Iron and Zinc

Copper, nickel, cobalt, iron, and zinc (270) for their physical properties using ultraviolet and infrared spectrometry (271). 

In steel-on-steel lubrication with a zinc dialkyl dithiophosphate additive, a complex surface paste appears to form first of zinc particles and iron dithiophosphate. The iron dithiophosphate then thermally degrades to a brown surface film of ZnS, ZnO, FeO, plus some iron and zinc... 

The addition of stabilizers to tetrachloroethylene inhibits corrosion of aluminum, iron, and zinc which otherwise occurs in the presence of water (12). Where water in excess of the solubiUty limit is present, forming separate layers, hydrolysis and corrosion rates increase. System design and constmction materials should consider these effects. 

Raki, a Turkish alcoholic drink was also analyzed by differential pulse polarography and copper, iron and zinc could be determined. For the arsenic content in beer a more sensitive method had to be applied. For this method a new catalytic method is established and the arsenic content was determined by using this new method. 

The side chains of the 20 different amino acids listed in Panel 1.1 (pp. 6-7) have very different chemical properties and are utilized for a wide variety of biological functions. However, their chemical versatility is not unlimited, and for some functions metal atoms are more suitable and more efficient. Electron-transfer reactions are an important example. Fortunately the side chains of histidine, cysteine, aspartic acid, and glutamic acid are excellent metal ligands, and a fairly large number of proteins have recruited metal atoms as intrinsic parts of their structures among the frequently used metals are iron, zinc, magnesium, and calcium. Several metallo proteins are discussed in detail in later chapters and it suffices here to mention briefly a few examples of iron and zinc proteins. 

At the normal galvanising bath temperature of 445-465°C, the reaction between iron and zinc is usually parabolic with time, so that the rate of reaction is rapid at first but then slows down. 

The conditions which affect the type of reaction are bath temperature and the composition of iron or steel which is being coated. At 480-520°C the reaction between iron and zinc can be linear with time so that the thickness of the alloy layers will increase in direct proportion to the immersion time and the reaction will continue to be relatively rapid. With some steels (e.g. some silicon-killed steels), the reaction can be linear at the normal galvanising temperature of about 450 C. 

ASTM B695, Coatings of Zinc Mechanically Deposited on Iron and Zinc, ASTM (1985) James, D. G., Mechanical Deposition —Hydrogen Embrittlement Study . Paper to IMF Annual Conf., UK (1985)... 

In the presence of suffident metal ions such as zinc, phosphate defidency is known to inhibit growth and increase yields of dtric add. However, phosphate is added not only as a source of phosphorus but also as phosphoric add to addify the medium. Restricted growth but good citric add yield is also achieved by maintaining iron and zinc defidency hence low phosphate levels are not necessary. 

MORAis M B, FESTE A, MILLER R G, LiFSCHiTZ c H (1996) Effect of resistant and digestible starch on intestinal absorption of calcium, iron, and zinc in infant pigs. Pediatr Res. 39 872-6. 

The lipid in muscle is composed primarily of triglycerides (depot fats) and of phospholipids (membrane components), and is a constituent which varies enormously not only in amount present, but also in properties such as degree of saturation (species dependent). The ash of lean meat is comprised of various minerals such as phosphorus, potassium, sodium, magnesium, calcium, iron and zinc Carbohydrate was not noted in the proximate composition because while some may be present, it is normally there in low concentration compared to the other constituents. Glycogen is the carbohydrate occurring in greatest concentration in muscle but is normally degraded soon after the animal is sacrificed. 

Additional hypotheses for their mechanism of action have more recently been proposed. It is well known that proanthocyanidins are able to complex metals through their ortho-diphenol groups. This property is often viewed as imparting negative traits (e.g., reduction of the bioavailability of essential mineral micronutrients, especially iron and zinc) [87]. Since iron depletion causes severe limitation to microbial growth, their ability to bind iron has been suggested as one of the possible mechanisms explaining the antimicrobial activity of proanthocyanidins [88] (Table 1). 

Temperature and sulfur fugacity estimated from iron and zinc partitioning between coexisting stannite and sphalerite and coexisting stannoidite and sphalerite... 

