Abstract The possibility of estimating groundwater inflow to irrigation drains in Minia, Egypt, using stable isotopes has been explored. The evaporation pan technique described here makes use of small variations in the concentration of naturally occurring stable isotopes (oxygen-18 and deuterium) in irrigation-fed groundwater and surface water as well as agricultural drainage water. The agreeme...

Stable isotope labeling (SIL) still has not been used very much in pediatric and perinatal clinical pharmacology. However, this method has numerous advantages. It allows one to determine the concentration of drugs with great sensitivity, thereby allowing quantification in small amounts of biologic samples. It also allows quantification with great specificity, eliminating interference by drug me...

The reaction of molecular oxygen with a Pd(II)-hydride species to form a Pd(II)-hydroperoxide represents one of the proposed catalyst reoxidation pathways in Pd-catalyzed aerobic oxidation reactions, but well-defined examples of this reaction were discovered only recently. Here, we present a mechanistic study of the reaction of O2 with trans-(IMes) 2Pd(H)(OBz), 1 (IMes = 1,3-dimesitylimidazol-2...

Using the Effelsberg 100-m telescope, sensitive measurements of the H2O megamaser in NGC 3079 are presented. During 2000 – 2001, 'high velocity' features are seen that are red-shifted up to 225 km s −1 with respect to the systemic velocity of the galaxy (VLSR ∼ 1120 km s −1). Symmetrically bracketing the systemic velocity, the H2O emission covers a velocity range of ∼450 km s −1 with only one p...

A fundamental understanding of the interactions between coadsorbed water and hydrogen on metallic surfaces is critical to many chemical processes including catalysis and electrochemistry. Here, we report on the strong and intricate interactions between coadsorbed H/D and water on the close-packed (111) surface of gold. Deuterium isotopic labeling shows H/D exchange in H-D2O and D-H2O systems, i...

The aim of this study was to compare the measurement of deuterium oxide (D2O) directly in pig serum with that in sublimed whole blood. This was to assess whether excluding vacuum sublimation before analysis would cause any significant loss of accuracy in estimates of pig milk intake. Water and serum standards were made in deionized water and serum, respectively, and were assayed with samples un...

The history and size of the water reservoirs on early Mars can be constrained using isotopic ratios of deuterium to hydrogen. We present new laboratory measurements of the ultraviolet cross-sections of H2O and its isotopomers, and modeling calculations in support of a photo-induced fractionation effect (PHIFE), that reconciles a discrepancy between past theoretical modeling and recent observati...

The ability of West Indian manatees (Trichechus manatus) to move between fresh and salt water raises the question of whether manatees drink salt water. Water turnover rates were estimated in captive West Indian manatees using the deuterium oxide dilution technique. Rates were quantified in animals using four experimental treatments: (1) held in fresh water and fed lettuce (N=4), (2) held in sal...

The reaction talc 1 forsterite 5 enstatite 1 H2O has been investigated between 6 and 20 kbar. Previous high-pressure experimental studies suggested various reaction positions, mostly with positive P-T slopes. The new results show that the reaction has a negative slope in the pressure range studied. It was bracketed between 640 and 680 8C at 10 kbar, between 620 and 640 8C at 15 kbar, and betwee...

We propose an innovative approach for analysing ground-based FTIR spectra which allows us to detect variabilities of lower and middle/upper tropospheric HDO/H 2 O ratios. We show that the proposed method is superior to common approaches. We estimate that lower tropospheric HDO/H 2 O ratios can be detected with a noise to sig-5 nal ratio of 15% and middle/upper tropospheric ratios with a noise t...