Effect of iron concentration

Fig. 12.1. Effect of iron concentration on yield of citric acid by A. niger.

Spin-trapping experiments connected with biological superoxide production have also been used to examine the biochemistry of anti-tumour antibiotics bleomycin (Sugiura and Kikuchi, 1978) and mitomycin C (Lown et al., 1978), as well as the effect of iron concentration on xanthine oxidase reactions (Buettner et al., 1978), and the photochemistry of melanins (Felix et al., 1978). 

S.P. Sweet and L.J. Douglas, Effect of iron concentration of siderophore synthesis and pigment production by Candida albicans, FEMS Microbiol. Lett., 80, 87, 1991. 

Effect of Iron Concentration. Among the factors that influence kohs, the effect of the amount of iron surface area that is accessible to the contaminant has received the most attention. This effect is most often described by a linear relationship ... 

Effects of iron concentration on pigment composition in Phaeocystis antarctica grown at low irradiance... 

Figure 5.1 Effect of oxygen concentration on corrosion of mild steel in slowly moving water containing 165 ppm CaCl2 48-hour test, 25°C. [Courtesy of H. H. Uhlig, D. N. Triadis, and M. Stern, Effect of Oxygen, Chlorides, and Calcium Ion on Corrosion Inhibition of Iron by Polyphosphates, J. Electrochem. Soc. 102, p. 60 (1955). Reprinted with permission by The Electrochemical Society, Inc. ]...

Another subsidiary field of study was the effect of high concentrations of a diffusing solute, such as interstitial carbon in iron, in slowing diffusivity (in the case of carbon in fee austenite) because of mutual repulsion of neighbouring dissolved carbon atoms. By extension, high carbon concentrations can affect the mobility of substitutional solutes (Babu and Bhadeshia 1995). These last two phenomena, quenched-in vacancies and concentration effects, show how a parepisteme can carry smaller parepistemes on its back. 

Effects of oxygen concentration on the reaction over iron phosphate catalyst... 

A. Walter, A. Pich, G. Scholz, H. Marschner, and V. Romheld, Effects of iron nutritional status and time of day on concentrations of phytosiderophores and nico-tianamine in different root and shoot zones of barley. J. Plant Nutr. 18 1511 (1995). 

The parameter most commonly monitored in this research is the extent of hydrogen peroxide decomposition. Measurement of tensile strength and/or the degree of polymerisation can be useful indicators of fibre damage. The effect of iron(III) ion concentration in accelerating the rate of peroxide decomposition is shown in Figure 10.23,... 

In a review of the course and mechanism of the catalytic decomposition of ammonium perchlorate, the considerable effects of metal oxides in reducing the explosion temperature of the salt are described [1], Solymosi s previous work had shown reductions from 440° to about 270° by dichromium trioxide, to 260° by 10 mol% of cadmium oxide and to 200°C by 0.2% of zinc oxide. The effect of various concentrations of copper chromite , copper oxide, iron oxide and potassium permanganate on the catalysed combustion of the propellant salt was studied [2], Similar studies on the effects of compounds of 11 metals and potassium dichromate in particular, have been reported [3], Presence of calcium carbonate or calcium oxide has a stabilising effect on the salt, either alone or in admixture with polystyrene [4],... 

The effects of oxygen concentration with a catechol feed rate of 18 x 10 mmol/ min and the effect of catechol feed rate with 3% oxygen on the cracking of catechol over nanoparticle iron oxide were studied at 280°C temperature. There was an increase in the conversion of catechol with an increase in oxygen concentration and a decrease in catechol feed rate (lower concentration) as illustrated in Fig. 12.5. 

FIGURE 12.5. Effects of oxygen concentration and feed rate on catechol conversion over iron ox-... 

FIGURE 12.10. Effect of oxygen concentration on the fractional concentration of products resulting from catechol cracking over iron oxide/quartz chips with a feed rate of 18 x 10 mmol/min at (a) 280°C and (b) 330°C for primary (P) and secondary I (S-I)products that are derived by factor... 

Similar deleterious effects of small concentrations (that is, 0.001% to 0.005%) have been well documented for bismuth and antimony. Similarly, these effects were overcome by additions of small amounts of the rare earth elements. In the industry, it is accepted that roughly 0.01% cerium (once again as mischmetal that contains 50% cerium and approximately 50% lanthanum, neodymium and praseodymium) will neutralize the effects of the deleterious elements. The result is the production of high quality nodular iron, while still allowing for the use of commercially available steel scrap as a raw material. 

All enzymes exhibit various features that could conceivably be elements in the regulation of their activity in cells. All have a characteristic pH optimum which makes it possible for their catalytic rates to be altered by changes in intracellular pH (e.g. in ribulose diphosphate carboxylase(l7>). The activities also depend on the concentration of substrates, which may vary according to intracellular conditions. Moreover, many require metal ions or vitamins, and the activity of enzymes may be a function of the concentrations in which such materials are present (e.g. the effect of iron limitation on the citric acid fermentation of Aspergillus niger ). However, over and above these factors, some enzymes have other properties that... 

Most of the transition elements can form complexes with transferrin and other proteins in serum, and can be stored in ferritin. This accounts for the effect of iron metabolism when the concentrations of these metals rise. Limited information which shows the presence of specific transport and storage systems is available on some metals. 

Iron-nickel alloys are known to dissolve in the aluminium melts non-selectively. " As seen from Table 5.3, during dissolution of a 50 mass % Fe-50 mass % Ni alloy the ratio, cFe cNi, of iron to nickel concentrations in the melt is 1.00 0.05, i.e. it is equal to that in the initial solid material. The same applies to other alloys over the whole range of compositions. Respective saturation concentrations are presented in Table 5.4. The data obtained display a strong mutual influence of the elements on their solubilities in liquid aluminium because in its absence the solubility diagram for a constant temperature would be like that shown by the dotted lines in Fig. 5.5, with the eutonic point, E, at 2.5 mass % Fe and 10.0 mass % Ni. The effect of iron on the nickel solubility is seen to be more pronounced than that of nickel on the iron solubility. 

Scherer MM, Tratnyek PG. Dechlorination of carbon tetrachloride by iron metal effect of reactant concentrations. 209th National Meeting, Anaheim, CA, American Chemical Society 1995 35(l) 805-806. 

Stefels J, van Leeuwe MA (1998) Effects of iron and light stress on the biochemical composition of Antarctic Phaeocystis sp. (Prymnesiophyceae). I. Intracellular DMSP concentrations. J Phycol 34 486-495 Trtilek M, Kramer DM, Koblizek M, Nedbal L (1997) Dual-modulation LED kinetic fluorometer. J Lum 72-74 597-599... 

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