CuCl_2/离子液体催化炔丙醇、仲胺与CO_2的三组分反应

以二氧化碳代替传统剧毒的光气等来合成氨基甲酸酯已成为研究的热点,然而现存的体系普遍需要高温高压等苛刻反应条件才能催化反应,并且很少有催化体系能够有效地回收和再利用.探索了将CuCl_2/离子液体(IL)用于炔丙醇、仲胺和CO_2的三组分反应合成β-羰基氨基甲酸酯.在常压、45℃的温和条件下,以较低催化当量(2%摩尔分数)的廉价易得的2价铜将多种类型的炔丙醇和仲胺通过简单的"一锅法"合成相应的目标化合物,并且循环利用3次后产率并未见明显下降.分步反应结合NMR监测的机理实验证明,炔丙醇与CO_2先生成的α-亚甲基环碳酸酯是反应的重要中间体,且醋酸型离子液体对炔丙醇和CO_2的活化具有重要作用.     

细胞表面壳化的研究进展

细胞表面壳化主要是通过物理、化学等技术方法对细胞表面进行修饰,形成完整均匀的有机、无机、金属纳米粒子或者复合壳层结构,从而使不能自身壳化的生物细胞表面形成保护壳甚至赋予细胞新的功能,使细胞具备多功能性。近年来,此技术在细胞存储、细胞运输、细胞传感器、细胞芯片以及细胞治疗等方面应用广泛,发展迅速。本文综合目前的研究现状,详细介绍了可进行细胞表面壳化的细胞类型、生物表面壳化的方法以及人造细胞外壳的工程技术在生物医学以及能源环境中的应用等。     

Controlled release of antibiotics from poly‐ε‐caprolactone/polyethylene glycol wound dressing fabricated by direct‐writing melt electrospinning

Wound dressing, which can release anti‐infectives in a controlled way, is taking an important role in the treatment and recovery of the open wound. An adequate release of antibiotics can prevent infections from microorganisms effectively. Among the new candidates of fabricating base materials for wound dressing, electrospinning fiber mats are attracting numerous attentions for their excellent performance in controlled drug delivery. The drug release behavior of electrospinning fiber mats can be tuned by changing the chemical components and the geometric structures of the mats. In this study, fiber mats with different geometric structures, which composed of poly‐ε‐caprolactone (PCL), polyethylene glycol (PEG), and ciprofloxacin (Cip) with different blending ratios, were successfully fabricated by direct‐writing melt electrospinning, and the release behavior of Cip were subsequently investigated in vitro. The results showed that the addition of PEG improved the hydrophilicity of the mats, which in turn affected the manner of drug release. The presence of PEG changed the releasing mechanism from a non‐Fickian diffusion into Fickian diffusion, which indicated that the diffusion of Cip from the composite fiber mats became the main factor of drug release instead of polymer degradation. Besides, with the same composition but different geometric structures, the drug release behavior is of significant difference. Therefore, all the Cip‐loaded composite fiber mats showed antibacterial activities but with different efficiency. In summary, the release of the drug could be controlled by adding PEG and changing the geometric structures according to the different requirement of wound dressings.     

A mussel‐inspired method to fabricate a novel reduced graphene oxide/Bi12O17Cl2 composites membrane for catalytic degradation and oil/water separation

In this study, a novel dopamine modified graphene‐based photocatalytic membrane with Bi₁₂O₁₇Cl₂ inserted was fabricated to modify the commercial cellulose acetate membrane via vacuum filtration method. Results showed the reduced graphene oxide (RGO)/poly(dopamine) (PDA)/Bi₁₂O₁₇Cl₂‐CA photocatalytic composite membrane exhibited 98% removal efficiency for methylene blue (MB) within 100 minutes and 96% removal efficiency for 4‐CP within 160 minutes. Importantly, the photocatalytic composite membrane can simultaneously achieve dye degradation and oil‐water separation in only one device within a short time. And the as‐prepared membrane displayed great antifouling performance and recyclability after 10 cycles. Meanwhile, the membrane showed excellent stability in the agitated water bath or different pH conditions. In summary, the photocatalytic membrane investigated in this study opens new avenue for treatment of wastewater.     

Characterization of foxing stains in early twentieth century photographic and paper materials

Abstract

The subject of this present work is a group of nine historical pictures shot in Palermo by the Sicilian photographer E. Interguglielmi in 1912. They are nine matte-collodion prints mounted on the original cardboard supports and all of them show foxing stains affecting the paper surface. In order to characterise the chemical composition of the supports and investigate foxing spots, non-destructive and micro-destructive analysis were carried out. X-rays fluorescence (XRF) analysis was used to characterise the elemental composition of all the mounting boards, allowing a comparison between the foxing spots and non-affected areas. Laser-Induced Breakdown Spectroscopy was used to investigate the presence of lower atomic number elements, not detectable by XRF, while SEM imaging allowed the investigation of surface appearance and nature of original paper samples from the cardboards.     

Application of microemulsions for the removal of synthetic resins from paintings on canvas

Abstract

Traditional cleaning methods with organic solvents often are not suitable for removal of aged resin so researchers have to find new formulations. In this work, a case study is reported in which new microemulsions were applied on the surface of a painting covered by some aged resin layers used during a previous restoration. Based on the quality of the intervention and the analysis of a sample of the varnish carried out with both MALDI-TOF and ATR-IR spectrometers, it was conjectured that this undesired material could be an acrylic polymer. So it was chosen to use xylene, ethyl acetate and propylene carbonate (XYL and EAPC) microemulsions (O/W oil in water). The first is able to solubilise only acrylic polymers, the second may solve both acrylic and vinyl resins. The first has had the greatest effect allowing complete varnish removal and original artwork restoration.     

Dissolvable layered double hydroxide as a sorbent in dispersive micro‐solid phase extraction for the determination of acidic quinolones in honey by HPLC

This study presents a simple and green dispersive micro‐solid phase extraction method for preconcentration of acidic quinolones from honey prior to high performance liquid chromatography determination. A two‐dimensional nanostructured zinc‐aluminum layered double hydroxide was synthesized and used as the sorbent for dispersive micro‐solid phase extraction. Its different characteristics from conventional sorbents is that it is dissolvable in acidic solution (pH < 4). After the extraction, the analyte elution step was omitted and thus the use of organic solvents was avoided. The key parameters influencing the extraction efficiency such as the amount of sorbent, pH of sample solution, vortex time, type and volume of acidic solution were investigated and optimized. The method exhibited low limits of detection (3.0?5.0 ng/g), good linearity (10?2000 ng/g) with coefficients of determinations higher than 0.9991, acceptable precision (RSD<9.1%) and accuracy (RE<5.8%). The proposed method is fast, efficient, eco‐friendly, and suitable for the determination of acidic quinolones in honey samples.