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There is currently no effective real-time patient dosimeter available for use in interventional radiology (IR). We conducted a feasibility study in a clinical setting to investigate the use of the new dosimeter using photoluminescence sensors during procedures. Reference dosimeters were set at almost the same position of the prototype dosimeter sensors. We found excellent correlations between the reference measurements and those of the prototype dosimeter (r 2 = 0.950). The sensor of the new dosimeter does not interfere with the IR procedure. The new dosimeter will be an effective tool for the real-time measurement of patient skin doses during IR. [ABSTRACT FROM AUTHOR]

A novel sensor system equipped with a reactor packed with beads containing immobilized β-1,3-glucanase and glucose oxidase was developed for the amperometric determination of laminarin concentration. The proposed sensor system consisted of a reactor, an oxygen electrode, a flow cell, a pump, a buffer tank, and a recorder. The measurement was performed with a flow injection system. The optimum conditions for the sensor system were as follows: transfer solution, pH 7.0; 0.1 M phosphate buffer solution; flow rate, 0.15 ml/min; and sample volume, 50 μl. The response was correlated to the laminarin concentration. The calibration curve was obtained between 50 and 0.5 mg/ml laminarin (R2=0.994). The detection limit was 50 μg/ml laminarin (the ratio of signal/noise=3). The relative standard deviations were 2.0% (n=15) and 2.5% (n=15) for 0.4 and 1.0 mg/ml laminarin solutions, respectively. One assay was completed within 5 min. Results suggest that the sensor can be used not only for the analysis of seaweed and health-enhancing foods but also for monitoring the initial pollution of the marine environment. [Copyright &y& Elsevier]

A d-alanine (d-Ala) sensor for the monitoring of a fermentation process was developed using flow injection analysis (FIA). The FIA system consisted of a d-amino acid oxidase (d-AAOx) reactor, a Pyruvate oxidase (PyOx) electrode and a contrast electrode in the flow cell, and through the oxidation of d-amino acids in the d-AAOx reactor, pyruvic acid was formed only from d-Ala. The pyruvic acid was further oxidized with PyOx via the d-AAOx reaction. The amount of oxygen consumed in the PyOx reaction was proportional to the amount of d-Ala. It was possible to continuously repeat the assay up to 60 times at pH 6.8 and a flow rate of 0.18-ml min−1. A linear relationship was obtained in the range of 0.1–1 mM d-Ala with a correlation coefficient of 0.987 and the detection limit was 0.05 mM. The relative standard deviation (R.S.D.) was 4.9% (n=5) for 0.5 mM d-Ala. The d-Ala content in some fish sauces was also determined using the proposed sensor system. The results obtained indicated a linear relationship between the amounts of d-Ala determined by the proposed sensor system and the conventional method. From the results, even if the substrate specificity of the enzyme (d-AAOx) was low, it was evident that the concentration of the original material (d-Ala) could be determined specifically when the first reaction product was changed by the second reaction (PyOx). [Copyright &y& Elsevier]

The concentrations of d- and l-alanine in bivalves are useful as indicators of environmental pollution. Amino acid oxidase with a low substrate specificity catalyzes the oxidation of various amino acids. Among the various amino acids, pyruvic acid can be generated from alanine only by the catalytic oxidative reaction of this oxidase. Therefore, in this study, the concentrations of d- and l-alanine were determined from the concentration of pyruvic acid, which was determined from the consumption of oxygen based on the oxidative reaction of pyruvate oxidase. From this point of view, there is a very strong possibility that biosensors utilizing enzymes with a low substrate specificity can be developed. The results obtained were as follows. (1) The optimum conditions for the use of pyruvic acid sensor were as follows: temperature of 25 °C, pH of 6.8, flow rate of 0.1 ml/min, thiamin diphosphate concentration of 1.5 mM, and injection volume of 50 μl. (2) d-Alanine and l-alanine optimally reacted with d- and l-amino acid oxidase at 30 °C, pH 8.2, for 30 min and at 37 °C, pH 7.8, for 90 min, respectively. (3) The linear relationships between the concentrations of d- and l-alanine and the output of the sensor were obtained at 3.56–106.8 μg of d-alanine and 5.34–71.3 μg of l-alanine. (4) The concentrations of d- and l-alanine in Meretrix iusoria, Patinopecten yessonsi, and Corbicula leana obtained by the proposed assay were in good agreement with those determined by a conventional method. [Copyright &y& Elsevier]

Abstract: A diffusive sampling device, the DSD-NH3, has been developed for measurement of ammonia in air. The DSD-NH3 comprises silica gel impregnated with phosphoric acid as the absorbent, a porous sintered polyethylene tube that acts as a diffusive membrane, and a small polypropylene syringe that is used for the elution of analytes from the absorbent. Silica gel impregnated with phosphoric acid is used as absorbent for the DSD-NH3; basic gases in ambient air, including ammonia, are trapped in the DSD-NH3 device by their reaction with phosphoric acid in the sampler to form their corresponding phosphoric acid salts. After collection, the DSD-NH3 samplers are eluted by water. Cations in the eluate, including ammonium ions, are analyzed by ion chromatography. A side-by-side comparison was made with active samplers, demonstrating good correlation (r 2 = 0.996). The sampling rate (94.5 ml min−1) was determined from comparison with an active sampling method and sampling rates. The sampling rate is also calculated from the respective molecular weights according to a rule based on Graham’s law. The theoretical sampling rate with the DSD-NH3 is 95.4 ml min−1 and agrees with the experimental value (94.5 ml min−1). Little influence of wind velocity on the sampler was observed. The relative standard deviations for ammonia concentrations were 4.7% with face velocity ranging 0–5.0 m/s. [Copyright &y& Elsevier]

Abstract: This paper aims to investigate interfacial fracture toughness between concrete and polymer-cement mortar (PCM) in an external wall tile structure under various shear to tensile stress ratio by using interface elements in a finite element method (FEM). A constitutive material model of interface elements was developed, and its corresponding values that have a relation to the interfacial fracture toughness were calibrated with three four-point bending set-ups and one high shear test. Then, the developed interface element was verified by applying to analyze the failure of tiles in the tiled column compression test. With this method, the interfacial fracture toughness of the current interface was successfully obtained for the whole range of the shear to tensile stress ratio. Finally, the result is further discussed with the other interfaces, consisting of cementitious materials. [Copyright &y& Elsevier]