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1
Fawkner, Samantha Gieva. "Oxygen uptake kinetics in children." Thesis, University of Exeter, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393144.
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Baker, Mark. "Kinetics determinants of hepatic uptake." Thesis, University of Sheffield, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.699811.
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Bell, Christopher. "Control and modelling of oxygen uptake kinetics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ42497.pdf.
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Bauer, Timothy Alan. "Oxygen uptake kinetics in peripheral arterial disease." Diss., Manhattan, Kan. : Kansas State University, 2005. http://hdl.handle.net/2097/125.
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Blumoff, Sonja. "Oxygen Uptake Kinetics in Severe Intensity Exercise." Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc2539/.
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The purpose of this study was to describe mathematically the oxygen uptake kinetics during cycle ergometry, and to examine the effect of intensity on the kinetic responses within the severe domain. Sixteen volunteers performed a series of exercise tests at a range of intensities selected to elicit fatigue in ~3 to 10 min. A simple mono-exponential model effectively described the response across all intensities. There was a positive correlation between the response time and the time to fatigue, demonstrating that the maximal oxygen uptake was achieved faster at higher intensities within the severe domain. Models incorporating two components effectively described the responses only in tests lasting 8 min or more. It was concluded that there is a second, slow component in the oxygen uptake response only at the lower intensities within the severe domain.
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Wilkerson, Daryl P. "Oxygen uptake kinetics during supra-maximal intensity exercise." Thesis, Manchester Metropolitan University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424750.
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Claxton, David B. "The measurement of oxygen uptake kinetics in children." Thesis, Sheffield Hallam University, 1999. http://shura.shu.ac.uk/3152/.
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Traditional approaches to exercise testing in children may not provide the most appropriate measures of a child's physiological responses to exercise, partly because they do not reflect children's normal intermittent activity patterns. The measurement of the rate and magnitude of change of oxygen uptake to dynamic exercise, oxygen uptake kinetics (V02 KINETICS provides an alternative approach to exercise testing. A submaximal, intermittent, pseudo-random binary sequence (PRBS) exercise test to measure V02 KINETICS may provide a useful method of measuring the metabolic responses of children to exercise. Traditional methods used in the analysis of V02 KINETICS require the fitting of explicit models in order to characterise the data. These models have not however been validated for use in children. As the responses to the PRBS protocol are analysed in the frequency domain, explicit models and their physiological correlates are not required to characterise the data. Another potential problem in the measurement of V02 KINETICS in children are the small work rate changes that can be employed to stimulate the exercise response whilst constraining the test to the aerobic range. In respiratory gas measurement, breath-by-breath variability (noise) can be large in comparison to the magnitude of the metabolic response and this signal noise can obscure some characteristics of the response. The aim of the study was to develop appropriate measurement techniques to reduce the effects of breath-by-breath variability and to apply the techniques to the measurement of V02 KINETICS in children. The main experimental study compared the V02 KINETICS of children with those of adults. Ten children (3 females) in the age range 8 to 13 and twenty adults (10 females) in the age range 20 to 28 years completed a PRBS test to measure V02 KINETICS and an incremental ramp protocol on a cycle ergometer (Bosch 550 ERG) to establish V02 MAX, T VENT and delta efficiency. Breath-by-breath respiratory gas analysis was undertaken using a respiratory mass spectrometer (MGA1100). Estimates of alveolar gas exchange were made using the algorithm of Beaver et al. (1981) and a post hoc value of an effective lung volume was calculated to minimise the breath-by-breath variability. A cross-correlation technique (CC) was used to filter out the effects of anomalous (nonphysiologic) V02 responses recorded during the PRBS protocol. Subsequent Fourier analysis of the auto-correlation and CC functions provided a description of V02 KINETICS in the frequency domain in terms of amplitude ratio and phase delay over the frequency range of 2.2-8.9mHz. At each of the frequencies assessed amplitude ratio was higher in children (P<0.001) than in either of the adult groups. Phase delay was also significantly shorter in children compared to adults males (P<0.01) and adult females (P<0.001) but this effect was not identifiable at any specific frequency. Maximal oxygen uptake was not significantly different in adult males (42.5 ml"kg "min) and children (44.7 ml-kg'-min') but was lower in adult females (36.9 ml"kg "min) than adult males (P<0.01) and children (P<0.001). Ventilatory threshold (% V02 MAX) was not different between groups. Delta efficiency was significantly lower in children than adult males (P<0.05) and adult females (P<0.01). These results support the contention that there are maturational differences between adults and children in the metabolic processes involved in the utilisation of oxygen during physical activity. It has been argued, theoretically, that in adults the control of V02 KINETICS is driven by ATP demand in the skeletal muscle. As the mitochondria] capacity and the concentration of oxidative enzymes is higher in children than in adults it is likely that the controlling factor(s) for V02 KINETICS in children also relates to some aspect of peripheral metabolism. It is suggested that the PRBS protocol, with appropriate noise reduction techniques, is considered a suitable method for investigating the metabolic responses of children to dynamic exercise.
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Grant, Crystelle Kiyoko. "Influence of cardiac output on oxygen uptake kinetics /." Diss., CLICK HERE for online access, 2010. http://contentdm.lib.byu.edu/ETD/image/etd3341.pdf.
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Grant, Crystelle Kiyoko. "Influence of Cardiac Output on Oxygen Uptake Kinetics." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/1989.
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The purpose of this study was to evaluate increased cardiac output (Q) on oxygen kinetics at exercise intensities above and below the lactate threshold (LT). We hypothesized the increase in Q using head-out water immersion (HOI) while treadmill running would reduce the rate constant of the fast component and reduce the amplitude of the slow component of oxygen kinetics compared with land treadmill running. Subjects (n=10) performed two 6 min exercise bouts at a 15% below and above the LT on a land and underwater treadmill following rest. A single exponential equation [VO2(t) = VO2(b) + A1•(1-e-t/TC1] was used to evaluate VO2. The slow component at the end of exercise was estimated by subtracting (VO2(b) + A1) from the plateau. The mean LT for HOI running 1.80 ± .09 L • min-1 was significantly lower (p < 0.05) than 2.15 ± 1.03 L • min-1 while running on the land. The Q during HOI exercise below and above the LT (16.5 ± 0.6 L • min-1, 18.0 ± 1.2 L • min-1) was significantly higher (p < 0.05) than the Q during exercise below and above the LT on land (11.5 ± 0.8 L • min-1, 13.0 ± 0.7 L • min-1). During HOI exercise below LT time to reach steady-state was delayed (8 ± 2 s). Exercise above LT showed similar phase one time constants for all exercise trials. The amplitude of the slow component was not influenced by HOI. As such, the increase in during HOI exercise did not hastening uptake kinetics.
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Bailey, Stephen John. "O2 uptake kinetics as a determinant of exercise tolerance." Thesis, University of Exeter, 2011. http://hdl.handle.net/10036/3078.
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Oxygen uptake ( O2) kinetics determine the magnitude of the O2 deficit and the degree of metabolic perturbation and is considered to be an important determinant of exercise tolerance; however, there is limited empirical evidence to demonstrate that O2 kinetics is a direct determinant of exercise tolerance. The purpose of this thesis was to investigate O2 kinetics as a determinant of exercise tolerance and to consider its potential interaction with the maximum O2 ( O2max) and the W′ (the curvature constant of the hyperbolic power-duration relationship) in setting the tolerable duration of exercise. Recreationally-active adult humans volunteered to participate in the investigations presented in this thesis. Pulmonary O2 kinetics was assessed on a breath-by-breath basis and exercise tolerance was assessed by a time-to-exhaustion trial, with exhaustion taken as the inability to maintain the required cadence. A period of repeated sprint training (RST) resulted in faster phase II O2 kinetics (Pre: 29 ± 5, Post: 23 ± 5 s), a reduced O2 slow component (Pre: 0.52 ± 0.19, Post: 0.40 ± 0.17 L•min-1), an increased O2max (Pre: 3.06 ± 0.62, Post: 3.29 ± 0.77 L•min-1) and a 53% improvement in severe exercise tolerance. A reduced O2 slow component and enhanced exercise tolerance was also observed following inspiratory muscle training (Pre: 0.60 ± 0.20, Post: 0.53 ± 0.24 L•min-1; Pre: 765 ± 249, Post: 1061 ± 304 s, respectively), L-arginine (ARG) administration (Placebo: 0.76 ± 0.29 L•min-1 vs. ARG: 0.58 ± 0.23; Placebo: 562 ± 145 s vs. ARG: 707 ± 232 s, respectively) and dietary nitrate supplementation administered as nitrate-rich beetroot juice (BR) (Placebo: 0.74 ± 0.24 vs. BR: 0.57 ± 0.20 L•min-1; Placebo: 583 ± 145 s vs. BR: 675 ± 203, respectively). However, compared to a control condition without prior exercise, the completion of a prior exercise bout at 70% Δ (70% of the difference between the work rate at the gas exchange threshold [GET] and the work rate at the O2max + the work rate at the GET) with 3 minutes recovery (70-3-80) speeded overall O2 kinetics by 41% (Control: 88 ± 22 s, 70-3-80: 52 ± 13 s), but impaired exercise tolerance by 16% (Control: 437 ± 79 s, 70-3-80: 368 ± 48 s) during a subsequent exercise bout. When the recovery duration was extended to 20 minutes (70-20-80) to allow a more complete replenishment of the W′, overall kinetics was speeded to a lesser extent (by 23%; 70-20-80: 68 ± 19 s) whereas exercise performance was enhanced by 15% (70-20-80: 567 ± 125 s) compared to the control condition. In addition, the faster O2 kinetics observed when exercise was initiated with a fast start (FS; 35 ± 6 s), compared to an even start (ES; 41 ± 10 s) and slow start (SS; 55 ± 14 s) pacing strategy, allowed the achievement of O2max in a 3 minute trial and exercise performance was enhanced. Exercise performance was unaffected in a 6 minute trial with a FS, despite faster O2 kinetics, as the O2max was attained in all the variously paced trials. Therefore, the results of this thesis demonstrate that changes in exercise performance cannot be accounted for, purely, by changes in O2 kinetics. Instead, enhanced exercise performance appears to be contingent on the interaction between the factors underpinning O2 kinetics, the O2max and the W′, in support of the proposed ‘triad model’ of exercise performance.
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Leo, Tiffany. "Uptake and Release Kinetics of Sulfolane by Cattail Plants." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/47.
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Sulfolane (tetrahydrothiophene 1,1-dioxide, C4H8O2S) is a highly water-soluble, non-ionizable, organic compound used along with diisopropanolamine in the SulfinolTM process to remove hydrogen sulfide from natural gas. Sulfolane has been identified in wetland vegetation near a sour gas processing facility in Alberta, Canada, and extensive uptake of sulfolane by cattails has also been demonstrated in a laboratory environment. Consequently, it has been suggested that plants could play an important role in the natural attenuation of sulfolane in contaminated wetlands. This assumes that the sulfolane is metabolized and/or sequestered in the plant and not released back into the environment during winter dieback. To address the potential release issue, individual cattails (Typha latifolia) were grown hydroponically in 500-mL glass containers containing one of three initial sulfolane concentrations (8, 40, or 200 mg/L) for a specified duration (7 to 28 days). Half the cattails were used to quantify uptake as a function of time and exposure concentration and the other half were used to evaluate the potential release of sulfolane into the hydroponic solution. Non-exposed cattails and non-planted systems containing sulfolane served as controls. The cattails used to evaluate the potential release of sulfolane were frozen directly in their individual containers at the end of the appropriate exposure period. After being frozen for a minimum of 72 hours, the containers were thawed and the amount of sulfolane released was monitored. At the end of the 28-day uptake period, sulfolane leaf tip tissue concentrations as high as 3600, 1050, and 165 mg/kg dry weight were found for the cattails initially exposed to 200, 40, and 8 mg/L sulfolane, respectively. The percentage of sulfolane subsequently released by the cattails after the freeze-thaw treatment declined as a function of the duration exposed. The percentages of sulfolane released measured in the water after 72 hours in addition to the plant tissue extractions were 71%, 54%, 27%, and 12% for the 40 mg/L concentration at 7-, 14-, 21-, and 28-day exposure periods, respectively. Other concentrations showed the same decreasing trend for increasing exposure periods. The declining release as a function of time suggests metabolism and/or sequestration of the sulfolane within the plant. The significant uptake and limited release of sulfolane from mature plants indicate that wetland plants could play an important role in its natural attenuation.
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Pringle, Jamie S. M. "The oxygen uptake slow component in human locomotion." Thesis, Manchester Metropolitan University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268988.
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Svennerstam, Henrik. "Amino acid uptake in Arabidopsis : the transporters involved, kinetics of uptake and growth on amino acids /." Umeå : Dept. of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 2008. http://epsilon.slu.se/200850.pdf.
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Turner, Anthony Pierce. "Pulmonary oxygen uptake kinetics and exercise intensity : inferences and implications." Thesis, University of Glasgow, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407694.
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Berger, Nicolas J. A. "The effects of training and fitness on oxygen uptake kinetics." Thesis, University of Exeter, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438372.
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Sayyari, Zahan Mohammad Hassan. "Manganese efficiency and manganese uptake kinetics of different crop species." Göttingen Cuvillier, 2008. http://d-nb.info/991005724/04.
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Kilding, Andrew E. "Pulmonary oxygen uptake kinetics in middle-and long-distance runners." Thesis, Sheffield Hallam University, 2003. http://shura.shu.ac.uk/20739/.
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The overall aim of this thesis was to evaluate the importance of pulmonary oxygen uptake (VO[2]) kinetics, in the moderate-domain, in the assessment of endurance-trained runners. Accordingly, there were five objectives: 1) to quantify the reproducibility of measures of VO[2] kinetics; 2) to characterise and compare VO[2] kinetics during the on-and off-transients in middle-distance (MD) and long-distance (LD) runners; 3) to assess the relationship between VO[2] kinetics and maximal VO[2] (VO[2Max]), ventilatory threshold (V[T]) and running economy (RE); 4) to determine the relationship between VO[2] kinetics and running performance and 5) to assess whether VO[2] kinetics is a determinant of running performance. Twelve participants performed two assessments of VO[2] kinetics on separate days to determine the reproducibility. Paired t-tests showed that parameters from test 1 and test 2 did not differ (P > 0.05). Furthermore, narrow 95% limits of agreement (LOA), low measurement and method error suggested that the on- and off-transient time-constants (pion and pioff), mean response times (MRT[on] and MRT[off]) and amplitudes (A[on] and A[off]) were reproducible and could be used for the assessment of runners. Subsequently, VO[2] kinetics were compared in 10 MD and 10 LD runners. There was a tendency for pion (12.5 +/- 2.3 s vs. 14.2 +/- 3.1 s, P = 0.178) and pioff (24.1 +/- 2.3 s vs. 27.1 +/- 3.0 s, P = 0.023) to be shorter in LD than MD runners respectively, despite similar VO[2Max] (MD = 60.0 +/- 4.9 ml-kg[-1]min[-1]; LD = 59.0 +/- 6.3 ml-kg[-1]-min[-1], P = 0.689). Differences in VO[2] kinetics between MD and LD runners were attributed to approaches to training since the volume of training was greater in LD (64.0 +/- 15.7 km-wk[-1]) than MD (47.5 +/- 15.7 km-wk[-1]) runners (P = 0.047). To detail the relationships between VO[2] kinetics and other measures of aerobic function (VO[2max], V[t] and RE), 16 MD and 16 LD runners were assessed. Relationships existed between pion and VO[2max] (r = -0.72, P = 0.002), V[t] (r = -0.66, P = 0.006) and RE (r = -0.59, P = 0.016) in LD runners, but not in MD runners (P >0.05). In addition, pion was related to the volume of training in MD (r = -0.63 , P = 0.009) and LD runners (r = -0.65, P = 0.006).The importance of VO[2] kinetics for 5 km running performance was investigated in 36 endurance trained runners. Runners were categorised as high n=10), low (n=10) and combined [MD + LD (n=36)] performers according to running ability after performing a self-paced 5 km time-trial. Mean (+/-SD) speed for the 5 km time-trial was 5.2 +/-1.0 m-s[-1] (high), 4.5 +/- 0.2 m-s[-1] (low) and 4.9 +/- 0.3 m-s[-1] (combined). Measures of on- and off- transient VO[2] kinetics, VO[2max], V[t] and RE were also determined. Data were explored using bi-variate correlations, ANCOVA and multiple regression techniques. In high and low performers, V0[2] kinetic parameters were not related to running performance. In combined runners, pion, pioff, MRT[on] and MRT[off] were related (r = -0.54, P = 0.001; r = -0.36, P = 0.030; r = -0.50, P = 0.002; r = -0.63, P = 0.003) to running performance. Stepwise multiple regression models were used to identify the primary determinant(s) of 5 km running performance for each group. In high performers, VO[2Max] and RE were included in the model (r = 0.92, R = 0.85, SEE = 0.08 m-s[-1]; SEE% = 1.5). In low performers, VO[2Max] was included in the model (r = 0.76, R[2] = 0.57, SEE = 0.15 m-s[-1], SEE% = 3.3). In combined runners, V0[2Max] RE and MR[off] were included in the model (r = 0.87, R-2 = 0.75, SEE = 0.17 m-s[-1], SEE% = 3.5).Collectively, the results suggest that: 1) VO[2] kinetics can be reproducibly determined using a single visit protocol; 2) measures of VO[2] kinetics are sensitive enough to differentiate MD and LD runners; 3) relationships between VO[2] kinetics and other measures of aerobic function exist in LD runners, but not in MD runners; 4) VO[2] kinetics differ between high and low performers, but do not relate to running performance and 5) VO[2] kinetics discriminate between high and low performers but only contribute minimally to the prediction of running performance in a multiple regression model for combined MD and LD runners.
