E,E-1,4-二[2′,2″-(苯并噁唑基乙烯基)]苯及其衍生物的合成和光性能研究

合成了E,E-1,4-二[2′,2″-(苯并(口恶)唑基乙烯基)]苯及衍生物共14种,测定了它们的熔点、红外光谱、核磁共振氢谱、紫外吸收光谱和荧光发射光谱、荧光量子产率及激光性能。     

催化动力学光度法测定痕量钴

研究了以镁试剂Ⅰ作指示物,Co(Ⅱ)催化过氧化氢氧化镁试剂Ⅰ褪色反应的动力学条件,据此提出催化光度法测定痕量钴的新方法.方法的灵敏度为 1.15×10~(-11)g·ml~(-1),测定范围0.06～0.25μg/25ml,用于酒类中钴含量的测定,结果良好.     

Synthesis and rheological investigation of self‐healable deferoxamine grafted alginate hydrogel

Deferoxamine grafted alginate (SA‐DFA) was successfully synthesized via amidation of sodium alginate with deferoxamine mesylate as determined by H‐NMR and elemental analysis. SA‐DFA with different graft yield was obtained by adjusting the ratio of sodium alginate and deferoxamine mesylate. It was found that aqueous solution of SA‐DFA could form hydrogel spontaneously due to hydrogen bonding interactions, which also endowed the SA‐DFA hydrogel with self‐healing capability. The healing efficiency of SA‐DFA hydrogels ranged from 53.64 to 90.16%. In addition, surface morphologies of SA‐DFA hydrogels before/after self‐healing process were demonstrated by SEM images. We anticipated that such self‐healable alginate hydrogel would be applied in the field of wound healing. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 856–865     

Upgrading Pectin Production from Apple Pomace by Acetic Acid Extraction

Applied Biochemistry and Biotechnology - Pectin, as one of the most widely used functional polysaccharide, can be abundantly extracted from apple pomace which is the main by-product of apple juice...     

The effects of chemical composition and distribution on the preservation of phytolith morphology

Different types of phytolith even when coming from the same plant react to high temperatures in different ways. To understand the behavior of phytoliths upon heating, we examined composition and distribution of some elements within different phytolith types using SEM-EDS and synchrotron radiation μ-X-ray fluorescence. By analyzing phytoliths from rice husk, rice leaf and Than tree leaf, we find that the compositions and distributions of metal oxides within different phytolith types are quite different. It is well known that metal oxides have been used as fluxing agent to reduce the melting temperature of SiO₂ in the production of glass, and different metal oxides can be used to produce a variety of glass with diverse features. Similarly, metal elements including potassium, magnesium and calcium in phytoliths should also act as a fluxing agent under high temperature, and the differential compositions and distributions of these metal elements within the phytoliths resulted in the variable reaction to heating. In sum, there is a negative relationship between the flux elements composition in phytoliths, and the temperatures at which phytoliths deform; furthermore, potassium and calcium in the rice leaf phytolith are almost evenly distributed in all parts, which may cause the phytolith’s shape to deform evenly. In comparison, Than tree leaf phytolith is found to have a high percentage of potassium and calcium located exclusively on the outside, which may explain why the deformation of Than tree leaf phytolith occurs firstly at the outside.     

Hierarchical FeCo2S4@FeNi2S4 Core/Shell Nanostructures on Ni Foam for High-Performance Supercapacitors

The design of electrode materials with rational core/shell structures is promising for improving the electrochemical properties of supercapacitors. Hence, hierarchical FeCo₂S₄@FeNi₂S₄ core/shell nanostructures on Ni foam were fabricated by a simple hydrothermal method. Owing to their structure and synergistic effect, they deliver an excellent specific capacitance of 2393 F g⁻¹ at 1 A g⁻¹ and long cycle lifespan as positive electrode materials. An asymmetric supercapacitor device with FeCo₂S₄@FeNi₂S₄ as positive electrode and graphene as negative electrode exhibited a specific capacitance of 133.2 F g⁻¹ at 1 A g⁻¹ and a high energy density of 47.37 W h kg⁻¹ at a power density of 800 W kg⁻¹. Moreover, the device showed remarkable cycling stability with 87.0 % specific-capacitance retention after 5000 cycles at 2 A g⁻¹. These results demonstrate that the hierarchical FeCo₂S₄@FeNi₂S₄ core/shell structures have great potential in the field of electrochemical energy storage.     

Fe2O3-catalyzed Pummerer rearrangement of acyl chlorides and sulfoxides: Facile synthesis of alkylthiomethyl ester

A simple, effective approach for the Pummerer rearrangement of acyl chlorides with sulfoxides by using a low-cost and more abundant Fe catalyst has been described. The alkylthiomethyl ester products were prepared in good to excellent yields for a range of different substrates including asymmetrical sulfoxides and acyl chlorides with a variety of functional groups under mild reaction conditions. The reaction features short reaction time, simple manipulation, cheap reagents and a broad substrate scope. Single crystal X-ray analysis of a representative methylthiomethyl (MTM) group containing product was also reported.     

Synthesis and characterization of A2 + B3 type hyperbranched aromatic-aliphatic polyester with carboxyl end groups

New types of carboxyl-terminated hyperbranched polyesters (HBPEs) with aromatic-aliphatic structure were synthesized by single step-melt polycondensation of adipic acid (as A2 monomer) and phloroglucinol (as B3 monomer) as a core via A₂ + B₃ approach, at three different monomer mole ratios (A₂/B₃ = 1: 1, 1.5: 1, 2: 1, respectively). FTIR spectroscopy indicated that the polymers contained hydroxyl groups, ester bonds, benzene ring, methyl and methylene groups, which were in agreement with the expected HBPEs. The HBPEs have inherent viscosities about 0.24 to 0.27 dL/g. The degree of branching of the HBPEs was estimated to be 0.45–0.49% by ¹H-NMR and ¹³C-NMR measurements. The melting temperature of HBPE-1, HBPE-2 and HBPE-3 were 154, 155 and 160°C respectively measured by differential scanning calorimetry (DSC). The synthesized polymers were thermally stable; the thermogravimetric analysis (TGA) measurement revealed that HBPEs had 10% weight loss at 310°C in nitrogen.     

Rutin and Quercetin Decrease Cholesterol in HepG2 Cells but Not Plasma Cholesterol in Hamsters by Oral Administration

Rutin (R) and quercetin (Q) are two widespread dietary flavonoids. Previous studies regarding the plasma cholesterol-lowering activity of R and Q generated inconsistent results. The present study was therefore carried out to investigate the effects of R and Q on cholesterol metabolism in both HepG2 cells and hypercholesterolemia hamsters. Results from HepG2 cell experiments demonstrate that both R and Q decreased cholesterol at doses of 5 and 10 µM. R and Q up-regulated both the mRNA and protein expression of sterol regulatory element binding protein 2 (SREBP2), low-density lipoprotein receptor (LDLR), and liver X receptor alpha (LXRα). The immunofluorescence study revealed that R and Q increased the LDLR expression, while only Q improved LDL-C uptake in HepG2 cells. Results from hypercholesterolemia hamsters fed diets containing R (5.5 g/kg diet) and Q (2.5 g/kg diet) for 8 weeks demonstrate that both R and Q had no effect on plasma total cholesterol. In the liver, only Q reduced cholesterol significantly. The discrepancy between the in vitro and in vivo studies was probably due to a poor bioavailability of flavonoids in the intestine. It was therefore concluded that R and Q were effective in reducing cholesterol in HepG2 cells in vitro, whereas in vivo, the oral administration of the two flavonoids had little effect on plasma cholesterol in hamsters.