Neurotransmitters and hormones are the chemicals which control every system and process within the body. Norepinephrine is both a neurotransmitter and a hormone. As a result, its role within the body is essential to normal body and brain function.orepinephrine's role as a brain and body stimulant requires a certain level of this chemical to be present to achieve normal mental and emotional function. Its primary mechanism is that of arousal.
A normal diamond pickaxe has 1562 durability so it may get you as much stone with that pickaxe. With Unbreaking III however, that may quadruple your mining count, or around 6248 stone. Efficiency enchantment just makes mining faster and does not improve durability. Sources: http://minecraft.gamepedia.com/Pickaxe
Probably also cheaper in terms of XP to just repair it, not to mention materials - one diamond restores 25% durability, so with Unbreaking III you effectively make a new pickaxe with 1/3 of the diamonds (you may also be able to repair it by combining it with a new pickaxe, which would give you 4x the uses per diamond if you repair it when the durability is nearly gone, probably safer to just use 1-2 diamonds so you can keep durability above 25-50%).