一种Fe3+荧光探针的合成及其检测性能研究

金属离子的高效检测对于人类健康和环境保护极其重要。本文通过对甲基苯磺酸催化下3-脱氢莽草酸甲酯与若丹明6G乙二胺缩合的芳构化反应合成了一种检测Fe~(3+)的荧光探针分子Rh M606。该探针分子在乙醇溶液中特异性地与Fe~(3+)络合,导致若丹明内酰胺开环,在553nm处出现强的荧光发射峰。该荧光探针对Fe~(3+)具有良好的选择性,可定量检测水中的Fe~(3+),检测限为3. 93μmol/L。     

Synthesis of 2-aminothiazoles from styrene derivatives mediated by 1,3-dibromo-5,5-dimethylhydrantoin (DBH)

An efficient procedure for the synthesis of 2-aminothiazoles via DBH-mediated oxidative cyclization of styrenes and thioureas is reported. Various alkenes were successfully transformed to the corresponding 2-aminothiazoles in yields of 10–81% via a two-step one-pot manner using DBH as both the bromine source and oxidant. The method can be readily carried out in gram-scale and successfully applied to the synthesis of anti-inflammatory drug fanetizole using styrene as starting material.     

Hybrid organic-inorganic phenyl monolithic column for capillary electrochromatography

A novel hybrid organic-inorganic silica-based monolithic column possessing phenyl ligands for reversed-phase (RP) capillary electrochromatography (CEC) is described. The monolithic stationary phase was prepared by in situ co-condensation of tetraethoxysilane (TEOS) with phenyltriethoxysilane (PTES) via a two-step catalytic sol-gel procedure to introduce phenyl groups distributed throughout the silica matrix for chromatographic interaction. The hydrolysis and condensation reactions of precursors were chemically controlled through pH variation by adding hydrochloric acid and dodecylamine, respectively. The structural property of the monolithic column can be easily tailored through adjusting the composition of starting sol solution. The effect of PTES/TEOS ratios on the morphology of the created stationary phases was investigated. A variety of neutral and basic analytes were used to evaluate the column performance. The CEC columns exhibited typical RP chromatographic retention mechanism for neutral compounds and had improved peak shape for basic solutes.     

Chinese Propolis Suppressed Pancreatic Cancer Panc-1 Cells Proliferation and Migration via Hippo-YAP Pathway

Pancreatic cancer is one of the most malignant cancers with high mortality. Therefore, it is of great urgency to develop new agents that could improve the prognosis of Pancreatic cancer patients. Chinese propolis (CP), a flavonoid-rich beehive product, has been reported to have an anticancer effect. In this study, we applied CP to the human Pancreatic cancer cell line Panc-1 to verify its impact on tumor development. CP induced apoptosis in Panc-1 cells from 12.5 µg/mL in a time- and dose-dependent manner with an IC₅₀ value of approximately 50 µg/mL. Apoptosis rate induced by CP was examined by Annexing FITC/PI assay. We found that 48 h treatment with 50 µg/mL CP resulted in 34.25 ± 3.81% apoptotic cells, as compared to 9.13 ± 1.76% in the control group. We further discovered that the Panc-1 cells tended to be arrested at G2/M phase after CP treatment, which is considered to contribute to the anti-proliferation effect of CP. Furthermore, our results demonstrated that CP suppressed Panc-1 cell migration by regulating epithelial–mesenchymal transition (EMT). Interestingly, the Hippo pathway was activated in Panc-1 cells after CP treatment, serving as a mechanism for the anti-pancreatic cancer effect of CP. These findings provide a possibility of beehive products as an alternative treatment for pancreatic cancer.     

新型Ti3C2 MXene的化学制备及基于MXene忆阻器特性与机理

阻变器件是一种微电子器件,具有阻值可在两个甚至两个以上的阻态之间重复变化的特点。忆阻器作为新型的阻变器件,具有可连续变化的丰富阻态。近年来因其具备简单的二端结构、高集成度以及低工作电压等特性,在新型非易失性存储以及构建神经形态系统等方面被广泛研究。但其在实现应用的过程中仍存在着稳定性较差等问题。近期一些工作证明了二维材料如氧化石墨烯在优化忆阻器性能方面具备良好的应用潜力。MXene是一种具备类似石墨烯结构的新型二维过渡金属碳/氮化物,因其具备二维层状结构显现出特殊的力学以及电学特性,有望应用于忆阻器中以提高器件的电学性能。在本文中,我们通过化学湿法刻蚀制备了Ti₃C₂粉末,通过旋涂工艺在忆阻器结构中引入Ti₃C₂薄膜。Ti₃C₂ MXene与SiO₂同时作为忆阻器阻变层,制备了Cu/Ti₃C₂/SiO₂/W结构的忆阻器,并且对其相关电学特性进行了探究。在该器件上,通过实验测得忆阻器典型的开关特性曲线并在双向直流电压下针对高、低阻态的可重复性、稳定性进行了实验。结果表明该器件能够在100个扫描循环过程中保持稳定的高、低阻态达到10⁴ s以上。同时,该器件状态能够受脉冲电压调节,实现突触间典型的双脉冲易化行为。实验结果表明基于Ti₃C₂ MXene的忆阻器将有望应用于构建新兴存储设备以及人工神经形态系统。     

