MEKC determination of IgG in human serum via a pH‐mediated acid stacking method

An on‐column preconcentration technique, pH‐mediated acid stacking, was used in this study to improve the sensitivity of MEKC‐UV analysis of IgG in human serum. Various parameters affecting pH‐mediated acid stacking were optimized systematically. To eliminate the matrix interferences of human serum and to combine the sample pretreatment procedure with the detection methodology, silica‐coated Fe₃O₄ magnetic nanoparticles modified with N‐(2‐aminoethyl)‐3‐aminopropyl‐trimethoxysilane were prepared and employed as solid phase extraction adsorbent to remove the abundant HSA from human serum. HSA was quantitatively removed by silica‐coated Fe₃O₄ magnetic nanoparticles modified with N‐(2‐aminoethyl)‐3‐aminopropyl‐trimethoxysilanes without retaining IgG at pH 9.3. Under the optimum conditions, the sensitivity of IgG was improved 40.3‐fold using a 100 s electrokinetic injection as compared with a 6 s hydrodynamic injection. The detection limit of IgG was found to be 0.1 mg/L, and the proposed method was successfully applied for the determination of IgG in human serum with satisfactory results.     

Terphenyl substituted derivatives of manganese(II): distorted geometries and resistance to elimination

Reaction of {Li(THF)Ar'MnI(2)}(2) (Ar' = C(6)H(3)-2,6-(C(6)H(2)-2,6-(i)Pr(3))(2)) with LiAr', LiC≡CR (R = (t)Bu or Ph), or (C(6)H(2)-2,4,6-(i)Pr(3))MgBr(THF)(2) afforded the diaryl MnAr'(2) (1), the alkynyl salts Ar'Mn(C≡C(t)Bu)(4){Li(THF)}(3) (2) and Ar'Mn(C≡CPh)(3)Li(3)(THF)(Et(2)O)(2)(μ(3)-I) (3), and the manganate salt {Li(THF)}Ar'Mn(μ-I)(C(6)H(2)-2,4,6-(i)Pr(3)) (4), respectively. Complex 4 reacted with one equivalent of (C(6)H(2)-2,4,6-(i)Pr(3))MgBr(THF)(2) to afford the homoleptic dimer {Mn(C(6)H(2)-2,4,6-(i)Pr(3))(μ-C(6)H(2)-2,4,6-(i)Pr(3))}(2) (5), which resulted from the displacement of the bulkier Ar' ligand in preference to the halogen. The reaction of the more crowded {Li(THF)Ar*MnI(2)}(2) (Ar* = C(6)H(3)-2,6-(C(6)H(2)-2,4,6-(i)Pr(3))(2)) with Li(t)Bu gave complex Ar*Mn(t)Bu (6). Complex 1 is a rare monomeric homoleptic two-coordinate diaryl Mn(II) complex; while 6 displays no tendency to eliminate β-hydrogens from the (t)Bu group because of the stabilization supplied by Ar*. Compounds 2 and 3 have cubane frameworks, which are constructed from a manganese, three carbons from three acetylide ligands, three lithiums, each coordinated by a donor, plus either a carbon from a further acetylide ligand (2) or an iodide (3). The Mn(II) atom in 4 has an unusual distorted T-shaped geometry while the dimeric 5 features trigonal planar manganese coordination. The chloride substituted complex Li(2)(THF)(3){Ar'MnCl(2)}(2) (7), which has a structure very similar to that of {Li(THF)Ar'MnI(2)}(2), was also prepared for use as a possible starting material. However, its generally lower solubility rendered it less useful than the iodo salt. Complexes 1-7 were characterized by X-ray crystallography and UV-vis spectroscopy. Magnetic studies of 2-4 and 6 showed that they have 3d(5) high-spin configurations.     

Mechanism study and molecular design in controlled/“living” radical polymerization

This tutorial review summarizes recent progress in the research field of controlled/“living” radical polymerization (CLRP) from Soochow University. The present paper gives a broad overview of the mechanism study and molecular design in CLRP. The mechanism study in CLRP aided by microwave, initiated by γ-radiation at low temperature, mediated by iron, in reversible addition-fragmentation chain transfer (RAFT) polymerization and the mechanism transfer between different CLRP processes are reviewed and summarized. The molecular design in CLRP, especially in RAFT polymerization for mechanism study, and in achieving tailor-made functional polymers is studied and discussed in the later part.     

Insight into herbicide resistance of W574L mutant Arabidopsis thaliana acetohydroxyacid synthase: molecular dynamics simulations and binding free energy calculations

Acetohydroxyacid synthase (AHAS) is the target enzyme of several classes of herbicides, such as sulfonylureas and imidazolinones. Now many mutant AHASs with herbicide resistance have emerged along with extensive use of herbicides, therefore it is imperative to understand the detailed interaction mechanism and resistance mechanism so as to develop new potent inhibitors for wild-type or resistant AHAS. With the aid of available crystal structures of the Arabidopsis thaliana (At) AHAS-inhibitor complex, molecular dynamics (MD) simulations were used to investigate the interaction and resistance mechanism directly and dynamically at the atomic level. Nanosecond-level MD simulations were performed on six systems consisting of wild-type or W574L mutant AtAHAS in the complex with three sulfonylurea inhibitors, separately, and binding free energy was calculated for each system using the MM-GBSA method. Comprehensive analyses from structural and energetic aspects confirmed the importance of residue W574, and also indicated that W574L mutation might alert the structural charactersistic of the substrate access channel and decrease the binding affinity of inhibitors, which cooperatively weaken the effective channel-blocked effect and finally result in weaker inhibitory effect of inhibitor and corresponding herbicide resistance of W574L mutant. To our knowledge, it is the first report about MD simulations study on the AHAS-related system, which will pave the way to study the interactions between herbicides and wild-type or mutant AHAS dynamically, and decipher the resistance mechanism at the atomic level for better designing new potent anti-resistance herbicides.     

甲氧基在Rh(111)表面吸附的密度泛函研究

采用密度泛函理论(DFT)的B3LYP方法,以原子簇Rh13(9,4)为模拟表面,在6-31G(d,p)与Lanl2dz基组水平上,对甲氧基在Rh(111)表面的四种吸附位置(fcc、hcp、top、bridge)的吸附模型进行了几何优化、能量计算、Mulliken电荷布局分析以及前线轨道的计算。结果表明,当甲氧基通过氧与金属表面相互作用时,在bridge位的吸附能最大,吸附体系最稳定,在top位转移的电子数最多;吸附于Rh(111)面的过程中C—O键被活化,C—O键的振动频率发生红移。     

基于免疫胶体金标记技术的检测研究及其在堆肥中的应用展望

金纳米颗粒作为一种性能优异的标记物应用广泛.随后发展出来的免疫胶体金标记技术作为一种灵敏度高、操作步骤简便、检测快速的免疫反应检测技术得到广泛关注.本文介绍了免疫胶体金标记技术的基本原理、制备方法并详述了近年来该技术的新发展.此外,结合免疫胶体金标记技术在免疫检测与环境检测实际工作中的应用,展望了其在堆肥环境检测中的应用潜力和发展前景.     

Reversible DNA condensation induced by a tetranuclear nickel(II) complex

DNA condensing agents play a critical role in gene therapy. A tetranuclear nickel(II) complex, [Ni^II₄(L?2H)(H₂O)₆(CH₃CH₂OH)₂] ? 6NO₃ (L=3,3',5,5'‐tetrakis{[(2‐hydroxyethyl)(pyridin‐2‐ylmethyl)amino]methyl}biphenyl‐4,4'‐diol), has been synthesized as a nonviral vector to induce DNA condensation. X‐ray crystallographic data indicate that the complex crystallizes in the monoclinic system with space group P2₁/n, a=10.291(9), b=24.15(2), c=13.896(11) Å, and β=98.175(13)°. The DNA condensation induced by the complex has been investigated by means of UV/Vis spectroscopy, fluorescence spectroscopy, circular dichroism spectroscopy, dynamic light scattering, atomic force microscopy, gel electrophoresis assay, and zeta potential analysis. The complex interacts strongly with DNA through electrostatic attraction and induces its condensation into globular nanoparticles at low concentration. The release of DNA from its compact state has been achieved using the chelator ethylenediaminetetraacetic acid (EDTA) for the first time. Other essential properties, such as DNA cleavage inactivity and biocompatibility, have also been examined in vitro. In general, the complex satisfies the requirements of a gene vector in all of these respects.     

图的伴随多项式的最小实根

本文讨论了含割点$u$的连通图G,其中$G-u$含路、圈或$D_{n}$分支时图$G$的伴随多项式的最小实根的变化情况.得到一些新的序关系,这推广了文[10-13]中有关图的伴随多项式最小根的一些结果.     

Data fusion in multivariate calibration transfer

We report the use of stacked partial least-squares regression and stacked dual-domain regression analysis with four commonly used techniques for calibration transfer to improve predictive performance from transferred multivariate calibration models. The predictive performance from three conventional calibration transfer methods, piecewise direct standardization (PDS), orthogonal signal correction (OSC) and model updating (MUP), requiring standards measured on both instruments, was significantly improved from data fusion either by stacking of wavelet scales or by stacking of spectral intervals, as demonstrated by transfer of calibrations developed on near-infrared spectra of synthetic gasoline. Stacking did not produce as significant an improvement for calibration transfer using a finite impulse response (FIR) filter, but application of SPLS regression to FIR-transferred spectra improves predictive performance of the transferred model.     

荧光偏振技术分析全血XPD基因单核苷酸多态性的研究

将荧光偏振与非对称基因扩增技术联用,建立了可用于检测全血XPD基因单核苷酸多态性的新方法。用不等量(1∶5)的XPD基因上、下游引物对含单核苷酸多态性位点的目的片段进行非对称扩增,再用两种单核苷酸多态性序列特异的荧光标记探针对扩增产物进行检测。由于扩增得到的单链片段能够与各自不同的荧光标记探针特异结合,使荧光标记分子的分子量增加,偏振值(FP)增高。通过检测增高的FP值,可确定目的片段单核苷酸多态性。采用本方法对98例全血的XPD基因第751位密码子进行了单核苷酸多态性分析,并与传统的荧光偏振检测方法进行了比较,取得满意结果。