Instrumental neutron activation analysis of blood serum

Instrumental neutron activation analysis has been used to determine 15 trace elements in twelve blood serum samples taken from healthy students at Bilkent University in Ankara. The method allowed the determination of Sc, Cr, Mn, Fe, Co, Zn, Se, Rb, Cs, Ce, Eu, Tb, Hf, Ta and Hg, which occur at the μg.ml-1 to ng.ml-1 levels. There are no values reported for Tb, Hf, Ce, Eu and Ta before. The other results are compared with the values reported in the literature. Most are in the range of the reported values except for Fe, Zn, Se and Cs. © 1995 Akadémiai Kiadó

A novel method to detect unlabeled inorganic nanoparticles and submicron particles in tissue by sedimentation field-flow fractionation

A novel methodology to detect unlabeled inorganic nanoparticles was experimentally demonstrated using a mixture of nano-sized (70 nm) and submicron (250 nm) silicon dioxide particles added to mammalian tissue. The size and concentration of environmentally relevant inorganic particles in a tissue sample can be determined by a procedure consisting of matrix digestion, particle recovery by centrifugation, size separation by sedimentation field-flow fractionation (SdFFF), and detection by light scattering

Radiochronology of sediments from the Mediterranean Sea using natural210Pb and fallout137Cs

The210Pb and137Cs profiles of sediment cores from two locations in southern Spain, three locations in southern Turkey and two locations in northern Cyprus were determined by direct γ-ray spectroscopy. Sedimentation rates were derived for all locations using the210Pb data. The rates range from 1.39±0.12 cm · y-1 (0.50±0.04 g · cm-2 · y-1) to 0.08±0.01 cm · y-1 (0.039±0.003 g · cm-2 · y-1). Except for one core, the137Cs profiles were also used to compute sedimentation rates. The results are in good agreement with those of210Pb values. The results of the Constant Initial Concenration and Constant Rate of Supply dating models are in good agreement with each other. The flux of unsupported210Pb varies between 0.11±0.03 to 0.74±0.01 pCi · cm-2. The average depositional flux was found to be considerably lower for cores from the Eastern Mediterranean. © 1994 Akadémiai Kiadó

Soil colloid analysis by flow field-flow fractionation

David J. Chittleborough, Soheyl Tadjiki, James F. Ranville, Finlay Shanks and Ron Becket

Determination of thickness, aspect ratio and size distributions for platey particles using sedimentation field-flow fractionation and electron microscopy

Sedimentation field-flow fractionation (SdFFF) can be used to prepare fractions of very narrow mass range for electron microscopic (EM) analysis. Assuming the particle density is the same for all particles within that fraction the equivalent spherical diameter for the particles can be calculated from SdFFF theory. Integration of the micrograph image of each particle yields an area measurement which, when used in conjunction with the equivalent spherical particle diameter (from SdFFF), provides information about the particle thickness and aspect ratio. Thus SdFFF-SEM can be used to provide detailed information about clay morphology across the particle size distribution of the sample. Three clay minerals have been studied using the methodologies outlined in this paper. The aspect ratio for the Purvis School Mine kaolinite ranged from 2.8-5.9, for RM30 illite from 11.3-24.3, and for Muloorina illite from 3.1-4.3.Ronald Beckett, Deirdre Murphy, Soheyl Tadjiki, David J. Chittleborough and J. Calvin Gidding