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Davie, R. J. "The uptake and transport of zinc in isolated intestinal mucosa." Thesis, Open University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234707.
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Breese, Brynmor. "Pulmonary O2 uptake kinetics and motor unit recruitment in young people." Thesis, University of Exeter, 2011. http://hdl.handle.net/10036/3263.
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The primary objective of this thesis was to examine the influence of alterations in muscle recruitment on pulmonary O2 uptake (VO2) kinetics during exercise above the gas exchange threshold (GET) in young people. In the first experimental chapter, the phase II time constant (τ) slowed over a 2-yr period in 14-16 yr old boys (25 ± 5 s vs. 30 ± 5 s, P = 0.002) and there was a greater relative VO2 slow component amplitude (Rel. A’2 (%)] during heavy-intensity exercise (9 ± 5% vs. 13 ± 4%, P = 0.036). In the second study, ‘work-to-work’ transitions yielded similar phase II VO2 kinetics during unloaded-to-moderate exercise (U→M) between 11-12 yr old boys and teenagers (19 ± 5 s vs. 22 ± 7 s, P = 0.32) but the phase II τ was significantly lengthened in the latter group at the onset of moderate-to-very heavy exercise (M→VH: 30 ± 5 s vs. 45 ± 11 s, P = 0.011). There were no differences in the phase II τ between teenagers and adult men during M→VH exercise (P = 0.46). In the third study, increasing pedal rate from 50 rev•min-1 to 115 rev•min-1 significantly (P < 0.01) lengthened the phase II τ (32 ± 5 s vs. 42 ± 11 s) and increased the relative VO2 slow component amplitude (10 ± 3% vs. 16 ± 5%) during VH cycling in untrained teenagers but the same parameters were unaltered by pedal cadence in trained junior cyclists (phase II τ: 26 ± 4 s vs. 22 ± 6 s, and Rel. A’2: 14 ± 5% vs. 17 ± 3 %, P > 0.05). The fourth study reported that a reduced relative VO2 slow component amplitude in younger boys compared to men (11 ± 4% vs. 16 ± 3%, P = 0.015) coincided with a lower percentage change in the integrated electromyogram (iEMG) of the m. vastus lateralis from minute 2 to minute 6 of exercise (ΔiEMG6-2: 7 ± 25% vs. 49 ± 48%, P = 0.030), suggesting that alterations in motor unit recruitment might be involved in restricting the O2 cost of exercise above the primary amplitude in children compared to adults. The final experimental chapter tested this hypothesis, but no statistically significant differences were reported for the relative VO2 slow component amplitude between 10-12 yr old boys and men (15 ± 7% vs. 19 ± 4%, P = 0.145). In boys, an excess VO2 temporally coincided with a significant increase in the transverse relaxation time (T2) of the m. vastus lateralis from the VO2 slow component time delay (SCtd) to minute 6 of exercise (41.5 ± 2.4 ms vs. 45.2 ± 2.3 ms, P = 0.001), thereby consistent with the notion that delayed muscle fibre activation might contribute to the development of the VO2 slow component in youth. In conclusion, this thesis has demonstrated that maturational changes in the VO2 kinetic response to heavy-intensity exercise are extended into adolescence. During intense submaximal exercise, the recruitment of higher-order (type II) muscle fibres might be principally involved in modulating VO2 kinetics as children mature but this effect is attenuated in teenage subjects engaged in regular endurance training.
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Jarvis, David R. "Multifrequent work rate forcings in the assessment of oxygen uptake kinetics." Thesis, Sheffield Hallam University, 1999. http://shura.shu.ac.uk/19870/.
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During dynamic exercise, the response of the cardiorespiratory system is structured to maintain homeostasis at the cellular level. The rate at which homeostasis is established is largely dependent on the system's structural and physiological integrity. Evidence suggests that any impairment in the functioning of the system might be reflected in a determination of oxygen uptake (VO[2]) kinetics. The kinetics of VO[2] have been quantified in response to step, impulse, ramp and sinusoidal changes in work rate (WR). An alternative approach uses a technique in which the WR is perturbed according to a pseudorandom binary signal. Pseudorandom binary sequence (PRBS) WR forcings have the advantage of being able to provide a determination of vo2 kinetics from a single test session of ~30 min duration. The assessment of VO[2]kinetics using PRBS WR forcings demands that the controlling process behaves in a linear manner. To minimise the contribution of non-linear influences, changes in work intensity must be constrained to the sub-lactate threshold domain. When examining clinical, untrained or young subjects, the necessary reduction in the upper work limit of a PRBS forcing can effect a fall in the distribution of power across the bandwidth of the sequence. If the distribution of power should fall below a critical level, then it can become difficult to elicit discernible responses from the forcing. To resolve this problem, this thesis investigated the potential for developing a multifrequent WR forcing altered to enhance identification of the underlying VO[2] response. The multifrequent WR forcing developed for use in this thesis took the form of a binary sequence. Binary transitions were determined according to a specially constructed multifrequent signal. Signal construction involved redistributing the available signal power to specific harmonics in a chosen range of frequencies. To validate estimates of VO[2] kinetics derived from the multifrequent binary sequence (MFBS) WR forcing, comparisons were made with the data obtained from an established PRBS forcing. When comparing physiological data, it is necessary to consider the amount of variability between trials. Therefore, prior to assessing the agreement between data obtained from the MFBS and PRBS methods, this thesis sought to establish the degree of variability in estimates of VO[2] kinetics derived from PRBS exercise tests. The results presented in this thesis show estimates of the mean response time (MRT) of VO[2] derived from the MFBS method to be 46.8 (4.2) s (mean (standard deviation) seconds), compared with 45.2 (5.0) s for the PRBS method. This suggests that the two methods yield comparable determinations of VO[2] kinetics. Supporting evidence is provided by the limits of agreement. These indicate that the maximum difference likely to occur between the MRT obtained from the two methods (-6.5 to +9.6 s) is less than that expected due to variability in the MRT derived from PRBS forcings (-11.6 to +8.0 s). However, the limits also reveal the poor repeatability of VO[2] response data obtained from the PRBS used in the thesis. Consequently, the use of this data to assess the validity of t the MRT derived from MFBS forcings is not recommended. In addition to poor repeatability, the possibility exists that assessments of VO[2] kinetics derived from MFBS WR forcings will also depend on the distribution of power across the harmonic content of the sequence. Therefore, whilst MFBS WR forcings may be suited to the assessment of VO[2] kinetics in subjects with a reduced tolerance to exercise, there remain doubts concerning both the validity of the response data and applicability of the method. Until these issues have been resolved, care would need to be taken when using estimates of VO[2] kinetics derived from MFBS WR forcings to determine the functional state of the cardiorespiratory system.
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Moy, Andrew Peter. "Mean blood velocity and oxygen uptake kinetics in older and younger men." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ58065.pdf.
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Baker, Jonathan. "The interaction between the oxygen uptake kinetics and the power-duration relationship." Thesis, Aberystwyth University, 2011. http://hdl.handle.net/2160/09701472-16dc-4156-b66b-53fda7cca581.
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The aim of the present thesis was to experimentally test hypotheses originally forwarded by Burnley and Jones (2007): that the kinetics interact with an individual’s capacity for substrate-level phosphorylation and maximal oxygen uptake to determine the power-duration relationship. Experiments were designed to manipulate the kinetics, the “anaerobic capacity,” and/or the maximal oxygen uptake, and determine the effect of these manipulations on the power-duration relationship. Prior high-intensity exercise was used to investigate the classic priming effect during subsequent high-intensity exercise. Both heavy- and severe-intensity exercise ‘primed’ the kinetics (i.e., increased primary amplitude, reduced the slow component trajectory and amplitude). Following 10 min recovery, prior heavy-intensity exercise increased exercise tolerance as a result of an increase in W (C: 16.0 4.8 vs. PHE: 18.7 4.8 kJ; 95% CI, 0.3, 5.2 kJ). In contrast, following the same recovery period, no difference was seen in performance or the power-duration relationship after prior severe-intensity exercise. It was considered that the accumulation of H+ ions (thereby reducing pH) during high-intensity exercise may be implicated in the fatigue process. Sodium bicarbonate ingestion was used to increase the buffering capacity of the blood. This intervention had no effect on the kinetics or , but increased CO2 production, , and blood [lactate] at exhaustion. Despite these results, no overall difference was seen in exercise tolerance between conditions; however, CP was reduced (Pl: 303 ± 48 vs. Na: 296 ± 53 W; 95% CI, 0,14 W) and W increased (Pl: 19.5 ± 8.6 vs. Na: 22.4 ± 9.2 kJ; 95% CI, -5.2, -0.7 kJ), following alkalosis. The final two studies were designed to reduce muscle O2 availability by lowering the O2 carrying capacity of the blood (Blood donation), or through a reduction in perfusion pressure (Supine exercise). Each of these interventions has similar effects on the kinetics: a reduction in the primary amplitude (and a longer time constant; supine only); no change in the slow component trajectory; and a reduction in its amplitude and . Blood donation reduced exercise tolerance, and supine exercise was performed at the same relative intensity, so no difference was seen in time to exhaustion. Each of these interventions reduced CP for blood donation and supine exercise (C: 259 ± 54; vs. BD: 246 ± 42 W; 95% CI: 2, 26W) and (UP: 275 ± 36 vs. SUP: 216 ± 13 W; 95% CI, 40, 78 W), while W was unchanged following each intervention. The experiments conducted in the current programme of research demonstrate that manipulating the kinetics, , or the parameters of the power-duration relationship have predictable effects on exercise tolerance. Hence, these data support the notion that the interaction between the kinetics, the maximal oxygen uptake, and substrate-level phosphorylation determines exercise tolerance and therefore shapes the power-duration relationship.
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DiMenna, Fred J. "The influence of muscle fibre recruitment on VO2 kinetics." Thesis, University of Exeter, 2010. http://hdl.handle.net/10036/106719.
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When O2 uptake at the lung is used to characterise the oxidative metabolic response to increased contractile activity ( O2 kinetics) in exercising muscle, the O2 profile reflects the combined influence of all involved muscle fibres. Consequently, during high-intensity exercise that mandates activation of fibres with considerable metabolic diversity (e.g., both principal fibre types), response characteristics specific to discrete segments of the recruited pool cannot be determined. The purpose of this thesis was to identify fibre-type-specific effects of conditions that might impact O2 delivery and/or motor unit recruitment patterns on O2 kinetics by using two models that increase fibre recruitment homogeneity during exercise transitions. In four experiments, subjects initiated high-intensity exercise from a moderate baseline (i.e., performed ‘work-to-work’ transitions; M→H) to target higher-order fibres, and in two experiments, subjects cycled at extremely slow and fast pedal rates to skew recruitment toward slow- and fast-twitch fibres, respectively. At mid-range contraction frequency, O2 kinetics (as indicated by the primary time constant, τp) was slower for M→H compared to unloaded-to-high-intensity transitions (U→H) (e.g., 42 v. 33 s; Ch 4) and this slowing was ~50% greater for M→H in a supine body position (decreased oxygenation; Ch 6). Slower kinetics was also present for U→H cycling at fast compared to slow pedal rates (τp, 48 v. 31 s; Ch 8). Conversely, M→H slowing relative to U→H was absent at extreme cadences (36 v. 31 s and 53 v. 48 s for slow and fast, respectively; Ch 7). After ‘priming’ (increased oxygenation), τp was reduced for U→H after fast-cadence priming only (Ch 8) and for M→H in the supine position (Ch 6), but unaffected for upright cycle and prone knee-extension M→H, for which priming reduced the O2 slow component and delayed-onset fibre activation (as indicated by iEMG; Chs 4 and 5). These results provide evidence in exercising humans that high-order fibres possess innately slow O2 kinetics and are acutely susceptible to interventions that might alter O2 delivery to muscle.
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Skiba, Philip Friere. "The kinetics of the work capacity above critical power." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/15727.
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The critical power (CP) model includes two constants: the CP and the W′ [P = W′ / t) + CP]. The W′ is the finite work capacity available above CP. Power output above CP results in depletion of the W′; complete depletion of the W′ results in exhaustion. It is possible to model the charge and discharge of the W′ during intermittent exercise using a novel integrating model (the W′BAL model), and to generate a function describing a curvilinear relationship between time constants of reconstitution of the W′ in terms of the difference between recovery power and CP (DCP) (r2 = 0.77). The depletion of the W′ as predicted by the W′BAL model during intermittent exercise is linearly related to the rise in V ̇O_2 above exercise baseline (r2 = 0.82 – 0.96). During intermittent exercise, the W′BAL model is generally robust with respect to the length of work and recovery interval, yielding a mean under-prediction of the W′BAL of only -1.6 ±1.1 kJ. The amount of W′ remaining after a period of intermittent exercise correlates with the difference between the subject’s V ̇O_2 at that time (V ̇O_2START) and V ̇O_2PEAK (DVO2) (r = 0.79, p < 0.01). Moreover, the W′BAL model also performs well in the field, permitting accurate estimation of the point at which an athlete becomes exhausted during hard training or competition (mean W′BAL at exhaustion = 0.5 ± 1.3 kJ (95% CI = 0 – 0.9 kJ). The W′BAL model meets the mathematical criteria of an excellent diagnostic test for exhaustion (area under ROC curve = 0.91). 31P magnetic resonance spectroscopy during single leg extensor exercise revealed a correlation between the recovery of the W′BAL model and recovery of creatine phosphate ([PCr]) after a bout of exhaustive single leg extensor exercise (r = 0.99, p < 0.01). The W′BAL model also accurately predicted recovery of the W′ in this setting (r = 0.97, p < 0.05). However, a complete understanding of the relationship between the depletion and recovery of [PCr] and the depletion and recovery of the W′ remains elusive. Muscle carnosine content is curvilinearly related to the rate of W′BAL recovery, with higher muscle carnosine associated with faster recovery, with implications for muscle buffering capacity and calcium handling. The W′BAL model may be recast in the form of a differential equation, permitting definition of the time constant of recovery of the W′BAL in terms of the subject’s known W′ and the DCP. This permits the scaling of the model to different muscle groups or exercise modalities. Moreover, modifications to this mathematical form may help explain some of the variability noted in the model in earlier studies, suggesting novel avenues of research. However, the present formulation of the W′BAL model is mathematically robust and represents an important addition to the scientific armamentarium, which may aid the understanding the physiology of human performance.
