Search results
Results from the WOW.Com Content Network
For example, the conversion factor between a mass fraction of 1 ppb and a mole fraction of 1 ppb is about 4.7 for the greenhouse gas CFC-11 in air (Molar mass of CFC-11 / Mean molar mass of air = 137.368 / 28.97 = 4.74). For volume fraction, the suffix "V" or "v" is sometimes appended to the parts-per notation (e.g. ppmV, ppbv, pptv).
Specific activity (symbol a) is the activity per unit mass of a radionuclide and is a physical property of that radionuclide. [ 1 ] [ 2 ] It is usually given in units of becquerel per kilogram (Bq/kg), but another commonly used unit of specific activity is the curie per gram (Ci/g).
In pharmacology, biological activity or pharmacological activity describes the beneficial or adverse effects of a drug on living matter. [1] [2] When a drug is a complex chemical mixture, this activity is exerted by the substance's active ingredient or pharmacophore but can be modified by the other constituents. Among the various properties of ...
Multivitamins nutrition facts label showing that the international unit of, for example, vitamins D and E correspond to different gram values. In pharmacology, the international unit (IU) is a unit of measurement for the effect or biological activity of a substance, for the purpose of easier comparison across similar forms of substances.
Formulation studies then consider such factors as particle size, polymorphism, pH, and solubility, as all of these can influence bioavailability and hence the activity of a drug. The drug must be combined with inactive ingredients by a method that ensures that the quantity of drug present is consistent in each dosage unit e.g. each tablet. The ...
Dosage typically includes information on the number of doses, intervals between administrations, and the overall treatment period. [3] For example, a dosage might be described as "200 mg twice daily for two weeks," where 200 mg represents the individual dose, twice daily indicates the frequency, and two weeks specifies the duration of treatment.
To ensure that the drug taker who has poor absorption is dosed appropriately, the bottom value of the deviation range is employed to represent real bioavailability and to calculate the drug dose needed for the drug taker to achieve systemic concentrations similar to the intravenous formulation. [4]
The metabolic equivalent of task (MET) is the objective measure of the ratio of the rate at which a person expends energy, relative to the mass of that person, while performing some specific physical activity compared to a reference, currently set by convention at an absolute 3.5 mL of oxygen per kg per minute, which is the energy expended when sitting quietly by a reference individual, chosen ...