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We recently published electron paramagnetic resonance (EPR) spin trapping results that demonstrated the enzymatic reduction of sulfur mustard sulfonium ions to carbon-based free radicals using an in vitro system containing sulfur mustard, cytochrome P450 reductase, NADPH, and the spin trap α-(4-pyridyl-1-oxide)- N - tert -butylnitrone (4-POBN) in buffer (A.A. Brimfield et al., 2009, Toxicol. Appl. Pharmacol. 234:128–134). Carbon-based radicals have been shown to reduce molecular oxygen to form superoxide and, subsequently, peroxyl and hydroxyl radicals. In some cases, such as with the herbicide paraquat, a cyclic redox system results, leading to magnified oxygen free radical concentration and sustained tissue damage. Low mustard carbon radical concentrations recorded by EPR in our in vitro system, despite a robust (4.0 mM) sulfur mustard starting concentration, led us to believe a similar oxygen reduction and redox cycling process might be involved with sulfur mustard. A comparison of the rate of mustard radical–POBN adduct formation in our in vitro system by EPR at atmospheric and reduced oxygen levels indicated a sixfold increase in 4-POBN adduct formation (0.5 to 3.0 μM) at the reduced oxygen concentration. That result suggested competition between oxygen and POBN for the available carbon-based mustard radicals. In parallel experiments we found that the oxygen radical-specific spin trap 5- tert -butoxycarbonyl-5-methylpyrroline- N -oxide (BMPO) detected peroxyl and hydroxyl radicals directly when it was used in place of POBN in the in vitro system. Presumably these radicals originated from O 2 reduced by carbon-based mustard radicals. We also showed that reactive oxygen species (ROS)–BMPO EPR signals were reduced or eliminated when mustard carbon radical production was impeded by systematically removing system components, indicating that carbon radicals were a necessary precursor to ROS production. ROS EPR signals were completely eliminated when superoxide dismutase and catalase were included in the complete in vitro enzymatic system, providing additional proof of oxygen radical participation. The redox cycling hypothesis was supported by density functional theory calculations and frontier molecular orbital analysis.

The purpose of this assumptions document is to provide general scope, strategy, technical basis, schedule and cost assumptions for the Monitored Geologic Repository (MGR) life cycle cost estimate and schedule update incorporating information from the Viability Assessment (VA), License Application Design Selection (LADS), 1999 Update to the Total System Life Cycle Cost (TSLCC) estimate and from other related and updated information. This document is intended to generally follow the assumptions outlined in the previous MGR cost estimates and as further prescribed by DOE guidance.

Latitudinal trends in plankton 13 C: 12 C significantly differ between northern and southern oceans. The results corroborate previous that (1) a strict temperature-plankton 13 C: 12 C relationship common to all oceans does not exist, and (2) geographic differences in plankton biosynthesis or metabolism are important in causing latitudinal variations in plankton carbon isotope abundance.

A submersible dive on a turbidite-covered spreading axis in Guaymas Basin photographed and sampled extensive terraces and ledges of talc. The rock contains siliceous microfossils, smectite, and euhedral pyrrhotite as well as rather pure iron-rich talc. Sulfur and oxygen isotopes indicate precipitation around a hydrothermal vent, at about 280°C.

In comparing a control vs. a sewage-affected nearshore site off southern California, the natural relative abundances of 13C, 15N and D in Dover sole and Ridgeback prawn muscle were found to be significantly different. This between-site shift in animal isotope abundance is of the type expected if sewage organic materials were an important food source for animals in the latter site. Use of stable isotope natural abundance to trace the incorporation and movement of sewage-derived organics in marine food webs is suggested.

During intervals in 1967-1970, the OGO-4 and 6 spacecraft made over 2000 traversals over the equatorial electrojet in the altitude range 400-800 km when local times were between 9 and 15 hr. These spacecraft carried total field magnetometers making measurements to an accuracy of 2 gammas with a sample rate greater than once a second. Delta-F values, the deviations of these observations from an internal reference model, were plotted for a 30 deg band about the Equator, and the characteristics of the electrojet effect in the data were investigated. This effect was characterized by a sharp negative V-signature of some 16-19 deg in width and a variable amplitude.