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Countercurrent exchange is a key concept in chemical engineering thermodynamics and manufacturing processes, for example in extracting sucrose from sugar beet roots. Countercurrent multiplication is a similar but different concept where liquid moves in a loop followed by a long length of movement in opposite directions with an intermediate zone.
The rete mirabile utilizes countercurrent blood flow within the net (blood flowing in opposite directions) to act as a countercurrent exchanger. It exchanges heat, ions, or gases between vessel walls so that the two bloodstreams within the rete maintain a gradient with respect to temperature, or concentration of gases or solutes.
Two early examples of synthetic biological circuits were published in Nature in 2000. One, by Tim Gardner, Charles Cantor, and Jim Collins working at Boston University, demonstrated a "bistable" switch in E. coli. The switch is turned on by heating the culture of bacteria and turned off by addition of IPTG.
English: The exchange of heat in this diagram (1) is an example of countercurrent exchange. In this example the cold water requires the birds circulatory system to recycle heat and minimize heat loss through the skin. The warm arterial blood (2) flowing away from the heart warms up the cooler venous blood (3) heading towards the heart.
All chromatographic purifications and separations which are executed via solvent gradient batch chromatography can be performed using MCSGP. Typical examples are reversed phase purification of peptides, hydrophobic interaction chromatography for fatty acids or for example ion exchange chromatography of proteins or antibodies. The process can ...
The counter current design is the most efficient, in that it can transfer the most heat from the heat (transfer) medium per unit mass due to the fact that the average temperature difference along any unit length is higher. See countercurrent exchange.
A countercurrent mechanism system is a mechanism that expends energy to create a concentration gradient. It is found widely in nature and especially in mammalian organs. For example, it can refer to the process that is underlying the process of urine concentration, that is, the production of hyperosmotic urine by the mammalian kidney .
Countercurrent distribution, therefore, is a method of using a series of vessels (separatory funnels) to separate compounds by a sequence of liquid-liquid extraction operations. Contrary to liquid-liquid extraction, in the CCD instruments the upper phase is decanted from the lower phase once the phases have settled.