Preservation of the plasma ash pattern of biological specimens by subsequent coating with a plasma-polymerized thin film

A new technique for preservation of a plasma ashed pattern of a thin-sectioned biological specimen by subsequent coating of the ash with a polymer thin film deposited by plasma polymerization is described. A thin-sectioned rat liver specimen (10 μm thickness) supported by a glass slide was microincinerated in a reactor by using an oxygen glow discharge. The remaining ash was subsequently coated by a plasma polymerized thin film (4000 Å thickness) in the same plasma reactor using perfluorobutene-2 vapor as the monomer. The coated ash was mechanically strong and nonhygroscopic in ambient air so that the glass slide with the coated ash could be stored as a permanent preparation.     

A vision chip with column-level amplification of optical data signals for indoor optical wireless local area networks

We present a vision chip architecture with column-level photo-amplification of optical data signals for optical wireless local area networks (LANs) to reduce the pixel area. Based on the architecture, we have fabricated a prototype vision chip in a standard 0.8 μm bipolar complementary metal-oxide-semiconductor (BiCMOS) technology. The device offers position detection of other optical transceivers in the LAN and 4-ch concurrent high-speed optical data acquisition. A data rate of 400 Mbps was demonstrated. The pixel size was 125 μm square, which can be shrunk to smaller than around 60 μm square in 0.35 μm or more advanced BiCMOS or CMOS technologies.     

Dilute Solution Properties and Aggregation Behavior of Alternate Hetero-arm Copolymer Brushes

Alternate hetero-arm copolymer brushes were synthesized by free-radical copolymerizations of vinylbenzyl-terminated polystyrene macromonomers (PS-VB) with a methacryloyl-terminated poly(ethylene oxide) macromonomer (PEO-MA)/tin tetrachloride (SnCl(4): Lewis acid) complex. Dilute solution properties of such hetero-arm copolymer brushes were investigated by static and dynamic light scattering. Effective diffusion coefficients D(eff) for copolymer brushes possessing large aspect ratios showed almost constant values in the range of polymer concentrations 0-6x10(-3) g/cm(3). These results mean that copolymer brushes formed unimolecular structures even in a good solvent such as benzene. It was speculated from angular dependence measurements that in solution copolymer brushes take geometrically anisotropic conformations such as cylinders. To determine the phase-separated cylindrical domains of alternate copolymer brushes, we constructed large aggregates of copolymer brushes in water. Consequently, alternate copolymer brushes seemed to lead self-assemblies among phase-separated hydrophobic PS domains. Copyright 2001 Academic Press.     

Hydrophobic/superhydrophobic oxidized metal surfaces showing negligible contact angle hysteresis

The blood coagulation system relies on lipid membrane constituents to act as regulators of the coagulation process upon vascular trauma, and in particular the 2D configuration of the lipid membranes is known to efficiently catalyze enzymatic activity of blood coagulation factors. This work demonstrates a new application of a recently developed methodology to study blood coagulation at lipid membrane interfaces with the use of imaging technology. Lipid membranes with varied net charges were formed on silica supports by systematically using different combinations of lipids where neutral phosphocholine (PC) lipids were mixed with phospholipids having either positively charged ethylphosphocholine (EPC), or negatively charged phosphatidylserine (PS) headgroups. Coagulation imaging demonstrated that negatively charged SiO(2) and membrane surfaces exposing PS (obtained from liposomes containing 30% of PS) had coagulation times which were significantly shorter than those for plain PC membranes and EPC exposing membrane surfaces (obtained from liposomes containing 30% of EPC). Coagulation times decreased non-linearly with increasing negative surface charge for lipid membranes. A threshold value for shorter coagulation times was observed below a PS content of ～6%. We conclude that the lipid membranes on solid support studied with the imaging setup as presented in this study offers a flexible and non-expensive solution for coagulation studies at biological membranes. It will be interesting to extend the present study towards examining coagulation on more complex lipid-based model systems.     

Pilot-Scale Aftertreatment Using Nonthermal Plasma Reduction of Adsorbed NOx in Marine Diesel-Engine Exhaust Gas

Regulations governing marine diesel engine NO_x emissions have recently become more stringent. As it is difficult to fulfill these requirements by combustion improvements alone, effective aftertreatment technologies are needed to achieve efficient NO_x reductions. In this study, we develop an effective NO_x-reduction aftertreatment system for a marine diesel engine that employs combined nonthermal plasma (NTP) and adsorption. Compared with selective catalytic reduction, the proposed technology offers the advantages of not requiring a urea solution or harmful heavy-metal catalysts and low operating temperatures of less than 150 °C. The NO_x reduction comprises repeated adsorption and desorption flow processes using NTP combined with NO_x adsorbents made of MnO_x–CuO. High concentrations of NO_x are treated by NTP after NO_x adsorption and desorption, and this aftertreatment system demonstrates excellent energy efficiencies of 161 g(NO₂)/kWh, which fulfills the most recent International Maritime Organization emission NO_x standards in the Tier II–III regulations for 2016 and requires only 4.3 % of the engine output power.     

Piezoelectric and dielectric properties of siloxane elastomers filled with bariumtitanate

Piezoelectric elastomers were prepared from suspensions of bariumtitanate (BaTiO₃) particles in a telechelic polydimethylsiloxane (t-PDMS) by crosslinking the t-PDMS under an electric field. Crosslinking reaction was monitored by measurement of complex dielectric constant ε′ − iε″. Dielectric constant ε′ increased with increasing BaTiO₃ content, and agreed approximately with the theoretical ε′ calculated with the Maxwell–Wagner theory. Piezoelectric constant d₃₃ of the poled elastomers was measured by application of compressions in the direction of the poling field. It was found that d₃₃ was of the order of 10⁻¹¹ C/N and increased steeply with increasing content of BaTiO₃ but became almost independent of composition in the range of BaTiO₃ content from 3 to 14 vol %. To examine the effect of electric field on the aggregation structure of the particles, we observed light scattering of the suspension under an electric field, and found that the scattering pattern became anisotropic. This indicated that the particles are connected like a pearl necklace and are stretched in the direction of the poling field. The dependence of d₃₃ on the volume fraction of BaTiO₃ was explained by a model proposed by Banno. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 3065–3070, 1999     

Oenothein B in Eucalyptus Leaf Extract Suppresses Fructose Absorption in Caco-2 Cells

Inhibition of fructose absorption may suppress adiposity and adiposity-related diseases caused by fructose ingestion. Eucalyptus leaf extract (ELE) inhibits intestinal fructose absorption (but not glucose absorption); however, its active compound has not yet been identified. Therefore, we evaluated the inhibitory activity of ELE obtained from Eucalyptus globulus using an intestinal fructose permeation assay with the human intestinal epithelial cell line Caco-2. The luminal sides of a cell monolayer model cultured on membrane filters were exposed to fructose with or without the ELE. Cellular fructose permeation was evaluated by measuring the fructose concentration in the medium on the basolateral side. ELE inhibited 65% of fructose absorption at a final concentration of 1 mg/mL. Oenothein B isolated from the ELE strongly inhibited fructose absorption; the inhibition rate was 63% at a final concentration of 5 μg/mL. Oenothein B did not affect glucose absorption. In contrast, the other major constituents (i.e., gallic acid and ellagic acid) showed little fructose-inhibitory activity. To our knowledge, this is the first report that oenothein B in ELE strongly inhibits fructose absorption in vitro. ELE containing oenothein B can prevent and ameliorate obesity and other diseases caused by dietary fructose consumption.     

Dielectric studies on the dynamics of polymer chains in various environments

Stockmayer's type-A chain such as cis-polyisoprene (PI) having dipole moments aligned parallel to the chain contour exhibits slow dielectric response, reflecting fluctuation of the end-to-end vector of the chain ( dielectric normal modes ). This article intends to review our own work on dielectric spectroscopy using PI as a probe for studying dynamics of large scale motion of the probe chain in binary blends with polybutadiene (PB) and in block copolymers with PB or with polystyrene. Through such studies we were able to see the features of polymer chain dynamics in various environments: Rouse-Zimm-like dynamics in overlapping-but-unentangled regimes, reptation with and without accompanying constraint release, behaviour of a subchain incorporated into block copolymers with miscible segments, and dynamics of polymer brushes in strongly segregating block copolymers in bulk and in solutions.     

A new crosslinkable polyphenol from a renewable resource

Cardanol, a major component obtained by thermal treatment of cashew nut shell liquid, is a phenol derivative mainly having a C15 unsaturated hydrocarbon chain with 1–3 double bonds at the m‐position. We polymerized cardanol using an Fe‐salen complex as the catalyst to give a soluble polyphenol containing the unsaturated alkyl group in the side chain. The polymer was subjected to hardening by a cobalt naphthenate catalyst or thermal treatment, yielding crosslinked film with high gloss surface.