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Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms. [1]
Van Krevelen diagram for various solid fuels. Van Krevelen diagrams are graphical plots developed by Dirk Willem van Krevelen (chemist and professor of fuel technology at the TU Delft) and used to assess the origin and maturity of kerogen and petroleum.
The vibration theory of smell proposes that a molecule's smell character is due to its vibrational frequency in the infrared range. This controversial theory is an alternative to the more widely accepted docking theory of olfaction (formerly termed the shape theory of olfaction), which proposes that a molecule's smell character is due to a range of weak non-covalent interactions between its ...
Nonoxynol-9 is a common ingredient of most vaginal and anal lubricants due to its spermicidal properties. A 2004 study found that over a six-month period, the typical-use failure rates for five nonoxynol-9 vaginal contraceptives (film, suppository, and gels at three different concentrations) ranged from 10% to 20%.
Of the group 9 elements, only cobalt has a biological role. It is a key constituent of cobalamin, also known as vitamin B 12, the primary biological reservoir of cobalt as an ultratrace element. [21] [22] Bacteria in the stomachs of ruminant animals convert cobalt salts into vitamin B 12, a compound which can only be produced by bacteria or ...
A scientific theory is an explanation of an aspect of the natural world that can be or that has been repeatedly tested and has corroborating evidence in accordance with the scientific method, using accepted protocols of observation, measurement, and evaluation of results.
A coherent theory of neutral evolution was first proposed by Motoo Kimura in 1968 [9] and by King and Jukes independently in 1969. [10] Kimura initially focused on differences among species; King and Jukes focused on differences within species. Many molecular biologists and population geneticists also contributed to the development of the ...