TY - JOUR A1 - Hussels, Maria-Teresa A1 - Chruscicki, Sebastian A1 - Arndt, Detlef A1 - Scheider, Swen A1 - Prager, Jens A1 - Homann, Tobias A1 - Habib, Abdel Karim T1 - Localization of transient events threatening pipeline integrity by fiber-optic distributed acoustic sensing N2 - Pipe integrity is a central concern regarding technical safety, availability, and environmental compliance of industrial plants and pipelines. A condition monitoring system that detects and localizes threats in pipes prior to occurrence of actual structural failure, e.g., leakages, especially needs to target transient events such as impacts on the pipe wall or pressure waves travelling through the medium. In the present work, it is shown that fiber-optic distributed acoustic sensing (DAS) in conjunction with a suitable application geometry of the optical fiber sensor allows to track propagating acoustic waves in the pipeline wall on a fast time-scale. Therefore, short impacts on the pipe may be localized with high fidelity. Moreover, different acoustic modes are identified, and their respective group velocities are in good agreement with theoretical predications. In another set of experiments modeling realistic damage scenarios, we demonstrate that pressure waves following explosions of different gas mixtures in pipes can be observed. Velocities are verified by local piezoelectric pressure transducers. Due to the fully distributed nature of the fiber-optic sensing system, it is possible to record accelerated motions in detail. Therefore, in addition to detection and localization of threatening events for infrastructure monitoring, DAS may provide a powerful tool to study the development of gas explosions in pipes, e.g., investigation of deflagration-to-detonation-transitions (DDT). KW - Distributed acoustic sensing (DAS) KW - Distributed vibrations sensing (DVS) KW - Fiber-optic sensing KW - Condition monitoring KW - Pipeline integrity KW - Gas explosion PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488555 DO - https://doi.org/10.3390/s19153322 SN - 1424-8220 VL - 19 IS - 15 SP - 3322, 1 EP - 20 PB - MDPI CY - Basel, CH AN - OPUS4-48855 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Provis, J. L. A1 - Arbi, K. A1 - Bernal, S. A. A1 - Bondar, D. A1 - Buchwald, A. A1 - Castel, A. A1 - Chithiraputhiran, S. A1 - Cyr, M. A1 - Dehghan, A. A1 - Dombrowski-Daube, K. A1 - Dubey, A. A1 - Ducman, V. A1 - Gluth, Gregor A1 - Nanukuttan, S. A1 - Peterson, K. A1 - Puertas, F. A1 - van Riessen, A. A1 - Torres-Carrasco, M. A1 - Ye, G. A1 - Zuo, Y. T1 - RILEM TC 247-DTA round robin test: mix design and reproducibility of compressive strength of alkali-activated concretes N2 - The aim of RILEM TC 247-DTA ‘Durability Testing of Alkali-Activated Materials’ is to identify and validate methodologies for testing the durability of alkali-activated concretes. To underpin the durability testing work of this committee, five alkali-activated concrete mixes were developed based on blast furnace slag, fly ash, and flash-calcined metakaolin. The concretes were designed with different intended performance levels, aiming to assess the capability of test methods to discriminate between concretes on this basis. A total of fifteen laboratories worldwide participated in this round robin test programme, where all concretes were produced with the same mix designs, from single-source aluminosilicate precursors and locally available aggregates. This paper reports the mix designs tested, and the compressive strength results obtained, including critical insight into reasons for the observed variability in strength within and between laboratories. KW - Alkali-activated materials KW - Alkali-activated slag KW - Compressive strength KW - Concrete KW - Mix-design PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-489131 DO - https://doi.org/10.1617/s11527-019-1396-z SN - 1359-5997 SN - 1871-6873 VL - 52 IS - 5 SP - Article Number 99 PB - Springer Nature AN - OPUS4-48913 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoevelmann, J. A1 - Stawski, T. M. A1 - Besselink, R. A1 - Freeman, H. M. A1 - Dietmann, K. M. A1 - Mayanna, S. A1 - Pauw, Brian Richard A1 - Benning, L. G. T1 - A template-free and low temperature method for the synthesis of mesoporous magnesium phosphate with uniform pore structure and high surface area N2 - Mesoporous phosphates are a group of nanostructured materials with promising applications, particularly in biomedicine and catalysis. However, their controlled synthesis via conventional template-based routes presents a number of challenges and limitations. Here, we show how to synthesize a mesoporous Magnesium phosphate with a high surface area and a well-defined pore structure through thermal decomposition of a crystalline struvite (MgNH4PO4·6H2O) precursor. In a first step, struvite crystals with various morphologies and sizes, ranging from a few micrometers to several millimeters, had been synthesized from supersaturated aqueous solutions (saturation index (SI) between 0.5 and 4) at ambient pressure and temperature conditions. Afterwards, the crystals were thermally treated at 70–250 °C leading to the release of structurally bound water (H2O) and ammonia (NH3). By combining thermogravimetric analyses (TGA), scanning and transmission electron microscopy (SEM, TEM), N2 sorption analyses and small- and wide-angle X-ray scattering (SAXS/WAXS) we show that this decomposition process results in a pseudomorphic transformation of the original struvite into an amorphous Mg-phosphate. Of particular importance is the fact that the final material is characterized by a very uniform mesoporous structure with 2–5 nm wide pore channels, a large specific surface area of up to 300 m2 g−1 and a total pore volume of up to 0.28 cm3 g−1. Our struvite decomposition method is well controllable and reproducible and can be easily extended to the synthesis of other mesoporous phosphates. In addition, the so produced mesoporous material is a prime candidate for use in biomedical applications considering that Magnesium phosphate is a widely used, non-toxic substance that has already shown excellent biocompatibility and biodegradability. KW - Struvite KW - SAXS KW - Scattering KW - Nanoporous KW - Geology PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-477130 DO - https://doi.org/10.1039/c8nr09205b VL - 11 IS - 14 SP - 6939 EP - 6951 PB - Royal Society of Chemistry AN - OPUS4-47713 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Descalzo, Ana B. A1 - Ashokkumar, Pichandi A1 - Shen, Z. A1 - Rurack, Knut T1 - On the Aggregation Behaviour and Spectroscopic Properties of Alkylated and Annelated BoronDipyrromethene (BODIPY) Dyes in Aqueous Solution N2 - The tendency of boron-dipyrromethene (BODIPY) dyes to associate in water is well known, and usually a cause for inferior fluorescence properties. Synthetic efforts to chemically improve BODIPYs’ water solubility and minimize this problem have been numerous in the past. However, a deeper understanding of the phenomena responsible for fluorescence quenching is still required. Commonly, the spectroscopic behaviour in aqueous media has been attributed to aggregate or excimer formation, with such works often centring on a single BODIPY family. Herein, we provide an integrating discussion including very diverse types of BODIPY dyes. Our studies revealed that even subtle structural changes can distinctly affect the association behaviour of the fluorophores in water, involving different photophysical processes. The palette of behaviour found ranges from unperturbed emission, to the formation of H or J aggregates and excimers, to the involvement of tightly bound, preformed excimers. These results are a first step to a more generalized understanding of spectroscopic properties vs. structure, facilitating future molecular design of BODIPYs, especially as probes for biological applications. KW - Aggregates KW - BODIPY KW - Excimers KW - Fluorescence KW - Photophysics PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-497771 DO - https://doi.org/10.1002/cptc.201900235 SN - 2367-0932 VL - 4 IS - 2 SP - 120 EP - 131 PB - WILEY-VCH CY - Weinheim AN - OPUS4-49777 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 - 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 - Yildirim, Arda A1 - Sentker, K. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Huber, P. A1 - Schönhals, Andreas T1 - Collective orientational order and phase behavior of a discotic liquid crystal under nanoscale confinement N2 - The phase behavior and molecular ordering of hexakishexyloxy triphenylene (HAT6) DLC under cylindrical nanoconfinement is studied utilizing differential scanning calorimetry (DSC) and dielectric spectroscopy (DS), where cylindrical nanoconfinement is established through embedding HAT6 into the nanopores of anodic aluminum oxide membranes (AAO), and a silica membrane with pore diameters ranging from 161 nm down to 12 nm. Both unmodified and modified pore walls were considered, and in the latter case the pore walls of AAO membranes were chemical treated with n octadecylphosphonic acid (ODPA) resulting in the formation of a 2.2 nm thick layer of grafted alkyl chains. Phase transition enthalpies decrease with decreasing pore size, indicating that a large proportion of the HAT6 molecules within the pores has a disordered structure, which increases with decreasing pore size for both pore walls. In the case of the ODPA modification the amount of ordered HAT6 is increased compared to the unmodified case. The pore size dependencies of the phase transition temperatures were approximated using the Gibbs Thomson equation, where the estimated surface tension is dependent on the molecular ordering of HAT6 molecules within the pores and upon their surface. DS was employed to investigate the molecular ordering of HAT6 within the nanopores. These investigations revealed that with a pore size of around 38 nm, for the samples with the unmodified pore walls, the molecular ordering changes from planar axial to homeotropic radial. However, the planar axial configuration, which is suitable for electronic applications, can be successfully preserved through ODPA modification for most of the pore sizes. KW - Discotic Liquid Crystals KW - Nanoconfinement PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475222 DO - https://doi.org/10.1039/c8na00308d SN - 2516-0230 VL - 1 IS - 3 SP - 1104 EP - 1116 PB - RSC AN - OPUS4-47522 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gramse, G. A1 - Schönhals, Andreas A1 - Kienberger, F. T1 - Nanoscale dipole dynamics of protein membranes studied by broadband dielectric microscopy N2 - We investigate the nearfield dipole mobility of protein membranes in a wide frequency range from 3 kHz to 10 GHz. The results of our nanoscale dielectric images and spectra of bacteriorhodopsin (bR) reveal Debye relaxations with time constants of τ ∼ 2 ns and τ ∼ 100 ns being characteristic of the Dipole moments of the bR retinal and α-helices, respectively. However, the dipole mobility and therefore the protein biophysical function depend critically on the amount of surface water surrounding the protein, and the characteristic mobility in the secondary structure is only observed for humidity levels <30%. Our results have been achieved by adding the frequency as a second fundamental dimension to quantitative dielectric microscopy. The key elements for the success of this advanced technique are the employed heterodyne detection scheme, the broadband electrical signal source, a high frequency optimized cabling, development of calibration procedures and precise finite element modelling. Our study demonstrates the exciting possibilities of broadband dielectric microscopy for the investigation of dynamic processes in cell bioelectricity at the individual molecular level. Furthermore, the technique may shed light on local dynamic processes in related materials science applications like semiconductor Research or nano-electronics. KW - Broadband dielectric microscopy PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475230 DO - https://doi.org/10.1039/c8nr05880f SN - 2040-3372 VL - 11 IS - 10 SP - 4303 EP - 4309 PB - RSC AN - OPUS4-47523 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Röhsler, Andreas A1 - Sobol, Oded A1 - Unger, Wolfgang A1 - Böllinghaus, Thomas T1 - Comprehensive study of deuterium-induced effects in in austenitic stainless steel AISI 304L N2 - The damaging impact of hydrogen on the austenitic stainless steel AISI 304 L was analysed. To this aim, samples were charged electrochemically with the hydrogen isotope deuterium (2H, D) and examined with time-of-flight secondary ion mass spectrometry (ToF-SIMS) and electron backscatter diffraction (EBSD). The fusion of the obtained chemical and structural information revealed local enrichment of deuterium in austenite, transformation into martensite, crack formation and severe roughening of the specimen surface. The results indicated that martensite was not only formed during charging but also during Desorption and ToF-SIMS examinations. Furthermore, cross-sections of deuterium-charged samples revealed that in preferred deformation bands a g/ε/a 0 evolution is taking place. By means of microscopic analyses and carrier gas hot extraction (CGHE), it was found that the use of NaAsO2 as recombination poison decreased the uptake of hydrogen significantly and resulted in severe precipitation on the specimen surfaces. This is in contrast to the popular presumption that NaAsO2 enhances the uptake of hydrogen (and deuterium) during electrochemical charging by hampering its recombination from Atoms to molecules. KW - AISI 304L KW - Hydrogen KW - ToF-SIMS KW - Deuterium KW - Martensite PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-477540 DO - https://doi.org/10.1016/j.ijhydene.2019.03.058 SN - 0360-3199 SN - 1879-3487 VL - 44 IS - 23 SP - 12228 EP - 12238 PB - Elsevier Ltd. AN - OPUS4-47754 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwibbert, Karin A1 - Menzel, F. A1 - Epperlein, N. A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Bacterial adhesion on femtosecond laser-modified polyethylene N2 - In this study, femtosecond laser-induced sub-micrometer structures are generated to modify polyethylene (PE) surface topographies. These surfaces were subjected to bacterial colonization studies with Escherichia coli and Staphylococcus aureus as test strains. The results reveal that the nanostructures do not influence S. aureus coverage, while the adhesion of E. coli is reduced. KW - Bacterial adhesion KW - Laser-modified surface KW - Polyethylene KW - Laser-induced nanostructures KW - Biofilm PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492280 