eyeball. 1  Photoreceptors are the cells in the retina that respond to light. Their distinguishing feature is the presence of large amounts of tightly packed membrane that contains the photopigment rhodopsin or a related molecule.
In chemical analysis,  matrix refers to the components of a sample other than the analyte of interest. The matrix can have a considerable effect on the way the analysis is conducted and the quality of the results obtained; such effects are called matrix effects. For example, the ionic strength of the solution can have an effect on the activity coefficients of the analytes.
maÂ·triÂ·ces (mÄâ²trÄ­-sÄzâ², mÄtâ²rÄ­-) or maÂ·trixÂ·es. 1. A situation or surrounding substance within which something else originates, develops, or is contained: Freedom of expression is the matrix, the indispensable condition, of nearly every form of freedom (Benjamin N. Cardozo).2.The womb.quare matrix-a matrix with the same number of rows and columns. real matrix-a matrix whose elements are all real numbers. transpose-a matrix formed by interchanging the rows and columns of a given matrix.