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The measurement of illicit drugs in wastewater is increasingly being adopted as a method for objective monitoring of population-level illicit drug use. This work describes the first small-volume direct-injection ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous determination of 11 illicit drugs and metabolites in wastewater. The method required an injection volume of only 30 µL of wastewater sample, the limits of detection (LOD) ranged from 0.4 ng/L to 2 ng/L and the lower limits of quantitation (LLOQ) ranged from 1 ng/L to 5 ng/L. Application of the method to real wastewater samples collected from wastewater treatment plants revealed morphine in all samples, together with other illicit drugs (methamphetamine, codeine, ketamine, and nor-ketamine) in some samples. Small-volume direct injection showed great potential as an efficient method for the high-throughput determination of illicit drugs in wastewater., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

MicroRNAs (miRNAs) are regarded as important biomarkers for disease diagnostics and therapeutics due to their significant regulatory roles in physiologic and pathologic processes. Herein, a versatile nanoprobe based on reduced graphene oxide (rGO) and nucleic acid (DNA) probe was prepared for simultaneously visualize miR-451a and miR-214-3p in living cells. In vitro experiments demonstrated that the nanoprobe exhibits excellent selectivity and outstanding sensitivity as low as 1 nM towards miR-451a and miR-214-3p. Moreover, the detection signals of miRNAs have good linearity in their respective concentration ranges (miR-451a: 1-100 nM, Y 1  = 9.3062X 1 +114.85 (R 2  = 0.9965). miR-214-3p: 1-200 nM, Y 2  = 1.4424X 2 +91.312 (R 2  = 0.9961)). Finally, simultaneous dual-color imaging of miR-451a and miR-214-3p in human breast cancer cells (MDA-MB-231) was realized by exploiting the P 1 &P 2 @rGO nanoprobe. In summary, this simple and effective strategy provides a general sensing platform for highly sensitive detection and simultaneous imaging of dual miRNAs in living cells., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A label-free, ultra-sensitive and turn-on method for detecting RNase A has been developed using enhanced DNA-templated silver nanoclusters (DNA-AgNCs) as the fluorescence probe. In this system, an RNA strand, which can perfectly hybridize with DNA template of nanocluster synthesis, was applied to lock the fluorescent signal of DNA-AgNCs by forming an RNA/DNA duplex. Meanwhile, the hybridized RNA/DNA duplex was used as the substrate of RNase A. The fluorescence signal of AgNCs was restored due to the degradation of RNA by RNase A. From the fluorescence signal change of this system caused by RNase A, it was found that the fluorescence signal showed a positive linear relation with RNase A concentration in the range from 0.2 pg/μL to 10 pg/μL with a detection limit of 0.098 pg/μL. Except for potential inhibitor screening and the kinetic study of this enzyme, this strategy was further used for monitoring dynamic change of RNase A in living cells successfully. In summary, the simple and sensitive method for RNase A assay can be hopefully used for drug screening in vitro and in vivo., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Hair samples from 190 relatively healthy 20- to 98-year-old volunteers from a mountain village of Tonglu city (Zhejiang province, China) were analyzed to determine the contents of 33 chemical elements (Ag, Al, As, Au, B, Ba, Be, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, Hg, Li, Mg, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sr, Th, Ti, Tl, U, V, Zn, and Zr) with the aim of assessing preliminary reference values. Mean values, median values, ranges and selected percentiles of all element concentrations in scalp hair are presented. By comparing data from different countries, it was determined that the mean concentrations of the majority of elements in our study clearly differed from the mean levels reported in the literature. The effects of gender and age on element concentrations were also investigated. Significant differences that were correlated with age and gender were determined for certain elements. For example, Fe exhibited a mean value of 11.26mg/kg for males and 4.37mg/kg for females. An age-dependent pattern for Fe was also apparent when the two age subgroups of 20-59 and 60-98 years were compared., (Copyright © 2014 Elsevier Inc. All rights reserved.)