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The catalysts for low‐temperature selective catalytic reduction of NO with NH3 (NH3‐SCR) are highly desired due to the large demand in industrial furnaces. The characteristic of low‐temperature requires the catalyst with rich active sites especially the redox sites. Herein, the authors obtain oxygen defect‐rich β‐MnO2 from a crystal phase transformation process during air calcination, by which the as‐prepared γ‐MnO2 nanosheet and nanorod can be conformally transformed into the corresponding β‐MnO2. Simultaneously, this transformation accompanies oxygen defects modulation resulted from lattice rearrangement. The most active β‐MnO2 nanosheet with plentiful oxygen defects shows a high efficiency of > 90% NO conversion in an extremely wide operation window of ≈120–350 °C. The detailed characterizations and density functional theory (DFT) calculations reveal that the introduction of oxygen defects enhances the adsorption properties for reactants and decreases the energy barriers of *NH2 formation more than 0.3 eV (≈0.32–0.37 eV), which contributes to a high efficiency of low‐temperature SCR activity. The authors finding provides a feasible approach to achieve the oxygen defect engineering and gains insight into manganese‐based catalysts for low‐temperature NO removal or pre‐oxidation.

Bacterial infection of the wounds delays the healing process, increases the risk of becoming chronic trauma associated with pain and complications, and offers a breeding ground for drug-resistant bacteria. A...

The Cr-doped CeO2–TiO2 catalysts (CrCeTi) were produced via a coprecipitation method and used for selective catalytic reduction (SCR). The CrCeTi catalyst has good catalytic performance and sulfur resistance. The results of X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), NH3-TPD, NO-TPD, X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (H2-TPR) suggested that the CrCeTi catalyst with high specific surface area (SSA), strong surface acidity, enhanced redox properties, and effective electron transfer (3Ce4+ + Cr3+ ↔ 3Ce3+ + Cr6+) were the important promotion factors for excellent SCR properties. The in situ diffuse reflectance infrared spectroscopy (DRIFTS) indicated that the incorporation of Cr could improve the adsorption capacity of nitrate and the activation capacity of NH3, which were conducive to enhancing the catalytic activity. The thermogravimetric analysis-mass spectrometry (TG-MS) confirmed that the doping of Cr reduced SO2 surface adsorption and promoted the decomposition of NH4HSO4 (ABS). Therefore, the CrCeTi catalyst showed excellent resistance to SO2 poisoning.

Purpose Developing a sensitive SERS-based method to quantitatively detect serum biomarkers (Aβ1-42 and P-Tau-181) for the early diagnosis of Alzheimer’s disease (AD). Methods In this study, a novel SERS-based sandwich immunoassay, which consists of tannin-capped silver nanoparticles and magnetic graphene oxide (Fe 3 O 4 @GOs), was developed. We firstly applied this method for the detection of protein standards in buffer solution, obtaining the regression equation. Then, its potential value on real serum samples of AD was further explored. Results The detection linear range of Aβ1-42 and P-Tau-181 protein standards were observed to range from 100 pg mL −1 to 10 fg mL −1 , 100 pg mL −1 to 1 fg mL −1 respectively. We finally explored clinical application of the proposed method in 63 serum samples. As a result, P-tau-181 differentiated AD from non-AD dementia patients (AUC = 0.770), with a more favored ROC than Aβ1-42 (AUC = 0.383). Conclusion The developed SERS-based immunoassay is successfully applied to the determination of Aβ1-42 and P-Tau-181 in human serum specimens, which provides a promising tool for the early diagnosis of AD.

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The antioxidant capacity (AC) and antioxidant activity (AA) of three flavonols (FLV), aglycones and their glycosylated derivatives were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays in various solvents. Findings confirmed that the glycosylation at the 3-position (3-glycosylation) always decreased the AC under most conditions due to substitution of the 3-position hydroxyl group and glycoside disruption in the molecular planarity. The 7-glycosylated derivatives did not have the above effects, thus generally exhibited ACs similar to their aglycones. Glycosylation decreased the AA of kaempferol and isorhamnetin for both assays in methanol, 3-glycosylation inhibited quercetin AA in the ABTS assay. In the DPPH assay, the AA of 3-glycosylated quercetin was significantly higher than quercetin. Using LC–MS/MS analysis, we found that quercetin and quercetin-7-glucoside underwent dimerization during the antioxidant reaction, potentially leading to a decline in AAs. However, 3-glycoside substitution may have hindered dimer formation, thereby allowing the FLVs to retain strong free radical scavenging abilities.