TY - CONF A1 - Shamsuddoha, Md A1 - Hüsken, Götz A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Baeßler, Matthias T1 - Superplasticizer and Shrinkage Reducing Admixture Dosages for Microfine Cement in Grout Systems N2 - Grouts have numerous applications including crack repair as maintenance in construction industries. Microfine cements are intensively used for high strength mortar and grout products. They are ideal for injection grouting in structural repair. Such grouts should have suitable rheological properties to be injectable, especially those used in repair and rehabilitation. The use of superplasticizers (SP) in these products is thus becoming increasingly crucial to achieve favorable workability and viscosity properties. A difficulty in such grouts is the plastic shrinkage due to finer particles used. It is thus necessary to determine optimum SP and shrinkage reducing admixture (SRA) dosages for a microfine cement based grout. In this study, a saturation dosage was decided from two Polycarboxylate ether (PCE) based SPs in relation to neat cement using slump flow and rheological parameters. A range of grout mixtures was formulated containing micro silica (MS) and fly ash (FA), and tested for suitable rheological and mechanical parameters. Based on the results, a grout mixture with MS and FA was selected to determine optimum SRA content. According to the results, a SP dosage of 3% by weight of neat cement is sufficient to achieve saturation. The grout material including MS and FA can produce comparable properties to neat cement grout. MS is found to improve compressive strength within the range considered, whereas a higher FA content provides favourable rheological properties. Finally, a SRA dosage of 4%, which could reduce the shrinkage by about 43% after 28d days, is determined for the grout system. T2 - 2nd International Conference on Building Materials and Materials Engineering (ICBMM 2018) CY - University of Lisbon, Portugal DA - 26.09.2018 KW - Grout KW - Microfine Cement KW - Superplasticizer KW - Supplementary Cementitious Materials KW - Shrinkage Reducing Admixture PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-478319 DO - https://doi.org/10.1051/matecconf/201927801001 VL - 278 SP - Article Number 01001 PB - EDP Sciences AN - OPUS4-47831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mekonnen, Tessema Fenta A1 - Panne, Ulrich A1 - Koch, Matthias T1 - Glucosylation and Glutathione Conjugation of Chlorpyrifos and Fluopyram Metabolites Using Electrochemistry/Mass Spectrometry N2 - Xenobiotics and their reactive metabolites are conjugated with native biomolecules such as glutathione and glucoside during phase II metabolism. Toxic metabolites are usually detoxified during this step. On the other hand, these reactive species have a potential health impact by disrupting many enzymatic functions. Thus, it is crucial to understand phase II conjugation reactions of xenobiotics in order to address their fate and possible toxicity mechanisms. Additionally, conventional methods (in vivo and in vitro) have limitation due to matrix complexity and time-consuming. Hence, developing fast and matrix-free alternative method is highly demandable. In this work, oxidative phase I metabolites and reactive species of chlorpyrifos (insecticide) and fluopyram (fungicide) were electrochemically produced by using a boron-doped diamond electrode coupled online to electrospray mass spectrometry (ESI-MS). Reactive species of the substrates were trapped by biomolecules (glutathione and glucoside) and phase II conjugative metabolites were identified using liquid chromatography (LC)-MS/MS, and/or Triple time of flight (TripleTOF)-MS. Glutathione conjugates and glucosylation of chlorpyrifos, trichloropyridinol, oxon, and monohydroxyl fluopyram were identified successfully. Glutathione and glucoside were conjugated with chlorpyrifos, trichloropyridinol, and oxon by losing a neutral HCl. In the case of fluopyram, its monohydroxyl metabolite was actively conjugated with both glutathione and glucoside. In summary, seven bioconjugates of CPF and its metabolites and two bioconjugates of fluopyram metabolites were identified using electrochemistry (EC)/MS for the first time in this work. The work could be used as an alternative approach to identify glutathione and glucosylation conjugation reactions of other organic compounds too. It is important, especially to predict phase II conjugation within a short time and matrix-free environment. KW - Pesticide KW - Bioconjugation KW - Oxidative metabolism KW - EC/MS PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475932 DO - https://doi.org/10.3390/molecules24050898 VL - 24 IS - 5 SP - 898 EP - 910 PB - MDPI AN - OPUS4-47593 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwaar, Timm A1 - Lettow, Maike A1 - Remmler, Dario A1 - Börner, H. G. A1 - Weller, Michael G. T1 - Efficient Screening of Combinatorial Peptide Libraries by Spatially Ordered Beads Immobilized on Conventional Glass Slides N2 - Screening of one-bead-one-compound (OBOC) libraries is a proven procedure for the identification of protein-binding ligands. The demand for binders with high affinity and specificity towards various targets has surged in the biomedical and pharmaceutical field in recent years. The traditional peptide screening involves tedious steps such as affinity selection, bead picking, sequencing, and characterization. Herein, we present a high-throughput “all-on-one chip” system to avoid slow and technically complex bead picking steps. On a traditional glass slide provided with an electrically conductive tape, beads of a combinatorial peptide library are aligned and immobilized by application of a precision sieve. Subsequently, the chip is incubated with a fluorophore-labeled target protein. In a fluorescence scan followed by matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF) mass spectrometry, high-affinity binders are directly and unambiguously sequenced with high accuracy without picking of the positive beads. The use of an optimized ladder sequencing approach improved the accuracy of the de-novo sequencing step to nearly 100%. The new technique was validated by employing a FLAG-based model system, identifying new peptide binders for the monoclonal M2 anti-FLAG antibody, and was finally utilized to search for IgG-binding peptides. In the present format, more than 30,000 beads can be screened on one slide. KW - Peptide library KW - HTS KW - Target KW - MALDI KW - Mass spectrometry KW - Biochip KW - Lab-on-a-Chip KW - Array KW - Screening KW - Ladder sequencing KW - Binder KW - Pharmaceutical PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-478973 UR - https://www.mdpi.com/2571-5135/8/2/11 DO - https://doi.org/10.3390/ht8020011 VL - 8 IS - 2 SP - 1 EP - 15 PB - MDPI CY - Basel AN - OPUS4-47897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martins, Inês C.B. A1 - Al-Sabbagh, Dominik A1 - Meyer, Klas A1 - Maiwald, Michael A1 - Scholz, G. A1 - Emmerling, Franziska T1 - Insight into the Structure and Properties of Novel Imidazole-Based Salts of Salicylic Acid N2 - The preparation of new active pharmaceutical ingredient (API) multicomponent Crystal forms, especially co-crystals and salts, is being considered as a reliable strategy to improve API solubility and bioavailability. In this study, three novel imidazole-based salts of the poorly water-soluble salicylic acid (SA) are reported exhibiting a remarkable improvement in solubility and dissolution rate properties. All structures were solved by powder X-ray diffraction. Multiple complementary techniques were used to solve co-crystal/salt ambiguities: density functional Theory calculations, Raman and 1H/13C solid-state NMR spectroscopies. In all molecular salts, the Crystal packing interactions are based on a common charged assisted +N-H SA)...O-(co-former) hydrogen bond interaction. The presence of an extra methyl group in different positions of the co-former, induced different supramolecular arrangements, yielding salts with different physicochemical properties. All salts present much higher solubility and dissolution rate than pure SA. The most promising results were obtained for the salts with imidazole and 1-methylimidazole co-formers. KW - Salicylic acid KW - Imidazole KW - Salts KW - Powder X-ray diffraction KW - SsNMR KW - DFT PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502825 DO - https://doi.org/10.3390/molecules24224144 VL - 24 IS - 22 SP - 4144 PB - MDPI AN - OPUS4-50282 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Burek, K. A1 - Dengler, J. A1 - Emmerling, Franziska A1 - Feldmann, Ines A1 - Kumke, M. U. A1 - Stroh, Julia T1 - Lanthanide Luminescence Revealing the Phase Composition in Hydrating Cementitious Systems N2 - The hydration process of Portland cement in a cementitious system is crucial for development of the high-quality cementbased construction material. Complementary experiments of Xray diffraction analysis (XRD), scanning electron microscopy (SEM) and time-resolved laser fluorescence spectroscopy (TRLFS) using europium (Eu(III)) as an optical probe are used to analyse the hydration process of two cement systems in the absence and presence of different organic admixtures. We Show that different analysed admixtures and the used sulphate carriers in each cement system have a significant influence on the hydration process, namely on the time-dependence in the formation of different hydrate phases of cement. Moreover, the effect of a particular admixture is related to the type of sulphate carrier used. The quantitative information on the amounts of the crystalline cement paste components is accessible via XRD analysis. Distinctly different morphologies of ettringite and calcium-silicate-hydrates (C-S-H) determined by SEM allow visual conclusions about formation of these phases at particular ageing times. The TRLFS data provides information about the admixture influence on the course of the silicate reaction. The dip in the dependence of the luminescence decay times on the hydration time indicates the change in the structure of C-S-H in the early hydration period. Complementary information from XRD, SEM and TRLFS provides detailed information on distinct periods of the cement hydration process. KW - Cement admixtures KW - Cement hydration KW - Europium KW - Luminescence KW - SEM KW - X-ray diffraction PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504842 DO - https://doi.org/10.1002/open.201900249 VL - 8 IS - 12 SP - 1441 EP - 1452 PB - Wiley-VCH AN - OPUS4-50484 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zinke, R. A1 - Virothi, N. A1 - Köhler, F. A1 - Klippel, A. A1 - Schalau, Sebastian A1 - Krause, U. T1 - Experimental measurement of initial evaporation mass flows from gasoline spills and comparison with empirical models N2 - In this paper, we investigate the evaporation mass flow originating from spills of gas-oline. Large spills of gasoline may form during partial or complete roof sinkings or inthe case of perforations at various deck fittings at external floating roof tanks usedfor the storage. Additionally, spills may form in the retention area in the case of leak-ages at pipes or at the hull. The aim is to predict the order of magnitude of real-scaleevaporation mass flow. The determined evaporation mass flows will be used in arelated project as input values for subsequent dispersion modeling in the vicinity ofthe tanks. This is relevant for questions of fire and explosion protection as well as forenvironmental protection aspects in tank farms or refineries, which use externalfloating roof tanks. The measurements presented in this paper were compared withpredictions by empirical models and investigations of evaporations from small floorspills, round-bottom flask, or from Petri dishes published in the literature. The maingoal of this paper is to test the applicability of empirical models to provide reasonableevaporation mass flows as input for CFD dispersion simulations. KW - Spill evaporation PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504322 DO - https://doi.org/10.1002/prs.12128 VL - 39 IS - 3 SP - e12128 PB - Wiley Online Libary AN - OPUS4-50432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Vallée, A. A1 - Bally, P. A1 - Bruel, C. A1 - Chandat, L. A1 - Choquer, M. A1 - Dieryckx, C. A1 - Dupuy, J.W. A1 - Kaiser, S. A1 - Latorse, M.