A theory on skyrmion size Wang, X. S.; Yuan, H. Y.; Wang, X. R.
Communications physics,
07/2018, Letnik:
1, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
A magnetic skyrmion is a topological object consisting of a skyrmion core, an outer domain, and a wall that separates the skyrmion core from the outer domain. The skyrmion size and wall ...width are two fundamental quantities of a skyrmion that depend sensitively on material parameters such as exchange energy, magnetic anisotropy, Dzyaloshinskii–Moriya interaction, and magnetic field. However, quantitative understanding of the two quantities is still very poor. Here we present a general theory on skyrmion size and wall width. The two formulas we obtained agree almost perfectly with simulations and experiments for a wide range of parameters, including most of the existing materials that support skyrmions.
Background
Health‐related quality of life (HRQL) is an important outcome measure in studies of cancer therapy. This study aimed to investigate HRQL and survival in patients with small hepatocellular ...carcinoma (HCC) treated with either surgical resection or percutaneous radiofrequency ablation (RFA).
Methods
Between January 2006 and June 2009, patients with newly diagnosed solitary, small (3 cm or less) HCC were invited to participate in this non‐randomized prospective parallel cohort study. The Functional Assessment of Cancer Therapy – Hepatobiliary (FACT‐Hep) instrument was used for assessing HRQL. HRQL and survival were compared between the two treatment groups.
Results
A total of 389 patients were enrolled. Questionnaires were completed fully by 99·7 per cent of invited participants (388 of 389) at baseline, 98·7 per cent (383 of 388) at 3 months, 99·0 per cent (379 of 383) at 6 months, 98·4 per cent (365 of 371) at 1 year, 96·6 per cent (336 of 348) at 2 years and 95·1 per cent (289 of 304) at 3 years. There were no significant differences in disease‐free and overall survival between the two groups. Patients treated with percutaneous RFA had significantly better HRQL total scores after 3, 6, 12, 24 and 36 months than those who had surgical resection (P < 0·001, P < 0·001, P = 0·001, P = 0·003 and P = 0·025 respectively). On multivariable analysis, the presence of concomitant disease, cirrhosis and surgical resection were significant risk factors associated with a worse HRQL score after treatment.
Conclusion
Percutaneous RFA produced better post‐treatment HRQL than surgical resection for patients with solitary small (no more than 3 cm) HCC.
Radiofrequency ablation is a good alternative for surgery
We report a study of the processes of e^{+}e^{-}→K^{+}D_{s}^{-}D^{*0} and K^{+}D_{s}^{*-}D^{0} based on e^{+}e^{-} annihilation samples collected with the BESIII detector operating at BEPCII at five ...center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7 fb^{-1}. An excess of events over the known contributions of the conventional charmed mesons is observed near the D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0} mass thresholds in the K^{+} recoil-mass spectrum for events collected at sqrts=4.681 GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5_{-2.6}^{+1.8}±2.1) MeV/c^{2} and (12.8_{-4.4}^{+5.3}±3.0) MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3 σ over the contributions only from the conventional charmed mesons. This is the first candidate for a charged hidden-charm tetraquark with strangeness, decaying into D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0}. However, the properties of the excess need further exploration with more statistics.
Superoxide dismutase 1 (Sod1) has been known for nearly half a century for catalysis of superoxide to hydrogen peroxide. Here we report a new Sod1 function in oxidative signalling: in response to ...elevated endogenous and exogenous reactive oxygen species (ROS), Sod1 rapidly relocates into the nucleus, which is important for maintaining genomic stability. Interestingly, H2O2 is sufficient to promote Sod1 nuclear localization, indicating that it is responding to general ROS rather than Sod1 substrate superoxide. ROS signalling is mediated by Mec1/ATM and its effector Dun1/Cds1 kinase, through Dun1 interaction with Sod1 and regulation of Sod1 by phosphorylation at S60, 99. In the nucleus, Sod1 binds to promoters and regulates the expression of oxidative resistance and repair genes. Altogether, our study unravels an unorthodox function of Sod1 as a transcription factor and elucidates the regulatory mechanism for its localization.
We recently reported that ZBTB7A is a bona fide transcription repressor of key glycolytic genes and its downregulation in human cancer contributes to tumor metabolism. As reduced expression of ZBTB7A ...is found only in a subset of human cancers, we explored alternative mechanisms of its inactivation by mining human cancer genome databases. We discovered recurrent somatic mutations of ZBTB7A in multiple types of human cancers with a marked enrichment of mutations within the zinc finger domain. Functional characterization of the mutants demonstrated that mutations within the zinc finger region of ZBTB7A invariably resulted in loss of function. As a consequence, the glycolytic genes were markedly upregulated in cancer cells harboring ZBTB7A zinc finger mutation, leading to increased glycolysis and proliferation. Our study uncovers the loss-of-function mutation in ZBTB7A as a novel mechanism causing elevated glycolysis in human cancer, which carries important therapeutic implication.
The cross section for the process e^{+}e^{-}→π^{+}π^{-}J/ψ is measured precisely at center-of-mass energies from 3.77 to 4.60 GeV using 9 fb^{-1} of data collected with the BESIII detector operating ...at the BEPCII storage ring. Two resonant structures are observed in a fit to the cross section. The first resonance has a mass of (4222.0±3.1±1.4) MeV/c^{2} and a width of (44.1±4.3±2.0) MeV, while the second one has a mass of (4320.0±10.4±7.0) MeV/c^{2} and a width of (101.4_{-19.7}^{+25.3}±10.2) MeV, where the first errors are statistical and second ones are systematic. The first resonance agrees with the Y(4260) resonance reported by previous experiments. The precision of its resonant parameters is improved significantly. The second resonance is observed in e^{+}e^{-}→π^{+}π^{-}J/ψ for the first time. The statistical significance of this resonance is estimated to be larger than 7.6σ. The mass and width of the second resonance agree with the Y(4360) resonance reported by the BABAR and Belle experiments within errors. Finally, the Y(4008) resonance previously observed by the Belle experiment is not confirmed in the description of the BESIII data.
Several preclinical studies have reported the rapid antidepressant effects of N-methyl-D-aspartate receptor (NMDAR) antagonists, although the underlying mechanisms are still unclear. Death-associated ...protein kinase 1 (DAPK1) couples GluN2B subunits at extrasynaptic sites to regulate NMDAR channel conductance. In the present study, we found that chronic unpredictable stress (CUS) induced extracellular glutamate accumulation, accompanied by an increase in the DAPK1-NMDAR interaction, the high expression of DAPK1 and phosphorylated GluN2B at Ser1303, a decrease in phosphorylated DAPK1 at Ser308 and synaptic protein deficits in the rat medial prefrontal cortex (mPFC). CUS also enhanced GluN2B-mediated NMDA currents and extrasynaptic responses that were induced by bursts of high-frequency stimulation, which may be associated with the loss of astrocytes and low expression of glutamate transporter-1 (GLT-1). The blockade of GLT-1 in the mPFC was sufficient to induce depressive-like behavior and cause similar molecular changes. Selective GluN2B antagonist, DAPK1 knockdown by adeno-associated virus-mediated short-hairpin RNA or a pharmacological inhibitor, and the uncoupling of DAPK1 from the NMDAR GluN2B subunit produced rapid antidepressant-like effects and reversed CUS-induced alterations in the mPFC. The inhibition of DAPK1 and its interaction with GluN2B subunit in the mPFC also rescued CUS-induced depressive-like behavior 7 days after treatment. A selective GluN2B antagonist did not have rewarding effects in the conditioned place preference paradigm. Altogether, our findings suggest that the DAPK1 interaction with the NMDAR GluN2B subunit acts as a critical component in the pathophysiology of depression and is a potential target for new antidepressant treatments.
The processes X(3872) ... , and γD+D− are searched for in a 9.0 fb−1 data sample collected at center-of-mass energies between 4.178 and 4.278 GeV with the BESIII detector. We observe X(3872) ... . ...and find evidence for X (3872)→γJ/ψ with statistical significances of 7.4 σ and 3.5σ, respectively. No evident signals for X(3872)→γψ(2S) and γD+D− are found, and the upper limit on the relative branching ratio Rγψ ≡ {BX(3872)→γψ(2S)}/{BX(3872)→γJ/ψ} <0.59 is set at 90% confidence level. Measurements of branching ratios relative to decay X(3872)→π+π−J/ψ are also reported for decays ... .,γψ(2S), γJ/ψ, and γD+D−, as well as the non-... three-body decays ... .(ProQuest: ... denotes formulae omitted.)
Highlights • The expression of PHB1 was downregulated following SCI in rats. • Ad-PHB1 administration promoted functional recovery in rats with SCI. • Ad-PHB1 administration following SCI reduced ...apoptosis. • Ad-PHB1 administration following SCI suppressed ER stress. • Ad-PHB1 administration following SCI restored mitochondrial function.
The exclusive process e+e−→ΛΛ¯, with Λ→pπ− and Λ¯→p¯π+, has been studied at s=2.396 GeV for measurement of the timelike Λ electric and magnetic form factors, GE and GM. A data sample, corresponding ...to an integrated luminosity of 66.9 pb−1, was collected with the BESIII detector for this purpose. A multidimensional analysis with a complete decomposition of the spin structure of the reaction enables a determination of the modulus of the ratio R=|GE/GM| and, for the first time for any baryon, the relative phase ΔΦ=ΦE−ΦM. The resulting values are R=0.96±0.14(stat)±0.02(syst) and ΔΦ=37°±12°(stat)±6°(syst), respectively. These are obtained using the recently established and most precise value of the asymmetry parameter αΛ=0.750±0.010 measured by BESIII. In addition, the cross section is measured with unprecedented precision to be σ=118.7±5.3(stat)±5.1(syst) pb, which corresponds to an effective form factor of |G|=0.123±0.003(stat)±0.003(syst). The contribution from two-photon exchange is found to be negligible. Our result enables the first complete determination of baryon timelike electromagnetic form factors.
PDF
