TY - GEN A1 - Gunella, F. A1 - Kunisch, E. A1 - Maenz, S. A1 - Horbert, V. A1 - Xin, L. A1 - Mika, J. A1 - Borowski, J. A1 - Bischoff, S. A1 - Schubert, H. A1 - Sachse, A. A1 - Illerhaus, Bernhard A1 - Günster, Jens A1 - Bossert, J. A1 - Jandt, K. D. A1 - Plöger, F. A1 - Kinne, R. W. A1 - Brinkmann, O. A1 - Bungartz, M. ED - Carragee, T1 - The GDF5 mutant BB-1 enhances the bone formation induced by an injectable, poly(l-lactide-co-glycolide) acid (PLGA) fiber-reinforced, brushite-forming cement in a sheep defect model of lumbar osteopenia N2 - BACKGROUND CONTEXT: Targeted delivery of osteoinductive bone morphogenetic Proteins (eg, GDF5) in bioresorbable calcium phosphate cement (CPC), potentially suitable for vertebroplasty and kyphoplasty of osteoporotic vertebral fractures, may be required to counteract augmented local bone catabolism and to support complete bone regeneration. The biologically optimized GDF5 Mutant BB-1 may represent an attractive drug candidate for this purpose. PURPOSE: The aim of the current study was to test an injectable, poly (l-lactide-co-glycolide) acid (PLGA) fiber-reinforced, brushite-forming CPC containing low-dose BB-1 in a sheep lumbar osteopenia model. STUDY DESIGN/ SETTING: This is a prospective experimental animal study. METHODS: Bone defects (diameter 5 mm) were generated in aged, osteopenic female sheep and were filled with fiber-reinforced CPC alone (L4; CPC+fibers) or with CPC containing different dosages. KW - Bone morphogenetic protein; KW - Bone regeneration; KW - Micro-Computed-Tomography; KW - Calcium phosphate cement; KW - GDF-5 mutant; KW - Large animal model sheep; KW - Osteoporotic vertebral fracture PY - 2018 DO - https://doi.org/10.1016/j.spinee.2017.10.002 SN - 1529-9430 SN - 1878-1632 VL - 18 IS - 2 SP - 357 EP - 369 PB - Elsevier CY - New York AN - OPUS4-44561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maul, Ronald A1 - Borzekowski, Antje A1 - Drewitz, Tatjana A1 - Keller, Julia A1 - Pfeifer, Dietmar A1 - Kunte, Hans-Jörg A1 - Koch, Matthias A1 - Rohn, S. T1 - Biosynthesis of zearalenone conjugates by fungi N2 - Zearalenone (ZEN) and its sulfate and glucoside conjugates have been detected in (a broad variety of) food and feed commodities1. Both conjugated derivatives are formed as part of fungal or plant secondary metabolism and thus, belong to the group of modified mycotoxins2. After consumption of contaminated foodstuff, the conjugates can be hydrolyzed by human intestinal microbiota leading to liberation of ZEN that implies an underestimation of the true ZEN exposure. In order to include ZEN conjugates in routine analysis, as well as for toxicological investigation reliable standards are needed. The objective of the present study was to develop a simple and economic method for biosynthesis of ZEN conjugates. Preceding experiments on the biotransformation of ZEN by Rhizopus and Aspergillus species showed a mixed metabolite formation3. Therefore, these known ZEN conjugating fungal strains were screened for their potential to selectively synthesize the ZEN derivatives ZEN-14-sulfate (Z14S), ZEN-14-glucoside (Z14G) and ZEN-16-glucoside (Z16G). The screening was conducted by adding ZEN to liquid fungal cultures. Cultivation conditions and ZEN incubation time were varied. All media samples were analyzed for metabolite formation by HPLC-MS/MS. Z14S was exclusively formed by A. oryzae. Under optimized conditions a specific biosynthesis of Z14G by R. oryzae and Z16G by R. oligosporus was achieved. After liquid-liquid-extraction and preparative chromatographic cleanup 1H-NMR purities of ≥ 73% for Z14S, ≥ 82% for Z14G and ≥ 50% for Z16G were obtained. In addition, a consecutive biosynthesis was developed by first using Fusarium graminearum for ZEN biosynthesis on rice based liquid medium. After inactivation of Fusarium the subsequent conjugation reaction was conducted utilizing Aspergillus and Rhizopus species under the various optimized conditions. In this study an easy and cost-efficient biosynthesis for Z14S, Z14G and Z16G was developed. The developed biosynthesis could be also used for other metabolites like ZEL conjugates. Our results of the in vitro screening indicate also the formation of a ZEL-glucoside and α ZEL-sulfate as major metabolites by R. oryzae. In sum, under optimized cultivation conditions fungi can be easily utilized for a targeted and stereospecific synthesis of ZEN conjugates. T2 - 10th World Mycotoxin Forum Conference CY - Amsterdam, The Netherlands DA - 12.03.2018 KW - Mycotoxins KW - Food safety KW - Analytical standards PY - 2018 AN - OPUS4-44547 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Terborg, R. A1 - Hodoroaba, Vasile-Dan T1 - Analysis of the elemental composition and thickness of a Fe-Ni film on Si using Bruker ESPRIT and SAMx STRATAGem N2 - Quantitative analysis of a bulk sample requires that the composition of the sample is homogeneous over the analyzed volume. For inhomogenous samples the calculation of the matrix effects is not correct and this can lead to wrong results in the element concentrations. For samples containing a layer structure a different quantitative evaluation has to be applied. This can be provided with the standard-based analysis in ESPRIT in combination with the STRATAGem software. KW - Thin film analysis KW - SEM/EDX KW - EPMA KW - k-values PY - 2018 UR - https://www.bruker.com/products/x-ray-diffraction-and-elemental-analysis/eds-wds-ebsd-sem-micro-xrf-and-sem-micro-ct/quantax-eds-for-sem/applications/layer-analysis.html SP - 1 EP - 4 CY - Berlin AN - OPUS4-44594 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gottlieb, Cassian A1 - Günther, Tobias A1 - Wilsch, Gerd T1 - Impact of grain sizes on the quantitative concrete analysis using laser-induced breakdown spectroscopy N2 - In civil engineering concrete is the most used building material for making infrastructures like bridges and parking decks worldwide. It is as a porous and multiphase material made of aggregates with a defined grain size distribution, cement and water as well as different additives and admixtures depending on the application. Different grain sizes are important to ensure the needed density and compressive strength. The resulting porous cement matrix contains a mixture of flour grains (aggregates with a grain size below 125 lm) and cement particles (particle size≈50lm). Harmful species like chlorides may penetrate together with water through the capillary pore space and may trigger different damage processes. The damage assessment of concrete structures in Germany is estimated due to the quantification of harmful elements regarding to the cement content only. In the evaluation of concrete using LIBS a two-dimensional scanning is necessary to consider the heterogeneity caused by the aggregates. Therefore, a LIBS system operating with a low energy NdCr:YAG laser, a pulse energy of 3 mJ, a wavelength of 1064 nm, a pulse width of 1.5 ns and a Repetition rate of 100 Hz has been used. Different Czerny-Turner spectrometers with CCD detectors in the UV and NIR range have been used for the detection. Large aggregates (macro-heterogeneity) can be excluded from the evaluation, whereas small aggregates in the range of the laser spot size (flour grains) cannot be spatially resolved. In this work the micro heterogeneity caused by flour grains and their impact on the quantification with LIBS will be discussed. To analyze the effect of changing grain sizes and ratios, the ablation behavior has been determined and compared. Samples with defined grain sizes were made and analyzed using LIBS. The grain size distributions were analyzed with laser diffraction (LDA). KW - LIBS KW - Concrete KW - Micro heterogeneity KW - Grain sizes PY - 2018 DO - https://doi.org/10.1016/j.sab.2018.02.004 SN - 0584-8547 SN - 0038-6987 VL - 142 SP - 74 EP - 84 PB - Elsevier AN - OPUS4-44595 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinen, S. A1 - Rackow, S. A1 - Cuellar-Camacho, J. L. A1 - Donskyi, Ievgen A1 - Unger, Wolfgang A1 - Weinhart, M. T1 - Transfer of functional thermoresponsive poly(glycidyl ether) coatings for cell sheet fabrication from gold to glass surfaces N2 - Thermoresponsive polymer coatings can facilitate cell sheet fabrication under mild conditions by promoting cell adhesion and proliferation at 37 1C. At lower temperatures the detachment of confluent cell sheets is triggered without enzymatic treatment. Thus, confluent cell sheets with intact extracellular matrix for regenerative medicine or tissue engineering applications become available. Herein, we applied the previously identified structural design parameters of functional, thermoresponsive poly(glycidyl ether) brushes on gold to the more application-relevant substrate glass via the self-assembly of a corresponding block copolymer (PGE-AA) with a short surface-reactive, amine-presenting anchor block. Both, physical and