HPLC法测定金不换各部位中大黄酸、大黄素含量

采用高效液相色谱法测定河南栽培金不换中大黄酸、大黄素的含量,色谱柱为Hy-persilC18柱(250mm×4.6mm×5μm),流动相:甲醇∶0.25%磷酸(体积比80∶20),流速:1.1mL/min,检测波长为436nm.结果:大黄酸在0.154～1.54μg/mL、大黄素在0.412～2.06μg/mL范围内其峰面积积分值与质量浓度之间呈良好的线性关系(r=0.999 6和0.999 9),平均回收率分别为100.2%、99.87%(n=6),RSD分别为1.47%、2.1%.该方法简便、准确,可用于金不换中大黄酸、大黄素含量的测定.     

超滤质谱法研究大黄蒽醌类化合物与人血清白蛋白的相互作用

为研究药物小分子与靶蛋白的相互作用,建立了超滤技术和液相色谱电喷雾质谱联用方法(LC-ESI-MS),并用该法筛选了与人血清白蛋白(HSA)的作用的大黄蒽醌类物质(大黄酚、大黄酸、芦荟大黄素).通过比较大黄蒽醌类药物混合溶液与HSA结合前后的提取离子流图色谱峰,发现大黄酸与HSA结合能力最强,芦荟大黄素次之,大黄酚最弱.说明超滤质谱法是研究药物小分子和蛋白质相互作用的一种快速灵敏的分析方法.     

虎杖灌胃大鼠血尿中蒽醌类代谢物的LC-MS分析

通过检测虎杖提取物灌胃后大鼠血浆及尿液中的代谢产物, 建立一种用液相色谱 电喷雾串联质谱（LC-MS）分离鉴定复杂样品中主要蒽醌类代谢物的方法. 液相色谱条件： 色谱柱为Agilent XDB-C18（4.6 mm×250 mm, 5 μm）, 流动相为水 甲醇梯度洗脱, 柱温为25 ℃. 质谱条件： ESI离子源, 毛细管电压3.5 kV, 负
离子检出模式. 结果表明: 在大鼠灌胃虎杖提取物后的血浆样品中检测出大黄素、 大黄酚和大黄素甲醚3种代谢产物; 尿液中检测出大黄素、 大黄素葡萄糖醛酸酯、 芦荟大黄素硫酸酯和芦荟大黄素葡萄糖醛酸酯4种代谢产物.     

HPLC法比较狼毒大戟不同产地游离蒽醌和总蒽醌的质量分数

建立了同时测定狼毒大戟中芦荟大黄素、大黄素、大黄酚、大黄酸和大黄素甲醚5种蒽醌类成分的HPLC法.采用Venusil MP C18(2)柱(4.6mm×250mm,5μm)色谱柱,以甲醇-0.2%磷酸溶液(79∶21)为流动相,流速1.0mL/min,检测波长254nm,柱温30℃.测定了16批狼毒大戟根和地上部分中5种蒽醌类成分的质量分数,结果表明,在线性范围内的线性关系(r0.999 3)及分离度(R1.5)均良好;游离蒽醌平均回收率为96.59%～99.13%,RSD≤1.36%;总蒽醌平均回收率为97.60%～99.46%,RSD≤1.52%.16批狼毒大戟样品中5种蒽醌类成分均可检测到,不同产地、不同部位的狼毒大戟中芦荟大黄素、大黄酸、大黄素、大黄酚、大黄素甲醚量及组成结构比存在较大差异;由聚类分析可知,同一产地、不同居群狼毒大戟根的总蒽醌质量分数并没有聚集在一枝上;同时根的总蒽醌质量分数高于地上部分,云南省香格里拉市格咱乡除外.由此表明,这不仅能比较云南产狼毒大戟不同产地、不同部位中游离蒽醌和总蒽醌的质量分数及组成的差异性,为其药材质量评价和资源合理利用提供科学依据;也为狼毒大戟地上部分的综合利用提供了理论依据.     

大黄素等游离型蒽醌诱导肿瘤细胞凋亡的信号转导通路

以大黄素、芦荟大黄素、大黄酸的药理作用为基础，综合分析了它们诱导多种肿瘤细胞凋亡的信号转导通路．并且对有关问题给予说明．结论是，大黄素、芦荟大黄素、大黄酸可诱导多种肿瘤细胞的凋亡响应，但仍有许多细节有待于进一步探讨．     

唐古特大黄蒽醌衍生物的提取与分离

将唐古特大黄粉末加到20%硫酸溶液和氯仿的混合液中,在水浴回流以水解、提取.氯仿提取液依次以5%碳酸氢钾、5%碳酸钠、0.25%氢氧化钾和5%氢氧化钾振荡提取.提取液分别以盐酸酸化,即分别得大黄酸、大黄素、芦荟大黄素和大黄酚———大黄素甲醚混合物黄色沉淀物.后者再以薄层硅胶干柱层析分离,可得大黄酚和大黄素甲醚单体.上述五种蒽醌成分再经结晶即得纯品.     

高效液相色谱同时测定何首乌中大黄酸、大黄素和大黄酚的含量

采用高效液相色谱法建立了同时测定何首乌中大黄酸、大黄素、大黄酚三种蒽醌类化合物的方法,样品采用超声波法提取,色谱柱为Phenomenex C18(250mm×4.6mm,5μm);流动相为甲醇-0.4%醋酸水溶液(80∶20);流速0.80mL/min;紫外检测波长254nm;柱温为35℃.结果:该方法对大黄酸、大黄素和大黄酚分别在0.0001~12.50μg/mL、0.0002~25.00μg/mL、0.00018~22.50μg/mL范围内线性关系良好,相关系数(r)均大于0.9999,定性检测限(S/N=3)依次是:0.0703ng/mL、0.0282ng/mL、0.0871ng/mL;样品回收率为88.39%~107.2%.结论:本法操作简单快速、定量准确、灵敏度高、成本低,为何首乌中蒽醌类化合物的检测分离及含量测定提供了一个有效的科学方法.     

大黄蒽醌类化合物电喷雾质谱研究

采用电喷雾-离子阱质谱(ESI-ITMS)法,通过一级质谱全扫描和二级质谱碰撞诱导解离技术,研究5种大黄蒽醌衍生物(大黄素、芦荟大黄素、大黄酸、大黄素甲醚、大黄酚)的质谱行为及分子结构与裂解规律间的关系,并对大黄药材中总游离蒽醌提取物进行了电喷雾质谱检测.实验结果显示,5种大黄蒽醌类化合物一级质谱负离子出峰较好,被测样品均为基峰或第二强峰,未发现聚合体离子及加合离子产生,二级质谱各碎片离子归属明确,特征性强.实验结果可应用于大黄蒽醌类化合物的结构分析及进一步的代谢产物研究,并为大黄药材有效成分的鉴定提供了一种快速,灵敏的检测方法.     

芦荟中蒽醌类化合物成分研究

利用聚酰胺、硅胶柱色谱,结合溶剂分配及重结晶技术,从芦荟叶液汁的浓缩物提取物中分离得到6种蒽醌类化合物,经综合波谱分析和化学方法鉴定它们的结构,结果为芦荟大黄素(aloeemodin)、大黄素甲醚(physi cion)、大黄酚 (chrysophanol)、大黄素 (emodin)、大黄酸 (rhein)及一个自然界新发现的化合物:1,8-二羟基-9,10-蒽酮3-甲基-(2羟基)丙酸酯 (1,8-dihydroxy-9,10-anthraquinone-3-methyl-(2-hydroxy)propionateester)。     

高速逆流色谱分离制备大黄化学成分

采用pH-区带精制逆流色谱(pH-ZRCCC)与常规高速逆流色谱(HSCCC)结合技术分离制备大黄粗提物中的化学成分。首先采用pH-ZRCCC分离大黄粗提物,溶剂体系为石油醚-乙酸乙酯-甲醇-水(3:7:4:6,V/V),上相加TFA(10 mmol/L)作为固定相,下相加Na OH(15 mmol/L)作为流动相。从1.3 g粗提物中得到140 mg桂皮酸(纯度为96.1%)、130 mg大黄酸(纯度为92.5%)和560 mg尾吹物。称取260 mg该尾吹物采用常规HSCCC的方法进一步分离,溶剂体系为石油醚-乙酸乙酯-甲醇-水(7:3:7:4,V/V),得到约98 mg大黄素(纯度为96.5%)和60 mg芦荟大黄素(纯度为94.6%)。用HPLC检测纯度,用ESI-MS和1HNMR鉴定结构。研究结果表明pH-ZRCCC与HSCCC结合是分离大黄中化合物的一种有效方法。     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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