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Considering that heavy-metal contamination of seawater is getting worse, building a quick, accurate and portable device for detecting trace zinc in seawater in real time would be very beneficial. In this work, a microfluidic system was developed that includes a planar disc electrode, a micro-cavity for detection, an electrochemical workstation, a computer, a container for waste liquid reprocessing, an external pipeline and other components as well as a graphene/cerium oxide/nano-cerium oxide/Nafion composite membrane was used to modify the planar disc electrode (GR/CeO2/Nafion/Au) to investigate the electrochemical behaviour of Zn(II) using cyclic voltammetry, square-wave voltammetry and orthogonal test methods. Under optimal experimental conditions, the peak reaction current of Zn(II) showed a good linear relationship with the concentration of Zn(II) in the range of 1–900 μg/L with a correlation coefficient of 0.998, and the detection limit of the method was 0.87 μg/L. In addition, the microfluidic system had good stability, reproducibility and anti-interference. The system was used for determining zinc ions in real seawater samples, and the results were very similar to those of inductively coupled plasma–emission spectrometry, demonstrating the practicality of the system for the detection of trace zinc. [ABSTRACT FROM AUTHOR]

Phenanthrene (PHE), as a structurally simple, tricyclic, polycyclic aromatic hydrocarbon (PAHs), is widely present in marine environments and organisms, with serious ecological and health impacts. It is crucial to study fast and simple high-sensitivity detection methods for phenanthrene in seawater for the environment and the human body. In this paper, a immunosensor was prepared by using a multi-wall carbon nanotube (MWCNTs)-chitosan oligosaccharide (COS) nanocomposite membrane loaded with phenanthrene antibody. The principle was based on the antibody–antigen reaction in the immune reaction, using the strong electron transfer ability of multi-walled carbon nanotubes, coupled with chitosan oligosaccharides with an excellent film formation and biocompatibility, to amplify the detection signal. The content of the phenanthrene in seawater was studied via differential pulse voltammetry (DPV) using a potassium ferricyanide system as a redox probe. The antibody concentration, pH value, and probe concentration were optimized. Under the optimal experimental conditions, the response peak current of the phenanthrene was inversely proportional to the concentration of phenanthrene, in the range from 0.5 ng·mL−1 to 80 ng·mL−1, and the detection limit was 0.30 ng·mL−1. The immune sensor was successfully applied to the detection of phenanthrene in marine water, with a recovery rate of 96.1~101.5%, and provided a stable, sensitive, and accurate method for the real-time monitoring of marine environments. [ABSTRACT FROM AUTHOR]

Excessive fat accumulation can lead to obesity, diabetes, hyperlipidemia, atherosclerosis, and other diseases. MicroRNAs are a class of microRNAs that regulate gene expression and are highly conserved in function among species. microRNAs have been shown to act as regulatory factors to inhibit fat accumulation in the body. We found that miR-370-3p was expressed at lower levels in the fat mass of mice on a high-fat diet than in mice on a normal control diet. Furthermore, our data showed that the overexpression of miR-370-3p significantly suppressed the mRNA expression levels of adipogenic markers. Thus, miR-370-3p overexpression reduced lipid accumulation. Conversely, the inhibition of miR-370-3p suppressed 3T3-L1 preadipocyte proliferation and promoted preadipocyte differentiation. In addition, Mknk1, a target gene of miR-370-3p, plays an opposing role in preadipocyte proliferation and differentiation. Moreover, consistent results from in vitro as well as in vivo experiments suggest that the inhibition of fat accumulation by miR-370-3p may result from the inhibition of saturated fatty acids that promote the accumulation of polyunsaturated fatty acids. In conclusion, these results suggest that miR-370-3p plays an important role in adipogenesis and fatty acid metabolism through the regulation of Mknk1. [ABSTRACT FROM AUTHOR]