The International System of Units (abbreviated SI from French: Le Système international d'unités) is the modern form of the metric system and is the world's most widely used system of measurement, used in both everyday commerce and science. It comprises a coherent system of units of measurement built around seven base units, 22 named and an indeterminate number of unnamed coherent derived units, and a set of prefixes that act as decimal-based multipliers.
The standards, published in 1960 as the result of an initiative started in 1948, are based on the metre–kilogram–second (MKS) system, rather than the centimetre–gram–second (CGS) system, which, in turn, had several variants. The SI has been declared to be an evolving system; thus prefixes and units are created and unit definitions are modified through international agreement as the technology of measurement progresses, and as the precision of measurements improves.
The two-liter bottle is a common container for soft drinks. These bottles are produced from polyethylene terephthalate, also known as PET plastic, using the blow molding process. Bottle labels consist of a printed, tight-fitted plastic sleeve. A resealable screw-top allows the contents to be used at various times while retaining carbonation.
In the United States, the two-liter bottle is one of the few cases where a product is sold by a round number of metric units. Since very few other beverages are sold in this exact quantity, the term "two-liter" in American English almost invariably refers to a soft drink bottle. Other common metric sizes for plastic soft drink bottles include 500 milliliters, 1 liter and 3 liters.
Milligram per cent is a traditional yet inappropriate symbol used to denote a unit of measure of concentration. The traditional (and inaccurate) use of the 'mg%' symbol was meant to indicate the mass (in milligrams) of that chemical in 100 milliliters of solution (e.g., blood). The meaning of the symbol 'percent' is 1, therefore the accurate meaning of the notation 'mg%' is 'mg/100', which is a unit of mass, not a concentration. Therefore, for dimensional analysis purposes, when denoting a concentration of mass divided by volume, one should use units such as 'mg/dL' or the International System of Units equivalent.
For example, a plasma ethanol concentration incorrectly denoted as 0.1 mg% can be written as '0.1 mg/dL' (or '1 mg/L', etc.) meaning a mass of 0.1 milligrams of ethyl alcohol per 100 milliliter volume of solution.