Neutron Star vs Quark Star in the Multimessenger Era

Neutron stars (NSs) which could contain exotic degrees of freedom in the core and the self-bound quark stars (QSs) made purely of absolutely stable deconfined quark matter are still two main candidates for the compact objects observed in pulsars and gravitational wave (GW) events in binary star mergers. We perform a Bayesian model-agnostic inference of the properties of NSs and QSs by combining multi-messenger data of GW170817, GW190425, PSR J0030+0451, PSR J0740+6620, PSR J1614-2230, PSR J0348+0432 as well as ab initio calculations from perturbative quantum chromodynamics and chiral effective field theory. We find the NS scenario is strongly favored against the QS scenario with a Bayes factor of NS over QS $\mathcal{B}^\text{NS}_\text{QS} = 11.5$. In addition, the peak of the squared sound velocity $c_s^2 \sim 0.5c^2$ around $3.5$ times nuclear saturation density $n_0$ observed in the NS case disappears in the QS case which suggests that the $c_s^2$ first increases and then saturates at $c_s^2 \sim 0.5c^2$ above $\sim 4n_0$. The sound velocity and trace anomaly are found to approach the conformal limit in the core of heavy NSs with mass $M \gtrsim 2M_{\odot}$, but not in the core of QSs.Comment: 6 pages, 2 figure

MiR-489 serves as a tumor inhibitor in pituitary prolactinoma targeting p21-activated kinase 3

Purpose: To evaluate the effect of microRNA-489 (miR-489) on pituitary prolactinoma and its mechanisms of action. Methods: MMQ and GH3 cells were transfected with miR-489, cell viability assessed with cell counting kit-8 (CCK-8), and clone spots was evaluated by colony formation assay. Transwell assay was applied to measure cell migration and invasion while TargetScan was employed to the presumed targets of miR-489, followed by luciferase reporter assays. was MiR-489 and p21-activated kinase 3 (PAK3) gene expression were determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR. Protein levels of PAK3 were measured using western blots. Results: Transfection significantly increased miRNA-489 levels (p < 0.01). Cell viability, number of clone spots, as well as cell migration and invasion diminished in MMQ and GH3 cells following miR-489 transfection when compared to miR-NC mimic group (p < 0.01). The presumed binding site of miRNA- 489 was located in 3′-untranslated region (UTR) of PAK3, and miR-489 transfection repressed luciferase activity with the wild-type 3′-UTR (p < 0.05). In addition, miR-489 decreased PAK3 levels in MMQ and GH3 cells. Knockdown of PAK3 significantly suppressed cell viability, clone formation ability, as well as cell migration and invasion when compared to negative control (p < 0.01). Conclusion: MiR-489 overexpression suppresses pituitary prolactinoma by targeting PAK3, thus providing a potential therapeutic strategy for the management of pituitary prolactinoma

GW190814: Circumstantial Evidence for Up-Down Quark Star

Within a confining quark matter model which considers phenomenologically the quark confinement and asymptotic freedom as well as the chiral symmetry restoration and quark deconfinement at high baryon density, we find that if the up-down quark matter ($ud$QM) is more stable than nuclear matter and strange quark matter (SQM), the maximum mass of static quark stars with $ud$QM is $2.77M_{\odot}$ under agreement with both the constraints on star tidal deformability from gravitational wave signal GW170817 and the mass-radius of PSR J0030+045 measured simultaneously by NICER. In contrast, the conventional strange quark star with SQM has a maximum static mass of only $2.05M_{\odot}$ and its radius significantly deviates from NICER's constraint. Our results thus provide circumstantial evidence suggesting the recently reported GW190814's secondary component with a mass of $2.59^{+0.08}_{-0.09}M_\odot$ could be an up-down quark star.Comment: 5 pages, 2 figure

Non-Newtonian gravity in finite nuclei

In this talk, we report our recent study of constraining the non-Newtonian gravity at femtometer scale. We incorporate the Yukawa-type non-Newtonian gravitational potential consistently to the Skyrme functional form using the exact treatment for the direct contribution and density-matrix expansion method for the exchange contribution. The effects from the non-Newtonian potential on finite nuclei properties are then studied together with a well-tested Skyrme force. Assuming that the framework without non-Newtonian gravity can explain the binding energies and charge radii of medium to heavy nuclei within 2% error, we set an upper limit for the strength of the non-Newtonian gravitational potential at femtometer scale.Comment: Talk given at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS