Elastic biodegradable starch/ethylene-co-vinyl alcohol fibre-mesh scaffolds for tissue engineering applications

The fabrication of a biomaterial scaffold, with adequate physical and structural properties for tissue engineering applications, is reported. A blend of starch with ethylene-vinyl alcohol (50/50 w/w, SEVA-C) is used to produce 3D fibre-mesh scaffolds by wet-spinning. The scaffolds are characterized in terms of morphology, porosity, interconnectivity, and pore size, using scanning electron microscopy (SEM) and microcomputed tomography (μCT). The degradation behavior, as well as the mechanical properties of the scaffolds, is investigated in presence of alpha-amylase enzyme at physiological concentration. Scaffolds with porosities ranging from 43 to 52%, interconnectivity of ∼70.5% and pore size between 118 and 159 μm, can be fabricated using the proposed methodology. The scaffolds exhibit an elastic behavior in the wet state with a compressive modulus of 7.96±0.32 MPa. Degradation studies show that SEVA-C scaffolds are susceptible to enzymatic degradation by alpha-amylase, confirmed by the increase of weight loss (40% of weight loss after 12 weeks) and presence of degradation products (reducing sugars) in solution. The diameter of SEVA-C scaffolds decreases with degradation time, increasing the overall porosity, interconnectivity and pore size. In vitro cell studies with human osteosarcoma cell line (SaOs-2) showed a nontoxic and cytocompatible behavior of the developed fibre mesh scaffolds. The positive cellular response, together with structural and degradable properties, suggests that 3D SEVA-C fibre-meshes may be good candidates as tissue engineering scaffolds. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40504. Copyright © 2014 Wiley Periodicals, Inc.This work was supported by national funds through the Portuguese Foundation for Science and Technology under the scope of the project PTDC/CTM/67560/2006 and by the European Regional Development Fund (ERDF) through the Operational Competitiveness Programme “COMPETE” (FCOMP-01-0124-FEDER-007148)

Preliminary catalog of pictures taken on the lunar surface during the Apollo 15 mission

Catalog of all pictures taken from lunar module or lunar surface during Apollo 15 missio

Newton i les seves contribucions al concepte contemporani de ciència

Postprint (published version

A Low Energy FPGA Platform for Real-Time Event-Based Control

We present a wireless sensor node suitable for event-based real-time control networks. The node achieves low-power operation thanks to tight clock synchronisation with the network master (at present we refer to a star network but extensions are envisaged). Also, the node does not employ any programmable device but rather an FPGA, thus being inherently immune to attacks based on code tampering. Experimental results on a simple laboratory apparatus are presented

Weighted power counting and chiral dimensional regularization

We define a modified dimensional-regularization technique that overcomes several difficulties of the ordinary technique, and is specially designed to work efficiently in chiral and parity violating quantum field theories, in arbitrary dimensions greater than 2. When the dimension of spacetime is continued to complex values, spinors, vectors and tensors keep the components they have in the physical dimension, therefore the $\gamma$ matrices are the standard ones. Propagators are regularized with the help of evanescent higher-derivative kinetic terms, which are of the Majorana type in the case of chiral fermions. If the new terms are organized in a clever way, weighted power counting provides an efficient control on the renormalization of the theory, and allows us to show that the resulting chiral dimensional regularization is consistent to all orders. The new technique considerably simplifies the proofs of properties that hold to all orders, and makes them suitable to be generalized to wider classes of models. Typical examples are the renormalizability of chiral gauge theories and the Adler-Bardeen theorem. The difficulty of explicit computations, on the other hand, may increase.Comment: 41 pages; v2: minor changes, PRD versio

El aprendizaje de audacity para la edición y producción de contenidos didácticos digitales

En la sociedad actual resulta indispensable proporcionar una capacitación adecuada a los futuros docentes para que puedan desarrollar metodologías innovadoras, donde las TIC y los recursos didácticos digitales desempeñan un papel clave y permiten que los conocimientos y habilidades del alumno tengan un desarrollo exitoso. Esta investigación se aborda desde una metodología cuantitativa, mediante el uso de un cuestionario creado ad hoc sobre aprendizaje y la evaluación de la herramienta Audacity para la creación de recursos didácticos digitales en el Grado de Educación Infantil de la Universidad de Córdoba. Los resultados muestran una valoración positiva de la experiencia vivida, así como de la herramienta estudiada.In present society it is essential to provide the necessary training to future teachers so they can accomplish innovative teaching and learning methodologies, where ICT and digital learning resources play a key role that will enable the student’s knowledge and skills to be successfully developed. This research is approached from a quantitative methodology, by using a questionnaire created ad hoc about the learning and the assessment of the Audacity software tool for creating digital didactic resources, in the Early Childhood Education Degree from the University of Cordoba. The results obtained show a positive assessment of the tool studied and its subsequent use for audiovisual productions

Incorporated citizens: multinational high-tech companies and the BoP

In this article, I examine HP’s e-Inclusion program and its implementation in India to show how the high-tech industry’s efforts to alleviate poverty profitably are guided by C. K. Prahalad’s ideas about the Bottom of the Pyramid (BoP), and are framed as digital corporate citizenship activities. While the BoP highlights the importance of new markets for high-tech companies, the discourse of digital corporate citizenship creates an enabling environment in which transnational high-tech companies can gain political access to new consumers at the BoP. The resulting digital corporate citizenship/BoP nexus leads to the extension of governments’ bureaucratic reach and the formation of electronic entrepreneurs

Contribució a la brioflora d’Andorra

Es donen a conèixer 33 taxons de molses nous per Andorra així com d’altres interessants per la seva raresa en aquest territori o als Pirineus en general. Destaquem per les escasses citacions als Pirineus: Dicranodontium uncinatum, Hylocomiastrum pyrenaicum, H. umbratum, Encalypta rhaptocarpa, Grimmia alpestris, G. atrata, G. funalis i Sphagnum warnstorfii.33 taxa of mosses new for Andorra are reported, including comments on other interesting species rare in this country or in the rest of the Pyrenees. Dicranodontium uncinatum, Hylocomiastrum pyrenaicum, H. umbratum, Encalypta rhaptocarpa, Grimmia alpestris, G. atrata, G. funalis and Sphagnum warnstorfii, considered rare in the Pyrenees, are pointed out