Latest ArticlesAqueous perfluorooctanoic acid (PFOA) elimination has raised significant concerns due to its persistence and bioaccumulation. Although β-PbO2 plate anodes have shown efficient mineralization of PFOA, it remains unclear whether PFOA can be effectively degraded using β-PbO2 reactive electrochemical membrane (REM). Herein, we assessed the performance of Ti/SnO2-Sb/La-PbO2 REM for PFOA removal and proposed a possible degradation mechanism. At a current density of 10 mA/cm2 and a membrane flux of 8500 (liters per square meter per hour, LMH), the degradation efficiency of 10 mg/L PFOA was merely 8.8%, whereas the degradation efficiency of 0.1 mg/L PFOA increased to 96.6%. Although the porous structure of the β-PbO2 REM provided numerous electroactive sites for PFOA, the generated oxygen bubbles in the pores could block the pore channels and adsorb PFOA molecules. These hindered the protonation process and significantly impeded the degradation of high-concentration PFOA. Quenching experiments indicated that •OH played dominant role in PFOA degradation. The electrical energy per order to remove 0.1 mg/L PFOA was merely 0.74 Wh/L, which was almost an order of magnitude lower than that of other anode materials. This study presents fresh opportunities for the electrochemical degradation of low-concentration PFOA using β-PbO2 REM.
Described here is a divergent, biosynthetically inspired synthesis of cochlearol B and ganocin A. Key steps of the synthesis include the chromene unit construction through a biomimetic acid-catalyzed [4 + 2] ring cyclization. A photochemical [2 + 2] cycloaddition was featured to construct the cyclobutane core of cochlearol B. Different skeletal rearrangements of cochlearol B afforded ganocin A, that one of them was Lewis acid mediated epoxide rearrangement and another was DDQ induced cyclobutane formed tetrahydrofuran ring. The described syntheses not only achieved these natural products in an efficient manner, but also provided insight into the biosynthetic relationship between the two different skeletons.
Improving the highly selective and sensitive binding of chemosensor to target guest is always very challenging. In order to solve this issue, herein, the enrichment effect was introduced into the design of chemosensor molecule. A novel bi-fused-macrocyclic host molecule BPN1 was synthesized by bridging a pillar[5]arene and a naphthalene diimide (NDI) group through hydrogen-bond-rich chain. In the BPN1, the naphthalimide side ring is outside the cavity of the pillar[5]arene. In addition, Cr(Ⅵ) greatly threat human health and the environment due to its severe toxicity, and it is very important to develop effective chemosensor for sensitive and selective detection of Cr2O72− or its ion pairs. In this paper, the novel bi-fused-macrocyclic host molecule BPN1 can recognize Cr2O72− with high selectivity and sensitivity. The mechanism of BPN1 recognition of Cr2O72− was studied through experiments and density functional theory (DFT), the results show that BPN1 could supply enrichment effect to bind Cr2O72− through multiple weak interactions such as hydrogen bonds and anion-π, and achieve highly sensitive and selective detection of Cr2O72−. It is a significant and feasible strategy for improve high selectivity and sensitivity of host to specific objects by using the enrichment effect of fused bi-macrocyclic.
Fe-based Fenton agents can generate highly reactive and toxic hydroxyl radicals (·OH) in the tumor microenvironment (TME) for chemodynamic therapy (CDT) with high specificity. However, the low pH environment and insufficient endogenous hydrogen peroxide (H2O2) of the highly efficient Fenton reaction limits its practical application in clinic. Here, a Cu(Ⅱ)-doped mesoporous silica nanoagent (Cu-MSN) with excellent dispersity was successfully developed. After loaded with doxorubicin (DOX) and ascorbate (AA), Cu-MSN@DA was coated with active targeting ligand folic acid (FA), dimethyl maleic an-hydride (DMMA) and carboxymethyl chitosan (CMC) to obtain an active transporting nanoagent (FCDC@Cu-MSN@DA) with tunable charge-reversal property, which is more adaptable to the pH value of TME than Fe-based Fenton agents, and can self-supply exogenous H2O2 by ascorbate to produce more toxic ·OH to trigger the apoptosis of cancer cells. Meanwhile, the high level of glutathione (GSH) in TME can reduce Cu(Ⅱ) to Cu(Ⅰ) by Fenton-like reaction, increasing the generation rate of ·OH and relieving tumor antioxidant ability. The supply of exogenous H2O2 significantly enhanced the synergistic effect of CDT by oxidative damage. Together with DOX-induced cell apoptosis, this novel nanoagent FCDC@Cu-MSN@DA can achieve maximum therapeutic efficacy, creating a new model of safe and effective tumor treatment with high specificity.
The conjugate addition of in-situ generated (aza-)quinone methides (QMs) and indole imine methides (IIMs) emerged as a powerful protocol to access densely functionalized benzenes and indoles. Hydroxybenzyl alcohols, aminobenzhydryl alcohols, and varied indolylmethanols served as most effective precursors for the in-situ generation of such reactive species under acid conditions. The relevant propargylic alcohol has proven to be an elegant precursor to generate the propargylic-QMs and -IIMs via the acid promoted dehydration process, thus enabling diverse challenging remote activation to proceed conjugate 1,6- and 1,8-additions. Moreover, the heteroarene has proven to be workable to transfer the LUMO of the p-QMs and 2-IIMs, thus inducing the remote nucleophilic dearomative additions. The conjugate additions of (aza-)p-QMs and varied IIMs has made significant contribution in the field of remote activation chemistry in past decade. This review summarizes the latest advances of the remote conjugate additions of the in-situ generated QMs and IIMs.
Tumor microenvironment (TME)-activatable probes have been proven to effectively increase signal-to-background ratios (SBRs) and improve the success rate of complete tumor resection. However, many fluorescence probes have to be loaded into a nanocarrier for tumor targeted delivery, which consequently encounters poor drug loading, heterogeneous composition and non-encapsulated drug aggregates occurred during nanoformulation fabrications. Herein, a nitroreductase (NTR)-activated "OFF-ON" near-infrared fluorescence nanoprobe, named NanoBodipy, was synthesized by the spontaneous self-assembling of NTR-responsive dye-polyethylene glycol (PEG) amphiphilic polymer in water. The NTR-responsive dye acted as the hydrophobic segment in the amphiphilic polymer, yielding a homogeneous composition and a high loading of 12.2 wt% (according to calculation) in the synthesized NanoBodipy. The synthesized NanoBodipy can efficiently accumulate in tumors via the enhanced permeability and retention (EPR) effect, enabling non-invasive tumor-targeted fluorescence imaging and guiding complete tumor resection. Once the synthesized NanoBodipy entered the tumor cells, they dissociated and were activated by overexpressed NTR. With the real-time fluorescence guide of NanoBodipy, complete tumor resection surgery was performed successfully.
Relaxor ferroic dielectrics have garnered increasing attention in the past decade as promising materials for energy storage. Among them, relaxor antiferroelectrics (AFEs) and relaxor ferroelectrics (FEs) have shown great promise in term of high energy storage density and efficiency, respectively. In this study, a unique phase transition from relaxor AFE to relaxor FE was achieved for the first time by introducing strong-ferroelectricity BaTiO3 into NaNbO3-BiFeO3 system, leading to an evolution from AFE R hierarchical nanodomains to FE polar nanoregions. A novel medium state, consisting of relaxor AFE and relaxor FE, was identified in the crossover of 0.88NaNbO3–0.07BiFeO3–0.05BaTiO3 ceramic, exhibiting a distinctive core-shell grain structure due to the composition segregation. By harnessing the advantages of high energy storage density from relaxor AFE and large efficiency from relaxor FE, the ceramic showcased excellent overall energy storage properties. It achieved a substantial recoverable energy storage density Wrec ~ 13.1 J/cm3 and an ultrahigh efficiency η ~ 88.9%. These remarkable values shattered the trade-off relationship typically observed in most dielectric capacitors between Wrec and η. The findings of this study provide valuable insights for the design of ceramic capacitors with enhanced performance, specifically targeting the development of next generation pulse power devices.
Anti-inflammatory drugs targeting inflammatory bowel disease (IBD) have attracted considerable attention but still face low therapeutic outcomes and frequent side effects. Astaxanthin (ATX), a natural ketone, possesses potent antioxidant and anti-inflammatory properties. However, it faces problems such as poor water solubility, photothermal instability, and low bioavailability. Here, we employed a supramolecular encapsulation strategy to create a nanoscale oral delivery system for ATX (referred to as FC-ATX NPs) by coupling fucoidan (FUC) with chitosan oligosaccharides (COS). The obtained FC-ATX NPs exhibited a particular "bean pod" structure with uniform size, good encapsulation efficiency, excellent physical and chemical stability, pH-triggered intestinal targeted slow-release properties, and potent antioxidant capacity. In vitro cell culture experiments showed that FC-ATX NPs promoted cellular uptake and scavenged excessive intracellular reactive oxygen species (ROS). In mouse models of colitis, FC-ATX NPs enhanced the drug absorption of intestinal epithelial cells and effectively accumulated at the site of inflammation. This work provides an efficient approach to enhance the bioavailability of ATX and has excellent application potential as an oral targeted delivery system for colitis therapy.
Qubit, as the basic unit of quantum operations, has at least two quantum states for superposition. Diamond itself has no superimposable quantum states, but after injecting N atoms, the resulted nitrogen-vacancy centers form excellent-performance qubits. For the same purpose, we can also obtain qubits by modifying the matrix without effective quantum states. HKUST-1 ({Cu3(BTC)2(H2O)3}, BTC = 1,3,5-benzene-tricarboxylate) with S = 0 ground state is electron paramagnetic resonance (EPR) silent, so it is not a qubit candidate. However, the spontaneously hydrolyzed HKUST-1 produces dilute uncoupled CuⅡ ions with S = 1/2. In this paper, we utilized the hydrolysis products of HKUST-1 to obtain qubits and assembled a core-shell structural HKUST-1@ZIF-8 by ZIF-8 ({Zn(mim)2}, mim = 2-methylimidazole) coated over HKUST-1 for controlling the hydrolysis. The experimental results clearly show that the qubits come from hydrolyzed CuⅡ ions. Furthermore, the dilute uncoupled CuⅡ ions in this assembly can effectively reduce the decoherence of qubits. The EPR studies show that the T2 of this compound is 1067 ns at 10 K.
Chemical sensor arrays can obtain more comprehensive analyte information through high-dimensional data. It is of great significance in the analysis of multi-component complex samples. This review summarizes the development and status of chemical sensor arrays. We focused on the design of chemical sensor arrays based on various sensing materials. In addition, several pattern recognition methods in chemometrics are introduced. And applications of chemical sensor arrays in food monitoring, medical diagnosis, and environmental monitoring are illustrated. Based on the analysis of the limitations of current sensor array technology, the direction of the array is also predicted. This review aims to help the broad readership understand the research state of chemical sensor arrays and their development prospects.
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