Stable nontrivial Z2 topology in ultrathin Bi (111) films: a first-principles study

Recently, there have been intense efforts in searching for new topological insulator (TI) materials. Based on first-principles calculations, we find that all the ultrathin Bi (111) films are characterized by a nontrivial Z2 number independent of the film thickness, without the odd-even oscillation of topological triviality as commonly perceived. The stable nontrivial Z2 topology is retained by the concurrent band gap inversions at multiple time-reversal-invariant k-points and associated with the intermediate inter-bilayer coupling of the multi-bilayer Bi film. Our calculations further indicate that the presence of metallic surface states in thick Bi(111) films can be effectively removed by surface adsorption.Comment: 5 pages, 3 figure

Higher-order generalized uncertainty principle applied to gravitational baryogenesis

The gravitational baryogenesis plays an important role in the study of the baryon asymmetry. However, the original mechanism of gravitational baryogenesis in the radiation dominated era leads to the asymmetry factor $\eta$ is equal to zero, which indicates this mechanism may not generate a sufficient baryon asymmetry for the standard cosmological model. In this manuscript, we investigate the gravitational baryogenesis for the generation of baryon asymmetry in the early Universe by using an new higher-order generalized uncertainty principle (GUP). It is demonstrated that the entropy and Friedman equation of the Universe deviate from the original cases due to the effect of the higher-order GUP. Those modifications break the thermal equilibrium of the Universe and in turn produces a non-zero asymmetry factor $\eta$. In particular, our results satisfy all three Sakharov conditions, which indicates that the scheme of explaining baryon asymmetry in the framework of higher-order GUP is feasible. In addition, confronting our theoretical results with the observational results, we constraint the GUP parameter $\beta_0$, whose bound between $8.4 \times {10^{10}} \sim 1.1 \times {10^{13}}$.Comment: 8 pages, 1 figur

The generalized uncertainty principle impact onto the black hole thermodynamic phase transition

In this work, we conduct a study regarding the local thermodynamic quantities and the phase transition of a black hole subject to the generalized uncertainty principle. The results demonstrate that both the positive and negative generalized uncertainty principle parameters $\beta_0$ can significantly affect the thermodynamic evolution, stability, critical behavior, and phase transition of the black hole. For $\beta_0>0$, the black hole forms a thermodynamic remnant with finite temperature and finite mass but zero local heat capacity in the last stages of evolution. Meanwhile, it has one second-order phase transitions and two Hawking-Page-type phase transitions. The Gross-Perry-Yaffe phase transition occurs for both large black hole state and small black hole state. For $\beta_0<0$, the Gross-Perry-Yaffe phase transition occurs only for large black hole state, and the temperature and heat capacity of black hole remnant is finite, whereas its mass is zero. This indicates the remnant is metastable and would be in the Hawking-Page-type phase transition forever. In addition, according to the viewpoint of corpuscular gravity, the remnant can be interpreted as an additional TBH configuration, which never appears in the original case and the positive correction case.Comment: 7 Pages, 3 figure

Topological quantum phase transition in an extended Kitaev spin model

We study the quantum phase transition between Abelian and non-Abelian phases in an extended Kitaev spin model on the honeycomb lattice, where the periodic boundary condition is applied by placing the lattice on a torus. Our analytical results show that this spin model exhibits a continuous quantum phase transition. Also, we reveal the relationship between bipartite entanglement and the ground-state energy. Our approach directly shows that both the entanglement and the ground-state energy can be used to characterize the topological quantum phase transition in the extended Kitaev spin model.Comment: 9 Pages, 4 figure

Guanylate-binding protein 1 participates in cellular antiviral response to dengue virus

BACKGROUND: Dengue virus (DENV), the causative agent of human Dengue hemorrhagic fever, is a mosquito-borne virus found in tropical and sub-tropical regions around the world. Vaccines against DENV are currently unavailable. Guanylate-binding protein 1 (GBP1) is one of the Interferon (IFN) stimulated genes (ISGs) and has been shown important for host immune defense against various pathogens. However, the role of GBP1 during DENV infection remains unclarified. In this study, we evaluated the relevance of GBP1 to DENV infection in in vitro model. FINDINGS: Quantitative RT-PCR (qRT-PCR) and Western blot showed that the expression of mouse Gbp1 was dramatically upregulated in DENV-infected RAW264.7 cells. The intracellular DENV loads were significantly higher in Gbp1 silenced cells compared with controls. The expression levels of selective anti-viral cytokines were decreased in Gbp1 siRNA treated cells, while the transcription factor activity of NF-κB was impaired upon GBP1 silencing during infection. CONCLUSIONS: Our data suggested that GBP1 plays an antiviral role during DENV infection

Clinical evaluation on the coaxial microincision cataract surgery in hard nuclear cataracts

AIM: To assess and compare the results of 2.2mm microincision coaxial cataract surgery(MCCS)phacoemulsification with the conventional 3.0mm MCCS in hard nuclear cataracts. METHODS: Totally 132 eyes with hard cataract(Ⅳ level and above)were randomized to two groups: 2.2mm MCCS(group 1:60 eyes)and 3.0mm MCCS(group 2:72 eyes). All patients underwent standard phacoemulsification and intraocular lens implantation surgery by one experienced surgeon. The average ultrasound power(AVE)was recorded during the operation. The incidences of capsule rupture and postoperative corneal edema were compared.Visual acuity, surgically induced astigmatism(SIA)and the descent rate of endothelial cell density were compared at intervals of 1 day, 1 month and 3 months after surgery. Statistic analysis was taken by Student's t test and Chi square test. RESULTS: There was no significant difference on the incidences of capsule rupture, postoperative corneal edema and AVE(P> 0.05)between the two groups(3.3%, 10.0%, 65.09±20.15)and(4.2%, 11.1%, 69.13±15.44). One day after the surgery, the 2.2mm MCCS group showed better uncorrected visual acuity as compared to the 3.0mm MCCS group(P < 0.05). There were no significant differences on best-corrected visual acuity on 1 month and 3 months after the surgery. There was no significant difference on the descent rate of endothelial cell density(16.54%±10.20%, 17.69%±10.65%)3 months after the surgery. One day, 1 month and 3 months after the surgery, SIA was 0.77±0.31,0.66±0.29, 0.52±0.25D in the 2.2mm MCCS group, and 1.41±0.73,0.98±0.61D,0.82±0.35D in the 3.0mm MCCS group, respectively. The differences were statistically significant. CONCLUSION: The operative safety of the 2.2mm MCCS group were the same as 3.0mm MCCS group with the hard nuclear cataracts. The 2.2mm MCCS phacoemulsification could significantly reduce SIA and get better earlier visual rehabilitation