Search

Influence of Nd2O3 in LiF-NdF3-Nd2O3 melt on carbon anode oxidation was investigated by infra-red spectroscopy and electrochemical techniques to prevent CFX(g) formation during Nd metal production. A gas extractor device was developed to provide fast analysis of the electrochemically produced gas: the carbon anode was only oxidized into CO2(g) until a critical current density was reached. For higher values, CF4(g) and C2F6(g) were also produced. It was associated to diffusion limited current density of NdOF5 4−. To avoid CFX(g) production during the process, the influence of Nd2O3 and temperature on this limiting current density was determined by steady-state voltammetry. [ABSTRACT FROM AUTHOR]

Combining thermodynamic database and electrochemical measurements, CeF3 thermodynamics properties were determined between 1113 K and 1233 K in LiF-CaF2 solution. First, standard potentials of CeF3/Ce were calculated in different reference states: liquid and solid, and infinite dilution. Then activity coefficients of CeF3 were estimated in the different reference states and for different composition scales: molarity, molality and molar fraction. Finally, constants which interconnected the infinite dilution reference state and the solid and liquid reference states were evaluated. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the correlation of parameters of bone quality assessed by quantitative ultrasound (QUS) with biochemical indexes of bone resorption. QUS of the calcaneus and the hand phalanges, and biochemical parameters (urinary excretion of pyridinoline [Pyr] and deoxypyridinoline [D-Pyr]) were measured in a group of 30 well-characterized postmenopausal women with established osteoporosis and fragility fractures. All patients were treatment free. QUS data significantly correlated with both urinary Pyr and D-Pyr (p < 0.001 for speed of sound [SOS], broadband ultrasound attenuation [BUA], and stiffness at the heel; p < 0.001 for amplitude-dependent SOS at the proximal phalanges of the nondominant hand). No significant correlation was observed between spine and femoral bone mineral density and the urinary excretion of Pyr and D-Pyr. Results of this study suggest that QUS of bone evaluates characteristics of bone influenced by the bone resorption rate.

Bone mineral density (BMD) of the vertebral spine, appendicular skeleton, and whole body was studied in male athletes who chronically trained by different forms of skeletal loading. Eighteen subjects performed weight-bearing activity (canoeists, n = 18), and 14 performed non-weight-bearing activity (cyclists, n = 14). Twenty-eight age-matched male students served as non-athletic controls. The canoeists had significantly higher spine, pelvic and total body BMD than cyclists and controls. No intergroup difference was observed in the BMD of arms and legs despite the fact that physical activity of canoeists and cyclists were characterized by forceful muscular contractions. It is concluded that weight-bearing activity is essential to obtain beneficial skeletal effects on total and regional bone mass in young subjects.

In order to evaluate the effects of ipriflavone therapy, a clinical and metabolic study was carried out in a group of female patients with low bone mass. In particular, mineral density of the proximal femur was measured, this being a fundamental factor for the resistance of this district. At the end of the 12-months treatment cycle, reduced plasma concentration of Bone Gla Protein and urinary hydroxyproline/creatinine ratio (indicating reduced bone resorption), and a significant increase of bone density of the femoral neck and of the trabecular substructure of Ward's triangle were found. On the whole, treatment was well tolerated.