11. The isotactic polymer can be produced from optically active propylene oxide, but at a high cost. 12. Therefore, a necessary condition for upconverting systems is the existence of optically active long-lived excited states. 13. Nicotine is optically active , having two enantiomeric forms. 14. Since they affect chirality, they produce optically active products from optically inactive or mixed starting materials. 15. Using this method, optically active carboxylic acids and optically active carboxylic acid esters can be obtained. 16. Sounding like homework : so the complex may or may not be optically active , but the ligand is? 17. His research focused predominantly on carbohydrate chemistry in which he confirmed a number of structures of optically active sugars. 18. A ring can be constructed with other optically active materials that are able to conduct a beam with low losses. 19. It is a mixture of the two optically active isomers of 12 ( " Z " ) 9, 10-epoxy-octadecenoic acid. 20. Igor researchers optically active defects in solids, with an overarching goal to identify new generation of solid state quantum emitters.