New Iron(II) Complexes for Atom‐Transfer Radical Polymerization: The Ligand Design for Triazacyclononane Results in High Reactivity and Catalyst Performance

Mononuclear cordinatively unsaturated iron(II) complexes having a triazacyclononane ligand were developed as highly efficient and environmentally friendly catalysts for the atom‐transfer radical polymerization (ATRP). These iron catalysts showed high performance in the well‐controlled ATRP of styrene, methacrylates, and acrylates. The high reactivity of these catalysts led to well‐controlled polymerization and block copolymerization even with lower catalyst concentrations.     

Development of a new type micro slurry‐jet erosion (MSE) tester for evaluation of wear properties of hard thin coatings

Versatile and reliable techniques for evaluation of hard thin coatings are necessary for the development and tribological assessment of new coatings. We have proposed a new type of micro slurry‐jet erosion (MSE) test, i.e. a solid particle impact erosion test for swift evaluation of wear properties of hard thin coatings. We are using a new type of MSE test apparatus (pot type tester) that makes it possible to obtain the wear loss per unit mass of erodent, which in this test was alumina particles with an average size of 1.2 µm. Its performance was evaluated by using a Si wafer plate under various test condition. In addition, the MSE tester was demonstrated by evaluating the wear resistance of TiN on high‐speed steel substrate. The new MSE test generates highly reproducible results and is very sensitive to the quality of the coatings. Copyright © 2009 John Wiley & Sons, Ltd.     

Generation of CNTs on STM Probes Using the Simple Arc Discharge Method

We succeeded in producing carbon nanotubes (CNTs) on scanning tunneling microscope (STM) probes using the simple arc discharge method. We used STM probes with a diameter of 200 µm (500 nm in diameter at the tip), and placed them in a position 5 mm from a set of carbon electrodes between which a direct current discharge of 30 V/20 A was applied. The results of scanning electron microscopy observation confirmed that the fine particles generated included high-purity CNTs on the STM probe surface. Specifically, CNTs were generated directly on the surface of the STM probe. This study indicates that the technique is suitable for nano-analysis application in the field of nanotechnology. © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Lipase-catalyzed synthesis of arbutin cinnamate in an organic solvent and application of transesterification to stabilize plant pigments

Arbutin cinnamate was synthesized from arbutin (4-hydroxyphenyl beta-D-glucopyranoside) and vinyl cinnamate by regioselective transesterification with a bacterial lipase in acetonitrile. The product was identified by NMR and FAB-MS analyses. These spectra showed that one ester bond was formed between the primary alcohol moiety of the D-glucose of arbutin and the carboxyl residue of cinnamic acid. Furthermore, plant pigments such as isoquercitrin (quercetin 3-O-beta-D-glucopyranoside) and callistephin (pelargonidin 3-O-beta-D-glucopyranoside) were also converted to their corresponding cinnamate esters in the same manner.     

WHT-based composite motion compensated NTSC interframe directcoding

The motion compensated interframe differential pulse code modulation (DPCM) and discrete cosine transform (DCT) hybrid (MC DCT) coding was nominated as a standard scheme for component TV signals by ISO and ITU-R. However, in cases where an NTSC composite TV signal is used such as the United States and Japan, applying the MC DCT scheme with its luminance/chrominance separating and composing process causes unavoidable quality degradation. The reason for this additional process required for MC DCT is that a composite TV signal presents a “color subcarrier phase shift problem” in which the color subcarrier phase varies between a coding block and reference block according to the motion vector. In this paper, we propose a Walsh Hadamard transform (WHT)-based composite motion compensated NTSC interframe direct coding scheme. In this scheme, phase shifts of a color subcarrier and modulated chrominance components between a coding block and reference block can be effectively compensated by a simple process of coefficient permutation and polarity changes of several pairs of WHT coefficients to which 100% of the subcarrier energy and most of the modulated chrominance component's energy are packed. In the motion compensated DCT scheme, however, the energy of the color subcarrier and modulated chrominance components are spread over too many coefficients and a pair-based coefficient handling rule is not given to solve this problem. This paper demonstrates that the proposed scheme provides higher coding performance for a composite NTSC signal than does the motion compensated DCT scheme with its luminance/chrominance separating and composing process     

Microscale Contacting of Two Immiscible Liquid Droplets to Measure Interfacial Tension

In various microfluidic devices, surface tension and interfacial tension values are necessary to analyze the fluid behavior in microchannels, and evaluating the values of interfacial tension is especially important for gas–liquid and liquid–liquid flows. A pendant drop method is commonly used to measure the interfacial tension value; however, the pendant drop method requires strict accuracy in measuring the droplet size when the droplet has a nonspherical shape, as well as an accurate value of the density difference between the two liquids. In this work, a new measurement method called the “liquid bridge-inducing microscale contact method” has been developed in which the interfacial tension can be obtained from the bridging of two liquid droplets extruded from opposing ends of glass capillary tubes or formed on the ends of round metal rods. By measuring the radii of curvature of each liquid surface and interface, we calculate the Laplace pressure on the surface and interface, and derive the interfacial tension value using the Laplace equation. The results show that the values of interfacial tension obtained from the two methods are approximately the same and that the liquid bridge-inducing microscale contact method is capable of accurate interfacial tension measurements.     

Involvement of Hydrogen Peroxide in Safingol-Induced Endonuclease G-Mediated Apoptosis of Squamous Cell Carcinoma Cells

Safingol, a L-threo-dihydrosphingosine, induced the nuclear translocation of a mitochondrial apoptogenic mediator—endonuclease G (endo G)—and apoptosis of human oral squamous cell carcinoma (SCC) cells. Upstream mediators remain largely unknown. The levels of hydrogen peroxide (H₂O₂) in cultured oral SCC cells were measured. Treatment with safingol increased intracellular H₂O₂ levels but not extracellular H₂O₂ levels, indicating the production of H₂O₂. The cell killing effect of safingol and H₂O₂ was diminished in the presence of reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC). Dual staining of cells with annexin V and propidium iodide (PI) revealed that apoptotic cell death occurred by treatment with H₂O₂ and safingol. The number of apoptotic cells was reduced in the presence of NAC. In untreated cells, endo G distributed in the cytoplasm and an association of endo G with mitochondria was observed. After treatment with H₂O₂ and safingol, endo G was distributed to the nucleus and cytoplasm, indicating the nuclear translocation of the mitochondrial factor. NAC prevented the increase of apoptotic cells and the translocation of endo G. Knock down of endo G diminished the cell killing effect of H₂O₂ and safingol. These results suggest that H₂O₂ is involved in the endo G-mediated apoptosis of oral SCC cells by safingol.     

Application of bioinformatics for DNA microarray data to bioscience, bioengineering and medical fields

In the 1990s, DNA microarray or DNA chip as a novel biological experimental technology was developed, which enables the comprehensive measurement of the expression levels of hundreds of genes, simultaneously. Using this technique, a comprehensive understanding of the cell can be achieved. However, because even simple life forms, such as microorganisms, have more than a thousand kinds of genes, the data from a DNA chip cannot be analyzed without statistical and informational technology. Bioinformatics is the interdisciplinary research field integrating molecular biology with informatics, and it is expected to have a huge impact on the bioscientific, bioengineering and medical fields. There are many techniques in bioinformatics for the analysis of DNA microarray data; however, these are mainly divided into fold-change analysis, clustering, classification, genetic network analysis, and simulation. In this review, these techniques are briefly explained by using some examples.