木瓜SOD的提取及其活性测定方法的优化

目的 建立能准确测定木瓜超氧化物岐化酶(SOD)活性的测定方法。方法 采用单因素试验分析法,通过探究邻苯三酚自氧化反应体系的最大吸收波长、测定时间段、缓冲液pH值、邻苯三酚浓度和反应温度对自氧化速率的影响,建立了测定木瓜SOD活性的邻苯三酚自氧化法最佳应用体系;通过建立的木瓜SOD活性检测方法优化木瓜SOD提取条件。结果 邻苯三酚自氧化法最佳测定条件为:检测波长319nm,测定时间范围3.5min,缓冲液pH8.20,反应温度25℃,邻苯三酚浓度4.5mmol/L。木瓜SOD最佳提取工艺为:pH6.8的磷酸盐缓冲液、超声功率600W、超声时间20min浸提木瓜SOD,丙酮分级沉淀法纯化木瓜中的SOD,最终所得SOD用邻苯三酚自氧化法测定活性为529.72U/mg。结论 建立了能准确测定木瓜SOD活性的检测方法,并筛选得到木瓜最佳SOD提取条件。     

苗药刺梨SOD测定及其保存方法探讨

本实验采用邻苯三酚(PR)自氧化法测定不同干燥方法得刺梨样品中SOD的活力, 用透析法除去样品中的VC, 同时采用碘量法检测透析液中Vc的含量. 结果表明:经冷冻干燥获得的刺梨样品中SOD的活力值最大, 样品通过24h透析后, 可基本排除Vc含量对SOD活力测定的影响.     

邻苯三酚自氧化法在SOD活性测定中的应用

为了验证邻苯三酚自氧化法的准确性和实用性,对邻苯三酚在Tris-HCl和磷酸盐2种不同反应体系(缓冲液)中的自氧化产物进行UV-Vis吸收光谱扫描,确定其最适吸收峰;同时研究了tcv Cu,ZnSOD(简称tcvSOD)和Bovine Cu,Zn-SOD(简称Bovine SOD)分别在2种缓冲液中对邻苯三酚自氧化反应的抑制模式.波长扫描显示,终浓度为0.225mmol/L的邻苯三酚在50mmol/L Tris-HCl pH 8.2缓冲液中于320nm处30s出现明显吸收峰,30min吸收峰达到最高值;30min后440nm附近出现吸收峰;A320处的自氧化速率为0.139/min.同样浓度邻苯三酚在0.2 mol/L pH8.0磷酸缓冲液中除了A320的自氧化速率稍高(A3200.152/min)外,其他性质与50mmol/L Tris-HCl相同.tcvSOD和Bovine SOD在Tris-HCl缓冲液中对邻苯三酚自氧化反应的抑制作用较磷酸盐缓冲液为强.研究结果确认320nm可作为检测邻苯三酚自氧化、SOD对其产生抑制及SOD活性间接测定的特定波长.     

微量超氧化物歧化酶邻苯三酚/Vc测活法

在Vc终止剂法的基础上 ,邻苯三酚的加入量由终浓度2mmol/L降低为0.05mmol/L ,并提高反应溶液的 pH值至8.6 ,从而提高了SOD活力测定的灵敏度。使用本方法在SOD样品最大加入量1mL时 ,最低可检测到3.3×10-8 mol/(s·mL)SOD ,比Vc终止剂法灵敏度提高4倍。     

邻苯三酚自氧化法测定超氧化物歧化酶活性的研究

目前超氧化物歧化酶(SOD)活性测定结果混乱,为提高测定结果的可比性,对邻苯三酚自氧化法测定SOD活性的方法进行了研究,就该活力测定体系中缓冲溶液的介质组成、浓度、pH及所含的EDTA量等因素对测定结果的影响进行了探讨,根据实验结果,提出了新的改良方法.     

邻苯三酚自氧化法适于测定SOD活性吗?

用邻苯三酚自氧化法测定了Cu-ZnSOD(Superoxide dismutase，SOD）及根据天然超氧化物歧化酶活性部位结构设计、合成的一些模型化合物（the models of SOD，MSOD）活性。测试结果表明：Cu-ZnSOD和含Cu（Ⅱ）、Fe(Ⅲ)、Mn(Ⅱ、Ⅲ的SOD模型化合物随浓度升高，有的对邻苯三酚氧化表现为负抑制（即促进邻苯三酚氧化）；另一部分化合物在较低浓度表现为抑制，较高浓度表现为负抑制的交替变化；或抑制率的无规则变化。本文对出现负抑制的内在根源进行了探讨，鉴于邻苯三酚自氧化的复杂反应机理；含Cu(Ⅱ)、Fe(Ⅲ)、Mn（Ⅱ、Ⅲ）SOD模型化合物的多酚氧化酶活性和Fenton反应催化活性，及MSOD中金属离子的Lewis酸性，不宜采用邻苯三酚自氧化法测定SOD活性。     

盐地碱蓬超氧化物歧化酶的提取及抗氧化活性的研究

以盐地碱蓬为原料提取超氧化物歧化酶(SOD),采用邻苯三酚自氧化法对其酶活进行测定。实验结果表明:10g盐地碱蓬中提取的SOD,经硫酸铵分级沉淀、氯仿/乙醇沉淀、丙酮沉淀及热处理后,酶活分别为427.035U/mg、648.6736U/mg和1181.856U/mg。     

应用极谱氧电极检测SOD活性研究

本文建立 SOD 活性测定的极谱氧电极法,同时比较了邻苯三酚和肾上腺素自氧化系统的工作条件和优缺点,结果提示,肾上腺素自氧化系统的最适条件为:30℃,0.1mol/LpH10.3碳酸缓冲液4.0ml,0.05mol/L 肾上腺素30μl,SOD 在0-0.8μg 间与产氧量成线性关系;邻苯三酚系统的工作条件与文献报道一致.实验发现肾上腺素系统灵敏度较高,但线性范围小,重复性与邻苯三酚系统一致.本文还应用极谱氧电极法筛选抗氧化天然活性物质,在若干动物、植物及酵母中进行了SOD 活性测定,证明该法简便、快速、灵敏。     

蛹虫草SOD酶活力的测定与分析

文章采用改良的邻苯三酚自氧化法，比较了不同种类的蛹虫草样品及相同种类的蛹虫草不同部位之间的SOD酶活力，结果表明不同种类的蛹虫草发酵菌丝体和发酵液之间的SOD酶活力有较大的不同，蛹虫。草发酵液具有良好的发展前景，为蛹虫草SOD的开发和利用提供了科学依据。     

连翘叶的体外抗氧化活性研究

对连翘叶的体外抗氧化活性及药用价值进行了探讨.酶活力的测定采用邻苯三酚自氧化微量法.用Fenton法研究连翘叶茶提取物(FSE)清除.OH的效果.结果证明FSE具有明显的抗氧化的作用.     

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.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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-