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

The mechanisms of Yu Ping Feng San in tracking the cisplatin-resistance by regulating ATP-binding cassette transporter and glutathione S-transferase in lung cancer cells

Cisplatin is one of the first line anti-cancer drugs prescribed for treatment of solid tumors; however, the chemotherapeutic drug resistance is still a major obstacle of cisplatin in treating cancers. Yu Ping Feng San (YPFS), a well-known ancient Chinese herbal combination formula consisting of Astragali Radix, Atractylodis Macrocephalae Rhizoma and Saposhnikoviae Radix, is prescribed as a herbal decoction to treat immune disorders in clinic. To understand the fast-onset action of YPFS as an anti-cancer drug to fight against the drug resistance of cisplatin, we provided detailed analyses of intracellular cisplatin accumulation, cell viability, and expressions and activities of ATP-binding cassette transporters and glutathione S-transferases (GSTs) in YPFS-treated lung cancer cell lines. In cultured A549 or its cisplatin-resistance A549/DDP cells, application of YPFS increased accumulation of intracellular cisplatin, resulting in lower cell viability. In parallel, the activities and expressions of ATP-binding cassette transporters and GSTs were down-regulated in the presence of YPFS. The expression of p65 subunit of NF-κB complex was reduced by treating the cultures with YPFS, leading to a high ratio of Bax/Bcl-2, i.e. increasing the rate of cell death. Prim-O-glucosylcimifugin, one of the abundant ingredients in YPFS, modulated the activity of GSTs, and then elevated cisplatin accumulation, resulting in increased cell apoptosis. The present result supports the notion of YPFS in reversing drug resistance of cisplatin in lung cancer cells by elevating of intracellular cisplatin, and the underlying mechanism may be down regulating the activities and expressions of ATP-binding cassette transporters and GSTs

Study on the Rotor Strength of High-Speed Permanent Magnet Motor Considering the Influence of Assembly Pressing Force

In engineering application, the hot press assembly technology is often used to improve the stability of the rotor structure, but the conventional design methods cannot effectively evaluate the influence of this process on the rotor strength, which easily causes the rotor strength to exceed its safety margin range, and seriously it will lead to the failure of the rotor structure. This paper takes the cylindrical magnet surface-mounted high-speed permanent magnet synchronous motor rotor as the research object. Firstly, the influence of the assembly pressing force on the rotor stresses and interference is analyzed; then, comprehensively considering the assembly pressing force, speed and temperature, the rotor strength’s design method with high structural stability is proposed. Finally, based on the proposed method, the rotor strength of a 100 kW/30,000 rpm high-speed motor is designed, and the feasibility of the design is verified by over-speed experiment

The effect of parenting styles on depressive symptoms among Chinese college students: The role of subjective well-being and Taq1A polymorphism

Based on different susceptibility models, the current study constructed a moderated mediation model to explore the influence of parenting style on college students’ depressive symptoms. A total of 301 college students (74 boys and 227 girls) participated in this study. Subjective well-being played a mediating role in the effect of parenting style on depressive symptoms. The DRD2 Taq1A polymorphism moderated the direct pathway in the PPS (positive parenting style) model and the second half of the mediating pathway in the NPS (negative parenting style) model. The findings suggest that the Taq1A polymorphism allele A2 is the plasticity gene for depression, and the A2A2 homozygous gene is the most sensitive to environmental stimuli

Rational design of 3D hierarchical foam-like Fe2O3@CuOxmonolith catalysts for selective catalytic reduction of NO with NH3

Herein, we have rationally designed and originally fabricated a high-performance monolith catalyst based on 3D hierarchical foam-like Fe2O3@CuOx for selective catalytic reduction (SCR) of NO with NH3. The Fe2O3@CuOx foam catalyst was synthesized by calcining the Cu foam in air first to form CuOx foam with CuOx nanowire arrays on the surface and then the Fe2O3 could be in situ formed on the surface of CuOx through the reaction in the interfacial region between the aqueous solution of Fe2+ and CuO via a hydrothermal method. This catalyst was mainly characterized by the techniques of X-ray diffraction, transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction, NH3/NO + O2 temperature-programmed desorption and in situ diffuse reflectance infrared Fourier transform spectroscopy. Both the atomic concentration of Cu+ and chemisorbed oxygen species are enhanced by the coating of Fe2O3, which facilitates NO attack on active sites, resulting in the in situ formation of NO2 and promoting the “fast SCR” reaction. Moreover, there is a strong interaction between CuOx and Fe2O3, which could not only lead to better reduction ability but also raise the acid amount and enhance the acid strength as well as NOx adsorption ability. Based on these favourable properties, the Fe2O3@CuOx catalyst exhibits a higher activity and more extensive operating temperature window than the catalyst without Fe2O3. More importantly, the Fe2O3 not only prevents the generation of ammonium sulfates from blocking the active sites but also inhibits the formation of copper sulfates, resulting in a high SO2-tolerance. In addition, the catalyst also displays favourable stability and H2O resistance. The rational design of 3D hierarchical foam-like Fe2O3@CuOx paves a new way for the development of environmentally-friendly and high-performance monolith deNOx catalysts