Ameloblast showing a disruption in enamel production when the person is born. High fevers in childhood are also an example of bodily stressors causing interruptions in enamel production. Another possible example of this sensitivity (stress response pathway activation) may be the development of dental fluorosis after childhood exposure (between the ages of 2 to 8 years old) to excess fluoride, an elemental agent used to increase enamel hardness and prevent dental caries. Ameloblast Ameloblasts are cells present only during tooth development that deposit tooth enamel, which is the hard outermost layer of the tooth forming the surface of the crown. Each
Active layer in permafrost regions due to the low rate of weathering in the very cold climate. The slow rate of decomposition of organic material means gelisols (permafrost soils) are very important as a sink for carbon dioxide. This carbon dioxide and other greenhouse gases (chiefly methane) forms from the very slow decomposition of the excess organic matter that remains in most gelisols and is mixed down into the pereletok layer during relatively hot summers and below that layer during warmer periods about 5000 to 6000 years ago. This storage of carbon means thawing of permafrost may accelerate global warming - some