Simultaneous multielement analysis of various human tissues by inductively-coupled plasma atomic-emission spectrometry

Human soft tissues were analysed by inductively-coupled plasma atomic-emission spectrometry (ICP-AES) for twelve elements. The tissues had been vacuum-dried for storage and were dry-ashed at low temperature and then digested with nitric acid prior to analysis. Accuracy and precision were examined by analysing NBS Standard Reference Material 1577 Bovine Liver. For P, K, Na, Mg, Ca, Fe, Cu, Zn and Cd, the concentrations obtained were within 4% of the certified or informational values. It was found that cerebrum, cerebellum, heart, kidney, liver, pancreas, spleen and muscle samples in portions of less than 1 g dry weight could be conveniently analysed for these elements.     

Chromatographic purification of no-carrier-added magnesium-28 for biological studies

The preparation of no-carrier-added²⁸Mg from a pure Al target irradiated by an -particle beam has been developed for biological tracer use. The²⁸Mg was purified, by successive extraction and ion exchange chromatography. One hour irradiations at 5 A of 50 MeV -particles gave approximately 2 Ci of no-carrier-added and practically salt-free²⁸Mg with high radionuclidic purities.     

Thermodynamics and Fluorescence Spectra of 1,10-Phenanthroline in Micelles of Poly (Ethylene Oxide)-Type Nonionic Surfactant

The distribution of 1,10-phenanthroline (phen) in micellar solutions of the nonionic surfactants Triton X and C₁₂E _n with varying poly (ethylene oxide) chain lengths has been studied by potentiometry, calorimetry, and fluorometry at 298 K. Micelles accommodate 1,10-phenanthroline according to the reaction, phen + Y_m = Y_m(phen), where Y_m denotes a surfactant molecule aggregated in micelles. The constant K _m for the reaction of Triton X increases as a linear function of n*, the number of ethylene oxide (EO) groups, as K _m = K_EO n* + K_c. Nonzero K _EO and K _c values suggest a heterogeneous inner structure of the micelle, i.e., the hydrophobic core surrounded by a hydrophilic poly (ethylene oxide) (PEO) shell. On the basis of molar volumes, the intrinsic thermodynamic parameters of transfer of 1,10-phenantholine were extracted. The enthalpy and entropy of transfer of 1,10-phenanthroline from the PEO shell to the core are found to be small and negative. By using K _EO and K _c values for C₁₂E _n obtained by fluorometry, individual fluorescence spectra of 1,10-phenanthroline in the PEO shell and core were extracted. The fluorescence intensity of 1,10-phenathroline accommodated in the core, like in organic solvents, is significantly reduced relative to that in water. These facts indicate that the aromatic rings of 1,10-phenanthroline penetrate into the hydrophobic core, while its hydrophilic N site is still hydrated in the PEO shell.     

Chemical Processing of Potassium Substituted (Pb0.6Ba0.4)Nb2O6 Powders and Thin Films Through Metallo-Organics

Highly oriented tungsten bronze K_0.4(Pb_0.6Ba_0.4)_0.8Nb₂O₆ ferroelectric thin films have been prepared from metal alkoxides and metal acetate by chemical process. The formation of solid solution with potassium was found to be very effective to form the tungsten bronze phase at lower temperatures compared with (Pb_0.6Ba_0.4)Nb₂O₆. The amount of potassium in the composition of K_x(Pb_0.6Ba_0.4)_{1 – x/2}Nb₂O₆ [0 x 0.4] is also important to crystallize in the tungsten bronze phase. K_0.4(Pb_0.6Ba_0.4)_0.8Nb₂O₆ films with c-axis preferred orientation were successfully synthesized on MgO(1 0 0) and Pt(1 0 0)/MgO(1 0 0) substrates above 700°C. KPBN60 thin film on Pt(1 0 0)/MgO(1 0 0) showed a remnant polarization of 20 C/cm² and a coercive field of 140 kV/cm at –150°C.