TY - JOUR A1 - Mi, W. A1 - Josephs, R. D. A1 - Melanson, J. E. A1 - Dai, X. A1 - Wang, Y. A1 - Zhai, R. A1 - Chu, Z. A1 - Fang, X. A1 - Thibeault, M.-P. A1 - Stocks, B. B. A1 - Meija, J. A1 - Bedu, M. A1 - Martos, G. A1 - Westwood, S. A1 - Wielgosz, R. I. A1 - Liu, Q. A1 - Teo, T. L. A1 - Liu, H. A1 - Tan, Y. J. A1 - Öztuğ, M. A1 - Saban, E. A1 - Kinumi, T. A1 - Saikusa, K. A1 - Schneider, Rudolf A1 - Weller, Michael G. A1 - Konthur, Zoltán A1 - Jaeger, Carsten A1 - Quaglia, M. A1 - Mussell, C. A1 - Drinkwater, G. A1 - Giangrande, C. A1 - Vaneeckhoutte, H. A1 - Boeuf, A. A1 - Delatour, V. A1 - Lee, J. E. A1 - O'Connor, G. A1 - Ohlendorf, R. A1 - Henrion, A. A1 - Beltrão, P. J. A1 - Naressi Scapin, S. M. A1 - Sade, Y. B. T1 - PAWG Pilot Study on Quantification of SARS-CoV-2 Monoclonal Antibody - Part 1 N2 - Under the auspices of the Protein Analysis Working Group (PAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a pilot study, CCQM-P216, was coordinated by the Chinese National Institute of Metrology (NIM), National Research Council of Canada (NRC) and the Bureau International des Poids et Mesures (BIPM). Eleven Metrology Institutes or Designated Institutes and the BIPM participated in the first phase of the pilot study (Part 1). The purpose of this pilot study was to develop measurement capabilities for larger proteins using a recombinant humanized IgG monoclonal antibody against Spike glycoprotein of SARS-CoV-2 (Anti-S IgG mAb) in solution. The first phase of the study was designed to employ established methods that had been previously studies by the CCQM Protein Analysis Working Group, involving the digestion of protein down to the peptide or amino acid level. The global coronavirus pandemic has also led to increased focus on antibody quantitation methods. IgG are among the immunoglobulins produced by the immune system to provide protection against SARS-CoV-2. Anti-SARS-CoV-2 IgG can therefore be detected in samples from affected patients. Antibody tests can show whether a person has been exposed to the SARS-CoV-2, and whether or not they potentially show lasting immunity to the disease. With the constant spread of the virus and the high pressure of re-opening economies, antibody testing plays a critical role in the fight against COVID-19 by helping healthcare professionals to identify individuals who have developed an immune response, either via vaccination or exposure to the virus. Many countries have launched large-scale antibody testing for COVID-19. The development of measurement standards for the antibody detection of SARS-CoV-2 is critically important to deal with the challenges of the COVID-19 pandemic. In this study, the SARS-CoV-2 monoclonal antibody is being used as a model system to build capacity in methods that can be used in antibody quantification. Amino acid reference values with corresponding expanded uncertainty of 36.10 ± 1.55 mg/kg, 38.75 ± 1.45 mg/kg, 18.46 ± 0.78 mg/kg, 16.20 ± 0.67 mg/kg and 30.61 ± 1.30 mg/kg have been established for leucine, valine, phenylalanine, isoleucine and proline, respectively. Agreement between nearly all laboratories was achieved for the amino acid analysis within 2 to 2.5 %, with one participant achieving markedly higher results due to a technical issue found in their procedure; this result was thus excluded from the reference value calculations. The relatively good agreement within a laboratory between different amino acids was not dissimilar to previous results for peptides or small proteins, indicating that factors such as hydrolysis conditions and calibration procedures could be the largest sources of variability. Peptide reference values with corresponding expanded uncertainty of 4.99 ± 0.28 mg/kg and 6.83 ± 0.65 mg/kg have been established for ALPAPIEK and GPSVFPLAPSSK, respectively. Not surprisingly due to prior knowledge from previous studies on peptide quantitation, agreement between laboratories for the peptide-based analysis was slightly poorer at 3 to 5 %, with one laboratory's result excluded for the peptide GPSVFPLAPSSK. Again, this level of agreement was not significantly poorer than that achieved in previous studies with smaller or less complex proteins. To reach the main text of this paper, click on Final Report. KW - Antibody quantification KW - Amino acid analysis KW - Peptide analysis KW - Round robin test PY - 2021 U6 - https://doi.org/10.1088/0026-1394/59/1a/08001 VL - 59 IS - 1A SP - 08001 AN - OPUS4-54972 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Taylor, G.R. A1 - Tan, R. A1 - O´Brien, A.S. A1 - Baeßler, Matthias A1 - Cuéllar, Pablo A1 - Lane, J.S. A1 - Evans, E. T1 - The use of physical model testing in the development of models for potential impact assessment on the UK rail network N2 - Most railway embankments in the UK were built in the Victorian era and are of end-tipped construction using materials (usually cohesive) excavated from adjacent cuttings, resulting in a clod-and-matrix structure. Historically, there has been a lack in understanding of the mechanical behaviour of such railway embankments. In the next decade railway traffic in the UK, particularly freight, is forecast to grow considerably. Consequently, there is a need to improve the understanding of how increases in rail traffic loading may influence the mechanical behaviour of railway embankments and thus track performance. The Rail Safety and Standards Board in conjunction with Network Rail is currently undertaking a programme of applied research into this topic. As part of these studies a programme of physical model tests has been carried out. Physical model tests can provide high quality data on system performance under a large range of loading conditions and geometrical configurations. The data can be generated rapidly, with test periods of weeks or months rather than years or decades. Additionally, boundary conditions are well-defined and controlled, compared with the complex situations encountered in full scale embankments in the field. This paper summarises the physical model test programme, the development of the test set-up, the tests themselves and the conclusions drawn. T2 - European Conference on Soil Mechanics and Geotechnical Engineering CY - Edinburgh, Scotland, UK DA - 13.09.2015 KW - Railway embankment KW - Clay fill KW - Physical model testing PY - 2015 SN - 978-0-7277-6067-8 U6 - https://doi.org/10.1680/ecsmge.60678 SP - 361 EP - 366 AN - OPUS4-39374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wachtendorf, Volker A1 - Schartel, Bernhard A1 - Lin, Xuebao A1 - Tan, Yi A1 - Schoch, R. A1 - Lang, M. A1 - Tröppner, O. A1 - Bosse, M. ED - Ziegahn, K.-F. T1 - Untersuchung der Witterungsbeständigkeit komplexer Funktionalitäten von Polymerwerkstoffen durch künstliche Bewitterung: Flammschutz N2 - In den letzten Jahrzehnten wurde die Degradation der polymeren Matrix von flammgeschützten Polymeren eingehend untersucht. Erst in den letzten Jahren jedoch hat sich die Frage der Lebensdauer der Funktionalität des Flammschutzes selbst als wichtige Fragestellung herauskristallisiert, z.B. bei Kabeln. Deshalb sollte diese Fragestellung durch systematisch-variierte künstliche Klima- und Bewitterungstests an flammgeschützten Polymerwerkstoffen untersucht werden. T2 - 50. Jahrestagung der Gesellschaft für Umweltsimulation (GUS) CY - Online meeting DA - 23.03.2022 KW - Flammschutz, Witterungsbeständigkeit, Langzeitbeständigkeit, UV, E&E PY - 2022 SN - 978-3-9818507-7-2 VL - 50 SP - 143 EP - 148 CY - Pfinztal (Berghausen) AN - OPUS4-54543 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ziesche, R.F. A1 - Hack, J. A1 - Rasha, L. A1 - Maier, M. A1 - Tan, C. A1 - Heenan, T.M.M. A1 - Markötter, Henning A1 - Kardjilov, N. A1 - Manke, I. A1 - Kockelmann, W. A1 - Brett, D.J.L. A1 - Shearing, P.R. T1 - High-speed 4D neutron computed tomography for quantifying water dynamics in polymer electrolyte fuel cells N2 - In recent years, low-temperature polymer electrolyte fuel cells have become an increasingly important pillar in a zero-carbon strategy for curbing climate change, with their potential to power multiscale stationary and mobile applications. The performance improvement is a particular focus of research and engineering roadmaps, with water management being one of the major areas of interest for development. Appropriate characterisation tools for mapping the evolution, motion and removal of water are of high importance to tackle shortcomings. This article demonstrates the development of a 4D high-speed neutron imaging technique, which enables a quantitative analysis of the local water evolution. 