大鼠胰腺β细胞内葡萄糖钙信号调控机制

用fura-2显微荧光法测量细胞内自由钙浓度[Ca2+]i,在单个大鼠胰腺β细胞上探讨了葡萄糖诱发的[Ca2+]i初期下降相(GIDP)、钙振荡和钙库释放的影响因素.实验中发现,非刺激浓度的葡萄糖(5 mmol/L)仍可导致β细胞特有的GIDP.GIDP与去极化无关,也不受外钙的影响,但能被内质网钙泵抑制剂thapsigargin抑制,提示此过程可能缘于钙库对胞浆Ca2+的摄取.在胞内钙振荡过程中移去胞外液中的Ca2+,振荡会逐渐停止;若施加thapsigargin,钙振荡仍能继续维持,说明钙振荡主要缘于外钙内流,钙库在钙振荡维持中的作用不大.无外钙条件下,葡萄糖诱导的钙库释放能被钠通道阻断剂TTX所抑制,而高钾对钙库的释放作用却不受TTX的影响,这提示膜去极化可以直接诱导钙库释放.因此,细胞膜去极化、外钙内流、胞内钙库的摄取和释放共同协调着β细胞内的Ca2+平衡.     

不同机制参与黄体酮扩张兔血管作用

用离体血管条灌流实验方法 ,观察黄体酮对血管条去甲肾上腺素 (NA) ,Ca Cl2 ,KCl反应的影响 ,并观察给予 L- NNA、甲烯蓝 (MB)、吲哚美辛、普萘洛尔及去除内皮细胞后 ,黄体酮扩张血管作用的变化 .结果发现 :黄体酮 10 -4 mol· L-1及 10 -5mol· L-1分别使 NA和无 Ca2 +高 K+Krebs液中 Ca Cl2 量效曲线明显右移 ,最大反应压低 ,PD2 ′分别为 3.51和 4 .56 .黄体酮 2 .5× 10 -4mol· L-1使无 Ca2 + 液中 NA10 -6mol· L-1收缩血管作用明显减弱 (p <0 .0 0 1) ,但不影响 Ca Cl210 mmol· L-1引起的收缩 .L - NNA,MB及去除内皮可明显减弱黄体酮扩张 KCl 4 0 mmol· L-1的收缩血管作用 ,但吲哚美辛和普萘洛尔无明显影响 .结果表明 :黄体酮可通过受体操纵 Ca2 + 通道抑制 IP3 途径引起的内 Ca2 + 释放 ,也可通过电压依赖式 Ca2 + 通道抑制外 Ca2 + 内流 ,使血管条舒张 ,其作用有内皮依赖性 ,部分与 NO和 c GMP有关     

地西泮对大鼠脑突触体内Ca2+水平和Ca2+, Mg2+-ATP酶活性的作用

用Quin 2法测得大鼠脑突触体内静息游离Ca2+浓度([Ca2+]i)为85±13μmol/g protein.地西泮0.1,1和10 mmol/L对静息突触体[Ca2+]i无明显影响,但能以剂量依赖方式增高65 mmol/LKCl所致突触体[Ca2+]i升高,从105±23μmol/g protein分别达到185±28,267±49和291±48μmol/gprotein.地西泮1和10 mmol/L分别使突触体Ca2+,Mg2+-ATP酶活性降低28.7%和42.5%;使Mg2+-ATP酶活性分别降低12.6%和32.8%,提示地西泮可能是通过抑制钙调素,进而抑制Ca2+,Mg2+-ATP酶活性,使突触体[Ca2+]1升高,促进神经末梢释放递质.     

Protective effect of curcumin against gp120 V3 loop-induced neuronal synaptosomes insult in rat hippocampus

目的:探讨姜黄素对gp120 V3环所致大鼠海马神经元突触体损伤的保护作用及其机制.方法:采用无血清培养法培养大鼠海马神经元,MTT法确定姜黄素神经元保护性剂量和gp120 V3环神经元毒性剂量.应用Fura-2/AM钙离子探针检测各组突触体内Ca2+浓度,透射电镜观察突触体形态改变,体视学方法分析线粒体体密度Vvm、线粒体数密度Nm、线粒体的平均体积Vm.结果:浓度为1μmol/L的姜黄素在48h内对细胞的存活率无明显影响,浓度为2 μmol/L的姜黄素作用12 b以及更高浓度,显著抑制细胞存活率(P＜0.05);gp120 V3环对大鼠海马神经元的毒性具有时间依赖性,其中各浓度gp120 V3环在作用2～8h范围内对细胞存活率无明显影响,在作用12 h后细胞存活率显著降低(P＜0.05),浓度为1 nmol/L的gp120 V3环作用24h后细胞存活率降低为(85.3±2.8)％,因此采用浓度1 nmol/L gp120 V3环观察其对大鼠海马神经元突触体损伤效应.与对照组相比,gp120 V3环孵育的突触体内线粒体明显肿胀,Vom、Nm、Vm增大,Ca2浓度升高(P＜0.01);与模型组相比,姜黄素+gp120 V3环组与尼莫地平+ gp120 V3环组V(o)m、Nm、Vm明显减小(P＜0.01),Ca2+浓度降低(P＜0.05),差异有统计学意义.姜黄素或尼莫地平单独作用于突触体对其形态及Ca2+浓度无影响.结论:姜黄素对大鼠海马神经元的药理作用具有浓度依赖性;gp120 V3环对大鼠海马神经元的损伤具有时间依赖性.姜黄素可减轻gp120 V3环导致的神经元突触体损伤,减小gp120V3环引起的突触体内增大的线粒体V(om)、Nm、Vm,其机制可能抑制gp120 V3环过度激活的Ca2+通道,从而降低细胞内升高的Ca2+浓度.     

低频调制磁场对脑电节律的影响机理

神经细胞Ca2 内流及脑内5 HT、NE、DA等神经递质的变化影响了神经细胞放电速率,从而影响脑电节律.为揭示低频调制磁场对脑电节律产生影响的微观作用机理,检测了Wistar大鼠脑内神经递质的释放,电镜下观察了其神经突触形态的变化.实验结果显示,低频调制磁场作用引起大鼠脑内去甲肾上腺素(NE)、多巴胺(DA)、5 羟色胺(5 HT)释放显著增加(P<0.05),并观察到大鼠神经细胞内钙颗粒及释放神经递质的突触小泡数明显增加,提示低频调制磁场对人脑电节律的影响机理是其改变了Ca2 内流及脑内神经递质的释放量.     

15 － KETE 对大鼠肺动脉平滑肌细胞钙离子浓度的影响

摘要: 目的探讨15-KETE 对大鼠肺动脉平滑肌细胞内Ca2 + 的作用及其来源。方法以酶法( 胶原酶Ⅰ型和弹性 酶) 分离培养原代大鼠肺动脉平滑肌细胞,将细胞稀释所需密度( 2 × 105 个/mL) ,加样于6 孔板中的盖玻片上,放 入37℃孵箱中培养12 h,细胞贴壁后,取出6 孔板中的盖玻片,放入特制的小槽内,D-Hanks 液冲洗细胞3 次,加入 1 × 10 － 5mol /L 的Flou-3 /AM,置37℃孵箱中避光孵育约30 min,用D-Hanks 液洗去细胞外残留染料,应用激光扫描 共聚焦显微镜技术,测定了15-KETE 对大鼠肺动脉平滑肌细胞游离钙离子浓度的影响。结果1) 15-KETE ( 1 × 10 － 8-1 × 10 － 6 ) mol /L 可依赖性引起肺动脉平滑肌细胞内钙离子浓度( ［Ca2 +］i) 增加; 2) 1 × 10 － 6 mol /L 维拉米( L-型钙离子通道阻断剂) 和无钙离子细胞外液显著阻抑了1 × 10 － 6 mol /L 15-KETE 引起肺动脉平滑肌［Ca2 +］i 增 加。结论15-KETE 可引起大鼠肺动脉平滑肌［Ca2 +］i 增加,并且此钙来源于细胞外液钙离子。     

大黄酸对IL-2诱发T淋巴细胞增殖和细胞[Ca2+]i变化的作用

研究大黄酸对IL-2引起大鼠T淋巴细胞增殖和细胞内[Ca2+]i变化的影响.采用MTT法检测细胞增殖,用单细胞钙成像系统记录胞内游离Ca2+浓度([Ca2+]i).结果表明,大黄酸对IL-2引起的细胞增殖有显著抑制作用,且抑制效果与剂量有关;IL-2引起[Ca2+]i升高,并持续维持高[Ca2+]i水平,[Ca2+]i升高的机制包括胞内Ca2+释放和胞外Ca2+内流;大黄酸显著抑制IL-2引起的[Ca2+]i升高.结果提示大黄酸可抑制T淋巴细胞增殖,作用机制可能与抑制细胞内[Ca2+]i升高相关.     

Ca^2＋和Mg^2＋对54kD钙结合蛋白荧光强度影响的研究

猪血小板 5 4kD钙结合蛋白 (calciumbindingprotein ,CaBP)是一个等电点为 5 .5的弱酸性蛋白质 ,其N 末端为丙氨酸 (Ala) ,且未经修饰 ,在 2 80nm波长的紫外光激发下 ,该蛋白质具有λmax为 335nm的内源荧光发射光谱 ,Ca2 +、Mg2 +均能减弱其发射荧光的强度 ,但对其λmax没有影响 .通过测定不同Ca2 +浓度下荧光强度的变化 ,可计算出在无Mg2 +存在时 ,该蛋白质的钙结合常数为 3.2× 10 - 8mol/L ,而在Mg2 +饱和条件下 ,钙结合常数为 7.4× 10 - 6 mol/L .乙醇亦不影响该蛋白质荧光的λmax,而对其荧光强度的影响则依赖于是否与钙结合 .未与Ca2 +结合时 ,乙醇浓度的增加导致荧光强度增强 ,与Ca2 +结合后 ,在低浓度乙醇溶液中 ,蛋白荧光强度减小 ,至乙醇浓度大于 16 .6 %后 ,其荧光强度逐渐增强 ,在 35 %乙醇溶液中 5 4kDCaBP对Ca2 +不敏感     

细胞内圆柱形空间钙波的Fire-Diffuse-Fire模型

考察Fire-Diffuse-Fire模型在圆柱区域内钙波的传播情况.通过求解扩散方程,得到了圆柱区域内Ca2+浓度的解析表达式.分析证明了钙波的存在性、稳定性依赖于半径和Ca2+泵率,产生钙释放的阈值在有限区间内随半径增大而增大.此结果有助于了解细胞内的内质网以及Ca2+泵在细胞Ca2+动力学上的作用.     

丙烯酸钙对水泥水化进程的影响

采用红外光谱测试、差热-热重(DTA-TG)分析和X射线衍射(XRD)测试等手段对水泥综合改性效果进行分析,研究丙烯酸钙对水泥水化热历程的影响。结果表明:丙烯酸钙促进早期钙矾石(AFt)的生成,促进硅酸三钙(C3S)的不断水解及水化期的放热速率;抑制AFt向单硫型水化硫铝酸钙(AFm)的转变,影响Ca(OH)2的成核和析出,导致3～24 h内Ca(OH)2的生成量减少;水化后期提高水泥浆体分散性和液相中Ca2+浓度,水化更充分。     

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.     

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.     

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。     

A computer generator for randomly layered structures

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

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.     

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.     

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。     

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

正~~     

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     

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