TY - CONF A1 - Hutchinson, R. A1 - Wilkins, J. A1 - Summerfield, L. A1 - O’Connor, C. A1 - McLachlin, K. A1 - Jakubowski, Norbert A1 - Traub, Heike A1 - Esteban-Fernández, Diego T1 - Performance and data from an elemental microscope - The NWR image N2 - The NWRimage system is the first elemental imaging-specific laser ablation instrument, offering breakthrough sub-micron spatial resolution and ultra-fast signal response for high throughput rates. Laser ablation (LA) systems are used in conjunction with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) systems to detect and analyze tiny amounts of material. As ICP-MS systems have become more sensitive, a need has emerged for LA imaging tools with < 1 micron spatial resolution - a capability not previously available on the market. The NWRimage is provided with a carefully designed aerosol path from point of ablation to injection into the ICP itself. This aerosol path combined with a novel Dual Concentric Injector (DCI) ICP torch, yields < 50ms signal response to accelerate the speed of analysis and enabling enhanced sample throughput. The LA system is used for bio imaging of single cells and medical tissue samples. T2 - Winter Conference on Plasma Spectrochemistry 2016 CY - Tucson, Arizona, USA DA - 11.01.2016 KW - Laser ablation KW - Bio imaging PY - 2016 AN - OPUS4-36513 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Geißler, Daniel A1 - Hildebrandt, N. T1 - Recent developments in Förster resonance energy transfer (FRET) diagnostics using quantum dots N2 - The exceptional photophysical properties and the nanometric dimensions of colloidal semiconductor quantum dots (QD) have strongly attracted the bioanalytical community over the last approximately 20 y. In particular, the integration of QDs in the analysis of biological components and interactions, and the related diagnostics using Förster resonance energy transfer (FRET), have allowed researchers to significantly improve and diversify fluorescence-based biosensing. In this TRENDS article, we review some recent developments in QD-FRET biosensing that have implemented this technology in electronic consumer products, multiplexed analysis, and detection without light excitation for diagnostic applications. In selected examples of smartphone-based imaging, single- and multistep FRET, steady-state and time-resolved spectroscopy, and bio/chemiluminescence detection of QDs used as both FRET donors and acceptors, we highlight the advantages of QD-based FRET biosensing for multiplexed and sensitive diagnostics. KW - Fluorescence spectroscopy and imaging KW - Multiplexing immunoassay KW - Nanoparticle KW - DNA/RNA KW - BRET/CRET PY - 2016 DO - https://doi.org/10.1007/s00216-016-9434-y SN - 1618-2642 SN - 1618-2650 VL - 408 IS - 17 SP - 4475 EP - 4483 PB - Springer-Verlag CY - Berlin, Heidelberg AN - OPUS4-36546 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Traub, Heike A1 - Drescher, Daniela A1 - Büchner, T. A1 - Zeise, Ingrid A1 - Kneipp, Janina A1 - Jakubowski, Norbert T1 - Studying cellular uptake and processing of nanoparticles by LA-ICP-MS N2 - In recent years, elemental imaging of biological samples using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is gaining in importance. Latest improvements regarding spatial resolution (down to 1 µm) and washout time make LA-ICP-MS particularly interesting for single cell analysis. Many current nanomaterials can serve as contrast agents in cellular or tissue imaging, drug delivery vehicles or therapeutics, whereas others can cause toxic effects. In order to evaluate nano-bio interactions, the number of nanoparticles (NPs) inside cells as well as their localisation within cellular substructures is of particular interest. LA-ICP-MS was used to study the NP pathway from uptake, via intracellular processing up to cell division. Fibroblast cells were incubated with different metallic NPs under varying experimental conditions. For LA analysis the cells were fixed with formaldehyde and dried. Our results show that LA-ICP-MS is able to localise NP aggregates within cellular substructures. The NPs accumulate in the perinuclear region in the course of intracellular processing, e.g. multivesicular fusion and endosomal maturation, but do not enter the nucleus [1, 2]. A strong dependence of NP uptake on concentration and incubation time was found. Additionally, the number of NPs internalized by individual cells was determined and variations within the cell population became visible. A new laser ablation system providing a short washout time (50 ms) together with small spot sizes (< 4 µm) and high repetition rates allows high spatial resolution applications. First results of cell imaging will be shown. The findings demonstrate the potential of LA-ICP-MS enabling insight into NP uptake and intracellular distribution dependent on experimental parameters. T2 - 8th Nordic Conference on Plasma Spectrochemistry CY - Loen, Norway DA - 05.06.2016 KW - Imaging KW - LA-ICP-MS KW - Cell KW - Nanoparticles PY - 2016 AN - OPUS4-36500 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gottlieb, Cassian A1 - Grothe, Sven A1 - Wilsch, Gerd T1 - Cluster algorithm for the evaluation of heterogeneous materials by LIBS N2 - The laser-induced breakdown spectroscopy (LIBS) is a fast method to provide multi-elemental analysis of any sample. At the Federal Institute for Materials Research and Testing (BAM) the LIBS technique is applied on building materials to measure ingress profiles of harmful species like chloride and alkalis. The ingress depth and the quantitative amount is important for the evaluation of the potential for damage processes like the alkali-silica reaction or chloride-induced corrosion. Concrete as an example is a highly heterogeneous material with 1/7 cement (major component CaO) and 6/7 aggregates (SiO2) with different grain sizes. Due to a scanning procedure a two dimensional element distribution of a concrete surface can be measured. In order to have an automated Separation method to evaluate heterogeneous materials, different cluster algorithm have been tested. Best results have been achieved with the Expectation-Maximization-Algorithm (EM-Algorithm). T2 - Chemometrics in analytical chemistry CY - Barcelona, Spain DA - 06.06.2016 KW - LIBS KW - Concrete KW - Multivariate analysis PY - 2016 AN - OPUS4-36471 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Asadujjaman, Asad A1 - Bertin, Annabelle T1 - Aggregation behavior of UCST-Type Poly(Acrylamide-co-Acrylonitrile) copolymer N2 - Thermoresponsive polymers have shown great potential in applications such as bioseparation, drug delivery and diagnostic. Only few thermoresponsive polymers that present an upper critical solution temperature (UCST) in a relevant temperature range, i.e. phase separate from solution upon cooling, have been reported so far. Moreover, the most studied UCST type polymers namely polybetaines are difficult to use under physiological conditions, which significantly restricts their potential applications. Therefore, UCST polymers with sharp and robust phase transition in physiological conditions (in the presence of salts, ions etc.) are highly needed in order to extend the range of applications of this class of polymers. Herein, a robust UCST-type copolymer of acrylamide (AAm) and acrylonitrile (AN) (poly(AAm-co-AN)) was prepared by reversible addition fragmentation chain transfer (RAFT) polymerization and its thermo-induced aggregation behavior in aqueous media was studied. At temperature below the UCST, the copolymer chains were aggregated together. The aggregate size was found to be larger with increasing AN contents and became smaller upon dilution of the copolymer solutions. While above the UCST, the copolymer chains were expanded and weekly associated in solution. The association between the copolymer chains formed smaller aggregates with increasing the AN contents or the dilution of the solutions. A model is proposed to explain such aggregation-association behavior of the Fig. 1. Figure 1. Schematic illustration of the proposed thermos-induced aggregation behavior of the poly(AAm-co-AN) in aqueous solution. T2 - World Congress on Living Polymerizations and Polymers 2016 CY - Budapest, Hungry DA - 29.05.2016 - 03.06.2016 KW - Polymer KW - UCST PY - 2016 AN - OPUS4-36491 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jakubowski, Norbert T1 - ICP-MS with Sector Field Devices N2 - This lecture is an introduction to ICP-MS with a double focusing magnetic sector mass analyzer. It offers fundamental background, a thorough discussion of analytical features, and state of the art information on applications. Different types of double focusing instruments also are considered. Specific topics include fundamental aspects of ICP-MS (physical properties of a double focusing instrument, operational characteristics in comparison with quadrupole instruments); analytical characteristics (spectral and non-spectral interferences, figures of merit in low and high resolution modes, blanks and memory effects, HPLC and GC interfaces), and applications (industrial including ultra-pure reagents and alloys, environmental, geological, and biomedical materials). T2 - Winter Conference on Plasma Spectrochemistry CY - Tucson, Arizona, USA DA - 10.01.2016 KW - High-resolution ICP-MS KW - Figures of merit KW - Interfaces KW - Applications KW - Ultra-trace analysis PY - 2016 AN - OPUS4-37148 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grauel, Bettina T1 - Nd-sensitized tri-doped UCNP systems N2 - This presentation gives a short overview of the PhD student's research topics and interests, within the scope of the 2016 UPCON Spring School. T2 - UPCON 2016 Spring School CY - Breslau, Poland DA - 25.05.2016 KW - UCNP KW - Nd-sensitizer PY - 2016 AN - OPUS4-37223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grauel, Bettina A1 - Würth, Christian A1 - Wiesholler, L. M. A1 - Hirsch, T. A1 - Resch-Genger, Ute T1 - Nd as sensitizer in NaYF4:Yb,Er,Nd tri-doped upconversion nanocrystals N2 - In recent years, upconversion nanocrystals (UCNC) have shown great promise for biological and medical applications, mainly because of their excitation in the NIR region, which provides minimum fluorescence background and a rather deep penetration into biological samples, as opposed to excitation in the visible or UV region. Moreover, they show a multitude of characteristic narrow emission bands as basis for ratiometric measurements. Commonly, Yb is the sensitizer of choice, because of a comparatively high absorption cross section, simple energy scheme, and rather efficient energy transfer to the activator, mostly Er, Tm or Ho. A main disadvantage of the use of Yb as sensitizer for biological and medical applications is its absorption band at 976 nm and hence the use of an excitation wavelength at which water has a non-negligible absorption. This can lead to significant sample heating, especially at long illumination times or high excitation power densities, and thus, tissue damage or even cell death. A possible solution is the tri-doping of UCNC with Nd as sensitizer, which can be excited efficiently at around 800 nm, where water absorption is at minimum. The use of Nd as a sensitizer and Yb as a bridge between Nd and the activator Er in NaYF₄ nanocrystals is a relatively new way to overcome the problems of heating of samples in an aqueous environment. Disadvantages can arise from the tri-doping, which can favor non-radiative relaxation due to the more complicated excitation process compared to e.g., simple Yb,Er-doped UCNC, which might lower the upconversion quantum yields in these tri-doped systems. In order to quantify clear advantages, NaYF₄:Yb,Er,Nd nanoparticles were synthesized and spectroscopically studied using an 8 W 804 nm laser diode and a custom-designed Edinburgh instruments FSP980 spectrometer. Wavelength-dependent studies of the emission intensities and the decay kinetics of these tri-doped UCNC at different excitation power densities and excitation pulse widths revealed the clear advantages of preventing water absorption on measurable luminescence signals. We were able to show the influence of pulse width and excitation power density on the luminescence intensities and decay kinetics lifetimes at different emission wavelengths. Additionally, we can clearly discern power density-dependent and independent peaks in the emission spectra. In summary, we demonstrate that the tri-doping of NaYF₄:Yb,Er,Nd nanoparticles is a very promising approach to render UCNC more efficient and to make them better suitable for biological and medical applications requiring measurements in aqueous environment. T2 - UPCON 2016 Conference CY - Breslau, Poland DA - 23.05.2016 KW - UCNP KW - Nd-sensitizer KW - excitation power density PY - 2016 AN - OPUS4-37224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Frenzel, Florian T1 - Spectroscopic study of plasmon enhanced upconversion nanoparticles N2 - The presentation gave an overview of the topic, the aims and the task allocation of the M-ERA.NET founded project named “Nanohype”. In this project four research teams working hand in hand on computational modeling, synthesis and experimental validation to design novel metal-shelled Upconversion-NP combining plasmonic interactions. As Ph.D. student at the BAM I am responsible for the optical characterization (measurements of lifetimes, Quantum Yields and PL emissions ) of these promising novel systems. T2 - SpringSchool, UpCon2016 CY - Wrocław (Breslau), Polen DA - 25.05.2016 KW - Field Enhancement KW - Upconversion KW - Core-Shell KW - FRET KW - Plasmonic PY - 2016 AN - OPUS4-37225 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Büchner, T. A1 - Drescher, D. A1 - Merk, V. A1 - Traub, Heike A1 - Guttmann, P. A1 - Werner, St. A1 - Jakubowski, Norbert A1 - Schneider, G. A1 - Kneipp, J. T1 - Biomolecular environment, quantification, and intracellular interaction of multifunctional magnetic SERS nanoprobes N2 - Multifunctional composite nanoprobes consisting of iron oxide nanoparticles linked to silver and gold nanoparticles, Ag–Magnetite and Au–Magnetite, respectively, were introduced by endocytic uptake into cultured fibroblast cells. The cells containing the non-toxic nanoprobes were shown to be displaceable in an external magnetic field and can be manipulated in microfluidic channels. The distribution of the composite nanostructures that are contained in the endosomal system is discussed on the basis of surfaceenhanced Raman scattering (SERS) mapping, quantitative laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) micromapping, and cryo soft X-ray tomography (cryo soft-XRT). Cryo soft-XRT of intact, vitrified cells reveals that the composite nanoprobes form intra-endosomal aggregates. The nanoprobes provide SERS signals from the biomolecular composition of their surface in the endosomal environment. The SERS data indicate the high stability of the nanoprobes and of their plasmonic properties in the harsh environment of endosomes and lysosomes. The spectra point at the molecular composition at the surface of the Ag–Magnetite and Au–Magnetite nanostructures that is very similar to that of other Composite structures, but different from the composition of pure silver and gold SERS nanoprobes used for intracellular investigations. As shown by the LA-ICP-MS data, the uptake efficiency of the magnetite composites is approximately two to three times higher than that of the pure gold and silver nanoparticles. KW - Nanoparticles KW - SERS KW - Cell KW - LA-ICP-MS KW - X-ray tomography PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-371811 DO - https://doi.org/10.1039/c6an00890a SN - 0003-2654 VL - 141 IS - 17 SP - 5096 EP - 5106 PB - Royal Society of Chemistry CY - Cambridge, UK AN - OPUS4-37181 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kage, Daniel A1 - Hoffmann, Katrin A1 - Göhde, W. A1 - Thiele, T. A1 - Schedler, U. A1 - Resch-Genger, Ute T1 - Lifetime-encoded microparticles - application to flow cytometry N2 - Analytical methods require efficient and versatile strategies to measure an increasing number of analytes that can be used in conjunction with established platforms like flow cytometry. Spectral multiplexing suffers from problems such as spectral crosstalk and often requires different excitation light sources increasing instrumentation costs. Thus, the number of distinguishable reporters with intensity-based barcodes is limited. An alternative can be lifetime encoding for discrimination of fluorophores based on their fluorescence decay kinetics. We report on the suitability of µm-sized polymer particles stained with organic dyes for lifetime encoding. These dyes are excitable at a standard laser diode wavelength and detectable within a single spectral window. For lifetime-based discrimination, these dyes display sufficiently different luminescence decay kinetics. We present the spectroscopic properties of these beads and address challenges like the limited number of detectable photons in a flow for the reliable discrimination. These studies are expected to pave the road to new applications of fluorescence lifetime multiplexing for time-domain flow cytometry. T2 - DPG Spring Meeting 2016 CY - Regensburg, Germany DA - 06.03.2016 KW - flow cytometry KW - lifetime encoding KW - life sciences KW - fluorescence KW - polymer particles PY - 2016 AN - OPUS4-37153 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kage, Daniel A1 - Hoffmann, Katrin A1 - Wittkamp, M. A1 - Ameskamp, J. A1 - Göhde, W. A1 - Thiele, T. A1 - Schedler, U. A1 - Resch-Genger, Ute T1 - Lifetime-encoded microparticles for application in flow cytometry N2 - The steadily increasing number of analytes, especially in bioanalytics and environmental contexts, requires the development of efficient and versatile methods for the simultaneous determination of different parameters within a single run. Additionally, these methods should be applicable in conjunction with established platform technologies like flow cytometry. Fluorescence techniques have proven to fulfill these requirements. Commonly performed spectral multiplexing utilizing a color code suffers from several problems, such as the sensitivity of fluorescence intensity measurements to fluctuations in excitation light intensity and dye concentration and hence, photobleaching and spectral crosstalk limiting the achievable number of detection channels. Moreover, it typically requires different costly excitation light sources. T2 - Innovation Forum Senftenberg 2016 CY - Senftenberg, Germany DA - 01.06.2016 KW - flow cytometry KW - lifetime encoding KW - life sciences KW - fluorescence KW - polymer particles PY - 2016 AN - OPUS4-37154 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hsiao, I.-L. A1 - Bierkandt, Frank A1 - Reichardt, Ph. A1 - Luch, A. A1 - Huang, Y.-J. A1 - Jakubowski, Norbert A1 - Tentschert, J. A1 - Haase, A. T1 - Quantification and visualization of cellular uptake of TiO2 and Ag nanoparticles: comparison of different ICP-MS techniques N2 - Safety assessment of nanoparticles (NPs) requires techniques that are suitable to quantify tissue and cellular uptake of NPs. The most commonly applied techniques for this purpose are based on inductively coupled plasma mass spectrometry (ICP-MS). Here we apply and compare three different ICP-MS methods to investigate the cellular uptake of TiO2 (diameter 7 or 20 nm, respectively) and Ag (diameter 50 or 75 nm, respectively) NPs into differentiated mouse neuroblastoma cells (Neuro-2a cells). Cells were incubated with different amounts of the NPs. Thereafter they were either directly analyzed by laser ablation ICP-MS (LA-ICP-MS) or were lysed and lysates were analyzed by ICP-MS and by single particle ICP-MS (SP-ICP-MS). KW - Nanoparticles KW - Single particle ICP-MS KW - Laser ablation ICP-MS KW - Cellular internalization KW - Neurons PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-371620 DO - https://doi.org/10.1186/s12951-016-0203-z SN - 1477-3155 VL - 14 SP - Article 50 AN - OPUS4-37162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mielke, Johannes A1 - Martınez-Blanco, J. A1 - Peters, M. V. A1 - Hecht, S. A1 - Grill, L. T1 - Observing single-atom diffusion at a molecule-metal interface N2 - The dynamics at the interface between a close-packed porphyrin monolayer and Au(111) is investigated by time-dependent scanning tunneling microscopy, detecting the motion of single-interface adatoms in real space. Imaging sequences reveal predominant switching of the molecular appearance in adjacent molecules, pointing to a spatial correlation that is consistent with adatom diffusion from one molecule to the next. In some cases, the number of switching molecules is drastically increased, indicating collective switching events. In addition to the thermally induced motion of adatoms at the interface, also voltage pulses from the microscope tip can induce the process—revealing different yields in agreement with the model of adatom hopping. KW - STM KW - molecular switch KW - single molecule KW - switching dynamics KW - porphyrin KW - Au(111) PY - 2016 UR - http://journals.aps.org/prb/abstract/10.1103/PhysRevB.94.035416 DO - https://doi.org/10.1103/PhysRevB.94.035416 VL - 94 IS - 3 SP - 035416-1 EP - 035416-7 PB - American Physical Society AN - OPUS4-37177 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bartholmai, Matthias A1 - Johann, Sergej A1 - Kammermeier, Michael A1 - Müller, Maximilian A1 - Strangfeld, Christoph T1 - RFID sensor systems embedded in concrete – systematical investigation of the transmission characteristics N2 - Long-term completely embedded sensor systems offer innovative possibilities for structural health monitoring of concrete structures. Measuring of relevant parameters, e.g., temperature, humidity, or indication of corrosion can be performed with low energy sensors. This allows to implement passive RFID sensor systems without cable connection and battery, which are power supplied exclusively by the electromagnetic field from the external reader device. To evaluate characteristics and conditions of this concept, a systematical investigation of the transmission characteristics with variation of relevant parameters, as communication frequency, installation depth, type of concrete, moisture content, etc. is currently carried out in an interdisciplinary research project at BAM. First results are presented in this paper. T2 - 8th European Workshop On Structural Health Monitoring CY - Bilbao, Spain DA - 05.07.2016 KW - Structural health monitoring KW - Embedded sensor KW - Energy harvesting KW - Wireless sensors KW - RFID sensors KW - Transmission characteristics PY - 2016 SP - 1 EP - 5 AN - OPUS4-37129 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bartholmai, Matthias A1 - Strangfeld, Christoph A1 - Johann, Sergej A1 - Kammermeier, Michael A1 - Müller, Maximilian T1 - RFID sensor systems embedded in concrete – systematical investigation of the transmission characteristics N2 - Long-term completely embedded sensor systems offer innovative possibilities for structural health Monitoring of concrete structures. Measuring of relevant parameters, e.g., temperature, humidity, or indication of corrosion can be performed with low energy sensors. This allows to implement passive RFID sensor systems without cable connection and battery, which are power supplied exclusively by the electromagnetic field from the external Reader device. To evaluate characteristics and conditions of this concept, a systematical Investigation of the transmission characteristics with variation of relevant parameters, as communication frequency, installation depth, type of concrete, moisture content, etc. is currently carried out in an interdisciplinary research project at BAM. First results are presented in this paper. T2 - 8th European Workshop On Structural Health Monitoring CY - Bilbao, Spain DA - 05.07.2016 KW - Embedded sensor KW - Energy harvesting KW - Wireless sensors KW - RFID sensors KW - Transmission characteristics KW - Structural health monitoring PY - 2016 AN - OPUS4-37130 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Köppe, Enrico A1 - Bartholmai, Matthias A1 - Daum, Werner A1 - Gong, Xing A1 - Hofmann, Detlef A1 - Basedau, Frank A1 - Schukar, Vivien A1 - Westphal, Anja A1 - Sahre, Mario A1 - Beck, Uwe T1 - New self - diagnostic fiber optical sensor technique for structural health monitoring N2 - Fiber optic sensors have gained increasing importance in recent years and are well established in many areas of industrial applications. In this paper, we introduce a concept of a self-diagnostic fiber optic sensor. The presented sensor is to resolve the problems of embedded fiber optic sensors in complex structures and to enable the validation under operational conditions. For this purpose, different magnetostrictive coated fiber optic sensors were developed and various experiments were performed to verify their mode of Operation and to determine the respective reproducibility. The measuring principle is illustrated by obtained experimental results, which showed a change in wavelength from 1 pm at a magnetic field strength change of 0.25 mT. In addition, the temperature characteristics of the implemented magnetostrictive sensor were analyzed and an experimental factor of 1.5 compared to a reference fiber optic sensor was determined. T2 - 32nd DANUBIA ADRIA SYMPOSIUM on Advances in Experimental Mechanics CY - Starý Smokovec, Slovakia DA - 22.09.2015 KW - Self-diagnostic fiber optical sensor KW - Magnetostrictive metal coating KW - Magnetic field KW - Fiber bragg grating PY - 2016 DO - https://doi.org/10.1016/j.matpr.2016.03.038 SN - 2214-7853 VL - 3 IS - 4 SP - 1009 EP - 1013 AN - OPUS4-37131 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kotschate, Daniel A1 - Gohlke, Dirk A1 - Eisentraut, M. T1 - Reference block design for high resolution ultrasound immersion tank N2 - In respect of modern approaches in material sciences and highly increased requirements on materials on safety relevant components, quality management and non-destructive testing reclaims a steadily increased meaning. The destructive meaning of measuring the degree of purity is defined in DIN EN 10247 through metallurgical investigations, especially microsections. For and comparable, but non-destructive testing due ultrasonic testing, the material the SEP 1927 is a well-defined industry standard. A novel and alternative way of reference block construction was focused by this work. The proposed amendments, regarding the manufactoring and machining, are less time and cost consuming. Verified by measurements the presented reference block fits the same acoustical characteristics and the requirements of the guideline. T2 - World Conference on Non-Destructive Testing CY - Munich, Germany DA - 13.06.2016 KW - Immersion tank testing KW - SEP 1927 KW - Degree of purity KW - High resolution ultrasonic testing PY - 2016 AN - OPUS4-36850 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kotschate, Daniel A1 - Gohlke, Dirk A1 - Eisentraut, Mark T1 - Reference block design for high resolution ultrasound immersion tank N2 - In respect of modern approaches in material sciences and highly increased requirements on materials on safety relevant components, quality management and non-destructive testing reclaims a steadily increased meaning. The destructive meaning of measuring the degree of purity is defined in DIN EN 10247 through metallurgical investigations, especially microsections. For and comparable, but non-destructive testing due ultrasonic testing, the material the SEP 1927 is a well-defined industry standard. A novel and alternative way of reference block construction was focused by this work. The proposed amendments, regarding the manufacturing and machining, are less time and cost consuming. Verified by measurements the presented reference block fits the same acoustical characteristics and the requirements of the guideline. T2 - 19th World Conference on Non-Destructive Testing CY - Munich, Germany DA - 13.06.2016 KW - SEP 1927 KW - Degree of purity KW - High resolution ultrasonic testing KW - Immersion tank testing PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-368512 VL - 2016 SP - Paper X15, 1 EP - 4 AN - OPUS4-36851 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stockmann, Jörg M. A1 - Hertwig, Andreas A1 - Beck, Uwe T1 - Visualization of low-contrast surface modifications: thin films, printed pattern, laser-induced changes, imperfections, impurities, and degradation N2 - Industrial quality control (QC) nowadays requires the visualization of surface modifications from the macro-scopic to the microscopic or even nanoscopic scale. This is a prerequisite to the evaluation of functionality and reliability, the detection of defects and their separation of artefacts. The diversity of applications ranges from low-E glazings and solar panels, micro- and optoelectronics, micro- and smart devices to sensor-on-chip and lab-on-chip systems [1]. Optical microcopy (light, confocal laser scanning, white light interference) as established QC-tool is operated at normal incidence, i.e. p- and s-polarization are undistinguishable. Either light-intensity in terms of grey scale and colour or intensity-correlated effects of phase shifts are used. In case of ellipsometry, operated at oblique incidence, p- and s-polarization matter, and amplitude ratios and phase shifts upon reflection are measured. Hence, information content must be much higher. The visualization of surface modifications may be very challenging for coating/substrate systems of either al-most identical optical constants, e.g. transparent films on substrates of the same material, or minor film thick-ness, substance quantity and affected area, e.g. ultra-thin or island films. Ellipsometry gives access to the con-trast of intensity (I), amplitude ratio (Ψ), and phase shift (Δ) with nanometer-scaled vertical and micrometer-scaled lateral sensitivity, one is able to identify tiny changes within an unmodified surface. As both mapping ellipsometry (ME) and imaging ellipsometry (IE) are operated in the optical far-field, surface inspection is also possible on the macroscopic scale. Near the Brewster-angle of the bare, undamaged, clean, and fresh substrate, the contrast to add-on and sub-off features is superior. Fig. 1 shows three examples of ellipsometric imaging, i.e. a thin SnO:Ni film on SiO2/Si (Fig. 1a), a dried stain of an anti-body solution on cyclo-olefin-polymer (COP) shown in Fig. 1b, and a polyimide film residue on SiO2/Si (Fig. 1c). For all of these examples, ellipsometry provides much better contrast between substrate and surface modification than optical microscopy, sometimes primarily caused by the oblique incidence (Figs. 1a and 1c), in other cases related to the phase sensitivity of ellipsometry (Fig. 1b). Other examples are laser surface modifications and the corrosion of glass. In these cases, optical microscopy and IE yield to similar results, how-ever only ellipsometry gives access to modelling. Further investigated coating/substrate systems are 100Cr6 steel, native oxide on silicon, borosilicate glass, and the polymer polycarbonate with deposited films of graphene and ta-C:H, printed and dried pattern of liquids such as water, cleaning agents, and dissolved silicone. Besides imaging ellipsometry, referenced spectral ellipsometry (RSE) has been applied, combining the advantages of both optical microscopy (fast measurement) and ellipsometry (high sensitivity to tiny modifications). T2 - International Conference on Spectroscopic Ellipsometry (ICSE-7) CY - Berlin, Germany DA - 06.06.2016 KW - Ellipsometry KW - Thin films KW - Impurities KW - Degradation PY - 2016 AN - OPUS4-37068 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Standardization of fluorescence measurements: Design, development, validation, and fabrication of format-adaptable fluorescence standards for intensity, spectral, and temporal quantities N2 - Photoluminescence techniques are amongst the most widely used tools in the material and life sciences, with new and exciting applications continuously emerging, due to their many advantages like comparative ease of use, unique sensitivity, non-invasive character, and potential for multiplexing, remote sensing, and miniaturization. Drawbacks are , however, signals, that contain unwanted wavelength- and polarization contributions from instrument-dependent effects, which are time-dependent due to the aging of instrument components, and difficulties to measure absolute fluorescence intensities. Thus, there is a considerable need for standards for intensity, spectral, and temporal fluorescence quantities to meet the increasing need for instrument performance validation and global trends to harmonize physicochemical measurements. In this respect, instrument calibration strategies together with different types of fluorescence standards are presented as well as design concepts for robust, easy-to-use, and format-adaptable fluorescence standards useable for the determination of different fluorescence parameters and a broad variety of fluorescence techniques. T2 - SALSA-Kolloquien CY - Berlin, Germany DA - 07.06.2016 KW - Fluorescence KW - Standard KW - Quality assurance KW - Spectral correction KW - Quantum yield PY - 2016 AN - OPUS4-37070 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Siegel, G. A1 - Mockenhaupt, F.H.M.E. A1 - Behnke, A.-L. A1 - Ermilov, Eugeny A1 - Winkler, K. A1 - Pries, A.R. A1 - Malmsten, M. A1 - Hetzer, R. A1 - Saunders, R. A1 - Lindman, B. T1 - Lipoprotein binding to anionic biopolyelectrolytes and the effect of glucose on nanoplaque formation in arteriosclerosis and Alzheimer's disease N2 - Arteriosclerosis with its clinical sequelae (cardiac infarction, stroke, peripheral arterial occlusive disease) and vascular/Alzheimer dementia not only result in far more than half of all deaths but also represent dramatic economic problems. The reason is, among others, that diabetes mellitus is an independent risk factor for both disorders, and the number of diabetics strongly increases worldwide. More than one-half of infants in the first 6 months of life have already small collections of macrophages and macrophages filled with lipid droplets in susceptible segments of the coronary arteries. On the other hand, the authors of the Bogalusa Heart Study found a strong increase in the prevalence of obesity in childhood that is paralleled by an increase in blood pressure, blood lipid concentration, and type 2 Diabetes mellitus. Thus, there is a clear linkage between arteriosclerosis/Alzheimer's disease on the one hand and diabetes mellitus on the other hand. Furthermore, it has been demonstrated that distinct apoE isoforms on the blood lipids further both arteriosclerotic and Alzheimer nanoplaque formation and therefore impair flow-mediated vascular reactivity as well. Nanoplaque build-up seems to be the starting point for arteriosclerosis and Alzheimer's disease in their later full clinical manifestation. In earlier work, we could portray the anionic biopolyelectrolytes syndecan/perlecan as blood flow sensors and lipoprotein receptors in cell membrane and vascular matrix. We described extensively molecular composition, conformation, form and function of the macromolecule heparan sulfate proteoglycan (HS-PG). In two supplementary experimental settings (ellipsometry, myography),we utilized isolated HS-PG for in vitro nanoplaque investigations and isolated human coronary artery segments for in vivo tension measurements. With the ellipsometry-based approach, we were successful in establishing a direct connection on a molecular level between diabetes mellitus on the one side and arteriosclerosis/Alzheimer's disease on the other side. Application of glucose at a concentration representative for diabetics and leading to glycation of proteins and lipids, entailed a significant increase in arteriosclerotic and Alzheimer nanoplaque formation. IDLapoE4/E4 was by far superior to IDLapoE3/E3 in Plaque build-up, both in diabetic and non-diabetic patients. Recording vascular tension of flow-dependent reactivity in blood substitute solution and under application of different IDLapoE isoforms showed an impaired vasorelaxation for pooled IDL and IDLapoE4/E4, thus confirming the ellipsometric investigations. Incubation in IDLapoE0/E0 (apoE “knockout man”), however, resulted in a massive flowmediated contraction, also complemented by strongly aggregated nanoplaques. In contrast, HDL was shown to present a powerful protection against nanoplaque formation on principle, both in the in vitro model and the in vivo scenario on the endothelial cell membrane. The competitive interplay with LDL is highlighted through the flow experiment, where flow-mediated, HDL-induced vasodilatation remains untouched by additional incubation with LDL. This is due to the four times higher affinity for the proteoglycan receptor of HDL as compared to LDL. Taken together, the studies demonstrate that while simplistic, the ellipsometry approach and the endothelialmimicking proteoglycan-modified surfaces provide information on the initial steps of lipoprotein-related Plaque formation, which correlates with findings on endothelial cells and blood vessels, and afford insight into the role of lipoprotein deposition and Exchange phenomena at the onset of these pathophysiologies. KW - Diabetes mellitus and Alzheimer's disease KW - HS-PG flow sensor and lipoprotein receptor KW - Glucose and nanoplaque formation KW - IDLapoE3/E3 and IDLapoE4/E4 isoforms KW - HDL protection KW - β-amyloid (1–42) PY - 2016 DO - https://doi.org/10.1016/j.cis.2016.02.001 SN - 0001-8686 VL - 232 SP - 25 EP - 35 AN - OPUS4-37078 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liu, J.-Y. A1 - Hou, X.-N. A1 - Tian, Y. A1 - Jiang, L. A1 - Deng, S. A1 - Röder, B. A1 - Ermilov, Eugeny T1 - Photoinduced energy and charge transfer in a bis(triphenylamine)-BODIPY-C60 artificial photosynthetic system N2 - Triphenylamines (TPAs), boron dipyrromethenes (BODIPYs) and fullerenes C60 are excellent building blocks for the design of artificial photosynthetic systems. In the present work, we report the synthesis, characterization and detailed photophysical studies of a novel (TPA)2–BODIPY–C60 tetrad in polar and nonpolar solvents. The absorption spectrum of this compound covered virtually the entire visible Region (350–700 nm) and could be interpreted as a superposition of the spectra of individual components. Upon TPA-part excitation, a fast and very efficient excitation energy transfer (EET) delivers the excitation to the BODIPY moiety resulting in complete quenching of the TPA first excited singlet state as well as the appearance of the BODIPY fluorescence. The efficiency of EET process was estimated to be 1. Direct or indirect (via EET) excitation of the BODIPY-part of the tetrad is followed by photoinduced charge transfer to the charge-separated state BODIPY+–C60- irrespective of the solvent used. In polar N,N-dimethylformamide (DMF)charge recombination occurs directly to the ground state with the Charge recombination rate, kCR, slower than 108 s-1, whereas in nonpolar toluene (TOL) a small energy gap between the charge-separated state and first excited singlet state of the BODIPY moiety facilitates the back charge transfer process. The latter results in the appearance of thermally activated delayed fluorescence. The rate of charge separation was found to be ca. 2 times faster in TOL than in DMF. KW - Charge transfer KW - Energy transfer KW - Artificial photosynthesis KW - BODIPY KW - TPA KW - Fullerene C60 PY - 2016 DO - https://doi.org/10.1039/c6ra06841c SN - 2046-2069 VL - 6 IS - 62 SP - 57293 EP - 57305 AN - OPUS4-37080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fischer, Daniel A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Kormunda, M. A1 - Esser, N. T1 - Ellipsometric characterization of metal doped SnOx thin films for SPREE-based gas sensors N2 - Gas sensors are an important tool in various areas for example in industrial process control as well as Gas sensors are an important tool in various areas for example in industrial process control as well as safety applications or in research. A useful gas detector should be selective, precise, stable and cost-effective. In the present research a surface based gas detection technique is investigated using the SPR effect with ellipsometric readout. This technique is called surface plasmon resonance enhanced ellipsometry (SPREE). The sensor consists of a gold layer (40 nm) top-coated with a doped metal-oxide (M:SnOₓ, 5 nm). The coating is added by magnetron sputtering with doped targets with different doping concentrations. It could be shown that, without the top-coating, these type of sensors can detect various gases, e.g. CO, H2, O2, O3, He, N2, with sensitivities down to the ppm range (in air). The goal of the present study is to characterize the additional coating materials in dependence of the coating conditions. With the help of the doped-metal oxide, the sensitivity increases dramatically by a factor of 100. Additionally, a selectivity for specific gases is observed which depends on the doping conditions of the coating. Changing the properties of the plasma coating process and the doping metal gives access to a variety of different layers and enables us to find the best conditions. T2 - Leibniz Institut für Analytische Wissenschaften ISAS e.V. - Kolloqium CY - Berlin, Germany DA - 05.05.2016 KW - Ellipsometry KW - SPR effect KW - SnOx KW - Gas sensors PY - 2016 AN - OPUS4-37034 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pech, Anja A1 - Wilke, Olaf A1 - Horn, Wolfgang A1 - Jann, Oliver T1 - Analysis of very volatile organic compounds (VVOC) with thermal desorption GC-MS N2 - Most VVOC were rarely considered in the evaluation of construction products. (Salthammer, 2014) In Germany this will change because the latest version of the German AgBB scheme for health evaluation (2015) now include VVOC, e.g. ethyl acetate and ethanol. In this study selected compounds were tested with the procedure described in ISO 16017 and a method for measuring VVOC with thermal desorption was developed. Three different adsorbents Tenax TA, Carbograph 5TD and Carbopack X were tested to analyse VVOC according to ISO 16017. For the tested VVOC, Carbograph 5TD showed the best results under the chosen analytical conditions. T2 - Indoor Air 2016, The 14th international conference of Indoor Air Quality and Climate CY - Gent, Belgium DA - 03.07.2016 KW - Thermal desorption KW - VVOC KW - Carbograph 5TD KW - Carbopack X PY - 2016 SP - Paper 889, 1 EP - 2 AN - OPUS4-37035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deiting, D. A1 - Börno, Fabian A1 - Hanning, S. A1 - Kreyenschmidt, M. A1 - Seidl, T. A1 - Otto, M. T1 - Investigation on the suitability of ablated carbon as an internal standard in laser ablation ICP-MS of polymers N2 - The conventional quantitative method for the analysis of inorganic elements in polymer matrices is a complex and time consuming process that presents a significant risk for error. Typically, polymers are digested in a microwave oven or other devices under high temperature and pressure for several hours while employing different mixtures of high purity acids. In many cases, particularly when high concentrations of doped elements are present, the digestion is often incomplete and therefore the reproducibility depends strongly on the type of polymer and additives used. A promising alternative technology that allows for the direct analysis of these polymers without digestion is laser ablation ICP-MS. Due to a lack of available reference materials and the presence of matrix dependent effects, a precise calibration cannot be obtained. In order to compensate for the matrix dependent effects the use of internal standardization is necessary. In this study the correlation between the carbon released during the ablation process and the 13C signal detected by ICP-MS and its use as an internal standard are investigated. For this purpose, twenty-one virgin polymer materials are ablated; the released carbon is determined and correlated with the corresponding integrated 13C signal. The correlation resulted in a direct relationship between the ablated carbon and 13C signal demonstrating the potential ability to neglect at least some of the matrix dependent and transport effects which occur during the laser ablation of virgin polymers. KW - Laser ablation KW - ICP-MS KW - Polymer PY - 2016 DO - https://doi.org/10.1039/C6JA00020G SN - 0267-9477 VL - 31 IS - 8 SP - 1605 EP - 1611 PB - Royal Society of Chemistry CY - Cambridge, UK AN - OPUS4-37092 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weller, Andreas A1 - Zhang, Zeyu A1 - Slater, L. A1 - Kruschwitz, Sabine A1 - Halisch, M. T1 - Induced polarization and pore radius - a discussion N2 - Permeability estimation from spectral induced polarization (SIP) measurements is based on a fundamental premise that the characteristic relaxation time (t) is related to the effective hydraulic radius (reff) controlling fluid flow. The approach requires a reliable estimate of the diffusion coefficient of the ions in the electrical double layer. Others have assumed a value for the diffusion coefficient, or postulated different values for clay versus clay-free rocks. We examine the link between t and reff for an extensive database of sandstone sampleswhere mercury porosimetry data confirm that reff is reliably determined from a modification of the Hagen-Poiseuille equation assuming that the electrical tortuosity is equal to the hydraulic tortuosity. Our database does not support the existence of 1 or 2 distinct representative diffusion coefficients but instead demonstrates strong evidence for 6 orders of magnitude of variation in an apparent diffusion coefficient that is well correlated with both reff and the specific surface area per unit pore volume (Spor). Two scenarios can explain our findings: (1) the length-scale defined by t is not equal to reff and is likely much longer due to the control of pore surface roughness; (2) the range of diffusion coefficients is large and likely determined by the relative proportions of the different minerals (e.g. silica, clays) making up the rock. In either case, the estimation of reff (and hence permeability) is inherently uncertain from SIP relaxation time. T2 - IP Workshop 2016 CY - Aarhus, Denmark DA - 06.06.2016 KW - pore radius KW - mercury intrusion capillary pressure KW - spectral induced polarization KW - relaxation time PY - 2016 AN - OPUS4-37116 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kruschwitz, Sabine T1 - Measuring moisture in building material - an overview N2 - In Germany there is an existing built infrastructure worth about 50 trillion Euros. The expected lifetimes of individual structures are up to 100 years. Considerable costs (annually about 35 billion Euros, the trend continues upwards) are involved in order to maintain and rehabilitate both residential as well as transportation infrastructure buildings. Most damages we observe on our built infrastructure are moisture-induced processes. Consequently reliable moisture measurement tools a highly needed for meaningful building diagnosis investigations. The optimal moisture measuring technique would be non-destructive, fast, repeatable, reliable, independent of steel in the vicinity, the surface condition or possible salt loads of the material under test. Since this is unfortunately not the case for any non-destructive method, it is often very difficult to decide for users which method to use for the particular testing problem. The only standardized methods in Germany are the “direct” and destructive Darr- and the CM tests. Although they can be highly accurate (when handled with care during the sampling), they deliver only punctual information and cannot be used for monitoring. The other, non-destructive methods are based on the change in humidity-dependent physical material properties. The underlying physics, their particular advantages and disadvantages are discussed in this paper. T2 - Building Safety Symposium CY - Hong Kong, China DA - 22.04.2016 KW - Non-destructive methods KW - Moisture measuring KW - Electrical methods KW - Microwave PY - 2016 AN - OPUS4-37118 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen T1 - Dispersities of Polyesters of Various Diphenols Prepared by Irreversible Polycondensations N2 - Polyesters of bisphenol-A, bisphenol-P, catechol, and sebacic acid are prepared and different synthetic methods are compared. The diphenols are condensed with sebacoyl chloride either in dichloromethane/pyridine or in refl uxing chlorobenzene without HCl-acceptor. Further- more, bisphenol-A acetate is polycondensed with sebacic acid in bulk. All experiments are worked up so that fractionation is avoided. The extent of cyclization is estimated by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) and the molar mass distribution by size exclusion chromatography (SEC). Polycondensations in solution yield larger fractions of cyclics and higher dispersities (up to 11). Polycondensations in bulk give lower fractions of cycles and dispersities from 4.6 to 6.3 for high molar mass polyesters or 2.8 to 3.5 for low molar mass products. Characteristic curves describing the dependence of the dispersity on the initial monomer concentration are elaborated. KW - cyclization KW - dispersity KW - mass spectra KW - polycondensation KW - polyesters PY - 2016 DO - https://doi.org/10.1002/macp.201600004 IS - 217 SP - 1361 EP - 1369 PB - Wiley-VCH Verlag CY - Weinheim AN - OPUS4-37120 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, Ralf A1 - Weigert, Florian A1 - Lesnyak, V. A1 - Leubner, S. A1 - Lorenz, T. A1 - Behnke, Thomas A1 - Dubavik, A. A1 - Joswig, J.-O. A1 - Resch-Genger, Ute A1 - Gaponik, N. A1 - Eychmüller, A. ED - Resch-Genger, Ute ED - Schneider, Ralf T1 - pH and concentration dependence of the optical properties of thiol-capped CdTe nanocrystals in water and D2O N2 - The optical properties of semiconductor nanocrystals (SC NCs) are largely controlled by their size and surface chemistry, i.e., the chemical composition and thickness of inorganic passivation shells and the chemical nature and number of surface ligands as well as the strength of their bonds to surface atoms. The latter is particularly important for CdTe NCs, which – together with alloyed CdₓHg₁₋ₓTe – are the only SC NCs that can be prepared in water in high quality without the need for an additional inorganic passivation shell. Aiming at a better understanding of the role of stabilizing ligands for the control of the application-relevant fluorescence features of SC NCs, we assessed the influence of two of the most commonly used monodentate thiol ligands, thioglycolic acid (TGA) and mercaptopropionic acid (MPA), on the colloidal stability, photoluminescence (PL) quantum yield (QY), and PL decay behavior of a set of CdTe NC colloids. As an indirect measure for the strength of the coordinative bond of the ligands to SC NC surface atoms, the influence of the pH (pD) and the concentration on the PL properties of these colloids was examined in water and D₂O and compared to the results from previous dilution studies with a set of thiol-capped Cd₁₋ₓHgₓTe SC NCs in D₂O. As a prerequisite for these studies, the number of surface ligands was determined photometrically at different steps of purification after SC NC synthesis with Ellman’s test. Our results demonstrate ligand control of the pH-dependent PL of these SC NCs, with MPA-stabilized CdTe NCs being less prone to luminescence quenching than TGA-capped ones. For both types of CdTe colloids, ligand desorption is more pronounced in H₂O compared to D₂O, underlining also the role of hydrogen bonding and solvent molecules. KW - Quantum dots KW - Fluorescence KW - Ligand analysis KW - Nano particles PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-371253 DO - https://doi.org/10.1039/c6cp03123d VL - 18 IS - 28 SP - 19083 EP - 19092 PB - RSC CY - Cambridge AN - OPUS4-37125 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maul, R. A1 - Schloß, Svenja A1 - Herz, C. A1 - Lamy, E. A1 - Koch, Matthias A1 - Rohn, S. T1 - Phomopsins in legumes - a multidimensional approach N2 - Fungal secondary metabolites such as phomopsin A (PHO-A) produced by the fungus Diaporthe toxica are referred to as “emerging” mycotoxins. Recently, we developed a biosynthetic approach to gain access to 15N-isotopically labelled PHO-A as internal standard (IS) for PHO-A matrix independent quantification of PHO-A in various commodities. Aim of the present work was to elucidate the applicability of the new IS for accurate quantification and to investigate the phomopsin formation on various legume seeds as well as plant material. In summary, the applicability of the SIDA-HPLC-MS/MS method could be proven and the potential of D. toxica to produce high amounts of phomopsins under unfavorable conditions on lupins and other legume seeds could be shown. Moreover, a novel toxic methylated PHO-A derivative was unveiled in natural samples infested with D. toxica. T2 - 38. Mycotoxin-Workshop CY - Berlin, Germany DA - 02.05.2016 KW - Phomopsin-Derivate KW - Leguminosen KW - Stabilisotopenverdünnungsanalyse KW - HPLC-MS/MS KW - HRMS-Identifizierung KW - Toxizität PY - 2016 AN - OPUS4-37056 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Biyikal, Mustafa A1 - Gawlitza, Kornelia A1 - Dropa, T. A1 - Urban, M. A1 - Costero, A. M. A1 - Martínez-Mánez, Ramon A1 - Rurack, Knut T1 - A rapid and sensitive strip-based quick test for nerve agents Tabun, Sarin, and Soman using BODIPY-modified silica materials N2 - Test strips that in combination with a portable fluorescence reader or digital camera can rapidly and selectively detect chemical warfare agents (CWAs) such as Tabun (GA), Sarin (GB), and Soman (GD) and their simulants in the gas phase have been developed. The strips contain spots of a hybrid indicator material consisting of a fluorescent BODIPY indicator covalently anchored into the channels of mesoporous SBA silica microparticles. The fluorescence quenching response allows the sensitive detection of CWAs in the μg m−3 range in a few seconds. KW - Chemical warfare agents KW - Fluorescence KW - Hybrid sensor materials KW - Nerve gases KW - Test strip analysis PY - 2016 DO - https://doi.org/10.1002/chem.201601269 SN - 0947-6539 SN - 1521-3765 VL - 22 IS - 32 SP - 11138 EP - 11142 PB - Wiley CY - Online Library AN - OPUS4-37063 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Behnke, Thomas A1 - Moser, Marko A1 - Quevedo, Pablo A1 - Nirmalananthan-Budau, Nithiya A1 - Weigert, Florian A1 - Würth, Christian A1 - Hoffmann, Katrin A1 - Ermilov, Eugeny A1 - Pauli, Jutta T1 - Simple methods, validation concepts, and reference materials for the characterization of functional nanomaterials and microparticles N2 - The surface chemistry / functionalization of nanomaterials and microparticles largely controls the stability of these materials as well as their solubility and subsequent biofunctionalization and their interactions with biological systems. Moreover, in the case of some nanomaterials like semiconductor quantum dots or lanthanide-based upconversion nanocrystals, the ligand shell strongly affects their optical properties, e.g., via passivation of surface states and traps that favor luminescence quenching or the protection of surface atoms from quenching water molecules. This renders analytical methods for the quantification of surface groups like functionalities very important. Targets of broad interest are here amino, carboxyl, alkine and maleimide groups used for common bioconjugation reactions and typical ligands like thiols and polyethylene glycol (PEG) molecules of varying length, used for the tuning of material hydrophilicity and biocompatibility, minimization of unspecific interactions, prevention of biofouling, and enhancement of blood circulation times as well as surface-bound biomolecules like streptavidin or other biomolecules relevant e.g., for diagnostic assays. Here, we focus on simple optical methods relying on standard laboratory instrumentation, validated by method comparison and/or mass balances and present examples for their use for the characterization of different types of nanomaterials and microparticles. T2 - Innovationsforum Senftenberg CY - Senftenberg, Germany DA - 01.06.2016 KW - Surface chemistry KW - Functional group analysis KW - Thiol assay KW - Fluorescence KW - Nanomaterial KW - Nanoparticle KW - PEG KW - Ligand KW - Semiconductor quantum dot KW - Quantum yield KW - Quantification KW - Method validation KW - Integrating sphere spectroscopy KW - Fluorescence standard PY - 2016 N1 - Geburtsname von Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. - Birth name of Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. AN - OPUS4-37111 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Applications and challenges of luminescence-based detection methods in the life and material sciences N2 - Luminescence-based detection methods, ranging from fluorescence spectroscopy for photophysical and mechanistic studies over sensing applications, chromatographic separation techniques and the microarray technology with fluorescence detection to fluorescence microscopy, flow cytometry, single molecule spectroscopy, and molecular imaging to integrating sphere spectroscopy, are among the most widely used methods in the life and material sciences. This is due to e.g., their unique sensitivity enabling the detection of single molecules, potential for multiplexing, ease of combination with spatial resolution, and suitability for remote sensing. Many of these advantages are closely linked to the choice of suitable molecular and nanoscale fluorescent reporters, typically required for signal generation. This includes organic dyes without and with sensor function, fluorophore-encoded polymeric and silica nanoparticles as well as nanocrystalline systems like semiconductor quantum dots and upconversion phosphors, emitting in the visible (vis), near-infrared (NIR), and IR (infrared). Current challenges present the environment sensitivity of most fluorophores, rendering fluorescence spectra, measured intensities/fluorescence quantum yields, and fluorescence decay kinetics matrix-dependent, and instrument-specific distortions of measured fluorescence signals that need to be considered for quantification and comparability of data, particularly fluorescence spectra. Here, current applications of luminescence-based methods and different types of reporters will be presented. In this context, suitable spectroscopic tools for the characteri-zation of the optical properties of fluorescent reporters and fluorophore-encoded microparticles, analytical tools for the determination of the surface chemistry of different types of particles, and different multiplexing strategies will be discussed. T2 - 9th Meeting of Engineering of Functional Interfaces CY - Wildau,Germany DA - 03.07.2016 KW - Fluorescence KW - Multiplexing KW - Lifetime KW - Nanomaterial KW - Nanoparticle KW - PEG KW - Ligand KW - Semiconductor quantum dot KW - Quantum yield KW - Quantification KW - Upconversion nanoparticle KW - Integrating sphere spectroscopy KW - NIR KW - IR KW - Fluorescence standard KW - Calibration PY - 2016 AN - OPUS4-37112 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaenisch, Gerd-Rüdiger A1 - Müller, Christina A1 - Pavlovich, Mato A1 - Bartsch, Ludwig A1 - Rosenthal, Martina A1 - Holstein, R. T1 - Simulation and experimental results of manual UT-testing of hollow wheel set axles during the education of operators N2 - The reliability of wheel set axle testing is of high importance because small discontinuities caused during manufacturing or rock fall impacts during operation might cause growing cracks during the operation load cycles. While most of the axles are tested by automated UT-systems today, the basic education of railway NDT operators is still manual testing providing the basic understanding and skills for the operators. In Germany it is a common rule that NDT operators in the railway branch need to refresh their knowledge and skills every five years including a refresh examination. The testing results from these exercises and from a parallel round robin test have been sampled at the DGZfP Railway Education Centre in Wittenberge for a period of about 5 years. The results of the operators written in test record sheets were compared with the “true” test crack or notch position in the axles used for examination. In this way the testing results could be categorized into “hits” and “misses” and the “hits” were further evaluated due to correct position and adequate amplitude height. Considering some thousand indications documented by the operators during the refresh examination and comparing transition bow, shaft and seat it was a highlight to see that the operators reach their best detection rate in the transition bow of the wheel axle set while this is often the most difficult part concerning the UT-echoes. Fortunately this is due to their raised awareness in the transition bow region because this is the most dangerous region with respect to fracture mechanics. For two selected axles the experimental set up of 45° and 70° inward and outward UT-testing were also simulated showing clearly the difficulties of the UT-echoes detection of some specific test defects. T2 - XXII Saint-Petersburg Conference on Ultrasonic Testing of Metals and Advanced Materials (UTM 2016) CY - St. Petersburg, Russia DA - 24.05.2016 KW - Ultrasound KW - Manual testing KW - NDT reliability KW - Fault tree analysis KW - Education of NDT personnel PY - 2016 AN - OPUS4-37013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF ED - Halisch, M. ED - Kruschwitz, Sabine ED - Schmitt, M. ED - Weller, Andreas T1 - Quantification of rock structures with high resolution X-ray μ-CT for laboratory SIP measurements N2 - Spectral Induced Polarization (SIP) measurements are used in many different ways to characterize natural rocks and soils. Main foci of interest are the enhanced characterization of the causes of IP-effects in clastic rocks (especially sandstones), the interactions between the matrix-fluid-system and within the electrical double layers as well as the correlation with “classical” petrophysical parameters, such as specific surface area, permeability, mercury intrusion capillary pressure (MICP) and others. Nevertheless, for all of these investigations, knowledge of the inner structure of the sample material is essential in order to create reliable and validated models as well as to interpret and to assess the data most completely. Unfortunately, many of the methods used, to get access to the inner structure of rocks are destructive (e.g. MICP, thin sectioning, etc.) and the valuable sample is lost. In addition, data is either of volume integrated nature or only available for the 2D case and the usage of sister cores does not necessarily lead to reliable results. In this paper, the authors showcase the possibilities of non-destructive and three dimensional X-ray computed tomography and of enhanced image analysis capabilities for the quantification of rock structures at the pore scale. T2 - IP Workshop 2016 CY - Aarhus, Denmark DA - 06.06.2016 KW - μ-CT imaging, KW - Rock structure KW - Digital image analysis KW - Pore geometry KW - Grain geometry KW - SIP PY - 2016 SP - 1 EP - 4 CY - Aarhus, Denmark AN - OPUS4-37024 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Götschel, S. A1 - Höhne, Christian A1 - Kolkoori, Sanjeevareddy A1 - Mitzscherling, Steffen A1 - Prager, Jens A1 - Weiser, M. T1 - Ray tracing boundary value problems: simulation and SAFT reconstruction for ultrasonic testing N2 - The application of advanced imaging techniques for the ultrasonic inspection of inhomogeneous anisotropic materials like austenitic and dissimilar welds requires information about acoustic wave Propagation through the material, in particular travel times between two Points in the material. Forward ray tracing is a popular approach to determine traveling paths and arrival times but is ill suited for inverse problems since a large number of rays have to be computed in order to arrive at prescribed end points. In this contribution we discuss boundary value problems for acoustic rays, where the ray path between two given points is determined by solving the Eikonal equation. The implementation of such a two Point boundary value ray tracer for sound field simulations through an austenitic weld is described and its efficiency as well as the obtained results are compared to those of a forward ray tracer. The results are validated by comparison with experimental results and commercially available UT simulation tools. As an application, we discuss an implementation of the method for SAFT (Synthetic Aperture Focusing Technique) reconstruction. The ray tracer calculates the required travel time through the anisotropic columnar grain structure of the austenitic weld. There, the formulation of ray tracing as a boundary value Problem allows a straightforward derivation of the ray path from a given transducer Position to any pixel in the reconstruction area and reduces the computational cost considerably. T2 - 19th World Conference on Non-Destructive Testing 2016 CY - München, Germany DA - 13.06.2016 KW - Ultrasonic testing KW - SAFT KW - Ray tracing KW - Simulation PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370494 UR - www.ndt.net/?id=19437 SP - ID 19437, 1 EP - 8 AN - OPUS4-37049 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Boehm, Rainer A1 - Brackrock, Daniel A1 - Montag, Hans-Joachim A1 - Heckel, Thomas T1 - What is the benefit of the total focussing method and full matrix capture for ultrasonic imaging using the phased array technique N2 - In the last two decades automated ultrasonic inspection devices took over a lot of applications that prior have been carried out using manual inspection with the evaluation of A-scans only. In parallel phased array systems have been developed and brought to the market which offer detailed and fast control over the sound field. When applying automated inspection phased array systems for UT measurements imaging of the recorded data in combination with the probe positioning data is used for the evaluation of inspections. B-Scan, C-Scan and S-Scan images are typically used with this setup. For more sophisticated applications with linear arrays echo tomography and syntethic aperture focusing technique (SAFT) are well known methods and often applied for high resolution image reconstruction. Since channel count of phased array systems is constantly rising, matrix arrays with up to 256 elements entered the market. Signal processing in the matrix domain became 3D. Since some years the Total Focusing Method (TFM) is an additional imaging tool for these type of application. It is based on the Full Matrix Capture (FMC) using the elements of phased array probes as separate transmitters and receivers. In this contribution we discuss the common ground of SAFT and TFM as well as the differences between these imaging tools. The combined use of automated inspection, matrix arrays and signal processing for high resolution measurements is a challenging task where a very long parameter list has to be taken into account. Under which conditions which elements of the full matrix should be taken for the reconstruction for best results? Based on examples taken from measured and simulated echo signals it will be shown how image resolution can be optimized in dependence of different parameters like the distance between transmitters and receivers and their directivity patterns, the depth of echo source and the specimen geometry. T2 - 19th World Conference on Non-Destructive Testing CY - Munich, Germany DA - 13.06.2016 KW - Ultrasonic testing KW - Ultrasonic imaging KW - Phased array KW - Total focussing method KW - Full matrix capture PY - 2016 UR - https://www.wcndt2016.com/programme AN - OPUS4-37051 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Götschel, S. A1 - Weiser, M. A1 - Höhne, Christian A1 - Kolkoori, Sanjeevareddy A1 - Mitzscherling, Steffen A1 - Prager, Jens T1 - Ray tracing boudary value problems: simulation and SAFT reconstruction for ultrasonic testing N2 - The application of advanced imaging techniques for the ultrasonic inspection of inhomogeneous anisotropic materials like austenitic and dissimilar welds requires information about acoustic wave propagation through the material, in particular travel times between two points in the material. Forward ray tracing is a popular approach to determine traveling paths and arrival times but is ill suited for inverse problems since a large number of rays have to be computed in order to arrive at prescribed end points. In this contribution we discuss boundary value problems for acoustic rays, where the ray path between two given points is determined by solving the eikonal equation. The implementation of such a two point boundary value ray tracer for sound field simulations through an austenitic weld is described and its efficiency as well as the obtained results are compared to those of a forward ray tracer. The results are validated by comparison with experimental results and commercially available UT simulation tools. As an application, we discuss an implementation of the method for SAFT (Synthetic Aperture Focusing Technique) reconstruction. The ray tracer calculates the required travel time through the anisotropic columnar grain structure of the austenitic weld. There, the formulation of ray tracing as a boundary value problem allows a straightforward derivation of the ray path from a given transducer position to any pixel in the reconstruction area and reduces the computational cost considerably. T2 - 19th World Conference on Non-Destructive Testing 2016 CY - Munich, Germany DA - 13.06.2016 KW - Ultrasonic testing KW - SAFT KW - Ray tracing KW - Simulation PY - 2016 UR - www.ndt.net/?id=19437 UR - https://www.wcndt2016.com/portals/wcndt/bb/Fr1H4.pdf AN - OPUS4-37052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Habel, Wolfgang R. A1 - Krebber, Katerina A1 - Daum, Werner T1 - Results in standardization of FOS to support the use of SHM systems N2 - Measurement and data recording systems are important parts of a holistic Structural Health Monitoring (SHM) system. New sensor technologies such as fiber-optic sensors are often used; however, standards (or at least guidelines) are not yet available or internationally approved. This lack in standardization makes the acceptance of FOS technologies in complex SHM systems substantially difficult. A standard family for different FOS technologies is therefore being developed that should help to design SHM systems in an optimal way. International standardization activities take place in several standardization bodies such as IEC and ASTM, and within SHM societies such as ISHMII. The paper reports on activities in standardization of fiber-optic sensors, on results already achieved, and on newly started projects. Combined activities of fiber sensor experts and SHM experts from Civil Engineering are presented. These contributions should help owners of structures as well as developers of sensors and monitoring systems to select effective and validated sensing technologies. Using these standards, both parties find recommendations how to proceed in development of SHM systems to evaluate the structural behavior based on e.g. standardized fiber optic sensors, and to derive necessary measures, e.g. the optimal maintenance strategy. T2 - Sixth European Workshop on Optical Fibre Sensors CY - Limerick, Ireland DA - 30.05.2016 KW - Fiber-optic sensor KW - Standard KW - Temperature KW - Strain KW - Monitoring KW - Structural health KW - Application PY - 2016 DO - https://doi.org/10.1117/12.2236863 SN - 0277-786X VL - 9916 SP - 991625-1 EP - 991625-4 AN - OPUS4-37053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hutchinson, R. A1 - Jakubowski, Norbert A1 - Traub, Heike A1 - Esteban-Fernandez, Diego A1 - Wilkins, J. A1 - Summerfield, L. A1 - O´Connor, C. A1 - McLachlin, K. T1 - The NWRiMAGE - an elemental microscope N2 - The NWRiMAGE provides unique technologies for high-speed imaging with genuine sub-micron ablation. In March 2015 ESI installed the first NWR iMAGE at the Bundesanstalt für Materialforschung und –prüfung (BAM) in Berlin, and since then it has undergone extensive use in bio-imaging. The Dual Concentric Injector (DCI), a new interface between laser and plasma, has been integrated into ESI´s TwoVol2 ablation cell. This technology was developed in collaboration with the University of Loughborough, and provides single shot transition at the ICP-MS of < 20 ms with high sample transport efficiency, giving superior signals above background and improve spatial resolution capability. Here we describe some data showing ultra-fast transitions of single shot ablation, sub-micron ablation experiments and rapid acquired imaging. T2 - 13th European Workshop on Laser Ablation CY - Ljubljana, Slovenia DA - 12.07.2016 KW - Laser ablation KW - Trace element KW - Imaging PY - 2016 AN - OPUS4-36999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Halisch, M. A1 - Kruschwitz, Sabine A1 - Schmitt, M. A1 - Weller, Andreas T1 - Quantification of rock structures with high resolution X-Ray μ-CT for laboratory SIP measurements N2 - Spectral Induced Polarization (SIP) measurements are used in many different ways to characterize natural rocks and soils. Main foci of interest are the enhanced characterization of the causes of IP-effects in clastic rocks (especially sandstones), the interactions between the matrix-fluid-system and within the electrical double layers as well as the correlation with “classical” petrophysical parameters, such as specific surface area, permeability, mercury intrusion capillary pressure (MICP) and others. Nevertheless, for all of these investigations, knowledge of the inner structure of the sample material is essential in order to create reliable and validated models as well as to interpret and to assess the data most completely. Unfortunately, many of the methods used, to get access to the inner structure of rocks are destructive (e.g. MICP, thin sectioning, etc.) and the valuable sample is lost. In addition, data is either of volume integrated nature or only available for the 2D case and the usage of sister cores does not necessarily lead to reliable results. In this paper, the authors showcase the possibilities of non-destructive and three dimensional X-ray computed tomography and of enhanced image analysis capabilities for the quantification of rock structures at the pore scale. T2 - IP Workshop 2016 CY - Aarhus, Denmark DA - 06.06.2016 KW - SIP KW - μ-CT imaging KW - Rock structure KW - Digital image analysis KW - Pore geometry KW - Grain geometry PY - 2016 AN - OPUS4-37000 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weller, Andreas A1 - Zhang, Zeyu A1 - Slater, L. A1 - Kruschwitz, Sabine A1 - Halisch, M. T1 - Induced polarization and pore radius – a discussion N2 - Permeability estimation from spectral induced polarization (SIP) measurements is based on a fundamental premise that the characteristic relaxation time (t) is related to the effective hydraulic radius (reff) controlling fluid flow. The approach requires a reliable estimate of the diffusion coefficient of the ions in the electrical double layer. Others have assumed a value for the diffusion coefficient, or postulated different values for clay versus clay-free rocks. We examine the link between t and reff for an extensive database of sandstone samples where mercury porosimetry data confirm that reff is reliably determined from a modification of the Hagen-Poiseuille equation assuming that the electrical tortuosity is equal to the hydraulic tortuosity. Our database does not support the existence of 1 or 2 distinct representative diffusion coefficients but instead demonstrates strong evidence for 6 orders of magnitude of variation in an apparent diffusion coefficient that is well correlated with both reff and the specific surface area per unit pore volume (Spor). Two scenarios can explain our findings: (1) the length-scale defined by t is not equal to reff and is likely much longer due to the control of pore surface roughness; (2) the range of diffusion coefficients is large and likely determined by the relative proportions of the different minerals (e.g. silica, clays) making up the rock. In either case, the estimation of reff (and hence permeability) is inherently uncertain from SIP relaxation time. T2 - IP Workshop 2016 CY - Aarhus, Denmark DA - 06.06.2016 KW - Pore radius KW - Mercury intrusion capillary pressure KW - Spectral induced polarization KW - Relaxation time PY - 2016 AN - OPUS4-37003 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weller, Andreas A1 - Zhang, Zeyu A1 - Slater, L. A1 - Kruschwitz, Sabine A1 - Halisch, M. T1 - Induced polarization and pore radius - a discussion N2 - Permeability estimation from spectral induced polarization (SIP) measurements is based on a fundamental premise that the characteristic relaxation time (t) is related to the effective hydraulic radius (reff) controlling fluid flow. The approach requires a reliable estimate of the diffusion coefficient of the ions in the electrical double layer. Others have assumed a value for the diffusion coefficient, or postulated different values for clay versus clay-free rocks. We examine the link between t and reff for an extensive database of sandstone samples where mercury porosimetry data confirm that reff is reliably determined from a modification of the Hagen- Poiseuille equation assuming that the electrical tortuosity is equal to the hydraulic tortuosity. Our database does not support the existence of 1 or 2 distinct representative diffusion coefficients but instead demonstrates strong evidence for 6 orders of magnitude of variation in an apparent diffusion coefficient that is well correlated with both reff and the specific surface area per unit pore volume (Spor). Two scenarios can explain our findings: (1) the length-scale defined by t is not equal to reff and is likely much longer due to the control of pore surface roughness; (2) the range of diffusion coefficients is large and likely determined by the relative proportions of the different minerals (e.g. silica, clays) making up the rock. In either case, the estimation of reff (and hence permeability) is inherently uncertain from SIP relaxation time. T2 - IP Workshop 2016 CY - Aarhus, Denmark DA - 06.06.2016 KW - Pore radius KW - Mercury intrusion capillary pressure KW - Spectral induced polarization KW - Relaxation time PY - 2016 SP - 1 EP - 4 AN - OPUS4-37004 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kruschwitz, Sabine T1 - Moisture measurement methods N2 - Moisture can cause imperfect sealings, faulty roof constructions, cracks and other kind of damages. For measuring the moisture in construction materials like concrete and screed, there are destructive(direct) and non-destructive(indirect) methods, that can be used. This presentation gives an overview and a comparison of these methods. T2 - Nondestructive Testing and Evaluation in Civil Engineering and Surveying - Advanced Training 2016 CY - Berlin, Germany DA - 14.07.2016 KW - Moisture KW - Non-destructive testing PY - 2016 AN - OPUS4-37005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heckel, Thomas A1 - Boehm, Rainer A1 - Spruch, W. A1 - Jacob, S. T1 - Increasing the sensitivity of ultrasonic phased array wheel set axle inspection by using signal processing N2 - Der einwandfreie Zustand der Radsätze von Schienenfahrzeugen ist von größter Bedeutung für den sicheren Betrieb. Die Radsatzwellen werden durch eine große Zahl von Lastwechseln individuell unterschiedlich beansprucht. Dabei spielen viele Einflüsse wie äußere statische und dynamische Lasten, innere Lasten aufgrund von Unwuchten und inneren Spannungen und Umweltbedingungen entscheidende Rollen. Eine regelmäßige Prüfung ist daher obligatorisch. BTD entwickelt im Rahmen eines MNPQ-Projektes in Kooperation mit der BAM eine Phased Array Technik zur automatisierten Prüfung von Radsatzwellen im eingebauten Zustand. Die schwierigen Ankoppelbedingungen aufgrund der begrenzten Zugänglichkeit, der komplexen Geometrie sowie Farbschichten und Schmutz auf der Radsatzwelle stellen hierbei große Herausforderungen dar. Zu deren Bewältigung werden neben optimierten Prüfköpfen, einer in die Wasservorlaufstrecke integrierten akustischen Linse und einer speziellen Ankoppeltechnik auch Signalverarbeitungsalgorithmen eingesetzt. Die Darstellung der Signalverarbeitung ist der Schwerpunkt dieses Beitrages. Mit Hilfe von Messdatensätzen präparierter Testwellen werden verschiedene Algorithmen erprobt und hinsichtlich der Stabilität, dem Verhalten bezüglich der Ankoppelschwankungen und veränderter Wellengeometrien und der Fähigkeit zur automatischen Unterscheidung von Fehler- und Formanzeigen bewertet. Letztlich wird die beste Lösung im entwickelten Prüfsystem eingesetzt. T2 - 19th WCNDT - World Conference on Non Destructive Testing CY - München, Germany DA - 13.06.2016 KW - Ultrasound KW - Phased array KW - Wheelset KW - Railway KW - Signal processing PY - 2016 AN - OPUS4-37008 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kruschwitz, Sabine A1 - Strangfeld, Christoph A1 - Wöstmann, Jens T1 - Measuring screed moisture with EM methods – a comparison of capacitive handheld and microwave resonator probes N2 - We have compared the performance of the typical Darr and CM moisture testing techniques, which are destructive with several non-destructive testing techniques on two types of floor screeds. In case of cement based screeds these destructive tests failed to deliver reliable results. Moreover, our measurements indicate significantly different drying and moisture transport behavior for the investigated cement based and calcium-sulphate based screeds. Whereas we have strong with depth decreasing moisture gradients in the CT material, we observe in the penetrated volumes of our ndt methods basically no clear moisture gradient in the CA samples. The findings with ndt methods could be supported by moisture gradient studies with nuclear magnetic resonance measurements. T2 - 11th Int. Conference on electromagnetic wave interaction with water and moist substances CY - Florenz, Italy DA - 23.5.2016 KW - Moisture KW - Screed KW - Microwave KW - Nuclear magnetic resonance PY - 2016 SP - 77 EP - 84 AN - OPUS4-36674 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Carvalho, Margarida A1 - Schneider, Rudolf A1 - Madder, A. T1 - Addressable Immunoarrays: Protein-Nucleic Acid Conjugate Production N2 - Immunoassays are analytical methods used to track both clinical and environmental parameters. Antibodies or other proteins with similar recognizing activity, are employed, often immobilized onto a modified surface. Addressable microarrays are based on single-stranded DNA oligonucleotides which are normally used to detect aptamers or relevant gene sequences. The use of antibody-oligonucleotide conjugates allows non-directed antibody immobilization from an immunoassay to be converted into DNA hybridization events on the array. Consequently, the diagnostics platform is multiplexed and addressable. Figure 1 is a model representation of the whole biosensor construct. In brief, a surface is coated with streptavidin, and decorated with biotin-modified oligonucleotides of a controlled size and known sequence. These oligonucleotides on the surface also contain a furan motif, which upon irradiation and in the presence of a photosensitizer, is oxidized via single oxygen to a reactive intermediate which crosslinks the immediate opposing base when hybridized with its complementary strand [1]. Antibody-oligonucleotides conjugates still display several concerns due to their heterogeneicity, difficulty of characterization and high price [2]. The being the case, we aim at developing stable, robust, reproducible and well characterized quimeras for the application on te above described immunoarray. Mild chemical conditions are crucial for the antibody stability, therefore bivalent crosslinkers have been employed [2]. Even though the use of these bilinkers is standard for other substrate conjugation (i.e., enzymes, drug payloads, etc.), there is no literature available on the conjugation of small oligonucleotides (< 30 mer) to antibodies using this method. Several protein-nucleic acid conjugates have been therefore developed, and successfully characterized using MALDI-ToF and gel electrophoresis techniques. T2 - SO2S - The singlet Oxygen Strategy - Final Network Meeting CY - Gent, Belgium DA - 14.06.2016 KW - Antibodies KW - Immunoarrays KW - Nucleic acids PY - 2016 AN - OPUS4-36680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meiling, T. A1 - Cywinski, P. A1 - Bald, Ilko T1 - White carbon: Fluorescent carbon nanoparticles with tunable quantum yield in a reproducible green synthesis N2 - In this study, a new reliable, economic, and environmentally-friendly one-step synthesis is established to obtain carbon nanodots (CNDs) with well-defined and reproducible photoluminescence (PL) properties via the microwave-assisted hydrothermal treatment of starch and Tris-acetate-EDTA (TAE) buffer as carbon sources. Three kinds of CNDs are prepared using different sets of above mentioned starting materials. The as-synthesized CNDs: C-CND (starch only), N-CND 1 (starch in TAE) and N-CND 2 (TAE only) exhibit highly homogenous PL and are ready to use without need for further purification. The CNDs are stable over a long period of time (>1 year) either in solution or as freeze-dried powder. Depending on starting material, CNDs with PL quantum yield (PLQY) ranging from less than 1% up to 28% are obtained. The influence of the precursor concentration, reaction time and type of additives on the optical properties (UV-Vis absorption, PL emission spectrum and PLQY) is carefully investigated, providing insight into the chemical processes that occur during CND formation. Remarkably, upon freeze-drying the initially brown CND-solution turns into a non-fluorescent white/slightly Brown powder which recovers PL in aqueous solution and can potentially be applied as fluorescent marker in bio-imaging, as a reduction agent or as a photocatalyst. KW - Carbon dots KW - Quantum yield KW - Fluorescence KW - Nanoparticles PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367204 DO - https://doi.org/10.1038/srep28557 VL - 6 SP - Article 28557, 1 EP - 9 PB - Nature Publishing Group AN - OPUS4-36720 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ehlert, Christopher A1 - Holzweber, Markus A1 - Lippitz, Andreas A1 - Unger, Wolfgang A1 - Saalfrank, Peter T1 - A detailed assignment of NEXAFS resonances of imidazolium based ionic liquids N2 - In Near Edge X-Ray Absorption Fine Structure (NEXAFS) spectroscopy X-Ray photons are used to excite tightly bound core electrons to low-lying unoccupied orbitals of the system. This technique offers insight into the electronic structure of the system as well as useful structural information. In this work, we apply NEXAFS to two kinds of imidazolium