The post-merger product of the first binary neutron star merger event detected in gravitational waves, GW170817, depends on neutron star equation of state (EoS) and is not well determined. We ...generally discuss the constraints one may pose on the maximum mass of a non-spinning neutron star, MTOV, based on the observations and some EoS-independent universal relations of rapidly spinning neutron stars. If the merger product is a black hole after a brief hypermassive neutron star (HMNS) phase, we derive at the 2 (1 ) level. The cases for a massive neutron star (MNS), neither a supramassive neutron star (SMNS) nor even a stable neutron star (SNS) are also allowed by the data. We derive for the SMNS case and for the SNS case, at the 2 (1 ) confidence level. In the MNS cases, we also discuss the constraints on the neutron star parameters (the dipolar magnetic field strength at the surface Bp and the ellipticity ) that affect the spin down history, by considering different MNS survival times, e.g., 300 s, 1 day, and 155 days after the merger, as suggested by various observational arguments. We find that once an SMNS is formed, without violating the electromagnetic observational constraints, there always exist a set of ( ) parameters that allow the SMNS to survive for 300 s, 1 day, 155 days, or even longer.
Abstract
GRB 221009A is a bright gamma-ray burst (GRB) with isotropic energy larger than 10
54
erg. Its fairly low redshift makes it a promising candidate for high-energy neutrino detection. However, ...a neutrino search for this GRB reported by the IceCube collaboration yielded a null result. In this paper, we utilize the upper limit from the IceCube observation to test different GRB prompt emission models. We find that, at least for this specific burst, the dissipative photosphere model could be ruled out in a large parameter space. The internal-shock model can survive only with a large bulk motion Lorentz factor Γ, where the most stringent and conservative constraints are Γ > ∼ 450 and Γ > ∼ 200, respectively. Also, the ratio of the total dissipated energy that goes into the protons and electrons (
ϵ
p
/
ϵ
e
) can be constrained with a given Γ. For Γ < 400,
ϵ
p
/
ϵ
e
< 10 is required. For the Internal-collision-induced Magnetic Reconnection and Turbulence (ICMART) model, the constraint from GRB 221009A is modest. Under the ICMART model, only for extreme situations when most dissipated energy deposit into protons and all accelerated protons are suitable for producing neutrinos, a slightly large bulk motion (Γ > ∼ 250) is required.
Nanocatalytic medicine has emerged as a promising method for the specific cancer therapy by mediating the interaction between tumor microenvironment biomarkers and nanoagents. However, the produced ...antitumor cell killing molecules, such as reactive oxygen species (ROS), by catalysis are insufficient to inhibit tumor growth. Herein, a novel kind of polyvinyl pyrrolidone modified multifunctional iron sulfide nanoparticles (Fe1−xS‐PVP NPs) is developed via a one‐step hydrothermal method, which exhibits high photothermal (PT) conversion efficiency (η = 24%) under the irradiation of 808 nm near‐infrared laser. The increased temperature further facilitates the Fenton reaction to generate abundant •OH radicals. More importantly, under an acidic (pH = 6.5) condition within tumor environment, the Fe1−xS‐PVP NPs can in situ produce H2S gas, which is evidenced to suppress the activity of enzyme cytochrome c oxidase (COX IV) in cancer cells, contributing to inhibit the growth of tumor. Both in vitro and in vivo results demonstrate that the H2S‐mediated gas therapy in combination with PT enhanced ROS achieves excellent antitumor performance, which can open up a new approach for the design of gas‐mediated cancer treatment.
Based on nanocatalytic medicine, a novel strategy to combine H2S‐mediated gas therapy with photothermal enhanced reactive oxygen species via a facile but multifunctional nanoagent (Fe1−xS‐PVP NPs) is developed to achieve excellent antitumor performance. Additionally, H2S‐mediated gas therapy is beneficial to suppress the activity of enzyme cytochrome c oxidase and further inhibit cellular aerobic respiration and the decreased production of ATP.
Due to the limited sensitivity of the current gravitational wave (GW) detectors, the central remnant of the binary neutron star (NS) merger associated with GW170817 remains an open question. In view ...of the relatively large total mass, it is generally proposed that the merger of GW170817 would lead to a short-lived hypermassive NS or directly produce a black hole (BH). There is no clear evidence to support or rule out a long-lived NS as the merger remnant. Here, we utilize the GW and electromagnetic (EM) signals to comprehensively investigate the parameter space that allows a long-lived NS to survive as the merger remnant of GW170817. We find that for some stiff equations of state, the merger of GW170817 could, in principle, lead to a massive NS, which has a millisecond spin period. The post-merger GW signal could hardly constrain the ellipticity of the NS. If the ellipticity reaches 10−3, in order to be compatible with the multi-band EM observations, the dipole magnetic field of the NS (Bp) is constrained to the magnetar level of ∼1014 G. If the ellipticity is smaller than 10−4, Bp is constrained to the level of ∼109-1011 G. These conclusions weakly depend on the adoption of the NS equation of state.
Pancreatic cancer is one of the most lethal malignancies worldwide. Although the standard of care in pancreatic cancer has improved, prognoses for patients remain poor with a 5-year survival rate of ...< 5%. Angiogenesis, namely, the formation of new blood vessels from pre-existing vessels, is an important event in tumor growth and hematogenous metastasis. It is a dynamic and complex process involving multiple mechanisms and is regulated by various molecules. Inhibition of angiogenesis has been an established therapeutic strategy for many solid tumors. However, clinical outcomes are far from satisfying for pancreatic cancer patients receiving anti-angiogenic therapies. In this review, we summarize the current status of angiogenesis in pancreatic cancer research and explore the reasons for the poor efficacy of anti-angiogenic therapies, aiming to identify some potential therapeutic targets that may enhance the effectiveness of anti-angiogenic treatments.
A massive millisecond magnetar may survive the merger of a neutron star (NS) binary, which would continuously power the merger ejecta. We develop a generic dynamic model for the merger ejecta with ...energy injection from the central magnetar. The ejecta emission (the "merger-nova") powered by the magnetar peaks in the UV band and the peak of the light curve, progressively shifts to an earlier epoch with increasing frequency. A magnetar-powered merger-nova could have an optical peak brightness comparable to a supernova, which is a few tens or hundreds times brighter than the radioactive-powered merger-novae (the so-called macro-nova or kilo-nova). On the other hand, such a merger-nova would peak earlier and have a significantly shorter duration than that of a supernova. An early collapse of the magnetar could suppress the brightness of the optical emission and shorten its duration. Such millisecond-magnetar-powered merger-novae may be detected from NS-NS merger events without an observed short gamma-ray burst, and could be a bright electromagnetic counterpart for gravitational wave bursts due to NS-NS mergers. If detected, it suggests that the merger leaves behind a massive NS, which has important implications for the equation-of-state of nuclear matter.
The discovery of non-Hermitian skin effect (NHSE) has opened an exciting direction for unveiling unusual physics and phenomena in non-Hermitian system. Despite notable theoretical breakthroughs, ...actual observation of NHSE's whole evolvement, however, relies mainly on gain medium to provide amplified mode. It typically impedes the development of simple, robust system. Here, we show that a passive system is fully capable of supporting the observation of the complete evolution picture of NHSE, without the need of any gain medium. With a simple lattice model and acoustic ring resonators, we use complex-frequency excitation to create virtual gain effect, and experimentally demonstrate that exact NHSE can persist in a totally passive system during a quasi-stationary stage. This results in the transient NHSE: passive construction of NHSE in a short time window. Despite the general energy decay, the localization character of skin modes can still be clearly witnessed and successfully exploited. Our findings unveil the importance of excitation in realizing NHSE and paves the way towards studying the peculiar features of non-Hermitian physics with diverse passive platforms.
ABSTRACT Zhang proposed a type of GRB-less X-ray transient associated with double neutron star (NS-NS) mergers under the conjecture of a rapidly spinning magnetar merger product with the line of ...sight off the short gamma-ray burst (GRB) jet. We investigate possible light curves of these transients by considering different observers' viewing angles. We perform Monte Carlo simulations to calculate the peak luminosity function (LF) and event rate density of these X-ray transients. By considering that a fraction of massive neutron stars may be supra-massive and later collapse into black holes after spinning down, we investigate how the predicted LF depends on the equation of state (EoS) of the central object and the geometry of the system. In general, the LF can be fit by two log-normal distributions peaking around and , corresponding to the trapped and free zones, respectively. For the majority of the EoS models, the current non-detection is consistent with having a free zone solid angle, at most a few times the solid angle of the short GRB jet. The event rate density of these X-ray transients is around a few tens of for luminosity above 1045 . We predict that future X-ray telescopes (such as Einstein Probe) with sensitivity would detect as many as several tens of such transients per year per steradian. Within 200 Mpc, the aLIGO average range for NS-NS mergers, the estimated event rate of these transients is about 1 transient per year all sky.
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