Malignancy-related hypocalcaemia has received less attention in the literature than the opposite perturbation, hypercalcaemia. Only, scarce and contradictory data exist about hypocalcaemia associated with bone metastases (BMH). We have reviewed the clinical records of 155 patients with bone metastases of solid tumours, 122 of which were followed during the whole course of the disease until death. The frequency of hypocalcaemia ranged from 5 to 13%, depending on the formula used to correct calcium values for protein concentration. BMH was almost exclusively limited to patients with osteoblastic metastases. The frequency of BMH among patients with prostate carcinoma was 13-27%, depending on the formula used. Only two of 60 patients with lytic bone lesions presented hypocalcaemia, and in both cases it was rather mild. The development of hypocalcaemia did not seem to imply a worse prognosis, at least in patients with carcinoma of the prostate. Thus, the prevalence of BMH appears to be higher than is usually considered. Adequate attention should be given to this disorder because of the potentially deleterious effects on several organ systems.

The application of alternative dielectric oils as esters in power transformers is hindered by the lack of knowledge regarding their properties and respecting which are the best techniques to ensure their proper performance. In this sense one of the fields needing an impulse is the impregnation processes of transformers cellulosic materials with these alternative oils, currently impregnated in most of the cases with mineral oils. This paper studies the impregnation behavior of eight usual dielectric solids, with two esters and a traditional mineral oil. Empirical equations of the impregnation evolution with time have been obtained, from these the rigid cellulosic materials present in the transformers and the viscosity of the dielectric oils have been identified as the key materials and properties to consider during impregnation. An adaptation of the current impregnation processes to the alternative oils have been proposed by increasing their temperature from ambient temperature up to 61-74ºC, depending on the viscosity of the oil used. INDEX TERMS dielectric, ester, impregnation, model, transformer, temperatureThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.

Due to the impact of cellulose of paper insulation on transformer life, it is imperatire to remove moisture from the oil and the solid insulation. Several techniques have been implemented during manufacturing of power transformers to reduce water content in transformers. These drying processes can involve different costs and time, and they can damage the insulation paper. In this work, a drying process has been implemented in the laboratory trying to simulate the most aggressive conditions that can be suffered by the paper in transformer manufacturing in a real industry. Then the effect of the drying process on paper was evaluated using the analysis of mechanical and dielectric properties and the degree of polymerization. Different commercial papers were studied to quantify the possible degradation induced by the drying process. The results of the mechanical strength study showed a reduction on the degree of polymerization from 1100 to 850 after 4 days of drying. The dielectric analysis of the samples showed different behavior in one of the solids evaluated and it was also found a decreased hygroscopic capacity of degraded samples in comparison with new samples.

Summary:This study was undertaken to analyse the relationship between total calcium (TCa) and ionized calcium (ICa) in patients with cancer, and to assess the clinical value of routine measurements of ICa in these patients. Serum TCa, ICa, albumin, proteins and creatinine were measured in 188 adult patients with solid malignant tumours. Most of them were out-patients, the Karnofsky score being 80 or above in 67%. The correlation coefficient between ICa and TCa was 0.85 (P < 0.001) and did not improve after correcting TCa for protein concentration with several published formulae. Although TCa measurements had a global diagnostic accuracy (percent of patients correctly classified) of 90%, they failed to identify a substantial proportion of patients with increased levels of ICa (57% for uncorrected TCa, and 27-57% for protein-corrected TCa). However, the finding of slightly increased ICa levels did not seem to predict the development of frank hypercalcaemia and did not impair the prognosis. According to these results, the routine measurement of ICa in unselected patients with cancer has no clinical usefulness.