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
Blood, Sweat & Tears (Blood, Sweat & Tears album) City. The studio had just taken delivery of one of the first of the model MM-1000 16-track tape recorders, built by Ampex. The new technology allowed for far more flexibility in overdubbing and mixing than the 4 and 8-track tape recorders which were standard in 1968. The album was among the very first 16-track recordings released to the public. An additional song, "Children of the Wind" was recorded for the album but was not included. It later appeared on the compilation, "The Very Best of Blood, Sweat and Tears: What Goes Up!" The album was selected for the 2006 book