We improve the surface of graphene by atomic layer deposition (ALD) without the assistance of a transition layer or surface functionalization. By controlling gas-solid physical adsorption between water molecules and graphene through the optimization of pre-H2O treatment and two-step temperature growth, we directly grew uniform and compact Al2O3 films onto graphene by ALD. Al2O3 films, deposited with 4-cycle pre-H2O treatment and 100-200 °C two-step growing process, presented a relative permittivity of 7.2 and a breakdown critical electrical field of 9 MV/cm. Moreover, the deposition of Al2O3 did not introduce any detective defects or disorders in graphene.

Effects of chitosan coating with cinnamon oil on the physiological attributes and preservation quality of China jujube fruits during storage at 4°C for 60 days were investigated. Results indicated that weight loss and decay of jujube fruits were significantly reduced by chitosan-oil coating during the period of 60-day storage, which also exhibited a quite beneficial effect on maintaining the sensory quality for jujube fruits. Meanwhile, the contents of vitamin C and titratable acid decreased to 3.08 mg·g−1 and 0.342% for the fruits treated by chitosan-oil coating (1.0% + 0.10%), respectively. Polyphenol oxidase, superoxide dismutase, and peroxidase activities were 13.40 U·g−1, 14.53 U·g−1, and 63.6 U·g−1 at the end of storage, respectively. The contents of total soluble phenolics and MDA were 34.51 mg·g−1 and 19.43 μmol·g−1 for the combined coating treated samples and control fruits, respectively. These results suggested that the chitosan-oil coating might be recognized as one efficiency technology on the preservation quality of jujube fruits during the storage time.

The effect of different coating materials on the biological characteristics and stability of microencapsulated Lactobacillus acidophilus was investigated. Results indicated that the surface and microstructure of microcapsules were significantly affected by the type of coating material. A complex carrier could provide protection for L. acidophilus cells against simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Cell survivals give higher counts with 2.1 and 3.72 logarithmic cycle reduction found in microencapsulated L. acidophilus with complex wall materials and free cells after exposure to SIF for 180 min, respectively. Furthermore, at the high temperatures investigated, a higher cell survival rate in microcapsules embedded with complex materials was found than for free cells and those with other materials. Cell counts were reduced to 8.16, 7.17, and 6.42 log CFU mL À1 and 5.86, 4.29, and 2.32 log CFU mL À1 for microcapsules with complex materials and free cells treated at 50, 60 or 70 C for 20 min, respectively. Stability was also improved compared to free cells at refrigerated temperatures. For the cells that were released from microcapsules, the counts increased with a prolonged incubation time.Moreover, the survival rate of cells with microencapsulation was better than that of free cells at high concentrations of bile salt. Results showed that for improving protection against deleterious factors, complex materials might be a better choice for the preparation of microcapsules.

temporarily deform during birth to enable the infant's head to pass through the narrow birth canal. After birth, this flexibility is no longer needed, but instead a rigid state is desired to protect the sensitive brain, and thus the material properties of the skull change, closing the skull into a rigid bone. Likewise, variable-stiffness components are of great interest to achieve morphing robotics and in bionics. [1,2] In medicine and tissue engineering, variable stiffness is also of fundamental importance, especially when interacting with the surrounding microenvironment. For instance, compliant hydrogels and scaffolds can be used to facilitate insertion and adaptation during surgery, and thereafter the transplanted materials harden to reconstruct the function and mechanical properties of the injured hard tissue. [2,3] A number of variable-stiffness actuators have been developed, but they mainly combine components with different stiffness and non-dynamic properties. [2,4] Novel functional materials are decisive for the development of new variable-stiffness systems and functionality. Bioinspired and biohybrid materials that integrate biological components [5] (e.g., cells, enzymes, phospholipids) would enable the development of unprecedented variable-stiffness systems and functionality.We here report a biohybrid variable-stiffness actuator that creates its own bone. The biohybrid actuator uses the electroactive polymer Polypyrrole (PPy) as the mechanically active component and is combined with alginate (Alg) hydrogels functionalized with cell-derived plasma membrane nanofragments (PMNFs) as the bioinducing source for mineralization and stiffening of the gel layer. This allows the development of unique soft-to-hard variable-stiffness actuators for potential applications in soft (micro-)robotics and bone tissue engineering (Figure 1). PMNFs were shown to be the nucleation sites for bone formation in vivo. [6] PMNFs comprise phospholipids and bone formation-related enzymes, including tissue non-specific alkaline phosphatase (TNALP), which promote the hydrolysis of phosphate-containing substrates and release free phosphate ions that further participate in the formation of calcium-phosphate minerals [e.g., amorphous calcium phosphate (ACP), hydroxyapatite (HAp)]. [7] Previous reports also demonstrated the ability of the PMNFs to promote rapid mineralization in vitro in just 2 to 3 days, [6,8] while live cells or recombinant TNALP require at least 2 to 3 weeks. [9] The PMNFs are assumed to maintain the membrane-bound enzymes and proteins Inspired by the dynamic process of initial bone development, in which a soft tissue turns into a solid load-bearing structure, the fabrication, optimization, and characterization of bioinduced variable-stiffness actuators that can morph in various shapes and change their properties from soft to rigid are hereby presented. Bilayer devices are prepared by combining the electromechanically active properties of polypyrrole with the compliant behavior of alginate gels that are uniquely ...

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AlN films are grown on AlGaN/GaN by PEALD. High-temperature annealing promotes complete nitridation of AlN film, and causes AlN to form a semiconductor-like structure.

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