TY - JOUR A1 - Grabolle, Markus A1 - Brehm, Robert A1 - Pauli, Jutta A1 - Dees, F.M. A1 - Hilger, I. A1 - Resch-Genger, Ute T1 - Determination of the labeling density of fluorophore-biomolecule conjugates with absorption spectroscopy N2 - Dye–biomolecule conjugation is frequently accompanied by considerable spectral changes of the dye’s absorption spectrum that limit the use of the common photometrical method for the determination of labeling densities. Here, we describe an improvement of this method using the integral absorbance of the dye instead of its absorbance at the long wavelength maximum to determine the concentration of the biomolecule-coupled dye. This approach is illustrated for three different cyanine dyes conjugated to the antibody IgG. KW - Fluorescent dye KW - Aggregation KW - Dimerization KW - Fluorophore-labeled antibodies KW - Labeling density KW - Dye-to-protein ratio KW - Absorption PY - 2012 DO - https://doi.org/10.1021/bc2003428 SN - 1043-1802 SN - 1520-4812 VL - 23 IS - 2 SP - 287 EP - 292 CY - Washington, DC AN - OPUS4-25527 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fleige, E. A1 - Ziem, B. A1 - Grabolle, Markus A1 - Haag, R. A1 - Resch-Genger, Ute T1 - Aggregation phenomena of host and guest upon the loading of dendritic core-multishell nanoparticles with solvatochromic dyes N2 - We systematically assessed the loading behavior of core-multishell nanoparticles (CMS NPs) for the solvatochromic dyes Coumarin 153 and Nile Red and studied the influence of the guest and its concentration on CMS NP aggregation using steady state absorption and fluorescence spectroscopy and dynamic light scattering (DLS). These measurements revealed the strong fluorescence of dye-loaded CMS NPs and formation of nonemissive dye aggregates in the outer CMS layer at higher loading concentrations of Nile Red, whereas in the case of Coumarin 153, a new species with red-shifted absorption and blue-shifted emission appeared. Moreover, dye loading triggers an aggregation of CMS NPs which have a hydrodynamic radius of 8 nm, thereby leading to CMS aggregates with a radius of 100–120 nm. These results underline the need for systematic studies of the influence of the guest and its loading concentration on CMS NP size for cellular uptake and in vivo imaging studies and the rational design of CMS NPs with improved transport and targeting abilities. PY - 2012 DO - https://doi.org/10.1021/ma301977r SN - 0024-9297 SN - 1520-5835 VL - 45 IS - 23 SP - 9452 EP - 9459 PB - American Chemical Society CY - Washington, DC AN - OPUS4-27592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reisgen, U. A1 - Schleser, M. A1 - Abdurakhmanov, A. A1 - Gumenyuk, Andrey T1 - Measuring of plasma properties induced by non-vacuum electron beam welding N2 - Electron beam plasma measurement was realised by means of DIABEAM system invented by ISF RWTH Aachen. The Langmuir probe method is used for measurement. The relative simplicity of the method and the possibility of dispersion of high power on the probe allow its application for the investigation of high-power electron beams. The key element of the method is a rotating thin tungsten wire, which intersects the beam transversely on its axis and collects part of the current by itself. The signals, which are registered in the DIABEAM as a voltage, were taken in the form of amplitude. The conversion of the probe current into the distribution along the beam radius was realised using the Abel's method. A voltage-current characteristic was built for the beam current. The local electron density as well as the electron temperature, the floating potential and the plasma potential were measured and calculated by means of this characteristic. KW - Plasma KW - Diagnostic KW - Welding PY - 2012 DO - https://doi.org/10.1063/1.3675874 SN - 1070-664X VL - 19 SP - 0131006-1 EP - 0131006-7 PB - American Institute of Physics CY - Melville, NY, USA AN - OPUS4-25474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kato, K. A1 - Watanabe, T. A1 - Heine, Hans-Joachim A1 - Boissière, Claudia A1 - Schulz, Gert A1 - Woo, J.