A Novel Method of Analytical Transmission Electron Microscopy for Measuring Highly Accurately Segregation to Special Grain Boundaries or Planar Interfaces

A new technique of analytical transmission electron microscopy has been developed for determining accurately the amount of solute atoms incorporated into well-defined planar defects in solids, such as stacking faults, special grain boundaries or interfaces. The method is based on recording series of analytical spectra taken with different electron beam diameters on the same position centred above a defect that is oriented nearly edge-on. The matrix/solute ratio is then plotted as a function of the electron beam radius, linear regression is performed and the segregation level is determined from the slope of the best fit. This method can be applied to energy-dispersive X-ray (EDX) or electron energy-loss spectroscopy (EELS) in a transmission electron microscope. It necessitates a nano-probe mode but no scan unit. Reliability and accuracy have been tested numerically. Simulations suggest an accuracy in the determination of the Gibbsian solute excess at a special grain boundary down to ±0.1 atoms nm⁻² under typical experimental conditions, with a maximum error about twice as large.     

Archaeolithoporella and Tubiphytes : Affinties and Paleoecology in Permian Reefs of South China

Archaeolithoporella is one of the most important Permian reef-building organisms, but itsaffinity has long been controversial. It was first reported in Japan and was considered as a coralline red alga. Since then it has been recognized in Permian reefs in other parts of the world. Many researchers have studied the materials they had found and the Japanese holotype specimen. Most have concluded that it is a problematic alga. or just a problematica because of weak criteria for definition. Some have even considered it inorganic. However, relict cellular structures and microtubular laminae found in well-preserved specimens from Permian reefs in South China strongly support a coralline red algal affinity for the genus.In situ preserved Archaeolithoporella is restricted within the typical framework facies and it occurs most abundantly in syndepositionally cemented framestones. This suggests that Archaeolithoporella required a firm substrate and clear but agitated sea water. Archaeolithoporella is often found     

萜类化合物的QSRR研究及其在结构鉴定中的应用

采用顶空固相微萃取(SPME)-气相色谱质谱(GC-MS)联用技术分析石香薷和腊梅鲜花中的萜类化合物, 通过保留指数与质谱解析相结合, 分别对化合物进行结构鉴定, 共鉴定出17种单萜化合物, 30种倍半萜化合物. 采用遗传算法(GFA)分别对单萜及倍半萜化合物建立定量结构-色谱保留关系(QSRR)预测模型, 并对该模型进行显著性及预测能力的检测. 同时, 利用计算所得到的模型分别对随机选取的几个萜类化合物进行保留指数预测. 结果表明: 计算保留指数与预测保留指数接近, 模型预测性能较好. 该研究为各种单萜化合物及倍半萜化合物保留指数的预测提供了一种有效手段, 同时, 为建立有效的GC-MS定性方法提供了一定的依据.     

A Spectro-Microscopic Approach for Thin Film Analysis: Grain Boundaries in mc-Si and Sn/SnO2 Nano Particles

 Synchrotron radiation based spectro-microscopy is shown to be an exciting tool for elemental analysis in the field of heterogeneous interfaces, thin films, and device technology. Results are reported, taken with a spectrometer that enables the combination of a photoemission electron microscope (PEEM) with photoelectron spectroscopies (XPS, UPS) operated at a high brilliance undulator beam line at BESSY. The properties of mc-Si (multi crystalline silicon) are of interest because of their applications in low priced photovoltaic devices. An example of how to analyze the surface potentials of such surfaces without removing the native oxide is given. Tin nano-scale particles are shown to be the decisive factor affecting the corrosion prevention of passivated tinplate surfaces.     

A Quantitative Spectrometric Assay for the Determination of Solution Concentration of para-sulphonato-calix[n]arenes and Their Derivatives

A spectrometric assay for the determination of concentration of para-sulphonato-calix[n]arenes and their derivatives has been developed using dimethylmethylene blue (DMMB) as a probe. Interaction with para-sulphonato-calix[n]arenes leads to a metachromatic shift in the spectrum of DMMB with appearance of a peak at 536 nm and diminution of the spectral intensity of the peaks at 594 and 649 nm. The method shows good linearity in the concentration range 0–6 μg/ml for para-sulphonato-calix[n]arenes. in final form: 27 December 2004     

荧光钙探针试剂及其在生物分析中的应用

本文评论了荧光钙探针试剂合成、性质、结构和生物分析应用方面的进展。各种典型的荧光钙探针试剂均已分别加以讨论。     

A DFT Study on Intramolecular Hydrogen Bond in Substituted Catechols and Their Radicals

Density functional theory(DFT)at B3LYP/6-31G(d,p) level was employed to calculate intramolecular hydrogen bond enthalpies (H1HB),O-H charge differencces,O-H bond lengths and bond orders for various substituted catechols and their radicals generated after H-abstraction.It was found that although the charge difference between hydrogen-bonded H and O played a role in determining H1HB,H1HB was mainly governed by the hydrogen bond length.As the oxygen-centedred radiocal has great tendency to form a chemical bond with the H atom,hydrogen bond lengths in catechloic radicals are systematically shorter than those in catechlos,hence,the H1HB for the former are higher than those for the latter.     

A Routine Method for the Quantitative Determination of Polycyclic Aromatic Hydrocarbons (PAHs) in Urban Air

Abstract

We have developed a method for the quantitative determination of polycyclic aromatic hydrocarbons (PAHs) present in urban air, which can be performed rather quickly, and which uses a minimal amount of solvents.

Air samples were collected using a home-made low-volume air sampler equipped with glass fibre filter and polyurethane foam plugs. After Soxhlet extraction a liquid-liquid partition was carried out to isolate the PAH fraction. This liquid-liquid partition was performed in micro-scale, enabling us to use small quantities of the solvents and to separate the solution layers very rapidly using a centrifuge. Sample clean-up was accomplished on a high performance liquid chromatograph equipped with two normal phase silica columns. The losses of all investigated PAHs occurring during the various steps of sample clean-up have been determined. The qualitative and quantitative determination of the PAHs was carried out by capillary gas chromatography; the results were confirmed by GC/MS measurements.

The analytical procedure described was applied over a period of one year to measure the concentrations of 21 PAHs in the city of Vienna at a site with high traffic density. The concentrations of the four more volatile PAHs were determined on a semi-quantitative basis. The ratio of two selected PAHs was used to estimate the respective contribution of traffic and domestic heating to the total PAH level at the sampling site.     

Comparison of GC and HPLC Methods for Quantitative Analysis of Tinuvin 622 After Saponification in Polyethylene

This study describes the sample preparation and two chromatographic techniques for determination of Tinuvin 622 in polyethylene. The first part of the two methods consisting of dissolving the polyethylene in boiling xylene is followed by addition of a methanolic solution of potassium hydroxide. The polymeric light stabilizer, Tinuvin 622, is thereby saponified to 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol (diol). Addition of the methanolic solution of the saponification reagent simultaneously precipitates the polyethylene matrix. Then the diol is quantified using either gas chromatography (GC) or high performance liquid chromatography (HPLC). For GC, a Macherey Nagel Optima-17 capillary column (30m×0.25mm ID, film thickness 0.25µm) is used. Nitrogen is used as carrier gas and make-up gas. The detection system is a flame ionization detector. For HPLC, an octadecyl silane (ODS) column (30cm×4mm, particle size 5µm) and a mobile phase methanol: water mixture (3:97, v/v) are used. Detection of analyte is carried out at 215nm. Both methods can be used to determine Tinuvin 622 in polyethylene in the concentration range of 0.02–1%, which represents the usual application concentration.     

哥纳三醇类似物抗A2780肿瘤细胞活性及三维定量构效关系研究

以合成的54个哥纳三醇类似物为研究对象, 测试了其体外抑制肿瘤A2780细胞株的活性, 对其中的37个化合物用比较分子力场(CoMFA)研究了哥纳三醇类似物结构与抑制A2780肿瘤细胞活性的三维定量构效关系, 提出了对哥纳香醇甲结构改造的方法, 对寻找更好活性的化合物有重要的指导意义     

两种基于RAJI细胞的抗CD20单抗新型定量方法的比较及在药物代谢动力学中的应用

建立和比较基于RAJI细胞的流式细胞法(Flow cytometry assay,FCA)和细胞放射免疫法(Immuno-radiametric assay,IRA)测定重组抗CD20人源化单克隆抗体(r-anti-CD20zumAb)的浓度.两种方法均利用标记后抗体和被检测抗体竞争性结合RAJI细胞表面的CD20抗原,由标记后抗体的荧光或放射性变化而间接反应检测抗体的浓度.FCA和IRA定量范围分别为0.1～100 mg/L和0.04～20 mg/L,FCA的日内及日间精密度分别小于4.0%和3.0%,准确度为-1.7%～1.1%,IRA的日内及日间精密度值均小于7.0%,准确度为-8.9%～13.2%.方法学确证研究表明,两种方法均具有良好的特异性、灵敏度、精密度和准确度.血浆样品分析结果显示,两种方法具有良好的一致性,是检测猕猴血浆中人源化单克隆抗体浓度的理想方法.     

新型冠状病毒小分子药物的临床效果及其合成方法概述

冠状病毒是一类广泛存在且对人及家畜具有严重危害的病原体,具有较高的传播性及致死率。2019年末爆发的新型冠状病毒（SARS-CoV-2）所引发的全球疫情持续至今,累计感染人数已经超过三亿,并造成了五百多万的死亡病例。随着病毒不断变异,造成疫苗的防护效率不断下降,时刻威胁着人们的健康安全,因此针对新型冠状病毒的小分子药物的开发就显得尤为必要。本文针对一些重要的新型冠状病毒的小分子药物进行概述,介绍了它们的作用靶点、合成情况、治疗效果以及所处的开发阶段,以期为抗新冠病毒药物的研发和临床研究提供一些参考。     

HPLC and GC Methods for Determination of Lubricants and Their Evaluation in Analysis of Real Samples of Polyethylene

High performance liquid chromatography (HPLC) and gas chromatography (GC) are introduced for analysis of polymer lubricants (stearamide, oleamide and erucamide). In the HPLC method, a reverse phase octadecylsilane (ODS) column along with acetonitrile/methanol (60:40) as a mobile phase were used. Detection of analytes was performed by a UV detector at 202 nm. The analysis time was less than 8 min. In the GC method, polar capillary column and flame ionization detector (FID) were used for separations and detection, respectively. The analysis time by GC was longer than HPLC and was about 30 min. Limits of detection, linear range and repeatability of both methods are similar, but determination of oleamide in real samples by HPLC method is difficult due to complexity of the initial part of HPLC chromatogram in polyethylene samples. That problem is not observed in the GC method. Detection limits in both methods for all analytes are lower than 0.003% which are much lower than the amount of lubricants in commercial polymers (0.05–0.2%).     

Region-Specific Biomarkers and Their Mechanisms in the Treatment of Lung Adenocarcinoma: A Study of Panax quinquefolius from Wendeng,China

Panax quinquefolius, a popular medicinal herb, has been cultivated in China for many years. In this work, the region-specific profiles of metabolites in P. quinquefolius from Wendeng was investigated using liquid-chromatography–quadrupole–time-of-flight-(LC–Q–TOF)-based metabolomics analysis. The three most abundant biomarkers, identified as ginsenoside Rb₃, notoginsenoside R₁, and ginsenoside Rc, were the representative chemical components employed in the network pharmacology analysis. In addition, molecular docking and western blotting analyses revealed that the three compounds were effective binding ligands with Hsp90α, resulting in the inactivation of SRC and PI3K kinase, which eventually led to the inactivation of the Akt and ERK pathways and lung cancer suppression. The outcomes obtained herein demonstrated the intriguing chemical characteristics and potential functional activities of P. quinquefolius from Wendeng.     

