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O. Gonzalez‐Fernandez M. J. Batista M. M. Abreu I. Queralt M. L. Carvalho 《X射线光谱测定》2011,40(5):353-363
The chemical concentrations of 11 elements in 6 species of edible plants grown in 7 soils, developed in different gossanous materials of the abandoned mine area of Sao Domingos, in southern Portugal, was measured by energy dispersive X‐ray fluorescence. The total fraction of elements in the soils from which the plants were sampled, was measured, using wavelength dispersive X‐ray fluorescence. The elemental content in bioavailable fraction was obtained by using three different leaching tests: DIN 38414‐S4, 1 M ammonium acetate and 0.005 M DTPA. Leachates were analyzed by Induced Coupled Plasma—Optical Emission Spectrometer (ICP‐OES) and Induced Coupled Plasma—Mass Spectrometer (ICP‐MS). The mineralogy of the same soils was evaluated by X‐ray diffraction to identify the species present. The results show that levels in plants can be hazardous especially for Pb and As. Important concentrations of Fe and K were also observed. A different uptake was observed in the several plants for the different elements. The highest assimilation of metals was observed in sampling points containing soluble sulfate salts. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Marie Huynh Maxime De Abreu Prof. Dr. Philippe Belmont Dr. Etienne Brachet 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(11):3581-3607
Rearrangement reactions are certainly one of the most useful approaches towards complex structures in organic chemistry. With efficient conditions, it is indeed possible to convert simple substrates into highly functionalized products. Moreover, combining this approach with an attractive initiation process, such as visible-light catalysis, makes these reactions particularly powerful. Recently, tremendous improvements have been made, owing to a better understanding of photoredox mechanisms. In this review, recent progress on visible-light aryl migration reactions is discussed, focusing especially on Smiles rearrangement and related reactions. 相似文献
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Mosbah Habib Chahdoura Hassiba Mannai Asma Snoussi Mejdi Aouadi Kaïss Abreu Rui M. V. Bouslama Ali Achour Lotfi Selmi Boulbaba 《Applied biochemistry and biotechnology》2019,187(3):1113-1130
Applied Biochemistry and Biotechnology - A series of enantiopure isoxazolidines (3a–c) were synthesized by 1,3-dipolar cycloaddition between a (−)-menthone-derived nitrone and various... 相似文献
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In this Letter we construct non-Abelian field theories employing the Faddeev-Jackiw symplectic formalism. The original Abelian fields were modified in order to introduce the non-Abelian algebra. We construct the SU(2) and SU(2)⊗U(1) Yang-Mills theories having as starting point the U(1) Maxwell electromagnetic theory. 相似文献
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In this paper we study existence and properties of solutions of the problem Δw=0 on the half-space with nonlinear boundary condition ∂w/∂η+w=|w|p−2w where 2<p<2(N−1)/(N−2) and N?3. We obtain a ground state solution w=w(x1,…,xN−1,t) which is radial and has exponential decay in the first N−1 variables. Moreover, w has sharp polynomial decay in the variable t. 相似文献
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In the first part of this paper, we share and elucidate the way we mobilize histories in some disciplines that are part of the undergraduate courses in mathematics teacher education offered by State University of Campinas and Federal University of Rio Grande do Norte in Brazil. This way of mobilization can be featured as a set of collective indisciplinary problematizations occurring in a series of student investigations. Mobilizing practices of mathematics culture are the object of these investigations. These practices are performed by different communities both constituted by and constituent of different human activities. In the second part of this paper, we will discuss our way of mobilizing histories, contrasting it with the theoretical perspective of expansive learning, just as it has been defended by Yrjö Engeström, in his article Non scolae sed vitae discimus—towards overcoming the encapsulation of school learning. We will also attempt to highlight the role which this researcher has attributed to history in his model of expansive learning, a perspective based on the current research on activity theory. 相似文献
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Lucas M. Abreu Richard K. Phipps Charlotte H. Gotfredsen Thomas O. Larsen 《Tetrahedron letters》2010,51(13):1803-3363
Cytosporones O, P and Q, together with the known compounds cytosporones B, C, D, E and dothiorelones A, B, C, and H were isolated from the ascomycete fungus Cytospora sp. during a chemotaxonomic study of fungal endophytes belonging to the related genera Cytospora and Phomopsis from Brazil. The structures were determined by NMR spectroscopy and mass spectrometry. With exception of cytosporones D, E, Q, and dothiorelone B, all compounds were consistently detected in the metabolite profiles of eight Cytospora isolates investigated; and were also produced by a distinct chemotype of Phomopsis. 相似文献