1,430 research outputs found

    CFRP STRUCTURAL CAPACITORS: EFFECT OF DAMAGE AND MECHANICAL LOAD ON CAPACITANCE

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    Aim of this work is to study the effect of mechanical load and damages, on the performance of structural capacitors, made by CFRP composite laminates with a PET dielectric film (treated with sodium hydroxide) inserted at the laminate middle-plane. Such capacitors have been characterized by ILSS and tensile tests and the properties so estimated were compared to those of the simple CFRP. By measuring the capacitance before mechanical loading, under loading and after unloading, it has been observed that, due to the damage of the CFRP layers, proved also by proper fractographic analysis, at high strain level the capacitance decreases although it exhibits a complete recovery after unloading. Successive FEM analysis have been performed on structural capacitors to detect the interlaminar stress field and to implement a suitable criterion that can be used at the design stage to a reliable prediction of the failure load of such multifunctional CFRP composite materials

    Differential regulation of local mRNA dynamics and translation following long-term potentiation and depression

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    Decades of work have demonstrated that messenger RNAs (mRNAs) are localized and translated within neuronal dendrites and axons to provide proteins for remodeling and maintaining growth cones or synapses. It remains unknown, however, whether specific forms of plasticity differentially regulate the dynamics and translation of individual mRNA species. To address this, we targeted three individual synaptically localized mRNAs, CamkIIa, β-actin, Psd95, and used molecular beacons to track endogenous mRNA movements. We used reporters and CRISPR/Cas9 gene editing to track mRNA translation in cultured neurons. We found alterations in mRNA dynamic properties occurred during two forms of synaptic plasticity, long-term potentiation (cLTP) and depression (mGluR-LTD). Changes in mRNA dynamics following either form of plasticity resulted in an enrichment of mRNA in the vicinity of dendritic spines. Both the reporters and tagging of endogenous proteins revealed the transcript-specific stimulation of protein synthesis following cLTP or mGluR-LTD. As such, the plasticity-induced enrichment of mRNA near synapses could be uncoupled from its translational status. The enrichment of mRNA in the proximity of spines allows for localized signaling pathways to decode plasticity milieus and stimulate a specific translational profile, resulting in a customized remodeling of the synaptic proteome

    X-ray tomography data of compression tested unidirectional fibre composites with different off-axis angles

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    This data article contains lab-based micro-computed tomography (μCT) data of unidirectional (UD) non-crimp fabric (NCF) carbon fibre reinforced composite specimens that have been deformed by compression. The specimens contain UD fibres with off-axis angles of 0\ub0, 5\ub0, 10\ub0, 15\ub0 and 20\ub0 and the compression testing induces kink-band formation. This data formed the basis for the analysis of the influence of in-plane shear on kink-plane orientation as reported in Wilhelmsson et al. (Wilhelmsson et al., 2019)

    The omnivorous Tyrolean Iceman: colon contents (meat, cereals, pollen, moss and whipworm) and stable isotope analyses

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    The contents of the colon of the Tyrolean Iceman who lived Ga. 5300 years ago include muscle fibres, cereal remains, a diversity of pollen, and most notably that of the hop hornbeam (Ostrya carpinifolia) retaining cellular contents, as well as a moss leaf (Neckera complanata) and eggs of the parasitic whipworm (Trichuris trichiura). Based almost solely on stable isotope analyses and ignoring the work on the colon contents, two recently published papers on the Iceman's diet draw ill- founded conclusions about vegetarianism and even veganism. Neither the pollen nor the moss is likely to have been deliberately consumed as food by the Iceman. All the available evidence concerning the Iceman's broad-based diet is reviewed and the significance of the colon contents for matters other than assessment of food intake is outlined

    The switch-like expression of heme-regulated kinase 1 mediates neuronal proteostasis following proteasome inhibition

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    We examined the feedback between the major protein degradation pathway, the ubiquitin-proteasome system (UPS), and protein synthesis in rat and mouse neurons. When protein degradation was inhibited, we observed a coordinate dramatic reduction in nascent protein synthesis in neuronal cell bodies and dendrites. The mechanism for translation inhibition involved the phosphorylation of eIF2alpha, surprisingly mediated by eIF2alpha kinase 1, or heme-regulated kinase inhibitor (HRI). Under basal conditions, neuronal expression of HRI is barely detectable. Following proteasome inhibition, HRI protein levels increase owing to stabilization of HRI and enhanced translation, likely via the increased availability of tRNAs for its rare codons. Once expressed, HRI is constitutively active in neurons because endogenous heme levels are so low; HRI activity results in eIF2alpha phosphorylation and the resulting inhibition of translation. These data demonstrate a novel role for neuronal HRI that senses and responds to compromised function of the proteasome to restore proteostasis

    Multifunctional design, feasibility and requirements for structural power composites in future electric air taxis

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    This study investigates the viability of implementing multifunctional structural power composites in a four-seater air taxi, the CityAirbus. For a given specific energy of the power source, the cruise endurance can be approximately doubled by using structural power composites as opposed to conventional batteries. Replacing all the eligible composite mass and batteries with structural power composites can reduce the CityAirbus weight by 25%. To achieve the current design performance, the minimum required elastic modulus, strength, specific energy and power for the structural power composite are 54 GPa, 203 MPa, 74 Wh/kg and 376 W/kg, respectively: current state-of-the-art structural power composites are now approaching this level of performance. Hence, structural power composites are considered feasible for adoption in the urban air mobility sector and have the potential to improve endurance and facilitate commercialization. This paper also discusses several key challenges that must be addressed to realize the adoption of structural power composites in future electric air taxis

    Selective deactivation of gibberellins below the shoot apex is critical to flowering but not to stem elongation of Lolium

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    Gibberellins (GAs) cause dramatic increases in plant height and a genetic block in the synthesis of GA1 explains the dwarfing of Mendel's pea. For flowering, it is GA5 which is important in the long-day (LD) responsive grass, Lolium. As we show here, GA

    Robust numerical analysis of fibrous composites from X-ray computed tomography image data enabling low resolutions

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    X-ray computed tomography scans can provide detailed information about the state of the material after manufacture and in service. X-ray computed tomography aided engineering (XAE) was recently introduced as an automated process to transfer 3D image data to finite element models. The implementation of a structure tensor code for material orientation analysis in combination with a newly developed integration point-wise fibre orientation mapping allows an easy applicable, computationally cheap, fast, and accurate model set-up. The robustness of the proposed approach is demonstrated on a non-crimp fabric glass fibre reinforced composite for a low resolution case with a voxel size of 64 μm corresponding to more than three times the fibre diameter. Even though 99.8% of the original image data is removed, the simulated elastic modulus of the considered non-crimp fabric composite is only underestimated by 4.7% compared to the simulation result based on the original high resolution scan

    Neuromuscular responses to mild-muscle damaging eccentric exercise in a low glycogen state.

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    The aim of this study was to examine the effect of low muscle glycogen on the neuromuscular responses to maximal eccentric contractions. Fourteen healthy men (22±3years) performed single-leg cycling (20min at ∼75% maximal oxygen uptake (V̇O2 max); eight 90 s sprints at a 1:1 work-to-rest ratio (5% decrements from 90% to 55% V̇O2 max until exhaustion) the evening before 100 eccentric (1.57rads(-1)) with reduced (RED) and normal glycogen (NORM). Neuromuscular responses were measured during and up to 48h after with maximal voluntary and involuntary (twitch, 20Hz and 50Hz) isometric contractions. During eccentric contractions, peak torque decreased (RED: -16.1±2.5%; NORM: -6.2±5.1%) and EMG frequency increased according to muscle length. EMG activity decreased for RED only. After eccentric contractions, maximal isometric force was reduced up to 24h for NORM (-13.5±5.8%) and 48h for RED (-7.4±10.9%). Twelve hours after eccentric contractions, twitch force and the 20:50Hz ratio were decreased for RED but not for NORM. Immediate involuntary with prolonged voluntary force loss suggests that reduced glycogen is associated with increased susceptibility to mild muscle-damaging eccentric exercise with contributions of peripheral and central mechanisms to be different during recovery

    Health claims in the labelling and marketing of food products:: the Swedish food sector's Code of Practice in a European perspective

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    Since 1990 certain health claims in the labelling and marketing of food products have been allowed in Sweden within the food sector's Code of Practice. The rules were developed in close dialogue with the authorities. The legal basis was a decision by the authorities not to apply the medicinal products’ legislation to “foods normally found on the dinner table” provided the rules defined in the Code were followed. The Code of Practice lists nine well-established diet–health relationships eligible for generic disease risk reduction claims in two steps and general rules regarding nutrient function claims. Since 2001, there has also been the possibility for using “product-specific physiological claims (PFP)”, subject to premarketing evaluation of the scientific dossier supporting the claim. The scientific documentation has been approved for 10 products with PFP, and another 15 products have been found to fulfil the Code's criteria for “low glycaemic index”. In the third edition of the Code, active since 2004, conditions in terms of nutritional composition were set, i.e. “nutrient profiles”, with a general reference to the Swedish National Food Administration's regulation on the use of a particular symbol, i.e. the keyhole symbol. Applying the Swedish Code of practice has provided experience useful in the implementation of the European Regulation on nutrition and health claims made on foods, effective from 2007
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