Radiation-induced grafting of acrylamide onto guar gum in aqueous medium: Synthesis and characterization of grafted polymer guar-g-acrylamide

Mutual radiation grafting technique has been applied to carry out grafting of acrylamide (AAm) onto guar gum (GG) using high-energy Co⁶⁰ γ radiation to enhance its flocculating properties for industrial effluents. The grafted product was characterized using analytical probes like elemental analysis, thermal analysis, Fourier transformed infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The grafting extent was observed to decrease with the dose rate and increase with the concentration of AAm. Thermo gravimetric analysis (TGA) of grafted and ungrafted samples indicated better stability of grafted product. γ and microwave radiation effect on grafted and virgin GG has also been reported.     

牛血清白蛋白在NVP/HEMA无规共聚物水凝胶上的吸附研究

合成了不同含水量的N-乙烯吡咯烷酮(NVP)／甲基丙烯酸-β-羟乙酯(HEMA)共聚物水凝胶．研究了温度、pH值，蛋白质初浓度及离子强度等因素对牛血清白蛋白吸附性能的影响．采用紫外分光光度法测定BSA的吸附量．结果表明，蛋白质初浓度越高．温度越高，离子强度越大；蛋白质内部更多的疏水性氧基酸残基暴露于外部．吸附量增加：在等电点pH=4．7附近蛋白质沉积量最大．     

Improved enzyme immobilization for enhanced bioelectrocatalytic activity of porous electrodes

Porous electrodes with increased surface area have been prepared using a template route via colloidal crystals. The ordered porous structure and the interconnections between the pores have been quantitatively characterized by Focused Ion Beam Tomography. The internal surfaces of the electrodes have been biofunctionalized with two enzymatic systems for glucose oxidation. In order to increase significantly the stability, the biocatalysts have been immobilized either by crosslinking or by incorporation in an electrodeposition paint. The modified porous electrodes show an increased overall signal and therefore a better detection limit and a higher sensitivity when used as sensors, and a potentially higher power output when employed in biofuel cells.     

SEI layer-forming additives for LiNi0.5Mn1.5O4/graphite 5 V Li-ion batteries

This study demonstrates that proper SEI layer on graphite anode is essential in LiNi_0.5Mn_1.5O₄(LNMO)/graphite 5 V lithium-ion batteries. Succinic anhydride (SA) and 1,3-propane sultone (PS) were found to greatly extend cycle life and suppress swelling behavior of LNMO/graphite cells. The benefits of SA and PS were ascribed not only to the stable SEI layer they form on graphite but also to their stability toward the oxidation at high voltage. Using 1 M LiPF₆ EC/EMC (1/2, v/v) solutions with SA and PS, LNMO/graphite Al-laminated pouch cell with nominal capacity of 600 mA h exhibited about 80% capacity retention after 100 cycles. This is the first report on the successful LNMO/graphite 5 V LIB to our best knowledge.     

阴离子交换树脂分离富集水中痕量镉

先用草酸处理水样中的镉离子,生成的[Cd(C2O4)2]2-络阴离子通过强碱性阴离子交换树脂分离富集,最后用火焰原子吸收分光光度法测定了水样中的痕量镉。该法简便,选择性好,富集倍数高,应用于实际水样的检测,回收率为98%~102%,结果令人满意。     

A mini-review on MXenes as versatile substrate for advanced sensors

MXenes have emerged as versatile 2D materials that are already gaining paramount attention in the areas of energy,catalyst,electromagnetic shielding,and sensors.The unique surface chemistry,graphene-like mo rphology,high hydrophilicity,metal-like conductivity with redox capability identifies MXenes,as an ideal material for surface-related applications.This short review summarizes the most recent reports that discuss the potential application of MXenes and their hybrids as a transducer material for advanced sensors.Based on the nature of transducing signals,the discussion is categorized into three sections,which include electrochemical(bio) sensors,gas sensors,and finally,electro-chemiluminescence fluorescent sensors.The review provides a concise summary of all the analytical merits obtained subsequent to the use of MXenes,followed by endeavors that have been made to accentuate the future perspective of MXenes in sensor devices.     

Emission spectroscopic monitoring of particle composition,size and transport in laser ablation inductively coupled plasma spectrometry

The spectroscopic line emissions of copper and zinc from atomized particles generated by orthogonal pre-pulse laser ablation of brass and transported from the ablation cell through tubes into an ICP have been simultaneously measured end-on with fast photomultipliers. It was shown that simultaneous line monitoring of major elements provides not only information on the aerosol transport in laser ablation ICP-spectrometry, but also on the ratios of small to single larger particles and their respective elemental compositions and, therefore, on possible elemental fractionation problems. Furthermore, the spectroscopic information can be easily exploited for proper adjustment of the laser fluence in order to minimize the production of large particles, to improve the transport efficiency and to reduce the noise of analytical signals in laser ablation ICP-spectrometry. The present particular experiment on orthogonal pre-pulse laser ablation of brass confirms the recent finding that such kind of double-pulse arrangement produces predominantly ultra-fine particles. Individual brass particles with diameters ≳ 250 nm could be analyzed. They showed large Zn depletions as expected. Finally, strong accumulations of aerosol particles were found in the ablation cell used even at low laser pulse frequencies.     

吡咯烷酮酸性离子液体的合成及其对酯化反应的催化活性

合成并表征了 2-吡咯烷酮硫酸氢盐([Hnhp]HSO4)、 1-甲基-2-吡咯烷酮硫酸氢盐([Hnmp]HSO4)、 1-甲基咪唑硫酸氢盐([Hmim]HSO4)、 1-(3-磺酸基)-丙基-3-甲基咪唑硫酸氢盐([C3SO3Hmim]HSO4)和1-(3-磺酸基)-丙基-2-吡咯烷酮硫酸氢盐([C3SO3Hnhp]HSO4)等以HSO-4为阴离子的质子酸离子液体,并以乙酸和正丁醇的酯化反应考察了这些离子液体的催化活性.结果表明,当n(n-BuOH):n(MeCO2H):n([C3SO3Hnhp]HSO4)=1.2:1:0.005,反应温度为120 ℃和反应时间为 1 h 时,酯收率可达99%以上;反应结束后离子液体与酯产物可分成两相,而且该离子液体重复使用8次,催化活性没有明显下降.探讨了阳离子结构及Brnsted酸性对催化活性的影响,考察了离子液体与酯化反应相关组分的互溶性.结果表明,离子液体的分相性能对催化效果有较大的影响,离子液体的催化活性与其酸性、溶解性密切相关.     

Simultaneously achieving high capacity storage and multilevel anti-counterfeiting using electrochromic and electrofluorochromic dual-functional AIE polymers

With the advent of the big data era, information storage and security are becoming increasingly important. However, high capacity information storage and multilevel anti-counterfeiting are typically difficult to achieve simultaneously. To address this challenge, herein, two electrochromic and electrofluorochromic dual-functional polymers with aggregation-induced emission (AIE) characteristics were rationally designed and facilely prepared. Upon applying voltages, the absorption and fluorescence spectra of the AIE polymers can undergo reversible changes, accompanied by variation of their color and emission. By utilizing the controllable characteristics of the polymers, dual-mode display devices were fabricated via a simple spraying technique. More interestingly, a four-dimensional color code device was constructed by adding color change multiplexing to the two-dimensional space, thereby achieving high capacity information storage. Moreover, the color code device can also be applied in the multilevel anti-counterfeiting area. The encrypted information can be dynamically converted under different voltages. Thus, the AIE polymers show great promise for applications in multidimensional information storage and dynamic anti-counterfeiting, and the design strategy may provide a new avenue for advanced information storage and high security technology.

By using electrical stimuli-responsive AIE polymers, dual-mode display devices, multidimensional information storage and anti-counterfeiting devices were constructed.     

Universal and high-fidelity DNA single nucleotide polymorphism detection based on a CRISPR/Cas12a biochip

Single nucleotide polymorphisms (SNPs) are associated with many human diseases, so accurate and efficient SNP detection is of great significance for early diagnosis and clinical prognosis. This report proposes a universal and high-fidelity genotyping method in microfluidic point-of-care equipment based on the clustered regularly interspaced short palindromic repeat (CRISPR) system. Briefly, by systematically inserting the protospacer-adjacent-motif (PAM) sequence, we improved the universality of the CRISPR/Cas12a based SNP detection; by removing the complementary ssDNA and introducing an additional nucleotide mismatch, we improved the sensitivity and specificity. We preloaded the CRISPR/Cas12a reagents into the point-of-care biochip for automating the process, increasing the stability and long-term storage. This biochip enables us to rapidly and conveniently detect the genotypes within 20 min. In a practical application, the CRISPR/Cas12a biochip successfully distinguished three genotypes (homozygous wild type; the homozygous mutant type; and the heterozygous mutant type) of the CYP1A1*2 (A4889G, rs1048943), CYP2C19*2 (G681A, rs4244285), CYP2C9*3 (A1075C, rs1057910), and CYP2C19*3 (G636A, rs4986893) genes related to multiple cancers from 17 clinical blood samples. This CRISPR/Cas12a-based SNP genotyping method, being universal, accurate, and sensitive, will have broad applications in molecular diagnostics and clinical research.

A universal and high-fidelity genotyping method based on the clustered regularly interspaced short palindromic repeat (CRISPR) system was performed on the microfluidic point-of-care equipment.