Quantitative interior x-ray nanotomography by a hybrid imaging technique

Hierarchical structures appear often in life and materials sciences, and their characterization profits greatly from imaging methods that allow seamless probing of various length scales without sacrificing image quality. X-ray tomography is particularly adept at probing 3D structures; however, zooming in on a region of interest results in a loss of quantitativeness of image contrast and suffers from artifacts unless a priori knowledge or assumptions about the sample are used. Here, we demonstrate a hybrid technique that exploits a micrometer-resolution overview to realize ab initio nanoscale interior tomography with quantitative contrast. In a study of avian eggshell, a model for bionanoporous materials, our approach reveals a complex arrangement of vesicles with sizes ranging from hundred nanometers to a few micrometers. We anticipate that such an approach can be widely adopted and benefited from at synchrotron and laboratory sources, for instance, where such zooming capabilities are already present or can be readily realized

Viability of coaxial atomization for disintegration of cell solutions in cell spray applications

[EN] Treating Leukemia with intravenous stem cell transplantation represents a well-established therapy technique. For applications, that require high local cell concentrations, transplantation by conventional intravenous injection is less potent, due to cell distribution with blood circulation. Instead, spraying them directly onto the injured or diseased area shows promising results in various applications, e.g. superficial treatment of topographically challenging wounds, in situ seeding of cells on implants, deposition of cells in tubular organs for stem cell therapy. The present work aims for a basic knowledge about viability boundaries for coaxial cell-spray atomization and the reciprocal influence between cells in solution and primary breakup mechanics. A generic modular nozzle is developed, to ensures reproducible boundary conditions. Investigations are conducted regarding primary breakup and relations between resulting droplet size distribution and cell survival. Measurements are performed, utilizing microscopic high-speed visualization with suitable image post processing. Cell viability is analyzed using phase contrast microscopy prior and after atomization. A relation between Rayleigh-Taylor instability wavelength and droplet size distributions by means of Sauter mean diameter (SMD) and cell survival rate (CSR) is suggested. A power law is presented, exclusively dependent on dimensionless measures (λ⊥ ∼ Re−1/2We−1/3 ) which is found to be proportional to SMD and CSR.We gratefully acknowledge financial support from the Excellence Initiative of the German federal state governments (Exploratory Research Space, RWTH Aachen University).Bieber, M.; Menzel, S.; Thiebes, A.; Cornelissen, C.; Jockenhoevel, S.; Kneer, R.; Reddemann, M. (2017). Viability of coaxial atomization for disintegration of cell solutions in cell spray applications. En Ilass Europe. 28th european conference on Liquid Atomization and Spray Systems. Editorial Universitat Politècnica de València. 521-528. https://doi.org/10.4995/ILASS2017.2017.4609OCS52152

Chromium Isotope Behavior During Serpentinite Dehydration in Oceanic Subduction Zones

Fluids released through the dehydration of serpentinite can be rich in Cl −, which enables the significant mobility of Cr in subduction zones. However, the Cr isotope behavior accompanying the mobility of Cr during serpentinite dehydration is still poorly constrained. Here, we report high-precision Cr isotope data for a unique suite of serpentinites that represent metamorphic products at different depths in oceanic subduction zones. Low-grade serpentinites affected by significant Cr loss during serpentinization exhibit remarkably higher δ 53Cr, while samples with Cr contents >∼1,800 ppm typically preserve mantle-like δ 53Cr. Antigorite serpentinites have an average δ 53Cr value of −0.17‰ ± 0.19‰ (n = 12, 2SD), which is statistically lower than those of low-grade serpentinite (−0.05‰ ± 0.30‰, n = 80, 2SD) and higher-grade chlorite harzburgite (−0.10‰ ± 0.27‰, n = 22, 2SD). This suggests that resolvable Cr isotope fractionation occurs during serpentinite dehydration, which is explained by the variability of Cr isotope behavior in the presence of Cl-bearing fluids at different dehydration stages. No obvious Cr isotope fractionation was found during chlorite harzburgite dehydration, probably related to the limited Cr mobility in a Cl-poor fluid. Other processes, such as melt extraction, external fluid influx and retrograde metamorphism, have negligible effects on the Cr isotope systematics of meta-serpentinites. Fluids released by serpentinite dehydration may have a great effect on the Cr isotope heterogeneity of mantle wedge peridotites and arc magmas.National Key Ramp;D Program of ChinaStrategic Priority Research Program (B) of CAS 2018YFA0702600National Natural Science Foundation of China (NSFC) XDB41000000Fundamental Research Funds for the Central Universities 42073029 41973004CNSAMICIN/AEI D020204FEDER program "Una manera de hacer Europa" PID2022-136471N-B-C21 C22 PID2019-111715GB-I00AEIFSE program "FSE invierte en tu futuro" RYC2018-024363-IJunta de AndaluciaEuropean Union (EU) Postdoc_21_00791European Social Fund (ESF)Junta de Andalucia RNM-131 RNM-37

5G New Radio for Terrestrial Broadcast: A Forward-Looking Approach for NR-MBMS

"© 2019 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] 3GPP LTE eMBMS release (Rel-) 14, also referred to as further evolved multimedia broadcast multicast service (FeMBMS) or enhanced TV (EnTV), is the first mobile broadband technology standard to incorporate a transmission mode designed to deliver terrestrial broadcast services from conventional high power high tower (HPHT) broadcast infrastructure. With respect to the physical layer, the main improvements in FeMBMS are the support of larger inter-site distance for single frequency networks (SFNs) and the ability to allocate 100% of a carrier's resources to the broadcast payload, with self-contained signaling in the downlink. From the system architecture perspective, a receive-only mode enables free-to-air (FTA) reception with no need for an uplink or SIM card, thus receiving content without user equipment registration with a network. These functionalities are only available in the LTE advanced pro specifications as 5G new radio (NR), standardized in 3GPP from Rel-15, has so far focused entirely on unicast. This paper outlines a physical layer design for NR-MBMS, a system derived, with minor modifications, from the 5G-NR specifications, and suitable for the transmission of linear TV and radio services in either single-cell or SFN operation. This paper evaluates the NR-MBMS proposition and compares it to LTE-based FeMBMS in terms of flexibility, performance, capacity, and coverage.This work was supported in part by the European Commission through the 5G-PPP Project 5G-Xcast (H2020-ICT-2016-2 call) under Grant 761498.Gimenez, JJ.; Carcel, JL.; Fuentes, M.; Garro, E.; Elliott, S.; Vargas, D.; Menzel, C.... (2019). 5G New Radio for Terrestrial Broadcast: A Forward-Looking Approach for NR-MBMS. IEEE Transactions on Broadcasting. 65(2):356-368. https://doi.org/10.1109/TBC.2019.291211735636865

Mantle wedge oxidation due to sediment-infiltrated deserpentinisation

This work is part of the project DESTINE (PID2019-105192GB-I00) funded by MICIN/AEI/10.13039/501100011033 and the FEDER program “una manera de hacer Europa”. J.A.P.N. acknowledges a Ramón y Cajal contract (RYC2018-024363-I) funded by MICIN/AEI/10.13039/501100011033 and the FSE program “FSE invierte en tu futuro”. This research is part of the Junta de Andalucia research group RNM-131.The Earth's mantle is oxygen-breathing through the sink of oxidised tectonic plates at convergent Margins. Ocean floor serpentinisation increases the bulk oxidation state of iron relative to dry oceanic mantle and results in a variable intake of other redox-sensitive elements such as sulphur. The reversibility of seafloor oxidation in subduction zones during high-pressure dehydration of serpentinite (“deserpentinisation”) at subarc depths and the capacity of the resulting fluids to oxidise the mantle source of arc basalts are highly contested. Thermodynamic modelling, experiments, and metaperidotite study in exhumed highpressure terrains result in differing estimates of the redox state of deserpentinisation fluids, ranging from low to highly oxidant. Here we show that although intrinsic deserpentinisation fluids are highly oxidant, the infiltration of small fractions of external fluids equilibrated with metasedimentary rocks strongly modulates their redox state and oxidation-reduction capacity explaining the observed discrepancies in their redox state. Infiltration of fluids equilibrated with graphite-bearing sediments reduces the oxidant, intrinsic deserpentinisation fluids to oxygen fugacities similar to those observed in most graphite-furnace experiments and natural metaperidotites. However, infiltration of CO2-bearing fluids equilibrated with modern GLOSS generates sulphate-rich, highly oxidising deserpentinisation fluids. We show that such GLOSS infiltrated deserpentinisation fluids can effectively oxidise the mantle wedge of cold to hot subduction zones potentially accounting for the presumed oxidised nature of the source of arc basalts.MICIN/AEI/10.13039/501100011033 (PID2019-105192GB-I00) (RYC2018-024363-I)FEDERFSEJunta de Andalucia research group RNM-131

Optical metamaterials with quasicrystalline symmetry: Symmetry-induced optical isotropy

We apply the concept of quasicrystals to metamaterials and experimentally demonstrate metasurfaces with isotropic properties and high resonance strength. By comparing quasicrystalline, periodic, and amorphous metasurfaces we quantify the impact of symmet

Quasicrystal metamaterials: A route to optical isotropy

We introduce a novel class of metamaterials with quasicrystalline meta-atom arrangements and study their properties in comparison with periodic and disordered metamaterials. We show that quasicrystalline metamaterials exhibit isotropic optical propertie