-P. A1 - Loisel, E. A1 - Mey, G. A1 - Morgant, G. A1 - Rascle, C. A1 - Schumacher, Julia A1 - Simon, A. A1 - Souibgui, E. A1 - Viaud, M. A1 - Villalba, F. A1 - Poussereau, N. T1 - A similar secretome disturbance as a hallmark of non-pathogenic Botrytis cinerea ATMT-mutants? N2 - The gray mold fungus Botrytis cinerea is a necrotrophic pathogen able to infect hundreds of host plants, including high-value crops such as grapevine, strawberry and tomato. In order to decipher its infectious strategy, a library of 2,144 mutants was generated by random insertional mutagenesis using Agrobacterium tumefaciensmediated transformation (ATMT). Twelve mutants exhibiting total loss of virulence toward different host plants were chosen for detailed analyses. Their molecular characterization revealed a single T-DNA insertion in different loci. Using a proteomics approach, the secretome of four of these strains was compared to that of the parental strain and a common profile of reduced lytic enzymes was recorded. Significant variations in this profile, notably deficiencies in the secretion of proteases and hemicellulases, were observed and validated by biochemical tests. They were also a hallmark of the remaining eight non-pathogenic strains, suggesting the importance of these secreted Proteins in the infection process. In the twelve non-pathogenic mutants, the Differentiation of infection cushions was also impaired, suggesting a link between the Penetration structures and the secretion of proteins involved in the virulence of the pathogen. KW - Fungus KW - Plant pathogen KW - Virulence PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502710 DO - https://doi.org/10.3389/fmicb.2019.02829 SN - 1664-302X VL - 10 SP - Article 2829 PB - Frontiers Media CY - Lausanne AN - OPUS4-50271 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kembuan, C. A1 - Saleh, Maysoon I. A1 - Rühle, Bastian A1 - Resch-Genger, Ute A1 - Graf, C. T1 - Coating of upconversion nanoparticles with silica nanoshells of 5–250 nm thickness N2 - A concept for the growth of silica shells with a thickness of 5–250 nm onto oleate-coated NaYF4:Yb3+/Er3+ upconversion nanoparticles (UCNP) is presented. The concept enables the precise adjustment of shell thicknesses for the preparation of thick-shelled nanoparticles for applications in plasmonics and sensing. First, an initial 5–11 nm thick shell is grown onto the UCNPs in a reverse microemulsion. This is followed by a stepwise growth of these particles without a purification step, where in each step equal volumes of tetraethyl orthosilicate and ammonia water are added, while the volumes of cyclohexane and the surfactant Igepal® CO-520 are increased so that the ammonia water and surfactant concentrations remain constant. Hence, the number of micelles stays constant, and their size is increased to accommodate the growing core–shell particles. Consequently, the formation of core-free silica particles is suppressed. When the negative zeta potential of the particles, which continuously decreased during the stepwise growth, falls below −40 mV, the particles can be dispersed in an ammoniacal ethanol solution and grown further by the continuous addition of tetraethyl orthosilicate to a diameter larger than 500 nm. Due to the high colloidal stability, a coalescence of the particles can be suppressed, and single-core particles are obtained. This strategy can be easily transferred to other nanomaterials for the design of plasmonic nanoconstructs and sensor systems. KW - Reverse microemulsion KW - Silica coating KW - Stepwise growth KW - Thick shells KW - Upconversion nanoparticles PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502769 DO - https://doi.org/10.3762/bjnano.10.231 SN - 2190-4286 VL - 10 SP - 2410 EP - 2421 PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften CY - Frankfurt, M. AN - OPUS4-50276 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Melzer, Michael A1 - Makarov, D. A1 - Schmidt, O. G. T1 - A review on stretchable magnetic field sensorics N2 - The current establishment of stretchable electronics to form a seamless link between soft or even living materials and the digital world is at the forefront of multidisciplinary research efforts, bridging physics, engineering and materials science. Magnetic functionalities can provide a sense of displacement, orientation or proximity to this novel formulation of electronics. This work reviews the recent development of stretchable magnetic field sensorics relying on the combination of metallic thin films revealing a giant magnetoresistance effect with elastomeric materials. Stretchability of the magnetic nanomembranes is achieved by specific morphologic features (e.g. wrinkles or microcracks), which accommodate the applied tensile deformation while maintaining the electrical and magnetic integrity of the sensor device. The entire development, from the demonstration of the world’s first elastically stretchable magnetic sensor to the realization of a technology platform for robust, ready-to-use elastic magnetosensorics is described. Soft giant magnetoresistive elements exhibiting the same sensing performance as on conventional rigid supports, but with fully strain invariant properties up to 270% stretching have been demonstrated. With their unique mechanical properties, these sensor elements readily conform to ubiquitous objects of arbitrary shapes including the human skin. Stretchable magnetoelectronic sensors can equip soft and epidermal electronic systems with navigation, orientation, motion tracking and touchless control capabilities. A variety of novel technologies, like electronic skins, smart textiles, soft robotics and actuators, active medical implants and soft consumer electronics will benefit from these new magnetic functionalities. KW - Stretchable electronics KW - Giant magnetoresistance KW - Magnetic sensors KW - Magnetic thin films PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502049 DO - https://doi.org/10.1088/1361-6463/ab52cf SN - 0022-3727 (Druck) SN - 1361-6463 (Web) VL - 53 IS - 8 SP - Paper 083002, 34 PB - IOP Publishing AN - OPUS4-50204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Javaheri, E. A1 - Lubritz, J. A1 - Graf, B. A1 - Rethmeier, Michael T1 - Mechanical Properties Characterization of Welded Automotive Steels N2 - Among the various welding technologies, resistance spot welding (RSW) and laser beam welding (LBW) play a significant role as joining methods for the automobile industry. The application of RSW and LBW for the automotive body alters the microstructure in the welded areas. It is necessary to identify the mechanical properties of the welded material to be able to make a reliable statement about the material behavior and the strength of welded components. This study develops a method by which to determine the mechanical properties for the weldment of RSW and LBW for two dual phase (DP) steels, DP600 and DP1000, which are commonly used for the automotive bodies. The mechanical properties of the resistance spot weldment were obtained by performing tensile tests on the notched tensile specimen to cause an elongation of the notched and welded area in order to investigate its properties. In order to determine the mechanical properties of the laser beam weldment, indentation tests were performed on the welded material to calculate its force-penetration depth-curve. Inverse numerical simulation was used to simulate the indentation tests to determine and verify the parameters of a nonlinear isotropic material model for the weldment of LBW. Furthermore, using this method, the parameters for the material model of RSW were verified. The material parameters and microstructure of the weldment of RSW and LBW are compared and discussed. The results show that the novel method introduced in this work is a valid approach to determine the mechanical properties of welded high-strength steel structures. In addition, it can be seen that LBW and RSW lead to a reduction in ductility and an increase in the amount of yield and tensile strength of both DP600 and DP1000. KW - Mechanical property KW - Laser beam welding KW - Dual phase steel KW - Resistance spot welding PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502269 DO - https://doi.org/10.3390/met10010001 VL - 10 IS - 1 SP - 1 EP - 20 PB - MDPI AN - OPUS4-50226 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kneipp, Janina A1 - Zancajo, Victor M.R. A1 - Diehn, S. A1 - Filiba, N. A1 - Elbaum, R. T1 - Spectroscopic Discrimination of Sorghum Silica Phytoliths N2 - Grasses accumulate silicon in the form of silicic acid, which is precipitated as amorphous silica in microscopic particles termed phytoliths. These particles comprise a variety of morphologies according to the cell type in which the silica was deposited. Despite the evident morphological differences, phytolith chemistry has mostly been analysed in bulk samples, neglecting differences between the varied types formed in the same species. In this work, we extracted leaf phytoliths from mature plants of Sorghum bicolor (L.) Moench. Using solid state NMR and thermogravimetric analysis, we show that the extraction methods alter greatly the silica molecular structure, its condensation degree and the trapped organic matter. Measurements of individual phytoliths by Raman and synchrotron FTIR microspectroscopies in combination with multivariate analysis separated bilobate silica cells from prickles and long cells, based on the silica molecular structures and the fraction and composition of occluded organic matter. The variations in structure and composition of sorghum phytoliths suggest that the biological pathways leading to silica deposition vary between these cell types. KW - Phytoliths KW - Biosilicification KW - Raman KW - Sorghum KW - Solid state NMR KW - Synchrotron FTIR PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502672 DO - https://doi.org/10.3389/fpls.2019.01571 VL - 10 SP - 1571 PB - Frontiers Media CY - Lausanne AN - OPUS4-50267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baer, Wolfram T1 - Chunky graphite in ferritic spheroidal graphite cast iron: Formation, prevention, characterization, impact on properties – An overview N2 - Ferritic spheroidal graphite cast iron (SGI) materials have a remarkable technical poten-tial and economic impact in modern industry. These features are closely related to the question of how the cast materials can be produced without structural defects and graphite degenerations such as for example chunky graphite. Although the chunky graphite degeneration superficially seems to be well known, its metallurgical background is still controversially discussed, appropriate field-tested non-destructive tools for its quantification in castings are lacking and the knowledge on its impact on material properties is fairly limited. Addressing this status, the article is providing a current overview on the subject. Existing theories on formation and growth mechanisms of chunky graphite are briefly reviewed. Furthermore, from a metallurgical point of view, causes for the appearance of chunky graphite as well as preventive measures are concisely summarized. Particular attention is paid to the morphology of chunky graphite and how it can be characterized by destructive and non-destructive techniques. Special emphasis was laid on