PubMed · 4114604
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F B Johnson. 1972. Crystals in pathologic specimens.. https://pubmed.ncbi.nlm.nih.gov/4114604/
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Chemical analysis of spent Co/Mo/gamma Al(2)O(3) catalyst revealed the presence of carbon, molybdenum, sulfur, vanadium and cobalt at levels of 16.0, 10.9, 7.3, 4.6 and 4.0 wt.%, respectively. It was found that calcination at 500 degrees C provides an effective solution for the removal of carbon and sulfur and this generates the oxide form of the heavy metals. The removal of these heavy metals can be achieved through a two-stage leaching process. During the first stage, in which concentrated ammonia is used and it has been found that this process can be successful in removing as much as 83% (w/v) Mo. In a second stage, it was found that using 10% (v/v) of sulfuric acid, it was possible to account for up to 77% (w/v) Co and 4% (w/v) Mo removal. Leaching test results indicated that the vanadium present in the heated spent catalyst was almost stabilized but the molybdenum and cobalt were not. The combination of two solid wastes, ladle furnace slag (LFS) and treated residue of spent catalyst, could be used for making a high value-added anorthite glass-ceramic materials. Further leaching tests showed that ceramic glass materials provided a very effective method of Co, Mo and V heavy metals stabilization resulting in a product with a possible commercial value.
In expanded CAG repeat diseases such as Huntington's disease, proteins containing polyglutamine (poly(Gln)) sequences with repeat lengths of about 37 residues or more are associated with development of both disease symptoms and neuronal intranuclear inclusions (NIIs). Disease physiology in animal and cellular models does not always correlate with NII formation, however, and the mechanism by which aggregate formation might lead to cytotoxicity is unknown. To help evaluate various possible mechanisms, we determined the biophysical properties of a series of simple poly(Gln) peptides. The circular dichroism spectra of poly(Gln) peptides with repeat lengths of five, 15, 28 and 44 residues are all nearly identical and are consistent with a high degree of random coil structure, suggesting that the length-dependence of disease is not related to a conformational change in the monomeric states of expanded poly(Gln) sequences. In contrast, there is a dramatic increase in both the kinetics and the thermodynamic favorability of the spontaneous formation of ordered, amyloid-like aggregates for poly(Gln) peptides with repeat lengths of greater than 37 residues. At the same time, poly(Gln) peptides with repeat lengths in the 15-20 residue range, despite their poor abilities to support spontaneous, self-nucleated aggregation, are capable of efficiently adding to an already-formed aggregate. We also find that morphologically small, finely divided aggregates are much more efficient at recruiting poly(Gln) peptides than are large aggregates, suggesting a possible explanation for why disease pathology does not always correlate with the observable NII burden. Together, these data are consistent with a model for disease pathology in which critical cellular proteins possessing poly(Gln) sequences of modest length become inactivated when they are recruited into aggregates of an expanded poly(Gln) protein.
Halorhodopsin (HR) was investigated with atomic force microscopic techniques (AFM) in aqueous solution. Two-dimensional (2D) crystals of HR were obtained by purifying an HR membrane fraction with the same buoyant density as the purple membrane (HR-PM) from the overexpressing strain Halobacterium salinarum D2. The membrane patches of HR were immobilized on mica. Images with a resolution up to 14 A were recorded. Crystals showed an orthogonal structure and the orientation of the molecules showed p42(1)2 symmetry; thus, alternate tetramers are inverted in the membrane. The crystal surface was found to display different structures depending on the imaging force used, indicating that some parts of the HR molecule are more rigid but others more compressible. From samples with single tetramers missing in the crystalline patches dimensions of the unit cell could be determined. Helix-connecting loops in single molecules of halorhodopsin were assigned. The images indicate that the large extracellular BC loop covers the whole molecule and is very flexible.