1 Leaf shutters are usually fitted within a lens assembly (central shutter), or more rarely immediately behind (behind-the-lens shutter) or, even more rarely, in front of a lens, and shut off the beam of light where it is narrow. 2  Focal-plane shutters are mounted near the focal plane and move to uncover the film or sensor.
DHEA levels begin to naturally decline by the age of 30. While normal levels for women in their 20s fall between 65 and 380 Âµg/dL, for women in their 30s and 40s, the average normal range is 45 to 270 and 32 to 240 Âµg/dL, respectively.
The terminal half-life of DHEA-S is 7 to 10 hours, which is far longer than that of DHEA, which has a terminal half-life of only 15 to 30 minutes. Elimination. DHEA-S is excreted in the urine via the kidneys. Levels. DHEA and DHEA-S are the most abundant circulating steroids in the body. Plasma levels of DHEA-S are 100 or more times higher than those of DHEA, 5 to 10 times higher than those of cortisol, 100 to 500 times those of testosterone, and 1,000 to 10,000 times higher than those of estradiol. Levels of DHEA and DHEA-S vary throughout life.