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Five β-cyclodextrin (β-CD) derivatives bearing substituted phenylcarbamate/3-(triethoxysilyl)propylcarbamate groups at the 2-, 3-, and 6-positions of glucose unit and another five derivatives containing benzoate at the 2-position and substituted phenylcarbamate/3-(triethoxysilyl)propylcarbamate groups at the 3- and 6-positions were synthesized using the regioselective esterification method. The obtained β-CD derivatives were efficiently immobilized onto the silica gel through the intermolecular polycondensation of a small amount of the triethoxysilyl groups, which were used as the chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC). The chiral separation properties of these CSPs were evaluated under the normal-phase HPLC. The effects of solvent polarity and the side chain structures of β-CD derivatives on the chiral recognition ability of the immobilized CSPs were investigated. Among these β-CD derivative CSPs, 2,3,6-tris(3,5-dichlorophenylcarbamate)-β-CD CSP showed a...

A novel cross-linked chitosan-poly(aspartic acid) chelating resin was synthesized by combining chitosan and poly(aspartic acid) derivative with crosslinker. The structure and morphology of the resin containing disulfide bonds were characterized by 1H NMR, FT-IR, Raman spectra, and SEM. Adsorption of Pb(II) and Hg(II) from aqueous solution by the resulted chelating resin was investigated in batch techniques. The result of the Raman spectra suggests that the disulfide bonds in the resin also play an important role in the adsorption of Pb(II) and Hg(II). The kinetic data were fitted to pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, which is suggestive of following closely the pseudo-second-order kinetic model. Equilibrium data were fitted to Langmuir, Freundlich, and D–R isotherm models. The results of equilibrium isotherm reveal that the empirical Langmuir equation provides an accurate description of the experimental data under the studied concentration range. In addition, thermodynamic and regeneration properties of the adsorbent were also studied.

Comparative studies of enantioseparation of some amino acids and N-protected amino acids were performed using a Chiralpak IA column in normal phases HPLC. Better resolution results were obtained for N-protected amino acids compared with the studied amino acids at the same conditions. The effects of type and concentration of alcohol modifier in mobile phase, concentration of acidic additive trifluoroacetic acid, and column temperature on enantioseparation were also investigated. The experimental results showed that the separation factor and resolution factor were both high when ethanol was used as alcohol modifier in mobile phase. When the mobile phase contained 35% (v/v) ethanol, the separation factor of all the enantiomers was the highest. A trace amount of trifluoroacetic acid promotes enantioseparation regardless of the nature of the chiral solutes. The retention time of investigated enantiomers decreased with the increase of column temperature. The chromatographic peak shape of enantiomers separation ...

PurposeThe purpose of this investigation was to synthesize a doped polyaniline‐containing coating and investigate the anti‐corrosion properties of the coating on Mg‐Li alloy.Design/methodology/approachThe doped polyaniline pigments were prepared by two different methods using ammonium persulphate as oxidant and hydrochloric acid, phosphoric acid, p‐toluene sulfonic acid and sulfosalicylic acid as doping agents. The doped polyaniline was characterized by Fourier transform infrared (FT‐IR) analysis, X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The coatings consisted of polyaniline, epoxy resin and other additives that were formed on Mg‐Li alloy. The anti‐corrosion properties of the polyaniline‐containing coating on the Mg‐Li alloy were investigated in 3.5 wt.% NaCl solution using open circuit potential logging and electrochemical impedance spectroscopy.FindingsThe results of the electrochemical tests indicated that the polyaniline‐containing coatings showed better anti‐corrosion properties, as compared to conventional epoxy coatings on Mg‐Li alloy when exposed in 3.5 wt.% NaCl solution. The coating containing 2 wt.% polyaniline (relative to the mass of epoxy resin) doped with hydrochloric acid had the best anti‐corrosion properties on the Mg‐Li alloy.Originality/valuePrevious reports on the anti‐corrosion properties of polyaniline‐containing coatings focused mainly on the surface of iron, steel, aluminum and magnesium, and there have been few studies on the anti‐corrosion properties as protective coatings for Mg‐Li alloy.

As a new type of Doppler wind radar, Wind profiler radar often suffers from a variety of meteorological factors. These interferences have great effect on the detection data precision, which leads to radar data quality problem. A data processing method based on Extended Kalman Filter (EKF) is presented in this paper, which focuses on the nonlinear problems of wind data of wind profiler radar. This method is the development of traditional Kalman Filter (KF) in practical engineering applications. To verify the validity of this first-order EKF from different situation, one day’s and one moment’s wind data are selected respectively, as examples for filtering. EKF is better for data processing of wind profiler radar and has some engineering application prospects.

Transient receptor potential vanilloid type 1 (TRPV1) is a nonselective cation channel activated by capsaicin, low pH, and noxious heat and plays a key role in nociception. Understanding mechanisms for functional modulation of TRPV1 has important implications. One characteristic of TRPV1 is that channel activity induced by either capsaicin or other activators can be sensitized or modulated by factors involving different cell signaling mechanisms. In this study, we describe a novel mechanism for the modulation of TRPV1 function: TRPV1 function is modulated by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) and its analogs. We found that, in rat dorsal root ganglion neurons, although DIDS did not induce the activation of TRPV1 per se but drastically increased the TRPV1 currents induced by either capsaicin or low pH. DIDS also blocked the tachyphylaxis of the low pH-induced TRPV1 currents. 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS), a DIDS analog, failed to enhance the capsaicin-evoked TRPV1 current but increased the low pH-evoked TRPV1 currents, with an effect comparable with that of DIDS. SITS also blocked the low pH-induced tachyphylaxis. DIDS also potentiated the currents of TRPV1 channels expressed in human embryonic kidney 293 cells, with an effect of left-shifting the concentration-response curve of the capsaicin-induced TRPV1 currents. This study demonstrates that DIDS and SITS, traditionally used chloride channel blockers, can modify TRPV1 channel function in an agonist-dependent manner. The results provide new input for understanding TRPV1 modulation and developing new modulators of TRPV1 function.

Novel optically active methacrylates polymer with controlled molecular weight have been prepared simply by opening ring reaction of poly(glycidyl methacrylate) and S-(−)-α-methylbenzylamine. The structure of the novel optically active methacrylates polymer was characterized by FT-IR, and chiroptical properties of the polymer were characterized by polarimeter and circular dichroism spectrum. Thermogravimetry analysis and differential scanning calorimetry were employed to examine the thermal properties of the polymer. This preparation process was simple and the racemization of optically active monomers in preparation can be avoided. The molecular weight of optically active methacrylates polymer could be controlled by molecular weight of poly(glycidyl methacrylate) prepared by atom transfer radical polymerization.

Characteristics and optimal reaction conditions of anaerobic azoreduction by the Shewanella decolorationis S12 in the presence of zero-valent iron (ZVI) were evaluated in this study. The results showed that the presence of ZVI significantly enhanced the decolorization rate of azo dye. In the presence of 20 mmol x L(-1) ZVI, the decolorization rate of 1 mmol x L(-1) amaranth reached up to 100% by the Shewanella decolorationis S12 after 30 h incubation, which was significantly higher than 23.16% and 94.66% in the pure strain S12 and pure ZVI treatment systems, respectively. When 20 mmol x L(-1) of sodium formate was added in the medium, ZVI still improved the decolorization rate of amaranth by 20.54%. In addition, the presence of ZVI significantly increased the azo dye treatment amount in the ZVI plus S12 system. In the system with ZVI, 1 mmol x L(-1) amaranth was completely reduced 11 times in fed-batch process within 276 h, while the dye could only be completely reduced 3 times in the system without ZVI. The optimal pH and the Fe(0) dose for the ZVI plus S12 system was 9.0 and 60 mmol c L(-1), respectively. The microscale ZVI was more suitable for the decolorization than those with larger size and the nanoscale ZVI. This study may provide some useful information for improving the biodegradation of azo dye in the treatment system with ZVI.

The effects of soluble and insoluble Fe(III) on anaerobic azoreduction by Shewanella decolorationis S12 were examined in a series of experiments. Results showed that the effects of iron on anaerobic azoreduction depended on the solubility and concentration of the compounds. Azoreduction was inhibited by insoluble Fe(III) and 0.05-2 mmol/L Fe2 O3 all decelerated the azoreduction activity of 0.2 mmol/L amaranth, but the increase in the concentrations of Fe2O3 did not cause an increasing inhibition. Soluble Fe(III) of which concentration less than 0.4 mmol/L enhanced azoreduction activity of 0.2 mmol/L amaranth but there was no linear relationship between the concentration of soluble Fe(III) and azoreduction activity. Soluble Fe(III) of which concentration more than 1 mmol/L inhibited azoreduction activity of 0.2 mmol/L amaranth and an increasing concentration resulted in an increased inhibition. The inhibition was strengthened under the conditions of limited electron donor. On the other hand, soluble Fe(III) and Fe(II) could relieve the inhibition of azoreduction by dicumarol which blocked quinone cycle. It suggests that in addition to quinone cycle, there is a Fe(III)--Fe(II) cycle shuttling electrons in cytoplasmic and periplasmic environment. That is the reason why low concentration of soluble Fe(III) or Fe (II) can enhance azoreduction of S. decolorationis S12. It also indicates that insoluble Fe(III) and high concentration of soluble Fe(III) do compete with azo dye for electrons once it acts as electron acceptor. Thus, when iron and azo dye coexisted, iron could serve as an electron transfer agent or electron competitive inhibitor for anaerobic azoreduction under different conditions. High efficiency of azoreduction can be achieved through controlling the solubility and concentration of irons.

Experimental results suggested Shewanella cinica D14T is capable of humus respiration utilizing various organic acids and some important environmental pollutants (e.g., toluene. etc) as electron donors and AQS or AQDS as a sole terminal electron acceptor under anaerobic condition. The dissimilatory reduction of 1mmol/L AQDS can couple to the production of enough ATP to support cell growth about 60 generations; The oxidization of electron donors was coupled to the reduction of humus, as reduced humus increased corresponding with increasing of electron donor; The typical inhibitors such as Cu2+ which inhibited Fe-S center, Stigmatellin which was methyl-naphthoquinone model, Dicumarol which inhibited oxidized methyl-naphthoquinone transform to reduced one, Metyrapone which was specific inhibitor for P450 enzyme blocked the humus respiration seriously. These were powerful evidences for humus-respiration by D14.