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798 results on '"Cloetens, Peter"'

1. Single-distance nano-holotomography with coded apertures

Author

Nikitin, Viktor, Carlsson, Marcus, Mokso, Rajmund, Cloetens, Peter, and Gursoy, Doga

Subjects
Physics - Optics
Abstract

High-resolution phase-contrast 3D imaging using nano-holotomography typically requires collecting multiple tomograms at varying sample-to-detector distances, usually 3 to 4. This multi-distance approach significantly limits temporal resolution, making it impractical for operando studies. Moreover, shifting the sample complicates reconstruction, requiring precise alignment and interpolation to correct for shift-dependent magnification on the detector. In response, we propose and validate through simulations a novel single-distance approach that leverages coded apertures to structure beam illumination while the sample rotates. This approach is made possible by our proposed joint reconstruction scheme, which integrates coded phase retrieval with 3D tomography. This scheme ensures data consistency and achieves artifact-free reconstructions from a single distance.

Published
2024

2. X-ray nano-holotomography reconstruction with simultaneous probe retrieval

Author

Nikitin, Viktor, Carlsson, Marcus, Gursoy, Doga, Mokso, Rajmund, and Cloetens, Peter

Subjects
Electrical Engineering and Systems Science - Image and Video Processing, Physics - Optics
Abstract

In conventional tomographic reconstruction, the pre-processing step includes flat-field correction, where each sample projection on the detector is divided by a reference image taken without the sample. When using coherent X-rays as probe, this approach overlooks the phase component of the illumination field (probe), leading to artifacts in phase-retrieved projection images, which are then propagated to the reconstructed 3D sample representation. The problem intensifies in nano-holotomography with focusing optics, that due to various imperfections create high-frequency components in the probe function. Here, we present a new iterative reconstruction scheme for holotomography, simultaneously retrieving the complex-valued probe function. Implemented on GPUs, this algorithm results in 3D reconstruction resolving twice thinner layers in a 3D ALD standard sample measured using nano-holotomography.

Published
2024

6. A hierarchical approach for modelling X-ray beamlines. Application to a coherent beamline

Author

del Rio, Manuel Sanchez, Celestre, Rafael, Glass, Mark, Pirro, Giovanni, Reyes-Herrera, Juan, Barrett, Ray, da Silva, Julio Cesar, Cloetens, Peter, Shi, Xianbo, and Rebuffi, Luca

Subjects
Physics - Optics, Physics - Instrumentation and Detectors
Abstract

We consider different approaches to simulate a modern X-ray beamline. Several methodologies with increasing complexity are applied to discuss the relevant parameters that quantify the beamline performance. Parameters such as flux, dimensions and intensity distribution of the focused beam and coherence properties are obtained from simple analytical calculations to sophisticated computer simulations using ray-tracing and wave optics techniques. A latest-generation X-ray nanofocusing beamline for coherent applications (ID16A at the ESRF) has been chosen to study in detail the issues related to highly demagnifying synchrotron sources and exploiting the beam coherence. The performance of the beamline is studied for two storage rings: the old ESRF-1 (emittance 4000~pm) and the new ESRF-EBS (emittance 150~pm). In addition to traditional results in terms of flux and beam sizes, an innovative study on the partial coherence properties based on the propagation of coherent modes is presented. The different algorithms and methodologies are implemented in the software suite OASYS. Those are discussed with emphasis placed upon the their benefits and limitations of each.

Published
2019
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7. Uncovering nitroxoline activity spectrum, mode of action and resistance across Gram-negative bacteria

Author

Cacace, Elisabetta, primary, Tietgen, Manuela, additional, Steinhauer, Meike, additional, Mateus, André, additional, Schultze, Tilman G., additional, Eckermann, Marina, additional, Galardini, Marco, additional, Varik, Vallo, additional, Koumoutsi, Alexandra, additional, Parzeller, Jordan J., additional, Corona, Federico, additional, Orakov, Askarbek, additional, Knopp, Michael, additional, Brauer-Nikonow, Amber, additional, Bork, Peer, additional, Romao, Celia V., additional, Zimmermann, Michael, additional, Cloetens, Peter, additional, Savitski, Mikhail M., additional, Typas, Athanasios, additional, and Göttig, Stephan, additional

Published
2024
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9. Crumpling of silver nanowires by endolysosomes strongly reduces toxicity

Author

Lehmann, Sylvia G, Toybou, Djadidi, del Real, Ana-Elena Pradas, Arndt, Devrah, Tagmount, Abderrahmane, Viau, Muriel, Safi, Malak, Pacureanu, Alexandra, Cloetens, Peter, Bohic, Sylvain, Salomé, Murielle, Castillo-Michel, Hiram, Omaña-Sanz, Brenda, Hofmann, Annette, Vulpe, Christopher, Simonato, Jean-Pierre, Celle, Caroline, Charlet, Laurent, and Gilbert, Benjamin

Subjects
Animals, Cell Line, Cells, Cultured, Electric Conductivity, Endosomes, Fibroblasts, Fishes, Humans, Lysosomes, Mice, Nanowires, Oxidative Stress, Silver, nanotechnology, endocytosis, fiber toxicity
Abstract

Fibrous particles interact with cells and organisms in complex ways that can lead to cellular dysfunction, cell death, inflammation, and disease. The development of conductive transparent networks (CTNs) composed of metallic silver nanowires (AgNWs) for flexible touchscreen displays raises new possibilities for the intimate contact between novel fibers and human skin. Here, we report that a material property, nanowire-bending stiffness that is a function of diameter, controls the cytotoxicity of AgNWs to nonimmune cells from humans, mice, and fish without deterioration of critical CTN performance parameters: electrical conductivity and optical transparency. Both 30- and 90-nm-diameter AgNWs are readily internalized by cells, but thinner NWs are mechanically crumpled by the forces imposed during or after endocytosis, while thicker nanowires puncture the enclosing membrane and release silver ions and lysosomal contents to the cytoplasm, thereby initiating oxidative stress. This finding extends the fiber pathology paradigm and will enable the manufacture of safer products incorporating AgNWs.

Published
2019

15. Quantifying Electrochemical Degradation in Single-crystalline LiNi0.8Mn0.1Co0.1O2–Graphite pouch cells through Operando X-ray and Post-mortem Investigations

Author

S. Menon, Ashok, primary, Shah, Nickil, additional, A. Gott, James, additional, Fiamegkou, Eleni, additional, J. W. Ogley, Matthew, additional, J. Paez Fajardo, Galo, additional, Vaenas, Naoum, additional, Ellis, Ieuan, additional, Ravichandran, Nishitha, additional, Cloetens, Peter, additional, Karpov, Dmitry, additional, Warnett, Jay, additional, Malliband, Paul, additional, Walker, David, additional, West, Geoff, additional, Loveridge, Melanie, additional, and Piper, Louis, additional

Published
2023
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16. Intracellular Fate of Sub-Toxic Concentration of Functionalized Selenium Nanoparticles in Aggressive Prostate Cancer Cells

Author

Bissardon, Caroline, primary, Proux, Olivier, additional, Gazze, Salvatore Andrea, additional, Filhol, Odile, additional, Toubhans, Benoît, additional, Sauzéat, Lucie, additional, Bouchet, Sylvain, additional, Lewis, Aled R., additional, Maffeis, Thierry, additional, Hazemann, Jean-Louis, additional, Bayat, Sam, additional, Cloetens, Peter, additional, Conlan, R. Steven, additional, Charlet, Laurent, additional, and Bohic, Sylvain, additional

Published
2023
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21. Improved light extraction in the bioluminescent lantern of a Photuris firefly (Lampyridae)

Author

Bay, Annick, Cloetens, Peter, Suhonen, Heikki, and Vigneron, Jean Pol

Subjects
Physics - Optics, Physics - Biological Physics
Abstract

A common problem of light sources emitting from an homogeneous high-refractive index medium into air is the loss of photons by total internal reflection. Bioluminescent organisms, as well as artificial devices, have to face this problem. It is expected that life, with its mechanisms for evolution, would have selected appropriate optical structures to get around this problem, at least partially. The morphology of the lantern of a specific firefly in the genus Photuris has been examined. The optical properties of the different parts of this lantern have been modeled, in order to determine their positive or adverse effect with regard to the global light extraction. We conclude that the most efficient pieces of the lantern structure are the misfit of the external scales (which produce abrupt roughness in air) and the lowering of the refractive index at the level of the cluster of photocytes, where the bioluminescent production takes place., Comment: 13 pages, 11 figures, published in Optics Express

Published
2012
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24. Revealing the degradation pathways of layered Li-rich oxide cathodes

Author

He, Xin, primary, Liu, Zhimeng, additional, Zeng, Yuqiang, additional, Tan, Junyang, additional, Wang, Hailong, additional, Zhu, Yudong, additional, Geng, Xin, additional, Guttmann, Peter, additional, Hou, Xu, additional, Yang, Yang, additional, Xu, Yunkai, additional, Cloetens, Peter, additional, Wei, Yinping, additional, Lu, Jun, additional, Li, Jie, additional, Liu, Bilu, additional, Winter, Martin, additional, Kostecki, Robert, additional, and Lin, Yuanjing, additional

Published
2023
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25. Experimental growth law for bubbles in a 'wet' 3D liquid foam

Author

Lambert, Jérôme, Mokso, Rajmund, Cantat, Isabelle, Cloetens, Peter, Delannay, Renaud, Glazier, James A., and Graner, François

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

We used X-ray tomography to characterize the geometry of all bubbles in a liquid foam of average liquid fraction $\phi_l\approx 17 %$ and to follow their evolution, measuring the normalized growth rate $\mathcal{G}=V^{-{1/3}}\frac{dV} {dt}$ for 7000 bubbles. While $\mathcal{G}$ does not depend only on the number of faces of a bubble, its average over $f-$faced bubbles scales as $G_f\sim f-f_0$ for large $f$s at all times. We discuss the dispersion of $\mathcal{G}$ and the influence of $V$ on $\mathcal{G}$., Comment: 10 pages, submitted to PRL

Published
2007
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30. Correlating STED and synchrotron XRF nano-imaging to explore metal functions in synapses.

Author

Domart, Florelle, Cloetens, Peter, Roudeau, Stéphane, Carmona, Asuncion, Verdier, Emeline, Choquet, Daniel, and Ortega, Richard

Subjects
*TRACE metals, *COPPER, *SYNCHROTRON radiation, *SYNCHROTRONS, *CELL imaging, *DENDRITIC spines
Abstract

Zinc and copper are involved in neuronal differentiation and synaptic plasticity but the molecular mechanisms behind these processes are still elusive due in part to the difficulty of imaging trace metals together with proteins at the synaptic level. We correlate stimulated-emission-depletion microscopy (STED) of proteins and synchrotron X-ray fluorescence (XRF) imaging of trace metals, both performed with 40 nm spatial resolution, on primary rat hippocampal neurons. Synchrotron XRF was performed on the ID16A Nano-Imaging beamline at the European Synchrotron Radiation Facility. ID16A beamline provides a pink nanoprobe (ΔE/E≈1%) at two discrete energies: E = 17kev and 33.6 kev. For the correlative STED-SXRF experiments 17 keV was chosen, despite a larger focus at lower energy, as it is more efficient in exciting the XRF of the biologically relevant elements zinc and copper. The X-ray focus with dimensions of 35 nm (H) x 57 nm (V) provided a flux of 3.7 1011 ph/s. Thanks to this experimental setup, we reveal the co-localization at the nanoscale of zinc and tubulin in dendrites with a molecular ratio of about one zinc atom per tubulin-αβ dimer. We observe the co-segregation of copper and F-actin within the nano-architecture of dendritic protrusions. These results indicate new functions for zinc and copper in the modulation of the synaptic cytoskeleton morphology, a mechanism associated to structural plasticity. From a methodological perspective, the combination of STED super-resolution microscopy and nano-SXRF imaging stands as a solid new tool for the identification of metalloproteins directly in cells by correlating cellular imaging methods at a supramolecular scale. [ABSTRACT FROM AUTHOR]

Published
2023
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32. Quantifying electrochemical degradation in single-crystalline LiNi0.8Mn0.1Co0.1O2–graphite pouch cells through operando X-ray and post-mortem investigations

Author

Menon, Ashok S., Shah, Nickil, Gott, James A., Fiamegkou, Eleni, Ogley, Matthew J. W., Paez Fajardo, Galo J., Vaenas, Naoum, Ellis, Ieuan, Ravichandran, Nishitha, Cloetens, Peter, Karpov, Dmitry, Warnett, Jay, Malliband, Paul, Walker, David, West, Geoffrey D., Loveridge, Melanie, Piper, Louis F. J., Menon, Ashok S., Shah, Nickil, Gott, James A., Fiamegkou, Eleni, Ogley, Matthew J. W., Paez Fajardo, Galo J., Vaenas, Naoum, Ellis, Ieuan, Ravichandran, Nishitha, Cloetens, Peter, Karpov, Dmitry, Warnett, Jay, Malliband, Paul, Walker, David, West, Geoffrey D., Loveridge, Melanie, and Piper, Louis F. J.

Abstract

Layered nickel-rich lithium transition metal oxides (LiNixMnyCo1−x−yO2; where x ≥ 0.8), with single-crystalline morphology, are promising future high-energy-density Li-ion battery cathodes due to their ability to mitigate particle-cracking-induced degradation. This is due to the absence of grain boundaries in these materials, which prevents the build-up of bulk crystallographic strain during electrochemical cycling. Compared to their polycrystalline counterparts, there is a need to study single-crystalline Ni-rich cathodes using operando X-ray methods in uncompromised machine-manufactured industry-like full cells to understand their bulk degradation mechanisms as a function of different electrochemical cycling protocols. This can help us identify factors to improve their long-term performance. Here, through in-house operando X-ray studies of pilot-line-built LiNi0.8Mn0.1Co0.1O2–Graphite A7 pouch cells, it is shown that their electrochemical capacity fade under harsh conditions (2.5–4.4 V and 40 °C for 100 cycles at C/3 rate) primarily stems from the high-voltage reconstruction of the cathode surface from a layered to a cubic (rock salt) phase that impedes Li+ kinetics and increases cell impedance. Post-mortem electron and X-ray microscopy show that these cathodes can withstand severe anisotropic structural changes and show no cracking when cycled under such conditions. Comparing these results to those from commercial Li-ion cells with surface-modified single-crystalline Ni-rich cathodes, it is identified that cathode surface passivation can mitigate this type of degradation and prolong cycle life. In addition to furthering our understanding of degradation in single-crystalline Ni-rich cathodes, this work also accentuates the need for practically relevant and reproducible fundamental investigations of Li-ion cells and presents a methodology for achieving this.

Published
2023

39. 3D flexible nanostructured thermoelectric devices grown by scalable techniques

Author

Caballero-Calero, Olga, Cerviño Solana, Pablo, Rodríguez-Martín, Álvaro, Uricochea, Natalia, Ramírez-Peral, María Jesús, Alcalá, Germán, Monaco, Federico, Cloetens, Peter, and Martín-González, Marisol

Abstract

Resumen del trabajo presentado en la 18th European Conference on Thermoelectrics , celebrada en Barcelona (España), del 14 al 18 de septiembre de 2022, In order to reduce the complexity of developing nanostructured thermoelectric materials, and thus, obtain enhanced properties for applications, we report the template-assisted electrochemical deposition of bismuth telluride inside commercial membranes. The objective is to develop efficient, cost-effective, flexible and wearable thermoelectric generators (TEGs) by the use of low cost and scalable fabrication techniques along with a reduction in the amount of material used when compared to thin films. The use of different nanoporous membranes gives rise to different nanostructured morphologies, given that the electrochemical process produces a replica of the initial porous structure. Here we will fabricate thermoelectric 3D nanostructures inside flexible templates (made of polyester and cellulose) by electrochemical deposition as it has been previously done inside alumina templates [A. Ruiz-Clavijo., O. Caballero-Calero, M. Martín-González, Nanomaterials, 8 (2018) 345]. The morphology has been studied with SEM and Tomography, the crystalline orientation with XRD, the composition with EDX, and also Raman spectroscopy has been used to characterize the structures. Then, different transport measurements have been carried on. In fact, a certain increase is expected, as it was proved in [A. Ruiz-Clavijo., O. Caballero-Calero, C. V. Manzano, X. Maeder, A. Beardo, X. Cartoixa¿, X. Álvarez, M. Martín-González, ACS Applied Energy Materials, 4 (2021). 13556-13566] for 3D interconnected nanowire networks of bismuth telluride inside alumina. In that paper we showed the importance of increasing surface to volume ratio, as well as the relevance of nano-features in the structure, in order to improve the efficiency. In this case, the nanostructure is not as ordered as 3D nanowire network, but similar features are present, and they should have an impact in the final efficiency. Finally, further metallic contacts made of electrodeposited gold and/or nickel will be also fabricated in order to improve their electrical contacts and test such nanostructures as thermoelectric generators.

Published
2022

41. Evidence for interstellar origin of seven dust particles collected by the Stardust spacecraft

Author

Westphal, Andrew J., Stroud, Rhonda M., Bechtel, Hans A., Brenker, Frank E., Butterworth, Anna L., Flynn, George J., Frank, David R., Gainsforth, Zack, Hillier, Jon K., Postberg, Frank, Simionovici, Alexandre S., Sterken, Veerle J., Nittler, Larry R., Allen, Carlton, Anderson, David, Ansari, Asna, Bajt, Saša, Bastien, Ron K., Bassim, Nabil, Bridges, John, Brownlee, Donald E., Burchell, Mark, Burghammer, Manfred, Changela, Hitesh, Cloetens, Peter, Davis, Andrew M., Doll, Ryan, Floss, Christine, Grün, Eberhard, Heck, Philipp R., Hoppe, Peter, Hudson, Bruce, Huth, Joachim, Kearsley, Anton, King, Ashley J., Lai, Barry, Leitner, Jan, Lemelle, Laurence, Leonard, Ariel, Leroux, Hugues, Lettieri, Robert, Marchant, William, Ogliore, Ryan, Ong, Wei Jia, Price, Mark C., Sandford, Scott A., Tresseras, Juan-Angel Sans, Schmitz, Sylvia, Schoonjans, Tom, Schreiber, Kate, Silversmit, Geert, Solé, Vicente A., Srama, Ralf, Stadermann, Frank, Stephan, Thomas, Stodolna, Julien, Sutton, Stephen, Trieloff, Mario, Tsou, Peter, Tyliszczak, Tolek, Vekemans, Bart, Vincze, Laszlo, Von Korff, Joshua, Wordsworth, Naomi, Zevin, Daniel, and Zolensky, Michael E.

Published
2014

46. Nanostructured bismuth telluride electrochemically grown inside flexible templates

Author

Caballero-Calero, Olga, Cerviño Solana, Pablo, Rodríguez-Martín, Álvaro, Uricochea, Natalia, Ramírez-Peral, María Jesús, Alcalá, Germán, Monaco, Federico, Cloetens, Peter, and Martín-González, Marisol

Abstract

Trabajo presentado en NanoSpain2022, celebrado en Madrid (España), del 17 al 20 de mayo de 2022, In this work, we present different nano-structures of bismuth telluride based on scalable and low cost fabrication techniques. The objective is to improve the thermoelectric performance of this material grown by electrochemical deposition, and then use these nanostructures to develop efficient flexible thermoelectric generators (TEGs) which will allow the conversion of wasted heat around room temperature into usable electrical energy. The main advantage of nanostructures over thin films or bulk is that they should increase the thermoelectric performance of the bismuth telluride (which is the most used thermoelectric material for room temperature appilcations) by lowering its thermal conductivity. This has been already proved for 3D interconnected nanowire networks of bismuth telluride [1]. In that work, we showed that both the increasing of the surface to volume ratio and the influence of the nanostructure in the the phonon scattering phenomena are the main responsibles of the improvement, but the templates used in that case were made of non-flexible alumina. Here, we will use two different flexible commercial templates to obtain nanostructured thermoelectric materials by template-assisted electrochemical deposition of bismuth telluride: polyester membranes (obtaining an intrincate 3D nanostructure) and cellulose membranes (obtaining a highly porous structure). As it was previously done with the growth of bismuth telluride inside alumina templates [2], the nanostructured bismuth telluride grown inside the flexible templates will be then characterized to optimize the fabricartion parameters to obtain highly oriented, stoichiometric material in such nanostructures.

Published
2022

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