TY - JOUR A1 - Lopez-Serrano Oliver, Ana A1 - Haase, A. A1 - Peddinghaus, A. A1 - Wittke, D. A1 - Jakubowski, Norbert A1 - Luch, A. A1 - Grützkau, A. A1 - Baumgart, S. T1 - Mass cytometry enabling absolute and fast quantification of silver nanoparticle uptake at the single cell level N2 - In the last decades, significant efforts have been made to investigate possible cytotoxic effects of metallic nanoparticles (NPs). Methodologies enabling precise information regarding uptake and intracellular distribution of NPs at the single cell level remain to be established. Mass cytometry (MC) has been developed for high-dimensional single cell analyses and is a promising tool to quantify NP−cell interactions. Here, we aim to establish a new MC-based quantification procedure to receive absolute numbers of NPs per single cell by using a calibration that considers the specific transmission efficiency (TE) of suspended NPs. The current MC-quantification strategy accept TE values of complementary metal solutions. In this study, we demonstrate the different transmission behavior of 50 nm silver NPs (AgNP) and silver nitrate solution. We have used identical AgNPs for calibration as for in vitro-differentiated macrophages (THP-1 cell line) in a time- and dose-dependent manner. Our quantification relies on silver intensities measuring AgNPs in the same detection mode as the cells. Results were comparable with the TE quantification strategy using AgNPs but differed when using ionic silver. Furthermore, intact and digested cell aliquots were measured to investigate the impact of MC sample processing on the amount of AgNPs/cell. Taken together, we have provided a MC-specific calibration procedure to precisely calculate absolute numbers of NPs per single cell. Combined with its unique feature of multiplexing up to 50 parameters, MC provides much more information on the single cell level than single cell-inductively coupled plasma mass spectrometry (SC-ICP-MS) and, therefore, offers new opportunities in nanotoxicology. KW - ICP-MS KW - Nanoparticle KW - Cell KW - SC-ICP-MS KW - Mass cytometry PY - 2019 DO - https://doi.org/10.1021/acs.analchem.9b01870 SN - 0003-2700 SN - 1520-6882 VL - 91 IS - 18 SP - 11514 EP - 11519 PB - American Chemical Society (ACS Publications) CY - Washington AN - OPUS4-48986 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mielke, Johannes A1 - Dohányosová, P. A1 - Müller, P. A1 - Lopez, S. A1 - Hodoroaba, Vasile-Dan T1 - Electrospray as a sample preparation tool for electron microscopic investigations: Toward quantitative evaluation of nanoparticles N2 - The potential of electrospray deposition, for the controlled preparation of particles for imaging in electron microscopes, is evaluated on various materials: from mono-modal suspensions of spherical particles to multimodal suspensions and to real-world industrial materials. It is shown that agglomeration is reduced substantially on the sample carrier, compared with conventional sample preparation techniques. For the first time, it is possible to assess the number concentration of a tri-modal polystyrene suspension by electron microscopy, due to the high deposition efficiency of the electrospray. We discovered that some suspension stabilizing surfactants form artifact particles during electrospraying. These can be avoided by optimizing the sprayed suspension. KW - Electrospray deposition KW - Nanoparticles KW - SEM KW - TEM KW - Sample preparation PY - 2017 UR - https://www.cambridge.org/core/journals/microscopy-and-microanalysis/article/electrospray-as-a-sample-preparation-tool-for-electron-microscopic-investigations-toward-quantitative-evaluation-of-nanoparticles/483B212FF290B7EC001A212A19E4E72A DO - https://doi.org/10.1017/S1431927617010145 SN - 1435-8115 SN - 1431-9276 VL - 23 IS - S1 (July) SP - 1896 EP - 1897 PB - Cambridge University Press CY - New York, NY, U.S.A. AN - OPUS4-42453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guehrs, E. A1 - Schneider, M. A1 - Günther, Ch. M. A1 - Hessing, P. A1 - Heitz, K. A1 - Wittke, D. A1 - López-Serrano Oliver, Ana A1 - Jakubowski, Norbert A1 - Plendl, J. A1 - Eisebitt, S. A1 - Haase, A. T1 - Quantification of silver nanoparticle uptake and distribution within individual human macrophages by FIB/SEM slice and view N2 - Quantification of nanoparticle (NP) uptake in cells or tissues is very important for safety assessment. Often, electron microscopy based approaches are used for this purpose, which allow imaging at very high resolution. However, precise quantification of NP numbers in cells and tissues remains challenging. The aim of this study was to present a novel approach, that combines precise quantification of NPs in individual cells together with high resolution imaging of their intracellular distribution based on focused ion beam/ scanning electron microscopy (FIB/SEM) slice and view approaches. KW - Nanoparticles KW - FIB/SEM slice and view KW - Absolute dose KW - Cellular internalization KW - Macrophage PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-400626 DO - https://doi.org/10.1186/s12951-017-0255-8 SN - 1477-3155 VL - 15 SP - Article 21, 1 EP - 11 AN - OPUS4-40062 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Suárez Ocano, Patricia A1 - Agudo Jácome, Leonardo A1 - Lopez-Galilea, I. A1 - Darvishi Kamachali, Reza A1 - Fries, S. G. T1 - Data regarding the experimental findings compared with CALPHAD calculations of the AlMo0.5NbTa0.5TiZr refractory high entropy superalloy N2 - This contribution contains the raw data used to compare experimental results with thermodynamic calculations using the CALPHAD method, which is related to the research article “The AlMo0.5NbTa0.5TiZr refractory high entropy superalloy: experimental findings and comparison with calculations using the CALPHAD method” [1] , and therefore this article can be used as a basis for interpreting the data contained therein. The AlMo0.5NbTa0.5TiZr refractory superalloy was characterized in the cast and annealed condition (1400 °C for 24 h) in order to measure grain size and to identify and measure the size and area fraction of the phases present. The raw data of this article include X-ray diffraction (XRD) measurements, microstructural characterization by scanning and transmission electron microscopy (SEM and TEM), and elemental analysis by energy dispersive X-ray spectroscopy (EDX). XRD includes the determination of phases and the lattice parameters (A2, B2, and hexagonal structure). Microstructural analysis by scanning and transmission electron microscopy includes (1) identification of composition, size, and volume fraction of the present phases and (2) determination of grain size. Based on these experimental data, it is possible to identify similarities and discrepancies with the data calculated using the CALPHAD method for the alloy under study in Ref. [1] , which provides the basis for better and more efficient development of reliable databases. KW - Transmission electron microscopy KW - Scanning electron microscopy KW - Microstructural characterization KW - Refractory high entropy alloys PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568009 DO - https://doi.org/10.1016/j.dib.2022.108858 SN - 2352-3409 VL - 46 SP - 1 EP - 19 PB - Elsevier CY - Amsterdam AN - OPUS4-56800 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Suárez Ocano, Patricia A1 - Fries, S. G. A1 - Lopez-Galilea, I. A1 - Darvishi Kamachali, Reza A1 - Roik, J. A1 - Agudo Jácome, Leonardo T1 - The AlMo0.5NbTa0.5TiZr refractory high entropy superalloy: Experimental findings and comparison with calculations using the CALPHAD method N2 - Detailed microstructural characterization of the AlMo0.5NbTa0.5TiZr refractory high entropy superalloy in the as-cast state is reported for first time and compared with the state annealed at 1400 oC for 24 h. The former shows a dendritic structure, with a mixture of A2/B2 phases < 20 nm in both the dendritic and interdendritic regions. A mostly amorphous phase, rich in Al and Zr, is found within the interdendritic region. The annealed state reproduced the combination of A2/B2/Al-Zr-rich phases reported previously. Calculations from two relevant ThermoCalc databases were compared with the experimental results. Equilibrium calculations were compared with results for the annealed alloy, whereas solidification paths calculated using Scheil-Gulliver model were used for comparison with the as-cast alloy. A previously hypothesized spinodal decomposition during cooling as the mechanism responsible for the patterned A2/B2 microstructure is confirmed via the CALPHAD calculations, pointing to its use as an efficient design tool for such alloys. Finally, the comparison between the experimental and computational findings allowed better understanding the solidification path and equilibrium stability of this alloy, giving a base to make better decisions on the field of new refractory superalloy design. KW - CALPHAD database analysis KW - Refractory superalloys KW - Chemically complex alloy KW - Characterization KW - Microstructure PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545906 DO - https://doi.org/10.1016/j.matdes.2022.110593 SN - 1873-4197 VL - 217 SP - 1 EP - 13 PB - Elsevier CY - Amsterdam AN - OPUS4-54590 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Menzel, M. A1 - Scharf, O. A1 - Novak, S. A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Hischenhuber, P. A1 - Buzanich, Günter A1 - Meyer, A. A1 - Lopez, V. A1 - McIntosh, K. A1 - Streli, C. A1 - Havrilla, G. A1 - Fittschen, U. T1 - Shading in TXRF: calculations and experimental validation using a color X-ray camera N2 - Absorption effects in total reflection X-ray fluorescence (TXRF) analysis are important to consider, especially if external calibration is to be applied. With a color X-ray camera (CXC), that enables spatially and energy resolved XRF analysis, the absorption of the primary beam was directly visualized for mL-droplets and an array of pL-droplets printed on a Si-wafer with drop-on-demand technology. As expected, deposits that are hit by the primary beam first shade subsequent droplets, leading to a diminished XRF signal. This shading effect was quantified with enhanced precision making use of sub-pixel analysis that improves the spatial resolution of the camera. The measured absorption was compared to simulated results using three different model calculations. It was found they match very well (average deviation < 10%). Thus errors in quantification due to absorption effects can be accounted for in a more accurate manner. KW - absorption KW - X-ray Fluorescence analysis PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-359000 DO - https://doi.org/10.1039/C5JA00127G IS - 10 SP - 2184 EP - 2193 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-35900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - C. Pardo Pérez, L. A1 - Arndt, A. A1 - Stojkovikj, S. A1 - Y. Ahmet, I. A1 - T. Arens,, J. A1 - Dattila, F. A1 - Wendt, R. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Davies, V. A1 - Höflich, K. A1 - Köhnen, E. A1 - Tockhorn, P. A1 - Golnak, R. A1 - Xiao, J. A1 - Schuck, G. A1 - Wollgarten, M. A1 - López, N. A1 - T. Mayer, M. T1 - Determining Structure-Activity Relationships in Oxide Derived CuSn Catalysts During CO2 Electroreduction Using X-Ray Spectroscopy N2 - The development of earth-abundant catalysts for selective electrochemical CO2 conversion is a central challenge. Cu-Sn bimetallic catalysts can yield selective CO2 reduction toward either CO or formate. This study presents oxide-derived Cu-Sn catalysts tunable for either product and seeks to understand the synergetic effects between Cu and Sn causing these selectivity trends. The materials undergo significant transformations under CO2 reduction conditions, and their dynamic bulk and surface structures are revealed by correlating observations from multiple methods—X-ray absorption spectroscopy for in situ study, and quasi in situ X-ray photoelectron spectroscopy for surface sensitivity. For both types of catalysts, Cu transforms to metallic Cu0 under reaction conditions. However, the Sn speciation and content differ significantly between the catalyst types: the CO-selective catalysts exhibit a surface Sn content of 13 at. % predominantly present as oxidized Sn, while the formate-selective catalysts display an Sn content of ≈70 at. % consisting of both metallic Sn0 and Sn oxide species. Density functional theory simulations suggest that Snδ+ sites weaken CO adsorption, thereby enhancing CO selectivity, while Sn0 sites hinder H adsorption and promote formate production. This study reveals the complex dependence of catalyst structure, composition, and speciation with electrochemical bias in bimetallic Cu catalysts. KW - Electrochemical CO2 conversion KW - Cu catalysts KW - X-ray absorption spectroscopy PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547116 DO - https://doi.org/10.1002/aenm.202103328 SN - 1614-6832 VL - 12 IS - 5 SP - 2103328 PB - Wiley-VCH GmbH AN - OPUS4-54711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lopez Meza, Sarynna A1 - Garrabrants, A.C. A1 - van der Sloot, H. A1 - Kosson, D.S. T1 - Comparison of the release of constituents from granular materials under batch and column testing N2 - Column leaching testing can be considered a better basis for assessing field impact data than any other available batch test method and thus provides a fundamental basis from which to estimate constituent release under a variety of field conditions. However, column testing is time-intensive compared to the more simplified batch testing, and may not always be a viable option when making decisions for material reuse. Batch tests are used most frequently as a simple tool for compliance or quality control reasons. Therefore, it is important to compare the release that occurs under batch and column testing, and establish conservative interpretation protocols for extrapolation from batch data when column data are not available. Five different materials (concrete, construction debris, aluminum recycling residue, coal fly ash and bottom ash) were evaluated via batch and column testing, including different column flow regimes (continuously saturated and intermittent unsaturated flow). Constituent release data from batch and column tests were compared. Results showed no significant difference between the column flow regimes when constituent release data from batch and column tests were compared. In most cases batch and column testing agreed when presented in the form of cumulative release. For arsenic in carbonated materials, however, batch testing underestimates the column constituent release for most LS ratios and also on a cumulative basis. For cases when As is a constituent of concern, column testing may be required. KW - Leaching KW - Batch tests KW - Column tests KW - Granular materials PY - 2008 DO - https://doi.org/10.1016/j.wasman.2007.11.009 SN - 0956-053X VL - 28 IS - 10 SP - 1853 EP - 1867 PB - Pergamon Press CY - New York, NY AN - OPUS4-17797 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lopez Meza, Sarynna A1 - van der Sloot, H. A1 - Kosson, D.S. T1 - The effects of intermittent unsaturated wetting on the release of constituents from construction demolition debris N2 - When used in highway applications, granular materials are submitted to changing environmental conditions. While column testing can provide a closer approximation to field percolation conditions than batch testing, there is still a need to develop column testing procedures that more closely approximate realistic conditions. Current column studies are conducted under continuously saturated conditions, without considering unsaturated intermittent flow conditions that exist in the field in response to precipitation events. This study evaluates the effect of different types of column flow on the release of constituents from a granular material. Two different types of intermittent unsaturated flow were studied and compared to continuously saturated flow. Leaching data, including pH, conductivity, and constituent release was compared from the three types of columns. Results showed that there is no difference between the two types of intermittent unsaturated flow, nor is there a significant difference between these two flows and continuously saturated flow, other than higher initial concentrations of salts in intermittent unsaturated flow column testing at low LS ratios. However, this difference is not significant after a LS ratio of 2mL/g. Release of constituents was similar in all three cases. Also, all three cases show that after a LS ratio of 5mL/g there is no significant change in the pH, conductivity or release of constituents. KW - Intermittent flow KW - Column tests KW - Leaching PY - 2009 DO - https://doi.org/10.1089/ees.2007.0337 SN - 1092-8758 SN - 1557-9018 VL - 26 IS - 3 SP - 463 EP - 469 PB - Liebert CY - Larchmont, NY AN - OPUS4-20933 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -