Comparing charge transfer tuning effects by chemical substitution and uniaxial pressure in the organic charge transfer complex tetramethoxypyrene-tetracyanoquinodimethane

In the search for novel organic charge transfer salts with variable charge transfer degree we study the effects of two modifications to the recently synthesized donor-acceptor Tetramethoxypyrene (TMP)-Tetracyanoquinodimethane (TCNQ). One is of chemical nature by substituting the acceptor TCNQ molecules by F4TCNQ molecules. The second consists in simulating the application of uniaxial pressure along the stacking axis of the system. In order to test the chemical substitution, we have grown single crystals of TMP-F4TCNQ and analyzed its electronic structure via electronic transport measurements, ab initio density functional theory (DFT) calculations and UV/VIS/IR absorption spectroscopy. This system shows an almost ideal geometrical overlap of nearly planar molecules alternately stacked (mixed stack) and this arrangement is echoed by a semiconductor-like transport behavior with an increased conductivity along the stacking direction. This is in contrast to TMP-TCNQ which shows a less pronounced anisotropy and a smaller conductivity response. Our bandstructure calculations confirm the one-dimensional behavior of TMP-F4TCNQ with pro- nounced dispersion only along the stacking axis. Infrared measurements illustrating the CN vibration frequency shift in F4TCNQ suggest however no improvement on the degree of charge transfer in TMP-F4TCNQ with respect to TMP-TCNQ. In both complexes about 0.1 is transferred from TMP to the acceptor. Concerning the pressure effect, our DFT calculations on designed TMP-TCNQ and TMP-F4TCNQ structures under different pressure conditions show that application of uniaxial pressure along the stacking axis of TMP-TCNQ may be the route to follow in order to obtain a much more pronounced charge transfer

Effect of oxygenation process on flux pinning in pristine and BaHfO3 nanocomposite GdBa2Cu3O7 superconducting thin films

Pristine and BaHfO3 (BHO) nanocomposite GdBa2Cu3O7 (GdBCO) superconducting thin films were deposited at 800 °C, 0.4 mbar O2 partial pressure using a Nd:YAG laser (λ=355 nm) with 10 Hz frequency on MgO substrate. The influence of the oxygenation process on flux pinning and electrical transport properties was investigated by changing the annealing temperature (T ann) between 450 °C and 780 °C and the holding time (t hold) between 10 and 30 min. The irreversibility field shows the largest shift toward higher fields for T ann = 450 °C and thus the largest in-field J c. Angular dependence of J c for most of the pristine GdBCO films exhibits a large peak for B||c, however the sample with T ann = 550 °C has a large peak in the 90°-120° region, i.e. near B || ab. For BHO nanocomposites, a decrease in T ann increases in-field J c by a factor of 2

Disseminated coccidioidomycosis: Monitoring of serologic markers for treatment response

We describe a patient with a disseminated coccidioidomycosis. Biomarkers in serum during itraconazole therapy showed a rapid clearing of Coccidioides DNA as detected by PCR. Coccidioides antibody detection by lateral flow assay became negative after one year and decreased from 1:64 to 1:8 in the complement fixation test after two years. The (1 → 3)-ß-D-glucan levels normalised after two years without increase after cessation of antifungal therapy. Biomarkers in serum may guide treatment decisions in disseminated coccidioidomycosis.Peer Reviewe

Low power wind energy conversion system based on variable speed permanent magnet synchronous generators

