TY - JOUR A1 - Alebouyeh Samami, Behzad A1 - Pieper, Martin A1 - Breitbach, Gerd A1 - Hodapp, Josef T1 - Heat production in the windings of the stators of electric machines under stationary condition JF - Heat and mass transfer N2 - In electric machines due to high currents and resistive losses (joule heating) heat is produced. To avoid damages by overheating the design of effective cooling systems is required. Therefore the knowledge of heat sources and heat transfer processes is necessary. The purpose of this paper is to illustrate a good and effective calculation method for the temperature analysis based on homogenization techniques. These methods have been applied for the stator windings in a slot of an electric machine consisting of copper wires and resin. The key quantity here is an effective thermal conductivity, which characterizes the heterogeneous wire resin-arrangement inside the stator slot. To illustrate the applicability of the method, the analysis of a simplified, homogenized model is compared with the detailed analysis of temperature behavior inside a slot of an electric machine according to the heat generation. We considered here only the stationary situation. The achieved numerical results are accurate and show that the applied homogenization technique works in practice. Finally the results of simulations for the two cases, the original model of the slot and the homogenized model chosen for the slot (unit cell), are compared to experimental results. Y1 - 2014 U6 - http://dx.doi.org/10.1007/s00231-014-1371-8 SN - 0947-7411 (Print) ; 1432-1181 (E-Journal) VL - 50 SP - 1707 EP - 1716 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Heine, A. A1 - Herrmann, G. A1 - Selmer, Thorsten A1 - Terwesten, F. A1 - Buckel, W. A1 - Reuter, K. T1 - High resolution crystal structure of clostridium propionicum β-Alanyl-CoA:Ammonia Lyase, a new member of the "Hot Dog Fold" protein superfamily JF - Proteins N2 - Clostridium propionicum is the only organism known to ferment β-alanine, a constituent of coenzyme A (CoA) and the phosphopantetheinyl prosthetic group of holo-acyl carrier protein. The first step in the fermentation is a CoA-transfer to β-alanine. Subsequently, the resulting β-alanyl-CoA is deaminated by the enzyme β-alanyl-CoA:ammonia lyase (Acl) to reversibly form ammonia and acrylyl-CoA. We have determined the crystal structure of Acl in its apo-form at a resolution of 0.97 Å as well as in complex with CoA at a resolution of 1.59 Å. The structures reveal that the enyzme belongs to a superfamily of proteins exhibiting a so called “hot dog fold” which is characterized by a five-stranded antiparallel β-sheet with a long α-helix packed against it. The functional unit of all “hot dog fold” proteins is a homodimer containing two equivalent substrate binding sites which are established by the dimer interface. In the case of Acl, three functional dimers combine to a homohexamer strongly resembling the homohexamer formed by YciA-like acyl-CoA thioesterases. Here, we propose an enzymatic mechanism based on the crystal structure of the Acl·CoA complex and molecular docking. Proteins 2014; 82:2041–2053. © 2014 Wiley Periodicals, Inc. Y1 - 2014 U6 - http://dx.doi.org/10.1002/prot.24557 SN - 1097-0134 (E-Journal); 0887-3585 (Print) VL - 82 IS - 9 SP - 2041 EP - 2053 PB - Wiley-Liss CY - New York ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Itabashi, Akinori A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - High-speed chemical imaging inside a microfluidic channel JF - Sensors and actuators. B: Chemical N2 - In this study, a high-speed chemical imaging system was developed for visualization of the interior of a microfluidic channel. A microfluidic channel was constructed on the sensor surface of the light-addressable potentiometric sensor (LAPS), on which the ion concentrations could be measured in parallel at up to 64 points illuminated by optical fibers. The temporal change of pH distribution inside the microfluidic channel was recorded at a maximum rate of 100 frames per second (fps). The high frame rate allowed visualization of moving interfaces and plugs in the channel even at a flow velocity of 111 mm/s, which suggests the feasibility of plug-based microfluidic devices for flow-injection analysis (FIA). Y1 - 2014 U6 - http://dx.doi.org/10.1016/j.snb.2013.12.090 SN - 1873-3077 (E-Journal); 0925-4005 (Print) VL - 194 SP - 521 EP - 527 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kronhardt, Valentina A1 - Alexopoulos, Spiros A1 - Reißel, Martin A1 - Sattler, Johannes, Christoph A1 - Hoffschmidt, Bernhard A1 - Hänel, Matthias A1 - Doerbeck, Till T1 - High-temperature thermal storage system for solar tower power plants with open-volumetric air receiver simulation and energy balancing of a discretized model JF - Energy procedia N2 - This paper describes the modeling of a high-temperature storage system for an existing solar tower power plant with open volumetric receiver technology, which uses air as heat transfer medium (HTF). The storage system model has been developed in the simulation environment Matlab/Simulink®. The storage type under investigation is a packed bed thermal energy storage system which has the characteristics of a regenerator. Thermal energy can be stored and discharged as required via the HTF air. The air mass flow distribution is controlled by valves, and the mass flow by two blowers. The thermal storage operation strategy has a direct and significant impact on the energetic and economic efficiency of the solar tower power plants. Y1 - 2014 U6 - http://dx.doi.org/10.1016/j.egypro.2014.03.094 SN - 1876-6102 (E-Journal) ; 1876-6102 (Print) VL - 49 SP - 870 EP - 877 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Schirra, Julian A1 - Watmuff, Jonathan A1 - Bauschat, J.-Michael T1 - Highly non-planar lifting systems: a relative assessment of existing potential-methodologies to accurately estimate the induced drag JF - 32nd AIAA Applied Aerodynamics Conference 2014 : June, 16-20 2014, Atlanta, Ga. Y1 - 2014 SN - 978-1-62410-288-2 U6 - http://dx.doi.org/10.2514/6.2014-2988 SP - Publ. online ER - TY - CHAP A1 - Rousseau, Alain A1 - Kern, Alexander T1 - How to deal with environmental risk in IEC 62305-2 T2 - 2014 International Conference on Lightning Protection (ICLP), Shanghai, China N2 - The 2nd edition of the lightning risk management standard (IEC 62305-2) considers structures, which may endanger environment. In these cases, the loss is not limited to the structure itself, which is valid for usual structures. In the past (Edition 1) this danger was simply taken into account by a special hazard factor, multiplying the existing risk for the structure with a number. Now, in the edition 2, we add to the risk for the structure itself a “second risk” due to the losses outside the structure. The losses outside can be treated independently from what occurs inside. This is a major advantage to analyze the risk for sensitive structures, like chemical plants, nuclear plants, or structures containing explosives, etc. In this paper, the existing procedure given by the European version EN 62305-2 Ed.2 is further developed and applied to a few structures. Y1 - 2014 SP - 521 EP - 527 ER - TY - JOUR A1 - Whitehead, Mark A1 - Öhlschläger, Peter A1 - Almajhdi, Fahad N. A1 - Alloza, Leonor A1 - Marzábal, Pablo A1 - Meyers, Ann E. A1 - Hitzeroth, Inga I. A1 - Rybicki, Edward P. T1 - Human papillomavirus (HPV) type 16 E7 protein bodies cause tumour regression in mice JF - BMC cancer Y1 - 2014 U6 - http://dx.doi.org/10.1186/1471-2407-14-367 SN - 1471-2407 IS - 14:367 SP - 1 EP - 15 PB - BioMed Central CY - London ER - TY - JOUR A1 - Dachwald, Bernd A1 - Mikucki, Jill A1 - Tulaczyk, Slawek A1 - Digel, Ilya A1 - Espe, Clemens A1 - Feldmann, Marco A1 - Francke, Gero A1 - Kowalski, Julia A1 - Xu, Changsheng T1 - IceMole : A maneuverable probe for clean in situ analysis and sampling of subsurface ice and subglacial aquatic ecosystems JF - Annals of Glaciology N2 - There is significant interest in sampling subglacial environments for geobiological studies, but they are difficult to access. Existing ice-drilling technologies make it cumbersome to maintain microbiologically clean access for sample acquisition and environmental stewardship of potentially fragile subglacial aquatic ecosystems. The IceMole is a maneuverable subsurface ice probe for clean in situ analysis and sampling of glacial ice and subglacial materials. The design is based on the novel concept of combining melting and mechanical propulsion. It can change melting direction by differential heating of the melting head and optional side-wall heaters. The first two prototypes were successfully tested between 2010 and 2012 on glaciers in Switzerland and Iceland. They demonstrated downward, horizontal and upward melting, as well as curve driving and dirt layer penetration. A more advanced probe is currently under development as part of the Enceladus Explorer (EnEx) project. It offers systems for obstacle avoidance, target detection, and navigation in ice. For the EnEx-IceMole, we will pay particular attention to clean protocols for the sampling of subglacial materials for biogeochemical analysis. We plan to use this probe for clean access into a unique subglacial aquatic environment at Blood Falls, Antarctica, with return of a subglacial brine sample. KW - Antarctic Glaciology KW - Extraterrestrial Glaciology KW - Glaciological instruments and methods KW - Subclacial exploration KW - Subglacial lakes Y1 - 2014 U6 - http://dx.doi.org/10.3189/2014AoG65A004 SN - 1727-5644 VL - 55 IS - 65 SP - 14 EP - 22 PB - Cambridge University Press CY - Cambridge ER - TY - JOUR A1 - Vos, E. K. A1 - Lagemaat, M. W. A1 - Barentsz, J. O. A1 - Fütterer, J. J. A1 - Zamecnik, P. A1 - Roozen, H. A1 - Orzada, S. A1 - Bitz, Andreas A1 - Maas, M. C. A1 - Scheenen, T. W. J. T1 - Image quality and cancer visibility of T2-weighted Magnetic Resonance Imaging of the prostate at 7 Tesla JF - European Radiology N2 - Objectives To assess the image quality of T2-weighted (T2w) magnetic resonance imaging of the prostate and the visibility of prostate cancer at 7 Tesla (T). Materials & methods Seventeen prostate cancer patients underwent T2w imaging at 7T with only an external transmit/receive array coil. Three radiologists independently scored images for image quality, visibility of anatomical structures, and presence of artefacts. Krippendorff’s alpha and weighted kappa statistics were used to assess inter-observer agreement. Visibility of prostate cancer lesions was assessed by directly linking the T2w images to the confirmed location of prostate cancer on histopathology. Results T2w imaging at 7T was achievable with ‘satisfactory’ (3/5) to ‘good’ (4/5) quality. Visibility of anatomical structures was predominantly scored as ‘satisfactory’ (3/5) and ‘good’ (4/5). If artefacts were present, they were mostly motion artefacts and, to a lesser extent, aliasing artefacts and noise. Krippendorff’s analysis revealed an α = 0.44 between three readers for the overall image quality scores. Clinically significant cancer lesions in both peripheral zone and transition zone were visible at 7T. Conclusion T2w imaging with satisfactory to good quality can be routinely acquired, and cancer lesions were visible in patients with prostate cancer at 7T using only an external transmit/receive body array coil. Y1 - 2014 U6 - http://dx.doi.org/10.1007/s00330-014-3234-6 SN - 1432-1084 VL - 24 IS - 8 SP - 1950 EP - 1958 PB - Springer CY - Cham ER - TY - JOUR A1 - Riedel, Marc A1 - Kartchemnik, Julia A1 - Schöning, Michael Josef A1 - Lisdat, Fred T1 - Impedimetric DNA detection – steps forward to sensorial application JF - Analytical chemistry N2 - This study describes a label-free impedimetric sensor based on short ssDNA recognition elements for the detection of hybridization events. We concentrate on the elucidation of the influence of target length and recognition sequence position on the sensorial performance. The impedimetric measurements are performed in the presence of the redox system ferri-/ferrocyanide and show an increase in charge transfer resistance upon hybridization of ssDNA to the sensor surface. Investigations on the impedimetric signal stability demonstrate a clear influence of the buffers used during the sensor preparation and the choice of the passivating mercaptoalcanol compound. A stable sensor system has been developed, enabling a reproducible detection of 25mer target DNA in the low nanomolar range. After hybridization, a sensor regeneration can be reached with deionized water by adjustment of effective convection conditions, ensuring a sensor reusability. By investigations of longer targets with overhangs exposed to the solution, we can demonstrate applicability of the impedimetric detection for longer ssDNA. However, a decreasing charge transfer resistance change (ΔRct) is found by extending the overhang. As a strategy to increase the impedance change for longer target strands, the position of the recognition sequence can be designed in a way that a small overhang is exposed to the electrode surface. This is found to result in an increase in the relative Rct change. These results suggest that DNA and consequently negative charge near the electrode possess a larger impact on the impedimetric signal than DNA further away. Y1 - 2014 U6 - http://dx.doi.org/10.1021/ac501800q SN - 1520-6882 (E-Journal); 0003-2700 (Print); 0096-4484 (Print) VL - 86 (2014) IS - 15 SP - 7867 EP - 7874 PB - ACS Publications CY - Columbus ER -