2,005 research outputs found
Post-synthetic ligand exchange as a route to improve the affinity of ZIF-67 towards CO2
The Zeolitic Imidazolate Framework 67 (ZIF-67) is a highly promising material owing to its exceptional thermal stability, large specific surface area, cost-effectiveness, and versatile applications. One of the potential applications of ZIF-67 is gas separation processes, among which the separation of CO2/CH4 mixtures has attracted great interest nowadays in the biogas sector. However, when it comes to CO2/CH4 separation, ZIF-67 falls short as it lacks the desired selectivity despite its high adsorption capacity. This limitation arises from its relatively low affinity towards CO2. In this study, we have addressed this issue by partially exchanging the ligand of ZIF-67, specifically replacing 2-methylimidazole with 1,2,4 (1H) triazole, which introduces an additional nitrogen atom. This modification resulted in ZIF-67 showing significantly enhanced affinity towards CO2 and, as a result, greater selectivity towards CO2 over CH4. The modified materials underwent thorough characterization using various techniques, and their adsorption capacity was evaluated through high-pressure adsorption isotherms. Furthermore, their separation performance was assessed using the Ideal Solution Adsorption Theory, which provided valuable insights into their potential for efficient gas separation.Financial support from Ministerio de Ciencia e Innovación (Spain, PID2020-116998RB-I00) is gratefully acknowledged. Conselleria de Innovacion, Universidades, Ciencia y Sociedad Digital (CIPROM/2021/022). This study forms part of the Advanced Materials programme and was supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17.I1) and by Generalitat Valenciana
The evolution of the subcontinental mantle beneath the Central Iberian Zone: Geochemical tracking of its mafic magmatism from the Neoproterozoic to the Cenozoic
Continental lithosphere is modified over eons in response to large-scale tectonic processes, such as rifting and collisions. The lithospheric mantle beneath central Iberia was affected by multiple Neoproterozoic to Cenozoic events including two orogenic cycles. However, the details of this evolution, and the relationship of the Iberian lithosphere to that beneath central Europe remains poorly constrained. We have compiled a trace element and isotope (Sr-Nd-Pb) data set (n = 230) regarding the main ten mafic magmatic episodes that intruded the central-western Iberia basement during a 575 Ma age range. In this long period, two orogenic events with accompanying mafic calc-alkaline magmatism (Cadomian and Variscan cycles) were followed by eight intraplate, alkaline or tholeiitic, magmatic inputs. The two orogenic episodes have subordinate mafic intrusions associated to a more voluminous felsic magmatism, which highlights both the major intracrustal recycling promoted and the significant crustal thickening accompanying these convergence tectonic events. Nevertheless, only minor crustal subduction signatures within deep mantle are observed in mafic magmas or mantle xenoliths after those two orogenic cycles, and the existence of an old (pre-Neoproterozoic) enriched subcontinental mantle beneath central Iberia is suggested. Mantle-derived magmas from central European basement terranes (Bohemian to Armorican-French Massif Central massifs) show a marked contrast of geochemical tracers during the same long time record. They show more juvenile and depleted mantle sources during the pre-Variscan times indicating their farther distance to continental Gondwana than the studied central Iberian terrane. Thus, the change in Nd isotopes and model ages associated with the Variscan orogeny is more abrupt in central European terranes. This collisional event was followed by the arrival of broadly similar mafic magmas in both southwestern and central European terranes, implying substantial crust-mantle interaction across a wide geographical area. The post-Variscan mafic magmatism, mainly from Cretaceous time, suggests a lithospheric mantle rejuvenation by widespread asthenospheric upwelling throughout these western circum-Mediterranean areas. However, the presence of minor episodes of intraplate K-rich alkaline magmatism involving enriched lithospheric mantle sources in the southernmost Mediterranean Europe marks a contrast, suggesting a complex lithospheric/asthenospheric mantle flow regime in these areas during post-collisional convergence between Africa and Eurasia
Priority areas for conservation alone are not a good proxy for predicting the impact of renewable energy expansion
Non peer reviewe
High-quality single-crystalline epitaxial regrowth on pulsed laser melting of Ti implanted GaAs
We present a detailed investigation on the formation of supersaturated GaAs using Ti+ implantation followed by
nanosecond Pulsed Laser Melting (PLM). We have synthesized high-crystal quality supersaturated GaAs layers with concentrations of Ti above the insulator to metal transition (Mott limit). The Ti-implanted concentration depth profiles after PLM obtained by Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) show a redistribution of Ti impurities within the first hundred nanometers and
superficial concentration up to 1 × 1021 redistr
cm-3. Raman spectroscopy of these Ti supersaturated, and regrown GaAs samples shows a sharp crystalline peak and tensile strain due to the Ti lattice incorporation. Scanning Transmission Electron Microscopy (STEM) and high-resolution Transmission Electron Microscopy (TEM) images show a good GaAs crystallinity after the PLM process. Energy-Dispersive X-ray Spectroscopy (EDS) reveals an enhanced Ti signal inside bubble-like structures and an appearance of interface oxide layer with all processed samples
Methionine Cycle Rewiring by Targeting miR-873-5p Modulates Ammonia Metabolism to Protect the Liver from Acetaminophen
Drug-induced liver injury (DILI) development is commonly associated with acetaminophen (APAP) overdose, where glutathione scavenging leads to mitochondrial dysfunction and hepatocyte death. DILI is a severe disorder without effective late-stage treatment, since N-acetyl cysteine must be administered 8 h after overdose to be efficient. Ammonia homeostasis is altered during liver diseases and, during DILI, it is accompanied by decreased glycine N-methyltransferase (GNMT) expression and S-adenosylmethionine (AdoMet) levels that suggest a reduced methionine cycle. Anti-miR-873-5p treatment prevents cell death in primary hepatocytes and the appearance of necrotic areas in liver from APAP-administered mice. In our study, we demonstrate a GNMT and methionine cycle activity restoration by the anti-miR-873-5p that reduces mitochondrial dysfunction and oxidative stress. The lack of hyperammoniemia caused by the therapy results in a decreased urea cycle, enhancing the synthesis of polyamines from ornithine and AdoMet and thus impacting the observed recovery of mitochondria and hepatocyte proliferation for regeneration. In summary, anti-miR-873-5p appears to be an effective therapy against APAP-induced liver injury, where the restoration of GNMT and the methionine cycle may prevent mitochondrial dysfunction while activating hepatocyte proliferative response.We thank Ministerio de Ciencia e Innovación, Programa Retos-Colaboración RTC2019-
007125-1 (for J.S. and M.L.M.-C.); Instituto de Salud Carlos III: Proyectos de Investigación en Salud
DTS20/00138 (for J.S. and M.L.M.-C.), PI20/00690 (for R.J.) and PT20/000127 (for M.I.L.); CIBERehd:
EHD21TRF01/2022 (to M.L.M.-C.); Departamento de Industria del Gobierno Vasco (for M.L.M.-C.);
Ministerio de Ciencia, Innovación y Universidades MICINN: PID2020-117116RB-I00 and RTI2018-
096759-1-100 integrado en el Plan Estatal de Investigación Cientifica y Técnica y Innovación, cofinanciado con Fondos FEDER (for M.L.M.-C. and T.C.D., respectively); BIOEF (Basque Foundation
for Innovation and Health Research); Asociación Española contra el Cáncer (AECC) (to M.L.M.-C.,
T.C.D.); AECC: GCTRA18006CARR (to A.C.); Fundación Científica de la Asociación Española Contra
el Cancer (AECC Scientific Foundation) Rare Tumor Calls 2017 (for M.L.M.); La Caixa Foundation Program (for M.L.M.); BFU2015-70067-REDC, BFU2016-77408-R and BES-2017-080435 (MINECO/FEDER,
UE); Ministerio de Ciencia, Innovación y universidades PID2019-108787RB-100 (to A.C.), PID2019-
109055RB-I00 (L.A.M.-C.), PID2020-117941RB-100 (to F.J.C.); Spanish Ministry of Economy and Competitiveness Grants BFU2013-47531-R and BFU2016-77408-R (L.A.M.-C.) and the FIGHT-CNNM2
project from the EJP RD Joint Transnational Call (JTC2019) (Ref. AC19/00073) (for L.A.M.-C.); Comunidad de Madrid: EXOHEP-CM S2017/BMD-3727 and NanoLiver-CM Y2018/NMT-4949 co-funded
by European Structural and Investment Fund and COST Action CA17112 (to F.J.C.); Vencer el Cáncer
Foundation (to A.C.); European Research Council: Consolidator Grant 819242 (to A.C.); CIBERONC
and CIBERehd were funded by the Instituto de Salud Carlos III and Cofunded by FEDER funds. Partial funding for open access charge: Universidad de Málag
Quantifying stratospheric biases and identifying their potential sources in subseasonal forecast systems
The stratosphere can be a source of predictability for surface weather on timescales of several weeks to months. However, the potential predictive skill gained from stratospheric variability can be limited by biases in the representation of stratospheric processes and the coupling of the stratosphere with surface climate in forecast systems. This study provides a first systematic identification of model biases in the stratosphere across a wide range of subseasonal forecast systems.
It is found that many of the forecast systems considered exhibit warm global-mean temperature biases from the lower to middle stratosphere, too strong/cold wintertime polar vortices, and too cold extratropical upper-troposphere/lower-stratosphere regions. Furthermore, tropical stratospheric anomalies associated with the Quasi-Biennial Oscillation tend to decay toward each system\u27s climatology with lead time. In the Northern Hemisphere (NH), most systems do not capture the seasonal cycle of extreme-vortex-event probabilities, with an underestimation of sudden stratospheric warming events and an overestimation of strong vortex events in January. In the Southern Hemisphere (SH), springtime interannual variability in the polar vortex is generally underestimated, but the timing of the final breakdown of the polar vortex often happens too early in many of the prediction systems.
These stratospheric biases tend to be considerably worse in systems with lower model lid heights. In both hemispheres, most systems with low-top atmospheric models also consistently underestimate the upward wave driving that affects the strength of the stratospheric polar vortex. We expect that the biases identified here will help guide model development for subseasonal-to-seasonal forecast systems and further our understanding of the role of the stratosphere in predictive skill in the troposphere
Differential branching fraction and angular analysis of the decay B0→K∗0μ+μ−
The angular distribution and differential branching fraction of the decay B 0→ K ∗0 μ + μ − are studied using a data sample, collected by the LHCb experiment in pp collisions at s√=7 TeV, corresponding to an integrated luminosity of 1.0 fb−1. Several angular observables are measured in bins of the dimuon invariant mass squared, q 2. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q20=4.9±0.9GeV2/c4 , where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions
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