Spectrofluorimetric determination of artemisinin with pyronine B as the substrate for horseradish peroxidase

Enzyme-catalytic fluorescence determination of artemisinin （qinghaosu, QHS） was developed using pyronine B （PB） as substrate of horseradish peroxidase （HRP）. The interaction between HRP and QHS was an enzyme-substrate model. The catalytic characteristic of HRP in the oxidation reaction, in which the fluorescence of PB was decreased in the presence of QHS, was studied. The steady-state catalytic rate depended upon enzyme and substrate concentrations, and the Michaelis-Menten parameters Km, Vmax and Kcat were 8.4×10^-5mol·L^-1, 7.4×10^-6mol·L^-1s^-1 and 50.23s^-1. The catalytic activity of enzyme was inhibited in the presence of deactivated agents and at high temperature, respectively. Under optimum conditions, linear relationship between fluorescence intensity change （F0-F） of pyronine B and concen- tration of QHS was in the range of 1.41×10^-7-1.27×10^-6mol·L^-1. The detection limit （3σ） was determined to be 2.7×10^-8mol·L^-1. The proposed method was applied to the concentration determination of QHS in the media of plasma or urine samples.     

新显色剂偶氮氟胂-DBF的合成及与钍的显色反应

合成了新显色剂偶氮氟胂-DBF,并研究了其与钍的显色反应,在3.84 mol•L^-1的高氯酸介质中,钍与该显色剂形成紫红色配合物,最大吸收波长为630 nm,表观摩尔吸光系数为1.63×10⁵ L•mol^-1•cm^-1, 钍含量在每25 mL 0～40 μg范围内符合比尔定律,该方法简便,灵敏度高,选择性好,用于海产品中微量钍的测定,结果满意.     

Structure and magnetic properties of vacuum annealed FePt/Ag nano-multilayers

The hard disk driver (HDD) technology has been loping quickly for recent years. An aerial density of 2 has been demonstrated by Fujitsu and Seagate espectively. To further improve the recording density, the ic effect will be a serious problem tropy of a- alloy thin films in the ordered 0 phase exhibit a perpendicular magnetic anisotropy Ku of the order of 106 J/m3 at room tempera-[1,2] and is very attractive for future high density mag- In the FePt (L10) phase, Fe and Pt atomic c axis, w…     

[Zn(bim)2]·(H2O)1.67: A metal-organic open-framework with sodalite topology

Considerable efforts have been focused on the crystal engineering of the supramolecular architectures with desired properties such as zeolitic, magnetic and electric conducting materials[1—3]. But crystal engineering is still a great challenge to the chemists since lack of control over the coordination modes of metal centers and ligands during assembly of extended structures[4]. Some successful synthetic strategies based on topologic control of building blocks have been developed especially i…     

Synthesis of layered LiMnO2 by in situ oxidationintercalation and a study of the reaction mechanism and electrochemical performance

Lithium-ion batteries have become the main candi-date for rechargeable power sources in current electronicproducts because of their high open circuit voltage, highenergy density, longevity and absence of memory effect.Layered LiCoO2 has been used commerci…     

毛细管区带电泳-电化学法检测洋葱中活性成分

采用毛细管区带电泳-电化学检测法(CE-ED)同时测定了洋葱中芥子酸、槲皮素和原儿茶酸的含量，研究了电极电位、运行液浓度和分离电压等实验参数对分离检测的影响.在优化的条件下，以直径300 μm的碳圆盘电极为工作电极，电极电位为＋950 mV(vs.SCE), 在pH 9.0的40 mmol/L的硼酸运行缓冲液中，上述3组分在25 min内可完全分离.芥子酸、槲皮素和原儿茶酸的浓度分别在2.0×10^-7-1.0×10^-4g/mL、2.0×10^-7-5.0×10^-5g/mL和5.0×10 ^-7-5.0×10^-5g/mL的范围内与峰电流呈良好线性关系，检测下限分别为1.5×10^-7g/mL、1.6×10^-7g/mL和3.6×10^-7g/mL，7次测得的三种组分峰高的相对标准偏差分别为2.70%、4.65%和1.73%，三次测得的平均回收率分别为102.2%、105.5%和100.9% .     

Degradation of organic matter in the sediments of Hongfeng Reservoir

In this work, the distribution of organic carbon, DNA and lipids in the sediments of Hongfeng Reservoir were described in addition to SO4^2- profile in pore water. The contents of organic carbon in the sediments range from 23.3 to 76.8 mg·g^-1, with the peak value appearing at the depth of 8 cm bellow the sediments water interface （SWI）, and tend to decrease gradually with sedimentation depth. The concentrations of SO4^2- decreased from 40.50 mg·L^-1 to 12.00 mg·L^-1 at SWI in top 4 cm sediment, and was kept at 12.0 mg·L^-1 bellow that depth. Newly produced organic carbon can be conserved as long as 14 years in the sediments. The contents of DNA were relatively high in top 9 cm surface sediments, as revealed by agarose gel images, close to those of organic carbon and sulphate reduction index （SRI）. This study shows that bacteria played an important role in organic matter degradation; SO4^2- is the primary electron acceptor under anaerobic condition in this reservoir; DNA in the lake sediments can provide important information for the study of cycling of nutrient elements in the lake.     

Effect of total aluminum concentration on the formation and transformation of nanosized Al13 and Al30 in hydrolytic polymeric aluminum aqueous solutions

Influence of total aluminum concentration （CAIT） on the generation and transformation of nanosized AI13 and AI30 in hydrolytic polyaluminum aqueous solutions was investigated using high field 27AI NMR and time-developed AI-Ferron complex colorimetry. When prepared at the optimal basicity （B） of Al13 generation and 80℃, the All3 species in polyaluminum solution tends to further polymerize and convert to AI30 and higher polymers when CAI; 〉0.2 mol· L^-1, but Al13 does not convert to AI30 quantificationally, as the formation of Alu from Al13 and AI30 is accelerated in the same way. The conversion rate of All3 is accelerated by the increase in CAIT. When CAlT 〉0.75 mol·.L^-1, Al13 content decreases rapidly, and AI30 content increases continuously and becomes the dominant nanometer polynuclear aluminum species. AIm is one of prerequisites of Al13 conversion to AI30. When CAI; increases and B reduces, the polymerization rate between Al13 and Aim increases, and at the same time, the dissociation reaction rate of All3 and AI30 by H^＋ also increases. The latter becomes the dominant reaction in polyaluminum solution with low B value, so AI30 decreases with the increasing CAlT. The hydrolytic polyaluminum solution with Al13 content beyond 80% can only be prepared under the condition of CAlT〈0.5 mol· L^-1 and optimal B value.     

高氯酸银-苯配合物结构的重新测定和从头计算

在低温下对高氯酸银-苯配合物AgClO₄&;#8226;C₆H₆的晶体结构进行了重新测定，晶体属斜方晶系，空间群Cmcm（#63）.晶胞参数：a=8.154 0(6)×10^-10 m， b=7.918(4)×10^-10 m， c=11.717(1)×10^-10 m，V=756.4(4)×10-³⁰m³, Z = 4, 精度偏离因子R=0.023, Rw =0.050.根据该配合物晶体结构特征和从头计算的研究结果, 与前人报道的结构数据进行了对比, 指出两次测定在结构上的差异.据此, 提出了目前在中外教科书中有关苯在与银离子配位时发生严重变形的描述有待更正的必要性.     

Fluorescence study on the interaction between apoCopC and cupric

The interaction between apoCopC and cupric was investigated by fluorescence spectra, in phosphate （20 mmol/L） buffer at pH 6.0. Results suggest that the environment is measured to be hydrophobic completely around tryptophan （83）. At the same time, apoCopC fluorescence at 320 nm was significantly quenched with the addition of cupric and the 1：1 stoichiometric ratio of apoCopC to cupric was confirmed by fluorescence. In addition, the conditional binding constants were calculated to be Kcu-copc=（1.8±0.58）×10^13 mol^-1 L on the basis of the results of fluorescence titration curves. The apoCopC has the ability to bind specifically cupric ion.     

高密度样品中天然放射性核素的分析测量方法

报告了测量铝样品中天然放射性核素²³² Th和²³⁸U质量活度结论, 即232 Th质量活度为2.3 ×10 ^{- 3}～7.0 ×10 ^{- 3} Bq/ g , ²³⁸U质量活度为0.136 ×10 ^{- 3}～0.155 ×10 ^{- 3} Bq/ g。同时也讨论了在测量高密度样品时样品对其本底辐射的自吸收及环境辐射的屏蔽修正问题, 实验表明测量方法可行。     

Double Star TC-1 observation of the earthward flowing plasmoids in the near magnetotail

We analyze Double Star TC-1 magnetic field data from July to September in 2004 and find that plas-moids exist in the very near-Earth magnetotail. It is the first time that TC-1 observes the plasmoids inthe magnetotail at X > ?13 RE. According to the difference of the magnetic field structure in plasmoids,we choose two typical cases for our study: the magnetic flux rope on August 6 with the open magneticfield and the magnetic loop on September 14 with the closed magnetic field. Both of the cases are as-sociated with the high speed earthward flow and the magnetic loop is related to a strong substorm. Theions can escape from the magnetic flux rope along its open field line, but the case of the closed mag-netic loop can trap the ions. The earthward flowing plasmoids observed by TC-1 indicate that the mul-tiple X-line magnetic reconnection occurs beyond the distance of X=?10 RE from the earth.     

Keggin型铬取代杂多离子PW11O39Cr(Ⅲ)(H2O)4-的电化学性质

 用循环伏安、交流伏安和交流阻抗法详细研究了Keggin型铬取代杂多离子PW₁₁Cr(Ⅲ)O^4-₃₉(PW₁₁Cr) 的电化学性质。循环伏安扫描表明,1.0 mmol·L^-1 PW₁₁Cr的H₃PO₄-HAc-H₃BO₃ 缓冲溶液(pH2.16)在玻碳电极上有三对氧化-还原波,发生在1.30/0.631 V处的准可逆波属于Cr(Ⅲ)/Cr(Ⅴ)电对的双电子氧化-还原响应,而位于-0.553/-0.505 V和-0.782/-0.725 V处的两对可逆波则对应于W-O骨架的双电子还原-氧化响应。PW₁₁Cr三对氧化-还原波的峰电位皆与溶液的pH有关,随着溶液pH的增大,峰电位负移,峰电流降低,阴极和阳极的峰电位差增大,电极过程的可逆性降低。由第一个W O骨架还原波的峰电流与电位扫描速率平方根的关系得到PW₁₁Cr在H₃PO₄-HAc-H₃BO₃ 溶液(pH 2.16)中的扩散系数为4.4×10^-6 cm²·s^-1。交流阻抗谱表明,Cr(Ⅲ)/Cr(Ⅴ)电对的电极过程受异相电荷传递动力学控制,由相角与频率的关系得到其动力学参数k^o 为0.67 cm·s^-1;而W-O骨架的两个电极过程则受扩散控制。PW₁₁Cr的电极过程存在吸附步骤。     

Study of CH4 and CO oxidation from electrochemical method

THE TWO FACTORS USED FOR EVALUATING THE QUALITY OF CATALYST ARE I) THE AMOUNT OF ACTIVE SITE PARTICIPATING IN THE REACTION, I.E. THE AREA OF REDOX PEAKS; AND II) THE REGENERATION FREQUENCY OF ACTIVE SITE IN THE REACTION, I.E. THE MATCH OF REDOX POTENTIALS. THE CONTRIBUTION OF EACH FACTOR HAS ITS OWN STRONG POINT IN DIFFERENT REACTIONS, WHILE CYCLIC VOLTAMMETRY (CV) IS A SUITA…     

Sm(Ⅲ)-HP配合物与DNA的作用机制

 应用紫外-可见光谱法和荧光光谱法并以中性红(NR)作光谱探针研究了Sm(Ⅲ)HP配合物与DNA的作用机制。研究表明,血卟啉(HP)与Sm(Ⅲ)的配合比n_Sm(Ⅲ)∶n_HP = 1∶ 1,Sm(Ⅲ)HP配合物与DNA的结合比n_Sm(Ⅲ)HP ∶ n_DNA = 1∶ 1,Sm(Ⅲ)HP配合物与DNA的结合常数K^θ_30℃ = 1.67×10⁴  L/mol。该过程为熵所驱动,其Δ _r H_m为4.86×10⁴ J/mol,Δ_r S_m为195.61 J/(mol·K),30 ℃时Δ_r G_m为－1.06×10⁴ J/mol。Scatchard法和探针法研究表明,Sm(Ⅲ)HP与DNA之间的结合方式主要是沟区作用。     

Novel photocatalysis oxidation system UV/Fe^2＋/air to degrade 4-CP wastewater

This paper reported the degradation of 4-CP wastewater by a novel photocatalysis oxidation system-- UV/Fe^2＋/air system, in which air was used as a cheap oxidant that reacted with the excitation state of organics to form H2O2 under the UV light. The formed H2O2 reacted with the added ferrous ion to form Fenton reaction and led to the quick degradation of organic pollutants. It was found that 4-CP could be completely removed within 40 min. The degradation of 4-CP in the UV/Fe^2＋/air system was superior to the conventional UV/Fenton system （the initial concentration of H2O2 was 22 mg·L^-1）. UV/Fe^2＋/air is an effective and cheap method for treatment of the organics that can be excited by UV light.     

Permeation of vanadium（Ⅲ, Ⅳ, Ⅴ）-dipicolinate complexes across MDCK cell monolayer and comparison with Caco-2 cells

The permeation and eytotoxicity of three insulin-mimetic vanadium（Ⅲ, Ⅳ, Ⅴ）-dipicolinate complexes were studied using the MDCK cell monolayer in comparison with the Caeo-2 cells. On MDCK cell monolayer, the apparent permeation coefficients （Papp） were estimated to be （7.5±1.0）×10^-6, （1.0±0.2）×10^-6, （1.7±0.4）× 10^-6cm/s for V（Ⅴ）, V（Ⅵ）, and V（Ⅲ）-dipie complexes, respectively. The permeability of V（Ⅴ）-dipie complexes is much better than the others, which is in agreement with its better hypoglycemie effect in animal tests. On Caeo-2 cell monolayer, Papp were found to be in the range of 1-3×10^-6 ends and not to be affected by excessive amounts of dipieolinate ligand. By contrast, the permeability in the AP→BL direction across the MDCK monolayer increased greatly in the presence of free ligands, suggesting existence of active transport mechanism of vanadium complex anions on the MDCK cells. The eytotoxieity of the three complexes was found similar and the IC50 were measured in the range of 0.6-0.9 mmol/L for MDCK cells and 1.6--2 mmol/L for Caco-2 cells. The cytotoxicity of three vanadium complexes was conceivably in consistence with their permeability, suggesting that the toxicity, permeation and cellular metabolism of vanadium complexes are closely related.     

Sensitive Determination of DNA by RLS Enhancement of Metal Ions

0　IntroductionThequantitativeanalysisofnucleicacids,especiallythemi cro determinationofnucleicacids,isbecomingmoreandmoreimportantinmanybiologicalstudies.Recently ,apromisingspectraltechnique ,whichwasbasedonthemeasurementofen hancedresonancelightscattering (RLS) [1 ,2 ] ,hasgivenrisetostronginterestbyanalystsandbiochemistsfornucleicacidsandproteinassay[3 9] .Uptonow ,manykindscompoundshavebeenfoundRLSenhancementwhilebindingtoDNA ,andallthesecompoundsarecharacterizedofpositivechargewhicha…     

缺位磷钨杂多阴离子PW11O7-39电催化降解邻苯二甲酸二甲酯

 以Keggin型缺位磷钨杂多阴离子PW₁₁O^7-₃₉(PW₁₁)为电催化剂,邻苯二甲酸二甲酯(DMP)为模型污染物,详细研究了PW₁₁对DMP降解的电催化作用。实验结果表明,在pH=2.5,E=-0.6 V和60 mL·min^-1O₂流速下,0.05 mmol·L^-1DMP反应120 min的降解率达96%,总有机碳(TOC)去除约34%。DMP的电催化降解服从准一级反应动力学模型,准一级表观速率常数(k obs)与DMP的初始浓度有关, 当DMP的初始浓度为0.05, 0.2 和0.3 mmol·L^-1时,kobs分别为2.9×10^-2, 7.5×10^-3和4.9×10^-3min^-1。     

2种捕食线虫真菌大量原生质体的快速制备与再生技术

 比较了培养基、菌龄、溶壁酶、配制酶液的缓冲溶液和酶解条件等重要因素对2种捕食线虫真菌原生质体形成的影响.采用优化后的制备条件,用较低质量浓度的酶液(5mg/mL纤维素酶,5mg/mL蜗牛酶),在短时间内(5h)蠕虫节丛孢(Arthrobotrys vermicola)原生质体得率可达0.5×10⁷～1.0×10⁷mL^-1,球状单顶孢(Monacrosporium sphaeroides)原生质体得率为0.8×10⁷～1.5×10⁷mL^-1.原生质体的再生除了受到原生质体制备方法的影响,还与再生培养基的营养成分、渗透压稳定剂及其浓度有很大关系.另外还对原生质体的释放和再生进行了详细的观察和描述.