Diffusion Coefficients and Structure Properties of Triton X-100/ n-C6H13OH/H2O System

Abstract

The diffusion coefficients of Triton X-100 micelles with different shape are determined by cyclic voltammetry without any probe. The first CMC (3.2 × 10^?4 mol-L^minus;1) and the second CMC (1.3 × 10^minus;3 mol-L^minus;1) of Triton X-100 micelles arc obtained, and the mechanism of electrochemical reaction for Triton X-100 is deduced, When n-hexanol is added, the diffusion coefficient of Triton X-100 micelles with different shape increases, but the solubilization fraction of n-hexanol decreases in spherical micelles and is almost constant in rodlike ones. However, the micropolarity of micelles decreases in both spherical and rodlike micelles. Furthermore, the diffusion coefficient of Triton X-100 micelles with different shape increases with temperature and the diffusion activation energy increases with n-hexanol content.     

香港五所大学物理实验教学情况考察报告

介绍了香港五所大学物理实验教学情况,并谈了几点收获和体会。     

Pd(NHC)(cinnamyl)Cl-catalyzed Suzuki cross-coupling reaction of aryl sulfonates with arylboronic acids

Molecular Diversity - A series of N-heterocyclic carbene (NHC)–palladium catalysts have been synthesized and applied to catalyze the Suzuki coupling reaction efficiently between aryl...     

Optimizing piezoelectric inkjet printing of silica sols for biosensor production

The effects of selected process conditions for the sol-gel encapsulation of laccase enzymatic extract, obtained from Coriolus hirsutus, were investigated. Screening trials were carried out to identify the parameters having the most pertinent effects on the encapsulation efficiency (EE) and the residual laccase activity. These parameters included water/silane molar ratio (r), HCl content and protein loading, for the pre-gel silica sol as well as the required time for gel drying and for aging, for the sol-gel process. The experimental findings indicated that a sol-gel drying time of over 6?h resulted in a complete loss of laccase catalytic activity, while an increase in the gel aging time led to an enhancement of the residual enzyme activity. Except for r, the investigated parameters demonstrated no significant effect on the EE of the sol-gel encapsulated enzymatic extract. Overall, the encapsulation of laccase extract in the sol-gel matrix resulted in an enhancement of its catalytic activity, where its highest residual activity (349%) was obtained with an r-value of 4, an HCl content of 4?µmol and a protein loading of 1?mg/mL, using 6 and 24?h of drying and aging times, respectively.

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Fluorescence study of Eu chelates in solution and polymer matrix

The fluorescence spectra of Eu chelates with different neutral ligand in methyl methacryate (MMA) solution were measured and the influence of the neutral ligand was analyzed. The chelate Eu(DBM)3(TOPO)2, which shows the strongest fluorescence intensity in the solution, has been incorporated into the poly(methyl methacryate) (PMMA) matrix. According to the fluorescence emission spectrum, its radiative properties were also predicted.     

Mild and Practical Dirhodium(II)/NHPI-Mediated Allylic and Benzylic Oxidations with Air as the Oxidant

Aerobic allylic and benzylic oxidations catalyzed by dirhodium(II) complexes with N-hydroxyphthalimide (NHPI) are described. The open flask reaction occurs at mild temperature, using air as the oxidant. Mechanistic studies suggest that dirhodium(II) complexes axially coordinate with NHPI to activate the O−H bond in NHPI and decrease the bond-dissociation energy (BDE).     

Dirhodium(II)-Catalyzed C(sp2)−H Azidation of Benzaldehydes

Multiple steps are needed to achieve the C−H functional of aromatic aldehyde, since the C−H functional reaction usually occurs preferentially at the aldehydic C−H bond over the aryl C−H bond. We report an efficient azidation method mediated by dirhodium(II) catalysts to achieve the direct aryl azidation of aromatic aldehydes avoiding the simultaneous use of protected aldehydes and prefunctionalized arenes. The regioselectivity of this method is similar to those of typical aromatic electrophilic substitution reactions. The resulting azidobenzaldehyde products are versatile building blocks or precursors for the synthesis of many biologically active compounds. The mechanism studies indicate that the one-electron oxidative intermediate Rh₂^(II,III)N₃ is responsible for the azide transfer.     

RESEARCH ON PRESSURE WAVE PROPAGATION CHARACTERISTICS IN THREE-PHASE FLOW DURING MANAGED PRESSURE DRILLING

考虑虚拟质量力、相间阻力、气相溶解度及滑脱速度等因素,在双流体模型基础上,建立了控压钻井中油-气-钻井液三相流体压力波速模型. 将溢流气体视为气相,将溢流油相及钻井液相视为液相,液相弹性模量及密度等参数为油相及钻井液相中各参数的加权和,利用半隐式差分及小扰动理论等数学方法,借助计算机编程对其求解. 结果表明,当井底气侵量从0.36m³/h 增至3.6m³/h,波速减小峰值为498.59m/s,而相同的油侵增加量,波速呈缓慢减小趋势,波速减小峰值为19.21m/s;当回压从0.1MPa 增至9.0MPa,波速呈增大趋势,波速增大峰值为233.15m/s;不考虑虚拟质量力,在低频段引起的波速误差呈增大趋势,在高频段引起的波速误差峰值稳定于10.03%.     

Generation of a Hydrophobic Protrusion on Nanoparticles to Improve the Membrane-Anchoring Ability and Cellular Internalization

Controlling the nanoparticle-cell membrane interaction to achieve easy and fast membrane anchoring and cellular internalization is of great importance in a variety of biomedical applications. Here we report a simple and versatile strategy to maneuver the nanoparticle-cell membrane interaction by creating a tunable hydrophobic protrusion on Janus particles through swelling-induced symmetry breaking. When the Janus particle contacts cell membrane, the protrusion will induce membrane wrapping, leading the particles to docking to the membrane, followed by drawing the whole particles into the cell. The efficiencies of both membrane anchoring and cellular internalization can be promoted by optimizing the size of the protrusion. In vitro, the Janus particles can quickly anchor to the cell membrane in 1 h and be internalized within 24 h, regardless of the types of cells involved. In vivo, the Janus particles can effectively anchor to the brain and skin tissues to provide a high retention in these tissues after intracerebroventricular, intrahippocampal, or subcutaneous injection. This strategy involving the creation of a hydrophobic protrusion on Janus particles to tune the cell-membrane interaction holds great potential in nanoparticle-based biomedical applications.     

Method for determination of microcystin-leucine-arginine in water samples based on the quenching of the fluorescence of bioconjugates between CdSe/CdS quantum dots and microcystin-leucine-arginine antibody

We have developed a method for the determination of microcystin-leucine-arginine (MC-LR) in water samples that is based on the quenching of the fluorescence of bioconjugates between CdSe/CdS quantum dots (QDs) and the respective antibody after binding of MC-LR. The core-shell CdSe/CdS QDs were modified with 2-mercaptoacetic acid to improve water solubility while their high quantum yields were preserved. Monoclonal MC-LR antibody was then covalently bioconjugated to the QDs. It was found that the fluorescence intensity of the bioconjugates was quenched in the presence of MC-LR. A linear relationship exists between the extent of quenching and the concentration of MC-LR. Parameters affecting the quenching were investigated and optimized. The limit of detection is 6.9?×?10^?11 mol L^?1 (3σ). The method was successfully applied to the determination of MC-LR in water samples.