Papers by Gustavo Víctor Guinea
Ecf8 Torino 1990, Feb 6, 2013
Normas Para La Presentación De Los Trabajos Del XXII Encuentro Del Grupo Español De Fractura
This paper is a self-explained example of the format in which the original manuscripts should be ... more This paper is a self-explained example of the format in which the original manuscripts should be submitted to the XXII Encuentro del Grupo Español de Fractura which will take place in Almagro (Ciudad Real), March, 9-11, 2004. Please, write an abstract of about 150 words which accounts briefly and clearly for the objectives, contents and conclusions of the paper. It
Relationship Between Fibre Orientation and Tensile Strength of Natural Collagen Membranes for Heart Valve Leaflets
gef.es
... Decellularization is used for calcification prevention in porcine valve leaflets, and do not ... more ... Decellularization is used for calcification prevention in porcine valve leaflets, and do not induce changes in the mechanical properties [4]. Pericardium has as well to be decellularized to suppress ... 5. Mendoza-Novelo, B., et al., Decellularization of pericardial tissue and its ...
Normas Para La Presentación De Los Trabajos Del XXII Encuentro Del Grupo Español De Fractura
This paper is a self-explained example of the format in which the original manuscripts should be ... more This paper is a self-explained example of the format in which the original manuscripts should be submitted to the XXII Encuentro del Grupo Español de Fractura which will take place in Almagro (Ciudad Real), March, 9-11, 2004. Please, write an abstract of about 150 words which accounts briefly and clearly for the objectives, contents and conclusions of the paper. It
Absorci�n, Disipaci�n De Energ�a Mec�nica y Rotura De La Seda V�scida De Ara�a
Biomacromolecules, Jul 1, 2009
The development of an accurate and reproducible approach to measuring the tensile behavior of spi... more The development of an accurate and reproducible approach to measuring the tensile behavior of spider silk has allowed characterizing and comparing the range of mechanical properties exhibited by different spider species with unprecedented detail. The comparison of silks spun by spiders belonging to different phylogenetic groups has revealed that evolution locked in many of the important properties of spider silks very early in the history of orb-web weaving spiders, despite the fact that the silk gland system is relatively isolated in physiological terms from the rest of the organism and should thus mutate quickly. The variations observed between species may be grouped in at least two patterns that are shown not to be related to phylogeny. Beyond the relevance of these results for the evolutionary biology of spiders and silks, the conservation of the basic traits observed in the mechanical behavior of spider silks is likely to set a limit to the range of properties that can be expected from artificial fibers bioinspired in natural silks.
Ecf9 Varna 1992, Feb 8, 2013
Tensiones De Contracci�n Inducidas en Las Fibras De Seda De Ara�a Por Absorci�n De Agua
Macromolecules Issn 0024 9297 2011 02 Vol 44 N 5, Feb 3, 2011
The mechanical behavior and microstructure of bioinspired fibers spun from solutions of recombina... more The mechanical behavior and microstructure of bioinspired fibers spun from solutions of recombinant spidroin-like proteins were extensively characterized, and compared with those of natural spider silk fibers. It is confirmed that high performance bioinspired fibers indistinguishable from natural spider silk up to large strains can be produced through genetic engineering and conventional spinning technologies. It is also found that fibers spun from spidroin-like proteins that contain different motifs of sequence exhibit variations in their microstructure in terms of crystallinity and chain alignment, but these differences are not reflected in distinct tensile properties. This similarity in terms of their mechanical behavior indicates that bioinspired fibers are largely independent of their exact sequence of recombinant proteins and, in particular, of their proline content. Finally, it is shown that the largest differences between natural and bioinspired fibers are found at very large deformations, marking the ultimate challenge in the synthesis of silk-like fibers.
The effect of the boundary conditions on the cylinder splitting strength
An�lisis Mec�nico De Un Bypass Coronario T�rmino-Terminal
Mechanisms of Rupture in Splitting Tests
Aci Materials Journal, 1999
The fracture mechanisms in the splitting tensile test (Brazilian test) are studied experimentally... more The fracture mechanisms in the splitting tensile test (Brazilian test) are studied experimentally with special attention given to the influence of the width of the bearing strips. Tests of an extended size range (1:10) were conducted on mortar square prisms and granite discs. The tests were carried out on a closed-loop control system to obtain stable crack propagation. During the tests, crack initiation and propagation were recorded. The results confirm the existence of two fracture mechanisms in the splitting test: one associated with development of central cracks and the other with a secondary crack system on both sides of the bearing strips. These secondary cracks appear as a consequence of the stress redistribution induced by the central crack growth. The load-displacement curves recorded during the stable test show that two peak loads exist, one for each mechanism. The relative values of these peak loads depend on the specimen size and the width of the bearing strip: with a smaller size and a wider bearing strip, the relative value of the peak load associated with the secondary crack system increases.
Ecf9 Varna 1992, Feb 8, 2013
Macromolecules, Jun 25, 2007
Ecf11 Poitiers 1996, Feb 14, 2013
Stiffness associated with quasi-concentrated loads
Mater Struct, 1994
ABSTRACT
Journal of the Mechanical Behavior of Biomedical Materials, 2016
The aim of this study was to evaluate the variation of hardness with fatigue in calf pericardium,... more The aim of this study was to evaluate the variation of hardness with fatigue in calf pericardium, a biomaterial commonly used in bioprosthetic heart valves, and its relationship with the energy dissipated during the first fatigue cycle that has been shown to be a predictor of fatigue-life (García Páez et al., 2006, 2007; Rojo et al., 2010). Fatigue tests were performed in vitro on 24 pericardium specimens cut in a root-to-apex direction. The specimens were subjected to a maximum stress of 1 MPa in blocks of 10, 25, 50, 100, 250, 500, 1000 and 1500 cycles. By means of a modified Shore A hardness test procedure, the hardness of the specimen was measured before and after fatigue tests. Results showed a significant correlation of such hardness with fatigue performance and with the energy dissipated in the first cycle of fatigue, a predictor of pericardium durability. The study showed indentation hardness as a simple and reliable indicator of mechanical performance, one which could be easily implemented in improving tissue selection.
Scientific Reports, 2016
Spider major ampullate gland silks (MAS) vary greatly in material properties among species but, t... more Spider major ampullate gland silks (MAS) vary greatly in material properties among species but, this variation is shown here to be confined to evolutionary shifts along a single universal performance trajectory. This reveals an underlying design principle that is maintained across large changes in both spider ecology and silk chemistry. Persistence of this design principle becomes apparent after the material properties are defined relative to the true alignment parameter, which describes the orientation and stretching of the protein chains in the silk fiber. Our results show that the mechanical behavior of all Entelegynae major ampullate silk fibers, under any conditions, are described by this single parameter that connects the sequential action of three deformation micromechanisms during stretching: stressing of protein-protein hydrogen bonds, rotation of the β-nanocrystals and growth of the ordered fraction. Conservation of these traits for over 230 million years is an indication ...
Spider Silk as an Inspiration for Biomimicking
Advances in Science and Technology, Feb 10, 2009
Abstract Silks spun by arthropods exhibit a set of unique properties that have emerged as the res... more Abstract Silks spun by arthropods exhibit a set of unique properties that have emerged as the result of over four hundred million years of evolution. Silks show the most optimized combination of tensile strength and deformation at breaking, yielding the highest work of fracture of any known material. These outstanding features have thrust an increasing interest in reproducing or even improving the properties of natural silks. However, the advances in the field are hampered by an incomplete knowledge on the relation between ...
Brittle failure of dry spaghetti
Engineering Failure Analysis, 2004
ABSTRACT
Uploads
Papers by Gustavo Víctor Guinea