work performed and the lower measured physiological responses attained with intermittent exercise could potentially allow greater training adaptations to be achieved in individuals with more limited lung function. The purpose of Study 2 was to compare the adaptations to 8 wk of supervised intermittent and continuous cycle ergometry training, performed at the same relative intensity and matched for total work completed, in patients with COPD. Nineteen subjects with moderate COPD were stratified according to age, gender, and pulmonary function, and then randomly assigned to either an IE (1 min exercise: 1 min rest ratio) or CE training group. Subjects trained 3 d per week for 8 wk and completed 30 min of exercise. Initial training intensity, i.e., the power output applied during the CE bouts and during the exercise interval of the IE bouts, was determined as 50% of the peak power output achieved during incremental exercise and was increased by 5% each week after 2 wk of training. The total amount of work performed was not significantly different (P=0.74) between the CE (750 ± 90 kJ) and IE (707 ± 92 kJ) groups. The subjects who performed IE (N=9) experienced significantly lower levels of perceived breathlessness and lower limb fatigue during the exercise-training bouts than the group who performed CE (N=10). However, exercise capacity (peak oxygen uptake) and exercise tolerance (peak power output and 6-min walk distance) improved to a similar extent in both training groups. During submaximal constant-load exercise, the improved (faster) phase II oxygen uptake kinetic response with training was independent of exercise mode. Furthermore, training-induced reductions in submaximal exercise heart rate, carbon dioxide output, expired ventilation and blood lactate concentrations were not different between the two training modes. Exercise training also resulted in an equivalent reduction for both training modes in the degree of dynamic hyperinflation observed during incremental exercise. Thus, when total work performed and relative intensity were the same for both training modes, 8 wk of CE or IE training resulted in similar functional improvements and physiological adaptations in patients with moderate COPD. Study 3 examined the relationship between exercise capacity (peak oxygen uptake) and lower limb vasodilatory capacity in 9 patients with moderate COPD and 9 healthy age-matched control subjects. While peak oxygen uptake was significantly lower in the COPD patients (15.8 ± 3.5 mL·min-1·kg-1) compared to the control subjects (25.2 ± 3.5 mL·kg-1·min-1), there were no significant differences between groups in peak calf blood flow or peak calf conductance measured 7 s post-ischemia. Peak oxygen uptake was significantly correlated with peak calf blood flow and peak conductance in the control group, whereas there was no significant relationship found between these variables in the COPD group. However, the rate of decay in blood flow following ischemia was significantly slower (p less than 0.05) for the COPD group (-0.036 ± 0.005 mL·100 mL-1·min-1·s-1) when compared to the control group (-0.048 ± 0.015 mL·100 mL-1·min-1·s-1). The results of this study suggest that the lower peak exercise capacity in patients with moderate COPD is not related to a loss in leg vasodilatory capacity. Study 4 examined the dynamics of oxygen uptake kinetics during high-intensity constant-load cycling performed at 70% of the peak power attained during an incremental exercise test in 7 patients with moderate COPD and 7 healthy age-matched controls. The time constant of the primary component (phase II) of oxygen uptake was significantly slower in the COPD patients (82 ± 8 s) when compared to healthy control subjects (44 ± 4 s). Moreover, the oxygen cost per unit increment in power output for the primary component and the overall response were significantly higher in patients with COPD than in healthy control subjects. A slow component was observed in 5 of the 7 patients with COPD (49 ± 11 mL·min-1), whereas all of the control subjects demonstrated a slow component of oxygen uptake (213 ± 35 mL·min-1). The slow component comprised a significantly greater proportion of the total oxygen uptake response in the healthy control group (18 ± 2%) than in the COPD group (10 ± 2%). In the COPD patients, the slow component amplitude was significantly correlated with the decrease in inspiratory capacity (r = -0.88, P less than 0.05; N=5), indicating that the magnitude of the slow component was larger in individuals who experienced a greater degree of dynamic hyperinflation. This study demonstrated that most patients with moderate COPD are able to exercise at intensities high enough to elicit a slow component of oxygen uptake during constant-load exercise. The significant correlation observed between the slow component amplitude and the degree of dynamic hyperinflation suggests that the work of breathing may contribute to the slow component in patients with COPD.