4D visualisation allows the time-resolved studies of droplet formation in the flow fields and water quantification in various cell parts. Performance parameters for water management are identified that offer a method of cell classification, which will, in turn, support computer modelling and the engineering of next-generation flow field designs. KW - Neutron imaging KW - Tomography KW - Polymer electrolyte membrane fuel cell PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-545978 VL - 13 IS - 1 SP - 1616 PB - Nature Publishing Group UK CY - London AN - OPUS4-54597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - BOOK A1 - Schoch, R. A1 - Schartel, Bernhard A1 - Wachtendorf, Volker A1 - Tan, Yi A1 - Lin, Xuebao A1 - Tröppner, O. A1 - Lang, M. A1 - Hochrein, T. A1 - Bastian, M. T1 - Langzeit- und Witterungsstabilität von halogenfreiem Flammschutz in Polymeren N2 - Die Forderung, dass der Flammschutz von Kunststoffen nicht nur zum bei der Herstellung der jeweiligen Produkte, sondern auch über die gesamte Einsatzdauer im geforderten Maß wirksam ist, stellt eine große Aufgabe dar. Ferner ist die Anforderung für viele Produkte in der Praxis neu, da bisher vor allem der Einfluss der Flammschutzmittel auf die Stabilität der Polymerwerkstoffe, nicht aber die Stabilität des Flammschutzes untersucht wurde. Das Langzeitverhalten halogenfreier Systeme ist bis heute wenig untersucht, insbesondere weil Phosphor- und Stickstoff-basierte Systeme die oxidative Beständigkeit von Polymeren weniger zu beeinflussen scheinen als halogenhaltige FSM. Die Frage, wie zuverlässig der Flammschutz wirkt, wenn Kunststoffe einige Jahre im Innen- und Außenbereich im Einsatz sind und dabei wechselnden Beanspruchungen ausgesetzt waren, wurde bislang nur vereinzelt untersucht. Mögliche Auswirkungen von Witterungseinflüssen auf flammgeschützte Polymerwerkstoffe sind, dass die Flammschutzmittel selbst abbauen, ausgewaschen werden, oder auch durch Wechselwirkung mit den eingesetzten Additiven oder mit den Alterungsprodukten der Polymermatrix in ihrer Wirkung nachlassen. Hier bestand großer Forschungsbedarf, um an den Punkt zu gelangen, die Beständigkeit der Flammschutzeigenschaften eines Produktes über seine gesamte Lebensdauer zuverlässig garantieren zu können. Diese Fragestellung greift das durchgeführte Forschungsvorhaben auf. Ziel war die Untersuchung der Langzeitstabilität der Flammschutzwirkung von halogenfrei flammgeschützten Polymerwerkstoffen unter diversen Witterungseinflüssen. Dazu wurden die Schädigungsmechanismen der Polymerwerkstoffe und der Flammschutzmittel sowie die auftretenden Wechselwirkungen analysiert, um ein Verständnis für die ablaufenden Prozesse zu entwickeln und Empfehlung für die Reduzierung der Alterung zu erarbeiten. Gegenstand der Untersuchungen waren anwendungsrelevante Flammschutz-Konzepte, die miteinander verglichen wurden. Die Erarbeitung von Struktur-Eigenschafts-Beziehungen ermöglichte die Beschreibung der Empfindlichkeiten und den Vergleich zwischen den Systemen. Darauf basierend wurden für die FSM spezifische Leitlinien für die Optimierung der Langzeitstabilität des Flammschutzes erstellt. N2 - The requirement that the flame retardancy of plastics is still effective to the required degree not only at the time of manufacture of the respective products, but also over the entire period of use, is a major challenge in view of the very long periods of time involved. In addition, the requirement is new for many products in practice, as up to now the influence of flame retardants on the stability of the polymer materials has been investigated, but not the stability of the flame retardant itself. The long-term behaviour of halogen-free systems has been little studied to date, especially because phosphorus- and nitrogen-based systems seem to have a much smaller influence on the oxidative stability of polymers than halogene containing flame retardants. The question of how reliable flame retardancy is when plastic products have been in use for several years indoors and outdoors and have been exposed to a wide range of climatic stresses has only been investigated in isolated cases. Possible effects of weathering on flame-retarded polymer materials are that the flame retardants themselves degrade, migrate or are washed out, or that their effect diminishes through interaction with other additives used or with the ageing products of the polymer matrix. At this point, there was a great need for research in order to reach the point where the stability of the flame retardant properties of a product can be reliably guaranteed over its entire service life. This question is taken up by the research project carried out. The aim of the research project was the systematic investigation of the long-term stability of the flame-retardant effect of halogen-free flame-retardant polymer materials under various weather conditions. For