手性双修饰剂修饰的CdSe纳米晶的合成及选择性识别Hg(II)的研究

以手性化合物D-青霉胺和L-半胱氨酸为双修饰剂在水相中合成了CdSe纳米晶, 痕量Hg(II)对其荧光强度有明显猝灭作用,基于此建立了定量测定痕量Hg(II)的新方法.在Cd2+, HSe-, D-Pen和L-Cys摩尔比为1: 0.25: 2: 1.2, pH=7.5的条件下,合成的纳米晶具有更好的发光强度和稳定性.TEM显示CdSe纳米晶为球形颗粒,粒径约为50和80 nm.在磷酸盐缓冲溶液(pH 7.38)中,CdSe纳米晶最大荧光峰为516 nm,对Hg(II)有高选择性响应.纳米晶的相对荧光强度与Hg(II)的浓度呈良好线性关系, 检出限为40 pmol/L.本方法测定不同水样中Hg(II)的浓度,回收率为96.7%～102.5%.     

荧光法和分子对接研究4种黄酮与血清白蛋白的相互作用

结合分子对接理论和荧光法研究4种黄酮类天然产物与白蛋白的相互作用及作用机理。用FlexX软件研究了黄芩素、黄芩苷、汉黄芩素、灯盏乙素和白蛋白的分子对接,然后用荧光法研究这4种黄酮类天然产物与牛血清白蛋白的结合反应,测定了结合常数KA、结合位点n等参数。研究表明:4种天然产物与牛血清白蛋白结合位点n≈1,温度对结合位点影响不大;黄芩素和汉黄芩素主要通过疏水作用力与白蛋白结合,而黄芩苷和灯盏乙素主要通过氢键和范德华力与白蛋白结合。荧光实验和分子对接理论研究结果一致,两者相互补充,能够从实验和理论两方面协同研究天然产物与蛋白之间的相互作用。     

Kinetic surface roughening of electrodeposited amorphous PdP and NiP films – A comparative study

Kinetic surface roughening of electrodeposited PdP and NiP amorphous films were investigated by atomic force microscopy and X-rays phase-contrast radiography. Anomalous scaling of the interface width was observed for PdP system, with H = 0.75 ± 0.06, β_loc = 0.49 ± 0.07 and β = 0.38 ± 0.08. In contrast, NiP system shows normal scaling behavior, with H = 0.70 ± 0.02 and β = 0.16 ± 0.03. The results suggest that surface roughening during film growth is strongly influenced by local behaviors like hydrogen evolution reaction, which shifts surface roughening from normal scaling in NiP to anomalous scaling in PdP.     

Level Statistics for the Nilsson Single-Particle Levels

We perform level statistics of the Nilsson single-particle levels. The effects of the l2 and l ＆#12539; s; s terms are discussed as well as their interplay with the deformations. The results show that when the l2 term is added to the harmonic oscillator potential, chaotic motion occurs. The strength ranges of the l2 term in which chaotic motion exists are related to the deformation of the harmonic oscillator potential. The calculations of the localization length in different bases demonstrate that it is the spherical or axial symmetries that govern the chaotic motion. The degree of chaoticity increases significantly with the l ＆#12539; s; s term included.     

锯齿尾缘降噪翼型优化设计研究

大量研究工作表明旋转风电叶片的主要气动噪声来自叶尖尾缘区域,一直以来都是严重影响居民生活和叶片气动性能发挥的重要因素之一.为此,针对决定叶片重要气动特性单元——二维翼型,采用有别于传统的仿猫头鹰翅膀锯齿尾缘流动控制方法,将锯齿关键尺寸参数融入到风力机翼型设计之中,从而开发仿生锯齿翼型的优化设计方法,获得低噪声与高气动性...     

以AmberlystA－27为载体的光纤铁反射传感器的研究

以ＡｍｂｅｒｌｙｓｔＡ－２７为载体的光纤铁反射传感器的研究卢建忠，章竹君（南京大学化学系，南京，２１０００８）（陕西师范大学化学系，西安，７１００６２）关键词光纤传感器，反射，铁离子金属离子光纤传感器的设计是基于固定在探头上的指示剂与溶液中金属离子之...     

N,N′-双(2-吡啶乙基)二硫代草酰胺根桥联的异三核锰(Ⅱ)铜(Ⅱ)锰(Ⅱ)、镍(Ⅱ)铜(Ⅱ)镍(Ⅱ)和三核镍(Ⅱ)配合物的合成及性质

以取代的二硫代草酰胺根作为桥联配体, 合成了3种新的三核镍配合物[Ni₃(Ped)₂](ClO₄)₂(H₂O) (1)、[Ni₃(Ped)₂](NO₃)₂(H₂O) (2)和[Ni₃(Ped)₂](Ac)₂(H₂O)₂ (3),及2种新的异三核铜镍和铜锰配合物[CuNi₂(Ped)₂](NO₃)₂(H₂O)₂ (4)和[CuMn₂(Ped)₂](NO₃)₂(H₂O)₂ (5) (H₂Ped =N,N′-双(2-吡啶乙基)二硫代草酰胺)。通过元素分析、红外光谱、紫外可见光谱、电导、电子顺磁共振谱等对配合物进行了表征，对配合物进行了热分析。测定了配合物(5)的变温磁化率，研究了配合物(5)中Cu(Ⅱ)-Mn(Ⅱ)离子间的磁相互作用，结果表明在Cu(Ⅱ)-Mn(Ⅱ)离子间的磁相互作用具有高自旋基态的非正规自旋态性质。     

Validation Method for the Determination of Sulfonamide Residues in Bovine Milk by HPLC

A simple, rapid, sensitive and reliable high-performance liquid chromatographic method for the simultaneous determination of eight sulfonamides (SAs) in bovine milk was developed (sulfadiazine, sulfathiazole, sulfamethazine, sulfamethoxypyridazine, sufamonomethoxine, sulfamethoxazole, sulfadimethoxine and sulfaquinoxaline) in bovine milk was developed. Samples were prepared by extraction with ethyl acetate and cleaning-up with an anion solid-phase extraction (SPE) column. Analytical separation was performed on an Inertsil ODS-3 column with photodiode-array detection at 270 nm under gradient condition. The whole procedure was evaluated according to the European Commission Decision 2002/657/EC. Specificity, decision limit (CCα), detection capacity (CCβ), trueness and precision were determined during the validation process. It was found that the analytes were isolated from spiked samples with good recoveries between 70.5 and 89.0%. The used analytical conditions allow to successively separating all the tested sulfonamides with good limit of detection between 0.8 and 1.5 μg L⁻¹.     

Purification and partial characterization of an extracellular ribonuclease from a mutant of Aspergillus niger

A new extracellular ribonuclease (RNase) from a mutant of Aspergillus niger, named A. niger SA-13-20 RNase, was purified to homogeneity by (NH4)2SO4 fractionation (50-85%), DEAE-cellulose anion-exchange chromatography, ultrafiltration and Sephacryl HR-200 chromatography. The enzyme was purified up to 54.4-fold with a final yield of 24.5%. There were differences in the molecular weight, pI value and some physico-chemical properties between A. niger SA-13-20 RNase and that from the parent strain. The enzyme is monomeric and its molecular weight and isoelectric point were 40.1 kDa and 5.3, respectively. The N-terminal amino acid sequence of A. niger SA-13-20 RNase was TIDTYSSDSP. The optimum pH, temperature and buffer concentration for the enzymatic reaction were 3.5, 65 degrees C, and 0.175 M, respectively. Metal ions, such as K+, NH4+, Mg2+, and Ca2+ at the concentration of 1.0 mM had a slight activation effect on the enzyme activity and (NH4)2SO4 activated the enzyme significantly. The enzyme was stable at pH lower than 8.5 and was easy to inactivate in strong alkali solution.     

Crystal Structure Investigation of 2-Pheny limidazo [f]1,10-phenanthroline

The crystal structure of the title compound (PIP) has been determined by single crystal X-ray diffraction methods. C₁₉H₁₂N₄. C₂H₅OH crystallizes in the monoclinic space group P2₁/n with a = 11.4414(8), b = 12.6052(9), c = 12.4627(8) Å, β = 100.345(2)°, Z = 4, V = 1768.17 ų, D_cal = 1.286 Mg. m⁻³, μ (MoKα) = 0.80 cm^-1, F(000) = 720. The structure was solved by the direct methods and refined by full-matrix least-squares method to a final R = 0.0337 and R_w = 0.0332 for 2306 reflections with F₀ > 4σ(F₀). The phenl ring and the imidazo[f]1,10-phenanthroline moiety are coplanar in the crystal. The packing of the molecules involves hydrogen bonded association of the hydroxyl group of ethanol both with the N H of the imidazole moiety of one PIP and one nitrogen atom of the phenanthroline moiety of another PIP.