Electrochemical Studies of Pirarubicin and Its Interaction with DNA at a Co／GC Ion Implantation Modified Electrode

IntroductionIon implantation is a new material surfacemodification technique.It has been also applied tostudying the electrochemical behaviors of organicdrugs and biological materials as well as their de-terminations. This method offers good stability,reproductivity and catalytic activity[1] .Pirarubicin( THP) is an active highly effective and new antitu-moral anthracycline antibiotic,which has gainedwidespread clinical use in the chemotherapeutictreatment of a variety of human cancers.The d…     

Tunable capsule space: self-assembly of hemispherical cavitands with hydrogen-bonding linkers

Fine and/or drastic tuning of capsule space has been attained by alteration of the hydrogen-bonding linker and/or hemispherical cavitand, respectively. Two molecules of tetracarboxyl-cavitand 1 or tetrakis(4-carboxyphenyl)-cavitand 2 as a hemisphere and four molecules of 2-aminopyrimidine (2-AP) or tetrahydro-2-pyrimidinone (THP) as an equatorial hydrogen-bonding linker self-assemble into a capsule [(1)2.(2-AP)4] (3), [(1)2.(THP)4] (4), [(2)2.(2-AP)4] (5), or [(2)2.(THP)4] (6), respectively, via 16 hydrogen bonds. These capsules provide isolated nanospace and can encapsulate one guest molecule (7-13) in solution. Each capsule has a different cavity size and shows particular guest selectivity on the competitive encapsulation experiments.     

EXAFS/FT-IR characterization of tetra-iridium carbonyl clusters bound to tris-(hydroxymethyl)phosphine grafted silica surface catalytically active for propene oxidation to acetone

Structure and catalytic activity of Ir₄(CO)₁₂ bound to tris-(hydroxymethyl)phosphine (THP) grafted silica (THP/SiO₂) was investigated by means of EXAFS, FT-IR and kinetic studies. It was found that Ir₄(CO)₁₂ was uniformly attached on THP/SiO₂ by substitution of CO by THP (Ir₄/THP/SiO₂). The tetra-iridium carbonyl cluster framework was remained during the substitution of THP ligands and two THP ligands coordinated to the iridium carbonyl clusters to form Ir₄(CO)₁₀(THP/SiO₂)₂. species. When Ir₄/THP/SiO₂ was evacuated at 373 K, bridge CO was desorbed and Debye-Waller factor of Ir---Ir contribution derived from EXAFS analysis was increased which suggested that the cluster framework was distorted by the evacuation at 373 K. The resulting sample evacuated at 373 K was an active catalyst for hydroformylation of ethene and partial oxidation of propene, while the Ir₄/THP/SiO₂ without evacuation exhibited poor catalytic activities. The propene oxidation reaction proceed on the Ir₄/THP/SiO₂ evacuated at 323–353 K under subatmospheric pressures to give acetone as a product in high selectivity. The ethene hydroformylation proceed on the evacuated Ir₄/THP/SiO₂ at lower temperatures compared with other conventional iridium catalysts. EXAFS characterization and kinetic studies suggested that the catalytic activities were associated with the structural distortion of the iridium cluster framework due to surface attachment by the bidentate phosphine substitution.     

Polarographic Studies on Associations of Midecamycin and Chloroquine with Hydrogen Peroxide

IntroductionReactive oxygen species( ROS) including su-peroxide anion O· -2 ,hydrogen peroxide H2 O2 andhydroxyl radical OH· form in human body as a re-sult of various biochemical processes.ROS may beessential for many cellular functions such as bacte-rial ingestion and the redox regulation of signaltransduction.However,it is also recognized thatROS as harmful agents cause severe damage to sev-eral cell components ( nucleic acids,proteins,polyoses,lipoids,DNA,etc.) ,resulting in thepat…     

On the structural diversity of Shiga toxin glycosphingolipid receptors in lymphoid and myeloid cells determined by nanoelectrospray ionization tandem mass spectrometry

