Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Science, 1998? / Corrigenda tipped to title page. Bibliography: leaves 313-353.

Thesis (Ph.D.)--University of Western Australia, 2004.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Issued also as thesis, Kiel, 1963. / Offa-Bücher, Bd. 19.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references. Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references. Also available on the Internet.

Corrigenda tipped to title page. Bibliography: leaves 313-353. This study investigated the iron status and dietary intakes in 6-24 month old children in Australia and Ghana and assessed the effects of dietary calcium on intestinal iron absorption. The true prevalence of non-anaemic iron deficiency (NAID) and iron deficiency anaemia (IDA) and dietary intakes in infants and toddlers from a broad socio-economic background were assessed by haematological and biochemical parameters, semi-quantitative diet recall and anthropometric measurements. The high prevalence of iron deficiency and anaemia found in Australian and Ghanaian children can be attributed to the low intake of bioavailable iron in weaning diets which are often ingested with large amounts of calcium. While calcium has been shown to inhibit the absorption of iron, its mechanism of interaction with iron absorption at the intestinal level is not known. The rat was used as an experimental model to investigate the effects of dietary calcium on duodenal iron uptake. The results indicate there is a critical period during weaning when the consumption of high dietary calcium with low iron can retard growth potential. Dietary calcium significantly inhibits non-haem iron absorption at the intracellular level by up-regulating villus enterocyte ferritin concentrations under iron deficiency conditions.

Male weanling Wistar rats were fed a low-iron basal diet for 3 weeks. The iron depleted rats were then divided into 9 groups according to a randomized block design based on body weight. During the repletion period of 2 weeks, one group was fed the low-iron basal diet. The other eight groups received either the basal diet to which was added 5, 10, 15, 20 or 25 mg iron per kg diet as ferrous sulfate or test source diets formulated to provide a total of 15 mg iron per kg diet from either freeze-dried ground beef, textured defatted soy flour product or a 2.3:1 (w/w) mixture of beef and soy product. All diets were isocaloric and isonitrogenous. The relative biological value (RBV) of iron in the test source diet was calculated as the ratio of the amounts of iron from the reference source (ferrous sulfate) and the test source diet required to give the same response in hemoglobin or hematocrit. The RBVs ± 95% confidence limits, calculated on the basis of final hemoglobin levels and hematocrit values, were respectively: freeze-dried ground beef, 56 ± 7 % and 62 ± 7 %; fortified textured defatted soy flour product, 81 ± 10 % and 79 ± 10 %; 2.3:1 (w/w) mixture of freeze-dried ground beef and soy flour product, 65 ± 6 % and 68 ± 6 %. The RBVs obtained for the iron in beef and for that in the soy flour product suggest that the anemic rat might not be a suitable model for normal man when screening such foods for their available iron. In normal man, the absorption of the iron in beef is comparable to that of inorganic reference iron, while that in textured soy flour is about one third. / Land and Food Systems, Faculty of / Graduate

A dissertation submitted to the faculty of Engineering, University of the Witwatersrand, in fulfillment of the requirements for the degree of Master of Science in Engineering. / The role of chromite dissolution in the smelting of ferrochromium was investigated with the object of improving the throughput and chromium recovery of the process. The solubility of a typical Transvaal chromite in silicate slags with cao/si02 ratios from 0,03 to 0,55 at 1550·C and 1650·C was determined. Synthetic slags were melted in porous chromite crucibles and the slag underwent repeated reactions with the chromite grains as it penetrated the crucible wall. Finally the slag came into equilibrium with -''the ,original chromite towards the outer part of the crucible wall. Microprobe analysis of this slag yielded the maximum or saturated solubilities of the chromite constituents in the slag. The solubility of cr203 was found to be low (-1 per cent) while the remaining components' solubilities (A1203 -16 per cent, FeO)T 12 per cent and MgO-8 per cent) were significantly higher. CaO/Sio2 ratios greater than 0,1 lowered the solubility of Mg0 significantly (e.g. from 14,1 per cent to 5,8 per cent at 1650·C). The complete dissolution of this chromite in these slags requires the slag to contain less than the solubility limits of each of these species simultaneously. It was recommended that the best way to achieve this in practice would be a well-stirred slag bath containing suspended carbon particles, in which a cao/Sio2 ratio of less -than 0,1 was maintained. Further work to investigate the effect of slag composition (including Na20 and CaF2) on the kinetics of chromite reduction in such a system was recommended. / AC 2018

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