-C. A1 - Kim, J.S. A1 - Sang-Hyub, O. A1 - Bae, H. K. A1 - Kim, Y.D. A1 - Qiao, H. A1 - Guenther, F.R. A1 - Roderick, G. C. A1 - Miller, W. A1 - Smeulders, D. A1 - Botha, A. A1 - van Rensburg, M.J. A1 - Tshilongo, J. A1 - Leshabane, N. A1 - Ntsasa, N. A1 - Milton, M. A1 - Vargha, G. A1 - Harling, A. A1 - Konopelko, L. A1 - Kustikov, Y.A. A1 - Vasserman, I.I. A1 - Zavyalov, S. V. A1 - Popova, T.A. A1 - Pankratov, V.V. A1 - Pir, M.N. A1 - Maltsev, M.A. A1 - Oudwater, R. A1 - Persijn, S. A1 - van Wijk, J. A1 - Wessel, R. M. T1 - International comparison CCQM-K66: Impurity analysis of methane N2 - This key comparison was performed to demonstrate the capability of NMIs to analyse the purity of methane for use as a source gas in the preparation of standard gas mixtures. This capability is an essential requirement for the preparation of accurate standards of natural gas and some other fuels. Since it is difficult to carry out a comparison with individual samples of pure gas, the sample for this comparison was a synthetic mixture of high purity methane with selected added impurities of nitrogen, argon, carbon dioxide and ethane. These mixtures were prepared by a gas company as a batch of 10 cylinders and their homogeneity and stability were evaluated by NMIJ. The KCRVs for the four different analytes in this key comparison are based on a consensus of values reported by participants. The uncertainties in the degrees of equivalence were calculated by combining the reported uncertainties with the homogeneity of the samples and the uncertainty of the KCRV. The results submitted are generally consistent with the KCRV within the estimated uncertainties. Finally, this comparison demonstrates that the analysis of nitrogen, argon, carbon dioxide and ethane in methane at amount fractions of 1 µmol/mol to 5 µmol/mol is generally possible with an uncertainty of 5% to 10%. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA). DatesIssue 1A (Technical Supplement 2012) KW - Ringversuch KW - Methan KW - Spurenverunreinigungen KW - Gaschromatographie PY - 2012 DO - https://doi.org/10.1088/0026-1394/49/1A/08001 SN - 0026-1394 SN - 1681-7575 VL - 49 IS - 08001 SP - 1 EP - 76 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-25929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lange, T. A1 - Heinrich, Sebastian A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Klemm, E. T1 - Reaction engineering investigations of the heterogeneously catalyzed partial oxidation of o-xylene in the explosion regime using a microfixed bed reactor N2 - The heterogeneously catalyzed selective gas phase oxidation of o-xylene was investigated, using a microstructured fixed bed reactor, inside of the explosion regime. The reaction was carried out with high amounts of o-xylene in air and stoichiometric with oxygen using a V2O5/TiO2-catalyst prepared through grafting. There were no significant losses in the selectivity to phthalic anhydride observable, during the measurements in the explosion regime, with feed compositions of up to 7 vol% o-xylene. Also the space-time yield was up to 2.3 times higher in comparison to conventional reaction conditions. An increase of the selectivity to total oxidation products was observed at higher o-xylene concentrations between 10 and 25 vol% o-xylene, which possibly was caused by the formation of a hotspot. The investigation of the used catalyst revealed a thermally induced deactivation due to phase transition of anatase into rutil and formation of crystalline vanadium oxide. Despite that expected hotspot at high oxylene concentrations, there was no ignition or explosion of the gas mixture observable. KW - O-xylene oxidation KW - Phthalic anhydride KW - V2O5/TiO2-catalyst KW - Microfixed bed reactor KW - Explosion regime KW - Hotspot PY - 2012 DO - https://doi.org/10.1016/j.ces.2011.10.072 SN - 0009-2509 VL - 69 IS - 1 SP - 440 EP - 448 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-25463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fayis Kalady, Mohammed A1 - Schultz, Johannes A1 - Weinel, Kristina A1 - Wolf, Daniel A1 - Lubk, Axel T1 - Geometry-dependent localization of surface plasmons on random gold nanoparticle assemblies N2 - Assemblies of plasmonic nanoparticles (NPs) support hybridized modes of localized