|a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.|
|a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question.|
|1.||the act or process of regenerating or the state of being regenerated; rebirth or renewal|
|2.||the regrowth by an animal or plant of an organ, tissue, or part that has been lost or destroyed|
|3.||electronics the use of positive feedback to increase the amplification of a radio frequency stage|
regeneration re·gen·er·a·tion (rĭ-jěn'ə-rā'shən)
Regrowth of lost or destroyed parts or organs.
|regeneration (rĭ-jěn'ə-rā'shən) Pronunciation Key
The regrowth of lost or destroyed parts or organs.
Our Living Language : Regeneration of parts or, in some cases, nearly the entire body of an organism from a part, is more common than one might think. Many protists like the amoeba that have been cut in half can grow back into a complete organism so long as enough of the nuclear material is undamaged. Severed cell parts, such as flagella, can also be regrown in protists. New plants can be grown from cuttings, and plants can often be regenerated from a mass of fully differentiated cells (such as a section of a carrot root), which, if isolated in a suitable environment, turn into a mass of undifferentiated cells that develop into a fully differentiated organism. The capacity for regeneration varies widely in animals, with some able to regenerate whole limbs and others not, but the capacity is reduced significantly in more complex animals. Certain simple invertebrates like the hydra are always regenerating themselves. If cut into tiny pieces that are then mixed up, the pieces can reorganize themselves and grow back into a complete organism. Flatworms have the capacity to regenerate themselves from only a small mass of cells. If they are chopped up into fine pieces, each piece has the capacity to develop into an entire organism. Starfish, which are echinoderms, can regenerate their entire body from their central section and a single arm. Newts and salamanders can regenerate lost legs and parts of eyes, but many other amphibians such as frogs and toads cannot. Certain lizards can regenerate their tails. In many animals, these regenerated body parts are not as large as the originals but are usually sufficient to be functional. Many higher animals such as mammals regularly regenerate certain tissues such as hair and skin and portions of others such as bone, but most tissues cannot be regenerated. About 75 percent of the human liver can be removed, and it will regenerate into a functional organ. The physiological reasons for this are still not understood. Regeneration in this case takes the form of the enlargement of the remaining structures rather than the re-creation of the lost ones. Thus, there are four mechanisms for tissue regeneration in animals: the reorganization of existing cells (as in the hydra), the differentiation of stored stem cells into the specific tissues needed (as in the salamander), the dedifferentiation of neighboring tissue cells and their subsequent regrowth as cells of the needed type (as in plants as well as certain animals like the salamander), and the compensatory growth of the surviving cells of the specific tissue (as in the human liver). There is a great interest in stem cells because of their potential use in regenerating body tissues, such as nerve cells and heart muscle. The biochemical mechanisms for dedifferentiation are also the subject of intense study.
only found in Matt. 19:28 and Titus 3:5. This word literally means a "new birth." The Greek word so rendered (palingenesia) is used by classical writers with reference to the changes produced by the return of spring. In Matt. 19:28 the word is equivalent to the "restitution of all things" (Acts 3:21). In Titus 3:5 it denotes that change of heart elsewhere spoken of as a passing from death to life (1 John 3:14); becoming a new creature in Christ Jesus (2 Cor. 5:17); being born again (John 3:5); a renewal of the mind (Rom. 12:2); a resurrection from the dead (Eph. 2:6); a being quickened (2:1, 5). This change is ascribed to the Holy Spirit. It originates not with man but with God (John 1:12, 13; 1 John 2:29; 5:1, 4). As to the nature of the change, it consists in the implanting of a new principle or disposition in the soul; the impartation of spiritual life to those who are by nature "dead in trespasses and sins." The necessity of such a change is emphatically affirmed in Scripture (John 3:3; Rom. 7:18; 8:7-9; 1 Cor. 2:14; Eph. 2:1; 4:21-24).
in biology, the process by which some organisms replace or restore lost or amputated body parts
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