| Reference | [1]. Eur J Appl Physiol. 2017 Jul;117(7):1277-1285. doi: 10.1007/s00421-017-3641-x. Epub 2017 May 15.<br />
Doubly labelled water assessment of energy expenditure: principle, practice, and promise.<br />
Westerterp KR(1).<br />
Author information: (1)Department of Human Biology, Maastricht University Medical Centre, PO Box 616, 6200 MD, Maastricht, The Netherlands. [email protected]. The doubly labelled water method for the assessment of energy expenditure was first published in 1955, application in humans started in 1982, and it has become the gold standard for human energy requirement under daily living conditions. The method involves enriching the body water of a subject with heavy hydrogen (2H) and heavy oxygen (18O), and then determining the difference in washout kinetics between both isotopes, being a function of carbon dioxide production. In practice, subjects get a measured amount of doubly labelled water (2H 218 O) to increase background enrichment of body water for 18O of 2000 ppm with at least 180 ppm and background enrichment of body water for 2H of 150 ppm with 120 ppm. Subsequently, the difference between the apparent turnover rates of the hydrogen and oxygen of body water is assessed from blood-, saliva-, or urine samples, collected at the start and end of the observation interval of 1-3 weeks. Samples are analyzed for 18O and 2H with isotope ratio mass spectrometry. The doubly labelled water method is the indicated method to measure energy expenditure in any environment, especially with regard to activity energy expenditure, without interference with the behavior of the subjects. Applications include the assessment of energy requirement from total energy expenditure, validation of dietary assessment methods and validation of physical activity assessment methods with doubly labelled water measured energy expenditure as reference, and studies on body mass regulation with energy expenditure as a determinant of energy balance.<br />
DOI: 10.1007/s00421-017-3641-x PMCID: PMC5486561 PMID: 28508113<br />
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[2]. Phys Chem Chem Phys. 2021 Mar 11;23(9):5467-5473. doi: 10.1039/d0cp06460b.<br />
Dielectric response of light, heavy and heavy-oxygen water: isotope effects on the hydrogen-bonding network's collective relaxation dynamics.<br />
Kutus B(1), Shalit A(2), Hamm P(2), Hunger J(1).<br />
Author information: (1)Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany. [email protected]. (2)Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.<br />
Isotopic substitutions largely affect the dielectric relaxation dynamics of hydrogen-bonded liquid water; yet, the role of the altered molecular masses and nuclear quantum effects has not been fully established. To disentangle these two effects we study the dielectric relaxation of light (H216O), heavy (D216O) and heavy-oxygen (H218O) water at temperatures ranging from 278 to 338 K. Upon 16O/18O exchange, we find that the relaxation time of the collective orientational relaxation mode of water increases by 4-5%, in quantitative agreement with the enhancement of viscosity. Despite the rotational character of dielectric relaxation, the increase is consistent with a translational mass factor. For H/D substitution, the slow-down of the relaxation time is more pronounced and also shows a strong temperature dependence. In addition to the classical mass factor, the enhancement of the relaxation time for D216O can be described by an apparent temperature shift of 7.2 K relative to H216O, which is higher than the 6.5 K shift reported for viscosity. As this shift accounts for altered zero-point energies, the comparison suggests that the underlying thermally populated states relevant to the activation of viscous flow and dielectric relaxation differ.<br />
DOI: 10.1039/d0cp06460b PMID: 33650591<br />
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[3]. PeerJ. 2014 Mar 25;2:e284. doi: 10.7717/peerj.284. eCollection 2014.<br />
Effect of (2)H and (18)O water isotopes in kinesin-1 gliding assay.<br />
Maloney A(1), Herskowitz LJ(2), Koch SJ(3).<br />
Author information: (1)College of Pharmacy, The University of Texas at Austin , Austin, TX , USA. (2)Fann Instrument Company , Houston, TX , USA. (3)College of University Libraries & Learning Sciences, The University of New Mexico , Albuquerque, NM , USA.<br />
We show for the first time the effects of heavy-hydrogen water ((2)H2O) and heavy-oxygen water (H2 (18)O) on the gliding speed of microtubules on kinesin-1 coated surfaces. Increased fractions of isotopic waters used in the motility solution decreased the gliding speed of microtubules by a maximum of 21% for heavy-hydrogen and 5% for heavy-oxygen water. We also show that gliding microtubule speed returns to its original speed after being treated with heavy-hydrogen water. We discuss possible interpretations of these results and the importance for future studies of water effects on kinesin and microtubules. We also discuss the implication for using heavy waters in biomolecular devices incorporating molecular motors.<br />
DOI: 10.7717/peerj.284 PMCID: PMC3970804 PMID: 24711961<br />
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[4]. Science. 2007 Jul 13;317(5835):231-3. doi: 10.1126/science.1142021. Epub 2007 Jun 14.<br />
Remnants of the early solar system water enriched in heavy oxygen isotopes.<br />
Sakamoto N(1), Seto Y, Itoh S, Kuramoto K, Fujino K, Nagashima K, Krot AN, Yurimoto H.<br />
Author information: (1)Department of Natural History Sciences, Hokkaido University, Sapporo 060-0810, Japan.<br />
Comment in Science. 2007 Jul 13;317(5835):211-2.<br />
Oxygen isotopic composition of our solar system is believed to have resulted from mixing of two isotopically distinct nebular reservoirs, 16O-rich and (17,18)O-rich relative to Earth. The nature and composition of the (17,18)O-rich reservoir are poorly constrained. We report an in situ discovery of a chemically and isotopically unique material distributed ubiquitously in fine-grained matrix of a primitive carbonaceous chondrite Acfer 094. This material formed by oxidation of Fe,Ni-metal and sulfides by water either in the solar nebula or on a planetesimal. Oxygen isotopic composition of this material indicates that the water was highly enriched in 17O and 18O (delta(17,18)O(SMOW) = +180 per thousand per mil), providing the first evidence for an extremely (17,18)O-rich reservoir in the early solar system.<br />
DOI: 10.1126/science.1142021 PMID: 17569827<br />
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[5]. Biofizika. 1965;10(2):349-51.<br />
[Kinetics of the inclusion of O-18 from heavy oxygen water into the molecule of violaxanthine].<br />
[Article in Russian]<br />
Sapozhnikov DI, Maslova TG, Bazhanova NV, Popova OF.<br />
PMID: 5854087
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