19 research outputs found

    Phenolic composition and antioxidant activity in sparkling wines: Modulation by the ageing on lees

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    AbstractSparkling wines (SW) have a special biological ageing on lees that is performed using two distinct methods: in the bottle (Champenoise) or in isobaric tanks (Charmat method). The objective of this study was to compare the levels of phenolic compounds, β-Glucosidase and antioxidant activity during the ageing on lees, in samples of SW produced at industrial scale by both methods. The β-Glucosidase activity has been constant over time, showing a close relationship with all the polyphenols studied (resveratrol, piceid, tyrosol, gallic, caffeic and ferulic acids), which were affected by the sur lie time. With these cross-reactions, the biological properties of the SW were also modulated. The results showed that the long period of ageing decreased the antioxidant potential in all samples. This work demonstrates that the sur lie is more important than the production method itself, due to its ability to modulate the necessary changes to achieve the specific objective

    The impact of the American mink (Neovison vison) on native vertebrates in mountainous streams in Central Spain

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    The American mink (Neovison vison) is responsible for the widespread decline of its prey species in the regions where it is an invasive species. The current expansion of the mink in the Iberian Peninsula has aroused concern among conservationists about its negative impact on the rich native fauna. However, evidence for this is still scarce, although there are several studies establishing a direct causal relationship between declining native species and the presence of the American mink. Thus, it is important to further investigate the responses of native species to the American mink in several habitats and locations to enhance our knowledge about the patterns of the effect of the mink in Spain, as well as to inform conservation actions. A field study of the impact of the American mink on a mountainous vertebrate community in central Spain is presented. We studied six species: two fish, one amphibian, one bird, and two mammals. The general results showed a species-specific sensitivity to mink presence, with the Mediterranean water shrew (Neomys anomalus) and the southern water vole (Arvicola sapidus) being the most affected because their ranges were significantly decreased after the introduction of the mink. Regarding the other species, neither their abundance nor range was apparently affected by the American mink. The predatory behavior of the mink and interactions with other carnivores could account for these results. These data aid in shedding light about the current impact of the mink on invaded areas of the Iberian Peninsula and highlight the variability of its effects, as well as the urgent need to establish a general program of control of the mink to avoid negative effects upon native prey communities. Furthermore, given the different responses of native species, we propose that measures to protect native species should be based on species-specific goals and attributes. © 2013 Springer-Verlag Berlin Heidelberg.Pablo García-Díaz, Valentín Arévalo, Rafael Vicente, Miguel Lizan

    Optical wireless data transfer through biotissues:practical evidence and initial results

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    Abstract Light has been used in many medical applications to monitor health status and diagnose diseases. Examples include optical sensing through nearinfrared (NIR) spectroscopy, optical coherence tomography, and pulse oximetry. In this article, we propose and demonstrate digital communications through biological tissues using near-infrared light. There are many possible uses to an optical system transmitting information across tissues. In current practices, implants predominantly use radio frequency (RF) radiation for communication. However, molecular biology restricts use of the RF in terms of power, frequency etc., while interference and security issues represent technological challenges in RF communication. In this paper, we demonstrate a novel way of employing NIR light for wireless transmission of data through biological tissues. A phantom mimicking a biological tissue is illuminated with a NIR 810 nm wavelength light-emitting diode (LED), and a light detector with line-of-sight alignment is placed on receiving end. An experimental testbed for Optical Communications through Biotissue (OCBT) was designed and implemented using mostly off-the-shelf components. Measurements for different levels of optical output power and thicknesses were carried out. Transmission rates as high as several tens of kilobits-per-second across several millimeters of tissues were achieved. Hardware limitations in modulating the baseband signal prevented achieving higher data rates. In addition, a high-resolution picture was successfully transmitted through biotissue. The communication system as well as details of the testbed implementations are presented in this paper. Moreover, initial performance measures as well as suggestions for potential use of this optical communication system are also presented and discussed

    GPU accelerated real-time multi-functional spectral-domain optical coherence tomography system at 1300nm

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    We present a GPU accelerated multi-functional spectral domain optical coherence tomography system at 1300nm. The system is capable of real-time processing and display of every intensity image, comprised of 512 pixels by 2048 A-lines acquired at 20 frames per second. The update rate for all four images with size of 512 pixels by 2048 A-lines simultaneously (intensity, phase retardation, flow and en face view) is approximately 10 frames per second. Additionally, we report for the first time the characterization of phase retardation and diattenuation by a sample comprised of a stacked set of polarizing film and wave plate. The calculated optic axis orientation, phase retardation and diattenuation match well with expected values. The speed of each facet of the multi-functional OCT CPU-GPU hybrid acquisition system, intensity, phase retardation, and flow, were separately demonstrated by imaging a horseshoe crab lateral compound eye, a non-uniformly heated chicken muscle, and a microfluidic device. A mouse brain with thin skull preparation was imaged in vivo and demonstrated the capability of the system for live multi-functional OCT visualization
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