Abstract: Thixotropic compositions comprising a solution of a urea urethane having the formula as hereinafter set out dissolved in a polar aprotic solvent containing 0.1-2.0 mol LiCl per urea group:R--O--CO--NH--R'--NH--CO--NH--R"--NH--CO--NH--R'--NH--CO--ORwherein R represents C.sub.n H.sub.2n+1 -- or C.sub.m H.sub.2m+1 (C.sub.p H.sub.2p O).sub.r --; n represents an integer having a value of from 4 to 22; m represents an integer having a value of from 1 to 18; p represents an integer having a value of from 2 to 4; and r represents an integer having a value of from 1 to 10. ##STR1## The solids content in the aprotic solvent amounts to 10-75 wt. % and preferably to from 40-60 wt. %.

Abstract: Stabilized, insolubilized biochemical materials are prepared by covalently bonding a biochemical material such as an antigen, antibody, hormone, or enzyme to a silicic acid heteropolycondensate layer which is applied to a mechanically stable support. The insolubilized biochemical materials are useful as separating agents or adsorbents in radio-immuno assays or affinity chromatography.

Abstract: Radioactively tagged erythrocytes suitable for scintigraphic display.