Surface modification of poly(ethylene terephthalate) by plasma polymerization of poly(ethylene glycol)

Poly(ethylene glycol) (PEG) was ‘polymerized’ onto poly(ethylene terephthalate) (PET) surface by radio frequency (RF) plasma polymerization of PEG (average molecular weight 200 Da) at a monomer vapour partial pressure of 10 Pa. Thin films strongly adherent onto PET could be produced by this method. The modified surface was characterized by infra red (IR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), cross-cut test, contact angle measurements and static platelet adhesion studies. The modified surface, believed to be extensively cross-linked, however showed all the chemical characteristics of PEG. The surface was found to be highly hydrophilic as evidenced by an interfacial free energy of about 0.7 dynes/cm. AFM studies showed that the surface of the modified PET became smooth by the plasma polymerized deposition. Static platelet adhesion studies using platelet rich plasma (PRP) showed considerably reduced adhesion of platelets onto the modified surface by SEM. Plasma ‘polymerization’ of a polymer such as PEG onto substrates may be a novel and interesting strategy to prepare PEG-like surfaces on a variety of substrates since the technique allows the formation of thin, pin-hole free, strongly adherent films on a variety of substrates.     

Visualizing vitreous using quantum dots as imaging agents

Vitreous is transparent tissue located between the lens and the retina of the eye, thus, difficult to look at by even ophthalmological microscope. But vitreous is connected with some sight-threatening eye diseases, for example, retinal detachment, macular hole, epi-retinal membrane, and so forth. Quantum dots (QDs) have been applied to a wide range of biological studies by taking advantage of their fluorescence properties. We established a novel technique of aqueous colloidal QD (ACQD) as a vitreous lesion detector. When compared with some conventional dyes used for clinical situation, i.e. fluorescein, indocyanine green, and triamcinolone acetonide, ACQD exerted a higher performance to detect a Weiss Ring. Furthermore ACQD is also effective to perform vitrectomy, an eye surgery to cut and eliminate vitreous. Some functional structures in vitreous are detected clearly when ACQD was injected into an enucleated porcine eye. We demonstrated that ACQD enabled any ophthalmic surgeon to perform vitrectomy reliably, easily, and more safely. Taken together, the ACQD-oriented vitreous staining system will promote ophthalmological science, and it will raise the cure rate of eye diseases     

Interleukin-18 protects mice against acute herpes simplex virus type 1 infection

We examined the effects of interleukin-18 (IL-18) in a mouse model of acute intraperitoneal infection with herpes simplex virus type 1 (HSV-1). Four days of treatment with IL-18 (from 2 days before infection to 1 day after infection) improved the survival rate of BALB/c, BALB/c nude, and BALB/c SCID mice, suggesting innate immunity. One day after infection, HSV-1 titers were higher in the peritoneal washing fluid of control BALB/c mice than in that of IL-18-treated mice. A genetic deficiency of gamma interferon (IFN-gamma), however, diminished the survival rate and the inhibition of HSV-1 growth at the injection site in the mice. Anti-asialo GM1 treatment had no influence on the protective effect of IL-18 in infected mice. IL-18 augmented IFN-gamma release in vitro by peritoneal cells from uninfected mice, while no appreciable IFN-gamma production was found in uninfected mice administered IL-18. Although IFN-gamma has the ability to induce nitric oxide (NO) production by various types of cells, administration of the NO synthase inhibitor NG-monomethyl-L-arginine resulted in superficial loss of the improved survival, but there was no influence on the inhibition of HSV-1 replication at the injection site in IL-18-treated mice. Based on these results, we propose that IFN-gamma produced before HSV-1 infection plays a key role as one of the IL-18-promoted protection mechanisms and that neither NK cells nor NO plays this role.     

Basic investigation for life assessment technology of modified 9Cr–1Mo steel

In order to develop life assessment techniques for aged components made of modified 9Cr–1Mo steel, specimens were artificially deteriorated by aging, creep and fatigue tests at elevated temperatures, and associated changes in the microstructure and mechanical properties were examined. It was observed that aging resulted in formation of Laves phase causing a decrease in toughness. The creep damage in base metal could be correlated with decrease in hardness, while creep damage in weldments could be correlated with the area fraction and density of creep voids. Creep rupture in weldments occurred in the fine-grained heat affected zone by the formation and growth of creep voids. The fatigue damage in base metal correlated to the maximum length of a crack among micro-cracks initiated during fatigue cycles.     

An inverse analysis of two-phase Stefan problems using imaginary heat sources

This paper presents a new methodology for the inverse analysis of time-dependent two-phase Stefan problems. The problem considered here is that of determining the time dependence of a phase-change interface at several observed temperatures. In our method, imaginary heat sources are arranged in an imaginary domain and then the phase-change interface is identified as the isothermal surface at the melting temperature by controlling the imaginary heat source intensities. Using delta-function imaginary heat sources and their corresponding Green functions, which are pre-calculated numerically, it is shown that the phase-change interface is determined non-iteratively at each time step. We offer numerical examples to demonstrate the capability of the proposed method. © 1998 Scripta Technica, Heat Trans Jpn Res, 27(3): 179–191, 1998     

Development of flexible polymer blend films from advanced copna resin and nylon 6

The application of advanced polycondensed fused polynuclear aromatic (COPNA) resin to a material for flexible printed wiring boards was studied in this work. To give flexibility to the advanced COPNA resin, a polymer blend technology was introduced. Nylon 6 was selected from the nominated blend polymers with advanced COPNA resin because of sufficient compatibility between the advanced COPNA resin and the amino groups. The polymer blend film, consisting of advanced COPNA resin and nylon 6 prepared at a blend fraction of 50/50 (COPNA/nylon 6), exhibited sufficient flexibility for printed wiring boards, and exhibited attractive properties of T_g at 158°C and a dielectric constant at 3.6. Morphological analysis was also carried out by transmission electron microscopy to the blends. Phase-separated structures were observed in entire systems of fully cured films because of crystallinity of the nylon 6, but sufficient compatibility for practical uses was observed in both the 30/70 and 50/50 systems. The compatibility became poor with an increase of the advanced COPNA resin fraction. © 1996 John Wiley & Sons, Inc.     

Characteristic long-chain fatty acid of Pleurocybella porrigens

As part of an investigation on the chemical constituents and contaminants of the basidiomycete Pleurocybella porrigens (Japanese name: Sugihiratake), we analyzed the UV-detected constituents of this mushroom using HPLC. One of the major UV peaks detected was isolated and identified as a-eleostearic acid, a long-chain fatty acid with a conjugated triene moiety, based on the results of spectroscopic methods. alpha-Eleostearic acid was concluded to be a characteristic fatty acid of P. porrigens, because it was not detected in eight other edible mushrooms examined. Free long-chain fatty acids in P. porrigens and other edible mushrooms were analyzed by HPLC after derivatization with acidic 2-nitrophenylhydrazine hydrochloride. Oleic acid was the main fatty acid in P. porrigens, and saturated long-chain fatty acids such as linoleic acid, palmitic acid, and stearic acid, together with a-eleostearic acid, were also detected.     

High quality epitaxial ZnO films grown on solid-phase crystallized buffer layers

High quality epitaxial ZnO films on sapphire (110) plane have been fabricated on ZnO homo-buffer layers crystallized via solid-phase epitaxially (SPE). The SPE-ZnO films are fabricated by annealing of amorphous ZnON (a-ZnON) films deposited by RF magnetron sputtering. During annealing, the a-ZnON films are oxidized and converted to ZnO crystal. X-ray diffraction (XRD) analysis shows that the resultant films are epitaxially grown on the sapphire substrates. By using the SPE-ZnO films as homo-buffer layers, the ZnO films with high crystallinity, which are deposited by RF magnetron sputtering, are fabricated. The full width at half-maximum of XRD patterns for 2θ-ω and ω scan of (002) plane are 0.094° and 0.12°, respectively, being significantly small compared with 0.24° and 0.55° for the films without buffer layers. Thus utilizing SPE buffer layers is very promising to obtain epitaxial ZnO films with high crystallinity.     

Challenges to the Carbon Dioxide Capture and Storage (CCS) Technology

Carbon dioxide Capture and Storage (CCS) technology, which is one of the technologies against global warming, applied to the separation and capture of CO₂ gas and finally storage underground is attracting attention. There are several technologies being developed for CO₂ separation and capture, namely the chemical absorption method, physical absorption method, adsorbing separation method and membrane separation method. These are being developed to apply to postcombustion capture, oxyfuel postcombustion capture, etc. With regard to the CO₂ storage technologies, the method of injection into an aquifer is being developed as the major one, and studies on issues for actual technical application are being conducted in the form of engineering study on the assumed model area. In this report, our expectations toward actual application of the CCS technology, the trends of the CCS technology and other related matters are introduced. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.