This paper presents a low power wind energy conversion system (WECS) based on a permanent magnet synchronous generator and a high power factor (PF) rectifier. To achieve a high PF at the generator side, a power processing scheme based on a diode rectifier and a boost DC-DC converter working in discontinuous conduction mode is proposed. The proposed generator control structure is based on three cascaded control loops that regulate the generator current, the turbine speed and the amount of power that is extracted from the wind, respectively, following the turbine aerodynamics and the actual wind speed. The analysis and design of both the current and the speed loops have been carried out taking into consideration the electrical and mechanical characteristics of the WECS, as well as the turbine aerodynamics. The power loop is not a linear one, but a maximum power point tracking algorithm, based on the Perturb and Observe technique, from which is obtained the reference signal for the speed loop. Finally, to avoid the need of mechanical sensors, a linear Kalman Filter has been chosen to estimate the generator speed. Simulation and experimental results on a 2-kW prototype are shown to validate the concept. © 2013 John Wiley & Sons, Ltd.Carranza Castillo, O.; Garcerá Sanfeliú, G.; Figueres Amorós, E.; González Morales, LG. (2014). Low power wind energy conversion system based on variable speed permanent magnet synchronous generators. Wind Energy. 17(6):811-827. doi:10.1002/we.1598S811827176Ackermann, T. (Ed.). (2005). Wind Power in Power Systems. doi:10.1002/0470012684Muyeen, S. M., Shishido, S., Ali, M. H., Takahashi, R., Murata, T., & Tamura, J. (2008). Application of energy capacitor system to wind power generation. Wind Energy, 11(4), 335-350. doi:10.1002/we.265Ladenburg, J. (2009). Stated public preferences for on-land and offshore wind power generation-a review. Wind Energy, 12(2), 171-181. doi:10.1002/we.308Maeda, T., & Kamada, Y. (2009). A review of wind energy activities in Japan. Wind Energy, 12(7), 621-639. doi:10.1002/we.313Baroudi, J. A., Dinavahi, V., & Knight, A. M. (2007). A review of power converter topologies for wind generators. Renewable Energy, 32(14), 2369-2385. doi:10.1016/j.renene.2006.12.002Di Gerlando, A., Foglia, G., Iacchetti, M. F., & Perini, R. (2012). Analysis and Test of Diode Rectifier Solutions in Grid-Connected Wind Energy Conversion Systems Employing Modular Permanent-Magnet Synchronous Generators. IEEE Transactions on Industrial Electronics, 59(5), 2135-2146. doi:10.1109/tie.2011.2157295Yungtaek Jang, & Jovanovic, M. M. (2000). A new input-voltage feedforward harmonic-injection technique with nonlinear gain control for single-switch, three-phase, DCM boost rectifiers. IEEE Transactions on Power Electronics, 15(2), 268-277. doi:10.1109/63.838099Athab, H. S., Lu, D. D.-C., & Ramar, K. (2012). A Single-Switch AC/DC Flyback Converter Using a CCM/DCM Quasi-Active Power Factor Correction Front-End. IEEE Transactions on Industrial Electronics, 59(3), 1517-1526. doi:10.1109/tie.2011.2158771Barbosa, P., Canales, F., Crebier, J.-C., & Lee, F. C. (2001). Interleaved three-phase boost rectifiers operated in the discontinuous conduction mode: analysis, design considerations and experimentation. IEEE Transactions on Power Electronics, 16(5), 724-734. doi:10.1109/63.949505Yao, K., Ruan, X., Mao, X., & Ye, Z. (2011). Variable-Duty-Cycle Control to Achieve High Input Power Factor for DCM Boost PFC Converter. IEEE Transactions on Industrial Electronics, 58(5), 1856-1865. doi:10.1109/tie.2010.2052538Andriollo, M., De Bortoli, M., Martinelli, G., Morini, A., & Tortella, A. (2009). Control strategy of a wind turbine drive by an integrated model. Wind Energy, 12(1), 33-49. doi:10.1002/we.281Hansen, A. D., & Michalke, G. (2008). Modelling and control of variable-speed multi-pole permanent magnet synchronous generator wind turbine. Wind Energy, 11(5), 537-554. doi:10.1002/we.278Salvatore, N., Caponio, A., Neri, F., Stasi, S., & Cascella, G. L. (2010). Optimization of Delayed-State Kalman-Filter-Based Algorithm via Differential Evolution for Sensorless Control of Induction Motors. IEEE Transactions on Industrial Electronics, 57(1), 385-394. doi:10.1109/tie.2009.2033489Kazmi, S. M. R., Goto, H., Guo, H.-J., & Ichinokura, O. (2011). A Novel Algorithm for Fast and Efficient Speed-Sensorless Maximum Power Point Tracking in Wind Energy Conversion Systems. IEEE Transactions on Industrial Electronics, 58(1), 29-36. doi:10.1109/tie.2010.2044732Pucci, M., & Cirrincione, M. (2011). Neural MPPT Control of Wind Generators With Induction Machines Without Speed Sensors. IEEE Transactions on Industrial Electronics, 58(1), 37-47. doi:10.1109/tie.2010.2043043Ming Y Li G Ming Z Chengyong Z Modeling of the wind turbine with a permanent magnet synchronous generator for integration IEEE Power Engineering Society General Meeting, 2007 2007 1 6Carranza O Figueres E Garcera G Gonzalez LG Gonzalez-Espin F Peak current mode control of a boost rectifier with low distortion of the input current for wind power systems based on permanent magnet synchronous generators 13th European Conference on Power Electronics and Applications, EPE ’09 2009 1 10Eltamaly, A. M. (2007). Harmonics reduction of three-phase boost rectifier by modulating duty ratio. Electric Power Systems Research, 77(10), 1425-1431. doi:10.1016/j.epsr.2006.10.012Vorperian, V. (1990). Simplified analysis of PWM converters using model of PWM switch. Continuous conduction mode. IEEE Transactions on Aerospace and Electronic Systems, 26(3), 490-496. doi:10.1109/7.106126Ridley, R. B. (1991). A new, continuous-time model for current-mode control (power convertors). IEEE Transactions on Power Electronics, 6(2), 271-280. doi:10.1109/63.76813Carranza O Figueres E Garcera G Trujillo CL Velasco D Comparison of speed estimators applied to wind generation systems with noisy measurement signals ISIE 2010 IEEE International Symposium on Industrial 2010 3317 3322Yaoqin J Zhongqing Y Binggang C A new maximum power point tracking control scheme for wind generation International Conference on Power System Technology, PowerCon 2002 IEEE-PES/CSEE 2002 144 148PSIM 7.0 User's Guide (2006), Powersim Inc. 2006Carranza, O., Garcerá, G., Figueres, E., & González, L. G. (2010). Peak current mode control of three-phase boost rectifiers in discontinuous conduction mode for small wind power generators. Applied Energy, 87(8), 2728-2736. doi:10.1016/j.apenergy.2010.02.01

Identification of Ocular Autoantigens Associated With Juvenile Idiopathic Arthritis-Associated Uveitis

The purpose of the current study was to analyze the binding patterns of serum autoantibodies from juvenile idiopathic arthritis (JIA) and JIA-associated uveitis (JIAU) patients to proteomes from different ocular tissues and to identify potential ocular autoantigens in JIAU. Proteomes from porcine iris, ciliary body, or retina tissue were isolated, separated using 2D-gel electrophoresis, and transferred to a blotting membrane. The binding pattern of serum antibodies from JIA or JIAU patients or healthy controls to ocular proteins was visualized by using anti-human IgG secondary antibodies and chemiluminescence reaction. Selected protein spots were excised from silver-stained 2D gels and subjected to mass spectrometry. Serum antibodies binding to ocular proteins were detected in all patient groups and healthy controls. Irrespective of the patient groups, serum antibodies bound to 49 different protein spots of the retina proteome, to 53 of the ciliary body proteome, and to 44 of the iris proteome. The relative binding frequency of sera to these iris protein spots was significantly higher in JIAU than in JIA patients or healthy controls. Particularly in JIAU patients, cluster analyses indicated a broad range of serum antibodies directed against ocular antigens, mostly in the iris proteome. Iris proteins frequently bound by serum antibodies in all groups were identified as tubulin beta chain, vimentin, ATP synthase subunit beta, actin, and L-lactate dehydrogenase B chain. Iris proteins exclusively bound by JIAU serum antibodies were heat shock cognate 71 kDa protein and keratin. Although serum autoantibody binding to ocular antigens was not disease-specific, a significant diversity of autoantibodies against a broad range of antigens, particularly from the iris tissue, was detected in JIAU patients. As the iris is a major site of inflammation in JIAU, the present data give further evidence that autoantibodies may be involved in JIAU immunopathology

Quantum Imaging with Incoherently Scattered Light from a Free-Electron Laser

The advent of accelerator-driven free-electron lasers (FEL) has opened new avenues for high-resolution structure determination via diffraction methods that go far beyond conventional x-ray crystallography methods. These techniques rely on coherent scattering processes that require the maintenance of first-order coherence of the radiation field throughout the imaging procedure. Here we show that higher-order degrees of coherence, displayed in the intensity correlations of incoherently scattered x-rays from an FEL, can be used to image two-dimensional objects with a spatial resolution close to or even below the Abbe limit. This constitutes a new approach towards structure determination based on incoherent processes, including Compton scattering, fluorescence emission or wavefront distortions, generally considered detrimental for imaging applications. Our method is an extension of the landmark intensity correlation measurements of Hanbury Brown and Twiss to higher than second-order paving the way towards determination of structure and dynamics of matter in regimes where coherent imaging methods have intrinsic limitations

Observation of High-Energy Astrophysical Neutrinos in Three Years of IceCube Data

A search for high-energy neutrinos interacting within the IceCube detector between 2010 and 2012 provided the first evidence for a high-energy neutrino flux of extraterrestrial origin. Results from an analysis using the same methods with a third year (2012-2013) of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV - PeV range at the level of $10^{-8}\, \mathrm{GeV}\, \mathrm{cm}^{-2}\, \mathrm{s}^{-1}\, \mathrm{sr}^{-1}$ per flavor and reject a purely atmospheric explanation for the combined 3-year data at $5.7 \sigma$. The data are consistent with expectations for equal fluxes of all three neutrino flavors and with isotropic arrival directions, suggesting either numerous or spatially extended sources. The three-year dataset, with a livetime of 988 days, contains a total of 37 neutrino candidate events with deposited energies ranging from 30 to 2000 TeV. The 2000 TeV event is the highest-energy neutrino interaction ever observed.Comment: 8 pages, 5 figures. Accepted by PRL. The event catalog, event displays, and other data tables are included after the final page of the article. Changed from the initial submission to reflect referee comments, expanding the section on atmospheric backgrounds, and fixes offsets of up to 0.9 seconds in reported event times. Address correspondence to: J. Feintzeig, C. Kopper, N. Whitehor

A non-invasive online photoionization spectrometer for FLASH2

The stochastic nature of the self-amplified spontaneous emission (SASE) process of free-electron lasers (FELs) effects pulse-to-pulse fluctuations of the radiation properties, such as the photon energy, which are determinative for processes of photon-matter interactions. Hence, SASE FEL sources pose a great challenge for scientific investigations, since experimenters need to obtain precise real-time feedback of these properties for each individual photon bunch for interpretation of the experimental data. Furthermore, any device developed to deliver the according information should not significantly interfere with or degrade the FEL beam. Regarding the spectral properties, a device for online monitoring of FEL wavelengths has been developed for FLASH2, which is based on photoionization of gaseous targets and the measurements of the corresponding electron and ion time-of-flight spectra. This paper presents experimental studies and cross-calibration measurements demonstrating the viability of this online photoionization spectrometer