银杏萜内酯在反相高效液相色谱中保留行为

以水－甲醇为流动相和IntertsilODS3为固定相，系统地研究了银杏萜内酯的反高效液相色谱上保留行为。研究表明，角杏萜内酯容量因子的对数和流动相中甲醇含量呈线形关系，其相关系数γ大于0．965。     

GC-MS法测定银杏内酯B(原料药)中石油醚残留量

作者建立了检测银杏内酯B(原料药)中石油醚(60～90℃)残留的方法.以甲醇为萃取溶剂,采用超声提取法对样品进行前处理,采用气相色谱-质谱联用法进行检测.结果表明:该法在5 min内能较好地分离石油醚的所有组分,样品的加样回收率(n=6)为98.8%,RSD为2.55%,低检测限为1.61×10-5μg.该法具有灵敏、准确、快速等特点.     

银杏叶中银杏内酯的提取、分离和测定方法研究

银杏叶中银杏内酯的提取,对溶剂萃取法和溶剂萃取——柱提法进行比较,实验证明,利用溶剂萃取法所得银杏内酯含量明显高于溶剂萃取——柱提法,是一种操作简单、能耗低且银杏内酯含量较高的方法。银杏内酯的含量测定,实验中采用高效液相色谱(HPLC)测定银杏提取物(GBE)中银杏内酯含量的优化方法,GBE用甲醇溶解后,经酸性氧化铝柱净化,由反向HPLC测定银杏内酯含量,该方法快速、有效,准确度高,重现性好。可用于银杏叶及其提取物(GBE)中银杏内酯的快速测定和分析。     

银杏萜内酯A、B、C和白果内酯的热特征分析

研究银杏萜内酯A、B、C和白果内酯的热特征并探讨鉴定这些化合物的新方法.用热重分析法(TGA)和差示扫描量热法(DSC)分别对银杏萜内酯A、B、C和白果内酯进行热特征分析.所有样品的热重(TG)和微商热重(DTG)曲线都有各自的谱图特征,其DSC曲线的峰形、峰位置和峰值也有特征;银杏萜内酯A、B、C的稳定性较差,不能准确测得其熔点;白果内酯受热稳定,能够测得其熔点.利用TGA和DSC法容易鉴定银杏萜内酯A、B、C和白果内酯.用TG-DTG法对银杏萜内酯A、B、C和白果内酯在非等温条件下进行热分解动力学研究,把从TG-DTG曲线中得到的数据和30个不同的方程采用Achar微分法和Madhusudanan-Krishnan-Ninan(MKN)积分法对其进行非等温分解动力学研究,得到动力学参数活化能(E和指前因子A)和分解动力学机理及方程.     

银杏叶中银杏内酯提取工艺研究

以银杏内酯(白果内酯、银杏内酯A、银杏内酯B和银杏内酯C)的提取率为指标,确定银杏叶乙醇提取的最佳提取工艺。采用正交试验设计的方法,系统考察提取时间、料液比、乙醇体积分数和提取次数4个因素对银杏叶提取工艺的影响。以异丙醇为流动相,优化高效液相色谱法(HPLC ELSD)测定银杏内酯的含量,并计算提取率。实验得出最佳提取工艺条件为提取时间1.5 h、料液比1：20、乙醇体积分数50%、提取次数3次。本工艺可以提高银杏内酯的提取率,节约试验成本,适用于工业化生产。     

高速逆流色谱法分离野马追乙酸乙酯萃取物中三种倍半萜烯内酯

建立了应用高速逆流色谱(HSCCC)从野马追乙酸乙酯萃取物中分离纯化3种倍半萜烯内酯的方法.采用正己烷-乙酸乙酯-甲醇-水(1:4:2:3)作为两相溶剂体系,从900mg野马追乙酸乙酯萃取物中分离得到3β-Hydroxy-8β-[4′-hydroxytigloyloxy]-costunolide 6.5 mg,野马追内酯A28.5mg和野马追内酯B29.3 mg,其纯度分别为92.5%,91.7%和93.9%.3种化合物的结构通过ESI-MS和1H NMR进行了鉴定.     

高速逆流色谱制备雷酚内酯异构体的研究

以选定的溶剂体系为基础,研究温度、转速对高速逆流色谱技术分离制备雷酚内酯异构体工艺的影响。研究结果表明,在选定的溶剂体系(正己烷∶乙酸乙酯∶甲醇∶水=2∶3∶3∶2,V/V/V/V)下,流动相流速为2.0 mL/min时,正向洗脱,分离较佳的恒温水浴循环水温度为25.0℃、转速为800 r/min,此时管柱内固定相的保留率为60.0%,管路工作压力为0.15 MPa。     

银杏内酯的药理作用

银杏内酯为银杏叶提取物及其制剂中的主要药效成分,具有抗血小板活化因子（简称PAF）活性。文中对近几十年关于银杏内酯的药理学研究进行了综述。药理学研究表明,银杏内酯（特别银杏内酯B）是血小板活化因子强有力的拮抗剂,具有抗血小板聚集、抗血栓、防治动脉粥样硬化、抗炎症和抗过敏等作用。     

银杏内酯的药理作用

银杏内酯为银杏叶提取物及其制剂中的主要药效成分,具有抗血小板活化因子（简称ＰＡＦ活性,文中对近几十年关于银杏内酯的药理学研究进行了综述．药理学研究表明,银杏内酯（特别银杏内酯Ｂ）是血小板活化因子强有力的拮抗剂,具有抗血小板聚集、杭血栓、防治动脉粥样硬化、抗炎症和抗过敏等作用．     

银杏内酯C标准样品的研制

以《标准样品工作导则(3)标准样品 定值的一般原则和统计方法》为依据,研制银杏内酯C的国家标准样品。样品原料为银杏科植物银杏Ginkgo biloba L.的干燥叶,采用硅胶柱色谱和Sephadex LH-20凝胶柱色谱技术,结合制备液相精制,纯化和制备了银杏内酯C,并通过紫外、红外、质谱和核磁共振等技术手段进行了结构确认。进行了薄层色谱鉴别,建立了液质联用分析技术,进行了均匀性、稳定性和定值实验。结果表明,样品均匀性良好,在0~4 ℃ 储存条件下2年内稳定,定值结果确定其纯度为(99.85±0.06)%。研制的银杏内酯C符合国家标准样品的要求,可用于与银杏内酯C相关产品的含量测定、质量控制和检测方法的评定等。     

毛细管气相色谱法测定银杏叶中萜内酯含量

建立了对银杏萜内酯的毛细管气相色谱(CGC)分离条件,使萜内酯成分BB,GA,GJ,GB,GC获得良好分离。合理选择了内标物角鲨烷(SQ),理论计算并直接测定了银杏萜内酯的相对质量校正因子,且可靠性好。采用内标法定量测定了组分的含量。BB,GA,GB,GC回收率分别为92.8%,93.2%,92.4%,94.4%,5种银杏萜内酯相对标准偏差为2.9%,1.6%,2.2%,1.9%,1.9%。     

银杏内酯B(BN52021)对家兔脑缺血再灌注的抗氧化作用

目的:探讨银杏内酯B(BN52021)在抗氧化方面对脑缺血再灌注保护作用.方法:家兔麻醉后结扎双侧颈总动脉,10分钟后解开丝线再灌注60分钟.反复两次,3小时后取血测血清中超氧化物歧化酶(SOD)、丙二醛(MDA)、一氧化氮(NO)的含量,断头处死家兔,测脑组织中Na ,K -ATP酶的活力.结果:银杏内酯B能显著降低模型家兔的MDA含量、增加SOD活力和NO的含量,增加脑匀浆中Na ,K -ATP酶的活力.结论:证明银杏内酯B对家兔脑缺血灌注有抗氧化作用,能保护缺血脑组织.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.