Sieving-type Electric Double Layer with Hydrogen Bond Interlocking to Stable Zinc Metal Anode.

The stability of aqueous zinc metal batteries is significantly affected by side reactions and dendrite growth on the anode interface, which primarily originate from water and anions. Herein, we introduce a multi H-bond site additive, 2, 2'-Sulfonyldiethanol (SDE), into an aqueous electrolyte to construct a sieving-type electric double layer (EDL) by hydrogen bond interlock in order to address these issues. On the one hand, SDE replaces H2O and SO42- anions that are adsorbed on the zinc anode surface, expelling H2O/SO42- from the EDL and thereby reducing the content of H2O/SO42- at the interface. On the other hand, when Zn2+ are de-solvated at the interface during the plating, the strong hydrogen bond interaction between SDE and H2O/SO42- can trap H2O/SO42- from the EDL, further decreasing their content at the interface. This effectively sieves them out of the zinc anode interface and inhibits the side reactions. Moreover, the unique characteristics of trapped SO42- anions can restrict their diffusion, thereby enhancing the transference number of Zn2+ and promoting dendrite-free deposition and growth of Zn. Consequently, utilizing an SDE/ZnSO4 electrolyte enables excellent cycling stability in Zn//Zn symmetrical cells and Zn//MnO2 full cells with lifespans exceeding 3500 h and 2500 cycles respectively.

Diagnostic value of MRI-DWI signal intensity value combined with serum PGI, PGII and CA199 in early gastric cancer.

To explore the diagnostic value of MRI-DWI signal intensity value combined with serum PGI. PGII and CA199 in early gastric cancer. Sixty cases of gastric cancer patients admitted to our hospital from December 2019 to December 2020 were selected as the gastric cancer group and 80 cases of healthy volunteers who underwent physical examination in our hospital during the same period were selected as the healthy group. All the 60 patients underwent MRI-DWI examination, and the pathological diagnosis results were regarded as the gold standard. MRI-DWI images, MRI-DWI signal intensity values of patients with different degrees of gastric cancer differentiation. Serum PGI, PGII and CA199 levels of subjects in the two groups were compared. AUC was used to evaluate the diagnostic value of MRI-DWI signal intensity value combined with serum PGI, PG II and CA199 for early gastric cancer. In the healthy group, T1W1 showed relatively uniform low signal intensity. While T2WI showed no significant increase in signal intensity. In the gastric cancer group. There was diffuse gastric wall thickening, local thickening or mass formation; T1WI and WATS showed slightly lower signal intensity in the lesion area. T2WI, FLAIR and B-TFE showed slightly uneven or moderately increased signal intensity. DWI showed limited diffusion, and the signal intensity increased uniformly or more uniformly, and the range of increase was clear. The signal intensity of MRI-DWI was 89.12 ± 8.14 in patients with low differentiation, 82.17 ± 6.35 in patients with moderate differentiation, and 74.52 ± 4.53 in patients with high differentiation. There were significant differences in the signal intensity of MRI-DWI among the three groups, and the difference was statistically significant (F=12.214, P <0.05). Serum PGI levels of subjects in the gastric cancer group were significantly lower than those in the healthy group, and the levels of PGII and CA199 were significantly higher than that in the healthy group, with statistical significance (P <0.05). The AUC, sensitivity and specificity of MRI-DWI signal intensity value and serum PGI, PGII and CA199 combined indexes in the diagnosis of gastric cancer were significantly higher than those of the independent indexes, with statistical significance (P <0.05). Conclusion: MRI-DWI signal strength value, serum PGI, PGII and CA199 levels are closely related to the occurrence and development of early gastric cancer. The combined detection and diagnosis efficiency is higher, which is helpful to improve the detection rate of early gastric cancer and is worthy of extensive clinical application.

Ecological risks assessment and pollution source identification of trace elements in contaminated sediments from the Pearl River Delta, China.

Sediments from 14 stations in the Foshan Waterway, a river crossing the industrial district of Guangdong Province, South China, were sampled and subsequently analyzed. The 14 stations were selected for the pollution discharging features of the river, such as the hydrology, the distribution of pollution sources, and the locations of wastewater outlets. The ecological risks were assessed, and the pollution sources were identified to provide valuable information for environmental impact assessment and pollution control. The spatial variability was high and the range were (in milligrams per kilogram dry weight): Pb, 46.0~382.8; Cu, 33.7~ 482.3; Zn, 62.2~1,568.7; Ni, 28.5~130.7; Cr, 34.7~1,656.1; Cd, 0.50~8.53; Hg, 0.02~8.27; and As, 5.77~66.09. The evaluation results of enrichment factor and potential ecological risk index indicate that the metal pollution in the surface and bottom sediments were severely polluted and could pose serious threat to the ecosystem in most stations. Although the hazard levels of the trace element differed among the stations, Hg was the most serious pollutant in all stations. The results of principal component analysis (PCA) show that the discharge of industrial wastewater is the most important polluting factor whereas domestic sewage, which contains a large amount of organic substances, accelerates metal deposition. And potential pollution sources were identified by the way of integrating the analysis results of PCA and data gained from the local government. Therefore, the conclusion is drawn that Foshan Waterway is seriously polluted with trace elements, both in the surface sediment (0 to 20 cm) and the bottom sediments (21 to 50 cm) are contaminated.

An amperometric cholesterol biosensor based on multiwalled carbon nanotubes and organically modified sol-gel/chitosan hybrid composite film.

A new type of amperometric cholesterol biosensor based on sol-gel chitosan/silica and multiwalled carbon nanotubes (MWCNTs) organic-inorganic hybrid composite material was developed. The hybrid composite film was used to immobilize cholesterol oxidase on the surface of Prussian blue-modified glass carbon electrode. Effects of some experimental variables such as enzyme loading, concentration of Triton X-100, pH, temperature, and applied potential on the current response of the biosensor were investigated. Analytical characteristics and dynamic parameters of the biosensors with and without MWCNTs in the hybrid film were compared, and the results show that analytical performance of the biosensor can be improved greatly after introduction of the MWCNTs. Response time, sensitivity, linear range, limit of detection (S/N=3), and apparent Michaelis-Menten constant Km are 25s, 0.54 microA mM(-1), 8.0 x 10(-6) to 4.5 x 10(-4) M, 4.0 x 10(-6) M, and 0.41 mM for the biosensor without MWCNTs and 13 s, 1.55 microA mM(-1), 4.0 x 10(-6) to 7.0 x 10(-4) M, 1.0 x 10(-6) M, and 0.24 mM for the biosensor with MWCNTs, respectively. The activation energy of the enzyme-catalyzed reaction was measured to be 42.6 kJ mol(-1). This method has been used to determine the free cholesterol concentration in real human blood samples.