John S Vogel

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Measurements of carbon-14 in small samples of methane from major biogenic sources, from biomass burning, and in "clean air" samples from both the Northern and Southern hemispheres reveal that methane from ruminants contains contemporary carbon, whereas that from wetlands, pat bogs, rice fields, and tundra is somewhat, depleted in carbon-14. Atmospheric(More)
We present the application of a nonparametric method to performing functional principal component analysis for functional curve data that consist of measurements of a random trajectory for a sample of subjects. This design typically consists of an irregular grid of time points on which repeated measurements are taken for a number of subjects. We introduce(More)
The technique of accelerator mass spectrometry (AMS) was validated successfully and used to study the pharmacokinetics and disposition in dogs of a preclinical drug candidate (7-deaza-2'-C-methyl-adenosine; Compound A), after oral and intravenous administration. The primary objective of this study was to examine whether Compound A displayed linear kinetics(More)
A drug delivery microelectromechanical systems (MEMS) device was designed to release complex profiles of multiple substances in order to maximize the effectiveness of drug therapies. The device is based on micro-reservoirs etched into a silicon substrate that contain individual doses of drug. Each dose is released by the electrochemical dissolution of the(More)
PURPOSE Cellular retinaldehyde-binding protein (CRALBP), transcribed from the RLBP1 gene, is a 36-kDa water-soluble protein with 316 amino acids found in the retinal pigment epithelium (RPE) and in retinal Müller cells. It is thought to play a critical role in the visual cycle by functioning as an acceptor of 11-cis-retinol from the isomerohydrolase(More)
BACKGROUND A quantitative understanding of human folate metabolism is needed. OBJECTIVE The objective was to quantify and interpret human folate metabolism as it might occur in vivo. DESIGN Adults (n = 13) received 0.5 nmol [(14)C]pteroylmonoglutamate (100 nCi radioactivity) plus 79.5 nmol pteroylmonoglutamate in water orally. (14)C was measured in(More)
Modified proteins were detected in liver and bone marrow of mice following treatment with [(14)C]benzene. Stained sections were excised from one-dimensional and two-dimensional gels and converted to graphite to enable (14)C/(13)C ratios to be measured by accelerator mass spectrometry. Protein adducts of benzene or its metabolites were indicated by elevated(More)
The bioavailability and the bioreactivity of the carcinogenic heterocyclic amine [2-14C]2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine (PhIP) have been investigated at a dose approximating that likely from the human diet by accelerator mass spectrometry (AMS). [2-14C]PhIP was administered to mice at a dose equivalent ot the consumption of two 100 g beef(More)
New radiocarbon dates on four artifacts that were thought to provide evidence for human occupation of the Yukon Territory during the upper Pleistocene indicate that all four are of late Holocene age. The original radiocarbon age obtained for one artifact (the so-called "Old Crow flesher") was in error by almost 26,000 years.
Isotope tracer studies, particularly radiocarbon measurements, play a key role in biological, nutritional, and environmental research. Accelerator mass spectrometry (AMS) is now the most sensitive detection method for 14 C, but AMS is not widely used in kinetic studies of humans. Part of the reason is the expense, but costs would decrease if AMS were used(More)