Zirconium dioxide for aesthetic reasons, or of 2) strong, extremely durable dental prostheses constructed entirely from monolithic zirconia, with limited but constantly improving aesthetics. Zirconia stabilized with yttria (yttrium oxide), known as yttria-stabilized zirconia, can be used as a strong base material in some full ceramic crown restorations. Transformation toughened zirconia is used to make ceramic knives. Because of the hardness, ceramic-edged cutlery stays sharp longer than steel edged products. Due to its infusibility and brilliant luminosity when incandescent, it was used as an ingredient of sticks for limelight. Zirconia has been proposed to electrolyze carbon monoxide and oxygen from the atmosphere
Synthetic cannabinoids were originally used for cannabinoid research focusing on tetrahydrocannabinol (THC), the main psychoactive and analgesic compound found in the cannabis plant. Synthetic cannabinoids were used in part due to legal restrictions on natural cannabinoids, which make them very hard to obtain for research. Tritium-labelled cannabinoids such as CP-55,940 were instrumental in discovering the cannabinoid receptors in the early 1990s. Some early synthetic cannabinoids were also used in clinics. Nabilone, a first generation synthetic THC analog, has been used as an antiemetic, a drug to combat vomiting and nausea, since 1981. Synthetic THC (marinol, dronabinol) has been used as an antiemetic