Insight into the relationship between catalytic trends and physicochemical properties of composite nanoparticles is essential for their rational design. Herein, a series of 3d-M (M = Mn, Fe, Co, Ni) metal hydroxidepromoted PtM(OH) x /Al 2 O 3 catalysts are developed and well characterized for establishing the catalytic HCHO oxidation reactivity trend as a function of more fundamental properties, such as hydroxyl concentration and adsorption strength. The reactivity of PtM(OH) x /Al 2 O 3 exhibits an increasing trend of Mn < Fe < Co < Ni, which is governed by their OH−M 2+δ bond strength (Ni < Co < Fe < Mn) and surface hydroxyl concentration (Mn < Fe < Co < Ni). Both PtCo(OH) x / Al 2 O 3 and PtNi(OH) x /Al 2 O 3 exhibit a (>)95% HCHO conversion and (>)100 h performance stability at 30 °C with a low 0.2 wt % Pt loading amount. The identification of these catalytic trends provides foundations for composite active sites design for HCHO oxidation and other hydroxyl-involved reactions.

It remains poorly understood if carrier hardness, elastic modulus, and contact area affect neural stem cell growth and differentiation. Tensile tests show that the elastic moduli of Tiansu and SMI silicone membranes are lower than that of an ordinary dish, while the elastic modulus of SMI silicone membrane is lower than that of Tiansu silicone membrane. Neural stem cells from the cerebral cortex of embryonic day 16 Sprague-Dawley rats were seeded onto ordinary dishes as well as Tiansu silicone membrane and SMI silicone membrane. Light microscopy showed that neural stem cells on all three carriers show improved adherence. After 7 days of differentiation, neuron specific enolase, glial fibrillary acidic protein, and myelin basic protein expression was detected by immunofluorescence. Moreover, flow cytometry revealed a higher rate of neural stem cell differentiation into astrocytes on Tiansu and SMI silicone membranes than on the ordinary dish, which was also higher on the SMI than the Tiansu silicone membrane. These findings confirm that all three cell carrier types have good biocompatibility, while SMI and Tiansu silicone membranes exhibit good mechanical homogenization. Thus, elastic modulus affects neural stem cell differentiation into various nerve cells. Within a certain range, a smaller elastic modulus results in a more obvious trend of cell differentiation into astrocytes.

We present theoretical studies for the third-order elastic constants of Mg, Be, Ti, Zn, Zr, and Cd with a hexagonal-close-packed (HCP) structure. The method of homogeneous deformation combined with first-principles total-energy calculations is employed. The deformation gradient F i j is applied to the crystal lattice vectors r i , and the elastic strain energy can be obtained from the first-principles calculation. The second- and third-order elastic constants are extracted by a polynomial fit to the calculated energy-strain results. In order to assure the accuracy of our method, we calculated the complete set of the equilibrium lattice parameters and second-order elastic constants for Mg, Be, Ti, Zn, Zr, and Cd, and our results provide better agreement with the previous calculated and experimental values. Besides, we have calculated the pressure derivatives of SOECs related to third-order elastic constants, and high-pressure effects on elastic anisotropy, ductile-to-brittle criterion, and Vickers hardness are also investigated. The results show that the hardness model H v = 1.877 k 2 G 0.585 is more appropriate than H v = 2 k 2 G 0.585 − 3 for HCP metals under high pressure.