Scanning Electron Microscope (SEM)
The basic principle is that a beam of electrons is generated by a suitable source, typically a tungsten filament or a field emission gun.
The electron beam is accelerated through a high voltage and pass through a system of apertures and electromagnetic lenses to produce a thin beam of electrons.
Then the beam scams the surface of the specimen. Electrons
are emitted from the specimen by the action of the scanning
beam and collected by a suitably-positioned detector.
Advantages Of SEM:-
Advantages of a Scanning Electron Microscope include its wide -array applications, the detailed three-dimensional and topographical imaging and the versatile information garnered from different detectors.
SEMS are also easy to operate with the proper training and advances in computer technology and associated software make operation user-friendly.
Although all samples must be prepared before placed in the vaccume chamber, most SEM samples require minimal preparation actions.
Disadvantages of SEM :-
The disadvantages of a SEM start with the size and cost. SEMs are expensive, large and must be housed in an area free of any possible electric, magnetic or vibration interference.
Maintenance involves keeping a steady voltage, currents to
electromagnetic coils and circulation of cool water.
SEMS are limited to solid, inorganic samples small enough to fit inside the vaccume chamber that can handle moderate vaccume pressure.
Application Of SEM :-
SEMs have a variety of application in a no. of scientific and industry-related field, especially where characterizations of solid materials is beneficial.
SEMS can be essential research tool in field such as life science ,biology, medical and forensic science etc..
In addition, SEMs have practical industrial and technological applications such as semiconductor inspection, production line of miniscule products and assembly of microchips for computers.
Docking
Molecular docking can be defined as the binding of a small molecule called ligand, on to a specific site in a larger molecule. Docking is the computational determination of binding affinity between molecules (protein structure and ligand).
Importance Of Docking :-
It is the key to rational drug design.
The results of docking can be used to find inhibitors for specific target proteins and thus to design new drugs.
It is gaining importance as the number of proteins whose structure is known increases. Identification of the ligand's correct binding geometry in the binding site.
Signal transduction..
Application Of Docking:-
Molecular docking is frequently used in the process of computer aided drug design (CADD).
It can be applied in different stages of the drug design process's in order to -
1- Pridict the binding mode of already known ligands.
2- Identify novel and potent ligands.
3- As a binding affinity predictive tool.
4- Virtual screening (hit identification).
5- Drug discovery (lead optimization).
6- Bioremediation. (Protein ligand docking can also be used to predict pollutants that can be degraded by enzymes.)
7- Protein-Protein docking. 8- Chemical mechanism studies.
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