HPLC-ESI-MS~n法分析西藏秦艽花和川西秦艽花中的7种成分

目的:采用HPLC和电喷雾质谱联用技术分析西藏秦艽花与川西秦艽花中的7种化学成分.方法:液相色谱条件色谱柱:Agilent Zorbax ODS(5μm,4.6 mm×250 mm);流动相:乙腈(A)-0.4%醋酸水溶液(B)进行梯度洗脱;体积流速为0.4 m L/min;检测波长254 nm;电喷雾质谱采用负离子模式采集.结果:采用HPLC-ESI-MS~n法分析西藏秦艽花和川西秦艽花中的7种成分,分别为獐牙菜苦苷、异牡荆黄素、落干酸、龙胆苦苷、异荭草苷、獐牙菜苷及6'-O-β-D-葡萄糖基龙胆苦苷.结论:HPLC-ESI-MS~n联用分析法可以鉴定分析西藏秦艽花和川西秦艽花中的7种成分,为该属植物成分的质量控制提供了科学依据.     

山楂叶提取物中牡荆素、金丝桃苷、异槲皮苷对照品的制备

采用高速逆流色谱结合半制备液相色谱技术快速分离山楂叶中低含量的牡荆素、金丝桃苷、异槲皮苷单体。以氯仿-甲醇-水-正丁醇(4∶3∶2∶1.5,V/V)为溶剂系统,流速为5.0 m L/min,转速为850 r/min,检测波长为254 nm,从山楂叶黄酮提取物中富集得到含牡荆素、金丝桃苷、异槲皮苷3种化合物的混合组分,经半制备液相进行二次分离纯化,得到纯度大于98%的牡荆素、金丝桃苷、异槲皮苷单体。研究结果表明,该技术对山楂叶中低含量黄酮类化合物的分离快速、高效,且纯度高。     

坚龙胆不同部位中龙胆苦苷的含量比较

目的：测定坚龙胆不同部位龙胆苦苷的含量,并评价坚龙胆药材不同部位的质量。方法：采用HPLC法,色谱条件为Agilent ZORBAX SB C18色谱柱（4.6mm×150mm,5μm）,流动相为甲醇∶水（27∶73）,检测波长274nm,流速1.0ml/min,柱温25℃。结果：测定了坚龙胆药材不同部位中龙胆苦苷的含量。龙胆苦苷在0.21～10.5μg范围内线性关系良好,r值为0.999 8,龙胆苦苷平均回收率为98.01%,RSD为2.50%。结论：坚龙胆药材不同部位龙胆苦苷含量均高于《中国药典》2005年版要求,表明坚龙胆全草均可入药。     

水竹叶的化学成分

采用硅胶、 聚酰胺和Sephadex LH-20等柱层析方法, 首次从水竹叶乙醇提取物中分离得到4种化合物. 利用核磁共振氢谱和碳谱等波谱鉴定为木犀草素（luteolin, 1）、 异牡荆苷（isovitexin, 2）、 异荭草苷（isoorientin, 3）和荭草苷（orientin, 4）.     

微籽龙胆中黄酮苷类化学成分及其抗氧化活性研究

为研究药用植物微籽龙胆(Gentiana delavayi Franch)的活性物质基础,采用多种色谱技术(硅胶、ODS、MCI和Sephadex LH-20等)从微籽龙胆中抗氧化活性最好的正丁醇部位分离得到8个黄酮苷类化合物.通过核磁共振技术和文献数据对比,将其分别鉴定为:木犀草素-6-O-β-D-葡萄糖苷(1),牡荆苷(2),芹菜素-7-O-β-D-葡萄糖苷(3),异牡荆素(4),葛根素(5),hypolaetin-8-O-β-D-glucoside(6),荭草素(7)和异荭草素(8),化合物1和6为首次从该属植物中分离得到.此外,测试了微籽龙胆各萃取部位和上述化合物的抗氧化活性.黄酮苷类化合物6和7表现出显著的DPPH自由基清除能力,其中化合物7的活性与阳性对照相当,其IC50值为(9.74±0.05)μg/mL.     

正交试验法优选坚龙胆中龙胆苦苷的提取工艺

目的:优选坚龙胆中龙胆苦苷的提取工艺.方法:以龙胆苦苷的含量为指标,采用高效液相色谱法进行含量测定,采用L9(34)正交设计试验,对提取次数、提取溶剂倍数和提取时间3因素进行考察,以确定最佳提取工艺.结果:提取3次,用10倍量的甲醇,提取时间每次20min为最佳提取工艺.结论:该工艺合理,且稳定可行.     

超声提取-HPLC法测定秦艽中龙胆苦苷的含量

目的 用高效液相色谱法测定秦艽样品中龙胆苦苷的含量。方法采用水提法为对比,以水、乙醇和甲醇为溶剂,用频率为20kHz的超声波提取秦艽中的龙胆苦苷,并用HPLC法测定样品中龙胆苦苷的含量,并对两种工艺的秦艽样品的主体成分龙胆苦苷进行定量比较。结果表明超声提取能够明显地提高秦艽中龙胆苦苷的浸出率。结论通过运用正交试验法,确定了秦艽的粒径大小(目数)、超声波处理时间(min)以及水剂量(mL)3个因素的最佳组合。     

高速逆流色谱分离纯化番泻叶中的苷类化合物

采用高速逆流色谱法从中药番泻叶中快速分离得到4个苷类化合物,溶剂体系为正丁醇-水(9:10,V/V),流速2.0 m L/min,检测波长280 nm,转速860 r/min。从200 mg番泻叶正丁醇萃取物中分离得到10 mg芹菜素-6,8-二-C-葡萄糖苷、9 mg山奈酚-3-O-β-D-龙胆二糖苷、15 mg异鼠李素-3-O-β-D-龙胆二糖苷和5 mg番泻苷B,纯度分别为97.6%、98.9%、98.3%和99.3%。该方法稳定、高效,适合番泻叶中苷类化合物的分离纯化。     

优化提取工艺对龙胆中两种苦苷提取率的影响

考察不同提取方法对龙胆中龙胆苦苷和獐牙菜苦苷提取率的影响.采用高液相色谱分析法,比较甲醇超声提取、甲醇冷浸提取、水煎煮提取、乙醇渗漉提取四种样品制备方法对龙胆苦苷和獐牙菜苦苷提取率的影响.其中乙醇渗漉提取法对两种成分提取效率高;同时确定了最佳渗漉条件.该提取方法操作简便易行,提取效率高,可用于药材龙胆及其制剂的质量分析.     

不同光质对滇龙胆药材干燥品质的影响

研究不同光质滇龙胆药材干燥品质的影响,利用遮光、红色、黄色、蓝色、绿色、紫色6种不同光照条件,将晒干方式作为对照,重点考察干燥后滇龙胆内水分含量及龙胆苦苷含量,同时对另外2种滇龙胆内主要活性成分马钱苷酸、獐牙菜苦苷进行了测定.结果显示绿光能降低其水分含量,并显著提高滇龙胆内龙胆苦苷的含量、马钱苷酸、獐牙菜苦苷的含量,为...     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the