surface plasmons (LSPs), which delocalize in geometrically well-ordered arrangements. Here, the hybridization behavior of LSPs in geometrically completely disordered two-dimensional arrangements of Au NPs fabricated by an e-beam synthesis method is studied. Employing electron energy loss spectroscopy in a scanning transmission electron microscope and numerical simulations, the disorder-driven spatial and spectral localization of the coupled LSP modes that depends on the NP thickness is revealed. Below a NP thickness of 0.4 nm, localization increases toward higher hybridized LSP mode energies. In comparison, above 10 nm thickness, a decrease of localization toward higher mode energies is observed. In the intermediate thickness regime, a transition of the energy dependence of the localization between the two limiting cases, exhibiting a mode energy with minimal localization, is observed. It is shown that this behavior is mainly driven by the energy and thickness dependence of the polarizability of the individual NPs. KW - Gold Nanoparticles KW - Surface plasmons KW - Electron enerdy loss spectroscopy (EELS) KW - scanning transmission electron microscopy PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647230 DO - https://doi.org/10.1103/44nk-6bp2 SN - 2643-1564 VL - 7 IS - 043053 EP - 4 PB - American Physical Society AN - OPUS4-64723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinrich, Hans-Joachim A1 - Kipphardt, Heinrich T1 - Application of methane as a gaseous modifier for the determination of silicon using electrothermal atomic absorption spectrometry N2 - For determination of silicon in aqueous solutions by electrothermal atomic absorption spectrometry methane/argon mixtures as a gaseous modifier were applied during the pyrolysis step to improve the analytical performance. The beneficial effects observed on thermal stabilization, signal enhancement and shape of absorbance signals were attributed to the thermal decomposition products of methane, which were hydrogen and carbon black (soot). Using a 5% CH4 mixture with argon, the optimized pyrolysis and atomization temperatures were 1350 °C and 2450 °C, respectively. A flushing step following the pyrolysis was mandatory to avoid background absorption and accelerated deposition of pyrolytic graphite. Characteristic masses of 50 and 30 pg were obtained for standard transversely heated graphite atomizer (THGA) tubes and end-capped THGA tubes, respectively, which were lower than with other previously applied modifiers. A limit of detection of 0.2 µg L- 1 (3 s, n = 10) has been obtained. In addition, this gaseous modifier did not contribute to contamination which often was significant when a liquid modifier solution was co-injected. The proposed method has been applied to the determination of silicon in ultrapure water, nitric and hydrochloric acids. KW - Electrothermal atomic absorption KW - Spectrometry KW - Silicon determination KW - Methane KW - Modifier KW - Ultrapure reagents PY - 2012 DO - https://doi.org/10.1016/j.sab.2012.04.001 SN - 0584-8547 SN - 0038-6987 VL - 70 SP - 68 EP - 73 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-26050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinrich, Sebastian A1 - Edeling, Florian A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Lange, T. A1 - Klemm, E. T1 - Catalyst as ignition source of an explosion inside a microreactor N2 - The present issue reports on a specific aspect of safety engineering of the heterogeneously catalysed oxidation of ethene in a continuous-flow microreactor. Conversion of ethene and the corresponding surface temperature of the catalyst were monitored for different reactor temperatures and total flow rates with a stoichiometric ethene/oxygen mixture for total oxidation. Safe operation of the highly exothermic oxidation was possible, but not in the whole parameter range. At high reactor temperatures and flow rates, ignition of an explosion inside the microreactor caused by a hot spot on the surface of the catalyst was observed for the first time. KW - Catalyst KW - Ethene KW - Explosions KW - Hot spot KW - Microstructure KW - Safety PY - 2012 DO - https://doi.org/10.1016/j.ces.2012.08.049 SN - 0009-2509 VL - 84 SP - 540 EP - 543 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-26782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hickel, Tilmann A1 - Waske, Anja A1 - Tehranchi, Ali A1 - Bhattacharya, Biswajit A1 - Stawski, Tomasz M. A1 - Fellinger, Tim-Patrick A1 - Mehmood, Asad A1 - Witt, Julia A1 - Ozcan, Ozlem A1 - Guilherme Buzanich, Ana A1 - Kumar, Sourabh A1 - Mishra, Rajesh Kumar A1 - Holzer, Marco A1 - Stucchi de Camargo, Andrea Simone A1 - Agudo Jácome, Leonardo A1 - Manzoni, Anna A1 - Fantin, Andrea A1 - John, Elisabeth A1 - Hodoroaba, Vasile-Dan A1 - Bührig, Sophia A1 - Murugan, Jegatheesan A1 - Marschall, Niklas A1 - George, Janine A1 - Darvishi Kamachali, Reza A1 - Maaß, Robert A1 - Emmerling, Franziska T1 - Chemically complex materials enable sustainable high-performance materials N2 - Chemically complex materials (CCMats) 􀀀 including high-entropy alloys, oxides, and related multi-principal element systems 􀀀 offer a paradigm shift in materials design by leveraging chemical diversity to simultaneously optimize functional, structural, and sustainability criteria. The vastness of the compositional and structural space in CCMats propels the field into an expanding exploratory state. To reconcile functional and structural performance across this immense parameter space remains an open challenge. This Perspective evaluates the opportunities and challenges associated with harnessing chemical complexity across a broad spectrum of applications, such as hydrogen storage, ionic conductors, catalysis, magnetics, dielectrics, semiconductors, optical materials, and multifunctional structural systems. It is delineated how three central design strategies: targeted substitution (SUB), defect engineering (DEF), and diversity management (DIV) enable the reconciliation of high functional performance with long-term structural stability and environmental responsibility. Advances in computational thermodynamics, microstructure simulations, machine learning, and multimodal characterization are accelerating the exploration and optimization of CCMats, while robust data infrastructures and automated synthesis workflows are emerging as essential tools for navigating their complex compositional space. By fostering cross-disciplinary knowledge transfer and embracing data-driven design, CCMats are poised to deliver next-generation materials solutions that address urgent technological, energy, and environmental demands. KW - Chemically complex materials KW - Structural stability KW - Functional performance KW - Design strategies KW - Sustainability PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655598 UR - https://www.sciencedirect.com/science/article/pii/S1359028626000033?via%3Dihub DO - https://doi.org/10.1016/j.cossms.2026.101256 SN - 1359-0286 VL - 42 SP - 1 EP - 26 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-65559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Harrer, Andrea A1 - Daschewski, Maxim A1 - Prager, Jens A1 - Kreutzbruck, Marc A1 - Guderian, Matthias A1 - Meyer-Plath, Asmus T1 - Thermoacoustic generation of airborne ultrasound using carbon materials at the micro- and nanoscale N2 - The generation of airborne ultrasound is presented using the thermoacoustic principle applied to carbon materials at the micro- and nanoscale. Such materials are shown to be capable of emitting ultrasound when being fed by an alternating current. We tested the acoustic performance of carbon fibers, bucky papers and electrospun polyacrylonitrile-derived carbon nanofibers and determined the sound pressure for frequencies up to 350 kHz. A comparison between the experimental results and the theoretical prediction showed remarkable agreement for frequencies up to 150 kHz. Beyond 150 kHz, we found slight deviations from the expected sound pressure dependence on the square root of the frequency. KW - Thermoacoustic KW - Airborne ultrasound transducer KW - Sound pressure PY - 2012 DO - https://doi.org/10.3233/JAE-2012-1440 SN - 1383-5416 SN - 0925-2096 VL - 39 IS - 1-4 SP - 35 EP - 41 PB - IOS Press CY - Amsterdam, The Netherlands AN - OPUS4-26737 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -