Influences of electroosmotic flows in nanopillar chips on DNA separation: Experimental results and numerical simulations

The various potential factors affecting the performance of nanopillar chips on DNA separation were investigated from the viewpoints of both numerical calculations and actual experiments. To yield higher performance and replace the conventional DNA separation techniques such as microchip electrophoresis, the phenomenon specific to the nanopillar chips should be deeply understood. In this paper, although various factors affecting the performance of the nanopillar chips are considered, we focused on the effect of electroosmotic flow, which is particularly noticeable in quartz-made nanopillar chips. High-resolution separation of DNA was realized when an electroosmotic flow was suppressed by simply using a higher concentration of buffer, but DNA separation failed in the presence of an electroosmotic flow. It was confirmed from the numerical simulations and the direct observations that the deformation of DNA band during the injection process was induced by electroosmotic flow and consequently led to a poor resolution.     

Identification of enzyme responsible for erythritol utilization and reaction product in yeast Lipomyces starkeyi

We have identified the enzyme responsible for erythritol utilization and its reaction product in the yeast Lipomyces starkeyi CBS 1807. The enzyme, a polyol dehydrogenase requiring NAD+ as a coenzyme, was induced by erythritol in this yeast. We confirmed that the enzyme product was L-erythrulose by MS, NMR, and polarimeter analyses, meaning that we clarified the first step of erythritol utilization in yeasts for the first time. In the case of the oxidative reaction, D-threitol, (2R,3R)-2,3-butanediol, and erythritol were much better substrates than 21 other polyols tested. These three substrates are tetroses and have an R configuration at C-3, and whose third carbon results in easiest oxidation in this enzyme. The research of the substrate specificity in the reductive reaction demonstrated that L-erythrulose and dihydroxyacetone were better substrates, that D-acetoin was inactive and L-erythrose (aldose) was slightly active.     

Aqueous phase synthesized CdSe magic-sized clusters: solution composition dependence of adsorption layer structure

We report dispersion solution composition dependence of the adsorption layer structure and the physical and optical properties of aqueous phase-synthesized semiconductor nanoparticles (NPs). We synthesized cysteine (Cys)-capped CdSe NPs with well-defined core structures, dispersed them in a series of aqueous solutions with different compositions, and then investigated their adsorption layer structure and physical and optical properties. Each CdSe NP consisted of a (CdSe)33 or (CdSe)34 magic-sized cluster (d - 1.45 nm) core, a ligand-Cys shell, and an adsorption layer. The dispersion solution composition strongly affected the adsorption layer structure of the CdSe NPs. The solution with a composition close to that of the as-prepared solution stabilized the physical and optical properties of the NPs. The solution with a composition different from that of the as-prepared solution, however, resulted in large changes in their adsorption layer structure and thus their physical and optical properties. The solution composed of neutral or weakly charged Cys and Cd-Cys complexes led to the adsorption layer with low charge density and that destabilized the NPs. The solution containing only neutral or weakly charged forms of Cys, without Cd-Cys complexes, was favorable to the formation of a thick adsorption layer with low charge density and that destabilized the NPs. The amount of adsorbed Cys in the adsorption layer depended on the dispersion solution composition. However, the amount of adsorbed Cd-Cys complexes in the adsorption layer was almost constant regardless of the dispersion solution composition.     

The desire to expel unselfish members from the group.

An initial study investigating tolerance of group members who abuse a public good surprisingly showed that unselfish members (those who gave much toward the provision of the good but then used little of the good) were also targets for expulsion from the group. Two follow-up studies replicated this and ruled out explanations grounded in the target being seen as confused or unpredictable. A fourth study suggested that the target is seen by some as establishing an undesirable behavior standard and by others as a rule breaker. Individuals who formed either perception expressed a desire for the unselfish person to be removed from the group. Implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Positive patterning of ferritin and fibronectin molecules on silicon by the atomic force microscopic anodic oxidation technique

Oxide dots fabricated on silicon (111) by the Atomic Force Microscopy (AFM) anodic oxidation technique was used for the patterning of two different proteins namely, ferritin and fibronectin. Si surfaces were oxidized by the SC1 process and then modified with octadecyltrichlorosilane (OTS) for passivation. Oxide dots were fabricated by applying a bias voltage between the AFM probe and the silicon surface. Furthermore, surface functionalization of oxide dots was achieved through gamma-aminopropyltriethoxysilane (gamma-APTES) and glutaraldehye modification to establish a covalent bond between aldehydes and amino groups of protein molecules. Topographies after each modification steps were monitored by AFM. We were able to achieve positive patterning of ferritin molecules up to an average density of 6 x 10(9)/cm2 on gamma-APTES-covered dots, while 9 x 10(8)/cm2 of ferritin molecules remained on the OTS surface. In contrast to this observation, fibronectin molecules were patterned successfully only on oxide dots, and we did not observe any fibronectin molecules on the OTS surface.     

