MyokineA myokine is one of several hundred cytokines or other small proteins (~5–20 kDa) and proteoglycan peptides that are produced and released by skeletal muscle cells (muscle fibers) in response to muscular contractions. They have autocrine, paracrine and/or endocrine effects; their systemic effects occur at picomolar concentrations. Receptors for myokines are found on muscle, fat, liver, pancreas, bone, heart, immune, and brain cells. The location of these receptors reflects the fact that myokines have multiple functions.
Spatiotemporal gene expressionSpatiotemporal gene expression is the activation of genes within specific tissues of an organism at specific times during development. Gene activation patterns vary widely in complexity. Some are straightforward and static, such as the pattern of tubulin, which is expressed in all cells at all times in life. Some, on the other hand, are extraordinarily intricate and difficult to predict and model, with expression fluctuating wildly from minute to minute or from cell to cell.
Neurotrophin-3Neurotrophin-3 is a protein that in humans is encoded by the NTF3 gene. The protein encoded by this gene, NT-3, is a neurotrophic factor in the NGF (Nerve Growth Factor) family of neurotrophins. It is a protein growth factor which has activity on certain neurons of the peripheral and central nervous system; it helps to support the survival and differentiation of existing neurons, and encourages the growth and differentiation of new neurons and synapses.
Problem of inductionFirst formulated by David Hume, the problem of induction questions our reasons for believing that the future will resemble the past, or more broadly it questions predictions about unobserved things based on previous observations. This inference from the observed to the unobserved is known as "inductive inferences", and Hume, while acknowledging that everyone does and must make such inferences, argued that there is no non-circular way to justify them, thereby undermining one of the Enlightenment pillars of rationality.
