Another matrix frequently used in geometrical situations is the Jacobi matrix of a differentiable map f: Rn → Rm.
For example, Blosum50 and Pam250 scoring matrices are frequently used to detect proteins sharing less than 50% of amino acid identities [ 53].
Blood and urine are the most frequently used matrices for exposure assessment using biomonitoring.
Frequently used matrices for preparing calibrators are human serum and human or bovine serum albumin-based solutions.
A matrix-type structure is frequently used to assemble the right teams for the appropriate problems.
Urine is probably the most frequently used matrix in humans to quantify the degree of environmental or occupational exposure to pollutants, especially for substances with short biological half-lives [ 3, 18].
Matrix-matched calibration curves are frequently used to compensate for any matrix effects and to avoid inaccurate quantitation.
Besides the ordinary matrix multiplication just described, there exist other less frequently used operations on matrices that can be considered forms of multiplication, such as the Hadamard product and the Kronecker product.
Metal matrix composite (MMC) coatings composed of nickel-based matrices and tungsten carbides (WC/W2C) are frequently used to solve problems of reduced life time under severe abrasive and corrosive conditions.
However, the QAT was included in our matrix since it is very frequently used in public health.
