"The J-1500 is a hybrid instrument consisting of a variable wavelength polarimeter for CD or LD and absorption spectrophotometer (~180-900 nm, Far-UV to Vis range). Circular dichroism (CD) measures the difference in absorbance of left- and right- handed polarized light of chiral molecules. CD is commonly used to analyse the conformation of macromolecules, particularly protein secondary structure.Linear dichroism (LD) measures the difference in absorption of light linearly polarised parallel and perpendicular to the orientation axis. LD can be used to give information about the conformation and orientation of structures with molecules that are either intrinsically oriented, or can be oriented during an experiment by external forces such as DNA complexes, fibrous proteins and membrane peptides/proteins in liposomes."