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Structural study of a series of synthetic goethites obtained in aqueous solutions containing cadmium(II) ions

The capacity of goethite for Cd-II substitution has been explored in a series of synthetic samples prepared from Fe-III and Cd-II nitrate solutions aged 21 days in alkaline media. The total metal content ([ Fe] + [ Cd]) was 0.071 M in all preparations. The samples have been characterized by chemical and X-ray diffraction analysis; the morphology of the solids is described. The cell parameters for all samples were obtained by the Rietveld fits to the X-ray diffraction data. Refined structures show that for samples prepared at the final molar ratio mu(Cd)less than or equal to5.50 (expressed as mu(Cd) = 100X[Cd]/[Cd] + [Fe]), a (Cd, Fe)-goethite is the only crystalline product. In these samples, the unit cell parameters increased as a function of Cd concentration, indicating Cd incorporation in the structural frame. At the preparative ratio, mu(Cd)=7.03, the incorporation of Cd in the goethite structure is drastically reduced and a probable Cd-substituted hematite is formed together with the Fe,Cd-goethite. (C) 2003 International Centre for Diffraction Data.

Argentina: recent dynamics in the software and IT services industry

Includes bibliography.

Early Diagnosis of Regional Odontodysplasia in an Infant

Regional odontodysplasia is a rare and significant dental malformation. It is a dental alteration of unknown etiology, involving both mesodermal and ectodermal dental components, which present clinical, radiographic, and histologic features. This article reports a clinical case of a 10-month-old child who was diagnosed with regional odontodysplasia in the maxilla, confirmed by radiographic examination, with a follow-up of 5 years. The clinical, radiographic, and histologic features were reviewed.

Manchester, Chetham's Library MS 8009 (Mun. A.6.31): A Codicological Description

This article presents a complete codicological description of Manchester, Chetham's Library, MS 8009 (Mun.A.6.31), a late fifteenth-century production that contains a combination of secular and religious texts. The manuscript's significance for both the literary and textual scholar was recognized by Derek Pearsall when he suggested its suitability for a facsimile edition. The restrictions imposed by the Governors of the Library for reproduction under the present conditions, however, suggest that Pearsall's recommendation may have to wait for some time. The purpose of this paper is to fill that void by correcting some inaccuracies in previous descriptions and completing them with supporting visual evidence.

Measuring the geographic distribution of maternal education in Africa

Thesis (Master's)--University of Washington, 2016-08