The long-standing model of pigment cell origins is implicitly based upon a progressive fate restriction model of neural crest development and postulates the existence of a partially restricted progenitor common to all pigment cell types (i.e., a chromatoblast) [38] .
Sodium is the fourth most abundant element on earth, comprising about 2.6% of the earth's crust; it is the most abundant of the alkali group of metals. It is now obtained commercially by the electrolysis of absolutely dry fused sodium chloride.
Sodium is a reactive metal. It reacts with Oxygen in the air and produces a layer of oxide-Sodium Oxide. Sodium Oxide is like rust for Sodium, which corrodes the metal.Sodium is heated in the absence of Oxygen in a glass enclosure to make street lamps. When a mass of heated Sodium reacts with Oxygen the whole thing turns into white Sodium Oxide.t reacts with Oxygen in the air and produces a layer of oxide-Sodium Oxide. Sodium Oxide is like rust for Sodium, which corrodes the metal. Sodium is heated in the absence of Oxygen in a glass enclosure to make street lamps.