TY - JOUR A1 - Faghani, A. A1 - Gholami, M. F. A1 - Trunk, M. A1 - Müller, J. A1 - Pachfule, P. A1 - Vogl, S. A1 - Donskyi, Ievgen A1 - Li, M. A1 - Nickl, Philip A1 - Shao, J. A1 - Huang, M. R. S. A1 - Unger, Wolfgang A1 - Arenal, R. A1 - Koch, C. T. A1 - Paulus, B. A1 - Rabe, J. P. A1 - Thomas, A. A1 - Haag, R. A1 - Adeli, M. T1 - Metal-Assisted and Solvent-Mediated Synthesis of Two-Dimensional Triazine Structures on Gram Scale N2 - Covalent triazine frameworks are an emerging material class that have shown promising performance for a range of applications. In this work, we report on a metal-assisted and solvent-mediated reaction between calcium carbide and cyanuric chloride, as cheap and commercially available precursors, to synthesize two-dimensional triazine structures (2DTSs). The reaction between the solvent, dimethylformamide, and cyanuric chloride was promoted by calcium carbide and resulted in dimethylamino-s-triazine intermediates, which in turn undergo nucleophilic substitutions. This reaction was directed into two dimensions by calcium ions derived from calcium carbide and induced the formation of 2DTSs. The role of calcium ions to direct the two-dimensionality of the final structure was simulated using DFT and further proven by synthesizing molecular intermediates. The water content of the reaction medium was found to be a crucial factor that affected the structure of the products dramatically. While 2DTSs were obtained under anhydrous conditions, a mixture of graphitic material/2DTSs or only graphitic material (GM) was obtained in aqueous solutions. Due to the straightforward and gram-scale synthesis of 2DTSs, as well as their photothermal and photodynamic properties, they are promising materials for a wide range of future applications, including bacteria and virus incapacitation. KW - XPS KW - Triazine KW - 2D PY - 2020 DO - https://doi.org/10.1021/jacs.0c02399 VL - 142 IS - 30 SP - 12976 EP - 12986 PB - ACS American Chemical Society AN - OPUS4-51203 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abou-Ras, D. A1 - Caballero, R. A1 - Fischer, C.-H. A1 - Kaufmann, C.A. A1 - Lauermann, I. A1 - Mainz, R. A1 - Mönig, H. A1 - Schöpke, A. A1 - Stephan, C. A1 - Streeck, C. A1 - Schorr, S. A1 - Eicke, A. A1 - Döbeli, M. A1 - Gade, B. A1 - Hinrichs, J. A1 - Nunney, T. A1 - Dijkstra, H. A1 - Hoffmann, V. A1 - Klemm, D. A1 - Efimova, V. A1 - Bergmaier, A. A1 - Dollinger, G. A1 - Wirth, Thomas A1 - Unger, Wolfgang A1 - Rockett, A.A. A1 - Perez-Rodriguez, A. A1 - Alvarez-Garcia, J. A1 - Izquierdo-Roca, V. A1 - Schmid, T. A1 - Choi, P.-P. A1 - Müller, M. A1 - Bertram, F. A1 - Christen, J. A1 - Khatri, H. A1 - Collins, R.W. A1 - Marsillac, S. A1 - Kötschau, I. T1 - Comprehensive comparison of various techniques for the analysis of elemental distributions in thin films N2 - The present work shows results on elemental distribution analyses in Cu(In,Ga)Se2 thin films for solar cells performed by use of wavelength-dispersive and energy-dispersive X-ray spectrometry (EDX) in a scanning electron microscope, EDX in a transmission electron microscope, X-ray photoelectron, angle-dependent soft X-ray emission, secondary ion-mass (SIMS), time-of-flight SIMS, sputtered neutral mass, glow-discharge optical emission and glow-discharge mass, Auger electron, and Rutherford backscattering spectrometry, by use of scanning Auger electron microscopy, Raman depth profiling, and Raman mapping, as well as by use of elastic recoil detection analysis, grazing-incidence X-ray and electron backscatter diffraction, and grazing-incidence X-ray fluorescence analysis. The Cu(In,Ga)Se2 thin films used for the present comparison were produced during the same identical deposition run and exhibit thicknesses of about 2 µm. The analysis techniques were compared with respect to their spatial and depth resolutions, measuring speeds, availabilities, and detection limits. KW - Elemental distributions KW - Comparison KW - Depth profiling KW - Chemical mapping KW - Thin films KW - Solar cells KW - Chalcopyrite-type KW - Cu(In,Ga)Se2 PY - 2011 DO - https://doi.org/10.1017/S1431927611000523 SN - 1431-9276 SN - 1435-8115 VL - 17 IS - 5 SP - 728 EP - 751 PB - Cambridge University Press CY - New York, NY AN - OPUS4-24506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Moritz, W. A1 - Werner, R. A1 - Tausche, A. A1 - Cherkaschinin, G. A1 - Molajew, R. A1 - Wirth, Thomas A1 - Unger, Wolfgang A1 - Linke, S. T1 - Alloys for gas sensors investigated using the continuous gradient-high throughput screening macroscope CG-HTSM N2 - Ternary alloys have been studied as the gate metal of chemical sensors based on the field effect in silicon. The investigation of reduced poisoning of hydrogen sensors by H2S is presented in the alloy system PdxNiyCo1-x-y. A new method in high throughput screening of alloys is applied. Not singular sample compositions but a continuous gradient in alloy concentrations was produced on a semiconductor sample. A laser scanning system produces a photo current in the semiconductor to map the sensor signal and provide a quasi continuous alloy characterization. The new system is therefore called Continuous Gradient—High Throughput Screening Macroscope (CG-HTSM). Typically 625 alloys are characterized in 15 minutes. The resolution of our set-up allows