546 research outputs found
Use of recycled carbon fibre as an additive in the manufacture of porous bricks more durable against salt crystallization
Within the framework of the Sustainable Development Goals of the Agenda 2030, the circular economy is being
promoted as a means of ensuring a sustainable use of resources and a reduction in the amount of waste produced.
The aim is to reduce the demand for often scarce raw materials through the continuous reuse, recycling and
regeneration of materials and products. This paper explores the use of carbon fibre from wind turbine blades as
an additive in the production of new efficient bricks. Clay mixes with 0, 5 and 10 wt% additive were fired at
three temperatures (800, 950 and 1100 ºC) and the fired bricks were analysed from mineralogical and physical
points of view to determine their suitability for use in the construction industry. The results show that carbon
fibre improves the durability of the bricks, which became 16 % more porous as the firing temperature increased.
However, the compressive strength of the bricks with 10 wt% carbon fibre was about 50 % lower than that of the
control bricks made without additive. It is interesting to note that the distribution of the carbon fibres within the
brick varies considerably and that they are shorter and wider in the core of the samples. These results could offer
an alternative line for new product development in the brick industry. The bricks tested here are an example of a
circular economy in which waste from one industrial process (wind turbine blades) is reused as an input in
another (brick manufacture). The environmental benefits achieved are twofold: reduced demand for clay and
recycling of decommissioned turbine blades, which are currently amassed in wind turbine graveyards.Funding for open access charge Universidad de Granada/CBUA.Junta de Andalucía Research Group
RNM179Research Project B-RNM-188-UGR20 of the Regional
Ministry of University, Research and Innovation of the Junta de Andalucía
and FEDER, a way of making Europ
25 Years of Self-Organized Criticality: Solar and Astrophysics
Shortly after the seminal paper {\sl "Self-Organized Criticality: An
explanation of 1/f noise"} by Bak, Tang, and Wiesenfeld (1987), the idea has
been applied to solar physics, in {\sl "Avalanches and the Distribution of
Solar Flares"} by Lu and Hamilton (1991). In the following years, an inspiring
cross-fertilization from complexity theory to solar and astrophysics took
place, where the SOC concept was initially applied to solar flares, stellar
flares, and magnetospheric substorms, and later extended to the radiation belt,
the heliosphere, lunar craters, the asteroid belt, the Saturn ring, pulsar
glitches, soft X-ray repeaters, blazars, black-hole objects, cosmic rays, and
boson clouds. The application of SOC concepts has been performed by numerical
cellular automaton simulations, by analytical calculations of statistical
(powerlaw-like) distributions based on physical scaling laws, and by
observational tests of theoretically predicted size distributions and waiting
time distributions. Attempts have been undertaken to import physical models
into the numerical SOC toy models, such as the discretization of
magneto-hydrodynamics (MHD) processes. The novel applications stimulated also
vigorous debates about the discrimination between SOC models, SOC-like, and
non-SOC processes, such as phase transitions, turbulence, random-walk
diffusion, percolation, branching processes, network theory, chaos theory,
fractality, multi-scale, and other complexity phenomena. We review SOC studies
from the last 25 years and highlight new trends, open questions, and future
challenges, as discussed during two recent ISSI workshops on this theme.Comment: 139 pages, 28 figures, Review based on ISSI workshops "Self-Organized
Criticality and Turbulence" (2012, 2013, Bern, Switzerland
Vertical Engineering for Large Brillouin Gain in Unreleased Silicon-Based Waveguides
[EN] Strong acousto-optic interaction in high-index waveguides and cavities generally requires the releasing of the high-index core to avoid mechanical leakage into the underlying low-index substrate. This complicates fabrication, limits thermalization, reduces the mechanical robustness, and hinders large-area optomechanical devices on a single chip. Here, we overcome this limitation by employing vertical photonic-phononic engineering to drastically reduce mechanical leakage into the cladding by adding a pedestal with specific properties between the core and the cladding. We apply this concept to a silicon-based platform, due to the remarkable properties of silicon to enhance optomechanical interactions and the technological relevance of silicon devices in multiple applications. Specifically, the insertion of a thick silicon nitride layer between the silicon guiding core and the silica substrate contributes to reducing gigahertz-frequency phonon leakage while enabling large values of the Brillouin gain in an unreleased platform. We numerically obtain values of the Brillouin gain around
300
(
W m
)
¿
1
for different configurations, which could be further increased by operation at cryogenic temperatures. These values should enable Brillouin-related phenomena in centimeter-scale waveguides or in more compact ring resonators. Our findings could pave the way toward large-area unreleased-cavity and waveguide optomechanics on silicon and other high-index photonic technologies.This work was supported by the European Commission (PHENOMEN Grant No. H2020-EU-713450), the Universitat Politecnica de Valencia (Grant No. PAID-01-169), the Ministerio de Ciencia, Innovacion y Universidades (Grants No. PGC2018-094490-B and No. PRX18/00126), and the Generalitat Valenciana (Grant No. PROMETEO/2019/123)Mercadé-Morales, L.; Korovin, AV.; Pennec, Y.; Ahopelto, J.; Djafari-Rouhani, B.; Martínez Abietar, AJ. (2021). Vertical Engineering for Large Brillouin Gain in Unreleased Silicon-Based Waveguides. Physical Review Applied. 15(3):1-9. https://doi.org/10.1103/PhysRevApplied.15.0340211915
Linear ubiquitin assembly complex regulates lung epithelial–driven responses during influenza infection
Influenza A virus (IAV) is among the most common causes of pneumonia-related death worldwide. Pulmonary epithelial cells are the primary target for viral infection and replication and respond by releasing inflammatory mediators that recruit immune cells to mount the host response. Severe lung injury and death during IAV infection result from an exuberant host inflammatory response. The linear ubiquitin assembly complex (LUBAC), composed of SHARPIN, HOIL-1L, and HOIP, is a critical regulator of NF-κB–dependent inflammation. Using mice with lung epithelial–specific deletions of HOIL-1L or HOIP in a model of IAV infection, we provided evidence that, while a reduction in the inflammatory response was beneficial, ablation of the LUBAC-dependent lung epithelial–driven response worsened lung injury and increased mortality. Moreover, we described a mechanism for the upregulation of HOIL-1L in infected and noninfected cells triggered by the activation of type I IFN receptor and mediated by IRF1, which was maladaptive and contributed to hyperinflammation. Thus, we propose that lung epithelial LUBAC acts as a molecular rheostat that could be selectively targeted to modulate the immune response in patients with severe IAV-induced pneumonia.Fil: Brazee, Patricia L.. Northwestern University; Estados UnidosFil: Morales Nebreda, Luisa. Northwestern University; Estados UnidosFil: Magnani, Natalia Daniela. Northwestern University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; ArgentinaFil: Garcia, Joe G. N.. University of Arizona; Estados UnidosFil: Misharin, Alexander V.. Northwestern University; Estados UnidosFil: Ridge, Karen M.. Northwestern University; Estados UnidosFil: Budinger, G.R. Scott. Northwestern University; Estados UnidosFil: Iwai, Kazuhiro. Kyoto University; JapónFil: Dada, Laura Andrea. Northwestern University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; ArgentinaFil: Sznajder, Jacob I.. Northwestern University; Estados Unido
Study of the Secondary Electron Yield in Dielectrics Using Equivalent Circuital Models
© 2018 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] Secondary electron emission has an important role on the triggering of the multipactor effect; therefore, its study and characterization are essential in radio-frequency waveguide applications. In this paper, we propose a theoretical model, based on equivalent circuit models, to properly understand charging and discharging processes that occur in dielectric samples under electron irradiation for secondary electron emission characterization. Experimental results obtained for Pt, Si, GaS, and Teflon samples are presented to verify the accuracy of the proposed model. Good agreement between theory and experiments has been found.The authors would like to thank the European High Power Space Materials Laboratory for its contribution-a laboratory funded by the European Regional Development Fund-a way of making Europe. Many thanks to the University of Valencia (Spain) for supporting this research activity with the internal program "Assistance for temporary stays of invited researchers within the framework of the Subprogramme Attraction of Talent 2015".Bañón, D.; Socuellamos, JM.; Mata-Sanz, R.; Mercadé-Morales, L.; Gimeno Martínez, B.; Boria Esbert, VE.; Raboso García-Baquero, D.... (2018). Study of the Secondary Electron Yield in Dielectrics Using Equivalent Circuital Models. IEEE Transactions on Plasma Science. 46(4):859-867. https://doi.org/10.1109/TPS.2018.2809602S85986746
Sample dilution and bacterial community composition influence empirical leucine-to-carbon conversion factors in surface waters of the world's oceans
Research articleThe transformation of leucine incorporation into prokaryotic carbon production
rates requires the use of either theoretical or empirically determined conversion factors. Empirical leucine-to-carbon conversion factors (eCFs) vary widely across
environments, and little is known about their potential controlling factors. We
conducted 10 surface seawater manipulation experiments across the world’s oceans, where the growth of the natural prokaryotic assemblages was promoted by filtration (i.e.
