Catalysis to discriminate single atoms from subnanometric ruthenium particles in ultra-high loading catalysts

We report a procedure for preparing ulta-high metal loading (10-20 % w/w Ru) Ru@C60 nanostructured catalysts comprising exclusively Ru single atoms. We show that by changing the Ru/C60 ratio and the nature of the solvent used during the synthesis, it is possible to increase the Ru loading up to 50% w/w, and to produce hetero-structures containing subnanometric Ru nanoparticles. Several techniques such as high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy – high angle annular dark field (STEM-HAADF), Raman spectroscopy, wideangle X-ray scattering (WAXS), extended X-ray absorption fine structure (EXAFS) and X-ray photoelectron spectroscopy (XPS) together with theoretical calculations were used to characterize these materials. At such high metal loading, the distinction between Ru single atoms and clusters is not trivial, even with this combination of techniques. We evaluated the catalytic properties of these materials for the hydrogenation of nitrobenzene and 2,3-dimethyl-2-butene. The catalysts containing only Ru single atoms are much less active for these reactions than the ones containing clusters. For nitrobenzene hydrogenation, this is because electro-deficient Ru single atoms and few atom Run clusters are not performant for H2 activation compared to larger clusters (n ≥ 13), as shown by density functional theory (DFT) calculations. For the more crowded substrate 2,3-dimethyl-2-butene, DFT calculations have shown that this is due to steric hindrance. These simple tests can thus been used to distinguish samples containing metallic sub-nanometer nanoparticles. These novel catalysts are also extremely active for the hydrogenation of -substituted 2,3-dimethyl-2-butene

Antischistosomal Activity of Trioxaquines: In Vivo Efficacy and Mechanism of Action on Schistosoma mansoni

Schistosomiasis is among the most neglected tropical diseases, since its mode of spreading tends to limit the contamination to people who are in contact with contaminated waters in endemic countries. Here we report the in vitro and in vivo anti-schistosomal activities of trioxaquines. These hybrid molecules are highly active on the larval forms of the worms and exhibit different modes of action, not only the alkylation of heme. The synergy observed with praziquantel on infected mice is in favor of the development of these trioxaquines as potential anti-schistosomal agents

Fe doping effects on the structural, magnetic, and magnetocaloric properties of nano-sized Pr0.6Bi0.4Mn1−x FexO3 (0.1 ≤ x ≤ 0.3) manganites

International audienceThe structural, magnetic, and magentocaloric properties are systematically investigated for Pr0.6Bi0.4Mn1−x Fe x O3 (0.1 ≤ x ≤ 0.3) manganites. The samples have been synthesized by sol–gel method. X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy were employed to investigate the crystalline structure. Magnetization measurements were used to investigate the magnetic properties. All the samples crystallize in the orthorhombic Pnma space group as expected for manganite compounds. The presence of a PrMn2O5 compound is also evidenced by XRD. The average size of the manganite particles is about 50–60 nm. Particle characterizations at the atomic level turn to be of paramount importance. Magnetic measurements versus temperature under an applied magnetic field of 0.01 T show that all samples exhibit a paramagnetic–ferromagnetic transition. Temperature-dependent magnetization measurements and Arrott analysis reveal second-first order ferromagnetic transitions for (x = 0.1 and x = 0.2). The magnetic entropy change |ΔS M| was estimated using Maxwell relation method and is found to reach maximum values of 0.47 and 0.37 J/kg/K under an applied magnetic field of 5 T for x = 0.1 and x = 0.2, respectively

A Escola de Enfermagem da Universidade de São Paulo e a reconfiguração da identidade profissional da Enfermagem Brasileira La Escuela de Enfermería de la Universidad de São Paulo y la reconfiguración de la identidad profesional de la Enfermería Brasileña The University of São Paulo, School of Nursing and the Brazilian Nursing professional identity reconfiguration

Este estudo pretende contribuir para a reflexão em torno das representações da identidade profissional da enfermagem brasileira. Para tanto, recupera o tema a partir de imagens construídas sobre a noção de identidade, profissionalização da enfermagem e os negros no Brasil. Considera-se que as representações da inferioridade nata, erigidas para os negros, favoreceram a exclusão de mulheres negras da formação profissional da enfermagem. Com base na análise histórica e documentação pertinente, preservada no Centro Histórico-Cultural da Enfermagem Ibero-Americana, em especial, as Fichas de Admissão, os resultados permitem afirmar que, a Escola de Enfermagem da Universidade de São Paulo propiciou a inclusão de homens e mulheres negras na enfermagem profissional redimensionando a identidade da enfermagem brasileira.<br>Este estudio pretende contribuir para la reflexión alrededor de las representaciones de la identidad profesional de la enfermería brasileña. Para tanto, se recupera el tema a partir de imágenes construidas sobre el concepto de identidad, profesionalización de la enfermería y los negros en Brasil. Considerase que las representaciones de inferioridad nativa, erigidas para los negros, favorecieran la exclusión de mujeres negras de la formación profesional de enfermería. Embasado en un análisis histórico y documentación pertinente, preservada en el Centro Histórico-Cultural de la Enfermería Ibero-Americana, en especial, los registros de Admisión, los resultados permiten afirmar que, la Escuela de Enfermería, de la Universidad de São Paulo ha favorecido la inclusión de hombres y mujeres negras en la enfermería profesional redimensionando la identidad de la enfermería brasileña.<br>This study intends to contribute for reflection around Brazilian nursing professional identity. For this purpose the subject was rescued from images built up on the knowledge related to identity, nursing professionalization and the blacks in Brazil. It is considered that representations of native inferiority, raised for blacks, have favored the exclusion of black women from the professional nursing education. Based on historical analysis and pertinent documentation, preserved at the Historical-Cultural Center for the Iberian-American Nursing, particularly the admittance forms, outcomes allow to state that the University of Sao Paulo, School of Nursing, has provided the inclusion of men and black women into the professional nursing, thus re-dimensioning the Brazilian Nursing identity