Multiple label-free detection of antigen-antibody reaction using localized surface plasmon resonance-based core-shell structured nanoparticle layer nanochip

In this research, a localized surface plasmon resonance (LSPR)-based bioanalysis method for developing multiarray optical nanochip suitable for screening bimolecular interactions is described. LSPR-based label-free monitoring enables to solve the problems of conventional methods that require large sample volumes and time-consuming labeling procedures. We developed a multiarray LSPR-based nanochip for the label-free detection of proteins. The multiarray format was constructed by a core-shell-structured nanoparticle layer, which provided 300 nanospots on the sensing surface. Antibodies were immobilized onto the nanospots using their interaction with Protein A. The concentrations of antigens were determined from the peak absorption intensity of the LSPR spectra. We demonstrated the capability of the array measurement using immunoglobulins (IgA, IgD, IgG, IgM), C-reactive protein, and fibrinogen. The detection limit of our label-free method was 100 pg/mL. Our nanochip is readily transferable to monitor the interactions of other biomolecules, such as whole cells or receptors, with a massively parallel detection capability in a highly miniaturized package. We anticipate that the direct label-free optical immunoassay of proteins reported here will revolutionize clinical diagnosis and accelerate the development of hand-held and user-friendly point-of-care devices.     

Determination of glycarbylamide residues in chicken tissues by HPLC with post-column reaction

A newly developed HPLC method for determination of glycarbylamide (GB) in chicken liver was applied to other tissues (muscle, fat and kidney). The recoveries of GB in muscle, fat and kidney were 87.2% (CV 0.5), 91.3% (CV 4.7), 79.7% (CV 1.0), respectively. The detection limit of GB was 0.01 ppm. GB concentrations were determined by this method in tissues (muscle, fat, liver and kidney) from chickens sacrificed 5 days after oral administration of GB mixed in feed at 60 mg/kg of feed for 7 days. GB was not detected in these chicken tissues.     

Simultaneous monitoring of protein adsorption kinetics using a quartz crystal microbalance and field-effect transistor integrated device

We developed an integrated device comprising a quartz crystal microbalance (QCM) and a field-effect transistor (FET) with a single common gold electrode in a flow chamber. An alternating current inducing oscillations in the piezoelectric quartz of the QCM sensor is electrically independent of the circuit for the FET output so that the two sensors in different detection mechanisms simultaneously record binding kinetics from a single protein solution on the same electrode. A conjunction of adsorbed mass from QCM with electric nature of bound protein from FET provided deeper understanding on a complex process of nonspecific protein adsorption and subsequent conformational changes at a solid/liquid interface. Lower apparent k(on) values obtained by FET than those obtained by QCM on hydrophobic surfaces are interpreted as preferred binding of protein molecules facing uncharged domains to the electrode surface, whereas higher k(off) values by FET than those by QCM imply active macromolecular rearrangements on the surfaces mainly driven by hydrophobic association in an aqueous medium. The advanced features of the combined sensor including in situ, label-free, and real-time monitoring provide information on structural dynamics, beyond measurements of affinities and kinetics in biological binding reactions.     

Proper decision for maintenance intervals of equipment in thermal power station based on operational rate and maintenance replacement rate

In this paper, a rational method has been proposed to determine the maintenance schedule of turbines in thermal power stations. Due to the fact that many failure data do not exist, we focused on the maintenance replacement rate, and the dimensional reduction method was used. The proper maintenance interval based on the future operational rate was chosen by the relationship between the operational rate and the maintenance interval. The results of analysis have shown a reduction in the maintenance cost, while maintaining the current reliability. The proposed method was implemented by Kyushu Electric Power Co. beginning in April 2002 to determine the maintenance schedule of turbines in thermal power stations. Moreover, it can be applied to any other system. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(1): 10–19, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10194     

Acetaldehyde tolerance in Saccharomyces cerevisiae involves the pentose phosphate pathway and oleic acid biosynthesis

To identify genes responsible for acetaldehyde tolerance, genome‐wide screening was performed using a collection of haploid Saccharomyces cerevisiae strains deleted in single genes. The screen identified 49 genes whose deletion conferred acetaldehyde sensitivity, and these were termed the genes required for acetaldehyde tolerance. We focused on six of these genes required for acetaldehyde tolerance, ZWF1, GND1, RPE1, TKL1 and TAL1, which encode enzymes in the pentose phosphate pathway (PPP), and OAR1, which encodes for NADPH‐dependent 3‐oxoacyl‐(acyl‐carrier‐protein) reductase. These genes were not only responsible for acetaldehyde tolerance but also turned out to be induced by acetaldehyde. Moreover, the content of oleic acid was remarkably increased in yeast cells under acetaldehyde stress, and supplementation of oleic acid into the media partially alleviated acetaldehyde stress‐induced growth inhibition of strains disrupted in the genes required for acetaldehyde tolerance and OLE1. Taken together, our data suggest that the supply of NADPH and the process of fatty acid biosynthesis are the key factors in acetaldehyde tolerance in the yeast, and that oleic acid plays an important role in acetaldehyde tolerance. Copyright © 2008 John Wiley & Sons, Ltd.     

Biodegradable poly(l-lactide)-grafted α-cyclodextrin copolymer displaying specific dye absorption by host–guest interactions

A biodegradable graft copolymer (CD-g-PLLA) composed of α-cyclodextrin (α-CD) and poly(l-lactide) (PLLA) was synthesized by the ring-opening polymerization of L-LA using mostly trimethylsilylated α-CD (TMS-α-CD) as an initiator. TEM measurements of the CD-g-PLLA film showed a nanoscale lamellar-type microphase-separated structure in the most of the film. In contrast, an irregular phase-separated structure was observed in the TMS-CD-g-PLLA film, suggesting that the hydroxyl groups in CD-g-PLLA governed the formation of the lamellar structure, likely because of their important roles in intra- and/or intermolecular hydrogen bonding. The CD-g-PLLA film was mechanically tenacious but soft, and it showed reduced PLLA crystallinity, high transparency, and accelerated hydrolytic degradation. The CD-g-PLLA film served as a host for various dye compounds based on specific host–guest interactions of the α-CDs.     

Chemical Composition of the Defensive Secretion of the Longhorned Beetle, <Emphasis Type="Italic">Chloridolum loochooanum</Emphasis>

Adults of the longhorned beetle, Chloridolum loochooanum Gressitt (Coleoptera: Cerambycidae) emit a white frothy secretion from their metasternal glands. This defensive substance contains cyclopentanoid monoterpenoids (iridodials), whose structures were elucidated by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) analyses that compared the naturally occurring structures with synthesized versions. Optically active citronellals, [(S)-, (R)-, and (S)/(R)- mixture], were used as starting materials for synthesizing the corresponding iridodials for the determination of the absolute configuration of the natural product. The retention time of (2S)-iridodial, derived from (S)-citronellal, corresponded to that of C. loochooanum iridodial by enantioselective GC analysis. Thus, we suggest that the absolute configuration of C. loochooanum iridodial is (1R,2S,5S)-iridodial.     

Improvement of electrical characteristics of local BOX MOSFETs by heavily doped structures and elucidation of the related mechanism

We proposed heavily doped silicon between insulators (HDSBI) MOSFETs to improve electrical characteristics of local BOX MOSFETs by using simple structures that combine local BOX regions with additional doped regions. HDSBI MOSFETs have heavily doped regions between local BOX regions, in which acceptors or traps are introduced. Simulated electrical characteristics demonstrated that they can suppress the SCEs and the kink effect, as well as the self-heating effect (SHE), which is suppressed by conventional local BOX MOSFETs. We elucidated how the additional doped regions in HDSBI MOSFETs suppress the SCEs and the kink effect. We concluded that HDSBI MOSFETs are suitable for applications, such as multi-purpose system-on-chip on which both short-channel logic circuits and high drive current circuits are integrated.     

Rare earth oxide alloys and stacked layers: An ab initio study

We report on electronic structure calculations employing density functional theory for rare earth sesquioxides and their alloys. Applying the local density approximation (LDA) for the exchange-correlation contribution fails e.g. to describe the insulating behavior of Gd₂O₃. Therefore, the LDA + U approach is employed. The resulting lattice parameters and atomic coordinates agree very well with experimental data. The optical band gap of a stacked LaLuO₃ (digital alloy) layer is predicted to be larger than the corresponding Gd₂O₃.