TY - JOUR A1 - Hennemann, Jörg A1 - Kohl, Claus-Dieter A1 - Reisert, Steffen A1 - Kirchner, Patrick A1 - Schöning, Michael Josef T1 - Copper oxide nanofibres for detection of hydrogen peroxide vapour at high concentrations JF - physica status solidi (a) N2 - We present a sensor concept based on copper(II)oxide (CuO) nanofibres for the detection of hydrogen peroxide (H2O2) vapour in the percent per volume (% v/v) range. The fibres were produced by using the electrospinning technique. To avoid water condensation in the pores, the fibres were initially modified by an exposure to H2S to get an enclosed surface. By a thermal treatment at 350 °C the fibres were oxidised back to CuO. Thereby, the visible pores disappear which was verified by SEM analysis. The fibres show a decrease of resistance with increasing H2O2 concentration which is due to the fact that hydrogen peroxide is an oxidising gas and CuO a p-type semiconductor. The sensor shows a change of resistance within the minute range to the exposure until the maximum concentration of 6.9% v/v H2O2. At operating temperatures below 450 °C the corresponding sensor response to a concentration of 4.1% v/v increases. The sensor shows a good reproducibility of the signal at different measurements. CuO seems to be a suitable candidate for the detection of H2O2 vapour at high concentrations. Resistance behaviour of the sensor under exposure to H2O2 vapours between 2.3 and 6.9% v/v at an operating temperature of 450 °C. Y1 - 2013 U6 - http://dx.doi.org/10.1002/pssa.201200775 SN - 1862-6319 VL - 210 IS - 5 SP - 859 EP - 863 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Murib, M. S. A1 - Grinsven, B. van A1 - Grieten, L. A1 - Janssens, S. D. A1 - Vermeeren, V. A1 - Eersels, K. A1 - Broeders, J. A1 - Ameloot, M. A1 - Michiels, L. A1 - Ceuninck, W. De A1 - Haenen, K. A1 - Schöning, Michael Josef A1 - Wagner, Patrick T1 - Electronic monitoring of chemical DNA denaturation on nanocrystalline diamond electrodes with different molarities and flow rates JF - Physica Status Solidi (A). Vol. 210 (2013), iss. 5 Y1 - 2013 SN - 0031-8965 SP - 911 EP - 917 PB - Wiley-VCH CY - Berlin ER - TY - JOUR A1 - Hegger, Josef A1 - Claßen, Martin A1 - Schaumann, Peter A1 - Sothmann, Jörg A1 - Feldmann, Markus A1 - Döring, Bernd T1 - Entwicklung einer integrierten Verbunddecke für nachhaltige Stahlbauten JF - Stahlbau Y1 - 2013 SN - 1437-1049 (E-Journal); 0038-9145 (Print) VL - Vol. 82 IS - Iss. 1 SP - 11 EP - 17 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Tippkötter, Nils A1 - Al-Kaidy, Huschyar A1 - Wollny, Steffen A1 - Ulber, Roland T1 - Functionalized magnetizable particles for downstream processing in single-use systems JF - Chemie Ingenieur Technik N2 - Biotechnological downstream processing is usually an elaborate procedure, requiring a multitude of unit operations to isolate the target component. Besides the disadvantageous space-time yield, the risks of cross-contaminations and product loss grow fast with the complexity of the isolation procedure. A significant reduction of unit operations can be achieved by application of magnetic particles, especially if these are functionalized with affinity ligands. As magnetic susceptible materials are highly uncommon in biotechnological processes, target binding and selective separation of such particles from fermentation or reactions broths can be done in a single step. Since the magnetizable particles can be produced from iron salts and low priced polymers, a single-use implementation of these systems is highly conceivable. In this article, the principles of magnetizable particles, their synthesis and functionalization are explained. Furthermore, applications in the area of reaction engineering, microfluidics and downstream processing are discussed focusing on established single-use technologies and development potential. Y1 - 2013 U6 - http://dx.doi.org/10.1002/cite.201200130 VL - 85 IS - 1-2: Special Issue: Single-Use Technology SP - 76 EP - 86 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Schusser, Sebastian A1 - Leinhos, Marcel A1 - Bäcker, Matthias A1 - Poghossian, Arshak A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Impedance spectroscopy: A tool for real-time in situ monitoring of the degradation of biopolymers JF - Physica Status Solidi (A) N2 - Investigation of the degradation kinetics of biodegradable polymers is essential for the development of implantable biomedical devices with predicted biodegradability. In this work, an impedimetric sensor has been applied for real-time and in situ monitoring of degradation processes of biopolymers. The sensor consists of two platinum thin-film electrodes covered by a polymer film to be studied. The benchmark biomedical polymer poly(D,L-lactic acid) (PDLLA) was used as a model system. PDLLA films were deposited on the sensor structure from a polymer solution by using the spin-coating method. The degradation kinetics of PDLLA films have been studied in alkaline solutions of pH 9 and 12 by means of an impedance spectroscopy (IS) method. Any changes in a polymer capacitance/resistance induced by water uptake and/or polymer degradation will modulate the global impedance of the polymer-covered sensor that can be used as an indicator of the polymer degradation. The degradation rate can be evaluated from the time-dependent impedance spectra. As expected, a faster degradation has been observed for PDLLA films exposed to pH 12 solution. Y1 - 2013 U6 - http://dx.doi.org/10.1002/pssa.201200941 SN - 1521-396X ; 0031-8965 VL - 210 IS - 5 SP - 905 EP - 910 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Martinez, Ronny A1 - Jakob, Felix A1 - Tu, Ran A1 - Siegert, Petra A1 - Maurer, Karl-Heinz A1 - Schwaneberg, Ulrich T1 - Increasing activity and thermal resistance of Bacillus gibsonii alkaline protease (BgAP) by directed evolution JF - Biotechnology and bioengineering Y1 - 2013 SN - 1097-0290 (E-Journal); 0006-3592 (Print); 0368-1467 (Print) VL - Vol. 110 IS - Iss. 3 SP - 711 EP - 720 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Orzada, Stephan A1 - Johst, Sören A1 - Maderwald, Stefan A1 - Bitz, Andreas A1 - Solbach, Klaus A1 - Ladd, Mark E. T1 - Mitigation of B1(+) inhomogeneity on single-channel transmit systems with TIAMO JF - Magnetic Resonance in Medicine Y1 - 2013 U6 - http://dx.doi.org/10.1002/mrm.24453 SN - 1522-2594 VL - 70 IS - 1 SP - 290 EP - 294 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Kraff, Oliver A1 - Wrede, Karsten H. A1 - Schoemberg, Tobias A1 - Dammann, Philipp A1 - Noureddine, Yacine A1 - Orzada, Stephan A1 - Ladd, Mark E. A1 - Bitz, Andreas T1 - MR safety assessment of potential RF heating from cranial fixation plates at 7 T JF - Medical Physics Y1 - 2013 U6 - http://dx.doi.org/10.1118/1.4795347 SN - 2473-4209 VL - 40 IS - 4 SP - 042302-1 EP - 042302-10 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Reisert, Steffen A1 - Schneider, Benno A1 - Geissler, Hanno A1 - Gompel, Matthias van A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Multi-sensor chip for the investigation of different types of metal oxides for the detection of H2O2 in the ppm range JF - physica status solidi (a) N2 - In this work, a multi-sensor chip for the investigation of the sensing properties of different types of metal oxides towards hydrogen peroxide in the ppm range is presented. The fabrication process and physical characterization of the multi-sensor chip are described. Pure SnO2 and WO3 as well as Pd- and Pt-doped SnO2 films are characterized in terms of their sensitivity to H2O2. The sensing films have been prepared by drop-coating of water-dispensed nano-powders. A physical characterization, including scanning electron microscopy and X-ray diffraction analysis of the deposited metal-oxide films, was done. From the measurements in hydrogen peroxide atmosphere, it could be shown, that all of the tested metal oxide films are suitable for the detection of H2O2 in the ppm range. The highest sensitivity and reproducibility was achieved using Pt-doped SnO2. Calibration plot of a SnO2, WO3, Pt-, and Pd-doped SnO2 gas sensor for H2O2 concentrations in the ppm range. Y1 - 2013 SN - 1862-6319 VL - 210 IS - 5 SP - 898 EP - 904 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Thiel, Alexander A1 - Tippkötter, Nils A1 - Suck, Kirstin A1 - Sohling, Ulrich A1 - Ruf, Friedrich A1 - Ulber, Roland T1 - New zeolite adsorbents for downstream processing of polyphenols from renewable resources JF - Engineering in Life Sciences N2 - Commercial materials with polyvinylpolypyrrolidone and polymeric amberlites (XAD7HP, XAD16) are commonly used for the adsorptive downstream processing of polyphenols from renewable resources. In this study, beta-zeolite-based adsorbent systems were examined, and their properties were compared to organic resins. Batch adsorption experiments were conducted with synthetic solutions of major polyphenols. Adsorption isotherms and desorption characteristics of individual adsorbent were determined based on these results. Maximum adsorption capacities were calculated using the Langmuir model. For example, the zeolites had capacities up to 203.2 mg/g for ferulic acid. To extend these results to a complex system, additional experiments were performed on rapeseed meal and wheat seed extracts as representative renewable resources. HPLC analysis showed that with 7.5% w/v, which is regarded as the optimum amount of zeolites, zeolites A and B could bind 100% of the major polyphenols as well as release polyphenols at high yields. Additionally, regeneration experiments were performed with isopropyl alcohol at 99°C to evaluate how zeolites regenerate under mild conditions. The results showed only a negligible loss of adsorption capacity and no loss of desorption capacity. In summary, it was concluded that beta-zeolites were promising adsorbents for developing new processes to isolate polyphenols from renewable resources. Y1 - 2013 U6 - http://dx.doi.org/10.1002/elsc.201200188 VL - 13 IS - 3 SP - 239 EP - 246 PB - Wiley CY - Weinheim ER -