高效液相色谱法紫外与激光诱导荧光检测蛋白质的分析对比

将鼠肝肿瘤组织蛋白及其酶解产物经4-氟-7-硝基-2,1,3-苯并氧杂恶二唑(NBD-F)在50 mmol/L硼砂缓冲溶液(pH 8.5)中室温避光衍生1h后,采用高效液相色谱-激光诱导荧光检测法(HPLC-LIF)分析(λ(ex)=473nm,λ(em)=525 mn),并与高效液相色谱-紫外检测法(HPLC-UV)...     

植物甾醇乙酰化过程中高效液相色谱法的测定

应用高效液相色谱法对混合植物甾醇乙酰化过程的产物进行了测定。实验采用的色谱柱为 HypersilODS反相柱 (4 .6× 15 0 mm,5 μm) ,流动相为甲醇 ,紫外检测波长为 2 10 nm,恒溶剂洗脱的操作条件。实验结果表明 ,混合植物甾醇及其乙酸酯的响应时间小于 2 5 min,且各种甾醇及其酯的分离效果较好。采用该方法能够快速、准确地对植物甾醇酯化反应进行的程度及酯化产物含量进行测定。     

含扑酸的三烃基锡配合物的合成及结构研究(英文)

用扑酸(H2pa,2,3-diphenylpropionic acid)和三烃基锡氯化物R3SnCl(R=Ph,Bu,Me)合成了3个有机锡配合物{[(Ph3Sn)(pa)]·Et3N}n(1)、(Bu3Sn)2(pa)(2)和[(Me3Sn)2(pa)]·CH2Cl2(3)。通过元素分析、红外光谱、核磁共振谱及X-ray单晶衍射等手段对配合物进行了表征。结构表明三苯基锡扑酸酯为一维链状聚合物,扑酸作为桥联配体链接各个锡原子,中心锡采取五配位的三角双锥构型;而三甲基锡和三丁基锡扑酸酯配合物为二核锡配合物,锡采取四配位的四面体构型。     

Triphenylmethane dyes as fluorescent probes for G-quadruplex recognition

Triphenylmethane (TPM) dyes normally render rather weak fluorescence due to easy vibrational deexcitation. However, when they stack onto the two external G-quartets of a G-quadruplex (especially intramolecular G-quadruplex), such vibrations will be restricted, resulting in greatly enhanced fluorescence intensities. Thus, TPM dyes may be developed as sensitive G-quadruplex fluorescent probes. Here, fluorescence spectra and energy transfer spectra of five TPM dyes in the presence of G-quadruplexes, single- or double-stranded DNAs were compared. The results show that the fluorescence spectra of four TPM dyes can be used to discriminate intramolecular G-quadruplexes from intermolecular G-quadruplexes, single- and double-stranded DNAs. The energy transfer fluorescence spectra and energy transfer fluorescence titration can be used to distinguish G-quadruplexes (including intramolecular and intermolecular G-quadruplexes) from single- and double-stranded DNAs. Positive charges and substituent size in TPM dyes may be two important factors in influencing the binding stability of the dyes and G-quadruplexes.     

Anaphthalimide-based fluorescent probe for mercaptocontaining compounds

A polarity-sensitive fluorescent probe MNP was rationally designed and synthesized with naphthalimide as the fluorophore and maleimide as the receptor for thiols. MNP is weakly fluorescent due to the photoinduced electron-transfer(PET) from the fluorophore to the receptor, and it displays evidently solvatochromic UV–vis and fluorescence spectra: the emission shifted from 495 nm in n-hexane to545 nm in phosphate buffer solution. Michael addition reaction between thiols and the maleimide in MNP inhibited the PET process, which led to about eight-fold fluorescence enhancement. In addition,MNP showed highly sensitivity to mercapto-containing proteins and it could detect as low as 20.4 mg/m L of BSA in PBS. MNP has potential in fluorescent imaging of thiols in living cells.     

