[en] The triphenylphosphiniminium cation (Ph₃P=NH₂⁺) was evaluated for its selectivity for the pertechnetate anion (⁹⁹TcO₄^-) using both solvent extraction and solid phase extraction methods. The solid phase extraction of TcO₄^- using trimethylsilyl-protected triphenylphosphinimine coated silica gel demonstrated the selectivity of the triphenylphosphiniminium cation for TcO₄^- over a variety of inorganic (NO₃^-, Cl^-, H₂PO₄^-, HSO₄^-/SO₄^2-) and organic (fumarate) anions in aqueous solution (> 98% extracted when at pM TcO₄^- vs. 0.15 M anion). Iodide, lactate, benzoate and acetate were able to compete with pertechnetate (only 11-83% extracted) when present in large excess (0.15 M anion vs. 10^-12 M ^99mTcO₄^-), but not when the anion was present in a 10-fold excess. The triphenylphosphiniminium cation was significantly selective for TcO₄^- over ReO₄^-, a commonly used non-radioactive analog for ⁹⁹Tc, when tracer amounts of both competed with the anions iodide, lactate, benzoate and acetate. (orig.)

[en] Dissolution of geological reference materials by fusion with ammonium bifluoride, NH_4HF_2 or ABF, was evaluated for its potential use in post-detonation nuclear forensics. The fusion procedure was optimized such that the total dissolution time was <3 h without compromising recovery. Geological reference materials containing various levels of silicates were dissolved and measured by ICP-MS to quantify elemental recovery. Dissolutions of NIST 278 obsidian and urban canyon matrix were performed with radiotracer spikes to measure potential loss of volatile elements during the fusion procedure via gamma-ray spectroscopy. Elemental percent recoveries obtained by ICP-MS were found to be 80-120% while recoveries of radiotracers were observed to be 90-100% with the exception of iodine.

[en] Toenail samples were collected from 129 carpenters (average age 47). The bone and blood lead data for these carpenters have shown a broad range of lead-level exposure in this population. A total of 28 elements were measured in the sample set by a combination of instrumental neutron activation analysis (INAA) and graphite furnace atomic absorption spectrometry (GFAAS) methods. Of the elements measured only Co,Cr, Fe, Na, Cd, Cu, F, and Ni were significantly correlated with lead. A statistical treatment of the overall data set, including principal component analysis, was further applied in an attempt to correlate the elements in the samples. (author). 18 refs., 6 figs., 5 tabs

[en] There is significant interest in reducing the timeline for post detonation nuclear debris examination. A critical need is rapid dissolution of refractory nuclear debris to facilitate measurement of key radioisotopes and isotope ratios. Field deployable, rapid dissolution and analysis methods could significantly shorten the attribution analysis timeline. The current practice uses HF in combination with other acids to attack silicates and other refractory minerals expected in debris samples. However, techniques requiring HF are not amenable to use in the field. The fluorinating agent ammonium bifluoride (ABF) is a potential field deployable substitute for HF. In this work we report on the use of in-direct sonication with ABF as a means to improve low-temperature acid digestion of seven USGS and NIST geological reference materials. Using this method, elemental recoveries for USGS reference materials DNC-1a Dolerite, QLO-1a Quartz Latite, SDC-1 Mica Schist, and BHVO-2 Hawaiian Basalt were quantitative while the recovery of elements in USGS AGV-2 Andesite and NIST SRM 278 Obsidian and 1413 High Alumina Sand were low.

[en] Adrenal hemorrhage and renal vein thrombosis are two distinct vascular entities encountered in the new born period. Occasionally, both entities may co-exist in the same patient. A premature infant of a diabetic mother presented with intestinal obstruction secondary to extrinsic compression by the mass effect of the enlarged hemorrhagic adrenal and thrombosed kidney on the left hemicolon, a phenomenon which to our knowledge has not previously been described. (orig.)

[en] The complexation reactions of the ^99mTc(I)- (CO)₃(OH₂)₃⁺ precursor with tris-hydroxymethylenephosphine (THP) and a diphosphine ligand analogue (HMPE) were studied at tracer levels. Results demonstrate rapid formation of ^99mTc(I)(CO)₃⁺ complexes with both THP and HMPE. In the presence of excess THP, conversion of initial complexes to stable, well-defined ^99mTc species occurs indicating coordination of phosphine groups to Tc(I) at all three sites trans to the carbonyl ligands

[en] A new experimental system was designed to measure radon uptake by solid adsorbents from air or other carrier gases/vapors. The total amount of radon adsorbed corresponding to a specific gas-phase concentration was determined by simultaneously measuring the solid-phase and gas-phase concentrations. The system was used to measure radon adsorption isotherms on BPL activated carbon at 288, 298, and 308 K and on silica gel and molecular sieve 13X at 298 K. The isotherms were of type III according to Brunauer's classification. The heat of adsorption data indicated that the BPL activated carbon provided a heterogeneous surface for radon adsorption. The equilibrium data were correlated by the Freundlich equation. In this paper the possible adsorption mechanism and the use of the adsorption isotherms to measure indoor radon concentrations are discussed

[en] This paper describes how the RELAP5 thermal-hydraulic transient code has been applied to a reactor safety analysis of a loss-of-coolant accident (LOCA) to a reactor with thin fuel plates operating at highly subcooled conditions, --75⁰C below boiling temperatures at operating pressure, 25⁰C below boiling conditions at atmosphere pressure that occurs immediately following the LOCA. Depressurization is not the critical issue in this case, but plate boiling and reflooding and mixing of vapor and liquid streams are the critical aspects of the calculation. The analysis of the results shows the sensitivity of the calculation to the time periods of the steam ''chugging'' effects in the water channels between fuel plates. This MOD2 version is the first version which which the authors found consistency and realism in the results calculated for these very difficult transient conditions

[en] The strong focusing of neutron beams by reflection from two bent crystals in antiparallel (+, +) setting is discussed. A previous analysis made for thin perfect crystals is extended, by numerical computations, to the case of a thick and mosaic first crystal. It is concluded that microfocusing is also achievable with flat mosaic first crystals. The combination of strong beam focusing onto sample with narrow diffraction lines in a given limited range, which is a requirement in stress scanning, is further examined. Results of test measurements, with a flat mosaic thick silicon as a first crystal and pneumatically bent thin silicon as a second crystal, are presented. The strong focusing of the beam onto sample is confirmed to be compatible with the focusing in scattering. The feasibility of microfocus diffraction on existing three-axis instruments with flat mosaic monochromators is also confirmed. Techniques for plastic bending of high-reflectivity crystals will have to be developed to take full advantage of microfocusing. (orig.)

[en] Ph₃PNSiMe₃ reacts with ^99mTcO₄^- to form an ion pair that is soluble in organic solvents. Heating of the ion pair produces a new ^99mTc species that is neutral and lipophillic and stable in dry toluene for ≥ 2h. Dissolving this new complex in 1:1, EtOH:H₂O results in conversion of the product back to the ion pair which will limit its in vitro and in vivo stability. The chromatographic properties of the ion pair and the ^99mTc species produced when heated in toluene are similar to the analogous Re complexes with Ph₃PNSiMe, which should have the following respective structures: [Ph₃PNH₂⁺][^99mTcO₄^-] and Ph₃PN^99m TcO₃. These results indicate the potential of phosphinimine ligands in formulation of new ^99mTc radiopharmaceuticals, particularly if phosphinimine ligand derivatives are developed that provide substantially improved stability of the respective complexes in aqueous solutions. (author)