摘要：
We have analyzed the photorefractive (PR) effect of a polymer composite was reported which combines a novel bi-functional poly(N-vinyl)-3-[p-nitrophenylazo]carbazolyl (PVNPAK) and 2,4,7-trinitro-9-fluorenone (TNF). PVNPAK was synthesized by a post-azo-coupling reaction, with an azo derivative as the electrooptic chromophore and carbazolyl as photoconductive moiety. The asymmetric two-beam coupling gain of 13.9 cm−1 and diffraction efficiency of 1.2% for poled polymer film fabricated using a corona poling are obtained at the wavelength of 647.1 nm, confirming photorefractivity. We interpreted this result as the orientational enhancement, in which the spatial charge field may enhance the modulated orientation of the azobenzen chromophore. It is unexpected that the photorefractive gain of 9.5 cm−1 for the unpoled polymer film also was observed without external field in two-beam coupling (TBC) experiment. This phenomenon is attributed to a light-induced orientational grating when the azobenzene groups are illuminated by polarized light.
期刊：
Asian Journal of Chemistry,2014年26(19):6579-6582 ISSN：0970-7077
通讯作者：
Chen, H.
作者机构：
[Cheng X.; Cheng S.; Chen H.; Zhang L.] School of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan, Hubei Province 430023, China;[Yan D.] School of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan, Hubei Province 430023, China
通讯机构：
[Chen, H.] S;School of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan, Hubei Province, China
关键词：
Adsorption;Bamboo leaves biomass;Isotherm;Kinetics;Malachite green
通讯机构：
[Chen, Shizhong] W;Wuhan Polytech Univ, Coll Chem & Environm Engn, 68 Xuefu South Rd, Wuhan 430023, Peoples R China.
关键词：
Inductively coupled plasma mass spectrometry;Preconcentration and separation;Speciation of chromium and its distribution;Tea leaves;Titanium dioxide nanotubes
摘要：
Titanium dioxide nanotubes (TDNTs) were used as a solid phase extraction adsorbent for chromium species by a packed microcolumn coupled with inductively coupled plasma mass spectrometry (ICP-MS), including total, suspended and soluble chromium as well as Cr(III) and Cr(VI) in tea leaves and tea infusion. The experimental results indicated that Cr(III) was quantitatively retained on TDNTs in the pH range of 5.0–8.0, while Cr(VI) remained in the solution. The total chromium was determined after reducing Cr(VI) to Cr(III). The concentration of Cr(VI) is calculated by the difference between total chromium and Cr(III). Under optimal conditions, the detection limits of this method were 0.0075 ng mL−1 for Cr(III). The relative standard deviation was 3.8% (n = 9, c = 1.0 ng mL−1). This method was applied for the analysis of the speciation of chromium and its distribution and content in tea leaves, tea infusion and a certified reference material of tea leaves with satisfactory results.
摘要：
Effect and benefits of a product or service could be analyzed and evaluated by life cycle assessment during the whole life cycle. Urban sewage treatment plants could improve and control urban water pollution escalating, but it also had certain harm to environment. Effect and benefits of urban wastewater treatment plant A and B were analyzed and evaluated, 13 factors were selected, and comprehensive benefits were researched quantificationally using the method of analytic hierarchy process. It found that urban wastewater treatment plant A who applied A/O process had better benefits than urban wastewater treatment plant B who applied BIOLAK process.
