Osmium (from Greek á½ÏÎ¼Î® osme, smell) is a chemical element with symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element, with a density of 7004225900000000000â 22.59 g/cm3. Its alloys with platinum, iridium, and other platinum-group metals are employed in fountain pen nibs, electrical contacts, and other applications where extreme durability and hardness are needed.
Goiter is a noncancerous enlargement of the thyroid gland. The most common cause of goiter worldwide is iodine deficiency in the diet. Goiter is often caused by (and a symptom of) hyperthyroidism in the United States, where iodized salt provides plenty of iodine.
Also, some goiters are associated with normal levels of thyroid hormones. Both inflammation and tumors can cause thyroid enlargement. Sometimes, the entire gland may be enlarged in a symmetrical pattern, while in other goiters, nodules, or enlargement may develop in one part of the gland only.