A streptavidin functionalized graphene oxide/Au nanoparticles composite for the construction of sensitive chemiluminescent immunosensor

In this work, a novel streptavidin functionalized graphene oxide/Au nanoparticles (streptavidin/GO/AuNPs) composite is prepared and for the first time used to construct sensitive chemiluminescent immunosensor for the detection of tumor marker. The streptavidin/GO/AuNPs composite and the immunosensor are characterized using scanning electron microscopy, static water contact angle measurement and electrochemical impedance spectroscopy. The biofunctionalized composite has large reactive surface area and excellent biocompatibility, thus the capture antibody can be efficiently immobilized on its surface based on the highly selective recognition of streptavidin to biotinylated antibody. Using α-fetoprotein (AFP) as a model, the proposed chemiluminescent immunosensor shows a wide linear range from 0.001 to 0.1 ng mL⁻¹ with an extremely low detection limit down to 0.61 pg mL⁻¹. The resulting AFP immunosensor shows high detection sensitivity, fast assay speed, acceptable detection and fabrication reproducibility, good specificity and stability. The assay results of serum samples with the proposed method are in an acceptable agreement with the reference values. This work provides a promising biofunctionalized nanostructure for sensitive biosensing applications.     

Direct analysis in real time mass spectrometry and multivariate data analysis: A novel approach to rapid identification of analytical markers for quality control of traditional Chinese medicine preparation

The paper presents a novel strategy to identify analytical markers of traditional Chinese medicine preparation (TCMP) rapidly via direct analysis in real time mass spectrometry (DART-MS). A commonly used TCMP, Danshen injection, was employed as a model. The optimal analysis conditions were achieved by measuring the contribution of various experimental parameters to the mass spectra. Salvianolic acids and saccharides were simultaneously determined within a single 1-min DART-MS run. Furthermore, spectra of Danshen injections supplied by five manufacturers were processed with principal component analysis (PCA). Obvious clustering was observed in the PCA score plot, and candidate markers were recognized from the contribution plots of PCA. The suitability of potential markers was then confirmed by contrasting with the results of traditional analysis methods. Using this strategy, fructose, glucose, sucrose, protocatechuic aldehyde and salvianolic acid A were rapidly identified as the markers of Danshen injections. The combination of DART-MS with PCA provides a reliable approach to the identification of analytical markers for quality control of TCMP.     

Determination of Volatile Markers from Magnum Hops in Beer by In-Tube Extraction—Gas Chromatography—Mass Spectrometry

ABSTRACT

A chromatographic method was developed for the identification of volatile markers from Magnum hops in two types of beer. The study was initially performed with Magnum hop pellets and hop essential oil and subsequently with traditional and flavored beer during the primary fermentation. The volatile compounds were isolated employing the in-tube extraction (ITEX) technique followed by identification and quantification through gas-chromatography—mass spectrometry (GC-MS) operating in scan mode. The main authentication markers identified in traditional beer were from aromatic compounds, aldehydes and alcohol esters. The most predominant authentication marker compounds in beer flavored with Magnum hop essential oil were obtained from terpenoids, followed by acid esters, alcohol esters and alcohol classes. A unique feature of this study was represented by the discriminant markers for the authentication of Magnum hop variety, identified in hop pellets, hop essential oil and flavored beer. The application of this methodology can be used for optimization of brewing technology and process parameters in view of prolonging fruity hop flavor stability of Romanian beers.     

On the Deformation of the Circumflex Coronary Artery During Inflation Tests at Constant Length

Here we investigate whether the deformation observed in an experiment in which the porcine circumflex coronary artery is subjected to inflation at constant length included in the class, , , . We find that this is not the case and discuss its implications in the study of the mechanics of this artery. Moreover, we identify and quantify the uncertainty in the value of the invariants of the left Cauchy–Green tensor inferred from the 2D motion of markers affixed to the surface of the test specimen, and suggest that 3D tracking of markers is needed due to inherent bending and twisting induced by pressurization in vitro.     

Investigation of genetic variants of α-1 acid glycoprotein by ultra-performance liquid chromatography–mass spectrometry

Genetic variants of human plasma alpha-1 acid glycoprotein (AGP) have been studied in cancer, compared with a group of healthy control. AGP has four genetic variants: AGP F1, F2, and S variants correspond to the ORM1 gene whereas AGP A corresponds to the ORM2 gene. The proportion of ORM1 and ORM2 variants were studied in plasma using a novel UPLC–MS method. Plasma total AGP level was 0.5 ± 0.2 g L⁻¹ and the proportions of the ORM1 and ORM2 variants were 76.3 ± 8.2% and 23.7 ± 8.2%, respectively. In cancer plasma AGP levels increased fourfold and the proportion of ORM1 variants increased to 88.7 ± 6.8%. Changes in the proportion of genetic variants due to cancer were clearly significant, as shown by statistical analysis. Three different cancer types have been studied, lymphoma, melanoma, and ovarian cancer. The results did not show any difference depending on cancer type. The results indicate that, in accordance with prior expectations, the ORM1 variant is predominantly responsible for the acute-phase property of AGP.     

依据RAPD片段克隆而建立的团头鲂PCR鉴定法

通过对团头鲂RAPD片段的克隆、Southern杂交筛选和DNA序列分析,设计出3对PCR引物：M1F／M1R、M3F／M3R和M5F／M5R,这3对引物分别扩增出约1．00、1．15、0．56kb的DNA主带;HaeⅢ能将前两个片段酶民两个几乎相等或相似的小片段。经部分团头鲂群体和其它12种鱼DNAPCR验,除三角鲂外,这3对引物具有很强的团头鲂特羿性,重复性100％,可以用于除三角钫以外的团头鲂的分子标记或分子鉴定。     

气相色谱法用于分枝杆菌脂肪酸组成与菌种鉴定的研究

采用非极性毛细管柱气相色谱法对３株分枝杆菌细胞脂肪酸化学组成进行了研究,得到特异性指纹识别图,并对７例临床分离的分枝杆菌进行了鉴别。结果表明,结核菌硬脂酸（ＴＳＡ）为分枝杆菌属的特征组分,其含量与其他中长链脂肪酸的百分组成随菌种不同而异。     

An experimental and numerical investigation of container filling with viscous liquids

This work is concerned with a study of container filling, with particular reference to the food industry. A computer code was developed and an experimental rig was built, the main purpose being to validate the software. The computational fluid dynamic (CFD) code, called GENSMAC, was specifically designed for relatively slow viscous flow and was capable of capturing multiple free surfaces. This paper focuses on the design of the experimental rig and how it functions. The visual output of the code is then compared with high‐speed photographic shots of glucose syrup being jetted into a tub for a selected number of flow regimes. Copyright © 1999 John Wiley & Sons, Ltd.     

The surface marker and micro cell method

A new method is presented for the simulation of two-dimensional, incompressible, free surface fluid flow problems. The surface marker and micro cell (SMMC) method is capable of simulating transient free surface fluid flow problems that include multivalued free surfaces, impact of free surfaces with solid obstacles and converging fluid fronts (including wave breaking). New approaches are presented for the advection of the free surface, the calculation of the tentative velocity, final velocity and pressure fields and the use of multivalued velocities to treat converging fluid fronts. Simulation results are compared with experimental results for water sloshing in a tank to demonstrate the validity of the new method. Convergence of the new method is demonstrated by a grid refinement study. © 1997 John Wiley & Sons, Ltd.     

不同年份老香黄定量分析及其化学模式识别研究

建立了一种联合化学标志物定量分析和化学模式识别技术快速判别不同年份老香黄的方法,并筛选其差异性化学标志物.采用超高效液相色谱-串联质谱(UPLC-MS/MS)建立了对21种与老香黄相关的化学标志物及其内标物山柰酚-3-O-芸香糖苷的检测方法,该方法的线性关系良好,灵敏度高,专属性强,可用于对不同年份老香黄的区别分析.根...