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A properly strained graphene monolayer or bilayer is expected to harbour periodic pseudo-magnetic fields with high symmetry, yet to date, a convincing demonstration of such pseudo-magnetic fields has been lacking, especially for bilayer graphene. Here, we report the first definitive experimental proof for the existence of large-area, periodic pseudo-magnetic fields, as manifested by vortex lattices in commensurability with the moiré patterns of low-angle twisted bilayer graphene. The pseudo-magnetic fields are strong enough to confine the massive Dirac electrons into circularly localized pseudo-Landau levels, as observed by scanning tunneling microscopy/spectroscopy, and also corroborated by tight-binding calculations. We further demonstrate that the geometry, amplitude, and periodicity of the pseudo-magnetic field can be fine-tuned by both the rotation angle and heterostrain applied to the system. Collectively, the present study substantially enriches twisted bilayer graphene as a powerful enabling platform for exploration of new and exotic physical phenomena, including quantum valley Hall effects and quantum anomalous Hall effects.

Ammonia (NH3) is the main raw material for the organic chemical industry and a critical feedstock for the fertilizer industry with great significance for the global economy. NH3 demand has...

BackgroundHypertension is a highly prevalent disease and the leading cause of chronic kidney disease (CKD). Metabolic syndrome could also be the risk factor for CKD. We sought to study the association between metabolic syndrome components and the prevalence of CKD in patients with hypertension.MethodsWe carried out a multi-center cross-sectional study from Apr. 2017- Apr. 2018 in 15 cities in China.ResultsA total of 2484 patients with hypertension were enrolled. Among them, 56% were male and the average age was 65.12 ± 12.71 years. The systolic BP/diastolic BP was 142 ± 18/83 ± 12 mmHg. Metabolic syndrome components turned out to be highly prevalent in patients with hypertension, ranging from 40 to 58%. The prevalence of chronic kidney disease reached 22.0%. Multi-variate logistic analysis revealed that elevated triglyceride (TG) (OR = 1.81, 95% CI 1.28–2.57, p < 0.01), elevated fasting blood glucose (FBG) (OR = 1.43, 95% CI 1.00–2.07, p = 0.05) and hypertension grades (OR = 1.20, 95% CI 1.00–1.44, p = 0.05) were associated with the prevalence of CKD. In sub-group analysis, elevated TG remained strongly associated with CKD in both diabetes (OR = 2.10, 95%CI 1.22–3.61, p < 0.01) and non-diabetes (OR = 1.53, 95% CI 1.09–2.16, p = 0.01). In sub-group analysis of hypertension grades, there was also a graded trend between elevated TG and CKD from controlled blood pressure (BP) to hypertension grade 2 (OR = 1.81, 95%CI 1.06–3.11, p = 0.03; OR = 1.85, 95%CI 1.00–3.43, p = 0.05; OR = 2.81, 95% CI 1.09–7.28, p = 0.03, respectively).ConclusionElevated TG, elevated FBG and hypertension grades were significantly associated with the prevalence of CKD in patients with hypertension. Particularly, elevated TG was strongly associated with CKD, independent of diabetes and hypertension grades.

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Employing a nickel catalyst and electron-deficient polyfluoroaryl magnesium species, a highly selective monoarylation of polyfluoroarenes containing multiple identical coupling sites has been achieved for the first time, which represents a long-standing problem due to the competitive reactivity between the desired products and the starting polyfluoroarenes. Because of the negative fluorine effect, a surprisingly stable cis [Ni(Ar F4 ) 2 (DPEPhos)] species 4 (Ar F4 = 2,3,5,6tetrafluorophenyl) confirmed by X-ray crystallography is isolated, which acts as catalyst arrest state as proven by a thermal decomposition test. Further retro-transmetalation experiments uncover a hidden secondary transmetalation between Ar F4 -Ni-Ph and excess Ar F4 -MgCl that competes with the desired but reluctant reductive elimination at the high-valent nickel center. Accordingly, through the cooperation of newly developed DMM-DPEPhos, and a dioxane-mediated Schlenk equilibrium with Grignard reagent, the formation of the corresponding arrest state is remarkably inhibited. An excellent coupling efficiency and an excellent monoarylation selectivity are therefore generally accomplished with a widespread electrophile scope and good functional group tolerance under mild conditions. Importantly, our novel method shows great power in the gram-scale synthesis of thienyl-2,3,5,6-tetrafluorophenyl units that represent key components in materials science.