Influences of debonding rate and temperature on tack properties and peel behavior of polyacrylic block copolymer/tackifier system

The influences of debonding rate and temperature on the peel behavior of polyacrylic block copolymer/tackifier system were investigated. Poly(methyl methacrylate)-block-poly(n-butyl acrylate)-block-poly(methyl methacrylate) triblock copolymer (MAM) with hard block contents of 23 (MAM-23) and 16 wt.% (MAM-16) and a 1/1 blend with a diblock copolymer (MA) consisting of the same components (MAM-23/MA, total hard block content of 15 wt.%) were used as the base polymer. A special rosin ester was used as a tackifier at various contents in the block copolymer/tackifier system. The peeling process at the probe/adhesive interface during probe tack testing was observed using a high-speed microscope at 23 °C with debonding rate of 10 mm/s. Three different peeling mechanisms were observed. Type A, where peeling progressed linearly from the edge to the center of the probe without cavitation (MAM-23). Type B, where peeling progressed linearly from the edge to the center of the probe with cavitation (MAM-16). Type C, where cavitation occurred over the entire adhesive layer, and peeling initiation was delayed (MAM-23/MA). The peel behavior of MAM-23 changed from Type A to Type B with a decrease of the debonding rate (1 mm/s) or increase of the temperature (40 °C). In contrast, there was no change for MAM-16 and MAM-23/MA. Cavity formation in an adhesive layer restrains peeling; therefore, it is desirable for improvement of the adhesion strength. The tack properties increased with the tackifier content, and the formation of cavitation was less than that for the systems without the tackifier.     

Reliability assessment based on hazard rate model for an embedded OSS porting‐phase

Embedded Open Source Software (OSS) systems have been gaining a lot of attention in the embedded system area. The successful experience of embedded OSSs include Android, BusyBox, TRON, etc. Also, OSS market will be expanded not only to mobile phone OSS areas but also to other embedded OSS areas in the future. However, the poor handling of quality problem and customer support prohibit the progress of embedded OSS. Also, it is difficult for developers to assess the reliability and portability of embedded OSS on a single‐board computer. A method of software reliability assessment based on flexible hazard rate modeling for the embedded OSS is proposed in this paper. Also, several numerical examples are shown by using actual data. Moreover, this paper compares the proposed model with the conventional hazard rate models by using the comparison criteria of goodness‐of‐fit. Copyright © 2011 John Wiley & Sons, Ltd.     

Fabrication and evaluation of a novel cathode-supported honeycomb SOFC stack

A novel solid oxide fuel cell (SOFC) stack based on a cathode-supported honeycomb SOFC single unit, capable of generating high volumetric power density, was fabricated. Facile connection of the honeycomb single units is achieved using a metal interconnect with a gastight conductive paste. The honeycomb single unit is designed to use the outer honeycomb face and the anode layer on the honeycomb edge face as the current collection paths for the cathode and anode sides, respectively. Current is conducted between the cathode of a single unit and the anode of an adjacent single unit through the metallic interconnect. A two-unit stack exhibited an open circuit voltage of approximately 2 V and twice the power of a single unit at 600 °C under wet H₂ fuel flow. The volumetric power density of the honeycomb SOFC stack at 600 °C was calculated to be approximately 0.6 W/cm³.     

Crystal Structure of Metastable Tetragonal Zirconia up to 1473 K

The crystal structure of metastable tetragonal zirconia prepared via the alkoxide method has been investigated at temperatures up to 1473 K, to clarify the similarity between this metastable phase and the tetragonal phase at high temperature. The lattice constants, tetragonality, oxygen shift parameter, and equivalent isotropic thermal parameter of the metastable tetragonal phase are proportional to the temperature. These parameters, when extrapolated to the high-temperature range, are very similar to those of the high-temperature tetragonal phase. Present results indicate that the structure of the metastable tetragonal phase is the same as that of the high-temperature tetragonal phase.