Stannite is the most common tin sulfide mineral in the ore deposits associated with tin mineralization. This mineral sometimes contains appreciable amounts of zinc, together with iron. Several workers have suggested that the zinc and iron contents of stannite are related to temperature. With respect to the study of the phase relationships in the pseudobinary stannite-kesterite system. Springer (1972) proposed zincic stannite as a possible geothermometer mainly based on the chemical compositions of the two exsolved phases (stannite and kesterite). Nekrasov et al. (1979) and Nakamura and Shima (1982) experimentally determined the temperature dependency of iron and zinc partitioning between stannite and sphalerite. 

Iron and zinc partitioning between stannite and sphalerite is represented by the exchange reaction. 

Nekrasov et al. (1979) and Nakamura and Shima (1982) reported a temperature dependency of iron and zinc partitioning between stannite and sphalerite (Fig. 1.177)... 

Camire (2002) showed that texturization does not seem to have a great effect on mineral retention and bioavailability. Others have reported increased retention of ascorbic acid in rice- and maize-based snacks (Hazell and Johnson, 1989 Plunkett and Ainsworth, 2007), increased iron diffusibility and absorption of iron-complexed protein (Poltronieri et al, 2000 Watzke, 1998), and no difference in iron and zinc absorption in human subjects fed textured bran-flour (Fairweather-Tait et al, 1989). 

Eairweather-Tait, S. J., Porhvood, D. E., Symss, L. L., Eagles, J., and Minski, M. J. (1989). Iron and zinc absorption in human subjects from a mixed meal of extruded and nonextruded wheat bran and flour. Am. ]. Clin. Nutr. 49, 151-155. 

Another good example of the chlorination of sulfide ores involves the following reactions. The complex sulfide ore contains pyrite, cassiterite, and zinc blende. Chlorination of the ore with elemental chlorine results in the formation of iron and zinc chlorides ... 

A solution containing the chlorides of copper, nickel, iron, and zinc is considered. In this case, two anodic reaction are possible... 

There are problems as well in the absorption of certain drugs in the presence of specific food components. L-Dopa absorption may be inhibited in the presence of certain amino acids formed from the digestion of proteins [43], The absorption of tetracycline is reduced by calcium salts present in dairy foods and by several other cations, including magnesium and aluminum [115-117], which are often present in antacid preparations. In addition, iron and zinc have been shown to reduce tetracycline absorption [118], Figure 17 illustrates several of these interactions. These cations react with tetracycline to form a water-in-soluble and nonabsorbable complex. Obviously, these offending materials should not be co-administered with tetracycline antibiotics. 

Lilis R, Eisinger J, Blumberg W, et al. 1978. Hemoglobin, serum iron, and zinc protoporphyrin in lead-exposed workers. Environ Health Perspect 25 97-102. 

Knudtsen K., O Connor G.A. Characterization of iron and zinc in Albuquerque sewage sludge. J Environ Qual 1987 16 85-90. 

Shuman L.M. Effects of tillage on the distribution of manganese, copper, iron, and zinc in soil fractions. Soil Sci Soc Am J 1985b 49 1117-1122. 

While it seems that there is little interference between iron and zinc metabolism under normal dietary situations, the possibility of interference must be taken into account when considering iron or zinc supplementation in developing countries. 

Ali HI and Harland BF (1991) Effects of fiber and phytate in sorghum flour on iron and zinc in weanling rats - a pilot-study . Cereal Chemistry, 68, 234-238. 

House W A (1999), Trace element bioavailability as exemplified by iron and zinc , Field Crops Res, 60, 115-141. 

Clarification of copper interactions with molybdenum, sulfate, iron, and zinc in plant and animal metabolisms (NAS 1977 Eisler 1989, 1993)... 

Falandysz, J., W. Kotecka, and K. Kannan. 1994. Mercury, lead, cadmium, manganese, copper, iron and zinc concentrations in poultry, rabbit and sheep from the northern part of Poland. Sci. Total Environ. 141 51-57. Fernandez, T.V. and N.V. Jones. 1990. Studies on the toxicity of zinc and copper applied singly and jointly to Nereis diversicolor at different salinities and temperatures. Trop. Ecol. 31 47-55. 

Sumi, Y., H.R. Fukuoka, T. Murakami, T. Suzuki, S. Hatakeyama, and K.T. Suzuki. 1991. Histochemical localization of copper, iron and zinc in the larvae of the mayfly Baetis thermicus inhabiting a river polluted with heavy metals. Zool. Sci. (Japan) 8 287-293. 

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