Catalysis direction selective asymmetric polymerization in chiral liquid crystal medium

A series of optically inactive aryl isocyanide derivatives were polymerized with an achiral nickel catalyst (Ni(II)Cl₂) in a cholesteric liquid crystal (CLC) medium. The polymers synthesized from ortho-substituted phenyl isocyanide monomers in CLC phase show optical activity even though they have no chiral carbons. The Cotton effects of these polymers suggest that main chains of the polymers formed predominantly one-handed helical conformation. One-handed chiral environment in reaction state provided by CLC medium allows the formation of the polymers. The helical sense of the polymers is controllable by choice of (R)- or (S)-CLC as reaction solvent, though the monomer is same.     

Performance of pigeons (Columba livia) on maze problems presented on the LCD screen: In search for preplanning ability in an avian species.

The authors examined how pigeons (Columba livia) perform on 2-dimensional maze tasks on the LCD monitor and whether the pigeons preplan the solution before starting to solve the maze. After training 4 pigeons to move a red square (the target) to a blue square (the goal) by pecking, the authors exposed them to a variety of detour tasks having lines as a barrier. A preview phase was introduced, during which the pigeons were not allowed to peck at the monitor. Results of a set of experiments suggest that our pigeons successfully learned to solve these tasks, that they came to take an efficient strategy as the barriers became complex, and that they possibly preplan its solution, at least on familiar, well-practiced tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Formation of single-walled carbon nanotube thin films enriched with semiconducting nanotubes and their application in photoelectrochemical devices

Single-walled carbon nanotube (SWCNT) thin films, containing a high-density of semiconducting nanotubes, were obtained by a gel-centrifugation method. The agarose gel concentration and centrifugation force were optimized to achieve high semiconducting and metallic nanotube separation efficiency at 0.1 wt% agarose gel and 18,000g. The thickness of SWCNT films can be precisely controlled from 65 to 260 nm with adjustable transparency. These SWCNT films were applied in photoelectrochemical devices. Photocurrents generated by semiconducting SWCNT enriched films are 15-35% higher than those by unsorted SWCNT films. This is because of reducing exciton recombination channels as a result of the removal of metallic nanotubes. Thinner films generate higher photocurrents because charge carriers have less chances going in metallic nanotubes for recombination, before they can reach electrodes. Developing more scalable and selective methods for high purity semiconducting SWCNTs is important to further improve the photocurrent generation efficiency by using SWCNT-based photoelectrochemical devices.     

Electrochemical properties of graphite electrode in propylene carbonate-based electrolytes containing lithium and calcium ions

Electrochemical properties of graphite electrode are studied in propylene carbonate (PC) electrolytes containing both LiN(SO₂CF₃)₂ and Ca(N(SO₂CF₃)₂)₂ salts, and the influence of the salt concentrations on the intercalation/de-intercalation properties of graphite electrode is clarified. In the higher concentration electrolytes, reversible lithium-ion intercalation/de-intercalation at graphite electrode takes place. In contrast, only the exfoliation of graphite occurs in the lower concentration electrolytes. The effect of the salt concentrations on the electrochemical properties of graphite is discussed.     

Time-resolved conformational analysis of poly(ethylene oxide) during the hydrogelling process

We investigated a drastic conformation change in a poly(ethylene oxide) (PEO) chain during the hydrogelation process using infrared (IR) spectroscopy and quantum chemical calculations (QCCs). Time-resolved in situ IR spectra of the hydrogelling process of a semi-crystalline PEO solid were measured using a flow-through cell. It was found from the time-resolved IR study that gauche conformations around the C-C bonds in the crystalline phase PEO chain maintain their conformations even after hydrogelation, while at least half of the trans conformations around the C-O bonds change into gauche conformations upon hydrogelling. With regard to the phenomena of these conformation changes after contacting water, the destruction and hydrogelation of the crystalline phase around the C-C bonds of the hydrophobic moiety occur prior to changes around the C-O bonds of the hydrophilic moiety. In addition, our QCC confirmed that the stable hydration structure of bridging water, wherein the two hydroxyl groups in a water molecule donate hydrogen bonds to every other ether oxygen atoms in the PEO chain.     

Motion blur reduction with triangular waveform emission and optimized enhance filter

Degradation of moving image quality by motion blur on hold‐type displays is a well‐known issue. In order to reduce motion blur, a number of driving methods, such as a higher frame rate and a shorter temporal aperture, have been proposed. Methods to reduce motion blur by means of signal processing as a precompensation method have also been proposed. In these methods, however, hold emission that emits light at a constant intensity during a frame is used. Since the spatial frequency response of the hold emission in a moving picture has a null point, the effectiveness of precompensation methods is limited to the lower‐spatial frequency domain. A triangular waveform emission has been investigated, and it has a higher spatial frequency response than hold emission. In the present paper, we calculated an optimized enhancement filter for the triangular waveform emission as a precompensation method and demonstrated its effectiveness for reducing motion blur by using the triangular waveform emission and the optimized enhancement filter. As a result, the optimized enhancement filter reduced motion blur and suppressed distortion that emerged when using a conventional enhancement filter.     

A novel anisotropic conducting thin film having a conducting and insulating layered structure

Electrochemical polymerization of Langmuir-Blodgett multilayers of amphiphilic pyrrole derivatives resulted in novel anisotropic conducting thin films (T. Iyoda, M. Ando, T. Kaneko, A. Ohtani, T. Shimidzu and K. Honda, Tetrahedron Lett., 27 (1986) 5633). They have an alternating layered structure of a conducting polypyrrole layer and an insulating alkyl chain layer. This paper deals with their syntheses, characterizations and functionalities.     

Fabrication of miniature Clark oxygen sensor integrated with microstructure

A miniature Clark-type oxygen sensor has been integrated with a microstructure using a novel fabrication technique. The oxygen chip consists of a glass substrate with a three-electrode configuration, which is separated and connected by a groove, and a poly(dimethylsiloxane) (PDMS) container with an immobilized PDMS oxygen-permeable membrane. The assembly of the different substrates only uses the O₂ plasma bonding technique, and the fabrication temperatures do not exceed 95 °C. Characteristics of the miniature sensor include the fastest response time of 6.8 s, good linearity with a correlation coefficient of 0.995, and a long lifetime of at least 60 h. The present miniature Clark oxygen sensor can be readily integrated with a microfluidic system to form a μ-TAS.     

High‐frequency drive of high‐Xe‐content PDPs for high efficiency and low‐voltage performance

Abstract— It has been well known that the luminous efficiency of PDPs can be improved by increasing the Xe content in the panel. For instance, the efficiency is improved by a factor 1.7 when the Xe content is increased from 3.5% to 30%. The sustain pulse voltage, however, increases from 180 to 230 V by a factor 1.3. It was found that the increase in the sustain pulse voltage can be suppressed by increasing the sustain pulse frequency. The high‐frequency operation further increases the luminous efficiency. If the Xe content is increased from 3.5% to 30% and the drive pulse frequency is increased from 147 to 313 kHz, the luminous efficiency becomes 2.7 times higher and the luminance 4.5 times higher. Furthermore, the increase in the sustain pulse voltage is suppressed 1.1 times, from 180 to 200 V. A mechanism of attaining high efficiency and low‐voltage performance can be considered as follows. A train of pulses is applied during a sustain period. As the sustain pulse frequency is increased, the pulse repetition rate becomes faster and a percentage of the space charge created by the previous pulse remains until the following pulse is applied. Due to the priming effect of these space charge, the discharge current build‐up becomes faster, the width of the discharge current becomes narrower, ion‐heating loss is reduced, and the effective electron temperature is optimized so that Xe atoms are excited more efficiently. The intensity of Xe 147‐nm radiation, dominant in low‐pressure Xe dis‐charges, saturates with respect to electron density due to plasma saturation. This determines the high end of the sustain pulse frequency.     

Nanocrystal quantum dot-conjugated anti-myeloperoxidase antibody as the detector of activated neutrophils

Fluorescent nanocrystal quantum dots (QDs) have been applied to a wide range of biological studies by taking advantage of their fluorescence properties. Here we show that QDs conjugated with antibody against neutrophil peroxidase, myeloperoxidase (MPO). We designed a novel method to conjugate QDs to antibody without losing any antibody function including their antigen recognizing and Fc-receptor binding activities. When we applied anti-MPO antibody (Ab) with conventional organic probes in the case of immunostaining of living cells, the antibodies lost their fluorescence because of MPO enzymic activity to produce reactive oxygen species. Our QD-conjugated anti-MPO (alpha-MPO-QDs) can detect MPO on the surface of activated neutrophils. In addition, anti-MPO-QDs did not react to the inactivated neutrophils. In conclusion, we demonstrated that antibody visualized the expression of MPO on the neutrophil surface after stimulation with proinflammatory cytokines. Taken together, these techniques have the possibility that QDs can reveal the activation of neutrophils by immunostaining and flow cytometric analysis as a powerful tool for diagnosis of the neutrophil activation in vitro.