With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Purple is a collection of songs.
text_B: Intensity-fading MALDI is a term coined to rename an existing method originally reported in 1999 to indirectly study a Protein -- protein interaction or other protein complex and the same year applied to a biological mixture to study the antigenicity of the influenza virus .. It involves treating a protein and a potential binding partner with a site-specific endoproteinase with the binding sites identified by their reduced area -LRB- or intensity -RRB- in a MALDI mass spectrum compared to that of non-bound protein control .. The basis of the approach and a range of applications including those employing gel based separations , drug-protein interactions and the relative affinity of such interactions , are described in a recent review article .
not_related.