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  • Author or Editor: R. Bezerra x
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Abstract

Mangroves are dynamic ecosystems due to influence of abiotic and biotic factors, but the latter are far less studied. Interactions between key invertebrate groups, trees, and soil properties, among others, determine the community structure throughout mangrove stand developing. Covariation among these factors, however, obscures their mutual relationships in shaping mangrove community assemblage patterns. In the estuary of Pacoti River (Ceará State, northeast Brazil), we compared the diversity and distribution of brachyurans and trees among several mid-littoral areas, and their relation with sediment features, to understand their relationships in community assemblage of new mangrove stands in developing. To discriminate the relation among these variables, ordination of data (PCA) and multivariate multiple correlation (PLS) were used. Data show that intertidal establishment of Brachyura was determined primarily by sediment properties, but further spatial distribution and diversity of this key faunal group, and the tree species that establishes, can influence each other. The prop roots habitat of Rhizophora mangle supports a higher brachyuran richness, since it allows the existence of multispecific crab burrow systems underground. Our results show that Rhizophora and brachyurans are key engineer organisms involved in shaping the physical and, hence, the ecological structure of newly established mangrove stands at Neotropics.

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Journal of Thermal Analysis and Calorimetry
Authors: D. Melo, G. Vicentini, L. Zinner, K. Zinner, H. de Souza, M. Batista, A. Garrido Pedrosa, and R. Bezerra

Abstract  

Complexes of neodymium and europium with amides and aminoxides were synthesized and characterized by complexometric analyses with EDTA, CHN microanalytical procedures, IR absorption spectra, absorption spectra of neodymium complexes, emission spectrum of europium compounds at 77 K, thermogravimetric analyses in N2 and differential scanning calorimetry (DSC) in N2. Infrared spectroscopy results revealed that the nitrate molecules are bound to the central ions as bidentate. Thermogravimetric plots indicated that the decomposition of the complexes occurs in the range 363-1163 K and resulted in the formation of Ln2O3 residues.

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Journal of Thermal Analysis and Calorimetry
Authors: Paula Nunes, Marília Bezerra, L. Costa, Juliana Cardoso, R. Albuquerque, M. Rodrigues, Gabriela Barin, Francilene da Silva, and A. Araújo

Abstract  

The purpose of this study was to evaluate the physical–chemical properties of collagen (CL) and usnic acid/collagen-based (UAC) films, using differential thermal analysis (DTA), thermogravimetry (TG/DTG), infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Both films were prepared by casting process using polyethylene glycol 1500 (PEG 1500) as plasticizer. In the spectrum of UAC, similar bands of the usnic acid are observed, indicating that the polymerization (film formation) did not affect the stability of the drug. Distinctly, DTA curve of UAC did not show an endothermic peak at 201 °C, indicative that the drug was incorporated into the polymeric system. These results were corroborated by the scanning electron microscopy (SEM). The TG/DTG curves of UAC presented a different thermal decomposition profile compared to the individual compounds and CL. These findings suggest the occurrence of molecular dispersion or solubilization of the drug in the collagen film.

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