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.
DHEA is a precursor to female sex hormones estrogen, progesterone and testosterone. It is often called the âmother hormoneâ because it is the source that fuels the bodyâs metabolic pathway. Like most hormones, women have optimal DHEA levels in their 20s. After that, DHEA levels slowly decline with aging. There is an 80% decline in DHEA by the age of 70. Age-related decline of DHEA is inevitable, but the decline in DHEA associated with chronic stress and adrenal fatigue is not. Women who are chronically stressed exhaust their adrenal glands, which results in low cortisol and low DHEA levels. Prevention and/or treatment of adrenal fatigue will prevent this.