L'objectif de cette thèse a été premièrement de réaliser des dispositifs passifs intégrés à base de lignes à onde lentes nommées S-CPW (pour " Slow-wave CoPlanar Waveguide ") aux fréquences millimétriques. Plusieurs technologies CMOS ou BiCMOS ont été utilisées: CMOS 65 nm et 28 nm ainsi que BiCMOS 55 nm. Deux baluns, le premier basé sur une topologie de rat-race et le second basé sur un diviseur de puissance de Wilkinson modifié, ainsi qu'un inverseur de phase, ont été réalisés et mesurés dans la technologie CMOS 65 nm. Les résultats expérimentaux obtenus se situent à l'état de l'art en termes de performances électriques. Un coupler hybride et un diviseur de puissance avec des sorties en phase sans isolation ont été conçus en technologie CMOS 28 nm. Les simulations montrent de très bonnes performances pour des dispositifs compacts. Les circuits sont en cours de fabrication et pourront très bientôt être caractérisés. Ensuite, une nouvelle topologie de diviseurs de puissance, avec sorties en phase et isolé a été développée, offrant une grande flexibilité et compacité en comparaison des diviseurs de puissance traditionnels. Cette topologie est parfaitement adaptée pour les technologies silicium. Comme preuve de concept, deux diviseurs de puissance avec des caractéristiques différentes ont été réalisés en technologie PCB microruban à la fréquence de 2.45 GHz. Un composent a été conçu à 60 GHz en technologie BiCMOS 55 nm utilisant des lignes S CPW. Les simulations prouvent que le dispositif est faibles pertes, adapté et isolé. Les circuits sont également en cours de fabrication. Enfin, deux topologies de " reflection type phase shifter " ont été développées, la première dans la bande RF et la seconde aux fréquences millimétrique. Pour la bande RF, le déphasage atteint plus de 360° avec une figure de mérite très élevée en comparaison avec l'état de l'art. En ce qui concerne le déphaseur dans la bande millimétrique, la simulation montre un déphasage de 341° avec également une figure de mérite élevée.

In dieser Arbeit werden - basierend auf dem Langsamkeitsprinzip - Modelle und Algorithmen für das auditorische System entwickelt. Verschiedene experimentelle Ergebnisse, sowie die erfolgreichen Ergebnisse im visuellen System legen nahe, dass, trotz der unterschiedlichen Beschaffenheit visueller und auditorischer sensorischer Signale, das Langsamkeitsprinzip auch im auditorischen System eine bedeutsame Rolle spielen könnte, und vielleicht auch im Kortex im Allgemeinen. Es wurden verschiedene Modelle für unterschiedliche Repräsentationen des auditorischen Inputs realisiert. Es werden die Beschränkungen der jeweiligen Ansätze aufgezeigt. Im Bereich der Signalverarbeitung haben sich das Langsamkeitsprinzip und dessen direkte Implementierung als Signalverarbeitungsalgorithmus, Slow Feature Analysis, über die biologisch inspirierte Modellierung hinaus als nützlich erwiesen. Es wird ein neuer Algorithmus für das Problem der nichtlinearen blinden Signalquellentrennung beschrieben, der auf einer Kombination von Langsamkeitsprinzip und dem Prinzip der statistischen Unabhängigkeit basiert, und der anhand von künstlichen und realistischen Audiosignalen getestet wird. Außerdem wird die Open Source Software Bibliothek Modular toolkit for Data Processing vorgestellt.
In this thesis we develop models and algorithms based on the slowness principle in the auditory domain. Several experimental results as well as the successful results in the visual domain indicate that, despite the different nature of the sensory signals, the slowness principle may play an important role in the auditory domain as well, if not in the cortex as a whole. Different modeling approaches have been used, which make use of several alternative representations of the auditory stimuli. We show the limitations of these approaches. In the domain of signal processing, the slowness principle and its straightforward implementation, the Slow Feature Analysis algorithm, has been proven to be useful beyond biologically inspired modeling. A novel algorithm for nonlinear blind source separation is described that is based on a combination of the slowness and the statistical independence principles, and is evaluated on artificial and real-world audio signals. The Modular toolkit for Data Processing open source software library is additionally presented.

The aim of master's thesis is to get familiarized with the problems of measurement and analysis of seismic waves. Theoretical part deals with the description of seismic waves, especially their types, sources and properties. Attention was afterwards focused on the measurement systems of these waves, emphasis was placed on their principles and advantages. The practical part discusses methods of noise reduction and highlighting of significant events in measured data. At the end, individual methods are implemented into user-friendly graphical interface.

碩士
國立臺灣大學
化學研究所
105
Photodissociation of phenol has been investigated by both experimental and theoretical methods for the past few decades since it is an important model molecular of multistate dissociation. The major photofragments in UV region are Hydrogen atom plus phenoxyl radical produced through OH bond fission. Previous experiments showed that there are two components, namely fast and slow, in the photofragment translational energy distributions. The fast component was assigned as dissociation in the electronic excited state forming the ground state phenoxyl radical. As for the slow component, it can be assigned as (1) dissociation in the electronic excited state forming the excited state phenoxyl radical, or (2) internal conversion followed by dissociation in the electronic ground state. There was no experimental measurement of branching ratio for these two channels before. In this work, we have performed a new type of time-resolved experiment using modified conventional photofragment translational spectroscopy to get the time-resolved spectra of photofragment translational energy. The results show clear characteristic of three different dissociation channels. The first channel producing a component centered at ~12000 cm-1 in translational energy distribution has a lifetime < 10 ns, and is assigned as dissociation in the excited state forming the ground state phenoxyl radical. The second channel generates a component centered at ~2000 cm-1 in translational energy distribution with a lifetime < 10 ns, and is assigned as dissociation in the excited state forming the excited state phenoxyl radical. The third channel producing a component mainly below 3000 cm-1 in translational energy distribution has a lifetime > 100 ns, and is assigned as dissociation in the ground state forming the excited state phenoxyl radical. Finally, we get the branching ratio of ground state dissociation channel and excited state dissociation channel forming phenoxyl radical X,A,B state for the photodissociation of phenol at 193nm as 0.05, 0.53, 0.24, 0.17, and at 213 nm as 0.07, 0.60, 0.32, 0. These branching ratios are useful for justifying the results of theoretical calculations. Furthermore, this technique is useful for the investigation of photodissocition of other molecules which would also dissociate on the multi potential energy surface.

DNA double-strand breaks (DSBs) represent the most deleterious type of DNA damage as they pose a serious threat to genome integrity. Two major pathways are available for the repair of DSBs: canonical non-homologous end joining (c-NHEJ) and homologous recombination (HR). During c-NHEJ, the DSB ends are re-ligated after minimal end processing steps. The HR pathway is more complex and is initiated by CtIP-dependent DSB end resection to form 3’ ssDNA overhangs for subsequent homology search in the sister chromatid. In wild type human G1-phase cells only c-NHEJ is available for DSB repair, as in this cell cycle phase the homologous sister chromatid required for HR is missing. DSB repair in G1, as well as in G2, shows biphasic kinetics consisting of a fast component that repairs the majority of breaks within the first few hours after damage induction, followed by a slow component that repairs the remaining breaks. The fast component in both G1 and G2 phase is well characterized and represents c-NHEJ, while the slow component in G2 represents repair by HR. Previous work has suggested that the slow repair component in G1 represents a sub-pathway of NHEJ that requires the activities of Artemis and ATM. However, the mechanism underlying the slow repair component in G1 is not fully understood and its characterization was the focus of this work. To specifically study slow repair in G1, high LET α-particle radiation was used to induce complex DNA damages that are repaired with slow kinetics. RPA rapidly binds ssDNA in the cell to protect it from nucleolytic degradation and is phosphorylated in response to DNA damage. Exploiting the qualities of α–particle radiation, an assay was developed to monitor pRPA-foci formation in G1 and used as a tool to measure DSB end resection in this cell-cycle phase. Another approach to study the slow repair component was the quantification of γH2AX foci, a histone modification in response to DSBs, at late time points post IR. Collectively, it was shown that slowly repairing DSBs in G1 undergo resection and subsequent repair by c-NHEJ. This pathway is regulated by Plk3, which after DNA damage phosphorylates CtIP on amino acids Ser327 and Thr847 in G1. Using the pRPA assay, it was demonstrated that Plk3 phosphorylates CtIP on these amino acid residues to promote resection. CtIP phosphorylation on Ser327 also mediates its interaction with Brca1 in G1, which antagonizes 53BP1 to allow resection. The results indicate that the interaction of CtIP and Brca1 is required to promote resection in G1, while depletion of 53BP1 causes hyper-resection of DSBs in G1. The primary function of Brca1 in G1 appears to be the displacement of 53BP1, similar to the mechanism in G2. Furthermore, a number of nucleases required for G1 resection were identified. Similar to the process in G2, G1 resection requires the exonuclease activities of Exo1, EXD2 and Mre11. Contrary to G2, the endonuclease activity of Mre11 is dispensable in G1, as are the activities of BLM/DNA2. Thus, it is proposed that resection in G1 might be initiated from the break end and therefore differs from the mechanism in G2 where Mre11 endonuclease function initiates bi-directional resection several hundred nucleotides away from the break end. γH2AX studies indicated that Artemis, an endonuclease which is specifically required for DBS repair during the slow component, functions downstream of the aforementioned factors. Thus, it is proposed that once resection is initiated in G1, resection intermediates have to be resolved by Artemis to complete repair. Finally, the results indicate that break ends are rejoined via a c-NHEJ process, therefore it was hypothesized that the Ku70/80 heterodimer stays bound to the DSB ends throughout the entire repair time and translocates inwards to expose DNA ends for resection while at the same time limiting the process. Immunofluorescence data support this notion by providing evidence that Ku80 co-localizes with pRPA in G1. Compared to resection in G2, which is always followed up by error-free repair via HR, resection in G1 needs to be much more limited in length. Future work will focus on the elucidation of the mechanisms restricting the extent of resection in G1.

This study was designed first to replicate previously published data which examined the effect of cadence on the rate of neuromuscular fatigue of the vastus lateralis muscle in cyclists during heavy exercise and how neuromuscular fatigue was incorporated in the selection of preferred cadence in cyclists. It was the intention of this study to expand previous work and include the examination of other lower limb musculature and detemine a global measure of neuromuscular fatigue for each cadence selected. In addition, the present study sought to assess the affect of cadence on the slow component of oxygen uptake (VO₂ SC) and attempt to establish a relationship between this slow component and a global measure of neuromuscular fatigue. Twelve cyclists performed four sessions of cycling exercise at a power output corresponding to their individual ventilatory thresholds (VT). Each criterion exercise session was performed at a different cadence, ranging from 55 to 100 RPM in 15 RPM steps. A measure of the rate of neuromuscular fatigue was calculated using both a previously published and a novel methodology. Neuromuscular fatigue was evaluated in vastus lateralis, soleus, gastrocnemius, biceps femoris, and gluteus maximus; a global representation was calculated as the sum of the rates of neuromuscular fatigue from all muscle groups. No level of neuromuscular fatigue was observed during the criterion exercise for any of the cadence conditions. There was no relationship between a global representation of neuromuscular fatigue and cadence. The VO₂ SC displayed a significant quadratic trend (p < 0.05) over the range of cadences, with a calculated minimum value at 80.8 RPM. No relationship between neuromuscular fatigue and the VO₂ SC was established, suggesting a different mechanistic basis for these two variables. These data suggested that cyclists do not use a measure of neuromuscular fatigue in the selection of preferred cadence at power outputs corresponding to VT. The cadence minimizing the VO₂ SC did not match the cyclists' preferred cadence, however did corresponded to the pedal frequency previously shown to maximize the efficiency of Type I muscle fibers.