Abstract: A method and associated apparatus for measuring chemical concentration in a liquid sample based on spatial separation and resolution of light is disclosed. The method is preferably applied to sensitive, quantitative, luminescence-based biosensors which reads the analyte concentration via spatial distribution of the emitted light. The detection of light is used to assess the spatial position, rather than the intensity or wavelength, of emitted light. A bioluminescent or chemiluminescent reaction requiring, for example, ATP, NADPH or NADH as a specific, and sensitive co-factor is used. ATP or NADH concentration is modulated, “tuned,” and/or regulated via, for example, an enzyme which consumes (“consumase”) ATP, NADPH, or NADH, thereby producing a spatial distribution of ATP or NADH and a spatial distribution in the emitted light.

Abstract: Decorative surface coverings comprising a multicolored, fused plastisol layer comprising (a) a fused plastisol composition of a first color; and (b) a fused plastisol composition of a second color, the second colored plastisol being distributed within the first colored plastisol such that the multicolored plastisol layer exhibits color gradients between the first and second colored plastisols. According to certain aspects the invention, the decorative surface covering products comprise a patterned solid plastisol mixture having a three dimensional appearance. Methods for manufacturing such decorative surface coverings comprise the steps of (a) applying to a substrate a coating of a first colored fluid plastisol; (b) distributing in the first colored fluid plastisol a second colored fluid plastisol to form a patterned fluid plastisol mixture; and (c) forming the patterned fluid plastisol mixture into a patterned solid plastisol mixture.