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A low-energy ion spectrometer (LEIS) for use aboard three-axis stabilized spacecraft has been developed to measure ion energy per charge distribution in three-dimensional space with good energy-, angular- and temporal-resolutions. For the standard top-hat electrostatic analyzer used widely in space plasma detection, three-axis stabilized spacecraft makes it difficult to obtain complete coverage of all possible ion arrival directions. We have designed angular scanning deflectors supplementing to a cylindrically symmetric top-hat electrostatic analyzer to provide a half-space field of view as 360°×90° (–45°–+45°), and fabricated the LEIS flight model for detecting magnetospheric ions in geosynchronous orbit. The performance of this payload has been evaluated in detail by a series of simulation and environmental tests, and the payload has also been calibrated through laboratory experiments using a low-energy ion source. The results show that capabilities of the LEIS payload are in accordance with the requirements of a magnetospheric mission.

We establish a catalog of interplanetary coronal mass ejections (ICMEs) during the period from 1995 to 2015 using the in-situ observations from the Wind and ACE spacecraft. Based on this catalog, we extend the statistical properties of ICMEs to the maximum phase of Solar Cycle 24. We confirm previous results that the yearly occurrence frequencies of ICMEs and shocks, the ratios of ICMEs driving shocks are correlated with the sunspot numbers. For the magnetic cloud (MC), we confirm that the yearly occurrence frequencies of MCs do not show any correlation with sunspot numbers. The highest MC ratio of ICME occurred near the solar minimum. In addition, we analyzed the yearly variation of the ICME parameters. We found that the ICME velocities, the magnetic-field strength, and their related parameters are varied in pace with solar-cycle variation. At the solar maximum, ICMEs move faster and carry a stronger magnetic field. By comparing the parameters between MCs and non-MC ejecta, we confirm the result that the magnetic-field intensities of MC are higher than those in non-MC ejecta. Furthermore, we also discuss the forward shocks driven by ICMEs. We find that one half of the ICMEs have upstream shocks and ICMEs with shocks have faster speed and higher magnetic-field strength than the ICMEs without shocks. The magnetic-field parameters and solar-wind plasma parameters in the shock sheath regions are higher than those in the ejecta regions of ICMEs from a statistical point of view.

Observational and numerical studies have shown that the kinematic characteristics of two or more coronal mass ejections (CMEs) may change significantly after a CME collision. The collision of CMEs can have a different nature, i.e. inelastic, elastic, and superelastic processes, depending on their initial kinematic characteristics. In this article, we first review the existing definitions of collision types including Newton’s classical definition, the energy definition, Poisson’s definition, and Stronge’s definition, of which the first two were used in the studies of CME–CME collisions. Then, we review the recent research progresses on the nature of CME–CME collisions with the focus on which CME kinematic properties affect the collision nature. It is shown that observational analysis and numerical simulations can both yield an inelastic, perfectly inelastic, merging-like collision, or a high possibility of a superelastic collision. Meanwhile, previous studies based on a 3D collision picture suggested that a low approaching speed of two CMEs is favorable for a superelastic nature. Since CMEs are an expanding magnetized plasma structure, the CME collision process is quite complex, and we discuss this complexity. Moreover, the models used in both observational and numerical studies contain many limitations. All of the previous studies on collisions have not shown the separation of two colliding CMEs after a collision. Therefore the collision between CMEs cannot be considered as an ideal process in the context of a classical Newtonian definition. In addition, many factors are not considered in either observational analysis or numerical studies, e.g. CME-driven shocks and magnetic reconnections. Owing to the complexity of the CME collision process, a more detailed and in-depth observational analysis and simulation work are needed to fully understand the CME collision process.

Emerging evidence has shown that single nucleotide polymorphisms occurred in microRNAs may contribute to the development of colorectal cancer (CRC). rs2910164 in miR-146a and rs11614913 in miR-196a2 are suggested to be associated with the susceptibility to CRC, but individually published studies revealed inconclusive results. To systematically summarize the possible correlationship between these polymorphisms and CRC risk, we performed this meta-analysis.We retrieved the relevant articles of the associations between these two microRNA polymorphisms and susceptibility to CRC for the period up to July 1, 2013. A total of seven articles were identified with 2,143 cases and 2,457 controls for miR-146a rs2910164, 1,594 cases and 2,252 controls for miR-196a2 rs11614913. Odds ratio and 95 % confidence interval were calculated to investigate the strength of the association.The pooled analysis showed that miR-146a rs2910164 did not reveal any correlation with CRC susceptibility. However, a decreased risk was observed between miR-196a2 rs11614913 and CRC in all genetic models.Our current meta-analysis demonstrates that miR-196a2 rs11614913 most likely contributes to decreased risk of CRC, whereas miR-146a rs2910164 may not be associated with the susceptibility to CRC.

A super-elastic collision is an unusual process in which some mechanism causes the kinetic energy of the system to increase. Most studies have focused on solid-like objects, and have rarely considered gases or liquids, as the collision of these is primarily a mixing process. However, magnetized plasmoids are different from ordinary gases—as cross-field diffusion is effectively prohibited—but it remains unclear how they behave during a collision. Here we present a comprehensive picture of a unique collision between two coronal mass ejections in the heliosphere, which are the largest magnetized plasmoids erupting from the Sun. Our analysis reveals that these two magnetized plasmoids collided as if they were solid-like objects, with a likelihood of 73% that the collision was super-elastic. The total kinetic energy of the plasmoid system increased by about 6.6% through the collision, significantly influencing its dynamics. A super-elastic collision is one that results in an increase of kinetic energy in the colliding system. A probable occurrence of such a collision is shown in the huge, magnetized plasmas of two coronal mass ejections from the Sun.

A solar coronal mass ejection (CME) is a large-scale eruption of plasma and magnetic fields from the Sun. It is believed to be the main source of strong interplanetary disturbances that may cause intense geomagnetic storms. However, not all front-side halo CMEs can encounter the Earth and produce geomagnetic storms. The longitude distribution of the Earth-encountered front-side halo CMEs (EFHCMEs) has not only an east–west (E–W) asymmetry (Wang et al., 2002), but also depends on the EFHCMEs' transit speeds from the Sun to 1 AU. The faster the EFHCMEs are, the more westward does their distribution shift, and as a whole, the distribution shifts to the west. Combining the observational results and a simple kinetic analysis, we believe that such E–W asymmetry appearing in the source longitude distribution is due to the deflection of CMEs' propagation in the interplanetary medium. Under the effect of the Parker spiral magnetic field, a fast CME will be blocked by the background solar wind ahead and deflected to the east, whereas a slow CME will be pushed by the following background solar wind and deflected to the west. The deflection angle may be estimated according to the CMEs' transit speed by using a kinetic model. It is shown that slow CMEs can be deflected more easily than fast ones. This is consistent with the observational results obtained by Zhang et al. (2003), that all four Earth-encountered limb CMEs originated from the east. On the other hand, since the most of the EFHCMEs are fast events, the range of the longitude distribution given by the theoretical model is E40°,W70°, which is well consistent with the observational results (E40°,W75°).