脱脂沙苑子乙醇提取物的体外抗氧化活性研究

通过测定脱脂沙苑子乙醇提取物(ESA)对1,1-二苯基-2-苦苯肼自由基(DPPH·)、超氧阴离子自由基(O-·2)和羟基自由基(·OH)的清除能力、对Fe2 诱导的脂质过氧化反应的抑制作用、还原力和总抗氧化力,评价ESA的体外抗氧化活性,并与公认的抗氧化剂维生素C作了对照.结果表明,ESA有一定的DPPH·清除能力(IC50=419.1μg/mL)、较强的超氧阴离子清除能力(IC50=117.9μg/mL)和羟基自由基清除能力(IC50=224.4μg/mL),能有效的抑制脂质过氧化(IC50=1.70 mg/mL),有良好的总抗氧化力,说明沙苑子具有明显的抗氧化活性.     

南瓜醇提物对DNA损伤的保护及体外抗氧化研究

采用琼脂糖凝胶电泳技术,检测南瓜醇提物(ethanol extract from pumpkin,EEP)对因紫外线照射过氧化氢(H2O2)产生羟自由基(·OH)而引发质粒pUCl8 DNA链断裂的保护作用.用化学体系模拟法测定EEP对1,1-二苯基-2-苦苯肼自由基(DPPH·)和·OH的清除能力;将Fe3 还原成Fe2 的能力以及在β-胡萝卜素/亚油酸自氧化体系中的总抗氧化能力.结果表明,EEP在浓度为12.0 mg/mL时能有效保护DNA的氧化损伤,对DPPH·和·OH的清除能力较强,IC50值分别为18.8 mg/mL和44.9 μg/mL时有显著的还原力和总抗氧化力.EEP具有较强的体外抗氧化活性.     

淫羊藿苷与脱水淫羊藿素的体外抗氧化研究

为研究淫羊藿苷和脱水淫羊藿素的体外抗氧化活性,分别测定了两者对1,1-二苯基-2-苦苯肼自由基(DPPH.)、超氧阴离子自由基(O2.)、羟自由基(OH.)的清除能力、对脂质过氧化的抑制能力、还原力以及总抗氧化能力.实验结果表明,淫羊藿苷具有很强的清除DPPH.、超氧阴离子自由基,还原力和总抗氧化的能力,有较强的清除OH.的能力,且均呈剂量依赖性.脱水淫羊藿素对DPPH.的清除能力很强,对OH.、超氧阴离子和脂质过氧化有较强的清除和抑制作用,表明淫羊藿苷和脱水淫羊藿素具有明显的抗氧化活性.     

玉竹多糖的抗氧化作用研究

为研究玉竹多糖的体外抗氧化活性和清除自由基作用,采用体外化学体系研究玉竹多糖对超氧阴离子(O-2·)、羟自由基(·OH)、1,1-二苯基-2苦苯肼自由基(DPPH·)和过氧化氢(H2O2)的清除能力。结果表明:玉竹多糖对超氧阴离子(O-2·)、过氧化氢(H2O2)和1,1-二苯基-2-苦苯肼自由基(DPPH·)具有较强的清除能力,其EC50值分别为0.38 mg/mL(Vc为0.09 mg/mL)、0.65 mg/mL(Vc为0.70 mg/mL)和0.43 mg/mL(Vc为0.06 mg/mL);但对羟自由基(·OH)的清除能力较弱,其EC50值为14.7 mg/mL(Vc为0.34 mg/mL)。玉竹多糖具有较好的体外抗氧化活性。     

葛花总黄酮的抗氧化作用研究

为研究葛花总黄酮的体外抗氧化作用,以70%乙醇为溶剂,微波方法提取葛花中的总黄酮,用比色法测定其含量为4.72%;通过还原能力的测定、Fenton反应体系、DPPH法以及邻苯酚自氧化体系等评价葛花总黄酮体外抗氧化能力.结果显示,葛花总黄酮在还原力测定以及对三种自由基的清除上,表现出了不同程度的抗氧化能力.对O2-.和DPPH.及.OH 3种自由基具有明显的的清除作用,其EC50分别为:0.095mg/ml、0.114mg/ml、0.700mg/ml.葛花总黄酮具有较强的还原力,在清除自由基方面其清除率与其浓度存在着明显的量效关系.     

高粱红色素的体外抗氧化研究

为研究高粱红色素的体外抗氧化活性,测定了高粱红色素对1,1-二苯基-2-苦苯肼自由基(DPPH·)、超氧自由基(O2-·)和羟自由基(·OH)的清除能力,还原力,对Fe2+诱导的脂质过氧化反应和β-胡萝卜素/亚油酸自氧化体系的抑制作用.结果表明,高粱红色素对DPPH·有较好的清除能力,能很好地清除O2-·和·OH,对Fe2+诱导的脂质过氧化有一定的抑制作用,对β-胡萝卜素/亚油酸自氧化体系有明显的抑制作用,可见高粱红色素具有良好的抗氧化能力,除作为色素使用外,也可作为抗氧化剂使用.     

海藻铁钉菜抗氧化活性部位研究

以DPPH自由基清除能力、TEAC值与主要化学成分含量为指标,从福建省围头海域的10种海藻中筛选出总酚含量较高、抗氧化活性较强的海藻及其抗氧化活性部位.进一步对该海藻的抗氧化活性部位进行DPPH自由基清除能力、还原力与总抗氧化能力的测定,初步分析金属离子对其抗氧化活性的影响.结果表明:10种海藻中,铁钉菜甲醇提取物具有较高含量的多酚、TEAC值与较强的DPPH自由基清除能力,乙酸乙酯部位是其主要的抗氧化活性部位.铁钉菜乙酸乙酯部位对DPPH自由基清除的半效应浓度EC_(50)为0.17 mg/m L,小于BHT EC_(50)0.23 mg/m L;还原力的EC_(50)为0.30 mg/m L,远远小于维生素C EC_(50)0.91mg/m L;总抗氧化能力约为13.16 U/mg.金属离子对铁钉菜乙酸乙酯部位的DPPH自由基清除的影响表现为K~+、Cu~(2+)、Zn~(2+)、Ca~(2+)、Fe~(3+)等的增效作用与Na~+、Mn~(2+)、Mg~(2+)等的降效作用.     

叶下珠提取物对酪氨酸酶的抑制和抗氧化作用

叶下珠为传统民间草药,具有平肝清热、利水解毒之功效.以叶下珠为研究对象,经乙醇提取,溶剂极性递增分离法制备获得叶下珠植物成分,测定了叶下珠植物对酪氨酸酶的抑制作用,以及运用1,1-二苯基-2-苦苯肼(DPPH)自由基法检测其清除自由基的能力.结果表明:叶下珠乙酸乙酯提取物和正丁醇提取物对酪氨酸酶二酚酶有较强抑制作用,IC50值分别达到0.26和0.49 mg/mL,动力学研究表明:叶下珠乙酸乙酯提取物和正丁醇提取物对酪氨酸酶抑制作用均是可逆的,其抑制类型为混合型抑制作用;叶下珠乙酸乙酯提取物和正丁醇提取物对DPPH自由基具有一定的清除作用,在较低的浓度下有较高的清除效果,IC50值分别为0.012和0.008 mg/mL,说明叶下珠植物具有开发成天然酪氨酸酶抑制剂和抗氧化剂的潜力.     

新疆产细虫草菌醇提物抗氧化及抗肺癌活性研究

利用DPPH自由基清除能力与总还原能力分析,对新疆产细虫草发酵菌丝体的菌醇提物(OGPDC)的抗氧化能力进行测定.MTT分析OGPDC对肺癌A549细胞增殖的抑制作用.抗氧化结果表明OGPDC具有较好的清除DPPH自由基及总还原能力,且清除自由基和总还原能力随着醇提物浓度的升高,逐渐增强,清除DPPH自由基的IC50值为1.952 mg/mL;MTT结果显示OGPDC对肺癌A549细胞增殖有一定的抑制作用,随着浓度提高而增强,处理48 h时药物的IC50值为10.87 μg/mL.另外,利用用流式细胞仪检测OGPDC作用48 h后肺癌A549细胞周期变化及凋亡率,其总凋亡率高于仅加培养液的对照组,最高总凋亡率为34.77%,使A549细胞周期阻滞在G0/G1期.结果表明新疆产细虫草菌醇提物(OGPDC)在一定的浓度范围内具有抗氧化及抗癌活性,暗示新疆产细虫草发酵菌丝体具有重要的开发利用价值.     

黄山贡菊总黄酮体外抗氧化活性研究

以超声波辅助法提取黄山贡菊的总黄酮,以还原力、金属离子螯合性和对DPPH自由基、亚硝酸钠的清除能力为指标评价黄山贡菊总黄酮的抗氧化活性.结果表明,总黄酮还原力的IC50为0.171mg/mL,金属离子螯合性的IC50为1.529mg/mL,总黄酮对DPPH.和亚硝酸钠清除作用的IC50分别为0.323、0.700mg/mL.黄山贡菊总黄酮具有较强体外抗氧化活性,活性与浓度存在一定的量效关系.     

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…     

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     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.