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Tungsten (W) is considered to be a promising candidate for plasma facing materials in fusion reactors because of its high melting point, high thermal diffusivity and low sputtering yield. To investigate the multiple hydrogen (H) diffusion behaviours at the W(001) surface, molecular dynamics simulations were used to study the H distributions after diffusion of 1 ns under different conditions. The results of using different H concentrations and temperatures showed the preference of bulk to surface diffusion, and the H distribution patterns of the H/W ratio of 0·1 are analysed in detail with an ‘empty’ region near the surface. The effect of temperature on H diffusion is also investigated, which gives the highest adsorption peak at a mediate temperature of 900 K. The trapping effect of vacancies on H atoms is demonstrated at different vacancy concentrations. The effect of H embedded depth on H distribution is also investigated together with the effect of temperature, which gives an increasing trend of...

The diethyl ether extract of the stems of Schisandra pubescens Hemsl. et Wils. (Schisandraceae) was found to exhibit cytotoxic activity in vitro. However, investigations of the bioactive constituents of this plant have been very limited.Elucidation of the cytotoxic constituents of S. pubescens was performed.Repeated silica gel column chromatography and preparative TLC were used for the chemical investigation of the diethyl ether extract of S. pubescens stems. All isolates were evaluated for their in vitro cytotoxicity against A549, PC-3, KB and KBvin human cancer cell lines.Nine known compounds were obtained, including four lignans, epischisandrone (1), tigloylgomisin P (2), cagayanone (3) and (-)-gomisin L₂ (4), together with five triterpenoids, micranoic acid B (5), lancifodilactone H (6), coccinic acid (7), schisanlactone B (8) and anwuweizonic acid (9). Compounds 2-6 and 8 showed moderate to marginal cytotoxicity, with GI₅₀ values of 11.83-35.65 μM.The isolation of 1-9 from S. pubescens and the cytotoxicities of 3-6 are first reported. Compounds 2-6 and 8 could be the active principles responsible for the anticancer effects of S. pubescens.

The synthesis of new chiral monomers (M1 −M3 ) based on menthol and the corresponding polyacrylates (P1 −P3 ) is described. The chemical structures, formula and phase behaviour of the obtained monomers and polymers were characterised with FT-IR, 1H-NMR, elemental analyses, differential scanning calorimetry (DSC), polarising optical microscopy (POM) and X-ray diffraction (XRD). The effect of the mesogenic core rigidity, spacer length and menthyl steric effect on the phase behaviour of M1 −M3 and P1 −P3 is discussed. The expected mesophase of the compounds based on menthol can be obtained by inserting a flexible spacer between the mesogenic core and the terminal groups. For the chiral monomers and polyacrylates, their corresponding melting temperature (T m), glass transition temperature (T g) and clearing temperature (T i) increased with an increase of the mesogenic core rigidity; while the T m, T g and T i decreased with increasing the spacer length. M1 and P1 showed no mesophase, while M2 and M3 all revea...