Superconductivity and local-moment magnetism in Eu(Fe0.89_{0.89}Co0.11_{0.11})2_{2}As2_{2}

We report the measurements of resistivity and magnetization under magnetic fields parallel and perpendicular to the basal plane, respectively, on a cobalt-doped Eu(Fe$_{0.89}$Co$_{0.11}$)$_{2}$As$_{2}$ single crystal. We observed a resistivity drop at $T_c\sim$ 21 K, which shifts toward lower temperatures under external fields, suggesting a superconducting transition. The upper critical fields near $T_c$ show large anisotropy, in contrast with those of other '122' FeAs-based superconductors. Low-field magnetic susceptibility data also show evidence of superconductivity below 21 K. Instead of expected zero-resistance below $T_c$, however, a resistivity reentrance appears at 17 K under zero field, coincident with the magnetic ordering of Eu$^{2+}$ moments. Based on the temperature and field dependences of anisotropic magnetization, a helical magnetic structure for the Eu$^{2+}$ spins is proposed. External magnetic fields easily changes the helimagnetism into a ferromagnetism with fully polarized Eu$^{2+}$ spins, accompanying by disappearance of the resistivity reentrance. Therefore, superconductivity coexists with ferromagnetic state of Eu$^{2+}$ spins under relatively low magnetic field. The magnetic and superconducting phase diagrams are finally summarized for both $H\parallel ab$ and $H\parallel c$.Comment: 8 pages, 10 figure

Gamellia sinensis O.Ktze extract shows anti-colorectal cancer activity via MAPK/ERK signaling pathway

Purpose: To investigate the therapeutic effects of Gamellia sinensis O.Ktze extract (GSOE) on colorectal cancers, as well as the underlying mechanisms.Methods: The effect of GSOE on colorectal cancer cells HCT-116 or Caco-2 growth was tested, and then the apoptosis and invasion was analyzed by MTT, flow cytometry and Transwell assay in vitro. Next, the mice received three doses (200, 400 or 800 mg/kg/day, gastric perfusion) of GSOE to evaluate its effects on tumor growth. Lung metastasis in mouse xenograft models which were inoculated with HCT-116 or Caco-2 cells were also investigated. The expression of p-ERK and  p-MEK were evaluated by western blot analysis in HCT-116 and Caco-2 cells with or without GSOE treatment in vitro.Result: GSOE significantly inhibited colorectal cancer cell growth and induced  apoptosis or cell cycle arrest at G1- and S-phases in HCT-116 cells and Caco-2 cells in a dose-dependent manner. Moreover, GSOE effectively retarded tumor cell migration and invasion through ERK/MAPK signaling pathway suppression.Conclusion: These findings demonstrate that GSOE has an anti-tumor effect in colorectal cancer by inactivating ERK/MAPK signaling pathway.Keywords: Gamellia sinensis O.Ktze, Colorectal cancer, Invasion, Apoptosis, Cell cycle arrest ERK, MAPK

Entangling two exciton modes using exciton optomechanics

Exciton optomechanics, bridging cavity exciton polaritons and optomechanics, opens new opportunities for the study of light-matter strong interactions and nonlinearities, due to the rich nonlinear couplings among excitons, phonons, and photons. Here, we propose to entangle two exciton modes in an exciton-optomechanical system, which consists of a semiconductor optomechanical microcavity integrated with two quantum wells. The quantum wells support two exciton modes, which simultaneously couple to an optical cavity mode via a linear coupling, and the cavity mode also couples to a mechanical vibration mode via a dispersive optomechanical interaction, accounting for both the radiation pressure and the photoelastic effect. We show that by strongly driving the microcavity with a red-detuned laser field and when the two exciton modes are respectively resonant with the Stokes and anti-Stokes sidebands scattered by the mechanical motion, stationary entanglement between the two exciton modes can be established under currently available parameters. The entanglement is robust against various dissipations of the system and can be achieved at room temperature for a mechanical quality factor higher than $\sim10^4$

Raising the Gangdese Mountains in southern Tibet

This research was financially supported by the MOST of China (No. 2016YFC0600304 and No. 2016YFC0600407), the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (XDB03010301), the National Science Foundation of China (41225006 and 41472061), and the MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources (China University of Geosciences).The surface uplift of mountain belts is in large part controlled by the effects of crustal thickening and mantle dynamic processes (e.g., lithospheric delamination or slab breakoff). Understanding the history and driving mechanism of uplift of the southern Tibetan Plateau requires accurate knowledge on crustal thickening over time. Here we determine spatial and temporal variations in crustal thickness using whole-rock La/Yb ratios of intermediate intrusive rocks from the Gangdese arc. Our results show that the crust was likely of normal thickness prior to ca. 70 Ma (~37 km) but began to thicken locally at ca. 70 − 60 Ma. The crust reached (58 − 50) ± 10 km at 55 − 45 Ma extending over 400 km along the strike of the arc. This thickening was likely due to magmatic underplating as a consequence of rollback and then breakoff of the subducting Neo-Tethyan slab. The crust attained a thickness of 68 ± 12 km at ca. 20 − 10 Ma, as a consequence of underthrusting of India and associated thrust faulting. The Gangdese Mountains in southern Tibet broadly attained an elevation of >4000 m at ca. 55 − 45 Ma as a result of isostatic surface uplift driven by crustal thickening and slab breakoff, and reached their present-day elevation by 20 − 10 Ma. Our paleoelevation estimates are consistent not only with the C − O isotope-based paleoaltimetry but also with the carbonate clumped isotope paleothermometer, exemplifying the promise of reconstructing paleoelevation in time and space for ancient orogens through a combination of magmatic composition and Airy isostatic compensation.Publisher PDFPeer reviewe

Dilepton Rapidity Distribution in Drell-Yan Production to Third Order in QCD

We compute for the first time the lepton-pair rapidity distribution in the photon-mediated Drell-Yan process to next-to-next-to-next-to-leading order in QCD. The calculation is based on the qT-subtraction method, suitably extended to this order for quark-antiquark initiated Born processes. Our results display sizeable QCD corrections at next-to-next-to-next-to-leading order over the full rapidity region and provide a fully independent confirmation of the recent results for the total Drell-Yan cross section at this order

Differential N3LO QCD corrections to charged current production at the LHC

Charged current Drell-Yan production at hadron colliders is a benchmark electroweak process. A recent measurement of the W boson mass by the CDF experiment displays a large deviation from the Standard Model prediction. To enable precision phenomenology for this process, we compute the third-order (N3LO) QCD corrections to the rapidity distribution in W boson production and to the transverse mass distribution of its decay products. We study kinematic regions relevant for the LHC experiments and assess the numerical magnitude of uncertainties from electroweak input parameters and parton distribution functions

Transverse mass distribution and charge asymmetry in W boson production to third order in QCD

Charged gauge boson production at hadron colliders is a fundamental benchmark for the extraction of electroweak parameters and the understanding of the proton structure. To enable precision phenomenology for this process, we compute the third-order (N3LO) QCD corrections to the rapidity distribution and charge asymmetry in W boson production and to the transverse mass distribution of its decay products. Our results display substantial QCD corrections in kinematic regions relevant for Tevatron and LHC measurements. We compare the numerical magnitude of the N3LO corrections with uncertainties from electroweak input parameters and illustrate their potential impact on the determination of the W boson mass