TY - JOUR A1 - Hildebrandt, L. A1 - von der Au, Marcus A1 - Zimmermann, T. A1 - Reese, A. A1 - Ludwig, J. A1 - Pröfrock, D. T1 - A metrologically traceable protocol for the quantification of trace metals in different types of microplastic N2 - The presence of microplastic (MP) particles in aquatic environments raised concern About possible enrichment of organic and inorganic pollutants due to their specific surface and chemical properties. In particular the role of metals within this context is still poorly understood. Therefore, the aim of this work was to develop a fully validated acid digestion protocol for metal analysis in different polymers, which is a prerequisite to study such interactions. The proposed digestion protocol was validated using six different certified reference materials in the microplastic size range consisting of polyethylene, polypropylene, acrylonitrile butadiene styrene and polyvinyl chloride. As ICP-MS/MS enabled time-efficient, sensitive and robust analysis of 56 metals in one measurement, the method was suitable to provide mass fractions for a multitude of other elements beside the certified ones (As, Cd, Cr, Hg, Pb, Sb, Sn and Zn). Three different microwaves, different acid mixtures as well as different temperatures in combination with different hold times were tested for optimization purposes. With the exception of Cr in acrylonitrile butadiene styrene, recovery rates obtained using the optimized protocol for all six certified reference materials fell within a range from 95.9% ± 2.7% to 112% ± 7%. Subsequent optimization further enhanced both precision and recoveries ranging from 103% ± 5% to 107 ± 4% (U; k = 2 (n = 3)) for all certified metals (incl. Cr) in acrylonitrile butadiene styrene. The results clearly show the analytical challenges that come along with metal analysis in chemically resistant plastics. Addressing specific analysis Tools for different sorption scenarios and processes as well as the underlying kinetics was beyond this study’s scope. However, the future application of the two recommended thoroughly validated total acid digestion protocols as a first step in the direction of harmonization of metal analysis in/on MP will enhance the significance and comparability of the generated data. It will contribute to a better understanding of the role of MP as vector for trace metals in the environment. KW - Microplatic KW - Digestion KW - Analytical Chemistry PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510727 DO - https://doi.org/10.1371/journal.pone.0236120 VL - 15 IS - 7 SP - e0236120 AN - OPUS4-51072 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zimmermann, T. A1 - von der Au, Marcus A1 - Reese, A. A1 - Klein, O. A1 - Hildebrandt, L. A1 - Pröfrock, D. T1 - Substituting HF by HBF4 – an optimized digestion method for multi-elemental sediment analysis via ICP-MS/MS N2 - Determination of elemental mass fractions in sediments plays a major role in evaluating the environmental status of aquatic ecosystems. Herewith, the optimization of a new total digestion protocol and the subsequent analysis of 48 elements in different sediment reference materials (NIST SRM 2702, GBW 07313, GBW 07311 and JMC-2) based on ICP-MS/MS detection is presented. The developed method applies microwave acid digestion and utilizes HBF4 as fluoride source for silicate decomposition. Similar to established protocols based on HF, HBF4 ensures the dissolution of the silicate matrix, as well as other refractory oxides. As HBF4 is not acutely toxic; no special precautions have to be made and digests can be directly measured via ICP-MS without specific sample inlet systems, evaporation steps or the addition of e.g. H3BO3, in order to mask excess HF. Different acid mixtures with and without HBF4 were evaluated in terms of digestion efficiency based on the trace metal recovery. The optimized protocol (5 mL HNO3, 2 mL HCL, 1 mL HBF4) allows a complete dissolution of the analyzed reference materials, as well as quantitative recoveries for a wide variety of certified analytes. Low recoveries for e.g. Sr, Ba and rare earth elements due to fluoride precipitation of HF-based digestions protocols, can be avoided by the usage of HBF4 instead. Based on the usage of high purity HBF4 all relevant trace, as well as matrix elements can be analyzed with sufficiently low LOQs (0.002 μg L−1 for U up to 6.7 μg L−1 for Al). In total, 34 elements were within a recovery range of 80%–120% for all three analyzed reference materials GBW 07313, GBW 07311 and JMC-2. 14 elements were outside a recovery range of 80%–120% for at least one of the analyzed reference materials. KW - Reference Materials KW - Sediment KW - HF free Digestion PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510480 DO - https://doi.org/10.1039/D0AY01049A SP - 1 EP - 10 PB - Royal Society of Chemistry AN - OPUS4-51048 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kalmbach, J. A1 - Wang, Cui A1 - You, Yi A1 - Förster, C. A1 - Schubert, H. A1 - Heinze, K. A1 - Resch-Genger, Ute A1 - Seitz, M. T1 - Near-IR to near-IR upconversion luminescence in molecular chromium ytterbium salts N2 - Upconversion photoluminescence in hetero-oligonuclear metal complex architectures featuring organic ligands is an interesting but still rarely observed phenomenon, despite its great potential from a basic research and application perspective. In this context, a new photonic material consisting of molecular chromium(III) and ytterbium(III) complex Ions was developed that exhibits excitation-power density-dependent cooperative sensitization of the chromium-centered 2E/2T1 phosphorescence at approximately 775 nm after excitation of the ytterbium band 2F7/2!2F5/2 at approximately 980 nm in the solid state at ambient temperature. The upconversion process is insensitive to atmospheric oxygen and can be observed in the presence of water molecules in the crystal lattice. KW - Upconversion KW - Lanthanide KW - Photoluminescence KW - Quantum yield KW - Photophysics KW - Lifetime KW - Sensor KW - NIR KW - Cr(III) KW - Yb(III) complex KW - Crystal KW - Triplet-triplet annihilation KW - Sensitization KW - Light harvesting PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512619 DO - https://doi.org/10.1002/anie.202007200 SN - 1433-7851 SN - 1521-3773 VL - 59 IS - 42 SP - 18804 EP - 18808 PB - Wiley CY - Weinheim AN - OPUS4-51261 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Li, Q. A1 - Shinde, S. A1 - Grasso, G. A1 - Caroli, A. A1 - Abouhany, R. A1 - Lanzillotta, M. A1 - Pan, G. A1 - Wan, Wei A1 - Rurack, Knut A1 - Sellergren, B. T1 - Selective detection of phospholipids using molecularly imprinted fluorescent sensory core-shell particles N2 - Sphingosine-1-phosphate (S1P) is a bioactive sphingo-lipid with a broad range of activities coupled to its role in G-protein coupled receptor signalling. Monitoring of both intra and extra cellular levels of this lipid is challenging due to its low abundance and lack of robust affinity assays or sensors. We here report on fluorescent sensory core-shell molecularly imprinted polymer (MIP) particles responsive to near physiologically relevant levels of S1P and the S1P receptor modulator fingolimod phosphate (FP) in spiked human serum samples. Imprinting was achieved using the tetrabutylammonium (TBA) salt of FP or phosphatidic acid (DPPA·Na) as templates in combination with a polymerizable nitrobenzoxadiazole (NBD)-urea monomer with the dual role of capturing the phospho-anion and signalling its presence. The monomers were grafted from ca 300 nm RAFT-modified silica core particles using ethyleneglycol dimethacrylate (EGDMA) as crosslinker resulting in 10–20 nm thick shells displaying selective fluorescence response to the targeted lipids S1P and DPPA in aqueous buffered media. Potential use of the sensory particles for monitoring S1P in serum was demonstrated on spiked serum samples, proving a linear range of 18–60 μM and a detection limit of 5.6 μM, a value in the same range as the plasma concentration of the biomarker. KW - Molecularly imprinted polymers KW - Phospholipids KW - Fluorescence KW - Dye monomers PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509485 DO - https://doi.org/10.1038/s41598-020-66802-3 SN - 2045-2322 VL - 10 IS - 1 SP - 9924 PB - Nature Research CY - London AN - OPUS4-50948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Moll, J. A1 - Wang, Cui A1 - Päpcke, A. A1 - Förster, C. A1 - Resch-Genger, Ute A1 - Lochbrunner, S. A1 - Heinze, K. T1 - Green Light Activation of Push-Pull Ruthenium(II) Complexes N2 - Synthesis, characterization, electrochemistry, and photophysics of novel homo- and heteroleptic ruthenium(II) complexes [Ru(cpmp)2] 2+ (22+) and [Ru(cpmp)(ddpd)]2+ (32+) bearing the tridentate ligands 6,2’’-carboxypyridyl-2,2’-methylamine-pyridylpyridine (cpmp) and N,N’-dimethyl-N,N’-dipyridin-2-ylpyridine-2,6-diamine (ddpd) are reported. The complexes possess one (32+) or two (22+) electron-deficient dipyridyl ketone fragments as electron accepting sites enabling intraligand charge transfer (ILCT), ligand-toligand charge transfer (LL’CT) and low-energy metal-to-ligand charge transfer (MLCT) absorptions. The latter peak around 544 nm (green light). 