With more education and experience, accountants can become certified. Some financial documents, such as those submitted to the Securities and Exchange Commission, must be signed by a Certified Public Accountant.
Hyperchromicity is the increase of absorbance (optical density) of a material. The most famous example is the hyperchromicity of DNA that occurs when the DNA duplex is denatured. The UV absorption is increased when the two single DNA strands are being separated, either by heat or by addition of denaturant or by increasing the pH level.
A renaturation experiment with the temperature jump apparatus. The absorbance at 260 rnp of a solution of T4 DNA as a function of time was measured. A, = 1.02. The alkali-denatured DNA was rapidly heated from 0 to (T,-25%) and kept at 67% while the DNA renatured.The temperature was then slowly raised to lOOâC, the DNA melted, the temperature was lowered as rapidly as possible to (T,-25%) and maintained constant., = 1.02. The alkali-denatured DNA was rapidly heated from 0 to (T,-25%) and kept at 67% while the DNA renatured. The temperature was then slowly raised to lOOâC, the DNA melted, the temperature was lowered as rapidly as possible to (T,-25%) and maintained constant. The DNA again renatured with the same rate.