The Fossils in Shangxi Group and Its Implication for Tectonics, Southern Anhui, China

The Shangxi Group is the local name in southern Anhui Province and it is believed to be the equivalence of the well-known Banxi Group in Hunan Province, southern China. So the area occupied by the Shangxi Group was regarded as a part of the "Jiangnan old land" of Presinian till it was challenged by the present authors years ago. After we postulated that there may be some strata of Palaeozoic Era in Shangxi Group, some microfossils and then macrofossils of Palaeozoic were found in some part of it. The macrof os-sils, Lingula sp. , Conulariid and the microfossils indicate that most units of the Shangxi Group are Palaeozoic strata. Based on the discovery of these fossils and the recognition of the tectonic-setting of the different tectono-petrologic units in the Shangxi Group, three different stratigraphic sequences (island-arc volcanics, back-arc sediments and the cover of passive margin of Yangtze Continental Plate) are established and the tectonic evolution of them is postulated in the present paper. Al     

A Numerical Simulation of the Winter-Time Current System in the China Sea and Adjacent Areas

The monthly mean circulations in the whole Pacific Ocean are investigated numerically by using a barotropic ocean model with finer horizontal resolutions. The current system in the China Sea and its adjacent areas has been well reproduced. Especially, some warm currents moving windward in winter, such as the South China Sea Warm Current (SCSWC), Taiwan Warm Current (TWO, Yellow Sea Warm Current (YSWC) and Tsushima Warm Current (TsWC) are simulated very well. Numerical results of January show that there exists indeed a so-called "Taiwan-Tsushima-Tsugaru Warm Current System" (TTTWCS) which originates from the area off the southeastern Hainan Island and enters the Pacific Ocean mainly through the Tsugaru Strait in January.     

一种新多肽表征方法及支持向量机用于肽HPLC定量结构-保留建模预测

从20种天然氨基酸的1369种性质参数经主成分分析得出一种新多肽序列表征方法——SZOTT. 将其用于71个不同长度肽序列表征, 以偏最小二乘(PLS)和支持向量机(SVM)建立定量结构-保留模型(QSRM). 研究表明, SZOTT能够较好表征71个肽序列特征, 其含信息量大且易操作, 与PLS相比, SVM对lgk建模预测表现出较强的拟合能力和良好外部预测能力, SZOTT表征方法和SVM建模可进一步用于肽HPLC保留行为研究.     

测定微量血清铜、锌的新方法

报道了单用重蒸馏氏倍稀释微量血清后,直接采用ＰＥ４００型原子吸收仪,ＨＧＡ７００型石墨炉,测定血清中铜,锌浓度的新方法。本法用血量少,只用重蒸馏水稀释,标本不易受污染,测定结果稳定,与标准的火焰原子吸收法测定结果有很好的相关性。本法可提高微量法测定铜,锌浓度的准确性,有助于末梢血微量元素测定方法在临床的推广,尤其适用于儿科病儿及需反复测定多种元素的病人。     

Quantitative Determination by Using HPLC and GLC Methods for Cocaine HCl in Synthetic Binary Mixtures with Procaine HCl,Lidocaine HCl and Caffeine

ABSTRACT

Cocaine HCl is a substance which creates psychological and physical dependence. Usually it is available on the market being diluted by other substances, like local anesthetics, analeptics and CNS stimulating agents and inert substance.

In this study, HPLC and GLC methods were applied for qualitative and quantitative determinations of synthetic binary mixtures. In the HPLC determination, μ Bondopack C₁₈ 10 μm. column system, a mobile phase consisting of methanol-water-phosphoric acid-1% hexylamine (75:175:250:3,5) and U.V. detection by photodiodearray (196–600 nm) were used.

The linear concentration areas were found in a range of 2.5–25 μg/mL. The R.S.D percentages for cocaine HCl, procaine HCl, lidocaine HCl and caffeine were found as 0.922, 0.568, 1.18 and 1.04, respectively.

In the GLC determination, two different column systems, a 2% OV-17-Gas Chrom W-HP 100–200 mesh filled column and a 0.25 SE-52 fused silica capillary column, were used. Nitrogen was used in a filled column and helium was used in a capillary column. Mobile phase flow rates were set as 30 mL/min and a flame ionization detector was used with both column systems.

The linear concentration intervals were found in a range of 2–25 μL/mL in both methods. The R.S.D. for cocaine HCl, procaine HCl, lidocaine HCl, and caffeine were found to be 0.907, 0.948, 0.770, 0.901 in the filled column. For cocaine HCl, procaine HCl and caffeine R.S.D.'s of 0.774, 0.809, 0.814 were found, when a capillary column was used. In quantitative determinations, antipyrine was chosen as internal standard in the HPLC and GLC methods.