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Zhu, Yongguan. "Effect of potassium supply on the uptake of radiocaesium by crops." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287946.
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Wright, Wendy Janice. "Reproductive biomass and mycorrhizal colonisation in grass populations polymorphic for phosphate uptake kinetics." Thesis, University of York, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310956.
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Williams, Ruth L. "Uptake kinetics and toxicity of diazinon in the American oyster, Crassostrea virginica Gmelin." W&M ScholarWorks, 1989. https://scholarworks.wm.edu/etd/1539616906.
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Several aspects of effects of the organophosphate pesticide diazinon on the American oyster Crassostrea virginica Gmelin were investigated. Uptake of diazinon directly from water was compared with uptake of diazinon sorbed to either fine sediment or algae; the primary route of assimilation seems to be from the water. Concentrations of diazinon between 0.91 and 2.03 mg/L inhibit shell growth during 96 hours of exposure; there is a sharp threshold of effect for this response which is probably an indirect one caused by lack of food during shell closure. Acetylcholinesterase inhibition is significant in oyster heart tissue at concentrations of approximately 1 mg/L and greater. Even when inhibition is as great as 72%, however, it is not fatal. During a six-week exposure at high temperatures (22-24&\sp\circ&C), diazinon accelerated depletion of glycogen stores but had no long-term effect on total lipid reserves. Because of the disruption of the energy balance caused by the high temperature, glycogen stores in all oysters were depleted by the end of the period and little reproductive conditioning occurred. There is a suggestion of some early gametogenic activity because there was an increase in total lipid content during the first 21 days in the controls and low dose but not in the two highest doses. This increase may have resulted from conversion of some glycogen to lipid for vitellogenesis. Diazinon is rapidly accumulated and metabolized by oysters. The pesticide and its biotransformation products are quickly eliminated from the animal when exposure ends; more than 90% is removed within two days. A small fraction of the nonpolar byproducts, however, appears to be stored in the lipids. The bioconcentration factor calculated from results of an accelerated uptake test is 56; although this is low compared with that of many compounds, it is higher than that reported for diazinon in other invertebrates.
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Paggiosi, Margaret Anne. "Oxygen uptake kinetics in the frequency domain as a test for cardiorespiratory fitness." Thesis, Sheffield Hallam University, 1998. http://shura.shu.ac.uk/20158/.
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Oxygen uptake kinetics describe the characteristics of the rate of change of VO[2] in response to the onset of exercise or a change in work rate. There is a lack of knowledge concerning the use of VO[2] kinetics in the frequency domain as a test for cardiorespiratory fitness. The PRBS exercise test has been developed to study the dynamic responses of the cardiorespiratory system to random changes in submaximal work rate. This exercise test technique provides a multi-frequent assessment of VO[2] kinetics that can be expressed in terms of amplitude (ml-min[-1]W[-1]) or phase shift (degrees) over a frequency range of 0.0022 to 0.0089 Hz. The VO[2] kinetics of young women were investigated using this submaximal test during which the work rate was alternated between two levels. The upper work rate level was chosen to be below the ventilatory threshold. In the first experiment, the variability of replicate tests was investigated in a cohort of eight moderately active women (age = 22.6 +/- 0.8 years). Although there were wide limits of agreement between the two tests there was no significant difference between test 1 and test 2.In a second experiment to test the discriminant ability, oxygen uptake kinetics were compared to VO[2peak] in twenty-eight sedentary or moderately active young women (age = 22.9 +/-3.1 years). The PRBS exercise test technique was able to discriminate between a group of subjects with lower VO[2peak] (VO[2peak] = 32.3 +/- 3.3 ml-kg-1min-1) and a group of subjects with higher VO[2peak] (VO[2peak] = 41.1 +/- 3.2 ml-kg-1min-1). Differences in VO[2] kinetics occurred at frequencies of 0.0022 Hz for amplitude, and at frequencies of 0.0022 Hz to 0.0067 Hz for phase shift. Significant relationships were found to exist between VO[2peak] and VO[2] kinetics at frequencies of 0.0022Hz, 0.0044 Hz and 0.0067 Hz. The following model explained the highest proportion of the variation between VO[2peak] and VO[2] kinetics (r = - 0.72, P0.001): VO[2peak] (in ml-kg[-1]min[-1]) = 0.503(phase shift at 0.0067 Hz) (in degrees) + 72.24In a third experiment to test the sensitivity to detect change, both VO[2] kinetics and VO[2peak] were measured before, during and after an eight week endurance-type training programme completed by fifteen young women (age = 21.6 +/- 1.9 years). Thirteen young women (age = 24.3 +/-3.5 years) acted as a non-training control group. Faster VO[2] kinetics were measured at a frequency of 0.0044 Hz for amplitude and at frequencies of 0.0022Hz to 0.0067 Hz for phase shift following the training programme. Increases in VO[2peak] also occurred as a result of the exercise regimen. No changes in either VO[2] kinetics or VO[2peak] were observed in the non-training group. This study showed that the PRBS exercise test technique was sensitive to short-term endurance-type training adaptations. In conclusion, the parameters measured during the PRBS exercise test provide valuable information that can not be gained from a standard assessment of VO[2] kinetics in the time domain. It is proposed that this exercise test technique has potential as a means of assessing cardiorespiratory fitness within the area of sports science and within the clinical environment.
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McNarry, Melitta Anne. "The influence of training status on the physiological responses to exercise of young girls." Thesis, University of Exeter, 2010. http://hdl.handle.net/10036/3043.
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Exercise training represents a potent stimulus to the parameters of aerobic and anaerobic fitness in adults; whether the same is true in young girls is unclear. For some parameters, such as peak oxygen uptake, the influence of training status remains controversial whilst for other parameters, such as oxygen uptake kinetics, the influence of training status remains simply uninvestigated in young girls. Despite this lack of empirical evidence, it has been suggested for some time now that children may lack trainability and that this may be related to the presence of a maturational threshold below which significant adaptations to training cannot occur. This suggestion requires investigation, not least because the findings of some studies which appear to support this contention may in reality be a reflection of the use of an inappropriate test modality for the investigation of training status influences. The purpose of this thesis was therefore to determine the physiological trainability of girls at different stages of maturation and to investigate the interaction between training status, maturity and exercise modality. To achieve this purpose a series of 5 studies was completed, in which trained and untrained girls completed ramp incremental exercise, constant-work-rate exercise and Wingate exercise on two exercise modalities, one upper (arm crank) and one lower body (cycle). During these tests, cardiovascular, respiratory, metabolic and mechanical power parameters were assessed. In response to ramp incremental exercise, trained girls were shown to have a higher peak O2, SV and at all stages of maturity, along with an altered SV and fractional muscle oxygen extraction pattern, irrespective of exercise modality. The importance of exercise modality was evident during heavy intensity constant-work-rate exercise in pre-pubertal girls, where training status was only associated with significant influences on O2 kinetics (faster phase II time constant in trained girls) during upper body ergometry. In contrast, pubertal trained girls had faster O2 kinetics during both exercise modalities, an influence which may suggest both central and peripheral adaptations to the delivery and utilisation of oxygen. Exercise modality was also revealed to be an important factor in the demonstration of training status influences during a 30 s Wingate test, with trained girls at all stages of maturity exhibiting higher mechanical power indices during upper body ergometry only. An influence of training status was also evident in the lower fatigue index found in the trained girls at all stages of maturity during both modalities, but no influence was found in the oxidative contribution to the Wingate test. None of these studies revealed an influence of maturity status in determining the magnitude of training status effects. Overall, the 5 studies encompassed within this thesis demonstrate that children are trainable and that this is not moderated by maturity.
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Dascombe, Benjamin James, and b. dascombe@cqu edu au. "Pulmonary Oxygen Uptake and Muscle Oxygenation Responses to Exercise in Well-Trained Young and Middle-Aged Cyclists." Central Queensland University. Department of Health and Human Performance, 2007. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20070719.105750.
