Fetal bovine serum specific cell type. When changing from batch to batch it is usual to adapt the cells to the new batch of material, for example, by mixing 50% of the old serum with 50% of the new serum and allowing the cells to acclimatise to the new material. Serum is stored frozen to preserve the stability of components such as growth factors. When serum is thawed, some precipitation may be seen. This is a normal phenomenon and it does not compromise the quality of serum in any way. The precipitate may be removed by transferring the serum to sterile tubes and
Sweat gland except the lips, ear canal, prepuce, glans penis, labia minora, and clitoris. They are ten times smaller than apocrine sweat glands, do not extend as deeply into the dermis, and excrete directly onto the surface of the skin. The proportion of eccrine glands decreases with age. The clear secretion produced by eccrine sweat glands is termed sweat or "sensible perspiration". Sweat is mostly water, but it does contain some electrolytes, since it is derived from blood plasma. The presence of sodium chloride gives sweat a salty taste. The total volume of sweat produced depends on the number of functional glands