Butyl rubber plugs are mainly polyisobutylene, but the methyl group in polyisobutylene has a large steric hindrance, the molecule thermal movement is not active, so the gas transmission rate is small to medium, synthetic rubber and the number of molecules in the main chain doubled rarely, so and UV resistance, ozone resistance, weather resistance is very good, and heat resistance is also very high

Nucleic acid assays are widely used in clinical diagnostics, bioanalysis, and environmental monitoring, and are important for disease diagnosis and basic research.

Porcelain crowns provide a more natural appearance, but are more likely to chip. Gold crowns are the least expensive, but they are unsightly and can produce negative allergic reactions. Dental crowns can also be made of zirconium. Zirconia crowns offer an excellent natural appearance without uncomfortable side effects.