Separation and quantitative determination of sesquiterpene lactones in Lindera aggregata (Wu‐yao) by ultra‐performance LC‐MS/MS

An ultra‐performance LC in combination with MS/MS method was established to evaluate the quality of Wu‐yao (the dried root of Lindera aggregata (Sims) Kosterm. (Lauraceae)) through simultaneous quantitation of five sesquiterpene lactones, linderagalactone D ( 1 ), linderagalactone C ( 2 ), hydroylindestenolide ( 3 ), neolinderalactone ( 4 ) and linderane ( 5 ). All compounds were separated on a Waters Acquity ultra‐performance LC HSS T3 column (2.1 mm×100 mm, 1.8 μm particle size) with linear gradient elution of acetonitrile and 0.1% formic acid. An ESI interface in the positive mode was employed prior to MS detection. All the compounds showed good linearity (R²≥0.9992). The recoveries, measured at three concentration levels, varied from 97.3 to 103.4% with RSDs <4.8%. The simple, rapid and reliable method was successfully applied to quantify the five components in 13 samples of Wu‐yao from different areas.     

适配体在癌症诊断与靶向治疗中的研究进展

核酸适配体是利用体外筛选技术,即指数富集的配体系统进化技术(SELEX),从核酸分子文库中得到的寡核苷酸片段。其与靶标物有很高的特异性和亲和力,将适配体作为识别单元的生物传感研究以及适配体偶联成像试剂的生物体内外成像研究在临床诊断中有很大的应用前景,此外,适配体靶向癌细胞或组织的治疗方法相比传统化学治疗副作用更小,在临床上也有极大的应用前景。本文综述了适配体目前在癌症诊断和靶向治疗两个方面的研究进展,并分析现阶段存在的问题以及面临的挑战。     

Single-walled carbon nanotubes as solid-phase microextraction adsorbent for the determination of low-level concentrations of butyltin compounds in seawater

Carbon nanotubes are a kind of new carbon-based nanomaterials, which have drawn great attention in many application fields. The potential of single-walled carbon nanotubes (SWCNTs) as solid-phase microextraction (SPME) adsorbent for the preconcentration of environmental pollutants has been investigated in recent years. In the present study, the feasibility of SWCNTs as SPME adsorbent for the determination of monobutyltin, dibutyltin and tributyltin in seawater samples was studied. To achieve this aim, the potential factors affecting the SPME efficiency, including extraction time, extraction temperature, desorption time, desorption temperature, and salinity were optimized. The developed method showed good performance according to the ICH (International Conference on Harmonization of Technical Requirements for Analytical Methods) criteria. The acquired calibration curves were linear (r ≥ 0.992) over the concentration range from ≤12 to 2000 ng L⁻¹. For all of the analytes, the limit of detection at signal-to-noise ratio of 3 was below 5 ng L⁻¹. Furthermore, in comparison with the commercial carboxen/polydimethylsiloxane fiber, the developed SWCNT fiber showed better thermal stability (over 350 °C) and longer life span (over 150 times). The application of the proposed method in environmental analyses was shown by analyzing seawater samples from the harbors on the Persian Gulf for butyltin residues. Some of the butyltins were detected in the analyzed samples. Results of the present study demonstrate the feasibility of the SWCNTs as SPME adsorbent for the determination of butyltins in seawater samples.     

利用维纳滤波改善声透镜光声成像系统的分辨率

为了克服衍射效应对光声成像系统分辨率的限制,需要采用逆卷积方法进行图像反演.从理论上分析了声透镜成像原理,模拟仿真了声透镜的点扩展函数对声透镜成像系统分辨率的影响和维纳滤波解卷积方法复原光声成像的过程,并利用自搭建的声透镜光声成像系统进行了深入的实验研究,得到了物平面上相距4 mm和3 mm的两个黑胶带点的直接成像光声...     

红外图像法鉴别打印机种类

采用红外图像系统对收集到的针式、激光、喷墨3种类型打印机的打印字迹样本各4份分别进行检验,依据3类打印机打印字迹的可见图像、化学图像和红外谱图,可以鉴别3种类型的打印机。可见图像鉴别可根据字迹的清晰程度及有无虚边等特点加以鉴别,化学图像鉴别可根据在不同的波程范围上化学图像清晰程度不同为依据。红外谱图部分主要是在相同的波程上吸收峰数目不同作为鉴别的主要依据。通过红外图像法鉴别打印机种类与其他方法相比,具有不破坏检材、检测范围广、检测速度快等优点。     

光声成像技术的最新进展

光声成像技术是生物医学领域中新兴的无损检测技术,具有对比度高、分辨率好、穿透能力强等优点.本文介绍了光声成像技术近年来的进展状况,主要涉及成像探测方式的改进、成像速度的加快、成像分辨率的提高以及图像重构算法的发展等.以该项技术在现代临床诊断中的应用为例,描述了其在生物医学领域中应用范围的拓宽.最后,总结了该项技术现存的...     

压力对可燃极限非单调作用的机理分析

采用CHEMKIN的PREMIX模块对非常压下贫燃侧的一维、层流CH4／Air预混火焰进行数值模拟,分析了不同的压力下辐射引起的最高火焰温度损失、主要反应的敏感性系数和主要自由基摩尔分数的变化。结果表明,辐射热损失随着当量比的下降而加强,在非单调变化的拐点附近,热辐射损失对最高火焰温度的相对变化作用明显加强。随着压力增...     

红外探测器成像实验研究

红外探测器广泛应用于多光谱成像系统中,文章提出并建立了一种红外线阵时间延迟积分探测器的成像实验系统,阐述了成像系统的工作原理,对影响成像质量的两个主要因素电子稳像与自动对焦进行了深入分析。利用高精度直流测速机确定了转台转速与探测器的行转移频率,采用卡尔曼滤波算法滤除了测速机带来的噪声,提高了速度匹配精度。在分析比较红外相机四种检焦方法的基础上采用视频信号幅度法进行检调焦。在国家光学机械产品质量监督检验测试中心实地搭建了成像实验系统,并分别对5.3,6.4和9.2mm宽度靶标成像。实验结果表明,采集到的原始靶标纹理清晰,照相分辨率达到了每毫米11.3对线,达到了实验预期目的。