DO - https://doi.org/10.3390/ma12193107 VL - 12 IS - 19 SP - 3107 PB - MDPI CY - Basel, Schweiz AN - OPUS4-49228 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 - 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 - 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 - Radnik, Jörg A1 - Dang, T. T. H. A1 - Gatla, S. A1 - Raghuwanshi, V. S. A1 - Tatchev, D. A1 - Hoell, A. T1 - Identifying the location of Cu ions in nanostructured SAPO-5 molecular sieves and its impact on the redox properties N2 - Combining X-ray Absorption Fine Spectroscopy (XAFS) with Anomalous Small-Angle X-ray Scattering (ASAXS) determines the location of Cu2+ ions in silicoaluminophosphate (SAPO-5) frameworks prepared by hydrothermal crystallization or impregnation. As expected, for the hydrothermally prepared sample, incorporation in the SAPO-5 framework was observed. For the first time preferential location of Cu2+ ions at the inner and outer surfaces of the framework is determined. Temperature-Programmed Reduction (TPR) and X-ray Photoelectron Spectroscopy (XPS) investigations demonstrated that such Cu2+ is stable in an argon (Ar) atmosphere up to 550 °C and can only be reduced under a hydrogen atmosphere. In contrast, Cu2+ deposited by impregnation on the pure SAPO-5 framework can be easily reduced to Cu+ in an Ar atmosphere. At lower Cu amounts, mononuclear tetrahedrally coordinated Cu species were formed which are relatively stable in the monovalent form. In contrast, at higher Cu amounts, CuO particles were found which change easily between the mono- and bivalent species. KW - Nanostructured material KW - Molecular sieves KW - X-ray absorption Fine Spectroscopy KW - Anomalous Small Angle X-ray Scattering KW - X-ray Photoelectron Spectroscopy PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474793 DO - https://doi.org/10.1039/c8ra10417d SN - 2046-2069 VL - 9 IS - 12 SP - 6429 EP - 6437 PB - RSC AN - OPUS4-47479 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 - 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 - 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 - 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, Christos 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 - Buljak, V. A1 - Oesch, Tyler A1 - Bruno, Giovanni T1 - Simulating fiber-reinforced concrete mechanical performance using CT-based fiber orientation data N2 - The main hindrance to realistic models of fiber-reinforced concrete (FRC) is the local materials property variation, which does not yet reliably allow simulations at the structural level. The idea presented in this paper makes use of an existing constitutive model, but resolves the problem of localized material variation through X-ray computed tomography (CT)-based pre-processing. First, a three-point bending test of a notched beam is considered, where pre-test fiber orientations are measured using CT. A numerical model is then built with the zone subjected to progressive damage, modeled using an orthotropic damage model. To each of the finite elements within this zone, a local coordinate system is assigned, with its longitudinal direction defined by local fiber orientations. Second, the parameters of the constitutive damage model are determined through inverse analysis using load-displacement data obtained from the test. These parameters are considered to clearly explain the material behavior for any arbitrary external action and fiber orientation, for the same geometrical properties and volumetric ratio of fibers. Third, the effectiveness of the resulting model is demonstrated using a second, “control” experiment. The results of the “control” experiment analyzed in this research compare well with the model results. The ultimate strength was predicted with an error of about 6%, while the work-of-load was predicted within 4%. It demonstrates the potential of this method for accurately predicting the mechanical performance of FRC components. KW - Fiber-reinforced concrete KW - X-ray computed tomography (CT) KW - Anisotropic fiber orientation KW - Inverse analysis PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474728 DO - https://doi.org/10.3390/ma12050717 SN - 1996-1944 VL - 12 IS - 5 SP - 717, 1 EP - 16 PB - MDPI AN - OPUS4-47472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mishurova, Tatiana A1 - Artzt, K. A1 - Haubrich, J. A1 - Requena, G. A1 - Bruno, Giovanni T1 - Exploring the correlation between subsurface residual stresses and manufacturing parameters in laser powder bed fused Ti-6Al-4V N2 - Subsurface residual stresses (RS) were investigated in Ti-6Al-4V cuboid samples by means of X-ray synchrotron diffraction. The samples were manufactured by laser powder bed fusion (LPBF) applying different processing parameters, not commonly considered in open literature, in order to assess their influence on RS state. While investigating the effect of process parameters used for the calculation of volumetric energy density (such as laser velocity, laser power and hatch distance), we observed that an increase of energy density led to a decrease of RS, although not to the same extent for every parameter variation. Additionally, the effect of support structure, sample roughness and LPBF machine effects potentially coming from Ar flow were studied. We observed no influence of support structure on subsurface RS while the orientation with respect to Ar flow showed to have an impact on RS.We conclude recommending monitoring such parameters to improve part reliability and reproducibility. KW - Additive manufacturing KW - Synchrotron X-ray diffraction KW - Residual stress KW - Ti-6Al-4V PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474281 DO - https://doi.org/10.3390/met9020261 SN - 2075-4701 VL - 9 IS - 2 SP - 261, 1 EP - 13 PB - MDPI AN - OPUS4-47428 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Laquai, René A1 - Gouraud, F. A1 - Müller, Bernd R. A1 - Huger, M. A1 - Chotard, T. A1 - Antou, G. A1 - Bruno, Giovanni T1 - Evolution of Thermal Microcracking in Refractory ZrO2-SiO2 after Application of External Loads at High Temperatures N2 - Zirconia-based cast refractories are widely used for glass furnace applications. Since they have to withstand harsh chemical as well as thermo-mechanical environments, internal stresses and microcracking are often present in such materials under operating conditions (sometimes in excess of 1700 °C). We studied the evolution of thermal (CTE) and mechanical (Young’s modulus) properties as a function of temperature in a fused-cast refractory containing 94 wt.% of monoclinic ZrO2 and 6 wt.