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Abstract  

Composites of poly(vinyl pyrrolidone)/hydroxyapatite (PVP/HA), at variable proportions (100/0; 80/20; 50/50; 20/80 wt%) were prepared and characterized by Fourier transformer-infrared spectroscopy (FT-IR), wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and thermogravimetry/differential thermogravimetry (TG/DTG). PVP carbonyl stretching was slightly shifted to lower frequency in composites indicating the formation of hydrogen bonding with HA hydroxyl groups. At the first cycle of heating, the calorimetric curves revealed a broad peak the intensity of which was reduced insofar as the amount of PVP decreased in the composites. This peak was attributed to the PVP enthalpy relaxation. According to the TG/DTG curves, PVP degraded into two steps sharply perceivable in the composites. The first decay was ascribed to the release of the pyrrolidone pendant groups and the following one concerned the burning of the hydrocarbon chains. The HA molecules seem to exert a catalytic action on the PVP degradation.

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Journal of Thermal Analysis and Calorimetry
Authors: G. Bannach, A. Siqueira, E. Ionashiro, E. Rodrigues, and M. Ionashiro

Abstract  

Solid-state M-2-Cl-BP, where M stands for Mn, Fe, Co, Ni, Cu, Zn and Pb and 2-Cl-BP is 2-chlorobenzylidenepyruvate, have been synthesized. Thermogravimetry and derivative thermogravimetry (TG/DTG), simultaneous thermogravimetry and differential thermal analysis (TG-DTA), X-ray powder diffractometry, infrared spectroscopy, elemental analysis, and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal stability and thermal decomposition of the isolated compounds.

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Solid-state 2-methoxybenzoates of light trivalent lanthanides

Synthesis, characterization and thermal behaviour

Journal of Thermal Analysis and Calorimetry
Authors: A. Siqueira, G. Bannach, E. Rodrigues, C. Carvalho, and M. Ionashiro

Abstract  

Solid-state LnL3 compounds, where L is 2-methoxybenzoate and Ln is light trivalent lanthanides, have been synthesized. Thermogravimetry (TG), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy and elementary analysis were used to characterize and to study the thermal behaviour of these compounds. The results led to information on the composition, dehydration, thermal stability and thermal decomposition of the isolated compounds. On heating these complexes decompose in three (Ce, Pr) or five (La, Nd, Sm) steps with the formation of the respective oxide: CeO2, Pr6O11 and Ln2O3 (Ln=La, Nd, Sm) as final residues. The theoretical and experimental spectroscopic study suggests predominantly the ionic bond between the ligand and metallic center.

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Abstract  

Solid-state Ln–L compounds, where Ln stands for heavy trivalent lanthanides or yttrium (III) (Tb–Lu, Y) and where L is pyruvate, have been synthesized. Thermogravimetry and derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), X-Ray powder diffractometry, infrared spectroscopy, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal behaviour, ligand denticity of the isolated complexes.

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Abstract  

Solid-state Ln(Bz)3·H2O compounds where Ln stands for trivalent yttrium or lanthanides and Bz is benzoate have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), X-ray powder diffractometry, infrared spectroscopy and chemical analysis were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal stability and thermal decomposition of the isolated compounds.

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Abstract  

Solid-state Ln(L)3 compounds, where Ln stands for trivalent Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y and L is 2-methoxybenzoate have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results provided information on the composition, dehydration, coordination mode, structure, thermal behaviour and thermal decomposition.

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Journal of Thermal Analysis and Calorimetry
Authors: E. Ionashiro, G. Bannach, A. Siqueira, C. de Carvalho, E. Rodrigues, and M. Ionashiro

Abstract  

Solid-state Ln(2-MeO-BP) compounds, where Ln stands for trivalent Eu to Lu and Y(III) and 2-MeO-BP (which is 2-methoxybenzylidenepyruvate) have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffraction, infrared spectroscopy and other methods of analysis were used to characterize and to study these compounds. On the base of the obtained results an Ln(2MeO-BP)3·nH2O general formula can be established.

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Summary  

A simple, selective and sensitive method was developed based on electrothermal atomic absorption spectrometry using Zeeman correction for quantitation of lead, in 100 ml of whole blood sample, as biological indicator for occupational exposure. Confidence parameters and stability of samples were considered. Ashing and atomization temperatures, considered critical, were 700 °C and 1,700 °C, respectively. The levels found during the validation process showed good sensitivity linearity, recovery, precision and accuracy. The stability results presented levels remaining constant for a 15 months period. The variations were not higher than 15% when comparing concentrations in zero time to those obtained after storage period.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: D. Cardoso, R. Rodrigues, V. Toledo, T. Moraes-Santos, V. Cardoso, and E. Nunan

Abstract  

F(ab’)2 is the fragment involved in the immunotherapy for scorpion stings and it would be convenient to label it with 99mTc for organ distribution and pharmacokinetics studies. The aim of the present study was to label scorpion antivenom F(ab’)2 with 99mTc keeping its biological activity, integrity and stability. High labeling yield was obtained using stannous chloride and sodium borohydride. Stability, immunoreactivity and integrity of 99mTc-F(ab’)2 was preserved. It was not observed any difference between potencies of unlabeled and labeled antivenom. 99mTc-F(ab’)2 can be a useful tool for use in biodistribution and pharmacokinetics studies on the evaluation of the efficacy of the antivenom against scorpion envenomation.

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