covalent immobilization on glass via either multivalent ionic interactions of the anchor block with bare glass or the coupling of the anchor block to a polydopamine (PDA) adhesion layer on glass resulted in stable coatings. Atomic force microscopy revealed a high degree of roughness of covalently attached coatings on the PDA adhesion layer, while physically attached coatings on bare glass were smooth and in the brush-like regime. Cell sheets of primary human dermal fibroblasts detached reliably (86%) and within 20 ± 10 min from physically tethered PGE-AA coatings on glass when prepared under cloud point grafting conditions. The presence of the laterally inhomogeneous PDA adhesion layer, however, hindered the spontaneous temperature-triggered cell detachment from covalently grafted PGE-AA, decreasing both detachment rate and reliability. Despite being only physically attached, self-assembled monolayer brushes of PGE-AA block copolymers on glass are functional and stable thermoresponsive coatings for application in cell sheet fabrication of human fibroblasts as determined by X-ray photoelectron spectroscopy. KW - X-ray photoelectron spectroscopy KW - Thermoresponsive poly(glycidyl ether) coatings KW - Cell sheet fabrication KW - Nm film thickness PY - 2018 DO - https://doi.org/10.1039/c7tb03263c SN - 2050-750X SN - 2050-7518 VL - 6 IS - 10 SP - 1489 EP - 1500 PB - The Royal Society of Chemistry AN - OPUS4-44600 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kjaervik, Marit A1 - Schwibbert, Karin A1 - Dietrich, P. A1 - Thissen, A. A1 - Unger, Wolfgang T1 - Surface characterisation of biofilms by nearambient pressure X-ray photoelectron spectroscopy N2 - The XPS information depth of approximately 10 nm is in the same size range as the outer membrane of the gram-negative bacteria, which makes XPS a suitable tool for determining the elemental composition of the bacterial surface and monitor changes caused by outer stress like dehydration or exposure to antimicrobials. However, bacteria are inherently in a hydrated state, and therefore only compatible to ultra-high vacuum after extensive sample preparation, which may degrade the sample constituents. This issue is addressed by the development of near-ambient pressure (NAP)-XPS, which enables bacteria and biofilms to be characterised in their native wet state. Artificial biofilms, bacteria and biofilms of Escherichia coli have been characterised with the laboratory NAP-XPS instrument EnviroESCA from SPECS GmbH, at pressures ranging from high vacuum to 12 mbar, and in both humid and dry environment. By studying biological samples in their native wet state, new insight about composition and transport of drugs through cell membranes and the extracellular polymeric substance (EPS) of biofilms can be obtained. T2 - Royal Society of Chemistry Twitter Conference CY - Worldwide (online conference) DA - 06.03.2018 KW - Biofilms KW - E. coli KW - Alginate KW - NAP-XPS PY - 2018 AN - OPUS4-44498 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kjaervik, Marit A1 - Schwibbert, Karin A1 - Dietrich, P. A1 - Thissen, A. A1 - Unger, Wolfgang T1 - Surface characterisation of bacteria and biofilms by NAP-XPS N2 - The XPS information depth of approximately 10 nm is in the same size range as the outer membrane of the gram-negative bacteria, which makes XPS a suitable tool for determining the elemental composition of the bacterial surface and monitor changes caused by outer stress like dehydration or exposure to antimicrobials. However, bacteria are inherently in a hydrated state, and therefore only compatible to ultra-high vacuum after extensive sample preparation, which may degrade the sample constituents. This issue is addressed by the development of near-ambient pressure (NAP)-XPS, which enables bacteria and biofilms to be characterised in their native wet state. Artificial biofilms, bacteria and biofilms of Escherichia coli have been characterised with the laboratory NAP-XPS instrument EnviroESCA from SPECS GmbH, at pressures ranging from high vacuum to 12 mbar, and in both humid and dry environment. By studying biological samples in their native wet state, new insight about composition and transport of drugs through cell membranes and the extracellular polymeric substance (EPS) of biofilms can be obtained. In this contribution, the latest progress on biofilm characterisation by NAP-XPS will be presented, and measurement capabilities and limitations