Regularity Criterion for a Nonhomogeneous Incompressible Ginzburg-Landau-Navier-Stokes System

Applications of Mathematics - We prove a regularity criterion for a nonhomogeneous incompressible Ginzburg-Landau-Navier-Stokes system with the Coulomb gauge in ?3. It is proved that if the...     

Concise quantum associative memories with nonlinear search algorithm

The model of Quantum Associative Memories (QAM) we propose here consists in simplifying and generalizing that of Rigui Zhou et al. 1 which uses the quantum matrix with the binary decision diagram put forth by David Rosenbaum 2 and the Abrams and Lloyd's nonlinear search algorithm 3 . Our model gives the possibility to retrieve one of the sought states in multi‐values retrieving scheme when a measurement is done on the first register in time complexity. It is better than Grover's algorithm and its modified form which need steps when they are used as the retrieval algorithm. n is the number of qubits of the first register and m the number of x values for which . As the nonlinearity makes the system highly susceptible to the noise, an analysis of the influence of the single qubit noise channels on the Nonlinear Search Algorithm of our model of QAM shows a fidelity of about 0.7 whatever the number of qubits existing in the first register, thus demonstrating the robustness of our model.     

强激光与一维多原子分子离子的相互作用及高次谐波的增强

研究强激光脉冲与一维多原子分子离子的相互作用,讨论双色激光场中高次谐波转化效率的提高,并应用经典三步模型说明高次谐波平台展宽的物理机制.     

Complete NMR analysis of oxytocin in phosphate buffer

Complete NMR analysis of oxytocin (OXT) in phosphate buffer was elucidated by one‐dimensional (1D)‐ and two‐dimensional (2D)‐NMR techniques, which involve the assignment of peptide amide NH protons and carbamoyl NH₂ protons. The ¹H? ¹⁵N correlation of seven amide NH protons and three carbamoyl NH₂ protons were also shown by HSQC NMR of OXT without ¹⁵N enrichment. Copyright © 2009 John Wiley & Sons, Ltd.     

Profiling analysis of oligosaccharides in antibody pharmaceuticals by capillary electrophoresis

Carbohydrate chains in glycoprotein pharmaceuticals have important roles for the expression of their biological activities. Therefore, development of an assessment method for the carbohydrate chains is an important parameter for quality control of glycoprotein pharmaceuticals such as newly developed therapeutic antibodies. In this report, we applied capillary electrophoresis with laser-induced fluorescence detection to the analysis of carbohydrate chains after releasing with glycoamidase followed by derivatization with 3-aminobenzoic acid. We found that four major oligosaccharides present in antibody pharmaceuticals were successfully separated with good resolution. The present method showed good precision in both migration times and relative peak areas, and gave comparable accuracy with that using a derivatization method with 8-aminopyrene-1,3,6-trisulfonate.     

Facile preparation of fullerenyl boronic esters

The fullerendiol C₆₀(OH)₂(OOt-Bu)₄ 1 reacts with various arylboronic acids ArB(OH)₂ to form fullerene-containing boronic esters C₆₀(O₂BAr)(OOt-Bu)₄ in up to 95% yield depending on the structure of aryl group. Bis(pinacolato)diboron (B(OCMe₂)₂)₂ also reacts with 1 to form C₆₀(O₂BB(OCMe₂)₂)(OOt-Bu)₄. The bisboronic ester C₆₀(O)(O₂BAr)₂(OOt-Bu)₂ was also obtained starting from a tetrahydroxyl fullerene derivative C₆₀(O)(OH)₄(OOt-Bu)₂. The fullerenyl boronic esters are moderately stable in air. Single crystal X-ray structure of C₆₀(O₂BPh)(OOt-Bu)₄ was obtained.     

