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Novel hydrogen-selective amorphous silica membranes were developed by chemical vapor deposition (CVD) method using dimethoxydimethylsilane (DMDMS) as the silica precursor. The preparation conditions were optimized by varying the DMDMS saturated vapor concentration in the CVD reactor and the CVD time. The membrane prepared under optimized conditions demonstrated excellent hydrogen-selective performance, exhibiting a hydrogen permeance of 2.8 × 10−7 mol m−2 s−1 Pa−1 at 773 K, which is approximately three times larger when compared with silica membranes prepared with tetramethoxysilane (TMOS). And the ideal selectivity of hydrogen to nitrogen at the same temperature was 2.3 × 103. The estimation of pore size by the normalized Knudsen-based permeance (NKP) method and the structural analysis by XPS indicated that the DMDMS-derived membrane possessed a thinner active separation layer compared with the TMOS-derived membrane, while the pore size was comparable. Thus, membrane thickness was influenced by the slight difference in the chemical structures of the silica precursors, resulting in a higher hydrogen permeance. Finally, excellent hydrothermal stability of the DMDMS-derived membrane was demonstrated. • Dimethoxydimethylsilane (DMDMS) was used to develop amorphous silica membranes. • The preparation conditions for the DMDMS-derived membranes were optimized. • H 2 permeance and H 2 /N 2 at 773 K were 2.8 × 10−7 mol m−2 s−1 Pa−1 and 2.3 × 103. • The excellent H 2 -selective performance was due to the thin active separation layer. • The membrane showed an excellent hydrothermal stability. [ABSTRACT FROM AUTHOR]

A binary system of Li 2 TiO 3 –LiMnO 2 is systematically examined by joint experimental and theoretical studies as electrode materials for Li storage applications. Increase in a fraction of Li 2 TiO 3 effectively activates anionic redox, and thus holes are reversibly formed on oxygen by electrochemical oxidation. Such holes are energetically stabilized through π-type interaction with Mn t 2g orbital as suggested by theoretical calculation. However, excess enrichment of Li 2 TiO 3 fractions in this binary system results in the oxygen loss as an irreversible process on delithiation because of a non-bonding character for Ti–O bonds coupled with the formation of O–O dimers, which are chemically and electrochemically unstable species. Additionally, detailed electrochemical study clearly shows that Li migration kinetics is relatively slow, presumably coupled with low electronic conductivity. Nevertheless, nanosizing of primary particles is an effective strategy to overcome this limitation. The nanosized sample prepared by mechanical milling delivers a large reversible capacity, ∼300 mA h g−1, even at room temperature and shows much improved capacity retention. Formation and stabilization of holes for the nanosized sample are also directly evidenced by soft X-ray absorption spectroscopy. From these results, factors affecting the reversibility of anionic redox as emerging new chemistry and its possibility for energy storage applications are discussed in more details. [ABSTRACT FROM AUTHOR]

Heterotypic cell interactions are critical to achieve and maintain specific functions in many tissues and organs. We have focused on patterned structure surfaces to enable co-culture of heterotypic cells and recovery of patterned co-cultured cell sheets for applications in tissue engineering. Thermoresponsive polymers exhibiting different transition temperatures in water comprise both poly(N-isopropylacrylamide) (PIPAAm) and n-butyl methacrylate (BMA) co-grafted as side chains to PIPAAm main chains. These copolymers were surface-grafted in patterns to obtain patterned dual thermoresponsive cell culture surfaces using electron beam polymerisation method and porous metal masks. On patterned surfaces, site-selective adhesion on and growth of rat primary hepatocytes (HCs) and bovine carotid endothelial cells (ECs) allowed patterned co-culture, exploiting hydrophobic/hydrophilic surface chemistry regulated by culture temperature as the sole variable. At 27°C, seeded HCs adhered exclusively onto hydrophobic, dehydrated P(IPAAm–BMA) co-grafted domains (1-mm∅ area), but not onto neighbouring hydrated PIPAAm domains. Sequentially seeded ECs then adhered exclusively to hydrophobised PIPAAm domains upon increasing culture temperature to 37°C, achieving patterned co-cultures. Reducing culture temperature to 20°C promoted hydration of both polymer-grafted domains, permitting release of the co-cultured, patterned cell monolayers as continuous cell sheets with heterotypic cell interactions. Recovered co-cultured cell sheets can be manipulated, moved and sandwiched with other structures, providing new useful constructs both for basic cell biology research and preparation of tissue-mimicking multi-layer materials through overlaying co-cultured cell sheets. [Copyright &y& Elsevier]