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1.
以氯胺T为氧化剂制备了~(125)Ⅰ一标记尖吻蝮蛇毒NAD糖苷水解酶,将~(125)Ⅰ—NAD糖苷水解酶注入小鼠尾静脉,观察小鼠体内各脏器及血液中不同时间的分布情况,发现~(125)Ⅰ—NAD 糖苷水解酶住血液和大多数组织中放射活性在3小时内较高,3小时后下降较快,12小时后稳定,48小时随尿、粪便排泄完.以3小时测量各组织放射性脉冲数/分钟相加合计算(相对百分数),血液27.8%>胃20.8%>肾16.6%>肺12.2%>脾7.0%>肝5.2%>小肠4.9%>心4.6%>脑0.8%.  相似文献   

2.
本文将巯基乙醇还原法与苯甲脒-Sepharose 4B亲和层析法相结合,于亲和柱上裂解了尿激酶蛋白的A、B链,制备出高纯度的尿激酶B链,活力回收达89.3%。样品经SDS-聚丙烯酰胺凝胶电泳检测为均一单带,测得分子量为32KD,比活为214×10~3iu/mg蛋白,活性的最适pH为8.0。在体外测活系统中,尿激酶B链有类似于尿激酶的性质。若以纤维蛋白溶酶原为底物,测得B链的Km值为尿激酶的3.2倍。由此推测,天然形成的尿激酶结构更有利于纤溶反应。  相似文献   

3.
以氨基化二氧化硅为载体, 戊二醛为交联剂, 采用共价交联法制备固定化纤维素酶, 最佳条件为交联剂浓度4% (体积比), 交联时间60分钟, 给酶量35 U/g载体, 固定化反应时间5小时。所得固定化酶对pH和温度的敏感性降低, 时间稳定性和热稳定性均优于游离酶。热动力学研究表明, 固定酶的失活活化能(Ed)、失活焓(ΔH*)和失活自由能(ΔG*)均高于自由酶, 固定化减小酶失活反应速率, 降低酶失活反应趋势。  相似文献   

4.
尿激酶英文名Urokinase(UK),碱性蛋白酶,等电点PH8—9,分子量31300和54700两种,活性中心由丝氨酸和组氨酸组成。在体内,尿激酶作用于血纤维蛋白溶酶原;医学上,用于溶解血栓。酶可从尿中排出,每毫升尿中含量约5国际单位。制备方法: 1.收集男性尿。(PH小于7,必要时加0.8%苯酚防腐,天热时应在4小时内制备  相似文献   

5.
本文对谷氨酸生产茵AS_1.299谷氨酸脱氢酶的专一性辅酶、热稳定性、动力学参数和发酵过程中的活力变化进行的研究表明,该酶以辅酶Ⅱ为其专一性辅酶;于50℃保温10分钟保留活力约为18%,而在60℃保温同样时间几乎完全失活;对L-谷氨酸和辅酶Ⅱ的动力学参数分别为55.6和0.139毫克分子;在发酵过程中,前期酶活力逐渐上升,在24小时左右酶活力最高,其后酶活力逐渐下降。  相似文献   

6.
本文研究了在乙醇-水介质体系中,放射性碘标记玫瑰红钠盐的反应条件影响,得到了最佳的标记条件.在 pH=2.4,C_2H_5OH/H_2O=5—7,KIO_3/攻瑰红=0.1,反应温度80—100℃,反应时问15—20分钟时,标记率在95%以上,游离碘在3%以下.经鉴定,产品质量稳定,在室温放置一个月.~(125)I-玫瑰红含量为93%,基本上能满足临床指标.  相似文献   

7.
本文报导了同位素标记化合物14—125碘—苯并—15—冠—5在小白鼠体内的代谢动态,发现药物经腹腔注入小白鼠体内后,能被迅速吸收和排除,注入2小时后为药物的吸收高峰,主要分布于肾脏、肝脏,8小时后药物由尿、粪排除52.8%,48小时累积排除量为92%,初步可以认为14—125碘—苯并—冠—5在动物体内存留时间短,蓄积性小。  相似文献   

8.
本文提供了以732阳离子交换树脂作为尿激酶(UK)吸附剂,从人尿中分离提纯粗品UK的新方法。其方法是:将新鲜男性尿调到pH值9.0,弃去沉淀。上清液调到pH值5.3—5.5,然后加入732树脂,搅拌吸附1.5 小时,被吸附的UK用2%氨水洗脱。洗脱液加固体硫酸铵,使其饱和度达65%,并调pH至8.6,收集沉淀。收率可达70—80%,比活为600—800CTA单位/毫克蛋白。以732树脂做为尿激酶吸附剂,比724树脂收率高10%左右。  相似文献   

9.
本文报导了同位素标记化合物~14—~(125)碘—苯并—15—冠—5在小白鼠体内的代谢动态,发现药物经腹腔注入小白鼠体内后,能被迅速吸收和排除,注入2小时后为药物的吸收高峰,主要分布于肾脏、肝脏,8小时后药物由尿、粪排除52.8%,48小时累积排除量为92%,初步可以认为~14—~(125)碘—苯并—15—冠—5在动物体内存留时间短,蓄积性小。  相似文献   

10.
枯草芽孢杆菌478是为生皮脱毛选育的一株中性蛋白酶产生茵。500 ml 摇瓶,装量50 ml 培养基,接种一小铲,31℃摇床培养40小时,产酶为5502 u/ml。BF—12—Ⅰ型罐发酵28小时,31℃产酶为5795 u/ml。酶的酪蛋白水解最适 PH 为7.0,活性范围为 PH 6.5~7.5,此间热稳定性较好,40℃两小时失活为12%。酪蛋白水解的最适温度为40~50℃。Fe ~(++)Hg~(++)与 Cu 对酶有抑制作用,Ca~(++)与 Mg~(++)则有激活作用。聚丙烯酰胺凝胶电泳分析得到9条带。国内外一直沿用的硫化碱脱毛工艺对环境污染严重。酶法脱毛则是解决污染问题的可行途径。半个世纪以来人们对此作了积极的研究。然而,可用的产酶株仍是屈指可数,脱毛工艺的革新受到很大限制。为了推进酶法脱毛工艺向前发展,我们选育了脱毛效果较好的枯草芽孢杆菌478中性蛋白酶产生株。本文对该茵的发酵及其产生的中性蛋白酶的一些基木特性作一报导。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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。  相似文献   

16.
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.  相似文献   

17.
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。  相似文献   

18.
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.  相似文献   

19.
20.
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  相似文献   

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