will be discussed. T2 - Die Frühjahrstagung der Deutsche Physikalische Gesellschaft CY - Berlin, Germany DA - 12.03.2018 KW - Biofilms KW - E. coli KW - Alginate KW - NAP-XPS PY - 2018 AN - OPUS4-44500 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Madkour, Sherif A1 - Schönhals, Andreas T1 - Dynamics of nanoscopically confined PVME in thin films of an asymmetric PVME/PS blend N2 - In recent years, substantial efforts have been devoted to investigating nanoscopic confinement of polymers, and its effect on glassy dynamics. Broadband Dielectric Spectroscopy (BDS) was used to study the dynamics of ultra-thin films of PVME/PS 50/50 wt% blend, employing a novel nano-structured capacitor sample arrangement. The investigated system shows a complex dynamic behavior. First, an α-relaxation, related to a bulk-like layer was found. Second, an α’-relaxation was observed, characteristic for dynamically asymmetric blends, where the out of equilibrium dynamics is attributed to weakly-cooperative PVME segments relaxing within a frozen environment of PS segments. Thirdly, for thinnest films, an Arrhenius-like process was dominant in the dielectric spectra, indicating localized fluctuations of the segments. Relaxation rates of this process resembled that of the degenerated α-relaxation of the adsorbed layer, found for pure PVME, thus it was assigned accordingly. For thinnest films, this process undergoes a further confinement, due to the topological constraints, introduced by PS. Such multiple confinement effect has not been reported for ultra-thin films of polymer blends, before this study. T2 - Spring Meeting of German Physical Society CY - Berlin, Germany DA - 12.03.2018 KW - Thin polymeric films PY - 2018 AN - OPUS4-44502 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rhode, Michael A1 - Mente, Tobias A1 - Steppan, E. A1 - Kannengießer, Thomas A1 - Steger, J. T1 - Hydrogen trapping in T24 Cr-Mo-V steel weld joints - microstructure effect vs. experimental influence on activation energy for diffusion N2 - Hydrogen-assisted cracking is a critical combination of local microstructure, mechanical load and hydrogen concentration. Welded microstructures of low-alloyed creep-resistant Cr-Mo-V steels show different hydrogen trapping kinetics. This influences the adsorbed hydrogen concentration as well as the diffusion by moderate or strong trapping. A common approach to describe hydrogen traps is by their activation energy that is necessary to release hydrogen from the trap. In the present study, Cr-Mo-V steel T24 (7CrMoVTiB10-10) base material and TIG weld metal were investigated. Electrochemically hydrogen charged specimens were analyzed by thermal desorption analysis (TDA) with different linear heating rates. The results show two different effects. At first, the microstructure effect on trapping is evident in terms of higher hydrogen concentrations in the weld metal and increased activation energy for hydrogen release. Secondly, it is necessary to monitor the real specimen temperature. A comparison between the adjusted heating rate and the real specimen temperature shows that the calculated activation energy varies by factor two. Thus, the trap character in case of the base material changes to irreversible at decreased temperature. Hence, the effect of the experimental procedure must be considered as well if evaluating TDA results. Finally, realistic temperature assessment is mandatory for calculation of activation energy via TDA. KW - Creep-resistant steel KW - Hydrogen assisted cracking KW - Thermal desorption analysis KW - Welding KW - Microstructure KW - Diffusion PY - 2018 DO - https://doi.org/10.1007/s40194-017-0546-6 SN - 0043-2288 SN - 1878-6669 VL - 62 IS - 2 SP - 277 EP - 287 PB - Springer CY - Berlin, Heidelberg AN - OPUS4-44505 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Coelho Lima, Isabela A1 - Grohmann, Maria A1 - Niederleithinger, Ernst T1 - Alternative imaging conditions for reverse-time migration N2 - Poster on the evaluation of several imaging conditions for reverse time migration, applied to ultrasonic echo data, tested with synthetic (simulated) dat and real data from a polyamide model. T2 - Jahrestagung der Deutschen geophysikalischen Gesellschaft CY - Leoben, Austria DA - 12.2.2018 KW - Ultrasound KW - Reverse time migration KW - Imaging condition KW - Concrete KW - Polyamide PY - 2018 AN - OPUS4-44583 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -