4,573 research outputs found

    Design of a Flow-Through Voltammetric Sensor Based on an Antimony-Modified Silver Electrode for Determining Lithol Rubine B in Cosmetics

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    Lithol Rubine B (LRB; the disodium salt of 3-hydroxy-4-[(4-methyl-2-sulfophenyl) azo]-2-naphthalenecarboxylic acid) was detected using high-performance liquid chromatography with an electrochemical (antimony film on silver) detector (HPLC-ECD). For direct current (DC) mode, with the current at a constant potential, and measurements with suitable experimental parameters, a linear concentration from 0.125 to 1.80 μg/mL was found. The detection limit of our method was approximately 2.0 ng/mL. An antimony-modified silver detector was used to demonstrate that LRB is electrochemically reduced in acidic media and to analyze commercial cosmetics to determine their LRB content. Findings using HPLC-ECD and HPLC with an ultraviolet detector were comparable

    Improving the emission efficiency of MBE-grown GaN/AlN QDs by strain control

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    The quantum-confined stark effect induced by polarization has significant effects on the optical properties of nitride heterostructures. In order to improve the emission efficiency of GaN/AlN quantum dots [QDs], a novel epitaxial structure is proposed: a partially relaxed GaN layer followed by an AlN spacer layer is inserted before the growth of GaN QDs. GaN/AlN QD samples with the proposed structure are grown by molecular beam epitaxy. The results show that by choosing a proper AlN spacer thickness to control the strain in GaN QDs, the internal quantum efficiencies have been improved from 30.7% to 66.5% and from 5.8% to 13.5% for QDs emitting violet and green lights, respectively

    High MB solution degradation efficiency of FeSiBZr amorphous ribbon with surface tunnels

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    © 2020 by the authors. The as spun amorphous (Fe78Si9B13)99.5Zr0.5 (Zr0.5) and (Fe78Si9B13)99Zr1 (Zr1) ribbons having a Fenton-like reaction are proved to bear a good degradation performance in organic dye wastewater treatment for the first time by evaluating their degradation efficiency in methylene blue (MB) solution. Compared to the widely studied (Fe78Si9B13)100Zr0 (Zr0) amorphous ribbon for degradation, with increasing cZr (Zr atomic content), the as-spun Zr0, Zr0.5 and Zr1 amorphous ribbons have gradually increased degradation rate of MB solution. According to δc (characteristic distance) of as-spun Zr0, Zr0.5 and Zr1 ribbons, the free volume in Zr1 ribbon is higher Zr0 and Zr0.5 ribbons. In the reaction process, the Zr1 ribbon surface formed the 3D nano-porous structure with specific surface area higher than the cotton floc structure formed by Zr0 ribbon and coarse porous structure formed by Zr0.5 ribbon. The Zr1 ribbon\u27s high free volume and high specific surface area make its degradation rate of MB solution higher than that of Zr0 and Zr0.5 ribbons. This work not only provides a new method to remedying the organic dyes wastewater with high efficiency and low-cost, but also improves an application prospect of Fe-based glassy alloys

    <em>Escherichia coli</em>: A Versatile Platform for Recombinant Protein Expression

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    Among the living organisms, Escherichia coli has been the most common choice employed for recombinant protein expression. In addition to its well-characterized genetics, E. coli is fast growing, relatively cheap, and easy to handle. These fine properties, in conjunction with the success achieved in transforming plasmid DNA into E. coli, as well as the advent of various genetic engineering techniques in the 1970s, have enabled E. coli to be considered as the most favorable host for genetic manipulations. The recent advances in better comprehension of regulatory controls of gene expression and the availability of various novel approaches, which include both intracellular, e.g., through intein-mediated expression and self-cleavages, and extracellular, e.g., through the use of secretion signals, to achieve successful expression of the target proteins in E. coli further support the view that E. coli is the most promising host choice for heterologous protein expression

    Rate-1 Key-Dependent Message Security via Reusable Homomorphic Extractor against Correlated-Source Attacks

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    In this work, we first present general methods to construct information rate-1 PKE that is \KDM^{(n)}-secure with respect to \emph{block-affine} functions for any unbounded polynomial nn. To achieve this, we propose a new notion of extractor that satisfies \emph{reusability}, \emph{homomorphic}, and \emph{security against correlated-source attacks}, and show how to use this extractor to improve the information rate of the \KDM-secure PKE of Brakerski et al.~(Eurocrypt 18). Then, we show how to amplify \KDM~security from block-affine function class into general bounded size circuits via a variant of the technique of Applebaum (Eurocrypt 11), achieving better efficiency. Furthermore, we show how to generalize these approaches to the IBE setting. Additionally, our PKE and IBE schemes are also leakage resilient, with leakage rates 1o(1)1-o(1) against a slightly smaller yet still general class -- block leakage functions. We can instantiate the required building blocks from \LWE or \DDH
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