Element Interiors Research Articles

The solubility problem of heavy elements in internal stellar plasma revisited

Theoretical predictions of the phase separation of heavy elements in internal stellar plasmas, based on the classical Debye-Huckel and mean spherical approximation, have offered a solution to the ‘solar neutrino puzzle’. Recent contributions, however, expressed some doubt about the correctness of these calculations. In the present paper, we challenge the latter conclusions by showing that the linearization of the Poisson-Boltzmann equation can be preformed to avoid the negativity of pair correlation functions, and that the importance of classical charge-charge effects is considerably greater than quantum effects in determining the internal energy of solar plasmas. Comparison between gravity and radiation pressure acting on phase-separated high-Z plasma ‘droplets’ supports the formation of a small ‘iron core’ in the center of the Sun confirming Rouse's suggestion that the frequencies of the non-radialg-modes and the five-min band of oscillations in the Sun can be explained only by the existence of such a core. The depletion of the Sun's interior of heavy elements results in a decreased opacity and, consequently a higher temperature which finally leads to a chlorine neutrino signal of about 2.5 solar neutrino unit in agreement with Davies's experimental result. Essentially the same high neutrino capture rate as given by the present standard Sun model is predicted for the future gallium experiment. This prediction is in contrast to the neutrino oscillation hypothesis in which a wide range of coupling parameters suppresses both chlorine and gallium signals.

Morphology and molecular composition of isolated postsynaptic junctional structures.

The solubilization of isolated brain synaptosomal plasma membranes by various detergents was studied and in each case found to depend upon detergent concentration. By using conditions sufficient to extract maximally protein and phospholipid from the membranes, postsynaptic junctional particles were isolated with each of four detergents and their ultrastructural appearances and protein contents compared. Two basic structural forms were identified. One, isolated with Triton X-100, consists of a planar array of dense-staining particles ca. 20 nm in diameter. It resembles the postsynaptic density seen in undigested synaptosomal plasma membranes. The other, isolated with sodium deoxycholate, contains less protein. It has the same overall shape and dimensions as the postsynaptic density, but consists of a branching network of short 5 nm fibres (the postsynaptic junctional lattice) making up an array of contiguous polygons, each ca. 20 nm across. The interior of these polygonal elements seems to be hydrophobic since it cannot be penetrated by metallic salts used for negative staining. It is suggested that the dense-staining 20 nm subunits observed at the postsynaptic junctional site may be composed of hydrophobic proteins inserted into the hollow cores of the lattice polygons. Electrophoretic analysis of the proteins present in the various postsynaptic junctional preparations identified two major common components with molecular masses of 275000 and 47500. The latter is tentatively identified as actin. Components comigrating respectively with alpha- and beta-tubulin are present, and the relation of the lattice structure to subjacent microtubules is discussed.