The influence of electrolyte impurity species on current efficiency with respect to aluminium (CE) was studied in a specially designed laboratory cell at 980 deg C, with a graphite anode and a ...cathodic current density of 0.85 A cm exp -2 . The electrowinning was performed in a base melt of Na sub 3 AlF sub 6 with a NaF/AlF sub 3 molar ratio of 2.5 and with 4-6 wt% Al sub 2 O sub 3 and 5 wt% CaF sub 2 . Impurity species, probably present in only one valence state in the electrolyte, Mg, Ba and B, had no measurable effect on CE for low impurity concentrations. Sn, added to the electrolyte as SnO sub 2 , also did not affect current efficiency, probably due to its low solubility. The results show a linear decrease in CE with increasing electrolyte concentration of the polyvalent impurity species from the elements, Fe, P, V, Si, Zn, Ti and Ga. The decrease was found to be within the range 0.1 to 0.7% in CE per 0.01 wt% of impurity cations present in the electrolyte, with phosphorus ions as the most detrimental. The effects of the individual impurity species on CE appear to be roughly additive for electrolytes containing more than one impurity species. The results obtained cannot be explained by a simple codeposition mechanism or a single reduction to a soluble species of a lower valency. The most likely mechanism explaining the observed decrease in CE for a large number of impurity species is cyclic redox reactions in the cathode and anode/CO sub 2 interfacial boundary layers. Such a mechanism may also be the dominant one in commercial cells, since the impurity levels are of the same size as in the laboratory cell.
Two cases of cardiac dislocation occurred after intrapericardial right pneumonectomy with extended pericardiectomy and radical nodal dissection in spite of proper reconstruction with a pericardial ...fat flap in one case and with a Gore-tex® prosthesis in the other. In the case of major pericardial excision resulting in extensive mobilisation of the SVC a complete reconstruction of pericardium and mediastinal pleura is recommended in order to prevent cardiac dislocation.
Neoangiogenesis and enhanced glucose metabolism in neoplasms are likely to be activated by the same biochemical stimulus; hypoxia. A correlation between these two parameters has been postulated. The ...objective of this study was to evaluate the relationship between Fluoro-desoxi-glucose uptake at positron emission tomography scan and angiogenesis in lung metastasis. Fluoro-desoxi-glucose activity, expressed as a standard uptake value, and microvessel intratumoural density, were retrospectively calculated in a series of 43 lung metastasis resected in 19 patients. Primary sites were colorectal cancer in 16 metastases, sarcoma in eight, gynaecological in four and other sites in 15. The correlation between the two parameters was tested by logistic regression and multivariate analysis. Positron emission tomography scan was positive in 17 patients (sensitivity 89%). No correlation was observed between standard uptake value and microvessel intratumoural density in this series of lung metastasis. Positron emission tomography negative and positive nodules presented comparable value of microvessel intratumoural density (12.9 vs 11.3). Standard uptake value was significantly correlated with nodules size and was higher in colon cancer metastasis than in sarcoma ones. Microvessel intratumoural density was independent from nodule size but significantly higher in sarcoma than in colon cancer metastasis. The lack of correlation was confirmed by multivariate analysis after adjustment for tumour type and nodules size. The present study demonstrated that positron emission tomography scan is positive in a high proportion of patients regardless of microvessel density. Glucose uptake and angiogenesis appear to be independent biological features in lung metastasis. This observation may have implications for future antiangiogenic therapies.
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