Doñana. Acta vertebrata. vol 22 (1/2)

Relación entre el uso del espacio del mito (Aeghitalos caudatus) y la disponibilidad de artrópodos durante el periodo primavera-veranoHábitos frugívoros de la corzuela parda (Mazama gouazoubira, Ficher, 1814) (Mammalia: Cervidae), en un ambiente secundario de yungasComparación entre varias técnicas de estimación de la edad en zorros, Vulpes vulpes, de Doñana (sur de la Península Ibérica)Características morfológicas de los corzos (Capreolus capreolus) de las sierras de Cádiz-Málaga.Etograma y relación de la conducta con el hábitat y con la edad en el ñandú (Rhea americana)Variación estacional del área de campeo de Oxymycterus rufus (Rodentia: Cricetidae), en el delta del rio Paraná, ArgentinaTracking of a female american mink (Mustela vison, Schreber, 1777) in NE Spain.Nidificación de láridos en la provincia de Almeria (SE Ibérico)Expansión del área de distribución de Microtus arvalis asturianus Miller, 1908 (Rodentia, Arvicolidae) en la meseta norte (España)Diet of the thekla lark, Galerida theklae, in a shrubsteppe of southeastern SpainAlimentación de la lechuza campestre (Asio flammeus) en la submeseta norte (España), durante el periodo reproductorUso de cajas anidaderas por lirones grises (Glis glis) y ratones leonados (Apodemus flavicollis) en el norte de la Península Ibérica.Theoretical flight ranges of waders resting in the Ebro Delta during autumn migrationPeer reviewe

Controlled Growth of CdS Quantum Dots

The role of 3-mercaptopropionic acid as a surface anchoring group and the reaction temperature for the controlled growth of CdS crystals was investigated from a one-step aqueous synthesis carried out both at room temperature and using a hydrothermal route. The thiol group of 3-mercaptopropionic acid forms a relatively strong bond with the cadmium atoms found at the particle surface reducing the crystal growth rate. This leads to the formation of monodisperse crystals of about 2 nm diameter. For a low thermal activation, at room temperature, for instance, the crystal growth is mainly determined by the nucleation process without evidence of a large contribution from Ostwald ripening. When the thermal activation competes with the binding energy for the thiol group to the cadmium atom, the surface shell becomes unstable and the crystals growth involves the coarsening mechanism. Under hydrothermal conditions the radius (r ) for the obtained crystals follows a linear dependence for r 3 versus t (reaction time). The crystal growing process is halted when the colloidal suspension is cooled. An appropriate control for the time and temperature of heating allows crystals of a tailored size to be obtained. The obtained colloidal suspensions of CdS nanocrystals were characterized from optical absorption, high-resolution transmission electron microscopy, and photoluminescence data

Síntesis y caracterización de nanopartículas magnéticas basadas en la MnFe2O4 tipo espinela

Se describe un método de síntesis por microemulsión en micelas inversas en el sistema agua/tolueno usando dodecilbencenosulfonato de sodio (NaDBS) como surfactante para sintetizar nanopartículas (NPs) superparamagnéticas (SPM) de ferrita de manganeso (MnFe2O4). Se introdujo una variación al método de síntesis reportado en la literatura, siendo esta realizar un tratamiento térmico a reflujo antes del tratamiento en atmósfera inerte. Esto permitió obtener un material con una cristalinidad adecuada y un comportamiento SPM. Se caracterizó el producto obtenido por difracción de rayos X (DRX), microscopía electrónica de transmisión (TEM) y magnetometría vibracional. El patrón de DRX de polvo reveló la formación de la fase MnFe2O4, tipo espinela, de grupo espacial Fd3m, acompañada de la fase secundaria hematita ( -Fe2O3) de grupo espacial R-3c. El tamaño de las nanopartículas fue estimado a partir del ajuste del perfil del patrón de polvos, obteniéndose tamaños promedios que variaron entre 5 y 25 nm en dependencia del tratamiento térmico a que fueron sometidas. La magnetometría vibracional mostró que las NPs de MnFe2O4 de menor tamaño, preparadas siguiendo esta ruta de síntesis presentaron un comportamiento SPM a temperatura ambiente. Se estimó además el grosor de la capa magnéticamente inactiva, de alrededor de 0,9 nm, responsable de la disminución de los valores de magnetización de saturación ( S) al disminuir el tamaño de partícula

Gold nanoparticles conjugated to benzoylmercaptoacetyltriglycine and L-cysteine methylester

Benzoyl-protected mercaptoacetyltriglycine, a synthetic precursor used in the preparation of Technetium- 99 m-mercaptoacetyltriglycine, a radiopharmaceutical for renal tubular function and L-cysteine methylester, a small, non-zwitterionic amino acid derivative, were used as capping agents of gold nanoparticles obtained by borohydride reduction method. The capped gold nanoparticles composites were prepared from aqueous solutions and characterized by UV–Vis, infrared and Raman spectra and Transmission Electron Microscopy images. The presence of the ligands and its different binding mode to the particles as a consequence of the benzoyl-protection of the thiol group in benzoyl-protected mercaptoacetyltriglycine were evidenced from infrared and Raman spectra. The stability on aging in water solution of the formed composites is discussed from the obtained UV–Vis spectra. 2010 Elsevier Inc. All rights reserve

Síntesis de nanopartículas de CdS por vía hidrotermal

En este trabajo se reportan las propiedades derivadas de la caracterización de nanopartículas [NPs] de CdS estabilizadas con Acido 3-Mercaptopropinico [AMP], por síntesis vía hidrotermal a una temperatura de 180°C, variando el tiempo de reacción, entre 20 a 160 minutos. En estas condiciones de reacción, se observa una fina distribución de tamaños, según indica el pico excitónico del espectro de UV-Vis. Al regular la temperatura de reacción se puede tener un control sobre el tamaño promedio de más NPs sintetizadas

Sorption of Gold by Naked and Thiol-Capped Magnetite Nanoparticles: An XPS Approach

Iron oxide nanoparticles are promising materials for many technological and environmental applications due to their versatile functionalization and magnetic properties that allow a facile remote control, separation and analyte recovery. In this contribution, the results of gold­(III) sorption by naked and DMSA-capped (DMSA = m-2,3,dimercapto succinic acid) magnetite nanoparticles are discussed. Magnetite nanoparticles of 8 nm diameter were first synthesized by thermal decomposition of iron­(III) oleate followed by a ligand exchange reaction to substitute oleic acid (OA) molecules by DMSA. Such systems of coated magnetite nanoparticles were characterized with Fourier transform infrared (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and magnetic measurements. FT-IR spectroscopy suggests that in Fe₃O₄@DMSA the organic coating is not homogeneous and it interacts with surface iron cations either through the carboxylate groups (by forming bridging bidentate complexes) or through disulfide bonds after oxidation of thiol groups. The magnetic measurements show that the nanoparticles are in the superparamagnetic range at room temperature despite the presence of dipolar interactions. The gold­(III) adsorption isotherms for both bare Fe₃O₄ and Fe₃O₄@DMSA nanoparticles were fitted with the Langmuir and Freundlich models. The better fit for the second model suggests the heterogeneous nature of the surface and the multilayer nature of gold adsorption. XPS spectra reveal that the adsorption of Au­(III) ions comprises mostly its reduction to Au⁰ by disulfide groups, although there is a fraction of these gold ions that is reduced directly onto the bare surface of the iron oxide leading to Fe­(II) oxidation. According to the recorded optical absorption spectra, gold clusters of metallic character are also formed at the nanoparticle surface, a fraction of them forming subnanometer aggregates. The magnetic recovery of gold by this nanosystem could be extendable to other heavy metals

Serial Endothelial Cell Count of Donor Corneal Buttons in Optisol-GS

AbstractOptisol–GS storage medium allows donor corneas to remain viable until they are transplanted to cornea-blind recipients. In order to remain viable, the corneal endothelial cell density (ECD) must remain above 2 200 cells per mm2. The objective of this study is to determine how long donor corneas may remain viable in Optisol-GS based on their ECD. Although our findings show that the ECD of corneas stored in Optisol-GS decreased steadily, it remained above the critical level of 2 200 cells per mm2 for up to 9 days, suggesting that corneal buttons may remain viable for at least this amount of time

The effect of methylphenidate and rearing environment on behavioral inhibition in adult male rats

The effect of the type of CNT (functionalized and non-functionalized) on the dielectric relaxation phenomena and conductivity of MWCNT/chitosan (MWCNT/CS) was investigated. Composites were prepared by the solvent cast method by homogeneously dispersing CNT into a CS matrix. FTIR analysis suggests the formation of hydrogen bonding in functionalized-MWCNT/CS whereas the CS remains unaffected in non-functionalized films. In the low conductivity region, the ?-relaxation process associated with a glass transition in CS is affected by the MWCNT; the Vogel temperature increases due to a decrease of the water content. The ?-relaxation exhibits a typical Arrhenius-type temperature dependence that is independent on the moisture content. Strong interfacial interactions of functionalized-MWCNT with the CS matrix are responsible for high values of the contact resistance Rc between individual CNT. Conversely, non-functionalized MWCNTs exhibit a typical 3D percolation threshold at ca. 4 wt %. " 2015 Elsevier B.V. All rights reserved.",,,,,,"10.1016/j.matchemphys.2015.02.041",,,"http://hdl.handle.net/20.500.12104/45086","http://www.scopus.com/inward/record.url?eid=2-s2.0-84924626391&partnerID=40&md5=2077a8248f1178527deca8ec39ee5bde",,,,,,,,"Materials Chemistry and Physics",,"25

Dispositivos biocompatibles para La liberación de Dopamina en ratas

Instituto Politécnico Nacional, CICATA-Legari