Decoration (noun). specifically, any mark of honor to be worn upon the person, as a medal, cross, or ribbon of an order of knighthood, bestowed for services in war, great achievements in literature, art, etc. Origin: [LL. decoratio: cf.
A P-N junction (or N-P junction) is formed by creating two substrate materials of P type and N type on a semiconductor. P type means it is doped with free holes (electron depletion) and the N type is doped with electrons. Of course by physics, the free holes and free electrons would like to neutralize each other.
Type IV Hypersensitivity is referred to as delayed hypersensitivity and involves Th1 T-Cells attracting and activating Macrophages. It is called delayed because it takes a few days to kick in. This type of hypersensitivity is Cell-Mediated and Antibody Independent. Type IV Hypersensitivity is the only type of hypersensitivity that doesnât involve antibodies. Examples include Contact Dermatitis (poison ivy and cheap nickel jewelry), PPD (TB skin test) & Multiple Sclerosis (T-Cells attack myelin).