Bioinformatics

Applications of the Centrifugal  Feild Flow Franctionation This technique of characterization and separation is more efficient than all other techniques and separates a wide range of particles. The advantage of centrifugal FFF lies in the broad range of samples and high resolution that can be achieved by varying the speed and force applied. It is mostly used for biological separations and some of its applications are as follows: The FFF in Heamatology In 1989 rat lymphocytes were separated by using a new hybrid process coupled with Gravitational FFF and an adhesion mechanism. This experiment was carried out five years after the first publishment about FFF technique by Cladwell. In this new experiment the basic principle of separation is the duality of the relative strengths of adhesion of T and B cells and the hydrodynamic flow forces able to unbind theses cells. A scientist Urbankova used the Gravitational FFF technique and checked the size of RBC and showed that they ...

Centrifugation separation techniques The sedimentation rate of the analyte particles in a suspension is dependent upon following properties: ·          Size of the particle ·          Medium ·          External forces applied Stokes’s law is applicable whenever the centrifugal force of ωr 2 is used to carry out sedimentation. Here ω represents the rotational angular velocity and r is representing the distance from the diameter of the analyte particle to the axis of rotation. dr/dt = 2r 2 p (ρ p - ρ m ) ω 2 r/ 9η In this equation dr/dt is the particle’s velocity; η is the viscosity of the medium, r p is the particle’s radius and (ρ p - ρ m ) difference in the density of the particle and the density of the medium. There are various techniques which involve the use of centrifugal force for the separation of particles based upon their rates of sedimentation. These sub...

Centrifugal field flow fractionation: Centrifugal FFF is basically a new name given to Sedimentation FFF after further developments in it. The specialty of this Centrifugal FFF is that it involves the use of centrifugal force as the externally applied force which is the basic element required in the separation of the analyte particles. Channel used in this technique is in the form of a ring which spins at 4900 rpm.  This technique is effective in the separation, characterization and purification of micron-sized particles of any type of analyte. It allows for the separation of particles with only a 5% difference in size. Mode of elution In Centrifugal or sedimentation FFF the elution is carried out by hyperlayer mode. The other two modes of elution fail to explain that for the particles having the size less than 1 µm the retention ratio increases with the increase in velocity of flow. In other words the transport velocity is variable for the particles whose size i...

Field Flow Fractionation Field flow fraction consists of a wide variety of separation methods for which are used for the purification and characterization of superamolecular compounds like macromolecules, colloids, particles, gels, emulsions and cells. So it has applications especially in the field of biological sciences. It consists of various sub-techniques and separation devices which are used for the separation and characterization of the particles ranging in size from 10-3 to 102 µm.  These sub-techniques of the FFF are capable of separating the particles on the basis of their physical properties like charge, mass, size and density. The basic concept of Filed flow fractionation for the first time was given in 1960s by J. Calvin Giddings. Field flow fractionation is considered to be the hybrid of chromatography, electrophoresis and ultracentrifugation all of which are field-driven methods.  Like ultracentrifugation is requires a field force and like chromat...