The use of L X-ray fluorescence for the determination of the concentration of Pb in human bone has been reported in the literature. A critique of the utility of the method and the shortcomings as an analytical approach in the evaluation of human exposure to Pb are addressed.
Thermal decomposition of Fc4Sn3Br166H2O was investigated by thermogravimetry. The decomposition products were characterized by U.V.-Visible spectroscopy, chemical analysis and X-ray diffraction. The TG curve of the complex showed three decomposition steps. In the first, a mixture of HBr and H2O was evolved. A ferricinium tin bromide compound (Fc4SnBr8) was found to sublime in the second step, whereas a mixture of HBr and H2O was given off in the third, leaving SnO2 as the residue, The stoichiometry of the thermal decomposition of [Fc4Sn3Br16 6H2O] has been established and a possible mechanism for its decomposition is suggested.
Authors:M. W. Abbasi, M. Q. Khan, M. J. Zaki, S. S. Shaukat, A. Rauf, N. Ahmed, M. Azeem and M. Tariq
Bacillus thuringiensis (B.t) is well known for its biocontrol potential against a variety of insects. Nematicidal potential of ten B.t isolates was tested against root-knot nematodes (Meloidogyne javanica (Treub) Chitwood) in vitro, under greenhouse as well as in field conditions. Eggs and second stage juveniles (J2) were exposed to 5 and 25% concentrations of bacterial cell-free aqueous extracts up to 96 h. B.t isolates showed lesser degrees of nematicidal activity at 5% concentration. However, some B.t isolates (B.t-14, B.t-16 and B.t-64) greatly reduced egg hatching and increased J2. All B.t isolates revealed suppressed egg hatching and increased mortality of J2 at 25% concentration. Soil applications with most of the B.t isolates under greenhouse and field conditions significantly improved height and fresh weights of root-knot nematode parasitized okra (Abelmoschus esculentus (L.) Moench). Some isolates, including B.t-64 reduced the number of galls and egg masses. B.t-64 reduced gall formation up to 70% under greenhouse conditions. However, 29% of decrease was observed in field conditions. Similarly, B.t-64 treated plants showed a 56% decreased in eggs/egg mass in a field experiment. Population of root-knot nematodes in the rhizosphere was decreased up to 61% in the field experiment as compared to control.