Incidence of thyroid carcinoma has increased dramatically; however, simultaneous occurrence of different tumors in a single thyroid gland is rare and the embryologic or molecular explanations for such cases lack a solid basis. We report on a 67-year-old woman who underwent surgery for cytologically undetermined nodules in the bilateral thyroid glands. Postoperative pathology findings indicated synchronous occurrence of discrete papillary, follicular, and medullary thyroid carcinoma. She has remained disease-free after postoperative radioactive iodine therapy (130 mCi). This is the fifth report on the synchronous occurrence of different tumors in a single thyroid gland worldwide, and the first ever in Asia.

Recently, Stainless steels have been increasingly selected as the fitting or the valve materials of water pipes as the human health issue is getting higher and higher. Therefore, the connectors attached at pipes to deliver water are exposed to more severe environments than the pipes because crevice or galvanic corrosion is apt to occur at the fittings or the valves. Effects of the solid solution annealing, cooling rate after this heat treatment, and passivation on the corrosion properties of the shell mold casted SSC13 (STS304 alloy equivalent) were studied. The heating and quenching treatment more or less reduced hardness but effectively improved corrosion resistance. It was explained by the reduction of delta ferrite contents. Independent of heat treatment, the chemical passivation treatment also lowered corrosion rate but the improvement of corrosion resistance depended on temperature and time for passivation treatment indicating that the optimum conditions for passivation treatment were the bath temperature of 34 o C and operating time of 10 minutes. Therefore it is suggested that the corrosion resistance of SSC13 can be effectively improved with the heat treatment, where SSC13 is heated for 10 minutes at 1120 °C and quenched and passivation treatment, where SSC13 is passivated for at least 10 seconds at 34 °C nitric acid solution.

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