Abstract: Ultraviolet (UV) radiation in the UV-C and UV-B bands, which is particularly dangerous, is absorbed and filtered by quartz glass doped with between 0.065% and 3.25%, and preferably between 0.065% and 1.3% by weight, of cerium metal, or cerium as such. Preferably, the cerium is added to quartz sand and/or rock crystal, in form of a fine-grained powder of up to 2 0 .mu.m grain size, in form of cerium aluminate (CeAlO.sub.3), present in up to about 5% by weight, and preferably up to about 2%, and melted together in a single step. The quartz glass so obtained is particularly suitable for a metal halide discharge lamp, e.g. as an outer envelope (1), or as the discharge vessel (27) itself, or for halogen incandescent lamps, to form the quartz-glass light bulb or an envelope therefor. A small quantity of titanium oxide, up to about 0.05%, may be added as a further doping agent to the melt to further improve the UV absorption in the B and C bands.

Abstract: The binding site on an immunoglobulin for a protein is blocked by hydrophobically coupling the immunoglobulin to a blocking agent such as a label. This results in a detection reagent useful in a variety of test assays in which a protein and an immunoglobulin are advantageously used together, but separately. The reagent is useful in the simultaneous determination of IgG and one of IgA or IgM. Anti-IgA-IgG or anti-IgM-IgG is coupled to a hydrophobic label, particularly a pigment or dye, which label blocks the binding site on IgG for Protein A, and labeled Protein A is added.

Abstract: Bituminous organopolysiloxanes which are capable of being cured comprising a bituminous material and a modified organopolysiloxane capable of being cross-linked.