A reappraisal was made of the relationship between exposure to atomic radiation in 1945 and the occurrence of salivary gland tumors in heavily exposed survivors. This was made possible by the discovery of 8 additional patients; the total now reported consists of 30 cases. In those exposed to 300+ rads, the number of cases was significantly (p < .01) greater than expected. This was found for the combined group and for malignant types, but not for histologically benign tumors. Our prior conclusion regarding the high‐dose radiation effect upon salivary gland neoplasia remains unchanged in the reanalysis; however, our suggestion that younger persons were at significantly greater risk is weakened.

A pathological investigation was undertaken in Hiroshima on cases seen between 1945 and 1971 to determine the relationship between salivary gland tumors and exposure to atomic (A) bomb radiation. Of the 208 cases of histologically confirmed salivary gland tumors, 62 were A‐bomb survivors and 146 were nonexposed. The relative risk based on the rate in the nonexposed for malignant tumors of salivary glands among the exposed in Hiroshima Prefecture was 11.0, while that of the submaxillary gland was 13.8 and that of the parotid gland was 9.8. They were all highly significant by X2 test (P < 0.001). The latent period of malignant salivary gland tumors was shorter in the exposed than in the nonexposed. Four cases of benign salivary gland tumor, all being benign mixed tumors of the parotid gland, were observed in children whose parents had been exposed. The incidence of mixed tumors of the salivary gland among the exposed in Hiroshima City was 2.0 times higher than that among the nonexposed and showed a tendency to increase with proximity to the hypocenter (P < 0.01). Cancer 52:377‐385, 1983.

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SynopsisIn the research of a continuous ironmaking process from reduced iron, or pre-reduced iron ore, the reduction rate of iron oxide in molten slag by carbon in molten iron was investigated to know the optimum condition. Mixture consisted of, mainly, 40g master slag and 17.1 g iron oxide, was added onto the molten iron in a graphite crucible, the molten copper in a graphite crucible, or the molten iron in an almina crucible to measure the amount of CO gas evolved in the range of 1320 N 1 620 °C. The following results were obtained:(1) The reduction rate of iron oxide in molten slag by carbon in molten iron, or graphite was proportional to the second power of the iron oxide content in the molten slag except for the starting and the ending periods of the experiment.(2) The rate contant and the apparent activation energy of the reduction of iron oxide in molten slag by carbon in molten iron were obtained from the data of the experiment with a graphite crucible-molten iron and a graphite crucible-molten copper.(3) The maximum rate constant of the reduction of iron oxide in molten slag by carbon in molten iron, or graphite was observed around CaO/Si02 =1.5 of molten slag.