Klebsilla pneumoniae XJ-Li甘油脱水酶的催化反应特性

以自主筛选的Klebsilla pneumoniae XJ-Li为甘油脱水酶酶源,研究了其催化反应特性和稳定性。结果表明,甘油脱水酶的最适催化反应温度和pH分别为40℃和8．0。温度在40℃以下,pH处于6．0～8．0之间时酶的稳定性较好。在常见金属离子中,Mg2＋和Mn2＋对甘油脱水酶的催化反应具有一定促进作用,而Ca2＋、Co2＋、Fe3＋、Zn2＋和Cu2＋对其活性均有抑制作用。此酶对甘油的最高耐受反应浓度在0．15mol／L左右,对1,2一丙二醇的饱和浓度在0．3mol／L左右,以甘油和1,2-丙二醇为底物时的反应动力学常数Km值分别5．57mmol／L和8．16mmol／L。     

小鼠胎儿成纤维细胞的冷冻保存研究

为了摸索小鼠胎儿成纤维细胞冷冻保存的简易方法,采用常规冷冻和玻璃化冷冻2种模式,探讨了不同的冷冻方法、不同的冷冻前平衡时间、不同的冷冻保护液的配比等因素对成纤维细胞冷冻效果的影响。实验结果表明:常规冷冻采用含10%(体积分数)甘油的DMEM液作保护剂,可将0~5℃下平衡时间缩短至45~60 min,细胞活力可达0.87。玻璃化冷冻采用10%(体积分数)NBS+1.8 mol/L乙二醇+0.1 mol/L蔗糖的PBS冷冻小鼠胎儿成纤维细胞效果好于其他组合,细胞活力可达到0.86。玻璃化冷冻法与常规冷冻法的冷冻效果差异不显著。     

强酸性阳离子交换树脂催化合成异丁醛1，2-丙二醇缩醛的研究

在强酸性阳离子交换树脂催化剂存在下,以异丁醛、1,2-丙二醇为原料,直接合成异丁醛1,2-丙二醇缩醛．分别研究了反应温度、反应时间、原料配比、带水剂、催化剂用量等条件对合成反应的影响,确定了最佳工艺条件：反应温度90-95℃,反应时间2．5h,n（异丁醛）：n（1,2-丙二醇）=1：1．2,催化剂用量1．5g,带水剂环己烷40mL（异丁醛为0．1mol的情况下）．异丁醛1,2-丙二醇缩醛的收率达到91．16％,产品纯度w（异丁醛1,2-丙二醇缩醛）达到98．5％以上．催化剂不经处理可多次循环使用．该催化剂具有价廉易得、催化活性好、不腐蚀设备、无环境污染等优点．     

乙二醇对速冻中小鼠胚胎发育的作用

利用快速冷冻方法处理小鼠2-细胞、4-细胞、8-细胞以及桑椹期的胚胎．用乙二醇作低温保护剂,浓度分别为0．5,1．5,2．5,3．5mol／L,其中含10％犊牛血清和0．25mol／L蔗糖,培养到囊胚阶段．结果发现,当乙二醇的浓度在2．5mol／L或以上时的保护效果较好．胚胎越处于较晚的发育阶段,越有较强的抗冻能力,同时也有较高的发育率．发育正常的胚胎移植后,受体均能分娩出正常的小鼠后代．     

羟胺-乙二胺-钴(Ⅱ)显色体系与甲醛质量浓度测定的研究

采用正交试验法研究了羟胺-乙二胺-钴(Ⅱ)的显色体系与甲醛反应的最佳条件．最 佳条件为5．00×10-2 mol／L羟胺溶液2．00 mL,1．00×10-1 mol／L乙二胺溶液3．0 mL,2．00×10-1 moL／L钴(Ⅱ)溶液5．00 mL,0．200 mol／L硫酸溶液0．80 mL,加热温度为55℃,加热时间为6 min．甲 醛质量浓度在0．080-3．200μg／mL范围内线性关系良好,检测下限为0．061 0 μg／mL,线性相关系数 为0．998 7．该法可用于饮用水加标回收率实验及脲醛树脂中的游离甲醛质量浓度检测．     

平衡方法及平衡和解冻温度对牛体外受精胚胎玻璃化冷冻保存效果的研究

以体外成熟、体外受精并体外发育的牛囊胚为实验材料进行玻璃化冷冻保存，分别探讨了防冻剂的平衡方法以及平衡和解冻温度对胚胎冷冻效果的影响．实验结果显示，在室温下（１８℃）以二步法或三步法添加防冻剂的冷冻效果，明显优于在４℃下，以二步法添加防冻剂的效果，其冷冻—解冻胚的发育率分别为６２．８％（５９／９４）、５３．１％（５２／９８）和１４．６％（１２／８２）（Ｐ＜０．０１）；另外，室温下以二步法玻璃化冷冻的胚胎，在２０℃水浴中解冻的发育率明显高于３７℃解冻的效果，６２．７％（３７／６２）、２６．２％（１６／６１）（Ｐ＜０．０１）．结果表明：体外成熟、体外受精的牛胚胎可以进行玻璃化冷冻保存，并能得到较高的培养存活率，在室温下，以二步法添加防冻剂，并于２０℃下解冻的玻璃化冷冻保存方法是一种快速、简便而有效的方法．     

Klebsilla pneumonia XJ-Li甘油脱水酶产酶条件研究

甘油脱水酶是生物法合成1，3-丙二醇的关键限速酶，对1，3-丙二醇的合成速度和发酵终浓度具有重要的影响。本文通过实验研究了Klebsilla pneumomae XJ-Li的基础产酶条件，结果表明：该菌株甘油脱水酶的合成与菌体的生长具有较好的偶联性，发酵8h即可达到最大产酶高峰，同时菌体生长也达到稳定期；其最适产酶条件为：温度40℃，oH值8．0，甘油浓度20g／L，氮源为6．0g／L的硫酸铵。     

坛紫菜(Porphyra haitanensis)叶状体细胞对4种有机溶剂的敏感性比较

分析了坛紫菜叶状体细胞对甲醇、乙醇、异丙醇、1，3-丙二醇等4种有机溶剂的敏感性．结果表明：体细胞对1，3-丙二醇敏感．在实验最低剂量(0．2μL／mL)下对紫菜体细胞就表现出较强的致死作用；对甲醇有较强的耐受性．在最高的1．0μL／mL处理浓度组．生长发育状况与对照组无明显差别；乙醇在浓度高于0.6μL／mL时强烈抑制体细胞的分裂；异丙醇随着浓度的升高表现出使体细胞向细胞团方向分化．而叶状体的形成则受到抑制．本实验结果表明．在用外源化合物处理紫菜叶状体细胞时．甲醇在1．0μL／mL浓度范围内可作为合适的有机溶剂。     

磷钨酸/硅胶催化剂催化合成苯甲醛1,2-丙二醇缩醛

以自制磷钨酸/硅胶为多相催化剂,以苯甲醛和1,2-丙二醇为原料合成苯甲醛1,2-丙二醇缩醛,采用正交试验探讨了合成苯甲醛1,2-丙二醇缩醛的影响因素.实验结果表明:固定苯甲醛物质的量为0.2mol,在n(苯甲醛)∶n(1,2-丙二醇)=1∶1.6,催化剂用量为反应物料总质量的0.75%,带水剂环己烷为10 mL,反应时间30 min的条件下,苯甲醛1,2-丙二醇缩醛的收率为75.9%.     

添加剂促进变性还原溶菌酶复性的作用

研究了多种添加剂促进变性还原溶菌酶复性的作用，考察了添加剂浓度及变性剂盐酸胍浓度对复性收率的影响．结果表明，精氨酸、乙酰胺、丙酮、硫脲及甘油均能有效促进变性溶菌酶复性，并且存在最佳的添加剂浓度使变性溶菌酶的复性收率最大．在促进复性中，乙酰胺等结构类似物与盐酸胍具有相同作用，因此，在降低复性液中盐酸胍浓度的同时，适当提高乙酰胺浓度即可获得较高的复性收率．当盐酸胍浓度为0．2mol／L时，复性收率达到90％时的乙酰胺浓度为2mol／L，但降低盐酸胍浓度至0．06mol／L时，达到相同变性收率的乙酰胺浓度需要4mol／L．甘油与盐酸胍存在着协同作用，在一定浓度的盐酸胍存在下，添加适量的甘油能获得较高的复性收率．     

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