TY - JOUR A1 - Czuban, M. A1 - Kulka, M. W. A1 - Wang, L. A1 - Koliszak, A. A1 - Achazi, K. A1 - Schlaich, C. A1 - Donskyi, Ievgen A1 - Di Luca, M. A1 - Mejia Oneto, J. M. A1 - Royzen, M. A1 - Haag, R. A1 - Trampuz, A. T1 - Titanium coating with mussel inspired polymer and bio-orthogonal chemistry enhances antimicrobial activity against Staphylococcus aureus N2 - Implant-associated infections present severe and difficult-to-treat complications after surgery, related to implant biofilm colonization. Systemic administration of antibiotics cannot reach sufficient concentrations at the infected site and may be toxic. Here we describe how mussel-inspired dendritic material coated on a titanium surface can locally activate a prodrug of daptomycin (pro-dapto) to treat methicillin-resistant Staphylococcus aureus. The mechanism of the prodrug activation is based on bio-orthogonal click chemistry between a tetrazine (Tz) and trans-cyclooctene (TCO). The former is attached to the dendritic polymer, while the later converts daptomycin into a prodrug. Characterization of the material's properties revealed that it is hydrophobic, non-toxic, and stable for a prolonged period of time. We envision that the titanium coated dendritic material will be able to improve the treatment of implant-associated infections by concentrating systemically administered antibiotic prodrugs, thus converting them into active localized medicines. KW - Bio-orthogonal chemistry KW - Antimicrobial titanium coating KW - Prodrug antibiotic KW - Antibiotic delivery KW - Antibiotic release KW - XPS PY - 2020 DO - https://doi.org/10.1016/j.msec.2020.111109 VL - 116 SP - 111109 PB - Elsevier B.V. AN - OPUS4-51204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klöckner, P. A1 - Seiwert, B. A1 - Eisentraut, Paul A1 - Braun, Ulrike A1 - Reemtsma, T. A1 - Wagner, S. T1 - Characterization of tire and road wear particles from road runoffindicates highly dynamic particle properties N2 - Tire and road wear particles (TRWPs) are heteroagglomerates of tire rubber and other particles deposited on the road surface and one of the main contributors to non-exhaust emissions of automobile traffic. In this study, samples from road environments were analyzed for their TRWP contents and concentra- tions of eight organic tire constituents. TRWP concentrations were determined by quantifying Zn in the density fraction < 1.9 g/cm ³and by thermal extraction desorption-gas chromatography-mass spectrometry (TED-GC/MS) and the concentrations ranged from 3.7 to 480 mg TRWP/g. Strong and statistically signif- icant correlations with TRWPs were found for 2-hydroxybenzothiazole and 2-aminobenzothiazole, indi- cating that these substances may be suitable markers of TRWPs. The mass distribution of TRWPs in road dust suggests that the main mass fraction formed on roads consists of coarse particles ( > 100 μm). Data for a sedimentation basin indicate that the fine fraction ( < 50 μm) is preferentially transported by road runoffinto receiving waters. The size distribution and density data of TRWP gathered by three different quantitation approaches also suggest that aging of TRWPs leads to changes in their particle density. An improved understanding of the dynamics of TRWP properties is essential to assess the distribution and dissipation of this contaminant of emerging concern in the environment. KW - Tire Wear KW - Density separation KW - Microplastic KW - Urban PY - 2020 DO - https://doi.org/10.1016/j.watres.2020.116262 VL - 185 SP - 116262 PB - Elsevier Ltd. AN - OPUS4-51256 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Sennikov, P. A1 - Kornev, R. A1 - Ermakov, A. A1 - Shkrunin, V. T1 - Laser Induced Dielectric Breakdown for Chemical Vapor Deposition by Hydrogen Reduction of Volatile Boron Halides BCl3 and  BF3 N2 - A possibility of deposition from laser-induced plasma is investigated in search for an economic and simple method for obtaining isotopic compounds from enriched gaseous precursors although no isotopic compounds are used in this the proof-of-principle work. A breakdown in mixtures of BCl3 and BCl3 with hydrogen, argon, and methane are studied both theoretically and experimentally. Equilibrium chemistry calculations show the deposition of boron, boron carbide, and carbon is thermodynamically favorable in BCl3 systems and only carbon in BF3 systems. Dynamic calculation of expanding plasma is performed using fluid dynamics coupled with equilibrium chemistry. Condensed phases of boron, boron carbide, and graphite are predicted with maximum concentrations in peripheral zones of the plasma. In experiment, plasma is induced in mixtures BCl3, H2 + BCl3, H2 + Ar + BCl3, H2 + BCl3 + CH4, BF3, H2 + BF3, H2 + Ar + BF3, and H2 + Ar + BF3. The gases are analyzed before, during, and after laser irradiation by optical and mass spectrometry methods. The results show