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This thesis details four consecutive research investigations which were designed to examine the effect of age on the pulmonary oxygen uptake (VO2)and muscle oxygenation (mOxy) responses to exercise in well-trained cyclists. (Abridged)
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Sirna, Karen Margaret. "The effect of body position on oxygen uptake and heart rate kinetics in older people." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0007/MQ32509.pdf.
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Burnley, Mark. "Effects of prior exercise on the on-transient oxygen uptake kinetics of constant-load exercise." Thesis, University of Brighton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392874.
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Wells, Carl M. "Relationship between pulmonary oxygen uptake kinetics and high-intensity running performance in professional soccer players." Thesis, Sheffield Hallam University, 2005. http://shura.shu.ac.uk/20676/.
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The overall aim of this thesis was to identify whether oxygen uptake (VO2) kinetics are a determining factor in the performance of soccer-specific high-intensity exercise. To achieve this aim there were five objectives: 1) to design a protocol for the assessment of VO2 kinetics at the onset and cessation of moderate- and heavy-intensity treadmill running; 2) to assess the reproducibility of VO2 kinetics measured during such a protocol; 3) to quantify the characteristics of VO2 kinetics during the onset and cessation of moderate- and heavy-intensity running; 4) to identify if VO2 kinetics discriminate between elite and non-elite soccer players and 5) to identify the physiological processes (VO2 kinetics, VO2 max, GET, anaerobic capacity) that determine soccer-specific high-intensity running capacity. To establish the day-to-day variability in aerobic markers of moderate- (80%GET) and heavy-(50%Delta) intensity exercise domains, the pulmonary gas exchange of nine participants was measured during an incremental treadmill test to exhaustion on two occasions. Narrow 95% limits of agreement (LOA) and low coefficients of variation (CV) indicated that such markers of intensity were reproducible. Based on these findings, eight participants performed a repeated exercise transition treadmill protocol (six moderate (80%GET) and two heavy (50%A) transitions) on two occasions. Two-way analysis of variance with repeated measures (ANOVA) revealed the phase II time constant (tau[1]) to be invariant across intensity domains for both exercise transients (tau[1]on, moderate 23.2 +/- 2.9 s vs. heavy 23.7 +/-3.1 s; tau[1off] moderate 27.4 +/- 3.5 s vs. heavy 27.1 +/- 2.4 s), while both phase II and III tau were quicker during the onset than cessation of exercise (phase III, tau[2on] 177.5 +/- 43.9 s vs. tau[2off] 396.1 +/- 52.3). The 95% LOA and CV for phase II parameters were small for both intensities and transients of exercise. Conversely, broad 95% LOA were identified for all the phase III parameters. To address this problem, the treadmill protocol was modified to include four very heavy-intensity exercise transients (80%?) to improve the signal-to-noise ratio of the phase III response. Analysis of test-retest data obtained from ten participants revealed that although the CV and 95% LOA for the phase III parameters were improved, they were still larger than for phase II parameters. Using the very-heavy intensity treadmill protocol, a relationship (bivariate correlation) was found between r1on and soccer-specific high-intensity running capacity, both for professional (Pro, n = 18) (r = -0.71; P =0.013) and amateur (Am, n = 18) (r = -0.69; P = 0.014) soccer players. However, the role VO2 kinetics plays in such exercise appears to be limited, as a mixed design two-way ANOVA revealed that the Pro players ran further in a test of soccer-specific fitness (Pro 966 +/- 153 m vs. Am 840 +/- 156 m) despite the VO2 kinetic profiles of the two groups being indistinguishable (tau[1on], Pro 24.5 +/- 3.2 s vs. Am 24.7 +/- 1.8 s; tau[1off], Pro 28.7 +/- 2.8 s vs. Am 29.3 +/-3.5 s). To identify which physiological processes did determine soccer-specific high-intensity running capacity among elite players, a longitudinal study was conducted with 16 Pro soccer players (8 = controls, 8 = training), whose soccer specific fitness, aerobic (VO[2] max, VO[2] kinetics) and anaerobic profiles (anaerobic capacity) were assessed before and after a six week high-intensity training intervention. A two-way ANOVA mixed design revealed soccer-specific fitness (P=0.015) and anaerobic capacity (P = 0.021) were the only measures that increased among the training group following the intervention. The change between the two measures was also correlated (r = 0.89; P = 0.012). It is plausible that due to the sporadic nature and high-intensity of the running performed in soccer, VO2kinetics are not a determinant of performance, and above a certain threshold of aerobic fitness, it is the capacity for anaerobic energy production that is crucial for the performance of soccer-specific high-intensity running.
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Fitzsimons, Claire Frances. "Oxygen uptake kinetics at the onset of exercise and cardiorespiratory fitness in frail elderly people." Thesis, University of Edinburgh, 2006. http://hdl.handle.net/1842/24572.
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Methods: VO2 and walking speed were measured during 3 minutes of comfortable self-paced walking in young (Y) (N=17, median age 23 (20-29) years) and healthy elderly (HE) (N=15; median age 80 (76-87) years) volunteers and groups of patients recovering from a hip fracture (HF) (N=8; median age 81 (72-91) years) or stroke (ST) (N=66; median age 74 (49-87) years). Results: Feasibility. On 214/277 study visits individuals completed 3 walks of 3 minutes (77%). Participants maintained a constant walking speed of moderate intensity and achieved steady state VO2 conditions within 3 minutes on 127/214 visits. 114/127 visits (41% of 277) were adequately described using a monoexponential model (82% Y; 44% HE; 53% HF; 32% ST). Validity: A group comparison of MRT demonstrated content validity (Y 20s; HE 37s; HF 52s; ST 42s, mean values, visit 1). Criterion-related concurrent validity (MRT versus VO2 max, in Y and HE) and predictive validity of MRT were not demonstrated. Reproducibility: The Standard Error of Measurement (SEM) of the MRT was 4.9s in the Y group, 4.4s in the HE group and 7.0s for the HF group. Limits of agreement of MRT for the HF group were -23 to 30s. Training intervention: Poor tolerance of the study methodology in the frailer stroke patients compromised evaluation of the training intervention. A before and after training comparison of MRT was possible in 4 stroke patients. A training related reduction in MRT (49s to 35s (mean values, N=4)) was evident. Conclusion: The inability of frailer study participants to achieve feasibility criteria and inconclusive validity questions the applicability of this measure to those for whom it is intended – very frail, older people.
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Hu, Qing. "Migration and plant uptake of radionuclides in laboratory soil columns and field lysimeter with contaminated water tables." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287371.
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Bowen, Mary. "Sex Differences in the Oxygen Uptake Kinetic Response to Moderate Intensity Exercise in Obese Adolescents." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/332.
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The oxygen uptake (VO2) kinetic response to exercise provides insight into aerobic performance and the efficiency of the body to maintain oxygen demand during the initiation of exercise. Previous research in normal weight children reports insignificant differences in gender VO2 on-kinetic responses to moderate exercise. No study has evaluated the impact obesity may have on gender VO2 on-kinetics. PURPOSE: To determine if sex differences exist in the VO2 kinetic response to moderate exercise in obese adolescents. METHODS: Male (n=16) and female (n=39) adolescents completed a graded exercise test to exhaustion on a treadmill. Data from initial 4-min treadmill walking was used to determine a time constant. RESULTS: The time constant was significantly different (P=0.009) between obese male and female adolescents (15.42±7.31 s vs. 22.03±8.56 s, respectively). CONCLUSION: Sex differences exist in VO2 on-kinetics during moderate exercise in obese adolescents indicating an enhanced potential for males to deliver and/or utilize oxygen.
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Oyedepo, Aderonke Caroline. "Human skeletal uptake of natural alpha radioactivity from '2'1'0Pb-supported '2'1'0Po." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297922.
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Ritchie, James William Alexander. "Molecular mechanisms of thyroid hormone transport : the role of amino acid transporters." Thesis, University of Dundee, 2000. https://discovery.dundee.ac.uk/en/studentTheses/4a30ffbf-102f-484f-be68-61d133333050.
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Thyroid hormones (TH) exert their multitude of effects on body development, growth and metabolism largely via transcriptional regulatory pathways. TH-induced transcription is controlled by receptors present in the cell nucleus, therefore extracellular TH must first cross the plasma membrane to gain entry into the cell. The exact mechanisms of TH transport across the plasma membrane are only beginning to be clarified, but it is likely that transport may be an important control step for the effects of TH on transcription. Members of the recently cloned organic anion transporting polypeptide (OATP) family have been shown to transport TH. Inhibitor studies indicate that both the aromatic amino acid System T-type transporter, and the broad scope neutral amino acid transporter System L are mediators of TH uptake into various cell types. However cloned amino acid transporters have not been studied to demonstrate directly whether they can accept TH as substrates.
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Ummadi, Madhavi. "Uptake, Absorption, and Adsorption Kinetics of Ferrous and Ferric Iron in Iron-replete and Iron-deficient Rats." DigitalCommons@USU, 1994. https://digitalcommons.usu.edu/etd/5409.
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Various concentrations of ferrous and ferric iron solutions were held at room temperature for 60 min before they were assayed for ferrous iron, which may be unstable due to oxidation. The ferrous and ferric solutions (in pH 2 HCl) were maintained as such for 60 min without the use of chelators. There was no significant oxidation of ferrous iron. Also, four different levels of each ferrous and ferric iron were injected into proximal duodenal loops of rat intestine and uptake was determined at four different time intervals. Two iron-replete rats were assigned to each of the treatments. The in situ experiments showed that iron was taken up rapidly from pH 2.0 solutions of ferrous and ferric iron. Maximum amount of iron was taken up in the first 10 min. Uptake of ferrous iron was significantly greater (p < 0.05) than uptake of ferric iron, and there were significant differences in total uptake among the four iron levels used.
Uptake, absorption, and adsorption kinetics of both ferrous and ferric iron were determined in situ for both iron-replete and iron-deficient rats. Deficiency caused greater uptake and absorption, confirming a biological adaptation of these processes. Both uptake and absorption were greater for ferrous than for ferric iron and were possibly taken up by different pathways or by a ferrous-ferric pathway with preference for ferrous. Uptake and absorption kinetics were biphasic for both ferrous and ferric iron. The first phase demonstrated saturation kinetics and was followed by a nonsaturable phase at higher concentrations of luminal iron. Iron deficiency altered the uptake and absorption kinetics of ferrous and ferric iron, but not always in a similar manner, suggesting that ferrous and ferric iron were each taken up by a separate pathway. Indications were that enhanced absorption during deficiency was largely due to adaptation of ferric uptake. Iron adsorption was directly proportional to luminal iron concentration, but it was greater for ferric than for ferrous, possibly due to charge interactions. Iron deficiency caused increased adsorption of both ferrous and ferric iron, supporting the notion that adsorption acts to maintain iron in a form available for uptake.
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Chaiprapat, Sumate. "Modeling Nutrient Uptake Process and Growth Kinetics of Duckweed Spirodela punctata 7776 for Nutrient Recovery from Swine Wastewater." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-08132002-090507/.
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Use of plants for swine waste management involves the removal of nutrients from the swine wastewater by the plants and the utilization of the plant biomass for other useful purposes such as feed supplement and soil amendment. Duckweed has gained much interest for this purpose in the past decades because of its high growth rate and high protein content. The goal of this research was to study the characteristics of duckweed growth and nutrient uptake from swine wastewater in order to improve the efficiency of duckweed nutrient recovery. In the first part of this research, nutrient distribution and transport in a quiescent duckweed-covered pond containing swine lagoon liquid were investigated and described mathematically. A superior duckweed strain for total protein production in swine wastewater Spirodela punctata 7776 was used as a subject of the study. Diffusive transport of ammonium was shown to be a limiting process in nitrogen removal by duckweed plants in static ponds. In addition, a pH profile developed along the depth of the pond, creating an additional barrier to ammonia volatilization from the pond covered with a duckweed mat. In the second part of the research, growth and nutrient uptake characteristics of Spirodela punctata 7776 in artificial swine medium were examined in sterile batch cultures. Growth of Spirodela punctata 7776 corresponded to the amount of nitrogen storage in its biomass rather than the nutrient concentration in the growth medium. The relationship followed Monod-like kinetics with a maximum specific growth rate of 0.2381 g/g/d. Reduction in the specific growth rate of Spirodela punctata 7776 was observed in the culture with higher crop density, which signified the adverse effects of surface crowding. A mathematical expression to represent the effects of crop density (mass per unit area) on specific growth rate was developed, which can be used in optimization of crop density management in duckweed nutrient recovery systems.
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Ucisik, Ahmed Suheyl. "Uptake of chemicals and metabolism kinetics related to toxic effects and consideration of phytoremediation as a remediation option." Kgs. Lyngby, 2007. http://www.er.dtu.dk/publications/fulltext/2007/MR2007-044.pdf.
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Covino, Timothy Patrick. "The role of stream network nutrient uptake kinetics and groundwater exchange in modifying the timing, magnitude, and form of watershed export." Diss., Montana State University, 2012. http://etd.lib.montana.edu/etd/2012/covino/CovinoT0512.pdf.
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In this PhD dissertation research we sought to elucidate stream network biological and physical influences on hydrological and biogeochemical signatures observed along stream networks and at watershed outlets. Our research indicates that stream nutrient uptake and groundwater exchange processes can modify inputs from terrestrial sources and influence the timing and signature of watershed fluxes. We determined that stream nutrient uptake followed Michaelis-Menten kinetics across a broad range of systems and that land use / land cover change can alter stream nutrient uptake magnitudes. Additionally, we found that watershed structure and network geometry exerted strong controls over sourcewater contributions and streamwater compositions along stream networks and at watershed outlets. Combined, this PhD research suggests that uptake kinetics and hydrologic turnover exert strong controls over streamwater composition and sourcewater contributions, and that physical and biological contributions to total nutrient retention and the dynamic and concentration dependent nature of biological uptake combine to control solute and nutrient signatures. We suggest accurate assessment of total retention across stream reaches and stream networks requires quantification of physical retention and the concentration dependent nature of biological uptake, understanding necessary to help mitigate the potentially deleterious influences elevated nutrient export can have on downstream ecosystems. 'Co-authored by Brian L. McGlynn, Rebecca A. McNamara, John Mallard, Michelle Baker, Sheng Ye, Murugesu Sivapalan, Nandita B. Basu, Hong-Yi Li, Shao-Wen Wang, Sopan Patil, Aaron Packman, Jennifer Drummond, Robert Payn, Rina Schumer, Antoine Aubeneau, and Doris Leong.'
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Lee, Patrick. "The effect of calcium-channel blockade on oxygen uptake kinetics during moderate and heavy intensity exercise in young and old adults." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ58052.pdf.
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Scolaro, Sara. "Effects of humidity and fatty acid surfactants on the uptake of NO2 to NaCl : combined study of kinetics and surface analysis." Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10098/document.
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Des études cinétiques et des analyses de surface ont été effectuées sur la réaction multiphasique entre le gaz NO2 et des cristaux de NaCl en présence de molécules tensio-actives sous air humide. Ces études de laboratoire contribuent à la validation de processus de chimie atmosphérique suggérés par des campagnes de mesure sur des aérosols d’origine marine. Les vents provoquant des vagues à la surface des océans propulsent de nombreuses gouttelettes d’eau de mer dans la troposphère où elles se déshydratent partiellement et forment l’aérosol marin, constitué de particules de taille micrométrique comportant du NaCl et de nombreux composés mineurs dont des acides gras (stéarique, oléique). Les concentrations en particules peuvent dépasser 20 µg/m3 dans l’air des zones côtières. Des quantités énormes d’oxydes d’azote (NO, NO2) sont émises actuellement par les transports et le chauffage et leur concentrations peuvent dépasser 100 µg/m3 dans les zones fortement antropisées. Le passage de masses d’air d’origine marine dans des zones fortement urbanisées a des impacts négatifs sur la qualité des eaux continentales par des pluies chargées en nitrates et sur la qualité de l’air par des dégagements de gaz chlorés. La cinétique de la réaction montre que la capture de NO2 par NaCl est favorisée a des fortes humidités. Par contre un revêtement d’acides gras réduit peu la production de NaNO3 et l’émission de NOCl. Les études de surfaces par microimagerie Raman polarisée et microscopie à force atomique mettent en évidence des processus de précipitation et de migration de surface dans la production de nanocristaux de NaNO3 et le faible rôle protecteur des molécules tensio-activesIn this laboratory work we studied an important atmospheric process typical of polluted costal regions: the heterogeneous reaction of a gaseous pollutant of mainly anthropogenic origin, NO2, on NaCl(100), taken as a surrogate for marine aerosol. Evidence of the presence of a native organic coating on field-collected marine aerosol particles inspired us to investigate the effect of insoluble fatty acids on the heterogeneous removal reaction of NOx in the marine boundary layer. The originality of this work consists in coupling reactivity studies with high spatial resolution surface analysis. The surface is followed, before and after reaction, via Raman micro-spectrometry and AFM techniques. Significant modifications in the morphology and orientation of the formed NaNO3 crystals on the surface are found as a function of humidity during the reaction. A thin organic coating on the salt surface is prepared and characterized. The reactivity of the coated/uncoated salt is measured in a static reactor where the gaseous phase composition can be monitored by FTIR spectrometry in different humidities (RH=0-80%). From NO2 and ClNO kinetics we can independently estimate both the uptake and the reaction probability coefficients. The presence of a palmitic or oleic acid coating slightly hinders the reactivity, especially in some humidities. By coupling all experimental information to a simple reactivity model which fits the experimental data well, we can conclude that the NO2/NaCl reaction directly releases a precursor of active chlorine atoms (ClNO) into the atmosphere, even at high humidities
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Corn, Sarah D. "Effects of N-Acetylcysteine on fatigue, critical power, and muscle energy stores." Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1632.
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Zimmermann, Kristen Ann. "Intracellular Transport in Cancer Treatments: Carbon Nanohorns Conjugated to Quantum Dots and Chemotherapeutic Agents." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/72986.
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Cancer therapies are often limited by bulk and cellular barriers to transport. Nanoparticle or chemotherapeutic compound intracellular transport has implications in understanding therapeutic effect and toxicity. The scope of this thesis was to study the intracellular transport of carbon nanohorns and to improve the efficacy of various chemotherapeutic agents through increased intracellular transport.
In the first study, fluorescent probes (quantum dots) were conjugated to carbon nanohorns to facilitate the optical visualization of the nanohorns. These hybrid particles were characterized with transmission electron microscopy, electron dispersive spectroscopy and UV-VIS/FL spectroscopy. Their cellular uptake kinetics, uptake efficiencies, and intracellular distribution were determined in three malignant cell lines (breast – MDA-MB-231, bladder – AY-27, and brain – U87-MG) using flow cytometry and confocal microscopy. Intracellular distribution did not vary greatly between cell lines; however, the uptake kinetics and efficiencies were highly dependent on cell morphology. In the second study, the efficacy of various chemotherapeutic agents (i.e., doxorubicin, cisplatin, and carboplatin) was evaluated in AY-27 rat bladder transitional cell carcinoma cells. In the future, severe hyperthermia and chemothermotherapy (chemotherapy + hyperthermia) will also be evaluated. Doxorubicin and cisplatin compounds were more toxic compared to carboplatin. Hyperthermia has previously shown to increase the cellular uptake of chemotherapeutic agents; therefore, chemothermotherapy is expected to have synergistic effects on cell death. This work can then be translated to carbon nanohorn-based laser heating to generate thermal energy in a local region for delivery of high concentrations of chemotherapeutic agents. Although these two concepts are small pieces of the overall scope of nanoparticle-based therapies, they are fundamental to the advancement of such therapies.Master of Science
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Wilson, Timothy Dale. "The effects of prior heavy intensity exercise on oxygen uptake kinetics and aortic mean blood velocity during moderate intensity exercise in older adults." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0004/MQ42225.pdf.
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Drescher, Uwe [Verfasser]. "Analysis of temporal and distortive dissociations between muscle and pulmonary oxygen uptake kinetics during dynamic exercise : theoretical considerations and practical applications / Uwe Drescher." Köln : Zentralbibliothek der Deutschen Sporthochschule, 2018. http://d-nb.info/1212471652/34.
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Baranauskienė, Neringa. "Skirtingos lyties asmenų vegetacinių sistemų funkcijos rodiklių kaitos pastovaus intensyvumo krūvio metu ypatumai po ekscentrinio-koncentrinio prieškrūvio." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2007. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2007~D_20070816_145155-19426.
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Tyrimo tikslas – nustatyti skirtingos lyties asmenų vegetacinių sistemų funkcijos rodiklių kaitos ypatumus pastovaus intensyvumo krūvio metu po ekscentrinio-koncentrinio prieškrūvio.
Tyrimo uždaviniai: 1. Nustatyti ekscentrinio-koncentrinio prieškrūvio poveikį vegetacinių sistemų rodiklių kaitai atliekant vidutinio ir didelio intensyvumo aerobinį darbą. 2. Palyginti ekscentrinio-koncentrinio prieškrūvio poveikį vegetacinių sistemų rodiklių kaitai ir sukelto vėluojančio skausmo raumenyse poveikį atliekant įvairaus intensyvumo aerobinį darbą tarp skirtingos lyties asmenų.
Tyrimo metodai ir organizavimas.Tyrimuose sutiko dalyvauti 18-ka tiriamųjų, merginos (n=10), kurių amžius buvo 20,9 (0,5) m. ir vaikinai (n=8), jų amžius – 20,8 (1,9) m. Siekiant nustatyti aerobinį pajėgumą tiriamieji po veloergometru „Ergoline –800“ (Vokietija) atliko nepertraukiamą nuosekliai kas 5 s didinamą krūv�� (NDK). Mynimo dažnumas buvo 70 k./min. Pirmas 3 minutes krūvis buvo 20 W, toliau krūvis buvo didinamas po 2 W iki nuovargio, t.y. tol, kol tiriamasis galėjo išlaikyti pastovų mynimo dažnumą. Pagal deguonies suvartojimo per paskutines krūvio 15 s priklausomybę nuo darbo galingumo buvo nustatomas maksimalus deguonies suvartojimas ( max). Pirmas ir antras ventiliaciniai slenksčiai (VeS1, VeS2) buvo nustatomi pagal Ve, o taip pat Ve/ ir Ve/VCO2 ekvivalentų priklausomybę nuo darbo galingumo. Po nepertraukiamo nuosekliai didinamo krūvio tiriamieji atliko individualizuotą vidutinio intensyvumo aerobinį... [toliau žr. visą tekstą]The aim of this study was to ascertain the sex differences in the influence of prior eccentric-concentric load on the kinetics of cardiorespiratory parameters during constant intensity exercise. The tasks set were as follows: 1. To estimate the influence of prior eccentric-concentric load on the changes of cardiorespiratory parameters during moderate and high intensity exercises. 2. To compare sex differences in the influence of prior eccentric-concentric load on the changes of cardiorespiratory parameters and effect of delayed onset muscle soreness during various intensity exercises. Materials and methods. The subjects were ten healthy female 20,9 (0,5) years and eight healthy male 20,8 (1,9) years volunteered to participate in this study. The first test was used to measure their maximal oxygen uptake during an incremental exercise (3 min was 20 W and then 2 W/ 5s at 70 rev/min) to exhaustion on the cycle ergometer Ergoline-800 (Germany). Depending of in last 15 s on load output was determinate max. Both first and second ventilatory thresholds (VeS1, VeS2) were determinate by pulmonary ventilation (Ve) and depending of Ve/ and Ve/VCO2 equivalents on load output. Thereafter, the moderate intensity exercise (MI) corresponding to 80% of VeS1, and high intensity exercise (HI) corresponding to 50% of VeS2 and VeS1 inequality was determined individualized load for each subject. Cycling rapid was 70 rev./min. During whole tests of each respiratory period were recorded indices as... [to full text]
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MALAGRINO, WALDIR. "Bioacumulacao e eliminacao de mercurio (sup(203)Hg) no mexilhao (Perna perna, Linne, 1758) .Modelo cinetico para avaliar o risco de ingestao no homem." reponame:Repositório Institucional do IPEN, 2003. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11095.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP