Bioactive PKS–NRPS Alkaloids from the Plant-Derived Endophytic Fungus Xylaria arbuscula

A novel hybrid PKS–NRPS alkaloid, xylarialoid A (1), containing a 13-membered macrocyclic moiety and [5,5,6] fused tricarbocyclic rings, together with ten known cytochalasins (2–11), was isolated from a plant-derived endophytic fungus, Xylaria arbuscula. The chemical structures of all compounds were elucidated using 1D and 2D NMR, HR ESIMS spectroscopic analyses, and electronic circular dichroism (ECD) calculation. Compounds 1–3 and 10 exhibited significant antitumor activities against A549 and Hep G2 cell lines, with IC₅₀ values of 3.6–19.6 μM. In addition, compound 1 showed potent anti-inflammatory activity against LPS-induced nitric oxide (NO) production in macrophage RAW 264.7 cells (IC₅₀, 6.6 μM).     

新型吡唑肟衍生物的设计、合成与杀虫活性研究

为寻找高效与低毒的吡唑肟活性物质,设计合成了9个未见文献报道的新型吡唑肟化合物,通过¹H NMR、¹³C NMR及元素分析等方法确证了其目标物的结构。初步生物活性测试数据显示,在500µg/mL浓度下,目标化合物6a~6i对粘虫均有较好的杀虫效果,其杀死率均为100%,与对照药啶虫丙醚的防效相当,值得进一步深入研究。     

盐酸伊达比星杂质A的合成工艺优化及其高效液相分析

通过对盐酸伊达比星脱羟基杂质A的合成研究,为盐酸伊达比星的质控标准提供参考。以盐酸伊达比星为起始原料,经过4步反应得到脱羟基杂质A。本文提供了盐酸伊达比星杂质A的制备方法以及高效液相色谱分析方法,为杂质含量控制提供了依据。该工艺可以稳定、快速制备高纯度脱羟基杂质A,制备总收率为57.20%,纯度为57.20%,其结构经¹H NMR, ¹³C NMR和MS(ESI)表征。     

石蜡/膨胀石墨/石墨烯复合相变储热材料的制备及性能

以石蜡(PA)作为相变储热材料、 膨胀石墨(EG)作为主导热材料和支撑材料, 石墨烯气凝胶(GA)作为导热增强材料和辅支撑材料制备了PA/EG/GA复合相变材料, 研究了GA添加量对复合相变材料相变温度、 相变潜热、 导热性能以及循环稳定性的影响. 结果表明, 所制备的80%PA-17%EG-3%GA复合相变材料导热性能良好, 循环稳定性出色. 与80%PA-20%EG复合材料相比, 该材料的相变温度、 相变潜热以及循环稳定性无明显变化, 但导热系数由4.089 W/(m·K)提升到了5.336 W/(m·K), 显示出良好的应用前景.     

微波消解-石墨炉原子吸收光谱法分析测定食用菌中总砷

摘 要：采用微波消解-石墨炉原子吸收光谱法分析测定食用菌中总砷。取可食部分的食用菌粉碎均匀,采用微波消解对样品进行消解,将消解液于140℃赶酸至0.5mL ,用超纯水转移定容至25mL。以0.1%的硝酸钯为基体改进剂,塞曼扣背景,用石墨炉原子吸收光谱法测定总砷。方法检出限为0.4μg/L,线性范围为0~30 μg/L,线性相关系数(r)大于0.998,采用精密度考察方法重现性,不同浓度水平的RSD%均小于6.6%;三个浓度水平的加标回收率为80.6% ~ 103.9%,有证标准物质测定结果符合要求。实验结果表明,方法操作简便、灵敏、准确,适合食用菌中总砷的测定。对砷形态复杂的野生食用菌,微波消解后可直接采用石墨炉原子吸收光谱法测定总砷。     

超高效液相色谱–串联质谱法测定鲜蛋中氟苯尼考残留量的不确定度分析

评定超高效液相色谱–串联质谱法测定鲜蛋中氟苯尼考残留量的不确定度。建立测定鲜蛋中氟苯尼考的不确定度数学模型,不确定度来源包括标准溶液的质量浓度、样品溶液体积量取、称样质量、重复性,对不确定度分量分别进行评定,合成不确定值。鲜蛋中氟苯尼考残留量为1.49 μg/kg时,其扩展不确定度为0.19 μg/kg(k=2,P=95%)。为科学评价实验结果的准确性提供依据,为评定其它相关检测方法的不确定度提供参考。     

Electrospun polystyrene nanofibers as a novel adsorbent to transfer an organic phase from an aqueous phase

The aim of this work is to develop a simple phase‐transfer method for dispersive liquid–liquid microextraction. For this purpose, a polystyrene nanofiber was prepared by a facile electrospinning strategy and used for the first time as an adsorbent to transfer the organic phase in dispersive liquid–liquid microextraction procedure. The fiber was characterized and its chemical stability and excellent hydrophobicity enable it to selectively adsorb the organic solvent in an aqueous sample. High porosity and specific surface area provide a large adsorption capacity. Under the optimal conditions, the developed dispersive liquid–liquid microextraction with high‐performance liquid chromatography method was successfully applied to the analysis of aldehydes in environmental water samples. The merits of this approach are that it is easy‐to‐operate, low‐cost, time‐saving, and has satisfactory sensitivity. It provides an alternative way for fast and convenient phase transfer of the hydrophobic organic solvent from the aqueous phase.     

Quantitative and fingerprinting analysis of Atractylodes rhizome based on gas chromatography with flame ionization detection combined with chemometrics

This study assessed the feasibility of gas chromatography with flame ionization detection fingerprinting combined with chemometrics for quality analysis of Atractylodes rhizome. We extracted essential oils from 20 Atractylodes lancea and Atractylodes koreana samples by hydrodistillation. The variation in extraction yields (1.33–4.06%) suggested that contents of the essential oils differed between species. The volatile components (atractylon, atractydin, and atractylenolide I, II, and III) were quantified by gas chromatography with flame ionization detection and confirmed by gas chromatography with mass spectrometry, and the results demonstrated that the number and content of volatile components differed between A. lancea and A. koreana. We then calculated the relative peak areas of common components and similarities of samples by comparing the chromatograms of A. lancea and A. koreana extracts. Also, we employed several chemometric techniques, including similarity analysis, hierarchical clustering analysis, principal component analysis, and partial least‐squares discriminate analysis, to analyze the samples. Results were consistent across analytical methods and showed that samples could be separated according to species. Five volatile components in the essential oils were quantified to further validate the results of the multivariate statistical analysis. The method is simple, stable, accurate, and reproducible. Our results provide a foundation for quality control analysis of A. lancea and A. koreana.     

基于甲酸和氢氧化钠的衍生移动反应界面的数值计算与实验验证(英文)

在甲酸（α相）和氢氧化钠（γ相）缓冲液形成的移动反应界面的基础上,提出了一种衍生移动反应界面模型。模型表明在α相和γ相之间会形成一个新的β相,β相和α相形成衍生移动反应界面,β相和γ相形成移动界面。为了验证该模型的有效性,该文给出了相关理论及数值推导过程。此外,基于毛细管电泳和自制装置进行了相关实验。结果表明,若使用以前的移动反应界面,实验结果与理论计算存在较大误差,而采用该文提出的衍生移动反应界面,实验数据与理论计算结果高度一致。该文提出的衍生移动反应界面理论及模型对于电泳,特别是毛细管电泳中样品的分离与富集具有重要的意义。