Sort by
Discovery and Timing of Millisecond Pulsars in the Globular Cluster M5 with FAST and Arecibo

We report on a comprehensive multiwavelength study of the pulsars in the globular cluster (GC) M5, including the discovery of M5G, a new compact noneclipsing “black widow” pulsar. Thanks to the analysis of 34 yr of radio data taken with the Five-hundred-meter Aperture Spherical radio Telescope and Arecibo telescopes, we obtained new phase-connected timing solutions for four pulsars and improved those of the other three. These have resulted in, among other things, (a) much improved proper motions for five pulsars, with transverse velocities (relative to the cluster) that are smaller than their respective escape velocities; (b) 3σ and 1.5σ detections of Shapiro delays in M5F and M5D, respectively; and (c) greatly improved measurement of the periastron advance in M5B, whose value of implies that M5B is still likely to be a heavy () neutron star. The binary pulsars M5D, M5E, and M5F are confirmed to be in low-eccentricity binary systems, the low-mass companions of which are newly identified to be He white dwarfs using Hubble Space Telescope data. Four pulsars are also found to be associated with X-ray sources. Similarly to the eclipsing pulsar M5C, M5G shows little or no nonthermal X-ray emission, indicative of weak synchrotron radiation produced by intrabinary shocks. All seven pulsars known in M5 have short spin periods (<8 ms), and five are in binary systems with low orbital eccentricities. These characteristics differ from the overall GC pulsar population but confirm the expectations for the pulsar population in a cluster with a small rate of stellar encounters per binary system.

Open Access
Relevant
Metal organic frameworks based intelligent nanoadjuvants for boosting tumor immunotherapy through enhanced ICD and lactic acid regulation

Immunotherapy has been considered as a potent antitumor modality while its efficacy is frequently hampered by the insufficient immunogenicity and immunosuppressive tumor microenvironment (TME) with overexpressed lactic acid (LA). Herein, an intelligent nanoadjuvant MOF@LOD-siRNA@Lips-FA (MLSLF) was developed by loading lactate oxidase (LOD) and monocarboxylate transporter 4 (MCT4)-inhibiting siRNA into Fe-MOF and further coated with folate-liposomes (FA-lip) for enhanced immunotherapy. The MLSLF could response to endogenous glutathione (GSH), resulting in the depletion of GSH and production of •OH for effective chemodynamic therapy (CDT). On one hand, the death of cancer cells would arouse immunogenic cell death (ICD) to release antigens and enhance tumor immunogenicity. Meanwhile, LOD could decompose intracellular LA to H2O2, which could further promote ICD and boost anti-tumor immune response. On the other hand, the siRNA could restrict the expression of MCT4, which would hinder the intracellular LA efflux. The combination of LOD and siRNA could reduce the LA content in TME and relieve immunosuppression TME. The in vivo results revealed that MLSLF could effectually suppress the growth of primary and distant tumors in tumor-bearing mice. Therefore, the smart MLSLF could be a synergistic anti-tumor strategy for efficient immunotherapy through the combination of enhanced ICD and LA metabolism blockade.

Relevant
New SB1s with Spectroscopic Orbits from LAMOST-LRS

The LAMOST Low-Resolution Spectroscopic (LAMOST-LRS) Survey provides radial velocities of 10 million stars. These observations can be used to identify new single-lined spectroscopic binaries (SB1s) with their preliminary spectroscopic orbits. First, we perform a statistical χ 2 test on a subsample of LAMOST-LRS stars with velocity observations sufficient for the present work to obtain a set of 6852 radial velocity variables. Subsequently, we discard 399 astrophysical variables through crossmatching with variable catalogs, resulting in 1297 SB1 candidates. Finally, in order to reliably identify SB1s among these SB1 candidates, we employ a combination of The joker, rvfit, and Levenberg–Marquardt algorithms to give the best-fit solutions. An SB1 is identified if its orbital solution satisfies the criteria of the goodness-of-fit statistic (F2) < 3.1, the signal significance > 10, and the maximum gap in phase (phase_gap_max) < 0.3. Our final catalog of SB1s contains 255 systems, 168 of which are newly discovered ones. Cross validation results indicate that the determined orbital periods are consistent with periods of external catalogs within 1σ uncertainties. The period–eccentricity diagram illustrates that a majority of short-period binaries have small eccentricities. Furthermore, in comparison to the general sample, the SB1 catalog exhibits a relatively higher ratio of dwarfs than giants and a slightly lower metallicity.

Open Access
Relevant