the composition of reaction products close to that predicted theoretically. The conversion of precursor gases BCl3 and BF3 into gaseous and condensed products is 100% for BCl3 and 80% for BF3. Solid deposits of up to 30 mg are obtained from all reaction mixtures. Due to technical reasons only FTIR characterization of the BCl3 + H2 + CH4 deposit is done. It points to presence of condensed boron and boron carbide predicted by the model. Overall, the calculations and preliminary experimental results imply the chemical vapor deposition with laser induced plasma is promising for conversion of gaseous enriched precursors into elemental isotopes and their isotopic compounds. KW - Boron halides KW - Chemical vapor deposition KW - Laser induced dielectric breakdown, Hydrogen reduction PY - 2020 DO - https://doi.org/10.1007/s11090-020-10096-w VL - 40 IS - 5 SP - 1145 EP - 1162 PB - Springer AN - OPUS4-50968 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kruschwitz, Sabine A1 - Halisch, M. A1 - Dlugosch, R. A1 - Prinz, Carsten T1 - Toward a better understanding of low-frequency electrical relaxation - An enhanced pore space characterization N2 - Relaxation phenomena observed in the electrical low-frequency range (approximately 1 mHz-10 kHz) of natural porous media like sandstones is often assumed to be directly related to the dominant (modal) pore throat sizes measured, for instance, with mercury intrusion porosimetry. Attempts to establish a universally valid relationship between pore size and peak Spectral Induced Polarization (SIP) relaxation time have failed, considering sandstones from very different origins and featuring great variations in textural and chemical compositions as well as in geometrical pore space properties. In addition working with characteristic relaxation times determined in Cole-Cole or Debye decomposition fits to build the relationship have not been successful. In particular, samples with narrow pore throats are often characterized by long SIP relaxation times corresponding to long “characteristic length scales” in these media, assuming that the diffusion coefficients along the electrical double layer were constant. Based on these observations, three different types of SIP relaxation can be distinguished. We present a new way of assessing complex pore spaces of very different sandstones in a multi-methodical approach to combine the benefits of mercury intrusion porosimetry, micro-computed tomography, and nuclear magnetic resonance. In this way, we achieve much deeper insight into the pore space due to the different resolutions and sensitivities of the applied methods to both pore constrictions (throats) and wide pores (pore bodies). We experimentally quantify pore aspect ratios and volume distributions within the two pore regions. We clearly observe systematic differences between three SIP relaxation types identified previously and can attribute the SIP peak relaxation times to measured characteristic length scales within our materials. We highlight selected results for a total of nine sandstones. It seems that SIP relaxation behavior depends on the size difference of the narrow pore throats to the wide pore bodies, which increases from SIP Type 1 to Type 3. KW - µ-CT KW - Spectral induced polarization KW - Nuclear magnetic resonance KW - Pore space PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509763 DO - https://doi.org/10.1190/GEO2019-0074.1 SN - 0016-8033 VL - 85 IS - 4 SP - MR257 EP - MR270 PB - Society of Exploration Geophysicists AN - OPUS4-50976 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Donskyi, Ievgen A1 - Chen, Y. A1 - Nickl, Philip A1 - Guday, G. A1 - Qiao, H. A1 - Achasi, K. A1 - Lippitz, Andreas A1 - Unger, Wolfgang A1 - Böttcher, C. A1 - Chen, W. A1 - Adeli, M. A1 - Haag, R. T1 - Self-degrading graphene sheets for tumor therapy N2 - Low biodegradability of graphene derivatives and related health risks are the main limiting factors for their in vivo biomedical applications. Here, we present the synthesis of enzyme-functionalized graphene sheets with self-degrading properties under physiological conditions and their applications in Tumor therapy. The synergistic enzyme cascade glucose oxidase and myeloperoxidase are covalently conjugated to the surface of graphene sheets and two-dimensional (2D) platforms are obtained that can produce sodium hypochlorite from glucose. The enzyme-functionalized graphene sheets with up to 289 nm average size are degraded into small pieces (≤40 nm) by incubation under physiological conditions for 24 h. Biodegradable graphene sheets are further loaded with doxorubicin and their ability for Tumor therapy is evaluated in vitro and in vivo. The laser-triggered release of doxorubicin in combination with the enzymatic activity of the functionalized graphene sheets results in a synergistic antitumor activity. Taking advantage of their neutrophil-like activity, fast biodegradability, high photo- and chemotherapeutic effects, the novel two-dimensional nanoplatforms can be used for tumor therapeutic applications. KW - Graphene KW - Self-degrading KW - Thumor therapy KW - XPS KW - NEXAFS PY - 2020 DO - https://doi.org/10.1039/d0nr02159h SP - 1 EP - 12 PB - The Royal Society of Chemistry AN - OPUS4-50978 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rus, J. A1 - Gustschin, A. A1 - Mooshofer, H. A1 - Grager, J.