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Bioconcentration. In aquatic toxicology, bioconcentration is the accumulation of a water-borne chemical substance in an organism exposed to the water. [1][2] There are several ways in which to measure and assess bioaccumulation and bioconcentration. These include: octanol-water partition coefficients (K OW), bioconcentration factors (BCF ...
Tris (pentafluorophenyl)borane, sometimes referred to as "BCF", is the chemical compound (C6F5)3B. It is a white, volatile solid. The molecule consists of three pentafluorophenyl groups attached in a "paddle-wheel" manner to a central boron atom; the BC3 core is planar. It has been described as the “ideal Lewis acid ” because of its high ...
Bromochlorodifluoromethane (BCF), also referred to by the code numbers Halon 1211 and Freon 12B1, is a haloalkane with the chemical formula C F 2 Cl Br. It is used for fire suppression, especially for expensive equipment or items that could be damaged by the residue from other types of extinguishers. [ 1 ]
Cunningham numbers of the form b n − 1 can only be prime if b = 2 and n is prime, assuming that n ≥ 2; these are the Mersenne numbers. Numbers of the form b n + 1 can only be prime if b is even and n is a power of 2 , again assuming n ≥ 2; these are the generalized Fermat numbers, which are Fermat numbers when b = 2.
The Hayflick limit, or Hayflick phenomenon, is the number of times a normal somatic, differentiated human cell population will divide before cell division stops. [ 1 ] [ 2 ] The concept of the Hayflick limit was advanced by American anatomist Leonard Hayflick in 1961, [ 3 ] at the Wistar Institute in Philadelphia , Pennsylvania.
Survival analysis is a branch of statistics for analyzing the expected duration of time until one event occurs, such as death in biological organisms and failure in mechanical systems. This topic is called reliability theory, reliability analysis or reliability engineering in engineering, duration analysis or duration modelling in economics ...
Gutmann, a chemist renowned for his work on non-aqueous solvents, described an acceptor-number scale for solvent Lewis acidity [4] with two reference points relating to the 31 P NMR chemical shift of Et 3 PO in the weakly Lewis acidic solvent hexane (δ = 41.0 ppm, AN 0) and in the strongly Lewis acidic solvent SbCl 5 (δ = 86.1 ppm, AN 100).
A measure of the state of health of a person or group in which the benefits, in terms of length of life, are adjusted to reflect the quality of life. One quality-adjusted life year (QALY) is equal to 1 year of life in perfect health. [4] It combines two different benefits of treatment—length of life and quality of life—into a single number ...