distinguishing 100.000 alloy compositions. KW - Alloy KW - Sensor KW - High throughput screening KW - Macroscope PY - 2011 DO - https://doi.org/10.1166/sl.2011.1586 SN - 1546-198X SN - 1546-1971 VL - 9 IS - 2 SP - 662 EP - 664 PB - American Scientific Publishers (ASP) CY - Stevenson Ranch, CA, USA AN - OPUS4-24504 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rouquerol, J. A1 - Baron, G. A1 - Denoyel, R. A1 - Giesche, H. A1 - Groen, J. A1 - Klobes, Peter A1 - Levitz, P. A1 - Neimark, A.V. A1 - Rigby, S. A1 - Skudas, R. A1 - Sing, K. A1 - Thommes, M. A1 - Unger, K. T1 - Liquid intrusion and alternative methods for the characterization of macroporous materials (IUPAC technical report) N2 - This document deals with the characterization of porous materials having pore widths in the macropore range of 50 nm to 500 µm. In recent years, the development of advanced adsorbents and catalysts (e.g., monoliths having hierarchical pore networks) has brought about a renewed interest in macropore structures. Mercury intrusion–extrusion porosimetry is a well-established method, which is at present the most widely used for determining the macropore size distribution. However, because of the reservations raised by the use of mercury, it is now evident that the principles involved in the application of mercury porosimetry require reappraisal and that alternative methods are worth being listed and evaluated. The reliability of mercury porosimetry is discussed in the first part of the report along with the conditions required for its safe use. Other procedures for macropore size analysis, which are critically examined, include the intrusion of other non-wetting liquids and certain wetting liquids, capillary condensation, liquid permeation, imaging, and image analysis. The statistical reconstruction of porous materials and the use of macroporous reference materials (RMs) are also examined. Finally, the future of macropore analysis is discussed. KW - Capillary condensation KW - Image analysis KW - IUPAC physical and biophysical chemistry division KW - Liquid intrusion KW - Macroporous materials KW - Mercury prorsimetry KW - Permeation KW - Pore size characterization KW - Reference porous materials KW - Statistical reconstruction of porous solids PY - 2012 DO - https://doi.org/10.1351/PAC-REP-10-11-19 SN - 0033-4545 SN - 1365-3075 VL - 84 IS - 1 SP - 107 EP - 136 PB - Union CY - Research Triangle Park, NC AN - OPUS4-26109 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kasper, J. A1 - Hermanns, M. A1 - Bantz, C. A1 - Maskos, Michael A1 - Stauber, R. A1 - Pohl, C. A1 - Unger, R. E. A1 - Kirkpatrick, J.C. T1 - Inflammatory and cytotoxic responses of an alveolar-capillary coculture model to silica nanoparticles: comparison with conventional monocultures N2 - To date silica nanoparticles (SNPs) play an important role in modern technology and nanomedicine. SNPs are present in various materials (tyres, electrical and thermal insulation material, photovoltaic facilities). They are also used in products that are directly exposed to humans such as cosmetics or toothpaste. For that reason it is of great concern to evaluate the possible hazards of these engineered particles for human health. Attention should primarily be focussed on SNP effects on biological barriers. Accidentally released SNP could, for example, encounter the alveolar-capillary barrier by inhalation. In this study we examined the inflammatory and cytotoxic responses of monodisperse amorphous silica nanoparticles (aSNPs) of 30 nm in size on an in vitro coculture model mimicking the alveolar-capillary barrier and compared these to conventional monocultures. Methods Thus, the epithelial cell line, H441, and the endothelial cell line, ISO-HAS-1, were used in monoculture and in coculture on opposite sides of a filter membrane. Cytotoxicity was evaluated by the MTS assay, detection of membrane integrity (LDH release), and TER (Transepithelial Electrical Resistance) measurement. Additionally, parameters of inflammation (sICAM-1, IL-6 and IL-8 release) and apoptosis markers were investigated. Results Regarding toxic effects (viability, membrane integrity, TER) the coculture model was less sensitive to apical aSNP exposure than the conventional monocultures of the appropriate cells. On the other hand, the in vitro coculture model responded with the release of inflammatory markers in a much more sensitive fashion than the conventional monoculture. At concentrations that were 10-100fold less than the toxic concentrations the apically exposed coculture showed a release of IL-6 and IL-8 to the basolateral side. This may mimic the early inflammatory events that take place in the pulmonary alveoli after aSNP inhalation. Furthermore, a number of apoptosis markers belonging to the intrinsic pathway were upregulated in the coculture following aSNP treatment. Analysis of the individual markers indicated that the cells suffered from DNA damage, hypoxia and ER-stress. Conclusion We present evidence that our in vitro coculture model of the alveolar-capillary barrier is clearly advantageous compared to conventional monocultures in evaluating the extent of damage caused by hazardous material encountering the principle biological barrier in the lower respiratory tract. KW - Silica nanoparticles KW - Alveolar-capillary