Interaction of artesunate with β-cyclodextrin: Characterization, thermodynamic parameters, molecular modeling, effect of PEG on complexation and antimalarial activity

AbstractInclusion of artesunate in the cavity of β-cyclodextrin (β-CD) as well as its methyl and hydroxypropyl derivatives was investigated experimentally and by molecular modeling studies. The effect of PEG on the inclusion was also studied. A 1:1 stoichiometry was indicated by phase-solubility studies both in the presence and absence of PEG and suggested by the mass spectrometry. The mode of inclusion was supported by 2D NMR and results were further verified by docking studies utilizing Fast Rigid Exhaustive Docking acronym. The thermodynamic parameters were determined for both binary and ternary systems using solution calorimetry and were found to be best for the methyl-β-cyclodextrin (Me-β-CD) system. However, the presence of PEG improves the complexation ability as evident from elevation in the numerical value of the stability constant (K). Solubility and dissolution profile of binary complex is enhanced in the presence of PEG, which is approximately at par with drug Me-β-CD complexes. In vivo studies showed 100% survivability in artesunate–Me-β-CD complexes

Effect of niobium particulate addition on the microstructure and mechanical properties of pure magnesium

10.1016/j.jallcom.2011.10.019Journal of Alloys and Compounds513202-207JALC

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Not AvailableReleased during the Foundation Stone Laying Ceremony of Farm Office cum Field Laboratory on August 3, 2019Not Availabl

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Not AvailableDFR Extension Folder No.3Not Availabl

Formas de carbono em Latossolo Vermelho Eutroférrico sob plantio direto no sistema biogeográfico do cerrado Carbon forms of a Typic Eutroferric Red Latossol under no-tillage in a savanna biogeographic system

Este trabalho teve por objetivo avaliar aspectos da física, química e da dinâmica de carbono de um Latossolo Vermelho Eutroférrico, sob diferentes condições de uso. Foram utilizados materiais de solo cultivado com plantio direto, irrigado e sequeiro, e sob floresta nativa, na região de Santa Helena de Goiás (GO). As amostras foram coletadas de camadas de 0,00-0,05, 0,05-0,10, 0,10-0,20, 0,20-0,30 e 0,30-0,40 m e separadas em agregados maiores e menores que 0,25 mm. Foram realizadas análises químicas e físicas para caracterização do solo e determinados o carbono orgânico total, o carbono mineralizável, o carbono da biomassa microbiana, o carbono solúvel em água e a matéria orgânica lábil. Os resultados, indicaram que o plantio direto não foi capaz de manter os níveis de carbono nos agregados, quando comparado ao solo sob floresta nativa; a matéria orgânica desempenhou papel relevante na formação e estabilização de agregados maiores que 0,25 mm; a porosidade, resistência ao penetrômetro e densidade do solo demonstraram que houve aumento da compactação do solo no sistema plantio direto, quando comparado ao solo sob floresta nativa, tendo a densidade se mostrado uma variável satisfatória para a avaliação de compactação no Latossolo Vermelho Eutroférrico; a matéria orgânica lábil apresentou potencial para ser utilizada em estudos de ciclagem de nutrientes e fenômenos de dispersão e floculação de argila.<br>The objective of this study was to evaluate physical and chemical soil properties and organic carbon dynamics in a Typic Eutroferric Red Latossol under different land uses (no-till system, irrigated and non- irrigated crops, and native forest) in the savanna region of Santa Helena de Goiás, Goiás State, Brazil. Samples were collected from five soil layers (0.0-0.05, 0.05-0.10, 0.10-0.20, 0.20-0.30, and 0.30-0.40 m) and separated in aggregate size groups of above or below 0.25 mm. Chemical and physical analyses determined the total organic, mineralizable, microbial biomass, and water-soluble carbon, as well as the labile organic matter for soil characterization. The following conclusions were drawn: (a) carbon levels in the aggregates were lower in the no-till system compared to the soil under natural forest; (b) organic matter plays a relevant role in the genesis and stabilization of aggregates > 0.25 mm; (c) compared to the soil under natural forest, an increased soil compaction was evidenced in the no-till system by the porosity, resistance to penetrometer, and bulk density; (d) and soil density is a satisfactory variable to evaluate soil compaction of the Typic Eutrofic Red Latosol. Labile organic matter has the potential to be used in studies of clay dispersion and flocculation phenomena besides nutrient cycling