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Stem cells undergo cell proliferation to produce proliferating "transit amplifying" daughter cells that later differentiate to construct tissues during normal development and tissue growth, during tissue regeneration after damage, or in cancer.
The 12 E. coli LTEE populations on June 25, 2008. [1]The E. coli long-term evolution experiment (LTEE) is an ongoing study in experimental evolution begun by Richard Lenski at the University of California, Irvine, carried on by Lenski and colleagues at Michigan State University, [2] and currently overseen by Jeffrey Barrick at the University of Texas at Austin. [3]
In humans with non-injured tissues, the tissue naturally regenerates over time; by default, new available cells replace expended cells. For example, the body regenerates a full bone within ten years, while non-injured skin tissue is regenerated within two weeks. [2] With injured tissue, the body usually has a different response.
Experiments in Wallerian degeneration have shown that upon injury oligodendrocytes either undergo programmed cell death or enter a state of rest. Therefore, unlike Schwann cells, oligodendrocytes fail to clean up the myelin sheaths and their debris.
For example, my partial molar pregnancy caused me to develop atypical placental site nodules (APSN) — which my OB-GYN and Dr. Liu knew needed further, serious investigation.
The capacity for natural transformation appears to occur in a number of prokaryotes, and thus far 67 prokaryotic species (in seven different phyla) are known to undergo this process. [ 19 ] Competence for transformation is typically induced by high cell density and/or nutritional limitation, conditions associated with the stationary phase of ...
The opposite and much more common type of behaviour, in which fluids become less viscous the longer they undergo shear, is called thixotropy. Examples of rheopectic fluids include gypsum pastes, printer inks, and synovial fluid. [2] There is ongoing research into new ways to make and use rheopectic materials.
An example is the natural decay of potassium-40 to argon-40, which forms most of the argon in the air. Also on Earth, natural transmutations from the different mechanisms of natural nuclear reactions occur, due to cosmic ray bombardment of elements (for example, to form carbon-14 ), and also occasionally from natural neutron bombardment (for ...