Latest ArticlesThe synergistic effect of Se with Fe can enhance the catalytic activities of the system for oxidation reactions. Based on this principle, a series of Se/Fe materials have been invented to develop the heterogeneous catalysts with industrial application potential. However, the present methods suffer from the tedious procedures, the high reaction temperature, and the low synthetic efficiency. In this paper, we report the synthesis of Se/Fe materials just by precipitating Fe(NO3)3 with the in situ prepared aqueous NaSe/NaSeO3 under mild conditions. The concise method may resolve the issues hindering the large-scale applications of Se/Fe materials.
The dynamic kinetic resolution (DKR) process remains a highly efficacious approach for constructing chiral amino alcohols via the catalytic asymmetric hydrogenation of α-amino ketones. We report herein a highly efficient and enantioselective anti-selective dynamic kinetic asymmetric hydrogenation of α-amino ketones catalyzed by Ir-(S)-f-phamidol system, providing various chiral amino alcohols and chiral oxazolidin-2-ones divergently with high diastereo- and enantioselectivity (up to 99% yield, up to 99% ee and up to 99:1 dr). In addition, the reaction could be performed on the gram-scale, and the resulting chiral amino alcohols are key intermediates of norephedrine and metaraminol.
Although lots of efforts have been devoted on new less hygroscopic dopants to address problems in hole transport materials (HTM), the long-time post-oxidation and the volatilization of 4-tert-butylpyridine (tBP) are still issues. A new doping mechanism for spiro-OMeTAD by disulfiram (TETD) is revealed in this work. Owing to its disulfide bond, TETD can be activated easily to produce reactive sulfur for the rapid oxidation of spiro-OMeTAD in the absence of oxygen with formation of [spiro-OMeTAD•]+[SC(S)N(C2H5)2]-. Thus, in this situation, the Li+ ion has the opportunity to coordinate tBP and fix each other in HTM film. DFT calculations suggest that the resulting favorable energy (with a ΔE of −1.29 eV) must come from the mutual interactions among Li+, TFSI−, and tBP, which is different from the well-known doping process that tBP would not participate in the doping reaction. As a result, the introduction of a new radical into the HTM greatly reduce device performance fluctuations due to the environmental dependence and inhibit tBP volatilizing for enhanced long-term stability.
Butyrylcholinesterase (BChE) is a key enzyme in the metabolism of cholinergic compounds. It has been recognized as a key biomarker for many diseases, including liver diseases and Alzheimer’s disease. However, classical methods for detecting BChE activity suffer from low sensitivity, cumbersome pre-treatment, and poor stability. Chemiluminescence is a promising new method for detecting and imaging the activity of BChE. It has several advantages over traditional methods, including low background interference, high sensitivity, and the absence of external illumination. In this study, we developed a novel BChE-activatable chemiluminescent probe (CL-BChE). It exhibited a significant chemiluminescence enhancement at 525 nm upon incubation with BChE. It had a low limit of detection (6.25 × 10−3 U/mL) and was highly selective for BChE. CL-BChE was used to image BChE activity in living cells and tumor-bearing animal models. It was also successfully applied to detect pesticide residue, even under the interference of representative phytochromes and real vegetable samples. Given its high sensitivity, selectivity, and versatility, we believe that CL-BChE will be a promising tool for investigating BChE’s activity in biomedical research as well as other BChE-related scenarios.
In order to protect the environment and economize energy, a nitrogen-fixing photocatalyst, VMCeact, is investigated in this work. This catalyst is prepared from a natural mineral, vermiculite, and modified by Ce-based metal-organic framework, Ce-UiO-66. Vermiculite was treated with formic acid; thus, Ce-UiO-66 particles grew in-situ on vermiculite; then, Ce-UiO-66 particles were activated by ultraviolet irradiation. The vermiculite absorbed visible light with a narrow band gap, and transferred photogenerated electrons to the active sites on Ce-UiO-66. Moreover, the lamella structure of vermiculite protected Ce-UiO-66 during photocatalytic process. Therefore, with only 45.92 wt% of Ce-UiO-66, the nitrogen fixation performance of VMCeact was 2.29 times that of pure activated Ce-UiO-66 particles under 455 nm light irradiation (apparent quantum efficiency of 4.49%), and retained at least 96.05% performance after 7 × 24 h of photocatalytic reaction. This cost-reduced, efficient and stable photocatalyst has the opportunity to facilitate environmentally friendly ammonia production.
Wide bandgap semiconductors are typically activated under ultraviolet (UV) light irradiation for volatile organic compounds (VOCs) degradation. However, our previous study discovered that certain VOCs can interact with some wide bandgap semiconductors, formatting an intermediate bandgap between the VOCs and the conduction band of wide bandgap semiconductor, thus inducing visible light activation of the system, and photo-generated electrons are excited by visible light and transferred from the VOCs to the conduction band of semiconductor. In this work, BaTiO3, traditionally is not active under visible light irradiation, however showed degradation rates of 100% and 20% for styrene and toluene under visible light, respectively. Density functional theory (DFT) calculations indicate that the adsorption of styrene or toluene on the BaTiO3 surface reduces its bandgap from 2.93 eV to 1.36 eV and 2.26 eV, respectively. The intermediate bandgap in this system is primarily formed by the valence band of BaTiO3 and the VOCs, and indicating that photo-generated electrons directly transfer from BaTiO3 to the VOCs under visible light, inducing degradation reactions of VOCs, i.e., this work discovered a new transfer pathway of photo-electrons direct from the valence band of BaTiO3 to VOCs, while photo-electrons are from VOCs to the conductive band of wide-bandgap semiconductors in our previous work.
RNA modifications play vital regulatory roles in biological systems. Dysregulated RNA modifications themselves or their regulators are associated with various diseases, including cancers and immune related diseases. However, to the best of our knowledge, RNA modifications in peripheral white blood cells (immune cells) have not been systematically investigated before. Here we utilized hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) for the quantification of 19 chemical modifications in total RNA and 17 chemical modifications in small RNA in peripheral white blood cells from breast cancer patients and healthy controls. We found out 13 RNA modifications were up-regulated in total RNA samples of breast cancer patients. For small RNA samples, only N6-methyladenosine (m6A) was down-regulated in breast cancer patients (P < 0.0001). Receiver operating characteristic (ROC) curves analysis showed that N4-acetylcytidine (ac4C) in total RNA had an area under curve (AUC) value of 0.833, and m6A in small RNA had an AUC value of 0.994. Our results further illustrated that RNA modifications may play vital roles in immune cell biology of breast cancer, and may act as novel biomarkers for the diagnosis of breast cancer.
Iron-porphyrin metal-organic frameworks (MOFs) have emerged as a remarkable class of semiconductors with adjustable photoelectrical properties and peroxidase-mimicking activities, yet their full potential remains largely unexplored. The organic photoelectrochemical transistor (OPECT) has been proven to be a prominent platform for diverse applications. Herein, iron-porphyrin MOFs, as bifunctional photo-gating module and horseradish peroxidase-mimicking nanozyme, is explored for novel OPECT bioanalysis. Exemplified by alpha-fetoprotein (AFP)-dependent sandwich immunorecognition and therein glucose oxidase (GOx)-generated H2O2 to etch CdS quantum dots on the surface of iron-porphyrin MOFs, this OPECT bioanalysis achieved high-performance AFP detection with a low detection limit of 24 fg/mL. This work featured a bifunctional iron-porphyrin MOFs gated OPECT, which is envisioned to inspire more interest in developing the diverse MOFs-nanozymes toward novel optoelectronics and beyond.
Fuel cell electric vehicles hold great promise for a diverse range of applications in reducing greenhouse gas emissions. In power fuel cell systems, hydrogen fuel serves as an energy vector. To ensure its suitability, it is necessary for the quality of hydrogen to adhere to the standards set by ISO 14687:2019, which sets maximum limits for 14 impurities in hydrogen, aiming to prevent any degradation of fuel cell performance. Ammonia (NH3) is a prominent pollutant in fuel cells, and accurate measurements of its concentration are crucial for hydrogen fuel cell quantity. In this study, a novel detection platform was developed for determining NH3 in real hydrogen samples. The online analysis platform integrates a self-developed online dilution module with a Fourier transform infrared spectrometer (ODM-FTIR). The ODM-FTIR can be operated fully automatically with remote operation. Under the optimum conditions, this method achieved a wide linear range between (50~1000) nmol/mol. The limit of detection (LOD) was as low as 2 nmol/mol with a relative standard deviation (RSD, n = 7) of 3.6% at a content of 50 nmol/mol. To ensure that the quality of the hydrogen products meets the requirement of proton exchange membrane fuel cell vehicles (PEMFCV), the developed ODM-FTIR system was applied to monitor the NH3 content in Chengdu Hydrogen Energy Co., Ltd. for 21 days during Chengdu 2021 FISU World University Games. The proposed method retains several unique advantages, including a low detection limit, excellent repeatability, high accuracy, high speed, good stability, and calibration flexibility. It is an effective analytical method for accurately quantifying NH3 in hydrogen, especially suitable for online analysis. It also provides a new idea for the analysis of other impurity components in hydrogen.
Photocatalytic NO removal is regarded as an attractive strategy to reduce NO pollution in the air, but the lack of efficient and stable catalysts impedes its applications. Herein, we report on developing Ti3C2 supported on N-defective g-C3N5 nanosheets (CNX/TC) as an efficient photocatalyst toward NO removal. It is noteworthy that TC changed from crystal structure to amorphous structure during the photocatalytic process. Due to the existence of N vacancies and amorphous structure, the designed CNX/TC composites possess abundant unsaturated sites for adsorption and activation of O2 and NO, thus facilitating the removal of NO and inhibiting the generation of NO2. The as-prepared CNX/TC-2% shows the best activity for NO removal and inhibits toxic NO2 generation. The removal rate of NO is up to 48%, which is about 2 and 4 times higher than those of pure CNX and CN, respectively. In addition, the in situ diffused reflection Fourier transform infrared spectroscopy was used to investigate the NO transfer pathway during the photocatalytic process. This work might provide new insights into the catalytic role of N-defect and amorphous, inspiring the rational design of catalysts in the field of photocatalytic NO removal.
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