New technique for the fabrication of conductive polymer/insulating polymer composite films

The electrochemical polymerization of pyrrole on an ITO (indium‐tin oxide)‐coated glass electrode with an insulating film of poly(vinyl alcohol), PVA, produces a flexible composite polymer film with electrical, optical, and electrochemical properties very similar to polypyrrole (PPy). The rate of electrochemical polymerization depends on the diffusion of the electrolyte across the PVA film to the ITO electrode. In particular, hydrophilic solvents easily penetrate into the PVA film. By applying this new process, we demonstrate a unique method of forming electrically conductive patterns in PVA film. It will be possible to develop electrodes for electrical stimulation of the nervous system using a conducting polymer, PPy. By a similar technique we have fabricated poly(3,4‐ethylenedioxythiophene), PEDOT/PVA, composite films and have investigated their electrochemical basic properties. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(4): 1–8, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21055     

Dispersion Stability of O/W Emulsions with Different Oil Contents Under Various Freezing and Thawing Conditions

Freezing and thawing of oil‐in‐water (O/W) emulsion‐type foods bring about oil–water separation and deterioration; hence, the effects of freezing and thawing conditions on the destabilization of O/W emulsions were examined. The freezing rate and thawing temperature hardly affected the stability of the O/W emulsion. O/W emulsions having different oil fractions were stored at temperatures ranging from –30 to –20 °C and then thawed. The stability after thawing depended on the storage temperature, irrespective of the oil fraction of the emulsion. A good correlation was found between the time at which the stability began to decrease and the time taken for the oil to crystalize. These results indicated that the dominant cause for the destabilization of the O/W emulsion during freezing and thawing is the crystallization of the oil phase and that the effects of the freezing and thawing rates on the stability are insignificant.     

New fabrication technique of conductive polymer/insulating polymer composite films and evaluation of biocompatibility in neuron cultures

Poly(vinyl alcohol), PVA, produces a flexible composite polymer film with electrical, optical and electrochemical properties very similar to those of polypyrrole (PPy). The rate of electrochemical polymerization depends on the diffusion rate of the electrolyte across the PVA film to the indium tin oxide (ITO) electrode. In particular, a solvent with a hydrophilic nature easily penetrates into the PVA film. By applying this new process, we demonstrate a unique method of forming an electrically conductive pattern in PVA film. It will be possible to develop electrodes for electrical stimulation of the nervous system using the conducting polymer, PPy. Then, by applying a similar technique, we fabricated poly(3,4-ethylenedioxythiophene), PEDOT/PVA, composite films and investigated their basic electrochemical properties. Moreover, in this study, in order to develop a novel cell-culture system which makes it possible to communicate with cultured cells, fibroblasts were cultured on PPy- and PEDOT-coated ITO conductive glass plates for 7 days. The result reveals that the PPy and PEDOT films support the secretory functions of the cells cultured on its surface. The PPy- and PEDOT-coated electrodes may be useful to culture the cells on.     

Central Nervous System Stimulants Limit Caffeine Transport at the Blood–Cerebrospinal Fluid Barrier

Caffeine, a common ingredient in energy drinks, crosses the blood–brain barrier easily, but the kinetics of caffeine across the blood–cerebrospinal fluid barrier (BCSFB) has not been investigated. Therefore, 127 autopsy cases (Group A, 30 patients, stimulant-detected group; and Group B, 97 patients, no stimulant detected group) were examined. In addition, a BCSFB model was constructed using human vascular endothelial cells and human choroid plexus epithelial cells separated by a filter, and the kinetics of caffeine in the BCSFB and the effects of 4-aminopyridine (4-AP), a neuroexcitatory agent, were studied. Caffeine concentrations in right heart blood (Rs) and cerebrospinal fluid (CSF) were compared in the autopsy cases: caffeine concentrations were higher in Rs than CSF in Group A compared to Group B. In the BCSFB model, caffeine and 4-AP were added to the upper layer, and the concentration in the lower layer of choroid plexus epithelial cells was measured. The CSF caffeine concentration was suppressed, depending on the 4-AP concentration. Histomorphological examination suggested that choroid plexus epithelial cells were involved in inhibiting the efflux of caffeine to the CSF. Thus, the simultaneous presence of stimulants and caffeine inhibits caffeine transfer across the BCSFB.     

