Assessment of the hemolysis and endothelial cell cytotoxicity induced by residual linear alkylbenzene sulfonates on pharmaceutical rubber stoppers based on HPLC‐ESI‐MS

This study was designed to develop a high‐performance liquid chromatographic–electrospray ionization–mass spectrometry (HPLC‐ESI‐MS) method for quantitative determination of residual surfactant linear alkylbenzene sulfonate (LAS) compounds on pharmaceutical rubber stoppers. An HPLC‐ESI‐MS method was developed for separation and determination of five LAS homologs (C10–C14) under gradient conditions using methanol and ammonium acetate as mobile phases. Hemolysis activity of residual LAS compounds was analyzed by spectrophotometry. Expression of interleukin (IL)‐6 and tumor necrosis factor (TNF)‐α in human umbilical vein endothelial cells (HUVECs) after LAS compound treatment was examined by enzyme‐linked sorbent assay. LAS compounds were well separated and determined by the established gradient conditions. The linear range was 0.05–8 µg/mL with correlation coefficients ≥0.997. Recoveries were from 73 to 134% and the relative standard deviation was <13.7%. There was a correlation between hemolysis rate and LAS compounds concentration when it was ≥0.8 µg/cm². LAS compounds decreased the viability of HUVECs and promoted the production of IL‐6 and TNF‐α. The developed analytical method was successful for quantitative determination of residual LAS compounds on pharmaceutical rubber stoppers and it is important to monitor and control the amount of LAS compounds on rubber stoppers. Copyright © 2015 John Wiley & Sons, Ltd.     

Periodic mesoporous silica‐supported Ni(II) organometallic complex as an active and reusable nanocatalyst for water‐medium Sonogashira coupling reaction

Phenyl‐bridged periodic mesoporous organosilicas (PMOs) functionalized with diphenylphosphino (PPh₂‐) ligands were synthesized via a surfactant‐directed self‐assembly approach, and were used as a support to immobilize Ni(II) organometallic complex by coordination interaction. In comparison with Ni‐PPh₂‐SBA‐15 and Ni‐PPh₂‐PMOs(Et) catalysts, the as‐prepared Ni‐PPh₂‐PMOs(Ph) exhibited superior catalytic reactivity and selectivity in water‐medium Sonogashira reaction. A control experiment demonstrated that its high activity could be attributed to the high dispersion of Ni(II) active sites and ordered mesopore channels, which effectively diminished diffusion limitation. Meanwhile, the phenyl organic groups in the support wall enhanced surface hydrophobicity, which promoted the adsorption for organic reactant molecules. Moreover, it displayed almost the same catalytic efficiency with the corresponding homogeneous Ni(PPh₃)₂Cl₂ catalyst and could be used repetitively, which was considered as a more environmentally friendly catalytic process since it simultaneously avoided the use of noble metal active species and toxic organic solvents. Copyright © 2013 John Wiley & Sons, Ltd.     

New mathematic model for predicting chiral separation using molecular docking: Mechanism of chiral recognition of triadimenol analogues

The purpose of this paper was to study the enantioseparation mechanism of triadimenol compounds by carboxymethylated (CM)‐β‐CD mediated CE. All the enantiomers were separated under the same experimental conditions to study the chiral recognition mechanism using a 30 mM sodium dihydrogen phosphate buffer at pH 2.2 adjusted by phosphoric acid. The inclusion courses between CM‐β‐CD and enantiomers were investigated by the means of molecular docking technique. It was found that there were at least three points (one hydrophobic bond and two hydrogen bonds) involved in the interaction of each enantiomer with the chiral selectors. A new mathematic model has been built up based on the results of molecular mechanics calculations, which could analyze the relationship between the resolution of enantioseparation and the interaction energy in the docking area. Comparing the results of the separation by CE, the established mathematic model demonstrated good capability to predict chiral separation of triadimenol enantiomers using CM‐β‐CD mediated CE.     

Phase modulation conversion and conservation in optical parametric amplifier of femtosecond laser pulses

The influence of the pump pulse, group-velocity mismatch, dispersion and self-phase modulation & cross phase modulation on the phase transfer in the OPA process were analyzed. The results show that very sharp phase modulation can be maintained in mid infrared range by optical parametric amplifier. The period and depth of the periodic modulation can also be maintained due to small group-velocity mismatching in the calculated wavelength range.     

Synthesis and Antimycobacterial Evaluation on Arylsulfonyl and Arylcarbonyl Derivatives of Ofloxacin

Four ofloxacin derivatives 3, 5, 6 , and 11 were found to exhibit > 90% inhibition on the growth of M. tuberculosis at a concentration of 6.25 μg/mL. Compounds 3, 5 and 11 have also exhibited a broad spectrum of antibacterial activities while 8‐fluoro‐3‐methyl‐9‐[4‐(4‐nitrophenylsulfonyl)piperazin‐1‐yl)‐6‐oxo‐2,3‐dihydro‐6H‐1‐oxo‐3a‐azaphenalene‐5‐carboxylic acid ( 6 ), which exhibited potent activity against the growth of TB with the MIC of 2.23 μg/mL and a selectivity index (SI) of > 14.80, was inactive against the growth of G(+)‐ and G(‐)‐bacteria. Selective anti‐TB activity was achieved by the introduction of an arylsulfonyl group at C‐7 piperazin‐4‐yl of N‐demethyl ofloxacin. Compound 6 is species‐specific, exhibiting no significant activity against the growth of bacterial species other than M. tuberculosis, which implied the possibility of developing new specific anti‐TB drug candidates without inducing cross resistance with other currently used antibacterial drugs. Structural optimization of 6 is on‐going.     

Effect and optimization of the diminution of the sensitizing intensity in two-center recording

The effect of the diminution of the sensitizing intensity from initially high value on two-center recording is experimentally and theoretically investigated. A linear diminution of the sensitizing intensity is designed,and three different diminution rates are employed for the experimental investigation. The results show that the dynamic range can be improved by reducing the diminution rate of the sensitizing intensity. Compared with that of traditional two-center recording, the recording sensitivity obtained in the experiment is more improved when the maximum dynamic range is achieved. The effect of the diminution of the sensitizing intensity on grating uniformity and the effect of the initial sensitizing intensity on the recording sensitivity are theoretically investigated.