In-situ grown metal organic framework synergistic system for the enantioseparation of three drugs in open tubular capillary electrochromatography

Metal organic frameworks have received great attention as the chiral stationary phase for racemic drug separation because of their fascinating structures and properties. However, the most homochiral metal organic frameworks were constructed by rare and precious chiral organic ligands. In this work, an achiral metal organic framework, together with a natural chiral selector carboxymethyl β-cyclodextrin built a synergistic separation system in the open tubular capillary electrochromatography. The novel coated columns were developed by inducing metal organic framework nanoparticles to grow on the imidazolyl functional capillary inner wall. The baseline separations of hydroxychloroquine, ofloxacin, and atenolol were achieved in the synergistic separation system. The effects of the concentration of chiral selector, pH, voltage, and the concentration of organic additives were studied. Compared with chiral selector auxiliary bare capillary, the resolutions of three drugs were remarkably improved. The relative standard deviations for the retention time of intraday (n = 6), interday (n = 6), and column-to-column were less than 2.1, 2.6, and 5.2%, respectively. These results demonstrate that affordable synergistic separation systems are prospective for racemic drug enantioseparation in capillary electrochromatography.     

A Universal DNA Aptamer that Recognizes Spike Proteins of Diverse SARS-CoV-2 Variants of Concern

We report on a unique DNA aptamer, denoted MSA52, that displays universally high affinity for the spike proteins of wildtype SARS-CoV-2 as well as the Alpha, Beta, Gamma, Epsilon, Kappa, Delta and Omicron variants. Using an aptamer pool produced from round 13 of selection against the S1 domain of the wildtype spike protein, we carried out one-round SELEX experiments using five different trimeric spike proteins from variants, followed by high-throughput sequencing and sequence alignment analysis of aptamers that formed complexes with all proteins. A previously unidentified aptamer, MSA52, showed K_d values ranging from 2 to 10 nM for all variant spike proteins, and also bound similarly to variants not present in the reselection experiments. This aptamer also recognized pseudotyped lentiviruses (PL) expressing eight different spike proteins of SARS-CoV-2 with K_d values between 20 and 50 pM, and was integrated into a simple colorimetric assay for detection of multiple PL variants. This discovery provides evidence that aptamers can be generated with high affinity to multiple variants of a single protein, including emerging variants, making it well-suited for molecular recognition of rapidly evolving targets such as those found in SARS-CoV-2.     

稀释剂粉末压片-X射线荧光光谱法测定锑矿石中锑及主量组分

利用X射线荧光光谱仪结合稀释剂粉末压片法来测定锑矿石中锑及主量组分。通过稀释剂的加入,减弱了样品的基体效应。人工配制了一系列具有浓度梯度的样品来解决标准样品个数偏少的问题。方法简便、实用,具有较高的精密度和准确度,测定结果满足实际工作需要。方法的相对标准偏差(RSD)为0.19%～2.0%,与常规分析结果基本一致。     

Synthesis of a Porous [14]Annulene Graphene Nanoribbon and a Porous [30]Annulene Graphene Nanosheet on Metal Surfaces

The electrical and mechanical properties of graphene-based materials can be tuned by the introduction of nanopores, which are sensitively related to the size, morphology, density, and location of nanopores. The synthesis of low-dimensional graphene nanostructures containing well-defined nonplanar nanopores has been challenging due to the intrinsic steric hindrance. Herein, we report the selective synthesis of one-dimensional (1D) graphene nanoribbons (GNRs) containing periodic nonplanar [14]annulene pores on Ag(111) and two-dimensional (2D) porous graphene nanosheet containing periodic nonplanar [30]annulene pores on Au(111), starting from a same precursor. The formation of distinct products on the two substrates originates from the different thermodynamics and kinetics of coupling reactions. The reaction mechanisms were confirmed by a series of control experiments, and the appropriate thermodynamic and kinetic parameters for optimizing the reaction pathways were proposed. In addition, the combined scanning tunneling spectroscopy (STS) and density functional theory (DFT) calculations revealed the electronic structures of porous graphene structures, demonstrating the impact of nonplanar pores on the π-conjugation of molecules.     

Organosulfonate Counteranions—A Trapped Coordination Polymer as a High-Output Triboelectric Nanogenerator Material for Self-Powered Anticorrosion

Selection of the friction electrode materials is crucial to the performance of a triboelectric nanogenerator (TENG). In the present study, a metal–organic coordination complex containing organosulfonate counteranions with electron-donating ability was synthesized through the coordination-driven self-assembly approach under mild reaction conditions and was chosen as a positive electrode material to construct a triboelectric nanogenerator, exhibiting high-output performance with a peak value of short circuit current density of 98.6 μA and an output voltage of 1180 V. As a practical application, it was shown to light up 1488 commercial green LEDs and power an anticorrosion system device to protect metals from corrosion.     

Synthesis of 2-phenoxyl-2-oxo-1,4,2-oxazaphosphinanes from a three component reaction

Abstract

A one-pot synthetic strategy was developed for the synthesis of heterocyclic 1,4,2-oxazaphosphinanes via a three component Kabachnik-Fields reaction of 2-aminophenol, diphenyl H-phosphonate and carbonyl compounds. Through this newly developed method, 12 organophosphorus heterocycles and 2 related chrysin derivatives were synthesized with high yields. The target compounds were characterized by ¹H, ³¹P and 13C NMR and MS.     

Gold nanoparticles as dehydrogenase mimicking nanozymes for estradiol degradation

Small gold nanoparticles can mimic dehydrogenase activity to catalyze estradiol (E2) oxidation to estrone (E1), extending the range of nanozyme catalysis to environmentally and biologically important substrates.     

扩频雷达探测一阶海洋回波

利用扩频通信良好的抗干扰性和低功率谱密度下工作的特点,本文把扩频技术引入高频海洋探测雷达来探测海洋一阶回波,研究结果表明,该技术对回波质量无不良影响,同时可降低雷达发射功率,增加雷达探测距离．     

偏心率效应对金属圆柱管轴压性能的影响

用含有偏心率因子的直链塑性铰叠缩模型来分析金属圆柱管轴向压缩能量吸收，根据能量原理推导了瞬时载荷，从而获得压缩过程的载荷-位移曲线．讨论了偏心率对平均压缩载荷和载荷-位移曲线形貌的影响．实验结果与模型分析符合得很好．     

荧光素单磷酸酯的合成和其应用于荧光光度法测定酸性磷酸酯酶

本文新合成了荧光素单磷酸酯,通过元素分析、红外、热谱确定了其结构,探讨了其生成机理,并将其应用到酸性磷酸酯的荧光分析,深入研究了它与酸性磷酸酯酶之间反应的条件、检测此酶的线性范围、检测限和米氏常效.