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 name for several different but similar chemical compounds, of which probably the commonest is sodium decahydrate or sodium borate. They all contain sodium and boron. Borax is toxic enough to kill ants, fleas and cockroaches and other unwanted insect life. Its effects upon the environment are not yet well documented but it can be toxic to aquatic life if too concentrated. It is regarded by the Australian government as a low threat to the environment but a moderate threat to health.