Polymer Gel Matrix

Capillary gel electrophoresis can be used for separation of small DNA fragments such as nucleotides or small oligonucleotides (10-150 bases in size).[3] For larger

DNA fragments, electrophoresis must be undertaken with a separation matrix such as agarose, polyacrylamide, or a liquid polymer to act as a molecular sieve. For CGE, there are two types of gel matrices in use: relatively high viscosity cross-linked (i.e., chemical) or low viscosity non-cross-linked (i.e., physical). The latter are more flexible, and hence widely used because of the following properties: 1) they can operate at more extreme temperatures, and 2) they are easily replaced by rinsing the capillary, thus minimizing contamination and enhancing convenience. With both types of gel matrices, capillaries that are modified by coating agents can be used to eliminate the EOF.[4]

Commercially produced polymers are available. Liquid polymers made in-house are cheaper but formulation is more likely to vary between batches thereby affecting reproducibility and sensitivity. Although costly, commercial polymers are produced to specific standards and consistent quality, which are important considerations in the DNA diagnostic laboratory.

Products such as glycerol, mannitol, urea, and for-mamide can be added to the sieving media for different purposes. For example, 5% glycerol can be used to preserve secondary structures when SSCP analysis is performed. Formamide is used to keep double-stranded DNA denatured when DNA fragment analysis is required.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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