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- Author or Editor: M. Peterson x
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Abstract
Northeastern Atlantic sedimentary rare earth element (REE) (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) phase associations among CaCO3, authigenic and lithogenic material are estimated from total sediment REE, Al, Ca, Si, Mn and Co abundances using a linear correlation technique. Phase associations were also determined using a selective chemical leaching technique specific for CaCO3+exchangeable cation, easily reducible oxyhydroxide and residual material. Results suggest that 25–50% of the REE associated with the clay material are exchangeable cations and 20–35% of the total 3+REE and 4% of the total Ce reside in coatings on the CaCO3 tests.
Abstract
Detection limits are presented for the platinum metals in vegetation for different neutron activation analysis conditions, namely, short irradiation, cyclic and long irradiations both thermally and epithermally. These detection limits for instrumental neutron activation analysis are compared with those using preconcentration technique—dry ashing and fire assay and post irradiation separation of the platinum metals using Srafion NMRR in exchange resin. The results are evaluated for plant material and it is concluded that dry ashing followed by cyclic, epithermal irradiation for rhodium and palladium and long, thermal irradiations for osmium, platinum, iridium and ruthenium enable these elements to be detected in plants at background levels.
Abstract
One formulation of14C labeled and another of99mTc labeled 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) were administered i.v. to tumor (glioma) bearing rats. The radiopharmacokinetics of14C-CCNU were followed up to 24 hours post injection. On a per organ basis the blood, liver, small bowel, kidney cortex and muscle contained most of the activity. Optimum tumor to organ ratios occurred at 4–12 hours. The99mTc-CCNU biodistribution was determined at 4 hours and compared to99mTc-NaTcO4. Tumor capsule to brain (29.5) and to muscle (10.59) ratios suggest99mTc-CCNU to be a potential tumor seeking agent.
Abstract
Researchers from the Savannah River Technology Center, the Center for Applied Isotope Studies (CAIS) and Sampling Systems have developed a prototype Field Deployable Tritium Analysis System (FDTAS) for near-real-time measurements of environmental levels of tritium in ground and surface water. The device consists of a modified liquid scintillation counter coupled to an automatic sampler which incorporates on-line water purification. The FDTAS has been field tested at several Savannah River Site locations and has produced results comparable to laboratory analyses for low concentrations of tritium. Figures of merit obtained in the field include an average tritium background count rate of 1.5 counts per minute (cpm), tritium detection efficiency of ≈25%, and a detection limit of <10 Bq/l for a 100 minute count.
