Time to first positive test. Drug metabolites take time to reach the urine. A user who is clean beforehand can test negative for over 1 - 4 hours before turning positive at 50 ng/ml, as shown in the following data from Huestis [02] . This is similar to the period of impairment after smoking.
In organic chemistry, transesterification is the process of exchanging the alkoxy group of an ester compound by another alcohol. These reactions are often catalyzed by the addition of an acid or base-Source.Transesterification: a reversible reaction in which one ester is converted into another (as by interchange of ester groups with an alcohol in the presence of a base).The main reaction for converting oil to biodiesel is called transesterification.n organic chemistry, transesterification is the process of exchanging the alkoxy group of an ester compound by another alcohol. These reactions are often catalyzed by the addition of an acid or base-Source.
Transgender, transsexual, transvestite. A transvestite is a person who dresses in a style or manner traditionally associated with the opposite sex. At the root of the word is the Latin vestire, meaning to dress. Transsexual means one who wishes to be considered by society as a member of the opposite biological sex. Some transsexuals undergo sex change operations, and some do not. Transgender is a more general term that includes transvestites, transsexuals, and anyone else who does not conform to typical gender roles.