Performance improvement of zinc oxide photoanode-based dye-sensitized solar cells by multi-walled carbon nanotube

Unique electrical and surface-to-volume properties of carbon nanotubes have made these conductive molecules highly attractive in many applications. In this work, the influence of multi-walled carbon nanotubes into a zinc oxide active layer of dye-sensitized zinc oxide solar cell has been investigated. With this method, a significant improvement in the performance of the solar cell has been achieved. Compared to the typical zinc oxide photoelectrochemical cells, the photocurrent-voltage characteristics of the fabricated cell containing 0.05 percent by weight of carbon nanotubes in the metal oxide film displayed a higher short-circuit photocurrent, consequently caused an increase of the solar-to-electricity conversion efficiency by a factor of approximately 1.4. Further increase of the conductive carbon material resulted in a decrease of the energy conversion of the photovoltaic cell. The enhancement of the energy conversion at this optimum carbon nanotube loading may be attributed to the dye-adsorption ability and the electrochemical activity of the composite photoanodes. The fabricated photovoltaic cells with the highest efficiency exhibited the maximum dye adsorption intensity and the minimum charge transfer resistance, as measured by ultraviolet-visible spectroscopy and electrochemical impedance spectroscopy, respectively.     

<Emphasis Type="Italic">Trans</Emphasis> Fatty Acid-Induced NF-κB Activation Does Not Induce Insulin Resistance in Cultured Murine Skeletal Muscle Cells

Long-chain saturated fatty acids such as palmitic acid induce insulin resistance and NF-κB activation in skeletal muscle cells. Here we investigated the effects of long-chain fatty acid (FA) saturation and configuration on NF-κB activity and insulin sensitivity in cultured skeletal muscle cells. Of all tested unsaturated FAs, only elaidic acid (3-fold), cis9,trans11-CLA (3-fold) and trans10,cis12-CLA (13-fold) increased NF-κB transactivation in myotubes. This was not accompanied by decreased insulin sensitivity (measured as insulin-induced glucose uptake and GLUT4 translocation). We therefore conclude that FA-induced NF-κB activation is not sufficient for the induction of insulin resistance in skeletal muscle cells.     

Synthesis and preliminary characterization of novel naphthalene bisimide based copolymers

Here we report the synthesis and preliminary characterization of three novel conjugated 2,6-(naphthalene-1,4,5,8-tetracarboxylic-N,N′-dialkyldiimide) based copolymers with π-conjugation throughout the main chain. Two (PNATF and PNTTOF) copolymers were polymerized through Suzuki type cross-coupling reactions, the other (PNATT3) via a Stille-type reaction. The modifications of the side chain on the naphthalene bisimide unit and the thiophene contents in the polymer backbone were investigated. The structures of these polymers were confirmed by NMR. PNATF and PNTTOF could be dissolved in common solvents such as toluene, CHCl₃ and 1,2-dichlorobenzene. The optical spectra of the three copolymers revealed that they had two strong absorption bands at 386–394 and 600–670 nm. The photoluminescence spectra of PNATF and PNTTOF showed a weak red emission. The band gap values of the copolymer films determined from electrochemical and optical measurements were in good agreement, ranging between 1.58–1.88 and 1.53–1.69 eV, respectively. From these data we suggest these three copolymers are worthy of further investigation as potential candidates for applications in electronic devices.     

Kinetics for Describing the Creaming of Protein-Stabilized O/W Emulsions by Multiple Light Scattering

In the present work, new kinetics to describe the creaming stability of oil-in-water emulsions determined by backscattering measurements （BS） is proposed. The emulsions assayed exhibited a different backscattering profiles regarding creaming destabilization hyperbolic and sigmoid one. Hyperbolic behavior can be described by a second order kinetics, where k_h could be equaled to a rate constant that describes the creaming process and its values would indicate the stability of emulsions. While for the sigmoid BS pattern, kinetics with two terms, is adequate to describe the creaming process in contrast to kinetics previously reported in the literature. The kh value has the same meaning as before, and ks indicates the delaying effect on the creaming rate.