Photoluminescence investigation of InGaAs-InP quantum wells

Moroni, D.; André, J.P.; Menu, E. P.; Gentric, P.; Patillon, J. N.

doi:10.1063/1.339541

Cited by 84 publications

(8 citation statements)

References 22 publications

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“…No measures of habitual physical activity were taken post-intervention; therefore, it is not presently possible to account for the effect of any potential changes in habitual physical activity and their influence of the results observed. Finally, it is suggested that several repeat transitions are needed for reliable characterisation of V O 2 kinetic response (Lamarra et al 1987). Indeed, the lower phase II amplitude observed in the obese children following the intervention may be an artefact of the modelling process consequent to the use of a single transition or to the onset of the slow component being determined subjectively.…”

Section: Discussionmentioning

confidence: 99%

The influence of a six-week, high-intensity games intervention on the pulmonary oxygen uptake kinetics in prepubertal obese and normal-weight children

McNarry

Lambrick

Westrupp

et al. 2015

Appl. Physiol. Nutr. Metab.

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The pulmonary oxygen uptake response is deleteriously influenced by obesity in prepubertal children, as evidenced by a slower phase II response. To date, no studies have investigated the ability of an exercise intervention to ameliorate this. The objective of the study was to investigate the influence of a 6-week, high-intensity, games-orientated intervention on the oxygen uptake kinetic response of prepubertal obese and normal-weight children during heavy-intensity exercise. Thirteen normal-weight and 15 obese children participated in a twice-weekly exercise intervention involving repeated bouts of 6-min high-intensity, games-orientated exercises followed by 2 min of recovery. Sixteen normal-weight and 11 obese children served as a control group. At baseline and post-intervention, each participant completed a graded-exercise test to volitional exhaustion and constant work-rate, heavy-intensity exercise. Post-intervention, obese children demonstrated a reduced phase II τ (pre-intervention: 30 ± 8 cf. post-intervention: 24 ± 7 s), mean response time (pre-intervention: 50 ± 10 cf. post-intervention: 38 ± 9 s) and phase II amplitude (pre-intervention: 1.51 ± 0.30 cf. post-intervention: 1.34 ± 0.27 L·min(-1)). No changes were evident in the normal-weight children. In conclusion, the present findings demonstrate that a 6-week, high-intensity intervention can have a significant positive impact on the dynamic oxygen uptake response of obese prepubertal children.

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Section: Discussionmentioning

confidence: 99%

The influence of a six-week, high-intensity games intervention on the pulmonary oxygen uptake kinetics in prepubertal obese and normal-weight children

McNarry

Lambrick

Westrupp

et al. 2015

Appl. Physiol. Nutr. Metab.

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show abstract

“…This has a similar effect to previous methods for modeling oxygen uptake using exponential functions that highlight the underlying kinetics of the breath-by-breath fluctuations (Jones & Poole 2005). There is no physiological explanation to indicate that these fluctuations are directly related to the contractions of the individual muscles, and therefore evident in the EMG signal, since they represent ‘white noise’ and are not important to the overall gas exchange kinetics (Lamarra et al 1987) and metabolic estimations. This implies that the fundamental information about metabolic power is contained in the EMG signal and the transfer function (Eq.…”

Section: Discussionmentioning

confidence: 99%

Estimating changes in metabolic power from EMG

Blake

Wakeling

2013

SpringerPlus

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Metabolic rates can increase 21 times above resting levels during cycling with the majority attributed to muscular contractions. Metabolic estimates attained through gas exchange parameters are limited by the respiration rate and time delay with respect to these contractions. In contrast surface electromyography (EMG) contains instantaneous muscle contraction information at higher temporal resolutions. An adequate metabolic power-EMG relationship has not been established to use EMG as a metabolic estimate during dynamic activities. The purpose of this study was to establish a metabolic power-EMG relationship during non steady-state conditions. Participants cycled at workloads between 25 and 90% O2max while EMG and gas exchange were monitored. The EMG was resolved into intensities and total EMG intensity was calculated as the sum of intensities across all muscles for each pedal cycle. Metabolic power was estimated from gas exchange parameters and the mean total EMG intensity between breaths was calculated and used as breath-by-breath values. Comparisons were made between breath-by-breath resolutions of metabolic power and total EMG intensity. Different weighting coefficients were also applied to the EMG for each muscle to analyze the effects of different muscle weightings on metabolic power estimations. There was a significant correlation (r = 0.91) between estimates of metabolic power from EMG and gas exchange. Muscle weighting had a significant effect on metabolic power determination with the highest and lowest correlated estimates having the largest weightings on muscles proximal and distal to the knee respectively. This study demonstrates that EMG contains important information about the metabolic costs of muscle contractions and provides good predictions of metabolic changes during non steady-state conditions. Also, the importance of each muscle is workload dependent with inappropriate weightings reducing metabolic estimations. These findings have implications for future EMG applications as they provide more immediate, higher temporal resolution predictions of changes in metabolic power.

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“…In other cases, occasional outliers or missing HR data were replaced by averaging surrounding valid values. Breath-by-breath data were further smoothed using a 7-point centred moving average (Moroni et al 1987) and averaged at 30-s intervals using the manufacturer's software program provided for each apparatus. The final data-set included 41 measurements from 7 tree planters and 34 brushcutters.…”

Section: Data Preparation and Processingmentioning

confidence: 99%

Prediction of work metabolism from heart rate measurements in forest work: some practical methodological issues

et al. 2015

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Individual heart rate (HR) to workload relationships were determined using 93 submaximal step-tests administered to 26 healthy participants attending physical activities in a university training centre (laboratory study) and 41 experienced forest workers (field study). Predicted maximum aerobic capacity (MAC) was compared to measured MAC from a maximal treadmill test (laboratory study) to test the effect of two age-predicted maximum HR Equations (220-age and 207-0.7 × age) and two clothing insulation levels (0.4 and 0.91 clo) during the step-test. Work metabolism (WM) estimated from forest work HR was compared against concurrent work V̇O2 measurements while taking into account the HR thermal component. Results show that MAC and WM can be accurately predicted from work HR measurements and simple regression models developed in this study (1% group mean prediction bias and up to 25% expected prediction bias for a single individual). Clothing insulation had no impact on predicted MAC nor age-predicted maximum HR equations. Practitioner summary: This study sheds light on four practical methodological issues faced by practitioners regarding the use of HR methodology to assess WM in actual work environments. More specifically, the effect of wearing work clothes and the use of two different maximum HR prediction equations on the ability of a submaximal step-test to assess MAC are examined, as well as the accuracy of using an individual's step-test HR to workload relationship to predict WM from HR data collected during actual work in the presence of thermal stress.

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Photoluminescence investigation of InGaAs-InP quantum wells

Cited by 84 publications

References 22 publications

The influence of a six-week, high-intensity games intervention on the pulmonary oxygen uptake kinetics in prepubertal obese and normal-weight children

The influence of a six-week, high-intensity games intervention on the pulmonary oxygen uptake kinetics in prepubertal obese and normal-weight children

Estimating changes in metabolic power from EMG

Prediction of work metabolism from heart rate measurements in forest work: some practical methodological issues

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