this purpose, the predominant damage mechanisms of the polymers and the flame retardants as well as the interactions occurring were analysed in order to develop an understanding of the processes taking place and to work out recommendations for reducing ageing. Subject of the investigations were different applicationrelevant flame retardant concepts, which were compared with each other. The development of structure-property relationships enabled the description of the specific sensitivities and the comparison between the different systems. Based on this, specific guidelines for the optimisation of the long-term stability of the flame retardants were developed for the different flame retardants. KW - Durability KW - Flame retardant KW - Flammschutz KW - Weathering KW - Ethylene-vinyl acetate KW - Cables KW - Polyamid KW - Langzeitstabilität PY - 2021 SN - 978-3-8440-7781-0 SN - 2364-754X SP - 1 EP - 222 PB - Shaker CY - Düren AN - OPUS4-54274 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tan, K. H. A1 - Sattari, S. A1 - Donskyi, Ievgen A1 - Cuellar-Camacho, J. L. A1 - Cheng, C. A1 - Schwibbert, Karin A1 - Lippitz, Andreas A1 - Unger, Wolfgang A1 - Gorbushina, Anna A1 - Adeli, M. A1 - Haag, R. T1 - Functionalized 2D nanomaterials with switchable binding to investigate graphene–bacteria interactions N2 - Graphene and its derivatives have recently attracted much attention for sensing and deactivating pathogens. However, the mechanism of multivalent interactions at the graphene–pathogen interface is not fully understood. Since different physicochemical parameters of graphene play a role at this interface, control over graphene’s structure is necessary to study the mechanism of these interactions. In this work, different graphene derivatives and also zwitterionic graphene nanomaterials (ZGNMs) were synthesized with defined exposure, in terms of polymer coverage and functionality, and isoelectric points. Then, the switchable interactions of these nanomaterials with E. coli and Bacillus cereus were investigated to study the validity of the generally proposed “trapping” and “nano-knives” mechanisms for inactivating bacteria by graphene derivatives. It was found that the antibacterial activity of graphene derivatives strongly depends on the accessible area, i.e. edges and basal plane of sheets and tightness of their agglomerations. Our data clearly confirm the authenticity of “trapping” and “nano-knives” mechanisms for the antibacterial activity of graphene sheets. KW - XPS KW - Graphene KW - Graphene–bacteria interaction PY - 2018 U6 - https://doi.org/10.1039/c8nr01347k SN - 2040-3364 SN - 2040-3372 VL - 10 IS - 20 SP - 9525 EP - 9537 PB - RSC CY - London AN - OPUS4-45084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tan, K. H. A1 - Sattari, S. A1 - Beyranvand, S. A1 - Faghani, A. A1 - Ludwig, K. A1 - Schwibbert, Karin A1 - Böttcher, C. A1 - Haag, R. A1 - Adeli, M. T1 - Thermoresponsive Amphiphilic Functionalization of Thermally Reduced Graphene Oxide to Study Graphene/Bacteria Hydrophobic Interactions N2 - An understanding of the interactions of 2D nanomaterials with pathogens is of vital importance to developing and controlling their antimicrobial properties. In this work, the interaction of functionalized graphene with tunable hydrophobicity and bacteria is investigated. Poly-(ethylene glycol)-block-(poly-N-isopropylacrylamide) copolymer (PEG-b-PNIPAM) with the triazine joint point was attached to the graphene Surface by a nitrene [2 + 1] cycloaddition reaction. By thermally switching between hydrophobic and hydrophilic states, functionalized graphene sheets were able to bind to bacteria. Bacteria were eventually disrupted when the functionality was switched to the hydrophobic state. On the basis of measuring the different microscopy methods and a live/dead viability assay, it was found that Escherichia coli (E. coli) bacteria are more susceptible to hydrophobic interactions than B. cereus bacteria, under the same conditions. Our investigations confirm that hydrophobic interaction is one of the main driving forces at the presented graphene/bacteria interfaces and promotes the antibacterial activity of graphene derivatives significantly. KW - 2D nanomaterials KW - Functionalized graphene KW - Antimicrobial KW - Hydrophobic interaction PY - 2019 U6 - https://doi.org/10.1021/acs.langmuir.8b03660 VL - 35 IS - 13 SP - 4736 EP - 4746 PB - ACS Publications AN - OPUS4-49235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -