云芝漆酶理化性质及动力学研究

主要研究pH值、金属离子、温度对云芝漆酶活性和稳定性的影响,以及该酶底物浓度效应和Km值测定.实验结果表明:Cu2+、Co2+对漆酶有激活作用,而Ag+则有抑制作用;该酶最适pH为4.8,在pH4~4.8表现出较强的稳定性;最适反应温度为40℃,低于50℃时有较好的热稳定性;Km值为4.2×10-3mol/L.     

葡萄糖酶电极的制备和测试

以自制的铂电极为基础,制备了葡萄糖酶电极,并测试了淀粉-糖化酶水解液中的葡萄糖,测定的范围为2×10~(-6)～5×10~(-3)mol/L。     

两种分子形式尿激酶直接水解苄氧羰-L-酪氨酸P-硝基酚酯(CTN)的化学动力学

(1) 以纤维蛋白溶酶原(PG)为底物,H—uk的Km值为L—uk的一半。但以CTN为底物时,H—uk和L—uk的Km值很接近,分别为5×10~(-4)M和4×10~(-4)M。 (2) 在PH7.5—9.0范围内,改变氢离子浓度只影响两种尿激酶水解CTN的最大反应速度V,而Km保持不变。由此断定k_(-1)>>k_2。Km是平衡常数的倒数。以pH对logV作图,求得H—uk和L—uk活性中心可解离基团的PK很接近,分别为7.65和7.85。 (3) ∈—氨基已酸(E-ACA)对两种尿激酶都呈现典型的竞争性抑制作用。EACA对H—uk的Ki为0.8×10~(-2)M,对L—uk的Ki为1.5×10~(-1)M。来源不同的天然胰蛋白酶抑制剂对两种尿激酶都不抑制。 (4) 观察了温度对K_m和k_2的影响,计算了平衡反应和活化过程的各种热力学常数。 (5) 从所得动力学和热力学结果推测,两种分子形式尿激酶的活性中心性质相同,但二者的构象却很不相同,H—uk的结构更有利于进行反应,由此推测H—uk是尿激酶的天然形式,L—uk是前者的降解产物。     

纤维素酶固定化研究

利用固态发酵法从瑞氏木霉QM9414发酵液中提取纤维素粗酶液,然后将其固定在壳聚糖上,测定粗酶液的酶活力,固定化酶与粗酶的最适pH,最适温度和Km值.结果表明,粗酶液的蛋白质含量为33.33 ug/mL,酶活力为120 IU/mL.固定化酶的最适温度为60℃而粗酶液为50℃,粗酶液的最适pH=5,固定化酶的最适pH=4,固定化酶的Km值3.592 01×10-2,粗酶液的Km值为4.076 04×10-2,表明固定化酶的很多性质均优于游离酶液.     

文昌鱼酸性磷酸酯酶的化学修饰

用DEAE-纤维素(DE-22)并改进酶的提纯方法,聚丙烯酰胺凝胶电泳为单一蛋白区带的酶制剂比活力为359μM/mg(E)/min(Npp为底物)·用凝胶过滤法测得该酶分子量为58600,氨基酸组成有20种,共467个氨基酸残基。10~(-4)M pCMB使酶活力丧失98％;1×10~(-3)M PMSP该酶活力丧失96％,2×10~(-4)M NBS以及1×10~(-2)M BrAc酶活力均丧失90％·酶修饰失活呈一级反应,修饰过的酶紫外280nm吸收峰消失·初步判断文昌鱼AcPase分子上的Cys,Trp,His,Ser等氨基酸残基可能是酶的活力必需基团。     

Debaryomyces sp.甘油激酶基本动力学性质研究

通过平板初筛和摇瓶复筛,从105株菌中筛得一株甘油激酶的高产菌株,并研究了其所产甘油激酶的动力学性质.研究结果表明:在MES系统中,甘油激酶有较好的酸碱稳定性,pH稳定范围为5.5～10.5;最适pH和最适温度分别为pH 8.0和50℃,该酶催化甘油的米氏常数(Km)为3.5×10-5mol/L,催化ATP的Km为4.46×10-4mol/L.同时对一些金属离子和有机化合物对酶活性的影响也进行了研究.     

蒙脱石K-10吸附固定糖化酶研究

蒙脱石是一种优良的吸附剂,采用吸附法将其作为固定化糖化酶的载体研究固定化糖化酶的性质,结果表明:每克固定化酶的活力3 442 U;固定化酶的最适pH值是4.8,比游离酶的最适pH值增加了0.2;固定化酶反应的最适温度是60 ℃,比游离酶升高了5 ℃;固定化酶的半衰期为12 d;固定化酶的Km=14.3 g/L,为游离酶的1.47倍.     

瑞氏木霉β-内切葡聚糖酶的纯化及其部分酶学性质研究

 利用盐析、SephadexG-75和DEAE-SephadexA50层析,从瑞氏木霉TrichodermareeseiQM9414发酵液中纯化了2个具有β-内切葡聚糖酶活性的组分Eg1和Eg2,分子质量分别为65.47ku和57.04ku.其最适温度分别为50℃和55℃,最适pH分别为4.8和5.0,米氏常数Km分别为3.76×10^-2g/L和4.20×10^-2g/L.根据其酶学性质,这是一类不同于已有的β-内切葡聚糖酶,为瑞氏木霉T.reeseiQM9414所产β-内切葡聚糖酶的进一步研究奠定了基础.     

文昌鱼碱性磷酸酶的热力学特征初步研究

从厦门文昌鱼中,获得提纯200倍的经聚丙稀酰胺凝胶电泳鉴定为均一的碱性磷酸酶。从热力学及热失活动力学角度初步探索了改变酶的结构对酶活力的影响。实验结果初步表明:在pH10.1时酶作用于对硝基苯磷酸钠的K_m值随反应温度的增高(25、30、35℃)而相应的增大(分别为5.81×10~(-4),8.09×10~(-4)及9.30×10~(-4)M)。其一级反应速度常数k_p分别为1.88×10~(-4),2.25×10~(-4)及2.31×10~(-4)秒~(-1)。天然第一态与变性第二态酶催化反应的活化能Ea分别为10.09 kcal/mole及4.51 kcal/mole,△H_1为24.09 kcal/mole及△s_1为74.44e.u.。在pH10.1时,酶促反应呈现一个严格的转化温度(32-35℃)。据活力计算,自然酶变性酶的二态可逆变性反应的热力学参数△S之值,认为酶局部变性,酶分子开始部分伸展,可能涉及三个氢键被破坏,但未涉及酶的总体结构。     

中国黑白花优良种公牛精子透明质酸酶的分离纯化及部分性质研究

中国黑白花优良种公牛精子透明质酸酶经硫酸铵分级沉淀和 Sephadex 柱层析分离纯化,得到一个电泳纯品,活力纯化40倍.用 sephadexG-150凝胶过滤和 SDS—聚丙烯酰胺凝胶电泳测得分子量为65000.该酶的最适 pH 为3.5～4.5,最适温度为37℃～45℃,在室温下较稳定,用 Limeweaver-Burk 作图法求得 Km 值为6.06×10~(-4)mol/L.     

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.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to