providing a comprehensive overview on the impact of chunky graphite on strength, ductility, fatigue limit, fatigue crack growth rate as well as fracture tough-ness of ferritic SGI materials based on experimental data. Moreover, conclusions for the assessment of castings affected by chunky graphite are drawn. KW - Characterization KW - Ferritic spheroidal graphite cast iron KW - Chunky graphite KW - Properties KW - Formation KW - Prevention PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499972 DO - https://doi.org/10.1007/s40962-019-00363-8 SN - 1939-5981 SN - 2163-3193 VL - 14 IS - 2 SP - 454 EP - 488 PB - Springer Verlag AN - OPUS4-49997 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sentker, K. A1 - Yildirim, Arda A1 - Lippmann, M. A1 - Zantop, A. W. A1 - Bertram, F. A1 - Hofmann, T. A1 - Seeck, O. H. A1 - Kityk, A. A1 - Mazza, M. G. A1 - Schönhals, Andreas A1 - Huber, P. T1 - Self-assembly of liquid crystals in nanoporous solids for adaptive photonic metamaterials N2 - Nanoporous media exhibit structures significantly smaller than the wavelengths of visible light and can thus act as photonic metamaterials. Their optical functionality is not determined by the properties of the base materials, but rather by tailored, multiscale structures, in terms of precise pore shape, geometry, and orientation. Embedding liquid crystals in pore space provides additional opportunities to control light–matter interactions at the single-pore, meta-atomic scale. Here, we present temperature-dependent 3D reciprocal space mapping using synchrotron-based X-ray diffraction in combination with high-Resolution birefringence experiments on disk-like mesogens (HAT6) imbibed in self-ordered arrays of parallel cylindrical pores 17 to 160 nm across in monolithic anodic aluminium oxide (AAO). In agreement with Monte Carlo computer simulations we observe a remarkably rich self-assembly behaviour, unknown from the bulk state. It encompasses transitions between the isotropic liquid state and discotic stacking in linear columns as well as circular concentric ring formation perpendicular and parallel to the pore axis. These textural transitions underpin an optical birefringence functionality, tuneable in magnitude and in sign from positive to negative via pore size, pore surface-grafting and temperature. Our study demonstrates that the advent of large-scale, self-organised nanoporosity in monolithic solids along with confinement-controllable phase behaviour of liquid-crystalline matter at the single-pore scale provides a reliable and accessible tool to design materials with adjustable optical anisotropy, and thus offers versatile pathways to finetune polarisation-dependent light propagation speeds in materials. Such a tailorability is at the core of the emerging field of transformative optics, allowing, e.g., adjustable light absorbers and extremely thin metalenses. KW - Discotic Liquid Crystals PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499601 DO - https://doi.org/10.1039/c9nr07143a SP - 1 EP - 14 PB - RSC Royal Society of Chemistry AN - OPUS4-49960 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias T1 - Sub-stoichiometric oxides for wear resistance N2 - In the present work it was shown that the tribologcal profiles of special model oxides under dry unidirectional sliding have shown, that sub-oxides have a contribution to the tribological behavior of carbides and cermets, when they are tribo-oxidatively formed, because their tribological profiles as monolithic materials are homologous in part or totally, or compete with hardmetals or cermets, depending from the operating conditions regarded. KW - Sub-oxide KW - Friction KW - Wear KW - Carbide KW - Hardmetal PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498154 DO - https://doi.org/10.1016/j.wear.2019.203104 SN - 0043-1648 N1 - Eine identische Version zu diesem Artikel wurde publiziert unter: Wear 438-439 (2019) 102735, https://doi.org/10.1016/j.wear.2019.01.066 - An identical version to this article was published under: Wear 438-439 (2019) 102735, https://doi.org/10.1016/j.wear.2019.01.066 VL - 440-441 SP - 203104-1 EP - 203104-7 PB - Elsevier CY - Amsterdam AN - OPUS4-49815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aristia, Gabriela A1 - Le, Quynh Hoa A1 - Bäßler, Ralph T1 - Corrosion of Carbon Steel in Artificial Geothermal Brine: Influence of Carbon Dioxide at 70 °C and 150 °C N2 - This study focuses on the corrosion mechanism of carbon steel exposed to an artificial geothermal brine influenced by carbon dioxide (CO2) gas. The tested brine simulates a geothermal source in Sibayak, Indonesia, containing 1500 mg/L of Cl-, 20 mg/L of SO4 2-, and 15 mg/L of HCO3-with pH 4. To reveal the temperature effect on the corrosion behavior of carbon steel, exposure and electrochemical tests were carried out at 70 °C and 150 °C. Surface analysis of corroded specimens showed localized corrosion at both temperatures, despite the formation of corrosion products on the surface. After 7 days at 150 °C, SEM images showed the formation of an adherent, dense, and crystalline FeCO3 layer. Whereas at 70 °C, the corrosion products consisted of chukanovite (Fe2(OH)2CO3) and siderite (FeCO3), which are less dense and less protective than that at 150 °C. Control experiments under Ar-environment were used to investigate the corrosive effect of CO2. Free corrosion potential (Ecorr) and electrochemical impedance spectroscopy (EIS) confirm that at both temperatures, the corrosive effect of CO2 was more significant compared to that measured in the Ar-containing solution. In terms of temperature effect, carbon steel remained active at 70 °C, while at 150 °C, it became passive due to the FeCO3 formation. These results suggest that carbon steel is more susceptible to corrosion at the near ground surface of a geothermal well, whereas at a deeper well with a higher temperature, there is a possible risk of scaling (FeCO3 layer). A longer exposure test at 150 °C with a stagnant solution for 28 days, however, showed the unstable FeCO3 layer and therefore a deeper localized corrosion compared to that of seven-day exposed specimens. KW - Carbon steel KW - CO2 KW - Corrosion KW - Electrochemical impedance spectroscopy KW - Geothermal PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498168 DO - https://doi.org/10.3390/ma12223801 SN - 1996-1944 VL - 12 IS - 22 SP - 3801-1 EP - 20 PB - MDPI CY - Basel AN - OPUS4-49816 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stajanca, Pavol A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Distributed Fiberoptic Sensor for Simultaneous Humidity and Temperature Monitoring Based on Polyimide-Coated Optical Fibers N2 - Along temperature, humidity is one of the principal environmental factors that plays an important role in various application areas. Presented work investigates possibility of distributed fiberoptic humidity monitoring based on humidity-induced strain measurement in polyimide (PI)-coated optical fibers. Characterization of relative humidity (RH) and temperature response of four different commercial PI- and one acrylate-coated fiber was performed using optical backscattering reflectometry (OBR). The study addresses issues of temperature-humidity cross sensitivity, fiber response stability, repeatability, and the influence of annealing. Acrylate-coated fiber exhibited rather unfavorable nonlinear RH response with strong temperature dependence, which makes it unsuitable for humidity sensing applications. On the other hand, humidity response of PI-coated fibers showed good linearity with fiber sensitivity slightly decreasing at rising temperatures. In the tested range, temperature sensitivity of the fibers remained humidity independent. Thermal annealing was shown to considerably improve and stabilize fiber RH response. Based on performed analysis, a 20 m sensor using the optimal PI-coated fibers was proposed and constructed. The sensor uses dual sensing fiber configuration for mutual decoupling and simultaneous measurement of temperature and RH variations. Using OBR, distributed dual temperature-RH monitoring with cm spatial resolution was demonstrated for the first time. KW - Distributed humidity sensing KW - Fiberoptic sensors KW - Polyimide-coated optical fibers KW - Optical frequency-domain reflectometry KW - Dual sensing PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498871 DO - https://doi.org/10.3390/s19235279 VL - 19 IS - 23 SP - 5279 PB - MDPI AN - OPUS4-49887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hicke, Konstantin A1 - Eisermann, René A1 - Chruscicki, Sebastian T1 - Enhanced Distributed Fiber Optic Vibration Sensing and Simultaneous Temperature Gradient Sensing Using Traditional C-OTDR and Structured Fiber with Scattering Dots N2 - We present results demonstrating several beneficial effects on distributed fiber optic vibration sensing (DVS) functionality and performance resulting from utilizing standard single mode optical fiber (SMF) with femtosecond laser-inscribed equally-spaced simple scattering dots. This modification is particularly useful when using traditional single-wavelength amplitude-based coherent optical time domain reflectometry (C-OTDR) as sensing method. Local sensitivity is increased in quasi-distributed interferometric sensing zones which are formed by the fiber segments between subsequent pairs of the scattering dots. The otherwise nonlinear transfer function is overwritten with that of an ordinary two-beam interferometer. This linearizes the phase response to monotonous temperature variations. Furthermore, sensitivity fading is mitigated and the demodulation of low-frequency signals is enabled. The modification also allows for the quantitative determination of local temperature gradients directly from the C-OTDR intensity traces. The dots’ reflectivities and thus the induced attenuation can be tuned via the inscription process parameters. Our approach is a simple, robust and cost-effective way to gain these sensing improvements without the need for more sophisticated interrogator technology or more complex fiber structuring, e.g., based on ultra-weak FBG arrays. Our claims are substantiated by experimental evidence. KW - Fiber optic sensors KW - Distributed vibration sensing KW - DVS KW - Distributed temperature gradient sensing KW - DTGS KW - C-OTDR KW - Phase-sensitive KW - OTDR KW - Fiber structuring KW - Fs-inscription PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499281 DO - https://doi.org/10.3390/s19194114 VL - 19 IS - 19 SP - 4114 PB - MDPI CY - Basel, Switzerland AN - OPUS4-49928 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nöller, Renate A1 - Danielewski, A. A1 - Giel, R. A1 - Overgaauw, E. A1 - Hahn, Oliver T1 - Material analysis of Aztec codices in Berlin. Assignment of small fragments compiled as cutouts on one plate in Humboldt’s “Atlas pittoresque du voyage” N2 - The collection Manuscripta Americana in Berlin consists of fragmented codices acquired by Alexander von Humboldt in Mexico. Some of these Humboldt Codices are published as hieroglyphic writings of the Aztecs in “Vues des Cordilleres et Monuments des Peuples indigènes de l’Amerique”. Starting from a special compilation of seven fragments on plate 36 in the “Atlas”, we investigated the corresponding original fragments using material analysis in order to clarify their historical relations. The analyses were carried out with X-ray fluorescence analysis, VIS spectroscopy, and infrared spectroscopy in diffuse reflection and revealed typical indigenous colors like cochineal, indigo, and organic yellows (e.g. mangrove and zacatlaxcalli). Four fragments under investigation show exactly the same material and thus must once have belonged together in one compendium. An additional manuscript from Mizquiahuala also shown on plate 36 can be matched to another one that is not published in the “Atlas”. KW - Manuscripts KW - Alexander von Humboldt KW - Non-destructiv testing KW - Colourants KW - Writing materials PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498971 DO - https://doi.org/10.1080/20548923.2019.1682816 SN - 2054-8923 SP - 1 EP - 14 PB - Routledge, Taylor & Francis Group CY - London AN - OPUS4-49897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Greco, A. A1 - Starostin, V. A1 - Karapanagiotis, C. A1 - Hinderhofer, A. A1 - Gerlach, A. A1 - Pithan, L. A1 - Liehr, Sascha A1 - Schreiber, Frank A1 - Kowarik, Stefan T1 - Fast fitting of reflectivity data of growing thin films using neural networks N2 - X-ray reflectivity (XRR) is a powerful and popular scattering technique that can give valuable insight into the growth behavior of thin films. This study Shows how a simple artificial neural network model can be used to determine the thickness, roughness and density of thin films of different organic semiconductors [diindenoperylene, copper(II) phthalocyanine and alpha-sexithiophene] on silica from their XRR data with millisecond computation time and with minimal user input or a priori knowledge. For a large experimental data set of 372 XRR curves, it is shown that a simple fully connected model can provide good results with a mean absolute percentage error of 8–18% when compared with the results obtained by a genetic least mean squares fit using the classical Parratt formalism. Furthermore, current drawbacks and prospects for improvement are discussed. KW - Artificial neural networks KW - X-ray reflectivity PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498997 DO - https://doi.org/10.1107/S1600576719013311 SN - 1600-5767 VL - 52 SP - 1342 EP - 1347 PB - Wiley AN - OPUS4-49899 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kockert, M. A1 - Mitdank, R. A1 - Zykov, A. A1 - Kowarik, Stefan A1 - Fischer, F. T1 - Absolute Seebeck coefficient of thin platinum films N2 - The influence of size effects on the thermoelectric properties of thin platinum films is investigated and compared to the bulk. Structural properties, like the film thickness and the grain size, are varied. We correlate the electron mean free path with the temperature dependence of the electrical conductivity and the absolute Seebeck coefficient SPt of platinum. A measurement platform was developed as a standardized method to determine SPt and show that SPt,film is reduced compared to SPt,bulk. Boundary and surface scattering reduce the thermodiffusion and the phonon drag contribution to SPt,film by nearly the same factor. We discuss in detail on behalf of a model, which describes the temperature dependence of the absolute Seebeck coefficient, the influence of size effects of electron-phonon and phonon-phonon interaction on SPt. KW - Thin magnetic films PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499007 DO - https://doi.org/10.1063/1.5101028 SN - 0021-8979 VL - 126 SP - 105106 PB - AIP AN - OPUS4-49900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Büchele, Dominique A1 - Chao, Madlen A1 - Ostermann, Markus A1 - Leenen, M. A1 - Bald, Ilko T1 - Multivariate chemometrics as a key tool for prediction of K and Fe in a diverse German agricultural soil-set using EDXRF N2 - Within the framework of precision agriculture, the determination of various soil properties is moving into focus, especially the demand for sensors suitable for in-situ measurements. Energy-dispersive X-ray fluorescence (EDXRF) can be a powerful tool for this purpose. In this study a huge diverse soil set (n = 598) from 12 different study sites in Germany was analysed with EDXRF. First, a principal component analysis (PCA) was performed to identify possible similarities among the sample set. Clustering was observed within the four texture classes clay, loam, silt and sand, as clay samples contain high and sandy soils low iron mass fractions. Furthermore, the potential of uni- and multivariate data evaluation with partial least squares regression (PLSR) was assessed for accurate Determination of nutrients in German agricultural samples using two calibration sample sets. Potassium and iron were chosen for testing the performance of both models. Prediction of these nutrients in 598 German soil samples with EDXRF was more accurate using PLSR which is confirmed by a better overall averaged deviation and PLSR should therefore be preferred. KW - XRF KW - Chemometrics KW - Soil KW - Agriculture KW - Multivariate PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498671 DO - https://doi.org/10.1038/s41598-019-53426-5 VL - 9 SP - 17588 PB - Nature AN - OPUS4-49867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nirmalananthan-Budau, Nithiya A1 - Rühle, Bastian A1 - Geißler, Daniel A1 - Moser, Marko A1 - Kläber, Christopher A1 - Schäfer, A. A1 - Resch-Genger, Ute T1 - Multimodal cleavable reporters for quantifying carboxy and amino groups on organic and inorganic nanoparticles N2 - Organic and inorganic nanoparticles (NPs) are increasingly used as drug carriers, fluorescent sensors, and multimodal labels in the life and material sciences. These applications require knowledge of the chemical nature, total number of surface groups, and the number of groups accessible for subsequent coupling of e.g., antifouling ligands, targeting bioligands, or sensor molecules. To establish the concept of catch-and-release assays, cleavable probes were rationally designed from a quantitatively cleavable disulfide moiety and the optically detectable reporter 2-thiopyridone (2-TP). For quantifying surface groups on nanomaterials, first, a set of monodisperse carboxy-and amino-functionalized, 100 nm-sized polymer and silica NPs with different surface group densities was synthesized. Subsequently, the accessible functional groups (FGs) were quantified via optical spectroscopy of the cleaved off reporter after its release in solution. Method validation was done with inductively coupled plasma optical emission spectroscopy (ICP-OES) utilizing the sulfur atom of the cleavable probe. This comparison underlined the reliability and versatility of our probes, which can be used for surface group quantification on all types of transparent, scattering, absorbing and/or fluorescent particles. The correlation between the total and accessible number of FGs quantified by conductometric titration, qNMR, and with our cleavable probes, together with the comparison to results of conjugation studies with differently sized biomolecules reveal the potential of catch-and-release reporters for surface analysis. Our findings also underline the importance of quantifying particularly the accessible amount of FGs for many applications of NPs in the life sciences. KW - Advanced Materials KW - Surface Chemistry KW - Organic–inorganic nanostructures KW - Funtional Groups KW - Quantitative Analysis PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499081 DO - https://doi.org/10.1038/s41598-019-53773-3 VL - 9 SP - 17577-1 EP - 17577-11 PB - Springer Nature CY - London AN - OPUS4-49908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liu, H. A1 - Song, W. A1 - Gröninger, Delia A1 - Zhang, L. A1 - Lu, Y. A1 - Chan, K. S. A1 - Zhou, Z. A1 - Rurack, Knut A1 - Shen, Z. T1 - Real-time monitoring of newly acidified organelles during autophagy enabled by reaction-based BODIPY dyes N2 - Real-time monitoring of newly acidified organelles during autophagy in living cells is highly desirable for a better understanding of intracellular degradative processes. Herein, we describe a reaction-based boron dipyrromethene (BODIPY) dye containing strongly electron-withdrawing diethyl 2-cyanoacrylate groups at the α-positions. The probe exhibits intense red fluorescence in acidic organelles or the acidified cytosol while negligible fluorescence in other regions of the cell. The underlying mechanism is a nucleophilic reaction at the central meso-carbon of the indacene core, resulting in the loss of π-conjugation entailed by dramatic spectroscopic changes of more than 200 nm between its colorless, non-fluorescent leuco-BODIPY form and its red and brightly emitting form. The reversible transformation between red fluorescent BODIPY and leuco-BODIPY along with negligible cytotoxicity qualifies such dyes for rapid and direct intracellular lysosome imaging and cytosolic acidosis detection simultaneously without any washing step, enabling the real-time monitoring of newly acidified organelles during autophagy. KW - Autophagy KW - BODIPY KW - Fluorescence KW - Lysosome KW - Real-time imaging PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498358 UR - https://www.nature.com/articles/s42003-019-0682-1 DO - https://doi.org/10.1038/s42003-019-0682-1 SN - 23993642 VL - 2 SP - 442 PB - Nature Research CY - London AN - OPUS4-49835 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mezera, M. A1 - Bonse, Jörn A1 - Römer, G.R.B.E. T1 - Influence of Bulk Temperature on Laser-Induced Periodic Surface Structures on Polycarbonate N2 - In this paper, the influence of the bulk temperature (BT) of Polycarbonate (PC) on the occurrence and growth of Laser-induced Periodic Surface Structures (LIPSS) is studied. Ultrashort UV laser pulses with various laser peak fluence levels F_0 and various numbers of overscans (N_OS) were applied on the surface of pre-heated Polycarbonate at different bulk temperatures. Increased BT leads to a stronger absorption of laser energy by the Polycarbonate. For N_OS < 1000 High Spatial Frequency LIPSS (HSFL), Low Spatial Frequency LIPSS perpendicular (LSFL-I) and parallel (LSFL-II) to the laser polarization were only observed on the rim of the ablated tracks on the surface but not in the center of the tracks. For N_OS ≥ 1000 , it was found that when pre-heating the polymer to a BT close its glass transition temperature (T_g), the laser fluence to achieve similar LIPSS as when processed at room temperature decreases by a factor of two. LSFL types I and II were obtained on PC at a BT close to T_g and their periods and amplitudes were similar to typical values found in the literature. To the best of the author’s knowledge, it is the first time both LSFL types developed simultaneously and consistently on the same sample under equal laser processing parameters. The evolution of LIPSS from HSFL, over LSFL-II to LSFL I, is described, depending on laser peak fluence levels, number of pulses processing the spot and bulk temperature. KW - Laser-induced periodic surface structures (LIPSS) KW - Polycarbonate KW - Bulk temperature KW - Ultrashort laser pulses PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498242 UR - https://www.mdpi.com/2073-4360/11/12/1947 DO - https://doi.org/https://doi.org/10.3390/polym11121947 SN - 2073-4360 VL - 11 IS - 12 SP - 1947 PB - MDPI CY - Basel, Switzerland AN - OPUS4-49824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strangfeld, Christoph A1 - Johann, Sergej A1 - Bartholmai, Matthias T1 - Smart RFID Sensors Embedded in Building Structures for Early Damage Detection and Long-Term Monitoring N2 - In civil engineering, many structures are made of reinforced concrete. Most Degradation processes relevant to this material, e.g., corrosion, are related to an increased level of material moisture. Therefore, moisture monitoring in reinforced concrete is regarded as a crucial method for structural health monitoring. In this study, passive radio frequency identification (RFID)-based sensors are embedded into the concrete. They are well suited for long-term operation over decades and are well protected against harsh environmental conditions. The energy supply and the data transfer of the humidity sensors are provided by RFID. The sensor casing materials are optimised to withstand the high alkaline environment in concrete, having pH values of more than 12. Membrane materials are also investigated to identify materials capable of enabling water vapour transport from the porous cement matrix to the embedded humidity sensor. By measuring the corresponding relative humidity with embedded passive RFID-based sensors, the cement hydration is monitored for 170 days. Moreover, long-term moisture monitoring is performed for more than 1000 days. The Experiments show that embedded passive RFID-based sensors are highly suitable for long-term structural health monitoring in civil engineering. KW - RFID based sensors KW - Embedded sensors KW - Corresponding relative humidity KW - Porous building materials KW - Reinforced concrete KW - Corrosion KW - Civil engineering PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500831 DO - https://doi.org/10.3390/s19245514 VL - 19 IS - 24 SP - 1 EP - 18 PB - MDPI CY - Basel, Swiss AN - OPUS4-50083 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lu, Z. A1 - Haist, M. A1 - Ivanov, D. A1 - Jakob, C. A1 - Jansen, D. A1 - Leinitz, Sarah A1 - Link, J. A1 - Mechtcherine, V. A1 - Neubauer, J. A1 - Plank, J. A1 - Schmidt, Wolfram A1 - Schilde, C. A1 - Schröfl, C. A1 - Sowoidnich, T. A1 - Stephan, D. T1 - Characterization data of reference cement CEM I 42.5 R used for Priority Program DFG SPP 2005 “Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials” N2 - A thorough characterization of starting materials is the precondition for further research, especially for cement, which contains various phases and presents quite a complex material for fundamental scientific investigation. In the paper at hand, the characterization data of the reference cement CEM I 42.5 R used within the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented from the aspects of chemical and mineralogical compositions as well as physical and chemical properties. The data were collected based on tests conducted by nine research groups involved in this cooperative program. For all data received, the mean values and the corresponding errors were calculated. The results shall be used for the ongoing research within the priority program. KW - Portland cement KW - Characterization KW - DFG SPP 2005 PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500849 DO - https://doi.org/10.1016/j.dib.2019.104699 SN - 2352-3409 VL - 27 SP - 104699 PB - Elsevier Inc. AN - OPUS4-50084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gharaati, S. A1 - Wang, Cui A1 - Förster, C. A1 - Weigert, Florian A1 - Resch-Genger, Ute A1 - Heinze, K. T1 - Triplet–Triplet Annihilation Upconversion in a MOF with AcceptorFilled Channels N2 - In summary, we report a highly modular solid TTA-UC system comprising of a crystalline, thermally stable PCN222(Pd) MOF with CA-coated MOF channels and with a DPA annihilator embedded in a solution-like environment in the MOF channels. This solid material displays blue upconverted delayed emission with a luminescence lifetime of 373 us, a threshold value of 329 mW*cm-2 and a triplet–triplet energy transfer efficiency of 82%. This optical application adds another facet to the versatile chemistry of PCN-222 MOFs. The design concept is also applicable to other TTA-UC pairs and enables tuning of the UCL color, for example, by replacing DPA with other dyes as exemplarily shown for 2,5,8,11-tetra-tert-butyl-perylene, that yields UCL at 450 nm. Current work aims to reduce the oxygen sensitivity and to increase the retention of the trapped annihilators in organic environments, for example, by tuning the chain length of the carboxylic acid and by coating the MOF surface. In addition, the TTA-UC efficiency will be further enhanced by reducing the reabsorption of the UC emission caused by Pd(TCPP) and by optimizing the sensitizer/annihilator interface. KW - Porphyrin KW - Method KW - MOF KW - Fluorescence KW - Dye KW - Sensor KW - Oxygen sensitive KW - Single molecule KW - DPA KW - Lifetime KW - Upconverstion KW - Quantum yield KW - Triplet-triplet annihilation KW - Sensitization KW - Energy transfer KW - NMR PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500580 DO - https://doi.org/10.1002/chem.201904945 VL - 26 IS - 5 SP - 1003 EP - 1007 PB - Wiley-VCH Verlag CY - Weinheim AN - OPUS4-50058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sebald, M.A. A1 - Gebauer, J. A1 - Sommerfeld, Thomas A1 - Koch, Matthias T1 - First Synthesis of (−)-Altenuene-D3 Suitable as Internal Standard for Isotope Dilution Mass Spectrometry N2 - Metabolites from Alternaria fungi exhibit a variety of biological properties such as phytotoxic, cytotoxic, or antimicrobial activity. Optimization of a literature procedure culminated in an efficient total synthesis of (−)-altenuene as well as a stable isotope-labeled derivative suitable for implementation in a LC-MS/MS method for mycotoxin analysis. KW - Altenuene KW - Alternaria mycotoxins KW - Food safety KW - Isotope-labeled KW - SIDA-LC-MS/MS KW - Suzuki coupling PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500696 DO - https://doi.org/10.3390/molecules24244563 SN - 1420-3049 VL - 24 SP - 4563 PB - MDPI CY - Basel AN - OPUS4-50069 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kindrachuk, Vitaliy A1 - Fedelich, Bernard A1 - Rehmer, Birgit A1 - Peter, Frauke T1 - Computational methods for lifetime prediction of metallic components under high-temperature fatigue N2 - The issue of service life prediction of hot metallic components subjected to cyclic loadings is addressed. Two classes of lifetime models are considered, namely, the incremental lifetime rules and the parametric models governed by the fracture mechanics concept. Examples of application to an austenitic cast iron are presented. In addition, computational techniques to accelerate the time integration of the incremental models throughout the fatigue loading history are discussed. They efficiently solve problems where a stabilized response of a component is not observed, for example due to the plastic strain which is no longer completely reversed and accumulates throughout the fatigue history. The performance of such an accelerated Integration technique is demonstrated for a finite element simulation of a viscoplastic solid under repeating loading–unloading cycles. KW - Fatigue KW - Incremental lifetime models KW - Finite element analysis PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481215 UR - https://www.mdpi.com/2075-4701/9/4/390 DO - https://doi.org/10.3390/met9040390 SN - 2075-4701 VL - 9 IS - 4 SP - 390, 1 EP - 24 PB - mdpi CY - Basel, Switzerland AN - OPUS4-48121 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kern, Simon A1 - Wander, Lukas A1 - Meyer, Klas A1 - Guhl, Svetlana A1 - Gottu Mukkula, A. R. A1 - Holtkamp, M. A1 - Salge, M. A1 - Fleischer, C. A1 - Weber, N. A1 - Engell, S. A1 - Paul, Andrea A1 - Pereira Remelhe, M. A1 - Maiwald, Michael T1 - Flexible automation with compact NMR spectroscopy for continuous production of pharmaceuticals N2 - Modular plants using intensified continuous processes represent an appealing concept for the production of pharmaceuticals. It can improve quality, safety, sustainability, and profitability compared to batch processes; besides, it enables plug-and-produce reconfiguration for fast product changes. To facilitate this flexibility by real-time quality control, we developed a solution that can be adapted quickly to new processes and is based on a compact nuclear magnetic resonance (NMR) spectrometer. The NMR sensor is a benchtop device enhanced to the requirements of automated chemical production including robust evaluation of sensor data. Beyond monitoring the product quality, online NMR data was used in a new iterative optimization approach to maximize the plant profit and served as a reliable reference for the calibration of a near-infrared (NIR) spectrometer. The overall approach was demonstrated on a commercial-scale pilot plant using a metal-organic reaction with pharmaceutical relevance. KW - NMR Spectroscopy KW - NIR Spectroscopy KW - Real-time process monitoring KW - Real-time quality control KW - Continuous processes KW - CONSENS KW - Data Fusion PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-480623 DO - https://doi.org/10.1007/s00216-019-01752-y SN - 1618-2642 SN - 1618-2650 VL - 411 IS - 14 SP - 3037 EP - 3046 PB - Springer Nature CY - Heidelberg AN - OPUS4-48062 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lisec, Jan A1 - Jaeger, Carsten A1 - Rashid, R. A1 - Munir, R. A1 - Zaidi, N. T1 - Cancer cell lipid class homeostasis is altered under nutrient-deprivation but stable under hypoxia N2 - Background: Cancer cells modify the balance between fatty acid (FA) synthesis and uptake under metabolic stress, induced by oxygen/nutrient deprivation. These modifications were shown to alter the levels of individual triglyceride (TG) or phospholipid sub-species. To attain a holistic overview of the lipidomic profiles of cancer cells under stress we performed a broad lipidomic assay, comprising 244 lipids from six major classes. This assay allowed us to perform robust analyses and assess the changes in averages of broader lipid-classes, stratified on the basis of saturation index of their fatty-acyl side chains. Methods: Global lipidomic profiling using Liquid Chromatography-Mass Spectrometry was performed to assess lipidomic profiles of biologically diverse cancer cell lines cultivated under metabolically stressed conditions. Results: Neutral lipid compositions were markedly modified under serum-deprived conditions and, strikingly, the cellular level of triglyceride subspecies decreased with increasing number of double bonds in their fatty acyl chains. In contrast and unexpectedly, no robust changes were observed in lipidomic profiles of hypoxic (2% O2) Cancer cells despite concurrent changes in proliferation rates and metabolic gene expression. Conclusions: Serum-deprivation significantly affects lipidomic profiles of cancer cells. Although, the levels of individual lipid moieties alter under hypoxia (2% O2), the robust averages of broader lipid classes remain unchanged. KW - Tumor metabolism KW - Fatty acid metabolism KW - Lipidomic profile KW - Metabolic stress PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481061 DO - https://doi.org/10.1186/s12885-019-5733-y SN - 1471-2407 VL - 19 SP - 501, 1 EP - 11 PB - Springer Nature AN - OPUS4-48106 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gotor, Raúl A1 - Bell, Jérémy A1 - Rurack, Knut T1 - Tailored fluorescent solvatochromic test strips for quantitative on-site detection of gasoline fuel adulteration N2 - Gasoline adulteration is a frequent problem world-wide, because of the chance of quick, maximized profits. However, addition of cheaper ethanol or hydrocarbons like kerosene does not only result in economic damage but also poses problems for vehicles and the environment. To enable law enforcement forces, customers or enterprises to uncover such a fraudulent activity directly upon suspicion and without the need to organize for sampling and laboratory analysis, we developed a simple strip-based chemical test. Key to the favorable performance was the dedicated materials tailoring, which led to test strips that consisted of a cellulose support coated with silica, passivated with hexamethyldisilazane and functionalized covalently with a molecular probe. The probe fluoresces brightly across a broad solvent polarity range, enabling reliable quantitative measurements and data analysis with a conventional smartphone. The assays showed high reproducibility and accuracy, allowing not only for the detection of gasoline adulteration but also for the on-site monitoring of the quality of commercial E10 gasoline. KW - Gasoline KW - Adulteration KW - Test strips KW - Benzin KW - Teststreifen KW - Fluorescence KW - Cellulose KW - Zellulose KW - Fluoreszenz PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479231 UR - https://pubs.rsc.org/en/content/articlelanding/2019/tc/c8tc04818e DO - https://doi.org/10.1039/C8TC04818E SN - 2050-7526 VL - 7 IS - 8 SP - 2250 EP - 2256 PB - Royal Society of Chemistry CY - London, UK AN - OPUS4-47923 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lisec, Jan A1 - Jaeger, Carsten A1 - Rashid, R. A1 - Munir, R. A1 - Zaidi, N. T1 - Cancer cell lipid class homeostasis is altered under nutrient-deprivation but stable under hypoxia N2 - Background: Cancer cells modify the balance between fatty acid (FA) synthesis and uptake under metabolic stress, induced by oxygen/nutrient deprivation. These modifications were shown to alter the levels of individual triglyceride (TG) or phospholipid sub-species. To attain a holistic overview of the lipidomic profiles of cancer cells under stress we performed a broad lipidomic assay, comprising 244 lipids from six major classes. This assay allowed us to perform robust analyses and assess the changes in averages of broader lipid-classes, stratified on the basis of saturation index of their fatty-acyl side chains. Methods: Global lipidomic profiling using Liquid Chromatography-Mass Spectrometry was performed to assess lipidomic profiles of biologically diverse cancer cell lines cultivated under metabolically stressed conditions. Results: Neutral lipid compositions were markedly modified under serum-deprived conditions and, strikingly, the cellular level of triglyceride subspecies decreased with increasing number of double bonds in their fatty acyl chains. In contrast and unexpectedly, no robust changes were observed in lipidomic profiles of hypoxic (2% O2) cancer cells despite concurrent changes in proliferation rates and metabolic gene expression. Conclusions: Serum-deprivation significantly affects lipidomic profiles of cancer cells. Although, the levels of individual lipid moieties alter under hypoxia (2% O2), the robust averages of broader lipid classes remain unchanged. KW - Tumor metabolism KW - Fatty acid metabolism KW - Lipidomic profile KW - Metabolic stress PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483186 DO - https://doi.org/10.1186/s12885-019-5733-y SN - 1471-2407 VL - 19 SP - 501 PB - Springer Nature CY - Berlin AN - OPUS4-48318 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - El-Khatib, A. H. A1 - Radbruch, H. A1 - Trog, S. A1 - Neumann, B. A1 - Paul, F. A1 - Koch, A. A1 - Linscheid, M. W. A1 - Jakubowski, Norbert A1 - Schellenberger, E. T1 - Gadolinium in human brain sections and colocalization with other elements N2 - Recent recommendations by the Food and Drug Administration1 and the European Medicines Agency2 are to limit the clinical use of linear gadolinium-based contrast agents (GBCAs) due to convincing evidence of deposition in tissues. Macrocyclic GBCA continued to be considered safe, provided that patients have normal renal function. To date, given the low sensitivity of conventional MRI, there has been a debate about the signal increase following the injections of a macrocyclic GBCA. KW - Gadolinium PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471309 DO - https://doi.org/10.1212/NXI.0000000000000515 SN - 2332-7812 VL - 6 IS - 1 SP - e515, 1 EP - 3 PB - American Academy of Neurology AN - OPUS4-47130 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Duewer, D. L. A1 - Murray, J. A. A1 - Wood, L. J. A1 - Wise, S. A. A1 - Hein, Sebastian A1 - Koch, Matthias A1 - Philipp, Rosemarie A1 - Werneburg, Martina A1 - Hackenberg, R. A1 - Polzer, J. A1 - Avila, M. A. A1 - Serrano, V. A1 - Kakoulides, E. A1 - Alexopoulos, C. A1 - Giannikopoulou, P. A1 - Gui, E. M. A1 - Lu, T. A1 - Teo, T. L. A1 - Hua, T. A1 - Dazhou, C. A1 - Chunxin, L. A1 - Changjun, Y. A1 - Hongmei, L. A1 - Nammoonnoy, J. A1 - Sander, L. C. A1 - Lippa, K. A1 - Quinn, L. A1 - Swiegelaar, C. A1 - Fernandes-Whaley, M. A1 - Gören, A. C. A1 - Gökcen, T. T1 - CCQM-K95.1 Low-polarity analytes in a botanical matrix: Polycyclic aromatic hydrocarbons (PAHs) in tea N2 - Extraction, chromatographic separation, and quantification of low-concentration organic compounds in complex matrices are core challenges for reference material producers and providers of calibration services. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2014 the Organic Analysis Working Group (OAWG) initiated CCQM-K95.1 "Low-Polarity Analytes in a Botanical Matrix: Polycyclic Aromatic Hydrocarbons (PAHs) in Tea". This was a follow-on comparison from CCQM-K95 which was completed in 2014. The polycyclic aromatic hydrocarbons (PAHs) benz[a]anthracene (BaA) and benzo[a]pyrene (BaP) are considered priority pollutants by U.S. Environmental Protection Agency and are regulated contaminants in food, pose chromatographic separation challenges, and for which exist well-characterized measurement procedures and standard materials. BaA and BaP in a smoked tea were therefore selected as representative target measurands for CCQM-K95.1. Ten NMIs participated in CCQM-K95.1. The consensus summary mass fractions for the two PAHs are in the range of (50 to 70) ng/g with relative standard deviations of (6 to 10) %. Successful participation in CCQM K95.1 demonstrates the following measurement capabilities in determining mass fraction of organic compounds, with molar mass of 100 g/mol to 500 g/mol and having polarity pKow −2, in a botanical matrix ranging in mass fraction from 10 ng/g to 1000 ng/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, (3) extraction of analytes of interest from the matrix, (4) cleanup and separation of analytes of interest from interfering matrix or extract components, and (5) separation and quantification using gas chromatography or liquid chromatography. KW - Benz[a]anthracene (BaA) KW - Benzo[a]pyrene (BaP) KW - Gas chromatography (GC) KW - Isotope dilution (ID) KW - Liquid chromatography (LC) KW - Mass spectrometry (MS) KW - Polycyclic aromatic hydrocarbon (PAH) KW - Yerba mate tea PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471430 DO - https://doi.org/10.1088/0026-1394/56/1A/08002 SN - 0026-1394 SN - 1681-7575 VL - 56 IS - 1 A SP - 08002, 1 EP - 89 PB - IOP Science AN - OPUS4-47143 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emmerling, Franziska A1 - Stock, Norbert A1 - Tadei, Marco A1 - Demel, Jan A1 - Cabeza, Aurelio A1 - Viviani, Riccardo A1 - Demadis, Konstantinos A1 - Vassaki, Maria T1 - New directions in metal phosphonate and phosphinate chemistry N2 - In September 2018, the First European Workshop on Metal Phosphonates Chemistry brought together some prominent researchers in the field of metal phosphonates and phosphinates with the aim of discussing past and current research efforts and identifying future directions. The scope of this perspective article is to provide a critical overview of the topics discussed during the workshop, which are divided into two main areas: synthesis and characterisation, and applications. In terms of synthetic methods, there has been a push towards cleaner and more efficient approaches. This has led to the introduction of high-throughput synthesis and mechanochemical synthesis. The recent success of metal–organic frameworks has also promoted renewed interest in the synthesis of porous metal phosphonates and phosphinates. Regarding characterisation, the main advances are the development of electron diffraction as a tool for crystal structure determination and the deployment of in situ characterisation techniques, which have allowed for a better understanding of reaction pathways. In terms of applications, metal phosphonates have been found to be suitable materials for several purposes: they have been employed as heterogeneous catalysts for the synthesis of fine chemicals, as solid sorbents for gas separation, notably CO2 capture, as materials for electrochemical devices, such as fuel cells and rechargeable batteries, and as matrices for drug delivery. KW - Metal phosphonates KW - Metal–organic frameworks KW - X-ray and electron diffraction PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484346 DO - https://doi.org/10.3390/cryst9050270 SN - 2073-4352 VL - 9 IS - 5 SP - 270, 1 EP - 36 PB - MDPI AN - OPUS4-48434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - The influence of processing parameters on X‑ray emission during ultra‑short pulse laser machining N2 - During ultra-short laser material processing at high laser pulse repetition rates unwanted X-ray radiation can be generated in a quantity that may constitute a potential risk for health. An adequate X-ray radiation protection requires a thoroughly understanding of the influence of the laser processing parameters on the generation of X-ray radiation. In the present work, the generated X-ray dose during laser machining was investigated in air for varying beam scanning conditions at a pulse duration of 925 fs, a center wavelength of 1030 nm and a laser peak intensity of 2.6 × 10^14 W/cm^2. The X-ray radiation dose and the corresponding spectral X-ray emission were investigated in dependence on the laser’s pulse repetition rate and on the beam scanning speed. The results show a strong dependence of the X-ray emission on these laser processing parameters. KW - Laser-induced X-ray emission KW - Ultrashort laser material interaction KW - Femtosecond laser KW - Radiation protection PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486441 DO - https://doi.org/10.1007/s00339-019-2827-y SN - 0947-8396 SN - 1432-0630 VL - 125 IS - 8 SP - 570, 1 EP - 8 PB - Springer AN - OPUS4-48644 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schürmann, Robin A1 - Ebel, Kenny A1 - Nicolas, C. A1 - Milosavljevic, A. R. A1 - Bald, Ilko T1 - Role of valence band states and plasmonic enhancement in electron-transfer-induced transformation of nitrothiophenol N2 - Hot-electron-induced reactions are more and more recognized as a critical and ubiquitous reaction in heterogeneous catalysis. However, the kinetics of these reactions is still poorly understood, which is also due to the complexity of plasmonic nanostructures. We determined the reaction rates of the hot-electron-mediated reaction of 4-nitrothiophenol (NTP) on gold nanoparticles (AuNPs) using fractal kinetics as a function of the laser wavelength and compared them with the plasmonic enhancement of the system. The reaction rates can be only partially explained by the plasmonic response of the NPs. Hence, synchrotron X-ray photoelectron spectroscopy (XPS) measurements of isolated NTP-capped AuNP clusters have been performed for the first time. In this way, it was possible to determine the work function and the accessible valence band states of the NP systems. The results show that besides the plasmonic enhancement, the reaction rates are strongly influenced by the local density of the available electronic states of the system. KW - Photocatalytic reduction KW - Raman-spectroscopy KW - Hot-electrons KW - Work function KW - Surface KW - Nanaoparticles KW - Scattering KW - Molecule KW - Carriers KW - Layers PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486464 DO - https://doi.org/10.1021/acs.jpclett.9b00848 SN - 1948-7185 VL - 10 IS - 11 SP - 3153 EP - 3158 PB - American Chemical Society CY - Washington, DC AN - OPUS4-48646 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heck, Christian A1 - Kanehira, Y. A1 - Kneipp, Janina A1 - Bald, Ilko T1 - Amorphous Carbon Generation as a Photocatalytic Reaction on DNA-Assembled Gold and Silver Nanostructures N2 - Background signals from in situ-formed amorphous carbon, despite not being fully understood, are known to be a common issue in few-molecule surface-enhanced Raman scattering (SERS). Here, discrete gold and silver nanoparticle aggregates assembled by DNA origami were used to study the conditions for the formation of amorphous carbon during SERS measurements. Gold and silver dimers were exposed to laser light of varied power densities and wavelengths. Amorphous carbon prevalently formed on silver aggregates and at high power densities. Time-resolved measurements enabled us to follow the formation of amorphous carbon. Silver nanolenses consisting of three differently-sized silver nanoparticles were used to follow the generation of amorphous carbon at the single-nanostructure level. This allowed observation of the many sharp peaks that constitute the broad amorphous carbon signal found in ensemble measurements. In conclusion, we highlight strategies to prevent amorphous carbon formation, especially for DNA-assembled SERS substrates. KW - Amorphous carbon KW - DNA origami KW - SERS KW - Nanoparticle dimers KW - Nanolenses PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486484 DO - https://doi.org/10.3390/molecules24122324 SN - 1420-3049 VL - 24 IS - 12 SP - Article Number: 2324-1 EP - 10 PB - MDPI AN - OPUS4-48648 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Steger, Simon A1 - Oesterle, D. A1 - Bretz, S. A1 - Frenzel, L. A1 - Stege, H. A1 - Winkelmeyer, I. A1 - Hahn, Oliver A1 - Geiger, G. T1 - Kandinsky’s fragile art: a multidisciplinary investigation of four early reverse glass paintings (1911–1914) by Wassily Kandinsky N2 - This work highlights the rediscovery of the technique of reverse glass painting by the artists of the “Blaue Reiter” collective in the early 20th-century and focusses particularly on the role of Wassily Kandinsky (1866–1944). Kandinsky created more than 70 reverse paintings on glass and showed several of them in exhibitions together with paintings on canvas and cardboard, implying a coequal importance of these techniques. Four of his early (1911–1914) reverse glass paintings (Auferstehung, Allerheiligen II, Rudern, Apokalyptischer Reiter II) were selected for investigation and their iconography, painting techniques and painting materials were examined. Two paintings were executed on so-called cathedral glass, revealing a “hammered surface”, whereas Kandinsky used a corrugated glass panel for Rudern. A multi-analytical, non-invasive approach [X-ray fluorescence (XRF), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), VIS spectroscopy (VIS), Raman spectroscopy] was taken to identify the pigments and classify the binding media. The results reveal a broad palette of materials. Several pigments like lead white, zinc white, Strontium yellow, Prussian blue, viridian, cadmium yellow, ultramarine blue, cinnabar and carbon black were found in most of the four paintings. The use of the rare synthetic organic pigments PR60 and PB52 is discussed. In two works of art, cadmium carbonate is associated with cadmium yellow. The identification of aluminium foil along with tin foils in Rudern indicates an early use of this material for reverse glass paintings. KW - Reverse glass painting KW - Non-invasive analysis KW - Raman spectroscopy KW - DRIFTS PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-480075 DO - https://doi.org/10.1186/s40494-019-0268-8 VL - 7 IS - 27 SP - 1 EP - 17 PB - Springer AN - OPUS4-48007 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Topolniak, Ievgeniia A1 - Hodoroaba, Vasile-Dan A1 - Pfeifer, Dietmar A1 - Braun, Ulrike A1 - Sturm, Heinz T1 - Boehmite Nanofillers in Epoxy Oligosiloxane Resins: Influencing the Curing Process by Complex Physical and Chemical Interactions N2 - In this work, a novel boehmite (BA)-embedded organic/inorganic nanocomposite coating based on cycloaliphatic epoxy oligosiloxane (CEOS) resin was fabricated applying UV-induced cationic polymerization. The main changes of the material behavior caused by the nanofiller were investigated with regard to its photocuring kinetics, thermal stability, and glass transition. The role of the particle surface was of particular interest, thus, unmodified nanoparticles (HP14) and particles modified with p-toluenesulfonic acid (OS1) were incorporated into a CEOS matrix in the concentration range of 1–10 wt.%. Resulting nanocomposites exhibited improved thermal properties, with the glass transition temperature (Tg) being shifted from 30 °C for unfilled CEOS to 54 °C (2 wt.% HP14) and 73 °C (2 wt.% OS1) for filled CEOS. Additionally, TGA analysis showed increased thermal stability of samples filled with nanoparticles. An attractive interaction between boehmite and CEOS matrix influenced the curing. Real-time infrared spectroscopy (RT-IR) experiments demonstrated that the epoxide conversion rate of nanocomposites was slightly increased compared to neat resin. The beneficial role of the BA can be explained by the participation of hydroxyl groups at the particle surface in photopolymerization processes and by the complementary contribution of p-toluenesulfonic acid surface modifier and water molecules introduced into the system with nanoparticles. KW - Real-time infrared spectroscopy KW - Boehmite KW - Nanocomposite KW - Cationic photocuring KW - Cycloaliphatic epoxy oligosiloxane KW - Epoxy conversion degree PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479628 DO - https://doi.org/10.3390/ma12091513 VL - 12 IS - 9 SP - 1513 PB - MDPI AN - OPUS4-47962 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kalbe, Ute A1 - Lehnik-Habrink, Petra A1 - Bandow, Nicole A1 - Sauer, Andreas T1 - Validation of European horizontal methods for the analysis of PAH, PCB and dioxins in sludge, treated biowaste and soil N2 - Draft standards for the determination of organic pollutants in the solid matter of environmental matrices such as sludge, treated biowaste and soil have been basically developed in the framework of the European standardization project HORIZONTAL. A research project financed by the German Federal Environment Agency was initiated to finalize some of these CEN standard drafts, since fully validated standard procedures are crucial for the evaluation of their reliability in the context of implementation in legislation on environmental health. Approach: Appropriate test materials (< 2mm particle size) were prepared and homogenized from contaminated soils, sludge and treated biowaste containing polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), dioxins, furans and dioxin-like-PCB and served, along with reference solutions, as the basis for international interlaboratory comparisons. Performance data of three analytical standard procedures were obtained by the statistical evaluation of results received from 11 to 29 participants per test material. Results: The overall variation coefficients of reproducibility (between-lab standard deviations) for the sum parameters were roughly between 10 and 35 %. The variation coefficients of repeatability (within-lab standard deviations) range between 3 % and 8 % and show no trend considering the substance groups or matrices. The highest coefficients of reproducibility were found for the analysis of PAHs, which were between 26 and 35 %, depending on the matrix, whereas 7-17 % reproducibility was observed for toxicity equivalents (TEQ) comprising dioxins, furans and dl-PCB. Conclusions: Overall, the results confirm that the procedures described in the Technical Specifications are fit for purpose for all three matrices and that the feasibility of the HORIZONTAL approach, to cover several matrices with one standard per analyte, was thereby proven. KW - Standardization KW - Analytical methods KW - Organic contaminants KW - Validation trial KW - Interlaboratory comparison PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479914 DO - https://doi.org/10.1186/s12302-019-0211-3 SN - 2190-4715 VL - 31 SP - 29, 1 EP - 10 PB - Springer CY - Berlin, Heidelberg AN - OPUS4-47991 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Q. A1 - Zheng, M. A1 - Huang, Y. A1 - Kunte, Hans-Jörg A1 - Wang, X. A1 - Liu, Y. A1 - Zheng, C. T1 - Long term corrosion estimation of carbon steel, titanium and its alloy in backfill material of compacted bentonite for nuclear waste repository N2 - The container of high-level radioactive waste (HLRW) being in deep geological disposal, the backfill material is needed to serve as the second defense for HLRW and the highly compacted bentonite is generally selected. As the time goes, the underground water will infiltrate the backfill, causing the corrosion of materials for the building of containers in the formed electrolyte. Carbon steel, titanium and its alloy are the potential candidate materials for the fabrication of HLRW containers. The current investigation aims at assessing the safety of HLRW container in deep geological disposal for hundreds of thousands of years and facilitating the material selection for future Container fabrication by estimating their corrosion behavior in compacted bentonite with a series of moisture content at different temperatures through electrochemical methods including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PC) measurements. The corrosion rates were estimated for a carbon steel, a pure titanium and a titanium alloy in compacted Gaomiaozi Bentonite infiltrated with simulated underground water in Beishan area of China over an expected disposal period up to 106 years respectively, showing that titanium and its alloy are more reliable materials for building HLRW containers than carbon steel. KW - Issues KW - Disposal KW - Performance KW - Moisture KW - Lifetime KW - Water KW - Model PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492413 DO - https://doi.org/10.1038/s41598-019-39751-9 SN - 2045-2322 VL - 9 SP - 3195 PB - Nature Publishing Group AN - OPUS4-49241 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brüngel, R. A1 - Rückert, J. A1 - Wohlleben, W. A1 - Babick, F. A1 - Ghanem, A. A1 - Gaillard, C. A1 - Mech, A. A1 - Rauscher, H. A1 - Hodoroaba, Vasile-Dan A1 - Weigel, S. A1 - Friedrich, C. M. T1 - NanoDefiner e-Tool: An Implemented Decision Support Framework for Nanomaterial Identification N2 - The European Commission’s recommendation on the definition of nanomaterial (2011/696/EU) established an applicable standard for material categorization. However, manufacturers face regulatory challenges during registration of their products. Reliable categorization is difficult and requires considerable expertise in existing measurement techniques (MTs). Additionally, organizational complexity is increased as different authorities’ registration processes require distinct reporting. The NanoDefine project tackled these obstacles by providing the NanoDefiner e-tool: A decision support expert system for nanomaterial identification in a regulatory context. It providesMT recommendations for categorization of specific materials using a tiered approach (screening/confirmatory), and was constructed with experts from academia and industry to be extensible, interoperable, and adaptable for forthcoming revisions of the nanomaterial definition. An implemented MT-driven material categorization scheme allows detailed description. Its guided workflow is suitable for a variety of user groups. Direct feedback and explanation enable transparent decisions. Expert knowledge is Held in a knowledge base for representation of MT performance criteria and physicochemical particle type properties. Continuous revision ensured data quality and validity. Recommendations were validated by independent case studies on industry-relevant particulate materials. Besides supporting material identification and registration, the free and open-source e-tool may serve as template for other expert systems within the nanoscience domain. KW - EC nanomaterial definition KW - Decision support KW - Expert system KW - Nanomaterial KW - Nanoparticles PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492449 DO - https://doi.org/10.3390/ma12193247 VL - 12 IS - 19 SP - 3247 PB - MDPI CY - Basel, CH AN - OPUS4-49244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reimann, C. A1 - Kaufmann, Jan Ole A1 - Adams, L. C. A1 - Onthank, D. C. A1 - Thöne-Reineke, C. A1 - Robinson, S. P. A1 - Hamm, B. A1 - Botnar, R. M. A1 - Makowski, M. R. T1 - Dual-probe molecular MRI for the in vivo characterization of atherosclerosis in a mouse model: Simultaneous assessment of plaque inflammation and extracellular-matrix remodeling N2 - Molecular MRI is a promising in-vivo modality to detect and quantify morphological and molecular vessel-wall changes in atherosclerosis. The combination of different molecular biomarkers may improve the risk stratification of patients. This study aimed to investigate the feasibility of simultaneous visualization and quantification of plaque-burden and inflammatory activity by dual-probe molecular MRI in a mouse-model of progressive atherosclerosis and in response-to-therapy. Homozygous apolipoprotein E knockout mice (ApoE−/−) were fed a high-fat-diet (HFD) for up to four-months prior to MRI of the brachiocephalic-artery. To assess response-to-therapy, a statin was administered for the same duration. MR imaging was performed before and after administration of an elastin-specific gadolinium-based and a macrophage-specific iron-oxide-based probe. Following in-vivo MRI, samples were analyzed using histology, immunohistochemistry, inductively-coupled-mass-spectrometry and laser-inductively-coupled-mass-spectrometry. In atherosclerotic-plaques, intraplaque expression of elastic-fibers and inflammatory activity were not directly linked. While the elastin-specific probe demonstrated the highest accumulation in advanced atherosclerotic-plaques after four-months of HFD, the iron-oxide-based probe showed highest accumulation in early atherosclerotic-plaques after two-months of HFD. In-vivo measurements for the elastin and iron-oxide-probe were in good agreement with ex-vivo histopathology (Elastica-van-Giesson stain: y = 298.2 + 5.8, R2 = 0.83, p < 0.05; Perls‘ Prussian-blue-stain: y = 834.1 + 0.67, R2 = 0.88, p < 0.05). Contrast-to-noise-ratio (CNR) measurements of the elastin probe were in good agreement with ICP-MS (y = 0.11x-11.3, R² = 0.73, p < 0.05). Late stage atherosclerotic-plaques displayed the strongest increase in both CNR and gadolinium concentration (p < 0.05). The gadolinium probe did not affect the visualization of the iron-oxide-probe and vice versa. This study demonstrates the feasibility of simultaneous assessment of plaque-burden and inflammatory activity by dual-probe molecular MRI of progressive atherosclerosis. The in-vivo detection and quantification of different MR biomarkers in a single scan could be useful to improve characterization of atherosclerotic-lesions. KW - In-vivo KW - Molecular MRI PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492514 DO - https://doi.org/10.1038/s41598-019-50100-8 VL - 9 IS - 1 SP - Article number: 13827 PB - Nature AN - OPUS4-49251 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fletcher, D. C. A1 - Hunter, R. A1 - Xia, W. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Blackburn, E. A1 - Kulak, A. A1 - Xin, H. A1 - Schnepp, Z. T1 - Scalable synthesis of dispersible iron carbide (Fe3C) nanoparticles by ‘nanocasting’ N2 - Metal carbides have shown great promise in a wide range of applications due to their unique catalytic, electrocatalytic and magnetic properties. However, the scalable production of dispersible metal carbide nanoparticles remains a challenge. Here, we report a simple and scalable route to dispersible iron carbide (Fe3C) nanoparticles. This uses MgO nanoparticles as a removable ‘cast’ to synthesize Fe3C nanoparticles from Prussian blue (KFeIII[FeII(CN)6]). Electron tomography demonstrates how nanoparticles of the MgO cast encase the Fe3C nanoparticles to prevent sintering and agglomeration during the high-temperature synthesis. The MgO cast is readily removed with ethylenediaminetetraacetic acid (EDTA) to generate Fe3C nanoparticles that can be used to produce a colloidal ferrofluid or dispersed on a support material. KW - Small-angle scattering KW - SAXS KW - Metal carbides KW - Nanoparticles KW - Nanocasting PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486295 DO - https://doi.org/10.1039/C9TA06876G SN - 2050-7488 SN - 2050-7496 VL - 7 IS - 33 SP - 19506 EP - 19512 PB - Royal Society of Chemistry (RSC) AN - OPUS4-48629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Geißler, Daniel A1 - Wegmann, Marc A1 - Jochum, T. A1 - Somma, V. A1 - Sowa, M. A1 - Scholz, J. A1 - Fröhlich, E. A1 - Hoffmann, Katrin A1 - Niehaus, J. A1 - Roggenbuck, D. A1 - Resch-Genger, Ute T1 - An automatable platform for genotoxicity testing of nanomaterials based on the fluorometric γ-H2AX assay reveals no genotoxicity of properly surface-shielded cadmium-based quantum dots N2 - The large number of nanomaterial-based applications emerging in the materials and life sciences and the foreseeable increasing use of these materials require methods that evaluate and characterize the toxic potential of these nanomaterials to keep safety risks to people and environment as low as possible. As nanomaterial toxicity is influenced by a variety of parameters like size, shape, chemical composition, and surface chemistry, high throughput screening (HTS) platforms are recommended for assessing cytotoxicity. Such platforms are not yet available for genotoxicity testing. Here, we present first results obtained for application-relevant nanomaterials using an automatable genotoxicity platform that relies on the quantification of the phosphorylated histone H2AX (γ-H2AX) for detecting DNA double strand breaks (DSBs) and the automated microscope system AKLIDES® for measuring integral fluorescence intensities at different excitation wavelengths. This platform is used to test the genotoxic potential of 30 nm-sized citrate-stabilized gold nanoparticles (Au-NPs) as well as micellar encapsulated iron oxide nanoparticles (FeOx-NPs) and different cadmium (Cd)-based semiconductor quantum dots (QDs), thereby also searching for positive and negative controls as reference materials. In addition, the influence of the QD shell composition on the genotoxic potential of these Cd-based QDs was studied, using CdSe cores as well as CdSe/CdS core/shell and CdSe/CdS/ZnS core/shell/shell QDs. Our results clearly revealed the genotoxicity of the Au-NPs and its absence in the FeOx-NPs. The genotoxicity of the Cd-QDs correlates with the shielding of their Cd-containing core, with the core/shell/shell architecture preventing genotoxicity risks. The fact that none of these nanomaterials showed cytotoxicity at the chosen particle concentrations in a conventional cell viability assay underlines the importance of genotoxicity studies to assess the hazardous potential of nanomaterials. KW - Nanomaterial KW - Genotoxicity testing KW - γ-H2AX assay KW - Quantum dot PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486318 DO - https://doi.org/10.1039/C9NR01021A SN - 2040-3372 SN - 2040-3364 VL - 11 IS - 28 SP - 13458 EP - 13468 PB - The Royal Society of Chemistry AN - OPUS4-48631 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Pourmand, P. A1 - Wolff, Dietmar A1 - Hedenqvist, M. T1 - Analysis of O-ring seal failure under static conditions and determination of end-of-lifetime criterion N2 - Determining a suitable and reliable end-of-lifetime criterion for O-ring seals is an important issue for long-term seal applications. Therefore, seal failure of ethylene propylene diene rubber (EPDM) and hydrogenated nitrile butadiene rubber (HNBR) O-rings aged in the compressed state at 125 °C and at 150 °C for up to 1.5 years was analyzed and investigated under static conditions, using both non-lubricated and lubricated seals. Changes of the material properties were analyzed with dynamic-mechanical analysis and permeability experiments. Indenter modulus measurements were used to investigate DLO effects. It became clear that O-rings can remain leak-tight under static conditions even when material properties have already degraded considerably, especially when adhesion effects are encountered. As a feasible and reliable end-of-lifetime criterion for O-ring seals under static conditions should include a safety margin for slight dimensional changes, a modified leakage test involving a small and rapid partial decompression of the seal was introduced that enabled determining a more realistic but still conservative end-of-lifetime criterion for an EPDM seal. KW - EPDM KW - HNBR KW - Seal failure KW - Leak-tightness KW - DLO KW - Oxygen permability KW - DMA KW - Indenter modulus PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486125 DO - https://doi.org/10.3390/polym11081251 SN - 2073-4360 VL - 11 IS - 8 SP - 1251, 1 EP - 19 PB - MDPI CY - Basel, CH AN - OPUS4-48612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Battig, Alexander A1 - Markwart, J. C. A1 - Wurm, F. R. A1 - Schartel, Bernhard T1 - Hyperbranched phosphorus flame retardants: multifunctional additives for epoxy resins N2 - We successfully synthesized multifunctional P-based hyperbranched polymeric flame retardants (hb-FRs) with varying oxygen-to-nitrogen (O : N) content and characterized them via 1H and 31P NMR and GPC. Their miscibility in epoxy resins (EP) and impact on glass-transition temperatures (Tg) were determined via differential scanning calorimetry (DSC). Using thermogravimetric and evolved gas Analysis (TGA, TG-FTIR), pyrolysis gas chromatography/mass spectrometry (Py-GC-MS), hot stage FTIR, flammability tests UL-94 and LOI, fire testing via cone calorimetry, residue analysis via scanning electron microscopy (SEM) and elemental analysis, detailed decomposition mechanisms and modes of action are proposed. hb-polymeric FRs have improved miscibility and thermal stability, leading to high FR performance even at low loadings. Polymeric, complex FRs increase flame retardancy, mitigate negative effects of low molecular weight variants, and can compete with commercial aromatic FRs. The results illustrate the role played by the chemical structure in flame retardancy and highlight the potential of hb-FRs as multifunctional additives. KW - Flame retardant KW - Hyperbranched PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486589 DO - https://doi.org/10.1039/c9py00737g SN - 1759-9962 SN - 1759-9954 VL - 10 IS - 31 SP - 4346 EP - 4358 PB - RSC AN - OPUS4-48658 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blaeß, Carsten A1 - Müller, Ralf A1 - Poologasundarampilai, G. A1 - Brauer, D. S. T1 - Sintering and concomitant crystallization of bioactive glasses N2 - The sintering of bioactive glasses allows for the preparation of complex structures, such as three‐dimensional porous scaffolds. Such 3D constructs are particularly interesting for clinical applications of bioactive glasses in bone regeneration, as the scaffolds can act as a guide for in‐growing bone cells, allowing for good Integration with existing and newly formed tissue while the scaffold slowly degrades. Owing to the pronounced tendency of many bioactive glasses to crystallize upon heat treatment, 3D scaffolds have not been much exploited commercially. Here, we investigate the influence of crystallization on the sintering behavior of several bioactive glasses. In a series of mixed‐alkali glasses an increased CaO/alkali metal oxide Ratio improved sintering compared to Bioglass 45S5, where dense sintering was inhibited. Addition of small amounts of calcium fluoride helped to keep melting and sintering temperatures low. Unlike glass 13‐93, these new glasses crystallized during sintering but this did not prevent densification. Variation in bioactive glass particle size allowed for fine‐tuning the microporosity resulting from the sintering process. KW - Bioactive glass KW - Crystallization KW - Scaffolds KW - Sintering PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485458 DO - https://doi.org/10.1111/ijag.13477 SN - 2041-1286 VL - 10 IS - 4 SP - 449 EP - 462 PB - Wiley AN - OPUS4-48545 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -