One remedy for a deficiency of vitamin B12 for the elderly is a regular injection of this important nutrient. The vitamin B12 injection dose depends on factors such as gender and age.
Hydrogen bonds happen in alcohols. As a matter of fact, any molecule that contains a hydrogen atom attached to an atom of nitrogen or oxygen is capable of such a bond. Ethanol is one such alcohol that features hydrogen bonds. Ammonia is an example of hydrogen bonding. In the case of ammonia, however, the hydrogen bond happens to be relatively weak.
A hydrogen bond is the attractive interaction of a hydrogen atom with an electronegative atom, like nitrogen, oxygen or fluorine (thus the name hydrogen bond, which must not be confused with a covalent bond to hydrogen). The hydrogen must be covalently bonded to another electronegative atom to create the bond.