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Pressure-induced invar effect in Fe-Ni alloys

A study was conducted to quantify the extraordinary feature of materials of becoming easier to squeeze when pressure is applied to them. This feature was verified by measurements of P-V relations for cubic iron-nickel alloys for three different compositions: Fe0.64Ni0.36, Fe0.55Ni0.45, and Fe0.20Ni0.80.

Stability of KAlSi3O8 hollandite-type structure in the earth's lower mantle conditions

The stability of KAISi3O8 hollandite-type structure is investigated in a series of synthesis experiments between 20 and 95 GPa at 650(±50) °C and between 1200 to 2300 °C, using electrically- and laser-heated diamond anvil cells, respectively. Potassium feldspar transformed to a hollandite-type structure in the experimental pressure range from 20 to 95 GPa at temperatures between 1200 to 2300 °C, w

Bulk modulus and non-uniform compression of Nb3Te4 and InxNb3Te4 (x <1) channel compounds

The crystal structures of Nb3Te4 and InxNb3Te4 [x = 0.539 (4)] are reported for a series of pressures between 0 and 40 GPa. Both compounds crystallize in space group P63/m with a = b = 10.671 and c = 3.6468 Å for Nb3Te4, and a = b = 10.677 and c = 3.6566 Å for InxNb3Te4 at ambient conditions. Phase transitions were not observed. High-pressure X-ray powder diffraction was measured using a diamond a

TIF and PbO under high pressure : Unexpected persistence of the stereochemically active electron pair

Even under a pressure of 46 GPa, the low-symmetry lone-pair structures of isoelectronic TIF and PbO (see picture for β-PbO), classic examples of systems with a stereochemically active lone pair, resist transformation into the corresponding high-symmetry NaCl and CsCl structures. Ab initio calculations allowed a simple bonding picture for lone-pair structures involving inert-pair elements to be dev

Ultrastructure of the epiphyseal plate of the guinea pig in experimental scurvy

The ultrastructure of the upper tibial epiphyseal plate during the development of acute, experimental scurvy in the guinea pig was investigated. The cartilage was examined after the animals had been maintained, under standardized conditions, on a scorbutogenic diet for 8, 15, or 23 days. Progressive fine structural changes were observed in the experimental animals. Within the chondrocytes, the cis

In vitro studies on the effect of in vivo zinc deficiency on the formation of glycos-aminoglycans in rat costal cartilage

The effects of in vivo zinc deficiency and restricted food intake, on the in vitro synthesis of glycosaminoglycans of rib cartilage were studied in the rat. 35S-sulfate and 14C-glucosamine were used as precursors. The glycosaminoglycans were separated on microcolumns and specific radioactivities determined for the different fractions. Chemical analyses showed that zinc deficiency or reduced food i

Ion exchange chromatography of glucosamine and galactosamine in microgram amounts with quantitative determination and specific radioactivity assay

A rapid method for the separation and quantitative determination, including radioassay, of glucosamine and galactosamine in microgram amounts is described. It is based upon the use of a column of Aminex A-5 ion exchange resin eluted with a phosphate buffer at pH 7.00 and 60 °C. From each fraction half the volume is used for a scaled down Elson-Morgan procedure and other half for liquid scintillati

Electron microscopic demonstration of proteoglycans in guinea pig epiphyseal cartilage

Guinea pig epiphyseal cartilage was studied ultrastructurally after staining with ruthenium red or Alcian Blue. Extracellularly, the matrix granules were positively stained with both dyes, whereas no apparent staining of the collagen fibrils occurred. Intracellularly, a positive ruthenium red staining of the Golgi vacuole granules was observed. No Alcian Blue staining of the content of the vacuole

Chemical and metabolic heterogeneity of chondroitin sulfate and keratan sulfate in guinea pig cartilage and nucleus pulposus

Chondroitin sulfate and keratan sulfate in guinea pig costal cartilage, nasal septum cartilage and nucleus pulposus were separated and fractionated by chromatography on CPC-cellulose, ECTEOLA-cellulose and Sephadex G-200 columns. Characterization of the chondroitin sulfates included determination of molecular weight and of the number, and position, of sulfate groups of the disaccharide units. Dist