Methods for detecting receptivity of mammalian endometrium to embryo implantation comprising obtaining a sample of the endometrium, contacting the endometrium with a monoclonal antibody for 3 and detecting 3 in the endometrium. The apparatus includes an ink reservoir for containing a water based ink and a moisture barrier positioned between the ink in the ink reservoir and ambient air. The display screen is mounted on a support fitted with a pivot to a moveable collar slidably mounted on vertical column. The adjustment assembly adjusts the height of the industrial caster wheel by adjusting the pressure applied by the adjustable axle to the support member. The area of the p-n junction in the second loading unit is not equal to the area of the p-n junction in the first loading unit.