128×128 three-dimensional MEMS optical switch module with simultaneous optical path connection for optical cross-connect systems

A 128×128 three-dimensional MEMS optical switch module and a switching-control algorithm for high-speed connection and optical power stabilization are described. A prototype switch module enables the simultaneous switching of all optical paths. The insertion loss is less than 4.6 dB and is 2.3 dB on average. The switching time is less than 38 ms and is 8 ms on average. We confirmed that the maximum optical power can be obtained and optical power stabilization control is possible. The results confirm that the module is suitable for practical use in optical cross-connect systems.     

Development and evaluation of a loop-mediated isothermal amplification assay for rapid and sensitive detection of Vibrio parahaemolyticus

Loop-mediated isothermal amplification (LAMP) assays targeting the rpoD and toxR genes were developed to detect Vibrio parahaemolyticus. All 78 tested V. parahaemolyticus strains yielded positive results within 40 min, while negative results were obtained for 69 strains of other organisms even at 60 min. For V. parahaemolyticus ATCC 17802 in pure culture, the detection limits of LAMP assays targeting rpoD and toxR were 3.7 and 450 CFU per test, respectively. Due to the higher sensitivity of rpoD-LAMP, it was further evaluated for the ability to detect V. parahaemolyticus in seafood samples. V. parahaemolyticus populations spiked in short-necked clams were enumerated by the most-probable-number (MPN) method combined with the rpoD-LAMP assay and the MPN method with a culture method using agar medium. The MPN-rpoD-LAMP method had better sensitivity and was more rapid than the conventional method. These results indicate that the MPN-LAMP assay targeting the rpoD gene is a specific, sensitive, and rapid method to enumerate V. parahaemolyticus organisms.     

Determination of carbendazim, thiophanate, thiophanate-methyl and benomyl residues in agricultural products by liquid chromatography-tandem mass spectrometry

A simple and reliable liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method was developed for carbendazim (MBC), thiophanate (TE), thiophanate-methyl (TM) and benomyl (BM) in agricultural products. These compounds were extracted from agricultural products with methanol after addition of sodium L-ascorbate. BM was hydrolyzed to MBC during the extraction with methanol. TE and TM were cyclized to ethyl 2-benzimidazole carbamate (EBC) and MBC by refluxing at 120 °C for 30 min with copper acetate in 50% acetic acid. MBC and EBC were cleaned up by an n-hexane wash and extraction with ethyl acetate and determined by LC-MS/MS. The mean recoveries from 10 agricultural products were in the range of 75.8-100.0%, and the relative standard deviations of 5 experiments were in the range of 1.5-9.2% at concentrations equal to the maximum residue limits (MRLs). The calibration curves were made by using commercial MBC and EBC as reference analytical standards without refluxing. The quantification limits were 0.01 mg/kg (as MBC), which is the uniform limit in the positive list system for agricultural chemical residues in foods in Japan.     

Influence of extracellular polymeric substances on nitrogen removal in an intermittently-aerated membrane bioreactor.

Influence of EPS on fouling of intermittent aeration MBR reactor (denitrification MBR) was investigated changing intermittent aeration cycle (10 minute-cycle and 120 minute-cycle) in laboratory-scale reactors using synthetic wastewater. EPS were extracted from bacterial cells using cation resin method and molecular weight fractioning of EPS was conducted using gel chromatography. In both of the reactors, nitrogen removal rate was almost 100% after 50th day although DO concentration was not very high during the aerated phase because of accumulation of nitrifying bacteria in the reactors. In the 120 minutes-cycle reactor, trans-membrane pressure increased more rapidly than in the 10 minutes-cycle reactor. The reason might be that EPS of more than 1000 kDa, which are the main fouling substances, are produced more rapidly in the 120 minute-cycle condition. It was also found that three peaks at around 100 kDa, 500 kDa and 2000 kDa are prominent in EPS in intermittent-aeration MBR irrespective of cycle and higher molecular weight EPS are decomposed to smaller molecular weight EPS on membrane surface.     

Influence of the composition of ternary mixed solvent electrolytes on the properties of rechargeable lithium cells

A cell system consisting of an amorphous (a-)V2O5–P2O5 (95:5 in molar ratio) cathode, a lithium metal anode and an organic electrolyte by fabricating an AA-size prototype cell has been studied. The influence of the composition of ternary mixed solvent electrolytes comprising ethylene carbonate (EC), propylene carbonate (PC) and 2-methyltetrahydrofuran (2MeTHF) on the properties of AA-size Li/a-V2O5–P2O5 cells is examined. The goals are to improve the cycle life of the cell while ensuring its safety and controlling its cost. The electrolyte composition is varied by changing the solvent mixing ratio, and the lithium salt concentration, and by using different kinds of solute. The cell performance examined includes cathode utilization (cell capacity) during low temperature operation, and charge–discharge cycle life. Heating abuse tests were also carried out at 130°C on the Li/a–V2O5–P2O5 cells. The best electrolyte composition was found to be 1.15m LiAsF6–EC/PC/2MeTHF (15:70:15) from the overall results on cycle life, capacity, safety and cost.     

采用RE-TM材料的光记录-磁读出方式

以TbFeCo为主的稀土族-过渡金属（RE-TM）合金,能够很容易地获得很大的垂直磁各向异性,适于高密度磁记录。对采用该材料的介质,应用与HDD（硬盘驱动器）同样的磁读出方式进行读出。记录方式采用基于光照射的高温消磁型热磁记录方式。该记录方式应用于磁光盘（MO）的写入。根据磁记录膜的磁特性,靠单一的磁性膜不易同时采用这些记录方式和读出方式。通过磁性膜多层化的方法解决了这个难点。磁读出方式与磁光读出方式相比,读出分辨率有很大提高,具有实现远超磁光盘记录密度的前景。     

Evaluation of 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose, a new fluorescent derivative of glucose, for viability assessment of yeast Candida albicans

A new fluorescent derivative of D-glucose, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG), which had been previously developed for the analysis of glucose uptake activity by living cells, was investigated to evaluate its applicability for assaying the viability of yeast Candida albicans. Lineweaver-Burk plots showed to uptake of 2-NBDG to be competitively inhibited by D-glucose and not by L-glucose, which suggested the involvement of the glucose transporting system of C. albicans in the uptake of 2-NBDG. A good correlation was obtained between the yeast viability, determined by the plate-count method, and the 2-NBDG uptake activity of yeast cells (correlation constant: r = 0.97). This is expected to lead to the development of a new fluorescent probe for the determination of yeast cell viability.