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The amount of relaxation which takes place is a function of time, temperature and stress level, thus the actual effect it has on the system is not precisely known, but can be bounded. Stress relaxation describes how polymers relieve stress under constant strain. Because they are viscoelastic, polymers behave in a nonlinear, non-Hookean fashion. [1]
Gel electrophoresis uses a gel as an anticonvective medium or sieving medium during electrophoresis. Gels suppress the thermal convection caused by the application of the electric field and can also serve to maintain the finished separation so that a post-electrophoresis stain can be applied. [ 3 ]
In polymers, testing may be done at elevated temperatures to produce a result in a shorter amount of time than it could be produced at ambient temperatures. Many mechanical properties of polymers have an Arrhenius type relationship with respect to time and temperature (for example, creep, stress relaxation, and tensile properties). If one ...
The stress relaxation modulus () is the ratio of the stress remaining at time after a step strain was applied at time =: = (), which is the time-dependent generalization of Hooke's law . For visco-elastic solids, G ( t ) {\displaystyle G\left(t\right)} converges to the equilibrium shear modulus [ 4 ] G {\displaystyle G} :
Schematic of the evolution of the instantaneous modulus E(t,T) in a static relaxation test. t is the time and T is the temperature. Consider the relaxation modulus E at two temperatures T and T 0 such that T > T 0. At constant strain, the stress relaxes faster at the higher temperature.
Polyacrylamide gel electrophoresis (PAGE) is a technique widely used in biochemistry, forensic chemistry, genetics, molecular biology and biotechnology to separate biological macromolecules, usually proteins or nucleic acids, according to their electrophoretic mobility. Electrophoretic mobility is a function of the length, conformation, and ...
Electrophoresis techniques used in the assessment of DNA damage include alkaline gel electrophoresis and pulsed field gel electrophoresis. For short DNA segments such as 20 to 60 bp double stranded DNA, running them in polyacrylamide gel (PAGE) will give better resolution (native condition). [ 1 ]
A mobility shift assay is electrophoretic separation of a protein–DNA or protein–RNA mixture on a polyacrylamide or agarose gel for a short period (about 1.5-2 hr for a 15- to 20-cm gel). [4] The speed at which different molecules (and combinations thereof) move through the gel is determined by their size and charge, and to a lesser extent ...