266 research outputs found

    Highly Conductive Carbon Fiber Reinforced Concrete for Icing Prevention and Curing

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    This paper aims to study the feasibility of highly conductive carbon fiber reinforced concrete (CFRC) as a self-heating material for ice formation prevention and curing in pavements. Tests were carried out in lab ambient conditions at different fixed voltages and then introduced in a freezer at −15 °C. The specimens inside the freezer were exposed to different fixed voltages when reaching +5 °C for prevention of icing and when reaching the temperature inside the freezer, i.e., −15 °C, for curing of icing. Results show that this concrete could act as a heating element in pavements with risk of ice formation, consuming a reasonable amount of energy for both anti-icing (prevention) and deicing (curing), which could turn into an environmentally friendly and cost-effective deicing method.Authors want to acknowledge Generalitat Valenciana (PROMETEO/2013/035) for their economic support on this research, including funds for covering the costs to publish in open access

    Optimization of ultrasound-assisted liquefaction of solid digestate to produce bio-oil: Energy study and characterization

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    Among the possibilities for industrial waste valorization, liquefaction is gaining interest as it may provide alternative energy and high value-added products. In this context, this work focuses on the production of bio-oil through ultrasound (US)-assisted direct liquefaction. For the reaction, polyethylene glycol (PEG) and crude glycerol were selected. As this process is conducted by raising reaction temperature, US provided it, while shortening reaction time, through the cavitation phenomenon. For liquefaction reaction optimization, a response surface methodology (Box-Behnken design) was performed. As independent variables, US-amplitude, reaction time and solvent-to-biomass ratio were selected. On the other side, bio-oil yield, high calorific value (HCV) and energy consumption were chosen as dependent responses. Optimal results showed a bio-oil yield of 34.17% (reached in<20 min), HCV of 28.44 MJ/kg and energy consumption (US) of 11.477 kJ. Moreover, differences between predicted and experimental values were found to be negligible. Bio-oil was also characterized using Fourier transform infrared (FT-IR) and chromatography-mass spectrometry gas (GC–MS). Both techniques showed a profile rich in phenols and poly-oils, which can be used as precursors for industrial products, i.e. polymers. Finally, to check the impact of liquefaction on solid digestate, scanning electron microscopy (SEM) analysis was carried out. Results showed an increase in porosity, fragment and conglomerate. It may be concluded that the use of US as auxiliary energy in solid digestate liquefaction, to produce bio-oil, provides energy saving. Thus, the proposed valorization path aids consolidating the concept of circular economy through an efficient biorefinery model

    An extensive K-bentonite as an indicator of a super-eruption in northern Iberia 477 My ago

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    Zircon and monazite ID-TIMS U-Pb dating of four Lower Ordovician altered ash-fall tuff beds (K-Bentonites) in NW Iberia provided coetaneous ages of 477.5±1, 477±1.3 Ma, 477.2±1.1 Ma and 477.3±1 Ma, with a pooled concordia age of 477.2±0.74 Ma. A conservative estimation of the volume and mass of the studied K-bentonite beds (using data from the Cantabrian Zone) returns a minimum volume for the preserved deposits of ca. 37.5 km3 (Volcanic Explosivity Index - VEI = 6, Colossal). When considering other putative equivalent beds in other parts of Iberia and neighbouring realms the volume of ejecta associated to this event would make it reach the Supervolcanic-Apocalyptic status (VEI=8, >1000 km3). Contrary to most cases of this kind of gargantuan eruption events, the studied magmatic event took place in relation to continental margin extension and thinning and not to plate convergence. We speculate that a geochronologically coincident large caldera event observed in the geological record of NW Iberia could be ground zero of this super-eruption

    Обширные отложения K-бентонитов как индикатор супервзрыва в северной Иберии на уровне 477 миллионов лет назад

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    Zircon and monazite ID-TIMS U-Pb dating of four Lower Ordovician altered ash-fall tuff beds (K-Bentonites) in NW Iberia provided coetaneous ages of 477.5±1, 477±1.3 Ma, 477.2±1.1 Ma and 477.3±1 Ma, with a pooled concordia age of 477.2±0.74 Ma. A conservative estimation of the volume and mass of the studied K-bentonite beds (using data from the Cantabrian Zone) returns a minimum volume for the preserved deposits of ca. 37.5 km3 (Volcanic Explosivity Index - VEI = 6, Colossal). When considering other putative equivalent beds in other parts of Iberia and neighboring realms the volume of ejecta associated to this event would make it reach the Supervolcanic-Apocalyptic status (VEI=8, >1000 km3). Contrary to most cases of this kind of gargantuan eruption events, the studied magmatic event took place in relation to continental margin extension and thinning and not to plate convergence. We speculate that a geochronologically coincident large caldera event observed in the geological record of NW Iberia could be ground zero of this super-eruption

    Quantitative comparison of DNA methylation assays for biomarker development and clinical applications

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    DNA methylation patterns are altered in numerous diseases and often correlate with clinically relevant information such as disease subtypes, prognosis and drug response. With suitable assays and after validation in large cohorts, such associations can be exploited for clinical diagnostics and personalized treatment decisions. Here we describe the results of a community-wide benchmarking study comparing the performance of all widely used methods for DNA methylation analysis that are compatible with routine clinical use. We shipped 32 reference samples to 18 laboratories in seven different countries. Researchers in those laboratories collectively contributed 21 locus-specific assays for an average of 27 predefined genomic regions, as well as six global assays. We evaluated assay sensitivity on low-input samples and assessed the assays' ability to discriminate between cell types. Good agreement was observed across all tested methods, with amplicon bisulfite sequencing and bisulfite pyrosequencing showing the best all-round performance. Our technology comparison can inform the selection, optimization and use of DNA methylation assays in large-scale validation studies, biomarker development and clinical diagnostics

    Dynamic undocking and the quasi-bound state as tools for drug discovery

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    There is a pressing need for new technologies that improve the efficacy and efficiency of drug discovery. Structure-based methods have contributed towards this goal but they focus on predicting the binding affinity of protein–ligand complexes, which is notoriously difficult. We adopt an alternative approach that evaluates structural, rather than thermodynamic, stability. As bioactive molecules present a static binding mode, we devised dynamic undocking (DUck), a fast computational method to calculate the work necessary to reach a quasi-bound state at which the ligand has just broken the most important native contact with the receptor. This non-equilibrium property is surprisingly effective in virtual screening because true ligands form more-resilient interactions than decoys. Notably, DUck is orthogonal to docking and other ‘thermodynamic’ methods. We demonstrate the potential of the docking–undocking combination in a fragment screening against the molecular chaperone and oncology target Hsp90, for which we obtain novel chemotypes and a hit rate that approaches 40

    DNA methylation alterations in grade II- and anaplastic pleomorphic xanthoastrocytoma

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    Background: Pleomorphic xanthoastrocytoma (PXA) is a rare WHO grade II tumor accounting for less than 1% of all astrocytomas. Malignant transformation into PXA with anaplastic features, is unusual and correlates with poorer outcome of the patients. Methods: Using a DNA methylation custom array, we have quantified the DNA methylation level on the promoter sequence of 807 cancer-related genes of WHO grade II (n = 11) and III PXA (n = 2) and compared to normal brain tissue (n = 10) and glioblastoma (n = 87) samples. DNA methylation levels were further confirmed on independent samples by pyrosequencing of the promoter sequences. Results: Increasing DNA promoter hypermethylation events were observed in anaplastic PXA as compared with grade II samples. We further validated differential hypermethylation of CD81, HCK, HOXA5, ASCL2 and TES on anaplastic PXA and grade II tumors. Moreover, these epigenetic alterations overlap those described in glioblastoma patients, suggesting common mechanisms of tumorigenesis. Conclusions: Even taking into consideration the small size of our patient populations, our data strongly suggest that epigenome-wide profiling of PXA is a valuable tool to identify methylated genes, which may play a role in the malignant progression of PXA. These methylation alterations may provide useful biomarkers for decision-making in those patients with low-grade PXA displaying a high risk of malignant transformation

    DNA methylation alterations in grade II- and anaplastic pleomorphic xanthoastrocytoma

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    BACKGROUND: Pleomorphic xanthoastrocytoma (PXA) is a rare WHO grade II tumor accounting for less than 1% of all astrocytomas. Malignant transformation into PXA with anaplastic features, is unusual and correlates with poorer outcome of the patients. METHODS: Using a DNA methylation custom array, we have quantified the DNA methylation level on the promoter sequence of 807 cancer-related genes of WHO grade II (n = 11) and III PXA (n = 2) and compared to normal brain tissue (n = 10) and glioblastoma (n = 87) samples. DNA methylation levels were further confirmed on independent samples by pyrosequencing of the promoter sequences. RESULTS: Increasing DNA promoter hypermethylation events were observed in anaplastic PXA as compared with grade II samples. We further validated differential hypermethylation of CD81, HCK, HOXA5, ASCL2 and TES on anaplastic PXA and grade II tumors. Moreover, these epigenetic alterations overlap those described in glioblastoma patients, suggesting common mechanisms of tumorigenesis. CONCLUSIONS: Even taking into consideration the small size of our patient populations, our data strongly suggest that epigenome-wide profiling of PXA is a valuable tool to identify methylated genes, which may play a role in the malignant progression of PXA. These methylation alterations may provide useful biomarkers for decision-making in those patients with low-grade PXA displaying a high risk of malignant transformation