-C. A1 - Bente, Klaas A1 - Gaal, Mate A1 - Pfeiffer, F. A1 - Grosse, C. U. T1 - Qualitative comparison of non-destructive methods for inspection of carbon fiber-reinforced polymer laminates N2 - In the rapidly expanding composite industry, novel inspection methods have been developed in recent years. Particularly promising for air-coupled testing are cellular polypropylene transducers which offer better impedance matching to air than piezoelectric transducers. Furthermore, broadband transmitters (laser-induced ultrasound and thermoacoustic emitters) and receivers (optical microphones) have opened a completely new chapter for advanced contact-free ultra-sound inspection. X-ray dark-field radiography offers a different approach to detect porosity and microcracks, employing small angle X-ray scattering. These innovative ultrasonic and radiographic alternatives were evaluated in comparison with well-established inspection techniques. We applied thirteen different non-destructive methods to inspect the same specimen (a carbon fiber-reinforced polymer laminate with induced impact damage): air-coupled ultrasound testing (using piezoelectric transducers, broadband optical microphones, cellular polypropylene transducers, and a thermoa- coustic emitter), laser-induced ultrasound testing, ultrasonic immersion testing, phased array ultrasonic testing, optically excited lock-in thermography, and X-ray radiography (projectional absorption and dark-field, tomosynthesis, and micro-computed tomography). The inspection methods were qualitatively characterized by comparing the scan results. The conclusions are advantageous for a decision on the optimal method for certain testing constraints. KW - Carbon fiber-reinforced polymer KW - Air-coupled ultrasound KW - Optically excited lock-in thermography KW - X-ray micro-computed tomography KW - X-ray dark-field radiography PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509473 DO - https://doi.org/10.1177/0021998320931162 SN - 0021-9983 VL - 54 IS - 27 SP - 4325 EP - 4337 PB - SAGE AN - OPUS4-50947 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Li, Q. A1 - Shinde, S. A1 - Grasso, G. A1 - Caroli, A. A1 - Abouhany, R. A1 - Lanzillotta, M. A1 - Pan, G. A1 - Wan, Wei A1 - Rurack, Knut A1 - Sellergren, B. T1 - Selective detection of phospholipids using molecularly imprinted fluorescent sensory core-shell particles N2 - Sphingosine-1-phosphate (S1P) is a bioactive sphingo-lipid with a broad range of activities coupled to its role in G-protein coupled receptor signalling. Monitoring of both intra and extra cellular levels of this lipid is challenging due to its low abundance and lack of robust affinity assays or sensors. We here report on fluorescent sensory core-shell molecularly imprinted polymer (MIP) particles responsive to near physiologically relevant levels of S1P and the S1P receptor modulator fingolimod phosphate (FP) in spiked human serum samples. Imprinting was achieved using the tetrabutylammonium (TBA) salt of FP or phosphatidic acid (DPPA·Na) as templates in combination with a polymerizable nitrobenzoxadiazole (NBD)-urea monomer with the dual role of capturing the phospho-anion and signalling its presence. The monomers were grafted from ca 300 nm RAFT-modified silica core particles using ethyleneglycol dimethacrylate (EGDMA) as crosslinker resulting in 10–20 nm thick shells displaying selective fluorescence response to the targeted lipids S1P and DPPA in aqueous buffered media. Potential use of the sensory particles for monitoring S1P in serum was demonstrated on spiked serum samples, proving a linear range of 18–60 μM and a detection limit of 5.6 μM, a value in the same range as the plasma concentration of the biomarker. KW - Molecularly imprinted polymers KW - Phospholipids KW - Fluorescence KW - Dye monomers PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509485 DO - https://doi.org/10.1038/s41598-020-66802-3 SN - 2045-2322 VL - 10 IS - 1 SP - 9924 PB - Nature Research CY - London AN - OPUS4-50948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tiitta, M. A1 - Tiitta, V. A1 - Gaal, Mate A1 - Heikkinen, J. A1 - Lappalainen, R. A1 - Tomppo, L. T1 - Air-coupled ultrasound detection of natural defects in wood using ferroelectret and piezoelectric sensors N2 - Air-coupled ultrasound was used for assessing natural defects in wood boards by through-transmission scanning measurements. Gas matrix piezoelectric (GMP) and ferroelectret (FE) transducers were studied. The study also included tests with additional bias voltage with the ferroelectret receivers. Signal analyses, analyses of the measurement dynamics and statistical analyses of the signal parameters were conducted. After the measurement series, the samples were cut from the measurement regions and the defects were analyzed visually from the cross sections. The ultrasound responses were compared with the results of the visual examination of the cross sections. With the additional bias voltage, the ferroelectret measurement showed increased signal-to-noise ratio, which is especially important for air-coupled measurement of high-attenuation materials like wood. When comparing the defect response of GMP and FE sensors, it was found that FE sensors had more sensitive dynamic range, resulting from better s/n ratio and short response pulse. Classification test was made to test the possibility of detecting defects in sound wood. Machine learning methods including decision trees, k-nearest neighbor and support vector machine were used. The classification accuracy varied between 72 and 77% in the tests. All the tested machine learning methods could be used efficiently for the classification. KW - Air-coupled transducers KW - Wood KW - Ultrasound KW - Ultrasonic imaging KW - Ferroelectret KW - Machine learning PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509503 DO - https://doi.org/10.1007/s00226-020-01189-y SP - 1 EP - 14 PB - Springer AN - OPUS4-50950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strangfeld, Christoph T1 - Determination of the diffusion coefficient and the hydraulic conductivity of porous media based on embedded humidity sensors N2 - Reinforced concrete and several other building materials deteriorate during their service life. Almost all deterioration processes are related to moisture. For understanding those processes, knowing the exact amount of the moisture content and the moisture transport characteristics is crucial. In fact, the moisture transport in porous materials is a two-phase flow; consisting of the vapour and the liquid phase. The two corresponding parameters are the diffusion coefficient and the hydraulic conductivity. By means of an inverse approach, these two coefficients are experimentally determined. The moisture transport of eight different screed types during hydration and evaporation is monitored based on embedded humidity sensors. The measured humidity profiles are converted into a pore saturation by adapting the approach of Hillerborg to the measured pore volume distribution. The summation of all pore saturations yields the total moisture content including the ink-bottle effect during desorption. The pore volume distribution was determined by mercury intrusion porosimetry as well as by gas adsorption. The measurement of the humidity and the pore saturation in the entire sample enables to invert the mass balance in order to extract the diffusion coefficient and the hydraulic conductivity. The determined diffusion coefficients of the eight investigated screeds are between m2s-1 and m2s-1. KW - Material moisture KW - Moisture transport KW - Embedded sensors KW - Diffusion coefficient KW - Partially saturated pores PY - 2020 DO - https://doi.org/10.1016/j.conbuildmat.2020.120092 VL - 263 SP - 120092 PB - Elsevier Ltd. AN - OPUS4-51029 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen T1 - The Ring-Opening Polymerisation-Polycondensation (ROPPOC) Approach to cyclic Polymers N2 - A new concept called “Ring-Opening Polymerization (ROP) combined with simultaneous POlyCondensation” (ROPPOC) is presented and discussed. This synthetic strategy is based on the intermediate formation of chains having two end groups that can react with each other. The ROPPOC syntheses are subdivided into three groups according to the nature of the chain ends: two ionic end groups, one ionic and one covalent chain end and a combination of two reactive covalent end groups may be involved, depending on the catalyst. The usefulness for the preparation of cyclic polymers is discussed with a review of numerous previously published examples. These examples concern to following classes of cyclic polymers: polypeptides, polyamides, polyesters, including polycarbonates, and cyclic polysiloxanes. It is demonstrated, that the results of certain ROPPOC syntheses are in contradiction to the Jacobson-Stockmayer theory. Finally, the usefulness of ROPPOCs for the detection of polydisperse catenanes is discussed. KW - Ring-opening Polymerisation KW - MALDI-TOF MS KW - ROPPOC KW - Cyclic PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508509 DO - https://doi.org/10.1002/marc.202000152 SP - 2000152 PB - Wiley AN - OPUS4-50850 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -