Preparation and Electrochemical Properties of Polyaniline Composite Electrodes Prepared by In-Situ Polymerization in Hydrous Ruthenium Oxide Dispersed Aqueous Solution

Polyaniline (PANI)/ruthenium oxide (RuO2) composites were prepared by a chemical oxidation polymerization with various amount of hydrous RuO2. In the PANI/RuO2 composites, RuO2 particles were surrounded by PANI. The morphology and structure of the PANI/RuO2 composites were examined by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Analysis by TEM revealed that the aggregations of the composites were increased with the amounts of hydrous RuO2. Electrochemical performances of prepared composites were characterized by cyclic voltammetry (CV). The composites prepared with 20 wt% of hydrous RuO2 per aniline monomer showed the highest specific capacitance of 710 F/g at 5 mV/s among the prepared composites. However, the specific capacitance of the composites with excess amounts of hydrous RuO2 is lower than the highest one. The large aggregation of RuO2 particles prevents the participation in electrochemical reaction due to the long pathway from the electrolyte and a decrease of effective surface area.

Preparation and Electrochemical Properties of Polyaniline Composite Electrodes Prepared by In-Situ Polymerization in Hydrous Ruthenium Oxide Dispersed Aqueous Solution

Polyaniline (PANI)/ruthenium oxide (RuO2) composites were prepared by a chemical oxidation polymerization with various amount of hydrous RuO2. In the PANI/RuO2 composites, RuO2 particles were surrounded by PANI. The morphology and structure of the PANI/RuO2 composites were examined by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Analysis by TEM revealed that the aggregations of the composites were increased with the amounts of hydrous RuO2. Electrochemical performances of prepared composites were characterized by cyclic voltammetry (CV). The composites prepared with 20 wt% of hydrous RuO2 per aniline monomer showed the highest specific capacitance of 710 F/g at 5 mV/s among the prepared composites. However, the specific capacitance of the composites with excess amounts of hydrous RuO2 is lower than the highest one. The large aggregation of RuO2 particles prevents the participation in electrochemical reaction due to the long pathway from the electrolyte and a decrease of effective surface area.

Extending single mode performance of all-solid large-mode-area single trench fiber

We report a novel "single trench fiber" design for mode area scaling of the fundamental mode while offering effective single mode operation for a compact fiber laser device. This fiber design allows very high suppression of the higher order modes by offering high loss and power delocalization. It has the advantages of low cost and easy fabrication thanks to all solid fiber design, cylindrical symmetry, and higher refractive index of core as that of the cladding. A Yb-doped single trench fiber with a 40 µm core diameter has been fabricated from modified chemical vapor deposition process in conjunction with solution-doping offering an effective mode area of as large as ~1,000 µm(2) at 1,060 nm for the bend radius of 20 cm. Detailed characterizations confirm a robust single mode behavior of the fiber. Comparative analysis with other fiber designs shows significant performance enhancement of effective single mode operation suitable for fiber laser applications.

Few-mode multi-element fiber amplifier for mode division multiplexing

We experimentally demonstrate a few-moded cladding-pumped multi-element fiber amplifier, comprising 4 Er/Yb co-doped signal fibers and 1 multimode pump-delivery fiber all of which are drawn together in a common polymer coating, providing a total spatial path multiplicity of 12. An average WDM signal gain of 18.3 dB and differential modal gain of 1.1 dB were achieved in the spectral range of 1542-1560 nm.

Cladding pumped few-mode EDFA for mode division multiplexed transmission

We experimentally demonstrate a few-mode erbium doped fiber amplifier (FM-EDFA) supporting 6 spatial modes with a cladding pumped architecture. Average modal gains are measured to be >20dB between 1534nm-1565nm with a differential modal gain of ~3dB among the mode groups and noise figures of 6-7dB. The cladding pumped FM-EDFA offers a cost effective alternative to core-pumped variant as low cost, high power multimode pumps can be used, and offers performance, scalability and simplicity to FM-EDFA design.

Synthesis of amorphous carbon materials for lithium secondary batteries

A new and effective approach to enhance electrochemical properties of amorphous carbons is presented. Phosphorus-doped amorphous carbons have been prepared by incorporating a phosphorus compound into petroleum cokes and carbonizing them at 850 degrees C for 1 h. It was observed that reversible capacity of amorphous carbons was greatly improved by incorporating a very small amount of phosphorus (around 1%), implying that extra lithium-storage-sites were created by phosphorus doping. In addition, the phosphorus-doped amorphous carbons showed outstanding rate capability (205 mA h/g at 5 C) and excellent capacity retention of about 90% after 50 cycles, comparable to that of undoped carbons. Very interestingly, a trade-off relation between capacity and cycle property, which is very common in electrode materials, was not found in the phosphorus-doped amorphous carbons.

Rubi Fructus (Rubus coreanus) activates the expression of thermogenic genes in vivo and in vitro

OBJECTIVE

To investigate the anti-obesity effect of Rubi Fructus (RF) extract using brown adipose tissue (BAT) and primary brown preadipocytes in vivo and in vitro.

METHODS

Male C57BL/6 J mice (n=5 per group) were fed a high-fat diet (HFD) for 10 weeks with or without RF. Brown preadipocytes from the interscapular BAT of mice (age, post-natal days 1-3) were cultured with differentiation media (DM) including isobutylmethylxanthine, dexamethasone, T3, indomethacin and insulin with or without RF.

RESULTS

In HFD-induced obese C57BL/6 J mice, long-term RF treatment significantly reduced weight gain as well as the weights of the white adipose tissue, liver and spleen. Serum levels of total cholesterol and low-density lipoprotein cholesterol were also reduced in the HFD group which received RF treatment. Furthermore, RF induced thermogenic-, adipogenic- and mitochondria-related gene expressions in BAT. In primary brown adipocytes, RF effectively stimulated the expressions of thermogenic- and mitochondria-related genes. In addition, to examine whether LIPIN1, a regulator of adipocyte differentiation, is regulated by RF, Lipin1 small interfering RNA (siRNA) and RF were pretreated in primary brown adipocytes. Pretreatment with Lipin1 siRNA and RF downregulated the DM-induced expression levels of thermogenic- and mitochondria-related genes. Moreover, RF markedly upregulated AMP-activated protein kinase. Our study shows that RF is capable of stimulating the differentiation of brown adipocytes through the modulation of thermogenic genes.

CONCLUSIONS

This study demonstrates that RF prevents the development of obesity in mice fed with a HFD and that it is also capable of stimulating the differentiation of brown adipocytes through the modulation of thermogenic genes, which suggests that RF has potential as a therapeutic application for the treatment or prevention of obesity.