A Study of the Merger History of the Galaxy Group HCG 62 Based on X-Ray Observations and SPH Simulations

We choose the bright compact group HCG 62, which was found to exhibit both excess X-ray emission and high Fe abundance to the southwest of its core, as an example to study the impact of mergers on chemical enrichment in the intragroup medium. We first reanalyze the high-quality Chandra and XMM-Newton archive data to search for the evidence for additional SN II yields, which is expected as a direct result of the possible merger-induced starburst. We reveal that, similar to the Fe abundance, the Mg abundance also shows a high value in both the innermost region and the southwest substructure, forming a high-abundance plateau, meanwhile all the SN Ia and SN II yields show rather flat distributions in $>0.1r_{200}$ in favor of an early enrichment. Then we carry out a series of idealized numerical simulations to model the collision of two initially isolated galaxy groups by using the TreePM-SPH GADGET-3 code. We find that the observed X-ray emission and metal distributions, as well as the relative positions of the two bright central galaxies with reference to the X-ray peak, can be well reproduced in a major merger with a mass ratio of 3 when the merger-induced starburst is assumed. The `best-match' snapshot is pinpointed after the third pericentric passage when the southwest substructure is formed due to gas sloshing. By following the evolution of the simulated merging system, we conclude that the effects of such a major merger on chemical enrichment are mostly restricted within the core region when the final relaxed state is reached.Comment: Accepted for publication in the Astrophysical Journa

Pholidota chinensis alleviates azoxymethane/dextran sulfate sodium-induced colorectal carcinogenesis through inhibition of TLR4 and COX-2

Background: Inflammatory bowel disease (IBD) always progresses to colorectal cancer (CRC) which is the second most frequent cause of death by cancer. It is about 2% of population in the lifetime worldwide who at the risk for development of CRC. Oxaliplatin is an effective anticancer drug used for the treatment of advanced CRC; however, it always causes a robust painful neuropathy. Pholidota chinensis is a Chinese folk herbal medicine which was used for treatment of inflammation such as gastroenteritis, duodenal ulcer and bronchitis.Materials and Methods: The azoxymethane (AOM) and dextran sulfate sodium (DSS) were used to induce the colon tumor of mice. The effect of Pholidota chinensis on colon tumorigenesis was evaluated. Immunohistochemistry and semi-quantitative RT-PCR were used to detect the expression of toll-like receptor 4 (TLR4) and cyclooxygenase-2 (COX-2) in colon.Results: Pholidota chinensis can alleviate the colon tumorigenesis. The prevention effects of Pholidota chinensis are similar to oxaliplatin. Specifically, administration of Pholidota chinensis solution suppresses the expression of the proliferating cell nuclear antigen (PCNA), toll-like receptor 4 (TLR4) and cyclooxygenase-2 (COX-2).Conclusion: Our findings suggested that Pholidota chinensis participate in the regulation of colon cancer development through inhibiting the expression of TLR4 and COX-2.Keywords: Pholidota chinensis; colorectal cancer; Toll-like receptor 4; Cyclooxygenase-

Exclusive Charmonium Production at the Electron-ion collider in China

We investigate the exclusive $J/\psi$ production at the future Electron-ion collider in China by utilizing the eSTARlight event generator. We model the cross-section and kinematics by fitting to the world data of $J/\psi$ photoproduction. Projected statistical uncertainties on $J/\psi$ production are based on the design of a central detector, which consists of a tracker and vertex subsystem. The precision of the pseudo-data allows us to probe the near-threshold mechanism, e.g. the re-scattering effect. The significance of the forward amplitudes is discussed as well. The design and optimization of the detector enhance the potential for exploring the near-threshold region and the realm of high four-momentum transfer squared.Comment: 10 pages, 11 figure

Shape complexity and fractality of fracture surfaces of swelled isotactic polypropylene with supercritical carbon dioxide

We have investigated the fractal characteristics and shape complexity of the fracture surfaces of swelled isotactic polypropylene Y1600 in supercritical carbon dioxide fluid through the consideration of the statistics of the islands in binary SEM images. The distributions of area $A$, perimeter $L$, and shape complexity $C$ follow power laws $p(A)\sim A^{-(\mu_A+1)}$, $p(L)\sim L^{-(\mu_L+1)}$, and $p(C)\sim C^{-(\nu+1)}$, with the scaling ranges spanning over two decades. The perimeter and shape complexity scale respectively as $L\sim A^{D/2}$ and $C\sim A^q$ in two scaling regions delimited by $A\approx 10^3$. The fractal dimension and shape complexity increase when the temperature decreases. In addition, the relationships among different power-law scaling exponents $\mu_A$, $\mu_B$, $\nu$, $D$, and $q$ have been derived analytically, assuming that $A$, $L$, and $C$ follow power-law distributions.Comment: RevTex, 6 pages including 7 eps figure