    Probing the quantum-gravity realm with slow atoms

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    For the study of Planck-scale modifications of the energy-momentum dispersion relation, which had been previously focused on the implications for ultrarelativistic (ultrafast) particles, we consider the possible role of experiments involving nonrelativistic particles, and particularly atoms. We extend a recent result establishing that measurements of "atom-recoil frequency" can provide insight that is valuable for some theoretical models. And from a broader perspective we analyze the complementarity of the nonrelativistic and the ultrarelativistic regimes in this research area.Comment: LaTex, 13 page

    Thermoregulating gypsums by using nanoencapsulated phase change material slurry

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    Thermoregulating composites were produced by using a thermoregulating slurry (NPCS) containing nanoencapsulated phase change material (NPCM) from poly(styrene-co-divinylbenzene) as shell and the commercial paraffin Rubitherm®RT27 as core material. These composites were synthesized by using the constitutive water of the slurry as setting water and changing the NPCM/Hemihydrate (NPCM/Hem) mass ratio within 0.0–0.41. It was found that nanoparticles were uniformly dispersed into the gypsum, and the gypsum crystal morphology was tuned by the addition of the slurry. Attending to the thermal properties, these materials can work either as insulating or thermal energy storage materials, decreasing the thermal conductivity up to ~ 50%, whereas the thermal energy storage (TES) capacity is enlarged in a ~ 140%, respect to the pure gypsum, when the maximum NPCM/Hem mass ratio was used. This composite had a latent heat of 30.2 J g−1 and a heat capacity of equivalent 3.5 J g−1 K−1. Composites from a NPCM/Hem mass ratio up to 0.15 satisfied European mechanical standard EN 13,279–1 for gypsum binders and gypsum plasters and all of them, presented a bulk density higher than 0.60 g cm−3. The addition of a 41% in mass of nanocapsules allowed to save 13.5 kWh m−3 and, reducing the CO2 emissions up to 3.4 kg of CO2 per operating cycle. The use of this new material would lead to significant energy and economic savings, as well as a considerable reduction in the emission of polluting gases into the atmosphere.Los compuestos termorreguladores se produjeron utilizando una suspensión termorreguladora (NPCS) que contenía material de cambio de fase nanoencapsulado (NPCM) de poli(estireno-co-divinilbenceno) como cubierta y la parafina comercial Rubitherm®RT27 como material central. Estos compuestos se sintetizaron usando el agua constitutiva de la suspensión como agua de fraguado y cambiando la relación de masa NPCM/Hemihidrato (NPCM/Hem) entre 0,0 y 0,41. Se encontró que las nanopartículas se dispersaron uniformemente en el yeso, y la morfología del cristal de yeso se ajustó mediante la adición de la suspensión. Atendiendo a las propiedades térmicas, estos materiales pueden funcionar como materiales aislantes o de almacenamiento de energía térmica, disminuyendo la conductividad térmica hasta ~ 50%, mientras que la capacidad de almacenamiento de energía térmica (TES) se amplía en un ~ 140%, respecto a la pura. yeso, cuando se utilizó la máxima relación de masa NPCM/Hem. Este material compuesto tenía un calor latente de 30,2 J g−1 y una capacidad calorífica equivalente a 3,5 J g−1 K−1. Los composites a partir de una relación másica NPCM/Hem hasta 0,15 cumplieron con la norma mecánica europea EN 13.279–1 para aglomerantes de yeso y revoques de yeso y todos ellos, presentaron una densidad aparente superior a 0,60 g cm−3. La adición de un 41% en masa de nanocápsulas permitió ahorrar 13,5 kWh m−3 y, reducir las emisiones de CO2 hasta 3,4 kg de CO2 por ciclo de operación. La utilización de este nuevo material supondría un importante ahorro energético y económico, así como una considerable reducción de la emisión de gases contaminantes a la atmósfera
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