Abstract: The microbial decontamination of soils contaminated with hydrocarbons, in particular with mineral oils, by microbial oxidation is improved by a process in which in addition to supplying the oxygen necessary for degradation, by aeration, soluble nutrients, water and soluble or dispersed biosurfactants as such or mixed with chemical surfactants are metered into the contaminated soils directly or into the removed contaminated soil layers, in one or more batches at time intervals, in an amount such that the formation of toxic intermediates which slow down or block microbial degradation in prevented, the accessibility of mineral oils and their products for the microorganisms is simultaneously increased and, as a result, accelerated, virtually complete mineralization by respiration to CO.sub.2 and H.sub.2 O is effected.

Abstract: Acidic, aqueous hair treatment emulsions, in which an active ingredient combination of phospholipids of natural origin and inorganic and/or organic acids is used, improve the wet and dry combability and reduce the electrostatic charging of hair.

Abstract: An arrangement of optical resonators which are composed of elongated optical waveguides comprising reflectors arranged at their end faces, one group of the waveguides being coupling resonators and a second group of the waveguides being useful resonators which are arranged in a substrate with the useful resonators being adjacent one surface thereof. A laser active material is provided adjacent the one surface of the substrate and can be either a semiconductor laser material or can be a light pump laser material. At least one of the waveguides of the useful resonators being composed of optically passive material, which has good wave-conducting properties, and being positioned adjacent to the laser active material so that a wave field excited in the waveguide can be intensified by the laser active material.

Abstract: A valve stem retainer provides improved frictional engagement between the retainer segments and the valve stem. The retainer includes a pair of retainer lock segments, each of the segments having a radius of curvature less than the radius of curvature of the valve stem on which the segments are installed. The segments are expanded by deformation elastically into conformity with the valve stem and when so installed, provide tight frictional engagement with the valve stem. The segments define, in a first position on the valve stem, a pair of diametrically opposed gaps along a portion of the periphery of the valve stem. For the improved results of the present invention, it was found that the ratio of the width of the pair of gaps to the radius of the valve stem should be carefully controlled.