The invention discloses a method, a system, a computer program and a device for determining the surface charge andor dipole densities on heart walls. Pharmaceutical compositions containing such peptides and kits for use in diagnosis of IDDM are also disclosed. The present invention further relates to a method of screening compounds and sample solutions for a GPCR agonist, antagonist, inverse agonist, or desensitization active compound. The liquid crystal domains in the liquid crystal composition rotate away from a planar state in the presence of an applied electric field and the degree of rotation is a function of the applied electric field strength.