Hierarchical Mn3O4 Anchored on 3D Graphene Aerogels via C−O−Mn Linkage with Superior Electrochemical Performance for Flexible Asymmetric Supercapacitor

Flexible asymmetric supercapacitors are more appealing in flexible electronics because of high power density, wide cell voltage, and higher energy density than symmetric supercapacitors in aqueous electrolyte. In virtues of excellent conductivity, rich porous structure and interconnected honeycomb structure, three dimensional graphene aerogels show great potential as electrode in asymmetric supercapacitors. However, graphene aerogels are rarely used in flexible asymmetric supercapacitors because of easily re-stacking of graphene sheets, resulting in low electrochemical activity. Herein, flower-like hierarchical Mn₃O₄ and carbon nanohorns are incorporated into three dimensional graphene aerogels to restrain the stack of graphene sheets, and are applied as the positive and negative electrode for asymmetric supercapacitors devices, respectively. Besides, a strong chemical coupling between Mn₃O₄ and graphene via the C-O-Mn linkage is constructed and can provide a good electron-transport pathway during cycles. Consequently, the asymmetric supercapacitor device shows high rate cycle stability (87.8 % after 5000 cycles) and achieves a high energy density of 17.4 μWh cm⁻² with power density of 14.1 mW cm⁻² (156.7 mW cm⁻³) at 1.4 V.     

Triple Frustrated Lewis Pair-Type Reactivity on a Single Rare-Earth Metal Center

Rare-earth metal cations have been used rarely as Lewis-acidic components in the chemistry of frustrated Lewis pairs (FLPs). Herein, we report the first cerium/phosphorus system ( 2 ) employing a heptadentate N₄P₃ ligand, which exhibits triple FLP-type reactivity towards a series of organic substrates, including isocyanates, isothiocyanates, diazomethane, and azides on a single rare-earth Lewis acidic Ce center. This result shows that the Ce center and three P atoms in 2 could simultaneously activate three equivalents of small molecules under mild conditions. This study broadens the diversity of FLPs and demonstrates that rare earth based FLP exhibit unique properties compared with other FLP systems.     

DNAzyme-Mediated Genetically Encoded Sensors for Ratiometric Imaging of Metal Ions in Living Cells

Genetically encoded fluorescent proteins (FPs) have been used for metal ion detection. However, their applications are restricted to a limited number of metal ions owing to the lack of available metal-binding proteins or peptides that can be fused to FPs and the difficulty in transforming the binding of metal ions into a change of fluorescent signal. We report herein the use of Mg²⁺-specific 10–23 or Zn²⁺-specific 8–17 RNA-cleaving DNAzymes to regulate the expression of FPs as a new class of ratiometric fluorescent sensors for metal ions. Specifically, we demonstrate the use of DNAzymes to suppress the expression of Clover2, a variant of the green FP (GFP), by cleaving the mRNA of Clover2, while the expression of Ruby2, a mutant of the red FP (RFP), is not affected. The Mg²⁺ or Zn²⁺ in HeLa cells can be detected using both confocal imaging and flow cytometry. Since a wide variety of metal-specific DNAzymes can be obtained, this method can likely be applied to imaging many other metal ions, expanding the range of the current genetically encoded fluorescent protein-based sensors.     

Eco-friendly solution processing of all-polymer solar cells: Recent advances and future perspective

All-polymer solar cells (all-PSCs) exhibit great potentials in commercial applications. All-PSCs have observed steady performance gains with power conversion efficiency now reaching over 17% in the open literature. However, the current processing of all-PSCs relies predominantly on toxic, chlorinated solvents in moisture-free environments, representing a significant barrier for their commercialization due to the added costs to handle and dispose of such solvents. There is thus an urgent need for safe, environmentally benign, and sustainable ink-based processing methods to produce all-PSC devices reliably and reproducibly in ambient air. In this perspective, fundamental insights on the interplay between all-polymer blend morphologies and eco-friendly solvents are provided. Also, we discuss the recent successes of the green processing methods to manipulate the photoactive morphologies for high-efficiency all-PSCs. In the end, we provide an outlook on future challenges and opportunities of eco-friendly solvents processed all-PSCs for large-scale manufacturing.     

Gorenstein projective bimodules via monomorphism categories and filtration categories

We generalize the monomorphism category from quiver (with monomial relations) to arbitrary finite dimensional algebras by a homological definition. Given two finite dimension algebras A and B, we use the special monomorphism category $\mathsf{Mon}(B,A\text{-}\mathsf{Gproj})$ to describe some Gorenstein projective bimodules over the tensor product of A and B. If one of the two algebras is Gorenstein, we give a sufficient and necessary condition for $\mathsf{Mon}(B,A\text{-}\mathsf{Gproj})$ being the category of all Gorenstein projective bimodules. In addition, if both A and B are Gorenstein, we can describe the category of all Gorenstein projective bimodules via filtration categories. Similarly, in this case, we get the same result for infinitely generated Gorenstein projective bimodules.     

Euler’s partition theorem for all moduli and new companions to Rogers–Ramanujan–Andrews–Gordon identities

The Ramanujan Journal - We generalise Euler’s partition theorem involving odd parts and distinct parts for all moduli and provide new companions to...     

Pharmacokinetic analysis of plasma bicyclol by liquid chromatography–tandem mass spectrometry

Bicyclol is a synthetic drug widely used to treat chronic hepatitis B. This study aimed to develop a selective, sensitive and high‐throughput liquid chromatography–tandem mass spectrometric method for the detection of bicyclol in human plasma. Bicyclol was detected using a multiple reaction monitoring mode, with ammonium adduct ions (m/z 408.2) as the precursor ion and the [M‐CH₃]⁺ ion (m/z 373.1) subjected to demethylation as the product ion. Chromatographic separation was achieved using a Zobax Eclipse XDB‐C₁₈ column with a gradient elution and a mobile phase of 2 mm ammonium formate and acetonitrile. Bicyclol was extracted from plasma matrix by precipitation. A linear detection response was obtained for bicyclol ranging from 0.500 to 240 ng/mL, and the lower limit of quantification was 0.500 ng/mL. The intra‐ and inter‐day precisions were all ≤7.4%, and the accuracies were within ±6.0%. The extraction recovery was >95.9%, and the matrix effects were between 96.0% and 108%. Bicyclol was found to be unstable in human plasma at room temperature, but the degradation was minimized by conducting sample collection and preparation in an ice bath. The validated method was successfully applied to investigate the pharmacokinetics of bicyclol tablets in six healthy Chinese volunteers.     

Simultaneous analysis of current‐use pesticides and their transformation products in water using mixture‐sorbent solid phase extraction and high‐performance liquid chromatography–tandem mass spectrometry

Pesticides have posed significant threats to aquatic ecosystems, yet little is known about their transformation products. The challenge is to simultaneously analyze various pesticides and transformation products in water as they have distinct physicochemical properties. A mix‐mode solid phase extraction method was established to simultaneously analyze current‐use pesticides and their transformation products using a mixture of hydrophile–lipophile balance, weak anion, and cation exchange resins (2:1:1, w/w/w) in combination with high‐performance liquid chromatography and tandem mass spectrometry for chemical quantification. Neutral, acidic, and alkaline methanol were used as the elution solvent. Box‐Behnken design was applied to optimize extraction conditions. Optimal conditions were as follows: sorbent mass, 200 mg; volume of elution solvent, 5 mL × 3; pH 4. The method was validated for compounds at concentrations from 20 to 1000 ng/L in different types of water samples, with recovery being from 43.5 ± 3.1 to 141 ± 35%. Low method detection limits (0.02?5.6 ng/L) implied that the developed method was sensitive. Finally, the method was applied to monitor current‐use pesticides and their transformation products in natural waters. Frequent detection of transformation products of pesticides indicated that their contribution to aquatic risk should not be ignored.