End-column amperometric detection of 5-fluorouracil by capillary zone electrophoresis with a carbon fiber microelectrode

A rapid and sensitive detection method for the determination of 5-fluorouracil(5-FU) in real samples such as human urine and bovine serum albumin (BSA) was described. A carbon fiber microdisk electrode was used to perform end-column amperometric detection in capillary zone electrophoresis. The detection limit was as low as 2.5x10(-7) M and the wider linear range for the concentration was between 5x10(-6) and 1x10(-4) M with a correlation coefficient of 0.995.

毛细管区带电泳柱端安培检测抗癌药物巯嘌吟

报道了一种高效快速检测抗癌药物巯嘌呤的方法——毛细管区带电泳柱端安培检测.考察了巯嘌呤的电化学行为.在最佳操作条件下,获得此药物的检测限为1×10~(-7)mol/L;线性范围为5×10~(-4)～5×10~(-6)mol/L;相关系数为0.995,重现性良好.并用该法检测了人尿样及牛血清蛋白中的巯嘌呤.

PHYSICAL AGING OF HIGH-PERFORMANCE THERMOPLASTICS - ENTHALPY RELAXATION IN PEK-C AND PES-C

The developments of physical aging in phenolphthalein poly(aryl-ether-ketone) (PEK-C) and poly(aryl-ether-sulfone) (PES-C) with time at two aging temperatures up to 20 K below their respective glass transition temperatures (T-g = 495 and 520 K) have been studied using differential scanning calorimetry (DSC). Substantial relaxation within the aging course of several hours were observed by detecting T-g decreasing during physical aging process at the two aging temperatures. The relaxation processes of both polymers are extremely nonlinear and self-retarding. The time dependencies of their enthalpies during the initial stages of annealing were approximately modeled using the Narayanaswamy-Tool model. The structure relaxation parameters obtained from this fitting were used to predict the possibility of physical aging occurring at their respective using temperatures. (C) 1995 John Wiley and Sons, Inc.

高纯氧化钪中痕量稀土元素的电感耦合等离子体原子发射光谱分析和稀土元素间的光谱干扰及其校正

本文提出了用 ICP-AES 直接同时测定高纯氧化钪中15个痕量稀士元素的新方法。用PGS-2光栅光谱仪,Plasma Therm ICP-5000D 光源系统,乙醇预去溶进样方式,直接同时测定纯度为99.995%的高纯氧化钪中15个痕量稀土杂质元素,并讨论了稀土元素间的干扰及某些元素的光谱干扰的校正。当样品溶液中稀土总浓度为5mg/ml:时,测定下限为镧、钆、钬和铥0.0002%,镨、钕、铽和镥0.0004%,铕、镝、铒和钇0.0001%、镱0.00004%,铈和钐0.001%。其相对标准偏差为1.7～8.2%。

A novel tumor necrosis factor ligand superfamily member (CsTL) from Ciona savignyi: Molecular identification and expression analysis

A novel invertebrate TNF ligand was identified and characterized in Ciona savignyi. The CsTL cDNA consisted of 995 nucleotides and encoded 281 amino acids. A conserved TNF family signature and several motifs of TNF ligand superfamily were identified in deduced amino acid sequence of CsTL. Phylogenetic analysis grouped CsTL, CiTNF (predicted TNF ligand superfamily homolog in Ciona intestinalis) and urchin TL1A with their own cluster apart from mammalian TNF alpha, LTA, TNFSF15 and fish TNFa proteins. Expression studies demonstrated that CsTL mRNA is present in all tested tissues from unchallenged ascidians and its expression was significantly upregulated in hemocytes following LIPS injection. The recombinant CsTL protein expressed using a baculovirus expression system showed potential cytotoxic activity in L929 cells. Present results indicated that TNF ligand superfamity molecules are present in marine invertebrates. (C) 2008 Elsevier Ltd. All rights reserved.

Factors affecting the estimation of gas hydrate and free gas saturation

Attenuations of different types of gas hydrate cementation in fluid-saturated porous solids are discussed. The factors affecting estimation of gas hydrate and free gas saturation are analyzed. It is suggested that porosity of sediment, the P wave velocity model and methods of calculating elastic modulus are key factors in the estimation of gas hydrate and free gas saturations. Attenuation of gas hydrate-bearing sediment is closely related with the cementation types of gas hydrate. Negative anomalies of quality factors indicate that gas hydrate deposits away from grain as part of fluid. Positive anomalies of the quality factors indicate that gas hydrate contacts with solid and changes the elastic modulus of matrix. Low frequency velocity and high frequency velocity models are used to estimate gas hydrate and free gas saturation in the Blake Ridge area according to the well log data of the hole 995 in ODP leg 164. The gas hydrate saturation obtained by low frequency velocity is 10% similar to 20% of the pore space and free gas saturation is 0.5% similar to 1% of the pore space. The gas hydrate saturation obtained by high frequency velocity is 5% similar to 10% of the pore space and free gas saturation is 1% similar to 2% of the pore space.

海鞘（Ciona savignyi）性腺组织细胞、血细胞和生殖干样细胞的体外培养

随着对海洋无脊椎动物免疫、发育以及细胞生物学等方面研究的需要，海洋无脊椎动物细胞培养日益受到关注。然而，由于海洋无脊椎动物的细胞代谢途径以及生长特性与陆生哺乳动物有很大差异，细胞培养难度较大,至今尚未有连续的细胞系建立。海鞘（Ciona savignyi）属于尾索动物亚门(Urochordata)，是典型的被囊类动物。作为无脊椎动物中进化地位较高等的一类动物，海鞘在免疫、胚胎发育、细胞学等各个领域对研究脊椎动物的系统发生都有着非常重要的作用。 本文分别以海鞘的性腺组织细胞和血细胞为材料，建立和优化海鞘细胞体外培养方法和条件；另外，还识别了成体海鞘性腺内的生殖样干细胞，并对其进行了体外培养和鉴定，为进一步开展海鞘细胞体外培养最终建立细胞系积累了资料。 首先比较了4种基础培养基L-15、M199、DMEM和RPMIl640 与各种培养添加物组合、不同温度和PH值对海鞘性腺组织细胞和血细胞的体外生长的影响。结果表明，20℃，pH6.8，M199基础培养基添加10%胎牛血清最适合海鞘性腺组织细胞生长。同时对海鞘性腺的分离方法即机械解离细胞法和酶学解离细胞法进行了比较，发现机械解离细胞法最适合海鞘性腺组织细胞的分离，分离得到的细胞贴壁率和成活率高。对于海鞘血细胞的培养，20℃，pH6.8条件下，L-15基础培养基并添加10%胎牛血清对血细胞的体外存活和生长效果较好。另外，还成功的利用原代培养的血细胞检测了海鞘肿瘤坏死因子配体家族成员（CsTL）基因的表达变化。 论文还研究了海鞘细胞培养中细菌污染的鉴定和控制方法。对于培养过程中的细菌污染，通过细菌分离、培养和纯培养发现两类菌株检出率较高，均为革兰氏阴性菌。经PCR 扩增16S rDNA 基因序列片断，结果显示这两类菌株分别属于弧菌属和施万氏菌属。药敏试验结果表明，亚胺培南和氯霉素等对受检施万氏菌的敏感度较高；而受检弧菌对氯霉素和环丙沙星的敏感度高。为控制培养中的微生物污染，比较了几种抗生素组合的使用效果，其中氯霉素和亚胺培南与双抗的抗生素组合有较好的抑菌效果并对培养细胞的贴壁和生长没有影响。然而，海鞘性腺组织细胞和血细胞在体外的传代培养并未取得成功，本论文对来源于成体海鞘性腺的生殖样干细胞进行了体外培养和鉴定。结果表明，成体海鞘性腺内存在生殖样干细胞，且在体外可以生长，繁殖并且可能具有分化潜能。体外培养的过程中，生长的细胞克隆明显具有类似胚胎干细胞的形态和基因表达特点。 本研究克隆了海鞘肿瘤坏死因子配体家族成员（CsTL）基因。CsTL全长995个核苷酸编码281个氨基酸。组织表达结果显示，CsTL在性腺组织的表达水平相对比较高，提示CsTL可能对海鞘性腺的发育或分化等起着一定的作用。利用昆虫杆状病毒表达系统表达纯化了CsTL蛋白。结果显示，重组CsTL对L929细胞显示了明显的细胞毒性作用，说明CsTL是具有生物学活性的重组蛋白。但是尝试用获得的重组CsTL蛋白作为培养添加物培养海鞘性腺组织细胞，但并未检测到CsTL对海鞘性腺组织细胞的生长或凋亡有任何影响。 总之，本文筛选到了适合海鞘性腺组织细胞和血细胞生长的培养基，并成功的将这两类细胞在体外进行了原代培养，并且虽然细胞传代未获成功，但为今后继续深入开展海鞘细胞培养研究奠定了基础，另外，海鞘生殖样干细胞的识别和培养也将为海洋无脊椎动物的细胞培养提供一条新途径。

栉孔扇贝和海湾扇贝免疫防御特性的比较研究

贝类养殖作为我国传统的海水养殖产业，在我国沿海地区的经济发展中起重要作用。但由于近年来养殖扇贝病害的不断发生，不仅造成了巨大的经济损失，而且直接威胁到现有养殖产业的生存和发展。目前认为，机体抗病能力的下降是发生流行性死亡的主要原因之一。因此，深入研究扇贝免疫防御特性，能更好地了解和解决贝类养殖中的病害问题。本文比较了健康状态和重金属污染以及高温胁迫下海湾扇贝和栉孔扇贝部分免疫指标的变化，并对同龄不同大小的栉孔扇贝的部分免疫指标进行了比较，以期更好的了解贝类的防御机制，为扇贝病害防治提供资料。研究结果如下: 用流式细胞仪技术对血细胞死亡率、细胞吞噬率和呼吸爆发进行了测定，发现健康状态下两种扇贝的细胞死亡率相差不大，海湾扇贝为4.83%，栉孔扇贝为4.95%；细胞吞噬率差异显著(P<0.05)，海湾扇贝为26.73%，栉孔扇贝为19.89%；呼吸爆发的基础值相差也不大，海湾扇贝为1.94，栉孔扇贝为1.56。另外用免疫化学方法对健康状态下栉孔扇贝和海湾扇贝血淋巴和肝胰腺中SOD、ACP活性和MDA含量也进行了测定与比较。发现在血淋巴和肝胰腺中，两种扇贝SOD活性均存在显著差异(P<0.05)，其中海湾扇贝分别为995.43和113.99，栉孔扇贝分别为446.64和40.6；血淋巴和肝胰腺中ACP活性差异显著(P<0.05)，海湾扇贝分别为90.19和432.36，栉孔扇贝分别为73.26和146.63；血淋巴中和肝胰腺中MDA含量差异不显著(P>0.05)，海湾扇贝分别为3.37和92.46，栉孔扇贝分别为2.17和28.96。实验结果说明，海湾扇贝对细菌等异物的吞噬和杀灭能力以及机体自身的抗氧化能力高于栉孔扇贝，这为海湾扇贝比栉孔扇贝具有更高的抗逆性提供了证据。 用相同的方法对不同浓度(0, 0.2, 0.3, 0.5 mg L-1) Pb2+溶液浸泡后的栉孔扇贝和海湾扇贝的血细胞死亡率、细胞吞噬率和呼吸爆发进行了检测，同时测定了Pb2+处理后肝胰腺中SOD、ACP活性和MDA含量的变化。结果表明，栉孔扇贝的血细胞死亡率与对照组相比有上升趋势，且随着Pb2+浓度的增加而显著增加，而海湾扇贝在相同条件Pb2+的胁迫下，血细胞的死亡率明显低于栉孔扇贝。栉孔扇贝各实验组细胞吞噬率均低于对照组，而海湾扇贝在低浓度的Pb2+浸泡后，细胞的吞噬率与对照组相比有所降低，但随着浓度的继续增加，细胞的吞噬率反而上升，甚至略高于对照组。栉孔扇贝血细胞的呼吸爆发在Pb2+胁迫后较对照组有所升高，但随着浓度的增加，呼吸爆发有下降的趋势，而海湾扇贝的呼吸爆发随着Pb2+浓度的增加而显著增加。对两种扇贝体液免疫指标的测定发现，各实验组SOD的活性均比对照组高，且海湾扇贝的SOD活性高于栉孔扇贝；随着Pb2+浓度的增加，各实验组ACP的活性一直呈上升趋势，且海湾扇贝的ACP活性也高于栉孔扇贝；Pb2+处理后MDA的含量均显著增加，其中栉孔扇贝MDA含量的增幅明显高于海湾扇贝。该结果说明，Pb2+对两种扇贝的免疫系统都有一定的影响，但相同剂量的Pb2+对两种扇贝的毒害程度不同，海湾扇贝对Pb2+的耐受性似乎高于栉孔扇贝。 对海湾扇贝和栉孔扇贝的升温刺激实验发现，当养殖水体的温度从18℃缓慢升高到30℃后，栉孔扇贝在第三天开始出现大量死亡现象，而海湾扇贝未出现死亡。因而本文只对升温前后的海湾扇贝进行了细胞死亡率、吞噬率和呼吸爆发的测定和比较。结果发现，与升温前相比，血细胞的死亡率在温度升高后略有增加，但差异不显著(P>0.05)；而细胞吞噬率在温度升高后显著下降；通过对呼吸爆发积聚的活性氧（Reactive Oxygen Species，ROS）的测定发现，升温后血细胞的ROS含量显著高于升温前(P<0.05)。该结果表明，高温会影响血细胞的功能，使机体的免疫防御能力下降，从而导致病害的发生。 另外，本文对同龄不同大小的栉孔扇贝的血细胞吞噬率以及血淋巴和肝胰腺中SOD、ACP活性和MDA含量进行了测定与比较。结果发现: 小扇贝的血细胞吞噬率略高于大扇贝，分别达到了22.82和20.96；在血淋巴及肝胰脏中，两组扇贝SOD酶的活性均差异显著(P<0.05)，小扇贝分别为613.88和102.01，大扇贝分别为356.15和50.22；血淋巴中小扇贝ACP的活性极显著的高于大扇贝(P<0.01)，分别为44.3和2.91，但肝胰腺中大扇贝和小扇贝ACP的活性相差不大，大扇贝为455.75，小扇贝为485.33；大扇贝和小扇贝血淋巴和肝胰脏中MDA含量相差不大，大扇贝分别为2.67和31.83，小扇贝分别为3.17和35.33。该结果说明，小扇贝对细菌等异物的吞噬和杀灭能力以及机体自身的抗氧化能力高于大扇贝，这为生长与抗逆性相颉抗提供了依据。

高寒牧区三种豆科牧草与燕麦混播的试验研究

在中国科学院海北高寒草甸生态系统开放实验站进行的燕麦与箭舌豌豆、红豆草、毛苕子3 种豆科牧草混播栽培的试验研究, 采用正交设计及极差分析方法对混播组合作择优评判。结果表明: 红豆草在年均温-1. 7 ℃, ≥5 ℃积温1 000 ℃, 海拔3 200 m 的高寒地区可与燕麦建立一年生混播割草地。其产量水平高于毛苕子与燕麦混播的草地而与箭舌豌豆与燕麦混播的草地相当。对豆科牧草种(A )、混作方式(B)、混播总密度(C) 和混播比例(D) 4 个因素进行择优组合可提高单位面积牧草产量。4 种试验因素对混播草地牧草产量的效应大小依次为C> A > D> B。本试验最优组合为5 号组合(A 2B2C3D1)。

混凝土泵车布料机构自动浇筑及过程仿真

机器人化是提高工程机械施工控制自动化的关键问题·通过将泵车布料机构的浇筑区域离散为浇筑点集 ,对两浇筑点内轨迹利用冗余度机器人学的最小关节范数法的轨迹规划 ,并将两相临浇筑段自动连接和自动协调 ,从而实现了混凝土泵车布料机构浇筑过程自动轨迹规划·

A novel process for converting coalmine-drained methane gas to syngas over nickel-magnesia solid solution catalysts

A novel process is developed in this paper for utilizing the coalmine-drained methane gas that is usually vented straight into the atmosphere in most coalmines worldwide. It is expected that low-cost syngas can be produced by the combined air partial oxidation and CO2 reforming of methane, because this process utilizes directly the methane, air, and carbon dioxide in the coalmine-drained gas without going through the separation step. For this purpose, a nickel-magnesia solid solution catalyst was prepared and its catalytic performance for the proposed process was investigated. It was found that calcination temperature has significant influence on the catalytic performance due to the different extent of solid solution formation in the catalysts. A uniform nickel-magnesia solid solution catalyst exhibits higher stability than the catalysts in which NiO has not completely formed solid solution with MgO. Its catalytic activity and selectivity remain stable during 120 h of reaction. The product H-2/CO ratio is mainly dependent on the feed gas composition. By changing CO2/air ratio of the feed gases, syngas with a H-2/CO ratio between 1 and 1.9 can be obtained. The influences of reaction temperature and nickel loading on the catalytic performance were also investigated. (c) 2004 Elsevier B.V All rights reserved.

Determination of urinary nucleosides by direct injection and coupled-column high-performance liquid chromatography

A coupled-column liquid chromatographic method for the direct analysis of 14 urinary nucleosides is described. Efficient on-line clean-up and concentration of 14 nucleosides from urine samples were obtained by using a boronic acid-substituted silica column (40 turn x 4.0 mm I.D.) as the first column (Col-1) and a Hypersil ODS2 column (250 mm x 4.6 mm I.D.) as the second column (Col-2). The mobile phases applied consisted of 0.25 mol/L ammonium acetate (pH 8.5) on Col-1, and of 25 mmol/L potassium dihydrogen phosphate (pH 4.5) on Col-2, respectively. Determination of urinary nucleosides was performed on Col-2 column by using a linear gradient elution comprising 25 mmol/L potassium dihydrogen phosphate (pH 4.5) and methanol-water (60:40, v/v) with UV detection at 260 nm. Urinary nucleosides analysis can be carried out by this procedure in 50 min requiring only pH adjustment and the protein precipitation by centrifugation of urine samples. Calibration plots of 14 standard nucleosides showed excellent linearity (r > 0.995) and the limits of detection were at micromolar levels. Both of intra- and inter-day precisions of the method were better than 6.6% for direct determination of 14 nucleosides. The validated method was applied to quantify 14 nucleosides in 20 normal urines to establish reference ranges. (c) 2005 Elsevier B.V. All rights reserved.