Exploration of the reaction mechanism of the LaFeO3 oxygen carrier for chemical-looping steam methane reforming: a DFT study.

The CO conversion is expected to be controllable for chemical-looping steam methane reforming. Herein, density functional theory (DFT) calculations were employed to systematically explore the detailed reaction mechanism of CO conversion over the LaFeO3 oxygen carrier. It is found that the FeO2-terminated surface could exhibit better activity for CO adsorption than the LaO-terminated surface. In addition, the FeO2-terminated surface is much more favorable for CO oxidation than the LaO-terminated surface and the Fe-O site is the main active site. The oxygen diffusion process is easier to proceed on the LaO-terminated surface compared with the FeO2-terminated surface. Four pathways for the reaction process between the FeO2-terminated surface and CO were proposed and oxygen diffusion was determined as the rate-limiting step. For the reaction of CO with the LaO-terminated surface, one pathway was considered and CO2 desorption is the rate-limiting step. Comprehensively, the reactivity of CO conversion over the FeO2-terminated surface is superior to that over the LaO-terminated surface. We could control the CO conversion by regulating the oxygen activity of LaFeO3. This work provides guidance for the rational design of LaFeO3 oxygen carriers in the CL-SRM process.

Label-free fluorescence strategy for methyltransferase activity assay based on poly-thymine copper nanoclusters engineered by terminal deoxynucleotidyl transferase.

The assay of detecting DNA methyltransferase activity has been identified as one of the central challenges in cancer diagnostics as DNA methylation is closely related to the diagnosis and treatment of tumors. In this study, a label-free fluorescence probe based on poly-thymine copper nanoclusters engineered by terminal deoxynucleotidyl transferase is proposed for methyltransferase activity assay. Taking advantage of the efficient polymerization extension reaction catalyzed by terminal deoxynucleotidyl transferase and the copper nanoclusters with large Stokes shift instead of labeling fluorescent dyes, the strategy exhibits a broader linear scope from 1 to 300 U mL-1 with a detection limit of 0.176 U mL-1. The economical method is specificity for M.SssI and also provides a convenient and high-throughput platform for screening the DNA methylation inhibitors, which displays a great potential for the practical applications of the drug development and clinical cancer diagnosis in the future.

Fluorometric determination of the activity of the biomarker terminal deoxynucleotidyl transferase via the enhancement of the fluorescence of silver nanoclusters by in-situ grown DNA tails.

The activity of terminal deoxynucleotidyl transferase (TdTase) is a biomarker for routine diagnosis of acute leukemia. A method has been developed for the determination of TdTase activity. It is based on the use of silver nanoclusters (AgNCs) whose yellow fluorescence is enhanced by an in-situ grown DNA tail of TdTase-polymerized and guanine-rich DNA at the 3' end of a hairpin DNA. The fluorescence, best measured at excitation/emission peaks of 530/585 nm, increases linearly in the 1 to 35 mU mL-1 TdTase activity range. The detection limit is 0.8 mU mL-1. The method is cost-efficient, selective and convenient. It integrates enhancement of the fluorescence of AgNCs and target recognition into a single process. Graphical abstract Schematic presentation of a method for determination of TdTase activity. It is based on AgNCs fluorescence enhanced by in-situ grown TdTase-polymerized G-rich DNA tail. The method integrates AgNCs fluorescence enhancement and the target recognition into a single process.

Synthesis and Biological Evaluation of 3, 8-dimethyl-5-isopropylazulene Derivatives as Anti-gastric Ulcer Agent.

Recent studies showed that Guaiazulene (GA) and Sodium guaiazulene sulfonate (GAS-Na) have good anti-gastric ulcer effect. Here, two series of GA derivatives were synthesized and evaluated for their anti-gastric ulcer activity. The data obtained from in vivo testing of these compounds in a rodent ethanol-induced stomach injury model are discussed. Among the tested compounds, A1, A4, and A9 (ulcer index: 1.125 ± 1.246**, 1.714 ± 0.756*, 1.875 ± 1.126*) exhibited better anti-gastric ulcer activity than the positive control Omeprazole (2.005 ± 1.011*). The information got from these studies and the results of 3D-SAR investigation may be useful in the design of novel anti-gastric ulcer agents.

[Simultaneous spectrophotometric determination of mixed colorants by artificial neural network].

The back propagation artificial neural network was applied to process spectrophotometric data of mixed colorants. By optimizing the network structure and parameters, the predication accuracy was enhanced. The method was used for simultaneous determination of mixed colorants in synthetic samples and drinks on sale with satisfactory results. Therefore, the artificial neural network may provide a new approach to determine the mixed colorants is drinks by spectrophotometry without any preliminary chemical separation.