coculture model KW - Cytotoxicity PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-254217 DO - https://doi.org/10.1186/1743-8977-8-6 SN - 1743-8977 VL - 8 IS - 6 SP - 1 EP - 16(?) PB - BioMed Central CY - London AN - OPUS4-25421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tu, Z. A1 - Donskyi, Ievgen A1 - Qiao, H. A1 - Zhu, Z. A1 - Unger, Wolfgang A1 - Hackenberger, C. P. R. A1 - Chen, W. A1 - Adeli, M. A1 - Haag, R. T1 - Graphene Oxide-Cyclic R10 Peptide Nuclear Translocation Nanoplatforms for the Surmounting of Multiple-Drug Resistance N2 - Multidrug resistance resulting from a variety of defensive pathways in Cancer has become a global concern with a considerable impact on the mortality associated with the failure of traditional chemotherapy. Therefore, further research and new therapies are required to overcome this challenge. In this work, a cyclic R10 peptide (cR10) is conjugated to polyglycerol-covered nanographene oxide to engineer a nanoplatform for the surmounting of multidrug resistance. The nuclear translocation of the nanoplatform, facilitated by cR10 peptide, and subsequently, a laser-triggered release of the loaded doxorubicin result in efficient anticancer activity confirmed by both in vitro and in vivo experiments. The synthesized nanoplatform with a combination of different features, including active nucleus-targeting, highloading capacity, controlled release of cargo, and photothermal property, provides a new strategy for circumventing multidrug resistant cancers. KW - Graphen Oxide KW - Nanoplatform KW - Cancer PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510061 DO - https://doi.org/10.1002/adfm.202000933 VL - 30 IS - 35 SP - 2000933 PB - Wiley VCH AN - OPUS4-51006 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Unger, R. A1 - Braun, Ulrike A1 - Fankhänel, J. A1 - Daum, B. A1 - Arash, B. A1 - Rolfes, R. T1 - Molecular modelling of epoxy resin crosslinking experimentally validated by near-infrared spectroscopy N2 - Reliable simulation of polymers on an atomistic length scale requires a realistic representation of the cured material. A molecular modelling method for the curing of epoxy systems is presented, which is developed with respect to efficiency while maintaining a well equilibrated system. The main criterion for bond formation is the distance between reactive groups and no specific reaction probability is prescribed. The molecular modelling is studied for three different mixing ratios with respect to the curing evolution of reactive Groups and the final curing stage. For the first time, the evolution of reactive groups during the curing process predicted by the molecular modelling is validated with near-infrared spectroscopy data, showing a good agreement between simulation results and experimental measurements. With the proposed method, deeper insights into the curing mechanism of epoxy systems can be gained and it allows us to provide reliable input data for molecular Dynamics simulations of material properties. KW - Epoxy KW - NIR spectroscopy KW - Modelling PY - 2019 DO - https://doi.org/10.1016/j.commatsci.2019.01.054 SN - 0927-0256 VL - 161 SP - 223 EP - 235 PB - Elsevier AN - OPUS4-47431 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ahmed, R. A1 - Vaishampayan, A. A1 - Cuellar-Camacho, J. L. A1 - Wight, D. J. A1 - Donskyi, Ievgen A1 - Unger, Wolfgang A1 - Grohmann, E. A1 - Haag, R. A1 - Wagner, O. T1 - Multivalent Bacteria Binding by Flexible Polycationic Microsheets Matching Their Surface Charge Density N2 - Aiming at the overall negative surface charge of bacteria, a new strategy of antibacterial agents based on large polymer-modified graphene oxide (GO) sheets is assessed. The presented flexible, polycationic Sheets match the size and charge density of the Escherichia coli surface charge density (2 × 1014 cm−2). These matching parameters create an unspecific but very strong bacteria adsorber by multivalent, electrostatic attraction. Their interaction with bacteria is visualized via atomic force and confocal microscopy and shows that they effectively bind and wrap around E. coli cells, and thereby immobilize them. The incubation of Gram-negative and -positive bacteria (E. coli and methicillin-resistant Staphylococcus aureus, MRSA) with these polycationic sheets leads to the inhibition of proliferation and a reduction of the colony forming bacteria over time. This new type of antibacterial agent acts in a different mode of Action than classical biocides and could potentially be employed in medicinal, technical, or agriculture applications. The presented microsheets and their unspecific binding of cell interfaces could further be employed as adsorber material for bacterial filtration or immobilization for imaging, analysis, or sensor technologies. KW - Surface charge KW - Bacteria KW - Graphene oxide KW - Escherichia coli KW - XPS PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509651 DO - https://doi.org/10.1002/admi.201902066 VL - 7 IS - 15 SP - 1902066 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-50965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Holzweber, Markus A1 - Lippitz, Andreas A1 - Hesse, R. A1 - Denecke, R. A1 - Werner, W. A1 - Unger, Wolfgang T1 - The use of ionic liquids for the determination of the spectrometer transmission function in X-ray photoelectron spectroscopy (XPS) N2 - The uncertainty of measurement in quantitative XPS analysis can be reduced by using a calibrated spectrometer transmission function T (E), which is usually determined by taking spectra from Au, Ag, Cu and Ge elemental reference materials. However, this approach is quite time-consuming due to required sample preparation steps like sputter cleaning etc., and the relatively big number of samples to be measured. This contribution proposes the use of the ionic liquids [C2C1im][NTf2] and [C3C1im][NTf2] as reference materials for a determination of T(E). These multi-elemental samples deliver five intensive photoemission peaks, F 1s, O 1s, N 1s, C 1s and S 2p, in an energy window from 160 eV to 700 eV which is of specific interest for applications of quantitative XPS for surface chemical analysis of soft matter, one of the major applications of XPS. KW - Quantitative XPS KW - Ionic liquid KW - Transmission function PY - 2019 DO - https://doi.org/10.1016/j.elspec.2019.03.008 VL - 233 SP - 51 EP - 56 PB - Elsevier B.V. AN - OPUS4-48019 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kim, K.J. A1 - Jang, J. S. A1 - Kim, A. S. A1 - Suh, J.K. A1 - Chung, Y.-D. A1 - Hodoroaba, Vasile-Dan A1 - Wirth, Thomas A1 - Unger, Wolfgang A1 - Kang, H. J. A1 - Popov, O. A1 - Popov, I. A1 - Kuselman, I. A1 - Lee, Y. H. A1 - Sykes, D. E. A1 - Wang, M. A1 - Wang, H. A1 - Ogiwara, T. A1 - Nishio, M. A1 - Tanuma, S. A1 - Simons, D. A1 - Szakal, C. A1 - Osborn, W. A1 - Terauchi, S. A1 - Ito, M. A1 - Kurokawa, A. A1 - Fujiimoto, T. A1 - Jordaan, W. A1 - Jeong, C. S. A1 - Havelund, R. A1 - Spencer, S. A1 - Shard, A. A1 - Streeck, C. A1 - Beckhoff, B. A1 - Eicke, A. A1 - Terborg, R. T1 - CCQM pilot study P-140: Quantitative surface analysis of multi-element alloy films N2 - A pilot study for the quantitative surface analysis of multi-element alloy films has been performed by the Surface Analysis Working Group (SAWG) of the Consultative Committee for Amount of Substance (CCQM). The aim of this pilot study is to ensure the equivalency in the measurement capability of national metrology institutes for the quantification of multi-element alloy films. A Cu(In,Ga)Se2 (CIGS) film with non-uniform depth distribution was chosen as a representative multi-element alloy film. The atomic fractions of the reference and the test CIGS films were certified by isotope dilution - inductively coupled plasma/mass spectrometry. A total number counting (TNC) method was used as a method to determine the signal intensities of the constituent elements, which are compared with their certified atomic fractions. The atomic fractions of the CIGS films were measured by various methods, such as Secondary Ion Mass Spectrometry (SIMS), Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS), X-Ray Fluorescence (XRF) analysis and Electron Probe Micro Analysis (EPMA) with Energy Dispersive X-ray Spectrometry (EDX). Fifteen laboratories from eight National Metrology Institutes (NMIs), one Designated Institute (DI) and six non-NMIs participated in this pilot study. Although the average atomic fractions of 18 data sets showed rather poor relative standard deviations of about 5.5 % to 6.8 %, they were greatly improved to about 1.5 % to 2.2 % by excluding 5 strongly deviating data sets from the average atomic fractions. In this pilot study, the average expanded uncertainties of SIMS, XPS, AES, XRF and EPMA were 3.84%, 3.68%, 3.81%, 2.88% and 2.90%, respectively. These values are much better than those in the key comparison K-67 for composition of a Fe-Ni alloy film. As a result, the quantification of CIGS films using the TNC method was found to be a good candidate as a subject for a CCQM key comparison. KW - CCQM KW - Pilot study KW - Surface analysis KW - Alloy films KW - CIGS PY - 2015 DO - https://doi.org/10.1088/0026-1394/52/1A/08017 SN - 0026-1394 SN - 1681-7575 VL - 52 IS - Technical Supplement SP - Article 08017 PB - Inst. of Physics Publ. CY - Bristol AN - OPUS4-35306 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bekemeier, Simon A1 - Caldeira Rêgo, C. R. A1 - Mai, H. L. A1 - Sikia, Ujjal A1 - Waseda, O. A1 - Apel, M. A1 - Arendt, F. A1 - Aschemann, A. A1 - Bayerlein, Bernd A1 - Courant, R. A1 - Dziwis, G. A1 - Fuchs, F. A1 - Giese, U. A1 - Junghanns, K. A1 - Kamal, M. A1 - Koschmieder, L. A1 - Leineweber, S. A1 - Luger, M. A1 - Lukas, M. A1 - Maas, J. A1 - Mertens, J. A1 - Mieller, Björn A1 - Overmeyer, L. A1 - Pirch, N. A1 - Reimann, J. A1 - Schröck, S. A1 - Schulze, P. A1 - Schuster, J. A1 - Seidel, A. A1 - Shchyglo, O. A1 - Sierka, M. A1 - Silze, F. A1 - Stier, S. A1 - Tegeler, M. A1 - Unger, Jörg F. A1 - Weber, M. A1 - Hickel, Tilmann A1 - Schaarschmidt, J. T1 - Advancing Digital Transformation in Material Science: The Role of Workflows Within the MaterialDigital Initiative N2 - The MaterialDigital initiative represents a major driver toward the digitalization of material science. Next to providing a prototypical infrastructure required for building a shared data space and working on semantic interoperability of data, a core focus area of the Platform MaterialDigital (PMD) is the utilization of workflows to encapsulate data processing and simulation steps in accordance with findable, accessible, interoperable, and reusable principles. In collaboration with the funded projects of the initiative, the workflow working group strives to establish shared standards, enhancing the interoperability and reusability of scientific data processing steps. Central to this effort is the Workflow Store, a pivotal tool for disseminating workflows with the community, facilitating the exchange and replication of scientific methodologies. This article discusses the inherent challenges of adapting workflow concepts, providing the perspective on developing and using workflows in the respective domain of the various funded projects. Additionally, it introduces the Workflow Store’s role within the initiative and outlines a future roadmap for the PMD workflow group, aiming to further refine and expand the role of scientific workflows as a means to advance digital transformation and foster collaborative research within material science. KW - Digitalisation KW - FAIR principles KW - MaterialDigital KW - Scientific workflows KW - Semantic interoperability PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624088 DO - https://doi.org/10.1002/adem.202402149 SN - 1527-2648 IS - 2402149 SP - 1 EP - 25 PB - Wiley-VCH GmbH AN - OPUS4-62408 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Unger, Wolfgang A1 - Pelster, A. A1 - Tyler, B.J. A1 - Kösgen, M. A1 - Kassenböhmer, R. A1 - Peterson, R.E. A1 - Stöver, M. A1 - Arlinghaus, H. F. T1 - Improved 3D-imaging of a sirolimus/probucol eluting stent coating using laser postionization secondary neutral mass spectrometry and time-of-flight secondary ion mass spectrometry N2 - Implantable drug delivery systems that provide controlled and sustained release of a therapeutic agent are used in a wide variety of applications. Drug eluting stents, which are used to treat coronary artery disease, are among the most widespread of these devices, with an estimated 3x10⁶ implants annually worldwide. Controlling the rate of drug release from these devices relies on precise control of the three dimensional (3D)-distribution of the drug, so methods for measuring this distribution are of great importance. The aims of this work were to determine how 3D-imaging of polymer-free sirolimus/probucol drug eluting stent coatings could be improved through the use of laser postionization secondary neutral mass spectrometry (Laser- SNMS) and Ar cluster sputtering with time-of-flight secondary ion mass spectrometry (ToF-SIMS) and to optimize conditions for this analysis. In this study, 3D-imaging of a sirolimus/probucol dual drug eluting stent has been investigated using Laser-SNMS and ToF-SIMS. Laser-SNMS studies of pure sirolimus and probucol were undertaken using 30 keV Bi₃⁺ primary Ions and a 157 nm excimer postionization laser. Under optimal conditions, a greater than 100-fold increase in detected ion yield was observed for Laser-SNMS when compared to ToF-SIMS, although ToF-SIMS provided equal or greater yields for higher mass characteristic ions. Although the optimal laser power density for detecting probucol (5x10⁶W/cm²) was significantly lower than the optimum for sirolimus(7x10⁷W/cm²), an intermediate laser power density of 1x10⁷W/cm² was sufficient to allow imaging of both drugs. Using individual selected ion signals, ToF-SIMS and Laser-SNMS produced similar images of the two drug species. When using, however, a multivariate approach (Maximum autocorrelation factors), Laser-SNMS provided significant improvements in image contrast and small area detection when compared to ToF-SIMS. Following optimization of the technique, 3D-images of the dual drug eluting stent coating were obtained using 10 keV Ar₂₀₀₀⁺ cluster ions for sputtering and 30 keV Bi₃⁺ cluster ions for Analysis for both ToF-SIMS and Laser-SNMS. This work demonstrates the advantages of Laser-SNMS for 3D-imaging of pharmaceutical devices, which has not been previously published. Both ToF-SIMS and Laser-SNMS revealed that the outermost surface of the drug eluting coating contained pure sirolimus to a depth of a few tens of nanometers, with a few channels of sirolimus extending to a depth of around 1 lm. Below about 1 lm, the two drugs were uniformly mixed. Using the 10 keV Ar₂₀₀₀⁺ sputter beam, the authors were able to sputter through the complete drug coating (~6 μm) without observing any accumulated damage in the organic layer. The two techniques showed complementary strengths: ToF-SIMS offers faster data collection and better detected ion yield for larger characteristic ions than Laser-SNMS, and Laser-SNMS offers significantly enhanced detected ion yield for smaller fragment ions, allowing for improved Image contrast and Resolution of smaller features. KW - Imaging ToF SIMS KW - Eluting stent PY - 2016 DO - https://doi.org/10.1116/1.4964687 SN - 1934-8630 SN - 1559-4106 VL - 11 IS - 4 SP - 041001-1 EP - 041001-10 PB - AVS: Science & Technology of Materials, Interfaces, and Processing AN - OPUS4-38272 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leach, R.K. A1 - Boyd, R. A1 - Burke, T. A1 - Danzebrink, H.-U. A1 - Dirscherl, K. A1 - Dziomba, T. A1 - Gee, M. A1 - Koenders, L. A1 - Morazzani, V. A1 - Pidduck, A. A1 - Roy, D. A1 - Unger, Wolfgang A1 - Yacoot, A. T1 - The European nanometrology landscape N2 - This review paper summarizes the European nanometrology landscape from a technical perspective. Dimensional and chemical nanometrology are discussed first as they underpin many of the developments in other areas of nanometrology. Applications for the measurement of thin film parameters are followed by two of the most widely relevant families of functional properties: measurement of mechanical and electrical properties at the nanoscale. Nanostructured materials and surfaces, which are seen as key materials areas having specific metrology challenges, are covered next. The final section describes biological nanometrology, which is perhaps the most interdisciplinary applications area, and presents unique challenges. Within each area, a review is provided of current status, the capabilities and limitations of current techniques and instruments, and future directions being driven by emerging industrial measurement requirements. Issues of traceability, standardization, national and international programmes, regulation and skills development will be discussed in a future paper. KW - Nanotechnology KW - Metrology KW - Chemistry KW - Surface analysis PY - 2011 DO - https://doi.org/10.1088/0957-4484/22/6/062001 SN - 0957-4484 SN - 1361-6528 VL - 22 IS - 6 SP - 062001-1 - 062001-15 PB - IOP Publishing Ltd. CY - Bristol AN - OPUS4-23259 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Opitz, P. A1 - Besch, L. A1 - Panthöfer, M. A1 - Kabelitz, Anke A1 - Unger, R. A1 - Emmerling, Franziska A1 - Mondeshki, M. A1 - Tremel, W. T1 - Insights into the In Vitro Formation of Apatite from Mg‐Stabilized Amorphous Calcium Carbonate N2 - A protein‐free formation of bone‐like apatite from amorphous precursors through ball‐milling is reported. Mg2+ ions are crucial to achieve full amorphization of CaCO3. Mg2+ incorporation generates defects which strongly retard a recrystallization of ball‐milled Mg‐doped amorphous calcium carbonate (BM‐aMCC), which promotes the growth of osteoblastic and endothelial cells in simulated body fluid and has no effect on endothelial cell gene expression. Ex situ snapshots of the processes revealed the reaction mechanisms. For low Mg contents (<30%) a two phase system consisting of Mg‐doped amorphous calcium carbonate (ACC) and calcite “impurities” was formed. For high (>40%) Mg2+ contents, BM‐aMCC follows a different crystallization path via magnesian calcite and monohydrocalcite to aragonite. While pure ACC crystallizes rapidly to calcite in aqueous media, Mg‐doped ACC forms in the presence of phosphate ions bone‐like hydroxycarbonate apatite (dahllite), a carbonate apatite with carbonate substitution in both type A (OH−) and type B (PO43−) sites, which grows on calcite “impurities” via heterogeneous nucleation. This process produces an endotoxin‐free material and makes BM‐aMCC an excellent “ion storage buffer” that promotes cell growth by stimulating cell viability and metabolism with promising applications in the treatment of bone defects and bone degenerative diseases. KW - Total Scattering KW - XRD KW - Mechanochemistry PY - 2020 DO - https://doi.org/10.1002/adfm.202007830 VL - 31 IS - 3 SP - 7830 PB - Wiley VHC-Verlag AN - OPUS4-51761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Anzt, H. A1 - Bach, F. A1 - Druskat, S. A1 - Löffler, F. A1 - Loewe, A. A1 - Renard, B. Y. A1 - Seemann, G. A1 - Struck, A. A1 - Achhammer, E. A1 - Aggarwal, P. A1 - Appel, F. A1 - Bader, M. A1 - Brusch, L. A1 - Busse, C. A1 - Chourdakis, G. A1 - Dabrowski, P. W. A1 - Ebert, P. A1 - Flemisch, B. A1 - Friedl, S. A1 - Fritzsch, B. A1 - Funk, M. D. A1 - Gast, V. A1 - Goth, F. A1 - Grad, J. A1 - Hegewald, J. A1 - Hermann, S. A1 - Hohmann, F. A1 - Janosch, S. A1 - Kutra, D. A1 - Linxweiler, J. A1 - Muth, Thilo A1 - Peters-Kottig, W. A1 - Rack, F. A1 - Raters, F. H. C. A1 - Rave, S. A1 - Reina, G. A1 - Reißig, M. A1 - Ropinski, T. A1 - Schaarschmidt, J. A1 - Seibold, H. A1 - Thiele, J. P. A1 - Uekermann, B. A1 - Unger, S. A1 - Weeber, R. T1 - An environment for sustainable research software in Germany and beyond: current state, open challenges, and call for action N2 - Research software has become a central asset in academic research. It optimizes existing and enables new research methods, implements and embeds research knowledge, and constitutes an essential research product in itself. Research software must be sustainable in order to understand, replicate, reproduce, and build upon existing research or conduct new research effectively. In other words, software must be available, discoverable, usable, and adaptable to new needs, both now and in the future. Research software therefore requires an environment that supports sustainability. Hence, a change is needed in the way research software development and maintenance are currently motivated, incentivized, funded, structurally and infrastructurally supported, and legally treated. Failing to do so will threaten the quality and validity of research. In this paper, we identify challenges for research software sustainability in Germany and beyond, in terms of motivation, selection, research software engineering personnel, funding, infrastructure, and legal aspects. Besides researchers, we specifically address political and academic decision-makers to increase awareness of the importance and needs of sustainable research software practices. In particular, we recommend