The Effect of Metal‐Ligand Affinity on Fe3O4_Supported Co–Rh Catalysts for Dicyclopentadiene Hydroformylation

The catalytic performances of Co‐Rh/Fe₃O₄ catalysts modified with phosphine ligands (PPh₃) and its analogues on dicyclopentadiene hydroformylation were evaluated. Among these catalysts, Co‐Rh/Fe₃O₄ modified with tris(p‐trifluoromethylphenyl)phosphine was determined to be effective for monoformyltricyclodecanes production, whereas Co‐Rh/Fe₃O₄ modified with PPh₃ or tri‐p‐tolylphosphine was effective for the diformyltricyclodecanes production. To investigate the ligand effects, the complex catalyst system (Co‐Rh/Fe₃O₄ and phosphine ligand) was subjected to pretreatment with syngas and then characterized by thermogravimetry and differential thermal analysis (TG‐DTA). It was determined that the threshold decomposition temperature reflected the corresponding Rh‐phosphine interaction strength, affecting the catalytic selectivity toward different products. A weak Rh‐phosphine interaction was desirable to produce monoformyltricyclodecanes with fast reaction kinetics, whereas a strong Rh‐phosphine complex was required for the synthesis of diformyltricyclodecanes. In addition to the selectivity rule shown in the PPh₃ series, experiments with other ligands also demonstrated similar selectivity trends.     

The influence of organic sample solvents on the separation efficiency of basic compounds under strong cation exchange mode

This study investigated the influence of organic sample solvents on separation efficiency of basic compounds under strong cation exchange (SCX) mode. The mixtures of acidic aqueous solution and organic solvent such as acetonitrile, ethanol, methanol and dimethyl sulfoxide (DMSO) were tested as sample solvents. For later-eluting analytes, the increase of sample solvent elution strength was responsible for the decrease of separation efficiency. Thus, sample solvents with weak elution strength could provide high separation efficiencies. For earlier-eluting analytes, the retention of organic sample solvents was the main factor affecting separation efficiency. Weakly retained solvents could provide high separation efficiency. In addition, an optimized approach was proposed to reduce the effect of organic sample solvent, in which low ionic solvent was employed as initial mobile phase in the gradient. At last, the analysis of impurities in hydrophobic drug berberine was performed. The results showed that using acidic aqueous methanol as sample solvents could provide high separation efficiency and good resolution (R > 1.5).     

细胞色素P450酶催化的烷烃选择性羟化

碳氢键选择氧化是合成化学领域的重要课题,其中烷烃选择性羟化反应更是面临着化学选择性、区域选择性和立体选择性等多重挑战.细胞色素P450酶广泛分布于动植物和微生物体内,是公认的多功能生物氧化催化剂. P450酶对惰性C—H键的选择性氧化具有独特优势,在催化烷烃选择性羟化反应方面拥有巨大潜力.本综述简述了P450单加氧酶及其催化烷烃选择性羟化的反应机理,梳理了来自CYP153家族、CYP52家族和其他家族的天然P450酶催化各类烷烃底物的氧化反应和选择性,讨论了理性设计和定向进化策略在开发烷烃羟化P450突变酶过程中的经典案例,介绍了底物工程、诱饵分子、双功能小分子协同催化等几种化学活化P450酶的策略及其在烷烃羟化上的应用,探讨了P450酶在烷烃选择性羟化方面所面临的挑战和解决途径,并展望了其应用前景.     

Theoretical studies on the properties of uracil and its dimer upon thioketo substitution

The influences of thioketo substitution on the properties of uracil monomer and dimer and their interactions with Zn²⁺ have been systematically investigated at the B3LYP/6-311+G^*level of theory. Those properties include the structural characteristics, acidities, ionization potentials, and singlet–triplet energy gaps of SU monomers and their dimers, where SU=2-thiouracil, 4-thiouracil, and 2,4-dithiouracil, respectively. Computational results suggest that thioketo substitution leads to an increase in the acidities of the N-H groups for both uracil and its dimer, where the N₁–H group is still the most acidic site relative to that of N₃–H group. However, the opposite behaviors are true for the ionization potentials and the singlet–triplet energy gaps of uracil monomer and its dimer, suggesting that thiouracils are more susceptible to radiation damage relative to the unsubstituted uracil. For uracil and 2-thiouracil, the corresponding triplet excited-state geometries are predicted to be highly nonplanar compared with the planar geometries of the ground state as well as 4-thiouracil and 2,4-dithiouracil upon triplet excitation. As a rule, the intermolecular H-bonds involving the sulfur atom directly have been influenced more significant than those the oxygen atom directly involved for U::U and SU::SU base pairs upon ionization and excitation. Additionally, Zn²⁺ binding is expected to lead to an increase in the stability of U::U and SU::SU base pairs.