Introduction Conclusions References Tables Figures

The interpretation of fluctuations in body weight and changes in the state of hydration requires a knowledge of the total amount of water in the organism. This investigation has been directed towards the perfection of a method for measurement of the total body water in the human subject. The increasing availability and lowered cost of both stable and radioactive isotopes has made possible study...

A snowpack’s δ2H and δ18O values evolve with snowfall, sublimation, evaporation, melt, which produces temporally variable snowpack, snowmelt, runoff isotope signals. As a snowpack ages, the relatively depleted of snow will become less sublimation internal distribution signals is altered melt moving through out snowpack. An examination for ephemeral creek water in Palouse Range northern Idaho in...

We present a new instrument, Hoxotope, for the in situ measurement of H(2)O and its heavy deuterium isotopologue (HDO) in the upper troposphere and lower stratosphere aboard the NASA WB-57. Sensitive measurements of deltaD are accomplished through the vacuum UV photolysis of water followed by laser-induced fluorescence detection of the resultant OH and OD photofragments. The photolysis laser-in...

INTRODUCTION Mechanisms of water flow across the peritoneal membrane include diffusion, convection, and reabsorption. OBJECTIVES To understand these processes more clearly we have developed a method to measure transport of water across the peritoneal membrane. METHODS An artificial gradient of deuterated water (HDO) between blood and dialysate compartments was created in five subjects who t...

Deuterium enhancement of monodeuterated species has been recognized for more than 30 years as a result of the chemical fractionation that results from the difference in zero point energies of deuterated and hydrogenated molecules. The key reaction is the deuteron exchange in the reaction between HD, the reservoir of deuterium in dark interstellar clouds, and the H3 + molecular ion, leading to t...

Hydrous pyrolysis experiments conducted on Messel shale with D2O demonstrated that a large amount of deuterium becomes incorporated into the hydrocarbons generated from the shale kerogen. In order to understand the pathway of deuterium (and protium) exchange and the role of water during hydrous pyrolysis, we conducted a series of experiments using aliphatic compounds (1,13-tetradecadiene, 1-hex...

The stable isotopes deuterium (H, D) and oxygen 18 (O) were applied in water for use as tracers in column experiments and in two field studies. Their performance was compared against uranine and was used to characterize saturated and unsaturated water movement and depths of plant water uptake. Deuterium and O are completely soluble and chemically and biologically stable. They are not subject to...

Human cholesterogenesis is measurable as the rate of Incorporation of deuterium derived from deuterium oxide (D2O) within the body water pool into plasma or erythrocyte cholesterol pools. Oral D2O equilibrates across body water, thus enabling extracellular sampling of pools (such as urine) to serve as accurate indicators of intracellular deuterium enrichments at the point of synthesis. Required...