Dual-energy X-ray absorptiometry (DXA) and isotope dilution technique have been used as reference methods to validate the estimates of body composition by simple field techniques; however, very few studies have compared these two methods. We compared the estimates of body composition by DXA and isotope dilution (18O) technique in apparently healthy Indian men and women (aged 19-70 years, n 152,...

Oxygen-isotope composition of the solar wind returned by GENESIS indicates that the Sun is 16 O-rich (Δ 17 O SMOW = −26±6‰) [1], supporting one of predictions of the CO self-shielding models [2−4]. The self-shielding models [3,4] assume that both the solids and gas were similarly 16 O-rich (Δ 17 O ~ −25‰), and solids subsequently evolved towards the terrestrial value as a result of CO self-shie...

Bottled and packaged waters are an increasingly significant component of the human diet. These products are regulated at the regional, national, and international levels, and determining the authenticity of marketing and labeling claims represents a challenge to regulatory agencies. Here, we present a dataset of stable isotope ratios for bottled waters sampled worldwide, and consider potential ...

The carbon isotope fractionation associated with nocturnal malic acid synthesis in Kalanchoë daigremontiana and Bryophyllum tubiflorum was calculated from the isotopic composition of carbon-4 of malic acid, after appropriate corrections. In the lowest temperature treatment (17 degrees C nights, 23 degrees C days), the isotope fractionation for both plants is -4 per thousand (that is, malate is ...

It has recently been shown that the iron isotopic composition of blood differs between individuals and sexes, which is supposed to reflect individual differences in iron metabolism. We hypothesized that patients suffering from hereditary hemochromatosis would demonstrate alterations in the iron isotopic composition of blood due to persistent up-regulation of intestinal iron absorption. Blood fr...

BACKGROUND The natural ratios of carbon (C), nitrogen (N), and sulfur (S) stable isotopes can be varied in some specific living organisms owing to various isotopic fractionation processes in nature. Therefore, the analysis of C, N, and S stable isotope ratios in ginseng can provide a feasible method for determining ginseng authenticity depending on the cultivation land and type of fertilizer. ...

One hundred fifty-six biogenic calcites and 96 whole rock carbonate samples of Paleozoic and Mesozoic age have been analysed for their sulfur isotopic composition. Recorded in structurally substituted sulfate (SSS) in the calcite lattice, the sulfur isotopic composition is thought to reflect the sulfur isotope value of ambient seawater sulfate. Possible alterations of the signal have been asses...

The abundances of neon and several other isotopic ratios in the galactic cosmic rays (GCRs) have been measured using data from the Cosmic Ray Isotope Spectrometer (CRIS) aboard the Advanced Composition Explorer (ACE). We have derived the Ne/Ne ratio at the cosmic-ray source using the measured Ne, F, and O abundances as “tracers” of secondary isotope production. Using this approach, the Ne/Ne ab...

Ultraviolet laser microprobe analyses of a calcium-aluminum-rich inclusion (CAI) from the Allende meteorite suggest that a line with a slope of exactly 1.00 on a plot of delta (17)O against delta (18)O represents the primitive oxygen isotope reservoir of the early solar nebula. Most meteorites are enriched in (17)O and (18)O relative to this line, and their oxygen isotope ratios can be explaine...

Fibers are often found at crime scenes and current methods can determine the chemical composition and color of the fiber as well as physical characteristics. Unless the fiber contains DNA, there is no way to compare a fiber found at a crime scene with fibers found in a suspect’s possession. This study aims to determine if isotope ratio mass spectrometry (IRMS) can be used to add an additional l...