Abstract: Embodiments of the disclosure provide a structure with a guard ring between the terminals of a single photon avalanche diode photodetector (SPAD), and related methods. A structure according to the disclosure includes a SPAD with an anode within a doped well and a cathode within the doped well. A guard ring includes a semiconductor material within the doped well. The semiconductor material and the doped well have opposite doping polarities.

Abstract: The present invention provides a process for the preparation of a compound of the formula wherein Y represents —O—, —S— or —N(R2)—, R2 being hydrogen, C1-C10alkyl or aralkyl; Z represents a 2,5-furanyl, 2,5-thiophenyl, 4,4?-stilbenyl or a 1,2-ethylenyl residue and R1 represents hydrogen, halogen, C1-C10alkyl, C1-C10alkoxyl, cyano, COOM or SO3M, M being hydrogen or an alkaline or alkaline earth metal, characterized by reacting a compound of the formula with a dicarboxylic acid of the formula HOOC-Z-COOH ??(3) or an ester thereof, Y, Z and R1 being as previously defined, in N-methylpyrrolidone or N,N-dimethylacetamide, in the presence of an acidic catalyst and, optionally, in the presence of a secondary solvent capable of removing water from the reaction mixture, which are useful as optical whitening agents for natural and synthetic materials.

Abstract: The present invention relates to novel cationic yellow dyes of formula (1) wherein R1 and R2 are each independently of the other a C1-C8alkyl radical or an unsubstituted or substituted benzyl radical, R3 is hydrogen, C1-C8alkyl, C1-C8alkoxy, cyanide or halide, preferably hydrogen and X is an anion, with the proviso that at least one of the substitutents R1 is a benzyl radical and R2 is a methyl radical, R2 is not hydrogen, also to compositions therof, especially comprising other dyes, to processes for the preparation therof and to the use therof in the dyeing of organic material, such as keratin, wool, leather, silk, cellulose or polyamides, especially keratin-containging fibres, cotton or nylon, and preferably human hair.

Abstract: A process for the preparation of certain cationic azo compounds is described, as well as the use thereof for dyeing keratin-containing fibres, especially human hair, in which specific cationic azo dyes are used.

Abstract: The present invention relates to novel cationic yellow dyes of formula (1) wherein R1 and R2 are each independently of the other a C1-C8alkyl radical or an unsubstituted or substituted benzyl radical, R3 is hydrogen, C1-C8alkyl, C1-C8alkoxy, cyanide or halide, preferably hydrogen and X is an anion, with the proviso that at least one of the substitutents R1 is a benzyl radical and R2 is a methyl radical, R2 is not hydrogen, also to compositions therof, especially comprising other dyes, to processes for the preparation therof and to the use therof in the dyeing of organic material, such as keratin, wool, leather, silk, cellulose or polyamides, especially keratin-containging fibres, cotton or nylon, and preferably human hair.

Abstract: The present invention provides a process for the preparation of a compound of formula (I) wherein Y represents —O—, —S— or —N(R2)—, R2 being hydrogen, C1-C10alkyl or aralkyl; Z represents a 2,5-furanyl, 2,5-thiophenyl, 4,4′-stilbenyl or a 1,2-ethyleny residue and R1 represents hydrogen, halogen, C1-C10alkoxyl, cyano, COOM or SO3M, M being hydrogen or an alkaline or alkaline earth metal, characterized by reacting a compound of formula (II) with a dicarboxylic acid of formula (III): HOOC-Z-COOH, or an ester thererof, Y, Z and R1 being as previously defined, in N-methylpyrrolidone or N,N-dimethylacetamide, in the presence of an acidic catalyst and, optionally, in the presence of a secondary solvent capable of removing water from the reaction mixture, which are useful as optical whitening agents for natural and synthetic materials.