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Solid-state reactions of Y2O3, BaCO3, and CuO mixtures at stoichiometric ratios of YBa4Cu6Ox reveal superconducting products having quite interesting and unusual properties. For instance, superconducting transition Tc at 90 K even without annealing in oxygen flow could be observed. Existence of a ferromagnetic-like behavior was recognized at low temperatures and magnetic fields greater than 1 T. Critical current densities are higher than the one expected from a polycrystalline superconductor. In addition, intergranular Jct-values obtained from the transport measurements show strong magnetic field dependency. Magnetic fields of ∼6.4 Oe decrease Jct by about 62% in magnitude. These materials seem to be good candidate for a low field sensor in superconducting gaussmeters.

Aim: To evaluate the effects of different regimens of hormone replacement therapy (HRT) on mammographic breast density. Methods: Mammograms of 113 healthy postmenopausal women who were on different HRT regimens were evaluated retrospectively. All women had a baseline mammography and at least one mammogram after at least 12 months of HRT. Four parenchymal patterns were considered mammographically. Quantification of density changes that occurred on follow-up mammograms was done qualitatively and with reference to densities on baseline mammograms. Results: Sixty women were treated with a continuous estrogen-progestin combination; 16 with a cyclic estrogen-progestin combination and 37 were with estrogen only. Twenty-six women had increased mammographic density after HRT. Mammographic density increase was detected in 23 women (38.3%) of the continuous estrogen-progestin combination group, two women (12.5%) of the cyclic estrogen-progestin combination group and one woman (2.7%) of the estrogen-only group. Mammographic density increase was more common among women in the continuous estrogen-progestin combination group than the other groups and this difference was found to be statistically significant (P

Y—Ba—Cu—O superconductors with a transition temperature of above 90 K are synthesized without the necessity of any thermal treatment under oxygen from mixtures of Y2O3, BaCO3, and CuO at a nominal composition of YBaCu2Ox (900—1000 °C, 20 h).

In the present work, the magnetic properties and the phase composition of barium ferrite BaFe12O19 powders prepared by the ammonium nitrate melt technique with Fe/Ba ratios varying from 2 to 13 was investigated. We observed that BaFe2O4 phase is formed at low values of Fe/Ba ratios (2-6) and alpha-Fe2O3 phase is formed at high values of Fe/Ba ratio as secondary phases. BaFe2O4 phase could be easily eliminated from the structure by washing the annealed powders with diluted HCI.HCI-washing is not effective for the elimination of alpha-Fe2O3 phase. Consequently, we succeed to obtain high quality single phase BaFe12O19 Powders at low Fe/Ba ratios. Highest specific saturation magnetization M, of the powders with Fe/Ba ratio of 2 was determined to be 66.7 emu/g. (c) 2006 Elsevier B.V. All rights reserved.