Abstract: A multilayer dry immunoassay element comprising 1) a spreading layer having a sample application area and a signal read area and 2) a separate receptor layer residing on 3) a radiation-transmissive support characterized in that the spreading layer contains a light absorbing material.

Abstract: Nucleic acids can be amplified and detected using an element which has a sealable support on which is disposed a nucleic acid reagent composition. The composition is a mixture of a nucleic acid reagent composed of polymeric particles to which an oligonucleotide is covalently attached. The particles are prepared from a first polymer having a glass transition temperature of at least about 70.degree. C. and have an average diameter of from about 0.1 to about 3 micrometers. The reagent is adhered to the support using a water insoluble adhesive comprising a second polymer which has a glass transition temperature which is at least about 30.degree. C. less than the glass transition temperature of the first polymer. The adhesive is present in the composition at from about 1 to about 20 dry weight percent. The method provides high sensitivity and low background in the assay of nucleic acids, preferably using polymerase chain reaction.

Abstract: A dry immunoassay analytical element, for assaying a ligand is disclosed. The element comprises, in the following order, (a) a layer containing a labeled ligand, (b) a bead spreading layer, c) a cross-linked hydrophilic polymer layer and d) a support; wherein(i) a fixed concentration of an immobilized receptor for the labeled ligand is located in a zone at the interface of layers (b) and (c); and(ii) the receptors are immobilized by being covalently bonded to polymeric beads that are smaller than the beads in layer (c).

Abstract: Photographic elements are described which comprise a support having thereon at least one image dye-providing layer unit and at least one layer containing an immobile anionic organic acid having an equivalent weight based on acid groups of at least 70 and less than 800. In one embodiment, photographic elements of this invention can be contacted with a transition metal-ion complex such as a cobalt(III) ion complex before contact with a fixing bath and sufficient transition metal ion will be retained in the photographic element to bleach the silver in said element.

Abstract: Photographic elements are described which comprise a support having thereon at least one image dye-providing layer unit and at least one layer containing an immobile anionic organic acid having an equivalent weight based on acid groups of at least 70 and less than 800. In one embodiment of this invention, photographic elements can be contacted with a transition metal-ion complex such as a cobalt(III) ion complex before contact with a fixing bath and sufficient transition metal ion will be retained in the photographic element to bleach the silver in said element.