Lastly, parietal cells synthesizedand secrete intrinsic factor which aids in the absorption of vitamin B12 by the ileum. Chief cells (B or arrow)are located, in cluster, at the base of the glands. They synthesize and secret hydrolytic enzymes, which areactivated at acid pH. These enzymes include gastric lipase, rennin and pepsin, which is secreted aspepsinogen and activated in the lumen. Pepsin hydrolyzes proteins. Rennin breaks down milk proteins andlipase initiates the digestion of fats.
A basis set in theoretical and computational chemistry is a set of functions (called basis functions) which are combined in linear combinations (generally as part of a quantum chemical calculation) to create molecular orbitals.
In mathematics, the standard basis (also called natural basis or canonical basis) for a Euclidean space is the set of unit vectors pointing in the direction of the axes of a Cartesian coordinate system. For example, the standard basis for the Euclidean plane is formed by vectors. and the standard basis for three-dimensional space is formed by vectors. Here the vector e x points in the x direction, the vector e y points in the y direction, and the vector e z points in the z direction.