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Multilayers of bimetallic CoPd alloyed and assembled nanoparticles, prepared by room temperature sequential sputtering deposition on amorphous alumina, were studied by means of high-resolution transmission electron microscopy, x-ray diffraction, SQUID-based magnetometry and x-ray magnetic circular dichroism. Alloying between Co and Pd in these nanoparticles gives rise to a high perpendicular magnetic anisotropy. Their magnetic properties are temperature dependent: at low temperature, the multilayers are ferromagnetic with a high coercive field; at intermediate temperature the behavior is of a soft-ferromagnet, and at higher temperature, the perpendicular magnetic anisotropy in the nanoparticles disappears. The magnetic orbital moment to spin moment ratio is enhanced compared with Co bare nanoparticles and Co fcc bulk. The financial support of the Spanish MINECO MAT2011-23791, MAT2014-53921-R and Aragonese DGA-IMANA E34 projects is acknowledged.

Effect of sex chromosome complement on sodium appetite and Fos-immunoreactivity induced by sodium depletion. Am J Physiol Regul Integr Comp Physiol 306: R175–R184, 2014. First published November 20, 2013; doi:10.1152/ajpregu.00447.2013.—Previous studies indicate a sex chromosome complement (SCC) effect on the angiotensin II-sexually dimorphic hypertensive and bradycardic baroreflex responses. We sought to evaluate whether SCC may differentially modulate sexually dimorphic-induced sodium appetite and specific brain activity due to physiological stimulation of the rennin angiotensin system. For this purpose, we used the “four core genotype” mouse model, in which the effect of gonadal sex and SCC is dissociated, allowing comparisons of sexually dimorphic traits between XX and XY females as well as in XX and XY males. Gonadectomized mice were sodium depleted by furosemide (50mg/kg) and low-sodium diet treatment; control groups were administered with vehicle and maintained on normal sodium diet. Twenty-one hours later, the mice were divided into two groups: one group was submitted to the water-2% NaCl choice intake test, while the other group was perfused and their brains subjected to the Fos-mmunoreactivity (FOS-ir) procedure. Sodium depletion, regardless of SCC (XX or XY), induced a significantly lower sodium and water intake in females than in males, confirming the existence in mice of sexual dimorphism in sodium appetite and the organizational envolvement of gonadal steroids. Moreover, our results demonstrate a SCC effect on induced brain FOS-ir, showing increased brain activity in XX-SCC mice at the paraventricular nucleus, nucleus of the solitary tract, and lateral parabrachial nucleus, as well as an XX-SCC augmented effect on sodium depletion-induced brain activity at two circumventricular organs, the subfornical organ and area postrema, nuclei closely involved in fluid and blood pressure homeostasis. publishedVersion

Previous studies indicate a sex chromosome complement (SCC) effect on the Angiotensin II-sexually dimorphic hypertensive and bradycardic baroreflex responses. We sought to evaluate whether SCC may differentially modulate sexually dimorphic induced sodium appetite and specific brain activity due to physiological stimulation of the rennin angiotensin system. For this purpose, we used the "four core genotypes" mouse model, in which the effect of gonadal sex and SCC is dissociated, allowing comparisons of sexually dimorphic traits between XX and XY females as well as in XX and XY males. Gonadectomized mice were sodium depleted by furosemide (50 mg/kg) and low sodium diet treatment; control groups were administered the vehicle and maintained on normal sodium diet. Twenty-one hours later, the mice were divided into two groups: one was submitted to the water/NaCl 2% choice intake test, while the other was perfused and their brains subjected to the Fos-immunoreactivity (Fos-ir) procedure. Sodium depletion, regardless of genetic sex (XX or XY), induced a significantly lower sodium and water intake in females than in males, confirming the existence in mice of sexual dimorphism in sodium appetite and the organizational involvement of gonadal steroids. Moreover, our results demonstrate a SCC effect on induced brain Fos-ir, showing increased brain activity in XX-SCC mice at the paraventricular nucleus, nucleus of the solitary tract and lateral parabrachial nucleus, as well as an XX-SCC augmented effect on sodium-depletion induced brain activity at two circumventricular organs, the subfornical organ and area postrema, nuclei closely involved in fluid and blood pressure homeostasis. publishedVersion Fisiología (incluye Citología)

To investigate whether sex chromosome complement modulates bradycardic baroreflex response and contributes to the angiotensin II– bradycardic baroreflex sex differences, we used the four core genotype mouse model in which the effect of gonadal sex and sex chromosome complement is dissociated, allowing comparisons of sexually dimorphic traits among XX and XY females, as well as in XX and XY males. In conscious gonadectomized (GDX) MF1 transgenic mice we evaluated baroreflex regulation of heart rate in response to changes in blood pressure evoked by phenylephrine (1 mg/mL), angiotensin II (100g/mL), and sodium nitroprusside (1 mg/mL). The administration of phenylephrine in GDX-XY females resulted in a significantly lower baroreflex response when compared with the other genotypes (in beats min 1mm Hg1 [slopes of regression lines for GDX-XY females 3.560.37 versus 6.060.38, 6.370.54 and 6.700.34 for GDX-XY male, GDX-XX female, and GDX-XX male mice, respectively]) {F(1,19)9.63; P0.01}. In addition, in both GDX-XY males and females, the angiotensin II-bradycardic baroreflex response was attenuated when compared with heart rate changes in GDX-XX male and female mice (in beats min1 mm Hg1 [slopes of regression lines: 2.830.28 versus 5.760.26 in GDX-XY and GDX-XX mice, respectively]) {F(1,19)13.91; P0.005}. In contrast, reflex tachycardic responses to sodium nitroprusside were comparable in all of the genotypes. These data support the hypothesis that sex chromosome complement modulates reflex inhibition of heart rate to phenylephrine and angiotensin II. Elucidating the foundational sources of sexually dimorphic traits in the regulation of baroreceptor reflex may enable the design of more appropriate sex-tailored therapeutic treatments in the future. publishedVersion

The magnetic behaviour of ordered arrays of magnetic nanowires is controlled by the combined action of anisotropy energy terms determined by geometrical shape, crystalline structure and magnetostriction, as well as by the magnetostatic interactions among them. A number of works have been reported on the role of magnetostatic interaction in arrays of nanowires, sometimes focusing on nanowires with vanishing crystalline and magnetostrictive energy terms. Here, in turn we are interested in Co-base nanowires whose magnetocrystalline anisotropy plays a very important role. Arrays of Co-base nanowires offer novel, sometimes unexpected behaviour that is not fully understood. Such results are connected to their magnetocrystalline anisotropy, and to their complex magnetization reversal mode. Arrays of Co and Co-base nanowires have been fabricated by template-assisted method, by electroplating into highly ordered self-assembled pores of nanoporous alumina membranes. Their hcp or fcc crystal structure is confirmed to depend on length of nanowires as well as on the presence of selected elements in the composition. The magnetic behaviour of these arrays has been experimentally investigated as a function of (i) geometry (e.g. diameter and, particularly short length) and (ii) composition (e.g. adding Ni or Pd). A complementary study on its temperature dependence reveals the nature of the dominant anisotropy, while the angular dependence of hysteresis loops (e.g. coercivity and remanence) enables a deeper analysis of the magnetization reversal process. Micromagnetic reversal modes are reviewed and modelling and simulations procedures introduced. Complex rotational mechanisms are concluded to be responsible for the reversal process following micromagnetic modes distinct from those pure classically established. SEM image of an array of Co-base nanowires. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim., M. Vazquez is particularly honoured to contribute with this study in homage of Prof. Manfred Fahnle with whom he shared quite interesting discussions on phase transition in amorphous alloys already 30 years ago. The authors are very grateful to Dr O. Chubykalo-Fesenko and Dr R. Perez at the ICMM/CSIC, Madrid, to Dr V. Prida from University of Oviedo, and to Dr D. Altbir and Dr J. Escrig from the University of Santiago de Chile for their essential support and supply of results in the preparation of this feature article. The study has been supported by the Spanish Ministry of Science and Innovation under project MAT2010-20798-C05. L. G. Vivas acknowledges the International Iberian Nanotechnology Laboratory (INL) for the doctoral grant.

Síntesis y caracterización del material ternario Ag2SnSe3 dopado con galio. Pirela B., María E.; Velásquez Velásquez, Ana; Villarreal, Manuel; Fernández, Braulio J.; Vivas, L. and Sánchez Pérez, Gerardo Resumen En este trabajo presentamos la síntesis y caracterización del material ternario Ag2SnSe3dopado con Galio (Ga). Las muestras fueron sintetizadas por fusión directa de sus elementos en estequiometria 2:1:3 con dopaje de Ga de 100, 1000 y 10000 ppm. El análisis químico (EDX) permitió establecer las relaciones estequiométricas. El análisis térmico diferencial (DTA) indica la existencia de una fase principal alrededor de 503±C asociado al punto de fusión de los materiales y un pico alrededor de 101±C aún sin interpretación. El análisis de difracción de rayos-X indica que el material Ag2SnSe3cristaliza con fase principal en el sistema monoclínico con grupo espacial Cc, y parámetros de celda unidad: a = 7.18 A, b = 10.55 A, c = 6.70 A, β= 111.98ºC, y segundas fases, siendo identificada hasta el momento SnSe2. Abstract In this work we report the synthesis and characterization of the ternary material Ag2SnSe3 doped with Gallium (Ga). The samples were synthesized by direct melting of their elements in stoichimetric 2:1:3 doped with 100, 1000 and 10000 ppm of Ga. The chemical analysis (EDX) allowed us to establish the stoichiometric relationships. The differential thermal analysis (DTA) indicates the existence of a main phase around 503±C associated to the melting point of the materials and a peak around 101±C, still without interpretation. The X-ray diffraction analysis indicates that the material Ag2SnSe3 crystallizes with main phase in the monoclinic system with space group Cc, and unit cell parameters: a = 7.18 A, b = 10.55 A, c = 6.70 A, β= 111.98ºC, and second phases, being identified until the moment SnSe2. Artículo publicado en: Revista Mexicana de Física 53 (7) 262-264 mpireira@ula.ve mavu@ula.ve anita@ula.ve braulio@ula.ve Nivel monográfico

The aim of this study was to identify new compounds active against Plasmodium falciparum based on our previous research carried out on 3-phenylquinoxaline- 2-carbonitrile 1,4-di-N-oxide derivatives. Twelve compounds were synthesized and evaluated for antimalarial activity. Eight of them showed an IC50 < 1 μM against the 3D7 strain. Derivative 1 demonstrated high potency (IC50= 0.63 μM) and good selectivity (SI=10.35), thereby becoming a new lead-compound.

Chemical investigation of the methanol extract from the leaves of Arrabidaea patellifera, a Bignoniaceae from Panama, afforded mangiferin, isomangiferin, and six new derivatives (3'-O-p-hydroxybenzoylmangiferin, 3'-O-trans-coumaroylmangiferin, 6'-O-trans-coumaroylmangiferin, 3'-O-trans-cinnamoylmangiferin, 3'-O-trans-caffeoylmangiferin, and 3'- O-benzoylmangiferin). All these compounds had antioxidant and radical-scavenging activities, and four of them were relatively active in Vitro against Plasmodium falciparum. The structures were determined by spectrometric and chemical methods, including 1D and 2D NMR experiments and MS analysis.