based ionic liquids ([CnC₁im]⁺[NTf₂]⁻ and [C₄C₁im]⁺[I]⁻). A combination of measurements and quantum chemical calculations of C K and N K NEXAFS resonances is presented. The simulations, based on the transition potential density functional theory method (TP-DFT), reproduce all characteristic features observed by the experiment. Furthermore, a detailed assignment of resonance features to excitation centers (carbon or nitrogen atoms) leads to a consistent interpretation of the spectra. KW - Ionic liquids KW - NEXAFS KW - DFT spectrum simulations PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367223 DO - https://doi.org/10.1039/c5cp07434g SN - 1463-9076 SN - 1463-9084 VL - 18 IS - 12 SP - 8654 EP - 8661 PB - Royal Society of Chemistry CY - Cambridge, UK AN - OPUS4-36722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Wolfgang T1 - Advanced surface chemical analysis of plasma modified polymers and plasma-polymers N2 - A comprehensive characterization of plasma modified polymer surfaces or plasma-polymerized thin films needs access to parameters as - concentration of saturated/unsaturated carbon species (e.g. aromaticity) or other double bonds as C=N or C=O, - branching, and - losses of crystallinty or other degrees of structural order. Furthermore the complex ageing phenomena of plasma modified polymers/plasma-polymers and the measurement of an in-depth distribution of chemical species are challenges for the analyst. The talk will display selected examples where such challenges have been met by using advanced methods of surface chemical analyses as Photoelectron Spectroscopy with variable excitation energy (“SyncXPS”), X-ray Absorption Spectroscopy (NEXAFS) at C, N and O K-edges and Time-of-Flight Secondary Mass Spectroscopy (ToF-SIMS) combined with Principal Component analysis (PCA). T2 - IAP workshop – IAP 2016 "Organic surface modifications by plasmas and plasma-polymers" CY - Nancy, France DA - 08.06.2016 KW - XPS KW - NEXAFS KW - SIMS KW - Plasmapolymer PY - 2016 AN - OPUS4-36725 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Peplinski, Burkhard A1 - Adamczyk, Burkart A1 - Meyer, Christian A1 - Krüger, Oliver A1 - Scharf, Holger A1 - Reinsch, Stefan A1 - Ostermann, Markus A1 - Nofz, Marianne A1 - Jäger, Christian A1 - Adam, Christian A1 - Emmerling, Franziska T1 - Nanocrystalline and stacking-disordered beta-cristobalite AlPO4 stabilized at room temperature: synthesis and X-ray powder diffraction data N2 - X-ray powder diffraction (XRD) patterns of the high-temperature (HT) cristobalite form of SiO2 and its isoelectronic AlPO4 analogue are essentially influenced by the dynamic disorder of these crystal structures. The nature of this disorder and of the phase transition between the α- and β-form has been the subject of intensive research during the last four decades [1]. By 1989 it became possible to stabilize the HT-form of cristobalite SiO2 at room temperature in laboratory and engineering ceramic industries by applying solid solution forming techniques [2]. However, for the HT-form of cristobalite AlPO4 nothing similar has been known until 2014 when it was discovered that nanocrystalline and stacking-disordered β-cristobalite AlPO4 is the major component of the fly ash of a large incineration facility operated by the waste water treatment authorities of Frankfurt/M. [3]. Previous comprehensive investigations of this fly ash failed to interpret its complex XRD pattern – presumably mainly due to the lack of a matching experimental digital pattern in the Powder Diffraction Database. The present paper reports on a synthesis route that facilitates the crystallization of nanocrystalline and stacking-disordered β-cristobalite AlPO4 that is free of crystalline impurity phases and long-term stable at ambient. Its room temperature XRD pattern is presented with parameters traced back to certified reference materials. [1] Yuan F. and Huang L., Phys. Rev, B, 2012, 85, 134114. [2] Perrotta J.A., Grubbs D.K., Martin E.S., Dando N.R., McKinstry H.A. and Huang C.-Y., J. Am. Ceram. Soc., 1989, 72, 441. [3] Peplinski B., Adam C., Adamczyk B., Müller R., Michaelis M., Krahl Th. and Emmerling F., Powder Diffraction Journal, 2015, 30, 2, Supp. 1, S31. T2 - 15. European Powder Diffraction Conference (EPDIC15) CY - Bari, Italy DA - 12. June 2016 KW - Stabilization of HT-structures at room temperature KW - β-cristobalite structure type KW - Databases PY - 2016 AN - OPUS4-36727 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hübert, Thomas A1 - Tiebe, Carlo A1 - Detjens, Marc A1 - Majewski, J. T1 - On-site calibration system for trace humidity sensors N2 - A portable device for calibration of trace humidity sensors and an adopted calibration procedure have been developed. The calibration device is based on humidity generation by permeating water through polymeric membrane tubes. Water vapour transmission rates for various polymers were experimentally determined in order to select the most suitable polymeric material. The developed trace humidity generator consists of a gas-flow polymeric hose immersed in a water reservoir thermostated by a sensorcontrolled heater. Mole fractions of water vapour between 1 µmol/ molˉ¹ and 350 µmol/molˉ¹ (equivalent to frost-point temperatures from -76 °C to -31 °C) were generated by varying either the operating temperature or gas flow. The operating temperature can be varied from 20 °C to 60 °C and kept stable within 0.1 K. Uncertainty analysis indicated that the trace humidity generator produces gas flows of constant humidity amounts with a relative expanded uncertainty less than 3.4% (k = 2) of the generated value. KW - Polymeric tubes KW - Measurements KW - Trace Humidity KW - Sensor calibration KW - Water vapour permeation PY - 2016 DO - https://doi.org/10.1016/j.measurement.2016.05.013 SN - 0263-2241 VL - 91 IS - 9 SP - 251 EP - 257 PB - Elsevier Ltd. AN - OPUS4-36762 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fischer, Franziska A1 - Heidrich, Adrian A1 - Greiser, Sebastian A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Polymorphism of mechanochemically synthesized Cocrystals: an in situ study N2 - In situ investigations using PXRD coupled with Raman spectroscopy permit the evaluation of the formation pathways of milling reactions. The liquid-assisted grinding cocrystallisation of theophylline with benzamide leading to polymorphic compounds was investigated. The dipole moment of the solvent used in the synthesis determines the structure of the polymorphic product. A detailed investigation allows determining the kinetically and thermodynamically favored product. In situ observations of the formation pathway during the grinding process of both polymorphs show that the thermodynamically favored cocrystal is formed in a two-step mechanism with the kinetic cocrystal as intermediate. The evaluation of the mechanochemical formation pathways reveals the importance of in situ investigations for an in depth understanding of mechanochemical synthesis mechanisms. Our study demonstrates that the choice of the solvent in the LAG synthesis is decisive for the controlled formation of a desired polymorphic final product. T2 - CGOM/ BACG 47th Annual British Association of Crystal Growth Conference CY - Leeds, UK DA - 28.06.2016 KW - Cocrystal KW - Mechanochemistry KW - Milling PY - 2016 AN - OPUS4-36764 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bierstedt, Andreas A1 - Riedel, Jens T1 - High-repetition rate laser ablation coupled to dielectric barrier discharge postionization for ambient mass spectrometry N2 - Most ambient sample introduction and ionization techniques for native mass spectrometry are highly selective for polar agents. To achieve a more general sensitivity for a wider range of target analytes, a novel laser ablation dielectric barrier discharge (LA DBD) ionization scheme was developed. The Approach employs a two-step mechanism with subsequent sample desorption and post-ionization. Effective Ablation was achieved by the second harmonic output (λ = 532 nm) of a diode pumped Nd:YVO₄ laser operating at a high-repetition rate of several kHz and pulse energies below 100 μJ. The ejected analytecontaining aerosol was consecutively vaporized and ionized in the afterglow of a DBD plasma jet. Depending on their proton affinity the superexcited Helium species in this afterglow produced analyte ions as protonated and ammoniated species, as well as radical cations. The optimization procedure could corroborate underlying conceptual consideration on the ablation, desorption and ionization mechanisms. A successful detection of a variety of target molecules could be shown from the pharmaceutical ibuprofen, urea, the amino acids L-arginine, L-lysine, the polymer polyethylene glycol, the organometallic compound ferrocene and the technical mixture wild mint oil. For a reliable evaluation of the introduced detection procedure spectra from the naturally abundant alkaloid capsaicin in dried capsicum fruits were recorded. KW - Laser ablation KW - High-repetition rate laser KW - Dielectric barrier discharge KW - Ambient mass spectrometry PY - 2016 DO - https://doi.org/10.1016/j.ymeth.2016.02.002 SN - 1046-2023 IS - 104 SP - 3 EP - 10 PB - Elsevier CY - Oxford AN - OPUS4-36730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maierhofer, Christiane A1 - Rothbart, Nick A1 - Hohlstein, F. A1 - Koch, J. A1 - Kryukov, I. A1 - Mahler, G. A1 - Stotter, B. A1 - Walle, G. A1 - Oswald-Tranta, B. A1 - Sengebusch, M. A1 - Goldammer, M. T1 - A round robin test on flash thermography N2 - A round robin test on flash thermography was organized within the scope of a standardization research project. This test gives information on reliability, comparability and efficiency of different testing situations. Data recorded on metal and CFRP test specimens with flat bottom holes (FBH) were analysed by evaluating the detectability and by calculating the signal-to-noise ratio (SNR) of the defect signatures as a function of defect parameters. For the investigation of the influence of material properties on the spatial resolution as well as on penetration depth, test specimens made of steel and copper with crossed notches and a notch ramp were constructed and investigated. Here, the minimum resolvable notch distance and the maximum detectable depth of the ramp were analysed. T2 - 19th World Conference on Non-destructive Testing (WCNDT) CY - Munich, Germany DA - 13.06.2016 KW - Active thermography KW - Flash excitation KW - Round robin test KW - Standardisation PY - 2016 AN - OPUS4-36684 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rothbart, Nick A1 - Maierhofer, Christiane A1 - Goldammer, M. A1 - Hohlstein, F. A1 - Koch, J. A1 - Kryukov, I. A1 - Mahler, G. A1 - Stotter, B. A1 - Walle, G. A1 - Oswald-Tranta, B. A1 - Sengebusch, M. T1 - A round robin test on flash thermography N2 - A round robin test on flash thermography was organized within the scope of a standardization research project. This test gives information on reliability, comparability and efficiency of different testing situations. Data recorded on metal and CFRP test specimens with flat bottom holes (FBH) were analysed by evaluating the detectability and by calculating the signal-to-noise ratio (SNR) of the defect signatures as a function of defect parameters. For the investigation of the influence of material properties on the spatial resolution as well as on penetration depth, test specimens made of steel and copper with crossed notches and a notch ramp were constructed and investigated. Here, the minimum resolvable notch distance and the maximum detectable depth of the ramp were analysed. T2 - 19th World Conference on Non-destructive Testing (WCNDT) CY - Munich, Germany DA - 13.06.2016 KW - Active thermography KW - Flash excitation KW - Round robin test KW - Standardisation PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366853 SN - 978-3-940283-78-8 VL - BB 158 SP - We.3.D.4., 1 EP - 8 PB - DGZfP CY - Berlin AN - OPUS4-36685 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Daschewski, Maxim A1 - Bartusch, Jürgen A1 - Schadow, Florian A1 - Dohse, Elmar A1 - Kreutzbruck, Marc A1 - Weise, Matthias A1 - Beck, Uwe T1 - Novel air-coupled ultrasonic transducer combining the thermoacoustic with the piezoelectric effect N2 - In recent years, there has been an increasing industrial demand for one-sided inspection of various structures by means of air-coupled ultrasonic technique. Lightweight structures based on carbon-fibre-reinforced polymers may have very complex shapes, making air-coupled transmission difficult or even impossible. The inspection of concrete structures is another example where one-sided inspection is required. To address these challenges a new type of transducer for air-coupled pulse-echo inspection was developed, which unites two principles: thermoacoustic emission and piezoelectric reception. The thermoacoustic emitter is a titanium electrode with a thickness of several tens of nanometer. This electrode was deposited onto charged cellular polypropylene, which serves as a piezoelectric receiver. The thermoacoustic transmission is based on a transformation of the thermal energy of an electrically heated electrode into the acoustic energy of an ultrasonic wave. Thermoacoustic emitters provide resonance-free behaviour and thus extremely broadband pulses. Charged cellular polypropylene is piezoelectric due to the polarization of its cells and it is well matched to air, with a Young modulus in the order of magnitude of MPa. In this contribution we present some pulse-echo measurements with the first prototypes of the combined thermoacoustic-piezoelectric transducer. T2 - World Conference of Non-Destructive Testing CY - Munich, Germany DA - 13.6.2016 KW - Thermoacoustic KW - Piezoelectric KW - Ultrasonic transducer KW - Ferroelectret PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367151 VL - 158 SP - Mo.1.F.4, 1 EP - 6 AN - OPUS4-36715 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Daschewski, Maxim A1 - Bartusch, Jürgen A1 - Schadow, Florian A1 - Dohse, Elmar A1 - Kreutzbruck, Marc A1 - Weise, Matthias A1 - Beck, Uwe T1 - Novel air-coupled ultrasonic transducer combining the thermoacoustic with the piezoelectric effect N2 - In recent years, there has been an increasing industrial demand for one-sided inspection of various structures by means of air-coupled ultrasonic technique. Lightweight structures based on carbon-fibre-reinforced polymers may have very complex shapes, making air-coupled transmission difficult or even impossible. The inspection of concrete structures is another example where one-sided inspection is required. To address these challenges a new type of transducer for air-coupled pulse-echo inspection was developed, which unites two principles: thermoacoustic emission and piezoelectric reception. The thermoacoustic emitter is a titanium electrode with a thickness of several tens of nanometer. This electrode was deposited onto charged cellular polypropylene, which serves as a piezoelectric receiver. The thermoacoustic transmission is based on a transformation of the thermal energy of an electrically heated electrode into the acoustic energy of an ultrasonic wave. Thermoacoustic emitters provide resonance-free behaviour and thus extremely broadband pulses. Charged cellular polypropylene is piezoelectric due to the polarization of its cells and it is well matched to air, with a Young modulus in the order of magnitude of MPa. In this contribution we present some pulse-echo measurements with the first prototypes of the combined thermoacoustic-piezoelectric transducer. T2 - World Conference of Non-Destructive Testing CY - Munich, Germany DA - 13.6.2016 KW - Ferroelectret KW - Thermoacoustic KW - Piezoelectric KW - Ultrasonic transducer PY - 2016 AN - OPUS4-36716 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübert, Thomas T1 - Gas sensors for technical safety and process control N2 - The presentation gives an overview on sensor principles and materials. Examples for sensor application in technical safety and process control were presented and the contribution of BAM in sensor testing, validation and standadization are discussed. T2 - Vortrag in der Abteilung Physik des ITS (Institute Technology Surabaya) CY - Surabaya, Indonesia DA - 29-08-2016 KW - Gas sensor KW - Safety KW - Process control PY - 2016 AN - OPUS4-37358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Köppe, Enrico A1 - Schukar, Vivien A1 - Hofmann, Detlef A1 - Westphal, Anja A1 - Sahre, Mario A1 - Gong, Xin A1 - Basedau, Frank A1 - Bartholmai, Matthias A1 - Beck, Uwe T1 - Magnetic field detection with an advanced FBG-based sensor device N2 - A high-performance fiber Bragg grating-based (FBG) sensor device for the detection of small magnetic fields has been developed. Based on a smart multilayer coating exposed over the physical length of the FBG, magnetic fields exhibited by rotating machine parts, power generators or current cable can easily be detected, analysed and evaluated. Consequently, this innovative, in-process and non-contact inspection method leads to an increase in quality and reliability of high-performing machine parts, devices and cables. The basic physical concept is based on a magnetostrictive multilayer coating system that strains the high-resolution FBG element. Subsequently, a fixed relationship between induced magnetic field and wavelength change of the FBG element forms the characteristic sensitivity curve. Intensive tests regarding the characterisation of the magnetic field FBG sensor have been carried out and its performance has been evaluated. T2 - EuroSensors XXX 2016 CY - Budapest, Hungary DA - 04.09.2016 KW - Strain KW - Fiber Bragg grating KW - Magnetostriction KW - Magnetic field PY - 2016 AN - OPUS4-37364 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bertin, Annabelle A1 - Asadujjaman, Asad A1 - Rurack, Knut T1 - Endowing nanoparticles with orthogonal functionalities via core / shell / shell architecture N2 - Dual orthogonal functionality in a single material is highly desirable in many fields such as bio-imaging, sensing, coating or diagnostic and therapy. However, combining two different functionalities in a precise and controlled way is still a challenging task. Here we present how simply dual functional hybrid nanoparticles consisting of a silica core with a fluorescent and a thermoresponsive polymeric layers can be prepared. As a first step of this work, silica core particles were coated by a fluorescent layer using surface-initiated reversible addition-fragmentation chain transfer polymerization. Afterwards, the fluorescent silica nanoparticles were completely enclosed in a switchable protective coating made of thermoresponsive poly(N-isopropylacrylamide). The thermoresponsive poly(N-isopropylacrylamide) changes its properties with varying the surroundings temperature and this behavior is reversible and controllable. To the best of our knowledge these types of hybrid dual functional core-shell-shell nanoparticles have not yet been prepared, despite the prospect of many potential applications. T2 - World Congress on Living Polymerizations and Polymers - LPP16 CY - Budapest, Hungary DA - 29.05.2016 KW - Fluorescent and thermoresponsive nanoparticles KW - Core KW - Shell KW - Shell nanoparticles PY - 2016 AN - OPUS4-37367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Nanoparticles and films characterization: Electron microscopy and related techniques N2 - Scanning Electron Microscopy (SEM) represents the mostly widespread method available in analytical laboratories dedicated to the characterization of physical properties such as morphology of various solid materials from ‘micro-’ down to the nanometre scale. The use of secondary electrons excited by a sharply, nm-focussed primary electron beam enables at any modern SEM to image objects with high in-depth and lateral sensitivity, i.e. with high spatial resolution. Hence, e. g. nanoparticles (NPs) are able to be easily characterized with respect to their individual size and shape, but also to the morphology of their surface. By preparing the nano-objects on thin membranes as electron transparent samples it is possible to perform electron microscopy in the transmission mode (TEM and TSEM). The corresponding transmission (i.e. mass-thickness) contrast reveals in-depth information, but is also well suited for dimensional measurements in the 2D projection image. Both the surface sensitive mode and the transmission one are meanwhile available at any modern SEM. If an X-ray spectrometer is attached to an electron microscope, it is possible to analyse the characteristic X-rays induced by electron bombardment. Most electron microscopes have attached an energy dispersive X-ray spectrometer (EDX) so that EDX elemental maps can be carried out. Recent technological developments of high throughput EDS detectors and their advantages regarding high-resolution X-ray analysis down to the nm range are reviewed. High-resolution micrographs (SEM, TSEM, TEM) and corresponding X-ray elemental maps on various representative nanoparticles, but also layered samples prepared in cross-section, will be presented and discussed. The importance of selecting the best suited analysis conditions will be highlighted. Also other, often challenging, topics such as sample preparation and image data processing will be critically addressed by practical examples. Further analytical techniques able to be employed at an electron microscope, like cathodoluminescence (CL) or micro-X-ray fluorescence (µXRF) will be briefly surveyed. T2 - Nanoscience Meets Metrology - Synthesis, Characterization, Testing and Applications of Validated Nanoparticles - International Summer School CY - Turin, Italy DA - 04.09.2016 KW - Nanoparticles KW - Electron microscopy KW - High-resolution KW - Thin films