42 research outputs found

    Sudden drop of fractal dimension of electromagnetic emissions recorded prior to significant earthquake

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    The variation of fractal dimension and entropy during a damage evolution process, especially approaching critical failure, has been recently investigated. A sudden drop of fractal dimension has been proposed as a quantitative indicator of damage localization or a likely precursor of an impending catastrophic failure. In this contribution, electromagnetic emissions recorded prior to significant earthquake are analysed to investigate whether they also present such sudden fractal dimension and entropy drops as the main catastrophic event is approaching. The pre-earthquake electromagnetic time series analysis results reveal a good agreement to the theoretically expected ones indicating that the critical fracture is approaching

    Influence of amyloglucosidase in bread crust properties

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    Enzymes are used in baking as a useful tool for improving the processing behavior or properties of baked products. A number of enzymes have been proposed for improving specific volume, imparting softness, or extend the shelf life of breads, but scarce studies have been focused on bread crust. The aim of this study was to determine the use of amyloglucosidase for modulating the properties of the bread crust and increase its crispness. Increasing levels of enzyme were applied onto the surface of two different partially bake breads (thin and thick crust bread). Amyloglucosidase treatment affected significantly (P<0.05) the color of the crust and decreased the moisture content and water activity of the crusts. Mechanical properties were modified by amyloglucosidase, namely increasing levels of enzyme promoted a decrease in the force (Fm) required for crust rupture and an increase in the number of fracture events (Nwr) related to crispy products. Crust microstructure analysis confirmed that enzymatic treatment caused changes in the bread crust structure, leading to a disruption of the structure, by removing the starchy layer that covered the granules and increasing the number of voids, which agree with the texture fragility.Authors acknowledge the financial support of Spanish Ministry of Economy and Sustainability (Project AGL2011-23802), the European Regional Development Fund (FEDER), Generalitat Valenciana (Project Prometeo 2012/064) and the Consejo Superior de Investigaciones Cientificas (CSIC). R. Altamirano-Fortoul would like to thank her grant to CSIC. The authors also thank Forns Valencians S. A. (Spain) for supplying commercial frozen partially baked breads.Altamirano Fortoul, RDC.; Hernando Hernando, MI.; Molina Rosell, MC. (2014). Influence of amyloglucosidase in bread crust properties. Food and Bioprocess Technology. 7(4):1037-1046. https://doi.org/10.1007/s11947-013-1084-xS1037104674Altamirano-Fortoul R, Hernando I & Rosell CM (2013) Texture of bread crust: puncturing settings effect and its relationship to microstructure. Journal of Texture Studies. doi: 10.1111/j.1745-4603.2012.00368.x .Altamirano-Fortoul, R., Le Bail, A., Chevallier, S., & Rosell, C. M. (2012). Effect of the amount of steam during baking on bread crust features and water diffusion. Journal of Food Engineering, 108, 128–134.Altamirano-Fortoul R & Rosell CM (2010) Alternatives for extending crispiness of crusty breads. In Proceedings of International Conference on Food Innovation, FoodInnova, 25–29 October 2010, Valencia, Spain. ISBN978-84-693-5011-.9.Arimi, J. M., Duggan, E., O’sullivan, M., Lyng, J. G., & O’riordan, E. D. (2010). Effect of water activity on the crispiness of a biscuit (crackerbread): mechanical and acoustic evaluation. Food Research International, 43, 1650–1655.Castro-Prada, E. 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    Fracture strength and fractographic analysis of zirconia copings treated with four experimental silane primers

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    This study evaluated and compared the effect of new four experimental silane coupling agents on the fracture strength of zirconia copings. The findings were supported with fractographic and finite element analyses. All together 125 zirconia copings with a ?wall thickness of 0.6mm were fabricated on identical nickel-chromium master dies and then divided randomly into five groups (n=25). Four test groups were prepared according the experimental silane primer (labeled: OIWA1, OIWA2, OIWA3 and OIWA4) ?and one control group without silanization. The silane monomers used were: ?3-methacryloxypropyltrimethoxysilane (in OIWA1), ?3-acryloxypropyltrimethoxysilane (in OIWA2), ?3-?isocyanatopropyltriethoxysilane (in OIWA3) and styrylethyltrimethoxysilane (in OIWA4). Tribochemical sandblasting (silica-coating) treatment was performed to the inner surface of the copings in the ?test groups. All the specimens were silanized at the inner surfaces of the zirconia copings. Self-?adhesive universal resin cement was used to cement the copings to ?the underlying master die. Zirconia copings were vertically loaded on the ?cusp ?area until the first crack failure was occurred using Precision Universal Tester ?at a ?constant crosshead speed of 1mm/min. Then, the machine ?was manually controlled to cause more failure ?to further determine the texture of fracture. Three dimensional finite element analysis and fractography were performed to support the fracture strength findings. Based on the finite element analysis results, zirconia silanized with ?3-acryloyloxypropyltrimethoxysilane showed the highest fracture strength with a mean of ?963.75?N (SD 4.5N), while zirconia copings silanized with ?3-methacryloyloxypropyltrimethoxysilane showed a mean fracture strength value of ?925.65N (SD 2.4N). Styrylethyltrimethoxysilane-silanised zirconia showed mean fracture strength of 895.95N (SD 3.5N). Adding silane coupling agents to the resin-zirconia interface increased the fracture strengths significantly (ANOVA, p<0.05). Silanization with four new experimental silane primers in vitro produced significantly ?greater fracture strength than the control group not treated with the test silane.

    Distinguishing closely related amyloid precursors using an RNA aptamer

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    Although amyloid fibrils assembled in vitro commonly involve a single protein, fibrils formed in vivo can contain multiple protein sequences. The amyloidogenic protein human ?2-microglobulin (h?2m) can co-polymerize with its N-terminally truncated variant (?N6) in vitro to form hetero-polymeric fibrils that differ from their homo-polymeric counterparts. Discrimination between the different assembly precursors, for example by binding of a biomolecule to one species in a mixture of conformers, offers an opportunity to alter the course of co-assembly and the properties of the fibrils formed. Here, using h?2m and its amyloidogenic counterpart, ??6, we describe selection of a 2'F-modified RNA aptamer able to distinguish between these very similar proteins. SELEX with a N30 RNA pool yielded an aptamer (B6) that binds h?2m with an EC50 of ?200 nM. NMR spectroscopy was used to assign the (1)H-(15)N HSQC spectrum of the B6-h?2m complex, revealing that the aptamer binds to the face of h?2m containing the A, B, E, and D ?-strands. In contrast, binding of B6 to ?N6 is weak and less specific. Kinetic analysis of the effect of B6 on co-polymerization of h?2m and ?N6 revealed that the aptamer alters the kinetics of co-polymerization of the two proteins. The results reveal the potential of RNA aptamers as tools for elucidating the mechanisms of co-assembly in amyloid formation and as reagents able to discriminate between very similar protein conformers with different amyloid propensity

    Thin Film Growth Using Low-Energy Multi-Ion Beam Deposition System

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    ABSTRACTA high-current, low-energy multi-ion beam deposition system has been developed for the fabrication of tailored new materials. This system consists of two ion sources, a dual-sector type mass analyzer and a deceleration system. Several ion species can be extracted successively from the two ion sources by switching the mass analyzer selection. Artificially structured materials, especially having a layered structure, can be grown by the fine control of the growth process of each layer. Ar* ion deceleration characteristics of this ion beam deposition system and preliminary results about the epitaxial growth of Ca film on Si(100) are shown.</jats:p
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