Secondary pigment

O2 oxidoreductase (E.C. 1.10.3.1.) and peroxidase (E.C. 1.11.1.7.) contribute to secondary pigment formation during curing processes (J ) and during stresses to plants caused by ozone ( > ) diseases, chemicals, physical wounding and adverse temperatures, moisture and nutrient levels (, ). The resulting pigments contribute to abnormal foliar and food coloration (6) and flavors (, 7) of plants and plant products. 

The RI of any material (primary or secondary pigment) is a key to its performance. As is well known, the larger the difference in RI between the pigment and the medium in which it is dispersed, the greater the opacity effect. A summary of the refractive indices of various extender and opacifying pigments is provided in Table 18.1. 

An excellent example of employing secondary pigment to enhance the absorption properties of the porphyrin was reported by Lindsey, Holten, Bocian, Birge and coworkers. They designed and. synthesized light-harvesting arrays... 

Of the mineral forms, only hematite appears to have been mined and used in its massive form these compounds otherwise occur as greater or lesser components in secondary pigments such as the ochres, umbers and siennas qq.v.), either in the natural state or from calcination. Akaganeite, lepidocrocite and maghemite (with pyrolusite) have been identified by Zolensky (1982) in prehistoric pictographs in Seminole Canyon, USA. 

Use of dimethylaminoethyl (also rert-butylaminoethyl) methacrylate as a monomer permits the introduction of pendent amino groups which can serve as sites for secondary cross-linking, provide a way to make the copolymer acid-soluble, and provide anchoring sites for dyes and pigments. 

Ziac sulfate was made by 15 companies ia 1980 from secondary materials (93%) and from roasted ore, ie, ziac oxide (7%). The ziaciferous material reacts with sulfuric acid to form a solution, which is purified. After filtration, the solution is heated to evaporation and heptahydrate crystals are separated. It is sometimes sold ia this form but usually as the monohydrate [7446-19-7] which is made by dehydration at ca 100°C. Very pure ziac sulfate solution is made ia the manufacture of the pigment Hthopone [1345-05-7] ZnS-BaSO, and of ziac by electrowinning (see ZiNC AND ZINC ALLOYS). 

Cadmium hydroxide is the anode material of Ag—Cd and Ni—Cd rechargeable storage batteries (see Batteries, secondary cells). Cadmium sulfide, selenide, and especially teUuride find utiUty in solar cells (see Solarenergy). Cadmium sulfide, Hthopone, and sulfoselenide are used as colorants (orange, yellow, red) for plastics, glass, glazes, mbber, and fireworks (see Colorants for ceramics Colorants forplastics Pigments). 

C-coupling is of outstanding importance in the azo coupling reaction for the synthesis of azo dyes and pigments. An aromatic or heteroaromatic diazonium ion reacts with the so-called coupling component, which can be an aromatic primary, secondary, or tertiary amine, a phenol, an enol of an open-chain, aromatic, or heteroaromatic carbonyl compound, or an activated methylene compound. These reactions at an sp2-hybridized carbon atom will be discussed in Chapter 12. In the... 

Phenazines — This large class of compounds includes more than 6,000 natural and synthetic representatives. Natural phenazines are secondary metabolites of certain soil and marine microorganisms. The main phenazine producers are Pseudomonas and Streptomyces species. Pseudomonas strains produce the most simple phenazines tubermycin B (phenazine-1-carboxylic acid), chlororaphine, pyocyanin, and iodinine. Pyocyanin is a blue pigment while chlororaphine is green both are produced by Pseudomonas aeruginosa. They can be seen in infected wounds of animal and human skins. Iodinine is a purple phenazine produced by Pseudomonas aureofaciens. 

An anthocyanin occurs in solution as a mixture of different secondary structures, a quinonoidal base, a carbinol pseudobase, and a chalcone pseudobase. ° hi addition, different mechanisms for the stabilization of anthocyanins lead to the formation of tertiary structures such as self-association, inter-, and intra-molecular co-pigmentation. ... 

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