Wide electrochemical window at the interface between water and a hydrophobic room-temperature ionic liquid of tetrakis[3,5-bis(trifluoromethyl)phenyl]borate

Ionic liquids composed of a hydrophobic anion, tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (TFPB-), and various aromatic and aliphatic ammonium have been prepared. TFPB salts of N-octadecylisoquinolinium (C18Iq+) and trioctylmethylammonium (TOMA+) show low melting points of 31 and 36 degrees C, respectively, whereas TFPB-based ionic liquids of 1-alkyl-3-methylimidazolium with the alkyl chain length of 5-12 show melting points lower than 90 degrees C. The [C(18)Iq][TFPB]|water (W) and [TOMA][TFPB]|W interfaces have the polarized potential window (ppw) of 0.8 V at 56 degrees C, which is twice as wide as the ppw at the interface between W and room-temperature ionic liquids of bis(perfluoroalkylsulfonyl)imide so far reported. The extension of the ppw by more than 0.4 V to the positive direction enables voltammetric measurements of the ion transfer of relatively hydrophobic anions such as bis(trifluoromethylsulfonyl)imide and bis(pentafluoroethylsulfonyl)imide and of hydrophilic cations such as tetraethylammonium and acetylcholine ions.     

Gene expression property of high-density three-dimensional tissue of HepG2 cells formed in radial-flow bioreactor

In our previous study, we examined three-dimensional culture using 5-ml radial-flow bioreactor (RFB) and showed that genes encoding cell cycle related proteins were suppressed in a stable phase. In this study, we analyzed the gene expression profiles of RFB-cultivated HepG2 cells and found that vascular endothelial growth factor (VEGF) production was strongly induced in the stable phase compared with the growth phase or static two-dimensional culture. When human umbilical vein endothelial cells (HUVECs) were grown under the conditioned medium of the stable phase, it was found that the formation of new blood vessels was induced in the angiogenesis model. DNA microarray analysis showed that the expression levels of both genes related to cell cycle arrest and which are known as tumor markers have increased in the stable phase. This result suggests that HepG2 cells in the stable phase maintain an active tumor phenotype. In addition, the expression of genes induced in the hypoxic condition was also induced in the stable phase. When the culture was carried out under a higher dissolved oxygen (DO) concentration, VEGF production did not decrease significantly and the new blood-vessel-forming ability of the conditioned medium was not suppressed. This suggests that the induction of VEGF production in a stable phase is not affected by DO during the tested level. These results suggest that the RFB cell culture system may be used to assess tumor progression mechanism under three-dimensional condition in vitro.     

Inhibitory Effects of Saururus chinensis Extract on Receptor for Advanced Glycation End-Products-Dependent Inflammation and Diabetes-Induced Dysregulation of Vasodilation

Advanced glycation end-products (AGEs) and the receptor for AGEs (RAGE) are implicated in inflammatory reactions and vascular complications in diabetes. Signaling pathways downstream of RAGE are involved in NF-κB activation. In this study, we examined whether ethanol extracts of Saururus chinensis (Lour.) Baill. (SE) could affect RAGE signaling and vascular relaxation in streptozotocin (STZ)-induced diabetic rats. Treatment with SE inhibited AGEs-modified bovine serum albumin (AGEs-BSA)-elicited activation of NF-κB and could compete with AGEs-BSA binding to RAGE in a dose-dependent manner. Tumor necrosis factor-α (TNF-α) secretion induced by lipopolysaccharide (LPS)—a RAGE ligand—was also reduced by SE treatment in wild-type Ager^+/+ mice as well as in cultured peritoneal macrophages from Ager^+/+ mice but not in Ager^−/− mice. SE administration significantly ameliorated diabetes-related dysregulation of acetylcholine-mediated vascular relaxation in STZ-induced diabetic rats. These results suggest that SE would inhibit RAGE signaling and would be useful for the improvement of vascular endothelial dysfunction in diabetes.     

Facilitated transfer of alkali-metal cations by dibenzo-18-crown-6 across the electrochemically polarized interface between an aqueous solution and a hydrophobic room-temperature ionic liquid

The facilitated transfer of alkali metal cations (Li+, Na+, K+, Rb+, Cs+) by dibenzo-18-crown-6 (DB18C6) across the electrochemically polarizable interface between an aqueous solution (W) and a hydrophobic ionic liquid, N-octadecylisoquinolinium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate ([C18Iq][TFPB]), has been studied using cyclic voltammetry at the interface formed at the tip of a micropipet. In cyclic voltammograms (CVs), the current due to the facilitated transfer of the cations by DB18C6 from W to [C18Iq][TFPB] can be measured within the polarized potential window of the [C(18)Iq][TFPB]|W interface. The stoichiometry of the complexes in [C18Iq][TFPB] for Li+, Na+, K+, and Rb+ are found to be 1:1 while for the Cs+ transfer both 1:1 and 1:2 complexes are likely to be formed. The formation constants of the 1:1 complexes for Li+, Na+, K+, and Rb+ in [C18Iq][TFPB], , evaluated from CVs are log = 5.0, 7.0, 8.2, and 7.3, respectively. The value for K+ is 1 order of magnitude greater than that for Na+. This higher selectivity of DB18C6 to K+ over Na+ in [C18Iq][TFPB] compared with that in molecular solvents suggests that the RTIL provides a unique solvation environment for the complexations of DB18C6 with the ions.     

Development of three-dimensional reactor analysis code system for accelerator-driven system,ADS3D and its application with subcriticality adjustment mechanism

In order to perform the parametric survey for an accelerator-driven system (ADS) core with the subcriticality adjustment mechanism, a new calculation code system, ADS3D, was developed on MARBLE which is a comprehensive and versatile framework for reactor analysis. The application of ADS3D was also demonstrated on the neutronics design of ADS operated by control rod (CR) movement. Through the neutronics calculation, it was shown that the maximum proton beam current was decreased from 20.5 to 11.6 mA due to the switch from beam-operated to CR-operated core.     

Synthesis of Red-Light-Responsive Pheophorbide-a Tryptamine Conjugated Photosensitizers for Photodynamic Therapy

Six methyl pheophorbide-a derivatives were prepared by linking a tryptamine side chain at the C-13 ¹ , C-15 ² and C-17 ³ positions of pheophorbide-a. P repared conjugates were characterized and evaluated for their photocytotoxicity against A549 cells. The conjugate 6 a with strong absorption at 413 nm (Soret band), 663–671 nm (Q bands) and comparable fluorescence quantum yield (0.26) was found to exhibit significant cytotoxicity (659 nM). Molecular integration of pheophorbide-a and tryptamines showed synergistic effects as the most potent conjugate 6 a was identified with enhanced photocytotoxicity when compared to methyl pheophorbide-a. T he conjugate 6 a was smoothly taken up by A549 cells and exhibited intracellular localization predominantly to lysosome in the cytoplasm. Upon photoirradiation 6 a generated singlet oxygen to show potent cytotoxicity toward A549 cells.     

Design of freely configurable safety light curtain using hemispherical mirrors

Safety light curtains provide reliable and cost‐effective protection against access into hazardous points or areas. However, in practice, peopl still need to adjust the light detection element accurately in order to receive the safe amount of irradiating laser light. In our proposed system, we utilized light emitting diodes (LEDs) as the light source, and designed two hemispherical mirrors to receive the LED light, and used PSoC microcomputer to determine the threshold voltage value. Compared with recent market products, the proposed system is freely configurable, and with no dead zone detection. In addition, compared to the laser light, the LED light has the advantages of no radiation, small electropult, low‐cost, and high efficiency. After conducting sufficient experiments, the proposed system has been found to successfully detect the intruder with 100% recognition rate, which can meet the needs of industrialization. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.