Fluorescence sensing and intracellular imaging for hydroxyl radical using coumarin-modified cyclodextrin derivatives

A coumarin-methyl-β-cyclodextrin (CCA-MCD) was synthesised. Fluorescence studies showed that CCA-MCD could successfully sense hydroxyl radicals (√OH) in water and it had a specific fluorescence response to √OH over other free radicals. Further study showed that it could monitor intracellular √OH as well. These findings suggest that CCA-MCD can be used as a cell-permeable fluorescence sensor to study the function of √OH in biological processes.     

Palladium‐Catalysed C(sp3)−H Glycosylation for the Synthesis of C‐Alkyl Glycoamino Acids

We have developed a highly efficient and practical approach for palladium‐catalyzed trifluoroacetate‐promoted N‐quinolylcarboxamide‐directed glycosylation of inert β‐C(sp³)?H bonds of N‐phthaloyl α‐amino acids with glycals under mild conditions. For the first time, C(sp³)?H activation for glycosylation was achieved to build C‐alkyl glycosides. This method facilitates the synthesis of various β‐substituted C‐alkyl glycoamino acids and offers a tool for glycopeptide synthesis.     

Copper-Catalyzed Deaminative Difluoromethylation

The difluoromethyl group (CF₂H) is considered to be a lipophilic and metabolically stable bioisostere of an amino (NH₂) group. Therefore, methods that can rapidly convert an NH₂ group into a CF₂H group would be of great value to medicinal chemistry. We report herein an efficient Cu-catalyzed approach for the conversion of alkyl pyridinium salts, which can be readily synthesized from the corresponding alkyl amines, to their alkyl difluoromethane analogues. This method tolerates a broad range of functional groups and can be applied to the late-stage modification of complex amino-containing pharmaceuticals.     

Surface Reconstruction of Ultrathin Palladium Nanosheets during Electrocatalytic CO2 Reduction

A surface reconstructing phenomenon is discovered on a defect-rich ultrathin Pd nanosheet catalyst for aqueous CO₂ electroreduction. The pristine nanosheets with dominant (111) facet sites are transformed into crumpled sheet-like structures prevalent in electrocatalytically active (100) sites. The reconstruction increases the density of active sites and reduces the CO binding strength on Pd surfaces, remarkably promoting the CO₂ reduction to CO. A high CO Faradaic efficiency of 93 % is achieved with a site-specific activity of 6.6 mA cm⁻² at a moderate overpotential of 590 mV on the reconstructed 50 nm Pd nanosheets. Experimental and theoretical studies suggest the CO intermediate as a key factor driving the structural transformation during CO₂ reduction. This study highlights the dynamic nature of defective metal nanosheets under reaction conditions and suggests new opportunities in surface engineering of 2D metal nanostructures to tune their electrocatalytic performance.     

The review of Lab-on-PCB for biomedical application

Prevention of infectious diseases, diagnosis of diseases, and determination of treatment options all rely on biosensors to detect and analyze biomarkers, which are usually divided into four parts: cell analysis, biochemical analysis, immunoassay, and molecular diagnosis. However, traditional biosensing devices are expensive, bulky, and require a lot of time to detect, which also limited its application in resource-limited areas. In recent years, Lab-on-PCB, which combines biosensing technology and PCB technology, has been widely used in biomedical applications due to its high integration, personalized design, and easy mass production. Among these Lab-on-PCB sensing devices, the PCB circuit plays an important role. It can be directly used as a resistance sensor to count cells, and also used as a control device to automatically control the detection device. Flexible PCBs can be used to make wearable medical biosensors. In addition, due to the high degree of integration of the PCB circuit, Lab-on-PCB can perform multiple inspections on the same platform, which reduces the inspection time equivalently. Therefore, in this review paper, we discuss the application of Lab-on-PCB in four analysis methods of cell analysis, biochemical analysis, immunoassay, and molecular diagnosis, and give some suggestions for improvement and future development trends at the end.     

聚阴离子型钠离子电池正极材料的研究进展

作为钠离子电池正极材料的体系之一,聚阴离子型化合物具有成本低廉和安全性高的优点,适合于大规模固定式储能系统。实时平衡电网电力供需水平对正极材料的倍率性能提出了更高的要求,而聚阴离子材料虽然存在离子扩散通道,但缺乏电子传输路径,导致其动力学性能不佳。为了挖掘影响聚阴离子型正极动力学性能的因素,本文以结构为基础,对影响聚阴离子正极离子扩散行为的本征原因作了阐述,再从表面修饰和形态设计入手,对目前研究较多的改善电极表面及界面处离子和电子扩散的策略作了总结与点评,然后从材料的分级结构回归到鲜见报导的元素掺杂和取代,从本质上提出优化动力学性能的方案,并展望了进一步提高正极材料倍率性能的方向。本文可为高倍率的聚阴离子型正极材料及其他材料的开发提供基本理论和实践依据。     

炸药爆轰温度的瞬时多光谱测量

从多光谱测温的基本原理出发,对瞬时多光谱爆温测量装置的工作原理、系统结构、爆温计算以及测量过程中可能引入的误差和进一步提高测量精度的方法进行了阐述和分析.利用该装置对液体炸药硝基甲烷的爆温进行了实际测量,取得了满意的测量结果,其爆温为3672 K,扩展不确定度为100 K(k＝2),该温度下的光谱发射率为0.69.     

Cooperative catalysis in highly enantioselective Mannich-type three-component reaction of a diazoacetophenone with an alcohol and an imine

A highly enantioselective three-component reaction of a diazoacetophenone, an alcohol, and an imine catalyzed cooperatively by Rh(2)(OAc)(4) and BINOL-derived chiral phosphoric acid has been developed for the synthesis of chiral β-amino-α-hydroxyl ketones in good yield with excellent diastereo and enantio selectivity.     

Synthesis of Amide Compounds of Ferulic Acid and Their Association with Bovine Serum Albumin

ABSTRACT

In this work, three new amide compounds of ferulic acid (FA) were synthesized. The fluorescence and ultraviolet spectroscopy were explored to study the interactions between three amide compounds of FA and bovine serum albumin (BSA) under imitated physiological conditions. The experimental results showed that the fluorescence quenching mechanism between BSA and three amide compounds of FA were mainly static quenching and nonradiation energy transfer at 25°C, 30°C, and 37°C. The Stern–Volmer quenching constants, the binding constants, and the number of binding sites and corresponding thermodynamic parameters ΔH, ΔG, and ΔS were calculated at different temperatures. From the thermodynamic parameters, we concluded that the action force was mainly a hydrophobic interaction. According to the F?rster theory of nonradiation energy transfer, the binding distances (r) between BSA and amide compounds are less than 7 nm. Furthermore, the effects of amide compounds on the conformation of BSA were analyzed using synchronous fluorescence spectroscopy.