Biological oxidation of arsenite in synthetic groundwater using immobilised bacteria

Biological oxidation of arsenite (As(III)) in synthetic groundwater was examined by using arsenite oxidising bacteria (AOB) isolated from an activated sludge. The phylogenetic analysis indicated that the isolated AOB was closely related to Ensifer adhaerens. Batch experiments showed that for an As(III) oxidation with the isolated AOB the optimum ratio of nitrogen source (NH₄-N) concentration to As(III) concentration was 0.5 (52 mg/L-110 mg/L) and the isolated AOB preferred pH values ranging from 6 to 8, and water temperatures greater than 20 °C. Further continuous experiments were conducted using a bioreactor with immobilised AOB. With an initial As(III) concentration of 1 mg/L at a hydraulic retention time (HRT) of 1 h, an As(III) oxidation rate was around 1 × 10⁻⁹ μg/cell/min and an As(III) oxidation efficiency of 92% was achieved. Although the maximum oxidation rate measured at an HRT of 0.5 h was 2.1 × 10⁻⁹ μg/cell/min, the oxidation efficiency decreased to 87%.These results advocate that a biological process involving immobilised AOB may be useful as an economical and environmentally friendly pre-treatment step for As removal from groundwater.     

Weighted Homo-Lumo Energy Separations for the Polyene References of Fullerenes with Up to 100 Carbon Atoms

Abstract

The T value represents the HOMO-LUMO energy separation of a ?-electronic system weighted with the number of conjugated atoms. We found that this value is kept almost constant for the polyene references defined graph-theoretically for isolated-pentagon isomers of fullerenes with up to 100 carbon atoms. on this numerical basis, the T value can safely be considered as a realistic index of kinetic stability or chemical inertness for all fullerenes without abutting pentagons.     

A magnetic semiconductor protective device with built-in multifunction sensors

This paper describes protectors and multisensors using ferrite-magnetic semiconductor (FMS). Useful FMS devices with Curie temperature from ?15° to 300°C, in which the ferromagnetic properties below are retained below the Curie temperature, can be produced. The magnetic and electrical properties of FMS depend on temperature, humility, and gas concentration and can perform a switching function. The magnetic reluctance increases with temperature and approaches a maximum at the Curie temperature, but is independent of humidity or the concentration of combustible gases. The semiconducting resistance decreases from 225 to 170 kω as the humidity changes from 50 to 90 percent The FMS's specific dielectric constant above 900 is dependent on temperature, humidity, and the concentrations of combustible gases, including acetone, methanol, and ammonia In methanol, the capacitance increases from 0.18 to 0.5 nF as the concentration rises from 0 to 850 ppm. Bidirectional switching characteristics appear at voltages above 250 V. These characteristics should have practical applications in protective and measuring instruments. An overheating/overvoltage protector with temperatwe/humidity/gas concentration sensors composed of two annular FMSs is described.     

Oriented immobilization of immunoglobulin G onto the cuvette surface of the resonant mirror biosensor through layer-by-layer assembly of multilayer films

A new method for oriented immobilization of immunoglobulin G (IgG) onto the cuvette surface of the resonant mirror biosensor through layer-by-layer (LBL) assembly of multilayer films composed of avidin/gold nanoparticles (GNp)/protein A/IgG was developed. First, avidin was added in the biotin cuvette, and then injected GNp, followed by the injection of protein A for oriented immobilization of IgG. The rinsing with PBS was applied at the end of each assembly deposition for dissociating the weak adsorption. Second, IgG was added in the protein A-coated cuvette, and regenerated by incubation with 0.1 M glycine–HCL buffer. Third, different concentrations of IgG were measured by repeating the second process. Film assembling and properties of the interaction between protein A and IgG were studied by resonant mirror biosensor and electrochemical measurements. Results confirmed that IgG was successfully oriented on the protein A-coated cuvette surface by LBL assembly of multilayer films. The interaction response was dose-dependent which showed a linear range of 0.1 – 1.6 g L^− 1 IgG, with a detection limit of 8.7 mg L^− 1 estimated at a signal-to-noise ratio of 3. Moreover, the assay for oriented immobilization of IgG exhibited a good reproducibility and a favorable reusability. This method can provide a promising platform for fabricating immunoassay and immunosensor systems, protein reactors or protein-modified substrates, and affinity probes.     

Cathodoluminescence investigation of organic materials

Cathodoluminescence (CL) properties of various kinds of organic material were investigated for the purpose of staining biological specimens and obtaining CL images. Several kinds of organic light emitting device (OLED) material exhibited CL. The europium complex, Eu(dbm)3(phen), showed the strongest CL signal and was chemically modified for biological staining. However, the CL intensity from the stained biological specimen was too weak to build CL images. We discussed the CL properties of organic materials considering their chemical structure and charge distribution in the molecules.     

Revaluation of the once-through type flash distillation plant

The multi-stage flash distillation plant — especially the recirculation process—has been widely used for desalination, but the fundamental once-through process is no longer studied nowadays. The characteristics of the once-through type flash distillation plant are considered in this paper in comparison with the recirculation type. The once-through process has many superior characteristics. The method involves several problems, but almost all of them can be solved using the technology developed for the recirculalion process. The effects of boiling point elevation and of the wide scale free range caused by low salt concentration are discussed together with several other problems.     

Prediction of fiber orientation in injection molded parts of short-fiber-reinforced thermoplastics

Fiber orientation induced by injection mold filling of short-fiber-reinforced thermoplastics (FRTP) causes anisotropy in material properties and warps molded parts. Predicting fiber orientation is important for part and mold design to produce sound molded parts. A numerical scheme is presented to predict fiber orientation in three-dimensional thin-walled molded parts of FRTP. Folgar and Tucker's orientation equation is used to represent planar orientation behavior of rigid cylindrical fibers in concentrated suspensions. The equation is solved about a distribution function of fiber orientation by using a finite difference method with input of velocity data from a mold filling analysis. The mold filling is assumed to be nonisothermal Hele-Shaw flow of a non-Newtonian fluid and analyzed by using a finite element method. To define a degree of fiber orientation, an orientation parameter is calculated from the distribution function against a typical orientation angle. Computed orientation parameters were compared with measured thermal expansion coefficients for molded square plates of glass-fiber-reinforced polypropylene. A good correlation was found.     

Overexpression of Aspergillus aculeatus cellobiohydrolase I in Aspergillus oryzae

To express the cbhI gene, encoding Aspergillus aculeatus cellobiohydrolase I (CBHI), in Aspergillus oryzae, a plasmid was constructed. The strain that displayed the strongest CBHI activity among the transformants produced about 941 mg/l in liquid culture. It was confirmed by a PCR method that the plasmid was integrated at the niaD locus.     

A modified ninhydrin reagent using ascorbic acid instead of potassium cyanide

The use of a modified ninhydrin reagent using ascorbic acid instead of potassium cyanide was investigated for the photometric determination of amino acids. It has been found possible to obtain an almost stoichiometric reaction for glutamic acid with a quantitative yield of "Ruhemann's purple", the end-product of the reaction, using ascorbic acid as a safe and economical reducing agent. The modified ninhydrin reagent was composed of 0.5 g of ninhydrin, and 15 mg of ascorbic acid in 60 ml of methyl cellosolve.     

Manufacturing Method of Stable Enteric Granules of a New Antiulcer Drug (Lansoprazole)

In our previous studies, we clarified that enteric granules are an appropriate dosage form for lansoprazole, and we demonstrated that enteric granules could be produced when magnesium carbonate was added as an alkaline stabilizer.

These granules however were found to be some unstable under severe conditions because some of the excipients are incompatible with lansoprazole. We therefore attempted granulation not using these incompatible excipients and could obtain more stable enteric granules using a centrifugal fluid-bed granulator instead of an extruder-spheronizer. We also compared the absorption and dissolution properties of the enteric granules manufactured by these two methods.