absorption spectroscopy article 20 priority journal 18 controlled study 14 nonhuman 12 unclassified drug 12 Article 8 photochemistry 8 Animals 6 Indoles 6 Molecular Structure 6 Oxidation-Reduction 6 Raman spectrometry 6 aqueous solution 6 dye 6 fluorescence 6 fluorescence spectroscopy 6 pH 6 Amines 4 Chlorophyll 4 Fluorescence 4 Heme 4 Hydrogen-Ion Concentration 4 Kinetics 4 Mice 4 Oxygen 4 Photochemistry 4 Radiation-Sensitizing Agents 4 Singlet Oxygen 4 absorption 4