Reliable and stable fundus image registration based on brain-inspired spatially-varying adaptive pyramid context aggregation network

The task of fundus image registration aims to find matching keypoints between an image pair. Traditional methods detect the keypoint by hand-designed features, which fail to cope with complex application scenarios. Due to the strong feature learning ability of deep neural network, current image registration methods based on deep learning directly learn to align the geometric transformation between the reference image and test image in an end-to-end manner. Another mainstream of this task aims to learn the displacement vector field between the image pair. In this way, the image registration has achieved significant advances. However, due to the complicated vascular morphology of retinal image, such as texture and shape, current widely used image registration methods based on deep learning fail to achieve reliable and stable keypoint detection and registration results. To this end, in this paper, we aim to bridge this gap. Concretely, since the vessel crossing and branching points can reliably and stably characterize the key components of fundus image, we propose to learn to detect and match all the crossing and branching points of the input images based on a single deep neural network. Moreover, in order to accurately locate the keypoints and learn discriminative feature embedding, a brain-inspired spatially-varying adaptive pyramid context aggregation network is proposed to incorporate the contextual cues under the supervision of structured triplet ranking loss. Experimental results show that the proposed method achieves more accurate registration results with significant speed advantage

PRNP Sequences of Tibetan Antelope, Blue Sheep, and Plateau Pika from the Qinghai-Tibet Plateau and Reactivity of PrP Proteins to Rodent-Adapted Scrapie Strains in RT-QuIC and PMCA

Tibetan antelope ( Rhinopithecus ), blue sheep ( Pseudois nayauris ), and plateau pika ( Ochotona curzoniae ) are wild animals living on the Qinghai-Tibet Plateau. There have been no reports of naturally-occurring transmissible spongioform encephalopathies (TSEs) involving these animals. Furthermore, the PRNP genes have not been described in the literature. The PRNP genes from 21 Tibetan antelopes, 4 blue sheep, and 3 plateau pikas were obtained and sequenced. The recombinant proteins were then prepared. Using scrapie strains (263K, 139A, ME7, and S15) as the seeds, the reactivity of the PrP proteins from sheep (rSheepPrP25-234) and pika (rPikaPrP23-230) were tested using real-time quaking-induced conversion (RT-QuIC). Protein misfolding cyclic amplification (PMCA) tests of the brain homogenates from domestic sheep and rabbits were performed with the seeds of strains 263K and ME7. The PRNP genes of bovids were 771 bp long and encoded 256 amino acids (aa), showing 100% homology with the wild-type sheep prion protein (PrP) aa sequence. The PRNP gene of pika was 759 bp long and encoded 252 amino acids, showing 92.1% homology with the aa sequence of domestic rabbits. The sheep and pika proteins revealed positive reactions in 10 -5 diluted seeds. Only rPikaPrP23-230 produced positive curves in 10 -7 diluted seeds. The PMCA tests failed to produce proteinase K (PK)-resistant PrP (PrP res ). This is the first description of PRNP genes and PrP aa sequences of Tibetan antelope, blue sheep, and plateau pike from the Qinghai-Tibet Plateau. In the presence of rodent prions, the PrPs of sheep and pika efficiently induce fibrillation in RT-QuIC, but do not generate PrP res in PMCA. Our results indicate that pika, as one of the important links in the Qinghai-Tibet Plateau biological chain, may play an important role in the prion circulation. Pika PrP deserves further analysis for its potential application value in assays for human prion disease

Magnetic activities and parameters of 43 flare stars in the GWAC archive

In the archive of the Ground Wide Angle Camera (GWAC), we found 43 white light flares from 43 stars, among which, three are sympathetic or homologous flares, and one of them also has a quasi-periodic pulsation with a period of $13.0\pm1.5$ minutes. Among these 43 flare stars, there are 19 new active stars and 41 stars that have available TESS and/or K2 light curves, from which we found 931 stellar flares. We also obtained rotational or orbital periods of 34 GWAC flare stars, of which 33 are less than 5.4 days, and ephemerides of three eclipsing binaries from these light curves. Combining with low resolution spectra from LAMOST and the Xinglong 2.16m telescope, we found that $L_{\rm H\alpha}/L_{\rm bol}$ are in the saturation region in the rotation-activity diagram. From the LAMOST medium-resolution spectrum, we found that Star \#3 (HAT 178-02667) has double H$\alpha$ emissions which imply it is a binary, and two components are both active stars. Thirteen stars have flare frequency distributions (FFDs) from TESS and/or K2 light curves. These FFDs show that the flares detected by GWAC can occur at a frequency of 0.5 to 9.5 yr$^{-1}$. The impact of flares on habitable planets was also studied based on these FFDs, and flares from some GWAC flare stars may produce enough energetic flares to destroy ozone layers, but none can trigger prebiotic chemistry on their habitable planets.Comment: 20 pages, 9 figures, 3 table