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Abstract Folic acid, served as dietary supplement, is closely linked to one-carbon metabolism and methionine metabolism. Previous clinical evidence indicated that folic acid supplementation displays dual effect on cancer development, promoting or suppressing tumor formation and progression. However, the underlying mechanism remains to be uncovered. Here, we report that high-folate diet significantly promotes cancer development in mice with hepatocellular carcinoma (HCC) induced by DEN/high-fat diet (HFD), simultaneously with increased expression of methionine adenosyltransferase 2A (gene name, MAT2A; protein name, MATIIα), the key enzyme in methionine metabolism, and acceleration of methionine cycle in cancer tissues. In contrast, folate-free diet reduces MATIIα expression and impedes HFD-induced HCC development. Notably, methionine metabolism is dynamically reprogrammed with valosin-containing protein p97/p47 complex-interacting protein (VCIP135) which functions as a deubiquitylating enzyme to bind and stabilize MATIIα in response to folic acid signal. Consistently, upregulation of MATIIα expression is positively correlated with increased VCIP135 protein level in human HCC tissues compared to adjacent tissues. Furthermore, liver-specific knockout of Mat2a remarkably abolishes the advocating effect of folic acid on HFD-induced HCC, demonstrating that the effect of high or free folate-diet on HFD-induced HCC relies on Mat2a. Moreover, folate and multiple intermediate metabolites in one-carbon metabolism are significantly decreased in vivo and in vitro upon Mat2a deletion. Together, folate promotes the integration of methionine and one-carbon metabolism, contributing to HCC development via hijacking MATIIα metabolic pathway. This study provides insight into folate-promoted cancer development, strongly recommending the tailor-made folate supplement guideline for both sub-healthy populations and patients with cancer expressing high level of MATIIα expression.

Computed tomography (CT) scanning technology is helpful in investigating rock materials as it can demonstrate the micro structure of rock clearly. Conventional triaxial compression tests and the corresponding graded triaxial loading tests were carried out to investigate the complex failure mechanism of the marble at the Jinping Hydropower Station. After that CT-scanning tests were done on the loaded marble specimens. The test results show that (1) the CT numbers of the specimens have a certain statistical regularity, that is, the CT numbers of the specimens under different confining pressures satisfy the Weibull distribution, as the confining pressure increases, the mean values rise while variances decrease; (2) in the two groups of tests, the average CT numbers corresponding to the conventional triaxial tests are higher than those corresponding to the graded loading tests, but the CT number variances are lower than those of the graded loading tests; and (3) according to meso-damage mechanics, the damage variables of the rock specimens were established based on the definition of CT numbers. The calculation results show that the damage variables decrease with the increase in confining pressure, the damage variables of the rock specimens in the graded loading tests are higher than those in the conventional triaxial test, and the differences between the two loading tests have grown with the increase in confining pressure.

The energy dissipation usually occurs during rock failure, which can demonstrate the meso failure process of rock in a relatively accurate way. Based on the results of conventional triaxial compression experiments on the Jinping marble, a numerical biaxial compression model was established by PFC2D to observe the development of the micro-cracks and energy evolution during the test, and then the laws of crack propagation, energy dissipation and damage evolution were analyzed. The numerical simulation results indicate that both the crack number and the total energy dissipated during the loading process increase with confining pressures, which is basically consistent with the experiment results. Two damage variables were presented in terms of the density from other researchers’ results and energy dissipation from numerical simulation, respectively. The energy-based damage variable varies with axial strain in the shape of “S,” and approaches one more closely than that based on density at the final failure period. The research in the rock failure from the perspective of energy may further understand the mechanical behavior of rocks.

Abstract Detection and anti‐detection with multispectral camouflage are of pivotal importance, while suffer from significant challenges due to the inherent contradiction between detection and anti‐detection and conflict microwave and infrared (IR) stealth mechanisms. Here, a strategy is proposed to asymmetrically control transmitted microwave wavefront under radar‐IR bi‐stealth scheme using composite metasurface. It is engineered composed of infrared stealth layer (IRSL), microwave absorbing layer (MAL), and asymmetric microwave transmissive structure (AMTS) with polarization conversion from top to bottom. Therein, IR emissivity, microwave reflectivity, and transmissivity are simultaneously modulated by elaborately designing the filling ratio of ITO square patches on IRSL, which ensures both efficient microwave transmission and IR camouflage. Furthermore, full‐polarized backward microwave stealth is achieved on MAL by transmitting and absorbing microwaves under x‐ and y‐ polarization, respectively, while forward wavefront is controlled by precise curvature phase compensation on AMTS according to ray‐tracing technology. For verification, a proof‐of‐concept metadevice is numerically and experimentally characterized. Both results coincide well, demonstrating spiral detective wavefront manipulation under y‐polarized forward wave excitation while effective reduction of radar cross section within 8–18 GHz and low IR emissivity (

Conformal metasurface antenna embedded on the platform with an arbitrary shape is of great significance for communication systems in practical applications. Herein, a convenient design strategy for conformal transmissive metasurface antenna with arbitrary cylinder surface is presented. First, a novel‐phase compensation concept for curved surface is inspired by ray‐tracing technique. Then, by using arc differentiation and numerical integration, the meta‐atoms’ coordinates calculation method is analyzed for arbitrary cylindrical surface. Next, the electromagnetic responses of planar and curved transmissive meta‐atoms are discussed, and conformal metasurfaces in single‐quadratic surfaces are simulated to validate the feasibility of the design strategy. Finally, for potential applications, three combined quadratics conformal metasurface antennas with capabilities of beam focusing, beam deflecting, and vortex generation are designed and measured. It is indicated in the results that the three conformal metasurface antennas with combined quadratic cylinder surfaces can transform the spherical wave efficiently into the plane wave, deflected beam, and vortex beam, respectively, verifying the validity of the designs. The convenient strategy has good generality and flexibility because it is applicable to arbitrary cylindrical metasurface with a specific alignment function, which has promising perspective in practical applications, and offers a novel approach to design conformal antennas without changing aerodynamic shapes of platforms.

In this paper, a broadband bi-functional metasurface is presented with capabilities of generating vortex beam for y-polarization and reducing the backward radar cross section (RCS) for x-polarization. With careful optimization, a meta-atom is first designed to control reflection phases for orthogonally polarized wave independently. Then, an integrated phase profile is employed to convert y-polarized spherical wavefront into a vortex spiral one, shaping a vortex high gain beam in the far-field region. By arranging a checkerboard-like phase profile onto the surface for x-polarization, the reflected wave in the backward direction will be canceled, consequently leading to the backward RCS reduction for x-polarization. Combining the above-mentioned cases into a whole, a compact bi-functional metasurface is designed, simulated, physically implemented, and finally measured. In good agreement with the simulated results, the measured ones show that the RCS reduction of 10 dB for x-polarization in comparison with a same-sized metallic plate can be realized over a 67.7 % frequency bandwidth (9-18.2 GHz). Besides, high-efficiency vortex beam conversion effect for y-polarization over a broad range of 11.2-18.2 GHz (47.6%) can also be observed from the measured results.

Catalytic asymmetric [2 + 4] cycloadditions of 3-vinylindoles with ortho-quinone methides and their precursors were carried out in the presence of chiral phosphoric acid to afford a series of indole-containing chroman derivatives with structural diversity in overall high yields (up to 98%), good diastereoselectivities (up to 93:7 dr) and moderate to excellent enantioselectivities (up to 98% ee). This approach not only enriches the chemistry of catalytic asymmetric cycloadditions involving 3-vinylindoles but is also useful for synthesizing chiral chroman derivatives.

The electronic structure and thermoelectric (TE) properties of PbSxTe1−x(x = 0.25, 0.5, and 0.75) solid solution have been studied by combining the first-principles calculations and semi-classical Boltzmann theory. The special quasirandom structure (SQS) method is used to model the solid solutions of PbSxTe1−x, which can produce reasonable electronic structures with respect to experimental results. The maximum ɀT value can reach 1.67 for p-type PbS0.75Te0.25 and 1.30 for PbS0.5Te0.5 at 800 K, respectively. The performance of p-type PbSxTe1−x is superior to the n-type ones, mainly attributed to the higher effective mass of the carriers. The ɀT values for PbSxTe1−x solid solutions are higher than that of pure PbTe and PbS, in which the combination of low thermal conductivity and high power factor play important roles. [ABSTRACT FROM AUTHOR]

The electronic structure and thermoelectric (TE) properties of Mg2GexSn1−x (x = 0.25, 0.50, 0.75) solid solutions are investigated by first-principles calculations and semi-classical Boltzmann theory. The special quasi-random structure (SQS) is used to model the solid solutions, which can produce reasonable band gaps with respect to experimental results. The n-type solid solutions have an excellent thermoelectric performance with maximum zT values exceeding 2.0, where the combination of low lattice thermal conductivity and high power factor (PF) plays an important role. These values are higher than those of pure Mg2Sn and Mg2Ge. The p-type solid solutions are inferior to the n-type ones, mainly due to the much lower PF. The maximum zT value of 0.62 is predicted for p-type Mg2Ge0.25Sn0.75 at 800 K. The results suggest that the n-type Mg2GexSn1−x solid solutions are promising mid-temperature TE materials. [ABSTRACT FROM AUTHOR]