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.
What is the normal level of BUN? Normal BUN levels differ with age and gender. A healthy male adult must have BUN levels from 8 to 24 mg/dL, while a healthy female adult should have it from 6 to 21mg/dL. The normal BUN levels for children fall between 5 and 18 mg/dL. Meanwhile, the healthy BUN level for pregnant women is from 5 to 12 mg/dL. The normal BUN levels for children and women are relatively low due to their bodiesâ ability to split up protein molecules. Oftentimes, the BUN test is done together with the Creatinine test to figure out renal problems.