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 unsaturated hydrocarbon is a hydrocarbon containing at least one double or triple bond. An alkene is a hydrocarbon containing double bonds. The general formula of an alkene is CnH2n. An alkyne is a hydrocarbon containing triple bonds. The general formula of an alkyne is CnH2n-2.The term saturated is used to refer to a compound in which all carbon-carbon bonds are single bonds and every carbon atom is connected to a different atom.n alkene is a hydrocarbon containing double bonds. The general formula of an alkene is CnH2n. An alkyne is a hydrocarbon containing triple bonds. The general formula of an alkyne is CnH2n-2.