removal of grazers; F treatment) or filtration combined with dilution (i.e. relieving also
resource competition; FD treatment). The impact of sunlight exposure was also
evaluated in the FD treatments, and we did not find a significant effect on the eCFs. The
eCFs varied from 0.09 to 1.47 kg C mol Leu-1 and were significantly lower in the
filtered and diluted (FD) than in the filtered (F) treatments. Also, changes in bacterial
community composition during the incubations, as assessed by Automated Ribosomal
Intergenic Spacer Analysis (ARISA), were stronger in the FD than in the F treatments,
as compared to unmanipulated controls. Thus, we discourage the common procedure of
diluting samples (in addition to filtration) for eCFs determination. The eCFs in the
filtered treatment were negatively correlated with the initial chlorophyll a concentration,
picocyanobacterial abundance (mostly Prochlorococcus) and the percentage of heterotrophic prokaryotes with high nucleic acid content (%HNA). The latter two
variables explained 80% of the eCFs variability in the F treatment, supporting the view
that both Prochlorococcus and HNA prokaryotes incorporate leucine in substantial
amounts although resulting into relatively low carbon production rates in the oligotrophic ocean.En prensa3,829
Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program
The James Webb Space Telescope will revolutionize transiting exoplanet
atmospheric science due to its capability for continuous, long-duration
observations and its larger collecting area, spectral coverage, and spectral
resolution compared to existing space-based facilities. However, it is unclear
precisely how well JWST will perform and which of its myriad instruments and
observing modes will be best suited for transiting exoplanet studies. In this
article, we describe a prefatory JWST Early Release Science (ERS) program that
focuses on testing specific observing modes to quickly give the community the
data and experience it needs to plan more efficient and successful future
transiting exoplanet characterization programs. We propose a multi-pronged
approach wherein one aspect of the program focuses on observing transits of a
single target with all of the recommended observing modes to identify and
understand potential systematics, compare transmission spectra at overlapping
and neighboring wavelength regions, confirm throughputs, and determine overall
performances. In our search for transiting exoplanets that are well suited to
achieving these goals, we identify 12 objects (dubbed "community targets") that
meet our defined criteria. Currently, the most favorable target is WASP-62b
because of its large predicted signal size, relatively bright host star, and
location in JWST's continuous viewing zone. Since most of the community targets
do not have well-characterized atmospheres, we recommend initiating preparatory
observing programs to determine the presence of obscuring clouds/hazes within
their atmospheres. Measurable spectroscopic features are needed to establish
the optimal resolution and wavelength regions for exoplanet characterization.
Other initiatives from our proposed ERS program include testing the instrument
brightness limits and performing phase-curve observations.(Abridged)Comment: This is a white paper that originated from an open discussion at the
Enabling Transiting Exoplanet Science with JWST workshop held November 16 -
18, 2015 at STScI (http://www.stsci.edu/jwst/science/exoplanets). Accepted
for publication in PAS
Novel inhibitors of human glucose-6-phosphate dehydrogenase (HsG6PD) affect the activity and stability of the protein
Background: The pentose phosphate pathway (PPP) has received significant attention because of the role of NADPH and R-5-P in the maintenance of cancer cells, which are necessary for the synthesis of fatty acids and contribute to uncontrollable proliferation. The HsG6PD enzyme is the rate-limiting step in the oxidative branch of the PPP, leading to an increase in the expression levels in tumor cells; therefore, the protein has been proposed as a target for the development of new molecules for use in cancer. Methods: Through in vitro studies, we assayed the effects of 55 chemical compounds against recombinant HsG6PD. Here, we present the kinetic characterization of four new HsG6PD inhibitors as well as their functional and structural effects on the protein. Furthermore, molecular docking was performed to determine the interaction of the best hits with HsG6PD. Results: Four compounds, JMM-2, CCM-4, CNZ-3, and CNZ-7, were capable of reducing HsG6PD activity and showed noncompetitive and uncompetitive inhibition. Moreover, experiments using circular dichroism and fluorescence spectroscopy showed that the molecules affect the structure (secondary and tertiary) of the protein as well as its thermal stability. Computational docking analysis revealed that the interaction of the compounds with the protein does not occur at the active site. Conclusions: We identified two new compounds (CNZ-3 and JMM-2) capable of inhibiting HsG6PD that, compared to other previously known HsG6PD inhibitors, showed different mechanisms of inhibition. General significance: Screening of new inhibitors for HsG6PD with a future pharmacological approach for the study and treatment of cancer
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