A Fast Radio Burst Search Method for VLBI Observation

We introduce the cross spectrum based FRB (Fast Radio Burst) search method for VLBI observation. This method optimizes the fringe fitting scheme in geodetic VLBI data post processing, which fully utilizes the cross spectrum fringe phase information and therefore maximizes the power of single pulse signals. Working with cross spectrum greatly reduces the effect of radio frequency interference (RFI) compared with using auto spectrum. Single pulse detection confidence increases by cross identifying detections from multiple baselines. By combining the power of multiple baselines, we may improve the detection sensitivity. Our method is similar to that of coherent beam forming, but without the computational expense to form a great number of beams to cover the whole field of view of our telescopes. The data processing pipeline designed for this method is easy to implement and parallelize, which can be deployed in various kinds of VLBI observations. In particular, we point out that VGOS observations are very suitable for FRB search.Comment: Accepted for publication in A

The Roles of PI3K/AKT/mTOR and MAPK/ERK Signaling Pathways in Human Pheochromocytomas

Objectives. The roles of PI3K/AKT/mTOR and MAPK/ERK pathways involved in the pathogenesis of pheochromocytoma and paraganglioma (PPGL) were demonstrated mostly by in vitro studies with rat or mouse cells and were mainly studied at transcriptional level. This study aimed to investigate the effect of these pathways on the proliferation of human PPGL cells and the activation of these pathways in PPGLs. Methods. Human PPGL cells were treated with sunitinib and inhibitors of PI3K (LY294002), MEK1/2 (U0126), and mTORC1/2 (AZD8055). Cell proliferation was detected by MTT assay. Protein phosphorylation was detected by Western blotting. Results. In most PPGLs, AKT, ERK1/2, and mTOR were activated. LY294002 (10 μM), U0126 (10 μM), AZD8055 (1 μM), and sunitinib (1 μM) inhibited PPGL cell proliferation in ten primary cultures of tissues, including four from patients with gene mutations. MEK1/2 inhibitor decreased mTOR phosphorylation. Inhibition of mTOR reduced phosphorylation of AKT and ERK1/2. Sunitinib inhibited phospho-ERK1/2 and phospho-mTOR. Conclusion. Our study suggested that PI3K/AKT/mTOR and MAPK/ERK signaling pathways play vital roles in human PPGL and are activated in most PPGLs. Inhibiting multiple pathways might be a novel therapeutic approach for PPGLs

A Search for Double-peaked narrow emission line Galaxies and AGNs in the LAMOST DR1

LAMOST has released more than two million spectra, which provide the opportunity to search for double-peaked narrow emission line (NEL) galaxies and AGNs. The double-peaked narrow-line profiles can be well modeled by two velocity components, respectively blueshifted and redshifted with respect to the systemic recession velocity. This paper presents 20 double-peaked NEL galaxies and AGNs found from LAMOST DR1 using a search method based on multi-gaussian fit of the narrow emission lines. Among them, 10 have already been published by other authors, either listed as genuine double-peaked NEL objects or as asymmetric NEL objects, the remaining 10 being first discoveries. We discuss some possible origins for double-peaked narrow-line features, as interaction between jet and narrow line regions, interaction with companion galaxies and black hole binaries. Spatially resolved optical imaging and/or follow-up observations in other spectral bands are needed to further discuss the physical mechanisms at work.Comment: 17 pages, 5figures, 4 tables, accepted by RA

The capsid protein p38 of turnip crinkle virus is associated with the suppression of cucumber mosaic virus in Arabidopsis thaliana co-infected with cucumber mosaic virus and turnip crinkle virus

AbstractInfection of plants by multiple viruses is common in nature. Cucumber mosaic virus (CMV) and Turnip crinkle virus (TCV) belong to different families, but Arabidopsis thaliana and Nicotiana benthamiana are commonly shared hosts for both viruses. In this study, we found that TCV provides effective resistance to infection by CMV in Arabidopsis plants co-infected by both viruses, and this antagonistic effect is much weaker when the two viruses are inoculated into different leaves of the same plant. However, similar antagonism is not observed in N. benthamiana plants. We further demonstrate that disrupting the RNA silencing-mediated defense of the Arabidopsis host does not affect this antagonism, but capsid protein (CP or p38)-defective mutant TCV loses the ability to repress CMV, suggesting that TCV CP plays an important role in the antagonistic effect of TCV toward CMV in Arabidopsis plants co-infected with both viruses