strategies and measures to create an environment for sustainable research software, with the ultimate goal to ensure that software-driven research is valid, reproducible and sustainable, and that software is recognized as a first class citizen in research. This paper is the outcome of two workshops run in Germany in 2019, at deRSE19 - the first International Conference of Research Software Engineers in Germany - and a dedicated DFG-supported follow-up workshop in Berlin. KW - Research Software KW - Sustainable Software Development KW - Academic Software KW - Software Infrastructure KW - Software Training KW - Software Licensing PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522029 DO - https://doi.org/10.12688/f1000research.23224.2 VL - 9 SP - 1 EP - 35 AN - OPUS4-52202 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Unger, Wolfgang A1 - Schwarz, F. A1 - Heinrich, Thomas A1 - Kaufmann, J. O. A1 - Lippitz, Andreas A1 - Puttreddy, R. A1 - Rissanen, K. A1 - Schalley, C. A. T1 - Photocontrolled on-surface pseudorotaxane formation with well-ordered macrocycle multilayers N2 - The photoinduced pseudorotaxane formation between a photoresponsive axle and a tetralactam macrocycle was investigated in solution and on glass surfaces with immobilized multilayers of macrocycles. In the course of this reaction, a novel photoswitchable binding station with azobenzene as the photoswitchable unit and diketopiperazine as the binding station was synthesized and studied by NMR and UV/Vis spectroscopy. Glass surfaces have been functionalized with pyridine-terminated SAMs and subsequently withmultilayers of macrocycles through layer-by-layer self assembly. A preferred orientation of the macrocycles could be confirmed by NEXAFS spectroscopy. The photocontrolled Deposition of the axle into the surface-bound macrocycle-multilayers was monitored by UV/Vis spectroscopy and led to an increase of the molecular order, as indicated by more substantial linear dichroism effects in angle-resolved NEXAFS spectra. KW - Well-ordered macrocycle multilayers KW - XPS KW - NEXAFS PY - 2016 DO - https://doi.org/10.1002/chem.201603156 SN - 0947-6539 SN - 1521-3765 VL - 22 IS - 40 SP - 14383 EP - 14389 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-38270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, R. T1 - Experimentally calibrated modeling technique for the cross linking mechanism of epoxy resin and its influence on mechanical properties N2 - Epoxy resins are one of the first choices for structural adhesives and are widely used in combination with fibers as fiber reinforced plastics (FRP). The mechanical properties are the result of the complex chemical network structure that is generated by the thermally catalyzed cross linking reaction. Numerical simulations on the atomistic length scale are appropriate tools to understand and improve the mechanical properties and its mechanisms of epoxy resins. This leads to the necessity of a model generation procedure that covers the characteristic cross linking mechanisms of epoxy resins and is able to generate a realistic representation of the network structure. Research in the field of Molecular Dynamic based curing kinematics of polymers has led to cross linking procedures that are based on the main chemical curing reaction and can produce models, whose mechanical properties are in agreement with experimental values. Nevertheless an assessment of the realism of these cross linking procedures is difficult, since various complex aspects, such as the influence of the activator molecules or catalyzing chemical reactions may be important, but are hard to characterize. By using the method of in situ near-infrared spectroscopy (NIR) the time and temperature evolution of the reactive groups, epoxy and either amine or anhydrite curing groups, can be measured. It has been shown that this method is well suited for analyzing the curing process and to characterize the fully hardened epoxy resin. Thus NIR measurements of the cross linking kinetics of epoxy resins give a valuable insight in the curing process that can be used to calibrate and assess numerical approaches of the cross linking procedure. A modeling technique for the curing kinematics of epoxy resins is presented, that is able to realistically represent the cross linking mechanism and generate simulation models with characteristics in good agreement with experimentally analyzed cured epoxy resins. This is achieved by calibrating the cross linking parameters and is shown by a comparison of both, the cross linking procedure and the resulting network structure, with experimental results of NIR measurements. The modeling approach is incorporated in the Molecular Dynamic Finite Element Method (MDFEM) framework and implements a step by step molecular network build-up. This allows to perform MDFEM equilibrium iterations during the curing procedure in order to create realistic and well equilibrated simulation models. Furthermore MDFEM simulations of tensile tests are presented to evaluate the influence of the network structure on the elastic mechanical properties. These numerical tests also illustrate the need for accurate models when deriving material properties from atomistic length scale simulations. T2 - ICCS 20 CY - Paris, France DA - 04.09.2017 KW - Epoxy resin KW - NIR spectroscopy KW - Mechanics PY - 2017 AN - OPUS4-42416 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baer, D. R. A1 - Karakoti, A. S. A1 - Clifford, C. A. A1 - Minelli, C. A1 - Unger, Wolfgang T1 - Importance of sample preparation on reliable surface characterisation of nano‐objects: ISO standard 20579‐4 N2 - The international ISO Standard 20579‐4, dealing with the history and preparation of nano‐objects for surface analysis, has been developed to help address some of the replication and reproducibility issues caused by the fundamental nature of nanoobjects. Although all types of samples requiring surface analysis need thoughtful preparation, nano‐objects, for which many properties are controlled by their surfaces, present additional challenges in order to avoid variations and artefacts due to the handling and preparation of materials prior to analysis. This international standard is part of a series of standards related to preparation of samples for surface chemical analysis. Parts 1 and 2 of ISO Standard series 20579 address general issues that apply to many samples. Part 3, which is still in development, will focus on biomaterials. Part 4 specifically considers issues that arise due to the inherent nature of nano‐objects. Because of sensitivity to their environment, the standard indicates the minimum Information that needs to be reported about the handling and preparation of nano‐objects prior to surface analysis. This information should become part of sample provenance information that helps assure the reliability and usefulness of data obtained from surface‐analysis in the context of the synthesis, processing, and analysis history of a batch of material. Application of this standard can help address reproducibility and traceability issues associated with synthesis, processing, and characterization of nano‐objects in research and commercial applications. KW - Nano‐object characterization KW - Nanoparticle characterization KW - Provenance information KW - Sample preparation KW - Surface analysis PY - 2018 DO - https://doi.org/10.1002/sia.6490 SN - 0142-2421 SN - 1096-9918 VL - 50 IS - 9 SP - 902 EP - 906 PB - John Wiley & Sons, Ltd. AN - OPUS4-45830 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dietrich, Paul A1 - Horlacher, T. A1 - Gross, Thomas A1 - Wirth, Thomas A1 - Castelli, R. A1 - Shard, A.G. A1 - Alexander, M. A1 - Seeberger, P. H. A1 - Unger, Wolfgang T1 - Surface analytical characterization of carbohydrate microarrays N2 - Microarrays are a versatile platform for diagnostics and high-throughput analysis. Carbohydrate microarrays are valuable tools to investigate interactions with other molecules since many glycans are involved in fundamental biological processes. A combined X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) surface analysis was used to investigate the basic steps in the production of carbohydrate microarrays. The preparation included coupling of a thiol-terminated mannoside to maleimide-functionalized glass surfaces derived from γ-aminopropyl silane (GAPS) slides. XPS results clearly demonstrate successful chemical modification in each fabrication step, and ToF-SIMS imaging revealed immobilized carbohydrates in the spotted regions of the final microarray. KW - Carbohydrates KW - Microarrays KW - XPS KW - ToF-SIMS KW - Nona-mannoside KW - Maleimide surfaces KW - Surface analysis PY - 2010 DO - https://doi.org/10.1002/sia.3255 SN - 0142-2421 SN - 1096-9918 VL - 42 SP - 1188 EP - 1192 PB - Wiley CY - Chichester AN - OPUS4-21500 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gross, Thomas A1 - Pippig, F. A1 - Merz, B. A1 - Merz, R. A1 - Vohrer, U. A1 - Mix, Renate A1 - Steffen, H. A1 - Bremser, Wolfram A1 - Unger, Wolfgang T1 - Determination of OH groups at plasma oxidised poly(propylene) by TFAA chemical derivatisation XPS: an inter-laboratory comparison N2 - A first inter-laboratory comparison was conducted to demonstrate and document the capability of interested laboratories to measure the fraction of C—OH species on a plasma oxidised poly(propylene) sample by using a chemical derivatisation XPS approach. This report presents the results from that inter-laboratory comparison and includes the data received for the measured values and their associated standard deviations of laboratory means, at a 95% confidence level. The measurements were guided by a protocol developed within the group before and summarised shortly in the paper. Standard deviations that may characterise the state-of-the-art for the nominally simple and rather often practised case of TFAA chemical derivatisation XPS of C—OH species on a plasma oxidised polyolefin surface are calculated following ISO 5725-2:1994. The main conclusion is that the associated degree of equivalence reached by the participating laboratories in this comparison is still low. Further research to improve chemical derivatisation XPS protocols is mandatory. KW - Chemical derivatisation KW - ESCA/XPS KW - Inter-laboratory comparison KW - Photoelectron spectroscopy (PES) KW - Poly(propylene) (PP) PY - 2010 DO - https://doi.org/10.1002/ppap.200900142 SN - 1612-8850 SN - 1612-8869 VL - 7 IS - 6 SP - 494 EP - 503 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-21678 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -