414 research outputs found

    The Impact of Medium Chain and Polyunsaturated ω-3-Fatty Acids on Amyloid-β Deposition, Oxidative Stress and Metabolic Dysfunction Associated with Alzheimer’s Disease

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    Alzheimer’s disease (AD), the most common cause of dementia in the elderly population, is closely linked to a dysregulated cerebral lipid homeostasis and particular changes in brain fatty acid (FA) composition. The abnormal extracellular accumulation and deposition of the peptide amyloid-β (Aβ) is considered as an early toxic event in AD pathogenesis, which initiates a series of events leading to neuronal dysfunction and death. These include the induction of neuroinflammation and oxidative stress, the disruption of calcium homeostasis and membrane integrity, an impairment of cerebral energy metabolism, as well as synaptic and mitochondrial dysfunction. Dietary medium chain fatty acids (MCFAs) and polyunsaturated ω-3-fatty acids (ω-3-PUFAs) seem to be valuable for disease modification. Both classes of FAs have neuronal health-promoting and cognition-enhancing properties and might be of benefit for patients suffering from mild cognitive impairment (MCI) and AD. This review summarizes the current knowledge about the molecular mechanisms by which MCFAs and ω-3-PUFAs reduce the cerebral Aβ deposition, improve brain energy metabolism, and lessen oxidative stress levels

    Towards the Integration of Power-Indexed Formulations in Multi-Architecture Connected Facility Location Problems for the Optimal Design of Hybrid Fiber-Wireless Access Networks

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    Urban access networks are the external part of worldwide networks that make telecommunication services accessible to end users and represent a critical part of the infrastructures of modern cities. An important recent trend in urban access networks is the integration of fiber and wireless networks, leading to so-called fiber-wireless (Fi-Wi) networks. Fi-Wi networks get the best of both technologies, namely the high capacity offered by optical fiber networks and the mobility and ubiquity offered by wireless networks. The optimal design of fiber and wireless networks has been separately extensively studied. However, there is still a lack of mathematical models and algorithms for the integrated design problem. In this work, we propose a new Power-Indexed optimization model for the 3-architecture Connected Facility Location Problem arising in the design of urban telecommunication access networks. The new model includes additional power-indexed variables and constraints to represent the signal-to-interference formulas expressing wireless signal coverage. To solve the problem, which can prove very hard even for a state-of-the art optimization solver, we propose a new heuristic that combines a probabilistic variable fixing procedure, guided by (tight) linear relaxations, with an MIP heuristic, corresponding to an exact very large neighborhood search. Computational experiments on realistic instances show that our heuristic can find solutions of much higher quality than a state-of-the-art solver

    The medium-chain fatty acid decanoic acid reduces oxidative stress levels in neuroblastoma cells

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    Enhanced oxidative stress is a contributing factor in the pathogenesis of several neurodegenerative disorders such as Alzheimer´s disease. Beneficial effects have been demonstrated for medium-chain fatty acids (MCFAs) nutritionally administered as medium-chain triglycerides (MCTs) or coconut oil (CO). The observed effects on cognitive impairment are generally attributed to the hepatic metabolism of MCFAs, where resulting ketone bodies serve as an alternate energy source to compensate for the impaired glucose utilisation in the human brain. Here we show that the saturated MCFA decanoic acid (10:0) reduces the oxidative stress level in two different neuroblastoma cell lines. Phosphatidylcholine (PC) containing decanoic acid (10:0) (PC10:0/10:0) reduced the cellular H2O2 release in comparison to solvent, L-α-Glycerophosphorylcholine and PC containing the long-chain fatty acid (LCFA) arachidic acid (20:0). This effect seems to be at least partially based on an upregulation of catalase activity, independent of alterations in catalase gene expression. Further, PC10:0/10:0 decreased the intracellular oxidative stress level and attenuated the H2O2-induced cell death. It did not affect the level of the ketone body β-hydroxybutyrate (βHB). These results indicate that decanoic acid (10:0) and possibly MCFAs in general directly reduce oxidative stress levels independent of ketone levels and thus may promote neuronal health

    The Aspartate Aminotransferase-P2 Gene from Lupinus angustifolius

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    3D Tunnel Inspection with Photogrammetric and Hybrid Systems

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    The trend in tunnel assessment is towards comprehensive 3D measurement, either based on high quality digital imagery (photogrammetric systems) or the combination of laser and photo systems (hybrid systems). With digital 3D data, quantification and categorization of damage to the tunnel surface as well as the determination of thickness or volumes of layers (e.g. shotcrete) can performed in a comprehensive, fast and economic way. The faster such tunnel assessment can be executed on site, the lower are the tunnel block times and environmental impairments related to the building measures. The costs for the operating companies can be significantly reduced as well as the personnel efforts and risks of accidents. Furthermore, tunnel safety is increased due to faster test cycles which result in a more comprehensive overall monitoring. Please click Additional Files below to see the full abstract

    The Impact of Vitamin E and Other Fat-Soluble Vitamins on Alzheimer´s Disease

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    Alzheimer’s disease (AD) is the most common cause of dementia in the elderly population, currently affecting 46 million people worldwide. Histopathologically, the disease is characterized by the occurrence of extracellular amyloid plaques composed of aggregated amyloid-β (Aβ) peptides and intracellular neurofibrillary tangles containing the microtubule-associated protein tau. Aβ peptides are derived from the sequential processing of the amyloid precursor protein (APP) by enzymes called secretases, which are strongly influenced by the lipid environment. Several vitamins have been reported to be reduced in the plasma/serum of AD-affected individuals indicating they have an impact on AD pathogenesis. In this review we focus on vitamin E and the other lipophilic vitamins A, D, and K, and summarize the current knowledge about their status in AD patients, their impact on cognitive functions and AD risk, as well as their influence on the molecular mechanisms of AD. The vitamins might affect the generation and clearance of Aβ both by direct effects and indirectly by altering the cellular lipid homeostasis. Additionally, vitamins A, D, E, and K are reported to influence further mechanisms discussed to be involved in AD pathogenesis, e.g., Aβ-aggregation, Aβ-induced neurotoxicity, oxidative stress, and inflammatory processes, as summarized in this article

    Fast Zonal Field Dynamo in Collisionless Kinetic Alfven Wave Turbulence

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    The possibility of fast dynamo action by collisionless kinetic Alfven Wave turbulence is demonstrated. The irreversibility necessary to lock in the generated field is provided by electron Landau damping, so the induced electric field does not vanish with resistivity. Mechanisms for self-regulation of the system and the relation of these results to the theory of alpha quenching are discussed. The dynamo-generated fields have symmetry like to that of zonal flows, and thus are termed zonal fields

    Electrostatic sensor modeling for torque measurements

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    Torque load measurements play an important part in various engineering applications, as for automotive industry, in which the drive torque of a motor has to be determined. A widely used measuring method are strain gauges. A thin flexible foil, which supports a metallic pattern, is glued to the surface of the object the torque is being applied to. In case of a deformation due to the torque load, the change in the electrical resistance is measured. With the combination of constitutive equations the applied torque load is determined by the change of electrical resistance. The creep of the glue and the foil material, together with the temperature and humidity dependence, may become an obstacle for some applications Kapralov and Fesenko(1984). Thus, there have been optical and magnetical, as well as capacitive sensors introduced ). This paper discusses the general idea behind an electrostatic capacitive sensor based on a simple draft of an exemplary measurement setup. For better understanding an own electrostatical, geometrical and mechanical model of this setup has been developed
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