Plutonium process control using an on-line gamma monitor for uranium,plutonium, and Americium

An On-Line Gamma Monitor profiles the concentration of uranium, plutonium, and americium in waste and product streams of the anion exchange process used to purify plutonium at Los Alamos. The Monitor employs passive gamma Spectrometry to measure the 59.5-KeV and 129-KeV gamma rays of²⁴¹Am and²³⁹Pu, respectively. Because the uranium impurity in typical process streams has no gamma ray suitable for passive measurement, a novel radiotracer technique is used. Uranium-237, always present in plutonium processed at Los Alamos as a minor alpha-decay daughter of²⁴¹Pu, has a 6.8-day half-life and 208-KeV gamma energy, which make it an ideal radiotracer for macro amounts of uranium in the process. The On-Line Gamma Monitor is used routinely to provide Los Alamos operators with continuous, real-time process control information.     

Polyoxometalate Derivatives with Multiple Organic Groups. 2. Synthesis and Structures of Tris(organotin) alpha, beta-Keggin Tungstosilicates

Eight tris(organotin)-substituted Keggin tungstosilicate heteropolyanions have been synthesized and characterized by elemental analysis, infrared and M?ssbauer spectroscopy, multinuclear NMR, and X-ray crystallography. The new anions contain alpha- or beta-SiW(9)O(34)(10)(-) moieties and are of two structural types, [(RSn)(3)(SiW(9)O(37))](7)(-) (R, isomer: Ph, alpha-, 1; n-Bu, alpha-, 2; Ph, beta-, 3; n-Bu, beta-, 4) and [(RSnOH)(3)(SiW(9)O(34))(2)](14)(-) (Ph, alpha-, 5; n-Bu, alpha-, 6; Ph, beta-, 7; n-Bu, beta-, 8). Crystals of Cs(4)H(3)[(PhSn)(3)(SiW(9)O(37))].8H(2)O (anion 3) are monoclinic, space group C2/c, with lattice constants a = 48.91(2) ?, b = 12.111(3) ?, c = 20.334(9) ?, beta = 102.30 degrees, and Z = 8. The anion has nominal C(3)(v)() symmetry and has a structure with three corner-shared WO(6) octahedra of the beta-Keggin anion replaced by three PhSnO(5) groups. Crystals of Cs(9)H(5)[(BuSnOH)(3)(SiW(9)O(34))(2)].36H(2)O (anion 6) are tetragonal, space group P&fourmacr;2(1)m, with lattice constants a = b = 29.005(4) ?, c = 13.412(4) ?, and Z = 4. The anion has the anticipated D(3)(h)() symmetry and contains three BuSnOH groups sandwiched between A,alpha-SiW(9)O(34)(10)(-) anions.     

Anomalies and curvature ofW manifolds

We study the holomorphic structure of certain complex manifolds associated withW algebras, namely, the flag manifoldsW /T andW ₁₊/T ₁₊, and the spacesW /SL(),R) andW ₁₊/GL(,R), whereT andT ₁₊ are the maximal tori inW andW ₁₊. We compute their Ricci curvature and show how the results are related to the anomaly-freedom conditions forW andW ₁₊. We discuss the relation of these manifolds with extensions of universal Teichmüller space.Supported in part by the U.S. Department of Energy, under grant DE-AS05-81ER40039Supported in part by the U.S. Department of Energy, under grant DE-FG03-84ER40168     

The spontaneous release of a high-molecular-weight aggregate containing immunoglobulin G from the surface of Ehrlich ascites tumor cells

