Synthesis and Electrochemical Characterization of Nitrate-Doped Polypyrrole/Ag Nanowire Nanorods as Supercapacitors.

Polypyrrole (PPy)-capped silver nanowire (Ag NW) nanomaterials (core-shell rod-shaped Ag NW@PPy) were synthesized using a one-port suspension polymerization technique. The thickness of the PPy layer on the 50 nm thickness/15 µm length Ag NW was effectively controlled to 10, 40, 50, and 60 nm. Thin films cast from one-dimensional conductive Ag NW@PPy formed a three-dimensional (3D) conductive porous network structure and provided excellent electrochemical performance. The 3D Ag NW@PPy network can significantly reduce the internal resistance of the electrode and maintain structural stability. As a result, a high specific capacitance of 625 F/g at a scan rate of 1 mV/s was obtained from the 3D porous Ag NW@PPy composite film. The cycling performance over a long period exceeding 10,000 cycles was also evaluated. We expect that our core-shell-structured Ag NW@PPy composites and their 3D porous structure network films can be applied as electrochemical materials for the design and manufacturing of supercapacitors and other energy storage devices.

Flexible Sensor Film Based on Rod-Shaped SWCNT-Polypyrrole Nanocomposite for Acetone Gas Detection.

A nanocomposite rod-shaped structure with a single-walled carbon nanotube (SWCNT) embedded in polypyrrole (PPy) doped with nonafluorobutanesulfonic acid (C4F), SWCNT/C4F-PPy, was synthesized using emulsion polymerization. The hybrid ink was then directly coated on a polyimide film interdigitated with the Cu/Ni/Au electrodes via a screen-printing technique to create a flexible film sensor. The sensor film showed a response of 1.72% at 25 °C/atmospheric pressure when acetone gas of 5 ppm was injected, which corresponds to almost 95% compared to the Si wafer-based array interdigitated with the Au electrode. Additionally, C4F was used as a hydrophobic dopant of PPy to improve the stability of humidity and to produce a highly sensitive film-type gas sensor that provides stable detection even in humid conditions.

Acetone Gas Sensor Based on SWCNT/Polypyrrole/Phenyllactic Acid Nanocomposite with High Sensitivity and Humidity Stability.

We synthesized core-shell-shaped nanocomposites composed of a single-walled carbon nanotube (SWCNT) and heptadecafluorooctanesulfonic acid-doped polypyrrole (C8F-doped-PPy)/phenyllatic acid (PLA), i.e., C8F-doped-PPy/PLA@SWCNT, for detecting acetone gas with high sensitivity and humidity stability. The obtained nanocomposites have the structural features of a sensing material as a C8F-doped-PPy layer surrounding a single-stranded SWCNT, and a PLA layer on the outer surface of the PPy as a specific sensing layer for acetone. PLA was chemically combined with the positively charged PPy backbone and provided the ability to reliably detect acetone gas at concentrations as low as 50 ppb even at 25 °C, which is required for medical diagnoses via human breath analysis. When C8F was contained in the pyrrole monomer in a ratio of 0.1 mol, it was able to stably detect an effective signal in a relative humidity (RH) of 0-80% range.

Electrically conductive epoxy nanocomposites with expanded graphite/carbon nanotube hybrid fillers prepared by direct hybridization.

Carbon nanotubes (CNTs) are generally used to promote the electrical conductivity of the polymer nanocomposites. However, in spite of their superior properties, CNT's high cost has limited their commercial application, so far. Thus, the development of hybrid carbon nanomaterials (CNMs) composed of CNTs and cheaper CNMs such as carbon fibers (CFs), expanded graphites (EGs), and graphene nanoplatelets (GNPs) is important in terms of reducing the cost of CNT-based fillers. In this study, we prepared EG/CNT hybrid fillers via direct CNT synthesis on the EG support using modified combustion method and thermal chemical vapor deposition (CVD) method, and investigated the electrical conductivity of the expoxy nanocomposite with EG/CNT hybrid fillers. The epoxy nanocomposites with EG/CNT hybrid fillers at 20 wt% filler loading showed 260% and 170% electrical conductivity enhancement in comparison with the EG and the simply mixed EG and CNT fillers, respectively. Our approach provides various applications including electromagnetic interference (EMI) shielding materials, thermal interface materials (TIMs), and reinforced nanocomposites.

Comprehensive assessment of P21 polymorphisms and lung cancer risk.

The purpose of this study is to comprehensively evaluate potential functional polymorphisms in the P21 gene in relation to the risk of lung cancer. We first determined the frequencies of P21 polymorphisms in 27 healthy Koreans, and then examined three polymorphisms (-2266G > A, S31R, and IVS2 + 16G > C), based on their frequencies and haplotype-tagging status, in a case-control study. Individuals with at least one -2266A allele were at a significantly decreased risk of lung cancer compared with those harboring the -2266 GG genotype [adjusted odds ratio (OR) = 0.71, 95% confidence interval (CI) = 0.53-0.95, P = 0.02). The haplotypes (ht2-4) carrying 31R or IVS2 + 16C alleles were associated with a significantly decreased risk of lung cancer compared with the haplotype 31S/IVS2 + 16G, which carried wild-type alleles at both loci (adjusted OR = 0.65, 95% CI = 0.50-0.83, P = 0.007)]. When the -2266A allele and ht2-4 were considered to be protective alleles, the risk of lung cancer decreased in a dose-dependent manner as the number of protective alleles increased (P = 0.0002). These results suggest that a combined analysis of these three P21 polymorphisms might better predict the risk of lung cancer than the analysis of a single polymorphism.

Polymorphisms in the caspase-8 gene and the risk of lung cancer.

Caspase-8 (CASP-8) is an initiator CASP in the cell death receptor-mediated apoptotic pathway, and plays an important role in the development of cancer. Polymorphisms and their haplotypes in the CASP-8 gene can result in alterations in CASP-8 expression and/or activity, thereby modulating the susceptibility to lung cancer. To test this hypothesis, we examined the association of -678_-673delAGTAAG (-678del) and IVS12-19G-->A polymorphisms and their haplotypes with the risk of lung cancer in a Korean population. The CASP-8 genotypes were determined in 432 lung cancer patients and 432 healthy age- and gender-matched control subjects. The distributions of the CASP-8 -678del and IVS12-19G-->A genotypes were not significantly different between the overall lung cancer cases and the controls. When the cases were categorized by tumor histology, however, the IVS12-19 AA genotype and the combined IVS12-19 GA + AA genotype were associated with a significantly decreased risk of small cell carcinoma (SmCC) compared with the IVS12-19 GG genotype [adjusted odds ratio (OR) = 0.14, 95% confidence interval (CI) = 0.03-0.64, P = 0.01; and adjusted OR = 0.56, 95% CI = 0.33-0.96, P = 0.03, respectively]. Consistent with the genotyping analyses, the -678del-/IVS12-19A haplotype containing 94% of the IVS12-19A allele in the study population was associated with a significantly decreased risk of SmCC compared with the -678del-/IVS12-19G (adjusted OR = 0.58, 95% CI = 0.36-0.93, P = 0.023, and Pc = 0.046). These findings suggest that the CASP-8 gene may contribute to an inherited predisposition to SmCC of the lung.

Statin inhibits interferon-gamma-induced expression of intercellular adhesion molecule-1 (ICAM-1) in vascular endothelial and smooth muscle cells.

Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, known as statins, are widely used for primary and secondary prevention of coronary artery atherosclerosis. Pathogenesis of atherosclerosis is multistep processes where transendothelial migration of various leukocytes including monocytes is a crucial step. Interferon-gamma (IFN-gamma) contributes in this process by activating macrophages and T-lymphocytes, and by inducing adhesion molecules in vascular endothelial and smooth muscle cells. In this study we investigated the expression of intercellular cell adhesion molecule-1 (ICAM-1) in transformed endothelial cell line ECV304 cells as influenced by lovastatin, tumor necrosis factor-alpha (TNF-alpha) and IFN-gamma. Results show that lovastatin suppresses expression of ICAM-1 by inhibiting the IFN-gamma-induced extracellular signal-regulated kinase (ERK) p44/p42-STAT1 signaling pathway. In cells treated with lovastatin and IFN-gamma, ICAM-1 was expressed at a lower level than in cells treated with IFN-gamma alone. However, lovastatin does not reduce TNF-alpha induced expression of ICAM-1. A similar result was observed in cells treated with the MEKK inhibitor PD98059 and IFN-gamma. Cis-acting DNA sequence elements were identified in the 5'-flanking region of the ICAM-1 promoter that mediate inhibition by lovastatin; these sequences map to the IFN-gamma activated site which also binds the STAT1 homodimer. However, lovastatin did not inhibit IFN-gamma-mediated induction of the Y701 phosphorylated form of STAT1. But lovastatin does inhibit the IFN-gamma-mediated phosphorylation of ERK1/ERK2 (T202/Y204) and S727 phosphorylation of STAT1. TNF-alpha does not induce phosphorylation of ERK1/ERK2 and S727 in ECV304 and smooth muscle cells. The results provide the evidences that statins may have beneficial effects by inhibiting IFN-gamma action in atherosclerotic process