isomers


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Related to isomers: constitutional isomers, Optical isomers

isomers

[ī′səmərz]
compounds that have the same formula but different structures, resulting in different properties.

isomers (ī´sōmurz),

n.pl 1. organic compounds having the same empirical formula–i.e., the same number of the same atoms but different structural formulas and therefore different physical and chemical properties.
n 2. one of several nuclides having the same number of neutrons and protons but capable of existing, for a measurable time, in different quantum states with different energies and radioactive properties. The isomer of higher energy commonly decays to one with lower energy by a process known as isomeric transition.
isomers, optical,
n.pl two isomers whose structures, dextro- and levo-, differ only in a spatial arrangement that makes them mirror images. This occurs only when there is an asymmetric carbon atom–i.e., one attached to four different substituents. The pharmacologic activity often resides very largely in one of the two forms.
isomers, stereo-,
n.pl molecules that differ only in the spatial arrangement of the atoms. This term includes optical isomers.
References in periodicals archive ?
For PFOS, we detected six major branched isomers in dust: 1m-, 3m-, 4m-, 5miso-, and [summation over (term)][m.
As the observed NMR signal is proportional to the amount of ortho-water in the sample[para-water with its spin number of 0 is "NMR silent"], we can track the percentages of ortho and para isomers at any time and any temperature," Mamone explained.
Each fraction was analyzed by GC to determine isomer composition.
8%), containing the isomers cis-9, trans-11 and trans-10, cis-12 at a proportion 1:1, significantly reduced fat content of breast and leg muscles, and liver in meat-type chickens but increased protein contents in leg muscles and liver, although body weight gain, feed intake and feed conversion ratio were not changed in this study.
Based on both dietary and in vitro studies of lipid metabolism, we hypothesized that the 2 isomers of CLA may have differing effects on acyl-CoA oxidase (ACO), 3-hydroxy, 3-methylglutaryl CoA reductase (HMG-R), and apolipoprotein A-I(Apo A-I) gene expression.
Safflorin(TM) is essentially a 40: 60 optimum ratio of the active isomers c-9, t-11 and t-10, c-12 with the enriched t-10, c-12 isomer component regarded as highly effective for supporting the immune system.
CLA labels don't give a breakdown of the isomers, but Tonalin contains equal amounts of the two.
Khanna of Virginia Commonwealth University in Richmond calls the new results "a very important contribution" Besides verifying theoretical predictions, he says, the findings may also help researchers figure out how to select and stabilize isomers with desirable traits for use as nanometer-scale building blocks for novel structures.
Two other chemical groups are attached to this hexagon, but each can attach at two different angles, resulting in four different versions, or optical isomers.
The test which is commonly used for measuring methamphetamine must differentiate between the two isomers and if, when tested, they are not separated, the possibility is that you will come up with a false positive fothe narcotic form of methamphetamine.
The earlier literature assigned the isomers by relative GC retention times (Wigfield and Phelps 1974).