Latest ArticlesA condition-controlled strategy for selectively synthesis of 2-acylbenzothiazoles and bibenzo[b][1, 4]thiazines from aryl methyl ketones and disulfanediyldianilines was realized using I2/DMSO or I2/MeCN systems, respectively. The desired products were synthesized in only 15 min with moderate to excellent yields (50%-90%) under microwave-assisted, metal-free conditions. The strategy provides a great advantage for selective synthetic applications in the efficient synthesis of benzothiazoles and bibenzothiazines heterocycle compounds.
The trade-off between the electrochemical performance and mechanical strength is still a challenge for Ti3C2Tx free-standing electrode. Herein, a facile approach was proposed to fabricate a Microfibrillated cellulose@Ti3C2Tx (MFC@Ti3C2Tx) self-assembled microgel film by means of hydrogen bonding linkage. Benefiting from the rich hydroxyl groups on the MFC, the Ti3C2Tx nanosheets coated on the MFC in a time scale of minutes (within 1 min) instead of hours. The ultralong 1D frame of MFC effectively mitigated the re-aggregation of Ti3C2Tx nanosheet. The fluffy MFC@Ti3C2Tx film structure and the constructed 1D/2D conducting Ti3C2Tx pathways in horizontal and vertical directions endowed the fast ion transport of the electrolytes and the improved accessibility to the Ti3C2Tx surface. As a result, the freestanding MFC@Ti3C2Tx microgel film delivered a high specific capacitance of 451 F/g. And the rate performance was increased to 71% from the 64% of that of pristine Ti3C2Tx film. Furthermore, the tensile strength of MFC@Ti3C2Tx film was also promoted to 46.3 MPa, 3 folds of that of the pristine Ti3C2Tx film, due to the high strength of MFC and the hydrogen bonding effect.
An efficient approach to functionalized 4, 6-disubstituted-and 4, 6, 6-trisubstituted-1, 3-oxazinan-2-ones skeleton has been developed through the reaction of semicyclic N, O-acetals 4a and 4b with 1, 1- disubstituted ethylenes 5 or 8. As a result of such a [4 + 2] cycloaddition process, 4, 6, 6-trisubstituted- 1, 3-oxazinan-2-ones 6aa, 6af-6au, 7ba, 7bf-7bw and 6, 6-spiro containing 1, 3-oxazinan-2-ones 9ad, 9ae, 10ba-10bg were obtained in 36%-96% yields and with moderate to excellent diastereoselectivities. In addition, the synthesis of (±)-norallosedamine 12 could be conveniently achieved from the cycloadduct 7bf.
Na3V2(PO4)3 is a very prospective sodium-ion batteries (SIBs) electrode material owing to its NASICON structure and high reversible capacity. Conversely, on account of its intrinsic poor electronic conductivity, Na3V2(PO4)3 electrode materials confront with some significant limitations like poor cycle and rate performance which inhibit their practical applications in the energy fields. Herein, a simple two-step method has been implemented for the successful preparation of carbon-coated Na3V2(PO4)3 materials. As synthesized sample shows a remarkable electrochemical performance of 124.1 mAh/g at 0.1 C (1 C = 117.6 mA/g), retaining 78.5 mAh/g under a high rate of 200 C and a long cycle-performance (retaining 80.7 mAh/g even after 10000 cycles at 20 C), outperforming the most advanced cathode materials as reported in literatures.
In this work, two aza-BODIPY derivatives, 3,5-diphenyl-1,7-di(p-dodecyloxyphenyl)-aza-BODIPY (CJF) and 3,5-di(p-bromophenyl-1,7-di(p-dodecyloxyphenyl)-aza-BODIPY (2Br-CJF) acted as model molecules to form the self-assembly monolayers on the solid-liquid interface. With the utilizing of scanning tunnelling microscope (STM), we demonstrated that intermolecular Br…F—BF interactions existed in 2Br-CJF self-assembly structure and played an important role in strengthening the stability of 2Br-CJF self-assembly structure. This result is supported by density functional theory (DFT) calculation.
The effects of different species and concentrations' signal molecules on aerobic activated sludge system were investigated through batch experiments. Results showed that the fastest NH4+-N oxidization rate and the most extracellular polymeric substances (EPS) secretion were obtained by adding 5 nmol/L N-hexanoyl-l-homoserine lactone (C6-HSL) into the aerobic activated sludge. Further study investigated the correlation among N-acyl-homoserine lactones-mediated quorum sensing (AHLs-mediated QS), nutrient removal performances and microbial communities with the long-term addition of 5 nmol/L C6-HSL. It was found that C6-HSL-manipulation could enhance the stability and optimize the decontamination performance of aerobic granular sludge (AGS) system. Microbial compositions considerably shifted with long-term C6-HSL-manipulation. Exogenous C6-HSL-manipulation inhibited quorum quenching-related (QQ-related) activities and enhanced QS-related activities during the stable period. The proposed C6-HSL-manipulation might be a potential technology to inhibit the growth of harmful bacteria in AGS, which could provide a theoretical foundation for the realization of more stable biological wastewater treatments.
Pillar[5]arenes, designed and prepared by Ogoshi et al. in 2008 initially, refer to fifth classical macrocyclics. Among a wide range of pillar[5]arenes, rim-differentiated pillar[5]arenes containing five identical substituents on one rim and five different identical groups on the other rims are considered the most noteworthy type of pillar[5]arenes. As compared with the perfunctionalized pillar[5]arene, the self-assembly properties of rim-differentiated pillar[5]arenes have more varieties. On the other hand, in comparison with other types of pillar[5]arenes, the rim-differentiated pillar[5]arenes exhibit a more rigid symmetrical structure. In the present review, the synthetic methods, host-guest interactions, self-assembly properties and applications of rim-differentiated pillar[5]arenes are summarized. Hopefully, this review will be conducive to researchers in macrocyclic supramolecular chemistry.
Exosomal miRNAs, as potential biomarkers in liquid biopsy for cancer early diagnosis, have aroused widespread concern. Herein, an electrochemical biosensor based on DNA "nano-bridge" was designed and applied to detect exosomal microRNA-21 (miR-21) derived from breast cancer cells. In brief, the target miR-21 can specifically open the hairpin probe 1(HP1) labeled on the gold electrode (GE) surface through strand displacement reaction. Thus the exposed loop region of HP1 can act as an initiator sequence to activate the hybridization chain reaction (HCR) between two kinetically trapped hairpin probes: HP2 immobilized on the GE surface and biotin labeled HP3 in solution. Cascade HCR leads to the formation of DNA "nano-bridge" tethered to the GE surface with a great deal of "piers". Upon addition of avidin-modified horseradish peroxidase (HRP), numerous HRP were bound to the formed "nano-bridge" through biotin-avidin interaction to arouse tremendous current signal. In theory, only a single miR-21 is able to trigger the continuous HCR between HP2 and HP3 until all of the HP2 are exhausted. Therefore the proposed biosensor achieved ultrahigh sensitivity toward miR-21 with the detection limit down to 168 amol/L, as well as little cross-hybridization even at the single-base-mismatched level. Successful attempts were also made in the detection of exosomal miR-21 obtained from the MCF-7 of breast cancer cell line. To our knowledge, this is the first attempt to built horizontal DNA nano-structure on the electrode surface for exosomal miRNAs detection. In a word, the high sensitivity, selectivity, low cost make the proposed method hold great potential application for early point-of-care (POC) diagnostics of cancer.
Bandgap engineering through single-atom site binding on semiconducting photocatalyst can boost the intrinsic activity, selectivity, carrier separation, and electron transport. Here, we report a mixed-valence Ag(0) and Ag(Ⅰ) single atoms co-decorated semiconducting chalcopyrite quantum dots (Ag/CuFeS2 QDs) photocatalyst. It demonstrates efficient photocatalytic performances for specific organic dye (rhodamine B, denoted as RhB) as well as inorganic dye (Cr(Ⅵ)) removal in water under natural sunlight irradiation. The RhB degradation and Cr(Ⅵ) removal efficiencies by Ag/CuFeS2 QDs were 3.55 and 6.75 times higher than those of the naked CuFeS2 QDs at their optimal pH conditions, respectively. Besides, in a mixture of RhB and Cr(Ⅵ) solution under neutral condition, the removal ratio has been elevated from 30.2% to 79.4% for Cr(Ⅵ), and from 95.2% to 97.3% for RhB degradation by using Ag/CuFeS2 QDs after 2 h sunlight illumination. The intrinsic mechanism for the photocatalytic performance improvement is attributed to the narrow bandgap of the single-atomic Ag(Ⅰ) anchored CuFeS2 QDs, which engineers the electronic structure as well as expands the optical light response range. Significantly, the highly active Ag(0)/CuFeS2 and Ag(Ⅰ)/CuFeS2 effectively improve the separation efficiency of the carriers, thus enhancing the photocatalytic performances. This work presents a highly efficient single atom/QDs photocatalyst, constructed through bandgap engineering via mixed-valence single noble metal atoms binding on semiconducting QDs. It paves the way for developing high-efficiency single-atom photocatalysts for complex pollutions removal in dyeing wastewater environment.
5-Methylcytosine (5mC) is the most important epigenetic modification in mammals. The active DNA demethylation could be achieved through the ten-eleven translocation (TET) protein-mediated oxidization of 5mC with the generation of 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). It has been known that 5mC, 5hmC and 5fC play critical roles in modulating gene expression. However, unlike the 5mC, 5hmC, and 5fC, the functions of 5caC are still underexplored. Investigation of the functions of 5caC relies on the accurate quantification and localization analysis of 5caC in DNA. In the current study, we developed a method by chemical conversion in conjugation with ligation-based real-time quantitative PCR (qPCR) for the site-specific quantification of 5caC in DNA. This method depends on the selective conversion of 5caC to form dihydrouracil (DHU) by pyridine borane treatment. DHU behaves like thymine and pairs with adenine (DHU-A). Thus, the chemical conversion by pyridine borane leads to the transformation of base paring from 5caC-G to DHU-A, which is utilized to achieve the site-specific detection and quantification of 5caC in DNA. As a proof-of-concept, the developed method was successfully applied in the site-specific quantification of 5caC in synthesized DNA spiked in complex biological samples. The method is rapid, straightforward and cost-effective, and shows promising in promoting the investigation of the functional roles of 5caC in future study.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
