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Carbon isotopes of graphite:Implications on fluid history

Geoscience Frontiers 2012年第2期3卷 197-207页

作者： F.j.Luque E.crespo-Feo j.F.Barrenechea L.Ortega Departamento de Cristalografía y Mineralogía Facultad de Geología Universidad Complutense de Madrid 28040 MadridSpain Instituto de Geociencias(UCM-CSIC) Jos Antonio Novais 228040 MadridSpain Departamento de Cristalografia y Mineralogia Facultad de Geología Universidad Complutense de Madrid28040 MadridSpain Departamento de Cristalografía y Mineralogía Facultad de Geología Universidad Complutense de Madrid28040 MadridSpain

Stable carbon isotope geochemistry provides important information for the recognition of funda- mental isotope exchange processes related to the movement of carbon in the lithosphere and permits the elab- oration of models for the global carbon cycle. Carbon isotope ratios in fluid-deposited graphite are powerful tools for unravelling the ultimate origin of carbon （organic matter, mantle, or carbonates） and help to constrain the fluid history and the mechanisms involved in graphite deposition. Graphite precipitation in fluid-deposited occurrences results from C02- and/or CH4-bearing aqueous fluids. Fluid flow can be considered as both a closed （without replenishment of the fluid） or an open system （with renewal of the fluid by successive fluid batches）. In closed systems, carbon isotope systematics in graphite is mainly governed by Rayleigh precipi- tation and/or by changes in temperature affecting the fractionation factor between fluid and graphite. Such processes result in zoned graphite crystals or in successive graphite generations showing, in both cases, isotopic variation towards progressive 13C or 12C enrichment （depending upon the dominant carbon phase in the fluid, C02 or CH4, respectively）. In open systems, in which carbon is episodically introduced along the fracture systems, the carbon systematics is more complex and individual graphite crystals may display oscillatory zoning because of Rayleigh precipitation or heterogeneous variations of 613C values when mixing of fluids or changes in the composition of the fluids are the mechanisms responsible for graphite precipitation.

关键词： Graphite Carbon isotopes Crust C-O-H fluids

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Temporal dynamics of neonatal hypoxic-ischemic encephalopathy injuries on magnetic resonance imaging

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Neural Regeneration Research 2025年第11期20卷 3144-3150页

作者： Holly Flyger Samantha j.Holdsworth Alistair j.Gunn Laura Bennet Hamid Abbasi Mātai Medical Research Institute Tairāwhiti GisborneNew Zealand Department of Anatomy&Medical Imaging Faculty of Medical and Health SciencesThe University of AucklandAucklandNew Zealand Center for Brain Research The University of AucklandAucklandNew Zealand Auckland Bioengineering Institute The University of AucklandAucklandNew Zealand

Moderate to severe perinatal hypoxic-ischemic encephalopathy occurs in~1 to 3/1000 live births in high-income countries and is associated with a significant risk of death or neurodevelopmental *** assessment is important to help identify highrisk infants,to help families,and to support appropriate interventions.A wide range of monitoring tools is available to assess changes over time,including urine and blood biomarkers,neurological examination,and *** present,magnetic resonance imaging is unique as although it is expensive and not suited to monitoring the early evolution of hypoxic-ischemic encephalopathy by a week of life it can provide direct insight into the anatomical changes in the brain after hypoxic-ischemic encephalopathy and so offers strong prognostic information on the long-term outcome after hypoxic-ischemic *** review investigated the temporal dynamics of neonatal hypoxic-ischemic encephalopathy injuries,with a particular emphasis on exploring the correlation between the prognostic implications of magnetic resonance imaging scans in the first week of life and their relationship to long-term outcome prediction,particularly for infants treated with therapeutic hypothermia.A comprehensive literature search,from 2016 to 2024,identified 20 pertinent *** review highlights that while the optimal timing of magnetic resonance imaging scans is not clear,overall,it suggests that magnetic resonance imaging within the first week of life provides strong prognostic *** challenges limit the timing consistency,particularly the need for intensive care and clinical ***,although most reports examined the prognostic value of scans taken between 4 and 10 days after birth,there is evidence from small numbers of cases that,at times,brain injury may continue to evolve for weeks after *** suggests that in the future it will be important to explore a wider range of times after hypo

关键词： magnetic resonance imaging neonatal hypoxic-ischemic encephalopathy neurodevelopmental outcomes prognostic biomarkers in neuroimaging scan timing therapeutic hypothermia

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Interaction of silver nanoparticles with mediterranean agricultural soils: Lab-controlled adsorption and desorption studies

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journal of Environmental Sciences 2019年第9期31卷 205-216页

作者： Laura Torrent Eva Margui Ignasi Queralt Manuela hidalgo Monica Iglesias Department of Chemistry University of Girona C/M. Aurelia Capmany 69 17003 Girona Spain Institute of Environmental Assessment and Water Research (IDAEA-CSIC) C. Jordi Girona 28-26 08034 Barcelona Spain

The production of silver nanoparticles(AgNPs) has increased tremendously during recent years due to their antibacterial and physicochemical properties. As a consequence, these particles are released inevitably into the environment, with soil being the main sink of disposal. Soil interactions have an effect on AgNP mobility, transport and bioavailability. To understand AgNP adsorption processes, lab-controlled kinetic studies were *** tests performed with five different Mediterranean agricultural soils showed that cation exchange capacity and electrical conductivity are the main parameters controlling the adsorption processes. The adsorption kinetics of different sized(40, 75, 100 and 200 nm)and coated(citrate, polyvinylpyrrolidone and polyethyleneglycol(PEG)) AgNPs indicated that these nanoparticle properties have also an effect on the adsorption *** assess the mobility and bioavailability of AgNPs and to determine if their form is maintained during adsorption/desorption processes, loaded soils were submitted to leaching tests three weeks after batch adsorption studies. The DIN 38414-S4 extraction method indicated that AgNPs were strongly retained on soils, and single-particle inductively coupled plasma mass spectrometry confirmed that silver particles maintained their nanoform, except for 100 nm PEG-AgNPs and 40 nm citrate-coated AgNPs. The DTPA(diethylenetriaminepentaacetic acid) leaching test was more effective in extracting silver,but there was no presence of AgNPs in almost all of these leachates.

关键词： Silver nanoparticles Agricultural soils Sorption kinetics Leaching tests Single-particle inductively coupled plasma mass spectrometry

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Thermo-electro-mechanical microstructural interdependences in conductive thermoplastics

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npj Computational Materials 2023年第1期9卷 955-965页

作者： javier crespo-Miguel Sergio Lucarini Angel Arias Daniel Garcia-Gonzalez Department of Continuum Mechanics and Structural Analysis Universidad Carlos III de MadridAvda.de la Universidad 3028911 LeganésMadridSpain Department of Civil and Environmental Engineering Imperial College of LondonSouth Kensington CampusLondon SW72AZUK

Additive manufacturing has enabled the design of thermoplastic components that provide structural support,electrical conductivity and heat generation modulated by mechanical *** mechanisms and interplays that govern the material response at the microstructural level remain,however,***,we develop an experimental method to characterise conductive filaments from a combined mechanical,electrical and thermal *** approach is used to unravel exciting material interplays of conductive polylactic *** overcome experimental limitations that prevent a complete microstructural analysis of the problem,we develop a full-field homogenisation framework and implement it for finite *** framework accounts for viscoplasticity,electrical and thermal conduction,convection and heat generation via joule effect,as well as for the interdependences between *** experimental validation,the framework is applied to virtually optimise fabrication requirements to obtain desired properties in final products,i.e.,stiffer products,filaments with higher conductivities or with better sensing capabilities.

关键词： conductive electrical overcome

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Discretized Miller approach to assess effects on boundary layer ingestion induced distortion

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Chinese journal of Aeronautics 2017年第1期30卷 235-248页

作者： Esteban Valencia Víctor hidalgo Devaiah Nalianda Laskaridis Panagiotis Riti Singh Departamento de Ingeniería Mecánica Facultad de Ingeniería Mecánica Escuela Politécnica Nacional Ladron de Guevara E11-253 Quito 17-01-2759 Ecuador School of Engineering Cranfield University Bedford MK430AL United Kingdom

The performance of propulsion configurations with boundary layer ingestion（BLI） is affected to a large extent by the level of distortion in the inlet flow field. Through flow methods and parallel compressor have been used in the past to calculate the effects of this aerodynamic integration issue on the fan performance; however high-fidelity through flow methods are computationally expensive, which limits their use at preliminary design stage. On the other hand, parallel compressor has been developed to assess only circumferential distortion. This paper introduces a discretized semi-empirical performance method, which uses empirical correlations for blade and performance calculations. This tool discretizes the inlet region in radial and circumferential directions enabling the assessment of deterioration in fan performance caused by the combined effect of both distortion patterns. This paper initially studies the accuracy and suitability of the semiempirical discretized method by comparing its predictions with CFD and experimental data for a baseline case working under distorted and undistorted conditions. Then a test case is examined,which corresponds to the propulsor fan of a distributed propulsion system with BLI. The results obtained from the validation study show a good agreement with the experimental and CFD results under design point conditions.

关键词： BLI Correlations Distortion Embedded propulsors Empirical Mean-line analysis Turbomachinery

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Effect of heat treatment on the mechanical and biocorrosion behaviour of two Mg-Zn-Ca alloys

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journal of Magnesium and Alloys 2022年第2期10卷 581-595页

作者： N.Pulido-González P.hidalgo-Manrique S.García-Rodríguez B.Torres j.Rams Departamento de Matemática Aplicada Ciencia e Ingeniería de Materiales y Tecnología ElectrónicaESCETUniversidad Rey Juan CarlosC/Tulipán s/nMóstolesMadrid28933Spain

The effect of heat treatment on the mechanical and biocorrosion behaviour of the Mg-1 wt.%Zn-1 wt.%Ca(ZX11)and Mg-3 wt.%Zn-0.4 wt.%Ca(ZX30)alloys was *** this purpose,three-point bending tests as well as electrochemical and immersion tests in Hank’s solution were performed on both alloys in four different thermal conditions:as-cast,solution-treated,peak-aged and *** examinations revealed that the as-cast ZX11 and ZX30 alloys exhibit a microstructure composed ofα-Mg grains separated by large Mg_(2)Ca and Ca_(2)Mg_(6)Zn_(3) particles and by large Ca_(2)Mg_(6)Zn_(3) particles,*** solution treatment,the Ca_(2)Mg_(6)Zn_(3) precipitates at the grain boundaries(GBs)are fully dissolved in the ZX11 alloy,but mainly redistributed to form a more connected configuration in the ZX30 alloy,showing a poor age-hardening ***,after solution-treatment,galvanic corrosion and corrosion rate decreases in the former,but increases in the *** peak-aged condition displays the highest corrosion rate for both alloys,maybe due to an excessive number density of fine Ca_(2)Mg_(6)Zn_(3) particles acting as cathodic ***,the over-aged condition shows the lowest corrosion rate for the ZX11 alloy and a very similar one to that of the as-cast sample for the ZX30 *** ZX11 alloy shows generally better biocorrosion behaviour than the ZX30 alloy to its lower content in the Ca_(2)Mg_(6)Zn_(3) phase and thus reduced galvanic *** Mg_(2)Ca phase present in the studied ZX11 alloy has been proved to exhibit an increased corrosion potential,which has been related to an observed enrichment with Zn.

关键词： Magnesium alloys Biodegradable implants Heat treatment Microstructure Mechanical properties Corrosion

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Analysis of the anelastic deformation of high-entropy Pd_(20)Pt_(20)Cu_(20)Ni_(20)P_(20) metallic glass under stress relaxation and recovery

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journal of Materials Science & Technology 2022年第12期107卷 82-91页

作者： Y.j.Duan L.T.Zhang T.Wada H.Kato E.Pineda D.crespo j.M.Pelletier j.C.Qiao School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China Department of Physics Institute of Energy TechnologiesUniversitat Politècnica de CatalunyaBarcelona 08019Spain Institute for Materials Research Tohoku UniversitySendai 980-8577Japan Universitéde Lyon MATEISUMR CNRS5510Bat.B.PascalINSA-LyonF-69621 Villeurbanne CedexFrance

The anelastic deformation behavior of Pd_(20)Pt_(20)Cu_(20)Ni_(20)P_(20) high-entropy metallic glass was probed by monitoring the stress relaxation and recovery processes. The stress relaxation under consecutive strain steps can be described by the Kohlrausch-Williams-Watts(KWW) function. In addition, considering a hierarchy of relaxation processes related to the structural heterogeneity, a constitutive model is proposed in order to describe the whole process of stress relaxation and determine the contribution of different time scales. Moreover, a crossover from stochastic activation to percolation of flow defects with the ultimate strain can be observed during stress relaxation process. The anelastic recovery process after a strain step is studied as a function of the initial strain level and characterized by means of a direct spectrum analysis. The peaks in the recovery time-spectra revealed the evolution of flow defects in Pd_(20)Pt_(20)Cu_(20)Ni_(20)P_(20) high-entropy metallic glass. The understanding of the atomic free-volume zones effect and the anelastic deformation provides important insight into how atomic structural features affect the deformation behavior of high-entropy metallic glasses, and may provide a new avenue into the improvement of their mechanical properties.

关键词： High-entropy metallic glass Stress relaxation Anelastic deformation Flow defects Free-volume zones

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Gene therapy for spinal muscular atrophy:perspectives on the possibility of optimizing SMN1 delivery to correct all neurological and systemic perturbations

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Neural Regeneration Research 2025年第7期20卷 2011-2012页

作者： Sharon j.Brown Rafael j.Yáñez-Muñoz Heidi R.Fuller School of Pharmacy and Bioengineering Keele UniversityKeeleUK Wolfson Center for Inherited Neuromuscular Disease TORCH BuildingRJAH Orthopaedic HospitalOswestryUK *** Center of Gene and Cell TherapyDepartment of Biological SciencesSchool of Life Sciences and the EnvironmentRoyal Holloway University of LondonEghamUK

Spinal muscular atrophy(SMA)is a genetic condition that results in selective lower motor neuron loss with concomitant muscle weakness and *** genetic cause of SMA was understood in 1995 when loss or impairment of the survival motor neuron 1(SMN1)gene was identified as the main contributing factor(Lefebvre et al.,1995).This,in combination with the discovery that humans have a“back-up”gene,SMN2,which can produce low levels(approximately 10%)of the full-length functional SMN protein,has led to the generation of SMA-specific gene *** was traditionally classified according to age of symptom onset and developmental milestones achieved,with life expectancy and severity varying between ***,SMN2 copy number is used as a proxy for the prediction of disease severity,with higher SMN2 copy number typically being associated with reduced severity of SMA,although this relationship is not absolute:some individuals with low SMN2 copy number have less severe SMA phenotypes and vice ***,the etiology of SMA is further complicated by other factors,such as non-typical nucleotide variants and SMN2-independent modifiers of disease severity.

关键词： atrophy traditionally absolute

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Dynamic mechanical relaxation behavior of Zr_(35)Hf_(17.5)Ti_(5.5)Al_(12.5)Co_(7.5)Ni_(12)Cu_(10)high entropy bulk metallic glass

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journal of Materials Science & Technology 2021年第24期83卷 248-255页

作者： L.T.Zhang Y.j.Duan T.Wada H.Kato j.M.Pelletier D.crespo E.Pineda j.C.Qiao School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China Institute for Materials Research Tohoku UniversitySendai980-8577Japan Universitéde Lyon MATEISUMR CNRS5510Bat.B.PascalINSA-LyonF-69621Villeurbanne CedexFrance Department of Physics Barcelona Research Center in Multiscale Science and TechnologyInstitute of Energy TechnologiesUniversitat Politècnica de Catalunya08019BarcelonaSpain

Non-equiatomic high entropy bulk metallic glasses were reported recently and show unique mechanical and physical *** mechanical relaxation behavior of Zr_(35)Hf_(17.5)Ti_(5.5)Al_(12.5)Co_(7.5)Ni_(12)Cu_(10)high entropy bulk metallic glass was investigated by dynamic mechanical analysis(DMA)and the mechanical spectra could be well described by the quasi-point defects(QPD)*** to typical metallic glasses,the intensity of theβrelaxation of Zr_(35)Hf_(17.5)Ti_(5.5)Al_(12.5)Co_(7.5)Ni_(12)Cu_(10)high entropy bulk metallic glass is lower due to the sluggish *** the same time,the correlation factor is higher than that of conventional metallic glasses and this is ascribed to the high configuration *** parallel,physical aging below the glass transition temperature leads to a decrease of atomic mobility,caused by a decrease of the concentration of defects.

关键词： High entropy bulk metallic glass Mechanical relaxation Quasi-point defects Physical aging

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Molecular engineering binuclear copper catalysts for selective CO_(2) reduction to C_(2) products

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journal of Energy Chemistry 2024年第6期93卷 166-173,I0005页

作者： Qi Zhao Kai Lei Bao Yu Xia Rachel crespo-Otero Devis Di Tommaso Department of Chemistry School of Physical and Chemical SciencesQueen Mary University of LondonLondonE14NSUK Key Laboratory of Material Chemistry for Energy Conversion and Storage(Ministry of Education) Hubei Key Laboratory of Material Chemistry and Service FailureState Key Laboratory of Materials Processing and Die&Mould TechnologySchool of Chemistry and Chemical EngineeringHuazhong University of Science and Technology(HUST)Wuhan 430074HubeiChina Department of Chemistry University College LondonLondonWC1H 0AJUK Digital Environment Research Institute Queen Mary University of LondonEmpire HouseLondon E11HHUK

Molecular copper catalysts serve as exemplary models for correlating the structure-reaction-mechanism relationship in the electrochemical CO_(2) reduction(eCO_(2)R),owing to their adaptable environments surrounding the copper metal *** investigation,employing density functional theory calculations,focuses on a novel family of binuclear Cu molecular *** modulation of their coordination configuration through the introduction of organic groups aims to assess their efficacy in converting CO_(2) to C_(2)*** findings highlight the crucial role of chemical valence state in shaping the characteristics of binuclear Cu catalysts,consequently influencing the eCO_(2)R behaviour,Notably,the Cu(Ⅱ)Cu(Ⅱ)macrocycle catalyst exhibits enhanced suppression of the hydrogen evolution reaction(HER),facilitating proton trans fer and the eCO_(2)R *** rthermore,we explo re the impact of diverse electro n-withdrawing and electron-donating groups coordinated to the macrocycle(R=-F,-H,and-OCH_3)on the electron distribution in the molecular *** placement of-OCH_3 groups in the macrocycles leads to a favourable oxidation state of the Cu centres and subsequent C-C coupling to form C_(2) *** research provides fundamental insights into the design and optimization of binuclear Cu molecular catalysts for the electrochemical conversion of CO_(2) to value-added C_(2) products.

关键词： Molecular catalyst design Selective CO_(2)reduction C_(2)products Density functional theory calculations

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