Performance comparison and parametric study on spiral groove gas film face seals

Several spiral groove gas film face seals (SGFS) with different layouts are compared quantitatively to analyze their merits and faults and application behaviors. In addition, a parametric study on downstream mode SGFS is conducted to determine its optimal parameters under certain working conditions. In the computation of gas film pressure on the face, finite element method (FEM) is applied to adapt to complicated geometrical boundary.     

HPLC determination and pharmacokinetics of osthole in rat plasma after oral administration of Fructus Cnidii extract

A simple and sensitive high-performance liquid chromatographic (HPLC) method is developed for the determination of osthole in rat plasma and applied to a pharmacokinetic study in rats after administration of Fructus Cnidii extract. After addition of fluocinonide as an internal standard, plasma samples are extracted with diethyl ether. HPLC analysis of the extracts is performed on a Hypersil ODS2 analytical column, using methanol-0.4% acetic acid (65:35, v/v) as the mobile phase. The UV detector is set at 322 nm. The standard curve is linear over the range 0.0520-5.20 microg/mL (r = 0.9979). The mean extraction recoveries of osthole at three concentrations were 81.0%, 91.2%, and 90.7%, respectively. The intra- and interday precisions have relative standard deviations from 1.9% to 4.9%. The limit of quantitation is 0.0520 microg/mL. The HPLC method developed can easily be applied to the determination and pharmacokinetic study of osthole in rat plasma after the animals are given the Fructus Cnidii extract. The plasma concentration of osthole from six rats showed a Cmax of 0.776 +/- 0.069 microg/mL at Tmax of 1.0 +/- 0.3 h.     

顺,反式环丙烷衍生物异构体的区分

在化学电离条件下，研究了４种顺、反式环丙烷衍生物与丙酮和醋酸乙烯酸乙烯酯的分子离子反应。异构体１，２的丙酮ＣＩ谱及其加合离子「Ｍ＋Ｈ＋Ａ」的ＣＩＤ谱都 可以区分该对异构体。化合物２，３和４可以和质子化丙酮及质子化二聚体发生加合反应，但化合物１仅能与质子化丙酮发生加合反应。在醋酸乙烯酯的ＣＩ谱中，观察到４个化合物的质子化二聚体，其中异构体１，２的质子化二聚体的ＣＩＤ谱也能反映它们立体结构的差异。     

A Recyclable bi‐functional Luminescent Zinc (II) metal–organic framework as highly selective and sensitive sensing probe for nitroaromatic explosives and Fe3+ ions

By introducing carboxyl tag to the aromatic ligands system and borrowing the organic template open framework idea, a stable fluorescent Zn metal–organic framework was successfully prepared through a rigid ligand H₆L (3,5‐bis‐(3‐carboxyphenoxy)benzoic acid) under hydrothermal conditions. The selectivity and sensitivity of the Zn‐MOF to metal ions and nitro‐aromatic compounds (NACs) were investigated by fluorescence quenching. And the Zn‐MOF showed a high sensibility of nitro‐aromatic compounds (NACs) and Fe³⁺ ions, especially for 4‐(4‐nitropheny lazo) resorcinol (NPLR). More importantly, the detection limit of the Zn‐MOF for detecting NPLR solution was found to be 1.71 ppb. Moreover, this sensor is remarkable recyclable and is promisingly applied for rapid, on‐site and sensing of explosive residuals.     

基于气相色谱-静电场轨道阱高分辨质谱的海参中风险物质的筛选北大核心CSCD

建立了一种基于改良QuEChERs的样品前处理新方法,并通过气相色谱-静电场轨道阱高分辨质谱(GC-Orbitrap HRMS)对海参样品中的有机氯农药类(OCPs)、多环芳烃类(PAHs)、酞酸酯类(PAEs)、多氯联苯类(PCBs)及其他农药类(ACs)等10大类289种具有健康风险的有机污染物进行了高通量高精准的定性鉴别和定量分析。通过将传统的QuEChERs方法与柱净化方法结合,提出了一种基于改良QuEChERs的简便生物样品制备新方法,经弗洛里硅土(Florisil)柱净化后脂含量降低了99.9%,显著减少了基质效应对分析结果的干扰,可在高分辨质谱(6万分辨率)全扫描模式下对289种目标化合物同时进行高精准定性筛查和定量分析。该方法定量限约0.56~57.8 pg/g,线性范围约6个数量级,回收率范围为40%~120%。由于Q Exactive GC-Orbitrap HRMS具备较高的质量分辨率和灵敏度,因此对目标化合物的定量限显著优于常规的色谱和质谱分析方法,常规方法无法检出的超痕量有机污染物利用该研究开发的方法可进行精准定量。基于此高覆盖度多目标分析方法对养殖场采集的海参样品进行分析,共从海参体内检出100种有机污染物,其中PAHs、ACs、PAEs、OCPs类检出总含量相对高于其他类污染物,总含量均值分别为157.8、153.2、64.4和46.4 ng/g dw。9-氯芴、5-氯苊、3-甲基胆蒽等多种新污染物首次在海参样品中检出,但含量都非常低。该方法简单高效,定量限低,线性范围宽,结果准确。此高覆盖度多目标分析方法可广泛应用于各种水产品中风险物质的广谱筛查和精准定量,为食品安全和绿色养殖提供技术支撑。     

Quantitative phase retrieval in X‐ray Zernike phase contrast microscopy

In recent years, increasing attention has been devoted to X‐ray phase contrast imaging, since it can provide high‐contrast images by using phase variations. Among the different existing techniques, Zernike phase contrast microscopy is one of the most popular phase‐sensitive techniques for investigating the fine structure of the sample at high spatial resolution. In X‐ray Zernike phase contrast microscopy, the image contrast is indeed a mixture of absorption and phase contrast. Therefore, this technique just provides qualitative information on the object, which makes the interpretation of the image difficult. In this contribution, an approach is proposed for quantitative phase retrieval in X‐ray Zernike phase contrast microscopy. By shifting the phase of the direct light by π/2 and 3π/2, two images of the same object are measured successively. The phase information of the object can then be quantitatively retrieved by a proper combination of the measured images. Numerical experiments were carried out and the results confirmed the feasibility of the proposed method. It is expected that the proposed method will find widespread applications in biology, materials science and so on.     

有机磷农药半抗原设计及多特异性抗体识别机制研究

基于抗原-抗体特异性识别、可同时检测多个对象的多残留免疫分析技术因具有简便、低成本、高通量等特点成为研究热点。作者前期以二乙氧基硫代磷酸酯类有机磷农药为对象,通过设计一系列半抗原,制备了有机磷农药多特异性抗体,并借助分子模拟、光谱分析、基因工程技术等手段从构效关系、弱相互作用及空间识别模型等方面研究了抗体识别机制,建立"半抗原-赖氨酸偶联物"模型用于研究半抗原与载体蛋白偶联后的空间构象及静电势能变化;提出"抗体与有机磷农药的识别与其最低空轨道能量和油水分配系数呈线性相关"的理论基础.本文对课题组近年来在该领域取得的研究成果进行了归纳总结,期望对指导小分子化合物半抗原的设计、多残留免疫分析方法的建立等提供借鉴.