Hydrogenation of poly(vinyl cinnamate) thin layer

Hydrogenation of poly(vinyl cinnamate) was performed with RhH(CO)(PPh₃)₃ catalyst with intent to clarify the photoalignment mechanism of liquid crystals on poly(vinyl cinnamate) alignment layer. The hydrogenated cinnamate side group shows the characteristic peaks at 2.9 ppm and 2.5 ppm in ¹H-NMR spectrum, and a decreasing peak at 280 nm in UV spectrum. This reaction can reveal the role of dimerized or residual cinnamate groups in the applications of the polymeric layer for electronic devices.     

Experimental Study of Islanding‐Prevention Method by Harmonic Injection Synchronized with Exciting Current Harmonics of Pole Transformer

As distributed generators (DGs) such as photovoltaic (PV) systems are increasingly used in distribution systems, quick prevention of islanding caused by power system failure is essential to assure electrical safety. Various islanding protection methods have been used practically, but the conventional active systems tend to increase the detection time, because mutual interference occurs between active signals due to asynchronous states. A new active islanding detection method, the frequency feedback method with step reactive power injection, also has the possibility of extending the detection time in the so‐called perfect balance area (PBA). Thus we propose a novel method of islanding‐prevention by harmonic injection synchronized with the exciting current harmonics of the pole transformer. We performed an experimental study using prototype inverters equipped with the proposed method. We have shown the feasibility of detecting islanding quickly and reliably, even if the islanding state is in the PBA. The experimental results demonstrate that mutual interference does not occur due to asynchronous states between active signals, and also that the proposed method is applicable to islanding detection system in clustered installation of PV systems.     

Compositions,flavour and antiradical properties of products from subcritical water treatment of raw Isada krill

Comparative analysis of subcritical water (SCW) treatment and ambient pressure boiling one of raw Isada krill was performed for the nutritive, flavour and antiradical properties of krill extracts and residues as well as the molecular mass and odour intensity of the extract. SCW treatment was performed for 10 min in a batch‐type vessel in the temperature range of 100–240 °C, using a 1:1 weight ratio of raw krill to water. Higher protein and lipid contents were obtained by SCW treatment relative to boiling. The lipid content of the SCW extracts increased with increasing treatment temperature. Protein was the main component in these extracts, and the highest protein content was achieved by SCW treatment at 200 °C. High‐molecular‐mass species decomposed under SCW treatment at high temperatures with consequent generation of smaller molecules. The antiradical activity of the SCW extract, determined by DPPH and ABTS assays, increased with increasing treatment temperature. The krill extracts and residues exhibited shrimp‐like flavour, and the most desirable flavour was obtained by SCW treatment at 140 °C or 160 °C for 10 min. The treatment would be applicable for the production of seasonings from Isada krill.     

Alkynylboranes: A Practical Approach by Zinc‐Catalyzed Dehydrogenative Coupling of Terminal Alkynes with 1,8‐Naphthalenediaminatoborane

Under zinc Lewis acid catalysis, terminal alkynes coupled dehydrogenatively with 1,8‐naphthalenediaminatoborane [HB(dan)]. It is important to note that the resulting alkynylboranes with an C(sp) B(dan) bond are isolable by column chromatography on silica gel (SiO₂) and are usable as coupling partners for palladium‐ and copper‐catalyzed cross‐coupling reactions with (hetero)aryl halides.

     

Preparation and characterization of stimuli-resistible hydrogels nano-coated with polyelectrolyte multilayer films

Alginate (ALG) hydrogels were nano-coated with polyelectrolyte multilayer (PEM) films composed of poly(diallyldimethyl ammonium chloride) (PDDA) and poly(sodium 4-styrenesulfonate) (PSS). Non- and nano-coated ALG hydrogels were immersed into salt solutions (pH 6, ionic strength: 0.01 M), and the swelling behavior of these ALG hydrogels was observed by optical microscopy. The increases in the diameter of the 10-step coated ALG hydrogels were one fourth or less than that of the non-coated hydrogels. These results indicate that the characteristics of nano-coated ALG hydrogels remain unchanged independent of how the external environment is changed (e.g., pH, ionic strength). Consequently, tolerant ionic hydrogels may be prepared by the nano-coating of hydrogel surfaces with PEM films and may be useful for technological and biomedical applications.     

Controlled release of drugs from gradient hydrogels for high-throughput analysis of cell-drug interactions

In this paper, we report a method to fabricate microengineered hydrogels that contain a concentration gradient of a drug for high-throughput analysis of cell-drug interactions. A microfluidic gradient generator was used to create a concentration gradient of okadaic acid (OA) as a model drug within poly(ethylene glycol) diacrylate hydrogels. These hydrogels were then incubated with MC3T3-E1 cell seeded glass slides to investigate the cell viability through the spatially controlled release of OA. The drug was released from the hydrogel in a gradient manner and induced a gradient of the cell viability. The drug concentration gradient containing hydrogels developed in this study have the potential to be used for drug discovery and diagnostics applications due to their ability to simultaneously test the effects of different concentrations of various chemicals.     

High-hydrostatic-pressure treatment impairs actin cables and budding in Saccharomyces cerevisiae

We previously reported that the postgrowth of Escherichia coli K-12 after high-hydrostatic-pressure treatment (HPT) as moderate as 75 MPa for 30 min at 37 degrees C induced the formation of elongated cells due to an HPT-induced disorder in FtsZ ring formation, which is essential for cell division. Because an FtsZ ring is known as a bacterial cytoskeleton, we examined the effect of HPT on a eukaryotic cytoskeleton, such as actin cables (long bundles of actin filaments), of Saccharomyces cerevisiae. We found that actin cables disappeared after HPT (100 MPa) and were not reorganized until 3.5 h of growth after HPT. As long as actin cables disappeared, budding did not start. We also demonstrated that the in vitro polymerization of actin monomers was highly sensitive to HPT.     

Effect of high pressure carbon dioxide on the clumping of the bacterial spores

The formation of spore clumps of Bacillus coagulans and Bacillus licheniformis during high-pressure carbon dioxide treatment (HCT) was investigated. As the treatment time increased, the number of spore clumps increased. After 120 min, single spore decreased to 20-35% of the population. Addition of a surfactant decreased the hydrophobicity of spore surface and increased both the number of single spores and the rate of inactivation ratio of B. coagulans and B. licheniformis spores.     

Harmonic analysis of the output voltage of a third‐harmonic‐injected inverter for LSM drives

The superconducting magnetic leviation railway system (MAGLEV) under development in Japan uses pulse‐width‐modulation (PWM) inverter for driving a linear synchronous motor (LSM). The inverter output voltage contains nonnegligible harmonics which cause harmonic resonances in the LSM system, and therefore harmonics of the output voltage have been analyzed in order to control such harmonic resonances. This paper applies a third‐harmonic injection method to the inverter for the purpose of enhancing the output voltage without changing the circuit configuration. It performs harmonic analysis of the output voltage of the inverter based on the third‐harmonic injection. Validity of the harmonic analysis is verified by computer simulation. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(1): 71–78, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ).