A novel amplification strategy based on DNAzyme functionalized gold nanoparticles was employed to enhance the sensitivity of an electrochemical sensor for detection of Pb2+. The detection limit is 0.028 nM, which is much lower than for other electrochemical DNAzyme sensors.

Over the past forty years intensive investigations into the use of compliant surfaces have been undertaken, both theoretically and experimentally, in order to obtain turbulent drag reduction in boundary-layer flows. Although positive results were found in some of the studies, none of these had been successfully validated by independent researchers. In this paper the results are reported of a recent investigation carried out by the authors to verify the experimental results of Semenov and Kulik et al. in 1991, who successfully demonstrated the ability of compliant surfaces to reduce the skin-friction drag and surface-flow noise in a turbulent boundary layer. A straingauge force balance was used in the present study to directly measure the turbulent skin-friction drag of a slender body of revolution in a water tunnel. Changes in the structure of turbulent boundary layer over a compliant surface in comparison with that over a rigid surface were also examined. The results clearly demonstrate that the turbulent skin friction is reduced for one of the two compliant coatings tested, indicating a drag reduction of up to 7% within the entire speed range of the tests. The intensities of skin-friction and wall-pressure fluctuations measured immediately downstream from the compliant coating show reductions in the intensities of up to 7 and 19%, respectively. The results also indicate reductions in turbulence intensity by up to 5% across almost the entire boundary layer. Furthermore, an upwards shift of the logarithmic velocity profile is also evident indicating that the thickness of the viscous sublayer is increased as a result of turbulent drag reduction due to the compliant coating. It is considered that the results of the present experimental investigation convincingly demonstrate for the first time since the earlier work in Russia (Semenov and Kulik et al.) that a compliant surface can indeed produce turbulent drag reduction in boundary-layer flows.

Electronic textiles may revolutionize many fields, such as communication, health care and artificial intelligence. To date, unfortunately, computing with them is not yet possible. Memristors are compatible with the interwoven structure and manufacturing process in textiles because of its two‐terminal crossbar configuration. However, it remains a challenge to realize textile memristors owing to the difficulties in designing advanced memristive materials and achieving high‐quality active layers on fiber electrodes. Herein we report a robust textile memristor based on an electrophoretic‐deposited active layer of deoxyribonucleic acid (DNA) on fiber electrodes. The unique architecture and orientation of DNA molecules with the incorporation of Ag nanoparticles offer the best‐in‐class performances, e.g., both ultra‐low operation voltage of 0.3 V and power consumption of 100 pW and high switching speed of 20 ns. Fundamental logic calculations such as implication and NAND are demonstrated as functions of textile chips, and it has been thus integrated with power‐supplying and light emitting modules to demonstrate an all‐fabric information processing system.

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Summary Two kinds of green tea were prepared with the young shoots of Camellia kucha and C. ptilophylla, and antioxidative activities of the chemical constituents were determined. Levels of alkaloids, catechins, total polyphenols, flavonoids and amino acids were determined by high‐performance liquid chromatography and UV‐Vis spectrophotometer. Antioxidative activity was evaluated by applying 2,2‐diphenyl‐1‐picrylhydrazyl radical assay and ferric reducing antioxidant power assay. Our results showed that theobromine was the only alkaloid in C. ptilophylla, while there was theacrine in C. kucha, which was coexisting with the caffeine. We confirmed the high content of (−)‐gallocatechin gallate in C. ptilophylla was not the epimerisation of (−)‐epigallocatechin gallate during the heating procedure. These wild teas had higher content of tea polyphenols, water extracts, amion acids and stronger antioxidative activity compared with the longjing tea. They could be used for the development of noncaffeine beverages and new types of tea.

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