1 Routine screening of average-risk women should begin at age 50, instead of age 40. 2  Routine screening should end at age 74. 3  Women should get screening mammograms every two years instead of every year.4  Breast self-exams have little value, based on findings from several large studies. Routine screening of average-risk women should begin at age 50, instead of age 40. 2  Routine screening should end at age 74. 3  Women should get screening mammograms every two years instead of every year.
in chemical compound: Alkynes. Molecules that contain a triple bond between two carbon atoms are known as alkynes. The triple bond is made up of one Ï bond and two Ï bonds. As in alkenes, the Ï bonds constitute regions of increased electron density lying parallel to the carbon-carbon bond axis.
An alkyd is a polyester modified by the addition of fatty acids and other components. They are derived from polyols and a dicarboxylic acid or carboxylic acid anhydride. The term alkyd is a modification of the original name alcid, reflecting the fact that they are derived from alc ohol and organic ac id s. The inclusion of the fatty acid confers a tendency to form flexible coating. Alkyds are used in paints and in moulds for casting.