动性球菌产生胞外脂肪酶的条件

测定了动性球菌产生胞外脂肪酶的酶活力,对动性球菌产生胞外脂肪酶的条件进行了研究.结果表明,当碳源为葡萄糖,氮源为蛋白胨,初始pH值为6.0时脂肪酶产率最高;K2HPO4,KH2PO4,CaCl2,ZnSO4和NaCl对脂肪酶产率有促进作用;CuSO4和MgSO4对脂肪酶产率有一定影响;FeCl3,BaCl2,CoSO4和MnSO4对脂肪酶产率影响较大;非离子表面活性剂吐温和聚乙烯醇均能促进脂肪酶的生成,且吐温比聚乙烯醇效果更好.     

漆酶/脂肪酶催化制备丝裂霉素类似物及其响应面法优化

丝裂霉素及其类似物,广泛应用于各种肿瘤.为了获得优异的产率和环境友好性,采用一锅法工艺,以漆酶/脂肪酶为催化剂,催化2-甲基苯-1,4-二酚与正丁胺的多米诺反应制备丝裂霉素类似物2-丁胺-3-甲基-1,4-苯醌(c).采用响应面技术优化了反应条件:2-甲基苯-1,4-二酚与胺的物质的量比为1.16∶1、漆酶与脂肪酶的活性比为1.14∶2、反应温度为38.9 ℃,最佳产率达到87.17%.建立了产率模型,该模型考虑了2-甲基苯-1,4-二酚与胺的物质的量比、漆酶与脂肪酶活性比和反应温度对产率的影响,可以准确的预测产率(R²为0.994 1).漆酶/脂肪酶协同催化体系一锅法合成丝裂霉素类似物,显著提高了产率,可作为提高丝裂霉素类似物产率的绿色替代工艺.     

大白鼠实验性肝病变的组织化学和生物化学研究 Ⅰ.四氯化碳中毒后肝内脂肪、脂肪酶、核糖核酸和硷性磷酸酶的观察及血、肝内转氨酶活力的变化

大白鼠皮下注射一定剂量的CCl_4(2C.C./100克体重40%的CCl_4)后24及48小时出現显著的肝脂肪病变,此时血內轉氨酶活力由正常时的175.5单位上升至924与908单位,同时肝組織內轉氨酶活力則由正常时的159单位分別下降至79及59单位。因此我們认为,由CCl_4引起的这样肝病变时血內轉氨酶的上升可能系由中毒的肝組織而釆。在注射CCl_4后的动物肝組織中有某些数量的肝细胞由于肿胀而成气球细胞,此类细胞用一般組織学及組織化学方法观察,无脂肪的积聚,亦无脂肪酶、核糖核酸及硷性磷酸酶的存在;由于此类細胞的出現,致使肝血变狭窄,影响了肝細胞的血液供应,而使肝小叶中央細胞坏死。我們也观察到,在肝病变过程中,靠近中央靜脉周围单核浸澗細胞較多,此类細胞中的核糖核酸及硷性磷酸酶均呈阴性反应。在浸潤細胞间有小型肝細胞的存在,此种細胞形状較小,其細胞質的嗜伊紅性較强,其中硷性磷酸酶及核糖核酸則呈阴性反应;致使核糖核酸及硷性磷酸酶在病变后臂由正常分布形式而集中于肝門管附近的肝細胞及肝胆管周围。我們認为,硷性磷酸酶的集小于肝门管区是由于气球細胞的胀大阻塞了血,而胆毛細管的收縮又妨碍了磷酸酶由肝至胆道的去路。CCL_4注射48小时后大白鼠肝內的核糖核酸集中于肝門管区,被認为是肝細胞的再生現象。本实驗观察到,CCl_4中毒后肝脂肪的产生与肝細胞內脂肪酶的阴性反应,这可能与肝細胞內脂肪酶的减低有关,是由于CCl_4破坏了肝內脂肪酶的活性所致。     

动性球菌代谢变压器绝缘油及其代谢产物对绝缘油介损的影响

对动性球菌代谢变压器绝缘油进行了研究, 发现动性球菌能够代谢绝缘油 , 利用薄层层析、 液-质联机等技术从变压器绝缘油的动性球菌代谢物中分离得到一种脂 肪酸, 用质谱、 核磁共振对其结构表征. 同时研究了动性球菌代谢绝缘油的产物对绝缘 油介损的影响.     

pH和温度对黑斑蛙消化道脂肪酶活力的影响

采用聚乙烯醇橄榄油乳化液水解法,对黑斑蛙(Rana nigromaculata)消化道不同部位脂肪酶活力进行了测定并考察了pH和温度对脂肪酶活力的影响.结果表明,黑斑蛙消化道不同部位脂肪酶活力由高到低依次是中肠、后肠、前肠、胃和食道.pH和温度对脂肪酶活力的影响较大,二者与脂肪酶活力的关系曲线均呈单峰型,胃和肠道脂肪酶的最适pH值分别为5.0和7.5,最适温度均为40℃.此外对蛙类的人工养殖提出了几点建议.     

响应面优化脂肪酶催化Baeyer-Villiger反应制备ε-己内酯

固定化T.laibaccii脂肪酶介导化学-酶Baeyer-Villiger氧化法制备ε-己内酯.运用响应面法进行了实验设计,获得了最优反应条件：环己酮初始浓度为1.22 mol/L,环己酮与过氧化氢脲的物质的量比为1∶1.3,反应温度为56.5℃,产率达到98.06%,浓度高达1.2 mol/L.在环己酮、乙酸乙酯反应体系中有三个反应,其中第三个反应是过氧化氢脲通过固定化脂肪酶的作用与中间产物乙酸反应,乙酸原位生成过氧乙酸.建立了二次多项式模型,其R²值为0.998 8,可以准确地预测ε-己内酯产率.该模型考虑了环己酮的初始浓度、环己酮与过氧化氢脲的物质的量比和反应温度对ε-己内酯产率的影响,环己酮与过氧化氢脲的物质的量比对ε-己内酯的产率有非常显著的影响(p<0.000 6).     

胞外聚合物(EPS)的检测及受金属离子胁迫作用 的研究进展

胞外聚合物(EPS)是细胞外由微生物分泌的一种三维空间的大分子聚合物,其在污水生物处理系统中具有重要的作用.胞外聚合物具有一定吸附性能,使其在污水净化、环境治理方面有一定优势,既能吸附有机混合物,又能吸附无机金属离子,有很好的解毒作用.生物膜中一些金属离子的存在会对胞外聚合物产生相关影响,如Cu~(2+)、 Pb~(2+)、 Ni~(2+)、Al~(3+)等.对于胞外聚合物的提取,有高速离心法、加热法、EDTA法、NaOH法、超声法、CER法等,不同提取方法会对胞外聚合物的组分产生较大的影响.文章从胞外聚合物的性能、金属离子对胞外聚合物的影响、胞外聚合物的提取方法以及变化特征等方面阐述EPS的研究进展.     

高铁酸钾溶胞联合A/O-MBR工艺污泥减量研究

结合高铁酸钾(K_2FeO_4)溶胞技术和A/O-MBR工艺在污泥减量方面的优势,在掌握K_2FeO_4溶胞对污泥性质影响基础上,将K_2FeO_4溶胞技术应用于A/O-MBR工艺,构建A/O-MBR+K_2FeO_4溶胞组合工艺.采用序批式实验研究K_2FeO_4溶胞对污泥性质影响,结果表明,溶胞后污泥固相SS和VSS降低,液相中COD、TN和TP质量浓度明显升高.平行运行对照A/O-MBR工艺和A/O-MBR+K_2FeO_4溶胞组合工艺,结果表明,A/O-MBR+K_2FeO_4溶胞组合工艺的污泥表观产率为0. 10 kg SS/kg CODremoved,明显低于对照A/O-MBR工艺(0. 22kgSS/kg CODremoved),产生显著的污泥减量效果(54.5%);同时,与对照A/O-MBR工艺相比,A/O-MBR+K_2FeO_4溶胞组合工艺的COD去除效果变化不大,TN去除率升高,TP去除率降低.     

新型脂肪酶LipB52催化生物柴油

一种来源于荧光假单胞菌的新型脂肪酶基因lipB52在大肠杆菌BL21(DE3)中获得表达,并且利用Ni-NTA亲和柱时脂肪酶LipB52进行纯化.采用固定化脂肪酶LipB52催化大豆油与甲醇的转酯反应生产生物柴油.实验考察了温度、底物摩尔比、酶用量、有机溶剂、酶的种类以及油的类型对于反应的影响,结果表明:转酯反应的最佳反应条件为:m(酶):m(油)=20:80,n(油):n(甲醇)=1:4、正庚烷作为溶剂、反应温度为30℃,在此条件下脂肪酶LipB52表现出很高的催化活性,反应40 h后甲酯的产率高达92%.     

影响燃煤还原气体生成特性的因素

利用傅里叶红外气体分析设备,在自制的固定床反应器上对能够显著影响再燃煤还原气体生成特性的因素进行了实验研究.结果表明,神木煤在N2和CO2气氛下受热生成的还原气体主要有CO、CH4和HCN4·CO2气氛有利于原料煤中的C更多地转化为CO,CH4在N2和CO2气氛下的生成特性及产率相近.O2对神木煤的CO、CH4及HCN的生成特性影响很大,氧的存在降低了CO开始形成的温度及产率,也降低了CH4的生成温度和产率.O2使得HCN开始生成的温度大幅度降低,当w(O2)为6%时HCN的产率明显增加,同时O2的存在还增加了NO的产率.无论是在N2气氛还是在CO2气氛下,快速升温时CH4的产率均高于程序升温时的值,但CO的产率均小于程序升温时的值.升温速率对HCN的影响与煤种有关,除TC煤外,快速升温时HCN的产率均比程序升温时低.     

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.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the