Investigation of the Adsorption and Self Assembly of Isocyanide Derivatives on Au（111） Surface

The adsorption and self-assembly of isocyanide derivatives on Au（111） surface were investigated by density functional theory （DFF） and molecular dynamics simulation. The calculation for phenyl isocyanide by DFT was based on cluster and slab models. The self-assembled monolayers of 2-isocyanoazulene and 1,3-diethoxycarbony 1- 2-isocyanoazulene on Au（111） were simulated using Au-C force field parameters developed by us. It was found that the top site was the most preferred position, and the isocyanoazulene and its derivatives could form the ordered face to edge self-assembled monolayer on gold surface indeed, and the molecules stood on the gold surface vertically.     

Tunable thermal entanglement in an effective spin-star system using coupled microcavities

We theoretically explore the possibility of realizing controllable thermal entanglement of effective spins in a four-qubit anisotropic Heisenberg XXZ coupling spin-star system constructed by coupled microcavities. We analyse the dependence of thermal entanglement in this system on temperature, inhomogeneity of the magnetic field, and anisotropy, which can be readily tuned via the external laser fields. The peculiar characteristic and the full controllability of the thermal entanglement are demonstrated to be useful for quantum information processing.     

基于石墨烯可饱和吸收体的纳秒锁模掺铥光纤激光器

报道了一种基于石墨烯可饱和吸收体的纳秒锁模掺铥光纤激光器.该激光器采用环形腔结构,利用自制的三层石墨烯薄膜作为可饱和吸收体实现锁模.同时在腔内插入一个窄带光纤光栅,约束腔内起振的纵模数,适当调节抽运功率和偏振控制器的角度,得到了重复频率为3.8 MHz、脉宽在3.8—94.3 ns之间灵活可调的2μm纳秒锁模脉冲输出,整个脉宽调节范围超过90 ns.此外,由于获得的兆赫兹纳秒锁模脉冲时间带宽积在49—1119范围内,即存在强烈的啁啾,因而可作为2μm波段啁啾脉冲放大系统中的种子源使用.     

Bi2S3量子点敏化TiO2纳米阵列结构的制备及光电性能

利用水热法制备一维TiO₂纳米棒阵列,并采用化学浴沉积法(CBD)结合自组装技术在TiO₂纳米棒上敏化Bi₂S₃量子点,形成TiO₂/Bi₂S₃复合纳米棒阵列。系统研究了复合结构的表面形貌、晶体结构、光学及光电性能。结果表明:在修饰有三氨丙基三乙氧基硅烷自组装单分子膜(APTS-SAMs)的TiO₂纳米棒表面形成一层致密的Bi₂S₃量子点敏化层,这一技术的关键是含-NH₂末端的APTS-SAMs可有效促进Bi₂S₃的异相成核作用;Bi₂S₃的沉积时间对复合结构的光吸收及光电响应性能有决定性的影响,薄膜的光电流随着沉积时间呈先增加后减小的趋势,在沉积时间为20min时,光电流密度最大。这是因为随着沉积时间的增加,TiO₂纳米棒表面Bi₂S₃量子点密度增大,光吸收增加;而当沉积时间进一步延长时,Bi₂S₃在TiO₂纳米棒表面的大量负载而形成堆积和团聚,导致表面缺陷增多,光生电子复合几率增大,从而使光电流密度减小。     

Dealloyed carbon-supported PtAg nanostructures: Enhanced electrocatalytic activity for oxygen reduction reaction

Dealloyed PtAg/C nanostructures, prepared by selective electrochemical etching of Ag in 0.5 M H₂SO₄ from a series of alloyed Pt_mAg/C samples with atomic Pt/Ag ratio m = 0.1, 0.5, 1.0 and 1.5, were employed as cathode electrocatalysts for oxygen reduction reaction (ORR) in 0.5 M KOH. Compared with their as-prepared counterpart alloy catalysts, the dealloyed catalysts showed higher half-wave potentials (E_1/2) and significantly higher Pt mass-specific activity (MSA) data. The intrinsic activity (IA) of Pt increased more or less after the dealloying treatment but was strongly dependent on the composition (m) of the alloyed sample. The Pt IA numbers were comparable for the dealloyed catalysts derived from Pt_mAg/C of m = 0.5, 1.0 and 1.5, which were nearly twice that for E-TEK Pt/C catalyst and 3 times that for the dealloyed catalyst derived from Pt_0.1Ag/C.