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.
Serum creatinine ranges in adult men run from about 0.6-1.2 mg/dL, and for women the range is around 0.4-1.0. So, it sounds like your creatinine level is within normal limits. A normal BUN:Creatinine ratio is considered to be 10:1-20:1.