Flow cytometric analysis of lectin-oligosaccharide interactions by using fluorescent oligosaccharide probes

Tetraphenylethylene (TPE) derivatives have strong fluorescence in aggregated state. We report here an oligosaccharide binding assay system using tetraphenylethylene derivatives bearing oligosaccharides with aggregation-induced emission (AIE) characteristics. A tetraphenylethylene derivative bearing 6'-sialyllactose (6'SL) bound to microbeads coated with SSA lectin more effectively than RCA120 lectin. Microbeads that bound to fluorescent oligosaccharide probes could be detected by flow cytometric analysis. Tetraphenylethylene derivatives bearing oligosaccharides are useful for flow cytometric analysis of lectin-oligosaccharide interactions.     

Effects of polyglycerol esters of fatty acids and ethylene‐vinyl acetate co‐polymer on crystallization behavior of biodiesel

Biodiesel fuels (BDF) have many problems in the cold due to their crystallization properties. In particular, precipitation of large crystals of high‐melting fractions in BDF at low temperatures remarkably changes cold flow property of BDF and, thereby, it increases the values of cold filter plugging point. In this study, we evaluated polyglycerol esters of fatty acids (PGE) and ethylene‐vinyl acetate co‐polymer (EVA) as chemical additives to improve the cold flow property of palm oil‐based FAME (PFME). The results of solid fat content measurement indicate that the simultaneous addition of PGE and EVA showed synergistic effects on suppression of crystallization of PFME, however such effect was not observed when EVA was used alone. DSC thermograms indicated that the PGE additives not only decreased the crystallization temperature but also kinetically suppressed the crystal growth. Polarized light microscopy showed that the simultaneous addition of PGE and EVA led to the formation of considerably small and fine‐dispersed crystals of PFME. These results indicate that combined effects of PGE and EVA caused the formation of fine‐dispersed PFME crystals, which could improve the viscous properties of palm oil‐based BDF at relatively cold temperatures.     

Molded micro- and mesoporous carbon/silica composite from rice husk and beet sugar

A molded carbon/silica composite with high micro- and mesoporosity, as well as a high bulk density, was fabricated by activating a disk-molded precursor made from carbonized rice husk (RH) and beet sugar (BS) at 875 °C in CO₂. The pore structure of the RH- and BS-based carbon/silica composite (RBC) was analysed in relation to the bulk density. An activation time of 2.0 h provided the largest BET specific surface area (1027 m²/g) and total pore volume (0.68 cm³/g) and a low bulk density (0.54 g/cm³). An RBC that was first activated for 1 h was immersed again in BS syrup and then activated in CO₂ for 1 h. This two-step activation process provided both a high bulk density (0.69 g/cm³) and a highly textured structure (BET specific surface area, 943 m²/g; total pore volume, 0.56 cm³/g). The immersion in BS syrup was useful for improving the texture without reducing the bulk density, in comparison to one-step activation for 1.0 h. The suspension of the RBCs was basic because of the residual inorganic compounds of potassium and calcium. However, the basicity of the suspension was alleviated by washing the RBCs with water.     

Improvement of carrier diffusion length in silicon nanowire arrays using atomic layer deposition

To achieve a high-efficiency silicon nanowire (SiNW) solar cell, surface passivation technique is very important because a SiNW array has a large surface area. We successfully prepared by atomic layer deposition (ALD) high-quality aluminum oxide (Al₂O₃) film for passivation on the whole surface of the SiNW arrays. The minority carrier lifetime of the Al₂O₃-depositedSiNW arrays with bulk silicon substrate was improved to 27 μs at the optimum annealing condition. To remove the effect of bulk silicon, the effective diffusion length of minority carriers in the SiNW array was estimated by simple equations and a device simulator. As a result, it was revealed that the effective diffusion length in the SiNW arrays increased from 3.25 to 13.5 μm by depositing Al₂O₃ and post-annealing at 400°C. This improvement of the diffusion length is very important for application to solar cells, and Al₂O₃ deposited by ALD is a promising passivation material for a structure with high aspect ratio such as SiNW arrays.     

Novel CO2 Absorbents Using Lithium-Containing Oxide

We have discovered a series of lithium-containing oxides that immediately react with ambient carbon dioxide (CO₂) up to 700°C. The products react and return reversibly to the oxides at a temperatures higher than about 700°C. The absorption capacity surpasses that of other CO₂ absorbents by a factor of 10. Utilizing these absorbents, the possibility of a CO₂ separation system that operates at around 500°C is proposed. It is generally believed that a CO₂ separation process operable at temperatures higher than 500°C has the special benefit of a small energy penalty. Moreover, the absorption also proceeds at ambient temperature in the atmospheric environment. This property offers the possibility of many other applications, such as air cleaners or cartridges. Therefore, we think these materials have the potential to make a valuable contribution to the realization of CO₂ emission control.     

Friction-induced ultra-fine and nanocrystalline structures on metal surfaces in dry sliding

Sliding friction tests of pin-on-disc type were carried out for carbon steel, pure iron and pure copper, and the microstructure and hardness near the sliding surfaces were investigated in detail. It was found that patchy transfer layers with ultra-fine (<200 nm) structures were produced on the disc surfaces. Nanocrystalline grains of 30–50 nm were identified for carbon steel, and submicron sized grains of 100–150 nm were observed in pure copper. The thicknesses of the ultra-fine structures were in the range of 10–50 μm, depending on the specimen material, sliding speed and applied load. The hardness near the sliding surface of pure iron was increased compared with the matrix. It was suggested that the hardening was due to the very fine structure formed by severe plastic deformation, but not due to phase transformation caused by thermal effects.     

Estimating the germicidal effect of upper-room UVGI system on exhaled air of patients based on ventilation efficiency

Upper room (UR)-ultraviolet germicidal (UVGI) systems, one of several disinfection applications of UV, target airborne infectious diseases in rooms of buildings such as healthcare facilities. Previous studies have introduced many experiments showing the germicidal effect of UR-UVGI systems. In this study, a novel numerical method of estimating the germicidal effect of UR-UVGI systems for air exhaled by ward patients was introduced. The method adopts and modifies the concept of ventilation efficiency because the germicidal effect depends upon how the air containing airborne infectious particles flows and stays within UV-radiated area. A case study based on a four-patient ward showed that UV doses were correlated with the age of the air exhaled by a source patient, as expected. Moreover, the UV doses were considerably affected by the position of the UR-UVGI system. Inactivation rates of the influenza virus estimated using the UV doses, were in the range of 48–74%, and those of Mycobacterium tuberculosis were 68–90% in the breathing area of a neighboring patient. The results indicate not directly the decreased concentration of airborne infectious particles, but the possibility of inactivation caused by the UR-UVGI system, which is useful for system optimization.     

c-axis oriented ZnO formed in a rotating magnetic field with various rotation speeds

A rotating magnetic field was used to fabricate c-axis oriented zinc oxide. The influence of rotating speed on orientation structure was also examined. The aligned axes had the largest diamagnetic susceptibility, which axis was difficult to align with a static magnetic field. In c-axis oriented ZnO, the degree of orientation (Lotgering factor) in the green compact ranged from 0.2 to 0.5 along c-axis. The Lotgering factor increased with rotating speed. For all samples with the rotating magnetic field, the degrees of orientation increased up to above 0.9 after sintering at 1573 K.     

Ventilation efficiency of void space surrounded by buildings with wind blowing over built-up urban area

This paper outlines methods for evaluating wind-induced ventilation efficiency in void spaces in built-up urban areas. The indices of ventilation efficiency express quantitatively the ability to deliver fresh upper-tier wind to the lower tiers of void spaces and dilute pollutants emitted therein. The evaluation of ventilation efficiency is based on detailed flow analysis. The scales for ventilation efficiency, (SVEs l, 2, 3, and 6) were originally derived by the authors for room air ventilation and are also useful when applied to the exchange of air in void spaces in built-up urban areas. The other scales, namely local purging flow rate (L-PRF), visitation frequency (VF), and residence time (RT), were also re-defined by the authors for room air ventilation and had been applied for urban street canyons. They are based on detailed flow analysis and can be evaluated more easily with computational fluid dynamics (CFD) than flow modeling experiments. CFD simulation example is used to illustrate the concept of the proposed method and it is not meant to indicate the level of CFD set up for urban flow calculations. The effectiveness of the proposed method will be demonstrated more in future study.     

Influence of a fiber-network microstructure of paper-structured catalyst on methanol reforming behavior

A novel microstructured catalyst that consists of Cu/ZnO catalyst powders and ceramic fibers was successfully prepared using pulp fibers as a tentative matrix by a papermaking technique. As-prepared material, called a paper-structured catalyst, possessed porous microstructure with layered ceramic fiber networks (average pore size ca. 20 μm, porosity ca. 50%). In the process of methanol autothermal reforming (ATR) to produce hydrogen, paper-structured catalysts demonstrated both high methanol conversion and low concentration of undesirable carbon monoxide as compared with catalyst powders and pellets. The catalytic performance of paper-structured catalysts depended on the use of pulp fibers, which were added in the paper-forming process and finally removed by thermal treatment before ATR performance tests. Confocal laser scanning microscopy and mercury intrusion analysis suggested that the tentative pulp fiber matrix played a significant role in regulating the fiber-network microstructure inside paper composites. Various metallic filters with different average pore sizes, used as supports for Cu/ZnO catalysts, were subjected to ATR performance tests for elucidating the pore effects. The tests indicated that the pore sizes of catalyst support had critical effects on the catalytic efficiency: the maximum hydrogen production was achieved by metallic filters with an average pore size of 20 μm. These results suggested that the paper-specific microstructures contributed to form a suitable catalytic reaction environment, possibly by promoting efficient diffusion of heat and reactants. The paper-structured catalyst with a regular pore microstructure is expected to be a promising catalytic material to provide both practical utility and high efficiency in the catalytic gas-reforming process.