Shiga toxin (Stx, synonymous to verotoxin, VT) binds with high and low affinity to the globo‐series neutral glycosphingolipids (GSLs), globotriaosylceramide (Gb3Cer or Galα4Galβ4Glcβ1Cer, also known as CD77) and globotetraosylceramide (Gb4Cer or GalNAcβ3Galα4Galβ4Glcβ1Cer), respectively, which represent the targets of Stxs on many different cell types. B‐cell‐derived Raji cells and THP‐1 cells of monocytic origin are widely used for the investigation of Stx‐mediated cellular response, because Stx is known to cause cell death in both cell lines. Despite their functional importance, the Stx receptors of Raji and THP‐1 cells have so far not been investigated. This prompted us to explore the structures of their GSL receptors in detail by means of nanoelectrospray ionization quadrupole time‐of‐flight mass spectrometry (nanoESI‐QTOF‐MS) with collision‐induced dissociation (CID) in conjunction with Stx1 as well as anti‐Gb3Cer and anti‐Gb4Cer antibodies. Using the combination of a thin‐layer chromatography (TLC) overlay assay and MS¹ and MS² analysis we identified Gb3Cer (d18:1, C24:1/C24:0) as the prevalent Stx1‐receptor accompanied by less abundant Gb3Cer (d18:1, C16:0) in the neutral GSL fraction of Raji cells. The same Gb3Cer species but with almost equal proportions of the C24:1/C24:0 and C16:0 variants were found in THP‐1 cells. In addition, unusual hydroxylated Gb3Cer (d18:1, C24:1/C24:0) and Gb3Cer (d18:1, C26:1) could be identified in trace quantities in both cell lines. As the most obvious difference between Raji and THP‐1 cells we observed the expression of Gb4Cer in THP‐1 cells, whereas Raji cells failed to express this elongation product of Gb3Cer. Both short‐ and long‐chain fatty acid carrying Gb4Cer (d18:1, C16:0) and Gb4Cer (d18:1, C24:1/C24:0), respectively, were the prevalent Gb4Cer variants. This first report on the differential expression of Gb3Cer and Gb4Cer and their structural diversity in lymphoid and myeloid cell lines supports the hypothesis that such heterogeneities might play a functional role in the molecular assembly of GSLs in membrane organization and cellular signaling of Stx‐susceptible cells. Copyright © 2010 John Wiley & Sons, Ltd.     

Zur Präparation silicatischer Proben für die Röntgenfluorescenzanalyse

4 sample preparation-techniques and tests of precision for routine analysis of silicate powders are described: a) handpacked, ground material, b) pressed powders, c) lithium tetraborate fusion-briquets, d) glass disks of this fusion. Best precision is obtained using procedure b), but there are difficulties in the determination of some elements (e.g., Mg, P). Therefore, preparation c) using a dilution 1∶1 to ca. 1∶10 is preferred. The relative standard deviation for the major elements Al to Fe is less than 1%.     

Effect of Dilution Ratio on Amount of Asphaltenes Separated from Stock Tank Oil

We have investigated the effect of n‐alkane dilution on the amount of asphaltene separated from stock ‐tank oil. Asphaltenes were produced from three different oils by mixing each oil with varying amounts of n‐alkanes, including n‐pentane, n‐hexane, and n‐heptane. The n‐alkane:oil ratio ranged from 1∶1 to 1000∶1. With increasing n‐alkane:oil ratio, the amount of separated asphaltene initially increased, passed through a maximum, then decreased gradually with further dilution. The maximum occurred at an n‐alkane:oil ratio of around 30∶1 to 40∶1 for n‐hexane and n‐heptane, and 80∶1 for n‐pentane. A two‐component thermodynamic model based on Flory‐Huggins theory was adapted to match the observed trend of produced asphaltene by assuming a polydisperse model of the asphaltene fraction.     

Microwave-assisted preparation of dialkylimidazolium tetrachloroaluminates and their use as catalysts in the solvent-free tetrahydropyranylation of alcohols and phenols

Microwave-assisted preparation of dialkylimidazolium tetrachloroaluminates, [CnMIM][AlCl4] and their application as recyclable catalysts for the efficient and eco-friendly protection of alcohols as tetrahydropyranyl (THP) ethers are described. The same catalyst can also be utilized for the deprotection of THP ethers.     

超高效液相色谱-四极杆/静电场轨道阱高分辨质谱快速精准测定粮食中多种真菌毒素

采用直接提取稀释的快速前处理方法,结合稳定同位素稀释技术,利用超高效液相色谱-四极杆/静电场轨道阱高分辨质谱,建立了粮食中16种真菌毒素的快速精准分析方法。样品采用乙腈-水-乙酸溶液(70∶29∶1,体积比)提取,以C18色谱柱进行色谱分离,通过全扫描模式进行定量检测,并采用稳定同位素稀释以减少基质效应对定量分析的影响。结果表明,16种真菌毒素在一定浓度范围内均具有良好的线性关系,相关系数(r2)均大于0.999,4种常见粮食基质(小麦、玉米、大米、大麦)的限量浓度水平的加标回收率(n=6)为75.3%~123.5%,相对标准偏差为0.41%~14.7%。该方法简单、准确,适用于粮食中真菌毒素的检测,可满足日常监测工作的需要。     

Synthesis and X-ray structures of water-soluble tris(hydroxymethyl)phosphine complexes of rhodium(I)

The water-soluble Rh(I)-THP complexes: RhCl(1,5-cod)(THP) (), [Rh(1,5-cod)(THP)(2)]Cl (), RhCl(THP)(4) (), and trans-RhCl(CO)(THP)(2) () have been synthesized and characterized, where THP = P(CH(2)OH)(3); - are the first potentially useful entries into Rh(I)-THP chemistry, while and are the first structurally characterized Rh(I)-THP complexes.     

4-羟丁基缩水甘油醚的合成

以1,4-丁二醇（BDO）和环氧氯丙烷(ECH）为原料,经一步法合成了丙烯酸羟丁基缩水甘油醚中间体4-羟丁基缩水甘油醚（4-HBGE）,其结构经¹H NMR和MS(ESI)确证。对反应条件进行了优化,最佳反应条件为：BDO 0.1 mol,四丁基溴化铵(5 wt%)为催化剂,n(ECH: n(BDO)为1 : 2, n(NaOH) : n(BDO)=1:1.5,甲苯/水（V/V=1/1）为溶剂,于40 ℃反应6 h,经二级萃取法提纯,4-HBGE收率和纯度分别为69.5%和97.6%。     

甲苯作为环糊精包合作用的空间调节器的研究

以芘为模拟荧光探针 ,研究了甲苯对γ -环糊精 (γ -CD) -芘 (Py)包合体系的影响。发现Py -γ -CD -甲苯形成 1∶1∶1的包合物 ,并测出该包合物的包合常数。结果表明 :甲苯的加入 ,大大增强了γ -CD内腔与Py的结合力。     

掺硼p型非晶硅薄膜的制备及光学性能的表征

以高氢稀释的硅烷(SiH₄ )为反应气体,硼烷(B₂H₆)为掺杂气体,利用RF-PECVD方法,在玻璃衬底上制备出掺硼的氢化非晶硅(a-Si:H)薄膜,研究了硼掺杂量对氢化非晶硅(a-Si:H)薄膜的光学性能的影响.利用NKD-7000 W光学薄膜分析系统测试薄膜的透射谱和反射谱,并利用该系统的软件拟合得出薄膜的折射率、消光系数、吸收系数等光学性能参数,利用Tauc法计算掺硼的非晶硅薄膜的光学带隙.实验结果表明,随着硼掺杂量的增加,掺杂非晶硅薄膜样品在同一波长处的折射率先增大后减小,而且每一样品均随着入射光波长的增加而减小,在波长500 nm处的折射率均达到4.3以上;薄膜的消光系数和吸收系数随着硼掺杂量的增大而增大,在500 nm处的吸收系数可高达1.5×10⁵cm^-1.在实验的硼掺杂范围内,光学带隙从1.81 eV变化到1.71 eV.     

6-硝基喹哪啶的合成工艺改进

以I2/KI为氧化剂,甲苯为乳化剂,对硝基苯胺(2)和巴豆醛(3)经环合反应合成了6-硝基喹哪啶(1)。最佳反应条件为:28.92 mmol,甲苯10 mL,混酸45.5 mL[V(AcOH)∶V(HCl)=1∶90],n(2)∶n(I2/KI)=1∶1,于100℃反应4 h,收率达93.1%。1的结构经1HNMR,IR和元素分析表征。     

Microwave-assisted preparation of imidazolium-based tetrachloroindate(III) and their application in the tetrahydropyranylation of alcohols

Microwave-assisted preparation of 1-alkyl-3-methylimidazolium tetrachloroindate(III), [Rmim][InCl₄] (R = methyl, ethyl, butyl, hexyl, octyl) and their application as recyclable catalysts for the efficient and eco-friendly protection of alcohols to form tetrahydropyranyl (THP) ethers are described.     

超声波辐射下异阿魏酸对氯苯酚酯的一步合成

室温超声辐射下,4-二甲氨基吡啶(DMAP)作催化剂,二环己基碳二亚胺(DCC)作脱水剂,不需保护异阿魏酸分子中的羟基,异阿魏酸和对氯苯酚的一步反应直接合成了异阿魏酸对氯苯酚酯。在n(异阿魏酸):n(对氯苯酚):n(DCC):n(DMAP)=1:1.2:1.2:0.1混合时,室温超声反应2.5h,得产率76.2%。目标化合物的结构经元素分析、1HNMR和IR测试技术得到确证。缩短了反应时间,提高了产率。     

Novel bacteriochlorine for high tissue-penetration: photodynamic properties in human biliary tract cancer cells in vitro and in a mouse tumour model

Photodynamic therapy of bile duct cancer using hematoporphyrin derivative (HPD) and laser light of 630 nm wavelength is confined to a tumouricidal tissue penetration of 4 mm, which might be doubled with laser light between 700 and 800 nm. Therefore, we investigated the photosensitising properties of a novel bacteriochlorine, tetrakis-pyridyl-tetrahydroporphyrin tosylat (THP) with high absorption at 763 nm. Two biliary cancer cell lines (BDC, GBC) were incubated with HPD or THP to assess cellular uptake kinetics, dark cytotoxicity, and photodynamic cytotoxicity (laser light exposure 1-20 J/cm2). Tumours grown from BDC cells in subcutaneous tissue of severe combined immunodeficient mice were treated with laser light of 30 J/cm2 after injection of THP. The concentrations that killed 50% of cells in the dark were 680 microg/ml of HPD, but > 6400 microg/ml of THP in BDC cells, and 220 microg/ml of HPD, but 6400 microg/ml of THP in GBC cells. Both cell lines exhibited uptake and retention of THP and photodynamic cytotoxicity (up to 86% cells killed). THP induced tumour-selective phototoxicity in the cholangiocarcinoma model. The novel bacteriochlorine THP exhibits photosensitiser properties in biliary tract cancer cells in vitro and in vivo and could achieve deep tumouricidal tissue penetration due to photoactivation at 763 nm.     

Tamm-Horsfall glycoprotein enhances PMN phagocytosis by binding to cell surface-expressed lactoferrin and cathepsin G that activates MAP kinase pathway

The molecular basis of polymorphonuclear neutrophil (PMN) phagocytosis-enhancing activity (PEA) by human purified urinary Tamm-Horsfall glyco- protein (THP) has not been elucidated. In this study, we found human THP bound to lactoferrin (LF) and cathepsin G (CG) expressed on the surface of PMN, identified by a proteomic study with MALDI-TOF- LC/LC/mass spectrometric analysis. Pre-incubation of 10% SDS-PAGE electrophoresed PMN lysates with monoclonal anti-LF or anti-CG antibody reduced the binding with THP. To elucidate the signaling pathway of THP on PMN activation, we found THP enhanced ERK1/2 phosphorylation, reduced p38 MAP kinase phosphorylation, but had no effect on DNA binding of the five NF-kB family members in PMN. To further clarify whether the carbohydrate-side chains or protein-core structure in THP molecule is responsible for THP-PEA, THP was cleaved by different degrading enzymes with carbohydrate specificity (neuraminidase and β-galactosidase), protein specificity (V8 protease and proteinase K) or glycoconjugate specificity (carboxylpeptidase Y and O-sialoglycoprotein endopeptidase). We clearly demonstrated that the intact protein-core structure in THP molecule was more important for THP-PEA than carbohydrate-side chains. Putting these results together, we conclude that THP adheres to surface-expressed LF and CG on PMN and transduces signaling via the MAP kinase pathway to enhance PMN phagocytosis.     

钾长石矿热分解过程的研究

研究了钾长石矿热分解过程的反应行为和动力学.对6种钾长石体系进行了热力学分析,计算了各反应在800～1600K的△G_T⁰,并以此指导实验.研究了焙烧温度、停留时间和助剂配比对钾长石体系热分解为水溶性钾的影响,得出最佳操作条件.添加0.9%添加剂Ⅰ能使适宜焙烧温度由1323K降至1223K,钾分解率可达84%.不加与加入添加剂Ⅰ的2种钾长石体系热分解过程皆符合克-金-布动力学方程,均受固膜扩散控制,表观活化能分别为184.84kJ/mol和158.9kJ/mol,并给出相应的动力学方程.     

超高效液相色谱-串联质谱法检测鸡粪中16种残留抗生素

建立了固相萃取-超高效液相色谱-串联质谱(UPLC-MS/MS)同时检测畜禽粪便中四环素类、磺胺类、氟喹诺酮类和大环内酯类16种抗生素的分析方法.针对目标物化学性质和样品杂质情况,对质谱条件、提取液种类、超声功率等参数进行了优化.最终以50%乙腈(V/V)的磷酸盐缓冲溶液(pH=4)提取3次,经过超声、离心、旋蒸、稀释后,SAX-HLB串联小柱净化富集,用10 mL甲醇-丙酮混合液(80∶20,V/V)洗脱,35℃氮吹近干后,用含0.1%甲酸-甲醇(1∶1, V/V)定容,在UPLC-MS/MS多反应检测模式下进行定性及定量分析.结果表明,粪便中四环素类、磺胺类、氟喹诺酮类和大环内酯类抗生素的平均加标回收率为56.4%~94.6%,相对标准偏差(RSD)在2.6%~19.8%之间,方法检出限(LOD, S/N=3)和定量限(LOQ, S/N=10)分别为0.01~2.50 μg/ kg和0.05~7.90 μg/kg.本方法简便、稳定性好、灵敏度高、重现性好,适用于畜禽粪便中多种抗生素的同时检测.