Carbon (C/C) and nitrogen (N/N) stable isotope ratios were longitudinally measured in human hair that reflected the period from pre-conception to delivery in 10 pregnant women. There was no significant change in the dC results, but all subjects showed a decrease in dN values ( 0.3 to 1.1%) during gestation. The mechanisms causing this decrease in hair dN have not been fully elucidated. However,...

Results of X-Ray Diffraction (XRD) analysis, Triple Oxygen Isotope analysis and Scanning Electron Microscopic (SEM) studies are presented for stone fragments recovered from the North Central Province of Sri Lanka following a witnessed fireball event on 29 December 2012. The existence of numerous nitrogen depleted highly carbonaceous fossilized biological structures fused into the rock matrix is...

Chemoautotrophic symbionts of deep sea hydrothermal vent tubeworms are known to provide their hosts with all their primary nutrition. While studies have examined how chemoautotrophic symbionts provide the association with nitrogen, fewer have examined if symbiont nitrogen metabolism varies as a function of environmental conditions. Ridgeia piscesae tubeworms flourish at Northeastern Pacific ven...

An earlier report (1) dealing with the distribution of isotopic nitrogen in cells of Axotobacter vinelandii fixing molecular nitrogen provided evidence that ammonia might be the initial stable form of nitrogen in the fixation process. This conclusion was based on the observation that the N’s supplied this organism accumulated in the glutamic acid fraction, as had been already observed in higher...

This is a nice paper presenting their data on nitrogen transformation in particular nitrogen loss at deep-sea diffuse vents. Through their data, they could determine the potential rates of denitrification, annamox, and DNRA using 15N paired isotope techniques. Their result suggested that bacterial denitrification is the dominant nitrogen elimination process in sulfidic hydrothermal vent waters....

Stable isotope ratios (δ13C and δ15N) have been used extensively to trace nutrients from Pacific salmon, but salmon transfer more than carbon and nitrogen to stream ecosystems, such as phosphorus, minerals, proteins, and lipids. To examine the importance of these nutrients, metrics other than isotopes need to be considered, particularly when so few studies have made direct links between these n...

Isotope ratio monitoring following on-line combustion is a new method in gas chromatography/mass spectrometry (GC/MS) that allows the ratios of abundances of stable isotopes of elements such as carbon and nitrogen to be determined for individual compounds introduced via a gas chromatograph. It is the first combustion method that allows direct measurement of isotope ratios of individual molecula...

We have developed a transportable spectroscopic nitrogen isotopic analyzer. The spectrometer is based on dual-modulation Faraday rotation spectroscopy of nitric oxide isotopologues with near shot-noise limited performance and baseline-free operation. Noise analysis indicates minor isotope ((15)NO) detection sensitivity of 0.36 ppbv·Hz(-1/2), corresponding to noise-equivalent Faraday rotation an...

A pilot study was performed to examine the potential of stable isotope techniques for monitoring the impact of a harmful substance on the cellular nitrogen metabolism in the ciliate species Tetrahymena pyriformis. After identical cultivation periods of control cells and toluene-exposed cells in a defined culture medium enriched with [guanidino-15N2]l-arginine, a number of nitrogen-containing po...