% of a silicate glassy phase. With the aid of X-ray refraction techniques (yielding the internal specific surface in materials), we also monitored the evolution of microcracking as a function of thermal cycles (crossing the martensitic phase transformation around 1000 °C) under externally applied stress. We found that external compressive stress leads to a strong decrease of the internal surface per unit volume, but a tensile load has a similar (though not so strong) effect. In agreement with existing literature on -eucryptite microcracked ceramics, we could explain These phenomena by microcrack closure in the load direction in the compression case, and by microcrack propagation (rather than microcrack nucleation) under tensile conditions. KW - Electro-fused zirconia KW - Microcracking KW - Synchrotron x-ray refraction radiography (SXRR) KW - Thermal expansion PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-477431 DO - https://doi.org/10.3390/ma12071017 VL - 12 IS - 7 SP - 1 EP - 15 PB - MDPI AN - OPUS4-47743 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mieller, Björn T1 - Influence of test procedure on dielectric breakdown strength of alumina N2 - Dielectric strength testing of ceramics can be performed with various setups and parameters. Comparisons of results from different sources are often not meaningful, because the results are strongly dependent on the actual testing procedure. The aim of this study is to quantify the influence of voltage ramp rate, electrode size, electrode conditioning, and sample thickness on the measured AC dielectric strength of a commercial alumina. Mean values, Weibull moduli, and failure probabilities determined in standardized short time tests are evaluated and related to withstand voltage tests. Dielectric strength values in the range from 21.6 to 33.2 kV/mm were obtained for the same material using different testing procedures. Short time tests resulted in small standard deviations (< 2 kV/mm) and high Weibull moduli around 30, while withstand tests at voltage levels with low and virtual zero failure probability in short time tests resulted in large scatter of withstand time and Weibull moduli < 1. The strong decrease in Weibull moduli is attributed to progressive damage from partial discharge and depolarization during AC testing. These findings emphasize the necessity of a thorough documentation of testing procedure and highlight the importance of withstand voltage tests for a comprehensive material characterization. KW - Ceramic KW - High-voltage testing KW - Dielectric breakdown KW - Alumina PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483852 DO - https://doi.org/10.1007/s40145-018-0310-4 SN - 2226-4108 SN - 2227-8508 VL - 8 IS - 2 SP - 247 EP - 255 PB - Springer AN - OPUS4-48385 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 - 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 - 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 - Schmidt, C. A1 - Hensen, C. A1 - Wallmann, K. A1 - Liebetrau, V. A1 - Tatzel, Michael A1 - Schurr, S. L. A1 - Kutterolf, S. A1 - Haffert, L. A1 - Geilert, Sonja A1 - Hübscher, C. A1 - Lebas, E. A1 - Heuser, A. A1 - Schmidt, M. A1 - Strauss, H. A1 - Vogl, Jochen A1 - Hansteen, T. T1 - Origin of High Mg and SO4 Fluids in Sediments of the Terceira Rift, Azores‐Indications for Caminite Dissolution in a Waning Hydrothermal System N2 - During R/V Meteor cruise 141/1, pore fluids of near surface sediments were investigated to find indications for hydrothermal activity in the Terceira Rift (TR), a hyperslow spreading center in the Central North Atlantic Ocean. To date, submarine hydrothermal fluid venting in the TR has only been reported for the D. João de Castro seamount, which presently seems to be inactive. Pore fluids sampled close to a volcanic cone at 2,800‐m water depth show an anomalous composition with Mg, SO4, and total alkalinity concentrations significantly higher than seawater and a nearby reference core. The most straightforward way of interpreting these deviations is the dissolution of the hydrothermally formed mineral caminite (MgSO4 0.25 Mg (OH)2 0.2H2O). This interpretation is corroborated by a thorough investigation of fluid isotope systems (δ26Mg, δ30Si, δ34S, δ44/42Ca, and 87Sr/86Sr). Caminite is known from mineral assemblages with anhydrite and forms in hydrothermal recharge zones only under specific conditions such as high fluid temperatures and in altered oceanic crust, which are conditions generally met at the TR. We hypothesize that caminite was formed during hydrothermal activity and is now dissolving during the waning state of the hydrothermal system, so that caminite mineralization is shifted out of its stability zone. Ongoing fluid circulation through the basement is transporting the geochemical signal via slow advection toward the seafloor. KW - Isotope ratio KW - Delta value KW - Pore fluids KW - Magnesium KW - Hydrothermal fluid PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503430 DO - https://doi.org/10.1029/2019GC008525 VL - 20 IS - 12 SP - 6078 EP - 6094 PB - Wiley AN - OPUS4-50343 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sarhan, R. M. A1 - Koopman, W. A1 - Schuetz, R. A1 - Schmid, Thomas A1 - Liebig, F. A1 - Koetz, J. A1 - Bargheer, M. T1 - The importance of plasmonic heating for the plasmondriven photodimerization of 4-nitrothiophenol N2 - Metal nanoparticles form potent nanoreactors, driven by the optical generation of energetic electrons and nanoscale heat. The relative influence of these two factors on nanoscale chemistry is strongly debated. This article discusses the temperature dependence of the dimerization of 4-nitrothiophenol (4-NTP) into 4,4′-dimercaptoazobenzene (DMAB) adsorbed on gold nanoflowers by Surface-Enhanced Raman Scattering (SERS). Raman thermometry shows a significant optical heating of the particles. The ratio of the Stokes and the anti-Stokes Raman signal moreover demonstrates that the molecular temperature during the reaction rises beyond the average crystal lattice temperature of the plasmonic particles. The product bands have an even higher temperature than reactant bands, which suggests that the reaction proceeds preferentially at thermal hot spots. In addition, kinetic measurements of the reaction during external heating of the reaction environment yield a considerable rise of the reaction rate with temperature. Despite this significant heating effects, a comparison of SERS spectra recorded after heating the sample by an external heater to spectra recorded after prolonged illumination shows that the reaction is strictly photo-driven. While in both cases the temperature increase is comparable, the dimerization occurs only in the presence of light. Intensity dependent measurements at fixed temperatures confirm this finding. KW - Nanoparticles KW - Plasmonic heating KW - Raman spectroscopy PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475140 DO - https://doi.org/10.1038/s41598-019-38627-2 SN - 2045-2322 VL - 9 IS - 1 SP - 3060, 1 EP - 8 PB - Nature Publishing Group AN - OPUS4-47514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Domonov, D.P. A1 - Pechenyuk, S.I. A1 - Semushina, Y.P. A1 - Yusenko, Kirill T1 - Solid state transformation in inner coordination sphere of [Co(NH3)6][Fe(C2O4)3]·3H2O as a route to access catalytically active Co-Fe materials N2 - Thermal decomposition of [Co(NH₃)₆][Fe(C₂O₄)₃]∙3H₂O in argon atmosphere, at a low heating rate (3°/min), and in large amounts of the initial complex (~0.1 mole), has been studied. It was possible to distinguish four decomposition steps upon heating: In the temperature range of 50⁻100 °C-the loss of crystal water; 100⁻190 °C-stability region of dehydrated complex; 230⁻270 °C-the range of stability of intermediate phase with the formula CoFe(NH₃)₂(C₂O₄)₂; 270⁻350 °C-thermal decomposition of the intermediate with the formation of metallic products and further air oxidation with the formation of Co1.5Fe1.5O₄. Catalytic properties of thermolysis products were tested in the decomposition reaction of H₂O₂ (inactive), oxidation of acetone (average activity), and decomposition of ammonium perchlorate (highly active). KW - Double complex salts KW - Catalysts KW - Single-source precursors PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474014 DO - https://doi.org/10.3390/ma12020221 SN - 1996-1944 VL - 12 IS - 2 SP - 221, 1 EP - 10 PB - mdpi CY - Zürich AN - OPUS4-47401 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 - Choi, Youngeun A1 - Schmidt, Carsten A1 - Tinnefeld, Philip A1 - Bald, Ilko A1 - Roedinger, Stefan T1 - A new reporter design based on DNA origami nanostructures for quantification of short oligonucleotides using microbeads N2 - The DNA origami technique has great potential for the development of brighter and more sensitive reporters for fluorescence based detection schemes such as a microbead-based assay in diagnostic applications. The nanostructures can be programmed to include multiple dye molecules to enhance the measured signal as well as multiple probe strands to increase the binding strength of the target oligonucleotide to these nanostructures. Here we present a proof-of-concept study to quantify short oligonucleotides by developing a novel DNA origami based reporter system, combined with planar microbead assays. Analysis of the assays using the VideoScan digital imaging platform showed DNA origami to be a more suitable reporter candidate for quantification of the target oligonucleotides at lower concentrations than a conventional reporter that consists of one dye molecule attached to a single stranded DNA. Efforts have been made to conduct multiplexed analysis of different targets as well as to enhance fluorescence signals obtained from the reporters. We therefore believe that the quantification of short oligonucleotides that exist in low copy numbers is achieved in a better way with the DNA origami nanostructures as reporters. KW - Origami KW - Nanostructures KW - Microbeads KW - DNA origami KW - Oligonucleotides PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476443 DO - https://doi.org/10.1038/s41598-019-41136-x SN - 2045-2322 VL - 9 SP - 4769, 1 EP - 8 PB - Nature AN - OPUS4-47644 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Treiling, S. A1 - Wang, Cui A1 - Förster, C. A1 - Reichenauer, F. A1 - Kalmbach, J. A1 - Boden, P. A1 - Harris, J. P. A1 - Carrella, L. M. A1 - Rentschler, E. A1 - Resch-Genger, Ute A1 - Reber, C. A1 - Seitz, M. A1 - Gerhards, M. A1 - Heinze, K. T1 - Luminescence and Light-Driven Energy and Electron Transfer from an Exceptionally Long-Lived Excited State of a Non-Innocent Chromium(III) Complex N2 - Photoactive metal complexes employing Earth‐abundant metal ions are a key to sustainable photophysical and photochemical applications. We exploit the effects of an inversion center and ligand non‐innocence to tune the luminescence and photochemistry of the excited state of the [CrN6] chromophore [Cr(tpe)2]3+ with close to octahedral symmetry (tpe=1,1,1‐tris(pyrid‐2‐yl)ethane). [Cr(tpe)2]3+ exhibits the longest luminescence lifetime (τ=4500 μs) reported up to date for a molecular polypyridyl chromium(III) complex together with a very high luminescence quantum yield of Φ=8.2 % at room temperature in fluid solution. Furthermore, the tpe ligands in [Cr(tpe)2]3+ are redox non‐innocent, leading to reversible reductive chemistry. The excited state redox potential and lifetime of [Cr(tpe)2]3+ surpass those of the classical photosensitizer [Ru(bpy)3]2+ (bpy=2,2′‐bipyridine) enabling energy transfer (to oxygen) and photoredox processes (with azulene and tri(n‐butyl)amine). KW - Quantum yield KW - Cr(III) complex KW - Longst luminescence lifetime KW - Electron transfer PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494870 DO - https://doi.org/10.1002/anie.201909325 VL - 58 SP - 2 EP - 13 PB - Wiley-VCH AN - OPUS4-49487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Anja A1 - Heinrich, Thomas A1 - Tougaard, S. A1 - Werner, W. S. M. A1 - Hronek, M. A1 - Kunz, Valentin A1 - Radnik, Jörg A1 - Stockmann, Jörg M. A1 - Hodoroaba, Vasile-Dan A1 - Benemann, Sigrid A1 - Nirmalananthan-Budau, Nithiya A1 - Geißler, Daniel A1 - Sparnacci, K. A1 - Unger, Wolfgang T1 - Determining the thickness and completeness of the shell of polymer core-shell nanoparticles by X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and transmission scanning electron microscopy N2 - Core–shell nanoparticles (CSNPs) have become indispensable in various industrial applications. However, their real internal structure usually deviates from an ideal core–shell structure. To control how the particles perform with regard to their specific applications, characterization techniques are required that can distinguish an ideal from a nonideal morphology. In this work, we investigated poly(tetrafluoroethylene)–poly(methyl methacrylate) (PTFE–PMMA) and poly(tetrafluoroethylene)–polystyrene (PTFE–PS) polymer CSNPs with a constant core diameter (45 nm) but varying shell thicknesses (4–50 nm). As confirmed by transmission scanning electron microscopy (T-SEM), the shell completely covers the core for the PTFE–PMMA nanoparticles, while the encapsulation of the core by the shell material is incomplete for the PTFE–PS nanoparticles. X-ray photoelectron spectroscopy (XPS) was applied to determine the shell thickness of the nanoparticles. The software SESSA v2.0 was used to analyze the intensities of the elastic peaks, and the QUASES software package was employed to evaluate the shape of the inelastic background in the XPS survey spectra. For the first time, nanoparticle shell thicknesses are presented, which are exclusively based on the analysis of the XPS inelastic background. Furthermore, principal component analysis (PCA)-assisted time-of-flight secondary-ion mass spectrometry (ToF-SIMS) of the PTFE–PS nanoparticle sample set revealed a systematic variation among the samples and, thus, confirmed the incomplete encapsulation of the core by the shell material. As opposed to that, no variation is observed in the PCA score plots of the PTFE–PMMA nanoparticle sample set. Consequently, the complete coverage of the core by the shell material is proved by ToF-SIMS with a certainty that cannot be achieved by XPS and T-SEM. KW - XPS KW - T-SEM KW - ToF-SIMS KW - Core-shell nanoparticles PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499165 DO - https://doi.org/10.1021/acs.jpcc.9b09258 VL - 123 IS - 49 SP - 29765 EP - 29775 PB - American Chemical Society CY - Washington, DC AN - OPUS4-49916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jürgens, Maria A1 - Olbricht, Jürgen A1 - Fedelich, Bernard A1 - Skrotzki, Birgit T1 - Low Cycle Fatigue and Relaxation Performance of Ferritic–Martensitic Grade P92 Steel N2 - Due to their excellent creep resistance and good oxidation resistance, 9–12% Cr ferritic–martensitic stainless steels are widely used as high temperature construction materials in power plants. However, the mutual combination of different loadings (e.g., creep and fatigue), due to a “flexible” operation of power plants, may seriously reduce the lifetimes of the respective components. In the present study, low cycle fatigue (LCF) and relaxation fatigue (RF) tests performed on grade P92 helped to understand the behavior of ferritic–martensitic steels under a combined loading. The softening and lifetime behavior strongly depend on the temperature and total strain range. Especially at small strain amplitudes, the lifetime is seriously reduced when adding a hold time which indicates the importance of considering technically relevant small strains. KW - Ferritic–martensitic steel KW - P92 KW - Low cycle fatigue KW - Relaxation fatigue KW - Cyclic softening PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473905 DO - https://doi.org/10.3390/met9010099 VL - 9 IS - 1 SP - 99, 1 EP - 25 PB - MDPI AN - OPUS4-47390 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 - 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 - 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 - Carl, Peter A1 - Ramos, Inês I. A1 - Segundo, Marcela A. A1 - Schneider, Rudolf T1 - Antibody conjugation to carboxyl-modified microspheres through N-hydroxysuccinimide chemistry for automated immunoassay applications: A general procedure N2 - Immunochemical techniques are the workhorse for sample enrichment and detection of a large variety of analytes. In contrast to classical microtiter plate-based assays, microparticles are a next generation solid support, as they promote automation of immunoassays using flow-based techniques. Antibody immobilization is a crucial step, as these reagentsmare expensive, and inefficient coupling can result in low sensitivities. This paper proposes a general procedure for efficient immobilization of antibodies onto TentaGel particles, via Nhydroxysuccinimide chemistry. The goal was the preparation of solid supports with optimum immunorecognition, while increasing the sustainability of the process. The influence of buffer composition, activation and coupling time, as well as the amount of antibody on the immobilization efficiency was investigated, resorting to fluorophore-labeled proteins and fluorescence imaging. Buffer pH and activation time are the most important parameters for efficient coupling. It is demonstrated, that the hydrolysis of N-hydroxysuccinimide esters occurs at similar rates as in solution, limiting the utilizable time for coupling. Finally, applicability of the generated material for automated affinity extraction is demonstrated on the mesofluidic platform lab-on-valve. KW - Mesofluidics KW - Bead injections KW - ELISA KW - Carbamazepine KW - Biomarkers PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483919 DO - https://doi.org/10.1371/journal.pone.0218686 SN - 1932-6203 VL - 14 IS - 6 SP - e0218686, 1 EP - 18 PB - Public Library of Science CY - San Francisco, California, USA AN - OPUS4-48391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Souza Machado, A. A. A1 - Lau, C. W. A1 - Kloas, W. A1 - Bergmann, J. A1 - Bachelier, J. B. A1 - Faltin, E. A1 - Becker, Roland A1 - Görlich, A. S. A1 - Rillig, M. C. T1 - Microplastics can change soil properties and affect plant performance N2 - Microplastics can affect biophysical properties of the soil. However, little is known about the cascade of events in fundamental levels of terrestrial ecosystems, i.e., starting with the changes in soil abiotic properties and propagating across the various components of soil−plant interactions, including soil microbial communities and plant traits. We investigated here the effects of six different microplastics (polyester fibers, polyamide beads, and four fragment types: polyethylene, polyester terephthalate, polypropylene, and polystyrene) on a broad suite of proxies for soil health and performance of spring onion (Allium fistulosum). Significant changes were observed in plant biomass, tissue elemental composition, root traits, and soil microbial activities. These plant and soil responses to microplastic exposure were used to propose a causal model for the mechanism of the effects. Impacts were dependent on particle type, i.e., microplastics with a shape similar to other natural soil particles elicited smaller differences from control. Changes in soil structure and water dynamics may explain the observed results in which polyester fibers and polyamide beads triggered the most pronounced impacts on plant traits and function. The findings reported here imply that the pervasive microplastic contamination in soil may have consequences for plant performance and thus for agroecosystems and terrestrial biodiversity. KW - Mikroplastik KW - Boden KW - Pflanzenwachstum PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484181 DO - https://doi.org/10.1021/acs.est.9b01339 SN - 0013-936X SN - 1520-5851 VL - 53 IS - 10 SP - 6044 EP - 6052 PB - ACS AN - OPUS4-48418 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kotthoff, Lisa A1 - Lisec, Jan A1 - Schwerdtle, T. A1 - Koch, Matthias T1 - Prediction of transformation products of monensin by electrochemistry compared to microsomal assay and hydrolysis N2 - The knowledge of transformation pathways and identification of transformation products (TPs) of veterinary drugs is important for animal health, food, and environmental matters. The active agent Monensin (MON) belongs to the ionophore antibiotics and is widely used as a veterinary drug against coccidiosis in broiler farming. However, no electrochemically (EC) generated TPs of MON have been described so far. In this study, the online coupling of EC and mass spectrometry (MS) was used for the generation of oxidative TPs. EC-conditions were optimized with respect to working electrode material, solvent, modifier, and potential polarity. Subsequent LC/HRMS (liquid chromatography/high resolution mass spectrometry) and MS/MS experiments were performed to identify the structures of derived TPs by a suspected target analysis. The obtained EC-results were compared to TPs observed in metabolism tests with microsomes and hydrolysis experiments of MON. Five previously undescribed TPs of MON were identified in our EC/MS based study and one TP, which was already known from literature and found by a microsomal assay, could be confirmed. Two and three further TPs were found as products in microsomal tests and following hydrolysis, respectively. We found decarboxylation, O-demethylation and acid-catalyzed ring-opening reactions to be the major mechanisms of MON transformation. KW - Transformation products KW - Monensin KW - Veterinary drugs KW - Electrochemistry KW - Hydrolysis KW - LC/HRMS PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485689 DO - https://doi.org/10.3390/molecules24152732 SN - 1420-3049 VL - 24 IS - 15 SP - 2732, 1 EP - 12 PB - MDPI CY - Basel AN - OPUS4-48568 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 - Saleh, Maysoon I. A1 - Panas, I. A1 - Frenzel, Florian A1 - Würth, Christian A1 - Rühle, Bastian A1 - Slominskii, Y. A1 - Demchenko, A. A1 - Resch-Genger, Ute T1 - Sensitization of upconverting nanoparticles with a NIR-emissive cyanine dye using a micellar encapsulation approach N2 - Photon upconversion nanomaterials have a wide range of applications, including biosensing and deep-tissue imaging. Their typically very weak and narrow absorption bands together with their size dependent luminescence efficiency can limit their application potential. This has been addressed by increasingly sophisticated core-shell particle architectures including the sensitization with organic dyes that strongly absorb in the near infrared (NIR). In this work, we present a simple water-dispersible micellar system that features energy transfer from the novel NIR excitable dye, 1859 SL with a high molar absorption coefficient and a moderate fluorescence quantum yield to oleate-capped NaYF4:20%Yb(III), 2%Er(III) upconversion nanoparticles (UCNP) upon 808 nm excitation. The micelles were formed using the surfactants Pluronic F-127 and Tween 80 to produce a hydrophilic dye-UCNP system. Successful energy transfer from the dye to the UCNP could be confirmed by emission measurements that revealed the occurrence of upconversion emission upon excitation at 808 nm and an enhancement of the green Er(III) emission compared to direct Er(III) excitation at 808 nm. KW - Upconversion nanoparticles KW - Sensitization KW - NIR dyes KW - Energy transfer PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472300 DO - https://doi.org/10.1088/2050-6120/aafe1f SN - 2050-6120 VL - 7 IS - 1 (Special issue: Upconversion Methods, Applications and Materials) SP - 014003-1 EP - 014003-9 PB - IOP AN - OPUS4-47230 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kröcke, N. A1 - Grebenteuch, S. A1 - Keil, C. A1 - Demtröder, S. A1 - Koch, L. A1 - Thünemann, Andreas A1 - Benning, R. A1 - Haase, H. T1 - Effect of different drying methods on nutrient quality of the yellow mealworm (Tenebrio molitor L.) N2 - Yellow mealworm (Tenebrio molitor L.) represents a sustainable source of proteins and fatty acids for feed and food. Industrial production of mealworms necessitates optimized processing techniques, where drying as the first postharvest procedure is of utmost importance for the quality of the final product. This study examines the nutritional quality of mealworm larvae processed by rack oven drying, vacuum drying or freeze drying, respectively. Proximate composition and fatty acid profile were comparable between the dried larvae. In contrast, larvae color impressions and volatile compound profiles were very much dependent on processing procedure. High-temperature rack oven drying caused pronounced darkening with rather low content of volatiles, pointing toward the progress of Maillard reaction. On the other hand, vacuum drying or freeze drying led to enrichment of volatile Maillard reaction and lipid oxidation intermediates, whose actual sensory relevance needs to be clarified in the future. Beyond sensory and visual importance drying intermediates have to be considered with regard to their metal ion chelating ability; in particular for essential trace elements such as Zn2+. This study found comparable total zinc contents for the differently dried mealworm samples. However, dried larvae, in particular after rack oven drying, had only low zinc accessibility, which was between 20% and 40%. Therefore, bioaccessibility rather than total zinc has to be considered when their contribution to meeting the nutritional requirements for zinc in humans and animals is evaluated. KW - Food PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476320 DO - https://doi.org/10.3390/insects10040084 SN - 2075-4450 VL - 10 IS - 4 SP - 84, 1 EP - 13 PB - MDPI AN - OPUS4-47632 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kotthoff, Lisa A1 - Keller, Julia A1 - Lörchner, Dominique A1 - Mekonnen, Tessema F. A1 - Koch, Matthias T1 - Transformation products of organic contaminants and residues - Overview of current simulation methods N2 - The formation of transformation products (TPs) from contaminants and residues is becoming an increasing focus of scientific community. All organic compounds can form different TPs, thus demonstrating the complexity and interdisciplinarity of this topic. The properties of TPs could stand in relation to the unchanged substance or be more harmful and persistent. To get important information about the generated TPs, methods are needed to simulate natural and manmade transformation processes. Current tools are based on metabolism studies, photochemical methods, electrochemical methods, and Fenton's reagent. Finally, most transformation processes are based on redox reactions. This review aims to compare these methods for structurally different compounds. The groups of pesticides, pharmaceuticals, brominated flame retardants, and mycotoxins were selected as important residues/contaminants relating to their worldwide occurrence and impact to health, food, and environmental safety issues. Thus, there is an increasing need for investigation of transformation processes and identification of TPs by fast and reliable methods. KW - Transformation product KW - Electrochemistry KW - Photochemistry KW - Fenton’s reagent PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474108 DO - https://doi.org/10.3390/molecules24040753 SN - 1420-3049 VL - 24 IS - 4 SP - 753, 1 EP - 23 PB - MDPI CY - Basel AN - OPUS4-47410 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dorgerloh, Ute A1 - Becker, Roland A1 - Kaiser, M. T1 - Evidence for the formation of difluoroacetic acid in chlorofluorocarbon-contaminated ground water N2 - The concentrations of difluoroacetic acid (DFA) and trifluoroacetic acid (TFA) in rainwater and surface water from Berlin, Germany resembled those reported for similar urban areas, and the TFA/DFA ratio in rainwater of 10:1 was in accordance with the literature. In contrast, nearby ground water historically contaminated with 1,1,2-trichloro-1,2,2-trifluoroethane (R113) displayed a TFA/DFA ratio of 1:3. This observation is discussed versus the inventory of microbial Degradation products present in this ground water along with the parent R113 itself. A microbial Transformation of chlorotrifluoroethylene (R1113) to DFA so far has not been reported for environmental media, and is suggested based on well-established mammalian metabolic pathways. KW - Fluoroacetic acid KW - DFA KW - TFA KW - Rainwater KW - Ground water KW - Degradation of refrigerants PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475569 DO - https://doi.org/10.3390/molecules24061039 SN - 1420-3049 VL - 24 IS - 6 SP - 1039, 1 EP - 6 PB - MDPI CY - Basel AN - OPUS4-47556 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tarantini, A. A1 - Wegner, Karl David A1 - Dussert, F. A1 - Sarret, G. A1 - Beal, D. A1 - Mattera, L. A1 - Lincheneau, C. A1 - Proux, O. A1 - Truffier-Boutry, D. A1 - Moriscot, C. A1 - Gallet, B. A1 - Jouneau, P.-H. A1 - Reiss, P. A1 - Carriere, M. T1 - Physicochemical alterations and toxicity of InP alloyed quantum dots aged in environmental conditions: A safer by design evaluation N2 - Due to their unique optical properties, quantum dots (QDs) are used in a number of optoelectronic devices and are forecasted to be used in the near future for biomedical applications. The most popular QD composition consists of cadmium selenide (CdSe) or cadmium telluride (CdTe), which has been shown to pose health risks due to the release of toxic cadmium (Cd) ions. Due to similar optical properties but lower intrinsic toxicity, indium phosphide (InP) QDs have been proposed as a safer alternative. Nevertheless, investigations regarding their safety and possible toxicological effects are still in their infancy. The fate and toxicity of seven different water-dispersible indium (In) based QDs, either pristine or after ageing in a climatic chamber, was evaluated. The core of these QDs was composed of indium, zinc and phosphorus (InZnP) or indium, zinc, phosphorus and sulfur (InZnPS). They were assessed either as core-only or as core-shell QDs, for which the core was capped with a shell of zinc, selenium and sulfur (Zn(Se,S)). Their Surface was functionalized using either penicillamine or glutathione. In their pristine form, these QDs showed essentially no cytotoxicity. The particular case of InZnPS QD showed that core-shell QDs were less cytotoxic than core-only QDs. Moreover, surface functionalization with either penicillamine or glutathione did not appreciably influence cytotoxicity but affected QD stability. These QDs did not lead to over-accumulation of reactive oxygen species in exposed cells, or to any oxidative damage to cellular DNA. However, accelerated weathering in a climatic chamber led to QD precipitation and degradation, together with significant cytotoxic effects. Ageing led to dissociation of IneP and ZneS bonds, and to complexation of In Zn ions with carboxylate and/or phosphate moieties. These results show that InZnP and InZnPS alloyed QDs are safer alternatives to CdSe QDs. They underline the necessity to preserve as much as possible the structural integrity of QDs, for instance by developing more robust shells, in order to ensure their safety for future applications. KW - Indium phosphide KW - Safe by design KW - Toxicity KW - EXAFS PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483070 DO - https://doi.org/10.1016/j.impact.2019.100168 VL - 14 SP - 100168-1 EP - 100168-13 PB - Elsevier AN - OPUS4-48307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neumann, Patrick P. A1 - Kohlhoff, Harald A1 - Hüllmann, Dino A1 - Krentel, Daniel A1 - Kluge, Martin A1 - Dzierliński, M. A1 - Lilienthal, A. J. A1 - Bartholmai, Matthias T1 - Aerial-based gas tomography – from single beams to complex gas distributions N2 - In this paper, we present and validate the concept of an autonomous aerial robot to reconstruct tomographic 2D slices of gas plumes in outdoor environments. Our platform, the so-called Unmanned Aerial Vehicle for Remote Gas Sensing (UAV-REGAS), combines a lightweight Tunable Diode Laser Absorption Spectroscopy (TDLAS) gas sensor with a 3-axis aerial stabilization gimbal for aiming at a versatile octocopter. While the TDLAS sensor provides integral gas concentration measurements, it does not measure the distance traveled by the laser diode’s beam nor the distribution of gas along the optical path. Thus, we complement the set-up with a laser rangefinder and apply principles of Computed Tomography (CT) to create a model of the spatial gas distribution from a set of integral concentration measurements. To allow for a fundamental ground truth evaluation of the applied gas tomography algorithm, we set up a unique outdoor test environment based on two 3D ultrasonic anemometers and a distributed array of 10 infrared gas transmitters. We present results showing its performance characteristics and 2D plume reconstruction capabilities under realistic conditions. The proposed system can be deployed in scenarios that cannot be addressed by currently available robots and thus constitutes a significant step forward for the field of Mobile Robot Olfaction (MRO). KW - Aerial robot olfaction KW - Mobile robot olfaction KW - Gas tomography KW - TDLAS KW - Plume PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487843 DO - https://doi.org/10.1080/22797254.2019.1640078 SP - 1 EP - 16 PB - Taylor & Francis CY - London AN - OPUS4-48784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rastayesh, S. A1 - Long, Lijia A1 - Sørensen, J. D. A1 - Thöns, Sebastian T1 - Risk Assessment and Value of Action Analysis for Icing Conditions of Wind Turbines Close to Highways N2 - The paper presents research results from the Marie Skłodowska-Curie Innovative Training Network INFRASTAR in the field of reliability approaches for decision-making for wind turbines and bridges. This paper addresses the application of Bayesian decision analysis for installation of heating systems in wind turbine blades in cases where an ice detection system is already installed in order to allow wind turbines to be placed close to highways. Generally, application of ice detection and heating systems for wind turbines is very relevant in cases where the wind turbines are planned to be placed close to urban areas and highways, where risks need to be considered due to icing events, which may lead to consequences including human fatality, functional disruptions, and/or economic losses. The risk of people being killed in a car passing on highways near a wind turbine due to blades parts or ice pieces being thrown away in cases of overicing is considered in this paper. The probability of being killed per kilometer and per year is considered for three cases: blade parts thrown away as a result of a partial or total failure of a blade, ice thrown away in two cases, i.e., of stopped wind turbines and of wind turbines in operation. Risks due to blade parts being thrown away cannot be avoided, since low strengths of material, maintenance or manufacturing errors, mechanical or electrical failures may result in failure of a blade or blade part. The blade (parts) thrown away from wind turbines in operation imply possible consequences/fatalities for people near the wind turbines, including in areas close to highways. Similar consequences are relevant for ice being thrown away from wind turbine blades during icing situations. In this paper, we examine the question as to whether it is valuable to put a heating System on the blades in addition to ice detection systems. This is especially interesting in countries with limited space for placing wind turbines; in addition, it is considered if higher power production can be obtained due to less downtime if a heating system is installed. KW - Risk assessment KW - Value of action analysis KW - Icing conditions KW - Wind turbine KW - Blade PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487805 DO - https://doi.org/10.3390/en12142653 VL - 12 IS - 14 SP - 2653-1 EP - 2653-15 PB - MDPI AN - OPUS4-48780 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markwart, J. C. A1 - Battig, Alexander A1 - Kuckhoff, T. A1 - Schartel, Bernhard A1 - Wurm, F. R. T1 - First phosphorus AB2 monomer for flame-retardant hyperbranched polyphosphoesters: AB2vs. A2 + B3 N2 - Branched polymers are an important class of polymers with a high number of terminal groups, lower viscosity compared to their linear analogs and higher miscibility, which makes them especially interesting for flame retardant applications, where the flame retardants (FR) are blended with another polymer matrix. Hyperbranched polyphosphoesters (hbPPEs) are gaining more and more interest in the field of flame retardancy, as low molar mass FRs often have the disadvantage of blooming out or leaching, which is not desired in consumer products. Here, we present the first phosphorus-based AB2 monomer for the synthesis of hbPPEs and assess its flame-retardant performance in an epoxy resin compared to a hbPPE synthesized by an A2 + B3 approach. The hbPPE synthesized from an AB2 monomer exhibited a slightly higher performance compared to a similar hbPPE, which was prepared by A2 + B3 polyaddition, probably due to its higher phosphorus content. KW - Polyphosphoester KW - Hyperbranched KW - Flame retardant KW - Synthesis PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-497570 DO - https://doi.org/10.1039/c9py01156k SN - 1759-9962 VL - 10 IS - 43 SP - 5920 EP - 5930 PB - RSC AN - OPUS4-49757 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 -