Harvest Rate Model. In a perfusion-based process, harvest of cell culture fluid begins significantly before cell density or titer has reached a steady state. After inoculation of the bioreactor, cells grow in batch mode until a specific cell density is achieved, at which point perfusion is initiated at a low HR.
Borax (sodium tetraborate hexahydrate or sodium borate) is a naturally-occurring mineral composed of sodium, boron, oxygen and water. It has been used as a remedy for over 4000 years. Most commercially-produced borax is mined from deposits produced by the repeated evaporation of seasonal lakes. It is found in large quantities in the Western United States, in Mediterranean countries, Kazakhstan, and the Tibet region of China. Turkey is one of the largest commercial producers of borates.
Borax is a naturally occurring mineral salt that has been widely used in homemade household cleaning formulas, but in recent years the safety of borax has been questioned. If you use homemade cleaners and want to be sure your formulas are safe, you might consider borax substitutes.