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Jang B.,ETH Zurich | Pellicer E.,Facultat de Ciencies | Guerrero M.,Facultat de Ciencies | Chen X.,ETH Zurich | And 4 more authors.
ACS Applied Materials and Interfaces | Year: 2014

Electrodeposition is a versatile method, which enables the fabrication of a variety of wire-like nanoarchitectures such as nanowires, nanorods, and nanotubes. By means of template-assisted electrodeposition, segmented Au/Co/Au nanowires are grown in anodic aluminum oxide templates from two different electrolytes. To tailor the properties of the cobalt segments, several electrochemical conditions are studied as a function of current density, pulse deposition, and pH. The morphology, crystal structure, and magnetic properties are accordingly investigated. Changes in the deposition conditions affect the cobalt electrocrystallization process directly. Cobalt tends to crystallize mainly in the hexagonal close-packed structure, which is the reason cobalt might not accommodate satisfactorily on the face-centered cubic Au surface or vice versa. We demonstrate that by modifying the electrolyte and the applied current densities, changes in the texture and the crystalline structure of cobalt lead to a good quality connection between dissimilar segments. In particular, lowering the bath pH, or using pulse plating at a high overpotential, produces polycrystalline fcc Co and thus well-connected Co/Au bimetallic junctions with smooth interface. These are crucial factors to be carefully considered taking into account that nanowires are potential building blocks in micro- and nanoelectromechanical systems. © 2014 American Chemical Society.


Alonso A.,Autonomous University of Barcelona | Vigues N.,Facultat de Ciencies | Rodriguez-Rodriguez R.,International University of Catalonia | Borrise X.,CSIC - National Center of Microelectronics | And 4 more authors.
Nanotechnology | Year: 2016

This paper presents the study of the dynamics of the formation of polymer-assisted highly-orientated polycrystalline cubic structures (CS) by a fractal-mediated mechanism. This mechanism involves the formation of seed Ag@Co nanoparticles by InterMatrix Synthesis and subsequent overgrowth after incubation at a low temperature in chloride and phosphate solutions. These ions promote the dissolution and recrystallization in an ordered configuration of pre-synthetized nanoparticles initially embedded in negatively-charged polymeric matrices. During recrystallization, silver ions aggregate in AgCl@Co fractal-like structures, then evolve into regular polycrystalline solid nanostructures (e.g. CS) in a single crystallization step on specific regions of the ion exchange resin (IER) which maintain the integrity of polycrystalline nanocubes. Here, we study the essential role of the IER in the formation of these CS for the maintenance of their integrity and stability. Thus, this synthesis protocol may be easily expanded to the composition of other nanoparticles providing an interesting, cheap and simple alternative for cubic structure formation and isolation. © 2016 IOP Publishing Ltd.


Aliende C.,University of Burgos | Perez-Manrique M.,University of Burgos | Jalon F.A.,University of Castilla - La Mancha | Manzano B.R.,University of Castilla - La Mancha | And 8 more authors.
Journal of Inorganic Biochemistry | Year: 2012

Aminophosphines 2-(diphenylphosphino)-1-methylimidazole (dpim) and diphenyl-2-pyridylphosphine (PPh2py) have been used to prepare two series of Ru(II) arene complexes of formulae [(η6-p-cymene) Ru(κ2-O,O′-X)(κ1-P-dpim)]Y (series a: 1a·Y-3a·Y) and [(η6-p-cymene) Ru(κ2-O,O′-X)(κ1-P-PPh2py)]Y (series b: 1b·Y-3b·Y) (where X = acac, acetylacetonate; bzac, benzoyl acetonate; dbzm, dibenzoyl methanoate; Y = BF4, BPh 4). The structures of 1a·BF4, 1a·BPh 4, 3a·BF4, 1b·BPh4 and 3b·BPh4 were determined by X-ray diffraction. The tetrafluoroborate derivatives are more soluble in organic solvents than their tetraphenylborate counterparts. Five BF4 - derivatives (all except the unstable 1b·BF4) were selected to evaluate the cytotoxic behavior in vitro against the human cancer cell lines MCF-7 (breast cancer) and CAPAN-1 (pancreatic cancer). 2b·BF4 and 3b·BF4 exhibited IC50 values similar to those of cisplatin. Electrophoresis and AFM studies showed good correspondence between the biological activity levels of 2b·BF4 and 3b·BF 4 and their ability to modify the DNA structure. Hydrolytic studies indicate that aquation could be involved in the activation mechanism of these complexes and confirm that the hydrolysis rate of 3b·BF4 is higher than that of 3a·BF4. Thus, the cytotoxic activity trends are explained in terms of the higher reactivity of derivatives from series b, which in turn is rationalized as being the result of the electronic features of dpim and PPh2py established by cyclic voltammetry measurements. © 2012 Elsevier Inc. All rights reserved.


Ferraz M.A.M.M.,University Utrecht | Morato R.,Facultat de Ciencies | Yeste M.,Autonomous University of Barcelona | Arcarons N.,Autonomous University of Barcelona | And 5 more authors.
Theriogenology | Year: 2014

The present study examined the relationship between the relative amount of high motile sperm and sperm-oocyte interactions obtained from Holstein bull ejaculates. Post-thaw sperm motility was analyzed using a computer-assisted sperm analyzer system and evaluated to determine the sperm motility subpopulations. Adhesion and penetration of zona pellucida (ZP) and pronucleus formation using post-thawed samples (15 ejaculates form 5 different bulls) with different percentages of sperm in the subpopulation with the fastest and most progressive subpopulation (subpopulation 4 [SP4]) were analyzed. The correlation between the proportion of sperm in SP4 and the number of spermatozoa bound to the zona pellucida (ZBA), the penetration rate, and the rate of pronucleus formation were calculated. A significant (P < 0.05) and positive correlation was found between the number of spermatozoa bound to the zona pellucida, the penetration rate, and the rate of pronucleus formation with the proportion of sperm in SP4 (r = 0.79, r = 0.66, and r = 0.63, respectively). Our results suggest that this specific high motile and progressive subpopulation is positively and significantly correlated with the ability of a thawed bull semen sample to interact properly with the oocyte and its extracellular vestments. These findings emphasize the relevance of analyzing semen subpopulation composition to predict bull sperm fertilizing ability and to select Holstein bulls for breeding purposes. © 2014 Elsevier Inc.


PubMed | Area de Seleccion y Reproduccion Animal, University Utrecht, Facultat de Ciencies, University of Santiago de Compostela and Autonomous University of Barcelona
Type: Journal Article | Journal: Theriogenology | Year: 2014

The present study examined the relationship between the relative amount of high motile sperm and sperm-oocyte interactions obtained from Holstein bull ejaculates. Post-thaw sperm motility was analyzed using a computer-assisted sperm analyzer system and evaluated to determine the sperm motility subpopulations. Adhesion and penetration of zona pellucida (ZP) and pronucleus formation using post-thawed samples (15 ejaculates form 5 different bulls) with different percentages of sperm in the subpopulation with the fastest and most progressive subpopulation (subpopulation 4 [SP4]) were analyzed. The correlation between the proportion of sperm in SP4 and the number of spermatozoa bound to the zona pellucida (ZBA), the penetration rate, and the rate of pronucleus formation were calculated. A significant (P < 0.05) and positive correlation was found between the number of spermatozoa bound to the zona pellucida, the penetration rate, and the rate of pronucleus formation with the proportion of sperm in SP4 (r = 0.79, r = 0.66, and r = 0.63, respectively). Our results suggest that this specific high motile and progressive subpopulation is positively and significantly correlated with the ability of a thawed bull semen sample to interact properly with the oocyte and its extracellular vestments. These findings emphasize the relevance of analyzing semen subpopulation composition to predict bull sperm fertilizing ability and to select Holstein bulls for breeding purposes.


Fraga H.,Facultat de Ciencies | Ventura S.,Facultat de Ciencies | Ventura S.,Autonomous University of Barcelona
Current Protein and Peptide Science | Year: 2012

The process of oxidative folding in the intermembrane mitochondrial space (IMS) is an exciting field of research because folding is simultaneously coupled to protein translocation and functional regulation. Contrary to the endoplasmatic reticulum ER where several chaperones of the disulfide isomerase family exist, oxidative folding in the IMS is exclusively catalyzed by the oxoreductase Mia40 that recognizes a group of proteins with characteristic cysteine motifs organized in twin CX 3C, twin CX 9C or CX 2C motifs. In this review, we discuss the structural and biochemical studies leading to our current understanding of the Mia40 pathway as well as the open questions on the field. In fact, despite significant advances, several key points on the Mia40 pathway remain to clarify namely on the molecular mechanism trough which substrate oxidative folding is catalyzed. This issue is receiving increasing attention since failures in the import, sorting and folding of mitochondrial proteins is related to an increasing number of debilitating human disorders. © 2012 Bentham Science Publishers.


Cognola G.,University of Trento | Elizalde E.,Facultat de Ciencies | Zerbini S.,University of Trento
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

By making use of the background field method, the one-loop quantization for Euclidean Einstein-Weyl quadratic gravity model on the de Sitter universe is investigated. Using generalized zeta function regularization, the on-shell and off-shell one-loop effective actions are explicitly obtained, and one-loop renormalizability, as well as the corresponding one-loop renormalization group equations, is discussed. The so-called critical gravity is also considered. © 2013 American Physical Society.


Lopez-Revelles A.J.,Facultat de Ciencies
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

Two different realistic F(R) modified gravity models are considered in the framework of the Friedmann-Lemetre-Robertson-Walker universe. The parameters of these two models are adjusted to reach coherence with the most recent and accurate observations of the current Universe. A study of the growth of matter density perturbations is done, and several parametrizations of the growth index are developed for both models. The ansatz for the growth index given by γ=γ0+γ1z/(1+z) seems to be the best parametrization for the two models considered. Finally, the values obtained for γ0 and γ1 can be used in order to characterize these two models and to differentiate them from others such as the Hu-Sawicki model. © 2013 American Physical Society.


Miravete V.,Facultat de Ciencies | Roura-Pascual N.,Facultat de Ciencies | Roura-Pascual N.,Center Tecnologic Forestal Of Catalonia | Dunn R.R.,North Carolina State University | Gomez C.,Facultat de Ciencies
Biology Letters | Year: 2013

Human transportation facilitates the dispersal of exotic ants, but few studies have quantified the magnitude and geography of these movements. We used several non-parametric indexes to estimate the number of species successfully introduced to or established in newregions.We also compared their source biogeographic realms to assess the importance of the geographical origin in determining the likelihood of establishment after introduction. Data on exotic ants derive from studies of three temperate regions. Our results suggest that the numbers of introduced or established ants may be much larger than the numbers so far documented. Ants introduced or established in new regions tend to arrive from the same or neighbouring realms, as would be expected if exotic species tend to match climates and if arrival/establishment is dependent upon higher trade rates from neighbouring countries. © 2013 The Author(s) Published by the Royal Society. All rights reserved.

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