22+ shows 3MLCT phosphorescence in the red to near-infrared spectral region at room temperature in deaerated acetonitrile solution with an emission quantum yield of 1.3 % and a 3MLCT lifetime of 477 ns, while 3 2+ is much less luminescent. This different behaviour is ascribed to the energy gap law and the shape of the parasitic excited 3MC state potential energy surface. This study highlights the importance of the excited state energies and geometries for the actual excited state dynamics. Aromatic and aliphatic amines reductively quench the excited state of 22+ paving the way to photocatalytic applications using low-energy green light as exemplified with the green-light sensitized thiol-ene click reaction. KW - Green light excitation KW - Ruthenium(II) complexes KW - Phosphorescence KW - MLCT KW - Photoinduced electron transfer PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506759 DO - https://doi.org/10.1002/chem.202000871 SP - 1 EP - 13 PB - Wiley-VCH Verlag AN - OPUS4-50675 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Faßbender, Sebastian A1 - Rodiouchkina, K. A1 - Vanhaecke, F. A1 - Meermann, Björn T1 - Method development for on-line species-specific sulfur isotopic analysis by means of capillary electrophoresis/multicollector ICP-mass spectrometry N2 - In this work, a method for species-specific isotopic analysis of sulfur via capillary electrophoresis hyphenated on-line with multicollector ICP-MS (CE/MC-ICP-MS) was developed. Correction for the mass bias caused by instrumental mass discrimination was realized via external correction with multiple-injection sample-standard bracketing. By comparing the isotope ratio measurement results obtained using the newly developed on-line CE/MC-ICP-MS method with those obtained via traditional MC-ICP-MS measurement after analyte/matrix separation by anion exchange chromatography for isotopic reference materials and an in-house bracketing standard, the most suitable data evaluation method could be identified. The repeatability for the sulfate-δ34S value (calculated from 18 measurements of a standard conducted over seven measurement sessions) was 0.57‰ (2SD) and thereby only twice that obtained with off-line measurements (0.30‰, n = 68). As a proof of concept for analysis of samples with a real matrix, the determination of the sulfur isotopic composition of naturally present sulfate was performed for different river systems. The CE/MC-ICP-MS results thus obtained agreed with the corresponding off-line MC-ICP-MS results within the 2SD ranges, and the repeatability of consecutive δ34S measurements (n = 3) was between 0.3‰ and 1.3‰ (2SD). Finally, the isotopic analysis of two different S-species in a river water sample spiked with 2-pyridinesulfonic acid (PSA) was also accomplished. KW - River water sulfate KW - Environmental speciation KW - Sulfur isotopes KW - On-line CE/MC-ICP-MS KW - Multiple-injection sample-standard bracketing PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509549 DO - https://doi.org/10.1007/s00216-020-02781-8 SN - 1618-2642 VL - 412 IS - 23 SP - 5637 EP - 5646 PB - Springer CY - Berlin, Heidelberg AN - OPUS4-50954 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krahl, T. A1 - Beer, F. A1 - Relling, A. A1 - Gawlitza, Kornelia A1 - Rurack, Knut A1 - Kemnitz, E. T1 - Toward Luminescent Composites by Phase Transfer of SrF2 :Eu3+ Nanoparticles Capped with Hydrophobic Antenna Ligands N2 - Transparent dispersions of hydrophobic SrF2 :Eu3+ nanoparticles in cyclohexane with up to 20% europium were obtained by fluorolytic sol-gel synthesis followed by Phase transfer into cyclohexane through capping with sodium dodecylbenzenesulfonate (SDBS). The particles were characterized by TEM, XRD and DLS as spherical objects with a diameter between 6 and 11 nm in dry state. 1H-13CP MAS NMR experiments revealed the binding of the anionic sulfonate head group to the particle surface. The particles show bright red luminescence upon excitation of the aromatic capping agents, acting as antennas for an Energy transfer from the benzenesulfonate unit to the Eu3+ centers in the particles. This synthesis method overcomes the current obstacle of the fluorolytic sol-gel synthesis that transparent dispersions can be obtained directly only in hydrophilic solvents. To demonstrate the potential of such hydrophobized alkaline-earth fluoride particles, transparent luminescent organic-inorganic composites with 10% SrF2 :Eu3+ embedded into polyTEGDMA, polyBMA, poly-BDDMA and polyD3MA, respectively, were prepared, endowing the polymers with the luminescence features of the nanoparticles. KW - Nanoparticles KW - Fluorides KW - Sol-gel process KW - Organic-inorganic hybrid composites PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508668 DO - https://doi.org/10.1002/cnma.202000058 SP - 1 EP - 11 PB - Wiley AN - OPUS4-50866 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Biesen, L. A1 - Nirmalananthan-Budau, Nithiya A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Müller, T. J. J. T1 - Solid-State Emissive Aroyl-S,N-Ketene Acetals with Tunable N2 - N-Benzyl aroyl-S,N-ketene acetals can be readily synthesized by condensation of aroyl chlorides and N-Benzyl 2-methyl benzothiazolium salts in good to excellent yields, yielding a library of 35 chromophores with bright solid-state emission and aggregation-induced emission characteristics. Varying the substituent from electron-donating to electronwithdrawing enables the tuning of the solid-state emission Color from deep blue to red. KW - Nano KW - Nanoparticle KW - Photoluminescence KW - Fluorescence KW - Quantum yield KW - Photophysics KW - Lifetime KW - Sensor KW - dye KW - Enhancement KW - Particle KW - Polarity KW - AIE KW - Aggregation KW - Aggregation-induced emission KW - Solid state emission PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509072 DO - https://doi.org/10.1002/anie.201916396 VL - 59 IS - 25 SP - 10037 EP - 10041 PB - Wiley Online Libary AN - OPUS4-50907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Katrin A1 - Nirmalananthan-Budau, Nithiya A1 - Resch-Genger, Ute T1 - Fluorescence calibration standards made from broadband emitters encapsulated in polymer beads for fluorescence microscopy and flow cytometry N2 - We present here the design and characterization of a set of spectral calibration beads. These calibration beads are intended for the determination and regular control of the spectral characteristics of fluorescence microscopes and other fluorescence measuring devices for the readout of bead-based assays. This set consists of micrometer-sized polymer beads loaded with dyes from the liquid Calibration Kit Spectral Fluorescence Standards developed and certified by BAM for the wavelength-dependent Determination of the spectral responsivity of fluorescencemeasuring devices like spectrofluorometers. To cover the wavelength Region from 400 to 800 nm, two new near-infrared emissive dyes were included, which were spectroscopically characterized in solution and encapsulated in the beads. The resulting set of beads presents the first step towards a new platform of spectral calibration beads for the determination of the spectral characteristics of fluorescence instruments like fluorescence microscopes, FCM setups, and microtiter plate readers, thereby meeting the increasing demand for reliable and comparable fluorescence data especially in strongly regulated areas, e.g., medical diagnostics. This will eventually provide the basis for standardized calibration procedures for imaging systems as an alternative to microchannel slides containing dye solutions previously reported by us. KW - Fluorescence standard KW - Fluorescence KW - Dye KW - Microscopy KW - Bead KW - Particle KW - NIR KW - calibration KW - Quality assurance KW - Traceability PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508117 DO - https://doi.org/10.1007/s00216-020-02664-y SN - 1618-2642 VL - 412 IS - 24 SP - 6499 EP - 6507 PB - Springer AN - OPUS4-50811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kirilina, E. A1 - Helbling, S. A1 - Morawski, M. A1 - Pine, K. A1 - Reimann, K. A1 - Jankuhn, S. A1 - Dinse, J. A1 - Deistung, A. A1 - Reichenbach, J. R. A1 - Trampel, R. A1 - Geyer, S. A1 - Müller, Larissa A1 - Jakubowski, Norbert A1 - Arendt, T. A1 - Bazin, P.-L. A1 - Weiskopf, N. T1 - Superficial white matter imaging: Contrast mechanisms and whole-brain in vivo mapping N2 - Superficial white matter (SWM) contains the most cortico-cortical white matter connections in the human brain encompassing the short U-shaped association fibers. Despite its importance for brain connectivity, very little is known about SWM in humans, mainly due to the lack of noninvasive imaging methods. Here, we lay the groundwork for systematic in vivo SWM mapping using ultrahigh resolution 7 T magnetic resonance imaging. Using biophysical modeling informed by quantitative ion beam microscopy on postmortem brain tissue, we demonstrate that MR contrast in SWM is driven by iron and can be linked to the microscopic iron distribution. Higher SWM iron concentrations were observed in U-fiber–rich frontal, temporal, and parietal areas, potentially reflecting high fiber density or late myelination in these areas. Our SWM mapping approach provides the foundation for systematic studies of interindividual differences, plasticity, and pathologies of this crucial structure for cortico-cortical connectivity in humans. KW - Magnetic resonance imaging KW - Laser ablation KW - ICP-MS KW - Brain KW - Imaging PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514430 DO - https://doi.org/10.1126/sciadv.aaz9281 SN - 2375-2548 VL - 6 IS - 41 SP - eaaz9281 PB - American Association for the Advancement of Science (Science/AAAS) CY - Washington, DC, USA AN - OPUS4-51443 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neamtu, M. A1 - Nadejde, C. A1 - Brinza, L. A1 - Dragos, O. A1 - Gherghel, D. A1 - Paul, Andrea T1 - Iron phthalocyanine-sensitized magnetic catalysts for BPA photodegradation N2 - The catalytic behavior of iron phthalocyanine (FePc)-sensitized magnetic nanocatalysts was evaluated for their application in the oxidative treatment of Bisphenol A (BPA) under mild environmental conditions. Two types of FePc (Fe(II)Pc and Fe(III)Pc), which are highly photosensitive compounds, were immobilized on the surface of functionalized magnetite. The nanomaterials were characterized by high resolution transmission electron microscopy (HR-TEM), X-ray difraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA). The generation of singlet Oxygen by nanomaterials was also investigated. In the presence of UVA light exposure (365nm) and 15mM H2O2, the M@Fe(III)Pc photocatalyst gave the best results; for a catalyst concentration of 2.0gL −1, around 60% BPA was removed after 120min of reaction. These experimental conditions were further tested under natural solar light exposure, for which also M@Fe(III)Pc exhibited enhanced oxidative catalytic activity, being able to remove 83% of BPA in solution. The water samples were less cytotoxic after treatment, this being confrmed by the MCF-7 cell viability assay. KW - Photosensitization KW - magnetic nanocatalysts KW - BPA removal PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506368 DO - https://doi.org/10.1038/s41598-020-61980-6 VL - 10 IS - 1 SP - 5376 AN - OPUS4-50636 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmid, Thomas A1 - Jungnickel, Robert A1 - Dariz, P. T1 - Insights into the CaSO4–H2O System: A Raman-Spectroscopic Study N2 - Even though being the subject of natural scientific research for many decades, the system CaSO4–H2O, consisting of the five crystalline phases gypsum, bassanite, and the anhydrites III, II, and I, has left many open questions for research. Raman spectroscopy was used because of its structural sensitivity and in situ measurement capability to obtain further insight by studying phase transitions in both ex situ and in situ experiments. The findings include significant contributions to the completeness and understanding of Raman spectroscopic data of the system. The dehydration path gypsum–bassanite–anhydrite III was shown to have strong parallels to a physical drying process, which depends on many parameters beyond the burning temperature. Raman band width determination was demonstrated to enable the quantitative discrimination of α-bassanite and β-bassanite as well as the postulated three sub-forms of anhydrite II (AII), which are all based on differences in crystallinity. In the latter case, the observed continuous structural variations over increasing burning temperatures were elucidated as a combination of decreasing surface areas and healing of crystal lattice defects. We propose an only two-fold sub-division of AII into reactive “disordered AII” and much less reactive “crystalline AII” with a transition temperature of 650°C ± 50 K. KW - Gypsum KW - Bassanite KW - Hemihydrate KW - Anhydrite KW - Raman spectroscopy PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506701 DO - https://doi.org/10.3390/min10020115 SN - 2075-163X VL - 10 IS - 2 SP - 115, 35 PB - MDPI CY - Basel AN - OPUS4-50670 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zettner, Alina A1 - Gojani, Ardian A1 - Schmid, Thomas A1 - Gornushkin, Igor B. T1 - Evaluation of a Spatial Heterodyne Spectrometer for Raman Spectroscopy of Minerals N2 - Spatial heterodyne spectroscopy (SHS) is a novel spectral analysis technique that is being applied for Raman spectroscopy of minerals. This paper presents the theoretical basis of SHS and its application for Raman measurements of calcite, quartz and forsterite in marble, copper ore and nickel ore, respectively. The SHS measurements are done using a broadband (518–686 nm) and resolving power R ≈ 3000 instrument. The spectra obtained using SHS are compared to those obtained by benchtop and modular dispersive spectrometers. It is found that SHRS performance in terms of resolution is comparable to that of the benchtop spectrometer and better than the modular dispersive spectrometer, while the sensitivity of SHRS is worse than that of a benchtop spectrometer, but better than that of a modular dispersive spectrometer. When considered that SHS components are small and can be packaged into a handheld device, there is interest in developing an SHS-based Instrument for mobile Raman spectroscopy. This paper evaluates the possibility of such an application. KW - Forsterite KW - Spatial heterodyne spectrometer KW - Interferometric spectroscopy KW - Fourier transform spectroscopy KW - Raman spectroscopy KW - Calcite KW - Quartz PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504624 DO - https://doi.org/10.3390/min10020202 VL - 10 IS - 2 SP - 202 PB - MDPI CY - Basel, Switzerland AN - OPUS4-50462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ebel, Kenny A1 - Bald, Ilko T1 - Length and Energy Dependence of Low-Energy Electron-Induced Strand Breaks in Poly(A) DNA N2 - The DNA in living cells can be effectively damaged by high-energy radiation, which can lead to cell death. Through the ionization of water molecules, highly reactive secondary species such as low-energy electrons (LEEs) with the most probable energy around 10 eV are generated, which are able to induce DNA strand breaks via dissociative electron attachment. Absolute DNA strand break cross sections of specific DNA sequences can be efficiently determined using DNA origami nanostructures as platforms exposing the target sequences towards LEEs. In this paper, we systematically study the effect of the oligonucleotide length on the strand break cross section at various irradiation energies. The present work focuses on poly-adenine sequences (d(A4), d(A8), d(A12), d(A16), and d(A20)) irradiated with 5.0, 7.0, 8.4, and 10 eV electrons. Independent of the DNA length, the strand break cross section shows a maximum around 7.0 eV electron energy for all investigated oligonucleotides confirming that strand breakage occurs through the initial formation of negative ion resonances. When going from d(A4) to d(A16), the strand break cross section increases with oligonucleotide length, but only at 7.0 and 8.4 eV, i.e., close to the maximum of the negative ion resonance, the increase in the strand break cross section with the length is similar to the increase of an estimated geometrical cross section. For d(A20), a markedly lower DNA strand break cross section is observed for all electron energies, which is tentatively ascribed to a conformational change of the dA20 sequence. The results indicate that, although there is a general length dependence of strand break cross sections, individual nucleotides do not contribute independently of the absolute strand break cross section of the whole DNA strand. The absolute quantification of sequence specific strand breaks will help develop a more accurate molecular level understanding of radiation induced DNA damage, which can then be used for optimized risk estimates in cancer radiation therapy. KW - DNA origami KW - DNA radiation damage KW - DNA strand breaks KW - Low-energy electrons KW - Sequence dependence PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503563 DO - https://doi.org/10.3390/ijms21010111 VL - 21 IS - 1 SP - 1 EP - 11 PB - MDPI CY - Basel, Switzerland AN - OPUS4-50356 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tjaden, B. A1 - Lisec, Jan A1 - Schramm, A. T1 - N-Myc-induced metabolic rewiring creates novel therapeutic vulnerabilities in neuroblastoma N2 - N-Myc is a transcription factor that is aberrantly expressed in many tumor types and is often correlated with poor patient prognosis. Recently, several lines of evidence pointed to the fact that oncogenic activation of Myc family proteins is concomitant with reprogramming of tumor cells to cope with an enhanced need for metabolites during cell growth. These adaptions are driven by the ability of Myc proteins to act as transcriptional amplifiers in a tissue-of-origin specific manner. Here, we describe the effects of N-Myc overexpression on metabolic reprogramming in neuroblastoma cells. Ectopic expression of N-Myc induced a glycolytic switch that was concomitant with enhanced sensitivity towards 2-deoxyglucose, an inhibitor of glycolysis. Moreover, global metabolic profiling revealed extensive alterations in the cellular metabolome resulting from overexpression of N-Myc. Limited supply with either of the two main carbon sources, glucose or glutamine, resulted in distinct shifts in steady-state metabolite levels and significant changes in glutathione metabolism. Interestingly, interference with glutamine-glutamate conversion preferentially blocked proliferation of N-Myc overexpressing cells, when glutamine levels were reduced. Thus, our study uncovered N-Myc induction and nutrient levels as important metabolic master switches in neuroblastoma cells and identified critical nodes that restrict tumor cell proliferation. KW - Mass-Spectrometry KW - Cancer KW - MYCN PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507193 DO - https://doi.org/10.1038/s41598-020-64040-1 VL - 10 IS - 1 SP - 7157 AN - OPUS4-50719 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmid, Thomas A1 - Dariz, P. T1 - Editorial for the special issue "Modern Raman spectroscopy of minerals" N2 - Raman spectroscopy provides vibrational fingerprints of chemical compounds enabling their unambiguous identification. The assignment of Raman spectra to minerals is straightforward, if appropriate reference data is accessible. Modern couplings of Raman spectroscopy with microscopy (Raman microspectroscopy) merge the high structural specificity with down to sub-micrometre spatial resolution. This analytical tool has high potential not only in the identification of minerals from natural sources but also for studying the complex microstructure and mineral distribution of both ancient and modern man-made materials. In addition to the chemical identity of minerals, Raman spectra are affected by crystal orientations (varying relative Raman band intensities); (sub)stoichiometric compositional changes (e.g., in solid solution series), traces of foreign ions, strain (the latter three shifting Raman bands); and crystallinity (changing Raman band widths), enabling a comprehensive physico-chemical characterisation of minerals. Thus, Raman spectroscopy – including its in situ measurement capabilities – provides possibilities to study mineral paragenesis in both, natural and man-made samples at the micrometre scale. While in 1928 the first experimental evidence for inelastic light scattering was provided by C. V. Raman and K. S. Krishnan by using sunlight for excitation, filters for selecting the inelastically scattered light, and their eyes for detection (later, photographic plates for acquisition of spectra were employed), modern Raman spectrometers make use of laser excitation, dispersive spectrographs and charge coupled device (CCD) detection. This Special Issue includes technological developments and applications in the field of modern Raman spectroscopy of minerals in a broad sense, from natural mineral deposits and archaeological objects to inorganic phases in man-made materials. The studied minerals include fossil resins, typical rock-forming minerals (calcite, quartz, forsterite), iron-sulphur species (e.g., mackinawite), a range of sulphates (gypsum, bassanite, anhydrite III, anhydrite II, celestine, barite, ternesite), as well as silicate minerals like garnets (e.g., almandine). KW - Raman spectroscopy KW - Raman microspectroscopy KW - Mineral identification KW - Physico-chemical characterisation of minerals KW - Mineral paragenesis PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515041 DO - https://doi.org/10.3390/min10100860 VL - 10 SP - 860 PB - MDPI CY - Basel AN - OPUS4-51504 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rietsch, P. A1 - Sobottka, S. A1 - Hoffmann, K. A1 - Popov, A. A. A1 - Hildebrandt, P. A1 - Sarkar, B. A1 - Resch-Genger, Ute A1 - Eigler, S. T1 - Between Aromatic and Quinoid Structure: A Symmetrical UV to Vis/NIR Benzothiadiazole Redox Switch N2 - Reversibly switching the light absorption of organic molecules by redox processes is of interest for applications in sensors, light harvesting, smart materials, and medical diagnostics. This work presents a symmetrical benzothiadiazole (BTD) derivative with a high fluorescence quantum yield in solution and in the crystalline state and shows by spectroelectrochemical analysis that reversible switching of UV absorption in the neutral state, to broadband Vis/NIR absorption in the 1st oxidized state, to sharp band Vis absorption in the 2nd oxidized state, is possible. For the one-electron oxidized species, formation of a delocalized radical is confirmed by electron paramagnetic resonance spectroelectrochemistry. Furthermore, our results reveal an increasing quinoidal distortion upon the 1st and 2nd oxidation, which can be used as the leitmotif for the development of BTD based redox switches. KW - Dye KW - Electrochemistry KW - Switch KW - Redox KW - Sensor KW - Photophysics KW - Quantum yield KW - photoluminescence PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517222 DO - https://doi.org/10.1002/chem.202004009 VL - 26 IS - 72 SP - 17361 EP - 17365 PB - Wiley-VCH GmbH AN - OPUS4-51722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Resch-Genger, Ute A1 - Carl, F. A1 - Grauel, Bettina A1 - Pons, Monica A1 - Würth, Christian A1 - Haase, M. T1 - LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with luminescence decay times similar to YLF laser crystals and the upconversion quantum yield of the Yb,Er doped nanocrystals N2 - We developed a procedure to prepare luminescent LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with a size of approximately 40 nm revealing luminescence decay times of the dopant ions that approach those of high-quality laser crystals of LiYF4:Yb (Yb:YLF) and LiYF4:Yb,Er (Yb,Er:YLF) with identical doping concentrations. As the luminescence decay times of Yb3+ and Er3+ are known to be very sensitive to the presence of quenchers, the long decay times of the core/shell nanocrystals indicate a very low number of defects in the core particles and at the core/shell interfaces. This improvement in the performance was achieved by introducing two important modifications in the commonly used oleic acid based synthesis. First, the shell was prepared via anewly developed method characterized by a very low nucleation rate for particles of pure LiYF4 shell material. Second, anhydrous acetates were used as precursors and additional drying steps were applied to reduce the incorporation of OH− in the crystal lattice, known to quench the emission of Yb3+ ions. Excitation power density (P)-dependent absolute measurements of the upconversion luminescence quantum yield (Φ,UC) of LiYF4:Yb,Er/LiYF4 core/shell particles reveal a maximum value of 1.25% at P of 180 W·cm−2. Although lower than the values reported for NaYF4:18%Yb,2%Er core/shell nanocrystals with comparable sizes, these Φ, UC values are the highest reported so far for LiYF4:18%Yb,2%Er/LiYF4 nanocrystals without additional dopants. Further improvements May nevertheless be possible by optimizing the dopant concentrations in the LiYF4 nanocrystals. KW - Nano KW - Crystal KW - Quantum yield KW - LiYF4 KW - Synthesis KW - Lifetime KW - Fluorescence KW - NIR KW - Photoluminescence KW - Lanthanide KW - Upconversion nanoparticle KW - Nanomaterial PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515395 DO - https://doi.org/10.1007/s12274-020-3116-y SN - 1998-0124 VL - 14 IS - 3 SP - 797 EP - 806 PB - Springer AN - OPUS4-51539 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kage, Daniel A1 - Hoffmann, Katrin A1 - Borcherding, H. A1 - Schedler, U. A1 - Resch-Genger, Ute T1 - Lifetime encoding in flow cytometry for bead‑based sensing of biomolecular interaction N2 - To demonstrate the potential of time-resolved flow cytometry (FCM) for bioanalysis, clinical diagnostics, and optically encoded bead-based assays, we performed a proof-of-principle study to detect biomolecular interactions utilizing fluorescence lifetime (LT)-encoded micron-sized polymer beads bearing target-specific bioligands and a recently developed prototype lifetime flow cytometer (LT-FCM setup). This instrument is equipped with a single excitation light source and different fluorescence detectors, one operated in the photon-counting mode for time-resolved measurements of fluorescence decays and three detectors for conventional intensity measurements in different spectral windows. First, discrimination of bead-bound biomolecules was demonstrated in the time domain exemplarily for two targets, Streptavidin (SAv) and the tumor marker human chorionic gonadotropin (HCG). In a second step, the determination of biomolecule concentration levels was addressed representatively for the inflammation-related biomarker tumor necrosis factor (TNF-α) utilizing fluorescence intensity measurements in a second channel of the LT-FCM instrument. Our results underline the applicability of LT-FCM in the time domain for measurements of biomolecular interactions in suspension assays. In the future, the combination of spectral and LT encoding and multiplexing and the expansion of the time scale from the lower nanosecond range to the longer nanosecond and the microsecond region is expected to provide many distinguishable codes. This enables an increasing degree of multiplexing which could be attractive for high throughput screening applications. KW - Fluorescence KW - Sensor KW - Assay KW - Protein KW - Multiplexing KW - Flow cytometry KW - Barcoding KW - Lifetime KW - Dye KW - Bead KW - Bead-based assay KW - Method KW - Quantification PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516007 DO - https://doi.org/10.1038/s41598-020-76150-x VL - 10 IS - 1 SP - 19477 PB - Nature AN - OPUS4-51600 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bell, A. M. A1 - von der Au, Marcus A1 - Regnery, J. A1 - Schmid, M. A1 - Meermann, Björn A1 - Reifferscheid, G. A1 - Ternes, T. A1 - Buchinger, S. T1 - Does galvanic cathodic protection by aluminum anodes impact marine organisms? N2 - Background: Cathodic protection by sacrifcial anodes composed of aluminum-zinc-indium alloys is often applied to protect ofshore support structures of wind turbines from corrosion. Given the considerable growth of renewable energies and thus ofshore wind farms in Germany over the last decade, increasing levels of aluminum, Indium and zinc are released to the marine environment. Although these metals are ecotoxicologically well-studied, data regarding their impact on marine organisms, especially sediment-dwelling species, as well as possible ecotoxicological efects of galvanic anodes are scarce. To investigate possible ecotoxicological efects to the marine environment, the diatom Phaedactylum tricornutum, the bacterium Aliivibrio fscheri and the amphipod Corophium volutator were exposed to dissolved galvanic anodes and solutions of aluminum and zinc, respectively, in standardized laboratory tests using natural seawater. In addition to acute toxicological efects, the uptake of these elements by C. volutator was investigated. Results: The investigated anode material caused no acute toxicity to the tested bacteria and only weak but signifcant efects on algal growth. In case of the amphipods, the single elements Al and Zn showed signifcant efects only at the highest tested concentrations. Moreover, an accumulation of Al and In was observed in the crustacea species. Conclusions: Overall, the fndings of this study indicated no direct environmental impact on the tested marine organisms by the use of galvanic anodes for cathodic protection. However, the accumulation of metals in, e.g., crustaceans might enhance their trophic transfer within the marine food web. KW - Galvanic anodes KW - Metal toxicity KW - Metal uptake KW - Corophium volutator KW - Seawater PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520769 DO - https://doi.org/10.1186/s12302-020-00441-3 VL - 32 IS - 1 SP - Article number 157 AN - OPUS4-52076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -