Abstract: The invention relates to an actuation and evaluation circuit for a laser diode (1) and a photodiode (3) for determining the concentration of a gas. The laser diode can generate light in the range of an absorption line of the gas. The circuit comprises a driver (10, 11, 12, 13) for generating a driving signal (17) for the laser diode (1), an assembly (8, 9) for generating a reference signal (20), and a subtractor (5) for subtracting the reference signal (20) from the signal (21) supplied by the photodiode. The invention further relates to a measuring device for determining the concentration of a gas by means of such an actuation and evaluation circuit. Finally, the invention relates to a corresponding method.

Abstract: The invention relates to an actuation and evaluation circuit for a laser diode (1) and a photodiode (3) for determining the concentration of a gas. The laser diode can generate light in the range of an absorption line of the gas. The circuit comprises a driver (10, 11, 12, 13) for generating a driving signal (17) for the laser diode (1), an assembly (8, 9) for generating a reference signal (20), and a subtractor (5) for subtracting the reference signal (20) from the signal (21) supplied by the photodiode. The invention further relates to a measuring device for determining the concentration of a gas by means of such an actuation and evaluation circuit. Finally, the invention relates to a corresponding method.

Abstract: Oxidation colorants which contain at least one secondary intermediate and at least one derivative of 5,6-dihydroxyindoline corresponding to formula (I): ##STR1## in which--independently of one another--R.sup.1 is hydrogen, a C.sub.1-4 alkyl group or a C.sub.1-4 hydroxyalkyl group,R.sup.2 is hydrogen or a --COOH group which may even be present as a salt with a physiologically compatible cation,R.sup.3 is hydrogen or a C.sub.1-4 alkyl group,R.sup.4 is hydrogen, a C.sub.1-4 alkyl group or a group --CO--R.sup.6 where R.sup.6 is a C.sub.1-4 alkyl group andR.sup.5 is one of the groups mentioned for R.sup.4,or a physiologically compatible salt of these compounds with an organic or inorganic acid in an aqueous carrier and which are free from oxidation dye precursors of the primary intermediate type enable hair to be colored in particular in black tones with no tinges of red. In particular, completely or partly grey hair can be colored in tones which come very close to the color of the hair before greying.

Abstract: Liquid preparations for oxidation hair dyes, which contain soaps, water-soluble cationic polymers and hair dye intermediates in an aqueous or aqueous-alcoholic carrier, can be stabilized by amines corresponding to formula (C) ##STR1## in which R.sup.1 is a C.sub.8-22 alkyl group,R.sup.2 is hydrogen or a C.sub.8-22 alkyl group,R.sup.3 is hydrogen except when r=q=0 and then is C.sub.1-4 alkyl, andm, n, o, p, q and r are numbers of 0 to 6.

Abstract: This invention relates to a hair dye preparation. More specifically, this invention relates to a preparation for the simultaneous coloring, washing, and conditioning of human hair which consisting essentially of a mixture of:(a) a coupler-developer oxidation coloring agent;(b) a cationic polymer;(c) an anionic surfactant;(d) an amphoteric surfactant; and(e) conventional cosmetic aids selected from the group consisting of direct dyestuffs, wetting agents, thickeners, perfumes, and water.

Abstract: This invention is directed to an aerosol container system with two separate chambers, each of which contains a component to be mixed with the other component just prior to use.

Abstract: Emulsion-form hydrogen peroxide compositions in the form of an oil-in-water emulsion containing oil or fatty components, emulsifiers and hydrogen peroxide and, in addition, a thickening agent comprising a carboxyl-group containing polymer or copolymer soluble in aqueous alkali in a quantity of from about 1 to about 5% by weight solids, based on the weight of the composition. These compositions are particularly suitable as an oxidizing component in processes for the dyeing or lightening of hair resulting in improved depth of color and brightness.

Abstract: This invention is directed to oxidation hair dye compositions and their use in the dyeing of human hair. The compositions consist essentially of precursors comprising 2,3-diamino-6-methoxy-pyridines and aromatic amines or diamines. The combination of oxidation dye precursors according to the invention gives bright, deep blue dye finishes having high stability to heat and light.

Abstract: Stabilized liquid preparations for oxidation hair dyes are provided. The oxidation hair dyes comprise oxidation hair dye precursors and an aqueous or aqueous-alcoholic carrier, containing (A) from 5 to 20% by weight of fatty acid water-soluble soap and (B) from 0.5 to 10% by weight of a water-soluble cationic polymer. The oxidation hair dyes (containing a soap and cationic polymer which tend towards inhomogeneity) are stabilized by the addition of from 5 to 30% by weight of a compound selected from the group consisting of: (C) aliphatic or alicyclic C.sub.9 -C.sub.44 dicarboxylic acid water-soluble salts; and (D) amines corresponding to the following general formula ##STR1## .