The spontaneous release of tumor cell antigens from the cell surface into the circulation has been proposed as a mechanism whereby tumors may escape the immune response of the host. In this study we have found that Ehrlich ascites tumor cells after removal from the host (mouse) spontaneously release significant amounts of cell surface components during incubation for 1 h in cold isotonic buffer. Immunodiffusion studies revealed that immunoglobulin G (IgG) and a complement component (C3) are included in this spontaneously released material. These surface-bound humoral immune components are apparently released in the form of a high-molecular-weight aggregate (cell coat particle) as shown by ultracentrifugation and ultrafiltration experiments. Precipitation of IgG from the cell coat particle preparation with antibodies directed against mouse IgG followed by detergent gel electrophoresis of the immune precipitate revealed five major bands in addition to the heavy and light chains of IgG. These results suggest that host IgG is tightly bound to several other components at the cell surface, perhaps in the form of immune complexes. IgG is localized on the tumor cell surface in a highly heterogenous pattern with the appearance of patches and caps in some cells as shown by immunofluorescence analysis. The possibility that humoral immune components bind to the tumor cell surface and result in the shedding of high-molecular-weight aggregates of cell surface antigens into extracellular fluids is discussed.     

Chiral polyoxotungstates. 1. Stereoselective interaction of amino acids with enantiomers of [Ce(III)(alpha1-P2W17O61)(H2O)x]7-. The structure of DL-[Ce2(H2O)8(P2W17O61)2]14-

The ammonium salt of the 1:1complex (1) of Ce(III) with alpha(1)-[P(2)W(17)O(61)](10)(-) was prepared and characterized by elemental analysis, vibrational and NMR spectroscopy ((31)P, (183)W), cyclic voltammetry, and single-crystal X-ray analysis (P1; a = 15.8523(9) A, b = 17.4382(10) A, c = 29.3322(16) A, alpha = 99.617(1) degrees, beta = 105.450 (1) degrees, gamma = 101.132(1) degrees, V = 7460.9(7) A(3), Z = 2). The anion consists of a centrosymmetric head-to-head dimer, [[Ce(H(2)O)(4)(P(2)W(17)O(61))](2)],(14-) with each 9-coordinate Ce cation linked to four oxygens of one tungstophosphate anion and to one oxygen of the other anion. On the basis of P NMR spectroscopy, a monomer-dimer equilibrium exists in solution with K = 20 +/- 4 M(-1) at 22 degrees C. Addition of chiral amino acids to aqueous solutions of 1 results in splitting of the (31)P NMR signals as a result of diastereomer formation. No such splitting is observed with glycine or DL-proline, or when chiral amino acids are added to the corresponding complex of the achiral alpha(2)-isomer of [P(2)W(17)O(61)](10)(-). From analysis of the (31)P NMR spectra, formation constants of the two diastereomeric adducts of 1 with L-proline are 7.3 +/- 1.3 and 9.8 +/- 1.4 M(-1).     

Polyoxometalate Derivatives with Multiple Organic Groups. 3. Synthesis and Structure of Bis(phenyltin) Bis(decatungstosilicate), [(PhSnOH(2))(2)(gamma-SiW(10)O(36))(2)](10)(-)

A new phenyltin tungstosilicate derivative, [(PhSnOH(2))(2)(gamma-SiW(10)O(36))(2)](10)(-) (1), has been prepared by reaction of phenyltin trichloride with K(8)[gamma-SiW(10)O(36)].xH(2)O. The new heteropolyanion was characterized by elemental analysis, infrared spectroscopy, multinuclear NMR, and X-ray crystallography. The crystals of Cs(9)H[(PhSnOH(2))(2)(gamma-SiW(10)O(36))(2)].16H(2)O (Cs salt of 1) are triclinic, space group P&onemacr;, with lattice constants a = 12.401(3) ?, b = 13.832(3) ?, c = 16.313(3) ?, alpha = 96.17(2) degrees, beta = 109.73(2) degrees, gamma = 97.13(2) degrees, V = 2579.9(10) ?, and Z = 1. Anion 1 has a structure of virtual C(2)(h)() symmetry with two phenyltin groups sandwiched between two gamma-SiW(10) groups. Such a structure is different from all previously reported polytungstates derived from [gamma-SiW(10)O(36)](8)(-) lacunary anions.