611 research outputs found
Chemical freeze-out parameters via functional renormalization group approach
We study the freeze-out parameters in a QCD-assisted effective theory that
accurately captures the quantum and in-medium effects of QCD at low energies.
Functional renormalization group approach is implemented in our work to
incorporate the non-perturbative quantum, thermal and density fluctuations. By
analyzing the calculated baryon number susceptibility ratios
and , we determine the
chemical freeze-out temperatures and baryon chemical potentials in cases of
hard thermal or dense loop improved -dependent glue potential and
-independent glue potential. We calculate the
and
along the freeze-out line for both cases. It's
found that exhibits a nonmonotonic behavior in low
collision energy region and approach to one for lower collision energy.
shows a similar complicated behavior in our
calculation.Comment: 14 pages, 11 figures, 7 table
Comparative study of gamma-ray emission from molecular clouds and star-forming galaxies
Star-forming regions on different scales, such as giant molecular clouds in
our Galaxy and star-forming galaxies, emit GeV gamma-rays. These are thought to
originate from hadronic interactions of cosmic-ray (CR) nuclei with the
interstellar medium. It has recently been shown that the gamma-ray luminosity
() of star-forming galaxies is well correlated with their star
formation rates (SFR). We investigated \textsl{Fermi} data of eight Galactic
molecular clouds in the Gould belt and found that molecular clouds do not
follow the correlation of star-forming galaxies. We also
compared the scaling relations of gamma-ray luminosity, SFR, and the gas mass
for molecular clouds and star-forming galaxies. Using a multiple-variable
regression analysis, we found different dependences of gamma-ray emission on
SFR or mass for molecular clouds and star-forming galaxies. This suggests that
different mechanisms may govern the production of gamma-rays in these two types
of sources. Specifically, the strong dependence on mass supports that gamma-ray
emission of molecular clouds primarily comes from {\em \textup{passive}}
interaction by diffuse Galactic CRs, whereas the strong dependence on SFR
supports that gamma-ray emission of star-forming galaxies originates from CRs
that are accelerated by local {\em \textup{active}} sources.Comment: Accepted for publication in Astronomy & Astrophysic
A chalcone derivative reactivates latent HIV-1 transcription through activating P-TEFb and promoting Tat-SEC interaction on viral promoter.
The principal barrier to the eradication of HIV/AIDS is the existence of latent viral reservoirs. One strategy to overcome this barrier is to use latency-reversing agents (LRAs) to reactivate the latent proviruses, which can then be eliminated by effective anti-retroviral therapy. Although a number of LRAs have been found to reactivate latent HIV, they have not been used clinically due to high toxicity and poor efficacy. In this study, we report the identification of a chalcone analogue called Amt-87 that can significantly reactivate the transcription of latent HIV provirses and act synergistically with known LRAs such as prostratin and JQ1 to reverse latency. Amt-87 works by activating the human transcriptional elongation factor P-TEFb, a CDK9-cyclin T1 heterodimer that is part of the super elongation complex (SEC) used by the viral encoded Tat protein to activate HIV transcription. Amt-87 does so by promoting the phosphorylation of CDK9 at the T-loop, liberating P-TEFb from the inactive 7SK snRNP, and inducing the formation of the Tat-SEC complex at the viral promoter. Together, our data reveal chalcones as a promising category of compounds that should be further explored to identify effective LRAs for targeted reversal of HIV latency
Manifold formation and crossings of ultracold lattice spinor atoms in the intermediate interaction regime
Ultracold spinor atoms in the weak and strong interaction regime have
received extensive investigations, while the behavior in the intermediate
regime is less understood. We numerically investigate ultracold spinor atomic
ensembles of finite size in the intermediate interaction regime, and reveal the
evolution of the eigenstates from the strong to the intermediate regime. In the
strong interaction regime, it has been well known that the low-lying
eigenenergy spectrum presents the well-gaped multi-manifold structure, and the
energy gaps protect the categorization of the eigenstates. In the intermediate
interaction regime, it is found that the categorization of the eigenstates is
preserved, and the eigenenergy spectrum become quasi-continuum, with different
manifolds becoming overlapped. The overlapping induces both direct and avoided
