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    Elemental composition of Southeastern Anatolia asphaltites (Turkey) as a function of particle size
    (Estonian Academy Publishers, 2003) Hamamci, C; Düz, MZ; Saydut, A; Merdivan, M
    Elemental composition of asphaltites from Southeastern Anatolia was determined after grinding the samples and separating particles obtained into fractions by sieving. The total content of carbon, hydrogen, nitrogen and sulfur was highest in Halbur asphaltite where they were present over a wide size range (from 125 to 600 mum). The content of nitrogen, the least element in asphaltites, did not depend on grain size, whereas the carbon and sulfur concentrations increased with increasing size.
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    The preventive effect on bone loss of 50-Hz, 1-mT electromagnetic field in ovariectomized rats
    (Springer-Verlag Tokyo, 2002) Sert, C; Deniz, M; Düz, MZ; Aksen, F; Kaya, A
    Osteoporosis is a common health problem, especially in the elderly and in women after menopause. Although there are some treatment methods, they impose serious side effects. Recently, the use of an electromagnetic field (EMF) has been a promising candidate for better treatment of osteoporosis. In the present study, we investigated the preventive effects of low-frequency (50 Hz), low-intensity (1 mT), and long-term (6 weeks) EMF on bone loss in ovariectomized rats. We used 18 female albino Wistar rats (8 unexposed and 10 exposed) to assess the effect of EMF. We examined the mineralization and the morphology of the tibia in control and EMF-exposed rats. The cortical thickness of the tibia was increased in EMF-exposed rats (P < 0.002). The levels of Na and K in the tibia were significantly increased in rats exposed to EMF (P < 0.001; P < 0.002, respectively). We also observed an increased blood alkaline phosphatase (ALP) level after EMF exposure (P < 0.05). No significant differences in the levels of Ca, Mg, Li, or creatine were found between the exposed and unexposed groups. Our data support the notion that an EMF may prove to be an effective treatment method for osteoporosis and other abnormalities related to bone loss.
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    The role of trace minerals in the pathogenesis of postmenopausal osteoporosis and a new effect of calcitonin
    (Springer Japan Kk, 2002) Gür, A; Çolpan, L; Nas, K; Çevik, R; Saraç, J; Erdogan, F; Düz, MZ
    The physiologic role of calcitonin in mineral and bone homeostasis is not very well understood. Very few longitudinal studies have reported the effects of calcitonin therapy on trace minerals in postmenopausal osteoporosis despite the documented involvement of trace minerals in normal skeletal metabolism. Several trace minerals, particularly magnesium (Mg) and zinc (Zn), essential for organic bone matrix synthesis have been known for at least three decades. The present study was designed to determine whether the mineral profile was different between 70 osteoporotic and 30 nonosteoporotic postmenopausal women and to evaluate the efficacy of calcitonin therapy for 6 months on these trace minerals in postmenopausal osteoporotic women. In our study, the serum values of Mg, copper (Cu), and Zn (P < 0.05) were significantly lower in the patient group than those in the control group. After 3 months of treatment, serum Cu, Zn, and Mg levels did not differ between the patients and controls, and this situation has continued after the end of 6 months of therapy. Serum Cu, Zn, and Mg levels increased consistently during the 6-month treatment period. The higher levels of serum Mg in the 3rd and 6th months of therapy were found to be statistically significant compared to those before treatment (P < 0.05). Serum Cu and Zn levels were found to be significantly higher at all measurements during the treatment period as well as at the end of therapy (P < 0.05). These results suggest that (1) calcitonin therapy regulates Mg, Cu, and Zn levels in postmenopausal osteoporosis; (2) when serum calcium and phosphorus were normal in postmenopausal osteoporosis, serum Mg, Cu, and Zn were more useful for evaluation, and (3) further studies are essential to evaluate the role of dietary composition on the manifestations of osteoporosis.
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    Sorption behaviour of uranium(VI) with N,N-dibutyl-N?-benzoylthiourea Impregnated in Amberlite XAD-16
    (Elsevier Science Bv, 2001) Merdivan, M; Düz, MZ; Hamamci, C
    The sorption of U(VI) by N, N-dibutyl, N'-benzoylthiourea (DBBT) impregnated resin has been studied. DBBT impregnated resin was prepared by direct adsorption of chelating ligand onto macroporous support, Amberlite XAD-16. The adsorption of DBBT on the macroporous support is shown by FTIR spectroscopy to be the result of only weak chelating ligand-support interactions. Parameters such as the pH effect on the sorption of uranium, the sorption capacity of the impregnated resin, the stripping of uranium and the effect of coexisting ions were investigated by batch experiments. The results demonstrated that uranium(VI) ions, at pH 4.5-7 could be sorbed completely using 0.1 g Amberlite XAD-16 resin loaded with DBBT. The sorption capacity of the impregnated resin is 0.90 mmol uranium(VI) g(-1). Quantitative recovery of U(VI) is achieved by stripping with 0.1 M HNO3. The method was applied to the determination of uranium in synthetic samples. The precision of the method was 2.4 RSD% in a concentration of 1.20 mug ml(-1) for ten replicate analysis. (C) 2001 Elsevier Science B.V. All rights reserved.