On the Propagation of a Geoeffective Coronal Mass Ejection during March 15 -- 17, 2015

The largest geomagnetic storm so far in the solar cycle 24 was produced by a fast coronal mass ejection (CME) originating on 2015 March 15. It was an initially west-oriented CME and expected to only cause a weak geomagnetic disturbance. Why did this CME finally cause such a large geomagnetic storm? We try to find some clues by investigating its propagation from the Sun to 1 AU. First, we reconstruct the CME's kinematic properties in the corona from the SOHO and SDO imaging data with the aid of the graduated cylindrical shell (GCS) model. It is suggested that the CME propagated to the west $\sim$$33^\circ$$\pm$$10^\circ$ away from the Sun-Earth line with a speed of about 817 km s$^{-1}$ before leaving the field of view of the SOHO/LASCO C3 camera. A magnetic cloud (MC) corresponding to this CME was measured in-situ by the Wind spacecraft two days later. By applying two MC reconstruction methods, we infer the configuration of the MC as well as some kinematic information, which implies that the CME possibly experienced an eastward deflection on its way to 1 AU. However, due to the lack of observations from the STEREO spacecraft, the CME's kinematic evolution in interplanetary space is not clear. In order to fill this gap, we utilize numerical MHD simulation, drag-based CME propagation model (DBM) and the model for CME deflection in interplanetary space (DIPS) to recover the propagation process, especially the trajectory, of the CME from $30 R_S$ to 1 AU. It is suggested that the trajectory of the CME was deflected toward the Earth by about $12^\circ$, consistent with the implication from the MC reconstruction at 1 AU. This eastward deflection probably contributed to the CME's unexpected geoeffectiveness by pushing the center of the initially west-oriented CME closer to the Earth.Comment: 10 pages, 5 figures, 1 table, accepted by JGR - Space Physic

Efficacy of repetitive transcranial magnetic stimulation at different sites for peripheral facial paralysis: a prospective cohort study

BackgroundThere are very few studies on transcranial magnetic stimulation (TMS) therapy for facial paralysis and no studies comparing the efficacy of central and peripheral TMS in the treatment of peripheral facial paralysis (PFP).PurposeTo observe the therapeutic effect and security of central and peripheral repetitive transcranial magnetic stimulation (rTMS) on PFP.MethodsPatients with unilateral onset of peripheral facial paralysis within 1 month were prospectively recruited, 97 patients with PFP were divided into the peripheral group, central group, and control group. The control group was given common treatment (drug therapy and acupuncture), and the peripheral and central groups received rTMS in addition to conventional treatment. After 2 weeks of treatment, the House-Brackmann (HB) grading scale, Sunnybrook facial grading system (SFGS), and modified Portmann scale (MPS) were used to evaluate the facial muscle function of patients in the three groups.ResultAfter 2 weeks of rTMS treatment, the HBGS/SFGS/MPS scores of the three groups were significantly better than before (p < 0.05), and the mean change values of HBGS, SFGS, and MPS scores were significantly higher in participants in Peripheral Group (p < 0.001; p < 0.001; p = 0.003; respectively) and Central Group (p = 0.004; p = 0.003; p = 0.009; respectively) than in Control Group. But the mean change values of HBGS, SFGS, and MPS scores showed no significant differences in participants in the Peripheral Group than in the Central Group (p = 0.254; p = 0.139; p = 0.736; respectively) after 2 weeks of treatment (p > 0.05).ConclusionOur study shows that rTMS can be a safe and effective adjuvant therapy for patients with PFP. Preliminary studies have shown that both peripheral and central stimulation can effectively improve facial nerve function, but there is no significant difference in the efficacy of the two sites

Profiling of mismatch discrimination in RNAi enabled rational design of allele-specific siRNAs

Silencing specificity is a critical issue in the therapeutic applications of siRNA, particularly in the treatment of single nucleotide polymorphism (SNP) diseases where discrimination against single nucleotide variation is demanded. However, no generally applicable guidelines are available for the design of such allele-specific siRNAs. In this paper, the issue was approached by using a reporter-based assay. With a panel of 20 siRNAs and 240 variously mismatched target reporters, we first demonstrated that the mismatches were discriminated in a position-dependent order, which was however independent of their sequence contexts using position 4th, 12th and 17th as examples. A general model was further built for mismatch discrimination at all positions using 230 additional reporter constructs specifically designed to contain mismatches distributed evenly along the target regions of different siRNAs. This model was successfully employed to design allele-specific siRNAs targeting disease-causing mutations of PIK3CA gene at two SNP sites. Furthermore, conformational distortion of siRNA-target duplex was observed to correlate with the compromise of gene silencing. In summary, these findings could dramatically simplify the design of allele-specific siRNAs and might also provide guide to increase the specificity of therapeutic siRNAs

Nonfragile Robust H∞ Synchronization Approach for Drive-Response Complex Dynamical Networks with Randomly Occurring Controller Gain Fluctuations and Uncertainties

This paper investigates the nonfragile H∞ synchronization problem of complex dynamical networks with randomly occurring controller gain fluctuations and uncertainties. These randomly occurring phenomena are described by independent stochastic variables satisfying Bernoulli distributions, which are adopted to model more realistic dynamical behaviors of the complex networks. By applying the Lyapunov-Krasovskii method, delay-dependent criteria are established to ensure that the synchronization can be achieved with the prescribed H∞ disturbance attenuation. Moreover, the obtained results do not rely on the derivatives of time-varying delays. A set of nonfragile controllers are further designed in terms of linear matrix inequality (LMI) approach. Finally, a numerical example is given to illustrate the effectiveness of our theoretical results

The Effects of Dimensions on the Deformation Sensing Performance of Ionic Polymer-Metal Composites

As an excellent transducer, ionic polymer-metal composites (IPMCs) can act as both an actuator and a sensor. During its sensing process, many factors, such as the water content, the cation type, the surface electrode, and the dimensions of the IPMC sample, have a considerable impact on the IPMC sensing performance. In this paper, the effect of dimensions focused on the Pd-Au typed IPMC samples with various thicknesses, widths, and lengths that were fabricated and their deformation sensing performances were tested and estimated using a self-made electromechanical sensing platform. In our experiments, we employed a two-sensing mode (both current and voltage) to record the signals generated by the IPMC bending. By comparison, it was found that the response trend was closer to the applied deformation curve using the voltage-sensing mode. The following conclusions were obtained. As the thickness increased, IPMC exhibited a better deformation-sensing performance. The thickness of the sample changed from 50 μm to 500 μm and corresponded to a voltage response signal from 0.3 to 1.6 mV. On the contrary, as the length increased, the sensing performance of IPMC decreased when subjected to equal bending. The width displayed a weaker effect on the sensing response. In order to obtain a stronger sensing response, a thickness increase, together with a length reduction, of the IPMC sample is a feasible way. Also, a simplified static model was proposed to successfully explain the sensing properties of IPMC with various sizes

Fabrication and Characterization of a Novel Smart-Polymer Actuator with Nanodispersed CNT/Pd Composite Interfacial Electrodes

As emerging smart polymers, ionic polymer-metal composites (IPMCs) are playing more and more important roles as promising candidates for next-generation actuators in terms of academic interest and industrial applications. It is reported that the actuation behaviors of IPMCs are dependent on the electrochemical kinetic process between metal/polymer interfaces to a great extent. Thus, the fabrication of tailored metal/polymer interface electrodes with large surface areas and superior interface characteristics is highly desirable in improving the actuation performance of IPMCs, which is still technologically critical for IPMCs. In this contribution, we developed a novel fabrication technology for carbon/metal composite electrodes with a superior interface structure and characteristics to optimize the actuation behaviors of IPMCs by exploiting the synergistic effect of combining a sulfonated multi-walled carbon nanotube (SCNT)/Nafion hybrid layer with nanodispersed Pd particles. The improved IPMCs showed significantly enhanced capacitance characteristics and highly facilitated charge–discharge processes. Moreover, their actuation behaviors were greatly improved as expected, including approximately 2.5 times larger displacement, 3 times faster deformation speed, 4 times greater output force, and 10 times higher volume work density compared to those of the IPMCs with traditional electrode structures. The advantages of the developed SCNT/Pd-IPMCs will greatly facilitate their applicability for artificial muscles