crossings between close-lying manifolds, which is determined by the combined
symmetries of the eigenstates involved in the crossing. A modified t-J model is
derived to describe the low-lying eigenstates in the intermediate regime, which
can capture the formation and crossings of the manifolds. State preparation
through the avoided crossings is also investigated.Comment: 8 pages,6 figure
Detrimental effect of Bisphenol S in mouse germ cell cyst breakdown and primordial follicle assembly
The female reproductive lifespan is largely determined by the size of primordial follicle pool, which is established in early life. Bisphenol S (BPS), frequently present in plastic products used in daily life, has been demonstrated as an exogenous estrogen-like endocrine disrupting chemical interfering with the endocrine and reproductive systems. However, the molecular mechanisms of its reproductive toxicity remain to be determined. In the present study, we focused on the effect of BPS on the early ovarian folliculogenesis of mice. Our in vivo experiments showed that the treatment with BPS at 2 and 10 μg/kg body weight/day for 3 days induced abnormal germ cell cyst breakdown and primordial follicle assembly in the mouse ovary, further affecting later ovarian differentiation and reducing oocyte quality. In addition, our in vitro study demonstrated that BPS could interact with estrogen receptors (ERs) to induce phosphorylation of JNKs, which is responsible for reducing oocyte adhesion in cysts. Meanwhile, BPS exposure up-regulated Notch signaling pathway to increase the proliferation of granulosa cells precursors. Our study provided new evidence for the adverse effects of BPS on female reproduction, especially after perinatal exposure, and elucidated how it works
Malignant Mesothelioma Presenting as a Giant Chest, Abdominal and Pelvic Wall Mass
Malignant mesothelioma (MM) is a relatively rare carcinoma of the mesothelial cells, and it is usually located in the pleural or peritoneal cavity. Here we report on a unique case of MM that developed in the chest, abdominal and pelvic walls in a 77-year-old female patient. CT and MRI revealed mesothelioma that manifested as a giant mass in the right flank and bilateral pelvic walls. The diagnosis was confirmed by the pathology and immunohistochemistry. Though rare, accurate investigation of the radiological features of a body wall MM may help make an exact diagnosis
Interaction effects of pseudospin-based magnetic monopoles and kinks in a doped dipolar superlattice gas
Magnetic monopoles and kinks are topological excitations extensively
investigated in quantum spin systems, but usually they are studied in different
setups. We explore the conditions for the coexistence and the interaction
effects of these quasiparticles in the pseudospin chain of the atomic dipolar
superlattice gas. In this chain, the magnetic kink is the intrinsic
quasiparticle, and the particle/hole defect takes over the role of the
north/south magnetic monopole, exerting monopolar magnetic fields to
neighboring spins. A confinement effect between the monopole and kink is
revealed, which renormalizes the dispersion of the kink. The corresponding
dynamical deconfinement process is observed and arises due to the kink-antikink
annihilation. The rich interaction effects of the two quasiparticles could
stimulate corresponding investigations in bulk spin systems
Magnetic monopole induced polarons in atomic superlattices
Magnetic monopoles have been realized as emergent quasiparticles in both
condensed matter and ultracold atomic platforms, with growing interests in the
coupling effects between the monopole and different magnetic quasiparticles. In
this work, interaction effects between monopoles and magnons are investigated
for an atomic pseudospin chain. We reveal that the monopole can excite a
virtual magnon cloud in the paramagnetic chain, thereby giving rise to a new
type of polaron, the monopole-cored polaron (McP). The McP is composed of the
monopole as the impurity core and the virtual magnon excitation as the dressing
cloud. The magnon dressing facilitates the Dirac string excitation and impacts
the monopole hopping. This induces an anti-trapping effect of the McP, which
refers to the fact that the dressing enhances the mobility of the McP, in
contrast to the self-trapping of the common polarons. Moreover, heterogeneous
bipolarons are shown to exist under the simultaneous doping of a north and a
south monopole. The heterogeneous bipolaron possesses an inner degree of
freedom composed of two identical impurities. Our investigation sheds light on
the understanding of how the coupling between the impurity core and the
dressing cloud can engineer the property of the polaro
- …