absorbance

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absorbance

 [ab-sor´bans]
in radiology, a measure of the ability of a medium to absorb radiation, expressed as the logarithm of the quotient of the intensity of the radiation entering the medium divided by that leaving it.

ab·sor·bance (A, A),

(ab-sōr'bants),
spectrophotometry log of the ratio of the radiant power of the incident radiation to the radiant power of the transmitted radiation.

absorbance

/ab·sor·bance/ (-sor´bans)
1. in analytical chemistry, a measure of the light that a solution does not transmit compared to a pure solution. Symbol .
2. in radiology, a measure of the ability of a medium to absorb radiation, expressed as the logarithm of the ratio of the intensity of the radiation entering the medium to that leaving it.

absorbance

[əbsôr′bəns]
the degree of absorption of light or other radiant energy by a medium exposed to the energy. It is expressed as the logarithm of the ratio of energy transmitted through a vacuum to the energy transmitted through the medium. For solutions, it is the logarithm of the ratio of energy transmitted through pure solvent to the energy transmitted through the solution. Absorbance varies with factors such as wavelength, solution concentration, and path length.

Absorbance

Chemistry A logarithm of the percent transmission of a wavelength of light through a liquid. 
Microbiology A measure of the amount of light absorbed by a suspension of bacteria or an organic solution, measured by spectrophotometry. Absorbance values are used to plot the growth of bacteria in broth and gauge the purity and concentration of molecules in solution.

ab·sor·bance

(ăb-sōr'băns)
spectrophotometry 2 minus the log of the percentage transmittance of light.
Synonym(s): extinction (2) , optic density.

absorbance

a spectrophotometric measurement of the light absorbed by a solution at a particular WAVELENGTH. The absorbance (A) derives from the percentage of light transmitted as follows:

where Io is the incident light intensity and I is the transmitted light intensity. The absorbance is related to the molar absorption coefficient (extinction coefficient) e (cm-1M-1), concentration c (M), and path length l (cm) as follows:

Absorbance can therefore be used to determine the concentration of a substance in solution, to follow conversion of a SUBSTRATE to a product in an enzymic reaction (see ENZYME), and so on.

Absorbance is sometimes referred to as OPTICAL DENSITY, although this term should be used for measurement of light scattering.

absorbance 

A measure of absorption equal to the logarithm to the base 10 of the reciprocal of the transmittance T, for a specified wavelength and expressed as A = −log10 T. Syn. optical density. See optical density; transmittance.

absorbance

in radiology, a measure of the ability of a medium to absorb radiation, expressed as the logarithm of the quotient of the intensity of the radiation entering the medium divided by that leaving it.
References in periodicals archive ?
With the increase of concentration, the decrease of absorbance value and the calculated percentage inhibition has shown with the help of tables.
1) reminds us of the difficulty of assessing amniotic fluid bilirubin absorbance in specimens contaminated by blood.
3, it is obvious that in vulcanization of 312-DCP with an increase of allyl absorbances, a decrease of swelling occurs, which means that the coagent participates more in crosslinking than in grafting and cyclization.
The first overtone C - H peaks in the 1600 to 1850 nm range have very high absorbances, with virtually no light reaching the detector.
These patients displayed reaction monitors similar to those for the index patient, demonstrating a highly increased baseline absorbance after the addition of reagent 1 (patient 2 in Fig.
NIR absorbance spectra of these samples from 1100 nm to 2500 nm were measured using a commercial spectrometer (NIR Systems model 6500).
Therefore, the higher absorbance of the extracts proves a higher antioxidant activity.
Addition of the hemoglobins changed the absorbance values at 365 and 550 nm, and those changes affect what is calculated as the AF background turbidity.
A new generation of PLA plates is currently being molded with an improved PLA formulation and a reduced absorbance to minimize plate background and to enhance the dynamic range.
001) higher mean absorbances were detected in patients not on a GFD; however, the same effect was observed only for IgG isotype among CD patients on a GFD.
Detection and quantification of the blood pigments from the absorbance spectra are, however, difficult, and attempts to quantify these pigments (1, 10, 11) were not very successful because of factors such as turbidity, pH variability (11), and the large overlap of the absorbance curves, especially those of oxyhemoglobin and methemoglobin (1, 2, 12).
For the EIA assay, the reflex is not necessary for specimens with an absorbance >1.