酸提香菇多糖的抗氧化活性研究

以香菇柄为材料,利用稀盐酸浸提得到粗香菇多糖SP和净化分级后的香菇多糖SP2,在化学发光体系下研究两种多糖在清除超氧阴离子、清除羟基自由基、清除过氧化氢和抑制DNA氧化损伤方面的作用;用可见光比色法比较SP和SP2与VC和VE的还原能力大小;同时研究了两种多糖对H2O2诱导小鼠红细胞氧化溶血和小鼠红细胞自氧化溶血的影响以及在小鼠体内抗氧化效果。结果表明香菇多糖SP和SP2对超氧阴离子、羟基自由基和过氧化氢均具有清除作用和抑制DNA氧化损伤作用,从SC50值看出,香菇多糖经过纯化后作用减弱,这可能是因为香菇多糖之间或与其它物质有协同作用有关;可见光比色法表明SP和SP2具有还原能力,为表现抗氧化活性的可能提供了基础;SP和SP2对H2O2诱导小鼠红细胞氧化溶血以及小鼠红细胞自氧化溶血均有抑制效果;体内抗氧化试验表明SP和SP2可以减少小鼠体内肝组织丙二醛的生成,提高血清中超氧化物歧化酶的活力。研究为开发酸提香菇多糖功能性食品和香菇柄资源综合利用提供理论基础。     

蒲公英黄酮类物质的抗氧化活性

为研究蒲公英中黄酮类物质的抗氧化活性,分别应用NBT法测定去除超氧阴离子活性,Vc-Cu2 -Cyt·C反应体系研究清除羟自由基的能力,采取H2O2 及UV诱导的红细胞溶血实验研究总黄酮、芦丁和槲皮素的抗H2O2、UV破坏膜结构的能力.结果表明在清除O·2 、·OH及抗H2O2 诱导的红细胞溶血实验中总黄酮的活性都比芦丁和槲皮素及阳性对照组VitE较强,在UV诱导的红细胞溶血实验中略弱于VitE.说明蒲公英黄酮类物质具有较强的清除活性氧(ROS)的活性.     

丹皮酚及其磺化物体外抗氧化作用

为比较研究丹皮酚及其磺化物的体外抗氧化作用,测定了丹皮酚及其磺化物体外清除超氧阴离子自由基(O2.—)、羟自由基(.OH)的活性及对过氧化氢(H2O2)、紫外线(UV)诱导红细胞溶血的影响.发现丹皮酚和丹皮酚磺化物均具有较强的清除O2.—、.OH及抗H2O2、UV诱导的红细胞(RBC)溶血的活性,后者的抗氧化效应更强,甚至在一定程度超过作为阳性对照物的抗坏血酸.可以认为丹皮酚和丹皮酚磺化物可成为高效的天然抗氧化剂新资源.     

酸枣仁油抗氧化活性研究

以羟基自由基、超氧自由基清除能力、抗蛋白质糖基化反应及D-半乳糖氧化模型小鼠血液和肝脏中的MDA含量和GSH-Px活力的影响为指标,考察了酸枣仁油体内外抗氧化活性.结果表明,酸枣仁油清除羟基自由基的能力低于VE,总抗氧化力与VE相当,而清除DPPH自由基、超氧阴离子自由基能力和抗脂质过氧化作用都优于VE,说明酸枣仁油具有明显的体外抗氧化作用.体内试验表明,可以显著降低D-半乳糖氧化模型小鼠血、肝脏中的MDA含量,显著提高GSH-Px活力,说明酸枣仁油具有较好的体内抗氧化作用.     

北五味子木脂素对D-半乳糖致衰小鼠学习记忆能力的影响

目的探讨北五味子木脂素(Schisandra Chinensis baill lignans,SCL)对D-半乳糖(D-GAL)诱导的衰老小鼠学习及记忆能力的影响,为开发辅助改善记忆功能的保健食品提供依据.方法 ICR小鼠随机分为5组,即正常对照组(生理盐水皮下注射,蒸馏水灌胃)、衰老模型组(D-半乳糖皮下注射,蒸馏水灌胃)、SCL低(D-半乳糖皮下注射,SCL 35 mg/kg灌胃)、SCL中(D-半乳糖皮下注射,SCL 70 mg/kg灌胃)、SCL高(D-半乳糖皮下注射,SCL140 mg/kg灌胃)剂量组,连续给药10周.通过跳台实验和Morris水迷宫实验观察小鼠学习记忆能力;通过化学比色法检测小鼠脑组织中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)、一氧化氮合酶(NOS)的活性以及丙二醛(MDA)含量.结果 SCL能够明显提高D-半乳糖诱导的脑衰老小鼠学习记忆能力,能明显提高脑衰老小鼠脑组织中SOD,GSH-PX活性,降低NOS活性及MDA含量.结论 SCL能够改善D-半乳糖诱导的衰老小鼠学习记忆能力,其机制可能与其提高小鼠抗氧化能力相关.     

角叉菜不同溶剂提取物抗氧化活性

采用甲醇、乙醇、乙醚、乙酸乙酯、石油醚、丙酮6种溶剂分别对角叉菜进行冷浸提取.对提取物进行超氧阴离子自由基(.O2-)、羟自由基(.OH-)、H2O2诱导的小鼠红细胞氧化溶血和小鼠肝匀浆脂质过氧化的清除作用实验.结果表明,角叉菜不同溶剂提取物对各种自由基均具有一定的清除作用,而且溶剂对提取物活性有一定的影响.在相同的浓度下,对自由基的清除作用最大的分别为乙醚、丙酮、乙醚和乙酸乙酯提取物.     

北部湾金黄水母Chrysaora helvola Brandt刺细胞毒液溶血活性

【目的】探讨金黄水母Chrysaora helvolaBrandt刺细胞毒液(nematocysts venom,NV)的红细胞溶血活性特征及可能机制。【方法】通过分光光度法测定红细胞溶解释放血红蛋白的量来确认不同条件和药物对NV诱导红细胞溶血行为的影响。【结果】NV诱导的红细胞溶血与其总蛋白浓度存在依赖关系。溶液pH值、大分子非电解质渗透压保护剂PEGs均能显著影响其溶血活性;非电解质小分子糖类渗透压保护剂D-甘油和D-半乳糖对溶血活性影响很小,但D-葡萄糖能显著延缓溶血。NV同时具有Ca~(2+)依赖的弱磷酸酯酶A2(PLA_2)活性,且受组氨酸烷基化试剂p-BPB抑制。这一PLA2活性可能对其红细胞溶血活性也有贡献。【结论】NV的红细胞溶血活性可能由膜穿孔机制和所含PLA_2酶成分造成,并受到含葡萄糖单元结构的糖受体调节。     

叉鞭金藻多糖的分离纯化及体外抗氧化作用研究

叉鞭金藻多糖(DAP)经琼脂糖凝胶柱层析进行分级,得到了DAP-1和DAP-22个组分,分别对这2个组分进行了纯度和分子质量的测定,并考察了对羟自由基OH.、超氧阴离子O2-.的清除效果,以及对H2O2诱发小鼠红细胞氧化溶血的抑制作用和对小鼠肝匀浆脂质过氧化的抑制作用.结果显示,两个组份的组成相对均一,能显著或极显著清除OH.、O2-.,抑制小鼠红细胞溶血,并能显著抑制小鼠肝脂质过氧化的产生,且呈现剂量依赖性.其中DAP-2的抗氧化活性较DAP-1好,其对OH.、O2-.的清除率最高可达85.2%和76.0%,对小鼠红细胞的溶血抑制率和脂质过氧化的抑制率分别可达83.6%和89.3%.     

口服D-半乳糖致动物衰老效应的评价

目的评价口服D-半乳糖(D-galactose)的致衰老效应。方法实验选用NIH小鼠和Wistar大鼠,每日口服700mg/kg和皮下注射70 mg/kg D-半乳糖制备成衰老模型,Morris水迷宫(Morris-maze)检测动物学习记忆能力,生化方法测定小鼠脑MAO-B(Monoamine oxidase B)活性,肝脏SOD(Superoxide dismutase)和MDA(Malondialdehyde),含量、心肌脂褐素含量。结果口服D-半乳糖不影响小鼠体重增长,与对照组比较,无显著差异(P>0.05),而皮下注射D-半乳糖可使体重增长缓慢,与对照组和口服组比较差异极显著。口服D-半乳糖可降低小鼠和大鼠的学习记忆能力,使Morris迷宫作业时间(动物在水迷宫中由入水点至安全岛所用的时间,简称作业时间)延长,阿尼西坦可对抗D-半乳糖诱导的大鼠脑老化学习记忆减退的效应(P<0.01)。生化测定结果表明,口服D-半乳糖升高小鼠脑MAO-B活性和肝脏MDA含量、降低肝脏SOD活性、升高心肌脂褐素含量,与对照组比较,差异极显著(P<0.01),口服组与皮下注射组比较无显著差别(P>0.05)。结论小鼠和大鼠口服D-半乳糖能产生拟衰老效应,与皮下注射D-半乳糖诱导的衰老效应基本相似。     

紫草素对D-半乳糖/亚硝酸钠诱导痴呆小鼠学习记忆的影响

为观察紫草素对D-半乳糖/亚硝酸钠诱导的痴呆小鼠学习记忆的影响,采用D-半乳糖/亚硝酸钠诱导建立的痴呆小鼠模型,观察紫草素(2、4、8 mg/kg/d)对痴呆小鼠学习记忆的影响及对脑组织中丙二醛(MDA)含量和谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、乙酰胆碱酯酶(AChE)活性的影响。结果显示:给予紫草素8(mg/kg)/d对痴呆小鼠模型的学习、记忆具有明显改善作用。紫草素2、4、8(mg/kg)/d均可降低痴呆小鼠模型皮层及海马组织中MDA含量:紫草素各剂量组亦可明显增加痴呆小鼠海马组织中SOD活性,高剂量组可明显增加痴呆小鼠皮层组织中SOD活性,而紫草素8 mg/kg/d尚可增加皮层组织中GSH-Px活性;紫草素高剂量组对皮层和海马组织中AChE活性均有相对较弱的选择性抑制作用。由此可知,紫草素对痴呆小鼠学习记忆的改善作用可能与其降低脑组织中氧化应激水平及增强中枢胆碱能神经功能有关。     

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