Synthesis, characterization, and computational studies of 6-(RR'N)-nido-5,7-C2B8H11: a polyborane cluster with a cage-boron having an exopolyhedral dative boron-nitrogen double bond

The reactions of the arachno-4,6-C 2B 7H 13 carborane with the secondary and primary amines, Me 2NHBH 3 and ( t )BuNH 2BH 3, in ionic liquid media result in both boron-insertion into the cage at a position across the two cage-carbons and additional hydrogen-elimination via the reaction of a hydridic B-H with a protonic amine N-H hydrogen to produce the 6-(RR'N)- nido-5,7-C 2B 8H 11 carboranes. Computational characterizations of these compounds and the previously reported 6-ClC 6H 4-9-(RR'N)- nido-6-NB 9H 10 azaboranes indicate that the amine-nitrogens form unique exopolyhedral dative BN double bonds with a cage-boron.     

QUASI－FLOW CORNER THEORY ON LARGE PLASTIC DEFORMATION OF DUCTILE METALS AND ITS APPLICATIONS

ＱＵＡＳＩ－ＦＬＯＷＣＯＲＮＥＲＴＨＥＯＲＹＯＮＬＡＲＧＥＰＬＡＳＴＩＣＤＥＦＯＲＭＡＴＩＯＮＯＦＤＵＣＴＩＬＥＭＥＴＡＬＳＡＮＤＩＴＳＡＰＰＬＩＣＡＴＩＯＮＳＨｕＰｉｎｇ（胡平）ＬｉｕＹｕｑｉ（柳玉启）ＧｕｏＷｅｉ（郭威）ＴａｉＦｅｎｇ（台风）（Ｒ...     

Springback simulation and analysis of strong anisotropic sheet metals in U-channel bending process

The springback phenomenon of strong anisotropic sheet metals with U-channel bending as well as deep-drawing is numerically studied in detail by using Updating Lagrange FEM based on virtual work-rate principle, Kirchhoff shell element models and the Barlat-Lian planar anisotropic yield function. Simulation results are compared with a benchamark test. Very good agreement is obtained between numerical and test results. The focus of the present study is on the numerical simulation of the springback characteristics of the strong anisotropic sheet metals after unloading. The effects of the planar anisotropy coefficients and yield function exponent in the B-L yield function on the springback characteristics are discussed in detail. Some conclusions are given. The project supported by the National Natural Science Foundation of China (No. 19832020) and Provincial Natural Science Foundation of Jilin China (No.20000519)     

Fabrication of flexible AgNW/cellulose hybrid film with heat preservation and antibacterial properties for agriculture application

In the view of sustainable development and environmental protection, degradable agricultural films with on-demand thermal insulation properties have attracted growing research interest in the last few decades due to the deteriorating environment and extreme climate on the growth and existence of crops. Here, a general strategy has been developed to fabricate degradable silver nanowires modified cellulose (AgNW/cellulose) hybrid film with controllable thermal insulation and antibacterial properties by using plant cellulose and AgNWs as building blocks, PVA and PEG as film forming solvent, as well as their agriculture application. The results show that the AgNWs are evenly dispersed in the three-dimensional grid of cellulose, that they form a film that can withstand a certain tensile force and have good thermal stability. Due to the excellent electrical conductivity, the AgNW/cellulose hybrid films can provide excellent Joule heating, generating rapid thermal response and uniform electrical heating at a low supply voltage of 3 V. In the antibacterial tests against Escherichia coli and Staphylococcus aureus, the AgNW/cellulose hybrid films exhibited large diameters of inhibition zones, revealing the high antibacterial activity. Additionally, the AgNW/cellulose hybrid films showed highly stretchable behavior by delivering a breaking strain of 1.5% with a tensile stress of 0.45 MPa owing to the cross-linked structures of cellulose and AgNWs. Based on the above properties, this study not only provides a potential strategy for the fabrication of flexible and biodegradable agricultural films but also may provide new insights for agricultural thermal management.

     

溶质在动态改性氧化锆液相色谱柱上的保留行为

分别采用硬脂酸、环糊精和十二烷基磺酸钠动态改性自制的ZrO2微球,研究了流动相中甲醇和改性剂浓度对苯酚及苯甲酸的衍生物、苯胺衍生物及芳香烃类化合物的色谱保留行为的影响。中性及碱性化合物的保留时间较短,色谱峰对称;酸性化合物保留时间较长,色谱峰拖尾较严重。改性氧化锆表现出反相色谱性能。