3,787 research outputs found

    Smart grid architecture for rural distribution networks: application to a Spanish pilot network

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    This paper presents a novel architecture for rural distribution grids. This architecture is designed to modernize traditional rural networks into new Smart Grid ones. The architecture tackles innovation actions on both the power plane and the management plane of the system. In the power plane, the architecture focuses on exploiting the synergies between telecommunications and innovative technologies based on power electronics managing low scale electrical storage. In the management plane, a decentralized management system is proposed based on the addition of two new agents assisting the typical Supervisory Control And Data Acquisition (SCADA) system of distribution system operators. Altogether, the proposed architecture enables operators to use more effectively—in an automated and decentralized way—weak rural distribution systems, increasing the capability to integrate new distributed energy resources. This architecture is being implemented in a real Pilot Network located in Spain, in the frame of the European Smart Rural Grid project. The paper also includes a study case showing one of the potentialities of one of the principal technologies developed in the project and underpinning the realization of the new architecture: the so-called Intelligent Distribution Power Router.Postprint (published version

    Cardioprotective Effects of S-Nitrosothiols in Ischemia- Reperfusion: Role for Mitochondria and Calcium Channels

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    The most important clinical consequence of coronary disease is acute myocardial infarction caused by an occlusion that limits the irrigation to the heart. Although the gold standard treatment is to restore blood flow, this reperfusion causes inherent damage by increasing the size of the infarcted area primarily through the opening of the mitochondrial permeability transition pore (MPTP). The cardioprotective effect of nitric oxide (NO) has been described to operate through S-nitrosylation of several important proteins in the cardiomyocytes such as the calcium channels RyR2 and the L-type Ca2+ channel and mitochondrial proteins, including the MPTP. In this sense, an attractive strategy to prevent the ischemia-reperfusion damage is to increase the bioavailability of endogenous S-nitrosothiols. S-nitrosoglutathione reductase (GSNOR) is an enzyme involved in the metabolism of NO through denitrosylation, which would limit the cardioprotective effect of NO. Although inhibition of GSNOR has been studied in different organs, its effects on myocardial reperfusion have not yet been fully elucidated. In this chapter, we review the pathophysiology underlying myocardial reperfusion injury and the opening of the MPTP along with the cardioprotective role of S-nitrosothiols and the potential role for GSNOR

    Nitroso-Redox Crosstalk in Diabetic Cardiomyopathy

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    Diabetes mellitus is one of the most common chronic diseases worldwide. Diabetic cardiomyopathy (DM) is the deterioration of the myocardial function and morphology produced by the altered glucose metabolism imposed in diabetes. This process of cardiac deterioration involves the generation of oxidative species. In the diabetic heart, several sources contribute to the observed oxidative stress, such as xanthine oxidoreductase (XOR), nicotinamide adenine dinucleotide phosphate (NADPH), nitrogen oxidases (NOX), mitochondria, and uncoupled nitric oxide synthases (NOS). A direct consequence of the increased production of reactive oxygen species (ROS) is NOS uncoupling. This is the aftermath of the oxidation of tetrahydrobioterin (BH4), an essential cofactor for NOS activity. When NOS is uncoupled, its activity is redirected toward the production of superoxide, instead of nitric oxide (NO), further contributing to the oxidative process. This nitroso-redox disarrangement has a direct impact on the excitation-contraction-coupling machinery of the myocyte, in the mitochondrial stability impairing energy production and favoring apoptosis, myocardial fibrosis, ultimately reducing cardiac function. This review focuses on the impact of superoxide sources in the diabetic heart and the pharmacological approaches that are currently under investigation as possible therapeutic tools

    Gene Loss and Horizontal Gene Transfer Contributed to the Genome Evolution of the Extreme Acidophile “Ferrovum”

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    IndexaciĂłn: Web of Science. Scopus.Acid mine drainage (AMD), associated with active and abandoned mining sites, is a habitat for acidophilic microorganisms that gain energy from the oxidation of reduced sulfur compounds and ferrous iron and that thrive at pH below 4. Members of the recently proposed genus "Ferrovurn" are the first acidophilic iron oxidizers to be described within the Betaproteobacteria. Although they have been detected as typical community members in AMD habitats worldwide, knowledge of their phylogenetic and metabolic diversity is scarce. Genomics approaches appear to be most promising in addressing this lacuna since isolation and cultivation of "Ferrovurn" has proven to be extremely difficult and has so far only been successful for the designated type strain-Ferrovum myxofaciens" P3G. In this study, the genomes of two novel strains of "Ferrovurn" (PN-J185 and Z-31) derived from water samples of a mine water treatment plant were sequenced. These genomes were compared with those of "Ferrovum" sp. JA12 that also originated from the mine water treatment plant, and of the type strain (P3G). Phylogenomic scrutiny suggests that the four strains represent three "Ferrovum" species that cluster in two groups (1 and 2). Comprehensive analysis of their predicted metabolic pathways revealed that these groups harbor characteristic metabolic profiles, notably with respect to motility, chemotaxis, nitrogen metabolism, biofilm formation and their potential strategies to cope with the acidic environment. For example, while the "F myxofaciens" strains (group 1) appear to be motile and diazotrophic, the non-motile group 2 strains have the predicted potential to use a greater variety of fixed nitrogen sources. Furthermore, analysis of their genome synteny provides first insights into their genome evolution, suggesting that horizontal gene transfer and genome reduction in the group 2 strains by loss of genes encoding complete metabolic pathways or physiological features contributed to the observed diversification.http://journal.frontiersin.org/article/10.3389/fmicb.2016.00797/ful

    Distribution and Conservation Status of Antillean Manatees (Trichechus manatus manatus) in Honduras

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    The Antillean manatee, Trichechus manatus manatus, is among the most threatened mammals in Honduras, yet the last published study is from 1980. Since then, the North Coast of Honduras has experienced rapid population growth and land cover change possibly causing habitat loss for manatees. We conducted aerial, boat, and interview surveys between 2005-2007 along the northern and remote eastern coasts of Honduras to assess the current status and distribution of manatees. In addition, we compiled all available data on manatee mortality from museum specimens, unpublished reports, and interviews to determine current threats. We averaged 1.2 manatee sightings per survey hour during six flights along the North Coast in March-April 2006 during 14.4 aerial survey hours. Sightings were mainly clustered in Cuero y Salado Wildlife Refuge (CSWR) and Rios Chapagua and Aguan, which we indentify as important conservation areas. Our total and average sightings per survey hour in CSWR were much lower than those reported in 1979-80, in spite of the area being protected since 1987. Our interviews indicate that manatees are still present on the eastern coast (La Mosquitia), however we observed none during 14.5 survey hours in June 2005 and April 2007. The major cause of known mortality from 1970-2007, based on 26 records, was due to entanglement in fishnets. Despite local and federal protection, manatees are still poached and opportunistically caught in fishnets. While some efforts have been made by local NGOs to raise public awareness for manatees, a national conservation program is highly recommended to centralize and coordinate efforts

    Bismuth incorporation and the role of ordering in GaAsBi/GaAs structures

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    The structure and composition of single GaAsBi/GaAs epilayers grown by molecular beam epitaxy were investigated by optical and transmission electron microscopy techniques. Firstly, the GaAsBi layers exhibit two distinct regions and a varying Bi composition profile in the growth direction. In the lower (25 nm) region, the Bi content decays exponentially from an initial maximum value, while the upper region comprises an almost constant Bi content until the end of the layer. Secondly, despite the relatively low Bi content, CuPtB-type ordering was observed both in electron diffraction patterns and in fast Fourier transform reconstructions from high-resolution transmission electron microscopy images. The estimation of the long-range ordering parameter and the development of ordering maps by using geometrical phase algorithms indicate a direct connection between the solubility of Bi and the amount of ordering. The occurrence of both phase separation and atomic ordering has a significant effect on the optical properties of these layers

    KIC InnoEnergy Project Neptune: development of a floating LiDAR buoy for wind, wave and current measurements

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    The KIC-InnoEnergy project “NEPTUNE” develops a floating Lidar buoy and a hindcast- and forecast model for wind- wave- and current measurements of offshore wind farms. In this paper just the lidar buoy is presented and discussed: Main challenges, the design ideas and the steps to develop, test and prototype this product, which – according to the KIC-InnoEnergy project idea – should be commercialized after the project end, foreseen for the end of 2014. KIC-InnoEnergy is funded from the European Institute of Technology, EIT.Peer ReviewedPostprint (published version

    X-ray microtomography analysis of the damage micromechanisms in 3D woven composites under low-velocity impact

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    3D woven composites reinforced with either S2 glass, carbon or a hybrid combination of both and containing either polyethylene or carbon z-yarns were tested under low-velocity impact. Different impact energies (in the range of 21–316 J) were used and the mechanical response (in terms of the impact strength and energy dissipated) was compared with that measured in high-performance, albeit standard, 2D laminates. It was found that the impact strength in both 2D and 3D materials was mainly dependent on the in-plane fiber fracture. Conversely, the energy absorption capability was primarily influenced by the presence of z-yarns, having the 3D composites dissipated over twice the energy than the 2D laminates, irrespective of their individual characteristics (fiber type, compaction degree, porosity, etc.). X-ray microtomography revealed that this improvement was due to the z-yarns, which delayed delamination and maintained the structural integrity of the laminate, promoting energy dissipation by tow splitting, intensive fiber breakage under the tup and formation of a plug by out-of-plane shear
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