Evaluation of adhesively bonded joint strength of CFRP with laser treatment

Pulsed laser surface treatment was applied to carbon fiber-reinforced plastics (CFRPs) to enhance the work efficiency as well as to establish the stable clean process of surface pre-treatment during the bonding process of CFRP structures. Surface analyses were conducted to CFRP treated by various laser conditions in order to find the optimal laser process. Adhesively bonded specimens were fabricated using CFRPs subjected to laser treatment, and adhesive lap shear strength of CFRPs bonded with adhesive films was evaluated compared with the abrasive paper treatment. Surface conditions, adhesive strength, and adhesive fracture mode depended on the treatment parameters, and adhesive strength similar to abrasive paper treatment could be obtained in the specimens with appropriate laser treatment. It was concluded that laser surface treatment can be applied to the surface treatment process of CFRP bonded structures.     

Colocalization of MCM8 and MCM7 with proteins involved in distinct aspects of DNA replication

Minichromosome maintenance (MCM) proteins are essential for DNA replication in eukaryotes. A subcomplex of the MCM2-7 family members, initially characterized in yeast, is thought to serve as a eukaryotic DNA replicative helicase. MCM8 is a new family member, not present in yeast, which may function alone or with other family members in aspects of DNA metabolism, including replication initiation and elongation. Through the use of chromatin immunoprecipitation, we find that MCM8, like MCM7, colocalizes on a specific DNA segment of the c-MYC replication initiation zone (c-MYC replicator) with Cdc6, a protein potentially involved in loading MCM proteins onto DNA. The association between MCM8 and MCM7 peaks in mid G1, at the time of assembly of the prereplication complex. The association of both MCM proteins with Cdc6, however, continues even after DNA replication is complete. We also find that MCM8 colocalizes at the c-MYC replicator with chromatin-bound Cdk2. Our data indicate that any role MCM8 may play in elongation is likely to be discontinuous, in its association with DNA, from a potential role in initiation. Using immunogold electron microscopy we show that MCM8 and MCM7 differ in spatial relation to RPA70 during S phase. Our data strongly suggest that MCM8 functions with other known replication proteins in processes which accompany DNA replication, especially initiation, and which are specifically adapted to suit higher eukaryotes.     

Distribution of radionuclides in surface seawater obtained by an aerial radiological survey

We investigated the distribution in seawater of anthropogenic radionuclides from the Fukushima Daiichi Nuclear Power Plant (FNPP1) as preliminary attempt using a rapid aerial radiological survey performed by the U.S. Department of Energy National Nuclear Security Administration on 18 April 2011. We found strong correlations between in-situ activities of ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs measured in surface seawater samples and gamma-ray peak count rates determined by the aerial survey (correlation coefficients were 0.89 for ¹³¹I, 0.96 for¹³⁴Cs, and 0.92 for¹³⁷Cs). The offshore area of high radionuclide activity extended south and southeast from the FNPP1. The maximum activities of ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs were 329, 650, and 599 Bq L^?1, respectively. The ¹³¹I/¹³⁷Cs ratio in surface water of the high-activity area ranged from 0.6 to 0.7. Considering the radioactive decay of ¹³¹I (half-life 8.02 d), we determined that the radionuclides in this area were directly released from FNPP1 to the ocean. We confirm that aerial radiological surveys can be effective for investigating the surface distribution of anthropogenic radionuclides in seawater. Our model reproduced the distribution pattern of radionuclides derived from the FNPP1, although results simulated by a regional ocean model were underestimated.     

Effect of moisture sorption of underwear material on clothing microclimate in a hot environment

In this study, to investigate the thermal comfort of underwear, it was experimentally evaluated how the moisture sorption of underwear material affected the transient condition on the clothing microclimate under the summer heat environment by using a perspiration thermal manikin. Three kinds of underwear with different mixed spinning rates of moisture absorbing synthetic fiber (MAS) were compared. It was shown that the higher the mixed spinning rate of MAS, the larger the decline of the humidity in the clothing was in insensible perspiration. In comparison, for PET70 with 100% cotton (COT100), though each of the official moisture regions was almost the same, the microclimate humidity declined more rapidly in COT100 and returned to the original humidity in a shorter time. The integration value of the humidity decline which returned to the original value was the same between the two materials. To show the effect of the initial condition of the material, the underwear in a moderate humid condition, which was 30^°C, 65% RH, was compared with one in a dry condition. The fall in the clothing microclimate of the humid condition was about one third that of the dry one. In sensible perspiration, though the humidity decline was seen, it returned to the original humidity faster than in the insensible condition. A temperature rise in the clothing and a temperature drop occurred as frequently as in the standard underwear during drying on the skin surface. This suggested that the endothermic reaction occurred as moisture desorbed. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20220