1 Therefore, the idea is to use a set of optimum conditions to get the most efficient yield of ammonia and this involves getting a low % yield (e.g. 8% - 15% conversion) but fast. 2  Described below are the conditions to give the most economic production of ammonia.
Causes of Vitiligo. Melanin is the pigment that gives the skin its characteristic color. Vitiligo is caused by a loss of pigment in the skin, due to destruction of pigment-forming cells known as melanocytes. The exact cause of the destruction of these cells is not known. One possible explanation might be that the body's immune system destroys the cells, as in other autoimmune conditions.
Vitiligo is a disease where patches of skin become discolored. About 30% of people with vitiligo also have a family member with it. This means genetics almost certainly has something to do with it. But for reasons I'll get to in a second, there are probably other factors involved too.mmune Cells Gone Wild Causes Vitiligo. You get your skin color because of a pigment called melanin. This pigment is made in certain cells called melanocytes. People with vitiligo have white patches on their skin because their immune system has killed the melanocytes there. No melanocytes, no melanin, white skin.