Stability of and inflammatory response to silicon coated with a fluoroalkyl self-assembled monolayer in the central nervous system.

A self-assembled monolayer (SAM) of fluoroalkyl silane (FAS) (CF(3)(CF(2))(5)(CH(2))(2)SiCl(3)) was deposited on the surface of silicon wafers, aiming to enhance its stability and to reduce the inflammatory response in the central nervous system. Following implantation of the FAS SAM coated silicon in rat brains, the FAS SAM coating failed to reduce the inflammatory response of silicon, because it could not prevent the corrosion of the underlying silicon. The corrosion was hindered for the initial 10 days by the FAS SAM coating, but there was nearly no difference when compared to the uncoated silicon when the implantation periods were extended to 28 and 90 days. The FAS SAM coating was completely removed within 28 and 90 days. Meanwhile, on all the extracted uncoated and FAS SAM coated silicon wafers, there were proteinaceous substances deposited on the surfaces, and the amount of the deposits increased with exposure time.

Probing small unilamellar EggPC vesicles on mica surface by atomic force microscopy.

Sonicated small unilamellar egg yolk phosphatidylcholine (EggPC) vesicles were investigated using atomic force microscopy (AFM) imaging and force measurements. Three different topographies (convex, planar, and concave shape) of the EggPC vesicles on the mica surface were observed by tapping mode in fluid, respectively. It was found that the topography change of the vesicles could be attributed to the interaction force between the AFM tip and vesicles. Force curves between an AFM tip and an unruptured vesicle were obtained in contact mode. During approach, two breaks corresponding to the abrupt penetration of upper and lower bilayer of vesicle were exhibited in the force curve. Both breaks spanned a distance of around 4 nm close to the EggPC bilayer thickness. Based on Hertz analysis of AFM approach force curves, the Young's modulus (E) and the bending modulus (kc) for pure EggPC vesicles were measured to be (1.97 +/- 0.75) x 10(6)Pa and (0.21 +/- 0.08) x 10(-19)J, respectively. The results show that the AFM can be used to obtain good images of intact and deformed vesicles by tapping mode, as well as to probe the integrity and bilayer structure of the vesicles. AFM force curve compare favorably with other methods to measure mechanical properties of soft samples with higher spatial resolution.

A new generation of zirconia supported metal oxide catalysts for converting low grade renewable feedstocks to biodiesel.

A new class of zirconia supported mixed metal oxides (ZnO-TiO(2)-Nd(2)O(3)/ZrO(2) and ZnO-SiO(2)-Yb(2)O(3)/ZrO(2)) has demonstrated the ability to convert low quality, high free fatty acid (FFA) bio-oils into biodiesel. Pelletized catalysts of ZrO(2) supported metal oxides were prepared via a sol-gel process and tested in continuous flow packed bed reactors for up to 6 months. In a single pass, while operating at mild to moderate reaction conditions, 195 °C and 300 psi, these catalysts can perform simultaneous esterification and transesterification reactions on feedstock of 33% FFA and 67% soybean oil to achieve FAME yields higher than 90%. Catalytic activity of the ZrO(2) supported metal oxide catalysts was highly dependent on the metal oxide composition. These heterogeneous catalysts will enable biodiesel manufacturers to avoid problems inherent in homogeneous processes, such as separation and washing, corrosive conditions, and excessive methanol usage.