A novel strategy to fabricate an aptasensor for potassium with high sensitivity and selectivity by using nicking endonuclease is proposed in this work. A nicking endonuclease (Nt.CviPII), which may recognize specific nucleotide sequences in double-stranded DNA formed by a potassium-binding aptamer and a linker DNA but cleave only the linker strand, may transfer and amplify the quantitative information of the potassium detection to that of the linker DNA through elaborate strand-scission cycles. Since the technique for gene assay is much more mature, the linker DNA can thereby be detected by a number of available methods. Here, taking advantage of a simple and fast gold nanoparticles-based sensing technique, we are able to assay the linker and consequently potassium ion simply by UV-vis spectroanalysis and even with the naked eye. Results show that a 2 μL sample containing 0.1 mM of potassium is enough to induce distinct color appearance of the nanoparticles, and the potassium ion can be easily distinguished from many other ions. The strategy proposed in this work shows some unique advantages over some traditional methods and may be further developed for the detection of some other chemicals in the future.

The solubilities of glutaric acid in binary cyclohexane + cyclohexanol solvent mixtures at 298.05− 343.65 K, in binary cyclohexane + cyclohexanone solvent mixtures at 299.10−340.65 K, in binary cyclohexanone + cyclohexanol solvent mixtures at 299.75−343.65 K, and in ternary cyclohexanol + cyclohexanone + cyclohexane solvent mixtures at 298.15−330.95 K were studied by the dynamic method. The results show that the solubility of glutaric acid increases as temperature increases at constant solvent composition in three determined binary solvent systems. For binary cyclohexane + cyclohexanol and cyclohexane + cyclohexanone solvent mixtures, solubilities of glutaric acid decrease monotonically with the increasing mass fraction of cyclohexane in solvent mixtures at constant temperature. However, for binary cyclohexanone + cyclohexanol solvent mixtures, cyclohexanone with a mass fraction at 0.6 in solvent mixtures has the best dissolving capacity for glutaric acid at constant temperature. The experimental solubility data of three determined binary solvent systems were correlated by the Apelblat equation and nonrandom two-liquid (NRTL) activity coefficient model, and the correlated solubilities data were in good accord with the experimental data. The obtained binary interaction parameters for the NRTL model were used to calculate the solubilities of glutaric acid in the ternary cyclohexanol + cyclohexanone + cyclohexane solvent mixtures, which were compared with the experimental solubilities data.

Emerging evidence indicates the beneficial effects of physical exercise on human health, which depends on the intensity, training time, exercise type, environmental factors, and the personal health status. Conventional biomarkers provide limited insight into the exercise-induced adaptive processes. Circulating microRNAs (miRNAs, miRs) are dynamically regulated in response to acute exhaustive exercise and sustained rowing, running and cycling exercises. However, circulating miRNAs in response to long-term basketball exercise remains unknown. Here, we enrolled 10 basketball athletes who will attend a basketball season for 3 months. Specifically, circulating miRNAs which were involved in angiogenesis, inflammation and enriched in muscle and/or cardiac tissues were analyzed at baseline, immediately following acute exhaustive exercise and after 3-month basketball matches in competitive male basketball athletes. Circulating miR-208b was decreased and miR-221 was increased after 3-month basketball exercise, while circulating miR-221, miR-21, miR-146a, and miR-210 were reduced at post-acute exercise. The change of miR-146a (baseline vs. post-acute exercise) showed linear correlations with baseline levels of cardiac marker CKMB and the changes of inflammation marker Hs-CRP (baseline vs. post-acute exercise). Besides, linear correlation was observed between miR-208b changes (baseline vs. after long-term exercise) and AT VO2 (baseline). The changes of miR-221 (baseline vs. after long-term exercise) were significantly correlated with AT VO2, peak work load and CK (after 3-month basketball matches). Although further studies are needed, present findings set the stage for defining circulating miRNAs as biomarkers and suggesting their physiological roles in long-term exercise training induced cardiovascular adaptation.

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