# Involution

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Related to Involution: involution of uterus

## involution

[‚in·və′lü·shən]
(biology)
A turning or rolling in.
(embryology)
Gastrulation by ingrowth of blastomeres around the dorsal lip.
(mathematics)
Any transformation that is its own inverse.
In particular, a correspondence between the points on a line that is its own inverse, given algebraically by x ′ = (ax + b)/(cx-a), where a 2+ bc ≠ 0.
A correspondence between the lines passing through a given point on a plane such that corresponding lines pass through corresponding points of an involution of points on a line.
(medicine)
The retrogressive change to their normal condition that organs undergo after fulfilling their functional purposes, as the uterus after pregnancy.
The period of regression or the processes of decline or decay which occur in the human constitution after middle life.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

## Involution

(raising to a power), an algebraic operation consisting in repeating a quantity a n number of times:

The number a is the base of the power, n is the exponent, and an is the power. For example, 3x3x3x3 = 34 = 81. The second power of a number is called its square and the third power, its cube.

## Involution

(regression), in biology, a reduction or loss, in the process of evolution, of certain organs, and a simplification of their organization and functions (for example, various degrees of intestinal reduction in certain parasitic worms and arthropods). Degenerative changes in protozoans and bacteria caused by unfavorable conditions in the habitat are also called involutional. In medicine, the term sometimes refers to atrophy of organs and tissues, such as in aging.

References in periodicals archive ?
Using transrectal ultrasonography (Atoka 500 with a 5 MHz linear probe, Atoka, Wallingford, CT) were performed on days 10, 18 and 30 postpartum evaluations to determine uterine involution and return of cyclic luteal activity.
The effect of oxytocin and pgf2alpha on the uterine involution and pregnancy rates in postpartum arabian mares.
The uterine involution was well and there was no luminal abnormality in the ultrasonographic examinations performed at postpartum 30th d.
The well-posedness of direct and inverse problems for parabolic equations with involution was considered in [3-5].
Let (M, T) be an involution fixing two odd dimensional copies of [K.sub.d][P.sub.n], with normal bundles [eta] and [mu].
Completion of treatment was defined as either 6 months of treatment or full involution (Whichever was earlier).
And professional deformation signifies evolution (specialization in a narrow field), and involution (incapability of doing things in another field).
Tiens-moi au courant, je te prie, de Involution de ces tractations.
Most of them report on the normal involution period of 6 weeks following labour after normal or pathological delivery, without addressing the differences in parity [1-8].
The entire process of thymus organogenesis, maturation, and age-related involution is tightly regulated by transcription factors (TFs) [7], which, in turn, could be regulated at posttranscriptional level by miRNA genes [8, 9].

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