Ethanol or isopropanol has been suggested[45,46] for the storage of tissues for DNA extraction. Tissues stored in ethanol have been reported to yield highly degraded DNA fragments;[44,47] however, much of this degradation appears to occur during the extraction procedure rather than during storage. For short-term storage of up to 1 year, 70% ethanol appears to function as well as 100% ethanol; however, 100% ethanol is recommended for storage exceeding 2 years. Other organic solvents have been examined for DNA preservability of insects and their intracellular symbiotic bacteria. At room temperature for 6 months of storage, acetone, diethyl ether, and ethyl acetate were as efficient as ethanol or isopropanol at DNA preservation, whereas chloroform and methanol were poor preservatives.1-49-1 In addition, acetone was found to be more robust against water contamination than ethanol and may prove to be a better storage solution than ethanol.
Genomic DNA in dried blood spots on filter paper or other media (i.e., Guthrie cards or FTA® cards) stored at room temperature is reported to be stable for at least 7.5 years. This method of tissue storage is widely used in human genetic studies; however, some degradation has been reported.[44,52] The utility of this method of storage has proven effective and recent advancements allow direct PCR amplification without DNA extraction.
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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.