Cryptomys hottentotus has no access to dietary or endogenous sources of cholecalciferol (D,). Serum concentrations of calcifediol (25(OH)D,) were undetectable ( < 5 ng/ml) and calcitriol (1,25(OH),D3), although detectable in plasma, was at a low concentration (31.40 (SEM 3.06 pglml). Despite their naturally impoverished vitamin D status, these animals exhibited highly efficient mineral absorpti...

Methanogenic aggregates, harvested from an upflow anaerobic sludge blanket reactor treating potato starch wastewater, were acclimatized to either glucose or a mixture of sugars and organic nitrogen compounds (i.e., diluted molasses). Both types of granules exhibited internal pH and substrate concentration gradients in mineral medium (pH 7.0, 30 degrees C) as was measured with microelectrodes. G...

Cryptomys hottentotus has no access to dietary or endogenous sources of cholecalciferol (D3). Serum concentrations of calcifediol (25(OH)D3) were undetectable (< 5 ng/ml) and calcitriol (1,25(OH)2D3), although detectable in plasma, was at a low concentration (31.40 (SEM 3.06 pg/ml). Despite their naturally impoverished vitamin D status, these animals exhibited highly efficient mineral absorptio...

The presence and concentration of mineral nutrients and organic acids were analyzed in root xylem sap of mature beech trees (Fagus sylvatica L.). An interdependence between malate concentration, pH, and calcium and magnesium concentrations was observed. Significant correlations were found between low pH values and high calcium and magnesium concentrations, low pH values and high malate concentr...

Tendon attaches to bone across a functionally graded interface, "the enthesis". A gradient of mineral content is believed to play an important role for dissipation of stress concentrations at mature fibrocartilaginous interfaces. Surgical repair of injured tendon to bone often fails, suggesting that the enthesis does not regenerate in a healing setting. Understanding the development and the mic...

Phytate and mineral cations are both considered as important dietary factors for inhibiting the crystallisation of calcium oxalate kidney stones in susceptible individuals. In this paper, the phytate and mineral composition of whole bran cereals (wheat, barley and oat) and legumes were determined together with their soluble and insoluble oxalate concentrations in order to investigate the effect...

Lead concentrations was measured in samples of mineral mixtures used in beef cattle feed in the states of Sao Paulo, Paraná, Mato Grosso and Mato Grosso do Sul, Brazil. Lead content was determined by inductively coupled plasma atomic emission spectrometry. Of the 60 analyzed samples, 21 had values greater than 30 ppm (range less 1.6 to 460 ppm), which is the maximum concentration recommended. T...

This paper describes the determination of Fe and Mn in thirty-six mineral waters of Galicia (NW Spain) by means of atomic absorption spectrophotometry (AAS) with an air/acetylene flame. In most cases iron was determined without modifying its concentration after checking its oxidation state in situ. Manganese was determined after concentration by evaporation. Recovery and reproducibility are goo...