Interface Engineering via Manipulating Solvation Chemistry for Liquid Lithium-Ion Batteries Operated ≥ 100 °C.

High-performance and temperature-resistant lithium-ion batteries (LIBs), which are able to operate at elevated temperatures (i.e., >60 °C) are highly demanded in various fields, especially in military or aerospace exploration. However, their applications were  impeded by the poor electrochemical performance and unsatisfying safety issues, which was induced by the severe side reactions between electrolytes and electrodes at high temperatures. Herein, with the synergetic effects of solvation chemistry and functional additive in the elaborately designed weakly solvating electrolyte, a unique robust organic/inorganic hetero-interphase, composed of gradient F, B-rich inorganic components and homogeneously distributed Si-rich organic components, was successfully constructed on both cathodes and anodes, which would effectively inhibit the constant decomposition of electrolytes and dissolution of transition metal ions. As a result, both cathodes and anodes, without compromising their low-temperature performance, operate at temperatures ≥100 ℃, with excellent capacity retentions of 96.1 % after 500 cycles and 93.5% after ≥200 cycles, respectively, at 80 ℃. Ah-level LiCoO2||graphite full cells with a cut-off voltage of 4.3 V also exhibited superior temperature-resistance with a capacity retention of 89.9% at temperature as high as 120 ℃. Moreover, the fully charged pouch cells exhibited highly enhanced safety, demonstrating their potentials in practical applications at ultrahigh temperatures.

Use of folic acid supplementation to halt and even reverse the progression of gastric precancerous conditions: a meta-analysis.

BACKGROUND: Current data indicate that supplements such as folic acid and vitamin B may be beneficial in halting and even reversing atrophic gastritis, intestinal metaplasia and intraepithelial neoplasia, generally referred to as gastric precancerous conditions(GPC). However, there is no Meta-analysis article to evaluate the prevention and treatment of folic acid in the gastric precancerous conditions. We therefore conducted a meta-analysis to confirm the efficacy of folic acid in treating GPC. METHODS: Using a systematic review method, consider randomized controlled trials (RCT), including clinical trial reports, unpublished clinical trial data, and conference papers. The search time was been set from the database's establishment to June 2, 2021. The language was not limited, using PubMed, SinoMed, Lancet, Web of Science, CNKI, Cochrane, Ovid, Science Direct, Embase, and EBSCO databases. Data were extracted using a pre-designed extraction tool and analysis was undertaken using RevMan5.2.Besides,we use Origin software to construct the Time-dose interval analysis. RESULTS: Of the 225 records identified, 13 studies involving 1252 patients (including 11 clinical controlled trials, 1 conference paper report and 1 unpublished research report) met the inclusion conditions. Folic acid dose maintained at 20-30 mg / d for 3-6 months may be beneficial to pathological changes of GPC. Moreover, in the 3 month treatment of 5 trials, the effect was more obvious when the folic acid dose was maintained at 30 mg / d. In the 7 trials, the symptom ineffective rate of GPC treated with folic acid was 32% (RR:0.32, 95% confidence interval CI:0.21-0.48), which was combined using a fixed analysis model; The effect of folic acid on gastric mucosal atrophy in 5 trials (RR: 1.61, 95%CI 1.07-2.41). The changes of folic acid on intestinal metaplasia in the 2 experiments (RR: 1.77, 95% CI: 1.32-2.37).The 2 results are combined using a fixed analytical model. However, the subgroup analysis of 9 trials revealed no significant effectiveness of symptom. CONCLUSIONS: Our research showed that folic acid supplementation brings benefits in preventing and even reversing the progression of GPC in the stomach, and provided evidence for its potential clinical use in management of GPC. REGISTRATION: The logn number of our Meta-anlysis on PROSPERO is CRD420223062.

Characterization and utilization of methyltransferase for apramycin production in Streptoalloteichus tenebrarius.

A structurally unique aminoglycoside produced in Streptoalloteichus tenebrarius, Apramycin is used in veterinary medicine or the treatment of Salmonella, Escherichia coli, and Pasteurella multocida infections. Although apramycin was discovered nearly 50 years ago, many biosynthetic steps of apramycin remain unknown. In this study, we identified a HemK family methyltransferase, AprI, to be the 7'-N-methyltransferase in apramycin biosynthetic pathway. Biochemical experiments showed that AprI converted demethyl-aprosamine to aprosamine. Through gene disruption of aprI, we identified a new aminoglycoside antibiotic demethyl-apramycin as the main product in aprI disruption strain. The demethyl-apramycin is an impurity in apramycin product. In addition to demethyl-apramycin, carbamyltobramycin is another major impurity. However, unlike demethyl-apramycin, tobramycin is biosynthesized by an independent biosynthetic pathway in S. tenebrarius. The titer and rate of apramycin were improved by overexpression of the aprI and disruption of the tobM2, which is a crucial gene for tobramycin biosynthesis. The titer of apramycin increased from 2227 ± 320 mg/L to 2331 ± 210 mg/L, while the titer of product impurity demethyl-apramycin decreased from 196 ± 36 mg/L to 51 ± 9 mg/L. Moreover, the carbamyltobramycin titer of the wild-type strain was 607 ± 111 mg/L and that of the engineering strain was null. The rate of apramycin increased from 68% to 87% and that of demethyl-apramycin decreased from 1.17% to 0.34%.

Copper nanodot-embedded nitrogen and fluorine co-doped porous carbon nanofibers as advanced electrocatalysts for rechargeable zinc-air batteries.

Porous carbon-based electrocatalysts for cathodes in zinc-air batteries (ZABs) are limited by their low catalytic activity and poor electronic conductivity, making it difficult for them to be quickly commercialized. To solve these problems of ZABs, copper nanodot-embedded N, F co-doped porous carbon nanofibers (CuNDs@NFPCNFs) are prepared to enhance the electronic conductivity and catalytic activity in this study. The CuNDs@NFPCNFs exhibit excellent oxygen reduction reaction (ORR) performance based on experimental and density functional theory (DFT) simulation results. The copper nanodots (CuNDs) and N, F co-doped carbon nanofibers (NFPCNFs) synergistically enhance the electrocatalytic activity. The CuNDs in the NFPCNFs also enhance the electronic conductivity to facilitate electron transfer during the ORR. The open porous structure of the NFPCNFs promotes the fast diffusion of dissolved oxygen and the formation of abundant gas-liquid-solid interfaces, leading to enhanced ORR activity. Finally, the CuNDs@NFPCNFs show excellent ORR performance, maintaining 92.5% of the catalytic activity after a long-term ORR test of 20000 s. The CuNDs@NFPCNFs also demonstrate super stable charge-discharge cycling for over 400 h, a high specific capacity of 771.3 mAh g-1 and an excellent power density of 204.9 mW cm-2 as a cathode electrode in ZABs. This work is expected to provide reference and guidance for research on the mechanism of action of metal nanodot-enhanced carbon materials for ORR electrocatalyst design.