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The development of solutions that prevent dehydration or promote adequate re-hydration play a vital role in preventing fatigue during exercise, however, the methods commonly used to assess the hydration ability of such solutions are invasive and often assess the components of absorption separately. This paper describes using a non-invasive deuterium tracer technique that assesses gastric emptying and intestinal absorption simultaneously to evaluate the uptake of water during rest and exercise. The kinetics of absorption are further examined by mathematical modelling of the data generated. For the rest group, 0.05 g/kg of body weight of deuterium, contained in gelatine capsules, was ingested with ordinary tap water and saliva samples were collected every 5 min for one hour while the subject remained seated. The deuterium was administered as above for the exercise group but sample collection was during one hour of exercise on a treadmill at 55% of the subject's maximum heart rate. The enrichment data for each subject were mathematically modelled and the parameters obtained were compared across groups using an independent samples t-test. Compared with the rest condition, the exercise group showed delayed absorption of water as indicated by significant differences for the modelling parameters t2, t1/2, maximum absorption rate and solution absorption amount at t1. Labelling with a deuterium tracer is a good measure of the relative rate ingested fluids are absorbed by the body. Mathematical modelling of the data generates rates of maximum absorption and allows calculation of the percentage of the solution that is absorbed at any given time during the testing period. 相似文献
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Ash WW Band HR Blume HT Camporesi T Chadwick GB Coombes RW Delfino MC Fernandez E Ford WT Gettner MW Goderre GP Groom DE Heltsley BK Hurst RB Johnson JR Lau KH Lavine TL Leedy RE Lippi I Maruyama T Messner RL Moromisato JH Moss LJ Muller F Nelson HN Peruzzi I Piccolo M Prepost R Qi N Read AL Ritson DM Rosenberg LJ Shambroom WD Sleeman JC Smith JG Venuti JP von Goeler E Verdini P Wald HB Weinstein R Wiser DE Zdarko RW 《Physical review letters》1985,55(20):2118-2121
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Fernandez E Ford WT Qi N Read AL Smith JG Camporesi T De Sangro R Marini A Peruzzi I Piccolo M Ronga F Blume HT Hurst RB Venuti JP Wald HB Weinstein R Band HR Gettner MW Goderre GP Meyer OA Moromisato JH Shambroom WD Sleeman JC von Goeler E Ash WW Chadwick GB Clearwater SH Coombes RW Kaye HS Lau KH Leedy RE Lynch HL Messner RL Moss LJ Muller F Nelson HN Ritson DM Rosenberg LJ Wiser DE Zdarko RW Groom DE Lee H Delfino MC Heltsley BK Johnson JR Lavine TL Maruyama T Prepost R 《Physical review letters》1985,54(15):1620-1623
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Hsueh SY Muller D Tang J Winston R Zapalac G Swallow EC Berge JP Brenner AE Grafstrom P Jastrzembski E Lach J Marriner J Raja R Smith VJ McCliment E Newsom C Anderson EW Denisov AS Grachev VT Kulikov AV Schegelsky VA Seliverstov DM Smirnov NN Terentyev NK Tkatch II Vorobyov AA Cooper PS Razis P Teig LJ 《Physical review letters》1985,54(22):2399-2402
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The substrate and field dependencies of surface SPINOE enhancements using optical pumping and magic angle spinning NMR were monitored. Relaxation rates and enhancements were examined to gain an understanding of the parameters that determine the SPINOE enhancement. (13)C-labeled deuterated methanol was adsorbed on three different substrates (SnO(2), TiO(2), Ti/SiO(2)) with heats of adsorption for xenon ranging from 14.2 to 22.6 kJ/mol. The different heats of adsorption led to a range of xenon coverages and xenon relaxation rates. Using a simple model along with experimental values for the xenon surface polarization and cross- and self-relaxation rates, the (13)C signal enhancement could be predicted and compared with experimental enhancement values. Magnetic field dependence studies were also made by monitoring the (13)C enhancements via SPINOE from hyperpolarized xenon at fields of 0.075, 4.7, and 9.4 T. The pertinent parameters necessary to achieve maximum SPINOE enhancement are discussed. 相似文献