KW - X-ray spectroscopy PY - 2016 UR - http://www.setnanometro.eu/events/ AN - OPUS4-37325 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Färber, C. A1 - Titschack, J. A1 - Schönberg, Chr. H. L. A1 - Ehrig, Karsten A1 - Boos, K. A1 - Illerhaus, Bernhard A1 - Asgaard, U. A1 - Bromley, R. G. A1 - Freiwald, A. A1 - Wisshak, M. ED - Bahn, M. ED - Fennel, K. ED - Kesselmeier, J. ED - Naqvi, S. W. A. T1 - Long-term macrobioerosion in the Mediterranean Sea assessed by micro-computed tomography N2 - Biological erosion is a key process for the recycling of carbonate and the formation of calcareous sediments in the oceans. Experimental studies showed that bioerosion is subject to distinct temporal variability, but previous long-term studies were restricted to tropical waters. Here, we present results from a 14-year bioerosion experiment that was carried out along the rocky limestone coast of the island of Rhodes, Greece, in the Eastern Mediterranean Sea, in order to monitor the pace at which bioerosion affects carbonate substrate and the sequence of colonisation by bioeroding organisms. Internal macrobioerosion was visualised and quantified by micro-computed tomography and computer-algorithm-based segmentation procedures. Analysis of internal macrobioerosion traces revealed a dominance of bioeroding sponges producing eight types of characteristic Entobia cavity networks, which were matched to five different clionaid sponges by spicule identification in extracted tissue. The morphology of the entobians strongly varied depending on the species of the producing sponge, its ontogenetic stage, available space, and competition by other bioeroders. An early community developed during the first 5 years of exposure with initially very low macrobioerosion rates and was followed by an intermediate stage when sponges formed large and more diverse entobians and bioerosion rates in-creased. After 14 years, 30 % of the block volumes were occupied by boring sponges, yielding maximum bioerosion rates of 900 g m. KW - Bioerosion KW - Computed tomography KW - Carbonate substrate PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-372709 UR - http://www.biogeosciences.net/13/3461/2016/bg-13-3461-2016.pdf DO - https://doi.org/10.5194/bg-13-3461-2016 VL - 13 IS - 11 SP - 3461 EP - 3474 PB - Copernicus Publications CY - Göttingen AN - OPUS4-37270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schäferling, Michael A1 - Deguchi, T. A1 - Christ, S. A1 - Peltomaa, R. A1 - Prabhakar, N. A1 - Rosenholm, J. A1 - Arppe, Riika A1 - Soukka, T. A1 - Näreoja, T. T1 - Nanoprobes for sensing and imaging of intracellular pH based on polyethyleneimide-coated photon upconversion nanoparticles conjugated to a pH sensitive rhodamine dye N2 - Lanthanide-doped photon upconversion nanoparticles (UCNPs) exhibit many advantages compared to Stokes-shifted luminescent probes (organic dyes, quantum dots). Due to the upconversion process, the limitations of photobleaching, autofluorescence and low penetration depths in tissue shown by classical fluorescent probes are avoided. This makes UCNPs particularly useful for applications in complex biological samples. Sensing of intracellular pH is of particular interest in biomedical research since structure and function of biomolecules strongly depend on the concentration of protons in their environment. T2 - UPCON 2016 CY - Wroclaw, Poland DA - 23.05.2016 KW - upconversion KW - nanoprobes KW - chemical sensing PY - 2016 AN - OPUS4-37282 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schäferling, Michael A1 - Deguchi, T. A1 - Christ, S. A1 - Peltomaa, R. A1 - Prabhakar, N. A1 - Rosenholm, J. A1 - Arppe, Riika A1 - Soukka, T. A1 - Näreoja, T. T1 - Sensing and Imaging of Intracellular pH Using Polyethyleneimine-coated Photon Upconversion Based Nanoprobes N2 - Lanthanide-doped photon upconversion nanoparticles (UCNPs) exhibit many advantages compared to conventional Stokes-shifted luminescent probes such as organic dyes and quantum dots. Due to the upconversion (UC) process, which describes the conversion of NIR light into shorter wavelength radiation, the limitations of photobleaching, autofluorescence and low penetration depths in tissue shown by classical fluorescent probes absorbing in the UV/vis range are avoided. This makes UCNPs particularly useful for applications in complex samples occurring in bioanalysis, biomedicine and imaging. Sensing of intracellular pH is of particular interest in biomedical research since structure and function of biomolecules strongly depend on the concentration of protons in their environment. We described previously a UCNP nanosensor for pH based on a resonance energy transfer from hexagonal nanocrystals of NaYF4: Yb3+,Er3+ to a pH-sensitive fluorophore (pHrodoTM Red).[1] The nanocrystals were coated with a thin shell of aminosilane with several nanometer layer thickness for coupling of the pH indicator. In this contribution we present a new generation of UC nanoprobes that are coated with a layer of highly branched polyethylenimine (PEI). The PEI coating enables a higher coupling of indicator molecules on the particle surface, better signal to reference ratios in ratiometric readout and an improved cellular uptake compared to the aminosilane coated particles due to a more positive zeta potential. Again, pHrodoTM Red is used as pH indicator, sensitized by the 550 nm emission of the UCNPs. The nanoprobes are calibrated by ratiometric dual wavelength readout at 550 nm (reference signal) and 590 nm (sensor signal) and visualized using a scanning confocal fluorescence microscope with 980 nm excitation wavelength. We studied the cellular uptake efficacy of the nanoprobes and determined to which type of compartment, lysosomes, endosomes or cytosol, the probes are targeted to by measuring the pH of their microenvironment. An in situ control was performed in live cells by a treatment with nigericin, whereby the pH of all intracellular compartments is set at extracellular level. Our results suggest that the PEI coating facilitated endosomal escape of the nanoprobes. T2 - Europtrode XIII CY - Graz, Austria DA - 20.03.2016 KW - upconversion KW - chemical sensing KW - nanoprobes PY - 2016 AN - OPUS4-37283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bierstedt, Andreas A1 - Riedel, Jens T1 - Airborne laser-spark for ambient desorption/ionisation N2 - A novel direct sampling ionisation scheme for ambient mass spectrometry is presented. Desorption and ionisation are achieved by a quasi-continuous laser induced plasma in air. Since there are no solid or liquid electrodes involved the ion source does not suffer from chemical interferences or fatigue originating from erosive burning or from electrode consumption. The overall plasma maintains electro-neutrality, minimising charge effects and accompanying long term drift of the charged particles trajectories. In the airborne plasma approach the ambient air not only serves as the plasma medium but at the same time also slows down the nascent ions via collisional cooling. Ionisation of the analyte molecules does not occur in the plasma itself but is induced by interaction with nascent ionic fragments, electrons and/or far ultraviolet photons in the plasma vicinity. At each individual air-spark an audible shockwave is formed, providing new reactive species, which expands concentrically and, thus, prevents direct contact of the analyte with the hot region inside the plasma itself. As a consequence the interaction volume between plasma and analyte does not exceed the threshold temperature for thermal dissociation or fragmentation. Experimentally this indirect ionisation scheme is demonstrated to be widely unspecific to the chemical nature of the analyte and to hardly result in any fragmentation of the studied molecules. A vast ensemble of different test analytes including polar and non-polar hydrocarbons, sugars, low mass active ingredients of pharmaceuticals as well as natural biomolecules in food samples directly out of their complex matrices could be shown to yield easily accessible yet meaningful spectra. Since the plasma medium is humid air, the chemical reaction mechanism of the ionisation is likely to be similar to other ambient ionisation techniques. N2 - Wir stellen hier eine neue Ionisationsmethode für die Umgebungsionisation (ambient ionisation) vor. Sowohl die Desorption als auch die Ionisation erfolgen hierbei durch ein laserbetriebenes Luftplasma. Die Abwesenheit fester oder flüssiger Elektroden hat zur Folge, dass die Methode weder unter chemischen Interferenzen noch unter Verschleiß durch Korrosionsbrand oder abgetragenes Elektrodenmaterial leidet. Insgesamt betrachtet herrscht in dem Plasma Elektroneutralität, wodurch Aufladungseffekte minimiert werden, die andernfalls zu einer langfristigenÄderung der Flugbahnen von Ionen während der Experimente führen kann. In dem Ansatz eine freischwebende Luftentladung bei Atmosphärendruck zu verwenden agiert die Luft nicht nur als Plasmamedium sondert dient zusätzlich als Badgas für die stoßinduzierte Kühlung der entstehenden Ionen. Die Ionisierung der Analytmoleküle erfolgt nicht unmittelbar im Plasma sondern in dessen direkter Umgebung durch Wechselwirkung mit freigesetzten ionischen Luftspezies, freien Elektronen oder Photonen im kurzwelligen ultravioletten Bereich. Jede Laserentladung erzeugt eine hörbare Stoßwelle, in welcher neu produzierte reaktive Spezies freigesetzt werden, welche sich konzentrisch ausbreiten, so dass eine Diffusion der Analytmoleküle ins heiße Innere des Plasmas verhindert wird. Daraus folgt, dass im Interaktionsvolumen zwischen Plasma und Analyt der Temperaturgrenzwert für eine thermische Dissoziation oder Fragmentierung der Moleküle nicht überschritten wird. Experimentell konnte belegt werden, dass das vorgestellte Ionisierungsschema sehr unselektiv bezüglich der chemischen Analytklasse ist und kaum Fragmentierungsprodukte beobachtet werden können. Messungen einer breitgefächerten Auswahl unterschiedlicher Testsubstanzen, wie beispielsweise polarer und unpolarer Kohlenwasserstoffe, Zuckern, niedermolekularer pharmazeutischer Wirkstoffe, sowie natürlicher Biomoleküle in Lebensmittelproben unmittelbar aus ihren komplexen Matrizes, führten zu aussagekräftigen Massenspektren. Zumal das Lasermedium feuchte Luft ist, scheint der Reaktionsmechanismus dem anderer Atmosphärendruckionisierungsmethoden zuähneln. KW - Laser-spark KW - Laser-induced plasma KW - DPSS laser KW - High repetition rate KW - Ambient mass spectrometry KW - Time-of-flight mass spectrometry KW - Ionisation PY - 2016 DO - https://doi.org/10.1255/ejms.1417 SN - 1469-0667 VL - 22 IS - 3 SP - 105 EP - 114 PB - IM Publications LLP CY - Chichester, UK AN - OPUS4-37286 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bertin, Annabelle A1 - Asadujjaman, Asad A1 - Rurack, Knut T1 - Endowing nanoparticles with orthogonal functionalities via core / shell / shell architecture N2 - Dual orthogonal functionality in a single material is highly desirable in many fields such as bio-imaging, sensing, coating or diagnostic and therapy. However, combining two different functionalities in a precise and controlled way is still a challenging task. Here we present how simply dual functional hybrid nanoparticles consisting of a silica core with a fluorescent and a thermoresponsive polymeric layers can be prepared. As a first step of this work, silica core particles were coated by a fluorescent layer using surface-initiated reversible addition-fragmentation chain transfer polymerization. Afterwards, the fluorescent silica nanoparticles were completely enclosed in a switchable protective coating made of thermoresponsive poly(N-isopropylacrylamide). The thermoresponsive poly(N-isopropylacrylamide) changes its properties with varying the surroundings temperature and this behavior is reversible and controllable. To the best of our knowledge these types of hybrid dual functional core-shell-shell nanoparticles have not yet been prepared, despite the prospect of many potential applications. T2 - 251st American Chemical Society National Meeting CY - San Diego, USA DA - 13.03.2016 KW - Fluorescent and thermoresponsive nanoparticles KW - Core / shell / shell / nanoparticles PY - 2016 AN - OPUS4-37370 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rackwitz, J. A1 - Kopyra, J. A1 - Dabkowska, I. A1 - Ebel, K. A1 - Rankovic, M. A1 - Milosavljevic, A. R. A1 - Bald, Ilko T1 - Sensitizing DNAtowards low-energy electrons with 2-fluoroadenine N2 - 2-Fluoroadenine (2FA) is a therapeutic agent, which is suggested for application in cancer radiotherapy. The molecular mechanism of DNA radiation damage can be ascribed to a significant extent to the action of low-energy (<20 eV) electrons (LEEs), which damage DNA by dissociative electron attachment. LEE induced reactions in 2FA are characterized both isolated in the gas phase and in the condensed phase when it is incorporated into DNA. Information about negative ion resonances and anion-mediated fragmentation reactions is combined with an absolute quantification of DNA strand breaks in 2FA-containing oligonucleotides upon irradiation with LEEs. The incorporation of 2FA into DNA results in an enhanced strand breakage. The strand-break cross sections are clearly energy dependent, whereas the strand-break enhancements by 2FA at 5.5, 10, and 15 eV are very similar. Thus, 2FA can be considered an effective radiosensitizer operative at a wide range of electron energies. KW - Ab initio calculations KW - Dissociative electron attachment KW - DNA origami KW - DNA radiation damage KW - Fludarabine PY - 2016 UR - http://onlinelibrary.wiley.com/doi/10.1002/anie.201603464/full DO - https://doi.org/10.1002/anie.201603464 SN - 1433-7851 SN - 1521-3773 VL - 55 IS - 35 SP - 10248 EP - 10252 AN - OPUS4-37372 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pollakowski, B. A1 - Holzlechner, Gerald A1 - Lippitz, Andreas A1 - Beckhoff, B. A1 - Unger, Wolfgang T1 - Qualifying PDMS deposited on silicon wafer surfaces as calibration standard for organic matter by X-ray spectrometry and XPS N2 - Polydimethylsiloxane (PDMS)is one of the most appearing contamination of medical devices.Dedicated analysis of PDMS on surfaces necessary, but the lack of calibration samples provides a bottle neck. There is a demand for metrological tools ensuring traceable and reliable analysis of mass deposition and of the chemical species of contaminants. Photoelectron spectroscopy (PES) and reference-free GIXRF can be used to qualify bench top instrumentation. Comparison of PES data and GIXRF data enable the establishment of a traceability chain. T2 - EXRS 2016, European Conference on X - ray Spectrometry CY - Gothenburg, Sweden DA - 19.06.2016 KW - Silicone analysis KW - XPS KW - GIXRF PY - 2016 AN - OPUS4-37295 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sobol, Oded A1 - Holzlechner, Gerald A1 - Nolze, Gert A1 - Wirth, Thomas A1 - Eliezer, D. A1 - Böllinghaus, Thomas A1 - Unger, Wolfgang T1 - Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) imaging of deuterium assisted cracking in a 2205 duplex stainless steel microstructure N2 - In the present work, the influence of deuterium on the microstructure of a duplex stainless steel type EN 1.4462 has been characterized by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) supported by scanning electron microscopy (SEM), focused ion beam (FIB), electron back scattered diffraction(EBSD) and energy dispersive x-ray (EDX) investigations. Characterization has been carried out before and after electrochemical charging with deuterium which has been used as a tracer, due to its similar behavior to hydrogen in the steel microstructure. In a first approach, the distribution of the deuterium occurring at temperatures above 58 °C has been visualized. Further it turned out that sub-surface micro blisters are formed in the ferrite-austenite interface, followed by the formation of needle shaped plates and subsequent cracking at the ferrite surface. In the austenite phase, parallel cracking alongside twins and hexagonal close packed (martensitic) regions has been observed. In both phases and even in the apparent interface, cracking has been associated with high deuterium concentrations, as compared to the surrounding undamaged microstructure. Sub-surface blistering in the ferrite has to be attributed to the accumulation and recombination of deuterium at the ferrite-austenite interface underneath the respective ferrite grains and after fast diffusing through this phase. Generally, the present application of chemometric imaging and structural analyses allows characterization of hydrogen assisted degradation at a sub-micron lateral resolution. KW - ToF-SIMS KW - Hydrogen assisted cracking KW - Hydrogen embrittlement KW - SEM KW - FIB KW - EBSD PY - 2016 UR - http://www.sciencedirect.com/science/article/pii/S0921509316310334 DO - https://doi.org/10.1016/j.msea.2016.08.107 SN - 0921-5093 VL - 676 SP - 271 EP - 277 PB - Elsevier B.V. AN - OPUS4-37298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Broadband Dielectric Spectroscopy - Basics and Selected Applications N2 - The basics of broadband dielectric spectroscopy were introduced in detail. The analysis of the data was discussed. As application of broadband dielectric spectroscopy the alpha-relaxation (dynamic glass transition) and the chain dynamics of polymers were ilustrated. T2 - 9th International Conference on Broadband Dielectric Spectroscopy and its Applications CY - Pisa, Italy DA - 11.09.2016 KW - Broadband Dielectric Spectroscopy PY - 2016 AN - OPUS4-37386 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas A1 - Madkour, Sherif A1 - Yin, Huajie A1 - Szymoniak, Paulina T1 - Behavior of Ultra-Thin Films of Blends of Polystyrene/ Poly(vinyl methyl ether) by Nanosized Relaxation Spectroscopy N2 - In the course of miniaturizing modern technology down to the molecular scale, understanding the materials behavior has to be investigated and deviations from the bulk that might arises from confinement effects has to be understood. Here, a combination of nano-sized relaxation spectroscopies (Broadband dielectric spectroscopy (BDS) and Specific heat spectroscopy (SHS); employing AC nanochip calorimetry) were utilized to investigate the glassy dynamics of ultra-thin films of blends of Poly (vinyl methyl ether) (PVME) / Polystyrene (PS) 50:50 wt-%, which are miscible bulk (thicknesses: 8nm - 200nm, film thickness was controlled by ellipsometry, film topography by AFM). Both methods are sensitive to different probes; where SHS senses entropy fluctuations while BDS measures dipole fluctuations. For BDS measurements, a recently developed nano-structured electrode sample arrangement is employed; where ultra-thin films are spin-coated on an ultra-flat highly conductive silicon wafer, sandwiched between a wafer with nanostructured SiO2 nano-spacers with heights between 35 nm and 70 nm. The method was applied for film thicknesses up to 50 nm. For thicker films, the samples were prepared between crossed electrodes. It was proven that, for 50 nm films, both contact methods will lead to identical results. By measuring the dynamic Tg in dependence of the film thickness, SHS showed that the Tg of the whole film was strongly influenced by a nanometer-thick surface layer at the polymer/air interface due to a self-assembling process [1]. The dynamic Tg obtained from the SHS measurements decrease with decreasing film thickness, evidencing the importance of a mobile surface layer at the polymer/air interface for the glass transition of the whole film. Compared to the SHS results, the BDS measurements show a completely different behavior. At high temperatures, the temperature dependence of the relaxation times of the films follows that of bulk-like PS/PVME; obeying the VFT-law. With decreasing temperature, the temperature dependence deviates from the VFT to an Arrhenius law; where the apparent activation energy decreases with decreasing film thickness. This is the first example where confinement induced changes were observed by BDS for ultra-thin films. All results were analyzed in details in a comprehensive discussion. T2 - 9th International Conference on Broadband Dielectric Spectroscopy and its Applications CY - Pisa, Italy DA - 11.09.2016 KW - Ultra-Thin films KW - Broadband Dielectric Spectrscopy KW - Nanostructured Electrodes PY - 2016 AN - OPUS4-37387 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe ED - Baier, Jennifa ED - Sahre, Mario ED - Weise, Matthias ED - Dähne, L. ED - Lerche, K.-H. T1 - Plasma Compatibility of Particles for Functional PVD-coatings by ex-situ Injection - Stability of Particles under Plasma Conditions N2 - The validation of the plasma compatibility of particles is a prerequisite for their application in plasma dispersion layers. The goal is the realization of functional add-on features on surfaces, in films and coatings. Although intended applications primarily address nanoparticles, the compatibility tests were carried out at first with particles in the lower micrometer range in order to investigate material-, fluorescent marker- or surface-based degradation effects in a simple manner. Plasma compatibility implies at least the short-term acceptance of charged species, plasma-UV radiation, vacuum and elevated temperatures. Otherwise, effects on geometrical dimensions, chemical bonds, fluorescence efficiency and plastic-elastic properties are expected. The plasma compatibility of monodisperse fluorescent-labeled particles to microwave excitation was evaluated by means of microscopic and spectroscopic investigation methods (light, fluorescence, confocal, atomic force microscopy and FTIR). This study comprises particles of different materials (SiO2, PMMA, PS, MF) and sizes (from 50 nm to 10 μm). A special preparation technique ensures that smallest geometry changes of particles can be measured by atomic force microscopy. For the selected plasma conditions (P = 600 W, f = 2.46 GHz, d = 10 cm) and an exposure time of 10 minutes, the geometry of SiO2 particles (approx. 1.7 μm) remains nearly unchanged, whereas PS particles shrink in diameter by 6% and PMMA particles by 11%. For selected core-particles (SiO2, MF) with fluorescencemarked (rhodamine) shell-polyelectrolytes no remarkable plasma degradation of the fluorescence intensity was observed for the above mentioned plasma conditions, however a doubling of exposure time already results in a significant decrease in intensity. Two different injection systems have been studied for the particle injection into the plasma deposition process. One of the selected systems also proves process compatibility regarding the expected pressure differences upon injection. T2 - PARTEC 2016, International Congress on Particle Technology CY - Nürnberg, Germany DA - 19.04.2016 KW - plasma dispersion layers KW - functional PVD coatings KW - particle injection PY - 2016 SN - 978-3-18-092283-6 SN - 0083-5560 SP - 6. Applications of Particle Technology/6.11_Beck_Uwe PB - VDI Wissensforum GmbH CY - Düsseldorf AN - OPUS4-37265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Moser, Marko T1 - Spectroscopic Quantification of Thiol Groups and Ligands on Nanomaterials N2 - Thiols have a high binding affinity to noble metals and semiconductor (SC) materials. Thiol ligands enable size control and tuning of the surface during the synthesis of nanoparticles (NP), significantly influence their physico-chemical and optical properties, and allow for their bioconjugation via further functional groups. Thus, simple, inexpensive, robust, and fast methods for the quantification of thiol groups and the characterization of thiol-modified or - stabilized nanomaterials including polymers are of considerable importance. T2 - Innovation Forum Senftenberg 2016 CY - Senftenberg, Germany DA - 01.06.2016 KW - Thiols KW - Ellman KW - Aldrithiol PY - 2016 AN - OPUS4-37243 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Moser, Marko T1 - Quantification of PEG-Maleimide Ligands and Coupling Efficiencies on Nanoparticles with Ellman’s Reagent N2 - Emissive nanoparticles (NP) are of ever increasing importance in nanotechnology, optical industries, and life sciences. Applicationrelevant properties determining particle performance and biocompatibility depend mainly on surface functional groups or ligands. Coating with polyethylene glycol (PEG) ligands enhances hydrophilicity and biocompatibility of nanomaterials, and enables subsequent binding of biomolecules. Hence, PEGylated particles must be carefully engineered and monitored with simple and fast methods. T2 - 9th Meeting of Engineering of Functional Interfaces CY - Wildau, Germany DA - 03.07.2016 KW - PEG-Maleimide KW - Ellman PY - 2016 AN - OPUS4-37244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Moser, Marko A1 - Behnke, Thomas A1 - Schneider, Ralf A1 - Resch-Genger, Ute T1 - Spectroscopic Quantification of Thiol Groups and Ligands on Nanomaterials N2 - Thiols have a high binding affinity to noble metals and semiconductor (SC) materials. Thiol ligands enable size control and tuning of the surface during the synthesis of nanoparticles (NP), significantly influence their physico-chemical and optical properties, and allow for their bioconjugation via further functional groups. Thus, simple, inexpensive, robust, and fast methods for the quantification of thiol groups and the characterization of thiol-modified or - stabilized nanomaterials including polymers are of considerable importance. T2 - Innovation Forum Senftenberg 2016 CY - Senftenberg, Germany DA - 01.06.2016 KW - Ellman KW - Aldrithiol KW - Thiols PY - 2016 AN - OPUS4-37245 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Moser, Marko A1 - Behnke, Thomas A1 - Resch-Genger, Ute T1 - Quantification of PEG-Maleimide Ligands and Coupling Efficiencies on Nanoparticles with Ellman’s Reagent N2 - Emissive nanoparticles (NP) are of ever increasing importance in nanotechnology, optical industries, and life sciences. Applicationrelevant properties determining particle performance and biocompatibility depend mainly on surface functional groups or ligands. Coating with polyethylene glycol (PEG) ligands enhances hydrophilicity and biocompatibility of nanomaterials, and enables subsequent binding of biomolecules. Hence, PEGylated particles must be carefully engineered and monitored with simple and fast methods. T2 - 9th Meeting of Engineering of Functional Interfaces CY - Wildau, Germany DA - 03.07.2016 KW - PEG-Maleimide KW - Ellman PY - 2016 AN - OPUS4-37247 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kuchenbecker, Petra A1 - Güther, Wolfgang A1 - Lindemann, Franziska A1 - Höhne, Patrick A1 - Neumann, Christian A1 - Rabe, Torsten T1 - The Analytical centrifuge – an additional tool to optimize ceramic slurries for spray drying N2 - Spray drying is a widely used process step in ceramic technology to convert fine grained raw powders to free-flowing granules. Type and amount of the organic additives (dispersants, binders and plasticizers) define viscosity and stability of the slurry, the granulate structure and the compaction behaviour. Alumina and Zirconia powders were characterized with regard to particle size, shape and specific surface area (BET). Zeta-potential measurements by Stabino® were used to investigate the effect of different dispersants on slurry stability. Unfortunately, this method is restricted to suspensions with less than about 30% by weight of solid content. The multi-sample analytical centrifuge LUMiSizer® overcomes this problem. This device enables analysis of the separation behaviour of suspensions over a wide range of solid content. On the basis of position and time resolved photometric detection of transmitted light, it is possible to determine the instability index, the sedimentation velocity, and the sediment height in dependence of type and amount of organic additives at various centrifugal accelerations. Additional information is obtained from the shape of the transmission profiles. Based on LUMiSizer® measurements, suitable additive concentrations were derived. Thereby, the number of investigations by viscometry and spray drying experiments can be significantly reduced. Finally, it was possible to produce alumina, zirconia and ZTA aqueous slurries with up to 80 weight-% of solid. The optimized suspensions were successfully spray dried and the resulted granules show good compaction behaviour. T2 - Jahrestagung der Deutschen Keramischen Gesellschaft und Symposium Hochleistungskeramik CY - Freiberg, Germany DA - 07.03.2016 KW - Analytical centrifuge KW - Ceramic suspension KW - Slurry KW - Spray drying KW - Granules PY - 2016 AN - OPUS4-36130 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Emmerling, Franziska ED - de Oliveira Guilherme Buzanich, Ana ED - Strange, R. W. T1 - Time- and spatial-resolved XAFS spectroscopy in a single shot: new analytical possibilities for in situ material characterization N2 - A new concept that comprises both time- and lateral-resolved X-ray absorption fine-structure information simultaneously in a single shot is presented. This uncomplicated set-up was tested at the BAMline at BESSY-II (Berlin, Germany). The primary broadband beam was generated by a double multilayer monochromator. The transmitted beam through the sample is diffracted by a convexly bent Si (111) crystal, producing a divergent beam. This, in turn, is collected by either an energy-sensitive area detector, the so-called color X-ray camera, or by an area-sensitive detector based on a CCD camera, in θ–2θ geometry. The first tests were performed with thin metal foils and some iron oxide mixtures. A time resolution of lower than 1 s together with a spatial resolution in one dimension of at least 50 mm is achieved. KW - Single-shot XAFS KW - Time resolution PY - 2016 UR - http://scripts.iucr.org/cgi-bin/paper?S1600577516003969 DO - https://doi.org/10.1107/S1600577516003969 SN - 1600-5775 VL - 23 SP - 769 EP - 776 PB - International Union of Crystallography CY - Liverpool, UK AN - OPUS4-35903 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wilke, Manuel A1 - Batzdorf, Lisa A1 - Fischer, Franziska A1 - Rademann, Klaus A1 - Emmerling, Franziska T1 - Cadmium phenylphosphonates: preparation, characterisation and in situ investigation N2 - The successful mechanochemical syntheses of three cadmium phenylphosphonates indicates that mechanochemistry is ideally suited for synthesizing metal phosphonates. With this powerful synthesis tool it is possible to synthesize rapidly and efficiently both known and novel phosphonates. The Crystal structures of the two new compounds, and, were solved from PXRD data. They contain monodeprotonated phenylphosphonate and neutral phenylphosphonic acid ligands. The synthesis pathways of all three compounds were investigated in situ. A diffusion mechanism is corroborated by our findings. Intermediates could be detected and identified. The kinetically favored product (3) could always be detected during the syntheses. The thermodynamic stability of the compounds and the stoichiometric ratio of the starting materials are the two directing factors for the synthesis of the final products. KW - Mechanochemistry KW - Metal phosphonate KW - In situ KW - MOF KW - XRD PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-363322 DO - https://doi.org/10.1039/c6ra01080f SN - 2046-2069 VL - 6 IS - 42 SP - 36011 EP - 36019 PB - Royal Soc Chemistry CY - Cambridge, UK AN - OPUS4-36332 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Olejko, Lydia A1 - Cywinski, P. A1 - Bald, Ilko T1 - An ion-controlled four-color fluorescent telomeric switch on DNA origami structures N2 - The folding of single-stranded telomeric DNA into guanine (G) quadruplexes is a conformational change that plays a major role in sensing and drug targeting. The telomeric DNA can be placed on DNA origami nanostructures to make the folding process extremely selective for K+ ions even in the presence of high Na+ concentrations. Here, we demonstrate that the K+-selective G-quadruplex formation is reversible when using a cryptand to remove K+ from the G-quadruplex. We present a full characterization of the reversible switching between single-stranded telomeric DNA and G-quadruplex structures using Förster resonance energy transfer (FRET) between the dyes fluorescein (FAM) and cyanine3 (Cy3). When attached to the DNA origami platform, the G-quadruplex switch can be incorporated into more complex photonic networks, which is demonstrated for a three-color and a four-color FRET cascade from FAM over Cy3 and Cy5 to IRDye700 with G-quadruplex-Cy3 acting as a switchable transmitter. KW - DNA origami KW - FRET KW - Photonic wire KW - G quadruplex PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-362560 DO - https://doi.org/10.1039/C6NR00119J SN - 2040-3364 SN - 2040-3372 VL - 8 IS - 19 SP - 10339 EP - 10347 PB - Royal Soc Chemistry CY - Cambridge, UK AN - OPUS4-36256 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Resch-Genger, Ute A1 - Sloniec-Myszk, Jagoda ED - Hennig, Andreas T1 - Chiral, J-aggregate-forming dyes for alternative signal modulation mechanisms in self-immolative enzyme-activatable optical probes N2 - Enzyme-activatable optical probes are important for future advances in cancer imaging, but may easily suffer from low signal-to-background ratios unless not optimized. To address this shortcoming, numerous mechanisms to modulate the fluorescence signal have been explored. We report herein newly synthesized probes based on selfimmolative linkers containing chiral J-aggregate-forming dyes. Signal modulation by formation of chiral J-aggregates is yet unexplored in optical enzyme probe design. The comprehensive characterization of the probes by absorption, CD, fluorescence, and time-resolved fluorescence spectroscopy revealed dye−dye interactions not observed for the free dyes in solution as well as dye−protein interactions with the enzyme. This suggested that J-aggregate formation is challenging to achieve with current probe design and that interactions of the dyes with the Enzyme may interfere with achieving high signal-to-background ratios. The detailed understanding of the interactions provided herein provides valuable guidelines for the future design of similar probes. KW - Signal amplification KW - Fluorescence KW - Quantum yield KW - Optical spectroscopy KW - Dye KW - Cyanine KW - Characterization KW - Assay KW - Chiral KW - Aggregation KW - Activatable probe PY - 2016 DO - https://doi.org/10.1021/acs.jpcb.5b10526 SN - 1520-5207 SN - 1520-6106 VL - 120 IS - 5 SP - 877 EP - 885 PB - ACS Publications AN - OPUS4-35949 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Moser, Marko A1 - Kraft, Marco A1 - Würth, Christian A1 - Behnke, Thomas A1 - Falkenhagen, Jana A1 - Kaiser, Martin A1 - Muhr, V. A1 - Hirsch, T. T1 - Simple method for the quantification of PEG ligands and guidelines to the spectroscopic characterization of upconversion nanoparticles N2 - The surface modification of nanometer- and micrometer-sized particles with polyethylene glycol (PEG) ligands of varying length is a very common strategy to tune their hydrophilicity and biocompatibility, minimize unspecific interactions, improve biofunctionalization efficiencies, and enhance blood circulation times. Nevertheless, simple methods for the quantification of PEG ligands are rare. This is similarly true for the spectroscopic characterization of lanthanide-doped upconverting nanoparticles (UCNPs), novel near infrared (NIR)-excitable nonlinear fluorescence reporters for bioanalysis and theranostics, providing background-free multiple narrow emission bands in the visible and NIR, excellent photostability, and long luminescence lifetimes. We present here a simple method for the determination of the number of PEG ligands on nanomaterials and screening methods for the fast identification of nonradiative deaction pathways in UCNPs. T2 - SPIE Photonics West CY - San Francisco, CA, USA DA - 15.02.2016 KW - Optical assay KW - Fluorescence KW - Integrating sphere spectroscopy KW - Quantum yield KW - NIR KW - IR KW - Optical spectroscopy KW - Nanomaterials KW - Semiconducor nanocrystals KW - Upconversion nanocrystals KW - Surface analysis; KW - Ligand analysis PY - 2016 AN - OPUS4-35951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pohl, Rainer A1 - Kreutzbruck, Marc A1 - Commandeur, Colin A1 - Pelkner, Matthias T1 - Development of adapted GMR-probes for automated detection of hidden defects in thin steel sheets N2 - Thin steel sheets with a thickness of 0.3 mm and less are the base materials of many everyday life products (cans, batteries, etc.). Potential inhomogeneities such as non-metallic inclusions inside the steel can lead to a rupture of the sheets when it is formed into a product such as a beverage can. Therefore, there is a need to develop automated NDT techniques to detect hidden defects and inclusions in thin sheets during production. For this purpose Tata Steel Europe and BAM, the Federal Institute for Materials Research and Testing (Germany), collaborate in order to develop an automated NDT-system. Defect detection systems have to be robust against external influences, especially when used in an industrial environment. In addition, such a facility has to achieve a high sensitivity and a high spatial resolution in terms of detecting small inclusions in the μm-regime. In a first step, we carried out a feasibility study to determine which testing method is promising for detecting hidden defects and inclusions inside ferrous thin steel sheets. Therefore, two methods were investigated in more detail – magnetic flux leakage testing (MFL) using giant magneto resistance sensor arrays (GMR) as receivers [1,2] and eddy current testing (ET). The capabilities of both methods were tested with 0.2 mm-thick steel samples containing small defects with depths ranging from 5 μm up to 60 μm. Only in case of GMRMFL-testing, we were able to detect parts of the hidden defects with a depth of 10 μm trustworthily with a SNR better than 10 dB. Here, the lift off between sensor and surface was 250 μm. On this basis, we investigated different testing scenarios including velocity tests and different lift offs. In this contribution we present the results of the feasibility study leading to first prototypes of GMR-probes which are now installed as part of a demonstrator inside a production line. T2 - Review of Progress in Quantitative Nondestructive Evaluation CY - Minneapolis, MN, USA DA - 26.07.2015 KW - GMR KW - NDT PY - 2016 DO - https://doi.org/10.1063/1.4940464 VL - 1706 SP - Article Number: 020018 PB - Amer institute physics CY - Melville, New York, USA AN - OPUS4-36100 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Moraleja, I. A1 - Esteban-Fernández, Diego A1 - Lázaro, A. A1 - Humanes, B. A1 - Neumann, B. A1 - Tejedor, A. A1 - Mena, M. A1 - Jakubowski, Norbert A1 - Gómez-Gómez, M. T1 - Printing metal-spiked inks for LA-ICP-MS bioimaging internal standardization: comparison of the different nephrotoxic behavior of cisplatin, carboplatin, and oxaliplatin N2 - The study of the distribution of the cytostatic drugs cisplatin, carboplatin, and oxaliplatin along the kidney may help to understand their different nephrotoxic behavior. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) allows the acquisition of trace element images in biological tissues. However, results obtained are affected by several variations concerning the sample matrix and instrumental drifts. In this work, an internal standardization method based on printing an Ir-spiked ink onto the surface of the sample has been developed to evaluate the different distributions and accumulation levels of the aforementioned drugs along the kidney of a rat model. A conventional ink-jet printer was used to print fresh sagittal kidney tissue slices of 4 μm. A reproducible and homogenous deposition of the ink along the tissue was observed. The ink was partially absorbed on top of the tissue. Thus, this approach provides a pseudo-internal standardization, due to the fact that the ablation sample and internal standard take place subsequently and not simultaneously. A satisfactory normalization of LA-ICP-MS bioimages and therefore a reliable comparison of the kidney treated with different Pt-based drugs were achieved even for tissues analyzed on different days. Due to the complete ablation of the sample, the transport of the ablated internal standard and tissue to the inductively coupled plasma-mass spectrometry (ICP-MS) is practically taking place at the same time. Pt accumulation in the kidney was observed in accordance to the dosages administered for each drug. Although the accumulation rate of cisplatin and oxaliplatin is high in both cases, their Pt distributions differ. The strong nephrotoxicity observed for cisplatin and the absence of such side effect in the case of oxaliplatin could explain these distribution differences. The homogeneous distribution of oxaliplatin in the cortical and medullar areas could be related with its higher affinity for cellular transporters such as MATE2-k. KW - Bioimaging KW - LA-ICP-MS KW - Cisplatin KW - Standardization KW - Printed internal standard KW - Pt-based drugs KW - Nephrotoxicity PY - 2016 DO - https://doi.org/10.1007/s00216-016-9327-0 SN - 1618-2642 SN - 1618-2650 VL - 408 IS - 9 SP - 2309 EP - 2318 AN - OPUS4-36110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Würth, Christian A1 - Behnke, Thomas A1 - Moser, Marko A1 - Schneider, Ralf A1 - Kraft, Marco A1 - Pauli, Jutta A1 - Kaiser, Martin A1 - Güttler, Arne T1 - Methods for the determination of the optical properties and the surface chemistry of fluorescent particles N2 - Fluorescent particles like nm- and m-sized polymeric beads doped or labeled with different types of fluorophores and nanocrystalline systems like quantum dots and upconversion phosphors emitting in the visible (vis), near-infrared (NIR), and IR (infrared) region are of increasing importance as fluorescent reporters for bioanalysis and medical diagnostics. The assessment and comparison of material performance and the development of rational design strategies for improved systems requires suitable spectroscopic tools for the determination of signal-relevant optical properties and analytical tools for the determination of the number of surface groups, ligands, biomolecules and /or fluorophores per bead. In this respect, suitable spectroscopic tools for the characterization of the optical properties of such materials like photoluminescence quantum yields and brightness values and the determination of their surface chemistry are introduced. This includes integrating sphere setups for absolute measurements of fluorescence quantum yields of liquid and solid, transparent and scattering materials in the wavelength region of 350 nm to 1600 nm at varying excitation power densities for the study of multi-photon processes and simple optical assays, validated by comparison with established analytical techniques relying on different detection principles. Here, different examples for the optical and analytical characterization of different types of nanoscale reporters are presented. T2 - MoLife Research Seminar CY - Bremen, Germany DA - 26.04.2016 KW - Optical assay KW - Fluorescence KW - Integrating sphere spectroscopy KW - Quantum yield KW - NIR KW - IR KW - Optical spectroscopy KW - Nanomaterials KW - Semiconducor nanocrystals KW - Upconversion nanocrystals KW - Surface analysis KW - Ligand analysis PY - 2016 AN - OPUS4-35954 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Bartusch, Jürgen A1 - Schadow, Florian A1 - Köppe, Enrico A1 - Dohse, Elmar ED - Chimenti, D. E. ED - Bond, L. J. T1 - Focusing of ferroelectret air-coupled ultrasound transducers N2 - Air-coupled ultrasound has been applied increasingly as a non-destructive testing method for lightweight construction in recent years. It is particularly appropriate for composite materials being used in automotive and aviation industry. Air-coupled ultrasound transducers mostly consist of piezoelectric materials and matching layers. However, their fabrication is challenging and their signal-to-noise ratio often not sufficient for many testing requirements. To enhance the efficiency, air-coupled ultrasound transducers made of cellular polypropylene have been developed. Because of its small density and sound velocity, this piezoelectric ferroelectret matches the small acoustic impedance of air much better than matching layers applied in conventional transducers. In our contribution, we present two different methods of spherical focusing of ferroelectret transducers for the further enhancement of their performance in NDT applications. Measurements on carbon-fiber-reinforced polymer (CFRP) samples and on metal adhesive joints performed with commercially available focused air-coupled ultrasound transducers are compared to measurements executed with self-developed focused ferroelectret transducers. T2 - 42nd Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Minneapolis, Minnesota, USA DA - 26.07.2015 KW - Ferroelectret KW - Transducer KW - Air-coupled KW - Ultrasonic KW - Focusing PY - 2016 SP - 080001 PB - AIP Publishing CY - Melville, NY, USA AN - OPUS4-35955 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gaal, Mate A1 - Bovtun, Viktor A1 - Stark, Wolfgang A1 - Erhard, Anton A1 - Yakymenko, Y. A1 - Kreutzbruck, Marc T1 - Viscoelastic properties of cellular polypropylene ferroelectrets N2 - Viscoelastic properties of cellular polypropylene ferroelectrets (PP FEs) were studied at low frequencies (0.3–33 Hz) by dynamic mechanical analysis and at high frequencies (250 kHz) by laser Doppler vibrometry. Relaxation behavior of the in-plane Young’s modulus (Y´ 11~1500 MPa at room temperature) was observed and attributed to the viscoelastic response of polypropylene matrix. The out-of-plane Young’s modulus is very small (Y´33≈0.1 MPa) at low frequencies, frequency- and stress-dependent, evidencing nonlinear viscoelastic response of PP FEs. The highfrequency mechanical response of PP FEs is shown to be linear viscoelastic with Y´33≈0.8 MPa. It is described by thickness vibration mode and modeled as a damped harmonic oscillator with one degree of freedom. Frequency dependence of Y*33 in the large dynamic strain regime is described by the broad Cole-Cole relaxation with a mean frequency in kHz range attributed to the Dynamics of the air flow between partially closed air-filled voids in PP FEs. Switching-off the relaxation contribution causes dynamic crossover from the nonlinear viscoelastic regime at low frequencies to the linear viscoelastic regime at high frequencies. In the small strain regime, contribution of the air flow seems to be insignificant and the power-law response, attributed to the mechanics of polypropylene cell walls and closed air voids, dominates in a broad frequency range. Mechanical Relaxation caused by the air flow mechanism takes place in the sound and ultrasound frequency range (10 Hz–1MHz) and, therefore, should be taken into account in ultrasonic applications of the PP FEs deal with strong exciting or receiving signals. KW - Viscoelastic KW - Cellular polypropylene KW - Ferroelectret PY - 2016 DO - https://doi.org/10.1063/1.4944798 SN - 0021-8979 SN - 1089-7550 SN - 1520-8850 VL - 119 SP - Article Number: 125101 PB - AIP Publishing AN - OPUS4-35956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Staude, Andreas T1 - Computed tomography and its potential for cultural heritage studies N2 - Since the advent of industrial computed tomography (CT), this new analysis method has been used also for the investigation of objects of cultural heritage and art. CT provides the possibility to determine the inner and outer surfaces and to investigate the material structure without causing damage to the valuable objects. In this talk I will present examples of measurements performed at BAM, which demonstrate what CT can do for objects of diverse materials and for different objectives. T2 - Italian-German Worshop on "Technology and infrastructures for Cultural Heritage" CY - Bode-Museum, Berlin, Germany DA - 12.04.2016 KW - Computed tomography KW - Computertomographie KW - Cultural heritage KW - Art KW - Archaeology KW - Kulturelles Erbe KW - Kunst KW - Archäologie PY - 2016 AN - OPUS4-36162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neumann, Patrick P. A1 - Lazik, D. A1 - Bartholmai, Matthias T1 - Tomographic reconstruction of soil gas distribution from multiple gas sources based on sparse sampling N2 - A monitoring method is introduced that creates twodimensional (2D) maps of the soil gas distribution. The method combines linear gas sensing technology for in-situ monitoring of gases in soil with the mapping capabilities of Computed Tomography (CT) to reconstruct spatial and temporal resolved gas distribution maps. A weighted iterative algebraic reconstruction method based on Maximum Likelihood with Expectation Maximization (MLEM) in combination with a source-by-source reconstruction approach is introduced that works with a sparse setup of orthogonally-aligned linear gas sensors. The reconstruction method successfully reduces artifact production, especially when multiple gas sources are present, allowing the discrimination between true and non-existing so-called ghost source locations. Experimental validation by controlled field experiments indicates the high potential of the proposed method for rapid gas leak localization and quantification with respect to Pipeline or underground gas storage issues. KW - Computed tomography KW - Gas distribution mapping and gas source localization KW - Discrimination of multiple gas sources KW - Distributed linear sensor KW - Membrane-based gas sensing KW - Subsurface monitoring KW - Gas storage areas PY - 2016 DO - https://doi.org/10.1109/JSEN.2016.2545103 SN - 1530-437X VL - 16 IS - 11 SP - 4501 EP - 4508 PB - IEEE - Inst. Electrical Electronics Engineers Inc CY - Hoes Lane, NJ, USA AN - OPUS4-36228 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Jakubowski, Norbert T1 - Freddy Adams and Carlo Barbante: Chemical imaging analysis (Book review) N2 - In this book many practical hints are given and analytical problems are discussed by the authors from their own experiences. A critical assessment of the methods is given, which is most important for decision makers to select a good combination of complementary methods to solve practical analytical problems. KW - Chemical imaging analysis KW - Surface analysis KW - Interface analysis PY - 2016 DO - https://doi.org/10.1007/s00216-016-9517-9 SN - 1618-2642 SN - 1618-2650 VL - 408 IS - 16 SP - 4199 EP - 4201 PB - Springer AN - OPUS4-36216 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dietrich, Paul A1 - Nietzold, Carolin A1 - Weise, Matthias A1 - Unger, Wolfgang A1 - Alnabulsi, Saad A1 - Moulder, John T1 - XPS depth profiling of an ultrathin bioorganic film with an argon gas cluster ion beam N2 - The growing interest in artificial bioorganic Interfaces as a platform for applications in emerging Areas as personalized medicine, clinical diagnostics, biosensing, biofilms, prevention of biofouling, and other fields of bioengineering is the origin of a need for in Detail multitechnique characterizations of such layers and interfaces. The in-depth analysis of biointerfaces is of special interest as the properties of functional bioorganic coatings can be dramatically affected by in-depth variations of composition. In worst cases, the functionality of a device produced using such coatings can be substantially reduced or even fully lost. KW - XPS KW - Ar gas cluster gun KW - Depth profiling KW - Bioorganic film PY - 2016 UR - http://scitation.aip.org/content/avs/journal/bip/11/2/10.1116/1.4948341 DO - https://doi.org/10.1116/1.4948341 SN - 1934-8630 VL - 11 IS - 2 SP - 029603-1 EP - 029603-5 PB - American Vacuum Society CY - New York AN - OPUS4-36218 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gemeinert, Marion A1 - Kuchenbecker, Petra A1 - Steinborn, Gabriele A1 - Lindemann, Franziska A1 - Rabe, Torsten T1 - Stability assessment of ceramic high dielectric N2 - Resolution of capacitive sensors can be improved enormously by replacement of the dielectric material between the capacitor plates (e.g. air-dielectric) by a dielectric fluid with high permittivity. High dielectric liquid dispersions of ceramic micro and nano powders should be qualified as dielectric fluid with longtime shelf life. For this purpose it was necessary to produce stabilized ceramic suspensions with high particle concentration and to investigate sedimentation processes of the particles. Characterization of particles was done by use of zeta potential measurement, gas adsorption measurements (BET), density measurement with gas pycnometer as well as particle sizing by ultrasound spectroscopy and by use of an optical centrifuge. Shelf life of optimized electrostatic and steric stabilized ceramic suspension was investigated by use of an optical centrifuge, a LUMISizer 651 MW (LUM Ltd.) with STEP technology and front tracking analysis. Two different wave lengths – NIR (865 nm) and blue light (470 nm) were available for examination. Centrifugation measurements with different rotation speed were used to study the rheological behavior and the sedimentation process. By this way it was possible to achieve accelerated stability determination. Measured values could be used to simulate the sedimentation process under gravity acceleration and to predict shelf life for suspensions with different dispersants. T2 - PARTEC 2016 CY - Nürnberg, Germany DA - 19.04.2016 KW - Ceramic dispersion KW - Stability assessment KW - Analytical centrifuge KW - Shelf life prediction PY - 2016 AN - OPUS4-36184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scharlach, C. A1 - Müller, Larissa A1 - Wagner, S. A1 - Kobayashi, Y. A1 - Kratz, H. A1 - Ebert, M. A1 - Jakubowski, Norbert A1 - Schellenberger, E. T1 - LA-ICP-MS allows quantitative microscopy of europium-doped iron oxide nanoparticles and is a possible alternative to ambiguous Prussian blue iron staining N2 - The development of iron oxide nanoparticles for biomedical applications requires accurate histological evaluation. Prussian blue iron staining is widely used but may be unspecific when tissues contain substantial endogenous iron. Here we tested whether microscopy by laser ablation coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS) is sensitive enough to analyze accumulation of very small iron oxide particles (VSOP) doped with europium in tissue sections. KW - Atherosclerotic plaques KW - LA-ICP-MS microscopy KW - Quantification KW - Element microscopy KW - Histology PY - 2016 DO - https://doi.org/10.1166/jbn.2016.2230 SN - 1550-7033 SN - 1550-7041 VL - 12 IS - 5 SP - 1001 EP - 1010 AN - OPUS4-36189 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Werneburg, Martina A1 - Gebauer, J. A1 - Koch, Matthias T1 - In situ analysis of trichodiene as a volatile biomarker for the fast and non-invasive gas-phase analysis of cereal mycotoxins N2 - Typically, mycotoxigenic moulds and consequently small percentages of extremely contaminated portions (“hot spots”) are randomly distributed in a cereal lot. Therefore, an efficient sampling procedure for mycotoxin analysis represents a complex challenge for operators involving invasive and cost intensive steps. Establishing an in situ analysis of mycotoxins from the homogeneous gas-phase above cereal crops instead of analysing random samples could address this difficult issue. During studies for microbial volatile organic compounds (MVOCs) indicating an infection with Fusarium, trichodiene was identified as a unique biosynthesis intermediate of trichothecenes - one of the largest groups of the mycotoxin family. The sesquiterpene trichodiene is the only volatile biogenic precursor of the trichothecenes, thus, early and fast in situ detection of this biomarker might be of interest for a potential trichothecene infestation. However, there is no commercial trichodiene standard available needed for the quantification of trichodiene in cereal grains. The aim of the current project is to develop a fast, easy-to-handle and non-invasive gas-phase quantification of trichodiene in the field. Therefore, trichodiene was prepared by total synthesis based on a tandem orthoester Claisen rearrangement - oxidation - Robinson annulation strategy providing the racemic natural product in 9 steps and 8 % overall yield. Its structure was fully elucidated by NMR and MS. With the reference standard in hand, a protocol was established for the quantitative headspace analysis of trichodiene above crop spikes by GC/MS in the < 10 µg/kg range. Besides a sample survey and a trichodiene - trichothecene correlation study, it is aimed to transfer the validated analytical method from the laboratory into a field-portable analytical system. The fast and reliable in situ detection of trichodiene as a volatile biomarker for trichothecene mycotoxins will contribute to a reduction of food production/analysis costs and to an improvement of food safety. T2 - 38th Mycotoxin Workshop CY - Berlin, Germany DA - 02.05.2016 KW - Fungal Volatiles KW - Fusarium Mycotoxins KW - Trichodiene KW - Headspace Analysis KW - Synthesis PY - 2016 AN - OPUS4-36193 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heck, Christian A1 - Bald, Ilko A1 - Prinz, J. A1 - Merk, V. A1 - Kneipp, Janina A1 - Dathe, André A1 - Fritzsche, W. T1 - Plasmonic gold nanolenses self-assembled by DNA origami N2 - Surface-enhanced Raman scattering (SERS) exploits the enhancement of electromagnetic fields in close vicinity of plasmonic nanostructures. The nanometer-scale spatial arrangement of plasmonic metal nanoparticles and analyte molecules has a significant effect on the observed signal enhancements and represents a great challenge in this technique. Especially interesting effects are expected for complex gold nanolenses (AuNLs), consisting of three or more differently-sized AuNPs. We use DNA origami to assemble AuNLs with 10, 20 and 60 nm AuNPs, arranged in three different geometries. Using correlated AFM and Raman spectroscopy, and probing single AuNLs, we systematically examined the SERS properties of the three different assemblies. T2 - DNA Nanotechnology 2016 CY - Jena, Germany DA - 19.05.2016 KW - gold nanoparticles KW - DNA origami KW - plasmonics PY - 2016 AN - OPUS4-36205 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ortel, Erik A1 - Häusler, Ines A1 - Österle, Werner A1 - Narbey, S. A1 - Oswald, F. A1 - Andersen, I. H. A1 - Holzweber, Markus A1 - Unger, Wolfgang A1 - Hodoroaba, Vasile-Dan T1 - In-depth structural and chemical characterization of engineered TiO2 films N2 - Analytical routines for a comprehensive in-depth morphological, structural, and chemical characterization of functionalized TiO2 films by using different state-of-the-art analytical techniques are presented and discussed with the main objective to identify potential reference TiO2 coating parameters able to be certified at a later stage. TiO2 films fabricated by two different synthetic procedures as representative for two main large-scale applications were selected: (i) pulsed d.c. magnetron sputtering for photocatalytic applications and (ii) screen printing from preformed anatase nanoparticles. The screen-printed films were further loaded with a sensitizing dye for application as a dye-sensitized solar cell. Film properties such as microstructure and crystallographic texture of pulsed d.c. magnetron sputtering synthesized films were systematically studied by means of scanning nanobeam electron diffraction in a transmission electron microscope and the surface and inner morphology by scanning electron microscopy. The dye distribution over the depth of screen-printed TiO2 layers was analyzed before and after dye-loading by means of energy dispersive X-ray spectroscopy at scanning electronmicroscope, Auger electron spectroscopy and time-of-flight secondary ion mass spectrometry. The long-term goal of the present study is the improvement of quality of the TiO2 film parameters as measured by using different types of reference TiO2 coatings having specific parameters certified. T2 - 16th European Conference on Applications of Surface and Interface Analysis ECASIA'15 CY - Granada, Spain DA - 28.09.2015 KW - Mapping KW - Line scan KW - Depth profiling KW - TiO2 films KW - Crystallinity KW - Ru dye sensitizer PY - 2016 DO - https://doi.org/10.1002/sia.5966 SN - 0142-2421 SN - 1096-9918 VL - 48 SP - 664 EP - 669 PB - John Wiley & Sons, Ltd. AN - OPUS4-36791 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Babick, F. A1 - Mielke, Johannes A1 - Wohlleben, W. A1 - Weigel, St. A1 - Hodoroaba, Vasile-Dan T1 - How reliably can a material be classified as a nanomaterial? Available particle-sizing techniques at work N2 - Currently established and projected regulatory frameworks require the classification of materials (whether nano or non-nano) as specified by respective definitions, most of which are based on the size of the constituent particles. This brings up the question if currently available techniques for particle size determination are capable of reliably classifying materials that potentially fall under these definitions. In this study, a wide variety of characterisation techniques, including counting, fractionating, and spectroscopic techniques, has been applied to the same set of materials under harmonised conditions. The selected materials comprised well-defined Quality control materials (spherical, monodisperse) as well as industrial materials of complex shapes and considerable polydispersity. As a result, each technique could be evaluated with respect to the determination of the number-weighted median size. Recommendations on the most appropriate and efficient use of techniques for different types of material are given. KW - Nanomaterial classification KW - Nanoparticle KW - Number-weighted median size KW - Tiered KW - Particle size analysis KW - Nanometrology KW - Characterisation techniques PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367922 UR - http://link.springer.com/article/10.1007/s11051-016-3461-7 DO - https://doi.org/10.1007/s11051-016-3461-7 SN - 1388-0764 SN - 1572-896X VL - 18 IS - 6 SP - Article 158, 1 EP - 40 PB - Springer AN - OPUS4-36792 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Detjens, Marc A1 - Tiebe, Carlo A1 - Banach, Ulrich A1 - Majewski, J. A1 - Hübert, Thomas T1 - Coulometric trace humidity measurement in industrial gases N2 - Coulometric sensors are applied for trace humidity measurements in various technical gases. The use of this sensor type is demanded in some standards by the European Pharmacopoeia for medical gases. Coulometric sensors allow the measurement of water vapour in gases such as e.g. air, Cl2, H2, N2, N2O, CH4 between the concentration ranging from 0.1 to 2,500 µmol∙mol-1 which corresponds to frost point temperature -90 °C to -10 °C, respectively. The sensing principle is based on Faraday’s law of electrolysis whereby water is decomposed to hydrogen and oxygen. The sensor signal is the measured electrical current which is proportional to the mass of water that is absorbed on the hygroscopic phosphorous pentoxide layer. The signal is dependent on the gas flow at a given voltage, gas pressure and temperature. The sensors need to be calibrated to measure the accurate signal for humidity in air. However, the signal is dependent on the type of gas matrix. This dependency has not been quantified so far. Therefore, the impact of reactive gases such as hydrogen and nitrous oxide on the calibration curve was investigated. Furthermore, a possible rationale in relation to the interaction of water with the gas matrix and its impact on the electrode reactions is suggested. The experimental setup consists of a gas supply, dryer, humidifier, test chamber and reference hygrometer. The test gas is generated by mixing the dry and the wet gas flow. First the carrier gas is dried by an activated carbon filter and then split into two flows. One flow is dried again with a molecular sieve. The other flow is humidified by passing it through a bubbler filled with pure water. After this, the rate of both flows is controlled by mass flow controllers and then mixed with the test gas. A calibrated precision chilled mirror dew-point hygrometer is used as a reference instrument. The coulometric sensors were exposed to different humidified gases and the sensor signal was recorded till a constant value was obtained. Calibration curves were calculated for the frost point temperature in the range of about -70 °C to -10 °C according to the equation, tf = A + B∙ln(I), (I is the electrolysis current and A, B are constants) followed with a linear regression fit. Comparison of the results of air and nitrogen showed no significant differences. In contrast, there are remarkable differences for humidified hydrogen and nitrous oxide, respectively. The difference might be due to increased recombination of hydrogen with the produced oxygen to form new water molecules in humidified hydrogen. In conclusion, coulometric trace humidity sensor is a robust hygrometer for various technical applications. However it needs to be calibrated for the specific gas matrix. T2 - Tempmeko 2016 CY - Zakopane, Poland DA - 27.06.2016 KW - Trace humidity KW - Coulometric sensor KW - Industrial gases PY - 2016 AN - OPUS4-36793 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -