Auswertung von Ge(Li)-Gammaspektren

Es wird eine automatische Auswertung von Ge(Li)-Gammaspektren mittels elektronischer Rechenmaschine vorgestellt. Sie besteht aus Peaksuche, Peakparameterbestimmung, Nuklididentifizierung sowie Aktivitāts- und Elementgehaltsbestimmung.     

Resolution Enhancement in SEA XLOC for Heteronuclear NMR Long-Range Correlation

It is shown how the resolution in SEA XLOC NMR spectra for distinguishing between heteronuclear two- and three-bond correlations for all ¹³C multiplicities can be improved by a modified experiment delivering absorptive profiles in the indirect dimension. The method is demonstrated with applications to ibuprofen and strychnine.     

两服务商竞争的研发外包知识转移信息披露决策

针对两服务商竞争的研发外包知识转移,考虑两个服务商知识吸收能力、信息获取能力均不同,且信息劣势方不知道信息优势方的知识吸收能力。通过建立以企业为领导者,两个服务商为跟随者的Stackelberg主从博弈模型,研究了企业和信息优势方的知识吸收能力披露决策,以及信息劣势方的信息处理决策,并用算例对结论加以说明。研究表明:仅当知识吸收能力较弱的服务商索取的单位报酬相对较低时,企业应披露信息优势方的知识吸收能力;仅当信息优势方知识吸收能力较弱时,其应披露自身知识吸收能力;信息劣势方应始终遵循信息优势方的信息披露策略;各方信息披露决策对企业和服务商均有不同影响。     

Identification of the absorptive constituents and their metabolites in vivo of Ziziphi Spinosae Semen by UPLC–ESI–Q-TOF–MS/MS

In this research, ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC–ESI–Q-TOF–MS/MS) was used for detection and identification of the absorptive constituents and their metabolites in rat plasma, urine and feces following oral administration of Ziziphi Spinosae Semen alcohol extract. After structure elucidation, a total of 12 compounds in rat plasma, comprising seven prototypes and five metabolites, 28 compounds in urine, comprising 17 prototypes and 11 metabolites, and 23 compounds in feces, comrpising 17 prototypes and six metabolites, have been tentatively identified by comparison with standard compounds and reference literature information. To the best of our knowledge, this is the first comprehensive and systematical metabolic study on the seed. Mostly importantly, we propose that gastric acid could convert jujubosides into an absorbable form of ebelin lactone oligosaccharides, which may be responsible for the low bioavailability and specific bioactivities of these compounds. Additionally, we deduced that the absorption site of ebelin lactone oligosaccharides is located in the stomach, and that the ebelin lactone form of jujubosides may be more suitable for absorption than its hydrolysis product. Our investigation will be helpful to narrow the scope for potentially active ingredients of the seed, and pave the way for determination of the pharmacological mechanism of the seed.     

Auswertung von Photopeaks auf linearem Untergrund

Es wird eine Methode der Peakauswertung in Kernstrahlungsspektren auf der Grundlage der optimalen Breite des Auswertebereichs beschrieben, die besonders für geringe Impulszahlen geeignet und sowohl bei der manuellen Spektrenauswertung als auch bei Verwendung der Spektrometerarithmelik vorteilhaft anwendbar ist.     

Dry‐cured ham tissue characterization by fast field cycling NMR relaxometry and quantitative magnetization transfer

Fast field cycling (FFC) and quantitative magnetization transfer (qMT) NMR methods are two powerful tools in NMR analysis of biological tissues. The qMT method is well established in biomedical NMR applications, while the FFC method is often used in investigations of molecular dynamics on which longitudinal NMR relaxation times of the investigated material critically depend. Despite their proven analytical potential, these two methods were rarely used in NMR studies of food, especially when combined together. In our study, we demonstrate the feasibility of a combined FFC/qMT‐NMR approach for the fast and nondestructive characterization of dry‐curing ham tissues differing by protein content. The characterization is based on quantifying the pure quadrupolar peak area (area under the quadrupolar contribution of dispersion curve obtained by FFC‐NMR) and the restricted magnetization pool size (obtained by qMT‐NMR). Both quantities correlate well with concentration of partially immobilized, nitrogen‐containing and proton magnetization exchanging muscle proteins. Therefore, these two quantities could serve as potential markers for dry‐curing process monitoring. Copyright © 2016 John Wiley & Sons, Ltd.     

五种染料的远红外光谱

衰减全反射模式的傅里叶变换红外光谱仪(ATR-FTIR)可以用来确定固体粉末样品的远红外光谱性质，并根据其指纹特征对未知物样品进行鉴定, 且具有快速、简便、灵敏、样品用量少等优点，已成为分析与表征染料的常用的手段。运用ATR-FTIR在真空条件下测试了汽巴蓝2B、去氧紫草素、靛蓝、靛红、硫靛红等五种染料在50~610 cm-1范围内的吸收光谱。实验结果表明这五种染料在此波段内均有明显的特征吸收峰并对其峰位进行了指认与描述。使用Gaussian09软件对硫靛红分子进行模拟计算与指纹谱指认，并根据可视化结果可以看出：硫靛红分子在50~610 cm-1范围内的特征吸收峰主要源于分子的集体振动，且其高频与低频的振动模式并不一致。模拟结果与实验结果相对符合较好，但仍然存在一定的差异：比如峰值位置的差异、吸收峰位的移动、模拟得到的新峰位等，主要是由于二者所基于的温度不同、理论计算没有考虑分子间的相互作用、ATR晶体与样品粉末的接触效果略差以及系统分辨率不够等因素导致的结果。     

Paper-based solid-state electrochemiluminescence sensor using poly(sodium 4-styrenesulfonate) functionalized graphene/nafion composite film

Herein, highly efficient solid-state ECL sensor was introduced for the first time onto the screen printed electrodes of the paper-based chips (PCs) based on the composite film of poly(sodium 4-styrenesulfonate) functionalized graphene (PSSG) and Nafion. Attributed to the cooperative characteristics of both PSS and graphene, PSSG ensured both effective Ru(bpy)₃²⁺ immobilization and fast electron transfer of Ru(bpy)₃²⁺ in the composite film. The ECL behaviors at the developed sensor were investigated using tripropylamine as a representative analyte and low detection limit (S N⁻¹ = 3) of 5.0 nM was obtained. It also exhibited more excellent reproducibility (relative standard deviations of 0.63% for continuous 45 cycles) and long-term stability (∼80% of its initial ECL intensity could be retained over 3 months). More importantly, assisted by the developed ECL sensor, discrimination of 1.0 nM single-nucleotide mismatch in human urine matrix could be realized on the PCs for the first attempt. Thus, the developed sensor was confirmed with the advantages of highly sensitivity, long-term stability, simplicity, low cost, disposability, high efficiency and potential applicability.     

Two‐dimensional strong cation exchange/positively charged reversed‐phase liquid chromatography for alkaloid analysis and purification

Peak tailing and nonalkaloid coelution usually hinder alkaloid purification. In this study, a 2DLC, strong cation exchange (SCX) coupled with positively charged RP (PGRP) LC, was developed to overcome these problems. Ten compounds including basic and nonbasic compounds were analyzed. Nonbasic compounds, which are coeluted with basic compounds on RP or PGRP columns, were weakly retained on the SCX column. In addition, a symmetrical peak shape (tailing factors <1.2) of basic compounds can be obtained in the current system. Compared to two other 2D systems, the current system provided the highest orthogonality (R² = 0.045). Furthermore, the SCX coupled with PGRP system was applied for alkaloid purification from a traditional Chinese medicine. Nineteen alkaloids were obtained and one of them was identified as a novel compound. The overall results demonstrate that the proposed system is a powerful tool for alkaloid purification.