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A simple and sensitive fluorescence enhancement assay of trace cysteine (Cys) is presented. The method is based on the redox reaction between the Cu2+-morin complex and Cys. In Britton-Robinson buffer of pH 7.4, the addition of Cys to the Cu2+-morin system results in dramatic fluorescence intensity increase at 539 nm which is proportional to the concentration of Cys over the range of 6.52 × 10−7–2.20 × 10−5 mol L−1, with a limit of detection of 6.52 × 10−8 mol L−1. The method was applied to determine Cys in protein hydrolysate of fresh porcine blood and human urine, the recoveries being 91.3–94.1% and 95–98.6% respectively. The mechanism involved in the reaction was also studied. [ABSTRACT FROM AUTHOR]

The repeatable bipolar resistive switching phenomenon is observed in amorphous Al2O3 prepared by metal-organic chemical vapor deposition on ITO glass, with ITO as the bottom electrode and Ag as the top electrode. The crystal structure, morphology, composition and optical properties of Al2O3 thin films are investigated by x-ray diffraction, x-ray photoelectron spectroscopy, atomic force microscopy and ultraviolet-visible-infrared spectroscopy, respectively. The electronic character of Ag/Al2O3/ITO structure is tested by an Agilent B1500A. The device shows a typical bipolar resistive switching behavior under the dc voltage sweep mode at room temperature. The variation ratio between HRS and LRS is larger than nearly three orders of magnitude, which indicates the good potential of this structure in future resistive random access memory (ReRAM) applications. Based on the conductive filament model, the high electric field is considered the main reason for the resistive switching according to our measurements. [ABSTRACT FROM AUTHOR]