A Compartmentalized Nanoreactor Formed by Interfacial Hydrogelation for Cascade Enzyme Catalytic Therapy

Some cellular enzymatic pathways are located within a single organelle, while most others involve enzymes that are located within multiple compartmentalized cellular organelles to realize the efficient multi-step enzymatic process. Herein, bioinspired by enzyme-mediated biosynthesis and biochemical defense, a compartmented nanoreactor (Burr-NCs@Gl^SOD) was constructed through a self-confined catalysis strategy with burr defect-engineered molybdenum disulfide/Prussian blue analogues (MoS₂/PBA) and an interfacial diffusion-controlled hydrogel network. The specific catalytic mechanism of the laccase-like superactivity induced hydrogelation and cascade enzyme catalytic therapy were explored. The confined hydrogelation strategy introduces a versatile means for nanointerface functionalization and provides insight into biological construction of simulated enzymes with comparable activity and also the specificity to natural enzymes.     

Fused Indacene Dimers

Polycyclic hydrocarbons consisting of two or more directly fused antiaromatic subunits are rare due to their high reactivity. However, it is important to understand how the interactions between the antiaromatic subunits influence the electronic properties of the fused structure. Herein, we present the synthesis of two fused indacene dimer isomers: s-indaceno[2,1-a]-s-indacene ( s -ID ) and as-indaceno[3,2-b]-as-indacene ( as -ID ), containing two fused antiaromatic s-indacene or as-indacene units, respectively. Their structures were confirmed by X-ray crystallographic analysis. ¹H NMR/ESR measurements and DFT calculations revealed that both s -ID and as -ID have an open-shell singlet ground state. However, while localized antiaromaticity was observed in s -ID , as -ID showed weak global aromaticity. Moreover, as -ID exhibited a larger diradical character and a smaller singlet-triplet gap than s -ID . All the differences can be attributed to their distinct quinoidal substructures.     

Formation of a three-dimensional bispyridyl based metal-organic architecture containing unique Ag...Ag （d^10-d^10） interactions

A novel co-ordination polymer based on IB metal thiocyanates, [Ag2（NCS）2（4,4＇-bipy）]. （1）（4,4＇-bipy = 4,4＇-bispyridine）, has been synthesized by the pre-assembly method and characterized by X-ray crystallography. The complex exists as a three- dimensional network consisting of （AgSCN）. undulating layers linked by 4,4＇-bipy bridges.     

LIBS技术在土壤重金属污染快速测量中的应用

激光诱导击穿光谱(laser-induced breakdown spectroscopy,LIBS)作为一种很有前景的分析和测量技术在过去的10多年中已经显现出来.本文介绍了激光诱导击穿光谱的工作原理和定量定性分析的理论基础,综述了LIBS技术在土壤重金属As、Cd、Cr、Hg、Pb 和Zn等污染快速测量中的应用和仪器研究进展,分析了LIBS应用在该领域中存在的主要问题,对未来基于LIBS快速检测土壤重金属污染需要解决的定量测量和检测限等关键问题进行了探讨.     

Synthesis of Carbon Nanofibers for Mediatorless Sensitive Detection of NADH

Highly sensitive amperometric detection of dihydronicotinamide adenine dinucleotide (NADH) by using novel synthesized carbon nanofibers (CNFs) without addition of any mediator has been proposed. The CNFs were prepared by combination of electrospinning technique with thermal treatment method and were applied without any oxidation pretreatment to construct the electrochemical sensor. In amperometric detection of NADH, a linear range up to 11.45 μM with a low detection limit of 20 nM was obtained with the CNF‐modified carbon paste electrode (CNF‐CPE). Good selectivity was exhibited for the simultaneous detection of NADH and its common interferent of ascorbic acid (AA) by differential pulse voltammogram. The attractive electrochemical performance and the versatile preparation process of the CNF‐CPE made it a promising candidate for designing effective NADH sensor.     

Synthesis, crystal structure, and optical properties of a novel rare-earth complex Nd(C2F5COO)3 · Phen

A novel neodymium pentafluoropropionate binuclear complex, Nd(C₂F₅COO)₃ · Phen (Phen: 1,10-phenanthroline), was synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, FT-IR spectra, UV–Vis–NIR absorption, and PL spectra. Single-crystal data show that the complex bears centrosymmetric dinuclear structure with a planar ligand configuration. Four carboxylato groups act as η²-chelate-μ²-carboxylato-k¹O:k¹O′-bridge-ligands, the other two occupy the terminal position as monodentate ligands. At the same time, the C–O distances appear averaged which indicate the three atoms of carboxylato forming electron-conjugate system. Hydrogen bond and π–π-stacking link the binuclear to two-dimensional sheet. Optical spectra exhibit the complex possesses typical Nd(III) ion absorption and photoluminescence emission.     

On the dual of a Coulter–Matthews bent function

Coulter–Matthews (CM) bent functions are from to defined by , where and (α,2n)=1. It is not known if these bent functions are weakly regular in general. In this paper, we show that when n is even and α=n+1 (or n−1), the CM bent function is weakly regular. Moreover, we explicitly determine the dual of the CM bent function in this case. The dual is a bent function not reported previously.     

Design of a Fully Non-Fused Bulk Heterojunction toward Efficient and Low-Cost Organic Photovoltaics

To modulate the miscibility between donor and acceptor materials both possessing fully non-fused ring structures, a series of electron acceptors (A4T-16, A4T-31 and A4T-32) with different polar functional substituents were synthesized and investigated. The three acceptors show good planarity, high conformational stability, complementary absorption and energy levels with the non-fused polymer donor (PTVT-BT). Among them, A4T-32 possesses the strongest polar functional group and shows the highest surface energy, which facilitates morphological modulation in the bulk heterojunction (BHJ) blend. Benefiting from the proper morphology control method, an impressive power conversion efficiency (PCE) of approaching 16.0 % and a superior fill factor over 0.795 are achieved in the PTVT-BT : A4T-32-based organic photovoltaic cells with superior photoactive materials price advantage, which represent the highest value for the cells based on the non-fused blend films. Notably, this cell maintains ≈84 % of its initial PCE after nearly 2000 h under the continuous simulated 1-sun-illumination. In addition, the flexible PTVT-BT : A4T-32-based cells were fabricated and delivered a decent PCE of 14.6 %. This work provides an effective molecular design strategy for the non-fused non-fullerene acceptors (NFAs) from the aspect of bulk morphology control in fully non-fused BHJ layers, which is crucial for their practical applications.     

A Conformational Restriction Strategy for the Control of CRISPR/Cas Gene Editing with Photoactivatable Guide RNAs**

The CRISPR/Cas system is one of the most powerful tools for gene editing. However, approaches for precise control of genome editing and regulatory events are still desirable. Here, we report the spatiotemporal and efficient control of CRISPR/Cas9- and Cas12a-mediated editing with conformationally restricted guide RNAs (gRNAs). This approach relied on only two or three pre-installed photo-labile substituents followed by an intramolecular cyclization, representing a robust synthetic method in comparison to the heavily modified linear gRNAs that often require extensive screening and time-consuming optimization. This tactic could direct the precise cleavage of the genes encoding green fluorescent protein (GFP) and the vascular endothelial growth factor A (VEGFA) protein within a predefined cutting region without notable editing leakage in live cells. We also achieved light-mediated myostatin (MSTN) gene editing in embryos, wherein a new bow-knot-type gRNA was constructed with excellent OFF/ON switch efficiency. Overall, our work provides a significant new strategy in CRISPR/Cas editing with modified circular gRNAs to precisely manipulate where and when genes are edited.     

Stereodivergent Construction of 1,3-Chiral Centers via Tandem Asymmetric Conjugate Addition and Allylic Substitution Reaction

Herein, we report a synthesis of cyclohexanones bearing multi-continuous stereocenters by combining copper-catalyzed asymmetric conjugate addition of dialkylzinc reagents to cyclic enones with iridium-catalyzed asymmetric allylic substitution reaction. Good to excellent yields, diastereoselectivity and enantioselectivity can be obtained. Unlike the stereodivergent construction of adjacent stereocenters (1,2-position) reported in the literature, the current reaction can achieve the stereodivergent construction of nonadjacent stereocenters (1,3-position) by a proper combination of two chiral catalysts with different enantiomers.