Nordin BEC, Wilkinson, R, Marshall DH, Gallagher JC, Williams A, Peacock M. Calcium Absorption in the elderly. In Nielsen SP, Hjorting-Hansen E, editors. Calcified Tissues 1975. Copenhagen: FADL Publishing, 1975, p. 442-451.
Studies with elderly subjects have shown a significant and progressive fall in calcium absorption with age. Two possible explanations are vitamin D deficiency and acquired "resistance" to vitamin D associated with impaired hydroxylation of 25-hydrocholecalciferol to 1,25-dihydroxycholecalciferol. Data indicate the first appears more likely below 70 years of age, the second more likely a factor after 70. Impaired renal function may be a factor in calcium malabsorption.
Wilcox MF, Koch JG. A freshman laboratory program without chromium. J Chem Educ. 1993:70(6):474-475.
Discusses the problems faced by the Ithaca College chemistry courses that used chromiumVI compounds, classified by Occupational Safety and Health Administration as carcinogenic, and the strategy used to preserve "the solid pedagogy" provided by chromium experiments. Provides two more environmentally benign complexes to replace chromium acac. Also gives experimental details for the following: preparation of tris(Acetylacetonato)manganese(III), colormetric analysis of Mn(C5H7O2)3, preparation of tris(Acetylacetone)iron(III), and titimetric analysis of Fe(C5H7O2)3.