Period 6 element devices though concerns about the element's toxicity have led to mercury thermometers and sphygmomanometers being largely phased out in clinical environments in favor of alcohol-filled, galinstan-filled, digital, or thermistor-based instruments. It remains in use in scientific research applications and in amalgam material for dental restoration. It is used in lighting: electricity passed through mercury vapor in a phosphor tube produces short-wave ultraviolet light which then causes the phosphor to fluoresce, making visible light. Thallium is a chemical element with the symbol Tl and atomic number 81. This soft gray other metal resembles tin but discolors when exposed to air. The
Sn-glycerol-1-phosphate dehydrogenase encoding glycerol-1-phosphate dehydrogenase has been detected in all the archaeal species and has not been found in any bacterial or eukaryal species. "sn"-glycerol 1-phosphate produced by this enzyme is the most fundamental difference by which Archaea and bacteria are discriminated. Sn-glycerol-1-phosphate dehydrogenase In enzymology, a "sn"-glycerol-1-phosphate dehydrogenase () is an enzyme that catalyzes the chemical reaction The 3 substrates of this enzyme are sn-glycerol 1-phosphate, NAD, and NADP, whereas its 4 products are glycerone phosphate, NADH, NADPH, and H. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD or NADP