TY - JOUR A1 - Yildirim, Arda A1 - Krause, Christina A1 - Zorn, R. A1 - Lohstroh, W. A1 - Schneider, G. J. A1 - Zamponi, M. A1 - Holerer, O. A1 - Frick, B. A1 - Schönhals, Andreas T1 - Complex molecular dynamics of a symmetric model discotic liquid crystal revealed by broadband dielectric, thermal and neutron spectroscopy N2 - The molecular dynamics of the triphenylene-based discotic liquid crystal HAT6 is investigated by broadband dielectric spectroscopy, advanced dynamical calorimetry and neutron scattering. Differential scanning calorimetry in combination with X-ray scattering reveals that HAT6 has a plastic crystalline phase at low temperatures, a hexagonally ordered liquid crystalline phase at higher temperatures and undergoes a clearing transition at even higher temperatures. The dielectric spectra show several relaxation processes: a localized gamma-relaxation a lower temperature and a so called alpha-2-relaxation at higher temperatures. The relaxation rates of the alpha-2-relaxation have a complex temperature dependence and bear similarities to a dynamic glass transition. The relaxation rates estimated by hyper DSC, Fast Scanning calorimetry and AC Chip calorimetry have a different temperature dependence than the dielectric alpha-2-relaxation and follows the VFT-behavior characteristic for glassy dynamics. Therefore, this process is called alpha-1-relaxation. Its relaxation rates show a similarity with that of polyethylene. For this reason, the alpha-1-relaxation is assigned to the dynamic glass transition of the alkyl chains in the intercolumnar space. Moreover, this process is not observed by dielectric spectroscopy which supports its assignment. The alpha-2-relaxation was assigned to small scale translatorial and/or small angle fluctuations of the cores. The neutron scattering data reveal two relaxation processes. The process observed at shorter relaxation times is assigned to the methyl group rotation. The second relaxation process at longer time scales agree in the temperature dependence of its relaxation rates with that of the dielectric gamma-relaxation. KW - Discotic Liquid Crystals PY - 2020 DO - https://doi.org/10.1039/c9sm02487e VL - 16 IS - 8 SP - 2005 EP - 2016 PB - Royal Chemical Society AN - OPUS4-50466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eckel, S. A1 - Zscherpel, Uwe A1 - Huthwaite, P. A1 - Paul, N. A1 - Schumm, A. T1 - Radiographic film system classification and noise characterisation by a camera-based digitisation procedure N2 - Extracting statistical characteristics from radiographic films is vital for film system classification and contrast sensitivity evaluation and serves as a basis for film noise simulation. A new method for digitising radiographic films in order to extract these characteristics is presented. The method consists of a camera-based setup and image processing procedure to digitise films. Correct optical density values and granularity can be extracted from the digitised images, which are equal to results obtained by standardised measurement procedures. Specific statistical characteristics of film noise are theoretically derived and subsequently verified by the obtained data, including characteristics such as Gaussianity and spatial spectral characteristics of the optical density fluctuations. It is shown that the presented method correctly measures the granularity of film noise and can therefore replace time-consuming microdensitometer measurements traditionally required for film system classifications. Additionally, the inherent unsharpness of film systems was investigated and compared with literature data. This comparison serves as another validation approach of the presented method. KW - Radiography KW - Image processing KW - Film noise KW - Film system classification KW - Digitisation PY - 2020 DO - https://doi.org/10.1016/j.ndteint.2020.102241 SN - 0963-8695 VL - 111 IS - 4 SP - 102241 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-50517 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eckel, S. A1 - Huthwaite, P. A1 - Zscherpel, Uwe A1 - Schumm, A. A1 - Paul, N. T1 - Realistic film noise generation based on experimental noise spectra N2 - Generating 2D noise with local, space-varying spectral characteristics is vital where random noise fields with spatially heterogeneous statistical properties are observed and need to be simulated. A realistic, non-stationary noise generator relying on experimental data is presented. That generator is desired in areas such as photography and radiography. For example, before performing actual X-ray imaging in practice, output images are simulated to assess and improve setups. For that purpose, realistic film noise modelling is crucial because noise downgrades the detectability of visual signals. The presented film noise synthesiser improves the realism and value of radiographic simulations significantly, allowing more realistic assessments of radiographic test setups. The method respects space-varying spectral characteristics and probability distributions, locally simulating noise with realistic granularity and contrast. The benefits of this approach are to respect the correlation between noise and image as well as internal correlation, the fast generation of any number of unique noise samples, the exploitation of real experimental data, and its statistical non-stationarity. The combination of these benefits is not available in existing work. Validation of the new technique was undertaken in the field of industrial radiography. While applied to that field here, the technique is general and can also be utilised in any other field where the generation of 2D noise with local, space-varying statistical properties is necessary. KW - Nondestructive testing KW - Image quality KW - Noise simulation KW - Radiography PY - 2020 DO - https://doi.org/10.1109/TIP.2019.2955284 SN - 1057-7149 VL - 29 SP - 2987 EP - 2998 PB - IEEE Xplore CY - Washington, D.C. AN - OPUS4-50518 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schulze-Makuch, D. A1 - Haque, S. A1 - Beckles, D. A1 - Schmitt-Kopplin, P. A1 - Harir, M. A1 - Schneider, Beate A1 - Stumpp, C. A1 - Wagner, D. T1 - A chemical and microbial characterization of selected mud volcanoes in Trinidad reveals pathogens introduced by surface water and rain water N2 - Terrestrial mud volcanoes are unique structures driven by tectonic pressure and fluids from the deep subsurface. These structures are mainly found in active tectonic zones, such as the area near the Los Bajos Fault in Trinidad. Here we report a chemical and microbiological characterization of three mud volcanoes, which included analyses of multiple liquid and solid samples from the mud volcanoes. Our study confirms previous suggestions that at least some of the mud volcano fluids are a mixture of deeper salt-rich water and surficial/precipitation water. No apparent water quality differences were found between sampling sites north and south of a major geological fault line. Microbiological analyses revealed diverse communities, both aerobic and anaerobic, including sulfate reducers, methanogens, carbon dioxide fixing and denitrifying bacteria. Several identified species were halophilic and likely derived from the deeper salt-rich subsurface water, while we also cultivated pathogenic species from the Vibrionaceae, Enterobacteriaceae, Shewanellaceae, and Clostridiaceae. These microorganisms were likely introduced into the mud volcano fluids both from surface water or shallow ground-water, and perhaps to a more minor degree by rain water. The identified pathogens are a major health concern that needs to be addressed. KW - Water stable isotope analysis KW - Mud volcanoe fluids KW - Metabolomics PY - 2020 DO - https://doi.org/10.1016/j.scitotenv.2019.136087 VL - 707 SP - 136087 PB - Elsevier B.V. AN - OPUS4-50499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Galbacs, G. A1 - Keri, A. A1 - Kalomista, I. A1 - Kovacs-Szeles, E. A1 - Gornushkin, Igor B. T1 - Deuterium analysis by inductively coupled plasma mass spectrometry using polyatomic species: An experimental study supported by plasma chemistry modeling N2 - based on the use of the signal from hydrogen-containing polyatomic ions formed in the inductively coupled plasma. Prior to analytical experiments, a theoretical study was performed to assess the concentration of polyatomic species present in an equilibrium Ar-O-D-H plasma, as a function of temperature and stoichiometric composition. It was established that the highest sensitivity and linearity measurement of D concentration in a wide range can be achieved by monitoring the ions of D2 and ArD, at masses 4 and 42, respectively. Results of the calculations are in good agreement with the experiments. Signal stability, spectral interferences, as well as the effect of plasma parameters were also assessed. Under optimized conditions, the limit of detection (LOD) was found to be 3 ppm atom fraction for deuterium when measured as ArD (in calcium and potassium free water), or 78 ppm when measured as D2. The achieved LOD values and the 4 to 5 orders of magnitude dynamic range easily allow the measurement of deuterium concentrations at around or above the natural level, up to nearly 100% (or 1 Mio ppm) in a standard quadrupole ICP-MS instrument. An even better performance is expected from the method in high resolution ICP-MS instruments equipped with low dead volume sample introduction systems KW - ICP MS KW - Deuterium KW - Deuterium enriched water PY - 2020 DO - https://doi.org/10.1016/j.aca.2020.01.011 VL - 1104 SP - 28 EP - 37 PB - Elsevier B.V. AN - OPUS4-50777 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tscheuschner, Georg A1 - Schwaar, Timm A1 - Weller, Michael G. T1 - Fast Confirmation of Antibody Identity by MALDI-TOF MS Fingerprints N2 - Thousands of antibodies for diagnostic and other analytical purposes are on the market. However, it is often difficult to identify duplicates, reagent changes, and to assign the correct original publications to an antibody. This slows down scientific progress and might even be a cause of irreproducible research and a waste of resources. Recently, activities were started to suggest the sole use of recombinant antibodies in combination with the open communication of their sequence. In this case, such uncertainties should be eliminated. Unfortunately, this approach seems to be rather a long-term vision since the development and manufacturing of recombinant antibodies remain quite expensive in the foreseeable future. Nearly all commercial antibody suppliers also may be reluctant to publish the sequence of their antibodies, since they fear counterfeiting. De novo sequencing of antibodies is also not feasible today for a reagent user without access to the hybridoma clone. Nevertheless, it seems to be crucial for any scientist to have the opportunity to identify an antibody undoubtedly to guarantee the traceability of any research activity using antibodies from a third party as a tool. For this purpose, we developed a method for the identification of antibodies based on a MALDI-TOF MS fingerprint. To circumvent lengthy denaturation, reduction, alkylation, and enzymatic digestion steps, the fragmentation was performed with a simple formic acid hydrolysis step. Eighty-nine unknown monoclonal antibodies were used for this study to examine the feasibility of this approach. Although the molecular assignment of peaks was rarely possible, antibodies could be easily recognized in a blinded test, simply from their mass-spectral fingerprint. A general protocol is given, which could be used without any optimization to generate fingerprints for a database. We want to propose that, in most scientific projects relying critically on antibody reagents, such a fingerprint should be established to prove and document the identity of the used antibodies, as well as to assign a specific reagent to a datasheet of a commercial supplier, public database record, or antibody ID. KW - Reproducibility KW - Quality Control KW - Traceability KW - Diagnostics KW - Hybridoma KW - Monoclonal Antibody KW - Recombinant Antibody PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506611 DO - https://doi.org/10.3390/antib9020008 SN - 2073-4468 VL - 9 IS - 2 SP - 1 EP - 17 PB - MDPI CY - Basel AN - OPUS4-50661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baláž, M. A1 - Tešinský, M. A1 - Marquardt, Julien A1 - Škrobian, M. A1 - Daneu, N. A1 - Rajňák, M. A1 - Baláž, P. T1 - Synthesis of copper nanoparticles from refractory sulfides using a semi-industrial mechanochemical approach N2 - The large-scale mechanochemical reduction of binary sulfides chalcocite (Cu2S) and covellite (CuS) by elemental iron was investigated in this work. The reduction of Cu2S was almost complete after 360 min of milling, whereas in the case of CuS, a significant amount of non-reacted elemental iron could still be identified after 480 min. Upon application of more effective laboratory-scale planetary ball milling, it was possible to reach almost complete reduction of CuS. Longer milling leads to the formation of ternary sulfides and oxidation product, namely cuprospinel CuFe2O4. The rate constant calculated from the magnetometry measurements using a diffusion model for Cu2S and CuS reduction by iron in a large-scale mill is 0.056 min−0.5 and 0.037 min−0.5, respectively, whereas for the CuS reduction in a laboratory-scale mill, it is 0.1477 min−1. The nanocrystalline character of the samples was confirmed by TEM and XRD, as the produced Cu exhibited sizes up to 16 nm in all cases. The process can be easily scaled up and thus copper can be obtained much easier from refractory minerals than in traditional metallurgical approaches. KW - Mechanochemistry KW - Copper sulfides KW - Copper nanoparticles KW - Magnetometry KW - Oxidation PY - 2020 DO - https://doi.org/10.1016/j.apt.2019.11.032 VL - 31 IS - 2 SP - 782 EP - 791 PB - Elsevier B.V. AN - OPUS4-50665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brinker, U. A1 - Bērziņš, V. A1 - Ceriņa, A. A1 - Gerhards, G. A1 - Kalniņš, M. A1 - Schmölcke, U. A1 - Meinel, Dietmar A1 - Luebke, H. T1 - Two burials in a unique freshwater shell midden: insights into transformations of Stone Age hunter-fisher daily life in Latvia N2 - The Stone Age site Riņņukalns, Latvia, is the only well-stratified shell midden in the Eastern Baltic. In this paper, we present new interdisciplinary results concerning its dating, stratigraphy, features, and finds to shed light on the daily life of a fisher population prior to the introduction of domesticated animals. The undisturbed part of the midden consists of alternating layers of unburnt mussel shell, burnt mussel shell and fish bone, containing artefacts, some mammal and bird bones, and human burials. Two of them, an adult man and a baby, are discovered recently and date to the calibration plateau between 3350 and 3100 cal BC, and to the later 4th millennium, respectively. Stable isotopes suggest a diet based heavily on freshwater fish, and this is supported not only by ten thousands of identified fish remains, but also by a fish bone concentration nearby the skull of the man, which is interpreted as remain of a grave gift (possible fish soup). Of special interest are the baby’s stable isotope values. It shows that the mother’s diet was atypical (perhaps because she was non-local), and/or that dietary stress during pregnancy increased fractionation between the mother’s diet and her bloodstream KW - Baltic Stone Age KW - Palaeoanthropology PY - 2020 DO - https://doi.org/10.1007/s12520-020-01049-7 VL - 12 IS - 5 SP - Article number: 97 PB - Springer-Verlag GmbH CY - Germany AN - OPUS4-50653 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aratsu, K. A1 - Takeya, R. A1 - Pauw, Brian Richard A1 - Hollamby, M.J. A1 - Kitamoto, Y. A1 - Shimizu, N. A1 - Takagi, H. A1 - Haruki, R. A1 - Adachi, S. A1 - Yagai, S. T1 - Supramolecular copolymerization driven by integrative self-sorting of hydrogen-bonded rosettes N2 - Molecular recognition to preorganize noncovalently polymerizable supramolecular complexes is a characteristic process of natural supramolecular polymers, and such recognition processes allow for dynamic self-alteration, yielding complex polymer systems with extraordinarily high efficiency in their targeted function. We herein show an example of such molecular recognition-controlled kinetic assembly/disassembly processes within artificial supramolecular polymer systems using six-membered hydrogen-bonded supramolecular complexes (rosettes). Electron-rich and poor monomers are prepared that kinetically coassemble through a temperature-controlled protocol into amorphous coaggregates comprising a diverse mixture of rosettes. Over days, the electrostatic interaction between two monomers induces an integrative self-sorting of rosettes. While the electron-rich monomer inherently forms toroidal homopolymers, the additional electrostatic interaction that can also guide rosette association allows helicoidal growth of supramolecular copolymers that are comprised of an alternating array of two monomers. Upon heating, the helicoidal copolymers undergo a catastrophic transition into amorphous coaggregates via entropy-driven randomization of the monomers in the rosette. KW - Self-assembly KW - Coaggregation KW - Scattering KW - Simulation KW - AFM PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506555 DO - https://doi.org/10.1038/s41467-020-15422-6 VL - 11 IS - 1 SP - Article number: 1623 PB - Springer Nature AN - OPUS4-50655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sachse, René A1 - Bernsmeier, D. A1 - Schmack, R. A1 - Häusler, I. A1 - Hertwig, Andreas A1 - Kraffert, K. A1 - Nissen, J. A1 - Kraehnert, R. T1 - Colloidal bimetallic platinum–ruthenium nanoparticles in ordered mesoporous carbon films as highly active electrocatalysts for the hydrogen evolution reaction N2 - Hydrogen features a very high specific energy density and is therefore a promising candidate for clean fuel from renewable resources. Water electrolysis can convert electrical energy into storable and transportable hydrogen gas. Under acidic conditions, platinum is the most active and stable monometallic catalyst for the hydrogen evolution reaction (HER). Yet, platinum is rare and needs to be used efficiently. Here, we report a synthesis concept for colloidal bimetallic platinum–ruthenium and rhodium–ruthenium nanoparticles (PtRuNP, RhRuNP) and their incorporation into ordered mesoporous carbon (OMC) films. The films exhibit high surface area, good electrical conductivity and well-dispersed nanoparticles inside the mesopores. The nanoparticles retain their size, crystallinity and composition during carbonization. In the hydrogen evolution reaction (HER), PtRuNP/OMC catalyst films show up to five times higher activity per Pt than Pt/C/Nafion® and PtRu/C/Nafion® reference catalysts. KW - Ordered mesoporous carbon KW - Bimetallic noble metal nanoparticles KW - Platinum-ruthenium colloid KW - Electrolysis KW - Hydrogen evolution reaction PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506868 DO - https://doi.org/10.1039/C9CY02285F SN - 2044-4753 VL - 10 IS - 7 SP - 2057 EP - 2068 PB - Royal Society of Chemistry AN - OPUS4-50686 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -