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Abstract  

A simple and efficient method to isolate228Ra from natural thorium oxalate was developed. It consists in the coprecipitation of radium by hydrolysis of saturated solutions of ammonium thoroxalate followed by ion-exchange chromatography on Amberlite IR-120. The final product is carrier-free and pure enough for the preparation of thin sources for alpha and conversion electrons spectrometry. The radium coprecipitation utilized in the first step of this method, could be used to separate thorium from most of its radioactive daughters, decreasing the hazards of manipulation of large quantities of thorium.

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Abstract  

This study aimed to evaluate minor and trace elements in the water during different water purification steps of a deionized water production plant, located at CENA, by total-reflection X-ray fluorescence (TXRF) technique, using Ga as internal standard for elemental quantification. This approach was capable of determining Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, As, Se, Br, Rb at concentrations higher than 40–100 μg L−1, and for K, Ca, Sc, Ti, V and Sr at concentrations higher than sub mg L−1 in the water samples. TXRF spectrometer encompasses an X-ray tube with a Mo target with a Zr filter. The elemental characteristic X-rays were recorded by a Si(Li) semiconductor detector and the X-ray spectra deconvoluted by AXIL software.

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Thermal study of cyclopalladated complexes of the type [Pd2(dmba)2X2(bpe)]

(X=NO- 3, Cl-, N- 3, NCO-, NCS-; bpe=trans-1,2-bis(4-pyridyl)ethylene)

Journal of Thermal Analysis and Calorimetry
Authors: E. T. de Almeida, A. M. Santana, A. V. G. Netto, Claudia Torres, and A. E. Mauro

The synthesis, characterization and thermal analysis of the novel cyclometallated compounds [Pd2(dmba)2Cl2(μ-bpe)] (1), [Pd2(dmba)2(N3)2(μ-bpe)] (2), [Pd2(dmba)2(NCO)2(μ-bpe)] (3), [Pd2(dmba)2(SCN)2(μ-bpe)] (4), [Pd2(dmba)2(NO3)2(μ-bpe)] (5) (bpe=trans-1,2-bis(4-pyridyl)ethylene; dmba=N,N-dimethylbenzylamine) are described. The thermal stability of [Pd2(dmba)2X2(μ-bpe)] complexes varies in the sequence 1>4>3>2>5. The final residues of the thermal decompositions were characterized as metallic palladium by X-ray powder diffraction.

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Abstract

Palladium(II) coordination compounds of general formula trans-[PdX2(isn)2], X = Cl (1), N3 (2), SCN (3), NCO (4), isn = isonicotinamide; were synthesized and characterized in solid state by elemental analysis, infrared spectroscopy, and simultaneous TG–DTA. TG experiments reveal that the compounds 14 undergo thermal decomposition in three or four stages, yielding Pd0 as final residue, according to calculus and identification by X-ray powder diffraction.

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Journal of Thermal Analysis and Calorimetry
Authors: A. V. G. Netto, A. M. Santana, A. E. Mauro, Regina C. G. Frem, E. T. de Almeida, M. S. Crespi, and H. E. Zorel Jr.
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Journal of Thermal Analysis and Calorimetry
Authors: Sahra C. Lemos, Silmar J. S. Franchi, Adelino V. G. Netto, Antonio E. Mauro, Oswaldo Treu-Filho, Regina C. G. Frem, Eduardo Tonon de Almeida, and Cláudia Torres

Abstract

This work describes the synthesis, characterization, and the thermal behavior investigation of four palladium(II) complexes with general formulae [PdX2(mba)2], in which mba = N-methylbenzylamine and X = OAc (1), Cl (2), Br (3) or I (4). The complexes were characterized by elemental analysis, infrared vibrational spectroscopy, and 1H nuclear magnetic resonance. The stoichiometry of the complexes was established by means of elemental analysis and thermogravimetry (TG). TG/DTA curves showed that the thermodecomposition of the four complexes occurred in 3–4 steps, leading to metallic palladium as final residue. The palladium content found in all curves was in agreement with the mass percentages calculated for the complexes. The following thermal stability sequence was found: 3 > 2 > 4 > 1. The geometry optimization of 1, 2, 3, and 4, calculated using the DFT/B3LYP method, yielded a slightly distorted square planar environment around the Pd(II) ion made by two anionic groups and two nitrogen atoms from the mba ligand (N1 and N2), in a trans-relationship.

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Journal of Thermal Analysis and Calorimetry
Authors: Ellen Denise P. Almeida, Adjane A. Costa, Mairim R. Serafini, Fábia C. Rossetti, Juliana M. Marchetti, Victor Hugo V. Sarmento, Rogéria de S. Nunes, Mário Ernesto G. Valerio, Adriano A.S. Araújo, and Ana Amélia M. Lira

Abstract

Solid lipid nanoparticles (SLN) without drug and SLN loaded with chloroaluminum phthalocyanine (AlClPc) were prepared by solvent diffusion method in aqueous system and characterized by thermal analyses and X-ray diffraction (XRD) in this study. Determination of particle size, zeta potential (ZP), and encapsulation efficiency were also evaluated. SLN containing AlClPc of nanometer size with high encapsulation efficiency and ZP were obtained. The results indicated that the size of SLN loaded with AlClPc is larger than that of the inert particle, but ZP is not changed significantly with incorporation of the drug. In differential scanning calorimetry (DSC) curves, it was observed that the melting point of stearic acid (SA) isolated and in SLN occurred at 55 and 64 °C, respectively, suggesting the presence of different polymorphs. DSC also shows that the crystallinity state of SLN was much less than that of SA isolated. The incorporation of drug in SLN may have been favored by this lower crystallinity degree of the samples. XRD techniques corroborated with the thermal analytic techniques, suggesting the polymorphic modifications of stearic acid.

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