摘要：
Heterocyclic aromatic amines (HAAs) are carcinogens formed during the cooking of meats or arise in tobacco smoke. The genotoxic N-oxidized metabolites of HAAs bind to Cys residues of proteins to form arylsulfinamide adducts. However, these adducts are unstable and undergo hydrolysis during enzymatic digestion, and thus have been precluded as biomarkers of exposure to HAAs. Arylsulfinamide adducts of HAAs can undergo oxidation to form stable arylsulfonamide linkages, which are chemically stable and amenable for analysis. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a carcinogen present in cooked meat. We established a quantitative MS-based method to measure the sulfinamide adduct of PhIP formed at the cysteine(34) (Cys(34)) residue of human serum albumin (SA), following chemical oxidation of PhIP-moclified SA with m-chloroperoxybenzoic acid. Different enzyme systems (trypsin; chymotrypsin; trypsin/chymotrypsin; proteinase K; pronase E; and pronase E/leucine aminopeptidase/prolidase) were evaluated for their proficiency of digestion of SA modified with PhIP. The strongest signal was observed for the L(31)QQC*PFEDHVIC41 peptide, by ultraperformance liquid chromatography and ion trap MS. A limit of quantification value was 0.3 fmol of LQQC*PFEDHVK per mu g SA, or 2.5 adducts per 10(5) SA molecules, when assaying 0.75 mu g of SA. Biological significance This article describes a mass spectrometric based method to characterize and measure human serum albumin (SA) adducts of 2-amino-1-methyl-6-phenylimidazo[4,5-11pyridine (PhIP), a carcinogenic heterocyclic aromatic amine formed in cooked meats and tobacco smoke. PhIP undergoes metabolic activation to form reactive N-oxidized intermediates that bind to DNA and proteins. N-oxidized PhIP metabolites bind to the Cys' residue of SA to form a sulfinamide linkage. However, the linkage undergoes hydrolysis during proteolysis, precluding the employment of this adduct as a biomarker in human studies. We have shown that the sulfinamide linkage undergoes oxidation to form the [cysteine-S-yl-PhIP]-S-dioxide, a sulfonamide linked adduct which is stable toward proteolysis. The specificity and efficiency of several different proteases toward the digestion of the SA-Cysm-PhIP adduct were examined. The combination of trypsin and chymotrypsin produced the single-missed cleaved peptide LQQC*PFEDHVK in high yield. Moreover, denaturation and chemical reduction of the internal Cys disulfide bonds of SA were not required for the recovery of LQQC*PFEDHVIC The novel chemistry and proteomic approaches developed in this study may be applied to monitor biologically reactive N-oxidized intermediates of arylamines through their adduction products formed at nucleophilic Cys residues of proteins. (C) 2014 Elsevier B.V. All rights reserved.
摘要：
Reduced graphene oxide (rGO)/WO3 nanoplates composites were synthesized via a facile one-pot hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance absorption spectra (DRS), fourier transform infrared spectroscopy (FTIR) and photoluminescence spectra (PL). The photocatalytic degradation of methylene blue (MB) by the rGO/WO3 composites was investigated and optimized, suggesting the optimal amount of rGO in the composite was 15 wt%. The significantly enhanced photocatalytic activity of rGO/WO3 composites could be attributed to the excellent accepting and transporting electrons properties of rGO.
摘要：
In this paper, the use of titanium dioxide nanotubes (TDNTs) as solid-phase extraction adsorbent for on-line microcolumn separation and preconcentration of trace metals (Mn, Co, Cr, Zn, and Pb) was investigated by inductively coupled plasma mass spectrometry (ICP-MS). The effects of the experimental parameters, including pH, sample flow rate and volume, elution conditions and interfering ions on the recoveries of the analytes were investigated systematically. The experimental results showed that the analytes were adsorbed quantitatively on TDNTs in the pH range from 7.0 to 9.0 and then eluted completely with 1.5 mol L-1 HNO3 solution. Under the optimum conditions, the detection limits of this method ranged from 0.3 pg mL(-1) (Co) to 15 pg mL(-1) (Zn) with a 150-fold enrichment factor; the relative standard deviations (RSDs) for the analytes were less than 4.5% (n=9, c=1.0 ng mL(-1)). The linear range of the calibration curve spanned three orders of magnitude. This method was applied to the determination of trace elements (Mn, Co, Cr, Zn, and Pb) in natural water samples with recoveries of 94.8-104%. In order to validate this method, the certified reference material GBW 07601 Human Hair was analyzed, and the determined values were in good agreement with the certified values.
摘要：
A series of hierarchical mesoporous ZSM-5 zeolites with different morphology were successfully synthesized by the CO2-in-water microemulsion method, and mesoporosity was formed without organotemplate. The different synthesis conditions, including silica alumina molar ratio, stirring time and compressed CO2 pressure, were systematically investigated to discuss the influence of these conditions on the morphology of ZSM-5 zeolite. The resulting samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma (ICP) and nitrogen adsorption-desorption measurement. XRD results indicated that compressed CO2 route for the synthesis of MFI zeolites had a fast crystallization rate and good crystallinity. SEM images showed that the ZSM-5 hierarchical mesoporous ZSM-5 zeolite had a uniform chain-like crystal morphology, whereas silicalite-1 displayed a monodisperse crystal morphology. In addition, the nitrogen adsorption-desorption measurement provided sufficient evidence for the presence of hierarchical mesopores in ZSM-5 zeolite.
