Death and Renewal

A matter of life and death: self-renewal in stem cells.

If Narcissus could have self-renewed even once on seeing his own reflection, he would have died a happy man. Stem cells, on the other hand, have an enormous capacity for self-renewal; in other words, the ability to replicate and generate more of the same. In adult organisms, stem cells reside in specialized niches within each tissue. They replenish tissue cells that are lost during normal homeo...

Note on Fuzzy Random Renewal Process and Renewal Rewards Process

Recently, Zhao et al. [Fuzzy Optimization and Decision Making (2007) 6, 279-295] characterized the interarrival times as fuzzy random variables and presented a fuzzy random elementary renewal theorem on the limit value of the expected renewal rate of the process in the fuzzy random renewal process. They also depicted both the interarrival times and rewards are depicted as fuzzy random variables...

Self-renewal and differentiation

The adult human heart has limited regenerative capacity and, theref fore, functional restoration of the damaged heart presents a great challenge. Despite the progress achieved in the pharmacological and surgical treatment of degenerative myocardial diseases, they are still considered a major cause of morbidity and mortality in the western world. Repopulation of the damaged heart with cardiomyof...

The renewal of medical education in Iran: progress and challenge

Decline in excision circles requires homeostatic renewal or homeostatic death of naive T cells.

When the TCR is formed in the thymus, fragments of DNA are excised from the T cell progenitor chromosome. These TCR rearrangement excision circles (TRECs) are stable, are not replicated in cell division and are therefore most frequent in naive T cells that have recently left the thymus. During life, the average TREC content of peripheral naive T cells decreases between one and two orders of mag...