用AFM对质粒DNA在云母表面的自组装研究

通过原子力显微镜(AFM)对在云母表面上自然挥干的不同质量浓度的质粒DNA分子进行扫描，原子力显微镜图像显示：当质量浓度为0．1μg／mL时，DNA分子呈现出线性结构，随着质量浓度加大至1μg／mL，DNA分子相互缠绕为网状结构，质量浓度为10μg/mL时，呈现出具有典型的聚合形态，当质量浓度进一步加大到100μg／mL，则呈现出明显的树状脉络结构．通过原子力显微镜对质粒DNA分子的形态表征，可以看出质粒DNA分子具有典型的自组装的特性．     

CdCl2诱导秋粘虫细胞(Sf9)凋亡的初步研究

以秋粘虫（Spodoptera frugiperda Sf9）的细胞为材料，用不同浓度的CdCl2，通过Giemsa染色的形态学方法，研究其细胞凋亡．结果表明，在重金属离子的胁迫作用下，不同浓度的重金属离子致使细胞死亡率不同；其急性损伤域为136μmol／L；20μmol／L CdCl2作用6h后，Sf9细胞出现了凋亡小体．     

可吸入颗粒中金属元素对DNA的氧化性损伤

采用质粒DNA评价法评价哈尔滨市市区、郊区和清洁对照点的PM10和PM2.5样品的生物活性及颗粒物中金属元素对质粒DNA的氧化性损伤能力.研究结果表明,水溶样和全样样品都具有一定的活性,样品的TD40值为67.9～1 570 μg/mL,说明PM的生物活性主要与其来源和性质有关;颗粒物中具有生物活性的元素主要为过渡金属,其次为碱金属或其他主族元素,除过渡金属外,稀土元素对颗粒物的生物活性也具有显著影响.水溶样的TD40值与Y的浓度呈正相关,与La,Lu,Ho,Sm的浓度呈负相关,说明在对质粒DNA损伤过程中,Y拮抗La,Lu,Ho,Sm的损伤作用;全样的TD40值与元素Cs,La,Mn,Pb,Tm,Gd的浓度呈正相关,与Tb,Ni,Yb,Er,W,Cd,In的浓度呈负相关,在对质粒DNA损伤过程中,元素Cs,La,Mn,Pb,Tm,Gd协同拮抗Tb,Ni,Yb,Er,W,Cd,In的损伤作用.     

三种参对DNA氧化损伤保护作用的研究

利用CuSO4-Phen-Vc-H2O2-DNA化学发光体系，研究了红参、生晒参、西洋参对DNA氧化损伤的保护作用．探讨了DNA浓度、H2O2浓度、pH值等对DNA损伤发光强度的影响．实验发现，在DNA浓度为0．62μg／mL、H2O2浓度为1．1％、pH值为5．5等条件下，对DNA的保护作用为红参优于生晒参，生晒参优于西洋参．因为人参(红参和生晒参)所含的有效成分三醇皂甙的量比西洋参多，而红参由于加工过程不同，可产生新的抗氧化剂如maltol和水杨醛。     

Cu2+、Zn2+对舟形无齿蚌成熟钩介幼虫的毒害作用

报道了不同浓度的Cu^2 、Zn^2 对舟形无齿蚌成熟钩介幼虫的毒害实验．结果表明：Cu^2 在24h、48h、72h、96h时对钩介幼虫的半致死浓度分别为651．4μg／L、113．8μg／L、45．5μg／L、19．7μg／L；Zn^2 在24h、48h、72h、96h时对钩介幼虫的半致死浓度分别为10296．7μg／L、2612．3μg／L、171．1μg／L、15．9μg／L．在同一时间内浓度越高，钩介幼虫死亡率越大．在同一浓度下随时间延长，钩介幼虫死亡率增大．而半致死浓度随时间的延长却减小。     

氯化镉对条斑星鲽卵巢细胞的毒性作用及其机理研究

使用不同浓度的氯化镉（CdCl2）处理体外培养的条斑星鲽卵巢（BFO）细胞系细胞,利用毒理学和细胞生物学方法研究了重金属镉对BFO细胞的细胞毒性及其作用机理。毒性作用研究结果显示,BFO细胞对CdCl2敏感,浓度大于10ixmol／L的CdCl2对细胞的生长具有显著的抑制作用,能引起细胞内超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GST—Px）活性的持续降低和丙二醛（MDA）含量的持续升高,且具有浓度依赖性;机理研究结果显示．浓度大于40μmol／L的CdCl2可引起BFO细胞出现典型的凋亡细胞形态,BFO细胞在AO／EB荧光双染色中的质膜通透性显著提高,在单细胞凝胶电泳中出现明显的彗尾,且细胞凋亡率、彗尾的长度和亮度随CdCl2浓度的增加而逐渐升高,并具有浓度依赖性。可见,镉对BFO细胞具有显著的毒性作用,其毒性作用是通过诱导细胞凋亡来实现的,为利用BFO细胞系研究镉等重金属的细胞毒性及其作用机理奠定了基础。     

虫草菌提取物对HL-60细胞的抑制作用及G2/M期阻滞的诱导

对人工培养的虫草菌菌丝体提取物进行了体外抗肿瘤活性及其作用机理的研究．依次用石油醚、乙酸乙酯、乙醇和水提取人工培养的虫草菌菌丝体，分别得到石油醚、乙酸乙酯、乙醇和水提取物．采用MTT比色法检测发现乙酸乙酯提取物显著抑制类前骨髓白血病细胞HL-60的增殖活性，半数抑制质量浓度（IC50）约为25μg／mL．并采用流式细胞术和Western blotting等方法进一步研究虫草菌乙酸乙酯提取物抑制HL-60细胞生长的作用机理．用流式细胞仪检测HL-60细胞DNA含量发现，25μg／mL虫草菌乙酸乙酯提取物作用12～2Ah后，S期细胞减少，而G2／M期细胞增多，表明细胞周期中G2／M检验点被阻滞．Western blotting分析结果表明，在虫草菌乙酸乙酯提取物作用后，HL-60细胞中G2／M检验点相关周期蛋白p34^cdc2表达量降低．     

稀土元素La(Ⅲ)对质粒pUC18复制速度的影响

稀土应用的日益增长将会对生物的遗传产生深远的影响．生物的遗传离不开DNA的复制，由于染色体DNA非常巨大和复杂，难以直接研究稀土离子对其复制的影响．以细菌染色体之外的遗传因子——质粒为对象，研究La^3 对质粒DNA复制速度的影响．结果表明：在不同浓度La^3 存在下，质粒在宿主细胞中复制的速度不同；由于质粒复制与染色体DNA复制使用相同的酶系，因而可初步推断不同浓度的La^3 对染色体DNA的复制速度也有影响．     

酸性高锰酸钾化学发光体系测定针剂中的头孢噻肟钠

头孢噻肟钠碱性水解产物与高锰酸钾反应可产生微弱的化学发光，多聚磷酸对其有强烈的增敏作用，据此建立了一种简单、快捷、灵敏的流动注射化学发光测定头孢噻肟钠的新方法．化学发光信号ICL与头孢噻肟钠质量浓度C在0．02-20μg／mL和20～120μg／mL范围内呈良好的线性关系，回归方程分别表示为ICL=3.169＋20．961C（r=0．9998，n=9）；ICL=147．5＋14．752C（r=0．9994，n=9），方法的检出限为20ng／mL．对5μg／mL头孢噻肟钠进行11次平行测定，相对标准偏差为0．8％，用本法对针剂中头孢噻肟钠的含量进行了测定，得出了令人满意的结果．     

反胶团法萃取质粒DNA

采用新的TOMAC(甲基三辛基氯化铵)/2-乙基己醇/异辛烷反胶团体系,对该反胶团萃取质粒pUT649进行了研究.考察了表面活性剂浓度、离子浓度等对质粒DNA萃取的影响.当采用1.0%(volume)2-乙基己醇/异辛烷为有机相,TOMAC浓度为40 mmol.L-1,水相初始DNA浓度为25μg.mL-1时,质粒pUT649的萃取率可达90%以上.离子浓度对萃取过程有重要影响,反萃取时通过调节水相中的离子浓度,可以实现DNA和RNA的分离.研究结果表明,TOMAC/2-乙基己醇/异辛烷反胶团体系适合于核酸的萃取和纯化.     

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